JPH11236161A - Discharged sheet loading apparatus, and image forming apparatus provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an image on a sheet from being damaged by one continuously rotating roller among a pair of sheet carrying rollers in a discharged sheet loading apparatus. SOLUTION: A discharged sheet loading apparatus is provided with a sheet loading part 620 capable of loading a plurality of sheets P, a storage means 632 to store the sheets on the sheet loading part, and a pair of sheet carrying rollers 640, 641 to hold and discharge the sheet on the sheet loading part, one roller 641 of a pair of sheet carrying rollers is located on the sheet loading part side, the other roller 640 is attachable/detachable to/from one roller from an upper part, and a sheet receiving member 635 which is projected upward of one roller, supports the sheet on the sheet loading part, releases the storage of the sheet by the storage means, and is retracted to bring the sheet into contact with one roller when the other roller is lowered, is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharged sheet stacking apparatus for temporarily stopping a sheet for two-sided image processing, stapling, and the like, and then discharging the sheet, and a printer and a copier equipped with the apparatus. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, network environments using personal computers and the like have been developed. An image forming apparatus placed in such a network environment is shared by a plurality of users and is used in various ways. These requests include, for example, double-sided image processing and stapling processing.

In order to respond to such demands, a printer as an image forming apparatus is provided with a discharge sheet stacking device. This apparatus is capable of performing a stapling process by temporarily stopping and waiting a sheet in a sheet conveying path.

[0004] The sheet conveyed in the vertical conveying section is received by the discharge sheet stacking device by the pair of alignment carry-in rollers, and is guided to the upper surface of the alignment table as the sheet stacking section. Then, the sheet is brought into contact with the leading end stopper portion of the sheet stopper, and is stacked on the alignment table.

[0005] When a predetermined number of sheets are stacked on the alignment table to form a bundle, the sheets are aligned in the feed direction and a direction perpendicular thereto, and are sandwiched between a pair of sheet transport roller pairs. Then, the sheet is conveyed and discharged from the discharge sheet stacking device in a bundle state when the conveyance path is released by the leading end stopper rotating and retracting.

[0006]

By the way, in order to simplify the structure and reduce the cost, the above-mentioned discharge sheet stacking device has a clutch or the like attached to a lower bundle transport roller disposed below the bundle transport roller pair. Is not provided.

Therefore, the lower bundle transport roller continues to rotate while supporting the sheet abutting on the leading end stopper from below. Also, the lower transport roller transports the sheets in a bundle,
It is arranged at a height substantially flush with the upper surface of the alignment table.

As described above, since the lower bundle transport roller continues to rotate at a position substantially flush with the upper surface of the alignment table, the lower bundle transport roller keeps rubbing the lower surface of the lowest sheet abutting on the leading end stopper. .

Therefore, the unloading 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,
It is an object of the present invention to provide a discharged sheet stacking device for preventing a sheet surface from being damaged or damaging an image formed on the sheet, and an image forming apparatus including the discharged sheet stacking device.

[0011]

The above object is attained by the following discharged sheet stacking device.

A sheet stacking unit capable of stacking a plurality of sheets; a storage unit for storing the sheets on the sheet stacking unit; and a sheet conveying roller pair for sandwiching and discharging the sheets on the sheet stacking unit. In a discharge sheet stacking device in which one roller of the sheet conveying roller pair is located on the sheet stacking portion side and the other roller can be separated from and separated from above with respect to the one roller, the roller is positioned above the one roller. A sheet receiver that supports the sheet on the sheet stacking portion and releases the sheet from being stored, and retracts when the other roller is lowered to contact the sheet with the one roller; A member is provided.

The storage means is a sheet stopper which protrudes and retracts from the sheet stacking portion to receive a sheet, and the sheet receiving member is a rotatable link piece interlocked with the sheet stopper. When the sheet stopper protrudes upward from the sheet stacking portion, it protrudes upward from the one roller, and retreats when the sheet stopper enters the sheet stacking portion.

The sheet receiving member is a link piece which is urged by an elastic body to rotate in a direction protruding above the one roller, and the link piece is pressed by the other roller descending and retracts.

