Developing cartridge

Abstract

A developing cartridge (1) attachable to a drum cartridge (2) includes: a developing roller (30); a housing (10) including a first frame (15) and a second frame (16) that support the developing roller (30); and a separation member (60) that is movable relative to the housing (10) in the first direction. The separation member (60) includes a separation shaft (63) and a first inclined surface (611) located at one end of the separation member (60) in the first direction. The first frame (15) has load receiving surfaces (17, 18) that come into contact with the separation shaft (63) to receive a load in a second direction crossing the first direction from the separation shaft (63) when the separation member (60) moves in the first direction and the first inclined surface (611) comes into contact with the drum cartridge (2) in a state in which the developing cartridge (1) is attached to the drum cartridge (2).

Description

Technical Field

[0001] The present disclosure relates to a developing cartridge. Background Art

[0002] Electrophotographic image forming apparatuses such as laser printers or LED printers are known in the art. Conventional image forming apparatuses include a developing cartridge and a drum cartridge. The developing cartridge includes a developing roller. The drum cartridge includes a photosensitive drum. When the developing cartridge is attached to the drum cartridge, the developing roller contacts the photosensitive drum.

[0003] The developing cartridge of the above-described conventional image forming apparatus further includes a separating member. The separating member is movable relative to the housing of the developing cartridge. When the separating member moves in a state where the developing cartridge is attached to the drum cartridge, the separating member contacts the frame of the drum cartridge. As a result, the developing cartridge moves relative to the drum cartridge in a separating direction, thereby separating the developing roller from the photosensitive drum.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-179128

[0007] Technical Problems to be Solved by the Invention

[0008] The housing of the above-described developing cartridge is composed of two frames, and one of the two frames supports the developing roller. In the conventional image forming apparatus, the separating member contacts one of the two frames that does not support the developing roller. Therefore, when the separating member moves and contacts the drum cartridge, the frame that does not support the developing roller receives a load from the separating member in the separating direction.

[0009] In this structure, there is a problem that the accuracy of the movement of the developing roller relative to the drum cartridge depends on the fixing accuracy of the two frames of the developing cartridge and the dimensional accuracy of the two frames. Summary of the Invention

[0010] In view of the above viewpoints, an object of the present disclosure is to provide a technique that enables a developing roller to move relative to a drum cartridge with high accuracy.

[0011] Means for Solving the Technical Problems

[0012] (1)To achieve the above and other objects, according to aspect (1), there is provided a developing cartridge that can be attached to a drum cartridge. The developing cartridge includes: a developing roller; a housing; and a separating member. The developing roller is rotatable about an axis extending in a first direction. The housing is configured to accommodate a developer. The housing has an end portion in a second direction, and the developing roller is located at the end portion of the housing. The second direction intersects the first direction. The housing includes a first frame and a second frame. The first frame supports the developing roller. The second frame is fixed to the first frame. The separating member is movable relative to the housing in the first direction. The separating member includes a separating shaft rod and a first inclined surface. The separating shaft rod extends in the first direction. The first inclined surface is located at an end portion of the separating member in the first direction. The first inclined surface extends away from the developing roller in the second direction as it extends toward the other end portion of the separating member in the first direction. The first frame has a load-bearing surface that faces the separating shaft rod in the second direction. In a state where the developing cartridge is attached to the drum cartridge, when the separating member moves in the first direction and the first inclined surface contacts the drum cartridge, the load-bearing surface contacts the separating shaft rod to receive a load in the second direction from the separating shaft rod.

[0013] (2)According to aspect (2), in the developing cartridge of aspect (1), preferably: the first frame includes a first developing guide roller that is rotatable about an axis extending in a third direction, the third direction intersecting both the first direction and the second direction, the first developing guide roller contacts the separating shaft rod, the first developing guide roller rotates in response to the movement of the separating shaft rod in the first direction, and the load-bearing surface includes the outer surface of the first developing guide roller.

[0014] (3)According to aspect (3), in the developing cartridge of aspect (2), preferably: the first frame further has a support groove that supports an end portion of the first developing guide roller in the third direction.

[0015] (4)According to aspect (4), in the developing cartridge of aspect (2) or aspect (3), preferably: the first frame further includes a second developing guide roller that is separated from the first developing guide roller in the first direction, the second developing guide roller is rotatable about an axis extending in the third direction, the second developing guide roller contacts the separating shaft rod, the second developing guide roller rotates in response to the movement of the separating shaft rod in the first direction, and the load-bearing surface further includes the outer surface of the second developing guide roller.

[0016] (5)According to aspect (5), in the developing cartridge of any one of aspects (1) to (4), preferably: the separating member further includes a spring seat that extends away from the first inclined surface in the second direction. It is also preferred that: the developing cartridge further includes a return spring configured to expand and contract in the first direction, and the return spring has one end portion in the first direction that contacts the spring seat and the other end portion in the first direction that contacts the housing.

[0017] (6)According to aspect (6), in the developing cartridge of aspect (5), preferably: the other end portion of the return spring in the first direction contacts the first frame.

[0018] (7)According to aspect (7), in the developing cartridge of aspect (5) or aspect (6), preferably: the load-bearing surface is located at a position where the distance from the load-bearing surface to the other end portion of the separating member in the first direction is closer than the distance from the return spring to the other end portion of the separating member in the first direction.

[0019] (8)According to aspect (8), in the developing cartridge of any one of aspects (5) to (7), preferably: the return spring is separated from the outer peripheral surface of the separating shaft rod and is further located at a position radially outside.

[0020] (9)According to aspect (9), in the developing cartridge of any one of aspects (5) to (8), preferably: the housing has one end portion and the other end portion in the first direction, and among the one end portion and the other end portion of the housing in the first direction, the return spring is only located at the one end portion of the housing in the first direction.

[0021] (10)According to aspect (10), in the developing cartridge of aspect (9), preferably: the developing cartridge further includes: a gear located at the one end portion of the housing in the first direction; and a gear cover attached to the one end portion of the housing in the first direction and covering the gear. It is also preferred that: the return spring is also covered by the gear cover.

[0022] (11)According to aspect (11), in the developing cartridge of any one of aspects (5) to (10), preferably: the return spring is a compression coil spring.

[0023] (12)According to aspect (12), in the developing cartridge of any one of aspects (1) to (11), preferably: the housing further includes ribs that protrude from the outer surface of the housing and cover a part of the separating shaft rod.

[0024] (13)According to aspect (13), in the developing cartridge of aspect (12), preferably: the ribs are located at the center of the housing in the first direction.

[0025] (14)According to aspect (14), in the developing cartridge of aspect (12) or aspect (13), preferably: the second frame includes ribs.

[0026] (15)According to aspect (15), in the developing cartridge of aspect (14), preferably: the second frame has a guide groove that extends in a first direction, the separation shaft rod is located in the guide groove, and the rib covers the portion of the separation shaft rod that is located in the guide groove.

[0027] (16)According to aspect (16), in the developing cartridge of any one of aspects (12) to (15), preferably: the separation shaft rod has a small-diameter portion whose diameter is smaller than the diameter of the rest of the separation shaft rod, and the rib covers the small-diameter portion.

[0028] (17)According to aspect (17), in the developing cartridge of any one of aspects (12) to (16), preferably: the housing includes: a first rib, which is a rib; and a second rib, which is a rib located at a position separated from the first rib in a second direction, and, wherein, a portion of the separation shaft rod is located between the first rib and the second rib in the second direction.

[0029] (18)According to aspect (18), in the developing cartridge of any one of aspects (1) to (17), preferably: the developing cartridge further includes: a gear, which is located at one end portion of the housing in the first direction; a gear cover, which is attached to one end portion of the housing in the first direction and covers the gear; a memory, which has an electrical contact surface; a holder, which is located at the other end portion of the housing in the first direction and holds the electrical contact surface; and a holder cover, which is attached to the other end portion of the housing in the first direction and covers at least a portion of the holder. It is also preferred that: the separating member is supported by the gear cover and the holder cover.

[0030] (19)According to aspect (19), in the developing cartridge of any one of aspects (1) to (18), preferably: the separation shaft rod has a recess that is recessed away from the developing roller in the second direction, and the recess is juxtaposed with a first inclined surface in the first direction.

