JP2015098394A - Image formation device and attachment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of image formation failure in an image formation device capable of double face printing.SOLUTION: An attachment 30 is possible to be fitted which is intended to bias a sheet that is placed to a first side guide 23 side. Thus, in a state where the attachment 30 is fitted, a sheet that is transported from a placement part 17A is, compared with a case of the attachment 30 being not fitted, transported to an image formation part in a state being biased to a re-transportation guide side, in other words, to one end side in width direction. Therefore, even in a case where the dimension in the width direction of the sheet that is re-transportation is small, the sheet can be biased as far as the re-transportation guide while the sheet is present in the re-transportation part, in other words, before the sheet reaches the image formation part. In addition, occurrence of image formation failure can be suppressed.

Description

  The present invention relates to an image forming apparatus capable of forming images on both front and back surfaces of a sheet, and an attachment assembled to the image forming apparatus.

  For example, the invention described in Patent Document 1 is an image forming apparatus having a function of forming images on both front and back sides of a sheet (hereinafter also referred to as a double-sided printing function). In the image forming apparatus according to the invention, images are formed on both the front and back surfaces as follows.

  That is, when an image is formed on the surface, the sheet is conveyed in a state where the position in the width direction of the sheet is determined with reference to the center in the width direction. When an image is formed on the back surface, the sheet is conveyed in a state where the position in the width direction of the sheet is determined with reference to the end in the width direction. The width direction is a direction orthogonal to the thickness direction of the conveyed sheet and the conveyance direction.

JP 2002-104694 A

  In the invention described in Patent Document 1, when an image is formed on the back surface, the end in the width direction serves as a reference for the position in the width direction. A skew portion is provided to bring the sheet to be moved toward the end in the width direction.

  However, if the width-direction dimension of the sheet being re-conveyed is small (for example, A4 size or less), the sheet is present while the sheet exists in the re-conveyance unit, that is, before the sheet reaches the image forming unit. There is a possibility that a state where it is not possible to approach the end in the width direction may occur.

When this state occurs, an image formation defect occurs in which an image formed on the sheet shifts from a position where it should originally be formed.
In view of the above points, an object of the present invention is to suppress the occurrence of the image formation failure.

  In order to achieve the above object, the present invention is an image forming apparatus capable of forming images on both the front and back sides of a sheet. The image forming unit (5) forms an image on a sheet, and the image forming unit ( 5) The placement unit (17A) on which the sheet to be conveyed is placed and the placement unit (17A) are provided on the placement unit (17A) to contact the sheet from both sides in the width direction orthogonal to the conveyance direction to guide the conveyance of the sheet. And a first side guide (23) and a second side guide (24) that are displaceable in the width direction in conjunction with each other, the first side guide (23) and the other end in the width direction located at one end in the width direction. A second side guide (24) positioned on the side, a re-conveying unit (21) for re-conveying a sheet with an image formed on one sheet surface to the entrance side of the image forming unit (5), and a re-conveying unit ( 21) is provided at one end in the width direction and is transported. A re-conveying guide (21A) that contacts one end in the width direction of the sheet and guides re-conveying of the sheet, and a skew that is provided in the re-conveying unit (21) and moves the conveyed sheet toward the re-conveying guide (21A) Attachment (30) provided to at least one of the portion (21B), the second side guide (24), and the placement portion (17A) and for bringing the placed sheet to the first side guide (23) side It is provided with the to-be-attached part (24A, 24B) which can attach.

  Thereby, in this invention, the attachment (30) for approaching the sheet | seat to be mounted to the 1st side guide (23) side can be attached. In the state where the attachment (30) is attached, the sheet conveyed from the placement portion (17A) is closer to the re-conveying guide (21A) side, that is, in the width direction than when the attachment (30) is not attached. The sheet is conveyed to the image forming unit (5) in a state of being close to one end side.

