Sheet post-processing device and image forming system with the same

Abstract

To provide a sheet post-processing device capable of improving sheet consistency regardless of a kind of a sheet or an ink amount when forming an image on the sheet, and an image forming system equipped with the same.SOLUTION: A sheet post-processing device includes: a conveying member; a processing tray; a processing part; a discharge port; a discharge tray; a discharge member; a pair of processing tray cursors; a pair of discharge tray cursors; and a control part. The pair of processing tray cursors aligns on the processing tray by sandwiching the sheets in a width direction. The pair of discharge tray cursors aligns on the discharge tray by sandwiching the sheets in the width direction. When performing alignment processing with a front end part of the sheet protruding above the discharge tray, the control part narrows the distance between the pair of discharge tray cursors from an initial distance to a first interval larger than a size in a wide direction of the sheet, and performs a front end alignment processing to align the front end part of the sheet by sandwiching in the width direction. The first interval is adjusted based on output information regarding a characteristic of the sheet.SELECTED DRAWING: Figure 17

Description

Technical Field

[0001] The present invention relates to a sheet post-processing device that performs predetermined post-processing on a sheet after image formation by an image forming apparatus, and an image forming system including the same.

Background Art

[0002] There is known a sheet post-processing device that stacks a plurality of sheets after image formation by an image forming apparatus such as a copying machine or a printer, and performs a stapling process of stapling the stacked sheet bundle together, a punch hole forming process of making punch holes (perforations) with a punch hole forming device, a folding process of forming a crease on the sheet, and the like.

[0003] In such a sheet post-processing device, a processing tray on which a predetermined number of image-formed sheets are loaded is provided. Then, a stapling process, a shift discharge process (sorting process), and the like are performed on the plurality of sheets loaded on the processing tray. In addition, in order to smoothly perform the stapling process and the shift discharge process, etc., the sheets on the processing tray are aligned using an alignment member.

[0004] Patent Document 1 discloses a sheet post-processing device including a pair of alignment members that align the sheets discharged to a stack tray. The pair of alignment members move in the width direction (a direction orthogonal to the sheet conveyance direction) on the stack tray and align the front end portions of the sheets in the width direction.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the configuration of Patent Document 1, the front end portion of the sheet loaded on the processing tray protrudes onto the stack tray. Then, alignment processing of the front end portion of the sheet is performed using a pair of alignment members arranged on the stack tray. However, in Patent Document 1, alignment processing of the rear end portion of the sheet located on the processing tray is not performed. As a result, there is a problem that the alignment of the sheet on the processing tray becomes insufficient.

[0007] In addition, the appropriate interval of the pair of alignment members varies depending on the type of sheet and the ink amount of the sheet on which an image is printed using ink. Therefore, there is a problem that the sheet cannot be properly aligned only by setting the interval of the alignment members according to the sheet size.

[0008] In view of the above problems, an object of the present invention is to provide a sheet post-processing apparatus capable of improving the alignment of a sheet regardless of the type of sheet and the ink amount when forming an image on the sheet, and an image forming system including the same.

Means for Solving the Problems

[0009] To achieve the above object, a first configuration of the present invention is a sheet post-processing apparatus including a conveyance member, a processing tray, a processing unit, a discharge port, a discharge tray, a discharge member, a pair of processing tray cursor sols, a pair of discharge tray cursor sols, and a control unit. The conveyance member conveys a sheet. The processing tray is loaded with a plurality of sheets carried in along a predetermined loading direction by the conveyance member. The processing unit performs predetermined post-processing on the sheets loaded on the processing tray. The discharge port discharges the sheets on the processing tray. The discharge tray is loaded with the sheets discharged from the discharge port. The discharge member conveys the sheets on the processing tray toward the discharge port and discharges them to the discharge tray via the discharge port. The pair of processing tray cursor sols are reciprocally movable in the width direction orthogonal to the sheet conveyance direction on the processing tray, and sandwich and align the sheets in the width direction. The pair of discharge tray cursor sols are reciprocally movable in the width direction on the discharge tray, and sandwich and align the sheets in the width direction. The control unit controls the driving of the processing tray cursor sols and the discharge tray cursor sols. When the control unit performs alignment processing on a sheet in a state where the rear end portion of the sheet is placed on the processing tray and the front end portion protrudes above the discharge tray from the discharge port, the control unit executes front end alignment processing and rear end alignment processing. The front end alignment processing narrows the interval between the pair of discharge tray cursor sols from an initial interval larger than the size of the sheet in the width direction to a first interval narrower than the initial interval and larger than the size of the sheet in the width direction, and sandwiches and aligns the front end portion of the sheet in the width direction. The rear end alignment processing narrows the interval between the pair of processing tray cursor sols from the initial interval to a second interval substantially the same as the size of the sheet in the width direction, and sandwiches and aligns the rear end portion of the sheet in the width direction. The first interval is adjusted based on output information regarding the characteristics of the sheet.

Advantages of the Invention

[0010] According to the first configuration of the present invention, when the front end of the sheet stacked on the processing tray protrudes onto the discharge tray, by performing the front end alignment process and the rear end alignment process, even if the sheet stacked on the processing tray is greatly inclined, the alignment in the width direction of the sheet can be surely performed. Further, by adjusting the first interval between the pair of discharge tray cursor rollers when performing the front end alignment process based on the output information regarding the characteristics of the sheet, the sheet can be stably carried onto the processing tray and aligned without being affected by the ease of skewing of the sheet.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

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Figure 13

Figure 14

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Figure 17

Figure 18

[0012] [1. Configuration of Image Forming System] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of an image forming system including a sheet post-processing apparatus 1 provided with a sheet binding unit 92 according to an embodiment of the present invention, and an image forming apparatus 200 to which the sheet post-processing apparatus 1 is connected.

[0013] As shown in FIG. 1, the image forming apparatus 200 prints an image on a sheet (paper) based on image data input from the outside via a network communication unit (not shown) or image data read by an image reading unit 201 disposed on the upper part of the image forming apparatus 200. In the present embodiment, the image forming apparatus 200 is an inkjet recording apparatus including a recording head (not shown) provided with a large number of nozzle holes for ejecting ink onto a sheet for each color.

[0014] An operation panel 202 is disposed in front of the image reading unit 201. The operation panel 202 is an operation unit for receiving various setting inputs. For example, the user can operate the operation panel 202 to input sheet size information. Further, by operating the operation panel 202, it is also possible to input the number of sheets to be printed and instruct the start of a printing job. The main control unit 203 controls the overall operation of the image forming apparatus 200 and controls each part of the image forming apparatus 200.

[0015] The sheet post-processing device 1 is detachably connected to the side surface of the image forming apparatus 200. The sheet post-processing device 1 performs post-processing such as punch hole formation processing and binding processing on the sheet after image formation (printing) by the image forming apparatus 200. Note that the sheet post-processing device 1 is not limited to performing post-processing on the sheet automatically conveyed from the image forming apparatus 200, and may convey the sheet set in a tray (not shown) by the user to a position where post-processing can be performed and perform post-processing on the sheet.

[0016] [2. Configuration of Sheet Post-Processing Device] FIG. 2 is a side cross-sectional view schematically showing the configuration of the sheet post-processing device 1 of the present embodiment. As shown in FIG. 2, the sheet post-processing device 1 includes a sheet inlet 2, a first sheet conveyance path 3, a first sheet discharge unit 4, a second sheet conveyance path 5, a second sheet discharge unit 6, a third sheet conveyance path 7, a third sheet discharge unit 8, a post-processing unit 9, and a post-processing control unit (control unit) 10.

