Post-processing device and image forming system

Abstract

To prevent misalignment when performing a predetermined post-processing out of multiple post-processing procedures.SOLUTION: A post-processing device is configured such that it is possible to select either a bookbinding process mode (first mode) in which a saddle stitch process (first post process) is performed on a sheet P and then a center folding process (second post process) is performed, or a center folding process mode (second mode) in which a center folding process is performed on the sheet P without the saddle stitch process. And when the bookbinding process mode is selected, before the sheet P to be saddle stitched is received, the position of aligning devices 84, 85 in the transport direction is adjusted by a moving mechanism 110, and when the center folding process mode is selected, the positions of the aligning devices 84, 85 in the transport direction are adjusted by the moving mechanism 110 before the sheet P to be center-folded is received.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a post-processing device that performs post-processing on sheets, and an image forming system that includes an image forming device such as a copying machine, a printer, a facsimile, or a multifunction machine thereof, or a printing machine. [Background technology]

[0002] Conventionally, there have been known post-processing devices connected to image forming devices such as copiers and printers that perform multiple post-processing processes such as bookbinding (saddle-stitching and center-folding) on ​​sheets (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 1 discloses a technology in which, when performing bookbinding processing, the edges of sheets are aligned at a predetermined position before saddle stitching, and then the aligned sheets are moved to a processing position where the saddle stitching is performed, and the saddle stitching is performed. Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology, when performing a specific post-processing among a plurality of post-processings, the sheets are aligned at a specific position, and then the aligned sheets are moved from the specific position to the processing position, which causes a problem that the sheets are not aligned properly during the movement (misalignment), and therefore the appearance of the sheets after the post-processing is deteriorated.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a post-processing device and an image forming system in which alignment errors are less likely to occur when performing a specified post-processing among multiple post-processing processes. [Means for solving the problem]

[0006] The post-processing device of the present invention includes an alignment device that receives sheets conveyed in a predetermined conveying direction in a stackable manner and aligns the positions of the sheets in the conveying direction, and a moving mechanism that can move the sheets aligned by the alignment device in the conveying direction together with the alignment device, and is capable of selecting one of a first mode in which a saddle-stitching process is performed to stitch the centers of the sheets and then a center-folding process is performed to fold the centers of the sheets, and a second mode in which the center-folding process is performed on the sheets without performing the saddle-stitching process, a center folding processing section that performs the center folding process on the sheets is disposed upstream in the conveying direction of a center stitching processing section that performs the center stitching process on the sheets; The movement mechanism is controlled so that a position of the aligning device in the transport direction when the center-folding process is performed in the second mode is located upstream of a position of the aligning device in the transport direction when the center-folding process is performed in the first mode. Then, the center folding process is performed without moving the sheet aligned by the alignment device at that position. It is something. Effect of the Invention

[0007] According to the present invention, it is possible to provide a post-processing device and an image forming system in which alignment errors are unlikely to occur when a predetermined post-processing among a plurality of post-processings is performed. [Brief description of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a configuration diagram showing a post-processing device. [Diagram 3] FIG. 13 is a diagram showing an operation in a bookbinding mode. [Figure 4] FIG. 4 is a diagram showing the operation following that shown in FIG. [Diagram 5] 13A and 13B are diagrams illustrating a position difference of the end fences when a process is shifted from saddle stitching to center folding. [Figure 6] 4 is a flowchart showing a control process performed in the post-processing device. [Figure 7] FIG. 13 is a diagram showing a main part of a post-processing device serving as a first modified example. [Figure 8]13A and 13B are diagrams showing a sheet before folding processing and a state in which the sheet is positioned at a folding processing section according to a second modified example. [Figure 9] FIG. 13 is a diagram showing a main part of a post-processing device serving as a third modified example. [Figure 10] FIG. 13 is a diagram showing a main part of a post-processing device serving as a fourth modified example. [Figure 11] FIG. 13 is a diagram showing a main part of a post-processing device serving as a fifth modified example. [Figure 12] 13 is a flowchart showing a control performed in a post-processing device in a sixth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and the duplicated description will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming system 200 will be described with reference to FIG. In the present embodiment, the image forming apparatus 1 has a post-processing device 50 detachably installed therein, and constitutes one image forming system 200 together with the post-processing device 50 . In FIG. 1, reference numeral 1 denotes an image forming apparatus that functions as a copier, reference numeral 2 denotes an original reading unit that optically reads image information of an original D, and reference numeral 3 denotes an exposure unit that irradiates exposure light L based on the image information read by the original reading unit 2 onto a photosensitive drum 5. Also, reference numeral 4 denotes an image creating section which forms a toner image (image) on the photosensitive drum 5, reference numeral 7 denotes a transfer section (image forming section) which transfers the toner image formed on the photosensitive drum 5 onto a sheet P, and reference numeral 10 denotes an original transport section which transports the set original D to the original reading section 2. Further, 12 to 14 indicate a feeding section in which sheets P such as paper are stored, and 17 indicates a pair of registration rollers (a pair of timing rollers) that transport the sheet P toward the transfer section 7. Further, reference numeral 20 denotes a fixing device that fixes an unfixed image on the sheet P, 21 denotes a fixing roller disposed in the fixing device 20 , and 22 denotes a pressure roller disposed in the fixing device 20 . In addition, 30 indicates a double-sided conveying section which inverts the sheet P after an image has been formed on its front side and conveys it toward the image forming section, and 49 indicates an operation display panel which displays information related to the printing operation (image forming operation) and post-processing operation and allows operations to be performed. Further, 50 indicates a post-processing device that performs post-processing on sheets P discharged from the image forming device 1 and carried in, 71 to 73 indicate discharge trays on which the sheets P (or sheet stacks) after post-processing are loaded, 80 indicates a bookbinding processing device installed in the post-processing device 50, 90 indicates an end stitching device installed in the post-processing device 50, and 111 indicates a temperature and humidity sensor that detects the ambient environment (temperature and humidity) of the post-processing device 50.

