JPH04201933A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent double feed of recording sheets of paper by sending back with vibration while feeding is made with feed roller for recording sheets taken out of an accommodation chamber, and thereby transporting only one recording sheet certainly. CONSTITUTION:A feed roller 3 is furnished to pinch a recording sheet of paper 1 taken out of an accommodation chamber and give the sheet a transport force in the direction of feeding, and oppositely to this feed roller 3 a vibrating means 4 is arranged, which prevents double feed of recording sheets 1, 2 by giving the sheet 2 a transport force in the direction of sending back through the vibratory action. Thereby such a transport force in the direction of sending back is given to an eventually fed sheet 2 as following the intended one, and double feed of recording sheets is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device used in a printer or the like.

[Prior Art] Conventionally, printers use a paper feed system in which recording paper is stored in a stack in a paper cassette one by one using a picking roller, is fed to a feed roller, and then conveyed to a printing position by the feed roller. equipment is used. However, when stacked recording paper is cut, the edges of the paper may be compressed and the paper may stick to each other, or the paper may be stuck together due to static electricity. In such cases, it is not uncommon for the picking roller to pick out not only one recording paper but two or more recording sheets. Therefore, in order to prevent such double feeding of recording paper, the paper feed cassette is equipped with a separation claw that comes into contact with the corner of the recording paper, and when taking out the recording paper, the separation claw curls the topmost recording paper and separates it into two sheets. There is a known method in which a retard roller is provided that separates the recording paper from the first recording paper or comes into elastic contact with the feed roller, and the second and subsequent recording sheets are sent back by the retard roller.

[Problems to be Solved] With the device provided with a separation claw, it is difficult to separate the combined recording sheets, and it is difficult to reliably prevent double feeding of the recording sheets.

Further, in the case where a retard roller is used, the shaft of the retard roller is driven via a torque limiter or a vine using a friction member. The torque of the torque limiter is smaller than the driving force of the feed roller and the frictional force between the feed roller and the recording paper (and should be set larger than the frictional force between the recording paper and the recording paper.For this reason, the configuration is complicated and adjustment is difficult. There have been problems in that it is difficult to manage the coefficient of friction, and a mechanism for rotating the retard roller is required, making the configuration complicated and increasing costs.

゛Therefore, an object of the present invention is to provide a paper feeding device that has a simple configuration and can reliably prevent double feeding of recording paper.

[Means for Solving the Problems] In order to achieve the above object, the paper feeding device of the present invention pinches the recording paper taken out from the recording paper storage chamber and applies a conveyance force in the feeding direction to the recording paper. A feed roller and a vibrating means that prevent double feeding of the recording paper by applying a conveyance force in the sending and returning direction to the recording paper by vibration are disposed opposite to each other.

The above-mentioned vibration means may be constituted by a vibration wave generating means using a piezoelectric element, or may be constituted by a return piece driven by vibration.

[Function] When a second sheet of recording paper follows, the vibrating means provided opposite the feed roller applies a conveying force in the forwarding direction to this recording sheet, thereby preventing double feeding of recording sheets. be done.

[Example 1] The present invention is intended to prevent double feeding of recording paper by providing a vibration means and using the principle of vibration transport to apply a conveying force in the feeding and returning direction to the recording paper. Showing a first example,
In this example, a piezoelectric element is used as the vibration means 4 to generate traveling waves.

That is, when two recording sheets 1.2, for example, are taken out from the recording sheet storage chamber by a picking roller (not shown),
This recording paper is fed between the feed roller 3 and the vibrating means 4. As a vibration means, an elastic body 6 is fixed to the case 5 of the printer main body via a support member 6a, and a plurality of piezoelectric ceramics 7 are arranged on the bottom surface of the elastic body 6, as shown in FIG. As shown in FIG.

AC voltages with a temporal phase shift of 90 degrees are applied to each piezoelectric ceramic 7. For example, when 10O9ωt is applied to sinωt, the vibration of the elastic body 6 becomes a traveling wave that moves in the direction of arrow C with time. Note that λ shown in the second diagram is the wavelength of the flexural vibration of this traveling wave. When a moving object is placed on the elastic body 6 where this traveling wave is excited, the moving object is moved in the opposite direction to the direction in which the traveling wave travels.

