Sheet discharge device and sheet post-processing device having the same and image formation system

Abstract

To provide a sheet discharge device that is difficult to be damaged, a sheet post-processing device having the same, and an image formation system.SOLUTION: A protruding member is supported to move reciprocally between a protruding position and a retracted position. At the protruding position, the protruding member protrudes from a discharge port toward above a loading tray, guides a tip of a sheet discharged by a pair of discharge rollers to contact its upper surface in a discharge direction. At the retracted position, the protruding member retracts from above the loading tray. A movement mechanism has a support holder that movably supports the protruding member and moves the held protruding member between the protruding position and the retracted position. It further includes a detection unit that detects whether or not the protruding member is in the retracted position, and the detection unit is disposed in the support holder.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet discharge device, a sheet post-processing device including the same, and an image forming system. [Background technology]

[0002] A conventional sheet post-processing device is equipped with a sheet discharge device. The sheet discharge device includes a pair of discharge rollers, a stacking tray, a protruding member, and a moving mechanism. The pair of discharge rollers discharge sheets from a discharge port. The stacking tray is disposed downstream of the pair of discharge rollers in the sheet discharge direction, and the sheets discharged by the pair of discharge rollers are stacked on the stacking tray.

[0003] The protruding member is supported so as to be reciprocally movable between a protruding position and a retracted position. At the protruding position, the protruding member protrudes above the stacking tray from the discharge port and guides the leading edge of the sheet discharged by the pair of discharge rollers in the discharge direction by contacting the upper surface of the protruding member. At the retracted position, the protruding member retracts from above the stacking tray. The movement mechanism moves the protruding member between the protruding position and the retracted position. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-135204 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in conventional sheet discharge devices, when a detection unit is provided to detect whether the protruding member is in the retracted position, there is a possibility that the detection unit may come into contact with surrounding parts and be damaged when the protruding member moves.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide a sheet discharge device that is less likely to be damaged. [Means for solving the problem]

[0007] To achieve the above object, a sheet discharge device according to a first aspect of the present invention includes a pair of discharge rollers, a stacking tray, a protruding member, a support holder, and a movement mechanism. The pair of discharge rollers discharges sheets from a discharge opening. The stacking tray is disposed downstream of the pair of discharge rollers in the sheet discharge direction, and receives sheets discharged by the pair of discharge rollers. The protruding member is supported so as to be reciprocally movable between a protruding position and a retracted position. At the protruding position, the protruding member protrudes above the stacking tray from the discharge opening, and guides the leading edge of the sheet discharged by the pair of discharge rollers in the discharge direction by contacting its upper surface with the top surface. At the retracted position, the protruding member retracts from above the stacking tray. The movement mechanism has a support holder that movably supports the protruding member, and moves the held protruding member between the protruding position and the retracted position. The movement mechanism further includes a detection unit that detects whether the protruding member is in the retracted position, and the detection unit is disposed in the support holder. [Effects of the Invention]

[0008] The configuration of the present invention can provide a sheet discharge device that is hard to break, and a sheet post-processing device and an image forming system that include the same. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an image forming system S including an image forming apparatus 200 and a sheet post-processing device 5 according to an embodiment of the present invention; [Figure 2] FIG. 1 is a side cross-sectional view schematically illustrating the internal structure of a sheet ejection device 10 according to an embodiment of the present invention. [Figure 3] 1 is a perspective view showing a structure around a protruding member 13 of a sheet ejection device 10 according to an embodiment of the present invention; FIG. [Figure 4] FIG. 1 is an enlarged perspective view showing a structure around a protruding member 13 of a sheet ejection device 10 according to an embodiment of the present invention. [Figure 5] 1 is a side view showing a support holder 20 of a sheet ejection device 10 according to an embodiment of the present invention from an axial direction. [Figure 6] FIG. 1 is an enlarged perspective view showing a structure around a tip of a protruding member 13 of a sheet ejection device 10 according to an embodiment of the present invention. [Figure 7] 1 is a cross-sectional view perpendicular to the vertical direction of a support holder 20 of a sheet ejection device 10 according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a sheet post-processing device 5 according to an embodiment of the present invention and an image forming system S including the sheet post-processing device 5 will be described with reference to the drawings.

