JP2009046259A - Paper post-processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper post-processing device capable of easily creating a small booklet having a good appearance and capable of being accurately folded at a position of a staple and capable of being opened and closed smoothly. <P>SOLUTION: The paper post-processing device 1 includes a centering part 25 as a paper conveying means, a folding part 21 for folding paper into two by creasing the paper in a paper width direction which is a right angle to a paper conveying direction and a staple detection means 27, arranged at a predetermined distance X apart from the folding part 21, for detecting the position of the staple ST driven into the paper and, when the staple detection means 27 detects the staple ST on the paper, moves the paper toward the folding part 21 by the predetermined distance X by the centering part 25. Thus, it is possible to identify the position where the staple ST actually exists and correctly fold the paper at that position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet post-processing apparatus that is connected to an image forming apparatus such as a copying machine and performs post-processing on a sheet that has been printed and discharged.

  An image forming apparatus such as a copying machine may be provided with a paper post-processing device that performs post-processing on paper discharged after printing is completed. The sheet post-processing device is arranged side by side with the image forming apparatus, and after performing a stapling process for driving staples on the sheet, a bi-folding process for bending the sheet, and the like, the sheet is discharged to the sheet discharge unit.

  In such a sheet post-processing apparatus, in the folding process of the sheet, the sheet is folded in a crease in the sheet width direction perpendicular to the normal sheet conveying direction. When the paper reaches the folding portion where the paper is folded in half, a blade-like member extending in the paper width direction is pressed from one side of the paper, and the blade-like member further pushes the paper surface to the other side. Is pushed in the normal direction, and a crease is formed at the location, and the crease is conveyed as a downstream end and discharged.

  In the stapling process, stapling is driven into the approximate center of the normal paper conveyance direction. Then, the above-described bi-folding process is folded at a substantially central portion in the sheet conveyance direction, as in the stapling process. Therefore, in the post-processing applied to the paper that has been printed by the paper post-processing device, the folding position of the paper generally matches the position of the staple. As a result, the sheet post-processing apparatus can create a booklet in which a plurality of sheets are folded at the longitudinal center (conveyance direction center) and subjected to stapling at the folded portion.

Patent Documents 1 and 2 show a paper post-processing apparatus that performs such a paper folding process. The paper post-processing apparatus described in Patent Documents 1 and 2 is a general type that is arranged side by side with an image forming apparatus. The structure is made.
Japanese Patent Laid-Open No. 2000-72320 (page 6, FIG. 3-4) JP 2001-146363 A (page 5-6, FIG. 4)

  In the paper post-processing devices described in Patent Documents 1 and 2, paper size information is acquired in advance, and based on this paper size, stapling and bi-folding can be executed at the center of the paper conveyance direction at each location. The paper stopper member at the downstream end in the transport direction is moved so that the folding position of the paper matches the position of the staple. However, in this method, since the sheet is moved so as to set the processing position at the center in the transport direction in the staple processing unit and the bending unit, the processing position may be shifted. As a result, there is a possibility that a booklet that does not match the folding position and the staple position, looks bad, and is difficult to open and close is produced. Therefore, when the folding process is performed after the stapling process, it is necessary to identify the position where the stapling actually exists and then bend the part accurately.

  The present invention has been made in view of the above points, and in the case where the folding process is performed after the stapling process, a booklet that can be accurately folded at the position where the stapling exists, has a good appearance, and can be opened and closed smoothly. An object of the present invention is to provide a high-performance sheet post-processing apparatus that can be easily created.

  In order to solve the above-described problems, the present invention includes a folding unit that folds a sheet in a crease in the sheet width direction perpendicular to the sheet conveyance direction, and the folding unit approximately at the center in the sheet conveyance direction. A sheet stacking unit, a sheet conveying unit that moves the sheet on the sheet stacking unit, a staple detection unit that is disposed opposite to the surface of the sheet on the sheet stacking unit and detects the position of the staple that has been driven into the sheet; When the stapling detection means detects stapling on the paper, the paper transporting means moves the paper toward the folding portion so that the stapling position coincides with the folding position.

  In the sheet post-processing apparatus having the above-described configuration, the staple detection unit is disposed at a predetermined distance in the sheet conveyance direction with respect to the bent portion, and when the staple detection unit detects a staple on the sheet, The sheet is moved by the sheet conveying unit toward the bent portion along the sheet conveying direction by the predetermined distance.

