Image forming apparatus

Abstract

To provide an image forming apparatus that, with one operation, can bring photoconductor drums into contact with an intermediate transfer belt and subsequently move developing rollers toward the photoconductor drums.SOLUTION: An image forming apparatus comprises: a body housing; a cover; drum units (drum cartridges 40); developing units (developing cartridges 50); and an intermediate transfer belt 63. In conjunction with the movement of the cover from an open position to a closed position, photoconductor drums, the intermediate transfer belt 63, and developing rollers take a first state where the photoconductor drums are separated from the intermediate transfer belt 63 and the developing rollers are separated from the photoconductor drums, a second state where the photoconductor drums are in contact with the intermediate transfer belt 63 and the developing rollers are separated from the photoconductor drums, and a third state where the photoconductor drums are in contact with the intermediate transfer belt 63 and the developing rollers are closer to the photoconductor drums than the first state.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to an image forming apparatus including a drum cartridge and a developing cartridge that are detachable from a main body housing. [Background technology]

[0002] Conventionally, there is known an image forming apparatus in which a drum cartridge and a developing cartridge are separately detachable from a main body housing (see Patent Document 1). In this technology, the drum cartridge and the developing cartridge are detachable in the axial direction of the photosensitive drum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-77459 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration disclosed in Patent Document 1, in order to prevent the photosensitive drum from coming into contact with the intermediate transfer belt and damaging the photosensitive drum and intermediate transfer belt when the drum cartridge is mounted in the main body housing of the image forming apparatus, the photosensitive drum is separated from the intermediate transfer belt when the drum cartridge is mounted in the main body housing. Then, when the cover is moved from the open position to the closed position with the drum cartridge mounted in the main body housing, the drum cartridge moves relative to the intermediate transfer belt and the photosensitive drum comes into contact with the intermediate transfer belt. In addition, in order to prevent the developing roller and the photosensitive drum from coming into contact with each other and being damaged when the developing cartridge is mounted in the main body housing, the developing roller is separated from the photosensitive drum when the developing cartridge is mounted in the main body housing. Then, after the user moves the cover from the open position to the closed position with the drum cartridge and the developing cartridge mounted in the main body housing, the motor and the cam in the main body housing move the developing cartridge relative to the drum cartridge, and the developing roller comes into contact with the photosensitive drum.

[0005] Therefore, before the image forming device could start an image forming operation, two actions were required: a first action in which the user moves the cover from the open position to the closed position, moves the drum cartridge relative to the intermediate transfer belt, and brings the photosensitive drum into contact with the intermediate transfer belt; and a second action in which the motor and cam move the developing cartridge relative to the photosensitive drum after the user moves the cover from the open position to the closed position.

[0006] The present disclosure aims to provide an image forming device that allows a user to move a drum cartridge relative to an intermediate transfer belt by a single action of moving a cover from an open position to a closed position without using a motor, and after bringing a photosensitive drum into contact with the intermediate transfer belt, moves a developing cartridge relative to the drum cartridge. [Means for solving the problem]

[0007] In order to solve the above problem, the image forming apparatus of the present disclosure includes a main body housing having an opening, a cover movable between an open position that opens the opening and a closed position that closes the opening, a drum cartridge, a developing cartridge, an intermediate transfer belt, and a movable cam. The drum cartridge has a photosensitive drum rotatable about a first axis extending in a first direction, and is detachably mountable to the main body casing in the first direction. The developing cartridge has a developing roller rotatable about a second axis extending in the first direction, and is detachable from the main body casing in the first direction. The intermediate transfer belt is located above the drum cartridge and the developing cartridge when the drum cartridge and the developing cartridge are attached to the main body housing. The movable cam is located below the drum cartridge and the developing cartridge when the drum cartridge and the developing cartridge are attached to the main body housing, and is located at a first position when the cover is located at the open position, at a second position while the cover moves from the open position to the closed position, and at a third position when the cover is located at the closed position. When the movable cam is located at the first position, the photosensitive drum is separated from the intermediate transfer belt, and the developing roller is separated from the photosensitive drum. When the movable cam is located at the second position, the photosensitive drum is in contact with the intermediate transfer belt, and the developing roller is separated from the photosensitive drum. When the movable cam is located at the third position, the photosensitive drum comes into contact with the intermediate transfer belt, and the developing roller comes into contact with the photosensitive drum.

[0008] With this configuration, contact between the intermediate transfer belt and the photosensitive drum due to movement of the drum cartridge relative to the intermediate transfer belt, and contact between the photosensitive drum and the developing roller due to movement of the developing cartridge relative to the drum cartridge can be achieved by a single action of the user positioning the cover from the open position to the closed position, without using a motor.

[0009] In the image forming apparatus described above, the drum cartridge may be configured to be aligned with the developing cartridge in a second direction intersecting the first direction when the drum cartridge and the developing cartridge are attached to the main body housing. In the image forming apparatus, the movable cam may be configured to be movable in the first direction as the cover moves from the open position to the closed position.

