Sheet discharge device and sheet post-processing device including the same and image forming device

Abstract

To provide a sheet discharge device capable of improving a discharge property of a sheet with a large curl irrespective of the width direction size of the sheet, to provide a sheet post-processing device including the same, and to provide an image forming device.SOLUTION: A sheet discharge device includes a sheet discharge port, a discharge member, a sheet discharge tray, and a blower mechanism. The discharge member is arranged at the sheet discharge port, and conveys a sheet in a discharge direction. The sheet discharge tray is arranged on the downstream side of the sheet discharge port with respect to the discharge direction, and on which sheets discharged from the sheet discharge port are loaded. The blower mechanism includes: a blower port for blowing an airflow from the upper direction with respect to the sheet discharged from the sheet discharge port; and a blower device connected to the blower port, and for generating an airflow. The blower mechanism can adjust an air blowing position of the airflow with respect to the sheet according to the size in the width direction of the sheet.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet discharge device that discharges a sheet after an image has been formed by an image forming apparatus, a sheet post-processing device including the same, and an image forming apparatus. [Background technology]

[0002] Image forming devices such as copiers and printers, and sheet post-processing devices that perform post-processing on sheets, are equipped with a sheet discharge device having a pair of discharge rollers and a discharge tray. After an image is formed on a sheet (paper) by the image forming device, the sheet is discharged onto the discharge tray by the sheet discharge device provided in the image forming device. Alternatively, the sheet is transported into the sheet post-processing device, undergoes a predetermined post-processing, and then is discharged onto the discharge tray by the sheet discharge device provided in the sheet post-processing device.

[0003] Such sheet discharge devices have the problem of poor sheet alignment on the discharge tray due to discharged sheets sticking together, buckling, curling, etc. To address this problem, a method has been adopted in which air is blown by a fan from above the sheet discharge port to stabilize the discharge of sheets.

[0004] Patent Document 1 discloses an image forming apparatus equipped with an air blowing unit that blows air in a direction parallel to the discharge direction of the recording medium onto the upper surface side of the recording medium discharged from the discharge unit. Patent Document 2 discloses a post-processing apparatus that includes a first tray that holds a sheet stack including a preceding sheet and a succeeding sheet, a second tray located downstream of the first tray, a drawing mechanism that transports the succeeding sheet in a drawing direction opposite to the discharge direction and overlaps it on the preceding sheet on the first tray, a second discharge unit that discharges the sheet stack, a first air blowing unit that blows air between the second tray and the lower surface of the preceding sheet, a second air blowing unit that blows air onto upper surfaces of the preceding sheet and the succeeding sheet, and a control unit that controls the first air blowing unit and the second air blowing unit.

[0005] According to the configuration of Patent Document 1, air is blown between the discharged paper and the stacked paper, thereby improving the sticking and buckling of the paper. According to the configuration of Patent Document 2, the first and second air blowing sections blow air onto the bottom and top surfaces of the preceding sheet, thereby preventing the preceding sheet and the following sheet from sticking together. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-184809 [Patent Document 2] Japanese Patent Application Publication No. 2018-177455 Summary of the Invention [Problem to be solved by the invention]

[0007] When discharging a sheet with large curls at both widthwise ends, the curled sheet may clog the sheet discharge port, causing problems with sheet discharge. Also, when blowing air from above the discharged sheet to suppress the curls at both widthwise ends, there is a problem that the position of the widthwise ends changes depending on the sheet size, making it difficult to effectively suppress the curls.

[0008] SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a sheet discharge device capable of effectively improving the discharge performance of a sheet with a large curl, and a sheet post-processing device and an image forming apparatus including the same. [Means for solving the problem]

[0009] In order to achieve the above object, a first configuration of the present invention is a sheet discharge device including a sheet discharge outlet, a discharge member, a sheet discharge tray, and an air blowing mechanism. Sheets are discharged from the sheet discharge outlet. The discharge member is disposed at the sheet discharge outlet and transports the sheets in the discharge direction. The sheet discharge tray is disposed downstream of the sheet discharge outlet in the discharge direction and stacks the sheets discharged from the sheet discharge outlet. The air blowing mechanism blows an air flow onto the sheets discharged from the sheet discharge outlet. The air blowing mechanism has a pair of air blowing ports that blow air from above onto both ends of the sheets in the width direction perpendicular to the discharge direction discharged from the sheet discharge outlet, and an air blowing device connected to the air blowing ports and generating the air flow. The air blowing mechanism is capable of adjusting the blowing position of the air flow relative to the sheets depending on the width size of the sheets. [Effects of the Invention]

