Developer cartridge

Abstract

To provide a developing cartridge with a structure including fewer components.SOLUTION: This developing cartridge includes a development electrode 60B, a first lever 110B, and a holder 120B. The holder 120B prevents the first lever 110B from being extracted from one side to the other side in a third direction. The first lever 110B stops the rotation of the development electrode 60B from one side to the other side in the third direction. Thus, it is unnecessary to provide a component to stop the rotation of the development electrode 60B from one side to the other side in the third direction besides the first lever 110B and the holder 120B. Thereby, the number of components of the developing cartridge can be reduced.SELECTED DRAWING: Figure 15

Description

[Technical Field]

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

[0002] Electrophotographic image forming apparatuses such as laser printers and LED printers are known. A developer cartridge is used in the image forming apparatus. The developer cartridge has a developer roller for supplying developer. A conventional image forming apparatus is described in, for example, Patent Document 1.

[0003] The developer cartridge in Patent Document 1 is attached to a drum cartridge. The drum cartridge has a photosensitive drum. When the developer cartridge is attached to the drum cartridge, the photosensitive drum and the developer roller come into contact with each other. Then, the drum cartridge with the attached developer cartridge is attached to an image forming apparatus. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-54058 Summary of the Invention [Problem to be solved by the invention]

[0005] The developer cartridge has a member for positioning the developer roller relative to the photosensitive drum. The developer cartridge also has a developer electrode for supplying a bias voltage to the shaft of the developer roller. The developer cartridge also has a member that receives a pressing force when the developer roller is separated from the photosensitive drum. However, if the member for positioning the developer roller, the developer electrode that supplies a bias voltage to the shaft of the developer roller, and the member that receives the pressing force when the developer roller is separated are provided separately, the number of parts in the developer cartridge increases.

[0006] An object of the present disclosure is to provide a structure that can reduce the number of parts in a developing cartridge. [Means for solving the problem]

[0007] The first disclosure of the present application is a developer cartridge comprising: a developer roller having a developer roller shaft extending in a first direction; a casing capable of containing developer, the casing having the developer roller positioned at one end in a second direction intersecting the first direction; a developer electrode having a first end electrically connected to the developer roller shaft and a second end farther from the developer roller shaft than the first end, the developer electrode being movable together with the casing and the developer roller, the second end being farther from the one end of the casing in the second direction than the first end, the developer electrode being rotatable about the developer roller shaft; a first lever movable relative to the casing; and a holder that holds the first lever movably relative to the casing, wherein, when holding the first lever, the holder prevents the first lever from coming out of the holder from one side to the other in a third direction intersecting the first direction and the second direction, and the first lever stops the developer electrode from rotating from one side to the other in the third direction.

[0008] The second disclosure of the present application is a developing cartridge of the first disclosure, characterized in that the holder stops the movement of the first lever from one side to the other in a third direction that intersects the first direction and the second direction.

[0009] The third disclosure of the present application is a developing cartridge according to the second disclosure, characterized in that the first lever has one end and another end separated from the one end to the other side in the third direction, the one end having a first convex portion protruding in the first direction, and the holder stops the movement of the first lever from one side to the other side in the third direction by contacting the first convex portion.

[0010] The fourth disclosure of the present application is a developer cartridge according to the third disclosure, wherein the developer electrode has a first hole extending in the third direction between the first end and the second end, into which the other end of the first lever is inserted, and the other end contacts the developer electrode to stop the rotation of the developer electrode from one side to the other side in the third direction.

[0011] The fifth disclosure of the present application is a developer cartridge according to the fourth disclosure, characterized in that the developer electrode has a lever receiving portion located inside the first hole, the first lever has a second convex portion protruding from the other end in the first direction, and the second convex portion stops the rotation of the developer electrode from one side to the other side in the third direction by contacting the lever receiving portion.

[0012] The sixth disclosure of the present application is a developer cartridge according to any one of the first to fifth disclosures, characterized in that the casing has a casing protrusion extending in the first direction, and the casing protrusion stops the developer electrode from rotating from the other side to one side in the third direction.

[0013] The seventh disclosure of the present application is a developer cartridge according to the sixth disclosure, characterized in that the developer electrode has an electrode protrusion extending in the first direction, and the casing protrusion stops the rotation of the developer electrode from the other side to one side in the third direction by contacting the electrode protrusion.

[0014] The eighth disclosure of the present application is a developer cartridge according to any one of the first to seventh disclosures, characterized in that the developer roller shaft has an annular engagement groove on its outer peripheral surface, the developer electrode has a first insertion hole into which the developer roller shaft is inserted and a wall portion protruding from a part of the periphery of the first insertion hole toward the engagement groove, and when the first lever engaged with the developer electrode is held by the holder, the wall portion is inserted into the engagement groove.

[0015] The ninth disclosure of the present application is a developer cartridge according to any one of the first to eighth disclosures, characterized in that the developer electrode is attached to one end of the developer roller shaft in the first direction, and the developer cartridge further comprises a bearing attached to the other end of the developer roller shaft in the first direction, the bearing having a third end having a second insertion hole into which the other end of the developer roller shaft is inserted, and a fourth end farther from the developer roller shaft than the third end, and is movable together with the casing and the developer roller.

[0016] The tenth disclosure of the present application is a developing cartridge according to the ninth disclosure, characterized in that the bearing has a second hole extending in the first direction between the third end and the fourth end, and a claw receiving portion located inside the second hole, and the casing has a claw portion extending in the first direction, the tip of which protrudes in a direction intersecting the first direction and engages with the claw receiving portion.

[0017] The 11th disclosure of the present application is a developing cartridge according to the 10th disclosure, characterized in that the bearing is rotatable about the developing roller shaft, and the claw portion stops the rotation of the bearing by contacting the bearing.

[0018] The twelfth disclosure of the present application is a developing cartridge according to any one of the ninth to eleventh disclosures, characterized in that the developing cartridge is used for a drum cartridge having a photosensitive drum, the drum cartridge has a separating lever that is rotatable about an axis extending in the first direction, and the bearing has a pressurized protrusion that protrudes in a direction away from the casing and is capable of contacting the separating lever. [Effects of the Invention]

[0019] According to the first to twelfth disclosures of the present application, the holder stops the movement of the first lever from one side to the other in the third direction. The first lever also stops the rotation of the developing electrode from one side to the other in the third direction. Therefore, there is no need to provide a component separate from the first lever and the holder for stopping the rotation of the developing electrode from one side to the other in the third direction. This reduces the number of components in the developing cartridge.

[0020] Furthermore, according to the eighth disclosure of the present application, when the first lever engaged with the developer electrode is not held by the holder, the developer roller shaft can be inserted into the first insertion hole. On the other hand, when the first lever engaged with the developer electrode is held by the holder, the wall portion is inserted into the engagement groove. Therefore, when the developer cartridge is manufactured, the developer roller shaft can be inserted into the developer electrode, and when the developer cartridge is used, the developer electrode can be prevented from coming off the developer roller shaft.

[0021] According to the tenth disclosure of the present application, the bearing is held by the claws extending from the casing in the first direction, thereby making it possible to hold the bearing without providing an engagement groove in the developing roller shaft.

[0022] Furthermore, according to the eleventh disclosure of the present application, there is no need to provide a component for stopping the rotation of the bearing apart from the claw portion. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a perspective view of a developing cartridge and a drum cartridge. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is an exploded perspective view of the developing cartridge in the vicinity of a first outer surface of the casing. [Figure 5] 10 is an exploded perspective view of the developing cartridge in the vicinity of a second outer surface of the casing. FIG. [Figure 6]FIG. 10 is a view showing the state when the developing cartridge is mounted to the drum cartridge, as viewed from one side in the first direction. [Figure 7] FIG. 10 is a view showing the state when the developing cartridge is mounted to the drum cartridge, as viewed from one side in the first direction. [Figure 8] FIG. 10 is a view showing the state when the developing cartridge is mounted to the drum cartridge, as viewed from one side in the first direction. [Figure 9] 3 is a cross-sectional view of the developing cartridge and the drum cartridge in a state where the developing cartridge is attached to the drum cartridge. FIG. [Figure 10] 10 is a cross-sectional view of the developer cartridge and the drum cartridge during the separating operation. FIG. [Figure 11] 4 is a cross-sectional view of the developing cartridge and the drum cartridge when the developing cartridge is being removed from the drum cartridge. FIG. [Figure 12] FIG. 2 is a perspective view of a developing cartridge and a drum cartridge. [Figure 13] FIG. 2 is a perspective view of a developing cartridge and a drum cartridge. [Figure 14] FIG. 2 is a perspective view of a developing cartridge and a drum cartridge. [Figure 15] 2 is a perspective view of the developing cartridge in the vicinity of a first outer surface of the casing. FIG. [Figure 16] FIG. 2 is an exploded perspective view of the developing cartridge in the vicinity of a first outer surface of the casing. [Figure 17] 10 is a perspective view of the developing cartridge in the vicinity of a second outer surface of the casing. FIG. [Figure 18] 10 is an exploded perspective view of the developing cartridge in the vicinity of a second outer surface of the casing. FIG. [Figure 19] 4 is a diagram showing a cross section of a first bearing and a side view of a first lever. FIG. [Figure 20] 10A and 10B are diagrams illustrating a state in which a first bearing, a first lever, and a holder are attached to a developing cartridge. [Figure 21]10A and 10B are diagrams illustrating a state in which a first bearing, a first lever, and a holder are attached to a developing cartridge. [Figure 22] FIG. 4 is a partial cross-sectional view of the developing cartridge in the vicinity of a second bearing. [Figure 23] FIG. 10 is a view showing the state when the developing cartridge is mounted to the drum cartridge, as viewed from one side in the first direction. [Figure 24] FIG. 10 is a view showing the state when the developing cartridge is mounted to the drum cartridge, as viewed from one side in the first direction. [Figure 25] FIG. 10 is a view of the developer cartridge and drum cartridge after installation, viewed from one side in the first direction. [Figure 26] FIG. 10 is a view of the developing cartridge and the drum cartridge during the separating operation, as viewed from one side in the first direction. [Figure 27] FIG. 10 is a view of the developer cartridge and drum cartridge after installation, viewed from the other side in the first direction. [Figure 28] 10 is a view of the developing cartridge and the drum cartridge during the separating operation, as viewed from the other side in the first direction. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0025] In the following description, the direction in which the developing roller 30 of the developing cartridge 1 extends will be referred to as the "first direction." Furthermore, the direction in which the agitator 20 of the developing cartridge 1 and the developing roller 30 are aligned will be referred to as the "second direction." The first direction and the second direction intersect (preferably perpendicular to) each other.

