Image-forming apparatus

Abstract

To provide an image-forming apparatus that, even when a drawer is configured to be drawable from a body, can maintain a sheet inclination correction function of a resist roller.SOLUTION: An image-forming apparatus 1 comprises: an apparatus body 2 that includes a front surface 2A including a front opening 2F, and a rear surface 2B arranged separate from the front surface 2A in a front-and-rear direction; a paper feed tray 10 that supports a sheet S; an image forming unit 5 that transfers toner to the sheet S fed from the paper feed tray 10 to form an image; a drawer 59 that includes a resist roller 35a correcting the inclination of the sheet S, supports a toner cartridge 50, and is movable along a direction directed from the rear surface 2B to the front surface 2A through the front opening 2F in the apparatus body 2; and a re-conveying chute 13 that forms a re-conveying path P2 for guiding the sheet S on one side of which the image is formed by the image forming unit 5 to the image forming unit 5 again. The re-conveying path P2 is located between the paper feed tray 10 and the drawer 59 in an up-down direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Conventionally, image forming devices such as color laser printers have been known that include multiple toner cartridges containing developers of different colors and an image forming unit that transfers the developers to a sheet to form an image.

[0003] In recent years, it has become desirable to extend the life of such image forming devices by configuring each component of the device as a unit that can be replaced. For example, in the image forming device disclosed in Patent Document 1, multiple toner cartridges are supported by a drawer that is detachable from the main body of the image forming device, and the toner cartridges are configured to be replaceable by pulling the drawer out of the main body. In addition, the drawer supports registration rollers that correct the skew of sheets fed toward the image forming unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-25200 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, if the drawer supporting the registration roller is configured to be detachable from the main body, the positional accuracy of the drawer relative to the main body when attached to the main body may be reduced compared to when the drawer is fixed so that it cannot be detached from the main body, which may reduce the registration roller's ability to correct sheet inclination.

[0006] In particular, in the image forming apparatus disclosed in Patent Document 1, the re-conveyance path that guides a sheet, one side of which has an image formed by the image forming unit, back to the image forming unit is located below the paper feed tray that supports the sheets fed toward the image forming unit. This increases the length of the re-conveyance path, which tends to reduce the accuracy of skew correction by the registration rollers for the sheet transported along the re-conveyance path.

[0007] Therefore, the present invention provides an image forming apparatus that can maintain the sheet skew correction function of the registration rollers even when the drawer is configured to be removable from the main body. [Means for solving the problem]

[0008] The image forming apparatus that solves the above problem has the following features.

[0009] That is, the image forming device comprises a main body having a first side wall with a first opening and a second side wall spaced apart from the first side wall in a first direction, a paper feed tray that supports a sheet, an image forming unit that transfers developer to a sheet fed from the paper feed tray to form an image, a drawer that has a registration roller that corrects the inclination of the sheet, supports a cartridge that contains developer, and is movable through the first opening of the main body along a direction from the second side wall to the first side wall, and a re-conveying chute that forms a re-conveying path that guides a sheet that has an image formed on one side by the image forming unit back to the image forming unit, and the re-conveying path is located between the paper feed tray and the drawer in the vertical direction.

[0010] If the drawer attached to the main body is movable in the direction from the second side wall toward the first side wall, the positional accuracy of the drawer attached to the main body relative to the main body may be reduced compared to when the drawer is fixed to the main body. If the positional accuracy of the drawer relative to the main body is reduced, the sheet skew correction function of the registration rollers provided in the drawer may be reduced. However, by locating the re-conveyance path between the paper feed tray and the drawer, the length of the re-conveyance path can be shortened compared to when the re-conveyance path is located below the paper feed tray. This allows the skew correction function of the registration rollers for sheets transported along the re-conveyance path to be maintained.

[0011] The second side wall also has a second opening, and the re-conveying chute attached to the main body is movable through the second opening in a direction from the first side wall to the second side wall.

[0012] As a result, the direction of movement of the re-conveying chute when it is pulled out from the main body is opposite to the direction of movement when the drawer is pulled out from the main body, so that the re-conveying chute can be pulled out from the main body without interfering with the pulling out of the drawer.

[0013] The fixing device further includes a heating rotor and a pressure rotor, and is detachable from the main body, the second side wall having a third opening, and the fixing device attached to the main body is movable through the third opening along the direction from the first side wall to the second side wall.

[0014] As a result, the direction of movement when the fixing device is pulled out from the main body is opposite to the direction of movement when the drawer is pulled out from the main body, so the fixing device can be pulled out from the main body 2 without interfering with the pulling out of the drawer.

[0015] The drawer and the fixing device are at least partially overlapped in the vertical direction.

[0016] This reduces the vertical space occupied by the drawer and the fixing device, allowing the main body to be made smaller in size in the vertical direction.

[0017] The second side wall also has a cover that can be moved between an open position that opens the third opening and a closed position that closes the opening, and when moved to the open position, the cover is in a position that does not interfere with the movement trajectory of the fixing device.

[0018] This allows the fixing device to be smoothly pulled out from the main body without being obstructed.

[0019] The second side wall is movable between an open position that opens the third opening and a closed position that closes the opening, and is provided with a cover that forms a flow path through which air flows when in the closed position, and the fixing device is provided with a handle for moving the fixing device, and the flow path and the handle overlap when viewed from the axial direction of the pressure rotating body in the fixing device.

