Image formation device

Abstract

To provide an image formation device that can have a circuit board easily repaired and replaced.SOLUTION: A re-carrying part 7 of an image formation device 1 has: a lower chute 71 which is located between a sheet tray 10 and a substrate case 12, and guides a sheet S; an upper chute 72 which is located downstream from the substrate case 12 in a re-carrying direction, and guides the sheet S together with the lower chute 71; and a screw 92 for fixing the upper chute 72 to a device body 2, wherein the upper chute 72 is rotatable between a first position where a re-carrying path P2 for the sheet S is formed together with the lower chute 71, and a second position which is rotated toward the lower chute 71 on a rotary shaft 722 relative to the first position, the rotary shaft 722 is located at a front end as a downstream-side end of the upper chute 72 in the re-carrying direction, and the screw 92 fixes a rear end as an upstream-side end of the upper chute 72 in the re-carrying direction to the device body 2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] As disclosed in Patent Document 1, there has been known an image forming apparatus equipped with a re-conveying section for re-conveying a sheet having an image formed on one side in an image forming section to the image forming section along a re-conveying direction.

[0003] The image forming apparatus described in Patent Document 1 includes an upper chute 62 that forms a re-conveyance path, a low-voltage circuit board 72 located downstream of the upper chute 62 in the re-conveyance direction, a sheet metal member 73 that houses the low-voltage circuit board 72, and a supply unit 41 that supplies sheets stored in a sheet tray to the image forming unit. The upper chute 62 is secured with screws at two locations, the sheet metal member 73 and the supply unit 41. The apparatus main body 2 that houses the upper chute 62, the low-voltage circuit board 72, the sheet metal member 73, the supply unit 41, etc., is configured so that the top is openable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-102434 Summary of the Invention [Problem to be solved by the invention]

[0005] In the image forming apparatus having the above-described configuration, when repairing or replacing the low-voltage circuit board 72, it was necessary to remove the drum unit 52, the belt conveying section 42, and the belt cleaner 54 housed in the device main body 2 from the device main body 2, thereby exposing the upper chute 62 and the sheet metal member 73 to the outside of the device main body 2.

[0006] To repair or replace the low-voltage circuit board 72, it was necessary to further remove the screws that fasten the upper chute 62 to the sheet metal member 73 and the supply unit 41, remove the upper chute 62 and the upper sheet metal 732 of the sheet metal member 73 from the device body 2, and then repair or replace the low-voltage circuit board 72 exposed to the outside of the device body 2. Therefore, repairing or replacing the low-voltage circuit board 72 was time-consuming and complicated.

[0007] Therefore, the present invention provides an image forming apparatus that reduces the time and effort required for repairing and replacing a circuit board, and allows the circuit board to be easily repaired and replaced. [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 apparatus comprises an apparatus main body, a sheet tray located at the lower end of the apparatus main body, an image forming unit located above the sheet tray and forming an image on a sheet, a re-conveying unit located between the image forming unit and the sheet tray and for re-conveying the sheet along a re-conveying direction to the image forming unit in order to form an image on the other side of the sheet having an image formed on one side by the image forming unit, a circuit board located between the image forming unit and the re-conveying unit, and a case having a case main body and a lid for accommodating the circuit board, the case being fixed to the apparatus main body in an orientation in which the lid is located closer to the re-conveying unit than the case main body, The conveying section has a lower chute located between the sheet tray and the case and guiding the sheet, an upper chute located downstream of the case in the re-conveying direction and guiding the sheet together with the lower chute, and a fixing device for fixing the upper chute to the device main body, wherein the upper chute is rotatable between a first position where it forms a re-conveying path for the sheet together with the lower chute, and a second position where it is rotated toward the lower chute around a rotation axis relative to the first position, the rotation axis being located at the downstream end of the upper chute in the re-conveying direction, and the fixing device fixing the upstream end of the upper chute in the re-conveying direction to the device main body.

[0010] This allows the circuit board to be repaired or replaced by rotating the upper chute from the first position to the second position and removing the cover while the upper chute and the case cover are exposed from the device body, thereby reducing the effort required to repair or replace the circuit board and making it easier to repair or replace the circuit board.

[0011] The image forming section has a photosensitive drum and an exposure unit that irradiates the photosensitive drum with laser light, and the exposure unit is fixed to an upper part of the apparatus main body.

[0012] In an image forming apparatus, since the exposure unit is fixed to the top of the apparatus body, it is not possible to open the top of the apparatus body to replace the circuit board. However, since the circuit board can be exposed on the bottom side of the apparatus body, the effort required for repairing and replacing the circuit board can be reduced and the repair and replacement of the circuit board can be easily performed.

[0013] The image forming unit has a plurality of photosensitive drums corresponding to images of a plurality of colors.

[0014] Therefore, if the top of the device body were opened to replace the circuit board, it would be necessary to remove multiple photosensitive drums from the device body, which would be cumbersome.On the other hand, in the image forming device, the circuit board can be exposed on the bottom side of the device body 2, which reduces the effort required to repair or replace the circuit board, making it easier to repair or replace the circuit board.

