JP2005350188A - Sheet stacking device and image forming device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent sheets stacked on a sheet stacking means from being flown off by a wind or their stacked condition from being disturbed. <P>SOLUTION: A sheet stacking device 400 is equipped with: an upper stacking tray 18 able to rise and fall whereon sheets are to be stacked; an upper elevating/sinking device 66 to elevate and sink the tray; a sheet sensor S7 to sense the sheets stacked on the tray; a CPU 510 to control the upper elevating/sinking device on the basis of the sheet sensing operation of the sheet sensor and thereby put the uppermost one of the stacked sheets at the specified level; and an upper paddle 17 to hold down the top surface of the stacked sheets. With this sheet stacking device in which the upper paddle 17 holds down the top surface of the stacked sheets, the sheets are prevented from being flown off by the cold or hot wind of a cooling/heating apparatus, cooling wind flowing out of an OA business machine, or the wind generated at passage of a person, etc. or their stacked condition from being disturbed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  In the present invention, a sheet on a sheet stacking unit on which sheets are stacked is blown by, for example, cool air or warm air from an air conditioning apparatus, cooling air flowing out from the OA office machine, or wind generated when a person passes. The present invention relates to a sheet stacking apparatus that does not disturb or disturb the image stacking apparatus and an image forming apparatus that includes the sheet stacking apparatus in the apparatus main body.

  Examples of the image forming apparatus that forms an image on a sheet include a copying machine, a printer, a facsimile, and a complex machine of these. In some cases, the image forming apparatus includes a sheet stacking device on which discharged sheets are stacked.

  In addition, the sheet stacking device loads sheets that are forcibly stacked on the basis of sheet size or stacking number information in order to stabilize the stacking state of sheets being stacked on the sheet stacking means in a short time. Some are controlled to be pressed down (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 9-100060

  However, the pressing mechanism of the conventional sheet stacking device selectively selects the sheet being stacked depending on the sheet size and the number of stacked sheets in order to prevent disturbance of the stacking state due to the curl direction and size of the stacked sheet. Usually, the sheet pressing member is opened from the top of the sheet. In addition, the pressing mechanism is simply configured to press the discharged sheet from above, and has no function of positively aligning. For this reason, the sheets stacked in the sheet stacking means on which the discharged sheets are stacked are generated when, for example, the cool air or warm air of the air conditioning equipment, the cooling air flowing out of the OA office machine, or a person passes. The wind may be blown away or the loading condition may be disturbed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet stacking apparatus in which sheets stacked on a sheet stacking unit are not blown off by a wind or a stacking state is not disturbed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes the sheet stacking apparatus and can increase the image forming efficiency.

  In order to achieve the above object, a sheet stacking apparatus according to the present invention includes a sheet stacking unit capable of moving up and down on which sheets are stacked, a sheet lifting unit for moving up and down the sheet stacking unit, and the sheet stacked on the sheet stacking unit. A sheet detecting means for detecting the sheet, and the sheet raising and lowering means based on the sheet detecting operation of the sheet detecting means, so that the uppermost sheet among the sheets stacked on the sheet stacking means has a predetermined height. Control means for positioning the sheet, and sheet pressing means for pressing the upper surface of the sheet stacked on the sheet stacking means.

  The sheet stacking apparatus of the present invention includes a sheet aligning unit that aligns at least one side end along the sheet conveying direction of the sheet stacked on the sheet stacking unit, and the sheet aligning unit includes the sheet pressing unit When the sheet is pressing the sheet, the sheet is positioned to align.

  In the sheet stacking unit of the present invention, the sheet pressing unit has a function of transporting the sheet stacked on the sheet stacking unit to the upstream side in the sheet transport direction, and is transported to the upstream side by the sheet pressing unit. And stopper means for receiving the upstream end of the sheet.

  In order to achieve the above object, an image forming apparatus according to the present invention includes: an image forming unit that forms an image on a sheet; and a sheet stacking device on which the sheet on which an image is formed by the image forming unit is stacked. The sheet stacking apparatus is the sheet stacking apparatus according to any one of the above.

