Ejection device and imaging device

Abstract

An ejection device includes an alignment unit for aligning a stack of sheets as a sheet bundle, an ejection unit for ejecting the sheet bundle, an ejection tray on which the sheet bundle ejected by the ejection unit is stacked, and a support unit. The support unit supports the sheet bundle from below by extending in a sheet ejection direction of the sheet bundle when the sheet bundle is ejected to the ejection tray, and is accommodated in a direction opposite to the sheet ejection direction when the ejection unit finishes ejecting the sheet bundle.

Description

TECHNICAL FIELD

[0001] The present application relates to an ejection device that ejects a recording medium sheet onto an ejection tray and an image forming apparatus equipped with the ejection device. BACKGROUND

[0002] An ejection device is known that captures a recording medium sheet, holds the sheet in a stack, aligns the stacked sheet, sorts the sheet, performs an image forming post-process such as stapling, folding, bundling, and the like on the sheet, and then ejects the stacked sheet onto a sheet accumulation tray that extends outward from the ejection device.

[0003] Sheet processing devices are disclosed in Japanese Patent No. 4694401 and Japanese Laid-Open Patent Application No. 2017-43476 that use a pair of rollers facing each other to eject a recording medium sheet, and input a driving force to each of the rollers in order to satisfactorily convey the sheet.

[0004] However, each of the ejection devices disclosed in Japanese Patent No. 4694401 and Japanese Laid-Open Patent Application No. 2017-43476 uses a sheet accumulation tray and / or a top surface of an uppermost sheet of the stacked recording medium sheets on the sheet accumulation tray to accumulate the recording medium sheets, align the sheets, and eject the sheets. Therefore, it cannot prevent the problem that the recording medium sheet rubs the top surface of the uppermost sheet of the stacked sheets on the sheet accumulation tray when the recording medium sheet is ejected from the ejection device. In particular, they encounter the problem that the bottom surface of the sheet being ejected rubs the top surface of the uppermost sheet of the stacked sheets in the sheet accumulation tray when the recording medium sheet is ejected from the image forming apparatus in a double-sided mode, and thus the image is damaged. Moreover, the ejection devices disclosed in Japanese Patent No. 4694401 and Japanese Laid-Open Patent Application No. 2017-43476 have to control the position of the top surface of the uppermost sheet of the stacked recording medium sheets in the sheet accumulation tray in the vertical direction. Therefore, the sheet accumulation tray is required to be able to move upward or downward quickly. Therefore, they need a large driving motor to meet this requirement.

[0005] In contrast, Japanese Laid-Open Patent Application No. 2011-46534 discloses a sheet processing device in which a swing paper knock that is in the form of a comb is located on the downstream side of the above-mentioned pair of ejection rollers in order to align the sheet and hold the stacked sheet in the sheet accumulation tray, separate from the sheet being ejected, while supporting the sheet.

[0006] However, the structure of the sheet processing device disclosed in Japanese Laid-Open Patent Application No. 2011-46534 causes the swing paper ejector to project on the top side of the stacked sheets on the sheet accumulation tray, which is located outside the discharge device. Therefore, it is problematic in terms of usability. For example, it is difficult to take out the sheets from the sheet accumulation tray. SUMMARY

[0007] An object of the present application is to provide a discharge device that enables the recording medium sheets on its discharge tray to be easily taken out from the tray, and an image forming apparatus equipped with such a discharge device.

[0008] According to one aspect of the present application, there is provided: an alignment unit on which a stack of supplied sheets is stacked, the alignment unit being provided to align the stacked sheets into a sheet bundle; a discharge unit for discharging the sheet bundle of the sheets aligned by the alignment unit; a discharge tray on which the stack of sheets discharged by the discharge unit is stacked; and a support unit provided to support the sheet bundle from below by extending in a sheet discharge direction of the sheet bundle when the sheet bundle is discharged onto the discharge tray by the discharge unit, and to be accommodated in a direction opposite to the sheet discharge direction when the discharge unit ends discharging the sheet bundle.

[0009] Other features of the present application will become clear from the following description of example embodiments (with reference to the attached drawings). BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a schematic view of an image forming apparatus in a first embodiment of the present application.

[0011] Figure 2 Parts (a) and (b) of are a top perspective view of a sheet bundle discharge unit of a discharge device in the first embodiment of the present application, and an enlarged bottom view of a portion of the same discharge unit.

[0012] Figure 3 Parts (a) and (b) of are a top perspective view of a sheet bundle discharge unit of a discharge device in the first embodiment of the present application, and an enlarged view of a portion of the same discharge unit.

[0013] Figure 4 is an enlarged view of a portion of a sheet bundle discharge unit of a discharge device in the first embodiment of the present application (seen in the direction of the arrow mark in Figure 2 ).

[0014] Figure 5 Parts (a) and (b) of are a perspective view of a bottom unit of a discharge device in the first embodiment of the present application.

[0015] Figure 6 is a perspective view of a support plate of a bottom unit of the discharge device in the first embodiment of the present application.

[0016] Figure 7 Parts (a), (b), (c) and (d) of FIG. 1 are schematic diagrams for showing the operation of the discharge device in the first embodiment of the present application.

[0017] Figure 8 is a timing chart of the discharge device in the first embodiment of the present application.

[0018] Figure 9 Parts (a), (b), (c) and (d) of FIG. 2 are schematic diagrams for showing the operation of the front half of the discharge device in the first embodiment of the present application.

[0019] Figure 10 Parts (a), (b), (c) and (d) of FIG. 3 are schematic diagrams for showing the operation of the rear half of the discharge device in the first embodiment of the present application.

[0020] Figure 11 is an enlarged view of a part of the discharge device in the second embodiment of the present application. DETAILED DESCRIPTION

[0021] The structure of some preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0022] (Embodiment 1)

[0023] <Structure of Image Forming Device>

[0024] First, the structure of the image forming device 100 in the first embodiment of the present application will be described in detail. Figure 1

[0025] The image forming device 100 has an image forming unit 1, an image reading unit 2, a document supply unit 3 and a discharge device 4.

[0026] The image forming unit 1, which is an image forming section, reads a document using its image reading unit, develops and adjusts the data of the read image using a controller not shown, and forms an image of the read image on a recording medium sheet. The image forming unit 1 conveys the sheet on which the image has just been formed to the discharge device 4. Incidentally, the details of the structure of the image forming unit 1 will be described later.

[0027] ​The image reading unit 2 has an image reading section 16 which reads the surface of the document facing it, a driving device 17 which moves the image reading section 16 back and forth, and an image reading section 19 which reads the surface of the document facing it. The image reading unit 2 outputs the image information read by the image reading sections 16 and / or 19 to the not-shown controller of the image forming unit 1.

[0028] The image reading unit 2 can read both surfaces of the document using the image reading sections 16 and 19 at the same time. Therefore, both surfaces of the document can be read by passing the document through the image reading unit 2 once. The structure of the image reading unit 2 enables the image reading section 16 to reciprocally scan the document by reciprocally moving the image reading section 16 (by using the driving device 17), so that the document (e.g., a booklet) which cannot be handled by the document feeding unit 3 can be read.

