Discharging device, image forming device, and post-processing device

Abstract

To provide a discharging device, an image forming device and a post-processing device capable of suppressing discharging failure of a long sheet.SOLUTION: A plurality of guide members are arranged at predetermined intervals in the sheet discharge direction, inclined relative to the upper surface, which serves as the sheet placement portion, of the extension tray 204, which serves as a discharge tray, and which guide discharged sheets, which are sheets being discharged. The discharged sheets guided by the guide members fly out from the tip of the guide members due to the conveying force, and separate from the stacked sheets stacked on the extension tray 204. The discharged sheets then fall while tracing a parabola, and come into contact with the stacked sheets again at a position away from the guide members. This reduces the contact period and area of the discharged sheets with the stacked sheets, and suppresses the discharged sheets from sticking to the stacked sheets.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a discharging device, an image forming apparatus, and a post-processing device.

Background Art

[0002] Conventionally, a discharging device having a discharge tray for discharging sheets is known.

[0003] Patent Document 1 describes, as the above-described discharging device, a discharge tray including a rotatable movable tray disposed on the upstream side in the sheet discharge direction and a fixed tray disposed on the downstream side in the sheet discharge direction. The movable tray rotates about a fulcrum on the upstream side in the sheet discharge direction by the weight of the sheet bundle discharged onto the discharge tray, thereby gently changing the inclination angle of the discharged sheet bundle. As a result, the conveyance resistance of the sheet being discharged (hereinafter referred to as the discharged sheet) that is conveyed while sliding on the sheet bundle on the discharge tray is reduced, and the occurrence of trailing edges remaining at the nip of the discharge roller pair is suppressed, and it is described that smooth sheet discharge can be performed.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of a long sheet with high surface smoothness, there is a risk that the sheet may stick to the sheet placed on the discharge tray (hereinafter referred to as the stacked sheet), resulting in poor sheet discharge such as the above-described trailing edges remaining or buckling.

Means for Solving the Problems

[0005] In order to solve the above-described problems, the present invention provides a discharging device having a discharge tray for discharging sheets, wherein a plurality of guide members that are inclined with respect to the sheet placement portion of the discharge tray and guide the sheet being discharged are arranged at a predetermined interval in the sheet discharge direction.

Effects of the Invention

[0006] According to the present invention, it is possible to suppress defective discharge of a long sheet.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. It should be noted that those skilled in the art can easily make changes and modifications to the present invention within the scope of the claims to form other embodiments, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode in the present invention and does not limit the scope of the claims.

[0009] FIG. 1 is a schematic diagram of the entire image forming system of the present embodiment. The image forming system 300 includes a high-capacity paper feeder 101, an image forming apparatus main body 100, and a post-processing apparatus 200. The high-capacity paper feeder 101 feeds sheets to the image forming apparatus main body 100, and can load long sheets with a length in the sheet conveyance direction of 700 mm to 1300 mm.

[0010] The image forming apparatus main body 100 forms an image on a sheet based on the input image data or the image data of the read image. For example, a copier, a printer, a facsimile machine, or a digital multi-functional machine having at least two of these functions corresponds to this. The image forming apparatus main body 100 is of a known method such as an electrophotographic method or a droplet ejection method, and any image forming method may be used. The post-processing apparatus 200 performs post-processing such as sorting, edge binding, center binding, and punching.

[0011] An operation display unit 102 is provided above the image forming apparatus main body 100. An image is formed on the sheet fed from the high-capacity paper feeder 101 or the paper feeding unit of the image forming apparatus main body 100 based on the image data in the image forming unit of the image forming apparatus main body 100. The sheet on which the image is formed is discharged to the post-processing apparatus 200. The post-processing apparatus 200 performs predetermined post-processing such as sorting, edge binding, center binding, and punching on the sheet on which the image sent from the image forming apparatus main body 100 is formed, and then discharges it to a predetermined discharge tray.

[0012] FIG. 2 is a schematic configuration diagram of the post-processing apparatus 200. The post-processing apparatus 200 has a first conveyance path A having a punch unit PU as post-processing means for performing post-processing on the sheet, and an upper paper discharge path B for conveying the sheet to an upper discharge tray 201 as a discharge tray. It also has a lower paper discharge path C for conveying the sheet to the lower discharge tray 202. The post-processing apparatus 200 has a second conveyance path D for conveying the sheet to a processing tray F for performing alignment and staple binding, etc.

[0013] The sheet discharged from the image forming apparatus main body 100 is conveyed by the pair of conveying rollers 1 to 4 arranged in the first conveying path A, and then is sorted by the branching claws T1 and T2 to the upper discharge path B, the lower discharge path C, and the second conveying path D.

[0014] The sheet guided to the upper discharge path B by the branching claws T1 and T2 is conveyed by the pair of conveying rollers 5 to 8, and then is discharged to the upper discharge tray 201 by the pair of upper discharge rollers 9. On the other hand, the sheet guided to the lower discharge path C by the branching claws T1 and T2 is conveyed by the pair of conveying rollers 10 and 11, and then is discharged to the lower discharge tray 202 by the pair of lower discharge rollers 12.

[0015] The sheet guided to the second conveying path D by the branching claw T1 is conveyed to the pair of conveying rollers 13 to 17 and then is directly conveyed to the processing tray F. Or, it is conveyed in a switchback manner, the rear end of the sheet is conveyed to the press stack path E, waits for the arrival of the subsequent sheet, and performs superimposed conveyance.

