Image forming apparatus

Abstract

To provide an image forming apparatus that can prevent a movement in an axial direction of a developing cartridge relative to a drum frame.SOLUTION: An image forming apparatus comprises: a body housing; a drum unit 50 that is removably mounted in the body housing, and has a plurality of photoconductor drums and a drum frame 53; a plurality of developing cartridges 60 that respectively have developing rollers and are removably mounted in the drum frame 53; and a cover CV that covers part of the developing cartridges 60. The cover CV has: spacers 110 that are sandwiched between a first connection frame 53C of the drum frame 53 and the developing cartridge 60K, or between the two developing cartridges 60, and hold the developing rollers to be separated from the photoconductor drums; and protection walls 160 that are located between one surfaces in a first direction of the developing cartridges 60 and a first side frame 53A of the drum frame 53, and face the developing cartridges 60 and face the first side frame 53A in the first direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus.

Background Art

[0002] Conventionally, as an image forming apparatus, there is known one including a main body housing, a drum unit detachable from the main body housing, four developing cartridges detachable from the drum unit, and a cover (Patent Document 1). In this technology, the drum unit includes four photosensitive drums rotatable about a drum shaft extending in the axial direction.

[0003] The cover has four spacers and a connecting portion connecting the spacers. The cover is attached to the drum unit and the developing cartridges. The spacers are located between the rear frame of the drum unit and the developing cartridge or between two developing cartridges, and position the developing cartridge at a separation position where the developing roller is separated from the photosensitive drum.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, the developing cartridge may move axially with respect to the drum frame of the drum unit due to an impact during transportation of the image forming apparatus or the like. Therefore, it is desired that axial movement of the developing cartridge with respect to the drum frame can be suppressed.

Means for Solving the Problems

[0006] In the first disclosure of the present application, the image forming apparatus includes a main body housing, a drum unit, a first developing cartridge, a second developing cartridge, and a cover. The drum unit is detachable from the main body housing. The drum unit has a first photosensitive drum, a second photosensitive drum, and a drum frame. The first photosensitive drum is rotatable about a first axis extending in the axial direction. The second photosensitive drum is rotatable about a second axis extending in the axial direction. The second photosensitive drum is aligned with the first photosensitive drum. The drum frame has a first side frame, a second side frame, and a connecting frame. The first side frame is located on one side in the axial direction of the first photosensitive drum and the second photosensitive drum. The second side frame is located on the other side in the axial direction of the first photosensitive drum and the second photosensitive drum. The connecting frame extends in the axial direction and connects the first side frame and the second side frame. The first developing cartridge is detachable from the drum frame. The first developing cartridge has a first developing roller that supplies toner to the first photosensitive drum. The second developing cartridge is detachable from the drum frame. The second developing cartridge has a second developing roller that supplies toner to the second photosensitive drum. The cover covers at least a part of the first developing cartridge. The cover has a first spacer and a protective wall. The first spacer holds the first developing roller in a state separated from the first photosensitive drum. The first spacer is sandwiched between the connecting frame and the first developing cartridge, or between the first developing cartridge and the second developing cartridge. The protective wall is located between one side surface in the axial direction of the first developing cartridge and the first side frame. The protective wall faces the first developing cartridge and the first side frame in the axial direction.

[0007] According to the first disclosure, since the cover has a protective wall, the axial movement of the first developing cartridge with respect to the drum frame can be suppressed by the protective wall. Further, even if the first developing cartridge moves axially, the protective wall can suppress the first developing cartridge from directly hitting the first side frame.

[0008] In the second disclosure of the present application, in the image forming apparatus of the first disclosure, the cover has a convex portion protruding from the protective wall toward the first side frame.

[0009] According to the second disclosure, since the cover has a convex portion protruding from the protective wall toward the first side frame, the axial distance from the cover (convex portion) to the first side frame can be made smaller than the axial distance from the protective wall to the first side frame.

[0010] In the third disclosure of the present application, in the image forming apparatus of the second disclosure, the convex portion is a rib extending along the protective wall.

[0011] According to the third disclosure, since the convex portion is a rib extending along the protective wall, the rigidity of the protective wall can be improved.

[0012] In the fourth disclosure of the present application, in the image forming apparatus of the first disclosure, the cover is removable.

[0013] In the fifth disclosure of the present application, in the image forming apparatus of the first disclosure, the protective wall extends from the first spacer.

[0014] According to the fifth disclosure, since the protective wall extends from the highly rigid first spacer that holds the first developing roller in a state separated from the first photosensitive drum, the rigidity of the protective wall can be improved.

[0015] In the sixth disclosure of the present application, in the image forming apparatus of the fourth disclosure, the first spacer is sandwiched between the connection frame and the first developing cartridge. The cover has a second spacer and a first connecting portion. The second spacer holds the second developing roller in a state separated from the second photosensitive drum. The second spacer is sandwiched between the first developing cartridge and the second developing cartridge. The first connecting portion connects the first spacer and the second spacer. The first connecting portion has an elastic portion that allows the first connecting portion to expand and contract in the direction in which the first photosensitive drum and the second photosensitive drum are aligned.

[0016] According to the sixth disclosure, since the first connecting portion has an elastic portion that allows the first connecting portion to expand and contract, dimensional errors between the first spacer and the second spacer can be absorbed. Thereby, it is easy to attach and detach the spacer. Thereby, it is easy to attach and detach the cover.