Therefore, in the first diagram, since the second recording paper 2 is in contact with the elastic body 6, the uppermost recording paper 1 is conveyed in the direction indicated by the arrow, which is the feeding direction, by the counterclockwise rotation of the feed roller 3. At this time, the second recording paper 2 is sent in the direction of arrow B, which is the return direction opposite to the direction of arrow C, which is the direction in which the traveling wave advances. This is recording paper 1
This is the sending-back direction in the opposite direction to the direction of arrow A, which is the feeding direction.

FIGS. 3A and 3B show a second embodiment, in which the vibrating means 14 uses a return piece. That is,
The paper feed cassette 1 is
When, for example, two recording sheets 11 and 12 are taken out from the recording paper 0, these recording sheets are fed between the feed roller 13 and the vibrating means 14. As a vibration means, a vibrator 16 is installed upright on a case 15 of the printer body, and a return piece 17 is fixed to the tip of the vibrator. A magnetic material 16 is included in the vibrator 16.
A is fixed. The tip of the iron core 18 constituting the electromagnetic device for driving the vibrator faces the magnetic body 16a at a predetermined distance, and is capable of being magnetically coupled. A driving coil 19 is wound around the iron core 18. By applying a sinusoidal current to the drive coil 19, the vibrator 16 is driven to vibrate. Also, from case 15, paper guide 2
0 is provided upright, and the return position of the vibrator 16 is regulated by a stopper 21)a protruding from this paper guide.

To explain the operation of conveying the recording paper, when a current is supplied to one drive coil, the iron core 18 is excited and the vibrator 1
The magnetic body 16a of No. 6 is attracted, and the vibrator 16 is deflected to the right as shown in Fig. (B). At this time, the moving speed in the direction of the arrow d given to the return piece 17 is sufficiently fast, so there is no slippage between the recording paper 12 and the return piece 17, and the recording paper 12 does not follow and move in the direction of the arrow d. . When the suction force from the iron core 18 is released and the vibrator 16 returns to the original position shown in FIG.
returns at a slower rate than before. During this return, the recording paper 11 comes into contact with the feed roller 13 due to the reaction of the return piece 17, so the counterclockwise rotation of the feed roller 13 applies a conveying force to the recording paper 11 in the direction of feeding it to the printing position. , transported in the direction of arrow A. At this time, the recording paper 12 also comes into contact with the recording paper 11 due to the reaction of the return piece 17 and tries to follow its conveyance, but the foot roller 1
The conveyance force does not reach the recording paper 12 due to the gap f provided between the return piece 3 and the return piece 17.

At the second tongue, the recording paper 12 is pushed back in the return direction (in the direction of arrow B) by the frictional force between it and the return piece 17. In this way, the recording paper 11 is sent out and the recording paper 12 is sent back at the same time, so double feeding of the recording papers is prevented.

[Effects] The paper feeding device of the present invention having the above configuration uses a feed roller to feed the recording paper taken out from the recording paper storage chamber and then sends it back by vibration, so that it reliably feeds only one recording paper. It is possible to prevent double feeding of recording paper by conveying the paper. This makes it possible to improve the reliability of printing.

Further, since the number of parts is small, the configuration is simple, and there is no need to manage the coefficient of friction, it is possible to reduce costs.

[Brief explanation of the drawing]

Fig. 1 is a front view of essential parts showing one embodiment of the present invention, Fig. 2 is a principle diagram of the vibration wave generating means, and Figs. 3 (A) and (B) show another embodiment of the present invention together with its operation. FIG. 10...Recording paper storage chamber, 1,=,11.12...Recording paper, 3,]3...Feed roller, 4.14...Vibration means, 7...Piezoelectric element, 17. ...Returning piece, A...Feeding direction, B...Feeding back direction. that's all

Claims (3)

[Claims] (1) Hold the recording paper taken out from the recording paper storage chamber,
A feed roller that applies a conveying force in the sending direction to the recording paper, and a vibration means that applies a conveying force in the sending back direction to the recording paper by vibration to prevent double feeding of the recording paper are arranged oppositely. A paper feeding device characterized by: (2) The paper feeding device according to claim 1, wherein the vibrating means is a vibrating wave generating means using a piezoelectric element. (3) The paper feeding device according to claim 1, wherein the vibrating means is a return piece driven by vibration.