JPH09150979A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a jamming and a double feeding by converting the inclination of a separating pad according to the number of feeding papers. SOLUTION: When the nipping condition of a paper feeding roller 12 and a separating pad 14 is 'NO PAPER', or nipping only one sheet of paper, the friction force operated from the paper feeding roller 12 to the separating pad 14 is large, the separating pad 14 exercises a fluctuation to the rotating direction side of the paper feeding roller 12 against the spring force of a spring 28 to control the fluctuation of the separating pad 14, and the inclination of the separating pad 14 is made smaller. When papers more than two sheets are going to be fed, the friction force given to the separating pad 14 from the paper feeding roller 12 is made smaller, and the spring force of the spring 28 to control the fluctuation of the separating pad 14 is made larger than its friction force. Consequently, the separating pad 14 carries out the fluctuation in the direction reverse to the rotating direction of the paper feeding roller 12, and the inclination of the separating pad 14 is made larger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder, and more particularly to an automatic paper feeder for feeding a plurality of sheets stacked on a sheet stand such as a PPC or printer by separating them one by one with a separating pad. Regarding

[0002]

2. Description of the Related Art In a conventional paper feeding device of this type, a separation pad is pressed against a paper feeding roller so that a sheet has a constant plunge angle with respect to the separation pad. When the first sheet of paper is rushed in, the paper is supplied by the difference between the frictional force between the paper feed roller and the paper and the frictional force between the separation pad and the paper, and two or more sheets are rushed in at the same time. If there is, the sheets are sequentially separated by the difference between the frictional force between the paper feed roller and the sheets and the frictional force between the sheets.

[0003]

In a conventional sheet feeding device using a separation pad, in order to prevent a jam and a double-fed sheet feeding in a contradictory manner, the material (friction coefficient) of the separation pad, There is a drawback that it is very difficult to set the inclination angle of the separation pad (paper entry angle) and the spring pressure of the knockup plate.

Therefore, a main object of the present invention is to provide a paper feeding device that can more easily prevent jams during paper feeding and double feeding.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a paper table on which a plurality of sheets of paper can be stacked, a paper feed roller provided at an end of the paper table, and an outer peripheral surface of the paper feed roller are provided. In a paper feeding device including a separation pad that suppresses a paper roller and is swingably held with respect to the paper transport direction,
The sheet feeding device is characterized in that inclination changing means for changing the inclination angle of the separation pad according to the number of sheets between the separation pad and the sheet feeding roller is provided.

[0006]

When there is only one sheet of paper between the paper feed roller and the separation pad, the separation pad swings in the conveying direction due to the frictional force of the paper feed roller given through the paper, and the inclination angle of the separation pad is increased. Get smaller. When there are two or more sheets of paper between the paper feed roller and the separation pand, the separation pad moves in the conveyance direction so that the frictional force between the paper and the spring force of the spring controlling the rocking motion are in balance. And swings in the opposite direction to increase the inclination angle of the separation pad.

In other words, the spring for controlling the swinging motion of the separation pad uses the difference between the frictional force acting on the separation pad from the paper feed roller and the spring force of the spring, and the separation pad balances the two. The rocking operation is performed before and after in the transport direction. If there is no paper in the nip between the paper feed roller and the separation pad, the frictional force that acts on the separation pad becomes the frictional force that directly acts on the separation pad from the paper feed roller, which is against the spring force of the spring. As a result, the separation pad oscillates in the direction of rotation of the paper feed roller, so the inclination angle of the separation pad becomes smaller. When one sheet of paper is fed with the inclination angle being small as described above, the leading edge of the paper is less likely to hit the separation pad, which makes it easier for the paper to pass, and the paper feed jam is less likely to occur.

Under the condition that only one sheet is fed,
The inclination angle of the separation pad is set by a spring force that is kept small due to the frictional force between the sheet and the separation pad.
When two or more sheets of paper are to be fed, the nip condition between the paper feed roller and the separation pad causes a frictional force between the paper and the frictional force applied from the paper feed roller to the separation pad becomes small. Therefore, the spring force of the spring that controls the swinging action becomes larger than the frictional force, and the separation pad swings in the direction opposite to the rotation direction of the sheet feeding roller, and the inclination angle of the separation pad increases. When the angled skin of the separation pad becomes large, the leading edge of the second and subsequent sheets of paper easily hit the separation pad, and the effect of preventing double feed is exhibited.

[0009]

As described above, according to the present invention, when one sheet is fed, the separation pad has a small inclination (paper entry angle), jamming is less likely to occur, and when two or more sheets enter, the separation pad is used. Since the inclination angle (paper entry angle) is large, it is possible to prevent double feeding of paper, and it is possible to prevent jamming and double feeding with an extremely simple configuration.

Other objects and features of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a paper feeding device 10 of this embodiment.
Includes a paper feed roller 12 and a separation pad 14. In FIG. 1, the nip condition between the paper feed roller 12 and the separation pad 14 is “no paper” or “only one sheet”, and the separation pad 14 Shows a state in which the paper feed roller 12 is swung to the full rotation side and the inclination angle is reduced.

