JP7102942B2 - Sheet folding device and sheet post-processing device equipped with it - Google Patents

Description

The present invention relates to a sheet folding device that folds a sheet of paper or the like image-formed by an image forming device such as a copying machine or a printer, and a sheet post-processing device including the same.

Conventionally, a sheet post-processing device including a sheet folding device that folds a sheet on which an image is formed by an image forming device such as a copying machine or a printer has been used.

As such a sheet folding device, a device including a pair of folding rollers and a folding blade capable of advancing and retreating with respect to the nip portion of the pair of folding rollers is known. In this sheet folding device, the paper is folded by pushing the central portion of the paper into the nip portions of the pair of folding rollers with a folding blade and pressing the paper with the nip portions of the pair of folding rollers.

As the folding roller, a roller having a rubber layer provided on the outer peripheral surface of a metal rotating shaft is usually used. Here, when the outer diameter of the folding roller is made uniform in the axial direction (when the thickness of the rubber layer is uniform), when the pair of folding rollers are pressed against each other, both ends in the axial direction of the folding roller are caused by bending of the folding rollers. The pressure contact force at the portion becomes larger than the pressure contact force at the central portion in the axial direction. Therefore, when the paper passes through the nip portions of the pair of folding rollers, the bending of the paper approaches the central portion from both ends in the axial direction, so that the central portion of the paper is wrinkled.

In order to improve this inconvenience, a sheet folding device including a folding roller whose outer diameter gradually decreases from the central portion in the axial direction toward both ends is known. Each of the pair of folding rollers has a first cylindrical portion arranged in the central portion in the axial direction and a pair having an outer diameter smaller than that of the first cylindrical portion and arranged adjacent to both sides in the axial direction of the first cylindrical portion. It has a second cylindrical portion of the above, and a pair of third cylindrical portions having an outer diameter smaller than that of the second cylindrical portion and arranged adjacent to the outer side in the axial direction of the second cylindrical portion. The tip portion of the folding blade has a pair of convex portions arranged to face the second cylindrical portion and a pair of convex portions arranged to face the third cylindrical portion, and is formed so as to avoid the first cylindrical portion. Has been done.

In this sheet folding device, when a pair of folding rollers are pressed against each other, the pressure contact force at the axial center portion (first cylindrical portion) of the folding rollers becomes the largest. Therefore, when the paper passes through the nip portions of the pair of folding rollers, it is possible to release the bending of the paper from the central portion in the axial direction to the outside to some extent, and it is possible to suppress the occurrence of wrinkles on the paper to some extent. It is possible.

A sheet folding device including a folding roller whose outer diameter gradually decreases from the central portion in the axial direction toward both ends is disclosed in, for example, Patent Document 1.

JP-A-2007-137663

However, in a conventional sheet folding device provided with a folding roller whose outer diameter gradually decreases from the central portion in the axial direction toward both ends, the tip portion of the folding blade is arranged to face the second cylindrical portion. It has a pair of convex portions and a pair of convex portions arranged to face the third cylindrical portion, while being formed so as to avoid the first cylindrical portion. For this reason, the folding blade cannot be uniformly pressed against the paper in the width direction of the paper, and the central portion in the width direction of the paper bends to the upstream side in the pressing direction, so that wrinkles are formed in the central portion in the width direction of the paper. Occurs.

The present invention has been made to solve the above problems, and an object of the present invention is a sheet folding device capable of suppressing wrinkles in a sheet when the sheet is folded. And to provide a sheet aftertreatment device equipped with the same.

In order to achieve the above object, the sheet folding device of the first configuration of the present invention comprises a first roller and a second roller, forms a first nip portion, and allows the sheet to pass through the first nip portion. It includes a first folding roller pair that performs a first folding process for folding the sheet in half, and a folding blade that presses the folding position of the sheet and pushes it into the first nip portion. Each of the first roller and the second roller is formed so that the outer diameter gradually decreases from the central portion in the axial direction toward both ends. Each of the first roller and the second roller is arranged in the central portion in the axial direction, and has a first cylindrical portion having a predetermined outer diameter and an outer diameter smaller than that of the first cylindrical portion of the first cylindrical portion. It has a pair of second cylindrical portions arranged adjacent to each other on both sides in the axial direction. The first cylindrical portion has a large-diameter portion on both sides of the first cylindrical portion in the axial direction and a small-diameter portion arranged at the central portion in the axial direction of the first cylindrical portion and having an outer diameter smaller than that of the large-diameter portion. .. The folding blade has a first convex portion protruding from the tip edge and a pair of second convex portions. The first convex portion is arranged to face the small diameter portion of the first cylindrical portion. The second convex portion is arranged to face the second cylindrical portion.

