JPH08108591A - Rubber roller - Google Patents

Abstract

PURPOSE: To obtain a rubber roller which maintains a good paper transportation property for a long period of time by specifying the average of measured values at more than one position on the circumferential surface of the roller of the areas occupied by the sea part and the land part which forms a crimp pattern of the circumferential surface of the roller. CONSTITUTION: On the circumferential surface of a rubber roller, a crimp pattern is formed by a land part 1 which is formed along the surface and a sea part 2 which is recessed from the land part 1. The average of measured values at more than one position on the circumferential surface of the roller of the occupancy ratio R (%) of the land part 1 which is obtained from an formula is 30-80%. Where, X indicates the number of small squares of the land part 1 in which no sea part 2 is contained which are obtained by a process in which a photograph of 20 enlargement ratio of an area of a square of about 6mm side in the circumferential surface of the roller is taken, and an area of a square of 100mm side in the photograph is divided into 400 small squares; Y is the number of the small squares in which both land part 1 and sea part 2 exist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber roller used for feeding paper in, for example, a laser beam printer, an electrostatic copying machine, a facsimile, and an automatic cash dispenser (ATM).

[0002]

2. Description of the Related Art The peripheral surface of a rubber roller used for feeding paper has a large coefficient of friction with the paper and is ground by a grinding process or the like in order to improve the transportability of the paper. The surface is roughened so that the 10-point average roughness is about 30 μm. However, there has been a problem that the peripheral surface of the rubber roller is worn and smoothed during repeated contact with the paper, the coefficient of friction is lowered, and poor conveyance of the paper occurs.

Particularly in the case of recording paper with a large amount of ash, a large amount of paper dust generated lowers the friction coefficient of the rubber roller,
The above problems occurred in a short period of time. Therefore, it has been proposed to form a grain pattern having a 10-point average roughness of 20 to 30 μm on the peripheral surface of the rubber roller (Japanese Patent Laid-Open No. 5-2210).
59). Such a rubber roller is manufactured by vulcanizing and molding the rubber composition using a mold having a mold surface corresponding to the peripheral surface of the rubber roller and having a texture pattern.

As described above, the rubber roller having a large surface roughness takes a longer time to be smoothed due to abrasion, as compared with the rubber roller having a small surface roughness, so that the occurrence of paper conveyance failure can be suppressed. It was predicted that the life of the rubber roller could be improved. However, according to the study by the inventors, it has been found that the rubber roller having the texture pattern may not always have good paper transportability.

The 10-point average roughness referred to herein is obtained as follows. That is, first, a range of a reference length of 0.8 mm is set from the sectional curve of the rubber roller, and within this range, the height of the peak portion protruding from the average line corresponding to the peripheral surface of the rubber roller from the average line is set. Along with the measurement, the depth of the valley portion recessed from the average line from the average line is measured. For the measurement, a roughness meter described later is used.

Next, in the case of a mountain portion, five mountain portions from the highest height to the fifth height are selected from the above measured values, and the average value of the heights is obtained. On the other hand, in the case of valleys, five valleys from the deepest one to the fifth deepest are selected, and the average value of the depths is calculated. Then, a value obtained by subtracting the average value of the heights of the peaks and the average value of the depths of the valleys is the 10-point average roughness.

An object of the present invention is to provide a rubber roller which has excellent paper transportability and can maintain the good paper transportability for a long period of time.

[0008]

In order to solve the above-mentioned problems, the inventors of the present invention have examined the texture pattern of the rubber roller disclosed in the above publication, and as shown in FIG. It was found that there is a case in which the friction coefficient is insufficient and the transportability of the paper is deteriorated because of the smooth continuous shape and the small catching of the paper.

