JP2017132610A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which, while suppressing an increase in the number of components, can suppress generation of abnormal noise by preventing a recording medium from being stiffened by a stiffening member when the recording medium is conveyed to a reverse conveyance passage.SOLUTION: In an image forming apparatus 100, a discharge reversal roller pair 20 discharges a sheet by normal rotation, and conveys the sheet toward a reverse conveyance passage 16 by reverse rotation. A stiffening member 50 is arranged at a first position of projecting into a sheet conveyance passage 11 by friction force received from the sheet when the discharge reversal roller pair 20 normally rotates and the sheet is conveyed in a discharge direction. Further, the stiffening member 50 is arranged at a second position where the amount of projection into the sheet conveyance passage 11 is smaller compared to the first position by the friction force received from the sheet when the discharge reversal roller pair 20 reversely rotates and the sheet is conveyed in a reverse direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus provided with a plurality of waist-attaching members for imparting waist to a recording medium.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a printer or a multifunction peripheral thereof has an image forming unit that forms a toner image on a sheet (recording medium) by performing a predetermined image forming process, and heats and fixes the toner image on the sheet. A fixing unit for fixing the sheet on the upper side; and a sheet discharging unit for discharging the heat-fixed sheet to the outside.

  The paper carrying the heat-fixed toner image is easily deformed by heat and curls (has a curl) when conveyed to the paper discharge section. As a means for correcting the curl, there is provided a seating member for imparting waist to the paper when the paper is discharged by the discharge roller pair. A plurality of seating members are arranged in the paper width direction (a direction orthogonal to the paper transport direction), and deform the paper into a wave shape in a cross section perpendicular to the paper transport direction. As a result, the paper to which the waist has been given is in a state in which the curl has been corrected, so that it is neatly stacked on the paper discharge tray.

  Incidentally, an image forming apparatus that performs image forming processing on both sides of a sheet is known. As such an image forming apparatus, for example, the discharge reversing roller pair is rotated forward to cause the rear end portion of the sheet (the upstream portion in the discharging direction) to protrude outside, and then the discharge reversing roller pair is rotated reversely. 2. Description of the Related Art Image forming apparatuses that switch back a sheet and convey it to a reverse conveyance path are known.

  An image forming apparatus provided with a seating member for imparting waist to a sheet is disclosed in, for example, Patent Document 1. In the image forming apparatus disclosed in Patent Document 1, a corrugation roller (backing member) for imparting waist to a sheet, a drive unit including a solenoid or the like that moves the corrugation roller in a direction of contacting or separating the sheet, and the like are provided. ing.

JP2012-106837A

  However, in the above-described image forming apparatus that performs image forming processing on both sides of the paper, when a back-up member is provided in the paper discharge portion, the rear end portion of the paper is externally exposed by a pair of discharge reversing rollers in order to perform double-side printing on the paper. After the protrusion, when the paper is switched back and transported to the reverse transport path, the waist is imparted to the paper by the seating member. When a sheet with waist is passed through the reverse conveyance path, particularly in the curved part of the reverse conveyance path, the paper is bent in the traveling direction and the noise is generated due to the wave shape being stretched. There is.

  In addition, when providing the drive part which separates a seating member from a paper like patent document 1, there exists a problem that a number of parts increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to support a seating member when a recording medium is transported to a reverse transport path while suppressing an increase in the number of parts. It is an object of the present invention to provide an image forming apparatus capable of suppressing the generation of abnormal noise by suppressing the seating of the sheet.

  In order to achieve the above object, an image forming apparatus according to a first configuration of the present invention includes an image forming unit that transfers a toner image formed on an image carrier onto a recording medium, and the image forming unit on the recording medium. A fixing unit that melts and fixes the toner image transferred onto the recording medium, a discharge unit that discharges the recording medium on which the toner image is fixed by the fixing unit, and a conveyance unit that conveys the recording medium from the fixing unit to the discharge unit. A discharge conveyance path, and a reversal conveyance path that is provided so as to be connected to the upstream side of the discharge unit in the recording medium discharge direction, and for reversing the recording medium on which image formation has been performed on one surface and re-conveying it to the image forming unit , Provided in the discharge section so as to be able to rotate forward and reverse, and is provided in the discharge section with a pair of discharge reversing rollers for discharging the recording medium by forward rotation and transporting the recording medium to the reverse conveyance path by reverse rotation. How to thicken the recording medium in the road A plurality of lumps for imparting waist to the recording medium by deforming the recording medium into a wave shape in a cross section perpendicular to the recording medium conveyance direction. A member, and a holding unit that is provided in the discharge unit and has a guide unit that movably holds the seating member. The seating member is located at a first position protruding in the recording medium thickness direction in the discharge conveyance path by the frictional force received from the recording medium when the pair of discharge reversing rollers are rotated forward and the recording medium is conveyed in the discharge direction. When the recording medium is transported in the reverse direction by rotating the pair of discharge reversing rollers reversely, the recording medium moves in the reverse direction along the guide portion by the frictional force received from the recording medium, and discharges compared to the first position. It is arranged at the second position where the amount of protrusion into the transport path is small.