  In order to achieve the above object, an image forming apparatus of the present invention includes an image forming unit that forms an image on a sheet, a sheet stacking unit that can move up and down on which the sheet on which an image is formed by the image forming unit, Controlling the sheet elevating means based on the sheet detection operation of the sheet detecting means, the sheet detecting means for detecting the sheet stacked on the sheet stacking means, Control means for positioning the uppermost sheet among the sheets stacked on the sheet detecting means at a predetermined height position, and sheet pressing means for pressing the upper surface of the sheets stacked on the sheet stacking means And.

  In the sheet stacking apparatus of the present invention, the control unit controls the sheet lifting device based on the sheet detecting operation of the sheet detecting unit, so that the uppermost sheet among the sheets stacked on the sheet detecting unit has a predetermined height. The sheet pressing means can hold the sheet under the same conditions regardless of the number of sheets stacked on the sheet stacking means. It can be prevented from being blown or disturbed by wind, cooling air flowing out of the office machine, or wind generated when a person passes.

  In the sheet stacking apparatus of the present invention, when the sheet aligning unit is positioned to align the sheet when the sheet pressing unit is pressing the sheet, it is ensured that the sheet stacking unit is not affected by the wind. Can do.

  The sheet stacking apparatus according to the present invention is configured to receive the sheet with the stopper unit while conveying the sheet to the upstream side in the sheet conveying direction by the sheet pressing unit, and thus can prevent the upstream end of the sheet from being disturbed by wind.

  The image forming apparatus of the present invention includes a sheet stacking apparatus that can stack sheets without being affected by wind. Therefore, the image formed sheets can be discharged smoothly, and the image forming efficiency can be improved. Can be increased.

  Hereinafter, a sheet stacking apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet stacking apparatus in an apparatus main body will be described with reference to the drawings.

  FIG. 1 is a schematic front sectional view of a copying machine as an example of an image forming apparatus provided with a sheet stacking apparatus of the present invention in an apparatus main body. Examples of the image forming apparatus include a copying machine, a facsimile, a printer, and a complex machine of these. Therefore, the sheet stacking apparatus of the present invention is connected to an apparatus other than the apparatus main body of the copying machine. The sheet stacking apparatus is connected to the outside of the image forming apparatus main body, but may be incorporated in the apparatus main body.

(Copier)
The copier 501 includes a reader unit 100, a printer unit 200, a sheet stacking device 400, and the like. An ADF 300 that supplies originals one by one onto the platen glass 102 is provided at the top of the copier 501. The ADF 300 is not necessarily provided, and the user may place the document directly on the platen glass 102. A sheet stacking apparatus 400 that can stack sheets discharged from the apparatus main body 501A of the copying machine 501 is connected to the side of the apparatus main body 501A of the copying machine 501.

  The reader unit 100 converts a document into image data. The printer unit 200 has a plurality of types of sheet cassettes 204 and 205 on which a plurality of sheets are stacked, and forms image data as a visible image on a sheet by a print command.

  The reader unit 100 uses an automatic document feeder (hereinafter referred to as “ADF”) 300 to convey and pass a document to a predetermined position on the platen glass 102 while stopping the scanner unit 104 at the predetermined position. The light of the lamp 103 of the scanner unit 104 is irradiated to the original or the user opens the ADF 300 and the original placed on the plantain glass 102 is irradiated with the light of the lamp 103 of the scanner unit 104 moved in the left-right direction. .

  The reflected light from the document is input to the CCD image sensor unit 109 through the mirrors 105, 106, 107 and the lens 108. The reflected light of the original irradiated to the CCD image sensor unit 109 is subjected to electrical processing such as photoelectric conversion in the CCD image sensor unit 109 and is subjected to normal digital processing. Thereafter, these image signals are input to the printer unit 200.

  The image signal input to the printer unit 200 is modulated by the exposure control unit 201 and converted into an optical signal, and irradiates, for example, a photoconductor 202 that is an image forming unit. The latent image formed on the photosensitive member 202 by the irradiation light is developed with toner by the developing unit 203 to become a toner image. Then, in synchronization with the leading edge of the toner image, the sheet is conveyed from one of the sheet cassettes 204 and 205, and the toner image is transferred to the sheet by the transfer unit 206. The transferred toner image is fixed on the sheet by the fixing unit 207. The sheet on which the toner image is fixed passes through a path 214 and is discharged from the sheet discharge unit 208 to the outside of the apparatus main body 501A of the copier 501. Thereafter, the sheets are stacked on a sheet stacking apparatus 400 that can be stacked so as not to be blown by wind.

