JPH0485227A - Paper feeder - Google Patents

Abstract

PURPOSE:To prevent multifeeding of sheets by providing a separator having a frictional resisting force larger than the frictional resisting force between sheets in a position a little to the center from the outer periphery of a feed roller and holding the second and following sheets by the separator. CONSTITUTION:When a feed roller 11 is driven to rotate, the top sheet 12 is fed out from stacked sheets 12 in the sheet discharge direction. The fed-out sheet 12 is bent a little inward by a separator 14 in a space with the adjacent feed roller 11, and when a sheet 12 fed out in an overlapping state gets over the separator 14, the lower sheet 12 (second and following) is separated from the first sheet 12 by the frictional resistance with the separator 14, and the first sheet 12 is fed out along the feed roller 11 in the sheet discharge direction. Accordingly, as the separator 14 has a larger frictional resisting force than the frictional resisting force between the sheets, the sheets 12 can be separated so as to prevent multifeeding of sheets 12.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a paper feeding device such as a printer having an automatic paper feeding mechanism.

<Prior Art> An automatic postcard paper feeding mechanism is shown in FIGS. 4 and 5 as a paper feeding device in a conventional printer such as a thermal transfer recording device.

As shown in the figure, a postcard 1 is fed by a feed roller 2 and guided along the outer peripheral surface of the feed roller 2 to a platen 4 by a pinch roller 3. The paper is then printed by the print head on the platen 4, fed out in small increments, and sequentially sent to the paper ejection stocker 6 by the paper ejection roller 5.

When feeding a large number of postcards 1, the overlapped postcards 1 get caught on the separation rib 7 when they pass over the separation rib 7 provided protruding in the paper feed path, and the postcards 1 are stopped. are separated, and sent out one by one.

<Problems to be Solved by the Invention> However, with the conventional separation rib 7, when the paper is thin such as plain paper, the second and third sheets of paper do not catch on the separation rib 7, and the first sheet There is a problem that the paper sticks to the paper and goes over the separation rib 7, resulting in double feeding.

In view of the above, an object of the present invention is to provide a paper feeding device that can prevent double feeding of paper.

<Means for Solving the Problems> As shown in FIG. 1.2, the means for solving the problems according to the present invention includes a plurality of paper feed rollers 11 supported by a rotatable roller shaft IO, and stacked paper sheets. The separating body 14 separates the paper 12 one by one when the paper 12 is sent out by the feed roller 11.
between the feed rollers 11, and between the feed rollers 11.
It is located at a position closer to the center than the outer periphery.

Effects> In the problem solving means described above, when the feed roller 11 is rotationally driven, the upper sheet 12 of the stacked sheets 12 is sent out in the sheet discharge direction.

Then, between the adjacent feed rollers 11, the paper 12 is slightly bent inward by the separator 14, and the paper 12 that is fed overlaps with the paper 12.
When the paper 12 climbs over the separator 14, the lower paper 12 (second and subsequent sheets) becomes the first paper 1 due to the frictional resistance with the separator 14.
2, and the first sheet 12 is sent out along the feed roller 11 in the paper discharge direction.

Therefore, since the separator 14 has a frictional resistance force greater than the frictional resistance force between sheets, it is possible to separate the sheets 12 and prevent double feeding of the sheets 12.

<Embodiment> Hereinafter, an embodiment in which the paper feeding device of the present invention is applied to a thermal transfer recording device will be described based on the drawings.

FIG. 1 is a schematic diagram of a paper feeding device showing an embodiment of the present invention;
Figure 2 is a plan view of the main part, and Figure 3 is the x in Figure 2.
-X sectional view.

As shown in the figure, the paper feeding device of this embodiment includes a plurality of paper feed rollers 11 supported by a rotatable roller shaft lO, and a paper 12 that is pressed against the feed rollers 11 and guided in the paper ejection direction. and a separator 14 that peels off the sheets 12 one by one when the stacked sheets 12 are fed out by the feed roller 11. It has a resistive force and is provided between the feed rollers 11 at a position closer to the center of the feed rollers 11 than the outer periphery thereof.

The feed roller 11 is externally fitted and fixed on a roller shaft 10 at regular intervals, and the roller shaft 10 is connected to a drive device via a drive gear and is driven to rotate clockwise.

Two pinch rollers 13 are arranged along the paper ejection direction so as to circumscribe each feed roller 1, and are rotatably supported on a fixed shaft.

Further, a paper guide plate 15 is disposed on the front side of the pinch roller 13 in the rotational direction of the feed roller 11, and the guide plate 15 is inclined so as to be parallel to the tangent line to the feed roller 11. Paper sheets 12 are stacked on a board 15.

A pressure bonding plate 1 is disposed below the guide plate 15 for supporting the lower end of the paper 12 and for pressing the uppermost paper 12 of the stacked papers 12 against the feed roller 11.
6 is provided, and the crimp plate 6 is urged upward by a compression spring 17.

