Image forming apparatus and cartridge

Abstract

To provide a technique to allow stable toner remaining amount detection, with less influence on an apparatus layout.SOLUTION: An image forming apparatus comprises a detection unit that has a light emitting unit, and a light receiving unit receiving light emitted from the light emitting unit, the light passing through a light transmission unit attached to a frame body of a developing unit, passing through the inside of a toner storage unit in the frame body of the developing unit, and exiting to the outside of the toner storage unit, and that sends a detection signal according to the quantity of light received by the light receiving unit. The light transmission unit has a first light guide unit that guides the light emitted by the light emitting unit to the inside of the toner storage unit, and a second light guide unit that guides the light passing through the inside of the toner storage unit to the light receiving unit. The image forming apparatus has a cover member that covers the first light guide unit and the second light guide unit. A portion of the second light guide unit in most proximity to a passage area through which a laser beam from an exposure unit passes is located closer to the passage area than any portions of the first light guide unit. The cover member is configured not to cover the most proximate portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus using an electrophotographic image forming process, and to a cartridge that is detachably mountable to the main body of the image forming apparatus. [Background technology]

[0002] In an image forming apparatus using an electrophotographic image forming process, in order to continue long-term use, it is necessary to grasp the amount of toner (developer) consumed and to replenish toner as appropriate, and various methods have been proposed so far as a means for detecting the amount of remaining toner contained in a toner container. In particular, in a cartridge-type apparatus in which an image forming means is made into a cartridge such as a developing cartridge or a process cartridge and is detachably attached to the main body of the apparatus, toner remaining amount detection is used as a means for grasping the time to replace the cartridge (Patent Documents 1 and 2).

[0003] A known method for detecting the remaining amount of toner is to construct a part of a frame having a toner storage section from a light-transmitting member, and detect the amount of toner in the toner storage section based on the change in the amount of detection light that passes through the inside of the toner storage section through the light-transmitting member. For example, it is possible to detect or predict the remaining amount of toner based on the fact that the degree (e.g., time) to which the detection light is blocked by the toner in the toner storage section changes depending on the remaining amount of toner.

[0004] Patent Document 1 proposes one configuration of a remaining toner detection means in a cartridge-type image forming device. In the configuration of Patent Document 1, a light-emitting unit such as an LED and a light-receiving unit such as a phototransistor are provided in the device body, and a light guide is incorporated in the cartridge frame as a light-transmitting member that guides detection light into the toner storage unit and guides the detection light that has passed through the toner storage unit to the light-receiving unit.

[0005] Patent Document 2 proposes a configuration in which the light-transmitting member is covered with a non-light-transmitting cover member in order to prevent the reflected light of the detection light from being detected by other light-receiving elements provided in the device body, thereby causing the device to malfunction. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-167490 A [Patent Document 2] JP 2009-288304 A Summary of the Invention [Problem to be solved by the invention]

[0007] Providing a cover member as a method for preventing erroneous detection by other light receiving elements requires space for the cover member, which raises concerns that securing this space could lead to an increase in the size of the cartridge, or that it could result in a reduction in the capacity of the toner storage section in order to avoid an increase in size, thereby preventing an increase in the capacity of the toner storage section in a small cartridge.

[0008] An object of the present invention is to provide a technique that enables stable detection of remaining toner amount with minimal impact on the layout of the device. [Means for solving the problem]

[0009] In order to achieve the above object, an image forming apparatus according to the present invention comprises: A photosensitive drum; an exposure unit that exposes the photosensitive drum; a developing unit including a frame having a toner storage unit, a developing roller that develops an electrostatic image formed on the photosensitive drum by the laser light of the exposure unit using the toner stored in the toner storage unit, and a light transmitting unit attached to the frame; a light-emitting section; and a light-receiving section that receives light emitted from the light-emitting section, the light-receiving section passing through the inside of the toner storage section and emerging outside the toner storage section, and that transmits a detection signal according to the amount of light received by the light-receiving section; Equipped with The light transmitting portion is a first light guiding portion that guides the light emitted by the light emitting portion into the inside of the toner containing portion; a second light guiding portion that guides the light that has passed through the interior of the toner storage portion to the light receiving portion; having An image forming apparatus having a cover member for covering the first light guiding section and the second light guiding section, a portion of the second light guiding section that is closest to a passage region through which the laser light passes is located closer to the passage region than any portion of the first light guiding section; The cover member is configured so as not to cover the closest portion. In order to achieve the above object, the cartridge of the present invention comprises: A cartridge detachably mountable to a main body of an image forming apparatus, A developing roller; a frame having a toner storage portion; a first light guiding section attached to the frame that guides light for detecting an amount of toner contained in the toner containing section from an outside of the toner containing section to an inside of the toner containing section; a second light guiding portion attached to the frame for guiding the light having passed through the inside of the toner storage portion to the outside of the toner storage portion; a cover member that covers the first light guiding portion and the second light guiding portion; In a cartridge comprising: a portion of the second light guiding section that is closest to a passing area through which a laser beam for exposing a photosensitive drum of an exposure section provided in the device body passes is located closer to the passing area than any portion of the first light guiding section; The cover member is configured so as not to cover the closest portion. Effect of the Invention

[0010] According to the present invention, it is possible to stably detect the amount of remaining toner with little effect on the layout of the device. [Brief description of the drawings]

[0011] [Figure 1] 2A and 2B are a perspective view and a cross-sectional view of a process cartridge and a main portion of a printer body. [Diagram 2] FIG. 1 is a cross-sectional view showing an outline of a laser printer. [Diagram 3] FIG. 2 is a front view illustrating an outline of the process cartridge. [Figure 4] FIG. 2 is a cross-sectional view illustrating an outline of a process cartridge. [Diagram 5] 4 is a cross-sectional view showing a second waste toner transport path of the process cartridge. FIG. [Figure 6] 4 is a cross-sectional view showing a supply port of the process cartridge. FIG. [Figure 7] FIG. 2 is an exploded perspective view of the process cartridge. [Figure 8] 5 is a schematic side view showing contact and separation of a developing unit with respect to a photosensitive drum in the process cartridge. FIG. [Figure 9] FIG. 2 is a front view showing an outline of the toner cartridge. [Figure 10] 2 is a cross-sectional view showing a toner supplying portion of the toner cartridge. FIG. [Figure 11] 4 is a cross-sectional view showing a waste toner recovery section of the toner cartridge. FIG. [Figure 12] FIG. [Figure 13] FIG. 2 is a schematic perspective view showing how a process cartridge and a toner cartridge are attached to a printer body. [Figure 14] 2 is a schematic side view showing the installation of a process cartridge and a toner cartridge in a printer body. FIG. [Figure 15] 3A and 3B are a top view and a cross-sectional view of a main portion of the process cartridge. [Figure 16] 3A and 3B are an exploded perspective view and an enlarged view of a main portion of the developing unit. [Figure 17] 3A and 3B are a top view and a cross-sectional view of the process cartridge and the main part of the printer body. [Figure 18]FIG. 2 is a schematic diagram illustrating the process cartridge and the printer body with key parts removed for installation. [Figure 19] 3A and 3B are a perspective view and a cross-sectional view of a main portion of a developing unit. [Figure 20] FIG. 2 is a circuit diagram showing the basic configuration of a remaining toner sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the mode for carrying out the present invention will be described in detail by way of example based on the embodiments with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not limited to the following embodiments. Furthermore, not all of the features described in the following embodiments are necessarily essential to the solution of the invention.

[0013] The following describes an example in which the present invention is applied to an electrophotographic image forming apparatus. An electrophotographic image forming apparatus is an apparatus that forms an image on a recording medium using an electrophotographic image forming method. Examples of electrophotographic image forming apparatuses include electrophotographic copying machines, electrophotographic printers (LED printers, laser beam printers, etc.), facsimile machines, and word processors.

[0014] [Example 1] <Image forming device> The configuration of an image forming apparatus P according to a first embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view showing a schematic configuration of the image forming apparatus P, which is a laser printer that forms (records) an image on a sheet S as a recording material. As shown in Fig. 2, the image forming apparatus P is made up of a printer main body A, a process cartridge B, and a toner cartridge C.

[0015] The printer main body A is provided with a sheet feeding section 103, a transfer roller 104, a fixing section 105, and a laser scanner 101. A process cartridge B and a toner cartridge C are detachably disposed in the printer main body A, which serves as the main body of the image forming apparatus P. The process cartridge B and the toner cartridge C are each configured to be detachably attached to the printer main body A. The details of the attachment and detachment configuration of the process cartridge B and the toner cartridge C to the printer main body A will be described later.

[0016] The process cartridge B includes a photosensitive drum 11 as an image carrier and a charging roller 12 as a charging member. When the process cartridge B is mounted in the printer main body A, the photosensitive drum 11 comes into contact with a transfer roller 104 as a transfer member to form a nip portion together with the transfer roller 104.