[0017] The sheet inlet 2 is an opening provided on the side surface of the sheet post-processing device 1 facing the image forming device 200. The sheet conveyed from the image forming device 200 toward the sheet post-processing device 1 passes through the sheet inlet 2 and is carried into the interior of the sheet post-processing device 1.

[0018] The first sheet conveyance path 3 extends in a substantially horizontal direction in a direction away from the image forming device 200 (the left direction in FIG. 2) from the sheet inlet 2 to the first sheet discharge portion 4. The direction from the sheet inlet 2 toward the first sheet discharge portion 4 is referred to as the sheet conveyance direction in the first sheet conveyance path 3. The sheet inlet 2 is located at the upstream end in the sheet conveyance direction of the first sheet conveyance path 3. The first sheet conveyance path 3 has a plurality of conveyance roller pairs 3r and conveys the sheet carried into the sheet post-processing device 1 from the sheet inlet 2 toward the downstream side in the sheet conveyance direction.

[0019] The first sheet discharge portion 4 is provided on the side surface of the sheet post-processing device 1 opposite to the side surface facing the image forming device 200. The first sheet discharge portion 4 is disposed at the downstream end in the sheet conveyance direction of the first sheet conveyance path 3. The first sheet discharge portion 4 includes a first discharge port 41, a first discharge roller pair 42, and a first discharge tray 43.

[0020] The first discharge port 41 is located at the downstream end in the sheet conveyance direction of the first sheet conveyance path 3. The first discharge roller pair 42 is disposed at the first discharge port 41. The first discharge tray 43 is located on the downstream side in the sheet conveyance direction of the first discharge port 41. The sheet conveyed through the first sheet conveyance path 3 and reaching the first discharge port 41 is discharged onto the first discharge tray 43 through the first discharge port 41 by the first discharge roller pair 42. The first discharge tray 43 is one of the final discharge locations for the sheet that has been post-processed by the sheet post-processing device 1.

[0021] The second sheet conveyance path 5 branches from the first branch portion (branch portion) 31 on the first sheet conveyance path 3 and extends horizontally and upward in a direction away from the image forming apparatus 200 (the left direction in FIG. 2) to the second sheet discharge portion 6. The first branch portion 31 is disposed on the downstream side of the punching portion 91 with respect to the sheet conveyance direction in the first sheet conveyance path 3. Note that the direction from the first branch portion 31 toward the second sheet discharge portion 6 is referred to as the sheet conveyance direction in the second sheet conveyance path 5. The first branch portion 31 is located at the upstream end in the sheet conveyance direction of the second sheet conveyance path 5. The second sheet conveyance path 5 has a plurality of conveyance roller pairs 5r, and branches the sheet conveyed on the first sheet conveyance path 3 at the first branch portion 31 and conveys it toward the second sheet discharge portion 6.

[0022] The first branch portion 31 has a first switching guide 311. The first switching guide 311 rotates between a position where it guides the sheet conveyed on the first sheet conveyance path 3 from the sheet inlet 2 side along the first sheet conveyance path 3 to the first discharge port 41 and a position where it branches from the first sheet conveyance path 3 and guides the sheet to the second sheet conveyance path 5. Further, the first switching guide 311 rotates to a position where it guides the sheet that has been subjected to the folding process and passed through the second folding conveyance path 106 described later to the second sheet conveyance path 5. The first switching guide 311 is connected to a drive mechanism (not shown), and its operation is controlled by the post-processing control unit 10.

[0023] The second sheet discharge portion 6 is provided above the first sheet discharge portion 4 on the side surface of the sheet post-processing apparatus 1 opposite to the side surface facing the image forming apparatus 200. The second sheet discharge portion 6 is disposed at the downstream end in the sheet conveyance direction of the second sheet conveyance path 5. The second sheet discharge portion 6 has a second discharge port 61, a second discharge roller pair 62, and a second discharge tray 63.

[0024] The second row outlet 61 is located at the downstream end of the second sheet conveyance path 5 in the sheet conveyance direction. The second discharge roller pair 62 is disposed at the second row outlet 61. The second discharge tray 63 is located on the downstream side of the second row outlet 61 in the sheet conveyance direction. The sheet conveyed through the second sheet conveyance path 5 and reaching the second row outlet 61 is discharged onto the second discharge tray 63 through the second row outlet 61 by the second discharge roller pair 62. The second discharge tray 63 is one of the final discharge locations for the sheets post-processed by the sheet post-processing device 1. Also, sheets that are not post-processed, small-sized sheets, etc. are also discharged onto the second discharge tray 63.

[0025] The third sheet conveyance path 7 branches from the second branch portion 32 on the first sheet conveyance path 3 and extends downward to the third sheet discharge portion 8. The direction from the second branch portion 32 toward the third sheet discharge portion 8 is referred to as the sheet conveyance direction in the third sheet conveyance path 7. The second branch portion 32 is located on the downstream side of the first branch portion 31 with respect to the sheet conveyance direction of the first sheet conveyance path 3 and at the upstream end of the third sheet conveyance path 7 in the sheet conveyance direction. The third sheet conveyance path 7 has a plurality of conveyance roller pairs 7r and conveys the sheet conveyed through the first sheet conveyance path 3 by branching it at the second branch portion 32 toward the third sheet discharge portion 8.

[0026] The second branch portion 32 has a second switching guide 321. The second switching guide 321 rotates between a position that guides the sheet conveyed on the first sheet conveyance path 3 from the sheet inlet 2 side along the first sheet conveyance path 3 to the first row outlet 41 and a position that guides the sheet that has been conveyed on the first sheet conveyance path 3 from the sheet inlet 2 side, passed through the second branch portion 32, and then switched back to the third sheet conveyance path 7. The second switching guide 321 is connected to a drive mechanism (not shown), and its operation is controlled by the post-processing control unit 10.

[0027] The third sheet discharge unit 8 is provided near the lower end of the sheet post-processing apparatus 1 on the side opposite to the side of the sheet post-processing apparatus 1 facing the image forming apparatus 200, below the first sheet discharge unit 4. The third sheet discharge unit 8 includes a third discharge port 81, a third discharge roller pair 82, and a third discharge tray 83.

[0028] The third discharge port 81 is located at the downstream end of the third sheet conveyance path 7 in the sheet conveyance direction. The third discharge roller pair 82 is disposed at the third discharge port 81. The third discharge tray 83 is located on the downstream side of the third discharge port 81 in the sheet conveyance direction. The sheet conveyed through the third sheet conveyance path 7 and reaching the third discharge port 81 is discharged onto the third discharge tray 83 through the third discharge port 81 by the third discharge roller pair 82. The third discharge tray 83 is one of the final discharge locations for the sheets that have been post-processed by the sheet post-processing apparatus 1.

[0029] The post-processing unit 9 performs predetermined post-processing on the sheets that have been image-formed by the image forming apparatus 200 and carried into the sheet post-processing apparatus 1. The post-processing unit 9 includes a punching unit 91, a sheet binding unit 92, a sheet folding unit 100, and a manufacturing unit 94.

[0030] The punching unit 91 is disposed immediately downstream of the sheet inlet 2 in the first sheet conveyance path 3. The punching unit 91 performs a punching process on the sheet conveyed on the first sheet conveyance path 3 to form punch holes.

[0031] The sheet binding unit 92 is disposed immediately upstream of the first sheet discharge unit 4 with respect to the sheet conveyance direction of the first sheet conveyance path 3. The sheet binding unit 92 performs a stapling process (binding process) on a sheet bundle formed by stacking a plurality of sheets to bind the sheet bundle. The detailed configuration of the sheet binding unit 92 will be described later.