Therefore, as a result of various studies on the embossed pattern to be applied to the peripheral surface of the rubber roller, the inventors have found that, for example, as shown in FIGS. 1 (a) and 1 (b), the land surface along the peripheral surface of the roller. It has been found that when a grain pattern in which the portion 1 and the sea portion 2 recessed from the land portion 1 are randomly distributed is used, the coefficient of friction can be improved and the transportability of paper can be improved. However, even with the embossed pattern, the friction coefficient may be insufficient depending on the balance between the land portion 1 and the sea portion 2, and sufficient paper transportability may not be obtained. Therefore, the present inventors have completed the present invention as a result of further studies on the balance between the land portion and the sea portion, which can secure good paper transportability.

That is, the rubber roller of the present invention has a textured pattern formed on the peripheral surface of a rubber roller, which is composed of a land portion along the peripheral surface and a sea portion recessed from the land portion. formula:

[0011]

[Equation 2]

(Where X is a magnified photograph of 20 times a square area having a side of about 6 mm on the roller peripheral surface, and a square area having a side of 100 mm is divided into 400 small squares. When the partition, the number of small squares that do not include the sea and are all land, and Y represents the number of small squares in which both land and sea are mixed.) The average value of the measurement results of R (%) at a plurality of points on the roller circumferential surface is 30 to 80%.

In the rubber roller of the present invention, the land portion and the sea portion forming the grain pattern are properly balanced on the roller peripheral surface, so that the friction coefficient is high and the paper can be reliably conveyed. Further, since the surface texture of the embossed pattern is larger than that of the ground surface or the like, it is possible to maintain the above friction coefficient for a long period of time and secure good paper transportability.

The present invention will be described below. In the present invention, the occupancy rate R of the land portion obtained by the above calculation formula
(%), The average value of the measurement results at multiple points is 30 to 80
The reason why it is limited within the range of% is to secure good paper transportability as described above. That is, if the average value is less than 30%, the proportion of the sea area is too large,
On the contrary, when the average value exceeds 80%, the ratio of the land portion is too large, and in any case, the peripheral surface of the roller is close to a smooth state without the grain pattern, and the friction coefficient is And the paper transportability deteriorates. In contrast,
If the average value is within the range of 30 to 80%, the land portion and the sea portion forming the grain pattern are appropriately balanced on the roller peripheral surface, so that the friction coefficient is high and the paper is reliably transported. It becomes possible.

From the viewpoint of paper transportability, the above average value is particularly preferably 40 to 70% within the above range,
More preferably, it is 45 to 65%. Further, in order to make the paper transportability uniform in one rubber roller, it is preferable that the variation in the measured value of the land area occupancy R (%) at a plurality of points is as small as possible.

In the above calculation formula, the small squares counted in the number X means, for example, a small square S1 surrounded by a dashed line in FIG. The land area 1 is shown. In addition, the small squares counted in the number Y are small squares S in the above figure.
A small square S2 drawn adjacent to 1 indicates that the land portion 1 and the sea portion 2 are mixed in the area. In this case, the ratio of land area 1 and sea area 2 is not particularly limited,
If the land portion 1 and the sea portion 2 coexist even a little, the count is made to Y, but the land portion 1 is not included like the small square S3, and all the sea portions 2 are not counted.

In the rubber roller of the present invention, the surface roughness of the roller peripheral surface approximately corresponds to the dimension of the step between the land portion 1 and the sea portion 2. The range of the surface roughness is not particularly limited in the present invention, but in order to maintain good paper transportability for a long period of time as described above, the surface roughness is 20 μm expressed as a 10-point average roughness. It is preferably not less than 30 μm, more preferably not less than 30 μm.

In the case of the conventional embossed pattern shown in FIG. 3, when the 10-point average roughness exceeds 30 μm, the height of the wave 9 becomes too high as disclosed in column 0011 of the prior application. For example, there is a problem that the paper is apt to be irregularly deformed due to the pressure contact force to the paper, and as a result, the paper feeding is defective. On the other hand, in the case of the rubber roller of the present invention, even if a pressure contact force is applied to the paper, as shown by the chain double-dashed line in FIG. Since a large deformation that affects the
It is also possible to set the surface roughness to 30 μm or more in terms of 10-point average roughness, in which case good paper transportability can be maintained for a longer period of time than when the surface roughness is 30 μm or less. There is an effect.

