JP3403053B2 - Discharge sheet stacking apparatus and image forming apparatus equipped with this apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge sheet stacking device for discharging sheets after temporarily stopping them for double-sided image processing, stapling processing, and the like, and a printer and a copying machine provided with this device. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, a network environment such as a personal computer has been developed. The image forming apparatus placed under such a network environment is shared by a plurality of users and used in various ways. Among these requests are, for example, double-sided image processing and stapling processing.

In order to meet such demands, a printer, which is an image forming apparatus, is provided with a discharged sheet stacking device. This apparatus is capable of performing a stapling process by temporarily stopping and waiting the sheet in the sheet conveyance path.

The sheet conveyed in the vertical conveying section is received by the discharge sheet stacking device by the pair of aligning carry-in rollers and guided to the upper surface of the aligning table which is the sheet stacking section. Then, the sheet is brought into contact with the leading end stopper portion of the sheet stopper and stacked on the alignment table.

When a predetermined number of sheets are stacked on the aligning table to form a bundle, the sheets are aligned in the feeding direction and the direction perpendicular thereto, and are sandwiched by a bundle conveying roller pair which is a sheet conveying roller pair. Then, the sheets are conveyed and discharged from the discharged sheet stacking device in a bundle state when the conveying path is released by rotating the front end stopper portion and retracting.

[0006]

By the way, in order to simplify the structure and to reduce the cost, the above-mentioned discharge sheet stacking device has a clutch or the like in the lower bundle conveying roller arranged in the lower side of the pair of bundle conveying rollers. The drive connecting / disconnecting means is not provided.

Therefore, the lower bundle conveying roller supports the sheet contacting the leading end stopper portion from below and continues to rotate. Further, since the lower conveyance roller conveys a bundle of sheets,
It is arranged at a height substantially flush with the upper surface of the matching table.

As described above, since the lower bundle conveying roller continues to rotate at a position substantially flush with the upper surface of the aligning table, the lower bundle conveying roller continues to rub against the lower surface of the lowermost sheet contacting the leading end stopper portion. .

Therefore, the carry-out sheet stacking device has a problem that the surface of the sheet is damaged or the image formed on the sheet is disturbed to damage the image.

[Object] The present invention solves the above problems by
An object of the present invention is to provide an ejected sheet stacking device that does not scratch the surface of a sheet or damage an image formed on the sheet, and an image forming apparatus including this device.

[0011]

The above-mentioned problems can be solved by the following discharged sheet stacking device.

A sheet stacking section capable of stacking a plurality of sheets, a storage means for storing the sheet on the sheet stacking section, and a pair of sheet conveying rollers for sandwiching and discharging the sheet on the sheet stacking section are provided. In a discharge sheet stacking device in which one roller of the sheet conveying roller pair is located on the side of the sheet stacking portion and the other roller can come into contact with and separate from the one roller from above, A sheet receiver that is positioned to support the sheet on the sheet stacking unit, releases the sheet by the storage unit, and retracts when the other roller descends to bring the sheet into contact with the one roller. A member is provided.

The storage means is a sheet stopper for receiving and receiving the sheet by retracting the sheet stacking portion, the sheet receiving member is a rotatable link piece interlocked with the sheet stopper, and the link piece is the sheet stopper. When it projects upward from the sheet stacking section, it projects above the one roller, and it retracts when the sheet stopper is retracted into the sheet stacking section.

The sheet receiving member is a link piece which is urged to rotate upward by the elastic body in a direction projecting upward from the one roller, and the link piece is pressed by the other roller that descends and retracts.

The sheet receiving member is a rotary cover that is rotatably arranged coaxially with the one roller and is urged to rotate above the one roller by an elastic body.
The rotating cover is rotated and retracted by the contact of the other roller that descends.

The above problem can also be solved by an image forming apparatus provided with an image forming section for forming an image and the discharged sheet stacking device described in any one of the above.

[Operation] The sheet sent from the outside is
In order to receive the stapling process and the like, the sheet is stored on the sheet stacking unit by the storage unit and supported by the sheet receiving member.
Thereafter, when the storage is released and the other roller is lowered, the sheet is transferred from the retracted sheet receiving member to the one roller, is sandwiched by the pair of sheet conveying rollers, and is discharged.

