JP2013139303A - Post processing device of image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a post processing device of an image forming apparatus, the device capable of correcting displacement of an alignment plate to improve alignment and achieve cost reduction, without providing an alignment plate detection sensor different in each sheet size.SOLUTION: A post processing device includes: determining a sheet arrangement position aligned by pushing a sheet using alignment plates 21A, 21B according to the size of the sheet, and an alignment retraction position retracted by the alignment plate until the following sheet is delivered after the sheet is arranged; and moving alignment plate detection means 26A, 26B to the sheet arrangement position and alignment retracted position via a moving means 30 for the detection means.

Description

  The present invention relates to a post-processing apparatus for an image forming apparatus that performs post-processing such as stapling on a plurality of sheets stored in a sheet storage unit.

  Generally, in the post-processing apparatus of the image forming apparatus as described above, the alignment plates (a pair of left and right) are provided on both sides in the sheet width direction of a plurality of sheets that have been printed and discharged and stored in the processing tray unit, These alignment plates are respectively connected to a belt driven by a motor, and both alignment plates are moved inward in the paper width direction, thereby pressing the paper from the width direction and aligning the edges of the paper before post-processing. I am doing so.

  Specifically, as shown schematically in FIG. 18, the driving pulleys 103A and 103B are respectively attached to the rotation shafts of the pair of stepping motors 102A and 102B provided corresponding to the pair of left and right alignment plates 101A and 101B, respectively. The belt 105A is hung between the left driving pulley 103A and the corresponding driven pulley 104A, while the belt 105B is hung between the right driving pulley 103B and the corresponding driven pulley 104B. The left and right alignment plates 101A and 101B are connected to the left and right belts 105A and 105B, respectively.

  That is, when the driving pulleys 103A and 103B are rotated by the stepping motors 102A and 102B, the left and right alignment plates move inward with respect to the left and right belts 105A and 105B, and the paper is moved in the width direction at the paper alignment position. The paper edges are aligned and aligned.

  By the way, when there are a large number of sheets to be aligned, the alignment plates 101A and 1B cannot accurately reach (cannot be pushed into) the sheet alignment position due to the strength of the sheet, thereby causing the stepping motor 102A to step out. There is.

  When the stepping motor 102A is stepped out, the alignment plates 1A and 1B are misaligned, so that the subsequent sheet alignment positions are also deviated and the alignment function is degraded.

  Conventionally, in order to correct the misalignment of the alignment plate, an appropriate sheet is adjusted during the alignment operation by controlling the alignment plate to return to the home position every time a predetermined number of sheets are discharged. A technique is known that corrects the shift of the alignment plate that could not reach the alignment position so that it can reach the proper sheet alignment position. Also, every time the alignment operation is performed a predetermined number of times, the correct sheet alignment position cannot be reached during the alignment operation by increasing the number of driving pulses of the stepping motor when moving from the alignment retract position to the sheet alignment position by the alignment operation. There has been proposed a technique that allows the alignment plate to reach an appropriate sheet alignment position (see, for example, Patent Document 1).

JP-A-2005-194105

  However, as for the technology to correct the deviation by returning the alignment plate to the home position, if the alignment plate is displaced due to the stepping motor stepping out, and the alignment plate cannot reach the proper alignment retract position or paper alignment position, the stepping From the step-out of the motor until the misalignment of the alignment plate is corrected, the alignment is also degraded.

  In order to solve such a problem, for example, it may be possible to provide a sensor for detecting that the alignment plate has reached an appropriate alignment retract position or sheet alignment position. Different sensors are required for each paper size at the paper alignment position, which may increase the number of parts and increase the cost significantly.

  On the other hand, with respect to the method of increasing the number of stepping motor drive pulses every time the alignment operation is performed, the alignment plate moves from the alignment retract position to the paper alignment position when the alignment operation is performed a predetermined number of times even when the alignment plate is not displaced. This increases the number of driving pulses of the stepping motor.

  Increasing the number of pulses when aligning weak sheets or a small number of sheets will cause the alignment plate to move to the inside of the paper width, causing the sheet to bend and the alignment plate to move to the alignment retracted position. When returning to the position, the bundle of sheets is broken, and the consistency is also lowered.

  The present invention has been made in view of the above circumstances, and can improve alignment by correcting misalignment of the alignment plate without providing a different alignment plate detection sensor for each paper size. An object of the present invention is to provide a post-processing apparatus that can reduce the cost.

The above problem is solved by the following means.
(1) a sheet storage means for storing a plurality of printed sheets, and a pair of alignment plates that align and align the sheets by pressing the plurality of sheets stored in the sheet storage means from both sides in the width direction; Alignment plate moving means for moving the alignment plate in the paper width direction, alignment plate detection means for detecting the alignment plate at a predetermined position and positioning the alignment plate, and moving the alignment plate detection means in the paper width direction The detecting means moving means, the paper aligning position where the paper is pushed by the aligning plate in accordance with the size of the paper, and the aligning plate is retracted until the next paper is discharged after aligning the paper An image forming apparatus comprising: a control unit that determines an alignment retreat position and moves the alignment plate detection unit to the paper alignment position and the alignment retraction position via the detection unit moving unit Post-processing equipment.
(2) The post-processing apparatus according to item 1, wherein the control unit moves the alignment plate to a home position at a timing when the alignment plate needs to be initially aligned.
(3) The control unit measures the timing at which the alignment plate detection unit detects the position of the alignment plate during the alignment operation with respect to the sheet, and calculates the alignment plate misalignment amount from the measurement result. 3. The post-processing device according to item 1 or 2, which corrects the position of the plate.
(4) The control means measures the timing of detecting the position of the alignment plate by the alignment plate detection means during the alignment operation for the paper, and if there is a misalignment of the alignment plate from the measurement result, one sheet of paper 3. The post-processing device according to claim 1 or 2, wherein control is performed to increase the number of times of alignment for the image forming device.
(5) When the alignment plate moves from the alignment retract position to the paper alignment position, the control unit moves the alignment plate detection unit to the paper alignment position, and in that state, moves the alignment plate to the paper alignment position. After alignment, with the alignment plate moved from the paper alignment position to the alignment retracted position, the alignment plate detection means is moved from the paper alignment position to the alignment plate position to shift the alignment plate stop position. 5. The post-processing device according to any one of items 1 to 4, wherein the amount is detected and corrected.
(6) The post-processing device according to item 4 or 5, wherein the control unit thins out the number of times of alignment when the amount of deviation of the alignment plate is smaller than a reference value.
(7) A single motor is used as a moving drive source for the pair of alignment plates that move in the paper width direction via the alignment plate moving means, and the control means uses the detection means moving means for one alignment. 7. The post-processing apparatus according to any one of items 1 to 6, wherein the plate detection unit is disposed at the sheet alignment position, and the other alignment plate detection unit is disposed at the alignment retreat position.
(8) When performing stronger alignment with the sheet, the control unit moves the alignment plate detection unit to the inside of the sheet width and moves the alignment plate until the alignment plate detection unit detects the alignment plate. The post-processing device according to any one of items 1 to 7, wherein the post-processing device is moved.
(9) In the case where the control unit aligns the sheet by moving the sheet to one side in the sheet width direction, the other alignment plate is not moved from the home position without moving the alignment plate detection unit that is closer to the sheet alignment position. 2. The post-processing device according to item 1, wherein only the detection means is moved.
(10) The post-processing apparatus according to any one of items 1 to 9, wherein the control unit controls the alignment plate detection unit not to move from the home position when aligning a wide sheet.

