JP6512933B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet conveying apparatus for conveying a sheet in an image forming apparatus such as a copying machine, a printer, and a facsimile, and an image forming apparatus provided with the sheet conveying apparatus.

  In recent years, when forming an image with an image forming apparatus such as a printer or a copier, a wide variety of sheets are used according to the purpose. In particular, there is a demand for using a thick sheet (thick sheet) used for packaging packages and a cover during bookbinding in an image forming apparatus, but when using such a thick sheet with high rigidity (rigidity), curved conveyance There is a problem that jamming (paper jam) is likely to occur in the pass. This is because the sheet guided and conveyed by the conveyance guide in the bending portion of the conveyance path receives a greater resistance during conveyance from the conveyance guide as the curvature radius of the bending portion is smaller, and the sheet is not conveyed. Therefore, measures have been taken to increase the radius of curvature of the curved portion of the transport path to reduce the resistance received from the transport guide when transporting the sheet.

  On the other hand, there is a strong demand for a reduction in the installation area of the image forming apparatus, and it is desirable to reduce the size of the apparatus by reducing the radius of curvature of the curved portion of the conveyance path. Therefore, even if the radius of curvature of the curved portion of the conveyance path is reduced, measures are taken to prevent the occurrence of jams by increasing the sheet conveyance force by increasing the nip pressure of the conveyance roller.

  In addition, since a wide variety of sheets are used in the image forming apparatus, various types of sheets having different thicknesses (stiffnesses) and sizes are respectively stored in a plurality of sheet storage units, and each sheet storage unit as necessary Are configured to feed a sheet from The conveyance paths in which the sheets fed from the sheet storage units are conveyed merge into one conveyance path (merged conveyance path), and the sheets fed from the sheet storage units are merged to form an image forming apparatus. Toward the image forming unit of As such a configuration, for example, there is a configuration in which conveyance paths for conveying a sheet from three directions of upward, downward, and horizontal directions are merged into one combined conveyance path (see Patent Document 1).

JP, 2013-112489, A

  Generally, in a configuration in which conveyance paths from three directions, that is, two directions vertically and one horizontal direction, merge with the merging conveyance path, the upper conveyance path is disposed in the upper conveyance unit, and the lower conveyance path is It is disposed in the lower transport unit. Then, a horizontal transport path is formed between the upper transport unit and the lower transport unit, these transport paths merge at the merging transport path, and the merging transport path is provided in the horizontal pass unit located downstream. It is connected to the direction conveyance path.

  In this configuration, for example, in the case where the upper side conveyance unit and the horizontal pass unit are large and heavy units, the following problems occur. When the upper transport unit and the horizontal pass unit are attached to the main body frame, there is a possibility that distortion of the unit frame and distortion of the main body frame may occur due to the weight (gravity) of the unit. When distortion occurs in each unit and the main body frame, the inter-guide gap (guide gap) between the guide member of the merging conveyance path and the guide member of the upper conveyance unit at the merging portion may be narrowed. Furthermore, there is a possibility that a discontinuous level difference may occur between the merging conveyance path and the conveyance path of the horizontal pass unit. When the gap between guides of the guide member is narrowed or a step is generated between transport paths, resistance against the guide member is increased when a sheet such as thick paper having high rigidity is transported, and jamming tends to occur. .

  An object of the present invention is to provide a sheet conveying apparatus and an image forming apparatus capable of reducing the occurrence of jam without holding a guide gap of a guide member and increasing resistance from the guide member.

  In the sheet conveying apparatus according to the present invention, a first conveying unit that guides a sheet conveyed from a plurality of directions from below with a first guide member and guides the sheet, and an upstream of the first conveying unit in the sheet conveying direction. A second transport unit having a second guide member disposed with the downstream end facing the first guide member and guiding the sheet toward the first transport unit; and a sheet of the first transport unit A third transport member disposed downstream in the transport direction and having a third guide member disposed with the upstream end facing the first guide member, and guiding the sheet guided by the first transport unit downstream A unit, and the first guide member interposed between the downstream end of the first guide member and the second guide member and between the upstream end of the first guide member and the third guide member; Serial gap between the downstream end portion of the second guide member, and characterized in that it comprises, respectively, a guide spacing members to set the distance between the first guide member and the third guide member.

  According to the present invention, the guide gap is properly held in consideration of the bending direction of the guide member due to the unit weight, and even if a sheet such as thick paper is conveyed, occurrence of jam without increasing the resistance acting from the guide member It becomes possible to reduce the

FIG. 1 is a schematic cross-sectional view showing an image forming apparatus provided with a sheet conveying apparatus according to a first embodiment of the present invention. FIG. 2 is an enlarged front view showing a sheet conveying apparatus according to the first embodiment; FIG. 2 is an enlarged perspective view showing a sheet conveying apparatus according to the first embodiment. FIG. 2 is a perspective view showing a merging guide and the like in the sheet conveying apparatus according to the first embodiment. FIG. 5 is a perspective view showing a merging guide and the like in the sheet conveying apparatus according to the first embodiment as viewed from an angle different from FIG. 4; The perspective view which shows the structure of FIG. 3 in the state seen from the back side. FIG. 2 is a perspective view showing a configuration in which a horizontal pass unit according to the first embodiment is fixed to a horizontal pass frame. (A) is sectional drawing which shows the confluence guide etc. in the sheet conveying apparatus which concerns on the 2nd Embodiment of this invention, (b) is a perspective view shown in the state seen from the angle different from (a). FIG. 10 is a perspective view showing a merging guide and the like in the sheet conveying apparatus according to the second embodiment. FIG. 8 is a front view showing a sheet conveying apparatus according to a comparative example in an enlarged manner.

First Embodiment
Hereinafter, an image forming apparatus such as a copying machine or a printer will be described as an example with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions, The scope of the invention is not intended to be limited thereto. FIG. 1 is a schematic cross-sectional view showing an image forming apparatus 90 provided with a sheet conveying apparatus 16 according to the present embodiment.

  FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus 90 according to the first embodiment. In the following description, the position at which the user faces the operation unit (not shown) that performs various inputs / settings on the image forming apparatus 90 is referred to as the “front side (front side)” of the image forming apparatus 90. " That is, FIG. 1 shows an internal configuration of the image forming apparatus 90 as viewed from the front side. The image forming apparatus shown in FIG. 1 is similarly used in the second embodiment described later. In the drawings, the same parts and the same parts are denoted by the same reference numerals, and duplicate descriptions are omitted.