[0016] Specifically, first, when the rear end of the sheet passes through the branching claw T3 arranged at the confluence of the second conveying path D and the press stack path E, the branching claw T3 rotates by the biasing force of the low-load spring, and the rear end of the sheet is guided to the press stack path E as shown in the figure. Then, after the rear end of the sheet passes through the branching claw T3, the sheet is conveyed in a switchback manner by the pair of conveying rollers 14, 15, and 16, and the rear end of the sheet is conveyed to the press stack path. When the front end of the sheet reaches the pair of conveying rollers 15, the switchback conveyance of the sheet is stopped, and it waits for the arrival of the subsequent sheet. Then, the subsequent sheet conveyed to the second conveying path D is conveyed while superimposing on the preceding sheet. When the superimposed conveyance as described above is repeated to form a stack of sheets with a preset number, it is conveyed to the processing tray F.

[0017] The stack of sheets conveyed to the processing tray F has its rear end placed on the stopper portion 62, and the movable fence 42 is moved in the conveying direction and abutted against the front end of the stack of sheets for alignment. After alignment, the stapler SP as a post-processing means performs an operation of stapling the sheets. After stapling, it is discharged to the lower discharge tray 202 by the pair of lower discharge rollers 12.

[0018] On the other hand, when the saddle-stitching process is instructed, the stack of sheets on the processing tray F is sent to the saddle-stitching conveyance path G by the diverting claws T4 without being stapled by the stapler SP. The stack of sheets sent to the saddle-stitching conveyance path G is conveyed by the pair of conveying rollers 20 and 21 and then saddle-stitched by the saddle-stitching stapler SSP as a post-processing means. After that, the stack of sheets saddle-stitched by the saddle-folding roller 22 is folded in half and then discharged to the saddle-stitching tray 203.

[0019] Sheet detection sensors 31 to 36 for detecting the conveyance timing are arranged on each of the conveyance paths A to D. If an error is detected by the sheet detection sensors 31 to 36, the system conveyance is stopped.

[0020] In addition, an extension tray 204 as a discharge tray is connected to the lower discharge tray 202, and long sheets with a sheet conveyance direction length of 700 mm to 1300 mm can be stacked.

[0021] For long sheets with a sheet conveyance direction length of 700 mm to 1300 mm, sticking may occur to the sheets stacked on the extension tray 204 (hereinafter referred to as stacked sheets) when the surface smoothness is high, such as coated paper. When sticking occurs, there is a risk of the following paper discharge defects. That is, the movement of the discharged sheet may stop at the stuck portion, and there is a risk of buckling of the discharged sheet on the discharge tray 202 or a remaining rear end of the discharged sheet remaining on the lower paper discharge roller pair 12. In addition, there was a risk that the stuck stacked sheet would move in the discharge direction together with the discharged sheet and fall from the lower discharge tray 202.

[0022] When the discharged sheet is a long sheet, the sliding period with the stacked sheet is longer and the contact area between the discharged sheet and the stacked sheet is larger than that of a normal-sized sheet. Therefore, when the long sheet is a sheet with high surface smoothness such as coated paper and is likely to stick, there is a risk of sticking to the stacked sheet.

[0023] Therefore, in the present embodiment, a plurality of guide members for guiding the discharge sheet on the extension tray 204 so as to be separated from the stacking sheet are provided at a predetermined interval in the sheet discharge direction, thereby suppressing the occurrence of sticking during the paper discharge of the long sheet. Hereinafter, the characteristic parts of the present embodiment will be described with reference to the drawings.

[0024] FIG. 3 is a schematic configuration diagram of the extension tray 204 of the present embodiment. FIG. 3(a) shows a first state in which all the guide members 210a and 210b are located at the storage positions stored in the extension tray 204, and FIG. 3(b) shows a second state in which all the guide members 210a and 210b are located at the guide positions. Further, FIG. 3(b) shows a third state in which the second guide member 210b at the most downstream in the sheet discharge direction is located at the stopper position for stopping the sheet, and the first guide member 210a is located at the guide position.

[0025] As shown in FIG. 3, in the extension tray 204 of the present embodiment, the first guide member 210a and the second guide member 210b are arranged at a predetermined interval in the sheet discharge direction. The first guide member 210a is attached to the first rotation shaft 211a and is rotatably held with respect to the extension tray 204. The second guide member 210b is attached to the second rotation shaft 211b and is rotatably held with respect to the extension tray 204.

[0026] The width of each of the guide members 210a and 210b is substantially the same as the width of the extension tray 204, and the first guide member 210a and the second guide member 210b are arranged at an interval of 200 to 220 mm in the sheet discharge direction. In the present embodiment, two guide members are arranged on the extension tray 204, but three or more guide members may be arranged, and the number of guide members, the arrangement interval and width of the guide members may be appropriately set according to the device configuration such as the paper discharge line speed.

[0027] Each guide member 210a, 210b is rotationally driven by a guide motor 231 (see FIG. 5) described later, and can take the storage position shown in FIG. 3(a) and the guide position shown in FIG. 3(b). Further, the second guide member 210b at the most downstream in the sheet discharge direction can further take the stopper position shown in FIG. 3(c).

