JP2001335224A - Sheet processing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device feeding sheets to a sheet processing device, for example, even when an image forming device becomes high speed, the device responding thereto and improving the sheet stacking performance. SOLUTION: A typical constitution of this sheet processing device is provided with a first loading means 130 temporarily loading a plurality of delivered sheets, a delivering means 180 delivering the sheets loaded on the first loading means 130, at least a second loading means 200 loading the delivered sheets, a stiffness applying rib 190 applying the stiffness in the carrier direction to the stacked sheets, and a drive means M190 moving the stiffness applying rib 190.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet processing apparatus, and more particularly, to a sheet processing apparatus for performing post-processing such as alignment and binding on sheets output from an image forming apparatus such as a copying machine or a laser beam printer. Related to an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, a plurality of conveyed sheets are temporarily stacked on a processing tray as an intermediate tray and aligned,
There has been proposed a sheet processing apparatus in which a binding process is performed on a stack tray by a bundle discharge roller pair after performing a binding process as needed. In this type of sheet processing apparatus, the stack tray is arranged at a normal stacking position having a drop below the bundle discharge roller pair in consideration of the thickness of the discharged sheet bundle and the curl formed at the rear end of the sheet. Have been.

[0003]

However, in the above-mentioned sheet processing apparatus, when the number of sheets to be discharged by the bundle discharge roller is small, the sheet is discharged in the space between the bundle discharge roller and the stack tray located thereunder. Sheet rises due to the resistance of air, the amount of ejected sheet is reduced, and the trailing edge of the sheet leans against the stacking wall and discharge rollers, causing poor ejection and poor stackability on the stack tray. There was a problem of becoming.

In order to prevent the above-described defective discharge, it is conceivable to keep the initial conveying speed of the discharged sheet low. However, this is one of the factors that hinder the high-speed image forming operation of the image forming apparatus that supplies the sheet to the sheet processing apparatus. turn into.

Accordingly, the present invention provides a sheet processing apparatus which can cope with an increase in the speed of an apparatus for feeding sheets to a sheet processing apparatus, for example, an image forming apparatus, and which has improved sheet stackability. It is intended to be.

[0006]

In order to solve the above-mentioned problems, a typical configuration of a sheet processing apparatus according to the present invention includes a first stacking unit for temporarily stacking a plurality of discharged sheets, Discharging means for discharging sheets stacked on the first stacking means, at least one second stacking means for stacking the discharged sheets, and a conveying direction for the stacked sheets arranged on the first stacking means; And a driving means for moving the stiffening rib.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a sheet processing apparatus and an image forming apparatus according to the present invention will be described with reference to the drawings.
First, the image forming apparatus will be described, and then the sheet processing apparatus will be described.

[Image Forming Apparatus] In this embodiment,
An image forming apparatus including a sheet processing device will be described. FIG. 16 is an overall sectional view schematically showing the image forming apparatus according to the present embodiment. In the apparatus configuration shown in the figure, an image forming apparatus 300 (copying apparatus) body includes an automatic document feeder (ADF) 400 for feeding a document D, a document reading unit for reading an image of the document D, and a sheet P for forming an image. Feeding section for feeding
An image forming unit 600 for forming an image on a sheet P, a sheet processing apparatus 1 for processing and stacking the sheet P on which an image has been formed, and the like are provided.

The feeding section 500 is provided with cassettes 501 and 502 for accommodating sheets P and detachably mounted on the apparatus main body, and a deck 504 arranged on a pedestal 503.
The image forming unit 600 includes a primary charging device 602, an exposure unit 603, a developing device 604, a transfer charging device 6 around a cylindrical photosensitive drum 601.
05, a separation charger 606, a cleaner 607, and the like. Further, a transport device 301 and a fixing device 608 are disposed downstream of the image forming unit 600.

When an image is formed by the image forming apparatus having the above-described configuration, first, when a feed signal is output from the control device 310 of the apparatus main body 300, the cassettes 501 and 50 of the feed unit 500 are output.
Feeding of the sheet P from the second or deck 504 is started. The skew of the sheet P fed from the feeding unit 500 is corrected by the registration roller 505, and the sheet P is fed to the image forming unit 600 in synchronization with the photosensitive drum 601. On the other hand, an image of the document D placed on the document table 401 is read by light from the light source 402 and is irradiated on the photosensitive drum 601 via the lens system 403.

