JP2013154981A - Sheet processing apparatus, image forming system, and sheet stacking method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a need of setting for each sheet size, to correspond to a nonstandard size, and to accurately control an overlapping amount of parts of sheets or sheet bundles without a need of a dedicated detecting means.SOLUTION: A sheet processing apparatus has: a center folding discharged paper sheet detecting sensor which is provided on an upstream side of a paper sheet discharging roller and which detects a discharged paper sheet bundle; and a conveying belt and a conveying roller which are provided at a saddle stitching stacking tray and which convey the paper sheet bundle received from the paper sheet discharging roller side to a downstream side. The sheet processing apparatus determines an operation start timing and an operation stop timing of the conveying roller based on detection results (T1, T2) of the center folding discharged paper sheet detecting sensor. The operation start timing is that before an anterior end of the paper sheet bundle reaches the conveying roller and after the conveying roller reaches a steady rotation speed (S103, 104), and the operation stop timing is that after a posterior end of the paper sheet bundle passes through the paper sheet discharging roller, a subsequent paper sheet bundle is conveyed, and an overlapping amount between a preceding paper sheet bundle and the subsequent paper sheet bundle, which is set in advance, is secured (S105, 106).

Description

  The present invention relates to a sheet processing apparatus for performing a predetermined process on a sheet-like recording medium (in the present specification, simply referred to as “sheet”) such as a loaded paper, recording paper, transfer paper, or OHP sheet. The present invention relates to an image forming system including a sheet processing apparatus and an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a digital multifunction peripheral, and a sheet stacking method executed by the sheet processing apparatus.

  Conventionally, a sheet processing apparatus for performing a center folding process for performing a folding process on a single sheet, or a saddle stitch bookbinding process for performing a folding process after aligning and binding a plurality of sheet bundles is provided for an image-formed sheet. Image forming systems have been widely used in recent years. Furthermore, the sheets (bundles) that have been subjected to the center folding process or the saddle stitching process are transported so that the folding portion is at the leading end in the transport direction, and sequentially transported with a part of the sheets (bundles) superimposed on the stacking tray. The sheet processing technology to perform is already known.

  As such a technique, for example, the inventions described in Patent Documents 1 and 2 are known. Among these, Patent Document 1 (Japanese Patent No. 4179011) discloses an image forming apparatus that is intended to orderly stack a bundle of sheets that are bundled and folded into two in a booklet tray regardless of the size of the sheets. A sheet receiving means for receiving sheets, a sheet bundling means for bundling sheets placed on the sheet receiving means, a sheet folding means for folding sheets bundled by the sheet bundling means, and a sheet folded by the sheet folding means are stacked. A sheet stacking unit, a transport roll member disposed above the sheet stacking unit and configured to transport a sheet folded by the sheet folding unit downward toward the sheet stacking unit, and a size of the sheet placed on the sheet receiving unit. Sheet size recognizing means for recognizing the sheet stacking means above the conveying roll member Each sheet by a step movement of each time the sheet conveying member is provided based on the recognition result by the sheet size recognizing means. A sheet processing apparatus is described in which an overlapping area of a predetermined length or more is set between sheets with the amount of movement of the sheet being variable.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-143777) solves problems such as bulging of a folded sheet bundle and an opening of a folded portion in an inclined sheet discharge tray, and appropriately sets a sheet bundle having poor conditions. In order to enable stacking, a paper stacking unit that stacks a stack of paper sheets in which a plurality of sheets are folded, and is inclined so that the downstream side in the paper transport direction is higher. The sheet stacking unit for stacking the folded sheet bundle, the sheet transporting unit for transporting the sheet stack stacked on the sheet stacking unit in the sheet transport direction, and the trailing end of the sheet bundle A sheet position detecting means for detecting that a predetermined standby position of the sheet placing portion has been reached, and a sheet bundle that is swingably or slidably disposed above the sheet placing portion and is stacked on the sheet placing portion. Paper pressing means comprising a paper contact portion that contacts the upper surface of the paper And a control means for controlling the paper transport means, the control means by the paper transport means when stacking the folded paper bundle to be transported on the paper stack stacked on the paper stacking unit. The folded sheet bundle loaded on the sheet loading section is conveyed in the sheet conveying direction, and it is detected that the rear end of the sheet bundle folded by the sheet position detecting means has reached a predetermined standby position. Thus, there is described a paper placing unit for stopping the paper conveying means.

  In Patent Document 1, in order to stack a sheet bundle in a saddle stitch stacking tray in an orderly manner regardless of the size of the sheet, a sheet (bundle) is partially conveyed on the stacking tray and sequentially conveyed by a sheet conveying member. A configuration is disclosed in which the conveyance amount of sequential conveyance by the sheet conveyance member is variable based on the size recognition result. However, in the invention described in the cited document 1, it is necessary to set the conveyance time for each sheet size in advance, the control becomes complicated, and it is difficult to deal with an irregular size sheet.

  Patent Document 2 discloses a configuration in which a detection unit is provided on a stacking tray, and when a trailing end of a sheet bundle is detected, a conveyance operation is sequentially stopped. However, since the detecting means is provided in the stacking tray, it is necessary to provide a dedicated detecting means, and during discharge from the saddle stitching unit, the sheet (bundle) is not grounded to the saddle stitching stacking tray, so that detection is possible. There is an unstable area.

In other words, conventionally, with regard to the operation of sequentially conveying a sheet or a bundle of sheets in a saddle stitching stacking tray,
-It is necessary to set the conveyance time for each sheet size in advance, and the control becomes complicated.
・ It is difficult to handle irregular sizes.
It is necessary to provide a dedicated detection means for detecting the sheet conveyance position on the saddle stitch stacking tray.
There were problems such as.

  Therefore, the problem to be solved by the present invention is that setting for each sheet size is unnecessary, it is possible to cope with an irregular size, and a sheet or a sheet bundle is accurately overlapped without requiring a dedicated detection means. The purpose is to be able to control the amount of overlapping.

  In order to solve the above-described problems, the present invention provides a folding unit that folds a sheet or a sheet bundle, a sheet discharging unit that discharges a sheet or a sheet bundle that is folded by the folding unit, and the sheet discharging unit. A sheet processing apparatus having a stacking unit that stacks the sheets or sheet bundles discharged by the detection unit, the detection unit being provided upstream of the sheet discharge unit and detecting the discharged sheets or sheet bundles And a conveying unit provided in the stacking unit and configured to convey a sheet or a sheet bundle received from the discharge unit side to the downstream side, and the operation of the conveying unit based on the detection result of the detecting unit It is characterized by determining a start timing and an operation stop timing.

  According to the present invention, it is not necessary to set for each sheet size, it is possible to cope with an irregular size, and the overlap amount for accurately overlapping a part of a sheet or a sheet bundle is controlled without requiring a dedicated detection means. can do.

