JP4701151B2 - Sheet folding apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet folding apparatus and an image forming apparatus provided in an image forming apparatus such as a copying machine, a printer, and a printing machine.

A sheet post-processing device that is disposed downstream of the image forming apparatus main body and performs post-processing such as binding on output recording paper is widely known. In addition, saddle stitching processing is also generalized, and means for improving the folding quality of booklets that have undergone saddle stitch folding processing have been proposed as means for improving output quality (see, for example, Patent Documents 1 to 5).
Patent Document 1 discloses a folding device that performs a crease process with a pressure roller disposed at a predetermined angle downstream after a crease is formed by a pair of folding rollers and a protruding plate. It is intended to improve the folding quality by locally applying pressure to the folding part to increase the pressing force per unit length.
Patent Document 2 discloses a technique for improving the folding quality by providing means for applying heat and pressure to the fold. Further, Patent Documents 3 and 4 disclose a technique in which a pair of folding rollers are rotated forward and backward to perform multiple diffractions, and the number of reciprocating folds is increased as the number of sheets increases.
Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique aiming at an additional folding effect by moving an additional folding roller in a direction orthogonal to the sheet conveyance direction and locally pressing the folding unit.
JP 2001-261220 A Japanese Patent Laid-Open No. 9-326315 JP-A-9-183568 Japanese Patent No. 3254363 JP 2004-59304 A

However, the configuration of Patent Document 1 can surely improve the folding quality. However, when the paper is conveyed across both the pressure roller and the additional folding roller, the paper conveyance direction is different. Slippage may occur, and the output quality may be seriously affected, such as contamination of the image surface and, in the worst case, tearing of the paper.
In order to eliminate the above, there is a method in which the distance between the pressure rollers is increased and the pressure is applied by the downstream roller after passing through the nip of the upstream pressure roller. .
As another means, there is a method of releasing the nip of the upstream pressure roller before being sandwiched by the downstream pressure roller and eliminating the conveyance force, but it is difficult to set the paper conveyance timing at the time of delivery, Transport reliability is poor.

In the configuration of Patent Document 2, not only power is consumed, but also a heating roller, a control means for controlling temperature, and the like are required, resulting in high cost. Further, the configurations of Patent Documents 3 and 4 have a problem that the processing time increases and the productivity decreases as the number of times increases. Furthermore, in the configuration of Patent Document 5, the sheet bundle must be stopped when the additional folding roller is reciprocated, resulting in poor productivity.
In view of the above situation, the object of the present invention is to perform the middle folding process with the first pressure roller, separate the pressure roller in this state, release the pressure of the paper, and The plate is turned diagonally on the plate, the pressure roller is re-pressurized, and the paper is fed to the additional folding roller in an inclined state. By making it variable, the paper folding device, the paper conveying device, the paper post-processing device including the same, and the image forming device having a reliable middle folding means with short processing time, compact and low cost, high output quality, and high reliability Is to provide.

In order to solve the above problems, the invention according to claim 1 is characterized in that a first folding roller that presses and folds the sheet bundle passing through the nip, the downstream of the sheet bundle in the conveying direction, and the first bundle A second folding roller for further folding the folded sheet bundle at a position parallel to the folding roller, and a push for pushing the sheet bundle into a nip between the first folding roller and the second folding roller And a sheet folding apparatus comprising an oblique moving means for skewing the sheet bundle by tilting and moving the pushing means before the additional folding.
According to a second aspect of the present invention, there is provided the sheet folding device according to the first aspect, wherein the oblique moving means tilts the pushing means to move by changing a moving amount at both ends of the pushing means.
According to a third aspect of the present invention, there is provided the sheet folding device according to the first or second aspect, further comprising pressure release means for releasing pressure applied to the first folding roller during the operation of the oblique movement means. .

According to a fourth aspect of the present invention, there is provided control means for controlling the oblique movement means so as to change an amount of skew according to the number of the sheet bundle folded by the first folding roller. The sheet folding device according to any one of claims 1 to 3 is characterized.
According to a fifth aspect of the present invention, the control means causes the oblique movement means to increase the skewing amount as the number of the sheet bundles folded by the first folding roller increases. The sheet folding device according to claim 4 is controlled.
The invention according to claim 6 is a sheet folding device according to any one of claims 1 to 5, further comprising a single drive source for driving the first folding roller and the second folding roller. It is characterized by.
According to a seventh aspect of the present invention, there is provided an image forming apparatus including the paper folding device according to the sixth aspect.

