Drum unit

Abstract

This technology provides a way to recognize that an Oldham coupling is not connected to the cleaning roller. [Solution] Either the drum frame 30 or the bearing 80 has a hook 83. The other drum frame 30 or bearing 80 has a corner 34 into which the hook 83 can engage. When the Oldham coupling 70 is connected to the cleaning roller 40, the hook 83 engages with the corner 34. When the Oldham coupling 70 is not connected to the cleaning roller 40, the hook 83 does not engage with the corner 34.

Description

Technical Field

[0001] The present disclosure relates to a drum unit.

Background Art

[0002] Conventionally, an electrophotographic image forming apparatus is known. The image forming apparatus has a drum unit. The drum unit includes a photosensitive drum and a cleaning roller that cleans the outer peripheral surface of the photosensitive drum. A conventional drum unit including a photosensitive drum and a cleaning roller is described in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The drum unit of Patent Document 1 has an Oldham coupling that connects a cleaning roller and a gear. The Oldham coupling transmits rotation from the gear to the cleaning roller while allowing axial misalignment between the cleaning roller and the gear.

[0005] The Oldham coupling is disposed between the gear and the cleaning roller. Therefore, it is difficult to visually confirm from the outside whether the Oldham coupling is connected to the cleaning roller. If the Oldham coupling is not connected to the cleaning roller, rotation is not transmitted from the Oldham coupling to the cleaning roller.

[0006] An object of the present disclosure is to provide a technique that can recognize that the Oldham coupling is not connected to the cleaning roller.

Means for Solving the Problems

[0007] The first disclosure of the present application comprises a drum frame, a photoreceptor drum rotatable about a drum shaft extending in a first direction, a cleaning roller rotatable about a cleaning shaft extending in the first direction, the cleaning roller in contact with the outer surface of the photoreceptor drum, a cleaning gear rotating with the cleaning roller, the cleaning gear located at one end of the drum frame in the first direction, an Oldham coupling connecting one end of the cleaning roller in the first direction to the cleaning gear, and a bearing rotatably supporting the cleaning gear, wherein either the drum frame or the bearing has a hook, and the other of the drum frame or the bearing has a corner into which the hook can engage, and when the Oldham coupling is connected to one end of the cleaning roller, the hook engages with the corner, and when the Oldham coupling is not connected to one end of the cleaning roller, the hook does not engage with the corner.

[0008] The second disclosure of this application is a drum unit of the first disclosure, characterized in that the bearing has the hook and the drum frame has the angle.

[0009] A third disclosure of the present application is a drum unit of the second disclosure, wherein the cleaning roller has a shaft extending in the first direction, and the Oldham coupling is connected to one end of the shaft in the first direction.

[0010] A fourth disclosure of the present application is a drum unit of the third disclosure, wherein the Oldham coupling has a first groove extending in a direction intersecting the cleaning shaft, and the shaft has a first slider inserted into the first groove.

[0011] A fifth disclosure of the present application is a drum unit of the fourth disclosure, wherein the cleaning gear has a second groove that intersects the cleaning shaft and extends in a direction different from the first groove, and the Oldham coupling has a second slider that is inserted into the second groove.

[0012] The sixth disclosure of this application is a drum unit according to any one of the second to fifth disclosures, comprising a drum gear that rotates together with the photoreceptor drum and further comprises a drum gear that meshes with the cleaning gear, wherein the bearing has a cleaning bearing portion that rotatably supports the cleaning gear and a drum bearing portion that rotatably supports the drum gear.

[0013] The seventh disclosure of this application is the drum unit of the sixth disclosure, characterized in that the hook is located closer to the cleaning bearing portion than to the drum bearing portion.

[0014] The eighth disclosure of this application is a drum unit of the seventh disclosure, characterized in that the photoreceptor drum and the cleaning roller are aligned in a second direction intersecting the first direction, and the hook extends from one end of the bearing in the second direction.

