JP2010013206A - Sheet folding device and method, sheet treatment device mounted with sheet folding device, and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet folding device and method for enabling refolding to accurately apply a folding line while hardly causing the displacement of intermediate sheets during refolding, and to provide a sheet treatment device mounted with the sheet folding device, and an image forming system. <P>SOLUTION: The sheet folding device is provided for folding bunched sheets consisting of a plurality of stacked sheets at a desired folding line position. It includes a clamping means for clamping the bunched sheets interfolded at the folding line position as a boundary, and a thrusting means for thrusting the bunched sheets between a clamping position of the clamping means and the folding line position, moving the thrusting position from the clamping position of the clamping means to the folding line position, and thrusting the bunched sheets at the folding line position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a sheet folding apparatus and a sheet folding method that can be used as an optional apparatus of an image forming apparatus such as a copying machine, a printer, and a printing machine, and a sheet processing apparatus and an image forming system equipped with the sheet folding apparatus. .

2. Description of the Related Art In recent years, as an optional device of an image forming apparatus main body, a sheet processing apparatus that performs saddle stitching on a sheet on which an image has been formed, and then performs center folding on the basis of the binding position and transports the sheet outside the apparatus. Further, the folding function has been improved day by day, and a sheet processing apparatus having a folding function that can be folded out and unloaded without being subjected to the saddle stitching process is also proposed.

For example, Patent Document 1 discloses that a pair of folding rollers are arranged at a desired interval in the sheet unloading direction, folded in the middle with a pair of folding rollers upstream in the unloading direction, and then again with a pair of folding rollers downstream in the unloading direction. There has been disclosed a folding device that can surely form a fold by folding.

Further, Patent Document 2 moves along a folded portion of a sheet bundle that is folded in half and presses a crease. Similar to Patent Document 1, the additional folding effect is obtained by locally pressing the folded portion. The targeted technology is disclosed.
JP 2001-19269 A Japanese Patent Laid-Open No. 7-2426

However, in the case of Patent Document 1, as shown in FIG. 13, a pair of folding rollers are arranged upstream and downstream in the unloading direction, and after folding between the pair of upstream folding rollers, the folded portion of the sheet bundle is placed at the top. Further folding is performed by passing again between the nips of the pair of downstream folding rollers. In this configuration, even if there is a slight difference depending on the gap between the pair of folding rollers disposed in the carry-out direction with respect to the sheet width, there is an effect that the middle sheet is returned by the component force F2 of the pressing force F1 of the pair of folding rollers. As a result, the central portion of the folded sheet bundle is liable to bulge and misalign between the upstream and downstream folding roller pairs, and as a result, the downstream folding roller in a state in which the cover sheet and the middle sheet are misaligned as indicated by L1 in the drawing. It will pass through the pair, and it is easy to cause the problem that it cannot be folded correctly.

In the case of Patent Document 2, as shown in FIG. 14, the folded portion of the sheet bundle once folded is gradually and gradually folded from the near side to the far side. In this configuration, even if there is a slight difference as in the above-mentioned Patent Document 1 depending on the thickness of the sheet bundle, the inner sheet is gradually pushed out into a fan shape by the component force F6 of the pressing force F5 of the pair of folding rollers. As shown by L2 in the figure, the cover and the middle paper are misaligned, and it is easy to cause a problem that they cannot be folded correctly.

Accordingly, in view of the above-described problems, the present invention provides a sheet folding apparatus and a sheet folding method that can be folded accurately, in which the inner sheet is particularly difficult to shift with respect to the cover, and a sheet processing apparatus equipped with the sheet folding apparatus, It is an object to provide an image forming system.

In order to solve the above-described problem, a sheet folding apparatus according to the present invention is a sheet folding apparatus that folds a sheet bundle in which a plurality of sheets are stacked at a desired fold position, and is folded at the fold position. Pressing the sheet bundle between a clamping means that clamps the clamping means, a clamping position that the clamping means clamps, and the fold position, and moving the pressing position from the clamping position side of the clamping means toward the fold position side, Pressing means for pressing the crease portion.

