JP5063536B2 - Paper transport device, paper punching device, paper processing device, image forming device, light amount adjustment method, and computer program - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that conveys a recording sheet (sheet-like recording medium—herein simply referred to as “sheet”), and performs a predetermined process on the recording sheet conveyed by the sheet conveying apparatus. Paper processing apparatus, image forming apparatus such as a copier, printer, facsimile machine, and digital multi-function peripheral equipped with the paper processing apparatus, a light amount adjustment method executed by these apparatuses, and a method for executing the light amount adjustment method by a computer It relates to a computer program.

  In the punching device portion of the paper post-processing device, the position of the side edge of the paper is measured to improve the accuracy of the punching hole position, and the punching position is set based on the position of the side edge. As such a technique, for example, the inventions described in Patent Documents 1 and 2 are known.

  Among these, Patent Document 1 discloses a punching unit that includes a punching unit that punches a sheet in a direction crossing the sheet transporting direction, and that can move in a direction crossing the sheet transporting direction. Detection means for detecting one side end parallel to the conveyance direction, and movement of the punching position of the punching means in a direction intersecting with the sheet conveyance direction based on the sheet side edge position information detected by the detection means There is described a sheet punching device characterized in that the sheet punching device moves in the vicinity of the sheet side end portion in advance based on the conveyed sheet size information.

  However, due to the improvement of the paper conveyance speed and the printing speed, the time during which the detection means at the paper side edge can be moved is shortened. By moving the detection means at the side edge, it is technically necessary to increase the speed. I can not cope. In view of this, in an image forming apparatus, CIS is often used for measurement of a sheet side end. For example, in the invention described in Patent Document 2, a CIS (contact image sensor) is arranged in the paper passage area so that the read pixels are aligned in the vertical direction with respect to the paper conveyance direction, so that 1/7 of all the read pixels. Corresponding part of the read pixels are repeatedly read with a short period TS, and the leading end position of the conveyed paper is detected. Then, based on the timing at which the leading end position of the paper is detected, writing in the sub-scanning direction of the laser irradiated on the photosensitive drum is started after waiting for a predetermined time. Further, read pixels corresponding to 6/7 of all the read pixels are read in a long cycle, and the lateral end position of the conveyed paper is detected. Based on the detected lateral edge position of the paper, the amount of deviation is calculated to correct the writing position of the paper in the main scanning direction.

  As described above, the CIS can be used to detect the sheet-side end portion, and the speed can be increased.

  On the other hand, as described in Patent Document 4, the CIS needs to adjust the amount of LED light so that the CIS output level becomes a certain level. An image forming apparatus described in Patent Document 4 includes a photoelectric conversion unit in which photoelectric conversion elements are arranged in a line in a direction orthogonal to a recording medium conveyance direction of a recording medium conveyance path, and a recording medium in the vicinity of the photoelectric conversion unit. Illuminating means for illuminating the light source, light amount adjusting means for adjusting the light amount of the illuminating means, and charge accumulation time control means for controlling the charge accumulation time of the photoelectric conversion means, and adjusting the output level of the photoelectric conversion means to the light quantity adjusting means and Although the adjustment is performed by the charge accumulation time control means, when the light amount adjustment mode is set, the transfer sheet is transported to the CIS and stopped, and in this state, the CIS LED is turned on to adjust the light amount. .

In addition, with respect to a CCD, Patent Document 5 discloses a light source that irradiates a reading target, a light amount adjusting unit that adjusts the light amount of the light source, a photoelectric conversion element that photoelectrically converts reflected light from the reading target, and a photoelectric conversion. Amplifying means for amplifying the analog image signal detected by the element and a reference white board for adjusting the reference white board reading level, and adjusting the light quantity of the light quantity adjusting means according to the reference white board level obtained by reading the reference white board. An image forming apparatus provided with a control unit is described. In this image forming apparatus, adjustment is performed in advance so that the reading level of the reference white plate becomes a predetermined level. In any case, it is necessary to adjust the light amount on the light source side when reading.
Japanese Patent No. 3363725 Japanese Patent Laid-Open No. 10-194557 JP 2003-248410 A JP 2006-221080 A JP 2007-81696 A

  As described above, it is necessary to perform the same adjustment method in the paper post-processing apparatus equipped with the CIS as a means for measuring the paper side end portion, but there is a problem unique to the post-processing apparatus. That is, when CIS light quantity adjustment is performed using paper or a reference white plate, they are soiled by toner or paper dust.

  For example, when a sheet is conveyed from the image forming apparatus in order to perform the CIS adjustment method described in Patent Document 4, the sheet to which toner or paper dust inside the main body is adhered is conveyed, and the reference sheet becomes dirty. Therefore, normal light amount adjustment cannot be performed. In the free run mode or the adjustment mode, it is possible to carry the paper by adjusting the reference paper with the post-processing device alone, but the adjustment is made only at the factory where the shipment is confirmed. In the adjustment, the adjustment in the market becomes impossible.

  Similarly, when the CIS light amount is adjusted by adjusting the white level, since the reference white plate is in the transport path, the reference white plate becomes dirty with toner or paper dust over time, so that the normal light amount cannot be adjusted. Problems occur.

  Therefore, the problem to be solved by the present invention is that the reference white plate, which serves as a reference for adjusting the amount of light by toner or paper dust, is not contaminated, and the light source of the optical measuring means is used without passing the paper. It is to enable adjustment of the amount of light.

  In order to solve the above-mentioned problem, the first means includes: a conveying means for conveying the paper along the conveying path; and a measuring means for measuring the position of the side edge of the paper conveyed by the conveying means. A measurement area for the measurement means to measure the position; a shielding means whose end protrudes from the measurement area to shield the reading object; and the measurement based on the measurement result of the shielding means. A light amount adjusting means for adjusting the light amount of the light source of the means, wherein the measuring means is located above the paper transport path, and the shielding means is located between the measuring means and the transport path. It is characterized by that.

  The second means is characterized in that, in the first means, the shielding means comprises a shielding member provided with a shielding portion painted in white as a reference.

  The third means is characterized in that, in the second means, the shielding portion painted in white as the reference is located within the measurement range of the measurement means.

  A fourth means is characterized in that, in any one of the first to third means, the shielding means is a part of a sheet guide of the transport path.

  According to a fifth means, in any one of the first to fourth means, the shielding means is arranged at a position closer to a paper center side than a side edge portion of a minimum paper size measured by the measuring means. Features.

  A sixth means is any one of the first to fifth means, wherein the measuring means is one of a contact image sensor, a line sensor, and a CCD sensor.