(Sheet stacker)
A sheet stacking apparatus 400 shown in FIGS. 1 and 2 is provided on the side portion of the apparatus main body 501A of the copying machine 501, for example, an upper stacking tray 18, which is a sheet stacking unit, an upper sheet transport discharge path 62, a sheet. For example, a lower stacking tray 37 as a stacking unit, and a lower sheet conveyance / discharge path 63 are provided.

(Mechanism to convey the sheet through the upper sheet conveyance path)
A timing belt 5 is stretched between the rotation shaft of the conveyance drive motor 6 that is started by the operation of the inlet sensor S1 and the connection gear 4. A timing belt 3 is stretched between the connecting gear 4 and the upper entrance roller 1. A driven roller 2 is in pressure contact with the upper entrance roller 1. A timing belt 8 is stretched between the discharge drive motor 7 and the connecting gear 9. The timing belt 10 is stretched over the connecting gear 9, the upper discharge roller 11, and the idler pulley 64. A timing belt 29 is stretched between the upper discharge roller 11 and the lower discharge roller 30. A driven roller 12 is in pressure contact with the upper discharge roller 11. The timing belt 10 is also stretched over the upper knurled belt driving roller 90, and the upper knurled belt 19 is driven by the upper knurled belt driving roller 90.

  The sheet conveyed through the upper sheet conveying / discharging path 62 includes an upper inlet roller 1 and a driven roller 2 that are rotated by driving of the conveying driving motor 6, an upper discharging roller 11 that is rotated by driving of the discharging driving motor 7, and It is conveyed by the driven rollers 12 and discharged to the upper stacking tray 18.

  An inlet sensor S1 is disposed on the upstream side of the upper entrance roller 1. The entrance sensor S1 detects the leading edge and trailing edge of the sheet sent from the apparatus main body 501A of the copying machine 501 to the sheet stacking apparatus 400. A flapper 13 is disposed near the downstream side of the inlet sensor S1. The flapper 13 can change the sheet conveying direction to one of the upper stacking tray 18 and the lower stacking tray 37 by a driving solenoid 14.

  On the upstream side of the upper paper discharge roller 11, an upper paper discharge sensor S2 is provided. The upper sheet discharge sensor S2 detects the leading edge and trailing edge of the conveyed sheet. The upper stacking tray 18 is provided with a sheet detection sensor S7 which is an example of a sheet detecting unit that detects whether or not a sheet is stacked on the upper stacking tray 18.

  When the sheet is discharged from the upper discharge roller 11, the upper discharge sensor S2 detects the trailing edge of the sheet. Based on the sheet detection operation of the upper sheet discharge sensor S2, the upper paddle motor 16 is started and the upper paddle 17 starts to rotate. At this time, the trailing edge of the sheet has already passed through the upper paper discharge roller 11. The upper paddle 17 is fed between, for example, a plurality of upper knurled belts 19 and the upper stacking tray 18 as a regulation holding unit that regulates a sheet dropped on the upper stacking tray 18 as an alignment reference for sheet shifting. The upper knurled belt 19 has already been rotated together with the upper sheet discharge roller 11 by the timing belt 10, and the sheet is brought into contact with, for example, the stacking wall portion 20 serving as a stopper unit to align the rear end of the sheet. Since the seat is in the vicinity of the upper knurled belt 19, the seat is reliably pulled in and the rear end portion is aligned. Thereafter, the aligning operation of the end along the sheet conveyance direction, that is, the side end of the sheet is performed. The side edge alignment operation will be described later. The alignment of the rear end portion of the sheet may be performed after the alignment of the side end portion of the sheet. The configurations of the upper paddle motor 16, the upper paddle 17, the upper knurl belt 19 and the like are examples of sheet pressing means. The upper knurled belt 19 is not always necessary.

