JPH0459527A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a fluctuation in the load after completion of sheet feeding operation and to perform high-precise sheet feeding a simple constitution by setting the position of a stopper member, by which a sheet on a placing plate is prevented from making contact with the notch part of a feed roller, so that a distance between the rear end of a sheet before the feed of a sheet and the stopper member is decreased to a value lower than the moving distance of a sheet by sheet feed operation. CONSTITUTION:Provided a distance between the rear end of a sheet before the feed of a sheet and a stopper member 4 is L1 and a moving distance of a sheet by sheet feed operation is L2, the position of the stopper member 4 is positioned so as to establish a formula of L1< L2. Therefore, in a completion state of sheet feed operation, a rear end E of a fed sheet is positioned closer to the feed roller 11 side than the stopper member 4. Since, in this state, a load on sheet conveyance is not exerted on a fed sheet, a fluctuation in a load is not produced during following sheet feed and smooth sheet feed is practicable. After completion of sheet feed operation, operation to move a loading carriage 22 for a printing head 21 in the direction of the width of a sheet and sheet feed operation to rotate a platen 20 by a given sheet feed amount by a drive mechanism are repeated to effect printing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device for use in copying machines, printers, etc., which separates and feeds sheets of paper cut into predetermined dimensions one by one.

[Prior Art] A conventional paper feeding device, as typified by Japanese Unexamined Patent Publication No. 61-282237, has a configuration shown in a side sectional view of FIG. 5. P represents paper, 101 is a half-moon-shaped paper feed roller that feeds the paper, 102 is a paper feed shaft, and 103 is a separation pad. When the paper feed roller 101 rotates, the corner of section A contacts the paper P and separates the paper P. 104 is separation pad 1
This is a spring that elastically supports 03. 105 is a separation idler roller, which is located on the paper feed shaft 102, is slightly smaller than the radius of the paper feed roller 101, and is located on the paper feed shaft 102.
When 01 is not in contact with the separation pads 10 and 3, it is in contact with the separation pad 103 and rotates freely. 110 is a lower guide, 111 is an upper guide, 112 is a pair of conveying rollers, 106
107 is a middle plate that pushes up the paper P, and 106 is a middle plate 106.
This is a spring that pushes up the middle plate. Paper feed shaft 10
2 incorporates a one-turn clutch (not shown).

The positional relationship among the paper feed roller 101, separation pad 103, separation idler roller 105, and paper P is normally as follows. The paper feed roller 101 is stopped with its flat part facing down, and the separation idler roller 105 and separation pad 10
3 is in elastic contact. In addition, the separation idler roller 1
05 is a spring 107 pushing up the middle plate from below through the middle plate 106.
It is also in contact with the paper P which is being lifted up by. From this state, when a paper feed command is issued and the paper feed roller 101 rotates, the paper feed roller 101 comes into contact with the paper P. Furthermore, when the paper feed roller 101 rotates, it pushes down the separation pad 103 and feeds the paper P to the separation pad 103, but only the uppermost paper is fed due to the difference in frictional force between the separation pad 103 and the paper feed roller 101. Since the paper feed roller 101 has a built-in one-turn clutch, it rotates once during paper feeding, conveys the paper a certain distance, and then stops. Since the conveyance distance by one rotation of the paper feed roller 101 is set longer than the distance between the conveyance roller 112 and the paper feed roller 101, the paper P reaches the conveyance roller 112 by one rotation of the paper feed roller 101. Thereafter, the paper is transported by rotation of the transport roller 112.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the paper is transported by the conveyance roller 112.
In the conveyed state, the conveyed paper is sandwiched between the paper feed idler roller 105 and the paper on the middle plate 106 that is pushed up by the middle plate push-up spring 107.

Therefore, the paper feed idler roller 1 is attached to the conveyance roller 112.
A load is applied, which is the sum of the friction load due to the rotation of 05 and the friction load obtained by multiplying the friction coefficient between the sheets by the spring force of the middle plate push-up spring 107. These two frictional loads are caused by the paper being conveyed and the trailing edge of the paper being applied to the paper feed idler roller 105.
Since it becomes zero the moment it leaves, a large load fluctuation occurs at that moment. Such large load fluctuations are undesirable because they appear as poor paper feeding pitches. As a countermeasure for the poor paper feed pitch, it is possible to increase the paper feed force of the transport roller 112 to prevent load fluctuations from causing poor paper feed pitch, but this is possible only by increasing the driving force of the paper feed drive system. However, this method has the problem of increasing the size and cost of the paper feed motor. The present invention is intended to solve these problems.The purpose of the present invention is to eliminate the load on the drive system after the paper feeding operation is completed using a simple mechanism, thereby eliminating paper feeding pitch defects. This is where the paper feeding device is provided.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the paper feeding device of the present invention includes a paper feeding roller having a cross section where a part of the circumference is cut out, and a paper feeding device that stacks paper and moves in the direction of the paper feeding roller. In a paper feed device for a printer that has a paper stacking plate that is constantly energized and a friction separation plate that separates sheets of paper stacked on the paper stacking plate one by one, the missing circular portion of the paper feeding roller a stopper member disposed so as to separate the paper a predetermined distance from the paper feed roller so that the uppermost paper stacked on the paper stacking plate does not contact the paper feed roller in a facing state; However, when the paper reaches the printing start position of the printer and the paper feeding operation is completed, the paper does not come into contact with the fed paper and the paper next to the fed paper (the highest paper on the paper stacking plate) ) The position of the stopper member was set at such a position that it came into contact with.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIGS. 2 and 3 are cross-sectional views showing the paper feeding operation in the embodiment of the present invention. FIG. 4 is a perspective view showing an embodiment of the present invention.