  The seventh means is characterized in that, in any one of the first to sixth means, the light amount adjustment by the light amount adjusting means is performed when the light amount measured by the measuring means is equal to or greater than a prescribed light amount. And

  The eighth means is characterized in that the paper punching device includes the paper conveying device according to any one of the first to seventh means.

  The ninth means is characterized in that the paper processing apparatus includes the paper conveying apparatus according to any one of the first to seventh means.

  The tenth means is characterized in that the paper processing apparatus includes the paper punching apparatus according to the eighth means.

  The eleventh means is characterized in that, in the ninth or tenth means, when the light quantity measured by the measuring means is less than a prescribed light quantity, an error notification is given to the apparatus that supplies the paper. .

  A twelfth means is characterized in that the image forming apparatus includes a sheet conveying device according to any one of the first to seventh means.

  A thirteenth means is characterized in that the image forming apparatus includes the paper punching device according to the eighth means.

  A fourteenth means is characterized in that the image forming apparatus includes a sheet processing apparatus according to any one of the ninth to eleventh means.

  The fifteenth means includes a transport means for transporting the paper along the transport path, a measuring means for measuring the position of the side edge of the paper transported by the transport means, and the measuring means measures the position. And a shielding means for shielding an object to be read by projecting an end portion of the measurement area, the measuring means is located above the paper transport path, and the shielding means It is located between the measurement means and the conveyance path, and the measurement means adjusts the light amount of the light source based on the measurement result of the shielding means protruding into the measurement area.

  The sixteenth means includes a conveying means for conveying the paper along the conveying path, a measuring means for measuring the position of the side edge of the paper conveyed by the conveying means, and the measuring means measures the position. And a shielding means for shielding an object to be read by projecting an end portion of the measurement area, the measuring means is located above the paper transport path, and the shielding means In a computer program for executing a light amount adjustment of the measuring unit of the paper transporting device positioned between the measuring unit and the transporting path by a computer, the measuring unit of the measuring unit is based on a measurement result of the shielding unit protruding into the measuring region. A procedure for adjusting the light amount is provided.

  In the embodiment described later, the conveying means is the entrance (conveying) roller 1, the conveying rollers 2 and 3, the measuring means is the CIS 201, the measuring area is the reading detection range (measuring area) R, and the shielding means is the shielding plate 202. Further, the light quantity adjusting means is in the CPU 111 and the LED driver 121, the light source is in the LED provided in the CIS 201, the paper punching device is in the punching device (punch device) 100, the paper processing device is in the paper post-processing device PD, and the image forming apparatus. Corresponds to the code PR.

  According to the present invention, since the shielding means is disposed at a position not contaminated by toner or paper dust, the shielding means for adjusting the light amount by toner or paper dust is not contaminated, and the paper is not passed through without passing through the paper. The light quantity of the light source of the automatic measuring means can be adjusted.

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

<overall structure>
FIG. 1 is a diagram illustrating a system configuration of an image forming system including a sheet post-processing apparatus and an image forming apparatus as a sheet processing apparatus according to an embodiment of the present invention. In FIG. Part of the device is shown.

  In FIG. 1, a sheet post-processing apparatus PD is attached to a side portion of the image forming apparatus PR, and a recording medium ejected from the image forming apparatus PR, here, a sheet is guided to the sheet post-processing apparatus PD. The paper passes through a transport path having post-processing means (in this embodiment, a punching device (punch device) 100 as punching means) for performing post-processing on one sheet of paper, a transport path leading to the upper tray 141, and a shift tray The branching claw 15 and the branching claw 16 are configured to distribute to a conveyance path leading to 142, a conveyance path leading to a processing tray (hereinafter also referred to as a staple processing tray) F that performs alignment, stapling, and the like.

  The paper that is sorted by the branching claw 15 and the branching claw 16 and guided to the staple processing tray F and aligned and stapled by the staple processing tray is shifted by the shift guide 142 and the movable guide 55 by the shift guide plate 54 and the movable guide 55. A sheet that has been folded in the middle folding processing tray G passes through the paper discharge conveying path. Guided to lower tray 143. Further, a branching claw 17 is disposed in the transport path for transporting paper from the branching claw 16 to the staple processing tray F. The branching claw 17 is held in the state shown in the figure by a low-load spring (not shown), and after the trailing edge of the sheet conveyed by the conveying roller 7 passes through it, the conveying rollers 9 and 10 and the staple discharge roller 11 Among them, at least the transport roller 9 is reversed, and the rear end of the sheet is guided to the sheet storage portion E by the pre-stack roller 8 and stays, and is then superposed and transported on the next sheet. By repeating this operation, it is possible to convey two or more sheets in a superimposed manner. In order to detect the position of the paper, paper detection sensors 304 and 305 are provided at positions close to each other on the upstream side in the paper transport direction of the transport roller 9 and on the downstream side in the paper transport direction of the transport roller 10, respectively.

  An inlet sensor 301 that detects a sheet received from the image forming apparatus, an inlet (conveyance) roller 1 downstream, and a perforation are disposed on the transport path positioned on the uppermost stream side of the sheet post-processing apparatus PD that receives the sheet from the image forming apparatus PR side. The apparatus 100, the conveyance roller 2, the branching claw 15, and the branching claw 16 are sequentially arranged. The branch claw 15 and the branch claw 16 are held in the state shown in FIG. 1 by a spring (not shown), and when the solenoid (not shown) is turned on, the branch claw 15 rotates upward and the branch claw 16 rotates downward. The paper is distributed to each of the above-mentioned conveyance paths. Further, a hopper 101 is provided below the punching device 100 to store drilling scraps punched by the punching device 100. The hopper 101 is configured such that the front door of the sheet post-processing apparatus PD can be opened and taken out as needed to discard perforated waste. For this reason, a full sensor (not shown) for detecting the accommodation state of perforated waste is installed.

  When guiding the sheet to the upper tray 141, the branching claw 15 is in the state of FIG. 1 and the solenoid is OFF. When guiding the sheet to the conveyance path C, the branching claw 15 is turned on by turning on the solenoid from the state of FIG. And the branch claw 16 are rotated downward, and the sheet is discharged onto the upper tray 141 via the transport rollers 3 and 4 and the upper discharge roller 5. The state of paper discharge is detected based on the detection output of the upper paper discharge sensor 302. When the sheet is guided to the staple processing tray F, the branching claw 16 is in the state of FIG. 1 and the solenoid is turned off, and the branching claw 15 is turned upward by turning on the solenoid from the state of FIG. .

  In this sheet post-processing apparatus, punching (punching device 100), sheet alignment + edge binding (jogger fence 53, end-face stitching stapler S1), sheet alignment + saddle stitching (jogger fence 53, saddle stitching stapler) Each process such as S2), paper sorting (shift tray 142), and middle folding (folding plate 74, folding roller 81) can be performed.

