JP5644555B2 - Sheet stacking device - Google Patents

Description

  The present invention is arranged on the paper discharge side of an image forming apparatus such as a copying machine, a printer, or a multifunction machine, or on the paper discharge side of a paper post-processing device that performs post-processing of sheets (paper) such as stapling, punching, and paper folding. The present invention relates to a possible sheet stacking apparatus.

  2. Description of the Related Art Conventionally, for example, a sheet stacking apparatus that receives a sheet discharged from the image forming apparatus such as a copying machine and stacks a relatively large number of sheets on a liftable discharge tray is known. .

  In the conventional image forming apparatus, the speed of image formation is increased, and the sheet discharged from the main body of the image forming apparatus is also speeded up with the increase in speed. As a result, in a sheet stacking apparatus that stacks discharged sheets in a uniform manner, it is desired to align sheets not only with a large capacity but also with high speed and high accuracy.

  Therefore, the sheet stacking apparatus described in Patent Document 1 adopts a configuration in which the tray can be separated into two for the purpose of stacking sheets without breaking the bundle of sheets and without generating dirt and scratches due to rubbing. It was. As a result of this configuration, when the sheet size is small, a technique for aligning large capacity sheets by stacking sheets on each tray is disclosed.

  In addition, the sheet stacking device described in Patent Document 1 discloses a configuration in which alignment in the width direction of a sheet is performed by an alignment plate in a state where the sheet leading end portions are aligned.

JP 2008-179478 A

  However, in the conventional sheet stacking apparatus, as described above, in the front-rear direction of the sheet conveyance direction, the sheets are aligned only at the leading edge of the sheet, and the alignment accuracy in the front-rear direction of the sheet conveyance direction is compared with the left-right direction. There was a risk of lowering.

  Further, when a sheet is conveyed to two trays, the conveyance method is different for each tray, and it is necessary to switch the conveyance method, which causes a problem that productivity is lowered.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a sheet stacking apparatus capable of suppressing a reduction in sheet alignment accuracy and productivity in the front-rear direction of the sheet conveyance direction.

In order to solve the above-described problems and achieve the object, the present invention provides a sheet aligning unit that receives a sheet to be processed and aligns the sheet by bringing a movable fence into contact with an end of the sheet by a driving mechanism. A first tray capable of stacking the sheets, and a continuous tray along the sheet conveyance direction with respect to the first tray, as a separate tray from the first tray, Alternatively, in the second tray on which the sheets can be stacked as one tray integrally with the first tray, and in the first tray or the second tray, front and rear ends in the front-rear direction with respect to the sheet conveyance direction A longitudinal drive mechanism for driving and abutting the directional movable fence, a first conveyance path for conveying the sheet to the first tray, and conveying the sheet to the second tray A second conveyance path because, and a transport path switching means for selectively switching the first conveyance path or the second transport path, one of the first tray and the second tray, conveying of the sheet Sheets are supplied from the upstream side to the trays arranged on the upstream side in the direction by the corresponding conveyance path, and sheets are supplied from the downstream side to the trays arranged on the downstream side through the corresponding conveyance path. A sheet post-processing apparatus can be connected to the subsequent stage of the stacking apparatus, and a conveyance path provided on the downstream side of the pair of trays constitutes a sheet conveyance path to the sheet post-processing apparatus, and It is characterized in that it functions as a stacking direction changing means for allowing the sheets to be stacked in the same direction as the sheets supplied to the tray disposed on the upstream side .

  According to the present invention, the sheet alignment accuracy in the front-rear direction of the sheet conveyance direction can be ensured, and the first conveyance path and the second conveyance path are only selectively switched, so the conveyance method is the same for each tray. Thus, a decrease in productivity can be suppressed.

FIG. 1 is a block diagram illustrating a system configuration of the paper stacking apparatus according to the embodiment. FIG. 2 is an explanatory diagram of a schematic configuration of the stacker. FIG. 3 is a schematic configuration diagram of a shift transport mechanism that shifts the stacking position of sheets. FIG. 4 is an explanatory diagram showing the configuration of the tip alignment portion. FIG. 5 is an explanatory diagram showing the configuration of the main jogger of the stacker in FIG. 6 is a perspective view showing the configuration of the main jogger of the stacker in FIG. FIG. 7 is an explanatory diagram showing the configuration of the alignment section of the main jogger. FIG. 8 is an explanatory diagram of the configuration of the sub jogger mechanism.

