JP2001010759A - Sheet folder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give accurate folding lines to sheets, ensure folding of the sheets and allow simple binding in desired conditions. SOLUTION: In this device, sheets are fed along a carrying passage and the rear ends of the sheets are cut one by one by a cutter. A single sheet folding part gives folding lines one by one (step S7). When a preset number of sheets are reserved in an alignment part (YES in step S9), staples are driven along the folding lines of the aligned sheets by a binder (step S10) and the bunch of sheets are folded in duplication along the folding lines by a folding part (Step S11).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper folding apparatus which can be combined with an image forming apparatus such as a copying machine or a printer to perform simple bookbinding by collating sheets on which images are formed and output. It is.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 9-183568 discloses a prior art of this type of paper folding apparatus. As described in this publication, a conventional paper folding apparatus combined with an image forming apparatus includes:
In this configuration, a plurality of sheets are collated, and the collated bundle of sheets (laminated paper) is folded. For this reason, when the sheet bundle is thick, it is necessary to reciprocate between the folding roller pairs many times. Further, when the sheet bundle is thick, there is a problem that the crease is not sufficiently formed, the sheet cannot be reliably folded, and the sheet bundle is opened.

[0003] The present invention has been made to solve the above-mentioned problems of the prior art, and it is possible to surely make a fold on a sheet, to reliably fold the sheet, and to easily bind the sheet to a desired state. The main object of the present invention is to provide a paper folding device capable of performing the above-mentioned operations.

[0004]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a transport path for transporting sheets one by one;
Crease applying means for forming a fold in a direction orthogonal to the paper conveyance direction with respect to each paper conveyed along the conveyance path, and a predetermined number of creased papers so that the fold position of each paper is aligned. Means for collating, and means for performing binding processing along the fold of the collated paper, means for folding a predetermined number of sheets subjected to the binding processing along the fold,
And a paper folding device.

[0005] According to the above configuration, the sheets are creased one by one by the crease applying means before being collated. For this reason, a predetermined number of sheets that have been collated can be easily folded along the folds that have been set in advance. Therefore, according to the above configuration, it is possible to provide a paper folding device that can be folded securely and firmly.

According to a second aspect of the present invention, in the paper folding apparatus according to the first aspect, the fold imparting means has a first roller and a second roller arranged along the sheet conveying direction. The first roller and the second roller are arranged such that a line connecting the central axes of both rollers is parallel to the transport path, and the peripheral surfaces of both rollers are in contact with a predetermined pressure. Rotating both rollers so that the central portion of the paper present in the transport path in the transport direction is taken in between the first roller and the second roller, and the paper passes between the first roller and the second roller. As a result, a crease is formed at the center of the sheet, and the first roller and the second roller are rotated in opposite directions to return the sheet to the transport path.

According to the configuration of the present invention, the central portion of the paper is taken in between the first roller and the second roller arranged along the transport direction of the paper, so that the paper in the transport path is reliably creased. Can be. The pressure contact force between the first roller and the second roller only needs to be a pressure necessary and sufficient to fold one sheet of paper. The paper folding device according to claim 3 is the paper folding device according to claim 2, wherein
The roller also serves as a roller for transporting the sheet along the sheet transport path, and the second roller has a diameter of the first roller.
The roller is characterized in that the diameter is smaller than the diameter of the roller so that the roller does not contribute to sheet conveyance.

According to the structure of the present invention, by making the diameter of the second roller smaller than the diameter of the first roller, the second roller rotating in the direction opposite to the rotation direction of the first roller can be used.
The transfer of the sheet by the first roller is not obstructed. Second
The diameter of the roller is preferably smaller than the diameter of the first roller by, for example, a thickness of several sheets.
This is because, when a crease is formed between the first roller and the second roller across the sheet middle part, if the diameter difference between the first roller and the second roller is large, wrinkles and the like are likely to be formed on the taken-in sheet. It is.

According to a fourth aspect of the present invention, there is provided the paper folding apparatus according to the second or third aspect, wherein the folding edge of the sheet taken between the first roller and the second roller and passed between the two rollers is provided. On the other hand, an ironing means for performing an ironing process is further included. According to the configuration of the present invention, the fold can be firmly formed on the sheet, and even when the sheet is returned to the transport path and straightened, the fold does not disappear and it becomes easier to fold after collating.