[0028] When the guide member is in the guide position shown in FIG. 3(b), the angle formed by the guide member and the upper surface (sheet placement surface) of the extension tray 204 is about 30°, and the height from the upper surface of the extension tray 204 to the tip of the guide member is about 15 to 20 mm. Note that the above angle and height are examples, and may be appropriately set according to the device configuration. Also, when the second guide member 210b shown in FIG. 3(c) is in the stopper position, the angle formed by the guide member and the upper surface (sheet placement surface) of the extension tray 204 is about 90°.

[0029] As shown in FIG. 3(b), when the guide member is in the guide position, the stacked sheets loaded on the extension tray 204 bend so as to hang down from the top of the guide member. On the other hand, the discharged sheet being discharged by the lower paper discharge roller pair 12 is guided upward by the guide member, and then jumps obliquely upward by the conveying force of the lower paper discharge roller pair 12 from the tip of the guide member. As a result, the discharged sheet is separated from the stacked sheets.

[0030] The discharged sheet that has jumped out from the tip of the guide member falls by its own weight and contacts the stacked sheets again. However, between the tip of the guide member and the re-contact point of the discharged sheet, it floats up and is separated from the stacked sheets, and an air layer is formed between the stacked sheets and the discharged sheet. As a result, the sliding period of the discharged sheet with the stacked sheets and the contact area with the stacked sheets are reduced, and even when the discharged sheet is a long sheet with high surface smoothness, sticking to the stacked sheets is well suppressed. As a result, discharge defects such as remaining at the rear end, buckling, and dropping of the stacked sheets can be well suppressed.

[0031] In the case of a long sheet with a conveyance direction length such that the tip of the loading sheet is positioned in front of the second guide member 210b, it is set to the third state shown in Fig. 3(c). Thereby, the second guide member 210b can regulate the movement of the sheet in the discharge direction, and the sheet drop from the extension tray 204 can be prevented.

[0032] Fig. 4 is a schematic configuration diagram showing a part of a guide drive device 230 that drives each of the guide members 210a and 210b. As shown in Fig. 4, the driving force of a guide motor is transmitted to the first rotating shaft 211a to which the first guide member 210a is attached via a first timing belt 212a and a first clutch mechanism 220a. The driving force of a guide motor 231 (see Fig. 5) is transmitted to the second rotating shaft 211b to which the second guide member 210b is attached via the first timing belt 212a, a second timing belt 212b, and a second clutch mechanism 220b.

[0033] Each of the clutch mechanisms 220a and 220b has a clutch shaft 221a and 221b. At one end of the clutch shaft 221a of the first clutch mechanism 220a, a first output pulley 213a to which the driving force is transmitted from the first timing belt 212a and a second input pulley 214b to which the driving force is transmitted to the second timing belt 212b are attached. At one end of the clutch shaft 221b of the second clutch mechanism 220b, a second output pulley 213b to which the driving force is transmitted from the second timing belt 212b is attached.

[0034] Also, a first forward one-way clutch 222a and a first reverse one-way clutch 223a are attached to the clutch shaft 221a of the first clutch mechanism 220a. A second forward one-way clutch 222b and a second reverse one-way clutch 223b are attached to the clutch shaft 221b of the second clutch mechanism 220b.

[0035] When the guide motor rotates forward, each forward one-way clutch 222a, 222b is drivingly connected to the clutch shaft and rotates together with the clutch shafts 221a, 221b. When the guide motor rotates in reverse, they rotate freely with respect to the clutch shafts 221a, 221b. On the other hand, when the guide motor rotates forward, each reverse one-way clutch 223a, 223b rotates freely with respect to the clutch shafts 221a, 221b. When the guide motor rotates in reverse, they are drivingly connected to the clutch shafts 221a, 221b and rotate together with the clutch shafts 221a, 221b.

[0036] A first forward gear 215a is attached to one end of the first rotating shaft 211a, and a first reverse gear 216a is attached to the other end. A second forward gear 215b is attached to one end of the second rotating shaft 211b, and a second reverse gear 216b is attached to the other end. Each forward gear 215a, 215b meshes with the gear portions of the forward one-way clutches 222a, 222b of the clutch mechanisms 220a, 220b. Each reverse gear 216a, 216b meshes with idler gears 224a, 224b that mesh with the gear portions of the reverse one-way clutches 223a, 223b of the clutch mechanisms 220a, 220b. With such a configuration, the rotation direction of the rotating shaft when the guide motor rotates forward can be made the same as the rotation direction of the rotating shaft when the guide motor rotates in reverse.

[0037] The diameters of the pulleys 213a, 214a, 214b are the same, the diameters of the gear portions of the forward one-way clutches 222a, 222b are the same, and the diameters of the forward gears 215a, 215b are the same. Therefore, the reduction ratios of the drive transmission paths to the rotating shafts 211a, 211b when the guide motor rotates forward are the same. When the guide motor rotates forward, all the guide members 210a, 210b are rotationally driven at the same rotational speed.

[0038] The diameter of the second reverse gear 216b is smaller than the diameter of the first reverse gear 216a, and the reduction ratio of the drive transmission path to the second rotating shaft 211b when the guide motor rotates in reverse is smaller than the reduction ratio of the drive transmission path to the first rotating shaft 211a. Therefore, when the guide motor rotates in reverse, the second guide member 210b rotates at a rotational speed faster than that of the first guide member 210a.

[0039] Further, the diameter of the first reverse gear 216a is smaller than the diameter of the first forward gear 215a, and the diameter of the gear portion of the first reverse one-way clutch 223a is larger than the diameter of the gear portion of the first forward one-way clutch 222a.