  According to the invention of the preceding paragraph (1), the sheet aligning position where the sheet is pushed by the aligning plate in accordance with the sheet size and the aligning plate is retracted until the next sheet is discharged after aligning the sheet. And the alignment plate detecting means moves to the paper alignment position and the alignment retract position via the detecting means moving means, and the alignment plate detecting means detects the alignment plate, Positioning of the alignment plate can be performed reliably, and thus proper alignment operation can be performed. Moreover, since the alignment plate detection means moves via the detection means moving means, it is possible to cope with different paper sizes, and it is necessary to introduce a different alignment plate detection sensor for each paper size. On the other hand, the number of parts is reduced, and the production cost can be greatly reduced.

  According to the invention of the preceding item (2), the initial alignment of the alignment plate is performed when the power is turned on and when the cover is opened and closed, and the subsequent alignment operation can be appropriately performed.

  According to the invention of (3), since the shift amount is calculated from the detected position of the alignment plate measured during the alignment operation of the sheet and the position of the alignment plate is corrected, the alignment with the sheet is improved.

  According to the invention of the preceding item (4), if there is a misalignment amount of the alignment plate during the alignment operation of the sheet, the number of alignments for one sheet can be increased, so that the alignment with the sheet is improved.

  According to the invention of the preceding item (5), the alignment plate detection means at the alignment retreat position of the alignment plate detects and corrects the alignment plate displacement.

  According to the invention of the preceding item (6), since the number of times of matching can be thinned out, it is possible to achieve noise reduction and power saving of the matching operation.

  According to the invention of the preceding item (7), for example, a rack and pinion mechanism is employed, and proper alignment operation can be performed with a simple configuration using one motor as a drive source.

  According to the invention of the preceding item (8), when performing stronger alignment with the paper, the alignment plate detecting means is moved to the inner side than the paper width, so that even when the paper is stiff, the paper is properly aligned. Can be obtained.

  According to the invention of the preceding item (9), it is possible to align the sheets only by moving one alignment plate during the alignment operation when the shift function is used.

  According to the invention of the preceding item (10), with wide paper, it is possible to align the paper without moving the alignment plate detecting means from the home position.

1 is a schematic cross-sectional view showing a post-processing apparatus of an image forming apparatus according to an embodiment of the present invention. FIG. 6 is a perspective view schematically illustrating a configuration of a sheet alignment unit. FIG. 6 is an operation explanatory diagram of the sheet aligning unit. It is a flowchart which shows the flow of the initial control process which returns a matching plate and a matching plate sensor to a home position. 6 is a flowchart showing a flow of processing of sheet alignment operation. It is a table | surface which shows the distance from the home position of a matching plate to a retracted position, and the required number of pulses of a motor for every paper size. 10 is a flowchart showing a flow of processing for correcting the amount of misalignment of the alignment plate at the sheet alignment position and the retracted position. It is a flowchart which shows the flow of a process in the case of increasing / decreasing the number of times of alignment according to the positional offset amount of an alignment plate. It is a perspective view which shows the principal part structural example in the case of using one motor as a drive source of a matching plate. FIG. 10 is a schematic operation explanatory diagram of the configuration example of FIG. 9. 10 is a flowchart showing a flow of a paper alignment operation process in the configuration example of FIG. 9. 10 is a table showing the distance from the home position to the retracted position of the alignment plate and the required number of pulses for each sheet size in the configuration example of FIG. 9. It is a flowchart which shows the flow of a process of the alignment operation | movement at the time of moving an alignment board sensor to the inner side from a paper width | variety and strengthening alignment force. 6 is a flowchart illustrating a flow of processing for aligning sheets using a shift function. It is a table | surface which shows the distance to the alignment evacuation position for every paper size at the time of use of a shift function, and required pulse number. It is a flowchart which shows the flow of a process of the alignment operation in the case of a wide paper. 10 is a table showing the number of alignment pulses for aligning a large size sheet for each sheet size. It is a perspective view which shows the outline | summary of the conventional paper alignment mechanism.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic sectional view showing a post-processing apparatus of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view schematically showing a configuration of a sheet aligning unit, and FIG. 3 is an operation of the sheet aligning unit. It is explanatory drawing. In the following, the operation overview of the post-processing apparatus will be described.

  When the printed sheet M (shown in FIG. 3) is discharged from the image forming apparatus 1, the inlet sensor 5 on the upstream side of the sheet conveyance path 4 in the post-processing apparatus 2 is turned on, and the sheet M is conveyed to the sheet. It is transported by a plurality of pairs of transport rollers 3 in the path 4.

  A punch 6 is provided on the paper conveyance path 4, and when punching the fed paper M, the paper M is conveyed after a predetermined time has elapsed since the entrance sensor 5 was turned on. While being stopped on the path 3, the punching operation by the punch 6 is performed on the paper M. The paper M after the end of the punching operation is transported again, and then the transport sensor 7 is turned on.

  When the sheet M is output as it is to the elevator tray 9 projecting outward from the rear portion of the post-processing apparatus 1 (straight discharge), the upper paddle 10 to be pressed / separated is pressed in a state of being pressed. If it is rotated, the paper M is discharged straight to the elevator tray 9.

  When stapling is performed on the paper M, if the upper paddle 10 is separated, it is not discharged to the elevator tray 9 and the rear end of the paper M is placed on the receiving belt 11 as the paper storing means. Fall. Before the paper M falls on the storage belt 11, the storage belt 11 and the storage upper paddle 10 are rotated in a direction in which the paper M returns toward the stapler 12. The rotation of the storage belt 11 is stopped after a predetermined time has elapsed after the trailing edge of the paper M turns on the processing tray sensor 13.

