JP2018180398A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can appropriately prevent the occurrence of sheet conveyance failure, and can be manufactured advantageously in terms of manufacturing efficiency.SOLUTION: An image forming apparatus comprises: a fixing part 19 that is arranged on a sheet conveyance path 26 and conveys a sheet S in a first direction; an ejection conveyance unit 16 that ejects the S sheet to which a toner image is fixed by the fixing part 19 to the outside; and a guide unit 7 that is provided between the fixing part 19 and ejection conveyance unit 16 and guides the movement of the sheet S toward the ejection conveyance unit 16. The fixing part 19 has contact parts 45 that are removably attached to the ejection conveyance unit 16, and regulate the attachment position of the guide unit 7 with respect to the ejection conveyance unit 16 to regulate the width of a conveyance path in a bent part 26D.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus.

  In an image forming apparatus such as a printer, a toner image corresponding to image data is formed on a sheet by an image forming unit. The toner image formed on the sheet is fixed to the sheet by applying heat and pressure by the fixing device. The sheet on which the toner image is fixed is discharged to the outside by the discharge device. In the case of double-sided printing of an image on a sheet, when fixing of the toner image on one side of the sheet is completed, the sheet on which the toner image is fixed on one side is re-conveyed to the image forming unit.

  By the way, when the toner image is fixed on one side of the sheet, the sheet may be curled due to heat, pressure or the like at the time of fixing of the toner image. Therefore, in an image forming apparatus capable of forming an image on both sides of a sheet, sheet conveyance failure is likely to occur at a bent portion of the sheet conveyance path. Therefore, in order to prevent the occurrence of conveyance failure of the sheet at the bent portion or the like due to curling, the discharge device applies a stiffness to the sheet before reconveying the sheet to the image forming unit. (See, for example, Patent Document 1).

JP, 2006-62855, A

  However, depending on the destination of the image forming apparatus, the sheet characteristics such as the stiffness of the sheet may differ, so that it may not be possible to appropriately prevent the transport failure occurring in the bent portion. Therefore, it is necessary to adjust the transport route appropriately in the manufacturing process of the image forming apparatus according to the strength of the sheet used at the destination. For example, in an image forming apparatus manufacturing process, for an image forming apparatus for a destination using a strong sheet, the gap at the bending portion is set narrow, while an image forming for a destination using a sheet having a low waist For the device, it is necessary to set a wide gap in the bent portion. As described above, it is disadvantageous in terms of manufacturing efficiency to adjust the gap of the bent portion for each destination.

  An object of the present invention is to provide an image forming apparatus which can appropriately prevent occurrence of sheet conveyance failure and can be manufactured efficiently and efficiently.

  An image forming apparatus according to one aspect of the present invention includes an image forming unit, a sheet conveyance path, a first unit, a second unit, and a guide unit. The image forming unit forms a toner image on a sheet. The sheet is transported by the sheet transport path and has a bending portion. The first unit is disposed on the sheet conveyance path, and conveys the sheet in a first predetermined direction. The second unit is disposed downstream of the first unit in the sheet conveyance direction, and conveys the sheet in a second direction intersecting the first direction. The guide unit is provided between the first unit and the second unit, and guides movement of the sheet toward the second unit. Further, the second unit has a support portion for slidably supporting the guide unit. The first unit is detachably attached to the second unit, and an abutment portion which defines the transport path width of the bent portion by defining the attachment position of the guide unit to the second unit. Have.

  According to the present invention, it is possible to provide an image forming apparatus which can appropriately prevent the occurrence of sheet conveyance failure and can be manufactured efficiently.

FIG. 1 is a diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing the fixing unit and the discharge conveyance unit of the image forming apparatus shown in FIG. FIG. 3 is a perspective view showing the fixing unit. FIGS. 4A and 4B are diagrams showing the relationship between the movable member of the discharge conveyance unit and the fixing unit. FIG. 5 is a perspective view showing the discharge conveyance unit. FIG. 6 is a perspective view showing the movable member. FIG. 7 is a perspective view showing the main part in a state where the movable member is attached to the support frame. FIG. 8 is a perspective view of the movable member as viewed from the back side. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. FIG. 10 is an enlarged view of the main part of FIG.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. For convenience of description, the vertical direction D1, the horizontal direction D2, and the front-rear direction D3 are defined based on the state shown in FIG. 1 where the image forming apparatus is installed on a horizontal surface. The embodiments described below are merely examples embodying the present invention, and do not limit the technical scope of the present invention.

