JP2008184326A - Sheet folding device, post-processing device with the same, and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet folding device capable of accurately positioning stacked bundles of sheets in a following stitching position or a folding position without a jam of sheets and incorrect collating when stacking sheets. <P>SOLUTION: When stacking sheets from an image forming device in a folding route, a sheet carry-in position, a stapling position and a sheet folding position are arranged in this order. The folding route is provided with a switch-back approach path so that a rear end of the stacked sheets and a tip of a carried-in sheet are overlapped with each other in the sheet carry-in position. A sheet tip regulating means is arranged in the route to freely adjust position thereof, and the regulating means controls the sheets so as to be positioned in the overlap position, the stitching position and the folding position in this order. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet folding apparatus and a post-processing apparatus that folds a sheet conveyed from an image forming apparatus such as a copying machine or a printer at a predetermined crease position. The present invention relates to an improvement of a sheet folding mechanism that folds the sheet.

  2. Description of the Related Art Generally, a sheet folding apparatus that aligns sheets conveyed from an image forming apparatus and staples the sheet bundle and folds the sheet bundle into a booklet shape or folds without stapling is widely known. Such a folding apparatus is incorporated as a folding mechanism in a post-processing apparatus connected to a paper discharge port of the image forming apparatus, for example, and is used as a processing apparatus for stapling bookbinding and booklet folding and bookbinding.

  For example, Patent Document 1 discloses an apparatus that stacks sheets from an image forming apparatus in a conveyance path, staples the central portion of the sheet bundle, and then folds the center into a crease and stores it in a stacker. . This publication discloses an apparatus configured to move up and down in the path a stopper member that regulates the leading edge of the sheet in order to move the sheets accumulated in the path to the binding position and the folding position.

Further, in Patent Document 2, a flapper member is provided at a sheet carry-in entrance in order to prevent a subsequent sheet from entering between the preceding sheets and causing a disorder when stacking and stacking sheets in a path. An apparatus configuration for guiding sheets onto the stacked sheets is disclosed.
JP 2006008383 A JP-A-2005-041660

  When the sheets are stacked and stored in the path in which the sheet folding mechanism is arranged in the sheet folding apparatus as described above, when the preceding sheet is loaded into the path and the subsequent sheet is loaded from the rear end side as in Patent Document 1 described above. It is known that this sheet enters between the preceding and stacked sheets and causes disorder. In particular, when the front end of the sheet is regulated in order to position the stacked sheets at a predetermined folding position or staple binding position, in the case of a sheet having a different length size, for example, a short sheet, there is a gap between the rear end of the sheet and the rear end of the succeeding sheet. Arise. For this reason, it is not possible to guide the leading edge of the succeeding sheet onto the accumulated sheet, and the page order is likely to be out of order.

  For this reason, conventionally, a mechanism is used in which sheets are stacked in a bundle on the upstream side different from the sheet folding position or binding position and then conveyed to the binding position or folding position. On the other hand, as proposed in Patent Document 2 above, a flapper member for observing the sheet order and a driving means for operating the flapper member are provided at the sheet carry-in entrance, and at the same time, the front end of the sheet is set according to the length size. It has also been proposed to provide a sheet leading edge regulating member and a driving means for operating the regulating member such that the position is adjusted and the trailing edge of the sheet is guided by the flapper member.

  However, as in the above-mentioned Patent Document 2, if a guide mechanism such as a flapper and a sheet position restricting mechanism for adjusting the rear end position of the stacked sheets are arranged at the sheet carry-in entrance, the apparatus becomes complicated and operates according to a wide range of sheets. The control mechanism to control also becomes complicated.

  Accordingly, the inventor sets the sheet carry-in position, the staple binding position, and the sheet folding position to pre-calculated positions, so that the order of sheets stacked in the path is not out of order or jammed. The inventors have come up with the idea that positioning to the stapling position and folding position can be performed accurately with a single position regulating mechanism.

  Therefore, according to the present invention, when sheets are stacked at the sheet folding position, the sheet jam or page order does not get out of order, and the stacked sheet bundle can be accurately positioned at the subsequent binding processing or folding processing position. The main problem is to provide a sheet folding apparatus with a simple structure at low cost.

  In order to achieve the above object, according to the present invention, when sheets are stacked from an image forming apparatus or the like on a folding processing path, a sheet carry-in position, a staple binding position, and a sheet folding position are arranged in this order. A switchback approach path is provided in this path so that the rear end of the stacked sheets and the front end of the loaded sheet overlap at the sheet loading position. Accordingly, the sheet leading edge restricting means is disposed in the path so that the position can be adjusted, and the restricting means controls the sheet to be positioned in the order of the overlap position, the binding position, and the folding position.

The present invention adopts the following configuration in order to solve the above-described problems.
A sheet processing path for feeding a sheet from the carry-in port to a predetermined folding position; a stacking guide means for aligning sheets fed in sequence at the folding position and sequentially supplied; and the sheet processing path disposed in the sheet processing path. A sheet leading edge restricting means for restricting the position of the sheets stacked on the collecting guide means; a shift means for moving the sheet leading edge restricting means along the sheet processing path; and a folding means disposed at the folding position. Folding roll means for folding the accumulated sheet bundle, and stapling means for binding the sheet bundle arranged on the upstream side of the folding roll means and accumulated on the accumulation guide means.

  The sheet processing path includes a sheet entry path for carrying sheets toward the accumulation guide means and a switchback entry path for moving the rear end of the sheet supported by the accumulation guide means backward to a predetermined amount upstream. The switchback approach path is configured such that the sheet supported by the stacking guide means can be moved to an overlap position where the trailing edge overlaps the leading edge of the sheet from the sheet carry-in path. The shift means (1) moves a sheet rear end supported by the stacking guide means to the overlap position when a sheet enters the stacking guide means from the sheet entrance path, and (2) the staple. When binding by means, the sheet supported by the stacking guide means is moved to the sheet binding position. (3) When folding by the folding roll means, the sheet supported by the stacking guide means is folded. The position of the sheet leading edge restricting means is controlled so as to move to the position.

  The sheet leading edge restricting means is disposed in the sheet processing path so as to be movable at least at first, second, and third positions at a distance from the upstream side to the downstream side. The shift means positions the sheet leading edge restricting means, (1) positions the sheet supported by the accumulation guide means at the first position at the overlap position, and (2) positions the accumulation guide at the second position. The sheet supported by the means is positioned at the sheet binding position, and (3) the sheet supported by the stacking guide means is positioned at the folding position at the third position.

  The sheet processing path includes a switchback conveyance path that reverses the conveyance direction after conveying a sheet from the carry-in entrance in a predetermined direction.