  Exemplary embodiments of a sheet stacking apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the system configuration of the paper stacking apparatus according to this embodiment. In FIG. 1, a sheet stacking apparatus (hereinafter referred to as a stacker) 100 according to this embodiment is mechanically and electrically connected to a paper discharge side of an image forming apparatus 500 such as a copying machine, a printer, or a multifunction peripheral. It is constructed as an image forming processing system.
FIG. 2 is an explanatory diagram of a schematic configuration of the stacker.

First, the configuration of the stacker 100 will be described.
The stacker 100 includes a main control unit 10 that controls the entire stacker 100, a branch claw switching unit 20 that switches a sheet (paper) conveyance path, a proof discharge mechanism 23, a straight discharge mechanism 26, and a shift discharge. Mechanism 30.

  The main control unit 10 is configured as a microcomputer system including a CPU, a ROM, a RAM, a timer, and the like (not shown). The main control unit 10 controls each part of the stacker 100 based on a predetermined operation mode according to a control signal from the system controller 501 of the image forming apparatus 500, that is, a proof discharge mode, a straight discharge mode, and a shift discharge mode. Control. These operation modes will be described later in detail.

  The main control unit 10 executes drive control according to a program stored in the ROM for the drive system constituting the stacker 100.

  The branch claw switching unit 20 drives the branch claws N <b> 1 to N <b> 3 (see FIG. 2) to switch the sheet conveyance path that actually conveys the sheet, and the drive unit 21 under the control of the main control unit 10. And a drive control unit 22 that performs control.

  The proof paper discharge mechanism 23 controls the drive unit 24 under the control of the main control unit 10 and the drive unit 24 that drives each part of the proof paper discharge mechanism 23 when the operation mode is the proof paper discharge mode. Drive control unit 25.

  The straight paper discharge mechanism 26 drives the respective units constituting the straight paper discharge mechanism 26 when the operation mode is the straight paper discharge mode, and the drive that controls the drive unit 27 under the control of the main control unit 10. And a control unit 28.

  The shift paper discharge mechanism 30 controls the drive unit 41 under the control of the front end aligning unit 70 for aligning the front end of the sheet, the drive unit 41 that drives each part of the front end aligning unit 70, and the main control unit 10. A main jogger mechanism unit 200 that aligns a direction (sheet width direction; left-right direction of the sheet) that is orthogonal to the drive control unit 42 and the sheet conveyance direction of the sheet bundle constituted by the stacked sheets, and the main jogger mechanism unit 200, a drive unit 221 that drives each unit constituting the unit 200, a drive control unit 222 that controls the drive unit 221 under the control of the main control unit 10, and a sheet conveyance direction (sheets) of a sheet bundle composed of stacked sheets The sub-jogger mechanism unit 300 that aligns the front and rear directions), the drive unit 321 that drives each part of the sub-jogger mechanism unit 300, and the drive under the control of the main control unit 10. The sheet is discharged to a position shifted in a direction orthogonal to the sheet conveyance direction (sheet width direction; sub-scanning direction), and the shift direction is changed for each sheet bundle. A shift mechanism unit 350 that sorts the components, a drive unit 351 that drives each unit of the shift mechanism unit 350, a drive control unit 352 that controls the drive unit 351 under the control of the main control unit 10, and a stacker for stacking sheets. A tray mechanism unit 400, a drive unit 401 that drives each part of the tray mechanism unit 400, and a drive control unit 402 that controls the drive unit 401 under the control of the main control unit 10 are provided.

Next, the configuration of the image forming apparatus will be described.
The image forming apparatus 500 includes a system controller 501 that controls the overall control of the image forming apparatus 500 and exchange of control signals with peripheral devices, an operation display unit 502 that displays various input settings by the user, the state of the apparatus, and the like. And an image forming engine 503 that finally forms an image on a sheet according to image data using an image process.

Next, the operation of the embodiment will be described.
The stacker 100 introduces a sheet discharged from an image forming apparatus (not shown) from the direction of arrow A.
As an operation mode of the stacker 100, any one of three operation modes of a proof discharge mode, a straight discharge mode, and a shift discharge mode can be selected.

  The proof discharge mode is an operation mode in which a sheet is guided and stacked on the proof tray 101 via the first sheet conveyance path L1.

  The straight sheet discharge mode is an operation mode in which a sheet is guided to another sheet post-processing apparatus (for example, a stapler or a stacker) provided in the subsequent stage via the second sheet conveyance path L2 and the fourth sheet conveyance path L4. .

