Developing cartridge

Abstract

A developing cartridge makes a cover of a shaft of a developing roller less likely to be detached from a case. A developing roller (3) has a shaft (31) extending in an axial direction. A shaft cover (4) covers an end portion of one side in the axial direction of the shaft (31). The case (2) has a first protrusion (24) projecting in a direction crossing the axial direction. The shaft cover (4) has a hole into which the shaft (31) is fitted, an arm (43), and a second protrusion (44). The arm (43) is elastically deformable. The second protrusion (44) projects from the arm (43). The second protrusion (44) is located at a position away from a free end (43B) by a prescribed distance in the axial direction. The second protrusion (44) is engaged with the first protrusion (24). A portion of the arm (43) between the first protrusion (24) and the free end (43B) is opposite to the first protrusion (24) in an opposite direction crossing the axial direction. A fixed end (43A) is located at a position separated from the first protrusion (24) in the opposite direction.

Description

Technical Field

[0001] The present invention relates to a developing cartridge for an image forming apparatus. Background Technology

[0002] A developing cartridge having a developing roller is known. The developing cartridge of Patent Document 1 has a second collar as a cover covering the end of the developing roller shaft. A gear cover has a second engaging portion for retaining the second collar in a hook shape. The second collar can be removed from the gear cover by flexing the second engaging portion with a jig.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2023-111253.

[0006] [The problem the invention aims to solve]

[0007] However, it is desirable that the cover of the developing roller should not easily fall off except when intentionally removed. Summary of the Invention

[0008] Therefore, the object of the present invention is to make the shaft cover of the developing roller less likely to fall off the housing.

[0009] [Methods used to solve problems]

[0010] The developing cartridge of the first embodiment of the present invention includes a developing roller, a housing, and a shaft cover.

[0011] The developing roller has a shaft that extends axially.

[0012] The shaft cover covers one end of the shaft along its axial direction.

[0013] The housing has a first protrusion that extends in a direction intersecting the axial direction.

[0014] The shaft cover has a hole, an arm, and a second protrusion for the shaft to be inserted.

[0015] The arm has a fixed end and a free end located axially opposite the fixed end. The arm is capable of elastic deformation.

[0016] The second protrusion protrudes from the arm. The second protrusion is located at a predetermined distance axially away from the free end. The second protrusion engages with the first protrusion.

[0017] A portion of the arm between the first protrusion and the free end is opposite to the first protrusion in a direction that intersects the axial direction.

[0018] In the opposite direction, the fixed end is located in a position separated from the first protrusion.

[0019] The second protrusion of the shaft cover engages with the first protrusion of the housing. Furthermore, the fixed end of the arm is positioned separate from the first protrusion in a direction opposite to the first protrusion on a portion of the arm. Therefore, when the shaft cover is to be moved axially away from the housing, a portion of the arm is pressed against the first protrusion. Thus, unless the arm is intentionally bent, the shaft cover is not easily detached from the housing.

[0020] The second type of developing cartridge can also be, in the first type of developing cartridge, wherein the housing includes: a toner cartridge that holds toner; and a gear cover located on one side of the toner cartridge along its axial direction. A first protrusion may also protrude from the gear cover.

[0021] The third type of developing cartridge can also be, in the first type of developing cartridge, in which, with the shaft cover assembled to the shaft, the arm flexes, and a part of the arm abuts against the first protrusion by the elasticity of the arm.

[0022] Part of the arm abuts against the first protrusion through elasticity, making the bearing cap more difficult to detach.

[0023] The fourth type of developing cartridge can also be, in any of the first to third types of developing cartridges, the portion of the arm from the fixed end to the second protrusion is bent.

[0024] When the arm bends, stress concentration is unlikely to occur. Therefore, the arm has high durability.

[0025] The fifth type of developing cartridge can also be, in the first type of developing cartridge, where the end face of the free end relative to one side of the axial direction of the cover is located on the other side of the axial direction.

[0026] By ensuring that the free end does not protrude from one end face of the axial direction of the cover, the arm is unlikely to come into contact with external objects, thus preventing accidental deflection of the arm.