Specifically, the sandwiching means comprises a pair of carry-out rollers that fold the two side portions that are substantially equidistant from each other at the crease location of the sheet bundle, fold them into two folds, and carry them out downstream. Includes an additional folding mechanism that refolds and folds the fold of the sheet bundle folded in two by the clamping means, and as the additional folding mechanism, a curved surface having a curved section in the clamping direction and a curvature of about 200 mm in radius. A curved plate-shaped member that forms a sheet, a pressing member that presses the curved surface of the curved plate-shaped member against the sheet surface of the sheet bundle, and the pressing member is moved along the sheet surface of the sheet bundle, The holding position of the sheet bundle by the member is constituted by moving means for moving from the holding position side of the holding means toward the fold position side.

In addition, as a sheet folding method for performing a folding process on a sheet bundle on which a plurality of sheets are stacked at a desired fold position, a bundle stacking process for stacking a plurality of sheets sequentially and stacking them in a bundle shape, A folding step of folding the accumulated sheet bundle at a desired crease location, a clamping step for clamping and holding the sheet bundle folded by the folding step, and a position between the clamping position and the crease location sandwiched in this clamping step Pressing the sheet bundle, moving the pressing position from the clamping position side toward the fold position side, and pressing the fold position, and in the additional folding process, the bi-folding means This is repeated a plurality of times from the holding position side toward the crease location side. In the folding step, the sheet bundle passes between the pair of carry-out rollers at the top so that the sheet bundle is folded and folded in two, and the sheet bundle is pinched by the pair of carry-out rollers in the pinching step. In the pressing step, the crease portion of the sheet bundle folded in half by the clamping means is refolded and formed again. Furthermore, in the pressing step, the pressing movement is repeated a plurality of times from the clamping position side toward the crease location side.

The sheet folding apparatus further includes a paper discharge port for sequentially carrying out the sheets, a processing tray for collecting the sheets from the paper discharge port in a bundle, and a stack tray for storing the sheet bundle carried out from the processing tray. The sheet processing apparatus is used as an option of an image forming apparatus that sequentially forms images on sheets to construct an image forming system.

According to the present invention, in a state in which the sheet bundle folded at the crease location is sandwiched, the crease location is pressed while moving the pressing position from the clamping position side toward the crease location side. There is no misalignment of the inner paper as in the folding device, and the folding process can be performed at an accurate crease portion.

Further, by using a curved plate member for the additional folding mechanism that constitutes the pressing means for pressing the crease location, it is possible to provide a compact apparatus that suppresses an increase in size of the apparatus. Further, by using this curved plate-like member, there is no possibility that the crease will be rubbed or shredded in the so-called additional fold when the fold is folded once.

The present invention will be described in detail below based on the preferred embodiments of the present invention shown in the drawings. FIG. 1 is an overall configuration diagram showing an image forming system including an image forming apparatus A and a sheet processing apparatus B according to the present invention, and FIG. 2 is an explanatory diagram of a detailed configuration of the sheet processing apparatus B.

[Configuration of image forming system]
The image forming system shown in FIG. 1 includes an image forming apparatus A and a sheet processing apparatus B. Then, the paper inlet 23a of the sheet processing apparatus B is connected to the paper discharge port 3 of the image forming apparatus A, and the sheet on which the image is formed by the image forming apparatus A is subjected to post-processing such as stapling and half-folding by the sheet processing apparatus B. The stack tray 21 and the saddle tray 22 are accommodated.

[Configuration of Image Forming Apparatus A]
First, the image forming apparatus A is configured to send a sheet from the paper feeding unit 1 to the image forming unit 2, print the sheet on the image forming unit 2, and then discharge the sheet from the paper 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 specified 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 paper discharge port 3. 9 is a circulation path. A sheet printed on the front side from the fixing device 8 is reversed on the front and back via the 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 print path. The sheet printed on both sides in this way is turned upside down by the switchback path 10 and then carried out from the paper 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 14. This image data is digitally processed by the image processing unit, for example, and then transferred to the data storage unit 17 to send an image signal to the laser emitter 5. 15 is a document feeder, which is a feeder device that feeds document sheets stored in the stack tray 16 to the platen 12.