[0010] In the above-mentioned image forming apparatus, the main body housing may be provided with a first lift and a second lift, the first lift may be configured to engage with the movable cam to move the drum cartridge upward, and the second lift may be configured to engage with the movable cam to move the developing cartridge upward.

[0011] In the image forming apparatus, the first lift may be configured to include a first drum contact portion that comes into contact with the moving cam. The movable cam may be configured to have a first drum separating surface extending in the first direction, a first drum inclined surface, and a first drum contact surface. The first drum inclined surface extends from the first drum separation surface toward the intermediate transfer belt and is inclined with respect to the first direction. The first drum contact surface extends in the first direction from the first drum inclined surface and is closer to the intermediate transfer belt in the up-down direction than the first drum separation surface. The first drum inclined surface is located between the first drum separation surface and the first drum contact surface in the first direction. When the movable cam is located at the first position, the first drum contact portion comes into contact with the first drum separation surface. Furthermore, while the movable cam moves from the first position to the second position, the first drum contact portion comes into contact with the first drum inclined surface. Furthermore, when the movable cam is located at the second position and the third position, the first drum contact portion comes into contact with the first drum contact surface.

[0012] According to this, when the movable cam moves in conjunction with the opening and closing of the cover, the first drum contact portion of the first lift comes into contact with the first drum separation surface, the first drum inclined surface or the first drum contact surface, thereby changing the height position of the first lift, and the drum cartridge can be positioned at a predetermined position.

[0013] In the image forming apparatus described above, the second lift may be configured to include a first developing contact portion that comes into contact with the movable cam. The movable cam may be configured to have a first developer separating surface extending in the first direction, a first developer inclined surface, and a first developer contact surface. The first inclined development surface extends from the first development separation surface toward the intermediate transfer belt and is inclined with respect to the first direction. The first developer contact surface extends in the first direction from the first developer inclined surface and is closer to the intermediate transfer belt in the vertical direction than the first developer separating surface. The first developer inclined surface is located between the first developer separation surface and the first developer contact surface in the first direction. When the movable cam is located at the first position, the first developer contact portion comes into contact with the first developer separating surface. Furthermore, while the movable cam moves from the first position to the third position, the first developer contact portion comes into contact with the first developer inclined surface. Furthermore, when the movable cam is located at the third position, the first developer contact portion comes into contact with the first developer contact surface.

[0014] According to this, when the movable cam moves in conjunction with the opening and closing of the cover, the first developer contact portion of the second lift comes into contact with the first developer separation surface, the first developer inclined surface or the first developer contact surface, thereby changing the height position of the second lift, and the developer cartridge can be positioned at a predetermined position.

[0015] In the image forming apparatus described above, in a movement direction in which the movable cam moves from the first position toward the third position, the downstream end of the first drum contact surface may be configured to be located downstream of the downstream end of the first developing contact surface.

[0016] In the image forming apparatus, the movable cam may be configured to have a second drum separation surface, a second drum inclined surface, and a second drum contact surface. The second drum spacing surface is located away from the first drum spacing surface in the first direction. The second drum inclined surface extends from the second drum separation surface toward the intermediate transfer belt. The second drum inclined surface is inclined with respect to the first direction and is spaced apart from the first drum inclined surface in the first direction. The second drum contact surface extends in the first direction from the second drum inclined surface and is closer to the intermediate transfer belt than the second drum separating surface in the vertical direction and is spaced apart from the first drum contact surface in the first direction. The second drum inclined surface is located between the second drum separation surface and the second drum contact surface in the first direction. The first lift may be configured to include a second drum contact portion that contacts the moving cam. The second drum contact portion is located away from the first drum contact portion in the first direction. When the movable cam is located at the first position, the second drum contact portion comes into contact with the second drum separation surface. Furthermore, while the movable cam moves from the first position to the second position, the second drum contact portion comes into contact with the second drum inclined surface. Furthermore, when the movable cam is located at the second position and the third position, the second drum contact portion comes into contact with the second drum contact surface.

[0017] In the image forming apparatus, the movable cam may be configured to have a second developer separating surface, a second developer inclined surface, and a second developer inclined surface. The second development spaced surface is spaced apart from the first development spaced surface in the first direction. The second inclined development surface extends from the second developing separation surface toward the intermediate transfer belt, and is inclined with respect to the first direction and spaced apart from the first inclined development surface in the first direction. The second developer contact surface extends in the first direction from the second developer inclined surface, is closer to the intermediate transfer belt in the vertical direction than the second developer separating surface, and is located away from the first developer contact surface in the first direction. The second developer inclined surface is located between the second developer separation surface and the second developer contact surface in the first direction. The second lift may be configured to include a second developing contact portion that contacts the moving cam. The second developing contact portion is positioned away from the first developing contact portion in the first direction. When the movable cam is located at the first position, the second developer contact portion comes into contact with the second developer separating surface. Furthermore, while the movable cam moves from the first position to the third position, the second developer contact portion comes into contact with the second developer inclined surface. Furthermore, when the movable cam is located at the third position, the second developer contact portion comes into contact with the second developer contact surface.