  If the upper paper paddle 10 is separated and the upper paper paddle 10 is rotated while the next paper M is separated, the dropped paper M overlaps while sliding on the first paper.

  When the printed sheets M are stored in a stack on the storage belt 11 in this way, the sheet ends are pressed and aligned by the pair of left and right alignment plates 21A and 21B in the sheet alignment section 50 (shown in FIG. 2). Matched to the state. Thereafter, the sheet bundle is bound by operating the stapler 12 at a desired position.

  When the stapling process for the paper M is completed, the storage belt 11 is rotated in the discharge direction, the upper storage paddle 10 is pressed and rotated in the discharge direction, and the stapled paper bundle is discharged to the elevator tray 9.

  The post-processing device 2 further includes a control unit 14 that comprehensively controls the entire post-processing device 2 such as controlling the paper aligning unit 50 in accordance with the paper information from the paper size detecting unit 15.

  Specifically, the control unit 14 determines the paper alignment position, and moves the alignment plates 21A and 21B to the paper alignment position via the alignment plate moving mechanism 20 as shown in FIG. Alignment is performed by pressing from both sides in the direction, and an alignment retreat position for retracting the alignment plates 21A and 21B until the next sheet M is discharged is determined, and the alignment plate 21A is set via the alignment plate moving mechanism 20. , 21B are moved to the alignment plate retracted position.

  Further, the control unit 14 performs control such as moving the alignment plates 21A and 21B to the home position in order to perform initial alignment of the alignment plates 21A and 21B when the power is turned on and when the cover is opened and closed.

  As shown in FIGS. 2 and 3, the sheet aligning unit 50 moves the aligning plate moving mechanism 20 and the aligning plate detecting means (referred to as an aligning plate sensor) provided in the aligning plate moving mechanism 20. The sensor movement mechanism 30 is provided.

  2 and 3, the alignment plate moving mechanism unit 20 includes a pair of stepping motors arranged in correspondence with the pair of alignment plates 21 </ b> A and 21 </ b> B in the width direction (a direction) of the sheet M, respectively. Between the motors 22A and 22B, the left and right driving pulleys 23A and 23B that are directly or indirectly driven by the rotational forces of the motors 22A and 22B, and the left driving pulley 23A and the corresponding driven pulley 24A. A belt 25A that is hung, and a belt 25B that is hung between a right driving pulley 23B and a corresponding driven pulley 24B are provided. Each of the belts 25A and 25B has a width of paper M. The base end (lower end) side of the pair of left and right alignment plates 21A and 21B aligned by pressing from the direction is connected.

  That is, by rotating the driving pulleys 23A and 23B by the pair of motors 22A and 22B, the alignment plates 21A and 21B are moved inward in the paper width direction via the left and right belts 25A and 25B, and at the paper alignment position. When the paper M is pressed from the width direction, the paper M is aligned and aligned. At this time, the output pulses of the motors 22A and 22B are 4000 pps.

  The sensor moving mechanism 30 is directly or indirectly driven by a pair of motors 32A and 32B provided corresponding to the pair of alignment plate sensors 26A and 26B, respectively, and the rotational forces of the motors 32A and 32B. Between the left and right driving pulleys 33A and 33B, the left driving pulley 33A and the corresponding driven pulley 34A, and the right driving pulley 33B and the corresponding driven pulley 34B. And a base end (lower end) side of the pair of alignment plate sensors 26A, 26B is connected to the belts 35A, 35B.

  That is, by rotating the driving pulleys 33A and 33B by the pair of motors 32A and 32B, the alignment plate sensors 26A and 26B can be moved in the sheet width direction via the left and right belts 35A and 35B.

  Each of the alignment plate sensors 26A and 26B is provided with two protruding pieces 26C and 26D that protrude horizontally toward the alignment plate moving mechanism 20 and are opposed to each other with an interval in the vertical direction. A light projecting element and a light receiving element (not shown) are attached to the opposing surfaces of the protrusions 26C and 26D of the alignment plate sensors 26A and 26B. In addition, one light-shielding protrusion 21C that protrudes horizontally toward the sensor moving mechanism 30 is provided on the surface of the alignment plate 21A, 21B on the sensor moving mechanism 30 side. Yes.

  Then, as the alignment plates 21A and 21B and / or alignment plate sensors 26A and 26B move, the light shielding protrusions 21C of the alignment plates 21A and 21B become two protrusions 26C of the alignment plate sensors 26A and 26B, 26D, the light projecting / receiving elements of the two projecting pieces 26C and 26D detect the light shielding projecting part 21C of the matching plates 21A and 21B, and based on this detection, as shown in FIG. The alignment position, the retraction position, the home position, etc. can be determined.

  In addition, the alignment plate moving mechanism 20 is detected by the light projecting / receiving elements of the two protrusions 26C and 26D of the alignment plate sensors 26A and 26B moved to the outermost position in the paper width direction. Light shielding members 27A and 27B having horizontal light shielding protrusions 27C are provided. Based on the detection of the light shielding members 27A and 27B by the respective alignment plate sensors 26A and 26B, the alignment plate sensors 26A and 26B can be positioned such as the home position.

  By the way, when the power is turned on and the cover is closed, the positions of the alignment plates 21A and 21B and the positions of the alignment plate sensors 26A and 26B cannot be specified. Therefore, it is necessary to return to the home position once before performing the alignment operation.

  FIG. 4 is a flowchart showing a flow of initial control processing for returning the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B to the home position.

  In FIG. 4, in step S1, the alignment plate sensors 26A and 26B are moved to the outside in the sheet width direction (in the direction away) while counting the number of pulses of the motors 32A and 32B. In step S2, the alignment plate sensors 26A and 26B move from the innermost position to the outermost position to determine whether or not the light shielding members 27A and 27B are detected (whether they are turned on). (YES in step S2), the process proceeds to step S4. If it is not ON (NO in step S2), it is predicted that the positions of the light shielding members 27A and 27B have not been reached, and the process proceeds to step S3.

  In step S3, the number of pulses required for the alignment plate sensors 26A and 26B to move from the innermost position to the outermost position and turn ON is 400, whereas the pulse counts of the alignment plate sensors 26A and 26B are It is determined whether or not 450 is exceeded (pulse count> 450).

