JP2022092049A - Developer cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for positioning a developing roller of a developer cartridge, without using a shaft of the developing roller.

SOLUTION: The developer cartridge includes a housing for housing developer. The housing has one end and the other end in a first direction. The housing has a rotation shaft section 53. The housing can rotate around the rotation shaft section 53. The developer cartridge includes a first curved surface 631. The first curved surface 631 is located farther from an agitator shaft than a developing roller in the first direction. The first curved surface 631 can rotate together with the housing. Accordingly, the developing roller 30 can be positioned by using the rotation shaft section 53 different from the developing roller 30 and the first curved surface 631, without using a shaft of the developing roller 30.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present disclosure relates to a developing cartridge.

Conventionally, electrophotographic image forming devices such as laser printers and LED printers are known. A developing cartridge is used in the image forming apparatus. The developing cartridge has a developing roller. The conventional development cartridge is described in, for example, Patent Document 1. The developing cartridge of Patent Document 1 is mounted on a drum unit (process frame). The drum unit has a photosensitive drum. When the developing cartridge is inserted into the drum unit, the photosensitive drum and the developing roller face each other. Then, the drum unit to which the developing cartridge is mounted is housed inside the image forming apparatus.

Japanese Unexamined Patent Publication No. 2011-59510

When the developing cartridge is mounted on the drum unit, the developing cartridge is positioned on the frame of the drum unit by the shaft of the developing roller. As a result, the developing roller is positioned with respect to the photosensitive drum.

An object of the present invention is to provide a structure in a developing cartridge capable of positioning a developing roller without using a shaft of the developing roller.

In order to solve the above problems, the first invention of the present application is a housing capable of accommodating a developer, which has one end and the other end in the first direction, and extends in the second direction. An agitator having a moving shaft portion and rotatable in a rotational direction about the rotating shaft portion, and an agitator capable of stirring the developer and having an agitator shaft extending in the second direction. A developing roller located closer to one end of the agitator shaft in the first direction, rotatable about a rotating shaft extending in the second direction, and rotatable together with the housing. It is a first curved surface that curves in the rotation direction, is located away from the agitator shaft in the first direction from the developing roller, and can rotate in the rotation direction together with the housing. It is characterized by having a first curved surface.

The second invention of the present application is the developing cartridge of the first invention, characterized in that the distance between the developing roller and the first curved surface in the first direction is a constant distance.

The third invention of the present application is the developing cartridge of the first invention or the second invention, wherein the diameter of the first curved surface is smaller than the diameter of the outer peripheral surface of the developing roller.

The fourth invention of the present application is the developing cartridge of any one of the first to third inventions, wherein the housing includes the first curved surface.

The fifth invention of the present application is the developing cartridge of any one of the first to fourth inventions, which is rotatable about a rotation axis extending in the second direction, and is more than the developing roller in the first direction. A first roller located away from the agitator shaft, which is rotatable in the rotational direction together with the housing, and further includes a first roller having the first curved surface.

The sixth invention of the present application is the developing cartridge of the fifth invention, characterized in that the distance between the developing roller and the first roller in the first direction is a constant distance.

The seventh invention of the present application is the developing cartridge of the fifth invention or the sixth invention, characterized in that the diameter of the outer peripheral surface of the first roller is smaller than the diameter of the outer peripheral surface of the developing roller.

The eighth invention of the present application is the developing cartridge of any one of the fifth to seventh inventions, wherein the housing includes the shaft of the first roller.

The ninth invention of the present application is the developing cartridge of any one of the first to eighth inventions, and the developing cartridge is mounted on a drum unit having a photosensitive drum rotatable about a rotating shaft extending in the second direction. It is possible, and in a state where the developing cartridge is mounted on the drum unit, the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum, and when the developing cartridge is mounted on the drum unit, the first The curved surface is in contact with the outer peripheral surface of the photosensitive drum.

The tenth aspect of the present invention is the developing cartridge of the ninth invention, in which the developing cartridge is mounted on the drum unit, the housing, the developing roller, and the first curved surface are attached to the drum unit. Is characterized in that the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum, and the first curved surface comes into contact with the outer peripheral surface of the photosensitive drum.

The eleventh invention of the present application is the developing cartridge of the tenth invention, in which the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum after the first curved surface comes into contact with the outer peripheral surface of the photosensitive drum. It is characterized by doing.

The twelfth invention of the present invention is the developing cartridge of the first invention, which is a second curved surface curved in the rotation direction, and is separated from the agitator shaft by the developing roller in the first direction. It is a second curved surface that is located and is rotatable in the rotational direction together with the housing, and is further provided with a second curved surface that is located away from the first curved surface in the second direction. ..

The thirteenth invention of the present application is the developing cartridge of the twelfth invention, in which the distance between the developing roller and the first curved surface in the first direction is a constant distance, and the developing roller and the developing roller in the first direction are described. The distance from the second curved surface is a constant distance.

The 14th invention of the present application is the developing cartridge of the 12th invention or the 13th invention, in which the diameter of the first curved surface is smaller than the diameter of the outer peripheral surface of the developing roller, and the diameter of the second curved surface is It is characterized in that it is smaller than the diameter of the outer peripheral surface of the developing roller.

The fifteenth invention of the present application is a developing cartridge according to any one of the twelfth to fourteenth inventions, wherein the housing includes the first curved surface and the second curved surface. ..

The 16th invention of the present application is a development cartridge according to any one of the 12th to 15th inventions, which is rotatable about a rotation axis extending in the second direction and is more rotatable than the development roller in the first direction. A first roller located away from the agitator shaft, which is rotatable in the rotation direction together with the housing and has the first curved surface, and a rotation shaft extending in the second direction. A second roller that is rotatable in the first direction and is located farther from the agitator shaft than the developing roller, is rotatable in the rotational direction together with the housing, and is curved in the second direction. It is characterized by further comprising a second roller having a surface.

The 17th invention of the present application is the developing cartridge of the 16th invention, in which the distance between the developing roller and the first roller in the first direction is a constant distance, and the developing roller and the first roller in the first direction. The distance from the two rollers is a constant distance.

The eighteenth invention of the present application is the development cartridge of the sixteenth invention or the seventeenth invention, in which the diameter of the outer peripheral surface of the first roller is smaller than the diameter of the outer peripheral surface of the developing roller, and the outer circumference of the first roller is smaller. The surface diameter is smaller than the diameter of the outer peripheral surface of the developing roller.