[0015] The ninth disclosure of this application is a drum unit of the eighth disclosure, wherein the hook has an arm extending from one end of the bearing in the second direction and a claw projecting from the arm in a direction intersecting the first direction, the claw engaging with the corner.

[0016] The tenth disclosure of this application is the drum unit of the ninth disclosure, wherein the claw has an inclined surface that is inclined with respect to the first direction, and in the process of mounting the bearing to the drum frame, the inclined surface comes into contact with the drum frame, causing the arm to bend, and the claw engages with the corner, thereby eliminating the bending of the arm.

[0017] The 11th disclosure of the present application is a drum unit of any one of the 1st to 10th disclosures, including a first photosensitive drum which is the photosensitive drum, a second photosensitive drum different from the first photosensitive drum, a first cleaning roller which is the cleaning roller and contacts the outer peripheral surface of the first photosensitive drum, and a second cleaning roller different from the first cleaning roller and contacting the outer peripheral surface of the second photosensitive drum.

Effect of the Invention

[0018] According to the 1st to 11th disclosures, when the Oldham coupling is not connected to the cleaning roller, the hook does not engage with the corner. Thereby, it can be recognized that the Oldham coupling is not connected to the cleaning roller.

[0019] Also, according to the 7th disclosure, the displacement of the hook with respect to the Oldham coupling can be suppressed.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram of an image forming apparatus. [Figure 2] It is a perspective view of a drum unit. [Figure 3] It is a partial cross-sectional view of a drum unit. [Figure 4] It is a side view of a connection frame, a photosensitive drum, and a cleaning roller. [Figure 5] It is an exploded perspective view near the end of a photosensitive drum and a cleaning roller. [Figure 6] It is a perspective view of a bearing. [Figure 7] It is a view showing a state where a bearing is normally attached to a drum frame. [Figure 8] It is a flowchart showing the procedure when assembling a cleaning roller, an Oldham coupling, a cleaning gear, and a bearing in the manufacturing process of a drum unit. [Figure 9] This is a diagram showing that the bearing is not properly attached to the drum frame.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0022] In the following description, the direction in which the drum shaft of the photosensitive drum extends is referred to as the "first direction". Also, the direction in which the photosensitive drum and the cleaning roller are arranged side by side is referred to as the "second direction". The first direction and the second direction intersect each other. For example, the first direction and the second direction are perpendicular to each other.

[0023] <1. Configuration of the Image Forming Apparatus> FIG. 1 is a schematic diagram of an image forming apparatus 100. This image forming apparatus 100 is an electrophotographic printer. Specifically, the image forming apparatus 100 is a laser printer or an LED printer. As shown in FIG. 1, the image forming apparatus 100 includes a main body frame 101, a drum unit 2, and four developing cartridges 1.

[0024] The four developing cartridges 1 can be attached to the drum unit 2. Also, the drum unit 2 with the four developing cartridges 1 attached can be attached to the main body frame 101. The drum unit 2 is attached to the main body frame 101 by moving in the second direction with respect to the main body frame 101.

[0025] The developing cartridge 1 houses toner. Also, the developing cartridge 1 has a developing roller 10. The drum unit 2 has four photosensitive drums 20. When the developing cartridge 1 is attached to the drum unit 2, the developing roller 10 and the photosensitive drum 20 come into contact.

[0026] The toner in the developing cartridge 1 is supplied to the photoreceptor drum 20 via the developing roller 10. The image forming apparatus 100 prints an image on the printing paper by transferring the toner from the photoreceptor drum 20 to the printing paper.

[0027] <2. Drum Unit Configuration> Figure 2 is a perspective view of the drum unit 2. The drum unit 2 has four photosensitive drums 20 and a drum frame 30.