  If pulse count> 450 (NO in step S3), the process returns to step S2. If pulse count> 450 (YES in step S3), an error is displayed on the operation panel in step S10, and then in step S11. Then, the movement of the alignment plates 21A and 21B is stopped.

  On the other hand, in step S4, since the alignment plate sensors 26A, 26B reach the positions of the light shielding members 27A, 27B and are turned on, the movement of the alignment plate sensors 26A, 26B is stopped. In step S5, the alignment plate sensor 26A. , 26B, for example, 25 pulses to the inside and stop at the home position.

  In step S6, since the alignment plates 21A and 21B are always positioned inside the alignment plate sensors 26A and 26B, the alignment plates 21A and 21B are first moved inward by 30 pulse sentences and stopped. In step S7, the alignment plates 21A and 21B are moved outward while counting the number of pulses of the alignment plates 21A and 21B.

  In step S8, it is determined whether or not the alignment plates 21A and 21B have reached the home position and the alignment plate sensors 26A and 26B are turned on, and the alignment plates 21A and 21B have not reached the home position and the alignment plate sensors 26A and 26B. If is not ON (NO in step S8), the process proceeds to step S9. If the alignment plates 21A and 21B reach the home position and the alignment plate sensors 26A and 26B are turned on (YES in step S8), the alignment plates 21A and 21B are stopped and then terminated in step S11.

  In step S9, it is determined whether or not the pulse count of the alignment plates 21A and 21B exceeds 450 (pulse count is> 450). If the pulse count is not> 450 (NO in step S9), the process proceeds to step S8. Return. If the pulse count is> 450 (YUE step S in step S9), in step S10, an error is displayed on the operation panel (not shown), the process proceeds to step S11, and the movement of the alignment plates 21A and 21B is stopped.

  Note that the movement amounts of the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B may be controlled not by the number of pulses of the motors 22A, 22B, 32A and 32B but by the distance and time.

  FIG. 5 is a flowchart showing a flow of processing for alignment of paper during printing.

  In FIG. 5, when printing is started, in step S21, the size in the width direction of the printing paper is determined from information set by the user on the operation panel or the printer driver, the alignment retreat position corresponding to the paper size is determined, The alignment plates 21A and 21B and the alignment sensors 26A and 26B are moved from the home position to the alignment retreat position inside a predetermined number of pulses. In this embodiment, as shown in the table of FIG. 6, the number of pulses for moving to the alignment retracted position is stored in advance for each size in the width direction, and the number of pulses is determined based on this table.

  In the table of FIG. 6, for example, when the paper M is A4 vertical size, the distance from the home position to the retracted position is 43 mm, and the number of pulses is 106.

  In step S22, it is determined whether or not the rear end of the sheet M has passed through the inlet sensor 5 of the post-processing device 2 and the inlet sensor 5 has been turned off, and the rear end of the sheet M has passed through the inlet sensor 5 and is turned off. If it is YES (YES in step S22), the process proceeds to step S23, and if the trailing edge of the sheet M does not pass through the inlet sensor 5 and is not OFF (NO in step S22), it waits for passing.

  In step S23, it is determined whether or not a time (for example, 500 mS) until the paper M falls on the storage belt (also referred to as a processing tray) 11 and is stored has passed, and if 500 mS has not passed (in step S23). NO), wait for the passage of time. If 500 mS has elapsed (YES in step S23), the alignment operation for the paper M is performed in step S24. That is, the alignment plates 21A and 21B are moved inward in the paper width direction by the number of alignment pulses (for example, 80 pulses) and stopped at the paper alignment position.

  In step S25, it is determined whether or not there is a next sheet M. If there is no next sheet M (NO in step S25), the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are moved to the home position in step S31. After moving to, the process ends. If there is a next sheet M (YES in step S25), an opening operation after the alignment operation is performed in step S26. That is, the alignment plates 21A and 21B are moved outward in the paper width direction while counting the number of pulses of the motor.

  In step S27, it is determined whether or not the alignment plates 21A and 21B have reached the alignment retracted position and the alignment plate sensors 26A and 26B are turned on. If the alignment plate sensors 26A and 26B are turned on (YES in step S27), In step S28, the alignment plates 21A and 21B are stopped at the retracted position, and then the process returns to step S22 to proceed to processing of the next sheet M. If the alignment plate sensors 26A and 26B are not turned ON (NO in step S27), the process proceeds to step S29.

  In step S29, it is determined whether or not the pulse count of the alignment plates 21A and 21B has exceeded 100 pulses (pulse count number> 100 pulses). If pulse count number> 100 pulses is not satisfied (NO in step S29), step S27 is performed. Return to. If the pulse count number> 100 pulses (YES in step S29), it is determined that the alignment plate sensor 26A (26B) does not turn ON even if the pulse exceeds 100 pulses, and the alignment retract position cannot be reached. The alignment plates 21A and 21B are stopped, an error is displayed on the operation panel, and the process is terminated.

  Since the movement of the alignment plates 21A and 21B is controlled based on the detection result of the positions of the alignment plates 21A and 21B by the alignment plate sensors 26A and 26B movable in the sheet width direction as described above, the alignment plate 21A is provided for each alignment operation. , 21B is not returned to the home position, and the misalignment of the alignment plates 21A, 21B is corrected during the alignment operation every time, thereby improving the alignment.

  Furthermore, compared to the case where different alignment plate detection sensors 26A and 26B are introduced for each paper size, the number of parts is reduced and the cost is reduced.

  By the way, the alignment plates 21A and 21B may be misaligned, and the alignment plates 21A and 21B may not be sufficiently opened from the sheet alignment position to the proper alignment retract position. Even if the sheet M is stored in the processing tray 11 in this state, the sheet M may get on the alignment plates 21A and 21B, and the alignment may not be performed properly.

  In order to solve this, it is necessary to return the alignment plates 21A and 21B to the proper alignment retracted position and drop the sheet M on the alignment plate before performing the alignment operation. In order to detect that the alignment plates 21A and 21B have reached the proper alignment retract position from the sheet alignment position, the alignment plate sensors 26A and 26B must be disposed at the alignment retract position.

  In addition, a large number of sheets M may be stacked on the processing tray 11, and the alignment plates 21A and 21B may not be able to reach the proper sheet alignment position from the alignment retract position during the alignment operation. In order to detect whether the alignment plates 21A and 21B have reached the proper paper alignment position, it is necessary to arrange the alignment plate sensors 26A and 26B at the paper alignment position.

