JP2003073027A - Paper after-processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily move a central part of a bundle of paper having a thickness to a holding position by a pair of middle folding rollers, and to reduce the driving load on a middle holding knife in pressing the central part of the bundle of paper having the thickness by the middle folding knife. SOLUTION: In this paper after-processing device wherein the central part in the delivering direction of the bundle of paper S delivered on a paper loading part 64 is pushed to the holding position of at least a set of middle folding roller pairs 671 while being pressed by the middle folding knife 661 of a paper pressing means to perform the middle folding processing onto the bundle of paper Sa, a holding gap δ at standby of the middle folding roller pairs 671 is variably determined corresponding to the number of sheets of the bundle of paper Sa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine,
Sheets discharged after image formation from an image forming apparatus such as a printer, a facsimile, and a multifunction machine having these functions are sequentially taken into a sheet post-processing apparatus, and post-processing such as binding processing and folding processing is performed on this sheet. The present invention relates to a sheet post-processing apparatus having a function of ejecting to a sheet ejection unit.

[0002]

2. Description of the Related Art A sheet post-processing device called a finisher is used as a device for collating a plurality of image-recorded sheets discharged from an image forming apparatus for each copy number and binding them by stapling means.

This paper post-processing apparatus is connected in function to the main body of an image forming apparatus such as a copying machine or a printer, and is driven in response to a sequence operation of a copying or printing process.

Therefore, for an image forming apparatus capable of processing the image forming process at high speed, a sheet post-processing apparatus capable of high speed processing capable of following the processing speed and performing its function is required. It

Regarding such a sheet post-processing apparatus, JP-A-60-142359 and JP-A-60-15846 have already been proposed.
No. 3, 62-239169, and JP-A-62-28.
8002, 63-267667, JP-A-2-27
6691, JP-A-8-319054, JP-B-5-4
It is disclosed in each publication of 1991.

The bookbinding apparatus disclosed in Japanese Patent Application Laid-Open No. 60-183459 has a cover feeding device and performs bookbinding finishing such as punching or stapling after superposing a copy sheet group and a cover sheet.

JP-A-6-72064 and 7-1874
No. 79 and No. 8-192951 are sheet post-processing devices having a saddle stitching function.

[0008]

The conventional sheet post-processing apparatus has the following problems.

(1) The central portion of the sheet bundle conveyed on the sheet stacking portion in the conveying direction is pushed into the sandwiching position of at least one pair of center folding rollers while being pressed by the center folding plate member of the sheet ejecting means, In a sheet post-processing device that performs half-fold processing of a bundle of sheets, when a bundle of sheets with a large number of sheets and a large thickness is pushed into the sandwiching position of the pair of center folding rollers by the center folding plate member, the state where the pair of center folding rollers is pressed and clamped If so, it is difficult for the center-folded portion of the sheet bundle to enter the nipping position of the center-folding roller pair.

(2) When a thick sheet bundle is pushed into the sandwiching position of the center folding roller pair by the center folding plate member, a large load is applied to the center folding plate member when the center folding roller pair is pressed and clamped. Takes.

[0011]

The above-mentioned problems in the center folding process are solved by the following sheet post-processing device.

(1) The central portion of the bundle of sheets conveyed on the sheet stacking portion in the conveying direction is pushed into the sandwiching position of at least one pair of center folding rollers while being pressed by the center folding plate member of the sheet ejecting means, A sheet post-processing device for performing a center-folding process for a sheet bundle, wherein a sandwiching gap of the pair of center-folding rollers during standby is variably set according to the number of the sheet bundle.

(2) The central portion of the sheet bundle conveyed on the sheet stacking portion in the conveying direction is pushed into the sandwiching position of at least one pair of center folding rollers while being pressed by the center folding plate member of the sheet ejecting means, In a sheet post-processing device for center-folding a sheet bundle, when the center portion of the sheet bundle in the conveying direction is pushed by the center-folding plate member into the sandwiching position of the center-folding roller pair, the center-folding roller pair is Following the conveyance of the sheet bundle, it is driven to rotate, and after the center folding plate member is pulled out from the sandwiching position of the center folding roller pair, rotation drive is started after a predetermined time corresponding to the number of the sheet bundle, A sheet post-processing device that discharges the sheet bundle.

(3) The central portion of the sheet bundle conveyed on the sheet stacking portion in the conveying direction is pushed into the holding position of at least one pair of center folding rollers while being pressed by the center folding plate member of the sheet ejecting means, In a sheet post-processing device for center-folding a bundle of sheets, a first drive unit that moves the center-folding plate member forward and backward, a second drive unit that rotates the center-folding roller pair, and a center-folding roller pair are supported. Third driving means for swinging the supporting member to allow the nipping gap of the center folding roller pair, and control means for controlling the driving of the first driving means, the second driving means, and the third driving means. The sheet post-processing apparatus, wherein the control unit variably sets the sandwiching gap of the center folding roller pair during standby in accordance with the number of sheets of the sheet bundle.

(4) The central portion of the sheet bundle conveyed on the sheet stacking portion in the conveying direction is pushed into the holding position of at least one pair of center folding rollers while being pressed by the center folding plate member of the sheet ejecting means, In a sheet post-processing device for center-folding a bundle of sheets, a first drive unit that moves the center-folding plate member forward and backward, a second drive unit that rotates the center-folding roller pair, and a center-folding roller pair are supported. And a third driving means for swinging the supporting member, wherein the control means for controlling the driving of the third driving means supports the swingable swinging member driven by the third driving means. The holding gap of the pair of center folding rollers is variably set according to the number of sheets of the sheet bundle by being pressed against the abutting portion of the member, and the sheet bundle thicker than the set maximum holding gap is set to the middle portion. A pair of folding rollers When passing through the gap, with the swinging member stopped at the maximum holding gap, the abutting portion is separated from the pressure contact position, and the center folding roller pair is spread by the sheet bundle to swing. A sheet post-processing device characterized by the above.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a sheet post-processing apparatus of the present invention will be described with reference to the accompanying drawings.

[One Embodiment of Image Forming Apparatus] FIG. 1 is an overall configuration diagram of an image forming system including an image forming apparatus main body A, an image reading apparatus B, and a sheet post-processing apparatus (hereinafter referred to as a post-processing apparatus) C. is there.

The image forming apparatus main body A has a charging unit 2, an image exposing unit (writing unit) 3, a developing unit 4, and a transfer unit 5 around a rotating image carrier (hereinafter referred to as a photoconductor) 1.
It has an image forming unit in which A, a charge eliminating unit 5B, and a cleaning unit 6 are arranged. The image forming unit uniformly charges the surface of the photoconductor 1 by the charging unit 2 and then performs exposure scanning based on the image data read from the original by the laser beam of the image exposing unit 3 to form a latent image. The latent image is reversely developed by the developing means 4 to form a toner image on the surface of the photoconductor 1.

