Developer Cartridge

Abstract

A developing roller (12) is closer to a first end (113) of a housing (11) in a first direction than to a second end (114) of the housing (11) in the first direction. A first protrusion (13) extends in a second direction and is movable together with the housing. When the first protrusion is supported by a support surface (41) of a first side plate (33) of a drum unit (3), the first protrusion bears the weight of a developing cartridge (1), and it is away from the developing roller in the first direction and a third direction. A first pressure receiving surface (15) is farther from the developing roller in the third direction than the first protrusion is from the developing roller. The first pressure receiving surface receives a pressing force in the third direction from a pressing member (47) of the first side plate of the drum unit. The first protrusion is at a first distance (D1) from the developing roller in the first direction. The first pressure receiving surface is at the first distance or a second distance (D2) less than the first distance from the developing roller in the first direction.

Description

[0001] This application is a divisional application of the following patent application:

[0002] Application No.: 201880003652.7

[0003] Filing Date: September 28, 2018

[0004] Title of Invention: Developer Cartridge Technical Field

[0005] The present disclosure relates to a developer cartridge. Background Art

[0006] Known electrophotographic image forming apparatuses in the prior art include laser printers and light emitting diode (LED) printers. For example, Patent Document 1 discloses an image forming apparatus including a developer cartridge and a drum unit. The drum unit includes a plurality of photosensitive drums. The developer cartridge is attachable to and removable from the drum unit. When the developer cartridge is attached to the drum unit, a developing roller of the developer cartridge contacts a corresponding photosensitive drum of the drum unit.

[0007] Each developer cartridge includes a developing roller shaft that rotates together with the developing roller. When the developer cartridge is attached to the drum unit, the developer cartridge rotates relative to the drum unit about the developing roller shaft due to the weight of the developer cartridge. Then, the developer cartridge is positioned relative to the drum unit.

[0008] [Citation List]

[0009] [Patent Document]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2007-101635 Summary of the Invention

[0011] [Technical Problem]

[0012] When the developer cartridge is attached to the drum unit, the developer cartridge pivots relative to the drum unit about the developing roller shaft. Depending on the remaining amount of toner in the developer cartridge, the developing roller of the developer cartridge can apply a significantly varying contact pressure to the photosensitive drum of the drum unit. Such a significantly varying contact pressure between the developing roller and the photosensitive drum may cause the toner to be inappropriately transferred (white spots or color unevenness) onto the paper of the output image.

[0013] In view of the above problems, one or more aspects of the present invention relate to a structure that prevents the contact pressure between the photosensitive drum of the drum unit and the developing roller of the developer cartridge from significantly varying according to the remaining amount of toner in the developer cartridge.

[0014] [Problem-Solving Means]

[0015] (1) The first aspect of the present invention provides a developer cartridge having the following structure. The developer cartridge includes a housing, a developing roller, a first protrusion, and a first pressure receiving surface. The housing extends in a first direction and can accommodate toner. The housing has a first end in the first direction and a second end in the first direction that is farther from the first end. The developing roller is rotatable about a roller axis that extends in a second direction different from the first direction. The developing roller is closer to the first end than to the second end in the first direction. The developing roller has an exposed surface and a covered surface. The exposed surface is located at the first end of the developing roller in a third direction and is exposed outside the housing. The covered surface is located inside the housing at the second end of the developing roller in the third direction. The first protrusion extends in the second direction and is movable together with the housing. The first protrusion is located on a first outer surface of the housing, which is at the first end of the housing in the second direction. When the first protrusion is supported by a support surface of a first side plate of the drum unit, the first protrusion can bear the weight of the developer cartridge. The first protrusion is farther from the developing roller in the first and third directions. The first pressure receiving surface is farther from the developing roller in the third direction than the first protrusion is from the developing roller. The first pressure receiving surface can receive a pressing force in the third direction from a pressing member of the first side plate of the drum unit. The first protrusion is at a first distance from the developing roller in the first direction. The first pressure receiving surface is at the first distance or a second distance from the developing roller in the first direction, and the second distance is less than the first distance.

[0016] With this structure, it is possible to suppress a significant change in the contact pressure between the photosensitive drum of the drum unit and the developing roller of the developer cartridge according to the amount of toner remaining in the developer cartridge.

[0017] (2) Preferably, in the developer cartridge according to the first aspect, the first direction is different from the third direction.

[0018] (3) Preferably, the developer cartridge according to the first aspect or feature (2) can be attached to the drum unit in the first direction.

[0019] (4) Preferably, in the developer cartridge according to the first aspect or any one of features (2)-(3), the first pressure receiving surface is configured to receive a pressing force in the third direction from a pressing member of the first side plate of the drum unit, which is directed from the covered surface to the exposed surface.

[0020] (5) Preferably, when the developer cartridge according to feature (4) is attached to the drum unit, the first protrusion is supported by a support surface of the first side plate of the drum unit, and the first protrusion bears the weight of the developer cartridge.

[0021] With this structure, while the first protrusion bears the weight of the developer cartridge, the first pressure receiving surface can receive a pressing force directed from the covered surface to the exposed surface. Therefore, the developing roller can be brought closer to the photosensitive drum without being affected by the weight of the developer cartridge.

[0022] (6) Further, when the developer cartridge according to feature (5) is attached to the drum unit, preferably, the first pressure receiving surface receives a pressing force in the third direction from the pressing member on the first side plate of the drum unit, which is directed from the covering surface towards the exposed surface.

[0023] With this structure, when the developer cartridge is attached to the drum unit, while the first protrusion is received by the supporting surface of the drum unit, when a pressing force directed from the covering surface towards the exposed surface is received at the first pressure receiving surface, the developing roller can be brought into contact with the photosensitive drum.

[0024] (7) Further, when the developer cartridge according to feature (5) is attached to the drum unit, preferably, the first pressure receiving surface presses against the pressing member on the first side plate of the drum unit to receive a pressing force in the third direction from the covering surface towards the exposed surface.

[0025] With this structure, when the developer cartridge is attached to the drum unit, the first pressure receiving surface contacts the pressing member of the drum unit and is pressed towards the developing roller. Thus, the developing roller is brought into contact with the photosensitive drum of the drum unit.

[0026] (8) Preferably, the developer cartridge according to the first aspect or any one of features (2)-(7) further includes a first ring that is rotatable about the first protrusion, and the first ring is cylindrical or polygonal.

[0027] With this structure, the first protrusion can slide relative to the supporting surface of the drum unit with a relatively small frictional force, so that the developing roller approaches the photosensitive drum of the drum unit.

[0028] (9) Preferably, in the developer cartridge according to the first aspect and any one of features (2)-(8), the first protrusion is a component separate from the housing.

[0029] With this structure, the first protrusion can be assembled to the housing. Therefore, flexibility in the assembly of the developer cartridge can be achieved.

[0030] (10) Preferably, in the developer cartridge according to the first aspect or any one of features (2)-(9), the developing roller is located at the first end of the housing in the third direction, and the first pressure receiving surface is located at the second end of the housing in the third direction, and the second end is away from the first end.

