Developing cartridge

Abstract

A developing cartridge that is attachable to and detachable from a drum cartridge includes: a housing that accommodates toner; a developing roller rotatable about a developing axis extending in a first direction; an agitator rotatable about an agitator shaft extending in a first direction; a coupling gear on a first outer surface of the housing; the idle gear is positioned on the first outer surface and is meshed with the coupling gear; the stirrer gear is positioned on the first outer surface, is connected with the stirrer and is meshed with the idle gear; the detection gear is located on the first outer surface and meshed with the idle gear, and when the detection gear rotates, meshing of the detection gear and the idle gear is disengaged. The housing has a convex portion that receives a pressing force in the second direction from the drum box, and the convex portion extends in the first direction from the first outer surface toward an outer side of the housing, and the idle gear is located between the agitator gear and the convex portion. The developing box is provided with a convex part which receives pressing force from a drum box, and the external dimension of the developing box in the pressing direction can be restrained.

Description

Technical Field

[0001] This invention relates to a developing cartridge. Background Technology

[0002] Previously, image forming apparatuses using electrophotographic methods, such as laser printers and LED printers, were known. For example, a conventional image forming apparatus is described in Patent Document 1. The image forming apparatus of Patent Document 1 includes a developing cartridge and a drum cartridge (photosensitive cartridge). The developing cartridge is mounted on the drum cartridge. Furthermore, the drum cartridge, on which the developing cartridge is mounted, is mounted on the main frame of the image forming apparatus.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-016480

[0004] The developing cartridge has a developing roller. The drum cartridge has a photosensitive drum. When the developing cartridge is installed in the drum cartridge, the developing roller contacts the photosensitive drum. Additionally, the developing roller is pressed towards the photosensitive drum by pressure received from the drum cartridge.

[0005] However, as in Patent Document 1, in the case where the rear surface of the toner chamber is pressed by a pressing member, if the toner chamber is enlarged in order to further increase the toner capacity, the external dimensions of the developing cartridge in the pressing direction become larger. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a developing cartridge having a protrusion that receives pressure from the drum and is capable of suppressing the external dimensions of the developing cartridge in the pressing direction.

[0007] The first approach is characterized by a developing cartridge, detachable relative to a drum cartridge, comprising: a housing containing toner and having a first outer surface and a second outer surface extending away from the first outer surface in a first direction; a developing roller rotatable about a developing shaft extending along the first direction and located at one end of the housing in a second direction intersecting the first direction; a stirrer rotatable about a stirrer shaft extending along the first direction; a coupling gear located on the first outer surface; and an idle gear located on the first outer surface. The housing has a protrusion that receives pressure in the second direction from the drum and extends from the first outer surface toward the outside of the housing in the first direction. The idle gear is located between the agitator gear and the first outer surface, connected to the agitator and meshing with the idle gear. The housing has a protrusion that receives pressure in the second direction from the drum and extends from the first outer surface toward the outside of the housing in the first direction. The idle gear is located between the agitator gear and the protrusion.

[0008] The second method is characterized in that, in the developing cartridge of the first method, the protrusion has a rib that protrudes in the second direction toward the direction away from the developing roller, and the rib bears the pressing pressure in the second direction from the drum.

[0009] The third approach is characterized in that, in the developing cartridge of the first or second approach, at least a portion of the protrusion is located in the same position as the coupling gear, the idle gear, the agitator gear, or the detection gear in the first direction.

[0010] The fourth approach is characterized in that, in a third-party developing cartridge, at least a portion of the protrusion is located in the same position as the detection gear in the first direction.

[0011] The fifth method is characterized in that, in the developing cartridge of any of the first to fourth methods, the idle gear has: a large-diameter idle gear; and a small-diameter idle gear, the diameter of which is smaller than that of the large-diameter idle gear, the large-diameter idle gear meshing with the coupling gear, and the small-diameter idle gear meshing with the agitator gear and the detection gear.

