WO2022004118A1

WO2022004118A1 - Roll

Info

Publication number: WO2022004118A1
Application number: PCT/JP2021/017232
Authority: WO
Inventors: 正明八木; 憲司佐々木; 直矢今関
Original assignee: Nok株式会社
Priority date: 2020-07-03
Filing date: 2021-04-30
Publication date: 2022-01-06
Also published as: JPWO2022004118A1; JP7454047B2; CN115916675A

Abstract

This roll, which is used in feeding sheets, has a surface that comes into contact with paper and has a plurality of protrusions and a plurality of grooves. The surface roughness representing the degree of protrusions and grooves on the surface is within the range of 50 to 80 μm (inclusive), and the pitch of the plurality of protrusions is within the range of 0.6-0.8 millimeters (inclusive).

Description

roll

The present invention relates to a roll used for feeding paper.

Office equipment such as copiers and printers have rolls used for paper feeding such as paper feeding, for example. This type of roll is required to have a large carrying force and a high wear resistance. For example, Patent Document 1 discloses a paper feed transport roll having irregularities on its surface.

Japanese Unexamined Patent Publication No. 2002-96938

By the way, when the roll is used to some extent, the coefficient of friction of the roll decreases due to wear of the convex portion of the surface and adhesion of paper dust to the surface. If the coefficient of friction of the roll decreases, problems may occur in the paper feed.

In consideration of the above circumstances, it is an object of the present invention to suppress a decrease in the friction coefficient of the roll.

In order to solve the above problems, the roll according to one aspect of the present invention is a roll used for feeding paper, and has a surface that comes into contact with paper and has a plurality of protrusions and a plurality of grooves. The surface roughness indicating the degree of unevenness of the surface is in the range of 50 micrometers or more and 80 micrometers or less, and the distance between the convex portions in the plurality of convex portions is in the range of 0.6 mm or more and 0.8 mm or less. Is.

It is explanatory drawing which illustrates the schematic structure of the roll which concerns on embodiment. It is explanatory drawing for demonstrating the evaluation item and the evaluation condition of the paper passing evaluation. It is a figure which shows the result of the paper passing evaluation. It is a figure which shows the evaluation result of the convex part cross-sectional area. It is a figure which shows the evaluation result of the friction coefficient. It is explanatory drawing for demonstrating the action of the roll shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, in each figure, the dimensions and scale of each part are appropriately different from the actual ones. Further, since the embodiments described below are suitable specific examples of the present invention, various technically preferable limitations are attached, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, it is not limited to these forms.

[1. Embodiment]
Hereinafter, embodiments of the present invention will be described. First, an example of an outline of the roll 10 according to the embodiment will be described with reference to FIG.

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a roll 10 according to an embodiment.

In this embodiment, for convenience of explanation, a three-axis Cartesian coordinate system having an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other is introduced. In the following, the direction pointed by the arrow on the X axis is referred to as the + X direction, and the direction opposite to the + X direction is referred to as the −X direction. The direction pointed by the arrow on the Y axis is referred to as the + Y direction, and the direction opposite to the + Y direction is referred to as the −Y direction. Further, the direction pointed by the arrow on the Z axis is referred to as the + Z direction, and the direction opposite to the + Z direction is referred to as the −Z direction. Further, in the following, the + X direction and the −X direction will be referred to as the X direction without particular distinction, and the + Y direction and the −Y direction will be referred to as the Y direction without any particular distinction, and the + Z direction and the −Z direction will be referred to. , It may be referred to as the Z direction without particular distinction.

The roll 10 is used for paper feeding such as feeding, for example. For example, the roll 10 may be any of a paper feed roll, a separation roll, and a transport roll used in office equipment such as copiers and printers. In this embodiment, it is assumed that the roll 10 is a paper feed roll. The “perspective view” of FIG. 1 is a perspective view showing the entire roll 10. Further, the "schematic view of the surface" of FIG. 1 schematically shows a part of the roll 10 (a portion in contact with the paper PA) when the roll 10 is viewed from the + Z direction. In the "schematic surface diagram" of FIG. 1, it is assumed that the paper PA is conveyed in the −X direction (the direction indicated by the arrow of the broken line). Hereinafter, the direction in which the paper PA is conveyed is also referred to as a transfer direction.