[0011] <1. Image Forming System Configuration> 1 is a schematic diagram of an image forming system S including an image forming apparatus 200 and a sheet post-processing device 5 according to one embodiment of the present invention. The image forming system S includes the image forming apparatus 200 and the sheet post-processing device 5.

[0012] Image forming apparatus 200 is a so-called monochrome multifunction peripheral that is equipped with functions such as printing, scanning (image reading), and facsimile transmission. Image forming apparatus 200 includes document transport unit 203 and image reading unit 204. Document transport unit 203 is placed on the top surface of main body unit 201. Image reading unit 204 is located below document transport unit 203, in a position Z2, inside main body unit 201. An image of a document loaded on document transport unit 203 or an image of a document placed on a contact glass (not shown) on the top surface of image reading unit 204 is read by image reading unit 204.

[0013] The image forming apparatus 200 further includes a sheet feeding unit 205 , a sheet conveying unit 206 , an exposure unit 207 , an image forming unit 208 , a transfer unit 209 , a fixing unit 210 , a sheet discharge unit 211 , a relay unit 212 , and a main body control unit 213 .

[0014] The sheet feeding unit 205 stores multiple sheets P and separates and sends out the sheets P one by one during printing. The sheet conveying unit 206 conveys the sheets P sent out from the sheet feeding unit 205 to a transfer unit 209 and a fixing unit 210, and further distributes the fixed sheets P to a sheet discharge unit 211 or a relay unit 212. The exposure unit 207 irradiates the image forming unit 208 with laser light controlled based on image data.

[0015] The image forming unit 208 includes a photosensitive drum 2081, which is an image carrier, and a developing device 2082. In the image forming unit 208, an electrostatic latent image of the original image is formed on the surface of the photosensitive drum 2081 by laser light irradiated from the exposure unit 207. The developing device 2082 supplies toner to this electrostatic latent image to develop it, thereby forming a toner image. The transfer unit 209 transfers the toner image formed on the surface of the photosensitive drum 2081 by the image forming unit 208 onto a sheet P. The fixing unit 210 heats and pressurizes the sheet P onto which the toner image has been transferred, thereby fixing the toner image to the sheet P.

[0016] After fixing, the sheet P is sent to the sheet discharge section 211 or the relay section 212. The sheet discharge section 211 is arranged below the image reading section 204 in Z2. The sheet discharge section 211 has an opening on the front side, and the printed paper (printed material) is removed from the front side. The relay section 212 is arranged below the sheet discharge section 211. The downstream end of the relay section 212 in the paper transport direction is connected to the sheet post-processing device 5. The printed paper (printed material) sent to the relay section 212 passes through the relay section 212 and is transported to the sheet post-processing device 5.

[0017] The main body control unit 213 includes a CPU, an image processing unit, a memory unit, and other electronic circuits and electronic components (not shown). The CPU controls the operation of each component provided in the image forming apparatus 200 based on control programs and data stored in the memory unit to perform processing related to the functions of the image forming apparatus 200. The sheet feeding unit 205, the sheet conveying unit 206, the exposure unit 207, the image forming unit 208, the transfer unit 209, and the fixing unit 210 each receive individual commands from the main body control unit 213 and print on the sheet P in cooperation with each other. The memory unit is configured by a combination of a non-volatile storage device such as a program ROM (Read Only Memory) or a data ROM (not shown) and a volatile storage device such as a RAM (Random Access Memory), for example.

[0018] The sheet post-processing device 5 is detachably connected to a side surface of the image forming apparatus 200. The sheet post-processing device 5 includes a post-processing housing 50, a sheet transport path 42 arranged in the post-processing housing 50, a processing tray 8, a punching processing section 61, a stapling processing section 62, a transport roller pair 71, an intermediate roller pair 72, a first sheet detection section S1, a discharge roller pair 73, a second sheet detection section S2, a sheet discharge device 10, and a post-processing control section 100.