[0018] With these configurations, the first lift has two drum contact portions, the second lift has two developer contact portions, and the movable cam presses the two drum contact portions and the two developer contact portions, thereby enabling the drum cartridge and developer cartridge to be stably positioned.

[0019] Furthermore, in the image forming apparatus described above, in a movement direction in which the movable cam moves from the first position toward the third position, a downstream end of the second drum contact surface may be configured to be located downstream of a downstream end of the second developing contact surface.

[0020] In the image forming apparatus, the first lift may be configured to have a drum guide protrusion and a developing guide protrusion. The drum guide protrusion extends in the first direction and serves to guide the drum cartridge. The developing guide protrusion extends in the first direction and serves to guide the developing cartridge. The drum cartridge may be configured to have a drum groove that is guided by the drum guide protrusion. The developing cartridge may be configured to have a developing groove that is guided by the developing guide protrusion.

[0021] In the image forming apparatus, the developing guide protrusion may have a guide hole, and the second lift may be configured to be movable within the guide hole.

[0022] According to this, the drum cartridge and developing cartridge can be moved relative to the intermediate transfer belt by a first lift, and after the positioning of the photosensitive drum relative to the intermediate transfer belt is completed, the developing cartridge can be moved relative to the drum cartridge by a second lift, and the developing roller can be positioned relative to the photosensitive drum.

[0023] The image forming apparatus may be configured to include a paper discharge section for discharging paper, the paper discharge section being located above the intermediate transfer belt.

[0024] The image forming apparatus may be configured to include a paper feed section for feeding paper, the paper feed section being located below the movable cam. Effect of the Invention

[0025] According to the present disclosure, contact between the intermediate transfer belt and the photosensitive drum due to movement of the drum cartridge relative to the intermediate transfer belt, and contact between the photosensitive drum and the developing roller due to movement of the developing cartridge relative to the drum cartridge can be achieved by a single action of the user positioning the cover from the open position to the closed position, without the use of a motor. [Brief description of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a color printer according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view illustrating a cover, a movable cam, and a first lift. [Diagram 3] 1A is a perspective view of a movable cam, and FIG. 1B is a cross-sectional view of the movable cam. [Figure 4]FIG. 2A is a perspective view of a first lift and a second lift, and FIG. 2B is a cross-sectional view of the first lift. [Diagram 5] 4A is an explanatory diagram of the movable cam when it is in a first position, and FIG. 4B is an enlarged view of the movable cam cut in a plane perpendicular to the second direction. [Figure 6] 4A is an explanatory diagram of the movable cam when it is in the second position, and FIG. 4B is an enlarged view of the movable cam cut in a plane perpendicular to the second direction. [Figure 7] 11 is an explanatory diagram of the movable cam when it is in a third position, and shows (a) a cross-sectional view cut along a plane perpendicular to the second direction, and (b) an enlarged view cut along a plane perpendicular to the first direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Next, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings as appropriate. In the following description, first, the overall configuration of a color printer 1 as an example of an image forming apparatus will be described.

[0028] 1, color printer 1 includes a main body housing 2, a paper feed section 3, an image forming section 4, and a paper discharge section 5. The paper feed section 3 supplies paper P to the image forming section 4. The image forming section 4 forms an image on the paper P. The paper discharge section 5 discharges the paper P.

[0029] The paper feed unit 3 is located at the bottom inside the main body housing 2. The paper feed unit 3 includes a paper feed tray 31 and a paper feed mechanism 32. The paper feed tray 31 is detachable from the main body housing 2. The paper feed mechanism 32 transports paper P from the paper feed tray 31 to the image forming unit 4. The paper feed section 3 is located below a moving cam 110, which will be described later.

[0030] The image forming section 4 includes four drum cartridges 40, four developing cartridges 50, an exposure device SU, a transfer unit 60, and a fixing unit .

[0031] Each drum cartridge 40 has a photosensitive drum 41, a charger (not shown), and a drum frame F1. The photosensitive drum 41 is rotatable about a first axis X1 extending in a first direction. When attached to the main body housing 2, the four drum cartridges 40 are aligned in a second direction intersecting the first direction. The first direction is a direction perpendicular to the up-down direction, and the second direction is a direction perpendicular to the first direction and the up-down direction. The up-down direction is the vertical direction.

[0032] Each of the developing cartridges 50 includes a developing roller 51 and a developing frame F2. The developing frame F2 contains a developer. The developing roller 51 is rotatable about a second axis X2 extending in the first direction.

[0033] The drum cartridge 40 and the developing cartridge 50 are aligned in the second direction when the drum cartridge 40 and the developing cartridge 50 are attached to the main body housing 2. As shown in FIG. 2, the drum cartridge 40 is detachable from the main body housing 2 in the first direction. Similarly, the developing cartridge 50 is detachable from the main body housing 2 in the first direction. Each drum cartridge 40 has the same structure. Each developing cartridge 50 has the same structure.

[0034] The exposure device SU is located below each drum cartridge 40. The exposure device SU emits laser light to each photosensitive drum 41.

[0035] The transfer unit 60 is located between the four photosensitive drums 41 and a discharge tray 21 described later. The transfer unit 60 includes a drive roller 61, a driven roller 62, an intermediate transfer belt 63, four primary transfer rollers 64, and a secondary transfer roller 65.

