JP7779147B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Conventionally, there is known an image forming apparatus in which a process cartridge is detachably mounted in an apparatus main body equipped with a drive member, the process cartridge is provided with a cartridge-side coupling that transmits drive force to components within the process cartridge, the apparatus main body is provided with a main body-side coupling that is movable between a connected position where it connects to the cartridge-side coupling and a retracted position spaced apart from the cartridge-side coupling, a cam member that is movable between a first position where the main body-side coupling is located in the connected position and a second position where the main body-side coupling is located in the retracted position, and a rotating member that transmits drive force to the drive member (see, for example, Patent Document 1).

The cam member is configured to move to a first position when the cover that opens and closes the device body is closed, placing the body-side coupling in the connected position, and to move to a second position when the cover is opened, placing the body-side coupling in the retracted position.

JP 2012-177840 A

In the image forming device described above, it is necessary to ensure a movable area for the cam member that moves between the first and second positions. However, when the device body is made smaller, the cam member interferes with surrounding components such as rotating components when it moves, making it difficult to ensure a movable area for the cam member.

The present invention provides an image forming device that can prevent the cam member from interfering with surrounding components and ensure a sufficient movable range for the cam member, even when the device body is made smaller.

The image forming device that solves the above problems has the following features:

That is, the image forming apparatus comprises: a cartridge having a cartridge-side coupling that transmits driving force to a component within the cartridge; an apparatus main body to which the cartridge is detachably attached and which is equipped with a motor, the apparatus main body having: a main body-side coupling that is movable between a connected position where it connects to the cartridge-side coupling and a separated position separated from the cartridge-side coupling; a joint cam that is movable between a first position where it positions the main body-side coupling at the connected position and a second position where it positions the main body-side coupling at the separated position; and a rotating member to which driving force is transmitted from the motor, the rotating member having a recess into which an end of the joint cam enters when the joint cam is positioned at the first position.

This prevents the joint cam from interfering with surrounding rotating components, ensuring a sufficient range of motion for the joint cam, even when the device body is made smaller.

The rotating member is a two-stage gear having a first gear and a second gear, and the recess is located between the first gear and the second gear.

This prevents interference between the joint cam and the rotating member without impairing the functionality of the two-stage gear.

The rotating member also has a metal rotating shaft extending along the rotation axis.

The portions of the rotating member where the recesses are formed tend to be thinner and less rigid, but by making the rotating shaft out of metal, the rigidity of the portions of the rotating member where the recesses are formed can be ensured.

The device body also includes a cover that covers the rotating member, and the cover has a restricting rib that engages with the rotating member and restricts movement of the rotating member toward the rotation axis.

This allows for space savings in the direction of the rotation axis compared to, for example, a configuration that restricts movement of the rotating member in the direction of the rotation axis, where a hook that engages with the rotating shaft extends from the rotating member in the direction of the rotation axis. Furthermore, by forming a restricting rib on the cover of the rotating member that engages with the rotating member, additional machining is not required to engage the hook with the rotating shaft, which helps prevent costs from increasing.

The rotating member is also a fixing gear that transmits driving force to a fixing device that fixes the toner image onto the sheet.

This prevents interference between the rotating member and the joint cam.

The rotating member also has a first portion made of a first material and a second portion made of a second material different from the first material, the first material being a heat-resistant resin, and the first portion being located closer to the fixing unit than the second portion.

By forming the first part, which is located near the fixing unit, from heat-resistant resin, the effect of heat from the fixing unit on the rotating member can be reduced.

The device main body also has an action cam that can move between an action position where it acts on the cartridge and a non-action position where it does not act on the cartridge, and a link that connects the action cam and the joint cam, and the joint cam slidably guides a boss on the link.

This prevents interference between the joint cam rail and the rotating member.

In addition, the upper end of the rail is located below the rotation axis of the rotating member.

This ensures a large gap between the joint cam and the rotating member when the rail enters the recess in the rotating member.

Furthermore, the boss of the link moves between a lower position when the joint cam is in the first position and an upper position higher than the lower position when the joint cam is in a third position between the first and second positions, and the boss in the lower position does not interfere with the rotating member.

This prevents interference between the link boss and the rotating member when the joint cam moves to the first position.

The device also includes an open/close cover that is movable between a closed position that closes the device body and an open position that opens the device body, and a pivotable piece that drives the joint cam and is capable of rotating between a first pivot position that drives the joint cam to a first position and a second pivot position that drives the joint cam to a second position, the pivot piece having a relief shape that prevents interference with the link during the process of rotating from the first pivot position to the second pivot position.

As a result, the relief shape prevents interference between the pivot piece and the link as the pivot piece pivots from the first pivot position to the second pivot position, allowing the joint cam to be driven smoothly from the first position to the second position.