[0010] According to the first aspect of the present invention, by adjusting the airflow position according to the width of the sheet discharged onto the sheet discharge tray, it is possible to suppress upward curl that occurs at both widthwise ends of the sheet regardless of the width of the sheet, thereby improving the alignment of the sheet discharged onto the sheet discharge tray. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing the configuration of an image forming system including a sheet post-processing device 1 according to an embodiment of the present invention and an image forming device 200 to which the sheet post-processing device 1 is connected; [Figure 2] FIG. 1 is a side cross-sectional view schematically illustrating a configuration of a sheet post-processing device 1 according to an embodiment of the present invention. [Figure 3] 1 is a perspective view of the periphery of a first sheet discharge unit 4 of a sheet post-processing device 1 according to an embodiment of the present invention; [Figure 4] FIG. 1 is a side cross-sectional view of the first sheet discharge unit 4 and its surroundings of the sheet post-processing device 1 of the present embodiment. [Figure 5] 1 is a perspective view showing a state in which a large-sized sheet S1 is discharged to a first sheet discharge section 4 according to a first embodiment of the present invention, as seen from above; FIG. [Figure 6]1 is a perspective view showing a state in which a small-sized sheet S1 is discharged to a first sheet discharge portion 4 according to a first embodiment, as viewed from above; FIG. [Figure 7] 10 is a perspective view showing a state in which a small-sized sheet S2 is discharged to a first sheet discharge section 4 according to a second embodiment of the present invention, as seen from above; FIG. [Figure 8] 10 is a flowchart showing an example of adjustment control of the air blowing position by the air blowing mechanism 44 in the first sheet discharge section 4 of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] [1. Image formation system configuration]

[0023] Hereinafter, an embodiment 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 device 1 according to an embodiment of the present invention and an image forming device 200 to which the sheet post-processing device 1 is connected.

[0013] 1, 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 image forming apparatus 200. In this embodiment, image forming apparatus 200 is an inkjet recording device provided with a recording head (not shown) for each color, which is provided with a number of nozzle holes that eject ink onto the sheet.

[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, a user can operate the operation panel 202 to input sheet size information. The user can also operate the operation panel 202 to input the number of sheets to be printed and to instruct the start of a print job. The main body control unit 203 supervises the overall operation of the image forming apparatus 200 and controls each unit of the image forming apparatus 200.

[0015] The sheet post-processing device 1 is detachably connected to the side of the image forming apparatus 200. The sheet post-processing device 1 performs post-processing such as punch hole formation and binding on sheets after images have been formed (printed) by the image forming apparatus 200. Note that the sheet post-processing device 1 is not limited to a device that performs post-processing on sheets automatically transported from the image forming apparatus 200, but may also be a device that transports sheets set by a user on a tray (not shown) to a position where the sheets can be post-processed and performs post-processing on the sheets.

[0016] [2. Configuration of sheet post-processing device] 2 is a side cross-sectional view schematically illustrating the configuration of the sheet post-processing device 1 of this embodiment. As shown in FIG. 2, the sheet post-processing device 1 includes a sheet entrance 2, a first sheet transport path 3, a first sheet discharge section 4, a second sheet transport path 5, a second sheet discharge section 6, a third sheet transport path 7, a third sheet discharge section 8, a post-processing section 9, and a post-processing control section (control section) 10.

[0017] The sheet entrance 2 is an opening provided on the side of the sheet post-processing device 1 facing the image forming device 200. A sheet transported from the image forming device 200 to the sheet post-processing device 1 passes through the sheet entrance 2 and is carried into the inside of the sheet post-processing device 1.

[0018] The first sheet transport path 3 extends substantially horizontally from the sheet entrance 2 to the first sheet discharge section 4 in a direction away from the image forming apparatus 200 (to the left in FIG. 2). The direction from the sheet entrance 2 toward the first sheet discharge section 4 is referred to as the sheet transport direction in the first sheet transport path 3. The sheet entrance 2 is located at the upstream end of the first sheet transport path 3 in the sheet transport direction. The first sheet transport path 3 has multiple transport roller pairs 3r, and transports a sheet carried into the sheet post-processing device 1 from the sheet entrance 2 toward the downstream side in the sheet transport direction.

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

[0020] The first discharge outlet 41 is located at the downstream end of the first sheet transport path 3 in the sheet transport direction. The first discharge roller pair 42 is disposed at the first discharge outlet 41. The first discharge tray 43 is located downstream of the first discharge outlet 41 in the sheet transport direction. A sheet that has been transported along the first sheet transport path 3 and reached the first discharge outlet 41 is passed through the first discharge outlet 41 by the first discharge roller pair 42 and discharged onto the first discharge tray 43. The first discharge tray 43 is one of the final discharge locations for sheets that have been post-processed by the sheet post-processing device 1. In addition, sheets that are not post-processed and small-sized sheets are also discharged to the first discharge tray 43.

[0021] The second sheet transport path 5 branches off from a first branching portion (branching portion) 31 on the first sheet transport path 3 and extends horizontally and upward in a direction away from the image forming apparatus 200 (to the left in FIG. 2 ) to the second sheet discharge portion 6. The first branching portion 31 is located downstream of the punching portion 91 in the sheet transport direction of the first sheet transport path 3. The direction from the first branching portion 31 toward the second sheet discharge portion 6 is referred to as the sheet transport direction of the second sheet transport path 5. The first branching portion 31 is located at the upstream end of the second sheet transport path 5 in the sheet transport direction. The second sheet transport path 5 has multiple transport roller pairs 5r, and branches off a sheet transported along the first sheet transport path 3 at the first branching portion 31 to transport the sheet toward the second sheet discharge portion 6.