[0017] In the seventh disclosure of the present application, in the image forming apparatus of the fourth disclosure, the drum unit has a third photosensitive drum. The third photosensitive drum is rotatable about a third axis extending in the axial direction. The third photosensitive drum is aligned with the second photosensitive drum in the arrangement direction in which the first photosensitive drum and the second photosensitive drum are aligned. The image forming apparatus further includes a third developing cartridge. The third developing cartridge is detachable from the drum frame. The third developing cartridge has a third developing roller that supplies toner to the third photosensitive drum. The first spacer is sandwiched between the first developing cartridge and the second developing cartridge. The cover has the second spacer and the first connecting portion. The second spacer holds the second developing roller in a state separated from the second photosensitive drum. The second spacer is sandwiched between the second developing cartridge and the third developing cartridge. The first connecting portion connects the first spacer and the second spacer. The first connecting portion has an elastic portion that allows the first connecting portion to expand and contract in the arrangement direction.

[0018] According to the seventh disclosure, since the first connecting portion has an elastic portion that enables the first connecting portion to expand and contract, dimensional errors between the first spacer and the second spacer can be absorbed. As a result, it is easy to attach and detach the spacers. Consequently, it is easy to attach and detach the cover.

[0019] In the eighth disclosure of the present application, in the image forming apparatus according to the sixth disclosure or the seventh disclosure, the elastic portion is arranged in the axial direction with the second spacer.

[0020] In the ninth disclosure of the present application, in the image forming apparatus according to the fourth disclosure, the cover has a hook that engages with the first developing cartridge from one side in the axial direction.

[0021] According to the ninth disclosure, since the cover has a hook that engages with the first developing cartridge from one side in the axial direction, it is possible to prevent the cover from moving in a direction orthogonal to the axial direction and coming off from the first developing cartridge.

[0022] In the tenth disclosure of the present application, in the image forming apparatus according to the ninth disclosure, the hook has an arm and a claw. The arm is located on one side in the axial direction of the first developing cartridge. The arm extends from the first spacer in the direction in which the first photosensitive drum and the second photosensitive drum are arranged side by side. The claw projects from the arm to the other side in the axial direction. The claw engages with the first developing cartridge.

[0023] According to the tenth disclosure, since the arm of the hook extends from the highly rigid first spacer that holds the first developing roller in a state separated from the first photosensitive drum, the rigidity of the hook can be improved.

[0024] In the eleventh disclosure of the present application, in the image forming apparatus according to the fourth disclosure, the drum unit has a third photosensitive drum and a fourth photosensitive drum. The third photosensitive drum is rotatable about a third axis extending in the axial direction. The third photosensitive drum is arranged side by side with the second photosensitive drum in the arrangement direction in which the first photosensitive drum and the second photosensitive drum are arranged side by side. The fourth photosensitive drum is rotatable about a fourth axis extending in the axial direction. The fourth photosensitive drum is aligned with the third photosensitive drum in the arrangement direction. The image forming apparatus further includes a third developing cartridge and a fourth developing cartridge. The third developing cartridge is detachable from the drum frame. The third developing cartridge has a third developing roller that supplies toner to the third photosensitive drum. The fourth developing cartridge is detachable from the drum frame. The fourth developing cartridge has a fourth developing roller that supplies toner to the fourth photosensitive drum. The first spacer is sandwiched between the connection frame and the first developing cartridge. The cover has a second spacer, a third spacer, a fourth spacer, a first connecting portion, a second connecting portion, and a third connecting portion. The second spacer holds the second developing roller in a state separated from the second photosensitive drum. The second spacer is sandwiched between the first developing cartridge and the second developing cartridge. The third spacer holds the third developing roller in a state separated from the third photosensitive drum. The third spacer is sandwiched between the second developing cartridge and the third developing cartridge. The fourth spacer holds the fourth developing roller in a state separated from the fourth photosensitive drum. The fourth spacer is sandwiched between the third developing cartridge and the fourth developing cartridge. The first connecting portion connects the first spacer and the second spacer. The second connecting portion connects the second spacer and the third spacer. The third connecting portion connects the third spacer and the fourth spacer. The first spacer, the first connecting portion, the second spacer, the second connecting portion, the third spacer, the third connecting portion, and the fourth spacer are integrally formed.

[0025] According to the 11th disclosure, by integrally forming the four spacers and the three connecting portions, the labor required to remove the cover can be reduced. The omission of removing the cover can be suppressed.

Effects of the Invention

[0026] Axial movement of the developing cartridge relative to the drum frame can be suppressed.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0028] Next, embodiments will be described. As shown in FIG. 1, the image forming apparatus 1 is a color printer capable of forming a color image on a sheet S such as paper. The image forming apparatus 1 includes a main body housing 10, a main body cover 11, a sheet supply unit 20, and an image forming unit 30.

[0029] In the drawings to be referred to, in each of the first direction (see FIG. 2), the second direction, and the third direction, one side is indicated by the presence of an arrow, and the other side is indicated by the absence of an arrow. In the present embodiment, the first direction corresponds to the "axial direction".

[0030] The second direction is a direction intersecting the first direction. In the present embodiment, the second direction is orthogonal to the first direction. The third direction is a direction intersecting both the first direction and the second direction. In the present embodiment, the third direction is orthogonal to both the first direction and the second direction.

[0031] The main body housing 10 has an opening 10A. The main body cover 11 opens and closes the opening 10A. The main body cover 11 is movable with respect to the main body housing 10 between a closed position shown by a solid line and an open position shown by a virtual line. Specifically, the main body cover 11 is rotatable with respect to the main body housing 10 between the closed position and the open position. The closed position is a position where the opening 10A is closed. The open position is a position where the opening 10A is open.

[0032] The sheet supply unit 20 includes a sheet tray 21 and a sheet supply mechanism 22. The sheet tray 21 accommodates the sheet S. The sheet supply mechanism 22 includes a pickup roller 23, a separation roller 24, a separation pad 25, a conveyance roller 26, and a registration roller 27.

