Drum unit, drive transmission unit, cartridge, and electrophotographic image forming apparatus

Abstract

The invention relates to a drum unit, a drive transmission unit, a cartridge, and an electrophotographic image forming apparatus. The present invention enables engagement between the coupling member and the drive transmission member. The drum unit includes: a photosensitive drum; and a coupling member disposed adjacent to an end portion of the photosensitive drum and connected to the photosensitive drum so as to be able to transmit a driving force to the photosensitive drum. The coupling member is configured to be tiltable with respect to a rotation axis of the photosensitive drum, and decreases an inclination angle with respect to the photosensitive drum as the rotation is driven.

Description

[0001] This application is a divisional application of invention patent application 202080042378.1, filed on June 9, 2020, and entitled “Drum unit, drive transmission unit, box and electronic photographic imaging device”. Technical Field

[0002] The present invention relates to a drum unit, a drive transmission unit, a box and an electronic photographic imaging device.

[0003] Electrophotographic image forming apparatus (image forming apparatus) forms an image on a recording material by using an electrophotographic image forming process. For example, it includes an electrophotographic copier, an electrophotographic printer (LED printer, laser printer, etc.), a facsimile machine, a word processor, etc.

[0004] The cartridge is detachably mounted in the main assembly of the electrophotographic image forming apparatus. The drum unit is a unit including the photosensitive drum. The drive transmission unit is a unit including the coupling member. Background Art

[0005] In an electrophotographic image forming apparatus (hereinafter also referred to simply as an "image forming apparatus"), an electrophotographic photosensitive member (i.e., a photosensitive drum (electrophotographic photosensitive drum)) as an image bearing member, which is generally a drum type, is uniformly charged. Next, an electrostatic latent image (electrostatic image) is formed on the photosensitive drum by selectively exposing the charged photosensitive drum. Then, the electrostatic latent image formed on the photosensitive drum is developed into a toner image using a toner as a developer. Then, the toner image formed on the photosensitive drum is transferred onto a recording material (such as a recording sheet or a plastic sheet), and the toner image transferred onto the recording material is heated or pressurized to fix the toner image, thereby performing an image recording operation.

[0006] Such an image forming apparatus generally requires toner replenishment and maintenance of various processing devices. In order to facilitate such toner replenishment and maintenance, a photosensitive drum, a charging device, a developing device, a cleaning device, etc. are integrated in a frame to form a cartridge that can be mounted to and removed from the main assembly of the image forming apparatus, and such cartridges have been put into practical use.

[0007] If some parts of the unit of the image forming apparatus can be mounted in and removed from the apparatus main assembly like such a cartridge, a part of the maintenance of the apparatus can be performed by the user himself without relying on a service person in charge of after-sales service. Therefore, the operability of the apparatus can be significantly improved, and an image forming apparatus having excellent usability can be provided. Therefore, such a cartridge method is widely used in image forming apparatuses.

[0008] As an example of a cartridge of a unit that can be detachably mounted, a process cartridge in which a photosensitive drum and a process device acting on the photosensitive drum are integrated (into a cartridge) is known. In the process cartridge, a structure is widely used in which a coupling member is provided at the free end of the photosensitive drum so as to transmit a driving force from a main assembly of the device to the photosensitive drum (Japanese Patent Application Publication No. 2017-223802). Summary of the invention

[0009] [Problems to be solved by the invention]

[0010] The present invention provides a further development of the above mentioned prior art.

[0011] [Methods used to solve the problem]

[0012] The typical structure disclosed in the present application is a drum unit that can be used for a box, the drum unit comprising: a photosensitive drum; and a connecting member, which is arranged adjacent to the end of the photosensitive drum and is connected to the photosensitive drum so as to be able to transmit a driving force; wherein the connecting member is tiltable relative to the rotation axis of the photosensitive drum, and the inclination angle relative to the rotation axis of the photosensitive drum decreases with the rotational driving operation.

[0013] Another typical structure disclosed in the present application is a drive transmission unit that can be installed on the main component of an electronic photographic imaging device, and the drive transmission unit includes: a connecting member; and a supporting member for supporting the connecting member; wherein the connecting member can be tilted relative to the rotation axis of the supporting member, and the inclination angle relative to the rotation axis of the supporting member decreases with the driving operation.

[0014] Another typical structure disclosed in the present application is a cartridge and an electrophotographic image forming apparatus including such a drum unit or a drive transmission unit.

[0015] [Effects of the invention]

[0016] Existing technologies can be developed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The structures of the image forming apparatus main assembly and the process cartridge are shown.

[0018] Figure 2 It is a sectional view of the main assembly of the imaging device and the process cartridge.

[0019] Figure 3 is a sectional view of the process cartridge.

[0020] Figure 4 is an exploded perspective view of the process cartridge.

[0021] Figure 5 is an exploded perspective view of the process cartridge.

[0022] Figure 6 It is a sectional view of the main assembly of the imaging device and the process cartridge.

[0023] Figure 7 is a diagram of the main assembly of the imaging apparatus.

[0024] Figure 8 is an exploded perspective view of the drum unit.

[0025] Fig. 9 is a perspective view of a process cartridge.

[0026] Fig.10 It is a sectional view of the main assembly of the imaging device and the process cartridge.

[0027] Fig.11 is a diagram of a connection unit.

[0028] Fig.12 is a perspective view of the main assembly of the image forming apparatus.

[0029] Fig.13 is an exploded perspective view of the drum flange unit.

[0030] Fig.14 It is a sectional view of the main assembly of the imaging device and the process cartridge.

[0031] Fig.15 is a diagram of a connection unit.

[0032] Fig.16 It is a cross-sectional view of a drive transmission part and a non-drive transmission part. DETAILED DESCRIPTION

[0033] <Example 1>

[0034] Hereinafter, Embodiment 1 will be described in detail with reference to the drawings.

[0035] The direction of the rotation axis of the electrophotographic photosensitive drum is the longitudinal direction.

[0036] Further, in the longitudinal direction, the side of the electrophotographic photosensitive drum receiving the driving force from the main assembly of the image forming apparatus is a driving side, and the opposite side is a non-driving side.

[0037] refer to Figure 2 and Figure 3 , the overall structure and imaging processing will be described.

[0038] Figure 2 1 and 2 are sectional views of an apparatus main assembly (electrophotographic image forming apparatus main assembly, image forming apparatus main assembly) A and a process cartridge (hereinafter referred to as cartridge B) of an electrophotographic image forming apparatus according to Embodiment 1.

[0039] Figure 3 is a cross-sectional view of box B.

[0040] Here, the apparatus main assembly A is the portion of the electrophotographic image forming apparatus excluding the cartridge B.

[0041] <Overall Structure of Electrophotographic Image Forming Apparatus>

[0042] Figure 2 The electrophotographic image forming apparatus (image forming apparatus) shown is a laser printer using an electrophotographic system, in which a cartridge B can be installed in and removed from the apparatus main assembly A. An exposure device 3 (laser scanning unit) is provided for forming a latent image on an electrophotographic photosensitive drum 62 as an image bearing member of cartridge B when cartridge B is installed in the apparatus main assembly A. In addition, a sheet tray 4 is provided below cartridge B to accommodate a recording material (hereinafter referred to as a sheet PA) to be subjected to an image forming operation. The electrophotographic photosensitive drum 62 is a photosensitive member (electrophotographic photosensitive member) for forming an electrophotographic image thereon.

[0043] In addition, the main assembly A of the apparatus includes a pickup roller 5a, a feed roller pair 5b, a transfer guide 6, a transfer roller 7, a feed guide 8, a fixing device 9, a discharge roller pair 10, a discharge tray 11, etc., which are arranged along the feeding direction C of the sheet PA. The fixing device 9 includes a heating roller 9a and a pressure roller 9b.

[0044] <Imaging Processing>

[0045] Next, the image forming process will be briefly described. In response to a print start signal, an electrophotographic photosensitive drum (hereinafter referred to as photosensitive drum 62, or simply drum 62) is driven to rotate in the arrow R direction at a predetermined peripheral speed (process speed).