(Mechanism for conveying the sheet through the lower sheet conveyance path)
A timing belt 5 is stretched between the rotation shaft of the conveyance drive motor 6 that is started by the operation of the inlet sensor S1 and the connection gear 4. A plurality of lower entry rollers 21 and driven rollers 22 driven by the lower entry rollers 21 are rotated by the rotation of the connecting gear 4. A timing belt 23 is wound around the lower entrance roller 21 and the plurality of vertical path first rollers 24. A driven roller 25 that is driven and rotated is in pressure contact with the vertical path first roller 24. A timing belt 26 is stretched between the vertical path first roller 24 and the vertical path second roller 27. A driven roller 28 that is driven and rotated is in pressure contact with the vertical path second roller 27. A timing belt 29 is stretched between the upper discharge roller 11 and the lower discharge roller 30. A driven roller 31 that is driven and rotated is pressed against the plurality of lower discharge rollers 30. Further, a timing belt 35 is stretched over the lower discharge roller 30, the idler pulley 65 and the lower knurl belt driving roller 99, and the lower knurl belt 36 is driven by the lower knurl belt driving roller 99.

  A sheet conveyed through the lower sheet conveying discharge path 63 is pressed against the lower inlet roller 21, the vertical path first roller 24, the vertical path second roller 27, and the respective rollers which are rotated by driving of the conveyance drive motor 6. The driven rollers 22, 25, and 28, and the lower discharge rollers 30 and the driven rollers 31 that are rotated by the discharge drive motor 7 are conveyed to the lower stack tray 37.

  Between the lower entrance roller 21 and the vertical path first roller 24, a vertical path first sensor S3 is disposed. Between the vertical path first roller 24 and the vertical path second roller 27, a vertical path second sensor S4 is disposed. Between the vertical path second roller 27 and the lower discharge roller 30, a lower discharge sensor S5 is disposed. These sensors S3, S4, and S5 detect the leading edge and the trailing edge of the sheet. The lower stacking tray 37 is also provided with a sheet detection sensor S8 which is an example of a sheet detecting unit that detects whether or not sheets are stacked on the lower stacking tray 37.

  When the lower sheet discharge sensor S5 detects the trailing edge of the sheet, the lower paddle motor 33 is started and the lower paddle 34 starts to rotate. At this time, the trailing edge of the sheet has already passed through the lower paper discharge roller 30. The lower paddle 34 feeds, for example, between a plurality of lower knurled belts 36 and the lower stacking tray 37 as a regulation holding unit that regulates a sheet dropped on the lower stacking tray 37 as an alignment reference for sheet shifting. The lower knurl belt 36 has already been rotated together with the lower paper discharge roller 30 by the timing belt 35 spanned between the lower paper discharge roller 30 and the idler pulley 65, and for example, a sheet as a stopper means is pushed against the stacking wall 38. Align and align the trailing edge of the sheet. Since the seat is in the vicinity of the lower knurled belt 36, the seat is reliably pulled in and the rear end portion is aligned. Thereafter, the aligning operation of the end along the sheet conveyance direction, that is, the side end of the sheet is performed. The side edge alignment operation will be described later. The alignment of the trailing edge of the sheet may be performed after the alignment of the side edge of the sheet. The configurations of the lower paddle motor 33, the lower paddle 34, the lower knurl belt 36, and the like are examples of sheet pressing means. The lower knurled belt 36 is not always necessary.

  The sheet stacking apparatus 400 according to the present embodiment performs an offset mode discharge process in addition to a normal discharge mode when discharging sheets to the upper stack tray 18 and the lower stack tray 37.

  In the offset mode, the upper sheet discharge roller 11 and the driven roller 12 sandwich the sheet, or the lower sheet discharge roller 30 and the driven roller 31 intersect the sheet conveyance direction with the sheet interposed therebetween (sheet width direction). ) And the sheet is shifted in the width direction and discharged. The driven rollers 12 and 31 are moved via the sheet as the upper and lower discharge rollers 11 and 30 move.

