JPH06100179A - Sheet stacking apparatus and image forming apparatus using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] Sheet 15 due to static electricity generated on sheet 15
It is possible to prevent double feeding of sheets 15 and defective feeding such as jam caused by the electrostatic close contact. [Structure] In a sheet stacking unit that stacks sheets 15,
A charge eliminating needle 20 for eliminating static electricity generated on the sheet 15 is provided to improve the separability of the sheet 15.

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 for stacking and storing a large number of sheets, and more particularly to a method for solving a factor of difficulty in separating and feeding sheets such as static electricity generated on the sheets.

[0002]

2. Description of the Related Art Conventionally, a sheet stacking device used in an image forming apparatus such as a copying machine will be described with reference to FIGS. FIG. 10 is a top view of the sheet stacking apparatus, and FIG.
10 is a sectional view taken along line BB in FIG. The sheet stacking device has a frame body 11 (storage member), and a rear end regulation plate 16 for regulating the end portion of the sheet in the frame body 11.
And the side regulation plate 17 is provided. Also, the frame 1
An intermediate plate 13 is provided at the tip of the first plate 1, and the intermediate plate 13 is biased upward (upward in FIG. 10) by a compression spring 14. Furthermore, separation claws 12 are provided at corners of the frame body 11 in the sheet conveying direction (on the left side in FIG. 10) to suppress the leading edge corners of the sheet 15.

When the paper feeding operation is started in the above structure,
The sheet feeding roller 18 frictionally engages with the uppermost sheet 15 to feed the sheet. At this time, the sheet is separated by passing over the separation claw 12.

[0004]

However, in the above-described sheet stacking apparatus, static electricity is generated in the sheets due to rubbing or peeling between the stacked sheets 1, and therefore strong static electricity is generated between the sheets 15. Adhesion occurs. In such a case, it is difficult to separate and feed the sheets 15 one by one,
It was a cause of double feed and jam. In particular, such a charging phenomenon has a characteristic that it tends to occur when the humidity is low.

Therefore, an object of the present invention is to provide a sheet stacking apparatus and an image forming apparatus using the sheet stacking apparatus, in which even if static electricity is generated on the sheets, troubles such as double feeding of sheets and jamming do not occur.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a storage member (11) for stacking and storing a large number of sheets, and a rear end regulating means for regulating the rear end position of the sheets. (25) and a sheet stacking device in which sheets are fed one by one from the storage member (11), the trailing edge regulating member (25) separates the sheets by bending the sheets. Therefore, the lower part of the rear end of the stacked and stored sheets is lifted and supported.

For example, a cross section of the abutting portion of the trailing edge regulating member (25) with which the trailing edge of the sheet abuts has a wedge shape, and the sheets are sequentially displaced from the uppermost sheet in the sheet conveying direction, and the sheet is moved. It will be handled.

Further, the accommodating member (11) is provided with a vibration generating means (27) for vibrating and separating a plurality of sheets electrostatically adhered by static electricity.

Further, the accommodating member (11) is provided with a discharging means (20) for discharging the static electricity of the electrostatically adhered sheet to improve the separability of the sheet.

Further, the storage member is provided with a pressing means (30) for pressing the sheets from the uppermost sheet surface with a predetermined pressing force so as to prevent the sheets from being double-fed.

The pressing means (3) for pressing the sheet
The pressing surface of 0) has a curved surface with a large radius of curvature so that the pressing surface is always pressed even if the height of the uppermost sheet changes due to the change in the number of stacked sheets.

The pressing means (30) has a pressing portion (31) made of a rotatable body.

Further, the pressing means (30) has an acute-angled pressing portion (31).

The image forming apparatus (2) has an image forming section for forming original image information on a sheet, and a sheet stacking apparatus according to any one of claims 1 to 5. To do.

[0015]

According to the above construction, the trailing edge regulating means (25) for regulating the trailing edge of the stacked sheets is provided, and the trailing edge regulating means (25) lifts the trailing edge of the sheet or is loaded. The sheets are separated by sequentially shifting the positions of the sheets, and the static electricity generated in the sheets is discharged by the discharging unit (20) to improve the separability of the sheets. Further, the storage member (11) accommodating and stacking the sheets is provided with the vibration generating means (27), so that the closely attached sheets are vibrated, and the vibration improves the separability of the sheets.

Further, in order to prevent double feeding of stacked sheets and jamming, the uppermost sheet is pressed by means (3).
Press 0).

The reference numerals in parentheses described above are for the purpose of contrasting with the drawings, but do not limit the structure of the present invention.

[0018]

【Example】

<First Embodiment> A first embodiment of the present invention will be described below with reference to the drawings. Since the basic configuration of the sheet stacking apparatus in the first embodiment is substantially the same as that of the conventional technique, the same reference numerals are given and only the different points will be described.

