JP5347852B2 - Sheet stacking apparatus, image forming apparatus, and sheet stacking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain sheet dislocation on a tray only by control of an existing member in a stacker. <P>SOLUTION: Even after completing paper ejection of the stacking final paper, three registering means in total of a distal end stopper and main joggers, hold a sheet in a sheet abutting position (S104-1). The existence of a lowering request from a user to a shift tray is determined in this state (S104-2), and when the lowering request is output (S104-2: YES), after a specific time (for example, time 30 sec until the sheet is settled down)passes (S104-3), when the specific time is passed (S104-3: YES), the distal end stopper and the main joggers allowed to abut on the sheet are moved to a retreat position (S104-4), and after completing the movement of the distal end stopper and the main joggers, lowering of the shift tray is started (S104-5). When the lowering of the shift tray is completed (S104-6), printing finishes. Further, in abutment on the sheet, among the distal end stopper and the two main joggers, at least one preferably abuts on the sheet. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a large-capacity sheet stacking apparatus that sorts and accumulates sheet members (herein, simply referred to as “sheets”) such as paper, recording paper, and sheet-like recording medium that are carried in, and the sheet. The present invention relates to an image forming apparatus provided with a stacking apparatus integrally or separately, and a sheet stacking method on the sheet stacking apparatus.

  2. Description of the Related Art A large capacity sheet stacking device that is connected to a copying machine, a printer, or a subsequent stage of a printer and stacks a large number of sheets discharged from an image forming apparatus or sends the sheet to a subsequent post-processing apparatus or bookbinding apparatus is known. . In such a large-capacity sheet stacking apparatus (hereinafter referred to as a stacker), sheets can be stacked on a horizontal tray, taken out from the apparatus as a carriage with the sheets placed on the tray, and transported. In order to satisfy such a function, the tray is moved up and down by the support member.

  The support member can be lowered to a position where it does not come into contact with the tray, and the tray is fixed on the carriage at a position where the support member is separated from the tray so that it can be taken out and transported. When the sheet is loaded on the next tray, the support member is lifted by placing the carriage in the specified position, and the tray is supported from below and lifted to the sheet receiving position. Further, in order to satisfy the sheet alignment accuracy on the tray, a leading edge alignment mechanism is disposed in the sheet conveyance direction, and a main jogger mechanism and a sub jogger mechanism are disposed in the sheet width direction.

  However, the conventional stacker has a problem that alignment accuracy is deteriorated when the tray is lowered after completion of sheet stacking (stacked sheets are displaced). The cause of the problem is that the coated paper has a specially processed sheet surface, and it is difficult for air between the sheets to escape immediately after ejection, the friction between the sheets is not stabilized by the air layer, and the tray surface (the sheet on the tray) Since the (placement surface) is horizontal, the sheet is displaced by a slight vibration. In addition, the thicker the sheet, the stronger the sheet and the slower the adhesion between the sheets.

  FIG. 15 is an explanatory diagram showing a mechanism of occurrence of stacking misalignment in coated paper, FIG. 16 is an explanatory diagram showing the direction in which the sheet is misaligned, and FIG. 17 is an explanatory diagram showing each position of the aligning means relative to the sheet.

  As shown in FIG. 15, the air between the sheets is difficult to escape from the upper part of the sheet bundle PB immediately after the stacking on the stacking means (shift tray 102 described later) is completed. This is a characteristic of coated paper, and is due to the fact that a paint is applied to the surface of the sheet to enhance aesthetics and smoothness. Further, since the friction between the sheets is not stable due to the presence of the air layer AL for a long time, the sheets are displaced from the main body of the sheet bundle PB only by a slight vibration. The direction in which the sheet slips is not a fixed direction, but may be in any direction. In FIG. 16, the tip stopper 71 and the main jogger 210 are shown, and the arrows are shown in the main jogger 210 directions D1 and D2 and the tip stopper 71 direction (sub-scanning direction) D3. It moves in any direction on the paper discharge surface in any composite direction of the directions D1 to D3.

  FIG. 17 shows the operating position of the aligning means (here, the main jogger 210 and the tip stopper 71). (A) is a sheet receiving position, (b) is a sheet alignment position, and (c) is a retracted position. The position (c) is a state in which the front end stopper 71 and the main jogger 210 are retracted to a position where they do not interfere with the sheets stacked on the shift tray 102 in preparation for removing the carriage when printing is completed. The position of (c) is because the upper sheet contacts the leading end stopper 71 or the main jogger 210 when the carriage is taken out when the sheet is in a large stack state. The main jogger 210 and the sub jogger 310 (to be described later) of the aligning means move to the position (c) when the shift tray 102 is processed, and prevent the interference with the sheet by lifting the jogger upward. In normal control, since the sheets are taken out after the stacking is completed, the front end stopper 71, the main jogger 210, and the sub jogger 310 are retracted to the position (c), and the movement of the sheets cannot be suppressed.

  On the other hand, in order to remove the air layer AL generated between the above-mentioned sheets, there is a method of forcibly removing it by waiting for a time to elapse until air naturally escapes or by physically pressing from the upper part of the sheet. . However, in the method of pressing the sheet from the upper part, there is a need to add a member for newly pressing and a mechanism therefor, and in addition, there is a problem of hindering consistency. In addition, when a large number of sheets with high temperature are stacked, such as when the sheets are printed with double-sided color printing, a phenomenon in which ink sticks to each other due to the weight of the sheets (blocking phenomenon) occurs. The method of pressing the sheet from the top also has a problem of promoting this blocking phenomenon.