[0029] The document feeding unit 3 has a document placement tray 18 in which a document is placed, and a document capturing section 20 into which a document is discharged. The document feeding unit 3 conveys the document in the document placement tray 18 to the image reading sections 16 and 19 of the image reading unit 2. When the document is conveyed by the image reading unit 2, the document is discharged into the document capturing section 20 of the document feeding unit 3.

[0030] When a preset number of pieces of recording medium sheet are conveyed from the image forming unit 1 to the discharging device 4, the discharging device 4 processes (post-processes) them and discharges them. Incidentally, the structure of the discharging device 4 will be described later in detail.

[0031] <Structure of image forming unit>

[0032] The image forming device 100 of the first embodiment of the present application will be described below with reference to Figure 1 The image forming unit 1 of the image forming device 100 in the first embodiment of the present application will be described in detail.

[0033] The image forming unit 1 has a sheet feeding section 6, a pair of alignment rollers 7, an image forming cartridge 8, a photosensitive drum 9, a transfer roller 10, and a fixing unit 11. Further, the image forming unit 1 has a pair of reversal rollers 12, a re-feeding section 13, a horizontal conveying section 14, and a laser scanner unit 15.

[0034] The image forming unit 1 is provided with a plurality of sheet feeding sections 6. Each sheet feeding section 6 can hold a plurality of pieces of recording medium sheet. The sheet feeding section can feed the sheets therein to the pair of alignment rollers 7 one by one at a preset interval.

[0035] When the sheet is inclined to arrive, the pair of alignment rollers 7 collimate the recording medium sheet as it is conveyed from the sheet feeding portion 6 or the re-feeding portion 13 to the pair of alignment rollers 7. Then, they convey the sheet to the image forming cartridge 8.

[0036] The image forming cartridge 8 forms an image on the recording medium sheet conveyed from the sheet feeding portion 6 or the re-feeding portion 13 to the image forming cartridge 8. Then, the sheet cartridge conveys the sheet on which the image is formed to the fixing unit 11. The image forming cartridge 8 has a photosensitive drum 9 and a transfer roller 10.

[0037] The photosensitive drum 9 is rotatably supported in the image forming cartridge 8. A toner image is formed on the photosensitive drum 9 through exposure, charging, latent image formation, and development processes. When the recording medium sheet is conveyed to the photosensitive drum 9 by the pair of alignment rollers 7, the photosensitive drum 9 conveys the sheet to the fixing unit 11 while the sheet is held between the photosensitive drum itself and the transfer roller 10.

[0038] The transfer roller 10 is provided with a preset amount of electric charge. When the sheet is conveyed to the transfer roller 10 by the pair of alignment rollers 7, the transfer roller 10 transfers the toner image on the photosensitive drum 9 to the recording medium sheet.

[0039] When the recording medium sheet on which the toner image is carried is conveyed to the fixing unit 11, the fixing unit 11 fixes the toner on the sheet to the sheet by heating the toner while pressing the toner. After fixing the toner to the sheet, the fixing unit 11 conveys the sheet to the horizontal conveying portion 14.

[0040] In the case where an image is to be printed on both surfaces of the recording medium sheet, when the trailing end of the sheet reaches the nip of the pair of reversing rollers 12, the pair of reversing rollers 12 changes the direction of rotation to change the conveying direction of the sheet (conveyed backward) to convey the sheet to the re-feeding portion 13.

[0041] When the recording medium sheet is conveyed to the re-feeding portion 13 by the pair of reversing rollers 12, the re-feeding portion 13 conveys the recording medium sheet to the pair of alignment rollers 7.

[0042] When the recording medium sheet is conveyed to the horizontal conveying portion 14 by the fixing unit 11, the horizontal conveying portion 14 conveys the sheet to the pair of entry rollers 21 of the discharge device 4 by being driven by a driving portion not shown. The horizontal conveying portion 14 is provided with an internal one-way clutch not shown, which allows the conveying roller of the horizontal conveying portion 14 to slip when it pulls the recording medium sheet in the same direction as the conveying direction of the sheet (hereinafter, simply referred to as "conveying direction").

[0043] By moving the laser beam in a direction perpendicular to the sheet transport direction to scan the outer peripheral surface of the photosensitive drum 9 (using its polygonal reflector and lens), the laser scanner unit 15 forms a latent image on the photosensitive drum 9.

[0044] <Structure of the discharge device>

[0045] The following will refer to Figure 1 The structure of the discharge device 4 of the image reading device 100 in the first embodiment of the present invention will be described in detail.

[0046] The discharge device 4 operates under the control of a control unit (not shown). The discharge device 4 includes a pair of inlet rollers 21, a pair of pre-buffer rollers 22, a pair of reverse rollers 24, a sheet capture top tray 25, a pair of inner discharge rollers 26, an inlet sensor 27, a pair of intermediate conveyor rollers 28, and a pair of kick-out rollers 29. Furthermore, the discharge device includes a sheet stack pressing mark 30, a crescent-shaped roller 33, a sheet stack discharge guide 34, a guide drive section 35, a sheet stack discharge unit 36, a bottom discharge tray 37, a pre-stack sensor 38, a sheet stack intermediate section 39, and a sheet pressing guide 56.

[0047] When the recording medium sheet is conveyed to a pair of inlet rollers 21 via the horizontal conveyor section 14, the pair of inlet rollers convey the sheet to the pair of pre-buffer rollers 22.

[0048] The pair of pre-buffered rollers 22 transfer the recording medium sheet, which is fed to them by a pair of infeed rollers 21, to a pair of reverse rollers 24 at a preset time, while accelerating the sheet.

[0049] When the recording medium sheet is to be discharged into the top discharge tray 25, the reverse roller 24 discharges the sheet into the top discharge tray 25 as the sheet is conveyed to the pre-buffer roller 22. When the recording medium sheet is to be discharged into the bottom discharge tray 37, the reverse roller 24 temporarily holds the sheet as the rear end of the sheet moves along the sheet conveying direction past the reverse flow prevention valve 23, which is held by a spring (not shown). Figure 1 The sheet is pressed clockwise. Then, the reverse roller 24 conveys the temporarily held sheet backward to the inner discharge roller 26. Then, when the leading edge of the sheet reaches the inner discharge roller 26 along the sheet conveying direction, the reverse rollers 24 separate from each other to accommodate the next recording medium sheet.

[0050] The reversing roller 24 functions as a buffer by layering a subsequent sheet (that is, a recording medium sheet conveyed by the pre-buffering roller 22) on a previous sheet (that is, a sheet conveyed backward by the inner discharge roller 26). The sheet buffering enables buffering of a predetermined number of sheets (regardless of the sheet length) by repeatedly conveying the inner discharge roller 26 backward (backward operation). Incidentally, the operation of the sheet buffering will be described in detail later.

