Sheet processing apparatus

Abstract

In a sheet processing apparatus that performs post-processing by conveying a sheet to a processing tray, when a leading end of the sheet reaches a stiffening member after a roller conveying the sheet starts to move in a sheet width direction until the roller finishes moving, an end edge of the sheet in the sheet width direction comes into contact with the stiffening member from the sheet width direction, and the sheet can be moved by a predetermined distance in the sheet width direction without the movement of the sheet being hindered by the stiffening member.SOLUTION: The stiffening member is provided with an inclined surface such that the sheet edge with respect to the sheet width direction can move in the sheet width direction.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] The present invention relates to a sheet processing apparatus for processing sheets. [Background technology]

[0002] Conventionally, there has been a sheet processing apparatus capable of forming an image on a sheet, transporting the sheet to a loading tray using a transport roller, and binding the sheet formed from multiple sheets loaded on the loading tray. This loading tray is sloped and has a step downward relative to the sheet transport direction so that the sheets transported by the transport rollers can be stacked under their own weight. As a result, after the leading edge of the sheet passes through the transport rollers, the leading edge is no longer supported by the rollers, and the edge of the sheet in the sheet width direction droops under its own weight. If the sheet continues to be transported in this state, the corner of the sheet drooping under its own weight may come into contact with the slope of the loading tray, and the corner of the sheet may move along the slope in the opposite direction to the transport direction, resulting in transport failure.

[0003] To prevent the sheet edge from sagging in the width direction due to its own weight, the sheet processing device described in Patent Document 1 uses stiffening members. These stiffening members are arranged in pairs in the width direction of the sheet, sandwiching the conveying rollers. By supporting the sheet above the support members that support the sheet conveyed by the conveying rollers, the amount of sagging in the width direction of the sheet due to its own weight is reduced. Furthermore, these stiffening members support the sheet at a position a predetermined distance inward from the widthwise edge of the sheet conveyed by the conveying rollers. This predetermined distance is designed to minimize the number of stiffening members required depending on the width of the sheet that can be conveyed, while minimizing sheet conveyance problems by reducing the amount of sheet edge sagging and preventing conveyance problems. These stiffening members effectively prevent sheet conveyance problems. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2020-93862 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, as a shifting means for moving a sheet a predetermined distance in the sheet width direction, there has been a shift roller that moves the sheet by moving a roller that conveys the sheet in the sheet width direction. Also, since the sheet conveying path has been shortened to make the product width as small as possible, if the length of the sheet is longer than a predetermined value, the leading edge of the sheet reaches the stiffening member from the time the shift roller starts to move the sheet a predetermined distance in the sheet width direction until the movement ends.

[0006] At this time, one edge of the sheet in the width direction is moved in the sheet width direction by the shift roller and comes into contact with the stiffening member. With conventional stiffening members, even if the edge of the sheet at the contact point tries to move in the sheet width direction, the stiffening member stops the movement, causing the sheet to sag and prevent it from moving. The edge of the sheet that cannot move passes through the shift roller, the deflection is eliminated, and it is pushed back into the stiffening member. This may prevent the sheet from moving a predetermined distance in the sheet width direction.

[0007] An object of the present invention is to provide a configuration in which the sheet can be moved a predetermined distance in the sheet width direction without being hindered by a stiffening member. [Means for solving the problem]

[0008] The present invention relates to a shift roller that conveys a sheet in a predetermined conveying direction and moves the sheet a predetermined distance in a sheet width direction that is a direction intersecting the predetermined conveying direction, conveying rollers that are in a nip state where they pinch the surface of the sheet conveyed by the shift rollers and convey the sheet in the predetermined conveying direction, and a separated state where they are separated from the surface of the sheet conveyed by the shift rollers from when the sheet starts to move the predetermined distance in the sheet width direction by the shift rollers until the movement ends, a support member that supports the sheet conveyed by the conveying rollers, a loading tray that is arranged below the first conveying roller and on which the sheets conveyed by the first conveying rollers are placed, a stapler that can perform a binding process on a sheet bundle formed of a plurality of sheets placed on the loading tray, and a stapler that can bind the sheet bundle formed of a plurality of sheets placed on the loading tray. The sheet conveyed in the predetermined conveying direction by the feed rollers is provided with a conveying direction inclined surface that allows the sheet to be conveyed in the predetermined conveying direction, and a stiffening member that is positioned inside the sheet a predetermined distance extending in the sheet width direction from both end edges of the sheet conveyed by the conveying rollers in the sheet width direction and supports the sheet at a higher position than the support member, and the stiffening member is characterized in that when one end edge in the sheet width direction of the sheet that is moved a predetermined distance in the sheet width direction by the shift rollers comes into contact with the stiffening member after the sheet starts to move a predetermined distance in the sheet width direction by the shift rollers and before the movement ends, the stiffening member is provided with a moving direction inclined surface that allows the one end edge to move a predetermined distance in the sheet width direction. [Effects of the Invention]

[0009] According to the present invention, the sheet can be conveyed while moving the sheet by a predetermined distance in the sheet width direction. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an external appearance of an image forming system. [Figure 2] FIG. 2 is a diagram illustrating a configuration of a sheet post-processing device. [Figure 3] FIG. 10 is a diagram showing a configuration in the vicinity of a straight path. [Figure 4] FIG. 2 is a diagram showing the configuration of a punch unit. [Figure 5] FIG. 2 is a diagram showing the configuration of a punch unit. [Figure 6] FIG. 10 is a diagram illustrating a shift mechanism of the conveying roller. [Figure 7] FIG. 10 is a diagram illustrating a shift mechanism of the conveying roller. [Figure 8] FIG. 10 is a diagram illustrating a binding mechanism. [Figure 9] FIG. 10 is a diagram illustrating a binding mechanism. [Figure 10] FIG. 10 is a diagram illustrating a binding mechanism. [Figure 11] FIG. 10 is a diagram illustrating a tray lifting mechanism. [Figure 12] FIG. 10 is a diagram illustrating a sheet discharge mechanism. [Figure 13] FIG. 2 is a diagram showing a configuration of a staple unit. [Figure 14] FIG. 2 is a diagram showing the configuration of a control unit and its surroundings. [Figure 15] 10A and 10B are diagrams illustrating the arrangement of stiffness enhancing members and paper discharge rollers. [Figure 16] FIG. 4 is a cross-sectional view showing the arrangement of a stiffening member and a paper discharge roller. [Figure 17] 5 is a schematic diagram showing the positional relationship between a stiffening member and a paper discharge roller. FIG. [Figure 18] FIG. 10 is a diagram illustrating a stiffness enhancing member. [Figure 19] 10A and 10B are diagrams illustrating a case where a sheet comes into contact with a stiffening member while being shifted in the width direction by a shift mechanism of a conveying roller. [Figure 20] 10 is a schematic diagram illustrating a case where a sheet comes into contact with a stiffening member while being shifted in the width direction by a shift mechanism of a conveying roller. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] [Image forming device] An image forming apparatus A in the image forming system shown in Figure 1 will now be described. The image forming apparatus A shown in the figure is an electrostatic printing mechanism, and is composed of an image forming unit A1, a scanner unit A2, and a feeder unit A3. The apparatus housing 1 is provided with mounting legs 25 for installation on an installation surface (for example, the floor). Inside the apparatus housing 1, a paper feed unit 2, an image forming unit 3, a paper discharge unit 4, and a data processing unit 5 are built in.

