Sheet discharge device, post-processing device, and image forming system

Abstract

To improve stackability and alignment of a sheet on a sheet discharge tray regardless of the type of the sheet placed on the sheet discharge tray.SOLUTION: A sheet discharge tray 71 is provided with a central tray 72 and an outer peripheral tray 73 having a recessed part 73a formed therein that can contact or face a downstream end surface of the central tray 72 in a discharge direction and both end surfaces in a width direction, thereby forming a large tray surface M integrated with the central tray 72. When the first and second lifting mechanisms 110 and 120 (lifting means) move the outer peripheral tray 73 upward relative to the central tray 72 to form a small tray surface N by the central tray 72 having a smaller area than the large tray surface M, a stopper part 74 is provided in the recessed part 73a with which at least one of a downstream end part in the discharge direction and both end parts in the width direction of the sheet P discharged to the central tray 72 can come into contact.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, post-processing devices connected to image forming devices such as copiers and printers have been known that are equipped with a discharge tray on which sheets discharged in a predetermined discharge direction can be placed (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 1 discloses a technology for improving the alignment of a sheet stack on a sheet output tray after stapling by dividing the output tray (sheet output tray) of a post-processing device capable of stapling into two in the width direction and moving the two output trays up and down so that a step is formed in the height direction. Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional sheet discharge device, depending on the type of sheets placed on the sheet discharge tray, the stackability and alignment of sheets on the sheet discharge tray may be reduced.

[0005] This invention has been made to solve the above-mentioned problems, and aims to provide a sheet discharge device, a post-processing device, and an image forming system that have good stackability and alignment of sheets on the sheet discharge tray regardless of the type of sheets placed on the sheet discharge tray. [Means for solving the problem]

[0006] The sheet discharge device of this invention comprises a sheet discharge tray on which sheets to be discharged in a predetermined discharge direction can be placed, and a wall portion that rises up and down so that the upstream end of the sheet in the discharge direction placed on the sheet discharge tray can come into contact with it.The sheet discharge tray comprises a central tray and an outer peripheral tray that has recesses formed therein that can come into contact with or face the downstream end face of the central tray in the discharge direction and both end faces in the width direction, and can form a large tray surface integrated with the central tray.When the outer peripheral tray is moved upward relatively to the central tray by a lifting means to form a small tray surface by the central tray that is smaller in area than the large tray surface, a stopper portion is provided in the recess that can come into contact with at least one of the downstream end in the discharge direction and both end faces in the width direction of the sheet discharged to the central tray. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a sheet discharge device, a post-processing device, and an image forming system that have good stackability and alignment of sheets on the sheet discharge tray regardless of the type of sheets placed on the sheet discharge tray. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing a sheet discharge device. [Figure 3] FIG. 10 is a diagram showing a state in which a large tray surface is formed on the sheet discharge tray. [Figure 4] 10A and 10B are diagrams illustrating an operation when a small tray surface is used in the sheet discharge tray. [Figure 5] 10 is a flowchart showing control when a small tray surface is used in the sheet discharge tray. [Figure 6] FIG. 2 is a block diagram showing a control system of the image forming system. [Figure 7] FIG. 10 is a perspective view showing a sheet discharge device as a first modified example. [Figure 8] 8A and 8B are diagrams illustrating an operation when a small tray surface is used in the sheet discharge tray in the sheet discharge device of FIG. 7. [Figure 9] 9 is a flowchart showing the control of the operation of FIG. 8. [Figure 10] FIG. 10 is a top view showing a sheet discharge tray according to a second modified example. [Figure 11] FIG. 11 is a side view showing a sheet discharge device according to a third modified example. [Figure 12] 13A and 13B are top views showing the operation of the sheet discharge tray according to a fourth modified example. [Figure 13] 13 is a side view showing the operation of the sheet discharge tray in FIG. 12. FIG. [Figure 14] FIG. 13 is a diagram showing a sheet discharge tray as a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming system 100 will be described with reference to FIG. In this embodiment, the image forming apparatus 1 has a post-processing device 40 detachably installed therein, and together with the post-processing device 40, constitutes one image forming system 100. Image forming apparatus 1 is a multifunction machine equipped with a copy function, a printer function, and a scanner function. A personal computer is connected to image forming apparatus 1 via a network as a remote input device. A user can use the personal computer to issue various commands to image forming apparatus 1 via communication to perform desired printing (image forming operation), or manually operate operation buttons and keys displayed on the screen of operation display panel 95 as an operation unit to issue various commands to perform desired printing (image forming operation). The post-processing device 40 is also equipped with a binding device 80 that performs binding processing on a sheet bundle PT consisting of multiple sheets P stacked thereon, a folding processing device 60 that performs folding processing on the sheets P, and a sheet discharge device 70 that discharges the sheets P and the sheet bundle PT to a discharge tray 71.

[0011] As shown in FIG. 1, a scanner 13 (document reader) that optically reads image information of a document is installed on the top of the image forming apparatus 1. An intermediate transfer belt 8 is also installed above the center of the image forming apparatus 1. Photosensitive drums 2Y, 2M, 2C, and 2K (imaging units) corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged side by side facing the intermediate transfer belt 8. Furthermore, the intermediate transfer belt 8 is pressed against a secondary transfer roller 15 (secondary transfer belt 16) below it, forming a secondary transfer nip as an image forming unit.

