JP2012211022A - Sheet stacking device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow sheets to be stacked at a desired position in stacker trays by enabling a sheet discharge section to move.SOLUTION: An extension roller 122a is moved to a position where the extension roller is contacted with a discharge belt 154 corresponding to a stacker tray 112a of a plurality of stacker trays 112a, 112b or driving rollers 124 corresponding to a stacker tray 112b. The moved extension roller 122a, and the driving rollers 124 contacted with the extension roller 122a or the discharge belt 154 sandwich a sheet and discharge the sheet to one of the stacker trays 112a, 112b.

Description

  The present invention relates to a sheet stacking apparatus for stacking sheets and an image forming apparatus including the sheet stacking apparatus in an apparatus main body.

  Conventionally, as shown in FIG. 18, the image forming apparatus 2 includes an apparatus main body 2 </ b> A containing an image forming unit 10 that forms an image on a sheet, and a sheet stacking apparatus 1 provided in the apparatus main body. There is a thing (patent document 1). In recent years, an image forming apparatus has a high image forming speed, and a large number of sheets are stacked on the sheet stacking apparatus.

  The conventional sheet stacking apparatus 1 includes two stack units 3A and 3B that stack sheets and move up and down individually. The sheet stacking apparatus 1 can stack the conveyed sheet on the left first stack unit 3 </ b> A by the first paper discharge roller pair 15 when the switching guide claw 16 is rotated upward (the position indicated by the broken line). The first stack unit 3A descends as the sheets are stacked, and stops descending when the full load detection sensor 19 detects the full load of the sheets. Thereafter, the switching guide claw 16 rotates downward (solid line position). The conveyed sheet is guided to the second discharge roller pair 18 on the right side. The second paper discharge roller pair 18 stacks sheets on the second stack unit 3B. The second stack unit 3B also descends as the sheets are stacked, and stops descending when the full load detection sensor 20 detects the full sheet.

  The length of the sheet in the above-described sheet stacking is not more than half (L / 2) of the length (L) of the sheets stacked across the two stack portions 3A and 3B.

JP-A-9-255213

  By the way, in the conventional sheet stacking apparatus 1, the sheet discharge portion that is a portion for discharging the sheet is fixed at the position of the first discharge roller pair 15 and the second discharge roller pair 18. For this reason, the conventional sheet stacking apparatus 1 is stacked on the entire length of the first stack unit 3A and is stacked on substantially half of the second stack unit 3B such that the length of the sheet is (3/4) L. In the case of a half-length sheet, the sheet is discharged from the first discharge roller pair 15.

  For this reason, in the case of a half-length sheet, the conventional sheet stacking apparatus stacks mainly on the first stack unit A side with reference to the first discharge roller pair 15, for example, The user could not load the sheet at a desired position where the user wanted to take out the sheet.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet stacking apparatus that can move a sheet discharge section so that sheets can be stacked at a desired position, and an image forming apparatus including the sheet stacking apparatus.

  The sheet stacking apparatus according to the present invention includes: a sheet discharge unit that discharges a sheet; and a plurality of sheet stacking units that are arranged in parallel in a sheet discharge direction and on which the sheet discharged from the sheet discharge unit is stacked. The discharge means includes a plurality of discharge rotators arranged corresponding to the plurality of sheet stacking means, and a moving roller movable to a position in contact with any one of the plurality of discharge rotators. A discharge rotating body in which the moving roller is in contact with a discharge rotating body corresponding to one of the plurality of sheet stacking means, and the moving roller and the moving roller are in contact with each other The sheet is sandwiched and discharged to the one sheet stacking means.

  In the sheet stacking apparatus of the present invention, the moving roller is moved to a position in contact with the discharge rotator corresponding to the sheet stacking unit, and the sheet is sandwiched by the contacted discharge rotator and discharged to one sheet stacking unit. With a simple configuration, the sheet can be discharged to any one of a plurality of sheet stacking means.

FIG. 3 is a cross-sectional view of the image forming apparatus according to the embodiment of the present invention along the sheet conveyance direction. 2 is a control block diagram for controlling the entire image forming apparatus. FIG. 6 is a flowchart for explaining schematic operations of a stacker that is a sheet stacking apparatus according to a reference example of the invention. FIG. 10 is a state diagram when sheets are stacked on the right stacker tray in the stacker of the reference example of the present invention. FIG. 5 is a state diagram in the middle of stacking sheets on the right stacker tray from the state of FIG. 4. FIG. 6 is a state diagram in which sheets are stacked on the right stacker tray from the state of FIG. 5. FIG. 5 is a state diagram when sheets are stacked on the left stacker tray in the stacker of the reference example of the present invention. FIG. 8 is a state diagram in the middle of stacking sheets on the right stacker tray from the state of FIG. 7. FIG. 9 is a state diagram in which sheets are stacked on the right stacker tray from the state of FIG. 8. It is a schematic perspective view of an extension path. FIG. 5 is a state diagram when sheets are stacked on the entire length of the left stacker tray and in the middle of the right stacker tray. FIG. 6 is a state diagram when sheets are stacked on the middle of the left stacker tray and the entire length of the right stacker tray. It is the schematic of the stacker which is a sheet | seat stacking apparatus of embodiment of this invention using a short discharge belt. FIG. 10 is a diagram when the sheets stacked on the right stacker tray are carried out by a dolly. FIG. 10 is a diagram when the sheets stacked on the left stacker tray are carried out by a dolly. FIG. 10 is a diagram when the sheets stacked on both the left and right stacker trays are carried out by a dolly. 6 is a flowchart for explaining operations when stacking sheets on a stacker tray. FIG. 10 is a cross-sectional view of a stacker that is a conventional sheet stacking device along a sheet conveying direction.

