Electronic photographic image formation device, cartridge, and drum unit

Abstract

[Problem] To develop conventional technologies. [Solution] A cartridge having a casing, a photosensitive drum, and a cap ring. The cap ring has: a driving force receiving unit for receiving driving force by engaging with a driving force application member; a braking force receiving unit for receiving braking force by engaging with a braking force application member; and a guide for moving the braking force application member relative to the driving force application member.

Description

Electrophotographic image forming apparatus, cartridge, and drum unit

[0001] The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a printer that employs an electrophotographic method, and a cartridge used in the electrophotographic image forming apparatus. The present invention also relates to a drum unit used in the electrophotographic image forming apparatus and the cartridge.

[0002] Here, an electrophotographic image forming apparatus (hereinafter also referred to as an "image forming apparatus") forms an image on a recording medium using an electrophotographic image forming method. Examples of the image forming apparatus include a copying machine, a facsimile apparatus, a printer (such as a laser beam printer, an LED printer, etc.), and a multifunction machine (multifunction printer) thereof.

[0003] The cartridge is detachable from the main body (apparatus main body) of the image forming apparatus. Examples of the cartridge include a process cartridge in which at least one of a photoreceptor and process means acting on the photoreceptor is integrally formed as a cartridge.

[0004] The drum unit is a unit having a photoreceptor drum and is used in a cartridge or an image forming apparatus.

[0005] Conventionally, in an image forming apparatus using an electrophotographic forming process, a configuration in which an electrophotographic photoreceptor (hereinafter referred to as a photoreceptor drum) and process means acting on the photoreceptor drum are integrally formed as a cartridge is known. The cartridge is detachable from the main body of the image forming apparatus.

[0006] According to this cartridge system, maintenance of the image forming apparatus can be performed by the user himself / herself without depending on a service technician, so that the maintainability can be significantly improved. Therefore, this cartridge system is widely used in image forming apparatuses.

[0007] In a configuration where the cartridge is detachable from the main body of the image forming apparatus (apparatus main body), there is a configuration in which a driving force is input from the apparatus main body to the cartridge by connecting the apparatus main body and the cartridge using a coupling (see Japanese Patent Laid-Open No. 8-328449).

[0008] The amount of torque required to drive the cartridge varies depending on the cartridge's configuration.

[0009] Japanese Patent Publication No. 2002-202690 proposes a cartridge configuration having a load generating member that applies a load to the rotation of the photoreceptor drum. The load generating member stabilizes the rotation of the photoreceptor drum by increasing the torque of the photoreceptor drum (see Japanese Patent Publication No. 2002-202690).

[0010] The challenge is to further develop the aforementioned conventional technologies.

[0011] An example of a cartridge according to the present invention is a cartridge that can be attached to and detached from the main body of an image forming apparatus, which includes a driving force applying member and a braking force applying member, and comprising: a casing; a photoreceptor drum rotatably supported by the casing; and a coupling connected to the photoreceptor drum in a manner that can transmit power, wherein the coupling comprises: a driving force receiving portion for receiving a driving force to rotate the coupling by engaging with the driving force applying member; a braking force receiving portion for receiving a braking force to load the rotation of the coupling by engaging with the braking force applying member; and a guide for moving the braking force applying member relative to the driving force applying member.

[0012] An example of a drum unit according to the present invention is a drum unit that can be attached to and detached from the main body of an image forming apparatus, which includes a driving force applying member and a braking force applying member, and comprises: a photoreceptor drum and a coupling connected to the photoreceptor drum so as to be able to transmit power, wherein the coupling has a driving force receiving portion for receiving a driving force to rotate the coupling by engaging with the driving force applying member, a braking force receiving portion for receiving a braking force to load the rotation of the coupling by engaging with the braking force applying member, and a guide for moving the braking force applying member relative to the driving force applying member.

[0013] Another example of a cartridge according to the present invention is a cartridge comprising: a casing having a first end and a second end opposite to the first end; a photoreceptor drum rotatably supported by the first and second ends of the casing; and a coupling connected to the photoreceptor drum in a drive-transmitting manner, the coupling located near the first end of the casing, wherein the coupling comprises a first shaped portion and a second shaped portion, the first shaped portion having a portion located further away from the second end of the casing than the second shaped portion in the axial direction of the coupling, the distance measured along the axial direction of the coupling from the second end of the casing to the portion of the first shaped portion decreasing as the coupling moves downstream in the rotational direction, the second shaped portion having a first side portion upstream in the rotational direction and a second side portion downstream in the rotational direction, and at least a part of the second shaped portion located further away from the axis of the coupling than the portion of the first shaped portion in the radial direction of the coupling.

[0014] Another example of a drum unit according to the present invention is a drum unit used in a cartridge, comprising: a photoreceptor drum having a first end and a second end opposite to the first end; and a coupling located near the first end of the photoreceptor drum and connected to the photoreceptor drum in a drive-transmitting manner, wherein the coupling comprises a first shaped portion and a second shaped portion, the first shaped portion having a portion located further away from the second end of the photoreceptor drum than the second shaped portion in the axial direction of the coupling, the distance measured along the axial direction of the coupling from the second end of the photoreceptor drum to the portion of the first shaped portion becoming shorter as the coupling moves downstream in a predetermined circumferential direction, the second shaped portion having a first side portion upstream in the circumferential direction and a second side portion downstream in the circumferential direction, and at least a part of the second shaped portion located further away from the axis of the coupling than the portion of the first shaped portion in the radial direction of the coupling.

[0015] Another example of a cartridge according to the present invention is a cartridge comprising: a casing having a first end and a second end opposite to the first end; a photoreceptor drum rotatably supported by the first and second ends of the casing; and a coupling located near the first end of the casing and scalably connected to the photoreceptor drum, wherein the coupling comprises: a first side facing upstream in the rotational direction of the coupling; a second side facing downstream in the rotational direction; and a guide extending toward the second end of the casing as the coupling moves downstream in the rotational direction, the guide having a portion located further away from the second end of the photoreceptor drum than the first side in the axial direction of the coupling, wherein at least a portion of the first side is located further away from the axis of the drum unit than the portion of the guide in the radial direction of the coupling.

[0016] Another example of a drum unit according to the present invention is a drum unit comprising: a photoreceptor drum having a first end and a second end opposite to the first end; a coupling located near the first end of the photoreceptor drum and connected to the photoreceptor drum in a drive-transmitting manner, wherein the coupling comprises: a first side portion directed upstream in a predetermined circumferential direction of the coupling; a second side portion directed downstream in the circumferential direction; and a guide extending toward the second end of the casing as it moves downstream in the circumferential direction, the guide comprising a portion located further away from the second end of the photoreceptor drum than the first side portion in the axial direction of the coupling, wherein at least a portion of the first side portion is located further away from the axis of the coupling than the portion of the guide in the radial direction of the coupling.

[0017] Another example of a cartridge according to the present invention is a cartridge that can be attached to and removed from the body of an electrophotographic image forming apparatus, which comprises a driving force applying member and a braking force applying member movable relative to the driving force applying member, wherein the cartridge comprises a casing, a photoreceptor drum rotatably supported by the casing, and a coupling connected to the photoreceptor drum in a manner that can transmit power, the coupling having a driving force receiving portion for receiving a driving force to rotate the coupling by engaging with the driving force applying member, and a braking force receiving portion for receiving a braking force to load the rotation of the coupling by engaging with the braking force applying member.

[0018] Another example of a drum unit according to the present invention is a drum unit that can be attached to and detached from the body of an electrophotographic image forming apparatus, comprising a driving force applying member and a braking force applying member movable relative to the driving force applying member, wherein the drum unit comprises: a photoreceptor drum rotatably supported in the casing; and a coupling connected to the photoreceptor drum in a manner that can transmit power, the coupling having: a driving force receiving portion for receiving a driving force to rotate the coupling by engaging with the driving force applying member; and a braking force receiving portion for receiving a braking force to load the rotation of the coupling by engaging with the braking force applying member.

[0019] Another example of a cartridge relating to the present invention comprises one of the drum units described above, and a casing that supports the drum unit.

[0020] Furthermore, an example of an electrophotographic image forming apparatus according to the present application comprises one of the above-mentioned cartridges and an electrophotographic image forming apparatus body.

[0021] It allows for the development of existing technologies.

[0022] Figure 1 is a perspective view of the drum coupling 143.

[0023] Figure 2 is a schematic cross-sectional view of an image forming apparatus.

[0024] Figure 3 is a cross-sectional view of the process cartridge.

[0025] Figure 4 is a cross-sectional view of an image forming apparatus.

[0026] Figure 5 is a cross-sectional view of an image forming apparatus.

[0027] Figure 6 is a cross-sectional view of an image forming apparatus.

[0028] Figure 7 is a detailed view of the tray.

[0029] Figure 8 is a perspective view of the memory element pressing unit and the cartridge pressing unit.

[0030] Figure 9 is a partial perspective view of an image forming apparatus.

[0031] Figure 10 is a side view (partially a cross-sectional view) of the process cartridge.

[0032] Figure 11 is a cross-sectional view of an image forming apparatus.

[0033] Figure 12 is a perspective view of the development separation control unit.

[0034] Figure 13 is an assembly perspective view of the process cartridge.

[0035] Figure 14 is a perspective view of the process cartridge.

[0036] Figure 15 is an assembled perspective view of the process cartridge.

[0037] Figure 16 is an assembled perspective view of the process cartridge.

[0038] Figure 17 is a single-part view of the separation-holding member R.

[0039] Figure 18 is a separate drawing of the force-applying member R.

[0040] Figure 19 is a partial cross-sectional view of the separation holding member R after assembly.

[0041] Figure 20 is an enlarged view of the area around the separation-holding member R.

[0042] Figure 21 is an enlarged view of the area around the separation holding member R.

[0043] Figure 22 is a bottom view of the drive side of the process cartridge.

[0044] Figure 23 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0045] Figure 24 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0046] Figure 25 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0047] Figure 26 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0048] Figure 27 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0049] Figure 28 is a single view of the separation holding member L.

[0050] Figure 29 is a single view of the force applying member L.

[0051] Figure 30 is an assembled perspective view after the assembly of the developing pressure spring and the separation holding member L.

[0052] Figure 31 is a partial cross-sectional view after the assembly of the separation holding member L.

[0053] Figure 32 is an enlarged view of the periphery of the separation holding member L and the force applying member L.

[0054] Figure 33 is an enlarged view of the periphery of the separation holding member.

[0055] Figure 34 is a side view seen from the driving side with the process cartridge mounted inside the image forming apparatus main body.

[0056] Figure 35 is a diagram showing the process cartridge inside the image forming apparatus main body.

[0057] Figure 36 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0058] Figure 37 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0059] Figure 38 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0060] Figure 39 is a diagram showing the operation of the developing unit inside the image forming apparatus main body.

[0061] Figure 40 shows the arrangement of the separation-holding member R and the force-applying member.

[0062] Figure 41 shows the arrangement of the separation-holding member and the force-applying member.

[0063] Figure 42 is a side view from the drive side, showing the process cartridge 100 installed inside the main body of the image forming apparatus.

[0064] Figure 43 is an exploded perspective view of the drive transmission unit 203.

[0065] Figure 44 is a cross-sectional view of the drive transmission unit 203.

[0066] Figure 45 is a perspective view of the drive transmission unit 203.

[0067] Figure 46 is a cross-sectional perspective view of the main body of the device, including the drive transmission unit 203.

[0068] Figure 47 is a front view of the drive transmission unit 203 and the drum coupling 143.

[0069] Figure 48 is an exploded view illustrating the engagement of a drum coupling.

[0070] Figure 49 is an exploded view illustrating the engagement of the drum coupling.

[0071] Figure 50 is an exploded view illustrating the engagement of a drum coupling.

[0072] Figure 51 is a cross-sectional view illustrating the engagement of a drum coupling.

[0073] Figure 52 is a perspective view illustrating a modified drum coupling.

[0074] Figure 53 is an exploded view illustrating the engagement of the drum coupling.

[0075] Figure 54 is an exploded view illustrating the engagement of a drum coupling.

[0076] Figure 55 is a perspective view of a drum unit to show a drum coupling.

[0077] Figure 56 is a diagram of a drum unit to show a drum coupling.

[0078] Figure 57 is a perspective view of a drum unit to show a drum coupling.

[0079] Figure 58 is a top view of the drum coupling.

[0080] Figure 59 is a perspective view showing the components of the drive transmission unit.

[0081] Figure 60 is a perspective view of the drive transmission unit and the drum unit.

[0082] Figure 61 is a perspective view of the drive transmission unit and the drum unit.

[0083] Figure 62 is a perspective view of the drive transmission unit and the drum unit.

[0084] Figure 63 is a perspective view of the drive transmission unit and the drum unit.

[0085] Figure 64 is a perspective view of the drive transmission unit and the drum unit.

[0086] Figure 65 is a perspective view of the drive transmission unit and the drum unit.

[0087] Figure 66 is a perspective view of the drive transmission unit and the drum unit.

[0088] Figure 67 is a perspective view of the drive transmission unit and the drum unit.

[0089] Figure 68 is a perspective view of the drive transmission unit and the drum unit.

[0090] Figure 69 is a perspective view of the drive transmission unit and the drum unit.

[0091] Figure 70 is a perspective view of the drive transmission unit and the drum unit.

[0092] Figure 71 is a perspective view of the drive transmission unit and the drum unit.

[0093] Figure 72 is a perspective view of the drive transmission unit and the drum unit.

[0094] Figure 73 is a perspective view showing a modified example of the drum coupling.

[0095] Figure 74 shows a perspective view and a front view illustrating a modified drum coupling.

[0096] Figure 75 is a perspective view of the drum unit.

[0097] Figure 76 is an exploded view illustrating the engagement of a drum coupling.

[0098] Figure 77 shows a perspective view of the drum unit and a front view of the coupling.

[0099] Figure 78 is a perspective view of the drum unit and the drive transmission unit.

[0100] Figure 79 shows a side view, perspective view, and front view of the coupling.

[0101] Figure 80 is a side view of the coupling.

[0102] Figure 81 shows a side view and a perspective view of the coupling.

[0103] Figure 82 is a schematic cross-sectional view of an image forming apparatus.

[0104] Figure 83 is a schematic cross-sectional view of the process cartridge.

[0105] Figure 84 is a schematic perspective view of the process cartridge.

[0106] Figure 85 is a schematic perspective view of the process cartridge.

[0107] Figure 86 is a schematic cross-sectional view of the process cartridge cut at the center of the rotation axis of the photoreceptor drum.

[0108] Figure 87 is an exploded perspective view of the drive transmission unit 811.

[0109] Figure 88 is a cross-sectional view taken at the center of the rotation axis of the drive transmission unit 811 when it is attached to the main body of the image forming apparatus.

[0110] Figure 89 is a schematic perspective view of another form of the drum coupling 770.

[0111] Figure 90 is a schematic perspective view illustrating the mounting of the cartridge 701 onto the main body 800 of the image forming apparatus.

[0112] Figure 91 is a schematic cross-sectional view illustrating the operation of mounting the cartridge 701 onto the main body 800 of the image forming apparatus.

[0113] Figure 92 is a schematic cross-sectional view illustrating the operation of attaching the drum coupling 770 to the main drive transmission unit 811.

[0114] Figure 93 is a schematic cross-sectional view illustrating the operation of attaching the drum coupling 770 to the main drive transmission unit 811.

[0115] Figure 94 is a perspective view illustrating a different form of process cartridge.

[0116] Figure 95 is a cross-sectional view of the drum unit.

[0117] Figure 96 is a front view of the coupling.

[0118] In Figure 97, (a) is a perspective view of the coupling, and (b) is a front view.

[0119] Figure 98 is a front view of the coupling.

[0120] Figure 99 is a perspective view showing the engagement state of the coupling and the brake engagement member.

[0121] Figure 100 is a front view of the coupling.

[0122] Figure 101 is a front view of the coupling.

[0123] Figure 102 shows the front view, perspective view, and side view of the coupling.

[0124] Figure 103 is a perspective view showing the engagement state of the coupling and the brake engagement member.

[0125] Figure 104 shows a perspective view and a side view of the drum unit.

[0126] Figure 105 shows a perspective view of the drum unit and a front view of the coupling.

[0127] Figure 106 is a cross-sectional view of the drum unit.

[0128] Figure 107 is a perspective view of the drum unit.

[0129] Figure 108 is a cross-sectional view of the coupling.

[0130] Figure 109 is a perspective view of the drum unit.

[0131] Figure 110 is a cross-sectional view of the drum unit and the drive transmission unit.

[0132] <<Example 1>> The following describes in detail, with reference to the drawings and examples, embodiments for carrying out this invention. However, unless otherwise specified, the functions, materials, shapes, and relative arrangements of the components described in this embodiment are not intended to limit the scope of this invention to those.

[0133] The first embodiment will be described below with reference to the figures.

[0134] In the following embodiments, an image forming apparatus is provided as an example in which four process cartridges can be attached and detached.

[0135] The number of process cartridges to be installed in the image forming apparatus is not limited to this number. It will be set as needed.

[0136] Furthermore, in the embodiments described below, a laser beam printer is used as an example of an image forming apparatus. [Outline configuration of the image forming apparatus]

[0137] Figure 2 is a schematic cross-sectional view of the image forming apparatus M. Figure 3 is a cross-sectional view of the process cartridge 100.

[0138] This image forming apparatus M is a four-color full-color laser printer using an electrophotographic process, and it forms color images on a recording medium S. The image forming apparatus M uses a process cartridge system, and the process cartridge is detachably mounted on the image forming apparatus body (apparatus body, electrophotographic image forming apparatus body) 170 to form color images on the recording medium S.

[0139] Here, with respect to the image forming apparatus M, the side with the front door 11 is referred to as the front, and the side opposite the front is referred to as the rear. Also, when viewing the image forming apparatus M from the front, the right side is referred to as the drive side, and the left side as the non-drive side.

[0140] Furthermore, when viewing the image forming apparatus M from the front, the upper side is defined as the top surface and the lower side as the bottom surface. Figure 2 is a cross-sectional view of the image forming apparatus M as seen from the non-driven side, with the front of the image forming apparatus M being the non-driven side, the right side being the front of the image forming apparatus M, and the back of the image forming apparatus M being the driven side.

[0141] Furthermore, the drive side of the process cartridge 100 is the side in the axial direction of the photoreceptor drum where the drum coupling (photoreceptor coupling), described later, is located. Also, the drive side of the process cartridge 100 is the side in the axial direction of the developing roller (developing member) where the developing coupling, described later, is located.

[0142] The axial direction of the photoreceptor drum is the direction parallel to the rotation axis of the photoreceptor drum, which will be described later. Similarly, the axial direction of the developing roller is the direction parallel to the rotation axis of the developing roller, which will be described later. In this embodiment, since the axis of the photoreceptor drum and the axis of the developing roller are approximately parallel, the axial direction of the photoreceptor drum and the axial direction of the developing roller are considered to be substantially the same.

[0143] The main body 170 of the image forming apparatus has four process cartridges 100 (100Y, 100M, 100C, 100K) arranged in a substantially horizontal direction: a first process cartridge 100Y, a second process cartridge 100M, a third process cartridge 100C, and a fourth process cartridge 100K.

[0144] Each of the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) has a similar electrophotographic process mechanism, but each has a different color of developer (hereinafter referred to as toner). Rotational driving force is transmitted to the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) from the drive output section of the image forming apparatus main body 170 (details will be described later).

[0145] Furthermore, bias voltages (charging bias, development bias, etc.) are supplied to each of the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) from the image forming apparatus main unit 170 (not shown).

[0146] As shown in Figure 3, each of the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) in this embodiment has a photoreceptor drum 104 and a drum holding unit 108 equipped with a charging means as a process means that acts on the photoreceptor drum 104. Furthermore, each of the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) has a developing unit 109 equipped with a developing means for developing the electrostatic latent image on the photoreceptor drum 104.

[0147] The drum holding unit 108 and the developing unit 109 are connected to each other. A more specific configuration of the process cartridge 100 will be described later.

[0148] The first process cartridge 100Y contains yellow (Y) toner in the developing frame 125, and forms a yellow toner image on the surface of the photoreceptor drum 104.

[0149] The second process cartridge 100M contains magenta (M) toner within the developing frame 125, and forms a magenta-colored toner image on the surface of the photoreceptor drum 104.

[0150] The third process cartridge 100C contains cyan (C) toner within the developing frame 125, forming a cyan toner image on the surface of the photoreceptor drum 104.

[0151] The fourth process cartridge 100K contains black (K) toner in a developing frame 125, forming a black toner image on the surface of the photoreceptor drum 104. Above the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K), a laser scanner unit 14 is provided as an exposure means. This laser scanner unit 14 outputs laser light U corresponding to image information. The laser light U then passes through the exposure window 110 of the process cartridge 100 and scans and exposes the surface of the photoreceptor drum 104.

[0152] Below the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K), an intermediate transfer unit 12 is provided as a transfer member. This intermediate transfer unit 12 has a drive roller 12e, a turn roller 12c, and a tension roller 12b, and a flexible transfer belt 12a is stretched across it.

[0153] The photoreceptor drum 104 of each of the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) has its lower surface in contact with the upper surface of the transfer belt 12a. This contact area is the primary transfer area. Inside the transfer belt 12a, a primary transfer roller 12d is provided, facing the photoreceptor drum 104.

[0154] The secondary transfer roller 6 is in contact with the turn roller 12c via the transfer belt 12a. The contact area between the transfer belt 12a and the secondary transfer roller 6 is the secondary transfer area.

[0155] Below the intermediate transfer unit 12, a feeding unit 4 is provided. This feeding unit 4 has a paper feed tray 4a that holds and accommodates the recording medium S, and a paper feed roller 4b.

[0156] In Figure 2, a fixing device 7 and a paper output device 8 are located in the upper left of the main body 170 of the image forming apparatus. The top surface of the main body 170 of the image forming apparatus is the paper output tray 13.

[0157] The toner image is fixed onto the recording medium S by the fixing means provided in the fixing device 7, and then discharged to the output tray 13. [Image forming operation]

[0158] The process for forming a full-color image is as follows:

[0159] The photoreceptor drums 104 of each of the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) are rotated at a predetermined speed (direction of arrow A in Figure 3).

[0160] The transfer belt 12a is also driven to rotate in the forward direction of the rotation of the photoreceptor drum (direction of arrow C in Figure 2) at a speed corresponding to the speed of the photoreceptor drum 104.

[0161] The laser scanner unit 14 is also driven. Synchronized with the driving of the laser scanner unit 14, the charging roller 105 in each process cartridge uniformly charges the surface of the photoreceptor drum 104 to a predetermined polarity and potential. The laser scanner unit 14 scans and exposes the surface of each photoreceptor drum 104 with laser light U according to the image signal of each color.

[0162] As a result, an electrostatic latent image corresponding to the image signal of the corresponding color is formed on the surface of each photoreceptor drum 104. The formed electrostatic latent image is developed by a developing roller 106 that is driven to rotate at a predetermined speed. In other words, the developing roller 106 is in contact with the photoreceptor drum 104, and toner moves from the developing roller 106 to the latent image on the photoreceptor drum 104, thereby developing the latent image as a toner image. In this embodiment, a contact development method is employed, in which the developing roller 106 and the photoreceptor drum 104 are in contact. However, in some cases, a non-contact development method is employed in which a small gap is left between the developing roller 106 and the photoreceptor drum 104, and toner is ejected from the developing roller 106 to the photoreceptor drum 104.

[0163] Through the electrophotographic image formation process described above, a yellow toner image corresponding to the yellow component of a full-color image is formed on the photoreceptor drum 104 of the first process cartridge 100Y. This toner image is then primary transferred onto the transfer belt 12a. A portion of the photoreceptor drum 104 is exposed to the outside of the cartridge and is in contact with the transfer belt 12a. At this contact point, the toner image on the surface of the photoreceptor drum 104 moves onto the transfer belt 12a.

[0164] Similarly, a magenta toner image corresponding to the magenta component of the full-color image is formed on the photoreceptor drum 104 of the second process cartridge 100M. This toner image is then superimposed on the yellow toner image already transferred onto the transfer belt 12a for primary transfer.

[0165] Similarly, a cyan toner image corresponding to the cyan component of the full-color image is formed on the photoreceptor drum 104 of the third process cartridge 100C. This toner image is then superimposed on the yellow and magenta toner images already transferred onto the transfer belt 12a for primary transfer.

[0166] Similarly, a black toner image corresponding to the black component of the full-color image is formed on the photoreceptor drum 104 of the fourth process cartridge 100K. This toner image is then superimposed on the yellow, magenta, and cyan toner images already transferred onto the transfer belt 12a for primary transfer.

[0167] In this way, a full-color image of unfixed toner in four colors—yellow, magenta, cyan, and black—is formed on the transfer belt 12a.

[0168] Meanwhile, the recording media S are separated and fed one by one at predetermined control timings. The recording media S are then introduced at predetermined control timings into the secondary transfer section, which is the contact point between the secondary transfer roller 6 and the transfer belt 12a.

[0169] As a result, during the process of transporting the recording medium S to the secondary transfer section, the four superimposed toner images on the transfer belt 12a are sequentially and simultaneously transferred to the surface of the recording medium S.

[0170] The configuration of the image forming apparatus is described in more detail below. [Overview of Process Cartridge Attachment / Detachment Configuration]

[0171] The tray 171 that supports the process cartridge (hereinafter referred to as the tray) will be described in more detail using Figures 42 and 4 to 7. Figure 4 is a cross-sectional view of the image forming apparatus M with the front door 11 open and the tray 171 located inside the image forming apparatus body 170. Figure 5 is a cross-sectional view of the image forming apparatus M with the front door 11 open and the tray 171 located outside the image forming apparatus body 170, with the process cartridge 100 stored inside the tray. Figure 6 is a cross-sectional view of the image forming apparatus M with the front door 11 open and the tray 171 located outside the image forming apparatus body 170, with the process cartridge 100 removed from the tray. Figure 7(a) is a partial detail view of the tray 171 as seen from the drive side in the state shown in Figure 4. Figure 7(b) is a partial detail view of the tray 171 as seen from the non-drive side in the state shown in Figure 4.

[0172] As shown in Figures 4 and 5, the tray 171 is movable relative to the image forming apparatus body 170 in the direction of arrow X1 (pushing direction) and arrow X2 (pulling direction). That is, the tray 171 is provided so as to be able to be pulled out and pushed in relative to the image forming apparatus body 170, and when the image forming apparatus body 170 is installed on a horizontal plane, the tray 171 is configured to be movable in a substantially horizontal direction. Here, the state in which the tray 171 is located outside the image forming apparatus body 170 (the state in Figure 5) is referred to as the outside position. Also, the state in which the tray 171 is located inside the image forming apparatus body 170 with the front door 11 open and the photoreceptor drum 104 and transfer belt 12a separated (the state in Figure 4) is referred to as the inside position.

[0173] Furthermore, the tray 171 has a mounting portion 171a on its outer side, which allows for the removal and attachment of process cartridges 100, as shown in Figure 6. Each process cartridge 100, mounted on the mounting portion 171a on the outer side of the tray 171, is supported by the tray 171 by a drive-side cartridge cover member 116 and a non-moving-side cartridge cover member 117, as shown in Figure 7. The process cartridge 100, while positioned on the mounting portion 171a, moves inward into the image forming apparatus body 170 as the tray 171 moves. At this time, a gap is left between the transfer belt 12a and the photoreceptor drum 104. The tray 171 can move the process cartridge 100 inward into the image forming apparatus body 170 without the photoreceptor drum 104 coming into contact with the transfer belt 12a (details will be described later).

[0174] As described above, the tray 171 allows multiple process cartridges 100 to be moved together to a position where image formation can be performed inside the image forming apparatus body 170, and also allows them to be pulled out together to the outside of the image forming apparatus body 170. [Positioning of process cartridges on the electrophotographic image forming apparatus body]

[0175] The positioning of the process cartridge 100 on the main body 170 of the image forming apparatus will be explained in more detail with reference to Figure 7.

[0176] As shown in Figure 7, the tray 171 is provided with positioning sections 171VR and 171VL for holding the cartridge 100. The positioning section 171VR has straight sections 171VR1 and 171VR2, respectively. The arc sections 116VR1 and 116VR2 of the cartridge cover member 116 shown in Figure 7 come into contact with the aforementioned straight sections 171VR1 and 171VR2, thereby determining the center of the photoreceptor drum.

[0177] Furthermore, the tray 171 shown in Figure 7 has a rotation-determining projection 171KR. By fitting with the rotation-determining recess 116KR position of the cartridge cover member 116 shown in Figure 7, the orientation of the process cartridge 100 is determined relative to the main body 170 of the apparatus.

[0178] Furthermore, the positioning portion 171VL and the rotation-determining projection 171KL are positioned opposite each other (on the non-driven side) in the longitudinal direction of the process cartridge 100, with the intermediate transfer belt 12a in between, with the positioning portion 171VR in between. In other words, on the non-driven side as well, the position of the process cartridge 100 is determined by the engagement of the arc portions 117VL1 and 117VL2 of the cartridge cover member 117 with the positioning portion 171VL, and the rotation-determining recess 117KL with the rotation-determining projection 171KL.

[0179] This ensures that the process cartridge 100 is correctly positioned relative to the tray 171.

[0180] Then, as shown in Figure 5, the process cartridge 100, which is integrated with the tray 171, is moved in the direction of arrow X1 and inserted to the position shown in Figure 4.

[0181] Then, by closing the front door 11 in the direction of arrow R, the process cartridge 100 is pressed by a cartridge pressing mechanism (not shown), which will be described later, and fixed to the image forming apparatus body 170 together with the tray 171. In conjunction with the operation of the cartridge pressing mechanism, the transfer belt 12a comes into contact with the photoreceptor 104. This state allows for the formation of an image (Figure 2).

[0182] In this embodiment, the positioning section 171VR and the positioning section 171V also serve as reinforcements to maintain rigidity during the tray 171's pulling-out operation, and therefore are made of metal sheet metal, but are not limited to this. [Cartridge pressing mechanism]

[0183] Next, the details of the cartridge pressing mechanism will be explained using Figure 8.

[0184] Figure 8(a) shows only the process cartridge 100, tray 171, cartridge pressing mechanisms 190, 191, and intermediate transfer unit 12 in the state shown in Figure 4. Figure 8(b) shows only the process cartridge 100, tray 171, cartridge pressing mechanisms 190, 191, and intermediate transfer unit 12 in the state shown in Figure 2.