When the land area occupancy rate R (%) obtained by the above formula is a constant value, as is clear from the results of Examples described later, the greater the surface roughness, namely, The larger the level difference between the land portion 1 and the sea portion 2, the better the paper transportability. This is land area 1 and sea area 2
It is considered that when the difference in level with is large, the land portion 1 is easily deformed in the lateral direction as shown in FIG. 2, the biting of the roller peripheral surface to the paper is improved, and the friction coefficient is increased. .

Therefore, considering only the friction coefficient, the larger the surface roughness of the roller peripheral surface is, the more preferable it is. However, the occupation ratio R (%) of the land portion, that is, the surface area is too large compared with the land portion size. If the roughness is too large, the land portion 1 may be broken on the way due to the above deformation. Therefore, it is desirable to set the optimum surface roughness in consideration of the mechanical and physical strengths of the rubber forming the roller, the land area occupancy rate R (%), that is, the size of the land area. .

The rubber roller of the present invention is manufactured by vulcanizing and molding the rubber composition using a mold whose peripheral surface corresponds to the surface of the mold, and which has a pattern corresponding to the texture pattern. To be done. The rubber composition is produced by melting the base rubber and, if necessary, various additives and kneading.

As the base rubber, for example, natural rubber (N
R), isoprene rubber (IR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), chloroprene rubber (CR), fluorine rubber (FKM), butyl rubber (IIR), ethylene-propylene copolymer Polymerized rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM), silicone rubber, epichlorohydrin rubber (CO, ECO), polysulfide rubber (T), urethane rubber (U) and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the additives include reinforcing agents or fillers such as carbon black, silica, clay and talc, various softening agents, plasticizers, processing aids, vulcanizing agents, vulcanization accelerators, vulcanization retarders, Antiaging agents etc. are mentioned.

[0024]

EXAMPLES The rubber roller of the present invention will be described below based on Examples and Comparative Examples. Examples 1 to 5 and Comparative Examples 1 and 2 The following components were blended and kneaded to produce rubber compositions. (Components) (parts by weight) -EPDM 100 (trade name of Esprene, manufactured by Sumitomo Chemical Co., Ltd.)-Filler 20-Paraffin oil 10-Sulfur 0.5-Vulcanization accelerator 5.5 Next, the circumference of the rubber roller Using a mold whose surface corresponding to the surface is processed by etching to correspond to the texture pattern composed of the land portion and the sea portion,
A rubber roller (diameter 24 mm × width 28 mm) was manufactured by vulcanization and molding under the conditions of 70 ° C. and 20 minutes.

Occupancy rate R (%) of the land portion in the grain pattern formed on the peripheral surface of the rubber roller of each of the examples and comparative examples.
, The average value at 5 points on the roller surface [5 point average R
(%)], And 10-point average roughness (μm) are shown in Table 1.
It is shown in FIG. The five-point average R (%) was measured by cutting out a square sample of about 6 mm on each side from five points on the circumferential surface of the manufactured rubber roller, and taking a 20 times magnified photograph of the sample. The square area is divided into 400 small squares, and the land area occupancy rate R (%) calculated by the above formula from the number of small squares counted according to the above criteria
Was calculated by averaging.

The 10-point average roughness was obtained by using the roughness meter (SURFCOM) manufactured by Tokyo Seimitsu Co., Ltd. and the surface condition data of the rubber rollers of each of the examples and comparative examples. It was calculated. The measurement conditions are CUTOFF:
It was set to 0.8 mm (corresponding to the reference length described above). Conventional Example 1 A rubber mold having a mold surface corresponding to the peripheral surface of a rubber roller, which is processed to correspond to a textured pattern of smoothly continuous irregular waves 9 as shown in FIG. The product is vulcanized and molded under the same conditions and a rubber roller (diameter 24 mm x
A width of 28 mm) was produced. Measurement of friction coefficient The rubber roller of each of the above examples, comparative examples and conventional examples,
Set it in a paper passing tester manufactured by Sumitomo Rubber Industries, Ltd., rotate it under the conditions of a pressure contact force to the paper of 200 g and a roller peripheral speed of 50 mm / sec. The coefficient was measured by the following method. The results are shown in Table 1,
It is shown in FIG.

