JP2013112479A - Sheet stacking device, sheet processor and image forming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely stack sheets to allow alignment of the sheets regardless of the kind of paper or the presence/absence of curl.SOLUTION: The device includes: a shift tray 202 for stacking sheets; a discharge roller pair 6 for discharging a conveyed sheet onto the shift tray 202; a lifting mechanism 14 for raising and lowering the shift tray 202; an auxiliary tray 13 for temporarily stacking the sheet discharged by the discharge roller pair 6 before moving it onto the shift tray 202; an auxiliary tray drive mechanism 400 for moving forward and backward the auxiliary tray 13 relative to the shift tray 202; and an auxiliary tray belt 402 disposed along the upper and lower surfaces of the auxiliary tray 13, the belt aligning the sheet while controlling the movement of the sheet in interlocking with the forward and backward movement of the auxiliary tray 13.

Description

  The present invention relates to a sheet stacking apparatus, a sheet processing apparatus, and an image forming system, and in particular, a sheet-like recording medium such as a loaded sheet, a recording sheet, a transfer sheet, and an OHP sheet (in this specification, simply “sheet”). A sheet stacking apparatus having an auxiliary tray for temporarily stacking the sheet stacking sheet during discharge, a sheet processing apparatus including the sheet stacking apparatus, the sheet stacking apparatus, or a sheet processing apparatus including the sheet stacking apparatus, and copying. The present invention relates to an image forming system including an image forming apparatus such as an image forming apparatus, a printer, a facsimile, or a digital multifunction peripheral.

  Conventionally, a sheet processing apparatus that performs various processes on sheets discharged from the image forming apparatus, for example, post-processing such as alignment, binding, folding, and bookbinding, and here, a sheet post-processing apparatus that performs post-processing. The devices referred to are known and widely used. In such a sheet post-processing apparatus, when a sheet is discharged to a discharge tray, depending on the type, size, or usage environment of the sheet, the sheet to be discharged is pushed out or stacked. May stick to each other, resulting in poor alignment and poor alignment accuracy. As a countermeasure, the conventional machine uses an auxiliary tray, and once loaded onto the auxiliary tray and then loaded onto the tray, or after the tray is discharged, the roller rotates in the direction opposite to the conveying direction (also referred to as a return roller). ), The sheet is conveyed in a direction opposite to the sheet conveying direction, and the abutting sheet is aligned with the end face of the tray.

  As such a technique, for example, the invention described in Patent Document 1 (Japanese Patent Laid-Open No. 10-324449) is known. In order to prevent buckling of a sheet discharged onto the processing tray, the present invention discharges the sheet conveyed from the image forming means onto the processing tray, and is provided below the discharging means and on the processing tray. An auxiliary tray positioned above and capable of moving forward and backward in a predetermined direction; a detecting means disposed on the upstream side of the discharge direction of the sheet of the discharge means or discharge means; and a drive means for driving the auxiliary tray forward and backward. And a control unit that controls the driving unit based on the sheet detection result by the detection unit, and is configured to be stacked on the auxiliary tray and then discharged to the tray when the tray is discharged.

  However, in the invention described in Patent Document 1, the return roller that returns the sheet in the direction opposite to the sheet discharge direction and the auxiliary tray come to the same position and interfere with each other, or friction between the sheets such as coated paper is large. In the case of a sheet, the sheet stuck and buckled, and the sheet could not be aligned with the return roller. If the alignment is not performed in this way, the sheet is displaced when the number of sheets stacked on the stacking tray is increased or when the curl of the sheet is stacked. As a result, the sheet bundle collapsed before reaching the designed number of stacked trays, and it was impossible to stack the designed number of sheets.

  Therefore, a problem to be solved by the present invention is to make it possible to align sheets regardless of the type of paper or the presence or absence of curling, and to reliably stack sheets on a stacking tray.

  In order to solve the above problems, the present invention provides a stacking unit that stacks sheets, a sheet discharge unit that discharges a conveyed sheet onto the stacking unit, a lifting unit that lifts and lowers the stacking unit, and the discharge unit. A temporary stacking means for temporarily stacking a sheet discharged by the paper means before moving onto the stacking means, an advancing / retracting drive means for moving the temporary stacking means back and forth on the stacking means, and a temporary stacking means The sheet stacking apparatus includes a movement alignment unit that is arranged along the upper surface and the lower surface, controls movement of the sheet in conjunction with the advance and retreat operation of the temporary stacking unit, and aligns the sheet.

