Sheet binding processing device, and image forming system including sheet binding processing device

Abstract

To provide a sheet binding processing device that enables a buffer operation even when it receives a subsequent sheet longer than a predetermined length while performing post-processing.SOLUTION: A sheet binding processing device includes control means that, when a binding processing unit continuously performs binding processing on a bundle of predetermined sheets longer than a predetermined length in a conveyance direction, controls a conveying unit, a buffer conveying unit, and an upper branch conveying unit, so as to feed sheets forming the subsequent sheet bundle from a conveyance path to an upper branched path, and subsequently, convey the sheets in a switchback direction from the upper branched path to a buffer path to buffer the sheets.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to a sheet binding processing apparatus capable of performing a binding process on an image-formed sheet, and an image forming system including the sheet binding processing apparatus.

Background Art

[0002] A sheet post-processing apparatus is known as an apparatus that is connected to a paper discharge port of an image forming apparatus, temporarily holds an image-formed sheet on a tray, performs post-processing, and then stores it in a storage stacker. As this post-processing, a process of accumulating sheets and binding a bundle of sheets is known.

[0003] Patent Document 1 describes a sheet stacking apparatus capable of preventing misalignment when aligning a plurality of sheets stacked on a stacking tray. Patent Document 2 discloses an apparatus that performs a switchback conveyance of a sheet and buffers it when a sheet of a subsequent bundle is conveyed during the post-processing of a preceding bundle in order to improve productivity when continuously performing a bundling process.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When continuously performing a bundling process, in the buffer operation as disclosed in Patent Document 2, there is a problem that the sheet cannot be buffered without being discharged onto the processing tray. For example, when a discharging roller is nipping a bundle being processed or discharged, a subsequent sheet longer than a predetermined length is blocked by the discharging roller and cannot be buffered.

[0006] An object of the present invention is to provide a sheet binding processing apparatus and an image forming system including the sheet binding processing apparatus that enable a buffer operation even when receiving a subsequent sheet longer than a predetermined length during post-processing.

Means for Solving the Problems

[0007] The sheet binding processing apparatus according to the present invention includes a conveyance path through which a sheet is conveyed from a conveyance inlet to a discharge outlet, a conveyance unit provided in the conveyance path for conveying the sheet, a processing tray for receiving the sheet conveyed through the conveyance path from above, a binding processing unit for performing a binding process of binding a bundle of sheets on the processing tray, a pair of discharge rollers for discharging the bundle of sheets on which the binding process has been performed by the binding processing unit, a buffer path that branches downward from the conveyance path and buffers a sheet constituting a subsequent sheet bundle when there is a sheet bundle preceding the processing tray, a buffer conveyance unit provided in the buffer path for conveying the sheet, an upper branch path that branches upward from the conveyance path, an upper branch conveyance unit provided in the upper branch path for conveying the sheet, and control means for controlling the conveyance unit, the buffer conveyance unit, and the upper branch conveyance unit so that when continuously performing a binding process on a bundle of predetermined sheets longer than a predetermined length in the conveyance direction by the binding processing unit, after sending a sheet constituting a subsequent sheet bundle from the conveyance path to the upper branch path, the sheet is conveyed in a switchback direction from the upper branch path to the buffer path and buffered.

Effects of the Invention

[0008] According to the present invention, even when there is a sheet on the processing tray, it is possible to buffer a subsequent sheet longer than a predetermined length.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are given the same reference numerals, and duplicate explanations are omitted.

[0011] [Image Forming Apparatus] The image forming apparatus A in the image forming system shown in FIG. 1 will be described. The illustrated image forming apparatus A shows an electrostatic printing mechanism and includes an image forming unit A1, a scanner unit A2, and a feeder unit A3. Installation legs 25 for installation on an installation surface (for example, a floor surface) are provided on the apparatus housing 1. Further, inside the apparatus housing 1, a paper feeding unit 2, an image forming unit 3, a paper discharging unit 4, and a data processing unit 5 are incorporated.

[0012] The paper feeding unit 2 is configured to include cassette mechanisms 2a to 2c for storing sheets of a plurality of sizes for image formation, and feeds out a sheet of the size designated by the main body control unit 90 to the paper feeding path 6. For this purpose, a plurality of cassettes 2a to 2c are detachably arranged in the apparatus housing 1, and each cassette incorporates a separating mechanism for separating the internal sheets one by one and a paper feeding mechanism for feeding out the sheets. In the paper feeding path 6, a conveying roller 7 for feeding the sheets supplied from the plurality of cassettes 2a to 2c to the downstream side is provided, and at the end of the path, a registration roller pair 8 for aligning the leading edges of the sheets is provided.

[0013] In addition, a large-capacity cassette 2d and a manual feed tray 2e are connected to the paper feeding path 6. The large-capacity cassette 2d is configured to include an option unit for storing sheets of a size that is consumed in large quantities, and the manual feed tray 2e is configured to be able to supply special sheets such as thick paper sheets, coated sheets, and film sheets for which separation and feeding are difficult.

[0014] The image forming unit 3 is shown as an example of an electrophotographic printing mechanism, and a photoreceptor 9 (drum, belt), a light emitter 10 that emits an optical beam to the photoreceptor 9, a developing device 11 (developer), and a cleaner (not shown) are arranged around the rotating photoreceptor. The illustrated one shows a monochrome printing mechanism. An electrostatic latent image is optically formed on the photosensitive drum 9 by the light emitter 10, and toner ink is attached to this latent image by the developing device 11. Then, in accordance with the timing of image formation on the photoreceptor 9, a sheet is sent from the paper feeding path 6 to the image forming unit 3, the image is transferred onto the sheet by the transfer charger 12, and is fixed by a fixing unit (roller) 13 arranged in the paper discharge path 14. In the paper discharge path 14, a paper discharge roller 15 and a paper discharge port 16 are arranged, and the sheet is conveyed to a sheet post-processing device B described later.

[0015] Scanner unit A2 includes a platen 17 for placing an image document, a carriage 18 that reciprocates along the platen 17, a light source mounted on the carriage 18, and a reduction optical system 20 (a combination of mirrors and lenses) that guides the reflected light from the document on the platen 17 to a photoelectric conversion unit 19. Illustration 21 is a second platen (traveling platen), and an image is read from the sheet sent from the feeder unit A3 by the carriage 18 and the reduction optical system 20. The photoelectric conversion unit 19 transfers the image data obtained by photoelectric conversion to the image forming unit 3.

[0016] Feeder unit A3 includes a paper feed tray 22, a paper feed path 23 that guides the sheet sent out from the paper feed tray to the traveling platen 21, and a paper discharge tray 24 that stores the document for which image reading has been performed on the platen.

[0017] The image forming apparatus A is not limited to the above mechanism, and printing mechanisms such as an offset printing mechanism, an inkjet printing mechanism, and an ink ribbon transfer printing mechanism (thermal transfer ribbon printing, sublimation type ribbon printing, etc.) can be adopted.

[0018] [Sheet Post-processing Device] The sheet post-processing device B is, for example, a device that post-processes the sheet discharged from the paper discharge port 16 of the image forming apparatus A, and includes (1) a function of stacking and storing the image-formed sheet (print-out mode), (2) a function of sorting and storing the image-formed sheet (jogging sorting mode), (3) a function of collating and binding the image-formed sheets after aligning them (binding process mode), and (4) a function of folding and finishing binding after aligning and binding the image-formed sheets (bookbinding process mode).

[0019] Note that in this embodiment, the sheet post-processing device B does not necessarily have all of the above functions, and is appropriately configured according to the device specifications (design specifications). In this embodiment, as an example, it is assumed that it has a function of folding and finishing binding after aligning and binding the image-formed sheets.

[0020] FIG. 2 shows the configuration of the sheet post-processing apparatus B, and FIG. 3 shows the configuration around the straight path 28. The sheet post-processing apparatus B post-processes the sheets carried in from the straight path inlet 26 connected to the paper discharge port 16 of the image forming apparatus A, and then stores them in storage units (the first stack tray 49, the second stack tray 61, and the third stack tray 71, which will be described later). In the illustrated apparatus, the sheets sent to the straight path 28 are transferred from the processing unit B1 including the binding unit 47 to the first stack tray 49 (hereinafter referred to as the "first tray") and the third stack tray 71 (hereinafter referred to as the "third tray"). Also, the sheets sent to the straight path 28 are transferred from the saddle unit B2 to the second stack tray 61 (hereinafter referred to as the "second tray"). Note that since the straight path 28 is formed in a substantially straight line, even thick paper can be conveyed.

[0021] The processing unit B1 is arranged at the path exit (straight path paper discharge port 35) of the straight path 28. After aligning and stacking the sequentially sent sheets and performing a binding process, the sheets are stored in the first tray 49. The saddle unit B2 is arranged at the path exit (saddle path paper discharge port) of the saddle path 32 branched from the straight path 28. It is a post-processing unit that aligns and stacks the sequentially sent sheets, performs a saddle stitch (or may not perform a saddle stitch), performs a folding process, and then stores the sheets in the second tray 61. Hereinafter, each configuration will be described in detail.

