JP2009012897A - Post-processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily detect an aligning state, to effectively carry out aligning action in poor aligning to maintain the maximum productivity, and to keep good post-processing quality. <P>SOLUTION: The post-processing device comprises a stacker portion stacking paper on which an image is formed in preparation for post-processing, a moving amount detecting means detecting moving amount when moving toward a stacking position when a tip end of new paper carried to the stacker portion reaches a predetermined position of the stacker portion, and a control means obtaining a tip end position of the paper according to a detection result of the moving amount detecting means, enables closed loop control for feeding back the tip end position of the paper which is actually carried and aligned, and reduces man-hour for keeping quality. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a post-processing apparatus that performs post-processing such as stapling and punching on a sheet on which an image has been formed.

The paper on which the image has been formed in the image forming apparatus is subjected to post-processing such as stapling and punching in a post-processing apparatus as desired. The post-processing apparatus is installed in the image forming apparatus or connected to the outside of the image forming apparatus. The post-processing apparatus includes a stack unit on which new sheets are sequentially transported and stacked, and the sheets stacked on the stack unit are aligned in the horizontal and vertical directions by the aligning means so that the sheets are aligned. A matching operation is performed (see, for example, Patent Document 1). The aligning means is also devised so that the aligning operation is performed well by changing the timing of the aligning operation according to the amount of sheets to be stacked.
JP-A-8-26579

  However, in the post-processing apparatus as described above, as a technique for improving the sheet alignability of the stacker unit, a predictive control is performed, and the control is based on an open loop. Therefore, if there is a case where the matching is not sufficiently performed, this cannot be solved, and a matching failure cannot be detected during the operation of the apparatus. For this reason, when the printed matter is shipped while maintaining the quality, it is necessary to actually see and confirm the finished printed matter, and there is a problem that extra man-hours are generated.

  Note that paper misalignment in the stacker section is particularly likely to occur in the vertical direction. This is because when the paper is newly conveyed, if the paper is curled or the like, the leading edge of the paper does not reach the normal stacking position, and a new paper is further conveyed thereon. In such a state, it becomes difficult to eliminate the paper misalignment in the normal alignment operation. In order to avoid the occurrence of the above-described state, it is conceivable to sufficiently perform the alignment operation so as not to cause misalignment of sheets. However, since the above state rarely occurs, if the alignment operation is sufficiently performed every time to avoid this, in most cases, an excessive alignment operation is performed in a normal paper stacking state. There are problems such as a decrease in productivity.

  The present invention has been made against the background of the above circumstances, and enables the control of a closed loop that feeds back the leading edge position of a sheet that is actually transported and aligned, thereby efficiently performing an alignment operation. An object of the present invention is to provide a post-processing apparatus that can effectively eliminate unevenness.

  That is, of the post-processing apparatus of the present invention, the first aspect of the present invention includes a stacker unit for stacking sheets on which images have been formed for post-processing, and a leading end of a new sheet transported to the stacker unit. A movement amount detecting means for detecting a movement amount when moving toward the stacking position after reaching a predetermined position of the stacker unit, and a control means for obtaining the leading edge position of the sheet based on the detection result of the movement amount detection means. It is characterized by providing.

According to the first aspect of the present invention, the front end position of the paper is obtained by the control means based on the movement amount of the paper detected by the movement amount detection means. By knowing the position of the leading edge of the paper when the paper stacking is completed, it is possible to easily know whether or not the paper has been normally stacked for each paper.
The movement amount detecting means irradiates the object with light as a measurement wave, receives the reflected light with a photodetector array, and observes the structural characteristics of the object surface, thereby detecting the object per unit time. Examples of detecting the displacement amount are given. As a result, it is possible to detect the amount of movement of the uppermost paper in the stacked paper bundle.

  A post-processing apparatus according to a second aspect of the present invention is characterized in that, in the first aspect of the present invention, the post-processing apparatus further comprises a sheet detecting means for detecting a new sheet whose leading end reaches the predetermined position.