As shown in the "perspective view" of FIG. 1, the roll 10 has a shaft connecting portion 12 provided with a shaft hole HL into which a rotating shaft member 16 is inserted, and a cylindrical shape provided around the shaft connecting portion 12. It has a rubber portion 14 of the above. The shaft member 16 rotates, for example, with the central axis AX along the Z axis as a rotation axis. Therefore, the roll 10 connected to the shaft member 16 rotates as the shaft member 16 rotates. The shaft member 16 may be included in the roll 10. Further, for example, the shaft member 16 and the shaft connecting portion 12 may be integrally formed with each other as a structure similar to the shaft connecting portion 12 into which the shaft member 16 is inserted.

The shaft connection portion 12 may be formed of, for example, a synthetic resin such as plastic harder than rubber, or may be formed of a metal material. The rubber portion 14 is formed of, for example, an elastic material such as EPDM (ethylene propylene diene rubber). For example, the hardness of EPDM may be in the range of 30 ° or more and 50 ° or less in Type A hardness conforming to JIS (Japanese Industrial Standards) K6253. In this case, for example, it is possible to achieve both the ability to control parameters by polishing (workability) and wear resistance. The type A hardness indicates the hardness measured by the type A durometer based on JIS K6253 (corresponding to ISO 7619). In the following, the type A hardness conforming to JIS K6253 is also referred to as JIS A.

Here, a method of increasing the wear resistance by increasing the hardness of the material itself of the rubber portion 14 can be considered. However, increasing the hardness of the material itself of the rubber portion 14 reduces the nip width, which leads to a decrease in the initial friction coefficient. Therefore, when the hardness of the material itself of the rubber portion 14 is increased, the paper feeding efficiency tends to decrease. Further, when a material such as urethane having high wear resistance and a small decrease in the coefficient of friction is used as the material of the rubber portion 14, the cost tends to be high. That is, in the present embodiment, by using EPDM as the material of the rubber portion 14, the cost of the roll 10 can be reduced as compared with the case where urethane is used as the material of the rubber portion 14.

Further, as shown in the "schematic surface diagram" of FIG. 1, a plurality of grooves 14cc and a plurality of convex portions 14cv are provided on the outer peripheral surface (surface of the roll 10) of the rubber portion 14. That is, the roll 10 is in contact with paper such as paper PA and has an uneven surface 14c having a plurality of convex portions 14cv and a plurality of grooves 14cc. For example, in the uneven surface 14c shown in FIG. 1, each of the plurality of convex portions 14cv and each of the plurality of grooves 14cc extend in the Z direction (longitudinal direction of the roll 10), and the convex portions 14cv and the grooves 14cc alternate. Are arranged in. The "schematic surface diagram" shown in FIG. 1 is a schematic diagram for explaining the interval S of the convex portions 14cv and the surface roughness Rz, which will be described later, in an easy-to-understand manner, and the actual surface shape of the roll 10 is shown in the figure. It is not limited to the example shown in 1 "schematic surface diagram". For example, the side SD of the convex portion 14cv when the roll 10 is viewed from the + Z direction may be a curved line. The side SD is a line connecting the apex P2 located in the transport direction with respect to the apex (vertex P1 in FIG. 1) of the convex portion 14cv when the roll 10 is viewed from the + Z direction, and the apex P1. When focusing on the two convex portions 14cv adjacent to each other, the apex P3 of one convex portion 14cv of the two convex portions 14cv is also the apex P2 of the other convex portion 14cv of the two convex portions 14cv.

The surface roughness Rz, which indicates the degree of unevenness on the outer peripheral surface of the rubber portion 14, is in the range of 50 micrometers or more and 80 micrometers or less in the initial state. The initial state is, for example, an unused state before the roll 10 is attached to office equipment. The surface roughness Rz of the outer peripheral surface of the rubber portion 14 corresponds to the surface roughness Rz indicating the degree of unevenness on the surface (concave and convex surface 14c) of the roll 10. The surface roughness Rz may be, for example, a ten-point average roughness conforming to JIS standard B0601 (1994).