[0031] (11) More preferably, the developer cartridge according to the first aspect or any one of features (2)-(10) further includes a second protrusion that extends in the second direction and is capable of moving together with the housing. The second protrusion is located on the first outer surface. The second protrusion is farther from the developing roller than the first protrusion in the first direction and the third direction. The second protrusion is configured to receive a pressing force from the second end of the housing in the first direction towards the first end of the housing in the first direction.

[0032] (12) Further preferably, the developer cartridge according to feature (11) is configured to pivot about the first protrusion in response to a pressing force received from the second end of the housing in the first direction towards the first end of the housing in the first direction by the second protrusion.

[0033] With this structure, while the first protrusion bears the weight of the developer cartridge, the second protrusion can bear the pressing force from the second end of the housing towards the first end. Thus, the developer cartridge can pivot such that the developing roller can move closer to the photosensitive drum without being affected by the weight of the developer cartridge.

[0034] (13) Preferably, in the developer cartridge according to feature (11), the second protrusion is configured to receive a pressing force from the locking lever of the drum unit.

[0035] (14) In the developer cartridge according to feature (11), it is further preferred that: when the developer cartridge is attached to the drum unit, the second protrusion receives a pressing force from the locking lever of the drum unit from the second end of the housing in the first direction towards the first end of the housing in the first direction; and the first protrusion is supported by the supporting surface of the first side plate of the drum unit, and the first protrusion bears the weight of the developer cartridge.

[0036] (15) Preferably, the developer cartridge according to feature (14) pivots about the first protrusion in response to the second protrusion receiving a pressing force in the first direction from the second end towards the first end.

[0037] With this structure, when the developer cartridge is attached to the drum unit, the second protrusion receives a pressing force from the second end towards the first end, causing the developer cartridge to pivot about the first protrusion to move the developing roller towards the photosensitive drum.

[0038] (16) Preferably, the developer cartridge according to feature (15) further includes a protrusion extending in the second direction, and the protrusion is located at the first end of the developing roller in the second direction. The protrusion contacts the first guiding surface of the drum unit in response to the developer cartridge pivoting about the first protrusion.

[0039] With this structure, when the developer cartridge is attached to the drum unit, the protrusion contacts the first guiding surface to limit further pivoting of the developer cartridge. Thus, the positioning of the developing roller relative to the photosensitive drum can be provided.

[0040] (17) In the developer cartridge according to feature (16), it is preferred that: the developing roller includes a developing roller shaft extending in the second direction; and the protrusion is located at the first end of the developing roller shaft in the second direction.

[0041] With this structure, the first end of the developing roller shaft can be used as the protrusion.

[0042] (18) Further preferably, the developer cartridge according to any one of features (11)-(17) further includes a second ring that is capable of rotating around the second projection, and the second ring is cylindrical or polygonal.

[0043] With this structure, the developer cartridge can pivot smoothly to be attached to the drum unit with less frictional force.

[0044] (19) Further preferably, the developer cartridge according to any one of features (11)-(18) further includes a third projection that extends in the second direction and is capable of moving together with the housing. The third projection is located on the second outer surface of the housing, and the second outer surface is away from the first outer surface in the second direction. The third projection is configured to bear the weight of the developer cartridge when the third projection is supported by the second support surface of the second side plate of the drum unit. The third projection is away from the developing roller in the first direction and the third direction.

[0045] With this structure, the first projection and the third projection that are positioned opposite to each other in the second direction can be supported by the support surface and the second support surface of the drum unit respectively. The developer cartridge can be stably supported.

[0046] (20) Further preferably, the developer cartridge according to feature (19) further includes a second pressure receiving surface that is farther from the developing roller in the third direction than the third projection is from the developing roller. The second pressure receiving surface is away from the first pressure receiving surface in the second direction. The second pressure receiving surface is configured to receive a pressing force in the third direction from the pressing member of the second side plate of the drum unit. The third projection is at a first distance from the developing roller in the first direction, and the second pressure receiving surface is at the first distance or a second distance from the developing roller in the first direction.

[0047] With this structure, when the developer cartridge is attached to the drum unit, the developer cartridge can be pressed at the first pressure receiving surface and the second pressure receiving surface, and the first pressure receiving surface and the second pressure receiving surface are positioned opposite to each other in the second direction. The developer cartridge can move stably toward the photosensitive drum to allow the developer cartridge to be attached to the drum unit.

[0048] (21) Further preferably, in the developer cartridge according to the first aspect or any one of features (2)-(20), the first projection is closer to the developing roller than to the second end of the housing in the first direction.

[0049] (22) Further preferably, in the developer cartridge according to the first aspect or any one of features (2)-(20), the first pressure receiving surface extends beyond at least a part of the first outer surface of the housing in the third direction.

[0050] (23) The second aspect of the present invention provides a developer cartridge having the following structure. The developer cartridge includes a housing, a developing roller, a first projection, and a second projection. The housing extends in a first direction and can accommodate toner. The housing has a first end in the first direction and a second end in the first direction away from the first end. The developing roller is rotatable about a roller axis, and the roller axis extends in a second direction different from the first direction. The developing roller is closer to the first end than to the second end in the first direction. The developing roller has an exposed surface and a covered surface. The exposed surface is located at the first end of the developing roller in a third direction and is exposed outside the housing. The covered surface is located inside the housing at the second end of the developing roller in the third direction. The first projection extends in the second direction and is movable together with the housing. The first projection is located on a second outer surface of the housing, and the second outer surface is located at the first end of the housing in the second direction. The first projection is away from the developing roller in the first and third directions. The second projection extends in the second direction and is movable together with the housing. The second projection is located on a first outer surface. The second projection is farther from the developing roller in the first and third directions than the first projection is from the developing roller.

[0051] With this structure, it is possible to suppress a significant change in the contact pressure between the photosensitive drum of the drum unit and the developing roller of the developer cartridge according to the amount of toner remaining in the developer cartridge.

[0052] (24) Preferably, the developer cartridge according to the second aspect further includes a first ring that can rotate around the first projection.

[0053] With this structure, the first projection can smoothly slide relative to the drum unit with less friction.

[0054] (25) Preferably, the developer cartridge according to feature (24) further includes a second ring that can rotate around the second projection.

[0055] With this structure, the second projection can also smoothly slide relative to the drum unit with less friction.

[0056] (26) Preferably, in the developer cartridge according to the second aspect or any one of features (24)-(25), the first projection is closer to the developing roller than to the second end of the housing in the first direction.

[0057] (27) Preferably, the developer cartridge according to the second aspect or any one of features (24)-(26) further includes a pressure receiving surface that extends in the third direction beyond at least a part of the first outer surface of the housing.

[0058] (28) Preferably, the developer cartridge according to the second aspect or any one of the features (24)-(27) further includes a connector extending from the first outer surface of the housing in a second direction. The connector is rotatable about a connection axis extending in the second direction, and the connection axis is located between the developing roller and the first protrusion in a first direction.

