Developer Box

Abstract

A developer cartridge includes: a housing; a developing roller; a developing electrode; a gear; a rack meshing with the gear, the rack being movable from one end of the housing toward the other end of the housing opposite the first end, the rack including a protrusion; and a cam movable from a first position to a second position, the second position being further from the housing in the axial direction than the first position. The cam includes: a first cam surface contacting the protrusion when the cam is in the first position, and moving the cam from the first position to the second position when the rack moves from the one end of the housing toward the other end of the housing while the first cam surface is in contact with the protrusion; and a second cam surface contacting the developing electrode when the cam moves from the first position to the second position, causing the developing electrode to move in a direction away from the cam, the direction away from the cam being a direction different from the direction of movement of the rack and the direction of movement of the cam.

Description

[0001] This application is a divisional application of the application with application number 201710873925.0, application date September 26, 2017, and invention name “Developer Box”. Technical Field

[0002] The present invention relates to a developing box having a developing roller. Background Art

[0003] A developer cartridge previously included a detection protrusion for moving an actuator located in the main housing of an image forming apparatus. The detection protrusion includes a gear. The detection protrusion is rotatable about an axis. The actuator moves when the detection protrusion pushes the actuator during the rotation of the gear. Furthermore, the gear has a toothless portion. When the toothless portion faces a drive gear that transmits driving force to the gear, the gear disengages from the drive gear. As a result, the gear stops rotating. When the gear stops rotating, the detection protrusion also stops rotating.

[0004] In the above-mentioned developing cartridge, it is desirable to release the meshing between the gears other than the above-mentioned gear and the driving gear. Summary of the Invention

[0005] In view of the above situation, an object of the present invention is to provide a developing box capable of releasing the engagement between a gear other than the above gear and a driving gear.

[0006] In order to achieve the above and other purposes, the present invention provides a developer box, comprising: a shell, which is configured to accommodate colorant in its interior; a developing roller, which is capable of rotating about a first axis extending in an axial direction, and the developing roller is located at one end of the shell; a developing electrode, which is electrically connected to the developing roller; a gear, which is capable of rotating about a second axis parallel to the first axis; a rack, which is engaged with the gear, and the rack is capable of moving in a direction from the one end of the shell toward the other end of the shell opposite to the one end, the rack including a protrusion; and a cam, which is capable of moving from a first position to a second position, the second position being farther from the shell in the axial direction than the first position. , the cam comprises: a first cam surface, which contacts the protrusion when the cam is in the first position, and when the first cam surface is in contact with the protrusion, when the rack moves along the direction from the one end of the shell toward the other end of the shell, the first cam surface causes the cam to move from the first position to the second position; and a second cam surface, which contacts the developing electrode and causes the developing electrode to move in a direction away from the cam when the cam moves from the first position to the second position, and the direction away from the cam is a direction different from the moving direction of the rack and the moving direction of the cam.

[0007] Preferably, the developing box further includes a spring, and the spring is used to electrically connect the developing electrode to the developing roller.

[0008] Preferably, the developing box further includes a bearing for supporting the developing roller, and the spring has: one end in contact with the developing electrode; and the other end opposite to the one end of the spring, the other end of the spring in contact with the bearing.

[0009] Preferably, in a state where the one end of the spring contacts the developing electrode and the other end of the spring contacts the bearing, the length of the spring is smaller than a natural length of the spring.

[0010] Preferably, the bearing is made of conductive resin.

[0011] Preferably, the developing electrode is made of conductive resin.

[0012] Preferably, the first cam surface has: a first edge; and a second edge, which is located farther from the housing than the first edge in the axial direction, and the first cam surface is inclined so that the first edge is located downstream of the second edge in the moving direction of the rack.

[0013] Preferably, the cam has a third cam surface, which is located downstream of the first cam surface in the moving direction of the rack, and when the cam is in the second position, the third cam surface contacts the protrusion. When the third cam surface is in contact with the protrusion, when the rack moves along the direction from one end of the housing toward the other end of the housing, the third cam surface causes the cam to move from the second position to the first position.

[0014] Preferably, the third cam surface has: a third edge; and a fourth edge, which is located farther from the housing than the third edge in the axial direction, and the third cam surface is inclined so that the fourth edge is located downstream of the third edge in the moving direction of the rack.

[0015] Preferably, the first cam surface is located at a position different from that of the third cam surface in the moving direction of the cam.

[0016] Preferably, the developing cartridge further includes: an agitator configured to agitate the toner contained in the housing; and an agitator gear mounted on an end portion of the agitator and rotatable together with the agitator, the agitator gear serving as the gear.

[0017] Preferably, the developing box further includes a connector, and the connector is located on the opposite side of the developing electrode relative to the housing.

[0018] Preferably, the developing gear has a fourth cam surface, the fourth cam surface contacts the second cam surface and extends parallel to the second cam surface.

[0019] Preferably, the rack includes: a main body portion, which is plate-shaped and extends in the moving direction of the rack; and a plurality of gear teeth, which are engaged with the gear, and the plurality of gear teeth and the protrusion protrude from the main body portion and are located at different positions from each other in the moving direction of the rack.

[0020] Preferably, the protrusion is located at a position different from that of the plurality of gear teeth in the axial direction.

[0021] Preferably, the second cam surface has: a fifth edge; and a sixth edge, which is located farther from the housing than the fifth edge in the axial direction, and the second cam surface is inclined to protrude toward the developing electrode along the direction from the sixth edge toward the fifth edge.

[0022] The present invention also provides a developing box, comprising: a shell configured to accommodate colorant in its interior; a developing roller capable of rotating about a first axis extending in an axial direction, the developing roller being located at one end of the shell; a gear capable of rotating about a second axis extending in the axial direction; a developing electrode electrically connected to the developing roller; a rack capable of moving from the one end of the shell toward the other end of the shell opposite to the one end, the rack capable of moving in a direction from the one end of the shell toward the other end of the shell by engaging with the gear according to the rotation of the gear, the rack including a protrusion; a cover covering at least a portion of the rack, the cover having an opening, the developing electrode being exposed to the outside through the opening; and a cam capable of moving from a first position to a second position, the second position being farther from the shell in the axial direction than the first position, the cam having: a first cam surface having a first edge and a second edge, the The second edge is located farther from the housing than the first edge in the axial direction, the first cam surface is inclined so that the first edge is located downstream of the second edge in the moving direction of the protrusion, the first cam surface moves the cam from the first position to the second position by cooperating with the protrusion, and when the cam is in the second position, the first cam surface is located outside the moving trajectory of the protrusion; and a second cam surface, which can move together with the first cam surface, the second cam surface is located farther from the housing than the first cam surface in the axial direction, the second cam surface can move while contacting the developing electrode, the second cam surface has a fifth edge and a sixth edge, the sixth edge is located farther from the housing than the fifth edge in the axial direction, and the second cam surface is inclined so as to protrude toward the opening along the direction from the sixth edge toward the fifth edge.