(Movement device for upper discharge roller)
A discharge roller moving device 77 for moving the upper discharge roller 11 in the sheet width direction will be described with reference to FIG. The upper discharge roller 11 is provided integrally with the rotation shaft 71. The rotating shaft 71 is supported by a bearing (not shown) and disposed in a direction orthogonal to the sheet conveying direction. The rotating shaft 71 is rotatably supported by a bearing (not shown) so as to be movable in the thrust direction (arrows A and B directions (sheet width direction)). The rotating shaft 71 passes through the pulley 72. The pulley 72 is rotatably supported by a support member (not shown) so as to be restricted from moving in the thrust direction. The timing belt 10 is hung on the pulley 72. The pulley 72 is configured to transmit rotation to the rotating shaft 71 by circulation of the timing belt 10. For this reason, a spline groove is formed in the inner diameter of the pulley 72, and a part of the rotary shaft 71 is a spline shaft. That is, the pulley 72 and the rotating shaft 71 are coupled by a so-called spline mechanism. As a result, the rotating shaft 71 can be rotated by receiving the rotational force of the pulley 72 and can be offset in the thrust direction.

  In a part of the outer periphery of the rotating shaft 71, a plurality of grooves 73 along the rotational direction are formed along the thrust direction. A worm gear 74 is engaged with the groove 73. The worm gear 74 is rotated by a discharge roller moving motor 76 via a timing belt 75.

  Therefore, the upper discharge roller 11 is offset by the rotation of the discharge roller moving motor 76 while being rotated by the rotation of the pulley 72 while the conveyed sheet is sandwiched between the driven rollers 12. Thus, the sheet is discharged near a left alignment plate 40 or a right alignment plate 39 described later. The discharge roller moving motor 76, the timing belt 75, the worm gear 74, the rotating shaft 71 and the like constitute a discharge roller moving device 77.

  The lower discharge roller 30 is also moved in the width direction of the sheet by a discharge roller moving device similar to the discharge roller moving device 77, and illustration and description thereof are omitted.

(Left alignment plate offset device)
The left alignment plate 40 moves in the direction of arrow B to align the left end of the sheet. A timing belt 93 is hung on the left alignment plate driving motor 42 and a pulley 92 integral with the pinion 91. The pinion 91 meshes with a rack 94 that is integral with the left alignment plate 40. The position of the solid left alignment plate 40 shown in FIG. 4 is the home position. The position is detected by shielding the detection portion of the home position sensor S6b provided on the main body with the detection plate 1b provided on the left alignment plate 40. The left alignment plate driving motor 42, the timing belt 93, the pulley 92, the pinion 91, the rack 94, and the like constitute a left offset device 80 of the left alignment plate 40. The configuration including the left offset device 80 and the left alignment plate 40 is an example of a sheet alignment unit.

  Therefore, when the left alignment plate driving motor 42 rotates, the left alignment plate 40 rotates the pinion 91 via the timing belt 93 and the pulley 92, and the rack 94 moves in the direction of arrow B. The left end can be aligned.

(Offset device for right alignment plate)
The right alignment plate 39 is moved in the direction of arrow A to align the right end of the sheet. A timing belt 83 is hung on the right alignment plate driving motor 41 and the pulley 82 integrated with the pinion 81. The pinion 81 meshes with a rack 84 that is integral with the right alignment plate 39. The position of the solid right alignment plate 39 shown in FIG. 4 is the home position. The position is detected by shielding the detection unit with a home position sensor S6a provided on the main body of the detection plate 1a provided on the right alignment plate 39. The right alignment plate driving motor 41, the timing belt 83, the pulley 82, the pinion 81, the rack 84, and the like constitute a right offset device 70 for the right alignment plate 39. The configuration including the right offset device 70 and the right alignment plate 39 is an example of a sheet alignment unit.

  Therefore, when the right alignment plate driving motor 41 rotates, the right alignment plate 39 rotates the pinion 81 via the timing belt 83 and the pulley 82, and the rack 84 moves in the direction of arrow A. The right end can be aligned.

(Upper lifting device for upper stacking tray)
As shown in FIG. 2, the base of the upper stacking tray 18 of the upper lifting device 66, which is an example of a sheet lifting / lowering unit that lifts and lowers the upper stacking tray 18, is fixed on the upper tray base 44. Upper guide rollers 46 and 47 are rotatably attached to the upper tray table 44. The guide rollers 46 and 47 are engaged with a vertically long upper guide rail 60. An upper timing belt 54 is connected to the upper tray base 44. The upper timing belt 54 circulates by receiving the rotational force of the upper tray motor 56 via the timing belt 58, the worm gear 50, and the worm wheel 51.