  Further, the paper post-processing apparatus having the above-described configuration includes a folding unit configured around the folding portion, and the stapling detection unit is mounted on the folding unit.

  Further, the sheet post-processing apparatus having the above-described configuration includes a staple processing unit that drives staples on the sheet, and the bending portion is disposed downstream of the staple processing unit in the sheet conveyance direction.

  According to the configuration of the present invention, in the paper post-processing apparatus, the folding portion that folds the paper in a crease in the paper width direction perpendicular to the paper conveyance direction, and the folding portion at the substantially center in the paper conveyance direction. A paper stacking unit, paper transporting means for moving the paper on the paper stacking unit, and stapling detection that detects the position of the staple that has been placed on the paper, facing the surface of the paper on the paper stacking unit. And when the staple detection means detects a staple on the paper, the paper transport means moves the paper toward the folding portion so that the staple position coincides with the folding position. Therefore, it is possible to accurately bend the sheet at the position after identifying the position where the staple is actually present. Accordingly, it is possible to provide a high-performance sheet post-processing apparatus that can easily create a booklet that has a good appearance and can be opened and closed smoothly.

  The staple detection means is disposed at a predetermined distance in the paper conveyance direction with respect to the bent portion. When the staple detection means detects a staple on the paper, the paper conveyance means causes the paper to be removed from the predetermined section. Since the sheet is moved toward the folding part along the sheet conveying direction by the distance, the folding part and the staple position can be automatically matched with a simple configuration. Therefore, it is possible to easily create a booklet that can be accurately folded and smoothly opened / closed by identifying the position where staples actually exist while suppressing a significant increase in cost and then folding the paper accurately at that location. Therefore, it is possible to provide a high-performance sheet post-processing apparatus that can perform such a process.

  In addition, since the folding unit is configured with the folding unit as a center, and the staple detection unit is mounted on the folding unit, the folding unit and the staple detection unit can be arranged closer to each other. it can. Thereby, after the staple on the paper is detected by the staple detection means, the distance for moving the paper toward the bent portion can be made as short as possible. As a result, the bent portion and the staple position can be matched with high accuracy. Therefore, it is possible to create a booklet that has a better appearance and can be opened and closed smoothly.

  In addition, a sheet post-processing apparatus connected to an image forming apparatus includes a staple processing unit that drives staples on a sheet, and a folding portion is often disposed on the downstream side of the staple processing unit in the sheet conveyance direction. Thus, by separating the folding unit having the bent portion and the stapling unit, the configuration of the apparatus is easy, and the stapling process and the bi-folding process can be performed efficiently. However, on the other hand, there is also a problem that a deviation easily occurs between the bent portion and the staple position. With respect to such a problem, in the sheet post-processing apparatus of the present invention, by arranging the bent portion on the downstream side in the sheet conveying direction of the staple processing unit, the bent portion and the staple position can be automatically matched. Therefore, it is possible to obtain a sheet post-processing apparatus that can bend accurately at a position where staples exist while efficiently performing the stapling process and the bi-folding process.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, the outline and operation of the paper post-processing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional front view of a paper post-processing apparatus. Note that dotted arrows in the figure indicate the sheet conveyance path and the conveyance direction.

  The paper post-processing apparatus 1 shown in FIG. 1 is detachably connected to the paper discharge side of the image forming apparatus 100. The image forming apparatus 100 is on the right side of the sheet post-processing apparatus 1 in FIG. The sheet post-processing apparatus 1 includes a punching apparatus 2, a staple processing unit 10, and a folding unit 20 that perform punching processing, stapling processing, and bi-folding processing on the paper discharged from the image forming apparatus 100.

  The punch device 2 is disposed on the upper portion of the paper post-processing device 1. The sheet discharged from the image forming apparatus 100 passes through the sheet carry-in port 3 provided on the side surface of the sheet post-processing apparatus 1 and reaches the position of the punch apparatus 2. If a punching process command has been received, the punching process is performed on the sheet. The paper that has passed through the portion of the punching device 2 reaches the paper distribution unit 4 downstream thereof.

  The paper sorting unit 4 is provided with a plurality of movable guides 5. Each movable guide 5 is provided so as to be rotatable about an axis extending in the sheet width direction perpendicular to the sheet conveyance direction, and switches and distributes the sheet conveyance direction in a wedge shape when viewed from the axis direction. The paper distribution unit 4 distributes the paper to the main discharge tray 6 or the sub discharge tray 7 when no processing is performed on the paper that has passed through the punch device 2. When stapling or bi-folding is further performed on the paper, the paper is sorted downward.