[0026] 1. First Embodiment <1-1. Overview of developing cartridges and drum cartridges> FIG. 1 is a perspective view of a developer cartridge 1 and a drum cartridge 2. FIG. 1 shows the developer cartridge 1 attached to the drum cartridge 2. The developer cartridge 1 and the drum cartridge 2 are used in an electrophotographic image forming apparatus. The image forming apparatus is, for example, a laser printer or an LED printer.

[0027] As shown in FIG. 1, a developer cartridge 1 is used together with a drum cartridge 2. The developer cartridge 1 is attachable to the drum cartridge 2. The developer cartridge 1 is attached to the image forming device while attached to the drum cartridge 2. The image forming device can accommodate, for example, four developer cartridges 1. The four developer cartridges 1 contain developers (e.g., toner) of different colors (e.g., cyan, magenta, yellow, and black). The image forming device forms an image on the recording surface of printing paper using the developer supplied from the developer cartridges 1. However, the number of developer cartridges 1 that can be attached to the image forming device may be one to three, or may be five or more.

[0028] <1-2. Structure of the developing cartridge> 2 and 3 are perspective views of the developer cartridge 1. Fig. 4 is an exploded perspective view of the developer cartridge 1 in the vicinity of the first outer surface 11 of the casing 10. Fig. 5 is an exploded perspective view of the developer cartridge 1 in the vicinity of the second outer surface 12 of the casing 10. As shown in Figs. 1 to 5, the developer cartridge 1 includes a casing 10, an agitator 20, a developing roller 30, a supply roller 40, a gear unit 50, a first bearing 60, a first lever 110, a holder 120, a second bearing 70, and a second lever 130.

[0029] The casing 10 is a housing capable of containing a developer. The casing 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 casing 10 in the first direction. The second outer surface 12 is located at the other end of the casing 10 in the first direction. The first outer surface 11 and the second outer surface 12 are spaced apart from each other in the first direction. The casing 10 extends in the first direction between the first outer surface 11 and the second outer surface 12, and also extends in the second direction.

[0030] A storage chamber 13 is provided inside the casing 10. The developer is stored in the storage chamber 13. The casing 10 also has an opening 14. The opening 14 is located at one end of the casing 10 in the second direction. The external space of the casing 10 and the storage chamber 13 communicate with each other via the opening 14. The casing 10 may have a handle on the outer surface of the other end in the second direction.

[0031] The agitator 20 has an agitator shaft 21 and blades 22. The agitator shaft 21 extends along the first direction. The blades 22 extend from the agitator shaft 21 toward the inner surface of the casing 10. A portion of the agitator shaft 21 and the blades 22 are disposed within the storage chamber 13 of the casing 10. An agitator gear (not shown) included in the gear unit 50 is attached to the end of the agitator shaft 21 in the first direction. The agitator shaft 21 is fixed to the agitator gear so as not to rotate relative to it. When the agitator gear rotates, the agitator shaft 21 and the blades 22 rotate about a rotation axis extending in the first direction. The rotation of the blades 22 agitates the developer in the storage chamber 13.

[0032] The developing roller 30 is a roller that can rotate about a rotation axis A1 that extends in the first direction. The developing roller 30 is located in the opening 14 of the casing 10. That is, the developing roller 30 is located at one end of the casing 10 in the second direction. The developing roller 30 has a developing roller main body 31 and a developing roller shaft 32. The developing roller main body 31 is a cylindrical member that extends in the first direction. The developing roller main body 31 is made of, for example, elastic rubber. The developing roller shaft 32 is a cylindrical member that penetrates the developing roller main body 31 and extends in the first direction. The developing roller shaft 32 is conductive. The developing roller shaft 32 is made of a metal or a conductive resin.

[0033] The developing roller main body 31 is fixed to the developing roller shaft 32 so as not to rotate relative to it. A developing roller gear 51 included in a gear unit 50 is attached to the end of the developing roller shaft 32 in the first direction. The developing roller shaft 32 is fixed to the developing roller gear 51 so as not to rotate relative to it. Therefore, when the developing roller gear 51 rotates, the developing roller shaft 32 also rotates, and the developing roller main body 31 rotates together with the developing roller shaft 32.

[0034] The developing roller shaft 32 does not have to penetrate the developing roller main body 31 in the first direction. For example, the developing roller shaft 32 may extend in the first direction from both ends of the developing roller main body 31 in the first direction.

[0035] The supply roller 40 is a roller that can rotate about a rotation axis that extends in the first direction. The supply roller 40 is located between the agitator 20 and the developing roller 30. The supply roller 40 has a supply roller main body 41 and a supply roller shaft 42. The supply roller main body 41 is a cylindrical member that extends in the first direction. The supply roller main body 41 is made of, for example, elastic rubber. The supply roller shaft 42 is a cylindrical member that penetrates the supply roller main body 41 and extends in the first direction.

[0036] Supply roller body 41 is fixed to supply roller shaft 42 so as not to rotate relative to it. A supply roller gear (not shown) included in gear unit 50 is attached to the end of supply roller shaft 42 in the first direction. Supply roller shaft 42 is fixed to supply roller gear so as not to rotate relative to it. Therefore, when the supply roller gear rotates, supply roller shaft 42 also rotates, and supply roller body 41 rotates together with supply roller shaft 42.

[0037] The supply roller shaft 42 does not have to penetrate the supply roller main body 41 in the first direction. For example, the supply roller shaft 42 may extend in the first direction from both ends of the supply roller main body 41 in the first direction.

[0038] When the developer cartridge 1 receives a driving force, developer is supplied from the storage chamber 13 in the casing 10 to the outer circumferential surface of the developer roller 30 via the supply roller 40. At this time, the developer is frictionally charged between the supply roller 40 and the developer roller 30. Meanwhile, a bias voltage is applied to the developer roller shaft 32 of the developer roller 30. Therefore, the developer is attracted to the outer circumferential surface of the developer roller body 31 by the electrostatic force between the developer roller shaft 32 and the developer.

[0039] The developing cartridge 1 also has a layer thickness regulating blade (not shown). The layer thickness regulating blade shapes the developer supplied to the outer peripheral surface of the developing roller main body 31 to a uniform thickness. The developer on the outer peripheral surface of the developing roller main body 31 is then supplied to a photosensitive drum 92 (described later) of the drum cartridge 2. At this time, the developer moves from the developing roller main body 31 to the photosensitive drum 92 in accordance with the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 92. As a result, the electrostatic latent image is visualized on the outer peripheral surface of the photosensitive drum 92.

[0040] The gear portion 50 is located on the second outer surface 12 of the casing 10. As shown in FIG. 5 , the gear portion 50 has the above-mentioned agitator gear, developing roller gear 51, and supply roller gear, as well as multiple idle gears, a coupling 52, and a gear cover 53. The gear cover 53, together with the casing 10, constitutes the housing of the developer cartridge 1. The gear cover 53 is fixed to the second outer surface 12 of the casing 10, for example, by screws. At least some of the multiple gears are located between the second outer surface 12 and the gear cover 53.

[0041] The gear cover 53 has a cylindrical collar 531 that protrudes in the first direction. The coupling 52 is housed inside the collar 531. The coupling 52 has an engagement portion 521 that is recessed in the first direction. The engagement portion 521 is exposed from the gear cover 53. When the developer cartridge 1 attached to the drum cartridge 2 is attached to the image forming apparatus, the drive shaft of the image forming apparatus is connected to the engagement portion 521 of the coupling 52. Then, rotation of the drive shaft is transmitted via the coupling 52 to the agitator gear, the multiple idle gears, the developing roller gear 51, and the supply roller gear.

[0042] The gears included in the gear unit 50 may transmit a rotational force by meshing of teeth, or may transmit a rotational force by friction.

[0043] The first bearing 60 is located on the first outer surface 11 of the casing 10. The first bearing 60 rotatably supports one end of the developing roller shaft 32 in the first direction. As shown in FIG. 4 , the first bearing 60 has a first end 61 and a second end 62. The second end 62 is farther away from the developing roller shaft 32 than the first end 61. The second end 62 is farther away in the second direction from one end of the casing 10 in the second direction than the first end 61. The first bearing 60 extends along the first outer surface 11 of the casing 10 between the first end 61 and the second end 62.

[0044] The first bearing 60 has a first arm 63 and a second arm 64. The second arm 64 is farther from the developing roller shaft 32 than the first arm 63. Furthermore, the second arm 64 is farther from one end of the casing 10 in the second direction than the first arm 63. The first arm 63 has the first end 61 described above. The second arm 64 has the second end 62 described above. The first arm 63 extends, for example, linearly along the first outer surface 11 of the casing 10. The second arm 64 extends, for example, linearly along the first outer surface 11 of the casing 10. However, the first arm 63 is bent with respect to the second arm 64. The angle formed between the first arm 63 and the second arm 64 is an obtuse angle.

[0045] In this embodiment, the first arm 63 and the second arm 64 are integrally formed. However, the first arm 63 and the second arm 64 may be separate parts. In that case, it is sufficient that the first arm 63 and the second arm 64 are fixed to each other.

[0046] The first bearing 60 has a first insertion hole 65. The first insertion hole 65 extends in the first direction at a first end 61 of the first bearing 60. The first insertion hole 65 may be a through-hole that penetrates the first end 61 in the first direction, or it may not penetrate the first end 61. The first insertion hole 65 has a cylindrical inner circumferential surface. One end of the developing roller shaft 32 in the first direction is inserted into the first insertion hole 65. As a result, the first bearing 60 is attached to one end of the developing roller shaft 32 in the first direction. The one end of the developing roller shaft 32 in the first direction is rotatably supported about a rotation axis A1 that extends in the first direction. The first bearing 60 is also rotatable about the developing roller shaft 32 with respect to the casing 10. Specifically, the second end 62 is rotatable about the rotation axis A1 with respect to the first end 61.

[0047] The first bearing 60 is a conductive development electrode. The first bearing 60 is made of, for example, a conductive resin. However, the first bearing 60 may also be made of a metal. A first end 61 of the first bearing 60 contacts one end of the developing roller shaft 32 in the first direction. Therefore, the first end 61 of the first bearing 60 is electrically connected to the developing roller shaft 32.

[0048] The first bearing 60 also has a first hole 67. The first hole 67 extends in the second direction between the first end 61 and the second end 62. The first hole 67 also penetrates the first bearing 60 in the rotation direction about the rotation axis A1. However, the first hole 67 does not have to penetrate the first bearing 60. The other end 112 of the first lever 110, which will be described later, is inserted into the first hole 67.

[0049] The first lever 110 is located on the first outer surface 11 of the casing 10. As shown in FIG. 4 , the first lever 110 has one end 111, another end 112, and a cam surface 113. The one end 111 is located at one end of the first lever 110 in a third direction intersecting the first direction and the second direction. The other end 112 is located at the other end of the first lever 110 in the third direction. The cam surface 113 is located between the one end 111 and the other end 112 in the third direction. The one end 111 of the first lever 110 has a first protrusion 114. The first protrusion 114 protrudes from the one end 111 of the first lever 110 in the first direction. The other end 112 of the first lever 110 has a second protrusion 115. The second protrusion 115 protrudes from the other end 112 of the first lever 110 in the first direction.

