Process cartridge

Abstract

To provide a process cartridge in which a pressing member can press a developing cartridge toward a photoconductor drum at a position close to the photoconductor drum.SOLUTION: A process cartridge 5 comprises a drum cartridge 6, and a developing cartridge 7 that is removably attached to the drum cartridge 6. The drum cartridge 6 includes a photoconductor drum 61, and a pressing member 150A that, in a state where the developing cartridge 7 is attached to the drum cartridge 6, presses the developing cartridge 7 toward the photoconductor drum 61. The developing cartridge 7 includes a developing roller 71, a supply roller 72 that has a supply roller shaft 72A, and a developing frame 75. The developing frame 75 has a side wall 210A, and a pressing wall 220A that projects from the side wall 210A and surrounds one end of the supply roller shaft 72A. In a state where the developing cartridge 7 is attached to the drum cartridge 6, the pressing wall 220A is pressed by the pressing member 150A.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a process cartridge. [Background technology]

[0002] Conventionally, a process cartridge including a drum cartridge and a developing cartridge detachably attached to the drum cartridge is known (Patent Document 1). The drum cartridge includes a photosensitive drum, a pressing member, and a drum frame that supports the photosensitive drum and the pressing member. The pressing member presses the developing cartridge toward the photosensitive drum when the developing cartridge is attached to the drum cartridge. The developing cartridge includes a developing roller and a developing frame that supports the developing roller. In this technology, when the developing cartridge is attached to the drum cartridge, a wall of the developing frame located at the end farther from the photosensitive drum is pressed by the pressing member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-016480 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the drum frame is deformed by the reaction force of the pressing member, which the pressing member receives from the developer cartridge, a loss of pressing force occurs. In a configuration in which the pressing member presses the end of the developer frame farther from the photosensitive drum, the loss of pressing force due to the deformation of the drum frame becomes large.

[0005] Therefore, it is desirable to be able to press the developing cartridge toward the photosensitive drum by a pressing member at a position close to the photosensitive drum. [Means for solving the problem]

[0006] The process cartridge includes a drum cartridge and a developing cartridge that is detachably attached to the drum cartridge. The drum cartridge includes a photosensitive drum and a pressing member. The photosensitive drum is rotatable about a drum axis extending in a first direction. The pressing member presses the developing cartridge toward the photosensitive drum when the developing cartridge is attached to the drum cartridge. The developing cartridge includes a developing roller, a supply roller, and a developing frame. The developing roller is rotatable about a developing roller axis that extends in a first direction. The supply roller is rotatable about a supply roller axis extending in a first direction. The supply roller has a supply roller shaft extending in the first direction. The developer frame has a side wall and a pressing wall. The side wall is located at one end of the developing frame in the first direction. The pressing wall protrudes from the side wall in a first direction and surrounds one end of the supply roller shaft in the first direction. The pressing wall is pressed by a pressing member when the developing cartridge is attached to the drum cartridge.

[0007] The pressing wall surrounding one end of the supply roller shaft in the first direction is pressed by the pressing member, so that the developing cartridge can be pressed toward the photosensitive drum at a position close to the photosensitive drum by the pressing member.

[0008] The pressing wall may have a first wall, a second wall, and a third wall. The second wall faces the first wall in a second direction perpendicular to the first direction. The third wall connects one end of the first wall and one end of the second wall. One end of the supply roller shaft in the first direction is located between the first wall and the second wall. The third wall is pressed by a pressing member when the developing cartridge is attached to the drum cartridge.

[0009] The dimension of the third wall in the first direction may be greater than the dimension of the first wall in the first direction and greater than the dimension of the second wall in the first direction.

[0010] Since the dimension in the first direction of the third wall pressed by the pressing member is large, the developing cartridge can be stably pressed toward the photosensitive drum when the third wall is pressed by the pressing member.

[0011] The developer frame can accommodate toner, and the developer cartridge may further include a seal. A seal is located between the feed roller shaft and the pressure wall.

[0012] By providing a seal positioned between the supply roller shaft and the pressing wall, it is possible to prevent toner from leaking from between the supply roller shaft and the pressing wall. The pressing wall surrounding the supply roller shaft can be used as a part that holds the seal.

[0013] The pressure wall may have ribs. The rib protrudes toward the pressing member when the developing cartridge is attached to the drum cartridge. The rib is pressed by the pressing member.

[0014] By providing the pressing wall with the rib, the pressing wall that receives the pressing force from the pressing member can be reinforced.

[0015] The rib may have an arc shape when viewed from the first direction.