  The shift tray discharge section for discharging sheets to the shift tray 142 includes a shift discharge roller 6, a return roller 13, a paper surface detection sensor 330, a shift tray 142, a shift mechanism and a shift tray lifting / lowering mechanism (not shown). Consists of. The shift paper discharge roller 6 has a drive roller 6a and a driven roller 6b. The driven roller 6b is supported on the upstream side in the paper discharge direction, and is rotatable at a free end portion of an open / close guide plate that is swingable up and down. It is supported. The driven roller 6b abuts on the driving roller 6a by its own weight or urging force, and the paper is nipped between the rollers 6a and 6b and discharged. When the bound sheet bundle is discharged, the open / close guide plate is pulled upward and returned at a predetermined timing. This timing is determined based on the detection signal of the shift paper discharge sensor 303. The The stop position is determined based on the detection signal of the paper discharge guide plate opening / closing sensor, and is driven by the paper discharge guide plate opening / closing motor.

  The staple processing tray F for performing the staple processing is configured and operates as follows.

    The sheets guided to the staple processing tray F by the staple discharge roller 11 are sequentially stacked on the staple processing tray F. In this case, alignment in the vertical direction (paper conveyance direction) is performed by the tapping roller 12 for each sheet, and alignment in the horizontal direction (direction perpendicular to the sheet conveyance direction—also referred to as the sheet width direction) is performed by the jogger fence 53. The end-face stitching stapler S1 is driven by the staple signal from the control device between the end of the job, that is, from the last sheet of the sheet bundle to the first sheet of the next sheet bundle, and the binding process is performed. The sheet bundle subjected to the binding process is immediately sent to the shift paper discharge roller 6 by the discharge belt 52 with the discharge claw 52a protruding, and is discharged to the shift tray 142 set at the receiving position.

  The home position of the discharge claw 52 a is detected by a discharge belt HP sensor 311, and the discharge belt HP sensor 311 is turned on / off by a discharge claw 52 a provided on the discharge belt 52. Two discharge claws 52a are arranged at opposing positions on the outer periphery of the discharge belt 52, and the sheet bundle stored in the staple processing tray F is moved and conveyed alternately. Further, if necessary, the discharge belt 52 is rotated in the reverse direction, and the sheet bundle accommodated in the staple processing tray F on the back surface of the discharge claw 52a and the discharge claw 52a on the opposite side waiting to move the sheet bundle from now on is conveyed. It is also possible to align the direction tips. Therefore, the discharge claw 52a also functions as a means for aligning the sheet bundle in the sheet conveyance direction.

  Further, on the drive shaft of the discharge belt 52 driven by the discharge motor, the discharge belt 52 and its drive pulley are arranged at the alignment center in the paper width direction, and the discharge roller 56 is arranged and fixed symmetrically with respect to the drive pulley. Has been. Further, the peripheral speed of these discharge rollers 56 is set to be higher than the peripheral speed of the discharge belt 52. The hitting roller 12 is given a pendulum motion by a hitting SOL (solenoid) around a fulcrum and intermittently acts on the paper fed to the staple processing tray F to hit the paper against the rear end fence 51. The hitting roller 12 rotates counterclockwise. The jogger fence 53 is driven via a timing belt by a jogger motor capable of forward and reverse rotation, and reciprocates in the paper width direction.

  The end surface binding stapler S1 is driven via a timing belt by a forward / reversely movable stapler moving motor, and moves in the paper width direction in order to bind a predetermined position of the paper edge. A stapler movement HP sensor for detecting the home position of the end-face stitching stapler S1 is provided at one end of the movement range, and the binding position in the sheet width direction is determined by the amount of movement of the end-face stitching stapler S1 from the home position. Be controlled. The saddle stitching stapler S2 is disposed such that the distance from the trailing edge fence 51 to the needle striking position of the saddle stitching stapler S2 is equal to or longer than a distance corresponding to half of the conveyance direction length of the maximum sheet size capable of saddle stitching, and Two are arranged symmetrically with respect to the alignment center in the paper width direction and fixed to the stay. Since the saddle stitching stapler S2 itself is a known configuration, a detailed description thereof will be omitted here. However, when performing saddle stitching, the jogger fence 53 aligns the direction perpendicular to the sheet conveyance direction and strikes the trailing edge fence 51. After the conveyance direction of the sheet is aligned by the roller 5, the discharge belt 52 is driven and the trailing end of the sheet bundle is lifted by the discharge claw 52a, and the central portion in the conveyance direction of the sheet bundle is located at the binding position of the saddle stitching stapler S2. And then stop at this position to execute the binding operation. Then, the bound sheet bundle is conveyed to the middle folding processing tray G side and folded in half. In the figure, reference numeral 310 denotes a paper presence / absence sensor that detects the presence / absence of paper on the staple processing tray F.

  The sheet bundle that has undergone saddle stitching in the staple processing tray F is folded in the middle of the sheet. This middle folding is performed in the middle folding processing tray G. For this purpose, it is necessary to transport the bound paper bundle to the middle folding processing tray G. In this embodiment, a sheet bundle deflecting unit is provided on the most downstream side in the conveyance direction of the staple processing tray F, and conveys the sheet bundle to the middle folding processing tray G side. The sheet bundle deflection mechanism includes a branch guide plate 54 and a movable guide 55. The branch guide plate 54 is provided so as to be swingable in the vertical direction around a fulcrum. A pressure roller 57 that is rotatable is provided on the downstream side of the branch guide plate 54 and is pressed toward the discharge roller 56 by a spring. Further, the position of the branch guide plate 54 is defined by the contact position with the cam surface of the cam that rotates by obtaining a driving force from the bundle branch drive motor. The movable guide 55 is swingably supported on the rotation shaft of the discharge roller 56, and a link (not shown) is rotatably connected to one end of the movable guide 55 (the end opposite to the branch guide plate 54) by a connecting portion. It is driven by the arm and the stop position is set.