[0040] When the guide motor 231 (see FIG. 5) is rotated forward from the first state shown in FIG. 3(a), each of the guide members 210a and 210b rotates at the same rotational speed and can be brought into the second state shown in FIG. 3(b). On the other hand, when the guide motor 231 is rotated reversely from the first state shown in FIG. 3(a), the lowermost second guide member 210b rotates at a rotational speed higher than the rotational speed of the first guide member 210a. As a result, as shown in FIG. 3(c), the second guide member 210b is positioned at the stopper position where the angle with respect to the upper surface of the extension tray 204 is 90°, and the first guide member 210a is in the third state where it is positioned at the guide position where the angle with respect to the upper surface of the extension tray 204 is 30°.

[0041] Also, an electromagnetic clutch is arranged in the drive transmission path from the guide motor 231 to the first timing belt 212a. When returning from the second state or the third state shown in FIG. 3 to the first state, the electromagnetic clutch is turned OFF to disconnect the drive connection with the guide motor so that each of the rotating shafts 211a and 211b can rotate freely. Thereby, due to the self-weight of the guide members and the weight of the loading sheet, each of the guide members 210a and 210b can rotate and return from the second state or the third state shown in FIG. 3 to the first state.

[0042] In this embodiment, the guide driving device 230 is provided to automatically rotate the guide members, but the guide members may be manually rotated without providing the guide driving device 230. In this case, for example, when transporting a sheet that causes sticking during discharge, such as long coated paper, a warning display is made so as to rotate the guide members to the guide position on the operation display unit 102.

[0043] In addition, when arranging three or more guide members, for the guide member at the most downstream in the sheet discharge direction, the second reverse gear 216b is used, and for the other guide members, the first reverse gear 216a is used. Thus, by reversely driving the guide motor, the most downstream guide member can be positioned at the stopper position, and the other guide members can be positioned at the guide position, which is the third state.

[0044] Alternatively, the clutch mechanisms 220a and 220b described above may be changed to electromagnetic clutches, and the second state shown in FIG. 3(b) or the third state shown in FIG. 3(c) may be achieved by ON / OFF control of each electromagnetic clutch. Further, when the clutch mechanisms 220a and 220b described above are changed to electromagnetic clutches, by reversely rotating the guide motor, each guide member can be returned from the guide position to the storage position shown in FIG. 3(a).

[0045] FIG. 5 is a block diagram showing an example of the control system of the image forming system 300 of the present embodiment. The image forming apparatus main body 100 includes a controller 110, a sheet conveyance unit 113 for conveying a sheet, an operation display unit 102, an image forming unit 114 for forming an image on the sheet, a large-capacity paper feeder 101, and an interface unit (I / F) 112 for communicating with a post-processing apparatus, etc.

[0046] The controller 110 is a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The controller 110 controls the entire image forming system 300. The HDD 111 is an auxiliary storage device for storing programs executed by the controller 110 and data used. The HDD 111 may be, for example, a hard disk drive or a storage device composed of a flash memory.

[0047] The operation display unit 102 is a device in which a display device such as a touch panel and an input device are integrated. The input device is a device for a user, an administrator, or the like to perform various input operations. The user inputs the type (basis weight, coated paper, etc.) and size of the sheet set in the high-capacity paper feeder 101 and the type and size of the sheet set in the paper feeding unit of the image forming apparatus main body 100 on the operation display unit 102. The type information and size information of the sheet input to the operation display unit 102 are stored in the HDD 111, which is a non-volatile memory of the image forming apparatus main body 100.

[0048] The high-capacity paper feeder 101 includes a controller 101a that controls a paper feeding device 101c for feeding sheets to the image forming apparatus main body 100, an interface unit (I / F) 112 that communicates with the image forming apparatus main body 100, and the like. The controller 101a of the high-capacity paper feeder 101 is also a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

[0049] The post-processing device 200 includes a controller 250 that controls the devices included in the post-processing device 200, an interface unit (I / F) 112 that communicates with the image forming apparatus main body 100, and the like. The sheet conveyance device 240 is composed of a pair of conveyance rollers, a pair of paper discharge rollers, branch claws T1 to T4, a plurality of motors that drive the pair of conveyance rollers and the pair of discharge rollers, a plurality of motors that drive the branch claws, and the like, which were described with reference to FIG. 2.

[0050] The controller 101a of the post-processing device 200 is also a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like.

[0051] The controller 250 of the post-processing device receives information on the post-processing to be performed on the sheet from the image forming apparatus main body 100, and controls the sheet conveyance device 240 and the post-processing device (stapler SP, intermediate stapler SSP, punch unit PU) based on this post-processing information.

[0052] Also, the controller 250 of the post-processing device receives information on the type and size of the sheet to be conveyed from the image forming apparatus main body 100, and controls the guide motor 231 based on the received information on the type and size of the sheet, so that the guide member of the extension tray 204 is in any one of the states shown in FIGS. 3(a) to 3(c).

[0053] Also, in the present embodiment, the user can specify the state of the guide member on the operation display unit 102. Specifically, by operating the operation display unit 102, as shown in FIG. 6, a "guide state adjustment" image is popped up on the display device of the operation display unit 102. Then, the user can specify any one of the first to third states shown in FIGS. 3(a) to 3(c) by touching the display device or operating the input device. When the user specifies "automatic" in the "guide state adjustment" image, the device automatically sets to any one of the first to third states based on the sheet type information and size information. Also, the user may be able to specify the state of the guide member from application software installed on a personal computer (PC).