[0185] Now, the process cartridge 100 receives a driving force during image formation, and also receives a reaction force from the primary transfer roller 12d (Figure 2) in the direction of arrow Z1. Therefore, in order for the process cartridge to maintain a stable position without lifting off the positioning parts 171VR and 171VL during the image formation operation, it is necessary to press the process cartridge in the direction of Z2.

[0186] To achieve these goals, in this embodiment, the image forming apparatus body 170 is provided with a cartridge pressing mechanism (190, 191).

[0187] The cartridge pressing mechanism (190, 191) is handled by the memory element pressing unit 190 on the non-driving side and the cartridge pressing unit 191 on the driving side. Further details are provided below.

[0188] By closing the front door 11 shown in Figure 4, the memory element pressing unit 190 and the cartridge pressing unit 191 shown in Figure 8 descend in the direction of arrow Z2.

[0189] The memory element pressing unit 190 has a main body-side electrical contact (not shown) that contacts the electrical contacts of a memory element (not shown) provided on the process cartridge 100. By linking it with the front door 11 via a link mechanism (not shown), the memory element 140 and the main body-side electrical contact can be made to contact or not contact each other.

[0190] In other words, the contacts come into contact when the front door 11 is closed, and separate when the front door 11 is opened.

[0191] This configuration prevents the electrical contacts from rubbing against each other as the process cartridge 100 moves together with the tray 171 inside the image forming apparatus, and also prevents the contacts from being moved out of the insertion / removal trajectory of the process cartridge 100, thus not hindering the insertion or removal of the tray 171.

[0192] This memory element pressing unit 190 also plays a role in pressing the process cartridge 100 against the aforementioned positioning unit 171VR.

[0193] Furthermore, similar to the memory element pressing unit 190, the cartridge pressing unit 121 also descends in the direction of arrow Z2 in conjunction with the closing of the front door 11, and plays the role of pressing the process cartridge 100 against the positioning unit 171VL mentioned above.

[0194] Furthermore, as will be described in more detail later, the cartridge pressing mechanism (190, 191) also simultaneously plays the role of pressing down the force-applying members 152L and 152R of the process cartridge 100, which will be described later. [Drive transmission mechanism]

[0195] Next, the drive transmission mechanism of the main unit in this embodiment will be explained using Figures 9 and 10 (a diagram in which the tray 171 is omitted for convenience).

[0196] Figure 9(a) is a perspective view of the same configuration as in Figure 4 or Figure 5, with the process cartridge 100 and tray 171 omitted. Figure 9(b) is a perspective view with the process cartridge 100, front door 11, and tray 171 omitted.

[0197] Figure 10 is a side view of the process cartridge 100 as seen from the drive side.

[0198] As shown in Figure 10, the process cartridge in this embodiment has a developing coupling section 32a and a drum coupling (photoreceptor coupling) 143.

[0199] When the front door 11 is closed (as shown in Figure 9(b)), the main unit-side drum drive coupling 180 and the main unit-side developer drive coupling 185, which transmit power to the process cartridge 100, protrude in the direction of arrow Y1 by a link mechanism (not shown).

[0200] Furthermore, by opening the front door 11 (as shown in Figure 9(a)), the drum drive coupling 180 and the developer drive coupling 185 are retracted in the direction of arrow Y2.

[0201] The couplings are retracted from the insertion and removal trajectories (X1 direction, X2 direction) of the process cartridge, so as not to obstruct the insertion and removal of the tray 171.

[0202] Furthermore, when the front door 11 is closed and the image forming apparatus body 170 is started to drive, the aforementioned drum drive coupling 180 engages with the drum coupling (coupling member, cartridge-side coupling) 143. In conjunction with this, the main body-side develop drive coupling 185 engages with the develop coupling section 32a. As a result, drive is transmitted to the process cartridge 100. Note that the transmission of drive to the process cartridge 100 is not limited to the two points described above; a mechanism may also be provided to input drive only to the drum coupling and transmit drive to the develop roller. [Intermediate Transfer Unit Configuration]

[0203] Next, the intermediate transfer unit 12 of the image forming apparatus in this embodiment will be described with reference to Figure 9.

[0204] In this embodiment, the intermediate transfer unit 12 is configured to move upward in the direction of arrow R2 by a link mechanism (not shown) when the front door 11 is closed, to the position for image formation (the position where the photoreceptor drum 104 and the intermediate transfer belt 12a come into contact).

[0205] Furthermore, by opening the front door 11, the intermediate transfer unit 12 descends in the direction of arrow R1, and the photoreceptor drum 2 and the intermediate transfer belt 12a separate.

[0206] In other words, with the process cartridge 100 set in the tray 171, the photoreceptor drum 104 and the intermediate transfer belt 12a come into contact with and separate from each other in accordance with the opening and closing operation of the front door 11.

[0207] Furthermore, the contact and separation movement is configured such that the intermediate transfer unit 12 moves up and down, tracing a rotational trajectory centered on the central point PV1 shown in Figure 4.

[0208] In this configuration, the intermediate transfer belt 12a is driven by force from a gear (not shown) arranged coaxially with the PVI. Therefore, by using the aforementioned position PV1 as the pivot point, the intermediate transfer unit 12 can be raised and lowered without moving the gear center. This eliminates the need to move the gear center, making it possible to maintain the gear position with high precision.

[0209] With the above configuration, when the process cartridge 100 is set in the tray 171, the photoreceptor drum 104 and the intermediate transfer belt 12a do not slide against each other when the tray 11 is inserted or removed, preventing damage to the photoreceptor drum 104 and image degradation due to static charge memory. [Development separation control unit]

[0210] Next, the separation mechanism of the image forming apparatus body in this embodiment will be explained using Figures 8, 11, and 12.

[0211] Figure 11 is a cross-sectional view of the image forming apparatus M, cut at the drive-side end face of the process cartridge 100. Figure 12 is a perspective view of the development spacing control unit, viewed from above and at an oblique angle.

[0212] In this embodiment, the development separation control unit 195 controls the separation contact operation of the development unit 109 with respect to the photoreceptor drum 104 by engaging with a part of the development unit 109. The development separation control unit 195 is located below the main body 170 of the image forming apparatus, as shown in Figure 8.

[0213] Specifically, the development separation control unit 195 is positioned vertically below (downward in the direction of arrow Z2) the development input coupling section 32a and the drum coupling 143.

[0214] Furthermore, the development separation control unit 195 is positioned along the longitudinal direction (Y1, Y2 direction) of the photosensitive drum 104 of the intermediate transfer belt 12. In other words, the development separation control unit 195R is positioned on the drive side and the development separation control unit 195L is positioned on the non-drive side.

[0215] As described above, by placing the development separation control unit 195 in the dead space of the image forming apparatus body 170, the main body can be made smaller.

[0216] The development spacing control unit 195R has four spacing control members 196R corresponding to the process cartridges 100 (100Y, 100M, 100C, 100K). The four spacing control members are substantially the same shape. The development spacing control unit 195R is always fixed to the main body of the image forming apparatus. However, the spacing control members 196R are configured to be movable in the W41 and W42 directions by a control mechanism (not shown). The detailed configuration will be described later.

[0217] The development spacing control unit 195L has four spacing control members 196L corresponding to the process cartridges 100 (100Y, 100M, 100C, 100K). The four spacing control members are substantially the same shape. The development spacing control unit 195L is always fixed to the main body of the image forming apparatus. However, the spacing control members 196L are configured to be movable in the W41 and W42 directions by a control mechanism (not shown). The detailed configuration will be described later.

[0218] Furthermore, in order for the development separation control unit 195 to engage with a part of the development unit 109 and control the separation and contact operation of the development unit 109, a part of the development control unit 196 and a part of the development unit 109 must overlap in the vertical direction (Z1, Z2 direction).

[0219] Therefore, after the developing unit 109 of the process cartridge 100 is inserted in the X1 direction, in order for it to overlap in the vertical direction (Z1, Z2 direction) as described above, it is necessary to make a part of the developing unit (the force-applying member 152 in this embodiment) protrude. Details will be described later.

[0220] Furthermore, if the development separation control unit 195 itself is raised in the same way as the intermediate transfer unit 12 mentioned above in order to engage, there are issues such as an increase in the operating force of the linked front door 11 and an increase in the complexity of the drive train.

[0221] In this embodiment, the developing separation control unit 195 is fixed to the image forming apparatus body 170, and a part of the developing unit 109 (force-applying member 152) is made to protrude downward (Z2) within the image forming apparatus body 170. One reason for adopting this method is to address this problem. Furthermore, since the mechanism for protruding the force-applying member 152 utilizes the same mechanisms as the memory element pressing unit 190 and cartridge pressing unit 191 described above, the aforementioned problems are not encountered, and the cost of the apparatus body is kept down.

[0222] Furthermore, the entire development separation control unit 195 is fixed to the image forming apparatus body 170. However, as will be described later, a part of it is movable in order to engage with the force-applying member 152 and apply movement so that the development unit 109 is separated from and in contact with the photoreceptor drum 104. Details will be described later. [Overall configuration of the process cartridge]

[0223] The configuration of the process cartridge will be explained using Figures 3, 13, and 14.

[0224] Figure 13 is an assembled perspective view of the process cartridge 100 as seen from the drive side, which is one side in the axial direction of the photoreceptor drum 104. Figure 14 is a perspective view of the process cartridge 100 as seen from the drive side.

[0225] In this embodiment, the first to fourth process cartridges 100 (100Y, 100M, 100C, 100K) have similar electrophotographic process mechanisms, but differ in the color of the toner they contain and the amount of toner they contain.

[0226] The process cartridge 100 includes a photoreceptor drum 104 (4Y, 4M, 4C, 4K) and process means that act on the photoreceptor drum 104. As a process means, the cartridge 100 has a charging roller 105, which is a charging means (charging member) for charging the photoreceptor drum 104. The cartridge 100 also includes a developing roller 106, which is a developing means (developing member) for developing the latent image formed on the photoreceptor drum 104, as another process means.

[0227] Other possible process means include cleaning means (such as a cleaning blade) for removing residual toner remaining on the surface of the photoreceptor drum 104. However, the image forming apparatus in this embodiment does not employ a configuration that includes cleaning means that come into contact with the photoreceptor drum 104.

[0228] The process cartridge 100 is divided into a drum holding unit 108 (108Y, 108M, 108C, 108K) and a developing unit 109 (109Y, 109M, 109C, 109K). [Configuration of the drum holding unit]

[0229] As shown in Figures 3 and 13, the drum holding unit 108 consists of a photoreceptor drum 104, a charging roller 105, a drum frame 115 which is the first frame, and the like. The photoreceptor drum 104 is integrated with the coupling 143 and drum flange 142 as a drum unit 103 (see Figure 1(a); details will be described later).

[0230] The drum unit 103 is rotatably supported by a drive-side cartridge cover member 116 and a non-moving-side cartridge cover member 117, which are provided at both ends in the longitudinal direction of the process cartridge 100. The drive-side cartridge cover member 116 and the non-moving-side cartridge cover member 117 will be described later.

[0231] Furthermore, as shown in Figures 13 and 14, a drum coupling 143 for transmitting driving force to the photoreceptor drum 104 is provided near one end of the photoreceptor drum 104 in the longitudinal direction. As explained earlier, the coupling 143 engages with the main body-side drum drive coupling 180 (see Figure 9), which serves as the drum drive output section of the image forming apparatus main body 170. The driving force of the drive motor (not shown) of the image forming apparatus main body 170 is transmitted to the photoreceptor drum 104, causing it to rotate in the direction of arrow A. The photoreceptor drum 104 also has a drum flange 142 near the other end (second end) in the longitudinal direction.

[0232] The shaft portion 143j of the coupling 143 (see Figure 1) is supported by the drive-side cartridge cover 116, and the drum flange 142 is supported by a shaft fixed to the non-drive-side cartridge cover 117. This allows the drum unit 103 to be rotatably supported within the cartridge. In other words, both ends of the photoreceptor drum 104 are rotatably supported by both ends of the cartridge casing (i.e., cartridge covers 116 and 117) via the coupling 143 and drum flange 142.

[0233] The charging roller 105 is supported by the drum frame 115 so that it can contact the photoreceptor drum 104 and rotate in a driven manner.

[0234] Of the two longitudinal (axial) sides of the drum unit 103, the side where the coupling 143 is located is the drive side, and the side where the drum flange 142 is located is the non-drive side. In other words, of the two ends of the photoreceptor drum 104 in the axial direction, the coupling 143 is fixed near the drive side end, and the drum flange 142 is fixed near the end opposite to the drive side. Of the two ends of the photoreceptor drum 104, one is sometimes called the first end and the other the second end. Figure 80 shows the drum drive side end 104a and the non-drive side end 104b of the photoreceptor drum.

[0235] Similar to the drum unit 103, of the two sides of the cartridge 100, the side where the coupling 143 is located is called the drive side, and the side opposite the drive side is called the non-drive side. For example, Figures 10 and 19 show the drive side of the cartridge. Also, Figure 16 shows the non-drive side of the cartridge.

[0236] As shown in Figures 13 and 14, the drive-side cartridge cover 116 is a component located at the drive-side end of the cartridge 100 casing, and the non-drive-side cartridge cover 117 is a component located at the non-drive-side end of the casing. The drum coupling 143, supported by the drive-side cartridge cover 116, can be considered to be located near the non-drive-side end of the cartridge 100 casing. Of the two ends of the cartridge 100, one is sometimes referred to as the first end and the other as the second end. [Developing Unit Configuration]

[0237] As shown in Figures 3 and 13, the developing unit 109 consists of a developing roller 106, a toner transport roller (toner supply roller) 107, a developing blade 130, a developing frame 125, and the like. The developing frame 125 consists of a lower frame 125a and a lid member 125b. The lower frame 125a and the lid member 125b are joined together by ultrasonic welding or the like.

[0238] The second frame (second casing), the developing frame 125, has a toner storage section 129 for storing toner supplied to the developing roller 106. The developing frame 125 also rotatably supports the developing roller 106 and the toner transport roller 107 via a drive-side bearing 126 and a non-drive-side bearing 127, which will be described later, and holds the developing blade 130 that regulates the thickness of the toner layer on the circumferential surface of the developing roller 106.

[0239] The developing blade 130 consists of an elastic member 130b, which is a sheet of metal with a thickness of approximately 0.1 mm, attached to a support member 130a, which is a metal material having an L-shaped cross-section, by welding or other means. The developing blade 130 is attached to the developing frame 125 at two points, near one end and near the other end in the longitudinal direction, by fixing screws 130c. The developing roller 106 consists of a metal core 106c and a rubber part 106d.

[0240] The developing roller 106 is rotatably supported by drive-side bearings 126 and non-drive-side bearings 127 attached to both longitudinal ends of the developing frame 125. The developing frame 125, drive-side bearings 126, and non-drive-side bearings 127 are part of the cartridge frame (casing). In a broader sense, the bearings 126 and 127 are sometimes considered part of the developing frame 125, or the bearings 126 and 127 and the developing frame 125 are collectively referred to as the developing frame.

[0241] The developing roller 106 is a roller that carries toner for developing the latent image on the photoreceptor drum 104. The toner transport roller 107 transports and supplies the toner stored in the toner storage section 129 toward the developing roller 106. The toner transport roller 107 is in contact with the developing roller 106.

[0242] Furthermore, as shown in Figures 13 and 14, a developing input coupling section (developing coupling) 32a for transmitting driving force to the developing unit 109 is provided on one longitudinal side of the developing unit 109. The developing input coupling section 32a engages with the main body side developing drive coupling 185 (see Figure 9), which serves as the developing drive output section of the image forming apparatus main body 170, and the driving force of the drive motor (not shown) of the image forming apparatus main body 170 is input to the developing unit 109.

[0243] The driving force input to the developing unit 109 is transmitted by a drive train (not shown) provided within the developing unit 109, thereby rotating the developing roller 106 in the direction of arrow D in Figure 3. Similarly, the driving force received by the developing input coupling unit 32a also rotates the toner transport roller 107, supplying toner to the developing roller 106.

[0244] On one longitudinal side of the developing unit 109, a developing cover member 128 is provided to support and cover the developing input coupling section 32a and a drive row (not shown). The outer diameter of the developing roller 106 is set to be smaller than the outer diameter of the photoreceptor drum 104. In this embodiment, the outer diameter of the photoreceptor drum 104 is set in the range of Φ18 to Φ22, and the outer diameter of the developing roller 106 is set in the range of Φ8 to Φ14. Setting the outer diameters to these ranges allows for efficient arrangement. [Assembly of drum holding unit and developing unit]

[0245] The assembly of the drum holding unit 108 and the developing unit 109 will be explained using Figure 13. The drum holding unit 108 and the developing unit 109 are connected by a drive-side cartridge cover member 116 and a non-moving-side cartridge cover member 117, which are provided at both ends of the process cartridge 100 in the longitudinal direction.

[0246] A drive-side cartridge cover member 116, located on one longitudinal side (drive side) of the process cartridge 100, is provided with a developing unit support hole 116a for pivotably supporting the developing unit 109. Similarly, a non-drive-side cartridge cover member 117, located on the other longitudinal side (non-drive side) of the process cartridge 100, is provided with a developing unit support hole 117a for pivotably supporting the developing unit 109.

[0247] Furthermore, the drive-side cartridge cover member 116 and the non-moving-side cartridge cover member 117 are provided with drum support holes 116b and 117b for rotatably supporting the photoreceptor drum 104. On the drive side, the outer diameter of the cylindrical portion 128b of the developing cover member 128 is fitted into the developing unit support hole 116a of the drive-side cartridge cover member 116. On the non-drive side, the outer diameter of the cylindrical portion (not shown) of the non-drive side bearing 127 is fitted into the developing unit support hole 117a of the non-moving-side cartridge cover member 117.

[0248] Furthermore, both longitudinal ends of the photoreceptor drum 104 are fitted into the drum support holes 116b of the drive-side cartridge cover member 116 and the drum support holes 117b of the non-moving cartridge cover member 117. The drive-side cartridge cover member 116 and the non-moving cartridge cover member 117 are then fixed to the drum frame 115 of the drum holding unit 108 using screws, adhesive, etc. (not shown). As a result, the developing unit 109 is rotatably supported by the drive-side cartridge cover member 116 and the non-moving cartridge cover member 117. The developing unit 109 is movable (rotatable) relative to the drum holding unit 108, and this movement allows the developing roller 106 to move relative to the photoreceptor drum 104. The developing roller 106 can be positioned to act on the photoreceptor drum 104 during image formation.

[0249] The drum frame 115 and the cover members 116 and 117 are part of the cartridge frame (casing). More specifically, they are the frame of the drum holding unit 108. Also, since both cover members 116 and 117 are fixed to one end and the other end of the drum frame 115, respectively, the cover members 116 and 117 are sometimes considered part of the drum frame 115. Alternatively, the cover members 116 and 117 and the drum frame 115 are sometimes collectively referred to as the drum frame.

[0250] Furthermore, the frame of the drum holding unit 108 (115, 116, 117) and the frame of the developing unit (125, 126, 127) may be referred to as the first frame (first casing) and the other as the second frame (second casing). In addition, the frame of the drum holding unit 108 (115, 116, 117) and the frame of the developing unit (125, 126, 127) may not be particularly distinguished, and both may be collectively referred to as the cartridge frame (cartridge casing).

[0251] Figure 14 shows the drum holding unit 108 and the developing unit 109 assembled as a single unit and formed as a process cartridge 100 by the above process.

[0252] The axis connecting the center of the developing unit support hole 116a of the drive-side cartridge cover member 116 and the center of the developing unit support hole 117a of the non-moving cartridge cover member 117 is referred to as the pivot axis K. Here, the cylindrical portion 128b of the drive-side developing cover member 128 is coaxial with the developing input coupling 74. In other words, the developing unit 109 is configured to receive driving force from the image forming apparatus body 170 at this pivot axis K. Furthermore, the developing unit 109 is rotatably supported around the pivot axis K. [Configuration of the separation contact mechanism]

[0253] This embodiment will describe in detail the configuration by which the photosensitive drum 104 of the process cartridge 100 and the developing roller 106 of the developing unit 109 perform separation and contact. The process cartridge has a separation and contact mechanism 150R on the drive side and a separation and contact mechanism 150L on the non-drive side. Figure 15 shows an assembled perspective view of the drive side of the developing unit 109 including the separation and contact mechanism 150R. Figure 16 shows an assembled perspective view of the non-drive side of the developing unit 109 including the separation and contact mechanism 150L. First, the details of the separation and contact mechanism 150R on the drive side will be described, followed by the description of the separation and contact mechanism 150L on the non-drive side.

[0254] Furthermore, since the separation and contact mechanism has almost identical function on both the drive and non-drive sides, the letter R is added to the end of the reference numeral for each component on the drive side. On the non-drive side, the reference numerals for each component are the same as those on the drive side, with L added to the end.

[0255] The separation contact mechanism 150R includes a separation holding member 151R which is a regulating member, a force applying member 152R which is a pressing member, and a tension spring 153.

[0256] The separation contact mechanism 150L includes a separation holding member 151L, which is a regulating member, a force applying member 152L, which is a pressing member, and a tension spring 153. [Detailed description of the separation holding member R]

[0257] Here, the separation-holding member 151R will be explained in detail with reference to Figure 17.

[0258] Figure 17(a) is a front view of the separation holding member 151R as seen from the longitudinal direction on the drive side of the process cartridge 100. Figures 17(b) and 17(c) are perspective views of the separation holding member 151R. Figure 17(d) is a view of the separation holding member 151R in the direction of arrow Z2 in Figure 17(a) (vertically upward in the image formation state). The separation holding member 151R has an annular support receiving portion 151Ra and a separation holding portion 151Rb that protrudes radially from the support receiving portion 151Ra. The tip of the separation holding portion 151Rb has a separation holding surface 151Rc that is arc-shaped around the pivot axis H of the separation holding member and inclined at an angle θ1 with respect to a line HA parallel to the pivot axis H of the separation holding member. The angle θ1 is set to satisfy equation (1). 0°≦θ1≦45°・・・(1)

[0259] Furthermore, the separation-holding member 151R has a second restricted surface 151Rk adjacent to the separation-holding surface 151Rc. In addition, the separation-holding member 151R has a second pressed portion 151Rd that protrudes in the Z2 direction from the support-receiving portion 151Ra, and has an arc-shaped second pressed surface 151Re that protrudes from the second pressed portion 151Rd in the direction of the pivot axis H of the separation-holding member of the support-receiving portion 151Ra.

[0260] Furthermore, the separation-holding member 151R has a main body portion 151Rf connected to the support receiving portion 151Ra, and the main body portion 151Rf has a spring-hanging portion 151Rg that protrudes in the direction of the pivot axis H of the separation-holding member of the support receiving portion 151Ra. Furthermore, the main body portion 151Rf has a rotation-preventing portion 151Rm that protrudes in the Z2 direction, and a rotation-preventing surface 151Rn is provided in a direction facing the second pressed surface 151Re. [Detailed explanation of force-applying member R]

[0261] Here, the force-applying member 152R will be explained in detail with reference to Figure 18.

[0262] Figure 18(a) is a front view of the force-applying member 152R as seen from the longitudinal direction of the process cartridge 100, and Figures 18(b) and 18(c) are perspective views of the force-applying member 152R.

[0263] The force-applying member 152R has an elongated oval-shaped support receiving portion 152Ra. Here, the longitudinal direction of the elongated shape of the elongated support receiving portion 152Ra is denoted by arrow LH, with arrow LH1 pointing upwards and arrow LH2 pointing downwards. Furthermore, the direction in which the elongated support receiving portion 152Ra is formed is denoted by HB. The force-applying member 152R has a projection 152Rh formed downstream of the elongated support receiving portion 152Ra in the direction of arrow LH2. The elongated support receiving portion 152Ra and the projection 152Rh are connected by the main body portion 152Rb. On the other hand, the force-applying member 152R has a pressed portion 152Re that protrudes in the direction of arrow LH1 and approximately perpendicular to the direction of arrow LH1, and has an arc-shaped pressed surface 152Rf on the downstream side in the direction of arrow LH1, and a pressing restricting surface 152Rg on the upstream side. Furthermore, the force-applying member 152R has a first storage-restricting surface 152Rv that extends from the main body portion 152Rb upstream of the protruding portion 152 in the direction of arrow LH2, and a second storage-restricting surface 152Rw that is adjacent to the first storage-restricting surface 152Rv and substantially parallel to the first pressing surface 152Rq.

[0264] The projection 152Rh has a first force-receiving portion 152Rk and a second force-receiving portion 152Rn, which are located at the end of the LH2 direction and opposite each other in a direction substantially perpendicular to the LH2 direction. The first force-receiving portion 152Rk and the second force-receiving portion 152Rn each have a first force-receiving surface 152Rm and a second force-receiving surface 152Rp, respectively, which extend in the HB direction and have an arc shape. The projection 152Rh also has a spring-hanging portion 152Rs and a locking portion 152Rt that project in the HL direction, and the locking portion 152Rt has a locking surface 152Ru that faces the same direction as the first force-receiving surface 152Rp.

[0265] Furthermore, the force-applying member 152R is part of the main body portion 152Rb and is positioned upstream of the second force-receiving portion 152Rn in the direction of arrow LH2, and has a first pressing surface 152Rq facing the same direction as the second force-receiving surface 152Rp. In addition, the force-applying member 152R has a second pressing surface 152Rr that is perpendicular to the first storage restriction surface 152Rv and is positioned opposite the first pressing surface 152Rq.

[0266] Furthermore, when the process cartridge 100 is mounted on the image forming apparatus body 170, the LH1 direction is approximately the same as the Z1 direction, and the LH2 direction is approximately the same as the Z2 direction. Also, the HB direction is approximately the same as the longitudinal direction of the process cartridge 100. [Assembly of the separation contact mechanism R]

[0267] Next, the assembly of the separation contact mechanism will be explained using Figures 10, 15 to 19. Figure 19 is a perspective view of the process cartridge 100 after the separation holding member 151R has been assembled, as seen from the drive side.

[0268] As mentioned above, as shown in Figure 15, the developing unit 109 is fitted with the outer diameter of the cylindrical portion 128b of the developing cover member 128 into the developing unit support hole 116a of the drive-side cartridge cover member 116. In this way, the developing unit 109 is rotatably supported with respect to the photoreceptor drum 104 around the pivot axis K. The developing cover member 128 also has a cylindrical first support portion 128c and a second support portion 128k that protrude in the direction of the pivot axis K.

[0269] The outer diameter of the first support portion 128c fits with the inner diameter of the support receiving portion 151Ra of the separation holding member 151R, thereby rotatably supporting the separation holding member 151R. Here, the pivot point of the separation holding member 151R assembled to the developing cover member 128 is defined as the separation holding member pivot axis H. The developing cover member 128 has a first retaining portion 128d that protrudes in the direction of the separation holding member pivot axis H. As shown in Figure 15, the movement of the separation holding member 151R assembled to the developing cover member 128 in the direction of the separation holding member pivot axis H is restricted by the first retaining portion 128d contacting the separation holding member 151R.

[0270] Furthermore, the outer diameter of the second support portion 128k fits with the inner wall of the oval support receiving portion 152Ra of the force-applying member 152R, supporting the force-applying member 152R so that it can rotate and move in the oval direction. Here, the pivot point of the force-applying member 152R assembled to the developing cover member 128 is defined as the force-applying member pivot axis HC. As shown in Figure 15, the movement of the force-applying member 152R assembled to the developing cover member 128 in the direction of the force-applying member pivot axis HC is restricted by the second retaining portion 128m contacting the separation holding member 151R.

[0271] Figure 10 is a cross-sectional view in which a portion of the drive-side cartridge cover member 116 and a portion of the develop-side cover member 128 are partially omitted by the partial cross-sectional line CS, so that the fitting portion of the oval support receiving portion 151Ra of the force-applying member 152R and the cylindrical portion 128b of the develop-side cover member 128 is visible. The separation contact mechanism 150R is equipped with a tension spring 153 as a biasing means that biases the separation holding member 151R to rotate in the direction of arrow B1 in the figure around the pivot axis H of the separation holding member, and also biases the force-applying member 152R in the direction of arrow B3.

[0272] Note that the direction of arrow B3 is approximately parallel to the longitudinal direction LH2 of the oval support receiving portion 152Ra of the force-applying member 152R (see Figure 18). The tension spring 153 is assembled between the spring attachment portion 151Rg provided on the separation-holding member 151R and the spring attachment portion 152Rs provided on the force-applying member 152R. The tension spring 153 applies a force to the spring attachment portion 151Rg of the separation-holding member 151R in the direction of arrow F2 in Figure 10, thereby providing a biasing force that rotates the separation-holding member 151R in the direction of arrow B1. Furthermore, the tension spring 153 applies a force to the spring attachment portion 152Rs of the force-applying member 152R in the direction of arrow F1, thereby providing a biasing force that moves the force-applying member 152R in the direction of arrow B3.

[0273] Let GS be the line connecting the spring attachment portion 151Rg of the separation-holding member 151R and the spring attachment portion 152Rs of the force-holding member 152R. Let HS be the line connecting the spring attachment portion 152Rs of the force-applying member 152R and the pivot axis HC of the force-applying member. Here, the angle θ2 formed by line GS and line HS is set to satisfy the following equation (2), with clockwise rotation around the spring attachment portion 152Rs of the force-applying member 152R being positive. As a result, the force-applying member 152R is biased to rotate in the direction of arrow BA with the pivot axis HC of the force-applying member as the center of rotation. 0°≦θ2≦90°・・・(2)

[0274] As shown in Figure 15, the developing drive input gear 132 is positioned so that the inner diameter of the cylindrical portion 128b of the developing cover member 128 fits with the outer diameter of the cylindrical portion 32b of the developing drive input gear 132, and in addition, the support portion 126a of the drive-side bearing 126 fits with a cylindrical portion (not shown) of the developing drive input gear. This arrangement transmits driving force to the developing roller gear 131, the toner transport roller gear 133, and other gears.

[0275] In this embodiment, the mounting positions of the separation holding member 151R and the force applying member 152R are as follows. As shown in Figure 15, in the direction of the oscillation axis K, the separation holding member 151R is positioned on the side where the drive-side cartridge cover member 116 is positioned (outer side in the longitudinal direction), sandwiching the developing cover member 128. The force applying member 152R is positioned on the side where the developing drive input gear 13 is positioned (inner side in the longitudinal direction). However, the positions are not limited to these, and the positions of the separation holding member 151R and the force applying member 152R may be swapped, or the separation holding member 151R and the force applying member 152R may be positioned on one side in the direction of the oscillation axis K with respect to the developing cover member 128. Furthermore, the order in which the separation holding member 151R and the force applying member 152R are positioned may be swapped.