[0022] <Device housing> As shown in FIG. 2, the sheet post-processing apparatus B includes a device housing 27, a straight path 28 built inside the device housing and having a straight path inlet 26 and a straight path paper discharge port 35, a processing unit B1 and a saddle unit B2 that post-process the sheets sent from the straight path 28, and the first tray 49, the second tray 61, and the third tray 71 that store the sheets sent from each post-processing unit. The illustrated device housing 27 is arranged at substantially the same height dimension as the housing 1 of the image forming apparatus A located on the upstream side, and the paper discharge port 16 of the image forming apparatus A and the straight path inlet 26 of the sheet post-processing apparatus B are connected on the installation surface.

[0023] The housing 27 of the sheet post-processing apparatus is configured to include an apparatus frame 70. The apparatus frame 70 forms a framework of a box-type apparatus as shown in FIG. 6, for example, and includes a front-side side frame frame 70f located at the front in the state of FIG. 1, a rear-side side frame frame 70r located at the back, and a stay member (connecting and reinforcing member) that connects between both side frame frames. A straight path 28, a processing unit B1, a saddle unit B2, etc., which will be described later, are attached between the left and right side frame frames. The apparatus housing 27 is not limited to the illustrated shape and can be in a form suitable for design. Needless to say, the apparatus frame 70 is not limited to the connecting stay structure between the left and right side frames, and various frame structures such as a monocoque structure can be adopted.

[0024] <Sheet loading path> As shown in FIG. 3, the straight path 28 is configured as a substantially straight path that traverses the apparatus housing 27 in a substantially horizontal direction, and includes a straight path inlet 26 that is continuous with the paper discharge port (main body paper discharge port) 16 of the image forming apparatus A, and a straight path paper discharge port 35 that is located on the opposite side across the apparatus from this transfer inlet (straight path inlet 26). In the straight path 28, a conveying mechanism capable of conveying a sheet from the straight path inlet 26 toward the straight path paper discharge port 35 and also capable of conveying from the straight path paper discharge port 35 toward the straight path inlet 26 is provided. In order from the straight path inlet 26 side, an inlet roller 29, a first conveying roller 201, a second conveying roller 202, and a third conveying roller 203 are arranged. Also, at the straight path paper discharge port 35, a paper discharge roller 36 (including a sheet conveying mechanism such as a belt) is arranged as a conveying mechanism. Further, near the straight path inlet 26, an inlet sensor S1 for detecting the leading and trailing edges of the received sheet and a lateral registration detection sensor S0 (detection unit) for detecting the end face position (side edge) parallel to the sheet conveying direction are arranged. Also, near the straight path paper discharge port 35, a paper discharge sensor S2 for detecting the leading and trailing edges of the sheet is arranged. The sheet discharged from the straight path paper discharge port 35 is discharged to the first tray 49 via the first paper discharge path 31 connected to the straight path paper discharge port 35, or is guided to the processing unit B1. Also, a punch unit 100 for punching a punch hole in the sheet is arranged in the straight path 28.

[0025] <Layout of the sheet loading path> In the straight path 28, as shown in FIGS. 2 and 3, the "saddle path 32", "saddle buffer path P2", "processing unit buffer path P1", and "upper conveyance path 30" are arranged in this order from the straight path inlet 26 toward the straight path discharge port 35. At the branch portions with the respective paths described above, as conveyance switching mechanisms (branch mechanisms) for the conveyed sheets, a saddle path flapper 33b, a saddle buffer path flapper 33a, a processing unit buffer path flapper 200, and an upper conveyance path flapper 34 are arranged. In the present embodiment, the saddle buffer path P2 and the upper conveyance path 30 are configured as a retraction path for retracting the sheet. Further, as shown in FIG. 2, a saddle portion B2 is provided on one side across the straight path 28, and the saddle buffer path P2 and the upper conveyance path 30 are provided on the opposite side (the other side). Thereby, the conveyance efficiency of the sheet located in the retraction path to the saddle portion B2 can be further improved.

[0026] Among the respective paths described above, the saddle path 32, the saddle buffer path P2, and the processing unit buffer path P1 are configured as a switchback path for conveying the sheet in a direction opposite to the conveyance direction from the straight path inlet 26 to the straight path discharge port 35 and loading it into the respective paths described above. Further, the upper conveyance path 30 is configured to be loaded by conveying the sheet in the same direction as the conveyance direction from the straight path inlet 26 to the straight path discharge port 35.

[0027] <Path Branching Mechanism> The saddle path flapper 33b, saddle buffer path flapper 33a, and processing unit buffer path flapper 200, which are the above-described sheet branching mechanisms, are composed of flapper guides that are movable so as to be able to switch the conveyance path of the sheet carried in from the straight path inlet 26, and are connected to a drive mechanism (not shown) such as an electromagnetic solenoid or a mini motor. The above-described saddle path flapper 33b guides the sheet sent from the straight path inlet 26 to the saddle path 32. The saddle buffer flapper 33a guides the sheet sent from the straight path inlet 26 to the saddle buffer path P2. The processing unit buffer flapper 200 guides the sheet sent from the straight path inlet 26 to the processing unit buffer path P1 via the processing unit buffer rollers 301a and 301b. The upper conveyance path flapper 34 includes a flapper guide that is movable so as to switch the conveyance path so as to convey the sheet sent from the straight path inlet 26 to either the straight path discharge port 35 or the upper conveyance path 30, and is connected to a drive mechanism (not shown) such as an electromagnetic solenoid or a mini motor.

[0028] <Upper Conveyance Path> Connected to the straight path 28 is an upper conveyance path 30 (printout discharge path) that conveys sheets other than those discharged to the straight path discharge port 35. At the path branching portion, an upper conveyance path flapper 34 for guiding the sheet to the upper conveyance path 30 is provided. Further, the upper conveyance path 30 is provided with upper conveyance rollers 303 (303a, 303b) for guiding the sheet to the third tray 71. Due to these, the sheet guided to the upper conveyance path 30 is discharged from the upper conveyance path discharge port 40 to the third tray 71 (overflow tray). In this embodiment, the upper conveyance path 30 is also used as a sheet storage path.

[0029] <Saddle Path> The straight path 28 is connected to a saddle path 32 for carrying the sheet into the saddle section B2, and the path branching section is provided with a saddle path flapper 33b for guiding the sheet to the saddle path 32. The sheet guided from the saddle path 32 to the saddle section B2 via the saddle path discharge port is subjected to intermediate binding and folding processes, and then discharged to the second tray 61 via the substantially horizontal saddle discharge path 68.

[0030] <Saddle buffer path> The straight path 28 is connected to a saddle buffer path P2 for temporarily carrying and waiting the sheets to be subjected to intermediate binding and folding processes in the saddle section B2, and a saddle buffer path flapper 33a for guiding the sheet to the saddle buffer path P2 is configured. Further, the saddle buffer path P2 is provided with a conveying roller 302 (302a, 302b) for carrying the sheet and temporarily waiting.

[0031] A fourth tray discharge port 305 is provided on the downstream extension of the saddle buffer path P2. Therefore, the sheet carried into the saddle buffer path P2 can be discharged onto the fourth tray 310 and stacked. In this case, the fourth tray 310 is arranged vertically above the saddle buffer path P2. Note that the fourth tray 310 may be shared with the exterior parts on the top surface of the saddle post-processing device B, may be fixed to the device housing, or may be configured to be movable up and down in a substantially vertical direction with a drive mechanism.

[0032] In addition, by arranging the saddle buffer path P2 at a position overlapping vertically above the punch unit 100, the device can be made more compact. However, if space is required to bounce the punch unit 100 upward to remove the sheet staying in the punch unit 100, the saddle buffer path P2 may be arranged at a position not overlapping vertically above the punch unit 100.

[0033] <Conveying roller shift mechanism in the loading path> Here, the conveyance shift mechanism provided in the conveyance rollers on the above-described conveyance path will be described with reference to FIGS. 6 and 7. The first conveyance roller 201, the second conveyance roller 202, the third conveyance roller 203, and the conveyance rollers 302a and 302b are each configured to include a drive roller 111 and a driven roller 112 that are rotatably supported by bearings on the left and right side frame frames 70f and 70r. A drive rotation shaft is connected to the drive roller shaft 113 by a transmission mechanism 116 (the one shown in the figure is a gear transmission), and a drive motor (not shown) common to the paper discharge roller 36 is connected to the drive rotation shaft 115. Further, the driven roller shaft 114 is supported by bearings so as to be movable on the left and right side frame frames 70f and 70r.

[0034] Each of the above-described conveyance rollers is rotatably attached to a shift member 117 that connects the drive roller shaft 113 and the driven roller shaft 114. By the shift member 117, the drive roller shaft 113 and the driven roller shaft 114 are connected so as to move integrally in the axial direction (thrust direction) and are rotatable independently in the radial direction. The drive roller shaft 113 is supported by bearings on the left and right side frame frames 70f and 70r. The end of the drive roller shaft 113 is located within the range indicated by the axial movement region of the conveyance roller on the front side of the side frame frame 70f, and the other end is located on the rear side of the side frame frame 70r. The shift member 117 (for example, a block member made of synthetic resin) is supported by the drive roller shaft 113 and the driven roller shaft 114 and integrally connects both roller shafts.