[0046] A charging roller (charging member) 66 to which a bias voltage is applied contacts the outer peripheral surface of the drum 62 , and uniformly charges the outer peripheral surface of the drum 62 .

[0047] The exposure device 3 outputs a laser beam L according to the image information. The laser beam L passes through a laser opening 61h provided in a cleaning frame 61 of the cartridge B, and scans and exposes the outer peripheral surface of the drum 62. Thus, an electrostatic latent image corresponding to the image information is formed on the outer peripheral surface of the drum 62.

[0048] On the other hand, Figure 3 As shown, in the developing unit 20 as the developing device, the toner T in the toner chamber 28 is stirred and fed by the rotation of the feeding member (stirring member) 30 and is sent out to the toner supply chamber 29 .

[0049] The toner T is carried on the surface of the developing roller 23 by the magnetic force of the magnetic roller 24 (fixed magnet). The developing roller 23 is a developer carrying member that carries the developer (toner T) on its surface so as to develop the latent image formed on the drum 62.

[0050] The toner T is frictionally charged by the developing blade 25 , and the layer thickness on the outer peripheral surface of the developing roller 23 as a developer carrying member is regulated by the developing blade.

[0051] The toner T is supplied to the drum 62 according to the electrostatic latent image to develop the latent image. In this way, the latent image is visualized as a toner image. The drum 62 is an image bearing member that carries the latent image or the image formed by the toner (toner image, developer image) on its surface. Figure 2 As shown, the sheet PA stored in the lower portion of the apparatus main assembly A is sent out from the sheet tray 4 by the pickup roller 5a and the feed roller pair 5b in a synchronous relationship with the output timing of the laser beam L. Then, the sheet PA is fed to a transfer position between the drum 62 and the transfer roller 7 via the transfer guide 6. At the transfer position, the toner image is sequentially transferred from the drum 62 to the sheet PA.

[0052] The sheet PA to which the toner image is transferred is separated from the drum 62 and fed to the fixing device 9 along the feed guide 8. Then, the sheet PA passes through the nip between the heating roller 9a and the pressure roller 9b constituting the fixing device 9. The pressurizing and heating fixing process is performed at the nip, and the toner image is fixed on the sheet PA. The sheet PA that has been subjected to the toner image fixing process is fed to the discharge roller pair 10, and is discharged to the discharge tray 11.

[0053] On the other hand, Figure 3 As shown, the drum 62 after image transfer is used again in an image forming process after the residual toner on the peripheral surface is removed by the cleaning member 65. The residual toner removed from the drum 62 is stored in a waste toner chamber 61b of the toner cleaning unit 60. The cleaning unit 60 is a unit including the photosensitive drum 62.

[0054] In the above description, the charging roller 66 , the developing roller 23 , the transfer roller 7 , and the cleaning member 65 are process means for acting on the drum 62 .

[0055] <Overall structure of the box>

[0056] Next, refer to Figure 3 , Figure 4 and Figure 5 , the overall structure of box B will be described. Figure 3 is a cross-sectional view of box B, and Figure 4 and Figure 5 1 is a perspective view showing the structure of the cartridge B. In this embodiment, screws for connecting the components will be omitted.

[0057] In addition, a description of an operating member unit including an operating lever member will be described hereinafter, and thus a description thereof is omitted here.

[0058] Box B includes a cleaning unit.

[0059] like Figure 3 As shown, the cleaning unit 60 includes a drum 62, a charging roller 66, a cleaning member 65, and a cleaning frame 61 supporting them. On the driving side of the drum 62, a driving side drum flange 71 provided on the driving side is rotatably supported by a hole portion 69a of a drum bearing 69. In a broad sense, the drum bearing 69 and the cleaning frame 61 may also be collectively referred to as a cleaning frame.

[0060] On the non-drive side, such as Figure 4 As shown, the hole 63a of the non-driving side drum flange 63 (see Figure 8 The portion (e)) is rotatably supported by a drum shaft 64 which is press-fitted into a hole 61c provided in the cleaning frame 61.

[0061] In the cleaning unit 60 , a charging roller 66 and a cleaning member 65 are respectively provided in contact with the outer peripheral surface of the drum 62 .

[0062] The cleaning member 65 includes: a rubber scraper 65a, which is a scraper-shaped elastic member made of rubber as an elastic material; and a supporting member 65b, which supports the rubber scraper. The rubber scraper 65a contacts the drum 62 in the reverse direction relative to the rotational movement direction of the drum 62. That is, the rubber scraper 65a contacts the drum 62 when the free end of the rubber scraper faces the upstream side of the rotational movement direction of the drum 62.

[0063] like Figure 3 As shown, waste toner removed from the surface of the drum 62 by the cleaning member 65 is stored in a waste toner chamber 61 b ​​formed by the cleaning frame 61 and the cleaning member 65 .

[0064] In addition, if Figure 3 As shown, a receiving plate 34 for preventing waste toner from leaking from the cleaning frame 61 is provided at an edge of the cleaning frame 61 in contact with the drum 62 .

[0065] The charging roller 66 is rotatably supported by the cleaning unit 60 via charging roller bearings (not shown) at both longitudinal end portions of the cleaning frame 61 .

[0066] The longitudinal direction of the cleaning frame 61 (longitudinal direction of the cartridge B) is parallel to the rotation axis (axial direction) of the drum 62. Therefore, hereinafter, when the longitudinal direction or axial direction is simply referred to, the axial direction of the drum 62 is referred to unless otherwise specified.

[0067] The charging roller 66 is pressed against the drum 62 by pressing the charging roller bearing toward the drum 62 with the charging roller urging member 68. The charging roller 66 is driven by the rotation of the drum 62.

[0068] like Figure 3As shown, the developing unit 20 includes a developing roller 23, a developing container 21 supporting the developing roller 23, a developing blade 25, etc. The developing roller 23 is rotatably supported by the developing container 21 through a driving side bearing member 26 and a non-driving side bearing member 27 provided at respective ends.

[0069] In addition, a magnetic roller 24 is provided in the developing roller 23. In the developing unit 20, a developing blade 25 is provided for restricting the toner layer on the developing roller 23. Figure 4 As shown, the developing roller 23 is provided with a spacer member 31 at both ends thereof, and a small gap is maintained between the developing roller 23 and the drum 62 by contacting the spacer member 31 and the drum 62. Figure 3 As shown, a spray prevention plate 33 for preventing toner from leaking from the developing unit 20 is provided at the edge of the bottom member 22 in contact with the developing roller 23. In addition, a feeding member 30 is provided in the toner chamber 28 formed by the developing container 21 and the bottom member 22. The feeding member 30 stirs the toner contained in the toner chamber 28 and feeds the toner to the toner supply chamber 29.

[0070] like Figure 4 and Figure 5 As shown, the cartridge B is constructed by combining the cleaning unit 60 and the developing unit 20.

[0071] First, the support boss 26a provided on the driving side bearing member 26 is fitted into the first hanging hole 61i on the driving side of the cleaning frame 61, and the support boss 27a provided on the non-driving side bearing member 27 is fitted into the second hanging hole 61j on the non-driving side. In this way, the developing unit 20 is rotatably (rotatably) connected to the cleaning unit 60. Thereafter, the cartridge B is formed by assembling the drum bearing 69 to the cleaning unit 60.

[0072] In this embodiment, the driving side urging member 32L and the non-driving side urging member 32R are composed of compression springs. The urging force of these springs pushes the developing unit 20 toward the cleaning unit 60, and the developing roller 23 is reliably pressed toward the drum 62. Similarly, the predetermined distance between the developing roller 23 and the drum 62 is maintained by the spacing members 31 installed at both ends of the developing roller 23.

