JPH0624587A - Paper feeding device - Google Patents

Abstract

PURPOSE:To make it possible to feed only the uppermost one sheet of the loaded papers securely to a pressure holding conveying roller by composing the circular arc of a feed roller with a larger diameter circular arc which has a shorter arc length contacting to the upper surface of the loaded papers at the first part of one rotation, and a smaller diameter circular arc contacting to the latter part of the rotation. CONSTITUTION:When a feed roller 5 is rotated one round from the condition shown in the figure by a shaft 6, a larger diameter circular arc 5a with a shorter arc length is contacted to the upper surface of the loaded papers P at first at a strong pressure and at a fast speed proportional to the diameter, and the uppermost paper is removed from a separation claw 4. Then, a smaller diameter circular arc 5b is contacted to the upper surface of the loaded papers P at a weak pressure and at a slow speed proportional to the diameter, and the uppermost paper removed from the separation claw 4 now movable easily is fed in a pair of pressure holding rollers 7. Since the delivered paper is fed further to the left by the pair of conveying rollers 7, the loaded papers P can be delivered sheet by sheet securely, by rotating again the feed roller 5 one round at least after the rear end of the paper passes the position of the separation claw 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for use in a copying machine, a printer or the like, which sequentially feeds one stacked sheet from the uppermost sheet.

[0002]

2. Description of the Related Art As a paper feeding device as described above, a stack of papers on a mounting plate is locked by a separating claw against the rising of the mounting plate by a spring bias, and each time the half-moon-shaped feed roller makes one rotation. A sheet feeding device is often used in which an arcuate portion is brought into contact with the upper surface of the stacked sheets and the uppermost sheet is detached from the separation claws and fed to a pair of pressure-conveying rollers. The arc portion had a single diameter.

[0003]

In the above-described paper feeding device, there is a problem that a plurality of sheets of paper are sometimes fed into the pair of pressure-feeding conveyance rollers in an overlapping manner by one rotation of the feeding roller. The present invention has been made to solve the problem, and an object of the present invention is to provide a sheet feeding device in which only one uppermost sheet of stacked sheets is fed to a pair of pressure-feeding rollers by one rotation of the feeding roller. To do.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a stack of paper on a mounting plate is locked by a separating claw to prevent the mounting plate from being lifted by a spring force, and an arc is generated each time the half-moon-shaped feed roller rotates once. In the paper feeding device for bringing the uppermost paper from the separation claw to feed the paper to the pair of pressure-conveying rollers, the arc portion of the sending roller is the first portion of the one rotation of the stacked paper. There is provided a sheet feeding device characterized by comprising a large-diameter circular arc portion having a short arc length which comes into contact with the upper surface, and a small-diameter circular arc portion which comes into contact with the upper surface of the stacked sheets thereafter. This configuration achieves the above object.

[0005]

That is, the feeding roller of the paper feeding device of the present invention is
In one rotation, the large-diameter circular arc portion having a short arc length first comes into contact with the upper surface of the stacked paper at a relatively high pressure and a high speed to remove the uppermost paper from the separation claw, and then the small-diameter circular arc portion of the stacked paper. The uppermost paper, which comes into contact with the upper surface at a relatively low pressure and a slow speed and is easily separated from the separation claws, is fed to the pair of sandwiching pressure conveying rollers, so that a pair of sandwiched papers are piled up. It is prevented from being sent to the pressure conveyance roller.

[0006]

The present invention will be described below with reference to the illustrated examples.

FIG. 1 is a sectional view showing an example of a sheet feeding device of the present invention, and FIG. 2 is a partial perspective view showing an example of a feeding roller.

In FIG. 1, 1 is a paper feed cassette, 2 is a loading plate which is biased by a spring 3 so that the left end side rises, P is a stacked sheet on the loading plate 2, and 4 is a front end of the stacked sheet P. Separation claws 5 provided on the paper feed cassette 1 so as to engage with the upper surfaces of both sides and suppress the rise due to the urging of the spring 3 are appropriately distributed by the shaft 6 in the center position in the width direction of the stacked paper P and in the width direction. Is a half-moon-shaped delivery roller that is supported so as to hit the corresponding position and is rotated once in the arrow direction from the illustrated state to the illustrated state. Reference numeral 7 is a pair of pressure-feeding rollers that rotate in the arrow direction.

When the delivery roller 5 is rotated once by the shaft 6 from the illustrated state, the large-diameter arc portion 5a having a short arc length.
First comes into contact with the upper surface of the stacked paper P with a strong pressure proportional to the diameter and at a high speed to remove the uppermost paper from the separation claw 4, and then the small-diameter arc portion 5b is weakly proportional to the upper surface of the stacked paper P. The uppermost sheet of paper which comes into contact with the pressure at a slow speed and comes off the separation claw 4 is fed to the pair of pressure-feeding conveyance rollers 7. Then, since the pair of transport rollers 7 continuously feeds the fed paper to the left, by at least rotating the feed roller 5 once after the trailing edge of the paper has passed the position of the separation claw 4, It is possible to reliably send out one stacked sheet P.

The delivery roller 5 shown in FIG. 2 is provided with a groove 5c in the generatrix direction on the small-diameter circular arc portion 5b so as to increase the propulsive force applied to the paper. The joint arm 5d is formed so as to extend parallel to the axis 6. The hook portion at the tip of this elastic engagement arm 5d falls into a groove provided on the shaft 6 to fix the position of the delivery roller 5.

The delivery roller 5 as described above can be obtained as a molded product of resin or the like, but the invention is not limited to this, and the large-diameter circular arc portion 5a and the small-diameter circular arc portion 5b are made of paper such as rubber. It is preferably made of a high friction material. The large-diameter circular arc portion 5a and the small-diameter circular arc portion 5b of the delivery roller 5 have, for example, a radius of the large-diameter circular arc portion 5a of about 20 mm,
By reducing the radius of the small-diameter circular arc portion 5b by about 10 to 20% and making the arc length of the large-diameter circular arc portion 5a about several mm, the elasticity of the spring 3 is also related, but the above-mentioned effect can be sufficiently obtained. You can However, it goes without saying that the present invention is not limited to the delivery roller having such a size.

[0012]

According to the paper feeding apparatus of the present invention, it is possible to feed the sheets one by one from the uppermost portion of the stacked sheets, and it is possible to obtain a remarkable effect that a plurality of sheets are not fed in an overlapping manner. To be

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a sheet feeding device of the present invention.

FIG. 2 is a partial perspective view showing an example of a delivery roller.

[Explanation of symbols]

 1 Paper Feed Cassette 2 Loading Plate 3 Spring 4 Separation Claw 5 Sending Roller 5a Large-diameter Arc Part 5b Small-diameter Arc Part 7 Clamping Conveyor Roller

Claims (1)

[Claims] 1. A stacking paper on the mounting plate is locked by a separating claw to ascend the rising of the mounting plate by a spring bias, and a half-moon shaped feeding roller is provided.
In a paper feeding device for bringing the arc portion into contact with the upper surface of the stacked sheets and removing the uppermost paper from the separation claw and feeding it to the pair of clamping conveying rollers every time the paper is rotated, the arc portion of the sending roller makes A sheet feeding device comprising a large-diameter circular arc portion having a short circular arc length that first contacts the upper surface of the stacked paper and a small-diameter circular arc portion that subsequently contacts the upper surface of the stacked paper.