  In the method of waiting until the air naturally escapes, there are variations in the type of coated paper and the same paper, so it takes 15 to 30 seconds for the sheet to be in a state that does not shift due to vibration. From the above, it is best to stop the stacking means for 15 to 30 seconds. However, as a specification of the stacker, a descending start signal (when the user presses the button to take out the sheet) When the signal is generated, it is necessary to lower the loading means immediately. For this reason, since the user waits for 15 to 30 seconds after the user instructs the descent start, it is not the best method for the specification to stop the stacking means.

  Therefore, for example, an invention described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-059882) has been proposed as a technique for dealing with such problems. In the present invention, sheet conveyance is performed for the purpose of suppressing slippage and skewing during conveyance due to a decrease in the friction coefficient of the sheet surface, and conveyance failure associated therewith, and further alignment failure during sheet alignment and stacking failure during sheet stacking. A technique for changing the control of the aligning means for a specific sheet together with the control of time is disclosed.

  In the invention described in Patent Document 1, it is not configured to eliminate sheet misalignment or sheet misalignment only by sheet handling control on a horizontal sheet placement surface such as a stacker. It is intended to eliminate sheet misalignment or misalignment including control. For this reason, the objects to be controlled are large-scale, and naturally the cost has to be high.

  Therefore, a problem to be solved by the present invention is to be able to suppress sheet deviation on the tray only by controlling existing members in the stacker.

  In order to solve the above-described problem, the first means is a sheet stacking apparatus including a sheet stacking unit that stacks a sheet conveyed by the sheet conveying unit on a tray that can be moved up and down, and aligns the main scanning direction of the sheet. Main scanning alignment means, sub-scanning alignment means for aligning the sub-scanning direction of the sheet, and control means for controlling the ascending / descending operation of the main scanning alignment means, the sub-scanning alignment means, and the sheet stacking means. When the last sheet of the sheet is discharged to the sheet stacking unit and the sheet stacking is completed, when the sheet stacked on the sheet stacking unit is a special sheet, the control unit The lowering of the sheet stacking unit is started in a state where at least one of the main scanning alignment unit and the sub-scanning alignment unit is in contact with the sheet on the sheet stacking unit.

  The second means includes operating means for instructing start of lowering of the sheet stacking means in the first means, and the control means detects the lowering start signal based on the instruction of the operation means and then detects the sheet stacking The alignment means is brought into contact with the sheet before the start of lowering of the means.

  The third means is characterized in that, in the first means, the control means continues the contact of the aligning means to the sheet from the time when the sheet stacking is completed.

  A fourth means is any one of the first to third means, characterized in that the control means lowers the descending speed of the stacking means for a certain period of time from the start of descending with respect to normal operation.

  The fifth means comprises the operation means for the user to instruct the lowering of the sheet stacking means in the fourth means, and a signal requesting the lowering of the sheet stacking means is continuously sent from the operating means to the control means. In such a case, the control means stops control of the special paper of the alignment means and the sheet stacking means.

  A sixth means is characterized in that the image forming apparatus includes a sheet stacking apparatus according to any one of the first to fifth means.

  The seventh means is characterized in that, in the sixth means, an operation means is provided on the image forming apparatus main body side, and an operation input to the sheet stacking apparatus is possible from the image forming apparatus main body side.

  The eighth means is a sheet stacking method for stacking the sheet conveyed by the sheet conveying means on the sheet stacking means that can be moved up and down, the main scanning alignment means for aligning the main scanning direction of the sheet, and the sub scanning of the sheet Sub-scanning alignment means for aligning directions, and the final sheet of the sheet is discharged to the sheet stacking means, and when the sheet stacking is completed, the sheet stacked on the sheet stacking means is a special sheet. In this case, the lowering of the sheet stacking unit is started in a state where at least one of the main scanning alignment unit and the sub-scanning alignment unit is in contact with the sheet on the sheet stacking unit. .

  In the embodiments described later, the sheet conveying means is the entrance roller 114, the sheet conveying roller 111 and the driven roller 113, the sheet stacking means is the shift tray 102, the sheet stacking apparatus is the stacker 100, and the main scanning alignment means is the main jogger. 210 and the sub jogger 310, the sub-scanning alignment means is the tip stopper 71, the control means is the CPU (not shown), the operation means is the operation display section (not shown), the image forming apparatus is PR, and the operation means of the image forming apparatus is shown. Corresponding to the operation display section that does not.

  According to the present invention, even if vibration occurs due to the lowering of the stacking unit after the stacking of the sheets is completed, the alignment unit is in contact with the sheet, so that the sheet is not displaced, and the existing member in the stacker Only by this control, sheet misalignment on the tray can be suppressed.

1 is a diagram illustrating a schematic configuration of a large-capacity sheet stacking apparatus (stacker) according to an embodiment of the present invention. It is a perspective view which shows the shift conveyance machine rear part in the stacker of FIG. It is a perspective view which shows the front end alignment mechanism in the stacker of FIG. FIG. 2 is a view showing a main jogger mechanism in the stacker of FIG. FIG. 2 is a view showing a main jogger mechanism in the stacker of FIG. It is a figure which shows the main jogger mechanism in the stacker of FIG. 1, and is a perspective view of a main jogger. FIG. 2 is a diagram illustrating a sub jogger mechanism in the stacker of FIG. 1 and is a perspective view seen from the upstream side in the sheet discharge direction. 6 is a flowchart illustrating a control procedure of sheet misalignment suppression control according to the first embodiment. It is a flowchart which shows the detail of the control for special paper of FIG. 8, and normal control. It is a flowchart which shows the other example of the detail of the control for special paper of FIG. 8, and normal control. FIG. 9 is a flowchart showing still another example of details of the special paper control and the normal control in FIG. 8. FIG. 10 is a flowchart illustrating a control procedure of sheet misalignment suppression control according to the second embodiment. It is a flowchart which shows the control procedure of the modification of FIG. 12 is a flowchart illustrating a control procedure of sheet misalignment suppression control according to the third embodiment. It is explanatory drawing which shows the mechanism of stacking | deviation deviation generation | occurrence | production with the coated paper in a prior art example. It is explanatory drawing which shows the direction where the sheet | seat in a prior art example slips. It is explanatory drawing which shows each position with respect to the sheet | seat of the alignment means.