  According to the present invention, sheets can be aligned regardless of the type of paper or the presence or absence of curling, and sheets can be stacked reliably.

1 is a diagram illustrating a system configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus according to an embodiment of the present invention. It is the schematic block diagram which looked at the end surface binding processing tray in FIG. 1 from the stacking surface side of the tray. It is a perspective view which shows schematic structure of the end surface binding processing tray in FIG. 1, and its attachment mechanism. It is a perspective view which shows operation | movement of the discharge | release belt in FIG. FIG. 2 is a perspective view illustrating a main part of a configuration of a sheet discharge unit of the sheet post-processing apparatus illustrated in FIG. 1. FIG. 6 is an enlarged view of the paper discharge unit shown in FIG. 5. FIG. 10 is an operation explanatory diagram illustrating an operation when a sheet is discharged to the shift tray side. FIG. 6 is a diagram illustrating a state when sheets are stacked on an auxiliary tray. It is a figure which shows operation | movement when a sheet | seat is moved to the shift tray side from an auxiliary tray, and shows the state at the time of auxiliary tray retreat. It is a figure which shows operation | movement when a sheet | seat is moved to the shift tray side from an auxiliary | assistant tray, and shows the state when falling from an auxiliary | assistant tray and stack | stacking. FIG. 11 is a diagram illustrating an operation of aligning sheets stacked on a shift tray in the state of FIG. 10. 3 is a block diagram illustrating a control configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus. FIG.

  The present invention reduces the contact with the already loaded paper by stacking once on the auxiliary tray when the first sheet is discharged, and then moving the sheet from the auxiliary tray to the paper discharge tray. By aligning the sheets on the lower surface, sticking of the sheets is prevented, and alignment is ensured to improve stackability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an image forming system including a sheet post-processing apparatus PD as an image processing apparatus according to the present embodiment and an image forming apparatus PR.

  In FIG. 1, an image forming apparatus PR is an image processing circuit that converts input image data into printable image data, and an optical writing apparatus that performs optical writing on a photoconductor based on an image signal output from the image processing circuit. A developing device for developing the latent image formed on the photosensitive member by optical writing, a transfer device for transferring the toner image visualized by the developing device to the sheet, and a fixing device for fixing the toner image transferred on the sheet At least the sheet on which the toner image is fixed is sent to the sheet post-processing apparatus PD, and desired post-processing is performed by the sheet post-processing apparatus PD. Here, the image forming apparatus PR is of an electrophotographic system as described above, but any known image forming apparatus such as an ink jet system or a thermal transfer system can be used. In this embodiment, the image processing circuit, the optical writing device, the developing device, the transfer device, and the fixing device constitute image forming means.

  The sheet post-processing apparatus PD is attached to a side portion of the image forming apparatus PR, and the sheet discharged from the image forming apparatus PR is guided to the sheet post-processing apparatus PD. The sheet post-processing apparatus PD includes a conveyance path A, a conveyance path B, a conveyance path C, a conveyance path D, and a conveyance path H, and the sheet is a post-processing unit (in this embodiment) that performs post-processing on a single sheet. It is first transported to a transport path A having a punch unit 50) as a punching means.

  The conveyance path B is a conveyance path that leads to the upper tray 201 through the conveyance path A, and the conveyance path C is a conveyance path C that leads to the shift tray 202. The conveyance path D is a conveyance path D that leads to a processing tray F that performs alignment, stapling, and the like (hereinafter also referred to as an “end face binding processing tray”). The conveyance path A is distributed to the conveyance paths B, C, and D by the branch claw 15 and the branch claw 16, respectively.

  In this sheet post-processing apparatus, punching (punch unit 50), sheet alignment + edge binding (jogger fence 53, end surface binding stapler S1), sheet alignment + saddle binding (saddle stitch upper jogger fence 250a, Processing such as saddle stitching lower jogger fence 250b, saddle stitching stapler S2), sheet sorting (shift tray 202), center folding (folding plate 74, folding roller 81), and the like can be performed. Therefore, the transport path A and the subsequent transport path B, transport path C, and transport path D are selected according to the processing. Further, the conveyance path D includes a sheet storage portion E, and an end face binding processing tray F, a saddle stitching middle folding processing tray G, and a paper discharge conveyance path H are provided on the downstream side of the conveyance path D.