According to a fifth aspect of the present invention, there is provided the paper folding apparatus according to any one of the first to fourth aspects, further comprising a cutting unit configured to cut an end of the paper conveyed in the conveyance path in a conveyance direction. The cutting means sequentially changes the cutting amount for a plurality of sheets to be collated so that the length of the sheet located inside after folding is shorter than the length of the sheet located outside after folding. The cutting is performed.

If the collated sheets are exactly the same length,
When a plurality of sheets are folded, the ends of the sheets are shorter on the outer side than on the inner side, and are not aligned neatly. Therefore, according to the configuration of the present invention, the paper located inside after folding has a relatively large amount of cut ends, and the paper located outside has relatively few edges cut after being folded. When the sheets are collated and folded, the edges of the plurality of folded sheets are aligned neatly.

According to a sixth aspect of the present invention, in the paper folding apparatus according to any one of the first to fifth aspects, the collating means is configured such that when the collated paper is folded, an end of the paper is inclined. It is characterized in that the edges of the sheets are preliminarily shifted obliquely in the collation so that the collation does not occur. According to the configuration of the present invention, if the ends of the sheets are inclined at the time of collating, the ends of the folded sheets can be aligned neatly when the collated sheets are folded.

In order to align the edges of the folded paper, it is sufficient to cut the edges. In that case, however, the folded sheets must be cut at a stretch, and The device becomes larger. However, if the edges of the sheets are cut one by one as in the configuration of the present invention, the cutting can be performed with a small cutting device, and the size of the entire device does not increase.

[0014]

FIG. 1 is a schematic sectional view showing the configuration of a paper folding apparatus according to an embodiment of the present invention. The paper folding apparatus 1 is connected to, for example, a copying machine 2 to collate a predetermined number of copied sheets discharged from the copying machine 2 and staple the collated predetermined number of sheets.
This is a device that can be folded and easily bound.

In order to perform such processing, the paper folding device 1 includes a transport path 4, a cutter 5 and a pair of registration rollers 6 arranged along the transport path 4, and a fold for a sheet transported through the transport path 4. Single sheet folding portion 7 serving as a fold imparting means, a branch claw 8, a leading end stopper 18 disposed in the transport path 4, a collating portion 9 for collating a predetermined number of creased sheets, and a collating portion 9. Binding device 10 for binding paper
And a folding unit 11 for folding the bound paper
Is provided.

The pair of registration rollers 6 performs so-called skew correction to bend the leading edge of the sheet when the leading edge of the sheet entering the transport path 4 is obliquely distorted, so that the sheet is sent straight. , For adjusting the paper feed timing. The cutter 5 is configured as shown in FIG. 2 and includes a fixed blade 12 and a rotary blade 13.
Is to cut off the trailing end. As it becomes paper 3 later,
Although the cutting amount is large, specific cutting timing and the like will be described later with reference to FIG.

The single sheet folding section 7, the branching claw 8, and the tip stopper 18 are configured as shown in FIG. These configurations will be described with reference to FIG. The single sheet folding section 7 folds the sheet 3 one by one. The single sheet folding section 7 includes a first roller 14 and a second roller 15 whose peripheral surfaces are in contact with a predetermined pressure. The first roller 14 and the second roller 15 are arranged along the direction in which the sheet 3 is conveyed.
And the second roller 15 are arranged such that a line connecting the central axes of the rollers 14 and 15 is parallel to the transport path 4.

The first roller 14 also functions as a transport roller for transporting the sheet 3 along the transport path 4. Specifically, the first roller 14 is provided on the side of the conveyance path 4 of the first roller 14.
A third roller 17 is disposed in contact with the third roller 17.
The paper 3 is nipped by the roller 17 and the first roller 14,
The sheet 3 is transported along the transport path 4. Second roller 1
5 has a diameter smaller than the diameter of the first roller 14 by, for example, a thickness of several sheets. As described above, both rollers 14 and 14 are aligned so that the line connecting the central axes of the first roller 14 and the second roller 15 is parallel to the conveyance path 4.
The second roller 15 does not contribute to the conveyance of the sheet 3. Further, a position sensor 16 is disposed on the side opposite to the side of the transport path 4 when viewed from the first roller 14 and the second roller 15.

The leading end stopper 18 regulates the leading end of the sheet 3 conveyed on the conveying path 4 and is arranged at the end of the conveying path 4 in the conveying direction. The leading end stopper 18 is movable according to the sheet size of the sheet 3 conveyed to the conveying path 4, and when the sheet 3 conveyed on the conveying path 4 is A3 size, the position indicated by the solid line in FIG. When the paper 3 transported along the transport path 4 is of B4 size, FIG.
(A) is set to the position indicated by the dashed line.