  Therefore, even when the width-direction dimension of the sheet to be re-transported is small, the sheet is removed while the sheet exists in the re-conveyance unit (21), that is, before the sheet reaches the image forming unit (5). The re-conveying guide (21A) can be approached. As a result, the occurrence of the image formation failure can be suppressed.

  In the present invention, the attachment (30) is not an essential requirement of the invention. That is, the present invention has a configuration to which the attachment (30) can be attached, and an image forming apparatus that does not include the attachment (30) at the time of shipment from the manufacturer, and an image forming apparatus that includes the attachment (30) from the time of shipment from the manufacturer. Either of these may be used.

  Incidentally, the reference numerals in parentheses for each of the above means are examples showing the correspondence with the specific means described in the embodiments described later, and the present invention is indicated by the reference numerals in the parentheses of the above respective means. It is not limited to specific means.

1 is a central sectional view of an image forming apparatus 1 according to an embodiment of the present invention. 3 is a perspective view of a re-transport unit 21. FIG. 3 is a perspective view of a paper feed tray 17. FIG. (A) And (b) is a figure which shows the 1st side guide 23, the 2nd side guide 24, and the attachment 30. FIG. (A) is a top view of the 2nd side guide 24 with which attachment 30 was equipped. FIG. 5B is a left side view of FIG. FIG. 5C is a top view of FIG. FIG. 5D is a bottom view of FIG. (A), (b) and (c) is explanatory drawing which shows attachment of the attachment 30. FIG. (A) is a perspective view which shows the attachment 30, the 2nd side guide 24, and the control part 17C. FIG. 7B is a view of the restriction portion 17 </ b> C and the convex portion 30 </ b> G viewed from the lower surface side of the paper feed tray 17. (A) is a top view of the attachment 30 and the 2nd side guide 24 in the state shown to Fig.6 (a). FIG. 6B is a top view of FIG.

  The “embodiment of the invention” described below shows an example of the embodiment. In other words, the invention specific items described in the claims are not limited to the specific means and structures shown in the following embodiments.

  In this embodiment, the present invention is applied to a monochrome image forming apparatus. The arrows and the like indicating the directions given to the drawings are described for easy understanding of the relationship between the drawings. The present invention is not limited to the directions given in the drawings.

  At least one member or part described with at least a reference numeral is provided, except where “plurality”, “two or more”, and the like are omitted. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1. Overview of Image Forming Apparatus As shown in FIG. 1, an image forming unit 5 that forms an image on a sheet such as a recording sheet is housed in a housing 3 of the image forming apparatus 1. The image forming unit 5 according to the present embodiment is an electrophotographic system having a process cartridge 7, an exposure device 9, a fixing device 11, and the like.

  The process cartridge 7 includes a photosensitive drum 7A, a charger 7B, a developer 7C, and the like. The photosensitive drum 7A carries a developer image transferred to the sheet. The charger 7B charges the photosensitive drum 7A. The exposure device 9 forms an electrostatic latent image on the charged photosensitive drum 7A. The developing device 7C supplies a developer to the photosensitive drum 7A to form a developer image.

  A transfer unit 10 is disposed at a position facing the photosensitive drum 7A. The transfer unit 10 transfers the developer image carried on the photosensitive drum 7A to a sheet. The developer image transferred to the sheet is heated by the fixing device 11 and fixed on the sheet.

  A pair of paper discharge rollers 12 is provided downstream of the fixing device 11 in the sheet conveying direction. The sheet on which the image is formed is discharged by a pair of paper discharge rollers 12 to a paper discharge tray 3A provided on the upper surface of the housing 3.

  A feeder mechanism 19 is provided upstream of the photosensitive drum 7A in the sheet conveying direction. The feeder mechanism 19 sends out the sheets placed on the paper feed tray 17 one by one toward the image forming unit 5 side.

  The feeder mechanism 19 includes a pickup roller 19A, a separation roller 19B, a separation pad 19C, and the like. The pickup roller 19A sends the sheet placed on the paper feed tray 17 to the separation roller 19B and the separation pad 19C side.