  The sheet processing path is provided with sheet side edge aligning means for aligning sheets supported by the stacking guide means. The sheet side edge aligning means includes a pair of aligning plates engaged with the sheet side edges, and the aligning plate. The operating means for moving the approaching / separating means from each other, and the operating means is configured to adjust the pair of alignment plates in a state in which the sheet leading edge restricting means restricts the sheet supported by the stacking guide means to a sheet binding position or a folding position. Alignment works.

  The sheet processing path is formed in a curved or bent shape in which a sheet supported by the stacking guide means protrudes toward the switchback approach path and the stapling means and / or folding roll means.

  The sheet leading edge restricting means includes a locking member that locks the sheet leading edge and a grip member that grips the sheet, and the sheet grip member releases the grip in conjunction with or in synchronization with the operation of the shift means.

  A post-processing apparatus according to the present invention includes a sheet carry-in path having a carry-in entrance for sequentially carrying sheets, a first switchback conveyance path that branches from the carry-in path and reverses the sheet conveyance direction, and the first A second switchback conveyance path disposed upstream of the switchback conveyance path and branching off from the sheet carry-in path and reversing the sheet conveyance direction; and a sheet folding apparatus disposed in the second switchback conveyance path The sheet folding device has any one of the above-described configurations.

  An image forming system according to the present invention includes an image forming apparatus that sequentially forms an image on a sheet, and a post-processing apparatus that performs post-processing such as stapling, stamping, and punching on the sheet from the image forming apparatus. To do.

  In the present invention, when a sheet is carried into the stacking guide means arranged at the sheet folding position, the rear end of the sheet supported by the guide means is retracted to the switchback entry path so as to overlap the leading end of the carried-in sheet. After the stacking, the position control is performed by moving the position of the sheet leading edge regulating means to the binding position and then the folding position of the sheet bundle, and the following effects are obtained.

  Position control of leading edge restricting means such as a stopper member that restricts the leading edge of the sheet, the sheet loading order is aligned, the binding position is positioned, and the folding position is accurately controlled by simple control. It can be made. Therefore, there is no possibility of jamming and page misalignment when a sheet is carried in, and at the same time, the positioning to the binding position and the folding position can be simply configured with a simple structure.

  Further, according to the present invention, the stacking guide means is configured to be bent (or bent), and the stapling means and the folding roll means are arranged on the protruding side of the bending guide. The curl is corrected, and the sheet curl is not affected at the time of carrying in the sheet, stapling, and roll folding, and the respective operations are performed accurately.

  Further, by providing a grip member for gripping sheets in a bundle shape on the sheet leading edge regulating means, the sheet bundle can be positioned at the processing position with an accurate posture.

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 shows an overall configuration of an image forming system according to the present invention, FIG. 2 is an explanatory diagram of the overall configuration of a post-processing apparatus, and FIG. 3 is an explanatory diagram showing a detailed configuration of a sheet folding unit. Therefore, the image forming system shown in FIG. 1 includes an image forming apparatus A and a post-processing apparatus B. The post-processing apparatus B incorporates a sheet folding apparatus C as a unit. This will be sequentially described below.

[Configuration of Image Forming Apparatus]
The image forming apparatus A shown in FIG. 1 sends a sheet from the sheet feeding unit 1 to the image forming unit 2, prints the sheet on the image forming unit 2, and then carries the sheet out from the main body discharge port 3. The sheet feeding unit 1 stores sheets of a plurality of sizes in sheet feeding cassettes 1 a and 1 b, and separates designated sheets one by one and feeds them to the image forming unit 2. The image forming unit 2 includes, for example, an electrostatic drum 4, a print head (laser light emitting device) 5 and a developing device 6 arranged around the electrostatic drum 4, a transfer charger 7, and a fixing device 8. An electrostatic latent image is formed by the light emitting device 5, toner is adhered to the developing device 6, an image is transferred onto the sheet by the transfer charger 7, and heat fixing is performed by the fixing device 8. The sheets on which images are formed in this way are sequentially carried out from the main body discharge port 3. 9 is a circulation path, and the sheet printed on the front side from the fixing device 8 is turned upside down through the main body switchback path 10 and then fed again to the image forming unit 2 to print on the back side of the sheet. This is the path for duplex printing. The sheet printed on both sides in this way is turned upside down by the main body switchback path 10 and then carried out from the main body discharge port 3.

  11 is an image reading apparatus, which scans a document sheet set on a platen 12 with a scanning unit 13 and electrically reads it with a photoelectric conversion element (not shown). The image data is digitally processed by an image processing unit, for example, and then transferred to the data storage unit 14 to send an image signal to the laser emitter 5. 15 is a document feeding device 15, which is a feeder device that feeds document sheets stored in the stacker 16 to the platen 12.

  The image forming apparatus A configured as described above is provided with a control unit (controller) shown in FIG. 9, and image forming conditions such as sheet size designation, color / monochrome printing designation, print number designation, single-sided / double-sided printing designation from the control panel 18. The printout conditions such as enlargement / reduction print designation are set. On the other hand, in the image forming apparatus A, image data read by the scan unit 13 or image data transferred from an external network is accumulated in the data storage unit 17, and the image data is transferred from the data storage unit 17 to the buffer memory 19. The data signal is sequentially transferred from the buffer memory 19 to the laser emitter 5.

  From the control panel 18, post-processing conditions are also input and specified simultaneously with the image forming conditions. As the post-processing conditions, for example, “print-out mode”, “staple binding mode”, “sheet bundle folding mode”, or the like is designated. The image forming apparatus A forms an image on the sheet according to the image forming condition and the post-processing condition. This image forming mode will be described with reference to FIG. 5. When “single-sided printing” is set as the image forming condition and “print out mode” or “staple binding mode” is set as the post-processing condition, the image forming unit 2 designates A predetermined image is formed on the sheet, and the sheet is turned upside down by the main body switchback path 10 and then carried out to the main body discharge port 3.

  Accordingly, the image forming apparatus A sequentially forms a series of sheets from the first page to the nth page. A post-processing apparatus B, which will be described later, receives sheets carried out face down from the first page. When in the “print-out mode”, the sheets are sequentially stacked and stored in the first paper discharge tray 21 arranged in the post-processing apparatus B. In the “staple binding mode”, the sheets are stacked and stored in the first stacking unit (stacking tray) 29 disposed in the post-processing apparatus B. Then, the sheets stacked on the tray are bound together by an end face binding and stapling device 33 which will be described later in response to a job end signal, and stored in the first paper discharge tray 21.

