JP2002308507A - Sheet stacking device, sheet processing device with it and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet stacking device, a sheet processing device with it and an image forming device capable of preventing damage at an edge on a stacked sheet even when a tray is lifted or lowered. SOLUTION: This device is provided with a discharge tray 4 capable of lifting and towering while stacking the sheet, and a belt member 15 for regulating an end part of the sheet stacked on the discharge tray 4. The belt member 15 is movable along a lifting and lowering direction of the discharge ray 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet stacking apparatus capable of stacking sheets and moving up and down, a sheet processing apparatus having the same, and an image forming apparatus.

[0002]

2. Description of the Related Art In recent years, image forming apparatuses such as copiers, printers, and facsimile apparatuses have tended to be miniaturized, save space, increase productivity, and increase discharge capacity.

[0003] For this purpose, FIG.
The sheet processing apparatus 50 shown in FIG. 1 is combined, a plurality of sheets on which images have been formed are aligned, staple-stitched, etc., and then stacked on the discharge tray 51. The discharge tray 51 of the sheet processing apparatus 50 is installed in an inclined state similarly to the processing tray 52. This is to ensure the consistency of the sheet and to increase the return speed of the sheet due to its own gravity.

The discharge tray is inclined (steeply inclined) to save space in the horizontal direction and to increase the sheet return speed required for sheet processing. Further, the discharge tray 51 includes a belt member 53.
, And can be moved up and down by the rotation of the belt member 53. Each time a sheet bundle is stacked on the discharge tray 51, the uppermost surface of the sheet is detected by an upper surface detection sensor (not shown), and the tray is lowered by a predetermined amount, and in some cases thereafter, is raised by a predetermined amount to a predetermined position. stand by. When this operation is repeated to descend to the position detected by the lower limit sensor, the operation stops. At this time, the rear end of the sheet is regulated by the fixed sheet abutting surface 1.

[0005]

However, in the above conventional example, the sheets stacked on the discharge tray 51 are always kept in contact with the fixed sheet abutting surface at the rear end. By operation, the rear end of the sheet bundle
The sheet abuts against the sheet abutting surface 54, and there is a possibility that an edge flaw is generated at a position corresponding to the contact portion.

Particularly, when the discharge tray 51 is steeply inclined, FIG.
As shown in (b), assuming that the force with which the sheet S abuts against the sheet abutting surface 54 is N and the friction coefficient is μ, the rubbing resistance μN of the sheet increases. If the amount of lifting and lowering of the tray is increased in order to increase the capacity, the number and amount of vertical movements also increase, and the above problem is more likely to occur, which leads to deterioration of the sheet quality.

The present invention has been made to solve the above problems, and
An object of the present invention is to provide a sheet stacking apparatus which does not cause edge damage to stacked sheets even when a tray is moved up and down, a sheet processing apparatus including the same, and an image forming apparatus.

[0008]

In order to achieve the above object, a typical configuration according to the present invention comprises a lifting tray on which sheets can be loaded and lowered, and an end portion of the sheets loaded on the lifting tray. A sheet end abutting portion for regulating, and wherein the sheet end abutting portion is configured to be movable in the elevating direction of the elevating tray.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a sheet stacking apparatus according to an embodiment of the present invention will be described by exemplifying an image forming apparatus having the same.

[First Embodiment] FIG. 1 is an explanatory sectional view of a sheet processing apparatus mounted on an image forming apparatus main body.
Is a perspective view of a sheet processing apparatus having a sheet stacking apparatus, and FIG. 3 is an explanatory view of the sheet stacking apparatus during operation.

First, a schematic configuration of an image forming apparatus and a sheet processing apparatus will be described. In FIG. 1, a sheet conveying means and an image forming means (not shown) are provided in the image forming apparatus main body 1, and a predetermined image is formed on a conveyed sheet and discharged to a sheet processing apparatus. The image forming means may employ various recording methods such as an electrophotographic recording method and an ink jet recording method.

The sheet processing apparatus 2 is mounted on the side of the apparatus main body 1 and performs processing such as staple binding on a plurality of sheets (sheet bundle). The sheet processing apparatus 2 includes a processing tray 3 disposed on the upstream side in the sheet conveyance direction and a discharge tray 4 disposed on the downstream side. Sheets discharged from the main body discharge unit are processed by the processing tray 3. The paper is loaded on the discharge tray 4.

As described above, the sheet on which the predetermined image is formed by the image forming means is sent from the discharge unit 5 onto the processing tray 3, and the predetermined number of sheets are transferred one by one in the sheet conveying direction and the sheet width direction. Matching is performed. The alignment in the sheet conveyance direction is performed by the self-gravity of the sheet obtained from the inclination angle of each tray and the return roller 6, and the alignment in the sheet width direction is performed by sliding the alignment plate 7 in the sheet width direction.

When the staple binding mode is selected, the stapler unit 8 performs staple binding on the aligned sheet bundle. The sheet bundle that has been processed in this way is discharged onto the discharge tray 4 by, for example, a bundle pushing belt 9 and stacked.

The discharge tray 4 is installed in an inclined state like the processing tray 3. This is to ensure the consistency of the sheet and to increase the return speed of the sheet due to its own gravity.

As shown in FIG. 2, the discharge tray 4, which is an elevating tray, has a belt 11 stretched over pulleys 10a and 10b.
The pulley 10b is driven and rotated by the motor 12. Thus, when the motor 12 is driven, the rollers 13 provided on the discharge tray 4 are guided by the rails 14 provided on the sheet processing apparatus main body, and the discharge tray 4 moves up and down.