The sheet S fed from the sheet storage means 7A is sent to the transfer position. Transfer means 5A at the transfer position
Thus, the toner image is transferred onto the sheet S. After that, the charge S on the back surface of the sheet S is erased by the charge removing unit 5B to be separated from the photoconductor 1, and the sheet S is transported by the intermediate transport unit 7B and subsequently heated and fixed by the fixing unit 8 and then the sheet discharge unit 7 is discharged.
Emitted from C.

When images are formed on both sides of the paper S,
The sheet S heated and fixed by the fixing unit 8 is branched from the normal sheet discharge path by the conveyance path switching plate 7D, switched back and turned upside down in the reversing conveyance section 7E, and then passes through the image forming section again to return the sheet. Form an image on the back of S,
After passing through the fixing unit 8, the paper is ejected from the paper ejection unit 7C to the outside of the apparatus. The paper S discharged from the paper discharge unit 7C is processed by the post-processing device C.
Is sent to the receiving section 11 of.

The surface of the photoreceptor 1 after the image processing is cleaned by the cleaning means 6 to remove the developer remaining on the surface, and the surface is prepared for the next image formation.

On the upper part of the image forming apparatus main body A, an image reading apparatus B equipped with an automatic original feeding apparatus of a moving original reading type is installed.

[Structure of Paper Post-Processing Apparatus] The post-processing apparatus C connected to the image forming apparatus main body A includes an entrance conveying section 10, a shift processing section 20, a binding processing section 30, a stapling means (binding means) 40, and a cover sheet feeding. It is composed of a paper unit 50, a center folding processing unit 60, and a paper discharge unit 80.

The entrance transport unit 10 transports the sheet S discharged from the image forming apparatus main body A to each processing unit. The shift processing section 20 shifts the sheet S conveyed from the entrance conveyance section 10 into a shift process and discharges the sheet S to an elevating and lowering paper tray 82 described later. The binding processing unit 30 stacks the sheets S conveyed from the entrance conveyance unit 10 and performs saddle stitching processing or edge binding processing by a stapling unit 40 described below. The center folding processing unit 60 folds the center portion of the sheet S in the sheet transport direction, performs center folding processing, and discharges the sheet S to a lower sheet discharge tray 83 described later. The cover sheet feeding section 50 feeds a cover sheet (hereinafter referred to as a cover sheet) K and conveys it to the shift processing section 20 or the binding processing section 30.

The paper discharge unit 80 includes an upper paper discharge table 81 for directly discharging and accommodating the paper S discharged from the image forming apparatus main body A via the entrance conveyance unit 10 without post-processing, and a shift process. Further, it has an elevating and lowering paper ejection tray 82 for accommodating the end-stitched sheet bundle and a lower sheet ejection tray 83 for accommodating the center-folded sheet bundle.

[Paper Conveying Path of Post-Processing Device C and Upper Mechanism] FIG. 2 is a schematic view showing the paper conveying route of the post-processing device C, and FIG. 3 is a sectional view showing the upper mechanism of the post-processing device C.

The post-processing apparatus C is installed with its position and height adjusted so that the receiving section 11 for the sheets S carried out from the image forming apparatus main body A coincides with the paper discharge section 7C of the image forming apparatus main body A. .

The conveying path for the sheet S connected downstream of the pair of inlet rollers 12 of the receiving section 11 in the sheet conveying direction has three systems: a first conveying path in the upper stage, a second conveying path in the middle stage, and a third conveying path in the lower stage. The sheet S is fed to one of the transport paths by selecting the angle occupied by the switching means G1 and G2.

(Discharge to the upper discharge table 81) The image-formed sheet S discharged from the image forming apparatus main body A is introduced into the receiving section 11, is conveyed by the pair of entrance rollers 12, and passes through the entrance. Entrance sensor PS for detection
1, the length of the sheet S in the transport direction is detected. The sheet S passes through the passage 13 on the right side of the upper first switching unit G1, is sandwiched and conveyed by the drive roller 14A and the driven roller 14B of the upper conveying roller pair 14, and further the conveying roller pair 1
After being nipped and conveyed by the sheet 5, the sheet is nipped by the pair of ejection rollers 16 and ejected onto the upper sheet ejection tray 81 on the upper outside of the machine, and sequentially stacked (first conveyance path).

In this paper conveyance process, the switching means G1
Is swung by the drive of the solenoid SD1 to close the passage 17 and open the passage 13 so that the sheet S can pass through the upper sheet discharge tray 81.

A maximum of about 200 sheets of paper S can be accommodated in the upper paper ejection tray 81, and the operator can easily take out the paper from the upper portion of the post-processing apparatus C.

(Shift processing or non-sorting) When this conveying mode is set, the switching means G1 closes the passage 13 and keeps the passage 17 open while the solenoid SD1 is off, and the passage of the sheet S Allows 17 passages.

The image-formed sheet S discharged from the main body A of the image forming apparatus passes through the receiving portion 11 and the pair of inlet rollers 12, and passes through the passage 17 formed below the switching means G1 in an open state. Then, it is sandwiched by the pair of transport rollers 18, passes through the passage 21 above the second switching means G2 that is the second transport path, which is obliquely below, is sandwiched by the pair of transport rollers 22, and is transported through the passage 23. The upper roller 26A and the lower roller 26 are sandwiched by a roller pair (shift roller pair) 24.
The sheet is discharged and placed on the up-and-down sheet discharge tray 82 outside the machine by the discharge roller pair 26 including B (second transport path). Reference numeral 27 is a swinging means for swinging the upper roller 26A against the lower roller 26B so that they can be pressed into contact with and separated from each other.

A maximum of about 3000 sheets of paper S can be accommodated in this elevating and discharging tray 82.

[End-Binding Processing] The image-formed paper S that has been subjected to image forming processing in the image forming apparatus main body A and has been sent to the receiving section 11 of the post-processing apparatus C has an inlet roller pair 12,
Passing through the passage 17 below the first switching means G1,
It is nipped by the pair of transport rollers 18 and is transported to the third transport path.

In the third conveying path, the sheet passes through the passage 31A below the sheet means G2 having a size larger than A4 and B5, and is nipped and conveyed by the downstream conveying roller pair 32. The sheet S is sandwiched by a conveying roller pair 34 composed of a driving roller 34A and a driven roller 34B located further downstream, is sent out, and is discharged to a space above the intermediate mounting table 35 which is inclined, and the intermediate mounting table 35 or the intermediate mounting table 35. After contacting the upper surface of the sheets S stacked on the table 35 and slidingly rising, the trailing end portion of the sheets S in the traveling direction is discharged from the conveying roller pair 34, and then the sheets S are lowered due to their own weight to the middle. The sheet slides down on the inclined surface of the mounting table 35, and the leading end of the sheet S in the traveling direction abuts on the sheet abutting surface of the edge binding abutting member 41 in the vicinity of the stapling means 40 and stops.