[0015] In addition, the device main body has a bearing hole that rotatably supports the rotating shaft of the upper chute, and the bearing hole is opened by an insertion opening that opens in a portion of the circumferential direction, and the rotating shaft can be inserted into the bearing hole through the insertion opening.

[0016] As a result, when attaching the upper chute to the device body, the rotating shaft can be easily supported by the bearing hole by inserting the rotating shaft into the bearing hole through the fitting opening.

[0017] In addition, the pivot axis has a first length in a first direction perpendicular to the axial direction of the pivot axis, and a second length smaller than the first length in a second direction perpendicular to the axial direction and the first direction, and the dimension of the insertion opening in the perpendicular direction perpendicular to the axial direction is larger than the second length and smaller than the first length.

[0018] This allows the rotating shaft to be inserted into the bearing hole with the first direction of the rotating shaft aligned with the direction from the insertion opening toward the bearing hole, and then the upper chute can be rotated into a position where the first direction of the rotating shaft intersects with the direction from the insertion opening toward the bearing hole, thereby preventing the rotating shaft from coming out of the bearing hole.

[0019] Furthermore, when the upper chute is in the second position, the first direction coincides with the direction from the insertion opening toward the bearing hole, and when the upper chute is in the first position, the first direction intersects with the direction from the insertion opening toward the bearing hole.

[0020] This allows the rotating shaft to be inserted into and removed from the bearing hole through the fitting opening when the upper chute is rotated to the second position. Also, when the upper chute is rotated to the first position, the rotating shaft inserted into the bearing hole can be prevented from coming out of the bearing hole. [Effects of the Invention]

[0021] According to the present invention, the time and effort required for repairing and replacing a circuit board can be reduced, and the circuit board can be easily repaired and replaced. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a central cross-sectional view showing the image forming apparatus. [Figure 2] FIG. 2 is a perspective view showing the device main body with the substrate case and the upper chute exposed. [Figure 3] FIG. 10 is a bottom view showing the device body with the substrate case and upper chute exposed. [Figure 4] FIG. 2 is a bottom view showing the device body with the cover of the board case removed. [Figure 5] FIG. [Figure 6] 10 is a side cross-sectional view showing the device body with the upper chute rotated to a first position. FIG. [Figure 7] 10 is a side cross-sectional view showing the device body with the upper chute rotated to a second position. FIG. [Figure 8] 1(a) is a side view showing a bearing hole of the first main body frame, and FIG. 1(b) is a side cross-sectional view showing the right rotation shaft of the upper chute. [Figure 9] 10 is a side cross-sectional view showing a state in which the upper chute is in a second position and the right rotation shaft of the upper chute is pulled out of the bearing hole of the first main body frame. FIG. [Figure 10] 10 is a side cross-sectional view showing a state in which the right rotation shaft of the upper chute, which is in a second position, is inserted into a bearing hole of the first main body frame. FIG. [Figure 11] 10 is a side cross-sectional view showing a state in which the right-hand rotation shaft is inserted into a bearing hole of the first main body frame and the upper chute is rotated to a first position. FIG. [Figure 12] 10 is a side cross-sectional view showing a state in which the left rotating shaft is inserted into the bearing hole of the second main body frame and the upper chute is rotated to a first position. FIG. [Figure 13] FIG. 2 is a perspective view showing a case body of the substrate case. [Figure 14] FIG. 2 is a perspective view showing a lid portion of a board case. [Figure 15] FIG. 10 is a side cross-sectional view showing the rear end of the upper chute fixed to the case body by a screw. DETAILED DESCRIPTION OF THE INVENTION

[0023] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0024] [Image forming device] An image forming apparatus 1 shown in FIG. 1 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.

[0025] 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.

[0026] The image forming device 1 comprises a device main body 2, a paper feed section 3 having a sheet tray 10 that supports sheets S and a sheet conveying section 30 that conveys sheets S, and an image forming section 5 that forms an image on sheets S conveyed by the paper feed section 3.

[0027] 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.

[0028] 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 where it closes the front opening 2F and an open position where it opens the front opening 2F. A paper output tray 22 is formed on the top surface of the device body 2, and is inclined downward from the front to the rear.

[0029] The paper feed unit 3 is disposed at the bottom of the device main body 2, and conveys the sheet S supported on the sheet tray 10 to the image forming unit 5 by the sheet conveying unit 30. The sheet tray 10 is located at the bottom end of the device main body 2. The image forming unit 5 is located above the sheet tray 10.

[0030] The sheet tray 10 supports the sheets S to be fed toward the image forming unit 5. The sheet 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 out forward from the storage position.

[0031] 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 apparatus main body 2, a conveying path P1 for the sheet S is configured, which runs from the sheet tray 10 to the sheet discharge tray 22 via the image forming section 5.

[0032] The sheets S supported on the sheet 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 sheet 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 sheet tray 10 one by one.

[0033] The sheet S sent to the conveying path P1 is conveyed toward the image forming unit 5 by the conveying roller pair 34, the registration roller 35a, and the driven roller 35b.

