JP2005126245A - Sheet post-treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a sheet post-treating device while preventing the rear end unevenness of sheets caused by the tip hanging of the sheets when stacking large-sized sheets on an intermediate stacker. <P>SOLUTION: When placing the large-sized sheets of predetermined size or larger on the intermediate stacker, a clamping discharge means is put in an open state, and the tip parts of the sheets are projected onto a paper delivery tray while allowing the paper delivery tray to stand by in an upper position. The tip parts of the sheets can thereby be held on the paper delivery tray or on the sheets placed on the paper delivery tray. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention accepts a sheet on which an image is formed by an image forming apparatus such as an electrophotographic copying machine, a printer, or a printing machine, automatically binds the sheet using a stapler, and then discharges the sheet onto a discharge tray by a discharge unit. More particularly, the present invention relates to a sheet post-processing apparatus having a stapling mode and a non-stapling mode (including an offset mode).

  A sheet post-processing device called a finisher is used as a device that collates a plurality of sheets of image-recorded sheets discharged from the image forming apparatus for each number of copies and binds them by a stapler.

  This finisher is connected to a main body of an image forming apparatus such as a copying machine or a printer, and is driven in response to a sequence operation of a copy or print process.

  Therefore, for an image forming apparatus capable of processing an image forming process at high speed, a finisher capable of high speed processing capable of performing a function following the processing speed is required.

  Regarding finishers capable of such high-speed processing, JP-A-60-142359, JP-A-60-158463, JP-A-62-239169, JP-A-62-228802, JP-A-63-267667, JP-A-2 -276691 and Japanese Patent Publication No. 5-41991.

  In the sheet post-processing apparatus, the image-recorded sheets carried out from the image forming apparatus main body are sequentially stacked while being aligned in the intermediate stacker, and after one set of sheet bundles are stored, sheet post-processing such as a stapler is performed. The sheet bundle that has been bound and carried is carried on a discharge belt provided at the bottom of the intermediate stacker, and is further sandwiched by a pair of upper and lower discharge rollers and discharged onto a discharge tray.

  The sheet placement surface is inclined so that the discharge tray becomes higher from the rear end toward the front end, and the sheet rear end abutting reference member is erected on the rear end side of the discharge tray. The leading edge of the sheet discharged from the rear end side of the discharge tray is discharged in the direction of the front end of the discharge tray. After the trailing edge of the sheet has passed over the sheet trailing edge abutting reference member, A sheet stack that performs falling and aligns the trailing edge of the sheet in the sheet discharge direction by sliding down the upper surface of the sheet placed on the sheet discharge tray and contacting the sheet trailing edge butting reference member The apparatus is widely used as described in Japanese Patent Application Laid-Open No. 57-48558 (Patent Document 1).

A sheet post-processing apparatus disclosed in Japanese Patent Laid-Open No. 2-233456 (Patent Document 2) has a paper discharge tray that can move horizontally at right angles to the sheet conveyance direction, and discharges paper depending on whether or not post-processing is performed on the sheet. The relative initial position between the tray and the discharge unit is changed.
JP 57-48558 A JP-A-2-233456

(First issue)
23A, 23B, and 23C are schematic views showing a conventional sheet stacking apparatus. In the sheet stacking apparatus shown in FIG. 23A, since the angle θ1 formed by the sheet placing surface of the sheet discharge tray T and the sheet rear end abutting reference member K is close to a right angle, natural fall due to the weight of the sheet is uncertain. Thus, the trailing edge of the sheet does not return to the contact position of the winding roller R, and the trailing edge abutting reference member K may not be reached. In the sheet stacking apparatus shown in FIG. 23B, since the angle θ2 formed by the sheet placement surface of the sheet discharge tray T and the sheet rear end abutting reference member K is close to an acute angle, the natural fall due to the sheet's own weight is ensured. However, the vertical component force due to the weight of the sheet is reduced, the upper surface of the sheet is swollen, the sheets are not pressed and stacked, and the number of sheets that can be stacked is reduced. Further, as in the sheet stacking apparatus shown in FIG. 23C, as the angle θ2 formed by the sheet placement surface of the sheet discharge tray T and the sheet rear end abutting reference member K becomes closer to an acute angle, the sheet discharge tray T The leading edge of the sheet P stacked on the top of the upper sheet hangs down from the leading edge of the lower sheet, and the overhang increases as the number of stacked sheets increases. Due to the weight of the sheet in the overhang portion, the upper surface of the sheet in the stacking portion swells, the sheets are not pressed and stacked, and the number of sheets that can be stacked is reduced.
(Second problem)
24A and 24B are schematic views showing a conventional sheet stacking apparatus, in which FIG. 24A shows the front of the sheet stacking apparatus, and FIG. 24B shows the side. The sheet P stacked on the sheet discharge tray T slides down on the sheet discharge tray T or the upper surface of the sheet P already placed on the sheet discharge tray T by the weight of the sheet, and further comes into sliding contact with the rotating winding roller R. The upper surface of the uppermost sheet abuts against the sheet rear end abutting reference member K. For this purpose, the upper surface detection sensor detects the upper surface of the uppermost sheet P and drives the discharge tray T up and down so that the outer peripheral surface of the winding roller R and the upper surface of the uppermost sheet P are in contact with each other with a predetermined pressure. Let However, if the sheet P is a stapled sheet bundle, a portion of the sheet bundle having the staple needle ST protrudes and comes into strong contact with the winding roller R, and the outer peripheral surface of the winding roller R is shaved. In particular, when a plurality of sheet bundles P are stacked on the sheet discharge tray T, the portion having the staples ST of the sheet bundle P overlaps and protrudes greatly, so that the outer peripheral surface of the winding roller R is significantly damaged by the staples ST. Is done.
(Third issue)
Japanese Patent Application Laid-Open No. 63-310459 discloses a sheet post-processing apparatus that detects a rising reference position when a sheet is not stacked on the discharge tray and also stacks a sheet on the discharge tray. Detecting means for detecting the stacking amount on the paper discharge tray. In this sheet post-processing apparatus, the discharge tray is lowered by a detection signal of a detection unit that detects the rising reference position. In FIG. 24A, in the winding operation of the sheet P by the winding roller R, if the winding roller R rotates in contact with the upper surface of the sheet already placed on the discharge tray or the discharge tray, When one sheet discharged on the sheet descends on the sheet discharge tray and comes into contact with the sheet rear end abutting reference member K, the sheet is not caught by the take-up roller R, and sheet irregularity occurs.
(Fourth issue)
When stacking large size sheets on the intermediate stacker in the staple mode, the leading edge of the sheet protrudes from the discharge roller pair and hangs down due to its own weight, and when the sheet slides down on the intermediate stacker, the trailing edge of the sheet is a reference member against the trailing edge of the sheet. Unevenness occurs without contacting K.