[0051] When the recording medium sheets are continuously discharged into the top discharge tray 25, the sheets are layered in the top discharge tray 25. When the sheets are layered in the top discharge tray 25, the top discharge tray 25 moves the sheets in the direction indicated by an arrow mark A2 in accordance with the top surface position of the top sheet in the top discharge tray 25 detected by a sheet surface position detecting sensor not shown and in accordance with the number of layered sheets in the top discharge tray 25. Also, when it is detected that the layered sheets in the top discharge tray 25 have been taken out, the top discharge tray 25 moves in the direction indicated by an arrow mark Al. In other words, the top discharge tray 25 maintains the top surface of the top sheet in the top discharge tray 25 at a predetermined level regardless of the number of sheets therein. Figure 1

[0052] When the inner discharge roller 26 holds the recording medium sheet conveyed to it by the reversing roller 24, the driving of the inner discharge roller 26 is temporarily stopped. Then, at the same timing as that at which the subsequent sheet passes, the sheet is started to be conveyed backward to the reversing roller 24. Then, when the sheet reaches the inner discharge roller 26, the inner discharge roller 26 conveys the sheet to the intermediate conveying roller 28.

[0053] When the entry sensor 27 detects the recording medium sheet, it outputs the detection result to a control portion not shown.

[0054] When the recording medium sheet passes through the inner discharge roller 26 to be conveyed to the intermediate conveying roller 28, the intermediate conveying roller 28 conveys the sheet to a pair of kick-out rollers 29.

[0055] When the recording medium sheet passes through the intermediate conveying roller 28 to be conveyed to the kick-out roller 29, the kick-out roller 29 conveys the sheet to the sheet layering intermediate portion 39.

[0056] The sheet stack pressing mark 30 is rotatably positioned on the downstream side of the kick-out roller 29 in the conveying direction. It prevents the rear end (in the sheet conveying direction) of each layered recording medium sheet in the sheet layering intermediate portion 39 from being bent upward so as to prevent interference of the rear end with the front end (in the sheet conveying direction) of a sheet conveyed subsequently to the sheet layering intermediate portion 39.

[0057] ​The half-moon shaped roller 33 is rotatably supported by the sheet stacking intermediate portion 31 on the downstream side of the press guide 56 in the conveyance direction. After the record medium sheet passes the pre-stacking sensor 38 on the trailing end in the sheet conveyance direction, it conveys the record medium sheet toward the leading end in the conveyance direction along the vertical alignment reference plate 39a of the sheet stacking intermediate portion 39 according to a pre-set timing. After the sheet passes the kick-out roller 29, it presses the record medium sheet against the vertical alignment reference 39a. The conveyance pressure is adjusted so that it slides on the sheet after it is placed in contact with the vertical alignment reference plate 39a.

[0058] When the guide driving portion 35 is driven, the sheet stack guide 34 moves from its standby position parallel to the sheet stacking intermediate portion 39 toward the sheet stack discharge unit 36 so as to push the stacked sheet stack in the sheet stacking intermediate portion 39.

[0059] When the sheet stack reaches the leading end in the sheet stack press direction to the sheet stack discharge unit 36, the driving of the guide driving portion 35 is stopped so as to stop the sheet stack discharge guide 34. Then, the guide driving portion 35 is driven again so that the sheet stack discharge guide 34 returns to its standby position.

[0060] The guide driving portion 35 is associated with the sheet stack discharge guide 34. It operates under the control of the above-mentioned control portion.

[0061] The sheet stack discharge unit 36 discharges each record medium sheet stack into (or on) the bottom discharge tray 37 as the sheet stack is pushed out by the sheet stack discharge guide 34. Incidentally, the structure of the sheet stack discharge unit 36 will be described in detail later.

[0062] The bottom discharge tray 37 captures each record medium sheet stack in such a manner that when each stack is discharged by the sheet stack discharge unit 36, the stack is placed on the preceding stack in the bottom discharge tray 37. Based on the position of the top surface of the uppermost stacked sheet detected by a sheet surface sensor not shown, it moves in the direction indicated by the arrow mark B2 in response to the number of stacked sheets therein. Also, when it is detected that the stacked sheets have been taken out, the bottom discharge tray 37 moves in the direction B1 in Figure 1 Thus, the bottom discharge tray 37 maintains the top surface of the uppermost stacked sheet at a pre-set level regardless of the number of stacked sheets therein. Figure 1

[0063] When the intermediate stacking pre-sensor 38 detects the record medium sheet, it outputs the detection result to the control portion not shown.

[0064] ​The sheet-stacking intermediate portion 39, which is an alignment portion, is provided with a vertical alignment reference plate 39a at the front end in the conveyance direction of the sheet-stacking intermediate portion 39. When a recording medium sheet is conveyed to the sheet-stacking intermediate portion 39, the sheet-stacking intermediate portion 39 not only captures the sheet in such a manner that the sheet will be stacked on the previous sheet, but also aligns the sheet by making the front end of the sheet in the sheet conveyance direction hit against the vertical alignment reference plate 39a. The sheet-stacking intermediate portion 39 is provided with a top guide 31 and a bottom guide 32, and the press guide 56 is firmly attached to the top guide 31.

[0065] The press guide 56 is flexible. By applying a predetermined amount of pressure, it maintains contact with the uppermost recording medium stack sheet in the sheet-stacking intermediate portion 39.

[0066] A control portion, not shown, controls the operation of the discharge device 4 on the basis of the detection results input from the entry sensor 27, the pre-sensor 38, and the like.

[0067] <Structure of sheet stack discharge unit>

[0068] The structure of the sheet stack discharge unit 36 of the discharge device 4 in the first embodiment of the present application will be described below with reference to Figures 2-3 The structure of the sheet stack discharge unit 36 of the discharge device 4 in the first embodiment of the present application will be described below with reference to

[0069] Figure 2 Part (a) of FIG. 10 is a perspective view of the entire sheet stack discharge unit 36. Figure 2 Part (b) of FIG. 10 is a perspective view of a portion of the sheet stack discharge unit 36. Figure 2 Part (a) of FIG. 10 is a perspective view of the entire sheet stack discharge unit 36. Figure 2 Part (b) of FIG. 10 is a perspective view of a portion of the sheet stack discharge unit 36. Figure 2 Part (b) of FIG. 10 shows the state of the sheet stack discharge unit 36 after the separation sensor flag 94 is removed.

[0070] The structure of the sheet stack discharge unit 36 of the discharge device 4 in the first embodiment of the present application will be described below with reference to Figure 3 Figure 3 Part (a) of FIG. 10 is a perspective view of the entire sheet stack discharge unit 36. Figure 3 Part (b) of FIG. 10 is a perspective view of a portion of the sheet stack discharge unit 36. Figure 3 Part (a) of FIG. 10 is a perspective view of the entire sheet stack discharge unit 36. Figure 3 Part (b) of FIG. 10 shows the state of the sheet stack discharge unit 36 after the separation sensor flag 94 is removed.

[0071] ​​The sheet stack discharge unit 36 has a front sub-frame 41, a top sub-frame 42, a rear sub-frame 43, a bottom sub-frame 44, a bottom discharge roller 47, a top discharge roller 48, a pivot 49, a roller support front arm 50, and a press front arm 51.