[0011] With reference to FIG. 1, the operation of image forming apparatus 1 (image forming system 200) during normal image formation (printing) will be described. First, the document D is transported from the document table in the direction of the arrow in the figure by the transport rollers of the document transport unit 10, and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads image information of the document D passing above it. The optical image information read by the document reading unit 2 is converted into an electrical signal and then transmitted to the exposure unit 3 (writing unit). The exposure unit 3 then emits exposure light L, such as a laser beam, based on the image information of the electrical signal toward the photoconductor drum 5 of the imaging unit 4.

[0012] Meanwhile, in the image creating unit 4, the photosensitive drum 5 rotates clockwise in the figure, and after going through a predetermined image creating process (charging process, exposure process, and development process), an image (toner image) corresponding to the image information is formed on the photosensitive drum 5. Thereafter, the image formed on the photosensitive drum 5 is transferred onto a sheet P conveyed by a pair of registration rollers 17 in a transfer section 7 serving as an image forming section.

[0013] On the other hand, the sheet P conveyed to the transfer unit 7 (image forming unit) operates as follows. First, one of the plurality of feeding units 12 to 14 of the image forming apparatus 1 is automatically or manually selected (for example, it is assumed that the uppermost feeding unit 12 is selected). Then, the uppermost sheet of the sheets P stored in the feeding section 12 is conveyed toward the position of the conveying path K1.

[0014] Thereafter, the sheet P passes through a conveying path K1 on which a plurality of conveying rollers are arranged, and reaches the position of a pair of registration rollers 17. Then, the sheet P that has reached the position of the pair of registration rollers 17 is conveyed toward a transfer unit 7 (image forming unit) in a timed manner so as to be aligned with the image formed on the photosensitive drum 5.

[0015] After the transfer process, the sheet P passes through the position of the transfer unit 7, and then reaches the fixing device 20 via a transport path. The sheet P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. The sheet P with the fixed image is sent out from between the fixing roller 21 and the pressure roller 22 (the nip portion), and then discharged from the image forming apparatus 1.

[0016] When a "duplex print mode" is selected in which printing is performed on both sides (front and back) of the sheet P, the sheet P after the fixing process on the front side is not discharged as is as when the above-mentioned "single-sided print mode" is selected, but is guided to a duplex conveying path K2, where the conveying direction is reversed by the duplex conveying section 30, and then conveyed again toward the position of the transfer section 7 (image forming section). Then, at the position of the transfer section 7, an image is formed on the back side of the sheet P by the same image forming process as described above, and then the sheet P goes through a fixing process in the fixing device 20, passes through the conveying path, and is discharged from the image forming apparatus 1.

[0017] Here, in this embodiment, a post-processing device 50 is connected to the image forming apparatus 1, and the sheet P discharged from the image forming apparatus 1 is transported to the post-processing device 50, where post-processing is performed on the transported sheet P. 1, the post-processing device 50 in this embodiment is configured to convey the sheet P conveyed from the image forming device 1 to one of three conveying paths K3 to K5 and perform different post-processing. The first conveying path K3 is a conveying path for discharging the sheet P conveyed from the image forming device 1 directly to the first discharge tray 71 without performing post-processing. The second conveying path K4 is a conveying path for stacking the sheet P conveyed from the image forming device 1 on the internal tray 61, performing binding processing on the rear end of the sheet by the binding processing part 91 in the end stitching device 90, and discharging the processed sheet P (sheet stack PT) from the discharge opening 50b to the second discharge tray 72 by the discharge rollers 54. The third conveying path K5 is a conveying path for conveying the sheet P conveyed from the image forming device 1 to the second conveying path K4 once, switching back, and then performing saddle stitching processing at the center of the sheet by the saddle stitching processing unit 81 of the bookbinding processing device 80, or center folding processing by the center folding processing unit 87, and placing the sheet on the third discharge tray 73. The above-mentioned three transport paths K3 to K5 are switched by a switching operation (rotation) of a branch claw 75 (see FIG. 2).

[0018] 2, a first transport roller 51 and a sheet detection sensor (not shown) are provided near the entrance 50a of the post-processing device 50, and the sheet P detected by the sheet detection sensor is transported into the device 50 by the transport roller 51. Then, based on a post-processing mode previously selected by a user, a branch claw 75 rotates so that the sheet P is guided to a desired transport path K3 to K5. When a mode in which post-processing is not performed is selected, the sheet P conveyed to the first conveying path K3 is discharged by the pair of discharge rollers 53 and placed on the first discharge tray 71. On the other hand, when the user selects “perforation processing (punch processing)” on the operation display panel 49, the perforation processing section 60 performs perforation processing on the sheet P as the sheet P passes through the perforation processing section 60.

[0019] In addition, when the "sorting mode (sorting processing mode)" is selected, the sheets P transported to the second transport path K4 are transported while being shifted in the width direction by a predetermined amount for each sheet P by a pair of shift rollers 55 configured to be movable in the width direction (perpendicular to the paper surface of Figure 2), and are further transported to the discharge rollers 54 and sequentially stacked on the second discharge tray 72.

[0020] 2, a filler 82 is provided above the second discharge tray 72 so as to be rotatable about a support shaft at the upper end, and the second discharge tray 72 is configured to be movable up and down by a lifting mechanism (not shown). A sensor installed near the support shaft of the filler 82 detects a state in which the center of the sheet P in the conveying direction, which is sequentially stacked on the second discharge tray 72, contacts the filler 82, thereby recognizing the height of the sheet P stacked on the second discharge tray 72. The vertical position of the second discharge tray 72 is adjusted according to an increase or decrease in the number of sheets P stacked on the second discharge tray 72. When the vertical position of the second discharge tray 72 reaches the lower limit position, the number of sheets P stacked on the second discharge tray 72 is deemed to have reached the upper limit (full), and a stop signal is transmitted from the post-processing device 50 to the image forming device 1 to stop the image forming operation.