First, as shown in FIG. 4, a plain paper copy paper 4 having one end connected to the load cell 3 is placed on a pressure-bonding plate 5 made of an acrylic plate, the surface of which is coated with a Teflon sheet or the like to suppress friction. Next, the rubber roller R as a sample is set on the rotary shaft 6 arranged above the pressure bonding plate 5, the pressure bonding plate 5 is moved upward, and the rubber roller R is applied with a predetermined pressure contact force W (g). Abut.
The pressure contact force W (g) indicated by a black arrow in the figure is measured by, for example, a push-pull gauge (not shown) connected to the pressure bonding plate 5.

Then, the rubber roller R is rotated at a constant speed in the direction indicated by the one-dot chain line arrow in the figure to generate a conveying force F in the direction indicated by the white arrow in the figure, which is generated on the plain paper copy sheet 4.
(G) is measured by the load cell 3, and the following formula:

[0029]

(Equation 3)

The friction coefficient is calculated by

[0031]

[Table 1]

[0032]

[Table 2]

From the results in Tables 1 and 2 above, an average R of 5 points
(%) Is less than 30%, 21%, of the rubber roller of Comparative Example 1, conversely, the five-point average R (%) is more than 80%, 85%, of the rubber roller of Comparative Example 2, and the conventional wrinkle pattern of FIG. It was found that all of the rubber rollers of Conventional Example 1 subjected to No. 1 had a low coefficient of friction, and the paper transportability was insufficient. On the other hand, it was found that the rubber rollers of Examples 1 to 5 in which the five-point average R (%) was in the range of 30 to 80% had a high friction coefficient and good paper transportability.

Comparing the examples, the five-point average R
It was also found that the rubber rollers of Examples 3 and 4 in which (%) was in the range of 45 to 65% had a particularly high coefficient of friction and were excellent in paper transportability. Further, comparing Examples 1 and 2 in which the five-point average R (%) is almost the same and the ten-point average roughness is different, Example 2 having a larger ten-point average roughness has a higher friction coefficient and paper. It was found that it has excellent transportability.

[0035]

As described above in detail, since the rubber roller of the present invention has a peculiar grain pattern on its peripheral surface, it excels in the transportability of the paper and, over a long period of time, the above-mentioned good paper is obtained. The peculiar function and effect that the transportability of can be maintained. Therefore, the rubber roller of the present invention is
It can be suitably used for paper feeding in laser beam printers, electrostatic copying machines, facsimiles, ATMs and the like.

[Brief description of drawings]

FIG. 1 (a) is a sectional view showing an example of a grain pattern formed on the peripheral surface of a rubber roller of the present invention, and FIG. 1 (b) is a plan view.

FIG. 2 is a cross-sectional view illustrating deformation of a grain pattern during pressurization.

FIG. 3 is a cross-sectional view showing an example of a conventional embossed pattern.

FIG. 4 is a diagram illustrating an outline of an apparatus for measuring a coefficient of friction of a rubber roller with paper.

[Explanation of symbols]

 1 land area 2 sea area

Claims (1)

[Claims] 1. A rubber roller having a textured pattern formed on a peripheral surface of a rubber roller, the land portion extending along the peripheral surface and a sea portion recessed from the land portion. (X in the formula is a 20 times magnified photograph of a square area of about 6 mm on one side of the roller peripheral surface, and one side is 100 mm.
When the square area of mm is divided into 400 small squares, the number of small squares that do not include the sea area and are all land areas is shown, and Y is the number of small squares in which land areas and sea areas are mixed. Indicates. ) Occupancy rate R (%)
, The average value of the measurement results at multiple points on the roller circumference is 3
A rubber roller characterized by being 0 to 80%.