[0073] <Box Installation Operation>

[0074] refer to Figure 1 Part (a), Figure 6 and Figure 7 , the operation of installing box B on the device main component A in this embodiment will be described. Figure 1Part (a) shows a sectional view of the state of the drive transmission member (drive shaft, drive output member) 1 and the drive side drum flange unit (drive transmission unit) 70 when the box B is mounted on the device main component A but is not driven. Figure 6 Part (a) is a sectional view of the state where box B is being installed on the main component A of the device. Figure 6 Part (b) is a sectional view showing the state in which box B has been installed on the main component A of the device. Figure 7 The state of the drive transmitting member 1 before the cartridge B is mounted to the apparatus main assembly A is shown.

[0075] like Figure 6 As shown in part (a) of FIG. 1 , in the process of installing cartridge B on the main assembly of the apparatus, the opening and closing door 13 of the main assembly of the apparatus A is opened by rotating around the rotation center (not shown). Next, cartridge B is inserted so that the guided portions 69d and 69e of cartridge B are guided along the guide rails 15d and 15e (only the driving side is shown). Then, as shown in FIG. Figure 6 As shown in part (b) of the drawing, the installation of box B is completed by bringing the positioned portions 69b and 69c provided on the drum bearing member 69 into proximity with or contact with the positioning portions 15b and 15c of the main assembly of the apparatus.

[0076] Two box pressing members 17 are rotatably mounted near the axial ends of the opening and closing door 13. Two box pressing springs 19 are mounted to the longitudinal ends of the main component A of the device. The box pressed portion 61e is provided at the longitudinal ends of the cleaning frame 61 to serve as a pushing force receiving portion of the box pressing spring 19. By completely closing the opening and closing door 13, a predetermined force is applied from the box pressing spring 19 to the box pressed portion 61e. In this way, the positioned portions 69b and 69c are maintained in contact with the positioning portions 15b and 15c of the main component of the device, and the box B is placed at a position where the imaging operation can be performed ( Figure 6 part (b)).

[0077] Here, the mounting / positioning structure and the pressing structure of the box B have been described with respect to the driving side, but the same structure can also be used on the non-driving side.

[0078] In this embodiment, if Figure 7 As shown, one end of the drive transmission member 1 is temporarily supported in the hole 15a of the drive side side plate 15. Before the cartridge B is installed, the drive transmission member tilts within the clearance (gap) range between the hole 15a and the drive transmission member 1 by its own weight. In addition, by the third urging member 76 (connector urging member, third elastic member, third spring) Fig. 9), the first coupling portion 72 is tilted substantially in the same direction as the drive transmission member 1 so as to engage with the drive transmission member 1. At this time, the rotation axis of the drive transmission member 1 and the rotation axis of the first coupling portion 72 form an angle, so that the axis of the drive transmission member 1 deviates from the axis of the drum 62 (see Figure 1 In this case, in order for the drum 62 to rotate stably during driving, the drum 62 must rotate in a state where the rotation axis of the drive transmission member 1 and the rotation axis of the drum 62 are coaxial with each other.

[0079] <Structure of Driving Side Drum Flange Unit and Engaging Operation of Coupling Member>

[0080] Next, the operation will be described in which, after the installation of box B is completed, the axis of the driving transfer member 1 is in an inclined state relative to the axis of the drum 62, and then the driving force acts, the driving transfer member 1 engages with the first connecting part 72, and the axis of the driving transfer member 1 becomes coaxial with the axis of the drum 62.

[0081] First reference Figure 8 , Fig. 9 and Fig.10 , the structure of the driving side drum flange unit (drive transmission unit) 70 will be described. Figure 8 Parts (a), (b) and (c) show a method of assembling the coupling unit 79. Figure 8 Part (d) shows a method of assembling the driving side drum flange unit 70. Figure 8 Part (e) shows a method of assembling the drum unit.

[0082] Fig. 9 2 is a perspective view showing the structure of the first coupling portion 72 and the third urging member (third elastic member, third spring) 76 . Fig.10 1 is a sectional view showing the state of the drive transmitting member 1 and the driving side drum flange unit 70 when the cartridge B is mounted on the apparatus main assembly A but is not driven.

[0083] Each assembly member that rotates together with the photosensitive drum 62 is called a drum unit. The drum unit includes the photosensitive drum 62, a drive side drum flange unit 70, and a non-drive side drum flange 63. The drive side drum flange unit 70 is fixed to one end of the photosensitive drum, and the non-drive side drum flange 63 is fixed to the other end (second end) of the photosensitive drum opposite to the above-mentioned one end.

[0084] The driving side drum flange unit 70 includes a driving side drum flange 71, a first connecting part 72, a second connecting part 73, a first pushing member 74 (a first elastic member, a first spring, an axial pushing member), a second pushing member 75 (a second elastic member, a second spring, a radial pushing member), a pin 78 and a cover member 77.

[0085] The first coupling portion 72 is provided with a driven transmission portion (driving force receiving portion) 72a, to which the driving force is transmitted from the driving transmission member 1 of the main component A of the device. The first coupling portion 72 transmits the driving force to the second coupling portion 73 by means of a pin 78 (second contact portion). The first coupling portion 72 and the pin 78 can be made integrally. The second coupling portion 73 includes a driven transmission portion 73a (second contacted portion) for receiving the driving force from the first coupling portion 72 and a driving transmission portion 73b (first contact portion) for transmitting the drive to the cover member 77. The cover member 77 is provided with a driven transmission portion 77a (first contacted portion) for receiving the driving force from the second coupling portion 73.

[0086] In the first connecting portion 72 and the second connecting portion 73, as shown in FIG. Figure 8 As shown in part (a) of the embodiment, the shaft portion 72k is inserted into the hole portion 73k, and the second coupling portion 73 is rotatably supported so as to be rotatable relative to the first coupling portion 72. Figure 8 As shown in part (b) of FIG. 1 , a second pushing member 75 for pushing in the rotational direction is provided between the first connecting portion 72 and the second connecting portion 73. In this embodiment, the second pushing member 75 includes a torsion coil spring, and both ends of the spring are in contact with the spring hooking portion 72h of the first connecting portion 72 and the spring hooking portion 73h of the second connecting portion 73, respectively, to restrict movement in the rotational direction. Figure 8 As shown in part (c) of FIG. 7 , a coupling unit (coupling member) 79 is formed by passing a pin 78 through the pin insertion holes 72 d and 73 d.

[0087] Then, if Figure 8 As shown in part (d) of FIG. 7 , after the coupling unit 79 is inserted into the driving side drum flange 71, a first pressing member 74 is provided for pressing the coupling unit 79 toward the driving side. Thereafter, the cover member 77 is fixed to the driving side drum flange 71 by means such as welding to form the driving side drum flange unit 70. Figure 8 As shown in part (e) of the drawing, the driving side drum flange unit 70 and the non-driving side drum flange 63 are inserted into the drum 62 and fixed by means such as press fitting or clamping.

[0088] The drum unit (62, 70, 63) assembled in this manner is rotatably supported by the frame (drum bearing 69) of the cartridge B. The drum unit (62, 70 and 73) can be mounted in the apparatus main assembly A as a part of the cartridge B.

[0089] The pin 78, the first connecting part 72 and the second connecting part 73 of the drum unit are collectively referred to as a connecting member. The connecting member (72, 73, 78) is connected to the drive transmission member (described below) of the main component A of the device to transmit the driving force (rotational force) from the main component A of the device to the drum 62. In the present embodiment, the connecting member is a unit that can be decomposed into a plurality of components (78, 72, 73), but the structure is not limited to this example, and the connecting member may also have an integral structure. For example, instead of connecting the first connecting part 72 and the second connecting part 73 with a pin 78, the first connecting part 72 and the second connecting part 73 may be a component. In the following, this structure will be described. In addition, the cover member 77 and the driving side drum flange 71 may be collectively referred to as a flange member, or the cover member 77 may be regarded as a part of the driving side drum flange 71.

[0090] The flange member (71, 77) is fixed to one end of the drum 62, and connects the drum 62 and the coupling member (72, 73, 78) for drive transmission. The flange member is an end member mounted to the end of the drum 62. The coupling member (72, 73 and 78) is supported by the flange member so that the coupling member (72, 73 and 78) is placed near the end of the photosensitive drum 62.