[0021] Furthermore, when the "end binding processing mode (end staple mode)" is selected, the sheets P transported to the second transport path K4 are stacked sequentially on the internal tray 61 without being shifted by the shift roller pair 55. Then, every time a sheet P (sheet stack PT) is placed on the internal tray 61, the sheet P is transported toward the end fence 66 by the transport rollers. As a result, the rear ends (rear ends in the transport direction) of the multiple sheets P (sheet stack PT) hit the end fence 66, and the positions of the multiple sheets P in the transport direction are aligned.

[0022] At this time, the jogger fences 68 (side fences) installed at both ends in the width direction of the internal tray 61 move in the width direction so as to sandwich the sheets P (sheet stack PT) every time a sheet P is placed on the internal tray 61 (or after a desired number of sheets P are stacked), thereby aligning the width direction position of the sheets P (sheet stack PT). Then, the end binding processing unit 91 performs binding processing on the rear end of the sheets P (sheet stack PT) whose conveying direction and width direction are aligned. Thereafter, the stapled sheets P (sheet stack PT) are transported obliquely upward along the inclined surface of the internal tray 61, and are discharged to the outside by the transport by the discharge rollers 54, and placed on the second discharge tray portion 72.

[0023] Also, when the "bookbinding mode (saddle stitching & center folding mode)" is selected, referring to FIG. 2, the sheet P is first conveyed to the second conveying path K4, and then, with its rear end sandwiched between the shift roller pair 55, the shift roller pair 55 is rotated in the reverse direction to switch back and conveyed to the third conveying path K5. The sheet P conveyed to the third conveying path K5 is then conveyed to the position of the bookbinding processing device 80 by a plurality of conveying roller pairs. Specifically, the sheet P is conveyed to a position where the center of the sheet P faces the saddle stitching processing unit 81 (a position where a conveying guide plate, not shown, functions as an internal tray). Then, after a desired number of sheets P (sheet bundle PT) are stacked at that position, the saddle stitching processing unit 81 performs a binding process (saddle stitching process) on the center of the sheet bundle PT. Thereafter, the plurality of sheets P (sheet stack PT) that have been subjected to saddle stitching are conveyed to a position where the center portion of the sheet stack PT faces the folding blade 88 by the movement of the aligning devices 84 and 85 by the movement mechanism 110. At this time, the leading edge of the sheet stack PT abuts against the end fence 84, and the position in the conveying direction is aligned. Also, each time a sheet P is placed on the internal tray (or after a desired number of sheets P are stacked), side fences 86 installed at both ends in the width direction of the internal tray move in the width direction to sandwich the sheet P (sheet stack PT), and the position in the width direction of the sheet P (sheet stack PT) is aligned. Then, with the central portion Pm (see FIGS. 3 and 4) of the sheet stack PT folded by the folding blade 88 moving leftward in FIG. 2, the sheet stack PT is pressed against the folded portion (central portion Pm) while being sandwiched and conveyed by the pair of folding rollers 89, and is subjected to folding processing (center folding processing). Thereafter, the sheet stack PT after center folding processing is conveyed by the pair of discharge rollers 59 and placed on the third discharge tray 73. Note that the third discharge tray 73, like the second discharge tray 72, is configured to be vertically movable by a lifting mechanism (not shown), and is lowered according to the number of sheets of the sheet stack PT stacked on the tray. In this way, a series of bookbinding processing modes (saddle stitching and center folding processing modes) is completed. The configuration and operation of the bookbinding device 80 will be described in more detail later with reference to FIGS. In addition, in this embodiment, in addition to the "bookbinding mode" in which the center-folding process is performed after the saddle-stitching process, a "center-folding mode" in which only the center-folding process is performed without the saddle-stitching process can be selected, which will be described in detail later.

[0024] The above-mentioned various post-processing modes are selected by the user operating the operation display panel 49 of the image forming apparatus 1. Further, in the post-processing device 50, the various modes described above are executed by the control unit 100 installed in the device (or in the image forming device 1).

[0025] The characteristic configuration and operation of the post-processing device 50 in this embodiment will be described in detail below. As previously described using Figure 2 etc., the post-processing device 50 in this embodiment is provided with a binding processing device 80 for performing binding processing (saddle stitching processing & center folding processing) on ​​sheets P (multiple sheets P) printed by the image forming device 1. The bookbinding device 80 is provided with a saddle stitching section 81, a center folding section 87, an alignment device constituted by an end fence 84 and a claw member 85, a moving mechanism 110, and the like.

[0026] 2, 3(A) to 3(C), and the like, the saddle stitching processing section 81 includes a driver 81a and a clincher 81b disposed on either side of a conveying path. The driver 81a is a portion that holds staples to be driven into a sheet stack PT consisting of a plurality of sheets P. Although not shown in the figure, the staples held by the driver 81a are sequentially supplied from a refill (staple cartridge) by a push-out tooth that moves by being driven by a drive motor. The clincher 81b faces the driver 81a through the sheet stack PT and deforms the staples driven into the sheet stack PT. Although not shown, the clincher 81b is driven by a drive motor to move in a direction toward and away from the driver 81a. As the drive motor is driven, the clincher 81b moves toward the driver 81a via the sheet stack PT and presses against the staple (which has penetrated the sheet stack PT) held by the driver 81a, crushing the tip of the roughly U-shaped staple toward the center around the bent portion. As a result, the central portion Pm of the sheet stack PT is stapled by the staple X, as shown in FIG. 3(a).

[0027] 2, 4, etc., the center-folding processing section 87 is disposed upstream in the conveying direction (upper in FIG. 3) of the saddle-stitching processing section 81. The center-folding processing section 87 is mainly composed of a folding blade 88 and a pair of folding rollers 89. As shown in Fig. 4A, the folding blade 88 is a blade-shaped member that pushes the center Pm of the sheet P (including the sheet stack PT) when performing the center folding process. The folding blade 88 is configured to be movable in the left-right direction in Fig. 4 by a moving means (not shown, for example, a rack and pinion mechanism) controlled by the control unit 100. 4A and 4B, the pair of folding rollers 89 is a pair of rollers that sandwich and transport the sheet P (including the sheet stack PT) pushed by the folding blade 88, with the center portion Pm of the sheet P being the leading edge. The pair of folding rollers 89 is configured to be rotatable in the direction of the arrow in FIG. 4 by a motor (not shown) controlled by the control unit 100. Then, as shown in Figures 4(A) and (B), the sheet stack PT is pushed into the nip of the folding roller pair 89 by the folding blade 88, while the folding roller pair 89 clamps and transports the sheet stack PT, forming a crease in the central portion Pm of the sheet stack PT, thereby performing a center folding process.