  According to the second aspect of the present invention, it is detected by the paper detection means that the leading edge of the paper has reached a predetermined position, and the movement amount detection means can detect the movement amount of the paper starting from this timing.

  In the first or second aspect of the present invention, the post-processing device according to the third aspect of the present invention is newly added to the predetermined position when the movement amount information is newly detected at the predetermined position by the movement amount detection means. It is characterized in that it is determined that the sheet has been conveyed and the leading edge has been reached.

  According to the third aspect of the present invention, the detection position of the movement amount detection means is set to the predetermined position, and when the movement amount information is newly obtained, it can be regarded as detection of the leading edge of the sheet at the predetermined position. it can. That is, in the embodiment of the present invention, the movement amount detecting means can also be used as the paper detecting means.

  The post-processing apparatus according to a fourth aspect of the present invention is the post-processing apparatus according to any one of the first to third aspects of the present invention, wherein the detected movement amount is a predetermined amount after the leading edge of a new sheet reaches the predetermined position. It is the amount of movement of the paper within the time.

  Since it is possible to predict the time for the sheet to move to the normal stacking position after reaching the leading edge at the predetermined position, in the fourth aspect of the present invention, at least the movement time is used for detecting the movement amount. By securing the time and detecting the amount of movement of the sheet, the amount of movement until the leading edge of the sheet reaches the stacking position can be obtained. Therefore, the predetermined time can be set while minimizing the travel time. Note that since the paper moving speed may vary individually, it is desirable to add the time when the fluctuation is predicted to the moving time to the predetermined time.

  In a post-processing apparatus according to a fifth aspect of the present invention, in any one of the first to third aspects of the invention, the movement amount detection unit can detect the movement amount of the paper within a predetermined time, and the control The means is characterized in that the amount of movement of the sheet is calculated by integrating the amount of movement of the sheet within a predetermined time obtained sequentially.

  According to the fifth aspect of the present invention, in the case of the movement amount detecting means for detecting the movement amount of the paper every predetermined time, the cumulative movement amount of the paper can be known by integrating the movement amounts.

  The post-processing apparatus according to a sixth aspect of the present invention is the post-processing apparatus according to any one of the first to fifth aspects of the present invention, wherein the control means is a sheet that has been transported to a normal stacking position after the leading edge has reached the predetermined position. Based on a comparison between the normal movement amount of the paper and the movement amount of the newly conveyed paper detected by the movement amount detecting means, the newly conveyed paper with respect to the leading edge position of the paper at the normal stacking position The amount of deviation of the tip position at the stacking position is obtained.

  According to the sixth aspect of the present invention, by comparing the normal sheet movement amount obtained in advance with the actually detected sheet movement amount, it is determined how much the actually loaded sheets are from the normal position. It is possible to know whether or not there is a deviation amount.

  A post-processing apparatus according to a seventh aspect of the present invention is characterized in that, in the sixth aspect of the present invention, a storage unit for storing the normal movement amount in advance is provided.

  In the post-processing apparatus according to an eighth aspect of the present invention, in the sixth aspect of the present invention, the control means determines that a stack failure or a JAM has occurred when the amount of deviation of the leading edge position of the paper exceeds a predetermined threshold. Features.

  According to the eighth aspect of the present invention, it is possible to determine whether the stack is defective or the occurrence of JAM is based on the deviation amount of the sheet. In this determination, a stepwise threshold is set, and it is determined whether or not the stack is defective by comparing with a small value threshold. If this threshold is exceeded, whether or not JAM is generated by comparing with a larger value threshold. You may make it determine whether or not.

  A post-processing apparatus according to a ninth aspect of the present invention is characterized in that, in the eighth aspect of the present invention, a storage unit for storing the threshold value in advance is provided.

  The post-processing apparatus according to a tenth aspect of the present invention is characterized in that, in the eighth aspect of the present invention, the control means limits the determination of stack failure or occurrence of JAM depending on the paper type information of the paper.