[0022] The first branching section 31 has a first switching guide 311. The first switching guide 311 rotates between a position where it guides a sheet conveyed on the first sheet conveying path 3 from the sheet entrance 2 side along the first sheet conveying path 3 to the first discharge outlet 41, and a position where it branches off from the first sheet conveying path 3 and guides the sheet to the second sheet conveying path 5. Furthermore, the first switching guide 311 rotates to a position where it guides a sheet that has been folded and passed through a second folding conveying path 106 (described later) to the second sheet conveying 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 section 10.

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

[0024] The second discharge outlet 61 is located at the downstream end of the second sheet transport path 5 in the sheet transport direction. The second discharge roller pair 62 is disposed at the second discharge outlet 61. The second discharge tray 63 is located downstream of the second discharge outlet 61 in the sheet transport direction. A sheet that has been transported along the second sheet transport path 5 and reached the second discharge outlet 61 is passed through the second discharge outlet 61 by the second discharge roller pair 62 and discharged onto the second discharge tray 63. The second discharge tray 63 is one of the final discharge locations for sheets that have been post-processed by the sheet post-processing device 1. In addition, sheets that are not post-processed and small-sized sheets are also discharged to the second discharge tray 63.

[0025] The third sheet transport path 7 branches off from the second branching portion 32 on the first sheet transport path 3 and extends downward to the third sheet discharge portion 8. The direction from the second branching portion 32 toward the third sheet discharge portion 8 is referred to as the sheet transport direction of the third sheet transport path 7. The second branching portion 32 is located downstream of the first branching portion 31 with respect to the sheet transport direction of the first sheet transport path 3, and is located at the upstream end of the third sheet transport path 7 in the sheet transport direction. The third sheet transport path 7 has multiple transport roller pairs 7r, and causes the sheet transported along the first sheet transport path 3 to branch off at the second branching portion 32 and be transported toward the third sheet discharge portion 8.

[0026] The second branching section 32 has a second switching guide 321. The second switching guide 321 rotates between a position where it guides a sheet conveyed on the first sheet conveying path 3 from the sheet entrance 2 side along the first sheet conveying path 3 to the first discharge outlet 41, and a position where it guides a sheet conveyed on the first sheet conveying path 3 from the sheet entrance 2 side, passes through the second branching section 32, and is switched back to the third sheet conveying 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 section 10.

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

[0028] The third discharge outlet 81 is located at the downstream end of the third sheet transport path 7 in the sheet transport direction. The third discharge roller pair 82 is arranged at the third discharge outlet 81. The third discharge tray 83 is located downstream of the third discharge outlet 81 in the sheet transport direction. A sheet that has been transported along the third sheet transport path 7 and reached the third discharge outlet 81 is passed through the third discharge outlet 81 by the third discharge roller pair 82 and discharged onto the third discharge tray 83. The third discharge tray 83 is one of the final discharge locations for sheets that have been post-processed by the sheet post-processing device 1.

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

[0030] The punching unit 91 is disposed on the first sheet transport path 3, immediately downstream of the sheet entrance 2. The punching unit 91 performs a punching process on the sheet transported on the first sheet transport path 3, to form punch holes.

[0031] The sheet binding unit 92 is disposed immediately upstream of the first sheet discharge section 4 in the sheet conveying direction of the first sheet conveying path 3. The sheet binding unit 92 staples (binds) a sheet bundle formed by stacking a plurality of sheets, and binds the sheet bundle. 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 stapling unit 92 in the sheet conveying direction of the first sheet conveying path 3. The sheet folding unit 100 folds a single sheet to form a crease. The sheet folding unit 100 can fold a single sheet in various ways, such as in half, Z-fold, outward three-fold, and inward three-fold.

[0033] The binding section 94 is disposed immediately upstream of the third sheet discharge section 8 in the sheet conveying direction of the third sheet conveying path 7. The binding section 94 has a center folding section 941 and a saddle stitching section 942. The binding section 94 performs center folding and saddle stitching on a sheet bundle formed by stacking a plurality of sheets, in which the sheets are folded and stitched at approximately the center in the sheet conveying direction, to form a booklet.

[0034] The post-processing control unit (control unit) 10 includes a CPU, a memory unit, and other electronic circuits and electronic components (none of which are 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 commands from the main body control unit 203 and, using the CPU, controls the operation of each component provided in the sheet post-processing device 1 based on control programs and data stored in the memory unit to perform processing related to the functions of the sheet post-processing device 1. The first sheet transport path 3, the first sheet discharge unit 4, the second sheet transport path 5, the second sheet discharge unit 6, the third sheet transport path 7, the third sheet discharge unit 8, and the post-processing unit 9 each receive individual commands from the post-processing control unit 10 and perform post-processing on sheets in cooperation with each other. The function of the post-processing control unit 10 may also be performed by the main body control unit 203 of the image forming apparatus 200.

