JP2000327199A - Sheet post-treatment device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate inferior sheet discharging of a corner part of a sheet coming on a sheet upper limit detecting member, in a sheet discharging means having a discharge sheet sensor having a plurality of sheet upper limit detecting means for detecting the upper limits of sheets of various sizes. SOLUTION: In this sheet post-treatment device, the positions of sheet upper limit detecting members 682 to 685 arranged on parts in which a sheet passing path for a minimum-sized sheet Pa and a sheet passing path for a maximum- sized sheet Pb are not overlapped, out of a plurality of sheet upper limit detecting members 681 to 685 of a sheet upper limit detecting means 68 for detecting the topmost surface position of a stapled sheet bundle P loaded on an elevating sheet discharge tray 60, are arranged in the positions far from the paper passing path for the minimum-sized sheet Pa of rollers 24A22, 24A23, 24A31, and 24A34 close to a plurality of sheet upper limit detecting members 682 to 685.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic copying machine,
2. Description of the Related Art In an image forming apparatus such as a printer, a facsimile, or a printing machine, a sheet post-processing apparatus that receives a sheet on which an image is formed, performs post-processing such as a binding process by a binding unit, and then discharges the sheet onto an elevating sheet discharge tray. Related to the device.

[0002]

2. Description of the Related Art A sheet post-processing apparatus that performs post-processing such as binding processing by aligning a plurality of image-formed sheets discharged from an image forming apparatus main body for each number of copies has been used.

[0003] This type of paper post-processing apparatus is connected in function to an image forming apparatus main body such as a copying machine, a printer, a facsimile or the like, and is driven in response to a sequence operation of a copy or print process.

Therefore, for an image forming apparatus main body capable of performing an image forming process at a high speed, a paper post-processing apparatus capable of performing a function following the processing speed and capable of performing a high-speed processing is required. Is done.

Japanese Patent Application Laid-Open Nos. 60-142359, 60-158463 and 62-239169, and Japanese Patent Application Laid-Open Nos. 62-288002 and 63-163 already disclose paper post-processing apparatuses capable of such high-speed processing. 267667
JP-A-2-276691, JP-B-5-41991
The publications are disclosed in the above publications.

In the sheet post-processing apparatus, the image-formed sheets carried out from the image forming apparatus main body are pinched and conveyed by conveying rollers, and sequentially stacked while being aligned in an intermediate stacker, and are stacked for one book. After being stored as a sheet bundle, post-processing by a stapler or the like is performed, and the bound sheet bundle is conveyed on a discharge belt provided at the bottom of the intermediate stacker, and further nipped by a pair of upper and lower discharge rollers. The paper is discharged onto the paper discharge tray.

[0007]

(First Problem) A non-staple mode in which an image-formed sheet is discharged one by one in a sheet post-processing apparatus, and a shift processing in which a sheet to be discharged is shifted every predetermined number of sheets. Some modes enable a stapling mode in which a binding process is performed for each sheet bundle on which an image has been formed. The sheets that have been subjected to these post-processing are stacked on an elevating discharge tray driven up and down.

The stapled portion of the sheet bundle stacked on the elevating sheet discharge tray (staple process) swells and becomes thicker because the staple portion overlaps. Must be installed at

Further, a plurality of detecting members are required in order to cope with a plurality of types of paper sizes stacked on the elevating discharge tray.

Further, when the shift sorting process is performed, the number of sheet corners which is twice the number of sheet corners in the sheet size at the time of normal sheet discharge passes. If the detection member and the corner of the sheet are located at the same position, problems such as the corner of the sheet running over the detection member may occur.

(Second Problem) The sheet discharged from the image forming apparatus main body is introduced into the transport path of the transporting means of the sheet post-processing apparatus, and is sandwiched by the discharge rollers. When the following sheets are slid and stacked along the upper surface of the stacked sheets when the sheets are discharged onto the fixed sheet discharge tray, the air escapes temporarily between the sheets and accumulates. For this reason, the sheet becomes thicker, the sheet upper limit detection sensor operates when the number of sheets is equal to or less than the specified number, and a warning that sheets cannot be stacked is generated or the sheet conveyance is stopped.

(Third Problem) As shown in FIG. 19, the shape of the tip of the detection member K of the paper upper limit detection sensor of the conventional paper post-processing apparatus is such that the upper surface U has a substantially horizontal plane. Trailing end P of paper P discharged by paper discharge roller R
e remains on the upper surface U of the front end of the detection member K and stagnates, the sheet full detection sensor PS does not operate, and the fixed discharge tray T
There is a possibility that the sheet P overflows from the fixed sheet discharge tray T without detecting the full number of sheets P discharged above.

Further, since the position N at which the sheet height detecting surface of the illustrated detecting member K and the uppermost surface of the sheets P stacked on the fixed sheet ejection tray T are in a low position, the number of stacked sheets When the detection member K is pushed toward the guide plate GP with the increase in the number of sheets, the succeeding sheet P slides down on the uppermost surface of the sheet P stacked on the fixed sheet discharge tray T which is inclined and hits the guide plate GP. The detection member K may move due to the impact at that time, and the paper full detection sensor PS may malfunction.

(Fourth Problem) In the conventional sheet post-processing apparatus, when the number of sheets stacked on the fixed sheet discharge tray T increases, the sheet upper limit detection sensor P
S reacts and sends a stop signal to the image forming apparatus main body side.

FIG. 20 is a schematic view showing the process of discharging a curled sheet.

FIG. 20A shows a state in which the uppermost surface of the sheet bundle P stacked on the fixed sheet discharge tray T has reached near the detecting member K of the sheet upper limit detecting sensor PS.

FIG. 20B shows a state in which the sheet p having a large curl is discharged by the discharge roller R in the state of FIG. Shows a state of being placed on the display. The detection member K may be pressed and pushed by the curl at the rear end of the sheet p, causing the upper limit detection sensor PS to malfunction and transmit a stop signal to the image forming apparatus main body during the image forming operation.