[0017] <Image formation operation> Next, an image forming operation of the image forming apparatus P will be described. The driven photosensitive drum 11 is uniformly charged to a predetermined potential by the charging roller 12. After being charged, the surface of the photosensitive drum 11 is exposed to laser light based on image information irradiated from a laser scanner 101 serving as a laser unit (exposure section), and the charge in the exposed portion is removed to form an electrostatic latent image (electrostatic image). When toner as a developer is supplied from a developing roller 16 serving as a developer carrier to the electrostatic latent image on the photosensitive drum 11, the electrostatic latent image is visualized as a toner image (developer image).

[0018] In parallel with the toner image forming operation, the sheet S is conveyed by the sheet feeding unit 103. The sheet feeding unit 103 includes a paper feed tray 103a and a feed roller 103b, and the sheet S is fed from the paper feed tray 103a by rotating the feed roller 103b. The sheet S is conveyed to a nip portion between the photosensitive drum 11 and the transfer roller 104 in accordance with the timing of forming a toner image on the photosensitive drum 11. When the sheet S passes through the nip portion, the toner image formed on the photosensitive drum 11 is transferred onto the sheet S as an unfixed image by applying a bias to the transfer roller 104. The sheet S onto which the unfixed image has been transferred is conveyed to a fixing unit 105. When the sheet S passes through the fixing unit 105, the unfixed image is heated and pressurized to be fixed onto the surface of the sheet S. Thereafter, the sheet S is conveyed by the sheet feeding unit 103, discharged to and stacked on a discharge tray 106, and a series of image forming operations is completed.

[0019] <Process cartridge B> The process cartridge B according to the first embodiment will be described in more detail with reference to Figs. 3, 4, 5, and 6. First, the internal structure of the process cartridge B will be described. Fig. 3 is a front view of the process cartridge B mounted in the printer main body A, as viewed from the rear side of the printer main body A toward the front side, showing the appearance of the process cartridge B. Fig. 4 is a cross-sectional view taken along line aa in Fig. 3, showing a cross-section perpendicular to the longitudinal direction of the process cartridge B. Fig. 5 is a cross-sectional view taken along line bb in Fig. 3, showing a cross-section passing through the second waste toner conveying passage 10c and perpendicular to the longitudinal direction of the process cartridge B. Fig. 6 is a cross-sectional view taken along line cc in Fig. 3, showing a cross-section passing through the supply port 21c of the process cartridge B and perpendicular to the longitudinal direction of the process cartridge B. The longitudinal direction of the process cartridge B is parallel to the rotational axis direction of the photosensitive drum 11, the developing roller 16, and the like.

[0020] Below, the X, Y, and Z directions are defined based on the posture of the process cartridge B and toner cartridge C when they are installed in the printer main body A. The Y direction is parallel to the longitudinal direction of the process cartridge B and toner cartridge C, the Z direction is the vertical direction (direction of gravity), and the X direction is perpendicular to the Z and Y directions.

[0021] The process cartridge B is composed of a cleaning unit 10 (first unit) and a developing unit 15 (second unit). The cleaning unit 10 includes a photosensitive drum 11 and can also be considered as a photosensitive unit. The developing unit 15 as a developing portion includes a developing roller 16 as a developing means for carrying a developer, and supplies toner as a developer to the photosensitive drum 11 of the cleaning unit 10.

[0022] The cleaning unit 10 has a photosensitive drum 11, a cleaning blade 17 as a cleaning member for the photosensitive drum 11, a charging roller 12 as a charging member, and a charging roller cleaner 14 as a cleaning member for the charging roller 12. The cleaning unit 10 also has a waste toner storage section 10a, a first waste toner transport path 10b, and a second waste toner transport path 10c formed therein.

[0023] The charging roller 12 is disposed so as to be in contact with the outer peripheral surface of the photosensitive drum 11. The charging roller 12 charges the photosensitive drum 11 by applying a voltage from a high-voltage power source (not shown). The charging roller 12 rotates in accordance with the rotation of the photosensitive drum 11.

[0024] The cleaning blade 17 is an elastic member disposed so as to come into contact with the outer peripheral surface of the photosensitive drum 11. The cleaning blade 17 removes toner remaining on the surface of the photosensitive drum 11 after the sheet S has passed between the photosensitive drum 11 and the transfer roller 104 from the photosensitive drum 11 by bringing its tip into elastic contact with the photosensitive drum 11. The removed toner (waste toner) is transported from the waste toner storage unit 10a to the toner cartridge C through the first waste toner transport path 10b and the second waste toner transport path 10c.

[0025] As shown in FIG. 6, the developing unit 15 has a developing frame 503 to which the developing roller 16 is rotatably attached and the developing blade 18 is fixed. The developing frame 503 has, as toner containing sections, a developing chamber 151 in which the developing roller 16 is disposed, a toner containing chamber 152 that supplies toner to the developing chamber 151, and a toner receiving chamber 153 that receives toner supplied from a toner cartridge C. The developing roller 16 supplies toner to the developing area of ​​the photosensitive drum 11, and develops the electrostatic latent image formed on the photosensitive drum 11. The developing blade 18 contacts the circumferential surface of the developing roller 16 to regulate the amount of toner that adheres to the circumferential surface of the developing roller 16. The developing blade 18 also imparts a triboelectric charge to the toner.

[0026] A stirring member 154 is rotatably provided inside the toner storage chamber 152. The toner stored in the toner storage chamber 152 is sent to the developing chamber 151 by the rotation of the stirring member 154, and is supplied to the developing roller 16.

[0027] The amount of toner remaining in the toner storage chamber 152 is detected by a remaining amount detection unit. The details of the remaining amount detection unit will be described later. When the amount of toner in the toner storage chamber 152 falls below a certain amount, an appropriate amount of toner is supplied from the toner cartridge C to the process cartridge B. The toner supplied to the developing unit 15 is received by the toner receiving chamber 153 through the supply port 21c and the delivery port 21d of the stay 21 of the process cartridge B, and is then stored in the toner storage chamber 152.

[0028] The configuration of the process cartridge B according to the first embodiment will be described in more detail with reference to Figs. 4, 7(a), 7(b), 8(a), and 8(b). Figs. 7(a) and 7(b) are exploded perspective views of the process cartridge B. Fig. 7(a) is a view of the process cartridge B seen from one end side in the longitudinal direction, and Fig. 7(b) is a view of the process cartridge B seen from the other end side in the longitudinal direction. Figs. 8(a) and 8(b) are schematic side views showing the contact state and the separation state of the developing unit 15 with respect to the photosensitive drum 11 in the process cartridge B, and are views of the process cartridge B seen in the longitudinal direction. Fig. 8(a) shows the state in which the developing roller 16 of the developing unit 15 is in contact with the photosensitive drum 11, and Fig. 8(b) shows the state in which the developing roller 16 of the developing unit 15 is separated from the photosensitive drum 11.

[0029] 7(a) and 7(b), the cleaning unit 10 is composed of a cleaning frame 20, a stay 21, and a side cover 7. The cleaning frame 20 supports a cleaning blade 17, a charging roller 12, and a charging roller cleaner 14. The photosensitive drum 11 is rotatably supported at one end in the rotation axis direction by a drum pin 22 attached to the cleaning frame 20, and at the other end by a photosensitive drum support portion 7b provided on the side cover 7.

[0030] Bearing members 4 and 5 are disposed at both ends of the developing unit 15 in the longitudinal direction (the direction of the rotation axis of the developing roller 16). The developing unit 15 is connected to the cleaning unit 10 so as to be rotatable about a swing axis 8 defined by a straight line including support shafts 8a and 8b. The swing axis 8 is an axis parallel to the rotation axis 11b of the photosensitive drum 11.

[0031] A detailed description will be given of a configuration in which the developing unit 15 is supported by the cleaning unit 10. As shown in Fig. 7(a), the bearing member 5 has a cylindrical shape 5a that is supported in a cylindrical hole shape 7a provided in the side cover 7 of the cleaning unit 10. The support shaft 8a is defined by a common axis of the cylindrical hole shape 7a of the side cover 7 and the cylindrical shape 5a of the bearing member 5.

[0032] 7(b), the pin 6 is inserted so as to straddle the cylindrical hole shape 20a of the cleaning frame 20 and the cylindrical hole shape 4a of the bearing member 4. The shaft 8b is defined by a common axis of the pin 6 and the cylindrical hole shape 4a of the bearing member 4. The shafts 8a and 8b are disposed approximately coaxially, and the swing axis 8 is defined by a straight line including the shafts 8a and 8b as described above.

[0033] With the above-mentioned configuration, the developing unit 15 is supported to be rotatable about the swing axis 8 relative to the cleaning unit 10. The biasing forces of the pressure springs 19a and 19b, which are elastic members, act between the developing unit 15 and the cleaning unit 10, and the developing roller 16 is brought into contact with the photosensitive drum 11 by the biasing forces.