[0032] The sheet folding unit 100 is disposed on the downstream side of the punching portion 91 and on the upstream side of the sheet binding unit 92 with respect to the sheet conveyance direction of the first sheet conveyance path 3. The sheet folding unit 100 performs a folding process on a single sheet to form a fold line. The sheet folding unit 100 can perform a folding process such as double folding, Z-folding, outside triple folding, inside triple folding, etc. on a single sheet.

[0033] The manufacturing unit 94 is disposed immediately upstream of the third sheet discharge unit 8 with respect to the sheet conveyance direction of the third sheet conveyance path 7. The manufacturing unit 94 includes a middle folding portion 941 and a middle binding portion 942. The manufacturing unit 94 performs a middle folding process and a middle binding process of folding and binding a substantially central portion in the sheet conveyance direction on a sheet bundle formed by stacking a plurality of sheets to form a booklet.

[0034] The post-processing control unit (control unit) 10 includes a CPU, a storage unit, and other electronic circuits and electronic components (all not shown). The post-processing control unit 10 is communicably connected to the main body control unit 203 (see FIG. 1) of the image forming apparatus 200. The post-processing control unit 10 receives a command from the main body control unit 203 and controls the operations of the respective components provided in the sheet post-processing apparatus 1 based on the programs and data for control stored in the storage unit using the CPU, and performs processes related to the functions of the sheet post-processing apparatus 1. Each of the first sheet conveyance path 3, the first sheet discharge unit 4, the second sheet conveyance path 5, the second sheet discharge unit 6, the third sheet conveyance path 7, the third sheet discharge unit 8, and the post-processing unit 9 receives an individual command from the post-processing control unit 10 and performs post-processing on the sheet in conjunction. Note that the function of the post-processing control unit 10 may be shared by the main body control unit 203 of the image forming apparatus 200.

[0035] [3. Configuration of Sheet Binding Unit] Next, the configuration of the sheet binding unit 92 will be described. FIG. 3 is a perspective view of the sheet binding unit 92 mounted on the sheet post-processing apparatus 1. FIG. 4 is a side view of the sheet binding unit 92.

[0036] As shown in FIG. 3, the sheet stapling unit 92 includes a processing tray 521, a staple unit 71, and a reference plate 73.

[0037] The processing tray 521 is a rectangular tray extending in the sheet width direction (arrow AA' direction) and the loading direction. A plurality of sheets S (sheet bundles) to be stapled are loaded on the processing tray 521. At this time, the sheets S are loaded onto the processing tray 521 along the alignment direction (opposite to the loading direction) toward the lower right direction (arrow B direction) in FIG. 4. The stapled sheet bundle is finally sent out by the first discharge roller pair 42 (see FIG. 2) in the direction opposite to the above alignment direction (upper left direction in FIG. 4) and discharged to the first discharge tray 43 (see FIG. 2). On the downstream side in the loading direction of the processing tray 521 (lower left side in FIG. 3), a discharge lower roller 421 constituting the first discharge roller pair 42 is supported.

[0038] The processing tray 521 includes a tray central portion 522 and a processing tray cursor 523. The tray central portion 522 is arranged at the central portion in the sheet width direction (arrow AA' direction, hereinafter simply referred to as the width direction) on the upper surface portion of the processing tray 521. The tray central portion 522 is a thin plate-like member fixed on the processing tray 521 with a slight height.

[0039] A pair of processing tray cursors 523 are arranged so as to sandwich the tray central portion 522 in the width direction. The processing tray cursor 523 regulates the position of the sheet S in the width direction that is loaded onto the processing tray 521. The processing tray cursor 523 is also made of a thin plate-like member like the tray central portion 522, and has side walls erected upward at the end portions in the width direction. A guide groove 524 extending along the width direction is formed in the processing tray 521. The processing tray cursor 523 is reciprocally movable in the width direction along the guide groove 524 via a drive mechanism (not shown) such as a rack and a pinion gear. In the present embodiment, every time a sheet is loaded onto the processing tray 521, the processing tray cursor 523 is reciprocally moved by the drive mechanism. As a result, the sheets loaded on the processing tray 521 are aligned in the width direction.

[0040] The staple portion 71 is disposed to face the edge on the leading end side in the alignment direction of the sheet (the right side in FIG. 4). The staple portion 71 is movable in the sheet width direction orthogonal to the carrying direction along the edge of the sheet by the driving force of the staple portion driving motor M1, and staples the bundle of sheets.

[0041] As shown in FIG. 4, the staple portion 71 includes a staple main body portion 711 and a staple movable portion 712. The staple main body portion 711 is the main body portion of the staple portion 71 and houses a plurality of staple pins (not shown) therein. The staple movable portion 712 is movable up and down and drives the staple pins into the sheet. A recess 713 into which the edge of the sheet enters is formed between the staple main body portion 711 and the staple movable portion 712.

[0042] The reference plate 73 is fixed at three positions spaced apart in the width direction so as to face the end portion on the downstream side in the alignment direction of the processing tray 521 (the upper right side in FIG. 3, the lower right side in FIG. 4). The reference plate 73 has a substantially U-shaped cross section with the upstream side in the alignment direction (the upper left side in FIG. 4) open when viewed in a cross section orthogonal to the sheet width direction. The reference plate 73 abuts against the edge of the sheet carried into the processing tray 521 and aligns the sheet in the carrying direction.

[0043] [4. Configuration around the processing tray of the sheet binding unit] FIG. 5 is a side cross-sectional view showing the structure around the processing tray 521 and the alignment member 55. As shown in FIG. 5, a pair of carry-in rollers 54 is disposed above the processing tray 521. The pair of carry-in rollers 54 is composed of a carry-in upper roller 54a and a carry-in lower roller 54b.

[0044] A sheet detection sensor 93 is disposed near the pair of carry-in rollers 54. The sheet detection sensor 93 detects the timing when the sheet S passes through the pair of carry-in rollers 54. As the sheet detection sensor 93, for example, a PI (photo interrupter) sensor having a detection unit composed of a light emitting unit and a light receiving unit is used.

[0045] On the downstream side (the left side in FIG. 5) of the carrying roller pair 54 with respect to the carrying direction of the sheet S, a tapping member 53 and an aligning member 55 are provided. The tapping member 53 is supported so as to be swingable along the carrying direction of the sheet S. The tapping member 53 swings downward at the timing when the rear end of the sheet S passes through the carrying roller pair 54, thereby tapping the sheet S downward and guiding it along the processing tray 521.

[0046] The aligning members 55 are arranged at a plurality of positions (four positions in this embodiment) along the width direction (the direction perpendicular to the plane of FIG. 5). The aligning members 55 move (switch back) the sheet S carried onto the processing tray 521 in the aligning direction approaching the reference plate 73 to assist in aligning the sheet S. The aligning members 55 include paddle holders 56 and aligning paddles 57.

[0047] The paddle holder 56 is supported above the processing tray 521 so as to be swingable along the carrying direction of the sheet S. A rotational driving force is input to the swing shaft 56a of the paddle holder 56 by a holder driving motor M2. As the holder driving motor M2, a stepping motor capable of accurately controlling the rotational direction and the amount of rotation (rotation angle) by pulse control is used. Further, an HP detection sensor (not shown) for detecting the reference position (home position) of the paddle holder 56 (aligning paddle 57) is provided. The post-processing control unit 10 estimates the height (distance from the processing tray 521) of the aligning paddle 57 based on the detection signal of the HP detection sensor and the number of sheets S stacked on the processing tray 521.