  A common conveyance path A upstream of the conveyance path B, the conveyance path C, and the conveyance path D includes an inlet sensor 301 that detects a sheet received from the image forming apparatus PR, and an inlet roller 1 and a punch unit 50 downstream of the sensor. The punch and waste hopper 50a, the conveying roller 2, the first and second branching claws 15, and the branching claws 16 are sequentially arranged. The first and second branch claws 15 and 16 are held in the state of FIG. 1 by a spring (not shown) (initial state), and the branch claws 15 and 16 are turned on by turning on the first and second solenoids (not shown). , Respectively, and the combination of the branch directions of the first and second branch claws 15 and 16 is changed by selecting ON / OFF of the first and second solenoids, the transport path B, the transport path C, The sheet is distributed to the conveyance path D.

When the sheet is guided to the conveyance path B, the state shown in FIG. 1, that is, the first solenoid remains OFF (the first branch claw 15 is in the initial state). As a result, the sheet is discharged from the conveying roller 3 to the upper tray 201 via the upper discharge roller 4.
When the sheet is guided to the conveyance path C, the first and second solenoids are turned on from the state shown in FIG. 1 (the second branch claw 16 is in the initial state), so that the branch claw 15 branches upward. The nail | claw 16 will be in the state which each rotated below. Thus, the sheet is conveyed to the shift tray 202 side through the conveying roller 5 and the discharge roller pair 6 (6a, 6b). In this case, the sheets are sorted. Sheet sorting is performed by reciprocating the (shift) discharge roller pair 6 (6a, 6b), the return roller 13, the paper surface detection sensor 330, the shift tray 202, and the shift tray 202 in a direction perpendicular to the sheet conveyance direction. This is performed by a shift mechanism (not shown) and a shift tray lifting mechanism that lifts and lowers the shift tray 202.

  When the sheet is guided to the conveying path D, the first solenoid that drives the first branch claw 15 is turned ON, and the second solenoid that drives the second branch claw is turned OFF, so that the branch claw 15 and the branch Both the claws 16 are rotated upward, and the sheet is guided from the conveying roller 2 to the conveying path D through the conveying roller 7. The sheet guided to the conveyance path D is guided to the end face binding processing tray F, and the sheet subjected to alignment, stapling, and the like in the end face binding processing tray F is guided to the shift tray 202 by the guide member 44. The sheet is fed to the saddle stitching / saddle folding processing tray G (hereinafter also simply referred to as “saddle stitching processing tray”). When guided to the shift tray 202, the sheet bundle PB is discharged from the discharge roller pair 6 to the shift tray 202. Further, the sheet bundle PB guided to the saddle stitching processing tray G side is folded and bound by the saddle stitching processing tray G and is discharged from the lower discharge roller 83 to the lower tray 203 through the discharge conveyance path H. The

  On the other hand, a branching claw 17 is disposed in the conveyance path D, and is held in the state shown in the figure by a low load spring (not shown). After the trailing edge of the sheet conveyed by the conveyance roller 7 passes through the branching claw 17. The sheet can be reversed along the turn guide 8 by reversing at least the conveyance roller 9 among the conveyance rollers 9 and 10 and the staple discharge roller 11. As a result, the sheet is guided from the rear end of the sheet to the sheet storage portion E to be retained (pre-stacked), and can be conveyed while being overlapped with the next sheet. By repeating this operation, two or more sheets can be stacked and conveyed. Reference numeral 304 denotes a prestack sensor for setting a reverse feed timing when the sheets are prestacked.

  When the sheet is guided to the conveyance path D and sheet alignment and end binding are performed, the sheets guided to the end surface binding processing tray F by the staple discharge roller 11 are sequentially stacked on the end surface binding processing tray F. In this case, for each sheet, the tapping roller 12 and the rear end reference fence 51 are aligned in the vertical direction (sheet conveyance direction), and the jogger fence 53 is in the horizontal direction (also referred to as a direction perpendicular to the sheet conveyance direction—the sheet width direction). Are matched. The end face binding stapler S1 as the binding means is driven by a staple signal from the CPU 101 (to be described later) between the end of the job, that is, from the last sheet of the sheet bundle PB to the first sheet of the next sheet bundle, and the binding process is performed. The sheet bundle PB subjected to the binding process is immediately sent to the paper discharge roller pair 6 by the discharge belt 52 (see FIG. 2) on which the discharge claw 52a protrudes, and is discharged to the shift tray 202 set at the receiving position. Paper.

  As shown in FIGS. 2 and 4, the discharge belt 52 is positioned at the center of alignment in the sheet width direction, is stretched between pulleys 62, and is driven by a discharge belt drive motor 157. A plurality of discharge rollers 56 are arranged symmetrically with respect to the discharge belt 52, are provided so as to be rotatable with respect to the drive shaft, and function as driven rollers.