[0035] A rack 117a is integrally formed on the shift member 117 and meshes with a shift motor M9 attached to the side frame frame 70r (apparatus frame; the same applies hereinafter) and a transmission pinion 117b. With such a configuration, it is possible to axially positionally move (shift move) the shift member 117 by the rotation of the shift motor M9 (the one shown in the figure is a stepper motor capable of forward and reverse rotation).

[0036] A driven gear 118 is integrally formed on the drive rotating shaft 115, and the rotation of the drive motor is transmitted to the driven gear 118. Further, a pair of conveying rollers (a drive roller and a driven roller) is pressed against the driven rotating shaft 119 so as to be driven to rotate by the rotation of the drive rotating shaft 115.

[0037] In the present embodiment, the drive rotating shaft 115 and the driven rotating shaft 119 are connected to each other and are configured such that one of them is driven to move axially and the other follows. Alternatively, one of the drive roller 111 and the driven roller 112 may be attached to the rotating shaft so as to be slidable (slidable) in the axial direction, and the other roller may be moved in the axial direction and configured to be interlocked with the movement.

[0038] <Conveying shift operation> Here, the shift operation (jog sorting mode) of the sheet carried into the sheet post-processing apparatus B will be described. The sheet fed from the image forming apparatus A is conveyed in the order of the straight path inlet 26, the inlet roller 29, the first conveying roller 201, the second conveying roller 202, and the third conveying roller 203. At this time, the delivery timing of the sheet is also detected by the inlet sensor S1 simultaneously. The sheet carried in by the inlet roller 29 has its end position detected by the lateral registration detection sensor S0 while passing through the straight path 28. The lateral registration detection sensor S0 detects how much lateral registration error X of the sheet has occurred with respect to the center (central) position.

[0039] When the lateral registration error X detected by the lateral registration detection sensor S0 is detected, a shift operation of the sheet (also referred to as "lateral registration detection process") is performed by moving a predetermined amount in the front and back directions while the rollers of the first conveying roller 201, the second conveying roller 202, and the third conveying roller 203 are sequentially conveyed. Thereafter, the sheet is diverted by the upper conveying path flapper 34 of the branching mechanism to the straight path discharge port 35 or the upper conveying path 30, and is conveyed and discharged onto the first tray 49 or the second tray 71.

[0040] <Processing unit> The processing unit B1 is a post-processing unit configured to include a processing tray 37 that is arranged on the downstream side of the straight path 28 and aligns and stacks the sheets sent from the straight path discharge port 35, and a binding processing mechanism that binds the stacked sheet bundle. As shown in FIG. 3, a step is formed at the straight path discharge port 35 of the straight path 28, and the processing tray 37 is arranged below the step. A first discharge path (first switchback path) 31 is formed between the straight path discharge port 35 and the processing tray 37 to reverse the conveyance direction from the discharge port and guide the sheet onto the tray.

[0041] A sheet carrying mechanism for carrying the sheet from the discharge port onto the tray is arranged between the straight path discharge port 35 and the processing tray 37. The processing tray 37 is provided with a positioning mechanism for positioning the sheet at a predetermined binding position and a sheet bundle discharging mechanism for discharging the bound sheet bundle to the downstream first tray 49. Each configuration will be described later.

[0042] Note that the processing tray 37 shown in FIG. 3 bridgely supports the sheets sent from the straight path discharge port 35 between the downstream first tray 49. That is, the sheets sent from the straight path discharge port 35 are configured to be bridged and supported such that the leading end thereof is on the uppermost sheet of the downstream first tray 49 and the trailing end thereof is on the processing tray 37.

[0043] <Saddle part> The saddle part B2 is a post-processing unit that aligns and stacks the sheets sent from the straight path 28, and performs binding processing on the central part and inner folding processing (hereinafter referred to as "magazine finishing"). A second tray 61 is arranged on the downstream side of the saddle part B2 to store the bound sheet bundle. Note that it may be configured to align and stack one or a plurality of sheets and perform only inner folding processing on the central part without performing middle binding processing.

[0044] The saddle part B2 is composed of a guide member 66 for stacking sheets in a bundle, a tip restricting stopper 67 for positioning the sheet at a predetermined position on the guide member 66, a stapling device 63 (center stapling unit) for stapling the central part of the sheet positioned by the tip restricting stopper 67, and a folding mechanism (folding roll pair 64 and folding blade 65) for folding the sheet bundle at the central part after the stapling process.

[0045] The center stapling unit 63 employs a mechanism that is generally known, in which the sheet bundle is sandwiched between a head unit and an anvil unit and moved along the central part (line) of the sheet for stapling. Also, as shown in Figure 2, the folding mechanism is configured such that the folding line of the sheet bundle is inserted into the mutually pressed folding roll pair 64 by the folding blade 65 and folded by the rolling of the roll pair.

[0046] The illustrated processing part B1 and the straight path 28 are arranged in a substantially horizontal direction, the saddle path 32 for guiding the sheet to the saddle part B2 is arranged in the vertical direction, and the guide member 66 for aligning and stacking the sheets is arranged in a substantially vertical direction. By arranging the straight path 28 in the direction crossing the device housing 27 and arranging the saddle path 32 and the saddle part B2 in the vertical direction, the device can be made slimmer.

[0047] A second tray 61 is arranged on the downstream side of the saddle part B2 and can store the sheet bundle folded in a magazine shape. The second tray 61 is arranged below the first tray 49. This is because it is assumed that the usage frequency of the first tray 49 is higher than that of the second tray 61, and the position of the first tray 49 is set at a height where it is easy to take out the sheets on the tray.

[0048] <Punch unit> The punch unit 100, which is arranged on the straight path 28 and punches punch holes in the sheet sent from the straight path inlet 26, will be described with reference to FIG. 5. The punch unit 100 arranges a plurality of punch members 101a to 101e at a predetermined interval in a direction orthogonal to the sheet conveyance direction of the straight path 28, and punches the selected number of holes in the sheet.

[0049] FIG. 4 shows the overall configuration of the punch unit 100. The punch unit 100 includes a unit frame 102, a plurality of punch members 101a to 101e arranged vertically movably on the unit frame 102, a drive cam that reciprocates each punch member vertically (reciprocates in the punching direction), and a drive motor M7 that drives this drive cam.

[0050] Reference numeral 104 in the figure is a waste box, which is arranged below the punch member 101 and stores the punched waste paper pieces. The waste box 104 is slidably attached to a guide rail (not shown) on the apparatus frame 70 (different from the unit frame). Reference numeral 106 in the figure is a rotary operation member, which forcibly rotates the drive cam when a jam occurs in the punch member 101 or an abnormality occurs in the drive motor M7, and separates (peels off) the punch member 101 that has bitten into the sheet. For this reason, the rotary operation member 106 is composed of a manual rotary knob connected to the rotary shaft 107 of the drive cam.

[0051] As shown in FIG. 5, the unit frame 102 includes an upper frame 102a having a predetermined length in a direction orthogonal to the sheet conveyance direction of the straight path 28, and a lower frame 102b. A plurality of punch members 101a to 101e are arranged at a predetermined interval in a direction orthogonal to the sheet conveyance direction (hereinafter referred to as "conveyance orthogonal direction") on the upper frame 102a so as to be reciprocally movable (vertically movable) in the punching direction. Punching holes (dies) are formed in the lower frame 102b at positions facing each punch part 101. Further, a drive rotary shaft 107 is arranged on the unit frame 102, and a drive cam for moving each punch member 101 up and down is attached to the drive rotary shaft 107. A drive motor M7 is connected to the drive rotary shaft 107 via a transmission mechanism.

[0052] The drive cam is composed of a cylindrical cam member axially attached to the drive rotation shaft 107 and corresponding to a plurality of punch members 101, and each punch member is connected to this cam member by a connecting pin. Then, by rotating the drive rotation shaft 107 by a predetermined angle, the punch member 101 moves up and down in the punching direction. At this time, the first group 101b, 101d (for example, two-hole punching) of the plurality of punch members move up and down in the punching direction at the first rotation angle of the drive rotation shaft 107, and the second group 101a, 101c, 101e (for example, three-hole punching) move up and down in the punching direction at a different second rotation angle.

[0053] Therefore, when the binding process control unit 95 described later reciprocally rotates the drive rotation shaft 107 within a preset angle range by controlling the motor M7, the punch members 101b, 101d of the first group can be made to perform a punching motion, and when reciprocally moved within a different angle range, the punch members 101a, 101c, 101e of the second group can be made to perform a punching motion.

[0054] The waste box 104 is disposed below the punch member 101, supported by a guide rail (not shown) provided on the apparatus frame, and is detachable from the front side of the apparatus.