[0034] The registration rollers 35a regulate the movement of the leading edge of the sheet S being transported from the sheet tray 10 toward the image forming unit 5, stop the sheet S temporarily, correct the skew of the sheet S, and then transport the sheet S toward the image forming unit 5 at a predetermined timing. The registration rollers 35a are rollers for correcting the skew of the sheet S being fed from the sheet tray 10 toward the image forming unit 5.

[0035] The image forming unit 5 is disposed above the paper feed 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 corresponding to the colors yellow, magenta, cyan, and black. In other words, the image forming unit 5 has multiple photosensitive drums 51 corresponding to images of multiple colors.

[0036] 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.

[0037] The drawer 59 is detachably supported on the device body 2. The drawer 59 is configured to be movable in the front-rear direction, and can be attached to and detached from the device body 2 through the front opening 2F of the device body 2 by opening the front cover 21.

[0038] 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.

[0039] When the front cover 21 is in the open position, the drawer 59 attached to the device main body 2 can be pulled out and removed from the device main body 2 by moving it forward through the front opening 2F.

[0040] 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.

[0041] Of the four photosensitive drums 51 provided in the image forming unit 5, the photosensitive drum 51 corresponding to yellow is the first photosensitive drum 51Y, which is arranged most upstream in the sheet transport direction, the photosensitive drum 51 corresponding to magenta is the second photosensitive drum 51M, which is arranged downstream in the sheet transport direction from the second photosensitive drum 51M, the photosensitive drum 51 corresponding to cyan is the third photosensitive drum 51C, which is arranged downstream in the sheet transport direction from the third photosensitive drum 51C, and the photosensitive drum 51 corresponding to black is the fourth photosensitive drum 51K.

[0042] The apparatus main body 2 has an exposure unit 56 that exposes the surfaces of the photosensitive drums 51. The exposure unit 56 includes a laser diode, a polarizer, a lens, a mirror, etc. The exposure unit 56 is configured to irradiate each photosensitive drum 51 with laser light to expose the surface of each photosensitive drum 51. The exposure unit 56 is fixed to the upper part of the apparatus main body 2.

[0043] The exposure unit 56 includes a first scanning section 561Y that scans a light beam onto the surface of the first photosensitive drum 51Y, a second scanning section 561M that scans a light beam onto the surface of the second photosensitive drum 51M, a third scanning section 561C that scans a light beam onto the surface of the third photosensitive drum 51C, and a fourth scanning section 561K that scans a light beam onto the surface of the fourth photosensitive drum 51K.

[0044] 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.

[0045] 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 the exposure unit 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.

[0046] 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.

[0047] 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 sheet tray 10 to form an image.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The sheet S on which the toner image has been thermally fixed is transported from the fixing device 60 to the downstream side in the sheet transport direction.

[0052] An intermediate paper discharge roller 68a and a driven roller 68b arranged opposite the intermediate paper discharge roller 68a are disposed downstream in the sheet conveying direction of the fixing device 60. A paper discharge roller 69a and a driven roller 69b arranged opposite the paper discharge roller 69a are disposed downstream in the sheet conveying direction of the intermediate paper discharge roller 68a and the driven roller 68b.

[0053] The sheet transported downstream of the fixing device 60 in the sheet transport direction is transported by intermediate discharge rollers 68a and driven rollers 68b, and further transported by discharge rollers 69a and driven rollers 69b, and discharged onto the discharge tray 22.

[0054] 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.

[0055] The image forming apparatus 1 includes a power supply board 11 on which a power supply circuit is formed, and a board case 12 for accommodating the power supply board 11. The power supply board 11 is an example of a circuit board, and the board case 12 is an example of a case. The board case 12 is formed of a conductive sheet metal member and is grounded. The board case 12 is disposed between the sheet tray 10 and the belt device 40 and the fixing device 60 in the vertical direction.

[0056] The board case 12 has a case body 121 and a lid portion 122. The lid portion 122 is located below the case body 121. The case body 121 covers the power supply board 11 from above, and the lid portion 122 covers the power supply board 11 from below.

[0057] 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.

[0058] The image forming apparatus 1 has a re-conveyance path P2 that guides the sheet S, which has been conveyed along the conveyance path P1 and passed through the fixing device 60, to the conveyance path P1 that is upstream of the registration rollers 35a in the sheet conveyance direction. The re-conveyance path P2 is a path for re-conveying the sheet S to the image forming unit 5, for example, in order to form an image on the other side of the sheet S, one side of which has an image formed in the image forming unit 5. The direction in which the sheet S is conveyed along the re-conveyance path P2 is the re-conveyance direction.

[0059] The re-conveying path P2 branches off from the conveying path P1 at a branching point Pb located between the fixing device 60 and the intermediate paper discharge roller 68a, then extends forward between the substrate case 12 and the sheet 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.

[0060] The sheet S transported from the fixing device 60 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.

[0061] 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.

[0062] The image forming apparatus 1 includes a lower chute 71 and an upper chute 72 that form a re-conveyance path P2. The lower chute 71 is located between the sheet tray 10 and the substrate case 12 in the vertical direction. The lower chute 71 is disposed below the re-conveyance path P2 that is formed between the sheet tray 10 and the substrate case 12.

[0063] The lower chute 71 guides the sheet S from below. The lower chute 71 is supported on the device main body 2 so as to be movable in the front-to-rear direction. The lower chute 71 attached to the device main body 2 can be removed from the device main body 2 by pulling it out rearward.