Also, when double-sided printing and 2-in-1 printing are specified in the image forming conditions and “sheet bundle folding mode” is set as post-processing, when the last page is n pages as shown in FIG. (N / 2) page image and (n / 2 + 1) page image on the front side of the sheet, and (n / 2-1) page image and (n / 2 + 2) page on the back side. Are formed and carried out from the main body discharge port 3. Then, the post-processing apparatus B described later stores the sheet in the second stacking unit (stacking guide) 35 from the sheet carry-in path P1.
Next, the image forming apparatus A prints the (n / 2-2) page image and the (n / 2 + 3) page image on the front side of the next sheet, and the (n / 2-3) page on the back side. And the (n / 2 + 4) th page image are printed out from the main body discharge port 3. Then, the post-processing apparatus B stacks and accumulates the sheets on the previous sheet. In this manner, the image forming apparatus A forms an image in an order suitable for the stacking tray structure of the post-processing apparatus B. Such a page order controls the print head (laser emitter) 5 by calculating the print order when transferring image data from the data storage unit 17 to the buffer memory 19.

[Configuration of post-processing equipment]
The post-processing apparatus B connected to the image forming apparatus A described above receives a sheet on which an image is formed from the main body discharge port 3 of the image forming apparatus A, and (1) whether the sheet is accommodated in the discharge tray 21 ( (2) Whether the sheets from the main body discharge port 3 are aligned in a bundle and stapled, and then stored in the discharge tray 21 (described above “staple binding mode”) ( 3) After the sheets from the main body discharge port 3 are aligned in a bundle, they are folded into a booklet and stored in the second discharge tray 22 (the above-described “sheet bundle folding mode”).

  Therefore, as shown in FIG. 2, the post-processing apparatus B includes the first paper discharge tray 21 and the second paper discharge tray 22 in the casing 20, and a sheet carry-in path P <b> 1 having a carry-in port 23 connected to the main body discharge port 3. Is provided. The sheet carry-in path P <b> 1 is configured by a substantially horizontal straight path in the casing 20. A first switchback conveyance path SP1 and a second switchback conveyance path SP2 that branch from the sheet carry-in path P1 and transfer the sheet in the reverse direction are arranged. The first switchback transport path SP1 is branched from the sheet carry-in path P1 on the downstream side and the second switchback transport path SP2 is branched on the upstream side of the path, and the both transport paths are arranged at a distance from each other.

  The second switchback conveyance path SP2 is provided with a stacking guide 35 to be described later, and a sheet processing path P2 for feeding the sheet to a predetermined folding position Y is formed in the second switchback conveyance path SP2.

  In such a path configuration, the carry-in roller 24 and the paper discharge roller 25 are arranged in the sheet carry-in path P1, and these rollers are connected to a drive motor M1 (not shown) that can be rotated forward and backward. Further, a path switching piece 27 for guiding the sheet to the second switchback conveying path SP2 is disposed in the sheet carry-in path P1, and is connected to an operating means such as a solenoid. Further, a buffer guide 26 is provided in the sheet carry-in path P1 for temporarily staying and holding the sheet reaching the second switchback transport path SP2. A post-processing unit 28 is provided between the carry-in port 23 and the carry-in roller 24 to perform post-processing such as stamping (stamping means) and punching (punching means) on the sheet from the image forming apparatus A.

[Configuration of the first switchback transport path SP1]
As described above, the first switchback conveyance path SP1 disposed on the downstream side (rear end portion of the apparatus) of the sheet carry-in path P1 is configured as follows. A discharge roller 25 and a discharge port 25a are provided at the exit end of the sheet carry-in path P1, and a first stacking unit 29 is provided below the discharge port 25a with a step difference. The first stacking unit 29 includes a tray (hereinafter referred to as “stacking tray 29”) for stacking and supporting sheets from the sheet discharge outlet 25a. Above the stacking tray 29, a forward / reverse roller 30 is disposed so as to be movable up and down between a position in contact with the sheet on the tray and a separated standby position (a chain line position in FIG. 3). A forward / reverse motor M2 is connected to the forward / reverse roller 30 and rotates in the clockwise direction when the sheet enters the stacking tray 29, and rotates in the counterclockwise direction after the trailing edge of the sheet enters the tray. To be controlled. Accordingly, a first switchback transport path SP1 is formed on the stacking tray 29. 31 is a caterpillar belt, and the discharge roller 25 and one end pulley side are pressed against each other, and the end pulley side is pivotally supported so as to be suspended from the collecting tray 29 around the pulley shaft 31a. A driven roller 30 b shown in the figure is engaged with the forward / reverse roller 30 and is provided on the stacking tray 29.

  With the above configuration, the sheet from the discharge port 25a enters the stacking tray 29 and is transferred toward the first discharge tray 21 by the forward / reverse rotation roller 30, and the rear end of the sheet is transferred from the discharge port 25a to the stacking tray 29. After entering, when the forward / reverse roller 30 is rotated in the reverse direction (counterclockwise in the figure), the sheet on the tray is transferred in the direction opposite to the paper discharge direction. At this time, the caterpillar belt 31 switches back and conveys the sheet trailing edge along the stacking tray 29 in cooperation with the forward / reverse roller 30.

  A trailing edge regulating member 32 and a stapling device 33 for regulating the position of the trailing edge of the sheet are disposed at the trailing edge of the stacking tray 29 in the paper discharge direction. The illustrated stapling device 33 is constituted by an end-face binding stapler, and staples the staple at one place or a plurality of places on the rear end edge of the sheet bundle stacked on the tray. Further, the trailing edge regulating member 32 reciprocates in the paper discharge direction along the stacking tray 29 in order to share the function of carrying out the staple-bound sheet bundle to the first paper discharge tray 21 disposed on the downstream side of the stacking tray 29. It is configured to move freely. The carry-out mechanism of the illustrated rear end regulating member 32 includes a grip claw 33a that grips the sheet bundle and a rear end regulating surface 33b that abuts and regulates the rear end of the sheet, and extends in the horizontal direction in the figure along a guide rail provided on the apparatus frame. It is configured to be movable. 34b shown in the figure is a drive arm that reciprocates the rear end regulating member 32, and is connected to the paper discharge motor M3.

  Further, the stacking tray 29 is provided with a side aligning plate 34a for aligning the width direction of the sheets stacked on the tray. The side aligning plate 34a is arranged on the left and right sides (around FIG. 3) so as to align the sheets with the center reference. It is composed of a pair of alignment plates, is configured to approach and separate from the center of the sheet, and is connected to an alignment motor M4 (not shown).

  The first switchback conveying path SP1 configured as described above aligns the sheets from the sheet discharge outlet 25a on the stacking tray 29 in the “staple binding mode”, and this sheet bundle is rear-bound by the end surface binding stapler 33. One or more edges are stapled. In the “print-out mode”, the sheet fed along the stacking tray 29 is conveyed between the forward / reverse roller 30 and the driven roller 30b without the switchback conveyance of the sheet from the sheet discharge port 25a. It is carried out to the paper tray 21. In this way, the illustrated apparatus is characterized in that the apparatus is compactly configured by supporting the sheets to be stapled by the stacking tray 29 and the first discharge tray 21 in a bridge manner.