[0036] The intermediate transfer belt 63 is an endless belt. When the drum cartridge 40 and the developing cartridge 50 are attached to the main body casing 2, the intermediate transfer belt 63 is located above the drum cartridge 40 and the developing cartridge 50.

[0037] The primary transfer roller 64 is located inside the intermediate transfer belt 63. The primary transfer roller 64 and the photosensitive drum 41 sandwich the intermediate transfer belt 63 therebetween.

[0038] The secondary transfer roller 65 is located outside the intermediate transfer belt 63. The secondary transfer roller 65 and the drive roller 61 sandwich the intermediate transfer belt 63 therebetween.

[0039] The fixing unit 70 is located above the intermediate transfer belt 63. The fixing unit 70 includes a heating roller 71 and a pressure roller 72. The pressure roller 72 is pressed against the heating roller 71.

[0040] The paper discharge unit 5 is located at the top of the main body housing 2. The paper discharge unit 5 is located above the intermediate transfer belt 63. The paper discharge unit 5 includes a discharge roller 9 and a paper discharge tray 21. The discharge roller 9 transports the paper P toward the paper discharge tray 21.

[0041] In the color printer 1, first, a charger charges the surface of the photosensitive drum 41. Then, an exposure device SU exposes the surface of the photosensitive drum 41. As a result, an electrostatic latent image is formed on the photosensitive drum 41.

[0042] Next, the developing roller 51 supplies the developer to the electrostatic latent image on the photosensitive drum 41. As a result, a developer image is formed on the photosensitive drum 41. Then, the developer image on the photosensitive drum 41 is transferred onto the intermediate transfer belt 63.

[0043] When the paper P passes between the intermediate transfer belt 63 and the secondary transfer roller 65, the developer image on the intermediate transfer belt 63 is transferred onto the paper P. The developer image on the paper P is then fixed by the fixing unit 70. Next, the paper P is discharged to the paper discharge tray 21 by the discharge rollers 9.

[0044] The main body housing 2 has an opening 22A. The opening 22A allows each drum cartridge 40 and each developer cartridge 50 to pass through when the drum cartridge 40 and the developer cartridge 50 are attached or detached in the first direction.

[0045] As shown in FIG. 2, the color printer 1 has a cover C. The cover C is a member for opening and closing the opening 22A. The cover C rotates about a rotation shaft C1 on both sides of the lower end of the cover C. The rotation shaft C1 is inserted into a bearing (not shown) of the main body housing 2. The cover C is movable between an open position (position shown in FIG. 2) where the opening 22A is opened and a closed position (not shown) where the opening 22A is closed. The cover C has an arm holding portion C2 on one side thereof. The arm holding portion C2 has an elongated hole C3 into which a cylindrical protrusion 156 of an arm 152, which will be described later, is inserted.

[0046] The drum cartridge 40 has a photosensitive drum 41 rotatably supported by a drum frame F1. The drum cartridge 40 also has a drum groove 42 extending in a first direction at the bottom of the drum frame F1. The drum groove 42 is guided by a drum guide protrusion 133, which will be described later.

[0047] In the developer cartridge 50, a developer roller 51 is rotatably supported by a developer frame F2. The developer cartridge 50 also has a developer groove 52 extending in the first direction at the bottom of the developer frame F2. The developer groove 52 is guided by a developer guide protrusion 134, which will be described later. The vertical size of the developing cartridge 50 is smaller than the vertical size of the drum cartridge 40. More specifically, the developing cartridge 50 has a size such that the developing roller 51 is located lower than the photosensitive drum 41 when the drum cartridge 40 and the developing cartridge 50 are attached to the main body housing 2.

[0048] The main body housing 2 includes a movable cam 110, a first lift 130, and a second lift 140 (see FIG. 4). The movable cam 110 is located below the drum cartridge 40 and the developing cartridge 50 when the drum cartridge 40 and the developing cartridge 50 are attached to the main body casing 2 . The movable cam 110 is a plate-shaped member. The movable cam 110 is movable in a first direction in association with the movement of the cover C from the open position to the closed position. In detail, the movable cam 110 is movable in the first direction via the arm 152 in conjunction with the opening and closing of the cover C. 3, the movable cam 110 has an upper surface 111 and a cylindrical protrusion 112 located on a side surface of the movable cam 110. The movable cam 110 slides on the upper surface of the guide portion 22B of the main body housing 2 (see FIG. 5).

[0049] As shown in FIG. 2, the arm 152 has one end 152A and the other end 152B. One end 152A of the arm 152 has a through hole 154 that rotatably supports the cylindrical projection 112 of the moving cam 110. The other end 152B of the arm 152 has a cylindrical projection 156. The cylindrical projection 156 is inserted into the elongated hole C3 of the arm holding portion C2.