[0012] The sixth method is characterized in that, in the developing cartridge of any of the first to fifth methods, the coupling gear has: a large-diameter coupling gear; and a small-diameter coupling gear, the diameter of which is smaller than that of the large-diameter coupling gear, and the small-diameter coupling gear meshes with the idle speed gear.

[0013] The seventh method is characterized in that, in the developing cartridge of any of the first to sixth methods, in the first direction, the detection gear is located further away from the first outer surface than the stirrer gear.

[0014] The eighth method is characterized in that, in any of the first to seventh methods, the developing cartridge also includes a developing roller gear, which is located on the first outer surface, connected to the developing roller, and meshes with the coupling gear.

[0015] The ninth method is characterized in that, in the developing chamber of the eighth method, the coupling gear has: a large-diameter coupling gear; and a small-diameter coupling gear, the diameter of which is smaller than the diameter of the large-diameter coupling gear, the large-diameter coupling gear meshing with the developing roller gear.

[0016] The tenth embodiment is characterized in that, in any of the first to ninth embodiments, the developing cartridge further comprises: a supply roller capable of rotating about a supply roller extending along the first direction and in contact with the developing roller; and a supply roller gear located on the first outer surface, connected to the supply roller, and meshing with the coupling gear.

[0017] The eleventh method is characterized in that, in the developing chamber of the tenth method, the coupling gear has: a large-diameter coupling gear; and a small-diameter coupling gear, the diameter of which is smaller than that of the large-diameter coupling gear, the small-diameter coupling gear meshing with the supply roller gear.

[0018] The twelfth embodiment is characterized in that, in any of the first to ninth embodiments, the developing cartridge further comprises: a supply roller rotatable about a supply shaft extending along the first direction and in contact with the developing roller; and a sponge located at one end of the supply roller in the first direction, the protrusion holding the sponge.

[0019] The thirteenth method is characterized in that, in any of the first to twelfth methods, the developing cartridge further includes a gear cover located on the first outer surface and housing the coupling gear, the idle gear, and the agitator gear inside, with a portion of the detection gear located inside the gear cover and the other portion of the detection gear exposed to the outside of the gear cover.

[0020] The fourteenth method is characterized in that, in the developing cartridge of the thirteenth method, the gear cover has an opening that is aligned with the protrusion along the second direction.

[0021] According to the first to fourteenth embodiments, the protrusion that receives pressing pressure from the drum is located on the outer side of the first outer surface of the housing in the first direction. This prevents the external dimensions of the housing in the second direction from increasing due to the protrusion.

[0022] Furthermore, according to the third method, compared to the case where the protrusion and the detection gear are positioned at different locations in the first direction, the length of the developing cartridge in the first direction can be reduced.

[0023] Furthermore, according to the fourth method, compared with the case where the protrusion and the detection gear are arranged at different positions in the first direction, the length of the developing cartridge in the first direction can be reduced.

[0024] Furthermore, according to the twelfth method, the housing can be miniaturized compared to the case where the protrusion and the cage are provided separately. Attached Figure Description

[0025] Figure 1 It is a 3D view of the developing chamber and drum unit.

[0026] Figure 2 It is a 3D view of the developing chamber and drum unit.

[0027] Figure 3 This is a 3D view of the developing chamber.

[0028] Figure 4 This is a diagram of the developing chamber with the gear cover removed, viewed along the first direction.

[0029] Figure 5 This is a partial 3D view of the developing chamber with the gear cover removed.

[0030] Figure 6 This is a view of the vicinity of the gear section of the developing cartridge from a direction intersecting the first and second directions.

[0031] Figure 7 This is a cross-sectional view of the developer cartridge and the drum cartridge with the developer cartridge installed in the drum cartridge.

[0032] Figure 8 This is a cross-sectional view of the developer cartridge and the drum cartridge with the developer cartridge installed in the drum cartridge. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0034] Furthermore, the direction in which the first outer surface 11 and the second outer surface 12 of the housing 10 of the developing cartridge 1 are arranged is referred to as the "first direction". Additionally, the direction in which one end of the housing 10 containing the developing roller 30 and the other end of the housing are arranged is referred to as the "second direction". The first direction and the second direction intersect each other. For example, the first direction and the second direction are orthogonal to each other.