[Configuration of second switchback transport path]
The configuration of the second switchback conveyance path SP2 branched from the sheet carry-in path P1 will be described. As shown in FIG. 4, the second switchback conveying path (sheet processing path) SP2 is disposed substantially vertically in the apparatus casing 20, and includes a sheet entrance path 35a, a stacking guide (stacking guide means; the same applies hereinafter) 35b, And a switchback approach path 35c. The sheet entry path 35a and the accumulation guide 35b are connected to form a step as illustrated, and the switchback entry path 35c is connected to the rear end side of the accumulation guide 35b. In the sheet entrance path 35a, a transport roller 36 is disposed at the path entrance, and a transport roller 37 is disposed at the path exit. A saddle stitching stapling device 40 and folding roll means 45 are disposed on the accumulation guide 35b. Hereinafter, these configurations will be sequentially described.

  First, the accumulation guide 35b is formed by a guide member for guiding the conveyance of the sheet, and is configured to stack and store the sheet on the guide. The illustrated accumulation guide 35 b is configured as a part of the second switchback conveyance path (sheet processing path) SP <b> 2 and is disposed substantially vertically in the center of the apparatus casing 20. As a result, the apparatus is made compact and compact. The accumulation guide 35b is formed in a length shape that accommodates the maximum size sheet therein, and in particular, the illustrated guide is bent or bent so as to protrude to the side where the saddle stitching staple device 40 and the folding roll means 45 described later are disposed. It is configured in shape.

  A switchback entry path 35c that overlaps the exit end of the sheet entry path 35a is connected to the rear end side in the transport direction of the stacking guide 35b. This stacks by overlapping the leading edge of the loaded (following) sheet sent from the conveying roller 37 of the second switchback conveying path SP2 and the trailing edge of the stacked (preceding) sheet supported by the stacking guide 35b. This is for securing the page order of sheets. The accumulation guide 35b is provided with a sheet leading edge regulating means 38 for regulating the sheet leading edge on the downstream side of the guide.

[Configuration of sheet tip regulating means]
As shown in FIG. 10, the sheet leading edge regulating means 38 holds a locking member 38a for locking the leading edge of the sheet carried along the stacking guide 35b, and a sheet bundle stacked and supported by the locking member 38a. The grip member 38b is used. The sheet front end regulating means 38 is supported by a guide rail 38g so as to be movable along the accumulation guide 35b. The grip member 38b is axially supported by the locking member 38a and nips the sheet supported by the locking member 38a. An energizing spring 38s and an actuating solenoid 38L are connected to the grip member 38b, and the energizing spring 38s always operates in the grip releasing direction of the seat so that the sheet is gripped and gripped when the actuating solenoid 38L is energized. It has become.

  The sheet leading edge regulating means 38 configured in this way is configured to move between the sh1, sh2, and sh3 shown in the figure by the shift means MS. The shift means MS is composed of a stepping motor 38M, a pinion 38p connected to the motor 38M, and a rack gear 38r integrally formed with the sheet leading edge regulating means 38, and the step stepping motor 38M is predetermined by a detection signal from the home position sensor PS. The sheet leading edge regulating means 38 is configured to move to Sh1, Sh2, and Sh3 in the figure by being rotationally driven. The grip member 38b grips the sheet bundle accumulated in the accumulation guide 35b by turning on and off the operation solenoid 38L. In this case, when the sheet leading edge regulating means 38 is moved from the upstream side to the downstream side (Sh3 → Sh1, etc.), the operation solenoid 38L is turned on to control the grip of the sheet bundle. The locking member 38a for supporting the leading edge of the sheet and the grip member 38b for gripping the sheet bundle supported by the sheet are integrally formed as shown in the figure, but they are separated and individually attached to the apparatus frame. Also good.

  The shift means MS moves the sheet leading edge regulating means 38 at least between the illustrated positions Sh1, Sh2, and Sh3. (1) When a sheet enters the stacking guide 35b from the sheet entrance path 35a, the sheet leading edge regulating means 38 is moved to the illustrated position Sh3 so that the rear end of the sheet supported by the stacking guide 35b is returned to the switchback entrance path 35c. (2) When the sheets are stapled by the saddle stitching stapling device 40, the sheet leading edge regulating means 38 is moved to the illustrated position Sh2 so as to position the sheet supported by the accumulation guide 35b at the binding position X. 3) When folding by the folding roll means 45, the sheet leading edge regulating means 38 is moved to the illustrated position Sh1 so that the sheet supported by the stacking guide 35b is positioned at the folding position Y.

  That is, when the sheet leading edge regulating means 38 is positioned at the illustrated position Sh3, the rear end of the sheet (bundle) supported by the stacking guide 35b enters the switchback entry path 35c as shown in FIG. Subsequent sheets sent from the sheet entry path 35a are surely stacked above the accumulated sheets. When the sheet leading edge regulating means 38 is positioned at the illustrated position Sh2, the center of the sheet (bundle) supported by the stacking guide 35b is positioned at the binding position X of the saddle stitching staple device 40 as shown in FIG. Similarly, when the sheet leading edge regulating means 38 is positioned at the illustrated position Sh1, the center of the sheet bundle stapled and supported by the stacking guide 35b as shown in FIG. 12D is set at a folding position Y of the folding roll means 45 described later. It is designed to be positioned. Accordingly, the illustrated positions Sh1, Sh2, and Sh3 are set to optimal positions according to the sheet size (length in the conveyance direction), and are prepared in advance on a memory table or the like.

  In the stacking guide 35b, a sheet side edge aligning unit 39 is disposed on the downstream side in the sheet conveying direction. The sheet side edge aligning means 39 aligns so that the position in the width direction of the sheet carried into the stacking guide 35b and supported by the sheet leading edge restricting means 38 is matched. In other words, the sheet side edge regulating means 38 is positioned at the position Sh3, and the sheet side edges are aligned by a pair of alignment plates (sheet side edge alignment means) 39 with the entire sheet supported by the accumulation guide 35b. In the illustrated apparatus, the sheet side edge aligning means 39 is composed of a pair of left and right aligning plates so that the sheets are aligned with respect to each other based on the center reference. The sheet bundle supported on the sheet is aligned and aligned. For this reason, the sheet side edge aligning means 39 is connected to an alignment motor M5 (not shown).

  That is, the sheet side edge aligning means 39 is composed of a pair of aligning plates that engage with the sheet side edges, and an operating means (the above-described aligning motor M5) that moves the aligning plates toward and away from each other. The aligning motor M5 is configured so that the pair of aligning plates align and align the sheets in a state in which the sheet front end restricting means 38 restricts the sheet supported by the accumulation guide 35b to the sheet binding position X or the folding position Y. The alignment plate approaches and separates.