  Therefore, in order to detect that the alignment plates 21A and 21B have reached the proper alignment retreat position and the proper paper alignment position, the alignment plate sensors 26A and 26B are moved between the alignment retraction position and the paper alignment position. Control to change.

  FIG. 7 is a flowchart showing the flow of processing for correcting the misalignment between the alignment position of the alignment plates 21A and 21B and the retracted position.

  In FIG. 7, in step S41, as in step S21 of FIG. 5, the alignment plates 21A and 21B and the alignment sensors 26A and 26B are moved inward by a predetermined number of pulses according to the size in the width direction of the sheet M. Stop at the retracted position. In step S42, the alignment plate sensors 26A and 26B are moved inward by the number of alignment pulses (for example, 80 pulses) and stopped at the sheet alignment position.

  In step S43, it is determined whether or not the trailing edge of the sheet M has passed through the inlet sensor 5 and turned off. If the trailing edge of the sheet has not passed through the inlet sensor 5 and is not turned off (NO in step S43), Wait for it to pass. If the trailing edge of the sheet M passes the entrance sensor 5 and is turned OFF (YES in step S43), the process proceeds to step S44.

  In step S44, it is determined whether or not a time (for example, 500 mS) until the paper M falls and is stored in the processing tray 11 has elapsed. If 500 mS has not elapsed (NO in step S44), the time elapses. wait. If 500 mS has elapsed (YES in step S44), the alignment operation for the paper M is performed in step S45. That is, the number of pulses of the alignment plates 21A and 21B is counted and moved inward in the paper width direction, and the process proceeds to step S46.

  In step S46, when the alignment plates 21A and 21B are moved inward, it is determined whether or not the alignment plate sensors 26A and 26B are ON. If the alignment plate sensors 26A and 26B are ON (YES in step S46), step S47 is performed. Then, the movement of the alignment plates 21A and 21B is stopped, and the process proceeds to step S48. If the alignment plate sensors 26A and 26B are not turned ON (NO in step S46), it is determined in step S55 whether the pulse count number exceeds 100 (pulse count number> 100). If the pulse count is not> 100 (NO in step S55), the process returns to step S46. If the pulse count> 100 (YES in step S55), the process proceeds to step S57, the movement of the alignment plate sensors 26A and 26B is stopped, an error is displayed on the operation panel, and the process is terminated.

  In step S48, in order to open the alignment plates 21A and 21B, the alignment plates 21A and 21B are moved outward by the number of alignment pulses (80 pulses) and stopped at the alignment retract position. Thereafter, in step S49, the alignment sensors 26A and 26B are moved outward while counting the number of pulses of the alignment sensors 26A and 26B.

  In step S50, it is determined whether or not the matching plate sensors 26A and 26B are turned on. If the matching plate sensors 26A and 26B are turned on (YES in step S50), the movement of the matching plate sensors 26A and 26B is stopped in step S51. Then, the process proceeds to step S52. If the alignment plate sensors 26A and 26B are not turned ON (NO in step S50), it is determined in step S56 whether the pulse count number exceeds 100 (pulse count number> 100).

  If the pulse count is not greater than 100 (NO in step S56), the process returns to step S50. If the pulse count> 100 (YES in step S56), in step S57, the movement of the alignment plate sensors 26A, 26B is stopped, an error is displayed, and the process is terminated.

  In step S52, it is determined whether or not there is a next sheet M. If there is no next sheet M (NO in step S52), the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are moved to the home position in step S58. After moving to, the process ends. If there is the next sheet M (YES in step S52), in step S53, the alignment plate displacement amount P1 is obtained by the equation P1 = pulse count−alignment pulse number.

  In step S54, the alignment plate sensors 26A, 26B are moved inward by the number of pulses obtained by adding P1 to the number of alignment pulses, stopped at the paper alignment position, and then the process returns to step S43.

  By such processing, the number of pulses when moving from the alignment retreat position to the paper alignment position is increased or decreased, and the alignment plate sensors 26A and 26B are moved to positions where the paper M is properly aligned by the alignment plates 21A and 21B. it can.

  FIG. 8 is a flowchart showing the flow of processing when the number of alignments is increased or decreased in accordance with the displacement amount P1 of the alignment plates 21A and 21B.

  In FIG. 8, in step S61, if the amount of deviation between the alignment plates 21A and 21B is 0 to 2 pulses, the alignment operation is thinned out (the number of thinnings ← 1), and the alignment operation is performed once on two sheets of paper. . In step S62, it is determined whether the deviation amount is 0 to 2 pulses or 3 pulses or more (deviation amount ≧ 3). If the deviation amount is 0 to 2 pulses, the process proceeds to step S63, and the deviation amount is 3 pulses or more. If (deviation amount ≧ 3), the process proceeds to step S67.

  In step S63, it is determined whether the thinning number is less than 5 or 5. If the thinning number is less than 5, in step S64, the thinning number is incremented, and then the process proceeds to step S65. If the number of thinned sheets is 5, the process proceeds to step S65 as it is. That is, according to the value of the shift amount P, the number of thinned sheets can be reduced to once every three sheets, once every four sheets, and can be thinned out once to a maximum of five sheets.

  Next, in step S65, alignment is performed at a number corresponding to the number of thinned sheets, and then the process proceeds to step S66.

  On the other hand, if the deviation amount P is 3 pulses or more (deviation amount ≧ 3) in step S62, the alignment operation is thinned out in step S67 (the number of thinning out ← 1). If there is still a deviation amount, in step S68, It is judged whether the deviation amount is 3-5 pulses, 6-8 pulses, or 9 pulses or more (deviation amount ≧ 9). If the deviation amount is 3-5 pulses, the alignment is performed once in step S71. Then, the process proceeds to step S66. If the deviation amount is 6 to 8 pulses, the alignment is performed twice in step S70, and then the process proceeds to step S66. If the deviation amount is 9 pulses or more, in step S69, the operation speed of the alignment plate is decreased, and then alignment is performed twice in step S70 before proceeding to step S66.

  In step S66, it is determined whether or not there is a next sheet. If there is no next sheet (NO in step S66), the process is terminated. If there is a next sheet (YES in step S66), the process returns to step S62.

  Thus, by thinning out the number of times of matching, noise during matching operation and power consumption can be reduced. When the deviation amount is 3 pulses or more, the alignment operation is performed one by one, and when the deviation amount is 6 to 8 pulses, the number of alignments is set to 2 to improve the alignment. When the deviation amount is 9 pulses or more, the alignment can be improved by setting the number of alignments to 2 and further reducing the operation speed of the alignment plate.