FIG. 20C shows a state of the sheet bundle P stacked on the fixed sheet discharge tray T after the above-mentioned stop signal is transmitted. The image forming operation is stopped by the transmission of the stop signal, but after a few seconds, the curl of the abandoned paper p is naturally reduced, and the previously pressed detection member K returns. In this state,
Before removing the stacked sheet bundle from the fixed output tray T,
The stop of the image forming apparatus main body may be released.

[0019]

(1) A sheet post-processing apparatus according to the present invention which solves the above-mentioned first problem introduces a sheet discharged from an image forming apparatus main body, conveys the sheet, and stores the sheet on an intermediate stacker. In a sheet post-processing device in which a sheet stored on an intermediate stacker is bound by a binding unit, and then discharged and stacked by a discharge unit on a vertically movable discharge tray, the sheet is stacked on the vertical discharge tray. Out of the plurality of detection members of the detection means for detecting the uppermost position of the sheet bundle subjected to the binding processing, at least in a portion where the paper passage path of the minimum size paper and the paper passage path of the maximum size paper do not overlap. The position of the arranged detection member is located at a position farther than a paper passing path of the minimum size sheet of the discharge roller near the plurality of detection members (claim 1).

(2) A sheet post-processing apparatus according to the present invention which solves the above second problem is a fixed sheet discharge tray which is arranged obliquely on which sheets discharged from the main body of the image forming apparatus are stacked, and the fixed sheet discharge tray. And a guide plate for aligning the rear end of the paper stacked thereon in the transport direction.In a sheet post-processing apparatus, a surface of the guide plate facing the rear end of the sheet is formed by projecting the rear end of the sheet. And a concave portion for discharging air between the sheets when the sheets are stacked on the fixed sheet discharge tray (claim 2).

(3) A sheet post-processing apparatus according to the present invention which solves the third problem is a fixed sheet discharge tray which is inclinedly arranged for stacking sheets discharged from an image forming apparatus main body, and the fixed sheet discharge tray. A guide plate for aligning the rear ends of the sheets stacked on the sheet in the conveyance direction, and a sheet discharge sensor having a sheet upper limit detecting member for detecting the upper limit of the sheets stacked on the fixed sheet discharge tray;
In the sheet post-processing apparatus provided with, the top surface of the leading end of the detection member is formed into an inclined surface, and the end of the discharged sheet is shaped so that the end of the discharged sheet does not slide down on the inclined surface and does not stay. The paper upper limit detection surface at the leading end of the detection member is formed in such a shape that the end of the paper stacked on the paper discharge tray does not operate until reaching a predetermined upper limit. 3).

(4) A sheet post-processing apparatus according to the present invention which solves the fourth problem is a fixed sheet discharge tray which is inclinedly arranged for stacking sheets discharged from an image forming apparatus main body, and the fixed sheet discharge tray. A guide plate for aligning the rear ends of the sheets stacked on the sheet in the conveyance direction, and a sheet discharge sensor having a sheet upper limit detecting member for detecting the upper limit of the sheets stacked on the fixed sheet discharge tray;
Control means for controlling the sheet post-processing device, wherein when the end of the upper limit of the sheet abuts on the detection member for detecting the upper limit of the sheet, the discharge sensor reacts for a predetermined time or more. Only in this case, the control means determines that the upper limit of the sheets stacked on the fixed sheet discharge tray is accurate, and transmits a main body stop signal (claim 4).

According to the image forming apparatus of the present invention, the above (1) to (1)
(4) A paper post-processing device according to any one of (4) and (5).

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a sheet post-processing apparatus according to the present invention and an image forming apparatus provided with the sheet post-processing apparatus will be described with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of an image forming apparatus including an image forming apparatus main body A and a sheet post-processing apparatus FS.

The illustrated image forming apparatus main body A includes an image processing means 1, an image writing means 2, an image forming means 3, a cassette paper feeding means 4, a fixing means 5, a main body discharging means 6, A transport unit (ADU) 7 is provided. A sheet post-processing device FS is connected to the main body discharge unit 6 on the left side of the image forming apparatus main body A in the drawing.

In the image writing means 2, the output light from the semiconductor laser is applied to the photosensitive drum of the image forming means 3 to form a latent image. In the image forming means 3,
Processing such as charging, exposure, development, transfer, separation, and cleaning is performed, and an image is transferred to the sheet P conveyed from the cassette sheet feeding unit 4. The sheet P carrying the image is fixed by the fixing unit 5 and sent from the main sheet discharging unit 6 to the sheet post-processing device FS.

Alternatively, the sheet P on which single-sided image formation has been performed and which has been sent to the re-conveying means 7 by the conveying path switching plate 6A.
Are formed again on both sides by the image forming means 3 and then received from the main body discharging means 6 to the receiving portion 11 of the sheet post-processing device FS.
It is carried in.

FIG. 2 is a sectional view showing the structure of the sheet post-processing apparatus FS.

The paper transport path in the paper post-processing apparatus FS is composed of the following first transport path to third transport path.

(1) First transport path 10: A transport path in a substantially vertical direction on the right side of the drawing from the receiving section 11 to the paper discharge roller 14 through the entrance roller 12, the path a and the path b to the right of the switching gate D1, and the path b.

(2) Second transport path 20: switching gate D
(1) A conveyance path for one-sheet discharge or shift discharge sequentially to the diagonally lower path c, the conveyance roller 21, the path d above the switching gate D2, the conveyance roller 22, the path e, the conveyance roller 23, and the discharge roller 24.

(3) Third transport path 30: a path g1 that branches off from the transport roller 21 and is obliquely below the switching gate D3.
(Or path g2), a transport path for the binding process that reaches the discharge roller 24 via the transport roller 31, the path h, the transport roller 32, the intermediate stacker 33, and the discharge belt 38.

