Sheet processing device, image forming system

Abstract

In a jam sheet removal configuration in which multiple roller pairs can separate at once, the positioning reference when the multiple roller pairs are nipped again after the jam sheet has been removed is set closer to the forward and reverse conveying rollers than to the rollers that convey in only one direction, thereby providing a sheet processing device that suppresses the tilting of the forward and reverse conveying rollers. [Solution] The sheet processing device includes a positioning unit that positions the mechanism before it is fixed by a fixing latch when the first roller comes into contact with the second roller and the third roller comes into contact with the fourth roller, and the positioning unit is located closer to the second transport position than to the first transport position.

Description

Technical Field

[0001] The present invention relates to a sheet processing apparatus that performs processing on an image-formed sheet, and an image forming system.

Background Art

[0002] An image forming system that performs post-processing on sheets is known, which is a system including an image forming apparatus and a post-processing apparatus connected to a sheet discharge port of the image forming apparatus, that accumulates the image-formed sheets, performs post-processing thereon, and stacks the sheets on a stacking unit.

[0003] Patent Document 1 describes that when clearing a jam that has occurred in a post-processing unit, the entire front cover of the post-processing unit can be pulled out to the front side, so that only one operation of pulling the front cover is required when pulling out the processing unit, and the operability can be improved.

[0004] As described above, when removing a jammed sheet in the post-processing apparatus, it is desired that the jammed sheet can be removed by a single operation, and it is preferable that a plurality of conveying rollers are separated at the same time for a sheet conveying path or the like.

[0005] However, when separating a plurality of rollers at the same time, rollers that perform not only normal rotation conveyance but also reverse rotation conveyance must also be separated, and it is necessary to suppress displacement of the reverse rotation conveying rollers that require high accuracy.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0007] The present invention aims to provide a sheet processing apparatus and an image forming apparatus that suppress the tilting of forward and reverse conveying rollers by setting the positioning reference when the multiple roller pairs are nipped again after the jam sheet has been removed, closer to the forward and reverse conveying rollers than to the rollers that convey in only one direction. [Means for solving the problem]

[0008] The sheet processing apparatus according to the present invention includes a transport path through which sheets are transported from an inlet to an outlet; a first roller and a second roller that transport the sheets received from the inlet toward the outlet at a first transport position; a third roller and a fourth roller that transport the sheets transported by the first roller and the second roller toward the outlet at a second transport position; a branch path that branches off from the transport path and through which sheets are fed by the third roller and the fourth roller transporting the sheets toward the inlet; a folding processing unit that performs folding on the sheets in the branch path; and a sheet that remains in the transport path. The device is characterized by comprising: a mechanism that separates the first roller from the second roller and the third roller from the fourth roller so that an operator can access it from the front of the device; a fixing latch that fixes the mechanism so that the first roller and the second roller are in contact and the third roller and the fourth roller are in contact; and a positioning unit that positions the mechanism before it is fixed by the fixing latch when the mechanism brings the first roller into contact with the second roller and the third roller into contact with the fourth roller, wherein the positioning unit is located closer to the second transport position than to the first transport position. [Effects of the Invention]

[0009] According to the present invention, in a jam sheet removal configuration in which multiple pairs of rollers, including forward and reverse conveying rollers, can be separated at once, the tilt of the forward and reverse conveying rollers is suppressed when the multiple pairs of rollers are nipped again after the jam sheet has been removed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram showing the external appearance of an image forming system. [Figure 2] This is a diagram showing the configuration of a sheet post-processing apparatus. [Figure 3] This is a diagram showing the configuration in the vicinity of a straight path. [Figure 4] This is a diagram showing the configuration of a punch unit. [Figure 5] This is a diagram showing the configuration of a punch unit. [Figure 6] This is a diagram for explaining a shift mechanism of a conveyance roller. [Figure 7] This is a diagram for explaining a shift mechanism of a conveyance roller. [Figure 8] This is a diagram for explaining a binding processing mechanism. [Figure 9] This is a diagram for explaining a binding processing mechanism. [Figure 10] This is a diagram for explaining a binding processing mechanism. [Figure 11] This is a diagram for explaining a tray lifting and lowering mechanism. [Figure 12] This is a diagram for explaining a sheet discharge mechanism. [Figure 13] This is a diagram showing the configuration of a staple unit. [Figure 14] This is a diagram showing the configuration around a control unit. [Figure 15] This is a flowchart showing processing of a bookbinding processing sheet discharge mode. [Figure 16] This is a diagram for explaining a sheet buffer operation in a sheet processing apparatus. [Figure 17] This is a diagram for explaining a sheet buffer operation in a sheet processing apparatus. [Figure 18] This is a diagram for explaining a sheet buffer operation in a sheet processing apparatus. [Figure 19] This is a diagram for explaining a sheet buffer operation in a sheet processing apparatus. [Figure 20] This is a diagram for explaining a sheet buffer operation in a sheet processing apparatus. [Figure 21] This is a diagram for explaining the sheet buffer operation in the sheet processing apparatus. [Figure 22] This is a diagram for explaining the sheet buffer operation in the sheet processing apparatus. [Figure 23] This is a diagram for explaining the sheet buffer operation in the sheet processing apparatus. [Figure 24] This is a diagram for explaining lateral registration adjustment. [Figure 25] This is a diagram for explaining lateral registration adjustment. [Figure 26] This is a diagram for explaining lateral registration adjustment. [Figure 27] This is a diagram for explaining lateral registration adjustment. [Figure 28] This is a diagram for explaining lateral registration adjustment. [Figure 29] This is a diagram for explaining lateral registration adjustment. [Figure 30] This is a diagram for explaining lateral registration adjustment. [Figure 31] This is a diagram for explaining lateral registration adjustment. [Figure 32] This is a diagram for explaining lateral registration adjustment. [Figure 33] This is a diagram for explaining lateral registration adjustment. [Figure 34] This is a flowchart illustrating the sheet buffer operation. [Figure 35] This is a flowchart illustrating the sheet buffer operation. [Figure 36] This is a diagram for explaining the operation in the case of a large-sized sheet. [Figure 37] This is a diagram for explaining the operation in the case of a large-sized sheet. [Figure 38] This is a diagram for explaining the operation in the case of a large-sized sheet. [Figure 39] This is a diagram for explaining the operation in the case of a large-sized sheet. [Figure 40] This is a diagram for explaining another embodiment. [Figure 41] This is a diagram illustrating another embodiment. [Figure 42] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 43] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 44] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 45] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 46] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 47] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 48] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 49] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 50] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 51] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 52] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 53] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 54] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 55] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 56] This is a diagram illustrating the configuration for removing jammed sheets. [Figure 57] This is a diagram illustrating the configuration for removing jammed sheets. [Modes for carrying out the invention]

[0011] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0012] [Image forming apparatus] The image forming apparatus A in the image forming system shown in Figure 1 will be described. The illustrated image forming apparatus A represents an electrostatic printing mechanism and consists 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 a mounting surface (e.g., the floor). Inside the apparatus housing 1 are a paper feeding unit 2, an image forming unit 3, a paper discharge unit 4, and a data processing unit 5.

[0013] The paper feeding unit 2 includes cassette mechanisms 2a to 2c for storing sheets of multiple sizes for image formation, and the main control unit 90 feeds sheets of a specified size into the paper feeding path 6. For this purpose, multiple cassettes 2a to 2c are detachably arranged in the device housing 1, and each cassette has a separation mechanism for separating the sheets inside one by one and a paper feeding mechanism for feeding the sheets. The paper feeding path 6 is provided with transport rollers 7 for feeding the sheets supplied from the multiple cassettes 2a to 2c to the downstream side, and a pair of registration rollers 8 is provided at the end of the path to align the leading edge of each sheet.

[0014] Furthermore, the paper feed path 6 is connected to a high-capacity cassette 2d and a manual feed tray 2e. The high-capacity cassette 2d includes an optional unit for storing sheets of sizes that are consumed in large quantities, and the manual feed tray 2e is configured to supply special sheets such as thick paper sheets, coated sheets, and film sheets that are difficult to feed separately.

[0015] The image forming unit 3 is shown as an example of an electrostatic printing mechanism, and a photoreceptor 9 (drum, belt), an emitter 10 that emits an optical beam onto the photoreceptor 9, a developer 11, and a cleaner (not shown) are arranged around the rotating photoreceptor. The diagram shows a monochrome printing mechanism, in which a latent image is optically formed on the photoreceptor drum 9 by the emitter 10, and toner ink is applied to this latent image by the developer 11. Then, in time with the image formation on the photoreceptor 9, a sheet is sent from the paper feed path 6 to the image forming unit 3, the image is transferred onto the sheet by the transfer charger 12, and fixed by the fixing unit (roller) 13 located in the paper discharge path 14. The paper discharge path 14 has a paper discharge roller 15 and a paper discharge port 16, and transports the sheet to the sheet post-processing device B, which will be described later.

[0016] The scanner unit A2 consists of a platen 17 on which the image document 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 the reflected light from the document on the platen 17 to the photoelectric conversion unit 19. Figure 21 shows the second platen (traveling platen), which reads images from the sheet sent from the feeder unit A3 using the carriage 18 and the 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 sheets sent from the paper feed tray to the traveling platen 21, and an output tray 24 that stores the originals for which images have been read by the platen.

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

[0019] [Sheet Post-Processing Device] The sheet post-processing device B is a device that processes sheets discharged from the paper output port 16 of the image forming apparatus A and includes, for example, (1) a function for stacking and storing the image-formed sheets (printout mode), (2) a function for dividing and storing the image-formed sheets (jog sorting mode), (3) a function for aligning and stacking the image-formed sheets and binding them (binding mode), and (4) a function for folding the image-formed sheets after they have been aligned and bound to finish them as a book (bookbinding mode).

[0020] In this embodiment, the sheet post-processing device B does not need to have all of the above functions, and is configured as appropriate according to the device specifications (design specifications). In this embodiment, as an example, it is assumed that the device has the function of aligning and binding the image-formed sheets, then folding them to finish the book.

[0021] Figure 2 shows the configuration of the sheet post-processing device B, and Figure 3 shows the configuration around the straight path 28. The sheet post-processing device B processes the sheets fed in from the straight path inlet 26 connected to the paper output slot 16 of the image forming apparatus A, and then stores them in the storage section (the first stack tray 49, second stack tray 61, and third stack tray 71, described later). The illustrated device transfers the sheets sent to the straight path 28 from the processing unit B1, which includes 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"). It also transfers the sheets sent to the straight path 28 from the saddle section 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 shape, it can also transport cardboard and the like.

[0022] Processing unit B1 is located at the exit of the straight path 28 (straight path paper output 35) and aligns and stacks the sheets as they are fed sequentially, performs binding, and then stores them in the first tray 49. Saddle unit B2 is located at the exit of the saddle path 32, which branches off from the straight path 28 (saddle path paper output 35) and is a post-processing unit that aligns and stacks the sheets as they are fed sequentially, performs saddle stitching (or sometimes saddle stitching), folds them, and stores them in the second tray 61. The following describes each component in detail.

[0023] <Device Housing> As shown in Figure 2, the sheet post-processing device B comprises a device housing 27, a straight path 28 built inside the device housing and having a straight path inlet 26 and a straight path output port 35, a processing unit B1 and a saddle unit B2 for post-processing sheets sent from the straight path 28, and a first tray 49, a second tray 61, and a third tray 71 for storing sheets sent from each post-processing unit. The illustrated device housing 27 is positioned at approximately the same height as the housing 1 of the image forming apparatus A located upstream, and the output port 16 of the image forming apparatus A and the straight path inlet 26 of the sheet post-processing device B are connected on the installation surface.