  The staple processing unit 10 is disposed below the punch device 2 and the paper sorting unit 4 and at a substantially vertical central portion of the paper post-processing device 1. The staple processing unit 10 includes a stack tray 11, a cover tray 12, a lower end stopper 13, an upper end presser 14, a transport device 15, and a staple device 16.

  The stack tray 11 and the cover tray 12 are disposed to face each other with a predetermined space therebetween. This space is a sheet processing space S, which is formed so as to extend up and down at an angle slightly inclined from the vertical direction, and the sheet conveyed from above is fed into this space.

  A lower end stopper 13 is provided at the lower end of the sheet processing space S of the stack tray 11, and an upper end presser 14 is provided at the upper end. The lower end stopper 13, the upper end pressing member 14, and the paper in the paper processing space S can be independently moved in the vertical direction by the transport device 15. The sheet fed into the sheet processing space S is received by the lower end stopper 13. Then, with the lower end stopper 13 stopped, the upper end presser 14 lightly presses the upper end of the sheet bundle toward the lower end stopper 13, thereby aligning the upper end of the sheet bundle.

  Staple processing by the stapling device 16 is performed on the sheet bundle aligned as described above. The stapling device 16 is arranged at two locations side by side in the paper width direction, that is, the paper surface depth direction in FIG. In the staple processing unit 10, by driving the transport device 15, it is possible to perform stapling processing such as leading edge binding for driving the staple at the leading end of the sheet bundle and center binding for driving the staple at the center in the conveyance direction of the sheet bundle. . When the stapling process is completed and the folding process is not performed, the sheet bundle is conveyed to the upper main discharge tray 6 by the conveying device 15, and when the folding process is performed, the sheet bundle is conveyed downward.

  The folding unit 20 is disposed on the downstream side of the staple processing unit 10 in the sheet conveyance direction, that is, below the staple processing unit 10 and at the lowermost part in the vertical direction of the sheet post-processing apparatus 1. The folding unit 20 is configured around a folding unit 21 that folds a sheet in a crease in the sheet width direction perpendicular to the sheet conveyance direction, and further includes a booklet discharge tray 22. The sheet bundle subjected to the staple processing by the staple processing unit 10 is folded by the folding unit 21 and is discharged into the booklet discharge tray 22 as a booklet.

  Next, the detailed configuration of the bending unit 20 will be described with reference to FIG. 2 in addition to FIG. FIG. 2 is a vertical sectional front view of the folding unit of the sheet post-processing apparatus. In FIG. 2, drawing of the booklet discharge tray 22 drawn in FIG. 1 is omitted. In addition, the dotted line arrows in the figure indicate the sheet conveyance path and the conveyance direction.

  As shown in FIGS. 1 and 2, the folding unit 20 includes a folding unit 21, a booklet discharge tray 22, a paper stacking unit 23, a conveyance roller pair 24, a center alignment unit 25, a discharge unit 26, and a staple detection unit 27. Yes.

  Inside the folding unit 20, a paper stacking unit 23 extending in the paper transport direction in a shape slightly inclined from the horizontal is disposed. The sheet stacking unit 23 extends obliquely downward with respect to the upper staple processing unit 10 that receives the sheet bundle. A film-like member (not shown) made of PET (polyethylene terephthalate) or the like is provided at the ceiling of the paper transport space of the paper stacking unit 23, and the elastic sheet is used to attach the paper bundle downward. It is fast.

  Further, in the sheet stacking unit 23, a conveyance roller pair 24, a bending unit 21, and a centering unit 25 are arranged in this order toward the downstream side, and the bending unit 21 is provided at a substantially center in the sheet conveying direction. The discharge unit 26 extends upward in such a manner as to be branched at the folding unit 21 with respect to the paper stacking unit 23, and a booklet discharge tray 22 (see FIG. 1) is provided at the downstream end thereof.

  A pair of transport rollers 24 is disposed upstream of the folding unit 21 disposed substantially at the center of the folding unit 20 in the sheet transport direction. The transport roller pair 24 transports the sheet bundle received from the staple processing unit 10 and fed to the transport nip formed by the pressure contact of the paired rollers 24 a and 24 b toward the folding unit 21. The transport roller pair 24 can release the transport nip by moving the upper roller 24a upward.