  The middle folding processing tray G is a bundle installed along the bundle conveyance guide plate, the lower 92, 91, and the bundle conveyance guide plate upper 92 that are installed substantially vertically from the outer periphery of the discharge roller 56 on the movable guide 55 side. A pair of folding rollers 81 provided on adjacent portions of the lower and upper portions of the conveying rollers (pairs) 71 and 72, on the bundle conveying guide plate 92 and 91, and a sheet discharging conveying path extending horizontally from the nip to the folding rollers 81. A lower discharge roller 83 provided on the most downstream side of the discharge conveyance path, a folding plate 74 provided so as to be able to reciprocate in a horizontal direction with respect to the nip of the folding roller 81, and a bundle conveyance guide plate lower 91 A movable rear end fence 73 projecting into the conveyance path, a moving mechanism for moving the movable rear end fence 73 up and down, and downstream of the bundle conveying roller 72 in the sheet bundle conveying direction and upstream of the folding position. Bundle reach 321, a movable rear end fence HP sensor 322 for detecting the home position of the movable rear end fence 73, and a folded portion passage sensor 323 for detecting a sheet bundle passing through the paper discharge conveyance path. ing. The folding plate 74 has a function of reciprocating in the horizontal direction with respect to the nip of the folding roller 81 as described above, folding the sheet bundle and pushing it into the nip of the folding roller 81.

  In this embodiment, it is assumed that the sheet folding is performed by folding a bundle of sheets. However, the present invention can be applied to the case of folding one sheet. In this case, saddle stitching is not required for only one sheet, so when one sheet is discharged, the sheet is fed to the middle folding processing tray G side, folded by the folding plate 74 and the folding roller, and discharged to the lower tray 143. Make paper.

<Punching device>
2 is a diagram showing the arrangement and schematic configuration of the horizontal registration detection unit A and the drilling unit B of the punching device 100, FIG. 3 is a diagram showing the relationship between the shielding plate (reference white plate) and the CIS, and FIG. 4 is the horizontal registration detection unit. It is a side view of A.

  In FIG. 2, the punching apparatus 100 includes a lateral registration detection unit A and a punching unit B. The punching unit B is inserted into a punch blade 415, a holder 437 provided integrally with an upper end portion of the punch blade 415, and a holder 437. A cam 438 that is eccentrically engaged with the shaft 416, a motor 418 that drives the punch blade 415 via a clutch 417, and a second stepping motor that moves the punch blade 415 in a direction perpendicular to the sheet conveying direction. 423, a timing belt 424, a gear / pulley 436, a rack 419, and upper and lower guide plates 433 and 435. A punching waste guide 405 is provided below the punch blade 415 to guide the drilling waste to the hopper 101 that collects the punching waste. Reference numeral 420 is a punch guide, and reference numeral 421 is a punch guide.

  In the sheet post-processing apparatus FR configured as described above, first, the leading edge of the sheet conveyed from the image forming apparatus PR is abutted against the nip of the skew correction roller pair (entrance roller pair) 1 that is stopped. . After the sheet is abutted for a certain time and the sheet is bent by an appropriate amount, the skew correction roller pair 1 is rotated to resume the sheet conveyance. The stop time and rotation start timing of the skew correction roller pair 1 are determined by using the leading edge detection performed by the entrance sensor 301 as a trigger. The paper whose skew has been corrected by the skew correction roller 1 then passes through the lateral registration detection unit A, and then passes through the punching unit B.

  In the lateral registration detection unit A, the CIS 201 as a paper edge position measuring unit for detecting the edge position parallel to the conveyance direction of the paper conveyed to the unit A has a reading line direction in a direction orthogonal to the conveyance direction. It is installed on a paper guide (not shown) so as to be positioned. In this embodiment, the CIS is used as the paper edge position measuring means, but a line sensor or a CCD sensor can be used.

  The movement driving source of the drilling unit B is the second stepping motor 423, from which the driving force is transmitted to the gear / pulley 436 via the timing belt 424 to rotate. A rack 419 is engaged with the gear of the gear / pulley 436, and the rack 419 moves in both directions indicated by an arrow X in FIG. The rack 419 is mounted on the punch lower guide plate 421, and all the constituent units for punching (punch blade 415, punch upper guide 420, shaft 416, cam 438, holder 437, clutch 417, motor 418) are all punch lower guide plates. Since the unit 421 is coupled, the component unit to be punched by the movement of the rack 419 moves in a direction (arrow X direction) perpendicular to the transport direction.

<Control device>
As shown in FIG. 5, the control device 110 includes a microcomputer having a CPU 111, an I / O interface 112, and the like, and includes switches on the operation unit (operation panel 113) of the image forming apparatus PR, an upper discharge tray 141, Signals from various sensors such as the paper discharge sensors 302, 303, and 323 that detect the paper discharge state to the shift tray 142, the lower paper discharge tray 143, and the paper surface detection sensor 330 that detects the paper surface height on the shift tray 142. Is input to the CPU 111 via the I / O interface 112. Based on the input signal, the CPU 111 operates the punch blade 415 in the vertical direction of the punching device 100, the operation of the jogger fence 53 in the direction orthogonal to the paper conveyance direction in the staple processing tray F, the end face binding stapler S1 or the saddle stitching. The binding operation by the stapler S2, the discharge operation of the bundle of sheets after binding, the lifting and lowering operation of the shift tray 142, and the operation of the tapping roller 12 that taps the sheet to the rear end fence 51 side in order to align the direction parallel to the sheet transport direction. The operation of each of the conveying rollers 1, 2, 3, 4, 5, 6, 7, 9, 10, and 11 is controlled, and the sheet edge position measurement is performed based on the detection output of the CIS 201.

  The control of the sheet post-processing apparatus PD including the above control is performed by the CPU 111 developing a program written in a ROM (not shown) on a RAM (not shown) and executing the program while using the RAM as a work area. Also, the program data can be downloaded from a server via a network or a recording medium via a recording medium driving device, or can be upgraded. Furthermore, if the paper post-processing device PD is integrated with the image forming device PR, or if the paper post-processing device PD is incorporated in the housing of the image forming device PR, the paper post-processing device PD is installed in the image forming device PR. That's right.

<Operation>
The sheet that has passed through the image forming apparatus is conveyed to the punching apparatus 100. At this time, skew is often generated in the paper, and unless the skew is corrected, the accuracy of the hole position is not improved. Therefore, when punching, the sheet is brought into contact with the nip of the stopped roller, and the skew is corrected by aligning the leading ends at the nip position.

  <Skew Correction> FIG. 6 shows the detection timing of the leading edge of the sheet of the entrance sensor 301 and the drive timing of the entrance (conveyance) roller 1. The leading edge of the sheet conveyed from the image forming apparatus PR is abutted against the stopped skew correction roller pair (entrance roller) 1. After a certain amount of time (until timing TM1) and the sheet being struck and deflected by an appropriate amount, the entrance roller 1 is accelerated (from timing TM1 to TM2) and is operated faster than the receiving speed by the amount of excess deflection (timing TM2). From TM3 to TM3), the bend is taken, and when the bend is eliminated, the sheet is returned to the receiving speed (from timing T3M to TM4), and thereafter the sheet is conveyed at the receiving speed (after timing TM4). The stop time and rotation start timing of the entrance (conveyance) roller 1 are performed using the entrance sensor 301 as a trigger.