[0028] Referring to Figures 2 to 4, etc., alignment devices 84, 85 (regulating devices) are mechanisms for receiving sheets P transported in a predetermined transport direction (the direction of the arrow in Figure 3 (A)) in a stackable manner and aligning the position (posture) of the sheets P (including the sheet stack PT) in the transport direction. The alignment device mainly includes an end fence 84 and a claw member 85. The alignment devices 84 and 85 are held by the device housing so as to be movable in the conveyance direction (the up and down direction in FIGS. 2 and 3). As shown in FIG. 3A, the end fence 84 is a fence-shaped member against which the leading edge of the sheet P in the conveying direction abuts. The claw member 85 is a member that pushes (hits) the rear end in the conveying direction of the sheet P that has abutted against the end fence 84 toward the end fence 84. The claw member 85 is configured to be rotatable about a support shaft. When the sheet P passes through this position, the claw member 85 rotates to a retracted position that does not interfere with the sheet P, and when the sheets P are aligned (during the alignment process), the claw member 85 rotates to a pushing position that pushes the rear end of the sheet P. During the alignment process, the claw member 85 repeatedly rotates in forward and reverse directions at a small angle about the support shaft so as to repeatedly hit the rear end of the sheet P downward.

[0029] 2, the moving mechanism 110 is configured to be capable of moving the sheets P (including the sheet stack PT) aligned by the alignment devices 84, 85 together with the alignment devices 84, 85 in the conveying direction. More specifically, the moving mechanism 110 is configured to be able to move the end fence 84 and the claw member 85 in the conveying direction (the up-down direction in FIG. 3). The moving mechanism 110 moves the end fence 84 and the claw member 85 up and down when they are holding the sheet P (which has been aligned), and moves the end fence 84 and the claw member 85 up and down when they are not holding the sheet P. As such a moving mechanism 110, for example, a rack and pinion mechanism can be used. Furthermore, the movement mechanism 110 in this embodiment is configured to independently move the end fence 84 and the claw member 85 up and down to perform alignment processing (justification operation) on sheets P having different sizes in the transport direction. Specifically, when performing alignment processing on a sheet P having a large size in the transport direction, the movement mechanism 110 is controlled so that the distance in the transport direction between the end fence 84 and the claw member 85 is longer than when performing alignment processing on a sheet P having a small size in the transport direction.

[0030] 2, the alignment device in this embodiment is provided with a side fence 86 that moves in a width direction (perpendicular to the paper surface of FIG. 2) perpendicular to the conveying direction to align the widthwise position (posture) of the sheet P. Therefore, in this embodiment, the side fence 86 is held by the device housing so as to be movable in the up and down directions in FIG. The moving mechanism 110 in this embodiment is configured to be able to move the side fence 86 together with the end fence 84 and the claw members 85 in the conveying direction. With this configuration, the sheets P (sheet stack PT) stacked on the alignment device move up and down while maintaining a good alignment state (alignment state) in the width direction in addition to the alignment state (alignment state) in the transport direction. The side fences 86 are provided at both ends in the width direction. Each time a sheet P is placed on the aligning device (or after a desired number of sheets P are stacked), the pair of side fences 86 moves in the width direction to sandwich the sheet P (sheet stack PT), thereby aligning the position of the sheet P (sheet stack PT) in the width direction.

[0031] In this embodiment, a pair of transport rollers 83 is provided in the vicinity of the claw member 85 as shown in FIG. In this embodiment, if the pair of conveying rollers 83 interferes with the sheet P moving vertically together with the end fence 84 and the claw member 85 by the moving mechanism 110, the pair of conveying rollers 83 can also be configured to move vertically in the same manner, as shown in Figures 3(B) and (C).

[0032] Here, the bookbinding processing device 80 (post-processing device 50) in this embodiment is configured to be able to select either a first mode (alignment processing mode) in which a saddle stitching process is performed as a first post-processing on the sheets P, and then a center folding process is performed as a second post-processing, or a second mode in which a center folding process (second post-processing) is performed on the sheets P without performing a saddle stitching process (first post-processing). Hereinafter, the first mode will be referred to as the "alignment processing mode" and the second mode will be referred to as the "center-folding processing mode" for convenience. As previously explained using Figures 2 and 3, the "alignment processing mode" is a mode in which a center stapling process (a process of binding the central portions Pm of multiple sheets P) is performed on a sheet stack PT, and then a center folding process (a process of folding the central portions Pm of sheets P). On the other hand, the "center-folding mode" is a mode in which only the center-folding process is performed without the center-stitching process.

[0033] In this embodiment, when the bookbinding processing mode (first mode) is selected, the position of the alignment devices 84, 85 in the conveying direction is adjusted by the moving mechanism 110 before the sheet P to be subjected to the saddle stitching process (first post-processing) is received by the alignment devices 84, 85. That is, as shown in Fig. 3(A), the movement mechanism 110 moves the vertical positions of the end fence 84 and the claw members 85 to optimal positions (positions where the center Pm of the sheet P faces the binding position of the saddle stitching processing unit 81), and after that position is determined and fixed (movement is stopped), the alignment devices 84, 85 (saddle stitching processing unit 81) receive the sheet P. Then, the alignment devices 84, 85 (including the side fence 86) align the sheet stack PT in the conveying direction and width direction, and then the saddle stitching processing unit 81 performs saddle stitching.