[0024] The housing 27 of the seat aftertreatment device includes a device frame 70. The device frame 70 forms the framework of a box-shaped device, for example, as shown in Figure 6, and includes a front side frame 70f located at the front in the state shown in Figure 1, a rear side frame 70r located at the back, and a stay member (connecting reinforcing member) that connects the two side frame frames. The straight path 28, processing unit B1, saddle section B2, etc., which will be described later, are attached between these left and right side frame frames. The device housing 27 is not limited to the shape shown and can be designed in a form that is suitable for the design, and the device frame 70 is not limited to a left and right side frame and connecting stay structure, but can also be a monocoque structure or various other frame structures.

[0025] <Sheet delivery route> As shown in Figure 3, the straight path 28 is a substantially straight path that crosses the device housing 27 in a substantially horizontal direction and includes a straight path inlet 26 connected to the paper output port (main paper output port) 16 of the image forming apparatus A, and a straight path paper output port 35 located on the opposite side across the device from this inlet (straight path inlet 26). The straight path 28 has a transport mechanism that enables sheet transport from the straight path inlet 26 to the straight path paper output port 35 and from the straight path paper output port 35 to the straight path inlet 26, and the inlet roller 29, first transport roller 201, second transport roller 202, and third transport roller 203 are arranged in that order from the straight path inlet 26 side. The straight path paper output port 35 also has a transport mechanism, which includes a paper output roller 36 (including a sheet transport mechanism such as a belt). Furthermore, near the straight path inlet 26, an inlet sensor Se1 is positioned to detect either the leading or trailing end of the sheet to be received, or both, and a lateral register detection sensor S0 (detection unit) is positioned to detect the end face position (side edge) parallel to the sheet's transport direction. Also, near the straight path output port 35, an output sensor Se2 is positioned to detect the leading or trailing end of the sheet. Sheets discharged from the straight path output port 35 are either discharged to the first tray 49 via the first output path 31 connected to the straight path output port 35, or guided to the processing unit B1. A punch unit 100 for punching holes in the sheet is also positioned on the straight path 28. The inlet sensor Se1 and output sensor Se2 can employ a photo interrupter or a system combining a flag that contacts the sheet with a sensor.

[0026] <Layout of the sheet delivery route> As shown in Figures 2 and 3, the straight path 28 has the following paths arranged in the order of "saddle path 32," "saddle buffer path P2," "processing buffer path P1," and "upper transport path 30" from the straight path inlet 26 to the straight path output port 35. At the branching points between each of these paths, a transport switching mechanism (branching mechanism) for the transported sheets is provided, consisting of a saddle path flapper 33b, a saddle buffer path flapper 33a, a processing buffer path flapper 200, and an upper transport path flapper 34. In this embodiment, the saddle buffer path P2 and the upper transport path 30 are configured as retraction paths for retracting sheets. Also, as shown in Figure 2, a saddle section B2 is provided on one side of the straight path 28, and the saddle buffer path P2 and upper transport path 30 are provided on the opposite side (the other side). This makes it possible to further improve the transport efficiency of sheets located in the retraction path to the saddle section B2.

[0027] In each of the above paths, the saddle path 32, the saddle buffer path P2, and the processing buffer path P1 are configured as switchback paths that transport the sheet in the opposite direction to the transport direction from the straight path inlet 26 to the straight path output port 35 and feed it into each of the above paths. The upper transport path 30 is configured to feed the sheet by transporting it in the same direction as the transport direction from the straight path inlet 26 to the straight path output port 35.

[0028] <Path branching mechanism> The saddle path flapper 33b, saddle buffer path flapper 33a, and processing buffer path flapper 200, which are branching mechanisms for the sheet described above, are composed of movable flapper guides that can switch the transport path of the sheet fed in from the straight path inlet 26, and are connected to drive mechanisms (not shown) such as electromagnetic solenoids and mini-motors. The 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 buffer flapper 200 guides the sheet sent from the straight path inlet 26 to the processing buffer path P1 via processing buffer rollers 301a and 301b. The upper transport path flapper 34 includes a movable flapper guide that switches the transport path so that the sheet fed from the straight path inlet 26 is transported to either the straight path paper output port 35 or the upper transport path 30, and is connected to a drive mechanism (not shown) such as an electromagnetic solenoid or a mini-motor.

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

[0030] <Saddle Pass> A saddle path 32 is connected to the straight path 28 for transporting sheets to the saddle section B2, and a saddle path flapper 33b is provided at the path branching point to guide the sheets to the saddle path 32. Sheets guided from the saddle path 32 through the saddle path output slot to the saddle section B2 are saddle-stitched and folded, and then discharged to the second tray 61 via a roughly horizontal saddle discharge path 68. It is preferable to position the saddle section B2 below the straight path 28 in order to align the sheets using gravity as well.

[0031] <Saddle buffer path> A saddle buffer path P2 is connected to the straight path 28 for temporarily loading and holding sheets that will undergo saddle stitching and folding at the saddle section B2. A saddle buffer path flapper 33a is configured to guide the sheets into this saddle buffer path P2. The saddle buffer path P2 is also equipped with transport rollers 302 (302a, 302b) for loading and temporarily holding sheets.

[0032] A fourth tray output port 305 is provided on the downstream extension of the saddle buffer path P2, making it possible to discharge and load sheets that have been brought into the saddle buffer path P2 onto the fourth tray 310. In this case, the fourth tray 310 is positioned vertically above the saddle buffer path P2. The fourth tray 310 may be shared with the exterior components on the top surface of the sheet post-processing device B, it may be fixed to the device housing, or it may be configured to be able to move up and down in a substantially vertical direction with a drive mechanism.

[0033] Furthermore, the device can be made more compact by positioning the saddle buffer path P2 so that it overlaps the punch unit 100 vertically above it. However, if space is needed to lift the punch unit 100 upwards to remove any sheets that have accumulated in it, the saddle buffer path P2 may be positioned so that it does not overlap the punch unit 100 vertically above it.

[0034] <Conveyor roller shift mechanism in the delivery route> Here, the transport shift mechanism provided by the transport rollers on the transport path described above will be explained using Figures 6 and 7. The first transport roller 201, the second transport roller 202, the third transport roller 203, and the transport rollers 302a and 302b are composed of 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. The drive roller shaft 113 is connected to a drive rotating shaft by a transmission mechanism 116 (a gear transmission in the figure), and the drive rotating shaft 115 is connected to a drive motor (not shown) that is common to the paper discharge roller 36. The driven roller shaft 114 is also rotatably supported by bearings on the left and right side frame frames 70f and 70r.

[0035] Each of the above-mentioned conveying rollers is rotatably mounted on 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 integrally 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 frame frames 70f and 70r, with one end of the drive roller shaft 113 located in the area indicated by the axial movement region of the conveying roller on the front side of the side frame frame 70f, and the other end 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, integrally connecting both roller shafts.

[0036] A rack 117a is integrally formed with the shift member 117, and it meshes with a shift motor M9 and a transmission pinion 117b mounted on the side frame 70r (device frame; the same applies hereafter). With this configuration, the shift member 117 can be moved (shifted) in the axial direction of the transport roller by the rotation of the shift motor M9 (shown in the figure as a stepping motor capable of forward and reverse rotation).

[0037] A driven gear 118 is integrally formed with the drive rotating shaft 115, and the rotation of the drive motor is transmitted to the driven gear 118. In addition, a pair of conveying rollers (a drive roller and a driven roller) are pressed against the driven rotating shaft 119 so that it rotates in response to the rotation of the drive rotating shaft 115.

[0038] In this embodiment, the drive shaft 115 and the driven shaft 119 are connected to each other and configured to move in the axial direction of one, causing the other to move in the axial direction. Alternatively, one of the drive roller 111 and the driven roller 112 may be mounted on the rotating shaft so as to be slidable in the axial direction, and the other roller may be moved in the axial direction and configured to move in conjunction with that movement.

[0039] <Conveyor shift operation> Here, we will explain the shift operation (jog sorting mode) of the sheet that has been brought into the sheet post-processing device B. The sheet fed from the image forming apparatus A is transported in the following order: straight path entrance 26, entrance roller 29, first transport roller 201, second transport roller 202, and third transport roller 203. At this time, the entrance sensor Se1 also detects the timing of the sheet handover. As the sheet is brought in by the entrance roller 29, the position of the edge of the sheet is detected by the lateral registration detection sensor S0 as it passes through the straight path 28. The lateral registration detection sensor S0 detects how much of a lateral registration error X has occurred in the sheet relative to the center position.

[0040] When the horizontal register error X is detected by the horizontal register detection sensor S0, the first transport roller 201, the second transport roller 202, and the third transport roller 203 move a predetermined amount in the forward and backward directions while transporting the sheet, causing a sheet shift operation (also called "horizontal register detection processing"). After that, the sheet is distributed by the upper transport path flapper 34 of the branching mechanism to either the straight path paper output port 35 or the upper transport path 30, and transported, and discharged onto the first tray 49 or the second tray 71.

[0041] <Processing> The processing unit B1 is a post-processing unit located downstream of the straight path 28 and includes a processing tray 37 that aligns and accumulates sheets sent from the straight path paper output port 35, and a binding mechanism that binds the accumulated sheet bundles. As shown in Figure 3, the processing tray 37 is positioned below the straight path paper output port 35 of the straight path 28, forming a step, and a first paper output path (first switchback path) 31 is formed between the straight path paper output port 35 and the processing tray 37, which reverses the transport direction from the paper output port and guides the sheets onto the tray.

[0042] Between the straight-path paper output port 35 and the processing tray 37, a sheet loading mechanism is provided to load sheets from the paper output port onto the tray. The processing tray 37 is equipped with a positioning mechanism to position sheets at predetermined binding positions and a sheet bundle discharge mechanism to discharge the bound sheet bundles to the downstream first tray 49. Each of these components will be described later.

[0043] Furthermore, the processing tray 37 shown in Figure 3 bridges and supports the sheets fed from the straight-path paper output port 35 between itself and the downstream first tray 49. In other words, the sheet fed from the straight-path paper output port 35 is supported by bridging its leading edge onto the top sheet of the downstream first tray 49 and its rear end onto the processing tray 37.

[0044] <Saddle section> Saddle section B2 is a post-processing unit that aligns and stacks the sheets fed from the straight path 28, binds the center section, and performs inward folding (hereinafter referred to as "magazine finishing"). A second tray 61 is positioned downstream of saddle section B2 to store the bound sheet bundles. Alternatively, the system may be configured to align and stack one or more sheets and perform only inward folding of the center section without saddle stitching.

[0045] The saddle section B2 is composed of a guide member 66 for stacking sheets in a bundle, a front-end regulating stopper 67 for positioning the sheets at a predetermined position on the guide member 66, a stapling device 63 (saddle-stapling stapling unit) for stapling the central part of the sheets positioned by the front-end regulating stopper 67, and a folding mechanism (folding roll pair 64 and folding blade 65) for folding the sheet bundle in the center after the stapling process.

[0046] The saddle-stitch stapling unit 63 employs a commonly known mechanism in which the sheet bundle is sandwiched between a head unit and an anvil unit and then moved along the center (line) of the sheet to perform the stapling process. Furthermore, as shown in Figure 2, the folding mechanism is configured such that the fold of the sheet bundle is inserted into a pair of folding rolls 64 that are pressed against each other by a folding blade 65, and the sheets are folded by the rolling motion of the pair of rolls.

[0047] The illustrated processing unit B1 and straight path 28 are arranged in a substantially horizontal direction, the saddle path 32 that guides the sheet to the saddle section B2 is arranged in a vertical direction, and the guide member 66 that aligns and stacks the sheets is also arranged in a substantially vertical direction. 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, the device can be made slimmer. In this embodiment, the saddle section B2 refers to the tray that supports the sheet, the binding unit, and the folding unit. By arranging it so that the lower end is located downstream in the transport direction (left side in Figure 2) than the upper end when the largest size sheet is supported by the guide member 66, miniaturization in the transport direction is achieved.

[0048] A second tray 61 is positioned downstream of the saddle section B2, and is capable of storing a magazine-like bundle of sheets. The second tray 61 is positioned 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 the sheets from the tray.