The 19th invention of the present application is a developing cartridge according to any one of the 16th to 18th inventions, wherein the housing includes a shaft of the first roller and a shaft of the second roller. And.

The twentieth invention of the present application is a developing cartridge according to any one of the twelfth to nineteenth inventions, and the developing cartridge is mounted on a drum unit having a photosensitive drum rotatable about a rotating shaft extending in the second direction. It is possible, and in a state where the developing cartridge is mounted on the drum unit, the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum, and when the developing cartridge is mounted on the drum unit, the first The curved surface and the second curved surface are in contact with the outer peripheral surface of the photosensitive drum.

The 21st invention of the present application is the developing cartridge of the 20th invention, in which the developing cartridge is mounted on the drum unit, the housing, the developing roller, and the first curved surface are attached to the drum unit. After the second curved surface rotates in the rotation direction, the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum, and the first curved surface and the second curved surface are exposed to light. It is characterized in that it comes into contact with the outer peripheral surface of the drum.

The 22nd invention of the present application is the developing cartridge of the 21st invention, in which the outer peripheral surface of the developing roller becomes the outer peripheral surface of the developing roller after the first curved surface and the second curved surface come into contact with the outer peripheral surface of the photosensitive drum. It is characterized in that it comes into contact with the outer peripheral surface of the photosensitive drum.

The 23rd invention of the present application is a developing cartridge according to any one of the 1st to 22nd inventions, wherein the rotating shaft portion extends from the outer surface of the housing in the second direction. It is characterized by.

The 24th invention of the present application is a developing cartridge according to any one of the first to the 23rd inventions, and is a pressing receiving surface located closer to the other end portion than the rotating shaft portion in the first direction. The present invention is further provided with a pressing receiving surface that receives the pressing force.

The 25th invention of the present application is the developing cartridge of the 24th invention, wherein the pressing receiving surface receives the pressing force along the rotation direction.

The 26th invention of the present application is a developing cartridge according to any one of the ninth to eleventh inventions or the twenty to twenty-second inventions, wherein the developing roller is along the rotation axis. It has a developing roller shaft extending in the second direction, and the developing roller shaft and the drum unit are not in contact with each other.

The 27th invention of the present application is a developing cartridge according to any one of the first to 26th inventions, and the housing is rotated in the rotation direction about the rotation shaft portion in response to an external force. It is characterized by being movable.

According to the first to 27th inventions of the present application, the developing roller can be positioned by using a rotating shaft portion and a first curved surface different from the developing roller instead of the shaft of the developing roller.

Further, according to the twelfth invention to the twenty-second invention, the developing roller can be positioned by using the first curved surface and the second curved surface separated from the first curved surface in the second direction. As a result, the developing roller can be positioned more accurately.

First Embodiment: It is a perspective view of a developing cartridge and a drum unit. First Embodiment: It is a partially disassembled perspective view of a developing cartridge. First Embodiment: It is a figure which showed the state when the development cartridge is attached. First Embodiment: It is a figure which showed the state when the development cartridge is attached. First Embodiment: It is a figure which showed the state when the development cartridge is attached. Second Embodiment: It is an exploded perspective view of a developing cartridge.

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

Hereinafter, the direction in which the agitator and the developing roller are lined up is referred to as a "first direction". Further, the direction in which the rotation axis of the developing roller extends is referred to as a "second direction". The first direction and the second direction intersect each other (preferably orthogonally). The structure of the drum unit will also be described with reference to the "first direction" and "second direction" in the state where the developing cartridge is mounted on the drum unit.

<1. First Embodiment>
<1-1. Structure of developing cartridge and drum unit>
FIG. 1 is a perspective view of the developing cartridge 1 and the drum unit 9 of the first embodiment. The developing cartridge 1 and the drum unit 9 are used in an electrophotographic image forming apparatus. Examples of the image forming apparatus include a laser printer and an LED printer. The drum unit 9 is removable from the image forming apparatus. That is, the drum unit 9 is a replaceable cartridge. As shown in FIG. 1, the frame 90 of the drum unit 9 has four cartridge holding portions 91. Further, the drum unit 9 has a photosensitive drum 92 for each cartridge holding portion 91. Each photosensitive drum 92 is rotatable about a rotation axis extending in the second direction. Further, each photosensitive drum 92 has a cylindrical outer peripheral surface centered on the axis of rotation.

The developing cartridge 1 is removable from the cartridge holding portion 91. In this embodiment, four developing cartridges 1 are mounted on one drum unit 9. The four developing cartridges 1 contain developers of different colors (eg, cyan, magenta, yellow, and black). However, the number of developing cartridges 1 mounted on the drum unit 9 may be 1 to 3, or 5 or more.

FIG. 2 is a partially disassembled perspective view of the developing cartridge 1. As shown in FIGS. 1 and 2, the developing cartridge 1 has a casing 10, an agitator 20, a developing roller 30, a gear portion 40, a gear cover 50, and a bearing plate 60.

The casing 10 is a casing that can accommodate the developer. The casing 10 has a first outer surface 11 and a second outer surface 12. The first outer surface 11 is located at one end of the casing 10 in the second direction. The second outer surface 12 is located at the other end of the casing 10 in the second direction. The casing 10 extends in a second direction between the first outer surface 11 and the second outer surface 12. The gear portion 40, the gear cover 50, and the bearing plate 60 are located on the first outer surface 11. Further, a storage chamber 13 is provided inside the casing 10. The developer is housed in the storage chamber 13.

Further, the casing 10 has one end portion 15 and the other end portion 16 in the first direction. An opening 14 is provided in the vicinity of one end portion 15 of the casing 10. The containment chamber 13 and the outside communicate with each other through the opening 14.

The agitator 20 has an agitator shaft 21 and a stirring blade 22. The agitator shaft 21 is rotatable about a rotation axis extending in the second direction. The stirring blade 22 extends radially outward from the agitator shaft 21. At least a part of the agitator shaft 21 and the stirring blade 22 are located in the accommodating chamber 13. One end of the agitator shaft 21 in the second direction is fixed to the agitator gear 42 included in the gear portion 40 so as to be non-rotatable relative to the agitator gear 42. Therefore, the agitator shaft 21 and the stirring blade 22 rotate together with the agitator gear 42. When the stirring blade 22 rotates, the developer in the storage chamber 13 is stirred.