[0013] The paper feed unit 2 is configured to include cassette mechanisms 2a to 2c that store sheets of multiple sizes on which images are to be formed, and feeds sheets of a size specified by the main body control unit 90 shown in Fig. 14 to the paper feed path 6. For this purpose, multiple cassettes 2a to 2c are detachably arranged in the device housing 1, and each cassette has a built-in separation mechanism that separates the sheets inside one by one, and a paper feed mechanism that feeds out the sheets. The paper feed path 6 is provided with transport rollers 7 that feed sheets supplied from the multiple cassettes 2a to 2c downstream, and a registration roller pair 8 that aligns the leading edges of each sheet at the end of the path.

[0014] In addition, a large-capacity cassette 2d and a manual feed tray 2e are connected to the paper feed path 6, and the large-capacity cassette 2d is configured to include an optional unit for storing sheets of a size that are consumed in large quantities, while the manual feed tray 2e is configured to be able to supply special sheets such as cardboard sheets, coated sheets, and film sheets that are difficult to separate and feed.

[0015] The image forming unit 3 is shown as an example of an electrostatic printing mechanism, and includes a photosensitive member 9 (drum, belt), a light emitter 10 that emits an optical beam onto the photosensitive member 9, a developer 11 (developer), and a cleaner (not shown) arranged around the rotating photosensitive member. The illustrated example shows a monochrome printing mechanism, in which a latent image is optically formed on the photosensitive drum 9 by the light emitter 10, and toner ink is applied to the latent image by the developer 11. A sheet is then fed from a paper feed path 6 to the image forming unit 3 in synchronization with the image formation on the photosensitive member 9, where the image is transferred onto the sheet by a transfer charger 12 and fixed by a fixing unit (roller) 13 arranged in a paper discharge path 14. A downstream paper discharge roller 15 and a paper discharge outlet 16 are arranged in the paper discharge path 14, and the sheet is transported to a sheet post-processing device B (described later).

[0016] The scanner unit A2 is configured to include a platen 17 on which an image original is placed, a carriage 18 that moves back and forth 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 light reflected from the original on the platen 17 to a photoelectric conversion unit 19. Reference numeral 21 in the figure denotes a second platen (traveling platen), which reads an image on a sheet fed from the feeder unit A3 using the carriage 18 and reduction optical system 20. The photoelectric conversion unit 19 transfers the photoelectrically converted image data to the image forming unit 3.

[0017] The feeder unit A3 includes a paper feed tray 22, a paper feed path 23 that guides the document sent from the paper feed tray to a traveling platen 21, and a paper discharge tray 24 that stores the document after image reading on the platen.

[0018] The image forming apparatus A is not limited to the above mechanism, and can employ printing mechanisms such as an offset printing mechanism, an inkjet printing mechanism, and an ink ribbon transfer printing mechanism (thermal transfer ribbon printing, dye sublimation ribbon printing, etc.).

[0019] [Sheet post-processing device] The sheet post-processing device B is a device for post-processing sheets discharged from the paper discharge port 16 of the image forming device A and has, for example, (1) a function for stacking and storing image-formed sheets (printout mode), (2) a function for storing image-formed sheets in portions (jog sorting mode), (3) a function for collating and accumulating image-formed sheets and binding them (staple binding processing mode), and (4) a function for collating and stapling image-formed sheets, and then folding them to complete the binding process (binding processing paper discharge mode).

[0020] In this embodiment, the sheet post-processing device B does not need to have all of the above functions, and is configured appropriately according to the device specifications (design specifications). As an example, in this embodiment, it is assumed that the sheet post-processing device B has a function of collating and binding image-formed sheets, and then folding and finishing the sheets into a book.

[0021] FIG. 2 shows the configuration of the sheet post-processing device B, and FIG. 3 shows the configuration around the straight path 28. The sheet post-processing device B post-processes sheets conveyed through a straight path entrance 26 connected to the paper discharge outlet 16 of the image forming device A, and then stores the sheets in a storage unit (a first stack tray 49, a second stack tray 61, and a third stack tray 71, which will be described later). The illustrated device transfers sheets sent to the straight path 28 from a processing unit B1, which includes a 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"). Furthermore, the sheet sent to the straight path 28 is transferred from a saddle unit B2 to the second stack tray 61 (hereinafter referred to as the "second tray"). Since the straight path 28 is formed in a substantially straight line, even thick paper can be transported.

[0022] Processing section B1 is disposed at the path exit (straight path paper discharge outlet 35) of straight path 28, and collates and stacks sequentially fed sheets, performs a binding process, and stores them in first tray 49. Saddle section B2 is disposed at the path exit (saddle path paper discharge outlet) of saddle path 32 branching off from straight path 28, and is a post-processing section that collates and stacks sequentially fed sheets, saddle-stitches them (although saddle-stitching may not be performed), folds them, and stores them in second tray 61. Each component will be described in detail below.

[0023] <Device housing> The sheet post-processing device B includes a device housing 27 shown in Fig. 1, a straight path 28 built into the device housing and having a straight path inlet 26 and a straight path discharge outlet 35 as shown in Fig. 3, a processing section B1 and a saddle section B2 that perform post-processing on sheets fed from the straight path 28, and a first tray 49, a second tray 61, and a third tray 71 that store sheets fed from each post-processing section as shown in Fig. 2. The device housing 27 shown in Fig. 1 is disposed at approximately the same height as the housing 1 of the image forming device A located upstream, and the discharge outlet 16 of the image forming device A is connected to the straight path inlet 26 of the sheet post-processing device B shown in Fig. 3 on the installation surface.

[0024] The housing 27 of the seat post-processing device includes a device frame 70. The device frame 70 forms the framework of a box-shaped device, as shown in FIG. 6, and includes a front side frame 70f located at the front in the state shown in FIG. 1, a rear side frame 70r located at the rear, and stay members (connecting reinforcement members) connecting the two side frames. The straight path 28, processing section B1, saddle section B2, etc. are attached between the left and right side frames. The device housing 27 is not limited to the shape shown in the figure and can have any suitable shape in terms of design, and the device frame 70 is not limited to a structure consisting of left and right side frames and connecting stays, but various frame structures such as a monocoque structure can be used.

[0025] <Sheet delivery route> As shown in FIG. 3 , the straight path 28 is configured as a substantially linear path that crosses the device housing 27 in a substantially horizontal direction, and includes a straight path entrance 26 that is connected to the paper discharge outlet (main body paper discharge outlet) 16 of the image forming device A, and a straight path paper discharge outlet 35 located on the opposite side of the device from the entrance (straight path entrance 26). The straight path 28 is arranged, in order from the straight path entrance 26 side, as a conveying mechanism that can convey a sheet from the straight path entrance 26 to the straight path paper discharge outlet 35 and from the straight path paper discharge outlet 35 to the straight path entrance 26. In addition, the straight path paper discharge outlet 35 is arranged with a paper discharge roller 36 (including a sheet conveying mechanism such as a belt) as a conveying mechanism. In other words, the straight path 28 is arranged with a plurality of rollers that convey a sheet. The discharge rollers 36 can be operated in a nip state where they nip the surface of the sheet and transport it, or in a separated state where they are separated from the surface of the sheet. The straight path 28 can also be considered the main transport path for sheets, extending from the straight path entrance 26, which is the sheet receiving port, to the straight path discharge outlet 35, which is the sheet discharge outlet. Near the straight path entrance 26, an entrance sensor S1 is located to detect the leading and trailing edges of the received sheet, and a lateral registration detection sensor S0 (detection unit) is located to detect the edge position (side edge) of the sheet parallel to the transport direction. Near the straight path discharge outlet 35, a discharge sensor S2 is located to detect the leading and trailing edges of the sheet. The sheet discharged from the straight path discharge outlet 35 is discharged to the first tray 49 via the first discharge path 31 connected to the straight path discharge outlet 35, or is guided to the processing unit B1. A punch unit 100 is located on the straight path 28 to punch holes in the sheet.