A sheet post-processing apparatus described in Japanese Patent Application Laid-Open No. 63-247267 stores a staple tray (intermediate stacker) for temporarily stacking and storing recorded sheets (sheets) before being stapled, and stapled recorded sheets. A stacker tray (discharge tray) is provided, and the staple tray (intermediate stacker) can stack sheets of all sizes. Accordingly, a part of the discharge tray is used as an auxiliary tray for the intermediate stacker for temporarily stacking sheets, and the sheets stacked on the intermediate stacker are discharged across the intermediate stacker and the discharge tray via the discharge roller pair. This is completely different from the sheet post-processing apparatus of the present invention for the purpose of achieving the above.
(Fifth issue)
When a stapled sheet bundle and one sheet are discharged by a common discharge roller pair and placed on a common discharge tray, one sheet and a stapled sheet bundle (for example, 50 sheets) In this case, since the thickness and the weight of the sheet are different from each other, good discharge cannot be performed. The sheet post-processing apparatus disclosed in Patent Document 2 uses a common discharge roller pair and a common discharge tray for the staple mode and the non-staple mode (including the offset mode). Since the amount of lowering of the discharge tray is not changed depending on the mode, the above problem occurs.

  The object of the present invention is to solve the above problems and improve the results. (1) Increase the stacking amount of sheets discharged on the paper discharge tray. (2) Prevent damage of the winding roller, especially a large number of sheets. (3) Prevents entanglement due to the wrapping roller and eliminates unevenness of the sheet, (4) Dripping of the leading edge of the sheet when a large sized sheet is stacked on the intermediate stacker The sheet trailing edge processing device is prevented from becoming uneven and the sheet post-processing apparatus is made compact, and (5) a large number of sheet bundles and a single sheet can be discharged as well. A sheet post-processing apparatus (finisher) is provided.

  The object of the present invention can be achieved by the following constitution.

(Claim 1)
In a sheet post-processing apparatus in which sheets conveyed from the image forming apparatus are stacked and aligned on an intermediate stacker, stapled by a stapler, discharged by a nipping and discharging unit, and stacked on a liftable discharge tray.
When a large-sized sheet of a predetermined size or more is placed on the intermediate stacker, the nipping and discharging means is opened, the end of the sheet is projected onto the discharge tray, and the discharge tray is A sheet post-processing apparatus that waits at a position to hold an end portion of a sheet on a sheet discharge tray or a sheet placed on the sheet discharge tray.

(Claim 2)
2. The sheet post-processing according to claim 1, wherein when a small-sized sheet smaller than a predetermined size is placed on the intermediate stacker, the sheet discharge tray is made to wait at a standby position lower than the upper position. apparatus.

(Claim 3)
When binding a predetermined number of sheets or more, after binding the sheets, the discharge tray is lowered for a certain time, and after the sheets are discharged onto the discharge tray, the discharge tray is raised, Wait again in the upper position,
When binding fewer than a predetermined number of sheets, after the sheets are bound, the discharge tray is lowered for a certain period of time, and after the sheets are discharged onto the discharge tray, the standby position below the upper position is waited. The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus waits at a position.

  Another object of the present invention is to provide a sheet post-processing apparatus that sequentially introduces a plurality of sheets carried out from an image forming apparatus, discharges them by a nipping and discharging means, and stacks them on a discharge tray that can be raised and lowered. A sheet discharge surface having a sheet stacking surface inclined upward in the sheet discharge direction, and an abutting surface in contact with a rear end portion in the discharge direction of a plurality of sheets stacked on the inclined sheet stacking surface are sheets. A sheet post-processing apparatus comprising: a sheet discharge abutting plate that is set at an angle close to a right angle with respect to the stacking surface and the abutting surface is inclined with respect to the vertical surface. The

  In addition, the above-described objects include a stapling mode in which a sheet conveyed from an image forming apparatus is bound by a stapler, and then a sheet bundle is discharged onto a discharge tray that can be lifted and lowered by a nipping and discharging unit. In the sheet post-processing apparatus having a non-staple mode for discharging the sheet onto a discharge tray that can be moved up and down by the nipping and discharging means, the staple mode and the non-staple mode are configured such that the sheet is discharged by a common discharge roller pair and the discharge tray. Two sensors that detect the upper surface of the sheet placed on the paper discharge tray at different vertical heights are provided, and in the staple mode, the lower surface of the paper discharge tray is detected by a sheet upper surface detection signal from the lower sensor. In the non-staple mode, the upper side sensor detects the sheet upper surface detection signal in the non-staple mode. It is achieved by a sheet post-processing apparatus, characterized by elevation control the discharge tray to hold the upper position.

  Further, the object is to provide a sheet discharged from the nipping and discharging means in the sheet post-processing apparatus that introduces the sheet carried out from the image forming apparatus, discharges the sheet by the nipping and discharging means, and stacks the sheet on a liftable discharge tray. A sheet discharge sensor that detects passage of the trailing edge of the sheet, a sheet discharge abutting plate having an abutting surface that contacts the trailing edge of the sheet in the sheet discharge direction, and an upper surface rear end of the sheet discharged onto the sheet discharge tray. A rotatable sheet discharge auxiliary rotating member that slides into contact with the sheet and contacts the abutting surface of the sheet ejection abutting plate, and a detection that detects the upper surface position of the sheet placed on the sheet ejection tray. And a control means for controlling the raising and lowering of the paper discharge tray by the detection means, and the paper discharge tray is lowered for each sheet discharge by the nipping and discharging means, and the discharged sheet is abutted against the paper discharge Plank After making contact with the contact surface by its own weight, the discharge tray is raised and slidably contacted with the rear end portion of the sheet discharged by the discharge auxiliary rotation member to the contact surface of the discharge contact plate This is achieved by a sheet post-processing apparatus characterized in that it abuts.