[0276] The developing cover member 128 is then fixed to the developing frame 125 via the drive bearing 126 to form the developing unit 109. In this embodiment, the fixing method is as shown in Figure 15, by fixing screws 145 and an adhesive (not shown), but the fixing method is not limited to this, and other joining methods such as welding by heating or pouring and hardening resin may also be used.

[0277] Here, Figure 20 is a cross-sectional view in which the area around the separation holding portion 151R in Figure 10 is enlarged for explanatory purposes, and the tension spring 153 and a part of the separation holding member 151R are partially omitted by the partial cross-sectional line CS4. The force-applying member 152R is positioned by the biasing force of the tension spring 153 in the direction F1 in the figure, so that the first restricting surface 152Rv of the force-applying member 152R contacts the first restricting surface 128h of the developing cover member 128. Also, the second restricting surface 152Rw of the force-applying member 152R contacts the second restricting surface 128q of the developing cover member 128 and is positioned. This position is referred to as the storage position (reference position) of the force-applying member 152R. Furthermore, the separation-holding member 151R rotates in the B1 direction around the pivot axis H of the separation-holding member due to the biasing force of the tension spring 153 in the F2 direction, and the second pressed portion 151Rd of the separation-holding member 151R comes into contact with the second pressing surface 152Rr of the force-applying member 152R, stopping the rotation. This position is referred to as the separation-holding position (restriction position) of the separation-holding member 151R.

[0278] Furthermore, Figure 21 is an enlarged view of the area around the separation holding part 151R in Figure 10 for illustrative purposes, with the tension spring 153 omitted. Here, we consider the case where the process cartridge 100 having the separation contact mechanism 150R described in this embodiment is dropped in the direction of JA in Figure 21 during logistics. At this time, the separation holding member 151R receives a rotational force in the direction of arrow B2 due to its own weight around the separation holding oscillation axis H. When it starts to rotate in the direction of B2 for the above reason, the rotation prevention surface 151Rn of the separation holding member 151R comes into contact with the locking surface 152Ru of the force applying member 152R, and the separation holding member 151R receives a force in the direction of F3 in the figure to suppress rotation in the direction of B2. This prevents the separation holding member 151R from rotating in the direction of B2 during logistics, and prevents damage to the separated state of the photoreceptor drum 104 and the developing unit 109.

[0279] In this embodiment, a tension spring 153 was given as a biasing means for biasing the separation-holding member 151R to the separation-holding position and the force-applying member 152R to the storage position, but the biasing means is not limited to this. For example, a torsion coil spring, a leaf spring, etc. may be used as a biasing means to bias the force-applying member 152R to the storage position and the separation-holding member 151R to the separation-holding position. Furthermore, the material of the biasing means can be metal, molded metal, etc., as long as it has elasticity and can bias the separation-holding member 151R and the force-applying member 152R.

[0280] As described above, the developing unit 109 equipped with the separation contact mechanism 150R is integrally coupled with the drum holding unit 108 by the drive-side cartridge cover member 116 (as shown in Figure 19).

[0281] Figure 22 shows a view from the direction of arrow J in Figure 19. As shown in Figure 15, the drive-side cartridge cover 116 of this embodiment has a contact surface 116c. The contact surface 116c is formed with an inclination of angle θ3 with respect to the pivot axis K, as shown in Figure 22. It is desirable that angle θ3 be the same angle as the angle θ1 that forms the separation holding surface 151Rc of the separation holding member 151R, but it is not limited to this. Furthermore, as shown in Figures 15 and 19, when the drive-side cartridge cover member 116 is assembled to the developing unit 109 and the drum holding unit 108, the contact surface 116c faces the separation holding surface 151Rc of the separation holding member 151R, which is located in the separation holding position. The contact surface 116c comes into contact with the separation holding surface 151Rc due to the biasing force of the developing pressure spring 134, which will be described later. When the engaging surface 116Rc and the separation holding surface 151Rc come into contact, the developing unit 109 is positioned so that it is separated from the developing roller 106 and the photoreceptor drum 104 by a gap P1. This state in which the developing roller 106 (developing member) is separated from the photoreceptor drum 104 by a gap P1 by the separation holding member 151R is called the separated position (retracted position) of the developing unit 109 (see Figure 42(a)).

[0282] Here, the separated state and contact state of the process cartridge 100 will be explained in detail using Figure 42.

[0283] Figure 42 is a side view from the drive side with the process cartridge 100 installed inside the image forming apparatus body 170. Figure 42(a) shows the developing unit 109 separated from the photoreceptor drum 104. Figure 42(b) shows the developing unit 109 in contact with the photoreceptor drum 104.

[0284] First, with the separation-holding member 151R positioned in the separation-holding position and the developing unit 109 in the separation position, the pressed portion 152Re of the force-applying member 152R is pressed in the ZA direction. This causes the protruding portion 152Rh of the force-applying member 152R to protrude from the process cartridge 100. As described above, the second pressed surface 151Re of the separation-holding member 151R is in contact with the second pressing surface 152Rr of the force-applying member 152R by the tension spring 153. Therefore, when the second force-receiving portion 152Rn is pressed in the direction of arrow W42, the force-applying member 152R rotates in the direction of arrow BB around the force-applying member pivot axis HC, causing the separation-holding member 151R to rotate in the direction of arrow B2. When the separation-holding member 151R rotates in the direction of arrow B2, the separation-holding surface 151Rc separates from the contact surface 116c, and the developing unit 109 becomes able to rotate from the separated position around the pivot axis K in the direction of arrow V2. In other words, the developing unit 109 rotates from the separated position in the direction of V2, and the developing roller 106 of the developing unit 109 comes into contact with the photoreceptor drum 104. Here, the position of the developing unit 109 where the developing roller 106 and the photoreceptor drum 104 come into contact is called the contact position (developing position) (the state shown in Figure 42(b)). The position where the separation-holding surface 151Rc of the separation-holding member 151R separates from the contact surface 116c is called the separation release position (allowable position). When the developing unit 109 is in the contact position, the second restricting surface 151Rk of the separation holding member 151R comes into contact with the second restricting surface 116d of the drive-side cartridge cover 116, thereby maintaining the separation holding member 151R in the release position.

[0285] Furthermore, the drive-side bearing 126 has a first pressed surface 126c which is perpendicular to the oscillating axis K. Since the drive-side bearing 126 is fixed to the developing unit 109, when the developing unit 109 is in contact position, it presses the first force-receiving portion 152Rk of the force-applying member 152R in the direction of arrow 41. As a result, the first pressing surface 152Rq comes into contact with the first pressed surface 126c, causing the developing unit 109 to rotate around the oscillating axis K in the direction of arrow V1 and move to the separated position (the state shown in Figure 42(a)). Here, when the developing unit 109 moves from the contact position to the separated position, the direction in which the first force-receiving surface 126c moves is indicated by arrow W41 in Figures 42(a) and (b). Also, the opposite direction of arrow W41 is arrow W42, and arrows W41 and W42 are approximately horizontal (X1, X2 directions). As described above, the second force-receiving surface 152Rp of the force-applying member 152R assembled to the developing unit 109 is located upstream of the first force-receiving surface 126c of the drive-side bearing 126 in the direction of arrow W41. Furthermore, the first force-receiving surface 126c and the second force-receiving surface 151Re of the separation-holding member 151R are positioned so that at least a portion of them overlap in the W1 and W2 directions.

[0286] The detailed operation of the separation and contact mechanism 150R within the image forming apparatus body 170 will be described next. [Mounting the process cartridge into the image forming apparatus body]

[0287] Next, using Figures 12, 23, and 24, the engagement operation of the separation contact mechanism 150R of the process cartridge 100 and the development separation control unit 195 of the image forming apparatus body 170 when the process cartridge 100 is mounted on the image forming apparatus body 170 will be explained. Note that these figures are cross-sectional views in which a part of the development cover member 128 and a part of the drive-side cartridge cover member 116 are partially omitted by partial cross-sectional lines CS1 and CS2, respectively, for illustrative purposes.

[0288] Figure 23 is a view of the process cartridge 100 from the drive side when the process cartridge 100 is mounted on a cartridge tray 171 (not shown) of the image forming apparatus M and the cartridge tray 171 is inserted into the first mounting position. In this figure, components other than the process cartridge 100, cartridge pressing unit 121, and separation control member 196R are omitted.

[0289] As previously explained, the image forming apparatus body 170 of this embodiment has a separation control member 196R corresponding to each process cartridge 100, as described above. The separation control member 196R is positioned on the lower side of the image forming apparatus body 170, more so than the separation holding member 151R, when the process cartridge 100 is in the first inner position and the second inner position. The separation control member 196R protrudes toward the process cartridge 100 and has a first force-applying surface 196Ra and a second force-applying surface 196Rb facing each other via a space 196Rd. The first force-applying surface 196Ra and the second force-applying surface 196Rb are connected via a connecting portion 196Rc on the lower side of the image forming apparatus body 170. The separation control member 196R is also rotatably supported on the control plate 197 with respect to a pivot center 196Re. The separation member 196R is always biased in the E1 direction by a biasing spring. Furthermore, since the control sheet metal 197 is configured to be movable in the W41 and W42 directions by a control mechanism (not shown), the separation control member 196R is configured to be movable in the W41 and W42 directions.

[0290] As described above, in conjunction with the transition of the front door 11 of the image forming apparatus body 170 from the open state to the closed state, the cartridge pressing unit 121 descends in the direction of arrow ZA, and the first force-applying part 121a comes into contact with the pressed surface 152Rf of the force-applying member 152R. After the cartridge pressing unit 121 descends to a predetermined position which is the second mounting position, the protruding part 152Rh of the force-applying member 152R protrudes downward in the Z2 direction of the process cartridge 100 (state shown in Figure 24). This position is referred to as the protruding position of the force-applying member 152R. Once this operation is complete, as shown in Figure 24, a gap T4 is formed between the first force-applying surface 196Ra of the separation control member 196R and the first force-receiving surface 152Rp of the force-applying member 152R, and a gap T3 is formed between the second force-applying surface 196Rb and the second force-receiving surface 152Rp. The separation control member 196R is then positioned in the second mounting position where it does not act on the force-applying member 152R. This position of the separation control member 196R is referred to as the home position. At this time, the first force receiving surface 152Rp of the force applying member 152R and the first force applying surface 196Ra of the separation control member 196R are arranged so that they partially overlap in the W1 and W2 directions. Similarly, the second force receiving surface 152Rp of the force applying member 152R and the second force applying surface 196Rb of the separation control member 196R are arranged so that they partially overlap in the W1 and W2 directions. [Contact operation of the developing unit]

[0291] Next, the operation by which the photoreceptor drum 104 and the developing roller 106 come into contact with each other by the separation contact mechanism 150R will be explained in detail with reference to Figures 24 to 26. Note that these figures are cross-sectional views in which parts of the developing cover member 128, the drive-side cartridge cover member 116, and the drive-side bearing 126 are partially omitted by partial cross-sectional lines CS1, CS2, and CS3, respectively, for illustrative purposes.

[0292] In this embodiment, the development input coupling 32 receives a driving force from the image forming apparatus body 170 in the direction of arrow V2 in Figure 24, causing the development roller 106 to rotate. In other words, the development unit 109 having the development input coupling 32 receives torque from the image forming apparatus body 170 in the direction of arrow V2 around the pivot axis K. As shown in Figure 24, when the development unit 109 is in the separated position and the separated holding member 151R is in the separated holding position, the development unit 109 receives this torque and the biasing force from the development pressure spring 134, which will be described later. Even in this case, the separated holding surface 151Rc of the separated holding member 151R contacts the contact surface 116c of the drive-side cartridge cover member 116, and the posture of the development unit 109 is maintained in the separated position.

[0293] In this embodiment, the separation control member 196R is configured to be movable from the home position in the direction of arrow W42 in Figure 24. When the separation control member 196R moves in the direction of W42, the second force-applying surface 196Rb of the separation control member 196R and the second force-receiving surface 152Rp of the force-applying member 152R come into contact, and the force-applying member 152R rotates in the direction of BB with the force-applying member pivot axis HC as the center of rotation. Furthermore, as the force-applying member 152R rotates, the second pressing surface 152Rr of the force-applying member 152R comes into contact with the second pressed surface 151Re of the separation-holding member 151R, causing the separation-holding member 151R to rotate in the direction of B2. The separation-holding member 151R is then rotated by the force-applying member 152R until the separation-release position is reached, where the separation-holding surface 151Rc and the contact surface 116c are separated. Here, the position of the separation control member 196R that moves the separation holding member 151R to the separation release position, as shown in Figure 25, is referred to as the first position.

[0294] In this way, the separation control member 196R moves the separation holding member 151R to the separation release position. Then, the developing unit 109 rotates in the V2 direction due to the torque received from the image forming apparatus body 170 and the developing pressure spring 134 (described later), and moves to the contact position where the developing roller 106 and the photoreceptor drum 104 come into contact (the state shown in Figure 25). At this time, the separation holding member 151R, which is biased in the direction of arrow B1 by the tension spring 153, is maintained in the separation release position when the second restricted surface 151Rk comes into contact with the second restricted surface 116d of the drive-side cartridge cover member 116. After that, the separation control member 196R moves in the W41 direction and returns to the home position. At this time, the force-applying member 152R rotates in the BA direction by the tension spring 153, and transitions to a state where the first pressing surface 152Rq of the force-applying member 152R and the first pressing surface 126c of the drive-side bearing 126 come into contact (state shown in Figure 26).

[0295] As a result, the aforementioned gaps T3 and T4 are reformed, and the separation control member 196R is positioned so that it does not act on the force-applying member 152R. Note that the transition from the state in Figure 25 to the state in Figure 26 occurs without any delay.

[0296] As described above, in this embodiment, the separation control member 196R moves from the home position to the first position, which rotates the force-applying member 152R and moves the separation holding member 151R from the separation holding position to the separation release position. This allows the developing unit 109 to move from the separation position to the contact position where the developing roller 9 and the photoreceptor drum 104 come into contact. Note that the position of the separation control member 196R in Figure 26 is the same as the state in Figure 24. [Separation operation of the developing unit]

[0297] Next, the movement of the developing unit 109 from the contact position to the separated position by the separation contact mechanism 150R will be explained in detail using Figures 26 and 27. Note that these figures are cross-sectional views in which a portion of the developing cover member 128, a portion of the drive-side cartridge cover member 116, and a portion of the drive-side bearing 126 are partially omitted by the partial cross-sectional line CS, respectively, for illustrative purposes.

[0298] In this embodiment, the separation control member 196R is configured to be movable from the home position in the direction of arrow W41 in Figure 26. When the separation control member 196R moves in the direction of W41, the first force-applying surface 196Rb and the first force-receiving surface 152Rm of the force-applying member 152R come into contact, and the force-applying member 152R rotates in the direction of arrow BB around the force-applying member pivot axis HC. Then, the first pressing surface 152Rq of the force-applying member 152R comes into contact with the first pressed surface 126c of the drive-side bearing 126, causing the developing unit 109 to rotate from the contact position in the direction of arrow V1 around the pivot axis K (state shown in Figure 27). At this time, the pressed surface 152Rf of the force-applying member 152R has an arc shape, and the center of this arc is positioned to coincide with the pivot axis K. As a result, when the developing unit 109 moves from the contact position to the separation position, the force received by the cartridge pressing unit 121 on the pressed surface 152Rf of the force applying member 152R is directed in the direction of the pivot axis K. Therefore, it can be operated in a way that does not hinder the rotation of the developing unit 109 in the direction of arrow V1. The separation holding member 151R separates from the second restricted surface 151Rk of the separation holding member 151R and the second restricted surface 116d of the drive-side cartridge cover member 116, and the separation holding member 151R rotates in the direction of arrow B1 due to the biasing force of the tension spring 153. As a result, the separation holding member 151R rotates until the second pressed surface 151Re contacts the second pressing surface 152Rr of the force applying member 152R, and upon contact, moves to the separation holding position. When the developing unit 109 moves from the contact position to the separated position by the separation control member 196R, and the separation holding member 151R is in the separated holding position, a gap T5 is formed between the separated holding surface 151Rc and the contact surface 116c, as shown in Figure 27. Here, the position shown in Figure 27, where the developing unit 109 is rotated from the contact position to the separated position, and the separation holding member 151 can move to the separated holding position, is referred to as the second position of the separation control member 196R.

[0299] Then, the separation control member 196R moves in the direction of arrow W42, returning from the second position to the home position. As a result, the separation holding member 151R maintains its separation holding position, and the developing unit 109 rotates in the direction of arrow V2 due to the torque received from the image forming apparatus body 170 and the developing pressure spring 134 (described later), causing the separation holding surface 151Rc and the contact surface 116c to come into contact. In other words, the developing unit 109 maintains its separated position by the separation holding member 151R, and the developing roller 106 and the photoreceptor drum 104 are separated by a gap P1 (the state shown in Figures 24 and 42(a)). As a result, the aforementioned gaps T3 and T4 are reformed, and the separation control member 196R is positioned so that it does not act on the force applying member 152R (the state shown in Figure 24). The transition from the state in Figure 27 to the state in Figure 24 is performed without delay.

[0300] As described above, in this implementation, when the separation control member 196R moves from the home position to the second position, the separation holding member 151R moves from the separation release position to the separation holding position. Then, when the separation control member 196R returns from the second position to the home position, the developing unit 109 maintains the separated position by the separation holding member 151R. [Detailed explanation of the separation holding member L]

[0301] Here, the separation-holding member 151L will be explained in detail with reference to Figure 28.

[0302] Figure 28(a) is a front view of the separation holding member 151L as seen from the longitudinal direction on the drive side of the process cartridge 100, and Figures 28(b) and 28(c) are perspective views of the separation holding member 151L. The separation holding member 151L has an annular support receiving portion 151La and a separation holding portion 151Lb that protrudes radially from the support receiving portion 151La. The tip of the separation holding portion 151Lb has an arc-shaped separation holding surface 151Lc centered on the pivot axis H of the separation holding member.

[0303] Furthermore, the separation-holding member 151L has a second restricted surface 151Lk adjacent to the separation-holding surface 151Lc. In addition, the separation-holding member 151L has a second pressed portion 151Ld that protrudes in the Z2 direction from the support-receiving portion 151La, and has an arc-shaped second pressed surface 151Le that protrudes from the second pressed portion 151Ld in the direction of the pivot axis H of the separation-holding member of the support-receiving portion 151La.

[0304] Furthermore, the separation-holding member 151L has a main body portion 151Lf connected to the support receiving portion 151La, and the main body portion 151Lf has a spring-hanging portion 151Lg that protrudes in the direction of the pivot axis H of the separation-holding member of the support receiving portion 151La. In addition, the main body portion 151Lf has a rotation-preventing portion 151m that protrudes in the Z2 direction, and a rotation-preventing surface 151Ln is provided in a direction facing the second pressed surface 151Le. [Detailed description of force-applying member L]

[0305] Here, the force-applying member 152L will be explained in detail with reference to Figure 29.

[0306] Figure 29(a) is a front view of the force-applying member 152L as seen from the longitudinal direction of the process cartridge 100, and Figures 29(b) and 29(c) are perspective views of the force-applying member 152L.

[0307] The force-applying member 152L has an elongated oval-shaped support receiving portion 152La. Here, the longitudinal direction of the elongated shape of the elongated support receiving portion 152La is denoted by arrow LH, with arrow LH1 pointing upwards and arrow LH2 pointing downwards. Furthermore, the direction in which the elongated support receiving portion 152La is formed is denoted by HD. The force-applying member 152L has a projection 152Lh formed downstream of the elongated support receiving portion 152La in the direction of arrow LH2. The elongated support receiving portion 152La and the projection 152Lh are connected by the main body portion 152Lb. On the other hand, the force-applying member 152L has a pressed portion 152Le that protrudes in the direction of arrow LH1 and approximately perpendicular to the direction of arrow LH1, and has an arc-shaped pressed surface 152Lf on the downstream side in the direction of arrow LH1, and a pressing restricting surface 152Lg on the upstream side. Furthermore, the force-applying member 152L is part of the oval support receiving portion 152La and has a first storage-restricting surface 152Lv located downstream in the direction of arrow LH2.

[0308] The projection 152Lh has a first force-receiving portion 152Lk and a second force-receiving portion 152Ln, which are located at the end of the LH2 direction and opposite each other in a direction substantially perpendicular to the LH2 direction. The first force-receiving portion 152Lk and the second force-receiving portion 152Ln each have a first force-receiving surface 152Lm and a second force-receiving surface 152Lp, respectively, which extend in the HD direction and have an arc shape. The projection 152Lh also has a spring-hanging portion 152Ls and a locking portion 152Lt that project in the HB direction, and the locking portion 152Lt has a locking surface 152Lu that faces the same direction as the second force-receiving surface 152Lp.

[0309] Furthermore, the force-applying member 152L is part of the main body 152Lb and is positioned upstream of the second force-receiving portion 152Ln in the direction of arrow LH2, and has a first pressing surface 152Lq facing the same direction as the second force-receiving surface 152Lp. Also, the force-applying member 152L is part of the main body 152Lb and is positioned upstream of the first force-receiving portion 152Lk in the direction of arrow LH2, and has a first pressing surface 152Lr facing the same direction as the first force-receiving surface 152Lm.

[0310] Furthermore, when the process cartridge 100 is mounted on the image forming apparatus body 170, the LH1 direction is approximately the same as the Z1 direction, and the LH2 direction is approximately the same as the Z2 direction. Also, the HB direction is approximately the same as the longitudinal direction of the process cartridge 100. [Assembly of the separation contact mechanism L]

[0311] Next, the assembly of the separation mechanism will be explained using Figures 16 and 29 to 35. Figure 30 is a perspective view of the process cartridge 100 after the separation holding member 151L has been assembled, as seen from the drive side. As mentioned above, as shown in Figure 16, the developing unit 109 is fitted with the outer diameter of the cylindrical portion 127a of the non-drive side bearing 127 into the developing unit support hole 117a of the non-drive side cartridge cover member 117. In this way, the developing unit 109 is rotatably supported with respect to the photoreceptor drum 104 around the pivot axis K. The non-drive side bearing 127 also has a cylindrical first support portion 127b and a second support portion 127e that protrude in the direction of the pivot axis K.

[0312] The outer diameter of the first support portion 127b fits with the inner diameter of the support receiving portion 151La of the separation holding member 151L, thereby rotatably supporting the separation holding member 151L. Here, the pivot center of the separation holding member 151L assembled to the non-drive side bearing 127 is defined as the separation holding member pivot axis H. The non-drive side bearing 127 has a first retaining portion 127c that protrudes in the direction of the separation holding member pivot axis H. As shown in Figure 16, the movement of the separation holding member 151L assembled to the non-drive side bearing 127 in the direction of the separation holding member pivot axis H is restricted by the first retaining portion 127c contacting the separation holding member 151L.

[0313] Furthermore, the outer diameter of the second support portion 127e fits with the inner wall of the oval support receiving portion 152La of the force-applying member 152L, supporting the force-applying member 152L so that it can rotate and move in the oval direction. Here, the pivot point of the force-applying member 152L assembled to the non-drive side bearing 127 is defined as the force-applying member pivot axis HC. As shown in Figure 16, the movement of the force-applying member 152L assembled to the non-drive side bearing 127 in the direction of the force-applying member pivot axis HE is restricted by the second retaining portion 127f contacting the separation holding member 151L.

[0314] Figure 31 is a view of the process cartridge 100 after the separation holding member 151L has been assembled, as seen from the direction of the development unit's pivot axis H. This is a cross-sectional view in which a part of the non-drive side cartridge cover member 117 has been partially omitted by the partial cross-sectional line CS so that the fitting portion between the oval support receiving portion 151La of the force-applying member 152L and the cylindrical portion 127e of the non-drive side bearing 127 is visible. Here, the separation contact mechanism 150L is equipped with a tension spring 153 as a biasing means to bias the separation holding member 151L to rotate in the direction of arrow B1 around the pivot axis H of the separation holding member, and to bias the force-applying member 152L in the direction of arrow B3. Note that the direction of arrow B3 is approximately parallel to the longitudinal direction LH2 of the oval support receiving portion 152La of the force-applying member 152L (see Figure 29). The tension spring 153 is assembled between a spring attachment portion 151Lg provided on the separation holding member 151L and a spring attachment portion 152Ls provided on the force applying member 152L. The tension spring 153 applies a force to the spring attachment portion 151Lg of the separation holding member 151Lg in the direction of arrow F2 in Figure 31, thereby providing a biasing force that rotates the separation holding member in the direction of arrow B1. Furthermore, the tension spring 153 applies a force to the spring attachment portion 152Ls of the force applying member 152L in the direction of arrow F1, thereby providing a biasing force that moves the force applying member 152L in the direction of arrow B3.

[0315] Let GS be the line connecting the spring attachment portion 151Lg of the separation-holding member 151L and the spring attachment portion 152Ls of the force-holding member 152L. Let HS be the line connecting the spring attachment portion 152Ls of the force-applying member 152L and the pivot axis HE of the force-applying member. The angle θ3 between line GS and line HE is set to satisfy the following equation (3), with counterclockwise rotation around the spring attachment portion 152Ls of the force-applying member 152L being positive. As a result, the force-applying member 152L is biased to rotate in the direction BA in the figure with the pivot axis HE of the force-applying member as the center of rotation. 0°≦θ3≦90°・・・(3)

[0316] In this embodiment, the mounting positions of the separation holding member 151L and the force applying member 152L are as follows. As shown in Figure 29, in the direction of the pivot axis K, the separation holding member 151L and the force applying member 152L are positioned on the side of the non-drive side bearing 127 where the non-drive side cartridge cover member 117 is located (outer side in the longitudinal direction). However, the position is not limited to this, and they may be positioned on the developing frame body 125 side of the non-drive side bearing 127 (inner side in the longitudinal direction), or the separation holding member 151L and the force applying member 152L may be positioned with the non-drive side bearing 127 in between. Furthermore, the order in which the separation holding member 151L and the force applying member 152L are positioned may be reversed.

[0317] The non-drive bearing 127 is then fixed to the developing frame 125 to form the developing unit 109. In this embodiment, the fixing method is as shown in Figure 16, by fixing screws 145 and an adhesive (not shown), but the fixing method is not limited to this, and other joining methods such as welding by heating or pouring and hardening resin may also be used.

[0318] Here, Figures 32(a) and (b) are cross-sectional views in which the non-drive side cartridge cover member 117, tension spring 153, and a portion of the separation holding member 151L are partially omitted by the partial cross-sectional line CS. For explanatory purposes, Figures 32(a) and (b) are enlarged views of the force-applying member swing axis HE and the area around the separation holding portion 151L of the force-applying member 152L in Figure 31, respectively.

[0319] The force-applying member 152L is positioned by the biasing force of the tension spring 153 in the direction of arrow F1, causing the first restricting surface 152Lv of the force-applying member 152L to contact the second support portion 127e of the non-drive side bearing 127. Also, as shown in Figure 32(b), the first pressing surface 152Lq of the force-applying member 152L contacts the first pressed surface 127h of the non-drive side bearing 127, thereby positioning it. This position is referred to as the storage position (reference position) of the force-applying member 152L. Furthermore, the separation-holding member 151L rotates in the direction of arrow B1 around the pivot axis H of the separation-holding member due to the biasing force of the tension spring 153 in the direction of arrow F2, and is positioned by the contact surface 151Lp of the separation-holding member 151L contacting the second pressing surface 152Lr of the force-applying member 152L. This position is referred to as the separation-holding position (restricting position) of the separation-holding member 151L. Furthermore, when the force-applying member 152L moves to the protruding position described later, the second pressed surface 151Le of the separation-holding member 151L comes into contact with the second pressed surface 152Lr of the force-applying member 152L, thereby allowing it to be positioned in the separation-holding position.

[0320] Furthermore, Figure 33 is an enlarged view of the area around the separation holding part 151L in Figure 31 for illustrative purposes, with the tension spring 153 omitted. Here, we consider the case where the process cartridge 100 having the separation contact mechanism 150L is dropped in the direction of arrow JA in Figure 33 during logistics. At this time, the separation holding member 151L receives a rotational force in the direction of arrow B2 due to its own weight around the separation holding oscillation axis H. For the reasons above, when it starts to rotate in the direction of arrow B2, the rotation prevention surface 151Ln of the separation holding member 151L comes into contact with the locking surface 152L of the force applying member 152L, and the separation holding member 151L receives a force in the direction of arrow F4 to suppress rotation in the direction of arrow B2. This prevents the separation holding member 151L from rotating in the direction of arrow B2 during logistics, and prevents damage to the separated state of the photoreceptor drum 104 and the developing unit 109.

[0321] In this embodiment, a tension spring 153 is given as a biasing means for biasing the separation-holding member 151L to the separation-holding position and the force-applying member 152L to the storage position, but the biasing means is not limited to this. For example, a torsion coil spring, a leaf spring, etc. may be used as a biasing means to bias the force-applying member 152L to the storage position and the separation-holding member 151L to the separation-holding position. Furthermore, the material of the biasing means can be metal, molded metal, or any other material that has elasticity and can bias the separation-holding member 151L and the force-applying member 152L.

[0322] As described above, the developing unit 109 equipped with the separation contact mechanism 150L is integrally coupled with the drum holding unit 108 by the non-driving side cartridge cover member 117 as previously stated (as shown in Figure 30). As shown in Figure 16, the non-driving side cartridge cover 117 in this embodiment has a contact surface 117c. The contact surface 117c is a surface parallel to the pivot axis K. Furthermore, as shown in Figures 16 and 30, when the non-driving side cartridge cover member 117 is assembled to the developing unit 109 and the drum holding unit 108, the contact surface 117c faces the separation holding surface 151Lc of the separation holding member 151L which is located in the separation holding position.

[0323] Here, the process cartridge 100 has a developing pressure spring 134 as a biasing member for bringing the developing roller 106 into contact with the photoreceptor drum 104. The developing pressure spring 134 is assembled between the spring attachment portion 117e of the non-drive side cartridge cover member 117 and the spring attachment portion 127k of the non-drive side bearing 127. The biasing force of the developing pressure spring 134 causes the separation holding surface 151Lc of the separation holding member 151L to come into contact with the contact surface 117c of the non-drive side cartridge cover member 117. When the contact surface 117cc and the separation holding surface 151Lc come into contact, the posture of the developing unit 109 is positioned with a gap P1 between the developing roller 106 of the developing unit 109 and the photoreceptor drum 104. Thus, the state in which the developing roller 106 is separated from the photoreceptor drum 104 by a gap P1 by the separation holding member 151L is called the separated position (retracted position) of the developing unit 109 (see Figure 35(a)).