[0033] The pickup roller 23 feeds out the sheet S from the sheet tray 21. The separation roller 24 and the separation pad 25 separate the sheet S fed out by the pickup roller 23 into individual sheets. The conveyance roller 26 and the registration roller 27 convey the sheet S to the image forming unit 30.

[0034] The image forming unit 30 includes an exposure unit 40, a drum unit 50, four developing cartridges 60, a transfer unit 70, and a fixing unit 80. The exposure unit 40 includes a light source, a deflector, a lens, a mirror, etc. The exposure unit 40 emits a light beam as shown by the dashed line to expose the surface of the photosensitive drum 51.

[0035] The drum unit 50 has four photosensitive drums 51 and four chargers 52. A toner image is formed on the surface of the photosensitive drum 51. The photosensitive drum 51 includes a photosensitive drum 51K, a photosensitive drum 51C, a photosensitive drum 51M, and a photosensitive drum 51Y.

[0036] The photosensitive drum 51K is rotatable about an axis XK extending in the first direction. The photosensitive drum 51C is rotatable about an axis XC extending in the first direction. The photosensitive drum 51M is rotatable about an axis XM extending in the first direction. The photosensitive drum 51Y is rotatable about an axis XY extending in the first direction.

[0037] The photosensitive drum 51C is aligned with the photosensitive drum 51K in the second direction. The photosensitive drum 51M is aligned with the photosensitive drum 51C in the second direction. The photosensitive drum 51Y is aligned with the photosensitive drum 51M in the second direction. In the present embodiment, the second direction corresponds to "the direction in which the first photosensitive drum and the second photosensitive drum are aligned" and "the arrangement direction in which the first photosensitive drum and the second photosensitive drum are aligned".

[0038] The four photosensitive drums 51 are arranged in the order of the photosensitive drum 51Y, the photosensitive drum 51M, the photosensitive drum 51C, and the photosensitive drum 51K from one side to the other side in the second direction. In other words, the four photosensitive drums 51 are arranged in the order of the photosensitive drum 51Y, the photosensitive drum 51M, the photosensitive drum 51C, and the photosensitive drum 51K from the upstream to the downstream in the conveyance direction of the sheet S.

[0039] The charger 52 charges the surface of the photosensitive drum 51.

[0040] The drum unit 50 is detachable from the main body housing 10. Specifically, the drum unit 50 is detachable through the opening 10A with respect to the main body housing 10 in a state where the main body cover 11 is located at the open position indicated by the virtual line.

[0041] The developing cartridge 60 stores toner. The developing cartridge 60 has a developing roller 61. The developing roller 61 supplies toner to the photosensitive drum 51.

[0042] The developing cartridge 60 includes a developing cartridge 60K, a developing cartridge 60C, a developing cartridge 60M, and a developing cartridge 60Y. The developing cartridge 60K, the developing cartridge 60C, the developing cartridge 60M, and the developing cartridge 60Y are individually detachable from the drum frame 53 of the drum unit 50.

[0043] The developing cartridge 60K stores black toner. The developing cartridge 60K has a developing roller 61K. The developing roller 61K supplies black toner to the photosensitive drum 51K. The developing cartridge 60C contains cyan toner. The developing cartridge 60C has a developing roller 61C. The developing roller 61C supplies cyan toner to the photosensitive drum 51C.

[0044] The developing cartridge 60M contains magenta toner. The developing cartridge 60M has a developing roller 61M. The developing roller 61M supplies magenta toner to the photosensitive drum 51M. The developing cartridge 60Y contains yellow toner. The developing cartridge 60Y has a developing roller 61Y. The developing roller 61Y supplies yellow toner to the photosensitive drum 51Y.

[0045] The transfer unit 70 includes a driving roller 71, a driven roller 72, an endless transfer belt 73, and four transfer rollers 74. The transfer belt 73 is spanned between the driving roller 71 and the driven roller 72. The outer surface of the transfer belt 73 contacts the photosensitive drum 51. The transfer roller 74 is disposed inside the transfer belt 73. The transfer roller 74 sandwiches the transfer belt 73 between it and the photosensitive drum 51.

[0046] The fixing unit 80 includes a heating roller 81 and a pressure roller 82. The heating roller 81 heats the sheet S. The pressure roller 82 sandwiches the sheet S between it and the heating roller 81.

[0047] The charger 52 charges the surface of the photosensitive drum 51. The exposure unit 40 emits a light beam onto the surface of the charged photosensitive drum 51. Thereby, an electrostatic latent image based on the image data is formed on the photosensitive drum 51. The developing roller 61 supplies toner to the surface of the exposed photosensitive drum 51. Thereby, a toner image is formed on the photosensitive drum 51.

[0048] The photosensitive drum 51 and the transfer roller 74 convey the sheet S supplied from the registration roller 27. Thereby, the toner image formed on the photosensitive drum 51 is transferred to the sheet S. The heating roller 81 and the pressure roller 82 convey the sheet S to which the toner image has been transferred. Thereby, the toner image transferred to the sheet S is fixed to the sheet S. The intermediate discharge roller 15 and the discharge roller 16 discharge the sheet S to which the toner image has been fixed to the discharge tray 13.

[0049] As shown in FIG. 2, the image forming apparatus 1 further includes a cover CV. The drum unit 50 has a drum frame 53.

[0050] The drum frame 53 rotatably supports the photosensitive drums 51K, 51C, 51M, and 51Y. The drum frame 53 includes a first side frame 53A, a second side frame 53B, a first connection frame 53C as a connection frame, and a second connection frame 53D.

