JP3296766B2 - Sheet processing apparatus and image forming apparatus having the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet processing apparatus having sheet stacking means on which discharged sheets are sequentially stacked, and an image forming apparatus having the sheet processing apparatus.

[0002]

2. Description of the Related Art There is known a sheet processing apparatus in which an upper surface of a sheet stacked on a stacking tray is always at a constant height.

[0003] This device comprises a discharge tray on which discharged sheets are sequentially stacked, lifting means for lifting and lowering the tray, and
An upper surface detection sensor that detects the upper surface of the uppermost sheet among the sheets stacked on the sheet discharge tray, and a control unit that controls the elevating unit based on the detection result.
As the upper surface detection sensor, for example, a light transmission type sensor is used. This sensor is configured such that a light emitting unit and a light receiving unit are respectively disposed on the left and right above the discharge tray, and the optical axis crosses the upper side of the discharge tray in the left-right direction.

As the discharged sheets are stacked on the stacking tray one after another, the height of the uppermost sheet increases. When the uppermost sheet reaches the optical axis, the optical axis is blocked by this sheet. That is, the sensor detects the uppermost sheet. Based on the detection result, the control means controls the elevating means to lower the loading tray.
The amount of lowering of the stacking tray at this time is an amount until the optical axis blocked by the uppermost sheet is restored. By repeating the above-described operation each time a sheet is discharged and stacked on the stacking tray, it is possible to always maintain the highest sheet of the sheets on the stacking tray at a constant height.

[0005] By doing so, the height from the discharge port from which the sheet is discharged to the uppermost sheet, that is, the drop height of the sheet at the time of discharge can be kept constant, so that the sheet can be discharged well. Loading is possible.

[0006]

However, according to the above-mentioned conventional example, there is no problem when the sheets discharged onto the stacking tray are satisfactorily stacked in a plane, but a part of the discharged sheets is not required. The following problems occurred when the cargo was loaded in a raised state.

That is, when a succeeding sheet is discharged and stacked on a preceding sheet that is well stacked in a planar shape, a part of the sheet rises and floats from the preceding sheet. For example, when the leading edge of the succeeding sheet does not reach the leading edge of the preceding sheet, and the trailing edge of the succeeding sheet floats so as to lean against the side wall of the sheet processing apparatus main body (hereinafter, the raised portion is referred to as "deformed" Department "
In other words, the upper surface detection sensor may detect this deformed portion. In this case, the stacking tray is lowered until the deformed portion completely passes through the upper surface detection sensor, and the drop height of the next sheet becomes higher than usual. For this reason, there is a problem that the next sheet is not discharged or stacked properly. Further, when the deformed portion of the sheet is not eliminated even by the lowering of the stacking tray, there is a problem that the deformed portion is bent by the sheet discharged and stacked next.

Accordingly, the present invention is to solve the above-mentioned problem, that is, to perform excellent discharge and stacking of sheets to a sheet stacking means (in the above-described stacking tray), including prevention of bending of a deformed portion of the sheet. It is an object of the present invention to provide a sheet processing apparatus capable of performing the above-described processing and an image forming apparatus including the same.

[0009]

According to a first aspect of the present invention, there is provided a sheet processing apparatus which is supported by a sheet processing apparatus main body so as to be able to move up and down and is discharged from the sheet processing apparatus main body. In a sheet processing apparatus provided with a sheet stacking unit that supports the sheet stacking unit from below and a lifting unit that raises and lowers the sheet stacking unit, and detects an upper surface of a sheet discharged on the sheet stacking unit and outputs a detection signal. Detecting means, and control means for controlling the elevating means so as to lower the sheet stacking means when a detection signal is input from the upper surface detecting means, wherein the controlling means comprises the upper surface detecting means After input of the detection signal from the above, if the input of the detection signal does not disappear even if the sheet stacking means is lowered by a predetermined amount,
Performing a series of correction control such that the sheet stacking means is lowered until the input of the detection signal is stopped, then raised until the detection signal is input, and then lowered until the detection signal is output. And

According to a second aspect of the present invention, in the sheet processing apparatus, the upper surface detecting means is a light transmission type sensor in which an optical axis is formed between a light emitting section and a light receiving section, and the optical axis is shielded. Wherein the detection signal is output, and when the optical axis returns, the output of the detection signal is stopped.

According to a third aspect of the present invention, in the sheet processing apparatus, the sensor is arranged such that an optical axis of the sensor is directed to a left and right direction in a sheet discharging direction above the sheet stacking means. And

According to a fourth aspect of the present invention, in the sheet processing apparatus, the optical axis of the sensor is parallel to a rear edge of a sheet on the sheet stacking means above a base end of the sheet stacking means. A sensor is arranged.

According to a fifth aspect of the present invention, in the sheet processing apparatus, a driving source of the elevating means is disposed on the sheet stacking means side.

According to a sixth aspect of the present invention, in the sheet processing apparatus, a driving source of the lifting / lowering means is disposed on the sheet processing apparatus main body side.

An image forming apparatus according to claim 7, further comprising: an image forming section for forming an image on a sheet; and a sheet processing apparatus for processing a sheet after image formation. Is the claim 1, 2, 3,
A sheet processing apparatus according to 4, 5, or 6.