The branching claw 8 guides the sheet 3 conveyed in the conveying path 4 to the leading end stopper 18 or the collating section 9 side. Specifically, the leading end of the sheet 3 is
In the first state (the position indicated by the solid line in FIG. 3A)
And a second state (a position shown by a dashed line in FIG. 3A) in which the leading end of the sheet 3 is guided to the collating section 9. Further, a reversing roller 19 is provided near the branch claw 8 along the transport path 4. The branch claw 8 is driven by a solenoid 44 (see FIG. 8).

Hereinafter, the operation of the single sheet folding section 7 will be described. The first roller 14 and the third roller 17 rotate, and the paper 3 is transported in the transport direction. In this state, the second roller 15 that is in pressure contact with the first roller 14 rotates in the direction opposite to the rotation direction of the first roller 14,
Is smaller by several sheets than the diameter of the first roller 14, so that the conveyance of the sheet 3 is not hindered. In this sheet conveyance state, the branching claw 8 pushes the sheet 3 to the leading end stopper 1.
The first state is set to guide the sheet 3 to the side 8, and the reversing roller 19 is rotating in the direction of transporting the sheet 3 in the transport direction.

As the sheet 3 is conveyed, the leading end of the sheet 3 hits the leading end stopper 18, but the rotation of the first roller 14 and the third roller 17 is continued thereafter. For this reason, although the leading end of the paper 3 is regulated, the central portion 3a of the paper 3 is sent in the transport direction, and the central portion 3a of the paper 3 is
Is bent (see FIG. 3B). When the leading end of the sheet 3 hits the leading end stopper 18, the rotation of the reversing roller 19 is stopped.

By the way, the first roller 14 rotates so as to convey the sheet 3 in the conveying direction, and the second roller 15 rotates in the opposite direction. In other words, the two rollers 14 and 15 4 is rotating in a direction to take in the sheet 3 existing between the first roller 14 and the second roller 15. Thereafter, when the amount of bending of the paper 3 increases, the central portion 3a is taken in between the first roller 14 and the second roller 15 (see FIG. 3C).

The paper 3 has a first roller 14 and a second roller 15
, A fold 31 is formed in a direction orthogonal to the transport direction of the paper 3. In this way, by taking the paper 3 between the first roller 14 and the second roller 15 pressed against each other, the fold 31 can be reliably formed on the paper 3 in the transport path 4. In the single sheet folding section 7 having this configuration, the diameter of the second roller 15 is
Since the thickness of the paper 3 is smaller than the diameter of the paper 3 only by the thickness of three papers, the paper 3 to be taken is hardly wrinkled. The pressing force between the first roller 14 and the second roller 15 is 1
It is sufficient that the force is sufficient and sufficient to make the fold 31 on the sheets of paper 3.

Thereafter, the rotation of the first roller 14 and the second roller 15 is continued, and the first roller 14 and the second roller 1 are rotated.
5, the sheet 3 protrudes to the side opposite to the conveying path 4 side, and the leading end of the sheet 3 moves in the direction opposite to the conveying direction. Then, the reversing roller 19 is idled in the reverse direction by being dragged by the sheet 3. During the operation of the single sheet folding section 7, the tip of the fold 31 is moved by the position sensor 16 to the two rollers 14, 15.
It has been examined whether the amount protruding from the center of has reached a predetermined amount.

When the amount reaches a predetermined amount,
The first roller 14 and the second roller 15 rotate in the opposite directions, and the sheet 3 is returned to the transport path 4 (see FIG. 3D).
At the same time as the first roller 14 and the second roller 15 rotate in the reverse direction, the branch claw 8 is switched from the first state to the second state, and the reversing roller 19 starts rotating in the direction for transporting the paper 3 in the transport direction. I do.

After the paper 3 is returned to the transport path 4, the first roller 14 and the third roller 17 are reversed and rotate in a direction for transporting the paper 3 in the transport direction. Paper 3 transported in the transport direction by first roller 14 and third roller 17
Is guided to the collating portion 9 by the branch claw 8 in the second state (see FIG. 3E). FIG. 4 is an illustrative sectional view showing another configuration example of the single-sheet folding section. With reference to FIG. 4, another configuration of the single sheet folding unit will be described.