  The release claw 52 a is configured such that the home position is detected by a release belt HP sensor 311, and this release belt HP sensor 311 is turned on / off by a discharge claw 52 a provided on the discharge belt 52. Two discharge claws 52a are arranged at opposing positions on the outer periphery of the discharge belt 52, and the sheet bundle PB accommodated in the end face binding processing tray F is moved and conveyed alternately. Further, if necessary, the discharge belt 52 is rotated in the reverse direction, and the sheet bundle stored in the end face binding processing tray F on the back surface of the discharge claw 52a opposite to the discharge claw 52a opposite to the sheet bundle PB. It is also possible to align the leading ends of the PB in the transport direction.

  In FIG. 1, reference numeral 110 denotes a rear end pressing lever, which is positioned at the lower end of the rear end reference fence 51 so that the rear end of the sheet bundle PB accommodated in the rear end reference fence 51 can be pressed. It reciprocates in a direction substantially perpendicular to the end face binding processing tray F. The sheets P discharged to the end-face binding processing tray F are tapped for each sheet and aligned in the vertical direction (sheet conveyance direction) with the roller 12, but the trailing edge of the sheets stacked on the end-face binding processing tray F is curled. If the waist is weak, the rear end tends to buckle and swell due to the weight of the seat itself. Further, as the number of stacked sheets increases, the gap for the next sheet in the rear end reference fence 51 is reduced, and the vertical alignment tends to be deteriorated. Therefore, the trailing edge pressing mechanism is configured to reduce the swelling of the trailing edge PT so that the sheet P easily enters the trailing edge reference fence 51, and directly pressing the sheet P or the sheet bundle PB is the trailing edge. A holding lever 110 is provided.

  In FIG. 1, reference numerals 302, 303, 304, 305, and 310 denote sheet detection sensors that detect whether or not a sheet has passed at a provided position or whether or not a sheet is stacked.

  FIG. 2 is a schematic configuration diagram of the end face binding processing tray F as viewed from the tray stacking surface side, and corresponds to the case of viewing from the right side surface of FIG. In the same figure, the alignment in the width direction of the sheet received from the upstream side image forming apparatus PR is performed by jogger fences 53a and 53b, and the vertical direction is on rear end reference fences 51a and 51b (indicated by reference numeral 51 in FIG. 1). It is abutted and aligned. The rear end reference fences 51a and 51b are respectively provided with stack surfaces 51a1 and 51b1 that hold the sheet rear end PT in contact with and hold the sheet rear end PT, and support the sheet rear end PT at two points. After completion of the alignment operation, binding processing is performed by the end-face binding stapler S1, and the discharge belt 52 is driven counterclockwise by the discharge belt drive motor 157, as can be seen from the perspective view showing the operation of the discharge belt in FIG. The sheet bundle PB after the binding process is lifted to a predetermined position by the rear end reference fences 51 a and 51 b, scooped by the discharge claw 52 a attached to the discharge belt 52, and discharged from the end face binding processing tray F. Reference numerals 64a and 64b are a front side plate and a rear side plate. Further, this operation can be performed in the case of an unbound bundle that is not subjected to the binding process after the alignment process.

  FIG. 3 is a perspective view showing a schematic configuration of the end face binding processing tray F and its attached mechanism. As shown in the drawing, the sheets P guided to the end-face binding processing tray F by the staple paper discharge roller 11 are sequentially stacked on the end-face binding processing tray F. At this time, when the number of sheets P to be discharged to the end face binding processing tray F is one, alignment in the vertical direction (sheet conveyance direction) is performed between the tapping roller 12 and the rear end reference fence 51 for each sheet. The jogger fences 53a and 53b perform alignment in the width direction (the sheet width direction orthogonal to the sheet conveyance direction). The hitting roller 12 is given a pendulum motion by the hitting SOL 170 about the fulcrum 12a, and intermittently acts on the sheet sent to the end-face binding processing tray F to abut the sheet rear end PT against the rear end reference fence 51. The hitting roller 12 itself rotates counterclockwise in the figure. The jogger fence 53 is provided with a pair of front and rear (53a, 53b) as shown in FIGS. 2 and 3, and is driven via a timing belt by a jogger motor 158 capable of forward / reverse rotation, and is symmetrically approached and separated in the seat width direction. So reciprocate.