A paper feed tray 18 on which a plurality of papers 16 can be stacked is provided on the upstream side of the paper feed roller 12, and the papers 16 on the paper feed tray 18 are supplied to the paper feed roller 12. The separation pad 14 has a flat surface along the peripheral side surface of the paper feed roller 12, and carries out paper feeding of the paper 16. The separation pad 14 is held by a holder 20.
Has a fulcrum on which the separation pad 14 can swing. The holder 20 is further held by the paper passing block 22, and the protrusion 24 provided on the paper passing block 22 abuts on one side surface of the holder 20 to regulate the range of the above-described swinging motion of the separation pad 14. .

A spring 26 for pressing the separation pad 14 against the paper feed roller 12 is provided in the paper passage block 22 on the back side of the separation pad 14. The spring force of the spring 26 acts on the separation pad 14 from the back surface of the separation pad 14,
The separation pad 14 is pressed against the paper feed roller 12. A spring 28 is provided on the frame 30 on the rear side of the separation pad 14 so that the spring force acts in a direction orthogonal to the direction in which the spring force of the spring 26 acts.
8 applies a spring force to the other side surface of the holder 20, and the holder 2
0 is pressed to the above-mentioned protrusion 24 side. That is, the spring 28 controls the swinging motion of the separation pad 14.

Next, the operation will be described. FIG. 1 shows the case where the nip condition between the paper feed roller 12 and the separation pad 14 is "no paper" or only one sheet of paper is nipped. The frictional force that acts on the separation pad 14 from the paper roller 12 is large, and contrary to the spring force of the spring 28 that controls the swing motion of the separation pad 14, the direction of rotation of the paper feed roller 12 (indicated by the arrow in FIG. 1) side. Then, the separation pad 14 oscillates, and the inclination angle θ1 of the separation pad 14 becomes smaller as shown in FIG. This inclination angle θ
When one sheet is fed with 1 being small, the leading edge of the sheet is less likely to hit the separation pad 14, the sheet is more likely to pass, and a paper feed jam is less likely to occur.

FIG. 2 shows a case where two or more sheets are about to be fed. In this case, the nip condition between the sheet feed roller 12 and the separation pad 14 becomes a friction force between the sheets and the sheet is fed. Since the frictional force applied from the paper roller 12 to the separation pad 14 becomes smaller, the spring force of the spring 28 that controls the swinging motion of the separation pad 14 becomes larger than the frictional force. Therefore, the separation pad 14 swings in the direction opposite to the rotation direction of the paper feed roller 12, and the separation pad 14
The inclination angle θ2 becomes large as shown in FIG. When the inclination angle θ2 of the separation pad 14 becomes large, the leading edges of the second and subsequent sheets of paper that have entered are likely to hit the separation pad 14. Therefore, in this case, it is possible to effectively prevent the double feeding of the sheets.

According to this embodiment, the inclination angle of FIG. 1, that is, the plunge angle θ1 of one sheet and the inclination angle of FIG. 2, that is, the plunge angle θ2 of two or more sheets, are set to θ1 <θ2. It is easy to set the paper feed conditions such as the material of the pad 14 (coefficient of friction), the inclination angle of the separation pad 14 (paper entry angle), and the spring pressure of the knock-up plate. It is possible to obtain the effect of prevention and prevention of double-feeding.

In the above embodiment, the spring 24
Coil springs that utilize elastic force as spring force are used as and 28. However, a coil spring that uses a contracting force as the spring force may be used, or a leaf spring may be used.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view showing a sheet feeding device according to an embodiment of the present invention, showing a state in which a separation pad is swung to the full rotation side of a sheet feeding roller and an inclination angle is reduced.

FIG. 2 is a main cross-sectional view showing a state where a separation pad has a large inclination angle in this embodiment.

[Explanation of symbols]

 10 ... Paper feeding device 12 ... Paper feeding roller 14 ... Separation pad 16 ... Paper 20 ... Holder 22 ... Paper passing block 24 ... Spring 28 ... Spring

Claims (2)

[Claims] 1. A paper table on which a plurality of sheets can be stacked, a paper feed roller provided at an end of the paper table, and an outer peripheral surface of the paper feed roller for suppressing the paper feed roller and the paper. And a separation pad held so as to be swingable with respect to the conveyance direction of the separation pad, the inclination angle of the separation pad is changed according to the number of sheets between the separation pad and the paper feed roller. A paper feeding device, characterized in that a tilt angle changing means is provided. 2. The tilt angle changing means includes a spring for controlling the swinging operation of the separation pad with respect to the conveyance direction, and when the number of sheets between the paper feed roller and the separation pad is one, the inclination angle changing means includes the spring. When the separation pad swings toward the conveyance direction and the inclination angle of the separation pad becomes small, and there are two or more sheets between the paper feed roller and the separation pad, the spring causes the inclination of the separation pad. The paper feeding device according to claim 1, wherein the angle is large.