[0055] Also, a drive motor M7 is connected to the drive rotation shaft 107 via a speed reduction mechanism (gear transmission mechanism), and a rotating member is passed through a hole provided in the side frame 70f so that an operator can manually rotate it, and it is disposed on the front side of the side frame 70f. And a front cover is disposed on the front side of the apparatus so as to be openable and closable, and the rotation operation member 106 can be operated in the open lid state. Note that when the cover is in the open lid state, the drive power is not supplied (cut off) to the drive motor M7.

[0056] [Configuration of the processing unit] Next, the configurations of the sheet loading mechanism, sheet positioning mechanism, binding processing mechanism, and sheet bundle unloading mechanism of the processing unit B1 will be described.

[0057] <Sheet Loading Mechanism> As shown in FIG. 3, between the straight path paper discharge port 35 and the processing tray 37, there are arranged a reverse transfer mechanism for switchback conveying the sheet from the straight path paper discharge port 35 in the paper discharge direction and the opposite direction of paper discharge, a guide mechanism (sheet guide member) 44 for guiding the sheet to the tray side, and a scraping rotating body 46 for guiding the sheet to the rear end regulating portion.

[0058] The reverse transfer mechanism includes a lifting roller 41 that moves up and down between an operating position where it engages with the sheet carried onto the processing tray 37 and a separated standby position, and a paddle rotating body 42 that transfers the sheet in the direction opposite to the paper discharge direction. The lifting roller 41 and the paddle rotating body 42 are attached to a swing bracket 43.

[0059] A swing bracket 43 is arranged on the apparatus frame 27 so as to be swingable about a rotation axis (for example, a paper discharge roller axis). The rotation axes of the lifting roller 41 and the paddle rotating body 42 are supported by bearings on the swing bracket 43. And a lifting motor (not shown) is connected to the swing bracket 43. The swing bracket 43 moves the mounted lifting roller 41 and paddle rotating body 42 up and down between an operating position where they engage with the sheet and a standby position where they are separated from the sheet.

[0060] Also, a drive motor (not shown) is connected to the lifting roller 41 and the paddle rotating body 42. The drive is transmitted such that the lifting roller 41 rotates in the forward and reverse directions and the paddle rotating body 42 rotates in the reverse direction (the direction opposite to the paper discharge direction). Further, a driven roller 48 that is in pressure contact with the lifting roller 41 is arranged on the processing tray 37, and a single sheet or a bundled sheet is nipped and discharged to the downstream side.

[0061] Between the lifting roller 41 and the scraping and rotating body 46 described later, a guide mechanism is arranged to guide the rear end of the sheet carried onto the processing tray 37 toward the sheet end regulating portion 38. The guide mechanism includes a sheet guide member 44 that moves up and down from the dotted line state to the solid line state in FIG. 3. When the sheet is discharged from the straight path discharge port 35, the sheet guide member 44 retracts to the dotted line position, and after the rear end of the sheet passes through the straight path discharge port 35, it guides the rear end of the sheet onto the processing tray 37. For this reason, a drive mechanism (not shown) is connected to the sheet guide member 44, and it moves up and down according to the timing of guiding the rear end of the sheet from the straight path discharge port 35 onto the processing tray 37.

[0062] <Sheet positioning mechanism> On the processing tray 37, positioning mechanisms 38 and 39 for positioning the sheet at a predetermined binding position are arranged. The illustrated ones include a sheet end regulating portion 38 that abuts and regulates the rear end of the sheet, and a side edge aligning portion 39 that positions the side edge of the sheet at a reference (center reference, one-sided side reference) position.

[0063] As shown in FIG. 3, the sheet end regulating portion 38 is composed of a stopper member that abuts and regulates the rear end of the sheet. Also, although the side edge aligning member 39 will be described later with reference to FIG. 9, when the sheet is discharged from the straight path 28 with the center as the reference, depending on the type of binding mode, positioning with the same center reference or positioning with one-sided side reference is executed.

[0064] <Side edge alignment mechanism> As shown in FIG. 9, the side edge alignment plates 39F and 39R project upward from the paper placement surface 37a of the processing tray 37 and have a regulating surface 39x that engages with the side edge of the sheet, and are arranged in a pair on the left and right so as to face each other. And this pair of side edge aligning portions 39 are arranged on the processing tray 37 so as to be reciprocally movable with a predetermined stroke. This stroke is set by the size difference between the maximum size sheet and the minimum size sheet and the offset amount for laterally shifting (offset conveyance) the aligned sheet bundle in either the left or right direction.

[0065] That is, the moving strokes of the left and right side edge alignment plates 39F and 39R are set by the moving amount for aligning sheets of different sizes and the offset amount of the sheet bundle after alignment. Note that the side edge alignment plates 39F and 39R are moved by a predetermined amount to the right for right corner stitching and to the left for left corner stitching of the sheet carried out based on the center reference during corner stitching (offset movement). This offset movement can be either executed one by one each time a sheet is carried into the processing tray 37 (for each carried-in sheet) or moved for each bundle in order to perform the stitching process after aligning the sheets in a bundle shape.

[0066] Therefore, as shown in FIG. 9, the side edge alignment unit 39 is configured to include a right side edge alignment member 39F (front side of the apparatus) and a left side edge alignment member 39R (rear side of the apparatus). On both side edge alignment members, a regulating surface 39x that engages with the side end of the sheet is supported on the processing tray 37 so as to move in the approaching or separating direction from each other. The processing tray 37 is provided with a slit groove (not shown) penetrating through the front and back, and the side edge alignment unit 39 having a regulating surface 39x that engages with the side edge of the sheet is slidably fitted to this slit groove.

[0067] Each of the side edge alignment plates 39F and 39R is slidably supported on the back side of the tray by a plurality of guide rollers 80 (which may be rail members), and a rack 81 is integrally formed. Alignment motors M1 and M2 are connected to the left and right racks 81 via pinions 82. The left and right alignment motors M1 and M2 are configured as stepping motors, and the positions of the left and right side edge alignment plates 39F and 39R are detected by a position sensor (not shown), and each alignment member is configured to be positionally movable in either the left or right direction by a specified moving amount based on the detected value. Note that the present invention is not limited to the illustrated rack and pinion mechanism, and each side edge alignment plate 39F and 39R may be fixed to a timing belt, and the timing belt may be connected to a motor that reciprocates left and right via pulleys.

[0068] With the above configuration, the binding process control unit 95, which will be described later, waits for the left and right side edge alignment members 39F and 39R at a predetermined standby position (sheet width size + α position) based on the sheet size information provided from the image forming apparatus A. Then, during "multi-binding", a sheet is carried into the processing tray 37, and the alignment operation is started at the timing when the sheet end hits the sheet end regulation unit 38. This alignment operation is performed by rotating the left and right alignment motors M1 and M2 by the same amount in opposite directions (approaching direction). Then, the sheet carried into the processing tray 37 is positioned based on the sheet center and stacked in a bundle. By repeating this sheet carrying operation and alignment operation, the sheets are partially aligned and accumulated in a bundle on the processing tray 37. At this time, sheets of different sizes are positioned based on the center reference. Also, during "corner binding", a sheet is carried into the processing tray 37, and the alignment operation is started at the timing when the sheet end hits the sheet end regulation unit 38. This alignment operation is performed by making the moving amounts of the alignment plate on the binding position side and the alignment plate on the opposite side of the binding position different. Then, the moving amount is set so that the sheet corner is positioned at a preset binding position.

[0069] <Binding processing mechanism> On the processing tray 37, a binding processing mechanism 47 for binding the sheet bundle accumulated on the paper placement surface 37a is arranged. The paper placement surface 37a on the processing tray 37 is positioned at a predetermined binding position by a positioning mechanism (sheet end regulation unit 38 and side edge alignment unit 39). The binding processing mechanism 47 is configured as a binding unit 47 (hereinafter the same as "staple unit") that stitches the sheet bundle with staple pins.

[0070] On the processing tray 37, a binding processing mechanism 47 for binding the rear end of the sheet carried in from the straight path discharge port 35 is arranged, and the binding processing mechanism 47 is composed of a staple unit 47 that can move along the rear end of the paper placement surface 37a of the processing tray 37 as shown in FIG. 8.

[0071] Figs. 8 and 9 show the staple unit 47 disposed on the processing tray 37. In Fig. 9, a stitching position Cp1 is set at the sheet corner located on the left side in the drawing. The staple unit 47 moves along the first running rail 53 and the second running rail 54 formed on the apparatus frame 27b with a predetermined stroke SL1.

[0072] Fig. 9 shows the sheet carried into the processing tray 37 and the moving stroke SL1 of the stitching unit 47. Sheets of different sizes from the maximum size sheet to the minimum size sheet are carried into the processing tray 37 with the center as a reference. A pair of left and right side edge alignment plates 39F and 39R align different-sized sheets so that the stitching side edges of the sheets (the one shown in the figure is the left side edge) coincide. For this purpose, the left and right side edge alignment plates 39F and 39R are respectively connected to different drive motors M1 and M2, and the stitching process control unit 95 described later sets the moving amounts of the left and right side edge alignment plates 39F and 39R according to the sheet size.

[0073] Note that the stitching process control unit 95 described later aligns the sheet with the center as a reference in stitching processes other than stitching the sheet corners, for example, in the multi-stitching mode described later. In this case, the left and right side edge alignment plates 39F and 39R position the sheet at the stitching position by moving the same amount closer to the sheet center from the standby position.

