CN111032544A

CN111032544A - Paper feeding roller

Info

Publication number: CN111032544A
Application number: CN201880052090.5A
Authority: CN
Inventors: 山口和志; 高岛雅彦; 小濑峻久; 河野淳洋
Original assignee: Sumitomo Riko Co Ltd
Current assignee: Sumitomo Riko Co Ltd
Priority date: 2017-08-31
Filing date: 2018-07-31
Publication date: 2020-04-17
Anticipated expiration: 2038-07-31
Also published as: WO2019044330A1; US20200055683A1; CN111032544B

Abstract

The invention provides a paper feed roller capable of restraining poor paper conveying caused by paper powder accumulation for a long time. The paper feed roller 10 includes a shaft body 12 and an elastic body layer 14 formed on the outer periphery of the shaft body 12, wherein the peripheral surface of the elastic body layer 14 is provided with projections and recesses by projections 16, the projections 16 are arranged along the peripheral surface of the elastic body layer 14 in a direction different from the axial direction X, a groove 18 of a continuous recess is formed between a row of the projections 16 in the direction different from the axial direction X and a row of the projections 16 parallel to the row, and the width of the groove 18 is larger than the distance of separation of the projections in the row of the projections 16 in the direction different from the axial direction X.

Description

Paper feeding roller

Technical Field

The present invention relates to a paper feed roller suitable for use in an electrophotographic apparatus such as a copying machine, a printer, and a facsimile machine which employ an electrophotographic method.

Background

The paper feed roller is formed in a cylindrical shape from an elastic material such as a crosslinked rubber, and the peripheral surface thereof is a contact surface with the paper. Paper dust generated from paper may adhere to the peripheral surface of the paper feed roller. Further, paper dust may accumulate on the circumferential surface of the paper feed roller during repeated contact with the paper. When paper dust accumulates, the contact area of the peripheral surface with respect to the paper decreases, and the friction coefficient of the contact surface with respect to the paper decreases. As a result, a conveyance failure of the paper may occur.

In order to suppress a paper conveyance failure, a device is known in which irregularities are formed on the circumferential surface of a paper feed roller (patent documents 1 and 2). For example, patent document 1 describes a structure in which a plurality of ridges and grooves are formed parallel to the axial direction of a paper feed roller. Further, patent document 2 describes a technique in which embossings are formed on the circumferential surface of a paper feed roller.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-112833

Patent document 2: japanese patent laid-open publication No. 2000-296937

Disclosure of Invention

Problems to be solved by the invention

Conventional paper feed rollers have not been sufficient in terms of suppressing accumulation of paper dust for a long period of time from the initial stage of use and maintaining a good friction coefficient. In particular, among the paper sheets used in recent years, there are low-quality paper sheets, and paper dust is likely to be generated in the low-quality paper sheets, and a paper sheet conveyance failure is likely to occur in an early stage.

The invention provides a paper feed roller which can restrain poor paper transportation caused by paper powder accumulation for a long time.

Means for solving the problems

In order to solve the above problems, a paper feed roller according to the present invention includes a shaft body and an elastic body layer formed on an outer periphery of the shaft body, wherein a circumferential surface of the elastic body layer is provided with projections and recesses by projections, the projections are arranged in a direction different from an axial direction along the circumferential surface of the elastic body layer, a groove of a continuous recess is formed between a row of the projections in the direction different from the axial direction and a row of the projections parallel to the row, and a width of the groove is larger than a separation distance of the projections in the row of the projections.

Preferably, the convex portion is a hemispherical convex portion. Preferably, the convex portions are arranged along the circumferential surface of the elastomer layer in a direction different from the circumferential direction. In this case, it is preferable that the convex portions be spirally arranged along the peripheral surface of the elastic body layer. Preferably, the convex portions are arranged along the circumferential surface of the elastomer layer in a direction at an angle of ± 10 ° or less with respect to the circumferential direction. The convex portions may be arranged in the circumferential direction along the circumferential surface of the elastic body layer.