FIG. 7 is a flowchart showing a control procedure for operating the entrance (conveyance) roller 1 in accordance with the detection timing of the entrance sensor 301.
In this processing procedure, when the sheet is discharged from the image forming apparatus PR (step S101—YES) and the entrance sensor 301 is turned on (step S102—YES), the counter T1 is cleared and counting is started (step S103). When the entrance sensor 301 is turned on and a certain time (TM0 to TM1) elapses (step S104-YES), the entrance (conveyance) roller 1 is accelerated to the acceleration speed (step S105, TM1 to TM2), and the acceleration operation is completed. (Step S106—YES, TM2), the counter T1 is cleared, and the next count is started (Step S107). When a predetermined time has elapsed (step S108-YES, TM2 to TM3), an operation of decelerating the entrance (conveyance) roller 1 to the receiving speed is started (step S109-TM3). In this way, correction of the skew of the sheet is executed at the position of the entrance (conveyance) roller 1.

<Registration correction>
For the skew-corrected paper, the position information of the lateral resist is acquired by the CIS 201 installed as a measuring means for measuring the side edge of the paper. FIG. 8 is a diagram for explaining the measurement start timing for CIS 201 paper. As the measurement start timing, a side end portion in the main scanning direction of the holed hole Pa position as shown in FIG. 8 is preferable so that the skew can be excluded as much as possible. From the ON signal (paper leading edge detection) or OFF signal (paper trailing edge detection) of the entrance sensor 301, the measurement start timing is calculated by a timer or by a transport pulse if the drive unit of the entrance (transport) roller 1 is a stepping motor.

  FIG. 9 is a diagram showing the positional relationship between the lateral registration detection unit A, the punching unit B, and the conveyed paper using the CIS 201. As described above, the punching unit B can be moved by the second stepping motor 423 in a direction perpendicular to the paper transport direction (shown in the arrow moving direction), and in accordance with the actual position of the transported paper. By controlling the stop position of the unit B, a highly precise punching position is obtained. The end face of the paper is detected by detecting the distance indicated by L by CIS201, and the amount of deviation is calculated by calculating the difference x from the theoretical (ideal) distance M. Assuming that the punching unit B has a distance of 7.5 mm from the home stop position to the theoretical position, if the punching unit B moves (7.5 mm-x) mm in this case, the punch can be punched at an appropriate position.

  FIG. 10 is a diagram illustrating a sheet detection state using the CIS 201. Measurement is started by inputting a clock (CLK) to the CIS 201 and giving a trigger signal (TG) for starting measurement. After a predetermined number of clocks (r in the figure), one pixel from the first pixel in one clock. The CIS 201 is output every time. The sensor output has a higher output level as the reflectivity of the paper increases. Therefore, if the analog output of the sensor is binarized at an appropriate threshold level (binarized threshold (TH) in the figure), “ With “Yes” or “None”, the output can be digitized. In the example of FIG. 10, since the sensor output is low in the range (TMa) to (TMb) where there is no paper, the binarized output becomes the LOW level, and in the range where the paper is (after (TMb)) Since the output is higher than the threshold level, the binarized output becomes the HIGH level. The paper position is detected by counting the number of clocks from the trigger signal (TG) until the binarized output becomes HIGH level (position (TMb)) or by measuring the time. That is, the paper position can be detected by measuring P in the figure from the trigger signal output until the binarized output becomes HIGH level.

Since the position of the end face of the sheet is the (TMb) position from the first pixel of the CIS 201 as the lateral registration sensor (lateral registration sensor) 414,
L = P−r (1)
Will be required. This L becomes L shown in FIG. 8, and the deviation amount of the sheet is obtained by ML. Note that P is a measured value, and r is a fixed value.

<Horizontal registration displacement detection control>
FIG. 11 is a block diagram showing a circuit configuration of a lateral registration deviation detection circuit for detecting lateral registration deviation of a sheet. The paper post-processing device PD is controlled by a one-chip CPU 111, and the CPU 111 outputs a control signal (a) of the LED driver 121 and a trigger signal TG (b) for starting measurement to the CIS 201 and oscillates a clock. The clock oscillator 122 is controlled to output the clock (c).

  The analog output (d) of the CIS 201 is digitized by the binarization circuit 124, and simultaneously with the paper edge position measuring unit 125 and simultaneously with the clock (CLK) via the A / D conversion circuit 134, the CPU 111 converts the analog output (d) into a digital signal (s). Is input. The paper edge position measuring unit 125 measures the paper position by measuring the number of clocks (CLK) up to the HIGH level edge corresponding to the paper edge. The measurement result is input to the data abnormality determination unit 126 as output (e), and the obtained data is greatly deviated from the general position of the paper size, or the paper edge cannot be detected. The abnormal signal (when abnormal condition = 1) and (f) are output to each gate circuit 133, the CPU 111, and the abnormal value occurrence number counting unit 123.

  The abnormal value occurrence number counting unit 123 can count the number of abnormal signals (abnormality = 1) and (f) output from the data abnormality determining unit 126. The output (g) of the counter is output to the CPU 111, and the counter contents are cleared by the counter clear signal (q) from the CPU 111. The output (h) of the measuring unit 125 is stored in the storage unit 128 by the gate circuit 132 when the data is not abnormal (the output of the data abnormality determining means is 0).

  At the time of storage, it is possible to store by paper size or to store separately by JOB content. In response to an instruction from the CPU 111, the start / setting signal (m) is output to the data average calculation unit 131, and the data (i) in the storage unit 128 is integrated after the necessary data is integrated by the data integration unit 130 (j). An average value (k) is obtained by the average calculator 131. In order to calculate the sheet edge deviation amount, a deviation amount calculation unit 127 is provided. When the input is not abnormal data by the gate circuit 133, the gate circuit 133 sends the deviation amount calculation unit 127 to the sheet edge position measurement unit 125. When the result (e) is input and the data is abnormal, the data selected by the data selection unit 129 based on the selection signal (n) from the CPU 111 is input. Based on these inputs, the deviation amount calculation unit 127 calculates the deviation amount of the sheet edge, and outputs the result (deviation amount (p)) to the CPU 111. The CPU 111 drives the second stepping motor 423 by an amount corresponding to the displacement amount based on the displacement amount (p) input from the displacement amount calculation unit 127, and moves the punch punching unit B to an appropriate position.