According to the sheet folding device having the first configuration of the present invention, the folding blade has a first convex portion protruding from the tip edge and a pair of second convex portions, and the first convex portion is a first cylindrical portion. The second convex portion is arranged to face the second cylindrical portion. As a result, the folding blade can be uniformly pressed against the sheet in the width direction of the sheet, so that it is possible to prevent the central portion in the width direction of the sheet from bending upstream in the pressing direction. Therefore, it is possible to suppress the occurrence of wrinkles in the central portion in the width direction of the sheet.

It is a schematic diagram which shows the structure of the image forming system which comprises the paper post-processing apparatus which has the paper folding unit of one Embodiment of this invention, and the image forming apparatus which is connected with the paper post-processing apparatus. It is sectional drawing which shows the structure of the image forming apparatus which connects the paper post-processing apparatus which has the paper folding unit of one Embodiment of this invention. It is sectional drawing which shows the structure of the paper post-processing apparatus which has the paper folding unit of one Embodiment of this invention. It is sectional drawing which shows the structure around the paper folding unit of one Embodiment of this invention. It is a figure which shows the structure around the 1st folding roller pair and the 2nd folding roller pair of the paper folding unit of one Embodiment of this invention. It is a figure which shows the structure around the 1st folding roller pair and the 2nd folding roller pair of the paper folding unit of one Embodiment of this invention, and shows the state which made the bending part in the paper which was subjected to the 1st folding process. It is a figure which shows. It is a figure which shows the structure around the 1st folding roller pair and the 2nd folding roller pair of the paper folding unit of one Embodiment of this invention, and the paper which has been subjected to the 1st folding process is discharged from the lower discharge port. It is a figure which shows the state. It is a figure which shows the structure of the 1st roller and the 2nd roller of the 1st folding roller pair of the paper folding unit of one Embodiment of this invention. It is a figure which shows the structure of the paper folding unit and folding blade of one Embodiment of this invention.

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

With reference to FIGS. 1 to 9, a paper post-processing device (sheet post-processing device) 30 provided with a paper folding unit (sheet folding device) 60 according to an embodiment of the present invention and a paper post-processing device 30 are connected. An image forming system including the image forming apparatus 10 to be formed will be described. In the present embodiment, the multifunction device is illustrated as an example of the image forming apparatus 10, but the paper aftertreatment device 30 of the present invention is other than the digital multifunction device, for example, a laser printer, an inkjet printer, a facsimile device, or the like. It can also be connected to an image forming apparatus.

As shown in FIG. 1, the image forming apparatus 10 is used in connection with the paper aftertreatment apparatus 30. The image forming apparatus 10 is based on the image data input from the outside via a network communication unit (not shown) and the image data read by the image reading unit 11 arranged on the upper part of the image forming apparatus 10. Print the image on the sheet). As shown in FIG. 2, the image forming apparatus 10 includes a paper feeding unit 15 for feeding paper, an image forming unit 18 for forming a toner image on the paper, and a fixing unit for fixing the toner image on the paper. A discharge roller pair 23 and 24, which conveys the fixed paper and discharges the fixed paper to the paper discharge unit 21 and the paper aftertreatment device 30, respectively, and a main body control unit 100 are provided. The main body control unit 100 controls the operation of the image forming device 10 and is configured to be able to communicate with the post-processing control unit 101 of the paper post-processing device 30, which will be described later, and controls the post-processing control unit 101. do.

The paper post-processing device 30 performs post-processing such as punch hole forming processing, binding processing, and folding processing on the paper conveyed from the image forming device 10. The paper post-processing device 30 is not limited to the one that performs post-processing on the paper automatically transported from the image forming apparatus 10, and transports the paper set in the tray (not shown) by the user to a position where the paper can be post-processed by itself. Therefore, the paper may be post-processed.