[0031] (20)According to aspect (20), in the developing cartridge of aspect (19), preferably: the recess is located at a position where the distance of the recess from the other end portion of the separating member in the first direction is closer than the distance of the first inclined surface from the other end portion of the separating member in the first direction.

[0032] (21)According to aspect (21), in the developing cartridge of aspect (19) or aspect (20), preferably: the recess is located between the load-bearing surface and the first inclined surface in the first direction.

[0033] (22) According to embodiment (22), in the developing cartridge of any one of embodiments (1) to (21), preferably, the separating member further includes a protrusion that protrudes outward in the radial direction of the separating shaft rod, and in a state where the developing cartridge is attached to the drum cartridge, the protrusion contacts the drum cartridge in the first direction.

[0034] (23) According to embodiment (23), in the developing cartridge of any one of embodiments (1) to (22), preferably, the separating shaft rod is made of resin.

[0035] (24) According to embodiment (24), in the developing cartridge of any one of embodiments (1) to (23), preferably, the drum cartridge includes a photosensitive drum, and when the separating member moves in the first direction in a state where the developing cartridge is attached to the drum cartridge, the developing roller separates from the photosensitive drum in the second direction.

[0036] (25) According to embodiment (25), there is also provided an image forming apparatus including: a developing cartridge according to embodiments (1) to (24); and a drum cartridge to which the developing cartridge can be attached. The drum cartridge has a contact surface that contacts the separating member when the separating member moves in the first direction in a state where the developing cartridge is attached to the drum cartridge.

[0037] (26) According to embodiment (26), in the image forming apparatus of embodiment (25), preferably, the drum cartridge includes: a photosensitive drum; a drum frame that supports the photosensitive drum, the drum frame having an end portion in the first direction; a metal plate to which the end portion of the drum frame in the first direction is fixed; and a side member that has a contact surface and is fixed to the metal plate.

[0038] (27) According to embodiment (27), in the image forming apparatus according to embodiment (26), preferably, the side member is fixed to the metal plate by a threaded member.

[0039] (28) According to embodiment (28), in the image forming apparatus according to embodiment (26) or (27), preferably, the drum cartridge further has another side member that is juxtaposed with the side member in the fourth direction, and the side member includes a plate-like portion that extends toward the other side member, and the plate-like portion is inserted between the other side member and the metal plate.

[0040] (29) According to embodiment (29), in the image forming apparatus according to embodiment (28), preferably, a gap is formed between the plate-like portion and the other side member in the first direction, and a gap is formed between the metal plate and the plate-like portion in the first direction.

[0041] (30)According to aspect (30), in an image forming apparatus according to any one of aspects (25) to (29), it is preferable that: in a state where the developing cartridge is attached to the drum cartridge, the contact surface is more outward in the first direction than the load bearing surface.

[0042] (31)According to aspect (31), in an image forming apparatus according to any one of aspects (25) to (30), it is preferable that: the drum cartridge further includes a first drum guide roller that is rotatable about an axis extending in a third direction that intersects both the first direction and the second direction. When the separating member moves in the first direction in a state where the developing cartridge is attached to the drum cartridge, the first drum guide roller contacts the first inclined surface, and the first drum guide roller rotates in response to the movement of the first inclined surface in the first direction. And, the contact surface includes the outer surface of the first drum guide roller.

[0043] (32)According to aspect (32), in the image forming apparatus according to aspect (31), it is preferable that: the separating member further includes a second inclined surface that is located at the other end in the first direction of the separating member. The second inclined surface extends away from the developing roller in the second direction as it extends toward the other end in the first direction of the separating member. The drum cartridge further includes a second drum guide roller that is separated from the first drum guide roller in the first direction. The second drum guide roller is rotatable about an axis extending in the third direction. When the separating member moves in the first direction in a state where the developing cartridge is attached to the drum cartridge, the second drum guide roller contacts the second inclined surface, and the second drum guide roller rotates in response to the movement of the second inclined surface in the first direction. And, the contact surface further includes the outer surface of the second drum guide roller.

[0044] (33)According to aspect (33), in an image forming apparatus according to any one of aspects (26) to (28), it is preferable that: the side member includes a developing pressing portion that applies a force to the developing cartridge toward the photosensitive drum.

[0045] (34)According to aspect (34), in an image forming apparatus according to any one of aspects (26) to (28), it is preferable that: the drum cartridge further includes: another photosensitive drum, the photosensitive drum and the another photosensitive drum are arranged in a fourth direction; another drum frame that supports the another photosensitive drum; and another side member.

[0046] (35)According to aspect (26), in the image forming apparatus according to aspect (34), it is preferable that: the image forming apparatus further includes a main frame to which the drum cartridge can be attached and detached. When the drum cartridge slides in the fourth direction relative to the main frame, the drum cartridge can be attached to and detached from the main frame.

[0047] Effects of the Invention

[0048] According to the methods (1) to (35), during the separation operation in which the developing roller moves relative to the drum cartridge, the first frame supporting the developing roller bears a load in the second direction. This structure allows the developing roller to move relative to the drum cartridge in the second direction with high precision.

[0049] In addition, according to the method (2), the frictional resistance generated due to the movement of the separation shaft in the first direction relative to the housing can be reduced.

[0050] In addition, according to the method (4), since the load in the second direction during the separation operation is borne by two parts in the developing cartridge, the developing roller can move precisely relative to the drum cartridge in the second direction.

[0051] In addition, according to the method (12), the deflection of the separation shaft toward the outside of the housing can be suppressed.

[0052] In addition, according to the method (19), the contact between the separation shaft and the drum cartridge can be suppressed.

[0053] In addition, according to the method (22), the separation member can be positioned relative to the drum cartridge in the first direction.

[0054] In addition, according to the method (28), the deformation of the side member can be suppressed.

[0055] In addition, according to the method (29), the expansion and contraction of the side member are allowed.

[0056] In addition, according to the method (31), the frictional resistance generated when the separation shaft moves in the first direction relative to the drum cartridge can be reduced.

[0057] In addition, according to the method (32), the developing cartridge can move more precisely relative to the drum cartridge in the second direction. Description of the Drawings

[0058] Figure 1 is a schematic diagram of the image forming apparatus.

[0059] Figure 2 is a perspective view of the developing cartridge according to an embodiment of the present disclosure.

[0060] Figure 3 is another perspective view of the developing cartridge according to the embodiment.

[0061] Figure 4 is a front view of the developing cartridge according to the embodiment.

[0062] Figure 5 is the sectional view of the developing cartridge according to the embodiment along Figure 4 the line V-V.

[0063] Figure 6 This is a view of the developing cartridge with the gear cover removed, as viewed from the first outer surface side in the first direction, according to this embodiment.

[0064] Figure 7 This is a partial perspective view of the developing cartridge with the gear cover removed, according to this embodiment.

[0065] Figure 8 This is a view of a portion near the first outer surface of the developing cartridge with the gear cover removed, as viewed from the first frame side in the fourth direction, according to this embodiment.

[0066] Figure 9 This is a partial perspective view of the developing cartridge with the gear cover and the separation member removed, according to this embodiment.

[0067] Figure 10 This is a partial perspective view of the developing cartridge with the storage component and the separation member removed, according to this embodiment.

[0068] Figure 11 This is a cross-sectional view of the developing cartridge according to this embodiment, taken along line XI-XI Figure 4 as indicated.

[0069] Figure 12 This is a cross-sectional view of the developing cartridge according to this embodiment, taken along line XII-XII Figure 4 as indicated.

[0070] Figure 13 This is a perspective view of the drum cartridge.

[0071] Figure 14 This is Figure 13 an enlarged view of region D in

[0072] Figure 15 This is Figure 13 an enlarged view of region E in

[0073] Figure 16 This is a cross-sectional view of the drum cartridge with the developing cartridge according to this embodiment attached, including the separation member.

[0074] Figure 17 This is another cross-sectional view of the drum cartridge with the developing cartridge according to this embodiment attached, including the separation member.

[0075] Figure 18 This is a partial perspective view of the developing cartridge with the gear cover and the separation member removed, according to the first modification. Detailed Description of the Embodiment

[0076] An embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0077] In the following description, the direction in which the rotation axis of the developing roller 30 extends is referred to as the "first direction". In addition, the direction in which one end portion of the housing 10 of the developing cartridge 1 where the developing roller 30 is located and the other end portion of the housing 10 are arranged is referred to as the "second direction". In addition, the direction in which the rotation axis of the first developing guide roller 17 extends is referred to as the "third direction". In addition, the direction in which the plurality of photosensitive drums 70 are arranged in the drum cartridge 2 is referred to as the "fourth direction".