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

(Image forming device)
FIG. 1 is a cross-sectional view of the image forming apparatus according to the embodiment of the present invention along the sheet conveyance direction. The image forming apparatus 900 includes an apparatus main body 900A for forming an image and a stacker 100 (or 300) as a sheet stacking apparatus for stacking sheets, and forms an image on a sheet. The stacker 100 (or 300) may be incorporated in the apparatus main body 900A. The apparatus main body 900A includes an automatic document feeder 950 that automatically supplies a document to the image reading device 951. The image reading device 951 reads a document automatically fed from the automatic document feeder 950. Note that the image reading device 951 and the automatic document feeder 950 are not necessarily required. When the image forming apparatus 900 does not include the image reading apparatus 951, the image forming apparatus 900 forms an image on a sheet based on sheet image information sent from an external facsimile or a personal computer.

  The operation of the apparatus main body 900A of the image forming apparatus will be described. The sheet S set in the sheet feeding cassettes 902a to 902e is conveyed to the registration roller pair 910 by the sheet feeding rollers 903a to 903e and the conveying roller pair 904. On the other hand, an electrostatic latent image is formed on the photosensitive drum 906 that is primarily charged by the primary charger 907 by an exposure unit 908 that exposes digital document data from the image reading device 951. The electrostatic latent image is developed with toner by the developing device 909 to become a toner image. The photosensitive drum 906, the primary charger 907, the developing unit 909, and the like constitute an image forming unit 916.

  The registration roller pair 910 feeds the sheet between the photosensitive drum 906 and the transfer separation charger 905 at the timing when the leading edge of the sheet and the leading edge of the toner image on the photosensitive drum 906 are aligned. The transfer separation charger 905 is applied with a transfer bias and transfers the toner image on the photosensitive drum 906 to a sheet. The sheet onto which the toner image has been transferred is conveyed to the fixing device 912 by the conveying belt 911 and is heated and pressed by the fixing device 912 to fix the toner image. At this time, residual toner and foreign matter remaining on the photosensitive drum 906 without being transferred to the sheet are scraped off by the blade of the cleaning device 913. The photosensitive drum 906 is cleaned to prepare for the next image formation. The sheet on which the toner image is fixed is conveyed as it is to the stacker 100 (or 300) by the paper discharge roller 914, or is conveyed to the duplex reversing device 901 by the switching member 915 for switching the sheet conveyance direction, and image formation is performed again. Done.

(Control block diagram)
FIG. 2 is a control block diagram for controlling the entire image forming apparatus 900.

  The CPU circuit unit 206 includes a ROM 207 and a RAM 208, and controls each of the blocks 202, 203, 204, 201, 205, 209, and 210 according to a control program stored in the ROM 207. The RAM 208 temporarily stores control data and is used as a work area for arithmetic processing associated with control.

  The DF control unit 202 controls driving of the automatic document feeder 950 based on an instruction from the CPU circuit unit 206. The image reader control unit 203 performs drive control on the image reading device 951, the image sensor, and the like, and transfers an analog image signal output from the image sensor to the image signal control unit 204.

  The image signal control unit 204 converts each analog image signal from the image sensor into a digital signal, performs each process, converts the digital signal into a video signal, and outputs the video signal to the printer control unit 205. In addition, the digital image signal input from the computer 200 via the external I / F 201 is subjected to various processes, and the digital image signal is converted into a video signal and output to the printer control unit 205. The processing operation by the image signal control unit 204 is controlled by the CPU circuit unit 206. The printer control unit 205 drives the exposure unit 908 based on the input video signal.

  The operation unit 209 includes a plurality of keys for setting various functions relating to image formation, a display unit for displaying information indicating a setting state, and the like. The operation unit 209 outputs a key signal corresponding to the operation of each key to the CPU circuit unit 206, and displays corresponding information on the display unit based on the signal from the CPU circuit unit 206. Here, a position where the user faces the operation unit 209 for performing various inputs / settings on the image forming apparatus 900 is referred to as a front front side (hereinafter referred to as a front side) of the image forming apparatus, and a rear side of the apparatus is referred to as a back side. FIG. 1 shows the configuration of the image forming apparatus viewed from the front side of the apparatus. The stacker 100 is connected to a side portion of the apparatus main body 900A.

  The stacker control unit 210 is mounted on the stackers 100 and 300, and performs drive control of the entire stacker by exchanging information with the CPU circuit unit 206. The stacker control unit 210 may be integrated into the CPU circuit unit 206 on the image forming apparatus main body 900A side, and the stackers 100 and 300 may be directly controlled from the image forming apparatus main body 900A.

(Basic stacking and stacking explanation of the stacker in the reference example)
Basic sheet conveyance control of the stacker 100 will be described based on the control block diagram of FIG. 2, the flowchart of FIG. 3, and the configuration diagrams of FIGS. 4 to 9. The sheet sent from the apparatus main body 900 </ b> A of the image forming apparatus 900 is conveyed into the stacker 100 by the entrance roller pair 101 of the stacker 100. Sheet information is sent to the stacker control unit 210 in advance from the CPU circuit unit 206 of the image forming apparatus 900 before the sheet is conveyed. The sheet information includes information such as sheet size, sheet type, and sheet discharge destination.

  When the sheet discharge destination is the top tray 106 (S301, S302), the stacker control unit 210 drives a solenoid (not shown) to switch the first switching member 103 from the solid line position to the broken line position (S303). In addition, the stacker control unit 210 drives a solenoid (not shown) to switch the second switching member 108 from the solid line position to the broken line position. The sheet is discharged to the top tray 106 by the guidance of the first switching member 103, the conveyance of the conveyance roller pair 107, the guidance of the second switching member 108, the conveyance of the conveyance roller pair 104, and the discharge of the top tray discharge roller pair 105. And loaded (S304).