[0020] This allows the main body to be made smaller in size in the first direction than when the handle and the flow path are arranged offset from each other in the first direction, which is the direction of movement of the fixing device.

[0021] The fixing device also includes a fixing separation gear for separating the pressure rotating body from the heating rotating body, a paper discharge drive gear for driving a fixing paper discharge roller arranged downstream of the heating rotating body and the pressure rotating body in the sheet transport direction, and a fixing drive gear for driving the heating rotating body, and the fixing separation gear, the paper discharge drive gear, and the fixing drive gear are positioned in this order from top to bottom.

[0022] This allows the discharge drive gear and the fixing drive gear to be positioned closer to each other than when the discharge drive gear, the fixing separation gear, and the fixing drive gear are positioned in that order from top to bottom, thereby simplifying the configuration of the gear train for transmitting driving force from the drive source to the fixing drive gear and the discharge drive gear.

[0023] The printer also includes a main body having a first side wall with a first opening and a second side wall spaced apart from the first side wall in a first direction, a paper feed tray that supports sheets, an image forming unit that transfers developer to a sheet fed from the paper feed tray to form an image, a drawer that supports a cartridge that contains developer and is movable through the first opening of the main body along a direction from the second side wall to the first side wall, and a re-conveying chute that forms a re-conveying path that guides a sheet that has an image formed on one side by the image forming unit back to the image forming unit, and the re-conveying path is located between the paper feed tray and the drawer in the vertical direction.

[0024] This allows the drawer to be pulled out of the main body through the first opening without interfering with the re-feed chute.

[0025] The second side wall also has a second opening, and the re-conveying chute attached to the main body is movable through the second opening in a direction from the first side wall to the second side wall.

[0026] As a result, the direction of movement of the re-conveying chute when it is pulled out from the main body is opposite to the direction of movement when the drawer is pulled out from the main body, so that the re-conveying chute can be pulled out from the main body without interfering with the pulling out of the drawer.

[0027] The fixing device further includes a heating rotor and a pressure rotor, and is detachable from the main body, the second side wall having a third opening, and the fixing device attached to the main body is movable through the third opening along the direction from the first side wall to the second side wall.

[0028] As a result, the direction of movement when the fixing device is pulled out from the main body is opposite to the direction of movement when the drawer is pulled out from the main body, so the fixing device can be pulled out from the main body 2 without interfering with the pulling out of the drawer.

[0029] The drawer and the fixing device are at least partially overlapped in the vertical direction.

[0030] This reduces the vertical space occupied by the drawer and the fixing device, and allows the main body of the image forming apparatus to be made smaller in size in the vertical direction.

[0031] The drawer also includes a conveying roller for conveying the sheet.

[0032] By positioning the re-conveyance path between the paper feed tray and the drawer, the length of the re-conveyance path is shortened, and it is possible to prevent a decrease in the sheet conveyance function of the conveyance roller. [Effects of the Invention]

[0033] According to the present invention, it is possible to maintain the inclination correction function of the registration roller with respect to the sheet transported along the re-transport path. [Brief explanation of the drawings]

[0034] [Figure 1] 2 is a central cross-sectional view showing the image forming apparatus with the front cover and rear cover in the closed position. FIG. [Figure 2] 2 is a central cross-sectional view showing the image forming apparatus with the front cover and rear cover in the open position. FIG. [Figure 3] 2 is a perspective view of the image forming apparatus when viewed from the front side with the front cover and the rear cover in the closed position. FIG. [Figure 4] 2 is a perspective view of the image forming apparatus as seen from the front side with the front cover and rear cover in the open position. FIG. [Figure 5] FIG. 2 is a perspective view of the image forming apparatus as seen from the rear side with the front cover and rear cover in the closed position. [Figure 6] FIG. 2 is a perspective view of the image forming apparatus as seen from the rear side with the front cover and rear cover in the open position. [Figure 7] FIG. 2 is a perspective view of the fixing device as seen from the front. [Figure 8] FIG. 2 is a perspective view of the fixing device as seen from the rear. [Figure 9] 10 is a side view showing the positional relationship between a fixing drive gear, a paper discharge drive gear, and a fixing separation gear 83 provided in the fixing device. FIG. [Figure 10] 1A and 1B are side cross-sectional views showing a mechanism for switching the fixing device between a pressure-contact state and a separation state, in which FIG. 1A shows the fixing device in the pressure-contact state, and FIG. 1B shows the fixing device in the separation state. DETAILED DESCRIPTION OF THE INVENTION

[0035] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0036] [Image forming device] The image forming apparatus 1 shown in FIGS. 1 to 6 is one embodiment of the image forming apparatus according to the present invention, and is a color laser printer that forms a multicolor image on a sheet S by electrophotography.

[0037] In the following description, the left side in Fig. 1 is defined as the front side of the image forming apparatus 1, the right 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 right side of the image forming apparatus 1, and the back side of the paper in Fig. 1 is defined as the left 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.

[0038] The image forming apparatus 1 includes a device main body 2, a paper feed unit 3 including a paper feed tray 10 that supports sheets S and a sheet conveying unit 30 that conveys the sheets S, and an image forming unit 5 that forms an image on the sheets S conveyed by the paper feed unit 3. The device main body 2 is an example of a main body.