[0072] The sheet stack discharge unit 36 has the top discharge roller 48, which is a first discharge roller, having a plurality of first disks, and the bottom discharge roller 47, which is a second discharge roller, having a plurality of disks. The sheet stack discharge unit 36 is a discharge unit that discharges the recording medium sheets along the sheet discharge direction using two sets of rollers. Its structure is such that the above-mentioned disks (rotating members) of the top discharge roller 48 and the disks of the bottom discharge roller 47 are alternately positioned in a direction perpendicular to the sheet discharge direction, and further, when the disks of the top discharge roller 48 and the disks of the bottom discharge roller 47 are viewed from the sheet width direction, the disks of the top discharge roller 48 and the disks of the bottom discharge roller 47 are partially overlapped.

[0073] Further, the sheet stack discharge unit 36 has a step gear 57, a pendulum sun gear 58, a pendulum holder 59, a separation conveyance motor M2, a torsion spring 60, a pendulum planetary gear 61, a separation gear 62, a separation gear 63, a separation gear 64, and a separation gear 65.

[0074] Further, the sheet stack discharge unit 36 has a conveyance gear 66, a conveyance gear 67, a conveyance gear 68, a conveyance gear 69, a conveyance pulley 70, a pivot 71, a conveyance pulley 72, and a conveyance pulley 73. Further, the sheet stack discharge unit 36 has a timing belt 74, a timing belt 75, a roller support rear arm 76, a support plate 79, a support plate 80, a support plate 81, a support plate 82, and a pressure application rear arm 92.

[0075] The front sub-frame 41, the top sub-frame 42, the rear sub-frame 43, and the bottom sub-frame 44 are fixed to the adjacent sub-frames with small screws. The separation conveyance motor M2 is firmly attached to the rear sub-frame 43. The bottom sub-frame 44 constitutes a part of a bottom unit 95, which will be described later.

[0076] The rotation shaft of the bottom discharge roller 47 is firmly attached to the conveyance gear 69.

[0077] The top discharge roller 48 transmits a rotational driving force to the bottom discharge roller 47.

[0078] The bottom discharge roller 47 and the top discharge roller 48 are positioned such that their disks are alternately positioned in a direction parallel to their rotation axes.

[0079] The pivot 49 is press-fitted to the front sub-frame 41, and is thereby supported by the front sub-frame 41. It supports a roller support front arm 50 and a pressure application front arm 51, so that both arms can pivot with respect to the front sub-frame 41.

[0080] The roller support front arm 50 is rotatably supported by the pivot 49. The sheet stack discharge unit 36 is configured so that when a portion 50a of the roller support front arm 50 comes into contact with a stopper 41a provided to the front sub-frame 41, it is prevented from further pivoting in the counterclockwise direction of portion (b). The roller support front arm 50 is provided with a spring anchor 50a with which one end of a tension spring 91 is engaged. Figure 2

[0081] The pressure application front arm 51 is rotatably supported by the pivot 49. It pivots when pressed by a pressure application cam 90, which is driven by the separation conveyance motor M2. It is provided with a spring anchor 51d with which the other end of the tension spring 91 is engaged.

[0082] Not only is the stepped gear 57 associated with the rotational axis of the separation conveyance motor M2, but also the pendulum sun gear 58 is associated with it.

[0083] The pendulum sun gear 58 is associated with the stepped gear 57 and the pendulum planet gear 61.

[0084] The pendulum sun gear 58 is inside a pendulum holder 59, which is fixed to the pivot of the pendulum sun gear 58 so that it can oscillate about the pivot of the pendulum sun gear 58.

[0085] The separation conveyance motor M2 is associated with the stepped gear 57 through its rotational axis. When it is driven under the control of the above-mentioned control section, it drives the pressure application cam 90 and the separation sensor mark 94.

[0086] The torque spring 60 is a leaf spring. The structure of the sheet stack discharge unit 36 is such that the torque spring 60 remains in contact with the pendulum sun gear 58 and the pendulum holder 59, and when the pendulum sun gear 58 pivots, the pendulum planet gear 61 moves in the same direction as the pendulum sun gear 58 rotates, thereby causing the pendulum holder 59 to move in an oscillating manner.

[0087] The pendulum planet gear 61 is in contact with the pendulum sun gear 58. When the separation conveyance motor M2 rotates in the clockwise direction (as seen from the pinion side), the pendulum planet gear 61 comes into contact with the separation gear 62. On the other hand, when the separation conveyance motor M2 rotates in the counterclockwise direction, the pendulum planet gear 61 comes into contact with the conveyance gear 66.

[0088] ​The pendulum planet gear 61 meshes with the pendulum sun gear 58. When the separation transmission motor M2 rotates in the clockwise direction (as viewed from the pinion side), the pendulum planet gear 61 meshes with the separation gear 62, while when the separation transmission motor M2 rotates in the counterclockwise direction, the pendulum planet gear 61 meshes with the transmission gear 66.

[0089] The separation gear 63 meshes not only with the separation gear 62, but also with the separation gear 64.

[0090] The separation gear 64 meshes not only with the separation gear 63, but also with the separation gear 65.

[0091] The separation gear 65 meshes not only with the separation gear 64, but also with the transmission pulley 72.

[0092] The transmission gear 66 meshes not only with the pendulum planet gear 61, but also with the transmission gear 67.

[0093] The transmission gear 67 meshes with the transmission gear 66 as well as the transmission gear 68.

[0094] The transmission gear 68 meshes with the transmission gear 67 as well as the transmission gear 69.

[0095] The transmission gear 69 meshes with the transmission gear 68 as well as the transmission pulley 70.

[0096] The transmission pulley 70 is in indirect contact with the transmission pulley 72 through the timing belt 74.

[0097] The pivot 71 is press-fitted to the rear sub-frame 43, substantially in alignment with the pivot 49.

[0098] The transmission pulley 72 is in contact with the separation gear 65, and is in indirect contact with the transmission pulley 73 through the timing belt 75.

[0099] The transmission pulley 73 is fixed to the top discharge roller 48.

[0100] The timing belt 74 connects the transmission gear pulley 70 and the transmission pulley 72.

[0101] The timing belt 75 keeps the transmission gear pulley 70 connected to the transmission pulley 73.

[0102] The roller support rear arm 76 is rotatably supported by the pivot 71. Its rear end is engaged with one end of the pressure application spring 93.

[0103] The support unit has a plurality of support plates 79. Reference is made to Figure 4The support plate 79 is positioned so that dl is substantially equal to d2 (dl ≒ d2). Here, it is assumed that the distance between the top surface 47a of the bottom discharge roller 47 and the top surface 79c of the support plate 79 is dl, and the distance between the bottom surface 48a and the top surface 79c of the support plate 79 is d2.

[0104] Further, the support plate 79 is positioned between the top surface 47c of the shaft portion 47b of the bottom discharge roller 47 and the top surface 47a of the bottom discharge roller 47.

[0105] The support plate 80 is positioned between the bottom discharge roller 47 and the top discharge roller 48.

[0106] The support plate 81 is positioned between the bottom discharge roller 47 and the top discharge roller 48.