FIG. 3 is a detailed cross-sectional view of the vicinity of the sheet conveyance branch of the sheet post-processing apparatus FS.

The image-formed sheet P discharged from the image forming apparatus main body A is introduced into the receiving section 11 of the first conveying path 10, and is conveyed by the entrance roller 12 including the driving roller 12A and the driven roller 12B. Through the passage a to the right of the upper switching gate D1,
A and a driven roller 13B, the sheet is nipped and conveyed, passes through an upper passage b, is nipped by a sheet discharging roller 14 formed by a driving roller 14A and a driven roller 14B, and The paper is discharged onto the fixed paper discharge tray 15 and stacked.

In the operation section 91 of the image forming apparatus main body,
When the shift mode or the non-sort mode is set, the switching gate D1 is swung about the axis D1a by the driving of the solenoid SD1, stops at the position indicated by the broken line in the drawing, closes the passage a, and opens the passage c. State.

The image-formed paper P discharged from the image forming apparatus main body A is supplied to the receiving portion 11 of the first transport path 10,
It passes through the entrance roller 12 and enters the second conveyance path 20,
It passes through a path c formed in an open state below the switching gate D1, is nipped by a transport roller 21 composed of a driving roller 21A and a driven roller 21B, passes through a path d above a switching gate D2, Nipped by a conveying roller 22 composed of a driving roller 22A and a driven roller 22B,
The sheet is nipped by the conveying roller 23 through the path e, and is discharged and placed on the elevating sheet discharge tray 60 outside the sheet post-processing apparatus by the discharge roller 24 including the lower roller 24A and the upper roller 24B through the path f. . Reference numeral 25 denotes a swinging unit that swings the upper roller 24B.

In the operation section 91 of the image forming apparatus main body,
When the binding mode is set, the image-formed sheet P discharged from the image forming apparatus main body A is transferred to the first transport path 10.
Passes through the receiving portion 11 and the entrance roller 12, enters the second transport path, passes through the path c, is sandwiched by the transport rollers 21, and is disposed at the diagonally lower switching gate D 2 which is the third transport path 30. After passing through the lower passage g1 (or the passage g2), it is nipped by the transport roller 31 composed of the drive roller 31A and the driven roller 31B, passes through the passage h, and
2A and a driven roller 32B, the sheet P is ejected onto an inclined intermediate stacker 33, and the rear end of the sheet P abuts on a sheet abutting member (hereinafter, referred to as a stopper) 35. And stop.

Reference numeral 36 denotes a pair of aligning members movably provided on both side surfaces of the intermediate stacker 33, and lightly strikes a side edge of the sheet P in the width direction to align the width of the sheet bundle.

When a predetermined number of sheets of paper P are stacked and aligned on the intermediate stacker 33, a binding process is performed by a stapler 34 as a binding means, and a binding process is performed on the sheet bundle.

A notch is formed in a part of the sheet stacking surface of the intermediate stacker 33, and a plurality of discharge belts 38 wound around a driving pulley 37A and a driven pulley 37B are rotatably driven. A discharge claw 38a is formed integrally with a part of the discharge belt 38, and the tip of the discharge claw 38a draws an elliptical locus as shown by a dashed line in the figure. The stapled sheet bundle P is held diagonally upward by the rotating discharge belt 38 while the trailing end of the sheet bundle P is held by the discharge claw 38a of the discharge belt 38, and the lower roller unit 24A and the upper roller unit 24B. To a discharge roller 24 composed of The sheet bundle P held between the rotating discharge rollers 24 is
The sheet is discharged and stacked on the elevating sheet discharge tray 60.

FIG. 4 is a structural view showing a motor driving means of the sheet post-processing apparatus.

The drive motor M1 is driven by a timing belt TB
1, the drive roller 21 of the transport roller 21 via the TB 2
Rotate A. The gear G1 fixed on the shaft of the drive roller 21A rotates the drive roller 12A of the entrance roller 12 via the gear G2 and the timing belt TB3. The gear G1 rotates the drive roller 13A of the transport roller 13 via the gear G3 and the timing belt TB4.

The gear G4 fixed on the shaft of the intermediate pulley wound around the timing belt TB4 meshes with the gear G5 to rotate the driving roller 14A of the sheet discharging roller 14.

The drive motor M2 is driven by a timing belt TB
5, the drive roller 31A of the transport roller 31 is rotated. Gear G6 fixed on the shaft of drive roller 31A
Rotates the drive roller 22A of the transport roller 22 via the gear G7. Further, the timing belt TB5 has a gear G
8, G9, G10
Is rotated.

The drive motor M3 is driven by a timing belt TB
6, the drive roller 32A of the transport roller 32 is driven and rotated. The driven roller 32B is pressed against the drive roller 32A and is driven to rotate, thereby pinching and conveying the sheet P. The drive roller 32A rotates the transport auxiliary rotation member 32C via the timing belt TB7.

The drive motor M4 is driven by a timing belt TB
8, the upper roller unit 24B of the discharge roller 24 is rotated via the TB9, and the lower roller unit 24A is rotated via the gears G11, G12 and the timing belt TB10.
To rotate. Further, the intermediate pulley that drives the lower roller unit 24A rotates the driving pulley 37A via the timing belt TB11 and rotates the discharge belt 38.

The drive motor M5 drives and rotates the drive pulley 61 via the gear train G13, and rotates the wire 63 that winds the drive pulley 61 and the upper driven pulley 62. The base of the elevating sheet discharge tray 60 is fixed to a part of the wire 63 by a locking member 64. The lifting tray 60
The roller 65 rotatably supported by the base slides on the rail member 66 and the wire 63 rotates, so that the wire 65 can be moved up and down along the rail member 66.

FIG. 5 is a sectional view of the vicinity of the paper discharge roller 14.