1 is a system configuration diagram illustrating a system including a sheet post-processing apparatus and an image forming apparatus as a sheet processing apparatus according to an embodiment of the present invention. It is the schematic block diagram which looked at the end surface binding processing tray in FIG. 1 from the stacking surface side of the tray. It is a perspective view which shows schematic structure of the end surface binding processing tray in FIG. 1, and its attachment mechanism. It is a side view which shows operation | movement of the discharge | release belt in FIG. It is a perspective view which shows the moving mechanism of the stapler in FIG. It is a figure which shows the relationship between the sheet | seat stacked on the end surface binding process tray at the time of end surface binding, a reference fence, and an end surface binding stapler. It is sectional drawing which shows schematic structure of a saddle stitch stacking tray part. FIG. 8 is a perspective view of a saddle stitch stacking tray portion in FIG. 7. It is a perspective view which shows the internal structure of a saddle stitch stacking tray part. FIG. 6 is a diagram illustrating a state where a sheet stacking auxiliary unit is located at a use position and a state where the sheet stacking assist unit is located at a non-use position. 6 is a flowchart illustrating a control procedure for stacking a sheet bundle on a saddle stitch stacking tray. FIG. 10 is an operation explanatory diagram illustrating an operation when stacking a sheet bundle on a saddle stitch stacking tray. FIG. 6 is a diagram schematically illustrating a stacking state of sheet bundles on a saddle stitch stacking tray when it is determined that a full sensor is full. FIG. 6 is a diagram showing a comparison of the number of sheet bundles and the shape of sheet bundles. FIG. 10 is an operation explanatory view schematically showing an operation in which the saddle stitch stacking tray discharges a sheet bundle without limit. 3 is a block diagram illustrating a control configuration of an image forming system including a sheet post-processing apparatus PD and an image forming apparatus PR. FIG.

  The present invention is based on a signal from a paper detection means (a half-folded paper discharge detection sensor) in a saddle stitching unit provided upstream of the saddle stitching stacking tray, and is saddle-stitched by a transport means (transport belt and transport roller). It is characterized in that the operation start timing and the operation stop timing are determined when the sheet bundle is sequentially conveyed one by one on the stacking tray. Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are assigned to the same parts that can be regarded as the same or the same, and a duplicate description is omitted.

  FIG. 1 is a system configuration diagram showing a system including a sheet post-processing apparatus PD as a sheet processing apparatus according to an embodiment of the present invention and an image forming apparatus PR. In FIG. 1, an image forming apparatus PR converts an input image data (not shown) into image data that can be printed, and light that performs optical writing on a photoconductor based on an image signal output from the image processing circuit. Writing device, developing device for developing toner on latent image formed by optical writing on toner, transfer device for transferring toner image visualized by developing device to sheet, and fixing for fixing toner image transferred on sheet The sheet having at least the apparatus and having the toner image fixed thereon is sent to the sheet post-processing apparatus PD, and desired post-processing is performed by the sheet post-processing apparatus PD.

  Here, the image forming apparatus PR is of an electrophotographic system as described above, but any known image forming apparatus such as an ink jet system or a thermal transfer system can be used. In this embodiment, the image processing circuit, the optical writing device, the developing device, the transfer device, and the fixing device constitute image forming means.

  The sheet post-processing apparatus PD is attached to a side portion of the image forming apparatus PR, and the sheet discharged from the image forming apparatus PR is guided to the sheet post-processing apparatus PD. The sheet post-processing apparatus PD includes a conveyance path A, a conveyance path B, a conveyance path C, a conveyance path D, and a conveyance path H, and the sheet is a post-processing unit (in this embodiment) that performs post-processing on a single sheet. It is first transported to a transport path A having a punch unit 100) as a punching means.

  The conveyance path B is a conveyance path that passes through the conveyance path A and leads to the upper tray 201, and the conveyance path C is a conveyance path that leads to the shift tray 202. The conveyance path D is a conveyance path that leads to a processing tray F (hereinafter also referred to as “end face binding processing tray”) that performs alignment, stapling, and the like. The conveyance path A is distributed to the conveyance paths B, C, and D by the branch claw 15 and the branch claw 16, respectively.

  In this sheet post-processing apparatus, punching (punch unit 100), sheet alignment + edge binding (jogger fence 53, end surface binding stapler S1), sheet alignment + saddle stitching (saddle stitch upper jogger fence 250a, Each processing such as the saddle stitching lower jogger fence 250b, the saddle stitching stapler S2), the sheet sorting (shift tray 202), and the middle folding (folding plate 74, folding roller 81) can be performed. Therefore, the transport path A, the subsequent transport path B, the transport path C, and the transport path D are selected. Further, the conveyance path D includes a sheet storage portion E, and an end face binding processing tray F, a saddle stitching middle folding processing tray G, and a paper discharge conveyance path H are provided on the downstream side of the conveyance path D.

  In the conveyance path A common to the upstream of the conveyance path B, the conveyance path C, and the conveyance path D, an inlet sensor 301 that detects a sheet received from the image forming apparatus PR, an inlet roller 1, a punch unit 100, The punch and waste hopper 101, the conveying roller 2, the first and second branching claws 15, and the branching claws 16 are sequentially arranged. The first and second branch claws 15 and 16 are held in the state of FIG. 1 by a spring (not shown) (initial state), and the branch claws 15 and 16 are turned on by turning on the first and second solenoids (not shown). By changing the combination of the branching directions of the first and second branching claws 15 and 16 by selecting ON / OFF of the first and second solenoids, respectively. The sheet is distributed to the conveyance path D.

  When the sheet is guided to the conveyance path B, the state shown in FIG. 1, that is, the first solenoid remains OFF (the first branch claw 15 is in the initial state). As a result, the sheet is discharged from the conveying roller 3 to the upper tray 201 via the paper discharge roller 4.

  When the sheet is guided to the conveyance path C, the first and second solenoids are turned on from the state shown in FIG. 1 (the second branch claw 16 is in the initial state), so that the branch claw 15 branches upward. The nail | claw 16 will be in the state which each rotated below. Thus, the sheet is conveyed to the shift tray 202 side through the conveying roller 5 and the discharge roller pair 6 (6a, 6b). In this case, the sheets are sorted. Sheets are sorted by a shift tray paper discharge unit located at the most downstream portion of the sheet post-processing apparatus PD. Sheets are sorted by the shift paper discharge roller pair 6 (6a, 6b), the return roller 13, and the paper surface. The detection sensor 330, the shift tray 202, a shift mechanism (not shown) that reciprocates the shift tray 202 in a direction orthogonal to the sheet conveying direction, and a shift tray lifting mechanism that lifts and lowers the shift tray 202 are performed.