[0107] The support plate 82 is positioned between the bottom discharge roller 47 and the top discharge roller 48.

[0108] Incidentally, the support plates 80, 81 and 82 are positioned similarly to the support plate 79 so as to satisfy (dl ≒ d2). Further, they are positioned between the top surface 47c of the shaft portion 47b of the bottom discharge roller 47 and the top surface 47a of the bottom discharge roller 47.

[0109] The pressure application rear arm 92 is rotatably supported by the pivot 71. It is engaged with the other end of the pressure application spring 93.

[0110] <Structure of the bottom unit>

[0111] The structure of the bottom unit 95 of the discharge device 4 in the first embodiment of the present application will be described in detail below with reference to Figures 2-6

[0112] Reference is made to Figure 5 Figure 5 Part (a) of Fig. 17 is a perspective view of the bottom unit 95 (as seen from its bottom side), Figure 5 Part (b) of Fig. 17 is a perspective view of the bottom unit 95 (as seen from its top side).

[0113] The bottom unit 95 has the bottom sub-frame 44, the bottom conveyance guide 77, the support plate holder 78, the support plate 79, the support plate 80, the support plate 81, the support plate 82, the step gear 87, the support plate drive motor M3, the support plate HP sensor S4 and the support line 97.

[0114] The bottom conveyance guide 77 is connected to the sub-frame 44 by means of small screws, not shown. It supports the support plate holder 78 so that the support plate holder 78 can be moved along the direction of the arrow A in Fig. 17. Figure 5 ​​linear movement in the direction indicated by the arrow mark H or G in part (b).

[0115] The support plate holder 78 is provided with a rack 78c and a light blocking rib 78d for blocking light from reaching the support plate HP sensor S4. The bottom unit is configured such that the support plate HP sensor S2 remains exposed when the light blocking rib 78d of the support plate holder 78 remains retracted, and light is prevented from reaching the support plate HP sensor S2 when the light blocking rib 78d remains extended.

[0116] The support plates 79, 80, 81 and 82 are attached to the support plate holder 78 with small screws not shown. When the support plate holder 78 moves in the direction indicated by the arrow mark G in part (b), Figure 5 the support plates 79, 80, 81 and 82 are extended from the bottom transport guide 77, and when the support plate holder 78 moves in the direction indicated by the arrow mark H in part (b), Figure 5 the support plates 79, 80, 81 and 82 are retracted into the bottom transport guide 77.

[0117] Reference is made below to Figure 6 The support plate 79 is provided with a hole 79a in which a protruding portion 97a of the support wire 97 fits.

[0118] The step gear 87 not only engages with the rack 78c of the support plate holder 78, but also is connected with the support plate drive motor M3. It is driven by the support plate drive motor M3 to move the rack 78c to cause the support plate holder 78 to move in the direction G or H indicated in part (b). Figure 5

[0119] The support plate drive motor M3 is rotationally driven under the control of a control portion not shown in accordance with the detection result by the support plate HP sensor S4. When it is rotated, it drives the step gear 87. It causes the support plate holder 78 to move in the direction G by rotating in the direction indicated by the arrow mark E in part (b). Figure 5 It also causes the support plate holder 78 to move in the direction H by rotating in the direction F in part (b). Figure 5 Figure 5 The support plate HP sensor S4 is fixed to the sub-frame 44 by snap fit.

[0120] It is also used to control the amount of rotation of the support plate drive motor M3.

[0121]

[0122] ​​​The support line 97 is a reinforcing member. It is provided with a groove 97b for positioning the support line 97 with respect to the support plate 79 by engaging with the ribs 79b. It is held between the support plate holder 78 and the support plate 79 by being sandwiched by the support plate holder 78 and the support plate 79.

[0123] Incidentally, the support plates 80, 81 and 82 are identical in structure to the support plate 79. Therefore, their structures are not illustrated or described.

[0124] <Operation of the sheet processing rear unit>

[0125] The operation of the discharge device 4 of the image reading apparatus 100 in the first embodiment of the present application will be described in detail below.

[0126] The pre-buffering roller 22 conveys the recording medium sheet while accelerating the sheet at a predetermined timing according to the time point at which the trailing end of the sheet (in the sheet conveying direction) passes through the entrance sensor 27.

[0127] In the case where the final destination of the recording medium sheet is the top discharge tray 25, when the trailing end of the sheet in the sheet conveying direction reaches between the pre-buffering roller 22 and the reversing roller 24, the pre-buffering roller 22 decelerates the sheet to a predetermined speed (discharge speed) and then discharges the sheet into the top discharge tray 25. On the other hand, in the case where the final destination of the sheet is the bottom discharge tray 37, the pre-buffering roller 22 temporarily stops the sheet at the time point at which the trailing end of the sheet in the sheet conveying direction passes through the backward movement prevention valve, which is held pressed in the Figure 1 clockwise direction by a spring not shown. Then, they convey the sheet backward (back) to the internal discharge roller 26.

[0128] When the leading end of the recording medium sheet in the sheet conveying direction reaches the internal discharge roller 26, the reversing rollers 24 are separated from each other and are ready to accommodate the next recording medium sheet being conveyed toward the reversing rollers 24. The drive of the reversing rollers 24 is temporarily stopped while the sheet is held sandwiched by the reversing rollers 24. Then, it resumes conveying the sheet backward at the time point at which the next sheet passes. That is, the reversing rollers 24 function as a buffer by placing the recording medium sheet on the previous sheet.

[0129] When the recording medium sheet is conveyed by the internal discharge roller 26, it is conveyed to the kick-out roller 29 by the intermediate conveying roller 28. Then, it is conveyed to the sheet stacking intermediate portion 39. When the sheet reaches the sheet stacking intermediate portion 39, the leading end of the sheet in the conveying direction hits in the vertically aligned reference plate 39a of the sheet stacking intermediate portion 39, thereby aligning with the sheet on the sheet stacking intermediate portion 39.

[0130] After the sheet reaches the vertical alignment reference plate 39a, an unshown lateral alignment swing paper ejector is aligned with respect to an unshown lateral alignment reference plate.

[0131] After the sheet reaches the vertical alignment reference plate 39a, an unshown lateral alignment swing paper ejector is aligned with respect to an unshown lateral alignment reference plate.

[0132] After a preset number of recording medium sheets are aligned, they are stapled by an unshown stapler. Then, the sheet stack discharge guide 34 connected to the guide driving portion 35 moves from its standby position parallel to the sheet stack discharge unit 36, thereby pushing the sheet stack out of the sheet stack discharge unit 36.

[0133] When the sheet stack reaches the sheet stack discharge guide 34 at the front end in the direction of the pushed-out stack, the sheet stack discharge guide 34 stops. Then, it returns to the standby position.

[0134] When the sheet stack discharge unit 36 receives the sheet stack from the sheet stack discharge guide 34, it discharges the stack into the bottom discharge tray 37.