[0028] The photoreceptor drum 20 is a drum that can rotate about a drum axis A1 extending in a first direction. Four photoreceptor drums 20 are arranged spaced apart from each other in a second direction. The photoreceptor drum 20 has a cylindrical outer surface centered on the drum axis A1. The outer surface of the photoreceptor drum 20 is covered with a photosensitive material.

[0029] The drum frame 30 supports four photoreceptor drums 20 so that they can rotate around the drum axis A1. The drum frame 30 has a first side frame 31, a second side frame 32, and four connecting frames 33.

[0030] The first side frame 31 is located at one end of the drum frame 30 in a first direction. The first side frame 31 extends in a second direction. The first side frame 31 may be composed of multiple plates. For example, the first side frame 31 may be composed of a metal plate and a resin plate fixed to the metal plate.

[0031] The second side frame 32 is located at the other end of the drum frame 30 in the first direction. The second side frame 32 extends in the second direction. The second side frame 32 may be composed of multiple plates. For example, the second side frame 32 may be composed of a metal plate and a resin plate fixed to the metal plate.

[0032] The photoreceptor drum 20 is positioned between the first side frame 31 and the second side frame 32 in a first direction. One end of the photoreceptor drum 20 in the first direction is rotatably supported with respect to the first side frame 31. The other end of the photoreceptor drum 20 in the first direction is rotatably supported with respect to the second side frame 32.

[0033] The connecting frame 33 is a frame that connects the first side frame 31 and the second side frame 32. The connecting frame 33 is made of resin. The four connecting frames 33 are arranged spaced apart from each other in the second direction. Each connecting frame 33 extends in the first direction between the first side frame 31 and the second side frame 32. One end of the connecting frame 33 in the first direction is connected to the first side frame 31. The other end of the connecting frame 33 in the first direction is connected to the second side frame 32.

[0034] The four developing cartridges 1 are mounted on the drum frame 30. When the developing cartridges 1 are mounted on the drum frame 30, the developing cartridges 1 are positioned between the first side frame 31 and the second side frame 32 in the first direction. Also, when the developing cartridges 1 are positioned on the drum frame 30, the outer surface of the developing roller 10 is in contact with the outer surface of the photoreceptor drum 20. This allows the toner carried on the outer surface of the developing roller 10 to be supplied to the photoreceptor drum 20.

[0035] Figure 3 is a partial cross-sectional view of the drum unit 2. Figure 3 shows a cross-section perpendicular to the first direction. As shown in Figure 3, the drum unit 2 includes cleaning rollers 40. The cleaning rollers 40 are rollers for cleaning the outer surface of the photoreceptor drum 20. One cleaning roller 40 is provided for each photoreceptor drum 20. That is, the drum unit 2 has four cleaning rollers 40.

[0036] The cleaning roller 40 is located between the first side frame 31 and the second side frame 32 in the first direction. The photoreceptor drum 20 and the cleaning roller 40 are aligned in the second direction. The cleaning roller 40 is rotatable with respect to the cleaning axis A2 extending in the first direction.

[0037] The cleaning roller 40 has a shaft 41 and a roller body 42. The shaft 41 is a cylindrical member extending along the cleaning axis A2. The shaft 41 is made of a conductive material. Specifically, the shaft 41 is made of metal or a conductive resin. The roller body 42 is a cylindrical member centered on the cleaning axis A2. The roller body 42 is made of elastically deformable rubber or sponge. The roller body 42 is fixed to the shaft 41.

[0038] The shaft 41 extends in a first direction, passing through the roller body 42. One end of the shaft 41 in the first direction is rotatably supported by the first side frame 31. The other end of the shaft 41 in the first direction is rotatably supported by the second side frame 32. The outer circumferential surface of the roller body 42 is in contact with the outer circumferential surface of the photosensitive drum 20.