  First, the configuration of the image forming apparatus 10 will be described with reference to FIG.

  As shown in FIG. 1, the image forming apparatus 10 is a multifunction peripheral provided with various functions such as a printer, a copier, a fax machine, and a scanner. The image forming apparatus 10 includes an image reading unit 12, an image forming unit 14, and a discharge conveyance unit 16 (an example of a second unit of the present invention), and forms an image on a sheet S using toner based on image data. . The present invention is applicable not only to a multifunction peripheral but also to an image forming apparatus such as a printer, a copier, and a fax machine.

  The image reading unit 12 performs a process of reading an image of a document, and is provided on the upper portion of the image forming apparatus 10. The image reading unit 12 includes a document placement table 23 and an ADF (automatic document feeder) 13. When the image forming apparatus 10 functions as a copying machine or a scanner, a document is set on the document placing table 23, and after the document cover 24 is closed, a copy start instruction or a scanner start instruction is given from the operation display panel (not shown). It is input. Thus, the reading operation by the image reading unit 12 is started, and the image data of the document is read. In the case of a copy start instruction, the read image data is sent to the image forming unit 14. The ADF 13 is provided on the document cover 24. When the document is conveyed to the reading position by the ADF 13, the image reading unit 12 reads an image of the document passing the reading position.

  The image forming unit 14 forms an image on the sheet S by electrophotography based on the image data read by the image reading unit 12 or the image data input from the outside. The image forming unit 14 is not limited to the electrophotographic type, and may be another type such as an inkjet recording type. The image forming unit 14 includes the sheet feeding devices 27 and 28, the photosensitive drum 31, the charging unit 32, the developing unit 33, the light scanning device 34, the transfer roller 35, the fixing unit 19 (an example of the first unit of the present invention) A control unit (not shown) that controls the forming unit 14 in an integrated manner is provided.

  The sheet feeding devices 27 and 28 send out the sheet S on which the image forming unit 14 forms an image. Each of the paper feeding devices 27 and 28 includes a tray-shaped paper storage unit 22 and a feeding mechanism 15. A sheet S on which an image is formed by the image forming unit 14 is stacked on the sheet storage unit 22. The feeding mechanism 15 picks up and feeds the sheets S stored in the sheet storage unit 22 one by one. The feeding mechanism 15 is provided on the upper side of the right end of the sheet storage unit 22. The feeding mechanism 15 includes a feeding roller 51 and a conveyance roller pair 52. When an instruction for feeding the sheet S to the image forming apparatus 10 is input, the feeding motor (not shown) is rotationally driven, whereby the feeding roller 51 and the feeding roller pair 52 are rotated. . Then, the sheet S is fed from the sheet storage unit 22 by the feeding roller 51, and the sheet S is transported to the downstream side in the feeding direction by the transport roller pair 52.

  Here, in the image forming apparatus 10, a first conveyance path 26 (an example of a sheet conveyance path of the present invention) and a second conveyance path 39 are formed. The first conveying path 26 is for conveying the sheet S fed from the sheet feeding devices 27 and 28 to the sheet discharge tray 21. On the other hand, the second conveyance path 39 is for re-conveying the sheet S having the toner image formed on one side by the image forming unit 14 and conveyed to the discharge conveyance unit 16 to the image forming unit 14.

  The first conveyance path 26 includes a paper feed conveyance path 26A, an intermediate conveyance path 26B, and a paper discharge conveyance path 26C.

  The sheet feeding and conveying path 26A constitutes a lower portion of the first conveying path 26, and is formed in a section from the feeding mechanism 15 of the sheet feeding device 28 to the junction T2. Here, the junction T2 is a connection portion between the first conveyance path 26 and the second conveyance path 39, and is provided between the sheet feeding device 27 and the photosensitive drum 31 in the first conveyance path 26. The sheet S fed from the sheet feeding devices 27 and 28 is conveyed toward the image forming unit 14 in the sheet feeding conveyance path 26A.