[0039] The device body 2 is formed in a substantially rectangular parallelepiped shape and houses the paper feed unit 3 and the image forming unit 5. The device body 2 has a front surface 2A. A front opening 2F is opened in the front surface 2A of the device body 2, and the device body 2 has a front cover 21 that can open and close the front opening 2F. The front surface 2A is an example of a first side wall. The front opening 2F is an example of a first opening provided in the first side wall.

[0040] The front cover 21 is configured to be rotatable around a rotation shaft 21a at its lower end, and by rotating around the rotation shaft 21a, it can be moved between a closed position (position shown in FIGS. 1 and 3) where the front opening 2F is closed and an open position (position shown in FIGS. 2 and 4) where the front opening 2F is open. A paper output tray 22 is formed on the top surface of the device body 2, sloping downward from the front to the rear.

[0041] The device body 2 has a rear surface 2B. The rear surface 2B is disposed at a distance from the front surface 2A in the front-rear direction. The front-rear direction is an example of a first direction. A first rear opening 2Ra is opened on the rear surface 2B of the device body 2, and the device body 2 has a rear cover 23 that can open and close the first rear opening 2Ra. The rear surface 2B of the device body 2 is an example of a second side wall, and the first rear opening 2Ra is an example of a third opening provided in the second side wall.

[0042] The rear cover 23 is configured to be rotatable about a rotation shaft 23a at its lower end, and by rotating about the rotation shaft 23a, it can be moved between a closed position (position shown in FIGS. 1 and 5) where the first rear opening 2Ra is closed, and an open position (position shown in FIGS. 2 and 6) where the first rear opening 2Ra is opened. The rear cover 23 is an example of a cover that can be moved between an open position where the third opening is opened, and a closed position where the third opening is closed.

[0043] The paper feed unit 3 is disposed at the bottom of the device body 2, and conveys the sheets S supported on the paper feed tray 10 to the image forming unit 5 by the sheet conveying unit 30. The paper feed tray 10 supports the sheets S to be fed toward the image forming unit 5. 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.

[0044] The sheet conveying section 30 includes a paper feed roller 32, a separation roller 33, a separation pad 33a, a conveying roller pair 34, a registration roller 35a, and a driven roller 35b. The driven roller 35b is disposed opposite the registration roller 35a. Within the device main body 2, a conveying path P1 for the sheet S is configured, which runs from the paper feed tray 10 to the paper discharge tray 22 via the image forming section 5.

[0045] The sheets S supported on the paper feed tray 10 are separated one by one by the paper feed roller 32, the separation roller 33, and the separation pad 33a and sent to the conveying path P1. 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 the separation pad 33a constitute a separating means that separates the sheets S supported on the paper feed tray 10 one by one.

[0046] The sheet S sent to the conveying path P1 is conveyed toward the image forming unit 5 by the pair of conveying rollers 34, the registration roller 35a, and the driven roller 35b.

[0047] The registration rollers 35a regulate the movement of the leading edge of the sheet S being transported from the paper feed tray 10 toward the image forming unit 5, temporarily stop the sheet S, correct any skew of the sheet S, and then transport the sheet S at a predetermined timing toward the image forming unit 5. The registration rollers 35a are rollers for correcting the skew of the sheet S being fed from the paper feed tray 10 toward the image forming unit 5. The registration rollers 35a are an example of a transport roller that transports a sheet.

[0048] The image forming unit 5 is disposed above the paper feeding unit 3, and includes four toner cartridges 50 arranged side by side in the front-to-rear direction, and a photosensitive drum 51 corresponding to each toner cartridge 50. The toner cartridges 50 and photosensitive drums 51 are disposed to correspond to the colors yellow, magenta, cyan, and black.

[0049] The image forming unit 5 includes a drawer 59. The toner cartridge 50 is detachably supported by the drawer 59. The registration roller 35a is also supported by the drawer 59.

[0050] The drawer 59 is detachably supported on the device body 2. The drawer 59 can be attached to and detached from the device body 2 through a front opening 2F of the device body 2 by opening the front cover 21.

[0051] Drawer 59 attached to device body 2 is configured to be movable through front opening 2F in the direction from rear surface 2B to front surface 2A. In other words, drawer 59 attached to device body 2 is movable forward through front opening 2F.

[0052] Drawer 59 has a handle 591 at its front end for moving drawer 59. When drawer 59 attached to device main body 2 is to be moved forward, handle 591 can be grasped and pulled forward to move drawer 59.

[0053] With the front cover 21 in the open position, the drawer 59 attached to the device body 2 can be moved forward through the front opening 2F to pull out and remove the drawer 59 from the device body 2. In this case, the front cover 21 moved to the open position is in a position that does not interfere with the movement trajectory of the drawer 59 moving in the front-to-rear direction.

[0054] Therefore, when the drawer 59 is moved forward through the front opening 2F, the movement of the drawer 59 is not impeded, and the drawer 59 can be smoothly pulled out from the device body 2. Also, when the drawer 59 is moved backward through the front opening 2F, the movement of the drawer 59 is not impeded, and the drawer 59 can be smoothly attached to the device body 2.

[0055] The toner cartridge 50 contains toner. Toner is an example of a developer. The toner cartridge 50 is equipped with a developing roller 52. The photosensitive drum 51 is formed in a substantially cylindrical shape with its axis in the left-right direction, and is rotatably supported by a drawer 59. The developing roller 52 extends in the left-right direction, and is rotatably supported by the toner cartridge 50. The developing roller 52 supplies toner to the photosensitive drum 51.