[0050] 3, the moving cam 110 includes a set of drum spacing surfaces 114 spaced apart in a first direction, a set of drum inclined surfaces 116, and a set of drum contact surfaces 118. The set of drum spacing surfaces 114, the set of drum inclined surfaces 116, and the set of drum contact surfaces 118 are located on an upper surface 111 of the moving cam 110. The set of drum spacing surfaces 114 includes a first drum spacing surface 114A that is closer to the opening 22A and a second drum spacing surface 114B that is located farther from the opening 22A than the first drum spacing surface 114A. The first drum spacing surface 114A and the second drum spacing surface 114B extend in a first direction. The second drum spacing surface 114B is located away from the first drum spacing surface 114A in the first direction. The set of inclined drum surfaces 116 includes a first inclined drum surface 116A that is closer to the opening 22A, and a second inclined drum surface 116B that is located farther from the opening 22A than the first inclined drum surface 116A. The first inclined drum surface 116A extends from the first drum separation surface 114A toward the intermediate transfer belt 63. The first inclined drum surface 116A is inclined with respect to the first direction. The second inclined drum surface 116B is located away from the first inclined drum surface 116A in the first direction. The second inclined drum surface 116B extends from the second drum separation surface 114B toward the intermediate transfer belt 63. The second inclined drum surface 116B is also inclined with respect to the first direction. The first drum inclined surface 116A is located between the first drum separation surface 114A and a first drum contact surface 118A (described later) in the first direction. Similarly, the second drum inclined surface 116B is located between the second drum separation surface 114B and a second drum contact surface 118B (described later) in the first direction. A connection portion 115A between the first drum separation surface 114A and the first drum inclined surface 116A is formed as a curved surface, so that a first drum contact portion 135A (described later) can move smoothly between the first drum separation surface 114A and the first drum inclined surface 116A. Similarly, a connection portion 115B between the second drum separation surface 114B and the second drum inclined surface 116B is formed as a curved surface, so that a second drum contact portion 135B (described later) can move smoothly between the second drum separation surface 114B and the second drum inclined surface 116B. The set of drum contact surfaces 118 includes a first drum contact surface 118A that is close to the opening 22A, and a second drum contact surface 118B that is located farther from the opening 22A than the first drum contact surface 118A. The first drum contact surface 118A extends in the first direction from the first drum inclined surface 116A. The first drum contact surface 118A is closer to the intermediate transfer belt 63 in the vertical direction than the first drum separation surface 114A. The second drum contact surface 118B is located farther from the first drum contact surface 118A in the first direction. The second drum contact surface 118B extends in the first direction from the second drum inclined surface 116B. Also, the second drum contact surface 118B is closer to the intermediate transfer belt 63 in the vertical direction than the second drum separation surface 114B. A connection portion 117A between the first inclined drum surface 116A and the first drum contact surface 118A is formed as a curved surface, so that a first drum contact portion 135A (described later) can move smoothly between the first drum inclined drum surface 116A and the first drum contact surface 118A. Similarly, a connection portion 117B between the second inclined drum surface 116B and the second drum contact surface 118B is formed as a curved surface, so that a second drum contact portion 135B (described later) can move smoothly between the second inclined drum surface 116B and the second drum contact surface 118B.

[0051] The movable cam 110 also includes a set of developer separating surfaces 124 spaced apart in the first direction, a set of developer inclined surfaces 126, and a set of developer contact surfaces 128. The set of developer separating surfaces 124, the set of developer inclined surfaces 126, and the set of developer contact surfaces 128 are located on an upper surface 111 of the movable cam 110. The set of developer spacing surfaces 124 corresponds to the set of drum spacing surfaces 114. The set of developer spacing surfaces 124 is formed at a lower position than the set of drum spacing surfaces 114. The set of developing inclined surfaces 126 corresponds to the set of drum inclined surfaces 116. The set of developing inclined surfaces 126 is formed at a lower position than the set of drum inclined surfaces 116. A set of developer contact surfaces 128 corresponds to a set of drum contact surfaces 118 . The set of developer separating surfaces 124, the set of developer inclined surfaces 126, and the set of developer contact surfaces 128 are each located at four positions spaced apart in the second direction.

[0052] The set of development spacing surfaces 124 includes a first development spacing surface 124A that is closer to the opening 22A and a second development spacing surface 124B that is located farther from the opening 22A than the first development spacing surface 124A. The first development spacing surface 124A and the second development spacing surface 124B extend in a first direction. The second development spacing surface 124B is located away from the first development spacing surface 124A in the first direction. The set of developing inclined surfaces 126 includes a first developing inclined surface 126A close to the opening 22A and a second developing inclined surface 126B located farther from the opening 22A than the first developing inclined surface 126A. The first developing inclined surface 126A extends from the first developing separation surface 124A toward the intermediate transfer belt 63. The first developing inclined surface 126A is inclined with respect to the first direction. The second developing inclined surface 126B is located away from the first developing inclined surface 126A in the first direction. The second developing inclined surface 126B extends from the second developing separation surface 124B toward the intermediate transfer belt 63. The second developing inclined surface 126B is also inclined with respect to the first direction. The first developer inclined surface 126A is located between the first developer separation surface 124A and a first developer contact surface 128A (described later) in the first direction. Similarly, the second developer inclined surface 126B is located between the second developer separation surface 124B and a second developer contact surface 128B (described later) in the first direction. The set of developer contact surfaces 128 includes a first developer contact surface 128A that is close to the opening 22A, and a second developer contact surface 128B that is located farther from the opening 22A than the first developer contact surface 128A. The first developer contact surface 128A extends in the first direction from the first developer inclined surface 126A. The first developer contact surface 128A is closer to the intermediate transfer belt 63 in the vertical direction than the first developer separation surface 124A. The second developer contact surface 128B is located farther from the first developer contact surface 128A in the first direction. The second developer contact surface 128B extends in the first direction from the second developer inclined surface 126B. Also, the second developer contact surface 128B is closer to the intermediate transfer belt 63 in the vertical direction than the second developer separation surface 124B. The first developer contact surface 128A is flush with the first drum contact surface 118A, and the second developer contact surface 128B is flush with the second drum contact surface 118B. The connection portion between the developer separating surface 124 and the developer inclined surface 126 and the connection portion between the developer inclined surface 126 and the developer contact surface 128 may be formed into a curved surface.

