JP2009161329A - Paper discharge device, image forming device and post-processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper discharge device for executing a shifting process while accurately aligning papers without lowering processing efficiency. <P>SOLUTION: The paper discharge device having an aligning member for aligning the papers by lowering from a retreat position to an aligning position is provided with a sensor for detecting height of an upper face of a paper bundle loaded on a paper discharge tray and changes retreat height of the aligning member corresponding to height of an upper part of the paper bundle detected by the sensor. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a sheet discharge apparatus having a shift processing function, an image forming apparatus including the sheet discharge apparatus, and a post-processing apparatus including the sheet discharge apparatus.

  A sheet processing apparatus that processes a large amount of sheets is often provided with a sheet discharge apparatus having a shift function that changes the position for each set number of sheets and loads the sheets on a discharge tray.

  In order to realize a shift processing mechanism having a high alignment function, a sheet discharge device having a shift function requires that each of the sheet bundles sorted by the shift process be highly aligned. Development is underway.

  The cause of the paper alignment on the paper discharge tray is paper curl.

In Patent Document 1, the height of the upper surface of the stacked paper is detected at a plurality of positions on the paper discharge tray, and when the height within a predetermined range is detected, paper discharge is prohibited, thereby causing the paper curl. Emission is prevented from being performed in a state of poor alignment.
JP 2002-226133 A

  As in Japanese Patent Application Laid-Open No. 2004-133620, although the operation of the apparatus is stopped when the state of the upper surface of the stacked paper bundle on the paper discharge tray is not normal due to paper curl, the alignment accuracy can be improved, but the paper processing efficiency Therefore, the method of Patent Document 1 is not always effective.

  That is, in order to increase the alignment accuracy, the criteria for determining whether or not the upper surface state is normal for loading should be strict, but if strict, the apparatus will stop frequently and the efficiency will decrease.

  On the other hand, if the criterion is relaxed, the efficiency is improved, but the accuracy of matching is lowered.

  The present invention aims to solve such problems.

  That is, an object of the present invention is to provide a paper discharge device that can perform shift processing on paper discharged with high precision alignment without reducing the operation efficiency of the device.

  It is another object of the present invention to provide an image forming apparatus and a post-processing apparatus provided with such a paper discharge device.

The above object is achieved by the following sheet discharge device, image forming apparatus, and post-processing device of the present invention.
1.
A paper output tray for stacking the discharged paper,
A pair of alignment members provided above the discharge tray;
First moving means for moving the aligning member in a horizontal direction perpendicular to the sheet conveying and discharging direction;
A second moving means for moving the alignment member up and down;
Control means for controlling the first and second moving means;
A step of aligning sheets by setting the alignment member at a lower alignment height and moving one of the alignment members in the horizontal direction;
B step of moving the alignment member to the upper retracted height after the a step;
C step of shifting the alignment position of the alignment member by moving the alignment member in the horizontal direction at the retracted height; and
The control means repeatedly executes a shift process including a step d of lowering the alignment member to the alignment height,
In the paper discharge device that alternately performs alignment of one side edge of the paper by one of the alignment members and alignment of the other side edge of the paper by the other one of the alignment members,
Detecting means for detecting the height of the upper surface of the stack of sheets stacked on the discharge tray;
The control means changes the retract height of the alignment member in the step b by controlling the second moving means based on the height of the upper surface of the sheet bundle detected by the detecting means. Paper discharge device characterized by.
2.
2. The paper discharge apparatus according to claim 1, wherein the detection unit includes a sensor that detects the height of the alignment member and the alignment member placed on the sheet bundle.
3.
3. The paper discharge apparatus according to claim 1 or 2, wherein the control unit performs non-shift alignment by repeating an alignment process in which both of the alignment members are reciprocally moved in the horizontal direction.
4).
4. The sheet discharge according to claim 3, wherein the control unit performs the non-shift alignment when the height of the upper surface of the sheet bundle detected by the detection unit is equal to or greater than a predetermined first threshold value. apparatus.
5.
The control unit generates a warning signal when the height of the upper surface of the sheet bundle detected by the detection unit is equal to or greater than a predetermined second threshold value. The paper discharge device described in 1.
6).
6. The paper discharge apparatus according to any one of 1 to 5, wherein the second moving unit moves each of the alignment members independently.
7).
An image forming apparatus comprising the paper discharge device according to any one of the above items 1 to 6.
8).
A post-processing device comprising the paper discharge device according to any one of 1 to 6 above.