The developing roller 30 is a roller that can rotate about a rotation axis extending in the second direction. The developing roller 30 is located at the opening 14 of the casing 10. That is, the developing roller 30 is located closer to one end 15 than the agitator shaft 21 in the first direction. When the developing cartridge 1 is mounted on the cartridge holding portion 91 of the drum unit 9, the outer peripheral surface of the developing roller 30 comes into contact with the outer peripheral surface of the photosensitive drum 92.

The developing roller 30 of the present embodiment has a developing roller main body 31 and a developing roller shaft 32. The developing roller body 31 is a cylindrical member extending in the second direction. For example, elastic rubber is used as the material of the developing roller main body 31. The developing roller shaft 32 is a columnar member that penetrates the developing roller main body 31 in the second direction. As the material of the developing roller shaft 32, a metal or a resin having conductivity is used. The developing roller body 31 is fixed to the developing roller shaft 32 so as to be non-rotatable relative to the developing roller shaft 32.

The developing roller gear 43 included in the gear portion 40 is mounted on one end of the developing roller shaft 32 in the second direction. More specifically, one end of the developing roller shaft 32 in the second direction is fixed to the developing roller gear 43 so as to be non-rotatable relative to the developing roller gear 43. Therefore, when the developing roller gear 43 rotates, the developing roller shaft 32 also rotates, and the developing roller main body 31 also rotates together with the developing roller shaft 32.

The developing roller shaft 32 does not have to penetrate the developing roller main body 31 in the second direction. For example, the pair of developing roller shafts 32 may extend in the first direction from both ends of the developing roller main body 31 in the second direction. Specifically, the developing roller shaft 32 may be adhered or welded to both ends of the developing roller main body 31 in the second direction as separate parts.

Further, the developing cartridge 1 has a supply roller (not shown). The supply roller is located between the developing roller 30 and the agitator 20. Further, the supply roller is rotatable about a rotation axis extending in the second direction. When the developing cartridge 1 receives the driving force, the developing agent is supplied from the accommodation chamber 13 in the casing 10 to the outer peripheral surface of the developing roller 30 via the supply roller. At that time, the developer is triboelectrically charged between the supply roller and the developing roller 30. On the other hand, a bias voltage is applied to the developing roller shaft 32 of the developing roller 30. Therefore, the developing agent is attracted to the outer peripheral surface of the developing roller main body 31 by the electrostatic force between the developing roller shaft 32 and the developing agent.

Further, the developing cartridge 1 has a layer thickness regulating blade (not shown). The layer thickness regulating blade forms the developer supplied to the outer peripheral surface of the developing roller main body 31 to a constant thickness. After that, the developer on the outer peripheral surface of the developing roller body 31 is supplied to the photosensitive drum 92 of the drum unit 9. At this time, the developer moves from the developing roller main body 31 to the photosensitive drum 92 according to the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 92. As a result, an electrostatic latent image is visualized on the outer peripheral surface of the photosensitive drum 92.

The gear portion 40 is located on the first outer surface 11 of the casing 10. The gear portion 40 has a plurality of gears including the agitator gear 42 and the developing roller gear 43 described above, and a coupling 41. The coupling 41 has a fastening hole 411. When the drum unit 9 to which the developing cartridge 1 is mounted is housed in the image forming apparatus, the drive shaft of the image forming apparatus is inserted into the fastening hole 411 of the coupling 41. Then, the rotation of the drive shaft is transmitted to a plurality of gears including the agitator gear 42 and the developing roller gear 43 via the coupling 41.

In FIG. 2, the illustration of the teeth of each gear included in the gear portion 40 is omitted. The plurality of gears included in the gear portion 40 may transmit the rotational force by the meshing of the teeth, or may transmit the rotational force by friction. For example, the plurality of gears may have a rubber outer peripheral surface instead of teeth.

The gear cover 50 is fixed to the first outer surface 11 of the casing 10, for example, by screwing. The gear cover 50, together with the casing 10 and the bearing plate 60, constitutes a part of the housing of the developing cartridge 1. At least a part of the plurality of gears of the gear portion 40 is covered with the gear cover 50. The outer surface of the gear cover 50 has an extension 51 extending in the second direction. A circular hole 52 is provided at the tip of the extending portion 51. The coupling 41 fits into the circular hole 52. Therefore, the fastening hole 411 of the coupling 41 is exposed to the outside from the gear cover 50.

Further, the extending portion 51 of the gear cover 50 has a first rotating shaft portion 53. The first rotation shaft portion 53 projects from the surface of the extension portion 51 in a third direction intersecting (preferably orthogonal to) the first direction and the second direction, and extends in the second direction. Further, the casing 10 has a second rotation shaft portion 17 at the other end portion in the second direction. The second rotation shaft portion 17 projects from the surface of the casing 10 in the third direction and extends in the second direction. At least a part of the first rotation shaft portion 53 and at least a part of the second rotation shaft portion 17 are in overlapping positions when viewed in the second direction.

When the developing cartridge 1 is mounted on the cartridge holding portion 91 of the drum unit 9, the first rotating shaft portion 53 and the second rotating shaft portion 17 come into contact with the frame 90 of the drum unit 9. Then, the casing 10, the agitator 20, the developing roller 30, the gear portion 40, the gear cover 50, and the bearing plate 60 rotate first according to the external force received from the first pressing portion 95 and the second pressing portion 96, which will be described later. It rotates around the shaft portion 53 and the second rotating shaft portion 17.

The bearing plate 60 is located between the casing 10 and the gear cover 50 in the second direction. The bearing plate 60, together with the casing 10 and the gear cover 50, constitutes a part of the housing of the developing cartridge 1. The coupling 41 and the developing roller gear 43 described above are located between the bearing plate 60 and the gear cover 50. The agitator gear 42 described above is located between the casing 10 and the bearing plate 60. The bearing plate 60 has a flat plate portion 61 and a bearing protrusion 62. The flat plate portion 61 extends perpendicular to the second direction. The bearing protrusion 62 projects in the second direction from the flat plate portion 61 toward the gear cover 50. The coupling 41 rotates while being supported by the bearing projection 62.

The flat plate portion 61 of the bearing plate 60 has a first curved surface 63. The first curved surface 63 is located at one end of the bearing plate 60 in the first direction. Further, the first curved surface 63 is located farther from the agitator shaft 21 than the developing roller 30 in the first direction. The first curved surface 63 is rotatable about the first rotating shaft portion 53 and the second rotating shaft portion 17 described above together with other portions of the bearing plate 60. The first curved surface 63 projects in the direction of rotation about the first rotation shaft portion 53 and the second rotation shaft portion 17. Further, the first curved surface 63 is curved in an arc shape about an axis extending in the second direction.