The device also includes a pressing member that moves in conjunction with the movement of the opening/closing cover, contacts the rotating piece when the opening/closing cover moves from the closed position to the open position, and presses the rotating piece in the direction of rotation from the first rotating position to the second rotating position, and a profile member having a profile that defines the movement trajectory of the pressing member, wherein the rotating piece has a first contact position where the pressing member comes into contact when the opening/closing cover is in the closed position, a second contact position where the pressing member comes into contact when the opening/closing cover is in a position intermediate between the closed position and the open position, and a third contact position where the pressing member comes into contact when the opening/closing cover is in the open position, and the pressing member is in contact with the first contact position, the pressing member is rotated to the first pivot position, and is rotated to the second pivot position when the pressing member is in contact with the second contact position and the third contact position, the pressing member moves along the profile while contacting a first region of the rotating piece from the first contact position to the second contact position as the opening/closing cover moves from the closed position to the intermediate position, and the pressing member moves along the profile while contacting a second region of the rotating piece from the second contact position to the third contact position as the opening/closing cover moves from the intermediate position to the open position, and the relief shape is formed in the second region of the rotating piece.

In this way, the relief shape of the rotating piece is formed in the second region, but since a large load from the pressing member does not act on the second region, there is no need to make the rotating piece and pressing member large, which allows for the device body to be made more compact.

According to the present invention, even when the device body is made smaller, interference between the joint cam and surrounding components can be suppressed, ensuring the joint cam's range of motion.

FIG. 2 is a central cross-sectional view showing the image forming apparatus. FIG. 2 is a perspective view showing the image forming apparatus when the top cover is in a closed position. FIG. 2 is a perspective view showing the image forming apparatus when the top cover is in the open position. FIG. FIG. 2 is a side view showing the left side of the device main body. FIG. 10 is a front cross-sectional view showing a fixing gear supported by the second main body frame. 1A is a perspective view showing a fixing gear, and FIG. 1B is a front view showing the fixing gear. 1A is an exploded perspective view showing a fixing gear, FIG. 1B is a view showing a first part of the fixing gear, and FIG. 1C is a view showing a second part of the fixing gear. 1A is a plan sectional view showing the main body side coupling in a separated position, and FIG. 1B is a plan sectional view showing the main body side coupling in a connected position. 1A is a perspective view showing a joint cam, and FIG. 1B is a side view showing the joint cam. 1A is a left side view showing the link, FIG. 1B is a right side view showing the link, and FIG. 1C is a front view showing the link. 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. 10 is a side view showing the rear part of the left side of the device main body when the joint cam is in a third position between the first position and the second position. FIG. 10 is a side cross-sectional view showing the rear part on the left side of the apparatus main body when the top cover is in an intermediate position. FIG. A side view showing the rear part of the left side of the device body when the top cover is in the open position. 1A is a left side view showing the pressing member, FIG. 1B is a right side view showing the pressing member, and FIG. 1C is a front view showing the pressing member. FIG. 1A is a perspective view showing a rotating piece, and FIG. 1B is a rear view showing the rotating piece. FIG.

Next, a description of an embodiment of the present invention will be given with reference to the accompanying drawings.

[Image forming equipment]
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.

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

The image forming device 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 sheets S transported by the paper feed unit 3, and a fuser 6 that fuses the toner image to the sheets S.

The device main body 2 is formed in a roughly rectangular parallelepiped shape and houses the paper feed unit 3, image forming unit 5, and fuser unit 6. An opening 2A is formed on the top surface of the device main body 2. The image forming device 1 has a top cover 21 that can open and close the opening 2A of the device main body 2. The top cover 21 is an example of an openable cover.

The top cover 21 is supported on the device body 2 so that it can rotate around a rotation shaft 21a at the rear end. By rotating around the rotation shaft 21a, the top cover 21 can move between a closed position (position shown in Figure 2) in which it closes the opening 2A, and an open position (position shown in Figure 3) in which it opens the opening 2A. The top cover 21 is formed with a paper output tray 21b that slopes downward from the front to the rear.

As shown in FIG. 3, a damper 22 is interposed between the top cover 21 and the device main body 2. The dampers 22 are provided at the left and right ends of the image forming device 1. The damper 22 has a cylinder 221 and a piston 222. The cylinder 221 is supported on the device main body 2 so that it can rotate around a rotation fulcrum 221a. The piston 222 is configured to be extendable and retractable relative to the cylinder 221, and is supported on the top cover 21 so that it can rotate around a rotation fulcrum 222a.

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

The paper feed unit 3 is located at the bottom of the device main body 2 and transports sheets S supported in the paper feed tray 10 to the image forming unit 5 using 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 main body 2 and a separation position where it is pulled forward from the storage position.

The sheet transport unit 30 includes a paper feed roller 32, a separation roller 33, a separation pad 33a, a pair of transport rollers 34, and a pair of registration rollers 35. Within the device main body 2, a transport path P for the sheet S is configured, running from the paper feed tray 10 to the image forming unit 5 and then to the paper discharge tray 21b.

The sheets S supported in 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 transport path P. The paper feed roller 32 is a roller that transports 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 separation means that separates the sheets S supported in the paper feed tray 10 one by one.

The sheet S sent to the transport path P is transported toward the image forming unit 5 by a transport roller pair 34 and a registration roller pair 35. The registration roller pair 35 regulates the movement of the leading edge of the transported sheet S, temporarily stopping it, and then transports the sheet S toward the image forming unit 5 at a predetermined timing.