  In the present embodiment, a color image forming apparatus using an electrophotographic method is used. As shown in FIG. 1, the image forming apparatus 90 is connected to the image forming apparatus main body 100 in order to load the image forming apparatus main body 100 and a large-capacity sheet S and feed the sheet S to the image forming apparatus main body 100. A paper deck 101 is provided. The paper deck 101 constitutes a sheet feeding unit for feeding sheets. The image forming apparatus main body 100 includes an image reading device 80 for reading an image of a document, and a printer unit 95 including an image forming unit 60 for forming an image read by the image reading device 80 on a sheet S. There is. The image forming apparatus 90 includes a control unit (control means) 55 that controls the image reading apparatus 80, the image forming apparatus main body 100, and the like.

  The image reading device 80 includes a scanner unit 81 for reading an image of a document, and an automatic document feeder (hereinafter referred to as an ADF) 82 capable of automatically feeding the document G to the scanner unit 81. The scanner unit 81 has a reading unit 83 used for flow reading or fixed reading of the front surface (first surface) of the document. At a lower portion of the image forming apparatus main body 100, a plurality of sheet feeding units 30 for feeding the sheet S to the image forming unit 60 are provided.

  The image forming unit 60 includes a photosensitive drum 112 on which a toner image is to be formed, a laser scanner unit 111 for irradiating the photosensitive drum 112 with a laser beam, a transfer unit 118 for transferring the toner image onto the sheet S, and a toner image. And a fixing unit 114. A registration roller pair 117 is disposed upstream of the transfer unit 118 in the sheet conveyance path. The image forming unit 60 forms an image forming unit that forms an image on the conveyed sheet S.

  Each sheet feeding unit 30 provided in the printer unit 95 includes a sheet feeding cassette 31 on which the sheets S are stacked, a suction conveyance unit 21 that feeds the sheets S stacked in the sheet feeding cassette 31, and drawing out. The roller pair 23 and the conveyance roller pair 35 are provided. The sheet feeding unit 30 blows air to the end portion of the sheet to float the upper sheet, and the suction conveyance unit 21 adsorbs and conveys the uppermost sheet of the floated sheet by negative pressure, so-called air The paper feed method is adopted.

  On the other hand, the paper deck 101 includes sheet feeding portions 30A, 30B, and 30C in which a plurality of stages (three stages in this embodiment) are arranged in the vertical direction in the deck. The configuration of each of the sheet feeding units 30A, 30B, and 30C is substantially the same, and includes a sheet storage unit 32, a suction conveyance unit 22, and a drawing roller pair 24. Each sheet feeding unit also adopts an air feeding method.

  The paper deck 101 has a deck main body 101a, and in the deck main body 101a, a sheet conveying device 16 for conveying a sheet conveyed from the sheet feeding units 30A, 30B, and 30C is provided. The conveyance device 16 includes a merging guide unit (first conveyance unit) 300, an upper conveyance unit (second conveyance unit) 200, a horizontal pass unit (third conveyance unit) 500, and a lower conveyance unit (fourth conveyance unit) 400, A conveyance path (horizontal direction conveyance path) 12 is provided. The deck main body 101 a constitutes an apparatus main body of the sheet conveying apparatus 16.

  The upper conveyance unit 200 is configured to send the sheet S fed from the sheet storage unit 32 in the upper stage by the suction conveyance unit 22 and the drawing roller pair 24 to the horizontal pass unit 500 downstream. The lower conveyance unit 400 is configured to feed the sheet S fed by the suction conveyance unit 22 and the drawing roller pair 24 from the middle sheet storage unit 32 and the lower sheet storage unit 32 to the downstream horizontal pass unit 500. Ru. In the transport path 12, the sheet is transported when another option deck (not shown) is attached to the right side of the paper deck 101 which is the option deck in FIG. 1 or when a manual paper feed unit is attached.

  The merging guide unit 300 includes a sheet from the curved conveying path 11 of the upper conveying unit 200, a sheet from the linear conveying path 12 communicating with the outside of the paper deck 101, and a curved conveying path of the lower conveying unit 400. Accept the sheet from 13. Then, the merging guide unit 300 feeds the sheet from the transport path (merged transport path) 14 to the transport roller pair 36 of the horizontal pass unit 500. The horizontal pass unit 500 sends the sheet S sent from the lower conveyance unit 400 to the image forming apparatus main body 100 by the conveyance roller pair 25 or the like.

  Next, the image forming operation of the image forming apparatus 90 will be described. When image information of a document fed by the ADF 82 and read by the scanner unit 81 or image information input from a personal computer (PC) (not shown) is input, laser light is transmitted from the laser scanner unit 111 to the photosensitive drum 112 It is irradiated. The photosensitive drum 112 is pre-charged through the charging member 29, and an electrostatic latent image is formed by irradiating the laser beam. Then, the electrostatic latent image is developed by the developing device 113 and is formed as a toner image on the photosensitive drum 112.

  In parallel with the operation of forming a toner image on the photosensitive drum 112, the sheet S for image formation is fed from the sheet feeding units 30, 30A, 30B, and 30C. The fed sheet S is conveyed to the registration roller pair 117. The sheet conveyed to the registration roller pair 117 of the image forming apparatus main body is synchronized with the toner image on the photosensitive drum 112 by the registration roller pair 117, and is sent to the transfer unit 118. The toner image on the photosensitive drum 112 is transferred by the transfer unit 118 to the sheet S sent to the transfer unit 118.

  The sheet S on which the toner image has been transferred is heated and pressed by the fixing unit 114, and the toner image is melted and fixed to the sheet S. According to the user's designation, in the single-sided image forming mode, the sheet S on which the toner image is fixed is discharged onto the discharge tray 59 by the discharge roller pair 46. On the other hand, in the case of the double-sided image forming mode, after the image is fixed on the first surface of the sheet S, the sheet S is re-conveyed toward the registration roller pair 117 via the reverse conveyance path 33, and the operation described above Repeat

[Sheet conveying device]
Next, the sheet conveying device 16 will be described in detail with reference to FIGS. 1 and 2. FIG. 2 is a front view showing the sheet conveying device 16 according to the present embodiment in an enlarged manner.