Further, the interval S of the convex portions 14cv in the plurality of convex portions 14cv included in the uneven surface 14c is in the range of 0.6 mm or more and 0.8 mm or less in the initial state. In the following, the distance S between the convex portions 14cv in the plurality of convex portions 14cv is also referred to as the distance between the convex portions S. For example, the inter-convex distance S may be the distance between the top of one convex portion 14cv (vertex P1) and the top of the other convex portion 14cv (vertex P1) of two adjacent convex portions 14cv. good. That is, the distance S between the convex portions may be, for example, the average distance of the local peaks according to JIS standard B0601 (1994). Further, the ratio (S / Rz) of the distance S between the convex portions to the surface roughness Rz is in the range of 7.5 or more and 14 or less. In the following, micrometer is also referred to as μm, and millimeter is also referred to as mm. Further, in the following, the ratio (S / Rz) of the distance S between the convex portions to the surface roughness Rz is also referred to as a convex portion aspect ratio.

Here, when focusing on the convex portion 14cv of one of the plurality of convex portions 14cv, the height of the convex portion 14cv on the X-axis (trajectory of the side SD) has the following relationship. For example, the height of the convex portion 14cv at one position on the X-axis is lower than the height of the convex portion 14cv at the other position located in the transport direction (-X direction in FIG. 1) with respect to one position. When the height of the convex portion 14cv at one position on the X-axis is higher than the height of the convex portion 14cv at the other position located in the transport direction (-X direction in FIG. 1) with respect to one position. (That is, in FIG. 1, when the paper PA is conveyed in the + X direction), the coefficient of friction between the paper PA and the surface of the roll 10 becomes smaller than that of the present embodiment. In other words, in the present embodiment, the height of the convex portion 14cv at one position on the X-axis is higher than the height of the convex portion 14cv at the other position located in the transport direction with respect to one position. Therefore, the coefficient of friction between the paper PA and the surface of the roll 10 can be increased. As a result, in the present embodiment, it is possible to prevent the paper feed performance from deteriorating.

Next, the result of the paper passing evaluation using the roll 10 will be described with reference to the drawings of FIGS. 2 to 5. The paper passing is, for example, the paper PA passing through the roll 10 or the like.

FIG. 2 is an explanatory diagram for explaining the evaluation items and evaluation conditions of the paper passing evaluation.

The items shown in FIG. 2 are evaluated by a paper passing evaluation carried out in a paper passing environment where the temperature is 10 ° C. and the humidity is 20%. The device used for the paper passing evaluation is a color printer (DocuPrint C5000d) manufactured by Fuji Xerox Co., Ltd.

As described above, the surface roughness Rz (unit: μm) is a ten-point average roughness conforming to JIS standard B0601 (1994). The measuring device is a surf coder SE-500 manufactured by Kosaka Laboratory Co., Ltd. The measurement conditions are a cutoff of 0.8, a measurement length of 8 mm, and a measurement speed of 0.1 mm / sec.

The measuring device for the distance S between protrusions (unit: mm) is a one-shot 3D shape measuring machine VR-3000 manufactured by KEYENCE CORPORATION. As the measurement conditions, the magnification on the monitor is 25 times, and the cutting level in HSC (high spot count) is 33%. For example, the average value (average value of the distance between the convex portions) of 11 vertical lines in one image × 2 places in one is calculated as the distance S between the convex portions. Specifically, in the measurement of the inter-convex distance S, 11 vertical lines are drawn at equal intervals for each image of the sample surface, and the HSC and the inter-convex distance are calculated for each vertical line. Then, the average value of the distances between the 11 convex portions is calculated as the interconvex distances for one image. Further, each product is photographed at two locations, and the average value of the distances between the convex portions for the two images is calculated as the distance between the convex portions S. In this evaluation, the high spot count is not particularly measured, but the high spot count is cut when the measurement curve is cut at an arbitrary height (cutting level is 33% under the measurement conditions shown in FIG. 2). It is the number of parts protruding above an arbitrary height per unit length.