[0015] The sheet receiving member is a rotary cover that is rotatably disposed coaxially with the one roller and is urged by an elastic body to rotate above the one roller.
The rotating cover is rotated and retracted by the contact of the other roller descending.

The above object is also achieved by an image forming apparatus provided with an image forming section for forming an image and the discharged sheet stacking device according to any one of the above.

[Operation] The sheet fed from outside is
To receive a staple process or the like, the sheet is stored on the sheet stacking unit by the storage unit and is supported by the sheet receiving member.
Thereafter, when the storage is released and the other roller descends, the sheet is transferred from the retracted sheet receiving member to one of the rollers, and is discharged by being sandwiched between the sheet conveying roller pair.

Accordingly, while the sheet is stored in the sheet stacking section, the sheet is supported by the sheet receiving member, and does not come into contact with one of the rotating rollers to be rubbed.

If the storage means is a sheet stopper for receiving and receiving the sheet by protruding and retracting from the sheet stacking section, and if the sheet receiving member is a rotatable link piece interlocked with the sheet stopper, the link piece is such that the sheet stopper is located above the sheet stacking section. When the sheet stopper protrudes above the one roller, the sheet is supported, and when the sheet stopper enters the sheet stacking portion, the sheet stopper is retracted and reliably transferred to the one roller. Therefore, while the sheet is stored in the sheet stacking section, the sheet is supported by the link piece, and does not come into contact with one of the rotating rollers to be rubbed.

If the sheet receiving member is a link piece that is urged by an elastic body to rotate in a direction protruding above one roller, the link piece is pressed by the other roller that descends and retreats without fail, and the sheet is retracted. Transfer to one roller. Therefore, while the sheet is stored in the sheet stacking section, the sheet is supported by the link piece, and does not come into contact with one of the rotating rollers to be rubbed.

When the sheet receiving member is a rotatable cover that is rotatably arranged coaxially with one of the rollers and is urged to rotate above one of the rollers by an elastic body, the rotatable cover is moved downward by the other roller. It is rotated and retracted by contact. Therefore, while the sheet is stored in the sheet stacking section, the sheet is supported by the rotating cover and does not come into contact with one of the rotating rollers to be rubbed.

In the image forming apparatus provided with the discharged sheet stacking device, the sheet stored for performing the processing such as stapling is not rubbed by the one of the constantly rotating rollers. Quality can be maintained.

[0023]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This 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 a first embodiment of the present invention.

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

The printer device 100 is connected to a computer alone, or to a network such as a LAN, and transmits information sent from these devices to an image forming unit 102 or the like according to a predetermined image forming process. This is a device that forms a sheet and discharges it.

The first sheet feeding device 200 includes a detachable sheet cassette 201 for accommodating a plurality of sheets P,
A sheet separation / supply 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 sheets P to the printer main body 101. Also,
The sheet feeding device 200 includes second and third sheet feeding devices 300 and 4 located in lower layers so that the sheet feeding device 200 can be used in a stacked state.
Sheet guide section 2 for conveying the sheet P from 00
03.

The second sheet supply device 300 is, like the first sheet supply device 200, a sheet cassette 301 for storing sheets P, a sheet separation / supply unit 302, and a sheet for conveying sheets P from the third sheet supply device. Guide part 3
03.

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

These sheet feeding devices 200, 300,
400 are mutually positioned by a positioning pin and a fitting hole (not shown) of the same shape, and are electrically connected by a connector when they are overlapped with each other, so that the printer device 100 and the upper and lower sheet cassettes 201, 3
01 and 401 so that the printer device 100 can know the connection state.

Therefore, the user can select the number of sheets and the capacity of the sheet cassette suitable for the specification environment from many variations.

The double-sided unit 500 includes the printer 10
It is configured to be mounted on the printer device 100 from the left in the figure along the guide shape formed at 0.

Printer device 100 and duplex unit 50
0 is also electrically connected by connectors provided on both sides, so that power can be supplied to the duplex unit 500 and communication can be performed from the printer apparatus 100, and the connection state can be confirmed on the printer apparatus 100 side. I have.