[Operation] The main operation based on the above configuration is as follows.

The control means detects the sheet stacking means if the input of the detection signal does not stop even if the sheet stacking means is lowered by a predetermined amount after the detection signal is input from the upper surface detecting means. By lowering until there is no input of the signal, then raising it until there is a detection signal, and then performing a series of correction controls such as lowering until there is no detection signal, eliminating the deformed portion of the sheet, The consistency of the sheets on the sheet stacking means can be improved.

[0018]

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

<Embodiment 1> FIG. 21 shows an example of a sheet processing apparatus according to the present invention and an image forming apparatus having the same. The image forming apparatus shown in FIG. 1 is a copying machine having an automatic document feeder.

The image forming apparatus shown in FIG. 21 includes an image forming apparatus main body 300, an automatic document feeder 500, and a sheet processing apparatus 1.

Image forming apparatus main body (hereinafter simply referred to as "apparatus main body")
Reference numeral 300 denotes a platen glass 906 as a document table, a light source 907, a lens system 908, a paper feeding unit 909,
An RD that has an image forming unit 902 and feeds the document D to the platen glass 906 with respect to the apparatus main body 300
An F (automatic document feeder) 500, a sheet processing apparatus 1 for stacking an image-formed sheet P discharged from the apparatus main body 300, and the like are mounted.

A paper supply unit 909 is provided for storing sheets P such as recording paper.
And cassettes 910 and 911 detachably mounted on the apparatus main body 300 and a deck 913 arranged on a pedestal 912. The image forming unit 902 includes a cylindrical photosensitive drum 914 and a developing unit 915, a transfer charger 916, and a separation charger 9 disposed around the photosensitive drum 914.
17, a cleaner 918, and a primary charger 919. On the downstream side of the image forming unit 902, the transport device 92
0, a fixing device 904, a discharge roller pair 399, and the like. In the figure, reference numeral 200 denotes a stack tray (described later) from which the sheet P is discharged, and reference numeral 201 denotes a sample tray (described later).

Next, the operation of the apparatus main body 300 having the above configuration will be described.

When a sheet feed signal is output from a control device (control means) 930 provided on the apparatus main body 300 side, sheets P are fed from the cassettes 910 and 911 or the deck 913. On the other hand, light reflected from the light source 907 on the document D placed on the platen glass 906 is reflected on the surface of the photosensitive drum 914 via the lens system 908. The surface of the photosensitive drum 914 is uniformly charged in advance by a primary charger 919, and an electrostatic latent image is formed by irradiating light. Then, the toner is attached to the electrostatic latent image by a developing device 915. And is developed as a toner image.

The sheet P fed from the sheet feeding unit 909 is
The skew is corrected by the registration rollers 901, and the skew is sent to the image forming unit 902 at the same timing. In the image forming unit 902, the toner image on the photosensitive drum 914 is transferred to the fed sheet P by the transfer charger 916, and the sheet P on which the toner image has been transferred is charged by the separation charger 917. And is separated from the photosensitive drum 914.

Then, the separated sheet P is conveyed to a fixing device 904 by a conveying device 920, where it is heated and
Upon receiving the pressure, the toner image is permanently fixed on the surface. The sheet P on which the toner image is fixed is discharged from the apparatus main body 300 by a discharge roller pair 399.

After an image is formed on the sheet P fed from the sheet feeding unit 909 in this way, the sheet processing apparatus having the sheet punching device 50, a staple unit 100 (described later), etc. It is discharged to 1.

Next, a sheet processing apparatus 1 according to the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a sheet processing apparatus (hereinafter, referred to as “finisher”), and reference numeral 300 denotes an apparatus main body. A detailed description of the apparatus main body 300 and the RDF 500 will be omitted here. 399 is a discharge roller pair arranged on the apparatus main body 300 side, 2 is an entrance roller arranged on the sheet processing apparatus main body side, 3 is a conveying roller, 31 is a paper detection sensor, and 50 is after the conveyed sheet P. A punch unit (sheet punching device) 5 for punching a hole near the end is a large conveying roller, which presses and conveys the sheet P by pressing rollers 12, 13, and 14.

Reference numeral 11 denotes a switching flapper,
Is switched between the non-sort path 21 and the sort path 22. Reference numeral 10 denotes a switching flapper, which switches the transport destination of the sheet P to a sort path 22 and a buffer path 23 for temporarily storing the sheet P. Reference numeral 6 denotes a conveying roller, 130 denotes a processing tray for temporarily accumulating, aligning and stapling the sheets P, and 7 denotes a processing tray 130.
A discharge roller for discharging the sheet P upward, 150 is a swing guide, and 180b is supported by the swing guide 150, and when the swing guide 150 comes to the closed position, a bundle discharge arranged on the processing tray 130 is performed. This is a bundle discharge upper roller for carrying the bundle of sheets P on the processing tray 130 together with the lower roller 180a and discharging the bundle onto the stack tray 200.

Next, the staple unit 100 will be described with reference to FIG. 2 (main cross section), FIG. 3 (view in the direction of arrow a), and FIG. 4 (view in the direction of arrow b).