  The intermediate conveyance path 26B is formed in a section that is continuous with the sheet feeding conveyance path 26A and extends from the junction point T2 to the junction point T1. Here, the branch point T1 is a connection portion between the first conveyance path 26 and the second conveyance path 39, and is provided between the fixing unit 19 and the discharge conveyance unit 16 downstream of the fixing unit 19 in the conveyance direction. It is done. A portion corresponding to the branch point T1 in the first conveyance path 26 is formed as a bending portion 26D (see FIGS. 9 and 10). In the intermediate conveyance path 26B, the sheet S carried in from the sheet feeding conveyance path 26A passes between the photosensitive drum 31 and the transfer roller 35 and the fixing unit 19, and is directed to the bending portion 26D in the first direction. Transported to

  The sheet discharge conveyance path 26C is formed in a section that is continuous with the intermediate conveyance path 26B and extends from the branch point T1 to the sheet discharge port 37. The discharge conveyance path 26 </ b> C is provided inside the discharge conveyance unit 16. In the paper discharge conveyance path 26C, the sheet S on which a toner image is formed by a movable member 70 of the guide unit 7 described later is conveyed along a second direction intersecting the intermediate conveyance path 26B directed to the paper discharge tray 21. .

  The second conveyance path 39 is a section from the branch point T1 to the junction point T2, and is formed as a route different from the intermediate conveyance path 26B. The second conveyance path 39 extends in the up-down direction D1 so as to be generally aligned on the right side of the intermediate conveyance path 26B. The second conveyance path 39 is used to re-convey the sheet S having the image formed on one side to the image forming unit 14 when forming an image on both sides of the sheet S.

  The photosensitive drum 31 carries a toner image, and is provided in the middle of the intermediate conveyance path 26B. When the image forming operation is started, the charging unit 32 charges the surface of the photosensitive drum 31 to a uniform potential. Further, a laser beam corresponding to the image data is scanned from the light scanning device 34 to the photosensitive drum 31. As a result, an electrostatic latent image is formed on the photosensitive drum 31. Thereafter, toner is attached to the electrostatic latent image by the developing unit 33, and a toner image is formed on the photosensitive drum 31. The transfer roller 35 is disposed to face the photosensitive drum 31 with the intermediate conveyance path 26B interposed therebetween. When the sheet S passing through the intermediate conveyance path 26 B passes between the transfer roller 35 and the photosensitive drum 31, the toner image carried on the photosensitive drum 31 is transferred to the sheet S by the transfer roller 35. The sheet S on which the toner image has been transferred further moves on the intermediate conveyance path 26B, and is conveyed to the fixing unit 19 disposed downstream of the transfer roller 35 in the conveyance direction of the sheet S.

  The fixing unit 19 includes a heating roller 41 for applying heat to the toner image, and a pressure roller 42 for applying pressure to the toner image. The fixing unit 19 fixes the toner image on the sheet S by applying heat and pressure to the toner image transferred to the sheet S. Further, as shown in FIGS. 2 to 4, the fixing unit 19 is detachably disposed on the intermediate conveyance path 26B, and conveys the sheet S on which the toner image is formed in the first direction along the intermediate conveyance path 26B. Do. The fixing unit 19 is arranged side by side in the front-rear direction D3, and includes a plurality of transport guides 47 that define the second passage 391, and two contact portions 45 extending in the left-right direction D2 parallel to each other with a constant interval.

  The two contact portions 45 define the transport path width of the sheet S in the thickness direction at the bent portion 26D of the first transport path 26 by defining the mounting position of the guide unit 7 described later with respect to the discharge transport unit 16. In other words, the transport path width of the bending portion 26D can be adjusted by appropriately setting the formation position of the contact portion 45. Therefore, for example, by providing the contact portions 45 at different positions for different destinations for different destinations of the sheet S, it is possible to adjust the transport path width according to the characteristics of the sheet S at the destination. For example, according to the formation position of the contact portion 45, the transport path width of the bending portion 26D at the bending portion 26D is adjusted to be narrow in the image forming apparatus 10 for the destination using the sheet S having high stiffness. In the image forming apparatus 10 for the destination using the weak sheet S, the transport path width of the bending portion 26D can be adjusted widely. The abutting portion 45 has an abutting surface 46 that abuts on the abutted surface 77 of the movable member 70 of the guide unit 7 described later in a state in which the discharge conveyance unit 16 is assembled to the fixing unit 19. The contact surface 46 is an end surface on the left side of the contact portion 45, and stands substantially vertically along the vertical direction D1. The abutting surface 46 is directed leftward to the rotating roller 74 fixed to the movable member 70 described later by abutting on the abutted surface 77 in a state where the discharge conveyance unit 16 is assembled to the fixing unit 19. The force is applied to fix the relative position of the rotating roller 74 in the discharge conveyance unit 16. That is, the contact surface 46 fixes the relative position of the rotating roller 74 in the discharge and conveyance unit 16 according to the position. For example, as shown in FIG. 4A, when the contact surface 46 is formed relatively in the left direction, the rotary roller 74 is relatively fixed in the discharge conveyance unit 16 in the left direction. On the other hand, as shown in FIG. 4B, when the contact surface 46 is formed relatively to the right side, the rotary roller 74 is relatively fixed to the right side in the discharge conveyance unit 16.