The photosensitive drum 601 is uniformly charged in advance by a primary charger 602, and an electrostatic latent image is formed by the irradiated light. The electrostatic latent image is developed with toner of a developing device 604 to form a toner image. It is formed. After the toner image on the photoconductor drum 601 is transferred to the sheet P fed by the transfer charger, the sheet P is charged to the opposite polarity by the separation charger 606 and is separated from the photoconductor drum 601. . Then, the sheet P is transported by the transport device 301 to the fixing device 608.
And the image is permanently fixed by applying heat and pressure. The sheet P on which the image has been fixed is discharged to the sheet processing apparatus 1 by the discharge roller pair 302.

[Sheet Processing Apparatus] Next, the overall configuration of the sheet processing apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic sectional view illustrating a schematic configuration of the sheet processing apparatus according to the present embodiment. Sheet processing apparatus 1 shown in FIG.
In (finisher), an entrance roller pair 2 is disposed at a position facing the discharge roller pair 302 of the image forming apparatus 300, and the received sheet P is further conveyed by the first conveyance roller pair 3. A sheet detection sensor 31 for detecting the passage of the sheet P is provided near the entrance roller pair 2.
A punch unit 50 for punching a hole near the rear end of the sheet P is arranged in the transport path following the first transport roller pair 3 and is continuous with the buffer roller 5.

The buffer roller 5 is a conveying roller having a relatively large diameter, and conveys the sheet P by pressing the sheet P against the outer peripheral surface by pressing rollers 12, 13 and 14 arranged around the outside. A first switching flapper 11 is arranged on the outer periphery of the buffer roller 5, and switches between a non-sort path 21 and a sort path 22. A second switching flapper 10 is disposed downstream of the buffer roller 5, and switches between a sort path 22 and a buffer path 23 for temporarily storing sheets P. Also non-sort pass
A sheet detection sensor 33 is disposed in 21, and a sheet detection sensor 32 is disposed in the buffer path 23.

In the non-sort path 21, a second discharge roller pair 9 for discharging the sheet P onto the sample tray 201 is arranged. The sort path 22 includes a second conveying roller pair 6,
The first discharge roller pair 7 is arranged, and guides the sheet P to the processing tray unit 129 as the first stacking unit. The processing tray unit 129 has a processing tray 130 as a first stacking unit for temporarily stacking and aligning the sheets P, and a staple unit 100 having a stapler 101 for performing staple processing is arranged near the processing tray 130. I have.

[Processing Tray Unit] The processing tray unit 129 will be described with reference to FIG. 2 is a main sectional view of the processing tray unit, FIG. 3 is a bottom view of the processing tray,
FIG. 4 is a top view of the processing tray. Processing tray unit
129 is a processing tray 130 as a first loading means, a rear end stopper 131, an alignment means 140, a swing guide 150, a pull-in paddle 1
60, haunting tray 170, bundle discharge roller pair 18 as discharge means
0 and a stiffening rib 190.

The processing tray 130 is set in an inclined state by positioning the processing tray 130 on the downstream side (left side in FIG. 2) upward and on the upstream side (right side in FIG. 2) downward. As a result, the sheet that has fallen on the processing tray 130 has an action of falling by its own weight to the upstream side in the transport direction. At the downstream end of the processing tray 130, a lower discharge roller 180a that constitutes one of a bundle discharge roller pair 180 as a discharge unit is disposed.

The rear end stopper 131 is provided behind the processing tray 130 (upstream in the transport direction), and abuts and supports the rear edge of the stacked sheets P in the transport direction.
The rear end stopper 131 is formed so as to rise vertically to the stacking surface of the processing tray 130, and has an abutting support surface 131a for abutting and supporting the rear edge of the sheet P. Rear end stopper 1
Numeral 31 is configured to be rotatable and rotatable downward about a pivot pin 131b provided on the lower surface of the processing tray 130 as indicated by an arrow.
The rear end stopper 131 at the interference position with the stapler 101 is retracted to the lower surface side of the processing tray 130.

