JP4957714B2 - Paper post-processing device - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that accepts a sheet discharged from an image forming apparatus such as a copying machine, a printer, or a facsimile and performs at least a sheet folding process.

  For image-formed sheets ejected from the image forming apparatus, alignment processing for orderly arranging a predetermined number of sheets, stapling processing for binding the edge or center of the paper, and forming a fold at a predetermined position of the paper to form a booklet Various paper post-processing devices that perform half-folding processing are conventionally provided.

  As such a sheet post-processing apparatus, for example, a part for temporarily storing sheets discharged from the image forming apparatus, aligning the sheet end surfaces in the width direction and the length direction, and binding the sheet bundle with a stapler, and more An apparatus has been proposed in which a fold is formed in a bundle of sheets, and a portion that is folded and discharged is provided downstream of the sheet conveyance direction (for example, Patent Document 1).

Various techniques for correcting the curl of the paper have also been proposed in order to smoothly post-process the paper discharged from the image forming apparatus. For example, a curl correction roller is arranged downstream of the conveyance roller that sends the paper from the image forming apparatus to the post-processing apparatus, and the position of the correction roller with respect to the conveyance roller is changed to impart a deformation in the opposite direction to the curl to correct the curl. The technique which performs is proposed (for example, patent document 2 etc.). Also, the curl height of the stacked paper bundle is measured, and the operation of the roller that contacts the paper surface, the stopper that regulates the leading edge in the paper transport direction, the means that regulates the horizontal width direction of the paper, etc. is controlled, and the paper bundle is Techniques for aligning have also been proposed (for example, Patent Document 3).
JP2002-348034 JP2007-137552 JP2008-265959

  The proposed paper post-processing apparatus requires a large number of parts, which increases the size of the apparatus and requires a large installation space.

  In response to market demands for downsizing of the paper post-processing device, the processing tray for temporarily storing and aligning and stapling paper, and the processing tray for half-folding the paper, which had been provided separately, have been shared. Currently, the miniaturization of the device is being studied and developed.

  However, if the processing trays for the staple processing and the paper folding process are shared, the conventional cover member cannot be provided to prevent the paper from being caught by the pair of folding rollers for folding the paper, and the curled paper or the like is not provided. There is a risk that the paper will be caught in the processing tray due to being caught by the pair of folding rollers.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a curled sheet in a sheet post-processing apparatus that performs a sheet folding process without causing an increase in the size of the apparatus. It is to be able to fit smoothly into the processing tray without being caught.

The paper post-processing apparatus of the present invention that achieves the above object is a processing tray that receives and temporarily stores paper discharged from the image forming apparatus, and a paper that is provided in the vicinity of the processing tray and that is stored in the processing tray. A pair of center folding rollers for folding at the center in the sheet conveying direction and a control unit for controlling the driving of the pair of center folding rollers are provided. Stapling means is further provided in the vicinity of the processing tray, and is stored in the processing tray. Paper moving means for moving the received paper in the same direction and in the opposite direction to the paper transport direction, and by moving the paper by the paper moving means, stapling processing and half-folding processing of the paper stored in the processing tray are performed. a sheet post-processing apparatus which performs, in receiving the sheet to the processing tray, continuously or intermittently so driven roller pairs fold in the, and, the Wherein the rotating to repeat the folding roller pair and a normal rotation and a reverse rotation alternately.

Here, from the viewpoint of preventing the sheet from being caught in the pair of folding rollers, the amount of reverse rotation of the pair of folding rollers is larger than the amount of rotation of the forward rotation while receiving the sheet in the processing tray. It is preferable to rotate .

  In the paper post-processing apparatus of the present invention, even if the curled paper is temporarily caught by the pair of folding rollers while being stored in the processing tray, the pair of folding rollers is continuously or intermittently rotated to catch the paper. The paper is smoothly stored in the processing tray.

In the paper post-processing apparatus of the present invention , while receiving paper in the processing tray, the half-folding roller pair is driven continuously or intermittently, and the half-folding roller pair is alternately rotated forward and reverse. Thus, the sheet caught by the pair of folding rollers is shaken, and the catch of the sheet is released more quickly.

