JP2013001543A - Sheet folding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet folding device capable of heating the folding part of a sheet with an appropriate quantity of heat for the thickness of an actual sheet bundle.SOLUTION: A temperature controller determines a heating condition to a heating device on the basis of a difference between an inter-roller first distance measured by an inter-roller distance measuring device when the sheet is pushed between a first folding roller and a second folding roller by a folding blade before rotation by the first folding roller and the second folding roller, and an inter-roller second distance measured by the inter-roller distance measuring device when a predetermined time elapses after the start of the heating of the first folding roller by the heating device.

Description

  The present invention relates to a sheet folding apparatus provided in a sheet post-processing apparatus that is employed in an image forming system.

  In the case of a sheet post-processing apparatus provided with a sheet folding apparatus including a pair of folding rollers for folding sheets in a bundled state, as the number of sheets increases, the folding degree (folding quality) when folded becomes lower. It is easy to have the harmful effect of opening again.

  In order to solve such problems, a technique for improving the degree of folding by heating a folded portion of a sheet is disclosed in Japanese Patent Application Laid-Open No. 2008-230814 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2007-084324 (Patent Document). Document 2) and Japanese Patent Laid-Open No. 11-157247 (Patent Document 3).

JP 2008-230814 A JP 2007-084324 A JP-A-11-157247

  However, if the heating time is increased for the purpose of improving the folding degree or the heating temperature is increased, the amount of heat supplied to the sheet bundle becomes excessive, and the toner formed on the sheet is remelted. Occurs.

  Conversely, if the heating time is shortened or the heating temperature is lowered in order to prevent remelting of the toner, there is a problem that the amount of heat supplied to the sheet bundle is insufficient and sufficient folding quality cannot be obtained. Therefore, it is necessary to manage the amount of heat given to the bundle of sheets appropriately.

  In order to make the amount of heat given to the sheet bundle appropriate, it is important to accurately grasp the state of the sheet bundle. However, due to sheet thickness errors, paper type differences, and the like, the actual sheet bundle thickness may differ from the sheet bundle thickness predicted from the job information obtained from the image forming system.

  When the thickness of the sheet bundle is smaller than the actual thickness of the sheet bundle, the supply heat amount becomes excessive, and the toner may be remelted. In addition, when the thickness of the sheet bundle is thicker than the actual thickness of the sheet bundle, the amount of supplied heat is insufficient, and there is a risk that the folding cost will be reduced.

  Furthermore, when the thickness of the sheet bundle is thin, it is considered that the folding process proceeds faster than expected. However, in actuality, a time heating process based on the thickness of the sheet bundle predicted from the job information is performed, which leads to a decrease in productivity.

  The present invention has been made to solve the above problems, and provides a sheet folding apparatus capable of heating a folded portion of a sheet with an appropriate amount of heat with respect to the actual thickness of a bundle of sheets. The purpose is to do.

  In the sheet folding apparatus according to the present invention, a sheet folding apparatus for folding a sheet, the folding blade for folding the sheet, and the first folding roller for sandwiching the sheet folded by the folding blade And a second folding roller, a heating device that heats the first folding roller, an inter-roller distance measuring device that measures the distance between the first folding roller and the second folding roller, and the inter-roller distance measurement. And a temperature control device for controlling the temperature of the heating device based on information obtained from the device.

  The temperature control device is configured so that the sheet is pushed between the first folding roller and the second folding roller by the folding blade before being rotated by the first folding roller and the second folding roller. The first inter-roller distance measured by the inter-roller distance measuring device, and the inter-roller distance when a predetermined time has elapsed after the heating of the first folding roller by the heating device is started. A heating condition for the heating device is determined based on a difference from the second distance between the rollers measured by the measuring device.

  In another embodiment, the temperature control device corrects the initial heating condition determined in advance according to the condition of the sheet based on information obtained from a difference between the first distance between the rollers and the second distance between the rollers. Then, the heating conditions are determined.

  In another embodiment, the temperature control device may be configured such that the distance between rollers is measured by the inter-roller distance measuring device in the middle of a predetermined time after the heating of the first folding roller by the heating device is started. The third distance is measured, and the heating condition is further corrected based on the difference between the first distance between the rollers and the third distance between the rollers.

