Image forming device

Abstract

To provide an image forming apparatus that prevents a body-side coupling from contacting a joint cam without involving an increase in the size of an apparatus body, and thereby can form a high-quality image.SOLUTION: An image forming apparatus 1 comprises: a process cartridge 50 that includes a cartridge-side coupling 521; a body-side coupling 71 that has a joint 711 and a flange 712; and a joint cam 74 that has an opening 741 composed of a first opening 741a and a second opening 741b. The distance D1 between a first surface 741A and a second surface 741B of the second opening 741b is smaller than the added dimension (r+R) of the radius r of the joint 711 and the radius R of the flange 712 over the entire area of the first surface 741A and the second surface 741B.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Conventionally, there has been known an image forming apparatus in which a developer cartridge is detachably mounted in an apparatus main body having a drive member, a cartridge-side coupling is provided on the developer cartridge for transmitting a drive force to a member inside the developer cartridge, a main body-side coupling that is movable between a connected position where it is connected to the cartridge-side coupling and a separated position where it is separated from the cartridge-side coupling, a joint cam that is movable to a first position where it places the main body-side coupling in the separated position and a second position where it places the main body-side coupling in the connected position, and a rotating member that transmits the drive force to the drive member (see, for example, Patent Document 1).

[0003] The main body side coupling has a joint engageable with the cartridge side coupling and a flange provided on the outer periphery of the joint. The joint cam has an opening consisting of a first opening in which the joint of the main body side coupling located in the separated position is disposed, and a second opening that is continuous with the first opening and in which the joint of the main body side coupling located in the connected position is disposed.

[0004] The first opening is formed in the shape of an elongated hole with a width dimension approximately the same as the outer diameter of the joint, and the second opening is formed in a circular shape with an inner diameter larger than the outer diameter of the joint. An inclined rib is provided on the periphery of the first opening, and when the joint cam moves between the first position and the second position, the body-side coupling is configured to move between the connected position and the separated position by the flange abutting against the inclined rib.

[0005] The developing cartridge also includes a photosensitive drum and a developing roller connected to the cartridge side coupling, and the developing roller is configured to be movable to a contact position where it contacts the photosensitive drum and a separated position where it is separated from the photosensitive drum when the main body side coupling is positioned in the connected position. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-177840 Summary of the Invention [Problem to be solved by the invention]

[0007] Here, for example, when the joint cam is moved to the second position, the joint cam may stop at a position slightly shifted from the second position, for example, a position slightly shifted toward the first position from the predetermined stop position. In such a case, although the main body side coupling has been moved to the connected position, it may interfere with the joint cam when, for example, the developing roller is separated from the photosensitive drum or an unexpected external impact is applied, which may induce poor rotation or vibration of the cartridge side coupling and result in poor image quality.

[0008] Therefore, extending the second opening toward the first opening is considered as a measure to prevent the main body coupling from contacting the joint cam even when the joint cam stops at a position slightly shifted from the second position. However, in the case of a conventional circular second opening, extending the second opening toward the first opening requires increasing the inner diameter and widening the entire opening. Widening the entire opening too much could cause part of the main body coupling to pass through the second opening and fall out. Furthermore, the outer diameter of the joint cam would increase, which could lead to an increase in the size of the entire device.

[0009] Therefore, the present invention aims to provide an image forming apparatus that can form high-quality images by preventing the main body coupling from coming into contact with the joint cam without increasing the size of the apparatus main body. [Means for solving the problem]

[0010] The image forming apparatus that solves the above problem has the following features.

[0011] That is, the image forming apparatus includes a cartridge having a cartridge-side coupling that transmits a driving force to a member inside the cartridge; a main body-side coupling that is provided axially reciprocally relative to the cartridge-side coupling, is movable between a connected position where it is connected to the cartridge-side coupling and a separated position separated from the cartridge-side coupling in the axial direction, and has a joint that is engageable with the cartridge-side coupling and a flange that is provided coaxially with the joint; and is movable between a first position where the main body-side coupling is disposed at the separated position and a second position where the main body-side coupling is disposed at the connected position, and a joint cam having an opening consisting of a first opening in which the joint of the main body side coupling located at the connection position is disposed, and a second opening in which the joint of the main body side coupling located at the connection position is disposed and which is continuous with the first opening, wherein the second opening has a first surface extending in the movement direction of the joint cam and a second surface facing the first surface in a direction perpendicular to the movement direction and extending in the movement direction, and the distance between the first surface and the second surface in the direction perpendicular to the movement direction is smaller than the sum of the radius r of the joint and the radius R of the flange (r+R) over the entire area of ​​the first surface and the second surface.

[0012] This allows the second opening to be extended toward the first opening without widening the entire opening, and prevents the main body side coupling from coming into contact with the joint cam without increasing the size of the entire device, thereby preventing the occurrence of poor image quality.It also prevents the main body side coupling from passing through the second opening and falling off.

[0013] The first surface and the second surface of the second opening are formed in a straight line extending in the movement direction.

[0014] This makes it possible to more reliably extend the second opening toward the first opening.

[0015] Further, the joint cam has a plurality of the openings arranged adjacent to each other along the movement direction, and the openings have inclined ribs that protrude from the periphery of the first opening in the axial direction of the main body side coupling and abut against the flange when the joint cam moves, thereby moving the main body side coupling between the connected position and the separated position, and the inclined ribs have a first inclined rib located on one side of the periphery of the first opening in a direction perpendicular to the movement direction and extending in the movement direction, and a second inclined rib located on the other side of the periphery of the first opening in a direction perpendicular to the movement direction and extending in the movement direction, and a gap is formed between the end of the first inclined rib on the side adjacent to the second opening of the other opening, and the end of the second inclined rib on the side adjacent to the second opening of the other opening.