  According to the present invention, the height of the upper surface of the sheet bundle stacked on the paper discharge tray is detected, and the retracting height of the alignment member is changed according to the detected height. Even when the height of the upper surface changes, the alignment member operates according to the changed height, and the alignment of the sheets is performed.

  Therefore, the alignment state does not collapse due to curling, and the efficiency is prevented from being lowered due to frequent operation stoppage due to curling.

  Next, although this invention is demonstrated based on embodiment, this invention is not limited to this embodiment.

[Image forming system]
FIG. 1 is an overall configuration diagram of an image forming system including an image forming apparatus A, an automatic document feeder DF, a post-processing apparatus FS, and a large-capacity paper feeder LT.

  The illustrated image forming apparatus A includes an image reading unit 1, an image processing unit 2, an image writing unit 3, an image forming unit 4, a paper transport unit, and a fixing device 6.

  The image forming unit 4 includes a photosensitive drum 4A, a charging unit 4B, a developing unit 4C, a transfer unit 4D, a separating unit 4E, a cleaning unit 4F, and the like.

  The paper transport unit includes a paper feed cassette 5A, a first paper feed unit 5B, a second paper feed unit 5C, a first transport unit 5D, a second transport unit (automatic duplex copy transport unit) 5E, and a paper discharge unit 5F. .

  A post-processing device FS is connected to the paper discharge unit 5F side of the left side of the image forming apparatus A shown in the figure.

  A document d placed on the document table of the automatic document feeder DF is read by the CCD image sensor 1A after an image on one side or both sides of the document d is read by the optical system of the image reading unit 1.

  The analog signal photoelectrically converted by the CCD image sensor 1A is subjected to processing such as analog processing, A / D conversion, shading correction, and image compression processing in the image processing unit 2, and is stored in an image memory (not shown). .

  In the image writing unit 3, output light from the semiconductor laser is irradiated onto the photosensitive drum 4 </ b> A of the image forming unit 4 to form a latent image. In the image forming unit 4, processes such as charging, exposure, development, transfer, separation, and cleaning are performed. An image is transferred by the transfer means 4D to the recording paper K fed from the paper feed cassette 5A and the large capacity paper feeder LT by the first paper feed unit 5B. The recording sheet K carrying the image is fixed by the fixing device 6 and sent from the paper discharge unit 5F to the post-processing device FS.

  The recording paper K that has been subjected to the fixing process is also sent to the second transport unit 5E by the transport path switching plate 5G, is re-feeded, and is discharged from the paper discharge unit 5F after the rear surface image is formed in the image forming unit 4. .

  The large-capacity paper feeding device LT includes a paper stacking unit 11, a first paper feeding unit 12, and the like. The large-capacity paper feeding device LT stacks and stores a large capacity recording paper K and sends the recording paper K to the image forming apparatus A.

  The post-processing device FS is a post-processing device that performs a folding process and a shift process on the recording paper K and the additional paper F and discharges them to the fixed paper discharge tray 28 or the lift paper discharge tray 29.

  The post-processing device FS includes a paper carry-in unit 21, a horizontal conveyance unit 22, a lower conveyance unit 23, a folding processing unit 24, an additional paper conveyance unit 25, and an upper conveyance unit 26.

  The recording paper K discharged from the image forming apparatus A passes through the horizontal transport unit 22 and is discharged through the upper transport unit 26 to the fixed paper discharge tray 28 or passes through the horizontal transport unit 22 and is moved up and down. Or the paper passes through the lower conveyance unit 23, is folded in the folding processing unit 24, and then is ejected to the lift sheet discharge tray 29.

  The additional paper feeding unit 27 stores additional paper F such as intersheet paper and cover paper, and the additional paper F is added to the recording paper from the image forming apparatus A, and is moved up and down through the conveying unit. It is discharged to the paper tray 29.

  The recording paper K is discharged onto the fixed paper discharge tray 28 in an image forming mode in which a small number of images are formed and no folding process or shift process is performed.

  The recording paper K and the additional paper F are discharged to the elevating paper discharge tray 29 in the folding processing mode, the large image forming mode for forming a large number of images, the folding processing mode, and the shift paper discharging mode.

  As is well known, the folding processing section 24 has a function of performing various folding processes such as bi-folding and various tri-folding, and the folded recording paper K and additional paper F are transported upward and then horizontally. The paper is discharged to a lift paper discharge tray 29 by a paper discharge roller 30 provided in the transport unit 22.

  The paper discharge device 100 including the lift paper discharge tray 29 has a shift paper discharge function.

  Next, the paper discharge device 100 having the shift paper discharge function will be described.