[0026] <Sheet delivery route layout> As shown in FIGS. 2 and 3, the straight path 28 is arranged in the following order from the straight path entrance 26 toward the straight path discharge outlet 35: a saddle path 32, a saddle buffer path P2, a processing unit buffer path P1, and an upper conveying path 30. At the branching points of the above paths, a saddle path flapper 33b, a saddle buffer path flapper 33a, a processing unit buffer path flapper 200, and an upper conveying path flapper 34 are arranged as conveyance switching mechanisms (branching mechanisms) for conveyed sheets. In this embodiment, the saddle buffer path P2 and the upper conveying path 30 are configured as evacuation paths for evacuating sheets. Also, as shown in FIG. 2, a saddle section B2 is provided on one side of the straight path 28, and the saddle buffer path P2 and the upper conveying path 30 are provided on the opposite side (the other side).

[0027] Among the above paths, the saddle path 32, the saddle buffer path P2, and the processing section buffer path P1 are configured as switchback paths that transport a sheet in the opposite direction to the transport direction from the straight path entrance 26 to the straight path paper discharge outlet 35, and carry the sheet into each of the above paths. Also, the upper transport path 30 is configured so that the sheet is carried in by switching the sheet transport direction with the upper transport path flapper 34 while the rollers rotate in the same direction as the direction in which the rollers rotate to transport the sheet from the straight path entrance 26 to the straight path paper discharge outlet 35.

[0028] <Path branching mechanism> The sheet branching mechanisms, saddle path flapper 33b, saddle buffer path flapper 33a, and processing section buffer path flapper 200, are configured with flapper guides that move to switch the transport path of a sheet carried in through the straight path entrance 26, and are connected to a drive mechanism (not shown) such as an electromagnetic solenoid or a minimotor. The saddle path flapper 33b guides a sheet sent from the straight path entrance 26 to the saddle path 32. The saddle buffer flapper 33a guides a sheet sent from the straight path entrance 26 to the saddle buffer path P2. The processing section buffer flapper 200 guides a sheet sent from the straight path entrance 26 to the processing section buffer path P1 via a processing section buffer roller 301. The upper transport path flapper 34 is configured to include a flapper guide that moves to switch the transport path so that a sheet sent from the straight path entrance 26 is transported to either the straight path paper discharge outlet 35 or the upper transport path 30, and is connected to a drive mechanism (not shown) such as an electromagnetic solenoid or a minimotor.

[0029] <Upper transport path> An upper conveying path 30 (printout paper discharge path) that carries in sheets other than those to be discharged to the straight path paper discharge outlet 35 is connected to the straight path 28, and an upper conveying path flapper 34 for guiding sheets to the upper conveying path 30 is provided at the path branching portion. The upper conveying path 30 is also provided with upper conveying rollers 303 (303a, 303b) that guide sheets to the third tray 71. As a result, sheets guided to the upper conveying path 30 are discharged to the third tray 71 (overflow tray) from the upper conveying path paper discharge outlet 40. In this embodiment, the upper conveying path 30 is also used as a sheet evacuation path. In other words, the upper conveying rollers 303 are rollers that transport sheets on the evacuation path.

[0030] <Saddle Pass> A saddle path 32 for conveying sheets into the saddle section B2 is connected to the straight path 28, and the path branch section is provided with a saddle path flapper 33b for guiding sheets to the saddle path 32. Sheets guided from the saddle path 32 to the saddle section B2 via the saddle path paper discharge port are saddle-stitched and folded, and then discharged to the second tray 61 via the approximately horizontal saddle discharge path 68.

[0031] <Saddle buffer pass> A saddle buffer path P2 is connected to the straight path 28, and is used to temporarily transport and wait sheets to be saddle-stitched and folded in the saddle section B2. A saddle buffer path flapper 33a is provided to guide the sheets to the saddle buffer path P2. The saddle buffer path P2 is also provided with conveying rollers 302 (302a, 302b) that transport the sheets and temporarily wait them there.

[0032] A fourth tray discharge port 305 is provided on the downstream extension of the saddle buffer path P2, so that sheets carried into the saddle buffer path P2 can be discharged and stacked onto the fourth tray 310. In this case, the fourth tray 310 is disposed vertically above the saddle buffer path P2. The fourth tray 310 may be shared with an exterior component on the top surface of the sheet post-processing device B, may be fixed to the device housing, or may be provided with a drive mechanism and configured to be able to move up and down in a substantially vertical direction.

[0033] The device can be made more compact by arranging the saddle buffer path P2 in an overlapping position vertically above the punch unit 100. However, if space is required to flip the punch unit 100 upward to remove sheets retained in the punch unit 100, the saddle buffer path P2 may be arranged in a non-overlapping position vertically above the punch unit 100.

[0034] <Transport roller shift mechanism in the loading route> Here, the conveyance shift mechanism provided in the conveyance rollers on the conveyance path will be described with reference to Figures 6 and 7. The first conveyance roller 201, second conveyance roller 202, third conveyance roller 203, and conveyance rollers 302a and 302b shown in Figure 3 are configured to include a drive roller 111 and a driven roller 112 rotatably supported by bearings on left and right side frames 70f and 70r shown in Figure 6. A drive rotation shaft is connected to the drive roller shaft 113 by a transmission mechanism 116 (gear transmission in the illustration), and a drive motor (not shown) common to the sheet discharge roller 36 is connected to the drive rotation shaft 115. The driven roller shaft 114 is supported by bearings on the left and right side frames 70f and 70r so as to be able to move freely.

[0035] Each of the above-mentioned conveying rollers is rotatably attached to a shift member 117 that connects the drive roller shaft 113 and the driven roller shaft 114. The shift member 117 connects the drive roller shaft 113 and the driven roller shaft 114 so that they move together in the axial direction (thrust direction) and can rotate independently in the radial direction. The drive roller shaft 113 is supported by bearings on the left and right side frames 70f, 70r, with one end of the drive roller shaft 113 located in a range indicated by the axial movement region of the conveying roller on the front side of the side frame 70f and the other end located on the rear side of the side frame 70r. The shift member 117 (e.g., a block member made of synthetic resin) is supported by the drive roller shaft 113 and the driven roller shaft 114 and connects both roller shafts together.

[0036] A rack 117a is formed integrally with the shift member 117, and is engaged with a shift motor M9 and a transmission pinion 117b attached to the side frame 70r (device frame; the same applies below). With this configuration, the shift member 117 can be moved (shifted) in the axial direction of the conveying roller by rotating the shift motor M9 (the illustrated one is a stepping motor that can rotate forward and backward).

[0037] 7 is integrally formed with a driven gear 118, and the rotation of the drive motor is transmitted to the driven gear 118. A pair of conveying rollers (a drive roller and a driven roller) is pressed against the driven rotation shaft 119 so that the driven rotation shaft 119 is rotated by the rotation of the drive rotation shaft 115.

[0038] In this embodiment, the drive rotation shaft 115 and the driven rotation shaft 119 are connected to each other so that the axial movement of one of them causes the other to follow. Alternatively, one of the drive roller 111 and the driven roller 112 may be attached to the rotation shaft so that it can slide (slidably) in the axial direction, and the other roller may be moved in position in the axial direction and linked to that movement.