A stapler 101, which is one of the main components of the staple unit 100, is fixed to a movable table 103 via a holder 102. Rollers 106, 105 are attached to shafts 104, 105 fixed to the moving table 103, respectively.
107 is rotatably assembled, and these rollers 106,
Reference numeral 107 denotes a hole-shaped rail hole 10 opened on the fixing base 108.
8a, 108b, and 108c.

The rollers 106 and 107 are both fixed base 1
Flange 1 having a diameter greater than the width of the rail 08
06a and 107a, while the support rollers 112 are disposed at three places below the moving table 103, so that the moving table 103 supporting the stapler 101 does not come off and the rail holes 108a and 108b , 108c along the fixed base 108. Mobile platform 1
Numeral 03 moves on a fixed table 108 by a roller 109 rotatably provided on the table.

The rail holes 108a, 108b, 10
8c is a front part (lower part in FIG. 3) and a back part (upper part in FIG. 3).
In the above, two rail holes are branched off from each other and become parallel. When the stapler 101 is located at the front side due to such a rail shape, the one roller 106 is fitted to the rail hole 108b side, and the other roller 107 is fitted to the rail hole 108a side to be inclined. .
When the stapler 101 is located at the center, both the rollers 106 and 107 have both rail holes 108.
a to be in a horizontal state.

Further, when the stapler 101 is located on the back side, the one roller 106 is on the rail hole 108a side, and the other roller 107 is on the rail hole 108c side, contrary to the position on the near side. It is fitted and therefore in a state inclined in the opposite direction to the front side.

It should be noted that the two rollers 106 and 107 are two parallel rail holes, that is, the rail holes 108a and 108b, or the rail holes 108a and 108c.
After each is fitted to the position, it moves while maintaining its inclined posture. Then, the action of starting the turning is performed by a cam (not shown).

Next, the moving mechanism of the stapler 101 will be described.

One roller 106 of the above-mentioned movable table 103
Is formed integrally with a pinion gear 106b and a belt pulley 106c, and the pinion gear 106b is connected to a motor M100 fixed from above the moving table 103 via a belt wrapped around the pulley 106c. On the other hand, a rack gear 110 meshing with the above-described pinion gear 106b is fixed to the lower surface of the fixed base 108 along the rail hole 108a, and the forward and reverse rotation of the motor M100 causes the movable base 103 to move together with the stapler 101. It is moved in the front-back direction (vertical direction in FIG. 3).

A stopper falling roller 112 is provided on a shaft 111 extending in the direction of the lower surface of the moving table 103. This is to avoid a collision between a rear end stopper 131 of the processing tray 130 and a stapler 101 described later.
It serves to rotate the rear end stopper 131, and will be described later in detail.

The stapler unit 100 is provided with a sensor for detecting the home position of the stapler 101, and the stapler 101 normally stands by at the home position (the forefront in this embodiment).

Next, the rear end stopper 131 for supporting the rear end of the sheets P stacked on the processing tray 130 will be described.

The rear end stopper 131 is provided on the processing tray 130.
A supporting surface 131a having a surface perpendicular to the stacking surface of the sheet and supporting the rear end of the sheet, a pin 131b for fitting and swinging in a round hole provided in the processing tray 130, and a link to be described later. It has a pin 131c for matching. The link includes a main link 132 having a cam surface 132a against which the roller 112 mounted on the stapler moving table 130 comes into contact and is pressed, a pin 132b disposed at an upper end of the main link 132, and a rear end stopper 131. It is constituted by a connection link 133 connecting the pin 131c.

The main link 132 swings about a shaft 134 fixed to a frame (not shown) as a fulcrum. The lower end of the main link 132 is the main link 1
Tension spring 135 for urging the C. 32 clockwise in FIG.
Is provided, and the main link 132 is provided with an abutment plate 136.
Normally, the rear end stopper 1
Numeral 31 keeps a vertical position with respect to the processing tray 130.

When the moving table 103 moves, the cam surface 132a of the main link 132 connected to the rear end stopper 131, which has an interference relationship with the stapler 101, is moved to the moving table 1
03 is pushed down, the rear end stopper 131 is pulled by the connecting link 133, and is rotated to a position where it does not interfere with the stapler 101. A plurality (three in the present embodiment) of the falling rollers 112 is provided so that the rear end stopper 131 maintains this avoidance position while the stapler 101 is moving.

A staple stopper 113 (two-dot chain line) having a support surface having the same shape as the rear end stopper 131 is attached to both side surfaces of the holder 102 supporting the staple 101, so that the stapler 101 is in a horizontal state. The staple stopper 113 can support the rear end of the sheet even if the rear end stopper 131 is pressed at the (center).

Next, the processing tray unit 129 will be described with reference to FIGS.

The processing tray unit 129 is provided in the main body 3 of the apparatus.
Conveying unit for conveying the sheet P from 00 and the processing tray 13
Stack tray 2 that receives and stores the bundle processed in step 0
It is arranged between 00 and 00.