  In another embodiment, the temperature control device may set the heating temperature by the heating device as a normal heating temperature when the second distance between the rollers is larger than a predetermined comparison distance as the heating condition. The heating time by the heating device is set longer than the normal heating time.

  In another form, the timing which sets the heating time by the said heating apparatus longer than normal heating time is after progress of normal heating time.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the sheet folding apparatus which can heat the folding part of a sheet | seat with appropriate heat quantity with respect to the thickness of the actual sheet | seat bundle.

1 is a diagram illustrating a schematic configuration of an image forming system including a sheet folding device in a sheet post-processing apparatus according to an embodiment. It is a figure which shows typically the internal structure of the sheet | seat post-processing apparatus in embodiment. It is a figure which shows the control block of the sheet | seat post-processing apparatus in embodiment. It is a schematic diagram which shows the folding operation | movement of the sheet | seat by the sheet folding apparatus in embodiment. It is a figure which shows a state when the bundle | flux of a sheet | seat is pushed in into the sheet folding apparatus in embodiment. It is a figure which shows a state when predetermined heating time passes, after the bundle | flux of a sheet | seat is pushed in into the sheet folding apparatus in embodiment. FIG. 3 is a diagram illustrating a sheet folding flow by the sheet folding apparatus according to the first exemplary embodiment. It is a figure which shows the relationship between the distance between rollers, heater heating temperature, and processing time by the sheet folding apparatus in Example 1. FIG. 10 is a diagram illustrating a sheet folding flow by the sheet folding apparatus according to Embodiment 2. FIG. It is a figure which shows the relationship between the distance between rollers, heater heating temperature, and processing time by the sheet folding apparatus in Example 2. FIG. 10 is a diagram illustrating a sheet folding flow by the sheet folding apparatus according to Embodiment 3. FIG. It is a figure which shows the relationship between the distance between rollers, heater heating temperature, and processing time by the sheet folding apparatus in Example 3. FIG.

  An image forming system including a sheet post-processing apparatus having a sheet folding apparatus according to an embodiment of the present invention will be described below with reference to the drawings. Note that in the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated. In addition, it is planned from the beginning to use the structures in the embodiments in appropriate combinations.

[1. Schematic configuration of image forming system]
FIG. 1 is a diagram showing a schematic configuration of an image forming system 1 including a sheet folding device 500 in a sheet post-processing device 50 according to the present invention, and FIG. 2 schematically shows an internal structure of the sheet post-processing device 50. FIG.

  Referring to FIG. 1, an image forming system 1 mainly includes an image forming apparatus 10 that forms an image on a sheet S such as paper, and a punching process, a staple needle process, and the like on a sheet S on which an image is formed. And a sheet post-processing device 50 that performs post-processing such as folding processing.

  The image forming apparatus 10 includes an automatic document feeder (ADF) 20 that performs automatic continuous conveyance of a document in a copy operation and a scan operation, a scanner 30 that generates image data of the document, and a scanner 30 that generates the image. And an image forming unit 40 that forms an image on the sheet S based on the image data or image data stored in advance.

  The image forming unit 40 supplies power supplied from an external AC power source to each part of the image forming apparatus 10 and the sheet post-processing apparatus 50, and image formation for overall control of the operation of the image forming apparatus 10. Device control unit 12.

  Referring to FIG. 2, in the upper region of sheet post-processing device 50, punch unit 510 that performs punch punching processing on sheet S sent from image forming apparatus 10, and flat binding processing using staples on sheet S are performed. A flat stitch stapler unit 551 and a paper discharge tray 580 are provided.

<Sheet folding device 500>
In the lower region of the sheet post-processing apparatus 50, a sheet folding apparatus 500 that performs a folding process on the sheet S is provided. The sheet folding apparatus 500 is provided at a lower end of a pair of conveying rollers 511 and 512 that convey the sheet S into the sheet folding apparatus 500, a support plate 520 that supports the sheet S from the back side, and a sheet A folding stacker 535 that aligns the lower ends of S is included.

  After a predetermined number of sheets S are stacked in the folding stacker 535, the sheets S are moved to the folding position after being subjected to saddle stitching by the saddle stitch stapler unit as necessary.