  Further, the object is to stack the sheets carried out from the image forming apparatus on the intermediate stacker, align them, bind them with a stapler, discharge them by a nipping / discharging means, and stack them on a liftable discharge tray. In the post-processing apparatus, when a large-sized sheet of a predetermined size or more is placed on the intermediate stacker, the nipping and discharging means is opened, and the leading end of the sheet protrudes onto the discharge tray, and The sheet discharge tray is made to stand by at an upper position where the binding process is not performed, and the leading edge of the sheet can be held on the sheet discharge tray or on the sheet placed on the sheet discharge tray. Achieved by processing equipment.

  Further, the above objects are a stapling mode in which sheets conveyed from the image forming apparatus are stapled by a stapler, and then a sheet bundle is discharged onto a discharge tray that can be lifted and lowered by a nipping and discharging unit. In a sheet post-processing apparatus having a non-staple mode for discharging the sheet onto a sheet discharge tray that can be raised and lowered by the nipping and discharging unit, a sheet discharge sensor that detects a rear end of the sheet discharged from the nipping and discharging unit, and the discharge An upper surface detection sensor for detecting an upper surface of a sheet placed on the paper tray, a driving unit for driving the sheet discharge tray up and down each time the sheet is discharged from the nipping and discharging unit, an output of the sheet discharge sensor, and the Control means for controlling the raising and lowering drive of the discharge tray according to the output of the upper surface detection sensor, and the stapling mode and the non-stapling In a mode, it is achieved by a sheet post-processing apparatus characterized by having different descent amount of the discharge tray.

  Further, the above objects are a stapling mode in which sheets conveyed from the image forming apparatus are stapled by a stapler, and then a sheet bundle is discharged onto a discharge tray that can be lifted and lowered by a nipping and discharging unit. In a sheet post-processing apparatus having a non-staple mode for discharging the sheet onto a sheet discharge tray that can be raised and lowered by the nipping and discharging unit, a sheet discharge sensor that detects a rear end of the sheet discharged from the nipping and discharging unit, and the discharge An upper surface detection sensor for detecting an upper surface of a sheet placed on the paper tray, a driving unit for driving the sheet discharge tray up and down each time the sheet is discharged from the nipping and discharging unit, an output of the sheet discharge sensor, and the Control means for controlling the raising and lowering drive of the discharge tray according to the output of the upper surface detection sensor, and the stapling mode and the non-stapling In a mode, it is achieved by a sheet post-processing apparatus characterized by having different fall time of the output tray.

  With the sheet post-processing apparatus of the present invention, the staple mode discharge means and the non-staple mode (including shift process) discharge means are configured as one, thereby reducing the size of the apparatus and simplifying the mechanism, thereby reducing the manufacturing cost. Reduction was achieved. Further, stapled sheet bundles discharged onto the paper discharge tray, unevenness of sheets discharged one by one, scattering, damage to the discharge rollers, and the like were prevented, and satisfactory sheet discharge was achieved.

  Next, an embodiment of the sheet post-processing apparatus of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a configuration of the sheet post-processing apparatus (finisher). The sheet post-processing device is installed by adjusting the position and height so that the receiving portion of the sheet P is aligned with the paper discharge port of the main body of the image forming apparatus (copier, printer, etc.), and corresponds to the operation of the main body of the image forming apparatus. Then, it is connected to the control system so as to be driven.

  The conveyance path of the sheet P connected to the downstream of the sheet conveyance of the inlet roller pair 1 of the receiving portion is branched into three systems: an upper first conveyance path 100, an intermediate second conveyance path 200, and a lower third conveyance path 300. In addition, the sheet P is fed to one of the conveyance paths by selecting the angle occupied by the switching gates G1, G2, and G3.

FIG. 2A is a schematic diagram showing the conveyance path of the sheet P by the first conveyance path 100 (one-dot chain line), and FIG. 2B is a schematic diagram showing the conveyance path of the sheet P by the second conveyance path 200 (one-dot chain line). FIGS. 3A and 3B are schematic diagrams showing the conveyance path of the sheet P by the third conveyance path 300 (one-dot chain line), and FIG. 3B shows the conveyance path of the sheet P by the fourth conveyance path 400 (one-dot chain line). FIG.
(1) First conveyance path 100 (printer mode, image surface downward discharge)
In FIG. 2A, the sheet P discharged from the image forming apparatus main body upward in the image plane is conveyed by the inlet roller pair 1 and passes through the passage 11 below the upper first switching gate G1. Then, it passes through the passage 12 above the second switching gate G2 which is sandwiched between the conveyance roller pair 2 and obliquely below the second conveyance path 200, and passes through the conveyance roller pair 3, the passage 13, and the conveyance roller pair 4. Then, after stopping once, it is switched back by the conveying roller pair 2, 3 and 4 converted to the reverse driving, and passes through the passage 15 above the first switching gate G1, and further the passage 16 above, and the discharge roller The pair 7 is discharged onto the discharge tray 8 at the upper outside of the apparatus with the image surface facing downward (face down) and placed in page order.
(2) Second transport path 200 (copy mode, image surface upward discharge, non-staple mode including offset discharge)
In FIG. 2B, the sheet P discharged from the image forming apparatus main body with the image surface facing upward (face-up) is conveyed by the inlet roller pair 1 and is a path below the upper first switching gate G1. 11, passing through the passage 12 above the second switching gate G <b> 2 that is sandwiched between the transport roller pair 2 and obliquely below the second transport path 200, and passes through the transport roller pair 3, the passage 13, and the transport roller After passing through the pair (shift roller pair) 4 and the passage 14, the paper is discharged and placed on the paper discharge tray 6 outside the apparatus by the discharge roller pair (nipping discharge means) 5 upward. In the automatic document feeder (ADF) connected to the image forming apparatus, exposure processing is performed from the final document, and a copy of the final page subjected to image formation processing is sequentially sent to the sheet post-processing device, so that the image surface faces upward. The sheets are stacked on the discharge tray 6 in page order.
(3) Third transport path 300 (copy mode, image surface upward discharge, stapling mode)
In FIG. 3A, sheets P discharged from the copy of the last page subjected to image formation processing in the image forming apparatus main body upward (face-up) and sequentially fed to the sheet post-processing apparatus are It is conveyed by the inlet roller pair 1, passes through the lower passage 11 of the upper first switching gate G <b> 1, is sandwiched by the conveying roller pair 2, and is obliquely below the third conveyance path 300. It passes through the passage 17 below the switching gate G3, and is sent to the staple processing unit 20 through the conveying roller pair 9 and the passage 18.

