JP7454047B2 - roll - Google Patents

Description

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

BACKGROUND OF THE INVENTION Office equipment such as copying machines and printers have rolls used for feeding paper, for example. This type of roll is required to have a large conveying force and high wear resistance. For example, Patent Document 1 discloses a paper feeding and conveying roll having an uneven surface.

Japanese Patent Application Publication No. 2002-96938

By the way, when a roll is used for a certain amount of time, the friction coefficient of the roll decreases due to wear of the convex portions on the surface, adhesion of paper powder to the surface, and the like. If the friction coefficient of the roll decreases, problems may occur in paper feeding.

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

In order to solve the above problems, a roll according to one aspect of the present invention is a roll used for paper feeding, and has a surface that contacts paper and has a plurality of convex portions 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 interval between the convex parts in the plurality of convex parts is in the range of 0.6 mm or more and 0.8 mm or less. It is.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a roll according to an embodiment. FIG. 3 is an explanatory diagram for explaining evaluation items and evaluation conditions of paper passing evaluation. FIG. 6 is a diagram showing the results of paper passing evaluation. It is a figure which shows the evaluation result of the cross-sectional area of a convex part. It is a figure showing the evaluation result of a friction coefficient. 2 is an explanatory diagram for explaining the action of the roll shown in FIG. 1. 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. Furthermore, since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are attached thereto. Unless there is a statement to that effect, it is not limited to these forms.

[1. Embodiment]
Embodiments of the present invention will be described below. First, an example of the 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 orthogonal coordinate system having an X axis, a Y axis, and a Z axis that are orthogonal to each other is introduced. Hereinafter, the direction pointed by the X-axis arrow will be referred to as the +X direction, and the direction opposite to the +X direction will be referred to as the -X direction. The direction pointed by the Y-axis arrow is called the +Y direction, and the opposite direction to the +Y direction is called the -Y direction. Further, the direction pointed by the Z-axis arrow is called the +Z direction, and the opposite direction to the +Z direction is called the -Z direction. Furthermore, hereinafter, the +X direction and the -X direction will be referred to as the X direction without any particular distinction, 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 as the Y direction. , may be referred to as the Z direction without particular distinction.

The roll 10 is used, for example, to feed paper or the like. For example, the roll 10 may be any one of a paper feed roll, a separation roll, and a conveyance roll used in office equipment such as copying machines and printers. In this embodiment, it is assumed that the roll 10 is a paper feed roll. The "perspective view" in FIG. 1 is a perspective view showing the entire roll 10. Further, the "schematic diagram of the surface" in FIG. 1 schematically shows a part of the roll 10 (the part that contacts the paper PA) when the roll 10 is viewed from the +Z direction. Note that in the "schematic diagram of the front surface" of FIG. 1, it is assumed that the paper PA is transported in the -X direction (the direction indicated by the broken line arrow). In the following, the direction in which the paper PA is transported is also referred to as the transport direction.

As shown in the "perspective view" of FIG. 1, the roll 10 includes 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 part 14. The shaft member 16 rotates, for example, with a center axis AX along the Z-axis serving as a rotation axis. Therefore, the roll 10 connected to the shaft member 16 rotates as the shaft member 16 rotates. Note that the shaft member 16 may be included in the roll 10. Further, for example, the shaft member 16 and the shaft connection portion 12 may be formed integrally with each other as a structure similar to the shaft connection portion 12 into which the shaft member 16 is inserted.

The shaft connecting portion 12 may be made of, for example, a synthetic resin such as plastic that is harder than rubber, or may be made of a metal material. The rubber portion 14 is made of 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 as a type A hardness based on JIS (Japanese Industrial Standards) K6253. In this case, for example, it is possible to achieve both parameter control by polishing (processability) and wear resistance. Note that the type A hardness indicates hardness measured by a type A durometer based on JIS K6253 (corresponding to ISO 7619). In the following, Type A hardness based on JIS K6253 is also referred to as JISA.

Here, a method of increasing the abrasion resistance by increasing the hardness of the material itself of the rubber portion 14 can be considered. However, increasing the hardness of the material of the rubber portion 14 reduces the nip width, leading to a reduction in the initial coefficient of friction. For this reason, when the hardness of the material itself of the rubber portion 14 is increased, paper feeding efficiency tends to decrease. Further, when a material such as urethane that has high wear resistance and a small decrease in the coefficient of friction is used as the material for the rubber portion 14, the cost tends to increase. That is, in this embodiment, by using EPDM as the material of the rubber part 14, the cost of the roll 10 can be reduced compared to the case of using urethane as the material of the rubber part 14.