[0016] This makes it possible to shorten the distance between the axes of the multiple main body side couplings provided corresponding to the multiple openings, thereby making it possible to make the entire device more compact.

[0017] Furthermore, the first surface and the second surface of the second opening are arranged opposite each other in the vertical direction, the second surface is positioned lower than the first surface, and the second surface is formed shorter than the first surface in the movement direction.

[0018] This makes it possible to ensure the space required to avoid interference between the joint and the joint cam on the first surface side when the main body coupling located in the connected position is tilted obliquely upward toward the end of the first surface located above on the opposite side from the first opening side. Also, it is possible to reduce the space on the second surface side, where interference does not need to be considered, and it is possible to make the entire device more compact.

[0019] The cartridge is a developing cartridge that includes the photosensitive drum and a developing roller that is connected to the cartridge side coupling and is movable between a contact position where it contacts the photosensitive drum and a separation position where it is separated from the photosensitive drum when the main body side coupling is positioned at the connection position, and the second opening has a retraction surface that does not interfere with the joint of the main body side coupling when the developing roller moves to the separation position.

[0020] This makes it possible to further prevent the joint of the main body side coupling from interfering with the second opening, even when the main body side coupling moves in accordance with the movement of the developing roller to the separated position, by the retraction surface.

[0021] Furthermore, the joint arranged in the second opening is movable between a third position when the developing roller is located at the abutment position and a fourth position when the developing roller is located at the separation position, and the fourth position is located closer to the first surface in a direction perpendicular to the movement direction and opposite the first opening side in the movement direction than the third position, and an end portion of the first surface opposite the first opening side and an end portion of the second surface opposite the first opening side are connected by a third surface having a first arcuate surface along the outer peripheral surface of the joint located at the third position, a second arcuate surface along the outer peripheral surface of the joint located at the fourth position, and a straight surface located between the first arcuate surface and the second arcuate surface and extending tangentially to the first arcuate surface and the second arcuate surface.

[0022] This allows the second opening to have a more appropriate shape that can avoid interference between the joint of the main body side coupling and the second opening when separating the developing roller from the photosensitive drum.

[0023] Furthermore, the first opening has a fourth surface formed in a straight line extending in the movement direction, and a fifth surface opposite the fourth surface in a direction perpendicular to the movement direction and formed in a straight line extending in the movement direction, the opening has a first connection surface connecting the first surface and the fourth surface, and a second connection surface connecting the second surface and the fifth surface, the distance between the first surface and the second surface in a direction perpendicular to the movement direction being greater than the distance between the fourth surface and the fifth surface in a direction perpendicular to the movement direction, and the first connection surface and the second connection surface are formed by inclined surfaces inclined at an obtuse angle with respect to the movement direction.

[0024] This allows the first connecting surface and the second connecting surface to allow the main body side coupling to move more smoothly between the first opening and the second opening. [Effects of the Invention]

[0025] According to the present invention, it is possible to prevent the main body side coupling from coming into contact with the joint cam without increasing the size of the apparatus main body, and to form high quality images. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a central cross-sectional view showing the image forming apparatus. [Figure 2] FIG. 2 is a perspective view showing the image forming apparatus when the top cover is in a closed position. [Figure 3] FIG. 2 is a perspective view showing the image forming apparatus when the top cover is in the open position. [Figure 4] FIG. [Figure 5]1A is a plan sectional view showing the main body side coupling in the separated position, and FIG. 1B is a plan sectional view showing the main body side coupling in the connected position. [Figure 6] FIG. 2 is a side view showing the left side of the device main body. [Figure 7] FIG. 2(a) is a perspective view showing a joint cam, and FIG. 2(b) is a side view showing the joint cam. [Figure 8] FIG. 10 is a side view showing the opening of the joint cam. [Figure 9] FIG. 10 is a diagram showing the radius r of the joint and the radius R of the flange. [Figure 10] 1(a) is a side view showing the joint when placed in the second opening and in a third position, and FIG. 1(b) is a side view showing the joint when placed in the second opening and in a fourth position. [Figure 11] FIG. 2 is a side view showing the rear part on the left side of the apparatus main body when the top cover is in the closed position. [Figure 12] FIG. 2 is a side view showing the rear part on the left side of the apparatus main body when the top cover is in the open position. DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0028] [Image forming device] The image forming apparatus 1 shown in FIGS. 1 to 3 is one embodiment of the image forming apparatus according to the present invention, and is a color laser printer that forms a multi-color image on a sheet S by electrophotography.

[0029] In the following description, the right side in Fig. 1 is defined as the front side of the image forming apparatus 1, the left side in Fig. 1 is defined as the rear side of the image forming apparatus 1, the front side of the paper in Fig. 1 is defined as the left side of the image forming apparatus 1, and the back side of the paper in Fig. 1 is defined as the right side of the image forming apparatus 1. In addition, the upper and lower sides in Fig. 1 are defined as the upper and lower sides of the image forming apparatus 1, respectively.

[0030] The image forming apparatus 1 includes a device main body 2, a paper feed unit 3 having a paper feed tray 10 that supports sheets S and a sheet transport unit 30 that transports sheets S, an image forming unit 5 that forms a toner image on the sheets S transported by the paper feed unit 3, a fixing device 6 that fixes the toner image on the sheets S, and a motor 4.

[0031] The device body 2 is formed in a substantially rectangular parallelepiped shape and houses a paper feed unit 3, an image forming unit 5, a fixing unit 6, and a motor 4. An opening 2A is formed on the top surface of the device body 2. The image forming device 1 has a top cover 21 that can open and close the opening 2A of the device body 2.

[0032] The top cover 21 is supported on the device body 2 so as to be rotatable about a rotation shaft 21a at the rear end. By rotating about the rotation shaft 21a, the top cover 21 can move between a closed position (position shown in FIG. 2) in which the opening 2A is closed and an open position (position shown in FIG. 3) in which the opening 2A is open. The top cover 21 is formed with a paper output tray 21b that slopes downward from the front to the rear.