[0034] An upper boss 93 and a lower boss 95 are provided at one end in the longitudinal direction of the process cartridge B, and an upper boss 94 and a lower boss 96 are provided at the other end. These function as guided portions when the process cartridge B is mounted in the printer main body A. In addition, a toner cartridge positioning portion 21a and a toner cartridge positioning portion 21b are provided on the stay 21 of the process cartridge B. These positioning portions 21a, 21b are provided for positioning the process cartridge B with respect to the toner cartridge C.

[0035] The operation of the developing unit 15 to move toward and away from the cleaning unit 10 will be described with reference to Figures 8(a) and 8(b). Note that in order to show the moving mechanism 100 of the printer main body A, the side cover 7 is omitted from Figures 8(a) and 8(b).

[0036] A protrusion 5b is provided on the bearing member 5. As shown in Fig. 8(a) , when the developing roller 16 is in contact with the photosensitive drum 11, the protrusion 5b is in a position where it does not come into contact with the separating mechanism 100. The positions of the developing roller 16 and the photosensitive drum 11 at this time correspond to an image forming position where the electrostatic latent image formed on the surface of the photosensitive drum 11 by the developing roller 16 is developed.

[0037] 8(b), when the spacing mechanism 100 provided in the printer main body A moves and comes into contact with the protruding portion 5b, the protruding portion 5b receives a force from the spacing mechanism 100. Then, the developing unit 15 rotates in the direction of arrow R1 about the swing axis 8 as the rotation center, and the photosensitive drum 11 and the developing roller 16 are separated from each other. The positions of the developing roller 16 and the photosensitive drum 11 at this time become a non-image forming position, retracted from the image forming position.

[0038] When the separating mechanism 100 returns to its original position before contacting the protruding portion 5b and separates from the protruding portion 5b, the developing unit 15 receives a biasing force in the direction opposite to the direction of the arrow R1 from the pressure springs 19a and 19b. Due to the action of this biasing force, the developing unit 15 rotates in the direction opposite to the direction of the arrow R1, and the developing roller 16 and the photosensitive drum 11 come into contact with each other.

[0039] With the above configuration, the attitude of the developing unit 15 in the process cartridge B is changed by the spacing mechanism 100, and the photosensitive drum 11 and the developing roller 16 are switched between the contact position (image forming position) and the spacing position (non-image forming position). This makes it possible to suppress toner deterioration and unnecessary toner consumption when no image is formed.

[0040] <Toner Cartridge C> The toner cartridge C according to the first embodiment will be described in more detail with reference to Figs. 9, 10, 11, 12(a) and 12(b). Fig. 9 is a front view of the toner cartridge C mounted in the printer main body A, as viewed from the rear side of the printer main body A toward the front side, showing the appearance of the toner cartridge C. Fig. 10 is a dd cross-sectional view of Fig. 9, showing a cross-section perpendicular to the longitudinal direction of the toner cartridge C passing through the toner supplying section 30. Fig. 11 is an ee cross-sectional view of Fig. 9, showing a cross-section perpendicular to the longitudinal direction of the toner cartridge C passing through the waste toner collecting section 40. Figs. 12(a) and 12(b) are exploded perspective views of the toner cartridge C. Fig. 12(a) is a view of the toner cartridge C viewed from one end side in the longitudinal direction, and Fig. 12(b) is a view of the toner cartridge C viewed from the other end side in the longitudinal direction. In addition, the longitudinal direction of the toner cartridge C is parallel to the direction of the rotation axis of the photosensitive drum 11 etc. in a state in which the process cartridge B and the toner cartridge C are mounted in the printer main body A.

[0041] 10 and 11, the toner cartridge C has a toner supplying unit 30 that supplies toner to the process cartridge B, and a waste toner collecting unit 40 that collects waste toner from the process cartridge B. The toner supplying unit 30 and the waste toner collecting unit 40 are disposed adjacent to each other in the longitudinal direction of the toner cartridge C.

[0042] 10, the toner supply unit 30 has a supply unit frame 31 and a supply unit lid 32. In the toner supply unit 30, a toner storage unit 30a that stores toner therein is formed by the supply unit frame 31 and the supply unit lid 32. In the supply unit frame 31, a toner discharge port 31a that discharges toner from the toner storage unit 30a is formed, and a shutter member 34 configured to be able to open and close the toner discharge port 31a outside the supply unit frame 31 is provided. The shutter member 34 opens and closes by rotating in the direction of arrow R2 in conjunction with the installation of the toner cartridge C.

[0043] The toner storage section 30a has a screw member 35 that transports the toner toward the toner discharge port 31a, and a stirring and transporting unit 36 ​​that transports the toner toward the screw member 35. The toner transported to the toner discharge port 31a is discharged from the toner discharge port 31a due to a volume change of a pump 37a described later.

[0044] 12(a) and 12(b), the toner supplying section 30 has a pump unit 37. The pump unit 37 has a pump 37a that changes the volume by expanding and contracting, a cam 37b that expands and contracts the pump 37a by rotating, and a link arm 37c.

[0045] The toner supply section 30 further includes an agitation drive input section 38 that drives the agitation transport unit 36 ​​, and a pump / screw drive input section 39 that drives the pump unit 37 and the screw member 35 .

[0046] 11, waste toner recovery unit 40 has waste toner storage unit 40a formed by waste toner storage unit frame 41 and waste toner storage lid 42. Waste toner receiving opening 42a is provided in waste toner storage lid 42. Waste toner recovery unit 40 has waste toner shutter member 43 that opens and closes waste toner receiving opening 42a. Waste toner shutter member 43 is opened and closed in the direction of arrow R3 in conjunction with the attachment and detachment of toner cartridge C to and from printer main body A.

[0047] As shown in Figures 11 and 12(a), a partition member 46, a first waste toner storage screw 44, and a second waste toner storage screw 47 are arranged in the waste toner recovery section 40. The first waste toner storage screw 44 transports the waste toner that has fallen from the waste toner receiving opening 42a in the longitudinal direction of the toner cartridge C. The second waste toner storage screw 47 transports the waste toner that has fallen from the waste toner receiving opening 42a in the longitudinal direction of the toner cartridge C. A driving force is transmitted from the first waste toner collecting screw 44 to transport the waste toner transported by the first waste toner collecting screw 44 obliquely upward.

[0048] The drive mechanism of the waste toner recovery section 40 will be described. The drive force input from the stirring drive input section 38 of the toner supply section 30 is transmitted to the non-drive side gear 38a provided on the non-drive side of the toner supply section 30 via the stirring transport unit 36. The drive force is then transmitted from the non-drive side gear 38a to the first waste toner storage screw 44 via the waste toner storage section gear train 45.

[0049] A driving side cover 50 is attached to the end of the toner cartridge C facing the toner supply unit 30, and a non-driving side cover 60 is attached to the end of the toner cartridge C facing the waste toner collection unit 40. The driving side cover 50 has a positioning boss 50a and a guided portion 50b. Similarly, the non-driving side cover 60 has a positioning boss 60a and a guided portion 60b. The guided portions 50b, 60b function as guided portions when the toner cartridge C is attached to the printer main body A. The positioning bosses 50a, 60a are provided to position the toner cartridge C with respect to the process cartridge B.

[0050] With the above configuration, even when the pump screw drive input portion 39 is not driven, the agitation drive input portion 38 can be driven. In other words, even when the toner supplying portion 30 is not replenishing toner to the process cartridge B, the first waste toner storage screw 44 and the second waste toner storage screw 47 in the waste toner collecting portion 40 can be driven to maintain a state in which waste toner can be collected.

[0051] Furthermore, according to the configuration of the first embodiment, the drive can be input from the printer main body A to one end of the toner cartridge C in the longitudinal direction, thereby simplifying the gear train configuration of the printer main body A. Furthermore, by using the stirring and transporting unit 36 ​​to transmit the drive from one end to the other end of the supply unit frame 31, the drive can be transmitted to the waste toner recovery unit 40 without increasing the number of parts for drive transmission. With this configuration, the drive means of the toner cartridge C can be configured to accommodate waste toner in the toner cartridge C while preventing the toner cartridge C and the printer main body A from becoming larger.

[0052] <How to install and remove the process cartridge B and toner cartridge C> A method of mounting and dismounting the process cartridge B and the toner cartridge C to the printer main body A will be described with reference to Figs. 7(a), 7(b), 12(a), 12(b), 13(a), 13(b), and 14(a) to 14(c). Figs. 13(a) and 13(b) are schematic perspective views for explaining a method of mounting the process cartridge B and the toner cartridge C to the printer main body A. Fig. 13(a) shows how the process cartridge B is mounted to the printer main body A, and Fig. 13(b) shows how the toner cartridge C is mounted to the printer main body A. Fig. 14 is a schematic side view for explaining a method of mounting the process cartridge B and the toner cartridge C to the printer main body A. Figure 14(a) shows the state in which process cartridge B is installed in the printer body A, Figure 14(b) shows the state in which toner cartridge C is installed in the printer body A (printer body A with process cartridge B installed), and Figure 14(c) shows the state in which both process cartridge B and toner cartridge C are installed in the printer body A.