The image forming apparatus A having the above-described configuration is provided with a control unit (controller) 150 shown in FIG. 12, and image forming conditions such as sheet size designation, color / monochrome printing designation, print number designation, single-sided / double-sided printing from the control panel 18. Printing conditions such as designation and enlargement / reduction printing 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 such as single-sided / double-sided printing, enlargement / reduction printing, and monochrome / color printing described above. As the post-processing conditions, for example, “print-out mode”, “binding finish mode (multi-staple mode, non-multi-staple mode)”, “booklet finishing mode”, or the like is selected.

[Configuration of Sheet Processing Apparatus B]
Next, the sheet processing apparatus B receives the sheet on which the image has been formed from the sheet discharge port 3 of the image forming apparatus A, and (i) whether the sheet is accommodated in the stack tray 21 (the aforementioned “print-out mode”) or ( ii) After aligning sheets from the sheet discharge outlet 3 in a bundle and stapling, the sheets are stored in the stack tray (first stack tray) 21 (the above-mentioned “binding finish mode”), or (iii) sheet discharge After aligning the sheets from the mouth 3 in a bundle and stapling the center, the sheet is folded into a booklet and stored in the saddle tray (second stack tray) 22 (the above-mentioned “booklet finishing mode”). It is configured as follows.

The casing (exterior cover) 20 of the sheet processing apparatus B is provided with a carry-in port 23a, and this carry-in port 23a is connected to the paper discharge port 3 of the image forming apparatus A. The casing 20 is provided with a first processing unit BX1 for aligning and collecting sheets from the carry-in entrance 23a and binding and finishing, and a second processing unit BX2 for collecting and collecting sheets from the carry-in entrance 23a and finishing the booklet. It has been. A first carry-in route P1 is provided between the first processing unit BX1 and the carry-in port 23a, and a second carry-in route P2 is provided between the second process unit BX2 and the carry-in port 23a. These sheets are distributed and guided to the first processing unit BX1 and the second processing unit BX2. The carry-in entrance 23 is provided with a carry-in roller 25, a sheet sensor S1, and a path switching means (flapper member) 24 that distributes sheets to the first or second carry-in paths P1 and P2.

A buffer path P3 is provided between the punch unit 60 and the processing tray 29 in the first transport path P1. This buffer path P3 is provided for temporarily retaining the succeeding sheet sent to the carry-in port 23a during a post-processing operation such as stapling in a sheet bundle that is aligned and stacked on the processing tray. Therefore, the buffer path P3 is branched and arranged in the first carry-in path P1 in the vertical direction of the casing 20, as shown in FIG. Then, the sheet from the first carry-in path P1 is switched back and stays in this path. Accordingly, when the edge binding process is performed on the sheet bundle that has been aligned and stacked on the processing tray 29, the subsequent sheet sent to the carry-in entrance 23a is temporarily retained, and the processing sheet on the processing tray 29 is unloaded, and then in this path. The subsequent sheets can be transferred to the processing tray 29.

The first carry-in path P1 is disposed substantially horizontally in the upper part of the apparatus housing constituted by the casing 20, and the first processing unit BX1 is disposed downstream of the first carry-in path P1, and the stack tray 21 is disposed downstream thereof. Is arranged. The second carry-in path P2 is arranged substantially vertically in the lower part of the casing 20, and a second processing unit BX2 for performing a saddle stitching process and a middle folding process on the sheet bundle is arranged downstream of the second carry-in path P2. The saddle tray 22 is disposed on the downstream side. A punch unit 60 is disposed between the carry-in port 23a and the first processing unit BX1 in the first carry-in path P1, and between the second process unit BX2 and the saddle tray 22 in the second carry-in path P2. Is provided with a trimmer unit 90.

In the following, the process while the sheet sent to the second carry-in path P2 is carried out to the saddle tray 22 in FIG. 2 will be described in detail.

[Configuration of Second Processing Unit BX2]
As described above, the second processing unit BX2 includes the stacking guide 45 disposed in the second carry-in path P2, the saddle stitching unit 40 disposed in the stacking guide 45, and the sheet folding device 44. .