Therefore, the sheet is supported by the sheet receiving member while being stored in the sheet stacking unit, and does not come into contact with one of the rollers that are constantly rotating and rub against it.

When the storage means is a sheet stopper that projects in and out of the sheet stacking portion and receives the sheet, and the sheet receiving member is a rotatable link piece that is interlocked with the sheet stopper, the link piece has a sheet stopper that is located above the sheet stacking portion. When the sheet stopper projects into the sheet stacking portion, the sheet stopper is projected upward from one roller to support the sheet, and when the sheet stopper is retracted into the sheet stacking portion, the sheet is retracted and reliably delivered to the one roller. Therefore, the sheet is supported by the link piece while being stored in the sheet stacking unit, and does not come into contact with one roller that is constantly rotating and rub against it.

If the sheet receiving member is a link piece that is urged to rotate upward by one of the rollers by the elastic body, the link piece is pressed by the other roller that descends to reliably retract the sheet. Hand over to one roller. Therefore, the sheet is supported by the link piece while being stored in the sheet stacking unit, and does not come into contact with one roller that is constantly rotating and rub against it.

If the sheet receiving member is a rotary cover that is rotatably arranged coaxially with one of the rollers and is urged to rotate above the one roller by an elastic body, the rotary cover descends and the other roller is lowered. When they come into contact, they are rotated and retracted. Therefore, the sheet is supported by the rotating cover while being stored in the sheet stacking unit, and does not come into contact with one of the rollers that are constantly rotating and rub against it.

In the image forming apparatus provided with the above-mentioned discharged sheet stacking device, the sheets stored for performing the processing such as stapling are not rubbed by the one roller which is constantly rotating, and therefore the image forming apparatus The quality can be maintained.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described with reference to FIGS.

[First Embodiment] FIGS. 4 to 8 are front sectional views of a laser beam printer which is an image forming apparatus equipped with a discharge sheet stacking apparatus 600 according to the first embodiment of the present invention.

First, a printer device represented by a laser beam printer will be described.

The printer device 100 is independently connected to a computer or a network such as a LAN, and the information sent from these devices is imaged by a predetermined image forming process in an image forming section 102 or the like. Is a device for forming a sheet and discharging it.

The first sheet feeding device 200 includes a sheet cassette 201 that accommodates a plurality of sheets P and is removable,
A sheet separating / feeding unit 202 that separates the sheets P stored in the sheet cassette one by one according to a predetermined sheet supply signal and conveys the separated sheets to the printer body 101. Also,
The sheet feeding device 200 includes second and third sheet feeding devices 300 and 4 which are located in a lower layer so that they can be stacked and used.
Sheet guide portion 2 for conveying the sheet P from 00
Has 03.

The second sheet feeding device 300, like the first sheet feeding device 200, conveys the sheet P from the sheet cassette 301 for accommodating the sheets P, the sheet separating / feeding section 302, and the third sheet feeding device. Guide part 3
And 03.

The third sheet feeding device 400 includes the first and second sheets.
The sheet feeding device 200 has a configuration similar to that of the sheet feeding devices 200 and 300, and the sheet cassette 401 of the third sheet feeding device 400.
Is configured so that more sheets P can be stored than the sheet cassette 201 of the first and second sheet feeding devices 200 and 300. Further, the printer body 1 is formed to have a long length so that a long sheet can be used.
The rear end projects more than 01.

These sheet feeding devices 200, 300,
All of 400 are positioned with respect to each other by unillustrated positioning pins and fitting holes of the same shape, and when they are stacked, they are electrically coupled by a connector, and the printer 100 and the upper and lower sheet cassettes 201 are automatically connected. Three
The printer device 100 can be informed of the combined state of the printers 01 and 401.

Therefore, the user can select the number of stages and the capacity of the sheet cassette that suits the specification environment from many variations.

The duplex unit 500 includes the printer device 10.
It is configured to be mounted on the printer device 100 from the left side in the drawing along the guide shape formed in 0.

Printer device 100 and duplex unit 50
No. 0 is also electrically connected by the connectors provided on both sides, power supply and communication from the printer device 100 to the duplex unit 500 is possible, and the connection state can be confirmed on the printer device 100 side. There is.