The shift discharge mode is an operation mode in which sheets are discharged and stacked on the first shift tray 102A via the third sheet conveyance path L3, and via the second sheet conveyance path L2 and the fifth sheet conveyance path L5. And an operation mode for discharging and stacking sheets on the second shift tray 102B. In this shift paper discharge mode, the drive control unit 352 controls the drive unit 351 under the control of the main control unit 10.
As a result, the drive unit 351 drives the shift mechanism unit 350 to discharge the sheet to a position shifted in a direction (sheet width direction; sub-scanning direction) orthogonal to the sheet conveyance direction. Thus, the sheets are stacked at different shift positions on the first shift tray 102A or the second shift tray 102B.

  The first shift tray 102A is placed on a first elevator 103A that can be raised and lowered. The four corners of the first elevator 103 </ b> A constituting the tray mechanism unit 400 are suspended by a total of four timing belts 104 </ b> A constituting the drive unit 401, and each of the timing belts 104 </ b> A corresponds to the drive unit 401. The timing pulley 105 is wound around.

  Each timing pulley 105 is linked by a gear train 107A composed of a plurality of gears as a drive unit 401 and a worm gear 106A, and is rotated synchronously by a driving force of a tray lifting / lowering motor 109A as a drive unit 401. Thus, the first elevator 103A is moved up and down together with the first shift tray 102A. Here, since the power transmission system is via the worm gear 106A, the first shift tray 102A can be kept at a fixed position. That is, even when power is not transmitted, the first shift tray 102A is not lowered by its own weight and is held at a fixed position.

When the first elevator 103A is lowered to the lowest position, by placing the first shift tray 102A on the carriage 108, the sheets stacked on the first shift tray 102A are put together with the first shift tray 102A. The cart 108 can be carried out. The first shift tray 102A is accommodated in the housing of the stacker 100 and cannot be touched unless an unillustrated opening / closing door provided in the housing is opened.
The paddle 110A rotates in the counterclockwise direction in the viewpoint of FIG. 2 and in the clockwise direction in the viewpoint of FIG. 3 in conjunction with the paper discharge roller 111A in the third sheet conveyance path L3, and is on the first shift tray 102A. Strike the vicinity of the rear edge of the discharged sheet and press it down. The sheets stacked on the first shift tray 102A push up the filler 112A. In the optical paper surface sensor S3A, the position of the uppermost surface of the sheets stacked on the first shift tray 102A is greater than or equal to a predetermined height from the predetermined reference position of the paper surface sensor S3A based on the movement of the filler 112A. Detect whether or not.

  When the paper surface sensor S3A is in an on state, that is, when the position of the top surface of the sheets stacked on the first shift tray 102A is equal to or higher than a predetermined height from a predetermined reference position, The first shift tray 102A is lowered by the tray lifting / lowering motor 109A. As a result of lowering of the first shift tray 102A, when the paper surface sensor S3A is turned off, the first tray lifting / lowering motor 109A is stopped.

  Therefore, each time the paper surface sensor S3A is turned on by the sheets stacked on the first shift tray 102A, the first shift tray 102A is lowered by a predetermined height.

  Further, the stacker 100 is provided at a sheet carry-in entrance, a paper feed path sensor (hereinafter referred to as an entrance sensor) S1 for detecting the passage of the sheet, and a paper feed path sensor for detecting the passage of the sheet in the third sheet transport path L3. (Hereinafter, a paper discharge sensor) S2A is provided. Further, a driven roller 113A biased by a spring is pressed against the paper discharge roller 111A, and a sheet is sandwiched and conveyed between these rollers 111A and 113A.

  The second shift tray 102B is placed on a second elevator 103B that can be raised and lowered. The four corners of the second elevator 103B are suspended by a total of four timing belts 104B, and each of the timing belts 104B is wound around a corresponding timing pulley 105.

  Each timing pulley 105 is linked by a gear train 107B composed of a plurality of gears and a worm gear 106B, and is rotated together with the second shift tray 102B by being rotated synchronously by the driving force of the tray lifting / lowering motor 109B. 2 Raise and lower the elevator 103B. Here, since the power transmission system is via the worm gear 106B, the second shift tray 102B can be kept at a fixed position. That is, even when power is not transmitted, the second shift tray 102B is not lowered by its own weight and is held at a fixed position.

  When the second elevator 103B is lowered to the lowest position, the second shift tray 102B is placed on the carriage 108 and loaded on the second shift tray 102B in the same manner as the first shift tray 102A. The sheet can be carried out by the carriage 108 together with the first shift tray 102B. The first shift tray 102A is accommodated in the housing of the stacker 100 and cannot be touched unless an unillustrated opening / closing door provided in the housing is opened.