As shown in FIG. 3, the paper post-processing device 30 includes a punch hole forming device 33 that performs a predetermined punching process on the paper, a staple unit 35 that stacks a plurality of sheets of paper and binds them with staples, and folds the paper into paper. It includes a paper folding unit 60 for performing processing. Further, the paper post-processing device 30 receives the paper carry-in inlet 36 into which the paper discharged from the discharge unit 7 (see FIG. 2) of the image forming apparatus 10 is carried in and the paper discharged from the main discharge port 37. After comprehensively controlling the tray 38, the sub discharge tray 40 that receives the paper discharged from the sub discharge port 39, the evacuation drum 41 that temporarily retracts the paper to a predetermined transport path, and the paper aftertreatment device 30. It includes a processing control unit 101, various switching members, various rollers, and the like.

The paper carry-in port 36 and the main discharge port 37 communicate with each other by the first transport path 42. The second transport path 43, which is branched and connected to the first transport path 42, is connected to the sub discharge port 39. Further, the third transport path 44, which is branched and connected to the first transport path 42, is connected to the paper folding unit 60. Further, the fourth transport path 45 branched and connected to the third transport path 44 curves along the circumference of the evacuation drum 41 and joins the first transport path 42.

The paper carried in from the paper carry-in inlet 36 is sent out to the downstream side by the resist roller pair 46. At the downstream end of the first transport path 42, a main discharge roller pair 47 for feeding paper to the main discharge tray 38 is provided. When the paper is fed to the staple unit 35, the main discharge roller pair 47 is configured to be separated from each other to release the nip. The main discharge tray 38 mainly receives a bundle of paper bound by the staple unit 35. The paper that has not been post-treated or has only been punched may be received by the main discharge tray 38.

At the downstream end of the second transport path 43, a sub-discharge roller pair 48 that feeds the paper to the sub-discharge tray 40 is provided. The sub-discharge tray 40 mainly receives paper that is discharged without post-treatment by the post-treatment device 30 or paper that has been subjected to only perforation processing.

The punch hole forming device 33 is arranged between the paper carry-in inlet 36 and the resist roller pair 46 so as to face upward with respect to the first transport path 42. The punch hole forming device 33 performs a punching process on the paper conveyed through the first conveying path 42 at a predetermined timing.

The staple unit 35 is arranged on the downstream side and below the first transport path 42. The staple unit 35 performs a stacking process of stacking a plurality of sheets to form a paper bundle, and also performs a binding process of binding the stacked paper bundles with staples.

When a plurality of sheets of paper bundles are continuously bound, the save drum 41 saves the first sheet of paper that becomes the next paper bundle when the previous paper bundle is bound. This is for transporting the paper to the staple unit 35 in a state of being overlapped with the second sheet of paper after being temporarily retracted on the outer peripheral surface of the drum 41.

Next, the paper folding unit 60 of the paper aftertreatment device 30 will be described. In the following description, for convenience, "paper S" includes a bundle of a plurality of sheets S in addition to one sheet S.

As shown in FIG. 4, the paper folding unit 60 is provided in the lower part of the paper aftertreatment device 30 and on the downstream side of the third transport path 44. The paper folding unit 60, for example, performs a two-fold or three-fold folding process on the paper S when the folding process is selected by the user.

The paper folding unit 60 includes a paper loading path 61 connected to the downstream end of the third transport path 44, an upstream paper loading section 63a and a downstream paper loading section 63a on which the paper S carried in from the paper loading path 61 is placed. It includes 63b and a matching portion 65 that aligns the positions of the upstream side paper placing portion 63a and the paper S placed on the downstream side paper placing portion 63b.

Further, in the paper folding unit 60, the first folding device 70 that performs the first folding process for folding the paper S in half and the paper S that has been subjected to the first folding process by the first folding device 70 can enter. It includes a standby path 81 and a second folding device 90 that performs a second folding process that folds the paper S that has been first folded by the first folding device 70 in three.