  According to the present invention, the middle folding process is performed by the first folding roller (folding roller), the first pressure roller is separated in this state, the pressure of the sheet is released, and the sheet is fed by the folding plate. , And the first pressure roller is re-pressurized, and the sheet is conveyed to the second folding roller (additional folding roller) in an inclined state. In some cases, the folded portion is conveyed obliquely, and does not require a great amount of pressure as in the conventional additional folding. Therefore, the driving force is small and the structure can be greatly simplified. Furthermore, by making the skew amount variable depending on the number of half-folded sheets, the processing time is short, compact, low cost, high output quality and high reliability can be achieved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an image forming system including a sheet post-processing apparatus and an image forming apparatus according to an embodiment of the present invention. In FIG. 1, only parts necessary for understanding the present invention are described with reference numerals.
The sheet post-processing apparatus PD is attached to the downstream side of the image forming apparatus PR, and the sheet as a recording medium discharged from the image forming apparatus PR is introduced into the sheet post-processing apparatus PD. The sheet post-processing apparatus PD can perform processing such as punching, sheet alignment + edge binding, sheet alignment + saddle binding, sheet sorting, and folding on the sheet.
Since the center folding process will be mainly described, description of each part other than necessary for this purpose will be omitted. The sheet on which the folding process is performed is sent to the folding process tray G via the sheet bundle deflection mechanism of the staple processing tray F. The sheet bundle deflection mechanism includes a branch guide plate 1 and a movable guide plate 2.
FIG. 1 further shows a folding plate (pushing means) 3, an upper bundle conveyance guide plate 4 and a lower bundle conveyance guide plate 5, a first folding roller (folding roller) 6, a folding portion passage sensor 7, and a second folding. A roller (additional folding roller) 8, a lower discharge sensor 9, a lower discharge roller 10, a lower discharge tray 11, a movable rear end fence 24, and a lower bundle conveying roller 23 are shown.

2 is an enlarged schematic view showing only the vicinity of the middle folding device of FIG. 1 according to the embodiment of the present invention. FIG. 3 is an enlarged schematic view showing only the vicinity of the center folding apparatus to which the configuration according to the present invention is added.
First, in FIG. 2, the first folding roller 6 is disposed after the folding portion passage sensor 7 with the upper bundle conveyance guide plate 4 and the lower bundle conveyance guide plate 5 interposed at a position facing the folding plate 3. 2 shows a lower discharge tray 11 on which a bundle of sheets is discharged and accumulated through a folding roller 8 and a lower discharge sensor 9 and a lower discharge roller 10.

According to FIG. 3, the first folding roller 6 supports a pressure release lever (pressure release means) 12 for releasing the applied pressure, and the pressure release lever 12 is rotatable about a fulcrum 13. is there.
On the other hand, the pressure release lever 12 is provided with a long hole 12a. In this long hole 12a, a pin 15 disposed parallel to the rotation shaft 14a of the cam 14 is disposed, and is fitted into the long hole 12a. ing.
The cam 14 is driven by a drive motor 17 via a timing belt 16. As the drive motor 17 is driven, the cam 14 rotates, the pin 15 rotates clockwise in the circumferential direction, and the pressure release lever 12 moves. By rotating, the first folding roller 6 is pushed up, and the applied pressure is released.
The first folding roller 6 is normally in a pressurized state, but the home position is detected when the home position sensor 18 detects the protrusion provided on the cam 14. Further, the conveyance driving of the first folding roller 6 and the second folding roller 8 is driven by a folding roller drive motor 19 and is driven synchronously by a timing belt 20.

FIG. 4 is a top view showing the first folding roller 6, the second folding roller 8, and the folding plate 3. FIG. 5 is a top view showing the first folding roller 6, the second folding roller 8, and the sheet bundle. In FIG. 4, the folding plate 3 is provided with an oblique moving means including a first folding mechanism 21 and a second folding mechanism 22 so as to be able to move away from the first folding roller 6. It is configured so that the position of moving toward and away from the folding roller 6 can be independently controlled.
With such a configuration, by changing the amount of movement of both ends of the folding plate 3, the folding plate 3 is pushed in a state inclined with respect to the sheet bundle (a state indicated by a chain line in FIG. 3), thereby rotating the sheet to a skew state. it can. Although this is disadvantageous in terms of cost and space, the same effect can be obtained even if a dedicated gripper is provided and rotated while gripping the paper.
Note that the skew amount θ increases as the pressing force per unit length with respect to the crease increases, so that the increasing folding effect increases. In the embodiment, the skew amount θ gradually increases to 0 to 20 ° as the number of sheets increases. Is set to