In the third conveying path, small size sheets S of A4 size, B5 size, etc. are efficiently and continuously conveyed to improve copy productivity, so that the passage 31A below the switching means G1 is provided. A parallel passage 31B and a switching means G3 are provided.

Solenoid SD2 for switching means G2,
When the solenoid SD3 for the switching means G3 is driven together, the tip ends of the switching means G2 and G3 both swing in the counterclockwise direction shown in the figure, closing the passages 21 and 31A and opening the passage 31B.

The leading end portion of the first sheet S sent out from the conveying roller pair 18 passes through the passage 31B, comes into contact with the peripheral surface of the conveying roller pair 34 in the rotation stopped state, and stops.

Next, the energization of the solenoid SD3 is turned off, the tip end of the switching means G3 swings clockwise, closing the passage 31B and opening the passage 31A. The leading end portion of the second sheet S sent from the transport roller pair 18 passes through the passage 31A and the rotation of the transport roller pair 34 is stopped.
It comes into contact with the peripheral surface of and stops.

The conveying roller pair 34 is driven and rotated at a predetermined timing, and the two sheets S are nipped and conveyed at the same time, and are discharged onto the intermediate mounting table 35. The third and subsequent sheets are discharged one by one.

Reference numeral 36 is an upstream side width aligning means composed of a pair of width aligning members provided on both side surfaces of the intermediate mounting table 35. At least one width aligning member of the upstream side width aligning means 36 is movable in a direction orthogonal to the sheet transport direction, and is opened wider than the sheet width when the sheet S is received on the intermediate loading table 35, When sliding down on the intermediate mounting table 35 and contacting the end binding abutting member 41 and stopping,
The side edge of the sheet S in the width direction is tapped to align the width of the sheet bundle (width alignment). At this stop position, when a predetermined number of sheets S are stacked and aligned on the intermediate mounting table 35, the stapling means 40 performs a binding process to bind the sheet bundle.

A notch is formed in a part of the sheet stacking surface of the intermediate mounting table 35, and a plurality of discharge belts 38 wound around a drive pulley 37A and a driven pulley 37B are rotatably driven. . A part of the discharge belt 38 is provided with the discharge claw 3
8a is integrally formed, and its tip draws an elliptical locus as shown by the dashed line in the figure. The stapled sheet bundle is held on the discharge belt 38 by holding the rear end of the sheet S by the discharge claws 38a of the discharge belt 38, slides on the mounting surface of the intermediate mounting table 35, and obliquely moves upward. The discharge roller pair 26 is pushed up to the pressure contact nip position. The sheet bundle sandwiched by the pair of rotating discharge rollers 26 is discharged and stacked on the elevating paper discharge tray 82.

[Cover Sheet Feeding] The cover sheet feeding section 50 is provided with the sheet feeding tray 5.
1, a movable bottom plate 52, a cover lever 53, and a cover sheet placing section, and a cover sheet feeding unit including a feed roller 54, a paper feed roller 55, a separation roller 56, and the like.

One cover sheet K fed from the cover sheet feeding section 50 passes through the passage 57, passes through the position where the driving roller 14A and the driven roller 14C of the conveying roller pair 14 are held,
After passing through the passage 19 and the conveying roller pair 18, the sheet reaches the intermediate mounting table 35 via the conveying roller pair 32, the passage 33, and the conveying roller pair 34 of the third passage.

The conveying roller pair 14 is the drive roller 1 at the center.
4A and two driven rollers 14B and 14C that are in pressure contact with the drive roller 14A. When the drive roller 14A is driven to rotate to the left in the figure, the driven roller 14B rotates to the right and conveys the sheet S conveyed from the path 13 upward. At the same time, the driven roller 14C also rotates to the right to convey the cover sheet K conveyed from the passage 57 to the passage 19 below. Therefore, by the drive rotation of the drive roller 14A, the first
It is possible to simultaneously transport the paper S on the transport path and the cover sheet K on the fourth transport path in opposite directions.

[Saddle Stitching Processing] FIG. 4 is a sectional view showing the stapling processing section and the center folding processing section of the post-processing apparatus C.

The stapling means 40 has a two-part structure of an upper mechanism 40A and a lower mechanism 40B, and a passage 42 through which the paper S can pass is formed in the middle thereof.

Two sets of the stapling means 40 are arranged in a direction orthogonal to the sheet conveying direction, and can be moved in a direction orthogonal to the sheet conveying direction by a driving means (not shown). By this stapling means 40, staples SP are struck at two centrally distributed locations in the paper width direction (see FIG. 6A).

When the saddle stitching mode is set, the end stapling abutment member 41 near the stapling position of the stapling means 40 retracts from the fifth conveyance path, and at the same time, the saddle stitching abutment member 43 downstream thereof. Is activated and the passage 42
Is shut off (see FIG. 2).

When the size (length in the carrying direction) of the cover sheet K and the sheet S is set or detected, the saddle-stitching abutting member 43 moves to a predetermined position and stops.

After the cover sheet K is placed at a predetermined position on the intermediate placing table 35, the sheet S carried out from the image forming apparatus main body A is conveyed.
From the entrance conveyance section 10 of the post-processing apparatus C through the third conveyance path, and are sequentially stacked on the upper surface of the cover sheet K placed on the intermediate placing table 35, and the end portion of the sheet S is projected for saddle stitching. The abutting member 43 is contacted and positioned. Paper S during saddle stitching
Similarly to the upstream side width alignment means 36, the downstream side width alignment means 46 composed of a pair of width alignment members that regulates the width direction of the sheet S moves the side edge of the paper S in the width direction. Align the width by tapping.

The upstream side width aligning means 36 and the downstream side width aligning means 46 selectively perform the width aligning drive according to the setting of the edge stitching process or the saddle stitching process. That is, only the upstream side width matching means 36 is driven during the edge binding process, and the downstream side width matching means 4 is driven.
6 does not drive. At the time of saddle stitching, the upstream side width matching means 3
6 and the downstream side width matching means 46 are driven. During this saddle stitching process, the downstream side width matching means 46 is driven later than the upstream side width matching means 36.

During the saddle stitching process, the upstream side width aligning means 36 first aligns the width of the sheet S conveyed on the intermediate mounting table 35 and advancing upstream of the stapling means 40. Next, the sheet S that passes through the stapling means 40 and advances toward the saddle-stitching abutting member 43.
On the other hand, the downstream side width aligning means 46 performs width alignment to align the sheets. In this way, the sheets S and the cover sheet K which are advanced on the intermediate mounting table 35 and are extended and stacked centering around the stapling means 40 over the upstream side and the downstream side are stacked with the upstream side width aligning means 36 and the downstream side. With the side width matching means 46, the width of the sheet S is accurately aligned over the entire length.