  The paddle 110B rotates in the counterclockwise direction from the viewpoint of FIG. 2 and in the clockwise direction from the viewpoint of FIG. 2 in conjunction with the paper discharge roller 111B in the fifth sheet conveyance path L5, and is on the second shift tray 102B. Strike the vicinity of the rear edge of the discharged sheet and press it down. The sheets stacked on the second shift tray 102B push up the filler 112B. In the optical paper surface sensor S3B, the position of the uppermost surface of the sheets stacked on the second shift tray 102B is greater than or equal to a predetermined height from the predetermined reference position of the paper surface sensor S3B based on the movement of the filler 112B. Detect whether or not.

  When the paper surface sensor S3B is in an on state, that is, when the position of the top surface of the sheets stacked on the second shift tray 102B is equal to or higher than a predetermined height from a predetermined reference position, The second shift tray 102B is lowered by the tray lifting / lowering motor 109B. As a result of the lowering of the second shift tray 102B, when the paper surface sensor S3B is turned off, the second tray lifting / lowering motor 109B is stopped.

  Accordingly, every time the paper surface sensor S3B is turned on by the sheets stacked on the second shift tray 102B, the second shift tray 102B is also lowered by a predetermined height in the same manner as the first shift tray 102A.

  Further, the stacker 100 includes a sheet conveyance path sensor (hereinafter referred to as a sheet discharge sensor) S2B for detecting the passage of the sheet in the fifth sheet conveyance path L5. Further, a driven roller 113B biased by a spring is pressed against the paper discharge roller 111B, and a sheet is sandwiched and conveyed between these rollers 111B and 113B.

FIG. 3 is a schematic configuration diagram of a shift paper discharge mechanism that shifts the sheet stacking position.
As shown in FIG. 2, the shift paper discharge mechanism 30 is provided corresponding to the first shift tray 102A side and the second shift tray 102B, respectively. Each shift paper discharge mechanism 30 moves the paper discharge roller 111A and the driven roller 113A in the direction of the arrow in FIG. 3 (arrow G1 corresponds to the front side of the stacker 100 in FIG. 2 and arrow G2 corresponds to the back side of the stacker 100). The sheet discharge position on the first shift tray 102A (or the second shift tray 102B) is shifted to the near side or the far side in FIG.

  That is, as shown in FIG. 3, the holder 51 and the holder 52 of the shift paper discharge mechanism 30 are connected to each other by the shaft 53 and the shaft 54, and move together in the directions of arrows G1 and G2. At this time, the rotating shaft 111AX that supports the paper discharge roller 111 (= corresponding to the paper discharge roller 111A and paper discharge roller 111B in FIG. 2; the same applies hereinafter) and the driven roller 113 (= the driven roller 113A and driven in FIG. 2). The rotation shaft 113AX that supports the roller 113B (the same applies hereinafter) is rotatably supported by the holder 51 and the holder 52. As a result, when the holder 51 and the holder 52 are integrated and shifted in the directions of arrows G1 and G2, the discharge roller 111 and the driven roller 113 are also moved in the directions of arrows G1 and G2.

  In parallel with this, the paper discharge roller 111 is rotated by the motor 55 regardless of the movement position in the directions of the arrows G1 and G2. That is, a driven gear 56 is attached to the paper discharge roller 111 via a rotation shaft 111AX, and this driven gear 56 is connected to the drive gear 60 rotated by the stepping motor 55 to the arrows G1 of the paper discharge roller 111A. Regardless of the movement position in the G2 direction, the discharge roller 111 is rotated in conjunction with the gears 57 and 58 and the belt 59, and the driven roller 113 is also rotated.

  The holder 51 is provided with a rack 61, and the rack 61 is connected to a shift motor 63 via a pinion 62. The discharge roller 111 and the driven roller 113 can be slid by a predetermined amount (for example, 10 mm) in the directions of arrows G1 and G2 from the center position shown in FIG.

  The home positions of the paper discharge roller 111 and the driven roller 113 are set at the center of the sheet conveyance path, and the light shielding plate 62A interlocked with the pinion 62 transmits detection light that constitutes the optical home position sensor S4. Whether or not the vehicle is in the home position is detected depending on whether or not the detection light from the part S4T to the detection light receiving part S4R is blocked. Then, by rotating the shift motor 63 by a predetermined amount with reference to the home position, the paper discharge roller 111A and the driven roller 113A move to a predetermined shift position.