[0324] Here, the separated and contacting states of the process cartridge 100 will be explained in detail using Figure 35. Figure 35 is a side view from the non-driving side with the process cartridge 100 installed inside the image forming apparatus body 170. Figure 35(a) shows the state in which the developing unit 109 is separated from the photoreceptor drum 104. Figure 35(b) shows the state in which the developing unit 109 is in contact with the photoreceptor drum 104.

[0325] First, with the separation holding member 151L in the separation holding position and the developing unit 109 in the separation position, the pressed portion 152Le of the force-applying member 152L is pressed in the direction of arrow ZA. This causes the protruding portion 152Lh of the force-applying member 152L to protrude from the process cartridge 100 (the state shown in Figure 34(a)). This position is referred to as the protruding position of the force-applying member 152L. As described above, the second pressed surface 151Le of the separation holding member 151L is in contact with the second pressing surface 152Lr of the force-applying member 152L by the tension spring 153. Therefore, when the second force-receiving portion 152Ln is pressed in the direction of arrow W42, the force-applying member 152L rotates in the direction of arrow BD around the force-applying member oscillation axis HE, causing the separation holding member 151L to rotate in the direction of arrow B5. When the separation holding member 151L rotates in the direction of arrow B5, the separation holding surface 151Lc separates from the contact surface 117c, and the developing unit 109 becomes able to rotate from the separated position around the pivot axis K in the direction of arrow V2.

[0326] In other words, the developing unit 109 rotates in the direction of V2 from the separated position, and the developing roller 106 of the developing unit 109 comes into contact with the photoreceptor drum 104. Here, the position of the developing unit 109 where the developing roller 106 and the photoreceptor drum 104 come into contact is called the contact position (developing position) (the state shown in Figure 34(b)). The position where the separated holding surface 151Lc of the separated holding member 151L separates from the contact surface 117c is called the separated release position (allowable position). When the developing unit 109 is in the contact position, the second restricting surface 151Lk of the separated holding member 151L comes into contact with the second restricting surface 117d of the drive-side cartridge cover 116, thereby maintaining the separated holding member 151L in the separated release position.

[0327] Furthermore, the non-driving side bearing 127 in this embodiment has a first pressed surface 127h which is a surface perpendicular to the oscillating axis K. Since the non-driving side bearing 127 is fixed to the developing unit 109, when the developing unit 109 is in the contact position, it presses the first force receiving portion 152Lk of the force applying member 152L in the direction of arrow 41. As a result, the first pressing surface 152Lq comes into contact with the first pressed surface 127h, causing the developing unit 109 to rotate around the oscillating axis K in the direction of arrow V1 and move to the separated position (the state shown in Figure 34(a)). Here, when the developing unit 109 moves from the contact position to the separated position, the direction in which the first pressed surface 127h moves is indicated by arrow W41 in Figures 34(a) and (b). Also, the opposite direction of arrow W41 is arrow W42, and arrows W41 and W42 are in the approximately horizontal direction (X1, X2 direction). As described above, the second force-receiving surface 152Lp of the force-applying member 152L assembled to the developing unit 109 is located upstream of the first pressed surface 127h of the non-driving side bearing 127 in the direction of arrow W41. Furthermore, the first pressed surface 127h and the second force-receiving surface 151Le of the separation-holding member 151L are positioned so that at least a portion of them overlap in the W1 and W2 directions.

[0328] The operation of the separation and contact mechanism 150L within the main body 170 of the image forming apparatus will be described next. [Mounting the process cartridge into the main body of the image forming apparatus]

[0329] Next, using Figures 35 and 36, the engagement operation of the separation contact mechanism 150R of the process cartridge 100 and the development separation control unit 196 of the image forming apparatus body 170 when the process cartridge 100 is mounted on the image forming apparatus body 170 will be explained. Note that for explanatory purposes, these figures are cross-sectional views in which a part of the development cover member 128 and a part of the non-drive side cartridge cover member 117 are partially omitted by partial cross-sectional lines CS. Figure 35 is a view of the process cartridge 100 from the drive side when the process cartridge 100 is mounted on a cartridge tray 171 (not shown) of the image forming apparatus M and the cartridge tray 171 is inserted into the first mounting position. In this figure, only the process cartridge 100, the cartridge pressing unit 121 and the separation control member 196L are shown.

[0330] As previously explained, the image forming apparatus body 170 of this embodiment has a separation control member 196L corresponding to each process cartridge 100, as described above. The separation control member 196L is positioned on the lower side of the image forming apparatus body 170, more so than the separation holding member 151L, when the process cartridge 100 is in the first inner position and the second inner position. The separation control member 196L protrudes toward the process cartridge 100 and has a first force-applying surface 196La and a second force-applying surface 196Lb that face each other via a space 196Rd. The first force-applying surface 196Ra and the second force-applying surface 196Rb are connected via a connecting portion 196Rc on the lower side of the image forming apparatus body 170. The separation control member 196R is rotatably supported on the control plate 197 with respect to a pivot center 196Re. The separation member 196R is always biased in the E1 direction by a biasing spring. Furthermore, since the control sheet metal 197 is configured to be movable in the W41 and W42 directions by a control mechanism (not shown), the separation control member 196R is configured to be movable in the W41 and W42 directions.

[0331] As described above, in conjunction with the transition of the front door 11 of the image forming apparatus body 170 from the open state to the closed state, the cartridge pressing unit 121 descends in the direction of arrow ZA, and the first force-applying part 121a comes into contact with the pressed surface 152Lf of the force-applying member 152L. After the cartridge pressing unit 121 descends to a predetermined position which is the second mounting position, 152Lh of the force-applying member 152L moves to a protruding position that protrudes downward in the Z2 direction of the process cartridge 100 (state shown in Figure 36). Once this operation is complete, as shown in Figure 36, a gap T4 is formed between the first force-applying surface 196La of the separation control member 196L and the first force-receiving surface 152Lp of the force-applying member 152L, and a gap T3 is formed between the second force-applying surface 196Lb and the second force-receiving surface 152Lp. The separation control member 196L is then positioned in the second mounting position where it does not act on the force-applying member 152L. This position of the separation control member 196L is referred to as the home position. At this time, the first force receiving surface 152Lp of the force applying member 152L and the first force applying surface 196La of the separation control member 196L are arranged so that they partially overlap in the W1 and W2 directions. Similarly, the second force receiving surface 152Lp of the force applying member 152L and the second force applying surface 196Lb of the separation control member 196L are arranged so that they partially overlap in the W1 and W2 directions. [Contact operation of the developing unit]

[0332] Next, the operation by which the photoreceptor drum 104 and the developing roller 106 come into contact with each other by the separation contact mechanism 150L will be explained in detail with reference to Figures 36 to 38. Note that these figures are cross-sectional views in which a part of the developing cover member 128, a part of the non-driving side cartridge cover member 117, and a part of the non-driving side bearing 127 are partially omitted by the partial cross-sectional line CS, respectively, for illustrative purposes.

[0333] As explained earlier, the developing input coupling 32 receives a driving force from the image forming apparatus body 170 in the direction of arrow V2 in Figure 24, causing the developing roller 106 to rotate. In other words, the developing unit 109, which has the developing input coupling 32, receives torque from the image forming apparatus body 170 in the direction of arrow V2 around the pivot axis K. Furthermore, the developing unit 109 also receives a biasing force in the direction of arrow V2 due to the biasing force of the developing pressure spring 134 mentioned above.

[0334] As shown in Figure 36, the developing unit 109 is in the separated position and the separated holding member 151L is in the separated holding position when the developing unit 109 receives this torque and the biasing force from the developing pressure spring 134. Even in this case, the separated holding surface 151Lc of the separated holding member 151L contacts the contact surface 117c of the non-drive side cartridge cover member 117, and the posture of the developing unit 109 is maintained in the separated position (state shown in Figure 36).

[0335] In this embodiment, the separation control member 196L is configured to be movable from the home position in the direction of arrow W41 in Figure 36. When the separation control member 196L moves in the direction of W41, the second force-applying surface 196Lb of the separation control member 196L and the second force-receiving surface 152Lp of the force-applying member 152L come into contact, and the force-applying member 152L rotates in the direction of BD with the force-applying member pivot axis HD as the center of rotation. Furthermore, as the force-applying member 152L rotates, the second pressing surface 152Lr of the force-applying member 152L comes into contact with the second pressed surface 151Le of the separation-holding member 151L, causing the separation-holding member 151L to rotate in the direction of B5. The separation-holding member 151L is then rotated by the force-applying member 152L until the separation-release position is reached, where the separation-holding surface 151Lc and the contact surface 117c are separated. Here, the position of the separation control member 196L that moves the separation holding member 151L to the separation release position, as shown in Figure 37, is referred to as the first position.

[0336] In this way, the separation control member 196L moves the separation holding member 151L to the separation release position. Then, the developing unit 109 rotates in the V2 direction due to the torque received from the image forming apparatus body 170 and the biasing force of the developing pressure spring 134, and moves to the contact position where the developing roller 106 and the photoreceptor drum 104 come into contact (state shown in Figure 37). At this time, the separation holding member 151L, which is biased in the direction of arrow B4 by the tension spring 153, is maintained in the separation release position when the second restricted surface 151Lk comes into contact with the second restricted surface 117d of the non-driven cartridge cover member 117. After that, the separation control member 196L moves in the W42 direction and returns to the home position. At this time, the force-applying member 152L rotates in the BC direction by the tension spring 153, and transitions to a state where the first pressing surface 152Lq of the force-applying member 152L and the first pressed surface 127h of the non-driven bearing 127 come into contact (state shown in Figure 38). As a result, the aforementioned gaps T3 and T4 are reformed, and the separation control member 196L is positioned so that it does not act on the force-applying member 152L. The transition from the state shown in Figure 37 to the state shown in Figure 38 occurs without any delay. The position of the separation control member 196L in Figure 38 is the same as in the state shown in Figure 36.

[0337] As described above, in this embodiment, the separation control member 196L moves from the home position to the first position, which rotates the force-applying member 152L and moves the separation holding member 151L from the separation holding position to the separation release position. This allows the developing unit 109 to move from the separation position to the contact position where the developing roller 9 and the photoreceptor drum 104 come into contact. [Separation operation of the developing unit]

[0338] Next, the movement of the developing unit 109 from the contact position to the separated position will be explained in detail using Figures 38 and 39. Note that Figure 39 is a cross-sectional view in which a part of the developing cover member 128, a part of the non-driven cartridge cover member 117, and a part of the non-driven bearing 127 are partially omitted by the partial cross-sectional line CS for illustrative purposes.

[0339] In this embodiment, the separation control member 196L is configured to be movable from the home position in the direction of arrow W42 in Figure 38. When the separation control member 196L moves in the direction of W42, the first force-applying surface 196Lb and the first force-receiving surface 152Lm of the force-applying member 152L come into contact, and the force-applying member 152L rotates in the direction of arrow BC around the force-applying member oscillation axis HD. Since the first pressing surface 152Lq of the force-applying member 152L is in contact with the first pressed surface 127h of the non-drive side bearing 127, the developing unit 109 rotates from the contact position in the direction of arrow V1 around the oscillation axis K (state shown in Figure 39). At this time, the pressed surface 152Lf of the force-applying member 152L has an arc shape, and the center of this arc is positioned to coincide with the oscillation axis K. As a result, when the developing unit 109 moves from the contact position to the separation position, the force received by the cartridge pressing unit 121 on the pressed surface 152Lf of the force applying member 152L is directed in the direction of the oscillation axis K. Therefore, it can be operated in a way that does not hinder the rotation of the developing unit 109 in the direction of arrow V1. The separation holding member 151L separates from the second restricted surface 151Lk of the separation holding member 151L and the second restricted surface 117d of the non-driven cartridge cover member 117, and the separation holding member 151L rotates in the direction of arrow B4 due to the biasing force of the tension spring 153. As a result, the separation holding member 151L rotates until the second pressed surface 151Le of the force applying member 152L comes into contact with the second pressing surface 152LR, and upon contact, moves to the separation holding position. When the developing unit 109 moves from the contact position to the separated position by the separation control member 196L, and the separation holding member 151L is in the separated holding position, a gap T5 is formed between the separated holding surface 151Lc and the contact surface 117c, as shown in Figure 39. Here, the position at which the separation holding member 151 can move to the separated holding position by rotating the developing unit 109 from the contact position to the separated position is referred to as the second position of the separation control member 196L.

[0340] Then, the separation control member 196L moves in the direction of arrow W41, returning from the second position to the home position. As a result, the separation holding member 151L maintains its separation holding position, and the developing unit 109 rotates in the direction of arrow V2 due to the torque received from the image forming apparatus body 170 and the biasing force of the developing pressure spring 134, causing the separation holding surface 151Lc and the contact surface 117c to come into contact. In other words, the developing unit 109 maintains its separated position by the separation holding member 151L, and the developing roller 106 and the photoreceptor drum 104 are separated by a gap P1 (the state shown in Figures 36 and 34(a)). As a result, the aforementioned gaps T3 and T4 are reformed, and the separation control member 196L is positioned so that it does not act on the force applying member 152L (the state shown in Figure 36). The transition from the state in Figure 39 to the state in Figure 36 is performed without any delay.

[0341] As described above, in this embodiment, when the separation control member 196L moves from the home position to the second position, the separation holding member 151L moves from the separation release position to the separation holding position. Then, when the separation control member 196L returns from the second position to the home position, the developing unit 109 maintains the separated position with respect to the separation holding member 151L.

[0342] Up to this point, the operation of the separation mechanism located on the drive side of the process cartridge 100 and the operation of the separation mechanism located on the non-drive side have been described separately, but in this embodiment, they operate in conjunction. That is, when the developing unit 109 is positioned at the separated position by the separation holding member R, this occurs almost simultaneously with the developing unit 109 being positioned at the separated position by the separation holding member L, and the same is true for the contact position. Specifically, the movement of the separation control members 121R and 121L, as described in Figures 23 to 27 and Figures 35 to 39, is performed integrally by a connecting mechanism (not shown). As a result, the timing at which the separation holding member 151R located on the drive side is positioned at the separated holding position and the timing at which the separation holding member 151L located on the non-drive side is positioned at the separated holding position, and the timing at which the separation holding member 151R is positioned at the separated release position and the timing at which the separation holding member 151L is positioned at the separated release position are all approximately simultaneous. These timings may differ between the driving and non-driving sides, but in order to shorten the time from when the user starts a print job until the printed material is ejected, it is desirable that at least the timing of reaching the release position be simultaneous. In this embodiment, the pivot axes H of the separation holding member 151R and the separation holding member 151L are coaxial, but as mentioned above, it is sufficient and not limited to the timing of reaching the release position being approximately simultaneous. Similarly, the pivot axis HC of the force-applying member 152R and the pivot axis HE of the force-applying member 152L are not on the same axis, but as mentioned above, it is sufficient and not limited to the timing of reaching the release position being approximately simultaneous.

[0343] As described above, the drive side and the non-drive side have similar separation contact mechanisms, and they operate almost simultaneously. This allows the amount of separation between the photoreceptor drum 104 and the developing roller 9 to be controlled at both ends in the longitudinal direction, even if the process cartridge 100 is twisted or deformed in the longitudinal direction. Therefore, variations in the amount of separation in the longitudinal direction can be suppressed.

[0344] Furthermore, according to this embodiment, by moving the separation control member 196R(L) between the home position, first position, and second position in one direction (arrows W41 and W42 directions), the contact and separation states of the developing roller 106 and the photoreceptor drum 104 can be controlled. Therefore, the developing roller 106 can be brought into contact with the photoreceptor drum 104 only when image formation is being performed, and the developing roller 4 can be kept separated from the photoreceptor drum 104 when image formation is not being performed. Consequently, even if the device is left unattended for a long period of time without image formation, the developing roller 106 and the photoreceptor drum 104 will not deform, and stable image formation can be achieved.

[0345] Furthermore, according to this embodiment, the force-applying member 152R(L) that acts on the separation-holding member 151R(L) to cause rotational movement can be positioned in the storage position by a biasing force such as the tension spring 153. Therefore, when the process cartridge 100 is located outside the main body of the image forming apparatus 170, it can be miniaturized as a standalone process cartridge 100 without protruding from the outermost shape of the process cartridge 100.

[0346] Similarly, the force-applying member 152R(L) can be positioned in the storage location by a biasing force such as a tension spring 153. Therefore, when mounting the process cartridge 100 to the image forming apparatus body 170, the process cartridge 100 can be mounted by moving it in only one direction. As a result, the process cartridge 100 (tray 171) does not need to be moved in the vertical direction. Consequently, no extra space is required in the image forming apparatus body 170, and the size of the body can be reduced.

[0347] Furthermore, according to this embodiment, when the separation control member 196R(L) is in the home position, no load is applied to the separation control member 196R(L) from the process cartridge 100. Therefore, the rigidity required for the separation control member 196R(L) and the mechanism that operates the separation control member 196R(L) can be reduced, and the device can be miniaturized. In addition, the load on the sliding part of the mechanism that operates the separation control member 196R(L) is also reduced, which can suppress wear on the sliding part and the generation of abnormal noise.

[0348] Furthermore, according to this embodiment, the developing unit 109 can maintain its separated position solely by the separation holding member 151R(L) of the process cartridge 100. Therefore, by reducing the number of parts that cause variations in the separation amount between the developing roller 106 and the photoreceptor drum 104, the part tolerance can be reduced, and the separation amount can be minimized. Because the separation amount can be reduced, when the process cartridge 100 is placed inside the image forming apparatus body 170, the area occupied by the developing unit 109 when it moves to the contact position and the separated position is reduced, thereby enabling miniaturization of the image forming apparatus. In addition, the space for the developer storage section 29 of the developing unit 109 when it moves to the contact position and the separated position can be increased, so a miniaturized and high-capacity process cartridge 100 can be placed inside the image forming apparatus body 170.

[0349] Furthermore, according to this embodiment, the force-applying member 152R(L) can be positioned in the storage position when the process cartridge 100 is installed, and the developing unit 109 can maintain its separated position solely by the separation-holding member 151R(L) of the process cartridge 100. Therefore, when installing the process cartridge 100 into the image forming apparatus body 170, the installation can be completed by moving the process cartridge 100 in only one direction. Therefore, it is not necessary to move the process cartridge 100 (tray 171) in the vertical direction. Consequently, no extra space is required in the image forming apparatus body 170, and the size of the body can be reduced. In addition, because the amount of separation can be reduced, when the process cartridge 100 is placed inside the image forming apparatus body 170, the area occupied by the developing unit 109 when it moves to the contact position and the separated position is reduced, thereby enabling miniaturization of the image forming apparatus. In addition, the space for the developer storage section 29 of the developing unit 109, which moves to the contact and separation positions, can be increased, allowing a smaller, high-capacity process cartridge 100 to be placed in the image forming apparatus body 170. [Details of the arrangement of the separation contact mechanism]

[0350] Next, the arrangement of the separation and contact mechanisms R and L in this embodiment will be explained in detail using Figures 40 and 41.

[0351] Figure 40 is an enlarged view of the area around the separation holding member 151R of the process cartridge 100, as seen from the drive side along the oscillation axis K (photoreceptor drum axis direction) of the developing unit 109. In addition, for explanatory purposes, a portion of the developing cover member 128 and a portion of the drive-side cartridge cover member 116 are partially omitted by the partial cross-sectional line CS. Figure 41 is an enlarged view of the area around the separation holding member 151R of the process cartridge 100, as seen from the non-drive side along the oscillation axis K (along the axis in the photoreceptor drum axis direction) of the developing unit 109. In addition, for explanatory purposes, a portion of the developing cover member 128 and a portion of the drive-side cartridge cover member 116 are partially omitted by the partial cross-sectional line CS. Regarding the arrangement of the separation holding member and force-applying member described below, except for the parts that will be explained in detail later, there is no distinction between the drive side and the non-drive side and they are the same, so the explanation will be given only for the drive side, and the same applies to the non-drive side.

[0352] As shown in Figure 40, the rotation center of the photoreceptor drum 104 is defined as point M1, the rotation center of the developing roller 106 is defined as point M2, and the line passing through points M1 and M2 is defined as line N. Furthermore, the contact area between the separation holding surface 151Rc of the separation holding member 151R and the contact surface 116c of the drive-side cartridge cover member 116 is defined as M3, and the contact area between the second pressed surface 151Re of the separation holding member 151R and the second pressing surface 152Rr of the force-applying member 152R is defined as M4. In addition, the distance between the pivot axis K of the developing unit 109 and point M2 is defined as distance e1, the distance between the pivot axis K and region M3 is defined as distance e2, and the distance between the pivot axis K and point M4 is defined as distance e3.

[0353] In this embodiment, when the developing unit 109 is in the separated position and the force-applying member 152R(L) is in the protruding position, the positional relationship is as follows. That is, when viewed along the axial direction of the oscillation axis K shown in Figure 40 (axial direction of the photoreceptor drum), at least a portion of the contact area M3 between the separation holding member 151R and the drive-side cartridge cover member is located in the area opposite to the area where the center of the developing coupling 32 (oscillating axis K) is located, with a line N passing through the center of the photoreceptor drum 104 and the center of the developing roller 106. In other words, the separation holding surface 151Rc of the separation holding member 151R is positioned such that the distance e2 is longer than the distance e1.

[0354] By arranging the separation-holding member 151R and the separation-holding surface 151Rc in this manner, variations in the orientation of the separation position of the developing unit 109 can be kept to a minimum when the position of the separation-holding surface 151Rc varies due to part tolerances, etc. In other words, the influence of variations in the separation-holding surface 151Rc on the separation amount (gap) P1 between the developing roller 106 and the photoreceptor drum 104 (see Figure 42(a)) can be minimized, allowing the developing roller 106 and the photoreceptor drum 104 to be separated with high precision. Furthermore, there is no need to have extra space for the developing unit 109 to retract when it separates, which leads to miniaturization of the image forming apparatus body 170.

[0355] Furthermore, the first force-receiving portion 152Rk(Lk) and the second force-receiving portion 152Rn(Ln), which are the force-receiving portions of the force-applying member 152R(L), are positioned on the opposite side of the rotation center of the developing coupling 32, with the extension of line N in between.

[0356] As explained above, the force receiving parts 152Rk(Lk) and 152Rn(Ln) are located at the longitudinal ends. Also, as shown in Figure 15 (Figure 16), the cylindrical part 128b(127a), which is the support part for the developing unit 109, is located at the longitudinal ends. Therefore, by arranging the force receiving parts 152Rk(Lk) and 152Rn(Ln) on the opposite side of line N from the cylindrical part 128b(127a) (i.e., the pivot axis K) of the developing unit 109, the functional parts can be efficiently arranged. In other words, this leads to miniaturization of the process cartridge 100 and the image forming apparatus M.

[0357] In addition, the force receiving parts 152Rk and 152Rn are located at the longitudinal drive-side end. Furthermore, as shown in Figure 15, a developing drive input gear 132 is provided at the longitudinal drive-side end, which receives power from the image forming apparatus body 170 and drives the developing roller 106. As shown in Figure 40, the force applying members 152Rk and 152Rn are located on the opposite side of the rotation center K of the developing drive input gear 132 (developing coupling part 132a), shown by the dashed line, across the extension of line N. This arrangement allows for efficient placement of the functional parts. In other words, it leads to miniaturization of the process cartridge 100 and the image forming apparatus M.

[0358] Furthermore, the contact area between the separation-holding member 151R and the force-applying member 152R is arranged such that the distance e3 is longer than the distance e1. This allows the separation-holding member 151R and the drive-side cartridge cover member 116 to be brought into contact with less force. In other words, it becomes possible to stably separate the developing roller 106 and the photoreceptor drum 104. [Detailed explanation of the drive transmission mechanism to the photoreceptor drum]

[0359] The following describes the configuration for transmitting driving force from the main body of the image forming apparatus to the drum unit 103 of the cartridge 100 (see Figure 1(a)) and driving (rotating) the drum unit 103.

[0360] The drum unit 103 shown in Figures 1, 13, and 55 to 58 is a unit having a photoreceptor drum, a drum coupling (cartridge-side coupling, coupling member) 143, and a drum flange 142 (see Figure 13). The drum unit 103 is detachable from the image forming apparatus body as part of the cartridge 100. The drum unit 103 is configured to be connected to a drive transmission unit 203 (see Figures 43 and 44; details will be described later) provided on the apparatus body when mounted on the apparatus body. The drum unit 103 rotates in the direction of arrow A during image formation (see Figures 1, 55 to 57). In this embodiment, when looking at the drive side of the drum unit 103 (the side with the drum coupling 143), that is, when looking at the drum unit 103 along the direction of arrow M1B, the rotation direction of the drum unit 103 corresponds to clockwise (see Figure 1). In other words, when looking at the front of the drum coupling 143, the rotation direction A of the drum coupling 143 corresponds to clockwise.

[0361] The rotation direction A of the drum unit (drum coupling 143 and photoreceptor drum 104) can be explained using the movement of the surface of the photoreceptor drum 104 as follows (see Figures 2 and 3). Note that in Figures 2 and 3, unlike Figure 1, the cartridge is viewed from the non-driven side, so the rotation direction A of the drum unit 103 is counterclockwise.

[0362] As shown in Figure 3, the surface of the photoreceptor drum 104 is charged inside the cartridge near the charging roller 105 (around the position where it contacts the charging roller). Subsequently, the surface of the photoreceptor drum 104 moves to a position where it receives laser light U, and an electrostatic latent image is formed on its surface. Further on, the surface of the photoreceptor drum 104 moves to a position near the developing roller 106 (in this embodiment, a position where it contacts the developing roller), and the latent image formed on the surface of the photoreceptor drum 104 is developed as a toner image. After that, the surface of the photoreceptor drum 104 moves to a position below the cartridge and exposed to the outside of the cartridge casing. Then, as shown in Figure 2, the surface of the photoreceptor drum 104 exposed from the cartridge casing comes into contact with the intermediate transfer belt 12a provided in the image forming apparatus body. As a result, the toner image is transferred from the surface of the photoreceptor drum 104 to the transfer belt 12a. After that, the surface of the photoreceptor drum 104 returns to the inside of the cartridge and moves to a position near the charging roller 105.

[0363] In summary, when the coupling 143 receives a driving force and the photoreceptor drum 104 rotates, the surface of the photoreceptor drum 104 moves from a position close to the charging roller 105 to a position close to the developing roller 106. After that, the surface of the photoreceptor drum 104 is exposed to the outside of the cartridge casing, and then returns to the inside of the cartridge casing, once again coming close to the charging roller 105.

[0364] As described above, the cartridge 100 in this embodiment does not have a cleaning means for contacting the photoreceptor drum 104 to remove toner from the surface of the photoreceptor drum 104 (see Figure 3). Therefore, the torque required to rotate the drum unit 103 (photoreceptor drum 104) inside the cartridge 100 is relatively small. In such a configuration, the drum unit 103 is easily affected by its surroundings when it is driven, and as a result, the drum unit 103 may be affected by external influences, potentially causing its rotation speed to become unstable. For example, in this embodiment, the developing roller 106, the charging roller 105, and the transfer belt 12a are in contact with the photoreceptor drum 104. If there are fluctuations in the magnitude of the frictional force generated between these and the photoreceptor drum 104, the speed of the drum unit 103 may fluctuate.

[0365] Therefore, in this embodiment, the drum drive coupling 180 of the drive transmission unit 203 (see Figure 43) provided on the main body of the device is configured to require a certain amount of torque when rotating the drum unit 103 (photoreceptor drum 104) of the cartridge. As a result, the rotation of the drum unit 103 becomes less susceptible to external influences, and its rotational speed becomes stable.

[0366] First, the drum coupling 143 of the process cartridge 100 will be explained using Figure 1(a). Figure 1(a) is a perspective view of the drum coupling.

[0367] The drum coupling 143 in this embodiment is manufactured by injection molding of polyacetal resin. The material may be a resin material such as polycarbonate resin or polybutylene terephthalate resin, or a resin material compounded with glass fiber, carbon fiber, etc. Alternatively, a metal material such as aluminum, iron, or stainless steel may be used, and processing methods such as die casting or cutting may be employed.

[0368] Next, the shape of the drum coupling 143 will be explained using Figures 1, 55 to 58.

[0369] In the following description of the drum coupling 143, the direction from the photoreceptor drum 104 toward the drive transmission unit 230 (drum drive coupling 180) along the axial direction (direction of arrow M1A) is referred to as the outward direction in the axial direction. The direction opposite to the outward direction (direction of arrow M1B) is referred to as the inward direction in the axial direction.

[0370] In other words, in a drum coupling, the outward direction in the axial direction (M1A direction) is the direction from the non-driven end 104b of the photoreceptor drum 104 toward the driven end 104a (leftward in Figure 80). Alternatively, the outward direction in the axial direction (M1A direction) is the direction from the non-driven cartridge cover 117 of the cartridge 100 toward the driven cartridge cover 116 in Figure 14.

[0371] Inward axial direction (M1B direction) refers to the direction from the drive-side end 104a of the photoreceptor drum 104 toward the non-drive-side end 104b (rightward in Figure 80). Alternatively, inward axial direction (M1B direction) refers to the direction from the drive-side cartridge cover 116 of the cartridge 100 toward the non-drive-side cartridge cover 117 in Figure 14.

[0372] As shown in Figure 1(b), the drum coupling 143 is attached to one longitudinal end (drive-side end) of the photoreceptor drum 104. As previously explained, the shaft portion 143j shown in Figure 1 is rotatably supported by the drive-side cartridge cover member 116 (see Figure 15) that supports the photoreceptor drum unit 103. The drum unit 103 is configured to rotate in a predetermined rotational direction (direction of arrow A) when developing an image in which the latent image on the surface of the photoreceptor drum is developed.

[0373] The drum coupling 143 is configured to receive a driving force from the main drive transmission unit 203 of the device body to rotate the photoreceptor drum 104, and also to receive a braking force to apply a load to the rotation of the photoreceptor drum 104.