  When the number of times of alignment is increased in this way, it is necessary to increase the paper feed interval in order to prevent the next sheet M from being stored before the end of alignment.

  FIG. 9 is a perspective view showing a configuration example of a main part when one motor is used as a drive source for the alignment plates 21A and 21B.

  In FIG. 9, the alignment plate moving mechanism 200 includes a single motor (stepping motor) 41, a pinion 42 that is rotationally driven directly or indirectly by the motor 41, and a longitudinal direction (left-right direction) parallel to each other. And a pair of front and rear racks 43 </ b> A and 43 </ b> B that mesh with the pinion 42.

  The lower ends of the alignment plates 21A and 21B are joined and fixed to the upper surfaces of the racks 43A and 43B via support members 44A and 44B, respectively. The two alignment plates 21A, 21B are moved in opposite directions in the left-right direction via the pinion 42 and the racks 43A, 43B.

  The support members 44A and 44B of the alignment plates 21A and 21B are respectively provided with horizontal shielding protrusions 44C, and the end of each shielding protrusion 44C opposite to the pinion 42 is the support member. It protrudes outward beyond the edges in the width direction of 44A and 44B.

  A sensor moving mechanism 30 having the same configuration as that shown in FIG. 2 is provided outside the racks 43A and 43B in parallel with the racks 43A and 43B.

  That is, as shown in FIG. 10, outside the racks 43A and 43B, the driving pulleys 33A and 33B that are directly or indirectly driven by the rotational forces of the motors 32A and 32B, the left driving pulley 33A, Belt 35A suspended between the corresponding driven pulley 34A and the belt 35B suspended between the right driving pulley 33B and the corresponding driven pulley 34B, and the like. The base end (lower end) side of the alignment plate sensors 26A and 26B is connected to 35A and 35B, respectively. Although not shown in the figure, a pair of light shielding members that are detected by the light projecting / receiving elements of the alignment plate sensors 26A and 26B moved to the outermost position in the paper width direction are also provided. By such shielding protrusions 44C of the alignment plates 21A and 21B, alignment plate sensors 26A and 26B, and light shielding members, the home position, the sheet alignment position, the retraction position, etc. of the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B Positioning is possible.

  FIG. 11 is a flowchart showing the flow of the alignment operation when the mechanism 200 of the pinion 42 and the racks 43A and 43B, which is the configuration example of FIG. 9, is used. It is assumed that the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are at the home position.

  In FIG. 11, when printing is started, in step S81, the size in the width direction of the printing paper is determined from information set by the user using the operation panel or the printer driver, the alignment retreat position corresponding to the paper size is determined, The alignment plates 21A and 21B and the alignment sensors 26A and 26B are moved from the home position to the alignment retreat position inside a predetermined number of pulses. In this embodiment, as shown in the table of FIG. 12, the number of pulses for moving to the alignment retreat position for each size in the width direction is stored in advance, and the number of pulses is determined based on this table.

  In the table of FIG. 12, for example, in the case of A4 vertical size, the distance from the home position to the retracted position is 43 mm, and the number of pulses is 86.

  In step S82, one alignment plate sensor 26A (26B) is moved to the alignment retract position, and the other alignment plate sensor 26B (26A) is moved to the paper alignment position. The number of motor pulses required for this movement uses the number of pulses shown in the table of FIG. 12 for movement to the alignment retract position, and the number of alignment pulses ( For example, the number of pulses obtained by adding 64 pulses) is used.

  In step S83, it is determined whether or not the rear end of the sheet M has passed through the inlet sensor 5 of the post-processing device 2 and the inlet sensor 5 has been turned off, and the rear end of the sheet M has passed through the inlet sensor 5 and is turned off. If YES in step S83, the process proceeds to step S84. If the trailing edge of the sheet M does not pass through the entrance sensor 5 and is not OFF (NO in step S83), the process waits for the passage.

  In step S84, it is determined whether or not a time (for example, 500 mS) until the paper M is dropped and stored in the processing tray 11 has elapsed. If 500 mS has not elapsed (NO in step S84), the time elapses. wait. If 500 mS has elapsed (YES in step S84), an alignment operation for the paper M is performed in step S85. That is, the alignment plates 21A and 21B are moved inward in the paper width direction while counting the number of pulses, and the process proceeds to step S86.

  In step S86, it is determined whether or not the alignment plates 21A and 21B have reached the paper alignment position and the internal alignment plate sensor 26B (26A) has been turned on. If the inner alignment plate sensor 26B (26A) is not turned ON (NO in step S86), in step S93, it is determined whether or not the pulse count of the alignment plates 21A and 21B has exceeded 80 pulses (pulse count number> 80 pulses). If it is determined that the pulse count number is not greater than 80 pulses (NO in step S93), the process returns to step S86. If the pulse count number is greater than 80 pulses (YES in step S93), it is determined that the alignment plate sensors 26A and 26B have not been turned ON even if the number exceeds 80 pulses, the paper alignment position has not been reached. The plates 21A and 21B are stopped, an error is displayed on the operation panel, and the process is terminated.

  If the inner alignment plate sensor 26B (26A) is turned on in step S86 (YES in step S86), the movement of the alignment plates 21A and 21B is stopped in step S87, and then the process proceeds to step S88.

  In step S88, the alignment plates 21A and 21B are opened. That is, the alignment plates 21A and 21B are moved outward while counting the number of pulses. Next, in step S89, it is determined whether or not the outer alignment plate sensor 26A (26B) is turned on. If the outer alignment plate sensor 26A (26B) is not turned on (NO in step S89), in step S94, It is determined whether or not the pulse counts of the alignment plates 21A and 21B have exceeded 80 pulses (pulse count number> 80 pulses). If the pulse count number> 80 pulses (NO in step S94), the process returns to step S89. If the pulse count number is greater than 80 pulses (YES in step S94), it is determined that the outer alignment plate sensor 26A (26B) does not turn ON even if it exceeds 80 pulses. Then, the alignment plates 21A and 21B are stopped, an error is displayed on the operation panel, and the process is terminated.

  If the outer alignment plate sensor 26B (26A) is turned on in step S89 (YES in step S89), the movement of the alignment plates 21A and 21B is stopped in step S90, and the process proceeds to step S91.

  In step S91, it is determined whether or not there is a next sheet M. If there is no next sheet M (NO in step S91), the alignment plates 21A and 21B and alignment plate sensors 26B and 26A are moved to the home position in step S92. Return to. If there is a next sheet M (YES in step S91), the process returns to step S83.