[0054] As will be described later, since sticking is unlikely to occur with long sheets that are not coated paper or long sheets of thick paper, in the present embodiment, it is set to the first state. However, depending on the device environment, etc., sticking may occur even with long sheets that are not coated paper or long sheets of thick paper, resulting in paper discharge failure. By enabling the user to specify the state of the guide member as described above, when sticking occurs in the first state, the user can take measures against the problem, such as changing to the second state.

[0055] FIG. 7 is a control flow diagram for setting the state of the guide member based on the type and size information of the sheet. When the controller 250 of the post-processing device receives user-specified information specifying the state of the guide member from the main body 100 of the image forming apparatus (Yes in S1), the controller 250 sets the state of the guide member to the state specified by the user based on the user-specified information.

[0056] On the other hand, when there is no user-specified information (No in S1), the controller 250 of the post-processing device sets the state of the guide member based on the type information and size information of the sheet.

[0057] When the conveyance direction length of the sheet discharged to the lower discharge tray 202 is less than 700 mm and the sheet is not a long sheet (No in S2), the sheet will not reach the extension tray 204. Therefore, at this time, it is set to the first state in which all the guide members shown in FIG. 3(a) are located at the storage positions.

[0058] Also, even when the conveyance direction length of the sheet is 700 mm or more and the sheet is a long sheet, sticking is unlikely to occur for a long sheet that is not coated paper and has low surface smoothness, or a long sheet with a paper thickness exceeding 163 gsm and a thick paper thickness. When it is not coated paper, there are irregularities on the surface, and air easily flows between the discharged sheet and the stacked sheet, making it difficult for the discharged sheet to stick to the stacked sheet. Also, in the case of thick paper, since the stiffness is strong, the leading end side of the sheet discharged from the lower paper discharge roller pair is difficult to bend and shift. Therefore, the leading end of the discharged sheet contacts the stacked sheet at a location away from the lower paper discharge roller pair. Also, even after the leading end of the discharged sheet contacts the discharged sheet, only the leading end portion of the discharged sheet slides on the stacked sheet. Therefore, in the case of thick paper, even if it is a long sheet, the sliding period between the discharged sheet and the stacked sheet does not become long, and the contact area with the stacked sheet is also small. Therefore, a thick long sheet is unlikely to have sticking occur even if it is a sheet with high smoothness such as coated paper. Thus, when the long sheet discharged to the lower discharge tray 202 is not coated paper (No in S3) or is a long sheet with a paper thickness exceeding 163 gsm and a thick paper thickness (No in S4), it is set to the first state.

[0059] Also, when the sheet discharged onto the lower discharge tray 202 is a long coated paper with a length in the sheet conveyance direction of L mm or less (Yes in S3, Yes in S4, Yes in S5), the second guide member 210b is set to a third state where it is positioned at the stopper position and the first guide member 210a is positioned at the guide position (see Fig. 3(c)). Note that the above L mm is the maximum length in the conveyance direction such that when discharged onto the lower discharge tray, the leading edge of the sheet does not reach the second guide member (the length in the sheet conveyance direction from the upstream end in the sheet discharge direction of the lower discharge tray to the second guide member). Thus, when the length in the sheet conveyance direction is L mm or less, the second guide member can be used as a stopper, and the fall of the sheet from the extension tray 204 can be suppressed.

[0060] On the other hand, when the long coated paper has a length in the sheet conveyance direction exceeding L mm (Yes in S3, Yes in S4, No in S5), all the guide members are set to the second state shown in Fig. 3(b) where they are positioned at the guide positions. Thereby, sticking of the discharged sheet to the stacked sheets can be well suppressed, and the occurrence of discharge defects can be suppressed.

[0061] Also, when the length in the sheet conveyance direction exceeds L mm, the number of sheets that can be stacked is reduced from the perspective of the strength of the lower discharge tray 202. This is because the greater the length of the sheet, the greater the sheet weight.

[0062] In the case of coated paper with a basis weight of about 157 - 163 gsm, it has relatively high stiffness, is less likely to sag from the tip of the guide member 210a, and when the number of stacked sheets increases, the inclination of the upper surface of the stacked sheet bundle from the tip of the guide member 210a becomes gentle. As a result, as shown in Fig. 8(b), the position where it jumps out from the tip of the guide member, draws a parabola, and then falls and re - contacts the stacked sheet is upstream in the discharge direction compared to the re - contact position X1 when the number of stacked sheets is small in Fig. 8(a).

[0063] As a result, the discharge sheet separated from the loading sheet immediately comes into contact with the loading sheet. Therefore, the reduction of the sliding period and the contact area with the loading sheet becomes insufficient, sticking occurs, and the loading sheet stuck to the discharge sheet may be pushed downstream in the discharge direction by the conveying force of the discharge sheet. As a result, the stuck loading sheet may fall from the downstream end of the extension tray 204 in the discharge direction.

[0064] When the length of the sheet in the conveyance direction exceeds L mm, in order to reduce the number of sheets that can be loaded from the viewpoint of the strength of the lower discharge tray 202, the number of sheets that can be loaded is reached before the number of sheets that cause sticking occurs. Therefore, when the length L mm of the sheet in the conveyance direction is exceeded, sticking to the discharge sheet due to an increase in the number of loading sheets can be suppressed well. Therefore, even in the second state, sheet dropping can be suppressed.