The discharge sheet stacking apparatus 600 is a part of the printer apparatus 100 and receives a sheet sent from the printer apparatus 100 face down through a vertical conveyance section 700 and an extension guide section 800 for each predetermined job. This is a device for stacking sheets and stapling them at one place or a plurality of places for discharge and stacking, or simply discharges and stacks face down.

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

Sheets P selectively supplied from desired sheet cassettes 201, 301, and 401 in accordance with a predetermined print signal are transferred in a printer apparatus 100 by an image forming process with an image forming surface facing up. Then, the image transferred by the fixing unit 120 is fixed to the sheet P.

The sheet on which the image is fixed is sent to the printer main body 101 by the FD flapper 121 according to a predetermined signal.
Is selectively branched and conveyed to the FD sheet discharge unit 125 prepared at the upper part of the printer.

The sheet P branched and transported to the duplex unit 500 operates the duplex transport 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, sheet P
After detecting that the rear end has come out of the double-sided conveyance sensor lever 501, the double-sided conveyance roller 502 is driven to rotate in reverse at a predetermined timing. As a result, the sheet P is loaded into
, And conveyed again to the printer device 100 to perform 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 conveyed to the duplex unit 500 operates the duplex transport sensor lever 501, the sensor drives the transport roller 502 on the downstream side at a predetermined timing, and outputs a signal to the discharged sheet stacking device 600 to output 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, it pushes up the link levers 711 and 811 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 device 600 via the extension guide 800 and the vertical conveyance unit 700.

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

At this time, the sheet on which the image is formed with the image forming surface facing upward in the printer device 100 is wrapped under the printer device main body 101 and is carried in, so that the image forming surface is facing down, so-called face-down. It is carried in.

Further, the pair of matching carry-in rollers 601, 60
An alignment carry-in sensor 603 is provided upstream of the second nip. The sensor 603 detects a timing at which the sheet is carried in or a timing at which the trailing edge of the sheet comes off, and after a predetermined time, activates a lateral registration matching plate 622 described later, activates a shutter 632, and further operates the sheet. Or jam detection.

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 is aligned with the pair of alignment rollers 601 and 6.
02 and the vertical alignment belt 631, the leading end of the sheet abuts on a leading end 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 633 is set to be shorter than the minimum length sheet handled by this sheet discharge device. FIG.
The sensor 634 in 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 apparatus 600 has not received the stapling instruction, the bundle conveying roller 640 moves down. Then, the sheet stopper is opened, and the bundle conveying roller 640 is driven. Thereafter, the sheet discharge roller 645 is lowered, and the rotating bundle conveying roller 640 is rotated.
The sheet is discharged to the stack unit 650 in coordination with the above.

Although the vertical alignment belt 631 continues to rotate in the direction of pulling in the sheet even after the leading end of the sheet has hit the stopper portion 633, the conveying force is set to be weak, so that the sheet may buckle, Seat stopper 633
They do not push open.

When the discharged sheet stacking apparatus 600 receives the stapling instruction, the timing at which the rear end of the sheet P passes through the aligning / conveying roller 601 and the front end abuts against the stopper portion 633 is determined, and the horizontal registration as a stepping motor is performed. The alignment motor 623 drives the horizontal registration alignment plate 622 to perform the horizontal alignment of the loaded sheet P. The horizontal registration alignment plate 622 is retracted to a position retracted by a predetermined amount from the sheet width direction (a direction orthogonal to the sheet transport direction) at the sheet loading position, and can move the transported sheet P to a position slightly smaller than the sheet width. Is controlled by the lateral registration motor 623 as described above. When the lateral registration plate 622 is pushed down to a position narrower than the sheet width, the sheet bends, and the reaction force is applied to the sheet pressing portion of the lateral registration plate 622.

The lateral registration aligning plate 622 meshes with a driving pinion gear provided on the lateral registration motor 623,
A play gap is provided in the sheet width direction between the rack gear and the rack gear receiving the driving force.
A spring member (not shown) that absorbs the reaction force of the sheet is constantly urged to a position where the width of the sheet is narrowed within the gap. The gap of the play is set to be larger than the sheet width by the lateral registration alignment plate 622, so that when the reaction force of the sheet becomes more than a predetermined value, the sheet alignment portion of the horizontal registration alignment plate 622 is The reaction force remains at the width of the sheet within the play gap. A predetermined pressure can be applied from the side surface of the sheet P for alignment.