[0059] (29) Optionally, the developer cartridge according to the second aspect or any one of the features (24)-(27) further includes a connector extending from the first outer surface of the housing in a second direction. The connector is rotatable about a connection axis extending in the second direction. The first protrusion is located between the connection axis and the second protrusion in a first direction and a third direction.

[0060] (30) More preferably, in the developer cartridge according to the second aspect or any one of the features (24)-(29), the first direction is different from the third direction.

[0061] (31) Preferably, the developer cartridge according to the second aspect or any one of the features (24)-(30) can be attached to the drum unit in a first direction.

[0062] (32) More preferably, in the developer cartridge according to the second aspect or any one of the features (24)-(31), the first protrusion is configured to bear the weight of the developer cartridge.

[0063] (33) More preferably, in the developer cartridge according to feature (32), the first protrusion is configured to bear the weight of the developer cartridge when the first protrusion is supported by the support surface of the first side plate of the drum unit.

[0064] With this structure, while the first protrusion bears the weight of the developer cartridge, the developer cartridge can pivot.

[0065] (34) More preferably, in the developer cartridge according to the second aspect or any one of the features (24)-(33), the second protrusion is configured to receive a pressing force directed from the second end of the housing in the first direction to the first end of the housing in the first direction.

[0066] (35) More preferably, the developer cartridge according to feature (34) is configured to pivot about the first protrusion in response to the second protrusion receiving a pressing force directed from the second end of the housing in the first direction to the first end of the housing in the first direction.

[0067] With this structure, while the first protrusion bears the weight of the developer cartridge, the developer cartridge can pivot about the first protrusion toward the photosensitive drum of the drum unit by receiving a pressing force through the second protrusion, and the pressing force is directed from the second end to the first end of the housing.

[0068] (36) Further optionally, in the developer cartridge according to feature (34) or feature (35), the second protrusion is configured to receive a pressing force from the locking lever of the drum unit that points from the second end of the housing in the first direction to the first end of the housing in the first direction.

[0069]

Advantages of the Invention

[0070] By using the structures according to the first and second aspects of the present disclosure, the contact pressure between the photosensitive drum of the drum unit and the developing roller of the developer cartridge can be restricted from varying significantly according to the amount of toner remaining in the developer cartridge. Description of the Drawings

[0071] Figure 1 is a conceptual diagram of an image forming apparatus;

[0072] Figure 2 is a perspective view of the drum unit and the developer cartridge;

[0073] Figure 3 is a perspective view of the developer cartridge;

[0074] Figure 4 is from a direction Figure 3 different from the perspective view of the developer cartridge;

[0075] Figure 5 is a side view of the developer cartridge at one end in the second direction;

[0076] Figure 6 is a side view of the developer cartridge at the other end in the second direction;

[0077] Figure 7 is a perspective view of the drum unit;

[0078] Figure 8 is a side view of the drum unit illustrating the internal structure of the drum unit during the process of attaching a developer cartridge to the drum unit;

[0079] Figure 9 is a side view of the drum unit illustrating the internal structure of the drum unit with the developer cartridge attached to the drum unit;

[0080] Figure 10 is a side view of the developer cartridge during the process of attaching to the drum unit;

[0081] Figure 11 is a side view of the developer cartridge to be attached to the drum unit; and

[0082] Figure 12 is a schematic diagram depicting the interacting forces during the process of attaching the developer cartridge to the drum unit. Detailed Description of the Invention

[0083] Embodiments of the present disclosure will now be described with reference to the accompanying drawings.

[0084] The first direction herein refers to the longitudinal direction of each end face of the developer cartridge. The second direction herein refers to the direction along the rotation axis of the photosensitive drum. The third direction herein refers to the direction in which a plurality of photosensitive drums are aligned with each other. The first direction, the second direction, and the third direction intersect with each other (preferably, at right angles).

[0085] 1. Structure of the image forming apparatus

[0086] Figure 1 is a conceptual diagram of an image forming apparatus 100 according to an embodiment. The image forming apparatus 100 is an electrophotographic printer. The image forming apparatus 100 may be a laser printer or a light emitting diode (LED) printer. As Figure 1 shown, the image forming apparatus 100 includes a drum unit 3 and a plurality of developer cartridges 1. The drum unit 3 includes a frame configured to hold the developer cartridges 1.

[0087] Figure 2 is a perspective view of the drum unit 3 and the developer cartridge 1. The developer cartridge 1 can be individually attached to the drum unit 3. The drum unit 3 holding the developer cartridge 1 is configured to be attached to the main body case 101 of the image forming apparatus 100 (see Figure 1 ). Each developer cartridge 1 contains toner (developer) of a different color (e.g., cyan, magenta, yellow, or black). The image forming apparatus 100 is configured to form (output) an image on the recording surface of a printing sheet using the toner supplied from the developer cartridge 1. The drum unit 3 in the present embodiment is configured to hold four developer cartridges 1. In some embodiments, the drum unit 3 may hold one to three, or five or more developer cartridges 1.

[0088] 2. Structure of the developer cartridge

[0089] Figure 3 and 4 are perspective views of the developer cartridge 1. Figure 5 and 6 show an end face of the developer cartridge 1 observed in the second direction. As Figures 3 to 6 shown, each of the developer cartridges 1 according to the present embodiment includes a housing 11, a developing roller 12, an agitator (not shown), and a coupler 24.

[0090] The housing 11 is a casing configured to contain toner. The housing 11 has a chamber (not shown) configured to accommodate toner. The housing 11 extends in a second direction. The housing 11 has a first outer surface 111 and a second outer surface 112 that is away from the first outer surface 111 in the second direction. The first outer surface 111 is one end surface (the first end surface) of the housing 11 in the second direction. The longitudinal direction of the first outer surface 111 corresponds to the first direction. The second outer surface 112 is the other end surface (the second end surface) of the housing 11 in the second direction. The longitudinal direction of the second outer surface 112 corresponds to the first direction. The housing 11 has a first end 113 in the first direction and a second end 114 that is away from the first end 113 in the first direction. The housing 11 has a first end 11F in the third direction and a second end 11R that is away from the first end 11F in the third direction.

[0091] The developing roller 12 can rotate about a roller axis extending in the second direction. The developing roller 12 is located between the first outer surface 111 and the second outer surface 112 of the housing 11 in the second direction. The developing roller 12 is closer to the first end 113 than to the second end 114 in the first direction. The developing roller 12 is located at one end (the first end 11F) of the housing 11 in the third direction. In other words, the developing roller 12 is located at an outer surface (the third outer surface) of the housing 11 in the third direction.

[0092] More specifically, the developing roller 12 includes a cylindrical developing roller body and a cylindrical developing roller shaft 12c. The developing roller shaft 12c extends through the center of the developing roller body in the second direction. The developing roller body rotates together with the developing roller shaft 12c. The developing roller shaft 12c has two ends in the second direction, and the two ends are rotatably supported by the corresponding end surfaces of the housing 11 in the second direction. More specifically, the developing roller shaft 12c has a first end 12cL and a second end 12cR in the second direction. The first end 12cL is rotatably supported by the first outer surface 111 of the housing 11, and the second end 12cR is rotatably supported by the second outer surface 112 of the housing 11.