  The paper movement amount detection means may not detect an appropriate movement amount depending on the paper type of the paper. In this case, the paper movement amount detection means does not determine whether a stack failure or JAM has occurred. Examples of paper that is difficult to detect include OHP film and glossy paper. Since the paper type information of the paper is acquired at the time of image formation on the image forming apparatus side, it can be acquired by receiving this information from the image forming apparatus.

  The post-processing apparatus according to an eleventh aspect of the present invention is characterized in that, in the eighth aspect of the present invention, when the control means determines that a stack is defective, the control means performs a control to execute a matching operation when the stack is defective.

  According to the eleventh aspect of the present invention, when it is determined that the stack is defective based on the amount of misalignment of the paper, it is possible to eliminate the unevenness of the paper by performing the alignment operation when the stack is defective. It should be noted that during the alignment operation, the sheet movement amount detecting means can detect the sheet movement amount to detect whether the deviation of the sheet has been eliminated or whether it has fallen within a normal value.

  According to a twelfth aspect of the present invention, in the eleventh aspect of the present invention, the control means changes the alignment operation condition at the time of stack failure according to the amount of deviation of the leading edge position of the paper. .

  According to the twelfth aspect of the present invention, it is possible to perform alignment corresponding to the amount of deviation of the sheet by changing the alignment operation condition (the rotation speed and driving time of the alignment motor) according to the amount of deviation of the sheet. That is, when the amount of deviation is large, the matching strength is sufficiently increased (increasing the number of rotations and driving time) to improve the matching, and when the amount of deviation is small, the matching strength is reduced. Therefore, it is possible to reduce unnecessary operations to increase productivity and to save energy.

  In the twelfth aspect of the present invention, in the twelfth aspect of the invention, the alignment operation condition to be changed is any one or more of an operation time, an operation speed, and an operation amount of the alignment operation. Features.

  According to a fourteenth aspect of the present invention, there is provided a post-processing apparatus according to the first to thirteenth aspects of the present invention, comprising a detecting means moving means capable of moving the moving amount detecting means relative to a bundle of sheets stacked on the stack section. And the control means controls the detection means moving means to make the distance between the movement amount detection means and the sheet bundle surface of the paper substantially constant.

  According to the fourteenth aspect of the present invention, the movement amount detection means moves relative to the sheet according to the number of sheets stacked on the stacker unit, and the distance between the movement amount detection means and the surface of the sheet bundle is reduced. The movement amount detection accuracy can be kept good by keeping it constant. The control for maintaining the distance may be performed every time a new sheet is conveyed, or may be performed every time a plurality of sheets are conveyed.

  As described above, according to the post-processing apparatus of the present invention, the stacker unit for stacking sheets on which images have been formed for the post-processing, and the leading edge of a new sheet conveyed to the stacker unit are the stacker unit. A movement amount detection means for detecting a movement amount when the paper moves toward the stacking position after reaching the predetermined position, and a control for obtaining the leading edge position of the paper based on a detection result of the movement amount detection means. Means, it is possible to control the closed loop that feeds back the leading edge position of the paper that is actually conveyed and aligned, and the alignment operation can be efficiently and effectively performed to improve the alignment performance. Productivity can be maintained as much as possible to effectively eliminate paper irregularities. For this reason, there is an effect that man-hours for quality maintenance can be reduced.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
1 and 2 are diagrams showing a mechanical configuration of the post-processing apparatus 1 and will be described below.
The post-processing apparatus has an inlet portion 1a into which an image-formed sheet transported from the image forming apparatus 100 is introduced, and a transport path continuous to the inlet portion 1a is a sub-tray sheet passing path 2 and a main tray. Branches to the sheet passing path 3. A switching gate (not shown) is provided at the branch portion to switch the paper transport direction.