[0056] The four photosensitive drums 51 provided in the image forming unit 5 will be referred to as follows, as appropriate, as necessary: ​​the photosensitive drum 51 corresponding to yellow, which is arranged most upstream in the sheet transport direction, is the first photosensitive drum 51Y; the photosensitive drum 51 corresponding to magenta, which is arranged downstream of the first photosensitive drum 51Y in the sheet transport direction, is the second photosensitive drum 51M; the photosensitive drum 51 corresponding to cyan, which is arranged downstream of the second photosensitive drum 51M in the sheet transport direction, is the third photosensitive drum 51C; and the photosensitive drum 51 corresponding to black, which is arranged downstream of the third photosensitive drum 51C in the sheet transport direction, is the fourth photosensitive drum 51K.

[0057] The apparatus main body 2 has an exposure device 56 that exposes the surfaces of the photosensitive drums 51. The exposure device 56 includes a laser diode, a polarizer, a lens, a mirror, etc. The exposure device 56 is configured to emit a light beam toward each photosensitive drum 51 to expose the surface of each photosensitive drum 51.

[0058] The exposure device 56 includes a first scanning unit 561Y that scans the surface of the first photosensitive drum 51Y with a light beam, a second scanning unit 561M that scans the surface of the second photosensitive drum 51M with a light beam, a third scanning unit 561C that scans the surface of the third photosensitive drum 51C with a light beam, and a fourth scanning unit 561K that scans the surface of the fourth photosensitive drum 51K with a light beam. Thus, the exposure device 56 includes four scanning units 561Y, 561M, 561C, and 561K that correspond to the photosensitive drums 51Y, 51M, 51C, and 51K, respectively.

[0059] A transfer belt 41 is disposed below and facing the photosensitive drum 51 across the transport path P1. The transfer belt 41 is in contact with the photosensitive drum 51. The transfer belt 41 is stretched between a drive roller 42 and a driven roller 43 disposed in front of the drive roller 42. 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 transfer belt 41, the drive roller 42, the driven roller 43, the transfer roller 44, etc. form a belt device 40.

[0060] The image forming unit 5 includes a charger 54 for charging each photosensitive drum 51. The charger 54 is supported by a drawer 59. The photosensitive drums 51 are uniformly charged by the charger 54 and are selectively exposed to light by an exposure device 56. This exposure selectively removes charge from the surface of the photosensitive drum 51, and an electrostatic latent image is formed on the surface of the photosensitive drum 51.

[0061] The toner contained in the toner cartridge 50 is positively charged and 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.

[0062] 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 photosensitive drum 51 faces the sheet S, the toner image carried on the surface of the photosensitive drum 51 is transferred onto the sheet S by a transfer bias applied to the transfer roller 44. In this way, the image forming unit 5 transfers toner onto the sheet S fed from the paper feed tray 10 to form an image.

[0063] 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.

[0064] The sheet S onto which the toner image has been transferred is transported to a fixing device 60. The fixing device 60 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 an example of a heating rotator, and the pressure roller 62 is an example of a pressure rotator. The heating roller 61 and the pressure roller 62 are disposed in such a manner that their axial directions are aligned with the left-right direction. The left-right direction is the axial direction of the heating roller 61 and the pressure roller 62.

[0065] The toner image is thermally fixed onto the sheet S conveyed to the fixing device 60 while the sheet S passes between a heating roller 61 and a pressure roller 62. In other words, the fixing device 60 fixes the toner image onto the sheet S. The fixing device 60 is detachably mounted on the apparatus main body 2.

[0066] The fixing device 60 includes a fixing and ejecting roller 65a and a roller 65b, which are disposed downstream in the sheet conveying direction from the heating roller 61 and the pressure roller 62. The roller 65b is disposed opposite the fixing and ejecting roller 65a.

[0067] The sheet S on which the toner image has been thermally fixed is conveyed downstream in the sheet conveying direction from the heating roller 61 and the pressure roller 62 by the fixing and paper discharge roller 65a and the roller 65b.

[0068] Downstream in the sheet conveying direction of fixing discharge rollers 65a and 65b are disposed intermediate discharge rollers 68a and driven rollers 68b arranged opposite intermediate discharge rollers 68a. Downstream in the sheet conveying direction of intermediate discharge rollers 68a and driven rollers 68b are disposed discharge rollers 69a and driven rollers 69b arranged opposite discharge rollers 69a.

[0069] The sheet transported downstream of the fixing discharge rollers 65a and 65b in the sheet transport direction is transported by the intermediate discharge rollers 68a and driven rollers 68b, and further transported by the discharge rollers 69a and driven rollers 69b, and discharged onto the discharge tray 22.

[0070] In the image forming apparatus 1, a process unit PU that forms a toner image on a sheet S is configured by a drawer 59, a toner cartridge 50 supported by the drawer 59, a photosensitive drum 51, a charger 54, etc. The process unit PU is only required to include at least the photosensitive drum 51 and the charger 54, and may also include a transfer belt 41 or a fixing device 60.

[0071] The image forming apparatus 1 includes a power supply board 11 on which a power supply circuit is formed, and a board cover 12 that covers the power supply board 11. The board cover 12 is formed from a conductive sheet metal member and is grounded. The board cover 12 is disposed between the paper feed tray 10 and the belt device 40 and fixing device 60 in the vertical direction. The apparatus main body 2 houses the process unit PU and the board cover 12.