Next, the configuration of the tip aligning portion 70 will be described.
FIG. 4 is an explanatory diagram showing the configuration of the tip alignment portion.
As shown in FIG. 4, the leading edge aligning portion 70 is a mechanism for aligning the leading edge of the sheet discharged onto the first shift tray 102A or the second shift tray 102B, and is in the directions of arrows H1 and H2 (FIG. 2). 4) and a stopper 71 that can be adjusted in position.

  The stopper 71 is attached to a slider 72, and the slider 72 is slidably guided by a shaft 73 extending in the arrow H1 direction as shown in FIG.

  The slider 72 is connected to a belt 76 that is stretched between pulleys 74 and 75. When the belt 76 is moved by the motor 77, the slider 72 moves in the direction of the arrow H1 together with the stopper 71, and the position thereof is adjusted. The slider 72 is provided with a shielding plate 78, and when the stopper 71 moves to the home position, the shielding plate 78 is detected by the optical home position sensor S5.

  The sheet that hits the stopper 71 when discharged to the first shift tray 102A is urged downward and rearward in the transport direction by the paddle 110A, and hits the abutting portion.

Next, the configuration of the main jogger mechanism 200 will be described.
FIG. 5 is an explanatory diagram showing the configuration of the main jogger of the stacker in FIG.
6 is a perspective view showing the configuration of the main jogger of the stacker in FIG.
FIG. 7 is an explanatory diagram showing the configuration of the alignment section of the main jogger.

  In the stacker 100 of the present embodiment, the main jogger mechanism 200 is provided with a total of two for the first shift tray 102A and the second shift tray 102B.

  Each main jogger mechanism unit 200 includes stepping motors 201 and 202 that control movement in the width direction (a direction that is perpendicular to the sheet discharge direction), a stepping motor 203 that controls movement in the vertical direction, and gears of the stepping motor 203. Detecting the meshed gear 204, the rotating shaft 205 to which the gear 204 is attached, the driving shaft 206 provided in parallel to the rotating shaft 205, the sliders 207F and 207R connected to the driving shaft 206, and the sliders 207F and 207R Sensors S6F and S6R, a filler 208 that indicates the rotation state of the rotary shaft 205 and is installed on the gear 204, and a sensor S7 that detects the filler 208.

  In this configuration, the main jogger mechanism 200 is driven so that the interval between the main jogger 210F and the main jogger 210R is widened or narrowed.

  Further, the main jogger mechanism unit 200 drives the main jogger 210F and the main jogger 210R in the vertical direction (the direction in which the main jogger mechanism unit 200 is separated from and in contact with the upper surface of the seat). The state in which the filler 208 is detected by the sensor S7 is the home position, and the main joggers 210F and 210R are in the lowered state position.

  In the state shown in FIG. 6, the rotation axis 205 rotates counterclockwise (CCW), so that the main joggers 210F and 210R rotate around the rotation axis 205, and the tips 210FT and 210RT draw an arc. To rise. Although the amount of rotation is arbitrary, in order to avoid a collision with another member, it is good to set it as about 50-60 degrees.

As shown in FIG. 6, the main joggers 210F and 210R are configured as plate-like bodies.
The aligning portions 211F and 211R are located at the lowermost part of the main joggers 210F and 210R, and the opposing surfaces are flat and orthogonal to the shift directions G1 and G2. The main joggers 210F and 210R are installed such that their lower ends are positioned below the abutting portion against which the sheet is abutted.

  As described above, by arranging the aligning portions 211F and 211R so that the opposing surfaces are flat surfaces orthogonal to the shift directions G1 and G2, the main joggers 210F and 210R are moved in the shift direction G1 or the shift direction G2. By moving, the sheet bundles can be aligned by reliably bringing the aligning portions 211F and 211R into and out of contact with the end face of the sheets stacked on the first shift tray 102A.

  As shown in FIG. 7, the main joggers 210 </ b> F and 210 </ b> R are arranged in order to avoid interference with the discharged paper when guiding the paper discharged from the paper discharge roller 111 </ b> A shown in FIG. The relief portions 212F and 212R are formed in a step shape so that the portions of the alignment portions 211F and 211R close to the rotation shaft 205 are wider than the facing interval between the alignment portions 211F and 211R.

  The main joggers 210F and 210R are configured to be pressed with the sliders 207F and 207R sandwiched between the bases. The positions of the sliders 207F and 207R prevent the main joggers 210F and 210R from dropping below a predetermined position. However, it is free to move upward.