[Configuration of Saddle Stitcher]
A binding position X is set on the upstream side and a folding position Y is set on the downstream side along the stacking guide 35b, and the saddle stitching staple device 40 is disposed in the binding position X. This apparatus is composed of a driver unit 40A and an anvil unit 40B, and each unit is configured to be separated at opposing positions with the integrated guide 35b interposed therebetween. A needle cartridge is mounted on the driver unit 40A, and a needle connected in a belt shape is built in the cartridge. The needle member at the tip is bent into a U shape by the former member by a driver member that moves up and down between the upper dead center and the lower bottom dead center, and then this needle is inserted into the sheet bundle. Has been. Accordingly, the driver unit 40A includes a drive motor M, a drive arm that moves the driver member up and down, a drive cam that drives the arm, and the like.

  On the other hand, the anvil unit 40B is provided with a bending groove (not shown) for bending the tip of the staple needle inserted into the sheet bundle. The saddle stitching and stapling apparatus 40 configured as described above is configured such that the driver unit 40A and the anvil unit 40B are separated from each other so that a sheet bundle can pass between them. Accordingly, it is possible to staple the central portion of the sheet bundle and other arbitrary positions.

[Configuration of folding roll means]
A folding roll means 45 that folds the sheet bundle and a folding blade 46 that inserts the sheet bundle at the nip position NP of the folding roll means 45 are provided at the folding position Y arranged on the downstream side of the saddle stitching stapler 40 described above. It has been. As shown in FIGS. 6 (a) and 6 (b), the folding roll means 45 is composed of folding rolls 45a and 45b that are in pressure contact with each other, and each roll is formed substantially in the width of the maximum sheet. The pair of folding rolls 45a and 45b are fitted with rotation shafts 45ax and 45bx in the long grooves of the apparatus frame so as to be in pressure contact with each other, and are urged in the pressure contact direction by compression springs 45aS and 45bS. The folding rolls 45a and 45b may be structured such that at least one of them is axially supported so as to be movable in the press-contact direction, and a biasing spring is stretched over one of the folding rolls 45a and 45b.

  The pair of folding rolls 45a and 45b is formed of a material having a relatively large friction coefficient such as a rubber roller. This is because the sheet is bent and transferred by a soft material such as rubber, and may be formed by lining the rubber material. The folding roll means 45 is formed in an uneven shape as shown in FIG. 6B, and a gap 45g is formed in the sheet value width direction. The gap 45g is arranged so as to coincide with the unevenness of the folding blade 46, which will be described later, and consideration is given so that the tip of the folding blade can easily enter between the roll nips. At the same time, the gap 45g is arranged at a width position that coincides with a staple binding portion for binding the sheet bundle. In other words, the pair of folding rolls 45a and 45b that are in pressure contact with each other are formed in a concavo-convex shape having a gap (gap 45g) in the sheet width direction. The blade edge is designed to enter.

  Each of the folding rolls 45a and 45b is connected to roll driving means. The illustrated roll drive means RM is composed of a roll drive motor M6 and a transmission mechanism (transmission means) 47V as shown in FIGS. The illustrated transmission means 47V is composed of a transmission belt that decelerates the rotation of the roll drive motor M6 and transmits it to the transmission shaft 47X. Clutch means 45c is disposed between the transmission shaft 47X and the rotation shaft 45ax of the first folding roll 45a. Similarly, a clutch means 45c is also arranged between the second folding roll 45b and the rotation shaft 45bx. This clutch means 45c is an electromagnetic clutch, a one-way clutch (one-way clutch), a sliding friction clutch (spring clutch), etc., and the drive rotation of the roll drive motor M6 is turned on and off to the first folding roll 45a and the second folding roll 45b. Configure as you can.

  The illustrated clutch means 45c is constituted by a one-way clutch, and is configured to transmit the rotation of the transmission shaft 47X to the transmission collar 47Z only in one direction between the transmission shaft 47X and the transmission collar 47Z. The first folding roll 45a is gear-connected to the transmission collar 47Z, and the second folding roll 45b is belt-connected. Thus, only one direction of rotation of the motor is transmitted to the first and second folding rolls 45a and 45b connected to the roll drive motor M6 via the clutch means 45c, and the folding rolls 45a and 45b are simultaneously fed out of the sheet. It is configured to be freely rotatable in the direction.

  The pair of folding rolls 45a and 45b described above are positioned on the curved or bent protruding side of the stacking guide 35b, and are separated from the sheet bundle supported by the stacking guide 35b by a distance h shown in FIG. Is arranged. That is, the sheet (bundle) supported by the accumulation guide 35b is arranged at a position where the roll surface does not come in contact with the distance h. And the folding blade 46 which has a knife edge is provided in the position which opposes on both sides of a sheet | seat bundle. The folding blade 46 is supported by the apparatus frame so as to be able to reciprocate between the standby position in FIG. 8A and the nip position in FIG. Blade driving means BM is connected to the folding blade 46. The folding blade 46 is configured to reciprocate by the drive motor M7 between the standby position retracted from the sheet bundle supported by the stacking guide 35b and the nip position between the pressure contacts of the folding roll means 45. The folding blade 46 is formed in a plate shape with a material having a relatively small coefficient of friction such as metal, and the tip thereof is formed in an uneven surface as shown in FIG. As described above, the blade tip is formed in a shape that enters the cap 45g of the folding rolls 45a and 45b.

  Therefore, in the figure, the relationship between the friction coefficient ν1 between the folding rolls 45a and 45b and the sheet, the friction coefficient ν2 between the sheets, and the friction coefficient ν3 between the sheet and the folding blade 46 is “ν1> ν2> ν3. "Is set. Therefore, in the state where the sheet bundle shown in FIG. 8C is inserted between the first folding roll 45a and the second folding roll 45b by the folding blade 46, the pressure contact force acting on the both folding rolls 45a and 45b is It reaches each as a force equal to the sheet bundle and blade. At this time, since the friction coefficient is set to the above relationship, the sheet bundle is smoothly fed in the feeding direction (left side in the figure).

  Next, the configuration of the blade driving means BM of the folding blade 46 will be described. As shown in FIG. 7B, the folding blade 46 is supported on the apparatus frame by a guide rail 46g so as to be movable in the sheet folding direction. The folding blade 46 is supported so as to reciprocate between a standby position retracted from the sheet supported by the stacking guide 35b and a nip position of the folding rolls 45a and 45b. The blade drive means BM for reciprocating the folding blade 46 is constituted by a blade drive motor M7 and a transmission means 46V for transmitting the rotation thereof, and the illustrated one is transmitted to the transmission rotation shaft 46X by a transmission belt. The transmission rotation shaft 46X is provided with a transmission pinion 46P and meshed with a rack gear 46L attached integrally to the folding blade 46.