[0093] The developing roller 12 (the developing roller body) has an exposed surface 12a and a covered surface 12b. The exposed surface 12a is located at one end (the first end 12F) of the developing roller 12 in the third direction and is exposed to the outside of the housing 11. The covered surface 12b is located at the other end (the second end 12R) of the developing roller 12 in the third direction and is located inside the housing 11. When the developer cartridge 1 is attached to the drum unit 3, the outer peripheral surface of the developing roller 12 contacts the outer peripheral surface of the corresponding photosensitive drum 31.

[0094] A stirrer (not shown) can rotate about a stirrer axis extending in a second direction. The stirrer includes a plurality of stirring blades. The stirrer is located between a first outer surface 111 of the housing 11 and a second outer surface 112 of the housing 11 in the second direction. In a first direction, the stirrer is closer to the second end 114 than to the developing roller 12. The stirrer rotates to stir the toner accommodated in the chamber of the housing 11.

[0095] Figure 3 and 5 The coupler 24 shown in is configured to receive a driving force from the main body housing 101 of the image forming apparatus 100. The coupler 24 can rotate about a coupler axis extending in a second direction. The coupler 24 is closer to the second end 114 than to the developing roller 12 in the first direction. The coupler 24 has a recess 115 that is recessed inward in the second direction. When the developer cartridge 1 attached to the drum unit 3 is attached to the main body housing 101 of the image forming apparatus 100, the drive shaft of the main body housing 101 of the image forming apparatus 100 is received in the recess 115. The coupler 24 is thus connected to the drive shaft so as not to rotate relative to the drive shaft. Rotation of the drive shaft causes the coupler 24 to rotate. Rotation of the coupler 24 then causes the developing roller 12 and the stirrer to rotate.

[0096] 3. Structure of the drum unit

[0097] Now, the structure of the drum unit 3 will be mainly described with reference to Figure 7 The structure of the drum unit 3 will be described. Figure 7 is a perspective view of the drum unit 3.

[0098] As Figures 7 to 9 shown, the drum unit 3 includes a plurality of photosensitive drums 31, a first side plate 33, a second side plate 34, and a pull-out plate 35. In this embodiment, the drum unit 3 includes four photosensitive drums 31.

[0099] The photosensitive drums 31 are configured to transfer the toner fed from the developer cartridge 1 to the printing sheet. The photosensitive drums 31 are arranged in a row at a certain distance in a third direction. Each photosensitive drum 31 is cylindrical. Each photosensitive drum 31 has an outer peripheral surface. Each photosensitive drum 31 extends in a second direction. The outer peripheral surface of the photosensitive drum 31 is coated with a photosensitive material. Each photosensitive drum 31 can rotate about a drum axis extending in a second direction.

[0100] The first side plate 33, the second side plate 34, and the pull-out plate 35 together define a frame. The frame is configured to hold the photosensitive drums 31. The frame has an opening at one end of the frame in a first direction (the direction opposite to gravity in this embodiment).

[0101] The first side plate 33 supports the first end of the photosensitive drum 31 in the second direction. The first side plate 33 extends perpendicular to the second direction. The first side plate 33 extends in the third direction. The first side plate 33 is a plate. The first side plate 33 includes a plurality (four in this embodiment) of developer cartridge holders 30. The developer cartridge holders 30 are located on the inner surface of the first side plate 33 in the second direction. The developer cartridge holders 30 of the first side plate 33 are arranged in rows at intervals in the third direction. The developer cartridge holders 30 of the first side plate 33 are configured to receive the first ends 1L (the ends at the first outer surface 111) of the developer cartridges 1 in the first direction respectively.

[0102] The second side plate 34 supports the second end of the photosensitive drum 31 in the second direction. The second side plate 34 extends perpendicular to the second direction. The second side plate 34 extends in the third direction. The second side plate 34 is a plate. The second side plate 34 includes a plurality (four in this embodiment) of developer cartridge holders (not shown). The developer cartridge holders are located on the inner surface of the second side plate 34 in the second direction. The number of the developer cartridge holders of the second side plate 34 is equal to the number of the developer cartridge holders 30 of the first side plate 33. The developer cartridge holders of the second side plate 34 are configured to receive the second ends 1R (the ends at the second outer surface 112) of the developer cartridges 1 in the second direction respectively.

[0103] The pull-out plate 35 connects the second end 33F of the first side plate 33 in the third direction and the second end 34F of the second side plate 34 in the third direction. The pull-out plate 35 extends perpendicular to the third direction. The pull-out plate 35 extends in the second direction. The pull-out plate 35 is a plate. The pull-out plate 35 has a handle 36. The handle 36 is located on the outer surface of the pull-out plate 35 in the third direction. The handle 36 is grasped by the user to pull out or push in the drum unit 3 into the main body housing 101.

[0104] When the developer cartridge 1 is attached to the drum unit 3, the first end (the first outer surface 111) of the outer shell 11 in the second direction is held by the developer cartridge holders 30 of the first side plate 33 and the second end (the second outer surface 112) of the outer shell 11 in the second direction is held by the developer cartridge holders in the second side plate 34. When the developer cartridge 1 is attached to the drum unit 3, the outer peripheral surface (the exposed surface 12a) of the developing roller 12 contacts the outer peripheral surface of the corresponding photosensitive drum 31.

[0105] The image forming apparatus 100 having the above structure is configured to form an image on a print sheet. As the corresponding connectors 24 and the photosensitive drum 31 rotate, toner is fed from the chamber of the housing 11 to the outer peripheral surface of the photosensitive drum 31 through the developing roller 12. According to the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 31, the toner held on the outer peripheral surface of the developing roller 12 moves from the developing roller 12 to the corresponding photosensitive drum 31. The electrostatic latent image is thus developed into a visible toner image on the outer peripheral surface of the photosensitive drum 31. The toner image on the photosensitive drum 31 is then transferred onto the print sheet.

[0106] 4. Detailed structure of attachment and removal

[0107] Now, reference will be made to Figures 3 to 12 describe the structure according to the present embodiment for attaching the developer cartridge 1 to the drum unit 3 and removing it therefrom. Figure 8 is a side view of the drum unit 3 showing the internal structure of the drum unit 3 during the process of attaching one developer cartridge 1. Figure 9 is a side view of the drum unit 3 illustrating the internal structure of the drum unit 3 to which the developer cartridge 1 is attached. Figure 11 is a side view of the developer cartridge 1 during the process of attaching it to the developer cartridge holder 30 of the drum unit 3. Figure 11 is a side view of the developer cartridge 1 attached to the developer cartridge holder 30 of the drum unit 3. Figure 12 is a schematic diagram describing the forces interacting during the process of attaching the developer cartridge 1 to the developer cartridge holder 30 of the drum unit 3.

[0108] The developer cartridge 1 according to the present embodiment includes a first projection 13, a first ring 14, a first pressure receiving surface (pressure receiving surface) 15, a second projection 16, a second ring 17, a first protrusion 18, a third projection 19, a second pressure receiving surface 21, a fourth projection 22, and a second protrusion 23.