[0033] As shown in Fig. 3, a damper 22 is interposed between the top cover 21 and the apparatus main body 2. The dampers 22 are provided at the left and right ends of the image forming apparatus 1, respectively. The damper 22 has a cylinder 221 and a piston 222. The cylinder 221 is supported by the apparatus main body 2 so as to be rotatable about a rotation fulcrum 221a. The piston 222 is configured to be extendable and retractable relative to the cylinder 221, and is supported by the top cover 21 so as to be rotatable about a rotation fulcrum 222a.

[0034] By interposing a damper 22 between the top cover 21 and the device main body 2, it is possible to reduce the force required to open and close the top cover 21 and to prevent the top cover 21 from closing suddenly due to its own weight.

[0035] The paper feed unit 3 is disposed at the bottom of the device body 2, and transports the sheets S supported on the paper feed tray 10 to the image forming unit 5 by the sheet transport unit 30. The paper feed tray 10 is configured to be slidable in the front-to-rear direction, and is configured to be movable between a storage position where it is stored in the device body 2, and a separation position where it is pulled out forward from the storage position.

[0036] The sheet conveying section 30 includes a paper feed roller 32, a separation roller 33, a separation pad 33a, a conveying roller pair 34, and a registration roller pair 35. Within the device main body 2, a conveying path P for the sheet S is configured, which runs from the paper feed tray 10 to the paper discharge tray 21b via the image forming section 5.

[0037] The sheets S supported on the paper feed tray 10 are separated one by one by the paper feed roller 32, separation roller 33, and separation pad 33a and sent out to the conveying path P. The paper feed roller 32 is a roller that conveys the sheets S from the paper feed tray 10 toward the image forming unit 5. The separation roller 33 and separation pad 33a constitute a separating means that separates the sheets S supported on the paper feed tray 10 one by one.

[0038] The sheet S sent to the conveying path P is conveyed toward the image forming unit 5 by a pair of conveying rollers 34 and a pair of registration rollers 35. The pair of registration rollers 35 regulates the movement of the leading edge of the sheet S being conveyed, stops the sheet S temporarily, and then conveys the sheet S toward the image forming unit 5 at a predetermined timing.

[0039] The image forming unit 5 is disposed above the paper feeding unit 3, and includes four process cartridges 50 arranged side by side in the front-to-rear direction. The process cartridges 50 are an example of a cartridge. Each process cartridge 50 is provided corresponding to one of the colors: black, yellow, magenta, and cyan. The process cartridges 50 are detachably mounted in the apparatus main body 2. Each process cartridge 50 includes a photosensitive drum 51, a developing roller 52, a supply roller 53, and a charger 54. The process cartridge 50 is a developing cartridge that includes the photosensitive drum 51 and the developing roller 52.

[0040] The process cartridge 50 is mounted in the apparatus main body 2 with the axis X direction (see FIG. 5) of the developing roller 52 aligned in the left-right direction. The developing roller 52 is configured to be movable between a contact position where it contacts the photosensitive drum 51 and a spaced position where it is spaced from the photosensitive drum 51. The supply roller 53 supplies toner contained in the process cartridge 50 to the developing roller 52.

[0041] The device main body 2 has exposure heads 59 that expose the surfaces of the photosensitive drums 51. The exposure heads 59 are supported by the top cover 21. Four exposure heads 59 are provided, one for each photosensitive drum 51, and the exposure heads 59 are arranged side by side in the front-to-rear direction. The exposure heads 59 extend downward from the top cover 21 and have an exposure section 59a at their lower ends. The exposure section 59a is disposed close to and above the photosensitive drum 51 when the top cover 21 is closed. The exposure section 59a is configured as an LED array having a plurality of LED elements arranged side by side in the left-to-right direction.

[0042] A transfer belt 41 is disposed below the photosensitive drum 51, facing the photosensitive drum 51 across the transport path P. The transfer belt 41 is stretched between a drive roller 42 and a driven roller 43 disposed in front of the drive roller 42. The transfer belt 41, drive roller 42, and driven roller 43 constitute a belt device 40. A transfer roller 44 is disposed at a position facing each photosensitive drum 51 across the transfer belt 41.

[0043] In the image forming unit 5, the photosensitive drums 51, which have been uniformly charged by the chargers 54, are selectively exposed to light by the exposure heads 59. This exposure selectively removes charge from the surfaces of the photosensitive drums 51, and an electrostatic latent image is formed on the surfaces of the photosensitive drums 51.

[0044] The toner contained in the process cartridge 50 is positively charged between the supply roller 53 and the developing roller 52 and is carried on the surface of the developing roller 52. A developing bias is applied to the developing roller 52, and when the electrostatic latent image formed on the photosensitive drum 51 faces the developing roller 52, the potential difference between the electrostatic latent image and the developing roller 52 causes toner to be supplied from the developing roller 52 to the electrostatic latent image. As a result, a toner image is formed on the surface of the photosensitive drum 51.

[0045] When the sheet S transported toward the image forming unit 5 reaches the transfer belt 41, it is transported by the transfer belt 41 and passes sequentially between the transfer belt 41 and each photosensitive drum 51. Then, when the toner image on the surface of the photosensitive drum 51 faces the sheet S, it is transferred onto the sheet S by a transfer bias applied to the transfer roller 44.

[0046] In this embodiment, the transfer belt 41 is configured as a conveying belt that conveys the sheet S onto which the toner image is transferred, but it can also be configured as an intermediate transfer belt in which the toner image is transferred to the belt itself and the toner image transferred to the belt is further transferred to the sheet S.