  When the sheet is guided to the conveyance path D, the branching claw 15 is moved upward by turning on the first solenoid that drives the first branching claw 15 and turning off the second solenoid that drives the second branching claw. Further, the branching claw 16 is rotated downward, and the sheet is guided from the conveying roller 2 to the conveying path D through the conveying roller 7. The sheet guided to the conveyance path D is guided to the end surface binding processing tray F, and the sheet subjected to alignment, stapling, and the like in the end surface binding processing tray F is guided to the shift tray 202 by the guide member 44. The sheet is fed to the saddle stitching / saddle folding processing tray G (hereinafter also simply referred to as “saddle stitching processing tray”). When guided to the shift tray 202, the sheet bundle is discharged from the discharge roller pair 6 to the shift tray 202. Further, the sheet bundle guided to the saddle stitching processing tray G side is folded and bound by the saddle stitching processing tray G, passes through the paper discharge conveyance path H, and is discharged from the paper discharge roller 83 to the saddle stitch stacking tray portion Z. Is done.

  On the other hand, a branching claw 17 is disposed in the conveyance path D, and is held in the state shown in the figure by a low load spring (not shown). After the trailing edge of the sheet conveyed by the conveyance roller 7 passes through the branching claw 17. At least the conveyance roller 9 among the conveyance rollers 9 and 10 and the staple paper discharge roller 11 can be reversed to reverse the sheet along the turn guide 8. As a result, the sheet is guided from the rear end of the sheet to the sheet storage portion E to stay (pre-stack), and can be conveyed while being overlapped with the next sheet. By repeating this operation, it is also possible to convey two or more sheets superimposed. Reference numeral 304 denotes a prestack sensor for setting a reverse feed timing when the sheets are prestacked.

  When the sheet is guided to the conveyance path D and sheet alignment and edge binding are performed, the sheets guided to the end surface binding processing tray F by the staple paper discharge roller 11 are sequentially stacked on the end surface binding processing tray F. In this case, alignment in the vertical direction (sheet conveyance direction) is performed by the tapping roller 12 for each sheet, and alignment in the horizontal direction (direction also orthogonal to the sheet conveyance direction—also referred to as sheet width direction) is performed by the jogger fence 53. The end-face stitching stapler S1 as the binding means is driven by a staple signal from a control device (not shown) between the end of the job, that is, from the last sheet of the sheet bundle to the first sheet of the next sheet bundle, and the binding process is performed. The sheet bundle that has been subjected to the binding process is immediately sent to the shift paper discharge roller 6 by the discharge belt 52 (see FIG. 2) on which the discharge claw 52a protrudes, and discharged to the shift tray 202 set at the receiving position. Is done.

  As shown in FIG. 1, the end-face stitching stapler S1 includes a stitcher (driver) S1a that strikes a staple, and a clincher S1b that bends the tip of the staple. Since the space portion S1c is formed, the end surface binding stapler S1 moves without interference between the end surface binding stapler S1 and the rear end reference fences 51a and 51b. Further, the end-face stitching stapler S1 is different from the saddle stitching stapler S2 in that the stitcher S1a and the clincher S1b are integrated. The stitcher S1a functions as a fixed side without moving in the direction perpendicular to the sheet surface, and functions as a moving side in which the clincher S1b moves in a direction perpendicular to the sheet surface. As a result, when the binding operation is performed on the sheet bundle SB, the clincher S1b moves to a stitcher S1a side in a predetermined binding portion of the sheet bundle SB that is in contact with the stack surfaces 51a1 and 51b1 of the rear end reference fence 51. In this process, a binding operation is performed.

  As shown in FIGS. 2 and 4, the discharge belt 52 is positioned at the center of alignment in the sheet width direction, is stretched between pulleys 62, and is driven by a discharge belt drive motor 157. A plurality of discharge rollers 56 are arranged symmetrically with respect to the discharge belt 52, are provided so as to be rotatable with respect to the drive shaft, and function as driven rollers.

  The release claw 52 a is configured such that the home position is detected by a release belt HP sensor 311, and this release belt HP sensor 311 is turned on / off by a discharge claw 52 a provided on the discharge belt 52. Two discharge claws 52a are arranged at opposing positions on the outer periphery of the discharge belt 52, and the sheet bundle stored in the end face binding processing tray F is moved and conveyed alternately. Further, if necessary, the discharge belt 52 is rotated in the reverse direction, and the discharge claw 52a waiting to move the sheet bundle from now on and the back side of the discharge claw 52a on the opposite side of the sheet bundle accommodated in the end face binding processing tray F It is also possible to align the tips in the transport direction.

  In FIG. 1, reference numeral 110 denotes a rear end pressing lever, which is positioned at the lower end portion of the rear end reference fence 51 so that the rear end of the sheet bundle SB accommodated in the rear end reference fence 51 can be pressed. It reciprocates in a direction substantially perpendicular to the end face binding processing tray F. Sheets discharged to the end surface binding processing tray F are tapped for each sheet and aligned in the vertical direction (sheet conveying direction) with the rollers 12, but the trailing edge of the sheets stacked on the end surface binding processing tray F is curled. When the waist is weak, the rear end tends to buckle and swell due to the weight of the seat itself. Further, as the number of stacked sheets increases, the gap for the next sheet in the rear end reference fence 51 is reduced, and the vertical alignment tends to be deteriorated. Therefore, the trailing edge pressing mechanism 110 reduces the swelling of the trailing edge of the sheet so that the sheet can easily enter the trailing edge reference fence 51, and the trailing edge pressing lever 110 directly presses the sheet.

  In FIG. 1, reference numerals 302, 303, 304, 305, and 310 denote sheet detection sensors that detect whether or not a sheet has passed at a provided position or whether or not a sheet is stacked.

  FIG. 2 is a schematic configuration diagram of the end face binding processing tray F as viewed from the tray stacking surface side, and corresponds to the case of viewing from the right side surface of FIG. In the drawing, the alignment in the width direction of the sheet received from the upstream image forming apparatus PR is performed by jogger fences 53a and 53b, and the vertical direction is the first and second rear end reference fences 51a and 51b (in FIG. 1). (Matched by reference numeral 51). FIG. 6 is a diagram showing the relationship among the sheets stacked on the end surface binding processing tray F at the time of end surface binding, the rear end reference fences 51a and 51b, and the end surface binding stapler S1. As can be seen from the figure, the first and second rear end reference fences 51a and 51b are respectively provided with stack surfaces 51a1, 51a2, 51b1 and 51b2 to which the sheet rear end ST abuts and is held on the inner side. The end ST is supported. As can be seen from FIG. 2, the support is possible at four points. However, in the case of one-face oblique binding, the end-face stitching stapler S1 moves to the end portion of the stacked sheet bundle SB, and the binding process is performed at an oblique angle. I do. FIG. 6B shows the relationship between the staple needle S1c after binding and the rear end fence 51b. At that time, as shown in FIG. 6A, the sheet bundle SB is stacked in contact with any two of the stack surfaces 51a1, 51a2, and 51b1 of the rear end fence 51. This is because of mechanical errors including the accuracy of attaching the rear end fences 51a and 51b, and is supported in a stable state by being supported at two points.