Further, as shown in the "schematic diagram of the surface" of FIG. 1, a plurality of grooves 14cc and a plurality of convex portions 14cv are provided on the outer circumferential surface of the rubber portion 14 (the surface of the roll 10). That is, the roll 10 comes into contact with paper such as the 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 (the longitudinal direction of the roll 10), and the convex portions 14cv and the grooves 14cc are arranged alternately. are arranged in Note that the "schematic diagram of the surface" shown in FIG. The present invention is not limited to the example shown in No. 1 "Schematic diagram of surface". 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 vertex P2 and the vertex P1 located in the conveyance direction with respect to the top of the convex portion 14cv (vertex P1 in FIG. 1) when the roll 10 is viewed from the +Z direction. Note that 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 of the outer circumferential 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. Note that the surface roughness Rz of the outer peripheral surface of the rubber portion 14 corresponds to the surface roughness Rz that indicates the degree of unevenness of the surface of the roll 10 (the uneven surface 14c). The surface roughness Rz may be, for example, a ten-point average roughness based on JIS standard B0601 (1994).

Further, the interval S between 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. Below, the interval S between the convex parts 14cv among the plurality of convex parts 14cv is also referred to as the distance S between convex parts. For example, the distance S between the protrusions may be the distance between the top (apex P1) of one of the two protrusions 14cv adjacent to each other and the top (apex P1) of the other protrusion 14cv. good. That is, the distance S between convex portions may be, for example, the average distance between local mountain peaks based on 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, micrometers will also be written as μm, and millimeters will also be written as mm. Furthermore, hereinafter, the ratio of the distance S between the convex portions to the surface roughness Rz (S/Rz) is also referred to as the aspect ratio of the convex portions.

Here, when focusing on one of the plurality of convex portions 14cv, the height of the convex portion 14cv on the X axis (trajectory of side SD) has the following relationship. For example, 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 another position located in the transport direction (−X direction in FIG. 1) with respect to the one position. In addition, when the height of the convex part 14cv at one position on the X axis is lower than the height of the convex part 14cv at another position located in the conveying direction (-X direction in FIG. 1) with respect to the one position. (That is, when the paper PA is transported in the +X direction in FIG. 1), the coefficient of friction between the paper PA and the surface of the roll 10 is smaller than in this embodiment. In other words, in this embodiment, 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 another position located in the conveying direction with respect to the 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 this embodiment, it is possible to suppress deterioration of paper feeding performance.

Next, the results of paper passing evaluation using the roll 10 will be explained with reference to the drawings from FIGS. 2 to 5. Paper passing means, for example, that the paper PA passes through the roll 10 or the like.

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

The items shown in FIG. 2 are evaluated by paper passing evaluation performed in a paper passing environment where the temperature is 10° C. and the humidity is 20%. The device used for paper passing evaluation was 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 based on JIS standard B0601 (1994). The measuring device was Surfcorder SE-500 manufactured by Kosaka Institute 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 the protrusions (unit: mm) is a one-shot 3D shape measuring machine VR-3000 manufactured by Keyence Corporation. The measurement conditions were: the magnification on the monitor was 25 times, and the cutting level in HSC (high spot count) was 33%. For example, the average value of 11 vertical lines in one image x two locations within one line (average value of the distance between convex parts) is calculated as the distance S between convex parts. Specifically, in measuring the distance S between convex parts, 11 vertical lines are drawn at equal intervals for one image of the sample surface, and the HSC and the distance between convex parts are calculated for each vertical line. Then, the average value of the distances between the 11 convex portions is calculated as the distance between the convex portions for one image. Furthermore, images are taken at two locations for each product, and the average value of the distances between the protrusions for the two images is calculated as the distance S between the protrusions. In this evaluation, the high spot count is not particularly measured, but the high spot count is determined when the measurement curve is cut at an arbitrary height (under the measurement conditions shown in Figure 2, the cutting level is 33%). It is the number of parts per unit length that protrude above a given height.

The cross-sectional area AR (unit: mm^2) of the convex portions is calculated from the distance S between the convex portions and the height of the convex portions 14cv using the simple convex model shown in FIG. Note that the symbol ^ indicates a power. The surface roughness Rz is used as the height of the convex portion 14cv. The height Rz0 of the convex portion 14cv in FIG. 2 indicates the surface roughness Rz in the initial state. Further, the cross-sectional area AR0 of the convex portion in FIG. 2 indicates, for example, the cross-sectional area of the convex portion 14cv when the roll 10 in the initial state is cut on 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 abrasion cross-sectional area ARa indicates the cross-sectional area of a portion of the convex cross-sectional area AR0 that is worn out due to paper passage. The abrasion width Wa indicates the width along the X axis of a portion abraded due to paper passing.

The friction coefficient is measured by measuring the friction coefficient by rotating the roll 10 in a counterclockwise direction while applying a load of 2.5N 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 (2.5N) applied to the paper PA. Based on this, the coefficient of friction between the paper PA and the surface of the roll 10 is calculated. The environment in which the coefficient of friction was measured was a temperature of 10° C. and a humidity of 20%.