  FIG. 2 is a front sectional view of the paper discharge device 100.

  As described above, the recording paper K and the additional paper F are discharged to the paper discharge tray 29. In the following description, the recording paper K and the additional paper F are collectively referred to as a paper S.

  As described above, the paper S discharged by the paper discharge roller 30 is discharged to the paper discharge tray 29, but FIG. 2 shows the paper S stacked on the paper discharge tray 29.

  The upper surface of the paper S is detected by a sensor 105 made of a photoelectric sensor, and the paper discharge tray 29 moves up and down so that the upper surface of the paper S is always at a constant height. Such vertical movement of the paper discharge tray 29 is performed by driving a motor (not shown) controlled by the control means.

  Above the paper discharge tray 29, a pair of plate-like alignment members 101 and 102 for aligning the paper S in a horizontal direction (hereinafter referred to as the width direction) perpendicular to the transport and discharge direction are arranged side by side in the width direction.

  The alignment members 101 and 102 are rotatable about the rotation axis AX, and are set at an alignment position indicated by a solid line, a first retracted position indicated by a dotted line, and a second retracted position indicated by a dotted line.

  The alignment members 101 and 102 are rotated by driving of the motor 104 as the second moving means, and are set to the alignment position, the first retracted position, and the second retracted position.

  At the alignment position indicated by the solid line, the alignment members 101 and 102 are placed on the paper S under their own weight.

  As will be described later, the alignment members 101 and 102 move in the width direction of the sheet S. This movement is performed by driving a motor 103 as a first moving unit, and the motor is driven by a transmission mechanism using a belt and a pulley. The driving force 103 is transmitted to the alignment members 101 and 102.

  The rotation positions of the alignment members 101 and 102, particularly the alignment positions and the first and second retracted positions are set based on signals output from the sensor 106 that is a photoelectric sensor.

  FIG. 3 shows a mechanism constituting detection means for detecting the height of the alignment members 101 and 102.

  The detecting means for detecting the height of the upper surface of the sheet bundle includes alignment members 101 and 102, an encoder 107, and a sensor 106.

  An encoder 107 is fixed to the rotation axis AX of the alignment members 101 and 102, and the sensor 106 detects the rotation position of the encoder 107.

  FIG. 4 is a block diagram of a control system that performs shift discharge control in the sheet discharge apparatus 100.

  In the figure, 103 and 104 are motors for driving the alignment members 101 and 102 as described above, and 106 is a sensor for detecting the rotational position of the alignment members 101 and 102.

  Reference numeral 111 denotes a paper sensor provided in the paper carry-in portion 21 in FIG.

  The control unit 110 performs shift control based on detection signals from the sensor 106 and the paper sensor 111.

  Next, the shift control will be described with reference to FIG.

  In FIG. 5, the directions indicated by arrows V1, V3, and V5 are the width directions perpendicular to the transporting and discharging direction of the paper S.

  On the discharge tray 29, as shown in step SP1, a number of sheet bundles SS1 constituting one unit of the set shift are accumulated.

  In SP1, the alignment members 101 and 102 are set to an alignment height which is a lower position indicated by a solid line in FIG.

  The alignment member 102 set at the alignment height reciprocates in the width direction as indicated by the arrow V1 to align the sheets S. The sheet alignment is performed by moving the alignment member 102 each time one sheet S is discharged.

  When the sheet bundle SS1 reaches the set number by the signal from the sheet sensor 111, the alignment members 101 and 102 are both raised as indicated by the arrow V2 in step SP2.

  The movement distance indicated by the arrow V2 is such a distance that the lower ends of the alignment members 101 and 102 are separated from the upper surface of the sheet bundle SS1.

  In step SP2, the alignment members 101 and 102 are set at a retracted height away from the upper surface of the sheet bundle SS1.

  Note that the retracted height of the alignment members 101 and 102 shown in step SP2 corresponds to the second retracted position in FIG.

  The second retracted positions indicated by 101B and 102B in FIG. 2 are lower than the first retracted positions (indicated by 101A and 102A) where the alignment members 101 and 102 are located when the paper discharge device 100 is in the stopped state.

  After the alignment members 101 and 102 are raised, they move horizontally to the right (in the width direction) as indicated by an arrow V3.

  The movement distance indicated by the arrow V3 is a distance corresponding to the shift amount.

  Next, as indicated by step SP3, the alignment members 101 and 102 are lowered as indicated by the arrow V4.

