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

Abstract

To provide a sheet post-processing device capable of improving alignment of a sheet having an image printed using ink, regardless of the direction of a print surface of the sheet, and an image formation system with the same.SOLUTION: A sheet post-processing device comprises a conveyance member, a processing tray, a processing part, a reference plate, an alignment member, a holder drive part, and a control part. The alignment member comprises a paddle holder supported swingably along a carrying-in direction, and an alignment paddle supported rotatably at a swing end of the paddle holder. The holder drive part reciprocates between a reference position where the alignment paddle retracts above the sheet in the top position loaded on the processing tray and an operation position where it comes into contact with the top surface of the sheet. The control part corrects a set value of the operation position, the set value being set according to the number of sheets carried onto the processing tray, in accordance with the sheet in the top position loaded onto the processing tray and the direction of a print surface of a new sheet carried onto the processing tray.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a sheet post-processing apparatus 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 apparatus 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 binding process of binding the stacked sheet bundle together with staples, 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 apparatus, a processing tray is provided on which a predetermined number of sheets after image formation are stacked. Then, a binding process, a shift discharge process (sorting process), and the like are performed on the plurality of sheets stacked on the processing tray. In addition, in order to smoothly perform the binding process and the shift discharge process, etc., the sheets on the processing tray are aligned using an aligning member such as an alignment paddle.

[0004] Patent Document 1 discloses a sheet processing apparatus including a compile tray that receives and stacks conveyed sheets, a vertical reference wall that aligns the sheets by aligning the rear ends of the sheets stacked on the compile tray, and a vertical aligning unit that applies a predetermined conveying force to the sheets sequentially supplied to the compile tray and presses the sheets against the vertical reference wall. The compile paddle of the vertical aligning unit changes the reference position in the thickness direction of the sheets stacked on the compile tray.

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 reference position of the paddle can be changed to two positions: a lower position where a small number of sheets are loaded on the tray, and an upper position where a predetermined number or more of sheets are loaded on the tray. However, since the reference position of the paddle can only be changed in two steps, it is not possible to stably convey the sheets to the vertical reference wall with an appropriate conveying force according to the number of sheets loaded, and there is a risk of sheet misalignment.

[0007] Also, in the case of sheets printed with an image by an inkjet method, since the appropriate conveying force varies depending on the ink amount and the combination of the printed surfaces of the sheets loaded on the tray and the sheets carried into the tray, there is a problem that the sheets cannot be properly aligned only with the setting according to the number of sheets loaded.

[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 sheets regardless of the orientation of the printed surface of sheets printed with an image using ink, and an image forming system including the same.

Means for Solving the Problems

[0009] In order 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 reference plate, an alignment member, a holder drive unit, 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 reference plate abuts against the edge on the downstream side in the alignment direction, which is the direction opposite to the loading direction of the sheets loaded on the processing tray, to align the sheets in the loading direction. The alignment member includes an alignment paddle disposed above the processing tray and having a paddle holder swingably supported along the loading direction, a paddle body rotatably supported at the swing end of the paddle holder, and a paddle portion protruding radially from the paddle body, and assists in aligning the sheets by moving the sheets loaded on the processing tray in a direction approaching the reference plate. The holder drive unit reciprocates the alignment paddle between a reference position where the paddle portion retracts above the uppermost sheet loaded on the processing tray and an operating position where it contacts the upper surface of the sheet by swinging the paddle holder. The control unit controls the holder drive unit. The control unit continuously moves the operating position of the alignment paddle in a direction away from the processing tray as the number of sheets loaded onto the processing tray increases. The control unit corrects the set value of the operating position set according to the number of sheets loaded, according to the orientation of the printed surface of the uppermost sheet loaded on the processing tray and the new sheet to be loaded onto the processing tray.