[0109] The first projection 13 extends in the second direction. The first projection 13 in the present embodiment is a component separated from the housing 11 and is fixed to the housing 11. In some embodiments, the first projection 13 may be integral with the housing 11. The first projection 13 may move together with the housing 11. The first projection 13 is located on the first outer surface 111. More specifically, the first projection 13 projects outward from the first outer surface 111 in the second direction. As will be described in detail later, the first projection 13 can bear the weight of the developer cartridge 1. The first projection 13 is away from the developing roller 12 in the first and third directions. As will be described in detail later, when the developer cartridge 1 is attached to the drum unit 3, the first projection 13 is supported by the support surface 41 (described later) of the drum unit 3.

[0110] The first ring 14 is cylindrical. The first ring 14 is capable of rotating around the first projection 13. The first ring 14 has a hollow. The first ring 14 receives the first projection 13 in the hollow. In some embodiments, the first ring 14 may not be cylindrical. For example, the first ring 14 may be polygonal. The developer cartridge 1 may not include the first ring 14. In this case, the outer peripheral surface of the first projection 13 may be used as the first ring.

[0111] The first pressure receiving surface 15 is an arcuate surface that is curved along an arc centered on a straight line extending in the second direction. The first pressure receiving surface 15 is located inside the first outer surface 111 in the second direction. In the third direction, the first pressure receiving surface 15 is farther from the developing roller 12 than the first projection 13 is from the developing roller 12. The first pressure receiving surface 15 is located at the second end 11R (opposite to the developing roller 12) of the housing 11 in the third direction. In other words, the first pressure receiving surface 15 is located on the outer surface of the second end 11R of the housing 11 in the third direction. The first pressure receiving surface 15 extends in the third direction beyond at least a portion of the first outer surface 111 of the housing 11.

[0112] The first projection 13 is located at a first distance D1 from the developing roller 12 in the first direction. The first pressure receiving surface 15 is located at a second distance D2 (D2 ≤ D1) that is equal to or less than the first distance D1 from the developing roller 12 in the first direction. In the present embodiment, as Figure 5 and 6 shown, the distance between the first pressure receiving surface 15 and the developing roller 12 in the first direction is substantially equal to the first distance D1.

[0113] In the present embodiment, the first distance D1 may be defined as the maximum distance in the first direction between the outer peripheral surface of the first projection 13 and the outer peripheral surface of the developing roller 12, and the second distance D2 may be defined as the maximum distance in the first direction between the outer surface of the first pressure receiving surface 15 and the outer peripheral surface of the developing roller 12. In some embodiments, these distances may be defined differently. For example, the first distance D1 may be defined as the distance in the first direction between the center of the first projection 13 and the rotation center (axis) of the developing roller 12, and the second distance D2 may be defined as the distance in the first direction between the center of the arc defined by the outer surface of the first pressure receiving surface 15 and the rotation center (axis) of the developing roller 12. In other embodiments, the first distance D1 may be the distance in the first direction between the outer surface of the first projection 13 and the outer peripheral surface of the developing roller shaft 12c, and the second distance D2 may be the distance in the first direction between the outer surface of the first pressure receiving surface 15 and the outer peripheral surface of the developing roller shaft 12c.

[0114] The second protrusion 16 extends in the second direction. The second protrusion 16 in this embodiment is a component separated from the housing 11 and is fixed to the housing 11. In some embodiments, the second protrusion 16 may be integral with the housing 11. The second protrusion 16 can move together with the housing 11. The second protrusion 16 is located on the first outer surface 111. More specifically, the second protrusion 16 protrudes outward from the first outer surface 111 in the second direction. In the first and third directions, the distance of the second protrusion 16 from the developing roller 12 is farther than the distance of the first protrusion 13 from the developing roller 12. In other words, the second protrusion 16 is opposite to the developing roller 12 relative to the first protrusion 13 in the first direction. The second protrusion 16 is opposite to the developing roller 12 relative to the first protrusion 13 in the third direction. As will be described in detail later, when the developer cartridge 1 is attached to the drum unit 3, the second protrusion 16 is configured to receive a pressing force pointing from the second end 114 to the first end 113 in the first direction.

[0115] The second ring 17 is cylindrical. The second ring 17 is capable of rotating around the second protrusion 16. The second ring 17 has a hollow. The second ring 17 receives the second protrusion 16 in the hollow. In some embodiments, the second ring 17 may not be cylindrical. For example, the second ring 17 may have a polygonal shape. The developer cartridge 1 may not include the second ring 17. In this case, the outer peripheral surface of the second protrusion 16 can be used as the second ring.

[0116] The first protrusion 18 extends in the second direction. The first protrusion 18 is located at the first end of the developing roller 12 in the second direction. More specifically, the first protrusion 18 is located at the first end 12cL of the developing roller shaft 12c in the second direction. The first protrusion 18 is a component separated from the developing roller 12 and is attached to the developing roller 12. More specifically, the first protrusion 18 is a component separated from the developing roller shaft 12c and is attached to the developing roller shaft 12c. In some embodiments, the first protrusion 18 may be integral with the developing roller 12. More specifically, the first protrusion 18 may be integral with the developing roller shaft 12c. As will be described in detail later, when the developer cartridge 1 is attached to the drum unit 3, the first protrusion 18 contacts the guide 49 of the drum unit 3. Thus, the first protrusion 18 is used to position the developer cartridge 1 relative to the drum unit 3.

[0117] Figure 4 and 6The third protrusion 19 shown in [the figure] extends in the second direction. The third protrusion 19 in this embodiment is a component separated from the housing 11 and is fixed to the housing 11. In some embodiments, the third protrusion 19 may be integral with the housing 11. The third protrusion 19 can move together with the housing 11. The third protrusion 19 is located at the second outer surface 112. More specifically, the third protrusion 19 protrudes outward from the second outer surface 112 in the second direction. The third protrusion 19 is located on the axis of the first protrusion 13 extending in the second direction. As will be described in detail later, the third protrusion 19 and the first protrusion 13 are configured together to bear the weight of the developer cartridge 1. The developer cartridge 1 further includes a third ring (not shown with a reference numeral) that can rotate around the third protrusion 19, which is similar to the first ring 14.

[0118] The second pressure receiving surface 21 is an arcuate surface that curves along an arc centered on a straight line extending in the first direction. The second pressure receiving surface 21 is away from the first pressure receiving surface 15 in the second direction. The second pressure receiving surface 21 is located inside the second outer surface 112 in the second direction. When viewed in the second direction, the second pressure receiving surface 21 overlaps with the first pressure receiving surface 15. In other words, the second pressure receiving surface 21 is farther from the developing roller 12 in the third direction than the third protrusion 19 is from the developing roller 12.

[0119] The third protrusion 19 is located at a first distance D1 from the developing roller 12 in the first direction. The second pressure receiving surface 21 is located at a second distance D2 (D2 ≤ D1) that is the first distance D1 or less than the first distance D1 from the developing roller 12 in the first direction.