[0035] <1. Overview of Developing Cartridges and Drum Cartridges>

[0036] Figure 1 and Figure 2 This is a three-dimensional view of the developing cartridge 1 and the drum cartridge 2. Figure 1 This indicates that the developing cartridge 1 is installed in the drum cartridge 2. Figure 2 This indicates that the developing cartridge 1 has been removed from the drum unit 2.

[0037] The developing cartridge 1 and the drum cartridge 2 are used in an electrophotographic image forming apparatus. Examples of such an apparatus are laser printers and LED printers. The developing cartridge 1 is detachable from the drum cartridge 2. Furthermore, the drum cartridge 2, on which the developing cartridge 1 is mounted, is detachable from the main frame of the image forming apparatus. Using toner supplied from the developing cartridge 1, the image forming apparatus forms an image on printing paper.

[0038] <2. About the developing box>

[0039] Figure 3 This is a 3D view of developer cartridge 1. (See image below.) Figures 1-3 As shown, the developing cartridge 1 includes a housing 10, a stirrer 20, a developing roller 30, a supply roller 40, and a gear section 50.

[0040] The housing 10 is a container for holding toner, which is used as a developer. The housing 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 housing 10 in a first direction. The second outer surface 12 is located at the other end of the housing 10 in the first direction. The first outer surface 11 and the second outer surface 12 are separated from each other in the first direction.

[0041] Color powder is contained inside the casing 10. Additionally, as... Figure 2 As shown, the housing 10 has an opening 13. The opening 13 is located at one end of the housing 10 in a second direction. The space inside the housing 10 and the space outside the housing 10 communicate through the opening 13. In addition, the housing 10 has a handle 14. The handle 14 is located at the other end of the housing 10 in the second direction.

[0042] The stirrer 20 is located inside the housing 10. For example... Figure 3 As shown, the stirrer 20 has blades 21. The stirrer 20 is capable of rotating around a stirrer shaft L1 extending in a first direction (see reference). Figure 4 Rotation. When the stirrer 20 rotates around the stirrer shaft L1, the color powder inside the housing 10 is stirred by the blades 21.

[0043] The developing roller 30 is capable of rotating around a developing shaft L2 extending in the first direction (see reference). Figure 4 The developing roller 30 is a rotating roller. The developing roller 30 is supported on the housing 10. The developing roller 30 is located at the opening 13. That is, the developing roller 30 is located at one end of the housing 10 in a second direction. The developing roller 30 has a cylindrical outer peripheral surface extending in a first direction. A portion of the outer peripheral surface of the developing roller 30 is exposed to the outside of the housing 10.

[0044] The supply roller 40 is capable of extending about the supply shaft L3 (refer to) in the first direction. Figure 4 A rotating roller. A supply roller 40 is supported on the housing 10. The supply roller 40 is located inside the housing 10. More specifically, the supply roller 40 is located between the developing roller 30 and the agitator 20. The supply roller 40 has a cylindrical outer peripheral surface extending in a first direction. The outer peripheral surface of the developing roller 30 is in contact with the outer peripheral surface of the supply roller 40. Toner inside the housing 10 is supplied to the outer peripheral surface of the developing roller 30 via the outer peripheral surface of the supply roller 40. Thus, the toner is carried on the outer peripheral surface of the developing roller 30.

[0045] The gear section 50 is located on the first outer surface 11 of the housing 10. The gear section 50 includes a gear cover 51, a coupling 52, and a plurality of gears. The gear cover 51 is mounted on the first outer surface 11 of the housing 10. Specifically, the gear cover 51 is fixed to the first outer surface 11 of the housing 10 by a threaded connection. The plurality of gears are located between the first outer surface 11 and the gear cover 51 in a first direction. That is, the plurality of gears are covered by the gear cover 51. The coupling 52 protrudes from the gear cover 51.