The aligning means 140 is provided on the upper surface of the processing tray and aligns the stacked sheets P in the width direction. FIG. 3 is a bottom view of the processing tray, as viewed in the direction of the arrow c in FIG. 2 (rear view). As shown in the figure, the aligning means 140 has a pair of aligning members 141 and 142, and is independently disposed on the surface of the processing tray 130 so as to oppose a lower part (rear side) and an information part (front side). ing. Alignment surfaces 141a and 142a perpendicular to the processing tray 130 are disposed on the alignment members 141 and 142, respectively, and rack gear portions 141b and 142b are assembled so as to be movable in the alignment direction. Pinion gears 143 and 144 driven by the drive motors M141 and M142 so as to be capable of normal and reverse rotation are meshed with the rack gear portions 141b and 142b, respectively. It is configured to be movable.

The swing guide 150 is rotatably supported by a support shaft 151 above the processing tray 130, and is swingably supported by a rotary cam 152 driven by a drive motor M150. An upper discharge roller 180b that constitutes the other of the bundle discharge roller pair 180 is attached to the tip of the swing guide 150, and the upper discharge roller 180b presses against the lower discharge roller 180a when the swing guide 150 comes to the closed position. The processing tray 130
The upper sheet P is stacked on a stack tray 200 as a second stacking means.
Discharge the bundle on top. The lower discharge roller 180a and the upper discharge roller 180b are driven by a drive motor M180 so as to be capable of normal and reverse rotation. The exterior of the sheet processing apparatus 1 is a bundle stacking guide.
40, and supports the rear end of the stack of sheets stacked on the stack tray 200 and the sample tray 201 in the transport direction.

The draw-in paddle 160 is fixed above the processing tray 130 at a plurality of positions on the drive shaft 161, and is rotated and stopped in a counterclockwise direction in FIG. 2 by a drive motor M160 at an appropriate timing. As a result, the sheet P discharged from the first discharge roller pair 7 to the processing tray 130 is
Processing tray 1 by the action of its own weight and retractable paddle 160
After sliding on 30, the rear edge of the sheet P is abutted against the abutting support surface 131a of the rear end stopper 131. Then, the pull-in paddle 160 stops after a predetermined time.

The haunting tray 170 extends the processing tray 130,
This is to assist the support of the stacked sheets P. FIG.
FIG. 3 is a view (plan view) seen from an arrow d in FIG.
FIG. As shown in the figure, the retractable tray 170 is located below the lower discharge roller 180a,
A rotatable cam roller 173, which is slidably mounted on a pair of guide rails 172 fixed to 71 and is rotated by a drive motor M170 about a rotary shaft 174, engages a lower surface groove 17 of the retractable tray 170.
It is moved in and out by engaging in 5. As a result, the sheet P advances and retreats in the sheet conveyance direction (along arrow X in FIGS. 2 and 4) substantially along the inclination of the processing tray 130, and the leading end thereof is positioned earlier than the center of gravity of the sheet P discharged onto the processing tray 130. It is set as follows.

The stiffening rib 190 is disposed at a substantially lower portion of the center of the processing tray 130 so as to be freely protruded and retracted by a driving motor M190 as driving means. The stiffening rib 190 is controlled by control means (not shown), and the amount of protrusion from the processing tray 130 depends on the state of the sheet P to be discharged.
Adjustable by 190.

[Operation of Sheet Processing Apparatus] Next, the operation of the sheet processing apparatus 1 during image formation will be described with reference to FIGS.
This will be described with reference to FIG. When the user designates the non-sort mode from an operation unit (not shown) of the apparatus main body, the entrance roller pair 2, the first conveyance roller pair 3, and the buffer roller 5 rotate as shown in FIG. The conveyed sheet P is conveyed. Then, the sheet P is guided to the non-sort path 21 by the first switching flapper 11, and the sheet detection sensor
When the trailing edge of the sheet P is detected by 33, the second discharge roller pair 9 is driven at a speed suitable for stacking, and the sample tray 20 is moved.
The sheet P is discharged to 1.

When the user specifies the staple sort mode, as shown in FIG. 6, the entrance roller pair 2, the first transport roller pair 3, and the buffer roller 5 rotate, and the image forming apparatus
The sheet P conveyed from 300 is conveyed. Then, the sheet P is guided to the sort path 22 by the first switching flapper 11, and is discharged to the processing tray 130 by the first discharge roller pair 7. At this time, the retracting tray 170 is at the projecting position, preventing the leading end of the sheet P from hanging down and causing a return failure, and improving the alignment on the processing tray 130. The discharged sheet P starts to move to the upstream side by its own weight, and is further securely brought into contact with the rear end stopper 131 by the rotation of the pull-in paddle 160, and is aligned in the width direction by the alignment members 141 and 142.

