Sheet discharge device, and sheet post-processing device and image forming apparatus equipped with the same

Abstract

To provide a sheet discharge device capable of effectively improving a dischargeability of a sheet whose both widthwise ends are curled, and a sheet post-processing device and an image forming apparatus equipped with the same.SOLUTION: A sheet discharge device includes a sheet discharge outlet, a discharge member, a sheet discharge tray, and a blower mechanism. The discharge member is disposed at the sheet discharge outlet and transports the sheet in a discharge direction. The sheet discharge tray is disposed downstream of the sheet discharge outlet in the discharge direction, and receives the sheet discharged from the sheet discharge outlet. The air blower mechanism has an air blowing outlet that blows an airflow from above onto the sheet discharged from the sheet discharge outlet, and an air blowing device that is connected to the air blowing outlet and generates an airflow. At least a pair of air blowing outlets are provided above the sheet discharge outlet, and disposed in a center of a width direction perpendicular to the sheet discharge direction, and the airflow from the air blowing outlets is blown obliquely downward from inside to outside in a width direction of the sheet.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] An image forming apparatus such as a copying machine or a printer, and a sheet post-processing apparatus that performs post-processing on a sheet include a sheet discharging device having a pair of discharging rollers and a discharging tray. A sheet (paper) after image formation by the image forming apparatus is discharged onto the discharging tray by the sheet discharging device provided in the image forming apparatus. Alternatively, after being carried into the sheet post-processing apparatus and subjected to predetermined post-processing, the sheet is discharged onto the discharging tray by the sheet discharging device provided in the sheet post-processing apparatus.

[0003] In such a sheet discharging device, when discharging a sheet with a large curl, the curled sheet may block the sheet discharge port as it is, and there is a risk of poor sheet discharge. Therefore, a method of stabilizing the sheet discharge by blowing air from above the sheet discharge port by a fan has been adopted.

[0004] Patent Document 1 discloses a recording medium discharging device having a discharging means for discharging a recording medium from inside the apparatus, a placing means for placing the recording medium discharged from the discharging means, and a blowing means for blowing air in a direction parallel to the discharging direction of the recording medium on the upper surface side of the recording medium discharged from the discharging means, which reduces the air pressure on the upper surface of the recording medium by blowing air and improves the discharging quality.

[0005] Patent Document 2 discloses a sheet conveying device including a processing tray for stacking sheets discharged from a conveying mechanism at a position on the first surface side of the sheet, a blowing unit for blowing air toward the second surface of the sheet discharged from the conveying mechanism to guide the sheet to the second surface side, a post-processing mechanism for performing post-processing on the stack of sheets stacked on the processing tray, a discharging mechanism for discharging the stack of sheets after post-processing from the processing tray, and a stacking tray for stacking the stack of sheets discharged by the discharging mechanism.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Document 1, for the purpose of improving the dischargeability of a sheet with a curled tip, the configuration is to blow air in a direction parallel to the discharge direction of the sheet on the upper surface side of the sheet. Further, in Patent Document 2, for the purpose of improving the stackability of the sheet on the processing tray, the configuration is to blow air at the center in the width direction of the sheet. Therefore, it has been difficult to stably discharge a sheet with curled both ends in the width direction in both cases.

[0008] In view of the above problems, an object of the present invention is to provide a sheet discharging device capable of effectively improving the dischargeability of a sheet with curled both ends in the width direction, a sheet post-processing device including the same, and an image forming apparatus.