[0053] As shown in Fig. 13(a), a space (mounting space) is formed inside the printer main body A for locating the mounted process cartridge B and toner cartridge C. The opening / closing door 107 is provided so as to be rotatable in the direction of arrow R4 about a rotation axis relative to the printer main body A, and Fig. 13(a) shows the opening / closing door 107 in an open state.

[0054] The printer main body A has guide portions 108 and 109 for guiding the process cartridge B and the toner cartridge C. The process cartridge B has an upper boss 93 and a lower boss 95 at one end in the longitudinal direction as shown in FIG. 7(b), and has an upper boss 94 and a lower boss 96 at the other end as shown in FIG. 7(a). The toner cartridge C has a positioning boss 50a and a guided portion 50b at one end in the longitudinal direction as shown in FIG. 12(a), and has a positioning boss 60a and a guided portion 60b at the other end as shown in FIG. 12(b). The positioning bosses 50a and 60a are provided downstream (forward) of the guided portions 50b and 60b in the mounting direction of the toner cartridge C.

[0055] First, a method of mounting the process cartridge B into the printer body A will be described. The process cartridge B is inserted into the printer body A with the upper boss 93 and the lower boss 95 sandwiching the guide portion 108 of the printer body A, and with the upper boss 94 and the lower boss 96 sandwiching the guide portion 109 of the printer body A. By this insertion method, the process cartridge B is inserted in the direction of the arrow D while being guided by the guide portions 108 and 109.

[0056] Next, a method for mounting the toner cartridge C in the printer main body A will be described. The toner cartridge C is mounted in the printer main body A after the process cartridge B is mounted in the printer main body A. As shown in Fig. 7(b), the stay 21 of the process cartridge B has a toner cartridge positioning portion 21a for positioning the toner cartridge C and a toner cartridge positioning portion 21b.

[0057] The toner cartridge C is inserted into the printer main body A with the guided portion 50b resting on the guide portion 109 and the guided portion 60b resting on the guide portion 108. By this insertion method, the toner cartridge C is inserted in the direction of the arrow D while being guided by the guide portions 108 and 109.

[0058] As shown in Fig. 14(c), when the toner cartridge C is mounted to the insertion completion position, the positioning bosses 50a and 60a enter the toner cartridge positioning portions 21a and 21b. At this time, the leading ends of the guided portions 50b and 60b in the insertion direction are separated from the guide portions 108 and 109, and their rear ends come into contact with the guide portions 108 and 109. This positions the toner cartridge C in the process cartridge B. Furthermore, the rear ends of the guided portions 50b and 60b come into contact with the guide portions 108 and 109, thereby determining the position of the toner cartridge C in the printer main body A.

[0059] Thereafter, when the opening and closing door 107 is closed after inserting the process cartridge B and the toner cartridge C, the image forming apparatus P is ready for image formation. When removing the toner cartridge C and the process cartridge B from the printer main body A, the above steps are reversed.

[0060] <Toner remaining amount detection unit> The image forming apparatus P according to this embodiment is provided with a toner remaining amount detection unit that detects the amount of toner remaining in the toner storage chamber 152 serving as the toner storage unit of the process cartridge B. The toner remaining amount detection unit in this embodiment is a light transmission type remaining amount detection unit, and is generally composed of a light emitting unit and a light receiving unit provided in the printer main body A, and a light transmitting unit provided in the frame of the process cartridge B.

[0061] <Explanation of the light transmitting part (light guide)> 15(a), 15(b), 1(a), 1(b), 16(a) and 16(b), the toner remaining amount detection unit of the present embodiment includes a light transmission element for the process cartridge B. The configuration of the unit will be described.

[0062] FIG. 15(a) shows the process cartridge B when viewed in the opening direction of the opening 504 provided in the process cartridge B for passing the laser light of the laser scanner 101 toward the photosensitive drum 11. FIG. 15(b) shows a cross section passing through the detection portion 501g of the light guide 501 when the process cartridge B is viewed in the longitudinal direction (xx cross section). FIG. 1(a) is a yy cross section of FIG. 15(a), showing the light input portion 501a which is the entrance portion of the light guide 501, and the light output portion 501f which is the exit portion. FIG. 1(b) is an enlarged view of the area W shown in FIG. 1(a). FIG. 16(a) is an exploded perspective view showing the light guide cover 502 which is a cover member in an exploded state. FIG. 16(b) is an enlarged view of the area V shown in FIG. 16(a).

[0063] A light guide 501 and a light guide cover 502 that covers a part of the light guide 501 are provided on the developing frame 503 of the developing unit 15 of the process cartridge B. The light guide 501 is made of a light-transmitting material (for example, a light-transmitting resin such as transparent acrylic) and is integrally built into the developing frame 503. The light guide 501 is a light-transmitting member in which a guide path for guiding detection light is formed and through which the detection light for detecting the remaining amount of toner in the toner storage chamber 152 passes.

[0064] The guide path of the light guide 501 is composed of a light input portion 501a, a first input straight portion 501b1, a second input straight portion 501b2, an inner-chamber emission surface 501c, an inner-chamber light receiving surface 501d, a first output straight portion 501e1, a second output straight portion 501e2, a light output portion 501f, etc. In addition to the above-mentioned portions constituting the guide path, the light guide 501 is an integral member including a detection portion 501g for forming a passing portion 501h inside the toner storage chamber 152.

[0065] More specifically, the guide path of the light guide 501 is composed of a first light guiding portion 5011 that guides the detection light to the toner storage portion of the developing frame 503, and a second light guiding portion 5012 that guides the detection light that has passed through the toner storage portion to the light receiving portion.

[0066] The first light guide 5011 has a light input portion 501a as a first entrance portion that takes in the detection light from the outside of the developing frame 503. In this embodiment, the detection light emitted by the LED 451a as a light emitting portion provided in the printer main body A enters the light input portion 501a. The first light guide 5011 also has an inner chamber exit surface 501c as a first exit portion that exits the detection light entering from the light input portion 501a toward the inside of the toner storage portion. The toner storage portion is composed of the developing chamber 151, the toner storage chamber 152, the toner receiving chamber 153, etc., and in this embodiment, the detection light enters the toner storage chamber 152 from the inner chamber exit surface 501c. The first light guide 5011 also has a first guide portion 501b that connects between the light input portion 501a and the inner chamber exit surface 501c. The first guide portion 501b includes a first input straight portion 501b1 as a first straight portion, and a second input straight portion 501b2 perpendicular to the first input straight portion 501b1. The detection light is guided from the light input portion 501a to the accommodation chamber inner emission surface 501c through the first input straight portion 501b1, the second input straight portion 501b2, etc.

[0067] The second light guiding section 5012 has, as a second entrance section, an internal light receiving surface 501d on which the detection light that has passed through the toner storage chamber 152 as the inside of the toner storage section is incident. The second light guiding section 5012 also has, as a second exit section, a light output section 501f that outputs the detection light that has entered the internal light receiving surface 501d toward the outside of the developing frame 503. In this embodiment, the light output section 501f outputs the detection light toward a phototransistor 451b that serves as a light receiving section and detection section provided in the printer main body A. The second light guiding section 5012 also has a second guide section 501e that connects between the internal light receiving surface 501d and the light output section 501f. The second guide section 501e is The light output unit 501f includes a first output straight portion 501e1 and a second output straight portion 501e2 that is a second straight portion perpendicular to the first output straight portion 501e1. The detection light is guided from the light receiving surface 501d inside the accommodation chamber to the light output unit 501f through the first output straight portion 501e1 and the second output straight portion 501e2.

[0068] The light input portion 501a of the first light guiding portion 5011 and the light output portion 501f of the second light guiding portion 5012 are each disposed at one end (first end portion) of the developing frame 503 in the direction of the rotation axis of the developing roller 16 (longitudinal direction of the developing frame 503). The light input portion 501a and the light output portion 501f are disposed so as to be aligned in a direction perpendicular to the longitudinal direction at approximately the same position in the longitudinal direction. The light output portion 501f is disposed at a position closer to a passing area of ​​the laser light of the laser scanner 101 (described later) than the light input portion 501a. The light output portion 501f is also disposed at a position closer to the photosensitive drum 11 than the light input portion 501a.