  After completion of the alignment operation, binding processing is performed by the end surface binding stapler S1, and the discharge belt 52 is driven counterclockwise by the discharge belt drive motor 157, as can be seen from the perspective view showing the operation of the discharge belt in FIG. The sheet bundle after the binding process is scooped by the discharge claw 52a attached to the discharge belt 52 and discharged from the end face binding processing tray F. Reference numerals 64a and 64b are a front side plate and a rear side plate. Further, this operation can be performed in the case of an unbound bundle that is not subjected to the binding process after the alignment process.

FIG. 3 is a perspective view showing a schematic configuration of the end face binding processing tray F and its attached mechanism. As shown in the figure, the sheets guided to the end-face binding processing tray F by the staple paper discharge roller 11 are sequentially stacked on the end-face binding processing tray F. At this time, when the number of sheets discharged to the end face binding processing tray F is one sheet, the sheet is aligned in the vertical direction (sheet conveying direction) with the tapping roller 12 for each sheet, and the jogger fences 53a and 53b perform the width direction ( Alignment in the sheet width direction perpendicular to the sheet conveyance direction is performed. The hitting roller 12 is given a pendulum motion by the hitting SOL 170 about the fulcrum 12a and intermittently acts on the sheet fed to the end face binding processing tray F to abut the sheet rear end ST against the rear end reference fence 51. The hitting roller 12 itself rotates counterclockwise. The jogger fence 53 is provided with a pair of front and rear (53a, 53b) as shown in FIGS. 2 and 3, and is driven through a timing belt by a jogger motor 158 capable of forward and reverse rotation, and reciprocates in the sheet width direction.

  FIG. 5 is a side view showing the stapler width direction moving mechanism. As shown in FIG. 5, the end-face stitching stapler S1 is driven through a timing belt 159a by a forward / reversely movable stapler moving motor 159, and moves in the sheet width direction in order to bind a predetermined position at the rear end of the sheet. A stapler movement HP sensor 312 that detects the home position of the end-face stitching stapler S1 is provided at one end of the movement range, and the binding position in the sheet width direction is the movement of the end-face stitching stapler S1 from the home position. Controlled by quantity. The end-face stitching stapler S1 is configured so that it can be bound at one or a plurality of positions (generally two places) at the sheet rear end, and at least over the entire width of the sheet rear end ST supported by the rear end reference fences 51a and 51b. It is movable. Further, it is possible to move to the front side of the apparatus as much as possible for exchanging the staples, so that the user can exchange the staples.

  A sheet bundle deflection mechanism I is provided on the downstream side in the sheet conveying direction of the end-face binding processing tray F. As shown in FIG. 1, a conveyance path for feeding the sheet bundle SB from the end face binding processing tray F to the saddle stitching processing tray G, and from the end face binding processing tray F to the shift tray 202, and a conveyance means for conveying the sheet bundle SB are: A conveyance mechanism 35 that applies a conveyance force to the bundle SB, a discharge roller 56 that turns the sheet bundle SB, and a guide member 44 that performs a guide for turning the sheet bundle SB.

  Each detailed configuration will be described. The driving force of the driving shaft 37 is transmitted to the roller 36 of the transport mechanism 35 by a timing belt. The roller 36 and the driving shaft 37 are connected and supported by an arm, and driven. The shaft 37 can be swung about the rotation fulcrum. The roller 36 of the transport mechanism 35 is driven to swing by a cam 40. The cam 40 rotates around a rotation shaft and is driven by a motor (not shown). In the transport mechanism 35, a driven roller 42 is disposed at a position opposite to the roller 36, and a sheet bundle is sandwiched between the driven roller 42 and the roller 36 and pressed by an elastic material to give a transport force.

  A conveyance path for turning the sheet bundle from the end face binding processing tray F to the saddle stitching processing tray G is formed between the discharge roller 56 and the inner surface of the guide member 44 on the side facing the discharge roller 56. The guide member 44 rotates around a fulcrum, and the drive is transmitted from the bundle branch drive motor 161 (see FIG. 2). When the sheet bundle is conveyed from the end surface binding processing tray F to the shift tray 202, the guide member 44 rotates in the illustrated clockwise direction around the fulcrum, and the outer surface of the guide member 44 (the surface not facing the discharge roller 56). ) And the outer guide plate function as a conveyance path. When the sheet bundle P is sent from the end surface binding processing tray F to the saddle stitching processing tray G, the rear end of the sheet bundle SB aligned in the end surface binding processing tray F is pushed up by the discharge claw 52a, and the roller 36 of the transport mechanism 35 and the roller 36 A sheet bundle is sandwiched between the opposed driven rollers 42 facing each other, and a conveying force is applied. At this time, the roller 36 of the transport mechanism 35 stands by at a position where it does not hit the leading end of the sheet bundle SB. Next, after the leading edge of the sheet bundle SB passes, the roller 36 of the transport mechanism 35 is brought into contact with the sheet surface to apply a transport force. At this time, the guide member 44 and the discharge roller 56 form a guide for the turn conveyance path, and convey the sheet bundle SB to the downstream saddle stitching processing tray G.

  As shown in FIG. 1, the saddle stitch processing tray G is provided on the downstream side of the sheet bundle deflection mechanism including the conveyance mechanism 35, the guide member 44, and the discharge roller 56. The saddle stitching processing tray G is provided substantially perpendicularly on the downstream side of the sheet bundle deflection mechanism, with the center folding mechanism at the center, the bundle conveyance guide plate upper 92 above, and the bundle conveyance guide below. A lower plate 91 is arranged.

Further, an upper bundle conveying roller 71 is provided above the upper bundle conveying guide plate 92, and a lower bundle conveying roller 72 is provided below the upper bundle conveying guide plate 92. A saddle stitch upper jogger fence 250a is arranged on both sides along the side surface of 92. Similarly, a saddle stitch lower jogger fence 250b is provided on both sides along the side surface of the bundle conveyance guide plate lower 91, and the saddle stitch stapler S2 is disposed at a place where the saddle stitch lower jogger fence 250b is installed. The saddle stitching upper jogger fence 250a and the saddle stitching lower jogger fence 250b are driven by a driving mechanism (not shown) and perform an alignment operation in a direction orthogonal to the sheet conveying direction (sheet width direction). The saddle stitch stapler S2 is a pair of a clincher portion and a driver portion, and two pairs are provided at a predetermined interval in the sheet width direction.

  In addition, a movable rear end reference fence 73 is disposed so as to cross the bundle conveyance guide plate lower 91, and can be moved in the sheet conveyance direction (vertical direction in the drawing) by a moving mechanism including a timing belt and its driving mechanism. Yes. As shown in FIG. 1, the drive mechanism includes a drive pulley and a driven pulley on which the timing belt is stretched, and a stepping motor that drives the drive pulley. Similarly, a rear end tapping claw 251 and its drive mechanism are provided on the upper end side of the upper bundle transport guide plate 92. The trailing edge tapping claw 251 can reciprocate in a direction away from the sheet bundle deflecting mechanism and a direction pushing the trailing edge of the sheet bundle (the side that contacts the trailing edge when the sheet bundle is introduced) by a timing belt 252 and a driving mechanism (not shown). ing.