[0091] The flange member (71, 77) transmits the driving force from the coupling member (72, 73 and 78) to the drum 62. The flange member (71, 77) is a cartridge-side transmitting member (driving force transmitting member) that transmits the driving force.

[0092] The flange members (71, 77) are also connecting members that connect the coupling members (72, 73, 78) to the drum 62. The coupling members (72, 73 and 78) are indirectly connected to the drum 62 by means of the flange members (71, 77). As described above, the coupling members are connected to the drum 62 so that drive can be transmitted. In other words, the coupling members (72, 73 and 78) are operatively connected to the drum 62. That is, they are connected to each other so that as the coupling members (72, 73 and 78) rotate, the drum 62 is driven to rotate (operate).

[0093] The coupling members (72, 73 and 78) are tiltably supported by flange members (71, 77), which will be described in detail below. The flange members (71, 77) are also support members that support the coupling members.

[0094] In this embodiment, a convex shape having a substantially triangular cross section is adopted for the driven transmission portion (driving force receiving portion, driving input portion) 72a of the first coupling portion 72 (see Fig.16 Specifically, a shape is adopted in which a member having a substantially triangular cross section is twisted in a counterclockwise direction around the axis of the drum 62 from the driving side to the non-driving side.

[0095] like Fig. 9As shown, a chamfered portion 72e inclined in the longitudinal direction is provided on each triangular ridge line of the driving side end portion of the first coupling portion 72. Fig.10 As shown, the size of the chamfered portion 72e is set so that when the drive transmission member 1 is tilted in the V direction due to its own weight, a part of the chamfered portion 72e is located in the drive transmission portion 1a of the drive transmission member 1 in the radial direction. Fig.10 As shown, the minimum distance D1 from the drum center axis to the chamfered portion 72 e is selected to be smaller than the distance D2 from the drum center axis to the inlet of the drive transmission portion of the drive transmission member 1 .

[0096] In addition, the drive transmitting portion 73 b of the second coupling portion 73 and the driven transmitted portion (driving force receiving portion) 77 a of the cover member 77 are engaged with each other, and the cross section of the drive transmitting portion 73 b is substantially triangular.

[0097] In addition, if Fig.10 As shown, the first coupling portion 72 is brought closer to the longitudinal driving side (arrow G direction) by the first pushing member 74. In this way, the spherical restricted portion 72c of the first coupling portion 72 abuts against the tapered restricting portion 71c of the driving side drum flange 71. In this way, when the cartridge B is installed, a portion of the first coupling portion is reliably engaged in the interior of the drive transmission portion 1a in the longitudinal direction (see FIG. Figure 1 Here, the drive transmission portion 73b and the driven transmission portion 77a are centering portions having a centering function so as to align the rotation axis of the second coupling portion 73 with the rotation axis of the cover member 77 (drum 62). That is, when the second coupling portion 73 rotates relative to the cover member 77, the drive transmission portion 73b and the driven transmission portion 77a push the second coupling portion 73 in a direction tending to reduce the inclination angle of the second coupling portion 73 relative to the cover member 77.

[0098] Next, refer to Figure 1 and Fig.11 , the engaging operation of the first coupling portion 72 and the second coupling portion 73 will be described. Figure 1 The engaging operation of the drive transmitting member 1 , the first coupling portion 72 , and the second coupling portion 73 is shown. Fig.11 The relative positional relationship of the first coupling portion 72 with respect to the second coupling portion 73 is shown.

[0099] Figure 1 Part (a) shows a state in which the drive transmission portion 1a of the drive transmission member 1 and the driven transmission portion 72a of the first coupling portion 72 are out of phase with each other after the cartridge B is mounted on the apparatus main assembly A. From this point on, when the drive transmission member 1 rotates, the drive transmission member 1 is caused to rotate in a direction tending to reduce the inclination angle of the drive transmission member 1 which is in a tilted state in the direction of the arrow V due to its own weight by the chamfered portion 72e of the first coupling portion 72 ( Figure 1At the same time, the drive transmission member 1 is pulled toward the non-driving side (arrow N direction) due to the twisted shape, and as shown in FIG. Figure 1 As shown in part (b), the surface 1f of the drive transfer member 1 is brought into contact with the end face 72f of the first connecting part 72. Here, the surface 1f of the drive transfer member 1 and the end face 72f of the first connecting part 72 are perpendicular to the rotation axis of the drive transfer member 1 and the rotation axis of the first connecting part 72. At this time, the driven transfer part 72a of the first connecting part 72 and the driving transfer part 1a of the drive transfer member 1 are configured to ensure the longitudinal engagement amount required for stable drive transmission. In addition, the centers of the triangles are aligned when the phases of the triangles are consistent, and the rotation axis of the drive transfer member 1 and the rotation axis of the first connecting part 72 are aligned with each other by abutting between surfaces perpendicular to them. In this way, the engagement operation between the drive transfer member 1 and the first connecting part 72 is completed.

[0100] In the present embodiment, the tilting direction of the drive transmission member 1 is the gravity direction, but the tilting direction is not limited to the gravity direction; as long as the above-mentioned condition that a part of the chamfered portion 72e is located inside the drive transmission portion 1a is satisfied, engagement can be achieved regardless of the tilting direction. In addition, even when the rotation axis of the first coupling portion 72 and the rotation axis of the drive transmission member 1 are neither parallel nor coaxial, the first coupling portion 72 can be engaged with the drive transmission member 1 as long as the above-mentioned condition is satisfied.

[0101] As described above, the drive transmission member 1 and the first coupling portion 72 become engaged, and drive transmission from the device main assembly A to the cartridge B is enabled. At this time, the drive transmission member 1 and the first coupling portion 72 are coaxial with each other, but they are still in an inclined state relative to the drum 62. Next, a structure for making the drive transmission member 1 and the first coupling portion coaxial with the drum rotation axis in a state where the rotation axis of the drive transmission member 1 and the rotation axis of the first coupling portion are inclined relative to the drum rotation axis will be described.

[0102] Inside the driving side drum flange 71, a second coupling portion 73 is provided which is coaxially and rotatably supported relative to the first coupling portion 72. Between the first coupling portion 72 and the second coupling portion 73, there is a rotational direction freedom of more than 120° due to the pin insertion hole 73d. Before the start of rotation, the first coupling portion 72 is in the first position relative to the second coupling portion 73 (see FIG. 1 ) by the second urging member 75 pushing in the direction opposite to the rotational direction (arrow F direction) which is the direction during driving. Fig.11 Then, when the first coupling portion 72 is rotated by more than 120°, it moves to the second position (see Fig.11Part (b)), at the second position, the pin 78 abuts against the non-drive transmission part 73a. Here, for the second coupling part 73, the pin 78 abuts against the non-drive transmission part 73a. Since the second coupling part 73 receives the driving force from the first coupling part 72, the second coupling part 73 does not rotate until the first coupling part 72 moves from the first position to the second position.

[0103] Then, when the second coupling portion 73 is in the second position (see Fig.11 The pin 78 abuts against the driven transmission portion 73a, so that the driving force of the first coupling portion 72 is transmitted, and the second coupling portion 73 becomes rotatable. When the second coupling portion 73 further rotates, as shown in FIG. Figure 1 As shown in part (c), the driving transmission part 73b of the second coupling part 73 is engaged with the driven transmission part 77a of the cover member 77, and the cover member 77 becomes rotatable. At this time, the triangular phase of the driving transmission part 73b and the triangular phase of the driven transmission part 77a are aligned, and the second coupling part 73 is pulled toward the non-driving side (in the direction of arrow N) due to the twisted shape, and the end face 73f is brought into contact with the surface 77f of the cover member 77. Here, the end face 73f of the second coupling part 73 and the surface 77f of the cover member 77 are perpendicular to the rotation axis of the second coupling part 73 and the rotation axis of the cover member 77. When the phases of the triangles are consistent, the centers of the triangles are consistent; and by abutting each other with the faces perpendicular to the above-mentioned rotation axis, the rotation axes become parallel to each other. Therefore, the rotation axis of the second coupling part 73 and the rotation axis of the cover member 77 are aligned with each other. Since the cover member is fixed to the driving side drum flange 71 and the driving side drum flange 71 is fixed to the drum 62, the rotation axis of the second coupling part 73 is coaxial with the drum 62.

