JPS6256061B2 - - Google Patents

Description

[Detailed description of the invention]

B. Object of the Invention Industrial Field of Application The present invention relates to a rubber member for preventing double feeding of a paper feeding device, and more specifically to a plain paper copying machine (hereinafter abbreviated as PPC), a facsimile machine, a printing machine for a computer, or a printing machine for a computer. The present invention relates to a rubber member for preventing double feeding, such as a rubber plate, a rubber roller, or a rubber belt, which is used together with a paper feed roller or a paper feed belt in a paper feed device such as a bill counting machine. Conventional technology There are two
To prevent more than one piece of paper from being fed to the photosensitive section, printing section, or counting section at the same time while being attracted,
As shown in FIG. 2, a rubber plate 2 or a rubber roller for preventing double feeding is provided opposite to the paper feed roller 1 or the paper feed belt. In such a paper feeding device, the surface friction coefficient (μ
value) is usually about 0.3, so the surface friction coefficient (μ value) between the paper feed roller 1 and the preceding first piece of paper P ₁
is 1.5 or more, and the surface friction coefficient (μ value) between the subsequent second paper piece P ₂ located below the first paper piece P 1 and the rubber plate ₂ for preventing double feeding is 0.6 to 1.2. ,
More preferably, it is adjusted to about 1.0, thereby preventing a double feeding phenomenon between the first piece of paper _P1 and the second piece of paper _P2 . The rubber plate 2 for preventing double feeding is made of a synthetic rubber material such as natural rubber, butadiene rubber, butyl rubber, or ethylene-propylene-diene ternary copolymer rubber.
As the paper pieces P ₁ , P ₂ , etc. are pressed against each other by constant friction, wear resistance is required.
From this point of view, urethane is prized. Furthermore, among the components of the paper feeding device, the paper feeding roller 1 must be able to reliably feed the pieces of paper P ₁ , P _{2 .} . . to subsequent processes such as the photosensitive section and the printing section at a uniform transfer speed. In order to provide the paper feed roller with good surface friction characteristics in response to such requirements, high oil malleable rubber is used as proposed in the invention of Utility Model Application Publication No. 170337/1988, which was previously filed by the applicant of the present invention. We manufacture paper feed rollers from In this case, in response to the high oil malleability of the paper feed roller 1, the rubber plate 2 for preventing double feeding installed opposite to the paper feed roller 1 is made of nitrile-butadiene copolymer rubber in addition to the urethane rubber. , it is necessary to manufacture it from oil-resistant rubber such as fluoro rubber or acrylic rubber. Problems to be Solved by the Invention However, when the rubber plate 2 and the rubber roller for preventing double feeding are manufactured from oil-resistant rubber, paper pieces P ₁ , P ₂ . . .
In particular, when a mirror-finished piece of paper rubs against the double-feed prevention rubber plate 2, an unpleasant creaking sound commonly known as "squeal" is generated. This squeaking phenomenon is thought to be due to the following reasons. In general, when two objects with a high coefficient of friction are pressed together and rubbed against each other, noise is generated. Therefore, in the paper feeding device, if a rubber plate is made of oil-resistant rubber with a high coefficient of friction to prevent double feeding, and pieces of mirror-finished paper with a particularly high coefficient of friction are fed to the paper feeding device, the pieces of paper will stick tightly to the rubber plate. When moving, the two rub against each other, and at this time, it is thought that a frictional sound, or "squeak", is generated. Incidentally, "squeal" does not occur in rubber plates for preventing double feeding made of natural rubber with a low coefficient of friction or synthetic rubber with poor oil resistance, such as BR, IIR, EPDM, etc., but in this case, cannot cope with the high oil malleability of the paper feed roller 1. The main object of the present invention is to improve the oil resistance of the rubber member for preventing double feeding, which is installed opposite to the paper feed roller or paper feed belt and is made of a highly oil malleable rubber member, and to improve the friction with the paper pieces. To provide a rubber member for preventing double feeding of a paper feeding device, which has the ability to prevent unpleasant squeaks and greatly improves the ability to prevent double feeding compared to conventional paper feeding devices. (b) Means for Solving the Constituent Problems of the Invention In view of the above-mentioned objects, the present invention provides a composition containing oil-resistant rubber as a main component containing about 10 to 50% by weight based on the total weight of the composition. The gist of the present invention is a rubber member for preventing double feeding of a paper feeding device, which is made of a mixture of cork particles and is embedded so that at least a part of the cork particles are exposed on the surface. Preferred embodiments Examples of oil-resistant rubber that can be used in the present invention include urethane rubber, nitrile-butadiene copolymer rubber, fluorocarbon rubber, and acrylic rubber. It is desirable that the rubber has the same wear resistance, and from this point of view, urethane rubber is most suitable. The cork particles are present in the composition containing the oil-resistant rubber as a main component, based on the total weight of the composition.
50% by weight, more preferably
It is mixed in a proportion of 10 to 20 weight percent. The rubber member for preventing double feeding, which has been preformed into a plate shape or roller shape by a known molding method, is buffed in a finishing step so that the cork particles are exposed on the surface. If the weight ratio of cork particles exceeds the upper limit of 50% by weight, the surface friction coefficient (μ value) of the rubber member for preventing double feeding will decrease.
The speed decreases, the uniformity of the paper feeding speed is disturbed, and a double feed phenomenon occurs. Incidentally, the surface friction coefficient of cork (μ
value) is approximately 0.3, and the surface friction coefficient (μ value) between pieces of paper
is almost the same as On the other hand, if the weight ratio of cork particles falls below the lower limit of 10% by weight,
“Squeal” occurs and the usability of the paper feeding device is impaired. As mentioned above, this squeaking phenomenon is thought to be caused by the paper adhering to the rubber member slipping at the moment it is released, but if a cork particle surface exists on the surface of the rubber member as described above, the paper and rubber will not stick together. Therefore, it is thought that the "squeal" phenomenon does not occur because the paper separates from the rubber without causing any slippage, and there are many experimental examples. On the other hand, the particle size of the cork particles is desirably adjusted to a range of 10 to 80 mesh, more preferably 20 to 40 mesh, and the hardness of the rubber member for preventing double feeding made by mixing the cork particles is JIS It is desirable that the angle indicated by A be maintained within the range of 50 to 80 degrees. By adjusting the particle size of the cork particles and the hardness of the finally obtained rubber member as described above, the surface friction coefficient (μ value) between the paper piece P and the rubber member 2 for preventing double feeding can be adjusted to “squeal”. ” and can be maintained within a range of 0.6 to 1.2, which is suitable for preventing double feeding. Example A rubber plate for preventing double feeding was molded from the following materials whose compounding ratios are expressed in percent by weight.

