Sheet post-processing device

Abstract

To provide a sheet post-processor capable of stably loading sheets on a loading tray, regardless of existence of folding processing to the sheets to be sorted.SOLUTION: A sheet post-processor comprises a folding processing unit, a discharge unit, a loading tray, a shift unit, an alignment mechanism, and a control unit. The alignment mechanism includes a first alignment member and a second alignment member arranged at one side and the other side of sheets loaded on the loading tray. The control unit, when the sheet in which folding processing has been performed is included in the sheet sorted / loaded to / on the loading tray, for the sheet shifted to the one side on the loading tray, arranges the second alignment member to a prescribed position to perform the alignment processing by the first alignment member, and for the sheet shifted to the other side, executes a second alignment mode which arranges the first alignment member to the prescribed position to perform the alignment processing by the second alignment member, or does not execute the alignment processing.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a sheet post-processing device that performs predetermined post-processing on sheets such as paper on which images have been formed by an image forming device such as a copying machine or a printer. [Background technology]

[0002] Conventionally, sheet post-processing devices have been used that can perform post-processing such as stacking multiple sheets (paper) on which images have been formed by an image forming device such as a copier or printer, and binding the stacked sheet bundle together with staples, punching hole forming processing that punches holes (perforations) using a punch hole forming device, and folding processing that folds sheets in half or in thirds.

[0003] Such a sheet post-processing device includes a pair of discharge rollers that discharges the sheets that have been subjected to post-processing, and a stacking tray on which the sheets discharged by the pair of discharge rollers are stacked.

[0004] For example, Patent Document 1 discloses a sheet stacking device that, while aligning sheets as they are loaded onto a stacking tray, lowers the stacking tray as the number of sheets loaded increases, and when the stacking tray has descended to a predetermined position, lowers an alignment plate to perform alignment.

[0005] According to the sheet stacking device of Patent Document 1, when a curl occurs in a sheet stacked on a stacking tray, it is possible to prevent a situation in which the alignment member does not come into contact with the sheet and is unable to align the sheet, with a simple configuration. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-35641 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the configuration of Patent Document 1, the top surface of the sheets loaded on the loading tray is detected, and the loading tray is raised and lowered so that the top surface position remains constant, and alignment in the front-to-rear direction of the device (paper width direction) is performed by moving an alignment member up and down and front-to-back.

[0008] However, when stacking sheets that have been folded in three (Z-fold) or the like, a bulge may occur in the sheet downstream in the conveying direction from the detected position of the top surface of the sheet. If a sorting process (shift process) is performed in this state to discharge the sheets to multiple positions in the paper width direction, for example, when the stacking position moves from the rear shift to the front shift and an alignment member that aligns the rear side of the sheet moves from the rear shift alignment position to the front shift alignment position, the bulging sheet is pushed forward, causing a problem in which the stacking of sheets becomes disorganized.

[0009] SUMMARY OF THE PRESENT DISCLOSURE In view of the above problems, an object of the present invention is to provide a sheet post-processing device that is capable of stably stacking sheets on a stacking tray, regardless of whether or not the sheets to be sorted are folded. [Means for solving the problem]

[0010] In order to achieve the above object, a first configuration of the present invention is a sheet post-processing device including a folding processing section, a discharge section, a stacking tray, a shift unit, an alignment mechanism, and a control section. The folding processing section performs a predetermined folding process on a sheet. The discharge section discharges a sheet from a sheet discharge port. The stacking tray is stacked with the sheets discharged from the sheet discharge port. The shift unit performs a shift process to shift the discharge position of the sheet on the stacking tray in a sheet width direction perpendicular to the discharge direction. The alignment mechanism includes a first alignment member arranged on one side of the sheet width direction and reciprocating in the sheet width direction, and a second alignment member arranged on the other side of the sheet width direction and reciprocating in the sheet width direction, and includes a pair of alignment members that come into contact with the sheets stacked on the stacking tray and align the position in the sheet width direction, and an alignment drive section that drives the alignment members. The control section controls the folding processing section, the shift unit, and the alignment mechanism. The control unit is capable of executing an alignment process in which the alignment mechanism is driven to align the sheets discharged to a predetermined discharge position on the stack tray, and a sorting process in which the shift unit is driven to shift the discharge position of the sheets discharged onto the stack tray alternately between one side and the other side in the sheet width direction for each part when discharging a stack of sheets, to sort the stack of sheets. When the sheets loaded on the stack tray do not include a folded sheet, the control unit executes a first alignment mode in which the alignment process is performed by the first alignment member and the second alignment member. When the sheets loaded on the stack tray include a folded sheet, the control unit executes a second alignment mode in which the second alignment member is placed at a predetermined position and the alignment process is performed by the first alignment member for sheets shifted to one side on the stack tray, and the first alignment member is placed at a predetermined position and the alignment operation is performed by the second alignment member for sheets shifted to the other side on the stack tray, or does not execute the alignment process. Effect of the Invention