[0027] The sixth type of developing cartridge can also be, in the first type of developing cartridge, the axial side of the first protrusion is inclined relative to the axial direction in such a way that it is located on the other side of the axial direction as it approaches the arm.

[0028] When one side of the first protrusion is inclined relative to the axial direction, the arm is prone to flexing due to the inclined surface of the first protrusion when assembling the shaft cover to the housing.

[0029] The seventh type of developing cartridge can also be a developing cartridge in which the elastic modulus of the material of the shaft cover is smaller than that of the material of the first protrusion, as in the first type of developing cartridge.

[0030] When the elastic modulus of the shaft cover material is low, the arm is prone to bending.

[0031] The eighth type of developing cartridge can also be, in the first type of developing cartridge, a housing having a base wall and a retaining wall. The base wall extends in a direction intersecting the axial direction. The retaining wall protrudes from the base wall in one direction toward the axial direction. A first protrusion may also protrude from the retaining wall. Furthermore, the retaining wall may have a first surface where the first protrusion is located and a second surface on the side opposite to the first surface.

[0032] Furthermore, the shell may also have ribs on a second surface that connects the base wall and the retaining wall.

[0033] The ribs connect the base wall and the second surface of the retaining wall, increasing the rigidity of the retaining wall. This makes it difficult for the first protrusion to move.

[0034] The ninth type of developing cartridge can also be, in the first type of developing cartridge, wherein the housing has a boss. The boss protrudes axially from the base wall. The boss is connected to a rib.

[0035] The shaft cover may also have a second hole for the boss to be inserted.

[0036] The boss is inserted through the second hole of the shaft cover, and the shaft cover is positioned relative to the housing in a specified orientation.

[0037] [The effects of the invention]

[0038] According to the present invention, the cover of the developing roller shaft is not easily detached from the housing. Attached Figure Description

[0039] Figure 1 This is a 3D view of the developing chamber.

[0040] Figure 2 This is a perspective view showing one end of the developing cartridge along its axial direction with the shaft cover removed.

[0041] Figure 3 This is a 3D view of the shaft cover.

[0042] Figure 4 yes Figure 1 XX sectional view.

[0043] Figure 5 This refers to the process of assembling the axle cap onto the axle, and... Figure 1 The diagram corresponding to the XX cross section.

[0044] Figure 6 This indicates the state of stretching the bearing cap in one axial direction, and... Figure 1 The diagram corresponding to the XX cross section.

[0045] Symbol Explanation

[0046] 1. Developing box

[0047] 2. Shell

[0048] 3. Developing roller

[0049] 4. Shaft cover

[0050] 10-color powder box

[0051] 20 Gear Cover

[0052] 24 First protrusion

[0053] 31 axes

[0054] 41 holes

[0055] 43 arms

[0056] 43A Fixed End

[0057] 43B Free End. Detailed Implementation

[0058] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0059] like Figure 1 As shown, the developing cartridge 1 of the present invention includes a housing 2, a developing roller 3, a shaft cover 4, and a connector 5. The developing cartridge 1 is used in an image forming apparatus of an electrophotographic method.

[0060] The developing roller 3 has a shaft 31 and a roller body 32. The shaft 31 extends axially. The roller body 32 is a rubber layer covering the shaft 31. The end of the shaft 31 protrudes axially from the housing 2. The end of the shaft 31 has a cylindrical shape. The developing roller 3 has a developing roller gear G3 at the end of the shaft 31.

[0061] The housing 2 includes a toner cartridge 10 and a gear cover 20. The toner cartridge 10 contains toner. The gear cover 20 is located on one side of the toner cartridge 10 along its axial direction.

[0062] The shaft cover 4 covers one end of the shaft 31 along its axial direction.

[0063] The connector 5 is rotatably supported on the gear cover 20. The connector 5 protrudes from the axially facing side of the gear cover 20. Rotational driving force is input to the connector 5 from the image forming apparatus.