The single sheet folding section 21 contacts a pair of folding rollers 22, 22 arranged in the transport direction of the sheet 3, a reversing roller 23 disposed along the transport path 4, and the reversing roller 23. And a press roller 24 for nipping the paper 3. Conveying path 4 for a pair of folding rollers 22
On the side, the central portion 3a of the paper 3 is
A first protruding blade 26 is provided between the pair of folding rollers 22 and 22, and an ironing portion 28 is provided on a side opposite to the transport path 4 side when viewed from the pair of folding rollers 22 and 22.

The pair of folding rollers 22, 22 can be moved to a position where they come into contact with each other, and the pressing roller 24 can be moved between a position where it comes into contact with the reversing roller 23 and a position where it does not come into contact. ing. The transport path 4 has a pair of feed rollers 2 for transporting the sheet 3 along the transport path 4.
7, 27 are arranged. Although it is preferable that the branching claw and the reversing roller shown in FIG. 3 are also provided in the single-sheet folding section 21 in FIG. 4, they are omitted because they have no direct relation to the features of the configuration in FIG.

Hereinafter, the operation of the single sheet folding section 21 will be described. A pair of feed rollers 27, 27, and a press roller 24;
Then, the reversing roller 23 rotates, and the sheet 3 is fed in the transport direction (see FIG. 4A). Then, when the leading end of the sheet 3 hits the leading end stopper 18, the pressing roller 24 moves so as not to come into contact with the reversing roller 23 (FIG. 4).
(B)).

Simultaneously with the movement of the press roller 24, the pair of folding rollers 22 and 22 move so as to abut each other, and also move the sheet 3 existing in the conveyance path 4 between the pair of folding rollers 22 and 22. Start rotation in the direction to take in. At this time, the rotation of the pair of feed rollers 27, 27 is continued, and in this state, the first protruding blade 26 protrudes toward the transport path 4 side. A first protruding blade 26 is applied to the central portion 3a of the paper 3 slightly loosened by the feed roller 27, and the central portion 3a of the paper 3 is brought into a pair of folding rollers 22, 22.
Captured during.

By passing between the pair of folding rollers 22, a fold is formed in the central portion 3 a of the sheet 3. Thereafter, the central portion 3a of the sheet 3 that has passed between the pair of folding rollers 22 protrudes to the side opposite to the transport path 4 side.
When the amount by which the bent edge 32 protrudes from the center of the pair of folding rollers 22 reaches a predetermined amount, the ironing unit 2
8 folds the folded edge 32 of the sheet 3 (FIG. 4).
(C)). At this time, the pair of folding rollers 22
Then, the rotation of the pair of feed rollers 27, 27 is stopped.

FIG. 5 is a perspective view showing the structure of the ironing section 28. As shown in FIG. The ironing portion 28 includes a pair of folding rollers 22, 22.
The ironing process is performed on the bent edge 32 formed by passing through the gap. More specifically, the ironing unit 28 includes an ironing table 29 and an ironing roller 30 pressed against the ironing table 29. In the ironing process, the folding edge 32 of the paper 3 is attached to the ironing table 29. The pressing is performed, and in this state, the ironing roller 30 is moved along a plane substantially orthogonal to the transport direction.

As described above, the sheet 3 is
Since the fold 32 of the paper 3 is stiff, the fold 31 can be firmly formed on the paper 3, and the fold 31 does not disappear even when the paper 3 is returned to the transport path 4 and straightened. This makes it easier to fold after collation. Thereafter, the contact between the pair of folding rollers 22, 22 is released, and the folding rollers 22, 22 return to the original separated state (see FIG. 4D).

In accordance with the release of the pair of folding rollers 22, 22, the pressing roller 24 moves the reversing roller 2.
3, and the rotation of the pair of feed rollers 27, 27 is resumed thereafter. The sheet 3 is transported by the pair of folding rollers 27, 27, the pressing roller 24, and the reversing roller.
Sent up. In addition, this ironing part 28 may be provided in the single sheet folding part 7 of FIG.

Referring again to FIG. 1, the sheets 3 that have been creased one by one are then gathered by a gathering unit 9. The paper 3 guided to the collating unit 9 is a brush roller 33 (FIG. 1).
(Refer to (1)), it is surely set to the collating portion 9. The collating unit 9 includes a collating table 35 inclined obliquely, a paper feeding belt 36 provided on the collating table 35, and a first stopper 34 provided on the paper feeding belt 36. .