[0074] Referring to Fig. 9, the stitching unit 47 moves with a stroke SL1 between the standby position Wp1 (the first standby position) and the stitching position Cp1. That is, the staple unit 47 reciprocates between the standby position Wp1 and the stitching position Cp1 along the running rails 53 and 54 (such as guide grooves and guide rods). The first standby position Wp1 is set outside the maximum size sheet to be stitched on the processing tray 37.

[0075] FIG. 10 shows the configuration of the stapling unit 47. On the apparatus frame 27b, a pair of left and right pulleys 58a and 58b are arranged along the moving region (the left - right direction in FIG. 9) of the stapling unit 47, and a timing belt 59 (toothed belt) is stretched between both pulleys. A drive motor M3 (stepping motor) is connected to one of the pulleys 58a.

[0076] <Staple moving mechanism> As shown in FIG. 8, the stapling unit 47 is mounted on the apparatus frame (chassis frame) 27b which is fixed to the side frame frames 70f and 70r by passing through an opening provided in the side frame frame 70f of the apparatus frame 70 so as to be movable in a predetermined stroke. On the apparatus frame 27b, a first running rail 53 and a second running rail 54 are arranged. A running rail surface 53x is formed on the first running rail 53, and a running cam surface 54x is formed on the second running rail 54. The running rail surface 53x and the running cam surface 54x cooperate with each other to support the stapling unit 47 (hereinafter referred to as the "moving unit" in this section) so as to be reciprocally movable in a predetermined stroke, and at the same time control its angular posture.

[0077] The first running rail 53 and the second running rail 54 are formed with a rail surface 53x and a running cam surface 54x so as to reciprocate within the moving range of the moving unit. As shown in FIG. 10, a timing belt 59 connected to a drive motor (running motor) M3 is fixed to the stapling unit 47. The timing belt 59 is wound around a pair of pulleys 58a and 58b pivotally supported by the apparatus frame 27b, and a drive motor M3 is connected to one of the pulleys. Therefore, by the forward and reverse rotation of the drive motor M3, the stapling unit 47 reciprocates with a stroke SL1.

[0078] The staple unit 47 is engaged with the first and second traveling rails 53 and 54 as follows. As shown in FIG. 8, the staple unit 47 is provided with a first rolling roller 83 (rail fitting member) that engages with the traveling rail surface 53x and a second rolling roller 84 (cam follower member) that engages with the traveling cam surface 54x. Further, ball-shaped sliding rollers 47x (two places are shown in the figure) that engage with the support surface of the frame 27b are formed on the staple unit 47. Further, a guide roller 47y that engages with the bottom surface of the bottom frame portion frame is formed on the staple unit 47, preventing the staple unit 47 from floating from the apparatus frame 27b.

[0079] With the above configuration, the staple unit 47 is movably supported by the apparatus frame 27b with the sliding rollers 47x and the guide rollers 47y. Further, the first rolling roller 83 rotates along the traveling rail surface 53x, and the second rolling roller 84 rotates along the traveling cam surface 54x and travels along the rail surface 53x and the cam surface 54x while rotating.

[0080] <Stack Tray Lifting Mechanism> As shown in FIG. 11, the sheet post-processing apparatus B is provided with a first tray 49. The first tray 49 is configured to move up and down according to the loading amount of the sheets. For this reason, guide rollers 85 are provided at two positions, upper and lower, at the base end portion of the first tray 49, and the guide rollers 85 are fitted and supported by lifting guides 86 provided on the apparatus frame 27. And a lifting gear 88 is provided at the base end portion of the first tray 49 and is connected to a lifting rack gear 87. Further, a lifting motor M4 is connected to the lifting gear 88. Therefore, by controlling the rotation of the lifting motor M4, the first tray 49 moves up and down according to the loading amount of the sheets.

[0081] <Sheet Bundle Unloading Mechanism> On the processing tray 37, a sheet bundle discharging mechanism for discharging the stapled sheet bundle toward the downstream first tray 49 is arranged. As a configuration for conveying the sheet bundle downstream, a method of conveying with a pair of rollers that are in pressure contact with each other (discharging roller mechanism), and a conveyor mechanism that pushes out the rear end of the sheet with a pushing member that moves along the tray surface from the upstream side to the downstream side are known. The illustrated apparatus employs both of them.

[0082] FIG. 12 shows the sheet bundle discharging mechanism. The conveyor mechanism is configured to include an extrusion protrusion 45 that transfers from the stapling position (processing position) located upstream along the processing tray 37 to the downstream stack tray (first tray) 49, a conveyor belt 45v that moves the extrusion protrusion, and a drive motor M6. On the processing tray 37, a driven roller 48 is arranged at its discharge port (the boundary between the paper placement surface 37a and the first tray 49), and a lifting roller 41 that is in pressure contact with the driven roller 48 is arranged opposite thereto, and the driven roller 48 and the lifting roller 41 constitute a discharging roller mechanism.

[0083] Therefore, on the processing tray 37, a conveyor mechanism 45, 45v that transfers the sheet bundle so as to push it out from the upstream side to the downstream side, and a discharging roller mechanism 48, 41 that nips and discharges the sheet bundle are arranged. FIG. 12(a) shows a state where the sheet bundle is located at the stapling position on the processing tray 37. At this time, the conveyor mechanism 45, 45v and the discharging roller mechanism 48, 41 are in an operating state. FIG. 12(b) shows a state during the transfer of the sheet bundle from the processing position to the downstream side, and the sheet bundle is sent downstream by the movement of the extrusion protrusion 45 and the rotation of the discharging roller mechanism 48, 41. FIG. 12(c) shows a state immediately before discharging the sheet bundle to the downstream first tray 49, and on the processing tray, the sheet bundle is gradually (slowly) sent downstream by the rotation of the discharging roller mechanism 48, 41. At this time, the extrusion protrusion 45 waits at the illustrated position and returns (moves backward) to the initial position.

[0084] <Configuration of Staple Unit> Regarding the above staple unit, its configuration will be described with reference to FIG. 13. The staple unit 47 is unitarily configured separately from the sheet post-processing device B. A box-shaped unit frame 47a, a drive cam 47d pivotally supported on the unit frame 47a, and a drive motor M4 for rotating the drive cam 47d are mounted on the unit frame 47a.

[0085] A staple head 47b and an anvil member 47c are arranged opposite to each other at the stapling position on the drive cam 47d. The staple head 47b is biased from an upper standby position to a lower staple position (anvil member) by a biasing spring (not shown) on the drive cam 47d and moves up and down. A needle cartridge 52 is detachably mounted on the unit frame 47a.

[0086] The needle cartridge 52 stores linear blank needles, and a needle feeding mechanism supplies the needles to the staple head 47b. The staple head portion 47b incorporates a former member for bending a linear needle into a U-shape inside and a driver for pressing the bent needle into the sheet bundle. With such a configuration, the drive motor M4 rotates the drive cam 47d and stores energy in the biasing spring. When the rotation angle reaches a predetermined angle, the staple head portion 47b rapidly descends toward the anvil member 47c. In this operation, the staple needle is bent into a U-shape and then pierced into the sheet bundle by the driver. Then, its tip is bent by the anvil member 47c to be stapled.

[0087] A needle feeding mechanism is incorporated between the needle cartridge 52 and the staple head 47b, and a sensor (empty sensor) for detecting the absence of needles is arranged in the needle feeding mechanism. Also, a cartridge sensor (not shown) for detecting whether the needle cartridge 52 is inserted is arranged on the unit frame 47a.

[0088] The staple cartridge 52 has a structure in which staple pins connected in a strip shape are stacked and stored in a box-shaped cartridge, and a structure in which they are stored in a roll shape. Further, the unit frame 47a is provided with a circuit for controlling each of the above sensors and a circuit board for controlling the drive motor M4, and is configured to issue a warning signal when the staple cartridge 52 is not stored or when the staple pins are empty. Further, the staple control circuit controls the drive motor M4 so as to execute a staple operation with a staple pin signal, and is configured to transmit an "operation end signal" when the staple head portion 47b moves from the standby position to the staple position and returns to the standby position again.

[0089] <Description of Control Configuration> The control configuration in the image forming system of FIG. 1 will be described with reference to FIG. 14. The image forming system shown in FIG. 14 includes a control unit 90 (hereinafter referred to as "main body control unit") of the image forming apparatus A and a control unit 95 (hereinafter referred to as "binding process control unit") of the sheet post-processing apparatus B. The main body control unit 90 controls a print control unit 91, a paper feed control unit 92, and an input unit 93 (control panel).

[0090] Then, based on the user operation received via the input unit 93 (control panel), settings for "image forming mode" and "post-processing mode" are made. In the image forming mode, for example, mode settings such as color / monochrome printing, double-sided / single-sided printing, and image forming conditions such as sheet size, sheet paper quality, number of printed copies, and enlarged / reduced printing are set. Also, in the "post-processing mode", for example, "printed copy mode", "bookbinding process paper discharge mode", "staple binding process mode", and "jogging sorting mode" are set.