[0051] The first side frame 53A is located on one side in the first direction of the photosensitive drums 51K, 50C, 50M, and 50Y. The first side frame 53A extends in the second direction. The second side frame 53B is located on the other side in the first direction of the photosensitive drums 51K, 50C, 50M, and 50Y. The second side frame 53B extends in the second direction. The first side frame 53A and the second side frame 53B face each other in the first direction.

[0052] The first connection frame 53C is located at the other end in the second direction of the drum frame 53. The first connection frame 53C extends in the first direction. The first connection frame 53C connects the first side frame 53A and the second side frame 53B. Specifically, the first connection frame 53C connects the other end in the second direction of the first side frame 53A and the other end in the second direction of the second side frame 53B.

[0053] The second connection frame 53D is located at one end of the drum frame 53 in the second direction. The second connection frame 53D extends in the first direction. The second connection frame 53D connects one end of the first side frame 53A in the second direction and one end of the second side frame 53B in the second direction. The first connection frame 53C and the second connection frame 53D face each other in the second direction.

[0054] The cover CV is attached to the drum unit 50 and the developing cartridge 60. The cover CV covers a part of the developing cartridge 60 in a state of being attached to the drum unit 50 and the developing cartridge 60.

[0055] Specifically, the cover CV includes a first cover CV1 and a second cover CV2. The first cover CV1 covers one end of the developing cartridges 60K, 60C, 60M, 60Y in the first direction from one side in the third direction. The second cover CV2 covers the other end of the developing cartridges 60K, 60C, 60M, 60Y in the first direction from one side in the third direction.

[0056] As shown in FIG. 3, the cover CV (CV1, CV2) is detachable from the drum unit 50 and the developing cartridge 60. The cover CV is attached when transporting the image forming apparatus 1 or the like. The cover CV is removed when using the image forming apparatus 1. The cover CV is detachable from the drum unit 50 and the developing cartridge 60.

[0057] As shown in FIGS. 4(a) and (b), the first cover CV1 has four spacers 110, one spacer 120, three connecting parts 130, one connecting part 140, a mounting part 150, four protective walls 160, and four hooks 170.

[0058] The spacers 110 include a spacer 110K, a spacer 110C, a spacer 110M, and a spacer 110Y.

[0059] As shown in FIG. 5, the spacer 110K is a portion that holds the developing roller 61K in a state separated from the photosensitive drum 51K. The spacer 110K is sandwiched between the first connection frame 53C and the developing cartridge 60K. Specifically, the spacer 110K is sandwiched between one end in the first direction of the first connection frame 53C and one end in the first direction of the developing cartridge 60K.

[0060] The spacer 110C is a portion that holds the developing roller 61C in a state separated from the photosensitive drum 51C. The spacer 110C is sandwiched between the developing cartridge 60K and the developing cartridge 60C. Specifically, the spacer 110C is sandwiched between one end in the first direction of the developing cartridge 60K and one end in the first direction of the developing cartridge 60C.

[0061] The spacer 110M is a portion that holds the developing roller 61M in a state separated from the photosensitive drum 51M. The spacer 110M is sandwiched between the developing cartridge 60C and the developing cartridge 60M. Specifically, the spacer 110M is sandwiched between one end in the first direction of the developing cartridge 60C and one end in the first direction of the developing cartridge 60M.

[0062] The spacer 110Y is a portion that holds the developing roller 61Y in a state separated from the photosensitive drum 51Y. The spacer 110Y is sandwiched between the developing cartridge 60M and the developing cartridge 60Y. Specifically, the spacer 110Y is sandwiched between one end in the first direction of the developing cartridge 60M and one end in the first direction of the developing cartridge 60Y.

[0063] The spacer 120 is a portion that suppresses the movement of the developing cartridge 60 in the second direction with respect to the drum frame 53. The spacer 120 is sandwiched between the developing cartridge 60Y and the second connection frame 53D. Specifically, the spacer 120 is sandwiched between one end in the first direction of the developing cartridge 60Y and one end in the first direction of the second connection frame 53D.

[0064] The connecting portion 130 includes a connecting portion 130A, a connecting portion 130B, and a connecting portion 130C. The connecting portion 130A is a portion that connects the spacer 110K and the spacer 110C. The connecting portion 130B is a portion that connects the spacer 110C and the spacer 110M. The connecting portion 130C is a portion that connects the spacer 110M and the spacer 110Y.

[0065] In the present embodiment, the connecting portions 130A, 130B, and 130C have substantially the same structure. Hereinafter, the structure of the connecting portion 130A will be described as a representative. As shown in FIGS. 6(a) and 6(b), the connecting portion 130A (130) has an extending portion 131 and an elastic portion 132.

[0066] The extending portion 131 is a plate-like portion that extends long in the second direction. The other end of the extending portion 131 in the second direction is connected to the spacer 110. One end of the extending portion 131 in the second direction is connected to the elastic portion 132. The extending portion 131 extends along one end face of the developing cartridge 60 in the third direction.

[0067] The developing cartridge 60 has a first convex portion 62A that protrudes toward one side in the third direction at one end in the first direction. The first convex portion 62A extends in the second direction. The extending portion 131 is located on the other side of the first convex portion 62A in the first direction. The extending portion 131 extends along the first convex portion 62A. One end face of the extending portion 131 (the first cover CV1) in the third direction is substantially flush with one end face of the first convex portion 62A in the third direction.

[0068] The extending portion 131 is located between two spacers 110 arranged in the second direction.

[0069] The elastic portion 132 is a portion having a U-shaped opening that opens to one side in the third direction when viewed from the first direction. One end of the elastic portion 132 in the second direction is connected to the spacer 110 located on one side in the second direction among the two spacers 110 arranged in the second direction.