  The sheet P sandwiched and conveyed by the conveying roller pair 21 downstream of the passage 18 is discharged into the space above the inclined intermediate stacker 22 and is stacked on the intermediate stacker 22 or the intermediate stacker 22. After the sheet trailing edge is discharged from the conveying roller pair 21, the sheet P turns downward due to its own weight, slides down on the inclined surface of the intermediate stacker 22, and is stapled (binding). Means) Abuts against a sheet abutting surface (stopper member) 31 near 30 and stops. A conveyance auxiliary rotating member (winding member) 23 rotated by a belt wound around a pulley that rotates coaxially with the lower roller 21B of the conveying roller pair 21 is in sliding contact with the upper surface of the sliding sheet P, thereby causing the sheet P to slide. When the switchback is performed, the stopper member 31 is surely contacted by the sliding contact action of the conveyance auxiliary member 23.

  Reference numeral 24 denotes a pair of alignment members that are movably provided on both side surfaces of the intermediate stacker 22. The alignment member 24 is movable in a direction perpendicular to the sheet conveying direction. When the sheet P is discharged onto the intermediate stacker 22, the alignment member 24 is opened wider than the sheet width, and slides down on the intermediate stacker 22 to stop the stopper member. When the sheet 31 comes into contact with the sheet 31 and stops, the width of the sheet bundle is aligned (aligned) by tapping the side edge in the width direction of the sheet. When a predetermined number of sheets P are stacked and aligned on the intermediate stacker 22 at this stop position, the stapler 30 performs a binding process (stapling process) to bind the sheet bundle.

A cutout portion is formed in a part of the sheet stacking surface of the intermediate stacker 22, and a plurality of discharge belts 27 wound around the drive pulley 25 and the driven pulley 26 are rotatably driven. A discharge claw 28 is integrally formed on a part of the discharge belt 27, and the tip of the discharge claw 28 draws an elliptical locus as shown by a dashed line in the figure. The stapled sheet bundle P is held on the discharge belt 27 by the discharge claw 28 of the discharge belt 27 and placed on the discharge belt 27. The sheet bundle P slides obliquely upward on the placement surface of the intermediate stacker 22. It is pushed up and proceeds to the nip position of the discharge roller pair (nip and discharge means) 5. The sheet bundle P sandwiched between the rotating discharge roller pair 5 is discharged and stacked on the discharge tray 6 with the image surface facing upward.
(4) Fourth transport path 400 (copy mode, image surface upward discharge)
In FIG. 3B, the sheet P discharged from the main body of the image forming apparatus upward on the image surface is conveyed by the entrance roller pair 1 and is conveyed substantially vertically upward, and the passage ( The sheet passes through the fourth conveying path 400), passes through the upper path 16, and is discharged onto the sheet discharge tray 8 at the upper part outside the apparatus by the discharge roller pair 7 with the image surface facing upward (face up).

  FIG. 4 is a configuration diagram showing a drive system of the sheet post-processing apparatus. The motor M1 rotates the driving roller 9A (left roller) of the conveying roller pair 9 of the third conveying path 300 via the timing belts B1 and B2, and also the conveying roller pair 2 of the second conveying path 200 via the gear train. The driving roller 2A (lower roller), the driving roller 3A (lower roller) of the conveying roller pair 3 and the driving roller 4A (upper roller) of the conveying roller pair 4 are rotated. Further, the driving roller 1A (right roller) of the inlet roller pair 1 of the receiving portion is rotated via the timing belt B3, and further, the driving roller 7A (lower roller) of the discharge roller pair 7 is rotated via the timing belt B4.

  The motor M2 rotates the upper driving (hereinafter referred to as upper roller) roller 5A of the discharge roller pair 5 via the timing belts B5 and B6, and the lower drive roller of the discharge roller pair 5 via the gear train and the timing belt B7. (Hereinafter referred to as the lower roller) 5B is rotated. Further, the pulley that drives the lower roller 5B rotates the drive pulley 25 via the timing belt B8 and rotates the discharge belt 27.

  The motor M4 drives and rotates the driving pulley 61 via the gear train, and rotates the wire 63 that winds the driving pulley 61 and the upper driven pulley 62. A base portion of the paper discharge tray 6 is fixed to a part of the wire W by a locking member 64. The discharge tray 6 can be moved up and down along the rail member 66 by the roller 65 rotatably supported at the base thereof sliding on the rail member 66 and the wire 63 rotating.

  FIG. 5 is a cross-sectional view showing the staple processing unit 20 and the paper discharge unit, and FIG. 6 is a plan view of the staple processing unit 20.