[0053] As shown in FIG. 4, the first lift 130 is a member that engages with the moving cam 110 to move the drum cartridge 40 upward. The first lift 130 has an upper surface 131 and a lower surface 132. Four drum guide protrusions 133 and four developing guide protrusions 134 are located on the upper surface 131 of the first lift 130. The first lift 130 also includes a first drum contact portion 135A and a second drum contact portion 135B that contact the upper surface 111 of the moving cam 110. The second drum contact portion 135B is located away from the first drum contact portion 135A in the first direction. More specifically, the distance between the first drum contact portion 135A and the second drum contact portion 135B in the first direction is, for example, the same as the distance between the first drum inclined surface 116A and the second drum inclined surface 116B in the first direction. Each drum guide protrusion 133 extends in a first direction and serves to guide the drum cartridge 40. Each of the developer guide protrusions 134 extends in the first direction and serves to guide the developer cartridge 50. The height of each of the developer guide protrusions 134 in the up-down direction is lower than the height of each of the drum guide protrusions 133 in the up-down direction. Each of the development guide projections 134 has a guide hole 136. The guide hole 136 extends in the first direction and is a through hole for inserting the second lift 140. As shown in FIG. 4B, the guide hole 136 includes a first portion 136A and a second portion 136B. The first portion 136A is an opening that vertically passes through the development guide projection 134. The second portion 136B is an opening that communicates with the first portion 136A and vertically passes through the first drum contact portion 135A and the second drum contact portion 135B. The first lift 130 has a support surface 137 inside the guide hole 136. The support surface 137 functions as a retainer for the second lift 140 inserted into the guide hole 136, As shown in FIG. 5(b), the first lift 130, the movable cam 110 and the guide portion 22B have an opening through which the laser light from the exposure device SU passes.

[0054] The second lift 140 is a member that engages with the moving cam 110 to move the developing cartridge 50 upward. The second lift 140 is inserted into the guide hole 136. The second lift 140 includes a main body portion 141 extending in the first direction, and a first developing contact portion 142 and a second developing contact portion 144 extending downward from the main body portion 141. The main body portion 141 is supported by the support surface 137 during assembly. The first developing contact portion 142 and the second developing contact portion 144 contact the upper surface 111 of the moving cam 110 through the second portion 136B of the guide hole 136. The second developing contact portion 144 is located away from the first developing contact portion 142 in the first direction. The second lift 140 is movable up and down within the guide hole 136. The second lift 140 has lower ends of the first developing contact portion 142 and the second developing contact portion 144 protruding downward from the lower ends of the first drum contact portion 135A and the second drum contact portion 135B (see FIG. 5).

[0055] 2 and 5 to 7, a method for mounting the drum cartridge 40 and the developing cartridge 50 and a method for positioning the developing roller 51 and the photosensitive drum 41 will be described. 2, with the cover C in the open position to expose the opening 22A, the drum cartridge 40 and the developing cartridge 50 are attached to the main body housing 2. The drum cartridge 40 is inserted in the first direction along the upper surface 131 of the first lift 130 with the drum groove 42 fitted in the drum guide protrusion 133 of the first lift 130. Similarly, the developing cartridge 50 is inserted in the first direction along the upper surface 131 of the first lift 130 with the developing groove 52 fitted in the developing guide protrusion 134 of the first lift 130.

[0056] As shown in FIG. 5, when the cover C is in the open position, the moving cam 110 is in the first position. More specifically, when the moving cam 110 is located at the first position, the first drum contact portion 135A contacts the first drum separation surface 114A, and the second drum contact portion 135B contacts the second drum separation surface 114B. At this time, the first lift 130 is in the lowered position, and the photosensitive drum 41 of the drum cartridge 40 is separated from the intermediate transfer belt 63. Also, when the moving cam 110 is located at the first position, the first developer contact portion 142 contacts the first developer separation surface 124A, and the second developer contact portion 144 contacts the second developer separation surface 124B. At this time, since the second lift 140 does not protrude from the upper surface of the first lift 130, the developing roller 51 of the developing cartridge 50 is separated from the photosensitive drum 41. That is, when the cover C is in the open position, the movable cam 110 is in the first position, the photosensitive drum 41 is separated from the intermediate transfer belt 63, and the developing roller 51 is separated from the photosensitive drum 41.