Preferably, the distance of separation of the projections in the row of projections is in the range of 0 to 0.6 mm. Preferably, the width of the groove is in the range of 0.01 to 2.0 mm. Preferably, the height of the projection is in the range of 0.05 to 0.5 mm. Preferably, the radius of curvature of the convex portion is in the range of 0.05 to 1.0 mm. Preferably, the pitch of the grooves is in the range of 0.1 to 2.0 mm.

The convex portion may be a spherical convex portion. Preferably, the upper bottom of the spherical convex portion is a polished surface. The upper bottom of the spherical convex part may be a flat surface. The upper bottom of the spherical convex portion may be a curved surface having a curvature radius larger than that of the spherical belt of the spherical convex portion. Preferably, the ratio (r1/r2) of the diameter r1 of the upper bottom of the spherical convex part to the diameter r2 of the lower bottom is in the range of 0.50 to 0.95. Preferably, an angle formed by a tangent plane of the ball belt of the spherical convex portion at an intersection point with the upper bottom of the spherical convex portion and the upper bottom of the spherical convex portion is in a range of 100 ° to 150 °. Preferably, the height of the spherical convex part is in the range of 0.02 to 0.40 mm.

Effects of the invention

According to the paper feed roller of the present invention, the rows of the convex portions arranged in the direction different from the axial direction along the peripheral surface of the elastic body layer and the rows of the convex portions parallel to the rows form the grooves of the continuous concave portions in the direction different from the axial direction along the peripheral surface of the elastic body layer, and the width of the grooves is larger than the separation distance of the convex portions in the rows of the convex portions arranged in the direction different from the axial direction, so that the conveyance failure of the paper due to the accumulation of paper dust can be suppressed for a long period of time. This is because, by making the width of the groove larger than the distance of separation of the convex portions in the row of convex portions arranged in the direction different from the axial direction, paper dust generated at the convex portions forming the contact surface with the paper sheet at the time of paper feeding easily escapes from the convex portions to the adjacent grooves, and further, since the groove is continuous in the direction different from the axial direction, the paper dust is easily discharged from the groove to the outside of the roller without staying in the groove as the roller rotates.

In this case, if the convex portion is hemispherical, the contact surface with the paper is a curved surface, so that generation of paper dust can be relatively suppressed, and the paper feeding performance is also excellent. Further, if the convex portions are arranged along the circumferential surface of the elastic body layer in a direction different from the circumferential direction, paper dust generated by the convex portions can be more easily caused to escape from the convex portions to the adjacent grooves than in the case of being arranged in the circumferential direction. This can further suppress a paper conveyance failure due to accumulation of paper dust. Further, if the convex portions are arranged along the circumferential surface of the elastic body layer in a direction at an angle within ± 10 ° with respect to the circumferential direction, paper dust generated by the convex portions is particularly likely to escape from the convex portions to the adjacent grooves. Further, even if the convex portions are arranged in the circumferential direction along the circumferential surface of the elastic body layer, paper dust generated by the convex portions can easily escape from the convex portions to the adjacent grooves.

Further, if the distance of separation of the projections in the row of projections is in the range of 0 to 0.6mm, paper dust is less likely to remain in the gaps in the row of projections, and paper dust is likely to move to the adjacent grooves and to be discharged into the grooves. Further, since the number of convex portions in the direction of the row of convex portions is increased, the contact area with the paper is increased, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed.

Further, if the width of the groove is in the range of 0.01 to 2.0mm, the paper dust moving to the groove is less likely to be jammed in the groove, and is easily discharged from the groove to the outside of the roller. Further, since the number of the convex portions in the axial direction is increased, the contact area with the paper is increased, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed.

Further, if the height of the projection is in the range of 0.05 to 0.5mm, the volume of the groove becomes large, and paper dust moving to the groove is less likely to be clogged in the groove, and is easily discharged from the groove to the outside of the roller. Further, since the size of the projection is appropriately suppressed to be small, the moving distance of the paper dust to the groove can be suppressed to be short, and the paper dust can be easily discharged to the groove.

Further, if the radius of curvature of the convex portion is in the range of 0.05 to 1.0mm, the contact area with the paper becomes large, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed. Further, since the size of the projection is appropriately suppressed to be small, the moving distance of the paper dust to the groove can be suppressed to be short, and the paper dust can be easily discharged to the groove.