<Light intensity adjustment>
The light amount adjustment of the CIS 201 is performed by adjusting the output of the LED serving as the light source. This is performed by the LED driver 121 in FIG. FIG. 12 is a circuit diagram showing an LED drive circuit of CIS201. Since the LED is supplied from a single power supply VDD, PWM is used to adjust the light amount of the LED. FIG. 13 and FIG. 14 are diagrams showing the relationship between the reference white plate and plain paper when the horizontal axis is LED light quantity: PWM (%) and the vertical axis is CIS output voltage. As shown in FIG. 13, the output voltage of the CIS alone is proportional to the LED light source. Therefore, when the LED light quantity is taken on the x-axis and the CIS output voltage is taken on the y-axis, the CIS output voltage characteristics of the white plate 151 (corresponding to the reference white plate 202-hereinafter the same) are
y = ax + b
The CIS output voltage characteristic of plain paper 152 is
y = px + q
The dark output range 153 is indicated by
y = c
It can be expressed as That is, if the LED light quantity x is determined, it means that the CIS output voltage y is uniquely determined. The reverse is also true.

  Therefore, if the “LED light quantity—CIS output characteristics” of the white board 151 and the plain paper 152 are known, the characteristics of the white board 151 can be substituted with the characteristics of the plain paper 152, and vice versa. However, when a plurality of CIS 201 are considered, the output voltage characteristics of the CIS 201 have a width depending on the individual difference of the CIS 201 or the voltage fluctuation width of the power supply VDD supplied to the LED. In the light amount adjustment, the upper and lower limit values of the CIS output voltage are important values.

  From FIG. 13, it can be seen that if the amount of LED light is greater than the intersection P1 between the upper limit 153a of the dark output region 153 and the lower limit 152a of the plain paper 152, the end face of the paper can be detected. However, the larger the amount of LED light, the more the LED deteriorates. Therefore, in order to use the life of the CIS 201 for a long time, it is preferable to use it with the light amount of the LED as small as possible. The reason why the lifetime of the light receiving element is not discussed here is that the deterioration time of the light receiving element is almost negligible with respect to the deterioration time of the LED as the light emitting element.

FIG. 14 is a diagram showing the relationship between the amount of LED light and the CIS output voltage when the CIS 201 is used for a long time. When the CIS 201 is deteriorated, the CIS output voltage is attenuated even if the LED is turned on at the same PWM ratio because the light amount of the LED is attenuated. However, since the dark output range 153 has almost no change, the limit LED light amount for detecting the end face of the paper is P1 in the initial stage of using the CIS 201. become. As described above, the light quantity of the LED is attenuated, and the attenuation of the light receiving element is negligible.
P1 = αP1 ′
If so, the LED light quantity-CIS output characteristic of the white plate 151 is
y = αax + b
The LED light quantity-CIS output characteristic of plain paper 152 is
y = αpx + q
Can be expressed as

FIG. 15 is a diagram illustrating an example of CIS output voltage characteristics of the adjusted plain paper. Also in FIG. 15, the LED light amount is taken on the x axis and the CIS output voltage is taken on the y axis. In the figure, the threshold CIS output Vth takes a normal margin β when the upper limit value of the dark output region is Vlimit (= c).
Vth = Vlimit + β
And Vlimit corresponds to the binary threshold shown in FIG.

  When the initial setting of the LED light amount is P2, and the CIS output voltage becomes Vth or less, the LED light amount PWM ratio may be increased by 10%, for example, as shown in FIG. By frequently increasing the PWM ratio, it is possible to detect the end face of the sheet with a minimum amount of LED light. However, since the CIS output characteristic to be actually measured is not the plain paper 152 but the reference white plate 202, correction is necessary.

When adjusting the amount of light, the upper limit value of the fluctuation width is used as the CIS output voltage characteristic of the plain paper 152. The CIS output voltage characteristic of this plain paper 152 is y = px + q
And the CIS output voltage characteristic of plain paper 152 at that time is y = ax + b
Assume that These characteristics are obtained by evaluation, and are naturally measured by fixing the distance between the white plate 202 and the CIS 201 and the distance between the paper and the CIS 201. The details of the measurement method are omitted here. Since Vth is the threshold CIS output for the plain paper 152, it is necessary to calculate the CIS output Vth ′ for the white plate 151 at this time. The light quantity of the LED is attenuated by α, and the CIS output voltage characteristic of the plain paper 152 is y = ax + b → y = αax + b
So
y = Vth
x = P2
Is assigned,
Vth = αaP2 + b
More attenuation is
Vth = Vlimit + β
Is assigned,
α = (Vth−b) / aP2
= (Vlimit + β-b) / aP2
Is calculated.

The CIS output voltage characteristic of the white plate 151 is attenuated by α times,
y = px + q → y = αpx + q
So
y = Vth '
x = P2
Is assigned,
Vth ′ = αpP2 + q
= (Vlimit + β-b) p / a + q
Is calculated.

From the above, when the measured CIS output voltage in the white plate 151 is Vo,
Vo ≦ Vth ′ (1)
That is,
Vo ≦ (Vlimit + β−b) p / a + q
When the above is established, the LED light amount may be increased.

  FIGS. 16 and 17 are diagrams illustrating an example of a sheet conveying apparatus in which the reference white plate 202 is installed. That is, the white plate 202 serving as a reference is installed for adjusting the light amount of the CIS 201. FIG. 16 is a view of the layout of the CIS 201 and the white plate 202 from the top of the paper transport device and the front of the paper transport device of FIG. As shown in FIGS. 16 and 17, in this embodiment, the reference white plate 202 is disposed within the reading detection range of the CIS 201, vertically above the sheet conveyance path 203, and between the sheet conveyance path 203 and the CIS 201. It has a layout like this.

  Since the reference white plate 202 is used for light amount adjustment of the CIS 201, it needs a state with high precision flatness and no color unevenness. If the reference white plate 202 is positioned below the paper transport path 203 in the vertical direction, the reference white plate 202 is contaminated by paper dust or toner. Therefore, in this embodiment, the reference white plate 202 is positioned above the conveyance path 203 in the vertical direction. However, since the sheet is positioned vertically above the sheet conveyance path 203, the reference white plate 202 is also measured when reading the sheet end face. Therefore, the arrangement of the reference white plate 202 is set on the paper transport center side with respect to the paper passing position of the minimum correctable size (in this case, B5 length is taken as an example). This state is shown in FIG.

  As shown in FIGS. 16 and 18, the region where the CIS 201 measures the reference white plate 202 is only a few percent of the entire CIS 201. When adjusting the amount of light, ideally, it is desirable to judge from the output voltages of all the light receiving elements of the CIS 201. However, if the CIS 201 is used to detect the end face of the paper, the voltage level depending on the location of the CIS 201 is substantial. The difference is negligible.