[Integration guide 45]
The stacking guide 45 is continuously arranged on the downstream side of the second carry-in path P2, and is configured to sequentially stack and store sheets from the carry-in entrance 23a in a standing posture. In particular, the illustrated accumulation guide 45 is arranged in a substantially vertical direction so as to cut the casing 20 vertically, and is configured to accumulate sheets in a standing position, thereby configuring the apparatus in a compact and compact manner. Further, the illustrated accumulation guide 45 is constituted by a guide plate bent at the center, and this accumulation guide 45 is formed in a length shape that accommodates the maximum size sheet therein, and includes a saddle stitching unit 40 and a folding processing mechanism 44 described later. It is configured in a curved or bent shape so as to protrude to the arrangement side. The stacking guide 45 is provided with a leading end stopper 43 for regulating the leading end of the sheet, and the leading end stopper 43 is moved in accordance with the sheet size (length in the paper discharge direction).

[Saddle stitching unit 40]
A saddle stitching unit 40 is disposed in the above-described stacking guide 45, and the center portion of the sheet bundle that is aligned and stacked on the stacking guide 45 is stapled. The structure is demonstrated based on Fig.11 (a) (b). The saddle stitching unit 40 includes a driver 70 and a clincher 75. The driver 70 includes a head member 70a for inserting staples into a sheet bundle set at the binding position, a cartridge 71 containing the staples, a drive cam 77, and a staple motor MD for driving the drive cam 77. Has been. As shown in FIG. 11B, the driver 70 has a driver member 72, a former 73, and a bending block 74 built in the vertical direction in a head member 70a of the frame. The driver member 72 and the former 73 are slidably supported by the head member 70a so as to reciprocate up and down between the top dead center and the bottom dead center, and the bending block 74 has a straight staple. It is fixed to the head member 70a as a mold that can be bent into a letter shape.

With such a configuration, the driver member 72 and the former 73 built in the head member 70a are rotated by the staple motor MD so that the drive cam 77 moves the drive lever 76 from the upper dead center to the lower lower dead center via the accumulating spring. Press to. As the drive lever 76 is lowered, the driver member 72 and the former 73 connected thereto are moved from the top dead center to the bottom dead center. The driver member 72 is constituted by a plate-like member so as to push down the back portion of the staple needle bent in a U-shape, and the former 73 is constituted by a U-shaped member as shown in FIG. The staple is folded in a U-shape with the block 74. That is, the staples are supplied from the cartridge 71 to the bending block 74, and the linear staples are press-formed between the former 73 and the bending block 74 in a U-shape, and then bent into the U-shape. When the driver member 72 pushes the staple staples toward the sheet bundle vigorously, the needle is inserted into the sheet bundle, and the needle tip that protrudes from the back side of the sheet bundle is bent inward by the clinchers 75a1 and 75a2, and staple processing is performed. Is supposed to do.

[First Example of Folding Device 44]
As shown in FIG. 2, the folding processing device 44 folds the sheet bundle at the fold position arranged on the downstream side of the saddle stitching unit 40 and folds both side portions that are substantially equidistant from each other at the fold position. A folding means 46 for conveying the sheet bundle downstream and temporarily holding the sheet bundle during additional folding, which will be described later, and a folding blade 47 for inserting the sheet bundle at the nip position of the folding means 46; In addition, an additional folding mechanism 48 for refolding the folded portion of the sheet bundle folded in half by the bifolding means 46, and a sheet bundle additionally folded by the additional folding mechanism 48 are received and transported to the saddle tray 22. It is comprised with the carrying-out means 49.

[Folding means 46]
The two-folding means 46 is composed of rolls 46a and 46b that are in pressure contact with each other, and each roll is formed to have a substantially maximum sheet width.
The pair of folding rolls 46a and 46b are formed of a material having a large coefficient of friction such as a rubber roller. This is because the sheet is transferred in the rotational direction while being bent by a soft material such as rubber, and may be formed by lining the rubber material. The folding rolls 46a and 46b are formed in an uneven shape, and a gap is formed in the sheet value width direction. This gap is arranged so as to coincide with the unevenness of the folding blade 47 described later, and consideration is given so that the tip of the folding blade can easily enter between the roll nips. In other words, the pair of folding rolls 46a and 46b that are in pressure contact with each other are formed in a concavo-convex shape having a gap in the sheet width direction, and the stapled portion of the sheet and the folding blade 47 similarly formed in the concavo-convex shape in this gap. The cutting edge enters.