Here, an operation when stacking sheets on the first shift tray 102A when the operation mode is the shift discharge mode will be described.
First, the main control unit 10 drives the drive unit 21 via the drive control unit 22 of the branch claw switching unit 20 to bring the branch claw N1 into a state in which a sheet can be conveyed to the third sheet conveyance path L3.
As a result, the sheet introduced into the stacker 100 by the entrance roller 114 (see FIG. 2) can be conveyed to the first shift tray 102A.

  In this case, the main joggers 210F and 210R provided on the first shift tray 102A side stand by at a receiving position with a predetermined facing interval that can receive a sheet (paper) discharged from the paper discharge roller 111A. ing.

  Every time a sheet (paper) is discharged by the paper discharge roller 111A and stacked on the first shift tray 102A, an operation of narrowing the facing distance between the main joggers 210F and 210R is performed, and the main joggers 210F and 210R are moved from the receiving position to the sheet ( After moving to the end surface position of the sheet, the operation of widening the facing interval is performed to return to the receiving position. By repeating this series of alignment operations, the end surfaces of the sheets (paper sheets) are aligned.

  The paper discharge roller 111A discharges a predetermined number of sheets constituting the first sheet bundle (paper bundle) stacked on the first shift tray 102A while repeating a predetermined amount of shift operation in the direction of arrow G1 for each sheet (paper). Exit. Thereafter, the main control unit 10 of the stacker 100 repeats a predetermined amount of shifting operation in the direction of the arrow G2, and stacks the next sheet bundle (sheet bundle) on the first shift tray 102A. When the shift direction is switched, the main joggers 210F and 210R move to the retreat rotation position, so that the aligning portions 211F and 211R are retracted. Under this state, the main joggers 210F and 210R perform a shift operation.

  For example, when the discharge roller 111A is shifted to the main jogger 210F side, the main jogger 210R is stacked on the back side surface of the discharge sheet stacked on the first shift tray 102A and on the first shift tray 102A. The sheet is disposed at a position that comes into contact with the upper surface of the sheet bundle (sheet bundle) that has been discharged and shifted last time.

  The other main jogger 210F is located on the front side surface of the sheets stacked on the first shift tray 102A, and takes the home position as the vertical position. Each time the paper discharge roller 111A shifts in the opposite direction, the arms 209F and 209R attached to the rotary shaft 205 rotate in the direction of pressing the bases of the main joggers 210F and 210R downward to move to the retreat position.

  Every time the shift operation is performed, the opposite alignment member is brought into contact with (placed on) the previously aligned sheet bundle (paper bundle), and the discharged sheet bundle (paper bundle) is aligned. At this time, the main joggers 210F and 210R set the friction coefficient so that the paper does not shift, so that the paper can be stably aligned. Therefore, it is preferable to form the main joggers 210F and 210R using a low-friction resin (PTFE or the like).

Further, the retreat amount (retreat distance) above the main joggers 210F and 210R is the retreat amount (retreat distance) from the home position where the filler 208 is detected by the sensor S7, and the amount is always constant.
In this case, if the uppermost surface + α (play) of the sheet bundle stacked on the first shift tray 102A is not moved (raised) from the home position, it interferes (contacts) with the stacked sheet bundle that is shifted. As a result, the aligned bundle will collapse.

  By the way, the value of the play α has an upper limit on the distance from the uppermost surface of the sheet bundle loaded on the first shift tray 102A to the uppermost position, which is a mechanical limit above the main joggers 210F and 210R. However, if the value of α is large, the margin for handling the curl or fold of the detection paper increases, but it takes time to return to the position (home position) where the next sheet (paper) can be received. For this reason, an optimum value is set in consideration of a trade-off with closing the sheet interval (shortening the sheet discharge interval).

FIG. 8 is an explanatory diagram of the configuration of the sub jogger mechanism.
The sub jogger mechanism 300 is a mechanism for aligning the leading ends of the sheets discharged onto the first shift tray 102A or the second shift tray 102B. Sub joggers 310F and 310R whose position can be adjusted in the width direction by the stepping motor 301 are provided. I have.

The sub joggers 310F and 310R are respectively attached to sliders 311F and 311R, and the sliders 311F and 311R are guided to be slidable on shafts 302 and 303 extending in the width direction. The sliders 311F and 311R are connected to a belt 306 that is bridged between the pulleys 304 and 305. When the belt 306 is driven by the stepping motor 301, the sliders 311F and 311R move in the width direction together with the sub joggers 310F and 310R.
When the sliders 311F and 311R move to the home position, they are detected by an optical home position sensor (not shown).