  The separation roller 19 </ b> B and the separation pad 19 </ b> C separate the sheets one by one when a plurality of sheets are sent out, and convey the separated sheets to the image forming unit 5 side. The paper feed tray 17 includes a placement unit 17 </ b> A on which a sheet conveyed to the image forming unit 5 is placed. Details of the paper feed tray 17 will be described later.

  The paper feed tray 17 is detachable from the apparatus value main body. The apparatus main body refers to a portion that is not attached or detached or replaced by a user such as the housing 3 or the main frame (not shown). The main frame is a substantially plate-shaped strength member disposed at both ends with the process cartridge 7 interposed therebetween.

  The re-conveying unit 21 is a re-conveying unit that re-conveys a sheet having an image formed on one sheet surface to the entrance side of the image forming unit 5. That is, when images are formed on both the front and back surfaces of a sheet, first, images are formed on one surface (front surface).

  The sheet on which the image is formed on the surface is conveyed to the re-conveying unit 21 with the conveying direction reversed by the pair of paper discharge rollers 12. Since the back surface of the sheet supplied from the re-conveying unit 21 to the image forming unit 5 faces the photosensitive drum 7A, an image is formed on the back surface.

  As shown in FIG. 2, the reconveying unit 21 includes a reconveying guide 21 </ b> A and a skew feeding unit 21 </ b> B. The re-conveying guide 21A is a wall surface that is provided on one end side in the width direction of the re-conveying unit 21 and extends along the re-conveying direction, and contacts the one end in the width direction of the re-conveyed sheet to re-convey the sheet. invite.

  The width direction refers to a direction orthogonal to the sheet thickness direction among directions orthogonal to the sheet conveyance direction. In the present embodiment, the width direction coincides with the left-right direction of the image forming apparatus 1, and one end in the width direction coincides with the left end side of the image forming apparatus 1.

  The skew feeding portion 21B brings the re-conveyed sheet to the re-conveyance guide 21A side. The skew feeding portion 21B according to the present embodiment is configured by a conveyance roller that rotates in contact with the sheet. The conveying roller, that is, the skew feeding portion 21B applies a conveying force in the direction to the re-conveying guide 21A to the re-conveyed sheet.

  The pair of reconveying rollers 21 </ b> C are conveying rollers that send out the sheet brought near the reconveying guide 21 </ b> A toward the entrance of the image forming unit 5. A driving force for rotating the pair of re-conveying rollers 21C and the skew feeding portion 21B is supplied from the apparatus main body. The drive shafts 21D and 21E transmit driving force to the pair of re-conveying rollers 21C.

2. 2. Paper Feed Tray 2.1 Configuration of Paper Feed Tray As shown in FIG. 3, the placement portion 17A is a portion that constitutes the bottom plate portion of the paper feed tray 17, and a portion where sheets are stacked and placed in the vertical direction. It is. The pressing plate 17B displaces the sheet toward the pickup roller 19A, thereby suppressing the contact pressure between the pickup roller 19A and the sheet from becoming less than a predetermined contact pressure.

  The mounting portion 17A is provided with a first side guide 23 and a second side guide 24. The 1st side guide 23 is provided in the width direction one end (this embodiment left end) side of 17 A of mounting parts. The second side guide 24 is provided on the other end in the width direction (right end in the present embodiment) of the placement portion 17A.

  The first side guide 23 contacts the one end in the width direction of the sheet placed on the placing portion 17A (the left end in the present embodiment) to guide the sheet conveyance. The second side guide 24 contacts the other end in the width direction of the sheet placed on the placement unit 17A (the right end in the present embodiment) to guide the sheet conveyance.

  The first side guide 23 and the second side guide 24 can be displaced in the width direction in conjunction with each other, and are located in a portion that is always symmetrical with respect to the center in the width direction of the placement portion 17A. For this reason, the sheet placed on the placement portion 17A does not depend on the size of the sheet, and the position of the center in the width direction is always located at the same position with respect to the placement portion 17A. It is conveyed toward 5.