[0047] The sheet S onto which the toner image has been transferred is transported to a fixing device 6. The fixing device 6 includes a heating roller 61 and a pressure roller 62 that is in pressure contact with the heating roller 61. The heating roller 61 is heated by a power source (not shown) that is provided in the apparatus main body 2. The toner image on the sheet S transported to the fixing device 6 is thermally fixed while the sheet S passes between the heating roller 61 and the pressure roller 62.

[0048] The sheet S on which the toner image has been thermally fixed is transported downstream in the transport direction from the fixing device 6, and further transported by the intermediate discharge roller pair 64 and the discharge roller pair 65 arranged downstream in the transport direction of the intermediate discharge roller pair 64, and then discharged onto the discharge tray 21b.

[0049] 4, the device body 2 includes a first body frame 24 and a second body frame 25 that are spaced apart from each other in the left-right direction. The first body frame 24 is located at the right end of the device body 2 and extends in the front-rear and up-down directions. The second body frame 25 is located at the left end of the device body 2 and extends in the front-rear and up-down directions.

[0050] The process cartridge 50 and the fixing unit 6 are disposed between the first body frame 24 and the second body frame 25. The first body frame 24 is disposed to the right of the process cartridge 50 and the fixing unit 6, and the second body frame 25 is disposed to the left of the process cartridge 50 and the fixing unit 6. The process cartridge 50 is detachably supported by the first body frame 24 and the second body frame 25.

[0051] [Cartridge side coupling] As shown in Figure 5, the process cartridge 50 has a cartridge-side coupling 521 connected to the left end of the developing roller 52. The cartridge-side coupling 521 is a coupling member that transmits driving force to the developing roller 52, which is a component inside the process cartridge 50. The developing roller 52 is connected to the cartridge-side coupling 521, and the developing roller 52 and the cartridge-side coupling 521 are arranged coaxially. The cartridge-side coupling 521 is located to the right of the second main body frame 25.

[0052] [Main body coupling] 5, the apparatus main body 2 has a main body side coupling 71, a drive gear 72, and a spring 73. The main body side coupling 71 is a coupling member for connecting to the cartridge side coupling 521 to transmit the driving force from the motor 4 to the developing roller 52. The main body side couplings 71 are provided corresponding to the four process cartridges 50 included in the image forming apparatus 1, and the four main body side couplings 71 are arranged side by side in the front-rear direction.

[0053] The main body side coupling 71 is disposed to the left of the second main body frame 25 and is supported by the second main body frame 25 so as to be movable in the left-right direction. The main body side coupling 71 has a joint 711 that can engage with the cartridge side coupling 521, and a flange 712 that is provided coaxially with the joint 711 and has a larger diameter than the joint 711.

[0054] The joint 711 is provided so as to be movable back and forth in the left-right direction relative to the cartridge-side coupling 521. The joint 711 is movable between a connected position (position shown in FIG. 5(b)) on the right where it is connected to the cartridge-side coupling 521, and a separated position (position shown in FIG. 5(a)) to the left of the connected position where it is separated from the cartridge-side coupling 521. The joint 711 is located at the connected position when the top cover 21 is in the closed position, and is located at the separated position when the top cover 21 is in the open position.

[0055] The second main body frame 25 has a communication hole 252 penetrating in the left-right direction at a position facing the cartridge side coupling 521 and the main body side coupling 71. When the main body side coupling 71 is in the connected position, the joint 711 protrudes from the left of the second main body frame 25 to the right of the second main body frame 25 through the communication hole 252 (see FIG. 5(b)). When the main body side coupling 71 is in the separated position, the main body side coupling 71 as a whole retracts to the left of the second main body frame 25 (see FIG. 5(a)).

[0056] The drive gear 72 is connected to the motor 4 and is configured to be rotatable integrally with the main body side coupling 71. When the main body side coupling 71 is in the connected position, the drive gear 72 is driven by the drive force from the motor 4, and the drive force is transmitted to the developing roller 52 through the joint 711 and the cartridge side coupling 521, which are connected to each other. On the other hand, when the main body side coupling 71 is in the separated position, the joint 711 and the cartridge side coupling 521 are separated, so that even if the drive gear 72 is driven by the drive force from the motor 4, the drive force is not transmitted to the developing roller 52.

[0057] The spring 730 is interposed between the flange 712 of the main body side coupling 71 and the drive gear 72, and biases the main body side coupling 71 to the right. The biasing force of the spring 70 enables the main body side coupling 71 to move from the separated position to the connected position.

[0058] The developing roller 52 can move between the contact position and the separated position with the main body side coupling 71 located at the connected position. When the developing roller 52 is located at the contact position, the main body side coupling 71 is connected to the cartridge side coupling 521 in such an orientation that the axial Y direction of the main body side coupling 71 and the joint 711 is parallel to the axial X direction of the developing roller 52.

[0059] On the other hand, when the developing roller 52 moves from the abutment position to the separated position, the main body side coupling 71 connected to the cartridge side coupling 521 moves while tilting in the direction of the axis X, following the movement of the cartridge side coupling 521 which moves together with the developing roller 52 (see Figure 10(b)).

[0060] [Joint Cam] 5 and 6, the device main body 2 has a joint cam 74 that is supported on the second main body frame 25 so as to be movable in the front-rear direction. The joint cam 74 is formed of a long plate-like member that extends along the front-rear direction. The front-rear direction is the direction in which the joint cam 74 moves.

[0061] The joint cam 74 can be positioned at a first position (position shown in FIG. 5(a)) where the main body side coupling 71 is placed in the separated position by moving forward, and can be positioned at a second position (position shown in FIG. 5(b)) where the main body side coupling 71 is placed in the connected position by moving rearward. In other words, the joint cam 74 can be moved between the first position where the main body side coupling 71 is placed in the separated position and the second position where the main body side coupling 71 is placed in the connected position.