Further, in the sheet post-processing apparatus of the present invention, a sheet moving unit that further includes a stapling unit adjacent to the processing tray and moves the sheet stored in the processing tray in the same direction and in the opposite direction to the sheet conveying direction. By moving the sheet by the sheet moving means, stapling processing and half-folding processing of the paper stored in the processing tray are performed, so that the apparatus can be further downsized.

  Hereinafter, the sheet post-processing apparatus according to the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to these examples.

  First, an example of an image forming apparatus will be described with reference to FIG. The image forming apparatus of FIG. 1 is an apparatus having functions such as copy, scanner, fax, and network printing, and mainly includes a printing apparatus 1, a conveyance unit 2 that conveys paper to a post-processing apparatus, and a document reading apparatus 3. Has been. On the upper surface, a user interface device 42 for receiving user operations is installed.

  The printing apparatus 1 has an intermediate transfer belt 6 wound around a transfer belt driving roller 7 and a transfer belt driven roller 8 at the center thereof. Further, a secondary transfer roller 19 is installed in pressure contact with the outer peripheral surface of the intermediate transfer belt 6 at a position facing the transfer belt driving roller 7. This pressure contact portion becomes a secondary transfer nip portion.

  Below the intermediate transfer belt 6, a yellow process unit 9y, a magenta process unit 9m, a cyan process unit 9c, and a black process unit 9k are installed. A photoconductor 10y is installed in contact with the outer peripheral surface of the intermediate transfer belt 6 in the upper center of the yellow process unit 9y, and a charger 11y, an exposure device 12y, a developing device 13y, and a cleaner 14y are provided around the photoconductor 10y. is set up.

  A yellow primary transfer roller 15 y is disposed in contact with the inner peripheral surface of the intermediate transfer belt 6 at a position facing the photoconductor 10 y via the intermediate transfer belt 6. Above the intermediate transfer belt 6, a yellow toner cartridge 16 y that stores yellow toner to be supplied to the developing device 13 y is installed.

  Other than yellow, the process units 9m, 9c, 9k, the primary transfer rollers 15m, 15c, 15k, and the toner cartridges 16m, 16c, 16k have the same configuration as that of yellow.

  A paper feed tray 17 is installed below the process units 9y, 9m, 9c, and 9k, and stores recording paper PP0. In addition, a pair of paper feed rollers 18 for pulling out the recording paper PP0 is installed on the upper stage of the paper feed tray 17. In addition, a conveyance path 20a for conveying the recording paper PP0 is formed from the paper feed roller pair 18 to the conveyance unit 2 that conveys the sheet to the sheet post-processing device 43 via the secondary transfer nip portion. In addition, a conveyance roller pair 24a is installed in the conveyance path 20a. A timing roller pair 23 for controlling the conveyance timing of the recording paper PP0 is installed in the conveyance path 20a between the conveyance roller pair 24a and the secondary transfer nip.

  A fixing device 21 is installed on the downstream side of the secondary transfer nip portion in the paper conveyance direction, and a conveyance roller pair 24f for conveying the recording paper PP0 toward the conveyance unit 2 is installed on the downstream side of the fixing device 21. ing. In the fixing device 21, a pressure roller 22b is installed in pressure contact with the fixing roller 22a. A pressure contact portion between the fixing roller 22a and the pressure roller 22b becomes a fixing nip portion.

  A recording paper reverse conveyance path 20b is formed from the downstream side of the fixing device 21 toward the timing roller pair 23 for feeding again the recording paper PP0 on which the front surface image is fixed to the timing roller pair 23 during the duplex printing operation. A pair of transport rollers 24b, 24c, 24d, and 24e are installed along the recording paper reversal transport path 20b.

  Next, the transport unit 2 that transports the printed paper to the paper post-processing device 43 is provided on the downstream side of the transport roller pair 24f, and transports the paper by a plurality of roller groups. Of course, when there is no need to stack a plurality of types of sheets and combine them into a single unit document, it is possible to store the document in this part. It is also possible to provide a punch unit for making a hole for each sheet, or a folding unit for making a crease for each sheet.

  The configuration of the document reading device 3 will be described below. The document reading device 3 includes an automatic document transport device (hereinafter referred to as ADF) 4 that transports documents one by one to the image reading position RP, and a document transported by the ADF 4 or a document placed on the platen glass 38 by a user. And an image reading device 5 for reading an image.