[0064] The upper chute 72 is located above the lower chute 71 and in front of the substrate case 12. The front of the substrate case 12 is an example of the downstream side in the re-conveyance direction of the case. The upper chute 72 is located above the re-conveyance path P2 formed between the sheet tray 10 and the substrate case 12. The upper chute 72 guides the sheet S together with the lower chute 71. The upper chute 72 guides the sheet S from above.

[0065] In the image forming apparatus 1, the re-conveying section 7 is made up of the lower chute 71, the upper chute 72, the re-conveying path P2, the first re-conveying roller pair 36, and the second re-conveying roller pair 37. The re-conveying section 7 is located between the image forming section 5 and the sheet tray 10, and re-conveys the sheet S along the re-conveying direction to the image forming section 5 in order to form an image on the other side of the sheet S, one side of which has an image formed in the image forming section 5.

[0066] The power supply board 11 and the board case 12 are located between the image forming unit 5 and the lower chute 71 that constitutes the re-conveying unit 7. The board case 12 is fixed to the device main body 2 in an orientation in which the lid part 122 is located closer to the re-conveying unit 7 than the case main body 121.

[0067] 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.

[0068] [Main frame] As shown in Figures 2 to 4, the device body 2 includes a first body frame 24 and a second body frame 25 that are spaced apart in the left-right direction. The first body frame 24 is located at the right end of the device body 2, and the second body frame 25 is located at the left end of the device body 2. The first body frame 24 extends in the front-rear and up-down directions and is disposed with its plate surface facing left-right. The second body frame 25 extends in the front-rear and up-down directions and is disposed with its plate surface facing left-right.

[0069] The power supply board 11, the board case 12, and the upper chute 72 are arranged between the first body frame 24 and the second body frame 25. The power supply board 11 and the board case 12 are supported by the first body frame 24 and the second body frame 25.

[0070] The first body frame 24 has a case support portion 241, and the second body frame 25 has a case support portion 251. The case support portion 241 of the first body frame 24 supports the right end portion of the board case 12, and the case support portion 251 of the second body frame 25 supports the left end portion of the board case 12.

[0071] The upper chute 72 is rotatably supported by the first body frame 24 and the second body frame 25. The front end of the upper chute 72 is rotatably supported by the first body frame 24 and the second body frame 25, and the rear end is fixed to the board case 12.

[0072] [Up Shoot] 1 and 3 to 5, the upper chute 72 has a chute main body 721, a rotation shaft 722, and a fixed portion 723. The chute main body 721 is formed of a plate-shaped member and has a guide surface 72A facing the re-conveying path P2. The guide surface 72A is formed with a guide rib 721a that is formed along the re-conveying direction and protrudes toward the re-conveying path P2.

[0073] The pivot shaft 722 protrudes in the left-right direction from the front end of the chute main body 721. The pivot shaft 722 has a right pivot shaft 722R that protrudes rightward from the right end of the front end of the chute main body 721, and a left pivot shaft 722L that protrudes leftward from the left end of the front end of the chute main body 721. The axial direction of the pivot shaft 722 is the left-right direction.

[0074] The first main body frame 24 of the device main body 2 has a bearing hole 242 that rotatably supports the right rotating shaft 722R. The second main body frame 25 of the device main body 2 has a bearing hole 252 that rotatably supports the left rotating shaft 722L. The right rotating shaft 722R and the left rotating shaft 722L are rotatably supported in the bearing holes 242, 252, so that the upper chute 72 is rotatably supported on the device main body 2.

[0075] The upper chute 72 is rotatable between a first position (position shown in FIG. 6) in which the guide surface 72A is located above the re-conveyance path P2 and forms the re-conveyance path P2 together with the lower chute 71, and a second position (position shown in FIG. 7) in which the upper chute 72 is rotated toward the lower chute 71 around a rotation shaft 722 relative to the first position. When the upper chute 72 is rotated to the second position, the upper chute 72 does not form the re-conveyance path P2.

[0076] When the upper chute 72 is in the first position, the rotation shaft 722 is located at the front end portion, which is the downstream end portion in the re-conveyance direction of the upper chute 72.

[0077] The fixing portions 723 are portions for fixing the upper chute 72 to the device body 2. The fixing portions 723 protrude rearward from the rear end portion of the chute body 721. The fixing portions 723 are formed at the left and right end portions of the upper chute 72.

[0078] The fixing portion 723 has a fixing hole 723a formed therein, through which a fixing tool can be inserted to fix the upper chute 72 to the device body 2. The fixing hole 723a passes through the fixing portion 723 in the up-down direction when the upper chute 72 is in the first position.

[0079] [Support structure of the rotating shaft using bearing holes] (Right rotation shaft and bearing hole of first main body frame) As shown in FIG. 8(a), the bearing hole 242 of the first main body frame 24, which rotatably supports the right rotation shaft 722R, is formed in a circular shape and has a fitting opening 242a that opens to a part of the circumferential direction.