  As shown in FIGS. 1 and 2, the upper conveying unit 200 of the sheet conveying device 16 joins the sheet S fed from the sheet feeding unit 30A through the drawing roller pair 24 through the curved conveying path 11. There are transport roller pairs 47 and 40 for feeding the guide unit 300. The transport path 11 has an outer guide member 11a located outside the curve and an inner guide member 11b located inside the curve. The transport path 11 is fixed to the deck main body 101 a of the paper deck 101 with the outer guide member 11 a and the inner guide member 11 b facing each other at a predetermined interval.

  The conveyance roller pair 40 disposed on the downstream side of the conveyance path 11 has the drive roller 41 partially projecting from the penetration portion of the inner guide member 11 b and the projection roller partially projecting from the penetration portion of the outer guide member 11 a. And a driven roller 42. The driving roller 41 and the driven roller 42 nip and convey the sheet S by the nip portion N1 located in the conveyance path 11.

  The lower conveyance unit 400 conveys the sheet fed from the middle sheet storage unit 32 and the lower sheet storage unit 32 by the drawing roller pairs 24 to the horizontal pass unit 500 through the curved conveyance path 13. It has 43, 48, 49. The transport path 13 has an outer guide member 13a located outside the curve and an inner guide member 13b located inside the curve, and the outer guide member 13a and the inner guide member 13b have a predetermined interval. Thus, they are fixed to the deck main body 101a in a state of facing each other.

  The conveyance roller pair 43 disposed at the middle portion of the conveyance path 13 is a driven roller 44 having a portion projecting from the penetration portion of the outer guide member 13a and a follower having a portion projecting from the penetration portion of the inner guide member 13b. And a roller 45. The driving roller 44 and the driven roller 45 nip and convey the sheet S by the nip portion N2 located in the conveyance path 13.

  The merging guide unit 300 of the sheet conveying apparatus 16 includes a sheet from the conveying path 11 of the upper conveying unit 200, a sheet fed from the outside such as an optional deck (not shown) via the conveying path 12, and a sheet of the lower conveying unit 400. The sheet from the conveyance path 13 is received. The merging guide unit 300 is configured to feed the sheets from the transport path 14 to the transport roller pair 36 of the horizontal pass unit 500. In the transport path 14, guide gaps (gaps) G1, G2, and G3 respectively corresponding to the transport path 11 of the upper transport unit 200, the transport path 12, and the transport path 13 of the lower transport unit 400 are formed. .

  The horizontal pass unit 500 of the sheet conveyance device 16 conveys the sheet fed through the merging guide unit 300 to the image forming apparatus main body 100 side through the linear conveyance pass 15, and the pair of conveyance rollers 36, 34, 25, 27. have. The transport path 15 has an upper horizontal guide member 15a located on the upper side and a lower horizontal guide member 15b located on the lower side, and the upper horizontal guide member 15a and the lower horizontal guide member 15b have a predetermined interval. It is fixed to the deck main body 101a in a state where it is opened and opposed to each other.

  The conveyance roller pair 36 disposed on the upstream side in the conveyance path 15 protrudes a part from the driven roller 37 having a portion thereof protruding from the penetrating portion of the upper horizontal guide member 15a and a portion of the penetrating portion of the lower horizontal guide member 15b. And a drive roller 38. The sheet S is nipped and transported by the nip portion N3 of the transport roller pair 36 and the respective nip portions of the transport roller pairs 34, 25 and 27.

  In the present embodiment, the upper conveying unit 200 is disposed on the upstream side of the merging guide unit 300 in the sheet conveying direction, and the sheet is transferred via the inner guide member (second guide member) 11b in which the downstream end 11c is opposed to the merging guide 301. The sheet is conveyed to the merging guide unit 300. Further, the merging guide unit 300 transports the sheet conveyed from a plurality of directions (three directions in this embodiment) in one direction while supporting the sheet vertically downward by the merging guide (first guide member) 301. Is configured. Furthermore, the horizontal pass unit 500 is disposed downstream of the merging guide unit 300 in the sheet conveying direction, and the sheet is transferred via the upper horizontal guide member (third guide member) 15a in which the upstream end 15c is opposed to the merging guide 301. It is configured to be transported downstream.

  Next, with reference to FIGS. 2 to 7, the guide portions of the merging guide unit 300 and the like in the present embodiment will be described. 3 is a partially enlarged perspective view of the sheet conveying device 16 according to the present embodiment, and FIG. 4 is a perspective view showing a merging guide 301 and the like in the sheet conveying device 16. As shown in FIG. FIG. 5 is a perspective view showing the merging guide and the like in the sheet conveying apparatus 16 as viewed from an angle different from that in FIG. 4. 6 is a perspective view showing the configuration of FIG. 3 as viewed from the back side, and FIG. 7 is a perspective view showing a configuration in which the horizontal pass unit 500 is fixed to the horizontal pass frame 313.

  As shown in FIG. 2, the sheet S which has passed through the conveying paths 11, 12 and 13 and joined to the conveying path 14 formed by the upper conveying unit 200 and the merging guide unit 300 is a conveying path of the horizontal path unit 500. It is transported to 15. As shown in FIG. 3, the merging guide unit 300 forming the transport path 14 with the upper transport unit 200 is fixed as follows. The merging guide unit 300 is formed by the merging guide 301 and the supporting member 310 extended between the front support column 311 and the rear support column 312 erected at a fixed distance in the deck main body 101a. It is being fixed in the state where it was positioned to 312.

  As shown in FIGS. 4 and 5, the support member 310 is fixed in a state of protruding downward from the bottom surface of the merging guide 301 along the longitudinal direction of the merging guide 301, and the cross section is configured in a substantially T shape as a whole. It is done. The support member 310 is formed longer in the longitudinal direction than the merging guide 301, and fixing holes 310a are formed at both ends thereof.

  As shown in FIGS. 3 to 5, a front guide interval holding member 303 and a rear guide interval holding member 302 are disposed at both ends of the outer side of the sheet conveyance area of the merging guide 301. The front guide interval holding member 303 is raised at the upper part on the receiving surface 303 a formed on the back side in the longitudinal direction of the merging guide 301 and on the downstream side of the sheet conveying direction (the direction of the arrow Co) from the receiving surface 303 a. And a receiving surface 303b formed on the The front guide interval holding member 303 has a receiving surface 303c which is inclined to descend from the receiving surface 303a to the upstream side in the sheet conveying direction, and an inclined surface 303d which is inclined to descend from the receiving surface 303b to the front side. ing. Furthermore, the front guide interval holding member 303 has a circular hole portion 303e formed on the upstream side of the inclined surface 303d in the sheet conveying direction.