After the final sheet S is positioned and placed on the intermediate placing table 35, the stapling means 40 performs a saddle stitching process on the sheet bundle including the cover sheet K and all the pages of the sheet S. By this saddle-stitching processing, the staples SP are driven in the central portions of the cover sheet K and the sheet S in the transport direction. Staples S
P is a lower mechanism 40 having a staple needle driving side.
From B, an upper mechanism 40 having a staple bending side
Driven toward A.

[Center Folding Process] After the saddle stitching process, the saddle stitching abutting member 43 swings to open the passage downstream of the passage 42. The saddle-stitched cover sheet K and the sheet bundle of sheets S pass through a curved path and a pair of intermediate conveying rollers 61 and are conveyed by being guided by a guide plate 63 on a conveying belt 62 obliquely below the first sheet. 2 The sheet is conveyed on the sheet stacking unit (stack table) 64, and the leading end of the sheet bundle in the conveying direction is brought into contact with a predetermined position by contacting the folding unit abutting member 650 which is a positioning member of the folding unit movable abutting unit 65. It stops (6th conveyance path shown in FIG. 2). The folding portion abutting member 650 can be moved to a predetermined position by setting or detecting the paper size and driving means.

A sheet ejecting means 66 is installed at a central portion of the stopped sheet bundle in the conveying direction, that is, diagonally below the saddle stitching position. A center-folding portion 67 and a pressing portion 68 are installed diagonally above the saddle-stitching position.

The center-folding processing section 60 has a sheet ejecting means 6
6, a center-fold forming portion 67, a pressing portion 68, and the like.

In response to the center-folding start signal, a center-folding plate member (hereinafter referred to as center-folding knife) 661, which is a movable protrusion plate of the sheet protrusion means 66, advances diagonally straight upward, and the tip portion of the center-folding knife 661 becomes The central portion of the sheet bundle including the cover sheet K and the sheet S is pushed up, and the sandwiching portion of the center-folding roller pair 671 that is driven to rotate through the sheet bundle is spread to swing and separate.

After the front end of the center folding knife 661 has passed through the holding section, the center folding knife 661 retracts, and the center section of the sheet bundle is pinched by the center folding unit 67 to form a fold line. . This fold line substantially coincides with the driving position of the staple needle SP on the sheet bundle by the saddle stitching process described above.

A pair of rotating center folding rollers 671A and 671B of the center folding unit 67 (hereinafter referred to as center folding roller pair 67).
The central portion of the sheet bundle, which is pressed by (1) to form a fold line, is sent to the pressing unit 68 and holds a pair of pressing rollers 681A and 681B (hereinafter, referred to as a pressing roller pair 681). The crease is pressed more strongly at the position.

The fed sheet bundle is nipped by the pressure unit 68 and conveyed, and is ejected onto the lower sheet ejection tray 83 outside the machine (seventh conveyance path shown in FIG. 2).

FIG. 5 is a schematic diagram showing the conveyance path of the cover sheet K and the sheet S, and the saddle-stitching and center-folding process of the sheet bundle, FIG. 6 (a).
Is a plan view of the sheet that has been saddle-stitched by stapling the staples SP at two locations along the fold portion a for folding the sheet S in the center, and FIG. 6B shows post-processing of the saddle stitching and the center-folding. FIG. 6 (c) is a perspective view showing the post-processed sheet bundle in a spread state.

The cover sheet K is placed on the sheet feeding tray 51 of the cover sheet feeding section 50 with the first surface (first page p1 and eighth page p8) facing upward. The cover sheet K fed from the sheet feeding tray 51 by the sheet feeding means is conveyed through the fourth conveying path and the third conveying path, and is conveyed on the intermediate mounting table 35 to the first surface (p1, p).
8) is placed on the lower side.

Next, the image-formed sheet S carried out from the image forming apparatus main body A is introduced into the post-processing apparatus C with the first surface (the third page p3 and the sixth page p6) facing down. It The sheet S is conveyed from the entrance conveying section 10 to the third conveying path, and the first sheet is placed on the cover sheet K placed on the intermediate placing table 35.
It is placed face down.

On the intermediate mounting table 35, the cover sheet K and the sheet are aligned, and the staple means SP is driven by the staple means 40 to perform the saddle stitching process.

The saddle-stitched sheet bundle passes through the fifth transport path, is placed at a predetermined position on the second sheet stacking section 64 and the transport belt 62, and is stopped. At this time, in the sheet bundle, the sheet S has the first surface (p3, p6) on the upper side and the cover sheet K on it.
Is placed with the first surface (p1, p8) facing upward.

Next, a center folding process is performed by the pushing-up operation of the sheet ejecting means 66 and the rotation of the center folding roller pair 671. Subsequently, the sheet is sandwiched and conveyed by the pressure unit 68, and the lower sheet discharge outside the machine. It is discharged onto the table 83.

The sheet bundle (booklet) produced by the saddle stitching process and the center folding process has the first surface (p1, p8) of the cover sheet K facing outward, and the second surface (p2, p7) on the back side thereof. Further, the first surface (p3, p6) of the paper S, which is the content, is arranged inside thereof, and the second surface (p4, p5) of the paper S is arranged inside thereof, and as shown in the figure, it is composed of pages 8 (p1 to p8). The pages of the booklet can be arranged.

When the booklet creation auto mode is selected and set on the operation section of the image forming apparatus main body A, the cover sheet K is stacked on the paper feed tray 51, and printing is started, the control section of the image forming apparatus main body A The image process described above is performed,
The sheet S carrying the image is subjected to saddle stitching processing and center folding processing by the post-processing device C to continuously produce booklets,
Is discharged.

In the operation unit of the post-processing apparatus C, the booklet making manual mode is selected and set, and the cover sheet K and one image-formed sheet S below it are stacked on the sheet feeding tray 51. When the feeding operation is started, the control unit 90 of the post-processing apparatus C (see FIG. 17, which will be described later) performs saddle-stitching processing and center-folding processing on the cover sheet K and the sheet S, and one booklet is produced. Created and discharged.

FIG. 7 is a cross-sectional view of the center folding processing section 60 including the folding section movable butting means 65, the sheet ejecting means 66, the center folding forming section 67, and the pressing section 68. FIG. 8 is a perspective view of the center folding processing unit 60.