[0049] <Punch Unit> A punch unit 100, which is positioned on the straight path 28 and punches holes in the sheet fed from the straight path entrance 26, will be explained with reference to Figure 5. The punch unit 100 arranges a plurality of punch members 101a to 101e at predetermined intervals in a direction perpendicular to the sheet transport direction of the straight path 28, and punches a selected number of holes in the sheet.

[0050] Figure 4 shows the overall configuration of the punch unit 100. The punch unit 100 consists of 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 (reciprocates in the punching direction), and a drive motor M7 that drives the drive cam.

[0051] Figure 104 is a waste box, located below the punch member 101, for storing punched waste paper. The waste box 104 is slidably mounted on a guide rail (not shown) on the device frame 70 (different from the unit frame). Figure 106 is a rotary operating member, which forcibly rotates the drive cam when a jam occurs in the punch member 101 or when a malfunction occurs in the drive motor M7, thereby pulling away (peeling off) the punch member 101 that is stuck in the sheet. For this reason, the rotary operating member 106 consists of a manual rotary knob connected to the rotation shaft 107 of the drive cam.

[0052] As shown in Figure 5, the unit frame 102 is composed of 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. Multiple punch members 101a to 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 "conveying orthogonal direction") so as to be able to reciprocate (move up and down) in the punching direction. Punching holes (dies) are formed on the lower frame 102b at positions opposite to each punch part 101. A drive rotating shaft 107 is also arranged on the unit frame 102, and a drive cam that moves each punch member 101 up and down is attached to the drive rotating shaft 107. A drive motor M7 is connected to the drive rotating shaft 107 via a transmission mechanism.

[0053] The drive cam is axially mounted on the drive rotation shaft 107 and consists of cylindrical cam members corresponding to multiple punch members 101, with each punch member 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 by a predetermined angle. At this time, the first group of multiple punch members 101b, 101d (for example, 2-hole punching) moves up and down in the punching direction at a first rotation angle of the drive rotation shaft 107, while the second group 101a, 101c, 101e (for example, 3-hole punching) moves up and down in the punching direction at a different second rotation angle.

[0054] Therefore, the binding processing control unit 95, described later, can cause the first group of punch members 101b and 101d to punch when the drive rotation shaft 107 is rotated back and forth within a preset angular range by controlling the motor M7, and can cause the second group of punch members 101a, 101c, and 101e to punch when it is rotated back and forth within a different angular range.

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

[0056] Furthermore, the drive motor M7 is connected to the drive rotating shaft 107 via a reduction mechanism (gear transmission mechanism), and the rotating member is positioned on the front side of the side frame 70f, passing through a hole in the side frame 70f, so that the operator can rotate it manually. On the front side of the device, a front cover is positioned so that it can be opened and closed, and the rotating operating member 106 can be operated when the cover is open. Note that when the cover is open, the drive motor M7 is not supplied with power (shut off).

[0057] [Configuration of the processing area] Next, we will describe the configurations of the sheet loading mechanism, sheet positioning mechanism, binding mechanism, and sheet bundle discharge mechanism of the processing unit B1.

[0058] <Sheet loading mechanism> As shown in Figure 3, between the straight-path paper output port 35 and the processing tray 37, there is a reversal transport mechanism that switches back and transports the sheet from the straight-path paper output port 35 in the paper output direction and the opposite direction of paper output, a guide mechanism (sheet guide member) 44 that guides the sheet towards the tray, and a scraping rotating body 46 that guides the sheet to the rear end restricting section.

[0059] The reversing transport mechanism includes a lifting roller 41 that moves up and down between an operating position that engages with the sheet being transported onto the processing tray 37 and a standby position that is separated from it, and a paddle rotating body 42 that transports the sheet in the opposite direction to the paper discharge. The lifting roller 41 and the paddle rotating body 42 are attached to a swing bracket 43.

[0060] A swing bracket 43 is positioned on the device frame 27 so as to be able to swing around a rotation axis (e.g., the paper discharge roller axis), and the rotation axes of the lifting roller 41 and the paddle rotor 42 are supported by bearings on the swing bracket 43. A lifting motor (not shown) is connected to the swing bracket 43, and the swing bracket 43 moves the mounted lifting roller 41 and paddle rotor 42 up and down between an operating position in which they engage with the sheet and a standby position separated from the sheet.

[0061] Furthermore, a drive motor (not shown) is connected to the lifting roller 41 and the paddle rotor 42, and the drive is transmitted so that the lifting roller 41 rotates in the forward and reverse directions, and the paddle rotor 42 rotates in the reverse direction (opposite direction of paper discharge). In addition, a driven roller 48 is arranged in the processing tray 37, which presses against the lifting roller 41, and nips a single sheet or a bundle of sheets and discharges it downstream.

[0062] Between the lifting roller 41 and the scraping rotating body 46 (described later), a guide mechanism is positioned to guide the rear end of the sheet fed onto the processing tray 37 toward the sheet end restricting section 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 Figure 3. The sheet guide member 44 retracts to the dotted line position when a sheet is discharged from the straight-path paper discharge port 35, and guides the rear end of the sheet onto the processing tray 37 after the rear end of the sheet has passed through the straight-path paper discharge port 35. For this purpose, a drive mechanism (not shown) is connected to the sheet guide member 44, and it moves up and down in accordance with the timing of guiding the rear end of the sheet from the straight-path paper discharge port 35 onto the processing tray 37.

[0063] <Seat positioning mechanism> The processing tray 37 is equipped with positioning mechanisms 38 and 39 for positioning sheets at predetermined binding positions. The illustrated mechanism includes a sheet edge restricting section 38 that abuts and restricts 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-sided side reference).

[0064] The sheet edge regulating section 38 is composed of a stopper member that abuts and restricts the rear end of the sheet, as shown in Figure 3. The side edge alignment member 39 will be described later in Figure 9, but the sheet is ejected from the straight path 28 with the center as the reference point, and depending on the type of binding mode, positioning is performed either with the same center reference point or with one side as the reference point.

[0065] <Side edge alignment mechanism> As shown in Figure 9, the side edge alignment plates 39F and 39R protrude upward from the paper loading surface 37a of the processing tray 37 and have regulating surfaces 39x that engage with the side edges of the sheets, and are arranged in pairs facing each other. These pair of side edge alignment sections 39 are positioned on the processing tray 37 so as to be able to reciprocate within a predetermined stroke. This stroke is set by the size difference between the largest and smallest size sheets and the offset amount used to move (offset transport) the aligned sheet bundle in either the left or right direction.

[0066] In other words, the movement stroke of the left and right side edge alignment plates 39F and 39R is set by the amount of movement required to align sheets of different sizes and the offset amount of the sheet bundle after alignment. When corner binding is performed, the side edge alignment plates 39F and 39R move a predetermined amount to the right when right corner binding is performed and to the left when left corner binding is performed, relative to the center of the sheet that was discharged (offset movement). This offset movement can be performed one sheet at a time each time a sheet is loaded into the processing tray 37 (for each loaded sheet), or it can be performed by moving the bundle as a whole in order to perform the binding process after the sheets have been aligned into a bundle.

[0067] Therefore, as shown in Figure 9, the side edge alignment portion 39 is composed of a right-side edge alignment member 39F (front side of the device) and a left-side edge alignment member 39R (rear side of the device), and both side edge alignment members are supported on the processing tray 37 such that regulating surfaces 39x that engage with the side edge of the sheet move toward or toward each other. The processing tray 37 is provided with a slit groove (not shown) that penetrates both sides, and the side edge alignment portion 39 having a regulating surface 39x that engages with the side edge of the sheet is slidably fitted into this slit groove.

[0068] Each side edge alignment plate 39F, 39R is slidably supported on the back side of the tray by a plurality of guide rollers 80 (which may also be rail members), and a rack 81 is integrally formed. Alignment motors M1, M2 are connected to the left and right racks 81 via pinions 82. The left and right alignment motors M1, M2 are 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 of movement based on the detected value. Note that the rack-pinion mechanism is not limited to the one shown, and each side edge alignment plate 39F, 39R may be fixed to a timing belt and connected by pulleys to a motor that reciprocates the timing belt left and right.

[0069] With the configuration described above, the binding processing control unit 95, described later, places the left and right side edge alignment members 39F and 39R in a predetermined standby position (sheet width + α position) based on the sheet size information provided by the image forming apparatus A. When performing "multi-binding", sheets are loaded onto the processing tray 37, and the alignment operation starts when the sheet edge abuts against the sheet edge restricting 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). As a result, the sheets loaded onto the processing tray 37 are positioned relative to the sheet center and stacked in bundles. By repeating this sheet loading operation and alignment operation, the sheets are bundled and accumulated on the processing tray 37. At this time, sheets of different sizes are positioned relative to the center. When performing "corner binding", sheets are loaded onto the processing tray 37, and the alignment operation starts when the sheet edge abuts against the sheet edge restricting unit 38. This alignment operation is performed by making the amount of movement of the alignment plate on the binding position side and the alignment plate on the opposite side of the binding position different. The amount of movement is then set so that the sheet corner is positioned at a predetermined binding position.

[0070] <Binding mechanism> The processing tray 37 is equipped with a binding mechanism 47 for binding stacks of sheets accumulated on the paper loading surface 37a. The paper loading surface 37a on the processing tray 37 is positioned at a predetermined binding position by a positioning mechanism (sheet edge regulating part 38 and side edge alignment part 39). The binding mechanism 47 is configured as a binding unit 47 (hereinafter referred to as "staple unit") that staples the stacks of sheets together.

[0071] The processing tray 37 is equipped with a stapling mechanism 47 that staples the rear end of the sheet fed in from the straight-path paper output port 35. As shown in Figure 8, the stapling mechanism 47 consists of a staple unit 47 that can move along the rear end of the paper loading surface 37a of the processing tray 37.

[0072] Figures 8 and 9 show a staple unit 47 positioned on a processing tray 37. In Figure 9, the stapling position Cp1 is set at the sheet corner located on the left side of the drawing. The staple unit 47 moves along a first travel rail 53 and a second travel rail 54 formed on the device frame 27b with a predetermined stroke SL1.

[0073] Figure 9 shows the sheets loaded into the processing tray 37 and the movement stroke SL1 of the binding unit 47. Sheets of different sizes are loaded into the processing tray 37, from the largest to the smallest size, based on the center. A pair of left and right side edge alignment plates 39F and 39R align these sheets so that sheets of different sizes match, based on the binding side edge of the sheet (the left edge in the illustration). For this purpose, the left and right side edge alignment plates 39F and 39R are connected to different drive motors M1 and M2, respectively, and the binding processing control unit 95, described later, sets the amount of movement of the left and right side edge alignment plates 39F and 39R according to the sheet size.

[0074] Furthermore, the binding control unit 95, described later, aligns the sheet based on the center when performing binding processes other than binding the sheet corners, such as the multi-binding mode described later. In this case, the left and right side edge alignment plates 39F and 39R are moved by the same amount from their standby positions toward the center of the sheet to position the sheet at the binding location.

[0075] As illustrated in Figure 9, the binding unit 47 moves a stroke SL1 between the standby position Wp1 (first standby position) and the binding position Cp1. In other words, the binding unit 47 reciprocates between the standby position Wp1 and the binding position Cp1 along the travel rails 53, 54 (guide grooves, guide rods, etc.). The first standby position Wp1 is set outside the largest size sheet to be bound on the processing tray 37.

[0076] Figure 10 shows the configuration of the stapling unit 47. On the device frame 27b, a pair of pulleys 58a and 58b are arranged along the movement area of ​​the staple unit 47 (left-right direction in Figure 9), and a timing belt 59 (toothed belt) is stretched between the two pulleys, with a drive motor M3 (stepping motor) connected to one of the pulleys 58a.