  According to the first configuration of the present invention, the seating member is moved into the discharge conveyance path by the frictional force received from the recording medium when the pair of discharge reversing rollers rotate forward and the recording medium is conveyed in the discharge direction. It is arranged at a first position protruding in the recording medium thickness direction. As a result, when the recording medium is discharged to the outside by the pair of discharge reversing rollers, the waist is given to the recording medium by the waist member.

  On the other hand, the backrest member moves in the reverse direction along the guide portion by the frictional force received from the recording medium when the discharge reverse roller pair rotates reversely and the recording medium is conveyed in the reverse direction. It is arranged at a second position where the amount of protrusion into the discharge conveyance path is smaller than the position. Accordingly, when the recording medium is transported toward the reverse transport path by the pair of discharge reversing rollers in order to perform image forming processing on both sides of the recording medium, the seating member is retracted from the first position to the second position. Therefore, it is possible to suppress the waist from being imparted to the recording medium by the seating member. For this reason, it is possible to suppress the generation of abnormal noise when the recording medium passes through the curved portion of the reverse conveyance path.

  In addition, since it is not necessary to provide a drive unit that moves the seating member in a direction in which it is in contact with or away from the recording medium, an increase in the number of components can be suppressed.

1 is a diagram illustrating an overall configuration of an in-body discharge type image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional perspective view illustrating a structure around a discharge unit of the image forming apparatus according to the embodiment of the present disclosure. FIG. 3 is a diagram illustrating a discharge unit of the image forming apparatus according to the embodiment of the present disclosure from the in-body discharge unit side. FIG. 3 is a side cross-sectional view illustrating a structure around a discharge portion of the image forming apparatus according to the embodiment of the present invention, and is a view illustrating a state in which a discharge reversing roller pair is rotating forward. FIG. 3 is a side cross-sectional view illustrating a structure around a discharge unit of the image forming apparatus according to the embodiment of the present invention, and is a diagram illustrating a state in which a discharge reversing roller pair is rotating in reverse. FIG. 3 is a perspective view illustrating a structure of a seating member of the image forming apparatus according to the embodiment of the present invention. It is the figure which showed the structure of the waisting member and guide groove of the 1st modification of this invention. It is the figure which showed the structure of the seating member and guide groove of the 2nd modification of this invention.

  Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Further, the use of the invention and the terms shown here are not limited thereto.

  FIG. 1 is a diagram illustrating an overall configuration of an in-body paper discharge type image forming apparatus according to an embodiment of the present invention. Under the image forming apparatus 100, a cassette type paper feeding unit 10 is disposed. The paper feeding unit 10 has upper and lower two-stage paper feeding cassettes 10a and 10b, and pre-printing paper (recording media) is stacked and accommodated in the paper feeding cassettes 10a and 10b. The sheets housed in the sheet feeding cassettes 10a and 10b are fed out one by one from the selected sheet feeding cassette 10a (10b) by the sheet pickup roller 10d (10e), and the fed out sheets are sent out to the sheet transport path 11. It is.

  A manual feed tray 10 c is disposed on the right side surface of the image forming apparatus 100. The manual feed tray 10c can be loaded with paper having a size different from that of the paper feed cassettes 10a and 10b. The paper placed on the manual feed tray 10 c is sent out to the paper transport path 11.

  The sheet conveyance path 11 extends in the vertical direction of the apparatus main body 2 on the left side of the sheet feeding unit 10. The sheet fed from the sheet feeding unit 10 is conveyed to the registration roller pair 12 above the sheet conveying path 11. The registration roller pair 12 sends the paper toward the image forming unit 3 in synchronization with the timing of transferring the toner image onto the paper.