Advantages of the Invention

[0010] According to the first configuration of the present invention, regardless of the number of sheets loaded, the contact state of the paddle portion with respect to the upper surface of the sheet can always be maintained constant. Therefore, the sheets loaded on the processing tray can be stably moved in the loading direction, and the edges of the sheets can be abutted against the reference plate for alignment. Further, by correcting the set value of the operating position set according to the number of sheets loaded, according to the orientation of the printed surface of the uppermost sheet loaded on the processing tray and the new sheet to be loaded onto the processing tray, the sheets can be stably loaded onto and aligned on the processing tray without being affected by the orientation of the printed surface of the sheets.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0012] [1. Configuration of the 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 including 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 above 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 discharging 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 input sheet size information by operating the operation panel 202. 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 supervises the operation of the entire image forming apparatus 200 and controls each part of the image forming apparatus 200.

[0015] The sheet post-processing apparatus 1 is detachably connected to the side surface of the image forming apparatus 200. The sheet post-processing apparatus 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 apparatus 1 is not limited to performing post-processing on a sheet automatically conveyed from the image forming apparatus 200, and may convey a 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 Apparatus] FIG. 2 is a side cross-sectional view schematically showing the configuration of the sheet post-processing apparatus 1 of the present embodiment. As shown in FIG. 2, the sheet post-processing apparatus 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 apparatus 1 facing the image forming apparatus 200. The sheet conveyed from the image forming apparatus 200 toward the sheet post-processing apparatus 1 passes through the sheet inlet 2 and is carried into the interior of the sheet post-processing apparatus 1.

[0018] The first sheet conveyance path 3 extends substantially horizontally in a direction away from the image forming apparatus 200 (left direction in FIG. 2) from the sheet inlet 2 to the first sheet discharge unit 4. The direction from the sheet inlet 2 toward the first sheet discharge unit 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 apparatus 1 from the sheet inlet 2 toward the downstream side in the sheet conveyance direction.

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

[0020] The first row outlet 41 is located at the downstream end of the first sheet conveyance path 3 in the sheet conveyance direction. The first discharge roller pair 42 is disposed at the first row outlet 41. The first discharge tray 43 is located on the downstream side of the first row outlet 41 in the sheet conveyance direction. The sheet that has been conveyed through the first sheet conveyance path 3 and reached the first row outlet 41 is discharged onto the first discharge tray 43 through the first row outlet 41 by the first discharge roller pair 42. The first discharge tray 43 is one of the final discharge locations for the sheets that have 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 (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 of the second sheet conveyance path 5 in the sheet conveyance direction. The second sheet conveyance path 5 has a plurality of conveyance roller pairs 5r and conveys the sheet conveyed through the first sheet conveyance path 3 by branching it at the first branch portion 31 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 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 branches from the first sheet conveyance path 3 and guides it to the second sheet conveyance path 5. Further, the first switching guide 311 rotates to a position that guides the sheet that has been subjected to folding processing 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 unit 6 is provided above the first sheet discharge unit 4 on the side of the sheet post-processing apparatus 1 opposite to the side facing the image forming apparatus 200. The second sheet discharge unit 6 is disposed at the downstream end in the sheet conveyance direction of the second sheet conveyance path 5. The second sheet discharge unit 6 includes a second discharge port 61, a second discharge roller pair 62, and a second discharge tray 63.

[0024] The second discharge port 61 is located at the downstream end in the sheet conveyance direction of the second sheet conveyance path 5. The second discharge roller pair 62 is disposed at the second discharge port 61. The second discharge tray 63 is located on the downstream side in the sheet conveyance direction of the second discharge port 61. The sheet that has been conveyed through the second sheet conveyance path 5 and reached the second discharge port 61 is discharged onto the second discharge tray 63 through the second discharge port 61 by the second discharge roller pair 62. The second discharge tray 63 is one of the final discharge locations for the sheets that have been post-processed by the sheet post-processing apparatus 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 extends downward from a second branch portion 32 on the first sheet conveyance path 3 to a third sheet discharge unit 8. The direction from the second branch portion 32 toward the third sheet discharge unit 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 in the sheet conveyance direction of the third sheet conveyance path 7. 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 unit 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 to the first discharge port 41 along the first sheet conveyance path 3, 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 portion 8 is provided on the side surface of the sheet post-processing apparatus 1 opposite to the side surface facing the image forming apparatus 200, below the first sheet discharge portion 4 (near the lower end of the sheet post-processing apparatus 1). The third sheet discharge portion 8 has 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 in the sheet conveyance direction of the third sheet conveyance path 7. 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 in the sheet conveyance direction of the third discharge port 81. The sheet conveyed on 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 on 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 closest upstream of the first sheet discharging unit 4 with respect to the sheet conveyance direction of the first sheet conveyance path 3. The sheet binding unit 92 performs staple processing (binding processing) on a stack of a plurality of sheets to bind the stack of sheets. The detailed configuration of the sheet binding unit 92 will be described later.