[0019] In this embodiment, a post-processing mechanism is configured by the punching processing unit 61 and the stapling processing unit 62. That is, the sheet post-processing device 5 includes a post-processing mechanism, which performs predetermined post-processing on the sheet P and transports the post-processed sheet P to the sheet discharge device 10.

[0020] A sheet entrance 41 is provided on the side of the post-processing housing 50 facing the image forming apparatus 200. The sheet P that has passed through the relay section 212 passes through the sheet entrance 41 and is carried into the inside of the sheet post-processing apparatus 5.

[0021] The sheet transport path 42 extends from the sheet entrance 41 to a position Z1 above the processing tray 8 in a direction away from the image forming apparatus 200 (to the left in FIG. 1). The processing tray 8 is capable of temporarily stacking sheets P on its upper surface. The sheet transport path 42 stacks the sheets P, which have been carried in through the sheet entrance 41, on the upper surface of the processing tray 8.

[0022] The processing tray 8 is inclined downward from the downstream end toward the upstream end in the sheet conveying direction (X1-X2 direction).

[0023] The punching processing unit 61 is disposed between the sheet entrance 41 and the downstream end of the sheet conveying path 42 in the sheet conveying direction (X1-X2 direction). The punching processing unit 61 performs a punching process on the sheet P conveyed through the sheet conveying path 42. The punching process is a process of forming punch holes (binding holes). Here, punch holes are punched along one side edge of the sheet in the width direction (Y1-Y2 direction) perpendicular to the sheet conveying direction (X1-X2 direction).

[0024] The staple processing unit 62 is disposed below the sheet transport path 42 in Z2, on the upstream side X2 in the sheet transport direction (X1-X2 direction) of the processing tray 8. The staple processing unit 62 performs a staple process (binding process) on the stack of sheets P stacked on the processing tray 8. The stapling process is a process of binding the stack of sheets P with staples. Here, a so-called edge binding process is performed in which the corners or ends of the sheet stack are bound with staples.

[0025] The post-processing mechanism includes a pair of transport rollers 71, a pair of intermediate rollers 72, and a first sheet detection unit S1 arranged in order from the upstream side X2 in the sheet transport direction, and the pair of transport rollers 71 and the pair of intermediate rollers 72 transport the sheet P that has been post-processed to the sheet discharge device 10.

[0026] The transport roller pair 71 is adjacent to the downstream side of the perforation processing unit 61 in the sheet transport direction (X1-X2 direction). The transport roller pair 71 transports the sheet after perforation processing or the sheet that has not been perforated to the downstream side X2 in the sheet transport direction.

[0027] The intermediate roller pair 72 is disposed at the downstream end of the sheet conveying path 42 in the sheet conveying direction (X1-X2 direction). The intermediate roller pair 72 is located above Z1 the upstream end of the processing tray 8. The intermediate roller pair 72 discharges the sheet P, which has been conveyed from the sheet entrance 41 into the sheet conveying path 42, onto the processing tray 8.

[0028] The first sheet detection unit S1 is disposed immediately downstream of the intermediate roller pair 72 in the sheet discharge direction (see FIG. 2). The first sheet detection unit S1 is a sensor that optically detects a sheet, and detects when the leading edge of a sheet being conveyed by the conveying roller pair 71 enters the intermediate roller pair 72. The first sheet detection unit S1 also detects when the sheet being conveyed by the intermediate roller pair 72 has passed through the intermediate roller pair 72.

[0029] <2. Structure of the sheet discharge device> 2 is a side cross-sectional view that schematically shows the internal structure of the sheet discharge device 10. The sheet discharge device 10 includes a discharge roller pair 73, a stacking tray 11, a sheet pressing member 14, a paddle member 15, and a post-processing control unit 100. In addition to the above-described components, the sheet discharge device 10 also includes a protruding member 13, a moving mechanism 26, and a detection unit 90, the details of which will be described later.

[0030] The discharge roller pair 73 discharges the sheet from the discharge port 2. The discharge roller pair 73 is disposed downstream of the intermediate roller pair 72 in the sheet discharge direction. The discharge roller pair 73 overlaps with the downstream end of the processing tray 8 in the sheet discharge direction.