[0080] In this embodiment, the fitting opening 242a is located at the lower end of the bearing hole 242. In other words, the bearing hole 242 is opened downward by the fitting opening 242a. The axial direction of the bearing hole 242 is the left-right direction and coincides with the axial direction of the rotation shaft 722.

[0081] The dimension of the fitting opening 242a in the bearing hole 242 is WR in an orthogonal direction perpendicular to the axial direction of the rotating shaft 722. The orthogonal direction perpendicular to the axial direction of the rotating shaft 722 is a direction along the circumferential direction of the fitting opening 242a. In this embodiment, the orthogonal direction perpendicular to the axial direction of the rotating shaft 722 is the front-rear direction.

[0082] Furthermore, the direction along the straight line SL connecting the center Wc of the fitting opening 242a in the orthogonal direction to the center Bc of the bearing hole 242, and the direction from the center Wc to the center Bc, is the direction from the fitting opening 242a to the bearing hole 242. In this embodiment, the direction along the straight line SL is the up-down direction, and the direction from the fitting opening 242a to the bearing hole 242 is the upward direction.

[0083] 8(b), the right-hand rotation shaft 722R is formed into a two-chamfered shape by chamfering the outer peripheral surface of a cylindrical shape at two parallel sides. The right-hand rotation shaft 722R has a first length L1R, which is the length in a first direction perpendicular to the axial direction of the rotation shaft 722, and a second length L2R, which is the length in a second direction perpendicular to the axial direction and the first direction of the rotation shaft 722. The second length L2R is shorter than the first length L1R.

[0084] In this embodiment, the first direction when the upper chute 72 is in the first position is the front-to-rear direction, and the second direction when the upper chute 72 is in the first position is the up-to-down direction. Also, the first direction when the upper chute 72 is in the second position is the up-to-down direction, and the second direction when the upper chute 72 is in the second position is the front-to-rear direction.

[0085] The dimension WR of the fitting opening 242a in the bearing hole 242 in the orthogonal direction is greater than the second length L2R of the right rotation shaft 722R and smaller than the first length L1R of the right rotation shaft 722R.

[0086] The right-hand rotation shaft 722R is formed on the upper chute 72 in such a position that when the upper chute 72 is in the second position, the first direction coincides with the direction from the insertion opening 242a toward the bearing hole 242, and when the upper chute 72 is in the first position, the first direction intersects with the direction from the insertion opening 242a toward the bearing hole 242.

[0087] Therefore, as shown in Figure 9, when the upper chute 72 is in the second position and the right-hand rotating shaft 722R has come out of the bearing hole 242, the right-hand rotating shaft 722R can be inserted into the bearing hole 242 through the insertion opening 242a by moving the right-hand rotating shaft 722R from below the bearing hole 242 toward the bearing hole 242.

[0088] That is, when the upper chute 72 is in the second position, the second direction of the right rotating shaft 722R coincides with the direction perpendicular to the fitting opening 242a of the bearing hole 242. Furthermore, the second length L2R of the right rotating shaft 722R in the second direction is smaller than the dimension WR of the fitting opening 242a in the perpendicular direction. Therefore, by moving the right rotating shaft 722R in the direction from the fitting opening 242a toward the bearing hole 242, it is possible to insert the right rotating shaft 722R into the bearing hole 242 through the fitting opening 242a (see FIG. 10).

[0089] When the upper chute 72 is rotated and moved to the first position from the state shown in Figure 10 in which the upper chute 72 is in the second position and the right rotating shaft 722R is inserted into the bearing hole 242, the first direction of the right rotating shaft 722R and the direction from the insertion opening 242a toward the bearing hole 242 intersect, as shown in Figure 11.

[0090] In this embodiment, when the upper chute 72 is in the first position, the first direction of the right rotating shaft 722R is perpendicular to the direction from the fitting opening 242a toward the bearing hole 242. In addition, the first direction of the right rotating shaft 722R is coincident with the perpendicular direction of the fitting opening 242a in the bearing hole 242.

[0091] 11, the first length L1R of the right rotating shaft 722R is larger than the dimension WR of the fitting opening 242a in the orthogonal direction, and therefore the right rotating shaft 722R is prevented from slipping out of the bearing hole 242 through the fitting opening 242a. Therefore, the right rotating shaft 722R of the upper chute 72 can be stably maintained in a state in which it is supported by the bearing hole 242 of the first main body frame 24.

[0092] (Left rotation shaft and bearing hole of second main frame) As shown in FIG. 12, the bearing hole 252 of the second main body frame 25 that rotatably supports the left rotation shaft 722L is formed in a circular shape and has a fitting opening 252a that opens to a part of the circumferential direction.

[0093] In this embodiment, the fitting opening 252a is located at the lower end of the bearing hole 252, and the bearing hole 252 is opened downward by the fitting opening 252a. The axial direction of the bearing hole 252 is the left-right direction and coincides with the axial direction of the rotation shaft 722.

[0094] The dimension of the fitting opening 252a in the bearing hole 252 is WL in a direction perpendicular to the axial direction of the rotating shaft 722. The direction perpendicular to the axial direction of the rotating shaft 722 is a direction along the circumferential direction of the fitting opening 252a.