  The center folding mechanism is provided at a substantially central portion of the saddle stitching processing tray G, and includes a folding plate 74, a folding roller 81, and a conveyance path H that conveys the folded sheet bundle. In FIG. 1, reference numeral 326 denotes a home position sensor for detecting the home position of the rear end tapping claw 251, reference numeral 323 denotes a half-folded sheet discharge detection sensor for detecting a half-folded sheet, and reference numeral 321 denotes a sheet. A bundle detection sensor 322, which detects that the bundle has reached the center folding position, is a movable rear end reference fence home position sensor that detects the home position of the movable rear end reference fence 73.

  After performing a half-folding process on a single sheet or a saddle-stitching process on a plurality of sheet bundles, the sheet is discharged to a saddle-stitch stacking tray Z. Details of the saddle stitch stacking tray will be described later.

  Since the saddle stitching operation is a known technique as disclosed in, for example, Japanese Patent Application Laid-Open No. 2006-143466, detailed description thereof is omitted here.

  7 is a cross-sectional view showing a schematic configuration of the saddle stitching stacking tray section, FIG. 8 is a perspective view of the saddle stitching stacking tray section in FIG. 7, and FIG. 9 is a perspective view showing an internal structure of the saddle stitching stacking tray section.

  7 and 8, the saddle stitch stacking tray section Z includes a sheet stacking section 401, a sheet stacking auxiliary section 402, a transport roller 406, a transport belt 407, a transport belt driving roller 403, and transport belt driven rollers 404 and 405. Yes.

  The sheet stacking unit 401 includes an inclined surface 401a and a substantially horizontal surface 401b provided along the sheet discharge direction, and a curved surface 401c provided between the inclined surface 401a and the approximately horizontal surface 401b. The inclined surface 401a, the curved surface 401c, and the substantially horizontal surface 401b constitute one continuous stacking surface (sheet stacking surface). The inclined surface 401a is inclined with the sheet discharge port side (the discharge roller 83 side) facing downward, and the length of the substantially horizontal surface 401b in the sheet discharge direction is set to be longer than the same length of the inclined surface 401a.

  On the surface of the sheet stacking unit 401, a conveyance belt 407 as a sheet conveyance unit is formed along a stacking surface including an inclined surface 401a, a curved surface 401c, and a substantially horizontal surface 401b by a conveyance belt driving roller 403 and conveyance belt driven rollers 404 and 405. is set up. It is desirable to use a material made of a material such as chloros-type polyethylene having a large friction as the conveyor belt 407. As shown in FIG. 9, the conveyor belt drive roller 403 and the conveyor belt driven rollers 404 and 405 are rotatably supported coaxially on the drive shaft 419 and the driven shafts 420 and 421, respectively.

  The endless transport belt 407 is wound around the transport belt driving roller 403 and the transport belt driven rollers 404 and 405 in a state where a predetermined tension is applied, and is rotationally driven by the driving force applied to the drive shaft 419. The belt width of the conveying belt 407 is approximately 40 mm. A pair of conveying belts 407 are provided, and the distance between the pair of belts is set within a range within a B5SEF width that the sheet post-processing apparatus PD according to the present embodiment can perform the saddle stitching process. In this embodiment, the two conveying belts 407 are wound around the rollers 403, 404, and 405. However, three or more belts or one wide belt may be used. The rollers 403, 404, and 405 are appropriately provided according to the number of conveying belts.

  On the inclined surface 401 a of the sheet stacking unit 401, a transport driving roller 406 that abuts on the upper surface of the stacked sheets (bundle) and applies a transport force, and a transport driven roller 411 is provided on the opposite side of the transport drive roller 406. ing. The conveyance driving roller 406 and the conveyance driven roller 411 provide a conveyance force sufficient for the sheet (bundle) to rise up the inclined surface 401a, and at the same time prevent the sheet (bundle) from sliding down the inclined surface 401a. A material having a large friction coefficient, such as EP rubber, is suitable for the transport driving roller 406. By using such a material, a transport force can be reliably applied to the sheets (bundles). The same is true for the transport driven roller 411.

  Further, the transport driving roller 406 is swingably supported by the stacking tray receiving guide member 408, and an elastic force is applied to the transport driven roller 411 by an elastic force applying member 409 such as a compression spring or a coil spring. Has been. When the sheet (bundle) is discharged from the discharge roller 83, the sheet (bundle) is usually guided to the nip between the transfer driving roller 406 and the driven roller 411, and at the same time, a transfer force is applied from the transfer belt 407.

  As shown in FIG. 9, the conveyance belt drive roller 403 and the conveyance drive roller 406 have opposite rotation directions, but need to rotate at the same speed on the roller peripheral surface. Therefore, the drive is transmitted from the same drive source (stack motor) 412 through speed reduction mechanism elements 413, 414, 415, 416, 417, and 418 constituted by gears, timing pulleys, timing belts and the like. If the stacking motor 412 uses, for example, a stepping motor or a DC brushless motor with an encoder capable of detecting the amount of rotation, it is not necessary to provide a separate sensor, and a simple configuration can be achieved. The driving force from the driving source 412 transmitted to the transport driving roller driving shaft 422 is further transmitted to the shaft 422c via the timing pulley 422a and the timing belt 422b, and the transport driving roller 406 is transmitted to the shaft 422c. Driven by driving force.

  In the present embodiment, in the regions of the inclined surface 401a and the curved surface 401c, by sequentially conveying a part of the sheets (bundles) in a superimposed state, the subsequent sheets ( Consideration is made to prevent the folded portion that is the tip of the bundle from entering. Details of the operation will be described later.

  The sheet stacking auxiliary unit 402 is provided on the downstream side of the sheet stacking unit 401 and includes an inclined surface (sheet stacking auxiliary surface 402 a) whose upstream side in the transport direction is upward with respect to the substantially horizontal part 401 b of the sheet stacking unit 401. The sheet stacking auxiliary surface 402a is a leading sheet that prevents a sheet (bundle) from dropping when a large number of sheets (bundle) are sequentially transported by the transport roller 406 and the transport belt 407 and stacked on the sheet stacking unit 401. It has a function of regulating the position of the sheet (bundle).

  Since the sheet stacking assisting unit 402 may be used or not used, the sheet stacking assisting unit 402 can be stored or stored below the sheet stacking unit 401 when not used. FIG. 10 is a diagram illustrating a state where the sheet stacking assisting unit is located at the use position and a state where the sheet stacking assisting unit is located at the non-use position. FIG. 10A illustrates the position in the use state, and FIG. The position of the non-use state is shown respectively. As shown in FIG. 10B, the sheet stacking auxiliary unit 402 can be stored below the sheet stacking unit 401 from the use state of FIG. 10A, and further to a user who outputs a large number of sheets (bundles). The paper can be discharged without limit.