The folding portion movable butting means 65 abuts on the leading end portion of the sheet bundle of various sizes conveyed on the second sheet stacking portion 64 and positions the leading end portion. The folding portion butting member 650 is fixed to the holding member 651. The holding member 651 is driven by the motor M1 and the rod-shaped guide member 6
It is slid to 52 and moved linearly. Actuator 653
The folding sensor PS2 detects the passage of the leading edge of the sheet S conveyed on the second sheet stacking unit 64.

The control means 90 causes the drive means to reciprocally move the folding portion abutting member 650 in the conveying direction of the sheet bundle at the timing when the leading end of the sheet bundle in the conveying direction abuts on the folding portion abutting member 650. The leading edge of the sheet S is surely aligned.

After the leading edge of the sheet S is aligned, the movable holding member 662 moves straight along the rod-shaped guide member 663 which is fixedly arranged by the center folding start signal, and the center folding knife 661 fixed to the movable holding member 662 is moved. , Projects upward from the sheet stacking surface. The center folding knife 661 has a knife shape made of a thin plate such as a stainless steel plate, and its tip has an acute angle. The tip of the center folding knife 661 is formed on a low-friction surface, and is subjected to, for example, gloss finish or surface treatment such as fluororesin coating.

One of the pressing means of the center-folding formation 67 supports the center-folding roller 671A, which is connected to a drive source and is driven, and the center-folding roller 671A so as to be rotatable.
A supporting member 672A which is a supporting member swingable around A
And a spring 674A which is locked to one end of the support member 672A and biases the center folding roller 671A toward the holding position.

The other pressing means of the center-folding portion 67 has the same structure, and includes the center-folding roller 671B and the supporting member 672.
B, a support shaft 673B, and a spring 674B.

A pressure unit 68 is arranged downstream of the center-folding unit 67 in the sheet conveying direction. The pressure unit 68 is composed of a pressure roller pair 681 that is driven by being connected to a drive source.

The pair of pressure rollers 681A and 681B have a rubber coating layer. For example, the rubber coating layer is ethylene-
It is formed from an elastic material such as propylene rubber (EPDM).

When the pressure roller pair 681 is a pair of metal rollers, when the rear end of the sheet bundle passes through the pressure contact position of the pressure roller pair 681, a hitting sound is generated due to the collision between the metal rollers. It should be noted that it is effective that one of the pressure roller pair 681 is a hard roller made of metal or the like in order to maintain uniform pressing force during the folding process.

The sheet bundle, which is pinched by the pair of rotating center folding rollers 671 to form the fold line a, is sent to the holding position of the pressure roller pair 681, and at this position, the fold line a is formed.
Is further pressurized and is discharged to the lower discharge tray 83 outside the machine.

(Center Folding Roller Driving Mechanism) FIG. 9 shows a center folding roller driving means for driving the center folding roller pair 671, the pressure roller pair 681, and the conveyor belt 62 shown in FIG. FIG. 9 is a configuration diagram of (second driving means) 670.

The motor M2 includes a timing belt (hereinafter,
A two-stage pulley P1 rotatably supported by an intermediate shaft via a belt (also called a belt) B1 is rotated. A belt B2 is stretched around the pulley P1 to rotate the pulley P2. The pulley P2 rotates the drive roller 611 of the intermediate conveyance roller pair 61 via the belt B3.

The belt B2 that winds around the pulley P2 winds the pulleys P3 and P4 of the intermediate shaft and the pulley P5 fixed to the shaft end of the pressure roller 681B to rotate them simultaneously.
P6 and P7 are tension pulleys.

The drive roller 621 fixed on the rotary shaft of the pulley P2 rotates the conveyor belt 62 stretched between the drive roller 621 and the driven roller 622.

The intermediate shaft pulley P3 rotates the pulley P8 fixed to the shaft end of the center folding roller 671A via the belt B4. The intermediate shaft pulley P4 rotates a pulley P9 fixed to the shaft end of the center folding roller 671B via a belt B5.

A pulley P8 at the shaft end of the center folding roller 671A
Has a built-in one-way rotation clutch CA. A one-way rotation clutch CB is built in the pulley P9 at the shaft end of the center folding roller 671B.

The gear g1 fixed to the shaft end of the pressure roller 681B is connected to the gear g4 via gears g2 and g3 rotatably supported at a fixed position on the panel of the apparatus body.

The gear g3 is rotatably supported by a support shaft 689 which is planted in a panel of the apparatus body. Gear g4
Is fixed to the shaft end of the pressure roller 681A supported by the swing plate 687.

The two swing plates 687 are swingably supported by both shaft ends of a support shaft 689 to which the gear g3 is fixed.
It is biased by a spring 688. Both shaft ends of the pressure roller 681A to which the gear g4 is fixed are rotatably supported by the swing plate 687.

Pressure roller 68 supported by rocking plate 687
1A swings around a support shaft 689, is urged by a spring 688, and comes into pressure contact with a pressure roller 681B.

(Mechanism for Driving Center Folding Plate Member) FIG. 10 is a plan view of center folding knife drive means (first drive means) 660 for moving the center folding knife 661. Since the sheet ejecting means 66 is line-symmetric with respect to the illustrated center line CL, part of the drawing is omitted. Figure 11
FIG. 6 is a cross-sectional view of a center-folding knife drive means (first drive means) 660. 10 and 11 each show the state immediately before the center-folding processing of the sheet bundle.

The motor M3 rotates a large diameter gear g8 via gears g5, g6 and g7. The gear g8 is rotatably supported by a support shaft 665 which is planted on a fixed substrate 667. An eccentric cylindrical member 664 is integrally formed on the bottom of the gear g8. The ring-shaped recess 664A formed in the eccentric cylindrical member 664 is rotated by the gear g8 so that the support shaft 665 is rotated.
Eccentric shaft 664B different from the rotation center of
Make an eccentric movement.

A roller 666 planted in the movable holding member 662 is movably transferred to the inner wall of the annular recess 664A. 666A is a movement locus of the center of the roller 666.

The movable holding member 662 is supported so as to be linearly reciprocable along two guide bars 663 arranged in parallel with the fixed substrate 667. By the rotation of the gear g8,
The annular recess 664A moves eccentrically, the roller 666 moves along the inner wall of the annular recess 664A, and the movable holding member 662 moves.
Moves linearly along the two guide members 663. The center folding knife 661 fixed to the movable holding member 662 also moves straight forward and backward at the same time.

(Center-Folding Process of Paper) In FIG. 12, the fold line a of the sheet bundle Sa has a center-folding roller pair 6
FIG. 7 is a cross-sectional view showing a state of passing through 71.

When the motor M3 starts driving, the center folding knife 661 held by the movable holding member 662 moves forward.
The tip portion of the center folding knife 661 projects a fold line “a” at the center of the sheet bundle Sa in the sheet conveying direction, and feeds it to the pressure contact position of the center folding roller pair 671 that is not rotating, and performs center folding of the sheet bundle Sa. , Forming a center-folded portion.