[0057] As shown in FIG. 6, while the cover C moves from the open position to the closed position, the moving cam 110 is located at the second position. More specifically, when the cover C is moved from the open position to the closed position, the arm 152 moves the moving cam 110 in the first direction so as to move away from the opening 22A. Then, while the moving cam 110 moves from the first position to the second position, the first drum contact portion 135A contacts the first drum inclined surface 116A, and the second drum contact portion 135B contacts the second drum inclined surface 116B. As a result, the first lift 130 rises toward the intermediate transfer belt 63. Also, while the moving cam 110 moves from the first position to the second position, the first development contact portion 142 contacts the first development inclined surface 126A, and the second development contact portion 144 contacts the second development inclined surface 126B. As a result, the second lift 140 rises toward the intermediate transfer belt 63 together with the first lift 130.

[0058] When the cover C moves further toward the closed position, the moving cam 110 moves further in the first direction and is located at the second position. When the movable cam 110 is located at the second position, the first drum contact portion 135A contacts the first drum contact surface 118A, and the second drum contact portion 135B contacts the second drum contact surface 118B. At this time, the first lift 130 is in the raised position, and the photosensitive drum 41 of the drum cartridge 40 supported by the first lift 130 contacts the intermediate transfer belt 63. Also, when the moving cam 110 is located at the second position, the first developing contact portion 142 remains in contact with the first developing inclined surface 126A, and the second developing contact portion 144 remains in contact with the second developing inclined surface 126B. In other words, while the moving cam 110 moves from the first position to the third position, the first developing contact portion 142 comes in contact with the first developing inclined surface 126A, and the second developing contact portion 144 comes in contact with the second developing inclined surface 126B. At this time, since the second lift 140 does not protrude from the upper surface of the first lift 130, the developing roller 51 of the developing cartridge 50 remains separated from the photosensitive drum 41. That is, when the movable cam 110 is located at the second position, the photosensitive drum 41 is in contact with the intermediate transfer belt 63 and the developing roller 51 is separated from the photosensitive drum 41 .

[0059] As shown in FIG. 7, when the cover C is in the closed position, the moving cam 110 is in the third position. More specifically, when the moving cam 110 is located at the third position, the first drum contact portion 135A contacts the first drum contact surface 118A, and the second drum contact portion 135B contacts the second drum contact surface 118B. At this time, the first lift 130 is at the raised position, and the photosensitive drum 41 of the drum cartridge 40 supported by the first lift 130 remains in contact with the intermediate transfer belt 63. Also, when the moving cam 110 is located at the third position, the first developer contact portion 142 contacts the first developer contact surface 128A, and the second developer contact portion 144 contacts the second developer contact surface 128B. At this time, the second lift 140 protrudes upward from the guide hole 136, and the developer cartridge 50 is pressed by the second lift 140 and rises relative to the drum cartridge 40. Then, the developer roller 51 contacts the photosensitive drum 41. That is, when the movable cam 110 is located at the third position, the photosensitive drum 41 comes into contact with the intermediate transfer belt 63 , and the developing roller 51 comes into contact with the photosensitive drum 41 .

[0060] 3(b), in the movement direction in which the movable cam 110 moves from the first position to the third position, the downstream end of the first drum contact surface 118A is located downstream of the downstream end of the first developer contact surface 128A. Similarly, in the movement direction in which the movable cam 110 moves from the first position to the third position, the downstream end of the second drum contact surface 118B is located downstream of the downstream end of the second developer contact surface 128B.

[0061] According to this configuration, the first drum contact portion 135A and the second drum contact portion 135B first ride up onto the first drum contact surface 118A and the second drum contact surface 118B, and then the first developer contact portion 142 and the second developer contact portion 144 ride up onto the first developer contact surface 128A and the second developer contact surface 128B. Therefore, the photosensitive drum 41 comes into contact with the intermediate transfer belt 63 before the developing roller 51 comes into contact with the photosensitive drum 41. In addition, by changing the distance between the downstream end of the first drum contact surface 118A and the downstream end of the first developer contact surface 128A, and the distance between the downstream end of the second drum contact surface 118B and the downstream end of the second developer contact surface 128B, it is possible to change the timing at which the developing roller 51 and the photosensitive drum 41 come into contact after the photosensitive drum 41 and the intermediate transfer belt 63 come into contact.

[0062] As described above, the following effects can be obtained in this embodiment. Contact between the intermediate transfer belt 63 and the photosensitive drum 41 due to movement of the drum cartridge 40 relative to the intermediate transfer belt 63, and contact between the photosensitive drum 41 and the developing roller 51 due to movement of the developing cartridge 50 relative to the drum cartridge 40 can be achieved by a single action by the user positioning the cover C from the open position to the closed position, without using a motor.