  First, the configuration of the ADF 4 will be described below. On the upper surface of the ADF 4, a document tray 25 for loading a document PP1 before reading is installed, and at the lower stage, a discharge for loading the document PP1 after reading is loaded. A tray 33 is installed.

  A pickup roller 26 for pulling in the uppermost document PP1 of one or a plurality of documents PP1 stacked on the document tray 25 is installed above the document tray 25. Even when a plurality of documents PP1 are drawn by the pickup roller 26, the separation roller 27 and the separation roller 28 face each other in order to reliably supply one document PP1 to the image reading position RP. is set up.

  A pair of registration rollers 29 is provided for temporarily stopping the original PP1 supplied by the separation roller 27 and supplying the original PP1 to the image reading position RP, and correcting the skew of the original PP1. A document conveyance path 31 is formed from the registration roller pair 29 toward the discharge tray 33, and conveyance roller pairs 32 a, 32 b, and 32 c are installed along the document conveyance path 31. Further, a platen roller 30 is installed facing the slit glass 39 installed at the image reading position RP.

  Next, the configuration of the image reading device 5 will be described below. On the upper surface of the image reading device 5, a platen glass 38 for placing the document PP1 manually placed by the user and a vertically long slit glass 39 for flowing and reading the document PP1 automatically conveyed by the ADF 4 are installed. Has been.

  In addition, a light source 34 that illuminates the image reading position RP, mirrors 35a, 35b5, and 35c for guiding reflected light from the original PP1 to the imaging lens 36, and a CCD 37 as an image sensor are installed. The light source 34 and the mirror 35a are installed in the lamp unit 40, and the mirrors 35b and 35c are installed in the reflection mirror unit 41.

  The user I / F device 42 is provided on the upper surface or the front surface of the device, and sets various conditions required by the user and instructs the device to start and stop the operation. For this reason, input a start key for instructing operation start, a stop key for instructing operation stop, a reset key for initializing operation settings, a function selection key for selecting a function, a numerical value, etc. Hard key such as numeric keypad for clearing, clear key for clearing the entered numerical value, voice guidance key for changing the operating state of the voice guidance function, voice input key for changing the operating state of the voice input function, It comprises an LCD (liquid crystal display screen) for displaying various information, a speaker for outputting voice guidance, a microphone for receiving voice input, and the like. Further, for example, a resistance conversion type touch panel is attached to the surface of the LCD.

  The operation of the image forming apparatus will be described below with reference to FIG. When the copy key among the function keys of the user I / F device 42 is pressed, the device enters the copy mode. When a plurality of documents PP1 are stacked on the document tray 25 of the ADF 4 and the start key is pressed, the reading process of the document PP1 is started.

  The uppermost document PP1 of the plurality of documents PP1 is supplied to the document conveyance path 31 by the pickup roller 26, the separation roller 27, and the separation roller 28, and the skew correction and the supply timing adjustment are performed by the registration roller pair 29. After that, it is guided to the image reading position RP by the conveying roller pair 32a. Then, when passing through the image reading position RP, it is illuminated by the light source 34 and the reflected light is imaged on the CCD 37 to read the image of the original PP1. The document PP1 that has been read is discharged to the discharge tray 33 by the pair of conveying rollers 32b and 32c. The above-described processing is repeated until the original PP1 loaded on the original tray 25 runs out.

  The image read by the document reader 3 is formed on the recording paper PP0 as described below, and then post-processing is performed on the recording paper PP0.

  In the process units 9y, 9m, 9c, and 9k, yellow, magenta, cyan, and black toner images are formed and are primarily transferred onto the intermediate transfer belt 6 in a superimposed manner.

  On the other hand, the recording paper PP0 stored in the paper feed tray 17 is pulled out by the paper feed roller pair 18, transported along the transport path 20a, temporarily stopped by the timing roller pair 23, and then on the intermediate transfer belt 6. The toner is supplied to the secondary transfer nip portion at a timing synchronized with the toner image.