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

The first sample shown in FIG. 3 is the roll 10 of this 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 addition, below, for convenience of explanation, the four samples from the first comparative sample to the fourth comparative sample will also be explained using the same reference numerals as those given 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° according to JISA. Further, in the first sample, the surface roughness Rz in the initial state is 63 μm, the distance S between the protrusions in the initial state is 0.71 mm, and the aspect ratio (S/Rz) of the protrusions in the initial state is 11.3. It is.

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

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

In addition, in the third comparison sample and the fourth comparison sample, it became impossible to measure the friction coefficient when 30,000 sheets of paper PA were passed, so the evaluation results for up to 30,000 sheets of paper are shown in FIG. .

The cross-sectional area AR of the convex portion when 50,000 sheets of paper PA are passed is smaller than the cross-sectional area AR of the convex portion in the initial state. That is, the cross-sectional area AR of the convex portion decreases as the paper passes through. Note that the cross-sectional area AR of the convex portion of the first sample is larger than the cross-sectional area AR of the convex portion of the other samples both in the initial state and when 50,000 sheets of paper PA are passed.

The friction coefficient when 50,000 sheets of paper PA are passed is smaller than the friction coefficient in the initial state. That is, the coefficient of friction decreases as the paper passes. Note that the friction coefficient of the first sample is smaller than the friction coefficients of the other samples in the initial state, but it is larger than the friction coefficients of the other samples when 50,000 sheets of paper PA are passed through. That is, in the first sample, the decrease in the friction coefficient due to paper passing is suppressed compared to the other samples. In addition, in each number of sheets passed for the friction coefficient in FIG. 3, the numerical value shown in parentheses indicates 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 results of the cross-sectional area AR of the convex portion. The vertical axis in FIG. 4 indicates the cross-sectional area AR (mm^2) of the convex portion, and the horizontal axis indicates the number of sheets to be passed (k sheets).

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

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

The coefficient of friction decreases as the number of sheets passing through increases. In the initial state (the number of sheets 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 passed is 50,000, among the first sample, the first comparison sample, and the second comparison sample, the friction coefficient of the first sample is the largest, and the friction coefficient of the first comparison sample is the smallest. That is, among the first sample, the first comparison sample, and the second comparison sample, the rate of decrease in 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 -34.1%. The rate is -66.0%.

In this way, in the first sample of the present embodiment, even if the number of sheets to be passed increases, the friction coefficient can maintain a large state. That is, in this embodiment, it is possible to suppress a decrease in the coefficient of friction.

Focusing on the surface roughness Rz, the evaluation results of the first sample with a surface roughness Rz of 63 μm and the second comparative sample with a surface roughness Rz of 35 μm show that the larger the surface roughness Rz, the lower the friction coefficient. It can be seen that it is suppressed. Therefore, the surface roughness Rz is preferably 50 μm or more, which is greater than 35 μm. Also, focusing on the distance S between convex parts, from the evaluation results of the first comparison sample with the distance S between convex parts of 0.85 mm and the second comparison sample with the distance S between convex parts of 0.7 mm, the distance between convex parts It can be seen that the smaller S is, the more the reduction 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 in an initial state of 50 μm or more and 80 μm or less, and a distance S between convex parts in an initial state of 0.6 mm or more and 0.8 mm or less. It is formed such that the first condition is satisfied. In addition, when focusing on suppressing the decrease in the coefficient of friction in the combination of the surface roughness Rz and the distance S between the convex parts that satisfy the first condition, when the surface roughness Rz is 50 μm and the distance S between the convex parts is 0.8 mm, It is thought that a certain combination has the least effect of suppressing a decrease in the coefficient of friction. Therefore, in addition to the first condition, by adding the 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 improved. It is thought that it can be obtained with certainty. Therefore, in this embodiment, the roll 10 is formed so that both the second condition that the convex aspect ratio (S/Rz) is in the range of 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. 1. Note that FIG. 6 shows a schematic diagram of the surface of the roll 10 and a schematic diagram 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 cross-sectional area AR of the protrusions is larger than the cross-sectional area AR of the protrusions of the roll 10Z. As a result, the roll 10 can maintain a state in which the cross-sectional area AR of the convex portion is large even when paper is passed. Therefore, in the roll 10, it is possible to suppress a decrease in the coefficient of friction compared to the roll 10Z.

Further, in the roll 10, since the distance S between the convex parts is smaller than the distance S between the convex parts of the roll 10Z, the number of contact parts between the paper PA and the roll 10 per predetermined length L is The number of contact parts between the paper PA and the roll 10Z is greater than the number of contact parts 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. Thereby, in the roll 10, the pressure per unit area applied to the convex portion 14cv can be made smaller than that in the roll 10Z. Therefore, in the roll 10, compared to the roll 10Z, it can be expected that the progression of wear due to paper passing through the convex portions 14cv (that is, the rate of decrease in the convex portions 14cv) is slowed down.