  A document reading device 6 is disposed above the image forming apparatus 100, and a platen (document pressing) 24 is provided on the upper surface of the document reading device 6 so as to be openable and closable. Is attached. When copying an original, the originals placed on the original conveying device 27 are separated one by one and sent to the original reading unit, and the original reading device 6 reads the image data of the original.

  An image forming unit 3 is disposed substantially at the center of the image forming apparatus 100. The image forming unit 3 includes a photoconductor 5 that is an image carrier, and further, around the photoconductor 5 in order along its rotation direction (A direction in the drawing), a charging unit 4, an exposure unit 7, and a developing unit. A unit 8, a transfer roller 13, and a cleaning unit 18 are provided. The toner is supplied to the developing unit 8 from the toner container 9. The cleaning unit 18 includes a cleaning member such as a blade, a brush, or a polishing roller, and removes and collects toner remaining on the surface of the photoreceptor 5 by the cleaning member.

  When the surface of the photoreceptor 5 is uniformly charged with a predetermined polarity and potential by the charging unit 4, the exposure unit 7 is placed on the photoreceptor 5 based on the image data of the document read by the document reader 6. An electrostatic latent image of the original image is formed.

  The developing unit 8 supplies charged toner to the surface of the photoconductor 5 and develops the electrostatic latent image on the photoconductor 5 to form a toner image. The toner image is transferred onto the paper by the transfer roller 13. The sheet on which the toner image has been transferred is conveyed to a fixing unit 14 disposed above the sheet conveyance path 11. After the toner image is transferred to the paper, the toner remaining on the surface of the photoconductor 5 is cleaned and collected by the cleaning unit 18, and the residual charge on the surface of the photoconductor 5 is removed by a static elimination device (not shown).

  The fixing unit 14 includes a fixing roller 14a having a built-in heat source and a pressure roller 14b, and pressurizes and heats the paper on which the toner image has been transferred by the fixing roller 14a and the pressure roller 14b, thereby converting the toner image on the paper. Melt and fix. The sheet on which the toner image is fixed is conveyed to the upper right in the sheet conveyance path (discharge conveyance path) 11 and is discharged to the in-body sheet discharge unit (discharge tray) 17 by the discharge reverse roller pair 20 of the discharge unit 30.

  A reverse conveyance path 16 is provided that branches from the paper conveyance path 11 between the fixing unit 14 and the discharge reverse roller pair 20. The reverse conveyance path 16 is used when a toner image is fixed on one side of the paper and then formed on the other side of the paper as needed. It covers the periphery of the fixing unit 14, further extends downward between the sheet conveyance path 11 and the side surface 2 a of the apparatus main body 2, and merges with the sheet conveyance path 11 near the registration roller pair 12.

  When performing double-sided printing, the paper on which the toner image is fixed on one side of the paper is discharged to the in-body paper discharge unit 17 while the branch portion between the paper conveyance path 11 and the reverse conveyance path 16 is moved to the rear of the paper. The discharge reversing roller pair 20 is reversely rotated at the timing when the end passes. As a result, the paper is switched back and sent to the reverse conveyance path 16, and is conveyed again from the reverse conveyance path 16 to the registration roller pair 12 of the paper conveyance path 11 with the printing surface of the paper turned upside down. Thereafter, when the toner image is transferred to the other side of the sheet by the image forming unit 3, the sheet is fixed by the fixing unit 14 and discharged to the in-body sheet discharge unit 17.

  FIG. 2 is a cross-sectional perspective view showing the structure around the discharge portion of the image forming apparatus according to the embodiment of the present invention. 2 shows a state viewed from the back side of the sheet of FIG.

  As shown in FIGS. 2 and 3, the discharge unit 30 is provided with a plurality of discharge reversing roller pairs 20 that nip and convey a sheet. Each discharge reversing roller pair 20 includes a driving roller 21 disposed on the upper side of the sheet conveyance path 11 and a driven roller 22 disposed on the lower side. The plurality of drive rollers 21 are fixed to the first rotation shaft 21a and are arranged at predetermined intervals along the direction in which the first rotation shaft 21a extends (paper width direction, left-right direction in FIG. 3). Yes. The plurality of driven rollers 22 are fixed to the second rotating shaft 22a, and are arranged at predetermined intervals along the direction in which the second rotating shaft 22a extends (paper width direction).

  The first rotation shaft 21 a is rotatably supported by an upper guide member (holding unit) 31 that constitutes the upper surface of the paper transport path 11 in the discharge unit 30. The second rotation shaft 22 a is rotatably supported by a lower guide member 32 that constitutes the lower surface of the paper transport path 11 in the discharge unit 30. The second rotating shaft 22a is urged upward by a compression coil spring 33 (see FIG. 4) disposed on the lower guide member 32.