Further, the casing 10 has a second curved surface 18 at the other end in the second direction. The second curved surface 18 is located at one end of the second outer surface 12 of the casing 10 in the first direction. Further, the second curved surface 18 is located farther from the agitator shaft 21 than the developing roller 30 in the first direction. The second curved surface 18 is rotatable about the first rotating shaft portion 53 and the second rotating shaft portion 17 described above together with the other portions of the casing 10. The second curved surface 18 projects in the rotation direction centered on the first rotation shaft portion 53 and the second rotation shaft portion 17. Further, the second curved surface 18 is curved in an arc shape about an axis extending in the second direction.

The first curved surface 63 and the second curved surface 18 are located apart from each other in the second direction. However, at least a part of the first curved surface 63 and at least a part of the second curved surface 18 are in overlapping positions when viewed in the second direction. Further, the first curved surface 63 and the second curved surface 18 have the same diameter. The diameters of the first curved surface 63 and the second curved surface 18 are smaller than the diameter of the outer peripheral surface of the developing roller 30. Further, the distance between the developing roller 30 and the first curved surface 63 in the first direction is a constant distance. Further, the distance between the developing roller 30 and the second curved surface 18 in the first direction is also a constant distance.

<1-2. Installation operation of the developing cartridge on the drum unit>
Subsequently, the operation when the developing cartridge 1 is attached to the cartridge holding portion 91 of the drum unit 9 will be described.

As shown in FIG. 1, the frame 90 of the drum unit 9 has a first contact surface 93 and a second contact surface 94 for each cartridge holding portion 91. The first contacted surface 93 is located at one end of the cartridge holding portion 91 in the second direction. The first contacted surface 93 is a surface that intersects (preferably orthogonally) with respect to the third direction and extends in the second direction. The second contacted surface 94 is located at the other end of the cartridge holding portion 91 in the second direction. The second contacted surface 94 is a surface that intersects (preferably orthogonally) with respect to the third direction and extends in the first direction.

As shown in FIG. 1, the frame 90 of the drum unit 9 has a first pressing portion 95 and a second pressing portion 96 for each cartridge holding portion 91. The first pressing portion 95 is located at one end of the cartridge holding portion 91 in the second direction. The first contact surface 93 and the first pressing portion 95 face each other in the third direction. The second pressing portion 96 is located at the other end of the cartridge holding portion 91 in the second direction. The second contact surface 94 and the second pressing portion 96 face each other in the third direction.

3 to 5 are views showing a state when the developing cartridge 1 is attached to the cartridge holding portion 91. As shown in FIGS. 3 to 5, the first pressing portion 95 includes a coil spring 951 and a pressing member 952. The coil spring 951 is an elastic member that can expand and contract in the third direction. One end of the coil spring 951 in the third direction is connected to the pressing member 952. The other end of the coil spring 951 in the third direction is connected to the frame 90 of the drum unit 9. The coil spring 951 is compressed in the third direction with respect to the natural length. Further, the coil spring 95 expands and contracts in the third direction between the first length and the second length shorter than the first length. When the coil spring 951 has the first length, the pressing member 952 is arranged in the first position. When the coil spring 951 has a second length, the pressing member 952 is arranged at a second position farther from the first contact surface 93 than at the first position. The pressing member 952 has a pressing surface 953 that projects in a third direction toward the first contact surface 93.

The second pressing portion 96 also has a coil spring and a pressing member, similarly to the first pressing portion 95.

When the developing cartridge 1 is inserted into the cartridge holding portion 91, first, the first rotating shaft portion 53 of the gear cover 50 comes into contact with the first contacted surface 93 of the frame 90, as shown in FIG. Similarly, the second rotating shaft portion 17 of the casing 10 comes into contact with the second contacted surface 94 of the frame 90.

Subsequently, of the outer surface of the extending portion 51 of the gear cover 50, the surface (hereinafter referred to as "first pressing receiving surface") 54 opposite to the first rotating shaft portion 53 in the third direction is the first. 1 Contact the pressing portion 95. Specifically, the first pressing receiving surface 54 comes into contact with the pressing surface 953. As a result, the length of the coil spring 951 contracts from the first length to the second length. Then, the first pressing receiving surface 54 receives the pressing force in the third direction from the first pressing portion 95. Further, also at the other end portion of the casing 10 in the second direction, the surface (hereinafter referred to as “second pressing receiving surface”) 19 opposite to the second rotating shaft portion 17 in the third direction is the second. Contact the pressing portion 96. As a result, the second pressing receiving surface 19 receives the pressing force in the third direction from the second pressing portion 96.

The first pressing receiving surface 54 is located closer to the other end portion 16 than the first rotating shaft portion 53 in the first direction. That is, the first pressing receiving surface 54 is located at a position farther from the developing roller 30 than the first rotating shaft portion 53 in the first direction. Further, the second pressing receiving surface 19 is located closer to the other end portion than the second rotating shaft portion 17 in the first direction. That is, the second pressing receiving surface 19 is located at a position farther from the developing roller 30 than the second rotating shaft portion 17 in the first direction.

The pressing force received by the first pressing receiving surface 54 and the second pressing receiving surface 19 has a component of force along the rotation direction about the first rotating shaft portion 53 and the second rotating shaft portion 17. .. Therefore, due to the pressing force received by the first pressing receiving surface 54 and the second pressing receiving surface 19, the developing cartridge 1 is centered on the first rotating shaft portion 53 and the second rotating shaft portion 17, and is shown in FIG. Rotate in the direction of the dashed arrow. Therefore, the developing roller 30, the first curved surface 63, and the second curved surface 18 also rotate around the first rotation shaft portion 53 and the second rotation shaft portion. As a result, the developing roller 30, the first curved surface 63, and the second curved surface 18 approach the photosensitive drum 92. Then, first, as shown in FIG. 4, the first curved surface 63 and the second curved surface 18 come into contact with the outer peripheral surface of the photosensitive drum 92. After that, as shown in FIG. 5, the outer peripheral surface of the developing roller 30 comes into contact with the outer peripheral surface of the photosensitive drum 92. As a result, the position and orientation of the developing cartridge 1 with respect to the photosensitive drum 92 are fixed. Then, the outer peripheral surface of the photosensitive drum 92 and the outer peripheral surface of the developing roller 30 are maintained in contact with each other.