Further, the paper folding unit 60 includes a transport destination switching member 83 that changes the transport destination of the paper S that has been first folded by the first folding device 70, and a lower portion that receives the paper S discharged from the lower discharge port 85. It is provided with a discharge tray 87.

The paper carry-in path 61 is a carry-in path for carrying the paper S transported through the third transport path 44 into the paper folding unit 60. The paper loading path 61 is composed of a loading guide 611 for guiding the paper S, and a loading roller pair 612 for feeding the paper S into the paper folding unit 60 is provided at the downstream end of the loading guide 611.

The upstream side paper placing portion 63a and the downstream side paper placing portion 63b are composed of, for example, plate-shaped members, and are provided diagonally in a straight line from the upper right to the lower left inside the paper folding unit 60. Specifically, the upstream side paper placing portion 63a is arranged on the upstream side in the paper transport direction with respect to the extrusion mechanism 71 described later. On the other hand, the downstream side paper placing portion 63b is arranged on the downstream side in the paper conveying direction with respect to the extrusion mechanism 71, away from the upstream side paper placing portion 63a. A second staple unit 67 that binds the bundle of paper that is folded by the first folding device 70 is arranged above the upstream paper placing portion 63a.

The matching portion 65 includes an upper moving member 651 and a lower moving member 652 that align (match) the front end and the rear end of the paper S placed on the upstream side paper placing portion 63a and the downstream side paper placing portion 63b. , 653a and 653b of width matching members that align (match) the side edges in the paper width direction orthogonal to the paper transport direction of the paper S.

The upper moving member 651 is attached to an upstream belt 655 spanned by an upstream drive pulley 654a and an upstream driven pulley 654b arranged below the upstream paper mounting portion 63a. The lower moving member 652 is attached to a downstream belt 657 spanned by a downstream driving pulley 656a and a downstream driven pulley 656b arranged below the downstream paper loading portion 63b. The lower moving member 652 receives the tip of the paper S. By moving the upper moving member 651 and the lower moving member 652 according to the size of the paper S (the length in the paper conveying direction), the upper moving member 651 and the lower moving member 652 are placed on the upstream side paper placing portion 63a and the downstream side paper placing portion 63b. The position of the paper S is aligned with the paper transport direction (that is, the length direction of the paper S).

A pair of width matching members 653a are provided on the upstream paper placing portion 63a at intervals in the paper width direction (perpendicular to the paper surface in FIG. 4). A pair of width matching members 653b are provided on the downstream side paper placing portion 63b at intervals in the paper width direction. The pair of width matching members 653a are moved according to the size of the paper S (length in the paper width direction) by a rack and pinion mechanism (not shown). Further, the pair of width matching members 653b are moved according to the size of the paper S (length in the paper width direction) by a rack and pinion mechanism (not shown). As a result, the width adjusting members 653a and 653b perform width matching and skew correction of the paper S.

The first folding device 70 includes an extrusion mechanism 71 that extrudes the paper S, and a first folding roller pair 75 that folds the paper S extruded by the extrusion mechanism 71.

The extrusion mechanism 71 is arranged below the first folding roller pair 75 between the upstream side paper placing portion 63a and the downstream side paper placing portion 63b. The extrusion mechanism 71 has a sheet metal folding blade 72 that abuts on the lower surface of the paper S. Further, the extrusion mechanism 71 has a motor and a power transmission mechanism (neither shown) for moving the folding blade 72 perpendicularly to the lower surface of the paper S. The folding blade 72 pushes out the paper S and feeds it into the first nip portion N1 of the first folding roller pair 75, which will be described later.

As shown in FIG. 5, the first folding roller pair 75 is composed of a first roller 76 and a second roller 77 located on the downstream side in the paper transport direction with respect to the first roller 76. The first roller 76 and the second roller 77 are rotationally driven by a motor (neither shown) via a power transmission mechanism.

A first nip portion N1 to which the paper S is fed by the folding blade 72 (see FIG. 4) of the extrusion mechanism 71 is formed between the first roller 76 and the second roller 77. When the paper S is sandwiched between the first nip portions N1 and passes through the paper S, a first crease is formed on the paper S.