[0048] FIG. 6 is a perspective view of the aligning paddle 57. The aligning paddle 57 has a paddle body 571 and a paddle portion 572. The paddle body 571 is cylindrical, and a fulcrum portion 571a is formed. The fulcrum portion 571a is a through hole passing through the central axis of the paddle body 571 and is rotatably supported at the swing end (the left end in FIG. 5) of the paddle holder 56. The paddle portion 572 is a rubber sheet and protrudes in the tangential direction (upstream side in the rotation direction) from a position that is point-symmetrical to the outer peripheral surface of the paddle body 571 around the fulcrum portion 571a.

[0049] The alignment paddle 57 is input with a rotational driving force in the direction of sending out the sheet S in the alignment direction (counterclockwise direction in FIG. 5) by a driving source (not shown) such as a motor. By rotating while the paddle portion 572 of the alignment paddle 57 contacts the upper surface of the sheet S carried into the processing tray 521, the sheet S is moved in the alignment direction, and the edge of the sheet S is abutted against the reference plate 73 for alignment. The alignment paddle 57 stops after rotating by a preset number of rotations (for example, two rotations).

[0050] The swinging of the paddle holder 56 is controlled based on the detection timing of the sheet detection sensor 93. Specifically, the paddle holder 56 is swung upward at the timing when the sheet detection sensor 93 detects that the leading end of the sheet S has passed through the carry-in roller pair 54. As a result, the paddle portion 572 is separated from the upper surface of the processing tray 521 (or the sheet S loaded on the processing tray 521).

[0051] A support member 58 is disposed below the processing tray 521. The support member 58 is a rod-shaped member having a predetermined width in the width direction and extending in an arc shape in the discharge direction, and is disposed below the first discharge port 41. More specifically, the support member 58 is disposed below the processing tray 521 and below the discharge path of the sheet S discharged from the first discharge roller pair 42 along the processing tray 521. In the present embodiment, the support members 58 are disposed at two positions in the sheet width direction with a predetermined interval from the central portion of the processing tray 521 in the sheet width direction.

[0052] The support member 58 is movable between a protruding position (solid line position in FIG. 5) protruding to the downstream side in the discharge direction (left side in FIG. 5) from the first discharge roller pair 42 and a retracted position (broken line position in FIG. 5) retracted to the upstream side in the discharge direction (right side in FIG. 5) from the first discharge roller pair 42. The support member 58 is disposed at the protruding position when the sheet S is carried into the processing tray 521 (during switchback) and supports a part of the sheet S protruding onto the first discharge tray 43.

[0053] FIG. 5 shows the state immediately before the sheet S is carried onto the processing tray 521. The paddle holder 56 swings upward (clockwise), and the alignment paddle 57 is disposed at a position (reference position) separated from the processing tray 521. Also, the nip between the lower discharge roller 421 and the upper discharge roller 422 constituting the first discharge roller pair 42 is released. As a result, the sheet S carried onto the processing tray 521 from the carry-in roller pair 54 once passes through the first discharge roller pair 42 and protrudes onto the first discharge tray 43. The front end Sf of the sheet S protruding onto the first discharge tray 43 is supported by a support member 58 disposed at the protruding position.

[0054] FIG. 7 is a diagram showing the state where the sheet S is carried onto the processing tray 521. At the timing when the rear end of the sheet S carried onto the processing tray 521 passes through the carry-in roller pair 54, the paddle holder 56 is swung in the reverse direction (counterclockwise). As a result, as shown in FIG. 7, the alignment paddle 57 is disposed at a position (operating position) where the paddle portion 572 contacts the upper surface of the sheet S. By repeating the above operation every time the sheet S is carried in, it is possible to reliably bring the paddle portion 572 into contact with the upper surface of the sheet S while avoiding interference between the leading end of the sheet S carried onto the processing tray 521 and the paddle portion 572.

[0055] [5. Alignment of the Sheet on the First Discharge Tray] Next, the alignment operation of the sheet S on the first discharge tray 43 will be described. FIG. 8 is a perspective view of the first discharge tray 43 of the sheet post-processing apparatus 1 of the present embodiment and its periphery. FIG. 9 is a perspective view of the discharge tray cursor 80 and its periphery. FIG. 10 is a side cross-sectional view showing the vertical position of the discharge tray cursor 80 when aligning the sheet S discharged onto the first discharge tray 43.

[0056] As shown in FIGS. 8 to 10, the sheet post-processing apparatus 1 includes a pair of discharge tray sorters 80. The pair of discharge tray sorters 80 align the sheet S in the width direction (the direction of arrow AA′) on the first discharge tray 43. For this reason, the pair of discharge tray sorters 80 are configured to be reciprocally movable in the width direction on the first discharge tray 43 independently of each other. The pair of discharge tray sorters 80 move in the width direction by separate width-direction drive mechanisms.

[0057] Hereinafter, the configuration of the width-direction drive mechanism will be described. Note that the configurations of the width-direction drive mechanisms of the pair of discharge tray sorters 80 are the same. Therefore, hereinafter, the configuration will be described by focusing on the width-direction drive mechanism corresponding to one of the discharge tray sorters 80. The description of the configuration of the width-direction drive mechanism corresponding to the other discharge tray sorter 80 will be omitted by referring to the following description.

[0058] The width-direction drive mechanism includes a carriage 81. The discharge tray sorter 80 is supported by the carriage 81. The carriage 81 is supported by a guide shaft 82. The guide shaft 82 is disposed above the first discharge port 41 and extends in the width direction (the direction of arrow AA′). The carriage 81 moves in the width direction along the guide shaft 82. That is, the guide shaft 82 guides the movement of the carriage 81 in the width direction.

[0059] Although not shown, the width-direction drive mechanism includes, for example, a width position adjustment motor, a plurality of pulleys including a drive pulley that rotates by the driving force of the width position adjustment motor, and an endless belt wound around the plurality of pulleys. The carriage 81 is connected to the belt of the width-direction drive mechanism. In this configuration, when the width position adjustment motor is driven, the discharge tray sorter 80 moves in the width direction together with the carriage 81. The post-processing control unit 10 controls the width position adjustment motor.

[0060] Further, a pair of discharge tracer soles 80 are each configured to be rotatable so as to swing the end portion on the side opposite to the side supported by the carriage 81 in the vertical direction. In other words, the pair of discharge tracer soles 80 are each movable in the vertical direction. The pair of discharge tracer soles 80 are rotated by a vertical drive mechanism.

[0061] The vertical drive mechanism includes a vertical position adjustment motor M3 that rotates a drive shaft 83. The drive shaft 83 extends in the width direction. The drive shaft 83 is inserted into the pair of carriages 81. However, even when the drive shaft 83 rotates, the pair of carriages 81 do not rotate. The pair of carriages 81 are movable in the width direction along the drive shaft 83.

[0062] The vertical position adjustment motor M3 is connected to one end of the drive shaft 83 via a drive transmission member such as a gear. Further, the drive shaft 83 is connected to each rotation shaft 80a (see FIG. 10) of the pair of discharge tracer soles 80 via a drive transmission member such as a gear. Thereby, when the vertical position adjustment motor M3 is driven, the pair of discharge tracer soles 80 rotate. In other words, when the vertical position adjustment motor M3 is driven, the pair of discharge tracer soles 80 move in the vertical direction. The post-processing control unit 10 controls the vertical position adjustment motor M3.