  The receiving surface 303a has a thickness sufficient to guarantee a guide gap (gap) G1 between the merging guide 301 and the inner guide member 11b. The receiving surface 303 b has a thickness sufficient to guarantee a guide gap (gap) G 2 between the upper horizontal guide member 15 a and the merging guide 301. Between the receiving surface 303b and the receiving surface 303a, the downstream end 11c of the inner guide member 11b set at a predetermined position is abutted and locked between the receiving surface 303a and the receiving surface 303a. The protrusion 303i is formed.

  Further, the downstream end portion 262a of the horizontal guide 262 abuts between the receiving surface 303a and the receiving surface 303c formed lower than the receiving surface 303a with the inner guide member 11b set at a predetermined position. A stepped portion 303 j to be locked is formed. The receiving surface 303 c supports the lower surface of the downstream end portion 262 a of the horizontal guide 262 in the conveyance path (horizontal direction conveyance path) 12. The receiving surface 303 c has a thickness sufficient to guarantee a guide gap G 3 between the horizontal guide 262 and the merging guide 301. Furthermore, the front guide interval holding member 303 has a positioning projection 303f and a hooking claw portion 303g provided at the lower portion along the longitudinal direction of the merging guide 301.

  The back side guide interval holding member 302 is formed at the upper part so as to be raised on the receiving surface 302 a formed on the near side in the longitudinal direction of the merging guide 301 and on the downstream side of the sheet conveying direction (Co) from the receiving surface 302 a. And a receiving surface 302b. The back side guide interval holding member 302 has a receiving surface 302c which is inclined to descend from the receiving surface 302a in the sheet conveying direction, and an inclined surface 302d which is inclined to descend from the receiving surface 302b. doing. Further, the back side guide interval holding member 302 has a circular hole portion 302h formed on the upstream side of the receiving surface 302b in the sheet conveying direction.

  The receiving surface 302a has a thickness sufficient to guarantee the guide gap G1 between the merging guide 301 and the inner guide member 11b. The receiving surface 302 b has a thickness sufficient to guarantee a guide gap G 2 between the upper horizontal guide member 15 a and the merging guide 301. Between the receiving surface 302b and the receiving surface 302a, which is formed lower than the receiving surface 302b, a step-like lock in which the downstream end 11c of the inner guide member 11b set at a predetermined position abuts and is locked The protrusion 302i is formed.

  Further, the downstream end portion 262a of the horizontal guide 262 abuts between the receiving surface 302a and the receiving surface 302c formed lower than the receiving surface 302a with the inner guide member 11b set at a predetermined position. A stepped portion 302j to be locked is formed. The receiving surface 302 c supports the lower surface of the downstream end 262 a of the horizontal guide 262 in the transport path 12. The receiving surface 302 c has a thickness sufficient to guarantee a guide gap G 3 between the horizontal guide 262 and the merging guide 301. Further, the back side guide interval holding member 302 has hooking claw portions 302e and 302f provided along the sheet conveying direction (Co) at the lower portion, and a positioning projection 302g projected downward. ing.

  Further, as shown in FIGS. 4 and 5, the merging guide 301 is provided with a circular hole 301a and a long hole 301b corresponding to the respective parts of the front guide spacing member 303 at the near end of the longitudinal direction. A circular hole portion 301c is formed. In the merging guide 301, a circular hole 301d, a long hole 301e, a long hole 301f, and a circular hole 301g corresponding to each part of the back side guide interval holding member 302 are formed at the rear end of the longitudinal direction. It is done.

  The circular hole portion 301a corresponds to the positioning projection 303f of the front side guide interval holding member 303, the long hole portion 301b corresponds to the hooking claw portion 303g of the front side guide interval holding member 303, and the circular hole portion 301c is the front side guide It corresponds to the circular hole portion 303 e of the spacing member 303. Also, the circular hole portion 301 d corresponds to the circular hole portion 302 h of the back side guide interval holding member 302, and the long hole portion 301 e corresponds to the hooking claw portion 302 e of the back side guide interval holding member 302. The long hole portion 301 f corresponds to the hooking claw portion 302 f of the back side guide interval holding member 302, and the circular hole portion 301 g corresponds to the positioning projection 302 g of the back side guide interval holding member 302.

  The front guide interval holding member 303 and the rear guide interval holding member 302 are assembled to the merging guide 301 having the above configuration in the following procedure. That is, while the hooking claw portion 303g is inserted from the upper side into the long hole portion 301b of the merging guide 301, the positioning protrusion 303f is inserted from the upper side into the circular hole portion 301a. Then, the front guide spacing member 303 is fixed on the front side of the merging guide 301 by screwing the screw 57 (see FIG. 3) into the circular hole 301c from the circular hole 303e facing in this state.

  Further, while engaging the hooking claws 302e and 302f of the back side guide interval holding member 302 with the long holes 301e and 301f of the merging guide 301, respectively, the positioning projection 302g is inserted into the circular hole 301g from the upper side. Then, the screw 57 (see FIG. 3) is screwed into the circular hole portion 301d from the circular hole portion 302h opposed in this state, so that the back side guide interval holding member 302 is fixed to the back side of the merging guide 301.

  The merging guide 301, the back side guide interval holding member 302 and the front guide interval holding member 303 thus assembled are fixed as follows. That is, as shown in FIG. 3, the support member 310 at the lower part of the merging guide 301 is inserted with the screws 61 from the fixing holes 310 a (FIG. 4 and FIG. 5) at both ends. It fixes by screwing in the formed screw hole (not shown). As a result, the merging guide 301 is fixed so as to extend between the front column 311 and the rear column 312 via the support member 310, and the front guide interval holding member 303 and the rear guide interval holding member are provided at both ends on the joining guide 301. 302 is arranged.

  Here, as shown in FIG. 2 and FIG. 3, the upper conveyance unit 200 is positioned and fixed to the front support post 311 by the front positioning pin 221 and the front insertion convex portion 222. Further, the upper conveyance unit 200 is positioned with respect to the back side post 312 by the back side positioning pin 223, the back side insertion convex portion 224 and the back side receiving portion 225.