  The present invention is designed to prevent misalignment caused by vibration when coated paper after completion of stacking starts to descend the stacking tray without adding a new member to the current stacker configuration. When the paper is discharged onto the tray, the control is performed to maintain the state of the sheets stacked for a predetermined time before the tray descends, thereby suppressing the misalignment of the stacked sheets. Specifically, it has the following characteristics during the process of lowering the tray after completion of loading special paper. In short, the present invention is characterized in that the tray control and alignment control before or during the tray lowering are changed only in the case of special paper to prevent the misalignment of the stacked sheets of special paper.

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

  FIG. 1 is a diagram showing a schematic configuration of a large-capacity sheet stacking apparatus (hereinafter referred to as “stacker”) according to an embodiment of the present invention. In the figure, a stacker 100 is basically composed of a stacker body 100A, an elevating mechanism 100B, an elevating drive mechanism 100C, a transport mechanism 100D, a shift tray 102, and a carriage 109. For example, the stacker 100 is connected to the rear stage of the image forming apparatus PR, and Used as one of the post-processing devices.

  As shown in FIG. 1, the elevating mechanism 100B is provided perpendicular to the four corners of the stacker body 100A in plan view, and includes a pair of upper and lower timing pulleys 105, a timing belt 104 stretched between the timing pulleys 105, and an elevator ( Support member) 103, and the shift tray 102 is supported by the elevator 103. That is, the four corners of the elevator 103 are suspended by a total of four timing belts 104, and each timing belt 104 is wound around a corresponding four timing pulleys 105. The central portion of the elevator 103 is a notch 103a, and the carriage 109 will be described later, but can be pulled out from the stacker main body 100A from the open portion on the front surface of the notch 103a with the shift tray 102 mounted. Yes.

  The elevating drive mechanism 100C is a mechanism for elevating the elevator 103, and includes a timing pulley 115, tension pulleys 116 and 117, a timing belt 115 spanned between these pulleys, and a tray that rotationally drives the timing belt 115. The elevating motor 108 and a gear train 107 that transmits the driving force of the tray elevating motor 108 to the driving-side timing pulley 105 via the worm gear 106 are provided.

  The transport mechanism 100D discharges the sheet transported from the image forming apparatus PR side to the shift tray 102 or transports the sheet to a subsequent sheet processing apparatus. The transport mechanism 100D includes first to third transport paths L1, L2, and L3. , The entrance roller 114, the first branch claw 120 that switches to either the second transport path L2 or the third transport path L3, and the second branch that switches to either the first transport path L1 or the second transport path L2. Claw 121. The first conveyance path L1 is a conveyance path for discharging a sheet to the proof tray 101, and is a conveyance path from the second branch claw 121 to the proof tray 101. The second conveyance path L2 is a conveyance path for conveying the sheet to the subsequent sheet processing apparatus, and is a conveyance path from the entrance portion to the paper discharge portion. The third conveyance path L3 is a conveyance path for discharging a sheet to the shift tray 102, and is a conveyance path from the first branching claw to the discharge to the shift tray 102.

  Note that a conveyance roller (paper discharge) 111 for discharging a sheet to the shift tray 102 is provided at the most downstream portion in the sheet conveyance direction of the third conveyance path L3, and the conveyance roller 111 is urged by a spring to be pressed. Then, a driven roller 113 that is driven is provided, and a sheet is nipped between these rollers 111 and 113. Further, first and second sheet conveyance path sensors S1 and S2 are provided along the sheet conveyance path, and a sheet surface sensor S3 is disposed in the vicinity of the sheet discharge portion of the conveyance roller 111. A plurality of conveyance rollers 122 are arranged in each of the sheet conveyance paths L1, L2, and L3 and are driven by a driving mechanism (not shown) to convey the sheet to a predetermined position.

  In FIG. 1, a jogger 210 and a sub jogger 310 for aligning sheets that are discharged to the shift tray 102 and stacked are provided above the lifting drive mechanism 100C.

  A sheet discharged from an image forming apparatus PR such as a copier installed adjacent to the stacker body 100A of the stacker 100 configured as described above is introduced from the direction of arrow A. The stacker 100 in this embodiment can select an operation mode of a proof discharge mode, a straight discharge mode, and a shift discharge mode.

  The proof paper discharge mode is an operation mode in which a sheet is guided and stacked on the proof tray 101 through the sheet conveyance path L1. In the proof discharge mode, the sheet is conveyed by the conveyance rollers 1, 2, 3, and 4 and is discharged to the proof tray 101 (in the direction of arrow B in FIG. 1).

  The straight sheet discharge mode is an operation mode in which a sheet is guided to another apparatus such as a second stacker, a post-processing apparatus, a bookbinding apparatus, and a finisher provided in the subsequent stage of the stacker 100 through the sheet conveyance path L2. In the straight sheet discharge mode, the sheet is transported by a plurality of transport rollers 122 and sent to a subsequent apparatus.

  The shift discharge mode is an operation mode in which sheets are discharged and stacked on the shift tray 102 through the sheet conveyance path L3. In the shift discharge mode, sheets are stacked at different shift positions on the shift tray 102. In the shift discharge mode, the sheet is conveyed by the entrance roller 114 and the shift discharge roller 111 and discharged to the shift tray 102.