  As shown in FIG. 5, the discharge conveyance unit 16 is disposed downstream of the fixing unit 19 in the sheet conveyance direction. The discharge conveyance unit 16 conveys the sheet S in a second direction along the sheet discharge conveyance path 26C, and discharges the sheet S on which the toner image is fixed by the fixing unit 19 to the outside. The discharge conveyance unit 16 is supported by a pair of support frames 48 (an example of a support portion of the present invention) arranged to be separated in the front-rear direction D3 and integrated with the fixing portion 19. The discharge conveyance unit 16 is provided with an upstream portion of the discharge conveyance path 26 </ b> C and the reverse conveyance path 39. Hereinafter, a portion of the reverse conveyance path 39 formed in the discharge conveyance unit 16 is referred to as a “second passage 391”. Here, the sheet discharge conveyance path 26C is for discharging the sheet S on which the toner image is formed to the outside. Further, the second passage 391 is for re-conveying the sheet S having the toner image formed on one side to the image forming unit 14.

  The discharge roller pair 25 shown in FIG. 1 is provided in the vicinity of the paper discharge port 37 so as to be bi-directionally rotatable by a discharge motor (not shown). The discharge roller pair 25 is rotated in the forward direction by the discharge motor to move the sheet S along the discharge conveyance path 26C and convey the sheet S to the discharge tray 21. Specifically, the discharge roller pair 25 passes the fixing unit 19 by rotating in the forward direction when printing on both sides of the sheet S is completed when performing single-sided printing or when performing double-sided printing. The sheet S is moved along the sheet discharge conveyance path 26C, and the sheet S is discharged from the sheet discharge port 37 to the outside.

  Further, the discharge roller pair 25 conveys the sheet S toward the reverse conveyance path 39 by being rotated in the reverse direction by the discharge motor. Specifically, when printing on one side is completed when double-sided printing is performed, the sheet S that has passed the fixing unit 19 is sent to the second conveyance path 39 by rotating in the reverse direction. More specifically, the discharge roller pair 25 is stopped in a state where the leading end of the sheet S on which an image is formed on one side is exposed to the outside from the paper discharge port 37. At this time, the rear end of the sheet S is held in a state of being nipped by the discharge roller pair 25 near the sheet discharge port 37. Thereafter, the discharge roller pair 25 is reversely rotated by the reverse rotation drive of the discharge motor (not shown). As a result, the sheet S is conveyed in the reverse direction through the sheet discharge conveyance path 26C.

  The sheet S fed from the sheet discharge conveyance path 26C to the second conveyance path 39 is guided downward in the second conveyance path 39. Two transport roller pairs 43 and 44 are provided in the second transport path 39. In the second conveyance path 39, the sheet S is conveyed downward by the conveyance roller pair 43 and 44, and is again fed to the first conveyance path 26 at the junction point T2. Then, the sheet is conveyed again to the transfer roller 35 through the intermediate conveyance path 26B. The sheet S having reached the transfer roller 35 has the surface on which the image is not formed opposite to the photosensitive drum 31 again. Then, by sequentially passing through the transfer roller 35 and the fixing unit 19, an image is formed on the opposite side on which the image is not formed. Thereafter, the sheet S on which images have been formed on both sides is discharged from the sheet discharge port 37 to the sheet discharge tray 21 through the sheet discharge conveyance path 26C by the discharge roller pair 25 returned to normal rotation.

  As shown in FIG. 5, the carry-out transport unit 16 is fixed to the pair of support frames 48. The carry-out conveyance unit 16 defines a discharge conveyance path 26C and a second passage 391. The carry-out transport unit 16 has a plurality of guide claws 61 which define a second passage 391. The plurality of guide claws 61 are arranged in the left-right direction D <b> 2 above the carry-out conveyance unit 16.

  As shown in FIGS. 6 to 8, a guide unit 7 is provided between the fixing unit 19 and the carry-out conveyance unit 16. The guide unit 7 guides the movement of the sheet S toward the carry-out conveyance unit 16. The guide unit 7 includes a movable member 70, a plurality of rotary rollers 74 (an example of a load reducing member of the present invention), and a plurality of coil springs 8 (an example of a biasing member of the present invention).