[0050] The first lever 110 is movable relative to the casing 10. When the developing cartridge 1 is attached to the drum cartridge 2, the cam surface 113 can come into contact with a drum frame 91 (described later) of the drum cartridge 2. The first lever 110 is rotatable about the cam surface 113 between a first position and a second position.

[0051] The other end 112 of the first lever 110 is inserted into the first hole 67 of the first bearing 60. The other end 112 of the first lever 110 is connected to the inner surface of the first hole 67 of the first bearing 60. Specifically, the first bearing 60 has an engagement surface 69 (see FIG. 11 ) on the inner surface of the first hole 67. The engagement surface 69 and the second protrusion 115 of the first lever 110 face each other in the third direction. That is, the second protrusion 115 of the first lever 110 engages with the engagement surface 69 of the first bearing 60. This prevents the first lever 110 from slipping out of the first bearing 60 to one side in the third direction. Furthermore, the rotation range of the first bearing 60 around the rotation axis A1 is restricted.

[0052] The holder 120 is located on the first outer surface 11 of the casing 10. The holder 120 is fixed to the first outer surface 11 of the casing 10, for example, by screws. A portion of the first lever 110 is located between the first outer surface 11 and the holder 120. The first protrusion 114 of the first lever 110 is located on one side of the holder 120 in the third direction. The second protrusion 115 of the first lever 110 is located on the other side of the holder 120 in the third direction. The first protrusion 114 and the holder 120 face each other in the third direction. This prevents the first lever 110 from slipping out of the holder 120 to the other side in the third direction. In other words, the holder 120 holds the first lever 110 movably relative to the casing 10.

[0053] The second bearing 70 is located on the second outer surface 12 of the casing 10. More specifically, the second bearing 70 is located on the outer surface of the gear cover 53. The first bearing 60 and the second bearing 70 are positioned to overlap in the first direction. The second bearing 70 rotatably supports the other end of the developing roller shaft 32 in the first direction. As shown in FIG. 5 , the second bearing 70 has a third end 71 and a fourth end 72. The fourth end 72 is farther from the developing roller shaft 32 than the third end 71. Furthermore, the fourth end 72 is farther from one end of the casing 10 in the second direction than the third end 71. The second bearing 70 extends along the second outer surface 12 of the casing 10 between the third end 71 and the fourth end 72.

[0054] The second bearing 70 has a third arm 73 and a fourth arm 74. The fourth arm 74 is farther from the developing roller shaft 32 than the third arm 73. Furthermore, the fourth arm 74 is farther from one end of the casing 10 in the second direction than the third arm 73. The third arm 73 has the third end 71 described above. The fourth arm 74 has the fourth end 72 described above. The third arm 73 extends, for example, linearly along the second outer surface 12 of the casing 10. The fourth arm 74 extends, for example, linearly along the second outer surface 12 of the casing 10. However, the third arm 73 is curved with respect to the fourth arm 74. The angle formed between the third arm 73 and the fourth arm 74 is an obtuse angle.

[0055] In this embodiment, the third arm 73 and the fourth arm 74 are integrally formed. However, the third arm 73 and the fourth arm 74 may be separate parts. In that case, it is sufficient that the third arm 73 and the fourth arm 74 are fixed to each other.

[0056] The second bearing 70 has a second insertion hole 75. The second insertion hole 75 extends in the first direction at the third end 71 of the second bearing 70. The second insertion hole 75 may be a through-hole that penetrates the third end 71 in the first direction, or it may not penetrate the third end 71. The second insertion hole 75 has a cylindrical inner circumferential surface. The other end of the developing roller shaft 32 in the first direction is inserted into the second insertion hole 75. This allows the second bearing 70 to be attached to the other end of the developing roller shaft 32 in the first direction. The other end of the developing roller shaft 32 in the first direction is rotatably supported about the rotation axis A1 that extends in the first direction. The second bearing 70 is also rotatable about the developing roller shaft 32 with respect to the casing 10. Specifically, the fourth end 72 is rotatable about the rotation axis A1 with respect to the third end 71.

[0057] The second bearing 70 also has a third hole 77. The third hole 77 extends in the second direction between the third end 71 and the fourth end 72. The third hole 77 also penetrates the second bearing 70 in the rotation direction about the rotation axis A1. However, the third hole 77 does not have to penetrate the second bearing 70. The other end 132 of the second lever 130, which will be described later, is inserted into the third hole 77. The first hole 67 of the first bearing 60 and the third hole 77 of the second bearing 70 are positioned to overlap in the first direction.

[0058] The second lever 130 is located on the second outer surface 12 of the casing 10. More specifically, the second bearing 70 is located on the outer surface of the gear cover 53. As shown in FIG. 5 , the second lever 130 has one end 131, the other end 132, and a cam surface 133. The one end 131 is located at one end of the second lever 130 in the third direction. The other end 132 is located at the other end of the second lever 130 in the third direction. The cam surface 133 is located between the one end 131 and the other end 132 in the third direction. In addition, the other end 132 of the second lever 130 has a third protrusion 135. The third protrusion 135 protrudes from the other end 132 of the second lever 130 in the first direction.

[0059] One end 111 of the first lever 110 and one end 131 of the second lever 130 are positioned to overlap in the first direction. The other end 112 of the first lever 110 and the other end 132 of the second lever 130 are positioned to overlap in the first direction.

[0060] The second lever 130 is movable relative to the casing 10. When the developer cartridge 1 is attached to the drum cartridge 2, the cam surface 133 can come into contact with a drum frame 91 (described later) of the drum cartridge 2. The second lever 130 is rotatable about the cam surface 133 between a third position and a fourth position.

[0061] The other end 132 of the second lever 130 is inserted into the third hole 77 of the second bearing 70. The other end 132 of the second lever 130 is connected to the inner surface of the third hole 77 of the second bearing 70. Specifically, the second bearing 70 has an engagement surface (not shown) on the inner surface of the third hole 77. This engagement surface and the third protrusion 135 of the second lever 130 face each other in the third direction. That is, the third protrusion 135 of the second lever 130 engages with the engagement surface of the second bearing 70. This prevents the second lever 130 from slipping off the second bearing 70 to one side in the third direction. Furthermore, the rotation range of the second bearing 70 around the rotation axis A1 is restricted.

[0062] As shown in FIG. 5 , the gear cover 53 has a gear cover protrusion 532 that protrudes in the first direction. The second lever 130 is located between the collar 531 of the gear cover 53 and the gear cover protrusion 532 in the second direction. This restricts movement of the second lever 130 in the second direction. The second lever 130 also extends in an arc shape along the outer circumferential surface of the collar 531 of the gear cover 53. A portion of the collar 531 is located between one end 131 and the other end 132 of the second lever 130 in the third direction. This restricts movement of the second lever 130 in the third direction.

[0063] <1-3. Structure of drum cartridge> As shown in FIG. 1, the drum cartridge 2 includes a drum frame 91 and a photosensitive drum 92. The developer cartridge 1 is attached to the drum frame 91. The photosensitive drum 92 is a cylindrical drum that is rotatable about a rotation axis that extends in a first direction. The outer peripheral surface of the photosensitive drum 92 is covered with a photosensitive material. The photosensitive drum 92 is located at one end of the drum frame 91 in the second direction. When the developer cartridge 1 is attached to the drum frame 91, the outer peripheral surface of the developer roller 30 comes into contact with the outer peripheral surface of the photosensitive drum 92.

[0064] 6 to 8 are views showing the state when the developer cartridge 1 is attached to the drum cartridge 2, viewed from one side in the first direction. Fig. 9 is a cross-sectional view of the developer cartridge 1 and the drum cartridge 2 in a state in which the developer cartridge 1 is attached to the drum cartridge 2. Note that Fig. 9 shows a cross section that is perpendicular to the first direction and passes through the first bearing 60 and the first lever 110.

[0065] As shown in FIG. 9 , the drum cartridge 2 has a first guide surface 93 and a second guide surface 94. The first guide surface 93 and the second guide surface 94 are located at one end of the drum frame 91 in the first direction. The first guide surface 93 and the second guide surface 94 are spaced apart in the rotation direction around the rotation axis of the photosensitive drum 92. The drum cartridge 2 also has a third guide surface (not shown) and a fourth guide surface (not shown) similar to the first guide surface 93 and the second guide surface 94 at the other end of the drum frame 91 in the first direction.

[0066] As shown in FIG. 9 , the drum cartridge 2 includes a first pressing member 95 and a first coil spring 96. The first pressing member 95 and the first coil spring 96 are conductive. The first pressing member 95 is made of, for example, conductive resin. The first coil spring 96 is made of, for example, metal. The first pressing member 95 and the first coil spring 96 are located at one end of the drum frame 91 in the first direction. The first coil spring 96 is an elastic member that can expand and contract in the second direction. One end of the first coil spring 96 in the second direction is connected to the first pressing member 95. The other end of the first coil spring 96 in the second direction is connected to the drum frame 91. When the developer cartridge 1 is installed in the drum cartridge 2, the first pressing member 95 presses the second end 62 of the first bearing 60 toward the photosensitive drum 92 by the elastic force of the first coil spring 96.

[0067] The drum cartridge 2 also includes a second pressing member (not shown) and a second coil spring (not shown). The second pressing member and the second coil spring are located at the other end of the drum frame 91 in the first direction. When the developer cartridge 1 is attached to the drum cartridge 2, the second pressing member presses the fourth end 72 of the second bearing 70 toward the photosensitive drum 92 due to the elastic force of the second coil spring.

[0068] The drum cartridge 2 may include other types of elastic members instead of the first coil spring 96 and the second coil spring. For example, the drum cartridge 2 may include, as the elastic member, a spring other than a coil spring, such as a torsion spring or a leaf spring, or rubber.

[0069] As shown in FIGS. 6 to 9, the drum cartridge 2 also includes a first release lever 97. The first release lever 97 is located at one end of the drum frame 91 in the first direction. The first release lever 97 is rotatable about an axis extending in the first direction. The drum cartridge 2 also includes a second release lever (not shown). The second release lever is located at the other end of the drum frame 91 in the first direction. The second release lever is rotatable about an axis extending in the first direction.

[0070] <1-4. Installing the developing cartridge> When the developer cartridge 1 is attached to the drum cartridge 2, as shown in FIGS. 6 to 9, the developer cartridge 1 moves relative to the drum cartridge 2 so that the developer roller 30 approaches the photosensitive drum 92. At this time, as shown in FIGS. 6 to 9, the second end 62 of the first bearing 60 comes into contact with the first release lever 97 and moves along the first release lever 97. As a result, the first bearing 60 rotates about the rotation axis A1. Similarly, the third end 71 of the second bearing 70 comes into contact with the second release lever and moves along the second release lever. As a result, the second bearing 70 rotates about the rotation axis A1.