When all the sheets P of the first part are discharged and aligned on the processing tray 130, as shown in FIG.
Then, the upper discharge roller 180b is pressed on the sheet bundle, and the stapler 101 staples the sheet bundle.

On the other hand, the sheet P1 discharged from the image forming apparatus 300 is wound around the buffer roller 5 by the rotation of the second switching flapper 10 as shown in FIG. Stop where you have traveled. When the next sheet P2 further advances by a predetermined distance from the sheet detection sensor 31, the buffer roller 5 rotates as shown in FIG. 8, and the second sheet P2 precedes the first sheet P1 by the predetermined distance. Figure 9
As shown in (5), it is wound around the buffer roller 5 and stopped at a predetermined distance.

The bundle of sheets on the processing tray is stacked by a stack discharge roller pair 180 as shown in FIG.
The bundle is discharged onto 00. When ejecting bundles,
Moves to the home position before the sheet bundle exits the bundle discharge roller pair 180 in order to drop the sheet bundle onto the stack tray 200.

As shown in FIG. 10, when the third sheet P3 is discharged and reaches a predetermined position, the buffer roller 5 is rotated, the sheets P3 are shifted by a predetermined distance and overlapped, and the second switching flapper 10 is moved. The three sheets P are led to the sort path 22 collectively. And the swing guide as shown in FIG.
150 receives the three sheets P with the bundle discharge roller pair 180 while descending, and reverses the bundle discharge roller pair 180 when the rear end of the sheet P passes through the first discharge roller pair 7 as shown in FIG.
As shown in FIG. 18, the swing guide 150 rises and separates from the sheet surface before the rear end of the sheet comes into contact with the rear end stopper 131. The fourth and subsequent sheets P are sorted in the same way as the first copy
It is discharged onto the processing tray 130 through 22. After the third copy, the same operation as that of the second copy is performed, the set number of sheet bundles are stacked on the stack tray 200, and the process ends.

In the above-described multiple sheet conveyance,
Each sheet P is offset in the transport direction, the sheet P2 is offset downstream with respect to the sheet P1, and the sheet P3 is offset downstream with respect to the sheet P2. The offset amount of the sheet P and the rising timing of the swing guide 150 are determined based on the sheet stabilization time based on the return speed of the bundle discharge roller pair 180, that is, the processing speed of the image forming apparatus 300. In this embodiment, at a sheet conveyance speed of 750 mm / s, an offset amount (b in FIG. 13) of about 20 mm, and a bundle discharge roller pair 180 return speed of 500 mm / s, the separation position of the bundle discharge roller pair 180 is as follows. The timing is set to reach a position (a in FIG. 13) about 40 mm or less before contact with the stopper.

When the user designates the sort mode, sheets P are stacked on the processing tray 130 and a small number of sheets are discharged in a bundle in the same manner as shown in FIG. The number of sheets to be discharged as a bundle is desirably 20 or less by experiments.
The number that satisfies 20 is determined. Accordingly, the sheet processing apparatus 1 has a counting means (not shown) for counting the number of sheets. For example, if the number of sheets to be discharged is set to five, and the number of documents is four, the sheets are discharged in bundles of four sheets. If the number of originals is 5 or more, for example, 14 sheets, 5 sheets +
The sheets are aligned into 5 sheets + 4 sheets, and bundles are discharged. When the discharge of the first copy is completed, the second copy is made of the alignment members 141 and 142.
Is moved and aligned at the position offset in the width direction.
A small number of sheets are discharged in bundles in the same way as for the set. By aligning and discharging the third copy at the same position as the first copy, the sheets discharged onto the stack tray 200 are sorted by their offset positions.

[Operation of Stiffening Rib] As described above, after a plurality of sheets P are aligned on the processing tray 130,
The staple operation is started depending on the operation mode of the sheet processing apparatus, or the swing guide 150 is lowered at the time of unstitched sort discharge. In this embodiment, the drive motor M19
The timing of driving 0 and projecting the stiffening rib 190 is simultaneous with or before the swing guide 150 is lowered. The reason for projecting the stiffening rib 190 before lowering the swing guide 150 is that it is difficult to stiffen (ie, curve) the sheet bundle after the sheet bundle is nipped by the bundle discharge roller pair 180. It is.