The tip portion of the center folding knife 661 has the sheet bundle S
The folding part of a is projected, and the center folding roller pair 671
When the sheet is slidably brought into contact with the outer peripheral surface of the sheet and is sent to the pressure contact position, the center folding roller pair 671 is rotated together with the moving sheet bundle Sa by the one-way rotating clutches CA and CB provided at the respective shaft ends of the center folding roller pair 671. Then, it is driven to rotate only in the sheet conveying direction.

The tip portion of the center folding knife 661 advances to the maximum pushing position Y slightly (2 to 10 mm) beyond the pressure contact position X of the center folding roller pair 671 and pushes the sheet bundle Sa into the center folding state. Start the return operation. During the returning operation of the tip portion of the center folding knife 661, after the center folding portion of the sheet bundle Sa has passed the pressure contact position X of the center folding roller pair 671,
The driving of the motor M2 is started, and the driving rotation of the center folding roller pair 671 is started.

The center-folding knife 661 continues the returning operation, and the center-folding knife 6 moves from the folding portion of the sheet bundle Sa.
The leading end of the sheet bundle 61 is pulled out, and the folded portion of the sheet bundle Sa is pressed against and held by the outer peripheral surface of the center folding roller pair 671.
The crease is strongly attached.

When the tip of the center folding knife 661 is pulled out from the folding portion of the sheet bundle Sa, the center folding roller pair 671 is prevented from being reversed by the one-way rotation clutches CA and CB. There is no retreat.

The above is the basic operation of the center folding process. For details of the sheet post-processing apparatus of the present invention for improving folding performance,
This will be described in detail in the first to fourth embodiments described later.

(Paper Pressing Process) FIG. 13 is a cross-sectional view showing a state in which the center-folded sheet bundle Sa passes through the pressing unit 68.

The leading end of the sheet bundle Sa that has passed the pressure contact position of the rotating center folding roller pair 671 is sent to the pressure contact position of the rotating pressure roller pair 681. The front end portion of the sheet bundle Sa rotates at a fixed position, and the pressure roller 68 that rotates and is supported by a swing plate 687 so as to swing.
The fold line is further strengthened by being pressed into contact with 1A.

The support member 672A is swingably supported about the support shaft 673A and is urged by a spring 674A. The swing plate 687 is swingably supported about a support shaft 689 and is biased by a spring 688.

The center-folded sheet bundle Sa, which is nipped by the pair of center-folding rollers 671 and conveyed, is pushed between the pair of pressure rollers 681 whose rollers are widened, and pressed and nipped by the pair of pressure rollers 681. After the folds are firmly attached, the sheet bundle Sa is transported smoothly regardless of the thickness thereof.

(Discharge of Sheets) FIG. 14 is a sectional view showing a state in which the center-folded and pressure-processed sheet bundle Sa is discharged.

The sheet bundle Sa that has passed the nip position of the rotating pressure roller pair 681 is carried out of the apparatus. Sheet bundle S
When the rear end of the a passes through the sandwiching position of the pressure roller pair 681, the center folding roller pair 671 returns to the initial closed state, and the leading ends of the supporting members 672A and 672B abut the elastic stop member 678. Stop.

The center folding roller pair 671 and the pressure roller pair 681 are not limited to each pair, and any number of pairs may be arranged as required.

[Gap Adjusting Mechanism of Center Folding Roller] FIG.
FIG. 9 is a configuration diagram of a center folding roller gap variable drive unit (third drive unit) 69 that varies the sandwiching gap of the center folding roller pair 671 in the sheet bundle standby state. It should be noted that FIG.
The state immediately before the center folding processing of a is shown.

A fan gear g10A is fixed to the end of a support member 672A that rotatably supports the center folding roller 671A. The pitch circle of the sector gear g10A is an arc centered on the support shaft 673A of the center folding roller 671A. The fan gear g10A is rotated by the power transmitted from the drive gear g11 of the motor M4 as the drive source via the intermediate gear g12A and the gear g13A.

Further, at the end of the supporting member 672B that rotatably supports the center folding roller 671B, a sector gear g10 is provided.
B is fixed. The pitch circle of the sector gear g10B is
It is an arc centered on the support shaft 673B of the center folding roller 671B. The fan gear g10B is rotated by power transmitted from the drive gear g11 of the motor M4 that is the drive source via the intermediate gear g12B and the gear g13B.

When the drive gear g11 of the motor M4 is rotated in the counterclockwise direction indicated by the arrow, the intermediate gear g12A and the gear g13.
The fan gear g10A is rotated in the clockwise direction of the arrow via A, the support member 672A is rotated in the clockwise direction about the support shaft 673A, and the support member 672A supporting the center folding roller 67A is centered on the support shaft 673A. And spring 67
It is rotated clockwise against the urging force of 4A and is separated from the holding position.

At the same time, when the drive gear g11 of the motor M4 is rotated in the counterclockwise direction indicated by the arrow, the intermediate gear g12A,
The sector gear g10B is rotated in the counterclockwise direction indicated by the arrow via the gear g13B and the gear g13B, and the support member 672B is rotated by the support shaft 6a.
The support member 672B, which is rotated counterclockwise around the center 73B and supports the center folding roller 671B, is provided with a support shaft 673.
It is rotated counterclockwise around B with respect to the biasing force of the spring 674B, and is separated from the holding position.

Center folding roller 671A and center folding roller 67
When 1B is separated from the sandwiching position, a gap δ is formed.

Sheet bundle S thicker than the set maximum holding gap
When a passes through the nipping gap of the center folding, the motor M4
Drive transmission is cut off by a clutch CC provided on the drive shaft of an intermediate gear g12A driven by
Let 13B rotate freely. The center-folding roller pair 671 is spread by the sheet bundle Sa, presses the sheet bundle Sa through the sheet bundle Sa, and forms a fold line.

FIG. 16 is a front view showing the variable gap control of the center folding roller pair 671. FIG. 17 is a block diagram showing control of the post-processing device.

When a sheet size signal, a sheet number signal, a saddle stitching designation signal, and a center folding designation signal are input to the operation section of the image forming apparatus main body A, the control means 90 executes the saddle stitching and center folding processing. Control.

In the post-processing apparatus C, the entrance sensor P
The passage of the sheet bundle Sa is detected by S1, the folding section sensor PS2, and the sheet discharge section sensor PS3. HP sensor PS4
Detects the initial position of the center folding knife 661.

(1) In FIG. 16A, the number of sheets of the sheet bundle Sa is 2 to 10 (the number of sheets before the center folding processing is 1 to 5).
The initial position of the center folding roller pair 671 in the case of is shown.