[0104] Here, the rotation axis of the drive transmission member 1 and the rotation axis of the first coupling portion 72 and the rotation axis of the second coupling portion 73 and the rotation axis of the drum 62 are aligned with each other. Since the first coupling portion 72 and the second coupling portion 73 are coaxial, the drive transmission member 1 and the drum 62 can rotate with their rotation axes aligned with each other.

[0105] As described above, in this embodiment, the first coupling portion 72 can engage with the drive transmission member 1 whose axis is inclined relative to the axis of the drum 62, and can make them coaxial with the drum 62. With this structure, the drive transmission accuracy from the main assembly A to the box B can be improved.

[0106] In the present embodiment, the coupling member is provided with the first coupling portion 72 and the second coupling portion 73 which are relatively movable to each other. This provides the following advantages.

[0107] At the stage when the drive transmission member 1 starts to rotate, the first coupling part of the coupling member may not be engaged with the drive transmission member 1. Even in this case, friction will be generated between the first coupling part 72 and the drive transmission member 1, so the friction may cause the first coupling part 72 to rotate slightly before engaging with the drive transmission member 1. If the rotation is transmitted from the first coupling part 72 to the second coupling part 73 when the first coupling part 72 is not engaged with the drive transmission member 1, the above-mentioned centering action will occur unintentionally between the second coupling part 73 and the flange member (cover member 77). That is, as the second coupling part 73 engages with the cover member 77 of the flange member, the inclination angle of the second coupling part 73 relative to the drum 62 becomes smaller. Through this action, the inclination angle of the first coupling part 72 relative to the drum 62 also becomes smaller. If the inclination angle of the first coupling part 72 decreases before engaging with the drive transmission member 1, the first coupling part 72 moves away from the drive transmission member 1, with the result that the first coupling part 72 cannot engage with the drive transmission member 1.

[0108] Therefore, in the present embodiment, the first coupling portion 72 can be made to rotate within a certain range relative to the second coupling portion 73. Therefore, even if the first coupling portion 72 is slightly rotated unintentionally before being engaged with the drive transmission member 1, the rotation is not transmitted to the second coupling portion 73. Only after the drive transmission member 1 and the first coupling portion 72 are firmly engaged with each other, the rotation can be transmitted from the first coupling portion to the second coupling portion 73. Therefore, the centering action does not occur unintentionally before the first coupling portion 72 and the drive transmission member 1 are engaged with each other.

[0109] In particular, in the present embodiment, as described above, the angle (phase difference) at which the first coupling portion 72 can rotate relative to the second coupling portion 73 from the first position to the second position is set to 120 degrees or more.

[0110] The 120 degree angle is the angle θ (= 120°) between the straight lines connecting the vertices from the center of an equilateral triangle (see Fig.16 ). Even if the drive transmission member 1 and the first coupling portion 72 have different triangular phases when the cartridge is mounted on the main assembly of the device, the phase difference is less than 120 degrees. That is, generally, if the drive transmission member 1 rotates a maximum of 120 degrees, the triangular shape of the drive transmission member 1 and the triangular shape of the first coupling portion 72 can engage with each other. Even if the first coupling portion 72 is slightly rotated due to the above-mentioned frictional force before engagement, the rotation angle is therefore less than 120 degrees, and such rotation of the first coupling portion 72 does not cause the first coupling portion 72 to start rotating the second coupling portion 73.

[0111] Therefore, after the first coupling portion 72 is reliably engaged with the drive transmission member 1 and rotates, the rotation of the second coupling portion 73 starts, and then the drum 62 can rotate.

[0112] The alignment force generated between the second coupling portion 72 and the flange member (77) before the first coupling portion 72 and the drive transmission member 1 are engaged with each other can be suppressed to correct the inclination of the first coupling portion 72. Therefore, the occurrence of poor engagement between the drive transmission member 1 and the first coupling portion 72 can be suppressed.

[0113] However, the coupling member of the coupling unit 79 does not necessarily have to be divided into the first coupling portion 72 and the second coupling portion 73 as described above. For example, in a case where the first coupling portion 72 hardly rotates before engaging with the drive transmission member 1 (for example, the friction force generated between the first coupling portion 72 and the drive transmission member 1 is sufficiently small), the above structure is unnecessary. In this case, the coupling portion does not have to be divided into the first coupling portion 72 and the second coupling portion 73, and they can be integral. In addition, even if the coupling member is divided into the first coupling portion 72 and the second coupling portion 73, the rotatable angle of the first coupling portion 72 relative to the second coupling portion 73 may be less than 120 degrees.

[0114] As described above, in order to achieve the engagement between the drive transmission portion 1a of the drive transmission member 1 and the driven transmission portion 72a of the first coupling portion 72 and the engagement between the drive transmission portion 73b of the second coupling portion 73 and the driven transmission portion 77a of the cover member 77, they have corresponding characteristic shapes. In the present embodiment, the shape adopted is a triangle having an equilateral triangle cross section in a plane perpendicular to the rotation axis and having an arc-shaped chamfered vertex (see Fig.16 ). In order to obtain the same effect as in this embodiment, the shape is not necessarily limited to this shape.

[0115] <Cartridge disassembly operation>

[0116] Next, the operation of separating the drive transmitting member 1 and the first coupling 72 in the engaged state from each other and taking out the cartridge B from the apparatus main assembly A will be described.

[0117] When the box B is pulled out to the outside, the connecting member 2 ( Fig.12 ) rotates, so that the connecting member 2 moves toward the driving side (arrow G direction) along the inclined portion (not shown) provided on the driving side plate 15. Accompanying this, the drive transmission member 1 moves toward the driving side. In this way, the drive transmission member 1 moves while rotating in the reverse direction due to the triangular twisted shape, and the engagement with the first coupling portion is released. When the engagement is released, the drive transmission member 1 and the first coupling portion 72 become inclined again.

[0118] The structure of the present embodiment described so far can be briefly summarized as follows. The drum unit of the present embodiment has a coupling member (79) capable of receiving a driving force (rotational force) by engaging and connecting with the drive transmission member 1 (see Figure 8 ). The coupling member 79 is tiltably supported by the flange member (71, 77) fixed to the photosensitive drum 1. That is, the angle formed by the rotation axis of the coupling member 79 and the rotation axis of the photosensitive drum 62 can be changed.

[0119] The drive transmission member 1 is tilted inside the main assembly A of the apparatus (see Figure 4 The coupling member 79 is also tiltable relative to the photosensitive drum 62 so that the coupling member can engage with the drive transmission member 1 ( Figure 4 ). Specifically, in the present embodiment, the cartridge B is provided with a pressing member (elastic member, spring) 76 for tilting the coupling member 79 in a predetermined direction so that it can engage with the drive transmission member 1 (see Fig. 9 ). When the coupling member 79 is tilted, the coupling member 79 rotates by receiving the driving force from the drive transmission member 1 (see Figure 1 When the coupling member 79 rotates relative to the flange member (71, 79), the centering portion (drive transmission portion 73b, driven transmission portion 77a, see Figure 8 ) applies force to the coupling member 79 to reduce its inclination angle. In this way, the inclination angle between the coupling member 79 and the drive transfer member 1 connected to the coupling member 79 becomes smaller. Therefore, the driving force can be stably transmitted from the drive transfer member 1 to the photosensitive drum 62 with the help of the coupling member (72, 73) and the flange member (71, 77). In the present embodiment, the drive transfer member 1, the coupling member (72, 73) and the photosensitive drum 62 are arranged roughly coaxially during drive transmission, but they are not necessarily coaxial. That is, as long as the inclination angle between the drive transfer member 1 and the coupling member (72, 73) becomes smaller, the effect of improving the drive transmission accuracy is provided.