[0078] The first direction and the second direction intersect each other. Preferably, the first direction and the second direction are orthogonal to each other. The first direction and the third direction intersect each other. Preferably, the first direction and the third direction are orthogonal to each other. The first direction and the fourth direction intersect each other. Preferably, the first direction and the fourth direction are orthogonal to each other. The second direction and the third direction intersect each other. The second direction and the fourth direction intersect each other. The third direction and the fourth direction intersect each other.

[0079] <1. Structure of the image forming apparatus 100>

[0080] Figure 1 is a schematic diagram of the image forming apparatus 100. The image forming apparatus 100 is an electrophotographic printer. Specifically, the image forming apparatus 100 is a laser printer or an LED printer. As Figure 1 shown, the image forming apparatus 100 includes a main frame 101, a drum cartridge 2, and four developing cartridges 1.

[0081] The four developing cartridges 1 can be attached to the drum cartridge 2. In addition, the drum cartridge 2 to which the four developing cartridges 1 are attached can be attached to the main frame 101. When the drum cartridge 2 slides relative to the main frame 101 in the fourth direction, the drum cartridge 2 can be attached to and detached from the main frame 101.

[0082] The four developing cartridges 1 contain developers of mutually different colors (for example: yellow, magenta, cyan, and black). The developer is, for example, toner. The image forming apparatus 100 is configured to perform printing using the developer supplied from the developing cartridge 1 to form an image on the surface of the printing sheet.

[0083] <2. Structure of the developing cartridge>

[0084] Figure 2 and Figure 3 are perspective views of the developing cartridge 1. Figure 4 is a front view of the developing cartridge 1 (viewed along the fourth direction). Figure 5 A cross-sectional view of the developing cartridge 1 along the line V-V of Figure 4 . As Figures 2 to 5 shown, the developing cartridge 1 includes a housing 10, a stirrer 20, a developing roller 30, a supply roller 35, a gear portion 40, a storage assembly 50, and a separating member 60.

[0085] <2-1. Housing>

[0086] The housing 10 is a container configured to accommodate a developer. The housing 10 has a first outer surface 11 and a second outer surface 12. The first outer surface 11 is located at one end of the housing 10 in the first direction. The second outer surface 12 is located at the other end of the housing 10 in the first direction. The first outer surface 11 and the second outer surface 12 are separated from each other in the first direction.

[0087] A storage chamber 13 is formed in the housing 10. The developer is stored in the storage chamber 13. The housing 10 also has an opening 14. The opening 14 is located at one end of the housing 10 in the second direction. The storage chamber 13 and the external space of the housing 10 communicate with each other via the opening 14.

[0088] The housing 10 includes a first frame 15 and a second frame 16. The first frame 15 and the second frame 16 extend in the first direction. The first frame 15 and the second frame 16 are arranged in the fourth direction. The first frame 15 has a substantially cup-shaped configuration. Specifically, the first frame 15 is recessed away from the second frame 16 in the fourth direction. The second frame 16 has a substantially plate-shaped configuration. The first frame 15 and the second frame 16 are fixed to each other. The storage chamber 13 is a space surrounded by the first frame 15 and the second frame 16.

[0089] <2-2. Agitator>

[0090] The agitator 20 is configured to agitate toner in the housing 10. As Figure 5 shown, the agitator 20 includes an agitation shaft 21 and agitation vanes 22. The agitation shaft 21 extends in the first direction within the housing 10. The agitation shaft 21 is supported by the housing 10, and the agitation shaft 21 is capable of rotating about an agitator axis extending in the first direction. The agitation vanes 22 extend radially outward from the agitation shaft 21.

[0091] <2-3. Developing roller>

[0092] The developing roller 30 is capable of rotating about a developing axis (rotation axis) extending in the first direction. The developing roller 30 is located at the opening 14 of the housing 10. That is, the developing roller 30 is located at one end of the housing 10 in the second direction.

[0093] The developing roller 30 includes a developing roller body 31 and a developing roller shaft 32. The developing roller body 31 is a hollow cylindrical member extending in the first direction. The developing roller body 31 is made of, for example, elastic rubber. The developing roller shaft 32 is a solid cylindrical member extending in the first direction and penetrates the developing roller body 31. The developing roller body 31 is fixed to the developing roller shaft 32. The developing roller shaft 32 is made of metal or conductive resin.

[0094] The developing roller 30 is supported by the first frame 15. The developing roller shaft 32 has an end portion in the first direction, and this end portion is supported by the end portion of the first frame 15 in the first direction via a bearing. The developing roller shaft 32 also has an end portion in the first direction, and this end portion is supported by the end portion of the first frame 15 in the first direction via a bearing. By using the driving force supplied from the image forming apparatus 100, the developing roller 30 can rotate around the developing axis. The developer in the housing 10 is held on the outer peripheral surface of the developing roller 30 (i.e., the outer peripheral surface of the developing roller main body 31).

[0095] <2-4. Supply roller>

[0096] The supply roller 35 can rotate around the supply axis extending in the first direction. The supply roller 35 is located inside the housing 10. Specifically, the supply roller 35 is located between the developing roller 30 and the agitator 20 in the second direction.

[0097] The supply roller 35 includes a supply roller main body 36 and a supply roller shaft 37. The supply roller main body 36 is a hollow cylindrical member extending in the first direction. The supply roller main body 36 is made of, for example, elastic rubber. The outer peripheral surface of the supply roller main body 36 is in contact with the outer peripheral surface of the developing roller main body 31. The supply roller shaft 37 is a solid cylindrical member extending in the first direction and penetrates the supply roller main body 36. The supply roller main body 36 is fixed to the supply roller shaft 37.

[0098] <2-5. Gear portion>

[0099] The gear portion 40 is located on the first outer surface 11 of the housing 10. As Figures 2 to 4 shown, the gear portion 40 includes a gear cover 41, and this gear cover 41 is attached to the first outer surface 11 of the housing 10. Figure 6 Figure 1 shows the developing cartridge 1 in a state where the gear cover 41 is removed, viewed in the first direction and in the direction from the first outer surface 11 toward the second outer surface 12. Figure 7 is a partial perspective view of the developing cartridge 1 in a state where the gear cover 41 is removed. Figure 8 Figure 2 shows the developing cartridge 1 in a state where the gear cover 41 is removed, viewed in the fourth direction and in the direction from the first frame 15 toward the second frame 16, and particularly shows a portion near the first outer surface 11.

[0100] As Figures 6 to 8As shown, the gear unit 40 further includes a coupling 42, a coupling gear 43, a supply roller gear 44, a first idle gear 45, a developing roller gear 46, a second idle gear 47, and a stirrer gear 48. The coupling gear 43, the supply roller gear 44, the first idle gear 45, the developing roller gear 46, the second idle gear 47, and the stirrer gear 48 are located between the first outer surface 11 and the gear cover 41 in the first direction. That is, the coupling gear 43, the supply roller gear 44, the first idle gear 45, the developing roller gear 46, the second idle gear 47, and the stirrer gear 48 are covered by the gear cover 41.

[0101] The coupling 42, the coupling gear 43, the supply roller gear 44, the first idle gear 45, the developing roller gear 46, the second idle gear 47, and the stirrer gear 48 can rotate about their axes along the first direction.

[0102] The coupling 42 is exposed to the outside via the gear cover 41. When the drum cartridge 2 with the developing cartridge 1 attached is attached to the main frame 101, the drive shaft of the image forming apparatus 100 is connected to the coupling 42 of the corresponding developing cartridge 1, whereby the rotation of the drive shaft is transmitted to the coupling 42. The coupling gear 43 rotates together with the coupling 42.

[0103] The coupling gear 43 meshes with the supply roller gear 44. The supply roller gear 44 meshes with the first idle gear 45. The first idle gear 45 meshes with the developing roller gear 46. In addition, the coupling 42 also meshes with the second idle gear 47. The second idle gear 47 meshes with the stirrer gear 48.