[0374] The drum coupling 143 has a projection that protrudes outward in the axial direction from the end surface of the shaft portion 143j (see Figures 1, 52 to 57). This projection has a drive force receiving portion 143b, which serves as the first side surface (first side portion) for receiving drive force from the drive transmission unit 203. The projection of the drum coupling 143 also has a brake force receiving portion 143c, which serves as the second side surface (second side portion) for receiving brake force from the drive transmission unit 203.

[0375] The driving force receiving portion 143b is the side surface (side portion) facing the upstream side in the rotation direction A of the drum unit. The braking force receiving portion 143c is the side surface (side portion) facing the downstream side in the rotation direction A.

[0376] In other words, one of the drive force receiving portion 143b and the brake force receiving portion 143c faces one side of the drum unit in the circumferential direction, and the other faces the other side in the circumferential direction. That is, the drive force receiving portion 143b and the brake force receiving portion 143c are sides (sides) that face each other in opposite directions in the rotational and circumferential directions.

[0377] Furthermore, the projection of the drum coupling 143 has a helical slope (inclined portion, ramp) 143d as its top surface (upper surface, upper side portion, upper part). The slope (top surface) 143d is the portion that faces outward in the axial direction (direction of arrow MA1). In other words, the slope 143d is the portion that faces away from the non-driven end of the drum unit (i.e., the end on which the drum flange 142 (Figure 13) is located). To put it another way, the helical slope (top surface) 143d of the coupling 143 is the portion that faces away from the side on which the photoreceptor drum 104 is located.

[0378] The helical inclined surface 143d is tilted outward in the axial direction (in the direction of arrow MA1) as it moves upstream in the direction of rotation (upstream in the direction of arrow A). In other words, as it moves upstream in the direction of rotation, the inclined surface 143d moves away from the non-driven side of the drum unit 103. To put it another way, as it moves upstream in the direction of rotation, the inclined surface 143d is tilted away from the photosensitive drum.

[0379] To put it another way, the helical inclination 143d extends so that it approaches the non-driven end of the drum unit 103 and the cartridge as it moves from upstream to downstream in the direction of rotation. To put it another way, if you measure the distance of the helical inclination 143d from the non-driven end of the cartridge along the axial direction, that distance becomes shorter as you move downstream in the direction of rotation.

[0380] The helical inclined surface 143d has a downstream portion (downstream top surface, downstream inclined surface, downstream inclined portion, downstream guide) 143d1 sandwiched between the drive force receiving portion 143b and the brake force receiving portion 143c in the rotational direction of the drum unit. The inclined surface 143d also has an upstream portion (upstream top surface, upstream inclined surface, upstream inclined portion, upstream guide) 143d2. The upstream portion 143d2 of the helical inclined surface 143d is located upstream in the rotational direction from the drive force receiving portion 143b and the downstream portion 143d1 of the helical inclined surface 143d (see Figures 55-58).

[0381] Furthermore, when measuring the length of the slope 143d along the rotation direction of the drum unit, the length of the upstream slope 143d2 is greater than the length of the downstream slope 143d1.

[0382] The upstream portion of the inclined surface 143d (upstream inclined surface) 143d2 is positioned radially inward (closer to the axis L) than the driving force receiving portion 143b. In other words, the upstream portion of the inclined surface 143d (upstream top surface, upstream inclined surface) 143d2 is positioned closer to the axis L (Figure 1(a)) than the driving force receiving portion 143b. The axis L (Figure 1(a)) is the axis (rotation axis) that serves as the rotation center of the coupling 143 and the photoreceptor drum 104.

[0383] Furthermore, the projection of the drum coupling 143 is provided with a circular hole portion 143a, which serves as an opening for engaging with the positioning boss (positioning part) 180i of the drum drive coupling 180 to position their respective axes. The circular hole portion 143a is an opening with a circular cross-sectional shape perpendicular to the axis L of the drum coupling 143, and is positioned along the axis L.

[0384] The projection of the drum coupling 143 has a shaft portion 143p (see Figure 1) formed along the axis L (see Figure 1(a)), and a circular hole portion 143a is formed inside the shaft portion 143p. The shaft portion 143p is the shaft portion for forming the circular hole portion 143a.

[0385] The shaft portion 143p and the circular hole portion 143a are positioned on the axis L. The formation of the circular hole portion 143a creates an open space between the rotation axis L of the drum unit (see Figure 1(a)) and the inner surface of the drum coupling 143. Note that the shaft portion 143p has a smaller diameter than the aforementioned shaft portion 143j.

[0386] The drum coupling 143 described above has an axisymmetric shape with respect to the axis L (see Figure 1(a)). The driving force receiving portion 143b, the braking force receiving portion 143c, and the helical inclined surface 143d are each arranged in two locations so as to be 180° apart in the circumferential direction, forming the first coupling portion 143r and the second coupling portion 143s (see Figure 58), respectively.

[0387] Each coupling section has one driving force receiving section 143b, one braking force receiving section 143c, and one helical inclined surface 143d, and the first coupling section 143r and the second coupling section 143s are arranged symmetrically with respect to the axis.

[0388] The driving force receiving portion 143b, the braking force receiving portion 143c, and the helical inclined surface 143d are arranged around the aforementioned circular hole portion 143a and the shaft portion 143p. The driving force receiving portion 143b, the braking force receiving portion 143c, and the helical inclined surface 143d are located further away from the axis L of the drum unit than the circular hole portion 143a and the shaft portion 143p.

[0389] Next, the configuration of the main body drive transmission unit 203 provided on the main body side of the device will be described using Figures 43, 44, and 59. The drive transmission unit 203 is a unit that connects (engages) with the drum coupling 143 to rotate the drum coupling 143.

[0390] Figure 43 is an exploded perspective view of the main body drive transmission unit 203. Figure 59 is an enlarged perspective view of a part of Figure 43. Figure 44 is a cross-sectional view of the main body drive transmission unit 203.

[0391] The drive gear 201 is rotatably supported on a support shaft 202 fixed to the frame (not shown) of the device body 170, and rotates when driving force is transmitted from a motor (not shown). The drum drive coupling 180 has a cylindrical portion 180c and a flange portion 180a provided at its end, and the flange is fitted into and supported by the fitting portion 201a of the drive gear 201. In addition, the drum drive coupling 180 is provided with a rotation stopper portion 180b extending from the flange portion 180a, and receives the driving force when the drive gear 201 rotates by contacting the rotation stopper portion 201b of the drive gear 201. The drive transmission unit 203 has multiple components inside the cylindrical portion 180c of the drum drive coupling 180.

[0392] The components located inside the cylindrical portion 180c include: a brake member 206 supported and prevented from rotating by the support shaft 202; a brake transmission member 207 connected to the brake member 206 to transmit braking force; first and second brake engagement members 204 and 208 that engage with the brake force receiving surface 143c of the drum coupling 143; and a brake engagement spring 211 and a drum drive coupling spring 210 arranged along the axis M1 and generating a biasing force in the direction of the axis M1 (axial direction). The axis M1 is the rotation axis of the main body side drive transmission unit 203.

[0393] The shapes of each component located inside the main drive transmission unit 203 will now be described. The first brake engagement member 204 is formed from a cylindrical portion 204d, a flange portion 204a, and a coupling engagement portion 204b that protrudes in a claw shape and engages with the drum coupling 143. A part of the cylindrical portion has a rotation-stopping recess 204c that engages with the rotation-stopping projection 208c of the second brake engagement member 208, which will be described later.

[0394] The second brake engagement member 208 is provided with a flange portion 208a, a coupling engagement portion 208b that protrudes in a claw shape and engages with the drum coupling 143, and a rotation-stopping projection 208c that engages with the rotation-stopping recess 204c of the first brake engagement member 204. Since the rotation of the second brake engagement member 208 is stopped relative to the first brake engagement member 204, the first and second brake engagement members 204 and 208 rotate together as a single unit. Furthermore, the first and second brake engagement members 204 and 208 are connected so that they move together as a single unit in the axial direction.

[0395] Therefore, the first and second brake engagement members 204 and 208 are sometimes collectively referred to simply as brake engagement members (204, 208).

[0396] The first brake engaging member 204 is an outer brake engaging member positioned radially outward, and the second brake engaging member 208 is an inner brake engaging member positioned radially inward.

[0397] The brake transmission member 207 consists of a flange portion 207a and a shaft portion 207b. The flange portion 207a is provided with a projection 207e that engages with a protrusion 204e provided on the flange portion 204a of the first brake engagement member 204. The flange portion 207a of the brake transmission member 207 is positioned between the flange portion 204a of the first brake engagement member 204 and the flange portion 208a of the second brake engagement member 208, and is sandwiched between them with axial play (gap) G (Figure 44). In the axial direction M1A, when the brake transmission member 207 is in a position relative to the first brake engagement member 204 in which the projection 207e (see Figures 43 and 59) engages with the protrusion 204e, the brake transmission member 207 and the first and second brake engagement members 204 and 208 rotate integrally. On the other hand, when the brake transmission member 207 is in a position relative to the first brake engagement member 204 in the axial direction such that the projection 207e does not engage with the convex portion 204e, the brake transmission member 207 does not restrict the rotation of the first and second brake engagement members 204 and 208. The first and second brake engagement members 204 and 208 are rotatable relative to the brake transmission member 207. The shaft portion 207b has a non-circular cross-section and engages with the engagement hole 206c of the brake member 206, which will be described later, to allow the brake transmission member 207 and the brake member 206 to rotate together.

[0398] The brake member 206 is divided into a fixed side 206a and a rotating side 206b, but they are integrated in the axial direction by a retaining mechanism (not shown). The fixed side 206a is supported by the support shaft 202, and its rotation around the shaft is also fixed. On the other hand, the rotating side 206b is rotatable around the support shaft 202, but rotates while receiving a braking force (load) in the rotational direction from the fixed side 206a. The method of generating the braking force can be appropriately selected, such as friction or viscosity.

[0399] As described above, the brake engagement members (204, 208) are connected to the brake member 206 via the brake transmission member 207. Therefore, the rotational torque of the brake engagement members (204, 208) increases due to the load (braking force) generated by the brake member 206. The brake engagement spring 211 is a compression coil spring and is positioned to be compressed between the end face 206d of the brake member 206 and the flange portion 204a of the first brake engagement member 204. As a result, the spring 211 provides a repulsive force (biasing force, elastic force) to both the end face 206d of the brake member 206 and the flange portion 204a of the first brake engagement member 204.

[0400] The drum drive coupling spring 210 is a compression coil spring and is positioned to be compressed between the end face 206d of the brake member 206 and the flange portion 207a of the brake transmission member 207. As a result, the spring 210 provides a repulsive force (biasing force, elastic force) to both the end face 206d of the brake member 206 and the flange portion 207a of the brake transmission member 207.

[0401] The brake transmission member 207 receives the repulsive force of the brake engagement spring 211 via the flange 204a of the first brake engagement member 204, while also directly receiving the repulsive force of the drum drive coupling spring 210. The projection 207f at the axial M1A end of the brake transmission member 207 abuts against the abutment surface 180f of the drum drive coupling 180 (see Figure 44).

[0402] As a result, the drum drive coupling 180 also receives the force of the drum drive coupling spring 210 and the brake engagement spring 211 via the brake transmission member 207. The drum drive coupling 180 attempts to move due to the force of the springs 210 and 211. Therefore, the movement of the drum drive coupling 180 in the direction of arrow M1B is restricted (limited) by the axial direction restricting part 212 (see Figure 44) to prevent the drum drive coupling 180 from detaching from the main body drive transmission unit 203. Specifically, when the drum drive coupling 180 moves a certain distance to the direction of arrow M1B, the flange portion 180a of the drum drive coupling 180 (see Figure 43) comes into contact with the restricting part 212 (see Figure 44). This prevents the drum drive coupling 180 from moving or detaching.

[0403] Furthermore, in this state, if the drum drive coupling 180 receives a force from the outside in the direction of arrow M1A, it can move in the direction of arrow M1A while compressing the springs 210 and 211.

[0404] Furthermore, when the brake engaging members (204, 208) engage with the coupling 143, the coupling engaging portions 204b and 208b may interfere with the coupling 143 (see Figure 60; details will be described later). In that case, the brake engaging members (204, 208) can move into the back of the drive transmission unit 203 (retract) while compressing the springs 210 and 211 in the direction of arrow M1A (see Figure 61).

[0405] As described above, the brake engagement members (204, 208) are positioned with a gap G between them and the brake transmission member 207 (see Figure 44). Within the width of this gap G, the brake engagement members (204, 208) can move and retract relative to the brake transmission member 207 in the direction M1A. Similarly, the brake engagement members (204, 208) can move relative to the drum drive coupling 180 in the direction of arrow M1A within the width of the gap G. When the brake engagement members (204, 208) move relative to the brake transmission member 207 and the drum drive coupling 180 in the direction of arrow M1A, the brake engagement spring 211 is compressed.

[0406] Furthermore, when the brake engaging members (204, 208) move beyond the width of the gap G and come into contact with the brake transmission member 207 which is attempting to move in the direction of arrow M1A, the brake transmission member 207 also moves in the direction of arrow M1A together with the brake engaging members (204, 208).

[0407] Along with the brake engagement members (204, 208), the drum drive coupling 180 also moves in the direction of arrow M1A. As shown in Figure 62, the drum drive coupling 180 and the first brake engagement member 204 each have a protruding engagement portion 180u and an engagement portion 204u, respectively. Therefore, when the brake engagement member 204 moves beyond a certain distance relative to the drum drive coupling 180 in the direction of arrow M1A, the engagement portion 204u pushes the engagement portion 180u, causing the drive coupling 180 to retract in the direction of M1A. At this time, not only the spring 211 but also the spring 210 is compressed.

[0408] When the brake engaging members (204, 208) move in the direction of arrow M1A relative to the brake transmission member 207, the engagement between the projection 207e of the brake transmission member 207 and the convex portion 204e of the first brake engaging member 204 is released. In other words, the brake engaging members (204, 208) lose their connection with the brake transmission member 207 and are no longer subjected to braking force from the brake transmission member 207. The brake members (204, 208) can rotate relative to the brake transmission member 207 without being subjected to the rotational load generated by the brake member 206.

[0409] In other words, by retracting in the direction of arrow M1A, the brake engaging members (204, 208) can move from a position where they receive a rotational load (braking force) from the brake member 206 during rotation to a position where they do not receive this rotational load during rotation. The brake engaging members (204, 208) are configured to reduce their own torque by moving in the direction of M1A relative to the brake transmission member 207 and the drum drive coupling 180.

[0410] Figure 45 is a perspective view showing the positional relationship between the drum drive coupling 180 and the brake engagement members (204, 208). Figure 45(a) is a perspective view of only the drum drive coupling 180, and Figure 45(b) is a perspective view showing both the drum drive coupling 180 and the brake engagement members (204, 208) in place. Figures 45(c) and (d) show the drum drive coupling 180 with the reinforcing cylindrical portion 180e omitted (invisible) for illustrative purposes. The phase of the brake engagement members (204, 208) differs between Figures 45(c) and (d).

[0411] As shown in Figure 45(a), the drum drive coupling (driving force applying member) 180 has two drive transmission surfaces 180d that engage with the coupling 143 to transmit driving force (driving force applying portion), separated by 180 degrees in the circumferential direction. The drum drive coupling has an axisymmetric shape.

[0412] A through hole 180f is provided in the portion other than the drive transmission surface 180d, communicating in the direction of the axis M1. The coupling engagement portions 204b and 208b of the first brake engagement member 204 and the second brake engagement member 208 are exposed through this through hole 180f in a direction facing the coupling 143 (see Figure 60).

[0413] Figure 45(b) shows the coupling engagement portions 204b and 208b of the first brake engagement member 204 and the second brake engagement member 208 in an exposed state. The drum drive coupling 180 is provided with a reinforcing cylindrical portion 180e to increase the rigidity of the drive transmission surface 180d. Figure 45(c) shows a diagram in which the reinforcing cylindrical portion 180e is not shown for illustrative purposes. Figure 45(c) shows a state in which the coupling engagement portions 204b and 208b and the drive transmission surface 180d are in a phase relationship that is close in the rotational direction A. The size of the through hole 180f is set to be wider than the width of the coupling engagement portions 204b and 208b in the circumferential direction. Therefore, the coupling engagement portions 204b and 208b can move within a certain range in the rotational direction within the drum drive coupling 180.

[0414] Figure 45(d) shows a state in which the coupling engagement portions 204b and 208b and the drive transmission surface 180d are in a phase relationship that is separated in the rotational direction A.

[0415] Next, the method of connecting the drive transmission unit 203 on the main body side of the drive transmission mechanism and the photoreceptor coupling 143 on the process cartridge 100 side will be explained using Figures 1 and 43 to 51. [Coupling engagement operation]

[0416] Next, we will explain the process of connecting the drum drive coupling 180 on the main body side of the image forming apparatus main body 170 with the drum coupling 143 of the process cartridge 100.

[0417] Figure 46 shows a cross-sectional view of the area around the drum drive coupling 180 on the main body side of the image forming apparatus main body 170. Using Figure 46, we will explain the general movement of the drum drive coupling 180 on the main body side.

[0418] When a user opens the front door 111 (Figure 4) of the image forming apparatus body 170 to replace the process cartridge 100, the drive transmission unit 203 is moved along axis M1 in the direction of arrow M1A by a link mechanism (not shown) connected to the front door 111. In other words, the drive transmission unit 203 moves away from the process cartridge 100 and the drum coupling 143 (see Figure 60).

[0419] When the user installs the process cartridge 100 and closes the front door 111, the action of the aforementioned link is eliminated. As a result, the drum drive coupling 180, brake engagement members 204 and 208, and brake transmission member 207 attempt to move again in the direction of arrow M1B due to the biasing force of the drum drive coupling spring 210 and the brake engagement spring 211. At this time, the drum coupling 143 of the process cartridge 100 is waiting in the direction of arrow M1B and interferes with the approaching drive transmission unit 203 (as shown in Figures 61, 65, and 69). The drum coupling 143 and the drive transmission unit 203 end up pushing against each other.

[0420] In these states, the drum coupling 143 and the drum drive coupling 180 of the drive transmission unit 203 are normally not engaged.

[0421] For the drum coupling 143 and the main body drum drive coupling 180 to be properly engaged, the drive transmission unit 203 needs to rotate further from the aforementioned pushing state. In other words, the drive transmission unit 203 needs to proceed through its drive process until the main body drum drive coupling 180 engages with the drum coupling 143.

[0422] Furthermore, the process until engagement is complete can be divided into several cases depending on the phase between the drum coupling 143 and the main body drum drive coupling 180, so these will be explained separately.

[0423] Figure 47(a) shows the drum coupling 143 and Figure 47(b) shows the drive transmission unit 203, both viewed from the axial direction. Figure 47(a) will be used to further explain the shape of the coupling 143. The coupling has different shapes arranged in the radial direction. The following configuration is arranged within the radius indicated by R1 in the figure.

[0424] In other words, a positioning hole (opening) 143a that engages with the positioning boss (positioning part) 180i of the drive coupling 180, an overhang (overhang part) 143g (see Figures 47(a) and 1) that prevents the drive transmission unit 203 from entering in the axial direction, and a part of the helical slope 143d are arranged. Within the range indicated by R1 to R2, a part of the helical slope 143d and a part of the brake force receiving surface 143c are arranged. The brake force receiving surface 143c is not visible from the line of sight in Figure 47(a) and is shown in Figure 1. Within the range indicated by R2 to R3, the drive force receiving part 143b, a part of the helical slope 143d, and a part of the brake force receiving surface 143c are arranged.

[0425] On the other hand, the drive transmission unit 203 also has shapes with different functions arranged radially, so the same range as the coupling 143 is shown in Figure 47(b) using the same symbols R1 to R3.

[0426] Within the radius range indicated by R1 in Figure 47(b), a positioning boss 180i that engages with the positioning hole 143a of the drum coupling 143 and an inward projection 208e, which is part of the coupling engagement portion 208b of the second brake engagement member 208 and contacts the visor 143g depending on the phase with respect to the drum coupling 143, are arranged. Within the range indicated by R1 to R2, the coupling engagement portion 208b of the second brake engagement member 208 is arranged. Within the range indicated by R2 to R3, the drive transmission surface 180d and the first brake engagement member 204 are arranged.

[0427] Figure 48 is an exploded view of these parts unfolded around the rotation axis M1. Figure 48 explains the process until the drum coupling 143 and the drive transmission unit 203 engage.

[0428] Figure 48 shows the drive transmission unit 203 at the bottom, illustrating the process of it moving in the direction of arrow M1B, approaching the drum coupling 143, and completing the engagement. In this figure, structures located within the radius R1 shown in Figure 47 are shown with dashed lines, structures located between the radius R1 and R2 are shown with solid lines, and structures located between R2 and R3 are shown with solid lines and hatching.

[0429] The drum coupling 143 has two coupling sections 143s and 143r arranged 180° apart, but for the sake of simplicity, only coupling section 143s will be described below. The description of coupling section 143s also applies to coupling section 143r.

[0430] Figure 48(a) shows the state in which the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are in close proximity. As shown in Figure 48(a), the relative phases of the inclination start portion 143f of the drum coupling 143 and the inward projection 208e of the second brake engagement member 208 are in the following relationship. That is, the inclination start portion 143f of the drum coupling 143 is upstream of the projection 208e in the rotational direction (arrow A).

[0431] Figure 48(b) shows the state after the drive transmission unit 203 has moved further in the direction of arrow M1B from the state shown in Figure 48(a). The helical inclined surface 143d is in contact with the inward projection 208e of the approaching first brake engagement member 204.

[0432] Figure 48(c) shows the drive transmission unit 203 having moved further in the direction of arrow M1B. The helical inclined surface 143d is holding back the approaching second brake engaging member 208. This suppresses the movement of the second brake engaging member 208 in the direction of M1B. On the other hand, the parts excluding the second brake engaging member 208 (i.e., the drum drive coupling 180 of the drive transmission unit 203, etc.) are moving in the direction of arrow M1B. Within the drive transmission unit 203, the second brake engaging member 208 is pushed in relative to the direction of arrow M1A.

[0433] In this state, as explained in Figure 44, the second brake engaging member 208 is disconnected from the brake member 206 and can rotate without receiving a rotational load. At this time, the brake member 206 is subjected to an elastic force F1 in the direction of the rotation axis M1 by the drum drive coupling spring 210 and the brake engaging spring 211 located inside the drive transmission unit 203. The helical inclined surface 143d moves the second brake engaging member 208, which is no longer subjected to a rotational load, in the direction of arrow C by the component force of the elastic force F1. In other words, the second brake engaging member 208 moves downstream in the rotation direction A along the helical inclined surface 143d.

[0434] Figure 48(d) shows the state immediately after the second brake engaging member 208 has moved downstream in the rotational direction (direction of arrow A). The second brake engaging member 208 moves along the helical inclined surface 143d of the drum coupling 143, and also moves in the M1B direction by the same amount as the entire drive transmission unit 203 has moved in the axial direction M1B, so it moves along the trajectory of arrow D. As a result, the second brake engaging member 208 moves away from the drive coupling 180 downstream in the rotational direction A, to a position where it can engage with the brake force receiving portion 143c (second side surface, second side portion) of the drum coupling 143. In other words, the helical inclined surface 143d is a guide for guiding the brake engaging member toward the brake force receiving portion 143c. In this embodiment, the helical inclined surface (top surface) 143d, which is the guide, has a downstream portion 143d1 and an upstream portion 143d2. The downstream portion (downstream slope, downstream top surface, downstream inclined portion) 143d1 is positioned between the brake force receiving portion 143c and the drive force receiving portion 143b. The upstream portion (upstream slope, upstream top surface, upstream inclined portion) 143d2 is located upstream of the drive force receiving portion 143b in the rotational direction (direction A). Therefore, the second brake engaging member 208 can be smoothly guided from the upstream portion 143d2 of the slope 143d through the downstream portion 143d1 to the brake force receiving portion 143c.

[0435] Figure 48(e) shows the drum coupling 143 moving (rotating) in the direction of arrow A due to the rotating drive transmission surface 180d, and as a result, the brake force receiving portion 143c is in contact with the second brake engagement member 208.

[0436] When the drive transmission unit 203 rotates in the direction of arrow A, the drive transmission surface 180d comes into contact with the drive force receiving portion 143b and transmits the drive force. The drive transmission surface 180d is a drive force applying portion that provides drive force to the drum coupling 143.

[0437] The drum coupling 143, which rotates by receiving driving force from the drive transmission surface 180d, also receives braking force when the brake force receiving portion 143c comes into contact with (engages with) the second brake engaging member 208.

[0438] In Figures 48(a) to (e), only the second brake engaging member 208 is shown among the first and second brake engaging members 204 and 208, which are brake engaging members. However, the first brake engaging member 204 (see Figure 43) is connected to the second brake member 208 so as to move integrally with the second brake member 208. Therefore, in the process shown in Figures 48(a) to (e), the first brake engaging member 204 also moves along the same trajectory as the second brake member 208. In the state shown in Figure 48(e), the first brake engaging member 204 engages with the brake force receiving portion 143c together with the second brake engaging member 208.

[0439] Figures 48(a) to 48(e) illustrate only the engagement process between the brake engagement members (204, 208) and the drum drive coupling 180 with respect to the coupling portion 143s, for the sake of simplicity in explanation. Similar to the coupling portion 143s, the coupling 143r also engages with the brake engagement members (204, 208) and the drum drive coupling 180. The engagement state of the brake engagement members (204, 208) and the drum drive coupling 180 with respect to the coupling 143r is shown in Figure 76(a).

[0440] To aid understanding of the process described so far, we will now provide further explanation using the perspective views in Figures 60 to 64. In Figures 60 to 64, a portion of the drum drive coupling 180 is omitted for illustrative purposes, revealing its internal shape.

[0441] Figure 60 is a perspective view showing the same state as Figure 48(a) described earlier. That is, the inclination start portion 143f of the drum coupling 143 is upstream of the projection 208e in the rotational direction (arrow A), and the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are in close proximity. Figure 61 shows the state after the drive transmission unit 203 has moved in the direction of arrow M1B from this state.

[0442] Figure 61 shows the state corresponding to Figure 48(b), where the helical inclined surface 143d is in contact with the inward projection 208e of the approaching second brake engaging member 208. The drive transmission unit 203 and the drum coupling 143 are relatively close to each other until they make contact, but the internal state of the drive transmission unit 203 remains unchanged. Figure 62 shows the state after the drive transmission unit 203 has moved further in the direction of arrow M1B.

[0443] Figure 62 shows the state corresponding to Figure 48(c), where the helical inclined surface 143d is holding back the approaching second brake engaging member 208. As a result, within the drive transmission unit 203, the second brake engaging member 208 is pushed relative to the drum drive coupling 180 in the direction of arrow M1A.

[0444] In this state, as explained in Figure 44, the second brake engaging member 208 is disconnected from the brake member 206 and can rotate without rotational load. At this time, the brake member 206 is subjected to an elastic force F1 in the direction of the rotation axis M1 by the drum drive coupling spring 210 and the brake engaging spring 211 located inside the drive transmission unit 203. The helical inclined surface 143d moves the second brake engaging member 208, which is no longer subjected to rotational load, in the direction of arrow C by the component force of the elastic force F1. In other words, the second brake engaging member 208 rotates downstream in the rotation direction A along the helical inclined surface 143d.

[0445] Figure 63 shows the state immediately after the second brake engaging member 208 has moved downstream in the rotational direction (direction of arrow A), and corresponds to Figure 48(c). The second brake engaging member 208 moves along the helical inclined surface 143d of the drum coupling 143, and also moves in the M1B direction by the same amount as the entire drive transmission unit 203 has moved in the axial direction M1B, so it moves along the trajectory of arrow D. As a result, the brake engaging members (204, 208) move away from the drive coupling 180 toward the downstream side in the rotational direction A, and move to a position where they can engage with the second side surface (brake force receiving portion 143c) of the drum coupling 143. When they reach this position, the brake engaging members (204, 208) return to a state where they can generate braking force.

[0446] Figure 64 shows a state where the drum coupling 143 is moved (rotated) in the direction of arrow A by the rotating drive transmission surface 180d, and as a result, the brake force receiving portion 143c is in contact with the second brake engaging member 208. Figure 64 corresponds to Figure 48(d).

[0447] When the drum drive coupling 180 of the drive transmission unit 203 rotates in the direction of arrow A from the state of Figure 64, the drive transmission surface 180d comes into contact with the driving force receiving portion 143b and transmits the driving force. The drum coupling 143 that is rotating by receiving the driving force from the drive transmission surface 180d also receives a brake force when the brake force receiving portion 143c comes into contact (engages) with the second brake engaging member 208 (see Figure 48(e)).

[0448] In summary, by going through the processes shown in Figures 48(a) to (e) and Figures 60 to 64, the brake engaging members (204, 208) move with respect to the drum drive coupling 180 and the drum coupling 143 as follows.

[0449] The brake engaging members (204, 208) move from a position close to the drive transmission surface 180d (Figures 48(a), Figure 60) to a position where the drum coupling 143 is sandwiched between the drive transmission surface 180d and the brake engaging members (204, 208) (Figures 48(d), Figure 64).

[0450] When the drive transmission surface 180d rotates from the state shown in Figures 48(d) and Figure 64, the drum coupling 143 rotates together with the drive transmission surface 180d and reaches the state shown in Figure 48(e). Then, the drum coupling 143 rotates in the direction of arrow A by the driving force received from the drum drive side coupling 180 while receiving an appropriate load (brake force) from the brake engaging members (204, 208). As a result, the torque required for the drum drive coupling 180 to rotate the drum unit does not become too light and becomes an appropriate magnitude, so the rotational drive of the drum unit becomes stable.

[0451] Next, with reference to FIGS. 49(a) to (e), another pattern of the engagement process of the drum drive coupling 180 and the brake engagement members (204, 208) with respect to the drum coupling 143 will be described. The drum coupling 143 has two coupling parts 143s and 143r. For simplicity, only the coupling part 143s will be described.

[0452] As shown in FIG. 49(a), a case where the phases of the inclined start portion 143f of the drum coupling 143 and the inward projection 208e of the second brake engagement member 208 satisfy the following relationship will be described. That is, the inclined start portion 143f of the drum coupling 143 is downstream in the rotational direction (arrow A) from the inward projection 208e.

[0453] FIG. 49(a) shows a state where the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are approaching each other.

[0454] The eaves 143g of the drum coupling 143 is in contact with the inward projection 208e of the second brake engagement member 208 that has approached in the M1B direction.