[0011] According to the first configuration of the present invention, the second alignment mode is executed in which the first alignment member is used when the folded sheet is discharged to one side of the stack tray, and the second alignment member is used when the folded sheet is discharged to the other side, or the alignment process is not executed. When the discharge position is switched to one side, the second alignment member does not move above the already discharged sheet, and when the discharge position is switched to the other side, the first alignment member does not move above the already discharged sheet. Therefore, even if the sheet bulges due to the folding process, there is no risk that the bulging portion of the sheet will get caught by the alignment member and be pushed out. Therefore, it is possible to suppress the disturbance of the stacked state of the sheets. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of an image forming system including a sheet post-processing device 30 according to an embodiment of the present invention and an image forming device 10 to which the sheet post-processing device 30 is connected. [Diagram 2] FIG. 2 is a side cross-sectional view showing the internal configuration of the sheet post-processing device 30 of the present embodiment. [Diagram 3] FIG. 3 is a partial cross-sectional view of the processing tray 35 and its periphery in FIG. [Figure 4] FIG. 2 is a perspective view showing a structure around an alignment member 51 of the paper post-processing device 30; [Diagram 5] FIG. 2 is a perspective view showing the structure of an alignment mechanism 57 of the paper post-processing device 30. [Figure 6] FIG. 6(a) is a cross-sectional view showing the structure of the first paper folding unit 60 and its surroundings in the paper post-processing device 30 of this embodiment, showing the state immediately before the paper S is folded in half, and FIG. 6(b) is a view showing the state in which the paper S is folded in half by the folding blade 67. [Figure 7] FIG. 7(a) is a cross-sectional view showing the structure around the first paper folding unit 60 of the paper post-processing device 30 of this embodiment, showing the state immediately before the first paper folding unit 60 folds the paper S in thirds, and FIG. 7(b) is a view showing the state in which the paper S is folded in thirds by the folding blade 67. [Figure 8] FIG. 2 is a block diagram showing an example of a control path of the sheet post-processing device 30 of the present embodiment. [Figure 9]A flowchart showing a first operation control example of the alignment member 51 during a sorting process in the sheet post-processing device 30 of the present embodiment. [Figure 10] FIG. 10(a) shows a state in which, when the sheet S is discharged to one side in the sheet width direction (the front side of the device) in the operation control example of FIG. 9, the second alignment member 51b is made to wait at the second position, and only the first alignment member 51a is made to reciprocate at the first position to perform the alignment process, and FIG. 10(b) shows a state in which, when the sheet S is discharged to the other side in the sheet width direction (the rear side of the device), the first alignment member 51a is made to wait at the first position, and only the second alignment member 51b is made to reciprocate at the second position to perform the alignment process, in the operation control example of FIG. [Figure 11] A flowchart showing a second operation control example of the alignment member 51 during a sorting process in the sheet post-processing device 30 of the present embodiment. [Figure 12] FIG. 12 shows a state in which the first alignment member 51a waits at a first position, the second alignment member 51b waits at a second position, and a sorting process is performed without performing an alignment process in the example of operation control shown in FIG. 11. [Figure 13] FIG. 13 is a diagram showing a state in which the first alignment member 51a and the second alignment member 51b are placed in the storage position and a sorting process is performed without performing an alignment process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of an image forming system including a paper post-processing device 30 according to one embodiment of the present invention and an image forming device 10 to which the paper post-processing device 30 is connected. Fig. 2 is a side cross-sectional view showing the internal configuration of the paper post-processing device 30 of this embodiment. Fig. 3 is a partial cross-sectional view showing the structure around the processing tray 35 in Fig. 2.

[0014] As shown in Fig. 1, the image forming apparatus 10 prints an image on a paper (sheet) based on image data input from the outside via a network communication unit (not shown) or image data read by an image reading unit 11 arranged on the upper part of the image forming apparatus 10. The image forming apparatus 10 includes a paper feed unit that feeds paper, an image forming unit that forms a toner image on the paper, a fixing unit that fixes the toner image on the paper, a first discharge roller pair and a second discharge roller pair (neither shown) that transport the paper after fixing and discharge it to a paper discharge unit and a paper post-processing device, respectively, and a main body control unit 100. The main body control unit 100 controls the operation of the image forming apparatus 10, and is configured to be able to communicate with a post-processing control unit 101 (described later) of the paper post-processing device 30, and controls the post-processing control unit 101.

[0015] The paper post-processing device 30 is used in connection with the image forming device 10, and performs post-processing such as punch hole formation (perforation), binding, and folding on the paper transported from the image forming device 10. Note that the paper post-processing device 30 is not limited to a device that performs post-processing on paper automatically transported from the image forming device 10, but may also transport paper set by a user on a tray (not shown) to a position where post-processing is possible, and perform post-processing on the paper.

[0016] As shown in Figures 2 and 3, the paper post-processing device 30 includes a punch hole forming device 33 that performs a predetermined punching process on paper, a processing tray 35 that stacks multiple sheets of paper, a stapling unit 38 that staples the bundle of papers stacked on the processing tray 35, and a first paper folding unit 60 and a second paper folding unit 90 that perform a folding process on the paper.

[0017] The paper post-processing device 30 also includes a paper entrance 36 through which paper discharged from a discharge section (not shown) of the image forming device 10 is brought in, a main discharge tray 50 (loading tray) that receives paper discharged from a main discharge outlet 37, a sub-discharge tray 40 that receives paper discharged from a sub-discharge outlet 39, a post-processing control section 101 that provides overall control of the paper post-processing device 30, various switching members, various rollers, etc.

[0018] The paper entrance 36 and the main discharge opening 37 are connected to each other via a first transport path 42. A second transport path 43 branching off from the first transport path 42 is connected to the sub-discharge opening 39. A third transport path 44 branching off from the first transport path 42 is connected to a second paper folding unit 90.

[0019] The paper carried in through the paper entrance 36 is sent downstream (to the left in FIG. 4) along the first transport path 42. In the first transport path 42, a pair of intermediate rollers 72 is disposed between the upstream end and downstream end in the paper transport direction. The pair of intermediate rollers 72 is made up of a first driving roller 721 that rotates when a driving force is applied from the transport drive unit 70 (see FIG. 8), and a first driven roller 722 that rotates following the first driving roller 721. The first driving roller 721 and the first driven roller 722 are in contact with each other with a predetermined nip pressure, forming a transport nip section 72N that nips and transports the paper.

[0020] A first paper detection unit S1 is disposed immediately downstream of the intermediate roller pair 72. The first paper detection unit S1 is a sensor that optically detects paper, and detects when the leading edge of the paper being transported on the first transport path 42 enters the intermediate roller pair 72. The first paper detection unit S1 also detects when the trailing edge of the paper being transported by the intermediate roller pair 72 has passed the intermediate roller pair 72.

[0021] At the downstream end of the first transport path 42, a pair of discharge rollers 73 (discharge section) is provided that sends the paper to the main discharge tray 50. The pair of discharge rollers 73 is made up of a second drive roller 731 that is rotated by a driving force applied from a discharge drive section 90 (see FIG. 8), and a second driven roller 732 that is rotated following the second drive roller 731. The second drive roller 731 and the second driven roller 732 are in contact with each other with a predetermined nip pressure, forming a discharge nip section 73N that nips and transports the paper. When the paper is pulled into the processing tray 35 during staple processing by the staple unit 38, the pair of discharge rollers 73 separates to release the discharge nip section 73N.

[0022] The second paper detection unit S2 is disposed immediately downstream of the discharge roller pair 73. The second paper detection unit S2 is composed of an actuator having a contact piece and a detection piece that contacts the paper discharged by the discharge roller pair 73, and a photosensor (neither shown) having a light emitting unit and a light receiving unit that are disposed opposite to each other so as to sandwich the detection piece. When the leading edge of the sheet conveyed by the intermediate roller pair 72 contacts the contact piece, the actuator rotates clockwise, and the detection piece is positioned outside the optical path from the light emitting unit to the light receiving unit. This detects that the leading edge of the paper has entered the discharge roller pair 73 and that the paper is being discharged by the discharge roller pair 73. On the other hand, when the trailing edge of the paper passes the contact piece, the actuator rotates counterclockwise, and the detection piece is positioned on the optical path from the light emitting unit to the light receiving unit. This detects that the trailing edge of the paper has passed the discharge roller pair 73.