The sheet bundle that has been aligned as described above and aligned with the predetermined number of sheets aligning unit enters a step of being stapled by the staple unit 670 shown in FIG.

Here, the movement of the stapling portion is different between the case where the number of staples is one and the case where the number of staples is plural. Therefore, each case will be described.

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

The staple unit 670 transports the sheet stacked with the image forming surface downward (in the direction of the arrow).
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, when stapling one corner of the aligned sheet bundle, first, the horizontal registration alignment plate 622 is pushed in narrower than the sheet width, and the sheet registration position is shifted from the alignment position pressed against the reference plate 624 to the sheet width position. The horizontal registration motor 623 is maintained in a demagnetized state at this position. Thereafter, the staple unit 670 is driven to enter a staple operation, and the sheets are bound.

The sheet bundle bound by the staple unit 670 is first retracted to the open position by the horizontal registration aligning plate 622, and lowered by the upper bundle transport roller 640 so that the sheet bundle can be transported by a predetermined rotating arm. And the lower bundle transport roller 641 provided on the alignment table 620 side.
Nip the sheet bundle. Then, the sheet stopper 632
Is released, and the bundle conveying roller pair 640, 641 is driven in the rotational direction, and is discharged and stacked on the stack unit 650.
At this time, normally, the sheet discharge roller 645 evacuated by a lifting mechanism (not shown) also descends, and conveys and discharges the sheet bundle. The discharge roller 645 and the bundle transport rollers 640 and 641 are constantly rotating because their driving is not released even when they are at the standby position.

When two or more staples are stapled in the aligned sheet bundle, as shown in FIG. 8, the stapling is performed not at the corner of the sheet bundle but at a position distant from the center of the sheet length by a predetermined position. The stapling position is different from the stapling position. Therefore, the control method is different between a single corner and a plurality of corners. When stapling at a plurality of locations, the sheet stopper is opened and the sheet bundle is conveyed to the staple location and stapled.

First, the horizontal registration plate 622 is returned from the position where it is pushed in with respect to the sheet width to the sheet width position so that it is hardly pressed, and then the upper bundle transport roller 640 is lowered to oppose the sheet bundle. With the bundle transport backup roller 641. Next, sheet stopper 6
Then, the sheet bundle 32 is released, and the bundle conveying rollers 640 and 641 are driven to convey the sheet bundle to a predetermined position. At this predetermined position,
Although the conveying rollers are stopped, the staple process is performed while the sheet bundle is constrained by applying the pressure of the conveying rollers.

The stapling after the second position is performed in the first position.
After the stapling of the position, the bundle transport roller pair 640, 641 is transported to a predetermined position, and then the bundle transport rollers are similarly stopped while being nipped, and the stapling operation is repeated.

After the stapling process is completed, the horizontal registration aligning plate 622 is spread from the sheet width position, and
While driving the sheets 40 and 641, the sheet discharge roller 645 at the retreat position is lowered to the transportable position, and the transport bundle is transported and discharged and stacked on the stack unit 650.

4 and 5, a discharge sheet sensor flag 646 is a flag for detecting a jam in the sheet discharge section.

In FIG. 3, the full load detection 660 detects that the discharged stacked sheets have reached a predetermined stacking height, and further stacks the sheets so as not to damage the apparatus or damage the stacked sheets. Like that.

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

FIG. 1 is a partial sectional view around the alignment table 620 which is a sheet stacking section. FIGS. 2 and 3 are cross-sectional views of the alignment table 620 in the width direction. In FIG. 1, a state indicated by a solid line indicates a state in which sheets P are stacked (stored) on the alignment table 620, and a state indicated by a two-dot chain line indicates a state in which a bundle of sheets is discharged. It is.