[0120] As described above, the drive transmission member 1 can be tilted or tilted inside the main body of the electrophotographic image forming apparatus, depending on the support structure for supporting the drive transmission member 1. From the perspective of engaging and connecting the coupling member (72, 73) with the drive transmission member 1 to achieve drive transmission, the drive transmission structure including the coupling member described in this embodiment is suitable.

[0121] In addition, a support structure in which the drive transmission member is intentionally tilted so that the drive transmission member 1 does not interfere with the mounting / removal operation when the drum unit or cartridge is mounted or removed can also be considered. The drive transmission structure of the present embodiment is also applicable to such a support structure.

[0122] In addition, the drive side drum flange unit (drive transmission unit) 70 of the present embodiment is integrated with the photosensitive drum to form a drum unit. That is, the drive transmission unit 70 can be mounted on and removed from the main assembly of the imaging device as a component of the drum unit or a component of the box including the drum unit. However, the drive transmission unit 70 does not necessarily have to be integrated with the photosensitive drum, and the drive transmission unit 70 does not necessarily have to be a component of the drum unit or a component of the box.

[0123] That is, the drive transmission unit 70 may be a unit (a detachably mounted unit, an accessory) or a component thereof that can be installed by a user on the main component of the electronic photographic imaging device. That is, the drive transmission unit 70 may be a unit that can receive a driving force by connecting to the drive transmission member 1 when it is installed on the main component of the electronic photographic imaging device. The object to which the drive transmission unit 70 transmits the driving force may not be the photosensitive drum 62, but other components, such as the developing roller 23. In addition, the drive transmission unit 70 does not have to be directly connected to the object that receives the driving force (the photosensitive drum in this embodiment). For example, it is conceivable that the box has a drive transmission unit 70 and a photosensitive drum 62, and the two are arranged at positions separated from each other and are indirectly connected to each other by means of gears, etc. In this case, the connecting member of the drive transmission unit 70 can also be operably connected to the photosensitive drum 62, that is, in a manner that can perform drive transmission.

[0124] Alternatively, the drive transmission unit 70 can be separated from the drum unit or the box. In this case, preferably, the user first installs the drive transmission unit 70 on the imaging device main assembly, and then the user installs the box or the drum unit on the imaging device main assembly and connects them to the drive transmission unit 70.

[0125] In the present embodiment, one of the driving transmission part 73b and the driven transmission part 77a as the centering part has a convex shape (protrusion, convex part), and the other has a concave shape (depression, concave part) that can engage with the protrusion. By rotating the driving transmission part 73b relative to the driven transmission part 77a, one of the convex shape and the concave shape engages with the other while rotating. Since at least one of the convex shape and the concave shape is twisted, when one of the convex shape and the concave shape engages with the other while rotating, the axis of the convex shape and the axis of the concave shape are aligned by the twisting action. Therefore, the inclination angle of the flange member (71, 77) relative to the coupling member 79 becomes smaller, and the inclination angle of the coupling member 79 relative to the drum 62 also becomes smaller. In this way, the rotation axis of the coupling member 79 and the rotation axis of the drum 62 are roughly aligned with each other. In the present embodiment, the driving transmission part 73b has a convex shape, and the driven transmission part 77a has a concave shape. In addition, both the convex shape and the concave shape are twisted.

[0126] The cross-sectional shape of the drive transmission portion 73b and the cross-sectional shape of the driven transmission portion 77a are substantially triangular. That is, the cross-sectional shape is an arc shape near the vertex of an equilateral triangle. However, the cross-sectional shape may have other different shapes.

[0127] <Example 2>

[0128] Next, Example 2 will be described. In this embodiment, the drive transmission member 1 is also constructed to be tiltable (inclined). In Example 2, the installation / removal operation of the box B and the engagement between the drive transmission member 1 and the first connecting portion 82 are the same as those in Example 1, so their description will be omitted. Example 2 is a modified form of the structure of the drive side drum flange unit 80 for changing the state in which the rotation axis of the first connecting portion 82 and the rotation axis of the drum 62 are deviated to a state in which they are coaxial with each other. Therefore, in the following reference Fig.13 , Fig.14 and Fig.15 In the description of FIG. 1 , a structure in which the drive transmission member 1 and the first coupling portion 82 are made coaxial with the rotation axis of the drum 62 after being engaged with each other will be described. Fig.13 A method of assembling the coupling unit 89 and the driving side drum flange unit 80 is shown.

[0129] Fig.14 An engaging operation between the drive transmitting member 1 , the first coupling portion 82 , and the second coupling portion 83 is shown. Fig.15 The relative positional relationship of the first coupling portion with respect to the second coupling portion 83 is shown.

[0130] like Fig.13 As shown in part (a) of FIG. 8 , the coupling unit 89 includes a first coupling portion 82, a second coupling portion 83, a second pressing member 85, and a pin 88. Fig.13 As shown in part (b) of the drawing, the driving side drum flange unit 80 includes a driving side drum flange 81 , a coupling unit 89 , a first urging member 84 and a cover member 87 .

[0131] The drum unit in this embodiment corresponds to the drum unit in Embodiment 1, wherein the drive side drum flange unit 70 (see Figure 8 The drum unit in this embodiment includes the driving side drum flange unit 80, the photosensitive drum 62 and the driven side drum flange 63 (see FIG. Figure 8 part (e)).

[0132] In addition, the driving side drum flange 81 and the cover member 87 may be collectively referred to as flange members, or the cover member 87 may be regarded as a component of the driving side drum flange 81. The first connecting portion 82 includes a driven transmission portion 82a engaged with the driving transmission member 1 to receive the driving force, and includes a shaft portion 82k, and is tilted by a third pushing member 86 (not shown). The second connecting portion 83 includes: a hole portion 83k, into which the shaft portion 82k is inserted and the hole portion is coaxially and rotatably supported by the first connecting portion 82; and a driving transmission portion 83b, which is engaged with the driven transmission portion 81a of the driving side drum flange 81 to transmit the driving force. The first pushing member (first elastic member, first spring) 84 pushes the first connecting portion 82 and the second connecting portion 83 toward the longitudinal driving side ( Fig.14 Similar to Embodiment 1, the second urging member 85 urges the first coupling portion 82 in the rotational direction relative to the second coupling portion 83.

[0133] In addition, the first coupling portion 82 and the second coupling portion 83 are provided with inclined portions 82g and 83g that contact each other, and their movement in the longitudinal direction is achieved by the rotation of the first coupling portion 82. When the first coupling portion 82 does not receive a driving force, the first coupling portion is urged in the rotation direction by the second urging member 85, and the pin 88 is inserted into the pin insertion hole 83d of the second coupling portion 83 to reach the first position in contact with its end surface (see Fig.15 As in the first embodiment, the pin insertion hole 83d of the second coupling portion 83 has a rotational freedom of more than 120°. Therefore, when the first coupling portion 82 rotates more than 120°, the pin 88 reaches the second position where it abuts against the driven transmission portion 83a (see Fig.15 Then, the driving force of the first coupling portion 82 is transmitted, and the second coupling portion 83 becomes rotatable. At the same time, at the second position, the second coupling portion 83 moves toward the non-driving side (arrow N direction) along the inclined portions 82g and 83g, and the restricted portion 83c (second restricted portion) having a spherical shape contacts the conical restricting portion 87c (second restricting portion) of the cover member 87.

[0134] The second coupling portion 83 is provided with a drive transmission portion 83b, the driving side drum flange 81 is provided with a driven transmission portion 81a corresponding to the drive transmission portion 83b, and the second coupling portion 83 is movable in the longitudinal direction relative to the driving side drum flange 81. When the second coupling portion 83 rotates, the driving side drum flange 81 and the drum become rotatable.

