Patent Publication Number: US-11662683-B2

Title: Sheet processing apparatus and image forming system

Description:
This is a continuation of U.S. patent application Ser. No. 16/890,085, filed Jun. 2, 2020. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a sheet processing apparatus which processes a sheet and an image forming system which forms an image on the sheet. 
     Description of the Related Art 
     As an option for an image forming apparatus, for example, an electrophotographic type composite machine, a sheet processing apparatus is used to perform a binding process and sorting process to a sheet with an image formed by the image forming apparatus. Japanese Patent Laid-Open No. 2011-207560 describes the sheet processing apparatus which aligns a sheet bundle stacked on a compiling purpose stacking portion by a side guide and a tamper and thereafter staples the aligned sheet bundled by a stapler or a needleless binding apparatus. The stapler and the needleless binding apparatus are movably supported by a stapler rail and a needleless binding apparatus rail, respectively, and are able to move to an edge and a corner portion of the sheet bundle. 
     Japanese Patent Laid-Open No. 2015-63387 describes a postprocessing apparatus which includes a stacker unit to stack the sheet bundle, performs the binding process of binding the sheet bundle by a saddle stitching stapler, and is able to perform a folding process to the sheet bundle by a folding roller unit. In the stacker unit, a front edge regulation member is provided to regulate a position of a downstream edge portion of the sheet bundle in a sheet conveyance direction, and the front edge regulation member is supported movable in the sheet conveyance direction depending on a size of the sheet. Further, a position of the sheet bundle stacked on the stacking unit in a width direction is aligned by a sheet side edge aligning member. 
     However, since it is unable to dispose the side guide and the tamper described in Japanese Patent Laid-Open No. 2011-207560 within a moving range of the stapler or the needleless binding apparatus, there were cases where alignment of the sheet was not performed well. Further, since it is also unable to dispose the sheet side edge aligning member described in Japanese Patent Laid-Open No. 2015-63387 within a moving range of the front edge regulation member, there were cases where the alignment of the sheet was not performed well. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, a sheet processing apparatus includes a conveyance unit configured to convey a sheet, a stacking portion on which the sheet conveyed by the conveyance unit is stacked, a first regulation member configured to regulate a position of an edge portion, in a conveyance direction, of the sheet stacked on the stacking portion, a second regulation member configured to regulate a position of an edge portion, in a width direction orthogonal to the conveyance direction, of the sheet stacked on the stacking portion, a binding unit supported movably in the conveyance direction and configured to perform a binding process of binding the sheet stacked on the stacking portion, and a moving unit configured to move the second regulation member in the conveyance direction accompanied with a movement, in the conveyance direction, of the binding unit. 
     According to a second aspect of the present invention, a sheet processing apparatus includes a conveyance unit configured to convey a sheet, a stacking portion on which the sheet conveyed by the conveyance unit is stacked, a first regulation member configured to regulate a position of an edge portion, in a conveyance direction, of the sheet stacked on the stacking portion, a second regulation member configured to regulate a position of an edge portion, in a width direction orthogonal to the conveyance direction, of the sheet stacked on the stacking portion, and a binding unit supported movably in the conveyance direction and configured to perform a binding process of binding the sheet stacked on the stacking portion, wherein the binding unit is disposed not to overlap with the second regulation member when viewed in the conveyance direction. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram showing a general configuration of an image forming system according to a first embodiment of the present invention. 
         FIG.  2    is a perspective view showing a binding process unit. 
         FIG.  3 A  is a side view of the binding process unit to illustrate a movement of the binding process unit. 
         FIG.  3 B  is a front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  3 C  is the side view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  3 D  is the front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  4 A  is the side view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  4 B  is the front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  4 C  is the side view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  4 D  is the front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  5 A  is the side view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  5 B  is the front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  5 C  is the side view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  5 D  is the front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  6 A  is the side view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  6 B  is the front view of the binding process unit to illustrate the movement of the binding process unit. 
         FIG.  7 A  is a front view of a binding process unit according to a comparative example. 
         FIG.  7 B  is the front view of the binding process unit showing a rotating movement of the sheet. 
         FIG.  8 A  is a side view of a moving unit according to the first embodiment. 
         FIG.  8 B  is a side view of the moving unit with a driving motor driving. 
         FIG.  9 A  is the front view of the binding process unit showing a position of a crosswise alignment reference plate in alignment of a legal-size sheet. 
         FIG.  9 B  is the front view of the biding process unit showing the position of the crosswise alignment reference plate in the alignment of an A5-size sheet. 
         FIG.  10 A  is a front view of a binding process unit according to a second embodiment showing a position of a movable crosswise alignment reference member in the alignment of the legal-size sheet. 
         FIG.  10 B  is the front view of the binding process unit showing the position of the movable crosswise alignment reference member in the alignment of the A5-size sheet. 
         FIG.  11 A  is a front view of a binding process unit according to a third embodiment showing movable crosswise alignment reference members. 
         FIG.  11 B  is the front view of the binding process unit showing the movable crosswise alignment reference members. 