A first discharge transport path 88 connected to a lower discharge port 85 (see FIG. 4) is provided on the downstream side of the first nip portion N1 of the first folding roller pair 75. A discharge roller pair 86 is provided at the downstream end of the first discharge transport path 88. The first discharge transport path 88 is a transport path for transporting the first folded paper S to the lower discharge port 85 without performing the second folding process.

The standby path 81 is branched and connected to the first discharge transfer path 88. The transfer destination switching member 83 is provided at a branch portion between the standby path 81 and the first discharge transfer path 88, and by rotating, the transfer destination of the paper S that has been subjected to the first folding process can be changed. 1 Switch between the discharge transport path 88 and the standby path 81.

The waiting path 81 is provided to allow the paper S that has been subjected to the first folding process by the first folding device 70 to enter and bend while being evacuated. The standby path 81 is arranged on the opposite side of the first roller 76 with the transport destination switching member 83 interposed therebetween. The standby path 81 is curved in the direction along the peripheral surface of the second roller 77.

The standby path 81 is formed corresponding to the thickness of the maximum number of sheets S that can be folded by the paper folding unit 60. For example, when the folding process can be performed on 1 to 5 sheets of paper S, the thickness (thickness of 10 sheets) when the 5 sheets of paper S are folded (when the first folding process is performed). The waiting path 81 is configured so that the paper S of)) has a gap that can be entered.

A stopper 81a is provided at the downstream end of the standby path 81. The first crease of the paper S that has entered (evacuated) into the waiting path 81 abuts on the stopper 81a.

The second folding device 90 performs a second folding process on the paper S in a state where the first folding process is performed and the paper S is in contact with the stopper 81a.

Specifically, the second folding device 90 has a second folding roller pair 91 that performs a second folding process on the paper S that has been subjected to the first folding process. The second folding roller pair 91 is composed of the above-mentioned first roller 76 and a third roller 92 located above the first roller 76. The first roller 76 is a common roller used for the first folding roller pair 75 and the second folding roller pair 91. The third roller 92 is rotationally driven by a motor (neither shown) via a power transmission mechanism.

A second nip portion N2 is formed between the first roller 76 and the third roller 92. As shown in FIG. 6, the paper S is bent by the first folding roller pair 75 continuing to convey the paper in a state where the tip of the first folded paper S is in contact with the stopper 81a. A second crease is formed on the paper S by forming S1 and passing the bent portion S1 between the second nip portions N2 of the second folding roller pair 91.

As shown in FIG. 5, a second discharge transport path 89 that joins the first discharge transport path 88 is provided on the downstream side of the second nip portion N2 of the second folding roller pair 91. The second discharge transport path 89 is a transport path for transporting the second folded paper S to the lower discharge port 85 via the first discharge transport path 88.

Next, the folding process (operation) of the paper S by the paper folding unit 60 will be described with reference to FIGS. 4 to 7. The folding process of the paper S is executed by the post-processing control unit 101 (see FIG. 3) included in the paper post-processing device 30.

First, the folding process of folding in half will be described. The folding process is performed when the user selects the folding mode using the operation panel 12 (see FIG. 2) of the image forming apparatus 10. The transport destination switching member 83 rotates to the position shown by the solid line in FIG. 5, and directs the transport destination of the paper S that has been first folded by the first folding device 70 to the first discharge transport path 88. ..

The paper S carried in from the paper loading path 61 is placed on the upstream side paper loading portion 63a and the downstream side paper loading portion 63b, and is aligned by the matching portion 65. Then, the matching portion 65 arranges the paper S at a predetermined position so that the folding position of the paper S (the central portion in the paper transport direction) faces the tip of the folding blade 72. Next, the folding blade 72 of the extrusion mechanism 71 is projected, and the paper S is pushed upward (in a direction perpendicular to the paper S). At this time, the folding blade 72 comes into contact with the folding position of the paper S. The paper S extruded by the folding blade 72 enters the first nip portion N1 of the first folding roller pair 75 in a bent state. A first crease is formed on the paper S that has passed through the first nip portion N1. The paper S in which the first crease is formed is discharged from the lower discharge port 85 to the lower discharge tray 87 through the first discharge transport path 88 (see FIG. 7). The extrusion mechanism 71 returns the folding blade 72 to the original standby position. After that, the folding process is continuously performed in the same manner.