  A sub-tray 16 is provided at the downstream end of the sub-tray sheet passing path 2. On the downstream side of the main tray sheet passing path 3, a stacker unit 5 for stacking sheets is installed along the vertical direction at an angle of about 70 degrees. In the stacker unit 5, the sheet transported through the main tray paper path 3 is transported onto the stacking surface of the stacker unit 5 by the transport roller 6. The sub-tray sheet passing path 2, the main tray sheet passing path 3, the transport rotor 6 and other rollers, a switching gate, and the like constitute a sheet transporting unit. Note that a stacker entrance sensor PS1 is installed in the path from the main tray sheet passing path 3 to the stacker unit 5 as shown in FIG. It is possible.

  The sheet conveyed to the stacker unit 5 as described above falls by its own weight along the stacking surface of the stacker unit 5. As shown in FIG. 4, a movable rear end stopper 5a is provided on the lower end side of the stacker unit 5. When the stacker unit 5 is stacked, the sheet that falls by its own weight abuts against the rear end stopper 5a and reaches the stacking position. Position. Further, the stacker unit 5 is provided with a swing belt 8 that swings by a stacker entrance motor 7, and the swing belt 8 is hung on a vertical alignment roller 9. Along with the swinging motion by the swing belt 8, it is rotationally driven by the stacker entrance motor 7. The sheets transported to the stacker unit 5 fall on the stacking surface by their own weight as described above, and are stacked at a normal position while being vertically aligned by the vertical alignment roller 9 that rotates while swinging.

The stacker unit 5 is provided with alignment plates (not shown) on both sides, and the sheets can be aligned in the horizontal direction by swinging the alignment plates in the horizontal direction. The stacker entrance motor 7, the swing belt 8, the vertical alignment roller 9, the alignment plate (not shown), and the like constitute an alignment means.
Note that the stacker unit 5 is provided with a stacker 0 sheet sensor PS2, and it is possible to detect whether or not sheets are stacked on the stacker unit 5.

  In the vicinity of the lower end side of the stacker unit 5, a paper movement amount detection sensor 10 is installed as a paper movement amount detection means. The paper movement amount detection sensor 10 irradiates light on the uppermost layer of the laminated surface as a measurement wave, receives the reflected light with a photodetector array (not shown), and observes the structural features of the paper surface. It detects the amount of paper movement per unit time. An example of the sensor is described in JP-A-2005-206307.

A stapling unit 11 that is a post-processing unit is provided below the stacker unit 5. The stapling unit 11 is for stapling sheets stacked on the stacker unit 5 and can have a known configuration, and detailed description thereof is omitted in this embodiment.
Further, a main tray sheet passing path 12 for moving the stapled bundle of sheets is provided from the staple section 11 through the stacking surface of the stacker section 5, and the main tray sheet passing path 12 is a main tray 15 at the downstream end. It is connected to the.

Next, FIG. 3 shows functional blocks of the post-processing apparatus, which will be described below.
The control means 20 controls the entire post-processing apparatus, and is mainly composed of a CPU and a program for operating the CPU. In addition, a ROM for storing the program, a RAM for temporarily storing data, and the like can be provided. The control means 20 is communicably connected to the image forming apparatus 100 by serial communication or the like, and receives JOB information from the image forming apparatus 100. The JOB information includes the presence / absence of post-processing, the contents, Contains paper information. In addition, device information and the like are transmitted from the control unit 20 to the image forming apparatus 100.

  A storage unit 21 capable of storing data in a nonvolatile manner is connected to the control means 20. The storage unit 21 can be configured by a flash memory, an HDD, or the like, and can store a control process of the post-processing apparatus, various setting data, determination data such as inconsistency, and the like.

  The control unit 20 is connected to the above-described sheet movement amount detection sensor 10, and the detection result of the sensor is sequentially transmitted to the control unit 20. In the control unit 20, an integrated value of the sheet movement amount is calculated, and the leading end position of the sheet newly conveyed to the stacker unit 5 can be calculated.

  Further, in the control means 20, the paper conveying means 22 including the sub-tray paper passing path 2, the main tray paper passing path 3, the main tray paper passing path 12, and a switching gate (not shown) is connected in a controllable manner.