[0135] When the recording medium sheets are stacked in the top and bottom discharge trays 25 and 37, the trays are moved in the direction A2 or Bl (sheets are discharged one by one into the trays) depending on the top surface position of the uppermost recording medium sheet (which is detected by an unshown sheet surface detection sensor). Also, when the sheets in the top discharge tray 25 and the bottom discharge tray 37 are detected by an unshown sheet surface detection sensor, the trays 25 and 37 are moved in the direction Al or Bl. Thus, the top surface of the top discharge tray 25 and the top surface of the bottom discharge tray 37 are maintained at preset levels, respectively.

[0136] <Operation of sheet stack discharge unit>

[0137] The operation of the sheet stack discharge unit 36 of the image reading apparatus 100 in the first embodiment of the present application will be described in detail below.

[0138] First, the operation of the sheet stack discharge unit 36 with respect to its mechanism for separating the top discharge roller 48 from the bottom discharge roller 47 will be described with reference to Figure 7 and Figure 8 The operation of the sheet stack discharge unit 36 with respect to its mechanism for separating the top discharge roller 48 from the bottom discharge roller 47 will be described in detail below.

[0139] Reference will be made to Figure 7 , Figure 7 Part (a) of FIG. 33 shows the state of the sheet stack discharge unit 36 in which the top discharge roller 48 and the bottom discharge roller 47 are kept pressed against each other, thereby forming a nip therebetween; Figure 7Part (b) of FIG. 10 shows the state of the sheet stack discharge unit 36 in which the top discharge roller 48 and the bottom discharge roller 47 have just started to separate from each other; Figure 7 Part (c) of FIG. 10 shows the state of the sheet stack discharge unit 36 in which the top discharge roller 48 and the bottom discharge roller 47 have completely separated from each other; Figure 7 Part (d) of FIG. 10 shows the state of the sheet stack discharge unit 36 just after the separated top discharge roller 48 and the bottom discharge roller 47 start moving toward each other to form a nip.

[0140] Referring to FIG. 11, Figure 8 the horizontal axis indicates time. The vertical axis indicates the distance between the top discharge roller 48 and the bottom discharge roller 47, the number of rotations of the separation convey motor M2, and the state of the separation HP sensor S2 (listed from the top).

[0141] When the sheet stack discharge unit 36 is in the state shown in part (a) of FIG. 10, and the recording medium sheet is being conveyed, the pressure application cam 90 presses the pressure application forearm 51 in the direction A of part (a) of FIG. 10 by contacting the separation lever portion 51b. At this time, the movement of the support forearm 50 in the direction A is prevented by engagement between the stopper 41a of the front sub-frame 41 and the latch portion 50b. Thus, the top discharge roller 48 is kept pressed against the bottom discharge roller 47, that is, in a state in which the distance between the two rollers 48 and 47 is the smallest. Figure 7 Figure 7 When the sheet stack discharge unit 36 is in the state shown in part (b) of FIG. 10, the pressure application cam 90 and the separation sensor mark 94 are rotationally moved by a predetermined angle (e.g., 45 degrees) in the direction B shown in part (b) of FIG. 10 by the driving of the separation convey motor M2. Thus, the state of the separation sensor S2 changes from the state in which it blocks light to the state in which it allows light to pass. Then, when the driving of the separation convey motor M2 is stopped, the pressure application cam 90 and the separation sensor mark 94 stop after they have moved by a predetermined angle (e.g., 224.5 degrees). At the same time, the roller support forearm 50 and the pressure application forearm 51 move in the direction A of part (a) of FIG. 10 as the pressure application cam 90 rotates in the direction B.

[0142] Also, the sheet stack discharge unit 36 generates a pressure for conveying the recording medium sheet to the top discharge roller 48 by elongating the tension spring 91 which is engaged with the spring anchor 50a of the roller support forearm 50 and the spring anchor 51d of the pressure application forearm 51. Here, the disc of the top discharge roller 48 and the disc of the bottom discharge roller 47 are alternately positioned as shown in part (a) of FIG. 10. Thus, they do not contact each other. Figure 4 When the sheet stack discharge unit 36 is in the state shown in part (b) of FIG. 10, the pressure application cam 90 and the separation sensor mark 94 are rotationally moved by a predetermined angle (e.g., 45 degrees) in the direction B shown in part (b) of FIG. 10 by the driving of the separation convey motor M2. Thus, the state of the separation sensor S2 changes from the state in which it blocks light to the state in which it allows light to pass. Then, when the driving of the separation convey motor M2 is stopped, the pressure application cam 90 and the separation sensor mark 94 stop after they have moved by a predetermined angle (e.g., 224.5 degrees). At the same time, the roller support forearm 50 and the pressure application forearm 51 move in the direction A of part (a) of FIG. 10 as the pressure application cam 90 rotates in the direction B.

[0143] Figure 7 When the sheet stack discharge unit 36 is in the state shown in part (b) of FIG. 10, the pressure application cam 90 and the separation sensor mark 94 are rotationally moved by a predetermined angle (e.g., 45 degrees) in the direction B shown in part (b) of FIG. 10 by the driving of the separation convey motor M2. Thus, the state of the separation sensor S2 changes from the state in which it blocks light to the state in which it allows light to pass. Then, when the driving of the separation convey motor M2 is stopped, the pressure application cam 90 and the separation sensor mark 94 stop after they have moved by a predetermined angle (e.g., 224.5 degrees). At the same time, the roller support forearm 50 and the pressure application forearm 51 move in the direction A of part (a) of FIG. 10 as the pressure application cam 90 rotates in the direction B. Figure 7 Figure 7 ​​​The direction C1 of the portion (b) is rotationally moved.

[0144] When the sheet stack discharge unit 36 is in the state shown in the portion (c) of Figure 7 , and before it receives the recording medium, the pressure application cam 90 is rotated in the direction B by the drive of the separation conveyance motor M2, and then the drive of the separation conveyance motor M2 is stopped. Thus, the latch portion 50b of the roller support forearm 50 is separated from the stopper 41a. Therefore, the top discharge roller 48 is held in the state where it is farthest from the bottom discharge roller 47. At this time, the force from the tension spring 91 does not act on the pressure application cam 90. Also, the only force that the pressure application cam 90 receives is the moment of force about the pivot 49 that is generated by the weight of the top discharge roller 48, the roller support forearm 50, the pressure application forearm 51, and the tension spring 91. Also, at this time, the pressure application cam 90 is in contact with the separation operation lever portion 51b.

[0145] When the sheet stack discharge unit 36 is in the state shown in the portion (d) of Figure 7 , where the state of the separation sensor S2 is switched, when the separation conveyance motor M2 is driven, the pressure application cam 90 and the separation sensor flag 94 are moved in the direction B by a preset angle (for example, 30.5 degrees). Thus, the separation sensor flag 94 blocks the light from reaching the separation sensor S2.

[0146] Then, the drive of the separation conveyance motor M2 is stopped, so that the pressure application cam 90 and the separation sensor flag 94 are stopped at a position that is a preset angle (for example, 60 degrees) away from the position where they block the light. Thus, a pinch portion is formed between the top discharge roller 48 and the bottom discharge roller 47, as shown in the portion (a) of Figure 7 .