[0120] The fourth protrusion 22 extends in the second direction. The fourth protrusion 22 in this embodiment is a component separated from the housing 11 and is fixed to the housing 11. In some embodiments, the fourth protrusion 22 may be integral with the housing 11. The fourth protrusion 22 can move together with the housing 11. The fourth protrusion 22 is located at the second outer surface 112. More specifically, the fourth protrusion 22 protrudes outward from the second outer surface 112 in the second direction. The fourth protrusion 22 is located on the axis of the second protrusion 16 extending in the second direction. The developer cartridge 1 has a fourth ring (not shown with a reference numeral) that can rotate around the fourth protrusion 22, which is similar to the second ring 17.

[0121] The second protrusion 23 extends in the second direction. The second protrusion 23 is located at the second end of the developing roller 12 in the second direction. More specifically, the second protrusion 23 is located at the second end 12cR of the developing roller shaft 12c in the second direction. The second protrusion 23 is a component separated from the developing roller 12 and is attached to the developing roller 12. More specifically, the second protrusion 23 is a component separated from the developing roller shaft 12c and is attached to the developing roller shaft 12c. In some embodiments, the second protrusion 23 may be integral with the developing roller 12. More specifically, the second protrusion 23 may be integral with the developing roller shaft 12c. The second protrusion 23 is located on the axis of the first protrusion 18 that extends in the second direction. As will be described in detail later, the second protrusion 23 and the first protrusion 18 are used together to position the developer cartridge 1 relative to the drum unit 3.

[0122] The image forming apparatus 100 according to the present embodiment includes a developer cartridge holder 30 on the first side plate 33 and a developer cartridge holder on the second side plate 34. More specifically, as Figure 8 and 9 shown, each of the developer cartridge holders 30 on the first side plate 33 and the developer cartridge holders on the second side plate 34 in the present embodiment includes a support member 46, a pressing member 47, a locking lever 48, and a guide member 49. The support member 46, the pressing member 47, the locking lever 48, and the guide member 49 in each developer cartridge holder 30 on the first side plate 33 are paired with these components in the corresponding developer cartridge holder on the second side plate 34. Since each developer cartridge holder on the second side plate 34 has a structure symmetric to each of the developer cartridge holders 30 on the first side plate 33, the developer cartridge holder 30 on the first side plate 33 will be mainly described below without repeatedly describing the developer cartridge holder on the second side plate 34.

[0123] As Figure 10 shown, the support member 46 has a support surface 41. The support member 46 protrudes inward from the inner surface of the first side plate 33 in the second direction. The support surface 41 faces the direction opposite to gravity. The support surface 41 is a flat surface perpendicular to the first direction. When the developer cartridge 1 is attached to the developer cartridge holder 30 of the drum unit 3, the support surface 41 supports the first protrusion 13 through the first ring 14.

[0124] The pressing member 47 has a first pressing surface 42. The pressing member 47 is located on the inner surface of the first side plate 33. The first pressing surface 42 is a flat surface that is generally perpendicular to the third direction. The first pressing surface 42 can slide in the third direction relative to the first side plate 33. The pressing member 47 includes a spring (not shown) as an elastic member. When the first pressing surface 42 moves in the third direction toward the second end 3R of the drum unit 3 (in the direction away from the pull-out plate 35), the spring of the pressing member 47 presses the first pressing surface 42 backward in the third direction toward the first end 3F of the drum unit 3 (toward the pull-out plate 35). When the developer cartridge 1 is attached to the developer cartridge holder 30 of the drum unit 3, the first pressing surface 42 contacts the first pressure receiving surface 15 of the outer shell 11 of the corresponding developer cartridge 1. The first pressure receiving surface 15 receives the pressing force from the first pressing surface 42 that points from the second end 3R of the drum unit 3 in the third direction to the first end 3F of the drum unit 3 in the third direction.

[0125] The locking lever 48 is located at the first end 33U (the end in the direction opposite to gravity) of the first side plate 33 in the first direction. The locking lever 48 has a second pressing surface 43 and a guiding surface 51. The guiding surface 51 is an arc-shaped surface that protrudes inward in the second direction (see Figure 7 ). The second pressing surface 43 is a flat surface that is continuous with the guiding surface 51. The locking lever 48 can pivot between a locked position and a released position about a pivot axis extending in the third direction. When the locking lever 48 is in the locked position, the guiding surface 51 is at least partially located between the first side plate 33 and the second side plate 34, and the second pressing surface 43 is generally perpendicular to the first direction and faces the second end 3D of the drum unit 3 in the first direction. When the locking lever 48 is in the released position, the guiding surface 51 is farther from the second side plate 34 in the second direction than when the locking lever 48 is in the locked position. The locking lever 48 includes a spring (not shown) as an elastic member. The spring in the locking lever 48 presses the second pressing surface 43 toward the locked position. When the corresponding developer cartridge 1 is attached to the developer cartridge holder 30 of the drum unit 3, the second pressing surface 43 contacts the second protrusion 16 through the second ring 17. The second protrusion 16 receives the pressing force from the second pressing surface 43 that points from the first end 3U of the drum unit 3 in the first direction to the second end 3D (downward) of the drum unit 3.

[0126] The guide member 49 has a first guide surface 44 and a second guide surface 45. The guide member 49 is located on the inner surface of the first side plate 33. The guide member 49 is in an arc shape in a side view. The first guide surface 44 is a flat surface substantially perpendicular to the first direction. When the developer cartridge 1 is pivoted about the first projection 13 to move the developer roller 12 toward the photosensitive drum 31 during the process of attaching the developer cartridge 1 to the developer cartridge holder 30 of the drum unit 3, the first guide surface 44 contacts the first protrusion 18. Thus, the first guide surface 44 is used to position the developer cartridge 1 relative to the drum unit 3.

[0127] The second guide surface 45 has a flat surface and an inclined surface continuous with the flat surface. The flat surface is substantially perpendicular to the first direction. One end of the inclined surface in the third direction (the end closer to the first guide surface 44) is connected to the flat surface. The inclined surface is an inclined surface extending from the flat surface toward the second end 33D of the first side plate 33 in the first direction and toward the second end 33F of the first side plate 33 in the third direction. When the developer cartridge 1 is pivoted about the first projection 13 to move the developer roller 12 toward the photosensitive drum 31 during the process of attaching the developer cartridge 1 to the developer cartridge holder 30 of the drum unit 3, the second guide surface 45 is spaced apart from the first protrusion 18 in the first direction.

[0128] 6. Forces Acting on Each Other When Attaching the Developer Cartridge

[0129] Now, reference will be made to Figures 8 to 12 describe the forces acting on each other during the process of attaching the developer cartridge 1 to the drum unit 3.