[0032] The sheet folding unit 100 is disposed downstream of the punching unit 91 and upstream 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 folding processing on a single sheet to form a fold line. The sheet folding unit 100 can perform folding processing such as double folding, Z-folding, outside triple folding, inside triple folding, etc. on a single sheet.

[0033] The production unit 94 is disposed closest upstream of the third sheet discharging unit 8 with respect to the sheet conveyance direction of the third sheet conveyance path 7. The production unit 94 has a middle folding part 941 and a middle binding part 942. The production unit 94 performs middle folding processing and middle binding processing of bending and binding a substantially central part in the sheet conveyance direction on a stack of 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, based on a control program and data stored in the storage unit using the CPU, controls the operations of the respective components provided in the sheet post-processing apparatus 1 to perform processing related to the functions of the sheet post-processing apparatus 1. Each of the first sheet conveyance path 3, the first sheet discharging unit 4, the second sheet conveyance path 5, the second sheet discharging unit 6, the third sheet conveyance path 7, the third sheet discharging 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] [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 binding unit 92 includes a processing tray 521, a stapling 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). A discharge lower roller 421 constituting the first discharge roller pair 42 is supported on the downstream side in the loading direction of the processing tray 521 (lower left side in FIG. 3).

[0038] The processing tray 521 includes a tray central portion 522 and a width restricting member 523. The tray central portion 522 is disposed at the central portion in the sheet 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] The width regulating members 523 are arranged in a pair so as to sandwich the center portion 522 of the tray in the sheet width direction. The width regulating members 523 regulate the position of the sheet S carried into the processing tray 521 in the sheet width direction. The width regulating members 523 are made of a thin plate-like member similar to the center portion 522 of the tray, and have side walls erected upward at the ends in the sheet width direction. A guide groove 524 extending along the sheet width direction is formed in the processing tray 521. The width regulating members 523 are reciprocally movable in the sheet 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 carried into the processing tray 521, the width regulating members 523 are reciprocally moved by the drive mechanism. As a result, the sheets stacked on the processing tray 521 are aligned in the sheet width direction.

[0040] The stapling unit 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 stapling unit 71 is movable in the sheet width direction (the direction of arrow AA') orthogonal to the carrying direction along the edge of the sheet by the driving force of the stapling unit drive motor M1, and performs stapling on the bundle of sheets.

[0041] As shown in FIG. 4, the stapling unit 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 stapling unit 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 plates 73 are fixed at three positions spaced apart in the sheet 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 plates 73 have a substantially U-shaped cross section with the upstream side in the alignment direction (the upper left side in FIG. 4) open in a view perpendicular to the sheet width direction. The reference plates 73 abut against the edge of the sheet carried into the processing tray 521 and align the sheet in the carrying direction.

[0043] [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 loading rollers 54 is arranged above the processing tray 521. The pair of loading rollers 54 is composed of a loading upper roller 54a and a loading lower roller 54b.

[0044] A sheet detection sensor 93 is arranged near the pair of loading rollers 54. The sheet detection sensor 93 detects the timing when the sheet S passes through the pair of loading 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] A tapping member 53 and an alignment member 55 are provided on the downstream side (the left side in FIG. 5) of the pair of loading rollers 54 with respect to the loading direction of the sheet S. The tapping member 53 is supported so as to be swingable along the loading 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 pair of loading rollers 54, thereby tapping the sheet S downward and aligning it along the processing tray 521.