The processing tray unit 129 includes a processing tray 130, a rear end stopper 131,
0, a swing guide 150, a pull-in paddle (hereinafter simply referred to as a “paddle”) 160, a retreat tray 170, and a bundle discharge roller pair 180.

The processing tray 130 is an inclined tray with the downstream side (the left side in the figure) upward and the upstream side (the right side in the figure) downward. The rear end stopper 131 is provided at the lower end. Mated. The sheet P discharged by the discharge roller 7 of the transport unit slides on the processing tray 130 by its own weight and the action of a paddle 160 described later until the rear end of the sheet P contacts the rear end stopper 131.

Also, at the upper end of the processing tray 130,
A bundle discharge lower roller 180a is attached to the bundle discharge lower roller 180a, and a bundle discharge upper roller 180b that comes into contact with the bundle discharge lower roller 180a is attached to a swing guide 150 described later.
It can rotate forward and backward in response to the drive from.

Next, the aligning means 140 will be described with reference to FIG.

The alignment members (alignment walls) 141 and 142 as the alignment means 140 are disposed on the near side and the back side, respectively, and are configured to be independently movable in the front-rear direction. Both the front alignment member 141 and the rear alignment member 142 stand on the processing tray 130,
A support surface that bends vertically from the alignment surfaces 141a and 142a that press the sheet-side end surface and supports the lower surface of the sheet P;
The gears 141b and 142b extend in the front-rear direction in parallel with the processing tray 130, and are provided with rack gears. The two alignment members 141 and 142 are supported by opened guides extending in the front-rear direction of the processing tray 130, and are assembled so that the alignment surface is on the upper surface of the processing tray 130 and the gear portion is on the lower surface of the processing tray 130. Have been.

Then, each rack gear portion 141b, 1
42b, separate pinion gears 143, 144 are engaged, and these pinion gears 143, 144 are pulleys,
The motors M141 and M142 are connected via belts, and the alignment members 141 and 142 move in the front-rear direction by the forward and reverse rotation of the motors M141 and M142. Each of the alignment members 141 and 142 is provided with a sensor (not shown) for detecting the home position, and normally waits at the home position by the detection of the sensor.

In this embodiment, the home position of the alignment member 141 on the near side is set to the foremost part, and the home position of the alignment member 142 on the back side is set to the deepest part.

Next, the swing guide 150 will be described.

The swing guide 150 supports the above-mentioned bundle discharge upper roller 180b on the downstream side (left side in FIG. 5).
On the upstream side (right in FIG. 5), a swing fulcrum shaft 151 is provided. The swing guide 150 is normally in an open state (the bundle discharge roller pair 180 is separated) when the sheet P is discharged one by one to the processing tray 130, and discharges the sheet P onto the processing tray 130. It does not interfere with the stacking, dropping, and aligning operations, and when the bundle is discharged from the processing tray 130 to the stack tray 200, it moves to the closed state (the bundle discharge roller pair 180 abuts).

The rotary cam 152 is disposed at a position corresponding to the side surface of the swing guide 150. When the rotary cam 152 rotates and pushes up the guide side surface, the swing guide 150 rotates the shaft 151.
The pivoting cam 152 pivots from this state, and closes when it separates from the side of the pivoting guide. The rotary drive of the rotary cam 152 is performed by a motor M150 connected via a drive system (not shown).

The swing guide 150 has a home position when opened, and is provided with a sensor (not shown) for detecting the home position.

Next, the pull-in paddle 160 will be described.

The pull-in paddle 160 includes a paddle shaft 161.
, And the paddle shaft 161 is rotatably supported by front and rear side plates. The paddle shaft 161 is
The motor M160 is connected to the motor M160 and rotates counterclockwise in FIG. 5 when driven by the motor M160. The length of the pull-in paddle 160 is set slightly longer than the distance to the processing tray 130, and
0 is the home position by the discharge roller 7 and the processing tray 1
The sheet P is set at a position (solid line in the drawing) where the sheet P is not brought into contact with the sheet P discharged to the sheet 30. In this state, when the discharge of the sheet P is completed and the sheet P lands on the processing tray 130, the draw-in paddle 160 rotates counterclockwise under the driving of the motor M160, and the sheet P
Pull in until it touches 1. Thereafter, after waiting for a predetermined time, the pull-in paddle 160 stops at the home position, and prepares for discharging the next sheet P.

Next, the haunting tray 170 will be described with reference to FIG. 5 and FIG.

The retracting tray 170 is provided with the bundle discharging lower roller 18.
0a, and advances and retreats in the sheet conveying direction (the direction of the arrow x) while substantially following the inclination of the processing tray 130. In the protruding state, the tip of the retracting tray 170 overlaps with the stack tray 200 side (two-dot chain line in FIG. 5), and in the retracting state, the tip retreats to the right side of the bundle discharge roller pair 180 (solid line in FIG. 5). ). The leading end position in the protruding state is set so that the center of gravity of the sheet P discharged onto the processing tray 130 does not exceed this leading end.

The retreat tray 170 is supported by 22 rails 172 fixed to the frame 171 and is movable in the sheet discharging direction. Further, since the rotating link 173 rotates about the shaft 174 and is engaged with the groove provided on the lower surface of the retractable tray 170, the retractable tray 170 advances and retreats as described above by one rotation of the rotating link 173. Things.