  The shift tray 102 is placed on an elevator 103 that can be raised and lowered. As described above, the four corners of the elevator 103 are suspended by a total of four timing belts 104, and each timing belt 104 is wound around a corresponding four timing pulleys 105. These timing pulleys 105 are connected by a worm gear 106 and a gear train 107 composed of a plurality of gears, and are synchronously driven by the driving force of the tray lifting / lowering motor 108 to hold the shift tray 102. The elevator 103 is moved up and down. In the elevating drive mechanism 100C in this embodiment, the power transmission system is via the worm gear 106, so that the shift tray 102 can be kept at a fixed position when the tray elevating motor 108 is stopped.

  When the elevator 103 of the elevating mechanism 100B is lowered to the vicinity of the lowest position by driving of the elevating drive mechanism 100C, the shift tray 102 is placed on the carriage 109, and the elevator 103 is further lowered to restrain the elevator 103. Is released, and the sheet loaded on the shift tray 102 can be carried out by the carriage 109.

  Reference numeral 110 denotes a paddle that rotates in conjunction with the conveyance roller 111 in the sheet conveyance path L3, and strikes the rear end portion of the sheet discharged on the shift tray 102 or the sheet bundle stacked on the shift tray 102. Press down. In addition, a filler 112 is provided so that the top surface of the sheet stacked on the shift tray 102 is in contact with the leading end, and the filler 112 is pushed up when the sheet stacking surface becomes high. The optical paper surface sensor S <b> 3 detects the stack height of the sheets on the shift tray 102 based on the movement of the filler 112. Since such a detection mechanism and an elevating mechanism are provided, in the stacker 100 according to the present embodiment, when the paper surface sensor S3 is ON, the shift tray 102 is lowered by the tray elevating motor 108 and the paper surface sensor S3. Is turned OFF, the tray lifting / lowering motor 108 is stopped. Accordingly, every time the paper surface sensor S3 is turned on by the sheets stacked on the shift tray 102, the shift tray 102 is lowered by a predetermined distance. As a result, the distance between the upper surface of the uppermost sheet of the shift tray 102 and the nip between the conveying roller 111 and the driven roller 113 is always within a certain range. In addition, a full sensor (not shown) is provided near the lowermost part of the elevator 103 in the descending direction, and the shift tray 102 is sequentially lowered by stacking of sheets, and when the full sensor detects the lowest position of the elevator 103, the shift discharge is full. It becomes.

  The entrance sensor S1 is a sensor that is provided at the sheet carry-in entrance and detects passage of the sheet at the entrance. The second sheet transport path sensor S2 detects passage of the sheet in the third transport path L3. Sensor (hereinafter referred to as “paper ejection sensor”). The entrance roller 114 has a function of carrying a sheet conveyed from the image forming apparatus PR into the stacker body 100A.

  The sheet discharged onto the shift tray 102 is aligned in the sheet width direction by the jogger 210 and the sub jogger 310, and the sheet conveyance direction is aligned by the leading end stopper 71.

  In FIG. 1, the stacker 100 is directly connected to the subsequent stage of the image forming apparatus PR. However, the stacker 100 may be disposed at the subsequent stage of another stacker or the subsequent stage of another sheet processing apparatus. In some cases, other stackers or finishers may be connected. The image forming apparatus PR may be any known image forming apparatus such as a known copying machine such as an electrophotographic method or a droplet discharge method, a printer, a plotter copying machine, or a digital multifunction peripheral. It is not limited.

2. Shift Mechanism FIG. 2 is a perspective view showing a shift transport mechanism. In the figure, the shift transport mechanism 50 moves the transport roller 111 and the driven roller 113 by a predetermined amount in the directions of arrows G1 and G2 in FIG. 2 (the arrow G1 is the front side of the stacker 100 and the arrow G2 is the back side of the stacker 100). By doing so, the sheet discharge position on the shift tray 102 is shifted to the near side or the far side. That is, the transport roller 111 and the driven roller 113 are connected to holders 51 and 52 that move in the direction of the arrow and shafts 53 and 54 that connect them. The transport roller 111 is driven and rotated by the motor 55 regardless of the movement position in the directions of the arrows G1 and G2. That is, the driven gear 56 attached to the conveyance roller 111 is irrespective of the movement position of the conveyance roller 111 in the arrow direction with respect to the drive gear 60 driven by the stepping motor 55 via the gears 57 and 58 and the belt 59. Mesh.
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 transport roller 111 and the driven roller 113 are slid by a predetermined amount (10 mm) in the directions of arrows G1 and G2 with the position in FIG. 2 as the center position. The home positions of the transport roller 111 and the driven roller 113 are set at the center position, and are detected by the optical home position sensor S4. By rotating the pulse motor 63 by a predetermined amount with reference to the home position, the transport roller 111 and the driven roller 113 move to the shift position. Reference numeral 99 denotes an end fence that regulates the rear end of the sheet in the shift tray 102.

3. Tip Alignment Mechanism FIG. 3 is a perspective view showing the tip alignment mechanism. In the drawing, a leading edge aligning mechanism 70 is a mechanism for aligning the leading end of the sheet discharged onto the shift tray 102, and a leading end stopper 71 that can be adjusted in the direction of arrow H, which is a direction parallel to the sheet conveying direction. It has. The tip stopper 71 is attached to a slider 72, and the slider 72 is slidably guided by a pair of shafts 73 having an axial center extending in the arrow H direction as shown in FIG. The slider 72 is connected to a belt 76 that is stretched between pulleys 74 and 75. Then, by driving the belt 76 by the motor 77, the slider 72 moves in the arrow H direction together with the tip stopper 71, and the position of the tip stopper 71 is adjusted.
The slider 72 is provided with a shielding plate 78, and when the tip stopper 71 moves to the home position, the shielding plate 78 is detected by the optical home position sensor S5.