  By the way, when aligning a plurality of stiff sheets M, if the alignment plates 21A and 21B move only to the end positions of the sheets, alignment failure may occur due to the strength of the sheets M. In order to solve this problem, both alignment plate sensors 26A and 26B are moved slightly inward from the end of the paper to perform stronger alignment.

  FIG. 13 is a flowchart showing a flow of processing of an alignment operation for moving the alignment plate sensors 26A and 26B to the inside of the sheet width. It is assumed that the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are at the home position.

  In FIG. 13, first, in step S101, the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are moved inward by a predetermined number of pulses according to the size of the sheet width, and stopped at the alignment retract position. In step S102, the alignment plate sensors 26A and 26B are further moved to the paper alignment position on the inner side of 80 pulses and then stopped.

If the paper basis weight is greater than 90 g / m ^2, it is determined in step S103 whether or not the paper basis weight is greater than 90 g / m ^{2 in} order to perform stronger matching. If the paper basis weight is greater than 90 g / m ² (YES in step S103), in step S104, the alignment plate sensors 26A and 26B are further moved inward by 5 pulses and moved inward from the end in the paper width direction. After stopping, it progresses to step S105. If the paper basis weight is not greater than 90 g / m ² (NO in step S103), the process proceeds to step S105 as it is.

  In step S105, it is determined whether or not the trailing edge of the sheet M has passed through the inlet sensor 5 of the post-processing device 2 and turned off. If the trailing edge of the sheet M does not pass through the entrance sensor 5 and is not turned off (NO in step S105), it waits for passage. If the trailing edge of the sheet M passes the entrance sensor 5 and is turned off (YES in step S43), the process proceeds to step S106.

  In step S106, it is determined whether or not a time (for example, 500 mS) until the paper M is dropped and stored in the processing tray 11 has elapsed. If not (NO in step S106), the time elapses. If 500 mS has elapsed (YES in step S106), the alignment operation for the paper M is performed in step S107. That is, the alignment plates 21A and 21B are moved inward in the paper width direction while counting the number of pulses, and the process proceeds to step S108.

  In step S108, it is determined whether or not the alignment plates 21A and 21B have moved to the alignment plate sensors 26A and 26B and the sensors are turned on. If the alignment plate sensors 26A and 26B are turned ON (YES in step S108), the movement of the alignment plates 21A and 21B is stopped in step S109, and the alignment plates 21A and 21B are opened in step S110. That is, the matching plates 21A and 21B are moved outward by the number of matching plate pulses (85 pulses) while counting the number of pulses.

  In step S111, the pulse count is determined. In order to prevent the sheet bundle from collapsing due to the reaction of the deflection of the sheet M, when the number of pulses becomes 5, it is determined in step S114 that the alignment plates 21A and 21B have reached the end in the sheet width direction, and the alignment plates 21A and 21A 21B is stopped for 100 mS. Then, after resuming the movement, the process returns to step S111.

  When the number of pulses is 85, the movement of the alignment plates 21A and 21B is stopped in step S112, and then the process proceeds to step S113.

  If the alignment plate sensors 26A and 26B are not turned ON in step S108 (NO in step S108), it is determined in step S116 whether pulse count> 105, and if pulse count> 105 is not satisfied (NO in step S116). Return to step S108. If pulse count> 105 (YES in step S116), after the movement of the alignment plates 21A and 21B is stopped in step S117, the alignment plates 21A and 21B are moved by the number of alignment plate pulses (85 pulses) in step S118. It moves outside and stops, and it progresses to step S113.

  In step S113, the presence / absence of the next sheet M is determined. If there is the next sheet M (YES in step S113), the process proceeds to step S105. If there is no next sheet M (NO in step S113), in step S115, the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are moved to the home position, and the process is terminated.

  By the way, when using the shift function to align the sheet M toward one side in the sheet width direction, the alignment plate sensor 26A (26B) that is closer to the sheet alignment position is not moved from the home position, Only the alignment plate sensor 26B (26A) is moved for alignment.

  FIG. 14 is a flowchart showing the flow of processing for aligning sheets using such a shift function.

  In FIG. 14, in step S121, an alignment retreat position and a paper alignment position corresponding to the paper width size when the shift function is used are obtained. That is, on the side where the distance from the home position to the paper alignment position is short, the alignment retract position is set to the same position as the home position, and on the far side, the alignment retract position is set from the position shown in the table of FIG.

  In the table of FIG. 15, when the size in the width direction of the paper is, for example, A4 length, the distance is 86 mm and the required number of pulses is 213 pulses.

  In step S122, for example, one of the alignment plates 21A (21B) and the alignment plate sensor 26A (26B) are moved to the determined alignment plate retracted position and stopped.

  In step S123, it is determined whether or not the trailing edge of the sheet M has passed through the inlet sensor 5 on the processing tray 11 side and turned off. If the trailing edge of the sheet M has not passed through the inlet sensor 5 and is not turned off ( In step S1123, NO) and wait for passage. If the trailing edge of the sheet M passes through the entrance sensor 5 and is turned OFF (YES in step S123), the process proceeds to step S124.

  In step S124, it is determined whether or not a time (for example, 500 mS) until the paper M falls and is stored in the processing tray 11 has elapsed. If 500 mS has not elapsed (NO in step S124), the time elapses. wait. If 500 mS has elapsed (YES in step S124), an alignment operation for the paper M is performed in step S125. That is, while counting the number of pulses of the alignment plate 21A (21B) (80 pulses), the plate is moved inward in the paper width direction and stopped at the paper alignment position, and then the process proceeds to step S126.

  In step S126, it is determined whether or not there is a next sheet M. If there is a next sheet M (YES in step S126), the process proceeds to step S127. If there is no next sheet M (NO in step S126), In step S132, the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are moved to the home position, and then the process ends.

  In step S127, the opening operation after alignment is performed. That is, the alignment plate 21B (21A) is moved outward while counting the number of pulses. Next, in step S128, it is determined whether or not the alignment plate 21B (21A) has reached the alignment retracted position and the alignment plate sensor 26B (26A) is turned on. If the alignment plate sensor 26B (26A) is turned on (step S128). In step S129, the alignment plate 21B (21A) is stopped at the retracted position, and then the process returns to step S123 to process the next sheet. If the alignment plate sensor 26B (26A) is not ON (NO in step S128), the process proceeds to step S130.

