JPH08634B2 - Rubber member for paper feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber member for a paper feeding device,
More specifically, the present invention relates to a rubber member such as a rubber roller or a double feed preventing rubber pad that smoothly feeds sheets one by one in a sheet feeding device such as a copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art In a sheet feeding device such as a copying machine, a facsimile or a printer, a sheet feeding roller (see FIG. 1) is used to feed a large number of sheets set in a cassette one by one. A member (2) such as a double feed prevention rubber pad or a rubber roller is provided so as to face 1). Note that FIG. 1 illustrates a rubber pad as the double feed preventing rubber member (2).

Conventionally, as the double feed preventing rubber member (2), urethane, a combination of urethane and cork, natural rubber, chloroprene and the like having excellent wear resistance have been used.

[0004]

By using the paper feed roller (1) and the double feed preventing rubber member (2), as shown in FIG.
As shown in Fig. 4, in order to smoothly feed a large number of paper sheets (3) (3) set in a cassette or the like one by one, the friction coefficient between the members is expressed by the following formula 1. Need to be satisfied.

Μ _F > μ _R > μ _p Equation 1

Here, μ _F is a friction coefficient between the paper feed roller (1) and the paper sheets (3), and μ _R is a friction coefficient between the double feed preventing rubber member (2) and the paper sheets (3). , Μ _p are friction coefficients between the paper sheets (3), (3), ...

The above relationship must be maintained even when at least 100,000 sheets have been passed.

Therefore, with the members currently in practical use,
As a result of measuring μ _F and μ _P , μ _P is 0.3 to 0.6 and μ _F is 1.5 to 2.5, so μ _R is 0.7 to 1.2.
Is desirable. Further, in the case of the film for OHP (overhead projector), mu _P is 0.3 to 1.5, mu _F
Is 2.5 to 3.0, so μ _R is preferably 1.7 to 2.4.

By the way, the conventional multi-feed preventing rubber member (2) using urethane, a combination of urethane and cork, natural rubber, chloroprene, etc. has the following problems.

Paper powder generated during the feeding of plain paper adheres to the surface of the rubber member to reduce the friction coefficient, and the above expression 1 cannot be satisfied.

[0012] In conventional rubber member to the friction coefficient mu _R of plain paper, there friction coefficient mu _R of the OHP film is about 2.5 times or more, there is a problem with the paper feed of the OHP film. Moreover, even if the paper can be fed, coated paper or OHP
An unusual noise called "squeaking" is generated when a film for use in the film is sent.

In recent years, a large amount of polynorbornene-based rubber has been used for the paper feed roller (1) used facing each other. This rubber contains 100 to 250 parts by weight of process oil based on 100 parts by weight of polymer. Therefore, when a paper feed mechanism that is in constant contact with the paper feed roller (1) is adopted, deformation due to swelling and an increase in the friction coefficient become problems.

As a result of various studies and studies in view of the above conventional problems, the present inventors have found that rubber, which is excellent in mechanical properties such as abrasion resistance and oil resistance, comes into contact with paper sheets (3) during paper feeding. It was found that an abnormal noise called "squeaking" was generated when the silicone rubber was used, while the silicone rubber, which has relatively poor mechanical properties, hardly generated a squeal. However, since silicone rubber is inferior in abrasion resistance, at least 50,000 sheets or more are usually used in this application.
In some cases, the amount of wear is small even if 150,000 or more sheets are passed,
Since it is necessary that the friction coefficient is stable, it cannot be used alone.

Therefore, it is an object of the present invention to provide a rubber member for a paper feeding device which is excellent in mechanical characteristics and which does not cause abnormal noise during paper feeding.

[0016]

In order to achieve the above-mentioned object, the present invention provides a rubber member for a paper feeding device, which contains a mixture of silicone rubber and oil resistant rubber as a main component.

Further, the present invention is characterized in that the oil resistant rubber is NBR or acrylic rubber.

[0018]

The silicone rubber used in the present invention is
Although it has relatively poor mechanical properties, it is possible to prevent the generation of abnormal noise during sheet feeding. Therefore, if silicone oil is mixed with oil resistant rubber having excellent mechanical properties, the mechanical properties can be significantly improved as compared with the silicone rubber alone, and both mechanical properties and prevention of abnormal noise can be achieved. it can. NBR or acrylic rubber is suitable as the oil resistant rubber. Here, NBR and acrylic rubber were selected as the oil resistant rubber because NBR is a rubber member that is the most resistant to noise among the oil resistant rubbers and has a large degree of freedom in compounding. This is because it is a rubber member having excellent mechanical properties among rubber.

[0019]

Embodiments of the present invention will be described below.

The rubber members A and B containing the silicone rubber alone as the main component and the rubber members of Examples C to I containing the rubber composition obtained in the formulation example shown in the formulation table of Table 1 below as the main components are overlapped. An anti-feed rubber member was formed, and an experiment for measuring their mechanical properties was performed. The results are shown in Table 2 below.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

As described above, according to the present invention, a silicone rubber which is relatively inferior in mechanical properties but hardly produces an abnormal noise at the time of feeding and an oil resistant rubber which is excellent in mechanical properties. By mixing, it is possible to obtain a rubber member for a paper feeding device, which has excellent mechanical properties and does not cause abnormal noise during paper feeding. In addition, when feeding plain paper, the difference between the dynamic friction coefficient and the static friction coefficient is large, so it has excellent suppression performance,
The paper can move smoothly on the surface. Further, in the case of this rubber member, even if the filler is added, the friction coefficient does not change so much with respect to the plain paper, but with respect to the OHP film, the friction coefficient can be reduced according to the addition amount, By utilizing this, it is possible to adjust the friction coefficient of the OHP film suitable for various sheet feeding mechanisms.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a sheet feeding device.

[Explanation of symbols]

 1 Paper feed roller 2 Double feed prevention rubber member 3 Paper sheets

Claims (2)

[Claims] 1. A rubber member for a sheet feeding device, which comprises a mixture of silicone rubber and oil resistant rubber as a main component. 2. The rubber member for a sheet feeding device according to claim 1, wherein the oil resistant rubber is NBR (acrylonitrile-butadiene copolymer rubber) or acrylic rubber.