[0039] The drum unit 2 is equipped with electrodes (not shown). The electrodes contact one end or the other end of the shaft 41 in a first direction. When the drum unit 2 is mounted on the main frame 101 of the image forming apparatus 100, the image forming apparatus 100 supplies voltage to the shaft 41 via the electrodes. The electrostatic force of this voltage attracts the developer and paper dust from the outer surface of the photoreceptor drum 20 to the outer surface of the cleaning roller 40. This cleans the outer surface of the photoreceptor drum 20.

[0040] Furthermore, the outer surface of the cleaning roller 40 rotates at a different rotational speed than the outer surface of the photoreceptor drum 20. Therefore, the outer surface of the cleaning roller 40 and the outer surface of the photoreceptor drum 20 rub against each other. This results in better cleaning of the outer surface of the photoreceptor drum 20.

[0041] Figure 4 is a side view of the connecting frame 33, the photoreceptor drum 20, and the cleaning roller 40. Figure 5 is an exploded perspective view of the area near the ends of the photoreceptor drum 20 and the cleaning roller 40. As shown in Figures 4 and 5, the drum unit 2 comprises a drum gear 50, a cleaning gear 60, an Oldham coupling 70, and a bearing 80.

[0042] A drum gear 50 is provided for each photoreceptor drum 20. That is, the drum unit 2 comprises four drum gears 50. The drum gear 50 is located at one end of the photoreceptor drum 20 in the first direction. Specifically, the drum gear 50 is fixed to one end of the photoreceptor drum 20 in the first direction. Therefore, the drum gear 50 is rotatable together with the photoreceptor drum 20 around the drum axis A1. The drum gear 50 has multiple teeth on its outer circumferential surface.

[0043] The drum gear 50 has a drum coupling 51. The drum coupling 51 is exposed to the outside from the first side frame 31. When the drum unit 2 is mounted on the main frame 101 of the image forming apparatus 100, the drive shaft of the image forming apparatus 100 is connected to the drum coupling 51. Rotation is then transmitted from the drive shaft to the drum coupling 51. As a result, the drum gear 50 rotates around the drum axis A1. The photoreceptor drum 20 also rotates around the drum axis A1 together with the drum gear 50.

[0044] In this embodiment, the drum gear 50 and the drum coupling 51 are formed from a single component. However, the drum gear 50 and the drum coupling 51 may be separate components. In that case, it is sufficient that the drum gear 50 and the drum coupling 51 are fixed so that they cannot rotate relative to each other.

[0045] A cleaning gear 60 is provided for each cleaning roller 40. That is, the drum unit 2 has four cleaning gears 60. The cleaning gear 60 is located at one end of the drum frame 30 in the first direction. One end of the cleaning gear 60 in the first direction is connected to a bearing 80. The other end of the cleaning gear 60 in the first direction is connected to one end of the shaft 41 in the first direction via an Oldham coupling 70. Thus, the cleaning gear 60 is rotatable together with the cleaning roller 40 around the cleaning shaft A2.

[0046] The cleaning gear 60 has multiple teeth on its outer surface. The cleaning gear 60 meshes with the drum gear 50. Therefore, when the drum gear 50 rotates, the cleaning gear 60 rotates around the cleaning shaft A2. The cleaning roller 40 also rotates around the cleaning shaft A2 together with the cleaning gear 60.

[0047] An Oldham coupling 70 is provided for each cleaning roller 40. That is, the drum unit 2 has four Oldham couplings 70. The Oldham coupling 70 is a coupling that connects the shaft 41 of the cleaning roller 40 to the cleaning gear 60. One end of the Oldham coupling 70 in the first direction is connected to the cleaning gear 60. The other end of the Oldham coupling 70 in the first direction is connected to the shaft 41.

[0048] As shown in Figure 5, the Oldham coupling 70 has a first groove 71. The first groove 71 is located at the other end of the Oldham coupling 70 in a first direction. The first groove 71 is recessed in a first direction from the other end to the one end of the Oldham coupling 70 in a first direction. The first groove 71 also extends in a first sliding direction D1 that intersects the cleaning axis A2.