The first switching gate D1 connected to the solenoid SD1 is maintained in the state shown in the figure, and opens the passage a. The paper P conveyed by the entrance roller 12 passes through the passage a, is pinched and conveyed by the conveyance roller 13, passes through the passage b formed by the guide plate 16 and the guide rib 17, and The sheet is nipped and discharged to a fixed sheet discharge tray 15 which is arranged obliquely above the apparatus.

The discharged paper P slides down on the inclined surface of the fixed paper discharge tray 15 or on the surface of the preceding paper P placed on the inclined surface. Abuts against the sheet abutting surface of the sheet and stops, and the trailing edge is aligned.

When the leading end of the sheet full detecting member 18 comes into contact with the upper surface of the sheet P near the rear end of the sheet P stacked on the inclined surface of the fixed sheet discharging tray 15, the upper limit of the predetermined number of sheet bundles is set. Detect. The rear end of the sheet full detecting member 18 turns on and off the detection optical path of the sheet full detecting sensor PS3 to generate a full sheet bundle detecting signal.

The upper surface of the leading end of the paper full detecting member 18 is formed on an inclined surface 18a formed at an inclination angle of about 45 ° from the horizontal plane. The sheet P discharged from the discharge roller 14
The rear end portion slides down the inclined surface 18a, and
Since the sheet is discharged upward, it does not stay on the upper surface of the leading end of the sheet full detecting member 18.

The lower surface 18b of the leading end of the sheet full detecting member 18 is formed at an acute angle to the horizontal plane. The lower surface side 18b of the sheet full detection member 18 abuts on the upper surface of the sheet bundle P stacked on the fixed sheet discharge tray 15 substantially parallel to the upper surface of the sheet near the rear end. Paper full detection member 18
The lower side 18b of the sheet P has such a shape, so that the sheet P stacked on the fixed sheet discharge tray 15 does not operate with the number of sheets smaller than the specified number of sheets, and the sheet full detection sensor PS
Since No. 3 does not react, the fullness of the paper P stacked on the fixed paper discharge tray 15 can be accurately detected.

One example of the height of the response of the sheet full detection sensor PS3 to the depth of the fixed sheet discharge tray 15 and the height of the operation start of the sheet full detection member 18 will be described below.

Depth of fixed discharge tray 15 until paper is full: 3
9.37 mm Number of sheets discharged per second from the image forming apparatus main body A: about 1.1 sheets Time from the reaction of the sheet full detection sensor PS3 to the transmission of the main body stop signal: 10 seconds Thickness of the paper P: about 0.1 mm paper full Operation start height of detection member 18 (L in FIG. 5): 3
5.01 mm From the above conditions, the depth of the fixed paper output tray 15 (39.37 mm)
mm), the value obtained by subtracting the thickness of 11 sheets of paper P (the number of sheets discharged for 10 seconds) was calculated, and the ideal reaction position by the sheet full detection sensor PS3 was set as follows.

L0 = 39.37 mm− (0.1 mm × 1.1 sheets × 10 seconds) = 38.27 mm FIG. 6 is a perspective view showing the guide plate 16 and the drive roller 14 A of the paper discharge roller 14. .

The contact surface of the guide plate 16 against the rear end of the sheet is
It is formed almost vertically, and is formed in a concavo-convex surface composed of a plurality of protruding surfaces (stoppers) 16a protruding from a flat portion (concave portion) 16b.

The trailing end of the sheet P discharged by the sheet discharging roller 14 and stacked on the inclined surface of the fixed sheet discharging tray 15 contacts the plurality of projecting surfaces 16a. The rear end of the sheet P is separated from the flat portion 16b to form a gap.

FIG. 7 is a schematic view of a sheet discharging section showing a process in which sheets P are stacked on the fixed sheet discharging tray 15.

FIG. 7A shows a state in which the paper P is continuously discharged to the fixed discharge tray 15 by the discharge rollers 14. Paper P
Is discharged so as to ride on the air layer on the lower surface side of the paper, and the rear end of the paper passes through the nip position of the paper discharge roller 14 and is discharged,
It falls on the upper surface of the preceding sheet bundle.

FIG. 7B shows a state in which sheets P are stacked on a sheet bundle on the fixed sheet discharge tray 15.

The paper P discharged from the paper discharge roller 14 is
Since the sheet is dropped while riding on the air layer on the lower surface side of the sheet, an air pool is formed between the sheet bundle stacked on the fixed sheet discharge tray 15 and bulges on the guide plate 16 side. I almost touch the tip of 18.

FIG. 7C shows the state of exhausting the air between the sheets when the sheets fall in the sheet discharge section, and FIG.
FIG. 3 is a schematic plan view of a sheet discharge unit.

The air trapped between the sheets is guided by the guide plate 1.
Air is exhausted from the air vent space 16c formed by the protruding surface portion 16a and the flat surface portion 16b provided on the base 6. The swelling of the paper P, which was about to touch the leading end of the paper full detection member 18, was reduced as the air between the papers was released,
The sheet is flattened, and subsequent sheets can be continuously stacked, and a specified number of sheets can be stored.

FIG. 8 is a flowchart showing the control of a paper discharge sensor for detecting the fullness of a bundle of paper stacked on the fixed paper discharge tray 15, and FIG. 9 is a block diagram showing the control of the paper post-processing device FS.

As shown in FIG. 20, in the conventional sheet post-processing apparatus FS, when the number of stacked sheets on the fixed sheet discharge tray T increases, the sheet sensor PS3 for temporarily detecting the sheet full due to the curl of the sheet. Has reacted, and the image forming apparatus main body A
Sends a processing stop signal to the user.