  Hereinafter, a specific operation of the saddle stitch stacking tray unit will be described.

  FIG. 11 is a flowchart showing a control procedure for stacking a sheet bundle on the saddle stitch stacking tray, and FIG. 12 is an operation explanatory diagram showing an operation when stacking the sheet bundle on the saddle stitch stacking tray.

  When a sheet or a sheet bundle (hereinafter, a sheet bundle is taken as an example) is discharged to the saddle stitch stacking tray Z, first, the sheet post-processing apparatus PD performs the middle folding process to the sheet bundle PB with the saddle stitching middle folding processing tray G. The sheet bundle PB reaches the half-folded sheet discharge detection sensor 323 (FIG. 12A). In general, in the middle folding and saddle stitching process, an additional folding process (not shown) is performed after the process to reduce the folding height. Therefore, after the sheet bundle PB has passed through the middle folding roller 81, Before reaching or after reaching the folded paper discharge detection sensor 323, it temporarily stops before reaching the paper discharge roller 83.

  The half-fold paper discharge detection sensor 323 is a reflection type photosensor that irradiates light toward the conveyance path of the sheet bundle PB and detects the front and rear ends of the sheet bundle PB with or without reflected light. It is disposed between the roller 81 and the paper discharge roller 83. The half-fold paper discharge detection sensor 323 also has a function of determining the timing of the half-fold processing and detecting an abnormality when a sheet jam occurs due to some error. In determining the timing of the middle folding process, for example, it is used for determining the driving timing of the roller in the case of the additional folding process, the timing of retreating the sheet bundle PB, and the like.

  When the middle folding process is normally completed and the sheet bundle PB is discharged, the process proceeds to the middle folding / saddle stitching stacking control shown in FIG. In this control, first, the full detection detection of the saddle stitch stacking tray Z is performed by the full detection filler 410 and a filler position sensor (not shown) (step S101). The filler position sensor is a sensor configured to optically detect the position of the end of the filler opposite to the sheet contact side and detect that the filler is full from the position. Sensor. When it is determined from the position of the full filler 410 that the sheet bundle PB stacked in the sheet stacking unit 401 is full, a signal is sent to a CPU_PD1 (see FIG. 16) described later, and the saddle stitch stacking tray Z The process proceeds to a full process so as not to accept the sheet bundle (step S108). In addition to detecting using the filler position sensor for full detection, for example, a long-distance reflection type sensor may be used to detect the leading edge where the sheet bundle PB is stacked and rises.

  When the saddle stitch stacking tray Z can receive the sheet bundle PB (step S102), a signal indicating that the center folded paper discharge detection sensor (discharge sensor in the figure) 323 detects the leading end PBs of the sheet bundle PB is used as a starting point ( As T1), after the leading edge is detected, the process waits for the discharge motor that drives the discharge roller 83 to rotate for a preset number of A pulses (2376 plus), that is, waits for the wait rotation amount to elapse (step S103). ), A command is sent to the stacking motor 412 to start the operation of the transport belt 407 and the transport drive roller 406 (step S104: FIG. 12B). In the present embodiment, the half-fold discharge detection sensor 323 serves as a discharge sensor that detects a sheet or a sheet bundle PB discharged from the saddle stitching / folding tray G to the saddle stitch stacking tray Z. It also functions as an entrance sensor for sheets or sheet bundles entering the stacking tray Z.

  In the present embodiment, the trigger is when the half-fold paper discharge detection sensor 323 detects the leading edge of the sheet bundle PB, and after waiting for the paper discharge roller to rotate by the number of A pulses (for example, 2376 pulses), the trigger is It is also possible to use another signal from the sheet post-processing apparatus PD. Further, the wait rotation amount of the stacking motor 412 to be described later may be a rotation amount that reaches the steady rotation when the sheet bundle PB enters the conveyance driving roller 406 of the saddle stitch stacking tray Z. At this time, the outer peripheral moving speed of the conveying belt 407 and the conveying driving roller 406 is set to be about 0.3% slower than the outer peripheral moving speed of the paper discharge roller 83, so that the conveying belt 407 and the conveying driving roller 406 located downstream. This prevents the sheet bundle PB from being pulled. This prevention of tension is because when the tension is generated by the downstream conveyance, the sheet bundle PB slips at the upstream sheet discharge roller 83 and slip marks are generated. When slip marks occur, the image quality naturally deteriorates. In addition, an overload is applied to the downstream conveying belt 407 and the conveying drive roller 406, leading to wasteful energy consumption.

  Subsequently, a detection signal of the trailing end of the sheet bundle PB detected by the half-folded sheet discharge detection sensor (discharge sensor in the figure) 323 is set as a starting point (T2: FIG. 12C), and after the trailing end is detected, the conveyance belt 407 is detected. After waiting for the conveyance drive roller 406 to rotate for a preset number of B pulses (for example, 1803 plus) (step S105), a command is sent to the stacking motor 412 to stop the operations of the conveyance belt 407 and the conveyance drive roller 406. (Step S106: FIG. 12D). In this embodiment, the wait rotation amount is set after waiting for the conveyance belt 407 and the conveyance drive roller 406 to rotate by the number of B pulses (for example, 1803 plus), but the overlapping amount of arbitrary sheet bundles PB in conveyance is sequentially set. You can set it to the value you want. Note that the A and B pulse numbers of the A pulse number and the B pulse number are appropriately set according to the overlap amount.

  FIG. 12E is a schematic diagram illustrating a state when the second sheet bundle PB is sequentially conveyed and stopped. The subsequent sheet bundle PB2 is sequentially conveyed to the preceding sheet bundle PB1 with a predetermined overlap amount PBx. The existence of such an overlapping amount PBx can prevent the folded portion PB2a, which is the leading end of the succeeding sheet bundle PB2, from entering the opening PB1a, which is the trailing end of the preceding sheet bundle PB1. Thereafter, the conveyance is sequentially repeated based on the processing procedure of the flowchart of FIG. That is, by performing the processing as described above, the conveyance amount and the conveyance stop of the sheet bundle PB are repeated, so that the trailing end portion of the preceding sheet bundle PB and the leading end portion of the following sheet bundle PB are set in a predetermined overlap amount. It is possible to superimpose, sequentially convey and stack with PBx.

  FIG. 13 is a diagram schematically showing a loaded state when it is determined that the full sensor is full. When the sheet bundle PB that is sequentially conveyed reaches the sheet stacking assisting surface 402a of the sheet stacking assisting section 402, the sheet bundle PB is prevented from dropping and the position of the leading sheet bundle PB1 is restricted, and therefore is transported further. Never happen. Subsequent sheet bundles PB2 to Pn2 (n: positive integer) are sequentially overlapped with the leading sheet bundle PB1 in contact with the sheet stacking auxiliary surface 402a. Since the center-fold / saddle-stitched sheet bundle PB has a bulge on the folding side, the stacked sheet bundle PB stands up as the opening is clogged, and is stacked up to a point where fullness detection works.