[Table] After a rubber plate was preformed using the above-mentioned rubber composition using a known molding device, the surface of the rubber plate was backed up to expose a portion of the cork particles 3 on the same plane as the rubber plate surface. The surface structure of the finally obtained rubber plate 2 for preventing double feeding is shown in FIG. 1 as a partially enlarged view. The rubber plate 2 for preventing double feeding thus obtained was attached to the paper feeding device shown in FIG. 2, and a paper feeding test was carried out under standard conditions. When the double-feed prevention rubber plate described in this example was used, no "squeal" phenomenon occurred at all, and a stable paper feeding state without paper jams could be maintained. . Comparative example The amount of cork particles in the above example was changed to 140
A rubber plate was manufactured according to the same process as in the above example except that parts by weight (50.4%) and 15 parts by weight (9.8%) were changed. The obtained rubber plate was attached to a paper feeding device, and a paper feeding test was performed under the same conditions as above. As a result, in the former case, a double feeding phenomenon of paper pieces occurred, and in the latter case, a "squeak" phenomenon similar to the known rubber plate made of urethane rubber alone occurred. C. Effects of the Invention As can be understood from the above explanation, approximately 10 to 50 weight percent, more preferably 10 to 20 weight percent, of cork particles are mixed into a composition containing oil-resistant rubber as a main component, and the cork particles are By exposing a part of the cork to the surface, the presence of cork particles reduces the coefficient of friction without compromising wear resistance.
The occurrence of "squeal" phenomenon in the rubber member for preventing double feeding is suppressed, and two or more pieces of paper are fed out at the same time. The inconvenience of clogging has been completely eliminated. Thus, the present invention can exhibit a remarkable effect on improving the operational stability of the paper feeding device.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged view of the surface structure of a rubber member for preventing double feeding according to the present invention, and FIG. 2 is a schematic side view illustrating a paper feeding device. P... piece of paper, 1... paper feed roller, 2... rubber plate for preventing double feeding, 3... cork particles.

Claims (1)

[Scope of Claims] 1. A composition containing oil-resistant rubber as a main component, in which cork particles are mixed in an amount of about 10 to 50 percent by weight based on the total weight of the composition, and at least one of the cork particles is mixed with the composition. 1. A rubber member for preventing double feeding of a paper feeding device, characterized in that the rubber member is buried so that a portion thereof is exposed on the surface. 2. The rubber member for preventing double feeding of a paper feeding device according to claim 1, wherein the oil-resistant rubber is urethane. 3. The rubber member for preventing double feeding of a paper feeding device according to claim 1, wherein the cork particles have a particle size of 10 to 80 mesh. 4. The rubber member for preventing double feeding of a paper feeding device according to claim 1 or 2, wherein the composition has a hardness of JIS-A 50 to 80 degrees.