[0455] Next, FIG. 49(b) shows a state where the eaves 143g stops (blocks) the advancement of the second brake engagement member 208 that has approached. Here, the drum drive coupling 180, which is a component of the drive transmission unit 203, cannot be stopped from advancing in the M1B direction because it does not contact the eaves 143g. That is, the eaves 143g does not interfere because it is different in position from the shape of the drum drive coupling 180 in the radial direction. On the other hand, the second brake engagement member 208 has an inward projection 208e at the tip in the M1B direction. Since the inward projection 208e protrudes inward in the radial direction, it is in contact with the eaves 143g of the drum coupling 143.

[0456] Only the drum drive coupling 180 moves in the M1B direction, causing the second brake engagement member 208 to relatively move in the M1A direction with respect to the drum drive coupling 180. As described above, due to this relative movement, the second brake engagement member 208 can rotate without receiving a rotational load.

[0457] Next, Figure 49(c) shows the state in which the drive transmission unit 203 has started to rotate in the rotation direction A. First, when the drum drive coupling 180 starts to rotate in direction A, the second brake engaging member 208 also starts to rotate in direction A, pushed by the drum drive coupling 180.

[0458] The helical inclined surface 143d of the drum coupling 143 moves the second brake engaging member 208 in the direction of arrow C from the point where the inward projection 208e of the second brake engaging member 208 passes the inclination start portion 143f. In other words, the second brake engaging member 208 moves downstream in the rotation direction A and in the direction M1B.

[0459] Figure 49(d) shows the state after the second brake engaging member 208 has moved along the helical inclined surface 143d of the drum coupling 143, similar to Figure 48(d), and has passed the inclined surface 143d. At this time, the entire drive transmission unit 203 moves further in the axial direction M1B. As a result, the second brake engaging member 208 also moves in the M1B direction. The first brake engaging member 204 moves along the trajectory of arrow D.

[0460] The subsequent engagement is the same as described in Figure 48(d), and the completed engagement state is as shown in Figure 48(e). In this embodiment, the awning 143g is connected to the upstream portion (upstream slope, upstream top surface) 143d2 of the helical slope 143d. The inclination start portion 143f is the boundary between the awning 143g and the helical slope 143d. Therefore, the second brake engagement member 208, whose movement was blocked by the awning 143g, can smoothly transition to a state of contact with the helical slope 143d as the drive transmission unit 203 rotates. However, the configuration is not necessarily limited to this, and there may be a gap between the awning 143g and the slope 143d.

[0461] In Figures 49(a) to (d), only the second brake engaging member 208 is shown among the brake engaging members (204, 208). However, as mentioned above, even in the process shown in Figures 49(a) to (d), the first brake engaging member 204 (see Figure 43) moves integrally with the second brake engaging member 208.

[0462] Here, to aid understanding of the process explained using Figures 49(a) to (d), we will provide further explanation using the perspective views in Figures 65 to 68. In Figures 65 to 68, a portion of the drum drive coupling 180 is omitted for illustrative purposes, revealing its internal shape.

[0463] Figure 65 shows the state in which the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are approaching each other. At this time, the visor 143g of the drum coupling 143 is in contact with the second brake engagement member 208 which is approaching in the M1B direction. Figure 65 corresponds to Figure 49(a).

[0464] Next, Figure 66 shows the state in which the drum drive coupling 180 has moved to the right (M1B direction) along the axial direction relative to the second brake engagement member 208. In Figure 66, the visor 143g is stopping (blocking) the progress of the approaching second brake engagement member 208.

[0465] Figure 66 corresponds to Figure 49(b). The second brake engaging member 208 moves relative to the drum drive coupling 180 to the left in the axial direction (M1A direction). As described above, this relative movement allows the second brake engaging member 208 to rotate without being subjected to rotational load.

[0466] Next, Figure 67 shows the state in which the drive transmission unit 203 has started to rotate in the rotation direction A. Figure 67 corresponds to Figure 49(c). The helical inclined surface 143d of the drum coupling 143 moves the second brake engaging member 208 in the direction of arrow C from the point where the second brake engaging member 208 has passed the inclination start portion 143f. Figure 68 corresponds to Figure 49(d). In the state shown in Figure 68, the first brake engaging member 204 moves along the helical inclined surface 143d of the drum coupling 143, similar to the states shown in Figure 48(d) and Figure 63. Furthermore, as the entire drive transmission unit 203 moves in the axial direction M1B, the first brake engaging member 204 also moves in the M1B direction. As a result, the first brake engaging member 204 moves along the trajectory of arrow D.

[0467] Then, as described above, the entire drive transmission unit 203 continues to rotate, completing the connection and resulting in a state similar to that shown in Figure 48(e).

[0468] Next, another pattern of the engagement process of the drum drive coupling 180 and brake engagement members (204, 208) with respect to the drum coupling 143 will be described using Figures 50(a) to (d). Note that the drum coupling 143 has two coupling portions 143s and 143r, but for simplicity, only coupling portion 143s will be described.

[0469] As shown in Figure 50(a), the following case will be described where the relative phases of the inclined starting portion 143f of the drum coupling 143 and the inward projection 208e of the second brake engaging member 208 satisfy the following relationship. In other words, the case where the inclined starting portion 143f of the drum coupling 143 is on the downstream side in the rotational direction (arrow A) will be described.

[0470] Figure 50(a) shows the state in which the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are separated.

[0471] Next, Figure 50(b) shows the state in which the visor 143g is stopping the movement of the approaching second brake engaging member 208. Here, the drum drive coupling 180, which is a component of the drive transmission unit 203, does not come into contact with the visor 143g and therefore cannot stop its movement. As a result, the second brake engaging member 208 moves relative to the drum drive coupling 180 in the M1A direction. As mentioned above, this relative movement allows the second brake engaging member 208 to rotate without being subjected to rotational load. Here, the visor 143g does not interfere with the drum drive coupling 180 because its shape and radial position are different.

[0472] Next, Figure 50(c) shows the state in which the drive transmission unit 203 has rotated in rotational direction A and is in contact with the second brake engagement member. The second brake engagement member 208 does not start rotating on its own and remains in that position, while the drum drive coupling 180 rotates and comes into contact with the second brake engagement member 208. After this, if it rotates further, the second brake engagement member 208 and the drum drive coupling 180 will rotate together as a single unit.

[0473] Figure 50(d) shows the second brake engaging member 208 after further rotation, having passed the inclination start portion 143f of the drum coupling 143. In this state, as explained in Figure 48(c), the second brake engaging member 208 moves in the direction of arrow C. The subsequent operation is the same as described above and will be omitted here.

[0474] In Figures 50(a) to (d), only the second brake engaging member 208 is shown among the brake engaging members (204, 208). However, as mentioned above, even in the process shown in Figures 50(a) to (d), the first brake engaging member 204 (see Figure 43) moves integrally with the second brake engaging member 208.

[0475] Here, to aid understanding of the process explained using Figures 50(a) to (d), we will provide further explanation using the perspective views in Figures 69 to 72. In Figures 69 to 72, a portion of the drum drive coupling 180 is omitted for illustrative purposes, revealing its internal shape.

[0476] Figure 69 corresponds to Figure 50(a), and shows a state in which the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are separated by the amount of the gap G1.

[0477] Next, Figure 70 corresponds to Figure 50(b) and shows the state in which the entire drive transmission unit 203 has moved in the M1B direction. It shows the state in which the drum drive coupling 180 has moved to the right in the axial direction (M1B direction) relative to the second brake engaging member 208, with the visor 143g stopping the movement of the approaching second brake engaging member 208. At this time, the second brake engaging member 208 moves relative to the drum drive coupling 180 to the left (M1A direction). As mentioned above, this relative movement allows the second brake engaging member 208 to rotate without being subjected to rotational load.

[0478] Next, Figure 71 corresponds to Figure 50(c), and shows the state in which the drum drive coupling 180 of the drive transmission unit 203 is in contact with the second brake engagement member 208 as it rotates in rotational direction A.

[0479] The second brake engagement member 208 cannot rotate when it is not receiving rotational force from the drum drive coupling 180, and therefore remains stationary in its initial position without rotating immediately after the drive transmission unit 203 starts operating. In other words, only the drum drive coupling 180 starts rotating in direction A first. As a result, Figure 71 shows the state in which the drum drive coupling 180 is in contact with the second brake engagement member 208.

[0480] Figure 72 corresponds to Figure 50(d), and shows the state in which the drum drive coupling 180 and the second brake engaging member 208 come into contact, causing both the drum drive coupling 180 and the second brake engaging member 208 to begin rotating in direction A. More specifically, the second brake engaging member 208 is pushed by the drum drive coupling 180 and rotates in direction A, causing the second brake engaging member 208 to pass the inclination start portion 143f of the drum coupling 143. In this state, as explained in Figure 48(c) and Figure 62, the second brake engaging member 208 is guided by the inclined surface 143d and moves in the direction along the inclination of the inclined surface 143d (direction of arrow C).

[0481] The subsequent steps are the same as those described above using Figures 48(c) to 48(e) and Figures 62 to 64, so they will be omitted here.

[0482] As described above, when the cartridge 100 is attached to the main body of the image forming apparatus, the phase (arrangement) of the drive transmission unit 203 with respect to the drum coupling 143 is not determined (see FIGS. 48(a), 49(a), 50(a), 60, 65, 69). However, in any case, the drum coupling 143 can be connected to the drive transmission unit 203. The drive transmission unit 203 has not only the drum drive coupling 180 but also brake engaging members (204, 208), and both of them can engage with the drum coupling 143.

[0483] Next, the mutual configurations (mutual shapes) for aligning (squaring) their respective axes in the process until the drive transmission unit 203 and the drum coupling 143 are connected will be described using FIG. 51. FIG. 51 shows a cross-sectional view of the drive transmission unit 203 and the drum coupling 143, and FIG. 51(a) shows the shape of the connected state of this embodiment. The circular hole portion 143a of the drum coupling 143 engages with the positioning boss 180i of the drum drive coupling 180 to align the positions of their respective axes. Also, a conical guide surface 143h is provided at one end of the circular hole portion 143a. That is, the guide surface 143h is a part of the inner surface of the coupling 143 that has a conical shape. This guide surface 143h is provided to guide the misalignment between them when the drive transmission unit 203 is still separated in the axial direction M1B and starts to engage, so as to align their respective axes.

[0484] In addition to this embodiment, as shown in FIG. 51(b), it is also possible to engage with the positioning boss 180i without providing a guide surface in the circular hole portion 143a of the drum coupling 143. Also, as shown in FIG. 06(c), the guide surface 143h can be enlarged to reduce the fitting between the circular hole portion 143a and the positioning boss 180i. Also, as shown in FIG. 51(d), the diameter of the circular hole portion 143a can be enlarged. These can be selected according to the method of determining the relative position and the accuracy between the drive transmission unit 203 and the process cartridge 100.

[0485] The circular hole 143a is preferably long enough to accommodate the positioning boss 180i. That is, as shown in Figure 95, the positioning boss 180i enters at least the area Pb on the axis L of the drum unit. The circular hole 143a is formed so as to include the entirety of this area Pb. In other words, the area Pb is open around the axis L.

[0486] In Figure 95, the area occupied by the brake force receiving portion 143c, the helical slope (top surface) 143d, the awning 143g, and the driving force receiving portion 143b (not shown) on the axis L is Pa, and in this embodiment, region Pa is contained within region Pb.

[0487] The projection area Pa of the brake force receiving portion 143c, the slope 143d, the awning 143g, and the driving force receiving portion 143b, when projected onto the axis L, is formed to at least partially overlap with the projection area Pb of the circular hole portion 143a.

[0488] As described above, in this embodiment, the coupling 143 of the cartridge 100 receives driving force from the drive transmission unit 203 of the image forming apparatus body. In addition, the coupling 143 activates the brake mechanism (brake member 206) inside the drive transmission unit 203 in conjunction with receiving driving force from the drive transmission unit 203. The drum coupling 143 can receive braking force via the brake engagement members (204, 208).

[0489] This braking mechanism allows the load required to drive the cartridge to be set within an appropriate range. As a result, the cartridge 100 can be driven stably.

[0490] It is also possible to rotate components other than the photoreceptor drum 104, such as the developing roller or toner transport roller, using the drum coupling 104 and drive transmission unit 203 of this embodiment. However, for the following reasons, the drum coupling 104 and drive transmission unit 203 of this embodiment are particularly suitable for rotating the photoreceptor drum 104.

[0491] The cartridge 100 in this embodiment has a photoreceptor drum 104 but does not have a cleaning means that contacts the photoreceptor drum 104. Therefore, the torque of the photoreceptor drum 104 is relatively small, and the photoreceptor drum 104 is prone to speed fluctuations when affected by the surroundings during rotational drive. To address this, the drive transmission unit 203 rotates the photoreceptor drum 104 while applying a constant load to it. In other words, the coupling 143 not only receives the driving force from the drive transmission unit 203 to rotate the photoreceptor drum, but also receives a braking force that suppresses the rotation of the photoreceptor drum. By receiving two forces acting in different rotational directions simultaneously, the coupling 143 suppresses speed fluctuations of the photoreceptor drum 104 (drum unit 103) and stabilizes its rotation.

[0492] Furthermore, even for cartridges that have a cleaning means, driving force can be input from the drive transmission unit 203 of this embodiment via the coupling 143. When the cartridge 100 has a cleaning means (for example, a cleaning blade) that contacts the surface of the photoreceptor drum to remove toner from the photoreceptor drum, a frictional force is generated between the photoreceptor drum and the cleaning means. This frictional force increases the torque of the photoreceptor drum 104. However, even in this case, the torque of the photoreceptor drum 104 may not be large enough. In this case, as in this embodiment, if the coupling 143 is made capable of receiving both driving force and braking force from the drive transmission unit 203 simultaneously, the torque required to rotate the photoreceptor drum 104 will increase, and the rotation of the photoreceptor drum will become stable. A cartridge with a cleaning means will be described in Embodiment 2 below.

[0493] In this embodiment, the brake mechanism for applying an appropriate rotational load to the photoreceptor drum is located on the main body of the image forming apparatus, i.e., the drive transmission unit 203, rather than on the cartridge. Therefore, there is no need to place a brake mechanism on the process cartridge, which is a removable unit that is replaced after use. This contributes to miniaturization and cost reduction of the process cartridge.

[0494] Furthermore, the coupling 143 has a shape that allows it to smoothly engage with both the driving force applying member (drum drive coupling 180) and the braking force applying member (brake engaging members (204, 208)) provided on the drive transmission unit 203. For example, the coupling 143 is made easier to smoothly connect with the drive transmission unit 203 by having a helical inclined surface 143d (inclined part, guide, top surface, upper side part) and an overhang 143f.

[0495] The shape of the coupling 143 in this embodiment will be described in more detail below with reference to Figure 79.

[0496] The coupling 143 has two coupling portions 143s and 143r, each coupling portion having an engaging portion 143i and a guide forming portion 143j. The engaging portion 143i is a shaped portion for engaging with a driving force applying member (drum drive coupling 180) or a braking force applying member (brake engaging members (204, 208)). The engaging portion 143i forms a driving force receiving portion 143b, a braking force receiving portion 143c, and a downstream slope 143d1.

[0497] The driving force receiving portion 143b and the braking force receiving portion 143c engage with the drum drive coupling 180 and the brake members (204, 208), respectively. Although the driving force receiving portion (first side surface, first side portion) 143b and the braking force receiving portion (second side surface, second side portion) 143c are formed in a planar shape, the configuration is not limited to this. They only need to be configured to receive driving force and braking force, respectively, and may be curved or have a minute surface area. For example, the edge (ridge) formed by the engaging portion 143i may form the driving force receiving portion (first side surface, first side portion) 143b or the braking force receiving portion (second side surface, second side portion) 143c.

[0498] Alternatively, the driving force receiving portion 143b or the braking force receiving portion 143c may be a part formed by multiple separated regions. In other words, the engaging portion 143i may be a collection of multiple shaped parts.

[0499] The driving force receiving portion 143b and the braking force receiving portion 143c are the upstream and downstream sides of the engaging portion 143i, respectively. In other words, the driving force receiving portion 143b is the side facing upstream in the direction of rotation, and the braking force receiving portion 143c is the side facing downstream in the direction of rotation.

[0500] Furthermore, the guide forming portion 143n is a projection (extended portion) that extends in the rotational direction toward the engagement portion 143i. The top surface (upper part) of the guide forming portion 143n is the upstream slope (upstream top surface, upstream inclined portion) 143d2. The upstream slope 143d2 is a guide (upstream guide, upstream guide) and inclined portion for guiding the braking force applying member (brake engagement member (204, 208)) toward the engagement portion 143i.

[0501] In other words, the guide-forming portion 143n is a projection for forming the upstream slope 143d2, which is a guide (upstream guide).

[0502] The guide forming portion 143n is adjacent to the engaging portion 143i and extends from upstream to downstream in the rotational direction toward the engaging portion 143i. Furthermore, the upstream slope 143d2 of the guide forming portion 143n is inclined to approach the non-driven end of the photoreceptor drum as it moves from upstream to downstream in the rotational direction (see Figure 80).

[0503] In Figure 80, the drum coupling 143 is positioned near the first end (drive-side end) 104a of the photoreceptor drum 104. In other words, the first end 104a of the photoreceptor drum 104 is the end that receives the driving force from the drum coupling 143.

[0504] The end of the photoreceptor drum 104 opposite to the first end 104a is the non-driven end (second end) 104b. The distances from this non-driven end 104b to the upstream slope 143d2 are indicated by D1 and D2. Distance D1 is the distance measured along the axial direction parallel to axis L from the non-driven end 104b of the photoreceptor drum to the downstream end of the slope 143d2. D2 is the distance measured along the axial direction from the non-driven end 104b of the photoreceptor drum to the upstream end of the upstream slope 143d2.

[0505] At this point, distance D1 is shorter than distance D2. In other words, when measuring along the axial direction from the non-driven end 104b of the photoreceptor drum to the upstream slope 143d2, the distance decreases as you move downstream in the rotational direction.

[0506] In other words, the upstream slope 143d2 is inclined to approach the non-driven end 104b of the photoreceptor drum as it moves downstream in the rotation direction A. Not only the upstream slope 143d2, but also the downstream slope 143d1 is inclined in the same direction.

[0507] Distances D1 and D2 can also be considered as the distance measured along the axial direction from the non-driven end of the cartridge casing (i.e., the non-driven cartridge cover 117: see Figure 14) to the upstream slope 143d2.

[0508] In addition, one of the guide forming portion 143n and the engaging portion 143i may be referred to as the first shaped portion, and the other as the second shaped portion, and so on.

[0509] In this embodiment, the first shaped portion and the second shaped portion (i.e., the guide forming portion 143n and the engaging portion 143i) are adjacent and connected to each other. More specifically, the downstream side of the guide forming portion 143n in the rotational direction is connected to the engaging portion 143i. However, although the engaging portion 143i and the guide forming portion 143n are adjacent, they may not be connected and a gap may be formed between them.

[0510] In this embodiment, the top surface (downstream slope) 143d1 of the engaging portion 143i is smoothly connected to the top surface (upstream slope) 143d2 of the guide forming portion 143n, and together they form a single slope (top surface) 143d.

[0511] In other words, the top surface (downstream slope) 143d2 of the engaging portion 143i, like the upstream slope 143d1, is part of a guide that guides the brake engaging members (204, 208) to a position where they can engage with the brake force receiving portion 143c.

[0512] Furthermore, the downstream slope (downstream top surface) 143d2 does not necessarily have to be continuous with the upstream slope (upstream top surface) 143d1. Examples of discontinuous configurations between the upstream slope 143d2 and the downstream slope 143d1 are shown in Figures 81(a) and (b). Figures 81(a) and (b) show modified examples in which a step is provided between the upstream slope 143d2 and the downstream slope 143d1 to separate them in the axial direction, and the downstream slope 143d1 is changed to a flat surface. In this way, a part of the spiral slope 143d, which serves as a guide, may be flat or have a step.

[0513] As shown in Figures 48(c), 49(c), 50(d), 62, 67, and 72, the brake engaging members (204, 208) are guided in the direction of arrow C along the inclination direction of the inclination surface 143 by contacting the inclined surface 143d. In other words, the brake engaging members (204, 208) move downstream in the rotational direction and toward the non-driven side of the photoreceptor drum (M1B direction).

[0514] After being guided by the inclined surface 143d, the brake engaging members (204, 208) further advance axially (in the M1B direction) toward the space located downstream of the brake force receiving portion (second side surface) 143c of the drum coupling 143 (see Figures 48(d), 49(d), 63, and 68). As a result, the brake engaging members (204, 208) become capable of engaging with the brake force receiving portion 143c.

[0515] Furthermore, as the brake engaging members (204, 208) are guided by the inclined surface 143d, they move downstream in the rotational direction A, away from the drum drive coupling 180. As a result, a gap is created between the drum drive coupling 180 and the brake engaging members (204, 208). The engaging portion 143i of the drum coupling 143 fits into this gap, and the driving force receiving portion (side surface) 143b becomes capable of engaging with the drum drive coupling 180 (see Figures 48(d), (e), 49(d), 63, 64, and 68).

[0516] The helical inclined surface 143d also has the function of moving the brake engagement members (204, 208) away from the drum drive coupling 180 so that the drum drive coupling 180 and the drive force receiving portion 143b can engage.

[0517] The spiral inclined surface (top surface) 143d has not only a portion (downstream guide, downstream guide, downstream top surface, downstream inclined portion) 143d1 located between the brake force receiving portion 143c and the drive force receiving portion 143b, but also a portion (upstream guide, upstream top surface, upstream inclined portion) 143d2 located upstream of the drive force receiving portion 143b (see Figures 48(a), 47, 56, etc.). By increasing the area where the inclined surface 143d is located, the top surface 143d can reliably guide the brake engagement members (204, 208).

[0518] In other words, even when the brake engaging members (204, 208) are located upstream of the driving force receiving portion 143b (see Figure 49(a)), they can be moved through the upstream slope 143d2 to the space downstream of the brake force receiving portion 143c (see Figures 49(c), (d)).

[0519] In this embodiment, the entire slope 143d was an inclined section. Both the downstream top surface 143d1 and the upstream top surface 143d2 were slopes that descended downwards in the direction of rotation.

[0520] However, it is also possible to tilt only a portion of the top surface, the inclined surface 143d. For example, as mentioned above, the upstream side of the top surface may be inclined as the upstream inclined surface 143d2, while the downstream side of the top surface (downstream top surface 143d2) may not be inclined and may be a flat plane perpendicular to the axis of the drum unit (see Figures 81(a) and (b)). In the modified drum coupling shown in Figures 81(a) and (b), the brake engaging members (204, 208) can be moved vigorously by the inclination of the upstream inclined surface (upstream top surface) 143d2, and their inertia (momentum) can be used to pass over the flat downstream top surface 143d1.

[0521] Furthermore, a configuration is conceivable in which only the upstream top surface (upstream slope 143d2) is used as a guide for the brake engagement members (204, 208), and the downstream top surface (downstream slope 143d1) is not used. In other words, a configuration is conceivable in which the portion corresponding to the downstream top surface is almost nonexistent, or is very short compared to the upstream top surface. Such a configuration will be described later using Figure 74.

[0522] Furthermore, it is conceivable that a partially uphill section exists within the downhill spiral inclination 143d. Even in such a case, if the inclination 143d can sufficiently guide the brake engagement members (204, 208) toward the downstream direction of rotation, the inclination 143d can be considered as a downhill slope. In other words, even if there is a partially uphill section, the spiral inclination 143d can be considered as a downhill slope overall. To put it another way, the distance from the non-driven end of the cartridge to the spiral inclination 143d can be considered to decrease as the spiral inclination 143d moves toward the downstream direction of rotation.

[0523] In such a configuration, it is conceivable that the uphill sections partially located within the spiral slope 143d are sufficiently short compared to the other downhill sections, or that the slope of the uphill sections is gentle, so that the influence of the uphill sections on the downhill sections is small.

[0524] Furthermore, the helical slope 143d may be curved in shape or divided into multiple regions. Also, at least a portion of the slope 143d may be very short, and the helical slope 143d may be considered an edge rather than a surface. In addition, the helical slope 143d was fan-shaped (helical) when the drum coupling 143 was viewed from the front. However, the shape of the guide (top surface, inclined part) to be provided on the drum coupling 143 is not limited to this. For example, instead of using a fan-shaped (helical) slope 143d, a linearly extending rectangular slope may be used. In other words, it is possible to use an inclined part (guide, top surface) equivalent to the helical slope 143d with modified shape, size, and direction of extension. Some examples of this will be described later using Figure 54, etc.

[0525] Furthermore, the upstream slope (upstream top surface) 143d2 is configured to have a region that is narrower than the downstream slope (downstream top surface) 143d1 (see Figures 47 and 56). Conversely, the downstream slope 143d1 has a region that is wider than the upstream slope 143d2.

[0526] Here, the width of each slope is the length measured along the radial direction. Also, as shown in Figure 79, at least a portion of the engaging portion 143i is located further away from the axis L of the drum unit in the radial direction than the guide forming portion 143n. In other words, at least a portion of the engaging portion 143i is located radially outward from the guide forming portion 143n.

[0527] This dimensional and arrangement relationship is due to the fact that the driving force receiving portion 143b of the engaging portion 143i is positioned near the boundary between the guide forming portion 143n and the engaging portion 143i. In other words, a part of the engaging portion 143i protrudes radially outward from the guide forming portion 143n in order to form the driving force receiving portion 143b. As a result, the downstream portion 143d1 of the inclined surface (top surface) 143d is wider than the upstream portion 143d2.

[0528] The driving force receiving portion 143b has a region located radially outward (farther from the axis L) than the upstream slope 143d2. Also, in the axial direction of the drum unit, the driving force receiving portion 143b is located closer to the non-driven end of the photoreceptor drum than the upstream slope 143d2. Figure 80 shows a state in which the distance D3 measured along the axial direction from the non-driven end 104b of the photoreceptor drum to the driving force receiving portion 143b is shorter than the distance D1 from the non-driven end 104b of the photoreceptor drum to the upstream top surface 143d2.

[0529] Conversely, at least a portion of the upstream slope 143d2 is located further away from the non-driven end 104b of the photoreceptor drum than the driving force receiving portion 143b in the axial direction. The upstream slope 143d2 is a tip portion located closer to the tip of the drum coupling 143 than the driving force receiving portion 143b.

[0530] Distances D1 and D3 can also be considered as the distances measured along the axial direction, starting from the non-driven end of the cartridge (i.e., the non-driven cartridge cover 117: see Figure 14) to the upstream slope 143d2 and the driving force receiving portion 143b, respectively.

[0531] The visor 143d is a blocking part (stopper) that suppresses (blocks) the axial movement of the brake engagement members (204, 208). In other words, the visor 143d blocks the brake engagement members (204, 208) from approaching the drum coupling 143 and entering an area where they cannot engage with the brake force receiving part 143c. Figures 66 and 49(b), and 69 and 50(a) show this blocking state.

[0532] In this embodiment, the awning (block portion) 143d is located further upstream in the rotational direction than the upstream slope 143d2, and the awning 143d is continuous with the top surface of the guide forming portion 143n (upstream slope 143d2) (see Figure 56(d)).

[0533] If the brake engagement members (204, 208) enter the space upstream of the drive force receiving portion 143b or the space downstream of the brake force receiving portion 143c together with the drum drive coupling 180, the brake engagement members (204, 208) will be unable to engage with the brake force receiving portion 143c. The visor 143g blocks the movement of the brake engagement members (204, 208) to prevent such a situation from occurring.

[0534] In this embodiment, when the drum unit is viewed from the drive side along the axial direction (see Figure 47(a)), the visor 143g of the first coupling portion 143s is positioned to cover the space upstream of the drive force receiving portion 143b. Furthermore, the visor 143g is positioned to cover the space downstream of the brake force receiving portion 143c.

[0535] Furthermore, the awning 143d has a width sufficient to cover at least a portion of the downstream portion (downstream slope 143d1) of the helical slope (top surface) 143d. This prevents the brake engagement members (204, 208) from unintentionally entering the space upstream of the drive force receiving portion 143b or the space downstream of the brake force receiving portion 143c together with the drum drive coupling 180.

[0536] On the other hand, the visor 143g is positioned to allow the brake engagement members (204, 208) to enter the space downstream of the brake force receiving portion independently of the drum drive coupling 180 (see Figures 50(d), 49(c), and 48(c)).

[0537] In other words, after passing the awning 143g, the brake engaging members (204, 208) come into contact with the upstream slope 143d2 and are guided along the slope 143d toward the space downstream of the brake force receiving portion 143c (see Figures 49(c) and 50(d)).

[0538] In other words, the awning 143g releases the blocking state of the brake engaging members (204, 208) when the brake engaging members (204, 208) are in a state where they can come into contact with the upstream portion (upstream top surface) 143d2 of the slope (top surface) 143d.

[0539] The awning 143g is adjacent to the upstream slope 143d2 and is located upstream of the upstream slope 143d2. In this embodiment, the top surface of the awning 143g and the upstream slope 143d2 were connected, but there may also be cases where the awning 143g and the upstream slope 143d2 are adjacent to each other, but a gap is formed between them.

[0540] Furthermore, the top surface of the awning 143g was a plane perpendicular to the axis L of the drum unit, but it is not limited to this shape. For example, the top surface of the awning 143g could be inclined in the same direction as the upstream slope 143d2. In this case, the awning 143g can be considered to form a part of the upstream slope 143d2. Alternatively, a part of the guide forming portion 143n could be considered to form the awning 143g.

[0541] In this embodiment, the coupling 143 had two helical inclined surfaces 143d, two awnings 143g, two driving force receiving portions 143b, and two brake force receiving portions 143c. In other words, the coupling 143 had a shape symmetrical with respect to its axis and had two coupling portions 143s and 143r (see Figure 58). The coupling portions 143s and 143r each had a helical inclined surface (inclined portion) 143d as a top surface. The brake engaging members (204, 208) and the drum driving member 180 engaged with the coupling portions 143s and 143r, respectively, as shown in Figure 76(a).

[0542] Examples of other shapes (modified versions) of the coupling 143 will be described later.