4). Main Jogger Mechanism FIGS. 4 to 6 are views showing the main jogger mechanism. FIG. 4 is a front view seen from the sheet discharge direction, FIG. 5 is a perspective view, and FIG. 6 is a perspective view of the main jogger. In these drawings, a main jogger mechanism 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 a stepping motor. A gear 204 meshing with the gear 203, a rotating shaft 205 to which the gear 204 is attached, a driving shaft 206 parallel to the rotating shaft 205, first and second sliders 207F and 207R connected to the driving shaft 206, The sensors S6F and S6R that detect the first and second sliders 207F and 207R, the filler 208 provided in the gear 204 that indicates the rotation state of the rotating shaft 205, and the sensor S7 that detects the filler 208 are configured. The first and second main joggers 210F and 210R are widened between the two. As such, also move to up and down them. The position where the sensor 208 detects the filler 208 is the home position, and the first and second main joggers 210F and 210R are in a lowered state. In the present embodiment, each part located on the front side of the apparatus is distinguished by attaching an F suffix, and each part located on the far side is assigned an R suffix.

  The first and second main joggers 210F and 210R are formed of plate-like bodies, and the first and second alignment portions 211F and 211R provided respectively are located at the lowermost portions of the main joggers 210F and 210R, and The opposing surface is a flat surface orthogonal to the shift directions G1 and G2.

  As described above, the first and second aligning portions 211F and 211R are configured by flat surfaces whose opposing surfaces are orthogonal to the shift directions G1 and G2, thereby shifting the first and second main joggers 210F and 210R. By moving in the directions G1 and G2, the first and second aligning portions 211F and 211R can be reliably brought into and out of contact with the end surfaces of the sheets stacked on the tray 102, and the sheet bundle can be aligned.

  As shown in FIG. 6, the first and second main joggers 210F and 210R are arranged so that the sheets discharged from the conveying roller 111 shown in FIG. 1 are within the facing distance between the first and second main joggers 210F and 210R. In order to avoid interference with the sheet discharged when being guided to the top, the upper portions of the first and second aligning portions 211F and 211R are formed at a wider interval than the facing interval between the aligning portions 211F and 211R. The first and second relief portions 212F and 212R are provided. The first and second main joggers 210F and 210R are configured such that the roots are sandwiched and pressed by the first and second sliders 207F and 207R, respectively, and depending on the positions of the first and second sliders 207F and 207R. The first and second main joggers 210F and 210R do not hang down below a predetermined state, but can move freely in the upward direction.

  When the first and second main joggers 210F and 210R receive a sheet discharged from the conveying roller 111, the first and second main joggers 210F and 210R stand by in a state of facing each other at a receiving position with a predetermined interval. In this state, every time a sheet is discharged from the conveying roller 111 and stacked on the tray 102, the opposing interval is set from the receiving position, moved to a position where it abuts against the sheet end surface, and then moved so as to widen the opposing interval. Return to the receiving position. By repeating this series of aligning operations for each sheet discharged, the end faces of the sheets are aligned.

  The conveyance roller 111 repeats a predetermined number of sheets constituting the first sheet bundle while repeating the 10 mm shift operation in the arrow G1 direction for each sheet, and then repeats the 10 mm shift operation in the arrow G2 direction to stack the next sheet bundle. To go. When the shift direction is switched, the first and second main joggers 210F and 210R move to the retracted rotation position to enter the aligning member retracted state. Under this retracted state, the transport roller 111 performs a shift operation.

  For example, when the transport roller 111 shifts to the first main jogger 210F side, the second main jogger 210R abuts on the back side of the discharged sheets stacked on the shift tray 102 and on the front “part” sheet bundle. Will be placed at the position. The first main jogger 210F is located on the front side surface of the sheets stacked on the shift tray 102, and takes the home position as the vertical position. Each time the shift operation of the transport roller 111 is reversed, the rotation shaft 205 is replaced with the first and second arms 209F and 209R (FIG. 5) attached to the rotation shaft 205, the first and second main joggers 210F, The base is moved to the retracted position by rotating the base of 210R downward. Each time a shift operation occurs, the opposite side aligning member is brought into contact with (placed on) the preceding “part” sheet bundle to align the discharged sheet bundle. At this time, the first and second main joggers 210 </ b> F and 210 </ b> R are set to a friction coefficient that does not cause the sheet to shift, so that the sheets can be stably aligned.

  The retraction amounts of the first and second main joggers 210F and 210R are retraction amounts from the home position where the fillers 208 are detected by the sensors S6F and S6R, and therefore the increase amount is always a constant amount. If the uppermost surface + α of the discharged bundle is not moved (raised) from the home position, it interferes (contacts) with the stacked sheet bundle that is shifted, and the aligned bundle is broken. + Α is a position between the uppermost position, but if the α value is large, the margin to cope with the curl and fold of the discharged sheet increases, but the return when the next sheet is accepted when the gap between the sheets is jammed. It will take time.

5. Sub-jogger mechanism The sub-jogger mechanism 300 shown in FIG. 7 is a mechanism for aligning the leading end of the sheet discharged onto the shift tray 102. The first and second positions that can be adjusted in the width direction by the stepping motor 301 are provided. Sub-joggers 310F and 310R. The first and second sub joggers 310F and 310R are attached to the first and second sliders 311F and 311R, respectively, and the first and second sliders 311F and 311R have their axes along the width direction of the sheet. Are slidably guided by two parallel shafts 302 and 303 arranged in parallel. The first and second sliders 311F and 311R are connected to a belt 306 that is stretched between the first and second pulleys 304 and 305.

  With this configuration, when the belt 306 is driven by the stepping motor 301, the first and second sliders 311F and 311R move in the width direction together with the first and second sub joggers 310F and 310R. When the second slider 311R moves to the home position, it is detected by an optical home position sensor (not shown).

  The entire stacker 100 and each part are controlled by a CPU (not shown). The CPU develops a program stored in a ROM (not shown) in a RAM (not shown), executes the program while using the RAM as a work area and a data buffer, and controls each unit of the stacker 100 including the motors. The stacker 100 includes an operation display unit (not shown) so that the user can instruct the lowering of the sheet stacking unit from the operation display unit. The stacker 100 can also be controlled by an operation input from the operation display unit of the preceding image forming apparatus PR, and the image forming apparatus PR can instruct to lower the sheet stacking unit.

  Hereinafter, the control procedure of sheet deviation suppression control will be described for each embodiment. In the following description, the same control procedures are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. In addition, any control is executed by the CPU according to a program stored in the ROM.

  FIG. 8 is a flowchart illustrating a control procedure of sheet misalignment suppression control according to the first embodiment. In the figure, the stacker 100 discharges the sheet to the shift tray 102 which is a stacking unit in the shift mode setting (step S101). In step S1, with respect to the shift operation described with respect to the shift mechanism 2 described above, the leading edge is aligned with the leading edge alignment mechanism 3, and the shift tray 102 aligns with the main jogger 210 described with the main jogger mechanism 4. The action is executed. Although not described in detail here, the sub jogger 310 operates when the use condition of the sub jogger 310 is met.

  When the shift operation and the alignment operation are executed by the set shift mode and the final paper is discharged onto the shift tray 102 (step S102), the final paper conveyed from the image forming apparatus PR is set to the special paper setting. It is determined whether or not (step S103). Whether or not the paper is special paper is determined from the paper type information from the image forming apparatus PR side. If it is special paper, if the leading edge stopper 71 and / or the main jogger 210 are removed from the aligned state, the uppermost paper moves as described above, so that the subroutine moves to the special paper control subroutine and the processing of the subroutine is executed. If it is plain paper (NO in step S104), the normal control subroutine for plain paper is executed (step S105), and the process ends.

<Special paper control and normal control example 1>
FIG. 9A is a flowchart showing a control procedure of a special paper control subroutine in the first embodiment, and FIG. 9B is a flowchart showing a control procedure of a normal control subroutine. In the special paper control subroutine that is determined to be the special paper setting in step S103 of FIG. 8, the leading edge stopper 71 and the main jogger 210 are also in the subroutine for the special paper control executed in step S104 even after the discharge of the final stacked paper is completed in step S102. A total of three aligning means are held at the sheet contact position (step S104-1). When the sub-jogger 310 is also used, there are a total of five aligning means, but it is desirable that at least one, preferably a total of three of the tip stopper 71 and the main jogger 210 abut to hold the sheet. .

  In this state, it is determined whether or not there is a lowering request from the user to the shift tray 102 (step S104-2). When the lowering request is output (step S104-2: YES), it is determined whether or not a certain time has passed (step S104-3). Since it takes 15 to 30 seconds for the coated paper to settle down as a fixed time, 30 seconds is used as the judgment value as the elapsed time from the final paper discharge (step S102) in FIG. If the fixed time has elapsed (step S104-3: YES), the tip stopper 71 and the main jogger 210 that have been in contact with the sheet are moved to the retracted position (step S104-4), and the tip stopper 71 and the main jog After completion of the movement of the jogger 210, the shift tray 102 starts to descend (step S104-5). When the lowering of the shift tray 102 is completed (step S104-6), printing is finished.

  On the other hand, if the fixed time has not elapsed in step S104-3, the shift tray 102 starts to descend (step S104-7), and after the shift tray 102 has been lowered (step S104-8), the leading end stopper is stopped. 71 and the main jogger 210 are moved to the retracted position (step S104-9), and printing is completed.

  In the normal control of FIG. 9B, if the special paper is not set in step S103, the front end stopper 71 and the main jogger 210 that are in contact with the sheet bundle are moved to the retracted position (step S105-1), and the user Is started (step S105-2), the shift tray 102 starts to be lowered (step S105-3), and when the shift tray 102 is lowered (step S105-4), the printing is finished. .

<Special paper control and normal control example 2>
FIG. 10 is a modification of FIG. 9, and is an example in which the lowering speed of the shift tray 102 in FIG. That is, when the fixed time has not elapsed in step S4-3, the shift tray 102 starts to descend at a lower speed (hereinafter the same) than in the case of normal control (step S104-7a), and after the shift tray has been lowered. (Step S104-8), the leading end stopper 71 and the main jogger 210 are moved to the retracted position (Step S104-9), and printing is completed. Other processes are the same as those in FIG.

  In addition, the normal control of FIG.10 (b) becomes the same control procedure as FIG.9 (b).

<Special paper control and normal control example 3>
FIG. 11 is a modified example of FIG. 9, FIG. 11 (a) changes a part of the processing procedure of FIG. 9 (a), and FIG. Is.

  In FIG. 11A, when it is determined in step S103 in FIG. 8 that the special paper is set, even after the completion of the discharge of the final stacked paper in step S2, the total three alignment means of the leading end stopper 71 and the main jogger 210 are the sheet. The contact position is held (step S104-1). As described with reference to FIG. 9, it is desirable that at least one of the alignment means, preferably a total of three of the tip stopper 71 and the main jogger 210 abut to hold the sheet.

  In this state, it is determined whether or not there is a first lowering request from the user with respect to the shift tray 102 (step S104-2a). When the first lowering request is output (step S104-2a: YES), a certain time has elapsed since the last sheet is discharged to the shift tray 102, as in the process of FIG. 9A. It is determined whether or not there is (step S104-3). In this case, 30 seconds is the determination value as a fixed time. If it is determined that a certain time has elapsed (step S104-3: YES), the tip stopper 71 and the main jogger 210 that have been in contact with the sheet are moved to the retracted position (step S104-4), and the tip stopper 71 is moved. After completion of the movement of the main jogger 210, the shift tray 102 starts to descend (step S104-5). When the lowering of the shift tray 102 is completed (step S104-6), printing is finished.

  On the other hand, if the predetermined time has not elapsed in step S104-3, the lowering of the shift tray 102 is started at a low speed (step S104-7a), and it is confirmed whether or not the lowering of the shift tray 102 is completed (step S104-3). S104-8a). If the lowering is completed, the tip stopper 71 and the main jogger 210 are moved to the retracted position (step S104-9), and printing is completed.

  If the lowering of the shift tray 102 is not completed in step S104-8a, it is determined whether or not a second lowering request is issued from the user (step S104-3b). If the second lowering request is not issued in this determination, the process returns to step S104-8a and waits for the lowering of the shift tray 102 to be completed.

  If it is determined in step S104-3b that a second lowering request has been issued, the lowering speed of the shift tray 102 is changed to lower at a speed faster than the speed in step S104-7a (step S104-10). When the lowering of the shift tray 102 is completed (step S104-11), the leading end stopper 71 and the main jogger 210 are moved to the retracted position (step S104-12), and printing is completed.

  Further, in FIG. 11B, the judgment of the lowering request in step S105-2 in FIG. 9B is different only in whether or not the first lowering request is made, and if the special paper is not set in step S103. Then, the front end stopper 71 and the main jogger 210 that are in contact with the sheet bundle are moved to the retracted position (step S105-1), and when the user makes a first lowering request (step S105-2a), the shift tray 102 is moved. Is started (step S105-3), and when the lowering of the shift tray 102 is completed (step S105-4), printing ends.

  FIG. 12 is a flowchart illustrating a control procedure of sheet misalignment suppression control according to the second embodiment. In the figure, the stacker 100 discharges a sheet to the shift tray 102 which is a stacking unit in the shift mode setting (step S201). In step S201, with respect to the shift operation described in the second shift mechanism, the front end is aligned by the third front end alignment mechanism, and the shift tray 102 is aligned by the main jogger 210 described in the fourth main jogger mechanism. The action is executed. Although not described in detail here, the sub jogger 310 operates when the use condition of the sub jogger 310 is met.

  When the shift operation and the alignment operation are executed according to the set shift mode and the final sheet is discharged onto the shift tray 102 (step S202), the leading end stopper 71 and the main jogger 210 are moved to the retracted position (step S203). ) Waits for a lowering request from the user (step S204), and when a lowering request is issued from the user (step S204: YES), it is determined whether or not a certain time has passed since the completion of paper discharge in step S202. (Step S205). This fixed time is determined using 30 seconds as a determination value, as in step S104-3 in FIG. If it is determined that a certain time has elapsed, the shift tray 102 starts to descend (step S206). When the descending is completed (step S207), printing is finished.

  On the other hand, if the predetermined time has not elapsed in step S205 (step S205: NO), it is determined whether or not the sheet setting of the final sheet conveyed from the image forming apparatus PR is a special sheet (step S208). If it is not special paper, the process proceeds to step S206, and if it is special paper (step S208: YES), the leading end stopper 71 and the main jogger 210 that have been retracted in step S203 are moved to the contact position with the sheet, and the sheet bundle is moved. Contact with PB (step S209). As described above, the alignment member is in contact with the sheet bundle at three points here, but it is necessary to make contact with at least one point.

  Next, the shift tray 102 starts to descend (step S211). After the completion of the descending (step S211), the front end stopper 71 and the main jogger 210 that have been in contact with the sheet bundle PB are retracted (step S212), and printing is completed. It becomes.

  When the processing procedure shown in FIG. 12 is executed, the lowering speed of the shift tray 102 may be lowered as shown in step S210a of FIG. As a result, the sheets of the sheet bundle PB can be moved at a low speed with respect to the leading end stopper 71 and the main jogger 210 that have been in contact with the sheet bundle PB in step S209, and accordingly, the possibility of deviation or deviation is suppressed. be able to.

  FIG. 14 is a flowchart illustrating a control procedure of sheet deviation suppression control according to the third embodiment. In FIG. 14, the same reference numerals are assigned to the same processes as those in the flowchart of FIG. 12, and different points will be described mainly.

  Processing is started in the same manner as in the flowchart of FIG. 12, the tip stopper 71 and the main jogger 210 are moved to the retracted position in step S203, and the user waits for a first lowering request (step S204a). When the first descent request is issued (step S204: YES), it is determined whether or not a certain time has elapsed since the completion of the paper discharge in step S202 (step S205). This fixed time is determined using 30 seconds as a determination value, as in step S104-3 in FIG. If it is determined that a certain time has elapsed, the shift tray 102 starts to descend (step S206). When the descending is completed (step S207), printing is finished.