As described above, the developing cartridge 1 of the present embodiment is not positioned on the frame 90 of the drum unit 9 by using the developing roller shaft 32, but the first rotating shaft portion 53 and the second rotating shaft portion 53, which are different from the developing roller shaft 32. The developing roller 30 is positioned by using the rotating shaft portion 17, the first curved surface 63, and the second curved surface 18. The developing roller shaft 32 and the frame 90 of the drum unit 9 are not in contact with each other. That is, the developing roller shaft 32 and the frame 90 of the drum unit 9 are not in direct contact with each other, nor are they indirect contact with each other via other members. Therefore, the developing roller 30 can be positioned without depending on the dimensional accuracy of the developing roller shaft 32.

Conventionally, a large number of parts have been involved in the positioning of the developing roller with respect to the photosensitive drum. Specifically, the outer peripheral surface of the photosensitive drum, the bearing of the photosensitive drum provided on the frame of the drum unit, and the guide groove for the developing roller shaft provided on the frame were involved in the positioning of the developing roller with respect to the photosensitive drum. .. Further, the developing roller shaft, and in some cases, the collar attached to the developing roller shaft, the bearing of the developing roller, and the outer peripheral surface of the developing roller were also involved in the positioning of the developing roller with respect to the photosensitive drum. On the other hand, in the structure of the present embodiment, the surface of the photosensitive drum 92, the first curved surface 63 and the second curved surface 18 of the bearing plate 60, and the outer peripheral surface of the developing roller 30 form a developing roller for the photosensitive drum 92. 30 can be positioned. Therefore, the number of parts involved in positioning is reduced. As a result, positioning errors due to tolerances of each component can be suppressed.

Further, conventionally, the guide groove of the frame is provided along the direction in which the photosensitive drums are lined up. Therefore, in the conventional structure, it is necessary to widen the space between adjacent photosensitive drums. On the other hand, in the structure of the present embodiment, it is not necessary to provide the guide groove in the frame 90. Therefore, the distance between the adjacent photosensitive drums 92 can be made narrower than before.

As described above, in the first embodiment, after the first curved surface 63 and the second curved surface 18 come into contact with the outer peripheral surface of the photosensitive drum 92, the outer peripheral surface of the developing roller 30 is contacted with the outer peripheral surface of the photosensitive drum 92. Contact. In this case, when the developing cartridge 1 is mounted on the cartridge holding portion 91, the contact pressure between the first curved surface 63 and the second curved surface 18 with respect to the outer peripheral surface of the photosensitive drum 92 becomes large.

However, after the outer peripheral surface of the developing roller 30 comes into contact with the outer peripheral surface of the photosensitive drum 92, the first curved surface 63 and the second curved surface 18 may come into contact with the outer peripheral surface of the photosensitive drum 92. In this case, when the developing cartridge 1 is mounted on the cartridge holding portion 91, the contact pressure of the outer peripheral surface of the developing roller 30 with respect to the outer peripheral surface of the photosensitive drum 92 becomes large. When the developing cartridge 1 is removed from the cartridge holding portion 91, the contact pressure of the first curved surface 63 and the second curved surface 18 with respect to the outer peripheral surface of the photosensitive drum 92 may be temporarily increased.

Immediately after the developing cartridge 1 is inserted into the cartridge holding portion 91 of the drum unit 9, all of the developing roller 30, the first curved surface 63, and the second curved surface 18 come into contact with the outer peripheral surface of the photosensitive drum 92. You don't have to. After the drum unit is inserted into the image forming apparatus, the photosensitive drum 92 and the developing roller 30 start rotating due to the driving force from the image forming apparatus, whereby the developing roller 30, the first curved surface 63, and the second curved surface are started to rotate. All of 18 may be in contact with the outer peripheral surface of the photosensitive drum 92.

For example, after inserting the developing cartridge 1 into the cartridge holding portion 91 of the drum unit 9, the first curved surface 63 and the second curved surface 18 are in contact with the outer peripheral surface of the photosensitive drum 92, but the outer peripheral surface of the developing roller 30 When is not in contact with the outer peripheral surface of the photosensitive drum 92, the frictional force between the photosensitive drum 92 and the first curved surface 63 and the second curved surface 18 generated by the rotation of the photosensitive drum 92 causes the first curved surface 63 and The second curved surface 18 moves in the rotation direction of the photosensitive drum 92. As a result, the outer peripheral surface of the developing roller 30 may come into contact with the outer peripheral surface of the photosensitive drum 92.

Further, for example, after the developing cartridge 1 is inserted into the cartridge holding portion 91 of the drum unit 9, the outer peripheral surface of the developing roller 30 is in contact with the outer peripheral surface of the photosensitive drum 92, but the first curved surface 63 and the second curved surface 63. When the surface 18 is not in contact with the outer peripheral surface of the photosensitive drum 92, the rotation speed of the developing roller 30 is faster than the rotation speed of the photosensitive drum 92, so that the developing roller 30 moves on the outer peripheral surface of the photosensitive drum 92. .. As a result, the first curved surface 63 and the second curved surface 18 may come into contact with the outer peripheral surface of the photosensitive drum 92.

In the present embodiment, the bearing plate 60 forming a part of the housing of the developing cartridge 1 includes the first curved surface 63. Therefore, it is not necessary to provide a member having the first curved surface 63 separately from the bearing plate 60. As a result, the number of parts of the developing cartridge 1 can be suppressed. Further, in the present embodiment, the casing 10 forming a part of the housing of the developing cartridge 1 includes the second curved surface 18. Therefore, it is not necessary to provide a member having the second curved surface 18 separately from the casing 10. As a result, the number of parts of the developing cartridge 1 can be suppressed. However, the first curved surface 63 and the second curved surface 18 may be provided on a member different from the housing of the developing cartridge 1.

Further, in the present embodiment, the diameter of the first curved surface 63 is smaller than the diameter of the outer peripheral surface of the developing roller 30. Further, the diameter of the second curved surface 18 is smaller than the diameter of the outer peripheral surface of the developing roller 30. This facilitates mounting the developing cartridge 1 on the cartridge holding portion 91. Even when the drum unit is miniaturized, the diameter of the first curved surface 63 is smaller than the diameter of the outer peripheral surface of the developing roller 30, and the diameter of the second curved surface 18 is the diameter of the outer peripheral surface of the developing roller 30. Since it is smaller than the above, the developing cartridge 1 can be easily attached to the cartridge holding portion 91.