[0063] Further, the first discharge tray 43 has a recess 431 on the upper surface on which the sheet S is loaded. When aligning the sheet S discharged onto the first discharge tray 43, alignment is performed by the pair of discharge tracer soles 80 with a part of the pair of discharge tracer soles 80 inserted into the recess 431 as shown in FIG. 10. In other words, when the post-processing control unit 10 aligns the sheet S on the first discharge tray 43, the pair of discharge tracer soles 80 are arranged at a first position facing the side surface of the sheet S loaded on the first discharge tray 43. The vertical position of the pair of discharge tracer soles 80 shown in FIG. 10 is the first position.

[0064] [6. Rear end alignment process and front end alignment process of sheet] When the sheet S is loaded on the processing tray 521, the post-processing control unit 10 performs a rear-end alignment process of sandwiching the rear end portion Sr of the sheet S located on the processing tray 521 in the width direction with a pair of processing tray cursor 523. By performing the rear-end alignment process, the post-processing control unit 10 aligns the sheet S on the processing tray 521 in the width direction.

[0065] Here, the sizes of the sheets S on which post-processing is performed by the sheet post-processing apparatus 1 are various. For this reason, depending on the size of the sheet S, as shown in FIG. 11, even when the sheet S is drawn into the processing tray 521 and the rear end portion Sr of the sheet S is brought into contact with the reference plate 37, the front end portion Sf of the sheet S protrudes onto the first discharge tray 43 from the first discharge port 41.

[0066] If the sheet S with the front end portion Sf protruding onto the first discharge tray 43 is greatly inclined, there may occur a disadvantage that it becomes difficult to align the sheet S in the width direction only by the rear-end alignment process. For example, since the sheet S is wet with ink, the frictional resistance between the sheets S overlapping vertically may increase. In this case, it becomes difficult to align the sheets S.

[0067] Therefore, when performing the alignment process on the sheet S loaded on the processing tray 521 in a state where the front end portion Sf protrudes above the first discharge tray 43 from the first discharge port 41, the post-processing control unit 10 performs a front-end alignment process in addition to the rear-end alignment process. As the front-end alignment process, the post-processing control unit 10 performs a process of sandwiching the front end portion Sf of the sheet S protruding onto the first discharge tray 43 in the width direction with a pair of discharge tray cursor 80.

[0068] In the present embodiment, as described above, when the sheet S is loaded on the processing tray 521, in addition to the rear-end alignment process of sandwiching the rear end portion Sr of the sheet S in the width direction with a pair of processing tray cursor 523, a front-end alignment process of sandwiching the front end portion Sf of the sheet S in the width direction with a pair of discharge tray cursor 80 is performed. Thereby, even when the sheet S loaded on the processing tray 521 is greatly inclined in the case where the front end portion Sf of the sheet S loaded on the processing tray 521 protrudes onto the first discharge tray 43, the alignment of the sheet S in the width direction can be surely performed.

[0069] Hereinafter, with reference to FIGS. 12 to 14, the flow of the alignment process performed on the sheet S loaded on the processing tray 521 will be described. FIGS. 12 to 14 are schematic views of the sheet S loaded on the processing tray 521 as viewed from above. In FIGS. 12 to 14, the direction from the right to the left in the figure corresponds to the sheet conveyance direction. Also, the vertical direction in the figure corresponds to the width direction (the direction of arrow AA'). The same applies to FIGS. 15 and 16 described later.

[0070] Note that in FIGS. 12 and 13, for the sake of easily understanding the behavior of the sheet S when the front-end alignment process and the rear-end alignment process are performed, the sheet S on the processing tray 521 is illustrated by being inclined greatly for convenience.

[0071] First, as shown in FIG. 12, when loading the sheet S on the processing tray 521, the post-processing control unit 10 holds the interval in the width direction between the pair of discharge tray cursor 80 at the initial interval W0. Similarly, the post-processing control unit 10 holds the interval in the width direction between the pair of processing tray cursor 523 at the initial interval W0.

[0072] The initial interval W0 is an interval larger than the size in the width direction of the sheet S to be loaded on the processing tray 521 this time. The initial interval W0 changes according to the size in the width direction of the sheet S. The larger the size in the width direction of the sheet S, the larger the initial interval W0.

[0073] Also, the initial interval W0 may be the same or different between the pair of discharge tray cursor 80 and the pair of processing tray cursor 523. The initial interval W0 of the pair of discharge tray cursor 80 only needs to be larger than the first interval W1 described later. The initial interval W0 of the pair of processing tray cursor 523 only needs to be larger than the second interval W2 described later.

[0074] For example, when loading the sheet S on the processing tray 521 and aligning the sheet S on the processing tray 521, the post-processing control unit 10 arranges the vertical positions of the pair of discharge tray cursor rollers 80 at the second position (the position for front-end alignment processing). The vertical positions of the pair of discharge tray cursor rollers 80 shown in FIG. 11 are at the second position. The second position is a position above the first position when aligning the sheet S discharged to the first discharge tray 43, and is a position facing the side surface of the front end Sf of the sheet S protruding on the first discharge tray 43 (a position where it can contact the front end Sf of the sheet S from the width direction).

[0075] The post-processing control unit 10 holds the interval between the pair of discharge tray cursor rollers 80 at the initial interval W0, holds the interval between the pair of processing tray cursor rollers 523 at the initial interval W0, and while holding the vertical positions of the pair of discharge tray cursor rollers 80 at the second position, draws in and loads the sheet S onto the processing tray 521.

[0076] When the sheet S is loaded on the processing tray 521, as shown in FIG. 13, the post-processing control unit 10 performs front-end alignment processing. Specifically, the post-processing control unit 10 narrows the interval in the width direction between the pair of discharge tray cursor rollers 80 to a first interval W1 smaller than the initial interval W0. In other words, the post-processing control unit 10 sandwiches the front end Sf of the sheet S with the pair of discharge tray cursor rollers 80 and aligns it in the width direction.

[0077] The first interval W1 is equal to or greater than the size of the sheet S in the width direction and smaller than the initial interval W0. For example, the first interval W1 is a predetermined amount larger than the size of the sheet S in the width direction. In other words, the first interval W1 is slightly larger than the size of the sheet S in the width direction. The first interval W1 varies depending on the size of the sheet S in the width direction. The larger the size of the sheet S in the width direction, the larger the first interval W1.

[0078] After the execution of the front-end integration process, as shown in FIG. 14, the post-processing control unit 10 performs a back-end integration process. Specifically, the post-processing control unit 10 narrows the interval in the width direction between the pair of processing tracer soles 523 to a second interval W2 that is smaller than the initial interval W0. In other words, the post-processing control unit 10 sandwiches the rear end portion Sr of the sheet S with the pair of processing tracer soles 523 and aligns them in the width direction.

[0079] The second interval W2 is the same as (including substantially the same as) the size of the sheet S in the width direction and is smaller than the first interval W1. That is, the interval in the width direction (the first interval W1) between the pair of discharge tracer soles 80 during the front-end integration process is larger than the interval in the width direction (the second interval W2) between the pair of processing tracer soles 523 during the back-end integration process. The second interval W2 changes according to the size of the sheet S in the width direction. The larger the size of the sheet S in the width direction, the larger the second interval W2.

[0080] In the present embodiment, as described above, the first interval W1 and the second interval W2 are different. And the post-processing control unit 10 makes the execution timings of the front-end integration process and the back-end integration process different from each other. Specifically, the post-processing control unit 10 performs the back-end integration process after performing the front-end integration process.