  An opening 520 h is provided in the support plate 520, and a folding blade unit 530 that creases the sheet S is provided in a region of the opening 520 h opposite to the sheet S conveyance side. The folding blade unit 530 has a folding blade 530B that passes through the opening 520h and creases the sheet S.

  In FIG. 2, the sheet before the crease is indicated by a solid line as the sheet S1, and the sheet extruded by the folding blade 530B and the crease is given is indicated by a two-dotted line as the sheet S2.

  A pair of first and second folding rollers 541 and 542 that fold the sheet S2 together with the folding blade 530B are provided at positions facing the opening 520h on the conveyance side of the sheet S. A heater 543 is provided inside the first folding roller 541 located on the upper side. The first folding roller 541 is provided with a temperature sensor 544 that detects the surface temperature of the first folding roller 541.

  A booklet tray 590 is provided in a lower part of the sheet folding apparatus 500, and the creased booklet is discharged onto the booklet tray 590 by a pair of first folding roller 541 and second folding roller 542.

  Further, a saddle stitch stapler unit 552 that performs a saddle stitch process on the sheet S with staples is provided on the upstream side of the pair of first and second folding rollers 541 and 542.

[2. Control block of sheet post-processing apparatus]
FIG. 3 shows a control block diagram of the sheet post-processing apparatus 50.

  With reference to FIG. 3, the sheet post-processing apparatus 50 can communicate with each other using the image forming apparatus control unit 12 of the image forming apparatus 10 and the communication line L1. The sheet post-processing device 50 includes a first central control unit 11A that controls the punch unit 510 and the saddle stitching stapler unit 552, and a second central control unit 11B that controls the sheet folding device 500 and the saddle stitching stapler unit 552. . The first central control unit 11A and the second central control unit 11AB can communicate with each other using the communication line L2.

  The first central control unit 11A includes, as control targets, a flat stitch stapler moving motor 551M, a drive motor / sensor 530M for the saddle stitch stapler unit 552, a punch motor / sensor 510M for the punch unit 510, a sheet alignment first motor 553M, and a sheet. Includes a matching second motor 554M. The first central control unit 11A receives sensor information from various sensors 501, a drive motor / sensor 530M, and a punch motor / sensor 510M.

  The flat stitch stapler moving motor 551M is controlled by the motor driver 551A based on a signal from the first central control unit 11A. The drive motor / sensor 530M is controlled by the saddle stitch stapler drive circuit 552A based on a signal from the first central control unit 11A. The punch motor / sensor 510M is controlled by the punch driving circuit 510A based on a signal from the first central control unit 11A.

  The sheet alignment first motor 553M is controlled by the motor driver 553A based on a signal from the first central control unit 11A. The sheet alignment second motor 554M is controlled by the motor driver 554A based on a signal from the first central control unit 11A.

  The second central control unit 11B includes a heater 543, folding roller driving motors 541M and 542M, a folding blade driving motor 531M, a sheet alignment motor 535M, a booklet tray lifting motor 590M, and a driving motor 552M for the saddle stitch stapler unit 552 as control targets. Including. The second central control unit 11B receives sensor information from various sensors 502. The second central control unit 11B receives information from the booklet tray lifting motor 590M.

  The heater 543 is controlled by the heater controller 543A based on a signal from the second central control unit 11B. Heater controller 543A receives sensor information from temperature sensor 544.

  In addition, the second central control unit 11B receives information from the distance sensor 545 that measures the distance L (see FIG. 4) between the first folding roller 541 and the rotation shaft 542a. Based on the information from the distance sensor 545, the second central control unit 11B measures the inter-roller distance between the first folding roller 541 and the second folding roller 542.

  Further, based on the information on the distance between the rollers, as shown in each example described later, the final heating condition of the sheet according to the sheet conditions (thickness, number of sheets, paper type, etc.) is determined. It is output to the heater controller 543A. Therefore, the second central control unit 11B includes a temperature control device for the heater 543.

  The folding roller drive motors 541M and 542M are controlled by the motor driver 541A based on a signal from the second central control unit 11B. The folding blade drive motor 531M is controlled by the motor driver 530A based on a signal from the second central control unit 11B. The sheet alignment motor 535M is controlled by the motor driver 535A based on a signal from the second central control unit 11B.