  When the sheet discharge destination is the stacker trays 112a and 112b (S301 and S305), the stacker control unit 210 switches the first switching member 103 from the position of the broken line to the position of the solid line. The sheet is stacked on one of the stacker trays 112a and 112b by conveying the inlet roller pair 101, guiding the first switching member 103, and nipping and rotating the discharge belt 114 with the driven roller 110 and the extension rollers 122a and 122b. (S306). The discharge belt 114 is wound around a pair of pulleys 114a and 114b. One of the pulleys 114a and 114b is a driving pulley and the other is a driven pulley, and is disposed at a position protruding from the upstream side and the downstream side in the sheet discharging direction of the stacker tray 112a.

  When the sheet discharge destination is a sheet processing apparatus (not shown) connected to the downstream side of the stacker 100 (S301, S307), the stacker control unit 210 drives a solenoid (not shown) to move the first switching member 103 to a solid line. Switch from position to dashed line. Further, the stacker control unit 210 drives a solenoid (not shown) to switch the second switching member 108 from the broken line position to the solid line position (S308). The sheet is not conveyed due to the conveyance of the inlet roller pair 101, the guidance of the first switching member 103, the conveyance of the conveyance roller pair 107, the guidance of the second switching member 108, the conveyance of the conveyance roller pair 102, and the discharge of the outlet roller pair 109. It is sent to the illustrated sheet processing apparatus.

(Explanation of transporting and stacking basic small-size sheets in the stacker)
The basic small-size sheet conveyance control of the stacker 100 will be described with reference to the control block diagram of FIG. 2, the configuration diagrams of FIGS. 4 to 9, and the flowchart of FIG. The small size sheet is a sheet having a size stacked on one of the stacker trays 112a and 112b. In FIG. 17, the stacker tray 112a is abbreviated as tray a, and the stacker tray 112b is abbreviated as tray b.

  When the small size sheet is conveyed to the stacker 100, the stacker control unit 210 determines whether to stack the sheet on the stacker tray 112a (or the stacker tray 112b) selected by the operation unit 209 (S101). . The stacker control unit 210 determines whether or not sheets are stacked on the stacker tray 112a by the stack detection sensor 125a (FIG. 4) provided on the stacker tray 112a (S102). When there is no sheet or when a sheet having the same size as the already stacked sheets is stacked (No in S102, YES in S103), the stacker 100 starts stacking sheets (S104). When stacking a sheet having a size different from that of the already stacked sheets (NO in S103), the stacker control unit 210 confirms whether or not the stacker tray 112b can be stacked. When stacking sheets on the stacker tray 112a, the stacker 100 sequentially stacks sheets on the stacker tray 112a until it is full or the job is completed (other than that in S105). When the job is completed (job completion in S105), the stacker 100 pauses in a state where the sheet can be taken out (S106). The removal of the sheet will be described later. When full, the stacker 100 stacks sheets on another stacker tray, here, the stacker tray 112b (B in S101).

  When stacking small-sized sheets on the stacker tray 112b (B in S101), the stacker control unit 210 determines whether or not sheets are stacked on the stacker tray 112b by the stack detection sensor 125b provided on the stacker tray 112b. (S112). When there is no sheet or when a sheet having the same size as the already loaded sheet is stacked (No in S112, YES in S113), the stacker 100 moves the extension rollers 122a and 122b to extend an extension path 130 described later, Sheet stacking is started on the stacker tray 112b. When stacking a sheet having a size different from that of the already stacked sheets (NO in S113), the stacker control unit 210 confirms whether or not the stacker tray 112a can be stacked. When stacking sheets on the stacker tray 112b, the stacker 100 sequentially stacks sheets on the stacker tray 112b until full or until the job is completed (other than that in S115). When the job is completed (job completion in S115), the stacker control unit 210 contracts the extended extension path 130 and temporarily stops the stacker 100 so that the sheet can be taken out (S116). The removal of the sheet will be described later. When the stacker is full, the stacker control unit 210 controls the stacker 100 so that sheets are stacked on the stacker tray 112a which is another stacker tray.

(Explanation regarding stacker tray)
The stacker trays 112a and 112b for stacking the discharged sheets are disposed so as to be individually raised and lowered in directions of arrows C, D, E, and F in the drawing by a drive unit (not shown). The stacker trays 112a and 112b are detected by the home position detection sensors 113a and 113b, and stand by at the home position. The sheet retracting unit 115 is movably provided on the sliding shaft 118 and can be moved in the directions of arrows A and B by a driving unit (not shown).

  The sheet retracting unit 115 includes a knurled belt 116. The knurled belt 116 is rotated clockwise by a driving unit (not shown) so as to draw the sheet into the leading end stopper 121. The sheet drawing unit 115 is also provided with a paper surface detection sensor 117. The paper surface detection sensor 117 is provided to keep the distance between the knurled belt 116 and the upper surface of the sheet constant, so that the sheet can be stably drawn and stacked on the stacker tray 112a (112b).

(Description of operation when sheets are stacked on the right stacker tray 112a)
A case where sheets are stacked on the right stacker tray 112a will be described with reference to FIGS.

  Both empty stacker trays 112a and 112b are detected by the home position detection sensors 113a and 113b and are waiting at the home position in order to stack sheets. When the sheet information input to the operation unit 209 is sent from the CPU circuit unit 206, the stacker control unit 210 uses the sheet information in the sheet length information, the stacker tray designation information, and the like. Based on this, the position of the sheet retracting unit 115 is determined. When the sheet length information is the length information stacked on the right stacker tray 112a, or when the designation information is the right stacker tray, the stacker control unit 210 moves the sheet pull-in unit 115 of the stacker tray 112a. Move to the downstream end in the sheet discharge direction.