[0046] Coupling 52 is capable of revolving around coupling shaft L4 (refer to) extending in the first direction. Figure 4 The image forming apparatus consists of rotating parts. When the drum housing 2, on which the developing cartridge 1 is mounted, is installed on the main frame, the drive shaft of the image forming apparatus is inserted into the coupling 52. Thus, the coupling 52 can rotate together with the drive shaft around the coupling shaft L4. The image forming apparatus transmits driving force to multiple gears via the coupling 52.

[0047] Figure 4 This is a diagram of the developing cartridge 1 with the gear cover 51 removed, viewed along the first direction. Figure 5 This is a partial 3D view of the developing cartridge 1 with the gear cover 51 removed. Figure 6 This is a view of the area near the gear section 50 of the developing cartridge 1, viewed from a direction intersecting the first and second directions. (See diagram below.) Figures 4-6 As shown, the gear section 50 includes a coupling gear 53, a developing roller gear 54, a supply roller gear 55, an idle speed gear 56, a stirrer gear 57, and a detection gear 58.

[0048] The coupling gear 53 is located on the first outer surface 11 of the housing 10. The coupling gear 53 is housed inside the gear cover 51. The coupling 52 and the coupling gear 53 are integrally formed parts. Therefore, the coupling gear 53 rotates together with the coupling 52 about the coupling shaft L4.

[0049] The coupling gear 53 has a large-diameter coupling gear 531 and a small-diameter coupling gear 532. The diameter of the small-diameter coupling gear 532, centered on the coupling shaft L4, is smaller than the diameter of the large-diameter coupling gear 531, also centered on the coupling shaft L4. Furthermore, in the first direction, the small-diameter coupling gear 532 is located between the coupling 52 and the large-diameter coupling gear 531. Both the large-diameter coupling gear 531 and the small-diameter coupling gear 532 have a plurality of teeth around their outer circumference. However, in the figures of this invention, the teeth of the coupling gear 53 are omitted from the illustration.

[0050] The developing roller gear 54 is located on the first outer surface 11 of the housing 10. The developing roller gear 54 is housed inside the gear cover 51. The developing roller gear 54 is connected to one end of the developing roller 30 in a first direction. The developing roller gear 54 has a plurality of teeth around its entire circumference. However, the teeth of the developing roller gear 54 are omitted from the illustrations in the figures of this invention.

[0051] The developing roller gear 54 meshes with the coupling gear 53. More specifically, the developing roller gear 54 meshes with the large-diameter coupling gear 531. The developing roller gear 54 rotates along with the large-diameter coupling gear 531. Furthermore, when the developing roller gear 54 rotates, the developing roller 30 also rotates together with the developing roller gear 54 about the developing shaft L2.

[0052] The supply roller gear 55 is located on the first outer surface 11 of the housing 10. The supply roller gear 55 is housed inside the gear cover 51. The supply roller gear 55 is connected to one end of the supply roller 40 in a first direction. The supply roller gear 55 has a plurality of teeth around its entire circumference. However, the teeth of the supply roller gear 55 are omitted from the illustrations in the figures of the present invention.

[0053] The supply roller gear 55 meshes with the coupling gear 53. More specifically, the supply roller gear 55 meshes with the minor diameter coupling gear 532. The supply roller gear 55 rotates along with the minor diameter coupling gear 532. Furthermore, when the supply roller gear 55 rotates, the supply roller 40 also rotates together with the supply roller gear 55 about the supply shaft L3.

[0054] The idle gear 56 is located on the first outer surface 11 of the housing 10. The idle gear 56 is housed inside the gear cover 51. The idle gear 56 is located between the stirrer gear 57 and the protrusion 15 described later. The idle gear 56 is rotatable about the idle shaft L5 extending in a first direction.

[0055] The idle speed gear 56 has a large-diameter idle speed gear 561 and a small-diameter idle speed gear 562. The diameter of the small-diameter idle speed gear 562, centered on the idle speed shaft L5, is smaller than the diameter of the large-diameter idle speed gear 561, also centered on the idle speed shaft L5. Furthermore, in the first direction, the small-diameter idle speed gear 562 is located between the first outer surface 11 of the housing 10 and the large-diameter idle speed gear 561. Both the large-diameter idle speed gear 561 and the small-diameter idle speed gear 562 have a plurality of teeth around their entire circumference.