[0071] In this way, when the developer cartridge 1 is attached to the drum cartridge 2, the first bearing 60 and the second bearing 70 rotate about the rotation axis A1 of the developer roller 30. Therefore, the first bearing 60 can be disposed between the photosensitive drum 92 and the first pressing member 95, and the second bearing 70 can be disposed between the photosensitive drum 92 and the second pressing member, without rotating the casing 10 relative to the drum frame 91. Therefore, a user of the image forming apparatus can move the developer roller 30 closer to the photosensitive drum 92 without rotating the casing 10.

[0072] When the first bearing 60 is disposed between the photosensitive drum 92 and the first pressing member 95, the first pressing member 95 comes into contact with the second end 62 of the first bearing 60. Then, due to the elastic force of the first coil spring 96, the first pressing member 95 presses the second end 62 of the first bearing 60 toward the photosensitive drum 92. Then, as shown in FIG. 9 , the first end 61 of the first bearing 60 comes into contact with the first guide surface 93, and the other portion of the first bearing 60 comes into contact with the second guide surface 94. This fixes the position of the first bearing 60 relative to the drum frame 91.

[0073] Similarly, the second pressing member presses the fourth end 72 of the second bearing 70 toward the photosensitive drum 92. As a result, the third end 71 of the second bearing 70 contacts the third guide surface, and the other portion of the second bearing 70 contacts the fourth guide surface. This fixes the position of the second bearing 70 relative to the drum frame 91.

[0074] Furthermore, with the positions of the first bearing 60 and the second bearing 70 fixed relative to the drum frame 91, the first pressing member 95 presses the first bearing 60, and the second pressing member presses the second bearing 70. This causes the outer peripheral surface of the developing roller 30 to come into contact with the outer peripheral surface of the photosensitive drum 92. The developing roller 30 is then pressed against the photosensitive drum 92.

[0075] As described above, in this embodiment, the first bearing 60 has a first end 61 and a second end 62, and the second end 62 is rotatable relative to the first end 61. Furthermore, the second bearing 70 has a third end 71 and a fourth end 72, and the fourth end 72 is rotatable relative to the third end 71. Therefore, the developing roller 30 can be positioned relative to the photosensitive drum 92 by utilizing the first end 61 and the second end 62 of the first bearing 60 and the third end 71 and the fourth end 72 of the second bearing 70.

[0076] In this embodiment, when the developer cartridge 1 is attached to the drum cartridge 2, the first bearing 60 and the second bearing 70 rotate about the rotation axis A1. Similarly, when the developer cartridge 1 is removed from the drum cartridge 2, the first bearing 60 and the second bearing 70 rotate about the rotation axis A1. Therefore, the developer cartridge 1 can be smoothly attached to and removed from the drum cartridge 2 by rotating the first bearing 60 and the second bearing 70 without rotating the casing 10.

[0077] <1-5. Voltage supply> The first pressing member 95 and the first coil spring 96 are conductive. The first pressing member 95 is made of, for example, a conductive resin. The first coil spring 96 is made of, for example, a metal. The drum cartridge 2 also includes an electrode terminal 98 that is in electrical contact with the first coil spring 96. As shown in FIGS. 6 to 8 , the electrode terminal 98 is exposed on the outer surface of the drum frame 91. As described above, the developing roller shaft 32 and the first bearing 60 are also conductive. Therefore, when the developing cartridge 1 is attached to the drum cartridge 2 and the first pressing member 95 contacts the first bearing 60, the electrode terminal 98, the first coil spring 96, the first pressing member 95, the first bearing 60, and the developing roller shaft 32 are electrically connected to one another.

[0078] When the developer cartridge 1 attached to the drum cartridge 2 is installed in an image forming apparatus, the electrode terminal of the image forming apparatus comes into contact with the electrode terminal 98 of the drum cartridge 2. Then, a bias voltage is supplied from the image forming apparatus to the developer roller shaft 32 via the electrode terminal 98, the first coil spring 96, the first pressing member 95, and the first bearing 60. As a result, the developer is attracted to the outer circumferential surface of the developer roller body 31 by electrostatic force due to the bias voltage.

[0079] In this manner, in this embodiment, the bias voltage is supplied to the first bearing 60 of the developer cartridge 1 via the first pressing member 95 of the drum cartridge 2. In this manner, the number of parts of the drum cartridge 2 can be reduced compared to when a conductive part for supplying voltage to the first bearing 60 is provided separately from the first pressing member 95. Therefore, the drum cartridge 2 can be made smaller.

[0080] Furthermore, the first bearing 60 of this embodiment performs multiple functions: (1) a function as a bearing that rotatably supports the developing roller shaft 32, (2) a function as a positioning member that positions the developing roller 30 with respect to the photosensitive drum 92 when the developing cartridge 1 is attached to the drum cartridge 2, and (3) a function as a developing electrode that supplies a bias voltage to the developing roller shaft 32. Therefore, compared to when these functions are realized by separate members, the number of parts of the developing cartridge 1 can be reduced and the developing cartridge 1 can be made smaller.

[0081] <1-6. About the separation operation> After the developer cartridge 1 is installed in the image forming apparatus while attached to the drum cartridge 2, it can perform a separation operation by a driving force supplied from the image forming apparatus. The separation operation is an operation for temporarily separating the developer roller 30 from the photosensitive drum 92. For example, when monochrome printing is performed in the image forming apparatus, the developer cartridges 1 of each color other than black perform the separation operation. However, there may be cases where only the black developer cartridge 1 performs the separation operation.

[0082] As shown in FIG. 9 , when the developer cartridge 1 is attached to the drum cartridge 2, the developer cartridge 1 is positioned at a contact position where the developer roller 30 contacts the photosensitive drum 92. The position of the first lever 110 at this time is the first position. In the first position, the other end 112 of the first lever 110 is separated from the inner surface 670 of the first hole 67 of the first bearing 60. Therefore, the other end 112 of the first lever 110 does not press against the inner surface 670 of the first hole 67. The cam surface 113 of the first lever 110 is in contact with the drum frame 91. The position of the second lever 130 at this time is the third position. In the third position, the other end 132 of the second lever 130 is separated from the inner surface of the third hole 77 of the second bearing 70. Therefore, the other end 132 of the second lever 130 does not press against the inner surface of the third hole 77 of the second bearing 70. In addition, the cam surface 133 of the second lever 130 is in contact with the drum frame 91 .

[0083] 10 is a cross-sectional view of the developer cartridge 1 and the drum cartridge 2 during the separating operation. Note that Fig. 10 shows a cross section perpendicular to the first direction and passing through the first bearing 60 and the first lever 110.

[0084] When performing the separation operation, the image forming apparatus applies a driving force to one end 111 of the first lever 110. Specifically, the image forming apparatus operates a drive lever (not shown). This causes the drive lever to press the one end 111 of the first lever 110, as indicated by the dashed arrow in FIG. 10 . This causes the first lever 110 to rotate from the first position to the second position around the cam surface 113. At this time, the other end 112 of the first lever 110 moves in a direction away from the photosensitive drum 92 and presses the inner surface 670 of the first hole 67 of the first bearing 60. Specifically, the other end 112 of the first lever 110 presses the second end 62 of the first bearing 60 in a direction away from the developing roller 30, against the pressing force of the first pressing member 95. As a result, the first bearing 60 moves together with the other end 112 of the first lever 110 in a direction away from the photosensitive drum 92 .

[0085] Furthermore, when the image forming apparatus performs the separation operation, it applies a driving force to one end 131 of the second lever 130. Specifically, the image forming apparatus operates another driving lever (not shown). This causes the driving lever to press one end 131 of the second lever 130. As a result, the second lever 130 rotates from the third position to the fourth position around the cam surface 133. At this time, the other end 132 of the second lever 130 moves in a direction away from the photosensitive drum 92 and presses the inner surface of the third hole 77 of the second bearing 70. Specifically, the other end 132 of the second lever 130 presses the fourth end 72 of the second bearing 70 in a direction away from the developing roller 30 against the pressing force of the second pressing member. As a result, the second bearing 70 moves together with the other end 132 of the second lever 130 in a direction away from the photosensitive drum 92.

[0086] As a result, the casing 10 and the developing roller 30 move together with the first bearing 60 and the second bearing 70 in a direction away from the photosensitive drum 92. As a result, the outer circumferential surface of the developing roller 30 moves away from the outer circumferential surface of the photosensitive drum 92. In other words, the developing cartridge 1 moves from the contact position to the separated position relative to the drum cartridge 2.

[0087] Thus, in this embodiment, in response to the force that one end 111 of the first lever 110 receives from the drive lever of the image forming apparatus, the other end 112 of the first lever 110 presses the inner surface 670 of the first hole 67 of the first bearing 60. This makes it possible to apply a force to move the developer cartridge 1 from the contact position to the separated position. In other words, the driving force supplied from the image forming apparatus can be transmitted to the first bearing 60 by the first lever 110, which has the one end 111 that functions as a force point, the other end 112 that functions as a point of application, and the cam surface 113 that functions as a fulcrum.

[0088] Furthermore, in response to the force that one end 131 of the second lever 130 receives from the drive lever of the image forming apparatus, the other end 132 of the second lever 130 presses the inner surface of the third hole 77 of the second bearing 70. This makes it possible to apply a force to move the developer cartridge 1 from the contact position to the separated position. That is, the drive force supplied from the image forming apparatus can be transmitted to the second bearing 70 by the second lever 130, which has the one end 131 that functions as a force point, the other end 132 that functions as a point of application, and the cam surface 133 that functions as a fulcrum.

[0089] In other words, the driving force supplied from the image forming apparatus is transmitted to the first bearing 60 and the second bearing 70 of the developer cartridge 1 without passing through the drum cartridge 2. In this way, there is no need to provide the drum cartridge 2 with any parts that relay the driving force. This allows the number of parts in the drum cartridge 2 to be reduced, and therefore the drum cartridge 2 can be made more compact.

[0090] Furthermore, in this developing cartridge 1, one end 111 of the first lever 110 has a first protrusion 114 that protrudes in the first direction. Therefore, the surface area of ​​the one end 111 of the first lever 110 is larger than if the first protrusion 114 were not present. Therefore, during the separating operation, the drive lever of the image forming apparatus can stably press the one end 111 of the first lever 110. This stabilizes the separating operation of the image forming apparatus. Note that, like the first lever 110, the one end 131 of the second lever 130 may also have a protrusion that protrudes in the first direction.