Further, if the pitch of the grooves is in the range of 0.1 to 2.0mm, the width of the grooves becomes large, so that paper dust moving to the grooves is less likely to be jammed in the grooves, and is easily discharged from the grooves to the outside of the roller. Further, since the size of the projection is appropriately suppressed to be small, the moving distance of the paper dust to the groove can be suppressed to be short, and the paper dust can be easily discharged to the groove.

Further, if the convex portion is formed in a spherical table shape, the generation of paper dust is suppressed, and a paper conveyance failure can be suppressed for a long period of time. Further, if the upper bottom of the spherical convex portion is a polished surface, the generation of paper dust can be particularly suppressed. Further, when the ratio (r1/r2) of the diameter r1 of the upper bottom of the projection to the diameter r2 of the lower bottom is in the range of 0.50 to 0.95, the occurrence of paper dust can be suppressed particularly, and the conveyance failure of the paper can be suppressed for a long period of time. Further, if the angle formed by the tangent plane of the spherical zone of the convex portion at the intersection point with the upper bottom of the convex portion and the upper bottom of the convex portion is in the range of 100 ° to 150 °, the occurrence of paper dust can be particularly suppressed, and the conveyance failure of the paper can be suppressed for a long period of time.

Drawings

Fig. 1 is an external view schematically showing a paper feed roller according to an embodiment of the present invention.

Fig. 2 (a) is an enlarged schematic view of the circumferential surface of the paper feed roller shown in fig. 1, and fig. 2 (b) is a sectional view taken along line a-a thereof.

Fig. 3 (a) and (b) are enlarged schematic sectional views showing the convex portion of the paper feed roller, in which fig. 3 (a) is a view showing a half shape of the ball cut by a plane passing through the center of the ball, and fig. 3 (b) is a view showing a shape smaller than the half shape of the ball cut by a plane not passing through the center of the ball.

Fig. 4 is an external view schematically showing a paper feed roller according to another embodiment of the present invention.

Fig. 5 is an external view schematically showing a paper feed roller according to another embodiment of the present invention.

Fig. 6 shows an example of the cross-sectional shape of the projection, which is a spherical-truncated projection.

Fig. 7 shows an example of the cross-sectional shape of the convex portion, which is a spherical-table-shaped convex portion having a polished surface.

Detailed Description

The paper feed roller according to the present invention (hereinafter, may be simply referred to as a paper feed roller) will be described in detail. Fig. 1 is an external view schematically showing a paper feed roller according to an embodiment of the present invention. Fig. 2 (a) is an enlarged schematic view of the circumferential surface of the paper feed roller shown in fig. 1, and fig. 2 (b) is a sectional view taken along line a-a thereof.

The paper feed roller 10 according to one embodiment of the present invention includes a shaft 12 and an elastic body layer 14 formed on the outer periphery of the shaft 12. The elastic body layer 14 is a layer (outermost layer) exposed to the surface of the paper feed roller 10. The elastomer layer 14 is tubular (cylindrical).

A hemispherical convex portion 16 is provided on the peripheral surface of the elastomer layer 14. A concave portion lower than the convex portion 16 is formed between the convex portion 16 and the convex portion 16, and the convex portion 16 provides a concave-convex portion on the peripheral surface of the elastomer layer 14. The spherical shape means a substantially spherical shape, and may be a shape close to a spherical shape having a curved surface. The spherical shape includes, for example, a regular spherical shape and an elliptical spherical shape. The hemispherical shape also includes a shape of a half of a sphere cut by a plane passing through the center of the sphere, a shape larger than the half of the sphere cut by a plane not passing through the center of the sphere, and a shape smaller than the half of the sphere.

The convex portions 16 are arranged along the circumferential surface of the elastomer layer 14 in a direction different from the axial direction X. Specifically, the convex portions 16 are aligned along the circumferential surface of the elastomer layer 14 in a direction at a predetermined angle θ with respect to the circumferential direction Y. The convex portions 16 are arranged spirally along the circumferential surface of the elastic body layer 14. Further, the convex portions 16 are also arranged in the axial direction X along the circumferential surface of the elastomer layer 14, but the convex portions 16 may not be arranged in the axial direction X.