[0104] The supply roller gear 44 is connected to one end of the supply roller shaft 37 in the first direction. Therefore, the rotation of the coupling 42 is transmitted to the supply roller shaft 37 via the coupling gear 43 and the supply roller gear 44. Thereby, the supply roller 35 rotates about the supply shaft.

[0105] The developing roller gear 46 is connected to one end of the developing roller shaft 32 in the first direction. Thereby, the rotation of the coupling 42 is transmitted to the developing roller shaft 32 via the coupling gear 43, the supply roller gear 44, the first idle gear 45, and the developing roller gear 46, so that the developing roller 30 rotates about the developing shaft.

[0106] The stirrer gear 48 is connected to one end of the stirrer shaft 21 in the first direction. Therefore, the rotation of the coupling 42 is transmitted to the stirrer shaft 21 via the coupling gear 43, the second idle gear 47, and the stirrer gear 48. Thereby, the stirrer 20 rotates about the stirrer shaft, thereby stirring the developer in the stirrer housing 10.

[0107] As Figure 8As shown, a part of the coupling gear 43, the supply roller gear 44, the first idle gear 45, the developing roller gear 46, a part of the second idle gear 47, and the agitator gear 48 are located within the region R in the first direction. Compared with the configuration in which these gears are located at different positions from each other in the first direction, this structure makes the gear unit 40 thinner in the first direction.

[0108] Here, each of the coupling gear 43 and the second idle gear 47 has a larger dimension in the first direction than the other gears. The coupling gear 43 is a two-stage gear. Therefore, the coupling gear 43 can transmit rotation to the supply roller gear 44 and the second idle gear 47 at different rotational speeds. In addition, the second idle gear 47 is a two-stage gear. With this structure, the rotational speed can be changed when the rotation is transmitted from the coupling gear 43 via the second idle gear 47 to the agitator gear 48.

[0109] As Figures 6 to 8 shown, the first frame 15 has a filling port 153 and includes a lid 154 for closing the filling port 153. The filling port 153 is located at one end of the first frame 15 in the first direction. In addition, the filling port 153 is located in the second direction at a position where the filling port 153 is farther from the developing roller 30 than the agitator gear 48 is from the developing roller 30. The developer is supplied to the storage chamber 13 of the housing 10 via the filling port 153.

[0110] In addition, as Figure 8 shown, the filling port 153 protrudes more outward in the first direction than the region R. That is, the filling port 153 is located more outside the housing 10 in the first direction than the supply roller gear 44, the first idle gear 45, the developing roller gear 46, and the agitator gear 48.

[0111] <2-6. Storage Component>

[0112] The storage component 50 is located on the second outer surface 12 of the housing 10. As Figure 3 and Figure 4 shown, the storage component 50 includes a memory 51, a holder 52, and a holder cover 53.

[0113] The memory 51 is a storage medium configured to store information related to the developing cartridge 1. The memory 51 is, for example, an IC chip. The memory 51 stores information related to the specifications or service life of the developing cartridge 1, for example. The memory 51 has an electrical contact surface 511. The electrical contact surface 511 is in electrical contact with the storage elements of the memory 51. The electrical contact surface 511 is located at one end of the holder 52 in the fourth direction. In the present embodiment, the memory 51 is held at one end of the holder 52 in the fourth direction. Alternatively, only the electrical contact surface 511 can be held in the holder 52, and the storage elements of the memory 51 can be held in a part of the developing cartridge 1 other than the holder 52.

[0114] The retainer cover 53 is attached to the second outer surface 12 of the housing 10. At least a part of the retainer 52 is covered by the retainer cover 53. The retainer 52 is located between the second outer surface 12 and the retainer cover 53 in the first direction. The retainer 52 is movable relative to the housing 10 and the retainer cover 53 in the first direction, the second direction, and the fourth direction. Accordingly, the electrical contact surface 511 of the memory 51 is also movable relative to the housing 10 and the retainer cover 53 in the first direction, the second direction, and the fourth direction.

[0115] <2-7. Separation member and return spring>

[0116] In a state where the drum cartridge 2 to which four developing cartridges 1 are attached is attached to the main frame 101, the image forming apparatus 100 can perform a separation operation on each developing cartridge 1. The separation operation is an operation of moving the developing roller 30 from the contact position where the developing roller 30 is in contact with the corresponding photosensitive drum 70 to the separation position where the developing roller 30 is separated from the corresponding photosensitive drum 70 with respect to the photosensitive drum 70. In the image forming apparatus 100, a separation operation is performed on the unused developing cartridge 1 among the four developing cartridges 1. By this operation, the developing roller 30 of the unused developing cartridge 1 can be separated from the corresponding photosensitive drum 70.

[0117] The separation member 60 is configured to switch the position of the developing roller 30 between the above-described contact position and separation position. That is, by the separation member 60, the developing cartridge 1 can be switched between a state where the developing roller 30 is located at the contact position and a state where the developing roller 30 is located at the separation position.

[0118] The separation member 60 is located between one end portion and the other end portion of the housing 10 in the second direction. As Figures 2 to 4 shown, the separation member 60 includes a first cam 61, a second cam 62, and a separation shaft lever 63. The separation member 60 is made of resin, for example. Specifically, the first cam 61, the second cam 62, and the separation shaft lever 63 are integrally formed by resin molding. As a modification, the first cam 61, the second cam 62, and the separation shaft lever 63 may be formed independently of each other. In the latter case, only the first cam 61 and the second cam 62 may be made of resin, and the separation shaft lever 63 may be made of metal.

[0119] Figure 9 is a partial perspective view of the developing cartridge 1 in a state where the gear cover 41 and the separation member 60 are removed. Figure 10 is another partial perspective view of the developing cartridge 1 in a state where the storage component 50 and the separation member 60 are removed. As Figure 9 and Figure 10 shown, the housing 10 further has a guide groove 19. The guide groove 19 is a groove recessed along the fourth direction on the outer surface of the second frame 16. The guide groove 19 extends in the first direction.

[0120] As Figure 2 shown, the gear cover 41 has a gear cover hole 410. The gear cover hole 410 penetrates the gear cover 41 in the first direction at a position overlapping with the guide groove 19 when viewed from the first direction. At the same time, as Figure 3 shown, the retainer cover 53 has a retainer cover hole 530. The retainer cover hole 530 penetrates the retainer cover 53 in the first direction at a position overlapping with the guide groove 19 when viewed from the first direction.

[0121] The separation shaft rod 63 is located in the guide groove 19 and extends in the first direction along the guide groove 19. The separation shaft rod 63 has an end portion in the first direction, and this end portion is inserted into the gear cover hole 410. Therefore, the end portion of the separation shaft rod 63 in the first direction is supported by the gear cover 41. The separation shaft rod 63 also has an end portion in the first direction, and this end portion is inserted into the retainer cover hole 530. Therefore, the end portion of the separation shaft rod 63 in the first direction is supported by the retainer cover 53.

[0122] As Figures 2 to 4 shown, the housing 10 further includes a first rib 191 and a second rib 192. The first rib 191 and the second rib 192 are located on the outer surface of the second frame 16 and are located at the center of the housing 10 in the first direction. The guide groove 19 has an end edge portion and the other end edge portion in the second direction. The first rib 191 projects from the center in the first direction of one end edge portion of the guide groove 19 toward the other end edge portion of the guide groove 19. The second rib 192 projects from the center in the first direction of the other end edge portion of the guide groove 19 toward one end edge portion of the guide groove 19. The first rib 191 and the second rib 192 are separated from each other in the second direction.

[0123] Each of the first rib 191 and the second rib 192 covers the portion of the separation shaft rod 63 located in the guide groove 19. Therefore, it is possible to suppress the flexure of the separation shaft rod 63 toward the outside of the housing 10 in the fourth direction. Specifically, the separation shaft rod 63 includes a small-diameter portion 631, and this small-diameter portion 631 is located at the center of the separation shaft rod 63 in the first direction. The small-diameter portion 631 has a thickness smaller than the remaining portion of the separation shaft rod 63. In other words, the small-diameter portion 631 has a diameter smaller than the remaining portion of the separation shaft rod 63. Each of the first rib 191 and the second rib 192 covers the small-diameter portion 631. This structure can suppress the first rib 191 and the second rib 192 from protruding outward from the outer surface of the second frame 16.