  The drive motor 552M of the saddle stitch stapler unit 552 is controlled by the saddle stitch stapler drive circuit 552A based on a signal from the second central control unit 11B. The second central control unit 11B receives information from the drive motor 552M.

(Folding operation by sheet folding device 500)
Next, the folding operation of the sheet S by the sheet folding apparatus 500 will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating a sheet folding operation by the sheet folding apparatus according to the embodiment.

  The end positions of the plurality of sheets S conveyed while being supported along the support plate 520 are aligned by the folding stacker 535 so that the central part of the sheet S is positioned to face the opening 520h. Thereafter, the folding blade 530B provided in the folding blade unit 530 is pushed out toward the pair of first folding roller 541 and second folding roller 542 so as to pass through the opening 520h.

  The sheet S pushed toward the pair of first folding roller 541 and the second folding roller 542 by the folding blade 530B is sandwiched between the nip portions n1 of the pair of first folding roller 541 and the second folding roller 542.

  The sheet S is heated by the heater 543 provided inside the first folding roller 541 and is sandwiched in a pressurized state by the pair of first folding roller 541 and the second folding roller 542. A fold is formed.

  When the sheet S is sent to the nip portion n1 of the pair of the first folding roller 541 and the second folding roller 542, the folded portion of the sheet S is heated by the heater 543 built in the first folding roller 541. This softens the fibers and improves the folding degree of the folded portion of the sheet S.

  Thereafter, the sheet S (booklet) on which the folds are formed is discharged onto the booklet tray 590 by the pair of first folding roller 541 and second folding roller 542.

  In addition, the distance sensor 545 is disposed below the second folding roller 542, and the distance between the rotation shaft 542a of the second folding roller 542 (roller axial distance L) is measured, thereby enabling measurement of the distance between the rollers. (For example, distance d1 in FIG. 5). By measuring the distance d1 between the rollers, the thickness of the bundle of sheets S in the gap where the bundle of sheets S is fed into the nip portion n1 of the pair of folding rollers can be measured.

  Thereby, it is possible to measure the actual thickness of the bundle of sheets S by setting the thickness of the bundle of sheets S to be predicted in advance based on the thickness error of the sheets S, the difference in the types of the sheets S, and the like. .

  In FIGS. 5 and 6, the distance between the folding rollers is changed from d1 to d2 with the change in the thickness of the bundle of sheets S when the bundle of sheets S is folded at the nip portion n1 of the folding roller. It shows how it changes.

  FIG. 5 shows a state when heating of the first folding roller 541 by the heater 543 is started, and FIG. 6 shows a state when heating is completed after a predetermined time has elapsed. What should be noted here is the change in the distance between the folding rollers described above. At the start of heating, the distance between the folding rollers was the distance d1 (first distance between the rollers). The distance between the rollers is as small as d2 (second distance between the rollers).

  This is because the thickness of the folded portion of the bundle of sheets S is reduced by applying heat and pressure to the bundle of sheets S. In the present embodiment, a change in the thickness of the folded portion of the bundle of sheets S (hereinafter referred to as “the bundle thickness of the sheet S”) is detected by the distance sensor 545 disposed below the second folding roller 542. It measures based on the distance (roller axial distance L1) with the rotating shaft 542a of the 2-fold roller 542.

  In the state shown in FIG. 5, based on the roller axial distance L1, the distance between rollers d1 is calculated in the second central control unit 11B. Similarly, in the state shown in FIG. 6, based on this roller axial distance L2, the distance between rollers d2 is calculated in the second central control unit 11B.

Example 1
Next, with reference to FIGS. 7 and 8, a sheet folding flow by the sheet folding apparatus 500 based on the present embodiment will be described. 7 is a diagram illustrating a sheet folding flow by the sheet folding apparatus 500 in the first embodiment, and FIG. 8 is a distance between rollers, a heater heating temperature, and a processing time by the sheet folding apparatus 500 in the first embodiment. It is a figure which shows the relationship.