[0023] A processing tray 35 is disposed below the first transport path 42. The processing tray 35 receives and stacks the paper transported by the pair of intermediate rollers 72 with the discharge nip portion 73N of the pair of discharge rollers 73 released. The stack of paper stacked on the processing tray 35 is stapled by the staple unit 38. The downstream end (left end in FIG. 3) of the processing tray 35 in the paper transport direction is located near the pair of discharge rollers 73, and the upstream end (right end in FIG. 3) is located below the pair of intermediate rollers 72, and the processing tray 35 is inclined downward from the downstream end to the upstream end in the paper transport direction.

[0024] The stack of paper sheets loaded on the processing tray 35 and stapled by the staple unit 38 is discharged onto the main discharge tray 50 by the pair of discharge rollers 73 with the discharge nip portion 73N restored, or by the stack discharge member 35a which moves back and forth along the paper stacking surface of the processing tray 35.

[0025] The main discharge tray 50 is provided to be movable up and down on the side (the left side in FIG. 2) of the paper post-processing device 30. The main discharge tray 50 mainly receives paper that has been folded by the first paper folding unit 60 and a stack of paper that has been stapled by the staple unit 38.

[0026] An upper surface detection sensor S3 is disposed above the main discharge tray 50, which detects the upper surface position of the paper loaded on the paper loading surface 50a of the main discharge tray 50. The upper surface detection sensor S3 is a photointerrupter sensor (PI sensor) having a detection unit in which a light emitting unit and a light receiving unit are disposed on one side and the other side in the paper width direction, respectively, and is capable of detecting the upper surface position of the paper when the optical path of the detection unit is blocked by the paper loaded on the paper loading surface 50a.

[0027] A lower limit detection sensor S4 (see FIG. 2) that detects the lower limit position of the main discharge tray 50 is disposed below the main discharge tray 50. The lower limit detection sensor S4 is a PI sensor similar to the upper surface detection sensor S3, and is capable of detecting that the main discharge tray 50 has descended to the lower limit position when the light path of the detection unit is blocked by a flag 50b protruding from the main discharge tray 50.

[0028] A pair of alignment members 51 are provided upstream of the main discharge tray 50 in the paper discharge direction. The alignment members 51 are movable in the paper width direction and in the vertical direction, and align the paper loaded on the paper loading surface 50a of the main discharge tray 50 in the width direction by abutting against the side edges of the paper in the width direction.

[0029] Specifically, recesses 52 into which the lower end of the alignment member 51 can enter are provided on both sides of the paper width direction of the paper stacking surface 50a of the main discharge tray 50. The alignment member 51 aligns the paper by moving in the paper width direction with the lower end inserted into the recesses 52 (protruding downward from the paper stacking surface 50a).

[0030] Fig. 4 is a perspective view showing the structure around alignment member 51 of paper post-processing device 30. Fig. 5 is a perspective view showing the structure of alignment mechanism 57 including alignment member 51 and alignment drive unit 115 that drives alignment member 51. As shown in Figs. 4 and 5, alignment drive unit 115 has width direction movement mechanism 115a that moves alignment member 51 in the paper width direction, up / down direction movement mechanism 115b that moves alignment member 51 in the up / down direction, light blocking member 134, angle detection sensor 142, etc., which will be described later.

[0031] As shown in Fig. 4, the alignment member 51 is held by a holder 122a provided at the bottom of the carriage 122. As shown in Fig. 5, a rotating shaft (not shown) is provided inside the holder 122a, and the alignment member 51 is rotatably supported by the rotating shaft. Also, the alignment member 51 is integrally formed with a gear portion (not shown) that is rotatably supported by the rotating shaft.

[0032] The carriage 122 is moved in the paper width direction by a width-direction movement mechanism 115a along a guide shaft 126 and a drive shaft 128 that extend in the paper width direction. The width-direction movement mechanism 115a may be composed of, for example, an endless moving belt to which the carriage 122 is attached and that extends in the paper width direction, a pulley around which the moving belt is wound, and a drive motor that rotates and drives the pulley, or may be composed of a rack that extends in the paper width direction, a pinion that is provided on the carriage 122 and engages with the rack, and a drive motor that rotates and drives the pinion.

[0033] As shown in Fig. 5, an input gear 132 and a light blocking member 134 are fixed to one end of the drive shaft 128 (the left end in Fig. 5). The input gear 132 is connected to a pulse motor 136 via a one-way member (not shown) made of a one-way gear or the like that transmits rotation only in one direction. In addition, an angle detection sensor 142 made of a PI sensor having a light emitting unit and a light receiving unit is provided near one end of the drive shaft 128. The angle detection sensor 142 detects whether the light blocking piece 134a of the light blocking member 134 opens or blocks the light path, and transmits the detection result to the post-processing control unit 101.

[0034] The drive shaft 128 is formed in a D-cut shape. The carriage 122 has a bearing portion 122b into which the drive shaft 128 is inserted. Since the bearing portion 122b is formed in a circular shape in a cross-sectional view, the drive shaft 128 rotates freely relative to the bearing portion 122b.

[0035] A gear that is axially slidable relative to the drive shaft 128 and rotates integrally with the drive shaft 128, and an intermediate gear (neither shown) that transmits the rotation of the gear to a gear portion of the alignment member 51 are provided inside the carriage 122. The carriage 122, the drive shaft 128, the pulse motor 136, the one-way member (not shown), etc. form a vertical movement mechanism 115b.

[0036] When the pulse motor 136 (see FIG. 5) rotates forward, the alignment member 51 rotates forward (upward in FIG. 5) around the drive shaft 128, and the tip of the alignment member 51 is lifted. At this time, the light blocking piece 134a of the light blocking member 134 opens the light path of the angle detection sensor 142, and then the pulse motor 136 rotates further by a predetermined number of pulses and stops, so that the alignment member 51 retreats from above the main discharge tray 50 and is placed in a storage position within the paper post-processing device 30.

[0037] When the pulse motor 136 rotates in the reverse direction from this state, the alignment member 51 rotates in the reverse direction (rotates downward in FIG. 5) due to its own weight, and the tip of the alignment member 51 moves downward. At this time, if the alignment member 51 is located in a position where it does not contact the paper S on the discharge tray 50 (a position outside the paper width direction relative to the paper stacking area), the bottom end of the alignment member 51 enters the recess 52, and the alignment member 51 is located in an alignment position (the position in FIGS. 3 and 4) where it can align the paper S.