         FIG.  12 A  is a front view of a binding process unit according to a fourth embodiment showing a position of a stapler in an alignment movement. 
         FIG.  12 B  is the front view of the binding process unit showing the position of the stapler at completion of a binding process. 
         FIG.  13    is a perspective view showing a movable crosswise alignment reference member and a moving unit. 
         FIG.  14    is a perspective view showing the stapler, the movable crosswise alignment reference member and the moving unit. 
         FIG.  15    is a schematic-view of the stapler and the movable crosswise alignment reference member. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. 
     First Embodiment 
     General Configuration 
     An image forming system  15  according to a first embodiment is configured with an image forming apparatus  1 , an image reading apparatus  2 , a document feeding apparatus  3 , and a postprocessing apparatus  4 . The image forming system  15  forms an image on a sheet, which is a recording material, and outputs the sheet after performing a processing of the sheet by the postprocessing apparatus  4 , if required. Hereinafter, a movement of each apparatus will be described simply, and thereafter the postprocessing apparatus  4  will be described in detail. 
     The document feeding apparatus  3  transports a document placed on a document tray  18  to image reading units  16  and  19 . Each of the image reading units  16  and  19  is an image sensor to read image information from a surface of the document, and image information is read from both sides by once conveyed the document. The document having been read of the image information is discharged to a document discharge portion  20 . Further, by reciprocally moving the image reading unit  16  by a driving device  17 , the image reading apparatus  2  is able to read the image information from a stationary document put on a platen glass (including a document for which the document feeding apparatus  3  is unusable, such as a booklet document). 
     The image forming apparatus  1  is an electrophotographic apparatus furnished with an image forming unit  1 B of a direct transfer system. The image forming unit  1 B includes a cartridge  8  having a photosensitive drum  9 , and a laser scanner unit  15  disposed above the cartridge  8 . To perform an image formation, a surface of the rotating photosensitive drum  9  is charged, and the laser scanner unit  15  bears an electrostatic latent image on the surface of the photosensitive drum  9  by exposing the photosensitive drum  9  based on the image information. The electrostatic latent image born on the photosensitive drum  9  is developed with a charged toner particle to a toner image, and the toner image is transferred to a transfer portion at which the photosensitive drum  9  and a transfer roller  10  are facing each other. A controller of the image forming apparatus  1  performs an image forming processing of the image forming unit  1 B based on the image information read by the image reading units  16  and  19  or image information received from an external computer via a network. 
     The image forming apparatus  1  includes a plurality of feeding units  6  which feed the sheet, the recording material, one by one at a predetermined interval. After corrected a sheet skew at a pair of registration rollers  7 , the sheet fed from the plurality of the feeding units  6  is conveyed to the transfer portion, and transferred by the toner image born on the photosensitive drum  9  at the transfer portion. A fixing unit  11  is disposed downstream of the transfer portion in a sheet conveyance direction. The fixing unit  11  includes a pair of rotary members to convey the sheet in a sandwiched manner and a heating member, such as a halogen lamp, to heat the toner image, and performs a development process of an image by heating and pressing the toner image on the sheet. 
     In a case where the sheet having been formed of the image is discharged outside the image forming apparatus  1 , the sheet which has passed the fixing unit  11  is conveyed to the postprocessing apparatus  4  via a horizontal conveyance portion  14 . In a case of the sheet on which the image of a first surface of double-sided printing has been formed, the sheet which has passed the fixing unit  11  is delivered to a pair of reverse conveyance rollers  12 , and is conveyed in a switchback conveyance manner by the pair of the reverse conveyance rollers  12  to the pair of the registration rollers  7  again via a reconveyance portion  13 . Then, by passing the transfer portion and fixing unit  11  again, the sheet is formed of the image on a second surface of the sheet, and is conveyed to the postprocessing apparatus  4  via the horizontal conveyance portion  14 . 
     The image forming unit  1 B described above is an example of the image forming unit, an electrophotographic unit of an intermediate transfer system which transfers the toner image born on a photosensitive member to the sheet via an intermediate transfer member is also acceptable. Further, it is also acceptable to use an ink jet system and an offset printing system as the image forming unit. 
     Postprocessing Apparatus 
     The postprocessing apparatus  4  includes a binding process unit  4 A to perform a binding process to the sheet, and discharges a sheet bundle after performing the binding process to the sheet received from the image forming apparatus  1 . Further, the postprocessing apparatus  4  is capable of discharging the sheet received from the image forming apparatus  1  without performing the binding process. 
     The postprocessing apparatus  4  includes, a receiving path  81 , an inner discharge path  82 , a first discharge path  83 , and a second discharge path  84 , as conveyance paths on which the sheet is conveyed, and includes an upper sheet discharge tray  25  and a lower sheet discharge tray  37 , as discharge destinations to which the sheet is discharged. The receiving path  81 , as a first conveyance path, is the conveyance path on which the sheet received from the image forming apparatus  1  is conveyed, and the inner discharge path  82 , as a second conveyance path, is the conveyance path which extends below the receiving path  81  and guides the sheet toward the binding process unit  4 A. The first discharge path  83  is the conveyance path to discharge the sheet to the upper sheet discharge tray  25 , and the second discharge path  84 , as a third conveyance path, is the conveyance path extending along a sheet discharge direction CD, described later, and guiding the sheet toward the lower sheet discharge tray  37 . 