  Therefore, when an image is formed on the surface of the sheet, that is, when the sheet is supplied from the placement unit 17A to the image forming unit 5, the sheet is conveyed with reference to the center in the width direction. When an image is formed on the back side of the sheet, that is, when the sheet is supplied from the reconveying unit 21 to the image forming unit 5, the sheet is moved toward the reconveying guide 21A by the skew feeding unit 21B. The sheet is conveyed with one end in the width direction as a reference.

2.2 Attachment As shown in FIG. 4A, an attachment 30 can be attached to the second side guide 24. As shown in FIG. 4B, in the state where the attachment 30 is attached to the second side guide 24, the attachment 30 is connected to the second side guide 24 at the center in the width direction of the sheet placed on the placement portion 17 </ b> A. Compared with the case where it is not attached, the first side guide 23 side, that is, the left end is approached.

  That is, when the attachment 30 is not attached to the second side guide 24, the center in the width direction of the sheet placed on the placement portion 17A is the position of the center in the width direction of the placement portion 17A, that is, the first side guide. 23 and the second side guide 24.

  When the attachment 30 is attached to the second side guide 24, the width direction end (left end in the present embodiment) of the sheet placed on the placement portion 17A comes into contact with the first side guide 23, and The other end in the width direction (the right end in the present embodiment) is in contact with the attachment 30.

  For this reason, in the state where the attachment 30 is mounted on the second side guide 24, the center in the width direction of the sheet placed on the placement portion 17A is the center position between the attachment 30 and the first side guide 23, that is, the placement. The portion 17A is located at a position shifted from the center in the width direction to one end in the width direction (left end in the present embodiment).

  As shown in FIGS. 5A to 5D, the user attaches the attachment 30 via the first attached portion 24 </ b> A and the pair of second attached portions 24 </ b> B provided on the second side guide 24. The second side guide 24, that is, the paper feed tray 17 can be detachably attached.

  The main body portion 30A of the attachment 30 is provided with a first attachment portion 30B and a pair of second attachment portions 30C. The main body 30A is a part for contacting the other end in the width direction of the sheet and bringing the sheet to the first side guide 23 side.

  The first attachment portion 30B engages with the first attached portion 24A. Each of the pair of second mounting portions 30C engages with each second mounted portion 24B. As shown in FIG. 5A, the first mounting portion 30B is configured by a hook having a protrusion 30D and a locking portion 30E and curved in an L shape.

  The protrusion 30D is a portion protruding from the main body 30A. The locking part 30E is a part that extends from the tip of the protrusion 30D in a direction orthogonal to the protruding direction of the protrusion 30D. As shown in FIG. 6C, the second mounting portion 30C is also configured by a hook having a protrusion 30D and a locking portion 30E and curved in an L shape.

  The first attachment portion 30B and the second attachment portion 30C are integrally formed with resin together with the main body portion 30A. Note that an engagement protrusion 30F for maintaining the engagement state with the first attached portion 24A is provided in the locking portion 30E of the first attachment portion 30B by integral molding.

  As shown in FIG. 5A, the first attached portion 24 </ b> A is provided on a wall-shaped reinforcing rib provided at the end of the second side guide 24. The pair of second attached portions 24 </ b> B includes a through hole provided on a surface of the second side guide 24 parallel to the placement portion 17 </ b> A and a plate surface around the through hole.

  As shown in FIG. 7A, the placement portion 17A is provided with a restriction portion 17C that restricts the attachment 30 from being displaced in the width direction. The restricting portion 17 </ b> C is configured by a concave portion that engages with a convex portion 30 </ b> G provided on the attachment 30. As shown in FIG. 7B, the concave portion, that is, the restricting portion 17C is configured by a rectangular through hole penetrating the placement portion 17A.