[0012] 1, a charging unit 3, a developing unit 4, a cleaning unit 5, a discharging unit, etc. are arranged around the photosensitive drum 2K corresponding to black. Then, an image creation process (charging process, exposure process, developing process, transfer process, cleaning process, discharging process) is carried out on the photosensitive drum 2K, and a black image is formed on the surface of the photosensitive drum 2K.

[0013] The other three photosensitive drums 2Y, 2M, and 2C have substantially the same configuration around them, and images corresponding to the respective toner colors are formed on the surfaces of the photosensitive drums 2Y, 2M, and 2C. Below, we will omit the description of the image formation process on the other three photosensitive drums 2Y, 2M, and 2C as appropriate, and will only describe the image formation process corresponding to black.

[0014] The photosensitive drum 2K is rotated by a main motor in the counterclockwise direction in Fig. 1. Then, at the position of the charging unit 3, the surface of the photosensitive drum 2K is uniformly charged (charging step). Thereafter, the surface of the photosensitive drum 2K reaches the irradiation position of the laser light emitted from the exposure unit 7, and an electrostatic latent image corresponding to black is formed by exposure scanning in the width direction (the direction perpendicular to the paper surface of Figure 1, which is the main scanning direction) at this position (this is the exposure process).

[0015] When the image forming apparatus 1 is used as a copy machine, a latent image is formed on the photosensitive drum 2K by irradiation with laser light from the exposure unit 7 based on image information of an original document read by the scanner 13. On the other hand, when the image forming apparatus 1 is used as a printer, a latent image is formed on the photosensitive drum 2K by irradiation with laser light from the exposure unit 7 based on image information sent from a personal computer.

[0016] Thereafter, the surface of the photosensitive drum 2K reaches a position facing the developing unit 4, where the electrostatic latent image is developed to form a black toner image (developing step). Thereafter, the surface of the photosensitive drum 2K reaches a position facing the intermediate transfer belt 8 and the primary transfer roller 6, and at this position the toner image formed on the surface of the photosensitive drum 2K is primarily transferred onto the surface of the intermediate transfer belt 8 (the primary transfer step). At this time, a small amount of untransferred toner remains on the photosensitive drum 2K.

[0017] Thereafter, the surface of the photosensitive drum 2K reaches a position facing the cleaning unit 5, and at this position, the untransferred toner remaining on the photosensitive drum 2K is collected into the cleaning unit 5 by a cleaning blade (cleaning process). Finally, the surface of the photosensitive drum 2K reaches a position facing the charge removal unit, where the residual potential on the photosensitive drum 2K is removed. Thus, the series of image forming processes performed on the photosensitive drum 2K is completed.

[0018] The above-described image forming process is performed on the surfaces of the other photosensitive drums 2Y, 2M, and 2C in the same manner as on the black photosensitive drum 2K. Then, the toner images of each color formed on the surface of each photosensitive drum 2Y, 2M, 2C, and 2K are primarily transferred onto the intermediate transfer belt 8 in a superimposed manner. In this way, a color image is formed on the intermediate transfer belt 8.

[0019] Thereafter, the intermediate transfer belt 8, onto which the toner images of each color have been primarily transferred in a superimposed state, reaches a position facing a secondary transfer roller 15 (secondary transfer belt 16). At this position, a secondary transfer nip (image forming portion) is formed between the secondary transfer opposing roller 9 and the secondary transfer roller 15, sandwiching the intermediate transfer belt 8 and the secondary transfer belt 16. The four-color toner images formed on the intermediate transfer belt 8 are then secondarily transferred onto a sheet P, such as paper, that has been transported to the position of this secondary transfer nip (secondary transfer process). At this time, untransferred toner that has not been transferred to the sheet P remains on the intermediate transfer belt 8.

[0020] Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit, where untransferred toner and other adhering matter adhering to the surface of the intermediate transfer belt 8 is removed. Thus, the series of transfer processes performed on the intermediate transfer belt 8 is completed.

[0021] Referring to Figure 1, the sheet P transported to the position of the secondary transfer nip (image forming section) is transported from a paper feed section 10 arranged below the image forming apparatus 1 via a transport path K1 on which a paper feed roller 11, a registration roller 12, etc. are arranged. More specifically, a plurality of sheets P such as paper are stacked and stored in the paper feed unit 10. When the paper feed roller 11 is rotated counterclockwise in FIG. 1, the topmost sheet P is fed toward between the registration rollers 12 via a conveying path K1.

[0022] The sheet P conveyed to the registration rollers 12 is temporarily stopped at the roller nip of the registration rollers 12, which have stopped rotating. Then, the registration rollers 12 are rotated in synchronization with the color image on the intermediate transfer belt 8, and the sheet P is conveyed toward the secondary transfer nip (image forming unit). In this way, the desired color image is transferred onto the sheet P.

[0023] Thereafter, the sheet P onto which the color image has been transferred at the secondary transfer nip position is conveyed by the secondary transfer belt 16, and after being separated from the secondary transfer belt 16, is conveyed by the conveying belt 18 to the position of the fixing unit 19. Then, at this position, the color image transferred onto the surface is fixed onto the sheet P by the heat and pressure of the fixing belt and pressure roller (the fixing process). Thereafter, the sheet P is discharged to the outside of the image forming apparatus 1 by the paper discharge rollers 25 via the discharge conveyance path K2. Furthermore, the sheets P discharged from the image forming apparatus 1 are transported inside the post-processing device 40, where they are subjected to post-processing such as binding and folding. The sheets P (sheet stack PT) that have been subjected to post-processing are then discharged onto a sheet discharge tray 71 (sheet discharge device 70). The configuration and operation of the post-processing device 40 (particularly the sheet discharge device 70) will be described in detail later. In this way, a series of image forming processes (image forming operations) in the image forming apparatus 1 is completed.