As shown in FIG. 1, the sheet stacking apparatus 1 is provided with a trailing edge regulating plate 25 (trailing edge regulating means), and the trailing edge regulating plate 25 has a trailing edge portion of the sheet 15 placed thereon. Has a slanted surface, and the surface that regulates the rear end of the sheet is formed at a right angle to the slanted surface. This makes seat 1
5 Since the front end portion is lifted by the middle plate 13 and the rear end portion is lifted by the rear end regulating plate 25, the seat 15 becomes like an air fishing due to the waist strength of the seat 15. Therefore,
A minute space is generated between the sheets 15, and it becomes possible to prevent feeding failure such as double feeding of the sheets 15 due to electrostatic adhesion of the sheets 15 due to static electricity.

According to the experiment conducted by the inventor, when 10,000 sheets were copied using the A4 size sheet 15, 10 sheets were double-fed when the rear end regulating plate 16 of the conventional structure was used. When the trailing edge regulating plate 25 of this Example 1 was used, only two sheets were double fed.

As a method of making the effect of the first embodiment more conspicuous, if the material of the rear end regulating member 25 is made of a conductive material such as metal and the rear end regulating plate 25 is installed, It is possible to eliminate the static electricity generated on the sheet 15, and it is possible to prevent feeding failure such as double feeding caused by the static electricity. <Second Embodiment> A second embodiment of the present invention will be described with reference to the drawings.
Since the basic structure of the sheet stacking device is substantially the same as that of the first embodiment, the same reference numerals are given and only different points will be described.

FIG. 2 shows a vibration generating means 28 for providing vibration to the sheet stacking apparatus 1.
Is composed of a weight 26 and a motor 27. Then, the motor 27 is rotated during the feeding operation to vibrate the sheet stacking apparatus 1, and the vibrating the sheets 15 which are in close contact with each other by this vibration can improve the separability between the sheets 15. .

Of course, the vibration generating means is not limited to the one having the above construction. <Third Embodiment> A third embodiment of the present invention will be described with reference to the drawings.
Since the basic structure of the sheet stacking device is substantially the same as that of the first embodiment, the same reference numerals are given and only different points will be described.

FIG. 3 shows a top view of the sheet stacking apparatus 1,
Further, FIG. 4 shows a sectional view of a portion AA in FIG. The sheet stacking device 1 has a charge eliminating needle 20 (charge eliminating means), a ground plate 21, and a rear end regulating plate 29. The static elimination needle 2
0 is provided at the leading end of the sheet stacking apparatus 1 to make an electrical contact with a charged sheet, and the ground plate 21.
This makes it possible to take out static electricity to the outside. The cross section of the abutting portion of the trailing edge regulating plate 29 with which the sheet 15 abuts has a wedge shape, and when a large number of sheets 15 are placed on the sheet stacking apparatus 1, the effect of separating the sheets 15 is generated. . Therefore, when the sheet 15 is placed, the sheet 15 is separated, and the static elimination needle 20 eliminates static electricity, so that it is possible to prevent double feeding of the sheet 15.

As a means for preventing electrostatic contact due to static electricity generated by the sheets 15, for example, repulsive force may be generated between the sheets 15 by applying static electricity from the static elimination needle 20 in addition to the method described above. <Fourth Embodiment> A fourth embodiment of the present invention will be described with reference to the drawings.
Since the basic structure of the sheet stacking device is substantially the same as that of the first embodiment, the same reference numerals are given and only different points will be described.

5 to 8 are views for explaining the fourth embodiment of the present invention, and FIG. 5 is a perspective view of the sheet stacking apparatus 1.
The sheet stacking apparatus 1 has a pressing unit 30, and the pressing unit includes a pressing unit 31 as shown in FIG. The pressing surface of the pressing portion 31 is formed of a curved surface having a large radius of curvature so that the pressing surface is always pressed even when the amount of stacked sheets changes. At the time of feeding, the pressing means 30 comes into contact with the uppermost sheet 15 with a predetermined pressure, so that the lower sheets (the second and lower sheets) are pressed down, so only the uppermost sheet 15 is fed. It

If the pressing force of the pressing means 30 against the sheet 15 is larger than the force of the sheet feeding roller 18 to feed the sheet 15, the uppermost sheet 15 is not fed, so that the pressing means 30 pushes the sheet. The force for pressing 15 must be smaller than the feeding force by the feeding roller 18. Further, even if the frictional force between the pressing means 30 and the uppermost sheet 15 exceeds the frictional force between the sheet feeding roller 18 and the sheet 15, the sheet 15 is not fed.