The image forming unit 5 is located above the paper feed 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 corresponds to one of the colors: black, yellow, magenta, and cyan. The process cartridges 50 are detachably mounted in the device 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 consists of a drum cartridge including the photosensitive drum 51 and a developing cartridge including the developing roller 52.

The process cartridge 50 is mounted in the device main body 2 with the rotational axis 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.

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 positioned close to and above the photosensitive drum 51 when the top cover 21 is closed. The exposure section 59a is composed of an LED array with multiple LED elements arranged side by side in the left-to-right direction.

A transfer belt 41 is disposed below and 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 form the belt device 40. A transfer roller 44 is disposed at a position facing each photosensitive drum 51 across the transfer belt 41.

In the image forming unit 5, the photosensitive drums 51, which are 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, forming electrostatic latent images on the surfaces of the photosensitive drums 51.

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. This forms a toner image on the surface of the photosensitive drum 51.

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 it faces the sheet S, the toner image on the surface of the photosensitive drum 51 is transferred onto the sheet S by the transfer bias applied to the transfer roller 44.

In this embodiment, the transfer belt 41 is configured as a conveyor 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 then transferred to the sheet S.

The sheet S with the transferred toner image is transported to the fuser 6. The fuser 6 includes a heating roller 61 and a pressure roller 62 that presses against the heating roller 61. The heating roller 61 is heated by a power source (not shown) provided in the device main body 2. The device main body 2 includes a motor 4, which serves as a driving member, and a fuser gear 63 (see Figure 1), and the driving force from the motor 4 is transmitted to the heating roller 61 via the fuser gear 63. The fuser gear 63 is an example of a rotating member to which the driving force is transmitted from the driving member. The toner image on the sheet S transported to the fuser 6 is thermally fixed as it passes between the heating roller 61 and the pressure roller 62.

The sheet S with the thermally fixed toner image is transported downstream in the transport direction from the fixing unit 6, then further transported by the intermediate discharge roller pair 64 and the discharge roller pair 65 located downstream in the transport direction of the intermediate discharge roller pair 64, and discharged onto the discharge tray 21b.

As shown in Figure 4, the device main body 2 comprises a first body frame 24 and a second body frame 25, which 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 main body 2 and extends in the front-to-back and up-to-down directions. The second body frame 25 is located at the left end of the device main body 2 and extends in the front-to-back and up-to-down directions.

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 removably supported by the first body frame 24 and the second body frame 25.

[Fuser gear]
4 and 5, the fixing gear 63 is supported on the rear end of the second main body frame 25. The fixing gear 63 is a gear for transmitting a driving force to the fixing device 6 that fixes the toner image on the sheet S.

As shown in Figures 6 to 8, the fixing gear 63 is rotatable around a rotation axis X, and is positioned with the rotation axis X aligned in the left-right direction. The fixing gear 63 has a first portion 63A, a second portion 63B, and a rotation shaft 63C.

The first part 63A is formed from a resin member and has a first gear 631, a mating part 632, a recess 633, and a flange part 634. The first gear 631 is connected to the heating roller 61 of the fixing unit 6 and is configured to be able to transmit driving force to the heating roller 61. The mating part 632 is configured to be able to mate with the second part 63B.

The recess 633 is formed with a smaller diameter than the first gear 631 and the mating portion 632, and is formed with a shape that is recessed toward the inner diameter side relative to the outer diameter shapes of the first gear 631 and the mating portion 632. The flange portion 634 is formed with a brim shape that protrudes toward the outer diameter side relative to the mating portion 632. On the first gear 631, the first gear 631, recess 633, flange portion 634, and mating portion 632 are arranged in this order from right to left.

The second part 63B is formed from a resin member and has a second gear 635 and a mating part 636. In the second part 63B, the mating part 636 and the second gear 635 are arranged in this order from right to left. The second gear 635 is connected to the motor 4, and receives driving force from the motor 4. The mating part 636 can be mated with the mating part 632 of the first part 63A, and the mating part 632 and the mating part 636 are mated together, connecting the first part 63A and the second part 63B so that they can rotate together.

The fixing gear 63, formed by connecting the first portion 63A and the second portion 63B, is a two-stage gear having a first gear 631 and a second gear 635. In the fixing gear 63, the first gear 631, the recessed portion 633, and the second gear 635 are arranged in this order from right to left. In other words, the recessed portion 633 is located between the first gear 631 and the second gear 635 in the left-right direction.

The rotating shaft 63C is formed by a metal shaft member extending along the rotation axis X, and is fitted over the first portion 63A and second portion 63B. The first portion 63A and second portion 63B are configured to be rotatable about the rotating shaft 63C. In the fixing gear 63, the first portion 63A has a recess 633 with a smaller diameter than the rest of the fixing gear 63, and the portion where the recess 633 is formed tends to be thinner than the rest of the fixing gear 63, resulting in reduced rigidity. However, by making the rotating shaft 63C out of metal, it is possible to ensure the rigidity of the portion of the fixing gear 63 where the recess 633 is formed.