[0024] The post-processing device 40 will be described in detail below. First, the sheet P discharged from the image forming apparatus 1 is fed (conveyed) into the post-processing device 40 by the inlet rollers 51. When the user has previously selected "normal processing mode" on the operation display panel 95, the conveying path is switched by the switching claw, and the sheet P is conveyed by the conveying roller 52 via the linear conveying path K11, and is discharged from the discharge outlet 40a in a predetermined discharge direction (the direction of the black arrow in the figure) by the discharge roller pair 54, and is stacked (placed) directly on the sheet discharge tray 71.

[0025] On the other hand, when the user has previously selected the "binding processing mode (staple mode)" on the operation display panel 95 of the image forming device 1, the conveying path is switched by the switching claw, and the sheets P are sequentially conveyed via the conveying path K11, and are sequentially stacked on the staple tray 81 of the binding device 80 by conveying by the conveying roller 52 and the auxiliary roller 53. Then, the stapler 82 (binding processing section) performs binding processing on the rear end of the sheets P (sheet stack) on the staple tray 81. Thereafter, the bound sheets P (sheet stack PT) move diagonally upward along the inclination of the staple tray 81 as the guide fence 83, which also functions as a discharge claw, moves in the discharge direction, and is discharged from the discharge outlet 40a by transport by the discharge roller pair 54 and stacked on the sheet discharge tray 71.

[0026] Furthermore, if the user has previously selected "folding mode" on the operation display panel 95 of the image forming apparatus 1, the sheet P is conveyed to the folding device 60 via the vertical conveying path K12 by switching the conveying path using the switching claw. The sheet P conveyed to the folding device 60 is conveyed by the conveying roller 61, and the leading edge of the sheet moves back and forth between two folding rollers 62 and 63 (conveying paths K13 and K14) according to the desired number of folds set by the user, whereby folding processing is performed. Thereafter, the folded sheet P passes through a conveying path K15, is conveyed by a pair of discharge rollers 54, and is discharged from the discharge opening 40a and stacked on the sheet discharge tray 71.

[0027] The configuration and operation of the sheet discharge device 70, which is a feature of the post-processing device 40 (image forming system 100) in this embodiment, will be described in detail below. As explained above using Figure 1 etc., the sheet discharge device 70 (post-processing device 40, image forming system 100) in this embodiment is provided with a sheet discharge tray 71 on which sheets P discharged in a predetermined discharge direction (the direction of the black arrow in Figure 1) can be placed. Specifically, sheets P discharged from the discharge outlet 40a without being post-processed in the post-processing device 40, sheets P discharged from the discharge outlet 40a after binding processing, sheets P discharged from the discharge outlet 40a after folding processing, etc. are each stacked on the sheet discharge tray 71. This sheet discharge tray 71 is formed so that its tray surface (the tray loading surface on which the sheet P is placed) is inclined upward from the upstream side in the discharge direction (the right side in Figure 1) to the downstream side in the discharge direction (the left side in Figure 1). 1 to 3, the sheet discharge device 70 (post-processing device 40) is provided with a vertically erect wall 40b that can come into contact with the upstream end (rear end) of the sheet P in the discharge direction placed on the sheet discharge tray 71. This wall 40b is part of the exterior surface of the exterior cover of the post-processing device 40, and is formed with a discharge opening 40a for discharging the sheet P outside the device. The rear end of the sheet P that slides obliquely downward along the inclination of the tray surface of the sheet discharge tray 71 hits the wall 40b, and functions as a positioning member (alignment member). It should be noted that the wall portion 40b and the rear end portion (upstream side in the discharge direction) of the sheet discharge tray 71 do not necessarily need to be in contact with each other; rather, it is preferable to provide a gap large enough to at least not hinder the sheet discharge tray 71 from moving up and down. 2, the sheet discharge device 70 is provided with a filler 99 that can swing about a support shaft and that can come into contact with the upper surface of the sheets P stacked on the sheet discharge tray 71. The movement of the filler 99 is detected by a photosensor (not shown), and the lifting means is controlled based on the detection result to adjust the lifting position of the sheet discharge tray 71.

[0028] 2 to 4, the sheet discharge tray 71 in this embodiment is mainly composed of a central tray 72 and an outer peripheral tray 73. As shown in FIG. The central tray 72 is formed in the center of the sheet discharge tray 71 . The outer tray 73 has recesses 73a (concave notches) formed therein that can come into contact with (or face opposite with a small gap between) the downstream end face (tip end face) in the discharge direction and both widthwise end faces of the center tray 72. That is, the center tray 72 is formed so as to be able to fit into the recesses 73a of the outer tray 73. The outer periphery tray 73 is configured to be able to form a large tray surface M (see FIGS. 3, 10, etc.) integrated with the center tray 72. That is, when the center tray 72 is fitted into the recess 73a of the outer periphery tray 73, the large tray surface M is formed as the tray surface of the entire sheet discharge tray 71.