  As shown in FIGS. 4 and 5, guide members 41 and 42 are provided in a direction opposite to the paper discharge direction (discharge direction, arrow X direction) of the upper guide member 31 and the lower guide member 32. The guide member 41 and the lower guide member 32 constitute a part of the sheet conveyance path 11, and the guide members 41 and 42 constitute a part of the reverse conveyance path 16.

  The discharge unit 30 is provided with a plurality of resin-made seating members 50 that are disposed on the upper side of the paper transport path 11 and project downward in the paper transport path 11 (in the recording medium thickness direction). The plurality of seating members 50 are arranged at predetermined intervals along the paper width direction. Here, as shown in FIG. 3, the seating member 50 and the discharge reversing roller pair 20 are arranged in the paper width direction. Alternatingly arranged.

  The seating member 50 is disposed so as to protrude downward from the nip portion of the discharge reversing roller pair 20, so that it is in sliding contact with the paper that is nipped and conveyed by the discharge reversing roller pair 20, and the paper conveyance direction (arrow) It is possible to give the paper a waist by deforming the paper into a wave shape in a cross section perpendicular to the (XX ′ direction).

  As shown in FIG. 6, the seating member 50 includes a sliding contact portion 51 that is in sliding contact with the paper and four engagement portions 52. The engaging portion 52 is disposed on the downstream side in the paper discharge direction (left side in FIG. 4) with respect to the sliding contact portion 51, and on the upstream side in the paper discharge direction with respect to the sliding contact portion 51 (see FIG. 4). 4 on the right side) of the second engagement portion 52b. The first engagement portion 52a is disposed closer to the sliding contact portion 51 than the second engagement portion 52b in the paper transport direction (arrow XX ′ direction). The first engaging portion 52a and the second engaging portion 52b are provided in pairs so as to protrude on both sides in the paper width direction. In the present embodiment, the first engaging portion 52a is formed in a circular shape when viewed from the paper width direction, and the second engaging portion 52b is formed in a substantially rectangular shape when viewed from the paper width direction.

  The lowering member 50 is movably held by the upper guide member 31. The upper guide member 31 is formed with four guide grooves (guide portions) 34 with which the four engagement portions 52 are engaged. The guide groove 34 includes two first guide grooves (first guide portions) 34a that engage with the first engagement portion 52a and two second guide grooves (second guides) that engage with the second engagement portion 52b. Part) 34b.

  The first guide groove 34a and the second guide groove 34b are formed so as to extend in the direction away from the paper (upward) toward the upstream side in the paper discharge direction (right side in FIG. 4). In the present embodiment, the first guide groove 34a and the second guide groove 34b are formed to extend at an equal inclination angle (about 30 °) with respect to the horizontal plane.

  In the image forming apparatus 100, when the discharge reversing roller pair 20 rotates forward and the paper is conveyed in the paper discharge direction (left direction in FIG. 4), the sliding contact portion 51 is a frictional force from the paper in the paper discharge direction. Receive. For this reason, the 1st engaging part 52a and the 2nd engaging part 52b are arrange | positioned in the lower left position (1st position) of FIG. 4 of the 1st guide groove 34a and the 2nd guide groove 34b. At this time, the waisting member 50 projects into the paper transport path 11 to give the paper a waist.

  On the other hand, when the discharge reversing roller pair 20 rotates in the reverse direction and the paper is conveyed in the reverse direction (the direction opposite to the paper discharge direction, the right direction in FIG. 5), the sliding contact portion 51 moves from the paper in the reverse direction. Receive friction. Therefore, the first engaging portion 52a and the second engaging portion 52b are translated in the upper right direction in FIG. 5 along the first guide groove 34a and the second guide groove 34b, and the upper right position (second position). Placed in. At this time, since the seating member 50 is retracted in the direction away from the sheet, it is possible to suppress the waist from being imparted to the sheet.

  In the present embodiment, as described above, the seating member 50 is disposed in the sheet conveyance path 11 by the frictional force received from the sheet when the discharge reversing roller pair 20 rotates forward and the sheet is conveyed in the sheet discharge direction. Is disposed at a first position protruding in the sheet thickness direction. Accordingly, when the paper is discharged to the in-body paper discharge unit 17 by the discharge reversing roller pair 20, the waist is given to the paper by the seating member 50. Therefore, the sheets are stacked in an orderly manner on the in-body discharge unit 17.