[0031] The discharge roller pair 73 is made up of a drive roller 731 (discharge roller) and a driven roller 732 that is pressed against the drive roller 731 with a predetermined nip pressure. The drive roller 731 and the driven roller 732 form a nip portion 73N that nip and transports the sheets P. The nip portion 73N is released by a nip release mechanism (not shown) when the staple processing is performed by the staple processing unit 62. The sheets P are stacked on the processing tray 8 with the nip portion 73N released. The stapled sheet stack is discharged onto the stacking tray 11 by the discharge roller pair 73 with the nip portion 73N restored.

[0032] The drive roller 731 is supported by a drive roller shaft 731a and rotates integrally with the drive roller shaft 731a. A drive source such as a motor (not shown) is connected to the drive roller shaft 731a, and its rotation is controlled by the post-processing control unit 100. When the drive roller shaft 731a rotates, the two drive rollers 731 simultaneously rotate integrally with the drive roller shaft 731a.

[0033] The second sheet detection unit S2 is disposed immediately downstream of the pair of discharge rollers 73. The second sheet detection unit S2 is composed of an actuator and a photosensor (both not shown), and can detect whether a sheet is being discharged and whether the trailing edge of the sheet has passed the pair of discharge rollers 73.

[0034] The stacking tray 11 is disposed downstream of the pair of discharge rollers 73 in the discharge direction of the sheets P, and stacks the sheets P discharged by the pair of discharge rollers 73. The stacking tray 11 is supported so as to be able to move up and down. A sheet stacking surface 11a is formed on the top surface of the stacking tray 11. A sheet receiving wall 11b forms the side of the post-processing housing 50 opposite the image forming device 200. The sheet stacking surface 11a is inclined so as to transition upward Z1 as it moves away from the sheet receiving wall 11b. The upstream end of the sheet stacking surface 11a in the sheet discharge direction is located below the pair of discharge rollers 73 Z2.

[0035] The stacking tray 11 is a final discharge location for sheets in the sheet post-processing device 5. The sheet stack that has been stapled in the processing tray 8 is discharged toward the stacking tray 11 by the discharge roller pair 73 and stacked on the sheet stacking surface 11a. If stapling is not performed by the staple processing unit 62, the sheets P are transported to the stacking tray 11 without being stacked on the processing tray 8.

[0036] The post-processing control unit 100 includes a CPU (not shown) and other electronic circuits and electronic components (not shown). The post-processing control unit 100 is communicably connected to the main body control unit 213. The post-processing control unit 100 receives commands from the main body control unit 213 and, based on control programs and data stored in the storage unit using the CPU, controls the operation of each component (such as the punching unit 61, stapling unit 62, conveying roller pair 71, intermediate roller pair 72, discharge roller pair 73, processing tray 8, sheet discharge device 10, and movement mechanism 26) provided in the sheet post-processing device 5, thereby performing processing related to the functions of the sheet post-processing device 5.

[0037] The sheet pressure member 14 is disposed upstream of the stacking tray 11 in the sheet discharge direction. The sheet pressure member 14 is disposed below the drive roller shaft 731a at Z2. Two sheet pressure members 14 are disposed in the sheet width direction (Y1-Y2 direction) of the stacking tray 11 at a predetermined interval.

[0038] The sheet pressure member 14 is supported at its lower end so as to be swingable about a swing shaft 14a extending along the sheet width direction (Y1-Y2 direction). The sheet pressure member 14 swings around the swing shaft 14a in the sheet discharge direction with one upper end as the free end. The sheet pressure member 14 swings between a position where it presses the upstream portion of the sheet stacked on the stacking tray 11 in the discharge direction from above Z1, and a position where it releases pressure on the sheet. The swing of the sheet pressure member 14 is controlled by the post-processing control unit 100.

[0039] The sheet pressing member 14 presses the rear end of the sheet P stacked on the sheet stacking surface 11a from above Z1. As a result, even if the discharged sheet is curled, the rear end of the sheet can be pressed down to straighten the curl.