Next, the tri-folding process will be described. The tri-fold process is performed when the tri-fold mode is selected by the user using the operation panel 12 (see FIG. 2) of the image forming apparatus 10. The process until the first folding process is performed on the paper S by the first folding device 70 is described above except that the folding position of the paper S is set to a position of about 1/3 of the paper length from the tip of the paper S. Since it is the same as the folding process of folding in half, the description thereof will be omitted. The transport destination switching member 83 rotates to the position indicated by the alternate long and short dash line in FIG. 5, and directs the transport destination of the paper S that has been first folded by the first folding device 70 to the standby path 81. Therefore, the first folded paper S is conveyed toward the waiting path 81. The paper S enters the standby path 81, and the first crease (tip) of the paper S abuts on the stopper 81a of the standby path 81.

Even after the first crease of the paper S hits the stopper 81a, the first fold roller pair 75 continues to be rotationally driven. Therefore, as shown in FIG. 6, the paper S is projected toward the second nip portion N2 of the second folding roller pair 91 while contacting the inner surface of the curved standby path 81, the transport destination switching member 83, and the like. It bends to.

The bent portion S1 (position of about 1/3 of the paper length from the rear end of the paper S) generated in the paper S enters the second nip portion N2 of the second folding roller pair 91. A second crease is formed on the paper S that has passed through the second nip portion N2. The paper S on which the second crease is formed is conveyed along the second discharge transport path 89 while being wound around the peripheral surface of the third roller 92, and is discharged from the lower discharge port 85 to the lower discharge tray 87 by the discharge roller pair 86. ..

Next, the detailed structure of the first folding roller pair 75 and the folding blade 72 will be described.

As shown in FIG. 8, each of the first roller 76 and the second roller 77 of the first folding roller pair 75 is formed so that the outer diameter gradually decreases from the central portion to both end portions. Specifically, each of the first roller 76 and the second roller 77 is arranged in the central portion in the axial direction, and has a first cylindrical portion 78a having a predetermined outer diameter and an outer diameter smaller than that of the first cylindrical portion 78a. A pair of second cylindrical portions 78b arranged adjacent to each other on both sides of the first cylindrical portion 78a in the axial direction, and having an outer diameter smaller than that of the second cylindrical portion 78b and in the axial direction of the second cylindrical portion 78b. It has a pair of third cylindrical portions 78c arranged adjacent to the outside, and a metal rotating shaft 79 that penetrates and rotatably supports them. The first cylindrical portion 78a, the second cylindrical portion 78b, and the third cylindrical portion 78c are rubber layers provided on the outer peripheral surface of the rotating shaft 79. Since the first roller 76 and the second roller 77 are formed in the same shape, they are shown in one figure in FIGS. 8 and 9.

Here, in the present embodiment, the first cylindrical portion 78a is arranged at the central portion in the axial direction of the first cylindrical portion 78a, and the small-diameter portion R1 formed on the surface so that a concave portion makes one circumference along the circumferential direction. And a pair of large diameter portions R2 arranged adjacent to each other on both sides of the small diameter portion R1 in the axial direction. The small diameter portion R1 has an outer diameter smaller than that of the large diameter portion R2.

As shown in FIG. 9, the tip portion of the folding blade 72 is formed so as to avoid the large diameter portion R2. Further, the folding blade 72 has a first convex portion 72a protruding from the tip edge, a pair of second convex portions 72b, and a pair of third convex portions 72c. The first convex portion 72a is arranged so as to face the small diameter portion R1 without facing the large diameter portion R2. The second convex portion 72b is arranged to face the second cylindrical portion 78b. The third convex portion 72c is arranged to face the third cylindrical portion 78c. The widths of the first convex portion 72a, the second convex portion 72b, and the third convex portion 72c in the axial direction (horizontal direction) are the axial directions (horizontal direction) of the small diameter portion R1, the second cylindrical portion 78b, and the third cylindrical portion 78c, respectively. ) Is formed shorter than the width of). The protrusion amounts of the first convex portion 72a, the second convex portion 72b, and the third convex portion 72c are equal, and the tip positions of the first convex portion 72a, the second convex portion 72b, and the third convex portion 72c are arranged in a straight line. Has been done.