[0039] <Transport shift operation> Here, the shift operation (jog sorting mode) of a sheet carried into the sheet post-processing device B will be described. A sheet sent from the image forming device A is conveyed in the order of straight path entrance 26, entrance rollers 29, first conveyance rollers 201, second conveyance rollers 202, and third conveyance rollers 203 shown in FIG. 3. At this time, the timing of sheet delivery is also detected by entrance sensor S1. As the sheet carried in by entrance rollers 29 passes through the straight path 28, the edge position of the sheet is detected by lateral registration detection sensor S0. The lateral registration detection sensor S0 detects the extent to which a lateral registration error X occurs in the sheet relative to the center (middle) position.

[0040] When the lateral registration error X is detected by the lateral registration detection sensor S0, the first conveyance roller 201, the second conveyance roller 202, and the third conveyance roller 203 sequentially move a predetermined amount toward the front and rear while conveying the sheet, thereby performing a sheet shift operation (also referred to as "lateral registration detection process"). Thereafter, the sheet is conveyed by being sorted by the upper conveyance path flapper 34 of the branching mechanism to either the straight path paper discharge outlet 35 or the upper conveyance path 30, and is discharged onto the first tray 49 or the third tray 71.

[0041] <Processing section> Processing section B1 is a post-processing section that is disposed downstream of straight path 28 and includes a processing tray 37 that collates and stacks sheets sent from straight path paper discharge outlet 35, and a binding processing mechanism that binds the stacked sheet bundle. As shown in Fig. 3, a step is formed at straight path paper discharge outlet 35 of straight path 28, and processing tray 37 is disposed below the step, and a first paper discharge path (first switchback path) 31 is formed between straight path paper discharge outlet 35 and processing tray 37 that reverses the conveying direction from the paper discharge outlet and guides sheets onto the tray.

[0042] A sheet carry-in mechanism that carries sheets from the straight path paper discharge outlet 35 onto the tray is disposed between the straight path paper discharge outlet 35 and the processing tray 37, and the processing tray 37 is provided with a positioning mechanism that positions the sheets at a predetermined binding position and a sheet bundle carry-out mechanism that discharges the bound sheet bundle onto the downstream first tray 49. Each component will be described later.

[0043] 3 bridges the sheet fed from the straight path paper discharge outlet 35 between itself and the downstream first tray 49. That is, the sheet fed from the straight path paper discharge outlet 35 is supported in a bridge manner with its leading edge on the uppermost sheet of the downstream first tray 49 and its trailing edge on the processing tray 37.

[0044] <Saddle section> The saddle section B2 shown in Fig. 2 is a post-processing section that collates and stacks sheets, binds the center portion, and then folds the sheets inward (hereinafter referred to as "magazine finishing"). A second tray 61 is disposed downstream of the saddle section B2 and stores the bound sheet stack. Note that the configuration may also be such that one or more sheets are collated and stacked, and only folds the center portion inward without saddle stitching.

[0045] The saddle section B2 is configured to include a guide member 66 that accumulates sheets in a stack, a leading edge regulating stopper 67 that positions the sheets at a predetermined position on the guide member 66, a staple device 63 (saddle stitching staple unit) that binds the center of the sheets positioned by the leading edge regulating stopper 67, and a folding processing mechanism (a pair of folding rolls 64 and a folding blade 65) that folds the sheet stack at the center after the binding process.

[0046] The saddle stitch staple unit 63 employs a commonly known mechanism that sandwiches the sheet stack between a head unit and an anvil unit, and moves the unit along the center line of the sheets to perform the binding process. As shown in Figure 2, the folding process mechanism is configured so that a folding blade 65 inserts the fold of the sheet stack into a pair of folding rolls 64 that are pressed against each other, and the rolls roll to fold the sheet stack.

[0047] The illustrated processing section B1 and straight path 28 are arranged in a substantially horizontal direction, the saddle path 32 that guides the sheets to the saddle section B2 is arranged in a vertical direction, and the guide member 66 that aligns and stacks the sheets is arranged in a substantially vertical direction. In this way, by arranging the straight path 28 in a direction that crosses the device housing 27 and arranging the saddle path 32 and saddle section B2 in a vertical direction, it is possible to slim down the device.

[0048] A second tray 61 is disposed downstream of the saddle portion B2 and is capable of storing a stack of sheets folded like a magazine. The second tray 61 is disposed below the first tray 49. This is because it is assumed that the first tray 49 will be used more frequently than the second tray 61, and the position of the first tray 49 is set at a height that makes it easy to remove sheets from the tray.

[0049] <Punch unit> 5, a punch unit 100 that is disposed on the straight path 28 and punches holes in a sheet fed from the straight path inlet 26 will be described. The punch unit 100 has a plurality of punch members 101a to 101e arranged at predetermined intervals in a direction perpendicular to the sheet conveying direction of the straight path 28, and punches a selected number of holes in the sheet.

[0050] 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 on the unit frame 102 so as to be vertically movable, a drive cam that moves each punch member up and down (reciprocating in the punching direction), and a drive motor M7 that drives the drive cam.

[0051] Reference numeral 104 in Figure 5 denotes a waste box, which is located below the punch member 101 and stores punched waste paper. The waste box 104 is attached to a guide rail (not shown) so that it can slide on the device frame 70 (different from the unit frame). Reference numeral 106 in the figure denotes a rotation operation member, which forcibly rotates the drive cam to separate (peel off) the punch member 101 that has bitten into the sheet when a jam occurs in the punch member 101 or when an abnormality occurs in the drive motor M7. For this reason, the rotation operation member 106 is composed of a manual rotation knob connected to the rotation shaft 107 of the drive cam.

[0052] As shown in FIG. 5, the unit frame 102 includes an upper frame 102a having a predetermined length in a direction perpendicular to the sheet conveying direction of the straight path 28, and a lower frame 102b. A plurality of punch members 101a-101e are arranged on the upper frame 102a at predetermined intervals in a direction perpendicular to the sheet conveying direction (hereinafter referred to as the "conveyance perpendicular direction") so as to be reciprocable (vertically movable) in the punching direction. The lower frame 102b has punch holes (dies) formed in positions facing each punch unit 101. A drive shaft 107 is also arranged on the unit frame 102, and a drive cam is attached to the drive shaft 107 to move each punch member 101 up and down. A drive motor M7 is connected to the drive shaft 107 via a transmission mechanism.

[0053] The drive cam is composed of a cylindrical cam member that is axially attached to the drive rotation shaft 107 and corresponds to the multiple punch members 101, and each punch member is connected to this cam member by a connecting pin. The punch members 101 move up and down in the punching direction when the drive rotation shaft 107 rotates through a predetermined angle. At this time, a first group 101b and 101d of the multiple punch members (e.g., punching two holes) moves up and down in the punching direction at a first rotation angle of the drive rotation shaft 107, and a second group 101a, 101c and 101e (e.g., punching three holes) moves up and down in the punching direction at a different second rotation angle.

[0054] Therefore, the binding process control unit 95 described later controls the motor M7 to rotate the drive shaft 107 back and forth within a predetermined angle range, causing the punch members 101b and 101d of the first group to perform a punching motion, and to rotate the drive shaft 107 back and forth within a different angle range, causing the punch members 101a, 101c, and 101e of the second group to perform a punching motion.

[0055] The dust box 104 is disposed below the punch member 101, is supported by a guide rail (not shown) provided on the device frame, and is detachable from the front side of the device.

[0056] A drive motor M7 is connected to the drive rotation shaft 107 via a speed reduction mechanism (gear transmission mechanism), and the rotating member is placed on the front side of the side frame 70f through a hole provided in the side frame 70f so that the operator can rotate it manually. A front cover is placed on the front side of the device so that it can be opened and closed, and the rotation operation member 106 can be operated when the cover is open. Note that when the cover is open, no drive power is supplied (cut off) to the drive motor M7.