  Next, the operation of folding the half-folded sheet with the bi-folding means 46 will be described with reference to FIGS. The pair of folding rolls 46a and 46b are positioned on the curved or bent protruding side of the stacking guide 45, and a folding blade 47 having a knife edge is provided at a position facing the sheet bundle SH supported by the stacking guide 45. It has been. The folding blade 47 is supported by the apparatus frame so as to be able to reciprocate between the standby position in FIG. 3A and the nip position in FIG.

  Therefore, the sheet bundle SH supported by the stacking guide 45 in a bundle shape is locked to the leading end stopper 43 (see FIG. 2) in the state shown in FIG. Positioned. Upon obtaining the set end signal of the sheet bundle SH, the drive control means (sheet bundle folding operation control unit 164d described below; the same applies hereinafter) turns off the clutch means CL.

  Accordingly, the drive control means 164d moves the folding blade 47 from the standby position toward the nip position at a predetermined speed. Therefore, in the state of FIG. 3B, the sheet bundle SH is bent by the folding blade 47 and inserted between the rolls. At this time, the folding rolls 46 a and 46 b are driven and rotated continuously with the sheet moved by the folding blade 47. The drive control means 164d stops the blade drive motor (not shown) after the expected time for the sheet bundle to reach the desired nip position, and stops the folding blade 47 at the position shown in FIG. Before and after this, the drive control means 164d switches the clutch means CL to the ON state and drives and rotates the folding rolls 46a and 46b. Then, the sheet bundle SH is sent out in the feeding direction (left side in the figure). Thereafter, the drive control means 164d moves and returns the folding blade 47 located at the nip position to the standby position in parallel with the feeding of the sheet bundle SH by the folding rolls 46a and 46b in the state shown in FIG.

  When the sheet bundle SH folded in this way is first engulfed between the pair of folding rolls 46a and 46b, the sheet contacting the roll surface is not drawn between the rolls by the rotating roll. That is, since the folding rolls 46a and 46b rotate following the inserted (pushed) sheet, only the sheet in contact with the roll will not be wound first. Further, since the roll follows and rotates following the inserted sheet, the roll surface and the sheet in contact with the roll are not rubbed, and the image is not rubbed.

[Increase folding mechanism 48]
Next, the additional folding process by the additional folding mechanism 48 will be described with reference to FIG. In the figure, 48a is an additional folding roller, 48b is a moving guide, 48c is a support member that supports the folding roller 48a so as to be movable, and 48d is an apparatus frame that supports the sheet bundle SH pressed by the additional folding roller 48a. It is the support plate fixed to.

Therefore, an additional folding method by the additional folding mechanism 48 will be described. First, as shown in FIG. 5A, a sheet bundle SH obtained by folding the two side portions, which are approximately equidistant from each other by the above-described bi-folding means 46, is folded and unfolded by the above-described bi-folding means 46. The rear side in the unloading direction is held by the two-folding means 46a and 46b before 49b and is in a temporarily stopped state. The additional folding roller 48a is retreated together with the moving guide 48b by a lifting mechanism (not shown) so as not to prevent the carry-out of the sheet bundle SH until the temporary stop state is reached.

Then, in a state where the sheet bundle SH is temporarily stopped at the position shown in the drawing, the additional folding roller 48a presses and holds the vicinity of the bi-folding means 46a, 46b side of the sheet bundle SH on the support plate 48d, and the additional folding roller 48a The sheet bundle SH moved from the holding position toward the unloading means 49a, 49b and folded by the two-folding means 46a, 46b as shown in FIG.

[Second Embodiment of Folding Device 44]
Although the folding processing device 44 of the first embodiment described above is capable of performing additional folding processing at an accurate crease location without causing misalignment of the intermediate paper, an additional folding roller 48a as shown in FIG. 10 (a). In the state of x3 in the figure where the additional folding roller 48a overruns to the position of x4 in the figure and the sheet bundle SH is subjected to an oblique force as shown by the arrows in the figure. , Scratches on the sheet surface, especially in the case of thin sheets, there are defects such as tearing, etc., and the following problems are also eliminated, the inner paper is not displaced, and additional folding processing is performed at the exact crease location A second embodiment that can be performed will be described with reference to FIGS.