[0034] Then, as shown in Figures 3(B) and (C), after the saddle-stitching process (first post-processing) is performed on the sheets P that have been received and aligned by the alignment devices 84 and 85, and before the center-folding process (second post-processing) is performed, the moving mechanism 110 moves the sheets after the saddle-stitching process together with the alignment devices 84 and 85. That is, after the saddle stitching processing unit 81 performs saddle stitching on the sheet bundle PT aligned by the end fence 84, the claw members 85, and the side fences 86, the movement mechanism 110 moves the end fence 84, the claw members 85, and the side fences 86 upward together with the sheet bundle PT so that the center Pm of the sheet bundle PT faces the tip of the folding blade 88. At this time, since the sheet bundle PT has been saddle stitched, the alignment state is hardly disturbed even if it moves upward as if pushed by the end fence 84. Then, as shown in Figures 4(A) and (B), the central portion Pm of the sheet stack PT is folded by the folding blade 88 moving to the left in Figure 4, and the folded portion (central portion Pm) is clamped, conveyed, and pressed by a pair of folding rollers 89 with the folded portion (central portion Pm) at the front, thereby performing a center folding process on the sheet stack PT. As described above, Fig. 5 shows the position difference W (height difference) of the end fence 84 when the process shifts from saddle stitching to center folding. That is, the end fence 84 is located at the position shown by the dashed line in Fig. 5 during saddle stitching, and is located at the position shown by the solid line in Fig. 5, which is a distance W above the original position, during center folding.

[0035] In contrast, in this embodiment, when the center folding processing mode (second mode) is selected, the position of the alignment devices 84, 85 in the conveying direction is adjusted by the moving mechanism 110 before the sheet P to be subjected to the center folding processing (second post-processing) is received by the alignment devices 84, 85. That is, as shown in Fig. 3C, the movement mechanism 110 moves the end fence 84 and the claw members 85 in the vertical direction to optimal positions (positions where the center Pm of the sheet P faces the folding position of the center-folding processing unit 87), and after that position is determined and fixed (movement is stopped), the alignment devices 84, 85 (center-folding processing unit 87) receive the sheet P. Then, the alignment devices 84, 85 (including the side fence 86) align the sheet stack PT in the conveying direction and width direction, and the center-folding processing unit 87 performs center-folding.

[0036] In this manner, in the present embodiment, when the center-folding processing mode is performed, the sheet bundle PT is aligned at the processing position (position in FIG. 3A) for the center-stitching processing and then moved to the processing position (position in FIG. 3C) for the center-folding processing. Instead, Centerfold The sheet stack PT is aligned at the processing position when processing is performed, and then the center folding process is performed in that state. Therefore, it is possible to reduce the problem (misalignment) that the sheet stack PT becomes not neatly aligned while the sheet stack PT that was once aligned is being moved to the processing position. That is, when only center folding is performed without saddle stitching, if the sheet bundle PT aligned at the processing position for center folding is moved to the processing position for center folding, the movement will cause alignment errors. In contrast, in this embodiment, when only center folding is performed without saddle stitching, the sheet bundle PT aligned at the processing position for center folding is not moved, so alignment errors are less likely to occur (good alignment state is achieved). Therefore, the appearance of the sheet bundle PT after the center folding process is less likely to deteriorate. This type of control is particularly useful when only center folding is performed without center stitching (center folding mode), since the sheet stack PT is not stapled and movement can easily cause misalignment (misalignment).

[0037] Furthermore, in this embodiment, when only center folding is performed without center stapling (center folding mode), the alignment devices 84, 85 are located at the center folding processing position from the beginning, so the movement time is unnecessary compared to when the alignment devices 84, 85 are moved from the center stapling processing position to the center folding processing position. Therefore, the processing time in the center folding processing mode is shortened, and the productivity of the device is improved.

[0038] Here, in this embodiment, as described above, the positions of the aligning devices 84, 85 in the conveying direction are adjusted by the moving mechanism 110 according to the size in the conveying direction of the sheet P to be received by the aligning devices 84, 85 before the sheet P is received by the aligning devices 84, 85. Specifically, when performing alignment processing on a sheet P having a large size in the conveying direction, the moving mechanism 110 is controlled so that the distance in the conveying direction between the end fence 84 and the claw member 85 is longer than when performing alignment processing on a sheet P having a small size in the conveying direction. In this embodiment, such control according to the size of sheet P is not limited to when the alignment operation (alignment process) of alignment devices 84, 85 is performed in the alignment processing mode, but is also executed when the alignment operation (alignment process) of alignment devices 84, 85 is performed in the center folding processing mode. This makes it possible to perform post-processing without causing alignment errors, regardless of the size of the sheet P or the processing mode.

[0039] Hereinafter, the control flow relating to the above-mentioned bookbinding processing device 80 will be described with reference to the flowchart of FIG. First, when a desired printing instruction (setting conditions) is input by the user through the operation display panel 49 (see FIG. 1) (step S1), it is determined whether the bookbinding mode is set (step S2). If the bookbinding mode is selected, printing is performed in the image forming apparatus 1 based on the setting conditions input in step S1 (step S3), and the moving mechanism 110 moves the alignment devices 84 and 85 to the saddle stitching position shown in FIG. 3(A) (step S4). After that, the printed sheets P conveyed to the post-processing device 50 are received by the alignment devices 84 and 85 (step S5), and the alignment operations in the conveying direction and the width direction are performed by the alignment devices 84 and 85 (including the side fence 86) (step S6). Then, when the number of sheets P set in step S1 is stacked and aligned on the alignment devices 84 and 85, the saddle stitching processing unit 81 performs the saddle stitching process on the sheets P (sheet stack PT) (steps S7 and S8). Then, when the saddle stitching process is completed, the sheet bundle PT is moved by the moving mechanism 110 together with the aligning devices 84, 85 (including the side fence 86) to the center folding process position shown in Fig. 3(C) (step S9). Then, the center folding unit 87 performs center stitching process on the sheet bundle PT moved to the center folding process position (step S10), and the bound sheet bundle PT is discharged and stacked on the third discharge tray 73 (see Fig. 2) (step S11).