[0124] In addition, the small-diameter portion 631 of the separation shaft rod 63 is located between the first rib 191 and the second rib 192 in the second direction. This configuration can suppress the flexure of the center of the separation shaft rod 63 in the first direction in the second direction.

[0125] The first cam 61 is located at one end of the separating member 60 in the first direction. The first cam 61 is located on the first outer surface 11 of the housing 10. The first cam 61 has a first inclined surface 611. The first inclined surface 611 is a part of the circumferential surface centered on the separating shaft rod 63. The first inclined surface 611 is inclined with respect to the first direction. Specifically, the first inclined surface 611 is inclined in such a manner that the first inclined surface 611 moves away from the developing roller 30 in the second direction as it extends toward the other end of the separating member 60 in the first direction.

[0126] The second cam 62 is located at the other end of the separating member 60 in the first direction. The second cam 62 is located on the second outer surface 12 of the housing 10. The second cam 62 has a second inclined surface 621. The second inclined surface 621 is a part of the circumferential surface centered on the separating shaft rod 63. The second inclined surface 621 is inclined with respect to the first direction. Specifically, the second inclined surface 621 is inclined in such a manner that the second inclined surface 621 moves away from the developing roller 30 in the second direction as it extends toward the other end of the separating member 60 in the first direction.

[0127] As Figures 2 to 4 and Figure 8 shown, the separating member 60 further includes a positioning protrusion 64 as an example of a protrusion. The positioning protrusion 64 is located at one end of the separating member 60 in the first direction. The positioning protrusion 64 protrudes outward from the first cam 61 along the radial direction of the separating shaft rod 63. Specifically, the positioning protrusion 64 protrudes from the first cam 61 in the direction approaching the developing roller 30 in the second direction. In a state where the developing cartridge 1 is attached to the drum cartridge 2, the positioning protrusion 64 contacts the inner surface of the corresponding first side member 83 of the drum cartridge 2 (see Figure 13 and Figure 14 described later) in the first direction, thereby realizing the positioning of the separating member 60 relative to the first side member 83 in the first direction.

[0128] The separating member 60 is capable of moving between a first position and a second position relative to the housing 10 and the developing roller 30 in the first direction. The first position is the position of the separating member 60 in the first direction when the positioning protrusion 64 contacts the first side member 83. The movement of the separating member 60 from the first position to the second position represents the movement in the direction from the first cam 61 toward the second cam 62. That is, as a result of the separating member 60 in the first position in the first direction moving toward the other end of the separating member 60 in the first direction, the separating member 60 is located at the second position.

[0129] The separating member 60 further includes a spring seat 65 (see Figure 7 ). The spring seat 65 is located at one end of the separating member 60 in the first direction. The spring seat 65 extends from the first cam 61 in the second direction away from the first inclined surface 611.

[0130] The developing cartridge 1 further includes a return spring 66 (see Figure 7 ). The return spring 66 is an elastic member configured to expand and contract in the first direction. The return spring 66 is covered by the gear cover 41. For example, a compression coil spring is used as the return spring 66. Among one end portion and the other end portion of the housing 10 in the first direction, the return spring 66 is only located at one end portion of the housing 10 in the first direction. The return spring 66 is separated from the outer peripheral surface of the separation shaft lever 63 and is further located at a position radially outside. The return spring 66 has one end portion in the first direction and the other end portion in the first direction. This one end portion contacts the spring seat 65, and this other end portion contacts the housing 10. Specifically, the other end portion of the return spring 66 in the first direction contacts the first frame 15.

[0131] The return spring 66 is compressed in the first direction to have a length smaller than its natural length. Therefore, the return spring 66 applies a force to the separation member 60 in the direction from the second position toward the first position in the first direction. In other words, the return spring 66 applies a force to the separation member 60 in the direction from the second cam 62 toward the first cam 61. Due to the force applied by the return spring 66, the separation member 60 is located at the first position in a state where it is not pressed by the pressing lever 102 (described later, see Figure 16 ).

[0132] As Figure 7 shown, the separation shaft lever 63 has a recess 632. The recess 632 is located at one end portion of the separation shaft lever 63 in the first direction. The recess 632 is located at a position juxtaposed with the first inclined surface 611 in the first direction. The recess 632 is located at a position where the recess 632 is closer to the other end portion of the separation member 60 in the first direction than the first inclined surface 611 is to the other end portion of the separation member 60 in the first direction. In addition, the recess 632 is located between the first inclined surface 611 and the first developing guide roller 17 (described later) in the first direction. The recess 632 is recessed away from the developing roller 30 in the second direction. Thereby, contact between the separation shaft lever 63 and the first side member 83 (described later) of the drum cartridge 2 can be suppressed.

[0133] <2-8. Developing guide roller>

[0134] Figure 11 is a cross-sectional view of the developing cartridge 1 taken along the line XI-XI of Figure 4 . As Figure 9 and Figure 11As shown, the first frame 15 of the housing 10 further includes a first developing guide roller 17. The first developing guide roller 17 is located at one end of the first frame 15 in the first direction. Note that the first developing guide roller 17 is located at a position closer to the other end of the separating member 60 in the first direction than the other end of the return spring 66 in the first direction from the separating member 60.

[0135] The first developing guide roller 17 is rotatable about a first axis extending in the third direction. The first developing guide roller 17 has a hollow cylindrical outer peripheral surface centered on the first axis. The outer peripheral surface of the first developing guide roller 17 faces the separating shaft 63 in the second direction and is in contact with the separating shaft 63. The first developing guide roller 17 is rotatable about the first axis in response to the movement of the separating shaft 63 in the first direction.

[0136] As Figure 11 shown, the first frame 15 further has a first support groove 151 recessed in the third direction. The first support groove 151 supports one end of the first developing guide roller 17 in the third direction. Specifically, one end of the first developing guide roller 17 in the third direction is inserted into the first support groove 151. Thus, the first developing guide roller 17 is supported by the first frame 15 and is rotatable about the first axis.

[0137] Figure 12 is a cross-sectional view of the developing cartridge 1 taken along the Figure 4 line XII-XII. As Figure 10 and Figure 12 shown, the first frame 15 of the housing 10 further includes a second developing guide roller 18. The second developing guide roller 18 is located at the other end of the first frame 15 in the first direction. That is, the first developing guide roller 17 and the second developing guide roller 18 are separated from each other in the first direction.

[0138] The second developing guide roller 18 is rotatable about a second axis extending in the third direction. The second developing guide roller 18 has a hollow cylindrical outer peripheral surface centered on the second axis. The outer peripheral surface of the second developing guide roller 18 faces the separating shaft 63 in the second direction and is in contact with the separating shaft 63. The second developing guide roller 18 is rotatable about the second axis in response to the movement of the separating shaft 63 in the first direction.

[0139] As Figure 12 shown, the first frame 15 further has a second support groove 152 recessed in the third direction. The second support groove 152 supports one end of the second developing guide roller 18 in the third direction. Specifically, one end of the second developing guide roller 18 in the third direction is inserted into the second support groove 152. Therefore, the second developing guide roller 18 is supported by the first frame 15 and is rotatable about the second axis.

[0140] <3. Structure of the drum cartridge>

[0141] Figure 13 is a perspective view of the drum cartridge 2. As Figure 13 shown, the drum cartridge 2 includes four photosensitive drums 70, four drum frames 80, a first metal plate 81, a second metal plate 82, four first side members 83, and four second side members 84.

[0142] <3-1. Photosensitive drum>

[0143] The photosensitive drums 70 are located at one end of the drum cartridge 2 in the second direction. The four photosensitive drums 70 respectively correspond to four developers of different colors (for example, yellow, magenta, cyan, and black). The four photosensitive drums 70 are arranged in the fourth direction in the order of, for example, the photosensitive drum 70 corresponding to yellow, the photosensitive drum 70 corresponding to magenta, the photosensitive drum 70 corresponding to cyan, and the photosensitive drum 70 corresponding to black. The photosensitive drum 70 corresponding to yellow and the photosensitive drum 70 corresponding to magenta are arranged separately from each other in the fourth direction. The photosensitive drum 70 corresponding to magenta and the photosensitive drum 70 corresponding to cyan are arranged separately from each other in the fourth direction. The photosensitive drum 70 corresponding to cyan and the photosensitive drum 70 corresponding to black are arranged separately from each other in the fourth direction.