The ejected sheet stacking device 600 is a part of the printer device 100, and the sheets sent from the printer device 100 are conveyed face down through the vertical conveyance portion 700 and the extension guide portion 800 for each predetermined job. It is a device for bundling sheets and stapling them at one place or at a plurality of places for discharge and stacking, or simply discharging and stacking face down.

Next, the discharged sheet stacking device 600 will be described along the conveying path of the sheets P.

The sheet P selectively supplied from desired sheet cassettes 201, 301, 401 by a predetermined print signal transfers an image in the printer apparatus 100 by an image forming process with the image forming surface facing upward. The image transferred by the fixing unit 120 is then fixed on the sheet P.

The sheet on which the image is fixed is printed by the FD flapper 121 in response to a predetermined signal to the printer main body 101.
The sheet is selectively branched and conveyed to the FD sheet discharge section 125 prepared above the sheet or the duplex unit 500.

The sheet P branched and conveyed to the double-sided unit 500 operates the double-sided conveyance sensor lever 501.

If the conveyed sheet is an instruction for double-sided printing, the double-sided conveying roller 502 on the downstream side is driven to guide the sheet to the reverse conveying path 503. Next, the sheet P
After detecting that the rear end has passed through the double-sided conveyance sensor lever 501, the double-sided conveyance roller 502 is reversely driven at a predetermined timing. As a result, the sheet P is loaded into the double-sided loading path 504.
And is again conveyed to the printer 100 for double-sided image processing.

Next, the movement of the sheet P will be described.

The discharged sheet stacking device 600 has been initialized. When the sheet P carried into the double-sided unit 500 operates the double-sided conveyance sensor lever 501, this sensor drives the conveyance roller 502 on the downstream side at a predetermined timing, and outputs a signal to the discharged sheet stacking device 600 to discharge the discharged sheet. The plunger 611 of the flapper solenoid 610 shown in FIG. 6 provided in the loading device 600 is pulled. A lever 612 is rotatably attached to the plunger 611. Since this lever 612 is supported by the rotating shaft 613, the link levers 711 and 811 are pushed up to rotate the flapper 505 provided in the duplex unit 500. The conveyance path is switched by the flapper 505, and the sheet P is carried into the discharged sheet stacking apparatus 600 via the extension guide 800 and the vertical conveyance unit 700.

As shown in FIGS. 4 and 5, the vertical transport unit 700 is set up at a position where the sheet cassette 401 protruding from the printer apparatus main body 101 has escaped, so that from the exterior surface of the printer apparatus main body 101, It is a little far away. The sheet that has passed through the extension guide 800 and is conveyed to the vertical conveyance unit 700 is provided on the discharged sheet stacking device 600 by the vertical conveyance roller 701 and the conveyance roller 702 that is rotatably biased by the vertical conveyance roller 701. The alignment carry-in roller 601 and the alignment carry-in roller 601 carry the sheet into the sheet aligning unit.

At this time, the sheet on which the image is formed with the image forming surface facing up in the printer apparatus 100 is carried in under the printer apparatus main body 101 and carried in, so that the image forming surface is face-down facing downward. Is brought in.

Further, the pair of aligning carry-in rollers 601, 60
A matching carry-in sensor 603 is provided on the upstream side of the nip of No. 2. The sensor 603 detects the timing at which the sheet is carried in and the timing at which the rear edge of the sheet comes out, and after a predetermined time, the lateral registration aligning plate 622, which will be described later, operates the shutter 632, and the sheet. It also detects jams.

The sheet P conveyed by the pair of alignment carry-in rollers 601 and 602 is guided by the upper guide 621 and the alignment table 620, and the pair of alignment rollers 601 and 6 is provided.
02 and the vertical alignment belt 631 cause the leading edge of the sheet to abut against the leading edge stopper portion 633 provided on the sheet stopper 632. The distance from the pair of alignment discharge rollers 601 and 602 to the leading end stopper portion 633 is set shorter than the minimum length of the sheet handled by this sheet discharge device. Figure 4,
The sensor 634 of FIG. 5 is a sensor for detecting the presence or absence of the sheet P on the alignment table 620.