FIG. 6 is a schematic diagram for explaining the operation of the first folding roller 6, the second folding roller 8, and the lower paper discharge roller 10 along the sheet flow. FIG. 7 is a flowchart for explaining the operation of the folding device. FIG. 8 is a flowchart for explaining the operation of controlling the skew amount according to the number of folded sheets.
According to FIGS. 6 to 8, the sheet bundle abutted against the movable rear end fence 24 (see FIG. 1) is released from the pressure of the lower bundle conveying roller 23 (S1), and is then stapled near the needle portion. Is pushed in a substantially right angle direction by the folding plate 3 that has started operation (S2), and is guided to the nip of the first folding roller 6 that is opposed. At this time, the second folding roller 8 and the lower paper discharge roller 10 have also started to operate (S3).
The first folding roller 6 rotating in advance folds the center of the sheet bundle by conveying the sheet bundle guided to the nip under pressure (a and b in FIG. 6). It is determined whether or not the folding section passage sensor 7 is on (S4). If it is on, the first and second folding rollers 6 and 8 and the lower folding rollers 6 and 8 are lowered when the end of the folding section reaches the folding section passage sensor 7. The operation of the paper discharge roller 10 is stopped (S5) (c in FIG. 6).

Next, as a pre-stage for skewing the paper, the pressure of the first folding roller 6 is released to make the paper free (c in FIG. 6) (S6). At this time, the folding operation of the folding plate 3 is started based on the number counting means (not shown), and the direction of the folded portion of the sheet is changed to an oblique state (S7).
Next, in order to prepare the sheet, the lower bundle conveying roller 23 (see FIG. 1) is pressurized (S8), and then the folding plate 3 moves to the home position (S9), and the first folding roller 6 is added. Pressure is applied (S10), the first and second folding rollers 6 and 8 and the lower paper discharge roller 10 are started to be driven (S11), and the sheet crease portion is inclined to the second folding roller 8. The sheet enters (d in FIG. 6), and the sheet is further folded.

When the folding plate 3 is obliquely moved as in step (S7) in FIG. 7, the number of folded sheets is counted by a number counting means (not shown) (S21), the position of the folded plate 3 is determined (S22), The folding plate 3 is moved to the front and rear drive designation positions by the first folding mechanism 21 and the second folding mechanism 22 (FIG. 4) (S22), and the direction of the folded portion of the sheet is changed to an oblique state.
Although the conveyance drive of the first and second folding rollers 6 and 8 is the same drive, since the sheet is only conveyed obliquely, the load is not applied to the sheet as in the case of Patent Document 1, and smooth. Can be transported.
The paper folding device of the present invention can be applied to a paper post-processing device. The sheet post-processing apparatus can be applied as a part of an image forming apparatus such as a copying machine, a printer, or a facsimile machine.

1 is a schematic diagram illustrating an image forming system including a sheet post-processing apparatus and an image forming apparatus according to an embodiment of the present invention. The schematic diagram which expands and shows only the middle folding apparatus vicinity of FIG. Schematic which expands and shows only the center folding apparatus vicinity which added the structure by this invention. The top view which shows a 1st folding roller and a folding plate. FIG. 3 is a top view showing a first folding roller and a sheet bundle. Schematic explaining operation | movement of a 1st folding roller, a 2nd folding roller, and a bundle conveyance roller along the flow of a paper. The flowchart explaining operation | movement of a middle folding apparatus. 6 is a flowchart for explaining an operation of controlling the skew amount according to the number of folded sheets.

Explanation of symbols

  PD paper post-processing device, PR image forming device, 3 folding plate, 6 folding roller (first folding roller), 8 additional folding roller (second folding roller), 12 pressure release lever, 19 folding roller drive motor, 21 Diagonal moving means (first folding mechanism), 22 Diagonal moving means (second folding mechanism)

Claims (7)

A first folding roller that presses and folds the sheet bundle that passes through the nip, and is added to the folded sheet bundle at a position downstream in the conveyance direction of the sheet bundle and in parallel with the first folding roller. In a paper folding apparatus comprising: a second folding roller for folding; and a pushing means for pushing the bundle of paper into a nip between the first folding roller and the second folding roller;
A sheet folding apparatus comprising oblique moving means for skewing the sheet bundle by tilting and moving the pushing means before additional folding.   2. The sheet folding apparatus according to claim 1, wherein the oblique moving means tilts and moves the pushing means by changing a moving amount at both ends of the pushing means.   3. The sheet folding apparatus according to claim 1, further comprising a pressure releasing unit that releases the pressure applied to the first folding roller during the operation of the oblique moving unit.   4. The apparatus according to claim 1, further comprising a control unit that controls the oblique moving unit so as to change an amount of skewing according to the number of the sheet bundle folded by the first folding roller. The sheet folding device according to any one of the above.   5. The control unit according to claim 4, wherein the control unit controls the oblique movement unit to increase a skewing amount as the number of the sheet bundles folded by the first folding roller increases. Paper folding device.   6. The sheet folding apparatus according to claim 1, further comprising a single drive source that drives the first folding roller and the second folding roller.   An image forming apparatus comprising the sheet post-processing apparatus according to claim 6.

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