  Returning to FIG. 1, a sheet bundle deflection mechanism is provided on the downstream side in the sheet conveyance direction of the end-face binding processing tray F. The conveying path for conveying the sheet bundle PB from the end-face stitching processing tray F to the saddle-stitching processing tray G, and from the end-face stitching processing tray F to the shift tray 202, and the conveying means for conveying the sheet bundle PB impart conveying force to the sheet bundle PB. A feeding mechanism 35 for feeding, a discharge roller 56 for turning the sheet bundle PB, and a guide member 44 for performing a guide for turning the sheet bundle PB.

  Each detailed configuration will be described. The driving force of the driving shaft 37 is transmitted to the roller 36 of the transport mechanism 35 by a timing belt. The roller 36 and the driving shaft 37 are connected and supported by an arm, and driven. The shaft 37 can be swung about the rotation fulcrum. The roller 36 of the transport mechanism 35 is driven to swing by a cam 40. The cam 40 rotates around a rotation shaft and is driven by a motor (not shown). In the transport mechanism 35, a driven roller 42 is disposed at a position opposite to the roller 36, the sheet bundle PB is sandwiched between the driven roller 42 and the roller 36, and is pressurized by an elastic material to give a transport force.

  A conveyance path for turning the sheet bundle PB from the end-face binding processing tray F to the saddle stitching processing tray G is formed between the discharge roller 56 and the inner surface of the guide member 44 facing the discharge roller 56. The guide member 44 rotates around a fulcrum, and the drive is transmitted from the bundle branch drive motor 161 (see FIG. 2). When the sheet bundle PB is conveyed from the end surface binding processing tray F to the shift tray 202, the guide member 44 rotates in the clockwise direction in the figure around the fulcrum, and the outer surface of the guide member 44 (on the side not facing the discharge roller 56). The space between the surface) and the guide plate outside thereof functions as a conveyance path. When the sheet bundle PB is sent from the end face binding processing tray F to the saddle stitching processing tray G, the trailing edge of the sheet bundle PB aligned on the end face binding processing tray F is pushed up by the discharge claw 52a, and the roller 36 of the transport mechanism 35 and this The sheet bundle PB is sandwiched between the opposed driven rollers 42 facing each other, and a conveying force is applied. At this time, the roller 36 of the transport mechanism 35 stands by at a position where it does not hit the leading end of the sheet bundle PB. Next, after the leading edge of the sheet bundle has passed, the roller 36 of the transport mechanism 35 is brought into contact with the sheet surface to apply a transport force. At this time, the guide member 44 and the discharge roller 56 form a guide for the turn conveyance path, and convey the sheet bundle PB to the downstream saddle stitching processing tray G.

  As shown in FIG. 1, the saddle stitch processing tray G is provided on the downstream side of the sheet bundle deflection mechanism including the conveyance mechanism 35, the guide member 44, and the discharge roller 56. The saddle stitching processing tray G is provided substantially perpendicularly on the downstream side of the sheet bundle deflection mechanism, with the center folding mechanism at the center, the bundle conveyance guide plate upper 92 above, and the bundle conveyance guide below. A lower plate 91 is arranged.

  Further, an upper bundle conveying roller 71 is provided above the upper bundle conveying guide plate 92, and a lower bundle conveying roller 72 is provided below the upper bundle conveying guide plate 92. A saddle stitch upper jogger fence 250a is arranged on both sides along the side surface of 92. Similarly, a saddle stitch lower jogger fence 250b is provided on both sides along the side surface of the bundle conveyance guide plate lower 91, and the saddle stitch stapler S2 is disposed at a place where the saddle stitch lower jogger fence 250b is installed. The saddle stitching upper jogger fence 250a and the saddle stitching lower jogger fence 250b are driven by a driving mechanism (not shown) and perform an alignment operation in a direction orthogonal to the sheet conveying direction (sheet width direction). The saddle stitching stapler S2 is a pair of a clincher portion and a driver portion, and two pairs are provided at a predetermined interval in the width direction of the sheet.

  In addition, a movable rear end reference fence 73 is disposed so as to cross the bundle conveyance guide plate lower 91, and can be moved in the sheet conveyance direction (vertical direction in the drawing) by a moving mechanism including a timing belt and its driving mechanism. Yes. As shown in FIG. 1, the drive mechanism includes a drive pulley and a driven pulley on which the timing belt is stretched, and a stepping motor that drives the drive pulley. Similarly, a rear end tapping claw 251 and its drive mechanism are provided on the upper end side of the upper bundle transport guide plate 92. The rear end tapping claw 251 can be reciprocated in a direction away from the sheet bundle deflection mechanism and a direction of pushing the rear end of the sheet bundle PB (the side hitting the rear end when the sheet bundle is introduced) by a timing belt 252 and a driving mechanism (not shown). It has become.

