JPS61185472A - Rubber roller - Google Patents

Abstract

PURPOSE:To obtain a rubber roller having frictional coefficient which is less- changable with time and capable of exactly feeding papers by covering a specific rubber blend on a rigid core. CONSTITUTION:A blend rubber 20 consisting of a chloro-blended rubber and natural rubber of a proportion of 80-20/20-80 by weight is convered on a rigid core 1. The rubber roll so formed is much less lowered and deteriorated by softening in terms of frictional coefficient even when used for long periods of time and capable of exactly feeding papers without staining them. The reason for the excellent characteristics of the rubber roll is that a rubber blend used is composed of chloro-blended rubber which e=tends to be gradually hardened when used at temperatures above 30 deg.C for long periods of time and natural rubber which tends to be gradually softened in a proportion of 80-20/20-80 by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rubber roller. More specifically, the present invention relates to a rubber roller used as a sheet conveyance roller or a platen roller.

[Prior Art] A rubber roller conventionally used as a conveyance roller for paper sheets or a platen roller is made by coating a single piece of rubber on a rigid core body, for example, a metal core body. The reason why a single rubber is coated on a rigid core is that it is easy to obtain a rubber elastic body with hardness, wear resistance, heat resistance, chemical resistance, etc. suitable for use in rollers, and the manufacturing cost is also low. It is.

On the other hand, with the development of office automation, reliability requirements for rubber rolls for office automation equipment are increasing. As a rubber roll used as a conveyance roller or a platen roller for paper sheets, it is important to convey the paper sheets accurately and not to contaminate the paper sheets. Furthermore, it is important that the rubber roll does not deteriorate even after long-term use.

Now, as a rubber roll for accurately transporting paper sheets, it is necessary that the coefficient of friction is large and that it does not decrease even after long-term use. However, with conventional rubber rolls coated with a single layer of rubber, the hardness of the rubber increases with long-term use, resulting in a decrease in the friction coefficient of the rubber roll and a deterioration in the accurate conveyance of paper sheets by the rubber roll. . Therefore, in order to reduce the change in the coefficient of friction of rubber over time, it is possible to use low-hardness rubber, but in this case, the adhesive deterioration of the rubber roll will occur, and paper chips mixed in with paper sheets and dust in the air will adhere to it. As a result, the coefficient of friction decreases, resulting in poor conveyance and contamination of paper sheets.

[Problems to be Solved by the Invention] The present invention has been made based on the above points, and its purpose is to eliminate the drawbacks of the prior art, to reduce the change in the coefficient of friction over time, and to reduce the change over time in the coefficient of friction. As a result, it is an object of the present invention to provide a rubber roller that can accurately convey paper sheets.

[Means for Solving the Problems J] The gist of the present invention is to provide a rubber roll comprising a rubber elastic body coated on a rigid core, wherein the rubber elastic body is composed of chloroprene rubber/natural rubber -80 to 20/ 20-80
The rubber roller is characterized by being made of a blended rubber with a weight ratio of .

In the present invention, the rigid core serves as the rotation axis of the roll, and is made of metal, ceramics, hard plastic, or the like.

In addition, in the present invention, a blended rubber of chloroprene rubber and natural rubber is used as the rubber elastic body because the change in friction coefficient over time is extremely small, and as a result, accurate conveyance of paper sheets can be guaranteed for a long period of time. It is. In the present invention, chloroprene rubber/natural rubber-80 to 20/
The reason why the blended rubber has a weight ratio of 20 to 80 is as follows. That is, if the chloroprene rubber content is 80% or more, the blended amount of natural rubber decreases to 20% or less, and as a result, the secular change in the coefficient of friction deteriorates rapidly. Furthermore, if the chloroprene rubber content is less than 20%, the blended amount of natural rubber will be 80%, and as a result, softening and deterioration during use over time will rapidly increase.