When the discharged sheet stacking device 600 does not receive the stapling instruction, the bundle conveying roller 640 moves down. Then, the sheet stopper is opened, and the bundle conveying roller 640 is driven. Then, the sheet discharge roller 645 is lowered to rotate the bundle conveying roller 640.
And the sheet is discharged to the stack unit 650.

The vertical alignment belt 631 continues to rotate in the direction for pulling in the sheet even after the leading edge of the sheet hits the stopper portion 633, but the conveying force is set to be weak, so that the sheet may buckle, Seat stopper 633
It doesn't push open.

When the ejected sheet stacking device 600 receives a stapling instruction, the rear end of the sheet P passes through the aligning carry-in roller 601 and the leading end hits the stopper portion 633. The alignment motor 623 drives the lateral registration alignment plate 622 to align the conveyed sheet P in the horizontal direction. The lateral registration aligning plate 622 is retracted to a position retracted by a predetermined amount from the sheet width direction (direction orthogonal to the sheet transport direction) at the sheet carry-in position, and the transported sheet P can be moved to a position slightly narrower than the sheet width. As described above, the lateral registration motor 623 is controlled. When the lateral registration aligning plate 622 is pushed in to a position narrower than the sheet width, the sheet is bent, and the reaction force is applied to the sheet pressing portion of the lateral registration aligning plate 622.

The lateral registration matching plate 622 meshes with the driving pinion gear provided on the lateral registration motor 623,
A play gap is provided in the seat width direction between the rack gear receiving the driving force and the lateral registration aligning plate 622.
A spring member (not shown) that absorbs the reaction force of the sheet is constantly urged within the range of the gap to a position that narrows the width of the sheet. The clearance of this play is set so that the lateral registration plate 622 is narrower than the sheet width and larger than the pushing amount. Therefore, when the reaction force of the sheet exceeds a predetermined value, the sheet registration portion of the lateral registration plate 622 moves the sheet alignment part It loses the reaction force and stays within the width of the seat within the play gap. The sheet P can be aligned by applying a predetermined pressure from the side surface.

The sheet bundle thus aligned and aligned in the predetermined number of sheets aligning section enters the step of stapling by the stapling unit 670 shown in FIG.

Here, since the movement of the stapling portion differs between the case where there is one stapling point and the case where there are plural stapling points, each case will be described.

FIG. 7 is a plan view of the alignment table 620 on which the sheets P are stacked.

The stapling unit 670 is arranged in the conveyance direction (arrow direction) with respect to the sheets stacked with the image forming surface downward.
7 is fixed at the upper right position in FIG. 7, and the corner of the sheet bundle can be bound at that position.

Therefore, in stapling at one corner of the aligned sheet bundle, first, the lateral registration aligning plate 622 is pushed narrower than the sheet width, and the sheet width position is changed from the aligning position pressed against the reference plate 624. Then, the lateral registration matching motor 623 is kept magnetized at this position. After that, the stapling unit 670 is driven to start the stapling operation, and the sheets are bound.

The sheet bundle bound by the staple unit 670 is first retracted to the open position by the lateral registration aligning plate 622, and then lowered by the upper bundle conveying roller 640 so that the sheet bundle can be conveyed by a predetermined rotating arm. , The lower bundle conveying roller 641 provided on the alignment table 620 side,
Nip a bundle of sheets. After that, the sheet stopper 632
Is released, and the bundle conveying rollers 640 and 641 are driven in the rotational direction to be discharged and stacked on the stack portion 650.
At this time, normally, the sheet discharge roller 645 which is retracted by an elevating mechanism (not shown) also descends to convey and discharge the sheet bundle. The discharge roller 645 and the bundle conveying rollers 640 and 641 are always released because their driving is not released even when they are in the retracted position.

When stapling the aligned sheet bundle at two or more places, as shown in FIG. 8, the staple is not placed at the corners of the sheet bundle but at a place distant from the center of the sheet length by a predetermined position. The stapling position is different from staple. Therefore, the control method also differs between the case where there is one corner and the case where there are a plurality of corners. When stapling at a plurality of locations, the sheet stopper is opened and the sheet bundle is conveyed to the stapling location for stapling.