  On the other hand, the seating member 50 moves in the reverse direction along the guide groove 34 by the frictional force received from the paper when the discharge reversing roller pair 20 rotates reversely and the paper is conveyed in the reverse direction. It is arranged at the second position where the amount of protrusion into the paper transport path 11 is small compared to the first position. Accordingly, when the paper is transported toward the reverse transport path 16 by the discharge reverse roller pair 20 in order to perform image forming processing on both sides of the paper, the seating member 50 is moved from the first position to the second position. Since it retracts, it is possible to suppress the waist from being applied to the sheet by the seating member 50. For this reason, it is possible to suppress the generation of abnormal noise when the sheet passes through the curved portion of the reverse conveyance path 16.

  In addition, since it is not necessary to provide a drive unit that moves the seating member 50 in the direction of moving toward and away from the paper, an increase in the number of parts can be suppressed.

  Further, as described above, the engaging portion 52 is disposed on the upstream side in the paper discharge direction from the first engaging portion 52 a disposed on the downstream side in the paper discharge direction from the sliding contact portion 51. The guide groove 34 includes a first guide groove 34a that engages with the first engagement part 52a, and a second guide groove 34b that engages with the second engagement part 52b. ,including. Thereby, the seating member 50 can be easily and stably held by the upper guide member 31.

  Further, as described above, the first guide groove 34a and the second guide groove 34b are formed so as to extend in the direction away from the sheet toward the upstream side in the paper discharge direction. Thus, when the seating member 50 moves upstream in the paper discharge direction due to the frictional force that the sliding contact portion 51 receives from the paper when the paper is transported toward the reverse transport path 16, the seating member 50 is Can be easily moved away from the head. In addition, the first guide groove 34a that engages with the first engaging portion 52a closer to the sliding contact portion 51 in the paper transport direction is formed to extend in the direction away from the paper toward the upstream side in the paper discharge direction. . As a result, the portion close to the sliding contact portion 51 (the first engagement portion 52a) can be moved in the direction away from the paper, so even if the movement distance of the first engagement portion 52a is shortened, The sliding contact portion 51 can be sufficiently moved in the direction away from the paper.

  Further, as described above, both the first guide groove 34a and the second guide groove 34b are formed so as to extend in the direction away from the paper toward the upstream side in the paper discharge direction. As a result, the seating member 50 can be moved in a direction away from the paper while being translated, so that the first guide groove 34a and the second guide groove 34b can be formed short.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a monochrome copying machine has been shown, the present invention is not limited to this. Needless to say, the present invention can be applied to various image forming apparatuses provided with a plurality of backrest members for imparting waist to a recording medium, such as a color copying machine, a monochrome printer, a color printer, a digital multifunction peripheral, and a facsimile machine.

  Moreover, in the said embodiment, although the 1st guide groove 34a and the 2nd guide groove 34b were formed so that it might extend with an equal inclination angle with respect to a horizontal surface, and the example which moved the seating member 50 was shown, this invention is shown. Not limited to this. For example, as in the first modification of the present invention shown in FIG. 7, one of the first guide groove 34a and the second guide groove 34b (here, the first guide groove 34a) is inclined with respect to the horizontal plane, and the first The other of the guide groove 34a and the second guide groove 34b (here, the second guide groove 34b) may be formed to extend in the horizontal direction. In this case, it is preferable to form the second guide groove 34b that engages with the second engagement portion 52b that is farther from the sliding contact portion 51 in the paper transport direction so as to extend in the horizontal direction. If comprised in this way, since only the part by the side of the 1st engaging part 52a of the seating member 50 should just be lifted, even if it is a case where the frictional force between the sliding contact part 51 and a paper is comparatively small The sliding contact portion 51 can be easily moved in the direction away from the paper (upward direction). In the configuration of FIG. 7, since the rotation operation around the second engagement portion 52 b is also added, it is preferable that the second engagement portion 52 b is formed in a circular shape when viewed from the sheet width direction. Further, in the configuration of FIG. 7, only the portion on the first engagement portion 52a side of the seating member 50 is lifted, so that the first guide groove 34a is formed in order to move the sliding contact portion 51 sufficiently upward. It is necessary to form longer than in the above embodiment.