[0023] Preferably, the developing box further includes a spring, and the spring is used to electrically connect the developing electrode to the developing roller.

[0024] Preferably, the cam also includes a third cam surface, which is located downstream of the first cam surface in the moving direction of the rack, and when the cam is in the second position, the third cam surface is located within the moving trajectory of the protrusion, and the third cam surface has: a third edge; and a fourth edge, which is located farther from the housing than the third edge in the axial direction, and the third cam surface is inclined so that the fourth edge is located downstream of the third edge in the moving direction of the rack.

[0025] The present invention also provides a developing box, comprising: a shell configured to accommodate colorant in its interior; a developing roller capable of rotating about a first axis extending in an axial direction, the developing roller being located at one end of the shell; a gear capable of rotating about a second axis parallel to the first axis; a rack engaged with the gear, the rack capable of moving in a direction from the one end of the shell toward the other end of the shell opposite to the one end; a cam capable of moving from a first position to a second position, the second position being farther from the shell in the axial direction than the first position, the cam having a protrusion; a spring for activating the cam from the first position to the second position The second position applies force; a cover having an opening; and a developing electrode electrically connected to the developing roller, the developing electrode being capable of moving together with the cam, the developing electrode having a second cam surface, the second cam surface having a fifth edge and a sixth edge, the sixth edge being located farther from the housing in the axial direction than the fifth edge, the second cam surface being inclined to protrude toward the opening in a direction from the sixth edge toward the fifth edge, the rack having: a first retaining surface for contacting the protrusion to hold the cam in the first position; and a second retaining surface for contacting the protrusion to hold the cam in the second position.

[0026] Preferably, the developing electrode and the spring are formed integrally. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The features, advantages and other objects of the present invention will become clear from the following description in conjunction with the accompanying drawings, in which:

[0028] Figure 1 is a perspective view of the developing cartridge according to the first embodiment as viewed from one end side in the axial direction;

[0029] Figure 2 is a perspective view of the developing cartridge according to the first embodiment as viewed from the other end side in the axial direction;

[0030] Figure 3 is an exploded perspective view of components at the other end of the developing cartridge according to the first embodiment;

[0031] Figure 4 is a perspective view of the rack of the developing cartridge according to the first embodiment as viewed from the rack portion side;

[0032] Figure 5 is an exploded perspective view of a gear cover and components accommodated therein of a developing cartridge according to a first embodiment;

[0033] Figure 6 is a perspective view of a cam of a developing cartridge according to a first embodiment;

[0034] Figure 7 is a perspective view showing the structure of the other end side of the developing cartridge according to the first embodiment, with the gear cover omitted;

[0035] Figures 8A to 8D is a cross-sectional view of a fitting portion between the rack and the cam taken along a plane perpendicular to the up-down direction according to the first embodiment, illustrating movement of the rack and the cam;

[0036] Figure 9A and 9B is a cross-sectional view of the rack, cam, and developing electrode taken along a plane perpendicular to a direction from one end to the other end of a housing of a developing cartridge according to the first embodiment, illustrating movement of the rack, cam, and developing electrode;

[0037] Figure 10 is a perspective view showing the structure of the other end side of the developing cartridge according to the second embodiment, with the gear cover omitted;

[0038] Figure 11A and 11B is a perspective view of each component of the developing cartridge according to the second embodiment, wherein Figure 11A This is an exploded perspective view of the gear cover and the components contained therein. Figure 11B This is a three-dimensional diagram of the rack as viewed from the rack side;

[0039] Figures 12A to 12C is a cross-sectional view of a fitting portion between a rack and a cam taken along a plane perpendicular to the up-down direction according to a second embodiment, illustrating movement of the rack and the cam; and

[0040] Figure 13A and 13B It is a cross-sectional view of the rack, cam, and spring electrode taken along a plane perpendicular to a direction from one end to the other end of a casing of a developing cartridge according to the second embodiment, illustrating the movement of the rack, cam, and spring electrode. DETAILED DESCRIPTION

[0041] <First embodiment>

[0042] The following references Figures 1 to 9B A developing cartridge according to a first embodiment will be described, wherein like components are denoted by the same reference numerals to avoid redundant description.

[0043] like Figure 1 As shown, the developing box 1 mainly includes a housing 11, a developing roller 12, a supply roller 15 (see Figure 3 ), an agitator 14 and a coupling 13. The housing 11 accommodates toner therein. In the following description, the axial direction of the developing roller 12 is also simply referred to as the "axial direction".

[0044] The developing roller 12 is a roller that supplies toner to an electrostatic latent image formed on a photosensitive member (not shown). The developing roller 12 is rotatable about a first axis X1 extending in the axial direction. The developing roller 12 has an axially extending shaft 12A. The developing roller 12 is located at one end E10 of the housing 11, in a direction from the shaft 12A toward a shaft 14A of the agitator 14, described later.

[0045] The supply roller 15 is a roller that supplies toner to the developing roller 12. The agitator 14 is a member that stirs the toner in the housing 11.

[0046] The coupling 13 is a member that receives driving force from the outside. Specifically, a retractable input member (not shown) is provided in the main body housing (not shown) of the image forming apparatus (not shown). When the input member advances and enters the coupling 13, thereby engaging the coupling 13 in the rotational direction, driving force is input from the input member to the coupling 13. The driving force input to the coupling 13 is transmitted to the developing roller 12, the supply roller 15, and the agitator 14 via a gear mechanism (not shown).

[0047] The coupling 13 is located at one end of the housing 11 in the axial direction. In other words, the coupling 13 is connected to the developing electrode 20 (described later, see Figure 2 ) are opposite to each other across the housing 11. That is, the coupler 13 is located on a side wall of the housing 11 opposite to the side wall 11A where the developing electrode 20 is located.

[0048] like Figure 2 As shown, the developing box 1 also includes a developing electrode 20, which is located at the other end of the shell 11 in the axial direction. The developing electrode 20 is used to move the actuator AC located in the main body shell of the image forming device. The actuator AC is supported in the main body shell in a rotatable manner. The actuator AC is composed of a conductive member. The image forming device includes a power supply unit (not shown) and an optical sensor (not shown). The power supply unit and the optical sensor are located in the main body shell of the image forming device. The power supply unit provides power to the actuator AC. The optical sensor detects the rotation of the actuator AC.

[0049] When the driving force input to the coupling 13 passes through the gear mechanism and the agitator 14 (see Figure 1 ) is transmitted to the development electrode 20, the development electrode 20 moves in a vertical direction perpendicular to the axial direction. Specifically, the vertical direction is the direction that lifts the actuator AC upward. In other words, the driving force input to the coupling 13 is transmitted from one end of the housing 11 to the other end of the axial direction by the shaft 14A of the agitator 14.