[0064] like Figure 2 As shown, the connector 5 integrally includes a connector gear G5. The connector gear G5 meshes with the developing roller gear G3 via one or more gears. The connector gear G5 and the developing roller gear G3 can also mesh directly. The developing roller gear G3 and the connector gear G5 are supported by the toner cartridge 10 and the gear cover 20 for rotation. The gear cover 20 covers the developing roller gear G3 and the connector gear G5.

[0065] The housing 2 has a base wall 21, a retaining wall 23, a first protrusion 24, a rib 25, and a boss 26. More specifically, the gear cover 20 has a base wall 21, a retaining wall 23, a first protrusion 24, a rib 25, and a boss 26. The material of the gear cover 20 is, for example, ABX resin.

[0066] Base wall 21 is a wall that extends in a direction intersecting the axial direction. As an example, base wall 21 is orthogonal to the axial direction.

[0067] The retaining wall 23 protrudes axially from the base wall 21. In this embodiment, Figure 2 The direction the arrow points to on the paper above is considered one side of the axial direction. For example, retaining wall 23 has a rectangular cross-sectional shape. Retaining wall 23 extends straight along the axial direction.

[0068] A first protrusion 24 protrudes from the gear cover 20. Specifically, the first protrusion 24 protrudes from the retaining wall 23. The first protrusion 24 protrudes in a direction intersecting the axial direction. As an example, the first protrusion protrudes in a direction intersecting the axial direction. The first protrusion 24 protrudes toward the shaft 31.

[0069] Rib 25 extends in a manner that connects base wall 21 and retaining wall 23.

[0070] The boss 26 protrudes axially from the base wall 21. The boss 26 is connected to the rib 25.

[0071] The shaft cover 4 has a hole 41, a second hole 42, an arm 43 and a second protrusion 44.

[0072] like Figure 3 As shown, the shaft cover 4 has a cylindrical portion 40A, a first wall 40B, a second wall 40C, a third wall 40D, and a bridge portion 40E. The cylindrical portion 40A has a cylindrical shape. The hole 41 in the cylindrical portion 40A is a hole with a circular cross-section. The hole 41 is for inserting the end of the shaft 31. The first wall 40B and the second wall 40C extend from the cylindrical portion 40A in a direction intersecting the axial direction. The first wall 40B and the second wall 40C are curved. The first wall 40B and the second wall 40C extend at approximately a certain interval from each other. The second hole 42 is the portion between the first wall 40B and the second wall 40C. The second hole 42 is for inserting the boss 26. Thus, the shaft cover 4 is positioned at both the shaft 31 and the boss 26. The third wall 40D connects the top ends of the first wall 40B and the second wall 40C. The bridge portion 40E connects the first wall 40B and the second wall 40C at a position separate from the cylindrical portion 40A and the third wall 40D.

[0073] like Figure 4As shown, arm 43 has a fixed end 43A and a free end 43B. The free end 43B is located on one side of the axial direction relative to the fixed end 43A. Arm 43 is capable of elastic deformation. The material of the shaft cover 4 is, for example, POM resin. That is, the elastic modulus of the material of the shaft cover 4 is smaller than the elastic modulus of the material of the first protrusion 24. Therefore, arm 43 is more prone to flexing than retaining wall 23. When the shaft cover 4 is assembled to shaft 31, arm 43 flexes, and a portion of the arm abuts against the first protrusion 24 by the elastic force of arm 43.

[0074] The second protrusion 44 protrudes from the arm 43. The second protrusion 44 is located at a predetermined distance axially away from the free end 43B. The second protrusion 44 engages with the first protrusion 24. Specifically, as... Figure 6 As shown, when the shaft cover 4 moves away from the base wall 21, the second protrusion 44 engages with the first protrusion 24.

[0075] return Figure 4 A portion of the arm 43 between the first protrusion 24 and the free end 43B is designated as the tip portion 43C of the arm 43. The tip portion 43C is opposite to the first protrusion 24 in a direction intersecting the axial direction. In this embodiment, the relative direction is the direction between the center of the connecting shaft 31 and the first protrusion 24. In this embodiment, the relative direction is orthogonal to the axial direction. The fixed end 43A is located at a distance D1 from the first protrusion 24 in the relative direction. The portion of the arm 43 from the fixed end 43A to the second protrusion 44 is bent. Specifically, the portion from the fixed end 43A to the second protrusion 44 is bent in a manner that protrudes toward the base wall 21. The end face 4F of the free end 43B relative to one side of the axial direction of the shaft cover 4 is located on the other side of the axial direction. In other words, the free end 43B of the arm 43 does not protrude axially from the end face 4F.