[0147] As described above, the top discharge roller 48 repeatedly performs the operations shown in the portions (a) - (d) of Figure 9 , so that a pinch portion is formed or separated from the bottom discharge roller 47.

[0148] The sheet stack discharge operation of the sheet stack discharge unit 36 will be described in detail below with reference to Figure 10 , and Figure 9 .

[0149] Reference is made to Figure 9 , Figure 9 , the portion (a) shows the state of the sheet stack discharge unit 36, where the top discharge roller 48 has been separated from the bottom discharge roller 47; Figure 9 , the portion (b) shows the state of the sheet stack discharge unit 36, where the sheet stack discharge unit 36 starts to convey the sheet stack; Figure 9Part (c) indicates the state of the sheet stacking unit 36, wherein there is a clamping part between the two rollers 48 and 47; Figure 10 Part (d) indicates the state of the sheet stack discharge unit 36, where the sheet stack discharge unit 36 ​​has just begun to discharge the sheet stack.

[0150] refer to Figure 10 , Figure 10 Part (a) shows the state of the sheet stacking unit 36, in which the support plate 79 begins to extend; Figure 10 Part (b) represents the state of the sheet stack discharge unit 36, wherein the support plate 79 is along its entire length; Figure 10 Part (c) indicates the state of the sheet stack discharge unit 36, in which the support plate 79 has just begun to retract; Figure 9 The part (d) indicates the state of the sheet stack discharge unit 36, where the sheet stack discharge unit 36 ​​has just discharged the sheet stack S.

[0151] By the way, Figure 10 and Figure 9 The diagram only shows the operation of support plate 79. However, the operation of support plates 80, 81, and 82 is the same as that of support plate 79.

[0152] Once the sheet stack S begins to stack in the middle portion 39 of the sheet layer, the top discharge roller 48 begins to move along... Figure 9 The arrow marked J1 in part (a) points away from the bottom discharge roller 47. As for the support plate 79 on the bottom conveyor guide 77, it remains in the retracted standby position.

[0153] Then, the middle portion 39 of the sheet stack performs preset operations (post-processing), such as aligning the stacked sheets, binding, etc. Then, the guide 34 is deployed using the sheet stack along... Figure 9 In part (b), the arrow marker K1 indicates the direction in which the stack of sheets S is conveyed.

[0154] Then, the middle portion 39 of the sheet stack conveys the sheet stack S to a position where it can be clamped by the bottom discharge roller 47 and the top discharge roller 48 via the sheet stack discharge guide 34. It then stops. Driven by the separation conveyor motor M2, the top discharge roller 48 begins to clamp the sheet stack S, holding it between itself and the bottom discharge roller 47 (part (c) of 9). That is, by supporting the top discharge roller 48 so that it can pivot toward or away from the bottom discharge roller 47, the sheet stack S can be discharged while applying an optimal amount of pressure, i.e., pressure proportional to the thickness of the sheet stack S.

[0155] Then, the bottom discharge roller 47 and the top discharge roller 48 begin to move along...Figure 9 direction indicated by an arrow mark K2 in part (d) of FIG. 8, so as to prepare for receiving the next sheet stack S. Then, it stops at a position where the sheet stack discharge guide 34 is received. Figure 5

[0156] Then, by driving the support plate driving motor M3, the support plate holder 78 moves in the direction G in part (b) of FIG. 8. Accordingly, the support plates 79, 80 and 81 start to move in the direction indicated by an arrow mark Ll in part (a) of FIG. 8, which is the same direction as the extending direction and the discharging direction. As for the bottom discharge roller 47 and the top discharge roller 48, they discharge the stack S. Figure 10 Figure 5

[0157] Then, the support plate holder 78 moves in the direction G in part (b) of FIG. 8, and stops. Accordingly, the support plates 79, 80 and 81 extend to their entire lengths and stop. Also, the discharging of the sheet stack S continues (part (b) of FIG. 8). Figure 10 Figure 5

[0158] Then, when the rear end (in the conveying direction) of the sheet stack S approaches the discharge, the support plate driving motor M3 is started to be driven. Accordingly, the support plate holder 78 moves in the direction H indicated by part (b) of FIG. 8. Figure 10

[0159] Accordingly, when the rear end (in the conveying direction) of the sheet stack S approaches the discharge, the support plates 79, 80, 81 and 82 start to move in the direction indicated by an arrow mark L2 in part (c) of FIG. 8, that is, the retracting direction. Figure 10

[0160] As for the timing at which the support plates 79, 80, 81 and 82 start to retract, it is controlled so that the timing of the rear end (in the conveying direction) of the sheet stack S substantially coincides with the timing at which the support plates 79, 80, 81 and 82 retract. Accordingly, at the same timing as the timing at which the discharging of the sheet stack S by the bottom discharge roller 47 and the top discharge roller 48 ends, the support plates 79, 80, 81 and 82 retract into the bottom conveying guide 77.

[0161] Then, when the rear end (in the conveying direction) of the sheet stack S passes through the bottom discharge roller 47 and the top discharge roller 48, the sheet stack S is discharged into the bottom discharge tray 37 and stacked therein (part (d) of FIG. 8). Figure 4

[0162] ​​​​​​​​Immediately after the leading end of the sheet stack S in the direction Ll passes the bottom discharge roller 47 and the top discharge roller 48, the leading end of the support plates 79, 80, 81, and 82 in the direction Ll will be on the opposite side of the leading end of the sheet stack S in the direction Ll, and thus the sheet stack S can be easily discharged.

[0163] As described above, when the sheet stack S is discharged, the support plates 79, 80, 81, and 82 are extended and support the sheet stack S from the bottom side thereof. Thus, when the sheet stack S is discharged, it is kept separate from the sheet stack S in the bottom discharge tray 37. Thus, when the sheet stack S is pushed out of the sheet stack discharge unit 36, it does not interfere with the sheet stack S in the bottom discharge tray 37, and vice versa.

[0164] Furthermore, the present embodiment can make the structural components of the support plates 79, 80, 81, and 82 the same. Thus, the present embodiment can reduce the cost of the sheet stack discharge unit 36.

[0165] The sheet stack discharge unit 36 is provided with a plurality of support plates 79, 80, 81, and 82 that are aligned at a predetermined interval in the width direction (the left-right direction in FIG. 6) perpendicular to the discharge direction Ll. Thus, the sheet stack S is reliably held. Figures 1 to 6

[0166] Furthermore, the support plates 79, 80, 81, and 82 are located between the top discharge roller 48 and the bottom discharge roller 47. Thus, they can be extended or retracted without interfering with the top discharge roller 48 and the bottom discharge roller 47.

[0167] Furthermore, the distance d1 between the top surface of the support plates 79, 80, 81, and 82 and the top surface of the bottom discharge roller 47 is equal to the distance d2 between the bottom surfaces of the top discharge roller 48. Thus, the sheet stack S can be reliably supported.