  FIG. 14 is a diagram comparing the number of sheet bundles PB and the shape of the sheet bundle. As shown in FIG. 14A, the sheet bundle PB has a small booklet thickness in the case of a single half-fold or a small number of saddle-stitched bundles PBn as shown in FIG. 14A, whereas as shown in FIG. In the saddle stitching bundle PBm, the booklet thickness is large, and the paper thickness of the folded portion is accumulated and the inner sheet sticks out of the opening portion.

  In contrast to the sheet bundle PB having such a shape, in the present embodiment, the front end PBs and the rear end of the sheet bundle PB include the accumulation of the paper thickness of the folded portion PBf and the protrusion of the inner sheet Pi of the opening PBg. Since PBt is detected and controlled, the same control is possible regardless of the number of sheets to be bound. Further, the same overlap amount is set regardless of the sheet size, and the control can be performed with a simple control configuration.

  When a series of jobs are completed, the half-fold / saddle stitching stacking control is completed, or when full detection is activated, the process proceeds to full processing.

  Further, as shown in FIG. 10, the sheet stacking auxiliary unit 402 can be stored below the sheet stacking unit 401. By storing the sheet stacking auxiliary unit 402 below the sheet stacking unit 401, the sheet stacking assisting unit 402 becomes the head as illustrated in FIG. Since the sheet stacking auxiliary surface 402a for regulating the position of the sheet bundle PB1 is eliminated, it is possible to perform limitless sheet discharge in which sheets are discharged continuously. The fact that limitless paper discharge is possible is a very preferable function for a user who outputs a large number of sheet bundles PB. In the limitless discharge, the subsequent sheet bundle PB is continuously sent downstream by the conveying belt 407 without being full.

  FIG. 15 is an operation explanatory view schematically showing the operation of the saddle stitch stacking tray to discharge the sheet bundle without limit.

  Similar to the case of stacking using the sheet stacking auxiliary unit 402 shown in FIG. 12, the limitless discharge is controlled by the CPU_PD1 of the sheet post-processing apparatus PD. This control procedure is also executed in the same procedure as the flowchart shown in FIG.

  However, in FIG. 12, the sheet stacking assisting unit 402 is stored below the sheet placing unit 401 as shown in FIG. 10B, and there is a member on which the sheet is placed on the downstream side of the sheet placing unit 401. It ’s gone. As shown in FIG. 15, instead of the sheet stacking auxiliary unit 402, a stacking box 430 for stacking the sheet bundle PB is disposed below the transport belt driving roller 403 on the most downstream side in the sheet transport direction of the sheet placing unit 401. It is installed with the upper part opened.

  On the other hand, the subsequent sheet bundle PB is further conveyed from the state shown in FIG. 12E in the sheet bundle PB, and the leading edge of the succeeding sheet bundle PB overlaps the rear end of the preceding sheet bundle PB with the aforementioned overlap amount PBx. As shown in FIGS. 15A and 15B, the sheet is sequentially conveyed by the conveyor belt 407. At that time, as shown in FIG. 15B, the sheet bundle PB that is sequentially conveyed is not restricted by the sheet stacking auxiliary surface 402a, and therefore, as the subsequent sheet bundle PB is sequentially conveyed, the preceding sheet bundle PB is changed to FIG. As shown in (c), they are sequentially dropped into the loading box 300 and stored.

  If the stacking box 300 is appropriately replaced, it is possible to discharge the sheet without limit without stopping the image forming operation of the image forming apparatus PR.

  In this embodiment, the sheet stacking assisting unit 402 can be stored below the sheet placing unit 401. However, the sheet stacking assisting unit 402 can be removed and can be removed only when processing without limit. You can also However, in that case, it is necessary to prevent loss and secure a separate storage location. Therefore, as in the present embodiment, the sheet stacking auxiliary tray 402 is attached to the saddle stitch stacking tray section Z, and the limitless switching is performed. Is more desirable.

  The control described so far is executed by the control circuit of the sheet post-processing apparatus PD. FIG. 16 is a block diagram illustrating a control configuration of an image forming system including the sheet post-processing apparatus PD and the image forming apparatus PR. The sheet post-processing device PD includes a control circuit equipped with a microcomputer having a CPU_PD1, an I / O interface PD2, and the like. The CPU_PD1 includes a CPU of the image forming apparatus PR, each switch of the operation panel PR1, and each sensor (not shown). Is input via the communication interface PR2, and the CPU_PD1 executes predetermined control based on the input signal. Further, the CPU_PD 1 controls driving of the solenoid and the motor via the driver and the motor driver, and acquires sensor information in the apparatus from other interfaces.

  In addition, motor drive control is performed by the motor driver via the I / 0 interface PD2 in accordance with the control target and sensor, and sensor information is acquired from the sensor. The control is based on a program defined by the program code while the CPU 101 reads a program code stored in a ROM (not shown), expands it in a RAM (not shown), and uses the RAM as a work area and a data buffer. Executed.

  Also, the control of the sheet post-processing apparatus PD in FIG. 16 is executed based on an instruction or information from the CPU of the image forming apparatus PR. The user's operation instruction is issued from the operation panel PR1 of the image forming apparatus PR, and the image forming apparatus PR and the operation panel PR1 are connected to each other via a communication interface PR3. As a result, the operation signal from the operation panel PR1 is transmitted from the image forming apparatus PR to the sheet post-processing apparatus PD, and the processing state and functions of the sheet post-processing apparatus PD are transmitted to the user or the operator via the operation panel PR1. Be notified.