  The control means 20 is connected to the above-mentioned matching means 23 so as to be controllable, and the control means 20 controls the matching means 22 so as to perform the matching operation at a predetermined timing. Further, the control means 20 can change the condition of the alignment operation as necessary.

  Further, the control unit 20 is connected to the staple unit 11 in a controllable manner. When there is a stapling instruction based on the JOB information transmitted from the image forming apparatus 100, the control unit 20 moves the sheets stacked on the stacker unit 5 to the stapling unit 11 and performs necessary stapling processing.

Below, operation | movement of the post-processing apparatus of this embodiment is demonstrated.
An image-formed sheet conveyed from the image forming apparatus 100 is introduced into the post-processing apparatus 1 from the entrance 1a. At this time, based on the JOB information transmitted from the image forming apparatus 100 to the control unit 20, the control unit 20 controls the transport unit 22, and when post-processing is unnecessary, the sheet is transferred to the sub-tray by the operation of the switching gate. The paper is sent to the paper passing path 2 and discharged to the sub-tray 16. On the other hand, when the stapling process is required, the sheet is sent to the main tray sheet passing path 3 by the operation of the switching gate. The paper transported through the main tray paper path 3 is transported to the stacker unit 5 by the transport roller 6 while the trailing end is detected by the stacker entrance sensor PS1. The sheet conveyed to the stacker unit 5 falls on the stacking surface of the stacker unit 5 by its own weight, and operates the aligning means 23 after a predetermined time from the detection timing of the stacker entrance sensor PS1 to operate in the horizontal and vertical directions. Perform the matching operation. As described above, the vertical alignment is performed by rotating the vertical alignment roller 9 counterclockwise in the figure while the head belt 8 is swung by the stacker entrance motor 7. The newly transported sheet moves downward while receiving alignment with its own weight drop as described above. At this time, the movement amount is detected by the sheet movement amount detection sensor 10. The detection procedure will be described later.

The sheets stacked on the stacker unit 5 are abutted by the rear end stopper 5a.
FIG. 4 is a diagram showing a state in which new paper is stacked on the stacker unit 5. When normal, the new paper is abutted against the rear end stopper 5a and stacked at a normal position as shown in FIG. The On the other hand, when the paper is curled or the like, the paper does not move sufficiently as shown in FIG. 5B, and the movement of the paper stops without reaching the trailing edge stopper 5a. It becomes irregular.

  When the paper sheets sequentially stacked on the stacker unit 5 have a slight misalignment of the sheets, an alignment operation (details will be described later) at the time of misalignment to eliminate the misalignment is performed. If there is no irregularity, the alignment operation at the time of alignment failure is not performed. When a predetermined number of sheets designated by the JOB information are stacked on the stacker unit 5, the trailing edge stopper 5a is moved to introduce the sheets into the stapling unit 11, and necessary stapling processing is performed. The bundle of sheets subjected to the stapling process is discharged to the main tray 15 through the main tray passage path 12 under the control of the control unit 20.

Next, the detection of the sheet movement amount and the control contents associated therewith will be described below.
First, a procedure for detecting that the leading edge of a newly conveyed sheet has reached a predetermined position will be described with reference to the flowchart of FIG.
The control means 20 determines whether or not the paper detection flag is OFF (step A1). If the paper detection flag is ON, the amount of movement of the previous paper has been detected, and the apparatus waits until this detection is completed. If the paper detection flag is OFF, a new paper can be detected. First, the integrated movement amount is reset to 0 (step A2). Subsequently, the process which calculates | requires integrated movement amount from the detection result of the movement amount detection sensor 10 is performed (step A3). If the detection amount by the movement amount detection sensor 10 is not generated, the integrated movement amount remains zero. In the next step, it is determined whether or not the integrated movement amount exceeds 0 (step A4). If the integrated movement amount remains 0, the sheet has not reached the detection position, which is the predetermined position, so that no new detection is made by the movement amount detection sensor 10, and the procedure returns to step A3 and the above procedure is repeated.