  FIG. 19 is a diagram illustrating an output voltage of the CIS 201 when the reference white plate 202 is measured. The sensor output is an output level in the dark output area other than the reference white plate 202. Since the binarization threshold Vth is the threshold voltage of plain paper as described above, the binarization sensor output becomes HIGH level at the position where the reference white plate 202 is reliably detected. The CIS201 output voltage input to the CPU 111 is stored in the memory space of the CPU 111 by DMA (direct memory access) in synchronization with CLK by this external interrupt of the binary sensor output Low → High (FIG. 11). FIG. 20 is a diagram showing an output state when the reference white plate 202 is detected, and shows a state where the output 251 of the CIS 201 is A / D converted and the voltage value 252 after A / D conversion is stored in the memory space 253. Yes.

  The amount of data stored in the memory space 253 needs to be a value smaller than the CIS detection area 201a shown in FIG. For example, if the resolution per pixel is 0.1 mm and the CIS detection area 201a is 20 mm, there is an effective area for 200 pixels. If the mounting error of the reference white plate 202 is 1 mm and the margin is 1 mm, data from the top to 18 mm, that is, 180 pixels is effective as the data of the reference white plate 202. The final output voltage Vo of the reference white plate 202 can be obtained by taking an average of these, or by removing the maximum and minimum values by 10 and taking an average.

  The light quantity adjustment may be performed when the paper punching device is turned on. Alternatively, by storing the number of times the CIS 201 is driven using data that remains even when the power source such as a nonvolatile memory is turned off, useless initial operation of the CIS 201 can be reduced and the life of the CIS 201 can be improved. FIG. 21 is a flowchart illustrating a light intensity adjustment processing procedure in the paper punching device including the nonvolatile memory.

  The light amount adjustment in the paper punching device provided with the non-volatile memory is performed by the following processing procedure. That is, when the power of the paper punching device is turned on (step S201-YES), it is checked whether or not the number of CIS operations in the nonvolatile memory has reached a certain amount (step S202), and the number of operations has reached a certain amount. If it is, the CIS 201 is driven to check whether the equation (1) is satisfied (step S204). If established, the PWM ratio of the CIS light quantity is increased by 10% (step S205—see FIG. 15), the process returns to step S203, the CIS 201 is driven, and the subsequent processing is repeated. Then, at step S204, the processing ends when the expression (1) is not satisfied.

  FIG. 22 is a view for explaining a reference white plate functioning as a shielding plate. FIG. 22A shows the relationship between the CIS and the reference white plate, and FIGS. 22B and 22C show the reference white plate. Further, FIG. 3 described above is a diagram in which the shielding plate (here, the reference white plate) 202 or the shielding object is disposed within the measurement range of the sheet edge position measurement unit 125. As shown in FIG. 3, in the present embodiment, a layout is adopted in which a shielding plate (reference white plate) 202 is disposed within a reading detection range (measurement region) R of the CIS 201. FIG. 12 is an explanatory diagram showing the paper transport reference position. The shielding plate 202 or the shielding object as a shielding means blocks the optical path to the reading target of the CIS 201, and instead of reading the reading target, reads the surface of the image facing the shielding plate 202 or the shielding object in place of the shielding plate 202. It is like that. The reading detection range (measurement region) R corresponds to a range from the first pixel to the last pixel of the CIS 201 and is a range that can be read by the CIS 201.

  As described with reference to FIG. 18, the attachment position of the shielding plate 202 is closer to the center of paper conveyance than the paper passage position of the minimum correctable size (the B5 vertical size). As a matter of course, the lateral registration correction possible distance, CIS attachment error, and shield plate attachment error are taken into consideration. When the image is read with the CIS 201 in such an arrangement, the blocking plate 202 can be detected from the binarized result. In FIG. 23, a portion of the CIS 201 that is shielded by the reference white plate 202 is a detection unit 201a that detects the reference white plate (shielding plate) 202, and a portion that is not shielded is a non-detection unit 201b. Therefore, FIG. 19 can be said to be a diagram showing a detection state of the reference white plate (shielding plate) 202 of the CIS 201 at this time.

  In the present embodiment, the reference white plate 202 functions as a shielding plate or a shielding object. The shielding plate is configured by providing a member painted in white or a similar color like the reference white plate 202 or a member painted in white or a similar color. At that time, if the front surface of the reference white plate 202 is set to the white area as shown in FIG. 22B, the cost corresponding to the CIS detection area is set to the white area as shown in FIG. 22C. Can be lowered.

  Considering further cost reduction, if the reference white plate 202 and the sheet conveyance path 203 are made the same member as shown in FIG. 23, it is not necessary to provide the reference white plate 202 as an independent member, so that the cost can be reduced. Become. At that time, as described with reference to FIG. 22C, if only the vicinity of the CIS detection region is made a white region, the cost can be further reduced.

When the voltage lower than the lower limit of the dark output range 153 shown in FIGS. 13 to 15 is Vm, and the CIS 201 is functioning normally, the CIS output voltage Vo is
Vo <Vm (2)
Basically, there are only malfunctions, defective sets, harnesses, connector misconnections, etc. there,
Vo ≧ Vm (3)
The light amount adjustment is performed only when the above is established. This eliminates the need for unnecessary light amount adjustment.

  Further, if the expression (2) is satisfied, it means that a failure, a defective set, a harness, a connector connection error, or the like has occurred, so that the image forming apparatus PR side is notified and the operation is performed. It can also be displayed on the panel.

  In the present embodiment, an example in which the CIS 201 is used as the detection means for detecting the light amount is shown, but it goes without saying that a line sensor or a CCD sensor may be used instead of the CIS 201.

As described above, according to the present embodiment,
(1) Since the reference white plate 202 is disposed at a position where it is not soiled by toner or paper dust, the light amount of the light source (LED) of the CIS 201 is not contaminated by the reference white plate 202 for light amount adjustment, and the paper is not actually passed. Adjustments can be made.
(2) A shielding plate or shielding member serving as a shielding means is painted with a reference white color (white or a similar white color), or a member painted with the reference white color is shielded or shielded. By providing as an object, the light amount can be adjusted without providing the reference white plate 202 in particular.
(3) Since the part or member painted in white as the reference is set within the measurement range of CIS201, it is not necessary to add a part or member to be painted outside the measurement range. Cost can be reduced.
(4) Since the shielding plate or shielding object (reference white plate 202) is configured as a part of the guide of the conveyance path 203, it is not necessary to separately prepare a member serving as the shielding plate or shielding object, and the cost is reduced accordingly. be able to.
(5) Since the shielding plate or shielding object is arranged at a position closer to the center of the sheet than the side edge of the minimum sheet size for measuring the shielding plate, the shielding plate or shielding object can always be detected by the CIS 201, and the reading of the CIS 201 is performed. Control becomes possible.
(6) When the output voltage of the CIS 201 is lower than the lower limit of the dark output range, it means that a failure, a set failure, a harness, a connector connection error, etc. has occurred. An error is notified to the forming apparatus PR. As a result, the image forming apparatus PR can know that a failure has occurred in the sheet post-processing apparatus.
There are effects such as.