[0029] The sheet discharge tray 71 has a stopper portion 74 in the recess 73a (outer peripheral tray 73) that can come into contact with at least one of the downstream end in the discharge direction and both widthwise ends (in this embodiment, the downstream end in the discharge direction) of the sheet P discharged to the central tray 72 when the outer peripheral tray 73 is moved upward relative to the central tray 72 by the first and second lifting mechanisms 110 and 120 as lifting means to form a small tray surface N (a tray surface of the central tray 72 having a smaller area than the large tray surface M; see Figures 4, 10, etc.).

[0030] In detail, referring to Figure 2, the lifting means is composed of a first lifting mechanism 110 that lifts and lowers the central tray 72 by driving a first lifting motor 111, and a second lifting mechanism 120 that lifts and lowers the outer tray 73 together with the stopper portion 74 by driving a second lifting motor 121. The first lifting mechanism 110 is composed of a first lifting motor 111, a two-stage gear 112, a pair of timing belts 113, a holder 114, etc. The two-stage gear 112 is composed of a gear portion that meshes with the motor gear of the first lifting motor 111, a pulley portion around which one end of one of the timing belts 113 is wound, etc. The pair of timing belts 113 are provided at an interval in the width direction (the direction perpendicular to the paper surface of FIGS. 3 and 4), with one directly wound around the two-stage gear 112 and the other wound around a pulley to which the drive of the two-stage gear 112 is transmitted via a shaft portion. The holders 114 are fixed to the pair of timing belts 113 that are provided at an interval in the width direction, are members that hold the center tray 72, and are configured to be slidable in the vertical direction along a guide portion (not shown) formed on the housing of the device. The second lifting mechanism 120 also includes a second lifting motor 121, a two-stage gear 122, a pair of timing belts 123, and a holder 124. The two-stage gear 122 includes a gear portion that meshes with the motor gear of the second lifting motor 121, and a pulley portion around which one end of one of the timing belts 123 is wound. The pair of timing belts 123 are provided with a gap in the width direction, with one directly wound around the two-stage gear 122 and the other wound around a pulley to which the drive of the two-stage gear 122 is transmitted via a shaft portion. The holders 124 are fixed to the pair of timing belts 123 that are provided with a gap in the width direction, and are members that hold the outer periphery tray 73 and are configured to be slidable in the vertical direction along a guide portion (not shown) formed on the housing of the device. By configuring the lifting means with two lifting mechanisms 110, 120 in this way, the central tray 72 and the outer peripheral tray 73 can be moved up and down at different times, thereby simplifying the control operation.

[0031] Then, referring to Figure 4 etc., in this embodiment, when a sheet P that can be placed on the small tray surface N (a sheet having a sheet surface that fits within the range of the small tray surface N) is discharged, the first and second lifting mechanisms 110, 120 (lifting means) move the outer tray 73 upward relative to the central tray 72 to form the small tray surface N.

[0032] Specifically, in this embodiment, when sheets that have been folded by the folding device 60 (in the example of FIG. 4, these are Z-folded sheets P1 to Pn) are discharged onto the sheet discharge tray 71 by the sheet discharge device 70, the first and second lifting mechanisms 110, 120 (lifting means) move the outer tray 73 upward relative to the center tray 72, forming a small tray surface N. The area of ​​the sheet surface of the folded sheet P is smaller than that of the sheet P before folding by the amount of folding, so that the sheet can be placed on the small tray surface N. Similarly, when a sheet P having a small sheet surface area is discharged as is without post-processing or when the sheet P is discharged after binding processing, a small tray surface N is also formed. By providing a step between the outer tray 73 and the central tray 72 and discharging small-sized sheets P toward the small tray surface N (central tray 72), the stackability and alignment of the sheets P can be improved compared to when small-sized sheets P are discharged toward the large tray surface M. Furthermore, by providing a step between the outer peripheral tray 73 and the central tray 72 in this way, when the sheet P is discharged toward the small tray surface N (central tray 72), the stopper portion 74 is positioned at the step, so that the sheet P discharged from the discharge opening 40a does not slip under the outer peripheral tray 73, but instead hits the stopper portion 74 and is stacked on the small tray surface N, as shown in Fig. 4. Note that the step formed between the outer peripheral tray 73 and the central tray 72 at this time is preferably optimized (adjusted) depending on the number of sheets stacked on the small tray surface N, the thickness of the sheet P, whether or not folding is performed, etc., so that the sheet P discharged from the discharge opening 40a hits the stopper portion 74.

[0033] 3, when a sheet P (a sheet of a size that protrudes beyond the small tray surface N) that cannot be placed on the small tray surface N but can be placed on the large tray surface M is discharged, the first and second lifting mechanisms 110, 120 (lifting means) move the outer tray 73 relative to the center tray 72 so that they are at the same height, thereby forming the large tray surface M. In other words, the first and second lifting mechanisms 110, 120 are controlled to move so that the tray surfaces of the outer tray 73 and the center tray 72 form a single plane without any steps. In this embodiment, the state (position) in which the large tray surface M is formed as shown in FIG. 3 is set as the reference state (reference position) in terms of control. In addition, whether to eject the sheet P using the large tray surface M or the small tray surface N is determined by the control unit 90 (see Figures 1 and 6) based on the sheet size information and post-processing information input by the user to the operation display panel 95 (see Figure 1).

[0034] In this way, the sheet discharge device 70 in this embodiment can improve the stackability and alignment of sheets P on the sheet discharge tray 71 regardless of the type of sheets P placed on the sheet discharge tray 71 (such as sheet size and whether or not they have been folded).