[0095] The direction from the fitting opening 252a toward the bearing hole 252 is, as in the case of the bearing hole 242, a direction along a straight line connecting the center of the fitting opening 252a in the orthogonal direction and the center of the bearing hole 252, and is a direction from the center of the fitting opening 252a toward the center of the bearing hole 252. In this embodiment, the direction from the fitting opening 252a toward the bearing hole 252 is an upward direction.

[0096] The left rotating shaft 722L has a cylindrical outer circumferential surface that is chamfered along two parallel sides to form a two-chamfered shape. The left rotating shaft 722L has a first length L1L in the first direction and a second length L2L in the second direction. The second length L2L is shorter than the first length L1L.

[0097] The dimension WL of the fitting opening 252a in the bearing hole 252 in the orthogonal direction is greater than the second length L2L of the left rotation shaft 722L and smaller than the first length L1L of the left rotation shaft 722L.

[0098] The first length L1L and the second length L2L of the left rotating shaft 722L are respectively smaller than the first length L1R and the second length L2R of the right rotating shaft 722R. Also, the dimension WL of the fitting opening 252a in the bearing hole 252 is smaller than the dimension WR of the fitting opening 252a in the bearing hole 242.

[0099] In other words, the left rotating shaft 722L and the right rotating shaft 722R are formed to have different sizes, and the fitting opening 242a and the fitting opening 252a are formed to have different sizes. Therefore, for example, the right rotating shaft 722R cannot be inserted into the bearing hole 252 through the fitting opening 252a, which makes it possible to prevent the upper chute 72 from being attached to the device body 2 in the left-right reversed state.

[0100] The left rotating shaft 722L and bearing hole 252 are different in size from the right rotating shaft 722R and bearing hole 242, respectively, but in other respects the left rotating shaft 722L and bearing hole 252 and the right rotating shaft 722R and bearing hole 242 are configured in the same way.

[0101] In this way, in the image forming apparatus 1, the rotating shafts 722 (right rotating shaft 722R and left rotating shaft 722L) are configured to be insertable into the bearing holes 242, 252 through the fitting openings 242a, 252a. Therefore, when attaching the upper chute 72 to the apparatus main body 2, by inserting the rotating shafts 722 into the bearing holes 242, 252 through the fitting openings 242a, 252a, the rotating shafts 722 can be easily supported by the bearing holes 242, 252.

[0102] In the image forming apparatus 1, the dimensions WR and WL of the insertion openings 242a and 252a in the orthogonal direction are greater than the second lengths L2R and L2L of the rotation shaft 722 and smaller than the first lengths L1R and L1L.

[0103] Therefore, after inserting the rotating shaft 722 into the bearing holes 242, 252 with the first direction of the rotating shaft 722 aligned with the direction from the insertion openings 242a, 252a toward the bearing holes 242, 252, the upper chute 72 is rotated to a position where the first direction of the rotating shaft 722 intersects with the direction from the insertion openings 242a, 252a toward the bearing holes 242, 252, thereby making it possible to prevent the rotating shaft 722 from coming out of the bearing holes 242, 252.

[0104] Furthermore, in the image forming apparatus 1, when the upper chute 72 is in the second position, the first direction coincides with the direction from the insertion openings 242a, 252a toward the bearing holes 242, 252, and when the upper chute 72 is in the first position, the first direction intersects with the direction from the insertion openings 242a, 252a toward the bearing holes 242, 252.

[0105] This allows the rotating shaft 722 to be inserted into and removed from the bearing holes 242, 252 through the fitting openings 242a, 252a when the upper chute 72 is rotated to the second position where the re-conveying path P2 is not formed. Also, when the upper chute 72 is rotated to the first position where the re-conveying path P2 is formed, the rotating shaft 722 inserted into the bearing holes 242, 252 can be prevented from coming out of the bearing holes 242, 252.

[0106] [Circuit board case] (Case body) As shown in FIGS. 1 and 13, the case body 121 of the substrate case 12 has an upper plate 1211, a front plate 1212, and a rear plate 1213.

[0107] The upper plate 1211 is located above the power supply board 11. The upper plate 1211 extends in the front-rear and left-right directions, and is disposed with its plate surface facing up and down. The front plate 1212 extends downward from the front end of the upper plate 1211. The rear plate 1213 extends downward from the rear end of the upper plate 1211.

[0108] The front plate 1212 has a fixing flange 1214. The fixing flange 1214 protrudes forward from the lower end of the front plate 1212. The fixing flanges 1214 are provided on the left and right ends of the front plate 1212. The fixing flanges 1214 are formed with a case screw hole 1214a and a chute screw hole 1214b. The case screw hole 1214a and the chute screw hole 1214b each penetrate in the up-down direction.

[0109] The case screw hole 1214a can be threaded with a screw 91 (see FIG. 3) for fixing the lid portion 122 to the case body 121. The chute screw hole 1214b can be threaded with a screw 92 (see FIG. 3) for fixing the upper chute 72 to the case body 121. The screw 92 is an example of a fixing device for fixing the upper chute to the device body.