[0065] On the other hand, when the length of the sheet in the conveyance direction is L mm or less, since the number of sheets that can be loaded is large, sticking is likely to occur when the number of loading sheets increases. Therefore, there is a possibility that the loading sheet may fall from the extension tray due to being pushed downstream in the discharge direction by the discharge sheet of the loading sheet. However, in the present embodiment, when the length of the sheet in the conveyance direction is L mm or less, in order to position the second guide member at the stopper position as the third state, when the number of sheets that can be loaded increases, when the discharge sheet sticks to the loading sheet and is pushed downstream in the discharge direction, it can be stopped by the second guide member. Thereby, it is possible to prevent the sheet from falling from the downstream end of the extension tray in the discharge direction.

[0066] FIG. 9 is a control flowchart of the rotation operation of the guide member. When the controller 250 of the post-processing device receives a job from the image forming apparatus main body 100 (S11), it checks the setting of the state of the guide member set in the control flow shown in FIG. 7 (S12). When the state setting of the guide member is in the first state, the rotation of the guide member is not performed and the job is started (S17).

[0067] On the other hand, when the setting is in the second state or the third state, perform the rotation operation of the guide member to set it to the second state shown in Fig. 3(b) or the third state shown in Fig. 3(c) (S13). When the setting is in the second state, drive the guide motor 231 forward for a predetermined time. When the setting is in the third state, drive the guide motor 231 backward for a predetermined time. Then, when it reaches the second state or the third state, start the job (S14).

[0068] When the job is completed (S15), turn off the electromagnetic clutch, disconnect the drive connection between each guide member and the guide motor, and make each guide member rotatable freely. As a result, due to the self-weight of the guide member and the weight of the loading sheet, the guide member rotates, and all the guide members shown in Fig. 3(a) are in the first state where they are located at the storage position.

[0069] If left in the second state or the third state after the job is completed, the loading sheet may develop wavy marks. Therefore, by setting it to the first state after the job is completed, it is possible to prevent the loading sheet from developing marks.

[0070] In the second state, it is possible to change the inclination angle of the guide member according to the driving time of the guide motor 231. As the number of loading sheets increases, as described with reference to Fig. 8, after the guide member separates from the loading sheet, the position where it contacts the loading sheet again becomes closer to the guide member, and sticking is likely to occur. In the above description, when the length L mm in the sheet conveyance direction exceeds, the maximum number of sheets that can be loaded is reached before the number of sheets at which sticking occurs. However, depending on the strength of the lower discharge tray 202, the maximum number of sheets that can be loaded when the length L mm in the sheet conveyance direction exceeds may be set to be equal to or more than the number of sheets at which sticking is likely to occur. In such a case, based on the number of loading sheets loaded on the extension tray 204, the inclination angle of each guide member (the angle formed between the upper surface of the extension tray and the guide member) in the second state may be changed to suppress sticking.

[0071] FIG. 10 is a control flowchart for adjusting the tilt angle of each guide member in the second state according to the number of stacked sheets. When the job is started in the second state, the controller 250 of the post-processing device counts the number of sheets discharged to the lower discharge tray 202 (extended tray 204) (S21). If the number of discharged sheets exceeds the threshold (Yes in S22), the guide motor 231 is driven forward to increase the tilt angle (S23). As a result, the sag from the tip of the guide member on the upper surface of the stacked sheet bundle can be increased suddenly, and it is possible to suppress the contact position of the discharged sheet that contacts the stacked sheet again after protruding from the tip of the guide member from getting too close to the guide member. Thereby, the occurrence of sticking when the number of stacked sheets is large can be suppressed.

[0072] When the tilt angle of the guide member is changed, the discharge sheet count value is reset (S24). Again, if the number of discharged sheets exceeds the threshold, the tilt angle of the guide member is increased by a predetermined angle again. Note that if the tilt angle of the guide member is too large, the horizontal vector component when the discharged sheet jumps out of the guide member decreases, and the discharged sheet falls near the guide member. Therefore, the tilt angle is preferably limited to around 45°.

[0073] Also, the optimal tilt angle of the guide member at which the tip of the discharged sheet protruding from the tip of the guide member contacts the stacked sheet at the farthest position varies depending on the stiffness of the sheet. Therefore, in the second state, the tilt angle of the guide member may be changed based on the stiffness of the sheet (paper thickness (basis weight)). Thereby, the long sheet can be discharged more stably.

[0074] Also, by changing the clutch mechanisms 220a and 220b to electromagnetic clutches, even in the third state of FIG. 3(c), the tilt angle at the guide position of the first guide member can be changed based on sheet stiffness information such as sheet thickness and the number of stacked sheets. Also, by using electromagnetic clutches, the tilt angle at the guide position of the first guide member 210a and the tilt angle at the guide position of the second guide member 210b in the second state can be made different from each other.

[0075] Further, by using an electromagnetic clutch, in a configuration using three or more guide members, the following state can be achieved. That is, according to the length of the long sheet in the sheet conveyance direction, the guide members other than the lowermost stream are positioned at the stopper positions. And, the guide members on the downstream side of the guide members positioned at the stopper positions and the guide members on the upstream side of the guide members positioned at the stopper positions are in a state of being positioned at the guide positions.

[0076] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims, unless otherwise particularly limited in the above description.

[0077] For example, in the above description, the present invention is applied to the extension tray which is the discharge tray of the post-processing device, but the present invention may also be applied to the discharge tray of the image forming apparatus and the original discharge tray of the ADF.