[0062] 5 and 7, the joint cam 74 has an opening 741, an inclined rib 742, a rail 743, and a drive hole 744. The openings 741 and the inclined ribs 742 are provided corresponding to the four main body side couplings 71, and are arranged side by side at four locations along the front-rear direction. In this way, the joint cam 74 has a plurality of openings 741 arranged adjacent to one another along the movement direction.

[0063] Of the four openings 741, the opening 741 located most forward will be referred to as opening 741-1, the opening 741 located adjacent to and rear of opening 741-1 will be referred to as opening 741-2, the opening 741 located adjacent to and rear of opening 741-2 will be referred to as opening 741-3, and the opening 741 located adjacent to and rear of opening 741-3 will be referred to as opening 741-4, as appropriate.

[0064] The opening 741 penetrates in the left-right direction and is formed in a generally oval shape that is long in the front-rear direction. The opening 741 has a first opening 741a located at the rear and a second opening 741b formed continuously in front of the first opening 741a. The joint 711 of the main body side coupling 71 is inserted into the opening 741 from the left.

[0065] The inclined rib 742 protrudes from the periphery of the first opening 741a to the left in the axial Y direction of the main body side coupling 71. The inclined rib 742 has an inclined surface that protrudes to the left as it moves from the front to the rear. The flange 712 of the main body side coupling 71 can abut against the inclined rib 742.

[0066] When the joint cam 74 moves rearward and is in the second position, the joint 711 of the main body side coupling 71 is located at the second opening 741b of the opening 741. When the joint 711 is located at the second opening 741b, the flange 712 is not in contact with the inclined rib 742, and the main body side coupling 71 is biased rightward by the biasing force of the spring 73 and is positioned at the connected position.

[0067] When the joint cam 74, which is in the second position, moves forward, the flange 712 comes into contact with the inclined rib 742 and is pressed to the left by the inclined surface, causing the main body coupling 71 to move leftward from the connected position. When the joint cam 74 moves forward and the joint 711 is positioned at the first opening 741a of the opening 741, the main body coupling 71, which has moved to the left, is positioned at the separated position. In this way, when the joint cam 74 moves in the front-to-rear direction between the first position and the second position, the inclined rib 742 comes into contact with the flange 712, causing the main body coupling 71 to move between the connected position and the separated position.

[0068] The inclined rib 742 has a first inclined rib 742a that is located at the upper edge of the first opening 741a in the opening 741 and extends in the front-rear direction, and a second inclined rib 742b that is located at the lower edge of the first opening 741a and extends in the front-rear direction. The upper edge of the first opening 741a is an example of one side of the periphery of the first opening in a direction perpendicular to the movement direction of the joint cam 74. The lower edge of the first opening 741a is an example of the other side of the periphery of the first opening in a direction perpendicular to the movement direction of the joint cam 74.

[0069] A gap d is formed between the end of the first inclined rib 742a of the forward-most opening 741-1 on the side adjacent to the second opening 741b of the opening 741-2 adjacent to the opening 741-1, and the end of the second inclined rib 742b of the opening 741-1 on the side adjacent to the second opening 741b of the opening 741-2. The opening 741-1 is an example of one of the plurality of adjacent openings, and the opening 741-2 is an example of the other of the plurality of adjacent openings.

[0070] In this way, in the multiple openings 741-1, 741-2 arranged adjacent to each other, by providing a gap d between the first inclined rib 742a and the second inclined rib 742b in one opening 741-1, it is possible to prevent the first inclined rib 742a and the second inclined rib 742b in one opening 741-1 from interfering with the flange 712 of the main body side coupling 71 provided opposite the other opening 741-2. This makes it possible to shorten the inter-axial distance between the multiple main body side couplings 71 provided corresponding to the multiple openings 741, thereby making the entire device more compact.

[0071] A gap d is also formed between the first inclined rib 742a and the second inclined rib 742b in the opening 741-2, and between the first inclined rib 742a and the second inclined rib 742b in the opening 741-3.

[0072] The rail 743 is formed at the rear end of the joint cam 74 and has a groove shape that extends in the vertical direction. The drive hole 744 is a hole that penetrates in the left-right direction and extends in the vertical direction. The drive hole 744 is located in front of the rail 743 at the rear end of the joint cam 74. The upper end of the rail 743 is located lower than the upper end of the drive hole 744.

[0073] 8, the second opening 741b has a first surface 741A extending in the front-rear direction and a second surface 741B extending in the front-rear direction and facing the first surface 741A in the up-down direction. The up-down direction is an example of a direction perpendicular to the movement direction of the joint cam 74. The first surface 741A and the second surface 741B are disposed facing each other in the up-down direction, and the second surface 741 is positioned lower than the first surface 741A. The first surface 741A and the second surface 741B are each formed in a straight line extending in the front-rear direction.

[0074] In this way, the second opening 741b in which the main body side coupling 71 in the connected position is positioned has a first surface 741A and a second surface 741B extending in the front-to-rear direction, making it possible to extend the second opening 741b toward the first opening 741a without widening the entire opening.

[0075] Therefore, even if the joint cam 74 stops at a position slightly deviated from the second position, for example, it is possible to prevent the main body side coupling 71 from coming into contact with the joint cam 74 without increasing the size of the entire apparatus. This makes it possible to prevent the occurrence of poor image quality induced by poor rotation or vibration of the cartridge side coupling 521 due to contact between the joint cam 74 and the main body side coupling 71.

[0076] Furthermore, first surface 741A and second surface 741B are each formed in a straight line extending in the front-rear direction, which makes it possible to more reliably extend second opening 741b toward first opening 741a.

[0077] 8, the length of first surface 741A in the front-rear direction is L1, and the length of second surface 741B in the front-rear direction is L2. Length L2 of second surface 741B is shorter than length L1 of first surface 741A. In other words, second surface 741B is formed shorter in the front-rear direction than first surface 741A. The vertical distance between first surface 741A and second surface 741B is D1.