  Since the upper transport unit 200 is heavy, the upper transport unit 200 may sink downward in the vertical direction and narrow the guide gap G2 of the transport path 14. So, in this embodiment, the downstream end 11c in the sheet conveyance direction (the direction of the arrow Co) in the inner guide member 11b is supported as follows. That is, the receiving projections 302i and 303i are in contact with the receiving surfaces 302a and 303a of the back side guide interval holding member 302 and the front side guide interval holding member 303 fixed to the front support post 311 and the back support post 312 respectively. Strike. Thereby, the guide gap G2 of the transport path 14 is guaranteed.

  Next, with reference to FIG. 6, the details of the back surface portion of the upper side conveyance unit 200 will be described. FIG. 6 is a perspective view showing details of the back surface portion of the upper side conveyance unit 200. As shown in FIG.

  As shown in FIG. 6, the removable guide unit 260 is fixed to the lower part of the upper conveyance unit 200 by tightening the fixing screw 28. The removable guide unit 260 has an outer guide member 11a (see FIG. 2) and a horizontal guide 262 fixed in contact with the lower end edge of the outer guide member 11a at a predetermined angle. At the center of the back surface of the outer guide member 11a, rotation shafts 42a to which the driven rollers 42 are attached at both ends are supported at both ends.

  In the upper transport unit 200, in addition to the sinking downward (in the direction of the arrow Ve) in the vertical direction due to the weight thereof, there is a possibility that misalignment among components occurs when the removable guide unit 260 is assembled. In the present embodiment, the downstream end portion 262a of the horizontal guide 262 is in contact with the receiving surfaces 302c and 303c of the back side guide interval holding member 302 and the front guide interval holding member 303 while abutting on the step portions 302j and 303j. . Thereby, the guide gap G3 of the transport path 14 is guaranteed (see FIG. 2). Further, the inner guide member 11b supports a rotation shaft 41a to which drive rollers 41 are attached at both ends (see FIG. 3).

  As shown in FIG. 2, in the lower conveyance unit 400, the outer guide member 13a is rotatably supported about a pivot shaft 401a supported by the deck main body 101a (see FIG. 1). When the butting member 402 abuts on the lowermost horizontal guide 262 of the upper conveyance unit 200, the outer guide member for the horizontal guide 262 whose position is properly defined by the back guide distance holding member 302 and the front guide distance holding member 303. The position of 13a is properly determined. As a result, the guide gap (gap) G4 between the horizontal guide 262 and the outer guide member 13a is secured, and the transport path 12 with an appropriate interval is secured. The abutment members 402 are provided in the front and back directions in FIG. 2 so as not to hinder the sheet conveyance in the conveyance path 12. The appropriate spacing means the spacing (dimension) set in the design to guide the sheet so as not to generate a sheet jam or the like.

  In the lower conveyance unit 400, the inner guide member 13b is rotatably supported about a pivot shaft 404 supported by the deck body 101a. Abutment member 403 abuts on the outer side guide member 13 a located on the outer side of the curve of the conveyance path 13 in the lower side conveyance unit 400 and the inner guide member 13 b located on the inner side of the curvature outside the sheet conveyance area. As a result, the guide gap (gap) G5 between the outer guide member 13a and the inner guide member 13b is secured, and the transport path 13 with an appropriate interval is secured. The abutment members 403 are provided in the front and back directions in FIG. 2 so as not to interfere with sheet conveyance in the conveyance path 13.

  Next, with reference to FIG. 7, a configuration in which the horizontal pass unit 500 is mounted and fixed to the horizontal pass frame 313 will be described. FIG. 7 is a perspective view showing a configuration in which the horizontal pass unit 500 is fixed to the horizontal pass frame 313. In FIG. 7, the front and back directions in FIG. 2 are shown in a slightly oblique state.

  As shown in FIG. 7, the horizontal path frame 313 is fixed to the deck main body (apparatus main body) 101a (see FIG. 1) via the back side post 312, the front side post 311 and the like. The horizontal pass frame 313 is located in the horizontal direction (direction of arrow Ho in FIG. 7) and at the back side of the horizontal portion 313 d and in the vertical direction (direction of arrow Ve in FIG. 7). And a vertical portion 313e. On the front side of the horizontal portion 313 d in FIG. 7, front positioning circular holes 313 b and 313 a are provided at the left and right ends, respectively. A rear positioning round hole 313 c and a rear positioning long hole (not shown) are provided on the lower side of the vertical section 313 e in the vicinity of the rear column 312 in FIG. 7.

  A rail portion 313 f is provided on the side of the front support post 311 and the back support post 312 in the horizontal path frame 313, and a rail portion 313 g is provided on the side of the horizontal path frame 313 opposite to the support posts 311 and 312. ing. The horizontal pass unit 500 has supported portions 500a slidably supported by the rail portions 313f and supported portions 500b slidably supported by the rail portions 313g at both end portions in the horizontal direction. The horizontal pass unit 500 has a hand front surface 500c on the near side of the supported portions 500a and 500b in FIG. 7 and a back side surface 500d on the back side of the supported portions 500a and 500b in FIG.

  In the hand front surface portion 500c, the positioning pin 503 engaged with the front positioning circular hole portion 313a and the front positioning circular hole portion 313b are engaged when the horizontal pass unit 500 is pressed into and attached to the horizontal path frame 313 Positioning pins 504 are provided. When the horizontal pass unit 500 is pushed into and attached to the horizontal pass frame 313 in the back side surface portion 500d, the positioning pin 505 engaged with the back side positioning circular hole portion 313c and the back side positioning circle (not shown) A positioning pin 506 is provided for engaging the hole.

  The horizontal pass unit 500 is slidably supported relative to the horizontal pass frame 313 by a slide mechanism 58 configured of the rail portion 313f, the supported portion 500a, the rail portion 313g, and the supported portion 500b. Horizontal pass unit 500 is positioned and mounted on horizontal pass frame 313 by positioning pins 503, 504, 505, and 506 engaging with the above-mentioned positioning circular holes 313a, 313b, 313c, etc. facing each other. Ru. However, since the weight of the horizontal pass unit 500 is large, the four positioning pins 503 to 506 are deformed by the weight of the horizontal pass unit 500 and the horizontal pass frame 313, and the entire horizontal pass unit is downward in the vertical direction (arrow Ve direction). May sink into the In that case, the guide gap between the guides in the corresponding transport path, for example, the guide gap G2 between the merging guide 301 of the merging guide unit 300 and the upper horizontal guide member 15a of the transport path 15 becomes narrower than necessary. Jams are more likely to occur.