[0035] [3. Configuration of the first sheet discharge section] Next, the configuration around the first sheet discharge section 4 will be described. Fig. 3 is a perspective view of the periphery of the first sheet discharge section 4. As shown in Fig. 3, the first sheet discharge section 4 (sheet discharge device) includes the first discharge opening 41, the first discharge roller pair 42, the first discharge tray 43, and in addition, an air blowing mechanism 44. The air blowing mechanism 44 includes an air blower 45, an air blower duct 46, and an air outlet 47.

[0036] The pair of blowers 45 are disposed above the first discharge port 41, on both sides in the sheet width direction (arrow BB' direction) perpendicular to the sheet discharge direction (arrow A direction). In this embodiment, a sirocco fan is used as the blower 45.

[0037] A pair of air ducts 46 are arranged on both sides in the sheet width direction and extend in the sheet discharge direction. One end of each air duct 46 (the upstream end in the sheet discharge direction) is connected to the outlet of the corresponding air blower device 45. The other end of each air duct 46 (the downstream end in the sheet discharge direction) is formed with an air outlet 47. Each air outlet 47 opens downward above the first outlet 41.

[0038] 4 is a side cross-sectional view of the periphery of the first sheet discharge section 4. As shown in Fig. 4, a sheet binding unit 92 is disposed upstream (to the right in Fig. 4) of the first sheet discharge section 4 in the sheet discharge direction (the direction of arrow A). The sheet binding unit 92 includes a processing tray 521, a staple section 71, and a reference plate 73.

[0039] The processing tray 521 is a rectangular tray extending in the sheet discharge direction (the direction of arrow A) and the sheet width direction (the direction of arrow BB'). A plurality of sheets (a stack of sheets) to be stapled is stacked on the processing tray 521. The sheets S are carried into the processing tray 521 in the same direction as the discharge direction (the carry-in direction, the direction of arrow A) by a carry-in roller pair 54. The stapled sheet stack is sent in the sheet discharge direction by a first discharge roller pair 42 and discharged onto a first discharge tray 43.

[0040] The processing tray 521 includes width restriction members 523. A pair of width restriction members 523 are arranged in the sheet width direction. The width restriction members 523 are reciprocally movable in the sheet width direction along the upper surface of the processing tray 521 via a drive mechanism (not shown) such as a rack and pinion gear. In this embodiment, every time a sheet S is carried into the processing tray 521, the width restriction members 523 are reciprocally moved by the drive mechanism. As a result, the position in the sheet width direction of the sheet S carried into the processing tray 521 is aligned.

[0041] The stapler 71 is disposed facing the edge of the sheet S on the downstream side (right side in FIG. 4 ) in the alignment direction (arrow A′ direction), which is the opposite direction to the conveying direction of the sheets S. The stapler 71 is movable in the sheet width direction (arrow BB′ direction) along the edge of the sheets by the driving force of a motor (not shown), and staples the stack of sheets S.

[0042] The reference plate 73 is fixed to the processing tray 521 so as to face the end of the processing tray 521 on the downstream side in the alignment direction (the right side in FIG. 4). The reference plate 73 has a generally U-shape in a cross section perpendicular to the sheet width direction, with the upstream side in the alignment direction (the left side in FIG. 4) being open. The reference plate 73 abuts against the edge of a sheet being carried into the processing tray 521, and aligns the sheet in the carry-in direction (the direction of arrow A').

[0043] A pair of input rollers 54 is disposed above the processing tray 521. A sheet detection sensor 48 is disposed near the pair of input rollers 54. The sheet detection sensor 48 detects the timing when the sheet S passes through the pair of input rollers 54. As the sheet detection sensor 48, for example, a PI (photointerrupter) sensor having a detection unit made up of a light emitting unit and a light receiving unit is used.

[0044] A hitting member 53 and an alignment member 55 are provided downstream (on the left side in FIG. 4) of the pair of carry-in rollers 54 in the carry-in direction of the sheet S. The hitting member 53 is supported so as to be able to swing along the carry-in direction of the sheet S. The hitting member 53 swings downward when the trailing end of the sheet S passes the pair of carry-in rollers 54, thereby hitting the sheet S downward and aligning it with the processing tray 521.

[0045] The alignment members 55 are arranged at multiple locations (four locations in this embodiment) along the sheet width direction (direction perpendicular to the paper surface of FIG. 4). The alignment members 55 assist in aligning the sheets S by moving (switching back) the sheets S carried onto the processing tray 521 in an alignment direction approaching the reference plate 73. The alignment members 55 include a paddle holder 56 and an alignment paddle 57.

[0046] The paddle holder 56 is supported at the lower end of the transport frame 53 so as to be swingable along the carry-in direction of the sheet S. A rotational drive force is input to the swing shaft of the paddle holder 56 by a paddle drive motor (not shown). A rotational drive force in a direction (counterclockwise in FIG. 4) that sends the sheet S in the alignment direction is input to the alignment paddle 57 by a drive source (not shown) such as a motor. The alignment paddle 57 rotates while abutting against the upper surface of the sheet being carried into the processing tray 521, thereby moving the sheet S in the alignment direction and abutting the edge of the sheet S against the reference plate 73 to align it.