[0078] 9, the radius of the joint 711 of the main body side coupling 71 is r, and the radius of the flange 712 is R. The distance D1 in the up-down direction between the first surface 741A and the second surface 741B is set to be smaller than the sum of the radius r of the joint 711 and the radius R of the flange 712 (r+R) over the entire area of ​​the first surface 741A and the second surface 741B in the front-rear direction.

[0079] Therefore, even if the main body side coupling 71 moves while tilting in the axial direction X in response to the movement of the cartridge side coupling 521, for example, when separating the developing roller 52 from the photosensitive drum 51, it is possible to prevent a part of the main body side coupling 71 from passing through the second opening 741b and falling off (see the main body side coupling 71 indicated by the two-dot chain line in Figure 8, which is located at the second opening 741b of the opening 741-2).

[0080] That is, for example, it is possible to prevent a part of the main body side coupling 71 from passing through the second opening 741b and falling off, without inducing an expansion of the arrangement space inside the device main body 2, as would be the case if the diameter of the flange 712 of the main body side coupling 71 were set large, or without inducing interference between the main body side coupling 71 and the joint cam 74, as would be the case if the distance D1 between the first surface 741A and the second surface 741B at the second opening 741b were shortened more than necessary.

[0081] As shown in Figure 10, the joint 711 arranged in the second opening 741b of the opening 74 is movable between a third position (the position shown in Figure 10(a)) when the developing roller 52 is located in the abutment position, and a fourth position (the position shown in Figure 10(b)) when the developing roller 52 is located in the separated position.

[0082] The third position of the joint 711 is a position where the axial Y direction of the joint 711 is parallel to the axial X direction of the developing roller 52. The developing roller 52 moves diagonally upward and forward when moving from the contact position to the separated position, and the fourth position of the joint 711 is a position where the axial Y direction of the joint 711 is inclined diagonally upward and forward with respect to the axial X direction of the developing roller 52. In other words, the fourth position of the joint 711 is located closer to the first surface 741A in the up-down direction and on the opposite side from the first opening 741a in the front-rear direction than the third position.

[0083] The front end portion, which is the end portion of the first surface 741A opposite to the first opening 741a side, and the front end portion, which is the end portion of the second surface 741B opposite to the first opening side 741a, are connected by the third surface 741C.

[0084] As shown in Figures 8 and 10, the third surface 741C has a first arcuate surface 741C-1 along the outer peripheral surface 711A of the joint 711 located at the third position, a second arcuate surface 741C-2 along the outer peripheral surface 711B of the joint 711 located at the fourth position, and a straight surface 741C-3 located between the first arcuate surface 741C-1 and the second arcuate surface 741C-2 and extending in the tangent Z direction of the first arcuate surface 741C-1 and the second arcuate surface 741C-2.

[0085] The first arcuate surface 741C-1 is located at the bottom of the third surface 741C and is formed contiguous with the second surface 741B. The second arcuate surface 741C-2 is located at the top of the third surface 741C and is formed contiguous with the first surface 741A. The lower end of the linear surface 741C-3 is connected to the first arcuate surface 741C-1, and the upper end of the linear surface 741C-3 is connected to the second arcuate surface 741C-2. On the third surface 741C, the first arcuate surface 741C-1, the linear surface 741C-3, and the second arcuate surface 741C-2 are located in this order from bottom to top.

[0086] The shape of the second arc surface 741C-2 located at the front and upper end of the second opening 741b, which is the tilt direction of the joint 711, is formed to follow the outer peripheral surface 711B of the joint 711 located at the fourth position, thereby preventing interference between the joint 711 and the joint cam 74 when the joint 711 is located at the fourth position.

[0087] That is, the second arcuate surface 741C-2 of the second opening 741b is a retracted surface that retracts so as not to interfere with the joint 711 of the main body side coupling 71 when the developing roller 52 moves to the separated position. By using the second arcuate surface 741C-2 as the retracted surface in this way, even when the main body side coupling 71 moves in response to the movement of the developing roller 52 to the separated position, the retracted surface can further prevent the joint 711 of the main body side coupling 71 from interfering with the second opening 741b.

[0088] In addition, in the second opening 741b, the third surface 741C located on the front side is composed of a first arcuate surface 741C-1, a second arcuate surface 741C-2, and a straight surface 741C-3, so that the shape of the second opening 741b can be made more appropriate to avoid interference between the joint 711 of the main body side coupling 71 and the second opening 741b when separating the developing roller 52 from the photosensitive drum 51.

[0089] Furthermore, at the second opening 741b, the second surface 741B is formed shorter than the first surface 741A, and therefore, when the main body side coupling 71 located at the connected position is tilted obliquely upward toward the front end of the first surface 741A located above, on the side opposite to the first opening 741a, it is possible to ensure on the first surface 741A side the space necessary to avoid interference between the joint 711 and the joint cam 74. Furthermore, it is possible to reduce the space on the second surface 741B side, where interference does not need to be considered, and it is possible to make the entire device more compact.

[0090] 8, first opening 741a has fourth surface 741D formed in a straight line extending in the front-rear direction, and fifth surface 741E opposed to fourth surface 741D in the up-down direction and formed in a straight line extending in the front-rear direction. The distance in the up-down direction between fourth surface 741D and fifth surface 741E is D2.

[0091] Opening 741 has a first connecting surface 741F connecting first surface 741A and fourth surface 741D, and a second connecting surface 741G connecting second surface 741B and fifth surface 741E. First connecting surface 741F is located between first surface 741A and fourth surface 741D in the front-rear direction. Second connecting surface 741G is located between second surface 741B and fifth surface 741E in the front-rear direction.

[0092] Distance D1 between first surface 741A and second surface 741B is greater than distance D2 between fourth surface 741D and fifth surface 741E. First connecting surface 741F is formed by an inclined surface inclined at an obtuse angle θ1 with respect to the front-rear direction. Second connecting surface 741G is formed by an inclined surface inclined at an obtuse angle θ2 with respect to the front-rear direction.