In the rows of the convex portions 16 in the direction different from the axial direction X, the convex portions 16 in the rows are separated from the convex portions 16 at a predetermined interval a. A groove 18 of a continuous concave portion is formed between a row of the convex portions 16 in a direction different from the axial direction X and a row of the convex portions 16 parallel to the row. The width b of the groove 18 is greater than the protrusion separation distance a. The width b of the groove 18 is a distance separating the row of the projections 16 in a direction different from the axial direction X and the row of the projections 16 parallel to the row in the axial direction X.

According to the sheet feed roller 10, the rows of the convex portions 16 aligned in the direction different from the axial direction X along the peripheral surface of the elastic layer 14 and the rows of the convex portions 16 parallel to the rows form the grooves 18 of the concave portions continuous in the direction different from the axial direction X along the peripheral surface of the elastic layer 14, and the width of the grooves 18 is larger than the convex portion separation distance a in the rows of the convex portions 16 aligned in the direction different from the axial direction, so that the conveyance failure of the sheet due to the accumulation of paper dust can be suppressed for a long period of time. This is because, by making the width of the groove 18 larger than the protrusion separation distance a in the row of the protrusions 16 aligned in the direction different from the axial direction X, paper dust generated at the protrusion 16 which becomes a contact surface with the paper sheet at the time of paper feeding easily escapes from the protrusion 16 to the adjacent groove 18, and since the groove 18 is a groove continuous in the direction different from the axial direction, the paper dust is easily discharged from the groove 18 to the outside of the roller without staying in the groove 18 with the rotation of the roller. In the paper feed roller 10, the grooves 18 of the continuous concave portion are formed in the direction of the predetermined angle θ with respect to the circumferential direction Y, and therefore paper dust generated at the convex portion 16 is more likely to escape from the convex portion 16 to the adjacent groove 18. Further, since the convex portion 16 is hemispherical and the contact surface with the paper is a curved surface, the generation of paper dust can be relatively suppressed and the paper feeding performance is excellent.

In the rows of the convex portions 16 in the direction different from the axial direction X, the angle θ is preferably within ± 10 ° with respect to the circumferential direction Y. That is, the convex portions 16 are preferably arranged along the circumferential surface of the elastomer layer 14 in a direction at an angle within Y ± 10 ° with respect to the circumferential direction. As described above, when the grooves 18 of the continuous concave portion are formed in the direction of the predetermined angle θ with respect to the circumferential direction Y, the paper dust generated at the convex portion 16 can be more easily caused to escape from the convex portion 16 to the adjacent groove 18. On the other hand, if the angle θ is too large, paper dust moving to the groove 18 is likely to accumulate at the corner of the groove 18. Therefore, the angle θ is preferably within ± 10 ° with respect to the circumferential direction Y from the viewpoint of easy discharge of paper dust from the groove 18 to the outside of the roller.

The protrusion separation distance a is preferably in the range of 0 to 0.6 mm. If the projection separation distance a is 0.6mm or less, paper dust is less likely to accumulate in the gaps in the rows of the projections 16, and the paper dust is more likely to move to the adjacent grooves 18, thereby facilitating the discharge of the paper dust to the grooves 18. Further, since the number of the convex portions 16 in the row direction of the convex portions 16 is increased, the contact area with the paper is increased, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed. From this viewpoint, the projection separation distance a is more preferably 0.5mm or less, and still more preferably 0.4mm or less.

The width b of the groove 18 is preferably in the range of 0.01 to 2.0 mm. If the width b of the groove 18 is 0.01mm or more, the paper dust moved to the groove 18 is less likely to be jammed in the groove 18, and is easily discharged from the groove 18 to the outside of the roller. From this viewpoint, the width b of the groove 18 is more preferably 0.05mm or more, and still more preferably 0.1mm or more. When the width b of the groove 18 is 2.0mm or less, the number of the convex portions 16 in the axial direction X increases, so that the contact area with the paper increases, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed. From this viewpoint, the width b of the groove 18 is more preferably 1.8mm or less, and still more preferably 1.5mm or less.