The pull-in rib 190 is pulled in at the timing when the bundle discharge roller pair 180 is synchronized with the first discharge roller pair 7 from the discharge speed after the bundle discharge. This timing is before the bundle discharge roller pair 180 starts the reverse rotation operation. When returning the bottom sheet to the rear end stopper 131 by the reverse rotation operation of the bundle discharge roller pair 180 during the above-described three-sheet return alignment, the stiffening rib is used. If the 190 is protruded, the sheet bundle may be lifted from the lower discharge roller 180a, which may hinder the effect of the reverse rotation operation.

The stiffening rib 190 is operated when the leading edge of the sheet rises due to air resistance when the bundle is discharged, that is, when a small number of bundles are discharged. In this embodiment, the number of discharged sheets is grasped by a counting means (not shown), and the stiffening rib 190 is operated only when, for example, five or less sheets are discharged in a bundle.

The amount of protrusion of the stiffening rib 190 varies depending on the number of sheets discharged. The smaller the number of sheets detected by the counting means, the larger the amount of protrusion. Rib with ribs 19
It is configured so that 0 protrudes. The stiffening ribs are formed of metal, a sheet metal cover is attached, or a resin is plated in consideration of friction with the sheet P.

The shape of the stiffening rib 190 is formed so as to extend from the upstream to the downstream of the bundle discharge roller pair 180 as shown in FIG. 14, so that the sheet P is stiff in the sheet conveying direction. . The stiffening rib 190 is connected to the drive motor M190 by an elastic member, for example, a torsion coil spring (not shown), and is urged in a protruding direction. This makes the ribs 190 more stiff than necessary.
When a force is applied to the drive motor M190, the drive motor M190 is retracted without applying a load.

In this embodiment, the stiffening ribs are used.
Although 190 is used only for stiffening the sheet, a flag such as a photo interrupter may be provided for the stiffening rib, and it may also be used as a sheet detection sensor in the processing tray 130 except for stiffening during bundle discharge.

In this embodiment, the stiffening ribs 19 are used.
Although the movement is performed using the zero drive motor M190, the same operation can be performed by using a solenoid. The stiffening rib 190 shown in FIG. 15 is urged in the retraction direction by a stiffening rib biasing spring 192, and the link 1
91 abuts to rotate and project. The link 191 is pivotally supported by the link rotation shaft 195 and is urged by the link urging spring 193 to the position where the stiffening rib 190 is opened, but the lower end is sucked by the solenoid 196 fixed to the solenoid fixing plate 194. The upper end abuts against the stiffening rib 190 to rotate and protrude.

In this embodiment, the rotatable swing guide 150 is used to project the stiffening rib when the swing guide 150 is closed. However, the fixed lower discharge roller is fixed.
It is also possible to arrange a stiffening rib that can appear and disappear in the sheet discharge section from the sheet 180a to the stack tray 200.

In this embodiment, the stiffening ribs 19 are used.
Although it has been described that 0 protrudes before sheet discharge, it may be protruded during sheet discharge.

[0040]

As described above, in the sheet processing apparatus and the image forming apparatus according to the present invention, a small number of sheet bundles are discharged by stiffening the sheet bundle to be discharged by the stiffening ribs which can be retracted. In this case, the amount of protrusion can be secured, and even if the sheet is discharged at a high speed, the sheet can be reliably loaded on the stack tray. Accordingly, the sheet stacking performance is improved, and the image forming apparatus does not hinder a high-speed image forming operation. Therefore, it is possible to cope with high productivity of the entire apparatus.

[Brief description of the drawings]

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

FIG. 2 is a main cross-sectional view of a processing tray unit.

FIG. 3 is a bottom view of the processing tray.

FIG. 4 is a top view of the processing tray.

FIG. 5 is a diagram illustrating an operation of the sheet processing apparatus in a non-sort mode.

FIG. 6 is a diagram illustrating an operation of the sheet processing apparatus in a staple sort mode.

FIG. 7 is a diagram illustrating an operation of the sheet processing apparatus in a staple sort mode.

FIG. 8 is a diagram illustrating an operation of the sheet processing apparatus in a staple sort mode.

FIG. 9 is a diagram illustrating an operation of the sheet processing apparatus in a staple sort mode.

FIG. 10 is a diagram illustrating an operation of the sheet processing apparatus in a staple sort mode.