First, the lateral registration aligning plate 622 is returned from the position pushed into the sheet width to the sheet width position so that it is hardly pressed, and then the upper bundle conveying roller 640 is lowered to face the sheet bundle while sandwiching it. It is sandwiched by the bundle conveying backup roller 641. Next, the seat stopper 6
32 is opened, and the bundle conveying rollers 640 and 641 are driven to convey the sheet bundle to a predetermined position. In this position,
Although the conveying rollers are stopped, the stapling process is performed while the sheet bundle is pressed and constrained by the conveying rollers.

After the second position, stapling is performed in the first position.
After stapling the position, the bundle conveying rollers 640 and 641 are conveyed to a predetermined position, and similarly, the bundle conveying rollers are nipped and stopped, and the stapling operation is repeated.

After the stapling process is completed, the lateral registration aligning plate 622 is expanded from the sheet width position, and the bundle conveying roller pair 6
40 and 641 are driven, and the sheet discharge roller 645 at the retracted position is moved down to the transportable position, and the transport bundle is transported and discharged and stacked on the stack unit 650.

4 and 5, the discharged sheet sensor flag 646 is a flag for detecting a jam of the sheet discharging portion.

In FIG. 3, the full load detection 660 detects that the discharged and stacked sheets reach a predetermined stacking height, and stacks more sheets to prevent the device from malfunctioning or damaging the stacked sheets. I am trying.

Next, the main part of the present invention will be described.

FIG. 1 is a partial cross-sectional view around the alignment table 620 which is a sheet stacking unit. 2 and 3 are cross-sectional views of the matching table 620 in the width direction. In FIG. 1, the state shown by the solid line shows the state where the sheets P are stacked (stored) on the alignment table 620, and the state shown by the chain double-dashed line shows the state where the bundled sheets are discharged. There is.

Guide member 635 which is a sheet receiving member
On both sides of the bundle conveying roller 641 and on the alignment table 6
A pair of link pieces is provided below 20 in such a manner that it can be tilted in the vertical direction by a fulcrum shaft 635a. One end 635c of the guide member 635 contacts the sheet stopper 632, and the other end 635b contacts the alignment table 620. An intermediate portion 635d between the fulcrum shaft 635a and the other end 635b of the guide member 635 is formed in a substantially arc shape so as to easily receive and eject the sheet P, and penetrates the through hole 625 of the alignment table 620. Then, it slightly protrudes above the lower bundle conveying roller 641.

When the sheet P is fed onto the alignment table 620, the sheet P passes over the intermediate portion 635d of the guide member, comes into contact with the leading end stopper portion 233 of the sheet stopper 632, is supported by the guide member 635, and is aligned with the alignment table 62.
0 is loaded on top. The lower-bundle conveying roller 641 is always rotating, but does not contact the sheet and does not damage the sheet or damage an image formed on the sheet.

In particular, when the lower bundle conveying roller 641 made of rubber is used to easily convey the sheet, if the sheet is rubbed, the sheet and the image are easily damaged, but the sheet is not in contact with the sheet. It does not damage the sheet or the image without impairing the carrying force.

When a predetermined number of sheets are stacked on the alignment table 620 and the stapling process is completed, the sheet stopper 632 is clocked by an actuator 680 such as a motor or a plunger to a position indicated by an imaginary line about the fulcrum shaft 632a. The tip stopper portion 633 is swung in the direction to sink the tip stopper portion 633 below the alignment table 620. At the same time, the guide member 635 causes the sheet stopper 63 to
By the rotation of 2, the fulcrum shaft 635a is rotated counterclockwise to a position indicated by an imaginary line, and the intermediate portion 635d moves below the lower bundle conveying roller 641.
When the guide member 635 is rotated counterclockwise, the upper bundle conveying roller 640 descends, penetrates the through hole 627 of the sheet lifting suppressing plate 626, and the lower bundle conveying roller 64.
With 1, the sheet bundle is nipped. The sheet bundle is carried out by the bundle conveying roller pairs 640 and 641.

[Second Embodiment] A guide member 635 which is a sheet receiving member shown in FIG. 9 is a compression spring 6 which is an elastic body interposed between one end 635c and an alignment table 620.
The link piece is always urged to rotate clockwise by 36, and the intermediate portion 635d slightly projects upward from the lower bundle conveying roller 641.