In the state shown in FIG. 20 (b), when the paper-full detection sensor PS3 is turned on, the control means 90 of the paper post-processing apparatus of the present invention immediately processes the image forming apparatus main body A. The timer 92 is started without sending a stop signal, and after a predetermined time has elapsed, the paper discharge sensor P for detecting a paper full state.
When the ON state of S3 is maintained, a processing stop signal is transmitted to the image forming apparatus main body A.

The sheet fullness detection sensor PS for the timing condition for transmitting the processing stop signal to the image forming apparatus main body A
The minimum reaction time of No. 3 was set in the timer 92 by actually measuring the time when the curl of the paper P disappeared due to spontaneous return. For example, the transmission waiting time is set to 10 seconds. As a result, it is possible to detect an accurate upper limit of the sheets stacked on the fixed sheet discharge tray 15.

FIG. 10 is a cross-sectional view of the sheet discharging means showing a state in which the sheet P is discharged by the discharge roller 24 after the binding process.
FIG. 11 is a plan view of the sheet discharging means.

On the intermediate stacker 33, an alignment member 36,
The discharge belt 38 and the staplers 50A and 50B are movably arranged.

The two alignment members 36 are arranged symmetrically with respect to the center line CL, and can be simultaneously moved in a direction orthogonal to the direction in which the paper P is transported. The discharge claw 38a fixed to a part of the two discharge belts 38 is used to hold the bound sheet bundle P
The sheet bundle P is sent to the discharge roller 24 by contacting the rear end of the sheet bundle P. The two sets of staplers 50A and 50B are arranged symmetrically with respect to the center line CL, are movable in the sheet width direction according to the sheet size, and have staples SP _A and SP _B.
Is supported so as to be swingable so that the driving angle can be selected.

The discharge roller 24 is a lower roller unit 24A.
And an upper roller unit 24B. The upper roller unit 24B is oscillated by the oscillating means 25, and comes into and out of contact with the lower roller unit 24A at a fixed position so as to be able to open and close.

When large-size paper such as A3 size or B4 size is discharged from the transport roller 32 onto the intermediate stacker 33, the discharge roller 24 is kept open so that the leading end of the large-size paper can be stacked. To After the binding processing, the discharge roller 24 is brought into a press-contact state, and pinches and discharges the bound sheet bundle P.

FIG. 12A is a sectional view showing the upper limit position of the elevating sheet discharge tray 60 when the binding process is not performed (non-staple mode).

Above the rear end reference member 67, a sheet upper limit detecting means 6 comprising a photo interrupter type discharge tray upper limit detecting sensor PS4 and a swingable sheet upper limit detecting member 681.
8 are installed. When the ascending / descending sheet tray 60 is driven up and the tip 681A of the paper upper limit detecting member 681 contacts the upper surface of the ascending / descending sheet tray 60 or the upper surface of the sheet P placed on the ascending / descending sheet 60, The rear end portion 681B of the sheet upper limit detection member 681 opens the light detection unit of the sheet discharge tray upper limit detection sensor PS4 to be in the switch-off state, and stops the drive of the elevation sheet discharge tray 60. The stop position of the elevating sheet discharge tray 60 is a position where the upper surface of the elevating sheet discharge tray 60 or the upper surface of the paper P placed on the elevating sheet discharge tray 60 is pressed against the winding roller 24A3 with a predetermined pressure.

In this state, the rotating take-up roller 24A3 is constantly pressed against the paper P at a predetermined pressure and
To the rear end reference member 67 to align the rear end. As the number of sheets P stacked on the elevating sheet tray 60 increases, the elevating sheet tray 60 is driven downward, and the uppermost surface of the sheets P stacked on the elevating sheet tray 60 is at the upper limit of the sheet tray. The detection is controlled by the detection sensor PS4 and the paper upper limit detection member 681, and is always kept at a constant upper surface height and pressed against the outer peripheral surface of the winding roller 24A3 with a predetermined pressure.

FIG. 12B is a cross-sectional view showing the upper limit position of the elevating sheet discharge tray 60 when performing the binding process (staple mode).

When the ascending / descending sheet tray 60 is driven upward, the leading end 681A of the sheet upper limit detecting member 681 is moved upward.
When it comes into contact with the upper surface of the bound sheet bundle P placed thereon, the rear end portion 681B of the sheet upper limit detecting member 681 opens the light detecting section of the sheet discharge tray upper limit detecting sensor PS4 to be in the switch off state. Then, the driving of the elevating sheet discharge tray 60 is temporarily stopped. Subsequently, the control unit and the driving unit are connected to the lifting tray 6
0 is lowered and stopped at a predetermined position.

The stop position of the elevating sheet discharge tray 60 is such that the sheet bundle P placed on the elevating sheet discharge tray 60 is
This is a position having a gap m not in contact with A3. In this state, the sheet bundle P discharged from the discharge roller 24 is placed on the elevating sheet discharge tray 60, and the rear end of the sheet bundle P enters below the winding roller 24A3 and contacts the rear end reference member 67. And stop.

Since a gap m is maintained between the outer peripheral surface of the winding roller 24A3 and the upper surface of the elevating sheet discharge tray 60 or the upper surface of the sheet bundle P, the staples SP hit on the sheet bundle P.
However, it does not come into contact with and damage the outer peripheral surface of the winding roller 24A3.

As the number of sheet bundles P stacked on the elevating sheet tray 60 increases, the elevating sheet tray 60 is driven downward, and the uppermost surface of the sheet bundle P stacked on the elevating sheet tray 60 becomes The detection is controlled by the discharge sensor PS4 for detecting the discharge tray upper limit and the paper upper limit detection member 681, and is always maintained at a constant gap m.

FIG. 13A is a side view showing a main portion near the central portion of the paper discharging means, FIG. 13B is a front view showing the vicinity of the central portion of the paper discharging device, and FIG. FIG. 14 is a front view showing the vicinity of both ends of the means, and FIG. 14 is a perspective view of the paper upper limit detecting means.