  Further, the stacker control unit 210 makes the extension roller 122a come into contact with the upstream end portion of the discharge belt 114 and stands by. Therefore, the position where the extension roller 122a is in contact with the upstream end portion of the discharge belt 114 becomes the sheet discharge portion, and the stacker 100 can stack the sheets on the stacker tray 112a desired by the user.

  As shown in FIG. 5, the sheet S sent out from the apparatus main body 900 </ b> A of the image forming apparatus 900 (FIG. 1) is conveyed to the discharge belt 114 by the conveyance of the inlet roller pair 101 and the guidance of the first switching member 103. Is done. The discharge belt 114 rotates with the driven roller 110 and the extension rollers 122a and 122b sandwiching the sheet, and conveys the sheet toward the sheet drawing unit 115 at the same sheet conveyance speed as the inlet roller pair 101.

  The stacker control unit 210 detects the sheet conveying speed of the discharge belt 114 from the time when the timing sensor 111 detects the passage of the leading edge of the sheet until just before the trailing edge of the sheet S passes between the discharge belt 114 and the extension roller 122a. To slow down. The sheet S is decelerated and sent to the knurled belt 116 in a stable state, and is reliably abutted against the leading end stopper 121 by the knurled belt 116 as shown in FIG. As a result, the sheets are stacked on the stacker tray 112a in a state where the skew is corrected and the alignment of the leading ends is enhanced.

  Thereafter, the pair of alignment plates 119a and 119c approach each other in a direction perpendicular to the sheet discharge direction to correct the deviation of the sheet in the perpendicular direction from both sides of the sheet. That is, the pair of alignment plates 119a and 119c performs sheet width alignment. In FIG. 6, the alignment plate denoted by reference numeral 119a is disposed on the front side, and the alignment plate denoted by reference numeral 119c is disposed on the back side. After discharging the sheet S, the discharge belt 114 waits so that the circulation speed is accelerated and the subsequent sheet can be conveyed at the same sheet conveyance speed as the inlet roller pair 101.

  The stacker 100 repeats the above operation, and sequentially stacks sheets S on the stacker tray 112a with good alignment. The paper surface detection sensor 117 constantly monitors the upper surface of the stacked sheets. The stacker control unit 210 controls the lowering of the stacker tray 112a when the paper surface detection sensor 117 detects the uppermost sheet, so that the interval between the knurled belt 116 of the sheet drawing unit 115 and the uppermost sheet is always constant. Hold at intervals. As a result, the pulling force of the sheet by the knurled belt 116 is kept constant, and the consistency of the leading edge of the sheet can be improved.

  The number of sheets stacked on the stacker tray 112a is detected by the stacker control unit 210 counting the number of sheets detected by the timing sensor 111. When the count number reaches the predetermined number, the stacker control unit 210 determines that the sheets on the stacker tray 112a are full. The full load may be determined by detecting a sheet (not shown) that detects that the stacker tray 112a on which the sheets are sequentially stacked has been lowered to a predetermined position.

  When the sheets on the stacker tray 112a become full, the stacker tray 112a automatically lowers further, and is fixed on a dolly 120 shown in FIG. The sheet carry-out by the dolly will be described later. The stacker tray 112a is supported by a fork-like claw (not shown) that can be raised and lowered, and the claw enters the gap between the pair of ridges 120a of the dolly 120. Placed on top.

(When stacking sheets on the left stacker tray 112b)
A case where sheets are stacked on the left stacker tray 112b will be described with reference to FIGS.

  When the sheet information input to the operation unit 209 is sent from the CPU circuit unit 206, the stacker control unit 210 uses the sheet information in the sheet length information, the stacker tray designation information, and the like. Based on this, the position of the sheet retracting unit 115 is determined. When the sheet length information is the length information stacked on the left stacker tray 112b, or when the designation information is the left stacker tray, the stacker control unit 210 causes the stacker tray 112a by a drive unit (not shown). 112b are lowered. The stacker control unit 210 lowers the stacker trays 112a and 112b to a position where the sheet pull-in unit 115 can move in the arrow A direction and stops the stacker trays 112a and 112b. Thereafter, the stacker control unit 210 moves the sheet pull-in unit 115 in the direction of arrow A by a driving unit (not shown) and stops it at the downstream end of the stacker tray 112b in the sheet discharge direction. Thereafter, the stacker tray 112b rises to a position detected by the home position detection sensor 113b.

  Thereafter, as shown in FIG. 7, the extension roller 122 a of the extension path 130 moves to the downstream end portion of the discharge belt 114, and the extension roller 122 b moves to the intermediate portion of the discharge belt 114. Here, the extension path 130 having the extension rollers 122a and 122b will be described with reference to FIG.

  A pair of guide shafts 131 are fixedly disposed along the sheet discharge direction. Each guide shaft 131 is provided with sliders 132 and 133 that are movable on the guide shaft 131. The slider 132 and the slider 132 are connected to each other by a roller support shaft 134. The slider 133 and the slider 133 are also connected to each other by a roller support shaft 135. The roller support shafts 134 and 135 are prevented from rotating with respect to the sliders 132 and 133. A plurality of extension rollers 122a are rotatably provided on the roller support shaft 134. A plurality of extension rollers 122b are rotatably provided on the roller support shaft 135.

  A film shaft 136 is fixedly disposed upstream of the roller support shaft 135 in the sheet discharge direction. The roller support shafts 134 and 135 and the film shaft 136 are parallel to each other. The film shaft 136 is provided with a take-up reel 137 for winding the reel film 123. The leading end of the reel film 123 is provided on a film drawing member 138 provided on the roller support shaft 134. Instead of the reel film 123, a contractible bellows-like member or a member that is formed by connecting a plurality of narrow strip-like plates and can be expanded and contracted may be used.