[0040] On the other hand, if the bookbinding mode is not selected in step S2, it is determined whether the center-folding mode is selected (step S12). As a result, when the center-folding processing mode is selected, printing is performed in the image forming apparatus 1 based on the setting conditions input in step S1 (step S14), and the center-folding processing is not performed, and the moving mechanism 110 moves the alignment devices 84 and 85 to the center-folding processing position shown in FIG. 3C (step S15). After that, the printed sheets P carried into the post-processing device 50 are received by the alignment devices 84 and 85 (step S16), and the alignment operations in the conveying direction and the width direction are performed by the alignment devices 84 and 85 (including the side fence 86) (step S17). Then, when the number of sheets P set in step S1 is loaded and aligned by the alignment devices 84 and 85, the center-folding processing unit 87 performs the center-folding processing on the sheets P (sheet stack PT) (step S10). After that, the sheet stack PT after the center-folding processing is discharged and stacked on the third discharge tray 73 (see FIG. 2) (step S11). If the folding mode is not selected in step S12, another process not involving the bookbinding mode or folding mode is performed based on the setting conditions input in step S1 (step S13).

[0041] <Variation 1> In the first modification, the positions of the aligning devices 84 and 85 in the conveying direction are adjusted by the moving mechanism 110 before the sheets P are received, depending on the number of sheets P received by the aligning devices 84 and 85. Fig. 7(A) is a diagram showing a state immediately before the center-folding processing unit 87 performs center-folding processing on the sheet P (sheet stack PT) whose position in the transport direction has been adjusted by the alignment devices 84, 85. At this time, as shown in Fig. 7(C), when a large number of sheets P (sheet stack PT) are received by the alignment devices 84, 85, the sheet P is hardly bent, but as shown in Fig. 7(B), when a small number of sheets P (one sheet P in the figure) are received by the alignment devices 84, 85, the sheet P is likely to bend between the guide plates that form the transport path. 7B, if the sheet P is bent and the sheet P is abutted against the end fence 84 in the same position as in FIG. 7C, the sheet P will be folded with the center portion Pm of the sheet P shifted downward. In other words, the sheet P will not be able to be folded at the center portion Pm. This phenomenon is not limited to the center folding process, but also occurs during the saddle stitching process. Therefore, in variant example 1, when the number of sheets P received by the alignment devices 84, 85 is small, the position of the end fence 84 (alignment device) is adjusted so that the processing position for center folding and binding is higher than when the number of sheets P is large. As a result, regardless of the number of sheets P, the processing position does not shift, and the bookbinding processing mode and center-folding processing mode can be performed satisfactorily. The number of sheets P received by the alignment devices 84, 85 can be determined by the control unit 100 based on information from a counter 112 (see Figure 2) that counts the number of sheets transported, or can be determined by the control unit 100 based on printing conditions input to the operation display panel 49 (see Figures 1 and 2).

[0042] <Variation 2> In variant example 2, the moving mechanism 110 is controlled so that the position in the conveying direction of the end fence 84 (alignment device) when the center folding process is performed in the center folding process mode (second mode) is upstream (above) in the conveying direction compared to the position in the conveying direction of the end fence 84 (alignment device) when the center folding process is performed in the bookbinding process mode (first mode). This is because a sheet stack PT that has not been saddle-stitched (see FIG. 8(B1)) is more prone to bending than a sheet stack PT that has been saddle-stitched (see FIG. 8(A1)) because the sheets P are not bound together. Therefore, in Modification 2, when performing the middle folding process on the sheet bundle PT without the middle binding process as shown in Fig. 8(B2), compared with the case of performing the middle folding process on the sheet bundle PT with the middle binding process as shown in Fig. 8(A2), the end fence 84 (aligning device) is adjusted in position so that the processing positions for performing the middle folding process and the binding process are higher. As a result, regardless of the presence or absence of the middle binding process, the middle folding process mode can be performed satisfactorily without the processing position shifting.

[0043] <Modification 3> As shown in Fig. 9, in the bookbinding processing apparatus 80 (post-processing apparatus 50) in Modification 3, the vertical position is fixed so that the side fence 86 does not move up and down together with the end fence 84 (aligning device). Also, in Modification 3, the middle binding processing unit 81 is installed upstream (above) of the middle folding processing unit 87. If the vertical position of the side fence 86 is fixed as in Modification 3, as can be seen by comparing Fig. 9(A) and Fig. 9(B), depending on the vertical position of the end fence 84, the vertical length S at which the side fence 86 can contact the sheet bundle PT changes (S0 < S1). And if the vertical length S at which the side fence 86 can contact the sheet bundle PT is too short, the function of the side fence 86 for aligning the position in the width direction of the sheet bundle PT cannot be fully exerted. Therefore, when fixing the position of the side fence 86 in the transport direction, it is necessary to optimize the relative position for performing the alignment process by the side fence 86 based on the relationship between the middle folding process position in the middle folding processing unit 87 and the middle binding process position in the middle binding processing unit 81.

[0044] <Modification 4> In Modification 4, at least when the middle folding process is executed in the middle folding process mode (second mode), the pushing speed V2 of the sheet P (sheet bundle PT) by the folding blade 88 is set to be equal to or higher than the transport speed V1 of the sheet P (sheet bundle PT) by the folding roller pair 89 (V1 ≤ V2). As shown in (a1) and (a2) of Figure 10(A), when center folding is performed in the bookbinding mode, the sheet stack PT to be center folded is saddle-stitched with staple X and the sheets P are bound to each other, so that good center folding can be performed without misalignment regardless of the magnitude relationship between the conveying speed V1 of the folding roller pair 89 and the pushing speed V2 of the folding blade 88. 10B, in the center-folding mode, the sheet stack PT to be center-folded is not stapled with staples X, and the sheets P are not bound together, so the appearance after center-folding varies greatly depending on the magnitude relationship between the conveying speed V1 of the folding roller pair 89 and the pushing speed V2 of the folding blade 88. Specifically, as shown in (b1) and (b2') of FIG. 10A, if the conveying speed V1 of the folding roller pair 89 is greater than the pushing speed V2 of the folding blade 88 (V1>V2), the sheet P1 of the sheet stack PT that is closest to the nip of the folding roller pair 89 is pulled into the folding roller pair 89, causing misalignment between the sheets P, resulting in a poor appearance after center-folding. In contrast, as shown in (b1) and (b2) of Figure 10(A), when the pushing speed V2 of the folding blade 88 is equal to or greater than the conveying speed V1 of the pair of folding rollers 89 (V1≦V2), the phenomenon of the sheet P1 close to the nip being pulled into the pair of folding rollers 89 as described above does not occur, there is no misalignment between the sheets P, and the appearance after the center folding process is good. For this reason, in order to avoid the trouble of making complex adjustments to the pushing speed V2 of the folding blade 88 and the conveying speed V1 of the folding roller pair 89 for each mode, it is preferable to design in advance that the pushing speed V2 of the folding blade 88 is equal to or greater than the conveying speed V1 of the folding roller pair 89.