[0135] The first coupling portion 82, the second coupling portion 83 and the pin 88 are collectively referred to as coupling members. The coupling members (82, 83 and 88) are configured to transmit the driving force (rotational force) to the photosensitive drum 62 via the flange members (81, 87).

[0136] Next, the engaging operation between the first coupling portion 82 and the second coupling portion 83 will be described.

[0137] like Fig.14 As shown in part (a) of FIG. 1 , after the installation of the cartridge B is completed, the drive transmission member is tilted and does not engage with the first coupling portion 82. At this time, in the first coupling portion 82, the spherical restricted portion 82c (first restricted portion) is brought into contact with the conical restricting portion 81c (first restricting portion) of the drive side drum flange 81 by the first pressing member 84. Then, as shown in FIG. Fig.14 As shown in part (b), when the driving transmission member 1 rotates, the triangular phase of the driving transmission part 1a and the triangular phase of the driven transmission part 82a are consistent with each other, and the surface 1f of the driving transmission member 1 abuts against the end face 82f of the first connecting part 82, so that rotation is achieved, as in Example 1. Therefore, the first connecting part 82 rotates in a state in which the rotation axis of the driving transmission member 1 is aligned with the rotation axis of the first connecting part 82. Then, the inclined portion 83g of the second connecting part 83 moves along the inclined portion 82g toward the longitudinal non-driving side (in the direction of arrow N). At this time, when moving along the inclined portion 82g, due to the hole portion 83d, there is a rotational direction freedom of more than 120° between the first connecting part 82 and the second connecting part 83, and therefore the connecting part 83 does not rotate. When rotated to a predetermined angle of more than 120°, as shown Fig.14 As shown in part (c) of FIG. 1 , the second coupling portion 83 moves along the inclined portion 82g to the second position on the non-driving side (see FIG. 1 ). Fig.15 (b)), the spherical restricted portion 83c abuts against the conical restricting portion 87c of the cover member 87. At the same time, the second coupling portion 83 rotates, and the drive transmitting portion 83b of the second coupling portion 83 contacts the driven transmitting portion 81a of the driving side drum flange 81 to rotate the drum 62.

[0138] Here, the first coupling portion 82 abuts against the restricting portion 81c of the driving side drum flange 81, and the second coupling portion 83 abuts against the restricting portion 87c of the cover member 87. Fig.14 As shown in part (c) of the drawing, the positions of the centers Q1 and Q2 of the restricted portion 82c of the first coupling portion 82 and the restricted portion 83c of the second coupling portion 83 are determined. Here, the center axis of the tapered shape of the restricting portion 81c of the driving side drum flange 81 and the center axis of the tapered shape of the restricting portion 87c of the cover member 87 are both set to be coaxial with the rotation axis of the drum 62. In addition, the centers Q1 and Q2 are set to be on the rotation axis of the first coupling portion 82 and the rotation axis of the second coupling portion 83, respectively. Therefore, since the first coupling portion 82 and the second coupling portion 83 are coaxial with each other, the straight line connecting the centers Q1 and Q2, i.e., the rotation axis of the first coupling portion 82 and the second coupling portion 83, is coaxial with the rotation axis of the drum 62.

[0139] As described above, the drive transmission member 1 , the first coupling 82 , the second coupling 83 , the cover member 88 , the driving side drum flange 81 , and the drum 62 are rotated in a state where all of their rotational axes are aligned.

[0140] Similar to Embodiment 1, the first coupling portion 82 in this embodiment can be engaged with the drive transmission member 1 configured such that the rotation axis is inclined relative to the axis of the first coupling portion 82 before engagement. In addition, even in the case where the rotation axis of the first coupling portion 82 and the rotation axis of the drive transmission member 1 are parallel and not coaxial before engagement, the first coupling portion 82 in this embodiment can be engaged with the drive transmission member 1.

[0141] In the present embodiment, the limiting portion 81c of the driving side drum flange 81 and the restricted portion 82c of the first coupling portion 82 respectively adopt a concave shape having a tapered surface and a convex shape having a spherical surface. Similarly, the limiting portion 87c of the cover member 87 and the restricted portion 83c of the second coupling portion 83 respectively adopt a concave shape including a tapered surface and a convex shape including a spherical surface. In order to provide the same effect as in the present embodiment, the relationship between the concave shape having a tapered surface and the convex shape having a spherical surface may be reversed.

[0142] The restricting portions 81 c and 87 c and the restricted portions 82 c and 83 c are centering portions in the second embodiment.

[0143] As described above, also in Embodiment 2, similarly to Embodiment 1, the first coupling portion 82 is engaged with the drive transmission member 1 whose axis is inclined relative to the axis of the drum 62, and a coaxial state with the drum 62 can be established. With this structure, the drive transmission accuracy from the main component A of the device to the box B can be improved.

[0144] The following is an overview of the present embodiment described so far.

[0145] Regarding the coupling member of the present embodiment, the first coupling portion 82 and the second coupling portion 83 are configured to be movable relative to each other. Fig.14 As shown in part (b) of the embodiment, the first coupling portion 82 rotates by engaging with the drive transmission member 1. Then, one of the first coupling portion 82 and the second coupling member 83 moves in the axial direction relative to the other. That is, the second coupling portion 83 moves in the drum axial direction ( Fig.14 moves in the direction of arrow N in part (c).

[0146] Therefore, the restricted portion 82c provided on the first connecting portion 82 contacts (presses) the restricting portion 81c provided on the flange member (drive side drum flange 81). In addition, the restricted portion 83c provided in the second connecting portion 83 contacts (presses) the restricting portion 87c provided in the flange member (cover member 77). Through these contact actions, the connecting members (first connecting portion 82, second connecting portion 83) are centered. That is, the inclination angle of the connecting members (82, 83) relative to the photosensitive drum 62 becomes smaller. Therefore, as Fig.14 As shown in part (c) of the drawing, the drive transmission member 1, the coupling member (82, 83) and the photosensitive drum 62 are arranged substantially coaxially, and the accuracy of the drive transmission is improved.

[0147] The first coupling portion 82 and the second coupling portion 83 each have inclined portions 82g and 83g as a cam mechanism (see Fig.13 Therefore, the structure is such that when the first coupling portion 82 rotates relative to the second coupling portion 83, the relative position between the first coupling portion 82 and the second coupling portion 83 changes in the axial direction along the inclined portions 82g and 83g.

[0148] In addition, one of the restricted portion 82c provided on the first coupling portion 82 and the restricting portion 81c provided on the flange member (driving side drum flange 81) has a spherical convex shape, and the other has a spherical or conical concave shape. In addition, one of the restricted portion 83c provided on the second coupling portion 83 and the restricting portion 87c provided on the flange member (closing member 77) has a spherical convex shape, and the other has a spherical or conical concave shape.

[0149] The centering action is provided by the engagement between the concave and convex shapes as described above.

[0150] [Industrial Applicability]

[0151] According to the present invention, there are provided a drum unit, a drive transmission unit, a cartridge usable for an image forming apparatus such as an electrophotographic image forming apparatus, and an electrophotographic image forming apparatus suitable therefor.

[0152] The present invention is not limited to the above embodiments, and various changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, the following claims are attached to disclose the scope of the present invention.

[0153] This application claims priority from Japanese Patent Application No. 2019-109671, filed on Jun. 12, 2019, and the entire contents of which are incorporated herein by reference.

Claims

1. A drum unit that can be used in a cartridge, the drum unit comprising: Photosensitive drum; as well as a coupling member disposed adjacent to an end of the photosensitive drum and connected to the photosensitive drum so as to be able to transmit a driving force to the photosensitive drum by rotating about a coupling member rotation axis, The coupling member is tiltable relative to the rotation axis of the photosensitive drum, and the tilt angle relative to the rotation axis of the photosensitive drum decreases as the coupling member rotates relative to the photosensitive drum around the rotation axis of the coupling member.

2. The drum unit according to claim 1, further comprising a flange member mounted to an end portion of the photosensitive drum, wherein The coupling member is tiltably supported by the flange member.