[0091] Further, the main body control unit 90 transfers data such as the fact that it is the post-processing mode, the number of sheets, the number of copies, and the paper thickness information of the sheet on which the image is to be formed to the binding process control unit 95. At the same time, the main body control unit 90 transfers a job end signal to the binding process control unit 95 each time image formation is completed.

[0092] Regarding the above post-processing mode, the "printout mode" is a mode in which the sheet from the straight path paper discharge port 35 is accommodated in the stack tray 49 via the processing tray 37 without being stapled. In this case, the sheets are stacked and accumulated on the processing tray 37, and the stacked sheet bundle is carried out to the stack tray 49 by a job end signal from the main control unit 90.

[0093] The "product processing paper discharge mode" is a mode in which the sheet on which an image is formed is collated, stapled, folded, and then bookbinding-finished. Details will be described later with reference to FIG. 15.

[0094] The "staple binding processing mode" is a mode in which the sheets from the straight path paper discharge port 35 are accumulated and collated on the processing tray 37, and after the sheet bundle is stapled, it is accommodated in the stack tray 49. In this case, the sheets to be image-formed are specified by the operator so that they are generally sheets of the same paper thickness and the same size. In this staple binding processing mode, any one of "multi-binding", "right corner binding", and "left corner binding" is selected and specified.

[0095] In the " jog sorting mode", the sheets image-formed by the image forming apparatus A are divided into a group that is offset and accumulated and a group that is accumulated without offset movement. In the stack tray, the sheet bundles that are alternately offset and the sheet bundles that are not offset are stacked.

[0096] <Stapling processing control unit> The stapling processing control unit 95 operates the sheet post-processing apparatus B according to the post-processing mode set by the image forming control unit 90. The stapling processing control unit 95 is configured to include a control CPU. A ROM 96 and a RAM 97 are connected to the stapling processing control unit 95, and the operation of the sheet post-processing apparatus B in the present embodiment is executed by the control program stored in the ROM 96 and the control data stored in the RAM 97. For this reason, the stapling processing control unit 95 controls the drive circuits of all the drive motors described above, and controls the start, stop, and forward / reverse rotation of each motor.

[0097] Even while post - processing is being performed in the processing unit B1, image formation continues to be performed by the image forming apparatus A. Therefore, in this embodiment, a buffer operation is performed to store the sheets conveyed from the image forming apparatus A in the sheet processing apparatus B. As a result, post - processing can be continued without reducing the frequency at which sheets are supplied from the image forming apparatus A, that is, without reducing the productivity of the image forming apparatus A.

[0098] With reference to FIGS. 15 to 30, an outline of the sheet buffer operation in the sheet post - processing apparatus B will be described. FIGS. 15 to 29 show cross - sectional views seen from the side direction of the sheet post - processing apparatus B. FIG. 30 is a diagram showing the configuration around the processing unit buffer path flapper 200. Hereinafter, the buffer operation of subsequent sheets when there is a preceding sheet bundle on the tray 37 of the binding unit 47 will be described. For example, when the binding process control unit 95 acquires sensor information provided in the binding unit 47 and detects that there is a preceding sheet bundle, it performs the following processing.

[0099] In FIG. 15(a), the sheet bundle SS1 represents a preceding sheet bundle and is in a state where binding processing is being performed by the binding unit 47. In this example, the number of sheets in the sheet bundle being bound by the binding unit 47 is three. Note that the number of sheets in the sheet bundle is not limited to three and may be less than three or more than three. In FIG. 15(a), the upper conveyance path flapper 34 is open upward, so that the sheets conveyed on the straight path 28 are conveyed in the direction of the lifting roller 41 and the driven roller 48. Also, at this time, the sheet support 401 is in a standby position to be described later, and the processing unit buffer path flapper 200 can rotate downward. Also, during the binding process by the binding unit 47, the lifting roller 41 and the driven roller 48 are nipped to suppress bundle displacement.

[0100] Here, the possible positions of the sheet support 401 will be described. FIGS. 30(a) to 30(c) are enlarged views of the processing unit buffer path flapper 200 and the periphery of the sheet support 401. The processing unit buffer path flapper 200 provided between the second conveyance roller 202 and the third conveyance roller 203 is configured to be rotatable downward in the drawing direction.

[0101] FIG. 30(a) shows a state in which the processing unit buffer path flapper 200 is open upward and the sheet support 401 is positioned below the second conveyance roller 202. In the present embodiment, the position of the sheet support 401 at this time is referred to as the standby position. Also, in the state of FIG. 30(a), the processing unit buffer path flapper 200 can be rotated downward.

[0102] FIG. 30(b) shows a state in which the processing unit buffer path flapper 200 is open upward and the sheet support 401 has moved to the side of the processing unit buffer path flapper 200. In the present embodiment, the position of the sheet support 401 at this time is referred to as the support position. When the sheet support 401 is in the support position, the sheet conveyed from the second conveyance roller 202 side can be supported from below. With such a configuration, it is possible to prevent the leading edge of the sheet from drooping and causing jams or the like.

[0103] FIG. 30(c) shows a state in which the sheet support 401 is in the standby position and the processing unit buffer path flapper 200 has rotated downward. When the processing unit buffer path flapper 200 is in the state of rotating downward, the sheet conveyed from the third conveyance roller 203 side can be guided to the processing unit buffer path P1.

[0104] For example, in the sheet post-processing device B, the sheet conveyed from the side of the second conveying roller 202 passes through the third conveying roller 203, and when the rear end of the sheet passes through the second conveying roller 202, the processing unit buffer path flapper 200 rotates downward, reverses the conveying direction of the sheet, and guides and conveys it to the processing unit buffer path P1 (reverse conveying). In order to perform such an operation quickly, the arm length of the processing unit buffer path flapper 200 is configured to be long. On the other hand, as the rotation space of the processing unit buffer path flapper 200 increases, the distance between the second conveying roller 202 and the third conveying roller 203 increases. As a result, there is a high possibility that the tip of the sheet conveyed from the side of the second conveying roller 202 will sag, causing jams and the like. In the present embodiment, when conveying the sheet on the straight path 28 composed of the second conveying roller 202 and the third conveying roller 203, the sheet support 401 is moved to the support position as shown in FIG. 30(b). Thereby, the above-mentioned situation can be prevented.

[0105] In FIG. 15(b), the upper conveying path flapper 34 changes from the state of being opened upward to the state of being opened downward. Thereby, the sheet conveyed on the straight path 28 is conveyed to the upper conveying path 30. Also, the sheet support 401 moves to the support position. Thereby, the sheet conveyed on the straight path 28 is supported from below by the sheet support 401.

[0106] The upper conveyance path 30 is intended to prevent the subsequent sheet from protruding toward the elevating roller 41 and the driven roller 48 during buffering. There are various cases regarding the timing when the subsequent sheet is conveyed. When there is a sheet on the tray 37 of the binding unit 47, the elevating roller 41 and the driven roller 48 are either at the timing of nipping and stopping or at the timing of nipping and performing bundle discharge at a low speed. At such timing, a subsequent sheet that is conveyed at a speed higher than the bundle discharge speed and is longer than a predetermined length will be blocked at the nipping position of the elevating roller 41 and the driven roller 48 of the binding unit 47 and cannot be conveyed to a position where buffering is possible. For such reasons, a subsequent sheet that is longer than a predetermined length is once fed into the upper conveyance path 30, and a buffering operation is performed without discharging the subsequent sheet that is longer than a predetermined length toward the elevating roller 41 and the driven roller 48 side.

[0107] FIG. 16(a) shows a state where the sheet S1 is sent from the image forming apparatus A. The sheet S1 corresponds to the first sheet among the sheet bundle processed in the subsequent binding unit 47. In FIG. 16(a), the sheet S1 is shown in a state of being conveyed to the second conveyance roller 202. As described above, since the sheet support 401 has moved to the support position, it is possible to prevent the leading edge of the sheet S1 from drooping downward and causing a jam or the like.

[0108] FIG. 16(b) shows a state where the sheet S1 is conveyed to the upper conveyance roller 303a. Thus, when it is at the timing from during the binding process of the preceding sheet bundle SS1 in the binding unit 47 until immediately before bundle discharge, the subsequent sheet sent from the image forming apparatus A can be retracted to the upper conveyance path 30.

[0109] FIG. 17(a) shows a state where the sheet S1 is conveyed to the upper conveyance roller 303b. At this time, the processing of the binding unit 47 for the preceding sheet bundle SS1 is completed, and the discharge of the preceding sheet bundle SS1 to the first tray 49 has started.

[0110] Figure 17(b) shows a state where the conveyance direction of the sheet S1 is reversed and the sheet S1 is conveyed to the position of the punch unit 100. Then, the punch unit 100 punches a punch hole in the sheet S1. At this time, the preceding sheet bundle SS1 is discharged to the first tray 49.