  Therefore, when the blade drive motor M7 rotates forward and backward, the folding blade 46 reciprocates between the standby position and the nip position along the guide rail 46g. The folding blade 46 is constituted by a plate-like member having a knife edge in the sheet width direction, and the tip thereof is formed in an uneven shape as shown in the figure.

  Next, the sheet folding state by the folding roll means 45 and the folding blade 46 having the above-described configuration will be described with reference to FIGS. First, the sheet bundle supported by the stacking guide 35b in the form of a bundle is locked by the sheet leading edge restricting means 38 in the state shown in FIG. 5A, and the fold position is positioned at the folding position Y in the stapled state. . Upon obtaining this sheet bundle setting end signal, the drive control means (sheet folding operation control section, which will be described later) 64d turns off the clutch means 45c. In the illustrated one-way clutch configuration, the roll drive motor M6 is stopped, or the motor M6 is rotated at a lower speed than the moving speed of the folding blade 46. This is to create a condition for the first and second folding rolls 45a and 45b to be driven and rotated by the sheet bundle inserted into the nip position by the folding blade 46, as will be described later.

  Therefore, the drive control means 64d moves the folding blade 46 from the standby position toward the nip position at a predetermined speed. The rotational speed VR of the folding rolls 45a and 45b is set to zero or VB> VR with respect to the moving speed VB. Therefore, in the state of FIG. 8B, the sheet bundle is bent at the fold position by the folding blade 46 and inserted between the rolls. At this time, the first folding roll 45 a and the second folding roll 45 b are driven and rotated continuously with the sheet moving by the folding blade 46. The drive control means 64d stops the blade drive motor M7 after the expected time for the sheet bundle to reach the predetermined nip position, and stops the folding blade 46 at the position shown in FIG. Around this time, the drive control means 64d switches the clutch means 45c to the ON state to drive and rotate the folding rolls 45a and 45b. Then, the sheet bundle is sent out in the feeding direction (left side in the figure). Thereafter, the drive control means 64d moves and returns the folding blade 46 located at the nip position to the standby position in parallel with the feeding of the sheet bundle by the folding rolls 45a and 45b in the state shown in FIG.

  When the sheet bundle thus folded is first engulfed between the pair of folding rolls 45a and 45b, the sheet contacting the roll surface is not drawn between the rolls by the rotating roll. That is, since the folding rolls 45a and 45b follow (follow) the sheet to be inserted (pressed) and rotate, only the sheet in contact with the roll will not be wound first. Further, since the folding rolls 45a and 45b follow and rotate following the inserted sheet, the roll surface and the sheet in contact therewith are not rubbed, and image rubbing is not caused.

[Description of control configuration]
The control configuration of the above-described image forming system will be described with reference to the block diagram of FIG. The image forming system shown in FIG. 1 includes a control unit (hereinafter referred to as “main body control unit”) 50 of the image forming apparatus A and a control unit (hereinafter referred to as “post-processing control unit”) 60 of the post-processing apparatus B. The main body control unit 50 includes an image formation control unit 51, a paper feed control unit 52, and an input unit 53. Then, the “image forming mode” and “post-processing mode” are set from the control panel 18 provided in the input unit 53. As described above, the image forming mode sets the number of printouts, sheet size, color / monochrome printing, enlargement / reduction printing, duplex / single-sided printing, and other image formation conditions. Then, the main body control unit 50 controls the image formation control unit and the paper feed control unit according to the set image forming conditions, and after the image is formed on a predetermined sheet, the sheets are sequentially carried out from the main body discharge port 3.

  At the same time, the post-processing mode is set by input from the control panel 18. The post-processing mode is set to, for example, “print-out mode”, “staple binding finishing mode”, “sheet bundle folding finishing mode”, or the like. Therefore, the main body control unit 50 transfers the post-processing finishing mode, the number of sheets, the upper number of copies, and the binding mode (one-position binding or two or more bindings) information to the post-processing control unit 60. At the same time, the main body control unit 50 transfers a job end signal to the post-processing control unit 60 every time image formation is completed.

  The post-processing control unit 60 includes a control CPU 61 that operates the post-processing apparatus B in accordance with a designated finishing mode, a ROM 62 that stores an operation program, and a RAM 63 that stores control data. In the RAM 63, position data of the sheet locking positions Sh1, Sh2, Sh3 of the sheet leading edge regulating means 38 is prepared in a data table, for example, in accordance with the size (length in the conveying direction) of the sheet transferred to the sheet processing path P2. ing. The control CPU 61 includes a sheet conveyance control unit 64 a that performs conveyance of the sheet sent to the carry-in entrance 23, a sheet accumulation operation control unit 64 b that performs sheet accumulation operation, and a sheet binding process that performs sheet binding processing. An operation control unit 64c and a sheet folding operation control unit 64d for performing a sheet folding operation are provided.

  The sheet conveyance control unit 64a is connected to the control circuit of the driving motor M1 of the conveyance roller 24 and the discharge roller 25 of the sheet conveyance path P1 and receives a detection signal from the sheet sensor S1 disposed in this path. It is configured as follows. Further, the sheet stacking operation control unit 64b drives the forward / reverse rotation motor M2 of the forward / reverse rotation roller 30 and the discharge motor M3 of the trailing end regulating member 32 in order to stack sheets on the first stacking unit (stacking tray) 29. Connected to the circuit. Further, the sheet binding processing operation control unit 64c is connected to a drive circuit of a drive motor M incorporated in the saddle stitching staple device 40 of the end stacking staple device 33 and the second stacking unit (stacking guide) 35 of the first stacking unit 29. Has been.

  The sheet folding operation control unit 64d is connected to a drive circuit of a roll drive motor M6 that drives and rotates the folding rolls 45a and 45b and a control circuit of the clutch means 45c. The sheet folding operation control unit 64d is connected to a control circuit of a shift unit MS that controls the movement of the transport rollers 36 and 37 of the sheet entrance path 35a and the sheet leading end regulating unit 38 of the stacking guide 35b to predetermined positions. It is wired so as to receive a detection signal from a sheet sensor arranged in the route.

The control unit configured as described above causes the post-processing apparatus B to execute the next processing operation.
"Printout mode"
In this mode, the image forming apparatus A forms an image of a series of documents, for example, from the first page, and sequentially carries out face-down from the main body discharge port 3. Therefore, the post-processing apparatus B retracts the buffer guide 26 in the sheet carry-in path P1 upward in FIG. 3, and moves the path switching piece 27 to the state of the solid line in FIG. As a result, the sheet sent to the sheet carry-in path P <b> 1 is guided to the paper discharge roller 25. Therefore, after the expected time that the leading edge of the sheet reaches the forward / reverse roller 30 of the stacking tray 29 based on the signal detected by the sheet discharge port 25a, the sheet conveyance control unit 64a moves the forward / reverse roller 30 from the upper standby position onto the tray. Then, the forward and reverse rollers are rotated clockwise in FIG. Then, the sheet that has entered the stacking tray 29 is carried out toward the first paper discharge tray 21 by the forward / reverse rotation roller 30 and stored on the tray. The successive sheets are sequentially carried out to the first paper discharge tray 21 and accumulated and stored on the tray.