[0110] The rear plate 1213 has a fixing flange 1215. The fixing flange 1215 protrudes rearward from the lower end of the rear plate 1213. The fixing flange 1215 is provided on the left and right ends of the rear plate 1213. The fixing flange 1215 is formed with a case screw hole 1215a. The case screw hole 1215a penetrates in the up-down direction. A screw 91 (see FIG. 3) for fixing the lid portion 122 to the case main body 121 can be screwed into the case screw hole 1215a.

[0111] (Lid) As shown in FIGS. 1 and 14, the cover portion 122 of the substrate case 12 has a lower plate 1221, a front plate 1222, and a rear plate 1223.

[0112] The lower plate 1221 is located below the power supply board 11. The lower plate 1221 extends in the front-rear and left-right directions, and is disposed with its plate surface facing up and down. The front plate 1222 extends upward from the front end of the lower plate 1221. The rear plate 1223 extends upward from the rear end of the lower plate 1221.

[0113] The lower plate 1221 has formed therein board holes 1221a for fixing the power supply board 11 to the board case 12 and the device main body 2. The board holes 1221a penetrate in the vertical direction and are arranged at the four corners of the lower plate 1221. An earth screw hole 1221b for grounding the board case 12 is formed at the front right corner of the lower plate 1221.

[0114] The board hole 1221a can receive a screw 93 (see FIG. 3) for fixing the power supply board 11 to the board case 12 and the device body 2. The earth screw hole 1221b can receive a screw 94 (see FIG. 3) for grounding the board case 12.

[0115] The front plate 1222 has a fixing flange 1224. The fixing flange 1224 protrudes forward from the lower end of the front plate 1222. The fixing flange 1224 is provided on the left and right ends of the front plate 1222. The fixing flange 1224 has a case hole 1224a formed therein. The case hole 1224a penetrates in the up-down direction.

[0116] The case holes 1224a can receive screws 91 (see FIG. 3) for fixing the lid portion 122 to the case body 121. The front plate 1222 has a flange 1226 that protrudes forward from the lower end of the front plate 1222 between the left and right fixing flanges 1224.

[0117] The rear plate 1223 has a fixing flange 1225. The fixing flange 1225 protrudes rearward from the lower end of the rear plate 1223. The fixing flange 1225 is provided on the left and right ends of the rear plate 1223. The fixing flange 1225 is formed with a case hole 1225a. The case hole 1225a penetrates in the up-down direction. A screw 91 (see FIG. 3) for fixing the lid portion 122 to the case main body 121 can be inserted into the case hole 1225a.

[0118] (Fixing the circuit board case) As shown in Figures 3, 7, 13, and 14, in the substrate case 12, the lid portion 122 is fixed to the case body 121 by inserting screws 91 into the case holes 1224a and 1225a of the lid portion 122 and then threading them into the case screw holes 1214a and 1215a of the case body 121.

[0119] 3, 4, 14, and 15, fixing holes 11a are formed in the four corners of the power supply board 11. By inserting screws 93 into the board holes 1221a of the lid portion 122 and the fixing holes 11a of the power supply board 11, and then fastening the inserted screws 93 to the case support portions 241 of the first main body frame 24 and the case support portions 251 of the second main body frame 25, the power supply board 11 can be fixed to the device main body 2.

[0120] 3, 4, and 14, the device main body 2 is provided with a grounded earth wire 27. The earth wire 27 extends from the first main body frame 24 toward the power supply board 11. The earth wire 27 has, at its tip, a fixing portion 27a formed with a hole through which a screw 94 can be inserted. With the screw 94 inserted into the fixing portion 27a of the earth wire 27, the screw 94 can be threaded into the earth screw hole 1221b of the lid portion 122, thereby fastening the earth wire 27 to the lid portion 122 and grounding the board case 12.

[0121] As shown in Figures 3 to 5, 13, and 15, when the upper chute 72 is in the first position, the upper chute 72 can be fixed to the board case 12 by inserting a screw 92 into the fixing hole 723a of the upper chute 72 and tightening the inserted screw 92 into the chute screw hole 1214b of the case body 121.

[0122] In this case, the board case 12 is supported by the first body frame 24 and the second body frame 25 of the device body 2, and the upper chute 72 is fixed to the device body 2 via the board case 12. In other words, the screw 92 fixes the rear end portion of the upper chute 72, which is the upstream end portion in the re-conveyance direction, to the device body 2.

[0123] 3 and 6, when the upper chute 72 is in the first position, the rear end of the chute body 721 of the upper chute 72 covers from below the flange 1226 of the lid portion 122 of the substrate case 12. This prevents the lid portion 122 from moving downward by the upper chute 72.

[0124] [Replacing the power supply board] In the image forming apparatus 1, when repairing or replacing the power supply board 11, it can be done as follows.

[0125] First, the sheet tray 10 and the lower chute 71 are removed from the device main body 2, and as shown in Figures 2 and 3, the upper chute 72 and the lid portion 122 of the substrate case 12 are exposed from the inside to the outside of the device main body 2. In this case, the device main body 2 can be placed with the bottom surface facing upward.