[0081] In the back-end integration process, the interval between the pair of processing tracer soles 523 is the same as the size of the sheet S in the width direction. On the other hand, in the front-end integration process, the interval between the pair of discharge tracer soles 80 is slightly larger than the size of the sheet S in the width direction. Therefore, by performing the front-end integration process after the front-end integration process, the inclination of the sheet S can be roughly corrected before accurately aligning the sheet S (before the back-end integration process).

[0082] Here, each time one sheet S is loaded on the processing tray 521, the post-processing control unit 10 performs the front-end integration process and the back-end control process. Thereby, the sheets S on the processing tray 521 can be reliably aligned one by one.

[0083] After performing the front-end integration process and the back-end integration process on one sheet S, when performing the front-end integration process and the back-end integration process on the second and subsequent sheets S, when loading the second and subsequent sheets S onto the processing tray 521, the post-processing control unit 10 returns the interval between the pair of discharge tray cursor 80 and the pair of processing tray cursor 523 to the initial interval W0. And in that state, a new sheet S is drawn into and loaded onto the processing tray 521, and the front-end integration process and the back-end integration process are performed. That is, when sequentially drawing in and loading a plurality of sheets S onto the processing tray 521, the post-processing control unit 10 repeats the series of processes shown in FIGS. 12 to 14.

[0084] When discharging the sheet S from the processing tray 521 to the first discharge tray 43, the post-processing control unit 10 holds the vertical position of the pair of discharge tray cursor 80 at the first position or the second position. For this reason, when discharging the sheet S from the processing tray 521 to the first discharge tray 43 while maintaining the interval in the width direction of the pair of discharge tray cursor 80 at the first interval W1, the sheet S may come into contact with the pair of discharge tray cursor 80 and the discharge of the sheet S may be inhibited.

[0085] For this reason, when discharging the sheet S from the processing tray 521 to the first discharge tray 43, as shown in FIG. 15, the post-processing control unit 10 holds the interval in the width direction of the pair of discharge tray cursor 80 at a third interval W3 that is larger than the first interval W1. That is, the post-processing control unit 10 widens the interval in the width direction of the pair of discharge tray cursor 80 compared to the front-end integration process. The post-processing control unit 10 discharges the sheet S from the processing tray 521 to the first discharge tray 43 while holding the interval between the pair of discharge tray cursor 80 at the third interval W3. Thereby, it is possible to suppress the sheet S from coming into contact with the pair of discharge tray cursor 80 and inhibiting the discharge of the sheet S. The third interval W3 may be the same as the initial interval W0, or may be larger than the initial interval W0.

[0086] Note that the sheet post-processing device 1 has a sorting discharge (shift discharge) function. In sorting discharge, for example, the discharge position on the first discharge tray 43 is shifted in the width direction in units of bundles (parts) of the sheet S. That is, in sorting discharge, the sheet S on the processing tray 521 is shifted in the width direction and then discharged to the first discharge tray 43.

[0087] When discharging the sheet S on the processing tray 521 to the first discharge tray 43 after shifting it in the width direction, as shown in FIG. 16, the post-processing control unit 10 moves the pair of processing tray cursors 523 in the shift direction of the sheet S, and in conjunction with the movement of the pair of processing tray cursors 523 in the shift direction, moves the pair of discharge tray cursors 80 in the shift direction. Thereby, in sorting discharge, it is possible to suppress the sheet S from contacting the pair of discharge tray cursors 80 and inhibiting the discharge of the sheet S.

[0088] Depending on the size of the sheet S, when the sheet S is loaded on the processing tray 521, the amount of protrusion of the sheet S loaded on the processing tray 521 from the first discharge port 41 is small. Therefore, as a modification, when the amount of protrusion of the sheet S loaded on the processing tray 521 from the first discharge port 41 is small, it may not be necessary to perform the front-end alignment process when the sheet S is loaded on the processing tray 521.

[0089] [7. Adjustment of the distance between the discharge tray cursors in the front-end alignment process] By the way, the degree of skew of the sheet S when performing the front-end alignment process on the sheet S protruding on the first discharge tray 43 varies greatly depending on the type of the sheet S (size, thickness, basis weight, grain direction, surface smoothness). Specifically, when the size of the sheet S in the width direction is larger than the size in the conveyance direction, the degree of skew of the sheet S tends to increase. Also, when the surface smoothness of the sheet S is high (friction is small), the moving load of the sheet S is small, so the degree of skew of the sheet S tends to increase.

[0090] Further, when the image forming apparatus 200 connected to the sheet post-processing apparatus 1 is an inkjet recording apparatus, the degree of skew of the sheet S varies depending on the amount of ink used for image recording and the image pattern formed by the ink. For example, when there is a bias in the width direction in the image pattern formed by the ink, the degree of skew of the sheet S tends to increase. Therefore, it may be difficult to stably convey and align the sheet S only by setting the interval of the discharge tray cursor 80 according to the width direction size of the sheet S.

[0091] Therefore, in the present embodiment, based on the output information regarding the characteristics of the sheet S, the first interval W1 of the discharge tray cursor 80 during the front-end alignment process is adjusted. Specifically, information regarding the output information regarding the characteristics of the sheet S (type of the sheet S and ink amount) is input from the image forming apparatus 200. The post-processing control unit 10 adjusts the first interval W1 of the discharge tray cursor 80 according to the input output information regarding the characteristics of the sheet S.

[0092] According to the above configuration, the first interval W1 of the discharge tray cursor 80 determined according to the size of the sheet S carried onto the processing tray 521 is appropriately corrected based on the output information regarding the characteristics of the sheet S. As a result, the sheet S can be stably carried onto and aligned on the processing tray 521 without being affected by the type of the sheet S or the ink amount. Therefore, it is possible to suppress the deterioration of alignment in the front-end alignment process due to the first interval W1 of the discharge tray cursor 80 being too wide, and the occurrence of stacking defects due to the first interval W1 being too narrow and the sheet S colliding with the discharge tray cursor 80.

[0093] FIG. 17 is a flowchart showing an example of binding process control executed in the sheet post-processing apparatus 1 of the present embodiment. FIG. 18 is a flowchart showing an example of adjustment control of the first interval W1 of the discharge tray cursor 80 in FIG. 17. With reference to FIGS. 1 to 16 as necessary, the adjustment procedure of the first interval W1 of the discharge tray cursor 80 will be described along the steps of FIGS. 17 and 18. In the initial state, it is assumed that the first interval W1 and the second interval W2 of the discharge tray cursor 80 are set to reference intervals corresponding to the sheet size (for example, A4 size) with the highest usage frequency. In the following description, the output information regarding the characteristics of the sheet S is also simply referred to as the output information of the sheet.

[0094] When a binding process command for the sheet S is input from the main body control unit 203 (see FIG. 1) of the image forming apparatus 200, the output information of the sheet S is input together with the binding process command (step S1). Among the output information of the sheet S, information regarding the type of the sheet S such as the size, thickness, basis weight, grain direction, and surface smoothness of the sheet S is input from the operation panel 202 of the image forming apparatus 200. For example, the manufacturer, product name, product number, etc. of the sheet S may be stored in advance in the main body control unit 203 in association with the information regarding the corresponding type of the sheet S. Thereby, the main body control unit 203 can recognize the information regarding the type of the sheet S to be used only by the user selecting the manufacturer, product name, product number, etc. of the sheet S from the operation panel 202.

