JP2006193264A - Sheet processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet processing device capable of stacking a paper sheet bundle on a stack tray with high accuracy. <P>SOLUTION: The sheet processing device comprises a paper sheet discharge means to discharge paper sheets stacked on a stack tray, a paper sheet position recognition means to recognize the position of the paper sheets during the discharge, a control unit to calculate the required correction of the recognized paper sheet position to the matching reference position, a position correction means to move the paper sheet position to the matching reference position according to the required correction, and a plurality of pressing means to press the discharged paper sheets against the stack tray and regulate the sheets. When the paper sheets are stacked, a part of the paper sheets on the stack tray are pressed by at least one pressing means. One pressing means presses on end of the paper sheet on the tray while the paper sheet discharge means restricts the paper sheets, and after the paper sheet discharge means discharges a rear end of the paper sheet, the other pressing means presses the other end of the paper sheet on the tray. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet processing apparatus, and more particularly to a sheet processing apparatus that is mounted on an image forming apparatus and performs sheet material alignment and stack processing.

  In a conventional processing apparatus (hereinafter, “finisher”), in the sort mode in which sheets are sorted without binding the sheets on one stack tray, the sheets are discharged and stacked one by one on the stack tray. The stack tray is offset forward and backward for each part of the sheet bundle to sort the bundle. In this method, the sheets are discharged one by one without being aligned, so that there is a disadvantage that the sheet alignment is poor.

  In addition, since the stack tray is offset forward and backward, a stack tray capable of stacking a large number of sheets requires a motor having a large transmission torque, resulting in a high cost of the apparatus. In order to solve these drawbacks, a method has been proposed in which a small number of sheets are once aligned in a processing tray and then bundled and discharged onto a stack tray (see Patent Document 1).

Japanese Patent No. 2051685 JP-A-10-194568

  However, in the above conventional example, after the sheet is discharged, the sheet and the sheet bundle are thrown into the air without being restrained by the discharge roller, fall on the tray by gravity, and are stacked according to the inclination of the tray. There is a drawback in that it is difficult to make the sheet drop position constant due to variations in discharge speed due to air resistance and paper thickness differences, resulting in variations in sheet alignment.

  An object of the present invention is to provide a sheet processing apparatus capable of stacking a bundle of sheets on a stack tray with high accuracy.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a sheet discharge means for discharging sheets stacked on a stacking tray, a sheet position recognition means for recognizing the position of a sheet being discharged, and a recognized sheet position. A control unit that calculates a necessary correction amount up to the alignment reference position, a position correction unit that moves the paper position to the alignment reference position according to the required correction amount, and a plurality of units that press and regulate discharged paper onto the stacking tray. The sheet processing apparatus includes the pressing means.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, at least one pressing means presses a part of the paper on the stacking tray during the paper stacking operation.

  The invention according to claim 3 is the invention according to claim 2, wherein one pressing means presses one end of the paper on the tray when the paper discharge means is restraining the paper, and then the paper discharge means is the paper After the trailing end is discharged, the other pressing means presses the other end of the sheet on the tray.

  The invention according to claim 4 is the invention according to claim 3, characterized in that the one pressing means presses the leading edge in the sheet conveying direction, and the other pressing means presses the trailing edge in the sheet conveying direction.

  The invention according to claim 5 is the invention according to claim 3, wherein the one pressing means presses the left end in the paper transport direction, and the other pressing means presses the right end in the paper transport direction. do.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the sheet position recognizing means comprises a camera unit having an image sensor.

  According to a seventh aspect of the present invention, in the first aspect of the present invention, the paper position recognition means comprises a line sensor.

  The invention according to claim 8 is the invention according to claim 1, wherein the position correcting means is composed of two rollers arranged on the same axis having an independent drive system, and also serves as means for discharging the paper onto the stacking tray. It is characterized by.

  According to the present invention, the sheets on the tray are always gripped while the sheets are stacked while the position of the sheet is recognized and the position of the sheet is controlled by the skew roller which is a sheet position correcting unit. Misalignment of the sheet bundle due to entry can be prevented, and stacking accuracy can be increased. Further, since the stacking and alignment is performed without depending on the gravity, it is possible to reduce the influence due to the difference in the frictional force, which is different from the paper type and the paper size, and causes the deterioration of the consistency.

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

<Embodiment 1>
FIG. 1 shows an example of an image forming apparatus main body provided with a sheet processing apparatus according to the present invention.