[0072] The discharge roller 69a and the intermediate discharge roller 68a are configured to be rotatable in a forward direction, which is the rotation direction when transporting the sheet S toward the discharge tray 22 side, and a reverse direction, which is the rotation direction opposite to the forward direction.

[0073] The image forming apparatus 1 has a re-conveying path P2 that guides the sheet S, which has been conveyed along the conveying path P1 and passed through the fixing device 6, to the conveying path P1 upstream of the registration rollers 35a in the sheet conveying direction. The re-conveying path P2 guides the sheet S, for example, on one side of which an image has been formed by the image forming unit 5, to the image forming unit 5 again.

[0074] The re-conveying path P2 branches off from the conveying path P1 at a branching point Pb located between the fixing discharge roller 65a and the intermediate discharge roller 68a, then extends forward between the substrate cover 12 and the paper feed tray 10, and merges with the conveying path P1 at a junction point Pa located between the conveying roller pair 34 and the registration roller 35a.

[0075] The sheet S transported from the fixing device 6 to the discharge roller 69a can be transported again to the image forming unit 5 through the re-transport path P2 by rotating the discharge roller 69a and the intermediate discharge roller 68a in the reverse direction.

[0076] The sheet S transported to the re-conveying path P2 by the discharge roller 69a and the intermediate discharge roller 68a is transported toward the image forming unit 5 by the first re-conveying roller pair 36 and the second re-conveying roller pair 37 provided on the re-conveying path P2.

[0077] The image forming apparatus 1 includes a re-conveyance chute 13 that forms the re-conveyance path P2. The re-conveyance chute 13 is located between the paper feed tray 10 and the board cover 12 in the vertical direction.

[0078] The re-conveying chute 13 is disposed below the re-conveying path P2 formed between the paper feed tray 10 and the substrate cover 12. The re-conveying chute 13 has a guide surface 13a that guides the lower surface of the sheet being conveyed along the re-conveying path P2.

[0079] The image forming apparatus 1 is capable of double-sided printing, in which a sheet S, on one side of which an image has been formed in the image forming unit 5, is transported again to the image forming unit 5 via a re-transport path P2, and an image is formed on the other side of the sheet S.

[0080] [Vertical position of re-transport path] The re-conveying path P2 formed by the re-conveying chute 13 is located between the paper feed tray 10 and the drawer 59 in the vertical direction. In other words, the re-conveying path P2 is located above the paper feed tray 10, and the drawer 59 is located above the re-conveying path P2.

[0081] If the drawer 59 supporting the registration rollers 35a is configured to be detachable from the device body 2 and the drawer 59 attached to the device body 2 can be moved forward, the positional accuracy of the drawer 59 attached to the device body 2 with respect to the device body 2 may be reduced compared to when the drawer 59 is fixed so as not to be detachable from the device body 2. If the positional accuracy of the drawer 59 with respect to the device body 2 is reduced, the function of correcting the skew of the sheet S and the function of conveying the sheet S by the registration rollers 35a may be reduced.

[0082] However, by arranging the re-conveying path P2 between the paper feed tray 10 and the drawer 59, the length of the re-conveying path P2 can be made shorter than when the re-conveying path P2 is arranged below the paper feed tray 10. This makes it possible to maintain the tilt correction function of the registration roller 35a for the sheet S transported along the re-conveying path P2. In addition, because the distance between the registration roller 35a and the first re-conveying roller pair 36 of the re-conveying path P2 is shortened, it is possible to suppress a decrease in the transport function of the sheet S.

[0083] In addition, in the image forming apparatus 1, when an image is being formed on a first sheet S fed from the paper feed tray 10 to the image forming section 5, a second sheet S with an image formed on one side can be retained in the re-conveying path P2, and an image can be formed on the other side of the second sheet S immediately after the image is formed on the first sheet S.

[0084] In this way, when sheets S are retained on the re-conveying path P2 and continuous printing is performed on multiple sheets S, the speed of continuous printing can be increased by locating the re-conveying path P2 between the paper feed tray 10 and the drawer 59 and shortening the length of the re-conveying path P2.

[0085] Furthermore, since the drawer 59 is located above the re-conveying path P2, when the drawer 59 is pulled out from the device main body 2 through the front opening 2F, the drawer 59 can be pulled out from the device main body 2 without interfering with the re-conveying chute 13.

[0086] [Drawer variation] In this embodiment, the drawer 59 is described as being equipped with the registration rollers 35a, but the drawer 59 may not be equipped with the registration rollers 35a, and the registration rollers 35a may be supported by other members of the device body 2. Even in this case, when the drawer 59 is pulled out of the device body 2 through the front opening 2F, it can be pulled out of the device body 2 without interfering with the re-conveyance chute 13.

[0087] [Re-conveyance chute movement direction] The re-conveying chute 13 is detachably attached to the device main body 2. A second rear opening 2Rb is formed in the rear surface 2B of the device main body 2. The second rear opening 2Rb is an example of a second opening provided in the second side wall. The second rear opening 2Rb is located below the first rear opening 2Ra.

[0088] In this embodiment, the first rear opening 2Ra and the second rear opening 2Rb are formed as one continuous opening. However, the first rear opening 2Ra and the second rear opening 2Rb may be separated by a frame or the like, and the first rear opening 2Ra and the second rear opening 2Rb may be formed as separate openings.