  Therefore, in the present embodiment, as shown in FIGS. 3 to 5, in the front and back direction (direction of arrow D1 in FIG. 3) of the long merging guide 301, the back side guide interval holding member 302 described above is disposed on the back side. The above-mentioned front side guide interval holding member 303 is disposed on the near side (front side). Therefore, when the horizontal pass unit 500 is slid from the state shown in FIG. 7 to the back side (right direction) in the figure, the following occurs. That is, the upstream end portion 15c of the upper horizontal guide member 15a (see FIG. 2) rides on the receiving surface 303b while being guided by the inclined surface 303d of the front guide interval holding member 303 along with the slide movement. Further, the upstream end 15 c rides on the receiving surface 302 b while being guided by the inclined surface 302 d of the back side guide interval holding member 302.

  Then, the upstream end portion 15c of the upper horizontal guide member 15a is held by the receiving surfaces 303b and 303b at the lower side, so that the occurrence of a shift or a step between the transport path 14 and the transport path 15 can be prevented. . As a result, on the downstream side of the transport path 14, the transport path 15 is properly configured by the upper horizontal guide member 15a and the lower horizontal guide member 15b which is supported to be openable and closable.

  Here, the sheet conveying device 66 according to the comparative example will be described with reference to FIG. FIG. 10 is a schematic view showing a sheet conveying device 66 according to the present comparative example. In the present comparative example, the same members as those of the first embodiment are denoted by the same reference numerals, and the descriptions of the same members as those of the first embodiment are omitted.

  That is, in the present comparative example, when bookbinding is performed, for example, it is necessary to convey various sheets having different sizes and thicknesses from the sheet storage unit 32 (see FIG. 1). It has a path configuration that merges from three directions. Here, while the merging guide unit 300 is a relatively lightweight unit attached to the deck main body 101a (see FIG. 1), the upper conveyance unit 200 and the horizontal pass unit 500 are large-sized, heavy-weight units. . Therefore, when both units 200 and 500 are attached to the deck main body 101a, there is a high possibility that distortion of the unit and distortion of the deck main body 101a may occur due to the weight of the units. Therefore, the guide gap G2 between the upstream end 15c of the conveyance path 15 and the merging guide 301 of the conveyance path 14 is narrowed, and further, a step is generated discontinuously between the conveyance path 14 and the conveyance path 15, etc. Inconvenient. As a result, when a sheet such as thick paper is transported, the resistance received from the inner guide member 11b at the upper portion of the transport path 14 and the upper horizontal guide member 15a at the upper portion of the transport path 15 increases, and the risk of jamming increases. .

  With respect to such a comparative example, in the present embodiment, by arranging the back side guide interval holding member 302 and the front guide interval holding member 303 at both ends of the joining guide 301, each guide of the conveying paths 11 to 15 to join The guide gap by is guaranteed. As a result, when a sheet such as thick paper is conveyed, the occurrence of jamming is reduced.

  In the above embodiment, the back side guide interval holding member 302 and the front guide interval holding member 303 are interposed between the merging guide 301, the downstream end 11c and the upstream end 15c. As a result, the guide gap G1 between the merging guide 301 and the downstream end 11c and the guide gap G2 between the merging guide 301 and the upper horizontal guide member 15a have an appropriate distance for guiding the sheet without causing a jam or the like. It becomes possible to set and hold.

  Further, in the present embodiment, the locking projections 302i and 303i of both the guide interval holding members 302 and 303 butt the downstream end 11c of the inner guide member 11b in the upper conveyance unit 200 in a bending direction due to gravity and lock it. Do. The receiving surfaces 302 b and 303 b of both the guide interval holding members 302 and 303 abut the upstream end 15 c of the upper horizontal guide member 15 a in the horizontal pass unit 500 and support it from below in the vertical direction. Therefore, the downstream end 11c of both widthwise end portions of the inner guide member 11b orthogonal to the sheet conveying direction and the upstream end 15c of both widthwise end portions of the upper horizontal guide member 15a It can be held properly. Thus, the corresponding guide intervals can be set and held at appropriate intervals.

  In the present embodiment, both guide interval holding members 302 and 303 are fixed to both ends in the width direction of the merging guide 301, respectively. As a result, both guide interval holding members 302 and 303 can be interposed between the merging guide 301, the downstream end 11c and the upstream end 15c at both ends of the merging guide 301. Therefore, the guide gap G1 between the merging guide 301 and the downstream end 11c and the guide gap G2 between the merging guide 301 and the upper horizontal guide member 15a can be maintained at appropriate intervals.

  Further, in the present embodiment, the merging guide unit 300, the upper conveyance unit 200, and the horizontal pass unit 500 are supported by the deck main body 101a. The front support (first support) 311 and the back support (second support) supported by the deck body 101 a and disposed at both ends in the width direction between the upper conveyance unit 200 and the horizontal pass unit 500. 312 are arranged. Further, a merging guide 301 in which both guide interval holding members 302 and 303 are fixed to both ends in the width direction is supported so as to extend between the front support column 311 and the rear support column 312. Thus, by attaching the merging guide 301 to the columns 311 and 312 supported by the deck main body 101a and disposed at both ends in the width direction, both guide interval holding members 302 between the respective guides at both ends of the merging guide 301. , 303 can be interposed at an appropriate position.

  In the present embodiment, the lower conveyance unit 400 for conveying the sheet to the merging guide unit 300 is disposed vertically below the upper conveyance unit 200 and upstream of the merging guide unit 300 in the sheet conveyance direction. A conveyance path (horizontal direction conveyance path) 12 for conveying the sheet in the horizontal direction to the merging guide unit 300 is disposed between the upper conveyance unit 200 and the lower conveyance unit 400. Further, both the guide spacing members 302 and 303 have receiving surfaces 302 c and 303 c for supporting the downstream end 262 a of the horizontal guide 262 in the transport path 12. Thus, the downstream end 262a of the horizontal guide 262 of the conveyance path 12 can be supported at an appropriate position by the receiving surfaces 302c and 303c.