[0056] The idle speed gear 56 meshes with the coupling gear 53. More specifically, the large-diameter idle speed gear 561 meshes with the small-diameter coupling gear 532. The idle speed gear 56 rotates in tandem with the rotation of the coupling gear 53.

[0057] A stirrer gear 57 is located on the first outer surface 11 of the housing 10. The stirrer gear 57 is housed inside a gear cover 51. The stirrer gear 57 is connected to one end of the stirrer 20 in a first direction. The stirrer gear 57 has a plurality of teeth along its entire circumference. However, the teeth of the stirrer gear 57 are omitted from the illustrations in the figures of this invention.

[0058] The agitator gear 57 meshes with the idle gear 56. More specifically, the agitator gear 57 meshes with the small-diameter idle gear 562. The agitator gear 57 rotates along with the rotation of the small-diameter idle gear 562. Furthermore, when the agitator gear 57 rotates, the agitator 20 also rotates together with the agitator gear 57 about the agitator shaft L1.

[0059] The detection gear 58 is located on the first outer surface 11 of the housing 10. A portion of the detection gear 58 is located inside the gear cover 51. Other portions of the detection gear 58 protrude to the outside of the gear cover 51. The detection gear 58 is rotatable about a detection shaft L6 extending in a first direction. A portion of the outer periphery of the detection gear 58 has a recess 581 that is recessed radially inward. The portion of the outer periphery of the detection gear 58 other than the recess 581 has a plurality of teeth.

[0060] like Figure 5 As shown, in the first direction, the stirrer gear 57 is located between the first outer surface 11 of the housing 10 and the detection gear 58. That is, in the first direction, the detection gear 58 is located further away from the first outer surface 11 of the housing 10 than the stirrer gear 57.

[0061] Figure 7 and Figure 8 This is a cross-sectional view of the developing cartridge 1 and the drum cartridge 2 with the developing cartridge 1 installed in the drum cartridge 2. Figure 7 and Figure 8 This represents a cross-section that includes the detection gear 58 and is perpendicular to the first direction.

[0062] When the developing cartridge 1 is not in use, the detection gear 58 is in the first rotational position. In this case, as... Figure 7 As shown, the detection gear 58 meshes with the idle gear 56. More specifically, the detection gear 58 meshes with the small-diameter idle gear 562. When the drum cassette 2, on which the developing cartridge 1 is mounted, is installed in the image forming apparatus and driving force is supplied from the image forming apparatus to the gear section 50, the detection gear 58 rotates along with the rotation of the idle gear 56. However, when the detection gear 58 rotates to the second rotational position, as... Figure 8 As shown, the idle gear 56 disengages from the detection gear 58. Thus, the detection gear 58 will not rotate further.

[0063] The image forming apparatus includes a sensor that detects the rotation of the detection gear 58. When the drum cassette 2, on which the developing cartridge 1 is mounted, is installed in the image forming apparatus, the sensor detects whether the detection gear 58 rotates from a first rotational position to a second rotational position. Thus, the image forming apparatus can identify whether the developing cartridge 1 is unused or in use. Specifically, if the sensor detects rotation of the detection gear 58 from the first rotational position to the second rotational position, the image forming apparatus identifies the developing cartridge 1 as unused. Conversely, if the sensor does not detect rotation of the detection gear 58 from the first rotational position to the second rotational position, the image forming apparatus identifies the developing cartridge 1 as in use.

[0064] The sensor can, for example, consist of a wobbly rod and a light sensor. In this case, the rod contacts the detection gear 58 and wobbles according to the shape of the recess 581. The light sensor detects the wobbling of the rod. Thus, the image forming apparatus can detect whether the detection gear 58 has rotated from a first rotational position to a second rotational position based on the detection signal from the light sensor.