  In FIG. 6, the two alignment members 24 are arranged symmetrically with respect to the center line CL, and can be simultaneously moved in a direction orthogonal to the conveyance direction of the sheet P. The left and right alignment members 24 are respectively fixed to the timing belt 32 and slidably move on the guide bar 33. The timing belt 32 rotates from the stepping motor M6 via an intermediate gear train. The alignment member 24 shown in FIG. 6 shows a state at the home position. This home position is detected and controlled by a projection (detected part) 24A provided on the alignment member 24 and a home position detection sensor 34 provided on the intermediate stacker 22. In addition, the dashed-dotted line shown in FIG. 6 shows the sheet P of various sizes. In the present embodiment, as an example, sheets P of various sizes having lengths in the longitudinal direction of A3 size, B4 size, 11 ″ × 17 ″, 8.5 ″ × 14 ″ are set as large size sheets. The sheet P having a shorter length was set as a small size sheet. The distance L from the stopper surface (abutting surface) m that abuts the sheet of the stopper member 31 near the stapler 30 to the nip position n of the discharge roller pair 5 is set to a position that distinguishes the large size from the small size. Set. That is, the various small-sized sheets P are all placed on the upstream side of the discharge roller pair 5 because the length in the transport direction is shorter than the distance L. On the other hand, each of the large-sized various sheets P has a length in the transport direction that is longer than the distance L, so that the leading end protrudes downstream from the nip position of the discharge roller pair 5 and is on the discharge tray 6. Also put on. In order to place and align and staple this large size sheet P, the nip portion of the discharge roller pair 5 is controlled to open and close.

  In FIG. 5, the discharge roller pair 5 includes an upper roller 5A and a lower roller 5B that are connected to the motor M2 shown in FIG. The lower roller 5B is driven to rotate at a fixed position. The upper roller 5 </ b> A that can be driven and rotated is supported by the holding member 51, and can swing along an arc-shaped long groove 53 provided on the side plate of the apparatus main body about the support shaft 52. That is, the pinion gear g1 on the drive shaft of the motor M5 is decelerated through the gear train composed of the gears g2, g3, g4, and g5, and rotates the disk 54. An eccentric pin 55 implanted at an eccentric position of the disc 54 is rotatably connected to one end of the crank lever 56. The other end of the crank lever 56 is rotatably engaged with a pin 57 provided on the upper portion of the holding member 51. When the pinion gear g1 of the motor M5 is driven to rotate and the disk 54 is rotated halfway through the gear train, the crank lever 56 moves, and the holding member 51 that holds the upper roller 5A is moved around the support shaft 52. Then, it is swung clockwise along the long groove 53. When the rotating disk 54 is rotated halfway and the detected portion 58 provided on the disk 54 passes through the optical path of the photo interrupter type sensor PS5, the driving of the motor M5 is stopped and the upper roller 5A is discharged from the sheet. Stop with the passage open.

  FIG. 7 is a cross-sectional view showing a state where the upper roller 5A of the discharge roller pair opening / closing drive means 50 is opened and stopped. In this state where the discharge passage is open, a large size sheet is carried from the intermediate stacker inlet roller pair 21 onto the intermediate stacker 22 and subjected to alignment and stapling.

FIG. 8 is a sectional view showing a standby state of the lower discharge roller unit and the upper discharge roller unit. 9 is a cross-sectional view taken along arrow A in FIG. The lower roller unit includes a rotary shaft 501 rotatably supported on both side walls of the sheet post-processing apparatus main body, and a pulley 502 fixed to one shaft end, a plurality of lower rollers 5B having a rubber layer on the peripheral surface, and a peripheral surface And a plurality of entraining rollers (sponge rollers) 5C having a flexible elastic material layer, which are driven and rotated by the motor M2 via the belt B7 around which the pulley 502 is wound.
In the middle of the plurality of lower rollers 5 </ b> B and the plurality of sponge rollers 5 </ b> C, one paper discharge guide plate 503 is supported so as to be swingable about the support shaft 504. The paper discharge guide plate 503 is pulled upward by a coil spring (spring member) 505 stretched between discharge roller upper units, which will be described later, and comes into contact with a stopper 507 via a buffer material 506. At the time of this contact, the upper surface of the paper discharge guide plate 503 protrudes upward from the outer peripheral surface of the sponge roller 5C.

  The upper roller 5A of the upper discharge roller unit is composed of a rotary shaft 511 rotatably supported on both side walls of the upper discharge roller unit and having a pulley 512 fixed to one end of the shaft, and the belt B6 around which the pulley 512 is wound. And driven and rotated by the motor M2 in the same manner as the discharge roller lower unit.

  As described with reference to FIG. 7, the holding member 51 of the upper discharge roller unit can swing around the support shaft 52, and the cover upper part 51 </ b> A abuts against the stopper 513 of the sheet post-processing apparatus main body and swings. Stop. The support shaft 52 includes an arm member 514 that rotatably supports both shaft ends of the rotation shaft 511 of the discharge roller upper unit, and a lever member 515 that engages with a pin 517 planted on the plunger 516 of the solenoid SD. Are fixed and can swing together. The solenoid SD drives the pressure contact and release of the upper roller 5A with the lower roller 5B. A stopper member 518 is provided outside the sheet passing region at the bottom of the arm member 514. The front end of the stopper member 518 is installed so that the upper roller 5A and each peripheral surface of the paper discharge guide plate 503 maintain a gap s. The sheet P sandwiched between the shift roller pair 4 can pass smoothly between the upper roller 5A and the lower roller 5B which are spaced apart from each other while keeping the gap s without contacting the sponge roller 5C.

  FIG. 10 is a cross-sectional view of the discharge roller upper unit and the discharge roller lower unit during sheet discharge. When voltage is applied to the solenoid SD from the stopped state, the plunger 516 is attracted, and the pin 517 rotates counterclockwise around the support shaft 52 against the biasing force of the return spring against the lever member 515. Let The arm member 514 integrated with the support shaft 52 is also rotated counterclockwise, the tip of the stopper member 518 abuts against the upper surface of the paper discharge guide plate 503, and the upper roller 5A presses against the lower roller 5B. Stop. In this pressed and rotated state, the sheet discharged from the shift roller pair 4 is pressed and sandwiched and discharged onto the discharge tray 6. Alternatively, the sheet bundle after the stapling process is conveyed by the discharge belt 27 having the discharge claw 28, and discharged to the discharge tray 6 from the nip position where the upper roller 5A and the lower roller 5B are pressed and rotated.

  FIG. 11 is a cross-sectional view of the upper discharge roller unit and the lower discharge roller unit showing a state in which the sheet bundle P is discharged from the discharge roller pair 5. In the figure, PS2 is a paper discharge sensor, and 520 is an actuator of the paper discharge sensor PS2, which detects the passage of the rear end of the sheet bundle P and detects the completion of paper discharge. When the completion of discharging the sheet bundle P is detected, the energization to the solenoid SD is stopped and the initial state shown in FIG. 8 is restored.