     The sheet discharged from the horizontal conveyance portion  14  of the image forming apparatus  1  is received by a pair of inlet rollers  21 , and conveyed to a pair of pre-reverse conveyance rollers  22  passing through the receiving path  81 . An inlet sensor  27  detects the sheet at a detection position disposed between the pair of the inlet rollers  21  and the pair of the pre-reverse conveyance rollers  22 . The pair of the pre-reverse conveyance rollers  22  conveys the sheet received from the pair of the inlet rollers  21  toward the first discharge path  83 . 
     To be noted, at a predetermined timing after detection of a passage of a trailing edge of the sheet by the inlet sensor  27 , the pair of the pre-reverse conveyance rollers  22  accelerate a sheet conveyance speed to faster than the sheet conveyance speed at the horizontal conveyance portion  14 . On the other hand, it is acceptable to set the sheet conveyance speed of the pair of the inlet rollers  21  larger than the sheet conveyance speed at the horizontal conveyance portion  14  and accelerate the sheet conveyance speed at the pair of the inlet rollers  21  which is disposed upstream of the pair of the pre-reverse conveyance rollers  22 . In this case, it is preferred to provide a one way clutch(es) between a plurality of conveyance rollers at the horizontal conveyance portion  14  and a driving motor(s) of the plurality of the conveyance rollers, and configure the plurality of the conveyance rollers to rotate idly in a case where the sheet is pulled by the pair of the inlet rollers  21 . 
     In a case where the sheet is discharged to the upper sheet discharge tray  25 , a pair of reverse conveyance rollers  24  discharge the sheet received from the pair of the pre-reverse conveyance rollers  22  to the upper sheet discharge tray  25 . In this case, the pair of the reverse conveyance rollers  24  reduce the sheet conveyance speed to a predetermined discharge speed in a predetermined timing after the trailing edge of the sheet has passed the pair of the pre-reverse conveyance rollers  22 . 
     In a case where the sheet is discharged to the lower sheet discharge tray  37 , the pair of the reverse conveyance rollers  24 , as a reverse portion, performs switchback-conveyance of inverting the sheet received from the pair of the pre-reverse conveyance rollers  22  to the inner discharge path  82 . A check valve  23  is arranged at a branch portion of the receiving path  81  and the inner discharge path  82  from the first discharge path  83 . Incidentally, the branch portion is disposed upstream of the pair of the reverse conveyance rollers  24  in a sheet discharge direction of the pair of the reverse conveyance rollers  24 . The check valve  23  has a function to regulate the sheet conveyed by the pair of the reverse conveyance rollers  24  in the switchback conveyance manner not to flow backward to the receiving path  81 . 
     A pair of inner discharge rollers  26 , a pair of intermediate conveyance rollers  28 , and a pair of kick-out rollers  29  disposed on the inner discharge path  82  successively convey the sheet received from the pair of the reverse conveyance rollers  24  to a binding process unit  4 A. A preceding intermediate stacker sensor  38  detects the sheet between the pair of the intermediate conveyance rollers  28  and the pair of the kick-out rollers  29 . Regarding the inlet sensor  27  and the preceding intermediate stacker sensor  38 , it is acceptable to use an optical sensor which detects presence and absence of the sheet at the detection position using light. 
     The binding process unit  4 A includes a stapler  51  described later (refer to  FIG.  2   ), and, having aligned a plurality of the sheets received from the inner discharge path  82 , binds a predetermined position of a sheet bundle by the stapler  51 . Detail configurations and movements of the binding process unit  4 A will be described later. The sheet bundle bound by the binding process unit  4 A is delivered to a pair of bundle discharge rollers  36  via the second discharge path  84 , and discharged outside the apparatus by the pair of the bundle discharge rollers  36 , as a discharge unit, and stacked on the lower sheet discharge tray  37 . 
     Both of the upper sheet discharge tray  25  and the lower sheet discharge tray  37  are capable of ascending and descending with respect to a casing of the postprocessing apparatus  4 . The postprocessing apparatus  4  includes sheet surface detection sensors to detect a position of an uppermost sheet (stacking height of the sheet) on the upper sheet discharge tray  25  and the lower sheet discharge tray  37 , and, when one of the sheet surface detection sensors detects the sheet, a corresponding tray is descended toward a direction of A 2  or B 2  in  FIG.  1   . Further, when one of the sheet surface detection sensors detect a removal of the sheet from the upper sheet discharge tray  25  or the lower sheet discharge tray  37 , a corresponding tray is ascended toward a direction of A 1  or B 1  in  FIG.  1   . Accordingly, the upper sheet discharge tray  25  and the lower sheet discharge tray  37  are controlled to ascend and descend so as to constantly maintain the position of the uppermost sheet of stacked sheets. 