[0050] like Figure 3As shown, the developer cartridge 1 includes an agitator gear 31 as an example of a gear, a bearing 40, a rack 50, a gear cover 60 as an example of a cover, and a developer electrode 20. The agitator gear 31, the bearing 40, the rack 50, the gear cover 60, and the developer electrode 20 are located at the other end in the axial direction of the housing 11. The housing 11, the agitator gear 31, the rack 50, and the gear cover 60 are made of a non-conductive resin.

[0051] The developing electrode 20 and the bearing 40 are made of a conductive material. Specifically, the developing electrode 20 and the bearing 40 are made of a conductive resin. The conductive resin is, for example, polyacetal resin containing carbon powder.

[0052] The agitator gear 31 is mounted on the other end of the shaft 14A of the agitator 14. The agitator gear 31 is rotatable about a second axis X2 that is parallel to the first axis X1. The agitator gear 31 rotates together with the shaft 14A of the agitator 14. In other words, the agitator gear 31 rotates together with the developing roller 12 by the driving force input to the coupling 13.

[0053] The bearing 40 is a member for rotatably supporting the shaft 12A of the developing roller 12 and the shaft 15A of the supply roller 15 . The bearing 40 includes a plate-shaped portion 41 , a first bearing portion 42 , a second bearing portion 43 , and two first guide portions 44 .

[0054] The plate-like portion 41 extends from the shaft 12A toward the shaft 14A. Specifically, the plate-like portion 41 extends from the shaft 12A of the developing roller 12 toward the agitator gear 31. The plate-like portion 41 is located between the side wall 11A at the other end of the housing 11 in the axial direction and the rack 50.

[0055] Specifically, the plate-shaped portion 41 is located in the recess 11B, which is located on the outer surface of the side wall 11A. Therefore, the outer surface of the plate-shaped portion 41 and the outer surface of the side wall 11A are substantially flush with each other (see FIG. Figure 7 ).

[0056] The first bearing 42 is a hollow cylindrical portion that rotatably supports the shaft 12A of the developing roller 12. The first bearing 42 protrudes from the plate-shaped portion 41 in the axial direction away from the housing 11. Specifically, the first bearing 42 protrudes farther from the housing 11 in the axial direction than the second bearing 43.

[0057] The second bearing 43 is a hollow cylindrical portion that rotatably supports the shaft 15A of the supply roller 15. The second bearing 43 protrudes from the plate-shaped portion 41 in the axial direction away from the housing 11. The second bearing 43 is located closer to the agitator gear 31 than the first bearing 42.

[0058] Each of the first guide portions 44 is a portion that supports the rack 50 in a manner that allows it to move in a direction from one end E10 of the housing 11 (described later) toward the other end E20 of the housing 11. The two first guide portions 44 are arranged to sandwich the rack 50 therebetween. Each first guide portion 44 supports the rack 50. Each first guide portion 44 protrudes from the plate-like portion 41 in an axial direction in a direction away from the housing 11. Each first guide portion 44 is in the shape of a plate that is perpendicular to the plate-like portion 41. Each first guide portion 44 has a first length in a direction from one end E10 of the housing 11 toward the other end E20 of the housing 11 and a second length in an axial direction. The first length is greater than the second length. Each of the first guide portions 44 is located closer to the agitator gear 31 than the second bearing portion 43.

[0059] The housing 11 includes a second guide portion 11C, a third guide portion 11D, and a fourth guide portion 11E. Each of the second guide portion 11C, the third guide portion 11D, and the fourth guide portion 11E supports the rack 50 so as to be movable from one end E10 of the housing 11 toward the other end E20 of the housing 11. The second guide portion 11C is located on the opposite side of the rack 50 from the third guide portion 11D and the fourth guide portion 11E. The second guide portion 11C extends from the third guide portion 11D to the fourth guide portion 11E, extending from the one end E10 of the housing 11 toward the other end E20 of the housing 11.

[0060] The third guide portion 11D and the fourth guide portion 11E face the surface of the rack 50 that faces the agitator gear 31. The third guide portion 11D is located closer to the developing roller 12 than the agitator gear 31. The fourth guide portion 11E is located on the opposite side of the third guide portion 11D relative to the agitator gear 31 in the direction from the one end E10 of the housing 11 toward the other end E20 of the housing 11.

[0061] The rack 50 is movable from one end E10 of the housing 11 toward the other end E20 opposite to the one end E10 of the housing 11. The rack 50 includes a body 51, a rack portion 52, and first and second protrusions 53 and 54 as examples of protrusions.

[0062] The main body 51 is in the shape of a rectangular plate and extends in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11. The rack portion 52 has a plurality of gear teeth that mesh with the agitator gear 31. The main body 51 extends in the moving direction of the rack 50. The rack portion 52 and the protrusions 53 and 54 protrude from the surface of the main body 51 facing the agitator gear 31. The rack 50 is configured to move in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11 only when the rack portion 52 is meshed with the agitator gear 31. The rack 50 is configured to stop moving when the meshing between the rack portion 52 and the agitator gear 31 is released. That is, when the agitator gear 31 rotates, the rack 50 can move in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11.

[0063] The rack portion 52 is located at the downstream portion of the body portion 51 in the moving direction of the rack 50 at the end portion of the body portion 51 that is closer to the housing 11 in the axial direction. Specifically, the rack portion 52 is located in the region of the body portion 51 from the end portion of the body portion 51 that is closer to the agitator gear 31 in the moving direction of the rack 50 to the center portion of the body portion 51 in the moving direction of the rack 50 (see FIG. Figure 4 ).

[0064] The first protrusion 53 and the second protrusion 54 are located at a different position from the rack portion 52 in the moving direction of the rack 50. The first protrusion 53 and the second protrusion 54 are located at a different position from the rack portion 52 in the axial direction. Specifically, the first protrusion 53 and the second protrusion 54 are located at a position of the main body portion 51 that is farther from the housing 11 in the axial direction than the rack portion 52. In addition, the first protrusion 53 and the second protrusion 54 are located at a position that is closer to the developing roller 12 than the rack portion 52 in the moving direction of the rack 50. More specifically, the first protrusion 53 is located near the central portion of the main body portion 51 in the moving direction of the rack 50. The second protrusion 54 is located at an end portion of the main body portion 51 that is closer to the developing roller 12 in the moving direction. The first protrusion 53 and the second protrusion 54 are capable of contacting the first cam surface 73A and the third cam surface 74A of the cam 70 in accordance with the movement of the rack 50 (see Figure 6 , described later).

[0065] The gear cover 60 covers the agitator gear 31 and the rack 50. Figure 5 As shown, the gear cover 60 covers the cam 70, the developing electrode 20, and a compression coil spring SP as an example of a spring. The cam 70 moves in the axial direction by receiving a force applied from the rack 50. The cam 70 is made of a non-conductive resin. The compression coil spring SP is made of a conductive material, specifically metal.