[0049] The shaft 41 has a first slider 43. The first slider 43 is located at one end of the shaft 41 in a first direction. The first slider 43 protrudes in a first direction from one end of the shaft 41 in a first direction toward the Oldham coupling 70. The first slider 43 also extends in a first sliding direction D1.

[0050] The first slider 43 is inserted into the first groove 71. The length of the first groove 71 in the first sliding direction D1 is longer than the length of the first slider 43 in the first sliding direction D1. Therefore, while inserted into the first groove 71, the first slider 43 can move relative to the first groove 71 in the first sliding direction D1. This allows rotation to be transmitted between the Oldham coupling 70 and the cleaning roller 40 while allowing misalignment in the first sliding direction D1.

[0051] Furthermore, as shown in Figure 5, the Oldham coupling 70 has a second slider 72. The second slider 72 is located at one end of the Oldham coupling 70 in the first direction. The second slider 72 protrudes in the first direction from one end of the Oldham coupling 70 toward the cleaning gear 60. The second slider 72 also extends in a second sliding direction D2 which intersects the cleaning axis A2 and is different from the first sliding direction D1. The first sliding direction D1 and the second sliding direction D2 are preferably orthogonal.

[0052] The cleaning gear 60 has a second groove 61. The second groove 61 is located at the other end of the cleaning gear 60 in the first direction. The second groove 61 is recessed in the first direction from the other end to the one end of the cleaning gear 60 in the first direction. The second groove 61 also extends in the second sliding direction D2.

[0053] The second slider 72 is inserted into the second groove 61. The length of the second groove 61 in the second sliding direction D2 is longer than the length of the second slider 72 in the second sliding direction D2. Therefore, while inserted into the second groove 61, the second slider 72 can move relative to the second groove 61 in the second sliding direction D2. This allows rotation to be transmitted between the cleaning gear 60 and the Oldham coupling 70 while allowing misalignment in the second sliding direction D2.

[0054] In this way, the Oldham coupling 70 transmits rotation from the cleaning gear 60 to the shaft 41 while allowing misalignment of the shaft 41 in the first sliding direction D1 and the second sliding direction D2 relative to the cleaning gear 60. That is, the Oldham coupling 70 transmits rotation from the cleaning gear 60 to the shaft 41 while allowing axial misalignment between the cleaning gear 60 and the shaft 41. This stabilizes the contact state of the cleaning roller 40 with respect to the photoreceptor drum 20. As a result, the outer surface of the photoreceptor drum 20 can be cleaned well by the cleaning roller 40.

[0055] The bearing 80 is a member that rotatably supports the drum gear 50 and the cleaning gear 60. The bearing 80 is fixed to the first side frame 31. Figure 6 is a perspective view of the bearing 80. As shown in Figures 5 and 6, the bearing 80 has a drum bearing section 81 and a cleaning bearing section 82. The drum bearing section 81 rotatably supports the drum gear 50 with respect to the drum shaft A1. The cleaning bearing section 82 rotatably supports the cleaning gear 60 with respect to the cleaning shaft A2.

[0056] The drum bearing portion 81 is a hole that penetrates the bearing 80 in a first direction. The drum bearing portion 81 has a cylindrical inner circumferential surface centered on the drum shaft A1. The cleaning bearing portion 82 is a projection that extends in a first direction from the bearing 80 toward the cleaning gear 60. The cleaning bearing portion 82 has a cylindrical outer circumferential surface centered on the cleaning shaft A2.

[0057] The drum coupling 51 is inserted into the drum bearing portion 81. This allows the drum gear 50 to rotatably support the bearing 80 with respect to the drum shaft A1. The cleaning gear 60 has a hole 62. The hole 62 is located at one end of the cleaning gear 60 in a first direction. The hole 62 extends in a first direction from one end to the other end of the cleaning gear 60 in a first direction. The cleaning bearing portion 82 is inserted into the hole 62 of the cleaning gear 60. This allows the cleaning gear 60 to rotatably support the bearing 80 with respect to the cleaning shaft A2.