[0069] The chamber interior light exit surface 501c of the first light guide portion 5011 and the chamber interior light receiving surface 501d of the second light guide portion 5012 are disposed closer to the other end (second end) opposite to the one end (first end) than the light input portion 501a and the light output portion 501f in the longitudinal direction. The chamber interior light exit surface 501c is located closer to the one end (first end) than the chamber interior light receiving surface 501d, and the chamber interior light exit surface 501c and the chamber interior light receiving surface 501d are disposed to be aligned along the longitudinal direction. In addition, the chamber interior light exit surface 501c and the chamber interior light receiving surface 501d are disposed at different positions in the direction perpendicular to the longitudinal direction relative to the light input portion 501a and the light output portion 501f. The storage chamber inner light-emitting surface 501c and the storage chamber inner light-receiving surface 501d are disposed at a position farther from a passing area of ​​a laser beam from the laser scanner 101, which will be described later, than the light input unit 501a and the light output unit 501f. Also, the storage chamber inner light-emitting surface 501c and the storage chamber inner light-receiving surface 501d are disposed at a position farther from the photosensitive drum 11 than the light input unit 501a and the light output unit 501f.

[0070] The first guide portion 501b includes a first input straight portion 501b1 and a second input straight portion 501b2 to connect between the light input portion 501a and the inner emission surface 501c, which are located at different positions as described above. The first input straight portion 501b1 extends along the longitudinal direction as a first straight portion downstream of the light input portion 501a in the light guide path of the first guide portion 501b. The second input straight portion 501b2 extends along a direction perpendicular to the longitudinal direction downstream of the first input straight portion 501b1 in the light guide path of the first guide portion 501b.

[0071] Similarly, the second guide portion 501e includes a first output straight portion 501e1 and a second output straight portion 501e2 to connect between the inner chamber light receiving surface 501d and the light output portion 501f, which are located at different positions as described above. The first output straight portion 501e1 extends along a direction perpendicular to the longitudinal direction downstream of the inner chamber light receiving surface 501d in the light guide path of the second guide portion 501e. The second output straight portion 501e2 extends along the longitudinal direction as a second straight portion downstream of the first output straight portion 501e1 in the light guide path of the second guide portion 501e.

[0072] The first input straight portion 501b1 of the first guide portion 501b and the second output straight portion 501e2 of the second guide portion 501e extend side by side in a direction perpendicular to the longitudinal direction. The longitudinal length of the second output straight portion 501e2 is longer than the longitudinal length of the first input straight portion 501b1.

[0073] Between the inner-chamber emission surface 501c and the inner-chamber light-receiving surface 501d, a passing portion 501h provided inside the toner storage chamber 152 is located. The passing portion 501h is a space in the toner storage chamber 152 that is surrounded by the detection portion 501g of the light guide 501. In other words, a part of the wall portion of the developing frame 503 that forms the toner storage chamber 152 is configured by the detection portion 501g as part of the light guide 501.

[0074] The detection light emitted from the storage chamber exit surface 501c passes through the passing portion 501h and enters the storage chamber light receiving surface 501d. The passing portion 501h is an area to be detected by the detection light, which is sandwiched between the storage chamber exit surface 501c and the storage chamber light receiving surface 501d in the longitudinal direction in the toner storage chamber 152. The amount of the detection light emitted from the storage chamber exit surface 501c is affected by the state (amount of toner) of the toner stored in the toner storage chamber 152 (passing portion 501h) and enters the storage chamber light receiving surface 501d.

[0075] 1(a) and 1(b), a straight path along which a laser beam emitted by the laser scanner 101 based on image information ideally passes is defined as a laser path R, and an area (passing area) offset by a predetermined distance T from the laser path R is defined as an opening 504. The light guide 501 is disposed at a position between the toner storage chamber 152 and the opening 504 and in close proximity to the opening 504. The laser beam emitted from the laser scanner 101 passes beside a first input straight portion 501b1 and a second output straight portion 501e2 of the light guide 501, and is irradiated onto the photosensitive drum 11.

[0076] Here, in this embodiment, the second output straight portion 501e2 is the portion of the second light guiding portion 5012 of the light guide 501 that is closest to the passage area of ​​the laser light of the laser scanner 101. The second output straight portion 501e2 is located closer to the passage area of ​​the laser light than any portion of the first light guiding portion 5011. The extension direction of the second output straight portion 501e2 is the direction along the rotation axis of the photosensitive drum 11, and also the direction along the scanning direction of the laser light when the laser scanner 101 scans and exposes the peripheral surface of the photosensitive drum 11.

[0077] 15(b), a developing frame 503, which is a frame that forms the toner storage chamber 152 of the developing unit 15, is provided with a remaining amount detection opening 506. The guide path inside the light guide 501 communicates with the toner storage chamber 152 through the remaining amount detection opening 506.

[0078] As shown in FIG. 16(a) and FIG. 16(b), the detection light emitted from the light emitting unit of the printer main body A is input to the light input unit 501a of the light guide 501 in the direction of the arrow L1. Then, the detection light travels while being reflected on the first input straight portion 501b1 in the direction of the arrow L2 and on the second input straight portion 501b2 in the direction of the arrow L3, and reaches the inside of the toner storage chamber 152. Inside the toner storage chamber 152 of the light guide 501, the storage chamber inner exit surface 501c that emits the detection light in the direction of the arrow L4 and the storage chamber inner light receiving surface 501d that receives the detection light emitted from the storage chamber inner exit surface 501c are located along the longitudinal direction. In the first embodiment, the direction of the arrow L2 (first direction) and the direction of the arrow L4 are parallel to the longitudinal direction of the developing unit 15 (the rotation axis of the developing roller 16) or the rotation axis 11b of the photosensitive drum 11.

[0079] The detection light traveling in the direction of arrow L3 passes through the inner chamber exit surface 501c and passes through the passage portion 501h inside the toner storage chamber 152. The detection light that passes through the passage portion 501h is reflected by the inner chamber light receiving surface 501d and travels in the direction of L5 through the first output straight portion 501e1. The detection light then travels from the direction of arrow L5 while reflecting off the second output straight portion 501e2 in the direction of arrow L6, and is emitted from the light output portion 501f in the direction of arrow L7 toward a detection portion provided in the printer main body A. In the first embodiment, the direction of arrow L6 is the opposite direction (second direction) to the direction of arrow L2, and the direction of arrow L7 is the opposite direction to the direction of arrow L1.

[0080] In this way, the detection light is incident on the first light guiding portion 5011 of the light guide 501 from the light input portion 501a which is an entrance, passes through the first input straight portion 501b1 and the second input straight portion 501b2, and is directed from the inner emission surface 501c of the toner storage chamber 152 to the passage portion 501h of the toner storage chamber 152. The detection light emitted to the passing portion 501h is incident on the second light guiding portion 5012 of the light guide 501 toward the light receiving surface 501d inside the toner storage chamber, passes through the first output straight portion 501e1 and the second output straight portion 501e2, and is emitted from the light output portion 501f. In the first embodiment, the amount of toner remaining in the toner storage chamber 152 is detected based on the length of time that the toner stirred by the stirring member 154 in the passing portion 501h blocks the detection light.

[0081] <Explanation of the interface with the printer main unit A> The interface between the printer body A and the process cartridge B will be described with reference to Figs. 17(a), 17(b), 18(a) and 18(b). Figs. 17(a) and 17(b) are explanatory diagrams showing the main parts of the process cartridge B and the printer body A when the process cartridge B is mounted in the printer body A. Fig. 17(a) is a top view showing an end of the process cartridge B. Fig. 17(b) is a zz cross-sectional view of Fig. 17(a), showing a cross-section passing through the light input section 501a and the light output section 501f of the light guide 501 and perpendicular to the longitudinal direction of the process cartridge B. Figs. 18(a) and 18(b) are views of the light guide cover 502 and the optical unit 450 in the direction of the optical axis of the detection light emitted from the light output section 501f of the light guide 501 toward the printer body A. 18(a) shows the state in which the process cartridge B is being mounted to the printer main body A, and FIG. 18(b) shows the state after the process cartridge B has been mounted to the printer main body A. FIG.

[0082] As shown in Figures 17(a) and 17(b), the printer main body A is provided with an optical unit 450 constituting a remaining amount detection section for detecting the amount of toner in the toner storage chamber 152 of the process cartridge B. The optical unit 450 has a remaining amount detection board 451, a board holder 452 to which the remaining amount detection board 451 is attached, a board holder holding member 453 that holds the board holder 452, and a biasing member (spring) 454 that biases the board holder 452. When the process cartridge B is attached to the printer main body A, the optical unit 450 is located above the photosensitive drum 11 and in the vicinity of the light input portion 501a and the light output portion 501f of the light guide 501 of the process cartridge B.

[0083] 18(a) and 18(b), an LED 451a serving as a light-emitting portion (light-emitting element) that emits detection light and a phototransistor 451b serving as a light-receiving portion (light-receiving element) and detection portion that receives and detects the detection light are mounted on the remaining amount detection board 451. A toner remaining amount sensor 500 serving as a developer amount detection means in this embodiment is composed of a light guide 501, the LED 451a, and the phototransistor 451b.

