JPH08169627A - Paper sheet postprocessing device - Google Patents

Abstract

PURPOSE: To not only prevent lack of uniformity of paper sheets and poor paper sheet discharging when paper sheets finished with postprocessing such as stapling are discharged and loaded on a discharge paper tray but also make it possible to load a large quantity of paper sheets on a total discharge paper tray. CONSTITUTION: This is a paper sheet postprocessing device which introduces paper sheets delivered from an image forming device therein and discharges them, after postprocessing, on a plurality of discharge paper trays T1, T2, which can be raised and lowered, through paper sheet discharging openings of a plurality of conveyance passages. A plurality of drive sources M1, M2 for respectively driving the plurality of discharge paper trays T1, T2 up and down independently and separately and a control means for separately controlling the elevating positions of the discharge paper trays T1, T2 so as to set them in a specified positions near the paper sheet discharge openings by detecting the positions of the topmost layers of the paper sheets loaded on respective discharge paper trays T1, T2 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet post-processing apparatus for binding recording sheets (sheets) on which images have been recorded by an image forming apparatus and discharging them by a stapler, and / or offset discharging. The present invention relates to a sheet post-processing device that can stack a large number of sheets.

[0002]

2. Description of the Related Art A sheet post-processing apparatus called a finisher is used as an apparatus for collating a plurality of image-recorded sheets discharged from an image forming apparatus for each number of copies and binding them by a binding unit.

The finisher has a function connected to the image forming apparatus main body and is driven in response to the sequence operation of the copying process.

Therefore, for an image forming apparatus capable of high-speed processing of the copy process, a finisher capable of high-speed processing capable of following the speed and performing its function is required.

Regarding the finisher capable of such high speed processing, Japanese Patent Laid-Open Nos. 60-142359 and 60-158463 have already been disclosed.
No. 62-239169, and JP-A Nos. 62-288002 and 63-267.
The proposals disclosed in Japanese Patent Publication No. 667, Japanese Patent Laid-Open No. 2-276691, and Japanese Patent Publication No. 5-41991 are disclosed.

In the sheet post-processing apparatus, the image-recorded sheets carried out from the image forming apparatus main body are sequentially stacked while being aligned in the intermediate stacker, and a set of sheet bundles are accommodated, and then sheets such as staples are stored. The post-processed and bound sheet bundle is sent out by the delivery means, placed on a discharge belt provided at the bottom of the intermediate stacker and conveyed, and further sandwiched by a pair of upper and lower discharge rollers to discharge the sheet. It is discharged to the tray.

[0007]

In a conventional sheet post-processing apparatus, stacker units for stacking, aligning and stapling sheets discharged from an image forming apparatus are arranged in two upper and lower stages and are aligned with each other. The discharge trays for stacking and storing the sheets that have been bound and discharged are arranged in two upper and lower stages, and the upper and lower two discharge trays are fixed to one moving body at regular intervals. Some are driven up and down by one drive source. In such a sheet post-processing apparatus, for example, when the curl amounts of the sheet bundles stacked on the upper and lower two-stage discharge trays are different,
Alternatively, when a sheet on one of the discharge trays is removed, or when the number of sheets discharged from the stacker unit is different, one of the upper and lower two sheet discharge ports is discharged. The height of the paper output tray is adjusted to the paper exit height. For this reason, there have been problems such as non-uniformity of sheets at the time of discharging the sheets, defective discharge of the sheets or the sheet discharge tray blocking the sheet discharge port, and the like.

Further, in the sheet post-processing apparatus comprising two sets of stacker units, one discharge path and one discharge tray, the length in the sheet feeding direction becomes long, and the apparatus becomes large in size. . In this sheet post-processing apparatus, the number of sheets to be stacked and stored in one sheet ejection tray is limited due to uneven sheet stacking due to curling of the sheets and swelling of staples. It is impossible to stack and store (for example, about 2000 sheets).

The object of the present invention is to solve the above-mentioned problems and improve it. As a result, it is possible to prevent unevenness of the sheets discharged and stacked on the sheet discharge tray and defective sheet discharge, and to prevent a large number of sheets from being discharged on a plurality of sheet discharge trays. To make it possible to stack sheets.