[0095] The information regarding the ink amount is calculated by the main body control unit 203 based on the ink amount used for image recording based on the image data transmitted from a host device such as a personal computer or the image reading unit 201, and is transmitted from the main body control unit 203.

[0096] The post-processing control unit 10 (see FIG. 2) determines whether it is necessary to adjust the interval of the discharge tray cursor 80 when performing the front-end alignment process based on the input output information of the sheet S (step S2). If it is determined that the adjustment of the working position is necessary (Yes in step S2), the post-processing control unit 10 adjusts the first interval W1 and the second interval W2 of the discharge tray cursor 80 from the reference intervals (step S3).

[0097] Specifically, as shown in FIG. 18, first, the first interval W1 and the second interval W2 are set based on the width direction size of the sheet S included in the output information of the sheet S (step S31). The adjustment amount from the reference action position is determined based on a correction table that defines the relationship between the width direction size of the sheet S and the corresponding first interval W1 and second interval W2.

[0098] Next, the post-processing control unit 10 determines whether the printing rate Pr of the sheet S exceeds the reference printing rate Pr1 (step S32). When the printing rate Pr exceeds the reference printing rate Pr1 (Yes in step S32), the post-processing control unit 10 determines whether the type of the sheet S is likely to skew (step S33).

[0099] When the amount of ink used for image recording increases, the sheet S tends to skew more easily. Also, when the size in the width direction is larger than the size in the conveyance direction or in the case of an image pattern with a bias in the width direction, and when the surface smoothness of the sheet S is large, the sheet S tends to skew more easily.

[0100] Therefore, when the printing rate Pr exceeds the reference printing rate Pr1 and the type of the sheet S has a large degree of skew (Yes in step S33), the value obtained by adding the correction value α to the set value of the first interval W1 set in step S31 is used as the first interval W1 (step S34). That is, correction is performed in the direction in which the interval of the discharge tray cursor 80 becomes wider than the set first interval W1.

[0101] On the other hand, when the printing rate Pr is less than or equal to the reference printing rate Pr1 (No in step S32), or when the printing rate Pr exceeds the reference printing rate Pr1 but the type of the sheet S has a small degree of skew (No in step S33), the set value set in step S31 is used as the first interval W1 (step S35).

[0102] When it is determined that the adjustment of the interval of the discharge tray cursor 80 is not necessary (No in step S2), the post-processing control unit 10 proceeds to the next step without changing the first interval W1 and the second interval W2 from the reference interval.

[0103] Next, the post-processing control unit 10 starts to carry the sheet S carried into the sheet post-processing apparatus 1 through the sheet carry-in port 2 to the processing tray 521 (step S4). Specifically, when the sheet detection sensor 93 detects that the rear end of the sheet S has passed through the carry-in roller pair 54, the post-processing control unit 10 taps the rear end of the sheet S with the tapping member 53 to align it along the processing tray 521, and then the alignment paddle 57 moves to the operating position and the paddle portion 572 contacts the upper surface of the sheet S.

[0104] In this state, by rotating the alignment paddle 57, the sheet S is drawn along the processing tray 521 in the alignment direction (arrow B direction). Also, the front-end alignment process by the discharge tray cursor 80 (see FIG. 8) and the rear-end alignment process by the processing tray cursor 523 (see FIG. 3) are performed simultaneously. Thereafter, the sheet S is further sent downstream in the alignment direction by the alignment paddle 57 and aligned and stacked in the carry-in direction by the reference plate 73.

[0105] The post-processing control unit 10 counts the number of sheets S carried into the processing tray 521 (step S5). And each time one sheet S is carried in, the front-end alignment process and the rear-end alignment process are performed.

[0106] Next, the post-processing control unit 10 determines whether a predetermined number of sheets S have been carried into the processing tray 521 (step S6). If the predetermined number of sheets S have not been carried in (No in step S6), it returns to step S4 and continues to carry the sheet S into the processing tray 521 and count the number of sheets carried in.

[0107] When a predetermined number of sheets S are carried in (Yes in step S6), the post-processing control unit 10 transmits a control signal to the stapler unit drive motor M1 (see FIG. 3) to move the stapler unit 71 to a predetermined stapling position. After the stapler unit 71 has moved to the predetermined stapling position, the post-processing control unit 10 transmits a control signal to the stapler unit 71 to perform stapling on the plurality of sheets S aligned by the reference plate 73 (step S7).

[0108] Next, the post-processing control unit 10 causes the first discharge roller pair 42 to come into contact (nip formation) and rotates the first discharge roller pair 42 in the discharge direction. Thereby, the bundle of sheets S subjected to stapling is discharged to the first discharge tray 43 (both see FIG. 2) by the first discharge roller pair 42 (step S8). After the post-processing control unit 10 has discharged the bundle of sheets S, it transmits a control signal to the stapler unit drive motor M1 to move the stapler unit 71 to the standby position (step S9).

[0109] Thereafter, the post-processing control unit 10 determines whether or not the binding process has ended (step S10). If the binding process is continuing (No in step S10), the process returns to step S4, and the carrying-in of the sheets S to the processing tray 521, the counting of the number of carried-in sheets, the execution of the stapling process, the discharge of the sheet bundle, and the movement of the stapler unit 71 to the standby position are repeated (steps S4 to S10). If the binding process has ended (Yes in step S10), the process is terminated as it is.

[0110] According to the control examples shown in FIGS. 17 and 18, based on the size of the sheet S in the width direction, the first interval W1 and the second interval W2 of the discharge tray cursor 80 during the front-end alignment process are set. Therefore, regardless of the size of the sheet S in the width direction, the sheet S can be stably conveyed and aligned.

[0111] Further, the first interval W1 is corrected to an optimal interval based on the type of the sheet S (degree of skew) and the printing rate. Therefore, the sheet S can be stably conveyed and aligned without being affected by the type of the sheet S or the amount of ink when an image is recorded by the inkjet recording apparatus.

[0112] As described above, the embodiments of the present invention have been described. However, the scope of the present invention is not limited thereto, and various modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the post-processing control unit 10 automatically adjusts the operating position of the alignment paddle 57 based on the output information of the sheet S. However, the user may be able to adjust the interval of the discharge tray cursor 80 at an arbitrary timing. For example, an adjustment mode for switching the interval of the discharge tray cursor 80 in multiple steps may be provided on the operation panel 202, and the user may be able to select the mode according to the status (alignment) of the stapling process in the sheet binding unit 92.

[0113] In the above embodiment, an example in which the sheet binding unit 92 performs a binding process on the sheet S stacked on the processing tray 521 has been shown. However, the present invention is not limited thereto, and a configuration in which a shift discharge process or a folding process is performed on the sheet S stacked on the processing tray 521 may be employed.

[0114] In the above embodiment, information regarding the type of the sheet S among the output information of the sheet S is input from the operation panel 202 of the image forming apparatus 200. However, the output information of the sheet S may be automatically acquired. For example, a media sensor is arranged at an arbitrary position on the sheet conveyance path from the image forming apparatus 200 to the sheet post-processing apparatus 1, and the media sensor can detect the output information of the sheet S, such as the size, thickness, basis weight, grain direction, surface smoothness, and ink amount of the sheet S carried from the image forming apparatus 200 to the sheet post-processing apparatus 1.

[0115] For example, when detecting the thickness of the sheet S, as a media sensor, a laser coaxial displacement meter that detects the thickness by sandwiching the sheet S with two optical sensors can be used.