  The center folding mechanism is provided at a substantially central portion of the saddle stitching processing tray G, and includes a folding plate 74, a folding roller 81, and a conveyance path H that conveys the folded sheet bundle PB. In FIG. 1, reference numeral 326 denotes a home position sensor for detecting the home position of the rear end tapping claw 251, reference numeral 323 denotes a folded portion passage sensor for detecting a folded sheet, and reference numeral 321 denotes a sheet bundle PB. Bundle detection sensor 322 for detecting that has reached the center folding position, and reference numeral 322 is a movable rear end reference fence home position sensor for detecting the home position of movable rear end reference fence 73.

  In this embodiment, a detection lever 501 for detecting the stacking height of the sheet bundle PB folded in the lower tray 203 is provided to be swingable by a fulcrum 501a, and the angle of the detection lever 501 is determined by a paper surface sensor 505. Detecting and raising / lowering the lower tray 203 and detecting overflow.

  FIG. 5 is a perspective view of the main part showing the configuration of the paper discharge unit J of the sheet post-processing apparatus shown in FIG. In the figure, the paper discharge section J is mainly composed of a shift tray 202, a paper discharge roller pair 6, an auxiliary tray 13, and a lifting mechanism 14 that lifts and lowers the shift tray 202.

  The elevating mechanism 14 includes an elevating motor 14a, a reduction gear mechanism 14b for transmitting the driving force of the elevating motor 14a to the elevating belt 14c, and a drive pulley 14d provided coaxially with the final gear of the reduction gear mechanism 14b, as shown in FIG. And an endless elevating belt 14c stretched between a driven pulley 14e provided at a position lower than a predetermined height on the side surface of the sheet post-processing apparatus PD from the drive pulley 14d, and bases on both sides of the shift tray 202 202a is connected to a lifting belt 14c provided as a pair, and is lifted and lowered by the rotation of the motor 14a. The motor 14a is controlled by a CPU 101 described later.

  The auxiliary tray 13 is positioned below the sheet discharge outlet (the nip between the pair of sheet discharge rollers 6) and on the upper surface of the sheet discharge tray 202, and temporarily stacks sheets discharged to the sheet discharge tray 202 and relays them to the shift tray 202. Paper is discharged.

  As shown in the enlarged view of the paper discharge unit J in FIG. 6, the auxiliary tray 13 includes an auxiliary tray driving mechanism 400 that moves the auxiliary tray forward and backward, and an auxiliary tray belt 402 that moves following the movement of the auxiliary tray 13. ing. The auxiliary tray drive mechanism 400 includes an auxiliary tray drive motor 400a that is a drive source of the auxiliary tray drive mechanism 400, a pinion 400b that is provided coaxially with the drive shaft of the auxiliary tray drive motor 400a, and the auxiliary tray on the sheet post-processing apparatus main body side. An advancing and retreating operation is performed in a state of being supported by a first and second pair of guide shafts 411 and 412 provided at an end portion and including a rack 400c with which the pinion 400b meshes, and provided in a direction orthogonal to the sheet conveying direction. Is possible.

  One end side of the auxiliary tray belt 402 passes from the upper surface of the auxiliary tray 13 to the lower surface side through the tip portion (end portion on the downstream side in the sheet conveying direction) 13 a and passes between the second guide shaft 412 and the auxiliary tray 13. One auxiliary tray belt drive motor 401 is connected to a rotation shaft, and the other end is connected to a rotation shaft of a second auxiliary tray belt drive motor 403 disposed on the upper surface side of the auxiliary tray 12.

  FIG. 7 is an operation explanatory diagram showing an operation when the sheet P is discharged to the shift tray 202 side. As shown in FIG. 7, the sheet P guided to the outside by the paper discharge roller pair 6 is first stacked on the auxiliary tray 13. At this time, the auxiliary tray 402 is moved in the same direction D1 as the conveying direction at the same speed as the sheet P to which the auxiliary tray driving motor 400 is discharged every time the sheet is discharged, and the auxiliary tray belt 402 follows the movement. Stretch with. During this extension operation, the first and second auxiliary tray belt drive motors 401 and 403 rotate in the direction in which the auxiliary tray belt 402 is fed out. This operation is performed every time the sheet is discharged, and thereby, the contact position between the sheet P and the auxiliary tray belt 402 is stacked on the auxiliary tray 13 without changing. FIG. 8 is a diagram illustrating a state when the sheets P are stacked on the auxiliary tray 13.