The convex portion cross-sectional area AR (unit: mm ^ 2) is calculated by the convex portion distance S and the height of the convex portion 14 cv using the convex portion simplified model shown in FIG. The sign ^ indicates a power. Surface roughness Rz is used as the height of the convex portion 14 cv. The height Rz0 of the convex portion 14cv in FIG. 2 indicates the surface roughness Rz in the initial state. Further, the convex portion cross-sectional area AR0 in FIG. 2 shows, for example, the cross-sectional area of the convex portion 14cv when the roll 10 in the initial state is cut in a plane parallel to the XY plane including the X-axis and the Y-axis. That is, the convex cross-sectional area AR0 indicates the convex cross-sectional area AR in the initial state. The wear cross-sectional area ARa indicates the cross-sectional area of the portion of the convex cross-sectional area AR0 that has been worn by passing paper. The wear width Wa indicates the width along the X-axis of the portion worn by the paper passing.

As shown in the schematic diagram of the measurement method, the coefficient of friction is a line counterclockwise on the roll 10 with a load of 2.5 N applied to the paper PA set between the roll 10 and the aluminum plate 102. It is measured by rotating at a speed of 300 mm / sec. For example, the measured value of the load cell 100 (force in the X direction applied to the paper PA) obtained when the roll 10 is rotated counterclockwise at a linear speed of 300 mm / sec and the load applied to the paper PA (2.5N). Based on this, the coefficient of friction between the paper PA and the surface of the roll 10 is calculated. As a measurement environment for the coefficient of friction, the temperature is 10 ° C. and the humidity is 20%.

FIG. 3 is an explanatory diagram showing the result of the paper passing evaluation.

The first sample shown in FIG. 3 is the roll 10 of the present embodiment. Note that FIG. 3 also shows the results of paper passing evaluation using four samples from the first comparative sample to the fourth comparative sample as a comparative example of the present embodiment. In the following, for convenience of explanation, the four samples from the first comparison sample to the fourth comparison sample will also be described using the same reference numerals as those attached to the roll 10.

In the first sample, the material of the rubber portion 14 is EPDM, and the hardness of the rubber portion 14 is 35 ° in JIS A. Further, in the first sample, the surface roughness Rz in the initial state is 63 μm, the distance S between the convex portions in the initial state is 0.71 mm, and the convex portion aspect ratio (S / Rz) in the initial state is 11.3. Is.

In the first comparative sample and the second comparative sample, the material and hardness of the rubber portion 14 are the same as those of the first sample. In the first comparative sample, the surface roughness Rz in the initial state is 32 μm, the distance S between the convex portions in the initial state is 0.85 mm, and the convex portion aspect ratio (S / Rz) in the initial state is 26. It is 6. Further, in the second comparative sample, the surface roughness Rz in the initial state is 35 μm, the distance S between the convex portions in the initial state is 0.7 mm, and the convex portion aspect ratio (S / Rz) in the initial state is 20. be.

In the third comparative sample and the fourth comparative sample, the material of the rubber portion 14 is the same as that of the first sample, but the hardness of the rubber portion 14 is 25 °, which is lower than the hardness of the rubber portion 14 of the first sample. Further, in the third comparative sample, the surface roughness Rz in the initial state is 38 μm, the distance S between the convex portions in the initial state is 0.88 mm, and the convex portion aspect ratio (S / Rz) in the initial state is 23. It is 2. Further, in the fourth comparative sample, the surface roughness Rz in the initial state is 36 μm, the distance S between the convex portions in the initial state is 0.69 mm, and the convex portion aspect ratio (S / Rz) in the initial state is 19. It is 2.

In the third comparison sample and the fourth comparison sample, since the friction coefficient when 30,000 sheets of paper PA were passed could not be measured, the evaluation results up to 30,000 sheets of paper were shown in FIG. ..

The convex cross-sectional area AR when 50,000 sheets of paper PA are passed is smaller than the convex cross-sectional area AR in the initial state. That is, the convex cross-sectional area AR is reduced by passing paper. The convex cross-sectional area AR of the first sample is larger than the convex cross-sectional area AR of the other samples both in the initial state and when 50,000 sheets of paper PA are passed.