[0010]

The above object is to introduce a sheet carried out from an image forming apparatus, perform post-processing, and discharge the sheet to a plurality of sheet discharge trays that can be raised and lowered from sheet discharge ports of a plurality of conveyance paths. In the post-processing apparatus, a plurality of drive sources for individually lifting and lowering the plurality of paper discharge trays and a position of the uppermost layer of sheets stacked on the respective paper discharge trays are detected to detect the sheet discharge. This is achieved by a sheet post-processing apparatus characterized by further comprising control means for individually controlling the ascending / descending position of the discharge tray so as to be set at a predetermined position near the exit.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the sheet post-processing apparatus of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of a copying machine equipped with a sheet post-processing apparatus. 10 is a copying machine main body, 20 is a circulation type automatic document feeder (RDH apparatus), and 30 is a sheet post-processing apparatus (finisher). , Hereinafter also referred to as FNS device).

The copying machine main body 10 includes a scanning exposure unit 11, an image forming unit 12, a paper feeding unit 13, a conveying unit 14, a fixing unit 15, a paper discharge switching unit 16,
It is composed of a plurality of sheet feeding cassettes 17 and a double sided recording sheet refeeding device (ADU device) 18.

In the figure, the alternate long and short dash line indicates the conveyance path of the sheet P. An image is formed on the sheet P stored in the paper feed cassette 17 at the lower part of the copying machine body 10 by the image forming unit 12, and then the FNS device 30 passes through the conveying unit 14, the fixing unit 15, and the discharge switching unit 16.
And a circulation route to the sheet feeding unit 13 of the copying machine body 10 after the sheets P branched from the sheet discharge switching unit 16 are once stocked in the ADU device 18 and then re-fed. Consists of.

The document D stacked on the document mounting table of the RDH device 20 is fed by the copy button operation on the operation panel of the copying machine main body 10 and is fed through the paper feeding section 21 to the conveyor belt.
It is conveyed by 22 onto the platen glass 11A and set at the exposure position.

The document D is read by receiving the exposure scan of the document image by the operation of the scanning exposure unit 11, and after the reading is completed, the conveyor belt 22 is rotated again to be fed, and the document is fed through the reversing sheet discharge path 23. It is accommodated in the lowermost layer of the original stack on the original placing table.

The circulating paper feeding of the document D has been described above, but the RDH device 20 is an automatic document feeding device (ADF).
In this case, the document D, whose image has been read, advances straight and is discharged and stacked on the discharge tray 24 via the discharge rollers.

The copy image of the original D obtained by the exposure scanning is recorded on the sheet P fed from the paper feeding cassette 17 through the image processing process of the copying machine main body 10.

The sheet P on which the image is recorded is the above-mentioned ADU.
The sheet is once fed to the device 18, turned upside down, discharged from the discharge switching unit 16 with the image surface facing downward, and fed to the FNS device 30 of the present invention. The FNS device 30 is installed by adjusting the position and height so that the receiving roller 31 of the sheet P is aligned with the sheet discharge port of the copying machine main body 10, and is controlled so as to be driven according to the operation of the copying machine main body 10. Connected to the system.

The conveying path of the sheet P connected to the rear side of the receiving roller 31 is an upper offset conveying path 101 (first conveying path), a middle second conveying path 201 and a lower third conveying path 3.
It is branched into three systems of 01, and switching gates G1 and G
The sheet P is fed to any one of the transport paths by selecting the angle occupied by 2. U1 is a first stacker unit forming the second conveyance path, and U2 is a second stacker unit forming the third conveyance path.

FIG. 2 is a sectional view showing the structure of the FNS device 30.

The conveying roller pair 202 of the second conveying path 201 is
The sheet P is fed into the intermediate stacker 210 arranged with a predetermined inclination angle. A conveyance assisting belt member (guide belt) 203 is rotatably provided above the inclined lower end portion of the intermediate stacker 210, and the rear end portion of the sheet P is sent to the stapler portion. Of the three rollers that wind around the guide belt 203, the lowermost roller shaft has a conveyance assisting rotation member (impeller).
204 is provided, and when the sheet P switches back and descends on the intermediate stacker 210, the sliding contact action of the impeller 204 ensures that the sheet P contacts the stopper member 231 described later. A discharged paper pressing member 205 is oscillatably supported coaxially with the roller shaft of the impeller 204.

The intermediate stacker 210 is installed at a predetermined inclination angle, and its upper surface is flush with the upper surface of the discharge belt 211. The discharge belt 211 is wound around a driving roller and a driven roller, and is integrally provided with a discharge claw 211A that pushes out and conveys a bundle of sheets that have undergone the binding process and a projection portion 211B for home position detection.

The intermediate stacker 210 and the discharge belt 211
Below the lower end side of the stopper member 231, the paper pressing means 23
2, sheet transfer means 230 including transfer lever 233
And a stapling unit (stapler) ST1 are movably provided.

On the downstream side of the sheet stack conveyance of the intermediate stacker 210, in the vicinity of the sheet discharge section of the FNS device 30, there is provided a sheet discharge means 280 consisting of a pair of upper and lower sheet discharge rollers.

The second conveying path 201 is on the downstream side of the switching gate G2, and the conveying roller pair 202, the guide belt 203, and the impeller 20.
4, a transport unit composed of the discharged paper pressing member 205 and a stopper member
23, a sheet bundle delivery unit 230 including a sheet pressing unit 232 and a delivery lever 233, an aligning unit 240, and a stapler unit 260 including a binding unit (stapler) ST1;
The intermediate stacker 210, a discharge unit including a discharge belt 211, and a discharge unit 280 are provided. The transport unit, the sheet transfer unit 230, the aligning unit 240, and the stapler unit 26.
0, the discharge part is supported by the moving substrate of the second unit U2,
The FNS device 30 is attached and detached via a pair of left and right guide rails R1. The first stacker unit U1 is opened by opening the front door of the FNS device 30 in the drawing.
Pull out to perform maintenance such as jam clearance and supplement of staples.

The third conveying path 301 is located downstream of the switching gate G1 and has a pair of conveying rollers 302, a guide belt 303, and an impeller 30.
4, the transport unit including the discharged paper pressing unit 305 and the stopper member 33
1, sheet pressing means 332, sheet transfer means 330 composed of transfer lever 333, stapler unit 360 composed of binding means (stapler) ST2, intermediate stacker 310, ejecting section composed of aligning means 340 and second ejecting belt 311, and ejecting It is composed of paper means 380 and has the same structure as the second transport path. The second stacker unit U2, which is composed of the transport section, the sheet transfer section 330, the aligning section 340, the stapling section, and the discharging section, is connected to the FNS device 30 via the guide rail R2.
It is removable inside.

Further, on the right side of the FNS device 30, a paper discharge tray elevating means 400 is arranged. The paper output tray elevating means 400 is provided with a pair of support members 412 and 422 before and after engaging with a plurality of guide rollers 411 and 421 and moving up and down. The paper tray T1 and the second paper discharge tray T2 are respectively supported and vertically moved along a pair of fixed rails 401.

The pair of support members 412 and 422 are fixed to the elevating wires 414 and 424 stretched between the individual dedicated motors M1 and M2 and the pulleys 413 and 423, respectively.
The rotation of 2 allows the first paper discharge tray T1 and the second paper discharge tray T2 to be individually moved in parallel in the vertical direction. The details of the paper ejection tray elevating means 400 are shown in FIGS.
0, which will be described later with reference to FIG.

The control circuit built in the copying machine main body 10 and the FNS device 30 is composed of a basic circuit as shown in the block diagram of FIG. Prior to the start of the copy operation, the paper discharge mode (staple mode or non-sort mode) is selected, and the number of documents and the number of copies are set.

When the non-sort mode that does not require binding is set, the switching gates G1 and G2 are held in the initial state, the sheet P moves straight, and the receiving rollers 31 and
Intermediate roller 32, conveyor belt 102, offset roller 103,
The first sheet discharge tray T on the upper stage is discharged to the outside of the machine through the first transport path (offset transport path) 101 formed of the discharge rollers 104.
1 is placed and stored on top.

When the offset mode is selected as the paper discharge mode, the switching gates G1 and G2 are held in the initial state, the sheet P is fed upward, and the sheet P is fed upward.
The sheet is fed to 101, and is ejected onto the first sheet ejection tray T1 via the conveyor belt 102, the offset driven roller pair 103 and the ejection roller 104. The pair of offset rollers 103, which includes a driving roller and a driven roller, includes an offset driving unit that can reciprocate in a direction perpendicular to the drawing, and shifts after the trailing edge passage detection of the sheet P (sensor S4). It is configured so that the sheets P can be driven to be alternately shifted to the left and right in the sheet discharge direction according to the number of copies to be stacked and easily sorted.

When the binding mode is selected as the paper discharge mode, the switching gate G2 rotates, and the sheet P fed by the receiving roller 31 goes straight and is fed to the second conveying path 201. , Is sandwiched by the pair of transport rollers 202 in the first stacker unit U1 and once pushed up and placed on the intermediate stacker 210, the trailing edge of the sheet P is continuously rotated by the guide belt 203 and the weight of the sheet P. Slide down on the inclined surface of the intermediate stacker 210, and the stapler ST1
Binding portion (stopper member 2 of the sheet transfer means 233)
You will be guided to 31).

First sheet P corresponding to the number of originals D
After the last sheet of the sheet is detected by the sensor S1, the switching gate G1 is rotated, the sheet P of the second copy is fed downward and is fed to the third conveyance path 301, and is guided in the same manner as described above. Belt 3
Due to the action of 03, the stacker 310 is pushed up and placed. The sheet delivery means 333 of the second stacker unit U2 has the same structure as the sheet delivery means 233 of the first stacker unit U1.

On the other hand, during the feeding of the second set of sheets P,
The sheet P of the first copy, which has been laminated, is the stapler S.
Binding is performed by the operation of T1, and then the intermediate stacker 210 is pushed by the pushing back operation of the sheet passing means 233.
It is pushed up against the gravity to a predetermined position and held.

While the discharge belt 211 is driven by a motor, the rotation of the discharge belt 211 is released via a power transmission means such as a gear or a belt, and the discharge claw 211A pushes up the rear end surface of the sheet P to make one revolution and then stop. The bound bundle of sheets P of the first copy is discharged onto the first paper discharge tray T1.

During this time, the stacking of the second set of sheets P is completed, the switching gate G2 is restored again, and the second set of sheets P is operated by the operation of the stapler ST2.
The bundle of the second set of sheets P bound together is the second
The paper is discharged onto the paper discharge tray T2.

Since a plurality of sheets P on which images are recorded in this manner can be collated and bound in parallel at two positions above and below without any particular time difference, post-processing of the sheets P can be performed quickly. Will be seen.

Further, the motors M1 and M2 are operated according to the discharge amount of the sheet P, and the first paper discharge tray T1 and the second paper discharge tray T2 are lowered by the number corresponding to the number of processing plates, The sheet P can be discharged and stacked.

FIG. 4 is a sectional view of the sheet receiving portion and the sheet discharging portion, FIG. 5 is a plan view of the sheet in the direction of arrow A, and FIG. 6 is a partial perspective view of the conveying means. Although these drawings show the sheet conveying means in the second conveying path 201, the third conveying path 301 has the same structure, and therefore the second conveying path 201 will be described below as a representative.

The sheet P carried out from the guide plate of the second carrying path 201 is nipped by a carrying roller pair 202 composed of a driving roller 202A which is driven and rotated and a driven roller 202B, and is pushed up onto the surface of the intermediate stacker 210. Can be posted in this way. The drive shaft 202C of the drive roller 202A is connected to a drive source (not shown) via a coupling 202E and is driven and rotated. A plurality of drive pulleys 202D are fixed to the drive shaft 202C. The guide belt 203 that winds the drive pulley 202D winds a plurality of driven pulleys 206 provided above the bottom of the sheet stacking inclined surface of the intermediate stacker 210 and the stopper member 231 and a tension pulley 207A. It is an endless belt that does. The guide belt 203 is used to convey sheets of various sizes (B5 size or A size shown in FIG. 5).
It is placed at a predetermined position corresponding to 3 types of 7 types).
A plurality of winding rollers 207 made of a foamed elastic body are integrally formed coaxially with the tension pulley 207A.

The plurality of driven pulleys 206 are rotary shafts 206A.
It is supported and fixed to. On the axis of the rotary shaft 206A,
A conveyance assisting rotation member (impeller) 204 is fixed adjacent to the driven pulley 206 and can rotate integrally with the rotation shaft 206A. The conveyance assisting rotation member 204 is fitted to the rotation shaft 206A.
It comprises a hub portion 204A to be fixed and at least one thin plate-like elastic piece portion 204B protruding from the hub portion 204A.

By the rotation of the conveyance assisting rotary member 204,
The tip of the elastic piece draws a circular locus. The distance (clearance) at which the circular locus and the sheet mounting surface of the intermediate stacker 210 are closest to each other is set to be smaller than the maximum thickness of the sheet bundle stacked and accommodated on the intermediate stacker 210. That is, when the number of sheets P stacked on the intermediate stacker 210 is small, the sheet P conveyed from the second conveying path 201 via the conveying roller pair 202 moves backward on the intermediate stacker 210, and the inclination of the intermediate stacker 210. The corners and the weight of the sheet P easily slide down on the sheet bundle, and the rear end of the sheet P easily enters the frame of the U-shaped stopper member 231 and abuts the stopper surface. Justification is performed. When the number of sheets P stacked on the intermediate stacker 210 becomes large and the sheet bundle becomes thick (about 30 to 50 sheets), the sheet P is switched back on the sheet stack and the sheet P slides down. There is a case where the end portion jumps up and does not surely enter the frame of the stopper member 231, but comes into contact with the vicinity of the inlet and rises up to cause a jam.

The conveyance assisting belt member 203 guides and conveys the trailing end portion of the sliding sheet P in the direction of the stopper member 231 along the rotating belt surface. Further, the conveyance assisting rotation member 204 taps the trailing end of the slipping sheet P with the rotating elastic piece 204B to lightly press the bulky sheet stack on the intermediate stacker 210. It is conveyed and surely brought into contact with the stopper surface 231A of the stopper member 231.

Since it is most effective to rotate the conveyance assisting rotation member 204 near the entrance of the stopper member 231 immediately before the stapler, the thickness of the sheet bundle is about 60 mm at the position where it does not hit the opening of the stapler. The position where the number of sheets exceeds 30 is set to a position where the rotation locus of the elastic piece portion 204B approaches approximately 7 mm above the upper surface of the intermediate stacker 210.

The sheet P described in the intermediate stacker 210 has the movable aligning plate 22 and the reference surface 210A of the intermediate stacker 210.
It is regulated and aligned within the interval of 1.

Sheet P conveyed on the intermediate stacker 210
As shown in FIG. 5, when the size is B5 or A4, which is the minimum size, the three conveyance auxiliary belt members 203 and the three conveyance auxiliary rotation members 204 are brought into contact with the stopper member 231 to align the rear end sheets. Done. B4 size sheet P is 4
The rear end sheet alignment is uniformly performed on the group P and the A3 size sheets P by the group of the respective conveyance auxiliary belt members 203 and the conveyance auxiliary rotation member 204.

FIG. 7 shows a stapler unit 260 including staplers ST1 _R and ST1 _L and sheet passing means 230.
FIG. 3 is a perspective view of moving means 250. The above-mentioned unit 260 and moving means provided downstream of the upper second transport path 201 and the unit 360 and moving means provided on the lower third transport path 301 have substantially the same structure, and hence the following description of the upper stage is made. The structure and operation of the unit and the moving means provided downstream of the second transport path 201 will be described.

The sheet transfer means 230 and the staplers ST1 _R and ST1 _L are integrated into a unit 2 on the moving substrate 261.
The slide rail 251 and a slide roller (not shown) are slidable on the fixed substrate 253. On the fixed substrate 253, a rotatable timing belt TB stretched between a drive pulley TP1 connected to a drive source (stepping motor M6) and a driven pulley TP2.
It is fixed to a part of 1 by a locking member 255. The drive pulley TP1 has gears Z1, Z2, Z3, Z4, Z5, Z.
It is connected to a stepping motor M6 which is a drive source through a gear train 256 composed of six. Then, the stapler unit 260 including the sheet delivery means 230 and the staplers ST1 _R and ST1 _L is moved to a designated position by the drive and control means of the stepping motor M6.

FIG. 8A is a plan view of the aligning means 240, the stapler unit 260, and the sheet discharge portion, and FIG. 8B is A-.
Sectional view A and FIG. 8C are sectional views taken along line BB. Reference numeral 240 is an aligning means for aligning the width of the sheets P stacked on the intermediate stacker 210.

The delivery lever 233 of the sheet delivery means 230 reciprocates only when the bound sheet bundle is discharged.

The discharge belt 211 starts to rotate in the direction of the arrow through the gears Z10, Z11, the timing pulleys TP10, TP11, and the timing belt TB10 by the driving of the stepping motor M3, and the discharge claw 211A moves the sheet P after the sheet P. The first set of sheets P bound together is ejected onto the first paper ejection tray T1 while the end face is pushed up and makes one revolution and then stops.

During this time, the stacking of the second sheet P is completed, and the switching gate G2 is restored again.
The stapler ST2 operates to bind the second set of sheets P, and the second set of sheets P bound by the rotation of the discharge belt 311 is discharged onto the second discharge tray T2 as described above. To be done.

As described above, according to the FNS apparatus 30 of the present invention, a plurality of sheets P on which images are recorded can be collated and bound in parallel at two places without any particular time difference. The post-treatment of P will be performed quickly.

The stepping motor M3 operates according to the discharge amount of the sheet P, and the above-mentioned first step is performed according to the number of processed sheets.
The sheet discharge tray T1 and the second sheet discharge tray T2 are lowered so that the sheet P can be discharged.

Both the staplers ST1 and ST2 are located at one position (ST1 _R ) of the intermediate stackers 210 and 310, respectively.
By providing the sheet P in the vertically long position, the upper left one position can be bound by stapling when the sheet P is ejected in a vertically long position, but if the stapler ST1 _L is additionally installed, binding by two positions can be performed. When P is placed horizontally and ejected, the upper left part can be bound by a stapler.

FIG. 9 is a front sectional view showing the elevating means of the upper first discharge tray T1 of the elevating means 400 of the sheet post-processing apparatus 30 according to the present invention, and FIG. 10 is the lower elevating means 400 of the elevating means 400. Another front cross-sectional view showing the elevating means of the second paper ejection tray T2, and FIG. 11 is a side view showing the elevating drive of the first paper ejection tray T1 and the second paper ejection tray T2 of the elevating means 400.

In the vicinity of the bottom of the main body of the sheet post-processing device 30,
A first motor M1 for raising and lowering the first paper discharge tray T1 and a second motor M2 for raising and lowering the second paper discharge tray T2 are fixedly installed. The drive gear Z11 of the motor M1 is a two-stage gear Z12, Z13.
A rotary shaft 415, on which a pair of front and rear pulleys (drive pulleys) 413A are integrally mounted, is driven and rotated at the lower part of the device through a reduction gear train composed of a gear Z14. The pair of front and rear lifting wires 414 wound around the pulley 413A is an endless wire that winds around a pair of front and rear pulleys (driven pulleys) 413B rotatably supported on the upper part of the apparatus. The lifting wire 41
A support member 41 for holding the guide roller 411 is provided in a part of 4.
2 and the first paper ejection tray T1 are fixed. Motor M
1 drive, reduction gear trains Z11 to Z14, pulley 413
A, 413B, and the raising and lowering wire 414, and then the guide roller 411.
Moves up and down along the fixed rail 401, and the first output tray T
Raise and lower 1.

Similarly, the second motor M2 for raising and lowering the second paper discharge tray T2 has a multistage reduction gear train (Z11, Z12,
Z13, Z14) causes the support member 412 to move up and down through the pulleys 423A and 423B and the lifting wire 424. The supporting member 422 is fixed to the rail 401 by a guide roller 421.
The second paper discharge tray T2 is moved up and down along the above direction.
Reference numeral 425 is a rotary shaft that is integral with the pulley 423A.

FIG. 12 is a block diagram showing the arrangement of sensors and movement of the discharge tray of the sheet post-processing device 30 according to the present invention.

First, a sheet passage sensor S1 is provided near the sheet introduction opening of the FNS device 30, and the presence of the sheet in the FNS device 30 is detected by the passage of the sheet P. A sheet trailing edge passage detection sensor S4 is provided on the upstream side of the discharge roller 104 in the offset conveyance path 101, and the offset roller 103 is shifted in the direction perpendicular to the paper surface by the trailing edge passage detection during conveyance in the offset mode. Further downstream discharge roller 10
A sheet discharge sensor S5 is provided downstream of 4 to detect the presence of a sheet.

Paper passage sensors S6 and S42 are provided on the upstream side of the conveyance rollers 202 of the second conveyance path 201 below the offset conveyance path 101, and the passage of the sheet P is detected.
The sensor S8 detects that there is no sheet on the upper intermediate stacker 210. S16 is a sensor for detecting the paper pressing position of the upper sheet transfer means 230. S24 is discharge belt 21
1. Home position sensor. S9 is a paper discharge sensor.

Similarly, the third paper path 301 is also provided with paper passage sensors S11, S43, paper out detection sensor S12, and paper discharge sensor S13.

Next, the uppermost offset conveyance path 10 is provided in the elevating drive section of the first paper ejection tray T1 and the second paper ejection tray T2.
An offset upper stage detection sensor S69 and an offset paper removal detection sensor S70 are provided in the vicinity of the first discharge port, and the first discharge tray T is provided in the vicinity of the discharge port of the intermediate second conveyance path 201 and below the discharge port.
A tray upper limit detection sensor S27, a tray paper ejection detection sensor S29, a tray collision detection sensor S63, and a tray lower position detection sensor S28 for controlling the lifting and lowering of the No. 1 are disposed, and a tray upper end detection sensor S27 2 A tray upper limit position detection sensor S65 and a tray paper ejection detection sensor S30 for controlling the elevation of the paper ejection tray T2 are provided, and a tray lower limit position detection sensor S66 for controlling the lowering of the second paper ejection tray T2 is provided at the lowermost stage. It is arranged.

In FIG. 12, T1A is the first paper discharge tray T.
1 is the initializing position (initial setting position) during stapling, T1B is the lower limit position when stapling is performed with a maximum of 1500 sheets, and T1C is the offset lower limit position when a maximum of 2000 sheets are placed. , And T1D indicates an offset initialization position.

Further, as the ascending / descending position of the lower second discharge tray T2, T2A is the initializing position for stapling operation, and T2B is the second discharge tray when a maximum of 2000 sheets are stacked on the first discharge tray T1. 7 shows the retracted lower limit position of the paper tray T2. At the lower limit position T2B of the second paper discharge tray T2, the first intermediate stacker 210 as well as the second intermediate stacker 3 is used.
Paper output from 10 is prohibited.

FIG. 13 shows the first paper discharge tray (upper tray) T1.
6 is a flowchart showing the operation control of a second paper discharge tray (lower tray) T2. In the sheet post-processing apparatus of the present invention, the rising reference position (initialization position) of each paper discharge tray T1, T2 is the tray paper removal detection sensor S.
29, S30, and the sheet stacking amount detection on each of the discharge trays T1, T2 is performed by the tray upper limit position detection sensors S27, S65, and further, the discharge trays T1, T2 are detected.
The lower limit of is detected by the tray lower limit position detection sensors S28 and S66.
Then, the tray collision detection sensor S63 performs the middle of the upper sheet discharge tray T1. In this way, the lower tray T2
By prohibiting the above, it becomes possible to secure the stacking of 2000 sheets P in the upper discharge tray T1.

FIGS. 14 and 15 are flow charts showing the discharge tray elevating control when the sheets are stacked in the sheet post-processing device 30 and when the upper-layer sheets are taken out during the stacking. FIG. 16 shows the discharge trays T1 and T1. It is a schematic diagram explaining arrangement | positioning of T2, the upper limit sensor S69, and the paper removal sensor S70. The staple discharge tray and the offset discharge tray are the same upper first discharge tray T1. Further, since the three types of paper ejection, that is, the offset paper ejection, the stapler upper paper ejection, and the stapler lower paper ejection, perform the same lifting operation, the embodiment will be described below by the offset paper ejection.

(1) Initializing operation ... When the sheet P on the first discharge tray T1 is as shown in FIG. 16,
The first paper discharge tray T1 is lowered until the paper removal detection sensor S70 is turned off, and the state is set. First paper ejection tray T1
When is and when is lowered to, the first paper discharge tray T1 is raised, moved until the paper removal detection sensor S70 is turned on, and then brought to a fixed position and stopped (FIG. 13).
reference).

(2) Sheet stacking operation ... When the sheet P on the first sheet discharge tray T1 is in the state of and the upper limit detection sensor S69 is turned on, the first sheet discharge tray T1 is lowered, When the upper limit detection sensor S69 is turned off, the movement of the first paper ejection tray T1 is stopped to bring it into a fixed position state (Fig.
14).

(3) Paper ejection operation: When the sheet P on the first paper ejection tray T1 has run out, the first paper ejection tray T1 is raised until the paper ejection detection sensor S70 is turned on. Position it and stop it (see Figure 15).

The above-mentioned detection of the removal of the sheets stacked on the discharge tray and the above-mentioned detection for the initialization position are
Since the same sensor S29 (S30) is used, it is effective in reducing the manufacturing cost. Further, since both the initial position detecting means and the load amount detecting means conventionally require accurate accuracy, it takes a lot of time to adjust the mounting of each sensor. Was reduced to.

In this embodiment, an example in which the copying machine is connected is shown, but it is also possible to connect the copying machine to an image forming apparatus such as a printer or a facsimile.

[0074]

According to the sheet post-processing apparatus of the present invention, when the sheets discharged from the image forming apparatus are aligned and bound and then stacked and stored in a plurality of sheet discharge trays,
A large number of sheets can be stacked without causing sheet misalignment or defective delivery. Especially about 20
It has become possible to stack 00 sheets.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a copying machine including a sheet post-processing device of the present invention.

FIG. 2 is a sectional view of a sheet post-processing device.

FIG. 3 is a block diagram showing the basics of a control system.

FIG. 4 is a sectional view of a sheet receiving portion and a sheet discharging portion.

FIG. 5 is a plan view of the sheet receiving portion and the sheet discharging portion as viewed in the direction of arrow A.

FIG. 6 is a partial perspective view of a conveying unit.

FIG. 7 is a perspective view of a stapler unit and a moving unit.

FIG. 8 is a plan view, an AA sectional view, and a BB sectional view of an aligning unit, a stapler unit, and a sheet discharging unit.

FIG. 9 is a front cross-sectional view showing an elevating means for the upper first discharge tray.

FIG. 10 is a front cross-sectional view showing a raising / lowering unit of a lower second discharge tray.

FIG. 11 is a side view of the lifting means.

FIG. 12 is a configuration diagram showing a sensor arrangement and sheet discharge tray movement of the sheet post-processing apparatus.

FIG. 13 is a flowchart showing operation control of a paper discharge tray.

FIG. 14 is a flowchart showing control of raising and lowering a sheet discharge tray when stacking sheets.

FIG. 15 is a flowchart showing control of raising and lowering a paper discharge tray when paper is removed.

FIG. 16 is a schematic diagram illustrating a paper discharge tray and a sensor arrangement.

[Explanation of symbols]

 30 Sheet post-processing device (finisher, FNS device) 101 Offset transport path (first transport path) 201, (301) Second (third) transport path 210,310 Intermediate stacker (stacker) 211,311 Discharge belt 230,330 Sheet passing means 240,340 Aligning means 250 Moving means 260,360 Stapler unit 280,380 Discharging means 400 Discharging tray elevating means 401 Fixed rails 411,421 Guide rollers 412,422 Supporting members 413,413A, 413B, 423,423A , 423B Pulleys 414, 424 Lifting wires 415, 425 Rotating shafts M1, M2 Paper ejection tray lifting motors P sheets ST1, ST2 Staplers T1, T2 Paper ejection trays U1, (U2) 1st (2nd) stacker unit

Claims (4)

[Claims] 1. A sheet post-processing apparatus that introduces a sheet carried out from an image forming apparatus, post-processes the sheet, and then discharges the sheet to a plurality of sheet discharge trays that can move up and down through sheet discharge ports of a plurality of conveyance paths. A plurality of drive sources for independently raising and lowering the discharge trays and the position of the uppermost layer of the sheets stacked on the discharge trays are detected and set at a predetermined position near the sheet discharge port. The sheet post-processing apparatus is provided with control means for individually controlling the ascending / descending position of the discharge tray. 2. The plurality of sheet ejection ports, a sheet ejection port for offset ejection, a first sheet ejection port for ejecting a sheet after binding processing, and a second sheet ejection port for ejecting a sheet after binding processing. 2. The sheet post-processing apparatus according to claim 1, further comprising: 3. A plurality of discharge trays, a first discharge tray on which sheets discharged from the offset discharge sheet discharge port and the first sheet discharge port can be stacked, and the second discharge tray. 3. The sheet post-processing apparatus according to claim 1, further comprising a second sheet discharge tray on which sheets discharged from the sheet discharge port can be stacked. 4. The sheet post-processing apparatus according to claim 3, wherein the first paper ejection tray is located above the second paper ejection tray.