[0035] Hereinafter, the operation when the small tray surface N is used in the sheet discharge device 70 will be described with reference to FIGS. In addition, in the description of the operation, the operation of the sheet discharge device 70 will be described appropriately using FIG. 4, and the control flow will be described using the flowchart of FIG. When the control unit 90 determines to discharge the sheets P using the small tray surface N (central tray 72) based on the printing information (especially the information related to the sheet size and post-processing) input by the user to the operation display panel 95 (see FIGS. 1 and 6), first, as shown in FIG. 4(A), with the sheet discharge tray 71 in the reference state (the state shown in FIG. 3), the second lifting mechanism 120 lifts the outer tray 73 (step S1). In the example of FIG. 4, it is assumed that a command has been given to discharge n sheets P1 (P2, ... Pn) that have been Z-folded by the folding device 60. 4(B), the first Z-folded sheet P1 discharged from the discharge port 40a is stacked on the central tray 72 (small tray surface N) (step S2). At this time, the first sheet P1 is discharged so as to hit the stopper portion 74 of the outer peripheral tray 73 that has been moved upward, and is stacked favorably on the small tray surface N with its position in the discharge direction aligned (aligned). Thereafter, it is determined whether a subsequent sheet P2 is to be discharged (step S3), and if it is determined that the subsequent Z-folded sheet P2 is to be discharged, it is determined from the operation of the above-mentioned filler 99 (see FIG. 2) whether the height of the sheet surface (upper surface) of the already stacked sheet P1 is normal (a height position at which the subsequent sheet P2 can be stacked) (step S4). If the result shows that the height of the sheet surface is not normal, the first lifting mechanism 110 lowers the center tray 72 to a position where the height is normal, as shown in FIG. 4(C) (step S5). 4(D), the second Z-folded sheet P2 discharged from the discharge port 40a is stacked on the center tray 72 (small tray surface N) at the normal height (step S6). At this time, the second sheet P2 is discharged so as to hit the stopper 74 of the outer peripheral tray 73 that has been moved upward, and is stacked well on the small tray surface N with its position in the discharge direction aligned (aligned). Thereafter, it is determined whether or not there is a subsequent sheet Pn (step S7), and if it is determined that there is a sheet Pn, the flow from step S4 onwards is repeated as shown in Figures 4(E) to 4(F). On the other hand, if it is determined in step S7 that there is no subsequent sheet Pn, the second lifting mechanism 120 lowers the outer tray 73 to the position of the center tray 72 and stops it there (steps S8 and S9), as shown in Figure 4(G), and this flow ends. If it is determined in step S3 that there is no subsequent sheet P, the flow from step S8 onwards is carried out, and this flow ends.

[0036] The image forming system 100 configured as above is entirely controlled by a control system as shown in FIG. The image forming apparatus 1 and the post-processing apparatus 40 are connected to each other so that they can communicate with each other. The post-processing apparatus 40 is provided with a control unit 90 that includes a CPU, a storage unit, a communication interface with the image forming apparatus 1, and the like. The storage unit of the control unit 90 is configured with a ROM, a RAM, etc., and stores programs to be executed by the CPU, etc. The control unit 90 is connected to a detection unit 91 including a sensor that detects the presence or absence of a sheet P and the position of a driving member, etc., and a drive unit 92 including first and second lifting motors 111, 121, etc. The control unit 90 (CPU) operates the drive unit 92 in accordance with the program stored in the memory unit based on instructions sent from the image forming device 1, information on the sheet P sent from the detection unit 91, and information on the status of each drive mechanism, thereby performing the desired post-processing on the sheet P transported from the image forming device 1.

[0037] <Variation 1> As shown in FIG. 7, the lifting mechanism 130 as the lifting means in the sheet discharge device 70 in variant 1 lifts and lowers the central tray 72 and the outer tray 73 simultaneously, or only one of them (the central tray 72 in this variant 1), by switching using a clutch 132 as a switching mechanism that can connect or disconnect the drive of a single lifting motor 131. In detail, the lifting mechanism 130 (lifting means) in variant example 1 is composed of a lifting motor 131, a two-stage gear 112, a pair of first timing belts 113, a holding portion 114, a clutch 132 (switching mechanism), a pulley 122, a pair of second timing belts 123, a holding portion 124, etc. When the clutch 132 is not engaged, the drive of the lift motor 131 is transmitted to the two-stage gear 112 but not to the pulley 122, allowing only the center tray 72 to be raised and lowered. On the other hand, when the clutch 132 is engaged, the drive of the lift motor 131 is transmitted to both the two-stage gear 112 and the pulley 122, allowing the center tray 72 and the outer tray 73 to be raised and lowered simultaneously. By configuring the lifting means as the lifting mechanism 130 consisting of one lifting motor 131 in this way, it is possible to reduce the cost and size of the lifting mechanism.