[0040] A plurality of paddle members 15 (four in this example) are provided coaxially with the drive roller shaft 731a. The paddle members 15 rotate independently of the drive roller shaft 731a. The four paddle members 15 are connected to a drive source such as a motor (not shown), and their rotation is controlled by the post-processing control unit 100.

[0041] Before the start of the sheet discharge operation, the sheet pressing member 14 is stopped at a position where it does not protrude toward the stacking tray 11 so as not to interfere with the discharge of the sheet P. Furthermore, before the start of the sheet operation, the paddle member 15 waits at a position where it does not protrude toward either the processing tray 8 side or the stacking tray 11 side so as not to interfere with the discharge of the sheet P.

[0042] The post-processing control unit 100 starts rotating the paddle member 15 after the rear end of the sheet P (the upstream end in the sheet discharge direction) has passed through the nip portion 73N and before the sheet P is stacked on the sheet stacking surface 11a. The paddle member 15 then comes into contact with the rear end of the sheet P discharged from the discharge roller pair 73, and presses the vicinity of the rear end of the sheet P from above Z1, pushing it down toward the sheet stacking surface 11a.

[0043] When the paddle member 15 rotates further from this state, the paddle member 15 pulls the sheet P along the stacking tray 11 toward the upstream side in the discharge direction of the sheet P, and presses the vicinity of the rear end of the sheet P toward the sheet receiving wall 11b of the stacking tray 11.

[0044] Furthermore, the paddle member 15 starts to rotate, and the sheet pressing member 14 starts to swing before the paddle member 15 passes the upstream end in the sheet discharge direction of the stacking tray 11. Then, the sheet pressing member 14 moves to a pressing position where it presses the upstream portion in the discharge direction of the sheets stacked on the stacking tray 11 from above Z1.

[0045] Then, when the sheet stacking operation by the sheet post-processing device 5 is completed, the upstream end of the sheet P in the discharge direction comes into contact with the sheet receiving wall 11b provided on the upstream side of the stacking tray 11 in the sheet discharge direction. As a result, the sheet P is aligned at a predetermined position on the stacking tray 11.

[0046] 3. Configuration of protruding member and moving mechanism Fig. 3 is a perspective view showing the structure around the protruding member 13 of the sheet discharge device 10, and Fig. 4 is an enlarged perspective view showing the structure around the protruding member 13. Fig. 5 is a side view showing the support holder 20 from the axial direction. In Fig. 5, the detecting section 90 is hatched to make it clearer. Fig. 6 is an enlarged perspective view showing the structure around the tip of the protruding member 13.

[0047] The protruding member 13 is a rod-shaped member that extends in an arc shape along the sheet discharge direction. The protruding member 13 is arranged below the sheet discharge outlet 2 in Z2 (see FIG. 2). More specifically, the protruding member 13 is arranged below the discharge path of the sheet that is discharged from the discharge roller pair 73 along the processing tray 8 in Z2. A plurality of protruding members 13 (two in this embodiment) are arranged at predetermined intervals with the center of the stacking tray 11 sandwiched between them in the sheet width direction (Y1-Y2 direction). The protruding members 13 and the paddle member 15 are aligned in the sheet width direction (Y1-Y2 direction).

[0048] The support holder 20 is fixed to the post-processing housing 50 and is included in a moving mechanism 26, which will be described later. One support holder 20 is provided at a position overlapping each of the protruding members 13 in the sheet width direction (Y1-Y2 direction) (see FIG. 3).

[0049] The support holder 20 has side walls 21a and 21b, a guide rail 22, a cover rib 23, and a positioning protrusion 24 (see FIGS. 3 and 5).

[0050] The side walls 21a and 21b are plate-shaped portions formed on both ends of the support holder 20 in the axial direction (Y1-Y2 direction). The side walls 21a and 21b face each other in the axial direction (Y1-Y2 direction). A collar support hole 25 penetrating the side walls 21a and 21b in the axial direction (Y1-Y2 direction) is formed in the side walls 21a and 21b. The protruding member 13 is disposed between the side walls 21a and 21b in the axial direction (Y1-Y2 direction).