[0543] The drive transmission unit 203 includes a first brake engaging member 204 and a second brake engaging member 208 as brake force applying members (brake engaging members) that apply braking force to the coupling 143 to load the rotation of the photoreceptor drum. There is a gap between the first brake engaging member 204 and the second brake engaging member 208, and the second brake engaging member 208, which is positioned radially inward, can bend to move slightly radially outward to approach the first brake engaging member 204. When the coupling 143 and the drive transmission unit 203 are released, the second brake engaging member 208 bends, allowing it to smoothly disengage from the coupling 143. For example, the second brake engaging member 208 can bend over the overhang 143g and detach from the coupling 143. [Various modifications of the coupling and cartridge shown in Example 1]

[0544] Furthermore, a modified example (modified shape) of the drum coupling 143 of Example 1 described above will be explained. Even when the visor 143g described earlier is not placed on the drum coupling 143, it can still function under certain conditions.

[0545] Figure 52 shows a perspective view of the drum coupling 143 without the visor 143g, and Figure 53 shows an unfolded diagram illustrating the engagement process.

[0546] The shape will be explained using Figure 52. Figure 52 shows one end of the drum unit, illustrating that a coupling member (drum coupling) 143 is attached to the end of the photoreceptor drum 104. The drum coupling 143 has a helical inclined surface 143d as well as a push-back surface 143k, which will be described later, but it does not have an overhang shape.

[0547] Next, the process up to engagement with the drive transmission unit 203 will be explained using Figure 53.

[0548] The unfolded view in Figure 53 is represented in the same way as the unfolded view in Figure 48. The drum coupling 143 has two coupling parts 143s and 143r, but for the sake of simplicity, only coupling part 143s will be described. The description of coupling part 143s also applies to coupling part 143r.

[0549] The following describes the case where the relative phases of the inclined starting portion 143f of the drum coupling 143 and the inward projection 208e of the second brake engaging member 208, as shown in Figure 53(a), satisfy the following relationship. In other words, the case where the inclined starting portion 146f of the drum coupling 143 is on the downstream side in the rotational direction (arrow A) is described.

[0550] Figure 53(a) shows the state in which the drive transmission surface 180d of the drive transmission unit 203 and the second brake engagement member 208 are in close proximity.

[0551] Next, in Figure 53(b), since there is no overhang, the drum coupling 143 shows the drum drive coupling 180 and the second brake engagement member 208 moving into the space between the pushback surface 143k and the helical inclined surface 143d3.

[0552] Figure 53(c) shows the state in which the drive transmission unit 203 has begun to rotate in rotational direction A. When the drum drive coupling 180 and the second brake engaging member 208 rotate, the second brake engaging member 208 moves in the direction of arrow E along the slope due to the action of the inclination θ1 of the pushback surface 143k or the action of the inclination θ2 of the second brake engaging member 208. As explained in Figure 48, the second brake engaging member 208 can rotate without being subjected to rotational load.

[0553] As explained above, when the brake engagement members (204, 208) enter a region where they cannot engage with the brake force receiving portion, the pushback surface (pushback portion) 143k applies force to the second brake engagement member 208. This causes the pushback surface 143k to push the brake engagement members (204, 208) back toward the interior of the drive transmission unit 203, moving them in the direction of arrow E.

[0554] However, the second brake engaging member 208 is biased in the direction M1B in the figure by the spring 211 shown in Figure 43, and if the component force of the inclination θ2 of the second brake engaging member 208 is smaller than the spring force F1, the second brake engaging member 208 cannot be moved in the direction of arrow E. The component force changes depending on the load torque of the drum holding unit 108 and the angle of each inclined surface (θ1 or θ2). It is best to set the relative magnitudes of the forces within a range where the above effect holds, taking into account the component forces and frictional forces.

[0555] Figure 53(d) shows the movement of the second brake engaging member 208 after it is no longer subjected to rotational load. The drive transmission unit 203 has rotated further, and the second brake engaging member 208 has passed the inclination start portion 146f of the drum coupling 146. In this state, as explained in Figure 48(c), the second brake engaging member 208 moves in the direction of arrow C. The subsequent operation is the same as described above and will be omitted here.

[0556] Although not shown in Figures 50(a) to (d), the first brake engagement member 204 also moves together with the second brake engagement member 208 during these processes.

[0557] In Example 1 (see Figure 1(a)), the drum coupling 143 was blocked by the overhang 143g from entering a region where the brake engagement members (204, 208) could not engage with the brake force receiving portion. In contrast, in the drum coupling 143 of this modified example, when the brake engagement members (204, 208) enter a region where they cannot engage with the brake force receiving portion 143c together with the drum drive coupling 180, the push-back surface (push-back portion) 143k pushes back the brake engagement members (204, 208). The push-back surface 143k is an inclined portion that is inclined in a different direction from the helical inclined surface 143. In other words, the helical inclined surface 143 is the part that slopes toward the non-driven side of the drum unit as it moves downstream in the direction of rotation, whereas the pushback surface 143k is the part that slopes toward the outside of the drum unit, that is, away from the non-driven end 104b (see Figure 80) of the photoreceptor drum, as it moves downstream in the direction of rotation A. If the helical inclined surface 143 is considered a downhill slope, then the pushback surface 143k is an uphill slope. The pushback surface 143k is located upstream of the helical inclined surface 143d in the direction of rotation and is adjacent to the helical inclined surface 43k.

[0558] The pushback surface 143k also serves as a guide (second guide) for guiding the brake engagement members (204, 208) toward the helical inclined surface 143d. The pushback surface 134k is a helical inclined surface (second helical inclined surface, second inclined portion) whose inclination direction is opposite to that of the helical inclined surface 143d.

[0559] Furthermore, another variation of the drum coupling 143 will be described. The inclined portion and the top surface (helical inclined surface 143d) acting as a guide, as described in Example 1, are formed as smooth inclined surfaces, and the brake engagement members (204, 208) were guided along these surfaces (see Figure 56, etc.). However, the drum coupling 143 can also function even if the inclined portion has a different shape. One example of this is shown in a perspective view in Figure 54.

[0560] First, the shape shown in Figure 54(a) is a reproduction of the shape described in Example 1. A gently sloping helical surface 143d is formed from the inclination start portion 143f toward the brake force receiving portion 143c.

[0561] On the other hand, the shapes in Figures 54(b) and 73(a) show modified examples. The height between the inclination start portion 147f and the brake force receiving portion 147c changes in a step-like manner. In other words, the top surface (inclined portion) is a stepped portion 147d, and the inclination is formed by multiple steps. Thus, the inclined portion (top surface) may be a spiral step rather than a spiral slope, and may descend in the direction in which the second brake engaging member 208 advances, thus forming the inclination.

[0562] The stepped portion 147d has the same function as the helical inclined surface 143d in Figure 54(a) by moving the second brake engaging member 208 in the direction of arrow C in Figure 73(a). While the inclined surface 143d is an inclined portion consisting of continuously inclined surfaces, the stepped portion 147d can be considered an inclined portion that is inclined in stages by multiple planes.

[0563] If it is difficult to form a helical inclined surface 143d on the coupling 143 due to limitations in the configuration of the mold for manufacturing the coupling 143, a stepped portion 147d can be used instead of the inclined surface 143d.

[0564] In this case, it is preferable to configure the second brake engaging member 208 so that when it comes into contact with the stepped portion 147d, which is the top surface, the second brake engaging member 208 does not get caught on the stepped portion 147d and is smoothly guided. For example, the width of each plane of the stepped portion 147d can be made sufficiently narrow. Also, in Figure 73(a), the top surface (inclined portion, guide) was constructed in a stepped shape by combining multiple planes, but the same function can be achieved by constructing the top surface (inclined portion, guide) by combining multiple curved surfaces. The stepped portion 147d, like the inclined surface 143d, is a guide (inclined portion) for guiding the brake engaging members (204, 208) toward the brake force receiving portion by its own inclination.

[0565] Furthermore, as shown in Figures 54(c) and 73(b), the top surface may be divided into an inclined surface (upstream top surface, downstream top surface) 148d1 and an inclined surface (downstream top surface, downstream guide, downstream top surface) 148d2, with a space 148g between them. Even in this case, if the shape is such that no snagging occurs when the second brake engaging member 208 contacts the top surface (148d1, 148d2), the top surface (148d1, 148d2) can fulfill its function as a guide. Such a coupling can be used when there are limitations on the configuration of the mold for forming the coupling.

[0566] Furthermore, Figures 54(d) and 73(c) show modified examples in which the shape of each part of the coupling 143 is constructed using ribs. The top surface (inclined surface 149d) is composed of the surfaces of multiple ribs 149p, and the top surface can be divided into multiple parts, yet it can still function in the same way. In other words, as shown in Figure 73(c), the guide forming part 149n that forms the upstream top surface (upstream guide, upstream inclined part) 149d2 is a radially protruding projection (rib). This can be used when it is necessary to construct the coupling with ribs without creating thick sections, depending on the characteristics of the material used.

[0567] In other words, in each configuration of Figures 54(a) to (d), each top surface (143d, 147f, 148d1, 148d2, 149d), regardless of its shape, guides the brake engagement members (204, 208) toward the brake force receiving portion 143c. That is, each top surface, regardless of its shape, is a guide (inclined portion) for guiding the brake engagement members (204, 208) toward the brake force receiving portion 143c. At least a part of such a top surface (guide) is formed by the guide forming portion 143n.

[0568] Similar to the top surface, the shape of the pushback surface (pushback portion) 143k shown in Figure 52 can take various forms. For example, although the pushback portion (pushback surface) 143k in this modified example was a smoothly continuous helical slope, the pushback portion may have multiple surfaces or steps to form an incline. For example, as in the pushback portion 143k of Embodiment 1 shown in Figures 48(b) and 56(d), the pushback portion 143k may have two surfaces with different inclines. Also, although the pushback surface 143k was an uphill slope, it may have a locally downhill portion.

[0569] The drum coupling 143 may have either an overhang 143g or a pushback surface (pushback portion) 143k, or it may have both. As mentioned above, the drum coupling 143 of Embodiment 1 shown in Figures 48(b), 55(b), and 56(d) has a configuration that has both an overhang 143g and a pushback portion 143k. Normally, the drum coupling 143 can block the improper entry and proximity of the brake engagement members (204, 208) by the overhang 143g, but if it fails to block this, the pushback surface 143k pushes the brake engagement members (204, 208) back, moving them away from the coupling 143.

[0570] The drum coupling 143 has protruding shapes (rebound portion forming portion, second guide forming portion) 143m that constitute the push-back surface 143k (see Figures 79(b) and (c)).

[0571] The engaging portion 143i, the guide forming portion 143n, the projection shape 143m, and the overhang 143g (see Figure 79) may be referred to in any order as the first, second, third, and fourth shape portions, etc.

[0572] Next, Figures 54(e) and 73(d) show modified examples of the brake force receiving portion (second side surface).

[0573] The brake force receiving portion 143c described in Embodiment 1 shown in Figures 54(a), 1(a), and 55-57, as well as in other modified examples shown in Figures 52 and 54(b)-(d), had a shape that protruded downstream in the direction of rotation. This is because the shape of the brake force receiving portion 143c protruding downstream in the direction of rotation increases the stability of engagement when it engages with the brake engagement members (204, 208).

[0574] In other words, this shape generated a force that pulled the brake force receiving portion 143c towards the brake engagement members (204, 208) when they engaged. The brake force receiving portion 143c protruded downstream in the direction of rotation. Therefore, when the brake force engagement members (204, 208) came into contact with the brake force receiving portion 143c, a force was generated that pulled the brake force engagement members (204, 208) inward in the axial direction toward the drum coupling 143 and the photoreceptor drum 104. This stabilized the engagement between the brake force receiving portion 143c and the brake force engagement members (204, 208), making it difficult for the engagement to disengage.

[0575] As described above, the brake engagement members (204, 208) are configured to be movable in the axial direction relative to the drum drive coupling 180 (see Figures 67 and 68). However, when the drive transmission unit 203 is driving the drum coupling 143, if the brake engagement members (204, 208) move in the axial direction, the engagement state with the brake force receiving portion 143c may be dissolved or become unstable. Therefore, it is preferable that the brake force receiving portion 143c has a shape that stabilizes the engagement state with the brake engagement members (204, 208) and suppresses the axial movement of the brake engagement members (204, 208) when the drum up ring 143 is driven.

[0576] However, when the braking force required to be applied to the brake force receiving portion is small, or when the coefficient of friction of the brake force receiving portion is high, the engagement between the brake force receiving portion and the brake engagement members (204, 208) is inherently stable. Therefore, the protruding portion of the brake force receiving portion can be eliminated. Such a brake force receiving portion 144t is shown in Figures 54(e) and 73(d). In the modified drum coupling 143 shown in Figures 54(e) and 73(d), the brake force receiving portion 144c does not protrude toward the downstream side in the direction of rotation (arrow A).

[0577] On the other hand, it is also conceivable to implement measures to further stabilize the engagement state of the brake force receiving portion 144c with the brake engagement members (204, 208) in this shape.

[0578] To stabilize the engagement between the brake force receiving portion 144c and the brake engagement member, it is conceivable to attach an elastic member (elastic part) 144t, such as rubber, to the brake force receiving portion 144c, or to integrally mold the elastic part with the brake force receiving portion 144c. By increasing the coefficient of friction of the brake force receiving portion 144t, or by causing the brake engagement members (204, 208) to bite into the elastic part of the brake force receiving portion 144t, the engagement with the brake engagement members (204, 208) becomes less likely to disengage, and the engagement can be stabilized.

[0579] As a method to increase the frictional force of the brake force receiving portion 144c, it is also conceivable to use an adhesive material (adhesive material) instead of the elastic material 144t. For example, if double-sided tape (adhesive material) is applied to the surface of the brake force receiving portion 144c, its viscosity will increase the frictional force between the brake force receiving portion 144c and the brake engagement members (204, 208), making it more difficult for the engagement between the two to disengage. Alternatively, instead of using the elastic material 144t, it is also conceivable to increase the coefficient of friction of the brake force receiving portion 144c by surface treatment of the brake force receiving portion 144c.

[0580] Furthermore, the helical inclined surface 143d (see Figure 67) for guiding the brake engagement members (204, 208) should preferably have a low coefficient of friction in order to achieve smooth guidance. Therefore, even if a material with a high coefficient of friction is selected or surface treatment is applied to the brake force receiving portion 144c, it is preferable to avoid using such a material or surface treatment on the helical inclined surface 143d, rather than applying such treatment to the entire coupling. In other words, it is desirable that the coefficient of friction of the brake force receiving portion 144c be higher than that of the helical inclined surface 143d.

[0581] Furthermore, an elastic portion 144t may be provided in the brake force receiving portion 143c of the drum coupling 143, as shown in Figures 54(a) to (d).

[0582] Next, the preferred arrangement and dimensional relationships of the drum coupling 143 will be explained using Figure 101. Figure 101 is a front view of the drum coupling 143 of Embodiment 1. θ (theta) 11 is the value that represents the distance from the driving force receiving portion 143b to the braking force receiving portion 143c of the engaging portion 143i, expressed as an angle with the axis of the drum coupling 143 as the origin. In other words, it is the angle of the region of the downstream inclined portion 143d1.

[0583] Regarding the upper limit of θ11, it is desirable that θ11 be 90° or less, more preferably 80° or less. θ11 corresponds to the gap that occurs between the drum drive coupling 180 and the brake engagement members (204, 208) when the drum coupling engages with the drive transmission unit 203 (see Figure 64). In order to reliably sandwich the drive force receiving portion 143b and the brake force receiving portion 143c between the brake engagement members (204, 208) of the device body and the drum drive coupling 180, it is desirable that θ11 be 90° or less, more preferably 80° or less.

[0584] On the other hand, regarding the lower limit of θ11, it is possible to reduce θ11 by increasing the strength of the engaging portion 143i, such as by making the engaging portion 143i that forms the driving force receiving portion 143b and the brake force receiving portion 143c out of metal. As will be described in detail later, in the modified drum coupling shown in Figure 74, the thickness of the engaging portion 145i corresponding to the engaging portion 143i is made smaller than in this embodiment by making the drum coupling 143 out of metal. Considering such a configuration, the preferred condition for the lower limit of θ11 (Figure 101) is that θ11 is 1° or more, more preferably 2° or more, and even more preferably 8° or more. In this embodiment, θ11 is set to 30° or more, and θ11 is set to approximately 35°.

[0585] In order to increase the strength of the driving force receiving portion 143b and the braking force receiving portion 143c so that they can stably receive force, it is desirable to ensure that the angle θ11, which corresponds to the thickness of the engaging portion 143i, is of a certain size.

[0586] Converting θ11 to a length gives the thickness of the engaging portion 143i, that is, the distance measured along the rotational direction from the driving force receiving portion 143b to the braking force receiving portion 143c. A desirable range for this distance is 0.3 mm or more, more preferably 1 mm or more.

[0587] In Figure 101, θ12 represents the area occupied by the upstream slope (upstream guide, upstream inclined portion) 143d2 as an angle. Regarding the lower limit of θ12, it is desirable that the value of θ12 be at least half the value of θ11, and more preferably that the value of θ12 be at least the value of θ11. This is because the upstream slope 143d2 needs to have a length in the rotational direction necessary to guide the brake engagement members (204, 208) to the brake force receiving portion 143c by the upstream inclined portion 143d2.

[0588] The smaller θ11 is and the larger the slope angle of the upstream slope 143d2, the smaller the lower limit of θ12 can be.

[0589] Thus, the lower limit of θ12 depends on the magnitude of the value of θ11 and the angle of the upstream slope 143d2, but if we were to express it numerically, θ12 is 1° or more, more preferably 2° or more, even more preferably 8° or more, and even more preferably 30° or more. In this embodiment, θ12 was set to 60° or more.

[0590] Regarding the upper limit of θ12, it is possible to make θ12 relatively large, and it is possible to exceed 360°. However, preferably, θ12 is 360° or less, more preferably 270° or less, and in this embodiment, it was set to 180° or less. Specifically, θ12 was set to approximately 67°.

[0591] Configurations in which θ12 is larger than in this embodiment will be described later with reference to Figures 102 and 103.

[0592] θ13 is the sum of θ11 and θ12, and corresponds to the angle occupied by the entire helical inclined surface 143d. If θ13 is to be expressed numerically, it is desirable that θ13 be 2° or more, more preferably 8° or more. Furthermore, it is desirable that θ13 be 360° or less, and even more preferably 270° or less. In this embodiment, θ13 was set to be 180° or less. Specifically, θ13 was set to approximately 102°.

[0593] Figure 74 illustrates another modified example of the coupling 143.

[0594] Figure 74 shows a modified coupling, including an oblique view and a front view drawn from two different viewing directions.

[0595] The coupling 143 in this modified example has an engaging portion 145i having a driving force receiving portion 145b and a braking force receiving portion 145b, and a guide forming portion 145n having a helical inclined surface 145d. The engaging portion 145i and the guide forming portion 145n correspond to the engaging portion 143i and the guide forming portion 143n of the coupling 143 shown in Embodiment 1 (see Figure 79), but their shapes are slightly different.

[0596] In this modified example, the coupling 143 has an overhang 143g that contacts a second brake engagement member 208 (not shown), and the helical slope 145d is formed as a curved surface. This curved surface is approximately arc-shaped and is positioned to connect the inclination start point 143f to the brake force receiving portion 145c. In this modified example, the brake force receiving portion 145c does not have a shape that protrudes downstream in the rotational direction, so an elastic member (elastic part) 145t may be attached to the brake force receiving portion 145c as in Figure 54(e).

[0597] In this modified example (Figure 74), the helical slope 145d corresponds to the top surface of the upstream slope 143d2 in Example 1 (Figure 57).

[0598] On the other hand, in this modified example (Figure 74), the top surface (upper part) 145e of the engaging portion 145i (Figure 74(b)) corresponds to the downstream slope 143d1 of Embodiment 1 (Figure 57), but unlike the downstream slope 143d1, it is not inclined.

[0599] In other words, the downstream top surface 145e is connected to the upstream top surface (helical inclined surface 145d), but the inclination angles of the two surfaces are different at the boundary. The top surface 145e and the helical inclined surface 145d are not smoothly connected.

[0600] Furthermore, because the distance between the driving force receiving portion 145b and the braking force receiving portion 145c is small, the length of the top surface 145e measured along the direction of rotation is smaller (shorter) than the length of the downstream slope 143d1 in Figure 57. Also, as mentioned above, the top surface 145e is not inclined. In this modified example, the top surface 145e can also be considered as not being used as a guide.

[0601] However, even with this configuration, the spiral inclined surface 145d, which is the guide (inclined part), can guide the brake engagement members (204, 208) toward the brake force receiving part 145c.

[0602] Furthermore, a flat surface 145h is adjacent to the upstream of the helical slope 145d, and the helical slope 145d and the flat surface 145h are connected. This flat surface 145h can also be inclined in the same direction as the helical slope 145d to become part of the helical slope 145d. In addition, the drum coupling of this modified example may have an overhang 143g and a pushback surface 143k as described in Example 1 and another modified example of Example 1 (see Figures 1, 52, etc.).

[0603] Furthermore, regarding the shape of the drum coupling, the shape of the shaft portion 143j shown in Figure 1 can also be selected for design reasons. For example, Figure 75 shows a modified shape of the drum coupling. In the example in Figure 75, the diameter of the shaft portion 146j is the same as the diameter of the photoreceptor drum 104. The shaft portion 146j is rotatably supported by the drive-side cartridge cover member 116 (see Figure 15). Position restriction in the direction of arrow MB1 can be achieved, for example, using the shaft end face 146s. In this way, the shape of the shaft portion 146j can also be appropriately selected in accordance with the relationship with surrounding parts and the manufacturing method.

[0604] Another modified example of the drum coupling 143 is shown in Figures 76(b), (c), 78(a), (b), (c), and (d). These show a drum coupling in which the two coupling parts 143s and 143r have different shapes. Figures 76(b) and (c) are exploded views of the coupling 143, and in Figure 76(c), the drum drive coupling 180 and brake engagement member 208 on the device body side are also shown in addition to the exploded view. Figures 78(a) and (b) show perspective views of the drum coupling 143. Figures 78(c) and (d) show the engagement state of the brake engagement members (204, 208) and the drum drive coupling 180 with respect to the drum coupling 143.

[0605] In the coupling 143 shown in these figures, the engaging portion 143i of one coupling portion 143s does not have a brake force receiving portion 143c, but only a drive force receiving portion 143b. That is, the side surface 143y provided on the engaging portion 143i of the coupling portion 143s does not engage with the brake engaging members (204, 208). In contrast, the engaging portion 143i of the other coupling portion 143r has only a brake force receiving portion 143c and does not have a drive force receiving portion 143b. The side surface 143x of the engaging portion 143i of the coupling portion 143r does not engage with the drum drive coupling 180.

[0606] Furthermore, another example of an asymmetrical coupling 143 is shown in Figure 76(d). In this example, the coupling portion 143s has no side surface corresponding to the driving force receiving portion 143c.

[0607] The modified versions of the coupling 143 shown in Figures 76(b), (c) and 78(a), (b), (c), (d) receive driving force at only one point and braking force at only one point. Therefore, in order for the drum coupling to stably receive driving force and braking force, it is desirable to improve the accuracy of the fitting between the circular hole portion 143a and the positioning boss 180i of the drum drive coupling 180 (see Figure 51). In other words, it is desirable to reduce the gap between the two and improve the positional accuracy of the drum coupling 143 relative to the drive transmission unit 203, thereby ensuring stable and reliable engagement between the drive transmission unit 203 and the drum coupling 143.

[0608] Furthermore, Figure 77 shows another modified example of the drum coupling having one driving force receiving section and one braking force receiving section. The drum coupling 143 shown in Figure 77 has an upstream slope 143d2, a downstream slope 143d1, an overhang 143g, a driving force receiving section 143b, a braking force receiving section 143c, and only one extrusion surface 143k. Figure 77(a) is a perspective view of the drum coupling, and Figure 77(b) is a front view.

[0609] In addition, in the modified drum coupling 143 shown in Figure 77, any part of the slope 143d, the overhang 143g, the driving force receiving part 143b, the braking force receiving part 143c, and the extrusion surface 143k may be positioned at a location that is 180° symmetric (axially symmetric).

[0610] For example, as shown in Figure 96, the visor 143g of the drum coupling 143 shown in Figure 77 may be moved to a region S143g that is 180° symmetric, or the extruded surface 143k may be moved to a symmetric region S143k.

[0611] This is because both the drum drive coupling 180 and the brake engagement members (204, 208) have shapes that are 180° symmetrical.

[0612] Therefore, regardless of which of the two 180° symmetrical locations a single helical inclined surface 143d is positioned, that inclined surface 143d can act on the entire brake engagement member (204, 208). Similarly, the extruded surface 143k may be positioned in either of the two 180° symmetrical locations. The same applies not only to the visor 143g and the extruded surface 143k, but also to the brake force receiving portion 143c.

[0613] Furthermore, regardless of which of the two 180° symmetrical locations the drive force receiving portion 143b is positioned in, the drum drive coupling 180 can engage with the drive force receiving portion 143b.

[0614] The drum drive coupling 180 has two drive transmission surfaces 180d, and these two drive transmission surfaces 180d move integrally (Figure 45(a)). The brake engagement members (204, 208) each have two coupling engagement portions 204b and 208b, and all of these coupling engagement portions move integrally (see Figure 45(b)).

[0615] Thus, another modified example of the drum coupling 143 with an asymmetrical shape is as follows: One coupling portion 143s has an engaging portion 143i but no guide forming portion 143n, while the other coupling portion 143r has a guide forming portion 143n but no engaging portion 143i. Examples of such configurations are shown in Figures 97(a) and (b). Figure 97(a) is a perspective view of a modified drum coupling, and Figure 97(b) is a front view.

[0616] In the modified drum coupling shown in these figures, there is a guide forming portion 343n and one engaging portion 343i. The guide forming portion 343n forms a helical inclined surface (guide, top surface, inclined portion) 343d2. The engaging portion 343i forms a driving force receiving portion 343b and a helical inclined surface (guide, top surface, inclined portion) 343d1. The guide forming portion 343n and the engaging portion 343i are located on opposite sides of the axis L. Furthermore, in this modified example, the brake force receiving portion 343b is not located on the engaging portion 343i, but rather on the downstream end of the guide forming portion 343n in the rotational direction. In other words, the engaging portion 343i engages with the driving force applying member (drum drive coupling) 180, but does not engage with the brake force applying members (brake engaging members 204, 208).

[0617] Figures 99(a), (b), and (c) show the engagement process of the drum coupling and brake engagement members (204, 208) of this modified example in this order. For illustrative purposes, the drum drive coupling 180 of the drive transmission unit 203 is not shown.

[0618] As shown in Figure 99(a), when the second brake engaging member 208 comes into contact with the inclined surface 343d2 of the guide forming portion 343n, the second brake engaging member 208 begins to move downstream in the rotational direction and closer to the photoreceptor drum 104 in the axial direction.

[0619] As shown in Figure 99(b), when the second brake engaging member 208 reaches near the end of the upstream slope 343d2, the first brake engaging member 204 contacts the slope 343d1, which is the top surface of the engaging portion 343i. Subsequently, the brake engaging members (204, 208) continue to rotate, and as shown in Figure 99(c), the tip of the first brake engaging member 204 enters the space downstream of the engaging portion 343i. The first brake engaging member 204 reaches a position where it can engage with the brake force receiving portion 343c (see Figure 97(b)).

[0620] As mentioned above, in the modified drum coupling shown in Figures 97 and 99, any part of it can be moved to a position 180° symmetrically. For example, as shown in Figure 98(a), the engaging part 343i and the driving force receiving part 343b can be moved to positions S343i and S343b, respectively, which are 180° symmetrically. When the engaging part 343i is moved to position S343i, it has a shape similar to the modified drum coupling shown in Figure 77. Conversely, if a part of the drum coupling shown in Figure 77 is moved to a position 180° symmetrically, it will have a shape similar to the modified drum coupling shown in Figure 97.

[0621] As shown in Figure 98(a), in this modified example, if the engaging portion 343i is virtually positioned at a 180° symmetrical position S343i, the inclined surface 343d2 becomes adjacent to the virtually positioned engaging portion S343i. The upstream portion 343d2a of the inclined surface 343d2 extends from upstream to downstream in the rotational direction toward the virtually positioned engaging portion S343i and the virtually positioned driving force receiving portion S343b.

[0622] Figure 98(b) shows the angles θ41, θ42, θ51, and θ52 related to the dimensions of each part in this modified example.

[0623] θ41 is the angle of the region where the engaging portion 343i is located. θ42 is the angle of the region occupied by the helical inclined surface 343d2 of the guide forming portion 343n. θ51 is the angle representing the region from S343b, where the driving force receiving portion 343b is virtually positioned 180° symmetrically, to the braking force receiving portion 343c. θ52 is the angle of the region occupied by the portion 343d2a of the helical inclined surface 343d2, which is located upstream in the rotational direction from the position S343b of the virtually positioned driving force receiving portion.

[0624] θ41 is preferably 1° or more, more preferably 2° or more, and even more preferably 8° or more, in order to ensure the strength of the driving force receiving portion 343b.

[0625] θ51 corresponds to the angle of the gap between the brake engagement members (204, 208) and the drum drive coupling 180. Therefore, as described above, it is desirable that it be 80° or less.

[0626] Furthermore, since θ51 is greater than θ41, it is desirable that θ51 be 1° or more, more preferably 2° or more, and even more preferably 8° or more. Also, it is desirable that θ41 be 80° or less.

[0627] θ52 is the angle corresponding to θ12 in Figure 101, and the preferred range for θ52 is the same as for θ12. Similarly, θ42 is the angle corresponding to θ13 in Figure 101, so the preferred range for θ42 is the same as for θ13.

[0628] Furthermore, another modified example of the asymmetrical drum coupling is shown in Figures 100(a) and (b). This configuration is such that the upstream slope 143d2 of Embodiment 1 (see Figure 58, etc.) is divided and placed in two locations. That is, the upstream slope 143d2 is divided into an upstream portion 143d2a and a downstream portion 143d2b. The engaging portion 143i is adjacent to the downstream portion 143d2b of the upstream slope 143d2.

[0629] The dimensional relationships in this modified example are shown in Figure 100(b). Angle θ21 is the angle of the engaging portion 143i and corresponds to angle θ11 in Figure 101. The preferred angle for θ21 is the same as for angle θ11. θ22b is the angle occupied by the downstream portion 143d2b of the upstream slope 143d2, and θ22b is the angle occupied by the upstream portion 143d2a of the upstream slope 143d2.

[0630] Furthermore, let S143d2b be the region obtained by virtually moving the downstream portion 143d2b of the upstream slope 143d2 to a position 180° symmetrical. In this case, the angle between the virtual region S143d2b and the region occupied by the upstream portion 143d2a is θ32. Since θ32 corresponds to the angle θ12 in Figure 101, the preferred angle range for θ32 is equivalent to the preferred angle range for θ12.