The lower roller unit 24A of the discharge roller 24
Are three lower rollers 24A2 on the axis of the rotation shaft 24A1.
1, 24A22, 24A23 and five winding rollers 2
4A31, 24A32, 24A33, 24A34, 24
A35 is provided. The upper roller unit 24B includes three upper rollers 24B21, 24 on the axis of the rotation shaft 24B1.
B22 and 24B23.

The lower roller 24A21 and the upper roller 24B21
Are disposed opposite to each other, and the lower roller 24A22 and the upper roller 24
B22 and the lower roller 24A23 are opposed to the upper roller 24B23.

These three sets of lower roller and upper roller are
The sheet bundle P of any size from the minimum size to the maximum size is nipped and transported.

A swing shaft 680 integral with the plurality of sheet upper limit detecting members 681 to 685 is swingably supported by a pair of left and right support plates 68A fixed to the housing of the sheet post-processing apparatus FS. A plurality of paper upper limit detecting members 681 to
Reference numeral 685 denotes an oscillating shaft 68 in a direction orthogonal to the sheet conveying direction.
0, a plurality of them are arranged and fixed (five in the figure). Each leading end 681 of the plurality of paper upper limit detecting members 681 to 685
A, 682A, 683A, 684A, 685A have the same shape and are arranged in the same phase.
Or the upper surface of the paper P stacked on the elevating sheet discharge tray 60.

Of the plurality of upper limit detecting members 681 to 685, only the upper limit detecting member 681 fixed substantially at the center of the swing shaft 680 has a rear end portion 681B and detects the upper limit of the discharge tray. Paper ejection sensor PS4.

Out of the plurality of upper limit detecting members 681 to 685, the other upper limit detecting members 682 to 685 except for the upper limit detecting member 681 near the central portion are arranged in the sheet width direction with staples. It is set near the position where the SP is driven.

FIG. 15 shows a staple needle SP that has been hit at one location at the corner of the rear end Pe of a sheet bundle P of various sizes.
It is a top view showing the position of.

The stapler 50A, 50B shown in FIG.
Is tilted at an angle of 45 ° by the rocking means,
The sheet bundle P travels straight in a direction parallel to the rear end portion Pe, and the predetermined distances L1, L corresponding to the corners of the sheet bundle of a predetermined size.
2. Stop at any of the staple positions L2, L3,
The staples SP _A and SP _B are hit at one place.

The positions where the staples SP _A and SP _B are driven are distributed at one position near one of the corners in the width direction of the sheet bundle P or at equal intervals from the center of the sheet bundle P in the width direction. Part. Furthermore, these staples S
The position where P is driven is set at a position in the sheet width direction that differs depending on the sheet size.

FIG. 16 is a side view of the sheet discharging means.

When a large number of paper bundles P bound by the stapler 50 are stacked on the elevating paper discharge tray 60, the staples SP, which are stapled at the paper bundle corners, overlap and become high, and the paper bundles become high. Only the binding processing portion of P becomes thicker. The leading end of the sheet upper limit detecting member 682 disposed near the corner of the sheet bundle comes into contact with the upper surface of the corner of the sheet bundle P having the increased thickness and is pushed up, and the swing shaft 680 is rotated.
Rocked around.

The swing of the swing shaft 680 causes the paper upper limit detecting member 6 near the center integrated with the paper upper limit detecting member 682 to be integrated.
81 is also swung at the same time, and its rear end 681B blocks the detection optical path of the discharge tray upper limit detection sensor PS4. In response to the detection signal of the sheet discharge tray upper limit detection sensor PS4, the control means 9
0 drives the drive motor M5, and lowers the elevating sheet discharge tray 60.

After the elevating sheet tray 60 is lowered and a predetermined time has elapsed, the lowering of the elevating sheet tray 60 is stopped by the control means 90. In this stopped state, a predetermined interval m is formed between the uppermost surface of the sheet bundle P stacked on the elevating sheet discharge tray 60 and the outer peripheral surface of the winding roller 24A3.

A plurality of paper upper limit detecting members 681 to 685
Are formed in the same shape and the same phase, it is necessary to detect the highest position of the staples SP _A and SP _B stapled at each corner of the paper of various sizes shown in FIG. Can be.

FIG. 17 is a side view showing the relative positions of the paper upper limit detecting means 68, the lower roller unit 24A and the paper size.

The plurality of upper limit detecting members 682 to 685 of the detecting means for detecting the position of the uppermost surface of the bound sheet bundle P stacked on the elevating sheet discharge tray 60 are configured to at least pass through the sheet Pa of the minimum size. The position of the paper upper limit detecting members 682 to 655 arranged at a portion where the paper path does not overlap the paper passing path of the maximum size paper Pb is the paper upper limit detecting member 6.
The discharge rollers 24 in the vicinity of 82 to 685 are arranged at positions farther than the paper passing path of the minimum size paper Pa.

For example, when the minimum size paper Pa is B6R, the paper width W1 is 128 mm, and when the maximum size paper Pb is A3, the paper width W2 is 297 mm. Therefore, in the center-based transport method in which the sheets p of each size are arranged symmetrically with respect to the center line CL, a portion where the sheet passing path of the smallest sheet Pa and the sheet passing path of the largest sheet Pb do not overlap. Are set to α1 = α2 = (W2−W2) on both sides of the sheet passing width W1.
1) / 2 are formed. For example, the minimum size paper P
a is B6R and A3 is the maximum size paper Pb, the intervals α1 and α2 of the non-overlapping portions are both 84.
5 mm.

The position of the paper upper limit detecting members 682, 683, 684, and 685 disposed in the non-overlapping portions is determined by the position of the paper Pa of the minimum size of the discharge roller 24 near the paper upper limit detecting members 682 to 685. Arranged to be farther from the route.