[0111] Figure 18(a) shows a state where, after the punching process of the punch hole by the punch unit 100, the conveyance direction of the sheet S1 is reversed and the sheet S1 is conveyed again to the upper conveyance path 30. The sheet S1 is conveyed to a position where the rear end has passed through the second conveyance roller 202. Then, the sheet support 401 moves from the support position to the standby position. As a result, the processing unit buffer path flapper 200 can be rotated downward.

[0112] Figure 18(b) shows a state where the conveyance direction of the sheet S1 is reversed and the conveyance direction of the sheet S1 is changed by the rotation of the processing unit buffer path flapper 200. As a result, the sheet S1 is reversely conveyed to the processing unit buffer path P1.

[0113] Figure 19(a) shows a state where the sheet S1 passes through the processing unit buffer roller 301a and is conveyed on the processing unit buffer path P1.

[0114] Figure 19(b) shows a state where the processing unit buffer roller 301a stops and the sheet S1 has retreated to the processing unit buffer path P1. Also, it shows a state where the sheet S2 has been sent from the image forming apparatus A. The sheet S2 corresponds to the second sheet of the sheet bundle that is processed together with the sheet S1 in the subsequent binding unit 47. For the purpose of distinguishing between the sheets in the drawing, the sheet S2 is shown by a dotted line.

[0115] Figure 20(a) shows a state where the sheet support 401 has moved to the support position. As a result, it is possible to prevent the tip of the sheet S2 from drooping downward and causing a jam or the like, or from making an unexpected contact with the sheet S1 that has retreated to the processing unit buffer path P1.

[0116] FIG. 20(b) shows a state in which the sheets S1 and S2 are conveyed synchronously. In the present embodiment, the leading end of the sheet S1 is conveyed with a predetermined interval delay from the leading end of the sheet S2. The synchronization of the conveyance operation between the sheets here is performed, for example, by conveyance control based on pulse counting based on the detection timing when the sheet is supplied from the image forming apparatus A to the straight path inlet 26. As a result, the leading ends of the respective sheets of the sheet bundle are shifted in order. Therefore, when the sheet bundle is scraped into the rear end portion of the paper placement surface 37a of the processing tray 37 by the scraping rotating body 46 at the subsequent stage, it will sequentially contact the rear end portion, and the leading end portions of all the sheets of the sheet bundle can be operated so as to contact the rear end portion in a state where they are aligned.

[0117] FIG. 21(a) shows a state in which the sheets S1 and S2 overlap and are conveyed synchronously on the upper conveyance path 30. Here, the rear end of the sheet S2 has passed through the punching unit 100. Then, when the sheets S1 and S2 are conveyed to a predetermined position on the upper conveyance path 30, the conveyance directions of the sheets S1 and S2 are reversed.

[0118] FIG. 21(b) shows a state in which the conveyance directions of the sheets S1 and S2 are reversed and the sheet S2 is conveyed to the punching unit 100. Here, the sheet S1 is conveyed to the processing unit buffer path P1. Also in the conveyance here, the sheets S1 and S2 are conveyed synchronously. Then, the punching unit 100 punches a punch hole in the sheet S2.

[0119] FIG. 22(a) shows a state in which the punching unit 100 has moved to the retracted position after the punching unit 100 has punched the punch hole.

[0120] Figure 22(b) shows a state in which the conveyance directions of the sheet S1 and the sheet S2 are reversed, and the sheet S1 and the sheet S2 are overlapped and conveyed synchronously to a predetermined position on the upper conveyance path 30. Then, the sheet support 401 moves from the support position to the standby position. As a result, the processing unit buffer path flapper 200 can be rotated downward.

[0121] Figure 23(a) shows a state in which the conveyance directions of the sheet S1 and the sheet S2 are reversed, and the conveyance direction of the sheet is changed by the rotation of the processing unit buffer path flapper 200. As a result, the sheet S1 and the sheet S2 are guided to the processing unit buffer path P1. Also in the conveyance here, the sheet S1 and the sheet S2 are conveyed synchronously.

[0122] Figure 23(b) shows a state in which the processing unit buffer roller 301a has stopped and the sheet S1 and the sheet S2 have been retracted to the processing unit buffer path P1.

[0123] Figure 24(a) shows a state in which the sheet S3 has been sent from the image forming apparatus A. The sheet S3 corresponds to the third sheet (the final sheet) of the sheet bundle to be processed in the subsequent binding unit 47. At this time, the sheet support 401 moves from the standby position to the support position. As a result, it is possible to prevent the leading end of the sheet S3 from hanging downward and causing a jam or the like, or from coming into unexpected contact with the sheet S1 and the sheet S2 retracted to the processing unit buffer path P1. Also at this time, the upper conveyance path flapper 34 changes from the state of being opened downward to the state of being opened upward.

[0124] Figure 24(b) shows a state in which the processing unit buffer roller 301a rotates, and further, the sheet S3, the sheet S1, and the sheet S2 are overlapped and conveyed synchronously. In the present embodiment, the leading end of the sheet S2 is conveyed so as to be delayed by a predetermined interval from the leading end of the sheet S3. The synchronization of the conveyance operation between the sheets here is performed, for example, by conveyance control based on pulse counting based on the detection timing when the sheet is supplied from the image forming apparatus A.

[0125] Figure 25(a) shows a state in which sheet S3, sheet S1, and sheet S2 are overlapped and conveyed synchronously. Here, since the upper conveyance path flapper 34 is in an upwardly open state, sheet S1, sheet S2, and sheet S3 are conveyed in the direction of the elevating roller 41 and the driven roller 48.

[0126] Figure 25(b) shows a state in which the conveyance direction of sheet S3, sheet S1, and sheet S2 is reversed and sheet S3 is conveyed to the punch unit 100. Here, sheet S3, sheet S1, and sheet S2 are conveyed to the processing unit buffer path P1. Also in this conveyance, sheet S3, sheet S1, and sheet S2 are conveyed synchronously. Then, the punch unit 100 punches punch holes in sheet S3.

[0127] Figure 26(a) shows a state in which after the punch holes are punched by the punch unit 100, the punch unit 100 has moved to the retracted position.

[0128] Figure 26(b) shows a state in which the conveyance direction of sheets S1 to S3 is reversed and sheet S3, sheet S1, and sheet S2 are overlapped and conveyed synchronously.

[0129] Figure 27(a) shows a state in which the rear ends of sheets S1 to S3 are conveyed to a position where they pass through the paper discharge roller 36. Then, by reversing the elevating roller 41 and the driven roller 48, the sheet bundle of sheets S1 to S3 is conveyed to the binding unit 47.

[0130] Figure 27(b) shows a state in which the sheet bundle of sheets S1 to S3 is scraped into the rear end portion of the paper placement surface 37a of the processing tray 37 by the scraping rotating body 46.

[0131] FIG. 28(a) shows how the binding unit 47 performs binding processing on the stack of sheets S1 to S3. FIG. 28(b) shows how the stack of sheets SS2 of sheets S1 to S3 is discharged onto the first tray 49 by the lifting roller 41 and the driven roller 48 after the binding processing by the binding unit 47. FIG. 29 shows the state where the stack of sheets SS2 of sheets S1 to S3 is discharged onto the first tray 49.

[0132] The buffer operation of this embodiment is effective when there is a stack of sheets preceding on the processing tray 37 of the binding unit 47 and the subsequent sheet is a sheet of a predetermined size that is longer than a predetermined length. Specifically, this predetermined size sheet refers to a sheet type such as A3 size that has a long conveyance direction length and requires high productivity. Special long sheets or the like that inevitably slow down the productivity of the image forming apparatus main body may not require buffering. Note that the sheet size information uses the sheet information included in the print setting information transmitted from the image forming apparatus main body.

[0133] Whether the subsequent sheet corresponds to a predetermined size sheet is determined by how far the leading edge of the subsequent sheet protrudes onto the processing tray 37 when the trailing edge of the sheet is located at the branch of the buffer path P1. Since the lifting roller 41 and the driven roller 48 are nipped and stopped during the binding process of the binding unit 47, if the subsequent sheet that protrudes from the paper discharge roller 36 reaches the nip point of the lifting roller 41 and the driven roller 48, it will be blocked and cannot be buffered. On the other hand, if the subsequent sheet that protrudes from the paper discharge roller 36 does not reach the nip point of the lifting roller 41 and the driven roller 48, it may be switched back and conveyed from the state of remaining in the straight path 28 without sending the sheet to the upper conveyance path 30 and put into the buffer path P1. In this case, it can be conveyed only by the third conveyance roller 203, so the number of rollers to be driven can be reduced.

[0134] Also, in this embodiment, although the case where the bundles of sheets of the above-described predetermined size, that is, sheets having a long conveyance direction length, are continuously stapled has been described, it is also effective when connecting different jobs. For example, if the sheet bundle on the processing tray 37 of the stapling unit 47 is a preceding job for stapling a sheet bundle of A4 size, and the subsequent job discharges at least one A3-size sheet to the first tray 49, it can be sent out without delaying the image formation of the A3 sheet of the subsequent job.