FIG. 6 is an illustrative view showing a state in which the sheets 3 having the folds 31 formed in the collating section 9 are collated. Among the plurality of sheets 3 to be collated by the collating unit 9, the paper 3 to be sent to the collating unit 9 first is set on the collation table 35, and the paper 3 to be fed next on this paper 3 Are sequentially stacked.

The first stopper 34 is arranged at the lower end of the collating section 9. The first stopper 34 is tilted slightly obliquely with respect to the collation table 35 to which the paper 3 is collated so that the end of the paper 3 is collimated beforehand at the time of collation. . As described above, the amount of cutting by the cutter 5 increases as the paper 3 comes later, so that the paper 3 collated by the collating unit 9 is shorter as it is positioned higher, but the lower end of the paper 3 is inclined. The folds 31 are aligned by collating so that

The first stopper 34 can be moved in accordance with the size of the paper 3. When the paper 3 is A3 size, the position shown by a solid line in FIG. At the position shown by the dashed line.
The binding device 10 is a stapler. Single sheet folding part 7
A staple is driven in along the fold line 31 formed by the above, and a plurality of sheets 3 are bound. The sheet bundle bound by the collating unit 9 and bound by the closing device 10 is sent to the folding unit 11 by the rotating paper feeding belt 36.

FIG. 7 is an illustrative view for explaining the structure of the folding section 11. As shown in FIG. Referring to FIG. 7A, the folding unit 1
1 is a pair of folding rollers 40, 40 and a second protruding blade 4 for guiding the paper 3 between the folding rollers 40, 40.
1 and a second stopper 42 for regulating the leading end position of the sheet bundle. The second stopper 42 is slightly inclined in the same manner as the first stopper 34. The second stopper 42 reliably regulates the leading end position of the sheet bundle whose end portion is inclined.

The second stopper 42 is connected to the first stopper
Like the stopper 34, it can be moved according to the paper size of the paper 3, and when the paper 3 is A3 size, FIG.
(A) and the position indicated by the solid line in FIG.
When the size is four, the position is indicated by a dashed line in FIG. 7B. When the sheet bundle is folded, as shown in FIG. 7B, the second protruding blade 41 is connected to the pair of folding rollers 4.
0, 40 side, and the sheet bundle is
Captured during 40. Then, by passing between the pair of folding rollers 40, 40, the sheet bundle
Fold along 1

The bundle of sheets set in the folding section 11 is such that the upper sheet 3 which is positioned inside after folding,
Its length has been shortened. Accordingly, as shown in FIG. 7B, when the sheet bundle is folded, the ends of the folded sheet bundle are aligned neatly. FIG. 8 is a block diagram illustrating a configuration of a control circuit of the paper folding device 1 according to this embodiment.

A series of bookbinding operations such as fold formation, collation, and binding are executed under the control of the CPU 61. CP
The copying machine 2 is connected to U61.
1, a signal of the sheet size and a signal of the number of sheets to be bound are input from the copying machine 2. Further, a counter 62 for measuring the number of sheets sent to the transport path 4 and the like is connected to the CPU 61.

Further, based on the control program and each input signal, the CPU 61 drives / stops the first roller 14 and switches the rotation direction, the cutting operation by the cutter 5, the switching of the branch claw 8, the movement of the tip stopper 18, The operation of the collating unit 9 and the folding unit 11 is controlled. Although the paper size signal is input from the copying machine 2, a paper size detector is provided at the entrance, and the paper size of the paper 3 conveyed from the paper size detector is input. You may.

FIG. 9 is a flowchart showing an example of the control performed by the CPU 61. This paper folding device 1
First, the copy machine 2 sends a sheet number signal K and a sheet size signal. Among them, the leading end stopper 18, the first stopper 34 and the second stopper 4 according to the sheet size signal.
2 is set (steps S1 and S2).

Next, when the sheet 3 is sent to the transport path 4,
The count is counted by a counter 62 built in the PU 61 (steps S3 and S4). Then, so-called skew correction is performed by the registration roller pair 6, and the rear end of the sheet 3 is cut by the cutter 5 one by one (step S3).
5, S6). As described above, since the edge of the paper 3 is cut one by one, the cutter 5 may be small, and the paper folding device 1 may be used.
Does not increase in size as a whole.