[0084] Fig. 20 is a circuit diagram showing a schematic example of the circuit configuration of the toner remaining amount sensor 500 in this embodiment. As shown in the circuit diagram of the toner remaining amount sensor 500 in Fig. 20, a switch (not shown) is provided between the LED 451a and the power supply voltage Vcc. By turning on the switch, a voltage from the power supply voltage Vcc is applied to the LED 451a, and the LED 451a becomes conductive. Meanwhile, a switch (not shown) is also provided between the phototransistor 451b and the power supply voltage Vcc, and by turning on the switch, the phototransistor 451b becomes conductive due to a current corresponding to the detected light amount.

[0085] A power supply voltage Vcc and a current limiting resistor R1 are connected to the LED 451a, and the LED 451a emits light with a current determined by the current limiting resistor. The light emitted from the LED 451a passes through a passage 501h inside the toner storage chamber 152 and is received by the phototransistor 451b. A power supply voltage Vcc is connected to the collector terminal of the phototransistor 451b, and a detection resistor R2 is connected to the emitter terminal. The phototransistor 451b receives the light emitted from the LED 451a and transmits a signal (current) according to the amount of light received. This signal is converted to a voltage V1 by the detection resistor R2 as a detection signal, and is then output to the pre-transistor 451b. The signal is input to an A / D converter (not shown) of a control unit (not shown) of the printer main body A. That is, the phototransistor 451b changes the value (voltage value) of the output signal in accordance with the amount of toner (developer) contained in the toner containing chamber 152.

[0086] The control unit (CPU) of the printer main body A judges whether the phototransistor 451b has received light from the LED 451a based on the input voltage value. The control unit of the printer main body A calculates the amount of toner (amount of developer) in the toner storage chamber 152 based on the length of time that the phototransistor 451b detects each light when the toner in the toner storage chamber 152 is stirred for a certain period of time by the stirring member 154 and the intensity of the received light (amount of light). For example, the ROM provided in the control unit of the printer main body A stores in advance a table that can output the remaining amount of toner from the light reception time and light intensity when the toner is stirred and transported by the stirring member 154. The control unit of the printer main body A can predict / calculate the remaining amount of toner based on the input to the A / D conversion unit and the table.

[0087] 18(a) and 18(b) show the optical unit 450 and the light guide cover 502 when viewed from a direction perpendicular to the surface on which the LED 451a and the phototransistor 451b of the remaining amount detection board 451 are provided. When the process cartridge B is attached to the printer main body A, the detection light emitted from the LED 451a passes through the optical path inside the light guide 501 and the toner storage chamber 152, and reaches the phototransistor 451b. When the process cartridge B is not attached to the printer main body A, the LED 451a and the phototransistor 451b of the remaining amount detection board 451 are covered by the board holder holding member 453.

[0088] The substrate holder 452 is movably held by a substrate holder holding member 453, and is constantly urged in the direction of arrow H by a holder urging member 454. When the process cartridge B is not installed in the printer main body A, the substrate holder 452 is urged by the holder urging member 454 and positioned on the insertion / removal trajectory of the process cartridge B. When the process cartridge B is installed in the printer main body A, the substrate holder 452 engages with a light guide cover 502 of the process cartridge B and is positioned.

[0089] Next, the operation of the substrate holder 452 when the process cartridge B is mounted will be described. The substrate holder 452 has a contacted portion 452a that contacts the light guide cover 502 during the mounting operation of the process cartridge B, and a positioned portion 452b and a positioned portion 452c for positioning the substrate holder 452 with respect to the process cartridge B. The positioned portion 452b is a surface facing a direction intersecting with the insertion / removal direction of the process cartridge B, and is a plane substantially perpendicular to the insertion / removal direction in the first embodiment. The positioned portion 452c is a surface intersecting with the positioned portion 452b, and is a plane substantially parallel to the insertion / removal direction in the first embodiment. The contacted portion 452a is a plane intersecting with the positioned portion 452b and the positioned portion 452c, and is an inclined surface provided at the end upstream of the insertion direction of the process cartridge B.

[0090] The light guide cover 502 has a contact portion 502a that contacts the contacted portion 452a during the mounting operation of the process cartridge B, a positioning portion 502b that contacts the positioned portion 452b, and a positioning portion 502c that contacts the positioned portion 452c. The light guide cover 502 also has an input positioning portion 502d that fits with the light input portion 501a, and an output positioning portion 502e that is a hole that fits with the light output portion 501f.

[0091] Next, the movement of the board holder 452 during the mounting operation of the process cartridge B into the printer main body A will be described. As described above, when the process cartridge B is not mounted in the printer main body A, the board holder 452, which is biased in the direction of the arrow H, is located at the first position, which is on the insertion / removal trajectory of the process cartridge B. When the board holder 452 is at the first position In this state, the LED 451 a and the phototransistor 451 b of the remaining amount detection board 451 attached to the board holder 452 are covered by the board holder holding member 453 .

[0092] When the process cartridge B is inserted into the printer main body A, first the contact portion 502a of the light guide cover 502 contacts the contacted portion 452a of the substrate holder 452. Then, the substrate holder 452 receives a force from the light guide cover 502 and moves against the biasing force of the biasing member 454.

[0093] When the process cartridge B is inserted to the rear, the positioning portion 502c comes into contact with the positioned portion 452c. Then, when the process cartridge B is inserted further to the rear while the positioning portion 502c is in sliding contact with the positioned portion 452c, the positioning portion 502b comes into contact with the positioned portion 452b. Then, when the mounting of the process cartridge B is completed, the substrate holder 452 is positioned by the light guide cover 502. In this manner, during the process of mounting the process cartridge B to the printer main body A, the substrate holder 452 is pushed by the light guide cover 502 and moves from the first position to the second position. When the substrate holder 452 is in the second position, the substrate holder 452 is biased by the biasing member 454 in the direction toward the first position. With this configuration, when the process cartridge B is mounted in the printer main body A, the positioned portion 452c receives a force in the direction of arrow H1 from the positioning portion 502c, and the positioned portion 452b receives a force in the direction of arrow H2 from the positioning portion 502b.

[0094] In this way, when the process cartridge B is attached to the printer main body A and is in an image formable position, the substrate holder 452 is located at the second position and is pressed against the light guide cover 502 by the biasing member 454. Then, the substrate holder 452 receives a reaction force from the light guide cover 502 and is positioned relative to the light guide cover 502.

[0095] When the substrate holder 452 is in the second position, the LED 451a and the phototransistor 451b of the remaining toner amount detection substrate 451 attached to the substrate holder 452 are exposed. The phototransistor 451b is positioned corresponding to the light input portion 501a by the input positioning portion 502d of the light guide cover 502. Similarly, the LED 451a is positioned corresponding to the light output portion 501f by the output positioning portion 502e. With this configuration, the substrate holder 452 can be accurately positioned with respect to the light guide cover 502 and the light guide 501, thereby improving the accuracy of remaining toner amount detection.

[0096] With the above-described configuration, the light guide cover 502 has a function of covering the light input portion 501a and the light output portion 501f so that the detection light does not expose the photosensitive drum 11, and a function of positioning the substrate holder 452. Furthermore, with the configuration of the first embodiment, the risk of the detection light exposing the photosensitive drum 11 and causing deterioration in image quality is reduced, and the detection light passes through the light guide 501 with high accuracy, so that the remaining toner amount can be stably detected.

[0097] <Light guide cover explanation> A detailed configuration of the light guide cover 502, which is one of the features of this embodiment, will be described with reference to Figures 1(a), 1(b), 19(a) and 19(b). Figure 19(a) is a perspective view of the process cartridge B as seen from the side on which the light guide cover 502 is provided. Figure 19(b) is a yy cross-sectional view of Figure 19(a), showing a cross section passing through the light guide cover 502 of the process cartridge B.

[0098] As shown in FIG. 19A, a light guide cover 502 as a cover member is configured to cover each portion of the light guide 501. Specifically, the light guide cover 502 covers the light input portion 501a, the first input straight portion 501b1, the second input straight portion 501b2, and the light guide cover 502. 1b2, the detection portion 501g, the first output straight portion 501e1, and the light output portion 501f. On the other hand, the second output straight portion 501e2 is not covered by the light guide cover 502, and is exposed to the outside of the developing frame 503 when the light guide cover 502 is attached. In other words, the light guide cover 502 is configured not to cover a part of the second light guiding portion 5012, and in this embodiment, is configured not to cover the second output straight portion 501e2.

[0099] The light guide cover 502 has an input positioning portion 502d that covers the periphery of the light input portion 501a, and an output positioning portion 502e that covers the periphery of the light output portion 501f. The input positioning portion 502d and the output positioning portion 502e are positioning portions for positioning the light guide cover 502 with respect to the light guide 501. The input positioning portion 502d and the output positioning portion 502e are also protective portions that protect the light input portion 501a and the light output portion 501f, which are most important for transmitting and receiving the detection light of the light guide 501.