[0091] Furthermore, in this developer cartridge 1, the first bearing 60 and the second bearing 70 that support the developing roller shaft 32 receive a pressing force during the separating operation. This allows the number of parts in the developer cartridge 1 to be reduced compared to when a member that receives the pressing force during the separating operation is provided separately from the first bearing 60 and the second bearing 70. This allows the developer cartridge 1 to be made smaller.

[0092] Furthermore, the first bearing 60 is rotatable about the rotation axis A1. Therefore, the first lever 110 can press the inner surface 670 of the first hole 67 of the first bearing 60 in an optimal direction. Similarly, the second bearing 70 is also rotatable about the rotation axis A1. Therefore, the second lever 130 can press the inner surface 670 of the third hole 77 of the second bearing 70 in an optimal direction.

[0093] Furthermore, when the developer cartridge 1 moves from the contact position to the separated position, the first bearing 60 moves along the second guide surface 94. Furthermore, the second bearing 70 moves along the fourth guide surface. This allows the first lever 110 to press the first bearing 60 while maintaining the position of the first bearing 60 centered on the rotation axis A1. Furthermore, the second lever 130 can press the second bearing 70 while maintaining the position of the second bearing 70 centered on the rotation axis A1.

[0094] <1-7. Removing the developing cartridge> Figure 11 is a cross-sectional view of the developer cartridge 1 and the drum cartridge 2 when the developer cartridge 1 is being removed from the drum cartridge 2. Note that Figure 11 shows a cross section that is perpendicular to the first direction and passes through the first bearing 60 and the first lever 110.

[0095] When removing the developer cartridge 1 from the drum cartridge 2, the user presses the first release lever 97 and the second release lever. This causes the first release lever 97 and the second release lever to rotate about an axis extending in the first direction. As a result, the first release lever 97 presses the first lever 110 toward one side in the third direction. Furthermore, the second release lever presses the second lever 130 toward one side in the third direction. Furthermore, the other end 112 of the first lever 110 contacts the engagement surface 69 of the first bearing 60 and presses the engagement surface 69 toward one side in the third direction. Furthermore, the other end 132 of the second lever 130 contacts the engagement surface of the second bearing 70 and presses the engagement surface 79 toward one side in the third direction.

[0096] As a result, the first bearing 60 comes out from between the photosensitive drum 92 and the first pressing member 95 to one side in the third direction. Also, the second bearing 70 comes out from between the photosensitive drum 92 and the second pressing member to one side in the third direction. As a result, the developer cartridge 1 can be removed from the drum cartridge 2.

[0097] 2. Second Embodiment <2-1. Overview of Developer Cartridges and Drum Cartridges> 12 to 14 are perspective views of the developer cartridge 1B and the drum cartridge 2B. FIG. 12 shows the developer cartridge 1B attached to the drum cartridge 2B. FIGS. 13 and 14 show the developer cartridge 1B not attached to the drum cartridge 2B. The developer cartridge 1B and the drum cartridge 2B are used in an electrophotographic image forming apparatus. The image forming apparatus is, for example, a laser printer or an LED printer.

[0098] As shown in Figures 12 to 14, the developer cartridge 1B is used together with the drum cartridge 2B. The developer cartridge 1B is attachable to the drum cartridge 2B. The developer cartridge 1B is attached to the image forming device in a state where it is attached to the drum cartridge 2B. The image forming device can attach, for example, four developer cartridges 1B. The four developer cartridges 1B contain developers (e.g., toner) of different colors (e.g., cyan, magenta, yellow, and black). The image forming device forms an image on the recording surface of printing paper using the developer supplied from the developer cartridges 1B. However, the number of developer cartridges 1B that can be attached to the image forming device may be one to three, or may be five or more.

[0099] <2-2. Structure of the developing cartridge> Fig. 15 is a perspective view of the developer cartridge 1B in the vicinity of the first outer surface 11B of the casing 10B. Fig. 16 is an exploded perspective view of the developer cartridge 1B in the vicinity of the first outer surface 11B of the casing 10B. Fig. 17 is a perspective view of the developer cartridge 1B in the vicinity of the second outer surface 12B of the casing 10B. Fig. 18 is an exploded perspective view of the developer cartridge 1B in the vicinity of the second outer surface 12B of the casing 10B.

[0100] As shown in FIGS. 12 to 18, the developing cartridge 1B includes a casing 10B, an agitator 20B, a developing roller 30B, a gear portion 50B, a first bearing 60B, a first lever 110B, a holder 120B, and a second bearing 70B.

[0101] The casing 10B is a housing capable of containing a developer. The casing 10B has a first outer surface 11B and a second outer surface 12B. The first outer surface 11B is located at one end of the casing 10B in the first direction. The second outer surface 12B is located at the other end of the casing 10B in the first direction. The first outer surface 11B and the second outer surface 12B are spaced apart from each other in the first direction. The casing 10B extends in the first direction between the first outer surface 11B and the second outer surface 12B, and also extends in the second direction.

[0102] A storage chamber 13B is provided inside the casing 10B. The developer is stored in the storage chamber 13B. The casing 10B also has an opening 14B. The opening 14B is located at one end of the casing 10B in the second direction. The external space of the casing 10B and the storage chamber 13B communicate with each other via the opening 14B. The casing 10B may have a handle on the outer surface of the other end in the second direction.

[0103] The agitator 20B has an agitator shaft 21B and blades 22B. The agitator shaft 21B extends along the first direction. The blades 22B extend from the agitator shaft 21B toward the inner surface of the casing 10B. A portion of the agitator shaft 21B and the blades 22B are disposed within the storage chamber 13B of the casing 10B. An agitator gear (not shown) included in the gear unit 50B is attached to the end of the agitator shaft 21B in the first direction. The agitator shaft 21B is fixed so as not to rotate relative to the agitator gear. When the agitator gear rotates, the agitator shaft 21B and the blades 22B rotate about a rotation axis extending in the first direction. The rotation of the blades 22B agitates the developer in the storage chamber 13B.

[0104] The developing roller 30B is a roller that can rotate about a rotation axis A1 that extends in the first direction. The developing roller 30B is located in an opening 14B of the casing 10B. In other words, the developing roller 30B is located at one end of the casing 10B in the second direction. The developing roller 30B has a developing roller main body 31B and a developing roller shaft 32B. The developing roller main body 31B is a cylindrical member that extends in the first direction. The developing roller main body 31B is made of, for example, elastic rubber. The developing roller shaft 32B is a cylindrical member that penetrates the developing roller main body 31B and extends in the first direction. The developing roller shaft 32B is conductive. The developing roller shaft 32B is made of a metal or a conductive resin.

[0105] The developing roller main body 31B is fixed to the developing roller shaft 32B so as not to rotate relative to it. A developing roller gear 51B included in the gear unit 50B is attached to the end of the developing roller shaft 32B in the first direction. The developing roller shaft 32B is fixed to the developing roller gear 51B so as not to rotate relative to it. Therefore, when the developing roller gear 51B rotates, the developing roller shaft 32B also rotates, and the developing roller main body 31B rotates together with the developing roller shaft 32B.

[0106] The developing roller shaft 32B does not have to penetrate the developing roller main body 31B in the first direction. For example, the developing roller shaft 32B may extend in the first direction from both ends of the developing roller main body 31B in the first direction.

[0107] The developing cartridge 1 also has a supply roller (not shown). The supply roller is a roller that can rotate about a rotation axis that extends in the first direction. The supply roller is located between the agitator 20B and the developing roller 30B. The supply roller has a supply roller main body and a supply roller shaft. The supply roller main body is a cylindrical member that extends in the first direction. The supply roller main body is made of, for example, elastic rubber. The supply roller shaft is a cylindrical member that penetrates the supply roller main body and extends in the first direction.

[0108] The supply roller body is fixed to the supply roller shaft so as not to rotate relative to it. A supply roller gear (not shown) included in gear unit 50 is attached to the end of the supply roller shaft in the first direction. The supply roller shaft is fixed to the supply roller gear so as not to rotate relative to it. Therefore, when the supply roller gear rotates, the supply roller shaft also rotates, and the supply roller body rotates together with the supply roller shaft.

[0109] The supply roller shaft does not have to penetrate the supply roller main body in the first direction. For example, the supply roller shaft may extend in the first direction from both ends of the supply roller main body in the first direction.

[0110] When the developer cartridge 1B receives a driving force, developer is supplied from the storage chamber 13B in the casing 10B via the supply roller to the outer circumferential surface of the developer roller 30B. At this time, the developer is frictionally charged between the supply roller and the developer roller 30B. Meanwhile, a bias voltage is applied to the developer roller shaft 32B of the developer roller 30B. Therefore, the developer is attracted to the outer circumferential surface of the developer roller main body 31B by the electrostatic force between the developer roller shaft 32B and the developer.

[0111] The developing cartridge 1B also has a layer thickness regulating blade (not shown). The layer thickness regulating blade shapes the developer supplied to the outer peripheral surface of the developing roller main body 31B to a uniform thickness. The developer on the outer peripheral surface of the developing roller main body 31B is then supplied to a photosensitive drum 92B (described later) of the drum cartridge 2B. At this time, the developer moves from the developing roller main body 31B to the photosensitive drum 92B in accordance with the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 92B. This makes the electrostatic latent image visible on the outer peripheral surface of the photosensitive drum 92B.

[0112] The gear portion 50B is located on the second outer surface 12B of the casing 10B. As shown in FIG. 5, the gear portion 50B includes the above-described agitator gear, developing roller gear 51B, and supply roller gear, as well as multiple idle gears, a coupling 52B, and a gear cover 53B. The gear cover 53B, together with the casing 10B, constitutes the housing of the developer cartridge 1B. The gear cover 53B is fixed to the second outer surface 12B of the casing 10B, for example, by screws. At least some of the multiple gears are located between the second outer surface 12B and the gear cover 53B.

[0113] The gear cover 53B has a cylindrical collar 531B that protrudes in the first direction. The coupling 52B is housed inside the collar 531B. The coupling 52B has an engaging portion 521B that is recessed in the first direction. The engaging portion 521B is exposed from the gear cover 53B. When the developer cartridge 1B attached to the drum cartridge 2B is attached to the image forming apparatus, the drive shaft of the image forming apparatus connects with the engaging portion 521B of the coupling 52B. Then, rotation of the drive shaft is transmitted to the agitator gear, multiple idle gears, the developing roller gear 51B, and the supply roller gear via the coupling 52B.

[0114] The gears included in the gear section 50B may transmit a rotational force by meshing of teeth, or may transmit a rotational force by friction.