The coefficient of friction when 50,000 sheets of paper PA are passed is smaller than the coefficient of friction in the initial state. That is, the coefficient of friction is reduced by passing paper. The coefficient of friction of the first sample is smaller than the coefficient of friction of the other samples in the initial state, but is larger than the coefficient of friction of the other samples when 50,000 sheets of paper PA are passed. That is, in the first sample, the decrease in the coefficient of friction due to paper passing is suppressed as compared with the other samples. In addition, in each number of sheets of the friction coefficient of FIG. 3, the numerical value shown in parentheses shows the reduction rate of the friction coefficient with respect to the friction coefficient in the initial state.

FIG. 4 is a diagram showing the evaluation result of the convex cross-sectional area AR. The vertical axis of FIG. 4 indicates the convex cross-sectional area AR (mm ^ 2), and the horizontal axis indicates the number of sheets to be passed (k sheets).

The convex cross-sectional area AR of the first sample decreases as the number of sheets to be passed increases. Further, the convex cross-sectional area AR of the first sample is in the initial state (the number of sheets to be passed is 0), the number of sheets to be passed is 15,000, the number of sheets to be passed is 30,000, and the number of sheets to be passed is 50,000. It is larger than the convex cross-sectional area AR of the first comparative sample and the convex cross-sectional area AR of the second comparative sample. As shown in FIG. 4, in the first sample of the present embodiment, it is possible to maintain a state in which the convex cross-sectional area AR is large even if the number of sheets to be passed increases. As a result, in the present embodiment, as shown in FIG. 5, it is possible to suppress a decrease in the friction coefficient.

FIG. 5 is a diagram showing the evaluation result of the friction coefficient. The vertical axis of FIG. 5 shows the coefficient of friction, and the horizontal axis shows the number of sheets to be passed (k sheets).

The coefficient of friction decreases as the number of sheets to be passed increases. In the initial state (the number of sheets to be passed is 0), the friction coefficient of the first comparison sample is the largest and the friction coefficient of the first sample is the smallest among the first sample, the first comparison sample and the second comparison sample. When the number of sheets to be passed is 50,000, the friction coefficient of the first sample is the largest and the friction coefficient of the first comparison sample is the smallest among the first sample, the first comparison sample and the second comparison sample. That is, among the first sample, the first comparison sample, and the second comparison sample, the reduction rate of the friction coefficient of the first sample is the smallest. For example, the reduction rate of the friction coefficient of the first sample is -34.1%, the reduction rate of the friction coefficient of the second comparison sample is -55.9%, and the reduction rate of the friction coefficient of the first comparison sample is -55.9%. The rate is -66.0%.

As described above, in the first sample of the present embodiment, the state in which the friction coefficient is large can be maintained even if the number of sheets to be passed increases. That is, in the present embodiment, it is possible to suppress a decrease in the coefficient of friction.

Focusing on the surface roughness Rz, from the evaluation results of the first sample having a surface roughness Rz of 63 μm and the second comparative sample having a surface roughness Rz of 35 μm, the larger the surface roughness Rz, the lower the coefficient of friction. It turns out that it is suppressed. Therefore, the surface roughness Rz is preferably 50 μm or more, which is larger than 35 μm. Focusing on the inter-convex distance S, the distance between the convex portions is based on the evaluation results of the first comparative sample having the inter-convex distance S of 0.85 mm and the second comparative sample having the inter-convex distance S of 0.7 mm. It can be seen that the smaller S is, the more the decrease in the friction coefficient is suppressed. Therefore, the distance S between the convex portions is preferably 0.8 mm or less, which is smaller than 0.85 mm.

Therefore, in the present embodiment, the roll 10 has a surface roughness Rz of 50 μm or more and 80 μm or less in the initial state, and a protrusion-to-convex distance S of 0.6 mm or more and 0.8 mm or less in the initial state. It is formed so that the first condition is satisfied. Further, in the combination of the surface roughness Rz and the inter-convex distance S satisfying the first condition, when focusing on suppressing the decrease in the friction coefficient, the surface roughness Rz is 50 μm and the inter-convex distance S is 0.8 mm. It is considered that a certain combination has the least effect of suppressing the decrease in the coefficient of friction. Therefore, in addition to the first condition, by adding a condition that the convex aspect ratio (S / Rz) is 14 or less, which is smaller than 16 (= 0.8 mm / 50 μm), the effect of suppressing the decrease in the friction coefficient can be obtained. It is considered that it can be surely obtained. Therefore, in the present embodiment, the roll 10 is formed so that both the second condition in which the convex aspect ratio (S / Rz) is 7.5 or more and 14 or less and the first condition are satisfied. ..