As described above, according to the present embodiment,
1) A conveyor belt 407 provided on the saddle stitching stacking tray Z on the basis of the detection timing of a half-fold paper discharge detection sensor 323 provided between the folding roller 81 and the paper discharge roller 83 in the paper discharge conveyance path H; Since the operation start timing and operation stop timing of the stacking motor 412 that drives the conveying roller 406 are determined, setting for each sheet size is not required, it is possible to cope with an irregular size, and no dedicated detection means is required. In addition, a large amount of saddle stitching can be realized while maintaining a good stacking state.
2) The operation start timing of the stacking motor 412 is set before the leading edge of the sheet bundle reaches the conveying roller 406 and after the conveying roller 406 reaches a steady rotational speed. Thereby, when the sheet bundle reaches the conveyance roller 406, the conveyance roller 406 is shifted to the steady rotation, so there is no possibility that the conveyance failure of the sheet bundle occurs.
3) The operation start timing of the stacking motor 412 is such that the trailing end of the preceding sheet bundle passes through the sheet discharge roller 83, the succeeding sheet bundle is conveyed, and a preset overlap amount PBx is set between the preceding sheet bundle. It is set after securing. As a result, the subsequent sheet bundle is sequentially conveyed in a state having an overlap area with the preceding sheet bundle, and the folded portion PBf which is the leading end of the subsequent sheet bundle enters the opening PBg which is the rear end of the preceding sheet bundle. Can be prevented.
4) Since the conveyance speed of the conveyance belt 407 and the conveyance roller 406 is lower than the conveyance speed of the paper discharge roller 83, it is possible to prevent the sheet bundle from being pulled. As a result, it is possible to prevent image quality degradation and useless energy consumption.
5) Since the conveyance belt 407 and the conveyance roller 406 are driven by the same drive source (stacking motor 412), it is possible to perform reliable sheet conveyance on the inclined surface 401a and the substantially horizontal surface 401b. Moreover, since there is one drive source, it can be configured at low cost.
6) Since the sheet stacking assisting unit 402 having the sheet stacking assisting surface 402a taking two positions of the sheet stacking position and the retracted position retracted from the sheet stacking position is provided on the downstream side of the sheet stacking surface 401, the sheet stacking unit 402 is provided. At the position, the sheet bundle PB is prevented from dropping, the position of the leading sheet bundle PB is regulated, and at the retracted position, limitless discharge can be performed toward a user who outputs a large number of sheet bundles PB. .
7) Sheet bundles can be stacked on the saddle stitch stacking tray Z, or a stacking box 300 can be dropped from the saddle stitch stacking tray Z to stack a large number of sheet bundles. The sheet bundle PB can be stacked without causing an increase in size. At that time, the stacking surface of the saddle stitch stacking tray Z can be a horizontal surface that is easy to take out the output and has a good stacking state, and can be configured like a user.
There are effects such as.

  In the claims, the sheet bundle is denoted by PB, the folding means is the folding plate 74 and the folding roller 81, the discharging means is the discharging roller 83, and the stacking means is the saddle stitch stacking tray Z or the sheet stacking unit 401. In addition, the detection means is the half-folded paper discharge detection sensor 323, the conveyance means is the conveyance roller 406, the front end of the sheet bundle is denoted by PBs, the rear end of the sheet bundle is denoted by PBt, the overlap amount is PBx, and the inclined surface is Reference numeral 401a, curved surface 401c, substantially horizontal plane 401b, conveyance belt 407, conveyance roller 406, drive source 4106, sheet stacking assist unit 402, sheet processing The apparatus corresponds to the sheet post-processing apparatus PD, and the image forming system corresponds to a system including the sheet post-processing apparatus PD and the image forming apparatus PR.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and all the technical matters included in the technical idea described in the claims are all included. The subject of the present invention. The above embodiment shows a preferable example, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the content disclosed in this specification, These are included in the technical scope described in the appended claims.

74 Folding plate 81 Folding roller 83 Paper discharge roller 323 Middle folding paper discharge detection sensor 401 Sheet stacking portion 401a Inclined surface 401b Substantially horizontal surface 401c Curved surface 402 Sheet stacking assisting portion 402a Sheet stacking assisting surface 406 Transporting roller 407 Conveying belt 412 Stacking motor PB Sheet Bundle PBs Sheet bundle leading edge PBt Sheet bundle trailing edge PBx Overlap amount PD Sheet post-processing device (sheet processing device)
PR Image forming device Z Saddle stitch stacking tray

Japanese Patent No. 4179011 JP 2010-143777 A

Claims (9)

A folding means for folding the sheet or sheet bundle;
A paper discharge means for discharging the sheet or sheet bundle folded in half by the middle folding means;
Stacking means for stacking the sheets or sheet bundles discharged by the paper discharge means;
A sheet processing apparatus comprising:
A detection means provided on the upstream side of the paper discharge means for detecting the sheet or sheet bundle to be discharged;
A conveying unit that is provided in the stacking unit and conveys a sheet or a sheet bundle received from the sheet discharging unit side to the downstream side;
With
A sheet processing apparatus that determines an operation start timing and an operation stop timing of the transport unit based on a detection result of the detection unit. The sheet processing apparatus according to claim 1,
The operation start timing of the conveying unit is before the leading end of the sheet or sheet bundle reaches the conveying unit and after the conveying unit has reached a steady rotational speed. The sheet processing apparatus according to claim 1,
The operation stop timing of the conveying means is such that the trailing edge of the sheet or sheet bundle passes through the paper discharge means, the succeeding sheet or sheet bundle is conveyed, and a preset overlap amount with the preceding sheet or sheet bundle A sheet processing apparatus, which is after securing The sheet processing apparatus according to any one of claims 1 to 3,
The sheet processing apparatus according to claim 1, wherein a conveying speed of the conveying unit is lower than a conveying speed of the paper discharging unit. The sheet processing apparatus according to any one of claims 1 to 4,
The sheet stacking surface of the stacking means includes an inclined surface, a curved surface, and a substantially horizontal plane that form one surface continuously along the sheet discharging direction.
The sheet stacking surface is provided with an endless transport belt for transporting sheets along the sheet stacking surface,
Conveying rollers for providing a conveying force to the sheet or sheet bundle conveyed to the sheet stacking surface are provided on the inclined surface,
The sheet processing apparatus, wherein the conveying unit is configured by the conveying belt and the conveying roller. The sheet processing apparatus according to claim 5,
The sheet processing apparatus, wherein the conveyance belt and the conveyance roller are driven by the same drive source. The sheet processing apparatus according to any one of claims 1 to 6,
A sheet processing apparatus further comprising a sheet stacking auxiliary unit that takes two positions, a sheet stacking position and a retracted position retracted from the sheet stacking position, downstream of the stacking unit.   An image forming system comprising the sheet processing apparatus according to claim 1. A folding means for folding the sheet or sheet bundle;
A paper discharge means for discharging the sheet or sheet bundle folded in half by the middle folding means;
Stacking means for stacking the discharged sheet or sheet bundle;
A sheet stacking method in a sheet processing apparatus having:
A first step of detecting the sheet or sheet bundle discharged from the paper discharge means by a detection means provided between the paper discharge means and the stacking means;
A second step of receiving a sheet or a sheet bundle ejected from the paper ejection means by the conveyance means provided in the stacking means, and conveying the sheet or sheet bundle downstream;
A third step of determining an operation start timing and an operation stop timing of the transport means in the second step based on the detection result detected in the first step;
In the third step, the operation is started before the leading edge of the sheet or sheet bundle reaches the conveying means and after the conveying means reaches a steady rotational speed, and the trailing edge of the sheet or sheet bundle is After exiting the paper discharge means, the succeeding sheet or sheet bundle is conveyed, and after securing a preset overlap amount with the preceding sheet or sheet bundle, the operation is stopped, and the sheet or sheet bundle is placed on the stacking means. A sheet stacking method comprising stacking and stacking the overlap amount.