  After the toner image on the intermediate transfer belt 6 is transferred to the recording paper PP0 at the secondary transfer nip portion, the recording paper PP0 is supplied to the fixing nip portion inside the fixing device 21, and the recording paper PP0 and the toner image are heated. By being pressurized, the toner image is fixed on the recording paper PP0, and the recording paper PP0 is supplied to the transport unit 2 that transports the recording paper PP0 to the post-processing apparatus.

  In the transport unit 2, the paper on which the image is formed is transported to the paper post-processing device 43, but a paper storage unit can be provided in this portion. In that case, if a punch unit or a folding unit is built in, punch processing is performed by the punch unit according to the setting, and after the processing for making a crease is performed by the folding unit, the paper is stored from this portion. Can be taken out directly.

  FIG. 2 is a control block diagram illustrating an example of controlling the entire image forming apparatus and post-processing apparatus. The overall control unit 200 includes a document conveyance control unit 201, an image reading control unit 202, a print control unit 203, a post-processing control unit 204, a user I / F control unit 205, a ROM 206, a RAM 207, an image data storage unit 208, and an external device I. / F209. The overall control unit 200, the document conveyance control unit 201, the image reading control unit 202, the print control unit 203, the post-processing control unit 204, and the user I / F control unit 205 are all CPUs.

  The external device I / F 209 is connected to a network 210, and an external device such as a personal computer (hereinafter referred to as a PC) 211 is connected to the network 210.

  The overall control unit 100 reads a program from the ROM 206 and operates using the RAM 207 as a work area. The document transport control unit 201, the image reading control unit 202, the print control unit 203, the post-processing control unit 204, and the user I / F control unit 205. The entire system is controlled by controlling the image data storage unit 208 and the external device I / F 209.

  The document conveyance control unit 201 controls the ADF 4, the image reading control unit 202 controls the image reading device 5, and the print control unit 203 controls the printing device 1.

  The post-processing control unit 204 performs paper conveyance control for conveying the paper to the paper post-processing device 43. Further, when storing paper in the transport unit 2, the paper storage control unit operates a paper arranging unit (not shown) to align a plurality of papers in an orderly manner. Further, when a punch unit or a folding unit is provided, each operation is controlled.

  Next, an embodiment of the sheet post-processing device 43 that is the subject of the present invention will be described. FIG. 3 is a cross-sectional configuration diagram illustrating an installation position relationship between the printing apparatus 1 and the conveyance unit 2 of the image forming system and main components. This sheet post-processing apparatus is provided with three trays 46, 49, 72 for discharging sheets subjected to predetermined processing.

  The paper received from the transport unit 2 is appropriately distributed to the transport path 44 and the transport path 45 by a transport unit and a handing unit (not shown) according to a user instruction. The sheet guided to the conveyance path 44 is discharged to the first tray 46. The paper guided to the transport path 45 is sorted again into the transport path 47 and the transport path 48 by the transport means and the unrolling means (not shown), and the paper that has advanced to the transport path 47 is discharged to the second tray 49. The On the other hand, the sheet guided to the conveyance path 48 is sent to a booklet processing unit (hereinafter referred to as a saddle unit) 50, and a group of sheets are bound and aligned and then folded into a booklet. It is discharged to the booklet tray 72.

  Here, in the middle of the transport path 44 and the transport path 47, a punch unit for making punch holes in the paper and a stapler for arranging the paper in order and binding the paper bundle for each predetermined unit are arranged as necessary. Is done. In addition, full detection sensors 51 and 52 for detecting the limit of the amount of paper discharged are arranged in each tray. When the amount of paper discharged to the tray exceeds a predetermined amount, the user is notified and the apparatus is temporarily stopped. Is called. The second tray 49 is provided with an elevator function for moving the position downward in preparation for a large amount of discharged sheet bundles, and an upper surface detection sensor 53 for detecting the limit of tray movement. And a lower surface detection sensor 54 are provided to control the elevator function.

  Next, the configuration of the saddle unit 50 will be described with reference to FIGS. 3 and 4. The saddle unit 50 is provided with a saddle processing tray (processing tray) 55 for receiving the conveyed paper, which is inclined with the carry-in entrance upward, and regulates the leading end position of the conveyed paper. A leading end stopper (paper moving means) 56 capable of moving the position along the saddle processing tray 55 is disposed. The tip stopper 56 is moved by a conventionally known moving means such as a motor or a belt. The saddle processing tray 55 and the leading end stopper 56 constitute a paper storage means 57 that receives and temporarily stores paper.