  Accordingly, in this printout mode, the sheets on which the image is formed by the image forming apparatus A are accommodated in the first paper discharge tray 21 via the sheet carry-in path P1 of the post-processing apparatus B. The pages are stacked and stored in the order of the pages. In this mode, no sheet is guided to the first switchback transport path SP1 and the second switchback transport path (sheet processing path) SP2.

"Staple binding finish mode"
In this mode, the image forming apparatus A forms an image of a series of documents in the order from the first page to the nth page as in the above-described printout mode, and carries out from the main body discharge port 3 in a face-down state. Accordingly, the post-processing apparatus B retracts the buffer guide 26 of the sheet carry-in path P1 upward in FIG. 3 and moves the path switching piece 27 to the state of the solid line in FIG. As a result, the sheet sent to the sheet carry-in path P <b> 1 is guided to the paper discharge roller 25. Therefore, after the expected time that the leading edge of the sheet reaches the forward / reverse roller 30 of the stacking tray 29 based on the signal detected by the sheet discharge port 25a, the sheet conveyance control unit 64a moves the forward / reverse roller 30 from the upper standby position onto the tray. Then, the forward and reverse rollers are rotated clockwise in FIG. Next, the sheet conveyance control unit 64a drives the forward / reverse rotation roller 30 to rotate counterclockwise in FIG. 3 after the estimated time when the trailing edge of the sheet is carried onto the stacking tray 29. Then, the sheet that has entered from the paper discharge outlet 25a is switched back and conveyed onto the stacking tray 29 along the first switchback conveyance path SP1. By repeating this sheet conveyance, a series of sheets are stacked on the stacking tray 29 in a face-down state.

  Each time the sheets are stacked on the stacking tray 29, the control CPU 61 operates the side aligning plate 34b to align the width direction position of the sheets to be stacked. Next, the control CPU 61 operates the end-face stitching and stapling device 33 in response to the job end signal from the image forming apparatus A to bind the trailing edge of the sheet bundle stacked on the stacking tray 29. After this stapling operation, the control CPU 61 moves the rear end regulating member 32 that also serves as a bundle carrying-out means from the solid line position in FIG. 3 to the chain line position. Then, the staple-bound sheet bundle is carried out and stored on the first paper discharge tray 21. As a result, a series of sheets formed by the image forming apparatus A are stapled and stored in the first paper discharge tray 21.

"Sheet fold finish mode"
In this mode, the image forming apparatus A forms an image on a sheet in the order described with reference to FIG. Therefore, the post-processing apparatus B retracts the buffer guide 26 of the sheet carry-in path P1 upward in FIG. 3, and moves the path switching piece 27 to the state of the solid line in FIG. As a result, the sheet sent to the sheet carry-in path P <b> 1 is guided to the paper discharge roller 25. Therefore, the control CPU 61 stops the paper discharge roller 25 at the timing when the trailing edge of the sheet passes the path switching piece 27 with reference to the signal detected by the sheet sensor S1, and at the same time, sets the path switching piece 27 to the position of the broken line in FIG. Moving. Then, the paper discharge roller 25 is reversely rotated (counterclockwise in FIG. 3). Then, the sheet that has entered the sheet carry-in path P1 is reversed in the conveyance direction and is guided from the path switching piece 27 to the sheet entry path 35a. And it guides to the accumulation | aggregation guide 35b with the conveyance rollers 36 and 37 arrange | positioned in this path | route.

  The control CPU 61 moves the sheet leading edge regulating means 38 to the lowermost position Sh1 at the timing when the sheet is carried into the stacking guide 35b from the sheet entry path 35a (state shown in FIG. 11A). The control CPU 61 moves the position of the sheet leading edge regulating means 38 to an optimum position corresponding to the sheet length from the sheet size information (length in the conveying direction) from the image forming apparatus A and the position data stored in the RAM 63. . Then, the entire sheet is supported by the accumulation guide 35b. In this state, the control CPU 61 operates the aforementioned sheet side edge aligning means 39 to align the sheets in the width direction. (Note that this width-alignment alignment does not have to be performed on the first sheet, and does not have to be performed every time the sheet enters).

  Next, the control CPU 61 moves the sheet leading edge regulating means 38 to a position Sh3 where the sheet trailing edge enters the switchback entry path 35c described above. FIG. 11B shows this state, and the control CPU 61 moves the sheet leading edge regulating means 38 from the position data stored in the RAM 63 to a position Sh3 where the trailing edge of the sheet enters the switchback entry path 35c. Then, the rear end of the sheet supported by the accumulation guide 35b moves backward to the switchback entry path 35c. In this state, subsequent sheets are fed from the sheet entry path 35a onto the accumulation guide 35b, and the subsequent sheets are stacked on the preceding sheet. Then, the sheet leading edge regulating means 38 is moved from the Sh3 position to the Sh1 position in accordance with the carry-in of the succeeding sheet (the state shown in FIG. 11A).

  Next, the control CPU 61 operates the sheet side edge aligning means 39 in the state shown in FIG. 11A to align the loaded sheet and the sheet supported on the stacking guide. By repeating such an operation, the sheets formed with the image by the image forming apparatus A are aligned on the stacking guide 35b through the sheet entrance path 35a.

  Next, when receiving a job end signal, the control CPU 61 moves the sheet leading edge regulating means 38 to the position Sh2, and sets the center of the sheet to the binding position X. FIG. 12C shows this state, and the control CPU 61 sends a command signal for executing a stapling operation to the saddle stitching stapler 40 after moving the sheet leading edge regulating means 38 to Sh2. Then, the stapling device 40 staples one or more places in the center of the sheet.

  In response to the completion signal of the stapling operation, the control CPU 61 moves the sheet leading edge regulating means 38 to the position Sh1 and positions the sheet center at the folding position Y (state shown in FIG. 12D). Therefore, the sheet bundle is folded in the sequence shown in FIGS. 8A to 8D and the sheet bundle is carried out to the second paper discharge tray 22.

  In the present invention, the saddle stitching stapling device 40 is disposed at the binding position X on the stacking guide 35b. However, the sheet processing path is disposed in the order of the stacking guide, the binding position, and the folding position. The stacking guide unit, then the stapling device, and the sheet folding unit may be arranged downstream thereof. Further, it is possible to fold the sheet bundle and carry it out to the second paper discharge tray 22 without performing the binding process by the saddle stitching stapling device 40.