[0126] In this state, when the screw 92 is removed from the upper chute 72 and the board case 12, the rear end of the upper chute 72 is released from the device main body 2, and the upper chute 72 becomes rotatable from the first position to the second position about the rotation shaft 722. After rotating the upper chute 72 from the first position shown in Fig. 6 to the second position shown in Fig. 7, the screws 91 and 93 are removed from the board case 12 and the power supply board 11, and the lid portion 122 can be removed from the case main body 121.

[0127] In this case, since the upper chute 72 has rotated to the second position, the rear end of the upper chute 72 is not covered by the flange portion 1226 of the lid portion 122, and the lid portion 122 can be moved toward the bottom side of the device main body 2.

[0128] 4, when the cover 122 is removed from the case body 121, the power supply board 11 can be widely exposed on the bottom side of the device body 2. When the cover 122 is removed, the screws 93 that fastened the power supply board 11 to the device body 2 are removed, so the power supply board 11 can be removed from the device body 2 for repair or replacement.

[0129] In this way, with the upper chute 72 and the lid portion 122 of the board case 12 exposed from the device body 2, the upper chute 72 is rotated from the first position to the second position and the lid portion 122 is removed, thereby making it possible to repair or replace the power supply board 11. This reduces the effort required to repair or replace the power supply board 11, and makes it possible to easily repair or replace the power supply board 11.

[0130] Furthermore, in the image forming apparatus 1, the exposure unit 56 is fixed to the top of the apparatus main body 2, so it is not possible to open the top of the apparatus main body 2 to replace the power supply board 11. However, because the power supply board 11 can be exposed on the bottom side of the apparatus main body 2, the effort required for repairing and replacing the power supply board 11 is reduced, and the power supply board 11 can be easily repaired and replaced.

[0131] Furthermore, in the image forming apparatus 1, the image forming unit 5 has multiple photosensitive drums 51 corresponding to images of multiple colors, so if the top of the apparatus main body 2 were opened to replace the power supply board 11, it would be necessary to remove the multiple photosensitive drums 51 from the apparatus main body, which would be cumbersome. On the other hand, in the image forming apparatus 1, the power supply board 11 can be exposed on the bottom side of the apparatus main body 2, so the effort required for repairing and replacing the power supply board 11 is reduced, and the power supply board 11 can be easily repaired and replaced. [Explanation of symbols]

[0132] 1. Image forming device 2. Device body 5 Image forming unit 7 Re-feed section 10 sheet trays 11 Power supply board 12 Circuit board case 24 First body frame 25 Second body frame 51 Photosensitive drum 56 Exposure unit 71 Down Shot 72 Up Shot 92 screws 121 Case body 122 Lid 242, 252 bearing hole 242a, 252a inlet 722 Rotating shaft 722L left rotation axis 722R Right rotating shaft L1L, L1R (rotation axis) first length L2L, L2R (rotation axis) second length P2 Re-transportation route S seat WL, WR (perpendicular to the insertion opening) dimensions

Claims

1. A device body, a sheet tray located at the bottom end of the device body; an image forming unit located above the sheet tray and forming an image on a sheet; a re-conveying unit located between the image forming unit and the sheet tray, for re-conveying the sheet along a re-conveying direction to the image forming unit in order to form an image on the other side of the sheet having an image formed on one side by the image forming unit; a circuit board located between the image forming unit and the re-feeding unit; a case having a case body and a lid portion for accommodating the circuit board, the lid portion being fixed to the device body in a position where it is located closer to the re-transport unit than the case body; Equipped with The re-transport unit a lower chute positioned between the sheet tray and the case for guiding sheets; an upper chute located downstream of the case in the re-conveying direction and guiding the sheet together with the lower chute; a fixing device for fixing the upper chute to the device body, The upper chute is the conveying member is rotatable between a first position where the conveying member forms a sheet re-transport path together with the lower chute and a second position where the conveying member is rotated toward the lower chute about a rotation axis relative to the first position, the rotation shaft is located at a downstream end of the upper chute in the re-conveyance direction, The fixing device fixes an upstream end of the upper chute in the re-conveying direction to the main body of the image forming apparatus.

2. the image forming unit includes a photosensitive drum and an exposure unit that irradiates the photosensitive drum with laser light; 2. The image forming apparatus according to claim 1, wherein the exposure unit is fixed to an upper portion of the apparatus body.

3. 2. The image forming apparatus according to claim 1, wherein the image forming section has a plurality of photosensitive drums corresponding to images of a plurality of colors.

4. the device body has a bearing hole that rotatably supports the rotation shaft of the upper chute, The bearing hole is opened by a fitting opening that opens in a part of the circumferential direction, The image forming apparatus according to claim 1 , wherein the rotation shaft is insertable into the bearing hole through the insertion opening.

5. the rotation shaft has a first length in a first direction perpendicular to an axial direction of the rotation shaft, and a second length in a second direction perpendicular to the axial direction and the first direction, the second length being shorter than the first length; The image forming apparatus according to claim 4 , wherein a dimension of the insertion opening in a direction perpendicular to the axial direction is greater than the second length and smaller than the first length.

6. When the upper chute is in the second position, the first direction coincides with a direction from the insertion opening toward the bearing hole, 6. The image forming apparatus according to claim 5, wherein when the upper chute is in the first position, the first direction intersects with a direction from the insertion opening toward the bearing hole.

Images