In addition to the shape of the pressing portion 31 of the pressing means 30, the roller type shown in FIG. 7 and the steeple shape shown in FIG. 8 can achieve the same effect. <Fifth Embodiment> A fifth embodiment of the present invention will be described with reference to the drawings.
Since the basic structure of the sheet stacking device is substantially the same as that of the fourth embodiment, the same reference numerals are given and only different points will be described.

Sheet stacking apparatus 1 having pressing means 30
9 is mounted on the image forming apparatus 2 as shown in FIG. 9, and the sheet 15 stacked on the sheet stacking apparatus 1 is fed by a sheet feeding roller 18, passes through a conveying guide 32, and is conveyed by a conveying roller 33 and a registration roller 34. After that, the toner image formed on the photoconductor 35 is transferred to the sheet 15. After that, the sheet 15 having the image formed thereon is discharged by the conveyance belt 37 through the fixing device 38, and the image forming operation is completed. By using the sheet feeding means 1 as described above, since the fed sheets 15 are not double-fed, it is possible to reduce conveyance defects such as jams even during conveyance.

[0030]

As described above, according to the present invention, the trailing edge regulating means for regulating the trailing edge of the stacked sheets is provided,
This restricting means lifts the rear end of the seat, or
By sequentially shifting the positions of the stacked sheets, the sheets are separated, and by removing the static electricity generated on the sheets by the static eliminator, the separability of the sheets can be improved. Further, by providing a vibration generating means in the storage member that stacks and stores the sheets, the closely contacted sheets are vibrated,
This vibration improves the separability of the sheets, and by pressing the uppermost sheet by the pressing means, it is possible to prevent the stacked sheets from being fed, jammed, etc., improving the reliability of the device. did.

[Brief description of drawings]

FIG. 1 is a side view of a sheet stacking device applied to a first embodiment of the present invention.

FIG. 2 is a side view of the sheet stacking device applied to the second embodiment of the present invention.

FIG. 3 is a top view of a sheet stacking device applied to a third embodiment of the present invention.

FIG. 4 is a side view of a sheet stacking device applied to a third embodiment of the present invention.

FIG. 5 is a perspective view of a sheet stacking device applied to a fourth embodiment of the present invention.

FIG. 6 is a side view of a pressing unit applied to Example 4 of the present invention.

FIG. 7 is a side view of another pressing means applied to the fourth embodiment of the present invention.

FIG. 8 is a side view of another pressing means applied to the fourth embodiment of the present invention.

FIG. 9 is a side view of an image forming apparatus applied to Example 5 of the invention.

FIG. 10 is a top view of the sheet stacking unit applied to the description of the conventional technique.

FIG. 11 is a side view of the sheet stacking unit applied to the description of the conventional technique.

[Explanation of symbols]

 2 image forming apparatus 11 frame (storage member) 20 static elimination needle (static elimination means) 25 rear end regulating plate (rear end regulating means) 26 weight (vibration generating means) 27 motor (vibration generating means) 30 pressing means 31 pressing part

Claims (9)

[Claims] 1. A sheet stack including a storage member for stacking and storing a large number of sheets, and a rear end regulating means for regulating a rear end position of the sheets, wherein the sheets are fed one by one from the storage member. In the apparatus, the trailing edge regulating member lifts and supports the lower portion of the trailing edge of the stacked and stored sheets so as to separate the sheets by bending the sheets, and the sheet stacking apparatus. 2. The rear end regulating member with which the rear end of the sheet abuts has a wedge-shaped cross-section, and the sheets are separated by sequentially shifting the position from the uppermost sheet in the sheet conveying direction. The sheet stacking device according to claim 1. 3. The sheet stacking apparatus according to claim 1, wherein the storage member includes a vibration generating unit that vibrates and separates a plurality of sheets that are electrostatically adhered by static electricity. 4. The sheet stacking apparatus according to claim 1, wherein the storage member is provided with a discharging unit that discharges static electricity from the electrostatically adhered sheets to improve the separability of the sheets. 5. The sheet stacking apparatus according to claim 1, wherein the storage member has a pressing unit that presses the sheets from the uppermost sheet surface with a predetermined pressing force to prevent double feeding of the sheets. 6. The pressing surface of the pressing means for pressing a sheet has a large radius of curvature so as to always press the surface even if the height of the uppermost sheet changes due to a change in the number of stacked sheets. The sheet stacking device according to claim 5, which has a curved surface. 7. The sheet stacking apparatus according to claim 5, wherein the pressing unit has a pressing unit formed of a rotatable body. 8. The sheet stacking apparatus according to claim 5, wherein the pressing unit has an acute-angled pressing portion. 9. An image forming apparatus, comprising: an image forming unit for forming an image of document information on a sheet; and the sheet stacking device according to claim 1.