In FIG. 1, l is a paper cassette body that stores paper. The paper cassette main body 1 is supported so as to be swingable about a fulcrum 2a. A paper stacking plate 2 is attached to the paper cassette main body 1, and paper 3 is stacked on it. The paper stacking plate 2 is pushed up by a biasing device 6 such as a compression coil spring toward a paper feed roller 11 that feeds the paper 3 into the printer body. Furthermore, one sheet of paper 3 is placed in front of the sheet of paper 3.
A friction separation plate 7 that separates the vapor cassette body 1 is fixed to the vapor cassette body 1. The paper feed roller 11 does not rotate except when performing a paper feeding operation, and is stopped with the surface without a circumference located on the side facing the paper 3 as shown in the figure. .

When a paper feed command is issued, a paper feed roller drive mechanism (not shown) rotates the square shaft 10 to rotate the paper feed roller 11 fixed to the square shaft 10, and when the paper feed roller 11 rotates once, It operates as a one-turn clutch that stops again at the position shown in the figure.

That is, when the paper feed roller 11 is stopped and the surface without a circumferential portion is located on the side facing the paper 3 as shown in FIG. 1, the paper 3 and the paper stacking plate 2 are It is supported by the biasing device 6 in a state in which it is in contact with the stopper member 4 as shown in the figure. The stopper member 4 has holes 1 provided on both sides of the vapor cassette body 1 as shown in FIG.
It is constituted by a shaft that is fitted in a and is long in the width direction of the paper.

Reference numeral 20 denotes a platen on which printing is performed by wrapping the paper 3 around it, and a carriage 22 is disposed on the platen 20 to reciprocate in the printing width direction.

A printing pad 21 is mounted on the carriage 22. A paper guide 23 and a paper feed roller 24 are disposed between the paper feed roller 11 and the print head 21 to convey the paper sent out by the paper feed roller 11 to a printing position.

When a paper feed command is issued to the printer configured as described above, the square shaft 10 is rotated by a paper feed roller driving device (not shown), and the paper feed roller 11 is rotated clockwise, as shown in FIG. Begin to.

The paper feed roller 11 pushes down the paper 3 and pushes the paper 3 toward the friction separation plate 7 by frictional force to separate the topmost sheet of the paper 3. The separated paper is conveyed to a paper feeding position via a paper guide 23 and a paper feed roller 24.

FIG. 3 shows a state in which the paper is conveyed to the paper feeding position. As shown in the figure, if the distance between the trailing edge of the paper before being fed and the stopper member 4 is Ll, and the distance L2 is the distance that the paper has moved due to the paper feeding operation, then the distance between the stopper member 4 and the trailing edge of the paper before being fed is Ll, and the distance L2 is the distance that the paper has moved due to the paper feeding operation. Since the position is set, the trailing edge E of the fed paper is located closer to the paper feed roller 11 than the stopper member 4 when the paper feeding operation is completed. In this state, since there is no load on paper transport for the fed paper, no load fluctuation occurs during subsequent paper feeding, and smooth paper feeding is possible.

After the paper feeding operation is completed, there is a carriage operation in which the carriage 22 on which the printing pad 21 is mounted is moved in the paper width direction, and a paper feeding operation in which the platen 20 is rotated by a predetermined paper feeding amount by a paper feeding drive mechanism (not shown). Printing is performed by repeating these steps.

[Effects of the Invention] As described above, according to the present invention, the position of the stopper member that prevents the paper stacked on the paper stacking plate from coming into contact with the missing circular portion of the paper feed roller is adjusted by adjusting the position of the stopper member when the paper is fed. If Ll is the distance between the trailing edge of the previous paper and the stopper member, and L2 is the distance traveled by the paper during the paper feeding operation, by setting Ll<L2, the load will be reduced after the paper feeding operation is completed. This has the effect of realizing highly accurate paper feeding with a simple configuration without causing fluctuations.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention. Figures 2 and 3
The figure is a sectional view showing the paper feeding operation of the present invention. FIG. 4 is a perspective view showing an embodiment of the present invention. FIG. 5 is a sectional view showing a conventional paper feeding device. 2...Paper stacking plate, 3...Paper, 4...Stopper member, 7...Friction separation plate, 11...Paper feed roller. that's all

Claims (1)

[Claims] A paper feed roller having a cross section where a part of the circumference is cut out, a paper stacking plate loaded with paper and constantly biased in the direction of the paper feeding roller, and a sheet of paper stacked on the paper stacking plate one by one. In a printer paper feed device having a friction separation plate that separates,
With the missing circular portion of the paper feed roller facing the paper,
a stopper member disposed to separate the paper by a predetermined distance from the paper feed roller so that the uppermost paper stacked on the paper stacking plate does not contact the paper feed roller; When the printing start position of the printer is reached and the paper feeding operation is completed, the printer does not touch the fed paper but contacts the paper next to the fed paper (the uppermost paper on the paper stacking plate). A paper feeding device characterized in that the stopper member is set at a position.