The driving of the rotating link 173 is performed by a motor M170 via a driving mechanism (not shown). And the home position of the haunting tray 170 is
The evacuation position is set to a retreat position (solid line in FIG. 5), and the position is detected by a sensor (not shown).

Next, a stack tray (sheet stacking means)
The sample tray 200 (sheet stacking unit) 201 will be described with reference to FIGS. It should be noted that both trays are collectively referred to as “tray 200, 201”.

These two trays 200 and 201 can be properly used depending on the situation,
0 is selected when receiving a copy output, a printer output, etc., and the upper sample tray 201 is used when receiving a sample output, an interrupt output, an output when a stack tray overflows, a function sorting output, a job mixed output, etc. Will be selected.

Each of these two trays 200 and 201 has a motor 202 so that both can run independently in the vertical direction.
The rack 210 is also attached to a rack 210 which also serves as a roller receiver attached vertically. Further, the configuration of the trays 200 and 201 in which the play in the front and back directions of the tray is regulated by the regulating member 215 is such that the stepping motor 202 is attached to the tray base plate 211, and the pulley press-fitted on the motor shaft includes: The drive is transmitted to the pulley 203 by the timing belt 212.

Shaft 213 connected to pulley 203 by a parallel pin
Is a ratchet 20 which is connected to the shaft 213 by a parallel pin.
5 and drive the ratchet 205 to the idler gear 20.
4 is urged by a spring 206. Idler gear 204
Is connected to the gear 207 to transmit driving, and the gear 207 is connected to the gear 209 to transmit driving. Another gear 207 is mounted via a shaft 208 to drive the trays 200 and 201 both in the front and rear directions. These two gears 207 are connected to a rack 210 via a gear 209. The trays 200 and 201 have two rollers 21 on one side.
4 is fixed by being accommodated in a roller receiver 210 also serving as a rack. Each of the trays 200 and 201 constitutes a tray unit by integrating the above-described motor 202, idler gear 204, a base plate 211 for supporting these, a sheet support plate (not shown) mounted on the base plate 211, and the like. I have.

In order to prevent the tray drive system from being damaged by foreign matter when the tray descends, the above-mentioned ratchet 205 is moved only in the direction in which the trays 200 and 201 are lifted.
It is designed to slip over by pushing 6. When the idling is performed, the sensor S201 for immediately stopping the driving of the motor 202 detects the slit incorporated in the idler gear 204. This sensor S201
Is normally used as a step-out detection. When the swing guide 150 is in the closed position, it is a part of the loading wall of the trays 200 and 201 so that the processing tray 130 having the closed portion can cross the opening of the processing tray 130 up and down.
Sensor detects the closed position of swing guide 150 (not shown)
You can move only when you are.

Next, a sensor S202 is an area detecting sensor, and includes a sensor from an upper limit sensor 203a (see FIG. 9) for stopping the trays 200 and 201 from rising too much to a stack tray paper surface detecting sensor (upper surface detecting means) S205. Detects area flags. The sensor S203a for detecting the position of the 1000 sample trays is disposed at a position corresponding to 1000 sheets from the non-sorted sheet surface detection sensor (upper surface detecting means) S204, and limits the stacking amount of the sample tray 201 by the height. is there.

In step S203c, the sample tray 20
Numeral 1 is for limiting the stacking amount when receiving the sheets P from the processing tray 130 by the height, and is also arranged at a position corresponding to 1000 sheets from the paper surface detection sensor S204. S203d is for limiting the stacking amount when the stack tray 200 receives the sheet P from the processing tray 130 by the height, and the sheet surface detection sensors S205 to S205d
It is arranged at a position corresponding to 00 sheets. S203e is a lower limit sensor for preventing the stack tray 200 from lowering too much. Among the above-mentioned sensors, a paper surface detection sensor S204,
Only S205 is a transmission sensor at the front and rear. Further, each of the trays 200 and 201 has a sheet presence / absence detection sensor S20.
6 are arranged.

As a method of detecting the paper surface, the tray 20 is located below the paper surface detection sensors S204 and S205.
0 and 201 are lifted, and the state where these stacked sheets and the P block the optical axis of the sheet surface detection sensors S204 and S205 is an initial state.
The operation of lowering the optical axis in steps 204 and S205 until the optical axis appears, and then raising the optical axis again until the optical axis is interrupted is repeated.

Next, the flow of the sheet P when the user specifies the non-sort mode will be described.

When the user wants to specify the non-sort mode on the operation unit (not shown) of the apparatus main body 300, as shown in FIG. 10, the entrance roller 2, the transport roller 3, and the large transport roller 5 rotate, and The sheet P conveyed from the main body 300 is conveyed. The flapper 11 moves to a position shown in the figure by the action of a solenoid (not shown), and conveys the sheet P to the non-sort path 21. When the sensor 33 detects the rear end of the sheet P, the discharge roller 9 rotates at a speed suitable for stacking, and discharges the sheet P to the sample tray 201.

Next, the operation of the sheet P when the user specifies the staple sort mode will be described.