When the sheet P is fed onto the alignment table 620, it passes over the intermediate portion 635d of the guide member, abuts on the leading end stopper portion 233 of the sheet stopper 632, is supported by the guide member 635, and is aligned on the alignment table 62.
0 is loaded on top. The lower-bundle conveying roller 641 is always rotating, but does not contact the sheet and does not damage the sheet or damage an image formed on the sheet.

When a predetermined number of sheets are stacked on the alignment table 620, stapling processing is performed, the upper bundle conveying roller 640 is lowered, and the sheet bundle and the guide member 635 are pushed down against the compression spring 636, and the lower portion is lowered. Bundle conveying roller 64
With 1, the sheet bundle is nipped. The sheet bundle is carried out by the bundle conveying roller pairs 640 and 641.

The intermediate portion 63 of the guide member 635 to which the rotational biasing force of the spring 636 is constantly applied to the sheet bundle.
5d are in contact with each other, but the elasticity of the spring 636 is set to such an extent that the guide member does not damage the sheet, and thus the sheet bundle is rubbed by the guide member 635 and damaged when discharged. There is almost no such thing.

Although the guide members 635 described above are arranged on both sides of the lower bundle conveying roller 641, they may be arranged on one side. However, in this case, it is necessary to increase the protrusion amount of the guide member to support the lower bundle conveying roller 641 so that the sheet does not come into contact with the lower bundle conveying roller 641.

[Third Embodiment] A roller cover means 690 shown in FIGS. 10 and 11 includes a rotary cover 638 arranged coaxially with a rotary shaft 641a of a lower bundle conveying roller 641.
The lower bundle conveying roller 641 is composed of a tension spring 637 that is an elastic body that urges the upper portion of the lower bundle conveying roller 641 to come into contact with the sheet P.

Normally, the rotary cover 638 is formed in a shape such that the "U" shape is inverted when viewed from the left side in FIG. 10, accommodates and covers the lower bundle conveying roller 641, and is fed onto the alignment table 620. It supports the sheet P that came. The lower-bundle conveying roller 641 is always rotating, but does not contact the sheet and does not damage the sheet or damage an image formed on the sheet.

When a predetermined number of sheets are fed in, the stapling process is completed, and the leading end stopper portion 633 of the sheet stopper 632 is recessed downward from the alignment table 620,
The upper bundle conveying roller 640 moves down. The sheet bundle is sandwiched between the upper bundle conveying roller 640 and the rotation cover 638. When the upper bundle conveyance roller 640 rotates counterclockwise, the sheet bundle is sent in the discharge direction, and the conveyance cover 638 is rotated following the same direction (clockwise). The upper bundle conveying roller 640 continues to rotate, and the rotation cover 638
Comes out between the sheet bundle and the lower bundle conveying roller 641. After that, the sheet bundle is formed by a pair of bundle conveying rollers 640 and 64.
It is nipped with 1 and discharged. When the sheet bundle is discharged, the rotary cover 638 is pulled by the tension spring 637.
It returns to rotate, covers the upper portion of the lower bundle conveying roller 641, and prepares for the next sheet loading.

In any of the above embodiments,
The lower bundle conveying roller 641 does not move up and down, and the upper bundle conveying roller 64
However, when the lower-bundle conveying roller 641 is moved up and down, the sheets stacked on the aligning table are lifted and the alignment of the sheet bundle is destroyed, so that the unsightly sheets are stapled. This is to prevent bundling.

[0077]

According to the invention of claim 1, while the sheet is stored on the sheet stacking portion by the storing means, the sheet is supported by the sheet receiving member and does not come into contact with one of the rollers. For the purpose of simplifying the structure of the discharged sheet stacking device and reducing the cost, it may be damaged by being rubbed by the one roller that is constantly rotating without equipping a drive connecting / disconnecting means such as a clutch. Absent. Further, the image formed on the sheet is not damaged.

When the storing means is the sheet stopper and the sheet receiving member is the link piece interlocking with the sheet stopper as in the second aspect of the invention, the operation of the link piece is ensured and the sheet is stored. During that time, the sheet can be surely supported so as not to come into contact with one of the rollers, so that the sheet or the image can be prevented from being damaged.

If the sheet receiving member is a link piece protruding upward from one roller by the elastic body as in the third aspect of the invention, the sheet piece is pushed by the other roller and retracts. It is possible to reliably support the sheet and prevent it from contacting one of the rollers to prevent damage to the sheet or the image.