[0065] <3. About the drum box>

[0066] like Figure 1 and Figure 2 As shown, the drum box 2 has a drum frame 60 and a photosensitive drum 70.

[0067] The drum frame 60 has a first side frame 61, a second side frame 62, and a connecting frame 63. The first side frame 61 is located at one end of the drum frame 60 in a first direction. The second side frame 62 is located at the other end of the drum frame 60 in the first direction. The first side frame 61 and the second side frame 62 are separated from each other in the first direction. The connecting frame 63 connects the first side frame 61 and the second side frame 62 along the first direction.

[0068] The developing cartridge 1 can be attached to and detached from the drum frame 60. When the developing cartridge 1 is installed in the drum frame 60, the developing cartridge 1 is located between the first side frame 61 and the second side frame 62 in a first direction.

[0069] The photosensitive drum 70 is a drum capable of rotating about a drum shaft extending in a first direction. The photosensitive drum 70 is supported on a drum frame 60. The photosensitive drum 70 is located between a first side frame 61 and a second side frame 62 in the first direction. In addition, the photosensitive drum 70 is located at one end of the drum frame 60 in a second direction.

[0070] The photosensitive drum 70 has a cylindrical outer peripheral surface extending along a first direction. The outer peripheral surface of the photosensitive drum 70 is covered with a photosensitive material. With the drum housing 2 mounted on the main frame of the image forming apparatus, the photosensitive drum 70 receives a driving force from the image forming apparatus. As a result, the photosensitive drum 70 rotates about the drum shaft.

[0071] With the developing cartridge 1 mounted on the drum frame 60, the developing roller 30 and the photosensitive drum 70 are arranged in the second direction. More specifically, with the developing cartridge 1 mounted on the drum frame 60, the outer peripheral surface of the developing roller 30 is in contact with the outer peripheral surface of the photosensitive drum 70.

[0072] Toner is supplied from the outer periphery of the developing roller 30 to the outer periphery of the photosensitive drum 70. At this time, the toner moves from the developing roller 30 to the photosensitive drum 70 based on the electrostatic latent image formed on the outer periphery of the photosensitive drum 70. Thus, a toner-based image is formed on the outer periphery of the photosensitive drum 70. Subsequently, the toner-based image is transferred from the photosensitive drum 70 to printing paper.

[0073] <4. Regarding developing pressure>

[0074] Next, the structure in which the developing roller 30 is pressed toward the photosensitive drum 70 when the developing cartridge 1 is installed in the drum cartridge 2 will be described.

[0075] like Figure 7 and Figure 8 As shown, the drum cartridge 2 includes a pressing member 80. The pressing member 80 is used to press the developing cartridge 1 toward the photosensitive drum 70 when the developing cartridge 1 is installed in the drum cartridge 2. The pressing member 80 is provided on the first side frame 61. Alternatively, the same pressing member may be provided on the second side frame 62.

[0076] In addition, such as Figure 7 and Figure 8 As shown, the drum housing 2 has a spring 81. The spring 81 is located between the pressing member 80 and the first side frame 61. The spring 81 is an elastic member capable of stretching and contracting in a second direction. One end of the spring 81 in the second direction is connected to the pressing member 80. The other end of the spring 81 in the second direction is connected to the first side frame 61.

[0077] like Figure 4 , Figure 7 and Figure 8 As shown, the housing 10 of the developing cartridge 1 has a protrusion 15. The protrusion 15 is a projection extending in a first direction from the first outer surface 11 toward the outside of the housing 10. When the developing cartridge 1 is installed in the drum cartridge 2, as... Figure 7 and Figure 8 As shown, the protrusion 15 contacts the pressing member 80. Furthermore, due to the elastic force of the spring 81, the protrusion 15 is subjected to a pressing force in a second direction from the pressing member 80 toward the photosensitive drum 70. Thus, the developing roller 30 and the photosensitive drum 70 come into contact with each other. Additionally, the developing roller 30 presses toward the photosensitive drum 70 in the second direction.