  The movable member 70 is supported by a pair of support frames 48 having fitting grooves 49, and is movable relative to the carry-out transport unit 16 in the left-right direction D2. The movable member 70 has two slide parts 71 (an example of a convex part of the present invention), a plurality of rail parts 72, a plurality of fin-like parts 73, and a contact surface 77.

  One slide portion 71 is provided at each end of the movable member 70 in the front-rear direction D3. Each slide portion 71 extends in the left-right direction D2 and protrudes in the front-rear direction D3 at each of the both end portions. The two slide portions 71 are fitted in the fitting grooves 49 of the support frame 48. The fitting groove 49 extends in the left-right direction D2. Further, the fitting groove 49 has a dimension in the left-right direction D2 and the up-down direction D1 larger than that of the slide portion 71, and permits movement of the slide portion 71 in the left-right direction D2. Therefore, the slide portion 71 can move the fitting groove 49 in the left-right direction D2. Thus, the movable member 70 can be operated and moved in the left-right direction D2 with respect to the support frame 48, and can also be moved in the left-right direction D2 relative to the carry-out conveyance unit 16.

  The plurality of rail portions 72 and the plurality of fin-shaped portions 73 define a second passage 391 together with the plurality of guide claws 61 of the carry-out transfer unit 16. Then, since the movable member 70 is movable relative to the carry-out conveyance unit 16 in the left-right direction D2, the plurality of guide claws 61 of the carry-out conveyance unit 16 and the movable member are obtained by the movement of the movable member 70 in the left-right direction D2. The size of the gap between the rail portion 72 and the fin-shaped portion 73 changes. That is, by the movement of the movable member 70 in the left-right direction D2, the dimension in the thickness direction of the sheet S of the second passage 391 is expanded or reduced (see FIG. 10).

  The contact surface 77 is a portion with which the contact surface 46 of the fixing unit 19 abuts when the discharge conveyance unit 16 is assembled to the fixing unit 19. When the abutted surface 77 abuts on the abutting surface 46, the relative position of the movable member 70 in the discharging and conveying unit 16 is fixed.

  As shown in FIGS. 8 and 9, the plurality of coil springs 8 (an example of the biasing member of the present invention) are fixed to the movable member 70. In the present embodiment, the number of the plurality of coil springs 8 is three. Each coil spring 8 is fixed at one end 81 (end in the right direction) to the fixed part 75 provided at each end and center of the movable member 70 in the front-rear direction D3 and the other end 82 (left The end portion of the movable member 70 protrudes leftward from the movable member 70. The other end 82 of each coil spring 8 is fixed to or in contact with the carry-out conveyance unit 16. Therefore, the movement of each coil spring 8 in the left direction is restricted by the fixed member 6, and the coil spring 8 is contracted by moving the movable member 70 in the left direction. As a result, the movable member 70 is urged in the right direction, which is the direction in which it is separated from the carry-out transport unit 16.

  Further, the plurality of rotation rollers 74 reduce the conveyance load at the bending portion 26D of the first conveyance path 26. As shown in FIG. 6, the plurality of rotary rollers 74 are rotatably fixed to the fixed piece 76 of the movable member 70 at the portion where the fin-like portion 73 is not formed, and are arranged side by side in the front-rear direction D3. In the present embodiment, the number of the plurality of rotating rollers 74 is four.

  By the way, depending on the destination of the image forming apparatus, the characteristics of the sheet, for example, the strength of the waist and the like may differ, so that it may not be possible to appropriately prevent the transport failure occurring at the bent portion. Therefore, it is necessary to adjust the transport route appropriately in the manufacturing process of the image forming apparatus according to the strength of the sheet used at the destination. For example, in an image forming apparatus manufacturing process, for an image forming apparatus for a destination using a strong sheet, the gap at the bending portion is set narrow, while an image forming for a destination using a sheet having a low waist For the device, it is necessary to set a wide gap in the bent portion. As described above, it is disadvantageous in terms of manufacturing efficiency to adjust the gap of the bent portion for each destination.

  On the other hand, the image forming apparatus 10 of the present embodiment includes the guide unit 7 having the movable member 70 movable in the left-right direction D2, and the conveyance path width of the first conveyance path 26 at the bending portion 26D is a movable member. It is determined by the position of 70. On the other hand, the position of the movable member 70 is determined by the position of the contact surface 46 of the fixing unit 19 and the position of the abutted surface 77 of the movable member 70 in contact with the contact surface 46. Therefore, the position of the movable member 70 can be adjusted by selecting one of the formation positions of the contact surface 46 and the contact surface 77. As a result, the position at which the contact surface 46 or the contact surface 77 is formed is adjusted in advance in accordance with the characteristics of the sheet S used at the destination (for example, the waist of the sheet), whereby conveyance at the bending portion 26D It is possible to optimize the path width and prevent the occurrence of transport failure.