Next, an operation when stacking sheets on the second shift tray 102B when the operation mode is the shift discharge mode will be described.
First, the main control unit 10 drives the drive unit 21 via the drive control unit 22 of the branch claw switching unit 20 to move the branch claw N1 to the first sheet conveyance path L1 and second sheet conveyance path L2 side. It is assumed that it can be transported.

  Further, the main control unit 10 drives the drive unit 21 via the drive control unit 22 of the branch claw switching unit 20 to bring the branch claw N2 into a state in which a sheet can be conveyed to the second sheet conveyance path L2.

Further, the main control unit 10 drives the drive unit 21 via the drive control unit 22 of the branch claw switching unit 20 so that the branch claw N3 can be conveyed to the fifth sheet conveyance path L5 side. .
As a result, the sheet introduced into the stacker 100 by the entrance roller 114 is second-shifted via the second sheet conveying path L2 and the fifth sheet conveying path L5 (and, if necessary, the fourth sheet conveying path L4). It can be conveyed to the tray 102B.

  In this case, the main joggers 210F and 210R provided on the second shift tray 102B side stand by at a receiving position with a predetermined facing interval that can receive a sheet (paper) discharged from the paper discharge roller 111B. ing.

  Each time a sheet (paper) is discharged by the paper discharge roller 111B and stacked on the second shift tray 102B, an operation of narrowing the opposing distance between the main joggers 210F and 210R is performed to move the main joggers 210F and 210R from the receiving position to the sheet ( After moving to the end surface position of the sheet, the operation of widening the facing interval is performed to return to the receiving position. By repeating this series of alignment operations, the end surfaces of the sheets (paper sheets) are aligned. The operation of each part at this time is the same as that described in the case of the first shift tray 102A.

  Similarly, the retraction amounts (retraction distances) upward of the main joggers 210F and 210R are the same as the retraction amounts (retraction distances) from the home position where the filler 208 is detected by the sensor S7. It becomes. Similarly, the play α is set to an optimum value in consideration of the trade-off between the margin and the space between the sheets (shortening the paper discharge interval).

  By the way, when stacking sheets having different image formation contents or sheet sizes between the first shift tray 102A and the second shift tray 102B, there is no problem, but the first shift tray 102A and the second shift tray 102B are not problematic. When sheets of the same size having the same image formation content are stacked, it is desirable that the sheets are stacked in the same direction when taken out.

  That is, when the sheets are stacked on the second shift tray 102B, when the sheets are directly conveyed from the second sheet conveyance path L2 to the fifth sheet conveyance path L5 via the branching claw N3, the sheets are loaded on the first shift tray 102A. The front and back of the stacked sheets are reversed.

Therefore, in such a case, the branching claw N3 is switched from the fifth sheet conveying path L5 side to the fourth sheet conveying path L4 side, and the sheet once conveyed to the fourth sheet conveying path L4 is branched in FIG. The sheet is directly conveyed to the fifth sheet conveying path L5 through the lower side of the claw N3 and stacked on the second shift tray 102B.
As a result, the paper is discharged in the same direction as when it was discharged to the first shift tray 102A side.

  As described above, according to the present embodiment, the sheet alignment accuracy in the front-rear direction of the sheet conveyance direction can be ensured, and the conveyance path (= first conveyance path) for conveying the sheet to the first shift tray 102A; Since the transport path (= second transport path) for transporting the sheet to the second shift tray 102B is only selectively switched, the transport system is the same for each tray, and a reduction in productivity can be suppressed.

In the present embodiment, since the number of tray operations is reduced by merely lowering the operation of the shift tray during the sheet passing, the long life of the first tray lifting motor 109A and the second tray lifting motor 109B is increased. Can be achieved.
Further, it is possible to save energy by reducing the operations of the first shift tray 102A and the second shift tray 102B.

  By the way, in the case of an apparatus in which the paper discharge tray is outside and the user can always touch the paper being discharged, there is a possibility that the user picks up the paper in the paper discharge tray while the paper is being discharged. Therefore, it has been necessary to constantly monitor the position of the tray using a sensor for detecting the position of the tray to detect that the paper has been removed, and to raise the tray when the paper is removed.

  In the sheet stacking apparatus according to the present embodiment, the first shift tray 102A and the second shift tray 102B, which are discharge trays that move in the vertical direction, are accommodated in the casing and do not open the door provided in the casing. As long as the user cannot remove the sheet from the first shift tray 102A or the second shift tray 102B. In addition, when the paper is extracted, it is only necessary to raise the sheet after the door is closed. Therefore, it is not always necessary to monitor the positions of the first shift tray 102A and the second shift tray 102B.