FIG. 6 is an explanatory diagram for explaining the action of the roll 10 shown in FIG. Note that FIG. 6 shows a schematic view of the surface of the roll 10 and a schematic view of the surface of the first comparative sample described above. In the following, the first comparative sample is also referred to as roll 10Z.

In the roll 10, since the surface roughness Rz is larger than the surface roughness Rz of the roll 10Z, the convex cross-sectional area AR is larger than the convex cross-sectional area AR of the roll 10Z. As a result, the roll 10 can maintain a state in which the convex cross-sectional area AR is large even when the paper is passed. Therefore, in the roll 10, it is possible to suppress the decrease in the friction coefficient as compared with the roll 10Z.

Further, in the roll 10, since the distance S between the convex portions is smaller than the distance S between the convex portions of the roll 10Z, the number of contact portions between the paper PA and the roll 10 per the predetermined length L is per predetermined length L. It is larger than the number of contact portions between the paper PA and the roll 10Z. That is, in the roll 10, the contact area between the paper PA and the rubber portion 14 is larger than that in the roll 10Z. As a result, in the roll 10, the pressure per unit area applied to the convex portion 14cv can be reduced as compared with the roll 10Z. Therefore, in the roll 10, it can be expected that the progress of wear due to the passing of the convex portion 14 cv (that is, the decrease rate of the convex portion 14 cv) is slower than that in the roll 10Z.

Further, in the roll 10, since the distance S between the convex portions is smaller than the distance S between the convex portions of the roll 10Z, the number of grooves 14cc per predetermined length L is larger than that of the roll 10Z. As a result, the roll 10 can improve the paper dust trapping effect of trapping the paper dust or the like in the groove 14 cc as compared with the roll 10Z. Since the surface roughness Rz of the roll 10 is larger than the surface roughness Rz of the roll 10Z, the volume of the groove 14cc (the volume of the space between the two convex portions 14cv adjacent to each other) is the volume of the groove 14cc of the roll 10Z. It will be larger than the volume. As a result, in the roll 10, compared to the roll 10Z, it is possible to suppress deterioration of the paper feed performance due to clogging of the groove 14cc with paper dust or the like. That is, in the roll 10, it is possible to improve the paper dust trapping effect and suppress the deterioration of the paper feed performance due to the paper dust or the like being clogged in the groove 14 cc.

As described above, in the present embodiment, the roll 10 used for feeding paper has a surface (concave and convex surface 14c) which is in contact with paper such as paper PA and has a plurality of convex portions 14cv and a plurality of grooves 14cc. The surface roughness Rz, which indicates the degree of surface unevenness, is in the range of 50 μm or more and 80 μm or less. Further, the distance S (distance S between convex portions) of the convex portions 14cv in the plurality of convex portions 14cv included in the uneven surface 14c is in the range of 0.6 mm or more and 0.8 mm or less.

As described above, in the present embodiment, since the surface roughness Rz is in the range of 50 μm or more and 80 μm or less and the interval S of the convex portions 14 cv is in the range of 0.6 mm or more and 0.8 mm or less, the cross-sectional area (convex portion). A convex portion 14 cv having a large cross-sectional area AR) can be formed. Thereby, in the present embodiment, it is possible to maintain a state in which the cross-sectional area of the convex portion 14 cv (convex cross-sectional area AR) is large even when the paper is passed. As a result, in the present embodiment, it is possible to prevent the friction coefficient of the roll 10 from decreasing.

Further, in the present embodiment, the ratio of the interval S of the plurality of convex portions 14cv to the surface roughness Rz is in the range of 7.5 or more and 14 or less. That is, in the present embodiment, the first condition that the surface roughness Rz is in the range of 50 μm or more and 80 μm or less and the interval S of the convex portions 14 cv is in the range of 0.6 mm or more and 0.8 mm or less, and the surface roughness Rz. The second condition that the ratio of the interval S of the convex portion 14 cv to the above is in the range of 7.5 or more and 14 or less is satisfied.