  As shown in step SP4, the alignment members 101 and 102 are lowered to the alignment height where the lower ends thereof are in contact with the upper surface of the sheet bundle SS1.

  In step SP4, the alignment member 101 reciprocates in the width direction as indicated by the arrow V1 to align the sheets.

  Step SP5 is the same stage as step SP2, and after the alignment members 101 and 102 are lifted as indicated by arrow V2, they are horizontally moved to the left as indicated by arrow V5.

  In step SP6 following step SP5, the alignment position where the alignment members 101 and 102 are lowered and shifted as indicated by arrow V4 is set.

  In subsequent step SP7, the aligning member 102 reciprocates as indicated by the arrow V1 to align the sheets S.

  By the alignment process in steps SP1 to SP7, the sheet bundles SS1, SS2, and SS3 subjected to the shift process are formed.

  In step SP2 of FIG. 5, the alignment member 102 is above the sheet bundles SS1 and SS2 and is at a retracted height away from the uppermost surface of the sheet bundle in step SP5.

  In steps SP2 and SP5, when the paper S is curled, the uppermost surfaces of the paper bundles SS1, SS2, SS3, etc. may be above the specified position.

  FIG. 6 shows such a state.

  FIG. 6A shows a state in which the uppermost sheet S of the sheet bundle SS is lifted by curling, and FIG. 6B shows a state in which an intermediate sheet S in the sheet bundle SS is lifted by curling.

  As described above, the uppermost surface of the sheet bundle SS is maintained constant by the control of the paper discharge tray 29 using the sensor 105, and in the case of a normal sheet S with no sheet curl, a constant height is maintained. That's it.

  When the sheet S is curled, the height of the top surface of the sheet bundle SS varies as shown in FIG.

  6A and 6B, due to the curling of the paper S, the lower end of the alignment member 101 at the retracted height comes into contact with the upper surface of the paper bundle SS. Although not shown, the sheet S may also come into contact with the alignment member 102 at the retracted height.

  Therefore, when the alignment members 101 and 102 move in the width direction (directions indicated by V3 and V4 in FIG. 5) in the state shown in FIG. 6, the sheet S also moves and the alignment state may be lost.

  In order to avoid such a problem, the retracting height of the alignment members 101 and 102 may be set always high. However, the alignment members 101 and 102 move between the alignment position and the second retracted position. The time required for the movement, that is, the time required for movement indicated by arrows V2 and V4 in FIG.

  Such a problem has been solved by detecting the height of the upper surface of the sheet bundle SS and performing control to change the retreat height based on the detection result.

  In the present embodiment, the height of the upper surface of the sheet bundle SS is detected by a signal from a sensor 106 that detects the rotational positions of the alignment members 101 and 102.

  That is, information on the angles of the alignment members 101 and 102 placed on the upper surface of the sheet bundle SS is obtained from the signal of the sensor 106.

  The control unit 110 controls the motor 104 based on the detection signal of the sensor 106 that detects the angle of the alignment members 101 and 102 in step SP4 in FIG. 5, and the arrow V2 of the alignment members 101 and 102 in step SP5 in FIG. Controls the distance when ascending as indicated by.

  That is, when the height of the sheet bundle SS1 is high, the control unit 110 increases the ascending distance of the alignment members 101 and 102 indicated by the arrow V2 in step SP5.

  By such control, as shown in FIG. 6, the alignment member 101 is prevented from coming into contact with the paper, and smooth alignment is performed.

  Note that the distance at the time of ascending indicated by the arrow V2 in step SP2 in FIG. 5 is set to the maximum distance that does not cause contact even when the paper is curled, thereby aligning the member indicated by the arrow V3 in step SP2. It is possible to prevent paper misalignment during movement of 101 and 102.

  Even if such control in step SP2 is performed, it is limited to the first sheet bundle in the shift sheet discharge, and therefore the sheet discharge efficiency is hardly lowered.

  In FIG. 5, as shown in steps SP4 and SP7, the alignment member that is not placed on the sheet bundle SS1 or SS2, that is, the alignment member 101 in SP4 and the alignment member 102 in SP7 are reciprocated to perform alignment. However, the alignment can be performed by reciprocating the alignment member placed on the sheet bundle SS.

  FIG. 7 shows such an alignment effect.

  The alignment member 101 placed on the sheet bundle SS1 is reciprocated as indicated by an arrow V1 to perform alignment.

  The sheet alignment shown in FIG. 7 is preferably performed for large size sheets.

  Although it may be difficult to secure a space for the reciprocating movement of the alignment member in a large-size sheet, the alignment shown in FIG. 7 solves such a problem.