  If the predetermined time has not elapsed in step S205, it is determined whether or not a second descending request has been issued (step S204b). If a second descending request has been issued (step S204b: YES), step S206 is determined. Subsequent processing is executed, and if it is not output, it is determined whether special paper is set for the final paper (step S208). If the special paper is not set, the processing after step S206 is executed as plain paper. If the special paper is set (step S208: YES), the leading end stopper 71 and the main jogger 210 that have been retracted in step S203 are displayed. Is moved to the contact position with the sheet and is brought into contact with the sheet bundle PB (step S209). Next, the lowering of the shift tray 102 is started at a low speed (step S210a), and it is confirmed whether a second lowering request is made by the user before the shift tray 102 completes lowering (step S204c). If not, the process returns to step S211a to repeat a loop for confirming whether or not the descent is completed. When the lowering of the shift tray 102 is completed (step S211a: YES), the leading end stopper 71 and the main jogger 210 are retracted to a position where they do not interfere with the sheet bundle PB (step S212), and printing is completed.

  On the other hand, when the second lowering request is made by the user before the completion of the lowering (step S204c: YES), the lowering speed of the shift tray 102 is changed. Here, since the lowering speed is set at step S210a, the lowering speed at step S206 is changed. Returning to step S213, when the lowering of the shift tray 102 is completed (step S214), the leading end stopper 71 and the main jogger 210 are retracted to a position where they do not interfere with the sheet bundle PB (step S215), and printing is completed.

As described above, according to the present embodiment,
1) When the last sheet of the sheet is discharged to the shift tray 102 and the sheet stacking is completed, if the sheet is a special sheet, the main jogger 210 and / or the leading end stopper 71 are placed on the sheet on the shift tray 102. Since the lowering of the sheet stacking unit is started in a state of being in contact with the sheet, occurrence of sheet misalignment can be suppressed.
2) If a certain period of time has passed before the user instructs the start of lowering of the shift tray 102, the occurrence of sheet misalignment can be suppressed by simply retracting the main jogger 210 and / or the leading end stopper 71. Accordingly, it is possible to suppress the consumption of extra power.
3) If the contact of the main jogger 210 and / or the front end stopper 71 with the sheet is continued from the time when the sheet stacking is completed, the main jogger 210 and / or the front end stopper 71 are once separated from the sheet and again reach the contact position. It is possible to eliminate the time required for the extra operation before the operation and the influence on the sheet when moving to the contact position again.
4) By slowing down the shift tray 102, the time during which the main jogger 210 and / or the front end stopper 71 suppresses the movement of the sheet can be extended.
5) Since the control of the main jogger 210 and / or the front end stopper 71 or the special paper of the shift tray 102 is stopped according to the user's request, the user can arbitrarily select the waiting time or the good sheet alignment. Can do.

  It should be noted that the present invention is not limited to this embodiment, and various modifications are possible, and all technical matters included in the technical idea of the invention described in the scope of claims are the subject of the present invention. .

JP 2004-059882 A

71 Stopper 100 Stacker 102 Shift tray 111 Sheet conveying roller 113 Followed roller 114 Inlet roller 210 Main jogger 310 Sub jogger

Claims (8)

A sheet stacking device including a sheet stacking unit that stacks a sheet conveyed by the sheet conveying unit on a tray that can be raised and lowered,
Main scanning alignment means for aligning the main scanning direction of the sheet;
Sub-scanning alignment means for aligning the sub-scanning direction of the sheet;
Control means for controlling the ascending / descending operation of the main scanning alignment means, the sub-scanning alignment means, and the sheet stacking means;
Have
When the last sheet of the sheet is discharged to the sheet stacking unit and the sheet stacking is completed, and the sheet stacked on the sheet stacking unit is a special sheet, the control unit is configured to perform the main scanning. A sheet stacking apparatus, wherein the sheet stacking unit starts to descend while at least one of the aligning unit and the sub-scanning aligning unit is in contact with a sheet on the sheet stacking unit. The sheet stacking apparatus according to claim 1,
Operating means for instructing the start of lowering of the sheet stacking means,
The control unit, after detecting a descent start signal based on an instruction from the operation unit, brings the alignment unit into contact with the sheet before starting the descent of the sheet stacking unit. The sheet stacking apparatus according to claim 1,
The sheet stacking apparatus, wherein the control unit continues the contact of the aligning unit with the sheet from the time when the sheet stacking is completed. The sheet stacking apparatus according to any one of claims 1 to 3,
The sheet stacking apparatus according to claim 1, wherein the control unit lowers the lowering speed of the stacking unit for a certain time from the start of the lowering with respect to the normal operation. The sheet stacking apparatus according to claim 4,
An operation means for the user to instruct the lowering of the sheet stacking means;
When a signal requesting lowering of the sheet stacking unit is continuously sent from the operation unit to the control unit, the control unit cancels the control of the alignment unit and the sheet stacking unit with respect to the special paper. Characteristic sheet stacking device.   An image forming apparatus comprising the sheet stacking apparatus according to claim 1. The image forming apparatus according to claim 6, wherein
An operation unit is provided on the image forming apparatus main body side,
An image forming apparatus, wherein an operation input to the sheet stacking apparatus is possible from the image forming apparatus main body side. A sheet stacking method of stacking a sheet transported by a sheet transport unit on a sheet stacking unit capable of moving up and down,
Main scanning alignment means for aligning the main scanning direction of the sheet;
Sub-scanning alignment means for aligning the sub-scanning direction of the sheet;
With
When the last sheet of the sheet is discharged to the sheet stacking unit and the sheet stacking is completed, and the sheet stacked on the sheet stacking unit is a special sheet, the main scanning alignment unit and the A sheet stacking method, wherein the sheet stacking unit starts to descend while at least one of the sub-scanning alignment units is in contact with a sheet on the sheet stacking unit.

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