[0100] The light guide cover 502 is disposed above the photosensitive drum 11. The light guide cover 502 also has an input straight cover portion 502g that covers the first input straight portion 501b1, and a detection portion cover 502h that covers the detection portion 501g of the light guide 501. With this configuration, it is possible to prevent the photosensitive drum 11 from being exposed to the detection light.

[0101] In addition, the developing frame 503 has an exposure prevention portion 503a that separates the first input straight portion 501b1 and the second output straight portion 501e2. The exposure prevention portion 503a and the light guide cover 502 prevent light from entering the first input straight portion 501b1 of the light guide 501 and from leaking from the first input straight portion 501b1.

[0102] 1(b), the first input straight portion 501b1 and the second output straight portion 501e2 are disposed on the sides of the opening 504 (laser path R). The first input straight portion 501b1 and the second output straight portion 501e2 are disposed side by side in a direction intersecting with the rotation axis 11b of the photosensitive drum 11, and the first input straight portion 501b1 is located above the second output straight portion 501e2. In other words, the first input straight portion 501b1 is disposed at a position farther from the photosensitive drum 11 than the second output straight portion 501e2.

[0103] Also, the first input straight portion 501b1 is disposed at a position farther from the opening 504 (laser path R) than the second output straight portion 501e2. In other words, the light guide 501 is configured so that a first distance E1 between the first input straight portion 501b1 and the laser path R is larger than a second distance E2 between the second output straight portion 501e2 and the laser path R in a cross section perpendicular to the Y direction.

[0104] As described above, the detection light emitted from the LED 451a provided in the printer main body A enters the light guide 501 (first light guiding portion 5011) from the light input portion 501a, passes through the first input straight portion 501b1, and is emitted into the inside of the toner storage chamber 152. Then, the detection light that has passed through the toner storage chamber 152 enters the light guide 501 (second light guiding portion 5012) again, passes through the second output straight portion 501e2, and is emitted from the light output portion 501f toward the phototransistor 451b of the printer main body A. Therefore, the amount of detection light is smaller in the first output straight portion 501e1, the second output straight portion 501e2, and the light output portion 501f than in the light input portion 501a, the first input straight portion 501b1, and the second input straight portion 501b2. Therefore, for example, even if the detection light leaks from the second output straight portion 501e2 to the outside of the light guide 501, the leaked light is unlikely to reach the photosensitive drum 11, and the influence on the photosensitive drum 11 is small. The first input straight portion 501b1, the second input straight portion 501b2, and the detection portion 501g through which the detection light having a larger amount of light passes compared to 501e2 are covered by the light guide cover 502. Furthermore, as shown in FIG. 19(b), the exposure prevention portion 503a provided on the developing frame 503 covers the first input straight portion 501b1 together with the input straight cover portion 502g. With this configuration, the portion of the light guide 501 through which the detection light having a larger amount of light passes is covered by the light guide cover 502 that prevents the light from leaking to the outside, and some portions through which the detection light having a larger amount of light passes are exposed. That is, according to the configuration of the first embodiment, the area that is particularly effective for reducing the influence on the photosensitive drum 11 is covered by the light guide cover 502, and it is possible to prevent the area in which the light guide cover 502 covers the light guide 501 from becoming excessively wide.

[0105] For example, when the positions of the light input section 501a and the light output section 501f are swapped, the first input straight section 501b1 is disposed closer to the opening 504 and the photosensitive drum 11 than the second output straight section 501e2. In order to prevent the light leaking from the light guide 501 from exposing the photosensitive drum 11, it is preferable to cover the first input straight section 501b1 with the light guide cover 502 (input straight cover section 502g) as described above. However, when the input straight cover section 502g is provided to cover the first input straight section 501b1 close to the opening 504, the light guide cover 502 may enter the opening 504, and the laser may interfere with the light guide cover 502, resulting in a deterioration in image quality. In addition, when the input straight cover section 502g is provided so as not to interfere with the laser, it is necessary to increase the distance between the first input straight section 501b1 and the laser path R. In this case, it becomes necessary to take measures such as increasing the size of the process cartridge B or reducing the capacity of the toner storage chamber 152.

[0106] On the other hand, in the first embodiment, the light input portion 501a and the first input straight portion 501b1 of the light guide 501 are disposed at a position farther from the opening 504 and the photosensitive drum 11 than the light output portion 501f and the second output straight portion 501e2. The light guide cover 502 is configured to cover the first input straight portion 501b1, the light input portion 501a, and the light output portion 501f without covering the second output straight portion 501e2 disposed at a position closer to the opening 504. With this configuration, the light guide cover 502 can prevent the photosensitive drum 11 from being exposed to the detection light while preventing interference with the laser. In addition, since there is no need to provide a cover portion that covers the second output straight portion 501e2, it is possible to reduce costs and suppress a reduction in the capacity of the toner storage chamber 152 and an increase in the size of the process cartridge B.

[0107] As described above, according to this embodiment, it is possible to provide a small-sized developing unit that can have a large capacity, as well as a cartridge and an image forming apparatus that are small-sized and have a high degree of freedom in layout and are capable of stably detecting the remaining amount.

[0108] <Other Examples> The configurations of the image forming apparatus P and the process cartridge B described above are merely examples of application of the present invention, and the present invention is not limited to the above-described embodiment. Furthermore, not all of the configurations of the above-described embodiments are necessarily required for application of the present invention.

[0109] For example, in the first embodiment, the process cartridge B and the toner cartridge C are configured to be separately mounted in the printer main body A, but the process cartridge B and the toner cartridge C may be configured as an integrated cartridge. Alternatively, each element constituting the process cartridge B may be provided so as not to be detachable from the printer main body A.

[0110] In the first embodiment, the light guide 501 is made of one member, but the light guide 501 may be made of a plurality of members. For example, the light guide 501 may be made of a light transmission unit in which the light input portion 501a to the inner-chamber light-emitting surface 501c are made of one member, and the light receiving surface 501d to the inner-chamber light output portion 501f are made of another member.

[0111] The disclosure of this embodiment includes the following configuration. (Configuration 1) A photosensitive drum; an exposure unit that exposes the photosensitive drum; a developing unit including a frame having a toner storage unit, a developing roller that develops an electrostatic image formed on the photosensitive drum by the laser light of the exposure unit using the toner stored in the toner storage unit, and a light transmitting unit attached to the frame; a light-emitting section; and a light-receiving section that receives light emitted from the light-emitting section, the light-receiving section passing through the inside of the toner storage section and emerging outside the toner storage section, and that transmits a detection signal according to the amount of light received by the light-receiving section; Equipped with The light transmitting portion is a first light guiding portion that guides the light emitted by the light emitting portion into the inside of the toner containing portion; a second light guiding portion that guides the light that has passed through the interior of the toner storage portion to the light receiving portion; having An image forming apparatus having a cover member for covering the first light guiding section and the second light guiding section, a portion of the second light guiding section that is closest to a passage region through which the laser light passes is located closer to the passage region than any portion of the first light guiding section; The image forming apparatus according to claim 1, wherein the cover member is configured so as not to cover the closest portion. (Configuration 2) 2. The image forming apparatus according to claim 1, wherein the closest portion is a portion extending along a scanning direction of the laser light. (Configuration 3) 3. The image forming apparatus according to claim 1, wherein the closest portion is a portion extending along a rotation axis of the developing roller. (Configuration 4) The first light guiding section is a first incident portion into which the light emitted by the light emitting portion is incident; a first exit portion that exits the light incident from the first entrance portion toward the inside of the toner storage portion; having The second light guiding section is a second incident portion into which the light having passed through the interior of the toner storage portion is incident; a second exit portion that outputs the light incident from the second entrance portion toward the light receiving portion; having The image forming apparatus according to any one of configurations 1 to 3, characterized in that the first entrance portion and the second exit portion are each provided at a first end of the frame body in the direction of the rotation axis of the developing roller. (Configuration 5) The first exit portion and the second entrance portion are arranged between the first end portion of the frame and a second end portion opposite to the first end portion in the direction of the rotation axis such that the first exit portion is closer to the first end portion than the second entrance portion and is aligned along the rotation axis. Located in The image forming apparatus according to configuration 4, wherein the toner storage section has a detection area between the first exit section and the second entrance section in the direction along the rotation axis and through which the light passes. (Configuration 6) the first light guiding portion includes a first rectilinear portion extending along the rotation axis, the second light guiding portion includes a second rectilinear portion extending along the rotation axis, 6. The image forming apparatus according to configuration 5, wherein the first straight portion and the second straight portion extend so as to be aligned in a direction perpendicular to the axis of rotation. (Configuration 7) 7. The image forming apparatus according to configuration 6, wherein the closest portion is the second straight portion. (Configuration 8) 8. The image forming apparatus according to configuration 6 or 7, wherein the second straight portion is longer than the first straight portion. (Configuration 9) 9. The image forming apparatus according to any one of configurations 6 to 8, wherein the second straight portion is closer to the photosensitive drum than the first straight portion. (Configuration 10) A cartridge detachably mountable to a main body of an image forming apparatus, A developing roller; a frame having a toner storage portion; a first light guiding section attached to the frame that guides light for detecting an amount of toner contained in the toner containing section from an outside of the toner containing section to an inside of the toner containing section; a second light guiding portion attached to the frame for guiding the light having passed through the inside of the toner storage portion to the outside of the toner storage portion; a cover member that covers the first light guiding portion and the second light guiding portion; In a cartridge comprising: a portion of the second light guiding section that is closest to a passing area through which a laser beam for exposing a photosensitive drum of an exposure section provided in the device body passes is located closer to the passing area than any portion of the first light guiding section; A cartridge, wherein the cover member is configured not to cover the closest portion. (Configuration 11) 11. The cartridge of claim 10, wherein the closest portion is a portion extending along the scanning direction of the laser light. (Configuration 12) 11. The cartridge according to claim 10, wherein the closest portion is a portion extending along the axis of rotation of the developing roller. (Configuration 13) The first light guiding section is A first incident portion into which the light is incident from the outside of the frame body; a first exit portion that exits the light incident from the first entrance portion toward the inside of the toner storage portion; having The second light guiding section is a second incident portion into which the light having passed through the interior of the toner storage portion is incident; a second exit portion that emits the light incident from the second entrance portion toward an outside of the toner containing portion; having 13. The cartridge according to configuration 10 or 12, wherein the first entrance portion and the second exit portion are each provided at a first end of the frame body in a direction of a rotation axis of the developing roller. (Configuration 14) the first exit portion and the second entrance portion are disposed between the first end portion and a second end portion opposite to the first end portion of the frame body, the first exit portion being closer to the first end portion than the second entrance portion, and aligned along the rotation axis; The cartridge described in configuration 13, wherein the toner storage portion is sandwiched between the first emission portion and the second incidence portion in a direction along the rotation axis and has a detection area through which the light passes. (Configuration 15) the first light guiding portion includes a first rectilinear portion extending along the rotation axis, the second light guiding portion includes a second rectilinear portion extending along the rotation axis, 15. The cartridge according to configuration 14, wherein the first straight portion and the second straight portion extend so as to be aligned in a direction perpendicular to the axis of rotation. (Configuration 16) 16. The cartridge of claim 15, wherein the closest portion is the second straight portion. (Configuration 17) 17. The cartridge according to aspect 15 or 16, wherein the second straight portion is longer than the first straight portion. (Configuration 18) 18. The cartridge according to any one of configurations 15 to 17, wherein the second straight portion is closer to the photosensitive drum than the first straight portion. [Explanation of symbols]