  In the embodiment of the present invention, a sheet post-processing apparatus connected to a copying machine is shown. However, the present invention is also applicable to an image forming apparatus such as a printer or a facsimile, or a sheet post-processing apparatus used by connecting to a light printing machine. Is possible.

  A first embodiment will be described with reference to FIG. FIG. 12A is a schematic diagram showing the discharged sheet stacking portion of the sheet post-processing apparatus according to the present invention. The inclination angle θ3 (for example, 30 ° to 40 °) of the sheet placement surface of the discharge tray 6 with respect to the horizontal plane is such that the sheet discharged onto the discharge tray 6 or on the sheet surface placed on the discharge tray. This is the angle required to slide down reliably. Further, the angle θ4 formed by the sheet stacking surface of the sheet discharge tray 6 and the sheet rear end abutting reference member (hereinafter referred to as a rear end reference member) 67 is preferably as close to 90 °. Therefore, the rear end reference member 67 is inclined with respect to the vertical plane V at an angle α. Here, if θ4 = about 90 °, the inclination angle α of the rear end reference member 67 is substantially equal to the inclination angle θ3 of the paper discharge tray 6. Thus, by setting the trailing edge reference member 67 to be inclined, the sheet P discharged by the discharge roller pair 5 is slid on the sheet discharge tray, and the trailing edge reference member 67 is moved by the winding roller 5C. Can be reliably aligned with the trailing edge of the sheet being substantially perpendicular. However, when the rear end reference member 67 is disposed at an inclination angle α, there is a drawback that the sheet post-processing apparatus main body is increased in size.

  FIG. 12B is a schematic view showing another embodiment of the discharged sheet stacking portion of the sheet post-processing apparatus according to the present invention. The sheet placement surface of the sheet discharge tray 6 occupies a large area for placing the surface including the front end portion of the sheet P, and the first sheet placement surface 6A having the inclination angle θ3 and the vicinity of the sheet rear end are placed. The sheet mounting surface 6B has a gentle inclination angle θ5 (for example, 10 ° to 20 °). The rear end reference member 67 is set at an inclination angle θ4 (about 90 °) with respect to the sheet placement surface 6B having the inclination angle θ5. That is, the rear end reference member 67 is inclined with respect to the vertical plane VP at an inclination angle β. Since the inclination angle β is substantially equal to the inclination angle θ5 and can be set to be significantly smaller than the inclination angle α, the sheet post-processing apparatus main body can be downsized, and the sheet rear end alignment can be reliably achieved. Is done.

  A second embodiment will be described with reference to FIG. FIG. 13A is a cross-sectional view showing the upper limit position of the paper discharge tray 6 in the non-staple mode. On the upper part of the rear end reference member 67, a photo interrupter type tray upper limit sensor PS6 and a swingable actuator 68 are installed. When the paper discharge tray 6 is driven up, and one tip 68A of the actuator 68 comes into contact with the upper surface of the paper discharge tray 6 or the upper surface of the sheet P placed on the paper discharge tray 6, the actuator 68 The other tip portion 68B opens the light detection portion of the upper limit sensor PS6 to switch it off, and stops driving the paper discharge tray 6. The stop position of the paper discharge tray 6 is a position where the upper surface of the paper discharge tray 6 or the upper surface of the sheet P placed on the paper discharge tray 6 comes into contact with the winding roller 5C with a predetermined pressure. In this state, the rotating winding roller 5 </ b> C is always pressed against the sheet P with a predetermined pressure and sends the sheet P to the rear end reference member 67 to align the rear end. As the number of sheets P stacked on the discharge tray 6 increases, the discharge tray 6 is driven downward, and the uppermost surface of the sheets P stacked on the discharge tray 6 is the tray upper limit sensor PS6 and the actuator. It is detected and controlled by 68 and is always held at a constant upper surface height, and is brought into pressure contact with the outer peripheral surface of the entraining roller 5C with a predetermined pressure.

  FIG. 13B is a cross-sectional view showing the upper limit position of the paper discharge tray 6 in the staple mode. A photo-interrupter type tray upper limit sensor PS7 and a swingable actuator 69 are installed above the rear end reference member 67 and below the tray upper limit sensor PS6. When the discharge tray 6 is driven upward and one tip 69A of the actuator 69 comes into contact with the upper surface of the stapled sheet bundle P placed on the discharge tray 6, The front end portion 69B opens the light detection portion of the tray upper limit sensor PS7 to switch it off, and stops driving the paper discharge tray 6. The stop position of the paper discharge tray 6 is a position having a gap a where the sheet bundle P placed on the paper discharge tray 6 does not contact the winding roller 5C. In this state, the sheet bundle P discharged from the discharge roller pair 5 is placed on the paper discharge tray 6, and the rear end of the sheet bundle P enters below the winding roller 5 </ b> C and contacts the rear end reference member 67. And stop. As the number of sheet bundles P stacked on the discharge tray 6 increases, the discharge tray 6 is driven downward, and the uppermost surface of the sheet bundle P stacked on the discharge tray 6 is the tray upper limit sensor PS7. Further, the detection is controlled by the actuator 69, and the constant gap a is always maintained.