[0070] The elastic portion 132 is elastically deformable in the second direction. Specifically, the elastic portion 132 is elastically deformable such that the U-shaped opening becomes wider or narrower in the second direction. Thereby, the elastic portion 132 enables the connecting portion 130 to expand and contract in the second direction.

[0071] The elastic portion 132 is arranged side by side with the spacer 110 in the first direction. Specifically, the elastic portion 132 of the connecting portion 130A is arranged side by side with the spacer 110C in the first direction and is located on the other side of the spacer 110C in the first direction. Also, the elastic portion 132 of the connecting portion 130B is arranged side by side with the spacer 110M in the first direction and is located on the other side of the spacer 110M in the first direction. Also, although not shown in the figure, the elastic portion 132 of the connecting portion 130C is arranged side by side with the spacer 110Y in the first direction and is located on the other side of the spacer 110Y in the first direction.

[0072] As shown in FIGS. 4(a) and (b), the connecting portion 140 is a portion that connects the spacer 110Y and the spacer 120. The connecting portion 140 is plate-shaped and extends long in the second direction. The other end of the connecting portion 140 in the second direction is connected to the spacer 110Y. One end of the connecting portion 140 in the second direction is connected to the spacer 120.

[0073] The connecting portion 140 extends along one end face of the developing cartridge 60Y in the third direction (see FIG. 2). The connecting portion 140 is located on the other side of the first convex portion 62A of the developing cartridge 60Y in the first direction. The connecting portion 140 extends along the first convex portion 62A of the developing cartridge 60Y.

[0074] The attachment part 150 is a part attached to the drum unit 50. The attachment part 150 extends from the spacer 120 toward one side in the second direction, bends, and extends toward the other side in the third direction. The attachment part 150 has a claw 151 at its tip. The claw 151 is a part that engages with the drum frame 53.

[0075] As shown in FIGS. 7(a) and 7(b), the protective wall 160 is a wall that intersects the first direction. In this embodiment, the protective wall 160 is orthogonal to the first direction. The protective wall 160 extends from the spacer 110. Specifically, the protective wall 160 has a first part 161 and a second part 162.

[0076] The first part 161 extends from one end of the spacer 110 in the first direction toward one side in the second direction. The second part 162 extends from the first part 161 toward the other side in the third direction.

[0077] The first cover CV1 further has a convex part 180. The convex part 180 protrudes from the protective wall 160 toward one side in the first direction. In other words, the convex part 180 protrudes from the protective wall 160 toward the first side frame 53A of the drum frame 53.

[0078] The convex part 180 is a rib that extends along the protective wall 160. In this embodiment, the convex part 180 extends in the third direction. Specifically, the convex part 180 extends in the third direction from the first part 161 to the second part 162 of the protective wall 160. A plurality of convex parts 180 are provided side by side in the second direction. Specifically, two convex parts 180 are provided side by side in the second direction.

[0079] As shown in FIG. 8, the protective wall 160 is located between the first side surface 63A of the developing cartridge 60 and the first side frame 53A of the drum frame 53. Specifically, the second part 162 of the protective wall 160 is located between the first side surface 63A of the developing cartridge 60 and the first side frame 53A. The first side surface 63A is one side surface of the developing cartridge 60 in the first direction.

[0080] The protective wall 160 faces the developing cartridge 60 in the first direction and faces the first side frame 53A. Specifically, in the first direction, the second portion 162 of the protective wall 160 faces the developing cartridge 60 and faces the first side frame 53A.

[0081] As shown in FIGS. 7(a) and (b), the hook 170 is a portion that engages with the developing cartridge 60 from one side in the first direction. The hook 170 has an arm 171 and a claw 172.

[0082] The arm 171 is located on one side of the developing cartridge 60 in the first direction. The arm 171 extends from the spacer 110 in the second direction. Specifically, the arm 171 extends from one end of the spacer 110 in the first direction toward one side in the second direction. In this embodiment, the other end of the arm 171 in the second direction is integrated with the first portion 161 of the protective wall 160.

[0083] The claw 172 protrudes from one end of the arm 171 in the second direction toward the other side in the first direction. The claw 172 engages with the developing cartridge 60. The developing cartridge 60 has a first recess 64A on the first side surface 63A. The first recess 64A has a shape that is recessed toward the other side in the first direction. The hook 170 has the claw 172 engaged with the first recess 64A from one side in the first direction.

[0084] In this embodiment, the spacer 110K, the connecting portion 130A, the spacer 110C, the connecting portion 130B, the spacer 110M, the connecting portion 130C, and the spacer 110Y are integrally formed. Specifically, the spacers 110, 120, the connecting portions 130, 140, the mounting portion 150, the protective wall 160, the hook 170, and the convex portion 180 are integrally formed. The first cover CV1 is made of a resin such as polypropylene, for example.

[0085] Next, the second cover CV2 will be described. For the second cover CV2, elements having the same functions as those of each part of the first cover CV1 are denoted by the same reference numerals, and mainly, the differences from the first cover CV1 will be described.

[0086] As shown in FIGS. 9(a) and (b), the second cover CV2 includes four spacers 110, one spacer 120, three connecting parts 130, one connecting part 140, a mounting part 150, four protective walls 160, and four hooks 170. In this embodiment, the second cover CV2 does not have a convex portion 180 (see FIG. 7).

[0087] The spacer 110 includes a spacer 110K, a spacer 110C, a spacer 110M, and a spacer 110Y.

[0088] As shown in FIG. 10, the spacer 110K is sandwiched between the other end in the first direction of the first connection frame 53C and the other end in the first direction of the developing cartridge 60K. The spacer 110C is sandwiched between the other end in the first direction of the developing cartridge 60K and the other end in the first direction of the developing cartridge 60C.