[0051] The guide rails 22 are rib-shaped and protrude from the side wall portions 21a and 21b toward the inside of the support holder 20 in the axial direction (Y1-Y2 direction). The guide rails 22 extend parallel to the movement direction of the protruding member 13 along the arc shape of the protruding member 13. The cover rib 23 is provided opposite the guide rails 22 in a direction perpendicular to the axial direction (Y1-Y2 direction) and the sheet discharge direction. A gap is formed between the cover rib 23 and the guide rails 22.

[0052] The protruding member 13 is disposed between the guide rail 22 and the cover rib 23. The protruding member 13 is supported so as to be movable back and forth between a protruding position P1 and a retracted position P2 along the guide rail 22. The support holder 20 movably holds the protruding member. Hereinafter, the direction in which the protruding member 13 moves will be simply referred to as the "moving direction."

[0053] The protruding position P1 is a position where the protruding member 13 protrudes from the support holder 20 in the movement direction (the position shown by the two-dot chain line in FIGS. 2 and 3). More specifically, the protruding position P1 is a position where the protruding member protrudes from the discharge opening 2 to the upper Z1 of the stacking tray 11 and brings the leading edge of the sheet P discharged by the discharge roller pair 73 into contact with the upper surface to guide it in the discharge direction. The retracted position P2 is a position where the protruding member 13 retracts to the inside of the support holder 20 in the movement direction (the position shown by the solid line in FIG. 2 and the dashed and solid lines in FIG. 5). More specifically, the retracted position P2 is a position where the protruding member 13 retracts from the upper Z1 of the stacking tray 11.

[0054] Of the movement directions, the direction in which the protruding member 13 moves toward the protruding position P1 is referred to as the "protruding direction," and the direction in which the protruding member 13 moves toward the retracted position P2 is referred to as the "retracted direction."

[0055] The positioning protrusion 24 is connected to the lower end (the downstream end in the retraction direction) of the guide rail 22. The positioning protrusion 24 protrudes from the guide rail 22 so as to be perpendicular to the guide rail 22. The positioning protrusion 24 faces the protruding member 13 in the movement direction (see FIG. 5).

[0056] The protruding member 13 moves in the retraction direction, and when it reaches the retracted position P2, it abuts against the positioning protrusion 24. In this state, the protruding member 13 is restricted from moving in the retraction direction by the positioning protrusion 24, and is positioned at the retracted position P2 at a reference position P2' that is the farthest from the protruding position P1. When the protruding member 13 is at the reference position P2', the tip of the protruding member 13 (the downstream end in the protruding direction) is located inside (upstream in the protruding direction) the tip of the support holder 20.

[0057] The moving mechanism 26 moves the protruding member 13 between the protruding position P1 and the retracted position P2. The moving mechanism 26 includes the support holder 20, the rotation shaft 32, the pinion gear 27, the rack gear 31, and the drive device 131. That is, the moving mechanism 26 has the support holder 20.

[0058] The rotation shaft 32 extends parallel to the drive roller shaft 731a. The rotation shaft 32 is inserted into the collar support hole 25 of each support holder 20. The rotation shaft 32 faces the protrusion member 13 in the radial direction. A pinion gear 27 is fitted onto the rotation shaft 32 (see FIG. 4).

[0059] The pinion gear 27 is a spur gear having a plurality of gear teeth on its outer circumferential surface. The rotation shaft 32 passes through the radial center of the pinion gear 27. One pinion gear 27 is arranged along the longitudinal direction of the rotation shaft 32 at a position overlapping with each of the protruding members 13. The pinion gear 27 is located between the pair of side wall portions 21a, 21b of the support holder 20 in the axial direction (Y1-Y2 direction). The pinion gear 27 faces the protruding member 13 in the radial direction.

[0060] The rack gear 31 is a rack gear consisting of a plurality of gear teeth arranged along the movement direction of the protruding member 13. The rack gear 31 is formed on a surface 37 of the protruding member 13 facing the pinion gear 27 (see FIG. 6).