The device main body 2 is disposed to the left of the second main body frame 25 and includes a sheet metal frame 26 supported by the second main body frame 25. The rotation shaft 63C is supported by the sheet metal frame 26, and with the rotation shaft 63C supported by the sheet metal frame 26, the fixing gear 63 is supported by the second main body frame 25 via the sheet metal frame 26.

The second main body frame 25 has a through-hole 251 that penetrates in the left-right direction. The fixing gear 63 is inserted through the through-hole 251 and is arranged from right to left on the second main body frame 25.

The first portion 63A of the fixing gear 63 is located to the right of the second portion 63B, and the first gear 631 of the first portion 63A protrudes rightward from the second body frame 25. Furthermore, the second gear 635 of the second portion 63B is located leftward from the second body frame 25. In other words, in the left-right direction, the first portion 63A protrudes inward from the second body frame 25 of the device body 2 on which the fixing unit 6 is disposed, and the second portion 63B is located outward from the second body frame 25 of the device body 2, with the first portion 63A being located closer to the fixing unit 6 than the second portion 63B.

In the fixing gear 63, the first portion 63A is made of a first material, and the second portion 63B is made of a second material different from the first material. The first material is made of a heat-resistant resin, and the second portion 63B is made of a non-heat-resistant resin.

The first portion 63A, which is made of the first material, is located closer to the fuser 6, which is a heat source, than the second portion 63B, which is made of the second material. However, by forming the first portion 63A, which is located closer to the fuser 6, from a heat-resistant resin, it is possible to reduce the effect of heat from the fuser 6 on the fuser gear 63. Furthermore, by forming the second portion 63B, which is located farther from the fuser 6 than the first portion 63A, from a non-heat-resistant resin that is cheaper than heat-resistant resin, it is possible to reduce the cost of the fuser gear 63. However, it is also possible to form the second portion 63B from the same heat-resistant resin as the first portion 63A.

The device main body 2 is equipped with a cover 27 that covers the fixing gear 63. The cover 27 is positioned between the second main body frame 25 and the sheet metal frame 26 in the left-right direction and is supported by the sheet metal frame 26. The cover 27 covers the second part 63B of the fixing gear 63 and the left end of the first part 63A.

The cover 27 has a restricting rib 271 that protrudes from the outer diameter side to the inner diameter side of the fixing gear 63. The restricting rib 271 is located to the right of the flange portion 634 on the first part 63A of the fixing gear 63 and can be engaged with the flange portion 634. By engaging with the flange portion 634, the restricting rib 271 can restrict movement of the fixing gear 63 in the direction of the rotation axis X.

By providing the restricting rib 271 on the cover 27, it is possible to reduce the space required in the direction of the rotation axis X, for example, compared to when a hook that engages with the rotation axis 63C is formed by extending from the first portion 63A of the fixing gear 63 in the direction of the rotation axis X as a configuration for restricting movement of the fixing gear 63 in the direction of the rotation axis X. Furthermore, by forming the restricting rib 271 that engages with the fixing gear 63 on the cover 27 of the fixing gear 63, additional processing is not required to engage the hook with the rotation axis 63C, which helps prevent costs from increasing.

[Cartridge side coupling]
9, 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 cartridge-side coupling 521 is located to the right of the second main body frame 25.

[Main body side coupling]
9, 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 that is connected 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.

The main body side coupling 71 is located to the left of the second main body frame 25 and is supported by the second main body frame 25 so that it can move left and right. The main body side coupling 71 can move between a right connected position (position shown in Figure 9(b)) where it connects to the cartridge side coupling 521, and a separated position (position shown in Figure 9(a)) to the left of the connected position where it is separated from the cartridge side coupling 521. The main body side coupling 71 is located in the connected position when the top cover 21 is in the closed position, and in the separated position when the top cover 21 is in the open position.

The main body side coupling 71 has a joint portion 711 that connects to the cartridge side coupling 521 and a flange portion 712 that has a larger diameter than the joint portion 711.

The second main body frame 25 has a communication hole 252 that penetrates 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 portion 711 protrudes from the left of the second main body frame 25 through the communication hole 252 to the right of the second main body frame 25 (see Figure 9(b)). When the main body side coupling 71 is in the separated position, the main body side coupling 71 is entirely retracted to the left of the second main body frame 25 (see Figure 9(a)).

The drive gear 72 is connected to the motor 4 and is configured to rotate 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 driving force from the motor 4, and the driving force is transmitted to the developing roller 52 through the joint portion 711 and 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 portion 711 and cartridge side coupling 521 are separated, so even if the drive gear 72 is driven by the driving force from the motor 4, the driving force is not transmitted to the developing roller 52.

The spring 70 is interposed between the flange portion 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 allows the main body side coupling 71 to move from the separated position to the connected position.

[Main body side coupling drive mechanism]
5 and 9, the apparatus main body 2 has a joint cam 74 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 extending along the front-rear direction, and is located in front of the fixing gear 63. By moving rearward, the joint cam 74 can be located at a first position (position shown in FIG. 9(b)) where the main body side coupling 71 is located at the connected position, and by moving forward, the joint cam 74 can be located at a second position (position shown in FIG. 9(a)) where the main body side coupling 71 is located at the separated position.