[0077] <Mechanism for moving staples> As shown in Figure 8, the staple unit 47 is mounted on the device 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 device frame 70, so as to be movable within a predetermined stroke. The device frame 27b has a first running rail 53 and a second running rail 54. The first running rail 53 has a running rail surface 53x, and the second running rail 54 has a running cam surface 54x. The running rail surface 53x and the running cam surface 54x cooperate with each other to support the staple unit 47 (hereinafter referred to as the "movable unit" in this section) so that it can reciprocate within a predetermined stroke, and at the same time control its angular orientation.

[0078] The first running rail 53 and the second running rail 54 have rail surfaces 53x and running cam surfaces 54x formed so that they reciprocate within the range of motion of the moving unit. As shown in Figure 10, a timing belt 59 connected to a drive motor (running motor) M3 is fixed to the staple unit 47. The timing belt 59 is wound around a pair of pulleys 58a and 58b pivotally supported on the device frame 27b, and the drive motor M3 is connected to one of the pulleys. Therefore, the staple unit 47 reciprocates with a stroke SL1 by forward and reverse rotation of the drive motor M3.

[0079] The staple unit 47 engages with the first and second running rails 53 and 54 as follows. As shown in Figure 8, the staple unit 47 is provided with a first rolling roller 83 (rail fitting member) that engages with the running rail surface 53x and a second rolling roller 84 (cam follower member) that engages with the running cam surface 54x. The staple unit 47 also has ball-shaped sliding rollers 47x (two in the figure) that engage with the support surface of the frame 27b. In addition, the staple unit 47 has guide rollers 47y that engage with the bottom surface of the bottom frame, preventing the staple unit 47 from floating away from the device frame 27b.

[0080] With the above configuration, the staple unit 47 is supported on the device frame 27b so as to be movable by sliding rollers 47x and guide rollers 47y. The first rolling roller 83 rotates along the running rail surface 53x, and the second rolling roller 84 rotates along the running cam surface 54x, moving in accordance with the rail surface 53x and the cam surface 54x.

[0081] <Stackable tray lifting mechanism> As shown in Figure 11, the sheet post-processing device B is equipped with a first tray 49. The first tray 49 is configured to move up and down according to the amount of sheets loaded. For this purpose, guide rollers 85 are provided at two locations, upper and lower, at the base end of the first tray 49, and the guide rollers 85 are fitted and supported by a lifting guide 86 provided on the device frame 27. A lifting gear 88 is provided at the base end of the first tray 49 and is connected to a lifting rack gear 87. A lifting motor M4 is also 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 amount of sheets loaded.

[0082] <Sheet bundle unloading mechanism> The processing tray 37 is equipped with a sheet bundle discharge mechanism that discharges the bound sheet bundles toward the first tray 49 downstream. Known configurations for transporting sheet bundles downstream include a method using a pair of rollers that press against each other (discharge roller mechanism) and a conveyor mechanism that pushes out the rear end of the sheets with an extrusion member that moves along the tray surface from upstream to downstream. The illustrated device employs both of these methods.

[0083] Figures 12(a) to 12(c) show the sheet bundle discharge mechanism. The conveyor mechanism includes an extrusion projection 45 that transfers the sheets from the binding position (processing position) located upstream along the processing tray 37 to the stack tray (first tray) 49 downstream, a conveyor belt 45v that moves the extrusion projection, and a drive motor M6. A driven roller 48 is positioned at the discharge port (boundary between the paper loading surface 37a and the first tray 49) of the processing tray 37, and a lifting roller 41 that presses against the driven roller 48 is positioned opposite it, so that the driven roller 48 and the lifting roller 41 constitute the discharge roller mechanism.

[0084] Therefore, the processing tray 37 is equipped with conveyor mechanisms 45 and 45v that push the sheet bundle from the upstream side to the downstream side, and discharge roller mechanisms 48 and 41 that nip the sheet bundle and discharge it. Figure 12(a) shows the state in which the sheet bundle is located at the binding position on the processing tray 37. At this time, the conveyor mechanisms 45 and 45v and the discharge roller mechanisms 48 and 41 are in operation. Figure 12(b) shows the state in the process of transporting the sheet bundle from the processing position to the downstream side, where the sheet bundle is sent downstream by the movement of the extrusion projection 45 and the rotation of the discharge roller mechanisms 48 and 41. Figure 12(c) shows the state just before the sheet bundle is discharged to the first tray 49 on the downstream side, where the sheet bundle is gradually (at a low speed) sent downstream on the processing tray by the rotation of the discharge roller mechanisms 48 and 41. At this time, the extrusion projection 45 is waiting at the shown position and returns to its initial position (moves backward).

[0085] <Configuration of the staple unit> The configuration of the staple unit described above will be explained with reference to Figure 13. The staple unit 47 is configured as a separate unit from the sheet post-processing device B. A box-shaped unit frame 47a, a drive cam 47d pivotably supported on the unit frame 47a, and a drive motor M4 that rotates the drive cam 47d are mounted on the unit frame 47a.

[0086] The drive cam 47d has a staple head 47b and an anvil member 47c positioned opposite each other at the stapling position. The staple head 47b is biased by a biasing spring (not shown) on the drive cam 47d to move up and down from an upper standby position to a lower stapling position (anvil member). The needle cartridge 52 is detachably mounted on the unit frame 47a.

[0087] The needle cartridge 52 houses a straight blank needle, and the needle feeding mechanism supplies the needle to the staple head 47b. The staple head 47b contains a former member that bends the straight needle into a U-shape and a driver that presses the bent needle into the sheet bundle. With this configuration, the drive motor M4 rotates the drive cam 47d, storing energy in the biasing spring. When the rotation angle reaches a predetermined angle, the staple head 47b rapidly descends towards the anvil member 47c. In this action, the staple needle is bent into a U-shape and then inserted into the sheet bundle by the driver. The tip of the needle is then bent by the anvil member 47c and stapled.

[0088] Furthermore, a needle feeding mechanism is built between the needle cartridge 52 and the staple head 47b, and the needle feeding mechanism is equipped with a sensor (empty sensor) for detecting the absence of a needle. In addition, a cartridge sensor (not shown) is equipped on the unit frame 47a for detecting whether or not the needle cartridge 52 is inserted.

[0089] The staple cartridge 52 employs a structure in which staples connected in a strip are stacked and stored in a box-shaped cartridge, and a structure in which they are stored in a roll. The unit frame 47a is provided with circuits for controlling each of the above-mentioned sensors and a circuit board for controlling the drive motor M4, and is configured to emit a warning signal when the staple cartridge 52 is not stored or when the staples are empty. The staple control circuit controls the drive motor M4 to perform stapling operations in response to the staple signal, and is configured to emit an "operation completion signal" when the staple head unit 47b moves from the standby position to the stapling position and then returns to the standby position.

[0090] <Description of control configuration> The control configuration of the image forming system shown in Figure 1 will be explained with reference to Figure 14. The image forming system shown in Figure 14 comprises a control unit 90 of the image forming apparatus A (hereinafter referred to as the "main unit control unit") and a control unit 95 of the sheet post-processing device B (hereinafter referred to as the "binding processing control unit"). The main unit control unit 90 controls the print control unit 91, the paper feed control unit 92, and the input unit 93 (control panel).

[0091] Then, based on user operations received via the input unit 93 (control panel), the "image formation mode" and "post-processing mode" are set. In the image formation mode, for example, mode settings such as color / monochrome printing and double-sided / single-sided printing are set, as well as image formation conditions such as sheet size, sheet paper quality, number of printouts, and enlargement / reduction printing are set. In the "post-processing mode," for example, "printout mode," "binding process output mode," "staple binding process mode," and "jog sorting mode" are set.

[0092] Furthermore, the main unit control unit 90 transmits data to the binding processing control unit 95 indicating that it is in post-processing mode, the number of sheets, the number of copies, and the paper thickness information of the sheets to be image-formed. Simultaneously, the main unit control unit 90 transmits a job completion signal to the binding processing control unit 95 each time image formation is completed.

[0093] To explain the post-processing modes described above, the "printout mode" is a mode in which sheets from the straight-path paper output tray 35 are placed in the stack tray 49 via the processing tray 37 without binding. In this case, the sheets are stacked on top of each other in the processing tray 37, and the stacked sheet bundle is discharged to the stack tray 49 upon receiving a job completion signal from the main unit control unit 90.

[0094] The "product processing output mode" is a mode in which image-formed sheets are aligned, bound, folded, and then finished into a book. Details will be described later in Figure 15.

[0095] The "staple binding processing mode" is a mode in which sheets from the straight path output tray 35 are collected and aligned on the processing tray 37, and after this sheet bundle is bound, it is placed in the stack tray 49. In this case, the operator specifies that the sheets on which the image is formed should, in principle, be of the same paper thickness and size. In this staple binding processing mode, one of the following is selected and specified: "multi-stapling," "right corner binding," or "left corner binding."

[0096] In "jog sorting mode," the sheets formed by the image forming apparatus A are divided into two groups: one group that is offset and stacked, and another group that is stacked without offset movement. The stack tray is then stacked with alternating bundles of offset-moved and non-offset-moved sheets.

[0097] <Binding Processing Control Unit> The binding control unit 95 operates the sheet post-processing device B according to the post-processing mode set by the image forming control unit 90. The binding control unit 95 includes a control CPU. A ROM 96 and a RAM 97 are connected to the binding 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 control unit 95 controls the drive circuits of all the aforementioned drive motors and controls the starting, stopping, and forward / reverse rotation of each motor.

[0098] The binding and paper output mode, one of the post-processing modes, will be explained in accordance with Figure 15. S101 to S102 show the processing in the image forming apparatus A, and S103 to S113 show the processing in the sheet post-processing apparatus B. Specifically, the processing in S101 to S102 is achieved, for example, by the main unit control unit 90 reading a program stored in ROM into RAM and executing it. The processing in S103 to S115 is achieved, for example, by the binding processing control unit 95 reading a program stored in ROM 96 into RAM 97 and executing it.

[0099] In S101, the main unit control 90 forms an image on the sheet, and in S102, the sheet with the image formed on it is ejected. The sheet with the image formed on it by the image forming apparatus A is guided to the straight path 28.

[0100] In S103, the binding processing control unit 95 controls each motor to transport the sheet ejected from the image forming apparatus A along the path to the leading edge regulating stopper 67. The sheet transport control in S103 will be described later.

[0101] In S104, the binding control unit 95 moves the position of the leading edge regulating stopper 67 to a position where a sheet can be fed in. At this time, the binding control unit 95 sets the position of the leading edge regulating stopper 67 based on the size of the sheet in the transport direction, which is received from the image forming apparatus A. In S105, the binding control unit 95 feeds the sheet into the moved leading edge regulating stopper 67. The fed sheet comes into contact with the receiving part of the leading edge regulating stopper 67, so that the leading edges of the sheets are aligned.

[0102] In S106, the binding processing control unit 95 determines whether the final sheet has been loaded into the leading edge regulating stopper 67 based on a specified number of sheets for post-processing. The process from S105 is repeated until it is determined that the final sheet has been loaded into the leading edge regulating stopper 67. If it is determined that the final sheet has been loaded into the leading edge regulating stopper 67, the process proceeds to S107.

[0103] In S107, the binding control unit 95 moves the position of the front-end regulating stopper 67, into which the specified number of sheets have been loaded, to the lowest position. In S108, the binding control unit 95 aligns the sheets in the width direction. This sheet alignment is performed by a side-edge regulating member (not shown).

[0104] In S109, the binding control unit 95 rotates the folding roll 64. In S110, the binding control unit 95 moves the folding blade 65 in the folding direction. In S111, the binding control unit 95 determines whether the amount of rotation of the folding roller 64 has reached a predetermined amount. If it is determined that the amount of rotation of the folding roller 64 has not reached a predetermined amount, the process in S111 is repeated. If it is determined that the amount of rotation of the folding roller 64 has reached a predetermined amount, the process proceeds to S112. In S112, the binding control unit 95 retracts the folding blade 65. In S113, the binding control unit 95 transports the folded sheet, which has undergone the above folding process, in the paper discharge direction by the paper discharge roller on the downstream side of the saddle section. As a result, the folded sheet is stored in the second tray 61 via the saddle discharge path 68.