[0038] 3, a paper pressing member 53 is disposed upstream of the main discharge tray 50 in the paper discharge direction. The paper pressing member 53 is disposed below the rotation shaft 731a of the second drive roller 731 of the discharge roller pair 73.

[0039] The paper pressing member 53 is selectively positioned by the paper pressing drive unit 116 (see Figure 8) to a pressing position where it presses from above the upstream portion of the paper stacked on the main discharge tray 50 in the discharge direction, and a retracted position where it releases the pressure on the paper.

[0040] A protruding member 55 is disposed below the processing tray 35. More specifically, the protruding member 55 is disposed below the processing tray 35 and below the discharge path of the paper discharged from the discharge roller pair 73 along the processing tray 35. The protruding member 55 is a rod-shaped member having a predetermined width in the paper width direction and extending in an arc in the paper discharge direction, and is disposed in pair in the paper width direction with a predetermined interval provided at the center of the main discharge tray 50 in the paper width direction, for example. The protruding member 55 supports the lower surface of the paper discharged from the processing tray 35 onto the main discharge tray 50 to prevent the paper from curling or turning over.

[0041] At the downstream end of the second transport path 43, a sub-discharge outlet 39 is provided to send the paper to the sub-discharge tray 40. The sub-discharge tray 40 mainly receives paper that is discharged without being subjected to post-processing by the paper post-processing device 30 and paper that has only been subjected to punching by the punch hole forming device 33.

[0042] The punch hole forming device 33 is disposed above and facing the first transport path 42, between the paper entrance 36 and the first paper folding unit 60. The punch hole forming device 33 performs a punching process on the paper transported on the first transport path 42 at a predetermined timing.

[0043] The staple unit 38 is disposed downstream of and below the first transport path 42. The staple unit 38 performs a binding process in which a plurality of sheets of paper carried into the processing tray 35 are bound together with staples.

[0044] The first paper folding unit 60 is disposed immediately upstream of the branching portion of the first conveying path 42 and the second conveying path 43. The first paper folding unit 60 performs folding processing on the paper, for example, when a user selects folding processing for one sheet of paper. A detailed configuration of the first paper folding unit 60 will be described later.

[0045] The second paper folding unit 90 is provided below the paper post-processing device 30, downstream of the third transport path 44. The second paper folding unit 90 folds the paper stack when, for example, a user selects folding processing for a paper stack consisting of multiple sheets of paper. Provided downstream of the second paper folding unit 90 are a lower discharge opening 95 that discharges the paper stack that has been folded by the second paper folding unit 90, and a lower discharge tray 97 that receives the paper stack discharged from the lower discharge opening 95.

[0046] Fig. 6 is a partially enlarged view of the periphery of the first paper folding unit 60 in Fig. 3. Below, a detailed description will be given of the configuration of the first paper folding unit 60. As shown in Fig. 6(a), the first paper folding unit 60 includes a pair of folding rollers 64, a first pair of transport rollers 65, a folding blade 67, a fixed guide 68, and a movable guide 69.

[0047] The pair of folding rollers 64 is composed of a first roller 63a and a second roller 63b. The second roller 63b is pressed against the first roller 63a with a predetermined pressure by a first pressing mechanism 80 to form a first nip portion N1. The sheet S that has passed through the first nip portion N1 is transported from the right to the left in FIG. 6(a).

[0048] The first transport roller pair 65 is composed of a first roller 63a and a third roller 63c. The third roller 63c is pressed against the first roller 63a with a predetermined pressure by a second pressing mechanism 81 to form a second nip portion N2. The paper S that passes through the second nip portion N2 is transported in a direction from the top to the bottom in FIG. 6(a) that intersects with the first direction.

[0049] A fourth roller 63d is pressed against the third roller 63c to form a second conveying roller pair 66. The fourth roller 63d is composed of two rollers divided in the axial direction (perpendicular to the paper surface of FIG. 6(a)), and each is pressed against both axial ends of the third roller 63c. A switching guide 82 is disposed between the two fourth rollers 63d. When the sheet S is not to be folded, the switching guide 82 is retracted upward (in the broken line position), so that the sheet S is conveyed horizontally along the first conveying path 42 and discharged to the main discharge tray 50 (see FIG. 2). Alternatively, the sheet S passes through the second conveying path 43 branching off from the first conveying path 42 and is discharged to the sub-discharge tray 40 (see FIG. 2).

[0050] The folding blade 67 is disposed on the opposite side (the right side in FIG. 6(a)) to the pair of folding rollers 64 across the transport path of the paper S. The folding blade 67 is supported so as to be able to swing on a support shaft 67a, and is selectively disposed at a folding position (see FIG. 6(b)) where the paper S is pushed into the first nip portion N1 to perform folding processing, and at a retracted position (see FIG. 6(a)) retracted from the folding position.

[0051] Fixed guide 68 and movable guide 69 are disposed upstream of folding roller pair 64 in the paper transport direction, and guide paper S that has passed through second nip portion N2. Fixed guide 68 is fixed between transport roller 63 and folding blade 67. Movable guide 69 is selectively disposed in a cover position (see FIG. 6(a)) that covers the outer circumferential surface of second roller 63b that constitutes folding roller pair 64, and a release position (see FIG. 6(b)) that exposes the outer circumferential surface of second roller 63b.

[0052] Next, the folding process (operation) of the sheet S by the first sheet folding unit 60 will be described with reference to Figures 6 and 7. The folding process of the sheet S is executed by the post-processing control unit 101 (see Figure 2) included in the sheet post-processing device 30 when the folding mode is selected by the user using the operation panel 12 (see Figure 2) of the image forming device 10. Also, the fourth roller 63d and the switching guide 82 are omitted from Figures 6(b) and 7.

[0053] First, a case where the sheet S is folded in half will be described. As shown in Fig. 6(a), the sheet S conveyed from the first conveying path 42 has its conveying direction switched to downward by the switching guide 82. As a result, the sheet S is conveyed along the outer circumferential surface of the third roller 63c and passes through the second nip portion N2 of the first conveying roller pair 65. Then, the conveyance of the sheet S is stopped so that the folded portion of the sheet S (the center portion in the sheet conveying direction) faces the first nip portion N1.

[0054] The timing to stop the transport of the paper S is determined based on the detection timing of the paper detection sensor 75 (see FIG. 2). Specifically, when the paper detection sensor 75 detects the leading edge of the paper S, the detection result is sent to the post-processing control unit 101. The post-processing control unit 101 controls the transport drive unit 110 (see FIG. 8) to stop the transport of the paper S a predetermined time after the leading edge of the paper S is detected. The time from when the leading edge of the paper S is detected to when the transport of the paper S is stopped is set in advance for each size of the paper S.