5 and 6 show an image forming system and a sheet processing apparatus corresponding to the above-described FIGS. 1 and 2, and the configuration other than the folding processing apparatus 44 shown in FIG. 5 is the same as that in FIGS. Omitted.

Accordingly, the folding processing device 44 will be described with reference to FIGS. 7 and 8 are cross-sectional views of the folding processing apparatus 44, FIG. 7 is a front cross-sectional view at the YY position of the side surface shown in FIG. 8, and FIG. 8 is a side cross-sectional view at the XX position of the front surface shown in FIG. Each figure is illustrated.

In the figure, 48a is an additional folding roller, 48b is a moving guide, 48c is a support member that supports the folding roller 48a so as to be movable, and 48d is an apparatus frame that supports the sheet bundle SH pressed by the additional folding roller 48a. A support plate 48e fixed to the curved plate-like member that is pressed by the additional folding roller 48a and directly holds the sheet bundle SH against the support plate 48d, and 48g reciprocates the additional folding roller 48a back and forth along the movement guide 48b. A timing belt, 48f is a pulse motor capable of forward and reverse rotation that drives the timing belt 48g back and forth, a drive motor such as a DC motor with an encoder, and 48h is an elevating support frame that supports the additional folding roller 48a and the curved plate member 48e, 48i Is a curved plate formed on the lifting support frame 48h A slit groove 48 slidably supports the material 48 e, 48 j is an urging spring that urges the support 48 c downward and presses the folding roller 48 a against the sheet bundle SH, and 48 k supports the support 48 c movably up and down. A moving frame for moving and supporting the additional folding roller 48a along the moving guide 48b, FL is supported by an elevating mechanism (not shown) so that the elevating support frame 48h can be moved up and down, and the additional folding roller 48a and the curved plate member 48e are moved from the upper retracted position. This is an apparatus frame that moves up and down to a position necessary for additional folding according to the bundle thickness of the sheet bundle SH.

An elevating support frame 48h supported by the elevating mechanism (not shown) with respect to the apparatus frame FL is an upper retreat position that does not hinder the movement of the folded sheet bundle SH carried out by the above-described bifold rollers 46a and 46b. And the distance d to the support plate 48d is moved up and down based on information of the image forming apparatus A.

Next, the additional folding operation of the folding processing device 44 will be described with reference to FIG. First, as shown in FIG. 5A, a sheet bundle SH obtained by folding the two side portions, which are approximately equidistant from each other by the above-described bi-folding means 46, is folded and unfolded by the above-described bi-folding means 46. The rear side in the unloading direction is held by the two-folding means 46a and 46b before 49b and is in a temporarily stopped state. Note that the curved plate-like member 48e is held at the retracted position above the sheet support surface of the support plate 48d by a distance d so as not to prevent the sheet bundle SH from being carried out until the temporary stop state is reached.

Then, a plurality of sheets are sequentially stacked by the stacking guide 45 shown in FIG. 6 and stacked into a bundle (bundle stacking process), and the sheet bundle SH is approximately equal at the desired fold position by the bi-folding means 46a and 46b. The both side portions at a distance are overlapped and folded together (folding step), and the both side portions of the sheet bundle SH folded by the two folding means 46a and 46b are held (holding step) and shown in FIG. Paused at position. In this state, the curved plate member 48e is lowered together with the additional folding roller 48a, and presses and clamps the vicinity of the folding means 46a and 46b side of the sheet bundle SH on the support plate 48d. As shown in FIG. 7B, the sheet bundle SH is further folded from the state shown in FIG. 5A, and the curved plate member 48e is swollen against the rear portion of the sheet bundle SH in accordance with the movement of the additional folding roller 48a. The pressing point is gradually moved while suppressing the sheet folding, and the sheet bundle SH folded by the bi-folding means 46a and 46b is refolded again so that the inner sheet does not always shift as shown in the state of FIG. Processing (additional folding process) can be performed. Note that the additional folding process may be repeated as appropriate.