[0105] The above describes an example in which the folding process is performed after the position of the front-end regulating stopper 67 moves in S107, but the configuration is not limited to this. Other post-processing may be performed after the position of the front-end regulating stopper 67 has moved and before the folding process is performed. For example, a binding process may be performed. For example, based on the receipt of a job completion signal from the image forming apparatus A, a binding unit (saddle stitching unit) not shown, provided in the saddle section B2, may be moved to the center of the sheet to perform the binding process. In this case, the binding process is performed at one or two specified positions.

[0106] While post-processing is being performed in the saddle section B2, image formation continues in the image forming apparatus A. Therefore, in this embodiment, a buffer operation is performed in which the sheets transported from the image forming apparatus A are stored in the sheet processing apparatus B. This allows post-processing to continue without reducing the frequency of sheets being discharged from the image forming apparatus A, that is, without reducing the productivity of the image forming apparatus A.

[0107] Referring to Figures 16(a) to 23, an overview of the sheet buffer operation within the sheet processing device B executed in S103 will be explained. Figures 16(a) to 23 show cross-sectional views of the sheet processing device B as seen from the side. Hereinafter, the first transport roller 201, the second transport roller 202, and the third transport roller 203 will be referred to as the shift roller 201, the shift roller 202, and the intermediate transport roller 203.

[0108] First, we will explain the buffer operation for small-sized sheets in the sheet transport direction. In this embodiment, as an example of the definition of small size, a size that fits within the path length of the straight path 28 is defined as small size.

[0109] Figure 16(a) shows the processing steps S109 to S112 in Figure 15 being performed on the sheet S0 already present in the sheet processing device B at the saddle section B2. Also, Figure 16(a) shows the state in which the sheet S1 discharged from the image forming apparatus A has been transported through the straight path inlet 26 to the inlet roller 29 and shift roller 201, at which point the inlet sensor Se1 detects the leading edge. In the state shown in Figure 16(a), the lateral registration error for the sheet S1, which will be described later, is detected. Figure 16(b) shows the state in which the leading edge of the sheet S1 has been transported to a position beyond the shift roller 202. At this point, the lateral registration adjustment for the sheet S1, which will be described later, is performed.

[0110] Figure 17(a) shows the state where the leading edge of the sheet S1 has been transported to a position beyond the paper output roller 36. Figure 17(b) shows the state where the upper flapper 33a has been moved to the buffer path guide position. This buffer path guide position is set to a position where the sheet can be fed into the saddle buffer path P2 based on the leading edge detection result from the inlet sensor Se1 and the paper length information. If the sheet reaches the paper output sensor Se2, the detection result of Se2 may be used instead or in combination.

[0111] Figure 18(a) shows the lower flapper 33b in a position moved to the buffer path guide position. The movement of the upper flapper 33a and the lower flapper 33b creates a path for transporting the sheet S1 to the saddle buffer path P2. Figure 18(b) shows the sheet S1 being moved to the saddle buffer path P2. In this embodiment, by moving the sheet S1 to the saddle buffer path P2, sheets subsequently discharged from the image forming apparatus A can be continuously received into the straight path 28. Figure 18(b) also shows that post-processing (folding) of the sheet S0 is in progress. Here, "in progress" refers not only to the folding process but also to the state where the folding process itself is completed but the sheet has not yet been discharged into the second tray 61.

[0112] Figure 19(a) shows the state in which sheet S1 is further transported toward the fourth tray output port 305 of the saddle buffer path P2. At this time, post-processing of sheet S0 is being performed. Figure 19(b) shows the state in which the position of the lower flapper 33b has been moved. By moving the lower flapper 33b, the subsequent sheet S2 can be received into the straight path 28.

[0113] Figure 20(a) shows the state where sheet S1 is positioned in a predetermined location on the saddle buffer path P2. As shown in Figure 20(a), the entire length of the sheet in the transport direction is retracted into the saddle buffer path P2. The retraction position of the saddle buffer path P2 is set based on the leading edge detection result by the entrance sensor Se1 and the paper length information. At this time, post-processing for sheet S0 is being performed. Figure 20(b) shows the state where sheet S2, which has been discharged from the image forming apparatus A, has been transported through the straight path entrance 26 to the entrance roller 29 and shift roller 201. At this time, the leading edge of sheet S2 is detected by the entrance sensor Se1. In the state shown in Figure 20(b), the lateral registration error for sheet S2, which will be described later, is detected. At this time, sheet S1, which is located on the saddle buffer path P2, undergoes lateral registration adjustment to match the lateral registration error of sheet S2. This operation will be described later. Also, at this time, post-processing for sheet S0 is being performed.

[0114] Figure 21(a) shows the state where sheets S1 and S2 have been transported synchronously to the shift roller 202. The transport synchronization between sheets is performed, for example, based on the detection result of the entrance sensor Se1, paper length information, and paper position information from the drive pulses of the stepping motor. Based on the detection result of the leading edge of sheet S2 by the entrance sensor Se1, the buffer roller 302 is driven to feed sheet S1 into the straight path 28 in alignment with the leading edge of sheet S2. At this time, post-processing for sheet S0 is being performed. Figure 21(b) shows the state where sheets S1 and S2 have been transported synchronously to just before the intermediate transport roller 203. At this time, lateral register adjustment is performed to align sheets S1 and S2 to the center. This operation will be described later. Also at this time, post-processing for sheet S0 is being performed.

[0115] Figure 22(a) shows the state in which sheets S1 and S2 are stacked on top of each other and transported to the paper discharge roller 36. At this time, the rear ends of sheets S1 and S2 have passed the shift roller 201. Also, post-processing for sheet S0 is being performed at this time. Figure 22(b) shows the state in which the positions of the upper flapper 33a and the lower flapper 33b have been moved. The movement of the upper flapper 33a and the lower flapper 33b creates a path for transporting sheets S1 and S2 to the saddle section B2. At this time, sheet S0 has been discharged to the second tray 61. Figure 23 shows the state in which sheets S1 and S2 have been loaded into the front-end regulating stopper 67.

[0116] Thus, according to this embodiment, even when post-processing is being performed on a sheet in the saddle section B2, sheet S1 can be moved to the saddle buffer path P2, and the subsequent sheet S2 can be received from the image forming apparatus A. This allows post-processing to be performed on the sheet without impairing the productivity of the image forming apparatus A. Furthermore, as a result of the tip being brought into contact with the tip restricting stopper 67, sheets S1 and S2 are stacked in order from the bottom of the stacked state, thus maintaining the order between multiple sheets. Moreover, since the buffered sheets S1 and S2 are sent to the saddle section B2 in an aligned state, the bundle of buffered sheets can be quickly moved out of the straight path 28, thus speeding up the timing of receiving the next sheet. In this embodiment, a state in which buffered sheets S1 and S2 are relatively aligned means that the amount of misalignment in the transport direction is within a predetermined range, for example, within a range of 0 mm to +10 mm or within a range of 0 mm to -10 mm. In this embodiment, the standard value is adjusted so that the preceding sheet S1, which has entered the saddle buffer path P2, is positioned about 2.5 mm behind the following sheet S2. This allows the sheet S1 on the right to come into contact with the front-end regulating stopper 67 first when the sheet bundle of sheets S1 and S2 is fed into the saddle section B2, making it easier for the sheets to align. Furthermore, by controlling the rear end of sheet S1 to be behind sheet S2 within a predetermined range, even taking various tolerances into account, it is possible to ensure a timing for quick retraction from the straight path 28, allowing the next sheet to be accepted sooner and increasing productivity.

[0117] Furthermore, by positioning the entrance to the saddle path 32 and the position where the sheet overlapping is completed (the exit of the saddle buffer path P2) close together in the transport direction, the transport distance required to move the sheet away from the straight path 28 is shortened, improving productivity. In addition, the saddle buffer path flapper 33a and saddle path flapper 33b, which feed the sheets from the straight path 28 to each path, can be used interchangeably. Moreover, by performing the operation of feeding to the saddle buffer path P2 two or more times, it is possible to process three or more sheets as buffers.

[0118] In parts of Figures 16(a) to 23, it was stated that lateral register error detection and lateral register adjustment are performed. Below, the detection and adjustment of lateral register error will be explained with reference to Figures 24(a) to 33(b). The upper part of Figures 24(a) to 33(b) is a simplified diagram showing the configuration near the straight path 28 in Figures 16(a) to 23. The lower part of Figures 24(a) to 33(b) is a view of the upper straight path 28 from the top of the device. In addition, the inlet roller 29, shift roller 201, shift roller 202, intermediate conveyor roller 203, buffer rollers 302a and 302b in the lower part of Figures 24(a) to 33(b) correspond to the inlet roller 29, shift roller 201, shift roller 202, intermediate conveyor roller 203, buffer rollers 302a and 302b in the upper part of Figures 24(a) to 33(b). Furthermore, as shown above, the rollers placed on the straight path 28 appear to overlap each other when viewed from above. On the other hand, the rollers placed on the saddle buffer path P2 appear offset from each other when viewed from above because the transport path is curved, and this is illustrated in the diagram.

[0119] Figure 24(a) shows the state after sheet S1 has been discharged from image forming apparatus A. At this time, the central axis of sheet S1 is not normally located at the center in the width direction, and a lateral registration error has occurred. Figure 24(b) shows the state after sheet S1 has been transported to just before the shift roller 201. At this time, the registration detection sensor 100 detects the lateral registration error of sheet S1.

[0120] Figure 25(a) shows the state after the lateral register error detection of sheet S1 by the register detection sensor 100 has finished. Figure 25(b) shows the state after sheet S1 has been transported to a position beyond the shift roller 202. At this time, the nip of the entrance roller 29 is released. In other words, sheet S1 is nipped by the shift roller 201 and the shift roller 202. The shift roller 201 and the shift roller 202 can be shifted by the transport roller shift mechanism described above.

[0121] Figure 26(a) shows that the shift rollers 201 and 202 perform lateral adjustment so that the central axis of the sheet S1 in the transport direction is aligned with the center. This corresponds to the state shown in Figure 16(b). Figure 26(b) shows the state after the sheet S1 has been transported past the intermediate transport roller 203. At this time, the inlet roller 29 is in a nip state and is ready to receive subsequent sheets.

[0122] Figure 27(a) shows the shift roller 201 returned to its original position (receiving position). Figure 27(b) shows the sheet S1 being transported in reverse to the saddle buffer path P2 by the intermediate transport roller 203, shift roller 202, buffer roller 302a, and buffer roller 302b. That is, in the state shown in Figure 27(b), the intermediate transport roller 203 and shift roller 202 are controlled to operate in reverse. At this time, the upper flapper 33a and lower flapper 33b are in the state shown in Figure 18(a).

[0123] Figure 28(a) shows the state after the shift roller 202 has been returned to its original position (receiving position). Figure 28(b) shows the state after the sheet S2 is discharged from the image forming apparatus A and has been transported to a position beyond the shift roller 201. At this time, the central axis of the sheet S2 is not located at the center in the width direction, and a lateral registration error has occurred.

[0124] Figure 29(a) shows the state in which the register detection sensor 100 detects the lateral register error of sheet S2. Figure 29(b) shows the state in which the register detection sensor 100 has finished detecting the lateral register error of sheet S2 and sheet S2 has been transported further in front of the shift roller 202.

[0125] Figure 30(a) shows the state in which the lateral registration of sheet S1 located in the saddle buffer path P2 has been adjusted to match the lateral registration error of sheet S2 by the shifting operation of buffer rollers 302a and 302b. In other words, the first shift operation for sheet S1 is performed. This corresponds to the state in Figure 21(a). Buffer rollers 302a and 302b can be shifted by the transport roller shift mechanism described above. Figure 30(b) shows the state in which sheet S1 and sheet S2 are transported synchronously to the downstream side of the straight path 28.