  By the way, the fixing unit 19 is formed to different specifications for each destination in order to cope with the difference in magnitude of the supply voltage at the destination. Therefore, if the position of the movable member 70 is selected by adjusting the position of the contact surface 46 of the fixing unit 19, bending is performed without changing the configuration of the movable member 70 including the abutted surface 77. It is possible to adjust the transport path width in the part 26D. Therefore, it is possible to unify the whole of the guide unit 7 and the discharge conveyance unit 16 into the same specification regardless of the destination, by changing the fixing unit 19 formed to different specifications for each destination. Become. As a result, the manufacturing process of the image forming apparatus 10 is simplified, which is not only advantageous for manufacturing efficiency, but also reduces the burden on inventory control.

  In the above-mentioned embodiment, although rotation roller 74 was illustrated and explained as an example of a load reduction member, the present invention is not limited to this composition. For example, the load reducing member is not limited to a rotating body such as the rotating roller 74, but may be a non-rotating body.

  Moreover, although the above-mentioned embodiment illustrated and demonstrated the coil spring as an example of a biasing member, this invention is not limited to this structure. For example, the biasing member may be a spring member other than a coil spring such as a leaf spring, or an elastic resin body such as an elastic rubber member.

  Further, in the above embodiment, the movable member 70 is provided with the slide portion 71 (convex portion), while the support groove 48 is provided in the support frame 48, whereby the moving direction of the movable member 70 is defined in the left-right direction D2. However, the present invention is not limited to this configuration. For example, by providing a through hole in the movable member 70 and providing a convex portion in the support frame 48, the moving direction of the movable member 70 may be defined in the left-right direction D2. The fitting groove of the movable member 70 is formed, for example, as extending in the left-right direction D2 and penetrating in the front-rear direction D3 in the portion where the slide portion 71 is provided. On the other hand, the convex portion of the support frame 48 is formed, for example, so as to have smaller dimensions in the left-right direction D2 and the front-rear direction D3 than the recess and project toward the movable member 70 in the front-rear direction D3.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 14 Image formation part 16 Discharge conveyance unit 19 Fixation part 26 1st conveyance path 26D bending part 45 Contact part 46 Contact surface 48 Support frame 49 Fitting groove 7 Guide unit 71 Slide part 74 Rotation roller 8 Coil spring S Sheet

Claims (7)

An image forming unit that forms a toner image on a sheet;
A sheet conveying path in which the sheet is conveyed and having a bent portion;
A first unit disposed on the sheet conveyance path for conveying the sheet in a first predetermined direction;
A second unit disposed downstream of the first unit in the sheet conveyance direction and conveying the sheet in a second direction intersecting the first direction;
A guide unit provided between the first unit and the second unit for guiding the movement of the sheet toward the second unit;
Equipped with
The second unit has a support that slidably supports the guide unit,
The first unit is detachably attached to the second unit, and an abutment that defines the transport path width at the bent portion by defining the attachment position of the guide unit to the second unit. An image forming apparatus having a section. The first unit is a fixing unit that fixes the toner image formed on the sheet by the image forming unit to the sheet,
The image forming apparatus according to claim 1, wherein the second unit is a discharge conveyance unit that discharges the sheet on which the toner image is formed by the fixing unit.   The image forming apparatus according to claim 1, wherein the guide unit has a biasing member that biases the guide unit toward the bending portion, and is in contact with the contact portion. The guide unit includes a load reducing member that reduces a transport load of the sheet passing through the bending portion,
The image forming apparatus according to claim 3, wherein the load reducing member has a protruding amount at the bending portion defined by the contact portion.   The image forming apparatus according to claim 4, wherein the load reducing member is a roller that can rotate in contact with the sheet.   The image forming apparatus according to claim 4, wherein the contact portion is formed at a position where the amount of protrusion of the load reducing member becomes large when the stiffness of the sheet passing through the bending portion is strong. One of the guide unit and the support portion has a convex portion,
The image forming apparatus according to any one of claims 1 to 6, wherein the other of the guide unit and the support portion has a fitting groove which allows movement of the convex portion.

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