[0055] Next, as shown in Fig. 6(b), the movable guide 69 is moved to the release position, and the folding blade 67 is swung counterclockwise to the folding position. At this time, the folding blade 67 comes into contact with the folded portion of the sheet S. The sheet S pushed out by the folding blade 67 is pushed into the first nip portion N1 of the pair of folding rollers 64 in a bent state. A fold F is formed in the sheet S that has passed through the first nip portion N1.

[0056] The sheet S with the crease F formed thereon passes through the first transport path 42 and is discharged from the main discharge opening 37 (discharge roller pair 73) to the main discharge tray 50. Thereafter, the movable guide 69 is moved to the cover position and the folding blade 67 is moved to the retracted position to return to the state shown in FIG. 6(a). Thereafter, the sheet S is folded in half in the same manner.

[0057] Next, a case where the sheet S is folded in thirds (Z-fold) will be described. In the folding in thirds process, first, the switching guide 82 (see FIG. 6(a)) is retracted upward, and the leading edge of the sheet S conveyed along the first conveying path 42 is stopped downstream of the second nip portion N2 (left side of FIG. 7(a)) so that the first fold of the sheet S (1 / 3 position from the leading edge of the sheet) faces the second nip portion N2. The timing for stopping the conveyance of the sheet S is determined based on the detection timing of a sheet detection sensor (not shown) arranged along the first conveying path 42.

[0058] Next, the switching guide 82 is moved downward. At this time, the switching guide 82 comes into contact with the first folded portion of the sheet S. The sheet S pushed out by the switching guide 82 is pushed into the second nip portion N2 of the first transport roller pair 65 in a bent state, as shown in FIG. 7(a). A fold F1 is formed in the sheet S that has passed through the second nip portion N2. The first transport roller pair 65 functions as a folding roller pair when folding the sheet in three.

[0059] Thereafter, sheet S passes from fold F1 through second nip portion N2, and further passes between fixed guide 68 and movable guide 69. Then, transport of sheet S is stopped so that the second folded portion of sheet S (2 / 3 position from the leading edge of sheet S) faces first nip portion N1. The timing at which transport of sheet S is stopped is determined based on the detection timing of sheet detection sensor 75.

[0060] 7(b), the movable guide 69 is moved to the release position, and the folding blade 67 is swung counterclockwise to the folding position. At this time, the folding blade 67 comes into contact with the second folded portion of the sheet S. The leading edge and the bent portion of the sheet S pushed out by the folding blade 67 are both pushed into the first nip portion N1 of the pair of folding rollers 64. A fold F2 is formed in the sheet S that has passed through the first nip portion N1.

[0061] The sheet S with the folds F1 and F2 formed thereon passes through the first transport path 42 and is discharged from the main discharge opening 37 (discharge roller pair 73) to the main discharge tray 50. Thereafter, the movable guide 69 is moved to the cover position, the folding blade 67 is moved to the retracted position, and the switching guide 82 is retracted upward. Thereafter, the sheet S is folded in three in the same manner.

[0062] 8 is a block diagram showing an example of a control path of the post-sheet processing device 30. The post-processing control section 101 (hereinafter simply referred to as the control section 101) is composed of a CPU (Central Processing Unit) that controls the operation of each section of the post-sheet processing device 30, a ROM (Read Only Memory) that stores a control program, a RAM (Random Access Memory) used as a working area for the CPU, etc. The control section 101 controls the operation of each section of the post-sheet processing device 30 by the CPU executing the control program stored in the ROM.

[0063] The control unit 101 controls the punching operation by the punch hole forming device 33 and the stapling operation by the stapling unit 38. The control unit 101 controls the driving of the transport drive unit 110 to control the rotation and stopping of the second transport roller pair 66 and the intermediate roller pair 72. The control unit 101 controls the driving of the discharge drive unit 111 to control the rotation and stopping of the discharge roller pair 73.

[0064] The control unit 101 controls the driving of the nip release drive unit 112, thereby controlling the release operation and restoration operation of the discharge nip portion 73N of the discharge roller pair 73 by the nip release mechanism 113. For example, when stapling is performed by the staple unit 38 on a stack of paper sheets of a predetermined number, the control unit 101 operates the nip release mechanism 113 by the nip release drive unit 112 to release the discharge nip portion 73N after the first sheet is pulled into the processing tray 35. Then, after the second and subsequent sheets of paper are pulled into the processing tray 35 and stapled, the control unit 101 restores the discharge nip portion 73N when discharging the stack of paper sheets to the main discharge tray 50.

[0065] In addition, when discharging a stack of sheets of paper onto the main discharge tray 50 using the stack discharge member 35a, with the discharge nip portion 73N released, the stack discharge member 35a is moved downstream in the paper discharge direction to push the stack of sheets of paper onto the main discharge tray 50 and discharge it.

[0066] The control unit 101 controls the driving of the tray lifting / lowering drive unit 114 to control the lifting operation of the main discharge tray 50. The control unit 101 controls the driving of the alignment drive unit 115 to execute the sheet alignment process by the alignment member 51. The control unit 100 controls the driving of the paper pressure drive unit 116 to control the swinging operation of the paper pressure member 53 between the pressing position and the retracted position. The control unit 101 controls the driving of the protrusion drive unit 117 to control the movement of the protrusion member 55 between the protruding position and the retracted position. The control unit 101 controls the driving of the folding unit drive unit 118 to control the paper folding process operation by the first paper folding unit 60 and the second paper folding unit 90.

[0067] The control unit 101 drives the shift unit 119 to execute a sorting process (shift process) in which, when discharging a bundle of sheets S (sheet stack), the discharge position of the sheets S is shifted alternately to one side and the other side in the width direction for each copy to sort the sheet stack. The shift unit 119 includes a cursor that shifts the bundle of sheets S loaded on the processing tray 35 in the sheet width direction, and a cursor drive unit (neither shown) that moves the cursor back and forth.

[0068] In a mode in which sheets S are continuously stacked one by one on the main discharge tray 50, the top surface detection sensor S3 detects the top surface position of the stack of sheets stacked on the main discharge tray 50. Then, the main discharge tray 50 is raised and lowered (positioned) so that the top surface position of the stack of sheets remains constant. In addition, alignment of the stacked stack of sheets in the front-to-rear direction (sheet width direction) is performed by moving the alignment member 51 in the up-down and width directions.