[0058] The bearing 80 maintains a constant distance between the drum gear 50 and the cleaning gear 60 in the second direction. As a result, rotation is transmitted accurately from the drum gear 50 to the cleaning gear 60.

[0059] As shown in Figure 6, the bearing 80 has a hook 83. The hook 83 is located at one end of the bearing 80 in the second direction. More specifically, the hook 83 extends from one end of the bearing 80 in the second direction toward the cleaning roller 40 in the first direction. The drum bearing portion 81, the cleaning bearing portion 82, and the hook 83 are aligned in the second direction. The hook 83 is located closer to the cleaning bearing portion 82 than to the drum bearing portion 81.

[0060] The hook 83 has an arm 831 and a claw 832. The arm 831 extends from one end of the bearing 80 in a second direction away from the cleaning bearing portion 82 in a second direction, and also extends towards the cleaning roller 40 in a first direction. The claw 832 protrudes from the tip of the arm 831 in a second direction. However, the direction in which the claw 832 protrudes is not limited to the second direction, but may be any direction intersecting the first direction. The claw 832 has an inclined surface 833. The inclined surface 833 is inclined with respect to the first direction.

[0061] Figure 7 shows the bearing 80 properly mounted on the drum frame 30. In Figure 7, the area around the bearing 80 is viewed in directions perpendicular to the first and second directions. As shown in Figure 7, the drum frame 30 has a corner 34. The corner 34 is formed, for example, by a step, a through hole, or a recess. The corner 34 has a surface that intersects in the first direction. The hook 83 engages with the corner 34. More specifically, the claw 832 of the hook 83 engages with the corner 34. The claw 832 and the corner 34 face each other in the first direction. This prevents the bearing 80 from coming off the drum frame 30 in the first direction.

[0062] Figure 8 is a flowchart showing the procedure for assembling the cleaning roller 40, Oldham coupling 70, cleaning gear 60, and bearing 80 in the manufacturing process of the drum unit 2. In the example in Figure 7, first, the cleaning gear 60 and Oldham coupling 70 are attached to the bearing 80 (step S1). Next, the bearing 80 with the cleaning gear 60 and Oldham coupling 70 attached is attached to the drum frame 30 (step S2).

[0063] In step S2, the bearing 80 is moved in a first direction, bringing it closer to the cleaning roller 40. Then, the Oldham coupling 70 is connected to one end of the cleaning roller 40 in the first direction. At this time, the inclined surface 833 of the hook 83 contacts a portion of the drum frame 30, causing the arm 831 of the hook 83 to bend in a second direction. When the first slider 43 of the cleaning roller 40 is properly inserted into the first groove 71 of the Oldham coupling 70, the claw 832 reaches the corner 34 of the drum frame 30 in the first direction. As a result, the bending of the arm 831 is eliminated, and the hook 83 of the bearing 80 engages with the corner 34, as shown in Figure 7.

[0064] Figure 9 shows a situation where the bearing 80 is not properly mounted on the drum frame 30. In Figure 9, the area around the bearing 80 is viewed in directions perpendicular to the first and second directions. In the example in Figure 9, the first slider 43 of the cleaning roller 40 is not properly inserted into the first groove 71 of the Oldham coupling 70. In this case, the claw 832 of the hook 83 of the bearing 80 does not reach the corner 34 of the drum frame 30 in the first direction. Therefore, as shown in Figure 9, the hook 83 of the bearing 80 does not engage with the corner 34.