[0135] As described above, according to this embodiment, in a configuration in which post-processing is performed on the sheets continuously supplied from the image forming apparatus A, productivity can be further improved. In the above description, the operation when the preceding sheet bundle SS1 exists has been described. When the preceding sheet bundle SS1 does not exist, the above-described buffer operation is not performed on the sheets supplied from the image forming apparatus A. In that case, for example, the sheets supplied from the image forming apparatus A are reversely conveyed from the straight path 28 to the processing unit buffer path P1 without performing the buffer operation to the upper conveyance path 30, and then, in synchronization with the sheets newly supplied to the straight path inlet 26 from the image forming apparatus A, they are conveyed to the elevating roller 41 and the driven roller 48. Then, when the elevating roller 41 and the driven roller 48 reverse, the sheet bundle is conveyed to the stapling unit 47.

[0136] Also, the upper conveyance path 30 is also used as a path for discharging sheets to the third stack tray 71. The third stack tray 71 stacks sheets of a different job that avoids mixed loading with the first stack tray 49. It can also be used to discharge sheets determined to be error sheets by an image error recognition unit (not shown) or sheets remaining in the apparatus at the time of an apparatus jam.

[0137] In this embodiment, the binding process of the binding unit 47 has been described by taking the binding process using a needle as an example. However, various methods such as pressure binding by pressing the sheets and performing the binding process at multiple locations can be adopted. Even when performing time-consuming post-processing, the image forming apparatus can operate without stopping its operation. Further, by feeding the subsequent sheet into the upper conveyance path 30, in addition to avoiding the nip point of the lifting roller 41 and the driven roller 48, it is also possible to avoid contact with the sheet on the processing tray 37, without disturbing the alignment of the stacked sheets, and without contacting other mechanisms within the processing tray 37.

[0138] The disclosure of this embodiment includes the following sheet binding processing apparatus and an image forming system including the sheet binding processing apparatus. (Item 1) A conveyance path through which a sheet is conveyed from an inlet to an outlet, A conveyance unit provided in the conveyance path for conveying the sheet, A processing tray for receiving the sheet conveyed through the conveyance path from above, A binding processing unit for performing a binding process on the bundle of sheets on the processing tray, A pair of discharge rollers for discharging the bundle of sheets on which the binding process has been performed by the binding processing unit, A buffer path that branches downward from the conveyance path and buffers the sheets constituting the subsequent sheet bundle when there is a bundle of sheets preceding the processing tray, A buffer conveyance unit provided in the buffer path for conveying the sheet, An upper branch path that branches upward from the conveyance path, An upper branch conveyance unit provided in the upper branch path for conveying the sheet, When continuously performing the binding process on a bundle of predetermined sheets that are longer than a predetermined length in the conveyance direction by the binding processing unit, after feeding the sheets constituting the subsequent sheet bundle from the conveyance path into the upper branch path, the conveyance unit, the buffer conveyance unit, and the upper branch conveyance unit are controlled to convey the sheet from the upper branch path to the buffer path in a switchback direction for buffering. A sheet binding processing apparatus characterized by comprising (Item 2) When the subsequent sheet is a predetermined sheet shorter than a predetermined length in the conveyance direction, the control means controls to convey the sheet in the switchback direction to the buffer path and buffer it without feeding it into the upper branch path from the conveyance path. The sheet binding processing apparatus according to Item 1, characterized in that (Item 3) A first stack tray for placing the sheet discharged by the discharge roller pair, A second stack tray provided above the first stack tray, further comprising: The sheet conveyed through the conveyance path can be conveyed to the upper branch path and discharged to the second stack tray. The sheet binding processing apparatus according to Item 1 or 2, characterized in that (Item 4) An image forming apparatus for performing image formation on a sheet, The sheet binding processing apparatus according to any one of Items 1 to 3, An image forming system characterized by comprising (Item 5) A conveyance path through which a sheet is conveyed from an inlet to an outlet, A conveyance unit provided in the conveyance path for conveying the sheet, A processing tray for receiving the sheet conveyed through the conveyance path from above, A binding processing unit for performing a binding process of binding a bundle of sheets on the processing tray, A discharge roller pair for discharging the bundle of sheets on which the binding process has been performed by the binding processing unit, A buffer path that branches downward from the conveyance path and buffers the sheet of the subsequent job when there is a bundle of sheets of the preceding job on the processing tray, A buffer conveyance unit provided in the buffer path for conveying the sheet, An upper branch path that branches upward from the conveyance path, An upper branch conveyance unit provided in the upper branch path for conveying the sheet, When there is a bundle of sheets of a preceding job on the processing tray and the sheet of a subsequent job is a predetermined sheet that is longer than a predetermined length in the conveyance direction, after sending the sheet of the subsequent job from the conveyance path into the upper branch path, the conveyance unit, the buffer conveyance unit, and the upper branch conveyance unit are controlled so that the sheet is conveyed in the switchback direction from the upper branch path to the buffer path and buffered. A sheet binding processing apparatus, characterized by comprising the same. (Item 6) When the subsequent sheet is a predetermined sheet that is shorter than a predetermined length in the conveyance direction, the control means controls to convey the sheet in the switchback direction to the buffer path without sending it from the conveyance path into the upper branch path and buffer it. The sheet binding processing apparatus according to Item 5. (Item 7) A first stack tray for placing the sheet discharged by the discharge roller pair; A second stack tray provided above the first stack tray, further comprising: The sheet binding processing apparatus according to Item 5 or 6, characterized in that the sheet conveyed through the conveyance path can be conveyed to the upper branch path and discharged to the second stack tray. (Item 8) An image forming apparatus for performing image formation on a sheet; The sheet binding processing apparatus according to any one of Items 5 to 7; An image forming system, characterized by comprising the same.

Claims

1. a conveying path along which the sheet is conveyed from the entrance to the discharge port; a conveying unit provided in the conveying path and configured to convey a sheet; a processing tray that receives the sheet conveyed along the conveying path from above; a binding processing unit that performs a binding process for binding the sheet bundle on the processing tray; a pair of discharge rollers for discharging the sheet bundle that has been bound by the binding processing unit; a buffer path that branches downward from the conveying path and buffers sheets constituting a succeeding sheet stack when a preceding sheet stack is present on the processing tray; a buffer conveying unit provided in the buffer path and configured to convey a sheet; an upper branch path that branches upward from the conveying path; an upper branch conveying section provided in the upper branch path and configured to convey a sheet; a control means for controlling the conveying section, the buffer conveying section, and the upper branch conveying section so that, when a stack of predetermined sheets having a length longer than a predetermined length in a conveying direction is continuously bound by the binding processing section, a sheet constituting a succeeding stack of sheets is sent from the conveying path to the upper branch path, and then the sheet is conveyed in a switchback direction from the upper branch path to the buffer path for buffering; A sheet binding processing device comprising:

2. The sheet binding processing device according to claim 1, characterized in that, when the subsequent sheet is a specified sheet having a length shorter than a specified length in the conveying direction, the control means controls the subsequent sheet to be conveyed in a switchback direction to the buffer path and buffered without being sent from the conveying path to the upper branch path.

3. a first stack tray on which the sheets discharged by the pair of discharge rollers are placed; A second stack tray provided above the first stack tray, 2 . The sheet binding processing device according to claim 1 , wherein the sheet conveyed along the conveying path is conveyed to the upper branch path and is capable of being discharged onto the second stack tray.

4. an image forming apparatus for forming an image on a sheet; The sheet binding device according to claim 1 ; An image forming system comprising:

5. a conveying path along which the sheet is conveyed from the entrance to the discharge port; a conveying unit provided in the conveying path and configured to convey a sheet; a processing tray that receives the sheet conveyed along the conveying path from above; a binding processing unit that performs a binding process for binding the sheet bundle on the processing tray; a pair of discharge rollers for discharging the sheet bundle that has been bound by the binding processing unit; a buffer path that branches downward from the conveying path and buffers sheets of a subsequent job when a sheet stack of a preceding job is present on the processing tray; a buffer conveying unit provided in the buffer path and configured to convey a sheet; an upper branch path that branches upward from the conveying path; an upper branch conveying section provided in the upper branch path and configured to convey a sheet; a control means for controlling the conveying unit, the buffer conveying unit, and the upper branch conveying unit so that, when a sheet bundle of a preceding job is present on the processing tray and a sheet of a subsequent job is a predetermined sheet longer than a predetermined length in a conveying direction, the sheet of the subsequent job is sent from the conveying path to the upper branch path, and then the sheet is conveyed in a switchback direction from the upper branch path to the buffer path for buffering; A sheet binding processing device comprising:

6. The sheet binding processing device according to claim 5, characterized in that, when the subsequent sheet is a specified sheet having a length shorter than a specified length in the conveying direction, the control means controls the subsequent sheet to be conveyed in a switchback direction to the buffer path and buffered without being sent from the conveying path to the upper branch path.

7. a first stack tray on which the sheets discharged by the pair of discharge rollers are placed; A second stack tray provided above the first stack tray, 6. The sheet binding processing device according to claim 5, wherein the sheet conveyed along the conveying path is conveyed to the upper branch path and is capable of being discharged onto the second stack tray.

8. an image forming apparatus for forming an image on a sheet; The sheet binding device according to claim 5 ; An image forming system comprising:

Images