[0061] The rack gear 31 is engageable with the pinion gear 27. When the pinion gear 27 and the rack gear 31 are engaged with each other, they form a rack-and-pinion gear mechanism with the pinion gear 27 as the pinion gear. In other words, when the pinion gear 27 rotates with the pinion gear 27 and the rack gear 31 engaged with each other, the rack gear 31 moves in the rotation direction of the pinion gear 27. This causes the protruding member 13 to move.

[0062] The driving device 131 is composed of a driving motor 807, a driving force transmission pulley 806, and a driving force transmission belt 805 (see FIG. 3). The driving motor 807 has a main body 808, a motor shaft 809 protruding from the main body 808, and a motor gear 810 fixed to the end of the motor shaft 809, and outputs a rotational driving force via the motor shaft 809 and the motor gear 810. The rotation control (rotation angle, rotation speed, etc.) of the driving motor 807 is performed by the post-processing control unit 100.

[0063] The drive transmission pulley 806 is a toothed pulley fixed to the rotary shaft 32 and rotates integrally with the rotary shaft 32. The drive transmission belt 805 is an endless toothed belt wound around the motor gear 810 and the drive transmission pulley 806.

[0064] When a rotational driving force is output from the drive motor 807, the motor gear 810 rotates, and the rotational driving force is transmitted to the rotation shaft 32 via the drive transmission belt 805 and the drive transmission pulley 806, causing the rotation shaft 32 to rotate. When the rotation shaft 32 rotates, as described above, the two protrusion members 13 are simultaneously moved between the protrusion position P1 and the retracted position P2 by the movement mechanism 26.

[0065] <4. Configuration of the detection unit> FIG. 7 is a cross-sectional view perpendicular to the up-down direction (Z1-Z2 direction) of the support holder 20. In FIG. 7, the protruding member 13 is indicated by a dashed line. The detection unit 90 is disposed on the support holder 20 and detects whether the protruding member 13 is in the retracted position P2. More specifically, the detection unit 90 is disposed at the lower end (the downstream end in the retracted direction) of the guide rail 22 (see FIG. 5). The detection unit 90 is also disposed upstream of the positioning protrusion 24 in the retracted direction. This allows the detection unit 90 to detect that the protruding member 13 is in the retracted position P2 before the protruding member 13 reaches the positioning protrusion 24.

[0066] More specifically, the detection unit 90 is configured with an optical sensor 91 including a light-emitting unit 91a and a light-receiving unit 91b arranged opposite each other. In this embodiment, the light-emitting unit 91a is arranged on the side wall 21a, and the light-receiving unit 91b is arranged on the side wall 21b. The light-emitting unit 91a and the light-receiving unit 91b face each other in the width direction (Y1-Y2 direction) of the sheet P. Alternatively, the light-emitting unit 91a may be arranged on the side wall 21b, and the light-receiving unit 91b may be arranged on the side wall 21a.

[0067] In the past, when the detection unit 90 was disposed on the protruding member 13, the detection unit 90 moved together with the protruding member 13. At this time, there was a possibility that the detection unit 90 would come into contact with surrounding components and be damaged. Also, there was a possibility that the lead wires connected to the detection unit 90 would come into contact with surrounding components and be damaged. In contrast, in this embodiment, the detection unit 90 is disposed on the support holder 20. This prevents the detection unit 90 and the lead wires connected to the detection unit 90 from coming into contact with surrounding components when the protruding member 13 moves. Therefore, it is possible to provide a sheet discharge device 10 that is less likely to be damaged.

[0068] The detection unit 90 detects that the protruding member 13 is at the retracted position P2 when the protruding member 13 enters the optical path of the optical sensor 91. Furthermore, the detection unit 90 detects that the protruding member 13 is not at the retracted position P2 when the protruding member 13 retracts from the optical path of the optical sensor 91. This allows the detection unit 90 to more accurately detect the entry or retraction of the protruding member 13.

[0069] When the post-processing control unit 100 detects that the protruding member 13 is in the retracted position P2, it stops driving the moving mechanism 26. This prevents the moving mechanism 26 from continuing to drive even when the protruding member 13 is in the retracted position P2, which could result in damage to the protruding member 13 and the support holder 20.