[0069] Here, when paper S that has been folded in half or in thirds (Z-fold) is loaded onto the main discharge tray 50, a bulge larger than the top surface position detected by the top surface detection sensor S3 may occur on the downstream side of the paper S in the discharge direction.

[0070] In this state, when sorting (shifting) the sheets S, when the alignment member 51 is lifted upward and moved widthwise to switch the alignment position in response to switching of the sorting position, the alignment member 51 gets caught on the bulging part of the stacked sheets S, pushing out the sheets S. In particular, in the case of folding in three (Z-folding), the bulge becomes larger, making the above-mentioned problem more likely to occur.

[0071] Therefore, in this embodiment, when the paper S that has been folded in the first paper folding unit 60 is sorted and discharged to the main discharge tray 50, the operation of the alignment member 51 is changed to prevent improper loading of the paper S.

[0072] Fig. 9 is a flow chart showing a first operation control example of the alignment member 51 during sorting and discharging in the paper post-processing device 30 of this embodiment. The alignment operation of the alignment member 51 during the sorting process will be described along the steps of Fig. 9, with reference to Figs. 1 to 8 and Fig. 10 described later as necessary. Note that in the following description, it is assumed that during the sorting process, the paper is discharged to one side in the paper width direction (the front side of the device) and the other side (the back side of the device).

[0073] Of the pair of alignment members 51, the one arranged on one side in the paper width direction (the front side of the device) is referred to as the first alignment member 51a, and the one arranged on the other side (the rear side of the device) is referred to as the second alignment member 51b. The alignment positions (positions that contact the widthwise edge of the paper S) of the first alignment member 51a and the second alignment member 51b when the paper S is discharged to one side and the other side in the paper width direction are referred to as the first position and the second position, respectively.

[0074] When the sorting process is started (step S1), the post-processing control unit 101 determines whether or not folding process of the sheet S by the first sheet folding unit 60 is set (step S2). If folding process is set (Yes in step S2), as shown in Fig. 10(a), when the sheet S is discharged to one side in the sheet width direction (the front side of the device), the second alignment member 51b is made to wait at the second position (step S3). Then, the first alignment member 51a alone is moved back and forth between the first position and a position outside the first position to perform an alignment operation (step S4).

[0075] The post-processing control unit 101 determines whether or not a predetermined number of sheets S have been discharged (step S5). If the predetermined number has not been reached (No in step S5), the process returns to step S3, and the discharge of sheets S to one side in the paper width direction (the front side of the device) continues (steps S3, S4). If the predetermined number of sheets S have been discharged in step S5 (Yes in step S5), the post-processing control unit 101 determines whether or not the discharge of sheets S has been completed (step S6). If the discharge of sheets S has been completed (Yes in step S6), the sorting and discharge process ends.

[0076] If the discharge of the paper S continues in step S6 (No in step S6), the discharge position is switched from one side in the paper width direction (the front side of the device) to the other side (the rear side of the device). Then, as shown in FIG. 10(b), when the paper S is discharged to the other side in the paper width direction, the first alignment member 51a is made to wait at the first position (step S7). Then, only the second alignment member 51b is moved back and forth between the second position and a position outside the second position to perform an alignment operation (step S8).

[0077] The post-processing control unit 101 determines whether or not a predetermined number of sheets S have been discharged (step S9). If the predetermined number has not been reached (No in step S8), the process returns to step S7 and continues discharging sheets S to the other side in the paper width direction (the rear side of the device) (steps S7 and S8). If the predetermined number of sheets S have been discharged in step S9 (Yes in step S9), the process determines whether or not discharging of sheets S has been completed (step S10).

[0078] If the discharge of the paper S continues in step S10 (No in step S10), the discharge position is switched again from the other side to one side in the paper width direction. Then, the process returns to step S3, and the sorting process is repeated in the same manner (steps S3 to S10). If the discharge of the paper S has finished (Yes in step S10), the sorting process ends.

[0079] On the other hand, if there is no folding process in step S2 (No in step S2), the first alignment member 51a is moved back and forth between the first position and a position outer than the first position, and the second alignment member 51b is moved back and forth between the second position and a position outer than the second position to perform an alignment operation (step S11).

[0080] The post-processing control unit 101 determines whether or not a predetermined number of sheets S have been discharged (step S12). If the predetermined number has not been reached (No in step S12), the process returns to step S11 and continues discharging sheets S to one side in the paper width direction (the front side of the device). If a predetermined number of sheets S have been discharged in step S12 (Yes in step S12), the post-processing control unit 101 determines whether or not discharging of sheets S has been completed (step S13). If discharging of sheets S has been completed (Yes in step S13), the sorting process ends.

[0081] If the discharge of the paper S continues in step S13 (No in step S13), the discharge position is switched from one side to the other side in the paper width direction. Then, when discharging the paper S to the other side in the paper width direction, the first alignment member 51a and the second alignment member 51b are reciprocated between the first position and a position outside the first position, and between the second position and a position outside the second position, respectively, to perform an alignment operation (step S14).

[0082] The post-processing control unit 101 determines whether or not a predetermined number of sheets S have been discharged (step S15). If the predetermined number has not been reached (No in step S15), the process returns to step S14 and continues discharging sheets S to the other side in the paper width direction (the rear side of the device). If the predetermined number of sheets S have been discharged in step S15 (Yes in step S15), the post-processing control unit 101 determines whether or not discharging of sheets S has been completed (step S16).

[0083] If the discharge of the paper S continues in step S16 (No in step S16), the discharge position is switched again from the other side to one side in the paper width direction. Then, the process returns to step S11, and the sorting process is repeated in the same manner (steps S11 to S16). If the discharge of the paper S has finished (Yes in step S16), the sorting process ends.

[0084] 9, if the discharge of all sheets S is completed before a predetermined number of sheets S is discharged in steps S5, S9, S12, and S15, the sorting process ends at that point. Also, the alignment operation by the first alignment member 51a and the second alignment member 51b when the sheets S sorted and discharged onto the main discharge tray 50 do not include sheets S that have been folded is referred to as a first alignment mode, and the alignment operation by either the first alignment member 51a or the second alignment member 51b when the sheets S sorted and discharged include sheets S that have been folded (see FIG. 10) is referred to as a second alignment mode.

[0085] According to the first operation control example shown in Figure 9, if a folding process is set when performing a sorting process, a second alignment mode is executed in which alignment process is performed using only the alignment member 51 located outside the sorting position in the paper width direction (the first alignment member 51a when the discharge position is at the front of the device, and the second alignment member 51b when the discharge position is at the rear of the device), so that when the discharge position is switched, the alignment member 51 located inside the sorting position (the second alignment member 51b when the discharge position is switched to the front of the device, and the first alignment member 51a when the discharge position is switched to the rear of the device) does not move above the paper S that has already been discharged.