A third embodiment will be described with reference to FIGS. 14, 15, and 16. FIG. FIG. 14 is a schematic diagram showing the discharge and stacking process of the sheet P on the paper discharge tray 6 in the non-staple mode, FIG. 15 is a block diagram for raising and lowering the paper discharge tray 6, and FIG. It is a flowchart.
(1) When one sheet is nipped and discharged by the discharge roller pair 5 and the passage of the trailing end of the sheet is detected by the paper discharge sensor PS2, the motor drive circuit drives the motor M4 for raising and lowering the paper discharge tray. Then, the discharge tray 6 starts to descend. FIG. 14A shows a sheet discharge state before the discharge tray 6 starts to descend.
(2) The discharge tray 6 is lowered, and the tip end portion 69A of the actuator 69 in contact with the upper surface of the discharge tray 6 or the uppermost surface of the sheet P placed on the discharge tray 6 is swung. When the leading end portion 69B of the tray upper limit sensor PS7 opens the light detection portion of the tray upper limit sensor PS7 and switches it off, the lowering of the discharge tray stops. At this time, the tray 69B is placed on the upper surface of the discharge tray 6 or on the discharge tray 6. A gap b is formed between the uppermost surface of the sheet P and the outer peripheral surface of the entraining roller 5C.
(3) When the timer in the control means 70 starts from the switch-off of the tray upper limit detection sensor PS7 and the timer counts up a predetermined time, the motor drive circuit starts driving the motor M4, and the discharge tray 6 is The rising is started and the gap b is reduced. Between the lowering and rising of the paper discharge tray 6, the sheet P discharged onto the upper surface of the paper discharge tray 6 or the uppermost surface of the sheet P placed on the paper discharge tray 6 is lowered to The end passes through the lower side of the winding roller 5C, and the trailing end of the sheet further rotates on the winding roller 5C and the upper surface of the discharge tray 6 or the uppermost surface of the sheet P placed on the discharge tray 6. It is clamped and brought into contact with the rear end reference member 67. In this way, when the trailing edge of the sheet P passes through the winding roller 5C, the gap b is formed, so that the trailing edge of the curled sheet P hits the outer peripheral surface of the winding roller 5C and causes a conveyance failure. , There will be no misalignment of the trailing edge of the sheet.
(4) The sheet discharge tray 6 is raised, and the upper surface of the sheet discharge tray 6 or the uppermost surface of the sheet P placed on the sheet discharge tray 6 comes into contact with the actuator 69 and swings. When the upper limit sensor PS7 is switched on, the motor driving circuit stops driving the motor M4 and the raising of the paper discharge tray 6 is stopped.
(5) The above-described lowering and raising operations of the paper discharge tray 6 are performed each time one sheet P is discharged, and the motor by the tray upper limit sensor PS7 and the timer at the timing when the rear end of the sheet enters the winding roller 5C. A gap b is formed for each sheet discharge by driving M4. This prevents sheet irregularities due to poor winding.

A fourth embodiment will be described with reference to FIGS. Figure 17 is a fragmentary cross-sectional view of the staple processing section 20 in the staple mode, (a) shows the places the sheet bundle P _A small-sized on the intermediate stacker 22, abut the sheet rear end stopper member 31 (B) shows a state in which the large-size sheet bundle P _B is placed on the intermediate stacker 22 and the sheet trailing edge is brought into contact with the stopper member 31. FIG. 18 is a block diagram for raising / lowering the discharge tray 6, and FIG. 19 is a flowchart for raising / lowering the discharge tray 6.

As the sheet P _A small-sized as shown in FIG. 5, are stacked on the intermediate stacker 22, after the stapling process, is discharged onto the discharge tray 6 that is stopped at the standby position of the staple mode (FIG. 17 (a)). However, in such a configuration, as described with reference to FIG. 7, the large-size sheet P _B has the discharge roller pair 5 in an open state so that the leading end of the sheet is taken out from the discharge roller pair 5. . That is, the large-sized sheet P _B comes into contact with the stopper member 31 near the stapler 30 at the rear end of the sheet, and on the lower roller 5B and the entraining roller 5C on the intermediate stacker 22 and the discharge roller pair 5 that stops rotating. And the leading edge of the sheet protrudes outside the machine. Among the large sized sheets P _B , in particular, in the case of 11 ″ × 17 ″ sized sheets or A3 size sheets, which are the largest, the leading edge of the sheet that protrudes outside the machine as the sheets are stacked. It hangs down and curves around the lower roller 5B and the entraining roller 5C. In such a state, the sheet P conveyed from the intermediate stacker entrance roller pair 21 and fed into the intermediate stacker 22 is prevented from advancing due to the leading edge of the sheet being bent, and therefore, along the inclined surface of the intermediate stacker 22. There is a problem in that the sheet does not slide down, does not contact the stopper member 31, and the sheet becomes uneven.

The sheet post-processing apparatus according to the present invention controls the standby position of the paper discharge tray 6 to change depending on the sheet size. When a large-size sheet P _B is stacked on the intermediate stacker 22, FIG. As shown, the sheet discharge tray 6 is raised to the standby position in the offset mode, and the sheet leading end protruding from the intermediate stacker 22 is placed on the upper surface of the sheet discharge tray 6 or on the sheet discharge tray 6. Support so that it contacts the top surface of P. As a result, the leading end of the sheet is lifted, and the sheet P on the intermediate stacker 22 is easily lowered and comes into contact with the stopper member 31. In addition, by using the discharge tray 6 that can be raised and lowered as an auxiliary tray for the intermediate stacker 22 on which the sheet P is placed before the stapling process, the intermediate stacker 22 can be downsized and the sheet post-processing apparatus can be made compact. It became possible.

  Note that when stacking 10 or more large size sheets such as 11 ″ × 17 ″ size sheets or A3 size sheets, the sheet discharge tray 6 is raised to the upper offset mode standby position and waited, and the intermediate stacker 22 is The leading edge of the sheet conveyed upward is supported by the upper surface of the paper discharge tray 6 or the uppermost surface of the sheet bundle P placed on the paper discharge tray 6. At the end of the stapling operation, the discharge tray 6 is lowered for a certain time, and after the discharge sensor PS2 detects that the sheet bundle P has been discharged onto the discharge tray 6, the discharge tray 6 is raised. Again stop at the full offset mode standby position.

  However, when the large-sized sheet is a small number of less than 10 sheets and a large number of sheet bundles are stacked, the staples of the sheet bundle already placed on the paper discharge tray 6 are overlapped, and only this portion is thickened. (See FIG. 24 (b)), the upper surface of the tray upper limit sensor PS7 for detecting the upper surface of the sheet bundle on the sheet discharge tray protrudes higher than the detection surface, and the upper portion of the staple needle bites into and damages the outer peripheral surface of the winding roller 5C. End up. In order to prevent this, when stacking less than 10 large-sized sheets, the discharge tray 6 is not raised, but is set to the standby position in the stapling mode shown in FIG.