[0047] The swinging of the paddle holder 56 is controlled based on the detection timing of the sheet detection sensor 48. Specifically, the paddle holder 56 is swung upward at the timing when the sheet detection sensor 48 detects that the leading edge of the sheet S has passed through the pair of carry-in rollers 54. As a result, the alignment paddle 57 moves away from the upper surface of the processing tray 521 (or the sheets S stacked on the processing tray 521).

[0048] 4 shows a state immediately before a new sheet S is carried onto the processing tray 521, in which the paddle holder 56 swings upward (clockwise), and the alignment paddle 57 is disposed at a position (reference position) spaced apart from the processing tray 521. In addition, the nip between the lower discharge roller 421 and the upper discharge roller 422 that make up 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 passes through the discharge roller pair 42 and protrudes onto the first discharge tray 43.

[0049] Then, the trailing edge of a new sheet S carried onto the processing tray 521 is struck by the striking member 53 to align it with the processing tray 521, and then the paddle holder 56 is swung a predetermined amount in the opposite direction (counterclockwise). As a result, the alignment paddle 57 is positioned (acting position) so as to contact the upper surface of the sheet S. By rotating the alignment paddle 57 in this state, the sheet S is pulled in the alignment direction (arrow A' direction) along the processing tray 521. By repeating the above operation every time a sheet S is carried into the processing tray 521, it is possible to prevent interference between the leading edge of the sheet S carried onto the processing tray 521 and the alignment paddle 57, while ensuring that the alignment paddle 57 comes into contact with the upper surface of the sheet.

[0050] 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, aligned in the carry-in direction by the reference plate 73, and stacked.

[0051] Then, after the staple unit 71 moves to the predetermined stapling position, the post-processing control unit 10 sends a control signal to the staple unit 71 to staple the plurality of sheets S aligned by the reference plate 73. The post-processing control unit 10 brings the first discharge roller pair 42 into contact (forms a nip) and rotates the first discharge roller pair 42 in the discharge direction. As a result, the stack of sheets S that has been stapled is discharged onto the first discharge tray 43 by the first discharge roller pair 42.

[0052] [5. Sheet discharge assist operation to the first discharge tray by the air blower mechanism] Next, the sheet discharge assist operation by the air blowing mechanism 44 onto the first discharge tray 43 will be described. Fig. 5 is a perspective view from above showing the state in which the sheet S is discharged onto the first sheet discharge section 4. When the sheet S that will not be subjected to post-processing is discharged onto the first discharge tray 43, the air blowing mechanism 44 blows air from above toward both widthwise ends of the sheet S, thereby suppressing any upward curl that occurs at both widthwise ends of the sheet S.

[0053] 5, the first sheet discharge section 4 has a duct movement mechanism 60 and a duct movement motor 61 connected to the duct movement mechanism 60. The duct movement mechanism 60 moves the pair of air ducts 46 in the sheet width direction. In this embodiment, a rack and pinion mechanism is used as the duct movement mechanism 60.

[0054] More specifically, the duct movement mechanism 60 includes a pinion gear and a pair of racks (neither of which is shown) fixed to each of the pair of air ducts 46. The rotational driving force of a duct movement motor 61 is input to the pinion gear. Each of the pair of racks extends along the seat width direction, and has rack teeth formed thereon that mesh with the pinion gear from the opposite side of the rotation center.

[0055] By rotating the pinion gear in a predetermined direction using the duct movement motor 61, the air blower duct 46 is moved symmetrically with the air blower 45 relative to the center of the seat width direction. For example, by rotating the pinion gear in the forward direction, the air blower 45 and the air blower duct 46 are moved outward in the seat width direction. On the other hand, by rotating the pinion gear in the reverse direction, the air blower 45 and the air blower duct 46 are moved inward in the seat width direction.

[0056] 5 shows a case where a large-sized sheet S1 is discharged onto the first discharge tray 43. In this case, the air blower 45 and the air duct 46 are disposed at positions facing both widthwise ends of the sheet S1. As indicated by the white arrows in FIG. 5, the airflow generated by the air blower 45 passes through the air duct 46 and is blown downward from the air outlet 47 toward an area that is more inward in the widthwise direction than the side edge of the sheet S1 discharged onto the first discharge tray 43.

[0057] 6 shows a case where a small-sized sheet S2 is discharged onto the first discharge tray 43. In this case, the air blower 45 and the air duct 46 are moved inward in the sheet width direction from the positions shown in FIG. 5 and are positioned opposite both widthwise ends of the sheet S2. As shown by the white arrows in FIG. 6, the airflow generated by the air blower 45 passes through the air duct 46 and is blown downward from the air outlet 47 toward an area that is more inward in the width direction than the side edge of the sheet S2 discharged onto the first discharge tray 43.

[0058] According to the above configuration, the position at which the air is blown by the air blowing mechanism 44 onto the first discharge tray 43 can be changed by moving the air blowing device 45 and the air blowing duct 46 in the sheet width direction in accordance with the width size of the sheet S discharged onto the first discharge tray 43. Therefore, regardless of the width size of the sheet S, it is possible to suppress upward curl that occurs at both widthwise ends of the sheet S. As a result, it is possible to improve the alignment of the sheet S discharged onto the first discharge tray 43.