[0089] The re-conveying chute 13 attached to the device body 2 is movable through the second rear opening 2Rb in the direction from the front surface 2A to the rear surface 2B. In other words, the re-conveying chute 13 attached to the device body 2 is movable rearward through the second rear opening 2Rb.

[0090] By moving the re-conveying chute 13 attached to the device body 2 toward the rear, it is possible to pull out and remove the re-conveying chute 13 from the device body 2. As shown in Fig. 5, the re-conveying chute 13 attached to the device body 2 can be pulled out toward the rear from the device body 2 through the second rear opening 2Rb when the rear cover 23 is in the closed position.

[0091] In this way, in the image forming apparatus 1, the drawer 59 is configured to be pulled forward from the device main body 2 and removed, while the re-conveying chute 13 is configured to be pulled backward from the device main body 2 and removed.

[0092] As a result, the direction of movement of the re-conveying chute 13 when it is pulled out from the device body 2 is opposite to the direction of movement of the drawer 59 when it is pulled out from the device body 2, so it is possible to pull out the re-conveying chute 13 from the device body 2 without interfering with the pulling out of the drawer 59. Similarly, it is possible to pull out the drawer 59 from the device body 2 without interfering with the pulling out of the re-conveying chute 13.

[0093] Furthermore, when the re-conveying chute 13 is attached to the device body 2, the re-conveying chute 13 can be moved forward through the second rear opening 2Rb without interfering with the drawer 59. Similarly, when the drawer 59 is attached to the device body 2, the drawer 59 can be moved rearward through the front opening 2F without interfering with the re-conveying chute 13.

[0094] [Movement direction of the fixing unit] 2 and 6, when the rear cover 23 is in the open position, the fixing device 60 is exposed to the outside of the apparatus body 2 through the first rear opening 2Ra. When the rear cover 23 is in the open position, the fixing device 60 is detachable from the apparatus body 2 through the first rear opening 2Ra.

[0095] The fixing device 60 attached to the apparatus main body 2 is movable through the first rear opening 2Ra in the direction from the front surface 2A to the rear surface 2B. In other words, the fixing device 60 attached to the apparatus main body 2 is movable rearward through the first rear opening 2Ra.

[0096] When the rear cover 23 is in the open position, the fixing device 60 attached to the device main body 2 can be moved rearward, allowing the fixing device 60 to be pulled out and removed from the device main body 2 through the first rear opening 2Ra.

[0097] In this way, in the image forming apparatus 1, the drawer 59 is configured to be removed by pulling it out toward the front from the apparatus main body 2, whereas the fixing device 60 is configured to be removed by pulling it out toward the rear from the apparatus main body 2.

[0098] As a result, the direction of movement when the fixing device 60 is pulled out from the device body 2 is opposite to the direction of movement when the drawer 59 is pulled out from the device body 2, so that the fixing device 60 can be pulled out from the device body 2 without interfering with the pulling out of the drawer 59. Similarly, the drawer 59 can be pulled out from the device body 2 without interfering with the pulling out of the fixing device 60.

[0099] Furthermore, when the fixing device 60 is attached to the apparatus main body 2, the fixing device 60 can be moved forward through the first rear opening 2Ra without interfering with the drawer 59. Similarly, when the drawer 59 is attached to the apparatus main body 2, the drawer 59 can be moved rearward through the front opening 2F without interfering with the fixing device 60.

[0100] [Positional relationship between the drawer and the fixing unit] 1, drawer 59 and fixing device 60 are disposed in a position where they at least partially overlap in the vertical direction. That is, drawer 59 and fixing device 60 have portions located at the same height, and overlap when viewed in the horizontal direction perpendicular to the vertical direction.

[0101] This reduces the vertical space occupied by the drawer 59 and the fixing device 60, making it possible to reduce the size of the device body 2 of the image forming device 1 in the vertical direction.

[0102] [Relationship between the fixing unit movement path and the rear cover] 2 and 6, when the rear cover 23 is in the open position, the fixing device 60 can be moved in the front-to-rear direction to be attached to or detached from the apparatus main body 2. In this case, the rear cover 23 moved to the open position is in a position that does not interfere with the movement trajectory of the fixing device 60 moving in the front-to-rear direction.

[0103] Therefore, when the fixing device 60 is moved in the forward and backward directions to be attached to or detached from the device main body 2, the fixing device 60 can be smoothly pulled out from and attached to the device main body 2 without being hindered.

[0104] [Positional relationship between rear cover and fuser unit handle] 1 and 6, the rear cover 23 has a plurality of ribs 231. The ribs 231 extend from the side closer to the rotation shaft 23a to the side farther from the rotation shaft 23a. When the rear cover 23 is in the closed position, the ribs 231 extend in the vertical direction.

[0105] When the rear cover 23 is in the closed position, the rib 231 protrudes forward from the inner surface 23A of the rear cover 23. The inner surface 23A is the surface that faces the fixing device 60 when the rear cover 23 is in the closed position. A plurality of ribs 231 are arranged at intervals along the left-right direction.

[0106] The ribs 231 form a transport path P1 when the rear cover 23 is in the closed position, and guide the sheet S transported from the fixing device 60 toward the discharge tray 22. A flow path FP through which air flows when the rear cover 23 is in the closed position is formed between the ribs 231 arranged side by side on the left and right.