[0144] Each photosensitive drum 70 is supported by a corresponding one of the drum frames 80 and is rotatable about a drum axis extending in the first direction. The photosensitive drum 70 has a hollow cylindrical outer peripheral surface centered on the drum axis. The outer peripheral surface of the photosensitive drum 70 is coated with a photosensitive material. When the developing cartridge 1 is attached to the drum cartridge 2, the outer peripheral surface of the developing roller 30 contacts the outer peripheral surface of the corresponding photosensitive drum 70.

[0145] <3-2. Drum frame>

[0146] Each drum frame 80 supports the corresponding photosensitive drum 70. The four drum frames 80 are arranged in the fourth direction. Among the four drum frames 80, two adjacent drum frames 80 are arranged separately from each other in the fourth direction. The drum frames 80 extend in the first direction between the first metal plate 81 and the second metal plate 82. The photosensitive drum 70 has one end in the first direction, and this end is supported by one end of the corresponding drum frame 80 in the first direction via a bearing. The photosensitive drum 70 also has the other end in the first direction, and this end is supported by the other end of the corresponding drum frame 80 in the first direction via a bearing. The developing cartridge 1 can be attached to the drum frame 80.

[0147] <3-3. Metal plate>

[0148] The first metal plate 81 supports one end portion of the drum frame body 80 in the first direction. The first metal plate 81 has a substantially plate-like shape extending in both the second direction and the fourth direction. The first metal plate 81 is made of a metal such as iron or stainless steel. The rigidity of the first metal plate 81 is higher than that of the drum frame body 80 and the first side member 83. The first metal plate 81 covers one end portion of the four drum frame bodies 80 in the first direction. One end portion of the drum frame body 80 in the first direction is fixed to the first metal plate 81.

[0149] In addition, the drum cartridge 2 includes a first side plate (not shown). The first side plate covers the outer surface of the first metal plate 81. The first side plate is fixed to the first metal plate 81.

[0150] The second metal plate 82 supports the other end portion of the drum frame body 80 in the first direction. The second metal plate 82 has a substantially plate-like shape extending in both the second direction and the fourth direction. The second metal plate 82 is made of a metal such as iron or stainless steel. The rigidity of the second metal plate 82 is higher than that of the drum frame body 80 and the second side member 84. The second metal plate 82 covers the other end portion of the four drum frame bodies 80 in the first direction. The other end portion of the drum frame body 80 in the first direction is fixed to the second metal plate 82.

[0151] The drum cartridge 2 further includes a second side plate (not shown). The second side plate covers the outer surface of the second metal plate 82. The second side plate is fixed to the second metal plate 82.

[0152] The four photosensitive drums 70 are located between the first metal plate 81 and the second metal plate 82 in the first direction. In addition, in a state where the developing cartridge 1 is attached to the drum cartridge 2, the housing 10 of the developing cartridge 1 is located between the first metal plate 81 and the second metal plate 82 in the first direction.

[0153] <3-4. Side members>

[0154] The four first side members 83 are located at one end portion of the drum cartridge 2 in the first direction. The four first side members 83 are arranged in the fourth direction. Each first side member 83 is fixed to the inner surface of the first metal plate 81. Specifically, each first side member 83 is fixed to the first metal plate 81 by a threaded member. Since the first side member 83 is fixed to the first metal plate 81 having a higher rigidity than the first side member 83, displacement of the first side member 83 can be suppressed.

[0155] Figure 14 Yes Figure 13 is an enlarged view of region D in. As Figure 14As shown, the first side member 83 includes a first plate portion 831. The first plate portion 831 extends from the first side member 83 in a fourth direction toward an adjacent first side member 83. The first plate portion 831 has a distal end portion in the fourth direction, and this distal end portion is inserted between the adjacent first side member 83 and the first metal plate 81. With this structure, deformation of the first side member 83 can be suppressed. The first plate portion 831 and the adjacent first side member 83 are fixed to the first metal plate 81 by a common threaded member.

[0156] Here, in a first direction, a gap is formed between the first plate portion 831 and the adjacent first side member 83. Further, in the first direction, a gap is formed between the first plate portion 831 and the first metal plate 81. Therefore, expansion and contraction of the first side member 83 due to temperature changes are allowed.

[0157] In addition, as Figure 14 shown, the first side member 83 further includes a first drum guide roller 85. The first drum guide roller 85 is rotatable about an axis extending in a third direction. In a state where the developing cartridge 1 is attached to the drum cartridge 2, the first drum guide roller 85 is located more outward in the first direction than the first developing guide roller 17. When the separating member 60 moves from a first position to a second position in a state where the developing cartridge 1 is attached to the drum cartridge 2, the first inclined surface 611 of the first cam 61 contacts the first drum guide roller 85. Therefore, in the present embodiment, the outer surface of the first drum guide roller 85 is an example of a "first contact surface". That is, in the present embodiment, the outer surface of the first drum guide roller 85 is an example of a "contact surface", and when the separating member 60 moves from a first position to a second position in a state where the developing cartridge 1 is attached to the drum cartridge 2, this "contact surface" contacts the separating member 60.

[0158] Four second side members 84 are located at the other end portion of the drum cartridge 2 in the first direction. The four second side members 84 are arranged in the fourth direction. Each second side member 84 is fixed to the inner surface of the second metal plate 82. Specifically, each second side member 84 is fixed to the second metal plate 82 by a threaded member. Since the second side member 84 is fixed to the second metal plate 82 having higher rigidity than the second side member 84, displacement of the second side member 84 can be suppressed.

[0159] Figure 15 is Figure 13 an enlarged view of region E in Figure 15As shown, the second side member 84 includes a second plate-like portion 841. The second plate-like portion 841 extends from the second side member 84 in a fourth direction toward an adjacent second side member 84. The second plate-like portion 841 has a distal end portion in the fourth direction, and this distal end portion is inserted between the adjacent second side member 84 and the second metal plate 82. Therefore, deformation of the second side member 84 can be suppressed. The second plate-like portion 841 and the adjacent second side member 84 are fixed to the second metal plate 82 by a common threaded member.

[0160] In a first direction, a gap is formed between the second plate-like portion 841 and the adjacent second side member 84. Additionally, in the first direction, a gap is formed between the second plate-like portion 841 and the second metal plate 82. Thereby, expansion and contraction of the second side member 84 due to temperature changes are allowed.

[0161] In addition, as Figure 15 shown, the second side member 84 further includes a second drum guide roller 86. The second drum guide roller 86 can rotate about an axis extending in a third direction. The first drum guide roller 85 and the second drum guide roller 86 are separated from each other in the first direction. In a state where the developing cartridge 1 is attached to the drum cartridge 2, the second drum guide roller 86 is located more outward in the first direction than the second developing guide roller 18. When the separating member 60 moves from a first position to a second position in a state where the developing cartridge 1 is attached to the drum cartridge 2, the second inclined surface 621 of the second cam 62 contacts the second drum guide roller 86. Therefore, in the present embodiment, the outer surface of the second drum guide roller 86 is an example of the "second contact surface". That is, in the present embodiment, the outer surface of the second drum guide roller 86 is also an example of the "contact surface", and when the separating member 60 moves from the first position to the second position in a state where the developing cartridge 1 is attached to the drum cartridge 2, this "contact surface" contacts the separating member 60.

[0162] As Figure 14 shown, the first side member 83 further includes a first developing pressing portion 87. The first developing pressing portion 87 includes an elastic member such as a spring. As Figure 15 shown, the second side member 84 further includes a second developing pressing portion 88. The second developing pressing portion 88 includes an elastic member such as a spring.

[0163] When the developing cartridge 1 is attached to the drum cartridge 2, the first developing pressing portion 87 and the second developing pressing portion 88 contact the first frame 15 of the developing cartridge 1. In this state, the first developing pressing portion 87 and the second developing pressing portion 88 apply a force to the developing cartridge 1 in a second direction toward the photosensitive drum 70, whereby the developing roller 30 contacts the photosensitive drum 70. That is, the developing roller 30 reaches the above-described contact position.

[0164] <4. Separation operation>

[0165] Next, the separation operation performed in the image forming apparatus 100 will be described. Figure 16 and 17 are cross-sectional views of the drum cartridge 2 to which the developing cartridge 1 is attached, including the separation member 60. Figure 16 It shows a state where the separation member 60 is in the first position and the separation operation is not performed. Figure 17 It shows a state where the separation member 60 is in the second position and the separation operation has been performed.