  In FIG. 5, the alignment member 101 and the alignment member 102 move differently in the width direction, but move in the same direction in the vertical direction.

  However, the vertical drive of the alignment member 101 and the vertical drive of the alignment member 102 may be performed independently to cause them to move differently.

  In some cases, the height of the upper surface of the sheet bundle detected by the alignment member 101 is different from the height of the upper surface of the sheet bundle detected by the alignment member 102.

  Therefore, when the height of the upper surface of the sheet bundle detected by the alignment members 101 and 102 is different, the upward movement distance indicated by V2 of the alignment members 101 and 102 in step SP5 in FIG. Thus, high-precision matching is performed even for non-uniform curls.

  When the fluctuation of the uppermost surface of the sheet bundle SS as shown in FIG. 6 is further large, the above-described control, that is, the alignment by controlling the retracted height of the alignment members 101 and 102 becomes difficult. Consistency may be reduced.

  In such a case, it is preferable to stop the shift process and perform non-shift matching.

  FIG. 8 shows non-shift matching processing without shift processing.

  Each time the sheet S is discharged to the up-and-down discharge tray 29, the alignment members 101 and 102 both reciprocate in the width direction as indicated by the arrow V1, and sheet alignment is performed, thereby forming an aligned sheet bundle SS. Is done.

  In the alignment shown in FIG. 8, since the alignment members 101 and 102 do not move above the sheet bundle SS, even when the sheet is curled, the alignment is not sufficient, and the paper is not discharged smoothly. Will not occur.

  When the curl of the paper is further large and the height of the paper surface detected by the sensor 106 is significant, it is preferable to display a warning signal and stop the paper discharge conveyance.

  In the embodiment shown in FIGS. 1 and 2, a paper discharge device having a shift paper discharge function is provided in the post-processing device FS. However, the paper discharge device described above is used as a paper discharge device of the image forming apparatus. It is also possible to provide in the part.

1 is a diagram illustrating an overall configuration of an image forming system including a paper discharge device according to an embodiment of the present invention. It is a front sectional view of the paper discharge device concerning an embodiment of the invention. It is a figure which shows the mechanism which detects the height of an alignment member. It is a block diagram of the control system which performs shift control. It is a flowchart of shift control. FIG. 6 is a diagram illustrating a state in which the upper surface of a sheet bundle is raised by curling. It is a figure which shows the example of a matching effect | action. It is a figure which shows non-shift matching.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Paper discharge apparatus 101,102 Alignment member 103,104 Motor 106 Sensor 110 Control means

Claims (8)

A paper output tray for stacking the discharged paper,
A pair of alignment members provided above the discharge tray;
First moving means for moving the aligning member in a horizontal direction perpendicular to the sheet conveying and discharging direction;
A second moving means for moving the alignment member up and down;
Control means for controlling the first and second moving means;
A step of aligning sheets by setting the alignment member at a lower alignment height and moving one of the alignment members in the horizontal direction;
B step of moving the alignment member to the upper retracted height after the a step;
C step of shifting the alignment position of the alignment member by moving the alignment member in the horizontal direction at the retracted height;
The control means repeatedly executes a shift process including a step d of lowering the alignment member to the alignment height,
In the paper discharge device that alternately performs alignment of one side edge of the paper by one of the alignment members and alignment of the other side edge of the paper by the other one of the alignment members,
Detecting means for detecting the height of the upper surface of the stack of sheets stacked on the discharge tray;
The control means changes the retract height of the alignment member in the step b by controlling the second moving means based on the height of the upper surface of the sheet bundle detected by the detecting means. Paper discharge device characterized by. The paper discharge device according to claim 1, wherein the detection unit includes a sensor that detects the height of the alignment member and the alignment member placed on the sheet bundle. 3. The paper discharge apparatus according to claim 1, wherein the control unit performs non-shift alignment by repeating an alignment process of reciprocally moving both of the alignment members in the horizontal direction. 4. The sheet according to claim 3, wherein the control unit performs the non-shift alignment when a height of an upper surface of the sheet bundle detected by the detection unit is equal to or greater than a predetermined first threshold value. Discharging device. The control unit generates a warning signal when the height of the upper surface of the sheet bundle detected by the detection unit is equal to or greater than a predetermined second threshold value. The paper discharge device according to the item. The paper discharge device according to claim 1, wherein the second moving unit moves each of the alignment members independently. An image forming apparatus comprising the paper discharge device according to claim 1. A post-processing device comprising the paper discharge device according to claim 1.

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