[0046] The alignment members 55 are arranged at a plurality of positions (four positions in this embodiment) along the sheet width direction (the direction perpendicular to the paper surface of FIG. 5). The alignment member 55 moves (switches back) the sheet S loaded on the processing tray 521 in the alignment direction approaching the reference plate 73 to assist in aligning the sheet S. The alignment member 55 includes a paddle holder 56 and an alignment paddle 57.

[0047] The paddle holder 56 is supported above the processing tray 521 so as to be swingable along the sheet S feeding direction. 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 rotation direction and the rotation amount (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 (alignment paddle 57) is provided. The post-processing control unit 10 estimates the height (distance from the processing tray 521) of the alignment 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 alignment paddle 57. The alignment paddle 57 has a paddle main body 571 and a paddle portion 572. The paddle main 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 main body 571 and is rotatably supported at the swing end (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 point-symmetrical to the outer peripheral surface of the paddle main body 571 around the fulcrum portion 571a.

[0049] A rotational driving force in the direction of feeding the sheet S in the alignment direction (counterclockwise direction in FIG. 5) is input to the alignment paddle 57 by a driving source such as a motor (not shown). By the paddle portion 572 of the alignment paddle 57 contacting and rotating on 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 swing 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 stacked 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 sheet 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 at a predetermined interval with respect to the central portion of the processing tray 521 in the sheet width direction.

[0052] The support member 58 is movable between a protruding position (the solid line position in FIG. 5) protruding to the downstream side in the discharge direction (the left side in FIG. 5) from the first discharge roller pair 42 and a retracted position (the broken line position in FIG. 5) retracted to the upstream side in the discharge direction (the 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 a state immediately before the sheet S is carried onto the processing tray 521. The paddle holder 56 is swung upward (clockwise), and the alignment paddle 57 is disposed at a position separated from the processing tray 521 (reference position). Further, the nip between the discharge lower roller 421 and the discharge upper 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.

[0054] Then, 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 direction). As a result, 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, the paddle portion 572 can be surely brought 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. Adjustment Control of Operating Position of Alignment Paddle] Next, the adjustment control of the operating position of the alignment paddle 57 will be described. In the present embodiment, the operating position of the alignment paddle 57 is changed based on the number of sheets S carried onto the processing tray 521. More specifically, as the number of sheets S carried onto the processing tray 521 increases, the operating position of the alignment paddle 57 is separated from the processing tray 521.

[0056] Specifically, the post-processing control unit 10 counts the number of sheets S carried onto the processing tray 521. Then, a control signal is transmitted to the holder drive motor M2 to move the stop position of the paddle holder 56 upward every time one sheet (or a predetermined number of sheets) of the sheet S is carried in. As a result, the operating position of the alignment paddle 57 also continuously moves upward.

[0057] According to the above configuration, the operating position of the alignment paddle 57 also rises by the amount that the number of sheets S carried onto the processing tray 521 increases and the upper surface position of the sheet S rises. As a result, regardless of the number of sheets S carried in, the contact state of the paddle portion 572 with respect to the upper surface of the sheet S can be maintained constant. Therefore, from a state where the number of sheets S loaded on the processing tray 521 is small to a state where the maximum number of sheets that can be loaded is loaded, the sheet S can be stably moved in the carry-in direction, and the edge of the sheet S can be abutted against the reference plate 73 for alignment.

[0058] In addition, the conveying force of the alignment paddle 57 required for aligning the sheet S varies greatly depending on the type of the sheet S (size, thickness, basis weight, grain direction, surface smoothness). When the sheet S is paper, the fibers constituting the sheet S tend to be aligned along the direction in which the paper flows in the paper-making machine. The direction in which these fibers are aligned is referred to as the "grain direction" of the sheet S.

[0059] Further, when the image forming apparatus 200 connected to the sheet post-processing apparatus 1 is an inkjet recording apparatus, the conveying load when drawing the sheet S into the processing tray 521 also varies depending on the amount of ink used for image recording. Therefore, it may be difficult to stably convey and align the sheet S only by setting the action position according to the number of sheets S loaded.

[0060] Therefore, in the present embodiment, the action position of the alignment paddle 57 is adjusted based on the output information regarding the characteristics of the sheet S. Specifically, information regarding the output information (type of the sheet S and amount of ink) regarding the characteristics of the sheet S is input from the image forming apparatus 200. The post-processing control unit 10 adjusts the action position of the alignment paddle 57 according to the input output information regarding the characteristics of the sheet S.

[0061] FIG. 7 is a diagram showing a state in which a new sheet S2 is carried into the uppermost sheet S1 stacked on the processing tray 521. FIGS. 8(a) and 8(b) are diagrams showing the printing states of the front surface S1f and the back surface S1r of the uppermost sheet S1 stacked on the processing tray 521, respectively. FIGS. 9(a) and 9(b) are diagrams showing the printing states of the front surface S2f and the back surface S2r of the sheet S2 carried into the processing tray 521, respectively. With reference to FIGS. 7 to 9, the relationship between the orientation of the printing surface of the sheets S1 and S2 and the conveying force of the alignment paddle 57 required for aligning the sheet S2 will be described.

[0062] As shown in FIG. 8(a), a printing area P is formed on the front surface S1f of the sheet S1. On the other hand, as shown in FIG. 8(b), no printing area P is formed on the back surface S1r of the sheet S1. That is, the sheet S1 is stacked on the processing tray 521 with the printing surface facing upward.

[0063] As shown in FIG. 9(a), no printing area P is formed on the front surface S2f of the sheet S2. On the other hand, as shown in FIG. 9(b), a printing area P is formed on the back surface S2r of the sheet S2. That is, the sheet S2 is carried onto the processing tray 521 with the printing surface facing downward.

[0064] In this case, as shown in FIG. 7, when the sheet S2 is carried onto the topmost sheet S1 loaded on the processing tray 521, the printing surfaces of the sheets S1 and S2 face each other. As a result, it is considered that the frictional force between the sheets S1 and S2 increases.

[0065] Therefore, in the present embodiment, the action position of the alignment paddle 57 is corrected according to the orientation of the printing surfaces of the topmost sheet S1 loaded on the processing tray 521 and the new sheet S2 to be carried onto the processing tray 521. Specifically, when the printing surfaces of the sheets S1 and S2 face each other, the action position of the alignment paddle 57 is corrected in a direction closer to the processing tray 521 compared to when the printing surfaces of the sheets S1 and S2 do not face each other.

[0066] According to the above configuration, the action position of the alignment paddle 57 determined based on the output information regarding the number of sheets S loaded on the processing tray 521 and the characteristics of the sheets S is appropriately corrected according to the orientation (combination) of the printing surfaces of the topmost sheet S1 loaded on the processing tray 521 and the new sheet S2 to be carried onto the processing tray 521. Therefore, the sheet S can be stably carried onto and aligned on the processing tray 521 without being affected by the orientation of the printing surface of the sheet S.

[0067] FIG. 10 is a flowchart showing an example of binding process control executed in the sheet post-processing apparatus 1 of the present embodiment. FIG. 11 is a flowchart showing an example of adjustment control of the action position of the alignment paddle 57 in FIG. 10. With reference to FIGS. 1 to 9 as necessary, the adjustment procedure for the action position of the alignment paddle 57 will be described along the steps of FIGS. 10 and 11. In the initial state, it is assumed that the action position of the alignment paddle 57 is set to a reference action position according to the reference output information (for example, the output information 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.

[0068] When a binding process command for the sheet S is input from the main 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 control unit 203 in association with the information regarding the corresponding type of the sheet S. Thereby, the main 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.

[0069] The information regarding the ink amount is calculated by the main 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 control unit 203.

[0070] The post-processing control unit 10 (see FIG. 2) determines whether it is necessary to adjust the action position of the alignment paddle 57 based on the input output information of the sheet S (step S2). If it is determined that the adjustment of the action position is necessary (Yes in step S2), the post-processing control unit 10 adjusts the action position of the alignment paddle 57 from the reference action position (step S3). Specifically, as shown in FIG. 11, first, the action position is set based on the output information of the sheet S (step S31).

[0071] For example, when the size, thickness, basis weight, and surface frictional force of the sheet S increase, the conveying force required for the movement of the sheet S increases. Specifically, when the sheet S is European-made paper, it has less surface smoothness and a greater tendency for friction between sheets compared to Japanese or US-made paper. Also, when the grain direction of the sheet S is parallel to the sheet width direction, the conveying force required for the movement of the sheet S is greater than when the grain direction of the sheet S is parallel to the loading direction. Therefore, when the size, thickness, basis weight, and surface frictional force of the sheet S are greater than the reference output information, or when the grain direction of the sheet S is parallel to the sheet width direction, the acting position of the alignment paddle 57 is adjusted in a direction closer to the processing tray 521 than the reference acting position.

[0072] On the other hand, when the size, thickness, basis weight, and surface frictional force of the sheet S are smaller than the reference output information, or when the grain direction of the sheet S is parallel to the loading direction, the acting position of the alignment paddle 57 is adjusted in a direction farther from the processing tray 521 than the reference acting position. The amount of adjustment from the reference acting position is determined based on a correction table that defines the relationship between the size, thickness, basis weight, grain direction, surface smoothness of the sheet S and the corresponding acting position (drive pulses of the holder drive motor M2).

[0073] Also, when the amount of ink used for image recording increases, the weight of the sheet S increases, so the conveying force required for the movement of the sheet S increases. Therefore, when the ink amount is greater than the reference output information, the acting position of the alignment paddle 57 is adjusted in a direction closer to the processing tray 521 than the reference acting position. On the other hand, when the ink amount is smaller than the reference output information, the acting position of the alignment paddle 57 is adjusted in a direction farther from the processing tray 521 than the reference acting position. The amount of adjustment from the reference acting position is determined based on a correction table that defines the relationship between the ink amount and the corresponding acting position (drive pulses of the holder drive motor M2).

[0074] Next, the post-processing control unit 10 determines whether the printing surfaces of the topmost sheet S1 on the processing tray 521 and the new sheet S2 carried onto the sheet S2 face each other (step S32). The orientations of the printing surfaces of the sheets S1 and S2 are determined by whether the sheets S1 and S2 are single-sided printed or double-sided printed. Whether it is single-sided printing or double-sided printing is transmitted from the main body control unit 203 as output information of the sheets S1 and S2.

[0075] When the printing surfaces of the topmost sheet S1 and the new sheet S2 face each other (Yes in step S32), the value obtained by adding the correction value α to the set value set in step S31 is used as the acting position (step S33). That is, the alignment paddle 57 is corrected in the direction approaching the processing tray 521 from the set acting position. When the printing surfaces of the topmost sheet S1 and the new sheet S2 do not face each other (No in step S32), the set value set in step S31 is used as the acting position (step S34).

[0076] When it is determined that adjustment of the acting position is not necessary (No in step S2), the post-processing control unit 10 proceeds to the next step without changing the acting position of the alignment paddle 57 from the reference acting position.

[0077] Next, the post-processing control unit 10 starts to carry the sheet S carried into the sheet post-processing apparatus 1 through the sheet inlet 2 onto 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 pair of carrying rollers 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 lowers the paddle holder 56 downward by a predetermined amount by the holder drive motor M2. As a result, the alignment paddle 57 moves to the acting position and the paddle portion 572 contacts the upper surface of the sheet S. By rotating the alignment paddle 57 in this state, the sheet S is drawn along the processing tray 521 in the alignment direction (arrow B direction).

[0078] Thereafter, the sheet S is further sent downstream in the alignment direction by the alignment paddle 57, aligned in the sheet width direction by the width regulating member 523 (see FIG. 3), and aligned and stacked in the carrying direction by the reference plate 73.

[0079] The post-processing control unit 10 counts the number of sheets S carried into the processing tray 521 (step S5). Then, every time one sheet (or a predetermined number of sheets) of the sheet S is carried in, the stop position of the paddle holder 56 is moved upward, and the acting position of the alignment paddle 57 is continuously moved upward.

[0080] 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 a predetermined number of sheets S have not been carried in (No in step S6), the process returns to step S4, and the carrying of the sheet S into the processing tray 521 and the counting of the number of carried-in sheets are continued.

[0081] If a predetermined number of sheets S have been 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 and performs a stapling process on the plurality of sheets S aligned by the reference plate 73 (step S7).

[0082] Next, the post-processing control unit 10 causes the first discharge roller pair 42 to come into contact (form a nip) and rotates the first discharge roller pair 42 in the discharge direction. As a result, the bundle of sheets S that has been stapled is discharged to the first discharge tray 43 (both see FIG. 2) by the first discharge roller pair 42 (step S8). After discharging the bundle of sheets S, the post-processing control unit 10 transmits a control signal to the stapler unit drive motor M1 to move the stapler unit 71 to the standby position (step S9).

[0083] Thereafter, the post-processing control unit 10 determines whether the binding process has ended (step S10). If the binding process is ongoing (No in step S10), it returns to step S4 and repeats the operations of loading the sheet S onto the processing tray 521 and counting the number of loaded sheets, executing the stapling process, discharging the stack of sheets, and moving the stapler unit 71 to the standby position (steps S4 to S10). If the binding process has ended (Yes in step S10), the process ends as it is.

[0084] According to the control example shown in FIG. 10, based on the output information of the sheet S, the operating position of the alignment paddle 57 is adjusted to an optimal position. Therefore, the sheet S can be stably conveyed and aligned without being affected by the type of the sheet S and the amount of ink when an image is recorded by the inkjet recording apparatus.

[0085] Also, by continuously moving the operating position upward according to the number of sheets S loaded onto the processing tray 521, the contact state of the paddle portion 57 with respect to the upper surface of the sheet S can be kept constant regardless of the number of sheets S loaded.

[0086] Furthermore, by correcting the operating position of the alignment paddle 57 according to the orientation (combination) of the printing surface of the uppermost sheet S1 on the processing tray 521 and the new sheet S2 loaded onto the sheet S2, the operating position of the alignment paddle 57 can be appropriately corrected regardless of whether the sheet S is single-sided printed or double-sided printed.

[0087] The embodiments of the present invention have been described above. 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 operating position of the alignment paddle 57 at an arbitrary timing. For example, a conveyance force adjustment mode for switching the conveyance force of the alignment paddle 57 to three levels of "small", "medium", and "large" 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.

[0088] Also, in the above embodiment, an example of performing a binding process on the sheet S stacked on the processing tray 521 by the sheet binding unit 92 has been shown. However, the present invention is not limited thereto, and a configuration may be adopted in which a shift discharge process or a folding process is performed on the sheet S stacked on the processing tray 521.

[0089] Further, 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 may be disposed at an arbitrary position in the sheet conveyance path from the image forming apparatus 200 to the sheet post-processing apparatus 1, and 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 into the sheet post-processing apparatus 1 from the image forming apparatus 200 can be detected by the media sensor.

[0090] For example, when detecting the thickness of the sheet S, a laser coaxial displacement meter that sandwiches the sheet S between two optical sensors can be used as the media sensor.

[0091] When detecting the basis weight of the sheet S, a basis weight sensor that measures the basis weight based on the light transmittance of the sheet S can be used as the media sensor. 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.

[0092] When detecting the grain direction of the sheet S, for example, an imaging device is used as the media sensor, and a transmission image is captured when irradiating LED light from the back side of the conveyed sheet S, and the captured transmission image is compared with a reference image stored in advance in the main body control unit 203 to detect the grain direction of the sheet S. Alternatively, an ultrasonic measurement device can be used as the media sensor, and the reflection waveform when irradiating ultrasonic waves on the sheet S is measured, and the grain direction of the sheet S can also be detected by comparing it with a reference waveform stored in advance in the main body control unit 203.

[0093] When detecting the surface smoothness of the sheet S, a surface property sensor that discriminates the surface property of the sheet S using the optical reflection property can be used. Generally, the reflection property of a sheet S with low smoothness (rough surface) such as plain paper or matte paper is a perfect diffusion. On the other hand, in a sheet S with high smoothness (high glossiness) such as gloss paper, regular reflection and diffusion are mixed. The surface property sensor detects the surface property of the sheet S by utilizing this difference in reflection property.

[0094] 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 (regular reflection light, diffused light), basis weight, etc. of the sheet S is used.

[0095] Also, by using a moisture meter that detects the moisture content of the sheet S as the media sensor, the ink amount of the sheet S can be detected.

[0096] In the above-described 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

[0097] 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

[0098] 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 521 Processing tray 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 92 Sheet binding unit 200 Image forming apparatus 202 Operation panel (input unit) 203 Main body control unit M2 Holder drive motor S Sheet

Claims

1. A conveying member that conveys a sheet on which an image is formed using ink, 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 predetermined post-processing on the sheet stacked on the processing tray, A reference plate that abuts against an edge on the downstream side in the alignment direction, which is the direction opposite to the loading direction of the sheet loaded on the processing tray, and aligns the sheet in the loading direction, A paddle holder disposed above the processing tray and supported so as to be swingable along the loading direction, An alignment paddle having a paddle body rotatably supported at a swing end of the paddle holder, and one or more paddle portions protruding radially from the paddle body, An alignment member that moves the sheet loaded on the processing tray in the alignment direction to assist in aligning the sheet, A holder driving unit that reciprocates the alignment paddle between a reference position where the paddle portion is retracted above the uppermost sheet stacked on the processing tray and an operating position where it contacts the upper surface of the sheet by swinging the paddle holder, A control unit that controls the holder driving unit, In a sheet post-processing apparatus comprising: The control unit continuously moves the operating position of the alignment paddle in a direction away from the processing tray as the number of sheets loaded on the processing tray increases, A sheet post-processing apparatus, wherein a set value of the operating position set according to the number of sheets loaded is corrected according to the orientation of the printing surface of the uppermost sheet stacked on the processing tray and a new sheet to be loaded on the processing tray.

2. The sheet post-processing apparatus according to claim 1, wherein the control unit corrects the set value of the operating position in a direction approaching the processing tray when the printing surfaces of the uppermost sheet stacked on the processing tray and a new sheet to be loaded on the processing tray face each other.

3. The sheet post-processing apparatus according to claim 1, wherein the control unit sets the operating position of the alignment paddle based on output information regarding the number of sheets loaded and the characteristics of the sheets.

4. The output information regarding the characteristics of the sheet includes at least one of the size, thickness, basis weight, grain direction, surface smoothness of the sheet, and the amount of ink used for image formation on the sheet, and the sheet post-processing apparatus according to claim 3 is characterized in that.

5. The processing unit is a stapling unit that performs a stapling process of stapling a predetermined position of a plurality of the sheets stacked on the processing tray with staples, and the sheet post-processing apparatus according to claim 1 is characterized in that.

6. An image forming apparatus that discharges ink onto a sheet to form an image, The sheet post-processing apparatus according to any one of claims 1 to 5, which performs predetermined post-processing on the sheet on which an image is formed by the image forming apparatus, An image forming system comprising.

7. An image forming apparatus that forms an image on a sheet, The sheet post-processing apparatus according to claim 3, which performs predetermined post-processing on the sheet on which an image is formed by the image forming apparatus, In an image forming system comprising, The image forming system further includes an input unit that inputs output information regarding the characteristics of the sheet, and is characterized in that.

8. The image forming system according to claim 7, wherein the set value of the operating position of the alignment paddle can be corrected at an arbitrary timing by an input operation to the input unit, and is characterized in that.

Images