  In the first exemplary embodiment, when the actual bundle thickness of the sheet S is different from the bundle thickness of the sheet S predicted in advance from the job information obtained from the image forming system, the heat amount appropriate for the bundle thickness of the sheet S is used. The initial heating condition determined in advance according to the conditions of the sheet S is corrected based on the information obtained from the difference between the first distance between rollers (d1) and the second distance between rollers (d2). The heating conditions are determined.

  As described above, when a bundle of sheets S is folded, a predetermined number of sheets S are stacked in the folding stacker 535 and an alignment operation is performed. Meanwhile, the bundle thickness of the sheet S is calculated from the job information, and the first distance (d1) between the rollers is derived in advance (step 10 (S10) in FIG. 7). Next, the heating time T1 is calculated from the calculated bundle thickness of the sheet S (step 20 (S20) in FIG. 7). Then, after the stacking of the sheets S is completed, the process proceeds to folding processing (step 30 (S30) in FIG. 7).

  In the folding process, a pair of the first folding roller 541 and the second folding roller 542 are fed in a state where the bundle of sheets S is sent to the nip portion n1 of the pair of first folding roller 541 and the second folding roller 542 by the folding blade 530B. Is stopped, heating of the first folding roller 541 by the heater 543 is started (step 40 (S40) in FIG. 7).

  In a state where the bundle of sheets S is fed to the nip part n1, the bundle of sheets S is heated for a certain time, and then the roller axial distance L2 is measured using the distance sensor 545, and the second distance (d2) between the rollers is determined based on this measurement result. Is calculated (step 50 (S50) in FIG. 7).

  The second inter-roller distance (d2) is compared with the first inter-roller distance (d1) calculated in advance from the job information (step 60 (S60) in FIG. 7). When the second distance between rollers (d2) and the first distance between rollers (d1) are the same (step 130 (S130) in FIG. 7), the bundle of sheets S is heated until the time T1 calculated in advance (FIG. 7). 7 (step 140 (S140)), the heating is stopped when the time T1 has elapsed (step 150 (S150) in FIG. 7).

  Thereafter, as shown in FIG. 8, the process waits for the processing time (1) considering heating due to residual heat (step 160 (S160) in FIG. 7), and the pair of first folding rollers after the processing time (1) has elapsed. 541 and the second folding roller 542 are rotated. Thereafter, the bundle of sheets S is discharged to the booklet tray 590 (step 120 (S120) in FIG. 7), and the folding process is completed.

  On the other hand, the second inter-roller distance (d2) is compared with the first inter-roller distance (d1) calculated in advance from the job information (step 60 (S60) in FIG. 7), and the second inter-roller distance (d2) and the roller If the first distance (d1) is different, the heating time is corrected from T1 to T2 according to the difference (step 70 (S70) in FIG. 7), and heating is started (step 80 (FIG. 7)). S80)).

  After the start of heating, the process waits for the heating time T2 to elapse (step 90 (S90) in FIG. 7), and stops heating when the time T2 elapses (step 100 (S100) in FIG. 7). Further, as shown in FIG. 8, the process waits for the processing time (2) considering the heating due to residual heat (step 110 (S110) in FIG. 7), and after the processing time (2) elapses, The roller 541 and the second folding roller 542 are rotated. Thereafter, the bundle of sheets S is discharged to the booklet tray 590 (step 120 (S120) in FIG. 7), and the folding process is completed.

  As described above, the heating time is corrected according to the thickness of the bundle of sheets S, and the amount of heat applied to the bundle of sheets S is made appropriate, so that the re-melting of the toner does not occur while ensuring the folding quality. It becomes possible to do so.

  When the thickness of the bundle of sheets S is thinner than expected (for example, d1> d2), the heating time can be shortened. Therefore, as shown in FIG. 8, the folding processing time is equal to the processing time (1). Therefore, the processing time is shortened to (2), and productivity can be improved.

(Example 2)
Next, a sheet folding flow by the sheet folding apparatus 500 according to the second embodiment will be described with reference to FIGS. 9 and 10. 9 is a diagram illustrating a sheet folding flow by the sheet folding apparatus 500 according to the second embodiment. FIG. 10 illustrates a distance between rollers, a heater heating temperature, and a processing time by the sheet folding apparatus 500 according to the second embodiment. It is a figure which shows the relationship.