     Configuration of Binding Process Unit 
     Next, the binding process unit  4 A will be described.  FIG.  2    is a perspective view showing the binding process unit  4 A, and some parts of the binding process unit  4 A such as a frame member are omitted herein. 
     As shown in  FIGS.  1  and  2   , the binding process unit  4 A includes a pair of bundle holding flags  30 , an intermediate upper guide  31 , an intermediate lower guide  32 , a holder guide  56 , a crosswise alignment reference plate  52 , an alignment mechanism  33 , and the stapler  51 . 
     The binding process unit  4 A performs the binding process, by the stapler  51 , of the sheet discharged from the inner discharge path  82 , which is composed with an upper conveyance guide  49  and a lower conveyance guide  50 , and stacked on an intermediate stacking portion, and composes a bound sheet bundle. The intermediate upper guide  31  and the intermediate lower guide  32  form the intermediate stacking portion to stack the sheet for processing. The intermediate lower guide  32  serves as a stacking portion which stacks the sheet discharged from the pair of the kick-out rollers  29  of a most downstream roller on the inner discharge path  82 . 
     The pair of the bundle holding flags  30  are disposed downstream of the pair of the kick-out rollers  29 , which are conveyance members, in a pivotable manner. To be noted, the pair of the kick-out rollers  29  are a pair of rollers as a pair of rotary members to nip and discharge the sheet to the intermediate lower guide  32 . Lower surfaces of the pair of the bundle holding flags  30  hold a trailing edge of a preceding sheet, discharged earlier to the intermediate stack portion, and pass a front edge of a succeeding sheet, discharged later by the pair of the kick-out rollers  29 , above the trailing edge of the preceding sheet. That is, the pair of the bundle holding flags  30  work as a unit to prevent an impingement of sheets on each other by moving the trailing edge of the sheet discharged from the pair of the kick-out rollers  29  downwards. The lower surfaces of the pair of the bundle holding flags  30  are disposed in a range of positions in a width direction of the sheet so that the lower surfaces of the pair of the bundle holding flags  30  are capable of holding both edges in the width direction of each size of sheets processable by the binding process unit  4 A. 
     To the intermediate upper guide  31 , the holder guide  56  of a flexible sheet member is fixed, and the holder guide  56  is configured to abut on the intermediate lower guide  32 , and provides a predetermined pressure on an upper surface of the sheet stacked on the intermediate stacking portion. The alignment mechanism  33  is disposed above the intermediate upper guide  31  and the holder guide  56 , and includes a holder  33   c  movably supported by a frame member, not shown, an axis portion  33   b  rotatably supported by the holder  33   c , and an alignment roller  33   a  fixed to the axis portion  33   b.    
     From a lower surface of the holder  33   c , a plurality of longitudinal alignment reference portions  39 , as a first regulation portion, are extended downwards, and tip portions of the plurality of the longitudinal alignment reference portions  39  enter into a plurality of slide grooves  32   a . Therefore, the sheet stacked on the intermediate lower guide  32  securely abuts against the plurality of the longitudinal alignment reference portions  39  by being conveyed by the alignment roller  33   a , and a position of an edge portion of the sheet in a sheet discharge direction CD is regulated. The plurality of the slide grooves  32   a  extend in the sheet discharge direction CD to make the alignment mechanism  33  movable, as described later. To be noted, the plurality of the longitudinal alignment reference portions  39  are disposed downstream of the alignment roller  33   a  in a conveyance direction of the alignment roller  33   a . The crosswise alignment reference plate  52  is arranged in a front direction of the intermediate stacking portion, i.e. outside in a width direction, and extends in the sheet discharge direction CD in which the sheet stacked on the intermediate stacking portion is conveyed to the second discharge path  84 . 
     The axis portion  33   b  of the alignment roller  33   a  is inclined with respect to the sheet discharge direction CD, which is the sheet conveyance direction, and a width direction W orthogonal to the sheet discharge direction CD. Therefore, the alignment roller  33   a , as an alignment unit, rotating around the axis portion  33   b  moves the sheet toward the plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52  by abutting against the sheet stacked on the intermediate lower guide  32 . That is, the plurality of the longitudinal alignment reference portions  39  become an alignment reference of an upstream edge in the sheet discharge direction CD, and the crosswise alignment reference plate  52  becomes an alignment reference of the sheet in a width direction W. 
     The alignment roller  33   a  is controlled to intermittently rotate at a time in a predetermined timing by a driving transmission unit, which is not shown, and rotates by rotation of the axis portion  33   b . The alignment roller  33   a  is formed with molding an elastic material such as a synthetic rubber and an elastomer resin, and a peripheral surface is adjusted to have a predetermined friction coefficient. Further, viewing from an axial direction of the axis portion  33   b , the circumference of the alignment roller  33   a  is noncircular. 