[0066] The gear cover 60 includes a first cover portion 61, a second cover portion 62, and a third cover portion 63. The first cover portion 61 covers the rack 50 and the agitator gear 31. The second cover portion 62 covers the cam 70 and the developer electrode 20. The third cover portion 63 covers the compression coil spring SP. The first cover portion 61 extends from one end E10 of the housing 11 toward the other end E20 of the housing 11, allowing the rack 50 to be covered by the first cover portion 61 before, during, and after movement.

[0067] The second cover portion 62 protrudes in the axial direction away from the housing 11. The second cover portion 62 protrudes from a substantially central portion of the first cover portion 61 in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11, away from the housing 11. The second cover portion 62 has an internal space that communicates with the internal space of the first cover portion 61. The second cover portion 62 also has an opening 62A, through which the development electrode 20 is exposed.

[0068] The third cover portion 63 has a through-hole 63A extending through the thickness of the third cover portion 63 in the axial direction. A compression coil spring SP is positioned within the through-hole 63A. The third cover portion 63 is located substantially at the same position as the second cover portion 62 in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11. The third cover portion 63 protrudes from the first cover portion 63 in a direction away from the rack 50. The through-hole 63A opens toward the development electrode 20.

[0069] Incidentally, in the present embodiment, the hollow portion of the third cover portion 63 is located between the outer peripheral surface of the third cover portion 63 and the through hole 63A. However, the hollow portion may not be located between the outer peripheral surface of the third cover portion 63 and the through hole 63A.

[0070] The cam 70 is located in the second cover portion 62 of the gear cover 60 so as to be movable in the axial direction. Figure 8A The first position shown and Figure 8B The second position is farther from the housing 11 in the axial direction than the first position. Figure 6 As shown, the cam 70 includes a base portion 71 , a rib 72 , a first cam portion 73 , a third cam portion 74 , a protrusion 75 and two second cam portions 76 .

[0071] The base portion 71 is a plate-shaped portion perpendicular to the direction in which the rack 50 and cam 70 face each other. The base portion 71 has a first length in the axial direction and a second length in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11. The first length is greater than the second length. Ribs 72 protrude from the end of the base portion 71 closer to the housing 11 toward the rack 50.

[0072] The first cam portion 73 and the third cam portion 74 are located between the rib 72 and the protrusion 75. The first cam portion 73 and the third cam portion 74 protrude from the base portion 71 toward the rack 50.

[0073] The first cam portion 73 is located at a different position than the third cam portion 74 in the direction of movement of the rack 50. Specifically, the first cam portion 73 is farther from the agitator gear 31 in the direction of movement of the rack 50 than the third cam portion 74. The first cam portion 73 extends obliquely from the protrusion 75 toward the rib 72. In other words, the first cam portion 73 extends obliquely from the protrusion 75 downstream in the direction of movement of the rack 50. One end of the first cam portion 73 is connected to the protrusion 75, and the other end is spaced apart from the rib 72. The space between the other end of the first cam portion 73 and the rib 72 is greater than the diameter of each of the protrusions 53 and 54 of the rack 50.

[0074] The first cam portion 73 has a first cam surface 73A that is inclined relative to the direction of movement of the rack 50. The first cam surface 73A is used to move the cam 70 axially away from the housing 11. When the cam 70 is in the first position, the first cam surface 73A is configured to contact the protrusions 53 and 54 of the rack 50. The first cam surface 73A is configured to move the cam 70 from the first position to the second position. Specifically, when the rack 50 moves from one end E10 of the housing 11 toward the other end E20 of the housing 11 while the first cam surface 73A is in contact with the first protrusion 53 or the second protrusion 54, the first cam surface 73A moves the cam 70 from the first position to the second position. In other words, the first cam surface 73A cooperates with the protrusions 53 and 54 to move the cam 70 from the first position to the second position. When the cam 70 is in the second position, the first cam surface 73A is located outside the movement path of the protrusions 53 and 54.

[0075] The first cam surface 73A is inclined so that the downstream edge of the first cam surface 73A in the direction of movement of the rack 50 is closer to the housing 11 in the axial direction than the upstream edge of the first cam surface 73A in the direction of movement of the rack 50. Specifically, the first cam surface 73A has a first edge E1 and a second edge E2. The second edge E2 is farther from the housing 11 in the axial direction than the first edge E1. The first cam surface 73A is inclined so that the first edge E1 is located downstream of the second edge E2 in the direction of movement of the rack 50.

[0076] The third cam portion 74 extends obliquely from the substantially central portion of the rib 72 in the direction from one end E10 of the housing 11 toward the other end E20 of the housing 11 toward the protrusion 75. In other words, the third cam portion 74 extends obliquely from the substantially central portion of the rib 72 toward the downstream side in the direction of movement of the rack 50. One end of the third cam portion 74 is connected to the rib 72, and the other end is spaced apart from the protrusion 75. The space between the other end of the third cam portion 74 and the protrusion 75 is greater than the diameter of each protrusion 53, 54 of the rack 50.

[0077] The third cam portion 74 has a third cam surface 74A that is inclined relative to the direction of movement of the rack 50. The third cam surface 74A is a surface for moving the cam 70 in the axial direction toward the housing 11. When the cam 70 is in the second position, the third cam surface 74A is configured to contact the protrusions 53 and 54 of the rack 50. In other words, when the cam 70 is in the second position, the third cam surface 74A is located within the movement trajectory of the protrusions 53 and 54. The third cam surface 74A is configured to move the cam 70 from the second position to the first position. Specifically, when the rack 50 moves from one end E10 of the housing 11 toward the other end E20 of the housing 11 while the third cam surface 74A is in contact with the first protrusion 53 or the second protrusion 54, the third cam surface 74A moves the cam 70 from the second position to the first position.

[0078] The third cam surface 74A is located downstream of the first cam surface 73A in the direction of movement of the rack 50. The third cam surface 74A is located at a different position from the first cam surface 73A in the direction of movement of the cam 70. Specifically, the first cam surface 73A is farther from the housing 11 in the axial direction than the third cam surface 74A.

[0079] The third cam surface 74A is inclined so that the downstream edge of the third cam surface 74A in the direction of movement of the rack 50 is farther from the housing 11 in the axial direction than the upstream edge of the third cam surface 74A in the direction of movement of the rack 50. Specifically, the third cam surface 74A has a third edge E3 and a fourth edge E4. The fourth edge E4 is farther from the housing 11 in the axial direction than the third edge E3. The third cam surface 74A is inclined so that the fourth edge E4 is located downstream from the third edge E3 in the direction of movement of the rack 50.

[0080] The protrusion 75 protrudes from a portion of the base 71 farther from the housing 11 toward the developing electrode 20. The protrusion 75 protrudes from one end of the base 71 farther from the housing 11 in the axial direction toward the first cam portion 73. The protrusion 75 has a rectangular through-hole 75B that penetrates the thickness of the protrusion 75 in the axial direction.