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

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

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

FIG. 14 is a cross-sectional view of the processing tray unit illustrating a stiffening rib.

FIG. 15 is a cross-sectional view of a processing tray unit illustrating another configuration of a stiffening rib.

FIG. 16 is an overall sectional view schematically showing the image forming apparatus according to the embodiment.

[Explanation of symbols]

 P ... sheet 1 ... sheet processing device 2 ... inlet roller pair 3 ... first transport roller pair 5 ... buffer roller 6 ... second transport roller pair 7 ... first discharge roller pair 9 ... second discharge roller pair 10 ... second switching Flapper 11… First switching flapper 12… Pressing roller 13… Pressing roller 14… Pressing roller 21… Non-sort path 22… Sort path 23… Buffer path 31… Sheet detection sensor 32… Sheet detection sensor 33… Sheet detection sensor 40… Batch stacking Guide 50: Punch unit 100: Staple unit 101: Stapler 129: Processing tray unit 130: Processing tray 131: Rear end stopper 131a: Support surface 131b: Pivot pin 140: Alignment means 141: Alignment member 141a: Alignment surface 141b: Rack gear Part 142… Alignment member 142a… Alignment surface 142b… Rack gear part 143… Pinion gear 144… Pinion gear 150… Swing guide 151… Support Shaft 152 Rotating cam 160 Pull-in paddle 161 Drive shaft 170 Retractable tray 171 Support frame 172 Guide rail 173 Rotating cam roller 174 Rotating shaft 175 Lower surface groove 180 Bundle discharge roller pair 180a Lower discharge roller 180b Upper discharge roller 190… Stiffening rib 191… Link 192… Stiffening rib biasing spring 193… Link biasing spring 194… Sheet metal plate for fixing solenoid 195… Link rotating shaft 196… Solenoid 200… Stack tray 201… Sample tray 300… Image forming apparatus 301 ... Conveying apparatus 302 ... Discharge roller pair 310 ... Control apparatus 400 ... Automatic document feeder 401 ... Document placing table 402 ... Light source 403 ... Lens system 500 ... Feeding unit 501 ... Cassette 502 ... Cassette 503 ... Pedestal 504 … Deck 505… Registration roller 600… Image forming unit 601… Photoconductor drum 602… Primary charger 603… Exposure unit 604… Developer 605… Transfer charger 606… Separation Charger 607 ... cleaner 608 ... fuser

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F053 HA06 HB01 HB12 HB13 HB16 HB22 LA02 LA07 LB03 3F054 AA01 AB01 AC02 AC05 BA02 BB02 BB12 BF09 BJ04

Claims (9)

[Claims] A first stacking unit for temporarily stacking a plurality of discharged sheets; a discharging unit for discharging sheets stacked on the first stacking unit; and at least a stacking of the discharged sheets. One second stacking unit, a stiffening rib arranged on the first stacking unit, for forming stiffness in the conveying direction on the stacked sheets, and a driving unit for moving the stiffening rib. Characteristic sheet processing device. 2. The method according to claim 1, wherein the stiffening rib is protruded by the driving means before or during the discharge of the sheet by the discharge means, and the sheet is discharged in a protruded state. Item 2. The sheet processing apparatus according to Item 1. 3. The sheet according to claim 2, wherein the driving means stores the stiffening rib after the discharging means finishes discharging the sheet stacked on the first stacking means. Processing equipment. And a counting means for counting the number of sheets stacked on the first stacking means. If the number of sheets counted by the counting means is a predetermined number or more, the driving means is not operated, 3. The stiffening rib is not projected.
Or the sheet processing apparatus according to 3. 5. The sheet processing apparatus according to claim 2, wherein an amount of protrusion of the stiffening rib by the driving unit is changed according to the number of sheets counted by the counting unit. . 6. The sheet processing apparatus according to claim 1, wherein the stiffening rib is also used as a sheet detection sensor in the first stacking unit. 7. The stiffening rib is formed by plating a metal or a resin.
The sheet processing apparatus as described in the above. 8. The stiffening rib is urged in a projecting direction by an elastic member.
The sheet processing apparatus as described in the above. 9. An image forming apparatus comprising: a sheet conveying means for conveying a sheet; an image forming means for recording an image on the sheet; and the sheet processing apparatus according to claim 1. apparatus.