Further, in the present embodiment, the width of each large diameter portion R2 in the axial direction (left-right direction) is A, the width of the small diameter portion R1 in the axial direction is B, and the width of the first convex portion 72a in the axial direction (left-right direction). When the width is C, the relationship of C <A ≦ B is satisfied.

Further, when the outer diameter of each large diameter portion R2 is a, the outer diameter of the small diameter portion R1 is b, and the outer diameter of the second cylindrical portion 78b is c, the relationship of c ≦ b <a is satisfied.

Unlike the first roller 76 and the second roller 77, the third roller 92 is formed to have a constant (uniform) outer diameter in the axial direction.

In the present embodiment, as described above, the folding blade 72 has a first convex portion 72a and a pair of second convex portions 72b, and the first convex portion 72a is arranged to face the small diameter portion R1 and is second. The convex portion 72b is arranged to face the second cylindrical portion 78b. As a result, the folding blade 72 can be uniformly pressed against the paper S in the width direction of the paper, so that the central portion of the paper S in the width direction can be prevented from bending upstream in the pressing direction. Therefore, it is possible to suppress the occurrence of wrinkles in the central portion of the paper S in the width direction. The first convex portion 72a of the folding blade 72 is formed so as not to face the large diameter portion R2. That is, the first convex portion 72a of the folding blade 72 is not nipped into the large diameter portion R2 having the largest pressure contact force. Therefore, when the tip of the folding blade 72 is pulled out from the first nip portion N1 of the first folding roller pair 75, it is possible to suppress an excessive load from being applied to the paper S, so that the paper S is wrinkled. It is possible to prevent the paper S from being damaged.

Further, each of the first roller 76 and the second roller 77 has a first cylindrical portion 78a arranged in the central portion in the axial direction and an outer diameter smaller than that of the first cylindrical portion 78a, and the first cylindrical portion 78a. It has a pair of second cylindrical portions 78b arranged adjacent to each other on both sides in the axial direction. As a result, when the first roller 76 and the second roller 77 are pressed against each other, the pressure contact force at the axial center portion (first cylindrical portion 78a) of the first roller 76 and the second roller 77 becomes the largest. Therefore, when the paper S passes through the first nip portion N1 of the first roller 76 and the second roller 77, the bending of the paper S can be released to the outside from the central portion in the axial direction, so that the paper S is wrinkled. Can be suppressed.

Further, as described above, the axial width of each large diameter portion R2 is A, the axial width of the small diameter portion R1 is B, and the axial width (horizontal direction) of the first convex portion 72a is C. When doing so, the relationship of C <A ≦ B is satisfied. As a result, when the tip of the folding blade 72 is pulled out from the first nip portion N1 of the first folding roller pair 75, it is possible to suppress the load applied to the paper S by the first convex portion 72a, so that the paper S can be suppressed. It is possible to further suppress wrinkles and damage to the paper S.

Further, as described above, when the paper S is subjected to the second folding process, the bent portion S1 of the paper S is first drawn by the large diameter portion R2 of the first roller 76, and is first drawn into the small diameter portion R1 of the paper S. Deflection occurs in the axial direction at the facing portions. At this time, if the width B of the small diameter portion R1 in the axial direction is short, the curvature of the deflection generated in the paper S becomes large, and wrinkles are likely to occur in the paper S when passing through the second folding roller pair 91. Therefore, in the present embodiment, by satisfying the relationship of A ≦ B, it is possible to suppress an increase in the curvature of the deflection generated in the paper S, so that the paper S is formed when it passes through the second folding roller pair 91. It is possible to suppress the occurrence of wrinkles.

Further, as described above, when the paper S is subjected to the second folding process, if the outer diameter b of the small diameter portion R1 is small, the paper S does not come into contact with the surface of the small diameter portion R1. For this reason, the bending that occurs in the portion of the paper S that faces the small diameter portion R1 becomes large, and wrinkles are likely to occur in the paper S when it passes through the second folding roller pair 91. Therefore, in the present embodiment, by satisfying the relationship of c ≦ b <a, it is possible to bring the paper S into contact with the surface of the small diameter portion R1 and prevent the paper S from becoming large in bending. It is possible to further suppress the occurrence of wrinkles on the paper S when passing through the folding roller pair 91.

Further, as described above, each of the first roller 76 and the second roller 77 has an outer diameter smaller than that of the second cylindrical portion 78b and is arranged adjacent to the outer side of the second cylindrical portion 78b in the axial direction. Further has a third cylindrical portion 78c of the above. As a result, when the paper S passes through the first nip portion N1 of the first roller 76 and the second roller 77, the bending of the paper S can be further easily released outward in the axial direction. Further, the folding blade 72 further has a pair of third convex portions 72c protruding from the tip edge and arranged to face the third cylindrical portion 78c. As a result, the folding blade 72 can be pressed evenly against the paper S in the paper width direction.

It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

For example, in the above embodiment, the example in which the paper folding unit 60 includes the first folding device 70 and the second folding device 90 is shown, but the present invention is not limited to this, and the paper folding unit 60 is the second folding device 90. It does not have to be provided.

30 Paper post-processing equipment (sheet post-processing equipment)
60 Paper folding unit (sheet folding device)
72 Folding blade 72a 1st convex part 72b 2nd convex part 72c 3rd convex part 75 1st folding roller vs. 76 1st roller 77 2nd roller 78a 1st cylindrical part 78b 2nd cylindrical part 78c 3rd cylindrical part 81 Standby 81a Stopper 91 2nd folding roller vs. 92 3rd roller N1 1st nip part N2 2nd nip part R1 Small diameter part R2 Large diameter part S Paper (sheet)
S1 Flexible part

Claims (5)

A pair of first folding rollers composed of a first roller and a second roller, forming a first nip portion, and performing a first folding process of folding the sheet in half by passing the sheet through the first nip portion. ,
A folding blade that presses the folding position of the sheet and pushes it into the first nip portion,
With
Each of the first roller and the second roller
It is formed so that the outer diameter gradually decreases from the central part in the axial direction toward both ends.
A pair of second cylinders arranged in the central portion in the axial direction, having a first cylindrical portion and an outer diameter smaller than that of the first cylindrical portion, and arranged adjacent to both sides of the first cylindrical portion in the axial direction. With a part,
The first cylindrical portion has a large diameter portion on both sides of the first cylindrical portion in the axial direction and a small diameter portion which is arranged at the central portion in the axial direction of the first cylindrical portion and has an outer diameter smaller than that of the large diameter portion. And have
When the outer diameter of each of the large diameter portions is a, the outer diameter of the small diameter portion is b, and the outer diameter of the second cylindrical portion is c, the relationship of c ≦ b <a is satisfied.
The folding blade has a first convex portion protruding from the tip edge and a pair of second convex portions.
The first convex portion is arranged so as to face the small diameter portion of the first cylindrical portion.
The sheet folding device, wherein the second convex portion is arranged so as to face the second cylindrical portion. When the axial width of each large diameter portion is A, the axial width of the small diameter portion is B, and the axial width of the first convex portion is C, C <A ≦ B. The sheet folding device according to claim 1, wherein the sheet folding apparatus according to claim 1 is satisfied. Each of the first roller and the second roller has a smaller outer diameter than the second cylindrical portion, and further has a pair of third cylindrical portions arranged adjacent to the axially outer side of the second cylindrical portion. Have and
The sheet folding device according to claim 1 or 2, wherein the folding blade further has a pair of third convex portions that protrude from the tip edge and are arranged to face the third cylindrical portion. A second folding roller composed of the first roller and the third roller, forming a second nip portion, and performing a second folding process of folding the sheet in three by passing the sheet through the second nip portion. Pair and
A waiting path that allows the sheet that has undergone the first folding process to enter and has a stopper that the tip of the sheet comes into contact with.
With more
The bent portion generated in the sheet by continuing the sheet transfer by the first folding roller pair in a state where the tip of the sheet subjected to the first folding process is in contact with the stopper is the second folding. The sheet folding apparatus according to any one of claims 1 to 3, wherein the sheet is subjected to the second folding process by passing through the second nip portion of the roller pair. A sheet post-processing apparatus comprising the sheet folding apparatus according to any one of claims 1 to 4.

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