Guide member 635 serving as a sheet receiving member
Are on both sides of the bundle transport roller 641 and the alignment table 6
A pair of link pieces arranged below the base 20 so as to be vertically tiltable by a fulcrum shaft 635a. One end 635 c of the guide member 635 contacts the sheet stopper 632, and the other end 635 b 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 that the sheet P can be easily received and discharged, and penetrates through the through hole 625 of the alignment table 620. And slightly protrudes above the lower bundle transport roller 641.

When the sheet P is fed onto the alignment table 620, it passes over the intermediate portion 635 d of the guide member and abuts on the leading end stopper 233 of the sheet stopper 632, and is supported by the guide member 635, and
0 is loaded. Although the lower bundle transport roller 641 is constantly rotating, it 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 transport roller 641 made of rubber is used to facilitate the transport of the sheet, when the sheet is rubbed, the sheet or the image is easily damaged. The sheet and the image are not damaged without impairing the conveying 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 moved clockwise by the actuator 680 such as a motor or a plunger to a position indicated by a virtual line around the fulcrum shaft 632a. In the direction, the tip stopper 633 is immersed below the alignment table 620. At the same time, the guide member 635 is
Due to the rotation of 2, the intermediate portion 635d is rotated counterclockwise around the fulcrum shaft 635a to a position indicated by a virtual line, and the intermediate portion 635d moves below the lower bundle transport roller 641.
When the guide member 635 is rotated in the counterclockwise direction, the upper bundle transport roller 640 descends, penetrates through the through-hole 627 of the sheet lift suppression plate 626, and
In step 1, the sheet bundle is nipped. The sheet bundle is carried out by a pair of bundle conveying rollers 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 intermediate portion 635d is a link piece that is constantly urged to rotate clockwise by the reference numeral 36 and the intermediate portion 635d slightly projects above the lower bundle transport roller 641.

When the sheet P is fed onto the alignment table 620, it passes over the intermediate portion 635 d of the guide member and abuts on the leading end stopper 233 of the sheet stopper 632, and is supported by the guide member 635, and
0 is loaded. Although the lower bundle transport roller 641 is constantly rotating, it 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, a stapling process is performed, the upper bundle transport roller 640 is lowered, and the sheet bundle and the guide member 635 are pushed down against the compression spring 636, and Bundle transport roller 64
In step 1, the sheet bundle is nipped. The sheet bundle is carried out by a pair of bundle conveying rollers 640 and 641.

The intermediate portion 63 of the guide member 635 to which the rotational urging force of the spring 636 is constantly applied is applied to the sheet bundle.
5d is in contact, but since the elasticity of the spring 636 is set to such a degree that the guide member does not damage the sheet, the sheet bundle is rubbed by the guide member 635 and is damaged when being discharged. There is almost no such thing.

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

[Third Embodiment] The roller cover means 690 shown in FIGS. 10 and 11 comprises a rotary cover 638 disposed coaxially with the rotary shaft 641a of the lower bundle transport roller 641;
The lower bundle transport roller 641 is constituted by a tension spring 637 which is an elastic body which urges the position above a portion in contact with the sheet P to rotate.

Normally, the rotary cover 638 is formed in a shape such that the “U” is inverted when viewed from the left side in FIG. 10, accommodates and covers the lower bundle transport roller 641, and is fed onto the alignment table 620. Sheet P that has come up. Although the lower bundle transport roller 641 is constantly rotating, it 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 have been fed and the stapling process has been completed and the leading end stopper 633 of the sheet stopper 632 has been lowered downward from the alignment table 620,
The upper bundle transport roller 640 descends. The sheet bundle is sandwiched between the upper bundle conveying roller 640 and the rotating cover 638. When the upper bundle transport roller 640 rotates counterclockwise, the sheet bundle is sent in the discharge direction, and the transport rotation cover 638 is rotated in the same direction (clockwise). The upper bundle transport roller 640 continues to rotate, and the rotation cover 638
Exits between the sheet bundle and the lower bundle conveying roller 641. Thereafter, the sheet bundle is transferred to the bundle transport roller pair 640, 64.
1 and is discharged. When the sheet bundle is discharged, the rotating cover 638 is moved by the tension spring 637.
It returns to rotate and covers the upper portion of the lower bundle transport roller 641 to prepare for the next sheet carry-in.