3. The drum unit according to claim 2, wherein: One of the coupling member and the flange member includes a convex portion, and the other of the coupling member and the flange member includes a concave portion; When the coupling member is rotated relative to the flange member, the inclination angle of the coupling member is reduced by engagement between the convex portion and the concave portion.

4. The drum unit according to claim 3, wherein: At least one of the convex portion and the concave portion is twisted.

5. The drum unit according to claim 3, wherein The male portion has a generally triangular cross-section taken along a plane perpendicular to the axis of rotation of the coupling member.

6. The drum unit according to claim 3, wherein The coupling member includes a first coupling portion and a second coupling portion capable of transmitting a driving force from the first coupling portion to the photosensitive drum; the first coupling portion is rotatable relative to the second coupling portion within a predetermined angular range, and the second coupling portion includes one of a convex portion and a concave portion. 7 . The drum unit according to claim 6 , further comprising an urging member for urging the first coupling portion to rotate the first coupling portion relative to the second coupling portion.

8. The drum unit according to claim 6, wherein The first coupling portion is rotatable relative to the second coupling portion by an angle not less than 120°.

9. The drum unit according to claim 1 or 2, further comprising an urging member for urging the coupling member in a direction of a rotation axis of the photosensitive drum.

10. A box comprising: A drum unit as claimed in any one of claims 1 to 10; as well as The frame is used to rotatably support the drum unit.

11. A cartridge according to claim 10, further comprising an urging member for urging the coupling member to incline the coupling member with respect to a rotation axis of the photosensitive drum.

12. A drive transmission unit, which can be mounted on a main assembly of an electrophotographic imaging device, the drive transmission unit comprising: Supporting members; and a coupling member supported by the support member so as to be capable of transmitting a driving force to the support member by rotating about a coupling member rotation axis, The connecting member is tiltable relative to the rotation axis of the supporting member, and the tilt angle relative to the rotation axis of the supporting member decreases as the connecting member rotates relative to the supporting member around the rotation axis of the connecting member.

13. The drive transmission unit according to claim 12, wherein: One of the coupling member and the support member includes a convex portion and the other includes a concave portion; When the coupling member rotates relative to the supporting member, the inclination angle of the coupling member is reduced by engagement between the convex portion and the concave portion.

14. The drive transmission unit according to claim 13, wherein: At least one of the convex portion and the concave portion is twisted.

15. The drive transmission unit according to claim 13, wherein: The male portion has a generally triangular cross-section taken along a plane perpendicular to the axis of rotation.

16. The drive transmission unit according to claim 12 or 13, wherein: The coupling member includes a first coupling portion and a second coupling portion capable of transmitting a driving force from the first coupling portion to the supporting member; the first coupling portion is rotatable relative to the second coupling portion within a predetermined angular range, and the second coupling portion includes one of a convex portion and a concave portion. 17 . The drive transmission unit according to claim 16 , further comprising an urging member for urging the first coupling portion to rotate the first coupling portion relative to the second coupling portion.

18. The drive transmission unit according to claim 16, wherein: The first coupling portion is rotatable relative to the second coupling portion by an angle not less than 120°.

19. The drive transmission unit according to claim 12 or 13, further comprising an urging member for urging the coupling member in a direction of a rotation axis of the photosensitive drum.

20. A box comprising: A drive transmission unit as claimed in any one of claims 12 to 19; as well as The photosensitive drum is capable of receiving driving force from the drive transmission unit.

21. The cartridge according to claim 20, further comprising an urging member for urging the coupling member to incline the coupling member with respect to the supporting member rotation axis.

22. An electrophotographic imaging device comprising: The box according to claim 10 or 20; as well as A main assembly to which the cartridge is removably mountable, the main assembly comprising a tiltable drive output member connectable to a coupling member of the cartridge.

23. An electrophotographic imaging device comprising: A drive transmission unit as claimed in any one of claims 12 to 19; as well as A main assembly to which a drive transfer unit is detachably mountable, the main assembly comprising a tiltable drive output member connectable to a coupling member of the drive transfer unit.

24. A drum unit for a cartridge, the drum unit comprising: a photosensitive drum having a rotation axis; A flange is coaxially arranged at the end of the photosensitive drum, and includes a joint portion; a coupling member supported by the flange so that the coupling member is tiltable relative to the flange and the photosensitive drum, the coupling member including an engaging portion engageable with an engaging portion of the flange, the coupling member having a rotation axis; The coupling member is configured such that: (i) as the coupling member rotates relative to the flange about the coupling member rotation axis, the engaging portion of the coupling member engages with the engaging portion of the flange; (ii) as the engaging portion of the coupling member engages with the engaging portion of the flange, the inclination angle of the coupling member relative to the photosensitive drum rotation axis decreases; The connecting member is configured to transmit driving force to the photosensitive drum through a connecting portion of the connecting member and a connecting portion of the flange.

25. The drum unit according to claim 24, wherein One of the engaging portion of the coupling and the engaging portion of the flange includes a convex portion, and the other of the engaging portion of the coupling and the engaging portion of the flange includes a concave portion.

26. The drum unit according to claim 25, wherein At least one of the convex portion and the concave portion is twisted.

27. The drum unit according to claim 26, wherein The male portion has a generally triangular cross-section taken along a plane perpendicular to the male portion's axis of rotation.

28. The drum unit according to claim 24, wherein The coupling comprises: (i) a first coupling portion; and (ii) a second coupling portion configured to receive a driving force from the first coupling portion, the second coupling portion comprising an engagement portion of the coupling; Therein, the first coupling part can be partially rotated about the coupling member rotation axis relative to the second coupling part.

29. The drum unit according to claim 28, further comprising an urging member configured to urge the first coupling portion to rotate the first coupling portion relative to the second coupling portion.

30. A drum unit according to claim 28 or 29, wherein The first coupling portion is rotatable relative to the second coupling portion by an angle not less than 120°.

31. A box comprising: Photosensitive drum; A frame for rotatably supporting the photosensitive drum; a supporting member operatively connected to the photosensitive drum so that a driving force can be transmitted from the supporting member to the photosensitive drum, the supporting member including an engaging portion, the supporting member having a rotation axis; and a coupling piece supported by the support member so that the coupling piece is tiltable relative to the support member, the coupling piece including an engagement portion engageable with an engagement portion of the support member, the coupling piece having a rotation axis; The coupling member is configured such that: (i) as the coupling member rotates relative to the support member about the coupling member rotation axis, the engaging portion of the coupling member engages with the engaging portion of the support member; (ii) as the engaging portion of the coupling member engages with the engaging portion of the support member, the inclination angle of the coupling member relative to the support member rotation axis decreases; The connecting member is configured to transmit the driving force to the supporting member through the engaging portion of the connecting member and the engaging portion of the supporting member.

32. The cartridge of claim 31, wherein One of the engaging portion of the coupling and the engaging portion of the support member includes a convex portion, and the other of the engaging portion of the coupling and the engaging portion of the support member includes a concave portion.

33. A cartridge according to claim 32, wherein At least one of the convex portion and the concave portion has a twisted shape.

34. A cartridge according to claim 33, wherein The male portion has a generally triangular cross-section taken along a plane perpendicular to the male portion's axis of rotation.

35. The cartridge of claim 8, wherein: The coupling comprises: (i) a first coupling portion; and (ii) a second coupling portion configured to receive a driving force from the first coupling portion, the second coupling portion comprising an engagement portion of the coupling; Therein, the first coupling part can be partially rotated about the coupling member rotation axis relative to the second coupling part.

36. The cartridge of claim 35, further comprising a pressing member configured to press the first coupling portion to rotate the first coupling portion relative to the second coupling portion.

37. A cartridge according to claim 35 or 36, wherein The first coupling portion is rotatable relative to the second coupling portion by an angle not less than 120°.

38. The cartridge of claim 31, further comprising a pushing member configured to push the coupling to tilt the coupling relative to a rotation axis of the support member.

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