<2. 2nd Embodiment>
Subsequently, the developing cartridge 1 of the second embodiment will be described.

The developing cartridge 1 of the second embodiment is different from the first embodiment in that it has the first roller 71 and the second roller 72. Hereinafter, the differences from the first embodiment will be mainly described, and the same parts as those of the first embodiment are designated by the same reference numerals as those of the first embodiment, and duplicate description will be omitted.

FIG. 6 is an exploded perspective view of the developing cartridge 1 of the second embodiment. In FIG. 6, the gear cover 50 is not shown. As shown in FIG. 6, in the second embodiment, the casing 10 has a first roller shaft 711 and a second roller shaft 721. The first roller shaft 711 is located at one end of the first outer surface 11 of the casing 10 in the first direction. That is, the first roller shaft 711 is located farther from the agitator shaft 21 than the developing roller 30 in the first direction. Further, the first roller shaft 711 is cylindrical and extends in the second direction. The second roller shaft 721 is located at one end of the second outer surface 12 of the casing 10 in the first direction. That is, the second roller shaft 721 is located farther from the agitator shaft 21 than the developing roller 30 in the first direction. Further, the second roller shaft 721 is cylindrical and extends in the second direction.

The first roller 71 is a roller having a cylindrical outer peripheral surface (first curved surface). The second roller 72 is a roller having a cylindrical outer peripheral surface (second curved surface). The diameter of the outer peripheral surface of the first roller 71 and the second roller 72 is smaller than the diameter of the outer peripheral surface of the developing roller 30. The first roller 71 is supported by the first roller shaft 711 and is rotatable about a rotation shaft extending in the second direction. The second roller 72 is supported by the second roller shaft 721 and is rotatable about a rotation shaft extending in the second direction. The first roller 71 and the second roller 72 are located farther from the agitator shaft 21 than the developing roller 30 in the first direction. When the casing 10 rotates around the first rotation shaft portion 53 and the second rotation shaft portion 17, the first roller 71 and the second roller 72 also, together with the casing 10, the first rotation shaft portion 53 and the first rotation shaft portion 53 and the second roller 72. 2 Rotates around the rotating shaft portion 17.

The first roller 71 and the second roller 72 are located apart from each other in the second direction. However, at least a part of the first roller 71 and at least a part of the second roller 72 are in overlapping positions when viewed in the second direction. Further, the outer peripheral surface of the first roller 71 and the outer peripheral surface of the second roller 72 have the same diameter. The diameter of the outer peripheral surface of the first roller 71 and the second roller 72 is smaller than the diameter of the outer peripheral surface of the developing roller 30. Further, the distance between the developing roller 30 and the first roller 71 in the first direction is a constant distance. The distance between the developing roller 30 and the second roller 72 in the first direction is also a constant distance.

When the developing cartridge 1 of the second embodiment is mounted on the cartridge holding portion 91 of the drum unit 9, it is developed by the pressing pressure from the first pressing portion 95 and the second pressing portion 96, as in the first embodiment. The cartridge 1 rotates about the first rotation shaft portion 53 and the second rotation shaft portion 17. At this time, together with the casing 10, the developing roller 30, the first roller 71, and the second roller 72 also rotate around the first rotating shaft portion 53 and the second rotating shaft portion 17. As a result, the developing roller 30, the first roller 71, and the second roller 72 come into contact with the photosensitive drum 92. As a result, the position and orientation of the developing cartridge 1 with respect to the photosensitive drum 92 are fixed. Then, the outer peripheral surface of the photosensitive drum 92 and the outer peripheral surface of the developing roller 30 are maintained in contact with each other.

Further, the developing cartridge 1 includes a third roller 73 and a fourth roller 74. The third roller 73 is located at one end of the developing roller body 31 in the second direction. The third roller 73 is rotatably supported by one end of the developing roller shaft 32 in the second direction. Further, the fourth roller 74 is located at the other end of the developing roller main body 31 in the second direction. The fourth roller 74 is rotatably supported by the other end of the developing roller shaft 32 in the second direction. As a result, even when the outer peripheral surface of the developing roller body 31 is excessively pressed against the outer peripheral surface of the photosensitive drum 92, the third roller 73 and the fourth roller 74 come into contact with the surface of the photosensitive drum 92. Therefore, the pressing force of the developing roller main body 31 with respect to the outer peripheral surface of the photoconductor drum 92 can be appropriately adjusted.

As described above, also in this second embodiment, the development roller shaft 32 is not positioned on the frame 90 of the drum unit 9, but the first rotation shaft portion 53 and the second rotation different from the development roller shaft 32. The developing roller 30 is positioned by using the shaft portion 17, the first roller 71, and the second roller 72. The developing roller shaft 32 and the frame 90 of the drum unit 9 are not in contact with each other. That is, the developing roller shaft 32 and the frame 90 of the drum unit 9 are not in direct contact with each other, nor are they indirect contact with each other via other members. Therefore, the developing roller 30 can be positioned without depending on the dimensional accuracy of the developing roller shaft 32.

Also in this second embodiment, the positioning of the developing roller 30 with respect to the photosensitive drum 92 can be performed with a smaller number of parts than in the conventional case. Therefore, the positioning error due to the tolerance of each component can be suppressed.

In particular, in the present embodiment, the outer peripheral surface of the first roller 71, which is the first curved surface, can rotate about the first roller shaft 711. Further, the outer peripheral surface of the second roller 72, which is the second curved surface, can rotate around the second roller shaft 721. Therefore, when the first roller 71 and the second roller 72 come into contact with the photosensitive drum 92, between the outer peripheral surface of the first roller 71 or the outer peripheral surface of the second roller 72 and the outer peripheral surface of the photosensitive drum 92. , Rubbing is less likely to occur. In addition, scraping of the surface of the photosensitive drum 92 can be suppressed. Further, the rotational torque of the photosensitive drum 92 can be reduced.