  The folding unit 21 is disposed downstream of the conveying roller pair 24 and includes a reciprocating mechanism 28, a folding blade 29, and a folding roller pair 30.

  The reciprocating mechanism 28 includes a support member 28a for supporting the bending blade 29, and a crank mechanism 28b, which is disposed in a sheet conveying space of the sheet stacking portion 23 having a shape slightly inclined from the horizontal, and a portion extending below the sheet conveying space. . The reciprocating mechanism 28 changes the rotational power of a motor (not shown) to linear motion by the action of the crank mechanism 28b, and moves the support member 28a in a direction perpendicular to the paper stacking portion 23, that is, in the direction of the white arrow in FIG. It can be reciprocated.

  When the support member 28 a is moved to the lowermost position, the tip of the bending blade 29 is positioned below the sheet stacking portion 23. When the support member 28 a is moved to the uppermost position, the leading end of the folding blade 29 protrudes further upward than the sheet stacking portion 23 and reaches the conveyance nip portion of the folding roller pair 30.

  The bending roller pair 30 is disposed above the reciprocating mechanism 28. One roller 30a of the bending roller pair 30 is rotated by obtaining power from a motor (not shown), and the other roller 30b is rotated in accordance with the rotation of the roller 30a by being in pressure contact therewith. The folding roller pair 30 forms a conveyance nip by the pair of rollers 30a and 30b being pressed against each other, but the conveyance nip can be released by separating the roller 30b.

  With the above-described configuration, the folding unit 21 folds the sheet on the sheet stacking unit 23 by pushing the sheet on the sheet stacking unit 23 upward with the folding blade 29 and forming a crease in the sheet width direction perpendicular to the sheet conveying direction. Apply.

  The center alignment unit 25 is disposed downstream of the bending unit 21 and includes a center alignment cursor 31 and a moving mechanism 32.

  The center alignment cursor 31 is arranged on the sheet stacking unit 23 and has a shape for receiving the downstream end of the sheet bundle. The moving mechanism 32 includes an endless belt 32a that extends along the paper transport direction of the paper stacking unit 23 and rotates. The center alignment cursor 31 is attached to the upper surface of the belt 32a and can be moved in the paper transport direction by the moving mechanism 32. In this way, the center aligning unit 25 functions as a paper transport unit that moves the paper on the paper stacking unit 23.

  The staple detection unit 27 is disposed upstream of the folding unit 21 in the sheet conveyance direction and above the conveyance roller pair 24 and the folding unit 21, that is, facing the surface of the sheet on the sheet stacking unit 23. ing. Further, the staple detection means 27 is arranged in two places corresponding to the staple position in the paper width direction. The staple detection unit 27 includes an optical sensor, irradiates light toward the paper stacking unit 23, receives the reflected light, and detects the position of the staple that has been driven into the paper. As shown in FIG. 2, the staple detection means 27 is arranged at a predetermined distance X with respect to the position of the bending blade 29 of the bending portion 21. Further, the staple detection means 27 may be constituted by a metal detector that employs a magnetic induction method as a detection method.

  Next, the operation of the bending unit 20 having the above configuration will be described with reference to FIGS. 4 to 6 with reference to FIG. 3 in addition to FIG. FIG. 3 is a flowchart showing the operation of the sheet post-processing apparatus when the stapling process and the bi-folding process are performed with the center binding on the sheet that has been printed. 4 is a vertical sectional front view of the folding unit similar to FIG. 2 and shows the initial stage of entering the sheet bundle. FIG. 5 is a vertical sectional front view of the folding unit similar to FIG. FIG. 6 is a vertical sectional front view of a folding unit similar to FIG. 5 and shows a state in which the staple position is matched with the folding position.

  When printing is completed in the image forming apparatus 100, the process proceeds to step # 101 shown in FIG. 3, and the staple processing unit 10 (see FIG. 1) of the sheet post-processing apparatus 1 performs the stapling process at the center of the sheet bundle conveyance direction. The At this time, the stapling position is set at the center of the sheet conveyance direction based on the sheet size information received from the image forming apparatus 100. Thereafter, the sheet bundle is conveyed toward the folding unit 20.