  Therefore, in the upper stacking tray 18, the upper tray motor 56 rotates, the upper timing belt 54 circulates, and the upper tray base 44 moves up and down by the guidance of the upper guide rail 60 and the guide rollers 46 and 47. The upper tray base 44 is moved up and down integrally.

  In this case, the upper stacking tray 18 is configured such that the uppermost sheet among the sheets stacked on the upper stacking tray 18 is positioned at a position where the uppermost sheet can be detected by, for example, the sheet detection sensor S7, which is a sheet detection unit. It is preferable that the rotation is controlled by rotating 56 so as to be stopped. In this case, the sheet is smoothly discharged from between the upper discharge roller 11 and the driven roller 12 without being obstructed by the sheets already stacked on the upper stack tray 18.

(Lower lifting device for lower stacking tray)
As shown in FIG. 2, a lower lift device 67, which is an example of a sheet lift device that lifts and lowers the lower stack tray 37, has the same mechanism as the upper lift device 66 of the upper stack tray 18. That is, the base of the lower stacking tray 37 of the lower lifting device 67 of the lower stacking tray is fixed below the lower tray base 45. Lower guide rollers 48 and 49 are rotatably attached to the lower tray base 45. The guide rollers 48 and 49 are engaged with the vertically long lower guide rail 61. A lower timing belt 55 is connected to the lower tray base 45. The lower timing belt 55 circulates by receiving the rotational force of the lower tray motor 57 via the timing belt 59, the worm gear 52, and the worm wheel 53.

  Therefore, in the lower stacking tray 37, the lower tray motor 57 rotates, the lower timing belt 55 circulates, and the lower tray base 45 is moved up and down by the guide of the lower guide rail 61 and the guide rollers 48 and 49. The lower tray base 45 is moved up and down integrally.

  In this case, the upper stacking tray 37 has a lower tray motor at a position where the uppermost sheet among the sheets stacked on the upper stacking tray 37 can be detected by, for example, a sheet detection sensor S8 which is a sheet detecting unit. By rotating and controlling 57, it is raised and lowered to stop. As a result, the sheet is smoothly discharged from between the upper sheet discharge roller 30 and the driven roller 31 without being obstructed by the sheets already stacked on the upper stack tray 37.

(Control unit of sheet stacking device)
FIG. 7 is a control block diagram of the sheet stacking apparatus 400.

  A control unit 520 (see FIG. 1) in the apparatus main body 501A of the copier 501 receives a command relating to sheet handling after image formation as a CPU 510 (central processing unit) that is an example of a control unit of the sheet stacking apparatus 400. To be sent to. The CPU 510 of the sheet stacking apparatus 400 returns status information and the like to the control unit 520 in the apparatus main body 501A of the copying machine. Exchange of these signals is performed via the interface controller 511. Although the control unit 520 and the CPU 510 are separate, they may be provided integrally with either the apparatus main body 501 or the sheet stacking apparatus 400.

  The ROM 512 stores a control program and the like corresponding to a sheet discharge operation sequence and a sheet alignment operation sequence of a sheet stacking apparatus 400 described later. The RAM 514 stores information necessary for executing the operation, and is used as a working memory. The EEPROM 515 is a non-volatile memory that stores device-specific parameters or information used continuously.

  The input port of the CPU 510 includes an inlet sensor S1, an upper discharge sensor S2, a first vertical path sensor S3, a second vertical path sensor S4, a lower discharge sensor S5, a home position sensor S6a, a home position sensor S6b, and a sheet detection sensor. S7 and the sheet detection sensor S8 are electrically connected.

  The output port of the CPU 510 includes a transport drive motor 6, a discharge drive motor 7, an upper paddle motor 16, a lower paddle motor 33, a right alignment plate drive motor 41, a left alignment plate drive motor 42, an upper tray motor 56, and a lower step. A tray motor 57, a discharge roller moving motor 76, other motors and solenoids 14, other solenoids, and the like are electrically connected.

  The CPU 510 includes information from the control unit 420 of the apparatus main body 501A, a control program stored in the ROM 512, information necessary for execution of operations stored in the RAM 514 and the EEPROM 515, and input / output ports (I / O) 516 and 517. Based on the detection signals of the sensors S1 to S8 that can be read out almost in real time via a drive unit (driver circuit) 518, a conveyance drive motor 6, a discharge drive motor 7, an upper paddle motor 16, and a lower stage Paddle motor 33, right alignment plate drive motor 41, left alignment plate drive motor 42, upper tray motor 56, lower tray motor 57, discharge roller moving motor 76, drive of other motors, solenoid 14, other solenoids Etc. are driven and controlled.