That is, the paper upper limit detecting member 683 is disposed closer to the axial end than the position where the lower roller 24A22 is disposed, and within the area of the interval α1 between the non-overlapping portions. Also,
Closer to the axial end direction of the winding roller 24A31 arranged further in the axial end direction than the arrangement position of the lower roller 24A22,
A paper upper limit detecting member 682 is arranged in the area of the interval α1 between the non-overlapping portions.

Similarly, a paper upper limit detecting member 684 is arranged in a region close to the outside of the lower roller 24A23 and at an interval α2 of a non-overlapping portion. Further, a paper upper limit detecting member 685 is disposed in the area close to the axial end direction of the winding roller 24A34 and at the interval α2 between the non-overlapping portions.

When the paper P of various sizes is discharged from the second transport path 20 to the elevating discharge tray 60 in the non-sort mode, the lower roller unit for transporting the paper P of various sizes similarly to the staple mode. 24A, paper upper limit detecting members 681 to 685 are arranged.

FIG. 18 shows the state of the transport roller 2 in the second transport path 20.
3 is a side view showing the relative positions of the various sizes of paper P, the lower roller unit 24A, and the paper upper limit detecting means 68 when the various sizes of paper P shifted in 3 are discharged to the elevating discharge tray 60. FIG.

The sheet P shifted by the transport rollers 23 and shifted by the moving distance β in the sheet width direction from the center line CL of the sheet discharging means is discharged to the elevating sheet discharging tray 60 by the discharging rollers 24.

Among the plurality of upper limit detecting members 681 to 685 of the detecting means for detecting the uppermost position of the sheet P stacked on the elevating sheet discharge tray 60 after the shift processing, the sheet width W1 of the smallest size and the largest size are detected. 17, a lower roller 24A22 and a paper upper limit detecting member 683, and a winding roller 24A31 and a paper upper limit detecting member 682 are arranged in a region of an interval α1 of a portion that does not overlap with the paper width W2.

In the area of the interval α2, the take-up roller 24A34 and the paper upper limit detecting member 685 are arranged.

In order to detect the upper limit of the bound sheet bundle P discharged onto the elevating discharge tray 60, a plurality of paper upper limit detection members 681 to 685 of the discharge tray upper limit detection sensor PS4 and the paper upper limit detecting means 68. Is provided.

There are many types of width size of the sheet nipped and conveyed by the discharge roller 24. For example, the paper width is shown in FIG.
7, In addition to the six types from B6R to A3 shown in FIG.
F4 size, 8.5-inch width size, 11-inch width size, etc. are used, and the corners of these various types of paper strike or climb over any of the plurality of paper upper limit detection members 681 to 685. And a detection failure occurs.

Further, when the shift processing is performed, the number of the corner portions which is twice the number of the paper corner portions in the sheet size at the time of the normal discharge is set to a plurality of the sheet upper limit detecting members 681 to 68.
Pass 5

If the paper upper limit detecting members 681 to 685 and the corner of the paper are located at the same position, the paper upper limit detecting member 6
The corner portion of the paper rides on any one of the sheets 81 to 685, causing a problem such as a detection failure.

Except for the paper upper limit detecting member 681 at the center,
By disposing the paper upper limit detection members 683 and 684 on both sides near the outside of the lower rollers 24A22 and 24A23, the lower rollers 24A22 and 24A23 prevent the paper from climbing onto the paper upper limit detection members 683 and 684.

Further, by disposing the paper upper limit detecting members 682 and 685 near the outer side of the winding rollers 24A31 and 24A34 outside the lower rollers 24A22 and 24A23, the winding rollers 24A31 and 24A34 become
The paper is prevented from running over the paper upper limit detecting members 682 and 685.

By arranging the paper upper limit detecting members 682 to 685 in the vicinity of each roller body of the discharge roller 24, the bound sheet bundle P, the sheet P discharged in the non-sort mode, and the sheet P discharged in the shift processing mode. In any of the paper discharge modes of the paper P to be printed, the paper is successfully discharged.

In the embodiment of the present invention, the paper post-processing apparatus connected to the main body of the copying machine represented by the main body of the image forming apparatus has been described. The present invention is also applicable to a paper post-processing device to be used by connection.

[0117]

According to the paper post-processing apparatus of the present invention, the following effects can be obtained.

(1) In a sheet discharging means provided with a sheet discharging sensor having a plurality of sheet upper limit detecting members for detecting the upper limit of sheets of various sizes, it is possible to eliminate a sheet discharging defect in which a corner portion of a sheet runs on the sheet upper limit detecting member. You can do it.

(2) It is possible to prevent erroneous detection of the paper full detection sensor, and to reliably store the paper sheets continuously discharged to the fixed paper discharge tray within the specified number of sheets.

(3) It is possible to easily and accurately detect the paper full state on the fixed paper discharge tray without reacting the paper discharge sensor with a smaller number of stacked paper sheets and without providing a complicated mechanism. .

(4) It is possible to prevent the occurrence of an erroneous detection signal due to the temporary response of the paper ejection sensor due to the curl of the paper, and to detect the normal upper limit of the paper stacking.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an image forming apparatus including an image forming apparatus main body and a sheet post-processing apparatus.

FIG. 2 is a cross-sectional view illustrating a configuration of a sheet post-processing apparatus.

FIG. 3 is a cross-sectional view of a sheet transport unit of the sheet post-processing device.

FIG. 4 is a configuration diagram illustrating a motor driving unit of the sheet post-processing apparatus.

FIG. 5 is a cross-sectional view near a paper discharge roller.

FIG. 6 is a perspective view showing a guide plate and a driving roller of a paper discharge roller.

FIG. 7 is a schematic view of a paper discharge unit illustrating a process in which paper is stacked on a fixed paper discharge tray.

FIG. 8 is a flowchart illustrating control of a sheet ejection sensor that detects a fullness of a sheet bundle stacked on a fixed sheet ejection tray.

FIG. 9 is a block diagram illustrating control of the sheet post-processing apparatus.