  The image forming apparatus main body (copier main body) 300 includes a document reading unit 600 including an automatic document feeder 500, a paper feeding unit 909, an image forming unit 902, and the like. The image forming unit 902 includes a cylindrical photosensitive drum 914, a developing unit 915 around the photosensitive drum 914, a transfer charger 916, a separation charger 917, a cleaner 918, a primary charger 919, and the like. Further, on the downstream side of the image forming unit 902, a conveying device 920, a fixing device 904, a discharge roller pair 399, and the like are disposed.

  The operation of the image forming apparatus main body will be described. When a paper feed signal is output from a control device (not shown) provided on the apparatus main body 300 side, the sheet P is fed from the paper feed unit 909. On the other hand, image information read by the document reading unit 600 is scanned on the photosensitive drum 914 by the laser scanner 700. The photosensitive drum 914 is charged in advance by a primary charger 919, and an electrostatic latent image is formed by irradiation with laser light, and then the electrostatic latent image is developed by a developing device 915 to form a toner image. The The sheet P fed from the sheet feeding unit 909 is corrected for skew by the registration roller 901, and further fed to the transfer unit 916 of the image forming unit 902 at a proper timing. In the transfer unit 916, the toner image is transferred to the sheet P and sent to the fixing device 904 through the conveying device 920, and the toner image is fixed on the sheet P. The sheet P is sent to the sheet processing apparatus by the paper discharge roller 399.

  Next, the stack tray will be described with reference to FIGS.

  Wires 101 are attached and fixed to the end portions 100 a and 100 b of the tray 100. The wire 101 is wound around the pulley 102, and its end is connected to the take-up pulley 103. A rotary shaft 104 of the take-up pulley 103 is connected to a drive system and is driven to rotate by a motor 105. As the motor 105 rotates, the connected wire 101 is wound up and the tray 100 is raised.

  Further, when the motor 105 is rotated in the reverse direction, the wire 101 is fed out and the tray 100 is lowered. Normally, the tray 100 is at the position shown in the figure (solid line), and this position is the home position. As the sheet P is stacked on the tray 101, the tray is lowered by detecting the upper surface of the sheet, which will be described later, and a lower limit sensor (not shown) is operated at the lowest position (broken line) to stop the supply of a new sheet P. Then, a display prompting the operator to take out the stacked sheet material is displayed.

  Next, the configuration of the imaging unit will be described (FIG. 11).

  The imaging unit is disposed on the upper side of the sheet front end press 301. The leading edge position of the sheet material is detected in the area indicated by the arrow A by the CCD camera 201 provided in the imaging unit, and is output as a recognition pattern to a later-described sheet position control unit. The position of the camera 301 is arranged at a position where all the sheet sizes to be used can be photographed, or the position is moved according to the size, or the position of the sheet is set using a plurality of cameras 201a and 201b as shown in FIG. You may shoot. In the present embodiment, one camera is installed at the center, and is arranged so that the corners at the front end of the paper can be recognized.

  Next, the skew roller will be described with reference to FIGS.

  The skew roller 401 is disposed coaxially in the front and rear, and includes an independent drive system in the front and rear. The drive system is composed of a pulse motor 402, and the speed can be slightly changed at any time during conveyance. Here, when different rotation speeds v1 and v2 (v1> v2) are given to the front and rear rollers, the conveyed sheet P is conveyed while rotating according to the speed difference. The sheet is conveyed while controlling the sheet position by a control signal from a sheet position control unit described later, and the sheet is conveyed to the target position. The roller pair 403 on the upstream side of the skew roller has a separating means, and when the sheet is rotated by the skew roller, the upstream roller is separated to prevent the rotation of the sheet.

  Next, sheet pressing will be described with reference to FIG.

  The sheet pressers 301 and 302 are arranged at the front end position and the rear end position of the sheet P, and fix the position of the sheet P on the tray 100 by pressing the sheet P on the tray 100 from above. Switching between fixing and releasing is performed by an actuator 305 provided independently for each sheet presser. In particular, a brush 304 in which flexible fibers such as polyamide fibers are planted in a certain oblique direction is attached to a part of the pressing surface 303 of the sheet pressing member 302 on the rear end side. When the sheet presser presses the sheet P, the sheet P is pulled in a slanting direction by the brush 304, the slackness T is removed, and the positional accuracy is improved. When the paper is pressed down, it will be more effective if it is vibrated several times up and down.

  Next, the stapler will be described with reference to FIG.

  Reference numeral 501 denotes a stapler upper unit, and 502 a stapler lower unit. The stapler unit is configured to be movable by a rail 503 and a rack and pinion. While the sheets are being stacked, the sheet is retracted to the retracted position. When the stacking is completed, the staple unit is moved to the staple position while the sheet is held by the sheet presser fixing the sheet bundle. When the staple position is reached, the stapler is pushed down and stapled while the sheet is held down. More accurate stapling is performed by finely adjusting the position of the stapler according to the position of the sheet captured by the imaging unit. Reference numeral 504 denotes a transport gripper for transporting the bundle after stapling to another tray, which is operated after releasing the sheet pressers at the leading and trailing ends that hold the sheets, and transports the sheet bundle from the tray.

  Next, the flow of the sheet and the operation of the entire sheet processing apparatus will be described with reference to FIG.

  When the user designates the non-sort mode with the operation unit (not shown) of the image forming apparatus main body, the sheet is conveyed by rotating the roller upstream from the skew roller as shown in FIG. At this time, the front and rear skew rollers are moved straight without giving a rotation difference (FIG. 8a).

  When the leading edge of the sheet reaches the arrow A area (FIG. 11) on the tray (FIG. 8c), the leading edge position and orientation of the sheet captured by the imaging unit are recognized (FIG. 8d), and the positional information is controlled by the sheet position. And shift amounts ΔX, ΔY, Δθ from the target reference position are calculated (FIG. 4). The number of rotations applied to the skew roller is calculated according to the amount of deviation, and the skew roller is driven (FIG. 8e). The control does not give a simple constant speed, but the sheet is conveyed in two stages, such as changing the orientation of the sheet as shown in FIG.

  Pattern recognition at the image pickup unit is performed a plurality of times within the A region, and the skew roller is driven and controlled each time, and feedback control is applied to enable more accurate alignment. Further, since the actual paper position is recognized, it is possible to prevent the position from being shifted due to the influence of friction, paper thickness, and the like. When the paper reaches the reference position, the leading edge paper press 301 is operated (FIG. 8g), and the sheet P is pressed onto the tray 100. The skew roller 401 is rotated as it is until the trailing edge of the sheet is discharged. The trailing edge of the sheet is caused to flow to the right side of the tray by the skew roller 401, and the trailing edge of the sheet falls on the tray (dashed line in FIG. 9) (FIG. 8h).

  When the sheet falls on the tray, the trailing edge paper presser 302 is operated to fix the sheet on the tray (FIG. 8i). When pressing, as described above, the sheet is loosened by the pulling effect of the brush by pumping several times, and the cause of variation in the sheet position is removed.

  Next, if the second sheet starts to be conveyed by the skew roller, the leading edge sheet press 301 is released before the leading edge of the sheet reaches the reference position. Similarly, when the sheet P reaches the reference position, the front end sheet presser 301 is operated to fix the sheet P on the tray 100. Before the skew roller 401 discharges the trailing edge of the sheet, the trailing edge sheet presser 302 is opened to prepare for the next fixing. By repeating the above, a non-sorted sheet bundle is produced.

  Next, the staple sort mode will be described.

  In the staple mode, bundles are stacked on the tray 100 as in the non-sort mode. When the predetermined number of sheets is loaded, the stapler unit 500 moves and staples to a predetermined position. After the end of the stapling, the sheet pressers 301 and 302 at the leading edge and the trailing edge are opened, and the sheet is conveyed onto the separate tray 150 by the conveyance gripper 504, and preparation for stacking the next sheet is performed.

  Next, the sort mode will be described with reference to FIG.

  In the sort mode, the sheet conveyance and gripper operations are the same, but the sheet bundle must be offset and stacked. Accordingly, there are two loading reference positions, and the loading is performed by switching the reference position for each part. Further, the offset amount can be set to an arbitrary amount within the photographing range of the camera, and it is also possible to offset and stack at three or more positions.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIG. 12, FIG. 15 and FIG.

  In the first embodiment, the sheet pressers 301 and 302 for fixing the sheets on the stacking tray are configured to press the leading end and the trailing end in the sheet transport direction. However, in the present embodiment, the leading ends in the sheet transport direction. The paper pressers 351 and 352 are arranged so as to fix the left end and the right end of the paper. Tapered portions are provided at the tips of the sheet pressers 351 and 352, and even when the sheets are discharged while holding the sheets on the tray, they do not interfere with the loading on the arm sections of the sheet pressers. For example, when the first sheet is ejected, the sheet is moved to the target position by the position correcting unit, and then the near-side corner is pressed by the near-side sheet presser 351.