[0057] [Configuration of processing unit] Next, the configurations of the sheet carry-in mechanism, sheet positioning mechanism, binding mechanism, and sheet bundle carry-out mechanism of processing section B1 will be described.

[0058] <Sheet loading mechanism> As shown in Figure 3, between the straight path paper discharge outlet 35 and the processing tray 37, there are arranged a reversing conveying mechanism that switches back and conveys the sheet from the straight path paper discharge outlet 35 in the paper discharge direction and the opposite direction to the paper discharge direction, a guide mechanism (sheet guide member) 44 that guides the sheet toward the tray, and a pick-up rotor 46 that guides the sheet to the trailing end regulating section.

[0059] The reverse conveying mechanism is composed of a lifting roller 41 that moves up and down between an operating position where it engages with the sheet being transported onto the processing tray 37 and a separated standby position, and a paddle rotor 42 that transports the sheet in the opposite direction to paper discharge, and the lifting roller 41 and paddle rotor 42 are attached to a swinging bracket 43.

[0060] 1, a swing bracket 43 is arranged on the device frame 27 so as to be swingable about a rotation axis (for example, the paper discharge roller axis) shown in Fig. 3, and the rotation axes of the lift roller 41 and the paddle rotor 42 are bearing-supported on the swing bracket 43. An elevation motor (not shown) is connected to the swing bracket 43, and the swing bracket 43 moves the mounted lift roller 41 and paddle rotor 42 up and down between an operating position where they engage with the sheet and a standby position separated from the sheet.

[0061] A drive motor (not shown) is connected to the lift roller 41 and the paddle rotor 42, and drive is transmitted to rotate the lift roller 41 in forward and reverse directions and the paddle rotor 42 in the reverse direction (opposite the direction of paper discharge). The processing tray 37 is also provided with a driven roller 48 that is in pressure contact with the lift roller 41, and nips a single sheet or a stack of sheets to discharge them downstream.

[0062] A guide mechanism is disposed between the lift roller 41 and a take-in rotor 46 (described later) that guides the trailing edge of a sheet carried onto the processing tray 37 toward the sheet edge regulating unit 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, and the sheet guide member 44 retracts to the dotted line position when the sheet is discharged from the straight path paper discharge outlet 35, and guides the trailing edge of the sheet onto the processing tray 37 after the trailing edge of the sheet has passed through the straight path paper discharge outlet 35. For this reason, a drive mechanism (not shown) is connected to the sheet guide member 44, which moves up and down depending on the timing of guiding the trailing edge of the sheet from the straight path paper discharge outlet 35 onto the processing tray 37.

[0063] <Seat positioning mechanism> The processing tray 37 is provided with positioning mechanisms 38 and 39 for positioning sheets at a predetermined binding position, and the illustrated one includes a sheet end regulating section 38 that abuts and regulates the rear end of the sheet, and a side edge alignment section 39 that positions the side edge of the sheet at a reference position (center reference, one side reference).

[0064] The sheet end regulating section 38 is composed of a stopper member that abuts against and regulates the rear end of the sheet, as shown in Fig. 3. Also, the side edge aligning member 39, which will be described later in Fig. 9, ejects sheets from the straight path 28 based on the center, and depending on the type of binding mode, positions the sheets based on the same center or on one side.

[0065] <Side edge alignment mechanism> 9, side edge alignment plates 39F, 39R protrude upward from paper loading surface 37a of processing tray 37 shown in FIG. 3, have regulating surfaces 39x that engage with the side edges of sheets, and are arranged in a pair facing each other on the left and right. This pair of side edge alignment sections 39 is arranged on processing tray 37 so as to be able to move back and forth with a predetermined stroke. This stroke is set by the size difference between maximum size sheets and minimum size sheets and the offset amount by which the sheet stack is moved to the left or right (offset transport) after alignment.

[0066] In other words, the movement stroke of the left and right side edge alignment plates 39F, 39R is set by the movement amount for aligning sheets of different sizes and the offset amount of the sheet stack after alignment. When corner binding is performed, the side edge alignment plates 39F, 39R move the sheets fed out based on the center reference by a predetermined amount (offset movement) to the right for right-corner binding and to the left for left-corner binding. This offset movement can be performed one by one each time a sheet is fed into the processing tray 37 (for each fed-in sheet), or by moving the entire stack to perform binding after aligning the sheets into a stack.

[0067] 9, the side edge alignment section 39 is configured to include a right edge alignment member 39F (on the front side of the apparatus) and a left edge alignment member 39R (on the rear side of the apparatus), and both side edge alignment members have regulating surfaces 39x that engage with the side edges of sheets, which are supported on the processing tray 37 so as to move toward or away from each other. The processing tray 37 is provided with a slit groove (not shown) that penetrates from the front to the back, and the side edge alignment section 39, which has regulating surfaces 39x that engage with the side edges of sheets, is slidably fitted into this slit groove.

[0068] Each side edge alignment plate 39F, 39R is slidably supported on a plurality of guide rollers 80 (which may be rail members) on the rear side of the tray, and a rack 81 is integrally formed therewith. The left and right racks 81 are connected to alignment motors M1, M2 via pinions 82. The left and right alignment motors M1, M2 are composed of stepping motors, and are configured to detect the positions of the left and right side edge alignment plates 39F, 39R using position sensors (not shown), and to move each alignment member in either the left or right direction by a specified amount based on the detected value. Note that the illustrated rack-pinion mechanism is not limited to this, and each side edge alignment plate 39F, 39R may be fixed to a timing belt and connected via a pulley to a motor that reciprocates the timing belt left and right.

[0069] Furthermore, if the edges of the sheet conveyed onto the processing tray 37 droop, the corners of the sheet may come into contact with the slope of the processing tray 37, causing the leading edge of the sheet to move in the opposite direction of the conveyance along the slope of the processing tray 37, resulting in conveyance problems. Therefore, in a mode in which sheets are not placed on the processing tray 37, the side edge alignment members 39F, 39R may be moved inward of the sheet in the width direction of the conveyed sheet, and the top surfaces of the side edge alignment members 39F, 39R may support the sheet. In this embodiment, the modes in which sheets are not placed on the processing tray 37 refer to the "printout mode" and "jog sorting mode" described below. This lifts the leading edge of the conveyed sheet, thereby suppressing the amount of sheet droop. Note that this operation cannot be performed in jobs in which sheets are placed on the processing tray 37. For example, in the "staple binding processing mode" described below, if each side edge alignment member 39F, 39R is moved to the inside of the sheets being transported, the sheets already placed on the sheet stack will be pushed by each side edge alignment member 39F, 39R and become bent, and this mode cannot be implemented.

[0070] With the above configuration, the binding process control unit 95 (described later) causes the left and right side edge alignment members 39F and 39R to wait at predetermined standby positions (the sheet width size + α position) based on sheet size information provided by the image forming apparatus A. In the case of "multi-binding," sheets are fed onto the processing tray 37 shown in FIG. 3, and the alignment operation begins when the sheet edge strikes the sheet edge restriction unit 38. This alignment operation is performed by rotating the left and right alignment motors M1 and M2 shown in FIG. 9 by the same amount in opposite directions (approaching directions). The sheets fed into the processing tray 37 are then positioned based on the sheet center. By repeating this sheet feeding operation and alignment operation, the sheets are collated and stacked in a bundle on the processing tray 37. At this time, sheets of different sizes are positioned based on the center. In the case of "corner binding," sheets are fed onto the processing tray 37, and the alignment operation begins when the sheet edge strikes the sheet edge restriction unit 38. This alignment operation is performed by making the movement amount of the alignment plate on the binding position side different from that on the opposite side of the binding position, and the movement amount is set so that the sheet corner is positioned at a predetermined binding position.