As shown in Figures 9 and 10, the joint cam 74 has an opening 741, an inclined cam 742, a rail 743, and a drive hole 744. The openings 741 and inclined cams 742 are provided corresponding to the four main body couplings 71, and are arranged side by side in four locations along the front-to-rear direction.

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

The inclined cam 742 is formed on the upper and lower edges of the second opening 741b in the opening 741. The inclined cam 742 has an inclined surface that protrudes to the left as it moves from the front to the rear. The flange portion 712 of the main body side coupling 71 can abut against the inclined cam 742.

When the joint cam 74 has moved rearward and is in the first position, the joint portion 711 of the main body side coupling 71 is located in the first opening 741a of the opening 741. When the joint portion 711 is located in the first opening 741a, the flange portion 712 is not in contact with the inclined cam 742, and the main body side coupling 71 is biased to the right by the biasing force of the spring 73 and is positioned in the connected position.

When the joint cam 74, which is in the first position, moves forward, the flange portion 712 abuts against the inclined cam 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 portion 711 is positioned at the second opening 741b of the opening 741, the main body coupling 71, which has moved leftward, is positioned at the separated position. In this way, as the joint cam 74 moves forward and backward between the first and second positions, the main body coupling 71 is driven between the connected and separated positions.

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.

[Positional relationship between joint cam and fixing gear]
5, 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 on 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.

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

As shown in FIG. 11, the link 76 extends generally in the vertical direction and has a boss 761 located at the upper end, a pressing portion 762 located at the lower end, and a pivot 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 around the pivot shaft 763.

As shown in Figure 5, 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 it can slide up and down. The boss 761 moves up and down as the joint cam 74 moves forward and backward. The pressing portion 762 can abut against the abutment portion 751 of the action cam 75.

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

When the pressing portion 762 of the link 76 moves rearward, it abuts against the abutment portion 751 of the action cam 75, which is in the active position, and presses it rearward, moving the action cam 75 from the active position to the inactive position. When the pressing portion 762 of the link 76 abuts against the abutment portion 751 of the action cam 75, the joint cam 74 and action cam 75 are connected by the link 76.

As shown in Figures 5, 9(b), and 12, when the top cover 21 is in the closed position and the joint cam 74 has moved rearward to the first position, the rear end of the joint cam 74 and the fixing gear 63 overlap in the front-to-rear direction. In other words, in the image forming device 1, the joint cam 74 and the fixing gear 63 in the first position are positioned so that they overlap in the front-to-rear direction, thereby reducing the size of the device main body 2.

On the other hand, when the joint cam 74 is located in the first position, the rear end of the joint cam 74 is inserted into the recess 633 of the fixing gear 63. Specifically, when the joint cam 74 is located in the first position, the upper end of the rail 743 located at the rear end of the joint cam 74 is located within the recess 633 of the fixing gear 63 and is not in contact with the fixing gear 63.

In this way, by configuring the rear end of the joint cam 74 in the first position to enter the recess 633 of the fixing gear 63, interference between the joint cam 74 and the fixing gear 63 can be prevented even if the joint cam 74 in the first position and the fixing gear 63 are positioned so that they overlap in the front-to-rear direction. As a result, even when the device main body 2 is made more compact, the rail 743 of the joint cam 74 does not interfere with the fixing gear 63, and it is possible to ensure a movable range for the joint cam 74 in the front-to-rear direction.

In addition, the recess 633 of the fixing gear 63, into which the end of the joint cam 74 enters, is located between the first gear 631 and second gear 635 of the fixing gear 63, which is configured as a two-stage gear, so interference between the fixing gears 63 can be prevented without impairing the function of the fixing gear 63.

Furthermore, as shown in FIG. 12, the upper end of the rail 743 on the joint cam 74 is located below the rotation axis X of the fixing gear 63. This makes it possible to ensure a large gap between the joint cam 74 and the fixing gear 63 when the upper end of the rail 743 enters the recess 633 of the fixing gear 63.

Also, as shown in Figure 12, when the joint cam 74 is in the first position, the link 76 is in a tilted position with the boss 761 located rearward of the pivot shaft 763, and the boss 761 of the link 76 is moved to the lower position. The lower position of the boss 761 is a position where the boss 761 is at the lower end of the rail 743. When the top cover 21 rotates from the closed position to the open position and the joint cam 74 moves forward from the first position, the boss 761 is guided by the rail 743 while moving forward, and moves upward from the lower position.

As shown in FIG. 13, when the joint cam 74 moves forward from the first position and reaches the third position between the first and second positions, the link 76 assumes an upright position with the boss 761 positioned substantially above the pivot shaft 763, and the boss 761 of the link 76 is positioned at an upper position higher than the lower position. The upper position of the boss 761 is the position where the boss 761 is at the upper end of the rail 743. As shown in FIG. 14, when the top cover 21 rotates further toward the open position and the joint cam 74 moves from the third position to the second position, the link 76 assumes a tilted position with the boss 761 positioned forward of the pivot shaft 763, and the boss 761 of the link 76 is positioned at the lower position.