[0166] As Figure 16 and 17 shown, the image forming apparatus 100 includes a pressing shaft rod 102. In a state where the drum cartridge 2 to which four developing cartridges 1 are attached is attached to the main frame 101, each pressing shaft rod 102 faces the first cam 61 of the corresponding developing cartridge 1.

[0167] The pressing shaft rod 102 can move in the first direction between a retracted position ( Figure 16 the position shown) and a protruding position ( Figure 17 the position shown). The pressing shaft rod 102 in the protruding position is closer to the developing cartridge 1 than the pressing shaft rod 102 in the retracted position. In order to perform the separation operation in the image forming apparatus 100, the pressing shaft rod 102 moves from the retracted position to the protruding position and contacts the first cam 61. The pressing shaft rod 102 presses the separation member 60 in the direction from the first cam 61 to the second cam 62 in the first direction. Therefore, the return spring 66 is compressed, and thereby the separation member 60 moves in the first direction relative to the housing 10 from the first position to the second position.

[0168] As the separation member 60 moves from the first position to the second position, the first inclined surface 611 of the first cam 61 moves in the first direction while the first inclined surface 611 maintains contact with the first drum guide roller 85 of the drum cartridge 2. The first drum guide roller 85 rotates according to the movement of the first inclined surface 611 in the first direction. At this time, due to the reaction force from the first drum guide roller 85, the first cam 61 moves in the second direction relative to the drum cartridge 2. Specifically, by the reaction force applied from the first drum guide roller 85, the first cam 61 moves relative to the drum cartridge 2 in a direction away from the photosensitive drum 70.

[0169] Similarly, according to the movement of the separating member 60 from the first position to the second position, the second inclined surface 621 of the second cam 62 moves in the first direction while the second inclined surface 621 remains in contact with the second drum guide roller 86 of the drum cartridge 2. The second drum guide roller 86 rotates according to the movement of the second inclined surface 621 in the first direction. At this time, due to the reaction force from the second drum guide roller 86, the second cam 62 moves relative to the drum cartridge 2 in the second direction. Specifically, due to the reaction force applied from the second drum guide roller 86, the second cam 62 moves relative to the drum cartridge 2 in a direction away from the photosensitive drum 70.

[0170] In this way, the housing 10 and the developing roller 30 move relative to the drum cartridge 2 in the second direction together with the separating member 60. Specifically, the housing 10 and the developing roller 30 move relative to the drum cartridge 2 in a direction away from the photosensitive drum 70. As a result, the developing roller 30 moves in the second direction from the contact position where the developing roller 30 is in contact with the photosensitive drum 70 to the separation position where the developing roller 30 is separated from the photosensitive drum 70.

[0171] The separating shaft rod 63 is in contact with the first developing guide roller 17 and the second developing guide roller 18. Therefore, during the separating operation, the first developing guide roller 17 and the second developing guide roller 18 receive a load in the second direction from the separating shaft rod 63. In this way, in the present embodiment, the outer surface (outer circumferential surface) of the first developing guide roller 17 and the outer surface (outer circumferential surface) of the second developing guide roller 18 serve as a "load-bearing surface", and this "load-bearing surface" is configured to receive a load in the second direction from the separating shaft rod 63.

[0172] With this structure, among the first frame 15 and the second frame 16 constituting the housing 10, the first frame 15 that supports the developing roller 30 includes the first developing guide roller 17 and the second developing guide roller 18. Therefore, during the separating operation, the first frame 15 that supports the developing roller 30 receives a load in the second direction from the separating shaft rod 63. This structure allows the developing roller 30 to move precisely relative to the drum cartridge 2 in the second direction regardless of the fixing accuracy of the first frame 15 and the second frame 16 and the dimensional accuracy of the second frame 16.

[0173] Even if the first frame 15 and the second frame 16 are fixed to each other with high precision, there is still a slight looseness between the first frame 15 and the second frame 16. Moreover, even if the second frame 16 is precisely formed, the second frame 16 still has a slight dimensional tolerance. Assume that the separating shaft rod 63 presses the second frame 16 during the separating operation, then the movement of the separating shaft rod 63 in the second direction is transmitted to the developing roller 30 through the second frame 16 and the first frame 15. In this case, the amount of movement of the developing roller 30 may vary based on the above looseness and dimensional tolerance.

[0174] In contrast, since the separation shaft rod 63 presses the first frame 15 during the separation operation as described above, the movement of the separation shaft rod 63 in the second direction is transmitted to the developing roller 30 through the first frame 15 without the intervention of the second frame 16. As a result, the amount of movement of the developing roller 30 is not affected by the above-mentioned looseness and dimensional tolerances, so that the developing roller 30 can move precisely in the second direction relative to the drum cartridge 2.

[0175] In particular, according to the present embodiment, the outer surface of the first developing guide roller 17 acting as a "load-bearing surface" rotates in response to the movement of the separation shaft rod 63 in the first direction, and the outer surface of the second developing guide roller 18 also acting as a "load-bearing surface" rotates in response to the movement of the separation shaft rod 63 in the first direction. With this structure, the frictional resistance generated due to the movement of the separation shaft rod 63 relative to the first frame 15 can be reduced, thereby enabling the separation shaft rod 63 to move precisely in the first direction relative to the housing 10.

[0176] In addition, the load in the second direction from the separation shaft rod 63 is borne by two parts, namely the first developing guide roller 17 and the second developing guide roller 18 that are separated from each other in the first direction. Therefore, the developing roller 30 can move precisely relative to the photosensitive drum 70, and the inclination of the developing cartridge 1 relative to the drum cartridge 2 is suppressed.

[0177] <5. Modification Example>

[0178] Although the present invention has been described in connection with various exemplary structures outlined above and illustrated in the accompanying drawings, various alternatives, modifications, variations, improvements, and / or substantial equivalents, whether known or currently unforeseeable, will be apparent to those skilled in the art. Therefore, the exemplary structural modes of the present disclosure as described above are intended to illustrate the present invention rather than limit the present invention. Various changes can be made without departing from the gist and scope of the present disclosure. Accordingly, the present disclosure is intended to cover all known or future-developed alternatives, modifications, variations, improvements, and / or substantial equivalents. Specific examples of some potential alternatives, modifications, or variations of the above invention are provided below:

[0179] <5-1. First Modification Example>

[0180] Figure 18Is a partial perspective view of the developing cartridge 1A according to the first modification example, and shows a state in which the gear cover 41 and the separating member 60 are omitted. The developing cartridge 1A according to the first modification example includes a housing 10A which is composed of a first frame 15A and a second frame 16, and the first frame 15A supports the developing roller 30. In the first modification example, the first frame 15A has a load bearing surface 171. The load bearing surface 171 is not the outer surface of the roller but the outer surface of the first frame 15A. The load bearing surface 171 faces the separating shaft lever 63 in the second direction. During the separating operation, the load bearing surface 171 receives a load in the second direction from the separating shaft lever 63.

[0181] Even with this structure, the first frame 15A that supports the developing roller 30 also receives a load in the second direction during the separating operation. Therefore, the developing roller 30 can move precisely in the second direction relative to the photosensitive drum 70 regardless of the fixing accuracy of the first frame 15A and the second frame 16 and the dimensional accuracy of the second frame 16.

[0182] <5-2. Second Modification Example>

[0183] In the above-described embodiment, each first side member 83 of the drum cartridge 2 includes a first drum guide roller 85, and the outer surface of the first drum guide roller 85 functions as a "first contact surface" which contacts the first cam 61 during the separating operation. Similarly, each second side member 84 of the drum cartridge 2 includes a second drum guide roller 86, and the outer surface of the second drum guide roller 86 functions as a "second contact surface" which contacts the second cam 62 during the separating operation. With this structure, the frictional resistance generated due to the movement of the separating member 60 relative to the first side member 83 and the second side member 84 can be reduced.

[0184] Alternatively, the "first contact surface" may be the outer surface of the first side member 83 instead of the outer surface of the roller. Moreover, the "second contact surface" may be the outer surface of the second side member 84 instead of the outer surface of the roller.