[0071] <Binding processing mechanism> 3, a binding mechanism 47 is disposed which binds the sheet stack accumulated on the paper stacking surface 37a. The paper stacking surface 37a on the processing tray 37 is positioned at a predetermined binding position by a positioning mechanism (a sheet end regulating portion 38 and a side edge aligning portion 39). The binding mechanism 47 is configured as a binding unit 47 (hereinafter referred to as a "staple unit") which staples the sheet stack.

[0072] A binding processing mechanism 47 is arranged in the processing tray 37 to bind the rear end of the sheet conveyed from the straight path paper discharge outlet 35. The binding processing mechanism 47 is composed of a staple unit 47 that can be moved along the rear end of the paper carrying surface 37a of the processing tray 37, as shown in Figure 8.

[0073] 8 and 9 show the staple unit 47 arranged on the processing tray 37. In Fig. 9, the binding position Cp1 is set at the sheet corner located on the left side of the drawing. The staple unit 47 moves at a predetermined stroke SL1 along a first traveling rail 53 and a second traveling rail 54 formed on the device frame 27b.

[0074] 9 shows sheets fed into the processing tray 37 and the movement stroke SL1 of the binding unit 47. Sheets of different sizes, from the largest size sheet to the smallest size sheet, are fed into the processing tray 37 with the center as the reference. A pair of left and right side edge alignment plates 39F, 39R aligns these sheets so that sheets of different sizes coincide with each other, using the binding edge of the sheet (the left edge in the illustrated example) as the reference. Therefore, the left and right side edge alignment plates 39F, 39R are connected to different drive motors M1, M2, respectively, and a binding process control unit 95, described later, sets the movement amount of the left and right side edge alignment plates 39F, 39R according to the sheet size.

[0075] In addition, the binding process control unit 95, which will be described later, aligns the sheets based on the center reference in the binding process other than the binding process at the sheet corners, for example, in the multi-binding mode, which will be described later. In this case, the left and right side edge alignment plates 39F, 39R position the sheets at the binding position by moving the same amount from the standby position toward the sheet center.

[0076] 9, the binding unit 47 moves a stroke SL1 between a standby position Wp1 (first standby position) and the binding position Cp1. That is, the binding unit 47 moves back and forth between the standby position Wp1 and the binding position Cp1 along traveling rails 53 and 54 (guide grooves, guide rods, etc.). The first standby position Wp1 is set outside the maximum size sheets to be bound on the processing tray 37.

[0077] Fig. 10 shows the configuration of the binding unit 47. A pair of left and right pulleys 58a, 58b are arranged on the device frame 27b along the movement area (left and right direction in Fig. 9) of the staple unit 47, a timing belt 59 (toothed belt) is stretched between the two pulleys, and a drive motor M3 (stepping motor) is connected to one of the pulleys, 58a.

[0078] <Staple moving mechanism> As shown in Fig. 8, the staple unit 47 is mounted so as to be movable at a predetermined stroke on a device frame (chassis frame) 27b which is fixed to the side frames 70f, 70r by passing through an opening provided in the side frame 70f of the device frame 70. A first traveling rail 53 and a second traveling rail 54 are arranged on the device frame 27b. A traveling rail surface 53x is formed on the first traveling rail 53, and a traveling cam surface 54x is formed on the second traveling rail 54. The traveling rail surface 53x and the traveling cam surface 54x cooperate with each other to support the staple unit 47 (hereinafter referred to as "moving unit" in this section) so as to be movable back and forth at a predetermined stroke, and at the same time, control its angular posture.

[0079] The first traveling rail 53 and the second traveling rail 54 are formed with rail surfaces 53x and traveling cam surfaces 54x so as to reciprocate within the movement range of the moving unit. As shown in Fig. 10, a timing belt 59 connected to a drive motor (travel motor) M3 is fixed to the staple unit 47. The timing belt 59 is wound around a pair of pulleys 58a, 58b journaled on the device frame 27b, and the drive motor M3 is connected to one of the pulleys. Therefore, when the drive motor M3 rotates forward or backward, the staple unit 47 reciprocates with a stroke SL1.

[0080] The staple unit 47 engages with the first and second traveling rails 53, 54 as follows. As shown in Fig. 8, the staple unit 47 is provided with first rolling rollers 83 (rail fitting members) that engage with the traveling rail surfaces 53x and second rolling rollers 84 (cam follower members) that engage with the traveling cam surfaces 54x. The staple unit 47 is also formed with ball-shaped sliding rollers 47x (two rollers shown) that engage with the support surfaces of the frame 27b. The staple unit 47 is also formed with guide rollers 47y that engage with the bottom surface of the bottom frame, thereby preventing the staple unit 47 from floating up from the device frame 27b.

[0081] With the above-described configuration, the staple unit 47 is movably supported by the device frame 27b with the sliding rollers 47x and the guide rollers 47y. The first rolling rollers 83 and the second rolling rollers 84 rotate along the traveling rail surface 53x and the traveling cam surface 54x, respectively, while following the rail surface 53x and the cam surface 54x.

[0082] <Stack tray lifting mechanism> As shown in Fig. 11, the sheet post-processing device B is equipped with a first tray 49. The first tray 49 is configured to be raised and lowered according to the amount of sheets stacked thereon. For this purpose, guide rollers 85 are provided at two locations, one above the other, at the base end of the first tray 49, and the guide rollers 85 are fitted and supported by lift guides 86 provided on the device frame 27. A lift gear 88 is provided at the base end of the first tray 49 and is connected to a lift rack gear 87. A lift motor M4 is also connected to the lift gear 88. Therefore, by controlling the rotation of the lift motor M4, the first tray 49 is raised and lowered according to the amount of sheets stacked thereon.

[0083] <Sheet bundle discharge mechanism> A sheet bundle discharge mechanism is disposed on the processing tray 37, which discharges the bound sheet bundle toward the downstream first tray 49. Known configurations for transporting the sheet bundle downstream include a method in which a pair of rollers press against each other (discharge roller mechanism), and a conveyor mechanism in which a pusher member moves from upstream to downstream along the tray surface to push out the trailing ends of the sheets. The illustrated device employs both of these mechanisms.

[0084] 12 shows the sheet bundle discharge mechanism. The conveyor mechanism includes a push-out protrusion 45 that transfers the sheets from a binding position (processing position) located upstream along the processing tray 37 to a stack tray (first tray) 49 located downstream, a conveyor belt 45v that moves the push-out protrusion, and a drive motor M6. A driven roller 48 is disposed at the discharge outlet (the boundary between the paper loading surface 37a and the first tray 49) of the processing tray 37, and a lift roller 41 that presses against the driven roller 48 is disposed opposite the driven roller 48, and the driven roller 48 and the lift roller 41 form a discharge roller mechanism.