Thereafter, the sheet P is moved from the auxiliary tray 13 to the shift tray 202 side. 9 and 10 are diagrams showing the operation at this time.
Before or during stacking of the sheets P on the auxiliary tray 13, the shift tray 202 detects the height of the sheet bundle PB stacked on the shift tray 202 by the paper surface detection sensor 330, and removes the sheet P from the auxiliary tray 13. To receive the sheet, the sheet is moved up to the sheet receiving position (in the direction of arrow D5). After the entire sheet P is stacked on the auxiliary tray 13 as shown in FIG. 8, the first auxiliary tray belt drive motor 401 is moved in the direction in which the auxiliary tray belt 402 is wound (direction of arrow D3) as shown in FIG. The second auxiliary tray belt drive motor 403 rotates to feed out the auxiliary tray belt 402, and the auxiliary tray drive motor 400 moves (retracts) the auxiliary tray 12 in the direction opposite to the conveying direction (arrow D4 direction). In parallel with this, when the auxiliary tray 13 is moved backward to the sheet post-processing apparatus PD main body side, the sheet P is lowered and stacked on the shift tray 202 as shown in FIG.

  FIG. 11 is a diagram illustrating an operation of aligning the sheets P stacked on the shift tray 202 in the state of FIG. The alignment is alignment in the sheet conveyance direction, and is an operation performed by the return roller in the above-described conventional technology. In this embodiment, an auxiliary tray belt 402 is used instead of the return roller. Therefore, the upper surface of the sheet P on the shift tray 202 is raised to a position where it contacts the auxiliary tray belt 402 (arrow D5 direction), and the auxiliary tray belt 402 is rotated in the direction opposite to the conveying direction (arrow D3 direction). The rotation directions of the first and second auxiliary tray belt drive motors 401 and 403 at this time are the same as when the sheet P is lowered onto the shift tray 202. In this way, the sheet P is moved in the direction opposite to the conveyance direction, the trailing edge of the sheet hits the end fence 210, and alignment in the sheet conveyance direction is performed.

  FIG. 12 is a block diagram illustrating a control configuration of an image forming system including the sheet post-processing apparatus PD and the image forming apparatus PR. The sheet post-processing apparatus PD includes a control circuit on which a microcomputer having a CPU 101, an I / O interface 102, and the like is mounted. The CPU 101 includes a CPU of the image forming apparatus PR or switches of the operation panel 105, and sensors (not shown). Is input via the communication interface 103, and the CPU 101 executes predetermined control based on the input signal. Further, the CPU 101 drives and controls a solenoid and a motor via a driver and a motor driver, and acquires sensor information in the apparatus from the interface. In addition, motor drive control is performed by the motor driver via the I / O interface 102 in accordance with the control target and sensor, and sensor information is acquired from the sensor. The control is based on a program defined by the program code while the CPU 101 reads a program code stored in a ROM (not shown), expands it in a RAM (not shown), and uses the RAM as a work area and a data buffer. Executed.

  Further, the control of the sheet post-processing apparatus PD in FIG. 12 is executed based on an instruction or information from the CPU of the image forming apparatus PR. User operation instructions are issued from the operation panel 105 of the image forming apparatus PR, and the image forming apparatus PR and the operation panel 105 are connected to each other via a communication interface 106. As a result, an operation signal from the operation panel 105 is transmitted from the image forming apparatus PR to the sheet post-processing apparatus PD, and the processing state and functions of the sheet post-processing apparatus PD are transmitted to the user or the operator via the operation panel 105 Be notified.

  Accordingly, when a paper type that needs to use the auxiliary tray 13 is selected from the operation panel 105 of the image forming apparatus PR, or when the user directly selects the use of the auxiliary tray 13, the CPU of the image forming apparatus PR performs the sheet post-processing apparatus. The CPU 101 of the PD is instructed to use the auxiliary tray 13, and the sheet post-processing apparatus PD repeats the advance / retreat operation of the auxiliary tray 13, the sheet transfer operation to the shift tray 202, and the alignment operation for each designated sheet, A target sheet is stacked on the shift tray 202.

  At this time, the sheet P is discharged to the auxiliary tray 13, and the sheet is conveyed to the upper side of the shift tray 202 (a position with a high inclined surface on the downstream side in the conveyance direction) by the traveling operation of the auxiliary tray belt 402. Since the sheet moves in the direction opposite to the conveying direction, the leading edge of the sheet P does not hit the upper surface of the sheet P on the shift tray 202, and the lower surface side of the leading edge of the sheet P is soft on the upper surface of the sheet P on the shift tray 202. Loaded in contact. At that time, since the time until the discharged sheet P comes into contact with the already stacked sheets P becomes longer, the sheet P does not buckle. Further, the auxiliary tray 13 does not come into contact with the upper surface of the already stacked sheets. Therefore, the sheets P are stacked in a surely aligned state.