[0631] Furthermore, the preferred angle ranges for θ22a and θ22b are the same as those for θ12.

[0632] Furthermore, another modification of the drum coupling will be described. The helical inclined surface 143d and the upstream inclined surface 143d2, which serve as guides or upstream guides, can be made longer than those in the drum coupling of Example 1 (Figure 1, etc.). Such examples are shown in Figures 102 and 103. In the drum couplings shown in these figures, the helical inclined surface 443d2, which corresponds to the upstream inclined surface 143d2, is positioned to extend beyond 360°. In other words, the helical inclined surface 443d2 is positioned to extend more than one full turn.

[0633] In this embodiment, the engaging portion 443i, which corresponds to the engaging portion 143i in Embodiment 1, is positioned separately from the inclined surface 443d2. The engaging portion 443i has a brake force receiving portion 443c1 and a driving force receiving portion 443b. A brake force receiving portion 443c2 is also positioned near the end of the helical inclined surface 443d2. The brake force receiving portions 443c1 and 443c2 are positioned 180° symmetrically.

[0634] Figures 103(a), (b), and (c) show the engagement process of the drum coupling and brake engagement member of this modified example in chronological order. The drum drive coupling 180 is not shown for illustrative purposes.

[0635] As shown in Figure 103, the brake engagement members (204, 208) rotate more than one full turn by being guided by the helical inclined surface 443d2. Thus, it is possible to make the length of the guide, the helical inclined surface 443d2, larger than 360°. However, if the helical inclined surface 443d2 is long, the time required for the brake engagement members (204, 208) to pass through the helical inclined surface 443d2 may increase, or the speed at which the brake engagement members (204, 208) move along the helical inclined surface 443d2 may decrease. To address this, when engaging the drive transmission unit 203 with the coupling 143, it may be necessary to slow down the rotational speed of the drive transmission 203 to ensure that the brake engagement members (204, 208) have sufficient time to pass through the helical inclined surface 443d2.

[0636] In order to smoothly engage the drive transmission unit 203 with the drum coupling 143 while the drive transmission unit 203 is rotating at high speed, it is desirable to shorten the time it takes for the brake engaging members (204, 208) to pass over the helical inclined surface 443d2. From this viewpoint, it is more preferable to set the length of the helical inclined surface (inclined portion, guide) 443d2 to 360° or less, and even more preferable to set it to 270° or less.

[0637] As described above, a modified version of the drum coupling 143 in Example 1, in which the shape is changed to an asymmetrical shape, can also be used.

[0638] However, a configuration in which the coupling 143 has two drive force receiving portions 143b and two brake force receiving portions 183c located 180° apart, as shown in the drum coupling 143 of Embodiment 1 in Figures 1 and 58, is more preferable because it stabilizes the engagement state of the drive transmission unit 203 with respect to the coupling 143 and the transmission state of the drive force. The coupling 143 can receive the drive force at two symmetrically arranged points, and similarly, the brake force can be received at two symmetrically arranged points. Therefore, it becomes easier to maintain a balance of forces applied to the coupling 143.

[0639] Furthermore, in the drum coupling 143 of the above-described embodiment 1 (see Figure 1), the various shaped parts of the coupling (engaging part, guide forming part, overhang, etc.) were in a specific arrangement relationship. However, it is also conceivable that these arrangement relationships could be changed by making any part of the coupling 143 movable.

[0640] As an example, Figures 104 to 106 show a configuration in which the engaging portion 243i is movable relative to the rest of the drum coupling 143, specifically a configuration in which it can move radially back and forth. As shown in Figure 105, the drum coupling 143 has two openings 243p formed therein, and the engaging portion 243i is disclosed so as to be partially exposed from inside the drum coupling 143 through these openings 243p.

[0641] As shown in Figure 105(a), the two engaging portions 243i are supported by the guide 199a of the support member 199, which is located inside the drum coupling. Furthermore, the engaging portions 243i are configured to be movable radially along the guide 199a, but are biased radially inward by the tension spring 200.

[0642] Therefore, when the cartridge is not in use, the two engaging portions 243i are retracted inside the drum coupling, as shown in Figures 104(a) and (c). On the other hand, when attempting to mount the cartridge onto the image forming apparatus body, the positioning boss 180i enters the drum coupling and contacts the engaging portions 243i, as shown in Figure 106(a). Furthermore, as the positioning boss 180i enters the drum coupling 143, the engaging portions 243i are pushed radially outward by the positioning boss 180i. As a result, as shown in Figures 104(b) and (d), a portion of the engaging portions 243i advances toward the outside of the drum coupling 143.

[0643] In this state, both sides of the engaging portion 243i, namely the driving force receiving portion 243b and the braking force receiving portion 243c, are exposed and are in a state where they can receive driving force and braking force from the image forming apparatus body, respectively.

[0644] Thus, the arrangement and shape of the coupling 143 are not fixed and may vary or change. For example, the drum coupling, which is vulnerable to external impacts, can be retracted and protected when the cartridge is not in use.

[0645] If a part of the coupling 143 is movable, the state of the coupling 143 when it is actually used, that is, when the cartridge and drum unit are mounted on the image forming apparatus body and the coupling 143 engages with the drive transmission unit 203, can be considered as the reference state. In this reference state, the shape of the coupling 143 and the arrangement of its parts should be configured to satisfy the desired conditions described above.

[0646] Furthermore, Figures 107 and 108 show another modified example of the drum coupling 143 in which a part of the drum coupling 143 is configured to deform and move. In the previously described modified example (see Figure 105), the engaging portion 243i was configured to move radially, but in this modified example, the engaging portion 643i is configured to move axially. Figure 107(a) shows the engaging portion 643i retracted into the drum coupling, and Figure 107(b) shows the engaging portion 643i advanced toward the outside of the drum coupling, away from the photoreceptor drum. Figure 107(c) is an exploded perspective view of the drum unit in this modified example.

[0647] Figures 108(a) and (b) show cross-sectional views of the drum unit. Figure 108(a) shows the drum unit before it is mounted on the main body of the device, and (b) shows it after it has been mounted.

[0648] When the drum unit is mounted on the main body of the device, the positioning boss 180i provided on the drive transmission unit comes into contact with the operating member 698 of the drum coupling. As a result, as shown in Figure 108(b), the operating member 698 moves inward in the axial direction (to the right in the figure). Along with this movement of the operating member 698, the interlocking member 698 is pushed radially outward inside the drum coupling. As the interlocking member 698 moves radially outward, the engaging portion 643i is pressed radially outward by the interlocking member 698. As a result, the engaging portion 643i changes from a state where it is retracted inside the drum unit (Figures 107(a), 108(a)) to a state where a part of it is exposed to the outside (Figures 107(b), 108(b)).

[0649] When a portion of the drum coupling is made movable in this manner, the direction of movement may be radial or axial. The portion of the drum coupling may move in both the radial and axial directions, or it may move in the rotational direction.

[0650] Next, Figures 109 and 110 describe another modified example of the drum coupling. Similar to the two modified examples described above, the drum coupling 1043 in this modified example is also configured such that a part of it deforms and moves.

[0651] Figure 109(a) is an exploded perspective view of the drum unit of this modified example. (b) shows the engagement portion 1043i of the drum coupling extended outward from the drum unit, and (c) shows the engagement portion 1043i partially retracted inward.

[0652] In this modified example, before the drum unit is mounted on the main body of the device, the engaging portion 1043i is in a protruding (extended) state, as shown in Figure 109(b). On the other hand, after the drum unit is mounted on the main body of the device, the engaging portion 1043i changes to a retracted state, as shown in Figure 109(c).

[0653] Figures 110(a) and (b) show cross-sectional views of the drum unit. (a) shows the drum unit before it is fully mounted to the main body of the device, and (b) shows the drum unit after it has been fully mounted.

[0654] As shown in Figure 109(a), the engaging member 1043 is arranged inside the drum coupling 143 so as to be movable in the axial direction. The engaging member 1043 is biased (pressed) outward in the axial direction by a compression coil spring 1020 located inside the drum coupling 143, so that an engaging portion 1043i, which is part of the engaging member 1043, is exposed to the outside of the drum coupling 143.

[0655] The engaging member 1043 has an operating portion 1043p on its rotation axis. As shown in Figure 110(b), when the drum unit is mounted on the device body, the operating portion 1043p is pressed by the positioning boss 180i, causing the engaging member 1043 and the engaging portion 1043i to retract inward in the axial direction.

[0656] In the three modifications described above, an action part that can be acted upon from outside the cartridge is placed inside the coupling 143, and this action part is operated by the positioning boss 180i to change the shape of the coupling 143. However, it is also conceivable to place the action part for changing the shape of the coupling 143 in a location other than inside the coupling 143.

[0657] As explained above, various shapes and forms of couplings can be selected depending on design reasons related to their arrangement, production reasons considering molds for coupling production, and purposes such as coupling protection.

[0658] Furthermore, in all three variations of the drum coupling described above, the engaging portion, which includes the driving force receiving portion and the braking force receiving portion, moved relative to the other parts. However, the helical slope or overhang portion may also be movable relative to the other parts.

[0659] Furthermore, although the cartridge 100 described above includes a photosensitive drum and a developing roller, the configuration of the cartridge 100 is not limited to this configuration. For example, a configuration in which the cartridge 100 has a photosensitive drum but does not have a developing roller is also conceivable. One example of such a configuration is in which the cartridge 100 consists only of a drum holding unit 108 (see Figure 19).

[0660] In Example 1 and its various modifications, the drum coupling 143 is positioned near one end (the drive end) of the photoreceptor drum 104 and is press-fitted into the cavity formed by the photoreceptor drum 104. As a result, driving force can be transmitted from the drum coupling 143 to the end of the photoreceptor drum 104. However, the method of connecting the drum coupling 143 and the photoreceptor drum 104 is not limited to press-fitting. Also, in the above example, the drum coupling 143 and the photoreceptor drum 104 formed a drum unit 103 together, but the drum coupling 143 and the photoreceptor drum 104 may be separate and not constitute a drum unit.

[0661] In other words, as long as the drum coupling 143 is operationally connected to the photoreceptor drum 104, that is, connected in a manner that allows for drive transmission, other connection methods can be used, and the coupling 143 and the photoreceptor drum 104 do not necessarily constitute the same unit.

[0662] For example, one or more intermediate members may be interposed between the coupling 143 and the photoreceptor drum 104. In this case, the drum coupling 143 can be considered to be indirectly connected to the drive-side end of the photoreceptor drum 104 via the intermediate members. The drum coupling 143 operates the photoreceptor drum 104 via the intermediate members by rotating itself.

[0663] For example, a gear could be attached to the end of the photoreceptor drum 104, and a gear could also be formed on the outer surface of the drum coupling 143. In this way, the gear of the coupling 143 and the gear of the photoreceptor drum 104 could be directly meshed, or another idler gear could be interposed between the two gears to transmit driving force from the drum coupling 143 to the photoreceptor drum 104.

[0664] In addition to using gears as intermediate components, another method is to connect a drive transmission belt to the drum coupling 143 and the photoreceptor drum 104 to serve as an intermediate component.

[0665] Alternatively, the drive-side end of the photoreceptor drum 104 and the drum coupling 143 can be connected using an Oldham coupling as an intermediate member. In this case, the drum unit 103 can be considered as a unit having the photoreceptor drum 104, an Oldham coupling (intermediate member), and the drum coupling 143.

[0666] Thus, the connection method between the photoconductor drum 104 and the drum coupling 143 may be direct or indirect. Furthermore, the photoconductor drum 104 and the drum coupling 143 may be unitized to form a drum unit 103, or the photoconductor drum 104 and the drum coupling 143 may be located separately within the cartridge and not form a single unit.

[0667] However, if the coupling 143 and the photoreceptor drum 104 form a drum unit 103 that can rotate integrally, or if the coupling 143 is directly connected to the end of the photoreceptor drum 104, the drive (rotation) of the coupling 143 can be transmitted to the photoreceptor drum 104 with greater precision, which is preferable.

[0668] In this embodiment, the axes of the drum coupling 143 and the photoreceptor drum 104 coincide. That is, the drum coupling 143 and the photoreceptor drum 104 are aligned along the same axis of rotation L (see Figure 1). However, when the drum coupling 143 and the photoreceptor drum 104 are connected indirectly, the positions of their axes may differ.

[0669] In any case, the cartridge can be driven stably by engaging the coupling 143 with the drive transmission unit 203 provided on the main body of the device.

[0670] An example of a modified cartridge configuration will be further explained using the following second embodiment. <<Embodiment 2>> <Overall configuration of the image forming apparatus 800>

[0671] The overall configuration of the electrophotographic image forming apparatus 800 (hereinafter referred to as the image forming apparatus 800) according to this embodiment will be described with reference to Figure 82. Figure 82 is a schematic diagram of the image forming apparatus 800 according to this embodiment. In this embodiment, the process cartridge 701 and the toner cartridge 713 are detachably attached to the main body of the image forming apparatus 800.

[0672] In this embodiment, the configuration and operation of the first to fourth image forming units are substantially the same, except that the color of the formed image differs. Therefore, in the following description, the subscripts Y to K will be omitted unless otherwise necessary, and a general explanation will be given.

[0673] The first to fourth process cartridges 701 are arranged horizontally. Each process cartridge 701 consists of a cleaning unit 704 and a developing unit 706. The cleaning unit 704 has a photoreceptor drum 707 as an image carrier, a charging roller 708 as a charging means for uniformly charging the surface of the photoreceptor drum 707, and a cleaning blade 710 as a cleaning means. The developing unit 706 has a developing roller 711 and a developer T (hereinafter referred to as toner), and has a developing means for developing an electrostatic latent image on the photoreceptor drum 707. The cleaning unit 704 and the developing unit 706 are supported so as to be able to swing relative to each other. The first process cartridge 701Y contains yellow (Y) toner in the developing unit 706, similarly the second process cartridge 701M contains magenta (M), the third process cartridge 701C contains cyan (C), and the fourth process cartridge 701K contains black (K) toner.

[0674] The process cartridge 701 is detachable from the image forming apparatus 800 via mounting means such as mounting guides and positioning members provided on the image forming apparatus 800. A scanner unit 712 for forming an electrostatic latent image is located below the process cartridge 701. Furthermore, a waste toner transport unit 723 is located behind the process cartridge 701 in the image forming apparatus 800 (downstream in the direction of attachment / detachment of the process cartridge 701).

[0675] The first to fourth toner cartridges 713 are arranged horizontally below each process cartridge 701 in an order corresponding to the toner color contained in each process cartridge 701. Specifically, the first toner cartridge 713Y contains yellow (Y) toner, the second toner cartridge 713M contains magenta (M), the third toner cartridge 713C contains cyan (C), and the fourth toner cartridge 713K contains black (K) toner. Each toner cartridge 713 then replenishes the toner in the process cartridge 701 containing the toner of the same color.

[0676] The toner cartridge 713 is replenished when a toner level detection unit located in the main body of the image forming apparatus 800 detects that the toner level in the process cartridge 701 is insufficient. The toner cartridge 713 is detachable from the image forming apparatus 800 via mounting means such as mounting guides and positioning members provided in the image forming apparatus 800. A detailed explanation of the process cartridge 701 and the toner cartridge 713 will be given later.

[0677] Below the toner cartridge 713, the first to fourth toner transport devices 714 are arranged corresponding to each toner cartridge 713. Each toner transport device 714 transports the toner received from each toner cartridge 713 upwards and supplies toner to each developing unit 706.

[0678] An intermediate transfer unit 719, which serves as an intermediate transfer body, is provided above the process cartridge 701. The intermediate transfer unit 719 is positioned approximately horizontally with the primary transfer section S1 side facing downwards. The intermediate transfer belt 718, which faces each photoreceptor drum 707, is a rotatable, endless belt and is stretched over a plurality of tension rollers. On the inner surface of the intermediate transfer belt 718, primary transfer rollers 720 are positioned to form the primary transfer section S1 with each photoreceptor drum 707 via the intermediate transfer belt 718. A secondary transfer roller 721, which is a secondary transfer member, is in contact with the intermediate transfer belt 718 and forms the secondary transfer section S2 with the roller on the opposite side via the intermediate transfer belt 718. Furthermore, an intermediate transfer belt cleaning unit 722 is positioned on the side opposite to the secondary transfer section S2 in the left-right direction (the direction in which the secondary transfer section S2 and the intermediate transfer belt are stretched).

[0679] Above the intermediate transfer unit 719, a fixing unit 725 is positioned. The fixing unit consists of a heating unit 726 and a pressure roller 727 that presses against the heating unit 726. The top surface of the device body has an output tray 732, and a waste toner collection container 724 is positioned between the output tray 732 and the intermediate transfer unit 719. Furthermore, a paper feed tray 702 for accommodating the recording material 703 is positioned at the very bottom of the device body.

[0680] The recording material 703 is a material on which the toner image from the main body of the device is transferred and fixed. An example of the recording material 703 is paper. <Image Forming Process>

[0681] Next, the image forming operation in the image forming apparatus 800 will be explained using Figures 82 and 83.

[0682] During image formation, the photoreceptor drum 707 is driven to rotate at a predetermined speed in the direction of arrow A in Figure 83. The intermediate transfer belt 718 is driven to rotate in the direction of arrow B in Figure 82 (forward of the rotation of the photoreceptor drum 707).

[0683] First, the surface of the photoreceptor drum 707 is uniformly charged by the charging roller 708. Next, the surface of the photoreceptor drum 707 is scanned and exposed by laser light emitted from the scanner unit 712, forming an electrostatic latent image on the photoreceptor drum 707 based on image information. The electrostatic latent image formed on the photoreceptor drum 707 is developed as a toner image by the developing unit 706. At this time, the developing unit 706 is pressurized by a developing pressure unit (not shown) provided in the main body of the image forming apparatus 800. Then, the toner image formed on the photoreceptor drum 707 is primary transferred onto the intermediate transfer belt 718 by the primary transfer roller 720.

[0684] For example, when forming a full-color image, the above-described process is carried out sequentially in the first to fourth primary transfer sections, which are the image forming sections S701Y to S701K, so that toner images of each color are sequentially superimposed on the intermediate transfer belt 718.

[0685] Meanwhile, the recording material 703 contained in the paper feed tray 702 is fed at a predetermined control timing and transported to the secondary transfer section S702 in synchronization with the movement of the intermediate transfer belt 718. Then, the four-color toner image on the intermediate transfer belt 718 is transferred collectively onto the recording material 703 by the secondary transfer roller 721, which is in contact with the intermediate transfer belt 718 via the recording material 703.

[0686] Subsequently, the recording material 703 on which the toner image has been transferred is transported to the fixing unit 725. In the fixing unit 725, the recording material 703 is heated and pressurized, fixing the toner image to the recording material 703. After that, the fixed recording material 703 is transported to the discharge tray 732, completing the image forming operation.

[0687] Furthermore, any primary transfer residue (waste toner) remaining on the photoreceptor drum 707 after the primary transfer process is removed by the cleaning blade 710. Any secondary transfer residue (waste toner) remaining on the intermediate transfer belt 718 after the secondary transfer process is removed by the intermediate transfer belt cleaning unit 722. The waste toner removed by the cleaning blade 710 and the intermediate transfer belt cleaning unit 722 is transported by a waste toner transport unit 723 provided in the main body of the apparatus and accumulated in the waste toner collection container 724. The image forming apparatus 800 can also form monochrome or multicolor images using only one or several desired image forming units. <Process Cartridge>

[0688] Next, the overall configuration of the process cartridge 701 mounted in the image forming apparatus 800 according to this embodiment will be described using Figures 83, 84, and 85. Figure 83 is a schematic cross-sectional view of the process cartridge 701 mounted in the image forming apparatus 800, in a state (position) where the photoreceptor drum 707 and the developing roller 711 are in contact, as seen from the Z direction. Figure 84 is a perspective view of the process cartridge 701 as seen from the front (upstream side in the process cartridge mounting / detachment direction). Figure 85 is a perspective view of the process cartridge 701 as seen from the rear (downstream side in the process cartridge mounting / detachment direction).

[0689] The process cartridge 701 is formed from a cleaning unit 704 and a developing unit 706. The cleaning unit 704 and the developing unit 706 are pivotably coupled around a rotating support pin 730.

[0690] The cleaning unit 704 has a cleaning frame 705 that supports various components within the cleaning unit 704. In addition to the photoreceptor drum 707, the charging roller 708, and the cleaning blade 710, the cleaning unit 704 also has a waste toner screw 715 that extends in a direction parallel to the rotation axis of the photoreceptor drum 707. Cleaning bearing units 733, which are equipped with a cleaning gear train 731 for rotatably supporting the photoreceptor drum 707 and transmitting drive from the photoreceptor drum 707 to the waste toner screw 715, are disposed at both longitudinal ends of the cleaning frame 705.

[0691] The charging roller 708, provided on the cleaning unit 704, is biased in the direction of arrow C by charging roller pressure springs 736 located at both ends toward the photoreceptor drum 707. The charging roller 708 is provided to move in accordance with the photoreceptor drum 707, and when the photoreceptor drum 707 is rotated in the direction of arrow A during image formation, it rotates in the direction of arrow D (forward of the rotation of the photoreceptor drum 707).

[0692] The cleaning blade 710 provided in the cleaning unit 704 consists of an elastic member 710a for removing transfer residue toner (waste toner) remaining on the surface of the photoreceptor drum 707 after primary transfer, and a support member 710b for supporting the elastic member 710a. The waste toner removed from the surface of the photoreceptor drum 707 by the cleaning blade 710 is contained in a waste toner storage chamber 709 formed by the cleaning blade 710 and the cleaning frame 705. The waste toner contained in the waste toner storage chamber 709 is transported toward the rear of the image forming apparatus 800 (downstream in the direction of attachment / detachment of the process cartridge 701) by a waste toner transport screw 715 installed in the waste toner storage chamber 709. The transported waste toner is discharged from the waste toner discharge section 735 and handed over to the waste toner transport unit 723 of the image forming apparatus 800.

[0693] The developing unit 706 has a developing frame 716 that supports various components within the developing unit 706. The developing frame 716 is divided into a dev...

Claims

A cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the main assembly including a driving force application member and a braking force application member, the cartridge comprising: a casing; a photosensitive drum rotatably supported by the casing; a coupling connected with the photosensitive drum so as to be capable of drive transmission, wherein the coupling including, a driving force receiving portion adapted to receive a driving force for rotating the coupling by engagement with the driving force application member, and a braking force receiving portion adapted to receive a braking force for applying a load against rotation of the coupling, by engagement with the braking force application member, and a guide adapted to move the braking force application member relative to the driving force application member,wherein the casing includes a first end portion and a second end portion opposite from the first end portion,wherein the photosensitive drum is rotatably supported by the first end portion and the second end portion,wherein the coupling is disposed adjacent to the first end portion of the casing,wherein a distance measured from the second end portion of the casing to the guide along an axial direction of the coupling decreases toward downstream in the rotational moving direction,wherein the guide has a portion more remote from the second end portion of the casing than the driving force receiving portion in the axial direction of the coupling, andwherein at least a part of the driving force receiving portion is more remote from an axis of the coupling than the remote portion of the guide in a radial direction of the coupling. A cartridge according to Claim 1, wherein the guide is configured to rotate the braking force application member relative to the driving force application member. . A cartridge according to Claim 1 , wherein the guide the braking force application member is configured to move the braking force application member relative to the driving force application member toward downstream in a rotational moving direction of the coupling member. A cartridge according to Claim 1, wherein the guide is configured to move the braking force application member away from the driving force application member. A cartridge according to Claim 1, wherein the guide is configured to permit the driving force receiving portion to enter between the braking force application member and the driving force application member by moving the braking force application member from the driving force application member. A cartridge according to Claim 1, wherein the guide is configured to guide the braking force application member toward the braking force receiving portion. A cartridge according to Claim 1, wherein the guide has a portion extending from upstream towards downstream in the rotational moving direction of the coupling toward the driving force receiving portion. A cartridge according to Claim 1, wherein the guide has a portion provided between the driving force receiving portion and the braking force receiving portion. A cartridge according to Claim 1, wherein the coupling is provided with opening coaxial with the axis of the coupling. A cartridge according to Claim 9, wherein the opening of the coupling is configured to engage with a positioning portion of the driving force application member to position the coupling relative to the driving force application member. A cartridge according to Claim 9, wherein the guide extends in the rotational moving direction of the coupling around the opening. A cartridge according to Claim 1, wherein the coupling includes a blocking portion for blocking the braking force application member from approaching toward the coupling in the axial direction of the coupling. A cartridge according to Claim 12, wherein the blocking portion is configured to block the braking force application member from approaching toward the coupling in a state that the braking force application member is close to the driving force application member. A cartridge according to Claim 12, wherein the blocking portion overhangs outwardly in a radial direction of the coupling.   A cartridge according to Claim 12, wherein the blocking portion is adjacent to the guide at a position upstream of the guide in the rotational moving direction of the coupling. A cartridge according to Claim 12, wherein the blocking portion is provided so as to cover a space provided downstream of the braking force receiving portion in the rotational moving direction.  A cartridge according to Claim 1, wherein the coupling includes a push-back portion configured to make the braking force application member away from the coupling in the axial direction. A cartridge according to Claim 17, wherein a distance measured from the second end portion of the casing to the push-back portion along the axial direction of the coupling increases toward downstream in the rotational moving direction of the coupling. A cartridge according to Claim 17 , wherein the push-back portion is disposed adjacent to the guide upstream of the guide in the rotational moving direction of the coupling. A cartridge according to Claim 1, wherein at least a part of the coupling is movable.  A cartridge according to Claim 20, wherein by mounting the cartridge to a main assembly of the image forming apparatus, at least a part of the coupling moves. A cartridge according to Claim 1, wherein the coupling is directly connected with an end portion of the photosensitive drum. A cartridge according to Claim 1, wherein the photosensitive drum is rotatably supported by the casing by way of the coupling. A cartridge according to Claim 1, further comprising: a charging roller for charging the photosensitive drum, toner accommodated in the casing, a development roller for developing a latent image formed on the photosensitive drum with the toner. A cartridge according to any one of claims 1 - 24, wherein at least a part of the braking force receiving portion overhangs toward downstream in a rotational moving direction of the coupling member.A cartridge according to Claim 1, wherein at least a part of the braking force receiving portion has a friction coefficient that is greater than a friction coefficient of the guide.An electrophotographic image forming apparatus comprising a main assembly including the driving force application member and the braking force application member; and a cartridge according to Claim 1. A drum unit detachably mountable to a main assembly of an image forming apparatus, the main assembly including a driving force application member and a braking force application member, the drum unit comprising: a photosensitive drum; a coupling connected with the photosensitive drum so as to is capable of drive transmission, wherein the coupling including, a driving force receiving portion adapted to receive driving force for rotating the coupling by engagement with the driving force application member, and a braking force receiving portion adapted to receive a braking force for applying a load against rotation of the coupling, by engagement with the braking force application member, and a guide adapted to move the braking force application member relative to the driving force application member,wherein the photosensitive drum includes a first end portion and a second end portion opposite from the first end portion,wherein the coupling is disposed adjacent to the first end portion of the photosensitive drum,wherein a distance measured from the second end portion of the photosensitive drum to the guide along an axial direction of the coupling decreases toward downstream in the rotational moving direction,wherein the guide has a portion more remote from the second end portion of the photosensitive drum than the driving force receiving portion in the axial direction of the coupling, andwherein at least a part of the driving force receiving portion is more remote from an axis of the coupling than the remote portion of the guide in a radial direction of the coupling. A drum unit according to Claim 28, wherein the guide is configured to rotate the braking force application member relative to the driving force application member. A drum unit according to Claim 28 , wherein the guide is configured to move the braking force application member relative to the driving force application member toward downstream in the rotational moving direction of the coupling member. A drum unit according to Claim 28, wherein the guide is configured to make the braking force application member away from the driving force application member. A drum unit according to Claim 28, wherein the guide is configured to permit the driving force receiving portion to enter between the braking force application member and the driving force application member by making the braking force application member away from the driving force application member. A drum unit according to Claim 28, wherein the guide is configured to guide the braking force application member toward the braking force receiving portion. A drum unit according to Claim 28, wherein the guide has a portion extending from upstream to downstream toward the driving force receiving portion in the rotational moving direction of the coupling. A drum unit according to Claim 28, wherein the guide has a portion disposed between the driving force receiving portion and the braking force receiving portion. A drum unit according to Claim 28, wherein the coupling is provided with an opening coaxial with an axis thereof. A drum unit according to Claim 36, wherein the opening of the coupling is configured to engage with a positioning portion of the driving force application member to position the coupling relative to the driving force application member. A drum unit according to Claim 36, wherein the guide extends in the rotational moving direction of the coupling around the opening.  A drum unit according to Claim 28, wherein the coupling includes a blocking portion for blocking the braking force application member from approaching the coupling in the axial direction of the coupling. A drum unit according to Claim 39, wherein the blocking portion is configured to block the braking force application member from approaching toward the coupling in a state that the braking force application member is close to the driving force application member. A drum unit according to Claim 39, wherein the blocking portion overhangs outwardly in a radial direction of the coupling. A drum unit according to Claim 39, wherein the blocking portion is adjacent to the guide at a position upstream of the guide in the rotational moving direction of the coupling. A drum unit according to Claim 39, wherein the blocking portion is provided so as to cover a space provided downstream of the braking force receiving portion in the rotational moving direction.  A drum unit according to claim 28, wherein the coupling includes a push-back portion configured to make the braking force application member away from the coupling in the axial direction.  A drum unit according to Claim 44, wherein a distance measured from the second end portion of the photosensitive drum to the push-back portion along the axial direction of the coupling increases toward downstream in the rotational moving direction of the coupling. A drum unit according to Claim 44, wherein the push-back portion is disposed adjacent to the guide upstream of the guide in the rotational moving direction of the coupling. A drum unit according to Claim 28, wherein at least a part of the coupling is movable. A drum unit according to Claim 47, wherein by mounting the drum unit to a main assembly of the image forming apparatus, at least a part of the coupling moves. A drum unit according to any one of Claims 28 - 47, wherein at least a part of the braking force receiving portion overhangs toward downstream in a rotational moving direction of the coupling member.A drum unit according to Claim 28, wherein at least a part of the braking force receiving portion has a friction coefficient that is greater than a friction coefficient of the guide.

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