(Sheet alignment operation of sheet stacker)
As shown in FIG. 4, the sheet P <b> 1 is sent with the center CL <b> 1 in the width direction of the sheet aligned with the center CL <b> 2 in the width direction of the sheet conveyance / discharge path 62, and the upper sheet discharge roller 11 and the driven roller 12 ( 2) and is discharged to the upper stacking tray 18. The CPU 510 controls the left offset device 80 to move the left alignment plate 40 in the direction of arrow B, and controls the right offset device 70 to move the right alignment plate 39 in the direction of arrow A so that both sides of the sheet Align the edges. The moving distance of the left and right alignment plates 40 and 39 is set according to the width size of the sheet P1. In FIG. 4, the positions indicated by the solid lines of the left and right alignment plates 40, 39 are home positions, and the positions indicated by the broken lines are alignment positions.

  When aligning the left end of the sheet, it is as shown in FIG. That is, when the sheet P1 is sent with the center in the width direction aligned with the center in the width direction of the sheet conveyance / discharge path 62, the CPU 510 controls the discharge roller moving device 77 to control the upper discharge roller 11. Then, the sheet P1 sandwiched between the driven rollers 12 (see FIG. 2) is moved in the direction of arrow A and discharged to the upper stacking tray 18. Thereafter, the CPU 510 controls the left offset device 80 to move the left alignment plate 40 from the home position indicated by the broken line to the alignment position indicated by the solid line, thereby aligning the left end portion of the sheet P1.

  In this way, the alignment of the side edges of the sheets is often performed when aligning sheets P1, P2, and P3 having different width sizes as shown in FIG. In this case, the right alignment plate 39 aligns the right end portion of the maximum width size sheet P3.

  When the right end of the sheet is aligned, the state is as shown in FIG. Further, since the sheets stacked on the lower stacking tray 37 are aligned by the same operation, the description of the operation is omitted.

(Sheet pressing operation by upper paddle)
When sheets are stacked on the stacking tray 18 and aligned as described above, the CPU 510 controls the rotation of the upper paddle motor 16 as shown in FIG. 3 so that the upper paddle 17 is moved from the position indicated by the broken line to the solid line. The sheet P stacked on the stacking tray 18 is pressed from above. Thereby, it is possible to prevent the air from being blown or disturbed by the cold air or warm air of the air conditioning equipment, the cooling air flowing out of the OA office machine, or the wind generated when a person passes.

  In this case, the left and right alignment plates 40 and 39 are moved to the alignment position to cover both side end portions of the sheet, thereby further reliably preventing the wind from being blown or disturbed by the wind. Can do.

  Note that the upper stacking tray 18 shown in FIG. 3 may stop at a position where the uppermost sheet among the sheets stacked on the upper stacking tray 18 can be detected by the sheet detection sensor S7. In this case, regardless of the number of sheets stacked on the upper stacking tray 18, the upper paddle 17 can press the sheets under the same conditions, and the turbulence due to the wind can be surely prevented.

(Sheet pressing operation by the lower paddle)
The sheets stacked on the lower stacking tray 37 are also surely pressed onto the lower stacking tray 37 by the lower paddle 34. Since the pressing operation of the sheets stacked on the lower stacking tray 37 is the same as the pressing operation of the sheets stacked on the upper stacking tray 18, the description of the operation is omitted.

1 is a schematic front sectional view of a copying machine which is an example of an image forming apparatus provided with a sheet stacking apparatus of the present invention in an apparatus main body. 1 is a schematic front sectional view of a sheet stacking apparatus according to an embodiment of the present invention. FIG. 3 is a state diagram in which a sheet is pressed by a paddle in the sheet stacking apparatus of FIG. 2. FIG. 6 is a plan view of the periphery of the upper sheet discharge roller in the sheet stacking apparatus according to the embodiment of the present invention. FIG. 5 is a plan view of a sheet stacking apparatus in which left end portions of sheets are aligned with a left alignment plate in the sheet stacking apparatus illustrated in FIG. 4. FIG. 5 is a plan view of the sheet stacking apparatus in which the right end portion of the sheet is aligned with the right alignment plate in the sheet stacking apparatus illustrated in FIG. 4. It is a control block diagram in the sheet stacking apparatus of the embodiment of the present invention.