[0086] Therefore, even if the sheet S bulges due to folding, there is no risk of the bulged portion of the sheet S getting caught by the alignment member 51 and being pushed out. Therefore, it is possible to prevent the stack state of the sheets S on the main discharge tray 50 from becoming disarrayed.

[0087] In addition, when the folding process is not set, the first alignment mode is executed to perform the alignment process using both the first alignment member 51a and the second alignment member 51b, thereby ensuring that the sheets S discharged to each sorting position are aligned.

[0088] Fig. 11 is a flow chart showing a second operation control example of the alignment member 51 during the sorting process in the sheet post-processing device 30 of this embodiment. The alignment operation of the alignment member 51 during the sorting process will be described following the steps of Fig. 11, with reference to Figs. 1 to 8 and Fig. 12 described later as necessary.

[0089] When the sorting process is started (step S1), the post-processing control unit 101 determines whether or not folding process of the sheet S by the first sheet folding unit 60 is set (step S2). If folding process is set (Yes in step S2), the first alignment member 51a is made to wait at the first position (step S3) as shown in FIG. 12. Similarly, the second alignment member 51b is made to wait at the second position (step S4). Then, the sheet S is discharged to one side in the sheet width direction (the front side of the device) without performing an alignment operation of the sheet S.

[0090] The post-processing control unit 101 determines whether or not a predetermined number of sheets S have been discharged (step S5). If the predetermined number has not been reached (No in step S5), the process returns to step S3 and continues discharging the sheets S to one side in the paper width direction (the front side of the device) (steps S3 and S4).

[0091] If a predetermined number of sheets S have been discharged in step S5 (Yes in step S5), it is determined whether or not the discharge of sheets S has been completed (step S6). If the discharge of sheets S has been completed (Yes in step S6), the sorting process ends. If the discharge of sheets S continues (No in step S6), the discharge position is switched to the other side in the sheet width direction (the rear side of the device) (step S7). Then, the process returns to step S3, and sheets S are discharged without performing an alignment operation for sheets S (steps S3 to S6).

[0092] On the other hand, if there is no folding process in step S2 (No in step S2), similar to the operation control example shown in Figure 9, the first alignment member 51a is moved back and forth between the first position and a position outer than the first position, and the second alignment member 51b is moved back and forth between the second position and a position outer than the second position to perform the normal alignment operation (first alignment mode), while performing the sorting process to one side (the front side of the device) and the other side (the rear side of the device) in the paper width direction (steps S8 to S13).

[0093] According to the second operation control example shown in Fig. 11, when folding processing is set for the sheet S, the first alignment member 51a and the second alignment member 51b are made to wait at the first position and the second position, respectively, and no alignment operation is performed. Therefore, even if the sheet S bulges due to folding processing, there is no risk of the bulging portion of the sheet S getting caught by the alignment member 51 and being pushed out. Therefore, as with the first operation control example shown in Fig. 9, it is possible to prevent the stack state of the sheets S from becoming disarrayed.

[0094] In addition, since no alignment operation is performed by the first alignment member 51a and the second alignment member 51b, the loading ability (alignment) of the paper S is inferior to that of the first operation control example, but since the first alignment member 51a is positioned at the first position and the second alignment member 51b is positioned at the second position, it is possible to prevent the paper S from falling off the main discharge tray 50.

[0095] In the operation control example of Figure 11, the first alignment member 51a and the second alignment member 51b are kept waiting at the first position and the second position, respectively, as shown in Figure 12, but the waiting positions of the first alignment member 51a and the second alignment member 51b are not limited to the first position and the second position, and may be near the outside in the paper width direction of the first position and the second position.

[0096] 13, for example, the sorting process of the folded sheets S may be performed with the first alignment member 51a and the second alignment member 51b stored in the storage position in the sheet post-processing device 30. In this case, the first alignment member 51a and the second alignment member 51b do not have the effect of preventing the sheets S from falling out, but it is possible to prevent the stacked state of the sheets S from being disturbed by the alignment members 51 catching the bulging portions of the sheets S and being pushed out.

[0097] Incidentally, when sorting processing is performed with the first alignment member 51a and the second alignment member 51b stored in the storage position as shown in Fig. 13, sheet information of the first few sheets (whether or not they have been folded) is transmitted to the control unit 90 at the start of processing, but it is unclear whether sheets S that have been folded during processing will be discharged. For example, if the first few sheets do not include folded sheets S, alignment processing by the first alignment member 51a and the second alignment member 51b is possible. On the other hand, if sheet information including sheets S that have been folded during processing is transmitted, it is necessary to store the first alignment member 51a and the second alignment member 51b in the storage position.

[0098] Furthermore, during sorting, even if one set (one stack) of sheets S contains 10 sheets, the set is not shifted when 10 sheets have accumulated in processing tray 35, but is shifted into several discharge stacks of sheets (2 to 5 sheets) and discharged multiple times onto main discharge tray 50. Therefore, if the sheet information sent to control unit 90 includes sheets that have been folded, it is preferable to store first alignment member 51a and second alignment member 51b in the storage position at the timing when the discharge operation of the discharge stack that does not include sheets that have been folded is completed.

[0099] Hereinafter, a case where a set of 10 sheets of paper including folded paper S is divided into two sets of three or four sheets and discharged will be specifically described. For example, when the first and second sheets of the paper bundle include folded paper S (hereinafter, referred to as folded paper), the first alignment member 51a and the second alignment member 51b are stored in the storage position before the start of the sorting process. Then, the first discharged bundle (1st to 3rd sheets) is carried into the central reference position (widthwise center) of the processing tray 35, and is shifted to one side in the paper width direction (the front side of the device) by the shift unit 119 and discharged. Similarly, the second subsequent discharged bundle (4th to 6th sheets) is shifted to one side in the paper width direction (the front side of the device) and discharged. Then, the third discharged bundle (7th to 10th sheets) is shifted to one side in the paper width direction (the front side of the device) and discharged, completing the discharge of the first set.

[0100] Next, the second copy is discharged with the first alignment member 51a and the second alignment member 51b stored in the storage position. The procedure for discharging the second copy is the same as that for the first copy, except that the second copy is discharged by shifting it to the other side in the paper width direction (toward the back of the device) using the shift unit 119.