According to the fourth aspect of the present invention, if the rotary cover is urged to rotate above one of the rollers, the other cover is rotated and retracted, so that the rotary cover secures the sheet. It is possible to prevent the sheet or the image from being damaged by supporting it on one side so as not to contact one of the rollers.

According to the fifth aspect of the invention, the image forming apparatus is provided with the above discharge sheet stacking device, and therefore, after forming an image on the sheet, the sheet can be discharged while maintaining the quality of the image. it can.

[Brief description of drawings]

FIG. 1 is a front sectional view of a main part of a discharged sheet stacking device according to a first embodiment of the present invention.

FIG. 2 is a left side sectional view of FIG.

FIG. 3 is a diagram showing a state in which a sheet is sandwiched by a pair of sheet conveying rollers in FIG.

FIG. 4 is a front sectional view of the image forming apparatus of the present invention.

FIG. 5 is a front cross-sectional view of the discharged sheet stacking device according to the first embodiment of the present invention.

6 is a schematic perspective view of a link mechanism that links a duplex unit and a vertical transport unit in the image forming apparatus of FIG.

7 is a schematic plan view of a mechanism for stapling sheets in the discharged sheet stacking apparatus of FIG.

FIG. 8 is a schematic plan view in the case where stapling is applied to different places of the sheet in FIG.

FIG. 9 is a front sectional view of a main portion of a discharged sheet stacking device according to a second embodiment of the present invention.

FIG. 10 is a front sectional view of a main part of a discharged sheet stacking device according to a third embodiment of the present invention.

11 is a front cross-sectional view of a state where a sheet is sandwiched by a pair of sheet conveying rollers in FIG.

[Explanation of symbols]

P sheet 100 printer device (image forming device) 102 image forming unit 600 discharge sheet stacking device 620 alignment table (sheet stacking unit) 632 sheet stopper (storing unit) 633 leading end stopper unit 635 guide member (sheet receiving member) 636 compression spring ( Elastic body 637 Tension spring (elastic body) 638 Rotating cover (sheet receiving member) 640 Bundle transport roller pair, upper bundle transport roller (sheet transport roller pair) 641 Bundle transport roller pair, lower bundle transport roller (sheet transport roller pair) 690 roller cover means

Continuation of the front page (56) Reference JP-A-6-24630 (JP, A) JP-A-9-221259 (JP, A) JP-A-9-221258 (JP, A) JP-A-2-233459 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 31/30 B42C 1/10 B65H 37/04

Claims (5)

(57) [Claims] 1. A sheet stacking unit capable of stacking a plurality of sheets, a storage unit configured to store the sheets on the sheet stacking unit, and a pair of sheet conveying rollers configured to sandwich and discharge the sheet on the sheet stacking unit, In the discharge sheet stacking device, wherein one roller of the pair of sheet conveying rollers is located on the side of the sheet stacking portion, and the other roller can be brought into contact with and separated from the one roller from above, The sheet is positioned above and supports the sheet on the sheet stacking unit, the storage unit releases the storage of the sheet, and retreats when the other roller descends to bring the sheet into contact with the one roller. A discharged sheet stacking device comprising a sheet receiving member. 2. The storage means is a sheet stopper for projecting and retracting the sheet stacking portion to receive a sheet, the sheet receiving member is a rotatable link piece linked with the sheet stopper, and the link piece is the sheet. The discharged sheet stacking apparatus according to claim 1, wherein when the stopper projects upward from the sheet stacking section, the stopper projects above the one roller, and when the sheet stopper is retracted into the sheet stacking section, the sheet retracts. 3. The sheet receiving member is a link piece that is urged to rotate upward by the elastic body in a direction projecting upward from the one roller, and the link piece is pressed by the other roller that descends and retracts. The discharged sheet stacking device according to claim 1. 4. The sheet receiving member is a rotary cover that is rotatably arranged coaxially with the one roller and is urged to rotate above the one roller by an elastic body. The discharged sheet stacking device according to claim 1, wherein the other descending roller is rotated by contact with the other roller and retracts. 5. An image forming section for forming an image, and 1.
An image forming apparatus, comprising: the discharge sheet stacking device according to any one of items 1 to 4.