[0115] The first bearing 60B is located on the first outer surface 11B of the casing 10B. The first bearing 60B rotatably supports one end of the developing roller shaft 32B in the first direction. As shown in FIGS. 15 and 16 , the first bearing 60B has a first end 61B and a second end 62B. The second end 62B is farther away from the developing roller shaft 32B than the first end 61B. The second end 62B is farther away in the second direction from one end of the casing 10B in the second direction than the first end 61B. The first bearing 60B extends along the first outer surface 11B of the casing 10B between the first end 61B and the second end 62B.

[0116] The first bearing 60B has a first arm 63B and a second arm 64B. The second arm 64B is farther away from the developing roller shaft 32B than the first arm 63B. The second arm 64B is farther away in the second direction from one end of the casing 10B in the second direction than the first arm 63B. The first arm 63B has the first end 61B described above. The second arm 64B has the second end 62B described above. The first arm 63B extends, for example, linearly along the first outer surface 11B of the casing 10B. The second arm 64B extends, for example, linearly along the first outer surface 11B of the casing 10B. However, the first arm 63B is bent with respect to the second arm 64B. The angle formed between the first arm 63B and the second arm 64B is an obtuse angle.

[0117] In this embodiment, the first arm 63B and the second arm 64B are integrally formed. However, the first arm 63B and the second arm 64B may be separate parts. In that case, it is sufficient that the first arm 63B and the second arm 64B are fixed to each other.

[0118] The first bearing 60B has a first insertion hole 65B. The first insertion hole 65B extends in the first direction at a first end 61B of the first bearing 60B. The first insertion hole 65B may be a through-hole that penetrates the first end 61B in the first direction, or it may not penetrate the first end 61B. One end of the developing roller shaft 32B in the first direction is inserted into the first insertion hole 65B. This allows the first bearing 60B to be attached to one end of the developing roller shaft 32B in the first direction. The one end of the developing roller shaft 32B in the first direction is rotatably supported about the rotation axis A1 that extends in the first direction. The first bearing 60B is also rotatable about the developing roller shaft 32B with respect to the casing 10B. Specifically, the second end 62B is rotatable about the rotation axis A1 with respect to the first end 61B.

[0119] The first bearing 60B is a conductive development electrode. The first bearing 60B is made of, for example, a conductive resin. However, the first bearing 60B may also be made of metal. A first end 61B of the first bearing 60B contacts one end of the development roller shaft 32B in the first direction. Therefore, the first end 61B of the first bearing 60B is electrically connected to the development roller shaft 32B.

[0120] The first bearing 60B also has a first hole 67B. The first hole 67B is located between the first end 61B and the second end 62B. The first hole 67B also penetrates the first bearing 60B in the rotation direction about the rotation axis A1. That is, the first hole 67B extends in a third direction that intersects with the first and second directions. However, the first hole 67B does not have to penetrate the first bearing 60B. The other end 112B of the first lever 110B, which will be described later, is inserted into the first hole 67B.

[0121] The first lever 110B is located on the first outer surface 11B of the casing 10B. As shown in FIG. 16, the first lever 110B has one end 111B, another end 112B, and a cam surface 113B. The one end 111B is located at one end of the first lever 110B in a third direction intersecting the first and second directions. The other end 112B is located at the other end of the first lever 110B in the third direction. In other words, the other end 112B is spaced from the one end 111B to the other side in the third direction. The cam surface 113B is located between the one end 111B and the other end 112B in the third direction. In addition, the one end 111B of the first lever 110B has a first protrusion 114B. The first protrusion 114B protrudes in the first direction from the one end 111B of the first lever 110B. The other end 112B of the first lever 110B has a second protrusion 115B. The second protrusion 115B protrudes in the first direction from the other end 112B of the first lever 110B.

[0122] The first lever 110B is movable relative to the casing 10B. When the developer cartridge 1B is attached to the drum cartridge 2B, the cam surface 113B can come into contact with a drum frame 91B (described later) of the drum cartridge 2B. The first lever 110B is rotatable about the cam surface 113B between a first position and a second position.

[0123] The holder 120B is located on the first outer surface 11B of the casing 10B. The holder 120B is fixed to the first outer surface 11B of the casing 10B, for example, by screws. A portion of the first lever 110B is located between the first outer surface 11B and the holder 120B. The first protrusion 114B of the first lever 110B is located on one side of the holder 120B in the third direction. The second protrusion 115B of the first lever 110B is located on the other side of the holder 120B in the third direction. The first protrusion 114B and the holder 120B face each other in the third direction. This prevents the first lever 110B from slipping out of the holder 120B from one side to the other in the third direction. In other words, the holder 120B holds the first lever 110B movably relative to the casing 10B.

[0124] FIG. 19 is a diagram showing a cross section of the first bearing 60B and a side view of the first lever 110B. As indicated by the dashed arrow in FIG. 19, the other end 112B of the first lever 110B is inserted into the first hole 67B of the first bearing 60B. The first bearing 60B also has a lever receiving portion 68B. The lever receiving portion 68B is located inside the first hole 67B. The lever receiving portion 68B has a U-shape that opens toward the other side in the third direction. The second protrusion 115B of the first lever 110B is inserted into the lever receiving portion 68B. This engages the other end 112B of the first lever 110B with the first bearing 60B. The first lever 110B is also prevented from slipping out of the first bearing 60B toward one side in the third direction.

[0125] As shown in FIG. 19, the first bearing 60B has an arc-shaped wall portion 651B on the periphery of the first insertion hole 65B. The wall portion 651B protrudes toward one side in the second direction from a portion of the periphery of the first insertion hole 65B on the other side in the second direction. On the other hand, as shown in FIG. 16, the developing roller shaft 32B has an annular engagement groove 321B on its outer circumferential surface. The engagement groove 321B is located on one side in the first direction relative to the first outer surface 11B of the casing 10B. The wall portion 651B protrudes toward the engagement groove 321B.

[0126] 20 and 21 are diagrams showing how the first bearing 60B, the first lever 110B, and the holder 120B are attached to the developing cartridge 1B.

[0127] When attaching the first bearing 60B, the first lever 110B, and the holder 120B to the developer cartridge 1B, first, the second protrusion 115B of the first lever 110B is inserted into the lever receiving portion 68B of the first bearing 60B. This causes the other end 112B of the first lever 110B to engage with the first bearing 60B. Next, as shown in FIG. 20, the developing roller shaft 32B is inserted into the first insertion hole 65B of the first bearing 60B. Next, the first bearing 60B and the first lever 110B are rotated to one side in the third direction about the rotation axis A1. Thereafter, as shown in FIG. 21, the holder 120B is fixed to the first outer surface 11B of the casing 10B. This causes the first lever 110B to be held by the holder 120B.

[0128] In this way, when the first lever 110B engaged with the first bearing 60B is held by the holder 120, the wall portion 651B of the first bearing 60B is inserted into the engagement groove 321B of the developing roller shaft 32B. This prevents the first bearing 60B from slipping off from the developing roller shaft 32B to one side in the first direction.

[0129] When the first bearing 60B rotates from one side to the other side in the third direction about the rotation axis A1, the first lever 110B moves from one side to the other side in the third direction together with the lever receiving portion 68B of the first bearing 60B. However, the first convex portion 114B of the first lever 110B comes into contact with the holder 120B, thereby stopping the movement of the first lever 110B from one side to the other side in the third direction. Furthermore, when the movement of the first lever 110B stops, the lever receiving portion 68B of the first bearing 60B comes into contact with the second convex portion 115B of the other end 112B of the first lever 110B, thereby stopping the rotation of the first bearing 60B from one side to the other side in the third direction. As a result, the rotation range of the first bearing 60B to the other side in the third direction is limited.

[0130] As described above, in the developing cartridge 1B of this embodiment, the holder 120B prevents the first lever 110B from slipping out from one side to the other in the third direction. The first lever 110B also stops the first bearing 60B from rotating from one side to the other in the third direction. Therefore, there is no need to provide a component separate from the first lever 110B and the holder 120B for stopping the first bearing 60B from rotating from one side to the other in the third direction. This reduces the number of components in the developing cartridge 1B.

[0131] 16 and 20, the casing 10B has a casing protrusion 15B. The casing protrusion 15B extends from the first outer surface 11B of the casing 10B toward one side in the first direction. Meanwhile, as shown by the dashed line in FIGS. 20 and 21, the first bearing 60B has an electrode protrusion 601B. The electrode protrusion 601B extends in the first direction from the first bearing 60B toward the first outer surface 11B of the casing 10B.

[0132] When the first bearing 60B rotates from the other side to the one side in the third direction about the rotation axis A1, the electrode protrusion 601B comes into contact with the casing protrusion 15B. This stops the rotation of the first bearing 60B from the other side to the one side in the third direction. In this way, in the developer cartridge 1B of this embodiment, the casing protrusion 15B of the casing 10B stops the rotation of the first bearing 60B from the other side to the one side in the third direction. Therefore, there is no need to provide a component separate from the casing 10B for stopping the rotation of the first bearing 60B from the other side to the one side in the third direction. This eliminates the need to provide a component for stopping the rotation of the first bearing 60B from the other side to the one side in the third direction. This reduces the number of components in the developer cartridge 1B.

[0133] The second bearing 70B is located on the second outer surface 12B of the casing 10B. More specifically, the second bearing 70B is located on the outer surface of the gear cover 53B. The first bearing 60B and the second bearing 70B are positioned to overlap in the first direction. The second bearing 70B rotatably supports the other end of the developing roller shaft 32B in the first direction. As shown in FIGS. 17 and 18, the second bearing 70B has a third end 71B and a fourth end 72B. The fourth end 72B is farther from the developing roller shaft 32B than the third end 71B. Furthermore, the fourth end 72B is farther from one end of the casing 10B in the second direction than the third end 71B. The second bearing 70B extends along the second outer surface 12B of the casing 10B between the third end 71B and the fourth end 72B.

[0134] The second bearing 70B has a third arm 73B and a fourth arm 74B. The fourth arm 74B is farther away from the developing roller shaft 32B than the third arm 73B. The fourth arm 74B is also farther away in the second direction from one end of the casing 10B in the second direction than the third arm 73B. The third arm 73B has the third end 71B described above. The fourth arm 74B has the fourth end 72B described above. The third arm 73B extends, for example, linearly along the second outer surface 12B of the casing 10B. The fourth arm 74B extends, for example, linearly along the second outer surface 12B of the casing 10B. However, the third arm 73B is bent with respect to the fourth arm 74B. The angle formed between the third arm 73B and the fourth arm 74B is an obtuse angle.

[0135] In this embodiment, the third arm 73B and the fourth arm 74B are integrally formed. However, the third arm 73B and the fourth arm 74B may be separate parts. In that case, it is sufficient that the third arm 73B and the fourth arm 74B are fixed to each other.