[0076] The axial side of the first protrusion 24 is an inclined surface 24A that is tilted relative to the axial direction as it approaches the arm 43 and is located on the opposite side of the axial direction. When the shaft cover 4 is assembled to the shaft 31, the inclined surface 24A contacts the second protrusion 44, making it easy for the arm 43 to flex. Similarly, the axial side of the second protrusion 44 is an inclined surface 44A that is tilted relative to the axial direction as it approaches the retaining wall 23. When the shaft cover 4 is assembled to the shaft 31, the inclined surface 44A contacts the first protrusion 24, making it easy for the arm 43 to flex.

[0077] The retaining wall 23 has a first surface 23A and a second surface 23B. The first surface 23A is opposite to the arm 43. A first protrusion 24 is located on the first surface 23A. The second surface 23B is the surface opposite to the first surface. Figure 2 As shown, rib 25 connects the base wall 21 and the second surface 23B of the retaining wall 23.

[0078] The function and effect of the developing cartridge 1 constructed as described above will be explained. Figure 5 As shown, when assembling the shaft cover 4 to the shaft 31, the shaft 31 is inserted into the hole 41. When the shaft cover 4 is pushed axially towards the housing 2, the second protrusion 44 of the arm 43 abuts against the first protrusion 24. At this time, the inclined surface 44A of the second protrusion 44 contacts the inclined surface 24A of the first protrusion 24, and the arm 43 flexes towards the shaft 31. Since the rib 25 connects the base wall 21 and the second surface 23B of the retaining wall 23, the retaining wall 23 has high rigidity. As a result, the first protrusion 24 is difficult to move. On the other hand, since the elastic modulus of the material of the arm 43 is smaller than that of the material of the retaining wall 23, the arm 43 is easy to flex. The arm 43 generates bending stress due to flexure, but since the part from the fixed end 43A to the second protrusion 44 is bent, it is difficult for stress concentration to occur. Therefore, the arm 43 has high durability.

[0079] When the shaft cover 4 is further pushed axially toward the housing 2, the second protrusion 44 of the arm 43 passes over the first protrusion 24. Then, through the elastic force of the arm 43, the arm 43 flexes back, and the second protrusion 44 of the shaft cover 4 engages with the first protrusion 24. Through the engagement of the second protrusion 44 with the first protrusion 24, the shaft cover 4 is assembled so as not to detach from the housing 2. Figure 4 As shown, when the bearing cap 4 is pushed in the opposite axial direction to the housing 2, the free end 43B does not protrude from the end face 4F of the bearing cap 4 on one side of the axial direction. Therefore, the arm 43 is unlikely to come into contact with external objects, thus preventing accidental deflection of the arm 43. Furthermore, in the assembled state, the tip 43C of the arm 43 abuts against the first protrusion 24 by elastic force, making it even more difficult for the bearing cap 4 to detach. Additionally, the bearing cap 4 is positioned relative to the housing 2 in a predetermined orientation by inserting the boss 26 through the second hole 42 of the bearing cap 4.

[0080] Although the illustration is omitted, when intentionally removing the shaft cover 4, the top end 43C of the arm 43 is bent toward the shaft 31 using a jig. Thus, if the engagement between the second protrusion 44 and the first protrusion 24 is released, the shaft cover 4 can be pulled out axially from the shaft 31.