[0126] Figure 31(a) shows the state where sheets S1 and S2 have been transported in sync to a position beyond the shift roller 202. At this time, the nip of the inlet roller 29 is released. In other words, sheet S2 is overlapping with sheet S1 and is nipped by shift rollers 201 and 2022. Figure 31(b) shows the state where the lateral register adjustment has been performed to center sheets S1 and S2 by the shifting operation of shift rollers 201, 202 and buffer rollers 302a and 302b. This corresponds to the state in Figure 21(b). In other words, a second shift operation is performed on sheet S1.

[0127] Figure 32(a) shows the state in which sheets S1 and S2 are stacked on top of each other and transported beyond the intermediate transport roller 203. Figure 32(b) shows the state in which the shift roller 201 has been moved back to its original position (receiving position). At this time, the upper flapper 33a and the lower flapper 33b have been moved to a position where they can guide the sheets onto the saddle path 32, as shown in Figure 22(b).

[0128] Figure 33(a) shows the state in which sheets S1 and S2 are stacked and transported to the saddle path 32. Figure 33(b) shows the state in which the shift roller 202 has been moved back to its original position (receiving position).

[0129] Thus, according to this embodiment, the registration error of each sheet discharged from the image forming apparatus A and continuously received into the straight path 28 can be adjusted.

[0130] Figures 34A to 34D are flowcharts showing the buffer operation of a sheet performed in the sheet processing device B. The processing shown in Figures 34A to 34D is achieved, for example, by the binding processing control unit 95 reading a program stored in the ROM 96 into the RAM 97 and executing it. In this embodiment, the binding processing control unit 95 is a single control unit, but it may also be a combination of individual control units corresponding to each roller, etc.

[0131] In S201, sheet S1 is discharged from image forming apparatus A. The process in S201 is performed in image forming apparatus A. In S202, the binding processing control unit 95 moves the sheet support to the operating position. The sheet support is a component that prevents the sheet from falling as it is being transported along the straight path 28. In S203, the binding processing control unit 95 detects that sheet S1 has reached the entrance roller 29. In S204, the binding processing control unit 95 detects the lateral register error of sheet S1 using the register detection sensor 100.

[0132] In S205, the binding control unit 95 separates the entrance roller 29 (nip release). This is to adjust the lateral registration of the sheet S1 in a later stage by the shifting operation of the shift roller 201 and the shift roller 202. In S206, the binding control unit 95 starts the shifting operation of the shift roller 201 and the shift roller 202. Here, the shifting direction is in the direction that eliminates the lateral registration error of the sheet S1. In S207, the binding control unit 95 accelerates the sheet S1 and transports it to the downstream side of the straight path 28. In S208, the binding control unit 95 completes the shifting operation of the shift roller 201 and the shift roller 202.

[0133] In S209, the binding control unit 95 returns the inlet roller 29 to the nip position. In S210, the binding control unit 95 returns the shift roller 201 to its original position (receiving position). This corresponds to the state shown in Figure 27(a).

[0134] In S211, the binding process control unit 95 starts moving the upper flapper 33a to the buffer path guide position, and in S212, it starts moving the lower flapper 33b to the buffer path guide position. In S213, the binding process control unit 95 completes the movement of the upper flapper 33a to the buffer path guide position, and in S214, the binding process control unit 95 completes the movement of the lower flapper 33b to the buffer path guide position. This corresponds to the state shown in Figure 18(a).

[0135] In S215, the binding control unit 95 stops the shift roller 202 and the intermediate transport roller 203. In S216, the binding control unit 95 reverses the operation of the shift roller 202 and the intermediate transport roller 203 to transport the sheet S1 in reverse. In S217, the binding control unit 95 starts moving the lower flapper 33b back to its original position (receiving position). In S218, the binding control unit 95 moves the sheet S1 to the buffer path P2. In S219, the binding control unit 95 completes the movement of the lower flapper 33b back to its original position. This corresponds to the state shown in Figure 19(b). In S220, the binding control unit 95 moves the shift roller 202 back to its original position (receiving position). This corresponds to the state shown in Figure 28(a).

[0136] In S221, sheet S2 is discharged from image forming apparatus A. The process in S221 is performed in image forming apparatus A.

[0137] In S222, the binding control unit 95 detects the lateral registration error of sheet S2 using the registration detection sensor 100. In S223, the binding control unit 95 adjusts the lateral registration of sheet S1 located in the saddle buffer path P2 to match the lateral registration error of sheet S2 by shifting the buffer rollers 302a and 302b.

[0138] In S224, the binding control unit 95 separates the entrance roller 29 (nip release). This is so that in a later stage, the shifting operation of the shift rollers 201 and 202 and the buffer rollers 302a and 302b will adjust the lateral register of sheets S1 and S2.

[0139] In step S225, the binding processing control unit 95 stacks sheet S1 and sheet S2 and transports them to the shift roller 202.

[0140] In S226, the binding control unit 95 performs register adjustments to align the central axis of sheet S1 with the center by shifting the buffer rollers 302a, 302b and the shift roller 202. Meanwhile, in S227, the binding control unit 95 performs register adjustments to align the central axis of sheet S2 with the center by shifting the shift rollers 201 and 202. The processes in S226 and S227 are performed simultaneously and in parallel.

[0141] In S228, the binding control unit 95 returns the inlet roller 29 to the nip position. In S229, the binding control unit 95 returns the shift roller 201 to its original position (receiving position). This corresponds to the state shown in Figure 32(b).

[0142] In S230, the binding process control unit 95 starts moving the lower flapper 33b to the saddle path guide position, and in S231, it starts moving the upper flapper 33a to the saddle path guide position. In S232, the binding process control unit 95 completes the movement of the lower flapper 33b to the saddle path guide position, and in S233, it completes the movement of the upper flapper 33a to the saddle path guide position. This corresponds to the state shown in Figure 22(b).

[0143] In S234, the binding processing control unit 95 reverses the operation of the intermediate transport roller 203 and the shift roller 202 to stack sheets S1 and S2 and transport them in reverse to the saddle path 32.

[0144] The overlapping operation of sheets S1 and S2 shown in Figures 20(b) to 21(a) will be described in detail below. The leading edge of sheet S1 in the transport direction is positioned upstream of the nip point of the shift roller 202 in the transport direction. This is because if the merging of sheets S1 and S2 were to occur at or downstream of the nip point of the roller that overlaps and nips them, sheet S1 would come into contact with sheet S2, hindering transport and potentially preventing the merging. In particular, in bookbinding processes, a paper type with a high basis weight (for example, 256 g / m² basis weight) is used for the cover. 2 ), the inner pages are often made of a paper with a lower basis weight than the cover, and the basis weight commonly used for inner pages is 52-82 g / m². 2 With the following thin papers, the paper lacks stiffness and is prone to bending, making it more difficult to join them together.

[0145] After overlapping sheets S1 and S2, sheet S1 is buffered in the saddle buffer path P2 so that it can be nipped by the roller pair. The motors driving the transport rollers and the motors driving the buffer rollers are adjusted so that sheet S2 and sheet S1 move at approximately the same speed, and sheet S1 and sheet S2 are brought together.

[0146] Specifically, for example, using the detection results of the inlet sensor Se1 and other sheet position sensors (not shown), the leading edge of sheet S1 is positioned approximately 3 mm into the saddle buffer path P2 from the straight path 28, that is, at a position where the leading edge of sheet S1 is not exposed on the straight path 28. Just before the leading edge of sheet S2 arrives at the shift roller 202, sheet S1 is accelerated to the transport speed of sheet S2 and merged on the straight path 28. This prevents damage caused by contact between sheets and allows sheets S1 and S2 to merge smoothly.

[0147] In S235, the binding control unit 95 moves the upper flapper 33a back to its original position (receiving position), and in S236, the binding control unit 95 moves the lower flapper 33b back to its original position (receiving position).

[0148] In S237, the binding control unit 95 performs saddle processing on sheets S1 and S2 that have been fed into the leading edge regulating stopper 67. This corresponds to the processing in S109 to S111 in Figure 15. In S238, the binding control unit 95 stores the saddle-processed sheets S1 and S2 into the second tray 61 via the saddle discharge path 68 (discharge section). After that, the processing in Figures 34A to 34D is completed.

[0149] The following describes the differences in buffer operation between small and large sheets, where the length in the sheet transport direction is longer than that of small sheets.

[0150] Figures 35A to 35D are flowcharts showing the buffer operation of large-sized sheets performed in the sheet processing device B. The processing in Figures 35A to 35D is achieved, for example, by the binding processing control unit 95 reading a program stored in ROM 96 into RAM 97 and executing it. The processing in Figures 35A to 35D differs from that in Figures 34A to 34D in that the processes S303, S307, S311, S324, and S331 are performed. The processing in S301, S302, S304-S306, S308-S310, S312-S323, S325-S330, and S332-S341 is the same as the explanation in S201, S202, S203-S205, S206-S208, S210-S221, S222-S227, and S229-S238, so those explanations are omitted.

[0151] In S303, the binding processing control unit 95 moves the upper transport path flapper 34 to the upper transport path guide position. This creates a path in which the sheets being transported on the straight path 28 are guided to the upper transport path 30. When the trailing edge of a small-sized sheet passes the shift roller 202, the leading edge will be located near the paper discharge roller 36. However, when the trailing edge of a large-sized sheet passes the shift roller 202, the leading edge may protrude outside the device. In that case, it may cause the sheet to twist or break. Therefore, in this embodiment, in the case of a large-sized sheet, as shown in Figures 36(a) to 39(b), the sheet can be transported on the upper transport path 30 to prevent the twisting and breakage of the sheet as described above. Note that the states in Figures 36(a) and 36(b) correspond to the states in Figures 17(a) and 17(b) for small-sized sheets. The state in Figure 37 corresponds to the state in Figure 18(a) for small-sized sheets. The states in Figures 38(a) and 38(b) correspond to the states in Figures 22(a) and 22(b) for small-sized sheets. The states in Figures 39(a) and 39(b) correspond to the states in Figures 32(a) and 32(b) for small-sized sheets. In the buffer operation for large-sized sheets, the detection result of a sensor (not shown) provided on the upper transport path 30 may be used to detect the position of the sheet, or the inlet sensor Se1 may be used in combination to detect the position of the sheet.

[0152] In S307 and S324, the binding control unit 95 separates the intermediate transport roller 203 and the upper transport roller 303. This enables the shift rollers 201 and 202 to adjust the register size of large sheets.

[0153] In steps S311 and S331, the binding control unit 95 returns the intermediate transport roller 203 and the upper transport roller 303 to a nip state. This enables the transport of large-sized sheets.

[0154] The straight path described in this embodiment does not have to be a perfectly straight shape, and the basis weight is 500 g / m². 2It is sufficient if the coated paper exceeding a certain weight can be transported at 1750 mm / sec without damaging the sheet. Specifically, it is preferable that the curvature of the path be set to a gentle curvature that does not fall below 100R (radius of 100 mm). In addition, each pair of transport rollers will protrude from the path surface, and this protrusion is preferably about 1 mm to 2 mm from the bottom surface of the path. Note that this is for a basis weight of 500 g / m². 2 Coated paper exceeding a certain thickness is what is commonly known as cardboard, and is a type of paper used for paper packaging, magazine covers, and the like.

[0155] As described above, according to this embodiment, sheets continuously supplied from the image forming apparatus A can be buffered, stacked, and then sent to the saddle-stitching and folding processing unit.

[0156] In addition, buffering of the sheets sent to the saddle section B2 is also possible in the alternative embodiment described below. The alternative embodiment will be described with reference to Figures 40 and 41. Figure 40 shows the state in which the first sheet (preceding sheet SA) and the second sheet (subsequent sheet SB) constituting the next sheet bundle are buffered until the saddle processing of the preceding sheet bundle is completed.