[0136] FIG. 22 is a partial cross-sectional view of the developing cartridge 1B near the second bearing 70B. As shown in FIGS. 17, 18, and 22, the second bearing 70B has a second insertion hole 75B. The second insertion hole 75B extends in the first direction at the third end 71B of the second bearing 70B. The second insertion hole 75B may be a through-hole that penetrates the third end 71B in the first direction, or it may not penetrate the third end 71B. The second insertion hole 75B has a cylindrical inner circumferential surface. The other end of the developing roller shaft 32B in the first direction is inserted into the second insertion hole 75B. The other end of the developing roller shaft 32B in the first direction is rotatably supported about the rotation axis A1 extending in the first direction. The second bearing 70B is also rotatable about the developing roller shaft 32B with respect to the casing 10B. Specifically, the fourth end 72B is rotatable about a rotation axis A1 relative to the third end 71B.

[0137] The second bearing 70B also has a second hole 78B. The second hole 78B extends in the first direction between the third end 71B and the fourth end 72B. The second hole 78B also penetrates the second bearing 70B in the first direction. However, the second hole 78B does not have to penetrate the second bearing 70B.

[0138] 22, the second bearing 70B has a claw receiving portion 781B. The claw receiving portion 781B is located inside the second hole 78B. Meanwhile, the casing 10B has two claw portions 16B. The claw portions 16B extend from the second outer surface 12B of the casing 10B toward the other side in the first direction. In this embodiment, the two claw portions 16B extend from the outer surface of the gear cover 53B, which functions as part of the casing.

[0139] The tip 161B of the claw portion 16B is located inside the second hole 78B. The tip 161B of the claw portion 16B protrudes in a direction intersecting the first direction and engages with the surface of the claw receiving portion 781B on the other side in the first direction. This holds the second bearing 70B against the gear cover 53B. Also, the second bearing 70B is prevented from slipping out to the other side in the first direction. In this way, there is no need to provide an engagement groove to prevent the second bearing 70B from slipping out at the portion of the developing roller shaft 32B that is inserted into the second insertion hole 75B.

[0140] When the second bearing 70B rotates from one side to the other side in the third direction about the rotation axis A1, a portion of the second bearing 70B on the one side in the third direction of the second hole 78B comes into contact with the claw portion 16B. This stops the rotation of the second bearing 70B from one side to the other side in the third direction. Furthermore, when the second bearing 70B rotates from the other side to one side in the third direction about the rotation axis A1, a portion of the second bearing 70B on the other side in the third direction of the second hole 78B comes into contact with the claw portion 16B. This stops the rotation of the second bearing 70B from the other side to one side in the third direction.

[0141] In this way, in the developer cartridge 1B of this embodiment, the claw portion 16B stops the rotation of the second bearing 70B. Therefore, there is no need to provide a component for stopping the rotation of the second bearing 70B separately from the claw portion 16B. This allows the number of components of the developer cartridge 1B to be reduced.

[0142] 17 and 18, the second bearing 70B has a pressed protrusion 701B. The pressed protrusion 701B protrudes from the other surface of the second bearing 70B in the first direction toward the other side in the first direction. That is, the pressed protrusion 701B protrudes in a direction away from the casing 10B. The pressed protrusion 701B can come into contact with a separating lever 97B (described later) of the drum cartridge 2B when a separating operation (described later) is performed.

[0143] <2-3. Structure of drum cartridge> As shown in Figures 12 to 14, the drum cartridge 2B includes a drum frame 91B and a photosensitive drum 92B. The developer cartridge 1B is attached to the drum frame 91B. The photosensitive drum 92B is a cylindrical drum that is rotatable about a rotation axis that extends in the first direction. The outer peripheral surface of the photosensitive drum 92B is covered with a photosensitive material. The photosensitive drum 92B is located at one end of the drum frame 91B in the second direction. When the developer cartridge 1B is attached to the drum frame 91B, the outer peripheral surface of the developer roller 30B comes into contact with the outer peripheral surface of the photosensitive drum 92B.

[0144] 23 and 24 are views of the developer cartridge 1B being attached to the drum cartridge 2B, viewed from one side in the first direction. FIG. 25 is a view of the developer cartridge 1B and drum cartridge 2B after attachment, viewed from one side in the first direction. FIG. 26 is a view of the developer cartridge 1B and drum cartridge 2B during a separating operation, which will be described later, viewed from one side in the first direction. FIG. 27 is a view of the developer cartridge 1B and drum cartridge 2B after attachment, viewed from the other side in the first direction. FIG. 28 is a view of the developer cartridge 1B and drum cartridge 2B during a separating operation, which will be described later, viewed from the other side in the first direction.

[0145] 23 to 25, the drum cartridge 2B has a first guide surface 93B and a second guide surface 94B. The first guide surface 93B and the second guide surface 94B are located at one end of the drum frame 91B in the first direction. The first guide surface 93B and the second guide surface 94B are spaced apart in the rotation direction around the rotation axis of the photosensitive drum 92B.

[0146] As shown in FIGS. 23 to 26, the drum cartridge 2B includes a first pressing member 95B and a first coil spring 96B. The first pressing member 95B and the first coil spring 96B are conductive. The first pressing member 95B is made of, for example, conductive resin. The first coil spring 96B is made of, for example, metal. The first pressing member 95B and the first coil spring 96B are located at one end of the drum frame 91B in the first direction. The first coil spring 96B is an elastic member that can expand and contract in the second direction. One end of the first coil spring 96B in the second direction is connected to the first pressing member 95B. The other end of the first coil spring 96B in the second direction is connected to the drum frame 91B. When the developer cartridge 1B is attached to the drum cartridge 2B, the first pressing member 95B presses the second end 62B of the first bearing 60B toward the photosensitive drum 92B by the elastic force of the first coil spring 96B.

[0147] 27 and 28, the drum cartridge 2B has a third guide surface 931B and a fourth guide surface 941B. The third guide surface 931B and the fourth guide surface 941B are located at the other end of the drum frame 91B in the first direction. The third guide surface 931B and the fourth guide surface 941B are spaced apart in the rotation direction around the rotation axis of the photosensitive drum 92B.

[0148] As shown in FIGS. 27 and 28, the drum cartridge 2B includes a second pressing member 951B and a second coil spring 961B. The second pressing member 951B and the second coil spring 961B are located at the other end of the drum frame 91B in the first direction. The second coil spring 961B is an elastic member that can expand and contract in the second direction. One end of the second coil spring 961B in the second direction is connected to the second pressing member 951B. The other end of the second coil spring 961B in the second direction is connected to the drum frame 91B. When the developer cartridge 1B is attached to the drum cartridge 2B, the second pressing member 951B presses the fourth end 72B of the second bearing 70B toward the photosensitive drum 92B by the elastic force of the second coil spring 961B.

[0149] The drum cartridge 2B may include other types of elastic members instead of the first coil spring 96B and the second coil spring 961B. For example, the drum cartridge 2B may include, as elastic members, springs other than coil springs, such as torsion springs or leaf springs, or rubber.

[0150] As shown in Figures 27 and 28, the drum cartridge 2B also includes a separation lever 97B. The separation lever 97B is located at the other end of the drum frame 91B in the first direction. The separation lever 97B is rotatable about a rotation axis extending in the first direction. The separation lever 97B also has a first lever arm 971B and a second lever arm 972B. When the developer cartridge 1B is attached to the drum cartridge 2B, the second lever arm 972B faces the pressed protrusion 701B of the second bearing 70 in the second direction.

[0151] <2-4. Installing the developing cartridge> When the developer cartridge 1B is attached to the drum cartridge 2B, as shown in Figures 23 to 25, the developer cartridge 1B moves relative to the drum cartridge 2B so that the developer roller 30B approaches the photosensitive drum 92B. At this time, the first bearing 60B rotates about the rotation axis A1 in accordance with the shape of the drum frame 91B. Similarly, the second bearing 70B also rotates about the rotation axis A1 in accordance with the shape of the drum frame 91B.

[0152] In this way, when the developer cartridge 1B is attached to the drum cartridge 2B, the first bearing 60B and the second bearing 70B rotate about the rotation axis A1 of the developer roller 30B. Therefore, the first bearing 60B can be disposed between the photosensitive drum 92B and the first pressing member 95B, and the second bearing 70B can be disposed between the photosensitive drum 92B and the second pressing member 951B, without significantly rotating the casing 10B relative to the drum frame 91B. Therefore, a user of the image forming apparatus can move the developer roller 30B closer to the photosensitive drum 92B without significantly rotating the casing 10B.

[0153] When the first bearing 60B is disposed between the photosensitive drum 92B and the first pressing member 95B, the first pressing member 95B comes into contact with the second end 62B of the first bearing 60B. Then, due to the elastic force of the first coil spring 96B, the first pressing member 95B presses the second end 62B of the first bearing 60B toward the photosensitive drum 92B. As a result, as shown in FIG. 25 , the first end 61B of the first bearing 60B comes into contact with the first guide surface 93B, and the other portion of the first bearing 60B comes into contact with the second guide surface 94B. This fixes the position of the first bearing 60B relative to the drum frame 91B.

[0154] Similarly, the second pressing member 951B presses the fourth end 72B of the second bearing 70B toward the photosensitive drum 92B. As a result, as shown in Fig. 27, the third end 71B of the second bearing 70B contacts the third guide surface 931B, and the other portion of the second bearing 70B contacts the fourth guide surface 941B. This fixes the position of the second bearing 70B relative to the drum frame 91B.

[0155] Furthermore, with the positions of the first bearing 60B and the second bearing 70B fixed relative to the drum frame 91, the first pressing member 95B presses the first bearing 60B, and the second pressing member 951B presses the second bearing 70B. As a result, the outer peripheral surface of the developing roller 30B comes into contact with the outer peripheral surface of the photosensitive drum 92B. The developing roller 30B is then pressed against the photosensitive drum 92B.

[0156] As described above, in this embodiment, the first bearing 60B has a first end 61B and a second end 62B, and the second end 62B is rotatable relative to the first end 61B. Furthermore, the second bearing 70B has a third end 71B and a fourth end 72B, and the fourth end 72B is rotatable relative to the third end 71B. Therefore, the first end 61B and the second end 62B of the first bearing 60B and the third end 71B and the fourth end 72B of the second bearing 70B can be used to position the developing roller 30B relative to the photosensitive drum 92B.

[0157] In this embodiment, when the developer cartridge 1B is attached to the drum cartridge 2B, the first bearing 60B and the second bearing 70B rotate about the rotation axis A1. Similarly, when the developer cartridge 1B is removed from the drum cartridge 2B, the first bearing 60B and the second bearing 70B rotate about the rotation axis A1. Therefore, the developer cartridge 1B can be smoothly attached to and removed from the drum cartridge 2B by rotating the first bearing 60B and the second bearing 70B without rotating the casing 10B.