The slider 132 is connected to a belt 139 that circulates by a motor (not shown).
The slider 132 and the slider 133 are connected by a tension spring 140. The movement distance of the slider 133 is regulated by a fixed stopper 141 so that the slider 133 can move only about half of the movement distance of the slider 132. The stopper 141 is fixed at a position where it does not contact the moving slider 132.

  In the above-described configuration, when the belt 139 circulates in the arrow G direction, the extension path 130 moves together with the belt 139 in the arrow G direction. Then, the roller support shaft 134, the extension roller 122a, the film drawing member 138, and the slider 132 on the left side in FIG. At this time, the film drawing member 138 draws the reel film 123 from the take-up reel 137.

  When the slider 132 moves in the arrow G direction, the slider 133 is also moved in the arrow G direction by being pulled by the tension spring 140. When the slider 133 moves, the roller support shaft 135, the extension roller 122b, and the slider 133 on the left side in FIG.

  As shown in FIG. 7, when the extension roller 122a moves to the downstream end of the stacker tray 112a and the discharge belt 114 in the sheet discharge direction, the belt 139 stops circulation. During this time, the slider 133 abuts on the stopper 141 and is stopped at a substantially central position of the stacker tray 112a. The tension spring 140 extends to a length that does not cause plastic deformation. The extension rollers 122a and 122b are always in direct contact with the discharge belt 114 or indirectly through a sheet so as to follow and follow the driving circulation of the discharge belt 114.

  Further, the reel film 123 extends below the discharge belt 114 to a position where the extension roller 122a has moved. For this reason, the reel film 123 supports the sheet discharged to the stacker tray 112b, and the discharge belt 114 prevents the sheet from floating above the sheet.

  In FIG. 7, the extension roller 112 a has moved to the downstream end of the discharge belt 114, which means that the sheet discharge unit has moved to the downstream end of the discharge belt 114, and the sheet is placed on the stacker tray 112 b desired by the user. Can be loaded. Therefore, FIG. 7 is a diagram showing that the extension path 130 is extended to the upstream side of the stacker tray 112b, and preparation for stacking sheets on the stacker tray 112b is completed.

  When the belt 139 (FIG. 10) circulates in the arrow J direction, movable members such as the extension rollers 122a and 122b move in the arrow J direction. As shown in FIG. 4, the extension rollers 122 a and 122 b approach the downstream side of the driven roller 110 and stand by. In FIG. 4, the driven roller 110 and the extension rollers 122a and 122b appear to overlap each other because the driven roller 110 and the extension rollers 122a and 122b are disposed so as to be displaced from each other in the axial direction.

  As shown in FIG. 8, the sheet conveyed from the apparatus main body 900A of the image forming apparatus 900 to the discharge belt 114 is thereafter supported by the reel film 123 and is transferred to the stacker tray 112b by the discharge belt 114 and the extension rollers 122a and 122b. Be transported.

  The stacker control unit 210 decelerates the sheet conveyance speed of the discharge belt 114 and feeds it to the knurled belt 116 in a stable state, as in the case where the sheets are stacked on the stacker tray 112a, and reliably contacts the leading end stopper 121. . As a result, the skew of the sheet is corrected and the alignment of the leading edge is improved.

  Thereafter, the pair of alignment plates 119b and 119d perform sheet width alignment in the same manner as the pair of alignment plates 119a and 119c. In FIG. 9, the alignment plate indicated by reference numeral 119b is disposed on the front side, and the alignment plate indicated by reference numeral 119d is disposed on the rear side. After discharging the sheet S, the discharge belt 114 waits so that the circulation speed is accelerated and the subsequent sheet can be conveyed at the same sheet conveyance speed as the inlet roller pair 101.

  The stacker 100 repeats the above operation, and sequentially stacks sheets S on the stacker tray 112b with good alignment. The stacker controller 210 controls the lowering of the stacker tray 112b when the paper surface detection sensor 117 detects the uppermost sheet, so that the interval between the knurled belt 116 and the uppermost sheet of the sheet drawing unit 115 is always constant. Hold at intervals. As a result, the pulling force of the sheet by the knurled belt 116 is kept constant, and the consistency of the leading edge of the sheet can be improved.

  The sheets stacked on the stacker tray 112b are detected in the same manner as when stacked on the stacker tray 112a, and are placed and fixed on the pair of protrusions 120b and 120b of the dolly 120.

(Description of operation when stacking sheets across the right and left stacker trays 112a and 112b)
In this case, the extension rollers 122a and 122b stand by at the upstream end of the discharge belt 114, and the sheet drawing unit 115 waits at the downstream end of the left stacker tray 112b and stacks sheets on the right stacker tray 112a. It is performed by the same operation as the case.

(When loading on the left stacker tray and loading halfway to the right stacker tray)
As shown in FIG. 11, a description will be given of a case where sheets S1 are stacked on the left stacker tray 112b and are stacked halfway on the right stacker tray 112a.

  When the sheet information input to the operation unit 209 is sent from the CPU circuit unit 206, the stacker control unit 210 uses the sheet information in the sheet length information, the stacker tray designation information, and the like. Based on this, the position of the sheet retracting unit 115 is determined.