[0038] Hereinafter, with reference to FIGS. 8 and 9, an operation when the small tray surface N is used in the sheet discharge device 70 in the first modified example will be described. In addition, in the description of the operation, the operation of the sheet discharge device 70 will be described appropriately using FIG. 8, and the control flow will be described using the flowchart of FIG. When the control unit 90 determines to discharge sheets P using small tray surface N (central tray 72) based on printing information input by the user to the operation display panel 95 (see FIGS. 1 and 6), first, in the sheet discharge tray 71 in the standard state (the state shown in FIG. 8A), the clutch 132 (switching mechanism) is released (step S10), and the lifting mechanism 130 lowers the central tray 72 (step S11), as shown in FIG. 8B. Note that in the example of FIG. 8, it is assumed that a command is given to discharge n sheets P1 (P2, ... Pn) that have been Z-folded by the folding device 60. Then, the clutch 132 (switching mechanism) is engaged (step S12), and the central tray 72 and the outer peripheral tray 73 are simultaneously raised by the lifting mechanism 130 (step S13), as shown in Fig. 8(C). The lifting stop position at this time is a height at which the first sheet P1 can be placed on the central tray 72 (small tray surface N). Then, the clutch 132 (switching mechanism) is again released (step S14), and the same flow as steps S2 to S7 previously described using Fig. 4 is performed to stack the desired number n of sheets P1 to Pn on the center tray 72 (small tray surface N) as shown in Figs. 8(D) to (G). At this time, each of the sheets P1 to Pn is discharged so that it hits the stopper portion 74 of the outer peripheral tray 73 located above the center tray 72, and therefore the sheets are stacked well on the small tray surface N with their positions in the discharge direction aligned (aligned). Thereafter, the clutch 132 (switching mechanism) is engaged again (step S15), and the lifting mechanism 130 simultaneously lowers the central tray 72 and the outer tray 73 by the amount that the central tray 72 has finally lowered, as shown in FIG. 8(F) (step S16). Then, the clutch 132 (switching mechanism) is again released (step S17), and the central tray 72 is raised to the position of the outer tray 73 as shown in Figure 8 (G) and stopped there (steps S18, S19), thereby ending this flow. Furthermore, even in the sheet discharge device 70 configured and controlled in this manner, the stackability and alignment of the sheets P on the sheet discharge tray 71 can be improved regardless of the type of sheets P (sheet size, post-processing contents) placed on the sheet discharge tray 71.

[0039] <Variation 2> As shown in Figure 10, the sheet discharge tray 71 in variant example 2 has sheet detection sensors 150A to 150C (for example, reflective photosensors) installed on the outer peripheral tray 73 (so as not to protrude from the tray surface of the outer peripheral tray 73) as sheet detection means that can optically detect the state in which a sheet P that cannot be placed on the small tray surface N (central tray 72) but can be placed on the large tray surface M is placed thereon. In detail, a first sheet detection sensor 150A capable of detecting whether the discharge direction size of the sheet P is large or small relative to the discharge direction range of the central tray 72 (small tray surface N) is installed near the downstream side in the discharge direction of the recess 73a in the outer tray 73 (left side in Figure 10). In addition, second sheet detection sensors 150B and 150C are installed near both ends of the width direction (vertical direction in Figure 10) of the recess 73a in the outer tray 73, which can detect whether the width direction size of the sheet P is large or small relative to the width direction range of the central tray 72 (small tray surface N). When these sheet detection sensors 150A to 150C detect that sheets P are stacked and protruding from the small tray surface N, the large-sized sheets P are properly stacked on the large tray surface M by locking part or all of the lifting mechanism so that no step is created between the central tray 72 and the outer tray 73.

[0040] <Variation 3> As shown in Figure 11, in the sheet discharge device 70 of variant example 3, the stopper portion 74 is configured to expand and contract in accordance with the amount of movement when the outer tray 73 moves upward relative to the central tray 72 by a lifting means (in the example of Figure 2, the first and second lifting mechanisms 110 and 120) that raises and lowers the central tray 72 and the outer tray 73. Such expandable stopper portion 74 may be, for example, a plate or wire made of an elastic material such as rubber and connected to the outer tray 73 and the center tray 72 . By using such a stopper portion 74, the stackability and alignment of the sheet bundle PT on the central tray 72 can be further improved.

[0041] <Variation 4> As shown in FIGS. 12 and 13, in the sheet discharge tray 71 in the fourth modification, the central tray 72 is configured to be deformable so that the area of ​​the small tray surface N can be changed. The outer peripheral tray 73 is configured to be deformable so that the area of ​​the recess 73a can be changed in accordance with the change in the area of ​​the small tray surface N. Specifically, a storage tray 72x that can be stored inside the central tray 72 is installed. Also, a storage tray 73x that can be stored inside the peripheral tray 73 (recess 73a) is installed. 12(A) and 13(A), when the storage tray 73x is stored in the outer peripheral tray 73 (when the area of ​​the recessed portion 73a is large), the storage tray 72x is pulled out from the center tray 72 (when the area of ​​the small tray surface N is large) so that no gaps are created in the recessed portion 73a when viewed from above. On the other hand, when the storage tray 73x is pulled out from the outer peripheral tray 73 (when the area of ​​the recessed portion 73a is small), as shown in FIG. 12(B) and 13(B), the storage tray 72x is stored in the center tray 72 (when the area of ​​the small tray surface N is small) so that no gaps are created in the recessed portion 73a when viewed from above. By configuring it in this manner, the size of the small tray surface N of the central tray 72 can be adjusted (optimized) to match the size of the sheets P stacked on the small tray surface N, thereby further improving the stackability and consistency of the sheets P discharged onto the central tray 72 regardless of the size of the sheets P stacked on the small tray surface N. In variant example 4, the sheet discharge tray 71 (central tray 72, peripheral tray 73) is configured so that the size of the small tray surface N in the discharge direction can be changed, but the sheet discharge tray 71 (central tray 72, peripheral tray 73) can also be configured so that the size of the small tray surface N in the width direction can be changed.