[0130] To attach the developer cartridge 1 to the drum unit 3, the user first holds the developer cartridge 1 such that the first end 113 of the housing 11 in the first direction faces the second end 3D of the drum unit 3 in the first direction. Then the user inserts the developer cartridge 1 into the corresponding developer cartridge holders (the developer cartridge holder 30 of the first side plate 33 and the developer cartridge holder of the second side plate 34) in the first direction toward the second end 3D of the drum unit 3 (see Figure 8 ). As a result, the first projection 13 is supported by the support surface 41 of the drum unit 3 through the first ring 14 in the first direction. Similarly, the third projection 19 is supported by the support surface 41 of the drum unit 3 through the third ring in the first direction. The support surface 41 bears the weight of the developer cartridge 1.

[0131] Meanwhile, as the user inserts the developer cartridge 1 into the drum unit 3 toward the second end 3D of the drum unit 3 in the first direction, the arcuate guide surface 51 is pushed by the second protrusion 16 (second ring 17) to smoothly pivot outward in the second direction against the pressing force of the spring of the locking lever 48. The locking lever 48 of the developer cartridge holder 30 thus moves to the release position. Similarly, in the developer cartridge holder of the second side plate 34, the guide surface 51 is pushed by the fourth protrusion 22 (fourth ring) to smoothly pivot outward against the pressing force of the spring of the locking lever 48, moving the locking lever 48 to the release position. The developer cartridge 1 is thus allowed to move toward the second end 3D of the drum unit 3 in the first direction. The second protrusion 16 is closer to the second end 3D of the drum unit 3 in the first direction than the locking lever 48 is to the second end 3D of the drum unit 3 in the first direction. The fourth protrusion 22 is closer to the second end 3D of the drum unit 3 in the first direction than the corresponding locking lever 48 is to the second end 3D of the drum unit 3 in the first direction. Subsequently, the second pressing surface 43 under the pressing force of the spring of the corresponding locking lever 48 pivots inward in the second direction and places the locking lever 48 in the locking position.

[0132] As Figure 10 shown, the second protrusion 16 (second ring 17) contacts the second pressing surface 43 in the locked position to receive from the second pressing surface 43 a pressing force in the first direction pointing from the second end 114 of the housing 11 toward the first end 113 of the housing 11. Similarly, the fourth protrusion 22 (fourth ring) contacts the second pressing surface 43 in the locked position to receive from the second pressing surface 43 a pressing force in the first direction pointing from the second end 114 of the housing 11 toward the first end 113 of the housing 11. At this position, the first protrusion 13 and the third protrusion 19 are each supported from below (from the second end 3D side of the drum unit 3) by the corresponding support surface 41 in the first direction. As a result, a torque about the first protrusion 13 (about the third protrusion 19) is generated in the developer cartridge 1. This causes the developer cartridge 1 to pivot slightly about the first protrusion 13 (about the third protrusion 19) in the drum unit 3 to move the developing roller 12 toward the photosensitive drum 31. As the developing roller 12 moves toward the photosensitive drum 31, the first projection 18 contacts the first guide surface 44 to stop the pivoting movement of the developer cartridge 1 about the first protrusion 13. At the same time, the second projection 23 contacts the first guide surface 44 to stop the pivoting movement of the developer cartridge 1 about the third protrusion 19. This contact determines the contact angle between the developing roller 12 and the photosensitive drum 31 and properly positions the developing roller 12 relative to the photosensitive drum 31. In other words, the developer cartridge 1 is positioned in the drum unit 3.

[0133] Further, as the user inserts the developer cartridge 1 into the drum unit 3 toward the second end 3D of the drum unit 3 in the first direction, each first pressing surface 42 is pushed by the first pressure receiving surface 15 or the second pressure receiving surface 21, and moves toward the second end 3R of the drum unit 3 in the third direction against the pressing force of the spring in the pressing member 47. Thus, while or after the developer cartridge 1 pivots slightly around the first projection 13, the first pressure receiving surface 15 receives from the corresponding first pressing surface 42 a pressing force in the third direction from the covering surface 12b toward the exposed surface 12a. Similarly, thus, while or after the developer cartridge 1 pivots slightly around the third projection 19, the first pressure receiving surface 15 receives from the corresponding first pressing surface 42 a pressing force in the third direction from the covering surface 12b toward the exposed surface 12a. At this position, the support surface 41 receives the weight of the developer cartridge 1 applied through the first projection 13 and the third projection 19. Thus, each of the first projection 13 (first ring 14) and the third projection 19 (third ring) slides toward the first end 3F of the drum unit 3 in the third direction while being supported by the corresponding support surface 41. This moves the developing roller 12 further toward the photosensitive drum 31 and allows the outer peripheral surface of the developing roller 12 (developing roller body) to contact the outer peripheral surface of the photosensitive drum 31 with an appropriate contact pressure. At this position, since the support surface 41 bears the weight of the developer cartridge 1, the weight of the developer cartridge 1 is less likely to affect the contact pressure between the developing roller 12 and the photosensitive drum 31. This structure can suppress a significant change in the contact pressure between the developing roller 12 and the photosensitive drum 31 according to the amount of toner remaining in the developer cartridge 1.

[0134] Just before the outer peripheral surface of the developing roller 12 (developing roller body) contacts the outer peripheral surface of the photosensitive drum 31, the first protrusion 18 is held between the first guide surface 44 and the second guide surface 45 in the first direction (see Figure 10 ). The developing roller 12 can be properly positioned relative to the photosensitive drum 31. The inclined surface of the second guide surface 45 smoothly guides the developing roller 12 toward the position between the flat surfaces of the first guide surface 44 and the second guide surface 45.

[0135] In the above-described manner, when the developer cartridge 1 is attached to the drum unit 3, the developer cartridge 1 is properly positioned relative to the drum unit 3. At this time, since the locking lever 48 is in the locked position, even if the image forming apparatus 100 is subjected to vibration or impact, the developer cartridge 1 is not easily detached from the drum unit 3. The structure according to the present embodiment allows the developer cartridge 1 to be reliably attached to or removed from the drum unit 3.

[0136]