  When the sheet information is information for stacking the sheet S1 on the left stacker tray 112b and loading the sheet S1 in the middle of the right stacker tray 112a, the stacker control unit 210 moves the sheet retracting unit 115 to the downstream end of the stacker tray 112b. Let the side wait. Then, the extension roller 122a is put on standby at a position corresponding to the length of the sheet. The extension roller 122a stands by on the middle of the right stacker tray 112a. In this case, an intermediate position of the discharge belt 114 where the extension roller 122a is in contact with the discharge belt 114 becomes a sheet discharge portion, and the sheets are stacked on the full length of the stacker tray 112b desired by the user and halfway on the stacker tray 112a. be able to.

  Furthermore, the stacker control unit 210 causes the home position detection sensors 113a and 113b to detect the stacker trays 112a and 112b and waits at the home position.

  As shown in FIG. 11, the sheet S <b> 1 sent out from the apparatus main body 900 </ b> A of the image forming apparatus 900 (FIG. 1) is conveyed to the discharge belt 114 by the conveyance of the inlet roller pair 101 and the guidance of the first switching member 103. Is done. The discharge belt 114 rotates while sandwiching the sheet between the driven roller 110 and the extension rollers 122a and 122b, and is conveyed toward the sheet drawing unit 115 at the same sheet conveyance speed as that of the inlet roller pair 101.

  The stacker control unit 210 decelerates the sheet conveyance speed of the discharge belt 114 and feeds it to the knurled belt 116 in a stable state, as in the case where the sheets are stacked on the stacker tray 112a, and reliably contacts the leading end stopper 121. . As a result, the skew of the sheet is corrected and the alignment of the leading edge is improved.

  Thereafter, the pair of alignment plates 119a, 119c and 119b, 119d performs sheet width alignment. After the sheet S1 is discharged, the discharge belt 114 waits so that the circulation speed is accelerated and the subsequent sheet can be conveyed at the same sheet conveyance speed as the inlet roller pair 101.

  The stacker 100 repeats the above operation to sequentially stack the sheets S1 on the stacker trays 112a and 112b with good alignment. The paper surface detection sensor 117 constantly monitors the upper surface of the stacked sheets. The stacker control unit 210 controls the lowering of the stacker trays 112a and 112b when the paper surface detection sensor 117 detects the uppermost sheet, so that the interval between the knurled belt 116 of the sheet retracting unit 115 and the uppermost sheet is always maintained. Hold at regular intervals. As a result, the pulling force of the sheet by the knurled belt 116 is kept constant, and the consistency of the leading edge of the sheet can be improved.

  When the sheets on the stacker trays 112a and 112b become full, the sheets are stacked on the dolly 120 and carried out.

(When loading on the right stacker tray and halfway to the left stacker tray)
As shown in FIG. 12, a case will be described in which sheets S1 are stacked on the right stacker tray 112a and stacked halfway on the left stacker tray 112b.

  In the case where the sheet information is information that stacks the sheet S1 on the right stacker tray 112a and stacks halfway on the left stacker tray 112b, the stacker control unit 210 sets the sheet retracting unit 115 to correspond to the length of the sheet. Wait in the middle of the stacker tray 112b. Then, the extension roller 122a is put on standby at the upstream end of the discharge belt 114. In this case, the position of the upstream end portion of the discharge belt 114 where the extension roller 122a is in contact with the discharge belt 114 becomes the sheet discharge portion, and the sheet reaches the full length of the stacker tray 112a desired by the user and the middle of the stacker tray 112b. Can be loaded.

  Further, the stacker control unit 210 causes the home position detection sensors 113a and 113b to detect the stacker tray 112b and waits at the home position.

In FIG. 12, the sheet S1 fed from the apparatus main body 900A of the image forming apparatus 900 (FIG. 1) is rotated by the discharge belt 114 with the driven roller 110 and the extension rollers 122a and 122b sandwiching the sheet. It is discharged to 112a and 112b.
During this time, the sheet conveying speed of the discharge belt 114 is controlled as in the case of FIG. The sheet S1 is fed into the knurled belt 116 in a stable state, and is reliably abutted against the leading end stopper 121 by the knurled belt 116. As a result, even if the leading end of the sheet is positioned in the middle of the stacker tray 112b, skewing is corrected and the leading end alignment is improved.

  Thereafter, the pair of alignment plates 119a, 119c and 119b, 119d performs sheet width alignment.

  The stacker 100 repeats the above operation to sequentially stack the sheets S1 on the stacker trays 112a and 112b with good alignment. When the sheets on the stacker trays 112a and 112b become full, the sheets are stacked on the dolly 120 and carried out.

(Stacker in the embodiment)
In the stacker 100 of the reference example, the extension path 130 discharges the sheet by driving circulation of the discharge belt 114, but the drive roller 124 is disposed downstream of the discharge belt 154 as in the extension path 150 of FIG. 13. May be provided. The length of the discharge belt 154 of the stacker 300 in the embodiment of the present invention shown in FIG. 13 is shorter than the length of the discharge belt 114 shown in FIGS. Further, the driving roller 124 is disposed near the upstream side of the stacker tray 112b so that the extension roller 122a comes into contact therewith. In this case, a position where the driving roller 124 and the extension roller 122a are in contact with each other becomes a sheet discharge portion to the stacker tray 112b. Although the characteristic part of the structure in the stacker of embodiment is demonstrated below, description is abbreviate | omitted about the structure which is common in the stacker of a reference example.

  4, 7, and 11, the discharge belt 114 improves the stackability of sheets. After the timing sensor 111 detects the sheet, the trailing end of the sheet S is the discharge belt 114 and the extension roller 122 a. It is designed to decelerate until just before getting through. However, when the subsequent belt is fed to the discharge belt while the discharge belt 114 is decelerated or returned to the original speed, the subsequent sheet is conveyed faster than the discharge belt by the inlet roller pair 101. Since it is transported at a high speed, there is a risk of loosening and clogging. For this reason, the succeeding sheet cannot be fed into the discharge belt during the deceleration circulation or the acceleration circulation. Therefore, it is necessary to leave a gap between the sheet being discharged and the subsequent sheet by the length of the discharge belt.