1 is an overall explanatory diagram of an image forming system according to the present invention. 1 is an overall explanatory view of a post-processing apparatus provided with a sheet folding apparatus according to the present invention. Detailed explanatory drawing which shows a part of post-processing apparatus of FIG. FIG. 3 is a detailed explanatory diagram of a sheet folding apparatus incorporated in the post-processing apparatus of FIG. 2. FIG. 2 is an explanatory diagram showing an image forming order in the apparatus of FIG. 1. It is explanatory drawing of the folding roll means of FIG. 4, (a) is sectional structure, (b) is explanatory drawing of a sheet | seat width direction plane. (A) is explanatory drawing of the drive mechanism of folding roll means, (b) is explanatory drawing of the drive mechanism of folding blade, (c) is structure explanatory drawing of a one-way clutch. FIGS. 3A and 3B are explanatory diagrams of a sheet bundle folding operation in the apparatus of FIG. 2, wherein FIG. 3A is a state diagram in which the sheet bundle is positioned and set at a folding position, FIG. 2B is an initial state diagram of the sheet bundle folding operation; Is a state diagram in which the sheet bundle is inserted into the nip position of the folding roll means, and (d) is a carrying out state diagram in which the sheet bundle is folded by the folding roll means. Explanatory drawing of the control structure in the system of FIG. FIG. 5 is an explanatory diagram illustrating a configuration of a sheet leading edge regulating unit in the apparatus of FIG. 4. FIGS. 5A and 5B are operation state explanatory diagrams of the sheet leading edge regulating unit in the apparatus of FIG. 4, in which FIG. 5A is a state in which the first sheet enters the stacking guide, and FIG. FIGS. 5A and 5B are operation state explanatory views of the sheet leading edge regulating means in the apparatus of FIG. 4, in which FIG. 5C is a state diagram for positioning the sheet bundle accumulated in the accumulation guide at a binding position, and FIG. The state figure which positions a bundle in a folding position.

Explanation of symbols

A Image forming apparatus B Post-processing apparatus P1 Sheet carry-in path SP1 First switchback conveyance path SP2 Second switchback conveyance path (sheet processing path)
MS shift means 21 first discharge tray 22 second discharge tray 23 carry-in port 24 carry-in roller 25 discharge roller 25a discharge port 26 buffer guide 27 path switching piece 29 first stacking unit (stacking tray)
32 Rear end regulating member 30 Forward / reverse roller 33 End face stapling device 35a Sheet entry path 35b Accumulation guide (accumulation guide means)
35c Switchback entry path 36 Conveying roller 37 Conveying roller 38 Sheet leading edge regulating means 38a Locking member 38b Grip member 38L Actuating solenoid 38S Energizing spring 38M Stepping motor 39 Sheet side edge aligning means 40 Saddle stitching staple device 45 Folding roll means 45a First One folding roll 45b Second folding roll 45c Clutch means 46 Folding blade 60 Post-processing control unit

Claims (8)

A sheet processing path for feeding a sheet from the carry-in entrance to a predetermined folding position;
Accumulation guide means for aligning the sheets, which are arranged at the folding position and sequentially supplied, in a bundle shape;
A sheet leading edge restricting means for restricting the position of the sheet placed on the stacking guide means arranged in the sheet processing path;
Shift means for moving the sheet leading edge regulating means along the sheet processing path;
Folding roll means for folding the sheet bundle arranged at the folding position and accumulated on the accumulation guide means;
A stapling unit that is arranged upstream of the folding roll unit and binds a bundle of sheets stacked on the stacking guide unit, and
The sheet processing path is
A sheet entry path for carrying sheets toward the accumulation guide means;
A switchback approach path for moving the rear end of the sheet supported by the stacking guide means backward by a predetermined amount upstream,
The switchback approach path is configured to be able to move the sheet supported by the stacking guide means to an overlap position where the rear end overlaps the sheet front end from the sheet entrance path,
The shifting means is
(1) When a sheet enters the accumulation guide means from the sheet entry path, the sheet rear end supported by the accumulation guide means is moved to the overlap position,
(2) When binding by the stapling means, the sheet supported by the stacking guide means is moved to the sheet binding position;
(3) When folding with the folding roll means, the sheet supported by the stacking guide means is moved to the folding position.
Thus, the sheet folding apparatus controls the position of the sheet leading edge regulating means. The sheet front end restricting means is disposed in the sheet processing path so as to be movable at least at the first, second, and third positions sequentially spaced from the upstream side to the downstream side,
The shift means is the sheet leading edge regulating means,
(1) positioning the sheet supported by the stacking guide means at the first position at the overlap position;
(2) positioning the sheet supported by the stacking guide means at the second position at the sheet binding position;
(3) The sheet folding apparatus according to claim 1, wherein the sheet supported by the stacking guide means is positioned at the folding position at the third position. The sheet folding apparatus according to claim 1, wherein the sheet processing path includes a switchback conveyance path that reverses a conveyance direction after conveying a sheet from a carry-in entrance in a predetermined direction. The sheet processing path is provided with sheet side edge aligning means for aligning sheets supported by the stacking guide means. The sheet side edge aligning means includes a pair of aligning plates engaged with the sheet side edges, and the aligning plate. And actuating means for moving them closer to and away from each other,
The operation means performs the alignment operation of the pair of alignment plates in a state where the sheet front end restricting means restricts the sheet supported by the stacking guide means to a sheet binding position or a folding position. 4. The sheet folding apparatus according to any one of items 3. The sheet processing path is formed in a curved or bent shape in which a sheet supported by the stacking guide means protrudes toward the switchback approach path and the stapling means and / or folding roll means. Item 5. The sheet folding device according to any one of Items 1 to 4. The sheet front end restricting means includes a locking member for engaging the front end of the sheet and a grip member for gripping the sheet, and the seat grip member releases the grip in conjunction with or in synchronization with the operation of the shift means. Item 6. The sheet folding device according to any one of Items 1 to 5. A sheet carry-in route having a carry-in entrance for sequentially carrying in sheets;
A first switchback conveyance path that branches off from the carry-in path and reverses the sheet conveyance direction;
A second switchback conveyance path disposed upstream of the first switchback conveyance path and branching from the sheet carry-in path to reverse the sheet conveyance direction;
A sheet folding device disposed in the second switchback conveyance path,
A post-processing apparatus, wherein the sheet folding apparatus includes the configuration according to any one of claims 1 to 6. An image forming apparatus for sequentially forming images on sheets;
A post-processing device that performs post-processing such as stapling, stamping, and punching on the sheet from the image forming apparatus,
An image forming system comprising the post-processing apparatus having the configuration according to claim 7.

Images