Further, in the present embodiment, the first roller shaft 711 is included in the casing 10 that constitutes a part of the housing of the developing cartridge 1. Therefore, it is not necessary to provide a member having the first roller shaft 711 separately from the casing 10. As a result, the number of parts of the developing cartridge 1 can be suppressed. Further, in the present embodiment, the second roller shaft 721 is included in the casing 10 that constitutes a part of the housing of the developing cartridge 1. Therefore, it is not necessary to provide a member having the second roller shaft 721 separately from the casing 10. As a result, the number of parts of the developing cartridge 1 can be suppressed. However, the first roller shaft 711 and the second roller shaft 721 may be provided on a member different from the housing of the developing cartridge 1.

When the developing cartridge 1 of the second embodiment is mounted on the cartridge holding portion 91 of the drum unit 9, for example, the outer peripheral surface of the first roller 71 and the outer peripheral surface of the second roller 72 come into contact with the outer peripheral surface of the photosensitive drum 92. After that, the outer peripheral surface of the developing roller 30 comes into contact with the outer peripheral surface of the photosensitive drum 92. In this case, when the developing cartridge 1 is mounted on the cartridge holding portion 91, the contact pressure between the outer peripheral surface of the first roller 71 and the outer peripheral surface of the second roller 72 with respect to the outer peripheral surface of the photosensitive drum 92 increases.

However, after the outer peripheral surface of the developing roller 30 comes into contact with the outer peripheral surface of the photosensitive drum 92, the outer peripheral surface of the first roller 71 and the outer peripheral surface of the second roller 72 may come into contact with the outer peripheral surface of the photosensitive drum 92. .. In this case, when the developing cartridge 1 is mounted on the cartridge holding portion 91, the contact pressure on the outer peripheral surface of the developing roller 30 with respect to the outer peripheral surface of the photosensitive drum 92 increases. Even if the contact pressure between the outer peripheral surface of the first roller 71 and the outer peripheral surface of the second roller 72 with respect to the outer peripheral surface of the photosensitive drum 92 temporarily increases when the developing cartridge 1 is removed from the cartridge holding portion 91. good.

Immediately after inserting the developing cartridge 1 into the cartridge holding portion 91 of the drum unit 9, all of the developing roller 30, the first roller 71, and the second roller 72 are in contact with the outer peripheral surface of the photosensitive drum 92. It does not have to be. After the drum unit is inserted into the image forming apparatus, the photosensitive drum 92 and the developing roller 30 start rotating due to the driving force from the image forming apparatus, so that the outer peripheral surface of the developing roller 30 and the outer peripheral surface of the first roller 71. All of the outer peripheral surface of the second roller 72 may be in contact with the outer peripheral surface of the photosensitive drum 92.

Further, in the present embodiment, the diameter of the outer peripheral surface of the first roller 71 is smaller than the diameter of the outer peripheral surface of the developing roller 30. Further, the diameter of the outer peripheral surface of the second roller 72 is smaller than the diameter of the outer peripheral surface of the developing roller 30. This facilitates mounting the developing cartridge 1 on the cartridge holding portion 91. Further, even when the drum unit is miniaturized, the diameter of the outer peripheral surface of the first roller 71 is smaller than the diameter of the outer peripheral surface of the developing roller 30, and the diameter of the outer peripheral surface of the second roller 72 is the diameter of the developing roller 30. Since it is smaller than the diameter of the outer peripheral surface, it is easy to mount the developing cartridge 1 on the cartridge holding portion 91.

Instead of the casing 10 having the first roller shaft 711, the first roller 71 may have the first roller shaft. In this case, the casing 10 may have an opening into which the first roller shaft can be inserted. Further, instead of the casing 10 having the second roller shaft, the second roller may have the second roller shaft. In this case, the casing 10 may have an opening into which the second roller shaft can be inserted.

<3. Modification example>
Although the first embodiment and the second embodiment have been described above, the present invention is not limited to the above embodiment.

In the above embodiment, the developing cartridge has a first rotation shaft portion and a second rotation shaft portion. However, the number of rotating shaft portions included in the developing cartridge may be one or three or more. For example, the developing cartridge may have one rotating shaft portion extending from one end to the other end in the second direction. Further, in the above embodiment, the developing cartridge has a first curved surface and a second curved surface. However, the number of curved surfaces of the developing cartridge may be one or three or more. For example, the developing cartridge may have one curved surface extending from one end to the other end in the second direction.

Further, in the above embodiment, the shape of the curved surface is an arc shape. However, the curved surface may be a convex curved surface and may not necessarily have an arc shape. The shape of the curved surface may be spherical, for example.

Further, in the above embodiment, the frame 90 of the drum unit 9 has a first pressing portion 95 and a second pressing portion 96 for each cartridge holding portion 91. However, instead of the frame 90 having a first pressing portion 95 and a second pressing portion 96, the developing cartridge 1 may have a first pressing portion and a second pressing portion. In this case, the first pressing portion 95 and the second pressing portion 96 come into contact with the frame 90, and the developing cartridge 1 rotates with respect to the frame 90 in response to the pressing force.

Further, the shape of each part of the developing cartridge may be different from the shape shown in each figure of the present application. In addition, the elements appearing in the first embodiment, the second embodiment, and the modified examples may be appropriately combined as long as there is no contradiction.

1 Development cartridge 9 Drum unit 10 Casing 11 First outer surface 12 Second outer surface 13 Storage chamber 14 Opening 15 One end 16 The other end 17 Second rotation shaft 18 Second curved surface 19 Second pressing receiving surface 20 Agitator 21 Agitator shaft 22 Stirring blade 30 Development roller 31 Development roller body 32 Development roller shaft 40 Gear part 41 Coupling 42 Agitator gear 43 Development roller gear 50 Gear cover 51 Extension part 52 Circular hole 53 First rotation shaft part 54 First pressing Receiving surface 60 Bearing plate 61 Flat plate 62 Bearing protrusion 63 1st curved surface 71 1st roller 72 2nd roller 73 3rd roller 74 4th roller 90 Frame 91 Cartridge holder 92 Photosensitive drum 93 1st contact surface 94 2nd Contacted surface 95 1st pressing part 96 2nd pressing part 411 Fastening hole 711 1st roller shaft 721 2nd roller shaft 951 Coil spring 952 Pressing member 953 Pressing surface

Claims (27)