[0078] The protrusion 15 is not located between the first outer surface 11 and the second outer surface 12 in the first direction, but is located on the outer side relative to the first outer surface 11 of the housing 10 in the first direction. Thus, compared to the case where the protrusion 15 is located between the first outer surface 11 and the second outer surface 12 in the first direction, the protrusion 15 can be positioned near the developing roller 30 in the second direction. Therefore, it is possible to prevent the external dimensions of the housing 10 in the second direction from increasing due to the protrusion 15. Furthermore, since the dimension of the internal space of the housing 10 in the second direction is not narrowed due to the protrusion 15, the volume of the internal space of the housing 10 can be ensured.

[0079] The gear cover 51 has an opening 510. The protrusion 15 and the opening 510 are arranged in a second direction. A portion of the protrusion 15 protrudes to the outside of the gear cover 51 through the opening 510. Therefore, when the developing cartridge 1 is installed in the drum cartridge 2, the pressing member 80 can press the portion of the protrusion 15 that protrudes from the gear cover 51.

[0080] The protrusion 15 has a rib 151 protruding in the second direction away from the developing roller 30. When the developing cartridge 1 is installed in the drum cassette 2, the pressing member 80 contacts the outer surface of the rib 151. As a result, the portion of the outer surface of the protrusion 15 pressed by the pressing member 80 is confined to the outer surface of the rib 151. Therefore, it is possible to suppress directional deviation of the pressing force borne by the protrusion 15.

[0081] In the first direction, at least a portion of the protrusion 15 is located at the same position as the coupling gear 53, idle gear 56, agitator gear 57, or detection gear 58. That is, at least a portion of the protrusion 15 is located on the same plane orthogonal to the first direction as the coupling gear 53, idle gear 56, agitator gear 57, or detection gear 58. In this way, compared to the case where the protrusion 15 and the coupling gear 53, idle gear 56, agitator gear 57, or detection gear 58 are arranged at different positions in the first direction, the length of the developing cartridge 1 in the first direction can be reduced.

[0082] In this embodiment, at least a portion of the protrusion 15 is located at the same position as the detection gear 58 in the first direction. That is, at least a portion of the protrusion 15 and the detection gear 58 are located on the same plane orthogonal to the first direction. Therefore, compared to the case where the protrusion 15 and the detection gear 58 are arranged at different positions in the first direction, the length of the developing cartridge 1 in the first direction can be reduced.

[0083] like Figure 7 and Figure 8 As shown by the dashed line, the developing cartridge 1 has a sponge 41. The sponge 41 is located at one end of the supply roller 40 in a first direction. The sponge 41 prevents toner from leaking from the inside of the housing 10 to the outside of the housing 10 along the axis of the supply roller 40.

[0084] The sponge 41 is held in the protrusion 15. Specifically, the protrusion 15 has a rectangular recessed retainer 152 on the side opposite to the rib 151 in the second direction. The sponge 41 is held in the retainer 152. That is, in the structure of this embodiment, the protrusion 15 serves two functions: receiving pressure from the pressing member 80 and holding the sponge 41. In this way, compared with the case where the portion receiving pressure from the pressing member 80 and the portion holding the sponge 41 are provided separately, the housing 10 can be miniaturized. In addition, compared with the case where the portion receiving pressure from the pressing member 80 and the portion holding the sponge 41 are provided separately, the shape of the first outer surface 11 of the housing 10 can be simplified.

[0085] <5. Variations>

[0086] The above describes one embodiment, but the present invention is not limited to the above embodiment.

[0087] In the above embodiment, the surface of the protrusion 15 that contacts the pressing member 80 protrudes in the second direction toward the direction away from the developing roller 30. However, the surface of the protrusion 15 that contacts the pressing member 80 may not necessarily protrude in the second direction toward the direction away from the developing roller 30. For example, the surface of the protrusion 15 that contacts the pressing member 80 may be a flat surface. Alternatively, the surface of the protrusion 15 that contacts the pressing member 80 may be recessed toward the developing roller 30 in the second direction.