[0107] 1 and 5, the device body 2 is provided with a fan 7 for discharging air from inside the device body 2 to the outside. When the rear cover 23 is in the closed position, the fan 7 is driven, causing air to flow from below to above within the flow path FP. In other words, the rear cover 23 forms a flow path FP through which air flows when the rear cover 23 is in the closed position.

[0108] 1, 7, and 8, the fixing device 60 includes a fixing cover 63 that covers the periphery of the heating roller 61 and the pressure roller 62, and a handle 64 for moving the fixing device 60. The handle 64 protrudes rearward from both left and right ends of the fixing cover 63. When moving the fixing device 60 attached to the device main body 2 rearward, the fixing device 60 can be moved by grasping the handle 64 and pulling it rearward.

[0109] 1, when the rear cover 23 is in the closed position, the rear end of the handle 64 of the fixing device 60 is located behind the front end of the rib 231. Therefore, the handle 64 of the fixing device 60 and the rib 231 of the rear cover 23 overlap when viewed from the left and right. Also, the handle 64 of the fixing device 60 and the flow path FP of the rear cover 23 overlap when viewed from the left and right.

[0110] In this way, by configuring the handle 64 and the flow path FP so that they overlap when viewed from the left and right, the device main body 2 can be made smaller in the front-to-back direction compared to when the handle 64 and the flow path FP are arranged offset in the front-to-back direction, which is the movement direction of the fixing device 60.

[0111] [Positional relationship of the fixing device gears] 7 to 9, the fixing device 60 includes a fixing drive gear 81, a paper discharge drive gear 82, and a fixing separation gear 83. The fixing drive gear 81, the paper discharge drive gear 82, and the fixing separation gear 83 are located at the left end of the fixing device 60.

[0112] The fixing drive gear 81 is a gear for driving the heating roller 61. The fixing drive gear 81 is rotatable integrally with the heating roller 61. The paper discharge drive gear 82 is a gear for driving the fixing paper discharge roller 65a. The paper discharge drive gear 82 is rotatable integrally with the fixing paper discharge roller 65a.

[0113] Fixing device 60 is configured to be switchable between a pressure-contact state in which heating roller 61 and pressure roller 62 are in pressure contact with each other, and a separation state in which heating roller 61 and pressure roller 62 are separated from each other. Fixing separation gear 83 is a gear for separating pressure roller 62 from heating roller 61, thereby switching fixing device 60 from the pressure-contact state to the separation state.

[0114] 9 and 10, the fixing separation gear 83 is fixed to a gear shaft 83a. A separation cam 88 is fixed to the gear shaft 83a. The fixing separation gear 83 and the separation cam 88 are configured to be rotatable integrally.

[0115] The fixing device 60 includes a pivot arm 91 that supports the pressure roller 62. The pivot arm 91 is supported by the fixing cover 63 so as to be pivotable about a pivot fulcrum 91a. An abutment portion 92 that can abut against the separation cam 88 is provided at the end of the pivot arm 91 opposite to the pivot fulcrum 91a side across the fixing cover 63.

[0116] In the fixing device 60, the rotation of the rotary arm 91 about the rotation fulcrum 91a switches the state between a pressure contact state in which the pressure roller 62 is in pressure contact with the heat roller 61 and a separation state in which the pressure roller 62 is separated from the heat roller 61. The pressure roller 62 is biased in the direction of pressure contact with the heat roller 61 by a biasing member.

[0117] 10(a), when the fixing device 60 is in the pressed state, the separation cam 88 is in a rotational position where it is separated from the contact portion 92 of the rotating arm 91. As shown in FIG. 10(b), when the fixing separation gear 83 is driven and rotated from this state, the separation cam 88 rotates integrally with the fixing separation gear 83 and comes into contact with the contact portion 92 of the rotating arm 91.

[0118] The separating cam 88 abutting against the abutting portion 92 of the rotating arm 91 presses the rotating arm 91 in the direction in which the pressure roller 62 and the heat roller 61 are separated from each other, and the pressure roller 62 is separated from the heat roller 61 .

[0119] On the other hand, when the fixing device 60 is in the separated state, the fixing separation gear 83 is driven to rotate, and the separation cam 88, which rotates integrally with the fixing separation gear 83, separates from the contact portion 92 of the rotating arm 91. When the separation cam 88 separates from the contact portion 92 of the rotating arm 91, the pressure roller 62 is pressed against the heating roller 61 by the biasing force of the biasing member, and the fixing device 60 switches to the pressed state.

[0120] 9, the fixing device 60 includes an input gear 84 that meshes with the fixing drive gear 81. The input gear 84 is a gear that inputs a driving force from a drive source to the fixing drive gear 81.

[0121] The fixing device 60 includes a first intermediate gear 85 that meshes with the fixing drive gear 81, and a second intermediate gear 86 that meshes with the first intermediate gear 85. The paper discharge drive gear 82 meshes with the second intermediate gear 86.

[0122] The fixing drive gear 81, to which the driving force is input from the input gear 84, drives the heating roller 61. The driving force input to the fixing drive gear 81 is also transmitted to the paper discharge drive gear 82 via a first intermediate gear 85 and a second intermediate gear 86. The paper discharge drive gear 82, to which the driving force is transmitted, drives the fixing paper discharge roller 65a.

[0123] Both the heating roller 61 and the fixing discharge roller 65a are driven by the driving force input from the input gear 84, and the fixing drive gear 81, the first intermediate gear 85, the second intermediate gear 86, and the discharge drive gear 82 form a gear train for driving the heating roller 61 and the fixing discharge roller 65a.