[0116] When detecting the basis weight of the sheet S, as a media sensor, a basis weight sensor that measures the basis weight based on the light transmittance of the sheet S can be used. Since the relationship between the light transmittance and the basis weight varies depending on the type of the sheet S, it is necessary to select an optimal basis weight conversion formula for each type of the sheet S. Also, by dividing the basis weight [g / m 2 by the thickness [m], the density [g / m 3 of the sheet S can also be calculated.

[0117] When detecting the grain direction of the sheet S, for example, as a media sensor, an imaging device is used. The transmitted image when irradiating LED light from the back side of the conveyed sheet S is captured, and the captured transmitted image is compared with a reference image previously stored in the main body control unit 203 to detect the grain direction of the sheet S. Alternatively, as a media sensor, an ultrasonic measurement device is used, and the reflection waveform when irradiating the sheet S with ultrasonic waves is measured, and the grain direction of the sheet S can also be detected by comparing it with a reference waveform previously stored in the main body control unit 203.

[0118] When detecting the surface smoothness of the sheet S, a surface property sensor that discriminates the surface characteristics of the sheet S using optical reflection characteristics can be used. Generally, the reflection characteristics of a sheet S with low smoothness (rough surface) such as plain paper or matte paper are completely diffused. On the other hand, for a sheet S with high smoothness (high glossiness) such as gloss paper, specular reflection and diffusion are mixed. The surface property sensor detects the surface property of the sheet S by utilizing this difference in reflection characteristics.

[0119] When detecting the type of the sheet S, a paper type discrimination algorithm that discriminates the type of the sheet S using the density, surface property (specular reflected light, diffused light), basis weight, etc. of the sheet S is used.

[0120] Also, by using a moisture meter that detects the moisture content of the sheet S as a media sensor, the ink amount of the sheet S can be detected.

[0121] In the above embodiment, an inkjet recording apparatus is exemplified as the image forming apparatus 200. However, an electrophotographic printer or a copying machine can also be used as the image forming apparatus 200. In the inkjet recording method of discharging ink onto the sheet S, the conveyance load of the sheet S is more likely to change than in the electrophotographic method. Therefore, the present invention is particularly useful for the sheet post-processing apparatus 1 to which an inkjet recording apparatus is connected as the image forming apparatus 200.

Industrial Applicability

[0122] The present invention can be used for a sheet post-processing apparatus that performs predetermined post-processing on a plurality of sheets.

Explanation of Signs

[0123] 1 Sheet post-processing apparatus 2 Sheet inlet 3 First sheet conveyance path 4 First sheet discharge unit 5 Second sheet conveyance path 6 Second sheet discharge unit 10 Post-processing control unit (control unit) 42 First discharge roller pair 43 First discharge tray 521 Processing tray 523 Processing tray cursor 54 Loading roller pair (conveying member) 55 Alignment member 56 Paddle holder 57 Alignment paddle 571 Paddle body 572 Paddle part 58 Support member 71 Staple part (processing part) 73 Reference plate 80 Discharge tray cursor 92 Sheet binding unit 200 Image forming apparatus 202 Operation Panel (Input Section) 203 Main Control Section M2 Holder Drive Motor S Sheet

Claims

1. A conveying member for conveying a sheet, A processing tray on which a plurality of the sheets carried in along a predetermined loading direction by the conveying member are stacked, A processing unit that performs a predetermined post-processing on the sheets stacked on the processing tray, An outlet through which the sheets on the processing tray are discharged, A discharge tray on which the sheets discharged from the outlet are stacked, A discharge member that conveys the sheets on the processing tray toward the outlet and discharges them to the discharge tray through the outlet, A pair of processing tray cursor that can reciprocate in the width direction orthogonal to the sheet conveying direction on the processing tray and sandwich and align the sheet in the width direction, A pair of discharge tray cursor that can reciprocate in the width direction on the discharge tray and sandwich and align the sheet in the width direction, A control unit that controls the driving of the processing tray cursor and the discharge tray cursor, In a sheet post-processing apparatus comprising: When the control unit performs alignment processing on the sheet in a state where the rear end portion of the sheet is placed on the processing tray and the front end portion protrudes above the discharge tray from the outlet, Narrow the interval between the pair of discharge tray cursor from an initial interval larger than the size of the sheet in the width direction to a first interval narrower than the initial interval and larger than the size of the sheet in the width direction, and sandwich and align the front end portion of the sheet in the width direction, which is a front end alignment process; Narrow the interval between the pair of processing tray cursor from the initial interval to a second interval substantially the same as the size of the sheet in the width direction, and sandwich and align the rear end portion of the sheet in the width direction, which is a rear end alignment process; Execute, A sheet post-processing apparatus characterized in that the first interval is adjusted based on output information regarding the characteristics of the sheet.

2. An image is formed on the sheet using ink, The control unit adjusts the first interval based on at least one of the printing rate of the sheet, which is output information regarding the characteristics of the sheet, or the image pattern recorded by the ink. The sheet post-processing apparatus according to claim 1.

3. The control unit widens the first interval as the printing rate of the sheet increases. The sheet post-processing apparatus according to claim 2.

4. The sheet post-processing apparatus according to claim 1, wherein the control unit adjusts the first interval based on the degree of skew of the sheet estimated from the output information regarding the characteristics of the sheet.

5. The sheet post-processing apparatus according to claim 4, wherein the control unit widens the first interval as the degree of skew of the sheet increases.

6. The sheet post-processing apparatus according to claim 4, wherein the control unit widens the first interval as the size of the sheet in the width direction becomes larger than the size in the carrying direction.

7. The sheet post-processing apparatus according to claim 4, wherein the control unit widens the first interval as the surface smoothness of the sheet increases.

8. The sheet post-processing apparatus according to claim 1, wherein the control unit performs the front-end alignment process and the rear-end alignment process each time one sheet is loaded on the processing tray.

9. The sheet post-processing apparatus according to claim 1, wherein the control unit executes the rear-end alignment process after executing the front-end alignment process.

10. The sheet post-processing apparatus according to claim 1, wherein when the control unit discharges the sheet onto the discharge tray, the control unit makes the interval in the width direction between the pair of discharge tray carriages larger than the first interval.

11. The sheet post-processing apparatus according to claim 1, wherein when performing shift discharge in which the sheet on the processing tray is shifted in the width direction and then discharged onto the discharge tray, the control unit moves the pair of processing tray carriages in the shift direction of the sheet, and in conjunction with the movement of the pair of processing tray carriages, moves the pair of discharge tray carriages in the shift direction.

12. The pair of discharge tray carriages are provided so as to be movable in the width direction and the vertical direction. The control unit When aligning the sheet on the discharge tray, the control unit arranges the pair of discharge tray carriages at a first position facing the side surface of the sheet loaded on the discharge tray. When aligning the sheet on the processing tray, the control unit arranges the pair of discharge tray carriages at a second position above the first position and facing the side surface of the front end portion of the sheet loaded on the processing tray. The sheet post-processing apparatus according to claim 1.

13. The sheet post-processing apparatus according to claim 1, wherein the processing unit is a stapling unit that performs a stapling process of stapling predetermined positions of a plurality of the sheets stacked on the processing tray with staple pins.

14. An image forming apparatus that forms an image on a sheet, and the sheet post-processing apparatus according to any one of claims 1 to 13 that performs predetermined post-processing on the sheet on which the image is formed by the image forming apparatus. An image forming system comprising the same.

15. The image forming system according to claim 14, further comprising an input unit that inputs output information regarding characteristics of the sheet.

16. The image forming system according to claim 15, wherein the first interval between the pair of discharge tray carousels can be adjusted at an arbitrary timing by an input operation to the input unit.

Images