  A fifth embodiment will be described with reference to FIGS. 20, 21, and 22. FIG. When a stapled sheet bundle and one sheet are discharged by a common discharge roller pair and placed on a common discharge tray, one sheet and a stapled sheet bundle (for example, 50 sheets) In this case, since the thickness and the weight of the sheet are different from each other, good discharge cannot be performed. The present invention solves this problem. FIG. 20 is a block diagram of raising / lowering control of the discharge tray 6. FIG. 21 is a flowchart of raising / lowering control of the discharge tray 6. FIG. It is.

  The time from when the discharge sensor PS2 detects the passage of the trailing end of the sheet (or the stapled sheet bundle) P discharged from the intermediate stacker 22 to the start of lowering of the discharge tray 6 is A, the discharge tray. The time when 6 is descending is defined as B, and the times A and B are set to different times in the offset mode and the staple mode. Table 1 shows the lowering time and the lowering distance of the paper discharge tray 6 in both operations of the offset mode and the staple mode.

  Since the stapled sheet bundle is generally thick, as shown in Table 1, in the staple mode, the lowering time of the discharge tray 6 is increased from that of the staple mode, and the lowering distance is increased, so that the sheet bundle is discharged onto the discharge tray 6. By setting the stop position of the sheet discharge tray 6 when receiving the sheet P to be received to a position larger than the maximum sheet bundle thickness, good sheet discharge is achieved.

Sectional drawing which shows the structure of the sheet | seat post-processing apparatus of this invention. FIG. 4 is a schematic diagram illustrating a sheet conveyance path along a first conveyance path, and a schematic diagram illustrating a sheet conveyance path along a second conveyance path. FIG. 6 is a schematic diagram showing a sheet conveyance path by a third conveyance path, and a schematic diagram showing a sheet conveyance path by a fourth conveyance path. The block diagram which shows the drive system of a sheet | seat post-processing apparatus. Sectional drawing which shows a staple processing part and a paper discharge part. The top view of a staple processing part. Sectional drawing which shows the state which the upper roller of the discharge roller pair opened and stopped. Sectional drawing which shows the standby state of a discharge roller lower unit and a discharge roller upper unit. FIG. 9 is a cross-sectional view taken along arrow A in FIG. 8. Sectional drawing of the discharge roller upper unit and the discharge roller lower unit during sheet discharge. FIG. 4 is a cross-sectional view illustrating a state in which a sheet bundle is discharged from a discharge roller pair. The schematic diagram which shows the discharge sheet stacking part of the sheet | seat post-processing apparatus by this invention. Sectional drawing which shows the upper limit position of the paper discharge tray in non-staple mode and staple mode. FIG. 6 is a schematic diagram illustrating a process of discharging and stacking sheets on a sheet discharge tray in a non-staple mode. FIG. 3 is a block diagram for controlling the lifting and lowering of a paper discharge tray. 8 is a flowchart for raising and lowering the discharge tray. FIG. 4 is a cross-sectional view of a main part of a staple processing unit on which a small-size sheet bundle is loaded and a main-part cross-sectional view of a staple processing unit on which a large-size sheet bundle is loaded in a staple mode. FIG. 3 is a block diagram for controlling the lifting and lowering of a paper discharge tray. 8 is a flowchart for raising and lowering the discharge tray. FIG. 3 is a block diagram for controlling the lifting and lowering of a paper discharge tray. 8 is a flowchart for raising and lowering the discharge tray. A timing chart of raising and lowering control of the discharge tray. Schematic diagram showing a conventional sheet stacking apparatus. The schematic diagram which shows the front and side surface of the conventional sheet stacking apparatus.

Explanation of symbols

1 Inlet roller pair 2, 3, 9 Conveying roller pair 4 Conveying roller pair (shift roller pair, offset roller pair)
5 Discharge roller pair (Nipping discharge means)
7 Discharge roller pair 5A Upper roller (Upper drive roller)
5B Lower roller (lower drive roller)
5C Entrainment roller (sponge roller)
6,8 Paper discharge tray 11, 12, 13, 14, 15, 16, 17, 18, 19 Path 20 Staple processing unit 21 Conveying roller pair (intermediate stacker inlet roller pair)
22 Intermediate stacker 27 Discharge belt 28 Discharge claw 30 Stapler 31 Stopper member 50 Discharge roller pair opening / closing drive means 67 Sheet rear end abutting reference member (sheet ejection abutting plate, rear end reference member)
70 Control means 100 First transport path 200 Second transport path 300 Third transport path 400 Fourth transport path M1, M2, M3, M4, M5, M6 Motor P Sheet, sheet bundle PS1 Entrance sensor PS2 Paper discharge sensor PS3 Stacker Entrance sensor PS6, PS7 Tray upper limit sensor

Claims (3)

In a sheet post-processing apparatus in which sheets conveyed from the image forming apparatus are stacked and aligned on an intermediate stacker, stapled by a stapler, discharged by a nipping and discharging unit, and stacked on a liftable discharge tray.
When a large-sized sheet of a predetermined size or more is placed on the intermediate stacker, the nipping and discharging means is opened, the end of the sheet is projected onto the discharge tray, and the discharge tray is A sheet post-processing apparatus that waits at a position to hold an end portion of a sheet on a sheet discharge tray or a sheet placed on the sheet discharge tray. 2. The sheet post-processing according to claim 1, wherein when a small-sized sheet smaller than a predetermined size is placed on the intermediate stacker, the sheet discharge tray is made to wait at a standby position lower than the upper position. apparatus. When binding a predetermined number of sheets or more, after binding the sheets, the discharge tray is lowered for a certain time, and after the sheets are discharged onto the discharge tray, the discharge tray is raised, Wait again in the upper position,
When binding fewer than a predetermined number of sheets, after the sheets are bound, the discharge tray is lowered for a certain period of time, and after the sheets are discharged onto the discharge tray, the standby position below the upper position is waited. The sheet post-processing apparatus according to claim 1, wherein the sheet post-processing apparatus waits at a position.

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