[0045] <Variation 5> In variant example 5, the position of the alignment device (end fence 84) in the conveying direction is adjusted by a moving mechanism 110 before the sheet P is received by the alignment device, depending on at least one of the thickness, rigidity, type, and gap of the sheet P received by the alignment device 84, 85. This is because the thinner the sheet P is and the weaker the rigidity of the sheet P is, the more likely it is that the sheet P will bend. Also, the degree of bending of the sheet P varies depending on the type of sheet P and the grain of the sheet P. As shown in Fig. 11A, if a large bend occurs in the sheet stack PT between the guide plates that form the transport path, when the sheets P hit the end fence 84 in the same position as in Fig. 11B where there is no bend, the center portion Pm of the sheets P will be shifted downward when the center portion Pm of the sheets P is folded. In other words, the center portion Pm of the sheets P cannot be folded. This phenomenon is not limited to center folding, but also occurs during saddle stitching. Therefore, in variant example 5, when the thickness of the received sheet P is thinner than a predetermined value, when the stiffness of the received sheet P is less than a predetermined threshold value, when a particular type of sheet P is received, or when a sheet P formed with a particular gap is received, the position of the end fence 84 (alignment device) is adjusted so that the processing position for center folding and binding is higher than in other cases. As a result, regardless of the thickness, stiffness, type, and gap of the sheets P, the processing position does not shift, and the bookbinding processing mode and center-folding processing mode can be performed satisfactorily. The thickness, stiffness, type and gap of the sheets P received by the alignment devices 84 and 85 can be grasped by the control unit 100 based on the printing conditions inputted to the operation display panel 49 (see FIGS. 1 and 2).

[0046] Furthermore, in the fifth modification, the position of the aligning device (end fence 84) in the conveying direction is adjusted by the moving mechanism 110 before the sheet P is received by the aligning device, depending on at least one of the ambient temperature and humidity. This is because the higher the ambient humidity is, the greater the moisture content of the sheet P is, and the higher the ambient temperature is, the more likely the sheet P is to flex. In particular, the ambient humidity has a large effect on the degree of flexure of the sheet P. Therefore, in variant example 5, when the ambient humidity is higher than a predetermined humidity or when the ambient temperature is higher than a predetermined temperature, the position of the end fence 84 (alignment device) is adjusted so that the processing position for center folding and binding is higher than in other cases. This allows the bookbinding mode and center-folding mode to be performed satisfactorily without deviation of the processing position regardless of the surrounding environment. The surrounding temperature and humidity can be grasped by the control unit 100 based on the detection results of the temperature and humidity sensor 111 (see FIGS. 1 and 2). In addition, in the fifth modification, the position of the end fence 84 (alignment device) can be finely adjusted in multiple stages according to the degree of bending of the sheet P (according to the thickness and rigidity of the sheet P, and the temperature and humidity).

[0047] <Variation 6> In variant example 6, when a binding processing mode is selected as the first mode for one sheet P, the binding processing mode (first mode) is stopped for that one sheet P and a center folding process is performed in the center folding processing mode (second mode). A user may operate the operation display panel 49 (see FIG. 1) to select an "aggregation mode" in which image information from multiple sheets of original document D is aggregated and printed on a single sheet P. In such a case, if the bookbinding mode is selected in parallel, the bookbinding mode is attempted to be performed on one sheet P, and if left as is, alignment processing is performed at the saddle stitching position (the position in FIG. 3(A)), and then the sheet is moved by the moving mechanism 110 to the center folding position and center folding processing is performed, resulting in the problems due to the movement described above (particularly the processing time). In such a case, since it is not necessary to perform saddle stitching on one sheet P, in the fifth modified example, control is performed so that the center folding mode is performed on one sheet P. Specifically, as shown in the flowchart of Fig. 12 (which adds step S20 to the flowchart of Fig. 6), the bookbinding mode is selected in step S2, and after printing is performed under set conditions (steps S1 to S3), it is determined whether the number of sheets P to be processed (number of sheets to be bound) is two or more (step S20). If the number of sheets P is two or more, the flow from step S4 onwards in the normal bookbinding mode is carried out. On the other hand, if the number of sheets P is one in step S20, the alignment devices 84 and 85 are moved to the center-folding position (step S15), and the flow from step S15 onwards in the center-folding mode is carried out.

[0048] As described above, the edge stitching device 90 and the bookbinding processing device 80 in this embodiment are provided with alignment devices 84, 85 that receive sheets P conveyed in a predetermined conveying direction in a stackable manner and align the positions of the sheets P in the conveying direction. Also provided is a moving mechanism 110 that can move the sheets P aligned by the alignment devices 84, 85 in the conveying direction together with the alignment devices 84, 85. Also, the end stitching device 90 and the bookbinding processing device 80 are configured to be able to select either one of a bookbinding processing mode (first mode) in which a center folding process (second post-processing) is performed on the sheets P after the center stitching process (first post-processing) and a center folding processing mode (second mode) in which a center folding process is performed on the sheets P without the center stitching process. When the bookbinding processing mode is selected, the positions of the aligning devices 84, 85 in the conveying direction are adjusted by the moving mechanism 110 before the sheet P to be center-stitched is received, and when the center-folding processing mode is selected, the positions of the aligning devices 84, 85 in the conveying direction are adjusted by the moving mechanism 110 before the sheet P to be center-folded is received. This makes it difficult for alignment errors to occur when performing a predetermined post-processing among a plurality of post-processings (saddle stitching and center folding).