  On the other hand, the discharge belt 154 in the extension path 150 in FIG. 13 constantly circulates at the same sheet conveyance speed as the inlet roller pair 101. Instead, the drive roller 124 rotates at a reduced speed and at an accelerated speed.

  When the sheet is fed, the driving roller 124 receives the sheet from the discharge belt 154. At this time, the driving roller 124 conveys the sheet at the same sheet conveyance speed as the entrance roller pair 101. The drive roller 124 rotates at a reduced speed when the trailing edge of the sheet passes the discharge belt 154. The sheet comes into contact with the leading end stopper 121 of the sheet drawing unit 115, is aligned at the leading end, and is stacked on the stacker tray 112b. The driving roller 124 returns to the original sheet conveying speed when the trailing edge of the sheet passes.

  As described above, the extension path 150 shown in FIG. 13 is configured to decelerate and convey the sheet by the driving roller 124, so that the interval between the preceding sheet and the succeeding sheet is set at the downstream end of the discharge belt 154 and the driving roller 124. The interval can be shortened.

  Therefore, the stacker shown in FIG. 13 can reduce the influence on the sheet conveyance speed and can stack the sheets on the stacker tray 112b.

  In the stacker shown in FIG. 13 as well, the extension roller 122a may be brought into contact with the discharge belt 154 so that the position of the extension roller 122a can be changed, so that the sheet discharge portion can be changed to a desired position in accordance with the discharge to the stacker tray 112a. . That is, the extension roller 122a may be brought into contact with a desired position of the discharge belt 154 so that the position of the sheet discharge portion can be changed. In this case, in order to enhance the sheet discharge consistency, it is preferable to rotate the discharge belt 154 at a reduced speed when discharging the sheet.

  The stacker 300 includes one drive roller 124 and one discharge belt 154, but the number is not limited. Further, a plurality of discharge belts may be provided without providing a driving roller. Even in this case, the sheet discharge unit can be changed to a desired position in accordance with the discharge to the stacker tray by bringing the extension roller 122a into contact with the selected discharge belt among the plurality of discharge belts so that the position can be changed. it can. Further, a plurality of drive rollers may be provided without providing a discharge belt. Even in this case, the sheet discharge unit can be changed to a desired position in accordance with the discharge to the stacker tray by bringing the extension roller 122a into contact with the selected drive roller among the plurality of drive rollers so that the position of the extension roller 122a can be changed. . These discharge belts and drive rollers are disposed not only above one stacker tray 112a but also above the other stacker tray 112b, and the extension rollers 122a and 122b are placed above the other stacker tray 112b. May also be movable.

(Unloading sheets from the stacker)
In the reference example and the embodiment described above, when the stacker trays 112a and 112b are lowered to the carry-out position by the control of the stacker control unit 210, the stacker trays 112a and 112b are fixed to the dolly 120 by fixing parts such as pins and recesses arranged on the dolly 120. The FIG. 14 shows a state where the stacker tray 112a is full of sheets. FIG. 15 shows a state in which the stacker tray 112b is full of sheets. FIG. 16 shows a state where the stacker tray 112a and the stacker tray 112b are full of sheets. In FIGS. 14 and 15, empty stacker trays do not necessarily have to be stacked.

  The dolly 120 is provided with four casters 126. When the user moves the dolly 120 with the handle 127, a large-capacity sheet bundle can be easily moved at once.

  Note that the sheet is not necessarily carried out by the dolly 120. The user may carry it out directly. In this case, the stacker according to the reference example and the embodiment of the present invention can change the position of the sheet discharge unit and stack sheets at a desired position on the stacker tray. It can be easily carried out without breaking.

  In the reference example and the embodiment described above, the home position detection sensors 113a and 113b are used to determine the initial lift position (home position) of the stacker tray. The initial position (home position) of the stacker trays 112a and 112b may be determined by using the paper surface detection sensor 117 instead of the home position detection sensor.

  In the above description, the sheet stacking order is the order of the right stacker tray 112a and the left stacker tray 112b, but the stacking order is not limited. The lengths of the two stacker trays may be different. Further, three or more stacker trays may be provided (a plurality of stacker trays may be provided in the sheet discharge direction).

  The discharge belts 114 and 154 and the driving roller 124 are on the driving side, and the extension rollers 122a and 122b are on the driven side. However, the discharging belts 114 and 154 and the driving roller 124 are on the driven side, and the extension rollers 122a and 122b are on the driving side. It may be.

  Further, the discharge belt 114 circulates at a reduced speed to reduce the impact when the sheet hits the leading edge stopper 121 and enhances the alignment of the leading edge of the sheet. However, depending on the sheet conveying speed of the inlet roller pair 101, the discharging belt 114 is decelerated. There is no need to circulate.

  As described above, the stacker 100 that is the sheet stacking apparatus of the reference example mainly includes the following components. That is, a discharge belt 114 as a sheet discharge means for discharging a sheet and extension rollers 122a and 122b as moving rotary members. Stacker trays 112a and 112b as sheet stacking means on which sheets discharged from the discharge belt 114 and the extension rollers 122a and 122b are stacked.

  In the stacker 100 having such a configuration, a sheet discharge portion is formed by the discharge belt 114 and the extension roller 122a that contacts the discharge belt, and the position of the extension roller 122a can be changed along the discharge belt. For this reason, the stacker 100 can change the position of the extension roller 122a according to the length of the sheet to change the sheet discharge portion to a desired position, and the stacker tray 112a, Sheets can be stacked at desired positions on 112b.