As a result, in the present embodiment, the combination of the surface roughness Rz satisfying the first condition and the interval S of the convex portions 14cv is considered to reduce the effect of suppressing the decrease in the friction coefficient (for example, the surface roughness Rz). A combination in which the distance S between the convex portions 14 cv is 0.8 mm at 50 μm) is omitted. As a result, in the present embodiment, the effect of suppressing the decrease in the coefficient of friction can be surely obtained.

Further, in the present embodiment, the material (material of the rubber portion 14) forming the surface of the roll 10 is EPDM. Thereby, in the present embodiment, the cost of the roll 10 can be reduced as compared with the case where a high cost material such as urethane is used as the material forming the surface of the roll 10.

Further, in the present embodiment, the hardness of EPDM forming the surface of the roll 10 is in the range of 30 ° or more and 50 ° or less in JIS A. Thereby, in the present embodiment, it is possible to achieve both the parameter control by polishing (workability) and the wear resistance.

[2. Modification example]
The embodiments exemplified above can be variously modified. Specific embodiments that may be applied to the above-described embodiments are illustrated below. Two or more embodiments arbitrarily selected from the following examples may be merged to the extent that they do not contradict each other.

[First modification]
In the above-described embodiment, the case where the second condition in which the convex aspect ratio (S / Rz) is in the range of 7.5 or more and 14 or less is satisfied has been exemplified, but the present invention is limited to such an embodiment. is not it. For example, if the first condition that the surface roughness Rz in the initial state is in the range of 50 μm or more and 80 μm or less and the distance S between the convex portions in the initial state is in the range of 0.6 mm or more and 0.8 mm or less is satisfied. , The second condition may not be satisfied. In this case, the effect of suppressing the decrease in the coefficient of friction may be smaller than when both the first condition and the second condition are satisfied, but both the first condition and the second condition are available. It can be expected that the effect of suppressing the decrease in the coefficient of friction will be greater than in the case where it is not satisfied.

[Second modification]
In the above-described embodiment and the first modification, the case where the material of the rubber portion 14 is EPDM is exemplified, but the present invention is not limited to such an embodiment. For example, the material of the rubber portion 14 may be an elastic material other than EPDM. Specifically, the material of the rubber portion 14 may be an elastic material such as VMQ (vinyl methyl silicone rubber) and FKM (fluororubber). Further, for example, when it is permissible to increase the cost, a material containing urethane may be used as the material of the rubber portion 14. Also in the second modification, the same effect as that of the above-described embodiment can be obtained.

[Third modification example]
In the above-described embodiment, the first modification and the second modification, the case where the hardness of the rubber portion 14 is in the range of 30 ° or more and 50 ° or less in JIS A is exemplified, but the present invention is limited to such an embodiment. It's not something. The hardness of the rubber portion 14 may be any hardness as long as it can achieve both workability and wear resistance. For example, the hardness of the rubber portion 14 may be 29 ° in JIS A or 51 ° in JIS A. Also in the third modification, the same effect as that of the above-described embodiment can be obtained.

10, 10Z ... Roll, 12 ... Shaft connection part, 14 ... Rubber part, 14c ... Concavo-convex surface, 14cc ... Groove, 14cv ... Convex part, 16 ... Shaft member, 100 ... Load cell, 102 ... Aluminum plate, AR ... Convex part break Area, HL ... shaft hole, PA ... paper, Rz ... surface roughness, S ... distance between convex parts.

Claims

A roll used for paper feeding,
It has a surface that comes in contact with paper and has multiple protrusions and multiple grooves.
The surface roughness indicating the degree of unevenness of the surface is in the range of 50 micrometers or more and 80 micrometers or less.
The distance between the convex portions in the plurality of convex portions is in the range of 0.6 mm or more and 0.8 mm or less.
A roll characterized by that.
The ratio of the distance between the convex portions to the surface roughness is in the range of 7.5 or more and 14 or less.
The roll according to claim 1.
The material forming the surface is EPDM (ethylene propylene diene rubber).
The roll according to claim 1 or 2, wherein the roll is characterized by the above.
The hardness of EPDM is a type A hardness conforming to JIS (Japanese Industrial Standards) K6253 and is in the range of 30 ° or more and 50 ° or less.
The roll according to claim 3.