Furthermore, a friction material 18 is attached to the upper surface of the pressure bonding plate 16 to prevent the paper 12 from slipping.

The separator 14 has a friction material 19 on the surface facing the feed roller 11 of the separation rib 7 used in a conventional paper feeding device.
are attached to the adjacent feed rollers 11.
As shown in FIG. I'm here.

The friction materials 18 and 19 are made of tape-shaped felt or the like, and have a frictional resistance force with the paper 12 that is greater than a frictional resistance force between the paper sheets.

Then, as shown in FIG. 1, the paper 12 rubs against the feed roller 11 at a portion A on the front side of the separator 14, then rubs against each other at the corner 7a of the separator 14, and then again between the feed roller 11 and the separator. They rub against each other in the 8th section that exceeds 14. Further, the lower end of the stacked sheets 12 is connected to the friction material 18 of the pressure bonding plate 16.
Here, the frictional resistance force at each friction part is μr between the feed roller 11 and the paper 12, μb between the separator 14 and the paper 12, and μp1 between the pressure bonding plate 16 and the paper 12. Now, assuming μS, the following relationship holds true in order to feed out the paper 12 one by one.

μr〉μS+μp+μb μb〉μ6 μp〉μS In the paper feeding device having the above relationship, when the feed roller 11 is rotationally driven by the drive device, the stacked sheets 12 are moved to the feed roller by the urging force of the pressure bonding plate 16. 11, the uppermost sheet 12 is sent out in the sheet ejection direction.

At this time, the lower end of the lower paper 12 is in contact with the friction material 18 of the pressure bonding plate 16, and the frictional resistance force μp between the pressure bonding plate 16 and the paper 12 is greater than the frictional resistance force μS between the paper sheets. remain piled up without slipping.

Then, the fed paper I2 passes between the pinch roller 13 and the feed roller 11, and in the portion of the paper 12 that does not come into contact with the feed roller 11, a separating body 14
When the paper 12 is slightly bent inward and the overlapped paper I2 passes over the separator 14,
The lower paper 12 (second and subsequent sheets) is peeled off from the first paper 12 due to frictional resistance with the friction material 19, and the first paper 12 is pulled along the feed roller 11 by the next pinch roller 13. The paper is then sent out in the paper ejection direction.

On the other hand, for the paper 12 caught and stopped by the separator 14, after the first paper 12 is sent out, the frictional resistance between the feed roller 11 and the paper 12 is greater than the frictional resistance between the separator 14 and the paper 12. Therefore, the paper 12 is sent out following the first sheet 12.

Therefore, conventionally, the frictional resistance force of the frictional part of the separation rib was μ
b〈μS (μp〈μS), so there was almost no separation ability for plain paper, but in the present invention, since the separator 14 has a frictional resistance force greater than the frictional resistance force between sheets of paper, μb〉 μS (μp>μS), the second and subsequent sheets of paper 12 are retained by the separator 14, the sheets of paper 12 can be peeled off, and double feeding of the sheets of paper 12 can be prevented.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, in this embodiment, the friction material 19 is attached to the separation rib 7 as the separation body 14, but the separation rib itself may be made of a material with high frictional resistance.

Further, minute irregularities may be formed on the surface of the separation rib to increase the frictional resistance.

The present invention can be applied not only to thermal transfer recording devices but also to devices that feed and read originals, such as copying machines and scanners.

<Effects of the Invention> As is clear from the above description, according to the present invention, a plurality of paper feed rollers supported by a rotatable roller shaft, and a plurality of paper feed rollers supported by a rotatable roller shaft, and stacked paper sheets that are fed out by the feed rollers, a separator that peels off the sheets one by one, the separator has a frictional resistance force greater than the frictional resistance force between the paper sheets, and the separator has a frictional resistance force greater than the frictional resistance force between the paper sheets, and the separating body has entered between the feed rollers and closer to the center than the outer periphery of the feed rollers. Because the sheets are placed in the same position, when the sheets fed out overlapped by the feed roller go over the separator, the second and subsequent sheets are held back by the separator, which prevents double feeding of sheets. It has a positive effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a paper feeding device showing an embodiment of the present invention;
Figure 2 is a plan view of the main part, and Figure 3 is the X in Figure 2.
-X sectional view, FIG. 4 is a schematic diagram of a paper feeding device of a conventional thermal transfer recording apparatus, and FIG. 5 is a plan view of the main part. 10: roller shaft, ll: feed roller, 12: paper,
13: Pinch roller, 14: Separator. Applicant Sharp Corporation

Claims (1)

[Claims] It is equipped with a plurality of paper feed rollers supported by a rotatable roller shaft, and a separator that peels off the stacked paper sheets one by one when the feed rollers feed the stacked paper sheets. A paper feeding device having a frictional resistance force greater than a frictional resistance force and provided at a position between the feed rollers and closer to the center than the outer periphery of the feed rollers.