  Of the through holes constituting the restricting portion 17C, the portion A parallel to the width direction has substantially the same dimensions as the portion B of the convex portion 30G parallel to the width direction. For this reason, when the attachment 30 is attached to the paper feed tray 17, that is, when the attachment 30 is attached to the second side guide 24, the convex portion 30G is fitted and engaged with the restricting portion 17C which is a concave portion. 30 displacements in the width direction are restricted.

  Since the restricting portion 17C, that is, the concave portion is provided in the placement portion 17A, the position of the restricting portion 17C does not move. In the present embodiment, the attachment 30 is attached to the second side guide 24. Therefore, the user can attach the attachment 30 to the paper feed tray 17 only when the second side guide 24 is in a predetermined position.

  That is, in the present embodiment, the user can attach the attachment 30 to the paper feed tray only when the second side guide 24 is positioned at a position where the convex portion 30G of the attachment 30 and the restricting portion 17C of the placement portion 17A can be engaged. 17 (second side guide 24).

  Only when the second side guide 24 is in a predetermined position, the restricting portion 17C engages with the attachment 30 to restrict the attachment 30 from being displaced in the width direction.

2.3 Attachment Attachment FIGS. 6 (a) to 6 (b) illustrate the relationship between the second attachment portion 30C and the second attached portion 24B, with a part of the main body portion 30A as a cross section. . As shown in FIG. 6B, the second attached portion 24B has a through hole through which the locking portion 30E can pass.

  When the user attaches the attachment 30, first, as shown in FIG. 6A, the attachment 30 is moved from the upper side to the lower side with respect to the second side guide 24. At this time, as shown in FIGS. 8A and 8B, the locking portion 30E of the first mounting portion 30B is elastically displaced so as to be separated from the main body portion 30A.

  Next, as shown in the order of FIG. 6 (b) → FIG. 6 (c), the user is directed from the protrusion 30D toward the leading end of the locking portion 30E, that is, from the rear side toward the front side. Next, the attachment 30 is moved relative to the second side guide 24.

  Thereby, as shown in FIG. 6 (c), each of the pair of second mounting portions 30C engages with each second mounted portion 24B, and as shown in FIG. 5 (a), the first mounting portion 30B Engages with the first attached portion 24A.

3. Features of Image Forming Apparatus and Attachment According to this Embodiment In the image forming apparatus 1 according to this embodiment, an attachment 30 for attaching a sheet to be placed to the first side guide 23 side is attached to the paper feed tray 17. it can.

  In a state where the attachment 30 is attached to the paper feed tray 17, the sheet conveyed from the placement unit 17 </ b> A is closer to the re-conveyance guide 21 </ b> A side, that is, one end side in the width direction than when the attachment 30 is not attached. In this state, it is conveyed to the image forming unit 5.

  Accordingly, even when the width-direction dimension of the sheet being re-transported is small, the sheet is re-conveyed while the sheet is present in the re-conveying unit 21, that is, before the sheet reaches the image forming unit 5. Can get up to. As a result, the occurrence of the image formation failure can be suppressed.

  For example, if the attachment 30 having the thickness of the main body 30A of 19 mm is attached with the positions of the first side guide 23 and the second side guide 24 set so as to correspond to the A4 size of 214 mm in the width direction, It can also accommodate 16K size sheets with dimensions of 195 mm.

  The present embodiment is characterized in that a restriction portion 17 </ b> C that restricts displacement of the attachment 30 in the width direction is provided. Thereby, when the attachment 30 is attached to the second side guide 24, the attachment 30 is restricted from moving in the width direction, so that the seat can be reliably placed at an appropriate position.

  The present embodiment is characterized in that the attachment 30 can be attached to the placement portion 17A only when the second side guide 24 is at a predetermined position. Thereby, even if it is a case where a user attaches attachment 30, attachment 30 can be attached to the position preset at the design stage.