  Further, in the present embodiment, the upper conveyance unit 200, the merging guide unit 300, and the horizontal pass unit 500 form a curved conveyance path 39 that descends from the upper side in the vertical direction to the downstream side in the sheet conveyance direction. The inner guide member 11 b and the upper horizontal guide member 15 a are positioned inside the curve of the curved conveying path 39, and the merging guide 301 is positioned outside the curve of the curved conveying path 39. Therefore, the curved guide path is maintained while maintaining an appropriate guide interval by the inner guide member 11b and the upper horizontal guide member 15a located inside the curve, and while maintaining an appropriate guide interval by the merging guide 301 located outside the curve. 39 can be configured.

Second Embodiment
Next, a sheet conveying apparatus 16 according to a second embodiment of the present invention will be described with reference to FIGS. 8 (a), (b) and FIG. In the present embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and descriptions of components having the same configuration and function are omitted.

  In the first embodiment, the downstream end 11c is abutted against the locking projections 302i and 303i of both holding members 302 and 303 and locked, and the upstream end 15c is abutted on the receiving surfaces 302b and 303b to be vertical. The guide gaps G1 and G2 were guaranteed by supporting from the lower direction. On the other hand, in the second embodiment, the guide gaps G1 and G2 are guaranteed by different configurations.

  In order to make it easier to feed a sheet such as a thick sheet, it is effective to make the guide gaps G1 and G2 in the transport path 14 as large as possible, as shown in FIG. 8A. However, if the guide gaps G1 and G2 are too large, jamming is likely to occur when the leading edge of the sheet S such as thin paper being conveyed is curled. Therefore, in the present embodiment, by setting the guide gaps G1 and G2 as large as possible but effectively preventing the guide gaps G1 and G2 from becoming too large, they are set and held at appropriate intervals.

  In the present embodiment, as shown in FIG. 8B and FIG. 9, the back side guide interval holding members 304 and the front guide interval holding members 305 are disposed at both ends of the merging guide 301. The holding members 304 and 305 are interposed between the merging guide 301 and the downstream end 11 c of the inner guide member 11 b and between the merging guide 301 and the upstream end 15 c of the upper horizontal guide member 15 a. As a result, the distance between the merging guide 301 and the downstream end 11c of the inner guide member 11b and the distance between the merging guide 301 and the upper horizontal guide member 15a are set. Holding members 304 and 305 are interposed between the merging guide 301, the downstream end 11c and the upstream end 15c, and the guide gap G1 of the merging guide 301 and the downstream end 11c, and the guide gap G2 of the merging guide 301 and the upper horizontal guide member 15a. Set and hold at appropriate intervals. Also in the present embodiment, the back side guide interval holding member 304 and the front guide interval holding member 305 are fixed to the both ends of the merging guide 301 in the same manner as in the first embodiment described above.

  The front guide interval holding member 305 is inclined at an upper portion thereof so as to descend from the receiving surface 305 e formed in the longitudinal direction of the merging guide 301 and the far side 305 b of the receiving surface 305 e to the upstream side in the sheet conveying direction. 305a and 305g. The front guide interval holding member 305 is an inclined surface 305 d inclined so as to descend from the receiving surface 305 e to the front side, and a circular hole (not shown) formed on the upstream side of the inclined surface 305 d And. Further, the front guide interval holding member 305 has an inclined surface 305 d which is inclined so as to descend from the receiving surface 305 e to the front side. The receiving surface 305 g supports the downstream end 262 a of the horizontal guide 262 in the conveyance path (horizontal direction conveyance path) 12.

  The front guide interval holding member 305 has a first locking projection 305 c which abuts the downstream end 11 c of the inner guide member 11 b in the upper conveyance unit 200 in a bending direction due to gravity and holds it in the vertical direction. Further, the front guide interval holding member 305 has a second locking projection 305 f which abuts on the upstream end 15 c of the upper horizontal guide member 15 a in the horizontal path unit 500 and holds and locks in the vertical direction. The second locking projection 305 f receives and positions the upstream end 15 c in a gap between the second locking projection 305 f and the opposing receiving surface 305 e.

  The back side guide interval holding member 304 is inclined at an upper portion so as to descend downward from the receiving surface 304e formed in the longitudinal direction of the merging guide 301 and the front side 304b of the receiving surface 304e in the sheet conveying direction. And faces 304a and 304g. In addition, the back side guide interval holding member 304 is formed on the upstream side of the sheet conveyance direction of the inclined surface 304d and the inclined surface 304d which are inclined so as to descend from the receiving surface 304e to the front side. And a circular hole (not shown). Furthermore, the back side guide interval holding member 304 has an inclined surface 304 d which is inclined so as to descend from the receiving surface 304 e to the front side. The receiving surface 304 g supports the downstream end 262 a of the horizontal guide 262 in the transport path 12.

  The back side guide interval holding member 304 has a first locking projection 304 c which abuts the downstream end 11 c of the inner guide member 11 b in a bending direction due to gravity and holds the downstream end 11 c in the vertical direction. Further, the back side guide interval holding member 304 has a second locking projection 304 f which abuts on the upstream end 15 c of the upper horizontal guide member 15 a and holds and locks in the vertical direction. The second locking projection 304 f receives and positions the upstream end 15 c in a gap between the second locking projection 304 f and the opposing receiving surface 304 e.

  When sliding the horizontal path unit 500 (see FIG. 7) to the back side in FIG. 7 with the above holding members 304 and 305, the upstream end portion 15c moves along with the sliding movement and moves the front guide interval holding member 305. On the receiving surface 305e while being guided by the inclined surface 305d. Further, the upstream end portion 15 c rides on the receiving surface 304 e while being guided by the inclined surface 304 d of the back side guide interval holding member 304.

  In the above embodiment, both the holding members 304 and 305 hold the downstream end portion 11c of the inner guide member 11b in the upper conveyance unit 200 in the bending direction due to gravity, and hold and hold the downstream end portion 11c in the vertical direction. It has the stop protrusion 304c, 305c. Further, the guide interval holding members 304 and 305 abut on the upstream end 15c of the upper horizontal guide member 15a in the horizontal pass unit 500 and hold the second locking projections 304f and 305f for clamping and holding in the vertical direction. Have. Therefore, the holding members 304 and 305 can properly hold the downstream end 11c of both widthwise end portions of the inner guide member 11b and the upstream end 15c of both widthwise end portions of the upper horizontal guide member 15a. It will be possible. This makes it possible to set and hold the corresponding guide intervals at appropriate intervals.