[0158] <2-5. Voltage supply> The first pressing member 95B and the first coil spring 96B are conductive. The first pressing member 95B is made of, for example, a conductive resin. The first coil spring 96B is made of, for example, a metal. The drum cartridge 2B also includes an electrode terminal 98B that is in electrical contact with the first coil spring 96B. As shown in FIGS. 12 and 13, the electrode terminal 98B is exposed on the outer surface of the drum frame 91B. As described above, the developing roller shaft 32B and the first bearing 60B are also conductive. Therefore, when the developing cartridge 1B is installed in the drum cartridge 2B and the first pressing member 95B contacts the first bearing 60B, the electrode terminal 98B, the first coil spring 96B, the first pressing member 95B, the first bearing 60B, and the developing roller shaft 32B are electrically connected to one another.

[0159] When the developer cartridge 1B, which is attached to the drum cartridge 2B, is installed in an image forming apparatus, the electrode terminal of the image forming apparatus comes into contact with the electrode terminal 98B of the drum cartridge 2B. Then, a bias voltage is supplied from the image forming apparatus to the developer roller shaft 32B via the electrode terminal 98B, the first coil spring 96B, the first pressing member 95B, and the first bearing 60B. As a result, the developer is attracted to the outer peripheral surface of the developer roller body 31B by electrostatic force generated by the bias voltage.

[0160] In this manner, in this embodiment, the bias voltage is supplied to the first bearing 60B of the developer cartridge 1B via the first pressing member 95B of the drum cartridge 2B. This reduces the number of parts in the drum cartridge 2B compared to when a conductive part for supplying voltage to the first bearing 60B is provided separately from the first pressing member 95B. This allows the drum cartridge 2B to be made smaller.

[0161] Furthermore, the first bearing 60B of this embodiment fulfills multiple functions: (1) a function as a bearing that rotatably supports the developing roller shaft 32B, (2) a function as a positioning member that positions the developing roller 30B with respect to the photosensitive drum 92B when the developing cartridge 1B is attached to the drum cartridge 2B, and (3) a function as a developing electrode that supplies a bias voltage to the developing roller shaft 32B. Therefore, compared to when these functions are realized by separate members, the number of parts of the developing cartridge 1B can be reduced and the developing cartridge 1B can be made smaller.

[0162] <2-6. About the separation operation> After the developer cartridge 1B is installed in the image forming apparatus while attached to the drum cartridge 2B, it can perform a separation operation by a driving force supplied from the image forming apparatus. The separation operation is an operation for temporarily separating the developer roller 30B from the photosensitive drum 92B. For example, when performing monochrome printing in the image forming apparatus, the developer cartridges 1B of each color other than black perform the separation operation. However, there may be cases where only the black developer cartridge 1B performs the separation operation.

[0163] As shown in Figures 25 and 27, when the developer cartridge 1B is attached to the drum cartridge 2B, the developer cartridge 1B is positioned at a contact position where the developer roller 30B contacts the photosensitive drum 92B. The first lever 110B is positioned at the first position. In the first position, the second protrusion 115B of the first lever 110B is separated from the inner surface of the lever receiving portion 68B of the first bearing 60B. Therefore, the second protrusion 115B of the first lever 110B does not press the inner surface of the lever receiving portion 68B. The cam surface 113B of the first lever 110B is in contact with the drum frame 91B. The separation lever 97B is positioned at the third position. In the third position, the second lever arm 972B of the separation lever 97B is separated from the pressed protrusion 701B of the second bearing 70B. Therefore, the second lever arm 972B of the separating lever 97B does not press the pressed projection 701B of the second bearing 70B.

[0164] When performing the separation operation, the image forming apparatus applies a driving force to one end 111B of the first lever 110B. Specifically, the image forming apparatus operates a drive lever (not shown). This causes the drive lever to press the one end 111B of the first lever 110B, as indicated by the dashed arrow in FIG. 26 . This causes the first lever 110B to rotate from the first position to the second position around the cam surface 113B. At this time, the other end 112B of the first lever 110B moves in a direction away from the photosensitive drum 92B and presses the inner surface of the lever receiving portion 68B of the first bearing 60B. Specifically, the other end 112B of the first lever 110B presses the second end 62B of the first bearing 60B in a direction away from the developing roller 30B against the pressing force of the first pressing member 95B. As a result, the first bearing 60B moves together with the other end 112B of the first lever 110B in a direction away from the photosensitive drum 92B.

[0165] Furthermore, when the image forming apparatus performs the separation operation, it applies a driving force to the first lever arm 971B of the separation lever 97B. Specifically, the image forming apparatus operates another drive lever (not shown). This causes the drive lever to press the first lever arm 971B, as indicated by the dashed arrow in FIG. 28. This causes the separation lever 97B to rotate from the third position to the fourth position about the rotation axis extending in the first direction. At this time, the second lever arm 972B of the separation lever 97B moves in a direction away from the photosensitive drum 92B and presses the pressed protrusion 701B of the second bearing 70B. Specifically, the second lever arm 972B presses the fourth end 72B of the second bearing 70B in a direction away from the developing roller 30B against the pressing force of the second pressing member 951B. As a result, the second bearing 70B moves together with the second lever arm 972B in a direction away from the photosensitive drum 92B.

[0166] As a result, the casing 10B and the developing roller 30B move together with the first bearing 60B and the second bearing 70B in a direction away from the photosensitive drum 92B. As a result, the outer peripheral surface of the developing roller 30B moves away from the outer peripheral surface of the photosensitive drum 92B. In other words, the developing cartridge 1B moves from the contact position to the separated position relative to the drum cartridge 2B.

[0167] Thus, in this embodiment, in response to the force that one end 111B of the first lever 110B receives from the drive lever of the image forming apparatus, the other end 112B of the first lever 110B presses the inner surface of the lever receiving portion 68B of the first bearing 60B. This allows for the application of force to move the developer cartridge 1B from the contact position to the separation position. In other words, the driving force supplied from the image forming apparatus can be transmitted to the first bearing 60B by the first lever 110B, which has one end 111B functioning as a force point, the other end 112B functioning as a point of application, and the cam surface 113B functioning as a fulcrum.

[0168] In other words, the driving force supplied from the image forming apparatus is transmitted to the first bearing 60B of the developer cartridge 1B without passing through the drum cartridge 2B. In this way, there is no need to provide a component for relaying the driving force at one end of the drum cartridge 2B in the first direction. This reduces the number of components in the drum cartridge 2B. This also allows the drum cartridge 2B to be made more compact.

[0169] Furthermore, in this developing cartridge 1B, one end 111B of the first lever 110B has a first protrusion 114B that protrudes in a first direction. Therefore, the surface area of ​​the one end 111B of the first lever 110B is larger than when the first protrusion 114B is not present. Therefore, during the separation operation, the drive lever of the image forming device can stably press the one end 111B of the first lever 110B. This stabilizes the separation operation of the image forming device.

[0170] Furthermore, in this developer cartridge 1B, the first bearing 60B and the second bearing 70B that support the developing roller shaft 32B receive a pressing force during the separating operation. This allows the number of parts in the developer cartridge 1B to be reduced compared to when a separate member is provided to receive the pressing force during the separating operation, separate from the first bearing 60B and the second bearing 70B. This allows the developer cartridge 1B to be made smaller.

[0171] Furthermore, the first bearing 60B is rotatable about the rotation axis A1, so that the first lever 110B can press the inner surface of the lever receiving portion 68B of the first bearing 60B in the optimum direction.

[0172] Furthermore, when the developer cartridge 1B moves from the contact position to the separated position, the first bearing 60B moves along the second guide surface 94B. This allows the first lever 110B to press the first bearing 60B while maintaining the position of the first bearing 60B centered on the rotation axis A1. Furthermore, when the developer cartridge 1B moves from the contact position to the separated position, the second bearing 70B moves along the fourth guide surface 941B. This allows the separation lever 97B to press the second bearing 70B while maintaining the position of the second bearing 70B centered on the rotation axis A1.

[0173] <3. Modifications> Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment. Various modifications will be described below, focusing on differences from the above embodiment.

[0174] In the above embodiment, the developer cartridge 1 includes a first bearing and a second bearing. Both the first bearing and the second bearing are rotatable relative to the casing 10. However, the second bearing may not be rotatable relative to the casing 10. The developer cartridge 1 may not include a second bearing. In that case, it is sufficient that the first bearing is disposed at either end of the casing 10 in the first direction.

[0175] In the above embodiment, the developer cartridge 1 is attached to a drum cartridge 2 having one photosensitive drum 92. However, the developer cartridge 1 may be attached to a drum cartridge having a plurality of photosensitive drums 92.

[0176] Furthermore, the detailed shape of the developing cartridge 1 may differ from the shape shown in each drawing of the present application. Furthermore, the elements appearing in the above-described embodiments and modifications may be combined as appropriate within the scope of not causing any contradiction. [Explanation of symbols]

[0177] 1,1B developing cartridge 2,2B drum cartridge 10,10B casing 15B Casing protrusion 16B Claw part 20,20B Agitator 30,30B Developing roller 40 Supply roller 50,50B gear section 60,60B No. 1 bearing 70,70B No. 2 bearing 91,91B drum frame 92,92B Photosensitive drum 110,110B First lever 120,120B holder A1 rotation axis

Claims

1. A developer cartridge, a developing roller having a developing roller shaft extending in a first direction; a casing capable of accommodating a developer, the casing having the developing roller positioned at one end in a second direction intersecting the first direction; a developer electrode electrically connected to the developer roller shaft and movable together with the casing and the developer roller; a first lever movable relative to the casing; a holder that movably holds the first lever relative to the casing; Equipped with the holder prevents the first lever from coming out of the holder while holding the first lever; the developing electrode is attached to one end of the developing roller shaft in the first direction, The developing cartridge is a bearing attached to the other end of the developing roller shaft in the first direction, the bearing having a first end having a second insertion hole into which the other end of the developing roller shaft is inserted, and a second end that is farther from the developing roller shaft than the first end, the bearing being movable together with the casing and the developing roller; The developing cartridge further comprises:

2. 2. The developing cartridge according to claim 1, The bearing is a second hole extending in the first direction between the first end and the second end; a claw receiving portion located inside the second hole; and The casing comprises: a claw portion extending in the first direction, the tip of which projects in a direction intersecting the first direction and engages with the claw receiving portion; A developing cartridge comprising:

3. 3. The developing cartridge according to claim 2, the bearing is rotatable about the developing roller shaft; The developing cartridge, wherein the claw portion stops rotation of the bearing by coming into contact with the bearing.

4. 4. The developing cartridge according to claim 1, The developing cartridge is used for a drum cartridge having a photosensitive drum, the drum cartridge has a spacing lever that is rotatable about a shaft that extends in the first direction, The bearing is a pressed protrusion that protrudes in a direction away from the casing and is capable of contacting the separating lever; A developing cartridge comprising:

Images