[0059] 7 is a perspective view from above showing a state in which a small-sized sheet S2 is discharged into the first sheet discharge section 4 according to the second embodiment of the present invention. In this embodiment, the air supply duct 46 is swingable about swing axes O1 and O2 that are parallel to the sheet discharge direction (the direction of arrow A). In addition, a duct swing motor 62 is provided instead of the duct movement mechanism 60 and duct movement motor 61 of the first embodiment.

[0060] 7 shows a state in which a small-sized sheet S2 is discharged onto the first discharge tray 43. In this case, the air ducts 46 are swung from the state shown in FIG. 5 so that the air outlets 47 face inward in the sheet width direction. As a result, as shown by the white arrows in FIG. 7, the airflow generated by the air blower 45 passes through the air ducts 46 and is blown downward from the air outlets 47 toward an area that is more inward in the width direction than the side edge of the sheet S2 discharged onto the first discharge tray 43.

[0061] When a large-sized sheet S1 is discharged onto the first discharge tray 43, the air ducts 46 are swung from the state shown in Fig. 7 so that the air outlets 47 face outward in the sheet width direction, resulting in the state shown in Fig. 5. As a result, as shown by the white arrows in Fig. 5, the air flow generated by the air blower 45 passes through the air duct 46 and is blown downward from the air outlets 47 toward an area that is more inward in the width direction than the side edge of the sheet S1 discharged onto the first discharge tray 43.

[0062] According to the above configuration, the position at which the air is blown onto the first discharge tray 43 by the air blowing mechanism 44 can be changed by swinging the air blower duct 46 to change the angle of the air blowing port 47 in accordance with the width size of the sheet S discharged onto the first discharge tray 43. This makes it possible to suppress upward curls that occur at both widthwise ends of the sheet S, similar to the first embodiment, regardless of the widthwise size of the sheet S. As a result, it is possible to improve the alignment of the sheet S discharged onto the first discharge tray 43.

[0063] Furthermore, since the air blowing position of the air blowing mechanism 44 can be changed simply by swinging the air blower duct 46, there is no need to ensure movement space for the duct movement mechanism 60 and the air blower duct 46, as in the first embodiment. Therefore, the number of parts can be reduced compared to the first embodiment, and a compact configuration can be achieved.

[0064] In the first and second embodiments described above, it is preferable that the blowing mechanism 44 stops blowing air until the leading edge of the sheet S discharged by the first discharge roller pair 42 contacts the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43), and that the blowing mechanism 44 starts blowing air after the leading edge of the sheet S contacts the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43).

[0065] Specifically, when the sheet detection sensor 48 (see FIG. 4) transmits a detection signal indicating the timing of detecting the leading edge of the sheet S, the post-processing control unit 10 determines whether a predetermined time T has elapsed since the detection timing. When the predetermined time T has elapsed, the post-processing control unit 10 determines that the leading edge of the sheet S has come into contact with the first discharge tray 43 (or the sheets S stacked on the first discharge tray 43), and transmits a control signal to the air blowing device 45 to start blowing air. The predetermined time T is calculated based on the discharge speed of the sheet S.

[0066] By starting the air blowing at the above timing, it is possible to suppress flapping of the leading edge of the sheet S in the discharge direction due to the air blowing, while intensively blowing the air flow to the trailing edge of the sheet S in the discharge direction, which is prone to curling. As a result, the sheet S can be stably discharged from the first discharge outlet 41, and can be stacked on the first discharge tray 43 while effectively suppressing curling of the trailing edge of the sheet S.

[0067] In addition to adjusting the air blowing position as described above, the flow rate of the airflow generated by the air blowing device 45 may be adjusted based on the widthwise size of the sheet S. Specifically, the post-processing control unit 10 increases the flow rate of the airflow generated by the air blowing device 45 as the widthwise size of the sheet S increases. This increases the flow rate of the airflow blown to a large-sized sheet S with a large curl, thereby more effectively suppressing the curl. The flow rate of the airflow can be adjusted by controlling the drive voltage applied to the air blowing device 45 using a control signal from the post-processing control unit 10.

[0068] Fig. 8 is a flowchart showing an example of adjustment control of the air blowing position by the air blowing mechanism 44 in the first sheet discharge section 4 of this embodiment. The procedure for adjusting the air blowing position will be described along the steps of Fig. 8, with reference to Figs. 1 to 7 as necessary. Note that in the initial state, the air blowing position to the first discharge tray 43 by the air blowing mechanism 44 is set to the air blowing position (hereinafter referred to as the reference position) corresponding to the most frequently used size of sheet S (for example, A4 landscape size).

[0069] When a discharge process command for the sheet S is input from the main body control unit 203 of the image forming apparatus 200 to the first sheet discharge unit 4, the size of the sheet S is input along with the discharge process command (step S1). The size of the sheet S is input from the operation panel 202 of the image forming apparatus 200. For example, the manufacturer, product name, model number, etc. of the sheet S may be associated with size information of the corresponding sheet S and stored in advance in the main body control unit 203. In this way, the main body control unit 203 can recognize the size of the sheet S to be used simply by the user selecting the manufacturer, product name, model number, etc. of the sheet S from the operation panel 202.

[0070] The post-processing control unit 10 determines whether or not it is necessary to adjust the position at which the air is blown onto the first discharge tray 43 by the air blowing mechanism 44 based on the input size of the sheet S (step S2). If it is determined that it is necessary to adjust the air blowing position (Yes in step S2), the post-processing control unit 10 adjusts the air blowing position onto the first discharge tray 43 from the reference position (step S3).

[0071] For example, in the first sheet discharge section 4 of the first embodiment, the duct movement motor 61 is driven to move the air blower 45 and the air duct 46 along the sheet width direction. Specifically, when the width of the sheet S is larger than the A4 landscape size, the air blower 45 and the air duct 46 are moved outward in the sheet width direction, so that the air blowing position is more outward in the width direction than the reference position. On the other hand, when the width of the sheet S is smaller than the A4 landscape size, the air blower 45 and the air duct 46 are moved inward in the sheet width direction, so that the air blowing position is more inward in the width direction than the reference position.

[0072] Furthermore, in the first sheet discharge section 4 of the second embodiment, the duct swing motor 62 is driven to swing the air duct 46. Specifically, when the width of the sheet S is larger than the A4 landscape size, the air duct 46 is swung so that the air outlet 47 faces outward in the sheet width direction, and the air blowing position is located widthwise outside of the reference position. When the width of the sheet S is smaller than the A4 landscape size, the air duct 46 is swung so that the air outlet 47 faces inward in the sheet width direction, and the air blowing position is located widthwise inside of the reference position.

[0073] The adjustment amount (movement amount, swing angle) from the reference position is determined based on a correction table that defines the relationship between the size of the sheet S and the corresponding air blowing position. If it is determined that adjustment of the air blowing position is not necessary (No in step S2), the post-processing control unit 10 proceeds to the next step without changing the air blowing position from the reference position.

[0074] Next, the post-processing control unit 10 starts discharging the sheets S onto the first discharge tray 43 (step S4), and counts the number of discharged sheets S based on the detection result of the sheet detection sensor 48 (step S5). Then, the post-processing control unit 10 starts blowing air by the blower mechanism 44 (step S6). More specifically, the post-processing control unit 10 switches the blower device 45 from the off state to the on state after the leading edge of the sheet S discharged by the first discharge roller pair 42 comes into contact with the first discharge tray 43 (or the sheets S stacked on the first discharge tray 43).

[0075] Next, the post-processing control unit 10 stops the air blowing by the air blowing mechanism 44 (step S7). More specifically, the post-processing control unit 10 switches the air blowing device 45 from the on state to the off state at the timing when the rear end of the sheet S discharged by the first discharge roller pair 42 comes into contact with the first discharge tray 43 (or the sheets S stacked on the first discharge tray 43).

[0076] Next, the post-processing control unit 10 determines whether or not a predetermined number of sheets S have been discharged onto the processing tray 521 (step S8). If the predetermined number of sheets S have not been discharged (No in step S8), the process returns to step S4, and the process continues to discharge new sheets S, count the number of discharged sheets, and start and stop blowing air by the blower mechanism 44 (steps S4 to S7).

[0077] If the predetermined number of sheets S have been transported (Yes in step S8), the post-processing control unit 10 sends a control signal to the duct drive motor 61 (or the duct swing motor 62) to return the air blowing position to the reference position (step S9), and ends the process.

[0078] 8, the air blowing position of the air blowing mechanism 44 is adjusted to an optimal position based on the widthwise size of the sheet S. Therefore, regardless of the size of the sheet S, the curls at both widthwise ends of the sheet S can be suppressed by the air flow, and the ease of stacking and discharging the sheet S onto the first discharge tray 43 can be ensured.

[0079] In particular, when the image forming apparatus 200 connected to the sheet post-processing device 1 is an inkjet recording apparatus as in this embodiment, the discharged sheets S tend to curl significantly, but even in such cases, the sheets S can be discharged and stacked stably.

[0080] Although the embodiments of the present invention have been described above, 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 each of the above embodiments, the post-processing control unit 10 automatically adjusts the air blowing position of the air blowing mechanism 44 based on size information of the sheet S. However, the user may be able to adjust the air blowing position of the air blowing mechanism 44 at any timing. For example, it is conceivable that an air blowing position adjustment mode for switching the air blowing position of the air blowing mechanism 44 is provided on the operation panel 202, and the user may be able to select the mode depending on the size of the sheet discharged to the first discharge tray 43.

[0081] Furthermore, in each of the above embodiments, the size information of the sheet S is input from the operation panel 202 of the image forming apparatus 200, but the size information of the sheet S may also be acquired automatically. For example, the size of the sheet S conveyed from the image forming apparatus 200 to the sheet post-processing apparatus 1 can be detected by a sheet size detection sensor disposed at any position on the sheet transport path from the image forming apparatus 200 to the sheet post-processing apparatus 1. As the sheet size detection sensor, for example, a PI (photointerrupter) sensor having a detection unit consisting of a light-emitting element and a light-receiving element is used.

[0082] In addition, in each of the above embodiments, the blower device 45 and the air outlet 47 are connected via the air duct 46, but the blower device 45 and the air outlet 47 may be directly connected without providing the air duct 46.

[0083] Furthermore, in the above-described embodiments, the first sheet discharge section 4 is exemplified as the sheet discharge device of the present invention, but the present invention is not limited to this and may be applied to the second sheet discharge section 6.

[0084] Furthermore, in the above embodiment, an inkjet recording device is exemplified as the image forming apparatus 200, but an electrophotographic printer or copier can also be used as the image forming apparatus 200. Note that in the inkjet recording method in which ink is ejected onto a sheet, curling of the sheet is more likely to occur than in the electrophotographic method. For this reason, the present invention is particularly useful for a sheet post-processing device 1 to which an inkjet recording device is connected as the image forming apparatus 200.

[0085] In addition, in the above embodiment, the first sheet discharge section 4 of the sheet post-processing device 1 connected to the image forming device 200 is exemplified as the sheet discharge device of the present invention, but the sheet discharge device of the present invention can also be applied to the sheet discharge section of the image forming device 200 that is used without being connected to the sheet post-processing device 1. [Industrial Applicability]

[0086] The present invention can be used in a sheet discharge device that discharges sheets, and a sheet post-processing device and an image forming apparatus that include the same. [Explanation of symbols]

[0087] 1 Sheet post-processing device 2 Sheet entrance 3 First sheet transport path 4. First sheet discharge section (sheet discharge device) 10 Post-processing control unit (control unit) 41 1st discharge port (sheet discharge port) 42 First discharge roller pair (discharge member) 43 First output tray (sheet output tray) 44 Blower mechanism 45 Blower 46 Ventilation duct 47 Ventilation vent 48 Sheet detection sensor 521 Processing Tray 55 Alignment member 60 Duct moving mechanism (moving mechanism) 61 Duct movement motor (movement mechanism) 62 Duct swing motor (swing mechanism) 71 Staple section 92 Sheet binding unit 200 Image forming device S, S1, S2 seats

Claims

1. a sheet discharge port through which the sheet is discharged; a discharge member disposed at the sheet discharge port and configured to transport the sheet in a discharge direction; a sheet discharge tray disposed downstream of the sheet discharge outlet in the discharge direction, on which the sheets discharged from the sheet discharge outlet are stacked; a blowing mechanism that blows airflow onto the sheet discharged from the sheet discharge port; In a sheet ejection device comprising: The blower mechanism includes: a pair of air outlets that blow airflows from above onto both ends of the sheet in a width direction perpendicular to the sheet discharge direction discharged from the sheet discharge outlet; a blower connected to the air outlet and configured to generate the airflow; and A sheet ejection device, characterized in that the blowing position of the air flow relative to the sheet can be adjusted according to the size of the sheet in the width direction.

2. a moving mechanism that reciprocates the air outlet along the width direction, The sheet ejection device according to claim 1 , wherein the air blowing position is adjusted by moving the air blowing port along the width direction using the movement mechanism.

3. an input unit for inputting the size of the sheet; a control unit that controls the air blowing mechanism and the movement mechanism; Equipped with The sheet ejection device according to claim 2, characterized in that the control unit adjusts the air blowing position by moving the air outlet along the width direction based on the width direction size of the sheet inputted to the input unit.

4. a swing mechanism that swings the air outlet about a swing axis parallel to the exhaust direction, 2. The sheet ejection device according to claim 1, wherein the air blowing position is adjusted by changing the angle of the air blowing port using the swing mechanism.

5. an input unit for inputting the size of the sheet; a control unit that controls the blowing mechanism and the swinging mechanism; Equipped with The sheet ejection device according to claim 4 , wherein the control unit adjusts the air blowing position by changing the angle of the air blowing port based on the width direction size of the sheet inputted to the input unit.

6. 6. The sheet ejection device according to claim 3, wherein the control unit is capable of adjusting the flow rate of the air flow generated by the blower device based on the width direction size of the sheet inputted to the input unit.

7. The control unit The sheet ejection device according to claim 3 or claim 5, characterized in that the blower device starts blowing the air flow after the leading edge of the sheet comes into contact with the sheet ejection tray or the sheets stacked on the sheet ejection tray.

8. a post-processing unit that performs predetermined post-processing on the sheet; a sheet ejection device according to any one of claims 1 to 5, which ejects the sheet that has been subjected to post-processing by the post-processing section; A sheet post-processing device comprising:

9. an image forming device that forms an image on a sheet; a sheet post-processing device according to claim 8, which performs a predetermined post-processing on the sheet on which an image has been formed by the image forming device; An image forming system comprising:

10. 10. The image forming system according to claim 9, wherein the image forming apparatus is an inkjet recording apparatus that discharges ink onto the sheet to record an image.

11. an image forming unit that forms an image on a sheet; a sheet ejection device according to any one of claims 1 to 5, which ejects the sheet on which an image has been formed by the image forming unit; An image forming apparatus comprising:

12. 12. The image forming apparatus according to claim 11, wherein the image forming unit ejects ink onto the sheet to record an image.

Images