[0089] The spacer 110M is sandwiched between the other end in the first direction of the developing cartridge 60C and the other end in the first direction of the developing cartridge 60M. The spacer 110Y is sandwiched between the other end in the first direction of the developing cartridge 60M and the other end in the first direction of the developing cartridge 60Y.

[0090] The spacer 120 is sandwiched between the other end in the first direction of the developing cartridge 60Y and the other end in the first direction of the second connection frame 53D.

[0091] As shown in FIGS. 11(a) and (b), the connecting part 130 includes a connecting part 130A, a connecting part 130B, and a connecting part 130C. The connecting parts 130A, 130B, and 130C each have an extending part 131 and an elastic part 132.

[0092] The developing cartridge 60 has, at the other end in the first direction, a second convex portion 62B that protrudes toward one side in the third direction. The second convex portion 62B extends in the second direction. The extending portion 131 is located on one side in the first direction of the second convex portion 62B. The extending portion 131 extends along the second convex portion 62B. One end face in the third direction of the extending portion 131 (the second cover CV2) is substantially flush with one end face in the third direction of the second convex portion 62B.

[0093] The extending portion 131 is located on one side in the second direction of the spacer 110K. The extending portion 131 is located on one side in the first direction of the spacers 110C, 110M, and 110Y.

[0094] One end in the second direction of the elastic portion 132 is connected to the other end in the second direction of another connecting portion 130 that is located on one side in the second direction. The elastic portion 132 enables the connecting portion 130 to expand and contract in the second direction.

[0095] The elastic portion 132 of the connecting portion 130A is aligned with the spacer 110C in the first direction and is located on one side in the first direction of the spacer 110C. Also, the elastic portion 132 of the connecting portion 130B is aligned with the spacer 110M in the first direction and is located on one side in the first direction of the spacer 110M. Although not shown, the elastic portion 132 of the connecting portion 130C is aligned with the spacer 110Y in the first direction and is located on one side in the first direction of the spacer 110Y.

[0096] As shown in FIG. 2, the connecting portion 140 of the second cover CV2 extends along one end face in the third direction of the developing cartridge 60Y. The connecting portion 140 is located on one side in the first direction of the second convex portion 62B of the developing cartridge 60Y. The connecting portion 140 extends along the second convex portion 62B of the developing cartridge 60Y.

[0097] As shown in FIG. 9(a), the protective wall 160 includes one first protective wall 160A and three second protective walls 160B. As shown in FIG. 12(a), the first protective wall 160A extends from the spacer 110K. Specifically, the first protective wall 160A protrudes from the other end of the spacer 110K in the first direction toward one side in the second direction and extends toward the other side in the third direction.

[0098] The second protective wall 160B extends from the corresponding spacers 110C, 110K, 110Y. To describe it representatively, the second protective wall 160B extends from the other end of the spacer 110C in the first direction toward the other side in the third direction and further extends toward one side in the second direction.

[0099] As shown in FIG. 8, the protective walls 160(160A, 160B) of the second cover CV2 are located between the second side surface 63B of the developing cartridge 60 and the second side frame 53B of the drum frame 53. The second side surface 63B is the other side surface of the developing cartridge 60 in the first direction. The protective wall 160 faces the developing cartridge 60 and the second side frame 53B in the first direction.

[0100] As shown in FIGS. 12(a) and (b), the hook 170 is a portion that engages with the developing cartridge 60 from the other side in the first direction. The hook 170 has an arm 171 and a claw 172.

[0101] The arm 171 is located on the other side of the developing cartridge 60 in the first direction. The arm 171 extends from the spacer 110 in the second direction. Specifically, the arm 171 extends from the other end of the spacer 110 in the first direction toward one side in the second direction. In this embodiment, the other end of the arm 171 in the second direction is integrated with the protective wall 160.

[0102] The claw 172 protrudes from one end of the arm 171 in the second direction toward one side in the first direction. The claw 172 engages with the developing cartridge 60. The developing cartridge 60 has a second recess 64B on the second side surface 63B. The second recess 64B has a shape that is recessed toward one side in the first direction. The hook 170 is such that the claw 172 engages with the second recess 64B from the other side in the first direction.

[0103] Regarding the second cover CV2, the spacers 110, 120, the connecting portions 130, 140, the mounting portion 150, the protective wall 160, and the hook 170 are integrally formed. The second cover CV2 is made of a resin such as polypropylene, for example.

[0104] Next, the operation and effects of the embodiment will be described. Since the cover CV has the protective wall 160, the protective wall 160 can suppress the movement of the developing cartridge 60 in the first direction with respect to the drum frame 53.

[0105] Specifically, the protective wall 160 of the first cover CV1 can suppress the movement of the developing cartridge 60 toward one side in the first direction with respect to the drum frame 53. Also, the protective wall 160 (160A, 160B) of the second cover CV2 can suppress the movement of the developing cartridge 60 toward the other side in the first direction with respect to the drum frame 53.

[0106] Also, even if the developing cartridge 60 moves toward one side in the first direction, the protective wall 160 of the first cover CV1 can suppress the developing cartridge 60 from directly hitting the first side frame 53A. Also, the protective wall 160 of the second cover CV2 can suppress the developing cartridge 60 from directly hitting the second side frame 53B.

[0107] The first cover CV1 has a convex portion 180 that protrudes from the protective wall 160 toward the first side frame 53A. Thereby, the distance in the first direction from the first cover CV1 (convex portion 180) to the first side frame 53A can be made smaller than the distance in the first direction from the protective wall 160 to the first side frame 53A.