     In a stand-by state before the sheet is discharged to the intermediate stacking portion, a rotation angle of the alignment roller  33   a  is maintained so that a roller portion of the alignment roller  33   a  is not exposed from the intermediate upper guide  31 . Then, during a one revolution of the alignment roller  33   a , the roller portion of the alignment roller  33   a  is exposed from an opening portion  33   d  provided in the holder  33   c  and an opening portion  31   a  provided in the intermediate upper guide  31 . Then, the roller portion of the alignment roller  33   a  abuts against the upper surface of the uppermost sheet stacked on the intermediate lower guide  32 , and provides a conveyance force. A contact pressure of the alignment roller  33   a  on the sheet is adjusted so that the alignment roller  33   a  slips after the sheet has abutted on the plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52 . 
     The sheet aligned by the crosswise alignment reference plate  52 , the plurality of the longitudinal alignment reference portions  39 , and the alignment mechanism  33  is pushed out in the sheet discharge direction CD as the alignment mechanism  33  is moved by a driving unit, not shown, in the sheet discharge direction CD. 
     Movement of Binding Process Unit 
     Next, a movement of the binding process unit  4 A will be described referring to  FIGS.  3 A to  6 B . As shown in  FIGS.  3 A and  3 B , when a first sheet S 1  of the sheet starts entering into the intermediate stacking portion of the binding process unit  4 A, the pair of the bundle holding flags  30  are lifted accompanied with an entrance of the sheet S 1 , and retreat from a sheet discharging path. Then, as shown in  FIGS.  3 C and  3 D , after a trailing edge of the sheet S 1  has passed the pair of the kick-out rollers  29 , the pair of the bundle holding flags  30  return to a stand-by position, and drop the sheet S 1  on the intermediate lower guide  32 . Herewith, the sheet S 1  is in a state of temporally nipped with the holder guide  56  and the intermediate lower guide  32 . 
     Next, as shown in  FIGS.  4 A and  4 B , as the alignment roller  33   a  is driven in an arrow N direction, the sheet S 1  is abutted on plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52 . Thus, the sheet S 1  is aligned along the plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52 . As shown in  FIGS.  4 C and  4 D , when the alignment roller  33   a  retreats above the intermediate upper guide  31 , a succeeding sheet S 2  starts entering into the binding process unit  4 A. Herewith, the pair of the bundle holding flags  30  are lifted again accompanied with an entrance of the sheet S 2 . 
     As shown in  FIGS.  5 A and  5 B , after a trailing edge of the sheet S 2  has passed the pair of the kick-out rollers  29 , the pair of the bundle holding flags  30  return to the stand-by position, and drop the sheet S 2  on the intermediate lower guide  32 . Herewith, the sheet S 2  is in a state of temporally nipped by the holder guide  56  and the intermediate lower guide  32 . Further, as shown in  FIGS.  5 C and  5 D , as the alignment roller  33   a  is driven in the arrow N direction, the sheet S 2  is abutted on the plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52 . Thus, the sheet S 2  is aligned along the plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52 . 
     Hereafter, a sheet alignment movement is repeated until the alignment of a last sheet constituting the sheet bundle is completed. Then, when the sheet alignment movement on the last sheet is completed, the stapler  51  binds the predetermined position of the sheet bundle. As shown in  FIGS.  6 A and  6 B , when a binding movement is carried out by the stapler  51 , the alignment mechanism  33  moves in parallel in the sheet discharge direction CD, and the sheet bundle is pushed out in the sheet discharge direction CD by the plurality of the longitudinal alignment reference portions  39  of the alignment mechanism  33 . Then, the sheet bundle is delivered to the pair of the bundle discharge rollers  36 , and stacked on the lower sheet discharge tray  37 . 
     Comparative Example 
     Next, with reference to  FIGS.  7 A and  7 B , a comparative example to this embodiment will be described. A binding process unit  400 A of the comparative example and the binding process unit  4 A of this embodiment are similar in structures except that a crosswise alignment reference plate  452  is unmovable to the intermediate lower guide  32  in the binding process unit  400 A. 
     For example, in a case where the binding process unit  400 A is capable of processing sheet sizes of an A5-size to a legal-size and the stapler  51  binds a corner portion of these A5 to legal-size sheets, the stapler  51  moves in a range of positions P 1  to P 3 . Then, it is unable to dispose a crosswise alignment reference plate  452  within a range of the positions P 1  to P 3 , which is a moving range of the stapler  51 , to prevent an impingement of the stapler  51  on the crosswise alignment reference plate  452 . Therefore, the crosswise alignment reference plate  452  is fixed at a position shown in  FIGS.  7 A and  7 B . 
     However, as shown in  FIG.  7 B , in a case where the binding process is performed, for example, on the legal-size sheet, since the crosswise alignment reference plate  452  is substantially separated from the stapler  51  and the plurality of the longitudinal alignment reference portions, not shown, the sheet may be rotated to cause a deteriorated alignment. 
     Therefore, in this embodiment, as shown in  FIG.  8 A , a moving unit  70  is provided to the binding process unit  4 A. The moving unit  70  includes a driving motor M as a driving source, a driving pully  71  driven by the driving motor M, a driven pully  72 , a belt  73  of endless-shaped wound around by the driving pully  71  and the driven pulley  72 , and a link member  74  coupled to the belt  73 . The link member  74  supports the stapler  51  and the crosswise alignment reference plate  52 . That is, the belt  73  is coupled to the stapler  51 , as a binding member, and the crosswise alignment reference plate  52 , as a second regulation member, via the link member  74 . 