[0081] Each second cam portion 76 protrudes from the surface of the protrusion 75 facing the development electrode 20 toward the development electrode 20. Hereinafter, the surface of the protrusion 75 facing the development electrode 20 will also be referred to as the "first surface 75A". Each second cam portion 76 is spaced apart from each other in the axial direction. Each second cam portion 76 is spaced apart from one end and the other end of the protrusion 75 in the axial direction. Each second cam portion 76 has a second cam surface 76A inclined relative to the axial direction and a support surface 76B for supporting the development electrode 20.

[0082] The second cam surface 76A is a surface that moves the development electrode 20 in a direction away from the cam 70 when the cam 70 moves from the first position to the second position. When the cam 70 moves from the first position to the second position, the second cam surface 76A contacts the development electrode 20. The direction away from the cam 70 is a direction different from the movement direction of the rack 50 and the movement direction of the cam 70. The second cam surface 76A can move together with the first cam surface 73A. The second cam surface 76A is farther from the housing 11 in the axial direction than the first cam surface 73A.

[0083] The second cam surface 76A is inclined toward the first surface 75A. The downstream edge of the second cam surface 76A, which is axially away from the housing 11, is closer to the first surface 75A than the upstream edge of the second cam surface 76A, which is axially away from the housing 11. Specifically, the second cam surface 76A has a fifth edge E5 and a sixth edge E6. The sixth edge E6 is axially farther from the housing 11 than the fifth edge E5. The second cam surface 76A is inclined so as to protrude toward the development electrode 20 in the direction from the sixth edge E6 toward the fifth edge E5. In other words, the second cam surface 76A is inclined so as to protrude toward the opening 62A in the direction from the sixth edge E6 toward the fifth edge E5. The support surface 76B extends parallel to the first surface 75A.

[0084] return Figure 5 , the developing electrode 20 is movably supported on the second cover portion 62 of the gear cover 60. The developing electrode 20 is located on the first surface 75A of the cam 70. The developing electrode 20 is movable between a third position and a fourth position. The fourth position is farther from the cam 70 than the third position. The developing electrode 20 has an electrode portion 21 having a substantially rectangular parallelepiped shape, a first flange portion 22, and a second flange portion 23. The first flange portion 22 and the second flange portion 23 protrude from the end portion of the electrode portion 21 opposite to the second surface 21A (described later) of the electrode portion 21 in a direction away from the electrode portion 21 in the axial direction.

[0085] The electrode portion 21 moves away from the cam 70 (see Figure 3) direction through the opening 62A of the second cover portion 62. Specifically, when the development electrode 20 is located at the fourth position, the electrode portion 21 protrudes from the opening 62A by a greater amount than when the development electrode 20 is located at the third position.

[0086] The electrode portion 21 has a surface opposite to the surface facing the cam 70. Hereinafter, the surface of the electrode portion 21 opposite to the surface facing the cam 70 is also referred to as the "second surface 21A". The second surface 21A is an arcuate curved surface protruding in a direction away from the cam 70 in a cross section perpendicular to the axial direction. The electrode portion 21 has two recesses 24, and the two second cam portions 76 of the cam 70 can respectively enter the recesses 24. The recesses 24 are configured to be recessed from the surface of the electrode portion 21 facing the cam 70 in a direction away from the cam 70. Each recess 24 has a fourth cam surface 24A that contacts the second cam surface 76A of the second cam portion 76, and a bottom surface 24B extending parallel to the first surface 75A. The fourth cam surface 24A extends parallel to the second cam surface 76A.

[0087] In the surface of the electrode portion 21 facing the cam 70, the portion located between the two recesses 24 serves as a supported surface 21B. When the developing electrode 20 is in the fourth position, the supported surface 21B is supported by the second cam portion 76 of the two second cam portions 76 of the cam 70, which is closer to the housing 11. In addition, the surface of the first flange portion 22 facing the cam 70 serves as a supported surface 22A. When the developing electrode 20 is in the fourth position, the supported surface 22A is supported by the second cam portion 76 of the two second cam portions 76 of the cam 70, which is farther from the housing 11. Incidentally, when the developing electrode 20 is in the third position, at least one of the surface of the developing electrode 20 facing the cam 70 (i.e., the surface including the supported surfaces 21B and 22A) and the bottom surface 24B of each recess 24 can be supported by the cam 70.

[0088] like Figure 7 As shown, the compression coil spring SP is located between the electrode portion 21 of the developing electrode 20 and the plate-shaped portion 41 of the bearing 40 in the axial direction. Specifically, one end of the compression coil spring SP contacts the electrode portion 21 of the developing electrode 20, and the other end of the compression coil spring SP, opposite to the one end, contacts the plate-shaped portion 41 of the bearing 40. Therefore, the developing electrode 20 is electrically connected to the developing roller 12 and the supply roller 15 via the compression coil spring SP and the bearing 40.

[0089] More specifically, the compression coil spring SP is in contact with the surface of the electrode portion 21 that is closer to the housing 11. Therefore, when the development electrode 20 is located at the third position, when the development electrode 20 moves from the third position to the fourth position, and when the development electrode 20 is located at the fourth position, the compression coil spring SP remains in contact with the electrode portion 21. That is, the development electrode 20 is able to move while the development electrode 20 is in contact with the compression coil spring SP.

[0090] With one end of the compression coil spring SP in contact with the development electrode 20 and the other end of the compression coil spring SP in contact with the bearing 40, the length of the compression coil spring SP is shorter than its natural length. Furthermore, the compression coil spring SP is located on the opposite side of the rack 50 from the cam 70. The compression coil spring SP is located between the first guide portion 44 and the second guide portion 11C in the direction from the one end E10 of the housing 11 toward the other end E20 of the housing 11.

[0091] Next, the operation and effects of each component constituting the developer cartridge 1 will be described in detail. When the developer cartridge 1 is in a new state, the rack 50 is located closest to one end E10 of the housing 11, and the cam 70 is located closest to the housing 11. With this arrangement, the development electrode 20 is placed in the third position.

[0092] like Figure 2 As shown, when the new developer cartridge 1 is mounted in the main body housing of the image forming apparatus, the second surface 21A of the developer electrode 20 contacts the electrode provided on the actuator AC. Therefore, a development bias is supplied from a power source (not shown) of the image forming apparatus to the developer electrode 20 via the electrode of the actuator AC.

[0093] Thereafter, when driving force is input from a driving source (not shown) of the body housing to the coupling 13 of the developing cartridge 1, the driving force is transmitted to the shaft 14A of the agitator 14 through the coupling 13 and a gear mechanism (not shown). Figure 3 As shown, the driving force transmitted to the shaft 14A of the agitator 14 is transmitted to the agitator gear 31 .

[0094] As the agitator gear 31 to which the driving force is transmitted rotates, the rack 50 moves in a direction from one end E10 of the housing 11 toward the other end E20 of the housing 11. Figure 8A and 8B As shown in sequence, when the first protrusion 53 of the rack 50 contacts the first cam surface 73A of the cam 70 to press the first cam surface 73A according to the movement of the rack 50, the cam 70 moves in a direction away from the housing 11 in the axial direction. Figures 8A to 8D In FIG. 5 , the portion indicated by dotted hatching indicates a portion of the agitator gear 31 that can mesh with the rack portion 52 .