  As described above, even if deflection due to gravity occurs, the guide interval holding members 304 and 305 sandwich and position the downstream end 11c of the inner guide member 11b and the upstream end 15c of the upper horizontal guide member 15a. it can. This makes it possible to guarantee the guide gaps G1 and G2 with the merging guide 301 with high accuracy. Therefore, the guide gaps G1 to G3 between the guides in the transport path 14 can be secured at appropriate intervals, and a sheet such as thick paper is transported without generating a discontinuous step between the transport path 14 and the transport path 15. Can reduce the occurrence of jams (paper jams).

  Further, since the guide spacing member 304, 305 has receiving surfaces 304g, 305g for supporting the downstream end 262a of the horizontal guide 262 in the transport path 12, the downstream end 262a of the horizontal guide 262 in the transport path 12 is appropriate. Support it. Furthermore, the guide gaps G1 and G2 can be regulated so as to be as large as possible but not too large, and can be maintained at a predetermined interval. For this reason, even when the sheet S such as thin paper is conveyed and its leading end is curled, it is possible to stabilize the conveyance performance for the sheet S such as thin paper without causing a jam.

  In the first and second embodiments described above, the back side guide interval holding members 302 and 304 and the front guide interval holding members 303 and 305 are fixed to the merging guide 301 side, but the invention is not limited to this and the inner guide member 11 b Alternatively, it may be fixed to the upper horizontal guide member 15a.

  Although the first and second embodiments have been described using the electrophotographic image forming apparatus 90, instead of this, for example, an inkjet that forms an image on a sheet by discharging an ink liquid from a nozzle It is also possible to use a system image forming apparatus. In that case, the image forming unit is configured by an image forming unit that discharges the ink liquid onto the sheet to form an image.

  11b ... inner guide member (second guide member) / 11c ... downstream end / 12 ... conveyance path (horizontal direction conveyance path) / 15a ... upper horizontal guide member (third guide member) / 15c ... upstream end / 16 ... Sheet conveying device / 39: Curved conveying path / 60: Image forming unit (image forming means) / 90: Image forming device / 101a: Deck main body (device main body) / 200: Upper side conveying unit (second conveying unit) / 262 ... Horizontal guide / 262a ... downstream end / 300 ... merging guide unit (first conveyance unit) / 301 ... merging guide (first guide member) / 302, 303 ... back side guide interval holding member, front guide interval holding member (guide Space maintaining member) / 302 b, 303 b ... Receiving surface / 302 c, 303 c ... Receiving surface / 302 i, 303 i ... Locking projection / 304, 305 ... Back side guide distance maintaining Members, front guide spacing holding members (guide spacing holding members) / 304c, 305c ... first locking projections / 304f, 305f ... second locking projections / 304g, 305g ... receiving surface / 311 ... front post (first Post) / 312 ... Back side post (second post) / 400 ... Lower transport unit (fourth transport unit) / 500 ... Horizontal pass unit (third transport unit) / Co ... Sheet transport direction / D1 ... Width direction / G1, G2 ... Guide gap (distance) / Ho ... Horizontal direction / S ... Sheet / Ve ... Vertical direction

Claims (8)

A first conveyance unit that supports and guides sheets conveyed from a plurality of directions from below by a first guide member;
A second guide member is disposed upstream of the first conveyance unit in the sheet conveyance direction, and has a second guide member disposed with the downstream end facing the first guide member, and guides the sheet toward the first conveyance unit. A second transport unit,
The third guide member is disposed downstream of the first conveyance unit in the sheet conveyance direction, and has the third guide member disposed with the upstream end facing the first guide member, and the sheet guided by the first conveyance unit is A third conveyance unit that guides downstream;
The first guide member and the second guide are interposed between the downstream end of the first guide member and the second guide member and between the upstream end of the first guide member and the third guide member. A guide interval holding member for setting the distance between the downstream end of the member and the distance between the first guide member and the third guide member;
Sheet conveying apparatus characterized in that. The guide interval holding members are respectively fixed to the outside of a sheet conveyance area in a width direction orthogonal to the sheet conveyance direction of the first guide member.
The sheet conveying apparatus according to claim 1, The first transport unit, the second transport unit, and the third transport unit are supported by the apparatus main body, respectively.
Between the second transport unit and the third transport unit, there are provided a first support and a second support supported by the apparatus main body and disposed at both ends in the width direction orthogonal to the sheet transport direction,
The first guide members, each having the guide spacing holding members fixed to both ends in the width direction, are supported in a state of being extended between the first support and the second support.
The sheet conveying apparatus according to claim 1 or 2, wherein The guide interval holding member is
A locking projection which abuts and locks the downstream end of the second guide member in the second transport unit in a bending direction by gravity;
A receiving surface which abuts the upstream end of the third guide member in the third conveyance unit and supports the upstream end from below;
The sheet conveying apparatus according to any one of claims 1 to 3, wherein The guide interval holding member is
A first locking projection which abuts on the downstream end of the second guide member in the second conveyance unit in a bending direction due to gravity and sandwiches and holds in a vertical direction;
And a second locking projection that abuts on the upstream end of the third guide member in the third transport unit and sandwiches and locks in the vertical direction;
The sheet conveying apparatus according to any one of claims 1 to 3, wherein A fourth conveyance unit which is disposed below the second conveyance unit in the vertical direction and upstream of the first conveyance unit in the sheet conveyance direction, and guides a sheet to the first conveyance unit;
And a horizontal conveyance path disposed between the second conveyance unit and the fourth conveyance unit and guiding the sheet in the horizontal direction to the first conveyance unit.
The guide spacing member has a receiving surface for supporting the downstream end of the horizontal guide in the horizontal conveyance path.
The sheet conveying apparatus according to claim 4 or 5, wherein The second conveyance unit, the first conveyance unit, and the third conveyance unit form a curved conveyance path that descends from the upper side in the vertical direction to the downstream side in the sheet conveyance direction.
The second guide member and the third guide member are positioned inside the curvature of the curved transport path, and the first guide member is positioned outside the curvature of the curved transport path.
The sheet conveying apparatus according to any one of claims 1 to 6, wherein A sheet conveying apparatus according to any one of claims 1 to 7.
An image forming unit that forms an image on a sheet to be conveyed;
An image forming apparatus characterized by

Images