  When the process proceeds to step # 102 in FIG. 3, in the folding unit 20, as shown in FIG. 4, before the centering cursor 31 receives the sheet bundle, the sheet size is shifted downstream from the position of the folding blade 29 of the folding unit 21. It moves toward the upstream side from the standby position, which is a distance L that is ½ of. The moving distance of the center alignment cursor 31 is X + Y. Note that the distance X is the distance between the staple detection means 27 and the position of the bending blade 29 of the bending portion 21 as described above. The distance Y is an arbitrary distance.

  As described above, the center alignment cursor 31 is moved from the standby position to the initial position of X + Y before receiving the sheet bundle, so that when the sheet is moved while stapling is detected, the center alignment cursor 31 is efficiently moved without extra movement. It is possible to execute stapling detection.

  When the process proceeds to step # 103 in FIG. 3, the sheet bundle P is conveyed until it comes into contact with the center alignment cursor 31, as shown in FIG. At this time, the transport roller pair 24 is used for paper transport, but the transport nip of the transport roller pair 24 is released immediately before the downstream end of the paper bundle P contacts the centering cursor 31 (see FIG. 5). Makes the downstream end of the sheet bundle P abut against the centering cursor 31 by inertia.

  When the process proceeds to step # 104 in FIG. 3, the center alignment cursor 31 gradually moves downstream in the center alignment unit 25. At this time, the sheet bundle P moves downstream together with the center alignment cursor 31. Then, the staple detection unit 27 starts detecting the staple ST on the paper.

  In step # 105, it is determined whether the staple detection unit 27 has detected the staple ST on the paper. Then, the operations of Step # 104 and Step # 105 are repeated until the staple ST can be detected. During this time, the sheet bundle P on the sheet stacking section 23 is gradually moved downstream by the function of the center aligning section 25, and the staple detection means 27 irradiates light toward the sheet bundle P to detect the staple ST. to continue.

  In step # 105, when the staple detection means 27 detects the staple ST as shown in FIG. 5, the conveyance of the sheet bundle P is temporarily stopped, and the process proceeds to step # 106.

  When the process proceeds to step # 106 in FIG. 3, the sheet bundle P is moved by the predetermined distance X toward the downstream side together with the center alignment cursor 31, as shown in FIG. As described above, the predetermined distance X is the distance between the staple detection means 27 and the position of the folding blade 29 of the folding portion 21, and therefore the detected position of the staple ST is the folding blade 29 of the folding portion 21. Matches the position of.

  In step # 107, the folding unit 21 performs a folding process on the sheet bundle P in half. The sheet bundle P, which has been folded in half and formed into a booklet, passes through the discharge unit 26 and is discharged to the booklet discharge tray 22 (see FIG. 1).

  In this way, the sheet post-processing apparatus 1 includes a folding unit 21 that performs a folding process on the sheet in a crease in the sheet width direction perpendicular to the sheet conveyance direction, and the folding unit 21 is substantially omitted in the sheet conveyance direction. A paper stacking unit 23 provided in the center, a centering unit 25 serving as a paper transporting means for moving the paper on the paper stacking unit 23, and a sheet surface on the paper stacking unit 23 are disposed opposite to each other and driven into the paper. A stapling detection means 27 for detecting the position of the stapling ST, and when the stapling detection means 27 detects the stapling ST on the paper, the center aligning section 25 causes the paper to be stapled at the folding position. Therefore, after the position where the staple ST actually exists is identified, the sheet can be folded accurately at that location. It is possible. Thereby, it is possible to provide a high-performance sheet post-processing apparatus 1 that has a good appearance and can easily create a booklet that can be opened and closed smoothly.

  Further, the staple detection means 27 is arranged at a predetermined distance X in the paper conveyance direction with respect to the bent portion 21. Since the unit 25 moves the sheet by the predetermined distance X toward the folding unit 21 along the sheet conveyance direction, the folding position and the position of the staple ST can be automatically matched with a simple configuration. . Therefore, it is possible to easily create a booklet that can be opened and closed smoothly by identifying the position where the staple ST actually exists while accurately suppressing the cost increase and folding the paper accurately at that location. Thus, it is possible to provide a high-performance sheet post-processing apparatus 1 that can do this.

  The folding unit 20 is configured with the folding unit 21 as the center, and the staple detection unit 27 is mounted on the folding unit 20. Therefore, the folding unit 21 and the staple detection unit 27 are arranged closer to each other. can do. Thereby, after the staple ST on the paper is detected by the staple detection means 27, the distance for moving the paper toward the folding portion 21 can be made as short as possible. As a result, the bent portion and the position of the staple ST can be matched with high accuracy. Therefore, it is possible to create a booklet that has a better appearance and can be opened and closed smoothly.