The height h of the projection 16 is preferably in the range of 0.05 to 0.5 mm. When the height h of the projection 16 is 0.05mm or more, the volume of the groove 18 becomes large, and the paper dust moved to the groove 18 is less likely to be jammed in the groove 18 and is easily discharged from the groove 18 to the outside of the roller. From this viewpoint, the height h of the projection 16 is more preferably 0.1mm or more. Further, if the height h of the projection 16 is 0.5mm or less, the size r' of the projection 16 is appropriately suppressed to be small, so that the moving distance of the paper dust to the groove 18 can be suppressed to be short, and the paper dust can be easily discharged to the groove 18. From this viewpoint, the height h of the projection 16 is more preferably 0.3mm or less.

The radius r of curvature of the convex portion 16 is preferably in the range of 0.05 to 1.0 mm. When the radius of curvature of the convex portion 16 is 0.05mm or more, the contact area with the paper becomes large, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed. From this viewpoint, the radius of curvature r of the convex portion 16 is more preferably 0.10mm or more. Further, if the radius r of curvature of the convex portion 16 is 1.0mm or less, the size r' of the convex portion 16 is appropriately suppressed to be small, so that the moving distance of the paper dust to the groove 18 can be suppressed to be short, and the paper dust can be easily discharged to the groove 18. From this viewpoint, the radius of curvature r of the convex portion 16 is more preferably 0.8mm or less.

The size r' of the projections 16 is represented by the maximum diameter of the projections 16. The size r' of the convex portion 16 is determined by the height h of the convex portion 16 and the radius of curvature r of the convex portion 16. In order to set the size r' of the convex portion 16 to a predetermined size, the height h of the convex portion 16 and the curvature radius r of the convex portion 16 may be adjusted. The size r' of the projection 16 is preferably in the range of 0.10 to 1.73 mm. When the size r' of the projection 16 is 0.10mm or more, the contact area with the paper becomes large, the load on the paper is suppressed to be small, and the generation of paper dust is easily suppressed. From this viewpoint, the size r' of the projection 16 is more preferably 0.20mm or more. When the size r' of the projection 16 is 1.73mm or less, the moving distance of the paper dust to the groove 18 is suppressed to be short, and the paper dust is easily discharged to the groove 18. From this viewpoint, the size r' of the convex portion 16 is more preferably 1.30mm or less.

Regarding the relationship between the height h of the convex portion 16 and the radius of curvature r, if h is r, the convex portion 16 has a shape of half a sphere cut by a plane passing through the center of the sphere as shown in fig. 3 (a). On the other hand, if h < r, the convex portion 16 has a shape smaller than half of the sphere as shown in fig. 3 (b). In the case of the shape shown in fig. 3 (b), since the angle of the tangent line l is gentle, the paper dust easily moves from the projection 16 to the groove 18, and the paper dust is easily discharged to the groove 18. From this viewpoint, in the relationship between the height h of the convex portion 16 and the radius of curvature r, h < r is preferable. In addition, h < (1/2) × r is particularly preferable.

The pitch p of the grooves 18 is determined by the size r' of the convex portions 16 (the radius of curvature r of the convex portions 16 and the height h of the convex portions 16) and the width b of the grooves 18. The pitch p of the grooves 18 may be determined as appropriate. The pitch p of the grooves 18 is preferably in the range of 0.1 to 2.0 mm. When the pitch p of the grooves 18 is 0.1mm or more, the width of the grooves 18 increases, and therefore paper dust moving to the grooves 18 is less likely to be jammed in the grooves 18 and is easily discharged from the grooves 18 to the outside of the roller. From this viewpoint, the pitch p of the grooves 18 is more preferably 0.3mm or more. When the pitch p of the grooves 18 is 2.0mm or less, the size r' of the projection 16 is appropriately suppressed to be small, so that the moving distance of the paper dust to the grooves 18 can be suppressed to be short, and the paper dust can be easily discharged to the grooves 18. From this viewpoint, the pitch p of the grooves 18 is more preferably 1.8mm or less.