     When the driving pulley  71  is rotated by the driving motor M from a state shown in  FIG.  8 A  in an arrow R 1  direction, the belt  73  rotates in an arrow R 2  direction, and the link member  74  fixed to the belt  73  moves accompanied by the belt  73 . Thus, the stapler  51  and the crosswise alignment reference plate  52  moves in the sheet discharge direction CD. In other words, the moving unit  70 , accompanied with a movement of the stapler  51  in the sheet discharge direction CD, moves the crosswise alignment reference plate  52  in the sheet discharge direction CD. 
     Herewith, a design restriction of the comparative example, as described above, of unable to dispose the crosswise alignment reference plate  52  within the moving range of the stapler  51  is eliminated, and it is possible to dispose the crosswise alignment reference plate  52  in adjacent to the stapler  51  and the plurality of the longitudinal alignment reference portions  39 . In more particular, for example, in a case of the binding process to the legal-size sheet as shown in  FIG.  9 A  and also even in a case of the binding process to the A5-size sheet as shown in  FIG.  9 B , it is possible to dispose the crosswise alignment reference plate  52  in adjacent to the stapler  51  and the plurality of the longitudinal alignment reference portions  39 . Therefore, it is possible to improve the alignment of the sheet even in a case where the postprocessing apparatus  4  is capable of performing the binding process to a plurality of sizes of the sheet. 
     Second Embodiment 
     Although a second embodiment according to the present invention will be described next, a configuration of the crosswise alignment reference plate  52  of the first embodiment is changed in the second embodiment. Therefore, drawings of configurations similar to the first embodiment are omitted herein, or described by putting a same mark on drawings. 
     A binding process unit  40 B according to the second embodiment includes, as shown in  FIGS.  10 A and  10 B , a movable crosswise alignment reference member  152  as the second regulation member and a fixed crosswise alignment reference member  60   a . The fixed crosswise alignment reference member  60   a , as a third regulation member, is disposed at an opposite side of the stapler  51  across the movable crosswise alignment reference member  152 . In other words, the fixed crosswise alignment reference member  60   a  is disposed at a different position from the movable crosswise alignment reference member  152  in the sheet discharge direction CD. These crosswise alignment reference members, i.e. the movable crosswise alignment reference member  152  and the fixed crosswise alignment reference member  60   a  regulate an edge position in a width direction of the sheet stacked on the intermediate lower guide  32 . To be noted, a method of the alignment is similar to a method described in the first embodiment. 
     The movable crosswise alignment reference member  152  moves in a similar configuration of the moving unit  70 , as described in  FIGS.  8 A and  8 B , in the sheet discharge direction CD accompanied with the movement of the stapler  51 . On the other hand, the fixed crosswise alignment reference member  60   a  is fixed to the intermediate lower guide  32 , and does not move when the stapler  51  and the movable crosswise alignment reference member  152  are moved by the moving unit  70 . To be noted, the fixed crosswise alignment reference member  60   a  is disposed at a position where the fixed crosswise alignment reference member  60   a  is able to abut on a minimum size sheet which the binding process unit  40 B can process. 
     As shown in  FIG.  10 A , in a case of the alignment of the legal-size sheet, a distance between the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  152  is a distance D 1 . Then, at this time, a distance between the movable crosswise alignment reference member  152  and the stapler  51  is a distance D 3 . On the other hand, as shown in  FIG.  10 B , in a case of the alignment of the A5-size sheet, the distance between the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  152  is a distance D 2 . At this time, the distance between the movable crosswise alignment reference member  152  and the stapler  51  is the distance D 3  which is the same as the case of  FIG.  10 A . 
     Thus, the distance D 3  of the distance between the movable crosswise alignment reference member  152  and the stapler  51  is set to be smaller than the distance D 1  and the distance D 2  of the distance between the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  152 . That is, it is possible to dispose the crosswise alignment reference plate  52  in adjacent to the stapler  51  and the plurality of the longitudinal alignment reference portions  39  (refer to  FIG.  9 A ). Accordingly, it is possible to improve the alignment of the sheet even in a case of the postprocessing apparatus which is capable of processing the plurality of the sizes of the sheet. 
     As described above, although in the first embodiment the width direction W of the sheet is aligned by the crosswise alignment reference plate  52  which is configured with one piece of a large size member, the sheet is aligned by two pieces of members of the movable crosswise alignment reference member  152  and the fixed crosswise alignment reference member  60   a  in this embodiment. Thus, it is possible to reduce a size of each of the movable crosswise alignment reference member  152  and the fixed crosswise alignment reference member  60   a , and is possible to reduce a size of a whole apparatus and bring a cost down. 