  When the leading edge of the paper reaches the detection position, a new detection is made by the movement amount detection sensor 10, and as a result, the integrated movement amount exceeds 0 (step A4, YES). When the integrated movement amount exceeds 0, the paper detection flag is turned on and the routine proceeds to a movement amount detection routine. The paper detection procedure is to detect whether or not the leading edge of the newly transported paper has reached a predetermined position, and shows the function of the paper detection means of the present invention. The paper detection means is also used by the paper movement amount detection means.

A procedure for detecting the leading end position of the sheet is executed in accordance with the detection of the sheet at the predetermined position. The procedure will be described based on the flowchart of FIG.
First, it waits until the paper detection flag is turned on (step B1). In this determination, it is possible to proceed to the next step because the paper detection flag is set to ON in the paper detection. In the next step, after the leading edge reaches the above-mentioned predetermined position, the normal time to reach the normal stacking position is added to the additional time considering the variation, and the predetermined time is set and the timer is counted. Start (step B2). The predetermined time can be set in advance and stored in the storage unit 21 and read by the control unit 20 as necessary.

  The movement amount detection sensor 10 detects the movement amount of the paper every fixed time, and the detection result is transmitted by the control means 20 to calculate the integrated movement amount (step B3). In this embodiment, a sensor capable of detecting a movement amount of 0.23 mm per pulse in paper conveyance is employed as the movement amount detection sensor 10. The detection continues until the timer reaches the predetermined time (step B4), and when the predetermined time is reached, the paper detection flag is set to 0 (step B5), and the integrated movement amount calculated above is used as the paper movement amount. . The control means 20 reads the data of the normal sheet movement amount (from the predetermined position to the stacking position) stored in the storage unit 21 and compares the data with the detected movement amount to determine the deviation amount of the sheet front end. Calculate (step B6). Thereby, it is possible to know whether or not the sheets are normally stacked during the operation of the post-processing apparatus.

  FIG. 7 shows a timing chart for detecting the sheet movement amount. The paper detection flag is turned on for a predetermined time, and the timer count is continued. At this time, the movement amount of the paper is detected in a pulse shape by the movement amount detection sensor, and the detection result is integrated by the control means 20. In FIG. 7, the movement of the sheet is not detected within a predetermined time, and the time elapses for a certain time without increasing the integrated movement amount. This is because, as described above, an additional time in consideration of variations is added to the required time during normal operation. When the leading edge of the sheet is shifted as compared with the normal stack, normally, the movement of the sheet is not detected at a position on the left side as compared with the normal stack shown in the figure, and the integrated movement amount is smaller than that in the normal stack.

Next, a determination procedure based on the detected sheet shift amount will be described with reference to the flowchart of FIG. The storage unit 21 stores a threshold value 1 and a threshold value 2 as determination threshold values for the deviation amount, and the threshold value 2 is set to a value larger than the threshold value 1.
First, it is determined whether or not there is a deviation amount of the leading edge of the sheet detected by the above procedure (step C1). If the deviation amount is 0, it is determined that the stacking is normal (step C3) and processing is performed. Exit. When there is a grazing amount (not 0), it is determined whether or not the deviation amount exceeds a threshold value 1 (step C2). If the grazing amount is less than or equal to the threshold value 1 and is small, it is determined that the load is within the allowable range, and normal loading is determined as shown in FIG. On the other hand, when the deviation amount exceeds the threshold value 1, it is determined whether or not the deviation amount exceeds the threshold value 2 (step C4). If the amount of deviation is less than or equal to the threshold value 2, it is assumed that the alignment failure is slight, and as shown in FIG. In step C5, the paper movement amount detection sensor 10 may detect the movement amount of the paper, and it may be determined whether or not the deviation amount is equal to or less than the threshold 1 with the movement of the paper. If it is not less than 1, the number of times may be limited, for example, the alignment operation at the time of alignment failure, detection of the amount of sheet movement, and comparison determination with the threshold value 1 may be repeated.
If the amount of deviation exceeds the threshold value 2, a severe alignment failure has occurred, so the control means 20 performs JAM determination (step C6). In the JAM determination, the control unit 20 stops conveying the next sheet, instructs the image forming apparatus to interrupt the image forming operation, and also instructs the display unit of the image forming apparatus to issue a warning. Is possible.