  In the above embodiment, an example in which a pair of engaging portions 52 are formed on the upstream side and the downstream side in the paper discharge direction has been described. However, the present invention is not limited to this, and for example, the first embodiment of the present invention illustrated in FIG. As in the second modification, only one pair of engaging portions 52 may be formed. In this case, the seating member 50 may be translated by forming the engaging portion 52 so as to extend in the same direction as the guide groove 34.

  Moreover, although the example which does not provide the urging member which urges | biases the lowering member 50 below was shown in the said embodiment, this invention is not restricted to this, Energizing which urges the lowering member 50 below. A biasing member (such as a compression spring) may be provided.

  In the above-described embodiment, the example in which the seating member 50 is disposed on the upper side of the sheet conveyance path 11 has been described. However, the present invention is not limited thereto, and the seating member 50 is disposed on the lower side of the sheet conveyance path 11. May be. In this case, an urging member (compression spring or the like) that urges the seating member 50 upward may be provided.

  Further, a configuration obtained by appropriately combining the configurations of the above-described embodiment and modification examples is also included in the technical scope of the present invention.

3 Image forming unit 5 Photoconductor (image carrier)
11 Paper transport path (discharge transport path)
14 Fixing part 16 Reverse conveyance path 20 Discharge reverse roller pair 30 Discharge part 31 Upper guide member (holding part)
34 Guide groove (guide part)
34a First guide groove (first guide portion)
34b Second guide groove (second guide portion)
DESCRIPTION OF SYMBOLS 50 Seating member 51 Sliding contact part 52 Engagement part 52a 1st engagement part 52b 2nd engagement part 100 Image forming apparatus

Claims (6)

An image forming unit for transferring a toner image formed on the image carrier onto a recording medium;
A fixing unit that melts and fixes the toner image transferred onto the recording medium in the image forming unit;
A discharge unit for discharging the recording medium on which the toner image is fixed by the fixing unit;
A discharge conveyance path for conveying the recording medium from the fixing unit to the discharge unit;
A reversing conveyance path that is provided so as to be connected to the upstream side in the recording medium discharge direction of the discharge unit, and reverses the recording medium on which image formation has been performed on one side and re-transfers the recording medium to the image forming unit;
A discharge reversing roller pair that is provided in the discharge portion so as to be able to rotate forward and backward, discharges the recording medium by forward rotation, and transports the recording medium toward the reverse transport path by reverse rotation,
Provided in the discharge section, protrudes in the thickness direction of the recording medium in the discharge conveyance path, slidably contacts the recording medium nipped by the pair of discharge reversing rollers, and waves the recording medium in a cross section perpendicular to the recording medium conveyance direction. A plurality of waist-attaching members that impart waist to the recording medium by being deformed into a shape;
A holding part that is provided in the discharge part and has a guide part that holds the seating member movably;
With
The waisting member is
When the discharge reversing roller pair rotates forward and the recording medium is conveyed in the discharge direction, the friction force received from the recording medium is arranged at a first position protruding in the recording medium thickness direction in the discharge conveyance path,
When the discharge reversing roller pair rotates reversely and the recording medium is conveyed in the reversing direction, it moves in the reversing direction along the guide portion by the frictional force received from the previous recording medium, and compared with the first position. An image forming apparatus, wherein the image forming apparatus is disposed at a second position where the amount of protrusion into the discharge conveyance path is small.   The image forming apparatus according to claim 1, wherein the seating member includes a sliding contact portion that is in sliding contact with the recording medium, and an engagement portion that engages with a guide portion of the holding portion. The engagement portion includes a first engagement portion disposed downstream of the sliding contact portion in the discharge direction and a second engagement portion disposed upstream of the slide contact portion in the discharge direction. ,
The said guide part contains the 1st guide part engaged with the said 1st engaging part, and the 2nd guide part engaged with the said 2nd engaging part, The Claim 2 characterized by the above-mentioned. Image forming apparatus.   The guide portion that engages at least the engagement portion closer to the sliding contact portion in the recording medium conveyance direction of the first engagement portion and the second engagement portion is directed toward the upstream side in the discharge direction. The image forming apparatus according to claim 3, wherein the image forming apparatus is formed to extend in a direction away from the recording medium.   5. The image forming apparatus according to claim 4, wherein both the first guide portion and the second guide portion are formed so as to extend in a direction away from the recording medium toward the upstream side in the discharge direction. .   The guide portion that engages with the engagement portion farther from the sliding contact portion in the recording medium conveyance direction of the first engagement portion and the second engagement portion is formed to extend in the horizontal direction. The image forming apparatus according to claim 4, wherein:

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