  A saddle tray carry-in sensor 58 and a saddle carry-in roller pair 59 are disposed upstream of the saddle processing tray 55. When the saddle tray carry-in sensor 58 detects that the paper has been conveyed, the saddle carry-in roller pair 59 rotates to guide the paper into the saddle processing tray 55. Further, in order to guide the sheet to the receiving surface of the saddle processing tray 55, a saddle paddle 60a and a saddle paddle 60b having flexible guide rotating blades are provided on the upstream side and the downstream side, respectively. The saddle carry-in sensor 58, the saddle carry-in roller pair 59, and the saddle paddles 60a and 60b are for taking in paper and constitute the paper carry-in means 61. It should be noted that the present invention is not limited to the means described here, and it is conceivable to use a guide plate, an auxiliary roller, or the like that receives paper and guides it appropriately to the paper storage means 57. Incidentally, 62 shown in FIGS. 3 and 4 indicates a carry-in route.

  Facing one surface of the saddle processing tray 55, a pair of middle folding rollers 63 for folding the paper is disposed, and a folding knife 64 is disposed on the other surface facing it. The pair of folding rollers 63 and the folding knife 64 are for folding the sheet bundle stored in the saddle processing tray 55 at the center in the sheet conveying direction. A half-folding means 66 is configured together with a saddle discharge sensor 65 that detects discharge. The middle folding process will be described later.

  A saddle staple 67 for binding a bundle of sheets stored in the saddle processing tray 55 is disposed on the upstream side of the saddle processing tray 55 from the position where the pair of folding rollers 63 is disposed. A bundle of sheets that are stored in the saddle processing tray 55 and are aligned and aligned are bound by the saddle staple 67. The saddle staple 67 is arranged in the width direction of the paper, and 67a and 67b are arranged on the back side of the paper surface in the figure, and 67c and 67d are arranged on the front side of the paper surface in the figure, and each sandwiches the paper bundle. Bind. The binding position in the width direction of the paper (position in the depth direction of the paper surface in the figure) can be changed by the paper size or user designation.

  Next, saddle alignment plates 68a, 68b, 68c, and 68d for aligning the width direction of the paper (the depth direction of the paper surface in the figure) are installed on the upstream side and the downstream side of the side staple 67 in the paper conveyance direction. . Here, as viewed from the paper carry-in direction, 68a aligns the lower end surface on the right side (back side) of the paper, and 68b aligns the upper end surface of the paper on the right side of the paper. Similarly, 68c aligns the lower end face on the left side (front side) of the sheet, and 68d aligns the upper end face on the left side of the sheet.

  As sensors for detecting these operating conditions, a tip stopper limit sensor 69 that detects the limit position of the tip stopper 56, a folding knife home sensor 70 that detects that the center folding knife 64 has advanced to a predetermined position, and saddle processing. Saddle processing tray paper detection sensors 71 for detecting that a bundle of sheets is stored in the tray 55 are disposed.

  Note that the sheet bundle formed into a booklet by the center folding means 66 is discharged to the booklet tray 72 in FIG. Here, the limit of the discharge amount is detected by the booklet tray full detection sensor 73. When it is detected that the limit amount has been reached, the user is notified and the apparatus is temporarily stopped as in the case of the tray full detection sensor.

  Now, processing performed by the saddle unit 50 will be described below with reference to FIGS. First, when the sheet guided from the conveyance path 48 is detected by the saddle tray carry-in sensor 58, the saddle carry-in roller 59 rotates and receives the sheet in the saddle processing tray 55. When the loading of one sheet is detected, the pair of saddle paddles 60a and 60b arranged on the upper surface side of the saddle processing tray 55 rotate to guide the sheet to the tray side. Then, after the saddle tray carry-in sensor 58 confirms the passage of the paper, the saddle alignment plates 68a, 68b, 68c, and 68d arranged in the paper width direction of the carry-in path 62 after a predetermined time are arranged to open and close. Operate to place the paper in place. When the subsequent sheet is detected, the saddle alignment plates 68a, 68b, 68c, and 68d perform the same operation again, and this operation is repeated until the set number of sheets is completed. The saddle paddles 60a and 60b continue to rotate until the set number of sheets is completed.

