JP2787625B2 - Media stain prevention mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for preventing a medium from being stained in a sheet feeding apparatus using a belt for separating sheets.

[0002] This type of sheet feeding device is incorporated in a sheet feeding section of a printer device, a scanner device or the like, and plays a role of separating and supplying sheets one by one. When this paper feeding device is used in an optical character reading device (OCR device) which is one of the scanner devices, it is important to prevent the paper from being stained.

[0003]

2. Description of the Related Art FIG. 4 shows an outline of the structure of a conventional sheet feeding apparatus using a belt. FIG. 4A is a front view of the sheet feeding device, and FIG.
4B is a side view of the same, and FIG. 4C is a cross-sectional view of the belt. In the drawing, reference numeral 1 denotes a feeding roller, 2 denotes a belt, and 3 denotes a roller with a torque limiter. The belt 2 is stretched around pulleys 4, 5, and 6, and is driven by a pulley 4 connected to a drive system (not shown) to travel in the direction of arrow A. The belt 2 is urged by a spring (not shown) in the direction of arrow B about the axis of the pulley 4 as a fulcrum. Specifically, each of the pulleys 4, 5, and 6 is supported by a support plate (not shown), and the support plate is urged in the direction of arrow B by a spring. The cross-sectional shape of the belt 2 is as shown in FIG.

[0004] The roller 3 has a belt 2 between pulleys 4 and 5.
Are arranged opposite to each other. The roller 3 has a built-in torque limiter. The belt 2 is on the driving side and the rollers are on the driven side.

At the time of paper feeding, a paper (medium) 100 is fed by a feeding roller 1. Dispensed paper 10
Numeral 0 enters the conveyance path 7 and is conveyed by being pressed against the roller 3 by the belt 2 receiving the urging force of the above-mentioned spring (not shown). Roller 3 holds the fed paper 1
It rotates when it is a sheet, but when two or more sheets are fed, it stops by the action of the torque limiter to prevent the double hood of the sheet.

[0006]

By the way, in the OCR apparatus in which the paper feeding device is incorporated, the powder of the pencil of the character written on the paper is transferred to the belt 2, and this is again transferred to the paper, which causes erroneous reading and rejection. Etc. The dirt on the paper that occurs in this way is particularly severe in this part because the force is not uniformly applied to the belt and concentrates on both side edges as shown by a double arrow line in FIG. 4C. This stain becomes remarkable when the pulley around which the belt is wound has runout.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mechanism for preventing a medium from being stained in a sheet feeding device.

[0008]

In order to achieve the above object, according to the present invention, a belt wound around a plurality of pulleys and pressed against a medium fed to a conveying path to separate and convey the medium is provided. Wherein at least all of the plurality of pulleys of the plurality of pulleys are provided with relief so as not to press against both side ends of the belt. I do.

[0009] Further, it is wound around a plurality of pulleys, and
Separation and conveyance of the medium by pressing against the medium to be fed from above
In the sheet feeder provided with a single belt, a relief is provided on both sides of the belt on the side of the conveyance path.

[0010]

As described above, since the relief is provided at the portion corresponding to both ends of the belt of the pulley or at both ends of the belt on the side of the conveyance path, the pressure distribution when the belt contacts the medium is equalized. As a result, a local pressure increase that has caused the contamination is prevented. Therefore, it is possible to reduce the contamination of the medium which has conventionally been a problem.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIGS. 1 and 2 show a first embodiment.

FIG. 1 is a side view showing a main part of the sheet feeding apparatus of the present embodiment. In FIG. 1, reference numeral 11 denotes a driving pulley, reference numerals 12 and 13 denote driven pulleys, and reference numeral 14 denotes a bridge between these pulleys 11, 12, and 13. Belt. In addition to these, the paper feeding device
(A) and (B) are provided with a feeding roller and a roller with a torque limiter.

Each pulley is provided with a concave relief 15 at a position corresponding to both ends of the belt 14, as shown in FIG. 2, which is a sectional view taken along the line II in FIG. The belt 14 has the same rectangular cross-sectional shape as that of the related art.

Thus, in this example, the pulley 1
5, the pressure distribution when the belt 14 contacts the medium fed in the direction of arrow C is equalized, and Local pressure rise, which has been the cause, is prevented.
Therefore, it is possible to reduce the contamination of the medium which has conventionally been a problem. In addition, the relief 15 is the pulley 1 on the conveyance path side.
It may be provided only in the first and the second 12.

FIG. 3 shows a second embodiment.

In the case of this example, the pulley is kept as it is,
Escapes 22 such as C chamfers are provided at both ends of the belt 21 on the side of the conveyance path (the lower side in the figure). The paper feeding device is provided with a feeding roller (not shown), each pulley, and a roller with a torque limiter, in addition to the belt.

In the present embodiment, as in the previous embodiment, a local pressure increase when the belt 21 comes into contact with the fed medium can be prevented, the pressure distribution can be equalized, and the medium is less contaminated. .

[0019]

As described above, according to the present invention, by providing a clearance at a portion corresponding to both ends of the belt of the pulley or at both ends of the belt on the side of the conveyance path, the belt can be supplied to the medium to be fed. The pressure distribution can be equalized by preventing a local pressure rise when the pieces come into contact with each other, and the stain on the medium can be reduced. Therefore, when the present invention is applied to an OCR paper feeder, it is possible to prevent erroneous reading and reading failure due to medium contamination. Further, the present invention is effective when gripping a medium with a large pressure.

[Brief description of the drawings]

FIG. 1 is a side view showing a main part of a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II in FIG.

FIG. 3 is a sectional view of a belt according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating the structure of a conventional sheet feeding device.
4A is a front view of the sheet feeding device, FIG. 4B is a side view thereof, and FIG. 4C is a cross-sectional view of the belt.

[Explanation of symbols]

 11,12,13 Pulley 14,21 Belt 15,22 Escape

Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B65H 1/00-3/68

Claims (2)

(57) [Claims] A paper feeder provided with a belt (14) wound around a plurality of pulleys (11, 12, 13) and pressed against a medium fed to a transport path to separate and transport the medium. In (15) , at least all the pulleys (11, 12) of the plurality of pulleys (11, 12, 13) on the conveying path side are slid so as not to press against both side ends of the belt (14).
A medium contamination prevention mechanism, characterized by comprising: 2. A belt (14) wound around a plurality of pulleys (11, 12, 13) and pressed against a medium fed to a conveyance path from above to separate and convey the medium. In the paper feeder provided, the belt (14) has an escape (2
(2) A medium contamination preventing mechanism provided with (2).