[0093] In this way, by forming the first connecting surface 741F and the second connecting surface 741G as inclined surfaces inclined at obtuse angles θ1 and θ2 relative to the front-to-rear direction, respectively, the movement of the main body side coupling 71 between the first opening 741a and the second opening 741b can be made smoother by the first connecting surface 741F and the second connecting surface 741G.

[0094] [Action cam] 6, the device main body 2 has an action cam 75 and a link 76. The action cam 75 is formed of a long plate-like member extending along the front-rear direction, and is supported by the second main body frame 25 so as to be movable in the front-rear direction. The action cam 75 has an abutment portion 751 at its rear end with which the link 76 can abut.

[0095] The action cam 75 is movable between an action position where it acts on the process cartridge 50 and a non-action position where it does not act on the process cartridge 50. The action cam 75 is placed in the action position by moving forward, and is placed in the non-action position by moving rearward. When the action cam 75 is placed in the action position, the action that is exerted on the process cartridge 50 is, for example, a locking action that fixes the process cartridge 50 to the apparatus main body 2, and a separating action that separates the developing roller 52 from the photosensitive drum 51.

[0096] The link 76 has a boss 761 located at the upper end, a pressing portion 762 located at the lower end, and a rotating shaft 763 located midway between the boss 761 and the pressing portion 762. The link 76 is supported by the second main body frame 25 so as to be rotatable about the rotating shaft 763.

[0097] 6, the boss 761 of the link 76 is slidably engaged with the rail 743 of the joint cam 74. The rail 743 guides the boss 761 of the link 76 so that the boss 761 can slide up and down. The boss 761 moves up and down and in the front-to-rear direction as the joint cam 74 moves forward and backward. The pressing portion 762 can come into contact with the contact portion 751 of the action cam 75.

[0098] When the joint cam 74 moves rearward, the link 76 rotates in a direction in which the boss 761 moves rearward, and the pressing portion 762 moves forward. When the joint cam 74 moves forward, the link 76 rotates in a direction in which the boss 761 moves forward, and the pressing portion 762 moves rearward.

[0099] When the pressing portion 762 of the link 76 moves rearward, it comes into contact with the abutment portion 751 of the action cam 75, which is in the action position, and presses it rearward, thereby moving the action cam 75 from the action position to the non-action position. When the pressing portion 762 of the link 76 comes into contact with the abutment portion 751 of the action cam 75, the joint cam 74 and the action cam 75 are connected by the link 76.

[0100] [Joint cam drive mechanism] 4 and 11, the second main body frame 25 has a rotation support part 253 that supports the cylinder 221 of the damper 22 so that the cylinder 221 can rotate about a rotation fulcrum 221a. The rotation support part 253 is located at the rear end and upper end of the second main body frame 25. The cylinder 221 has a protrusion 223 that protrudes on the side opposite the cylinder 221 side of the rotation fulcrum 221a.

[0101] The device main body 2 has a pressing member 81 and a rotating piece 82. The pressing member 81 is supported by the protruding portion 223 of the damper 22, and the rotating piece 82 is supported by the second main body frame 25. In the left-right direction, the rotating piece 82 is located to the left of the joint cam 74, and the pressing member 81 is located to the left of the rotating piece 82.

[0102] The rotating piece 82 is a member for driving the joint cam 74 between a first position and a second position, and is rotatably supported by the second main body frame 25. The rotating piece 82 is rotatable between a first rotation position (position shown in FIG. 11) where the joint cam 74 is driven to the second position, and a second rotation position (position shown in FIG. 12) where the joint cam 74 is driven to the first position.

[0103] The pressing member 81 has a pressing pin 811. The pressing pin 811 protrudes to the right and can come into contact with the rotating piece 82. The pressing member 81 moves in conjunction with the movement of the top cover 21, and comes into contact with the rotating piece 82 when the top cover 21 moves from the closed position to the open position, pressing the rotating piece 82 in the direction of rotation from the first rotation position to the second rotation position.

[0104] The rotating piece 82 has a fitting protrusion 821. The fitting protrusion 821 protrudes to the right and is slidably fitted into the drive hole 744 of the joint cam 74. The fitting protrusion 821 moves the joint cam 74 between the second position and the first position as the rotating piece 82 moves between the first rotation position and the second rotation position.

[0105] As shown in FIG. 11, when the top cover 21 is in the closed position, the pressing pin 811 of the pressing member 81 is in contact with the rotating piece 82, the rotating piece 82 is in the first rotation position, and the joint cam 74 is in the second position.

[0106] When the top cover 21 moves from the closed position to the open position, the damper 22 rotates in a direction in which the cylinder 221 moves upward, and the protrusion 223 of the damper 22 rotates downward. The rotation of the protrusion 223 moves the pressing member 81. In this case, the pressing member 81 moves diagonally downward and forward.

[0107] As the pressing member 81 moves, the pressing pin 811 of the pressing member 81 presses the rotating piece 82 diagonally downward and forward, causing the rotating piece 82 to rotate forward from the first rotation position. When the rotating piece 82 rotates forward, the fitting protrusion 821 that fits into the drive hole 744 moves the joint cam 74 forward from the second position.