[0101] Furthermore, if the third or subsequent sheets in the stack of sheets contain folded sheets, the first alignment member 51a and the second alignment member 51b are protruded from the storage position onto the main discharge tray 50 before the start of the sorting process. The first discharged stack (first to third sheets) is then carried into the central reference position (center in the width direction) of the processing tray 35, and shifted to one side in the sheet width direction (toward the front of the device) by the shift unit 119 and discharged. Next, the first alignment member 51a and the second alignment member 51b are used to perform an alignment process on the first discharged stack (first to third sheets). After that, the first alignment member 51a and the second alignment member 51b are stored in the storage position.

[0102] Similarly, the second subsequent output stack (4th to 6th sheets) is shifted to one side in the paper width direction (toward the front of the device) and output. Then, the third output stack (7th to 10th sheets) is shifted to one side in the paper width direction (toward the front of the device) and output, completing output of the first set.

[0103] Next, the second copy is discharged with the first alignment member 51a and the second alignment member 51b stored in the storage position. The procedure for discharging the second copy is the same as that for the first copy, except that the second copy is discharged by shifting it to the other side in the paper width direction (toward the back of the device) using the shift unit 119.

[0104] According to the above procedure, even if folded sheets are included in the sorting process, the alignment process can be performed by the alignment member 51 up to the discharged stack immediately before the folded sheets are included. Therefore, it is possible to perform the alignment process by the alignment member 51 to the extent possible while preventing the alignment member 51 from catching the bulging portion of the sheets S and pushing them out.

[0105] Additionally, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, an example is shown in which the first paper folding unit 60 includes the folding roller pair 64 composed of three rollers, the first roller 63a to the third roller 63c, and the first transport roller pair 65, but the present invention is not limited to this, and for example, the first paper folding unit 60 may be configured to include only the folding roller pair 64 composed of the first roller 63a and the second roller 63b.

[0106] In addition, in the above embodiment, the paper post-processing device 30 is provided with a first paper folding unit 60, and the folded paper S is discharged to the main discharge tray 50 located downstream of the first paper folding unit 60. However, the paper post-processing device 30 may be configured to have a separate paper folding device (not shown) connected between the image forming device 10 and the paper post-processing device 30, and the paper that has been folded by the paper folding device be transported into the paper post-processing device 30.

[0107] In addition, in the above embodiment, a multifunction peripheral as shown in FIG. 1 is exemplified as an example of the image forming device 10, but the paper post-processing device 30 of the present invention can also be connected to image forming devices other than digital multifunction peripherals, such as laser printers, inkjet printers, facsimile machines, etc. [Explanation of symbols]

[0108] 10 Image forming device 30 Paper post-processing device (sheet post-processing device) 37 Main outlet (sheet outlet) 50 Main output tray (loading tray) 51 Alignment member 51a First alignment member 51b Second alignment member 57 Alignment mechanism 60 First paper folding unit (folding processing section) 61 Sheet access route 63a 1st Roller 63b 2nd Roller 63c 3rd Roller 63d 4th Roller 64 Folding roller pair 65 First conveyor roller pair 66 Second conveyor roller pair 67 Folding Blade 72 Switching Guide 73 Discharge roller pair (discharge section) 101 Post-processing control section (control section) S Paper (sheet) N1 First nip section N2 1st nip section F, F1, F2 folds

Claims

1. a folding processing section that performs a predetermined folding process on the sheet; a discharge section that discharges the sheet from a sheet discharge port; a stacking tray on which the sheets discharged from the sheet discharge port are stacked; a shift unit that performs a shift process to shift a discharge position of the sheet on the stack tray in a sheet width direction perpendicular to a discharge direction; an alignment mechanism including a pair of alignment members, the pair including a first alignment member disposed on one side in the sheet width direction and reciprocating in the sheet width direction, and a second alignment member disposed on the other side in the sheet width direction and reciprocating in the sheet width direction, the pair of alignment members contacting the sheets loaded on the stacking tray and aligning positions in the sheet width direction, and an alignment drive unit that drives the alignment members; A control unit that controls the folding processing unit, the shift unit, and the alignment mechanism; Equipped with The control unit is an alignment process of driving the alignment mechanism to align the sheet discharged to a predetermined discharge position on the stack tray; a sorting process in which the shift unit is driven to shift a discharge position of the sheets discharged onto the stacking tray when discharging a plurality of copies of the sheet bundle alternately to one side and the other side in the sheet width direction for each copy, thereby sorting the sheet bundle; It is possible to execute In the sorting process, When the sheets stacked on the stacking tray do not include a sheet on which the folding process has been performed, a first alignment mode is executed in which the alignment process is performed by the first alignment member and the second alignment member. When the sheets loaded on the loading tray include a sheet that has been subjected to the folding process, the sheet post-processing device places the second alignment member at a predetermined position and performs the alignment process using the first alignment member for the sheets shifted to one side on the loading tray, and places the first alignment member at a predetermined position and executes a second alignment mode in which the second alignment member performs the alignment operation for the sheets shifted to the other side on the loading tray, or does not execute the alignment process.

2. 2 . The sheet post-processing device according to claim 1 , wherein the control unit executes the second alignment mode or does not execute the alignment process when the Z-folded sheet is discharged onto the stacking tray from the sheet discharge outlet during the sorting process.

3. 3. The sheet post-processing device according to claim 1, wherein when the control unit does not perform the alignment process, the control unit stops the first alignment member at a first position where the sheet discharged to the one side can be aligned, and stops the second alignment member at a second position where the sheet discharged to the other side can be aligned, and then discharges the sheet that has been folded to the one side and the other side on the stacking tray.

4. the first alignment member and the second alignment member are storable in a storage position within the sheet post-processing device body, 3. The sheet post-processing device according to claim 1, wherein the control unit, when not performing the alignment process, discharges the sheet that has been folded to one side and the other side on the stacking tray with the first alignment member and the second alignment member stored in the storage position.

5. The control unit, in the sorting process, separates a portion of the stack of sheets into a plurality of discharge stacks and discharges the separated stacks, When the sheet that has been subjected to the folding process is included in the discharged bundle that is discharged by the first discharge operation among the plurality of discharged bundles, the first alignment member and the second alignment member are stored in the storage position in advance, and the entire discharged bundle is discharged without performing the aligning operation; 5. The sheet post-processing device according to claim 4, wherein, when the sheet that has been subjected to the folded processing is included in the discharged stack discharged by the second or subsequent discharge operation, the alignment operation of the first alignment mode is performed at the timing when the discharge operation of the discharged stack that does not include the sheet that has been subjected to the folded processing is completed, and then the first alignment member and the second alignment member are stored in the storage position, and the remaining discharged stack is discharged without performing the alignment operation.

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