[0070] Furthermore, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the image forming apparatus 200 of the image forming system S is a multifunction machine for monochrome printing, but this is not limited to this. The image forming apparatus 200 may be, for example, a monochrome copier or a monochrome printer, or may be an image forming apparatus for color printing, such as a color copier or a color printer.

[0071] For example, the detection unit 90 may be provided on both of the two support holders 20 corresponding to the two protruding members 13, or on only one of them.

[0072] In addition, in this embodiment, the optical sensor 91 is used as the detection unit 90, but the present invention is not limited to this. Instead of the optical sensor 91 as the detection unit 90, a contact type sensor may be used. [Industrial Applicability]

[0073] The present invention can be used in a sheet post-processing device that is disposed downstream of an image forming apparatus and performs predetermined post-processing on sheets discharged from the image forming apparatus. [Explanation of symbols]

[0074] 2 outlet 2 Sheet outlet 5 Sheet post-processing device 8 Processing Tray 10 Sheet ejection device 11 Loading tray 11a Sheet loading surface 11b Sheet receiving wall 13. Protruding member 14 Sheet retainer 14a Oscillating shaft 15 Paddle member 20 Support Holder 21a, 21b side wall part 22 Guide rail 23 Cover Rib 24 Positioning protrusion 25 Collar support hole 26 Moving mechanism 27 Pinion gear 31 Rack Gear 32 Rotation axis 37 Opposite Surface 41 Sheet entrance 42 Sheet transport path 50 Aftertreatment Housing 61 Perforation processing section 62 Staple processing section 71 Transport roller pair 72 Intermediate Roller Pair 73 Discharge Roller Pair 73N nip part 90 Detection unit 91 Light Sensor 91a Light-emitting part 91b Light receiving part 100 Post-processing control unit 131 Drive unit 200 Image forming device 201 Main body 203 Document transport unit 204 Image reading unit 205 Sheet feeding section 206 Sheet transport unit 207 Exposure section 208 Image forming unit 209 Transcription Department 210 Fixing unit 211 Sheet discharge section 212 Relay Section 213 Main unit control section 731 Drive Roller 731a Drive roller shaft 732 Driven roller 805 Drive transmission belt 806 Drive transmission pulley 807 Drive motor 808 Main body 809 Motor shaft 810 Motor Gear 2081 Photosensitive drum 2082 Developing device P-sheet P1 protrusion position P2 Evacuation position P2′ Reference position S Image Forming System S1 First sheet detection unit S2 Second sheet detection unit

Claims

1. a pair of discharge rollers for discharging the sheet from a discharge port; a stacking tray disposed downstream of the pair of discharge rollers in a discharge direction of the sheet, on which the sheet discharged by the pair of discharge rollers is stacked; a protruding member supported so as to be reciprocally movable between a protruding position that protrudes from the discharge port above the stacking tray and that brings the leading edge of the sheet discharged by the pair of discharge rollers into contact with an upper surface to guide the sheet in the discharge direction, and a retracted position that retracts from above the stacking tray; a movement mechanism having a support holder that movably supports the protruding member, and that moves the protruding member between the protruding position and the retracted position; In a sheet ejection device comprising: a detector that detects whether the protruding member is in the retracted position, The sheet ejection device, wherein the detection unit is disposed on the support holder.

2. 2. The sheet ejection device according to claim 1, wherein the detection unit is composed of an optical sensor including an opposing light-emitting unit and a light-receiving unit, and detects whether the protruding member is in the retracted position when the protruding member enters or retracts from the optical path of the optical sensor.

3. the optical sensor is disposed at a downstream end of the protruding member in the retraction direction, The sheet ejection device according to claim 2 , wherein the detection unit detects that the protruding member is at the retracted position when the protruding member enters the optical path of the optical sensor.

4. a sheet ejection device according to claim 1 or 2; a post-processing mechanism that performs predetermined post-processing on the sheet and transports the post-processed sheet to the sheet discharge device.

5. The sheet post-processing device according to claim 4 ; an image forming apparatus that forms an image on the sheet and transports the sheet after the image formation to the sheet post-processing apparatus.

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