[0095] When the cam 70 moves in a direction away from the housing 11 in the axial direction, as shown in FIG. Figure 9A and 9B As shown in sequence, the developing electrode 20 is pushed upward by each second cam surface 76A of the cam 70, and the developing electrode 20 moves from the third position to the fourth position. In other words, the developing electrode 20 receives a force from the cam 70 moving in a direction away from the housing 11 in the axial direction, and moves in a direction away from the cam 70.

[0096] When the development electrode 20 moves to the fourth position, the actuator AC is pushed upward by the development electrode 20, changing its position. Specifically, the cam 70 applies force to the actuator AC via the development electrode 20, thereby changing the position of the actuator AC in one direction. Consequently, the optical sensor detects this change in the position of the actuator AC in one direction. The control device of the image forming apparatus can determine that the development cartridge 1 is new by detecting this change in the position of the actuator AC using the optical sensor.

[0097] like Figure 8B and 8C As shown in sequence, when the rack 50 further moves from one end E10 of the housing 11 toward the other end E20 of the housing 11, the first protrusion 53 of the rack 50 presses the third cam surface 74A of the cam 70, so that the cam 70 moves in the direction toward the housing 11 in the axial direction. Figure 9B and Figure 9A As shown in sequence, the respective support surfaces 76B of the cam 70 are separated from the respective support surfaces 21B and 22A of the development electrode 20, and the development electrode 20 moves from the fourth position to the third position. Incidentally, the movement of the development electrode 20 from the fourth position to the third position can be achieved by gravity or by a spring urging the actuator AC.

[0098] Afterwards, if Figure 8C and Figure 8DAs shown in sequence, as the rack 50 further moves from one end E10 of the housing 11 toward the other end E20 of the housing 11, the second protrusion 54 of the rack 50 sequentially applies pressure to the respective cam surfaces 73A and 74A of the cam 70. As a result, the cam 70 moves in a direction away from the housing 11 in the axial direction, and then moves in a direction toward the housing 11 in the axial direction. Therefore, after the development electrode 20 moves again to the fourth position and then returns to the third position, the optical sensor detects a position change of the actuator AC in one direction. That is, in this embodiment, after the new developer cartridge 1 is installed in the main body housing of the image forming apparatus, the optical sensor detects two position changes of the actuator in one direction. This corresponds to the number of protrusions 53 and 54 on the rack 50. For example, if the rack 50 includes only one protrusion, the number of position changes of the actuator in one direction detected by the optical sensor is one. Therefore, the control device can also determine the specification of the developing cartridge 1 by setting the number of protrusions of the rack 50 according to the specification of the developing cartridge 1 (for example, the difference in the amount of toner accommodated in the developing cartridge 1 ).

[0099] In such Figure 8D After the second protrusion 54 is separated from the third cam surface 74A, the meshing between the rack 50 and the agitator gear 31 is released. As a result, the transmission of the driving force from the agitator gear 31 to the rack 50 is cut off, and the development electrode 20 is held at the third position.

[0100] According to the above description, this embodiment can obtain the following effects.

[0101] Since the rack 50 moves in the direction from the one end E10 of the housing 11 toward the other end E20 of the housing 11 , the meshing between the rack 50 and the agitator gear 31 can be released.

[0102] Since the developing electrode 20 is formed of a conductive resin, the shape of the developing electrode 20 can be easily formed.

[0103] <Second embodiment>

[0104] Next, we will refer to Figures 10-13B The developing cartridge 101 according to the second embodiment will be described, wherein similar components are denoted by the same reference numerals as those of the first embodiment to avoid duplication of description. In the following description, only the parts different from the first embodiment will be described in detail.

[0105] In the first embodiment, the compression coil spring SP is constructed as a member separate from the developing electrode 20. However, in the second embodiment, the spring and the developing electrode 20 are formed as a separate member. Figure 10Specifically, in the second embodiment, in addition to the housing 11, the agitator gear 31 and the bearing 40 similar to those of the first embodiment, the developing cartridge 101 includes a rack 150, a cam 170 and a spring electrode 80 different from those of the first embodiment. Figure 11A As shown, the cam 170 includes a base 71, a protrusion 75, a protrusion 77, and a spring support 78. The protrusion 77 and the spring support 78 of the cam 170 are not included in the cam 70 according to the first embodiment, and the base 71 and the protrusion 75 of the cam 170 are similar to those of the cam 70 of the first embodiment.

[0106] The protrusion 77 protrudes from the end of the base 71 closer to the housing 11 toward the spring electrode 80. The protrusion 77 is semi-cylindrical. The surface of the protrusion 77 farther from the housing 11 is an arcuate curved surface protruding in a direction away from the housing 11 in the axial direction.

[0107] The spring support portion 78 protrudes from the first surface 75A of the protrusion 75 toward the spring electrode 80. The spring support portion 78 has a surface facing the spring electrode 80. The surface of the spring support portion 78 facing the spring electrode 80 includes a first flat surface 78A, a second flat surface 78B, and an inclined surface 78C. The inclined surface 78C connects the first flat surface 78A and the second flat surface 78B. The first flat surface 78A and the second flat surface 78B extend parallel to the base 71. The first flat surface 78A is farther from the base 71 than the second flat surface 78B. The first flat surface 78A is located closer to the housing 11 than the second flat surface 78B. The inclined surface 78C extends from the edge of the first flat surface 78A farther from the housing 11. The inclined surface 78C connects to the edge of the second flat surface 78B closer to the housing 11. The inclined surface 78C is inclined so that a downstream edge of the inclined surface 78C in the axial direction away from the housing 11 is closer to the base 71 than an upstream edge of the inclined surface 78C in the axial direction away from the housing 11 .

[0108] The spring support portion 78 has a recessed portion 78D. The recessed portion 78D is recessed toward the base portion 71 in the center of each of the surfaces 78A, 78B, and 78C, extending from one end E10 of the housing 11 toward the other end E20 of the housing 11. The recessed portion 78D is located between the edge of the first flat surface 78A closer to the housing 11 and the edge of the second flat surface 78B farther from the housing 11. Furthermore, the spring support portion 78 has a side surface 78E closer to the housing 11. The spring support portion 78 includes an engaging claw 78F located on and protruding from the side surface 78E.

[0109] The through hole 63A of the third cover portion 63 of the gear cover 60 is formed to have a size corresponding to the spring electrode 80 .

[0110] The spring electrode 80 is made of a conductive material. The spring electrode 80 is electrically connected to the developing roller 12. The spring electrode 80 is movable together with the cam 170. The spring electrode 80 includes a developing electrode 81 and a spring 82. The developing electrode 81 has a shape that matches the shape of the spring support portion 78. The spring 82 is formed integrally with the developing electrode 81.