[0121] A small number of paper sheets Sa having a sheet number of 5 or less Sa
On the other hand, when the center folding knife 661 is pushed out and pushed into the nipping position between the middle folding roller 671A and the middle folding roller 671B to perform the middle folding process, a gap near the nipping position between the center folding roller 671A and the middle folding roller 671B. Δ = 0
Set to. A small number of sheets Sa of less than 5 sheets Sa
On the other hand, since the sheet bundle Sa has a small resistance and the center folding process can be easily performed, the center folding rollers 671A and 671B are held in the pressure-bonded initial state.

(2) In FIG. 16B, the number of sheets of the sheet bundle Sa is 12 to 20 (the number of sheets before the center folding processing is 6 to 10).
The initial position of the center folding roller pair 671 in the case of (sheets) is shown.

A sheet bundle S having 6 to 10 sheets
When a center folding process is performed for a, the center folding roller 6
71A and the center folding roller 671B are set to a gap δ1 in the vicinity of the sandwiching position. That is, when the number of sheets of 6 sheets or more and 10 sheets or less is set in the operation unit of the image forming apparatus main body A and the sheet number signal is generated, the rotation of the motor M4 is started and the center folding roller in the sheet bundle standby state. The pair 671 is shown in FIG. 16 (b) from the initial position in the sandwiched state shown in FIG. 16 (a).
Transition to the open state shown in. The gap δ1 at the time of opening is smaller than the thickness of the pressed sheet bundle Sa, and δ1 = about 1 mm.
Set to.

(3) In FIG. 16C, the number of sheets Sa is 22 to 32 (the number of sheets before the center folding process is 11 to 1).
The initial position of the center folding roller pair 671 in the case of (6 sheets) is shown.

When the center folding process is performed on the sheet bundle Sa having 11 to 16 sheets, the gap δ2 is set in the vicinity of the sandwiching position between the center folding roller 671A and the center folding roller 671B. That is, when the number of sheets of 11 sheets or more and 16 sheets or less is set in the operation section of the image forming apparatus main body A and the sheet number signal is generated, the center-folding roller pair 671 is driven by the rotation start of the motor M4. 16 (a)
The initial position of the sandwiched state shown in FIG. 16 shifts to the open state shown in FIG. The gap δ2 at the time of opening is smaller than the thickness of the pressed sheet bundle Sa, and δ2 = about 2 mm is set.

When the number of sheets of the sheet bundle Sa is 2 to 32 (the number of sheets before the center folding process is 1 to 16), the gap δ between the center folding roller 671A and the center folding roller 671B is set to 3 as described above. Although the number of stages is set, the present invention is not limited to this, and the number of stages can be appropriately set to three or more.

Further, a stepping motor is used as the motor M4 of the drive source of the center folding roller gap variable drive means (third drive means) 69, and the number of stepping pulses is controlled by the drive circuit to correspond to the number of the sheet bundle Sa. The drive rotation angle may be selected to set the gap δ in multiple stages.

[Another Embodiment of the Gap Adjusting Mechanism of the Center-Folding Roller] FIG. 18 shows the center-fold forming section 67 in the sheet bundle standby state.
It is a block diagram of. FIG. 18 shows a state immediately before the center folding process is performed on the sheet bundle. FIG. 19 is a configuration diagram of the center-fold forming unit 67 showing a state in which a sheet bundle Sa thicker than the set maximum gap passes through the sandwiching gap of center folding. Note that FIG. 18 and FIG.
With respect to the reference numerals used in FIG. 9, the portions having the same functions as those in FIG. 15 are given the same reference numerals. Further, the points different from FIG. 15 will be described.

When the drive gear g11 of the motor M4 is rotated counterclockwise as indicated by the arrow, the gear g13A is rotated counterclockwise.
The gear g13B is rotated in the clockwise direction. The tip end portion of the swinging member 679A fixed on the shaft of the gear g13A is pressed against the abutting portion 672a of the supporting member 672A, and the supporting member 672A is supported about the support shaft 673A to resist the biasing force of the spring 674A. And rotate it in the clockwise direction shown by the arrow. The control unit 90 applies a step number corresponding to the number of sheets to the motor (stepping motor) M4, drives the motor M4, and then stops after a predetermined count. When the motor M4 is stopped, the center folding roller 671A is
It stops at a predetermined position separated from the sandwiching position.

At the same time, the tip of the swinging member 679B fixed on the shaft of the gear g13B is pressed against the abutting portion 672b of the supporting member 672B, so that the supporting member 672B is supported by the supporting shaft 6a.
73B is rotated in the counterclockwise direction of the arrow in the figure against the biasing force of the spring 674B, and stopped at a predetermined position separated from the holding position.

The center folding roller 671A and the center folding roller 67
When 1B is separated from the nipping position, a predetermined gap δ corresponding to the number of sheets is formed.

At the sandwiching position of the center folding roller pair 671, when the sheet bundle Sa thicker than the set maximum gap (see FIG. 16) δ2 is passed, the center folding roller 671 is used.
A and 671B are spread by the sheet bundle Sa pushed into the gap δ2 at the sandwiching position by the forward movement of the center folding knife 661 against the biasing force of the springs 674A and 674B, and pass through the sheet bundle Sa in pressure contact. The fold line a (see FIG. 6).
).

When the center folding roller pair 672 is pushed wider than the maximum gap δ2 by the sheet bundle Sa and the supporting member 672A swings about the support shaft 673A, the abutting portion 672a of the supporting member 672A swings. Moving member 679A
After that, the center folding roller 671A becomes movable. Similarly, the center folding roller 671B is also pushed wider than the maximum gap δ2 by the sheet bundle Sa, the supporting member 672B swings about the support shaft 673B, and the abutting portion 672b of the supporting member 672B swings. The center-folding roller 671B can be moved away from the moving member 679B.

That is, the swinging members 679A and 679B driven by the motor M4 and swinging are the center folding roller pair 67.
By controlling the gap distance from the pressure contact pinching position of 1 (see FIG. 16 (a)) to the maximum gap δ2 (see FIG. 16 (c)),
The sheet bundle Sa is pressed to form a fold portion a (see FIG. 6) and is passed. When passing a sheet bundle Sa thicker than the maximum gap δ2, the central portion of the sheet bundle Sa has the maximum gap δ.
The center folding roller pair 671 is pushed into the holding position set to 2 and the regulation of the swinging members 679A and 679B is released, and is expanded to allow the sheet bundle Sa to pass therethrough to form a fold portion a.

In the embodiment of the present invention, the sheet post-processing apparatus connected to the copying machine is shown. However, the sheet post-processing apparatus used by connecting to an image forming apparatus such as a printer or a facsimile or a light printing machine is used. It is also applicable to.

[0136]

As described above, the following excellent effects can be obtained by the sheet post-processing apparatus of the present invention.