[0157] The leading sheet SA is sent to the upper transport path 30, and stops and remains there once the trailing end of the leading sheet moves away from the straight path 28. Next, the following sheet SB is sent towards the paper output port 35 of the straight path, and once the trailing end of the following sheet SB in the transport direction has passed the branching point to the upper transport path 30 (flappers 34a and 34b of the upper transport bus flapper 34), it is transported in the switchback direction.

[0158] As the following sheet SB begins its switchback transport, the preceding sheet SA also begins transport toward the straight path 28. Figure 41 shows the following state where the following sheet SB and the preceding sheet SA are aligned, and after alignment, the sheet bundle is placed toward the saddle path 32.

[0159] Even with the operation of the alternative embodiment described above, up to two saddle buffers are possible.

[0160] As shown in Figure 2, the sheet post-processing device B described above has a saddle buffer path P2. However, depending on the purpose, the sheet post-processing device B may be configured without a saddle buffer path P2 for the sheets. In such a sheet post-processing device B, multiple sheets are not transported to the saddle section B2 stacked on top of each other, but rather each sheet is transported to the saddle section B2 without being moved to the saddle buffer path P2. Specifically, for example, as shown in Figure 18(a), the leading edge of the sheet is transported past the paper discharge roller 36 and then switched back, but it is transported to the saddle section B2 without being moved to the saddle buffer path P2. The following describes such a sheet post-processing device B (referred to as the second sheet post-processing device B). For convenience, the sheet post-processing device B described above will be referred to as the first sheet post-processing device B.

[0161] The sheet transport operation within the second sheet processing device B will be explained below with reference to Figures 42 to 52. Figures 42 to 52 show cross-sectional views of the second sheet processing device B as seen from the side.

[0162] Figure 42 shows the configuration near the straight path 28 in the second sheet post-processing device B. Figure 42 also shows the state in which the leading edge of the sheet ST discharged from the external image forming apparatus A to the first transport roller 201 via the straight path inlet 26, and the leading edge is detected by the inlet sensor Se1 at this time. The first transport roller 201 (first transport position) is a roller pair consisting of an upper roller 201a (first roller) and a lower roller 201b (second roller), and is collectively referred to as the first transport roller 201. The second transport roller 202 (second transport position) is a roller pair consisting of an upper roller 202a (third roller) and a lower roller 202b (fourth roller), and is collectively referred to as the second transport roller 202. The second sheet post-processing device B differs from the first sheet post-processing device B in at least the following respects.

[0163] Firstly, the second sheet post-processing device B lacks a saddle buffer path P2.

[0164] Secondly, since the second sheet post-processing device B does not have a saddle buffer path P2, the upper flapper 33a does not move to the buffer path guide position as shown in Figure 17(b). That is, the upper flapper 33a can move between a position for transporting the sheet along the straight path 28 as shown in Figure 42 and a position for transporting the sheet to the saddle section B2 via the saddle path 32 as shown in Figure 44. The saddle path 32 is, in other words, a branch path or buffer path that branches off from the straight path 28 to the saddle section B2. The upper flapper 33a is configured to change (switch) the sheet transport path between the straight path 28 and the saddle path 32.

[0165] Thirdly, since the second sheet post-processing device B does not have a saddle buffer path P2, the lower flapper 33b does not move to the buffer path guide position as shown in Figure 18(a), but is fixed in a position for transporting the sheet to the saddle section B2 as shown in Figure 42. Furthermore, the lower flapper 33b is fixed by a spring member 421 so that the user can push it down further by hand.

[0166] Fourthly, since the second sheet post-processing device B does not move the sheets to the saddle buffer path P2, the upper rollers 201a and 202a of the first and second conveyor rollers 201 and 2022 are not driven. For this reason, in this embodiment, the first and second conveyor rollers 201 and 202 are also referred to as one-sided driven conveyor roller pairs. The third conveyor roller 203 is a roller pair consisting of an upper roller 203a and a lower roller 203b, and is collectively referred to as the third conveyor roller 203. The third conveyor roller 203 may be used when conveying a bundle of sheets processed by the processing device B1. In this case, there may be intermediate layer sheets that do not come into contact with both the upper and lower rollers, such as in a bundle of three sheets. In order to convey multiple sheets of a bundle of sheets synchronously, it is necessary to transmit drive from a drive source such as a motor to both the upper roller 203a and the lower roller 203b of the third conveyor roller 203. In Figure 42, the drive gear pair 422 is shown together with the third conveyor roller 203, indicating that the third conveyor roller 203 is configured so that both the upper roller 203a and the lower roller 203b are driven. Therefore, in this embodiment, the third conveyor roller 203 is also referred to as a double-sided driven conveyor roller pair. The drive gear pair 422 consists of an upper drive gear 422a and a lower drive gear 422b, and is collectively referred to as the drive gear pair 422.

[0167] Fifthly, in the second sheet post-processing device B, the sheet removal guide 423 is configured to allow the upper rollers 201a and 202a of the first conveyor roller 201 and the second conveyor roller 202, as well as the upper flapper 33a and the roller 424, to move upward on the straight path 28. The roller 424 is a roller provided on the upper conveyor path 30 between the third conveyor roller 203 and the upper conveyor roller 303 to support the conveyance of the sheet. The roller 424 is provided to prevent the sheet from being pressed against the curved portion of the upper conveyor path 30 and damaged if the sheet is pulled between the third conveyor roller 203 and the upper conveyor roller 303.

[0168] Here, we will explain the sheet removal guide 423.

[0169] The sheet removal guide 423 is a mechanism that allows the user to easily access and remove a jammed sheet (stagnant sheet) when a sheet is straddled between the straight path 28 and the transport path to the saddle section B2. The sheet removal guide 423 is configured such that at least the upper rollers 201a (first roller) and 202a (third roller) of the first transport roller 201 (first nip position) and the second transport roller 202 (second nip position), the upper flapper 33a and the roller 424 are all movable upwards on the straight path 28. For example, the upper rollers 201a and 202a of the first transport roller 201 and the second transport roller 202, the upper flapper 33a and the roller 424 are connected to each other by a frame or the like so that they can be linked together.

[0170] Figure 53(a) shows the sheet removal guide 423 as viewed from the upstream side in the transport direction of the straight path 28. The sheet removal guide 423 is a rotating part (oscillating part) that is rotatable (oscillating) in the direction of arrow A, with a hinge 530 located on the rear side in the direction perpendicular to the transport direction of the straight path 28 (front-rear direction) as the pivot point. The sheet removal guide 423 is also provided with a reference hole 420a, and a positioning pin 420b is inserted into the reference hole 420a, and the sheet removal guide 423 is fixed to the lower housing by a latch 420c, thereby maintaining the position of the sheet removal guide 423 without displacement. In another embodiment, it is also possible to configure the sheet removal guide 423 to be equipped with this positioning pin 420b. In Figure 42, the sheet removal guide 423 is fixed by the latch 420c. Note that the latch 420c is omitted in Figures 42 and later. Figures 53(a) and 53(b) show the upper roller 201a and lower roller 201b of the first conveyor roller 201. Although not shown, a second conveyor roller 202 exists downstream in the conveying direction.

[0171] Figure 53(b) shows the sheet removal guide 423 rotated in the direction of arrow A. When a sheet jams between the straight path 28 and the transport path to the saddle section B2, the user can manually rotate the sheet removal guide 423 in the direction of arrow A by holding the reference hole 420a portion of the sheet removal guide 423. This causes the latch 420c to disengage from the lower housing, opening the front side of the second sheet post-processing device B. In this embodiment, as shown in Figure 53(b), the upper rollers 201a and 202a of the first transport roller 201 and the second transport roller 202 (not shown), as well as the upper flapper 33a and roller 424, are all configured to move upwards on the straight path 28. As the sheet removal guide 423 rotates in the direction of arrow A, a space is created between the upper rollers 201a, 202a and the lower rollers 201b, 202b of the first and second transport rollers 201 and 202, respectively, allowing the user to reach into this space, access, and remove the jammed sheet. In other words, the position of the sheet removal guide 423 shown in Figure 53(a) is the nip position, and the position of the sheet removal guide 423 shown in Figure 53(b) is the nip release position.

[0172] In this embodiment, the sheet removal guide 423 is described as being rotatable by a hinge 530, but other configurations are also possible as long as the upper rollers 201a and 202a of the first conveyor roller 201 and the second conveyor roller 202, the upper flapper 33a and the roller 424 are all movable upwards on the straight path 28. For example, the sheet removal guide 423 may be configured to slide vertically upwards.

[0173] Figure 43 shows the state where the rear end of the sheet ST has been conveyed to the upper flapper 33a. In Figure 43, the front end of the sheet ST is shown being conveyed to the third conveyor roller 203, but depending on the sheet size, it may reach the paper discharge roller 36. Note that the display of the drive gear pair 422 is omitted from Figure 43 onward.

[0174] Figure 44 shows the upper flapper 33a in a position for transporting the sheet ST to the saddle section B2. The movement of the upper flapper 33a creates a path for transporting the sheet ST to the saddle path 32. Then, the lower roller 202b of the second transport roller 202 reverses direction, initiating switchback transport of the sheet ST toward the saddle section B2. For this reason, in this embodiment, the second transport roller 202 is also called a switchback roller. Note that the spring member 421 is not shown in Figures 44 to 48.

[0175] Figure 45 shows the state in which the leading edge of the sheet ST has been transported to the conveyor roller 450 located near the entrance of the saddle section B2. Figure 46 shows the state in which the rear end of the sheet ST has been transported to the conveyor roller 450 located near the entrance of the saddle section B2.

[0176] Figures 42 to 46 above show the operation of the second sheet post-processing device B, from receiving the sheet ST discharged from the image forming apparatus A to transporting it to the saddle section B2.

[0177] Next, we will explain what happens when a jam occurs in the second sheet post-processing device B, where the sheet ST discharged from the image forming apparatus A is received and transported to the saddle section B2, and the sheet straddles between the straight path 28 and the transport path to the saddle section B2 (i.e., the saddle path 32).

[0178] Figures 42 to 45 are the same as described above. After the state shown in Figure 45, we consider a case where the drive of the conveyor roller 450 located near the entrance of the saddle section B2 becomes out of sync with the drive of the second conveyor roller 202. For example, this would apply if the drive of the conveyor roller 450 near the entrance of the saddle section B2 stops for some reason.

[0179] Figure 47 shows a state in which the sheet ST becomes jammed in the path through which the sheet ST is transported to the saddle path 32. In the state shown in Figure 47, it is difficult for the user to access and remove the sheet ST due to the presence of the upper flapper 33a. On the other hand, the saddle section B2 may be configured to be pullable out towards the front (front side) in the drawing, so that the sheet inside the saddle section B2 can be removed or components can be replaced. If the saddle section B2 is pulled out towards the front when the sheet ST is jammed, the sheet may tear, and sheet fragments may remain inside the device. Therefore, the second sheet post-processing device B is configured to be able to perform the operations shown in Figures 48 to 52. This makes it possible for the user to easily access and properly remove the jammed sheet ST.

[0180] Figure 48 shows the upper flapper 33a in a position for transporting the sheet along the straight path 28. This allows the sheet removal guide 423 to move the upper rollers 201a and 202a of the first transport roller 201 and the second transport roller 202, as well as the upper flapper 33a and the roller 424, upwards.

[0181] Figure 49 shows the state in which the sheet removal guide 423 has moved upward by rotating in the direction of arrow A. Figure 49 corresponds to the state in Figure 53(b). As shown in Figure 49, when the sheet removal guide 423 is moved upward, the positioning pin 420b is out of the reference hole 420a. When the sheet removal guide 423 is moved upward, a space is created between the upper rollers 201a and 202a of the first conveyor roller 201 and the second conveyor roller 202 and the upper flapper 33a, and between the lower rollers 201b and 202b of the first conveyor roller 201 and the second conveyor roller 202 and the lower flapper 33b, allowing the user to insert their hand.