As shown in FIG. 11, the entrance roller 2, the conveying roller 3, and the large conveying roller 5 rotate, and
The sheet P conveyed from is transported. Flapper 1
0 and 11 are stopped at the positions shown in the figure. The sheet P passes through the sort path 22 and is discharged from the processing tray 1 by the discharge roller 7.
It is discharged on 30. At this time, the haunting tray 170
Since the sheet P is located at the protruding position, the tip of the sheet P on the processing tray 130 after discharge is prevented from sagging or returning poorly, and the alignment of the sheet on the processing tray 130 is improved.

The discharged sheet P starts to move to the rear end stopper 131 by its own weight. In addition, the pull-in paddle 160 stopped at the home position rotates counterclockwise by the drive of the motor M160, and The movement of the sheet P on the tray 130 is promoted. When the rear end of the sheet P is securely brought into contact with the rear end stopper 131 and stopped, the rotation of the pull-in paddle 160 is also stopped, and the alignment members 141 and 142 align the discharged sheet P. The alignment operation of the sheet P will be described later.

When all the sheets P of the first copy are in the processing tray 13
When the sheet is ejected onto the upper roller 180b, the swing guide 150 descends as shown in FIG.
Is on the sheet bundle, and the stapler 101 staples the sheet bundle.

On the other hand, the sheet P ₁ discharged from the apparatus main body 300 during that time is wound around the large conveying roller 5 by switching the flapper 10 as shown in FIG.
It stops when it has advanced a predetermined distance from the sensor 32. Next sheet P ₂ is When you reach a predetermined distance from the sheet detecting sensor 31,
As shown in FIG. 13, the large conveying roller 5 is rotated, from the first sheet P ₁ is towards the second sheet P ₂ superposed to the predetermined distance ahead, transport large as shown in FIG. 14 It winds around the roller 5 and stops at a predetermined distance. On the other hand, the sheet bundle on the processing tray 130 is discharged onto the stack tray 200 as shown in FIG.

However, at this time, the haunting tray 170
In order to drop the sheet bundle on the stack tray 200,
Before the sheet bundle passes through the bundle discharge roller pair 180, it moves to the home position. As shown in FIG. 14, when the third sheet P ₃ reaches a predetermined position, the large conveying roller 5 rotates, and the sheets P ₃ are shifted by a predetermined distance and overlapped. As shown in FIG. The three sheets P are switched and conveyed to the sort path 22.

As shown in FIG. 16, while the swinging guide 150 is lowered, three sheets P are received by the lower bundle discharge roller 180a and the upper bundle discharge roller 180b, and the trailing edge of the sheets P as shown in FIG. Has passed through the discharge roller 7, the lower bundle discharge roller 180a and the upper bundle discharge roller 180b rotate in reverse,
Before the rear end of the sheet P comes into contact with the rear end stopper 131,
As shown in FIG. 18A, the swing guide 150 is raised, and the upper bundle discharge roller 180b is separated from the sheet surface.
The fourth and subsequent sheets P are discharged onto the processing tray 130 through the sort path 22 similarly to the operation of the first copy. 3
After the first copy, the same operation as that of the second copy is performed, and the sheets are stacked on the stack tray 200 for the set number of copies, and the process ends.

The plurality of sheets P (sheets P ₁ , P
₂ and P ₃ ), each sheet P is offset in the transport direction. That is, the sheet P ₂ is offset relative to the seat P ₁ only on the downstream side b (see FIG. 18 (b)), further, the sheet P ₃ is offset b on the downstream side with respect to the sheet P _2.

The offset amount of the sheet P and the swing guide 15
The rising timing of 0 is related to the settling time of the sheet P by the return speed of the bundle discharge upper roller 180b, that is, is determined by the processing capacity of the apparatus main body 300. In the present embodiment, the sheet conveyance speed is 750 mm / s, offset amount (b = 20 mm), bundle discharge roller return speed 500 mm
In / s, the separation timing of the bundle discharge upper roller 180b is a rear end of the sheet P ₁ is, from the rear end stopper 131 4
The timing is set to a position (value a) within 0 mm.

Next, the sort mode will be described.

The user sets the document D on the RDF 500, specifies a sort mode on an operation unit (not shown), and turns on a start key (not shown). As in the staple sort mode, the entrance roller 2 and the transport roller 3
9, the sheet P is stacked on the processing tray 130. The aligning means 140 stacks a small number of sheets on the processing tray 130 while aligning the sheets P on the processing tray 130, and then the swing guide 150 descends as shown in FIG. Are conveyed in a bundle.

Next, the fed sheet P passes over the flapper 10, is wound around the large conveying roller 5 in the same manner as the operation described in the staple sort mode, and is discharged to the processing tray 130 after the bundle discharge is completed. You. The number of the minority bundles to be discharged is desirably 20 or less by experiments. The number of sheets is set so as to satisfy the number of original sheets ≧ the number of sheets to be discharged ≦ 20 sheets. Therefore, if the number of sheets to be discharged in a bundle is set to five when a program is set, when the number of documents is four, the sheets are discharged in a bundle of four sheets. If the number of originals is 5 or more, for example, 14 sheets, they are divided into 5 + 5 + 4, aligned, and discharged in a bundle.

When all the bundles of the first set have been discharged, the alignment member 141 on the front side moves together with the alignment member 142 on the back side to offset the alignment position of the second copy with respect to the alignment position of the first copy.

The second copy is aligned at an offset position, and a small number of sheets are discharged in bundles, similarly to the first copy. When the second copy is completed, the alignment member 141 on the near side and the alignment member 142 on the back side return to the position where the first copy is aligned, and align the third copy. In this way, the bundles are discharged onto the stack tray 200 while being shifted in the left-right direction toward the unloading direction, and the discharge of all the set number of copies is completed.

Next, the movement of the stack tray 200 and the sample tray 201 will be described (FIGS. 8 and 9). Each of the trays 200 and 201 usually waits at the position of each paper surface detection sensor before the operation starts.

In the above description, it is the stack tray 200 that normally stacks the copy or printer output, and receives the bundle processed by the stapler 101 and the like and the bundle that is unbound and discharged little by little. 2,000 sheets can be stacked at the maximum, and this is detected by the sensor 203d.

At this time, if the output of the copy printer is still continued, the stack tray 200 is further lowered from the sensor S203d by a position corresponding to 1000 sheets (S203).
d 'position). Subsequently, the sample tray 201 is lowered to the sheet surface detection sensor S205 for the stack tray 200, and the sample tray 201 starts receiving the sheet P again. At this time, a maximum of 1000 sample trays can be stacked, and the sensor 203c detects that.

Next, after the job of 2000 sheets or less is completed, when the next job is started without interrupting the sheet P on the stack tray 200 or when interrupting during the current job, the processing operation is performed. Can't, but sheet P
Can be stacked on the sample tray 201 from the non-sort path 21.

According to the normal state, the mode for outputting to the sample tray 201 using the non-sort path 21 is as follows.
For example, when sample tray output is set in function sorting.

Next, with reference to FIGS. 22, 23, 24, and 25, a characteristic portion of the present invention will be described in detail. In the present invention, when a deformed portion such as leaning occurs on the sheets P stacked on the stack tray 200, the stack tray 200 is raised and lowered so as to correct the deformed portion.

As shown in FIGS. 22 and 23, the paper surface detection sensor S205 is located near the lower bundle discharge roller 180a in the
0 is located above the base end 200a. The paper surface detection sensor S205 includes a light emitting unit 205a and a light receiving unit 2 mounted above the left and right of the stack tray 200.
05b, and an optical axis L is formed between them. The optical axis L is parallel to the trailing edge of the sheet P in a state of being properly stacked on the stack tray 200.
The light emitting unit 205a and the light receiving unit 205b described above are arranged. The paper surface detection sensor S205 issues a detection signal when the optical axis L is blocked, and outputs the detection signal to the control device 930.
The control device 930 drives the motor 202 of the stack tray 200 to move the stack tray 200 up and down as described later.

As shown in FIG. 24A, the tip 200
b, the loading surface 2 having the base end 200a inclined downward.
At 00c, the sheet P is discharged from the bundle discharge roller pair 180 of the sheet processing apparatus 1 and stacked. At this time, the sheet P
Is discharged onto the stacking surface 200c, descends along the stacking surface 200a, and the rear end thereof is the outer wall 1a of the sheet processing apparatus 1.
And stop. That is, the sheets P that are satisfactorily stacked on the stacking surface 200c or on the already stacked sheets P are stacked with their rear ends in contact with the outer wall 1a. The sheet P is stacked, and the sheet P
When the light shields the optical axis L of the paper surface detection sensor S205, the paper surface detection sensor S205 issues a detection signal to the control device 930, whereby the control device 930 drives the motor 202 to lower the stack tray 200. The lowering amount of the stack tray 200 at this time is until the optical axis L of the paper surface detection sensor S205 returns. Therefore,
In principle, when sheets P continue to be favorably stacked on the stack tray 200 in a planar manner, the stack tray 2
00, the sheet P is lowered by the amount corresponding to the thickness of the sheet P every time the sheets P are stacked. The above is the operation when the sheets P are satisfactorily stacked.

Next, a case where a deformed portion Pa such as leaning occurs on the stacked sheets P will be described.

As shown in FIG. 24A, when a deformed portion Pa occurs in the stacked sheets P, the optical axis L is blocked by the deformed portion Pa. Note that, since the drawing shows a cross section, the optical axis L is shown to pass below the deformed portion Pa, but in reality, the height of the deformed portion Pa differs between the left and right of the sheet P. In many cases, the optical axis is blocked by the deformed portion Pa.

When the optical axis L is blocked, the stack tray 200 is lowered as shown in FIG. At this time, if the optical axis L does not return even if the stack tray 200 is lowered by a predetermined amount h (for example, 10 mm) or more, the lowering is continued until the optical axis L returns, as shown in FIG. . After the optical axis L returns, the stack tray 200 is raised until the optical axis L is shielded, as shown in FIG. Then, when the optical axis L is shielded, as shown in (e), the stack tray 200 is returned until the optical axis L returns.
Is lowered. By such a series of correction controls (a) to (e), the deformed portion Pa of the sheet P is eliminated, and
The upper surface of the sheet P is arranged at a normal position. Further, it is possible to prevent the deformed portion Pa from being bent due to the subsequent discharge of the subsequent sheet P onto the deformed portion Pa. The above-described correction control according to the present invention includes:
In particular, this is effective when a plurality of sheets P are discharged in a bundle or when stapled sheets are discharged.