[0085] Therefore, the processing tray 37 is provided with conveyor mechanisms 45, 45v that transport the sheet bundle by pushing it from the upstream side to the downstream side, and discharge roller mechanisms 48, 41 that nip and discharge the sheet bundle. FIG. 12(a) shows a state in which the sheet bundle is positioned at the binding position on the processing tray 37. At this time, the conveyor mechanisms 45, 45v and the discharge roller mechanisms 48, 41 are in operation. FIG. 12(b) shows a state in which the sheet bundle is being transported from the processing position to the downstream side, where the sheet bundle is sent downstream by the movement of the push-out protrusion 45 and the rotation of the discharge roller mechanisms 48, 41. FIG. 12(c) shows a state immediately before the sheet bundle is discharged to the first tray 49 on the downstream side, where the sheet bundle is gradually (slowly) sent downstream on the processing tray by the rotation of the discharge roller mechanisms 48, 41. At this time, the push-out protrusion 45 waits in the illustrated position and returns (rearwards) to its initial position.

[0086] <Configuration of the staple unit> The configuration of the above-mentioned staple unit will be described with reference to Fig. 13. The staple unit 47 is configured as a unit separate 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 that rotates the drive cam 47d are mounted on the unit frame 47a.

[0087] The staple head 47b and the anvil member 47c are arranged on the drive cam 47d to face each other at the stapling position, and the staple head 47b is biased by a biasing spring (not shown) on the drive cam 47d from an upper standby position to a lower staple position (anvil member) to move up and down. A staple cartridge 52 is detachably mounted on the unit frame 47a.

[0088] The staple cartridge 52 stores straight blank staples, and a staple feed mechanism supplies the staples to the staple head 47b. The staple head 47b contains a former that bends the straight staples into a U-shape and a driver that presses the bent staples into a sheet stack. With this configuration, the drive motor M4 rotates the drive cam 47d, storing energy in the spring. When the rotation angle reaches a predetermined angle, the staple head 47b swiftly descends toward the anvil member 47c. This action bends the staple into a U-shape, and the driver then inserts the staples into the sheet stack. The tip of the staple is then bent by the anvil member 47c, resulting in staple binding.

[0089] A staple feed mechanism is built in between the staple cartridge 52 and the staple head 47b, and a sensor (empty sensor) is disposed in the staple feed mechanism to detect when there are no staples. Also, a cartridge sensor (not shown) is disposed in the unit frame 47a to detect whether the staple cartridge 52 is inserted or not.

[0090] The staple cartridge 52 employs a structure in which staples connected in a band-like shape are stored in a box-shaped cartridge in layers, or in a roll-like structure. Furthermore, the unit frame 47a is provided with circuits for controlling the above-mentioned 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 staples are empty. Furthermore, the staple control circuit controls the drive motor M4 to execute the stapling operation in response to a staple signal, and is configured to issue an "operation end signal" when the staple head portion 47b moves from the standby position to the stapling position and then returns to the standby position.

[0091] <Control configuration explanation> The control configuration of the image forming system in Fig. 1 will be described with reference to Fig. 14. The image forming system shown in Fig. 14 includes a control unit 90 of image forming apparatus A (hereinafter referred to as "main body control unit") and a control unit 95 of sheet post-processing apparatus B (hereinafter referred to as "binding process control unit"). 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).

[0092] Then, the "image formation mode" and "post-processing mode" are set based on user operations received via the input unit 93 (control panel). In the image formation mode, for example, mode settings such as color / monochrome printing, double-sided / single-sided printing, and image formation conditions such as sheet size, sheet paper quality, number of printouts, enlarged / reduced printing, etc. are set. In the "post-processing mode," for example, "printout mode," "bookbinding processing paper output mode," "staple binding processing mode," and "jog sorting mode" are set.

[0093] The main body control unit 90 also transfers data such as the setting of the post-processing mode, the number of sheets, the number of copies, and the thickness of the sheets on which images are 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 every time image formation is completed.

[0094] The post-processing mode will now be described. The "printout mode" is a mode in which sheets from the straight path paper discharge port 35 are stored in the first tray 49 without being bound. In this case, the sheets are not placed on the processing tray 37, but are transported by the paper discharge roller 36, the lift roller 41, and the driven roller 48 to the first tray 49 and stacked thereon.

[0095] The "product processing paper discharge mode" is a mode in which sheets from the straight path paper discharge outlet 35 are transported to the saddle section B2, and the sheets on which images are formed are collated, bound, and then folded to complete the bookbinding process.

[0096] The "staple binding processing mode" is a mode in which sheets from the straight path paper discharge outlet 35 are placed on the processing tray 37 and collated, and after this sheet stack is bound, it is stored in the first tray 49. In this case, the operator specifies that the sheets on which images are to be formed are, in principle, sheets of the same paper thickness and size. In this staple binding processing mode, one of "multi-binding," "right corner binding," or "left corner binding" is selected and specified.

[0097] In the "jog sorting mode," sheets with images formed on them by the image forming apparatus A are separated into groups that are offset and stacked, and groups that are stacked without offset. The first tray 49 alternately stacks the offset-shifted and non-offset-shifted sheet bundles. In this embodiment, this offset shifting is performed by shifting the sheets by a predetermined amount toward or away from the first conveyance roller 201, the second conveyance roller 202, and the third conveyance roller 203 while conveying the sheets in sequence. During this shifting, the discharge roller 36 is separated from the processing tray 37 so as not to interfere with the shifting. After the shifting, the "jog sorting mode" does not place sheets on the processing tray 37. Instead, the already shifted sheets are nipped by the discharge roller 36, the lift roller 41, and the driven roller 48, and are transported to the first tray 49 for stacking.

[0098] <Binding process control section> The binding process control unit 95 operates the sheet post-processing device B in accordance with the post-processing mode set by the image formation control unit 90. The binding process control unit 95 includes a control CPU. A ROM 96 and a RAM 97 are connected to the binding process control unit 95, and the operation of the sheet post-processing device B in this 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 binding process control unit 95 controls the drive circuits of all the drive motors mentioned above, and starts, stops, and controls the forward and reverse rotation of each motor.

[0099] <Sheet loading mechanism> The stiffening member in this embodiment will be described with reference to Figure 15. A pre-processing transport lower guide 78 and a pre-processing transport upper guide 79 are provided near the discharge rollers 36 as part of the straight path 28 in Figure 3. Stiffening members 72 are arranged between the lower discharge rollers 36b at the straight path discharge outlet 35, and on either side of the lower discharge rollers 36b in the sheet width direction.

[0100] 16 is a cross-sectional view showing the positional relationship between the stiffening member 72 and the discharge roller 36. The stiffening member 72 is arranged to support the sheet at a higher position than the sheet supported by the pre-processing transport lower guide 78. The stiffening member 72 is supported by a stiffening member holder 73 arranged on the back side of the pre-processing transport lower guide 78, where the pre-processing transport lower guide 78 does not come into contact with the sheet. The stiffening member 72 may also be arranged to support the sheet at a higher position than the nip point of the discharge roller 36. This allows the sheet supported by the pre-processing stiffening lever 72 to have less contact with the lower discharge roller 36b when the discharge roller 36 is separated from the pre-processing transport lower guide 78.

[0101] Next, the function of the stiffening member 72 will be described using FIG. 17 . FIG. 17 is a schematic diagram of the discharge rollers 36 viewed from the straight-path discharge outlet 35 in the sheet transport direction. In this embodiment, the stiffening member 72 is disposed between the lower discharge rollers 36b and sandwiched between the lower discharge rollers 36b in the sheet width direction. The stiffening member 72 supports the sheet S conveyed by the conveyance rollers 36 at a position inward of the sheet by a predetermined distance L extending from both edges in the sheet width direction, thereby reducing the angle θ at which the sheet sags under its own weight. This effectively prevents conveyance problems that occur when a corner of the sheet contacts the slope of the processing tray 37 shown in FIG. 3 and moves along the slope in the opposite direction to the conveyance direction. Note that this predetermined distance L is designed to minimize the number of stiffening members required based on the width of the sheet that can be conveyed, while still minimizing the amount of sheet edge sagging and preventing conveyance problems.