[0124] The fixing device 60 includes an input gear 87 that meshes with the fixing separation gear 83. The input gear 87 is a gear that inputs a driving force from a drive source to the fixing separation gear 83. When the driving force from the input gear 87 is input to the fixing separation gear 83, the fixing separation gear 83 and a separation cam 88 rotate integrally, switching the fixing device 60 between a pressure contact state and a separation state.

[0125] The fixing drive gear 81, the paper discharge drive gear 82, and the fixing separation gear 83 are positioned in this order from top to bottom: fixing separation gear 83, paper discharge drive gear 82, and fixing drive gear 81.

[0126] By arranging the fixing separation gear 83, the paper discharge drive gear 82, and the fixing drive gear 81 in this order from top to bottom, the paper discharge drive gear 82 and the fixing drive gear 81 can be arranged closer to each other than when, for example, the paper discharge drive gear 82, the fixing separation gear 83, and the fixing drive gear 81 are arranged in this order from top to bottom. This simplifies the configuration of the gear train for transmitting driving force from the drive source to the fixing drive gear 81 and the paper discharge drive gear 82. [Explanation of symbols]

[0127] 1. Image forming device 2. Device body 2A front 2B Rear 2F front opening 2Ra 1st rear opening 2Rb 2nd rear opening 5. Image forming unit 10 Paper tray 13 Re-transport chute 23 Rear cover 35a Registration roller 50 toner cartridges 59 Drawer 60 Fixing device 61 Heating roller 62 Pressure roller 64 Handle 81 Fixing drive gear 82 Paper ejection drive gear 83 Fixing separation gear 231 Ribs FP flow path S seat

Claims

1. a main body including a first sidewall having a first opening and a second sidewall spaced apart from the first sidewall in a first direction; a paper feed tray for supporting the sheets; an image forming unit that transfers a developer onto a sheet fed from the paper feed tray to form an image; a drawer that includes a registration roller that corrects a skew of a sheet, supports a cartridge that contains a developer, and is movable through a first opening of the main body along a direction from the second side wall toward the first side wall; a re-conveyance chute that forms a re-conveyance path for guiding the sheet, one side of which has an image formed by the image forming unit, back to the image forming unit; Equipped with In the image forming apparatus, the re-conveyance path is located between the paper feed tray and the drawer in the vertical direction.

2. the second sidewall includes a second opening; 2. The image forming apparatus according to claim 1, wherein the re-feeding chute attached to the main body is movable through the second opening along a direction from the first side wall toward the second side wall.

3. a fixing device that is detachable from the main body and includes a heating rotor and a pressure rotor; the second sidewall includes a third opening; 3. The image forming apparatus according to claim 1, wherein the fixing device attached to the main body is movable through the third opening along a direction from the first side wall to the second side wall.

4. The image forming apparatus according to claim 3 , wherein the drawer and the fixing device are at least partially overlapped in the vertical direction.

5. the second side wall includes a cover that is movable between an open position that opens the third opening and a closed position that closes the third opening; 4. The image forming apparatus according to claim 3, wherein the cover, when moved to the open position, is in a position that does not interfere with the movement path of the fixing device.

6. the second side wall includes a cover that is movable between an open position that opens the third opening and a closed position that closes the third opening, and that forms a flow path through which air flows when the second side wall is in the closed position; the fixing device includes a handle for moving the fixing device; 4. The image forming apparatus according to claim 3, wherein the flow path and the handle overlap when viewed in the axial direction of the pressure rotating body of the fixing device.

7. The fixing device a fixing separation gear for separating the pressure rotating body from the heating rotating body; a sheet discharge drive gear for driving a fixing sheet discharge roller disposed downstream of the heating rotary member and the pressure rotary member in the sheet conveying direction; a fixing drive gear for driving the heating rotor, 4. The image forming apparatus according to claim 3, wherein the fixing separation gear, the paper discharge drive gear, and the fixing drive gear are positioned in this order from top to bottom.

8. a main body including a first sidewall having a first opening and a second sidewall spaced apart from the first sidewall in a first direction; a paper feed tray for supporting the sheets; an image forming unit that transfers a developer onto a sheet fed from the paper feed tray to form an image; a drawer that supports a cartridge containing a developer and is movable through a first opening of the main body along a direction from the second side wall toward the first side wall; a re-conveyance chute that forms a re-conveyance path for guiding the sheet, one side of which has an image formed by the image forming unit, back to the image forming unit; Equipped with In the image forming apparatus, the re-conveyance path is located between the paper feed tray and the drawer in the vertical direction.

9. the second sidewall includes a second opening; 9. The image forming apparatus according to claim 8, wherein the re-feeding chute attached to the main body is movable through the second opening along a direction from the first side wall toward the second side wall.

10. a fixing device that is detachable from the main body and includes a heating rotor and a pressure rotor; the second sidewall includes a third opening; 10. The image forming apparatus according to claim 8, wherein the fixing device attached to the main body is movable through the third opening along a direction from the first side wall to the second side wall.

11. The image forming apparatus according to claim 10 , wherein the drawer and the fixing device are at least partially overlapped in the vertical direction.

12. 9. The image forming apparatus according to claim 8, wherein the drawer includes a conveying roller for conveying a sheet.

Images