     Third Embodiment 
     Although a third embodiment according to the present invention will be described next, a configuration of the fixed crosswise alignment reference member  60   a  of the second embodiment is changed in the third embodiment. Therefore, drawings of configurations similar to the second embodiment are omitted herein, or described by putting a same mark on drawings. 
     As shown in  FIGS.  11 A and  11 B , a binding process unit  40 C according to the third embodiment includes movable crosswise alignment reference members  60   b  and  152 . As a fourth regulation member, the movable crosswise alignment reference member  60   b  is disposed at an opposite side of the stapler  51  across the movable crosswise alignment reference member  152  in the sheet discharge direction CD. In other words, the movable crosswise alignment reference member  60   b  is disposed at a different position from the movable crosswise alignment reference member  152  in the sheet discharge direction CD. These movable crosswise alignment reference members  60   b  and  152  regulate the edge position of the sheet stacked on the intermediate lower guide  32  in the width direction. To be noted, a method of the alignment of the sheet is similar to the method described in the first embodiment. 
     The movable crosswise alignment reference members  60   b  and  152  are configured to be independently movable each other in the sheet discharge direction CD. For example, the movable crosswise alignment reference member  152  moves by a similar configuration of the moving unit  70 , described in  FIGS.  8 A and  8 B , in the sheet discharge direction CD accompanied with the movement of the stapler  51 . On the other hand, the movable crosswise alignment reference member  60   b  is coupled to a belt which is driven by a different driving source from the driving motor M, and configured to be movable by rotation of the belt. 
     By configurations as described above, for example, as shown in  FIG.  11 A , it is possible to dispose the movable crosswise alignment reference members  60   b  and  152  symmetrically each other with respect to a center line L 1  of the sheet discharge direction CD. Further, for example, as shown in  FIG.  11 B , it is possible to dispose the movable crosswise alignment reference members  60   b  and  152  at various positions in accordance with characteristics of the sheet such as a weight balance and a surface characteristic. Thus, it is possible to improve the alignment of the sheet of a variety of properties. 
     Fourth Embodiment 
     Although a fourth embodiment according to the present invention will be described next, a configuration of the movable crosswise alignment reference member  152  of the second embodiment is changed in the fourth embodiment. Therefore, drawings of configurations similar to the second embodiment are omitted herein, or described by putting a same mark on drawings. 
     As shown in  FIGS.  12 A and  12 B , although a binding process unit  40 D according to the fourth embodiment is similar to the second embodiment in terms of configurations during an alignment movement, as shown in  FIGS.  12 A and  12 B , the stapler  51  is movable to an upper left side in  FIGS.  12 A and  12 B  to perform the binding process after the completion of the alignment movement. Although the movable crosswise alignment reference member  252 , as the second regulation member, moves accompanied with the movement of the stapler  51 , the movable crosswise alignment reference member  252  stops before abutting against the fixed crosswise alignment reference member  60   a  by abutting against a stopper portion  32   b.    
     Referring to  FIGS.  13  and  14   , movements of the stapler  51  and the movable crosswise alignment reference member  252  will be described in detail. The binding process unit  40 D includes a moving unit  70 D which moves the movable crosswise alignment reference member  252  to the sheet discharge direction CD accompanied with the movement of the stapler  51  in the sheet discharge direction CD. The moving unit  70 D includes the driving motor M, the driving pulley  71  driven by the driving motor M, the driven pulley  72 , the belt  73  of endless-shaped wound around by the driving pully  71  and the driven pully  72 , a holder  274 , a slider  77 , and a stopper portion  32   b . The fixed crosswise alignment reference member  60   a  is fixed to the intermediate lower guide  32 . 
     To the belt  73 , the holder  274  is coupled, and to the holder  274 , the stapler  51  is fixed. The slider  77  is held by a guide rib  232   a , provided in the intermediate lower guide  32 , and guide shaft  75  in a manner of capable of sliding smoothly in the sheet discharge direction CD, and the movable crosswise alignment reference member  252  is fixed to the slider  77 . Further, a spring  76  is coupled to the slider  77 , the spring  76 , as an urging member, urges the slider  77  downstream in the sheet discharge direction CD. A contact portion  77   a  of the slider  77  is pressed on a contact portion  274   a  of the holder  274  by an urging force of the spring  76 . Herewith, the slider  77  and the movable crosswise alignment reference member  252  fixed to the slider  77  follow the movement of the stapler  51  in the sheet discharge direction CD. 
     When the stapler  51  moves downstream in the sheet discharge direction CD, a part of the slider  77  abuts against the stopper portion  32   b  provided at a lower side of the intermediate lower guide  32 , and sliding movements of the slider  77  and the movable crosswise alignment reference member  252  fixed to the slider  77  are stopped. At this time, the movable crosswise alignment reference member  252  stops upstream of the fixed crosswise alignment reference member  60   a  in the sheet discharge direction CD. When the belt  73  is driven in this condition, while the slider  77  and the movable crosswise alignment reference member  252  are stopping, the stapler  51  moves downstream in the sheet discharge direction CD. That is, the stapler  51  relatively moves with respect to the movable crosswise alignment reference member  252  in the sheet discharge direction CD. When the stapler  51  moves upstream in the sheet discharge direction CD, the slider  77  stopped by abutting against the stopper portion  32   b  abuts on the contact portion  274   a  of the holder  274  again, and the stapler  51  and the slider  77  move integrally. 