[0065] During step S2, it is not possible to directly visually confirm whether the first slider 43 of the cleaning roller 40 is properly inserted into the first groove 71 of the Oldham coupling 70. If the first slider 43 of the cleaning roller 40 is not properly inserted into the first groove 71 of the Oldham coupling 70, rotation will not be transmitted from the cleaning gear 60 to the cleaning roller 40. However, in the structure of this embodiment, if the Oldham coupling 70 is not properly connected to the cleaning roller 40, the hook 83 will not engage with the corner 34. This makes it possible to recognize that the Oldham coupling 70 is not connected to the cleaning roller 40.

[0066] In particular, in this embodiment, the hook 83 is located closer to the cleaning bearing portion 82 than to the drum bearing portion 81. Therefore, the displacement of the hook 83 relative to the Oldham coupling 70 can be suppressed more effectively than when the hook 83 is located closer to the drum bearing portion 81. Consequently, when the Oldham coupling 70 is not connected to the cleaning roller 40, the hook 83 is less likely to engage with the corner 34.

[0067] <3. Variant> Although one embodiment has been described above, this disclosure is not limited to the above embodiment.

[0068] In the above embodiment, the bearing 80 had a hook 83, and the drum frame 30 had a corner 34 that could engage with the hook 83. However, the drum frame 30 may have a hook, and the bearing 80 may have a corner that can engage with the hook. That is, either the drum frame 30 or the bearing 80 may have a hook, and the other of the drum frame 30 or the bearing 80 may have a corner that can engage with the hook.

[0069] In the above embodiment, the drum bearing portion 81 was a circular hole penetrating the bearing 80 in the first direction. However, the drum bearing portion 81 may be a circular recess or a circular projection extending in the first direction. The drum bearing portion 81 only needs to be shaped to fit with the drum gear 50 and rotatably support the drum gear 50.

[0070] In the above embodiment, the cleaning bearing portion 82 was a circular projection extending in the first direction. However, the cleaning bearing portion 82 may be a circular recess or a circular hole penetrating the bearing 80 in the first direction. The cleaning bearing portion 82 only needs to be shaped to fit with the cleaning gear 60 and rotatably support the cleaning gear 60.

[0071] In the above embodiment, the connection between the Oldham coupling 70 and the shaft 41 was achieved by a first groove 71 provided in the Oldham coupling 70 and a first slider 43 provided in the shaft 41. However, the connection between the Oldham coupling 70 and the shaft 41 may also be achieved by a slider provided in the Oldham coupling 70 and a groove provided in the shaft 41.

[0072] In the above embodiment, the connection between the cleaning gear 60 and the Oldham coupling 70 was achieved by a second groove 61 provided in the cleaning gear 60 and a second slider 72 provided in the Oldham coupling 70. However, the connection between the cleaning gear 60 and the Oldham coupling 70 may also be achieved by a slider provided in the cleaning gear 60 and a groove provided in the Oldham coupling 70.

[0073] Furthermore, in the above embodiment, the drum unit 2 comprised a plurality of photoreceptor drums 20 and a plurality of cleaning rollers 40. That is, the drum unit 2 included a first photoreceptor drum and a second photoreceptor drum separate from the first photoreceptor drum. The drum unit 2 also included a first cleaning roller that contacts the outer circumferential surface of the first photoreceptor drum, and a second cleaning roller separate from the first cleaning roller that contacts the outer circumferential surface of the second photoreceptor drum.

[0074] However, the number of photoreceptor drums 20 and cleaning rollers 40 in the drum unit 2 is not limited to the above embodiment. The number of photoreceptor drums 20 in the drum unit 2 may be 1 to 3, or 5 or more. Similarly, the number of cleaning rollers 40 in the drum unit 2 may be 1 to 3, or 5 or more. For example, the drum unit 2 may have one photoreceptor drum 20 and one cleaning roller 40 that contacts the outer surface of the photoreceptor drum 20.