Means for Solving the Problems

[0009] In order to achieve the above object, a first configuration of the present invention is a sheet discharging device including a sheet discharge port, a discharge member, a sheet discharge tray, and a blower mechanism. The sheet discharge port discharges the sheet. The discharge member is disposed at the sheet discharge port and conveys the sheet in the discharge direction. The sheet discharge tray is disposed on the downstream side of the sheet discharge port with respect to the discharge direction, and the sheet discharged from the sheet discharge port is stacked thereon. The blower mechanism blows an air flow onto the sheet discharged from the sheet discharge port. The blower mechanism has a blower port that blows an air flow onto the sheet discharged from the sheet discharge port from above, and a blower device that is connected to the blower port and generates the air flow. The blower port is provided above the sheet discharge port, and at least a pair of them are arranged at the central portion in the width direction orthogonal to the discharge direction of the sheet. The air flow from the blower port is blown obliquely downward from the inner side to the outer side in the width direction of the sheet.

Advantages of the Invention

[0010] According to the first configuration of the present invention, an air flow is blown obliquely downward from the inner side to the outer side in the width direction of the sheet from a pair of blower ports provided at the central portion in the width direction of the sheet. Thereby, the curls at both ends in the width direction of the sheet discharged onto the discharge tray can be suppressed by the air flow, and the loadability and dischargeability of the sheet onto the sheet discharge tray can be improved.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0012] [1. Configuration of Image Forming System] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of an image forming system including a sheet post-processing apparatus 1 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 controls the overall operation of the image forming apparatus 200 and controls each part of the image forming apparatus 200.

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

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

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

[0018] The first sheet conveyance path 3 extends in a substantially horizontal direction in a direction away from the image forming device 200 (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 of the first sheet conveyance path 3 in the sheet conveyance direction. The first sheet conveyance path 3 has a plurality of conveyance roller pairs 3r and conveys the sheet carried into the sheet post-processing device 1 from the sheet inlet 2 toward the downstream side in the sheet conveyance direction.

[0019] The first sheet discharge 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 discharge port 41 is located at the downstream end in the sheet conveyance direction of the first sheet conveyance path 3. The first discharge roller pair 42 is disposed at the first discharge port 41. The first discharge tray 43 is located on the downstream side in the sheet conveyance direction of the first discharge port 41. The sheet conveyed through the first sheet conveyance path 3 and reaching the first discharge port 41 is discharged onto the first discharge tray 43 through the first discharge port 41 by the first discharge roller pair 42. The first discharge tray 43 is one of the final discharge locations for the sheets that have been post-processed by the sheet post-processing apparatus 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 unit 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 unit 6 is referred to as the sheet conveyance direction in the second sheet conveyance path 5. The first branch portion 31 is located at the upstream end in the sheet conveyance direction of the second sheet conveyance path 5. The second sheet conveyance path 5 has a plurality of conveyance roller pairs 5r, and branches the sheet conveyed through the first sheet conveyance path 3 at the first branch portion 31 and conveys it toward the second sheet discharge unit 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 to the first discharge port 41 along the first sheet conveyance path 3 and a position that branches off 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 the folding process and passed through the second folding conveyance path 106 described later to the second sheet conveyance path 5. The first switching guide 311 is connected to a drive mechanism (not shown), and its operation is controlled by the post-processing control unit 10.

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

[0024] The second 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 conveyed through the second sheet conveyance path 5 and reaching 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 branches from the second branch portion 32 on the first sheet conveyance path 3 and extends downward to the third sheet discharge portion 8. The direction from the second branch portion 32 toward the third sheet discharge portion 8 is referred to as the sheet conveyance direction in the third sheet conveyance path 7. The second branch portion 32 is located on the downstream side of the first branch portion 31 with respect to the sheet conveyance direction of the first sheet conveyance path 3 and at the upstream end of the third sheet conveyance path 7 in the sheet conveyance direction. The third sheet conveyance path 7 has a plurality of conveyance roller pairs 7r, and branches the sheet conveyed on the first sheet conveyance path 3 at the second branch portion 32 and conveys it toward the third sheet discharge portion 8.

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

[0027] The third sheet discharge 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 of the third sheet conveyance path 7 in the sheet conveyance direction. The third discharge roller pair 82 is disposed at the third discharge port 81. The third discharge tray 83 is located on the downstream side of the third discharge port 81 in the sheet conveyance direction. The sheet conveyed 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 sheet that has been post-processed by the sheet post-processing apparatus 1.

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

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

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

[0032] The sheet folding unit 100 is disposed 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 a folding process on a single sheet to form a fold. The sheet folding unit 100 can perform a folding process such as double folding, Z folding, outside triple folding, inside triple folding, etc. on a single sheet.

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

[0034] The post-processing control unit (control unit) 10 includes a CPU, a storage unit, and other electronic circuits and 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 program and data for control 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 discharge unit 4, the second sheet conveyance path 5, the second sheet discharge unit 6, the third sheet conveyance path 7, the third sheet discharge unit 8, and the post-processing unit 9 receives an individual command from the post-processing control unit 10 and performs post-processing on the sheet in conjunction with each other. Note that the functions of the post-processing control unit 10 may be shared by the main body control unit 203 of the image forming apparatus 200.

[0035] [3. Configuration of the First Sheet Discharge Unit] Next, the configuration around the first sheet discharge unit 4 will be described. FIG. 3 is a perspective view of the area around the first sheet discharge unit 4. FIG. 4 is a side cross-sectional view of the area around the first sheet discharge unit 4. FIG. 5 is a plan view of the area around the first sheet discharge unit 4 as viewed from above. As shown in FIG. 3, the first sheet discharge unit 4 (sheet discharge device) includes, in addition to the first discharge port 41, the first discharge roller pair 42, and the first discharge tray 43, a blower mechanism 44. The blower mechanism 44 includes a blower device 45, a blower duct 46, and a blower port 47.

[0036] The blower device 45 is disposed above the first discharge port 41 and is arranged in a pair on the upstream side of the first discharge port 41 with respect to the sheet discharge direction (arrow A direction). In the present embodiment, a sirocco fan is used as the blower device 45.

[0037] The air supply duct 46 is connected to each of the pair of air supply devices 45. The pair of air supply ducts 46 each extend in the sheet discharge direction toward the upper part of the first discharge port 41, and the tip is bent downward. One end of the air supply duct 46 (the end on the upstream side in the sheet discharge direction) is connected to the outlet of the air supply device 45. An air supply port 47 is formed at the other end of the air supply duct 46 (the end on the downstream side in the sheet discharge direction). The air supply port 47 is arranged inside the sheet width direction with respect to the minimum size of the sheet width discharged to the first discharge tray 43.

[0038] As shown in FIG. 4, a sheet binding unit 92 is arranged on the upstream side (the right side in FIG. 4) of the first sheet discharge unit 4 with respect to the sheet discharge direction (arrow A direction). The sheet binding unit 92 includes a processing tray 521, a stapling unit 71, and a reference plate 73.

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

[0040] The processing tray 521 includes a width restricting member 523. The width restricting members 523 are arranged in a pair in the sheet width direction. The width restricting member 523 is 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 a pinion gear. In the present embodiment, each time the sheet S is carried into the processing tray 521, the width restricting member 523 is reciprocally moved by the drive mechanism. As a result, the position of the sheet S carried into the processing tray 521 in the sheet width direction is aligned.

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

[0042] The reference plate 73 is fixed to the processing tray 521 so as to face the end portion on the downstream side (the right side in FIG. 4) in the alignment direction of the processing tray 521. The reference plate 73 has a substantially U-shaped cross section that is open on the upstream side in the alignment direction (the left side in FIG. 4) when viewed in a cross section orthogonal to the sheet width direction. The reference plate 73 abuts against the edge of the sheet carried into the processing tray 521 and aligns the sheet in the alignment direction (the direction of arrow A′).

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

[0044] A tapping member 53 and an aligning member 55 are provided on the downstream side (the left side in FIG. 4) of the pair of loading rollers 54 with respect to the feeding direction of the sheet S. The tapping member 53 is supported so as to be swingable along the feeding 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 to make it along the processing tray 521.

[0045] The aligning members 55 are arranged at a plurality of positions (four positions in the present embodiment) along the sheet width direction (the direction perpendicular to the plane of FIG. 4). The aligning members 55 move (switch back) the sheet S carried onto the processing tray 521 in the alignment direction approaching the reference plate 73 to assist in aligning the sheet S. The aligning members 55 include paddle holders 56 and aligning paddles 57.

[0046] The paddle holder 56 is supported at the lower end of the conveyance frame 53 so as to be swingable along the sheet S loading direction. A rotational driving force is input to the swing axis of the paddle holder 56 by a paddle drive motor (not shown). A rotational driving force in the direction of feeding out the sheet S in the alignment direction (counterclockwise direction in FIG. 4) is input to the alignment paddle 57 by a drive source such as a motor (not shown). By the alignment paddle 57 abutting against and rotating on the upper surface of the sheet 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.

[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 end of the sheet S has passed through the loading roller pair 54. As a result, the alignment paddle 57 is separated from the upper surface of the processing tray 521 (or the sheet S stacked on the processing tray 521).

[0048] FIG. 4 shows a state immediately before a new sheet S is carried onto the processing tray 521. The paddle holder 56 is swung upward (clockwise direction), and the alignment paddle 57 is disposed at a position separated from the processing tray 521 (reference position). Further, the nip between the lower discharge roller 421 and the upper discharge roller 422 constituting the first discharge roller pair 42 is released. Thereby, the sheet S carried from the loading roller pair 54 onto the processing tray 521 once passes through the discharge roller pair 42 and protrudes onto the first discharge tray 43.

[0049] Then, after tapping the rear end of the new sheet S carried onto the processing tray 521 with the tapping member 53 to align it along the processing tray 521, the paddle holder 56 is swung in the reverse direction (counterclockwise direction) by a predetermined amount. As a result, the alignment paddle 57 is disposed at a position (operating position) in contact with the upper surface of the sheet S. By rotating the alignment paddle 57 in this state, the sheet S is drawn in the alignment direction (arrow A' direction) along the processing tray 521. By repeating the above operation every time the sheet S is carried in, the alignment paddle 57 can be surely brought into contact with the upper surface of the sheet while avoiding interference between the leading end of the sheet S carried onto the processing tray 521 and the alignment paddle 57.

[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 restricting member 523, and aligned and stacked in the carrying direction by the reference plate 73.

[0051] When performing staple processing on the sheet S carried onto the processing tray 521, after the staple portion 71 has moved to a predetermined staple position, the post-processing control unit 10 transmits a control signal to the staple portion 71 and executes staple processing on a 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 (nip formation) and rotates the first discharge roller pair 42 in the discharge direction. Thereby, a bundle of sheets S subjected to staple processing is discharged to the first discharge tray 43 by the first discharge roller pair 42.

[0052] When performing sorting processing (shifting processing) on the sheet S carried onto the processing tray 521, the post-processing control unit 10 moves a pair of width restricting members 523 in the shifting direction of the sheet S every time a predetermined number of sheets S are carried onto the processing tray 521. Thereby, the sheets S are sorted and discharged to a plurality of positions on the first discharge tray 43. Further, the post-processing control unit 10 can also discharge the sheet S carried onto the processing tray 521 onto the first discharge tray 43 without performing staple processing and sorting processing.

[0053] [5. Sheet Discharge Assistance Operation to the First Discharge Tray by the Air Blowing Mechanism] Next, the sheet discharge assistance operation to the first discharge tray 43 by the air blowing mechanism 44 will be described. The sheet discharge assistance operation by the air blowing mechanism 44 is executed when sorting and discharging the sheet S to the first discharge tray 43, or when discharging the sheet S onto the first discharge tray 43 without performing staple processing and sorting processing on the sheet S. When discharging a bundle of sheets S that have been stapled onto the first discharge tray 43, there is no problem with the curling of the sheet S, so the sheet discharge assistance operation is unnecessary.

[0054] FIG. 6 is a front view of the state where the sheet S is discharged to the first sheet discharge unit 4 as viewed from the downstream side in the discharge direction. In FIG. 6, the description of the first discharge tray 43 is omitted. The air flow generated by the blower device 45 passes through the air duct 46 and is blown downward from the air outlet 47 toward the sheet S discharged to the first discharge tray 43.

[0055] More specifically, the air blowing mechanism 44 blows an air flow obliquely downward (in the direction of the white arrow in FIGS. 4 and 6) from the pair of air outlets 47 provided at the central portion in the width direction of the sheet S, from the inside to the outside in the width direction of the sheet S. The air blowing mechanism 44 blows the air flow onto a region outside the side edge in the width direction of the smallest-sized sheet S discharged from the first discharge port 41.

[0056] According to the above configuration, the curling at both ends in the width direction of the sheet S can be suppressed by the air flow, and the loadability and dischargeability of the sheet S onto the first discharge tray 43 can be ensured. In particular, when the image forming apparatus 200 connected to the sheet post-processing apparatus 1 is an inkjet recording apparatus as in the present embodiment, the curling of the discharged sheet S tends to be large, but even in such a case, the sheet S can be stably discharged and loaded.

[0057] If the blowing angle of the air flow from the air outlet 47 (the angle when the vertical direction is 0°) is too small, the air flow will not be sufficiently blown to both ends in the width direction of the large-sized sheet S1. On the other hand, if the blowing angle of the air flow from the air outlet 47 is too large, the air flow will be blown outside both ends in the width direction of the small-sized sheet S2. The blowing angle θ of the air flow from the air outlet 47 is preferably 15° to 20°.

[0058] Also, the blowing angle θ may be changed according to the size in the width direction of the sheet S. Specifically, the inclination of the air duct 46 can be made variable, and the user can manually adjust the inclination of the air duct 46 according to the size in the width direction of the sheet S. Alternatively, a drive mechanism for changing the inclination of the air duct 46 may be provided, and the post-processing control unit 10 may automatically adjust the inclination of the air duct 46 according to the size information of the sheet S input from the main body control unit 203 or the like. Thereby, regardless of the size in the width direction of the sheet S, the curls at both ends in the width direction can be effectively suppressed.

[0059] Also, in this embodiment, the blowing by the blower mechanism 44 is stopped until the leading end 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 the blowing by the blower mechanism 44 is started after the timing T1 when the leading end of the sheet S contacts the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43). The timing T1 is calculated based on the detection timing (detection signal) of the leading end of the sheet S transmitted from the sheet detection sensor 48 (see FIG. 4) and the discharge speed of the sheet S.

[0060] Specifically, when the post-processing control unit 10 receives the detection timing (detection signal) of the leading end of the sheet S from the sheet detection sensor 48 (see FIG. 4), it determines whether or not a predetermined time T has elapsed since the detection timing. Then, when the predetermined time T has elapsed, it determines that the leading end of the sheet S has contacted the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43), and transmits a control signal to the blower device 45 to start the blowing.

[0061] Then, the air blowing is stopped at the timing T2 when the rear end of the sheet S contacts the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43). The timing T2 is calculated based on the detection timing (detection signal) of the rear end of the sheet S transmitted from the sheet detection sensor 48 (see FIG. 4) and the discharge speed of the sheet S, similar to the timing T1.

[0062] By starting and stopping the air blowing at the above timing, it is possible to suppress the fluttering of the leading end in the discharge direction of the sheet S due to the air blowing, and to focus the air flow on the rear end in the discharge direction of the sheet S where curling is likely to occur. As a result, the sheet S can be stably discharged from the first discharge port 41 and stacked on the first discharge tray 43 while effectively suppressing the curling at both end portions in the width direction of the sheet S.

[0063] Also, when continuously discharging the sheet S from the first discharge port 41 to the first discharge tray 43, if the on and off of the air blowing device 45 are repeated at the above timing every time one sheet of the sheet S is discharged, a time lag occurs until the air flow reaches the target wind speed when the air blowing device 45 is switched from the off state to the on state. As a result, the wind speed of the air flow blown onto the sheet S becomes unstable, and the effect of suppressing curling becomes insufficient.

[0064] Therefore, when continuously discharging the sheet S from the first discharge port 41, the air blowing device 45 is driven at a reference speed (first speed) while the sheet S is being discharged, and after the sheet S is discharged, until the subsequent sheet S is discharged from the first discharge port 41 (between sheets), the air blowing device 45 is driven at a speed (second speed) slower than the reference speed.

[0065] By doing so, compared to the case where the on and off of the air blowing device 45 are repeated, the wind speed of the air blowing device 45 can be stably raised to the target wind speed. Also, since the wind speed is weakened between the discharge of the preceding sheet S and the discharge of the subsequent sheet S, the fluttering of the leading end in the discharge direction of the subsequent sheet S can also be suppressed.

[0066] FIG. 7 is a flowchart showing an example of drive control of the blower device 45 when discharging the sheet to the first sheet discharge unit 4 in the sheet post-processing apparatus 1 of the present embodiment. While referring to FIGS. 1 to 6 as necessary, the drive control of the blower device 45 when discharging the sheet S to the first sheet discharge unit 4 will be described along the steps of FIG. 7. In FIG. 7, a case where shift processing is performed on n sheets (n; natural number) of sheets S and discharged to the first discharge tray 43 will be described.

[0067] When a shift processing command for the sheet S is input from the main body control unit 203 (see FIG. 1) of the image forming apparatus 200, output information of the sheet S is input together with the shift processing command (step S1). The output information of the sheet S includes the size and the number of output sheets of the sheet S.

[0068] 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 to the processing tray 521 (step S2). Specifically, when the sheet detection sensor 93 detects that the rear end of the sheet S has passed through the carrying roller pair 54, the post-processing control unit 10 taps the rear end of the sheet S with the tapping member 53 to align it along the processing tray 521, and then the alignment paddle 57 moves to the operating position and the paddle portion 572 contacts the upper surface of the sheet S.

[0069] 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). At the same time, the shift processing by the width restricting member 523 (see FIG. 3) is also performed (step S3). Thereafter, the sheet S is further sent downstream in the alignment direction by the alignment paddle 57, and is aligned and stacked in the carrying direction by the reference plate 73.

[0070] Next, the post-processing control unit 10 brings the discharge lower roller 421 into contact with the discharge upper roller 422 (see FIG. 4) to form a nip of the first discharge roller pair 42, and rotates the first discharge roller pair 42 in the discharge direction. Thereby, the discharge of the m-th sheet S (1 ≦ m ≦ n) subjected to the shift process to the first discharge tray 43 (see FIG. 3) is started (step S4).

[0071] Next, the post-processing control unit 10 determines whether or not the timing T1 at which the leading end of the sheet S contacts the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43) has been reached (step S5). When the timing T1 is reached, the blower 45 is driven at full speed (step S6). Specifically, the post-processing control unit 10 sets the duty of the AC voltage applied to the blower 45 to 100%.

[0072] Next, the post-processing control unit 10 determines whether or not the timing T2 at which the trailing end of the sheet S contacts the first discharge tray 43 (or the sheet S stacked on the first discharge tray 43) has been reached (step S7). When the timing T2 is reached, the post-processing control unit 10 determines whether or not m + 1 ≦ n (step S8).

[0073] If m + 1 ≦ n (Yes in step S8), since the (m + 1)-th sheet S exists, after reaching the timing T2 described above, the blower 45 is driven at half speed (1 / 2 speed) (step S9). Specifically, the post-processing control unit 10 sets the duty of the AC voltage applied to the blower 45 to 50%. Then, the process returns to step S2, and the loading of the (m + 1)-th sheet S, the execution of the shift process, the discharge to the first discharge tray 43, the determination of whether or not the timing T1 has been reached, the full-speed driving of the blower 45, and the determination of whether or not the timing T2 has been reached are performed (steps S2 to S7).

[0074] On the other hand, if m + 1 > n in step S8 (No in step S8), since there is no (m + 1)-th sheet S (the sheet S discharged this time is the n-th sheet), after reaching the above-described timing T2, the driving of the blower 45 is stopped (step S10) and the process ends.

[0075] According to the control example shown in FIG. 7, when discharging the sheet S to the first sheet discharge unit 4, by blowing an air flow with the blower mechanism 4, curling at both end portions in the width direction of the sheet S can be suppressed and it can be stably stacked on the first discharge tray 43.

[0076] Also, when continuously discharging the sheets S, the blower 45 is driven at full speed (first speed) while the sheet S is being discharged, and the blower 45 is driven at half speed (second speed) during the period until the subsequent sheet S is discharged from the first discharge port 41 (between sheets). Thereby, the wind speed of the blower 45 can be stably increased to full speed in accordance with the discharge timing of the subsequent sheet S. Further, since the blower 45 is driven at half speed until the subsequent sheet S is discharged, fluttering at the leading end in the discharge direction of the subsequent sheet S can also be suppressed.

[0077] As described above, the embodiments of the present invention have been described, but 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, a pair of blower mechanisms 44 are arranged at the central portion in the sheet width direction, but as shown in FIG. 8, for example, two pairs of blower mechanisms 44 may be arranged at positions symmetric with respect to the central portion in the sheet width direction as the axis of symmetry.

[0078] If configured as shown in FIG. 8, the blower mechanism 44 to be used can be selected according to the size in the width direction of the sheet S stacked on the processing tray 521. Therefore, even when discharging sheets S with a large difference in size in the width direction, an air flow can be reliably blown onto both end portions in the width direction of the sheet S. The blower mechanisms 44 may be arranged in three or more pairs at positions symmetric with respect to the central portion in the sheet width direction as the axis of symmetry.

[0079] In the above-described embodiment, the blower duct 46 is used to connect the blower device 45 and the air outlet 47. However, the blower device 45 and the air outlet 47 may be directly connected without providing the blower duct 46.

[0080] In the above-described embodiment, as the sheet discharging device of the present invention, the first sheet discharging unit 4 in which the sheet S stacked on the processing tray 521 and subjected to the binding process by the sheet binding unit 92 is discharged is exemplified. However, the present invention is not limited to this, and it may be applied to the second sheet discharging unit 6.

[0081] In the above-described embodiment, an inkjet recording device is exemplified as the image forming device 200. However, an electrophotographic printer or a copying machine can also be used as the image forming device 200. In the inkjet recording method of discharging ink onto a sheet, the sheet is more likely to curl than in the electrophotographic method. Therefore, the present invention is particularly useful for the sheet post-processing device 1 to which an inkjet recording device is connected as the image forming device 200.

[0082] In the above-described embodiment, the first sheet discharging unit 4 of the sheet post-processing device 1 connected to the image forming device 200 is exemplified as the sheet discharging device of the present invention. However, the sheet discharging device of the present invention can also be applied to the sheet discharging unit of the image forming device 200 that is used without being connected to the sheet post-processing device 1.

Industrial Applicability

[0083] The present invention can be used for a sheet discharging device that discharges sheets, a sheet post-processing device including the same, and an image forming device.