(Other embodiments)
The image forming apparatus 1 according to the above-described embodiment includes the attachment 30 from the time of shipment from the manufacturer. However, in the present invention, the attachment 30 is not an essential requirement of the invention. That is, the present invention may be an image forming apparatus that can be attached to the attachment 30 and does not include the attachment 30 at the time of shipment from the manufacturer.

  In the above-described embodiment, the first attached portion 24A and the second attached portion 24B are both provided in the second side guide 24. However, the present invention is not limited to this. One of the mounted portion 24A and the second mounted portion 24B is provided on the second side guide 24 and the other is provided on the mounting portion 17A, or any of the mounted portions 24A and 24B is also provided on the mounting portion 17A. Etc.

In the above-described embodiment, the restricting portion 17C is provided, but the present invention is not limited to this, and the restricting portion 17C may be eliminated.
In the above-described embodiment, the convex portion 30G is provided on the attachment 30, and the restricting portion 17C that is a concave portion is provided on the placement portion 17A. However, the present invention is not limited to this.

  That is, for example, (1) the convex portion 30G is provided on the mounting portion 17A and the concave portion regulating portion 17C is provided on the attachment 30, or (2) the convex portion 30G is provided on the attachment 30 and the concave portion. The restriction part 17C may be provided on the second side guide 24, or (3) the convex part 30G may be provided on the second side guide 24, and the restriction part 17C that is a concave part may be provided on the attachment 30.

  In the case of the above configuration (2) or (3), the attachment 30 can be attached to the paper feed tray 17 even when the second side guide 24 is not in a predetermined position. Become.

  Further, the present invention is not limited to the above-described embodiment as long as it matches the gist of the invention described in the claims.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 3 ... Housing | casing 3A ... Paper discharge tray 5 ... Image forming part 7 ... Process cartridge 7A ... Photosensitive drum 7B ... Charger 7C ... Developing device 9 ... Exposure device 10 ... Transfer part 11 ... Fixing device 12 ... Exhaust Paper roller 17 ... Feed tray 17A ... Placement unit 17B ... Pressing plate 17C ... Restriction unit 19 ... Feeder mechanism 19A ... Pickup roller 19B ... Separation roller 19C ... Separation pad 21 ... Re-conveying unit 21A ... Re-conveying guide 21B ... Skew Part 21C ... Re-conveying roller 21D ... Drive shaft 23 ... First side guide 24 ... Second side guide 24A ... First attached part 24B ... Second attached part 30 ... Attachment 30A ... Main body part 30B ... First attachment part 30C ... 2nd attachment part 30D ... Projection part 30E ... Locking part 30G ... Projection part 30F ... Engagement protrusion

Claims (12)