[0075] Furthermore, the detailed shape of the drum unit may differ from the shape shown in the figures of this application. In addition, elements that appear in the above embodiments and modifications may be appropriately selected and omitted to the extent that no inconsistencies arise. [Explanation of Symbols]

[0076] 1: Developing cartridge 2: Drum Unit 10: Developing roller 20: Photoconductor drum 30: Drum frame 34: corner 40: Cleaning roller 41: Shaft 42: Roller body 43: First slider 50: Drum Gear 60: Cleaning Gear 61: 2nd groove 70: Oldham Coupling 71: 1st groove 72: Second slider 80: Bearing 81: Drum bearing section 82: Cleaning bearing section 83: Hook 100: Image forming apparatus 831: Arm 832: Nail 833: Inclined surface A1: Drum shaft A2: Cleaning shaft

Claims

1. Drum frame and A photoreceptor drum that is rotatable with respect to a drum shaft extending in a first direction, A cleaning roller rotatable with respect to a cleaning shaft extending in the first direction, the cleaning roller in contact with the outer surface of the photoreceptor drum, A cleaning gear that rotates together with the cleaning roller, the cleaning gear located at one end of the drum frame in the first direction, An Oldham coupling connecting one end of the cleaning roller and the cleaning gear in the first direction, A bearing that rotatably supports the cleaning gear, Equipped with, Either the drum frame or the bearing has a hook, The other, the drum frame and the bearing, has an angle into which the hook can engage. When the Oldham coupling is connected to one end of the cleaning roller, the hook engages with the corner, A drum unit characterized in that, if the Oldham coupling is not connected to one end of the cleaning roller, the hook does not engage with the corner.

2. A drum unit according to claim 1, The bearing has the hook, A drum unit characterized in that the drum frame has the corners.

3. The drum unit according to claim 2, The cleaning roller has a shaft extending in the first direction, The Oldham coupling is connected to one end of the shaft in the first direction, characterized in that it is a drum unit.

4. The drum unit according to claim 3, The Oldham coupling described above is A first groove extending in a direction intersecting the cleaning shaft. It has, The aforementioned shaft is The first slider is inserted into the first groove. A drum unit characterized by having the following features.

5. The drum unit according to claim 4, The cleaning gear is A second groove intersects the cleaning shaft and extends in a direction different from that of the first groove. It has, The Oldham coupling described above is The second slider is inserted into the second groove. A drum unit characterized by having the following features.

6. A drum unit according to any one of claims 2 to 5, A drum gear that rotates together with the photoreceptor drum, and which meshes with the cleaning gear. Furthermore, The aforementioned bearing is A cleaning bearing portion that rotatably supports the cleaning gear, A drum bearing portion that rotatably supports the drum gear, A drum unit characterized by having the following features.

7. The drum unit according to claim 6, The drum unit is characterized in that the hook is located closer to the cleaning bearing portion than to the drum bearing portion.

8. The drum unit according to claim 7, The photoreceptor drum and the cleaning roller are arranged in a second direction that intersects the first direction, The drum unit is characterized in that the hook extends from one end of the bearing in the second direction.

9. A drum unit according to claim 8, The aforementioned hook is An arm extending from one end of the bearing in the second direction, A claw protruding from the arm in a direction intersecting the first direction, It has, A drum unit characterized in that the claw engages with the corner.

10. The drum unit according to claim 9, The claw has an inclined surface that is inclined with respect to the first direction, A drum unit in which, during the process of attaching the bearing to the drum frame, the inclined surface comes into contact with the drum frame, causing the arm to bend, and the claw engages with the corner, thereby eliminating the bending of the arm.

11. A drum unit according to any one of claims 1 to 5, The first photosensitive drum, which is the aforementioned photosensitive drum, A second photoreceptor drum, separate from the first photoreceptor drum, The first cleaning roller, which is the cleaning roller, is a first cleaning roller that contacts the outer surface of the first photoreceptor drum, A second cleaning roller, separate from the first cleaning roller, which contacts the outer surface of the second photoreceptor drum, A drum unit characterized by having the following features.

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