       FIG.  15    is a schematic view showing the stapler  51  and the movable crosswise alignment reference member  252 . As shown in  FIG.  15   , the stapler  51  includes a recess portion  261  of a rectangular shape with one side open into which a part of the sheet to be processed with the binding process enters, and the movable crosswise alignment reference member  252  includes an abutment portion  260  for an abutment of an edge in the width direction W of the sheet for the binding process. A height L 1  of the abutment portion  260  is configured to be smaller than a height L 2  of the recess portion  261  of the stapler  51 . That is, the stapler  51  is disposed not to overlap with the movable crosswise alignment reference member  252  when the stapler  51  and the movable crosswise alignment reference member  252  are viewed in the sheet discharge direction CD, and is movable in the sheet discharge direction CD across the movable crosswise alignment reference member  252  by the moving unit  70 D. In more particular, when the stapler  51  moves in the sheet discharge direction CD across the movable crosswise alignment reference member  252 , the abutment portion  260  passes through an inside of the recess portion  261 , and does not interfere with the stapler  51 . Further, the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  252  are similar to each other in shape. Therefore, the stapler  51  is disposed not to overlap with the fixed crosswise alignment reference member  60   a  when the stapler  51  and the fixed crosswise alignment reference member  60   a  are viewed in the sheet discharge direction CD, and is movable in the sheet discharge direction CD across the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  252 . 
     By configurations as described above, as shown in  FIGS.  12 A and  12 B , in a case where the binding process is performed on an upper left side of the sheet in  FIGS.  12 A and  12 B , it is possible to avoid interference of the stapler  51  with the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  252 . To be noted, the stapler  51  may perform the binding process not only on the upper left side of the sheet but also on a plurality of positions from a lower left side to the upper left side of the sheet in  FIGS.  12 A and  12 B . Further, as described in the third embodiment, it is acceptable to configure the fixed crosswise alignment reference member  60   a  as the movable crosswise alignment reference member  60   b . Herewith, the alignment of the sheet is improved in a case where the binding process is performed on the upper left side of the sheet of a variety of properties. 
     OTHER EMBODIMENTS 
     In the first to the fourth embodiment described above, the postprocessing apparatus  4  of directly coupled to the image forming apparatus  1  has been described as an example of the sheet processing apparatus. However, the present invention is applicable to the sheet processing apparatus which receives the sheet from the image forming apparatus  1  via an intermediate unit (such as a relay conveyance unit furnished in a discharge space of an in-drum delivery type image forming apparatus). Further, the image forming system with the sheet processing apparatus and the image forming apparatus involves a system in which a module having functions of the image forming apparatus  1  and the postprocessing apparatus  4  is mounted in a single casing. 
     Further, the stapler  51  is an example of the binding unit which performs the binding process to the sheet, and it is acceptable to apply, for example, the needleless binding unit in place of the stapler  51  using staples. 
     Further, although in the first to the third embodiment, the stapler  51  is coupled to the crosswise alignment reference plate  52  or the movable crosswise alignment reference member  152  by the moving unit  70 , it is not limited to this. For example, it is acceptable to fix the stapler  51  directly to the crosswise alignment reference member. Further, although in the second to the fourth embodiment two pieces of crosswise alignment reference members are provided, it is not limited to this, and acceptable to provide equal to or more than three pieces of crosswise alignment reference members. 
     In the fourth embodiment described above, the stapler  51  is configured to be movable across the fixed crosswise alignment reference member  60   a  and the movable crosswise alignment reference member  252 , it is not limited to this. For example, it is acceptable to configure the stapler  51  movable across the movable crosswise alignment reference member  252  but not movable across the fixed crosswise alignment reference member  60   a . Further, although the movable crosswise alignment reference member  252  stops by the slider  77  abutting against the stopper portion  32   b  provided in the lower part of the intermediate lower guide  32 , it is not limited to this. For example, it is acceptable to provide the stopper portion  32   b  in other members than the intermediate lower guide  32 , and to configure the slider  77  or the movable crosswise alignment reference member  252  to stop by abutting against the fixed crosswise alignment reference member  60   a  directly. Further, similar to the fourth embodiment, it is acceptable to configure the stapler  51  in the first embodiment movable across the crosswise alignment reference plate. 
     Further, although, in the first to the fourth embodiment described above, the sheet is configured to be aligned by abutting against the plurality of the longitudinal alignment reference portions  39  and the crosswise alignment reference plate  52  by the alignment mechanism  33 , it is not limited to this. For example, it is acceptable to apply a configuration to respectively align the width direction and the sheet conveyance direction of the sheet by a jogger fence and a paddle member. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2019-107294, filed Jun. 7, 2019, and Japanese Patent Application No. 2020-047782, filed Mar. 18, 2020, which are hereby incorporated by reference herein in their entirety.