[0063] When the movable cam 110 moves in conjunction with the opening and closing of the cover C, the first drum contact portion 135A of the first lift 130 comes into contact with the first drum separation surface 114A, the first drum inclined surface 116A or the first drum contact surface 118A, thereby changing the height position of the first lift 130 and allowing the drum cartridge 40 to be positioned at a predetermined position.

[0064] When the movable cam 110 moves in conjunction with the opening and closing of the cover C, the first developer contact portion 142 of the second lift 140 comes into contact with the first developer separation surface 124A, the first developer inclined surface 126A or the first developer contact surface 128A, thereby changing the height position of the second lift 140 and positioning the developer cartridge 50 at a predetermined position.

[0065] The first lift 130 has two drum contact portions 135A, 135B, the second lift has two developer contact portions 142, 144, and the movable cam 110 presses the two drum contact portions 135A, 135B and the two developer contact portions 142, 144, so that the drum cartridge and developer cartridge can be stably positioned.

[0066] Since the developing guide protrusion 134 has a guide hole 136 and the second lift 140 is movable within the guide hole 136, the drum cartridge 40 and the developing cartridge 50 can be moved relative to the intermediate transfer belt 63 by the first lift 130, and after the positioning of the photosensitive drum 41 relative to the intermediate transfer belt 63 is completed, the developing cartridge 50 can be moved relative to the drum cartridge 40 by the second lift 140, and the developing roller 51 can be positioned relative to the photosensitive drum 41.

[0067] Although the embodiment of the present disclosure has been described above, the present disclosure is not limited to the above-described embodiment. The specific configuration can be appropriately changed without departing from the spirit of the present disclosure.

[0068] In the above-described embodiment, in conjunction with the closing operation of the cover, the first lift 130 lifts the drum cartridge 40 and the developing cartridge 50 toward the intermediate transfer belt 63, and the second lift 140 further lifts the developing cartridge 50, but the present disclosure is not limited to such a configuration. For example, a drum lift that engages with the upper surface 111 of the movable cam 110 to move the drum cartridge 40 upward, and a developer lift that engages with the upper surface 111 of the movable cam 110 to move the developer cartridge 50 upward, may be configured to be able to move independently and separately. In such a configuration, the drum guide protrusion may be located on the upper surface of the drum lift, and the developer guide protrusion may be located on the upper surface of the developer lift.

[0069] In the above-described embodiment, the first lift 130 has the drum guide protrusion 133 and the developing guide protrusion 134, the drum cartridge 40 has the drum groove 42, and the developing cartridge 50 has the developing groove 52, but the present disclosure is not limited to such a configuration. For example, a drum guide groove may be used instead of the drum guide protrusion 133, and a drum protrusion may be used instead of the drum groove 42. Similarly, a developing guide groove may be used instead of the developing guide protrusion 134, and a developing protrusion may be used instead of the developing groove 52. Furthermore, these may be combined in any desired manner.

[0070] In the above-described embodiment, the moving cam 110 has a set (two) each of the drum separation surface 114, the drum inclined surface 116, the drum contact surface 118, the developer separation surface 124, the developer inclined surface 126, and the developer contact surface 128, the first lift 130 has a first drum contact portion 135A and a second drum contact portion 135B, and the second lift 140 has a first developer contact portion 142 and a second developer contact portion 144, but the present disclosure is not limited to such a configuration and may have any number. For example, the moving cam 110 may have one each of a drum separation surface 114, a drum inclined surface 116, a drum contact surface 118, a developer separation surface 124, a developer inclined surface 126, and a developer contact surface 128, the first lift 130 may have only one drum contact portion, and the second lift 140 may have only one developer contact portion. Moreover, the movable cam 110 may be configured without the development separation surface.

[0071] In the above embodiment, the present disclosure is applied to a color printer 1, but the present disclosure is not limited to this and may be applied to other image forming devices, such as monochrome printers, copiers, and multifunction devices.

[0072] The elements described in the above-mentioned embodiment and modified examples may be implemented in any combination. [Explanation of symbols]

[0073] 1. Color printer 2 Main unit 22A opening C-Cover 40 Drum Cartridge 41 Photosensitive drum 50 Developing Cartridge 51 Developing roller 63 Intermediate transfer belt 110 Moving Cam

Claims

[Claim 1] a main body housing having an opening; a cover movable between an open position for opening the opening and a closed position for closing the opening; a drum unit having a photosensitive drum rotatable about a first axis extending in a first direction; a developing unit having a developing roller rotatable about a second axis extending in the first direction; an intermediate transfer belt located above the drum unit and the developing unit, In conjunction with the movement of the cover from the open position to the closed position, the photosensitive drum, the intermediate transfer belt, and the developing roller are a first state in which the photosensitive drum is separated from the intermediate transfer belt and the developing roller is separated from the photosensitive drum; a second state in which the photosensitive drum is in contact with the intermediate transfer belt and the developing roller is separated from the photosensitive drum; an image forming apparatus, characterized in that the photosensitive drum is in contact with the intermediate transfer belt, and the developing roller is in a third state in which the developing roller is closer to the photosensitive drum than in the first state.

Images