As a result, as shown in FIG. 10B, the curved plate-like member 48e securely cuts the sheet bundle SH so as to be rubbed against the sheet surface of the sheet bundle SH or to be broken even in the case of a thin sheet. In this way, additional folding processing can be performed at an accurate crease portion without causing the middle paper to be displaced. If the curvature R of the curved plate-like member 48e is about 200 mm, the sheet bundle SH can be further folded while suppressing the rear portion restraining bulge as described above.

[Description of control configuration]
The control configuration of the above-described image forming apparatus will be described with reference to the block diagram of FIG. The image forming system shown in FIGS. 1 and 5 includes a control unit (hereinafter referred to as “main body control unit”) 150 of the image forming apparatus A and a control unit (hereinafter referred to as “post-processing control unit”) 160 of the sheet processing apparatus B. Yes. The main body control unit 150 includes an image formation control unit 151, a paper feed control unit 152, and an input unit 153. Then, “image formation mode” and “post-processing mode” are set from the control panel 18 provided in the input unit 153. 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 150 controls the image forming control unit 151 and the paper feed control unit 152 according to the set image forming conditions to form an image on a desired sheet, and then sequentially discharges the sheet from the main body discharge port 3. To do.

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”, “edge-binding finishing mode”, or “sheet bundle folding finishing mode”. Therefore, the main body control unit 150 transfers the finishing mode of the post-processing, the number of sheets, the number of copies information, and the binding mode (single binding at one location or binding at two or more locations) information to the post-processing control unit 160. At the same time, the main body control unit 150 transfers a job end signal to the post-processing control unit 160 every time image formation is completed.

[Post-processing control unit]
The post-processing control unit 160 includes a control CPU 161 that operates the sheet processing apparatus B in accordance with a designated finishing mode, a ROM 162 that stores an operation program, and a RAM 163 that stores control data. The control CPU 161 performs processing of “sheet conveyance control unit 164a” for conveying the sheet sent to the carry-in entrance 23a, “punch control unit 164p” for punching punch holes in the sheet from the image forming apparatus A, and processing. A “sheet stacking operation control unit 164 b” that controls the stacking of sheets on the tray 29, an “end binding operation control unit 164 c” that performs binding processing on the sheet bundle stacked on the processing tray 29, and the stacking guide 45. The “folding control unit 164d” that performs the folding process on the sheet bundle and the “trimmer control unit 164t” that trims and aligns the sheet bundle after the folding process.

[Folding processing control unit 164d]
The folding processing control unit 164d controls the carrying-out operation of the sheet bundle SH of the two-fold rollers 46a and 46b described above based on the information that the half-folding processing is selected on the control panel 18 of the control unit 150 of the image forming apparatus. Then, the carrying-out operation of the bi-fold rollers 46a and 46b is temporarily stopped, and when the stop signal is received, the elevating support frame 48h (see FIG. 7) is lowered to the uppermost surface of the sheet bundle SH, and the support 48c and the moving frame shown in FIG. The additional folding roller 48a supported by the support 48c is pressed against the sheet bundle SH by an urging spring 48j provided between the sheet 48 and 48k. The drive motor 48f is operated in the pressed state, and the additional folding roller 48a is controlled to move from the side of the double folding rollers 46a and 46b toward the folding portion of the sheet bundle SH.

In the above description of the embodiment, the folding processing device 44 explained the middle folding process as the folding of the sheet bundle SH. However, Z folding can be performed by performing the folding in two steps. The folding processing device 44 can also be used as a single unit. In this case, the sheet bundle is manually folded in advance and then fed into the above-mentioned folding means 46a and 46b, and then further folded. Can be implemented.

1 is an overall configuration diagram of an image forming system (first embodiment) according to the present invention. FIG. 2 is an overall configuration diagram of a sheet processing apparatus (sheet handling apparatus) in the system of FIG. 1. FIG. 3 is an explanatory diagram of a folding operation of the sheet folding apparatus of FIG. 2. Explanatory drawing of the additional folding operation | movement of the sheet folding apparatus of FIG. 1 is an overall configuration diagram of an image forming system (second embodiment) according to the present invention. FIG. 6 is an overall configuration diagram of a sheet processing apparatus (sheet handling apparatus) in the system of FIG. 5. FIG. 6 is a front sectional view of the sheet folding apparatus of FIG. 5. FIG. 6 is a side sectional view of the sheet folding apparatus of FIG. 5. Explanatory drawing of the additional folding operation | movement of the sheet folding apparatus of FIG. FIG. 10 is an enlarged view of a main part of the additional folding operation in FIGS. 4 and 9. FIGS. 7A and 7B are explanatory diagrams of a saddle stitch unit in the apparatus of FIGS. 2 and 6, in which FIG. FIG. 6 is a block diagram of a control configuration in the image forming system of FIGS. 1 and 5. The additional folding state figure in the conventional sheet folding apparatus. The additional folding state figure in the other conventional sheet folding apparatus.