[0042] <Variation 5> As shown in Figure 14, the sheet discharge tray 71 in variant example 5 has a first stopper portion 74 that can be contacted by the downstream end in the discharge direction of the sheet P discharged to the central tray 72 when the outer tray 73 is moved upward relative to the central tray 72 by the lifting means (first and second lifting mechanisms 110 and 120 in the example of Figure 2) to form a small tray surface N, and also has a second stopper portion 75 in the recess 73a that can be contacted by both widthwise ends of the sheet P discharged to the central tray 72. This makes it possible to improve stackability and alignment in the width direction as well as the discharge direction for the sheets P discharged onto the central tray 72 (small tray N).

[0043] As described above, the sheet discharge device 70 (post-processing device 40) in this embodiment is provided with the sheet discharge tray 71 on which sheets to be discharged in a predetermined discharge direction can be placed, and the wall portion 40b that stands up in the vertical direction and is capable of contacting the upstream end of the sheet P placed on the sheet discharge tray 71 in the discharge direction. The sheet discharge tray 71 is further provided with the central tray 72 and the outer peripheral tray 73 that is formed with recesses 73a that are capable of contacting or facing the downstream end face in the discharge direction and both end faces in the width direction of the central tray 72, and that is capable of forming an integrated large tray surface M together with the central tray 72. When the first and second lifting mechanisms 110, 120 (lifting means) move the outer tray 73 upward relative to the central tray 72 to form a small tray surface N by the central tray 72 having a smaller area than the large tray surface M, a stopper portion 74 is provided in the recess 73a with which at least one of the downstream end in the discharge direction and both widthwise ends of the sheet P discharged to the central tray 72 can come into contact. As a result, regardless of the type of sheets P placed on the sheet discharge tray 71, the stackability and alignment of the sheets P on the sheet discharge tray 71 are improved.

[0044] In this embodiment, the present invention is applied to the sheet discharge device 70 of the post-processing device 40 connected to a color image forming device 1, but the present invention can naturally also be applied to the sheet discharge device of a post-processing device connected to a monochrome image forming device. Furthermore, in this embodiment, the present invention is applied to the sheet discharge device 70 of the post-processing device 40 connected to the electrophotographic image forming device 1, but the application of the present invention is not limited to this, and the present invention can also be applied to the sheet discharge device of the post-processing device connected to other types of image forming devices (for example, inkjet type image forming devices, stencil printing devices, etc.). Furthermore, in this embodiment, the present invention is applied to an image forming system 100 in which a post-processing device 40 and an image forming device 1 are installed, but the present invention can also be applied to an independent device that is not connected to the image forming device 1 and serves as a post-processing device (sheet processing device). Furthermore, in this embodiment, the present invention is applied to a post-processing device 40 in which a binding device 80 and a folding device 60 are installed, but the present invention can also be applied to post-processing devices that perform other post-processing or multiple combinations of post-processing including other post-processing. Furthermore, in this embodiment, the present invention is applied to the sheet discharge device 70 installed in the post-processing device 40, but the present invention can naturally also be applied to sheet discharge devices installed in other devices (for example, the image forming device 1). Even in such cases, the same effects as those of this embodiment can be obtained.

[0045] It is to be noted that the present invention is not limited to the present embodiment, and it is clear that the present embodiment can be appropriately modified within the scope of the technical concept of the present invention in addition to the modifications suggested in the present embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. of the components can be any number, position, shape, etc. that is suitable for implementing the present invention.

[0046] In this specification, the term "sheet" is not limited to paper, but is defined to include all sheet-like recording media, such as coated paper, label paper, and OHP sheets. In the present specification, the "width direction" is defined as a direction substantially perpendicular to the "discharge direction" of the sheet. [Explanation of symbols]

[0047] 1. Image forming device, 40 post-processing device (sheet processing device), 40a outlet, 40b wall, 60 folding processing device, 70 sheet ejection device, 71 sheet discharge tray (sheet discharge section), 72 Center tray (center), 72x storage trays, 73 Outer tray (outer), 73a recess, 73x storage trays, 74 stopper part, 75 second stopper portion, 99 filler, 100 Image forming system, 110 first lifting mechanism (lifting means), 111 first lift motor, 120 second lifting mechanism (lifting means), 121 second lift motor, 130 lifting mechanism (lifting means), 131 lifting motor, 132 Clutch (switching mechanism), 150A to 150C sheet detection sensor (sheet detection means), P, P1, P2, Pn sheets, PT sheet stack, M large tray surface, N Small tray surface.