  Next, when the sheet is pressed onto the tray by the back side sheet presser 352, the near side sheet presser 351 rotates away from the tray and retracts from the tray. The next sheet enters into the retracted position and aligns with the front side corner as a reference. At this time, the paper presser 352 on the rear end side presses the front paper, but the paper discharged by the taper at the tip of the arm portion gets on and does not interfere with the alignment at the front corner.

  FIG. 17 (left view of FIG. 12) shows a state in which the front side paper presser 351 is retracted, the back side paper presser 352 presses the front paper, and the next paper is on top. Thus, even if the sheet presser is disposed only on the front end side, the sheets can be stacked in the same manner as in the first embodiment by alternately pressing the sheets and fixing the sheets on the tray.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described with reference to FIG.

  In the first embodiment, a camera equipped with a CCD is used as the paper position recognizing means. However, in this embodiment, line sensors 371 and 372 are provided before and after the skew roller 401 to detect the skew and misalignment of the paper. Recognize the position of the paper.

  First, the upstream line sensor 372 recognizes the leading edge of the sheet P conveyed by the conveying roller 403, and detects the skew amount and the deviation amount in the left-right registration direction. Based on this data, a deviation amount to the target paper position on the tray is predicted, and the skew roller is controlled. The paper position control method is performed by turning the paper by giving a rotational difference to the front and rear skew rollers as in the first embodiment.

  Further correction is applied by the downstream line sensor 371 to control the paper position more precisely. The paper position is recognized upstream of the method of recognizing the paper on the tray of the first embodiment using the camera, and the paper is moved, but the accuracy is lowered, but the paper position on the tray is predicted with low cost and space saving. Can be corrected. The effect of always restraining and aligning the sheet is the same as in the first embodiment.

1 is a cross-sectional view of a sheet processing apparatus and an image forming apparatus to which the present invention is applied. It is sectional drawing of the sheet processing apparatus to which this invention is applied. 1 is a top sectional view of a sheet processing apparatus to which the present invention is applied. FIG. 6 is an explanatory diagram of a state of positional deviation between a skew roller and a sheet. It is a figure explaining sheet press. It is a figure explaining a stapler. It is explanatory drawing at the time of arrange | positioning two cameras. It is processing flow explanatory drawing. It is explanatory drawing of sheet | seat behavior. It is a figure explaining the shift at the time of sort mode. It is operation | movement explanatory drawing. FIG. 10 is an explanatory diagram when the sheet presser is in the sheet conveyance direction, at the left end and the right end. It is a layout diagram of a line sensor. It is a diagram for explaining the actual movement of the paper. FIG. 13 is a top view of FIG. 12. It is a left view of FIG. It is explanatory drawing of a prior art.

Explanation of symbols

100 Processing tray 201 Camera 301 Paper presser (tip)
302 Paper presser (rear edge)
401 Skew roller 500 Stapler unit

Claims (8)

  A paper discharge means for discharging the paper stacked on the stacking tray, a paper position recognition means for recognizing the position of the paper being discharged, and a control unit for calculating a necessary correction amount to the alignment reference position of the recognized paper position; A sheet processing apparatus comprising: a position correcting unit that moves a paper position to an alignment reference position according to a necessary correction amount; and a plurality of pressing units that press and regulate discharged paper onto a stacking tray.   2. The sheet processing apparatus according to claim 1, wherein at least one pressing unit presses a part of the paper on the stacking tray during the paper stacking operation.   One pressing means presses one end of the paper on the tray when the paper discharging means restrains the paper, and then the other pressing means discharges the paper on the tray after the paper discharging means discharges the rear edge of the paper. The sheet processing apparatus according to claim 2, wherein the other end of the sheet is pressed.   4. The sheet processing apparatus according to claim 3, wherein the one pressing unit presses the front end in the sheet conveying direction, and the other pressing unit presses the rear end in the sheet conveying direction.   4. The sheet processing apparatus according to claim 3, wherein the one pressing unit presses the left end in the sheet conveying direction, and the other pressing unit presses the right end in the sheet conveying direction.   2. A sheet processing apparatus according to claim 1, wherein the sheet position recognizing means comprises a camera unit having an image pickup device.   2. A sheet processing apparatus according to claim 1, wherein the sheet position recognition means comprises a line sensor.   2. A sheet processing apparatus according to claim 1, wherein the position correcting means comprises two coaxially arranged rollers having independent drive systems, and also serves as means for discharging the paper onto the stacking tray.

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