[0108] As a result, even if the developing cartridge 60 moves to one side in the first direction and the developing cartridge 60 hits the first side frame 53A via the protective wall 160 and the convex portion 180, the amount of movement of the developing cartridge 60 to one side in the first direction can be reduced. Further, even if the developing cartridge 60 moves to one side in the first direction and the developing cartridge 60 hits the first side frame 53A via the protective wall 160 and the convex portion 180, the impact can be reduced.

[0109] Since the convex portion 180 is a rib extending along the protective wall 160, the rigidity of the protective wall 160 can be improved. Thereby, the movement of the developing cartridge 60 to one side in the first direction can be firmly suppressed by the protective wall 160 of the first cover CV1.

[0110] Since the protective wall 160 extends from a highly rigid spacer 110 that holds the developing roller 61 in a state separated from the photosensitive drum 51, the rigidity of the protective wall 160 can be improved.

[0111] Further, since the protective wall 160 extends from the spacer 110, the cover CV can be suppressed from protruding to one side in the third direction more than the developing cartridge 60. Specifically, compared with the case where the protective wall of the first cover CV1 extends from the connecting portion 130, straddles the first convex portion 62A, and extends between the first side surface 63A and the first side frame 53A, the first cover CV1 can be suppressed from protruding to one side in the third direction more than the first convex portion 62A.

[0112] Similarly, compared with the case where the protective wall of the second cover CV2 extends from the connecting portion 130, straddles the second convex portion 62B, and extends between the second side surface 63B and the second side frame 53B, the second cover CV2 can be suppressed from protruding to one side in the third direction more than the second convex portion 62B.

[0113] By having the connecting portion 130 include an elastic portion 132 that enables the connecting portion 130 to expand and contract, dimensional errors between the two spacers 110 can be absorbed. As a result, it is easy to attach and detach the spacers 110. Consequently, it is easy to attach and detach the cover CV.

[0114] Since the first cover CV1 has a hook 170 that engages with the developing cartridge 60 from one side in the first direction, it is possible to prevent the first cover CV1 from moving in a direction orthogonal to the first direction and coming off the developing cartridge 60.

[0115] Also, since the second cover CV2 has a hook 170 that engages with the developing cartridge 60 from the other side in the first direction, it is possible to prevent the second cover CV2 from moving in a direction orthogonal to the first direction and coming off the developing cartridge 60.

[0116] Since the arm 171 of the hook 170 extends from a highly rigid spacer 110 that holds the developing roller 61 in a state separated from the photosensitive drum 51, the rigidity of the hook 170 can be improved.

[0117] Also, since the hook 170 extends from the spacer 110, it is possible to prevent the cover CV from protruding to one side in the third direction beyond the developing cartridge 60. Specifically, compared to a case where the hook of the first cover CV1 extends from, for example, the connecting portion 130, straddles the first convex portion 62A, and extends to one side in the first direction of the developing cartridge 60, it is possible to prevent the first cover CV1 from protruding to one side in the third direction beyond the first convex portion 62A.

[0118] Similarly, compared to a case where the hook of the second cover CV2 extends from, for example, the connecting portion 130, straddles the second convex portion 62B, and extends to the other side in the first direction of the developing cartridge 60, it is possible to prevent the second cover CV2 from protruding to one side in the third direction beyond the second convex portion 62B.

[0119] Four spacers 110, three connecting parts 130, etc. of the first cover CV1 are integrally formed, so that, for example, when the cover having the spacers is provided for every four developing cartridges 60, the labor for removing the first cover CV1 can be reduced compared to that case. The oversight of removing the first cover CV1 can be suppressed.

[0120] Similarly, four spacers 110, three connecting parts 130, etc. of the second cover CV2 are integrally formed, so that the labor for removing the second cover CV2 can be reduced. The oversight of removing the second cover CV2 can be suppressed.

[0121] As described above, although the embodiments have been described, the image forming apparatus can be appropriately modified and implemented as exemplified below.

[0122] In the above-described embodiment, the convex portion 180 is a rib extending along the protective wall 160. However, for example, the convex portion may be a dot-like protrusion or the like. Further, the first cover CV1 may be configured not to have the convex portion 180. Further, the second cover CV2 may have a convex portion protruding from the protective wall 160 toward the second side frame 53B.

[0123] In the above-described embodiment, the elastic portion 132 was arranged side by side with the spacer 110 in the first direction. However, for example, the elastic portion may be located on one side in the third direction of the developing cartridge. Further, the connecting part may be configured not to have the elastic portion.

[0124] In the above-described embodiment, the arm 171 of the hook 170 extended from the spacer 110. However, for example, the arm of the hook may extend from the connecting part. Further, in the above-described embodiment, the hook 170 had a configuration having the arm 171 and the claw 172. However, for example, the hook may have a configuration consisting of a claw protruding from the protective wall toward the developing cartridge. Further, the cover may be configured not to have the hook.

[0125] In the above-described embodiment, the protective wall 160 extended from the spacer 110. However, for example, the protective wall may extend from the connecting part.

[0126] In the above-described embodiment, the first cover CV1 has a configuration in which four spacers 110 and three connecting portions 130 are integrally formed, but the present invention is not limited thereto. For example, a configuration in which a plurality of covers having a configuration in which two spacers are connected by one connecting portion may be provided. Further, for example, a configuration in which a cover having a spacer and a protective wall is provided for each developing cartridge may be provided. Further, for example, a configuration in which one cover is provided in which the first cover CV1 and the second cover CV2 of the above-described embodiment are connected and integrated may be provided.

[0127] In the above-described embodiment, the image forming apparatus 1 is a printer. However, for example, the image forming apparatus may be a copying machine or a multifunction peripheral.

[0128] Each element described in the above-described embodiment and modification examples may be implemented in any combination.