The cutting timing of the cutter 5 will be described. The sheet 3 sent first is not cut by the cutter 5, but the cutting amount of the sheet 3 sent thereafter increases sequentially. In other words, when the number of sheets 3 to be collated is plural, the end is cut more by the cutter 5 as the sheet 3 comes later. More specifically, the cutting amount increases in proportion to the predetermined amount x later. For example, if x = 1 mm, the first sheet is not cut, but the cut amount of the second sheet is 1
mm, and the cutting amount of the third sheet is 2 mm. Here, 1 mm has been described as an example, but the amount of x is arbitrary.
Also, the cut amount of the sheet 3 has been described as increasing sequentially as the sheet is later. For example, the cut amount of the first to third sheets is 1 mm, the cut amount of the fourth to sixth sheets is 2 mm, and the cut amount of the The cutting amount may be increased every plural sheets, such as the cutting amount of the sheet is 3 mm.

Next, a fold 31 is formed on the sheets 3 one by one by the single sheet folding section 7 (step S7), and a predetermined number of sheets 3 are They are collated so that they are aligned (step S8).
The operations of steps S3 to S8 are repeatedly executed until a predetermined number of sheets 3 are collected in the collating section 9 (step S9).

When a predetermined number of sheets are collected in the collating section 9 (YES in step S9), the fold 3 of the collated paper 3
A stapling is performed by the binding device 10 along the line 1 (step S10). Thereafter, the sheet bundle is folded into two by the folding unit 11 (step S11), and a series of bookbinding operations is completed. Each sheet 3 is 1 in the single sheet folding section 7.
Since the folds 31 are provided for each sheet, the sheet bundle can be easily folded along the folds 31 provided in advance.

In addition, various design changes can be made within the scope of the matters described in the claims.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a paper folding device according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a configuration of a cutter.

FIG. 3 is a diagram illustrating a configuration and an operation of a single sheet folding unit.

FIG. 4 is a diagram illustrating another configuration example of the single sheet folding unit.

FIG. 5 is a perspective view showing a configuration of an ironing unit.

FIG. 6 is an illustrative view showing a state where sheets are collated at a collating unit;

FIG. 7 is an illustrative view for explaining a configuration of a folding unit;

FIG. 8 is a block diagram illustrating a configuration of a control circuit of the paper folding apparatus according to the embodiment.

FIG. 9 is a flowchart illustrating an example of control performed by a CPU.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper folding apparatus 2 Copier 3 Paper 3a Central part 4 Conveying path 5 Cutter (cutting means) 7 Single sheet folding part (fold forming means) 9 Collating part (collating means) 10 Binding device (binding means) 11 Folding part (Folding means) 14 First roller 15 Second roller 28 Ironing part (ironing means) 32 Folded edge

Claims (6)

[Claims] 1. A conveyance path on which sheets are conveyed one by one, crease applying means for creases each sheet conveyed on the conveyance path in a direction orthogonal to the conveyance direction of the sheet, A collating means for collating the specified number of sheets so that the fold position of each sheet is aligned; a binding means for performing binding processing along the crease of the collated paper; Folding means for folding a number of sheets along a fold. 2. The paper folding device according to claim 1, wherein the fold applying means has a first roller and a second roller arranged in a direction in which the paper is conveyed. Is that the line connecting the center axes of both rollers is parallel to the transport path, and the peripheral surfaces of both rollers are in contact with each other with a predetermined pressure. By rotating both rollers so that the central portion in the transport direction is taken in between the first roller and the second roller, and the sheet passes between the first roller and the second roller, a fold is formed in the central portion. A sheet folding device for rotating the first roller and the second roller in opposite directions to return the sheet to the transport path. 3. The paper folding device according to claim 2, wherein the first roller also serves as a roller for transporting a sheet along a transport path, and wherein the second roller has a diameter of the first roller. Characterized in that the diameter is smaller than the diameter of the paper folding device so as not to contribute to the paper conveyance. 4. The ironing device according to claim 2, wherein the folding edge of the sheet taken between the first roller and the second roller and passed between the two rollers is subjected to an ironing process. A paper folding device, further comprising: 5. The paper folding apparatus according to claim 1, further comprising cutting means for cutting an end of the sheet conveyed in the conveying path in the conveying direction, wherein the cutting means is collated. The cutting is performed by sequentially changing the cutting amount of a plurality of sheets so that the length of the sheet positioned inside after folding is shorter than the length of the sheet positioned outside after folding. Paper folding device. 6. The paper folding apparatus according to claim 1, wherein the collating means collates the collated paper so that the edge of the collated paper does not shift obliquely when the collated paper is folded. A paper folding apparatus characterized in that the edges of the paper are sometimes shifted obliquely in advance and collated.