  Moreover, the same process number as Example 1 is attached | subjected, and the overlapping description is not repeated.

  In the processing flow in the second embodiment, the case where the folding process does not proceed as expected or the folding process proceeds faster than expected with respect to the process of correcting the heating time according to the actual sheet S bundle thickness. In view of this, during the folding process, the bundle thickness of the sheet S is measured again, and the heating time is corrected again according to the difference from the bundle thickness of the sheet S assumed from the job information.

  Specifically, the heating time T1 is corrected to T2 according to the actual bundle thickness of the sheet S, and after heating is started (step 80 (S80) in FIG. 9), after a preset time T3 has elapsed ( Step 200 in FIG. 9 (S200)), again, the distance sensor 545 measures the distance (roller axial distance) between the second folding roller 542 and the rotation shaft 542a, and the second central control unit 11B determines the distance between the rollers. d3 (third distance between rollers) is calculated.

  When the difference between the third roller distance d3 and the second roller distance (d2) is larger than a predetermined Δd (step 210 (S210) in FIG. 9), the heating time T2 is corrected to T4 again. Then, heat treatment is performed (step 220 (S220) in FIG. 9).

  After the start of heating, the process waits for the heating time T4 to elapse (step 230 (S230) in FIG. 9), and stops the heating when the heating time T4 elapses (step 240 (S240) in FIG. 9). Further, as shown in FIG. 10, the process waits for the processing time (3) considering the heating due to the residual heat (step 250 (S250) in FIG. 9), and after the processing time (3) elapses, The roller 541 and the second folding roller 542 are rotated. Thereafter, the bundle of sheets S is discharged to the booklet tray 590 (step 120 (S120) in FIG. 9), and the folding process is completed.

  As described above, the progress of the folding process is measured in the middle of the folding process, and the heating time is fed back, so that the re-melting of the toner is prevented while ensuring the folding quality with higher accuracy. It becomes possible. Further, as shown in FIG. 10, the folding processing time is shortened from the processing time (2) to the processing time (3), and the productivity can be improved.

(Example 3)
Next, a sheet folding flow by the sheet folding apparatus 500 according to the third embodiment will be described with reference to FIGS. 11 and 12. 11 is a diagram illustrating a sheet folding flow by the sheet folding apparatus 500 according to the third embodiment. FIG. 12 illustrates a distance between rollers, a heater heating temperature, and a processing time by the sheet folding apparatus 500 according to the third embodiment. It is a figure which shows the relationship.

  Further, the same processing steps as those in the first and second embodiments are denoted by the same step numbers, and redundant description will not be repeated.

  In the processing flow in the third embodiment, when the bundle thickness d3 of the sheet S measured again is larger than the assumed bundle thickness d4 of the sheet S at the time when the heating time T3 has elapsed, that is, the folding process. This refers to the case where the progress is bad.

  In order to reliably perform the folding process, the toner may be remelted by extending the heating time. However, this is avoided by lowering the heating temperature below the normal temperature. Specifically, the thickness d3 of the bundle of sheets S is measured again at the time when the heating time T3 has elapsed after the start of heating (step 200 (S200) in FIG. 11).

  When the measured thickness d3 of the bundle of sheets S is larger than the thickness d4 of the bundle of sheets S assumed when the heating time T3 has elapsed (step 300 (S300) in FIG. 11), the heating time is set to T2. To T4 (step 310 (S310) in FIG. 11), the heating temperature is lowered from H1 to H2 when the heating time T2 has elapsed (steps 320 and 330 (S320, S330) in FIG. 11), and the heating time T4 is reached. After the elapse of time, heating is stopped (steps 340 and 350 (S340 and S350) in FIG. 11).

  Furthermore, as shown in FIG. 12, the process waits for the processing time (4) considering the heating due to the residual heat (step 360 (S360) in FIG. 11), and after the processing time (4) passes, The roller 541 and the second folding roller 542 are rotated. Thereafter, the bundle of sheets S is discharged to the booklet tray 590 (step 370 (S370) in FIG. 11), and the folding process is completed.

  By adopting the sheet folding flow process, it is possible to prevent remelting of the toner while covering a state where the progress of the folding process is poor. Here, it is desirable that the heating temperature H2 is a temperature at which the toner does not remelt even if the heating is continued for a very long time.