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 greater than that of the roll 10Z. As a result, the roll 10 can improve the paper dust trapping effect of trapping paper dust and the like in the grooves 14cc, compared to the roll 10Z. In addition, 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 two mutually adjacent convex parts 14cv) is equal to the volume of the groove 14cc of the roll 10Z. It becomes larger than the volume. As a result, in the roll 10, compared to the roll 10Z, it is possible to suppress a decrease in paper feeding performance due to clogging of the grooves 14cc with paper powder, etc. That is, in the roll 10, it is possible to improve the paper dust trapping effect while suppressing a decrease in paper feeding performance due to paper dust etc. clogging the grooves 14cc.

As described above, in this embodiment, the roll 10 used for paper feeding has a surface (uneven surface 14c) that comes into 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 interval S between the plurality of convex portions 14cv (distance S between convex portions) among 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 this embodiment, since the surface roughness Rz is in the range of 50 μm or more and 80 μm or less, and the interval S between the convex portions 14cv 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 14cv having a large cross-sectional area AR) can be formed. Thereby, in this embodiment, even when paper is passed, the cross-sectional area of the convex portion 14cv (the cross-sectional area AR of the convex portion) can be maintained large. As a result, in this embodiment, it is possible to suppress a decrease in the coefficient of friction of the roll 10.

Further, in this embodiment, the ratio of the interval S between 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 this embodiment, the first condition is that the surface roughness Rz is in the range of 50 μm or more and 80 μm or less, and the interval S between the convex portions 14cv 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 portions 14cv to the distance S is in a range of 7.5 or more and 14 or less is satisfied.

As a result, in this embodiment, from among the combinations of the surface roughness Rz and the spacing S of the convex portions 14cv that satisfy the first condition, combinations that are considered to reduce the effect of suppressing the decrease in the coefficient of friction (for example, when the surface roughness Rz is 50 μm and the spacing S between the convex portions 14cv is 0.8 mm, etc.) are omitted. As a result, in this embodiment, it is possible to reliably obtain the effect of suppressing a decrease in the coefficient of friction.

Further, in this embodiment, the material forming the surface of the roll 10 (the material of the rubber portion 14) is EPDM. Thereby, in this embodiment, the cost of the roll 10 can be reduced compared to the case where an expensive material such as urethane is used as the material forming the surface of the roll 10.

Further, in this embodiment, the hardness of the EPDM forming the surface of the roll 10 is in the range of 30° or more and 50° or less according to JISA. As a result, in this embodiment, it is possible to achieve both parameter control through polishing (workability) and wear resistance.

[2. Modified example]
The embodiments illustrated above may be modified in various ways. Specific modifications that can be applied to the above-described embodiments are illustrated below. Two or more aspects arbitrarily selected from the following examples may be combined to the extent that they do not contradict each other.

[First modification]
In the embodiment described above, the case where the second condition that the convex aspect ratio (S/Rz) is in the range of 7.5 or more and 14 or less is exemplified, but the present invention is limited to such an aspect. isn't 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 parts 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 neither the first condition nor the second condition is satisfied. It can be expected that the effect of suppressing the decrease in the coefficient of friction will be greater than when the conditions are not satisfied.

[Second modification]
In the embodiment and the first modification described above, the case where the material of the rubber portion 14 is EPDM is illustrated, 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, if an increase in cost is acceptable, a material containing urethane may be used as the material for the rubber portion 14. Even in the second modification, the same effects as in the above-described embodiment can be obtained.

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

10, 10Z...roll, 12...shaft connection part, 14...rubber part, 14c...uneven surface, 14cc...groove, 14cv...convex part, 16...shaft member, 100...load cell, 102...aluminum plate, AR...convex section Area, HL...Shaft hole, PA...Paper, Rz...Surface roughness, S...Distance between convex parts.

Claims (5)

A roll used for paper feeding,
having a surface in contact with the paper and having a plurality of protrusions and a plurality of grooves;
Surface roughness indicating the degree of unevenness caused by the plurality of convex portions and the plurality of grooves on the surface is in a range of 50 micrometers or more and 80 micrometers or less,
The interval between the convex parts in the plurality of convex parts is in the range of 0.6 mm or more and 0.8 mm or less,
A roll characterized by: The ratio of the interval 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, characterized in that: The material forming the surface is EPDM (ethylene propylene diene rubber),
The roll according to claim 1 or 2, characterized in that: The hardness of the EPDM is Type A hardness according 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, characterized in that: Among the plurality of protrusions, the height of one protrusion at one position is higher than the height of the one protrusion at another position located in the conveying direction with respect to the one position.
The roll according to any one of claims 1 to 4, characterized in that:

Images