  Further, the sheet post-processing apparatus 1 connected to the image forming apparatus 100 includes a staple processing unit 10 that drives the staple ST on the sheet, and a bending portion 21 is disposed on the downstream side of the staple processing unit 10 in the sheet conveyance direction. There are many. As described above, by separating the folding unit 20 having the bent portion 21 and the stapling unit 10, the configuration of the apparatus is easy, and the stapling process and the bi-folding process can be performed efficiently. However, on the other hand, there is also a problem that a deviation easily occurs between the bent portion and the position of the staple ST. For such a problem, in the paper post-processing apparatus 1 according to the present invention, the folding portion 21 is automatically arranged at the downstream side of the staple processing unit 10 in the paper conveyance direction, so that the folding position and the position of the staple ST are automatically matched. Therefore, it is possible to obtain the sheet post-processing apparatus 1 that can be folded accurately at a position where the staple ST exists while efficiently performing the stapling process and the bi-folding process.

  Next, the detailed configuration of the sheet post-processing apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a vertical sectional front view of the folding unit of the paper post-processing apparatus. The basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 6, and therefore the configuration common to the first embodiment is described in the drawings, and The description will be omitted.

  As shown in FIG. 7, the sheet post-processing apparatus according to the second embodiment includes a staple detection unit 27 in the folding unit 20 that is located on the upstream side of the folding unit 21 in the sheet conveyance direction, that is, on the sheet stacking unit 23. It is arranged so as to face the surface of the paper. And the staple detection means 27 is arrange | positioned with the predetermined distance X with respect to the position of the bending blade 29 of the bending part 21, like 1st Embodiment.

  Next, the operation of the bending unit 20 having the above configuration will be described with reference to FIGS. 9 to 11 with reference to FIG. FIG. 8 is a flowchart showing the operation of the sheet post-processing apparatus when the stapling process and the bi-folding process are performed with the center binding on the sheet that has been printed. FIG. 9 is a vertical sectional front view of the folding unit similar to FIG. 7 and shows the initial stage of entering the sheet bundle. FIG. 10 is a vertical sectional front view of the folding unit similar to FIG. FIG. 11 is a vertical sectional front view of a folding unit similar to FIG. 10 and shows a state in which the staple position is matched with the folding position.

  When printing is completed in the image forming apparatus 100, the process proceeds to step # 201 shown in FIG. 8, and the staple processing unit 10 (see FIG. 1) of the sheet post-processing apparatus 1 performs the stapling process at the center of the sheet bundle conveyance direction. The At this time, the stapling position is set at the center of the sheet conveyance direction based on the sheet size information received from the image forming apparatus 100. Thereafter, the sheet bundle is conveyed toward the folding unit 20.

  When the process proceeds to step # 202 in FIG. 8, in the folding unit 20, as shown in FIG. 9, the centering cursor 31 moves from the position of the folding blade 29 of the folding part 21 to a distance L that is ½ of the paper size. It moves toward the downstream side from the standby position. The moving distance of the center alignment cursor 31 is X + Y. As described above, the distance X is a distance between the staple detection means 27 and the position of the bending blade 29 of the bending portion 21, and the distance Y is an arbitrary distance.

  When the process proceeds to step # 203 in FIG. 8, the sheet bundle P is conveyed until it comes into contact with the center alignment cursor 31, as shown in FIG. The conveyance nip of the conveyance roller pair 24 is released immediately before the downstream end of the sheet bundle P contacts the center alignment cursor 31, and thereafter, the downstream end of the sheet bundle P is brought into contact with the center alignment cursor 31 by inertia.

  When the process proceeds to step # 204 in FIG. 8, the center alignment cursor 31 gradually moves toward the upstream in the center alignment unit 25. At this time, the sheet bundle P moves upstream together with the center alignment cursor 31, and the staple detection unit 27 starts detecting the staple ST on the sheet.

  In step # 205, it is determined whether the staple detection unit 27 has detected the staple ST on the paper. Then, the operations of step # 204 and step # 205 are repeated until the staple ST can be detected. During this time, the sheet bundle P is gradually moved upstream by the function of the center aligning unit 25, and the staple detection means 27 continues to detect the staple ST on the sheet bundle P.