[0078] What has been described above is an example, and specific effects are achieved for each of the following aspects. (Aspect 1) In a discharging device having a discharging tray such as the extension tray 204 from which a sheet is discharged, a plurality of guide members 210a and 210b that are inclined with respect to a sheet placement portion such as the upper surface of the discharging tray and guide the sheet being discharged are arranged at a predetermined interval in the sheet discharging direction. In the case of a long sheet, the contact period with the sheet on the discharging tray (hereinafter referred to as the stacked sheet) is long, and the contact area with the stacked sheet is large. Therefore, when the long sheet is a sheet having high surface smoothness such as coated paper that is likely to stick, the sheet being discharged (hereinafter referred to as the discharged sheet) may stick to the stacked sheet. If the discharged sheet sticks to the stacked sheet on the discharging tray, the discharge is stopped by the stuck stacked sheet, and rear-end residue or buckling may occur, or the stuck stacked sheet may move together with the discharged sheet, and the stacked sheet may fall from the discharging tray, resulting in poor sheet discharge. In contrast, in Embodiment 1, the discharge sheet is guided in a direction away from the sheet placement portion of the discharge tray by a guide member that is inclined with respect to the sheet placement portion of the discharge tray. In this way, when the discharge sheet is guided by the guide member, the discharge sheet behaves as follows. That is, the portion of the stacked sheet facing the guide member is lifted by the guide member and bends downward from the tip (top) of the guide member. On the other hand, the discharge sheet that has been guided by the guide member jumps out from the tip of the guide member in the guide direction of the guide member by the conveying force. As a result, the discharge sheet separates from the stacked sheet. Thereafter, the discharge sheet falls while tracing a parabola and contacts the stacked sheet again, but between the tip of the guide member and the re-contact portion of the discharge sheet, it behaves as if it floats up and separates from the stacked sheet. And in Embodiment 1, since a plurality of guide members are arranged at a predetermined interval in the sheet discharge direction, when the discharge sheet is a long sheet, the above-described behavior is performed multiple times. Thereby, it is possible to prevent the contact period with the stacked sheet from becoming long and to reduce the contact area with the stacked sheet. As a result, even if the long sheet is a sheet with high surface smoothness, it is possible to satisfactorily suppress sticking to the stacked sheet, and it is possible to suppress sheet discharge defects such as remaining at the rear end, buckling, and dropping of the stacked sheet.

[0079] (Embodiment 2) In Embodiment 1, each of the guide members 210a, 210b is rotatably supported by a discharge tray such as the extension tray 204, and control means such as a controller 250 that controls the rotation of the plurality of guide members is provided so that the guide member can take any one of a storage position housed in the discharge tray, a guide position inclined with respect to the sheet placement portion, and a stopper position perpendicular to the sheet placement portion. According to this, as described in the embodiment, by positioning the guide member at the guide position, the long coated paper can be guided to separate the discharged sheet from the stacked sheet, suppressing the occurrence of sticking. Also, by positioning the guide member at the stopper position, the movement of the sheet in the discharge direction can be restricted by the guide member, suppressing the sheet from falling from the discharge tray. Further, after the job is completed, the guide member can be positioned at the storage position, suppressing the formation of wrinkles such as undulations on the sheet on the discharge tray.

[0080] (Aspect 3) In Aspect 2, control means such as the controller 250 controls the rotation of the plurality of guide members based on at least one of the information of the sheet to be discharged and the number of sheets discharged to the discharge tray. According to this, as described in the embodiment, when it is determined from the sheet information that the sheet to be discharged to the discharge tray is a sheet that is likely to stick, such as a long coated paper and not a cardboard, the guide member can be positioned at the guide position to suppress the occurrence of sticking. Also, when the leading edge of the sheet does not reach the position of the guide member at the most downstream in the sheet discharge direction from the discharge direction length of the sheet discharged as sheet information, the guide member at the most downstream can be positioned at the guide position to stop the discharged sheet. Further, as described with reference to FIG. 10, the inclination angle of the guide member positioned at the guide position can be changed according to the number of sheets discharged to the discharge tray. Thereby, even when the number of stacked sheets on the discharge tray increases, the sticking of the discharged sheet to the stacked sheet can be favorably suppressed.

[0081] (Aspect 4) In Aspect 3, control means such as the controller 250 controls the rotation of the plurality of guide members so that all the guide members can take any one of a first state in which they are positioned at the storage position, a second state in which all the guide members are positioned at the guide position, and a third state in which the guide member at the most downstream in the sheet discharge direction is positioned at the stopper position and the other guide members are positioned at the guide position. According to this, as described with reference to FIGS. 7 and 9, when it is determined from the sheet information that the sheet to be discharged onto the discharge tray is a sheet that may cause sticking, such as a long coated paper that is not cardboard, by setting it to the second state or the third state, sticking can be suppressed.

[0082] (Aspect 5) In Aspect 4, it includes a drive motor such as a guide motor 231 that is controlled by control means such as a controller 250 and rotates all guide members. When the drive motor rotates forward, it switches from the first state to the second state, and when the drive motor rotates backward, it switches from the first state to the third state. It has a drive transmission mechanism that transmits the driving force of the drive motor to each guide member. According to this, as described with reference to FIG. 4, it is possible to switch from the first state to the second state and from the first state to the third state by one drive motor.