Explanation of Reference Numerals

[0084] 1 Sheet post-processing device 2 Sheet inlet 3 First sheet conveyance path 4 First sheet discharging unit (sheet discharging device) 10 Post-processing control unit (control unit) 41 First discharge port (discharge port) 42 First discharge roller pair (discharge member) 43 First discharge tray (sheet discharge tray) 44 Blower mechanism 45 Blower device 46 Blower duct 47 Air outlet 521 Processing tray 55 Alignment member 71 Staple part 92 Sheet binding unit 93 Sheet detection sensor 200 Image forming apparatus S Sheet

Claims

1. a sheet discharge port through which a sheet is discharged; a discharge member disposed at the sheet discharge port and configured to convey the sheet in the discharge direction; a sheet discharge tray disposed downstream of the sheet discharge port in the discharge direction and on which the sheet discharged from the sheet discharge port is stacked; a blower mechanism configured to blow an air flow onto the sheet discharged from the sheet discharge port; In a sheet discharge device comprising: the blower mechanism has a blower opening configured to blow an air flow onto the sheet discharged from the sheet discharge port from above; a blower device connected to the blower opening and configured to generate the air flow; and the blower opening is provided above the sheet discharge port, and at least a pair of the blower openings are arranged at the center in the width direction orthogonal to the discharge direction of the sheet, and the air flow from the blower opening is blown obliquely downward from the inner side to the outer side in the width direction of the sheet. A sheet discharge device characterized by this.

2. comprising a control unit configured to control the blower device, the control unit starts blowing the air flow by the blower device after the timing when the leading end of the sheet contacts the sheet discharge tray or the sheet stacked on the sheet discharge tray, and stops blowing the air flow by the blower device at the timing when the trailing end of the sheet contacts the sheet discharge tray or the sheet stacked on the sheet discharge tray. The sheet discharge device according to claim 1, characterized by this.

3. comprising a control unit configured to control the blower device, when continuously discharging the sheet from the sheet discharge port, the control unit drives the blower device at a first speed while the sheet is being discharged from the sheet discharge port, and after the sheet has been discharged from the sheet discharge port and until the subsequent sheet is discharged from the sheet discharge port, the control unit drives the blower device at a second speed smaller than the first speed. The sheet discharge device according to claim 1, characterized by this.

4. when the control unit continuously discharges n sheets from the sheet discharge port, when the leading end of the m-th sheet (1 ≦ m < n) contacts the (m - 1)-th sheet stacked on the sheet discharge tray or the sheet discharge tray, the control unit drives the blower device at the first speed after that timing, When the trailing edge of the m-th sheet contacts the sheet discharge tray or the (m - 1)-th sheet stacked on the sheet discharge tray, switch the blower to drive at the second speed. After the timing when the leading edge of the (m + 1)-th sheet contacts the m-th sheet stacked on the sheet discharge tray, repeat the operation of switching the blower to drive at the first speed again until m + 1 = n. The sheet discharge device according to claim 3, wherein the blower is stopped at the timing when the trailing edge of the n-th sheet contacts the (n - 1)-th sheet stacked on the sheet discharge tray.

5. The sheet discharge device according to claim 1, wherein the blowing angle of the air flow from the air outlet is 15° to 20° when the vertical direction is 0°.

6. The sheet discharge device according to claim 1, wherein the blowing angle of the air flow from the air outlet is adjustable.

7. The sheet discharge device according to claim 1, wherein a plurality of pairs of the air outlets are arranged on both sides with respect to the center in the width direction.

8. A post-processing unit that performs predetermined post-processing on the sheet; The sheet discharge device according to any one of claims 1 to 7, which discharges the sheet that has been post-processed by the post-processing unit; A sheet post-processing device comprising the above.

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

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

11. An image forming unit that forms an image on a sheet; The sheet discharge device according to any one of claims 1 to 7, which discharges the sheet on which an image has been formed by the image forming unit; An image forming device comprising the above.

12. The image forming device according to claim 11, wherein the image forming unit discharges ink onto the sheet to perform image recording.

Images