In this way, the boss 761 of the link 76 moves between the lower and upper positions while the joint cam 74 moves between the first and second positions, and when the joint cam 74 is in the first and second positions, the boss 761 moves to the lower position. Furthermore, the lower position of the boss 761 is set to a position where the boss 761 and the fixing gear 63 do not interfere with each other. For example, the boss 761 in the lower position can be configured to be positioned below the fixing gear 63. Therefore, even when the joint cam 74 moves to the first position where it approaches the fixing gear 63, interference between the boss 761 and the fixing gear 63 can be prevented.

When the top cover 21 rotates from the closed position to the open position, the joint cam 74 moves forward from the first position and reaches the second position, and the position of the top cover 21 is an intermediate position between the closed position and the open position (the position shown in Figure 14). As shown in Figure 15, even when the top cover 21 rotates further from the intermediate position and moves to the open position, the joint cam 74 remains in the second position.

[Joint cam drive mechanism]
4 and 12, the second main body frame 25 has a rotation support portion 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 portion 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.

The device main body 2 has a pressing member 81, a pivoting piece 82, and a profile member 83. The pressing member 81 is supported by the protrusion 223 of the damper 22, and the pivoting piece 82 and profile member 83 are supported by the second main body frame 25. In the left-right direction, the pivoting piece 82 is located to the left of the joint cam 74, the pressing member 81 is located to the left of the pivoting piece 82, and the profile member 83 is located to the left of the pressing member 81.

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 on the second main body frame 25. The rotating piece 82 is rotatable between a first rotation position (position shown in Figure 12) that drives the joint cam 74 to the first position, and a second rotation position (position shown in Figures 14 and 15) that drives the joint cam 74 to the second position.

As shown in Figure 16, the pressing member 81 has a main body 811, a support pin 812, a pressing pin 813, and a profile pin 814. The main body 811 is formed from a rectangular plate-like member that is long in the vertical direction. The plate surface of the main body 811 faces in the left-right direction.

The support pin 812 protrudes leftward from the left side surface at the upper end of the main body 811 and is rotatably supported by the protrusion 223 of the damper 22. The pressure pin 813 protrudes rightward from the right side surface at the lower end of the main body 811 and is capable of contacting the pivot piece 82. The profile pin 814 protrudes leftward from the left side surface at the lower end of the main body 811 and is configured to be able to engage with the profile member 83. The profile pin 814 and pressure pin 813 are arranged coaxially.

The pressing member 81 moves in conjunction with the movement of the top cover 21, and when the top cover 21 moves from the closed position to the open position, it comes into contact with the rotating piece 82 and presses the rotating piece 82 in the direction of rotation from the first rotation position to the second rotation position.

As shown in Figures 17 and 18, the rotating piece 82 has a main body portion 821, a supported portion 822, and a fitting protrusion 823. The main body portion 821 is formed from a generally trapezoidal plate-like member whose front-to-back width at the lower end is smaller than that at the upper end. The plate surface of the main body portion 821 faces in the left-to-right direction. The supported portion 822 is formed at the front and upper end of the main body portion 821. The supported portion 822 is rotatably supported by the second main body frame 25, and the rotating piece 82 can move between a first rotation position and a second rotation position by rotating around the supported portion 822.

The fitting protrusion 823 protrudes rightward from the right side surface of the main body 821 and slidably fits into the drive hole 744 of the joint cam 74. The fitting protrusion 823 moves up and down along the drive hole 744 as the rotating piece 82 moves between the first and second rotation positions. When the rotating piece 82 is in the first rotation position, the fitting protrusion 823 is located at the vertical midpoint of the drive hole 744 (position shown in Figure 12), and when the rotating piece 82 is in the second rotation position, it is located at the upper end above the vertical midpoint of the drive hole 744 (position shown in Figures 14 and 15).

The main body 821 has an upper end surface 821A and a rear end surface 821B, with which the pressing pin 813 of the pressing member 81 can come into contact. The main body 821 has a first contact position P1, a second contact position P2, and a third contact position P3 at which the pressing pin 813 comes into contact on the upper end surface 821A and the rear end surface 821B.

The first contact position P1 is located at the rear end of the upper end surface 821A of the main body 821, and is the position where the pressing pin 813 comes into contact when the top cover 21 is in the closed position. The second contact position P2 is located at the upper end of the rear end surface 821B of the main body 821, and is the position where the pressing pin 813 comes into contact when the top cover 21 is in the intermediate position. The third contact position P3 is located at the lower end of the rear end surface 821B of the main body 821, and is the position where the pressing pin 813 comes into contact when the top cover 21 is in the open position.

In the main body 821, the region from the first contact position P1 to the second contact position P2 on the upper end surface 821A and the rear end surface 821B is the first region R1, and the region from the second contact position P2 to the third contact position P3 on the upper end surface 821A and the rear end surface 821B is the second region R2.