Explanation of symbols

A Image forming apparatus B Sheet processing apparatus 40 Saddle stitching unit 44 Sheet folding apparatus 46 Nipping means 46a, 46b Folding rollers (a pair of folding rollers)
48 Pressing means (additional folding mechanism)
48a Additional folding roller 48e Curved plate member 49 Unloading means 49a, 49b Unloading roller pair

Claims (10)

In a sheet folding apparatus that folds a sheet bundle in which a plurality of sheets are stacked at a desired fold position,
Clamping means for clamping the sheet bundle folded at the crease location;
The sheet bundle is pressed between the clamping position held by the clamping means and the crease position, the pressing position is moved from the clamping position side of the clamping means toward the fold position side, and the fold position is pressed. Means,
A sheet folding apparatus comprising: The clamping means is composed of a pair of carry-out rollers that folds each side part at approximately equal distance from each other at the crease part of the sheet bundle, folds it into two folds, and carries it out downstream.
The sheet folding apparatus according to claim 1, wherein the pressing unit includes an additional folding mechanism that refolds and folds the fold of the sheet bundle folded in two by the clamping unit. The additional folding mechanism is
A curved plate-like member having a curved cross section in the clamping direction;
A pressing roller for pressing the curved surface of the curved plate-shaped member against the sheet surface of the sheet bundle;
Moving means for moving the pressing roller along the sheet surface of the sheet bundle, and moving the holding position of the sheet bundle by the plate-shaped member from the holding position side of the bi-folding means toward the fold position side;
The sheet folding apparatus according to claim 2, comprising: The sheet folding apparatus according to claim 3, wherein the curved plate-like member is formed by forming a curved surface having a radius of curvature of about 200 mm. The sheet folding apparatus according to any one of claims 1 to 3, wherein the sheet folding device is formed by folding the fold portion to form a middle fold or a Z fold. In a sheet folding method in which a sheet bundle in which a plurality of sheets are stacked is folded at a desired fold position,
A bundle stacking process in which a plurality of sheets are sequentially stacked and stacked in a bundle;
A folding step of folding the sheet bundle accumulated by the bundle accumulation step at a desired fold position;
A sandwiching step of sandwiching and holding the sheet bundle folded by the folding step;
A pressing step in which the sheet bundle is pressed between the nip position and the fold position held in the clamping process, the pressing position is moved from the nip position side toward the fold position side, and the fold position is pressed; ,
A sheet folding method comprising: In the folding step, between the pair of carry-out rollers, the fold portion of the sheet bundle is passed to the head, folded and folded into two,
In the clamping step, the sheet bundle is clamped by the pair of carry-out rollers,
The sheet folding method according to claim 6, wherein the pressing step forms a fold portion of the sheet bundle that is folded in half by the sandwiching means, and then folds and forms it again. 8. The sheet folding method according to claim 6, wherein, in the pressing step, the pressing movement is repeatedly performed a plurality of times from the clamping position side toward the crease position side. 9. A paper discharge port for sequentially carrying out the sheets;
A processing tray for collecting sheets from the paper discharge port in a bundle;
A stack tray for storing a bundle of sheets carried out from the processing tray;
In a sheet processing apparatus provided with a sheet folding apparatus that performs a folding process on a sheet bundle to be carried out on the stack tray at a desired fold position,
A sheet processing apparatus comprising the structure according to any one of claims 1 to 5. An image forming apparatus for sequentially forming images on sheets;
A sheet processing apparatus that performs a middle folding process on a sheet bundle in which a plurality of sheets from the image forming apparatus are stacked at a desired middle fold position,
An image forming system comprising the sheet processing apparatus having the configuration according to claim 9.