[0112] 11...photosensitive drum, 15...developing unit, 16...developing roller, 151...developing chamber, 152...toner storage chamber, 153...toner receiving chamber, 450...toner remaining amount detection unit, 451...toner remaining amount detection board, 451a...LED, 451b...phototransistor, 501...light guide, 5011...first light guiding section, 5012...second light guiding section, 501b...first guide section, 501b1...first input side straight section, 501b2...second input side straight section, 501a...detection light input portion, 501c...emission surface inside the container chamber, 501e...second guide portion, 501e1...first output side straight portion, 501e2...second output side straight portion, 501d...light receiving surface inside the container chamber, 501f...detection light output portion, 501g...detection portion, 501h...passage portion, 502...light guide cover 502g...input straight cover portion, 502h...detection portion cover, 503...developing frame body A...printer main body, B...process cartridge

Claims

1. A photosensitive drum; an exposure section that exposes the photosensitive drum; a developing unit including a frame having a toner storage unit, a developing roller that develops an electrostatic image formed on the photosensitive drum by the laser light of the exposure unit using the toner stored in the toner storage unit, and a light transmitting unit attached to the frame; a light-emitting section; and a light-receiving section that receives light emitted from the light-emitting section, the light-receiving section passing through the inside of the toner storage section and emerging outside the toner storage section, and that transmits a detection signal according to the amount of light received by the light-receiving section; Equipped with The light transmitting portion is a first light guiding portion that guides the light emitted by the light emitting portion into the inside of the toner containing portion; a second light guiding portion that guides the light that has passed through the interior of the toner storage portion to the light receiving portion; having An image forming apparatus having a cover member for covering the first light guiding section and the second light guiding section, a portion of the second light guiding section that is closest to a passage region through which the laser light passes is located closer to the passage region than any portion of the first light guiding section; The image forming apparatus according to claim 1, wherein the cover member is configured so as not to cover the closest portion.

2. 2. The image forming apparatus according to claim 1, wherein the closest portion is a portion extending along a scanning direction of the laser light.

3. 2. The image forming apparatus according to claim 1, wherein the closest portion is a portion extending along a rotation axis of the developing roller.

4. The first light guiding portion is a first incident portion into which the light emitted by the light emitting portion is incident; a first exit portion that outputs the light incident from the first entrance portion toward the inside of the toner storage portion; having The second light guiding portion is a second incident portion into which the light having passed through the interior of the toner storage portion is incident; a second exit portion that outputs the light incident from the second entrance portion toward the light receiving portion; having 2 . The image forming apparatus according to claim 1 , wherein the first entrance portion and the second exit portion are provided at a first end of the frame in a direction of a rotation axis of the developing roller.

5. the first exit portion and the second entrance portion are disposed between the first end portion of the frame and a second end portion opposite to the first end portion in the direction of the rotation axis, such that the first exit portion is located closer to the first end portion than the second entrance portion, and are aligned along the rotation axis; 5 . The image forming apparatus according to claim 4 , wherein the toner storage section has a detection area, through which the light passes, located between the first emission section and the second incidence section in the direction along the rotation axis.

6. the first light guiding portion includes a first straight portion extending along the rotation axis, the second light guiding portion includes a second rectilinear portion extending along the rotation axis, 6. The image forming apparatus according to claim 5, wherein the first straight portion and the second straight portion extend so as to be aligned in a direction perpendicular to the axis of rotation.

7. The image forming apparatus according to claim 6 , wherein the closest portion is the second straight portion.

8. 8. The image forming apparatus according to claim 7, wherein the second straight portion is longer than the first straight portion.

9. 8. The image forming apparatus according to claim 7, wherein the second straight portion is closer to the photosensitive drum than the first straight portion.

10. A cartridge detachably mountable to a main body of an image forming apparatus, A developing roller; a frame having a toner storage portion; a first light guiding portion attached to the frame for guiding light for detecting an amount of toner contained in the toner containing portion from an outside of the toner containing portion to an inside of the toner containing portion; a second light guiding portion attached to the frame for guiding the light having passed through the inside of the toner storage portion to the outside of the toner storage portion; a cover member that covers the first light guiding portion and the second light guiding portion; In a cartridge comprising: a portion of the second light guiding section that is closest to a passing area through which a laser beam for exposing a photosensitive drum of an exposure section provided in the apparatus body passes is located closer to the passing area than any portion of the first light guiding section; A cartridge, wherein the cover member is configured not to cover the closest portion.

11. 11. A cartridge according to claim 10, wherein the closest portion is a portion extending along a scanning direction of the laser light.

12. 11. A cartridge according to claim 10, wherein said closest portion is a portion extending along the rotation axis of said developing roller.

13. The first light guiding portion is A first incident portion into which the light is incident from the outside of the frame body; a first exit portion that outputs the light incident from the first entrance portion toward the inside of the toner storage portion; having The second light guiding portion is a second incident portion into which the light having passed through the interior of the toner storage portion is incident; a second exit portion that outputs the light incident from the second entrance portion toward an outside of the toner storage portion; having 11. A cartridge according to claim 10, wherein the first entrance portion and the second exit portion are each provided at a first end of the frame in a direction of the rotation axis of the developing roller.

14. the first exit portion and the second entrance portion are disposed between the first end portion and a second end portion opposite to the first end portion of the frame body, the first exit portion being closer to the first end portion than the second entrance portion, and aligned along the rotation axis; The cartridge according to claim 13 , wherein the toner storage portion is sandwiched between the first emission portion and the second incidence portion in the direction along the rotation axis, and has a detection region through which the light passes.

15. the first light guiding portion includes a first straight portion extending along the rotation axis, the second light guiding portion includes a second rectilinear portion extending along the rotation axis, 15. A cartridge according to claim 14, wherein the first straight portion and the second straight portion extend so as to be aligned in a direction perpendicular to the rotation axis.

16. A cartridge according to claim 15, wherein the closest portion is the second straight portion.

17. 17. A cartridge according to claim 16, wherein the second straight portion is longer than the first straight portion.

18. 17. A cartridge according to claim 16, wherein the second straight portion is closer to the photosensitive drum than the first straight portion.

Images