  The sheet fed by the saddle carry-in roller 59 is stopped by a leading end stopper 56 disposed at the leading end of the saddle processing tray 55 in the sheet traveling direction. The same applies to subsequent sheets. In this way, a bundle of sheets of a predetermined number is temporarily stored in the saddle processing tray 55, and the vertical and horizontal positions are adjusted.

  When a predetermined number of sheets are prepared, the opening of the front end stopper 56 is displaced from the position indicated by the dotted line to the position indicated by the solid line by a driving means (not shown) such as a solenoid as shown in FIG. Pinch.

  Next, the operation of folding the sheet bundle 74 sandwiched between the leading end stoppers 56 with the leading ends aligned by the saddle staple 67 and then folding the folded paper by the folding means 66 will be described with reference to FIGS. Note that the front end stopper 56 moves along the saddle processing tray 55, but is simply indicated by a thick solid line in FIG.

  FIG. 6A is a state diagram when a sheet is received in the saddle processing tray 55. The leading edge stopper 56 moves and stops at the position B1, and the leading edge of the sheet is aligned at the position B1. The rear end of the sheet is at position A. The stop position of the leading end stopper 56 changes depending on the paper size. For example, in the case of a large paper, it moves and stops at the position B2. Note that a position X indicates a position where the saddle staple 67 binds the sheet bundle 74, and a position Y indicates a position where the pair of folding rollers 63 folds the sheet bundle 74.

  When the alignment in the width direction of the sheet is completed after receiving the sheet, the leading end stopper 56 moves along the saddle processing tray 55 with the sheet bundle 74 sandwiched downward, and the position C in FIG. Stop at. This position C is a position where the central portion in the sheet conveyance direction coincides with the needle striking position X of the saddle staple 67. At this position, the holding of the sheet by the leading end stopper 56 is released, and instead, saddle alignment plates 68a, 68b, 68c, 68d in the sheet width direction close the lateral end surface of the sheet bundle 74 to hold the sheet and drive staples. To staple the paper.

  Next, as shown in FIG. 6C, the leading end stopper 56 again sandwiches the sheet bundle 74 and moves downward to the position D again. This position D is a position where the central portion of the paper in the carrying direction, that is, the position where the staple is driven by the staple, and the position Y of the pair of folding rollers 63 and the folding knife 64 coincide. At this position, the holding of the sheet by the leading end stopper 56 is released.

  Subsequently, the folding process shown in FIG. 7 is performed. First, the front end stopper 56 releases the nipping of the sheet, and the folding knife 64 starts to protrude into the paddle processing tray 55 in the direction of the nip portion of the middle folding roller pair 63. An example of the moving means of the folding knife 64 is a crank mechanism. As shown in FIG. 7A, the folding knife 64 pushes the sheet bundle 74 into the nip portion of the middle folding roller pair 63 while making a crease at the center of the sheet conveyance direction.

  The pair of folding rollers 63 is urged in a direction in which they are pressed against each other by means not shown. As shown in FIG. 7B, when the sheet bundle 74 is pushed by the folding knife 64 to a position where the sheet bundle 74 is securely sandwiched by the pair of folding rollers 63, the folding knife home sensor 70 detects and the pair of folding rollers 63. Simultaneously rotates in the direction to sandwich the sheet bundle 74, and the folding knife 64 returns to the original position. At this time, the rotation direction of the middle folding roller pair 63 is assumed to be normal rotation.

  As a result, as shown in FIG. 7C, the sheet bundle 71 is folded at the center in the sheet conveyance direction to form a booklet, and is discharged to the booklet tray 72 by the pair of middle folding rollers 63. When the saddle discharge sensor 65 detects the discharge of the sheet bundle 71, the rotation of the half-fold roller pair 63 is stopped. On the other hand, when the folding process starts and the folding knife 64 returns to the initial position, the tip stopper 56 returns to the initial position after a predetermined time. That is, the folding knife 64 is in the position shown in FIG. 4, and the tip stopper 56 is in the position in FIG. This series of processing is repeated for each bundle of sheets designated by the user. In the embodiments so far, the binding position and the folding position are the central part in the sheet conveyance direction, but it is also possible to bind and bend the sheet at a position that is 1/3 of the sheet length. Further, the binding position and the folding position do not necessarily coincide with each other, and are appropriately set by the user.