The arrangement angle θ of the convex portions 16, the convex portion separation distance a, the width b of the groove 18, the height h of the convex portions 16, the radius of curvature r of the convex portions 16, the size r' of the convex portions 16, and the pitch p of the groove 18 can be obtained by analyzing surface photographs and axial sectional photographs of the elastomer layer 14.

The paper feed roller according to the present invention is not limited to the above embodiment. For example, in the above embodiment, the hemispherical convex portions 16 are arranged spirally along the circumferential surface of the elastomer layer 14 in the direction of the predetermined angle θ with respect to the circumferential direction Y, but may be arranged not spirally but in a circumferential row in a direction of the predetermined angle θ with respect to the circumferential direction Y along the circumferential surface of the elastomer layer 14.

For example, in the above embodiment, the convex portion 16 is formed in a hemispherical shape, but may be formed in a shape with a lower portion expanded as long as it has a curved surface.

The paper feed roller according to the present invention may be configured as the paper feed roller 20 shown in fig. 4, for example. The paper feed roller 20 shown in fig. 4 has a difference in arrangement of the convex portions 16 compared to the paper feed roller 10 shown in fig. 1. Otherwise, the same as the sheet feeding roller 10 shown in fig. 1 is applied, and the description thereof is omitted.

In the paper feed roller 20 shown in fig. 4, the convex portions 16 are aligned along the circumferential surface of the elastic body layer 14 in a direction different from the axial direction X. Specifically, the protrusions 16 are arranged in the circumferential direction Y along the circumferential surface of the elastomer layer 14. Further, the convex portions 16 are also arranged in the axial direction X along the circumferential surface of the elastomer layer 14, but the convex portions 16 may not be arranged in the axial direction X.

In the rows of the convex portions 16 in the circumferential direction Y, the convex portions 16 in the rows are separated from the convex portions 16 at predetermined intervals. A continuous concave groove 18 is formed between the row of the convex portions 16 in the circumferential direction Y and the row of the convex portions 16 parallel to the row. The width of the groove 18 is greater than the separation distance of the projections 16. The width of the groove 18 is a distance separating the row of the projections 16 in the circumferential direction Y and the row of the projections 16 parallel to the row in the axial direction X.

According to the paper feed roller 20, the rows of the convex portions 16 arranged in the circumferential direction Y along the circumferential surface of the elastic layer 14 and the rows of the convex portions 16 parallel to the rows form the grooves 18 having continuous concave portions in the circumferential direction Y along the circumferential surface of the elastic layer 14, and the width of the grooves 18 is larger than the convex portion separation distance in the rows of the convex portions 16 arranged in the circumferential direction, so that a paper conveyance failure due to accumulation of paper dust can be suppressed for a long period of time. This is because, by making the width of the groove 18 larger than the protrusion separation distance in the row of the protrusions 16 arranged in the circumferential direction Y, paper dust generated at the protrusions 16 which become the contact surfaces with the paper sheet at the time of paper feeding easily escapes from the protrusions 16 to the adjacent grooves 18, and since the groove 18 is a groove continuous in the circumferential direction, the paper dust is easily discharged from the groove 18 to the outside of the roller without staying in the groove 18 as the roller rotates.

In the paper feed roller 20 shown in fig. 4, the projection separation distance, the width of the groove 18, the height of the projection 16, the curvature radius r of the projection 16, and the pitch p of the groove 18 may be set similarly to the projection separation distance a, the width b of the groove 18, the height h of the projection 16, and the pitch p of the groove 18 of the paper feed roller 10 shown in fig. 1.

In the above embodiment, the convex portion 16 is formed in a hemispherical shape, but the convex portion 16 may be formed in a spherical table shape. Fig. 5 shows a paper feed roller according to another embodiment of the present invention. Fig. 6 and 7 show examples of the cross-sectional shape of the spherical convex portion. The paper feed roller 30 shown in fig. 5 has a difference in shape of the convex portion 16 from the paper feed roller 10 shown in fig. 1. Otherwise, the same as the sheet feeding roller 10 shown in fig. 1 is applied, and the description thereof is omitted.