  Also, the timing for switching the heating temperature H1 to H2 is preferably after the elapse of the heating time T2 calculated from the actual bundle thickness of the sheet S from the viewpoint of ensuring folding quality. This is because the time is originally determined from the premise that remelting of the toner does not occur.

  When the thickness d4 of the bundle of sheets S assumed when the heating time T3 has elapsed is smaller than the thickness d3 (step 300 (S300) in FIG. 11), step 220 (S220) of the second embodiment. It is good to move to.

  As described above, according to the sheet folding apparatus in the present embodiment, when the folding process does not proceed as expected with respect to the process of correcting the heating time according to the actual bundle thickness of the sheet S, the amount of heat is increased. By lowering and lengthening the heating time, a reliable folding process can be achieved and toner remelting can be prevented. As a result, it is possible to provide a sheet folding device that can heat the folded portion of the sheet S with an appropriate amount of heat with respect to the actual thickness of the bundle of sheets S.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Image forming system, 10 Image forming apparatus, 11A 1st central control part, 11B 2nd central control part, 12 Image forming apparatus control part, 20 Automatic document feeder (ADF: Auto Document Feeder), 30 Scanner, 40 Image formation Part, 50 sheet post-processing device, 100 power supply unit, 500 sheet folding device, 501 various sensors, 510 punch unit, 510A punch drive circuit, 510M punch motor / sensor, 511, 512 conveying roller, 520 support plate, 520h opening 530 folding blade unit, 530A motor driver, 530B folding blade, 530M drive motor / sensor, 531M folding blade drive motor, 535 folding stacker, 535A motor driver, 535M sheet alignment motor , 541 1st folding roller, 541A motor driver, 541M, 542M folding roller drive motor, 542 2nd folding roller, 543 heater, 543A heater controller, 544 temperature sensor, 545 distance sensor, 551 flat stitch stapler unit, 551A motor driver, 551M flat stitch stapler moving motor, 552 saddle stapler unit, 552A saddle stapler drive circuit, 552M drive motor, 553A motor driver, 553M sheet alignment first motor, 554A motor driver, 554M sheet alignment second motor, 580 discharge tray 590 Booklet tray, 590M Booklet tray lifting motor, L1, L2 communication line, n1 nip, R gap Part, S sheet.

Claims (5)

A sheet folding device that creases a sheet,
A folding blade for folding the sheet;
A first folding roller and a second folding roller that sandwich the sheet folded by the folding blade; and a heating device that heats the first folding roller;
An inter-roller distance measuring device for measuring a distance between the first folding roller and the second folding roller;
A temperature control device for controlling the temperature of the heating device based on information obtained from the inter-roller distance measuring device,
The temperature control device includes:
The distance measurement between the rollers when the sheet is pushed between the first folding roller and the second folding roller by the folding blade before the rotation by the first folding roller and the second folding roller. Measured by the inter-roller distance measuring device when a predetermined time has elapsed after the first distance between the rollers measured by the device and the heating of the first folding roller by the heating device was started. A sheet folding device that determines a heating condition for the heating device based on a difference from the second distance between the rollers. The temperature control device includes:
2. The heating condition is determined by correcting an initial heating condition determined in advance according to the sheet condition based on information obtained from a difference between the first distance between the rollers and the second distance between the rollers. The sheet folding apparatus according to claim 1. The temperature control device includes:
After the heating of the first folding roller by the heating device is started, the third distance between the rollers is measured by the inter-roller distance measuring device in the middle of a predetermined time.
The sheet folding apparatus according to claim 1 or 2, wherein the heating condition is further corrected based on a difference between the first distance between the rollers and the third distance between the rollers. The temperature control device includes:
As the heating condition, when the second distance between the rollers is larger than a predetermined comparison distance, the heating temperature by the heating device is set lower than the normal heating temperature, and the heating device The sheet folding apparatus according to any one of claims 1 to 3, wherein the heating time is set longer than a normal heating time.   The sheet folding device according to claim 4, wherein the timing for setting the heating time by the heating device to be longer than the normal heating time is after the normal heating time has elapsed.

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