[0108] 12, when the top cover 21, which has moved from the closed position, reaches the open position, the rotating piece 82 rotates to the second rotation position, and the joint cam 74 moves to the first position. In this way, the joint cam 74 is moved from the second position to the first position by the rotating piece 82 and the pressing member 81 during the process in which the top cover 21 moves from the closed position to the open position. [Explanation of symbols]

[0109] 1. Image forming device 2. Device body 50 Process cartridge 51 Photosensitive drum 52 Developing roller 71 Body side coupling 74 Joint Cam 521 Cartridge side coupling 711 Joint 711A (of the joint in the third position) outer surface 711B Outer surface (of joint located at 4th position) 712 flange 741 Aperture 741a 1st opening 741b 2nd opening 741A 1st page 741B 2nd side 741C 3rd page 741C-1 First circular arc surface 741C-2 Second arc surface 741C-3 Straight surface 741D 4th page 741E 5th page 741F 1st connecting surface 741G Second connection surface 742 Inclined Rib 742a First inclined rib 742b Second inclined rib d Gap D1 Distance (between the first and second faces) D2 Distance (between the 4th and 5th faces) L1 (first face) length L2 (second surface) length r (joint) radius R (flange) radius X axis (developer roller) Y axis (body side coupling and joint) Z tangent θ1 (first connecting surface) obtuse angle θ2 (second connecting surface) obtuse angle

Claims

1. a cartridge including a cartridge-side coupling for transmitting a driving force to a member inside the cartridge; a main body side coupling that is provided so as to be able to advance and retreat in an axial direction relative to the cartridge side coupling, that is movable between a connection position where it is connected to the cartridge side coupling and a spaced position axially away from the cartridge side coupling, and that has a joint that is engageable with the cartridge side coupling, and a flange that is provided coaxially with the joint; a joint cam that is movable between a first position for disposing the main body side coupling at the separated position and a second position for disposing the main body side coupling at the connected position, and that has an opening including a first opening in which the joint of the main body side coupling located at the separated position is disposed, and a second opening in which the joint of the main body side coupling located at the connected position is disposed and that is provided continuously with the first opening, The second opening is a first surface extending in a moving direction of the joint cam; and a second surface extending in the moving direction and facing the first surface in a direction perpendicular to the moving direction, a distance between the first surface and the second surface in a direction perpendicular to the movement direction is smaller than a sum of a radius r of the joint and a radius R of the flange (r+R) over the entire area of ​​the first surface and the second surface; The joint cam is a plurality of the openings arranged adjacent to each other along the movement direction; The opening is an inclined rib that protrudes from a peripheral edge of the first opening in the axial direction of the body side coupling and abuts against the flange when the joint cam moves, thereby moving the body side coupling between the connected position and the separated position; The inclined rib is a first inclined rib located on one side of a periphery of the first opening in a direction perpendicular to the movement direction and extending in the movement direction; a second inclined rib located on the other side of the periphery of the first opening in a direction perpendicular to the movement direction and extending in the movement direction; An image forming apparatus characterized in that a gap is formed between the end of the first inclined rib at one of the adjacent openings and the end of the second inclined rib at the side adjacent to the second opening of the other opening.

2. a cartridge including a cartridge-side coupling for transmitting a driving force to a member inside the cartridge; a main body side coupling that is provided so as to be able to advance and retreat in an axial direction relative to the cartridge side coupling, that is movable between a connection position where it is connected to the cartridge side coupling and a spaced position axially away from the cartridge side coupling, and that has a joint that is engageable with the cartridge side coupling, and a flange that is provided coaxially with the joint; a joint cam that is movable between a first position for disposing the main body side coupling at the separated position and a second position for disposing the main body side coupling at the connected position, and that has an opening including a first opening in which the joint of the main body side coupling located at the separated position is disposed, and a second opening in which the joint of the main body side coupling located at the connected position is disposed and that is provided continuously with the first opening, The second opening is a first surface extending in a moving direction of the joint cam; and a second surface extending in the moving direction and facing the first surface in a direction perpendicular to the moving direction, a distance between the first surface and the second surface in a direction perpendicular to the movement direction is smaller than a sum of a radius r of the joint and a radius R of the flange (r+R) over the entire area of ​​the first surface and the second surface; The cartridge comprises: A photosensitive drum; a developing cartridge including a developing roller connected to the cartridge-side coupling and movable between a contact position where the developing roller contacts the photosensitive drum and a separation position where the developing roller is separated from the photosensitive drum when the main body-side coupling is located at the connection position, the second opening has a retraction surface that does not interfere with the joint of the main body side coupling when the developing roller moves to the separated position.

3. The joint disposed in the second opening is a third position when the developing roller is located at the contact position; a fourth position when the developing roller is located at the separated position, the fourth position is located closer to the first surface side in a direction perpendicular to the movement direction than the third position and on an opposite side to the first opening side in the movement direction; An end portion of the first surface opposite to the first opening side and an end portion of the second surface opposite to the first opening side are 3. The image forming apparatus according to claim 2, wherein the joint is connected by a third surface having a first arcuate surface along the outer peripheral surface of the joint located at the third position, a second arcuate surface along the outer peripheral surface of the joint located at the fourth position, and a linear surface located between the first arcuate surface and the second arcuate surface and extending in a tangential direction to the first arcuate surface and the second arcuate surface.

4. 4. The image forming apparatus according to claim 1, wherein the first surface and the second surface of the second opening are formed in a straight line extending in the movement direction.

5. the first surface and the second surface of the second opening are disposed opposite to each other in the vertical direction, the second surface is located below the first surface, 5. The image forming apparatus according to claim 1, wherein the second surface is formed shorter than the first surface in the movement direction.

6. The first opening is a fourth surface formed linearly extending in the movement direction; and a fifth surface opposed to the fourth surface in a direction perpendicular to the movement direction and formed linearly extending in the movement direction, The opening is a first connection surface connecting the first surface and the fourth surface, and a second connection surface connecting the second surface and the fifth surface, a distance between the first surface and the second surface in a direction perpendicular to the movement direction is greater than a distance between the fourth surface and the fifth surface in a direction perpendicular to the movement direction, 6. The image forming apparatus according to claim 1, wherein the first connecting surface and the second connecting surface are formed by inclined surfaces inclined at an obtuse angle with respect to the movement direction.

Images