List of Reference Signs

[0137] 1: Developer Cartridge

[0138] 11: Housing

[0139] 12: Developing roller

[0140] 12a: Exposed surface

[0141] 12b: Covered surface

[0142] 12c: Developing roller shaft

[0143] 13: First protrusion

[0144] 14: First ring

[0145] 15: First pressure receiving surface

[0146] 16: Second protrusion

[0147] 17: Second ring

[0148] 18: First projection

[0149] 19: Third protrusion

[0150] 22: Fourth protrusion

[0151] 23: Second projection

[0152] 31: Photoconductor drum

[0153] 41: Support surface

[0154] 42: First pressing surface

[0155] 43: Second pressing surface

[0156] 44: First guiding surface

[0157] 45: Second guiding surface

[0158] 48: Locking lever

[0159] 100: Image forming apparatus

[0160] 111: First outer surface

[0161] 112: Second outer surface

[0162] 113: First end

[0163] 114: Second end

[0164] D1: First distance

[0165] D2: Second distance

Claims

1. A developer cartridge, characterized in that, Comprising: A housing that extends in a first direction and is configured to contain toner, the housing having a first end in the first direction and a second end in the first direction that is remote from the first end; A developing roller that is rotatable about a roller axis extending in a second direction different from the first direction, the developing roller being closer to the first end than to the second end in the first direction, the developing roller having an exposed surface and a covered surface, the exposed surface being at a first end of the developing roller in a third direction and being exposed outside the housing, the covered surface being at a second end of the developing roller in the third direction and being located inside the housing; A first protrusion that extends in the second direction and is movable with the housing, the first protrusion being located on a first outer surface of the housing in the second direction, the first protrusion being configured to bear the weight of the developer cartridge when the first protrusion is supported by a support surface of a first side plate of the drum unit, the first protrusion being remote from the developing roller in the first direction and the third direction; And A first pressure receiving surface that is farther from the developing roller in the third direction than the first protrusion is from the developing roller, the first pressure receiving surface being configured to receive a pressing force in the third direction from a pressing member of the first side plate of the drum unit that is directed from the covered surface toward the exposed surface; Wherein, in the first direction, a distance between the first protrusion and the developing roller is a first distance; and Wherein, in the first direction, a distance between the first pressure receiving surface and the developing roller is the first distance or a second distance less than the first distance.

2. The developer cartridge according to claim 1, wherein, The first direction is different from the third direction.

3. The developer cartridge according to claim 1, wherein , The developer cartridge is attachable to the drum unit in the first direction.

4. The developer cartridge according to claim 1, wherein, When the developer cartridge is attached to the drum unit, the first pressure receiving surface receives the pressing force in the third direction from the pressing member of the first side plate of the drum unit that is directed from the covered surface toward the exposed surface.

5. The developer cartridge according to claim 1, wherein, When the developer cartridge is attached to the drum unit, the first pressure receiving surface is pressed against the pressing member of the first side plate of the drum unit to receive the pressing force in the third direction from the covered surface toward the exposed surface.

6. The developer cartridge according to any one of claims 1 to 5, characterized in that, Further comprising a first ring that is rotatable about the first protrusion, the first ring being cylindrical or polygonal.

7. The developer cartridge according to any one of claims 1 to 5, characterized in that, The first protrusion is a component separated from the housing.

8. The developer cartridge according to any one of claims 1 to 5, characterized in that, The developing roller is located at a first end of the housing in the third direction, and the first pressure receiving surface is located at a second end of the housing in the third direction, the second end being remote from the first end of the housing.

9. The developer cartridge according to any one of claims 1 to 5, characterized in that, Further comprising: A second protrusion that extends in the second direction and is movable with the housing, the second protrusion being located on the first outer surface, the second protrusion being farther from the developing roller than the first protrusion in the first direction and the third direction, the second protrusion being configured to receive a pressing force directed from the second end of the housing in the first direction to the first end of the housing in the first direction.

10. The developer cartridge according to claim 9, wherein, The second protrusion is configured to receive the pressing force from the locking lever of the drum unit.

11. The developer cassette according to claim 9, wherein, When the developer cartridge is attached to the drum unit, the second protrusion receives the pressing force directed from the second end of the housing in the first direction to the first end of the housing in the first direction from the locking lever of the drum unit, the first protrusion is supported by the support surface of the first side plate of the drum unit, and the first protrusion bears the weight of the developer cartridge.

12. The developer cartridge according to claim 11, wherein, The developer cartridge pivots about the first protrusion in response to the second protrusion receiving the pressing force directed from the second end to the first end in the first direction.

13. The developer cassette according to claim 12, characterized in that, Further includes a protrusion that extends in the second direction, the protrusion being located at the first end of the developing roller in the second direction; Wherein, the protrusion contacts the first guiding surface of the drum unit in response to the developer cartridge pivoting about the first protrusion.

14. The developer cartridge according to claim 13, wherein, The developing roller includes a developing roller shaft that extends in the second direction, and the protrusion is located at the first end of the developing roller shaft in the second direction.

15. A developer cartridge, characterized in that, Comprises: A housing that extends in a first direction and is configured to contain toner, the housing having a first end in the first direction and a second end that is remote from the first end in the first direction; A developing roller that is rotatable about a roller axis extending in a second direction different from the first direction, the developing roller being closer to the first end than to the second end in the first direction, the developing roller having an exposed surface and a covered surface, the exposed surface being located at the first end of the developing roller in a third direction and being exposed outside the housing, the covered surface being located at the second end of the developing roller in the third direction and being located inside the housing; A first protrusion that extends in the second direction and is movable with the housing, the first protrusion being located on the first outer surface of the housing in the second direction, the first protrusion being remote from the developing roller in the first direction and the third direction; A second protrusion that extends in the second direction and is movable with the housing, the second protrusion being located on the first outer surface, the second protrusion being farther from the developing roller than the first protrusion in the first direction and the third direction; And A first pressure receiving surface that is farther from the developing roller than the first protrusion in the third direction, The first protrusion is configured to bear the weight of the developer cartridge when the first protrusion is supported by a support surface of a first side plate of the drum unit. The first pressure receiving surface is configured to receive a pressing force in the third direction from a pressing member of the first side plate of the drum unit, the pressing force being directed from the covering surface toward the exposed surface.

16. The developer cartridge according to claim 15, wherein, It further includes a first ring that is rotatable about the first protrusion.

17. The developer cartridge according to claim 16, wherein, It further includes a second ring that is rotatable about the second protrusion.

18. The developer cartridge according to any one of claims 15 to 17, characterized in that, The first protrusion is closer to the developing roller than to the second end of the housing in the first direction.

19. The developer cartridge according to any one of claims 15 to 17, characterized in that, The first pressure receiving surface extends beyond at least a part of the first outer surface of the housing in the third direction.

20. The developer cartridge according to any one of claims 15 to 17, characterized in that, It further includes: A coupler that extends from the first outer surface of the housing in the second direction, the coupler being rotatable about a coupler axis extending in the second direction, and the coupler axis being located between the developing roller and the first protrusion in the first direction.

21. The developer cartridge according to any one of claims 15 to 17, characterized in that, It further includes a coupler that extends from the first outer surface of the housing in the second direction, the coupler being rotatable about a coupler axis extending in the second direction; wherein the first protrusion is located between the coupler axis and the second protrusion in the first direction and the third direction.

22. The developer cartridge according to any one of claims 15 to 17, characterized in that, The first direction is different from the third direction.

23. The developer cartridge according to any one of claims 15 to 17, characterized in that, The developer cartridge can be attached to the drum unit in the first direction.

24. The developer cartridge according to any one of claims 15 to 17, wherein The second protrusion is configured to receive a pressing force directed from the second end of the housing in the first direction toward the first end of the housing in the first direction.

25. The developer cartridge according to claim 24, wherein, The developer cartridge is configured to pivot about the first protrusion in response to the second protrusion receiving the pressing force directed from the second end of the housing in the first direction toward the first end of the housing in the first direction.

26. The developer cartridge according to claim 24, wherein, The second protrusion is configured to receive the pressing force directed from the second end of the housing in the first direction toward the first end of the housing in the first direction from a locking lever of the drum unit.

Images