Explanation of symbols

S1 entrance sensor S2 upper sheet discharge sensor S3 vertical path first sensor S4 vertical path second sensor S5 lower sheet discharge sensor S6a home position sensor S6b home position sensor S7 sheet detection sensor (sheet detection means)
S8 Sheet detection sensor (sheet detection means)
P1 sheet P2 large width sheet P3 small width sheet CL1 sheet width center CL2 sheet conveyance discharge path width center 1 upper stage entrance roller 1a detection plate 1b detection plate 7 discharge drive motor 11 upper stage discharge roller 12 driven roller 16 upper stage Paddle motor (sheet holding means)
17 Upper paddle (sheet holding means)
18 Upper stack tray (sheet stacking means)
19 Upper knurled belt (sheet holding means)
20 Sheet stacking wall (stopper means)
30 Lower discharge roller 31 Follower roller 33 Lower paddle motor (sheet pressing means)
34 Lower paddle (sheet holding means)
36 Upper knurled belt (sheet holding means)
37 Lower stacking tray (sheet stacking means)
38 Sheet stacking wall (stopper means)
39 Right alignment plate (sheet alignment means)
40 Left alignment plate (sheet alignment means)
41 motor for driving right alignment plate 42 motor for driving left alignment plate 62 upper sheet conveyance path 63 upper sheet conveyance path 66 upper lifting device (sheet lifting means)
67 Lower lifting device (seat lifting means)
70 Right offset device (sheet alignment means)
76 Paper discharge roller moving motor 77 Paper discharge roller moving device 80 Left offset device (sheet alignment means)
95 Alignment position 96 Home position 97 Home position 98 Alignment position 100 Reader unit 200 Printer unit 201 Exposure control unit 202 Photosensitive member (image forming means)
300 Automatic document feeder ADF
400 Sheet stacking apparatus 501 Copying machine (image forming apparatus)
501A Device main body 510 CPU (control means)
520 Control unit of copying machine main body

Claims (5)

A sheet stacking means capable of moving up and down to stack sheets;
Sheet elevating means for elevating the sheet stacking means;
Sheet detecting means for detecting the sheets stacked on the sheet stacking means;
Control that controls the sheet lifting / lowering means based on the sheet detection operation of the sheet detection means so that the uppermost sheet among the sheets stacked on the sheet stacking means is positioned at a predetermined height position. Means,
Sheet pressing means for pressing the upper surface of the sheets stacked on the sheet stacking means;
A sheet stacking apparatus comprising:   A sheet aligning unit that aligns at least one side end along the sheet conveying direction of the sheet stacked on the sheet stacking unit, and the sheet aligning unit holds the sheet when the sheet pressing unit holds the sheet The sheet stacking apparatus according to claim 1, wherein the sheet stacking position is at a position where the sheets are aligned.   The sheet pressing unit has a function of conveying the sheet stacked on the sheet stacking unit to the upstream side in the sheet conveying direction, and an upstream end portion of the sheet conveyed to the upstream side by the sheet pressing unit. 3. The sheet stacking apparatus according to claim 1, further comprising stopper means for receiving the sheet. Image forming means for forming an image on a sheet;
A sheet stacking device on which the sheets on which images are formed by the image forming unit are stacked,
The image forming apparatus according to claim 1, wherein the sheet stacking apparatus is the sheet stacking apparatus according to claim 1. Image forming means for forming an image on a sheet;
A sheet stacking unit capable of moving up and down on which the sheet on which an image is formed by the image forming unit is stacked;
Sheet elevating means for elevating the sheet stacking means;
Sheet detecting means for detecting the sheets stacked on the sheet stacking means;
Control that controls the sheet lifting / lowering means based on the sheet detection operation of the sheet detection means so that the uppermost sheet among the sheets stacked on the sheet detection means is positioned at a predetermined height position. Means,
Sheet pressing means for pressing the upper surface of the sheets stacked on the sheet stacking means;
An image forming apparatus comprising:

Images