  Further, during the sheet passing, the sheet loaded on the first shift tray 102A and the paddle 110A are repeatedly contacted. When the first shift tray 102A is raised, the contact area and the contact pressure between the sheet and the paddle 110A are increased. Therefore, the material of the paddle 110A is easily transferred to the paper. In the present embodiment, since the first shift tray 102A only performs the lowering operation, the contact area between the sheet and the paddle 110A is reduced when the first shift tray 102A is moved, and the contact pressure is also reduced. It is also possible to reduce contamination of the (paper cutting section). The same applies to the second shift tray 102B.

  Furthermore, in the present embodiment, when the sheets are stacked, the operation is only to lower the first shift tray 102A or the second shift tray 102B. Therefore, as compared with the conventional case where the tray is raised after the lowering. Thus, although the paper surface is at a low position, the lower end of the first shift tray 102A or the second shift tray 102B is lowered because the leading ends of the main joggers 210F and 210R are located below the abutting portion against which the paper abuts. Even if it is large, there is an advantage that the sheet aligning operation can be performed reliably.

In addition, the said embodiment is an example of suitable implementation of this invention, and this invention is not limited to this.
For example, in the above-described embodiment, the configuration in which the sheet stacking device is independent of the image forming apparatus has been described as an example, but the configuration may be integrated with the image forming apparatus.

  In the above description, when the first shift tray 102A and the second shift tray 102B have the same stacking direction, the stacking direction is switched on the sheet stacking apparatus 100 side. Thus, by notifying in advance that the first shift tray 102A is full, the image forming apparatus can invert and discharge the sheets when the stacking of sheets is switched to the shift tray 102B. It is.

In addition, when a sheet different from the sheet stacked on the first shift tray 102A is transported, the transport path is switched and the sheet is discharged to the second shift tray 102B. Is possible.
As described above, the present invention can be variously modified.

DESCRIPTION OF SYMBOLS 10 Main control part 20 Branch nail | claw switching part 30 Shift discharge mechanism 70 Tip alignment part 100 Stacker (sheet stacking apparatus)
102A First shift tray (first tray)
102B Second shift tray (second tray)
200 Main jogger mechanism 300 Sub jogger mechanism (front-rear direction drive mechanism)
500 Image forming apparatus L2 Second sheet conveyance path (second conveyance path)
L3 Third sheet conveying path (first conveying path)
L4 Fourth sheet conveying path (second conveying path)
L5 Fifth sheet conveyance path (second conveyance path)
N1-N3 branch claw

Claims (4)

A sheet stacking apparatus having a sheet aligning unit that receives a sheet to be processed and aligns the sheet by bringing a movable fence into contact with an end of the sheet by a driving mechanism,
A first tray on which the sheets can be stacked;
A first tray that is connected to the first tray along the sheet conveyance direction and that can stack the sheets as a separate tray from the first tray or as a single tray integrated with the first tray. Two trays,
In the first tray or the second tray, a front-rear direction drive mechanism that drives and abuts a front-rear movable fence to an end in the front-rear direction with respect to the sheet conveyance direction;
A first conveyance path for conveying the sheet to the first tray;
A second conveyance path for conveying the sheet to the second tray;
Transport path switching means for selectively switching the first transport path or the second transport path;
Equipped with a,
Among the first tray and the second tray, the tray disposed on the upstream side in the sheet conveyance direction is supplied with the sheet from the upstream side through a corresponding conveyance path,
To the tray arranged on the downstream side, a sheet is supplied from the downstream side through a corresponding conveyance path,
A sheet post-processing apparatus can be connected to the subsequent stage of the sheet stacking apparatus, and a conveyance path provided on the downstream side of the pair of trays constitutes a sheet conveyance path to the sheet post-processing apparatus. , Functioning as a stacking direction changing means for enabling stacking of the sheets in the same direction as the sheets supplied to the tray disposed on the upstream side,
A sheet stacking apparatus characterized by that.   The stacking direction changing means reverses the front and back of the sheet in a conveyance path provided on the downstream side of the pair of trays.
  The sheet stacking apparatus according to claim 1.   The first tray and the second tray are respectively placed on elevators that can be lifted and lowered by a lifting motor, and are only lowered during sheet passing.
  The sheet stacking apparatus according to claim 1 or 2.   The first tray and the second tray are accommodated in a housing having a door for taking out the sheet from the first tray or the second tray, and when the paper is pulled out, the door Lifted by the elevator after being closed,
  The sheet stacking apparatus according to claim 3.

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