  In step # 205, when the staple detection unit 27 detects the staple ST as shown in FIG. 10, the conveyance of the sheet bundle P is temporarily stopped, and the process proceeds to step # 206.

  When the process proceeds to step # 206 in FIG. 8, the sheet bundle P is moved by the predetermined distance X toward the upstream together with the center alignment cursor 31, as shown in FIG. As described above, the predetermined distance X is the distance between the staple detection means 27 and the position of the folding blade 29 of the folding portion 21, and therefore the detected position of the staple ST is the folding blade 29 of the folding portion 21. Matches the position of.

  In step # 207, the folding unit 21 performs a folding process on the sheet bundle P in half. The sheet bundle P, which has been folded in half and formed into a booklet, passes through the discharge unit 26 and is discharged to the booklet discharge tray 22 (see FIG. 1).

  In this way, even when the stapling detection means 27 is arranged on the downstream side of the folding unit 21 in the sheet conveying direction, the same operations and effects as those of the first embodiment when arranged on the upstream side can be obtained. That is, when the folding process is performed after the stapling process, the sheet can be accurately folded at the position where the stapling ST exists, and a booklet that can be easily opened and opened smoothly can be created. A high-performance sheet post-processing apparatus 1 can be provided.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the above embodiment, the stapling device 16 and the stapling detection means 27 are arranged in two places in the paper width direction. However, the number thereof is not limited to this, and three or more places are provided. It doesn't matter. Moreover, in the bending unit 20, the arrangement | positioning location of the staple detection means 27 is not necessarily limited to the location demonstrated by 1st and 2nd embodiment.

  The present invention can be used in a sheet post-processing apparatus including a folding unit that performs a folding process on a sheet.

1 is a schematic vertical sectional front view of a sheet post-processing apparatus according to a first embodiment of the present invention. FIG. 2 is a vertical sectional front view of a folding unit of the paper post-processing apparatus of FIG. 1. 3 is a flowchart illustrating an operation of the sheet post-processing apparatus of FIG. 1. FIG. 3 is a vertical sectional front view of a folding unit similar to FIG. 2 and shows an initial stage of entering a sheet bundle. FIG. 5 is a vertical sectional front view of the bending unit similar to FIG. 4 and shows a state in which staple detection means detects staples. FIG. 6 is a front view of a vertical section of the same folding unit as in FIG. 5, showing a state in which the stapling position matches the folding position. It is a vertical cross-sectional front view of the bending unit of the paper post-processing apparatus according to the second embodiment of the present invention. 6 is a flowchart illustrating an operation of the sheet post-processing apparatus. FIG. 8 is a vertical sectional front view of the same folding unit as in FIG. 7 and shows the initial stage of entry of a sheet bundle. FIG. 10 is a vertical sectional front view of a bending unit similar to FIG. 9 and shows a state in which staple detection means detects staples. FIG. 11 is a vertical cross-sectional front view of a folding unit similar to FIG. 10, showing a state in which the stapling position matches the folding position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper post-processing apparatus 10 Staple processing unit 16 Stapling apparatus 20 Bending unit 21 Bending part 23 Paper stacking part 24 Conveying roller pair 25 Center alignment part (paper conveying means)
27 Staple detection means 29 Bending blade 31 Center alignment cursor 100 Image forming apparatus X Predetermined distance P Sheet bundle ST Staple

Claims (4)

  A folding portion that folds the paper in a crease in the paper width direction perpendicular to the paper transport direction, a paper stacking portion that includes this folding portion at a substantially central position in the paper transport direction, and the paper on the paper stacking portion. A sheet conveying means for moving the sheet and a stapling detecting means arranged to face the surface of the sheet on the sheet stacking section and detecting the position of the staple driven into the sheet. When a staple is detected, the sheet post-processing apparatus moves the sheet toward the bent portion so that the staple position coincides with the bent portion by the sheet conveying unit.   The staple detection means is disposed at a predetermined distance in the paper conveyance direction with respect to the bent portion. When the staple detection means detects a staple on the paper, the paper conveyance means causes the paper to be moved by the predetermined distance. The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus moves toward the bent portion along the sheet conveyance direction.   The sheet post-processing apparatus according to claim 1, further comprising a folding unit configured around the folding unit, wherein the staple detection unit is mounted on the folding unit.   4. The paper according to claim 1, further comprising a stapling unit that drives staples on the paper, wherein the folding portion is disposed downstream of the stapling unit in the paper transport direction. 5. Post-processing device.

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