The main body 821 has a recess Fa that prevents interference with the upper end of the link 76, which rotates around the rotation axis 763, during movement between the first and second rotation positions. The recess Fa is formed in the second region R2 on the rear end surface 821B of the main body 821.

The recessed portion Fa is recessed forward from the straight line L connecting the upper end Fa1 and lower end Fa2 of the recessed portion Fa. This increases the distance between the rear end surface 821B of the main body 821 and the upper end of the link 76 located behind the main body 821, preventing interference between the pivot piece 82 and the link 76.

As shown in Figure 19, the profile member 83 is formed from a plate-shaped member with its plate surface facing left and right, and has a profile groove 831 into which the profile pin 814 of the pressing member 81 engages. The profile groove 831 is formed on the right side surface of the profile member 83, and the profile pin 814 engages from the right.

The pressing member 81 moves in conjunction with the rotational movement of the damper 22, and the profile groove 831 defines the movement trajectory of the pressing pin 813 when the pressing member 81 moves. In other words, when the pressing member 81 moves, the profile pin 814 moves along the profile groove 831, thereby defining the movement trajectory of the pressing pin 813. The profile groove 831 is an example of a profile that defines the movement trajectory of the pressing member.

The profile groove 831 has a first groove portion 831A, a second groove portion 831B, and a bent portion 831C. The first groove portion 831A is inclined obliquely downward toward the front from the upper end of the profile member 83. The second groove portion 831B is formed continuously with the lower end of the first groove portion 831A and is inclined obliquely downward toward the front at a smaller angle relative to the horizontal than the first groove portion 831A. The bent portion 831C is located at the boundary between the first groove portion 831A and the second groove portion 831B, and the profile groove 831 is bent at the bent portion 831C.

As shown in Figure 12, when the top cover 21 is in the closed position, the first contact position P1 of the rotating piece 82 contacts the pressing pin 813 of the pressing member 81, the rotating piece 82 is in the first rotation position, and the joint cam 74 is in the first position.

When the top cover 21 moves from the closed position to the open position, the damper 22 rotates in the direction in which the cylinder 221 moves upward, and the protrusion 223 of the damper 22 rotates downward. The rotation of the protrusion 223 causes the pressing member 81 to move. In this case, the pressing member 81 moves diagonally downward and forward along the first groove portion 831A of the profile groove 831 in which the profile pin 814 engages.

As the pressing member 81 moves along the profile groove 831, the upper end surface 821A or rear end surface 821B of the rotating piece 82 is pressed diagonally downward and forward by the pressing pin 813 of the pressing member 81, causing the rotating piece 82 to rotate forward from the first rotation position around the supported portion 822. When the rotating piece 82 rotates forward, the fitting protrusion 823, which fits into the drive hole 744, moves the joint cam 74 forward from the first position.

As shown in Figure 14, when the top cover 21 reaches an intermediate position while moving toward the open position, the profile pin 814 of the pressing member 81 is positioned at the bent portion 831C of the profile groove 831, and the rotating piece 82 pressed by the pressing member 81 has rotated to the second rotation position. In this case, the joint cam 74 moved forward by the rotating piece 82 is positioned at the second position, and the pressing pin 813 of the pressing member 81 is in contact with the second contact position P2 of the rotating piece 82.

In this way, as the top cover 21 moves from the closed position to the intermediate position, the pressing member 81 moves along the profile groove 831 while contacting the first region R1 of the rotating piece 82, from the first contact position P1 to the second contact position P2. Furthermore, when the pressing member 81 contacts the second contact position P2 of the rotating piece 82, the rotating piece 82 rotates to the second rotation position.

When the rotating piece 82 rotates from the first rotation position to the second rotation position, the rear end surface 821B of the rotating piece 82 has a recess shape Fa, which prevents interference between the rotating piece 82 and the link 76 and allows the joint cam 74 to be driven smoothly from the first position to the second position.

When the top cover 21 moves from the intermediate position toward the open position, the profile pin 814 of the pressing member 81 moves from the bent portion 831C of the profile groove 831 along the second groove portion 831B.

As shown in Figure 15, when the top cover 21, having moved from an intermediate position, reaches the open position, the profile pin 814 of the pressing member 81 is positioned at the front end of the second groove portion 831B, and the rotating piece 82 has rotated to the second rotation position. In this case, the joint cam 74 is positioned at the second position, and the pressing pin 813 of the pressing member 81 is in contact with the third contact position P3 of the rotating piece 82.

The second groove portion 831B is formed with an inclination angle and shape that matches the rear end surface 821B of the pivot piece 82 in the second pivot position. When the profile pin 814 moves from the bent portion 831C of the profile groove 831 to the front end of the second groove portion 831B, the pivot piece 82 remains in the second pivot position, and the joint cam 74 remains in the second position. Therefore, when the profile pin 814 moves from the bent portion 831C of the profile groove 831 to the front end of the second groove portion 831B, no large load is applied from the pressing member 81 to the rear end surface 821B of the pivot piece 82.

In this way, as the top cover 21 moves from the intermediate position to the open position, the pressing member 81 moves along the profile groove 831 while contacting the second region R2 of the rotating piece 82, from the second contact position P2 to the third contact position P3. Furthermore, the rotating piece 82 rotates to the second rotation position when the pressing member 81 contacts the third contact position P3 of the rotating piece 82.