  Furthermore, as described above, the stacker 300 that is the sheet stacking apparatus of the present invention mainly includes the following components. That is, a discharge belt 154, a driving roller 124, and extension rollers 122a and 122b as sheet discharge means for discharging a sheet. As a sheet stacking means on which sheets discharged from a plurality of discharge belts 154 and drive rollers 124 as discharge rotating bodies and extension rollers 122a and 122b as moving rotating bodies are stacked along the sheet discharge direction. Stacker trays 112a and 112b.

  In the stacker 300 having such a configuration, a sheet discharge portion is formed by the discharge belt 154 and the drive roller 124 and the extension roller 122 a that contacts either the discharge belt 154 or the drive roller 124. In addition, the position of the sheet discharge portion can be changed by the extension roller 122a contacting either the discharge belt 154 or the drive roller 124. Therefore, the stacker 300 can change the position of the extension roller 122a in accordance with the length of the sheet to change the sheet discharge portion to a desired position, and the user can easily take out the sheet. Sheets can be stacked at desired positions on 112b. Further, the stacker 300 can stack the sheets on the stacker tray 112b with good consistency by rotating the driving roller 124 at a reduced speed.

  Furthermore, the sheet stacking surface and the positions of the extension rollers 122a (sheet discharge unit) can be discharged and stacked while maintaining a predetermined interval. For this reason, the stackers 100 and 300 can stably stack a large number of sheets on the stacker trays 112a and 112b at a high speed. Furthermore, since a large number of sheets are stacked with high accuracy, the sheets can be reliably conveyed to a predetermined position by the dolly 120 without disturbing the stacking accuracy.

  In addition, the stackers 100 and 300 include a reel film 123 as a belt-like body that can be pulled out and pulled back upstream of the extension rollers 122a and 122b in the sheet discharge direction as the extension rollers 122a and 122b move. The reel film 123 supports the sheet below the discharge belt when it is pulled out. For this reason, the stackers 100 and 300 can be discharged onto the stacker trays 112a and 112b without causing the sheets to be loosened and clogged between the extension rollers 122a and 122b.

  Further, the stacker includes a tip stopper 121 as a stopper. The front end stopper is provided downstream of the discharge belt in the sheet discharge direction, is movable in the sheet discharge direction, and is the front end of the sheet discharged from the discharge belt, the extension roller 122a, the driving roller 124, and the extension roller 122a. It has come to accept. For this reason, even if the position of the sheet discharge portion changes, the stackers 100 and 300 set the position of the leading end stopper 121 according to the length of the sheet discharge portion and the sheet, and the sheets are placed on the stacker trays 112a and 112b. It can be loaded with good consistency.

S sheet S1 sheet 100 stacker (sheet stacking apparatus of reference example of the present invention)
112a, 112b Stacker tray (sheet stacking means)
114 Discharge belt (sheet discharge means)
115 Sheet retracting units 119a, 119b, 119c, 119d Alignment plate 120 Dolly 121 Tip stopper (stopper)
122a, 122b Extension rollers (sheet discharge means, moving rotating body)
123 Reel film (band)
124 Drive roller (sheet discharge means, discharge rotating body)
150 Extension path 154 Discharge belt (sheet discharge means, discharge rotating body)
200 Computer 209 Operation unit 210 Stacker control unit 300 Stacker (sheet stacking apparatus according to the embodiment of the present invention)
900 image forming apparatus 900A apparatus main body 916 image forming unit 950 automatic document feeder 951 image reading apparatus

Claims (7)

Sheet discharge means for discharging the sheet;
A plurality of sheet stacking means that are arranged in parallel in the sheet discharge direction and on which the sheets discharged from the sheet discharge means are stacked,
The sheet discharging means is
A plurality of discharge rotators arranged corresponding to the plurality of sheet stacking means; and a movable roller movable to a position in contact with any one of the plurality of discharge rotators. The moving roller moves to a position where the moving roller contacts a discharge rotating body corresponding to one of the plurality of sheet stacking means, and the moving roller and the discharging rotary body in contact with the moving roller Sandwiching and discharging to the one sheet stacking means,
A sheet stacking apparatus characterized by that. At least one of the plurality of discharge rotators is a discharge belt, and the moving roller is movable along the discharge belt.
The sheet stacking apparatus according to claim 1, wherein: With the movement of the moving roller, a belt-like body that can be pulled out and pulled back is provided upstream in the sheet discharge direction of the moving roller, and when the belt-like body is drawn out, the discharging roller is in contact with the moving roller and the moving roller. Support the sheet discharged by the body,
The sheet stacking apparatus according to claim 1, wherein the sheet stacking apparatus is a sheet stacking apparatus. Provided downstream of the sheet discharge direction of the sheet discharge means, provided with a stopper that is movable in the sheet discharge direction and receives the leading edge of the sheet discharged from the sheet discharge means,
The sheet stacking apparatus according to claim 1, wherein the sheet stacking apparatus is a sheet stacking apparatus. The plurality of discharge rotators are independently driven,
Out of the plurality of sheet stacking units, the sheet is discharged to the sheet stacking unit downstream of the sheet discharge direction with the moving roller and a discharge rotating body disposed corresponding to the sheet stacking unit downstream of the sheet discharge direction. At the time, the moving roller and the discharge rotating body decelerate from the sheet conveying speed when the sheet is received,
The sheet stacking apparatus according to claim 1, wherein the sheet stacking apparatus is a sheet stacking apparatus. The moving roller is a driven roller;
The sheet stacking apparatus according to claim 5, wherein: An image forming unit for forming an image on a sheet;
The sheet stacking apparatus according to any one of claims 1 to 6, wherein sheets on which images are formed by the image forming unit are stacked.
An image forming apparatus.

Images