[0111] The development electrode 81 includes a first plate-shaped portion 81A, a second plate-shaped portion 81B, a third plate-shaped portion 81C, a fourth plate-shaped portion 81D, and a fifth plate-shaped portion 81E. The first plate-shaped portion 81A and the second plate-shaped portion 81B extend parallel to the base portion 71. The third plate-shaped portion 81C connects the first plate-shaped portion 81A and the second plate-shaped portion 81B. The fourth plate-shaped portion 81D extends from the end of the first plate-shaped portion 81A closer to the housing 11 toward the base portion 71. The fifth plate-shaped portion 81E extends from the end of the second plate-shaped portion 81B farther from the housing 11 toward the base portion 71.

[0112] The first plate-shaped portion 81A, the second plate-shaped portion 81B, and the third plate-shaped portion 81C are accommodated in the recess 78D of the spring support portion 78 and are located on the bottom surface of the recess 78D. When the first plate-shaped portion 81A is located on the bottom surface of the recess 78D, the surface of the first plate-shaped portion 81A opposite the surface facing the cam 170 is flush with the first flat surface 78A of the spring support portion 78. When the second plate-shaped portion 81B is located on the bottom surface of the recess 78D, the surface of the second plate-shaped portion 81B opposite the surface facing the cam 170 is flush with the second flat surface 78B of the spring support portion 78. When the third plate-shaped portion 81C is located on the bottom surface of the recess 78D, the surface of the third plate-shaped portion 81C opposite the surface facing the cam 170 is flush with the inclined surface 78C of the spring support portion 78. Alternatively, when the first plate-shaped portion 81A is located at the bottom of the recess 78D, the surface of the first plate-shaped portion 81A opposite the surface facing the cam 170 is located further from the base 71 than the first flat surface 78A of the spring support portion 78. When the second plate-shaped portion 81B is located at the bottom of the recess 78D, the surface of the second plate-shaped portion 81B opposite the surface facing the cam 170 is located further from the base 71 than the second flat surface 78B of the spring support portion 78. When the third plate-shaped portion 81C is located at the bottom of the recess 78D, the surface of the third plate-shaped portion 81C opposite the surface facing the cam 170 is located further from the base 71 than the inclined surface 78C of the spring support portion 78. Furthermore, the surface of the third plate-shaped portion 81C, which is inclined relative to the axial direction and opposite the surface facing the cam 170, serves as a second cam surface 81G.

[0113] The second cam surface 81G has a fifth edge E105 and a sixth edge E106. The sixth edge E106 is farther from the housing 11 in the axial direction than the fifth edge E105. The second cam surface 81G is inclined to protrude toward the opening 62A in a direction from the sixth edge E106 toward the fifth edge E105.

[0114] The fourth plate-shaped portion 81D and the fifth plate-shaped portion 81E sandwich the spring support portion 78 in the axial direction. The engaging hole 81F engages with the engaging claw 78F of the spring support portion 78. The fourth plate-shaped portion 81D has the engaging hole 81F.

[0115] The spring 82 includes a flat plate portion 82A, a first curved portion 82B, and a second curved portion 82C. The flat plate portion 82A extends parallel to the first flat plate portion 81A. The first curved portion 82B is curved to protrude away from the cam 170. The second curved portion 82C is curved to protrude toward the housing 11. The flat plate portion 82A extends toward the housing 11 from the end of the fourth flat plate portion 81D that is closer to the cam 170. The first curved portion 82B is connected to the end of the flat plate portion 82A that is closer to the housing 11. The second curved portion 82C extends from the end of the first curved portion 82B that is closer to the housing 11 in a direction away from the cam 170.

[0116] like Figure 13A As shown, the spring 82 is located between the side surface 78E of the spring support portion 78 and the bearing 40. A portion of the spring 82 closer to the housing 11 contacts the bearing 40. When the cam 170 is in its initial position (ie, Figure 13A 1 ), the spring 82 urges the cam 170 in a direction away from the housing 11 in the axial direction. In other words, the spring 82 urges the cam 170 from the initial position, which is an example of the first position, toward the outer position, which is an example of the second position.

[0117] like Figure 11B As shown, the rack 150 includes a body portion 51, a rack portion 52, and a cam portion 55. The cam portion 55 is not included in the rack 50 according to the first embodiment. The body portion 51 and the rack portion 52 of the rack 150 are similar to those of the rack 50 of the first embodiment. The cam portion 55 is located upstream of the rack 150 in the direction of movement of the rack 150 at the end of the body portion 51 farther from the housing 11 in the axial direction. In the following description, "upstream in the direction of movement of the rack" and "downstream in the direction of movement of the rack" will be referred to as "upstream" and "downstream," respectively.

[0118] The cam portion 55 protrudes from the main body 51. The surface of the cam portion 55 closer to the housing 11 includes a first retaining surface 55A, a second retaining surface 55B, a third retaining surface 55C, a connecting surface 55D, and a cam surface 55E. The first retaining surface 55A, the second retaining surface 55B, and the third retaining surface 55C are planes perpendicular to the axial direction. The connecting surface 55D connects the first retaining surface 55A and the second retaining surface 55B. The cam surface 55E connects the second retaining surface 55B and the third retaining surface 55C.

[0119] The first retaining surface 55A and the third retaining surface 55C are located at the same position as each other in the axial direction. The first retaining surface 55A is located downstream relative to the third retaining surface 55C. The first retaining surface 55A and the third retaining surface 55C contact the protrusion 77 to retain the cam 170 in the initial position (first position).

[0120] The second holding surface 55B is located between the first holding surface 55A and the third holding surface 55C in the moving direction of the rack 150. The second holding surface 55B is located farther from the housing 11 than the first holding surface 55A (see FIG. Figure 12A ). The second holding surface 55B contacts the protrusion 77 to hold the cam 170 at the outer position (second position).

[0121] The connecting surface 55D extends from the upstream edge of the first holding surface 55A and connects to the downstream edge of the second holding surface 55B. The connecting surface 55D is inclined so that the upstream edge of the connecting surface 55D is farther from the housing 11 than the downstream edge of the connecting surface 55D.

[0122] The cam surface 55E is inclined relative to the direction of movement of the rack 150. Specifically, the cam surface 55E extends from the upstream edge of the second retaining surface 55B and connects to the downstream edge of the third retaining surface 55C. The cam surface 55E is inclined so that the upstream edge of the cam surface 55E is located closer to the housing 11 than the downstream edge of the cam surface 55E.

[0123] In this embodiment, if Figure 12A As shown, when the developing cartridge 1 is in a new state, the cam 170 is located in its initial position because the protrusion 77 of the cam 170 is supported on the first holding surface 55A of the rack 150. Specifically, the force applied to the cam 170 from the spring electrode 80 is received by the first holding surface 55A.