Each time a sheet bundle is stacked on the tray, the uppermost surface of the sheet is detected by an unillustrated upper surface detection sensor, and the discharge tray 4 is lowered by a predetermined amount, and in some cases, is raised by a predetermined amount and thereafter, is raised by a predetermined amount. Wait at the position. When this operation is repeated to descend to the position detected by the lower limit sensor, the operation stops. At this time, the sheet rear end is abutted against the sheet abutting portion and regulated.

In the apparatus according to the present embodiment, as shown in FIG. 2, the sheet abutting portion is constituted by an endless belt member 15. And this belt member 15
Is suspended between pulleys 16 and 17 and is rotatably held. The belt member 15 is given a predetermined tension, and is disposed inside the seat width. However,
The number is not limited, and one wide belt and a plurality of belts may be provided.

In the above configuration, as shown in FIG. 3, when the discharge tray 4 loaded with the sheet bundle S is lowered, the belt member 15 is subjected to a downward force of μN by the sheet bundle S (N: the sheet is a belt member). 15 Contact force, μ: coefficient of friction between seat and belt member). Therefore, pulleys 16 and 17
Rotates freely and the belt member 15 rotates as the discharge tray 4 descends. Similarly, when the discharge tray 4 moves up, the belt member 15 rotates accordingly.

As described above, the belt member 15, which is the abutting portion of the sheet bundle, rotates as the discharge tray 4 moves up and down, so that the sheet ends are not rubbed, and there is no risk of edge damage. .

As shown in FIG. 4, the surface of the belt member 15, which is the sheet abutting surface, may be knurled to form the irregularities 15a. In this way, the belt member 15 efficiently receives the force received from the sheet bundle,
The belt member 15 is easily linked with the vertical movement of the discharge tray 4. Therefore, it is possible to reliably prevent the belt member 15 and the rear end of the sheet bundle from slipping, and it is possible to more reliably prevent the edge of the sheet rear edge from being damaged.

[Second Embodiment] In the above-described embodiment, the belt member 15 is rotatably supported, and is rotated in conjunction with the elevation of the discharge tray 4 by the frictional force with the sheet. 6, the belt member 15 may be driven and rotated so that the discharge tray 4 is moved up and down.

FIG. 5 is a perspective view of the sheet processing apparatus according to the second embodiment, and FIG. 6 is a sectional view of the sheet processing apparatus. Explaining a portion different from the first embodiment in configuration, a pulley 16 around which a belt member 15 serving as a sheet abutting portion is attached is rotatably supported integrally with a shaft 18. A pulley 19 is attached to a tip end of the shaft 18, and a driving connection between the pulley 19 and the pulley 10 b is performed by a belt 20. And the pulleys 10b, 1
9 and 16 have the same diameter.

As a result, not only does the belt member 15 move up and down in conjunction with the elevating operation of the discharge tray 4, but also the elevating direction and speed become the same, so that the rear end of the sheet bundle and the sheet abutting surface are rubbed. It can be reliably prevented.

[0025]

As described above, according to the present invention, the rear end of the sheet bundle is
It can be prevented that the sheet abuts against the sheet abutting surface and the edge corresponding to the abutting portion is damaged and the quality of the sheet is impaired. As a result, the discharge tray can be steeply inclined, and it has become possible to meet user needs such as downsizing of the apparatus, saving space, increasing productivity, and increasing discharge capacity.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of a sheet processing apparatus mounted on an image forming apparatus main body.

FIG. 2 is an explanatory perspective view of a sheet processing apparatus having a sheet stacking apparatus.

FIG. 3 is an explanatory diagram at the time of operation of the sheet stacking device.

FIG. 4 is an explanatory diagram of a belt that has been knurled.

FIG. 5 is a perspective view illustrating a sheet processing apparatus according to a second embodiment.

FIG. 6 is an explanatory sectional view of a sheet processing apparatus.

FIG. 7 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 S ... Sheet 1 ... Image forming apparatus main body 2 ... Sheet processing device 3 ... Treatment tray 4 ... Discharge tray 5 ... Discharge unit 6 ... Return roller 7 ... Alignment plate 8 ... Stapler unit 9 ... Bunch push belts 10a and 10b ... Pulley 11 Belt 12 ... Motor 13 ... Roller 14 ... Rail 15 ... Belt member 16, 17 ... Pulley 18 ... Shaft 19 ... Pulley 20 ... Belt

Claims (7)

[Claims] An elevating tray capable of stacking and elevating the sheets, and a sheet end abutting portion for regulating an end of the sheets stacked on the elevating tray. A sheet stacking device configured to be movable in an elevating direction of an elevating tray. 2. The sheet stacking apparatus according to claim 1, wherein said sheet end abutting portion is constituted by a belt member. 3. The sheet stacking apparatus according to claim 2, wherein the belt member is rotatably supported by at least two pulleys. 4. The sheet stacking apparatus according to claim 2, wherein the belt abutment surface of the belt member is formed with irregularities. 5. The sheet stacking apparatus according to claim 2, wherein a sheet abutting surface of the belt member moves in conjunction with the elevation of the elevation tray. 6. A sheet processing means for processing a sheet on which an image is formed, a sheet stacking means for stacking the sheet processed sheet,
A sheet processing apparatus, comprising: the sheet stacking device according to claim 1 as the sheet stacking unit. 7. An image forming apparatus comprising: an image forming unit for forming an image on a sheet; and the sheet processing unit according to claim 6, for processing the sheet on which the image is formed.