As described above, in any of the embodiments,
The lower bundle transport roller 641 does not move up and down, and the upper bundle transport roller 64
However, when the lower bundle transport roller 641 is moved up and down, the sheets stacked on the alignment table are lifted, and the alignment of the sheet bundle is broken, and in the stapling process, the sheets having poor appearance are stuck. This is to prevent the bundle.

[0077]

According to the first aspect of the present invention, while the sheet is stored on the sheet stacking unit by the storing means, the sheet is supported by the sheet receiving member so as not to contact one of the rollers. However, for the purpose of simplifying the structure of the discharge sheet stacking device and reducing the cost, without being equipped with a drive intermittent means such as a clutch, the roller may be damaged by being rubbed by the one roller that is always rotating. Absent. Further, the image formed on the sheet is not damaged.

When the storing means is a sheet stopper and the sheet receiving member is a link piece interlocked with the sheet stopper, the operation of the link piece is assured, and the sheet is stored. During this time, the sheet is securely supported and is prevented from being in contact with one of the rollers, thereby preventing damage to the sheet or the image.

If the sheet receiving member is a link piece protruding above one roller by an elastic body as in the third aspect of the present invention, the sheet piece is retracted by being pressed by the other roller. The sheet and the image can be prevented from being damaged by securely supporting the sheet and preventing the sheet from contacting one of the rollers.

If the rotating cover is urged to rotate above one roller as in the invention of the fourth aspect, the rotating cover is rotated by the descending other roller and retracted, so that the rotating cover securely holds the sheet. To prevent the sheet or image from being damaged by preventing the roller from contacting one of the rollers.

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

[Brief description of the drawings]

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

FIG. 2 is a left side sectional view of FIG. 1;

FIG. 3 is a diagram illustrating a state in which a sheet is sandwiched between a pair of sheet conveying rollers in FIG. 2;

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

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

FIG. 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. 4;

FIG. 7 is a schematic plan view of a mechanism for performing a stapling process on a sheet in the discharged sheet stacking device of FIG. 5;

FIG. 8 is a schematic plan view in a case where staple processing is performed on different positions of a sheet in FIG. 7;

FIG. 9 is a front sectional view of a main part of a discharged sheet stacking apparatus 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 FIG. 10 in a state where a sheet is sandwiched between a pair of sheet conveying rollers.

[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 (storage means) 633 Tip stopper 635 Guide member (sheet receiving member) 636 Compression spring ( Elastic body) 637 Extension 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

Claims (5)

[Claims] A sheet stacking unit capable of stacking a plurality of sheets; a storage unit configured to store the sheets on the sheet stacking unit; a sheet conveying roller pair for holding and discharging the sheets on the sheet stacking unit; A discharge sheet stacking device in which one roller of the sheet conveying roller pair is located on the sheet stacking unit side and the other roller can be separated from and separated from above the one roller from above, It is located above and supports the sheet on the sheet stacking section, the storing means releases the storing of the sheet, and retracts when the other roller is lowered to bring the sheet into contact with the one roller. An output sheet stacking device comprising a sheet receiving member. 2. The storage device according to claim 1, wherein the storage unit is a sheet stopper that protrudes and retracts the sheet stacking unit to receive the sheet, and the sheet receiving member is a rotatable link piece that is interlocked with the sheet stopper. 2. The discharge sheet stacking device according to claim 1, wherein the stopper protrudes upward from the one roller when the stopper protrudes upward from the sheet stacking unit, and retreats when the sheet stopper enters the sheet stacking unit. 3. 3. The sheet receiving member is a link piece which is urged by an elastic body to rotate in a direction protruding above the one roller, and the link piece is pressed by the other roller descending and retracted. The discharge sheet stacking device according to claim 1. 4. The sheet receiving member is a rotatable cover arranged rotatably coaxially with the one roller and urged to rotate above the one roller by an elastic body. 2. The discharged sheet stacking device according to claim 1, wherein the other roller descends and is rotated and retracted by contact. 5. An image forming section for forming an image, and an image forming section for forming an image.
An image forming apparatus, comprising: the discharged sheet stacking device according to any one of (1) to (4).