[0016] By having the rib in an arc shape, the rib is less likely to get caught by the pressing member when the developer cartridge is attached to or detached from the drum cartridge, which makes it easier to attach and detach the developer cartridge to or from the drum cartridge.

[0017] A plurality of the ribs may be provided aligned in the first direction.

[0018] By providing a plurality of ribs aligned in the first direction, the developer cartridge can be stably pressed against the photosensitive drum when the pressing member presses the ribs. The pressing wall can be further reinforced by the plurality of ribs.

[0019] When the developing cartridge is attached to the drum cartridge, the pressing wall may be located on an imaginary line passing through the drum shaft and the developing roller shaft when viewed from the first direction.

[0020] Since the pressing wall is positioned on a virtual line passing through the drum shaft and the developing roller shaft, when the pressing wall is pressed by the pressing member, the developing roller can be pressed toward the drum shaft of the photosensitive drum.

[0021] The process cartridge may include a supply roller bearing into which the supply roller shaft is fitted, and the third wall may be aligned with the supply roller bearing in a direction perpendicular to both the first direction and the second direction.

[0022] The third wall is aligned with the supply roller bearing in a direction perpendicular to both the first direction and the second direction, so that the developing cartridge can be made compact in the first direction. This makes it possible to make the drum cartridge and the process cartridge compact in the first direction.

[0023] The pressing wall may be aligned with the supply roller in the first direction.

[0024] The process cartridge may further include a supply roller gear, and the pressing wall may be located between the supply roller gear and the side wall. The feed roller gear is located at one end of the feed roller shaft in the first direction. The feed roller gear is rotatable together with the feed roller about the feed roller axis.

[0025] When the developing cartridge is attached to the drum cartridge, the supply roller shaft may be located on an imaginary straight line passing through the drum shaft and the developing roller shaft when viewed from the first direction. Effect of the Invention

[0026] The developing cartridge can be pressed toward the photosensitive drum at a position close to the photosensitive drum by the pressing member. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a diagram illustrating an image forming apparatus in which a process cartridge is used. [Diagram 2] FIG. 2 is a diagram showing the image forming apparatus with the process cartridge removed. [Diagram 3] FIG. 2A is a perspective view showing a process cartridge, and FIG. 2B is a perspective view showing a drum cartridge and a developing cartridge. [Figure 4] FIG. 4 is a perspective view showing a lock lever and a pressing member of the drum cartridge. [Diagram 5] 4 is a cross-sectional view showing a first pressing member and a first pressing wall of the process cartridge. FIG. [Figure 6] 4 is a perspective view showing a first pressing wall and a second pressing wall of the developing cartridge. FIG. [Figure 7] 4 is a cross-sectional view showing a state in which the developing cartridge is lifted up from the drum cartridge. [Figure 8] FIG. 2 is an exploded perspective view showing one end of the developing cartridge. [Figure 9] FIG. 2 is a cross-sectional perspective view showing one end of the process cartridge. [Figure 10] 2 is a cross-sectional view showing one end and the other end of the process cartridge. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Next, an embodiment will be described. As shown in FIG. 1, the image forming apparatus 1 includes a housing 2, a sheet supplying section 3, an exposure device 4, a process cartridge 5, and a fixing device 8.

[0029] The sheet supply unit 3 is located at the bottom inside the housing 2. The sheet supply unit 3 includes a sheet tray 31, a pressure plate 32, and a sheet supply mechanism 33. The sheet tray 31 stores sheets S such as paper. The pressure plate 32 pushes the sheets S in the sheet tray 31 upward. The sheet supply mechanism 33 supplies the sheets S pushed up by the pressure plate 32 toward the process cartridge 5.

[0030] The exposure device 4 is located above the sheet tray 31. The exposure device 4 includes a light source, a deflector, a lens, a mirror, etc. The exposure device 4 emits a light beam as shown by the imaginary line to expose the surface of the photosensitive drum 61.

[0031] The process cartridge 5 is located above the sheet supply mechanism 33. The process cartridge 5 includes a drum cartridge 6 and a developing cartridge .

[0032] The drum cartridge 6 includes a photosensitive drum 61, a charger 62, a transfer roller 63, and a drum frame 65. The photosensitive drum 61 is rotatable about a drum shaft 61X extending in a first direction. In this embodiment, the first direction corresponds to the left-right direction of the image forming apparatus 1.

[0033] The charger 62 charges the surface of the photosensitive drum 61. The transfer roller 63 is rotatable about a transfer roller shaft 63X that extends in the first direction. The drum frame 65 holds the photosensitive drum 61, the charger 62, and the transfer roller 63.

[0034] The developing cartridge 7 includes a developing roller 71 , a supply roller 72 , a layer thickness regulating blade 73 , an agitator 74 , and a developing frame 75 .

[0035] The developing roller 71 is rotatable about a developing roller shaft 71X that extends in the first direction. The supply roller 72 is rotatable about a supply roller shaft 72X that extends in the first direction. The layer thickness regulating blade 73 regulates the thickness of the toner layer on the developing roller 71 to a constant thickness.

[0036] The developing frame 75 holds the developing roller 71, the supply roller 72, the layer thickness regulating blade 73, and the agitator 74. The developing frame 75 is capable of containing toner. Specifically, the developing frame 75 has a toner containing portion 76 capable of containing toner.

[0037] The agitator 74 is rotatable about an agitator shaft 74X extending in the first direction. The agitator 74 rotates to agitate the toner in the toner containing portion 76. The supply roller 72 supplies the toner contained in the toner containing portion 76 to the developing roller 71.

[0038] The fixing device 8 is located above the process cartridge 5. The fixing device 8 includes a heating roller 81 and a pressure roller 82. The heating roller 81 heats the sheet S. The pressure roller 82 sandwiches the sheet S between the heating roller 81 and the pressure roller 82.

[0039] The image forming apparatus 1 charges the surface of the photosensitive drum 61 with the charger 62. Next, the image forming apparatus 1 exposes the charged surface of the photosensitive drum 61 to a light beam emitted from the exposure device 4. As a result, an electrostatic latent image based on image data is formed on the photosensitive drum 61. Next, the image forming apparatus 1 supplies toner from the development roller 71 to the photosensitive drum 61. As a result, a toner image is formed on the photosensitive drum 61.

[0040] Thereafter, the image forming apparatus 1 transports the sheet S supplied from the sheet supply unit 3 between the photosensitive drum 61 and the transfer roller 63. As a result, the toner image formed on the photosensitive drum 61 is transferred to the sheet S. Thereafter, the image forming apparatus 1 transports the sheet S, onto which the toner image has been transferred, between the heating roller 81 and the pressure roller 82. As a result, the toner image transferred to the sheet S is fixed to the sheet S.

[0041] The image forming apparatus 1 discharges the sheet S on which the toner image has been fixed by a discharge roller 9 onto a discharge tray 2A.

[0042] The housing 2 has a housing body 21 and a cover 22. The housing body 21 has an opening 21A. The cover 22 opens and closes the opening 21A. The cover 22 is movable relative to the housing body 21 between a closed position shown in FIG. 1 and an open position shown in FIG. 2. Specifically, the cover 22 is rotatable relative to the housing body 21 between the closed position and the open position. The closed position is a position where the opening 21A is closed. The open position is a position where the opening 21A is opened.

[0043] 2, the process cartridge 5 is detachable from the housing 2. Specifically, the process cartridge 5 is detachable from the housing main body 21 through an opening 21A with the cover 22 in the open position.

[0044] As shown in Figures 3(a) and (b), the developing cartridge 7 is detachable from the drum cartridge 6. Figure 3(a) shows the process cartridge 5 in which the developing cartridge 7 is attached to the drum cartridge 6. Figure 3(b) shows the state in which the developing cartridge 7 has been removed from the drum cartridge 6.

[0045] In the drawings referred to below, the first, second, and third directions are indicated by the side with an arrow and the other side without an arrow. The second direction is perpendicular to the first direction. The third direction is perpendicular to both the first and second directions.

[0046] 4, the drum cartridge 6 further includes a lock lever 140, and a first pressing member 150A and a second pressing member 150B as pressing members. The drum frame 65 has a first drum end 65A and a second drum end 65B.

[0047] The first drum end 65A is an end of the drum frame 65 that is closer to the photosensitive drum 61 in the third direction. In other words, the first drum end 65A is the other end of the drum frame 65 in the third direction. The second drum end 65B is an end of the drum frame 65 that is farther from the photosensitive drum 61 in the third direction. In other words, the second drum end 65B is one end of the drum frame 65 in the third direction.

[0048] The lock lever 140 locks the developer cartridge 7 to the drum cartridge 6 when the developer cartridge 7 is attached to the drum cartridge 6. The lock lever 140 is located at the other end in the first direction of the drum frame 65. The lock lever 140 is located at a position closer to the second drum end 65B than the photosensitive drum 61 in the third direction.

[0049] The first pressing member 150A and the second pressing member 150B press the developing cartridge 7 toward the photosensitive drum 61 in a state in which the developing cartridge 7 is attached to the drum cartridge 6. As a result, the first pressing member 150A and the second pressing member 150B press the developing roller 71 against the photosensitive drum 61.

[0050] The first pressing member 150A is located at one end in the first direction of the drum frame 65. The second pressing member 150B is located at the other end in the first direction of the drum frame 65. The first pressing member 150A and the second pressing member 150B are located at positions closer to the photosensitive drum 61 than the lock lever 140 is in the third direction. The first pressing member 150A and the second pressing member 150B have structures symmetrical to each other in the first direction.

[0051] 5, the first pressing member 150A has a pressing member body 151 and a spring 152. Similarly, the second pressing member 150B (see FIG. 10) has a pressing member body 151 and a spring 152.

[0052] The pressing member body 151 comes into contact with the developing cartridge 7 when the developing cartridge 7 is attached to the drum cartridge 6. The pressing member body 151 is held by the drum frame 65. The pressing member body 151 is capable of linearly moving relative to the drum frame 65 along the third direction.

[0053] The spring 152 is located between the pressing member body 151 and the second drum end 65B of the drum frame 65. The spring 152 biases the pressing member body 151 toward the other of the third direction. The spring 152 is, for example, a compression coil spring.

[0054] 5 and 6, the developing frame 75 has a first pressing wall 220A and a second pressing wall 220B as pressing walls. The developing frame 75 also has a first developing end 75A and a second developing end 75B.

[0055] The first developing end 75A is an end of the developing frame 75 that is closer to the photosensitive drum 61 in the third direction when the developing cartridge 7 is attached to the drum cartridge 6. In other words, the first developing end 75A is the other end of the developing frame 75 in the third direction.

[0056] The second developing end 75B is an end of the developing frame 75 that is farther from the photosensitive drum 61 in the third direction when the developing cartridge 7 is attached to the drum cartridge 6. In other words, the second developing end 75B is one end of the developing frame 75 in the third direction.

[0057] The first pressing wall 220A is pressed by the first pressing member 150A in a state in which the developing cartridge 7 is attached to the drum cartridge 6. The first pressing wall 220A is located at one end of the developing frame 75 in the first direction.

[0058] The second pressing wall 220B is pressed by a second pressing member 150B (see FIG. 10) in a state in which the developing cartridge 7 is attached to the drum cartridge 6. The second pressing wall 220B is located at the other end of the developing frame 75 in the first direction.

[0059] 5, when the developing cartridge 7 is attached to the drum cartridge 6, the first pressing wall 220A is aligned in a straight line with the photosensitive drum 61 and the developing roller 71 as viewed from the first direction. More specifically, when the developing cartridge 7 is attached to the drum cartridge 6, the first pressing wall 220A is positioned on an imaginary straight line L passing through the drum shaft 61X and the developing roller shaft 71X as viewed from the first direction. The same is true for the second pressing wall 220B.

[0060] The developing roller 71 has a developing roller shaft 71A and a developing roller main body 71B. The developing roller shaft 71A extends in a first direction. The developing roller shaft 71A is made of metal, for example. The developing roller main body 71B covers the outer circumferential surface of the developing roller shaft 71A. The developing roller main body 71B is made of rubber, for example.

[0061] The supply roller 72 has a supply roller shaft 72A and a supply roller body 72B. The supply roller shaft 72A extends in a first direction. The supply roller shaft 72A is made of metal, for example. The supply roller body 72B covers the outer circumferential surface of the supply roller shaft 72A. The supply roller body 72B is made of sponge, for example.

[0062] When the developing cartridge 7 is attached to the drum cartridge 6, the supply roller 72 is aligned in a straight line with the photosensitive drum 61 and the developing roller 71 as viewed from the first direction. More specifically, when the developing cartridge 7 is attached to the drum cartridge 6, the supply roller shaft 72A is positioned on an imaginary straight line L as viewed from the first direction.

[0063] The lock lever 140 is movable with respect to the drum frame 65 between a locked position shown in Fig. 5 and an unlocked position shown in Fig. 7. Specifically, the lock lever 140 is swingable with respect to the drum frame 65 between the locked position and the unlocked position.

[0064] The lock lever 140 has a shaft portion 141 , a lock portion 142 , a push-up portion 143 , and an operating portion 144 .

[0065] The shaft portion 141 is rotatable about a lever shaft 140X that extends in the first direction. The shaft portion 141 is supported by the drum frame 65 so as to be rotatable.

[0066] 5 is located at the locked position, the locking portion 142 locks the developing cartridge 7 to the drum frame 65. When the locking lever 140 is located at the locked position, the locking portion 142 extends from the shaft portion 141 toward one side in the second direction. The locking portion 142 has a recess 142A into which the protrusion 77 of the developing cartridge 7 fits.

[0067] The operation unit 144 is operated by a user when moving the lock lever 140 from the locked position to the unlocked position. The operation unit 144 extends from the lock unit 142 toward one side in the second direction and toward one side in the third direction when the lock lever 140 is in the locked position.

[0068] When the lock lever 140 moves from the locked position to the unlocked position, the push-up portion 143 comes into contact with the developer cartridge 7 and pushes up the developer cartridge 7. When the lock lever 140 is in the locked position, the push-up portion 143 extends from the shaft portion 141 toward the other side in the second direction.

[0069] The lock lever 140 is located at the lock position when the developer cartridge 7 is attached to the drum cartridge 6. At this time, the protrusion 77 of the developer cartridge 7 fits into the recess 142A of the lock portion 142. As a result, the developer cartridge 7 is locked with respect to the drum cartridge 6.

[0070] 7, the recess 142A of the locking portion 142 is released from the protrusion 77 of the developer cartridge 7, and the push-up portion 143 pushes up the developer cartridge 7. As a result, the developer cartridge 7 is released from the lock state relative to the drum cartridge 6, and mainly the second development end portion 75B of the developer cartridge 7 is separated from the drum frame 65. As a result, the developer cartridge 7 is removed from the drum cartridge 6.

[0071] 8, the developer cartridge 7 further includes a first seal 230A as a seal, and a first bearing 240A. The developer frame 75 includes a first side wall 210A as a side wall.

[0072] The first side wall 210A is located at one end in the first direction of the developing frame 75. In this embodiment, the first side wall 210A is perpendicular to the first direction.

[0073] The first pressing wall 220A protrudes from the first side wall 210A in one direction in the first direction. The first pressing wall 220A surrounds one end of the supply roller shaft 72A in the first direction. Specifically, the first pressing wall 220A has a first wall 221, a second wall 222, and a third wall 223.

[0074] The first wall 221 and the second wall 222 extend in the third direction. The second wall 222 faces the first wall 221 in the second direction. One end of the supply roller shaft 72A in the first direction is located between the first wall 221 and the second wall 222. The first wall 221 is located on one end of the supply roller shaft 72A in the second direction. The second wall 222 is located on the other end of the supply roller shaft 72A in the second direction.

[0075] The third wall 223 extends in the second direction. The third wall 223 connects one end of the first wall 221 and one end of the second wall 222. Specifically, the third wall 223 connects one end of the first wall 221 in the third direction and one end of the second wall 222 in the third direction.

[0076] The third wall 223 protrudes in the first direction further than the first wall 221 and the second wall 222. Specifically, the dimension of the third wall 223 in the first direction is larger than the dimension of the first wall 221 in the first direction and is larger than the dimension of the second wall 222 in the first direction. In this embodiment, the dimension of the first wall 221 in the first direction and the dimension of the second wall 222 in the first direction are the same. The third wall 223 directly faces the supply roller shaft 72A.

[0077] The first pressing wall 220A further has a rib 224. The rib 224 protrudes toward the first pressing member 150A (see FIG. 5) when the developing cartridge 7 is attached to the drum cartridge 6. Specifically, the rib 224 protrudes from the third wall 223 in one direction in the third direction.

[0078] A plurality of ribs 224 are provided lined up in the first direction. In this embodiment, two ribs 224 are provided lined up in the first direction. The rib 224 has an arc shape when viewed from the first direction. In detail, one surface of the rib 224 in the third direction has an arc shape when viewed from the first direction.

[0079] 9, the third wall 223 of the first pressing wall 220A is pressed by the first pressing member 150A when the developing cartridge 7 is attached to the drum cartridge 6. In detail, when the developing cartridge 7 is attached to the drum cartridge 6, the rib 224 protruding from the third wall 223 of the first pressing wall 220A is pressed by the first pressing member 150A.

[0080] The first seal 230A prevents toner from leaking from between the supply roller shaft 72A and the first pressing wall 220A. The first seal 230A is located between the supply roller shaft 72A and the first pressing wall 220A. The first pressing wall 220A holds the first seal 230A. Specifically, the first pressing wall 220A holds the first seal 230A between the first wall 221 (see FIG. 5) and the second wall 222.

[0081] The first seal 230A is attached to the developing frame 75 together with the supply roller 72 before the developing roller 71 is attached to the developing frame 75. In detail, the first seal 230A is attached to the developing frame 75 together with the supply roller 72 in a state in which the supply roller shaft 72A is inserted into the through hole 231 (see FIG. 8). The first seal 230A is attached to the inside of the first pressing wall 220A, facing one side in the third direction from the first developing end portion 75A of the developing frame 75.

[0082] 8, the first bearing 240A rotatably supports the developing roller 71 and the supply roller 72. The first bearing 240A has a first developing bearing 241A and a first supply bearing 242A serving as a supply roller bearing.

[0083] The first developing bearing 241A rotatably supports the developing roller 71. One end of the developing roller shaft 71A in the first direction is fitted into the first developing bearing 241A.

[0084] The first supply bearing 242A rotatably supports the supply roller 72. One end of the supply roller shaft 72A in the first direction is fitted into the first supply bearing 242A. In this embodiment, the first development bearing 241A and the first supply bearing 242A are integrally formed.

[0085] 10, third wall 223 of first pressing wall 220A is aligned with first supply bearing 242A in the third direction. Third wall 223 of first pressing wall 220A is located on one side of first supply bearing 242A in the third direction.

[0086] The developing cartridge 7 further includes a supply roller gear 72G. The supply roller gear 72G is rotatable together with the supply roller 72 about the supply roller shaft 72X. The supply roller gear 72G is located at one end of the supply roller shaft 72A in the first direction. The supply roller gear 72G is fixed to the supply roller shaft 72A. The supply roller 72 rotates when a driving force is input to the supply roller gear 72G.

[0087] The first pressing wall 220A is located between the supply roller gear 72G and the first side wall 210A of the developing frame 75. The first pressing wall 220A is located on one side of the first side wall 210A in the first direction. The first pressing wall 220A is located on the other side of the supply roller gear 72G in the first direction.

[0088] The first pressing wall 220A is aligned with the supply roller 72 in the first direction. The first pressing wall 220A is located on one side of the supply roller 72 in the first direction. Specifically, the first pressing wall 220A is aligned with the supply roller main body 72B in the first direction. The first pressing wall 220A is located on one side of the supply roller main body 72B in the first direction.

[0089] The developer cartridge 7 further includes a second seal 230B and a second bearing 240B. The developer frame 75 has a second side wall 210B.

[0090] The second side wall 210B is located at the other end in the first direction of the developing frame 75. In this embodiment, the second side wall 210B is perpendicular to the first direction. The second side wall 210B faces the first side wall 210A in the first direction.

[0091] The second pressing wall 220B protrudes from the second side wall 210B toward the other side in the first direction. The second pressing wall 220B surrounds the other end of the supply roller shaft 72A in the first direction. The second pressing wall 220B has a structure symmetrical to the first pressing wall 220A in the first direction. Specifically, like the first pressing wall 220A, the second pressing wall 220B has a first wall 221, a second wall 222, a third wall 223, and a rib 224 (some parts are not shown).

[0092] The other end of the supply roller shaft 72A in the first direction is located between a first wall 221 and a second wall 222 (not shown) of the second pressing wall 220B. The rib 224 of the second pressing wall 220B protrudes toward the second pressing member 150B when the developing cartridge 7 is attached to the drum cartridge 6.

[0093] The third wall 223 of the second pressing wall 220B is pressed by the second pressing member 150B when the developing cartridge 7 is attached to the drum cartridge 6. In detail, when the developing cartridge 7 is attached to the drum cartridge 6, the rib 224 of the second pressing wall 220B is pressed by the second pressing member 150B.

[0094] The second seal 230B prevents toner from leaking from between the supply roller shaft 72A and the second pressing wall 220B. The second seal 230B is located between the supply roller shaft 72A and the second pressing wall 220B. The second pressing wall 220B holds the second seal 230B. The second seal 230B is attached to the developing frame 75 in the same manner as the first seal 230A.

[0095] The second bearing 240B includes a second development bearing 241B and a second supply bearing 242B. The second developing bearing 241B rotatably supports the developing roller 71. The other end of the developing roller shaft 71A in the first direction is fitted into the second developing bearing 241B.

[0096] The second supply bearing 242B rotatably supports the supply roller 72. The other end of the supply roller shaft 72A in the first direction is fitted into the second supply bearing 242B. In this embodiment, the second development bearing 241B and the second supply bearing 242B are integrally formed.

[0097] Third wall 223 of second pressing wall 220B is aligned with second supply bearing 242B in the third direction. Third wall 223 of second pressing wall 220B is located on one side of second supply bearing 242B in the third direction.

[0098] The second pressing wall 220B is aligned with the supply roller 72 in the first direction. The second pressing wall 220B is located on the other side of the supply roller 72 in the first direction. Specifically, the second pressing wall 220B is aligned with the supply roller main body 72B in the first direction. The second pressing wall 220B is located on the other side of the supply roller main body 72B in the first direction.

[0099] Next, the effects of the embodiment will be described. The pressing walls 220A, 220B surrounding the end of the supply roller shaft 72A in the first direction are pressed by the pressing members 150A, 150B, so that the developing cartridge 7 can be pressed toward the photosensitive drum 61 at a position close to the photosensitive drum 61 by the pressing members 150A, 150B.

[0100] Because the distance from the pressing walls 220A, 220B to the photosensitive drum 61 is short, it is possible to suppress deformation of the drum frame 65 due to the reaction force of the pressing forces of the pressing members 150A, 150B that the pressing members 150A, 150B receive from the developing cartridge 7. This makes it possible to reduce loss of the pressing force due to deformation of the drum frame 65. Because the loss of the pressing force can be reduced, the developing cartridge 7 can be pressed toward the photosensitive drum 61 with a small pressing force. In other words, even if the urging force of the springs 152 of the pressing members 150A, 150B is small, the developing cartridge 7 can be pressed toward the photosensitive drum 61 with a sufficient pressing force.

[0101] In the process cartridge 5, the pressing walls 220A, 220B of the developing cartridge 7 pressed by the pressing members 150A, 150B are located on the side surface of the developing frame 75 in the first direction, not on the second developing end portion 75B of the developing frame 75. This allows the toner accommodating portion 76 of the developing frame 75 to be enlarged in one direction in the second direction and / or one direction in the third direction. This allows the toner accommodating volume of the developing cartridge 7 to be increased.

[0102] Since the dimension in the first direction of the third wall 223 pressed by the pressing members 150A and 150B is large, the developing cartridge 7 can be stably pressed toward the photosensitive drum 61 when the third wall 223 is pressed by the pressing members 150A and 150B.

[0103] By providing the seals 230A, 230B positioned between the supply roller shaft 72A and the pressing walls 220A, 220B, it is possible to prevent toner from leaking between the supply roller shaft 72A and the pressing walls 220A, 220B. The pressing walls 220A, 220B surrounding the supply roller shaft 72A can be used as portions for holding the seals 230A, 230B.

[0104] The pressing walls 220A, 220B have the ribs 224, so that the pressing walls 220A, 220B that receive the pressing forces from the pressing members 150A, 150B can be reinforced.

[0105] Since the rib 224 has an arc shape, the rib 224 is less likely to get caught by the pressing members 150A, 150B when the developing cartridge 7 is attached to or detached from the drum cartridge 6. This allows the developing cartridge 7 to be easily attached to or detached from the drum cartridge 6.

[0106] By providing a plurality of ribs 224 aligned in the first direction, when the ribs 224 are pressed by the pressing members 150A, 150B, the developing cartridge 7 can be stably pressed toward the photosensitive drum 61. The pressing walls 220A, 220B can be further reinforced by the plurality of ribs 224.

[0107] Since the pressing walls 220A, 220B are positioned on the imaginary line L passing through the drum shaft 61X and the developing roller shaft 71X, the developing roller 71 can be pressed toward the drum shaft 61X of the photosensitive drum 61 when the pressing walls 220A, 220B are pressed by the pressing members 150A, 150B.

[0108] By aligning the third wall 223 with the supply bearings 242A and 242B in the third direction, the developing cartridge 7 can be made more compact in the first direction compared to a case in which the third wall and the supply bearings are misaligned in the first direction. This allows the drum cartridge 6 and the process cartridge 5 to be made more compact in the first direction.

[0109] Although the embodiment has been described above, the process cartridge can be modified as appropriate as exemplified below.

[0110] In the above embodiment, the rib 224 has an arc shape, but the rib may have, for example, a trapezoidal shape or a rectangular shape.

[0111] In the above embodiment, the first pressing wall 220A has two ribs 224, but for example, the first pressing wall may have three or more ribs. The first pressing wall may have only one rib. The first pressing wall may have no ribs. The same applies to the second pressing wall.

[0112] In the above-described embodiment, the third wall 223 has a larger dimension in the first direction than the first wall 221 and the second wall 222, but, for example, the third wall may have the same dimension in the first direction as at least one of the first wall and the second wall. In other words, at least one of the first wall and the second wall may have the same dimension in the first direction as the third wall. Also, the first wall and the second wall may have different dimensions in the first direction.

[0113] In the above embodiment, the third wall 223 of the first pressing wall 220A is located between the supply roller gear 72G and the first side wall 210A so as to overlap with the supply roller gear 72G when viewed from the first direction. However, for example, the third wall may be located at a position not overlapping with the supply roller gear when viewed from the first direction.

[0114] In the above embodiment, the first pressing wall 220A is aligned with the supply roller 72 in the first direction so as to overlap with the supply roller 72 when viewed from the first direction, but for example, the first pressing wall may be located at a position not overlapping with the supply roller when viewed from the first direction. The same applies to the second pressing wall.

[0115] In the above embodiment, the first pressing wall 220A is aligned with the first supply bearing 242A in the third direction, but for example, the first pressing wall may be located at a position different from the first supply bearing in the first direction. The same applies to the second pressing wall and the second supply bearing.

[0116] In the above embodiment, the pressing walls 220A and 220B are located on the imaginary straight line L, but for example, the pressing walls do not have to be located on the imaginary straight line. Similarly, the supply roller shaft does not have to be located on the imaginary straight line.

[0117] In the above embodiment, the developing cartridge 7 has a toner storage section 76 capable of storing toner, but for example, the developing cartridge may not have a toner storage section. A developing cartridge without a toner storage section may have a detachable toner cartridge capable of storing toner. Furthermore, the process cartridge may have a drum cartridge, a developing cartridge, and a toner cartridge.

[0118] The elements described in the above embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0119] 5 Process cartridge 6 Drum Cartridge 7 Developer cartridge 61 Photosensitive drum 61X Drum shaft 71 Developing roller 71X Developing roller shaft 72 Supply roller 72A Supply roller shaft 72X Supply roller shaft 75 Developing Frame 150A First pressing member (pressing member) 210A First side wall (side wall) 220A First pressing wall (pressing wall)

Claims

1. A process cartridge including a drum cartridge and a developing cartridge detachably attached to the drum cartridge, The drum cartridge is a photosensitive drum rotatable about a drum axis extending in a first direction; a pressing member that presses the developing cartridge toward the photosensitive drum when the developing cartridge is attached to the drum cartridge, The developing cartridge is a developing roller rotatable about a developing roller axis extending in the first direction; a supply roller rotatable about a supply roller axis extending in the first direction, the supply roller having a supply roller shaft extending in the first direction; 1. A developing frame comprising: a side wall located at one end of the developing frame in the first direction; a developing frame having a pressing wall protruding from the side wall in the first direction, the pressing wall surrounding one end of the supply roller shaft in the first direction, a pressing member that presses the pressing wall when the developing cartridge is attached to the drum cartridge;

2. The pressing wall is The first wall, a second wall facing the first wall in a second direction perpendicular to the first direction; a third wall connecting one end of the first wall and one end of the second wall, one end of the supply roller shaft in the first direction is located between the first wall and the second wall, 2. The process cartridge according to claim 1, wherein said third wall is pressed by said pressing member when said developing cartridge is mounted in said drum cartridge.

3. 3. A process cartridge according to claim 2, wherein a dimension of said third wall in said first direction is larger than a dimension of said first wall in said first direction and is also larger than a dimension of said second wall in said first direction.

4. the developing frame is capable of containing a toner; 2. A process cartridge according to claim 1, wherein said developing cartridge further comprises a seal located between said supply roller shaft and said pressing wall.

5. 2. The process cartridge according to claim 1, wherein the pressing wall has a rib that protrudes toward the pressing member and is pressed by the pressing member when the developing cartridge is attached to the drum cartridge.

6. 6. A process cartridge according to claim 5, wherein said rib has an arc shape when viewed from said first direction.

7. 7. A process cartridge according to claim 5, wherein the rib is a plurality of ribs arranged in the first direction.

8. 2. The process cartridge according to claim 1, wherein, when the developing cartridge is attached to the drum cartridge, the pressing wall is located on a virtual straight line passing through the drum shaft and the developing roller shaft when viewed from the first direction.

9. a supply roller bearing into which the supply roller shaft is fitted, 4. A process cartridge according to claim 2, wherein the third wall is aligned with the supply roller bearing in a direction perpendicular to both the first direction and the second direction.

10. 2. A process cartridge according to claim 1, wherein said pressing wall is aligned with said supply roller in said first direction.

11. a supply roller gear located at one end of the supply roller shaft in the first direction and rotatable together with the supply roller about the supply roller shaft; 2. A process cartridge according to claim 1, wherein said pressing wall is located between said supply roller gear and said side wall.

12. 2. A process cartridge according to claim 1, wherein, when the developing cartridge is attached to the drum cartridge, when viewed from the first direction, the supply roller shaft is located on a virtual straight line passing through the drum axis and the developing roller axis.

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