A housing capable of accommodating a developing agent, which has one end and the other end in the first direction, has a rotation shaft portion extending in the second direction, and is centered on the rotation shaft portion. With a housing that can rotate in the direction of rotation,
An agitator capable of stirring the developer, the agitator having the agitator shaft extending in the second direction, and the agitator.
A developing roller located closer to one end of the agitator shaft in the first direction, rotatable about a rotating shaft extending in the second direction, and rotatable together with the housing.
A first curved surface that curves in the direction of rotation, is located in the first direction away from the agitator shaft from the developing roller, and is rotatable in the direction of rotation together with the housing. 1 curved surface and
A developing cartridge characterized by being equipped with. The developing cartridge according to claim 1.
A developing cartridge characterized in that the distance between the developing roller and the first curved surface in the first direction is a constant distance. The developing cartridge according to claim 1 or 2.
A developing cartridge characterized in that the diameter of the first curved surface is smaller than the diameter of the outer peripheral surface of the developing roller. The developing cartridge according to any one of claims 1 to 3.
The housing is a developing cartridge including the first curved surface. The developing cartridge according to any one of claims 1 to 4.
A first roller that is rotatable about a rotation axis extending in the second direction and is located farther from the agitator shaft than the developing roller in the first direction, and rotates in the rotation direction together with the housing. A developing cartridge that is possible and further comprises a first roller having the first curved surface. The developing cartridge according to claim 5.
A developing cartridge characterized in that the distance between the developing roller and the first roller in the first direction is a constant distance. The developing cartridge according to claim 5 or 6.
A developing cartridge characterized in that the diameter of the outer peripheral surface of the first roller is smaller than the diameter of the outer peripheral surface of the developing roller. The developing cartridge according to any one of claims 5 to 7.
The housing is a developing cartridge including the shaft of the first roller. The developing cartridge according to any one of claims 1 to 8.
The developing cartridge can be mounted on a drum unit having a photosensitive drum that is rotatable about a rotation axis extending in the second direction.
With the developing cartridge mounted on the drum unit, the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum.
A developing cartridge characterized in that the first curved surface comes into contact with the outer peripheral surface of the photosensitive drum when the developing cartridge is mounted on the drum unit. The developing cartridge according to claim 9.
In a state where the developing cartridge is mounted on the drum unit, after the housing, the developing roller, and the first curved surface rotate in the rotational direction with respect to the drum unit, the outer peripheral surface of the developing roller. Is in contact with the outer peripheral surface of the photosensitive drum, and the first curved surface is in contact with the outer peripheral surface of the photosensitive drum. The developing cartridge according to claim 10.
A developing cartridge characterized in that the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum after the first curved surface comes into contact with the outer peripheral surface of the photosensitive drum. The developing cartridge according to claim 1.
A second curved surface that curves in the direction of rotation, is located in the first direction away from the agitator shaft than the developing roller, and is rotatable in the direction of rotation together with the housing. A developing cartridge having two curved surfaces, further comprising a second curved surface located away from the first curved surface in the second direction. The developing cartridge according to claim 12.
The distance between the developing roller and the first curved surface in the first direction is a constant distance.
A developing cartridge characterized in that the distance between the developing roller and the second curved surface in the first direction is a constant distance. The developing cartridge according to claim 12 or 13.
The diameter of the first curved surface is smaller than the diameter of the outer peripheral surface of the developing roller.
A developing cartridge characterized in that the diameter of the second curved surface is smaller than the diameter of the outer peripheral surface of the developing roller. The developing cartridge according to any one of claims 12 to 14.
The housing is a developing cartridge including the first curved surface and the second curved surface. The developing cartridge according to any one of claims 12 to 15.
A first roller that is rotatable about a rotation axis extending in the second direction and is located farther from the agitator shaft than the developing roller in the first direction, and rotates in the rotation direction together with the housing. With the first roller having the first curved surface, which is possible,
A second roller that is rotatable about a rotation axis extending in the second direction and is located farther from the agitator shaft than the developing roller in the first direction, and rotates in the rotation direction together with the housing. A second roller having the second curved surface, which is possible,
A developing cartridge characterized by being further equipped with. The developing cartridge according to claim 16.
The distance between the developing roller and the first roller in the first direction is a constant distance.
A developing cartridge characterized in that the distance between the developing roller and the second roller in the first direction is a constant distance. The developing cartridge according to claim 16 or 17.
The diameter of the outer peripheral surface of the first roller is smaller than the diameter of the outer peripheral surface of the developing roller.
A developing cartridge characterized in that the diameter of the outer peripheral surface of the first roller is smaller than the diameter of the outer peripheral surface of the developing roller. The developing cartridge according to any one of claims 16 to 18.
The housing is a developing cartridge including a shaft of the first roller and a shaft of the second roller. The developing cartridge according to any one of claims 12 to 19.
The developing cartridge can be mounted on a drum unit having a photosensitive drum that is rotatable about a rotation axis extending in the second direction.
With the developing cartridge mounted on the drum unit, the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum.
A developing cartridge characterized in that the first curved surface and the second curved surface come into contact with the outer peripheral surface of the photosensitive drum when the developing cartridge is mounted on the drum unit. The developing cartridge according to claim 20.
In a state where the developing cartridge is mounted on the drum unit, after the housing, the developing roller, the first curved surface, and the second curved surface rotate in the rotational direction with respect to the drum unit. A developing cartridge characterized in that the outer peripheral surface of the developing roller is in contact with the outer peripheral surface of the photosensitive drum, and the first curved surface and the second curved surface are in contact with the outer peripheral surface of the photosensitive drum. The developing cartridge according to claim 21.
A developing cartridge characterized in that the outer peripheral surface of the developing roller comes into contact with the outer peripheral surface of the photosensitive drum after the first curved surface and the second curved surface come into contact with the outer peripheral surface of the photosensitive drum. The developing cartridge according to any one of claims 1 to 22.
The developing shaft portion extends from the outer surface of the housing in the second direction. The developing cartridge according to any one of claims 1 to 23.
A developing cartridge that is a pressing receiving surface located closer to the other end portion than the rotating shaft portion in the first direction, and further includes a pressing receiving surface that receives the pressing force. The developing cartridge according to claim 24.
The developing cartridge, wherein the pressing receiving surface receives the pressing force along the rotation direction. The developing cartridge according to any one of claims 9 to 11 or any one of claims 20 to 22.
The developing roller
It has a developing roller shaft that extends in the second direction along the axis of rotation.
A developing cartridge characterized in that the developing roller shaft and the drum unit are not in contact with each other. The developing cartridge according to any one of claims 1 to 26.
The developing cartridge is characterized in that the housing is rotatable in the rotation direction about the rotation shaft portion in response to an external force.

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