  If the leading edge of the paper is misaligned as described above, the misalignment of the paper can be solved efficiently by performing the alignment operation at the time of poor alignment, but the strength of the alignment operation can be changed according to the amount of misalignment of the paper. Is possible. FIG. 10 shows a graph in which the matching strength is changed in accordance with the deviation amount of the paper. The larger the deviation amount is, the higher the matching strength is. Factors for the matching strength include, for example, the amount of paddle rotation provided in the matching means and the paddle driving time. Although this graph shows that the matching strength is continuously changed according to the deviation amount, the deviation amount may be changed stepwise according to the deviation amount.

Further, in each of the above procedures, the misalignment / JAM determination is performed regardless of the type of paper, but the determination may be limited depending on the paper. The procedure will be described below with reference to FIG.
First, the paper type information of the paper is acquired (step D1). The paper type information can be acquired from the image forming apparatus 100, for example. In the next step, based on the acquired paper type information, it is determined whether or not the paper type in the JOB is an OHP film (step D2). When the paper type is an OHP film, the misalignment / JAM determination function is turned off and the determination procedure is not performed (step D3). This is because with an OHP film, it is difficult to detect the amount of movement based on changes in surface properties, and it is difficult to accurately determine the amount of movement. If the paper type is not an OHP film, the determination procedure can be performed with the misalignment / JAM determination function turned on as usual. As a result, only highly accurate determination can be performed.

Further, in order to accurately detect the movement amount of the paper, the distance between the paper movement amount detection sensor 10 and the outermost surface of the paper bundle of paper can be maintained substantially constant.
The configuration will be described with reference to FIG.
The sheet movement amount detection sensor 10 can be moved forward and backward so that the sheet movement amount sensor 10 moves far and away with respect to the bundle of sheets by a sensor movement pulse motor 10b as detection means movement means. Note that it is desirable to set a reduction ratio of a drive transmission unit (not shown) so that the sheet movement amount detection sensor 10 moves approximately one sheet by the driving operation of each pulse of the sensor movement pulse motor 10b.
Further, the movement amount detection sensor 10 is provided with a paper contact detection sensor 10a that protrudes toward the paper bundle side and moves together with the sensor 10, and can detect contact with the outermost surface of the paper bundle.

The operation procedure of the above configuration will be described with reference to FIG.
First, the paper movement amount detection sensor 10 is moved backward by the drive of the sensor movement pulse motor 10b so that the paper contact sensor 10a is moved backward with respect to the outermost surface of the paper bundle (step E1). The backward movement for each pulse is repeated until the detection result of the detection sensor 10a becomes OFF (step E2). When the detection result of the paper contact detection sensor 10a is turned OFF, the paper movement amount detection sensor 10 is advanced by driving for each pulse of the sensor movement pulse motor 10b (step E3), and 1 until the paper contact detection sensor 10a is turned ON. The forward movement for each pulse is repeated (step E4). When the paper contact detection sensor 10a is turned on, the above processing procedure is terminated. In order to avoid interference between the sheet contact detection sensor 10a and the newly conveyed sheet, the sheet movement amount detection sensor 10 may be controlled to move backward by a required step after the above procedure.
According to the above procedure, the sheet movement amount detection sensor 10 and the outermost surface of the sheet bundle can have a substantially constant distance, and the accuracy of the detection result by the sheet movement amount detection sensor 10 can be increased.

  The present invention has been described above based on the above embodiments, but the present invention is not limited to the contents of the above embodiments, and it is a matter of course that appropriate modifications can be made without departing from the scope of the present invention. Is possible.