The relief shape Fa of the pivot piece 82 is formed in the second region R2 from the second contact position P2 to the third contact position P3 on the rear end face 821B, where no large load is applied from the pressing member 81. Therefore, there is no need to make the pivot piece 82 and pressing member 81 large, making it possible to reduce the size of the device main body 2.

REFERENCE SIGNS LIST 1 Image forming apparatus 2 Apparatus main body 2A Opening 4 Motor 6 Fixing unit 21 Top cover 27 Cover 50 Process cartridge 52 Developing roller 63 Fixing gear 63A First part 63B Second part 63C Rotation shaft 71 Main body side coupling 74 Joint cam 75 Action cam 76 Link 81 Pressing member 82 Rotating piece 83 Profile member 271 Regulating rib 521 Cartridge side coupling 631 First gear 633 Recess 635 Second gear 743 Rail 761 Boss 831 Profile groove Fa Relief shape P1 First contact position P2 Second contact position P3 Third contact position R1 First region R2 Second region S Sheet X Rotation axis

Claims (11)

a cartridge having a cartridge-side coupling for transmitting a driving force to a member inside the cartridge;
An apparatus main body to which the cartridge is detachably attached and which includes a motor,
a main body side coupling that is movable between a connection position where it is connected to the cartridge side coupling and a separation position where it is separated from the cartridge side coupling;
a joint cam movable between a first position at which the main body side coupling is disposed at the connected position and a second position at which the main body side coupling is disposed at the separated position;
a device body having a rotating member to which a driving force is transmitted from the motor;
Equipped with
The image forming apparatus according to claim 1, wherein the rotating member has a recess into which an end of the joint cam enters when the joint cam is located at the first position. the rotating member is a two-stage gear having a first gear and a second gear,
The image forming apparatus according to claim 1 , wherein the recess is located between the first gear and the second gear. An image forming apparatus according to claim 1 or claim 2, wherein the rotating member has a metal rotating shaft extending along the rotation axis. the device body includes a cover that covers the rotary member,
4. The image forming apparatus according to claim 1, wherein the cover has a restricting rib that engages with the rotating member to restrict movement of the rotating member in the direction of the rotation axis. The image forming apparatus described in any one of claims 1 to 4, wherein the rotating member is a fixing gear that transmits driving force to a fixing device that fixes a toner image on a sheet. The rotating member has a first portion formed from a first material and a second portion formed from a second material different from the first material,
the first material is a heat-resistant resin,
The image forming apparatus according to claim 5 , wherein the first section is located closer to the fixing unit than the second section. the device main body has an action cam that is movable between an action position where it acts on the cartridge and a non-action position where it does not act on the cartridge, and a link that connects the action cam and the joint cam;
the joint cam has a rail that slidably guides a boss of the link,
7. The image forming apparatus according to claim 1, wherein the end of the rail is positioned within the recess of the rotating member when the joint cam is positioned at the first position. An image forming apparatus as described in claim 7, wherein the upper end of the rail is located below the rotation axis of the rotating member. the boss of the link moves between a lower position when the joint cam is in the first position and an upper position higher than the lower position when the joint cam is in a third position between the first position and the second position,
9. The image forming apparatus according to claim 7, wherein the boss at the lower position does not interfere with the rotating member. an opening/closing cover that is movable between a closed position that closes the device body and an open position that opens the device body;
a rotating piece that is rotatably provided and drives the joint cam, the rotating piece being rotatable between a first rotation position that drives the joint cam to a first position and a second rotation position that drives the joint cam to a second position;
Equipped with
An image forming apparatus as described in any one of claims 7 to 9, wherein the pivot piece has a relief shape that prevents interference with the link during the process of pivoting from the first pivot position to the second pivot position. a pressing member that moves in accordance with the movement of the opening/closing cover, that comes into contact with the rotating piece when the opening/closing cover moves from the closed position to the open position, and that presses the rotating piece in a direction in which the rotating piece rotates from the first rotating position toward the second rotating position;
a profile member having a profile formed thereon that defines a movement trajectory of the pressing member;
Equipped with
the rotating piece has a first contact position with which the pressing member comes into contact when the open-close cover is in the closed position, a second contact position with which the pressing member comes into contact when the open-close cover is in an intermediate position between the closed position and the open position, and a third contact position with which the pressing member comes into contact when the open-close cover is in the open position, the rotating piece rotates to the first rotating position when the pressing member is in contact with the first contact position, and rotates to the second rotating position when the pressing member is in contact with the second contact position and the third contact position,
the pressing member moves along the profile while contacting a first region of the rotating piece from the first contact position to the second contact position during the process of the opening/closing cover moving from the closed position to the intermediate position, and the pressing member moves along the profile while contacting a second region of the rotating piece from the second contact position to the third contact position during the process of the opening/closing cover moving from the intermediate position to the open position,
The image forming apparatus according to claim 10 , wherein the recessed portion is formed in the second region of the rotating piece.