[0168] Furthermore, the support plates 79, 80, 81, and 82 are arranged between the top surface 47c of the shaft portion 47b of the bottom discharge roller 47 and the top surface 47a of the bottom discharge roller 47. Thus, the sheet stack S can be reliably supported without increasing the pressure applied to the sheet stack S by the sheet stack discharge unit 36.

[0169] Furthermore, the support plates 79, 80, 81, and 82 are provided with internal support wires 97. Thus, they can reliably support the sheet stack S.

[0170] ​In this embodiment, the sheet stack discharge unit 36 ​​is provided with support plates 79, 80, 81, and 82. These support plates 79, 80, 81, and 82 support the sheet stack S from the bottom side by extending along the sheet stack discharge direction. The sheet stack S is discharged into the bottom discharge tray 37 by the bottom discharge roller 47 and the top discharge roller 48. Moreover, the support plates 79, 80, 81, and 82 remain retracted before and after the sheet stack S is discharged onto the bottom discharge tray 37 by the bottom discharge roller 47 and the top discharge roller 48. Therefore, not only can the recording medium sheet be prevented from suffering frictional damage, but the size of the motor used to drive the bottom discharge roller 47 can also be reduced, thereby making it easier to remove the sheet from the bottom discharge tray 37.

[0171] (Example 2)

[0172] The imaging device in the second embodiment of the present invention is different from the imaging device in the first embodiment. Figure 11 The structure shown is identical (except for the structure of its support plate 179). Therefore, it will not be described in detail.

[0173] refer to ​ The sheet stack discharge unit 36 ​​is configured such that the top surface 179c of the support plate 179 that contacts the sheet stack S is located on the bottom side of the straight line t and is approximately parallel to the straight line t, which is tangent to the bottom discharge roller 47 and the support plate 179.

[0174] More specifically, the support plate 179 has a top surface 179c, which is an inclined flat surface parallel to the straight line t between point 48b on the bottom surface 48a of the top discharge roller 48 (which is close to the support plate 179 on the support plate 179 side) and point 47d on the top surface 47a of the bottom discharge roller 47 (which is close to the support plate 179 on the support plate 179 side). Furthermore, the support plate 179 is located below the straight line t between point 48b on the bottom surface 48a of the top discharge roller 48 (which is on the support plate 179 side) and point 47d on the top surface 47a of the bottom discharge roller 47 (which is on the support plate 179 side).

[0175] Here, points 48a and 47d are located on the support component side. Incidentally, the support plate in this embodiment is equivalent to support plates 80, 81, and 82, and its structure is similar to support plate 179.

[0176] Incidentally, the operation of the post-processing unit and the sheet stack discharge unit in this embodiment is the same as that in the first embodiment. Therefore, they will not be described here.

[0177] As described above, in this embodiment of the present application, the discharge device 4, which is connected to the main assembly of the image forming device for forming a color image that is sensitive to stress applied to the sheet stack S, is provided with a support plate 179 having a corrugated shape similar to that of the sheet stack S, which is formed by the bottom discharge roller 47 and the top discharge roller 48 thereof. Therefore, the pressure generated between the sheet stack S and the support plate 179 can be smaller. Thus, it is able to discharge the recording medium sheet while keeping the image on the recording medium in good condition.

[0178] The above-described embodiments of the present application are not intended to limit the scope of the present application. Needless to say, these embodiments can be variously changed within the gist of the present application.

[0179] More specifically, in the first and second embodiments of the present application, the bottom discharge roller 47 and the top discharge roller 48 are positioned such that the disks of the bottom discharge roller 47 and the disks of the top discharge roller 48 are alternately arranged in a direction parallel to their rotational axes. However, these embodiments are not intended to limit the scope of the present application. That is, the present application is also compatible with a discharge device configured such that the disks of the top discharge roller and the disks of the bottom discharge roller are in the same position in a direction parallel to the rotational axes of the bottom and top discharge rollers.

[0180] The present application not only enables the recording medium sheet to be prevented from being damaged by friction, but also enables the size of the motor for driving the discharge tray to be reduced, thereby making the recording medium sheet in the discharge tray easier to be taken out of the tray.

[0181] While the present application has been described with reference to example embodiments, it is to be understood that the application is not limited to the disclosed example embodiments. The scope of the following claims is to be based upon the full breadth of the disclosure, with all variations and equivalents of the structures and functions being encompassed therein.

Claims

1. A discharge apparatus for discharging a sheet, comprising: an alignment unit on which a supplied stack of sheets is stacked, the alignment unit serving to align the stacked sheets as a sheet bundle; a discharge unit serving to discharge the sheet bundle of the sheets aligned by the alignment unit; a discharge tray on which the sheets discharged by the discharge unit are stacked; and a support unit serving to support the sheet bundle from below by extending along a sheet discharge direction of the sheet bundle as the sheet bundle is discharged by the discharge unit onto the discharge tray, and to be accommodated in a direction opposite to the sheet discharge direction when the discharge unit finishes discharging the sheet bundle, wherein the discharge unit is composed of a first roller and a second roller which are arranged vertically to each other at different positions in a sheet width direction perpendicular to the sheet discharge direction; wherein the support unit is arranged between the first roller and the second roller with respect to the sheet width direction; and wherein the support unit includes a top surface which is an inclined flat surface parallel to a straight line between an end point of a lower surface of the first roller serving as a top discharge roller near the support unit and on the support unit side and an end point of an upper surface of the second roller serving as a bottom discharge roller near the support unit and on the support unit side. The support unit is provided with a plurality of support plates arranged at intervals in the sheet width direction perpendicular to the sheet discharge direction.

2. The discharge device of claim 1, wherein: The discharge unit is provided with a pair of rollers composed of the first roller including a plurality of first rotatable members and the second roller including a plurality of second rotatable members, and discharges the sheets in the sheet discharge direction by the pair of rollers, the plurality of first rotatable members and the plurality of second rotatable members are arranged at different positions from each other with respect to the sheet width direction perpendicular to the sheet discharge direction, and partially overlap when viewed in the sheet width direction, and 3. The discharge device of claim 2, wherein: the plurality of support plates are arranged between the first roller and the second roller with respect to the sheet width direction. The support plates are arranged between an upper surface of a rotation shaft portion of the second roller and an upper surface of the second roller.

4. The discharge device of claim 3, wherein: The support plates are arranged below a straight line connecting the end point of the lower surface of the first roller near the support plates and on the support unit side and the end point of the upper surface of the second roller near the support plates and on the support unit side.

5. The discharge device of claim 3, wherein: The first roller is pivotally supported so as to be able to move up and down.

6. The discharge device of claim 3, wherein: The support unit includes a reinforcing member.

7. The discharge device of claim 1, wherein: After a leading end of the sheet bundle in the sheet discharge direction passes through the discharge unit, a leading end of the support unit in the sheet discharge direction is located on a side in a direction opposite to the sheet discharge direction from the leading end of the sheet bundle in the sheet discharge direction.

8. The discharge device of claim 1, wherein:

9. An image forming apparatus, comprising: the discharge apparatus according to any one of claims 1 to 8; an image forming portion serving to form an image on a sheet, and serving to supply the sheet on which the image is formed to the discharge apparatus. ​

Images