  In step S130, it is determined whether or not the pulse count number of alignment plate 21B (21A)> 100 pulses. If pulse count number> 100 pulses is not satisfied (NO in step S130), the process returns to step S128. If the pulse count number is greater than 100 pulses (YES in step S130), it is determined that the alignment plate sensor 26B (26A) has not been turned on even after exceeding 100 pulses, so that the alignment retract position could not be reached, and alignment is performed in step S131. The board 21B (21A) is stopped, an error is displayed on the operation panel, and the process is terminated.

  By the way, since the sheet width is wide in the A3 size and the landscape A4 size, the alignment is performed by regarding the home position as the alignment retreat position without moving the alignment plate sensors 26A and 26B from the home position.

  FIG. 16 is a flowchart showing the flow of the alignment operation for a wide sheet.

  In FIG. 16, in step S <b> 141, it is determined whether or not the trailing edge of the sheet M has passed through the inlet sensor 5 on the processing tray 11 side and turned off. If not (NO in step S141), it waits for passage. If the trailing edge of the sheet M passes the entrance sensor 5 and is turned off (YES in step S41), the process proceeds to step S142.

  In step S142, it is determined whether or not a time (for example, 500 mS) until the sheet M falls and is stored in the processing tray 11 has elapsed. If not (NO in step S142), the time is awaited. If 500 mS has elapsed (YES in step S142), an alignment operation for paper M is performed in step S143. That is, while counting the number of pulses of the alignment plates 21A and 21B, the sheet is moved inward (78 pulses) in the paper width direction and stopped at the paper alignment position, and then the process proceeds to step S144.

  Note that when aligning a large sheet M, the number of alignment pulses is set from the table shown in FIG. In the table of FIG. 16, for example, when the sheet width size is A3, the number of alignment pulses is 78, and the distance from the home position to the sheet alignment position is 31.5 mm.

  In step S144, it is determined whether or not there is a next sheet M. If there is a next sheet M (YES in step S144), the process proceeds to step S145, and if there is no next sheet M (NO in step S144), In step S150, the alignment plates 21A and 21B and the alignment plate sensors 26A and 26B are moved to the home position, and then the process ends.

  In step S145, the opening operation after alignment is performed. That is, the alignment plates 21A and 21B are moved outward while counting the number of pulses. In step S146, it is determined whether or not the alignment plates 21A and 21B have reached the alignment retreat position and the alignment plate sensors 26A and 26B are turned on. If the alignment plate sensors 26A and 26B are turned ON (YES in step S146), in step S147, the alignment plates 21A and 21B are stopped at the retracted position, and the process returns to step S141. If the alignment plate sensors 26A and 26B are not turned ON (NO in step S146), the process proceeds to step S148.

  In step S148, it is determined whether or not the pulse count number of the alignment plates 21A and 21B> 100 pulses. If the pulse count number> 100 pulses is not satisfied (NO in step S148), the process returns to step S146. If the pulse count is greater than 100 pulses (YES in step S148), it is determined that the alignment plate sensors 26A and 26B have not been turned on even if the number exceeds 100 pulses, and the alignment retract position has not been reached. In step S149, the alignment is performed. The plates 21A and 21B are stopped, an error is displayed on the operation panel, and the process is terminated.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Post-processing apparatus 14 ... Control part 15 ... Paper size detection part 20,200 ... Alignment board moving mechanism part 21A, 21B ... Alignment board 26A, 26B ... Alignment plate sensor 30 ... Movement mechanism of alignment plate sensor 41 ... Motor 50 ... Paper alignment unit

Claims (10)

Paper storage means for storing a plurality of printed paper;
A pair of alignment plates for aligning and aligning the sheets by pressing a plurality of sheets stored in the sheet storage means from both sides in the width direction;
Alignment plate moving means for moving the alignment plate in the paper width direction;
Alignment plate detecting means for detecting the alignment plate at a predetermined position and positioning the alignment plate;
Moving means for detecting means for moving the alignment plate detecting means in the paper width direction;
According to the size of the paper, a paper alignment position where the paper is pushed and aligned by the alignment plate, and an alignment retreat position where the alignment plate retracts after the paper is aligned and before the next paper is discharged are determined. Control means for moving the alignment plate detection means to the paper alignment position and alignment retraction position via the detection means moving means;
A post-processing device comprising an image forming apparatus.   2. The post-processing apparatus according to claim 1, wherein the control unit moves the alignment plate to a home position at a timing when initial alignment of the alignment plate is necessary.   The control means measures the timing at which the position of the alignment plate is detected by the alignment plate detection means during the alignment operation with respect to the paper, calculates the amount of misalignment of the alignment plate from the measurement result, and calculates the position of the alignment plate. The post-processing device according to claim 1, wherein the post-processing device corrects the image.   The control means measures the timing at which the position of the alignment plate is detected by the alignment plate detection means during the alignment operation for the paper, and if there is a misalignment of the alignment plate from the measurement result, the number of times of alignment for one sheet The post-processing apparatus according to claim 1, wherein the post-processing apparatus performs control for increasing the image quality.   The control means moves the alignment plate detection means to the paper alignment position when the alignment plate moves from the alignment retract position to the paper alignment position, and moves the alignment plate to the paper alignment position in that state. After alignment, with the alignment plate moved from the paper alignment position to the alignment retracted position, the alignment plate detecting means is moved from the paper alignment position to the alignment plate position to detect the deviation amount of the alignment plate stop position. The post-processing apparatus according to claim 1, wherein the post-processing apparatus corrects the image by performing correction.   6. The post-processing apparatus according to claim 4, wherein the control unit thins out the number of times of alignment when the amount of deviation of the alignment plate is smaller than a reference value.   One motor is used as a driving source for moving the pair of alignment plates that move in the paper width direction via the alignment plate moving means, and the control means detects one alignment plate detection means via the detection means moving means. 7. The post-processing apparatus according to claim 1, wherein the second alignment plate detecting unit is disposed at the alignment retreat position, while the other alignment plate detecting unit is disposed at the alignment retreat position.   The control means moves the alignment plate detection means to the inside of the paper width when performing stronger alignment with the paper, and moves the alignment plate until the alignment plate detection means detects the alignment plate. Item 8. The post-processing device according to any one of Items 1 to 7.   In the case where the sheet is aligned with one side in the sheet width direction, the control unit does not move the alignment plate detection unit that is closer to the sheet alignment position from the home position, but only the other alignment plate detection unit. The post-processing apparatus according to claim 1, wherein the post-processing apparatus is configured to move the image forming apparatus.   The image processing apparatus according to claim 1, wherein the control unit controls the alignment plate detection unit not to move from a home position when aligning a wide sheet.

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