  In addition, this invention is not limited to this embodiment, It cannot be overemphasized that all the technical matters contained in the technical idea described in the claim are object.

1 is a diagram illustrating an outline of a system configuration of a system including a sheet post-processing apparatus and an image forming apparatus according to an embodiment of the present invention. It is a figure which shows arrangement | positioning and schematic structure of the horizontal registration detection unit and punching unit in this embodiment. It is a figure which shows the relationship between the shielding board and CIS in this embodiment. FIG. 3 is a side view of a lateral registration detection unit in FIG. 2. It is a block diagram which shows an example of the electrical constitution of the system of FIG. FIG. 6 is a diagram illustrating detection timing of a paper leading edge of an entrance sensor and drive timing of an entrance (conveyance) roller during skew correction. It is a flowchart which shows the control procedure processed at the timing of FIG. 6 in the case of skew correction. FIG. 6 is a diagram for explaining measurement start timing for CIS paper. It is a figure which shows the positional relationship with the horizontal registration detection unit using CIS, a punching unit, and the conveyed paper. It is a figure which shows the detection state of the paper which uses CIS. FIG. 6 is a block diagram illustrating a circuit configuration of a lateral registration deviation detection circuit that detects a lateral registration deviation of a sheet. It is a circuit diagram which shows the LED drive circuit of CIS. It is a figure which shows the relationship between a reference white board and a plain paper when a horizontal axis is LED light quantity and a vertical axis | shaft is set as the output voltage of CIS. It is a figure which shows the relationship between LED light quantity and CIS output voltage when a horizontal axis is LED light quantity and a vertical axis | shaft is CIS output voltage and CIS is used for a long period of time. It is a figure which shows the example of the CIS output voltage characteristic of adjustment plain paper, making a horizontal axis the LED light quantity and a vertical axis | shaft the output voltage of CIS. It is a figure which shows the example of the paper conveying apparatus which installed the reference | standard white board, and is the figure which looked at the layout from the upper part of the paper conveying apparatus. It is a figure which shows the example of the paper conveying apparatus which installed the reference | standard white board, and is the figure which looked at the layout from the front of a paper conveying apparatus. It is a figure which shows arrangement | positioning of a reference | standard white board. It is a figure which shows the output voltage of CIS when a reference white board is measured. It is a figure which shows the state which carries out A / D conversion of the output when a reference white board is detected, and stores the voltage value after A / D conversion in a memory space. It is a flowchart which shows the process sequence of the light quantity adjustment in the paper punching apparatus provided with the non-volatile memory. It is a figure for demonstrating the reference | standard white board which functions as a shielding board. It is a figure which shows the state of a CIS detection part and a non-detection part when a reference white board and a paper conveyance path | route are made into the same member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Entrance (conveyance) roller 2,3 Conveyance roller 100 Punching device (punch device)
110 Controller 111 CPU
121 LED driver 201 CIS (contact image sensor)
201a detector (area)
202b Non-detection part 202 Shielding plate 203 Paper conveyance path B Punching unit PD Paper post-processing device PR Image forming device R Measurement area

Claims (16)

Transport means for transporting paper along the transport path;
Measuring means for optically measuring the position of the side edge of the paper conveyed by the conveying means;
In a paper transport device having
A measurement region for the measurement means to measure the position;
Shielding means for shielding an object to be read by projecting an end of the measurement area;
A light amount adjusting means for adjusting the light amount of the light source of the measuring means based on the measurement result of the shielding means;
With
The paper conveying apparatus, wherein the measuring means is located above the paper conveyance path, and the shielding means is located between the measurement means and the conveyance path. In the paper conveyance device according to claim 1,
The sheet conveying apparatus according to claim 1, wherein the shielding means comprises a shielding member having a shielding part painted in white as a reference. In the paper conveying apparatus according to claim 2,
The sheet conveying apparatus according to claim 1, wherein the reference white-coated shielding portion is located within a measurement range of the measurement means. In the paper conveyance device according to any one of claims 1 to 3,
The sheet conveying apparatus, wherein the shielding means is a part of a sheet guide of the conveying path. 5. The sheet conveying device according to claim 1, wherein the shielding unit is disposed at a position closer to a sheet center side than a side end portion of a minimum sheet size measured by the measuring unit. Characteristic paper transport device. 6. The paper conveying apparatus according to claim 1, wherein the measuring means is one of a contact image sensor, a line sensor, and a CCD sensor. The paper conveyance device according to any one of claims 1 to 6, wherein the light amount adjustment by the light amount adjustment unit is performed when the light amount measured by the measurement unit is equal to or greater than a predetermined light amount. Paper transport device.   A paper punching device comprising the paper transport device according to any one of claims 1 to 7.   A sheet processing apparatus comprising the sheet conveying apparatus according to claim 1.   A paper processing apparatus comprising the paper punching device according to claim 8. The sheet processing apparatus according to claim 9 or 10,
A paper processing apparatus that performs error notification to a side that supplies paper when the light quantity measured by the measuring unit is less than a prescribed light quantity.   An image forming apparatus comprising the sheet conveying device according to claim 1.   An image forming apparatus comprising the sheet punching device according to claim 8.   An image forming apparatus comprising the sheet processing apparatus according to claim 9. Transport means for transporting paper along the transport path;
Measuring means for optically measuring the position of the side edge of the paper conveyed by the conveying means;
A measurement region for the measurement means to measure the position;
Shielding means for shielding an object to be read by projecting an end of the measurement area;
With
The measuring means is located above the paper conveyance path, and the shielding means is located between the measurement means and the conveyance path,
The light quantity adjustment method, wherein the measurement means adjusts the light quantity of the light source based on a measurement result of the shielding means protruding into the measurement area. Transport means for transporting paper along the transport path;
Measuring means for optically measuring the position of the side edge of the paper conveyed by the conveying means;
A measurement region for the measurement means to measure the position;
Shielding means for shielding an object to be read by projecting an end of the measurement area;
With
The measuring unit is positioned above the sheet conveyance path, and the light amount adjustment of the light source of the measuring unit of the sheet conveying apparatus in which the shielding unit is positioned between the measurement unit and the conveyance path is executed by a computer. Computer program for
A computer program comprising a procedure for adjusting a light amount of a light source of the measurement unit based on a measurement result of a shielding unit protruding into the measurement region.

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