[0083] (Aspect 6) In Aspect 4 or 5, the control means such as the controller 250 controls the rotation of the plurality of guide members based on the user's instruction when there is a user's instruction. According to this, as described with reference to FIG. 7, when a discharge failure due to sticking occurs, it is possible to perform discharge by setting it to the second state or the third state according to the user's instruction, and the user can handle the discharge failure due to sticking.

[0084] (Aspect 7) In any one of Aspects 3 to 6, the control means such as the controller 250 changes the inclination angle of the guide member located at the guide position with respect to the sheet placement portion based on the number of sheets of the sheet discharged onto the discharge tray. According to this, as described with reference to FIG. 10, even when the number of stacked sheets on the discharge tray increases, it is possible to satisfactorily suppress discharge failures due to sticking.

[0085] (Aspect 8) In any of Aspects 2 to 7, when all the sheets on which a predetermined process has been performed have been discharged, control means such as the controller 250 controls the rotation of the plurality of guide members so that all the guide members are positioned at the storage position. According to this, as described in the embodiment, it is possible to suppress the long-term storage of the sheet lifted by the guide member, and it is possible to suppress the formation of wrinkles such as undulations in the stacked sheets on the discharge tray.

[0086] (Aspect 9) In an image forming apparatus including image forming means such as an image forming unit that forms an image on a sheet, and a discharge device that discharges the sheet on which the image has been formed, as the discharge device, the discharge device according to any of Aspects 1 to 8 is used. According to this, it is possible to suppress the occurrence of discharge defects when an image is formed on a long coated paper and discharged onto the discharge tray.

[0087] (Aspect 10) In a post-processing apparatus including post-processing means for performing a predetermined post-processing on a sheet on which an image has been formed, and a discharge device that discharges the sheet on which the predetermined post-processing has been performed, as the discharge device, the discharge device according to any of Aspects 1 to 8 is used. According to this, it is possible to suppress the occurrence of discharge defects when an image is formed on a long coated paper and discharged onto the discharge tray.

Explanation of Reference Numerals

[0088] 100: Image forming apparatus main body 101: High-capacity paper feeder 102: Operation display unit 200: Post-processing apparatus 201: Upper discharge tray 202: Lower discharge tray 203: Intermediate binding tray 204: Extension tray 210a: First guide member 210b: Second guide member 211a: First rotation shaft 211b: Second rotation shaft 212a: First timing belt 212b: Second timing belt 213a: First output pulley 213b: Second output pulley 214b: Second input pulley 215a: First forward gear 215b: Second forward gear 216a: First reverse gear 216b: Second reverse gear 220a: First clutch mechanism 220b: Second clutch mechanism 221a: Clutch shaft 221b: Clutch shaft 222a: First forward one-way clutch 222b: Second forward one-way clutch 223a: First reverse one-way clutch 223b: Second reverse one-way clutch 224a: Idler gear 224b: Idler gear 230: Guide drive device 231: Guide motor 250: Controller 300: Image forming system

Prior art documents

Patent documents

[0089]

Patent Document 1

Claims

1. In a discharge device having a discharge tray onto which a sheet is discharged, a sheet ejection device including a plurality of guide members arranged at predetermined intervals in a sheet ejection direction, the guide members being inclined with respect to a sheet placement portion of the ejection tray and guiding the sheet being ejected;

2. 2. The ejection device according to claim 1, Each guide member is rotatably supported by the discharge tray, An ejection device characterized by having a control means for controlling the rotation of multiple guide members so that the guide members can take any of the following positions: a storage position within the ejection tray, a guide position inclined with respect to the sheet loading section, or a stopper position perpendicular to the sheet loading section.

3. 3. The discharge device according to claim 2, The discharge device, wherein the control means controls rotation of a plurality of guide members based on at least one of information on the sheets to be discharged and information on the number of sheets discharged onto the discharge tray.

4. 4. The discharge device according to claim 3, The control means controls the rotation of multiple guide members based on information about the sheets to be discharged so that the device can take one of three states: a first state in which all guide members are positioned at the storage position, a second state in which all guide members are positioned at the guide position, or a third state in which the guide member most downstream in the sheet discharge direction is positioned at the stopper position and the other guide members are positioned at the guide positions.

5. 5. The discharge device according to claim 4, a drive motor controlled by the control means for rotating all of the guide members; a drive transmission mechanism that transmits the driving force of the drive motor to each guide member so that when the drive motor is rotated forward, the state is switched from the first state to the second state, and when the drive motor is rotated reversely, the state is switched from the first state to the third state.

6. 5. The discharge device according to claim 4, The discharge device, wherein the control means controls the rotation of a plurality of guide members based on a user instruction when the user instructs the control means.

7. 4. The discharge device according to claim 3, The discharge device according to claim 1, wherein the control means changes an inclination angle of a guide member located at the guide position with respect to the sheet placement portion based on information on the number of sheets discharged onto the discharge tray.

8. 3. The discharge device according to claim 2, The discharge device is characterized in that the control means controls the rotation of the plurality of guide members so that all of the guide members are positioned at the storage position when all of the sheets that have been subjected to a predetermined process have been discharged.

9. an image forming means for forming an image on a sheet; and a discharge device to which a sheet having an image formed thereon is discharged, 2. An image forming apparatus, comprising the discharge device according to claim 1 as said discharge device.

10. a post-processing unit for performing a predetermined post-processing on the sheet on which the image is formed; a discharge device to which a sheet having been subjected to a predetermined post-processing is discharged, A post-processing device, comprising the discharge device according to claim 1 as the discharge device.

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