[0049] In this embodiment, the present invention is applied to a post-processing device 50 connected to a monochrome image forming apparatus 1, but the present invention can naturally also be applied to a post-processing device connected to a color image forming apparatus. Furthermore, in this embodiment, the present invention is applied to a post-processing device 50 connected to an electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and the present invention can naturally be applied to post-processing devices connected to other types of image forming apparatus (for example, an inkjet image forming apparatus, a stencil printer, etc.). Furthermore, the present invention can be applied not only to post-processing device 50 connected to image forming device 1, but also to a post-processing device that is a standalone device (for example, a post-processing device in which a paper feed cassette is set at the entrance 50a and an operation display panel for inputting processing modes, etc. is installed on the post-processing device itself). Even in these cases, the same effects as those of this embodiment can be obtained.

[0050] In addition, in this embodiment, the present invention is applied to post-processing device 50 that can perform end binding, sorting, saddle stitching, center folding, and punching. However, the application of the present invention is not limited to this, and the present invention can naturally be applied to a post-processing device that exclusively performs the two post-processing processes of saddle stitching and center folding. In the present embodiment, the present invention is applied to a post-processing device 50 in which the first post-processing is a saddle stitching process and the second post-processing is a center folding process. However, the post-processing device to which the present invention is applied is not limited to this, and the present invention can be applied to any post-processing device that moves the alignment device and performs the first post-processing and the second post-processing consecutively. Even in these cases, the same effects as those of this embodiment can be obtained.

[0051] It is clear that the present invention is not limited to the present embodiment, and that the present embodiment may be modified as appropriate within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and may be any number, position, shape, etc. suitable for implementing the present invention.

[0052] In this specification, the term "sheet" is defined to include not only paper but also all sheet-like members that are subject to post-processing. [Explanation of symbols]

[0053] 1 Image forming apparatus (image forming apparatus main body), 50 post-treatment device, 80 Bookbinding processing device, 81 saddle stitch processing unit, 81a driver, 81b clincher, 83 conveying roller pair, 84 End fence (alignment device), 85 Claw member (alignment device), 86 Side fence (alignment device), 87 Center-folding processing section, 88 folding blade, 89 folding roller pair, 110 movement mechanism; 200 Image forming system, P, P1 sheet, PT sheet bundle. [Prior art documents] [Patent documents]

[0054] [Patent Document 1] JP 2017-149495 A

Claims

1. an alignment device that receives the sheets conveyed in a predetermined conveying direction in a stackable manner and aligns the positions of the sheets in the conveying direction; a moving mechanism capable of moving the sheet aligned by the alignment device in the conveying direction together with the alignment device; Equipped with A first mode is a mode in which a saddle stitching process is performed to stitch the center of a sheet, and then a center folding process is performed to fold the center of the sheet, and a second mode is a mode in which the saddle stitching process is not performed on the sheet, and the center folding process is performed on the sheet, a center folding processing section that performs the center folding process on the sheets is disposed upstream in the conveying direction of a center stitching processing section that performs the center stitching process on the sheets; A post-processing device characterized in that the position of the alignment device in the conveying direction when the center folding process is performed in the second mode is controlled so that it is upstream of the conveying direction compared to the position of the alignment device in the conveying direction when the center folding process is performed in the first mode, and the center folding process is performed without moving the sheet aligned by the alignment device at that position.

2. The post-processing device according to claim 1, characterized in that, when the first mode is selected, the position of the alignment device in the conveying direction of the sheet to be subjected to the saddle stitching process is adjusted by the moving mechanism, and the sheet received and aligned by the alignment device is moved together with the alignment device by the moving mechanism after the saddle stitching process is performed on the sheet but before the center folding process is performed on the sheet.

3. 3. The post-processing device according to claim 1, wherein when a bookbinding mode is selected as the first mode for one sheet, the first mode is stopped for the one sheet and the center-folding process is performed as the second mode.

4. a folding blade that pushes the center of the sheet when performing the center folding process; a pair of folding rollers that sandwich and transport the sheet, the center portion of the sheet being pushed by the folding blade being the leading edge; Equipped with The post-processing device according to any one of claims 1 to 3, characterized in that, at least when the center folding process is performed in the second mode, the sheet pushing speed by the folding blade is set to be equal to or greater than the sheet conveying speed by the pair of folding rollers.

5. The post-processing device according to any one of claims 1 to 4, characterized in that the position of the alignment device in the transport direction is adjusted by the moving mechanism before the sheet is accepted, depending on the size in the transport direction of the sheet to be accepted by the alignment device.

6. 6. The post-processing device according to claim 1, wherein the position of the aligning device in the transport direction is adjusted by the movement mechanism before the sheets are received, depending on the number of sheets received by the aligning device.

7. A post-processing device as described in any one of claims 1 to 6, characterized in that the position of the alignment device in the conveying direction is adjusted by the moving mechanism before the sheet is accepted, depending on at least one of the thickness, rigidity, type, and gap of the sheet to be accepted by the alignment device.

8. 8. The post-processing device according to claim 1, wherein the position of the aligning device in the conveying direction is adjusted by the moving mechanism before the sheet is received, in accordance with at least one of the ambient temperature and humidity.

9. The alignment device includes: an end fence against which the leading end of the sheet in the conveying direction abuts; a claw member that pushes a rear end of the sheet in the conveying direction in a state where the sheet has abutted against the end fence toward the end fence; Equipped with 9. The post-processing device according to claim 1, wherein the movement mechanism is configured to be capable of moving the end fence and the claw member in the transport direction.

10. the alignment device includes a side fence that moves in a width direction perpendicular to the conveying direction to align a position of the sheet in the width direction, 10. The post-processing device according to claim 1, wherein the moving mechanism is configured to be capable of moving the side fence in the transport direction.

11. An image forming system comprising: an image forming apparatus that forms an image on a sheet; and a post-processing apparatus according to any one of claims 1 to 10 that performs post-processing on the sheet on which the image has been formed by the image forming apparatus.

Images