  Here, the operation of the saddle alignment plates 68a, 68b, 68c, 68d will be described. As already described, these alignment plates align the positions in the width direction of the sheet, and are positioned upstream and downstream of the right and left in the sheet carry-in direction. These alignment plates are in a state where the width is widened when receiving the paper, and when the positions in the width direction of the paper are aligned, the alignment plates are closed to the paper width. The alignment plate may be opened and closed at the same time on the left and right, or with a time difference between the left and right. Also, the upper and lower sides of the paper may be opened and closed separately. Furthermore, the opening / closing operation may be performed a plurality of times for the reception of one sheet. The opening / closing operation of the alignment plate is appropriately set in consideration of the size, material, thickness, and the like of the paper.

  The rotation speed when the pair of folding rollers 63 folds the sheet bundle 74 may not be constant. For example, the rotation speed is initially reduced when the sheet bundle 74 is sandwiched, and then the rotation speed is increased. By controlling the rotational speed in this way, the folds of the sheet bundle can be clearly formed. The rotational speed of the pair of folding rollers 63 may be determined as appropriate depending on the paper size, paper quality, paper thickness, number of paper bundles, and the like. In order to clearly form the fold of the sheet bundle, it is also effective to temporarily stop the rotation of the middle folding roller pair 63 at a position where the fold portion is sandwiched.

  As described above, the saddle unit 50 has a function of storing sheets in an orderly manner for processing into a booklet shape, a function of binding a bundle of sheets, and a function of folding a bundle of sheets. As a result, the paper post-processing apparatus can be reduced in size. On the other hand, when all or curled paper is conveyed to the saddle processing tray 55, the paper may be caught by the half-folding roller pair 63 and may not fit in a predetermined position.

  Therefore, in the paper post-processing apparatus according to the present invention, when the curled paper is conveyed to the saddle processing tray 55, the paper is being folded into the saddle processing tray 55 so that the paper is not caught by the pair of folding rollers 63. The roller pair 63 is driven continuously or intermittently.

  FIG. 8 shows a state where the sheet is sent to the saddle processing tray 55 by the saddle carry-in roller 59 and stored. As shown in FIG. 8A, even when a sheet 75 with a curled tip is fed and hits a roller positioned upstream of the pair of folding rollers 63 in the sheet conveying direction, the sheet 75 is vibrated by the rotation of the roller. The given paper 75 is prevented from being caught by the roller.

  FIG. 6B shows the case where the leading end of the sheet 75 hits a roller located downstream of the pair of folding rollers 63 in the sheet conveying direction. In this case as well, the rotation of the roller causes the sheet 75 to rotate. Vibration is applied to prevent the sheet 75 from being caught by the roller. Therefore, as shown in FIG. 5C, even the curled paper 75 falls to a predetermined position on the saddle processing tray 55. Although the leading end of the sheet bundle 74 is in a curled state, the above-described leading end stopper 56 pinches the sheet bundle 74, so that it does not get caught during the subsequent movement, and the sheet is used for the subsequent stapling and folding processes. The effect of curl is not affected.

  FIG. 9 is a timing chart showing a series of operations from the reception of the sheet described above to the saddle processing tray 55 to the middle folding process. Sensors indicate the presence / absence of detection by ON and OFF, and operation parts such as the saddle alignment plate 66 and the saddle paddle 60 indicate the presence / absence or state of the operation.

  In FIG. 9, point A is the time when the first sheet is sent, and point B is the time when the last sheet is sent. The point C is a point in time when the aligned sheet bundle 74 starts to move downward with the leading end stopper 56 sandwiching it. The point D is when the sheet bundle 74 is bound by the saddle staple 67, that is, when the position C in FIG. 6B is reached. The point E is the point at which the front end stopper 56 grips the sheet bundle 74 again and starts moving downward. The point F is when the sheet is folded halfway by the pair of folding rollers 63, that is, when the point D in FIG. 6C is reached. The dot point is when the folding knife 64 starts to move, and the dot point is when the folded sheet bundle 74 is ejected in a booklet form and the folding is completed. Further, the re-point is the time when the leading end stopper 56 has returned to the initial position in preparation for the next sheet and has reached the B1 or B2 position in FIG.