1 is an overall view showing a post-processing apparatus according to an embodiment of the present invention. Similarly, it is the enlarged view which expanded a part. Similarly, it is a functional block diagram. Similarly, it is a diagram showing a stacking state at the time of new paper conveyance. Similarly, it is a flowchart showing a procedure of paper detection. Similarly, it is a flowchart showing a procedure for detecting the leading end position of a sheet. Similarly, it is a timing chart when detecting the amount of paper movement. Similarly, it is a figure which shows the determination procedure corresponding to the detected paper deviation | shift amount. Similarly, it is a figure which shows the state in which the shift | offset | difference of the paper has arisen. Similarly, it is a figure which shows the relationship between the deviation | shift amount of a sheet | seat, and matching intensity | strength. Similarly, it is a figure which shows the determination procedure of the function ON-OFF based on paper type information. Similarly, it is a diagram illustrating a configuration in which the distance between the sheet movement amount detection sensor and the sheet bundle surface is kept constant. Similarly, it is a flowchart showing a procedure for keeping the distance between the sheet movement amount detection sensor and the sheet bundle surface constant.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Post-processing apparatus 5 Stacker part 7 Stacker entrance motor 8 Swing belt 9 Vertical alignment roller 10 Paper movement amount detection sensor 11 Staple part
20 control means 21 storage unit 23 matching means 100 image forming apparatus

Claims (14)

  A stacker unit that stacks sheets on which images have been formed in preparation for post-processing, and when the leading edge of a new sheet transported to the stacker unit reaches a predetermined position of the stacker unit and then moves toward the stacking position. A post-processing apparatus comprising: a movement amount detection means for detecting a movement amount of the paper; and a control means for obtaining a leading end position of the paper based on a detection result of the movement amount detection means.   The post-processing apparatus according to claim 1, further comprising a sheet detection unit configured to detect a new sheet whose leading end reaches the predetermined position.   2. The apparatus according to claim 1, wherein when the movement amount information is newly detected at the predetermined position by the movement amount detection unit, it is determined that a new sheet has been conveyed to the predetermined position and the leading end has been reached. Or the post-processing apparatus of 2.   The amount of movement detected in the above is the amount of movement of the paper within a predetermined time after the leading edge of a new paper reaches the predetermined position. Post-processing device.   The movement amount detection means can detect the movement amount of the paper within a predetermined time, and the control means calculates the movement amount of the paper by integrating the obtained movement amounts of the paper within the predetermined time. The post-processing apparatus according to any one of claims 1 to 4, wherein   The control means includes a normal movement amount of the paper conveyed to a normal stacking position after the leading edge reaches the predetermined position, and a movement amount of the newly conveyed paper detected by the movement amount detection means. 6. The deviation amount of the leading edge position at the stacking position of the newly transported paper with respect to the leading edge position of the paper at a normal stacking position is obtained based on the comparison of the above. The after-treatment device described in   The post-processing apparatus according to claim 6, further comprising a storage unit that stores the normal movement amount in advance.   The post-processing apparatus according to claim 6, wherein the control unit determines that a stack failure or a JAM has occurred when a deviation amount of the leading edge position of the sheet exceeds a predetermined threshold.   The post-processing apparatus according to claim 8, further comprising a storage unit that stores the threshold value in advance.   9. The post-processing apparatus according to claim 8, wherein the control unit restricts the determination of stack failure or occurrence of JAM depending on paper type information of paper.   9. The post-processing apparatus according to claim 8, wherein, when it is determined that the stack is defective, the control unit performs control to execute an alignment operation when the stack is defective.   12. The post-processing apparatus according to claim 11, wherein the control unit changes an alignment operation condition at the time of stack failure according to a deviation amount of a leading end position of the sheet.   The post-processing apparatus according to claim 12, wherein the matching operation condition to be changed is any one or more of an operation time, an operation speed, and an operation amount of the alignment operation.   Detection means moving means capable of moving the movement amount detection means with respect to a bundle of sheets stacked on the stack section is provided, and the control means controls the detection means movement means to control the movement amount detection means. The post-processing apparatus according to claim 1, wherein a distance between the sheet and the surface of the sheet bundle is substantially constant.

Images