FIG. 10 is a cross-sectional view of a sheet discharging unit showing a state in which the sheet is discharged by a sheet discharging roller after a binding process.

FIG. 11 is a plan view of the paper discharging means.

FIG. 12 is a cross-sectional view illustrating an upper limit position of the elevating sheet tray when the binding process is not performed, and a cross-sectional view illustrating the upper limit position of the elevating sheet tray when performing the binding process.

FIG. 13 is a side view showing a main part in the vicinity of a central portion of the sheet discharging means.
FIG. 3 is a front view showing the vicinity of a central portion of the sheet discharging means, and a front view showing the vicinity of both ends of the sheet discharging means.

FIG. 14 is a perspective view of a paper upper limit detecting unit.

FIG. 15 shows a state in which the sheet bundle of various sizes has
FIG. 4 is a plan view showing the position of a staple stuck at one place.

FIG. 16 is a side view of the sheet discharging means.

FIG. 17 is a side view showing the relative positions of the paper upper limit detection unit, the lower roller unit, and the paper size.

FIG. 18 is a side view illustrating the relative positions of the shifted sheets of various sizes, the lower roller unit, and the sheet upper limit detecting unit.

FIG. 19 is a schematic view of a sheet discharging means of a conventional sheet post-processing apparatus.

FIG. 20 is a schematic view of a conventional paper discharging means showing a paper discharging process of curled paper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st conveyance path 14 Discharge roller 15 Fixed discharge tray 16 Guide plate 16a Projection surface part 16b Flat part (concave part) 18 Paper full detection member 20 2nd conveyance path 21, 22 Transport roller 23 Transport roller 24 Discharge roller 24A Lower Roller unit 24B Upper roller unit 24A21 to 24A23 Lower roller 24A3, 24A31 to 24A35 Roll-up roller 30 Third transport path 31, 32 Transport roller 33 Intermediate stacker 38 Discharge belt 50, 50A, 50B Stapler 60 Elevating discharge tray 68 Paper upper limit detecting means 680 swing shaft 681 to 685 paper upper limit detecting member 90 control means 91 operating section 92 timer A image forming apparatus main body D1, D2, D3 switching gate FS paper post-processing apparatus M1, M2, M3, M4, M5 drive motor P paper, Paper bundle Pa Paper Pb maximum size sheet PS3 paper full detecting paper discharge sensor PS4 ejection tray upper limit detection for the sheet discharge sensor SD1 of's, SD2, SD3 solenoid a, b, c, d, e, f, g1, g2, h passageway

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshitaka Matsumoto 3-51-4 Kanamecho, Toshima-ku, Tokyo (72) Inventor Hirohiko Okabe 47, 1067 Wakamatsucho, Tokorozawa-shi, Saitama (72) Inventor Takahashi Tadahiro F-term (reference) 3-3 Hibarigaoka, Hoya-shi, Tokyo 2H072 AA09 AA28 CA01 GA08 3F054 AA01 AB01 AC02 AC03 AC04 AC05 BA04 BD02 BG11 BH13 BH14 CA12 CA23 CA31 DA01 DA11 3F106 JA03 JA07

Claims (5)

[Claims] 1. A sheet discharged from an image forming apparatus main body is introduced, conveyed and stored on an intermediate stacker, and after the sheet stored on the intermediate stacker is bound by a binding unit,
In a sheet post-processing apparatus which discharges and stacks on a vertically movable paper tray by a paper discharging means, a plurality of detecting means for detecting an uppermost surface position of a bound sheet bundle loaded on the vertically movable paper discharging tray Among the detection members, at least the position of the detection member arranged at a portion where the paper passage path of the minimum size paper and the paper passage path of the maximum size paper do not overlap is the paper ejection near the plurality of detection members. A sheet post-processing apparatus, wherein the sheet post-processing apparatus is disposed at a position farther than a sheet passing path of a sheet of a minimum size of a roller. And a guide plate for aligning a rear end of a sheet stacked on the fixed sheet discharge tray in a conveying direction, wherein the sheet discharge sheet is stacked on the fixed sheet discharge tray. In the sheet post-processing apparatus provided with, a sheet stopper is disposed on the fixed sheet discharge tray, and a convex stopper portion that abuts a surface of the guide plate facing the sheet rear end against the sheet rear end. And a concave portion for discharging air between the sheets. And a guide plate for aligning a rear end of a sheet stacked on the fixed sheet discharge tray in a conveying direction, the fixed sheet discharge tray being configured to stack sheets discharged from the image forming apparatus main body. A sheet discharge sensor having a sheet upper limit detection detecting member for detecting an upper limit of sheets stacked on the fixed sheet discharge tray, wherein the upper surface of the leading end of the detecting member is formed on an inclined surface. The end of the sheet to be ejected is shaped so that the end of the sheet slides down the inclined surface so as not to be stagnated, and the sheet upper limit detection surface at the leading end of the detection member is stacked on the sheet ejection tray. A sheet post-processing device, wherein a shape of the sheet post-processing device is such that an end of the sheet does not operate until a predetermined upper limit is reached. And a guide plate for aligning a rear end of a sheet stacked on the fixed sheet discharge tray in a conveying direction, wherein the fixed sheet discharge tray is configured to stack sheets discharged from the image forming apparatus main body. A sheet discharge sensor having a sheet upper limit detection member for detecting an upper limit of sheets stacked on the fixed sheet discharge tray, and control means for controlling a sheet post-processing device; Only when the end of the upper limit of the sheet abuts on the detecting member for detecting the upper limit of the sheet and the discharge sensor is caused to react for a predetermined time or more, the control unit determines that the upper limit of the paper stacked on the fixed discharge tray is accurate. A sheet post-processing device for transmitting a main body stop signal. 5. An image forming apparatus comprising the sheet post-processing device according to claim 1. Description: