JPH11199114A - Sheet treatment device, and image forming device equipped with the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the discharge and accumulation failure of sheets, when the sheets accumulated on a stack tray are drawn. SOLUTION: When sheets P on a stack tray 200 are bundledly drawn to lower the position of the upper surface of the uppermost sheet P to form (return) optical axes L1 and L2 , the stack tray 200 is elevated to shade the second optical axis L2 by the sheets P accumulated through the stack tray 200. Consequently the uppermost sheet P on the stack may 200 can be arranged in the vicinity of the first optical axis L1 , resultantly to make the dropping height of the sheet P at the time of discharge adequate, thereby properly discharging and accumulating successive sheets P onto the uppermost sheet upper surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet processing apparatus having a paper surface detection sensor, and more particularly, for example, a sheet processing apparatus having sheet stacking means for sequentially stacking discharged sheets, and the sheet processing apparatus. The present invention relates to an image forming apparatus provided with the device.

[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-described conventional example, when the sheets discharged onto the stacking tray are pulled out in a bundle, the position of the uppermost sheet on the stacking tray is lowered, and the position at the time of discharging is lowered. There is a possibility that the drop height of the sheet is increased, resulting in sheet discharge failure and stacking failure.

Accordingly, the present invention is to solve the above-mentioned problem, that is, to prevent a sheet ejection failure and a loading failure when a sheet on a sheet loading means (in the above-described loading tray) is pulled out. It is an object of the present invention to provide a sheet processing apparatus and an image forming apparatus having the same.

[0008]

In order to achieve the above-mentioned object, a sheet processing apparatus according to the present invention comprises a sheet stacking means which is supported so as to be able to move up and down and stacks discharged sheets; Lifting and lowering means, a first sensor for detecting the uppermost position of the sheet bundle on the sheet stacking means and moving the sheet stacking means by a predetermined amount via the lifting and lowering means, A second sensor that detects that a part of the sheet bundle has been removed and moves the sheet stacking unit via the elevating unit to return the sheet stacking unit to a proper sheet discharge position.

More specifically, the first and second sensors are light transmission type sensors having a light emitting unit and a light receiving unit, and the light emitting unit and the light receiving unit of the first sensor are formed of a sheet. An optical axis substantially parallel to the stacking surface of the sheet bundle is formed, and the light emitting unit and the light receiving unit of the second sensor form an optical axis crossing the stacking surface of the sheet bundle.

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

When the sheet on the sheet stacking means is pulled out and the position of the upper surface of the uppermost sheet is lowered, the second sensor detects this and the sheet stacking means is moved to the first position by the sheet stacked thereon. The optical axis of the first sensor is raised until it is shielded, and then lowered until the optical axis of the first sensor is transmitted. Thus, the uppermost sheet of the sheets on the sheet stacking means can be arranged near the optical axis of the first sensor, so that the sheet can be properly dropped at the time of ejection, and Discharge and stacking of sheets on the upper surface of the upper sheet can be performed satisfactorily.

[0012]

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

<First Embodiment> 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.

An 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 sheet feeding 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 paper feed signal is output from a control device (control means) 930 provided on the apparatus main body 300, sheets P are fed from the cassettes 910, 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,
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 punching device 50 (FIG. 1) and the staple unit 10 described below are used.
The sheet is discharged to the sheet processing apparatus 1 having 0 (described later) or the like.

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, which is a sheet P
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 section), FIG. 3 (a view in the direction of arrow a), and FIG. 4 (a 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 moving 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.

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.

The two rollers 106 and 107 are parallel to each other in two 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).

Further, 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 around a shaft 134 fixed to a frame (not shown). 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 movable 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 movable 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.

On both sides of the holder 102 supporting the staple 101, staple stoppers 113 (two-dot chain lines) having the same support surface as the rear end stopper 131 are attached, 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.
The sheet P is transported between the conveying units 2, 3, 5, and 7 and the stack tray 200 that receives and stores the bundle processed by the processing tray 130.

The processing tray unit 129 includes the processing tray 130, the rear end stopper 131, and the aligning means 14.
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 (left in the figure) upward and the upstream side (right 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.

The upper end of the processing tray 130 has
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 serving as the alignment means 140 are provided 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 at the forefront, and the home position of the alignment member 142 on the back side is set at the deepest.

Next, the swing guide 150 will be described.

The swing guide 150 supports the above 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 is rotated and pushes up the guide side surface, the swing guide 150 is rotated by 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 in an open state, 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 retreat tray 170 overlaps the stack tray 200 side (two-dot chain line in FIG. 5), and in the retracted 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 rotation link 173 is driven by a motor M170 via a drive 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 are properly used depending on the situation, and the stack tray
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 move 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.

A shaft 213 connected to the 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-described ratchet 205 is used 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 (FIG. 8) is an area detecting sensor, and is changed from an upper limit sensor S203a (see FIG. 9) for stopping the trays 200 and 201 from rising too much to a stack tray paper surface detecting sensor (lower limit detecting sensor). ) S20
The flag of the area up to 3e is detected. The sensor S203b for detecting the position of 1000 sheets of the sample tray 201 is
Non-sort paper surface detection sensor (upper surface detection sensor) S20
It is arranged at a position corresponding to 4 to 1000 sheets, and is used to limit the stacking amount of the sample tray 201 by height.

In step S203c, the sample tray 20
Numeral 1 is for limiting the stacking amount when receiving the sheet 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 S205. 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 for detecting the paper surface, the tray 20 is positioned below the paper surface detection sensors S204 and S205.
0 and 201 are raised, the stacked sheets P block the optical axes of the paper surface detection sensors S204 and S205, and the tray is lowered until the optical axes are transmitted. Sensor S204, S2
The lowering operation is repeated until the optical axis 05 appears.

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

When the user designates 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 conveying roller 3, and the large conveying roller 5 rotate, and the apparatus rotates. 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 retracting 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.

The sheets of the first copy are all processed 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 is
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 swing 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 end 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 relates to the stabilization time of the sheet P (the time from when the trailing edge of the sheet passes through the roller 7 to when it reaches the trailing edge aligning means) due to the return speed of the bundle discharge upper roller 180b, that is, the apparatus. Determined by the processing capacity of the main body 300, and in this embodiment, the sheet conveying speed 750
mm / s, the offset amount (b = 20 mm), and the bundle discharge roller return speed 500 mm / s, the bundle discharge upper roller 180
separation timing of b, the trailing edge of the sheet P ₁ has been set from the rear end stopper 131 to timing positions (value of a) within 40 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 that the number of original sheets ≧ the number of sheets to be discharged ≦ 20 sheets is satisfied. 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. Number of documents is 5
In the case of more than one sheet, for example, in the case of 14 sheets, they are divided into 5 sheets + 5 sheets + 4 sheets, aligned, and discharged as 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 the offset position, and a small number of sheets are discharged in bundles as in 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 the printer output, and receives the bundle processed by the above 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 continues, 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, as a mode to be output to the sample tray 201 using the non-sort path 21, output of a sample without processing only one copy or sample tray output by function sorting is set. And so on.

Next, the characteristic portions of the present invention will be described in detail with reference to FIGS. In the present invention,
When the sheet P on the stack tray 200 is pulled out, the stack tray 200 is raised to arrange the uppermost sheet P at a suitable position.

As shown in FIG. 22, the first sheet surface detection sensor S205 is located near the lower bundle discharge roller 180a (see FIG. 1) in the sheet processing apparatus main body 1A and above the base end 200a of the stack tray 200. Are located in The paper surface detection sensor S205 is the stack tray 200
Light emitting unit 205 mounted above each of the left and right
and a a and the light receiving portion 205b, the optical axis (the first optical axis) L ₁ is formed between them. The optical axis L ₁ is as parallel to the trailing edge of the sheet P in the state of being satisfactorily stacked on the stack tray 200, the above-described light emitting portion 205a
And a light receiving unit 205b. Also, the second paper surface detection sensor S207 is the same as the paper surface detection sensor S205 described above.
And it has the same light transmission sensor, to form a second optical axis L ₂ between the light emitting portion 207a and the light receiving portion 207b. The light emitting unit 207a of the second paper surface detection sensor S207 is
In the vicinity of the paper surface detection sensor S205a.
These may be arranged so as to be adjacent to each other,
Further, they may be integrated and configured integrally. The light receiving unit 207b of the second paper surface detection sensor S207 is disposed slightly below the light receiving unit 205b of the first paper surface detection sensor S205. That is, the optical axis L ₁ of the first sheet sensor S205 is different as is set parallel to the trailing edge of the sheet P on the stack tray 200, the optical axis of the second sheet sensor S207 L ₂ Is the first paper surface detection sensor S2
It is set to have an appropriate angle 05 with respect to the optical axis L _1. The paper surface detection sensors S205 and S207 generate a detection signal when these optical axes L ₁ and L ₂ are shielded, and input this detection signal to the control device 930. The control device 930 drives the motor 202 of the stack tray 200. Then, the stack tray 200 is moved up and down as described later. In the present invention, the first paper surface detection sensor S20
5, when the optical axis L ₁ is shielded by the sheet P stacked on the stack tray 200, the optical axis L ₁ is used when lowering the stack tray 200 to return, while the second sheet sensor S207, for example the sheet P on the stack tray 200 is withdrawn in a bundle when the optical axis L ₂ has returned to raise the stack tray 200 to the optical axis L ₁ is interrupted, then the light Axis L ₁
Is used to lower when the light is transmitted.

Usually, the optical axis L ₁ is in a transmitting state,
When a sheet is placed on the stack tray 200 (e.g., once a sheet is removed and a sheet is placed after the stack tray 200 detects the paper surface, etc.), the optical axis L ₁ is shielded, so that the optical axis L ₁ Stack tray 200 until penetration
Is descending. With this, even if the sheet is pulled out,
Be placed, it is possible to hold the upper surface of the sheet at all times to the optical axis L ₁ neighborhood.

That is, in a state where the position of the uppermost sheet P on the stack tray 200 is at an appropriate position as shown in FIG. 24A, the sheets P are bundled as shown in FIG. Suppose you were pulled out. In this case, this cannot be detected only by the first sheet surface detection sensor S205, and the upper surface of the uppermost sheet P remains down.
If the discharge of the sheet P is continued in this state, a discharge failure and a stacking failure occur due to a high drop height of the sheet. Therefore, the lowering of the paper surface is detected by the second paper surface detection sensor S207, and furthermore, the stack tray 2
00 is raised to an appropriate position. FIG.
As shown in FIG. 4C, the second paper surface detection sensor S207
To the optical axis L ₂ is cut off, it is to raise the stack tray 200. Specifically, after the stack tray 200 is lifted until the sensor S205 is shut off, the sensor S2
It falls until 05 passes (FIG. 24 (c)). By doing so, the position of the uppermost sheet P can always be properly maintained.

In the above embodiment, the optical axis L ₁
Is held in a state in which the sheet on the stack tray 200 is not shielded from light, and when the optical axis L ₂ below the optical axis L ₁ pulls out the sheet P on the stack tray 200 and enters a transparent state, the upper surface of the sheet is It had been controlled to the optical axis L ₁ near the seat in the optical axis L ₁ is held in a state of being blocked by the sheet on the stack tray 200, the optical axis L ₂ provided above the optical axis L ₁ Is detected on the stack tray 200, and the stack tray 200 is moved to the optical axis L _1.
There is lowered until the transmission, also when removing the sheet, since the optical axis L ₁ is transmitted, it is configured to raise the stack tray 200 until the light shielding, the same effect can be obtained.

In the above-described embodiment, the paper position detection sensors S205 and S207 may be provided at the following positions in addition to the above-described positions.

The light emitting unit 207a of the second paper surface detection sensor S207 is disposed near the first paper surface detection sensor S205, and the light receiving unit 207b of the second paper surface detection sensor S207 is connected to the first optical axis L. ₁ and a first plane PL ₁ parallel to the sheet P on the sheet stacking surface 200c.
Range of the lower and first proximal end side of the stack tray 200 than the optical axis L ₁ second plane PL ₂ perpendicular through (FIG. 25 (a)).

[0095], and the light receiving portion 205b of the first sheet sensor S205, and a light receiving portion 207b of the second sheet sensor S207, arranged on a substantially vertical straight line L ₃ to the sheet stacking surface 200c (FIG. 25 (B)).

[0096]

As described above, according to the present invention,
In the case where the sheet on the sheet stacking unit is pulled out, it is possible to effectively prevent a failure in discharging the sheet to the sheet stacking unit and a defective stacking.

[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 side view of a stapler and a processing tray unit.

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 side view of a swing guide and a 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, 24B, and 24C are explanatory diagrams of the operation of a second paper surface detection sensor and a stack tray.

FIG. 25 (a) shows Embodiment 2 of the present invention, (b)
FIG. 9 is a side view showing a main part of the sheet processing apparatus according to the third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sheet processing apparatus 1A Sheet processing apparatus main body 1a Outer side wall 200 Sheet stacking means (stack tray) 200a Base end of sheet stacking means (base end of stack tray) 200c Sheet stacking surface (sheet stacking surface) 201 of sheet stacking means Sheet stacking means (sample tray) 202 Elevating means (driving source, motor) 205a, 207a Light emitting section 205b, 207b light receiving section 209 Elevating means (gear) 210 Elevating means (rack) 902 Image forming section 930 Control means (control device) L ₁ First optical axis L ₂ Second optical axis L ₃ Straight line substantially perpendicular to sheet stacking surface 200c P sheet S205 First upper surface detection sensor (first paper surface detection sensor) S207 Second upper surface detection sensor (Second paper surface detection sensor) PL ₁ First plane PL ₂ Second plane

Claims (19)

[Claims] 1. A sheet stacking means which is supported so as to be able to move up and down and stacks sheets to be discharged, an elevating means which raises and lowers the sheet stacking means, and detects an uppermost position of a sheet bundle on the sheet stacking means. A first sensor for moving the sheet stacking unit by a predetermined amount via the elevating unit, and detecting that a part of the sheet bundle on the sheet stacking unit has been removed, and setting the sheet stacking unit to: A second sensor which is moved via an elevating means to return the sheet to a proper sheet discharge position. 2. The light-transmitting sensor according to claim 1, wherein the first and second sensors are light-transmitting sensors having a light-emitting unit and a light-receiving unit, and the light-emitting unit and the light-receiving unit of the first sensor are arranged on a stacking surface of a sheet bundle. 2. The sheet according to claim 1, wherein an optical axis that is substantially parallel to the second sensor is formed, and the light emitting unit and the light receiving unit of the second sensor form an optical axis that intersects the stacking surface of the sheet bundle. Processing equipment. 3. The sheet processing apparatus according to claim 2, wherein the first and second sensors detect a rear end of a sheet bundle discharged and stacked on the sheet stacking unit. 4. The sheet processing apparatus according to claim 3, wherein the light emitting units of the first and second sensors are commonly used. 5. A second sheet stacking means which can be moved up and down integrally with the sheet stacking means, and a switching means for switching a sheet so as to be guided to one of the sheet stacking means and the second sheet stacking means. The sheet processing apparatus according to any one of claims 1 to 4, further comprising: 6. A sheet processing apparatus according to claim 1, further comprising: an image forming unit configured to form an image on a sheet.
An image forming apparatus comprising: a main body discharging unit configured to discharge a sheet on which an image is formed by the image forming unit to the sheet processing apparatus. 7. The light receiving section of the second sensor, the light receiving section of the first sensor
3. The sheet processing apparatus according to claim 2, wherein the sheet processing apparatus is disposed substantially below the sensor in the vertical direction. 8. The light-receiving section of the second sensor is connected to the first light-receiving section.
A first plane passing through the optical axis of the sensor and substantially parallel to the sheet stacking surface of the sheet stacking means, and a second plane substantially vertical through the optical axis. 3. The sheet processing apparatus according to claim 2, wherein the sheet processing device is arranged in a region on a base end side of the sheet stacking unit. 9. The sheet stacking means is inclined so that the downstream side in the sheet discharging direction is higher, passes through a light receiving portion of the second sensor, further passes through an optical axis of the first sensor,
3. The image forming apparatus according to claim 2, wherein the sheet stacking means is arranged on a straight line substantially perpendicular to a sheet stacking surface of the sheet stacking means.
A sheet processing apparatus as described in the above. 10. The sheet processing apparatus according to claim 7, wherein the first and second sensors detect a rear end of a sheet bundle discharged and stacked. 11. A light emitting unit of the first and second sensors,
10. The sheet processing apparatus according to claim 7, wherein the sheet processing apparatus is commonly used. 12. A second sheet stacking means which can be moved up and down integrally with the sheet stacking means, and a switching means for switching so as to guide a sheet to either the sheet stacking means or the second sheet stacking means. The sheet processing apparatus according to any one of claims 7 to 9, further comprising: 13. A sheet processing apparatus according to claim 7, an image forming unit for forming an image on the sheet, and a main body discharging unit for discharging the sheet on which the image is formed by the image forming unit to the sheet processing apparatus. And an image forming apparatus. 14. A sheet stacking means which is supported so as to be able to move up and down and stacks sheets to be discharged, an elevating means which raises and lowers the sheet stacking means, and detects an uppermost surface of a sheet bundle on the sheet stacking means. A first sensor for moving the sheet stacking means by a predetermined amount via the elevating means, and detecting that a sheet bundle has been placed on the sheet stacking means, and changing the sheet stacking means to the elevating means. And a second sensor for returning the sheet to a proper sheet discharge position through the second sheet sensor. 15. The first and second sensors are light transmission type sensors having a light emitting unit and a light receiving unit. The light emitting unit and the light receiving unit of the first sensor are arranged on a stacking surface of a sheet bundle. The sheet according to claim 14, wherein an optical axis that is substantially parallel to the second sensor is formed, and the light emitting unit and the light receiving unit of the second sensor form an optical axis that intersects the stacking surface of the sheet bundle. Processing equipment. 16. The sheet processing apparatus according to claim 15, wherein said first and second sensors detect a rear end of a sheet bundle discharged and stacked on said sheet stacking means. 17. The light emitting section of the first and second sensors,
17. The sheet processing apparatus according to claim 16, which is commonly used. 18. A second sheet stacking means which can move up and down integrally with the sheet stacking means, and a switching means for switching the sheet stacking means so as to guide the sheet to one of the sheet stacking means and the second sheet stacking means. The sheet processing apparatus according to any one of claims 14 to 17, further comprising: 19. A sheet processing apparatus according to claim 14, an image forming unit for forming an image on a sheet, and a main body discharging unit for discharging a sheet on which an image has been formed by the image forming unit to the sheet processing apparatus. And an image forming apparatus.