[0182] Figure 50 shows the state in which the user has pushed the lower flapper 33b further downward. As described above, the lower flapper 33b is always fixed in a position for transporting the sheet to the saddle section B2. However, since the lower flapper 33b is fixed by being biased upward by the spring member 421, it can be manually pushed down from above. In this embodiment, by rotating the lower flapper 33b in the direction of arrow B, the user can more easily access and remove the sheet ST that is jammed between the straight path 28 and the transport path to the saddle section B2.

[0183] Figure 51 shows the state in which the user is removing the sheet ST in the direction of arrow C. Note that if the user does not press down on the lower flapper 33b, the spring member 421 returns it to the position for transporting the sheet to the saddle section B2.

[0184] This embodiment explains that the user can more easily access and remove the sheet ST that is jammed between the straight path 28 and the transport path to the saddle section B2. As described above, the sheet removal guide 423 is moved upward, and the roller 424 is also moved upward. In other words, the roller 424 moves away from the upper transport path 30, so the user can easily access and remove the sheet that has accumulated on the upper transport path 30.

[0185] Figure 52 shows the state in which the sheet removal guide 423 has moved downward from the state shown in Figure 51. Figure 52 corresponds to the state in Figure 53(a). As shown in Figure 52, when the sheet removal guide 423 is moved downward, the positioning pin 420b is inserted into the reference hole 420a, and the sheet removal guide 423 is fixed to the lower housing by the latch 420c. By fixing the position of the sheet removal guide 423 with the positioning pin 420b, the reference hole 420a, and the latch 420c, misalignment between the upper rollers 201a and 202a of the first conveyor roller 201 and the second conveyor roller 202 and the upper flapper 33a, and between the lower rollers 201b and 202b of the first conveyor roller 201 and the second conveyor roller 202 and the lower flapper 33b can be prevented.

[0186] In the operation shown in Figures 47 to 52, the first conveyor roller 201 rotates only in the forward direction to convey the sheet ST downstream. On the other hand, the second conveyor roller 202 can rotate in the forward direction to convey the sheet ST downstream and in the reverse direction to convey the sheet ST upstream in a switchback motion. When the sheet removal guide 423 moves upward and then downward to return to its original position, the upper rollers 201a and 202a of the first conveyor roller 201 and the second conveyor roller 202, respectively, need to return to the appropriate nip position.

[0187] If the positioning pin 420b and reference hole 420a were not provided, when returning from the state shown in Figure 53(b) to the state shown in Figure 53(a), it is conceivable that a shift in the nip position would occur between the upper rollers 201a and 202a and the lower rollers 201b and 202b of the first and second conveyor rollers 201 and 202. If a shift in the nip position occurs, it can cause the sheet to become skewed. Here, the switchback conveyance of the sheet by the second conveyor roller 202 is controlled, for example, based on the length of the sheet in the conveying direction. The length of the sheet in the conveying direction corresponds to the known size of the sheet, but if the sheet becomes skewed, the length in the conveying direction changes, and the switchback conveyance of the sheet will not be performed properly. In other words, the nip position of the second conveyor roller 202 requires more precision than the nip position of the first conveyor roller 201. Therefore, in this embodiment, the positioning pin 420b and the reference hole 420a are provided so as to be closer to the second conveyor roller 202 than to the first conveyor roller 201. This prevents nip position deviation for conveyor rollers that require higher accuracy in nip position. Note that the member to which the positioning pin 420b and the reference hole 420a should be provided in proximity is not limited to the conveyor roller, but may be other types of members that require high positioning accuracy. For example, if the upper flapper 33a is the member that requires the highest positioning accuracy among the members that are moved upward by the sheet removal guide 423, the positioning pin 420b and the reference hole 420a may be provided in proximity to the flapper 33a.

[0188] In the above description, the sheet removal guide 423 is configured to move the upper rollers 201a and 202a of the first conveyor roller 201 and the second conveyor roller 202, along with the upper flapper 33a and roller 424, upwards on the straight path 28. However, other configurations are also acceptable as long as it is possible to create space above the straight path 28. For example, as shown in Figure 54, only the upper flapper 33a may be made movable in the direction of arrow A. Alternatively, for example, as shown in Figure 55(a), the lower flapper 33b may be omitted, and the member 540 may be made rotatable upwards. Figure 55(b) shows the member 540 rotating upwards in conjunction with the user's movement of rotating the sheet removal guide 423 upwards. These configurations also allow for space to be created above the straight path 28, enabling the user to easily access and properly remove jammed sheets.

[0189] Furthermore, the above explanation described the case where a jam occurs in the second sheet post-processing device B, which does not have a saddle buffer path P2, when the sheet straddles between the straight path 28 and the transport path to the saddle section B2. However, the first sheet post-processing device B, which is provided with a saddle buffer path P2, may also be configured to provide space above the straight path 28. For example, as shown in Figure 56, the upper flapper 33a may be made rotatable to a position even higher than the buffer path guide position. For example, when the binding processing control unit 95 detects a jam in the sheet, it may control the upper flapper 33a to be positioned even higher than the buffer path guide position. With such a configuration, space can be provided above the straight path 28, making it possible for the user to easily access and properly remove the jammed sheet.

[0190] Figure 42 illustrates that the third conveyor roller 203 is configured such that both the upper roller 203a and the lower roller 203b are driven together. Therefore, it is not configured to move upward by the sheet removal guide 423. However, as explained in Figure 42, the sheet bundles conveyed by the third conveyor roller 203 may contain a large number of sheets. Therefore, it is required that sheets nipped by the roller pair of the third conveyor roller 203 be removable. Accordingly, in this embodiment, the third conveyor roller 203 is configured to allow for a gap between the upper roller 203a and the lower roller 203b. With such a configuration, the user can easily access and appropriately remove jammed sheets from the third conveyor roller 203 as well.

[0191] Figures 57(a) and 57(b) show the third transport roller 203 as viewed from upstream in the transport direction of the straight path 28. In the state shown in Figure 57(a), the upper drive gear 422a and the lower drive gear 422b, as explained in Figure 42, are meshed. The lower shaft 575b rotates independently of the rotation of the cam dial 571. That is, even if the lower shaft 575b rotates, that rotation is not transmitted to the cam dial 571, and even if the user rotates the cam dial 571, that rotation is not transmitted to the lower shaft 575b. The cam dial 571 and the separation cam 572 constitute a cam mechanism. In the state shown in Figure 57(a), the upper shaft 575a is biased downward by the spring member 570. This allows nip pressure to be generated between the upper roller 203a and the lower roller 203b.

[0192] As explained in Figure 42, the third conveyor roller 203 is configured such that both the upper roller 203a and the lower roller 203b are driven, and drive gears are configured on both sides of the upper shaft 575a and the lower shaft 575b. In other words, the upper drive gear 422a and the lower drive gear 422b are configured at one end of the shaft (front side), and the upper drive gear 574a and the lower drive gear 574b are configured at the other end of the shaft (rear side). In the state shown in Figure 57(a), the upper drive gear 574a and the lower drive gear 574b are meshed.

[0193] Figure 57(b) shows the upper shaft 575a in the state where it is lifted upward by the cam mechanism. In this embodiment, the upper shaft 575a is configured such that one end (upper drive gear 422a and lower drive gear 422b) can be lifted while the other end (upper drive gear 574a and lower drive gear 574b) is fixed. As shown in Figure 49, the user moves the sheet removal guide 423 upward and then manually rotates the cam dial 571. As a result, the convex portion of the cam dial 571 comes into contact with the separation cam 572, and as a result, the upper shaft 575a is lifted upward as shown in Figure 57(b). Consequently, the upper shaft 575a is in an oblique position as shown in Figure 57(b). In the state shown in Figure 57(b), the upper drive gear 422a and the lower drive gear 422b are separated, but the upper drive gear 574a and the lower drive gear 574b remain meshed. In the state shown in Figure 57(b), a gap is created between the upper roller 203a and the lower roller 203b. Furthermore, because the sheet removal guide 423 has moved upward, a space is created above the straight path 28, allowing the user to easily access and properly remove the sheet between the upper roller 203a and the lower roller 203b of the third conveyor roller 203.

[0194] As described above, in this embodiment, as shown in Figure 57(b), the upper shaft 575a is configured such that one end can be lifted while the other end (the side with the upper drive gear 574a and the lower drive gear 574b) is fixed. If the shaft were configured to slide vertically upward, the upper drive gear and the lower drive gear at each end would separate, and when the shaft is lowered back to its original position, the upper drive gear and the lower drive gear may not mesh. In this embodiment, as described above, the configuration in which only one end is lifted prevents such a situation from occurring. Furthermore, in Figures 57(a) and 57(b), the upper shaft 575a is configured to be lifted by a cam mechanism, but other configurations are not limited to a cam mechanism as long as it is possible to lift the upper shaft 575a. For example, the upper shaft 575a could be configured so that the user can lift it by holding the outer part of the upper drive gear 422a.

[0195] This embodiment includes the following sheet processing apparatus and image forming system. (Item 1) A transport route through which the sheets are transported from the entrance to the exit, A first roller and a second roller that transport the sheet received from the entrance toward the exit at the first transport position, Third and fourth rollers that transport the sheet conveyed by the first and second rollers toward the exit at the second transport position, A branch path that branches off from the aforementioned transport path and feeds the sheet by transporting it in the direction from the exit towards the entrance using the third roller and the fourth roller, A folding processing unit that performs folding on the sheet within the aforementioned branch path, A mechanism that separates the first roller from the second roller and the third roller from the fourth roller so that an operator can access the sheets that remain in the transport path from the front of the device, A fixing latch that fixes the mechanism such that the first roller and the second roller are in contact and the third roller and the fourth roller are in contact, The mechanism brings the first roller into contact with the second roller and the third roller into contact with the fourth roller, and includes a positioning unit that positions the mechanism before it is fixed by the fixing latch, A sheet processing apparatus characterized in that the positioning unit is provided closer to the second transport position than to the first transport position. (Item 2) The positioning unit is provided on the front side of the device in the front-rear direction of the device, relative to the transport path. The sheet processing apparatus according to item 1, characterized in that a hinge portion that pivotably supports the mechanism is provided on the rear side of the apparatus in the front-rear direction of the apparatus, relative to the transport path. (Item 3) An image forming system characterized by comprising a sheet folding processing device described in item 1 or 2, and an image forming device that feeds a sheet into the entrance. [Explanation of Symbols]

[0196] 28 Straight path: 201 Inlet rollers: 202, 203 Shift rollers: 203 Intermediate conveyor rollers: 33a Upper flapper (first flapper): 33b Lower flapper (second flapper)

Claims

1. A transport route through which the sheets are transported from the entrance to the exit, A first roller and a second roller that transport the sheet received from the entrance toward the exit at the first transport position, Third and fourth rollers that transport the sheet conveyed by the first and second rollers toward the exit at the second transport position, A branch path that branches off from the aforementioned transport path and feeds the sheet by transporting it in the direction from the exit to the entrance using the third roller and the fourth roller, A folding processing unit that performs folding on the sheet within the aforementioned branch path, A mechanism that separates the first roller from the second roller and the third roller from the fourth roller so that an operator can access the sheets that remain in the transport path from the front of the device, A fixing latch that fixes the mechanism such that the first roller and the second roller are in contact, and the third roller and the fourth roller are in contact, The mechanism brings the first roller into contact with the second roller and the third roller into contact with the fourth roller, and includes a positioning unit that positions the mechanism before it is fixed by the fixing latch, A sheet processing apparatus characterized in that the positioning unit is provided closer to the second transport position than to the first transport position.

2. The positioning unit is provided on the front side of the device in the front-rear direction of the device, relative to the transport path. The sheet processing apparatus according to claim 1, characterized in that a hinge portion that pivotably supports the mechanism is provided on the rear side of the apparatus in the front-rear direction of the apparatus, relative to the transport path.

3. An image forming system comprising a sheet folding processing device according to claim 1 or 2, and an image forming device for feeding a sheet into the entrance.

Images