Explanation of Reference Numerals

[0129] 1 Image forming apparatus 10 Main body housing 50 Drum unit 51K, 51C, 51M, 51Y Photosensitive drum 53 Drum frame 53A First side frame 53B Second side frame 53C First connection frame 60K, 60C, 60M, 60Y Developing cartridge 61K, 61C, 61M, 61Y Developing roller 63A First side 110 Spacer 160 Protective wall CV Cover XK, XC, XM, XY Axes

Claims

1. A main body housing, A drum unit detachable from the main body housing, A first photosensitive drum rotatable about a first shaft extending in the axial direction, A second photosensitive drum rotatable about a second shaft extending in the axial direction, the second photosensitive drum being aligned with the first photosensitive drum, A drum frame, A first side frame located on one side in the axial direction of the first photosensitive drum and the second photosensitive drum, A second side frame located on the other side in the axial direction of the first photosensitive drum and the second photosensitive drum, A connecting frame extending in the axial direction and connecting the first side frame and the second side frame, and a drum frame having the connecting frame, A drum unit, A first developing cartridge detachable from the drum frame, the first developing cartridge having a first developing roller for supplying toner to the first photosensitive drum, A second developing cartridge detachable from the drum frame, the second developing cartridge having a second developing roller for supplying toner to the second photosensitive drum, A cover covering at least a part of the first developing cartridge, A first spacer holding the first developing roller in a state separated from the first photosensitive drum, the first spacer being sandwiched between the connecting frame and the first developing cartridge or between the first developing cartridge and the second developing cartridge, A protective wall located between one side surface in the axial direction of the first developing cartridge and the first side frame, the protective wall facing the first developing cartridge and the first side frame in the axial direction, An image forming apparatus comprising a cover.

2. The image forming apparatus according to claim 1, wherein the cover has a convex portion protruding from the protective wall toward the first side frame.

3. The image forming apparatus according to claim 2, wherein the convex portion is a rib extending along the protective wall.

4. The image forming apparatus according to claim 1, wherein the cover is removable.

5. The image forming apparatus according to claim 1, wherein the protective wall extends from the first spacer.

6. The first spacer is sandwiched between the connecting frame and the first developing cartridge, The cover, A second spacer that holds the second developing roller in a state separated from the second photosensitive drum, the second spacer being sandwiched between the first developing cartridge and the second developing cartridge, A first connecting portion that connects the first spacer and the second spacer, The image forming apparatus according to claim 4, wherein the first connecting portion has an elastic portion that enables the first connecting portion to expand and contract in a direction in which the first photosensitive drum and the second photosensitive drum are arranged side by side.

7. The drum unit is a third photosensitive drum rotatable about a third axis extending in the axial direction, the drum unit having a third photosensitive drum arranged side by side with the second photosensitive drum in an arrangement direction in which the first photosensitive drum and the second photosensitive drum are arranged side by side, The image forming apparatus further includes a third developing cartridge detachable from the drum frame, the third developing cartridge having a third developing roller that supplies toner to the third photosensitive drum, The first spacer is sandwiched between the first developing cartridge and the second developing cartridge, The cover, A second spacer that holds the second developing roller in a state separated from the second photosensitive drum, the second spacer being sandwiched between the second developing cartridge and the third developing cartridge, A first connecting portion that connects the first spacer and the second spacer, The image forming apparatus according to claim 4, wherein the first connecting portion has an elastic portion that enables the first connecting portion to expand and contract in the arrangement direction.

8. The image forming apparatus according to claim 6 or 7, wherein the elastic portion is arranged side by side with the second spacer in the axial direction.

9. The image forming apparatus according to claim 4, wherein the cover has a hook that engages with the first developing cartridge from one side in the axial direction.

10. The hook, An arm located on one side in the axial direction of the first developing cartridge, the arm extending from the first spacer in a direction in which the first photosensitive drum and the second photosensitive drum are arranged side by side, The image forming apparatus according to claim 9, further comprising a claw that protrudes from the arm to the other side in the axial direction and engages with the first developing cartridge.

11. The drum unit, A third photosensitive drum rotatable about a third axis extending in the axial direction, the third photosensitive drum being aligned with the second photosensitive drum in the arrangement direction in which the first photosensitive drum and the second photosensitive drum are arranged, A fourth photosensitive drum rotatable about a fourth axis extending in the axial direction, the fourth photosensitive drum being aligned with the third photosensitive drum in the arrangement direction, and having, The image forming apparatus, A third developing cartridge detachable from the drum frame, the third developing cartridge having a third developing roller for supplying toner to the third photosensitive drum, A fourth developing cartridge detachable from the drum frame, the fourth developing cartridge having a fourth developing roller for supplying toner to the fourth photosensitive drum, and further comprising, The first spacer is sandwiched between the connection frame and the first developing cartridge, The cover, A second spacer for holding the second developing roller in a state separated from the second photosensitive drum, the second spacer being sandwiched between the first developing cartridge and the second developing cartridge, A third spacer for holding the third developing roller in a state separated from the third photosensitive drum, the third spacer being sandwiched between the second developing cartridge and the third developing cartridge, A fourth spacer for holding the fourth developing roller in a state separated from the fourth photosensitive drum, the fourth spacer being sandwiched between the third developing cartridge and the fourth developing cartridge, A first connecting portion connecting the first spacer and the second spacer, A second connecting portion connecting the second spacer and the third spacer, A third connecting portion connecting the third spacer and the fourth spacer, and having, The image forming apparatus according to claim 4, characterized in that the first spacer, the first connecting portion, the second spacer, the second connecting portion, the third spacer, the third connecting portion and the fourth spacer are integrally formed.

Images