[0048] The present invention can also be embodied in a combination of Supplementary Notes 1 to 10, for example, as follows. (Appendix 1) a sheet discharge tray on which sheets discharged in a predetermined discharge direction can be placed; a wall portion that stands upright in the vertical direction so that the upstream end of the sheet placed on the sheet discharge tray can come into contact with the wall portion; Equipped with The sheet discharge tray is A central tray; a peripheral tray having recesses formed on a downstream end surface of the central tray in the discharge direction and on both end surfaces in the width direction, the recesses being capable of contacting or facing each other, and capable of forming an integrated large tray surface together with the central tray; Equipped with A sheet discharge device characterized in that a stopper portion is provided in the recess with which at least one of the downstream end in the discharge direction and both widthwise ends of a sheet discharged to the central tray can come into contact when the outer peripheral tray is moved upward relatively to the central tray by a lifting means to form a small tray surface of the central tray having a smaller area than the large tray surface. (Appendix 2) When a sheet that can be placed on the small tray surface is discharged, the lifting means moves the outer tray relatively upward with respect to the center tray to form the small tray surface, The sheet ejection device described in Appendix 1 is characterized in that when a sheet that cannot be placed on the small tray surface but can be placed on the large tray surface is ejected, the lifting means moves the outer tray relative to the central tray so that they are at the same height position, thereby forming the large tray surface. (Appendix 3) The sheet ejection device described in Appendix 1 or Appendix 2, characterized in that the lifting means includes a first lifting mechanism that lifts and lowers the central tray by driving a first lifting motor, and a second lifting mechanism that lifts and lowers the outer peripheral tray by driving a second lifting motor. (Appendix 4) The sheet ejection device described in Appendix 1 or Appendix 2 is characterized in that the lifting means lifts and lowers the central tray and the outer tray simultaneously or only one of them by switching using a switching mechanism that can connect or disconnect the drive of one lifting motor. (Appendix 5) A sheet discharge device as described in any one of Appendix 1 to Appendix 4, characterized in that a sheet detection means capable of detecting a state in which a sheet that cannot be placed on the small tray surface but can be placed on the large tray surface is placed on the outer tray. (Appendix 6) The sheet ejection device described in any one of Appendix 1 to Appendix 5, characterized in that the stopper portion expands and contracts in accordance with the amount of movement when the outer tray is moved upward relative to the center tray by the lifting means. (Appendix 7) The central tray is configured to be deformable so that the area of ​​the small tray surface can be changed, The sheet ejection device described in any one of Appendix 1 to Appendix 6, characterized in that the outer tray is configured to be deformable so that the area of ​​the recess can be changed in accordance with changes in the area of ​​the small tray surface. (Appendix 8) A post-processing device that performs post-processing on a sheet, A post-processing device comprising the sheet discharge device according to any one of Supplementary Notes 1 to 7. (Appendix 9) A folding processing device is provided to fold the sheet, The post-processing device described in Appendix 8, characterized in that when the sheet that has been folded by the folding processing device is discharged to the sheet discharge tray by the sheet discharge device, the lifting means moves the outer tray relatively upward with respect to the center tray to form the small tray surface. (Appendix 10) 10. An image forming system comprising: an image forming apparatus that forms an image on a sheet; and a post-processing apparatus according to claim 8 or 9. [Prior art documents] [Patent documents]

[0049] [Patent Document 1] Japanese Patent Application Publication No. 11-334971

Claims

1. a sheet discharge tray on which sheets discharged in a predetermined discharge direction can be placed; a wall portion that stands upright in the vertical direction so that the upstream end of the sheet placed on the sheet discharge tray can come into contact with the wall portion; Equipped with The sheet discharge tray is A central tray; a peripheral tray having recesses formed on a downstream end surface of the central tray in the discharge direction and on both end surfaces in the width direction, the recesses being capable of contacting or facing each other, and capable of forming an integrated large tray surface together with the central tray; Equipped with A sheet discharge device characterized in that a stopper portion is provided in the recess with which at least one of the downstream end in the discharge direction and both widthwise ends of a sheet discharged to the central tray can come into contact when the outer peripheral tray is moved upward relatively to the central tray by a lifting means to form a small tray surface of the central tray having a smaller area than the large tray surface.

2. When a sheet that can be placed on the small tray surface is discharged, the lifting means moves the outer tray relatively upward with respect to the center tray to form the small tray surface, 2. The sheet ejection device according to claim 1, wherein when a sheet that cannot be placed on the small tray surface but can be placed on the large tray surface is ejected, the lifting means moves the outer tray relative to the central tray so that the outer tray is at the same height position as the central tray, thereby forming the large tray surface.

3. The sheet ejection device according to claim 1 or claim 2, characterized in that the lifting means comprises a first lifting mechanism that lifts and lowers the central tray by driving a first lifting motor, and a second lifting mechanism that lifts and lowers the outer peripheral tray by driving a second lifting motor.

4. The sheet ejection device according to claim 1 or claim 2, characterized in that the lifting means lifts and lowers the central tray and the outer peripheral tray simultaneously or only one of them by switching using a switching mechanism that can connect or disconnect the drive of a single lifting motor.

5. 3. The sheet ejection device according to claim 1, wherein a sheet detection means is installed on the outer peripheral tray, capable of detecting a state in which a sheet that cannot be placed on the small tray surface but can be placed on the large tray surface is placed on the outer peripheral tray.

6. 3. The sheet ejection device according to claim 1, wherein the stopper portion expands and contracts in accordance with the amount of movement of the outer peripheral tray when the lifting means moves the outer peripheral tray upward relative to the central tray.

7. The central tray is configured to be deformable so that the area of ​​the small tray surface can be changed, 3. The sheet ejection device according to claim 1, wherein the outer peripheral tray is configured to be deformable so that the area of ​​the recess can be changed in accordance with a change in the area of ​​the small tray surface.

8. A post-processing device that performs post-processing on a sheet, A post-processing device comprising the sheet discharge device according to claim 1 or 2.

9. A folding processing device is provided to fold the sheet, 9. The post-processing device according to claim 8, wherein when the sheet that has been folded by the folding processing device is discharged onto the sheet discharge tray by the sheet discharge device, the lifting means moves the outer tray upward relative to the center tray to form the small tray surface.

10. An image forming system comprising: an image forming apparatus for forming an image on a sheet; and the post-processing apparatus according to claim 8.

Images