  In FIG. 9, when the saddle carry-in sensor 58 is turned ON, the pair of folding rollers 63 rotates in the reverse direction. Accordingly, as described above, even the curled paper 75 is prevented from being caught by the pair of folding rollers 63. The reverse rotation of the half-folding roller pair 63 is continuously performed while a group of sheets are carried into the saddle processing tray 55, and stops when the last sheet is stored in the saddle processing tray 55. Next, when the sheet bundle 74 is folded in half, the pair of folding rollers 63 rotates forward. In more detail, it rotates at a low speed at an initial stage and then rotates at a high speed. When the booklet-like sheet bundle 74 is discharged, the half-folding roller pair 63 stops. Next, when the saddle carry-in sensor 58 is turned on, the half-folding roller pair 63 rotates in the reverse direction, and the above series of rotation control is repeated.

FIG. 10 shows another example of rotation control of the half-folding roller pair 63 when the sheet is received on the saddle processing tray 55. In the rotation control shown in FIG. 10, the half-folding roller pair 63 is controlled so as to repeat forward rotation and reverse rotation alternately and finely. As a result, the paper can be shaken by being vibrated, and a higher catching prevention effect can be obtained. Further , in order to prevent the curled sheet 75 from being caught in the pair of middle folding rollers 63 when the pair of middle folding rollers 63 is rotating forward, the amount of rotation with respect to one sheet is the amount of reverse rotation. to be greater than the amount.

  As described above, in order to realize the downsizing of the entire apparatus, special parts are added as a practical problem in integrating the paper receiving, organizing alignment, binding function, and paper folding function. Can be realized without any problems.

1 is a cross-sectional view of a main part illustrating an example of an image forming apparatus. 3 is a control block diagram illustrating a control example of an image forming apparatus and a sheet post-processing apparatus. FIG. FIG. 3 is a cross-sectional configuration diagram illustrating an installation position relationship between a sheet post-processing apparatus and an image forming apparatus and main components. It is a structure sectional view of a booklet processing part (saddle unit). It is a figure explaining clamping of the paper by a front-end | tip stopper. It is a figure which shows each movement position of a front-end | tip stopper. It is a figure which shows operation | movement of the folding knife and middle folding roller in a middle folding process. FIG. 10 is a diagram illustrating a state when a curled sheet is carried into a saddle processing tray. 6 is a control timing chart of each member until a sheet is received and discharged from a saddle processing tray. It is a timing chart which shows the other example of control of a middle folding roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing apparatus of image forming system 2 Conveyance unit of image forming system 3 Document reading apparatus of image forming system 43 Paper post-processing apparatus 50 Booklet processing part (saddle unit)
55 Saddle processing tray (processing tray)
56 Tip stopper (paper moving means)
57 Paper storage means 58 Saddle carry-in sensor 59 Saddle carry-in roller 60 Saddle paddle 61 Paper carry-in means 62 Carry-in path 63 Middle folding roller pair 64 Folding knife 65 Saddle carry-out sensor 66 Paper folding means 204 Post-processing control unit

Claims (2)

A processing tray for receiving and temporarily storing the paper discharged from the image forming apparatus, a pair of intermediate folding rollers provided near the processing tray and configured to bend the paper stored in the processing tray at a central portion in the paper conveyance direction; A control unit for controlling the driving of the pair of folding rollers,
Providing further stapling means in the vicinity of the processing tray, and providing paper moving means for moving the paper stored in the processing tray in the same direction and in the opposite direction to the paper transport direction,
A paper post-processing device that performs stapling and half-folding of the paper stored in the processing tray by moving the paper by the paper moving means ;
While the sheet is received in the processing tray, the pair of folding rollers is driven continuously or intermittently, and the pair of folding rollers is rotated so as to alternately repeat forward rotation and reverse rotation. Paper post-processing device. 2. The sheet post-processing apparatus according to claim 1, wherein the sheet folding roller pair is rotated so that the reverse rotation amount is larger than the forward rotation amount while the sheet is received in the processing tray.