  That is, the sheets P are transferred from the auxiliary tray 13 onto the shift tray 202 with a very small moving distance, and then aligned by the auxiliary tray belt 402 on the sheet P or the sheet bundle PB one by one. Since the stacking is completed when the alignment is completed, the sheet P is not stuck and buckled for the reason described above, and the sheets can be aligned and stacked regardless of the presence or absence of curling.

  In this embodiment, the sheet in the claims to be described later is denoted by symbol P, the stacking means is the shift tray 202, the discharge means is the discharge roller pair 6, the lifting means is the lifting mechanism 14, and the temporary stacking means is In the auxiliary tray 13, the advancing / retracting driving means is in the auxiliary tray driving mechanism 400, the movement alignment means is in the auxiliary tray belt 402, the first and second auxiliary tray belt driving motors 401 and 403, the control means is in the CPU 101, and the sheet processing. The apparatus corresponds to the sheet post-processing apparatus PD, the image forming apparatus corresponds to PR, and the image forming system corresponds to a system including the sheet post-processing apparatus PD including the shift tray 202 and the image forming apparatus PR.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and all the technical matters included in the technical idea described in the claims are all included. The subject of the present invention. The above embodiment shows a preferable example, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the content disclosed in this specification, These are included in the technical scope described in the appended claims.

6 Paper discharge roller pair 13 Auxiliary tray 14 Lifting mechanism 101 CPU
202 shift tray 400 auxiliary tray drive mechanism 401 first auxiliary tray belt drive motor 402 auxiliary tray belt 403 second auxiliary tray belt drive motor P sheet PD sheet post-processing device PR image forming apparatus

JP-A-10-324449

Claims (10)

A stacking means for stacking sheets;
Paper discharge means for discharging the conveyed sheet onto the stacking means;
Elevating means for elevating and lowering the loading means;
Temporary stacking means for temporarily stacking the sheets discharged by the paper discharge means before moving them onto the stacking means;
Advancing and retreating driving means for advancing and retreating the temporary loading means on the loading means;
A movement aligning means that is arranged along the upper and lower surfaces of the temporary stacking means, controls movement of the sheet in conjunction with the advance and retreat operation of the temporary stacking means, and aligns the sheet;
Sheet stacking device with The sheet stacking apparatus according to claim 1,
The movement alignment means includes
When the sheet is discharged, the temporary stacking unit is advanced onto the stacking unit and the moving alignment unit is moved in the sheet conveying direction.
When the sheet is stacked on the stacking unit, the temporary stacking unit is retracted from the stacking unit,
The sheet stacking apparatus, wherein when the sheets are aligned, the stacking unit is moved up by the elevating unit and the sheet is brought into contact with the moving alignment unit to move the sheet in a direction opposite to the sheet conveying direction. The sheet stacking apparatus according to claim 1 or 2,
The advancing / retracting driving means advances the temporary stacking means at the same speed as a discharge speed of the sheet discharged by the discharge means. The sheet stacking apparatus according to claim 3,
When the temporary stacking unit advances, the movement aligning unit moves in the direction of discharging the sheet along the upper surface of the temporary stacking unit at the same speed as the discharge speed. . The sheet stacking apparatus according to claim 3,
When the temporary stacking unit moves backward, the movement alignment unit moves in the direction of discharging the sheet along the upper surface of the temporary stacking unit at the same speed as the retraction speed of the position stacking unit. Sheet stacking device. The sheet stacking apparatus according to any one of claims 1 to 5,
A sheet stacking apparatus comprising control means for controlling the operation of the movement alignment means. The sheet stacking apparatus according to any one of claims 1 to 6,
Further comprising detection means for detecting the front of the sheets stacked on the stacking means;
The sheet stacking apparatus according to claim 1, wherein the lifting position of the stacking means by the lifting means is set based on a detection result of the detection means. The sheet stacking apparatus according to any one of claims 1 to 7,
The sheet stacking apparatus according to claim 1, wherein the movement aligning means comprises a belt-like member.   A sheet processing apparatus comprising the sheet stacking apparatus according to claim 1.   An image forming system comprising the sheet stacking apparatus according to claim 1.