FIG. 25 shows a flowchart of the above-described series of correction control, but the description thereof is omitted because it is the same as that described above.

Although the motor 202 as a driving string of the stack tray 200 is provided on the stack tray 200 in the above-described embodiment, it may be provided on the sheet processing apparatus main body 1A instead.

[0102]

As described above, according to the present invention,
Good discharge and stacking of sheets to the sheet stacking means can be performed, including prevention of bending of the deformed portion of the sheet.

[Brief description of the drawings]

FIG. 1 is a front view showing the overall configuration of a sheet processing apparatus according to the present invention.

FIG. 2 is a front view of a stapler and a processing tray.

FIG. 3 is a plan view of a stapler moving mechanism similarly as viewed in the direction of arrow a in FIG. 2;

FIG. 4 is a rear view of the stapler similarly viewed in the direction of arrow b in FIG. 2;

FIG. 5 is a vertical sectional front view of the swing guide and the processing tray.

FIG. 6 is a plan view of a processing tray and an alignment wall moving mechanism.

FIG. 7 is a plan view of the haunting tray.

FIG. 8 is a plan view of the stack tray moving mechanism.

FIG. 9 is a sensor arrangement diagram around the stack tray.

FIG. 10 is an operation diagram of the sheet processing apparatus in the non-sort mode.

FIG. 11 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIG. 12 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIG. 13 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIG. 14 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIG. 15 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIG. 16 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIG. 17 is an operation diagram of the sheet processing apparatus in the staple sort mode.

FIGS. 18A and 18B are operation diagrams of the sheet processing apparatus in the staple sort mode.

FIG. 19 is an operation diagram of the sheet processing apparatus in the sort mode.

FIG. 20 is an operation diagram of the sheet processing apparatus in the sort mode.

FIG. 21 is a front view of an image forming apparatus to which the sheet processing apparatus according to the invention can be applied.

FIG. 22 is a side view of a paper surface detection sensor and a stack tray.

FIG. 23 is a front view of a paper surface detection sensor and a stack tray.

FIGS. 24A to 24E are operation explanatory diagrams showing correction control of sheets stacked on a stack tray.

FIG. 25 is a flowchart illustrating correction control of sheets stacked on a stack tray.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 sheet processing apparatus 1A sheet processing apparatus main body 1a outer wall 200 sheet stacking means (stack tray) 200a base end of sheet stacking means (base end of stack tray) 201 sheet stacking means (sample tray) 202 elevating means (drive source) , Motor) 205a light emitting unit 205b light receiving unit 209 elevating means (gear) 210 elevating means (rack) 902 image forming unit 930 control means (control device) L optical axis P sheet S204, S205 upper surface detecting means (paper surface detecting sensor)

Claims (7)

(57) [Claims] A sheet stacking means supported by the sheet processing apparatus main body so as to be able to move up and down and supporting a sheet discharged from the sheet processing apparatus main body from below; and an elevating means for raising and lowering the sheet stacking means. In the sheet processing apparatus, an upper surface detecting unit that detects an upper surface of a sheet discharged onto the sheet stacking unit and outputs a detection signal; and when the detection signal is input from the upper surface detecting unit, the sheet stacking unit. And control means for controlling the elevating means so as to lower the sheet stacking means.After receiving a detection signal from the upper surface detecting means, the control means may lower the sheet stacking means by a predetermined amount. If the input of the detection signal does not stop, the sheet stacking means is lowered until the input of the detection signal stops, and then the detection signal is output. In raised, subsequently, the detection signal is a series of corrective control such lowering until no, it sheet processing apparatus according to claim. 2. The upper surface detecting means is a light transmission type sensor in which an optical axis is formed between a light emitting unit and a light receiving unit, and the detection signal is output when the optical axis is shielded, The sheet processing apparatus according to claim 1, wherein the detection signal is not output when the optical axis returns. 3. The sheet according to claim 2, wherein the sensor is arranged so that an optical axis of the sensor is directed to a left and right direction in a sheet discharging direction above the sheet stacking unit. Processing equipment. 4. The sensor is arranged such that an optical axis of the sensor is parallel to a trailing edge of a sheet on the sheet stacking means above a base end of the sheet stacking means. The sheet processing apparatus according to claim 3, wherein 5. The sheet processing apparatus according to claim 1, wherein a driving source of the lifting / lowering means is arranged on the sheet stacking means side. 6. The sheet processing apparatus according to claim 1, wherein a drive source of the lifting / lowering means is disposed on the sheet processing apparatus main body side. 7. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a sheet processing apparatus that processes a sheet after image formation, wherein the sheet processing apparatus is An image forming apparatus according to any one of claims 3, 4, 5, and 6.