(1) When a thick sheet bundle is pushed into the sandwiching position of the center folding roller pair by the center folding knife, the center portion of the sheet bundle has a predetermined sandwiching position of the center folding roller pair. It is easy to enter and is folded in half. Further, the central portion of the sheet bundle is prevented from being scratched and damaged in the vicinity of the nipping position entrance of the center folding roller pair.

(2) When a thick sheet bundle is pushed into the nipping position of the center folding roller pair by the center folding knife, the driving load of the center folding knife is reduced and the center folding process is smoothly performed.
Further, it is effective for preventing the step-out of the drive source and simplifying the drive source and the drive means.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an image forming system including an image forming apparatus main body, an image reading apparatus, and a sheet post-processing apparatus.

FIG. 2 is a schematic diagram showing a sheet conveyance path of a post-processing device.

FIG. 3 is a sectional view showing an upper mechanism of the post-processing device.

FIG. 4 is a cross-sectional view showing a staple processing unit and a center folding processing unit of the post-processing device.

FIG. 5 is a schematic diagram illustrating a conveyance path of a cover sheet and a sheet, and a saddle-stitching and center-folding process of a sheet bundle.

6A and 6B are a plan view of a sheet subjected to saddle stitching processing, a perspective view of a sheet bundle subjected to post processing of saddle stitching and center folding, and a perspective view of a sheet bundle subjected to post processing in a spread state.

FIG. 7 is a cross-sectional view of a center folding processing unit.

FIG. 8 is a perspective view of a pair of center folding rollers and a center folding plate member.

FIG. 9 is a configuration diagram of a center folding roller driving unit.

FIG. 10 is a plan view of the center-folded plate member driving means (first driving means).

FIG. 11 is a cross-sectional view of a center-folded plate member driving means (first driving means).

FIG. 12 is a cross-sectional view showing a state in which a fold portion of a sheet passes through a center folding roller pair.

FIG. 13 is a cross-sectional view showing a state in which the center-folded sheet passes through the pressure unit.

FIG. 14 is a cross-sectional view showing a state in which a sheet that has undergone center folding and pressure processing is discharged.

FIG. 15 is a configuration diagram of a center folding roller gap variable drive unit.

FIG. 16 is a front view showing a variable gap control of the center folding roller pair.

FIG. 17 is a block diagram showing control of a post-processing device.

FIG. 18 is a configuration diagram of a center-fold forming unit in a sheet bundle standby state.

FIG. 19 is a configuration diagram of a center-fold forming unit showing a state in which a sheet bundle thicker than a set maximum gap passes through a nipping gap for center folding.

[Explanation of symbols]

30 binding processing unit 40 Staple means (binding means) 60 Half-fold processing section 66 paper ejection means 660 Half-fold knife driving means (first driving means) 661 Center folding plate member (center folding knife) 67 Half-fold 670 Center-folding roller driving means (second driving means) 671 Half-folding roller pair 671A, 671B Half-folding roller 672A, 672B support member 679A, 679B swinging member 68 Pressure unit 681 Pressure roller pair 681A, 681B pressure roller 69 Center folding roller gap variable drive means (third drive means) 90 control means A Image forming apparatus body C Paper post-processing device (post-processing device) Sa paper bundle δ, δ1, δ2 gap

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H072 CA01 GA01 GA08 JA02                 3F108 AA01 AB01 AC02 AC03 BA03                       BA08 BB15 CC05 GA02 GA03                       GA04 GB03

Claims (6)

[Claims] 1. A sheet bundle conveyed on a sheet stacking portion is pushed into a nipping position of at least one pair of center folding rollers while pressing a center portion of the sheet bundle in the transport direction by a center folding plate member of a sheet ejecting means, A sheet post-processing device for center-folding a bundle, wherein a sandwiching gap of the pair of center-folding rollers during standby is variably set according to the number of the sheet bundle. 2. A support member for supporting the rollers of the center-folding roller pair is swung by a driving unit, and the gap between the sandwiching portions of the center-folding roller pair is variably set according to the number of sheets of the sheet bundle. The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus is a sheet post-processing apparatus. 3. A sheet bundle conveyed on a sheet stacking section is pushed into the nipping position of at least one pair of center folding rollers while pressing the center section in the direction of conveyance by the center folding plate member of the sheet ejecting means, In a sheet post-processing device for center-folding a bundle, when the center portion of the sheet bundle in the transport direction is pushed into the holding position of the center-folding roller pair by the center-folding plate member, the center-folding roller pair is configured to Following the conveyance of the bundle, it is driven to rotate, and after the center-folding plate member is pulled out from the sandwiching position of the center-folding roller pair, the rotation drive is started after a predetermined time corresponding to the number of the sheet bundle, A sheet post-processing device that discharges a sheet bundle. 4. A central portion of a bundle of sheets conveyed on a sheet stacking portion in the conveying direction is pressed by a center folding plate member of a sheet ejecting means into a holding position of at least one pair of center folding rollers, and the sheets are stacked. In a sheet post-processing apparatus for center-folding a bundle, a first drive unit that moves the center-folding plate member forward and backward, a second drive unit that rotates the center-folding roller pair, and a center-folding roller pair are supported. Third driving means for swinging the supporting member to change the sandwiching gap of the pair of center folding rollers, the first driving means, the second driving means, and the third driving means.
A control means for controlling the drive of the drive means, wherein the control means variably sets the holding gap of the center folding roller pair during standby in accordance with the number of sheets of the sheet bundle. Paper post-processing device. 5. A central portion of a sheet bundle conveyed on a sheet stacking portion in a conveying direction is pressed by a center folding plate member of a sheet ejecting means into a holding position of at least one pair of center folding rollers, and the sheet In a sheet post-processing apparatus for center-folding a bundle, a first drive unit that moves the center-folding plate member forward and backward, a second drive unit that rotates the center-folding roller pair, and a center-folding roller pair are supported. A control means for controlling the drive of the third drive means, the third drive means for swinging the support member, and the swingable swingable member driven by the third drive means. The contact gap of the center folding roller pair is variably set according to the number of sheets of the sheet bundle by pressing the center folding roller pair in the standby state, and a sheet bundle thicker than the set maximum sandwiching gap is used for the center folding. Clamping gap of roller pair When passing the sheet, while the swinging member is stopped at the maximum holding gap, the abutting portion is separated from the pressure contact position, and the center folding roller pair is spread by the sheet bundle to swing. A paper post-processing device characterized by: 6. The stepping motor is used as the drive source, and the control means variably sets the number of steps applied to the stepping motor according to a control signal corresponding to the thickness of the sheet bundle, and the swinging member. 6. The sheet post-processing apparatus according to claim 5, wherein the nipping gap of the center folding roller pair during standby is variably set by swinging.