[Function] The function of the present invention is that by coating a rigid core body with a blended rubber having a weight ratio of chloroprene rubber/natural rubber -80 to 20/20 to 80, the coefficient of friction can be reduced even after long-term use. Softening deterioration is extremely small, and as a result, paper sheets can be transported accurately without contaminating them.

The reason why the blended rubber of the present invention exhibits such excellent properties is that it gradually hardens when used at a temperature of 30°C or higher for a long time. When natural rubber gradually softens,
This is because they were blended at a weight ratio of 0-20/20-80. In other words, a blended rubber with this weight ratio shows extremely little change in rubber hardness even after long-term use at temperatures above 30°C, which is the internal temperature of office automation equipment, and as a result, there is almost no change in the coefficient of friction over time. A rubber roller can be obtained.

[Example] Next, examples of the rubber roller of the present invention will be described.

Example 1 Weight ratio of chloroprene rubber and natural rubber in rigid core body: 30
A rubber roller was obtained by coating the rubber roller with a blended rubber of /70 and then polishing the surface using a conventional method. Figure 1 shows a perspective view of the rubber roller thus obtained.
1 is a rigid core body, and 20 is a covered blended rubber elastic body.

Example 2 In the same manner as in Example 1, a rubber roller was obtained by coating and polishing a blended rubber of chloroprene rubber and natural rubber in a weight ratio of 50,150.

Example 3 In the same manner as in Example 1, a rubber roller was obtained by coating and polishing a blended rubber of chloroprene rubber and natural rubber in a weight ratio of 70/30.

Comparative Example 1 A rubber roller coated with natural rubber and polished was obtained in the same manner as in Example 1.

Comparative Example 2 In the same manner as in Example 1, a rubber roller was obtained by coating and polishing a blended rubber of chloroprene rubber and natural rubber in a weight ratio of 15/85.

Comparative Example 3 In the same manner as in Example 1, a rubber roller was obtained by coating and polishing a blended rubber of chloroprene rubber and natural rubber in a weight ratio of 85/15.

Comparative Example 4 A rubber roll made of chloroprene rubber was covered and polished in the same manner as in Example 1.

Next, the initial friction coefficient immediately after manufacture and the friction coefficient after thermal deterioration at 100° C. for 72 hours were measured for the thus obtained rubber rollers of Examples and Comparative Examples. The following table shows the results of these measurements.The friction coefficient was measured using the friction coefficient measuring device shown in FIG. In FIG. 2, the rubber roller 21 is rotatably and evenly fixed to the arm 5 above the branch office 2, and the adjustment weight 6 (W>!
The measurement is carried out by placing the rubber roller 21 on the upper surface of the arm 5 and pressing the outer periphery m of the rubber roller 21 against the drum 8 on which the test paper 7 (paper for reading an optical card) is mounted, and then adjusting the motor 5. The friction force μ is the force (F) when the rubber roller 21 slips with the paper 7, which is applied to the load cell 9.
It was calculated by taking a bladder and using the Sha formula.

μ -F/W □ As is clear from the measurement results of the friction coefficient, the friction coefficient of the rubber roller of the present invention hardly changes even after thermal deterioration at 100°C for 72 hours, and as a result, accurate conveyance of snacks is possible. It is.

[Effects of the Invention] The rubber roller of the present invention shows almost no change in the coefficient of friction over time, and as a result, it can accurately convey paper sheets even after long-term use, and is industrially useful. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a rubber roller of the present invention, and FIG. 2 is an explanatory view showing a friction coefficient measuring device for a rubber roller. 1: Rigid core, 2: Branch, 3: Balance weight 4: Arm, 5: Motor, 6: V4 adjustment weight. 7: Test paper, 8 Ni drums, 9: Load cell. 20: Blend rubber elastic body, 21: Rubber roller.

Claims (1)

[Claims] (1) A rubber roll comprising a rubber elastic body coated on a rigid core, characterized in that the rubber elastic body is made of a blended rubber with a weight ratio of chloroprene rubber/natural rubber = 80 to 20/20 to 80. rubber roller.