[0088] The gear section 50 does not necessarily have to have the structure described in the above embodiment. The number of gears, the position of the gears, the type of gears, the shape of the gears, etc., included in the gear section 50 can also be appropriately changed without departing from the spirit of the present invention.

[0089] Alternatively, the elements appearing in the above-described implementation methods and variations can be appropriately combined, or some elements can be omitted, without causing contradictions.

Claims

1. A developing cartridge, capable of attachment and detachment with respect to a drum cartridge, characterized in that, Possessing: a casing that houses toner and has a first outer surface and a second outer surface that departs from the first outer surface in a first direction; a developing roller that is rotatable about a developing axis that extends in the first direction and is located at an end portion of the casing in a second direction that intersects the first direction; a stirrer that is rotatable about a stirrer axis that extends in the first direction; a coupling gear that is located at the first outer surface; an idling gear that is located at the first outer surface and engages with the coupling gear; a stirrer gear that is located at the first outer surface, connected to the stirrer, and engages with the idling gear; and a detection gear that is located at the first outer surface, engages with the idling gear at a first rotational position, and disengages from the idling gear when the detection gear is rotated from the first rotational position to a second rotational position, the casing has a protrusion that receives a pressing force in the second direction from the drum cartridge and extends in the first direction from the first outer surface toward the outside of the casing, the idling gear is located between the stirrer gear and the protrusion.

2. The developing cartridge according to claim 1, wherein the protrusion has a rib that protrudes in the second direction away from the developing roller, the rib receives the pressing force in the second direction from the drum cartridge.

3. The developing cartridge according to claim 1 or 2, wherein at least a portion of the protrusion is located at the same position as the coupling gear, the idling gear, the stirrer gear, or the detection gear in the first direction.

4. The developing cartridge according to claim 3, wherein at least a portion of the protrusion is located at the same position as the detection gear in the first direction.

5. The developing cartridge according to claim 1 or 2, wherein the idling gear has: a large-diameter idling gear; and a small-diameter idling gear that has a smaller diameter than the large-diameter idling gear, the large-diameter idling gear engages with the coupling gear, the small-diameter idling gear engages with the stirrer gear and the detection gear.

6. The developing cartridge according to claim 1 or 2, wherein the coupling gear has: a large-diameter coupling gear; and a small-diameter coupling gear that has a smaller diameter than the large-diameter coupling gear, the small-diameter coupling gear engages with the idling gear.

7. The developing cartridge according to claim 1 or 2, wherein the detection gear is located at a position that is further away from the first outer surface than the stirrer gear in the first direction.

8. The developing cartridge according to claim 1 or 2, further comprising a developing roller gear that is located at the first outer surface, connected to the developing roller, and engages with the coupling gear.

9. The developing cartridge according to claim 8, wherein the coupling gear has: ​ ​ A large-diameter coupling gear; and A small-diameter coupling gear having a smaller diameter than the large-diameter coupling gear, The large-diameter coupling gear is engaged with the developing roller gear.

10. The process cartridge according to claim 1 or 2, wherein Further provided are: A supply roller rotatable around a supply roller shaft extending in the first direction and in contact with the developing roller; and A supply roller gear provided on the first outer surface, connected to the supply roller, and engaged with the coupling gear.

11. The developing cartridge of claim 10, wherein The coupling gear has: A large-diameter coupling gear; and A small-diameter coupling gear having a smaller diameter than the large-diameter coupling gear, The small-diameter coupling gear is engaged with the supply roller gear.

12. The process cartridge according to claim 1 or 2, wherein Further provided are: A supply roller rotatable around a supply roller shaft extending in the first direction and in contact with the developing roller; and A sponge provided at an end of the supply roller in the first direction, The protrusion holds the sponge.

13. The developing cartridge of claim 1 or 2, wherein Further provided is a gear cover provided on the first outer surface and internally housing the coupling gear, the idling gear, and the agitator gear, A portion of the detection gear is internally provided in the gear cover, and the other portion of the detection gear is externally exposed from the gear cover.

14. The developing cartridge of claim 13, wherein The gear cover has an opening aligned with the protrusion in the second direction.

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