[0081] like Figure 6 As shown, if the shaft cover 4 is to be pulled out without intentionally bending the arm 43, the second protrusion 44 abuts against the first protrusion 24. At this time, as indicated by the arrow in the figure, a force F is applied from the first protrusion 24 to the second protrusion 44. As described above, the fixed end 43A of the arm 43 is located separated from the first protrusion 24 in the opposite direction. Therefore, when the shaft cover 4 is to be moved axially away from the housing 2, a torque is generated on the arm 43 due to the force F. Through this torque, the tip 43C of the arm 43 is pressed against the first protrusion 24. Therefore, the shaft cover 4 is not easily detached from the housing 2 unless the arm 43 is intentionally bent.

[0082] The above describes one embodiment of the present invention, but the present invention is not limited to the above embodiment and can be implemented with appropriate modifications.

[0083] In the above embodiment, the gear cover 20 has a retaining wall, but the toner cartridge 10 may also have a retaining wall. Alternatively, other components such as bearings may also have retaining walls.

[0084] Furthermore, the retaining wall 23 is located on one side of the toner cartridge 10 along its axial direction, but it can also be located on the other side of the toner cartridge 10. In other words, the shaft cover 4 of the above embodiment covers one end of the shaft 31 along its axial direction, but the same structure can also be used for a shaft cover that covers the other end of the shaft 31 along its axial direction.

[0085] Arm 43 may not abut against the first protrusion 24. Alternatively, arm 43 may be straight or L-shaped, instead of being curved from the fixed end 43A to the second protrusion 44.

[0086] The first protrusion 24 may also not have an inclined surface 24A. The second protrusion 44 may also not have an inclined surface 44A.

[0087] The free end 43B can also protrude axially from the end face 4F.

[0088] The elastic modulus of the material of the shaft cover 4 can also be greater than that of the material of the first protrusion 24. Ribs 25 may also be absent. Bosses 26 may also be absent.

[0089] Alternatively, the elements described in the above embodiments and variations can be combined in any way.

Claims

1. A developing cartridge, characterized in that, have: A developing roller having a shaft extending axially; Casing; and A shaft cover that covers one end of the shaft along its axial direction. The housing has a first protrusion projecting in a direction intersecting the axial direction. The shaft cover has: A hole for the shaft to be inserted; An arm capable of elastic deformation, having a fixed end and a free end, the free end being located on one side of the axial direction relative to the fixed end; as well as A second protrusion, which protrudes from the arm and is located at a predetermined distance from the free end along the axial direction, engages with the first protrusion. A portion of the arm between the first protrusion and the free end is opposite to the first protrusion in a direction intersecting the axial direction. In the relative direction, the fixed end is located at a position separated from the first protrusion.

2. The developing cartridge as described in claim 1, characterized in that, The housing includes a toner cartridge and a gear cover. The toner cartridge contains toner, and the gear cover is located on one side of the toner cartridge along its axial direction. The first protrusion protrudes from the gear cover.

3. The developing cartridge as described in claim 1, characterized in that, With the shaft cover assembled to the shaft, the arm flexes, and a portion of the arm abuts against the first protrusion by the elasticity of the arm.

4. The developing cartridge according to any one of claims 1 to 3, characterized in that, The portion of the arm from the fixed end to the second protrusion is bent.

5. The developing cartridge as described in claim 1, characterized in that, The end face of the free end relative to one side of the axial direction of the shaft cover is located on the other side of the axial direction.

6. The developing cartridge as described in claim 1, characterized in that, The face of the first protrusion on one side of the axial direction is inclined relative to the axial direction in such a way that it is located on the other side of the axial direction as it approaches the arm.

7. The developing cartridge as described in claim 1, characterized in that, The elastic modulus of the material of the shaft cover is smaller than that of the material of the first protrusion.

8. The developing cartridge as described in claim 1, characterized in that, The housing has a base wall and a retaining wall, the base wall extending in a direction intersecting the axial direction, and the retaining wall projecting from the base wall toward one side of the axial direction. The first protrusion protrudes from the retaining wall. The retaining wall has a first surface where the first protrusion is located and a second surface on the side opposite to the first surface. The housing has ribs that connect the base wall and the second surface of the retaining wall.

9. The developing cartridge as described in claim 8, characterized in that, The housing has a boss that protrudes from the base wall in one direction along the axial direction and is connected to the rib. The shaft cover has a second hole for the boss to be inserted.

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