[0124] When the developing cartridge 1 is mounted to the main body housing of the image forming apparatus with the cam 170 located at the initial position, as shown in FIG. Figure 13AAs shown, actuator AC is pushed by second plate-shaped portion 81B of spring electrode 80, which is supported on cam 170. As a result, actuator AC swings from its first position to its second position. The optical sensor detects this change in actuator AC's position. At this point, the electrodes of actuator AC and spring electrode 80 are electrically connected.

[0125] Afterwards, if Figure 12A and 12B As shown in this order, when the driving force is transmitted to the agitator gear 31, the rack 150 moves in a direction from one end E10 of the housing 11 toward the other end E20 of the housing 11. When the first retaining surface 55A separates from the protrusion 77 in response to the movement of the rack 150, the cam 170 moves in a direction away from the housing 11 in the axial direction due to the force applied by the spring electrode 80. Thereafter, when the protrusion 77 contacts the second retaining surface 55B, the movement of the cam 170 stops, and the cam 170 is located further outward from the housing 11 than its initial position.

[0126] When the cam 170 moves from the initial position to the outer position, the actuator AC is pushed by the inclined third plate portion 81C of the spring electrode 80 supported on the cam 170. Figure 13B As a result, the actuator AC swings from the second posture to the third posture, and the optical sensor detects the posture change of the actuator AC.

[0127] Afterwards, if Figure 12B and 12C As shown in the sequence, when the rack 150 further moves in the direction from the one end E10 of the housing 11 to the other end E20 of the housing 11, the protrusion 77 is pushed by the cam surface 55E of the rack 150 in the direction toward the housing 11 in the axial direction against the force applied by the spring electrode 80, so that the cam 170 returns to the initial position from the outer position. As a result, the actuator AC swings from the third posture to the second posture, as shown in FIG. Figure 13A As shown, the optical sensor detects the posture change of the actuator AC.

[0128] As described above, in the second embodiment, similar to the first embodiment, the rack 150 moves in a direction from one end E10 of the housing 11 toward the other end E20 of the housing 11, thereby releasing the meshing between the rack 150 and the agitator gear 31. Furthermore, in the second embodiment, the spring 82 and the development electrode 81 are configured as a single component (the spring electrode 80), thereby reducing the number of components. The spring and the development electrode may be separate components. Furthermore, the spring as a separate component may be a coil spring or a wire spring.

[0129] <Modification>

[0130] While the present invention has been described in detail with reference to the embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the present invention.

[0131] In the first embodiment, the fourth cam surface 24A is provided at the development electrode 20, and the second cam surface 76A is provided at the cam 70. However, for example, a protrusion that cooperates with the second cam surface of the cam may be provided at the development electrode.

[0132] In the first embodiment, the rack 50 is entirely covered by the gear cover 60. However, the gear cover may cover a portion of the rack, leaving the remaining portion of the rack exposed.

[0133] In the first and second embodiments, the agitator gear 31 is used as an example of a gear. However, in addition to the agitator gear 31, other gears may be used.

[0134] In the first and second embodiments, the compression coil spring SP and the spring 82 are examples of the spring. However, the spring may be, for example, a wire spring or a torsion spring.

[0135] In the first embodiment, the cam 70 is movably supported by the gear cover 60. However, the cam may be movably supported by the housing.

[0136] Furthermore, each component in the above-described embodiment and modified examples may be arbitrarily combined and implemented.

Claims

1. A developing cartridge, comprising: a housing configured to accommodate toner therein; a developing roller rotatable about a first axis extending in an axial direction, the developing roller being located at a first end of the housing; a developing electrode electrically connected to the developing roller; a gear rotatable about a second axis parallel to the first axis; a rack meshed with the gear, the rack being movable along a direction extending between the first end of the housing and a second end of the housing opposite to the first end, the rack including a protrusion; and A cam is movable between a first position and a second position, the cam having a first cam surface configured to cooperate with the protrusion to selectively move the cam between the first position and the second position in response to movement of the rack.

2. The developing cartridge according to claim 1, wherein The rack is movable in a direction extending from the first end of the housing toward the second end of the housing, thereby moving the cam from the first position to the second position.

3. The developing cartridge according to claim 1, wherein The cam also has a second cam surface that moves the development electrode in a direction away from the cam in response to the cam moving from the first position to the second position.

4. The developing cartridge according to claim 1, wherein: The second position is farther from the housing in the axial direction than the first position.

5. The developing cartridge according to claim 1, wherein The cam is configured to move the development electrode in a direction away from the cam in response to the cam moving from the first position to the second position, the direction away from the cam being a direction different from a moving direction of the rack and a moving direction of the cam.

6. A developing cartridge comprising: a housing configured to accommodate toner therein; a developing roller rotatable about a first axis extending in an axial direction, the developing roller being located at a first end of the housing; a developing electrode electrically connected to the developing roller; a gear rotatable about a second axis parallel to the first axis; a rack meshing with the gear, the rack comprising a protrusion; and A cam capable of moving from a first position to a second position, the cam having a first cam surface that contacts the protrusion when the cam is in the first position, and the first cam surface causes the cam to move from the first position to the second position when the rack moves along a direction extending between the first end of the housing and the second end of the housing opposite to the first end.

7. The developing cartridge according to claim 6, wherein: When the rack moves in a direction extending from the first end of the housing toward the second end of the housing, the protrusion contacts the first cam surface.

8. The developing cartridge according to claim 6, wherein: The second position is farther from the housing in the axial direction than the first position.

9. The developing cartridge according to claim 6, wherein: The cam also has a second cam surface, which moves the developing electrode in a direction away from the cam while contacting the developing electrode when the cam moves from the first position to the second position. The direction away from the cam is a direction different from the moving direction of the rack and the moving direction of the cam.

10. A developing cartridge comprising: a housing configured to accommodate toner therein; a developing roller rotatable about a first axis extending in an axial direction, the developing roller being located at one end of the housing; a developing electrode electrically connected to the developing roller; a gear rotatable about a second axis parallel to the first axis; a rack meshing with the gear and movable along a direction extending between the one end of the housing and the other end of the housing opposite to the one end; as well as A cam is movable from a first position to a second position, and when the rack moves along the direction extending between the one end of the housing and the other end of the housing, the cam moves between the first position to the second position to move the developing electrode.

11. The developing cartridge according to claim 10, wherein: The rack includes a protrusion and the cam includes a cam surface, and when the rack moves along the direction extending between the one end of the housing and the other end of the housing, the cam surface is contacted by the protrusion, thereby causing the cam to move from the first position to the second position.

12. The developing cartridge according to claim 11, wherein: When the cam moves from the first position to the second position, the cam moves the developing electrode in a direction away from the cam.

13. The developing cartridge according to claim 10, wherein: The second position is farther from the housing in the axial direction than the first position.

14. The developing cartridge according to claim 10, wherein: The cam also includes a cam surface, which is configured to cause the developing electrode to move in a direction away from the cam when the cam moves from the first position to the second position, and the direction away from the cam is a direction different from the moving direction of the rack and the moving direction of the cam.

Images