[0185] <5-3. Other Modification Examples>

[0186] In the above-described embodiment, the developing cartridge 1 includes a first developing guide roller 17 and a second developing guide roller 18. That is, the developing cartridge 1 has two "load bearing surfaces". However, the developing cartridge may include only one developing guide roller, or may include three or more developing guide rollers. That is, the developing cartridge 1 may have only one load bearing surface, or may have three or more load bearing surfaces.

[0187] In the above-described embodiment, the drum cartridge 2 has a first drum guide roller 85 and a second drum guide roller 86. That is, for each developing cartridge 1, the drum cartridge 2 has two "contact surfaces" that come into contact with the separating member 60 during the separating operation. However, as a modification, for each developing cartridge 1, the drum cartridge 2 may include only one drum guide roller, or may include three or more drum guide rollers. That is, for each developing cartridge 1, the drum cartridge 2 may have only one contact surface, or may have three or more contact surfaces.

[0188] In the above-described embodiment, the separating member 60 has a first inclined surface 611 and a second inclined surface 621. However, the second inclined surface 621 may be omitted.

[0189] In the above-described embodiment, the housing 10 of the developing cartridge 1 includes a first rib 191 and a second rib 192. Alternatively, the housing 10 may include only one of the first rib 191 and the second rib 192. Additionally, both the first rib 191 and the second rib 192 may be omitted from the housing 10.

[0190] In the above-described embodiment, four developing cartridges 1 can be attached to the drum cartridge 2. However, the drum cartridge 2 may also be modified to receive one to three developing cartridges 1, or five or more developing cartridges 1.

[0191] Note that the specific shapes and structures of the developing cartridge and the image forming apparatus may be appropriately changed without departing from the scope of the present disclosure. Additionally, parts and components that appear in the above-described embodiment and modification examples may be appropriately adopted or omitted as long as there is no contradiction.

[0192] Reference Signs

[0193] 1, 1A: Developing Cartridge, 2: Drum Cartridge, 10, 10A: Housing, 15, 15A: First Frame, 16: Second Frame, 17: First Developing Guide Roller, 18: Second Developing Guide Roller, 20: Agitator, 30: Developing Roller, 35: Supply Roller, 40: Gear Unit, 50: Storage Assembly, 60: Separating Member, 61: First Cam, 62: Second Cam, 63: Separation Shaft Rod, 66: Return Spring, 70: Photosensitive Drum, 83: First Lateral Member, 84: Second Lateral Member, 85: First Drum Guide Roller, 86: Second Drum Guide Roller, 87: First Developing Pressing Portion, 88: Second Developing Pressing Portion, 100: Image Forming Apparatus, 171: Load Bearing Surface, 191: First Rib, 192: Second Rib, 611: First Inclined Surface, 621: Second Inclined Surface.

Claims

1. A developing cartridge that can be attached to a drum cartridge, characterized in that, The developing cartridge includes: a developing roller that is rotatable about an axis extending in a first direction; a housing configured to contain a developer, the housing having an end portion in a second direction, the developing roller being located at the end portion of the housing, the second direction intersecting the first direction, the housing including a first frame and a second frame, the first frame supporting the developing roller and the second frame being fixed to the first frame; and a separating member that is movable relative to the housing in the first direction, the separating member including a separating shaft rod extending in the first direction and a first inclined surface located at an end portion of the separating member in the first direction, the first inclined surface extending away from the developing roller in the second direction as it extends toward the other end portion of the separating member in the first direction, wherein the first frame has a load-bearing surface that faces the separating shaft rod in the second direction, and in a state where the developing cartridge is attached to the drum cartridge, when the separating member moves in the first direction and the first inclined surface contacts the drum cartridge, the load-bearing surface contacts the separating shaft rod to receive a load in the second direction from the separating shaft rod.

2. The developing cartridge according to claim 1, wherein the first frame includes a first developing guide roller that is rotatable about an axis extending in a third direction, the third direction intersecting both the first direction and the second direction, the first developing guide roller contacting the separating shaft rod and rotating in response to movement of the separating shaft rod in the first direction, and wherein the load-bearing surface includes an outer surface of the first developing guide roller.

3. The developing cartridge according to claim 2, wherein the first frame further has a support groove that supports an end portion of the first developing guide roller in the third direction.

4. The developing cartridge according to claim 2, wherein the first frame further includes a second developing guide roller that is separated from the first developing guide roller in the first direction, the second developing guide roller being rotatable about an axis extending in the third direction, the second developing guide roller contacting the separating shaft rod and rotating in response to movement of the separating shaft rod in the first direction, and wherein the load-bearing surface further includes an outer surface of the second developing guide roller.

5. The developing cartridge according to claim 1, wherein the separating member further includes a spring seat that extends away from the first inclined surface in the second direction, the developing cartridge further includes a return spring configured to expand and contract in the first direction, the return spring having an end portion in the first direction that contacts the spring seat and an end portion in the first direction that contacts the housing.

6. The developing cartridge according to claim 5, wherein The other end portion of the return spring in the first direction contacts the first frame.

7. The developing cartridge according to claim 5, wherein the load bearing surface is located at a position where the load bearing surface is closer to the other end portion of the separating member in the first direction than the other end portion of the return spring is to the separating member in the first direction.

8. The developing cartridge according to claim 5, wherein the return spring is separated from the outer peripheral surface of the separating shaft rod and is further located at a position radially outside.

9. The developing cartridge according to claim 5, wherein the housing has one end portion and the other end portion in the first direction, and wherein, among the one end portion and the other end portion of the housing in the first direction, the return spring is only located at the one end portion of the housing in the first direction.

10. The developing cartridge according to claim 9, wherein, It further includes: a gear located at the one end portion of the housing in the first direction; and a gear cover attached to the one end portion of the housing in the first direction and covering the gear, wherein the return spring is also covered by the gear cover.

11. The developing cartridge according to claim 5, wherein the return spring is a compression coil spring.

12. The developing cartridge according to claim 1, wherein the housing further includes a rib that protrudes from the outer surface of the housing and covers a part of the separating shaft rod.

13. The developing cartridge according to claim 12, characterized in that the rib is located at the center of the housing in the first direction.

14. The developing cartridge according to claim 12, wherein the second frame includes the rib.

15. The developing cartridge according to claim 14, wherein the second frame has a guide groove that extends in the first direction, the separating shaft rod is located in the guide groove, and wherein the rib covers the part of the separating shaft rod located in the guide groove.

16. The developing cartridge according to claim 12, wherein the separating shaft rod has a small-diameter portion whose diameter is smaller than the diameter of the rest of the separating shaft rod, and wherein the rib covers the small-diameter portion.

17. The developing cartridge according to claim 12, wherein the housing includes: a first rib, which is the rib; and a second rib, which is the rib located at a position separated from the first rib in the second direction, and wherein the part of the separating shaft rod is located between the first rib and the second rib in the second direction.

18. The developing cartridge according to claim 1, wherein, It further includes: a gear located at the one end portion of the housing in the first direction; a gear cover attached to the one end portion of the housing in the first direction and covering the gear; a memory having an electrical contact surface; a holder located at the other end portion of the housing in the first direction and holding the electrical contact surface; and A retainer cover, which is attached to the other end portion of the housing in the first direction and covers at least a part of the retainer. Wherein, the separating member is supported by the gear cover and the retainer cover.

19. The developing cartridge according to claim 1, wherein: The separating shaft has a recess that is recessed away from the developing roller in the second direction, and the recess is juxtaposed with the first inclined surface in the first direction.

20. The developing cartridge according to claim 19, wherein: The recess is located at a position where the recess is closer to the other end portion of the separating member in the first direction than the first inclined surface is to the other end portion of the separating member in the first direction.

21. The developing cartridge according to claim 19, wherein: The recess is located between the load-bearing surface and the first inclined surface in the first direction.

22. The developing cartridge according to claim 1, wherein: The separating member further includes a protrusion that protrudes outward in the radial direction of the separating shaft, and in a state where the developing cartridge is attached to the drum cartridge, the protrusion contacts the drum cartridge in the first direction.

23. The developing cartridge according to claim 1, wherein: The separating shaft is made of resin.

24. The developing cartridge according to claim 1, wherein: The drum cartridge includes a photosensitive drum, and wherein, when the separating member moves in the first direction in a state where the developing cartridge is attached to the drum cartridge, the developing roller separates from the photosensitive drum in the second direction.

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