[0102] Figure 18 shows the configuration of the stiffening member 72. The stiffening member 72 has a rotating shaft 76 and is supported by a stiffening member holder 73. The conveying direction inclined surface 72b is inclined so that the sheet can be conveyed in the sheet conveying direction. The moving inclined surface 72a and the curved surface 72c connecting the moving inclined surface 72a and the conveying direction inclined surface 72b are designed so that the sheet can be conveyed in the sheet width direction, as will be described in detail later. To maintain the position of the stiffening member 72, the stiffening member spring 74 is attached to the stiffening member 72 and the pre-processing stiffening lever holder 73, engaging with them downstream of the rotating shaft 76 in the conveying direction. This allows the stiffening member 72 to move vertically downward due to the weight of the sheet when the sheet being conveyed by the discharge rollers 36 is stiff, thereby preventing the sheet from being impeded in conveying. After the sheet has passed, the stiffening member spring 74 returns the member to its original position. At this time, a cushion 75 may be provided so as to protrude beyond the mechanical stopper in order to suppress the collision noise between the stiffening member spring 74 returning to its original position and the mechanical stopper of the pre-processing stiffening lever holder 73. Note that the stiffening member spring 74 may also be attached so as to engage with the stiffening member 72 and the pre-processing conveyance lower guide 78 on the upstream side of the rotation shaft 76 in the conveyance direction, so that the stiffening member 72 is pushed by the sheet's own weight and moves vertically downward.

[0103] Next, a case where the shape of the stiffening member 72 functions will be described based on this embodiment. FIG. 19 illustrates a case where a sheet LS is conveyed to the straight path 28 and moved a predetermined distance toward either the front or rear in the "jog sorting mode." In the "jog sorting mode," the first conveyance roller 201, the second conveyance roller 202, and the third conveyance roller 203 sequentially convey the sheet while moving the sheet a predetermined distance in the sheet width direction, thereby offsetting the sheet LS in the sheet width direction. In this embodiment, the offset movement in the sheet width direction begins after the trailing edge of the sheet LS in the sheet conveyance direction passes the straight path entrance 26. The offset movement in the sheet width direction ends when the trailing edge of the sheet LS passes the first conveyance roller 201. Therefore, if the length of the sheet LS is longer than the length of the straight path 28 from the first conveyance roller 201 to the discharge roller 36, there is a risk that the leading edge of the sheet LS will pass the discharge roller 36 and reach the stiffening member 72 before the offset movement in the sheet width direction ends.

[0104] When the leading edge of the sheet LS reaches the stiffening member 72, as shown in FIG. 20 , depending on the width of the sheet LS, the sheet LS may be offset in the sheet width direction, causing the edge of the sheet LS relative to the sheet width direction to come into contact with the stiffening member 72 from the sheet width direction. For example, in this embodiment, when a B4-sized sheet is offset 10 mm toward the rear, the edge of the sheet LS relative to the sheet width direction comes into contact with the stiffening member 72 from the sheet width direction. In this case, with the shape of the conventional stiffening member 72, even if the sheet edge at the contacting point attempts to move in the sheet width direction, the movement is stopped by the stiffening member 72. The edge of the sheet that cannot move passes through the first conveyor roller 201, the second conveyor roller 202, and the third conveyor roller 203, the deflection is eliminated, and the sheet is pushed back to the stiffening member. This may prevent the sheet from being offset in the sheet width direction.

[0105] To solve this problem, in this embodiment, the stiffening member 72 is shaped to enable offset movement of the sheet in the sheet width direction. The movement slope 72a in FIG. 18 is provided with a slope in the vertical direction so as to enable offset movement of the sheet in the sheet width direction. In addition, by inclining the movement slope 72a with respect to the sheet width direction, the shape is such that the contact area between the sheet moving in the sheet width direction and the stiffening member 72 increases as the sheet moves in the sheet width direction. Furthermore, the movement slope 72a and the conveyance direction slope 72b are connected by a curved surface 72c formed so as to enable offset movement of the sheet in the sheet width direction.

[0106] As described above, in this embodiment, the shape of the stiffening member 72 enables the sheet to move without being hindered by the stiffening member 72 when the sheet is offset in the sheet width direction by the first conveyance roller 201, the second conveyance roller 202, and the third conveyance roller 203. The stiffening member 72 shown in FIG. 18 has a shape in which the movement inclined surfaces 72a are arranged symmetrically with respect to the conveyance direction inclined surfaces 72b. However, even if the shapes are not symmetrically arranged as in this embodiment, a similar effect can be obtained as long as the shape does not hinder the movement of the sheet when it is offset in the sheet width direction. Furthermore, the movement inclined surfaces 72a may have a recess or a hole formed therein as long as the shape does not hinder the movement of the sheet when it is offset in the sheet width direction.

[0107] Although this embodiment is performed using the sheet post-processing device B, an image forming system equipped with the image forming device A and the sheet post-processing device B can also achieve the effect of allowing the sheet to be offset in the sheet width direction by the first conveying roller 201, the second conveying roller 202, and the third conveying roller 203. [Explanation of symbols]

[0108] B: Sheet post-processing device / 26: Straight path entrance / 28: Straight path / 35: Straight path paper exit / 36: Paper exit roller (transport roller) / 37: Processing tray (loading tray) / 39F, 39R: Side edge alignment plate / M1, M2: Drive motor / 41: Lifting roller / 47: Binding unit (stapler) / 72: Stiffening member / 78: Pre-processing transport lower guide (support member) / 201: First transport roller (shift roller) / 202: Second transport roller (shift roller) / 203: Third transport roller (shift roller)

Claims

1. a shift roller that conveys the sheet in a predetermined conveying direction and moves the sheet a predetermined distance in a sheet width direction that is a direction intersecting the predetermined conveying direction; a conveying roller that is in a nip state where the shift roller pinches a surface of the sheet conveyed by the shift roller to convey the sheet in the predetermined conveying direction, and a separation state where the shift roller separates from the surface of the sheet conveyed by the shift roller from when the sheet starts to move a predetermined distance in the sheet width direction by the shift roller until the movement ends; a support member for supporting the sheet conveyed by the conveying roller; a loading tray disposed below the first transport roller and configured to load the sheet transported by the first transport roller; a stapler capable of binding a sheet bundle formed of a plurality of sheets placed on the loading tray; a stiffening member that provides a sheet conveyed in the predetermined conveying direction by the conveying rollers in the nipped state with a conveying direction inclined surface that allows the sheet to be conveyed in the predetermined conveying direction, the stiffening member being disposed at a position inside the sheet by a predetermined distance extending in the sheet width direction from both end edges in the sheet width direction of the sheet conveyed by the conveying rollers, and supporting the sheet at a position higher than the support member; The stiffening member is provided with a moving direction inclined surface that allows one edge of the sheet to move a predetermined distance in the sheet width direction when the sheet moves a predetermined distance in the sheet width direction by the shift rollers and the shift rollers move the predetermined distance in the sheet width direction and the sheet finishes moving.

2. 2. The sheet processing apparatus according to claim 1, wherein the stiffening member has a movement direction inclined surface that is inclined with respect to the sheet width direction.

3. 3. The sheet processing apparatus according to claim 1, wherein the stiffening member connects the conveying direction inclined surface and the moving direction inclined surface with a curved surface that allows one edge of the sheet in the sheet width direction of the sheet moved a predetermined distance in the sheet width direction by the shift roller to move a predetermined distance in the sheet width direction.

Images