In an image forming apparatus capable of forming images on both front and back sides of a sheet,
An image forming unit for forming an image on a sheet;
A placement unit on which a sheet conveyed to the image forming unit is placed;
A first side guide and a second side guide which are provided in the mounting portion and are capable of guiding the conveyance of the sheet by contacting the sheet from both sides in the width direction orthogonal to the conveyance direction, and displaceable in the width direction in conjunction with each other. A first side guide located on one end side in the width direction and a second side guide located on the other end side in the width direction;
A re-conveying unit that re-conveys a sheet having an image formed on one sheet surface to the entrance side of the image forming unit;
A re-conveying guide that is provided on one end side in the width direction of the re-conveying unit and guides the re-conveying of the sheet by contacting the one end in the width direction of the conveyed sheet;
A skew portion provided in the re-conveying unit, for bringing the conveyed sheet toward the re-conveying guide;
A mounted portion provided on at least one of the second side guide and the mounting portion, and a mounted portion to which an attachment for bringing the seat to be placed toward the first side guide can be mounted. An image forming apparatus comprising the image forming apparatus.   The image forming apparatus according to claim 1, wherein the placement unit is provided with a regulation unit that regulates displacement of the attachment in the width direction when the attachment is attached. .   The image forming apparatus according to claim 2, wherein the restricting portion includes a convex portion or a concave portion that engages with the attachment.   The image forming apparatus according to claim 2, wherein the restricting portion includes a concave portion that engages with a convex portion provided on the attachment. The regulation part is
Only when the second side guide is in a predetermined position, and can be engaged with the attachment; and
The image forming apparatus according to any one of claims 2 to 4, wherein when the attachment is attached, the attachment is restricted from being displaced in the width direction.   The image forming apparatus according to claim 1, wherein the attached portion is provided in the second side guide.   When the sheet is supplied from the placement unit to the image forming unit, the sheet is conveyed with respect to the center in the width direction, and when the sheet is supplied from the re-conveying unit to the image forming unit, the width The image forming apparatus according to claim 1, wherein the sheet is conveyed with reference to one end in the direction. In an image forming apparatus capable of forming images on both front and back sides of a sheet,
An image forming unit for forming an image on a sheet;
A placement unit on which a sheet conveyed to the image forming unit is placed;
A first side guide and a second side guide which are provided in the mounting portion and are capable of guiding the conveyance of the sheet by contacting the sheet from both sides in the width direction orthogonal to the conveyance direction, and displaceable in the width direction in conjunction with each other. A first side guide located on one end side in the width direction and a second side guide located on the other end side in the width direction;
A re-conveying unit that re-conveys a sheet having an image formed on one sheet surface to the entrance side of the image forming unit;
A re-conveying guide that is provided on one end side in the width direction of the re-conveying unit and guides the re-conveying of the sheet by contacting the one end in the width direction of the conveyed sheet;
A skew portion provided in the re-conveying unit, for bringing the conveyed sheet toward the re-conveying guide;
An attachment provided on the second side guide for bringing the seat to be placed toward the first side guide;
An attachment portion provided on a main body portion of the attachment for attaching the attachment to at least one of the second side guide and the placement portion, a protrusion protruding from the main body portion, and a protrusion of the protrusion An image forming apparatus comprising: an attachment portion that has an engaging portion that extends in a direction orthogonal to the protruding direction of the protrusion from the tip, and is curved in an L shape.   The mounting portion restricts the attachment from being displaced in the width direction and allows the attachment to be displaced in the extending direction of the locking portion when the attachment is attached. The image forming apparatus according to claim 6, wherein the image forming apparatus is provided.   When the sheet is supplied from the placement unit to the image forming unit, the sheet is conveyed with respect to the center in the width direction, and when the sheet is supplied from the re-conveying unit to the image forming unit, the width The image forming apparatus according to claim 8, wherein the sheet is conveyed with reference to one end in the direction. An image forming unit for forming an image on a sheet;
A placement unit on which a sheet conveyed to the image forming unit is placed;
A first side guide and a second side guide which are provided in the mounting portion and are capable of guiding the conveyance of the sheet by contacting the sheet from both sides in the width direction orthogonal to the conveyance direction, and displaceable in the width direction in conjunction with each other. A first side guide located on one end side in the width direction and a second side guide located on the other end side in the width direction,
A re-conveying unit that re-conveys a sheet having an image formed on one sheet surface to the entrance side of the image forming unit;
A re-conveying guide that is provided at one end in the width direction of the re-conveying unit and that contacts the one end in the width direction of the conveyed sheet to guide re-conveying of the sheet, and is provided and conveyed in the re-conveying unit An attachment that is applied to an image forming apparatus that includes a skew portion that brings the sheet to the re-conveying guide side,
It has a main body part for bringing the seat to be placed to the first side guide side, and an attachment part for attaching the main body part to at least one of the second side guide and the placement part. Attachment for side guide.   The attachment portion has a protruding portion protruding from the main body portion, and a locking portion extending in a direction orthogonal to the protruding direction of the protruding portion from the tip of the protruding portion, and is curved in an L shape. The attachment according to claim 11, wherein the attachment is characterized.

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