As shown in fig. 6, the convex portion 16 is a spherical-truncated convex portion. When the spherical surface intersects two parallel planes, the part of the spherical surface clamped by the two planes is a ball belt, and the solid body enclosed by the ball belt and the two planes is a ball table. That is, the spherical convex portion is a convex portion 16 formed of a solid surrounded by the ball belt 16a and two planes (an upper bottom 16b and a lower bottom 16 c). The upper bottom 16b is a surface exposed to the outside and serves as a contact surface with the paper. The lower base 16c is a surface integrated with the peripheral surface of the elastomer layer 14. The spherical surface is a substantially spherical surface, and may be a spherical surface having a shape close to a sphere having a curved surface. The spherical shape includes, for example, a regular spherical shape and an elliptical spherical shape. One of the two planes of the table may be a plane passing through the center of the ball, or both of the two planes of the table may be planes not passing through the center of the ball. The two flat surfaces of the table may be any surfaces close to a flat surface, and may be curved surfaces having a larger curvature radius than the ball belt, for example. That is, the upper bottom 16b of the truncated spherical convex portion 16 may be a flat surface or a curved surface having a larger curvature radius than the spherical belt. As shown in fig. 7, the upper bottom 16b of the convex portion 16 may be a polished surface k. The polishing surface k can be formed by polishing the upper bottom 16b of the convex portion 16.

According to such a paper feed roller 30, since the convex portion 16 provided on the peripheral surface of the elastic body layer 14 is a spherical convex portion, it is possible to suppress the generation of paper dust and suppress a paper conveyance failure for a long period of time, because the spherical belt 16a of the convex portion 16 is a curved surface that is convex upward, and the angle α formed by the tangent plane l of the spherical belt 16a of the convex portion 16 at the intersection point 16d that intersects with the upper bottom 16b of the convex portion 16 and the upper bottom 16b of the convex portion 16 is an obtuse angle and is relatively gentle, the paper surface does not easily hit the shoulder s that is the portion where the upper bottom 16b of the convex portion 16 intersects with the spherical belt 16a, thereby suppressing the generation amount of paper dust, and further, since the convex portion 16 has the upper bottom 16b that has a curved surface with a larger curvature radius than the plane or the spherical belt 16a, the contact area between the tip of the convex portion 16 and the paper is increased, stress is dispersed, and the pressing force against the paper is suppressed to be low, thereby suppressing the generation amount of paper dust generation, and particularly suppressing the generation of paper dust generation if.

The truncated spherical projection 16 preferably has a diameter of the lower base 16c larger than that of the upper base 16b, and the ratio (r1/r2) of the diameter r1 of the upper base 16b to the diameter r2 of the lower base 16c is preferably in the range of 0.50 to 0.95. from the viewpoint of r1/r2 being 0.50 or more, the area of the upper base 16b in contact with the paper becomes large, the stress dispersion is suppressed, the pressing force against the paper is suppressed low, and the amount of paper dust generation is easily suppressed small, from which viewpoint r1/r2 is more preferably 0.55 or more, and further preferably 0.60 or more, and from the viewpoint of r1/r2 being 0.95 or less, the angle α formed by the tangent plane l of the spherical belt 16a at the intersection 16d where the spherical belt 16a and the upper base 16b intersect is large, and the paper surface is less likely to encounter the portion s where the spherical belt 16a and the upper base 16b intersect, and therefore the amount of paper dust generation is preferably 0.90 or less from the viewpoint of r 3685 or less.

The angle α formed by the tangent plane l of the ball belt 16a of the convex portion 16 at the intersection point 16d intersecting the upper bottom 16b of the convex portion 16 and the upper bottom 16b of the convex portion 16 is preferably in the range of 100 ° to 150 °, when the formed angle α is 100 ° or more, the paper surface does not easily come into contact with the shoulder s, which is the portion where the upper bottom 16b of the convex portion 16 and the ball belt 16a intersect, and therefore the amount of paper dust generated is easily suppressed to be small, from this viewpoint, the formed angle α is more preferably 110 ° or more, and still more preferably 120 ° or more, and when the formed angle α is 150 ° or less, the area of the upper bottom 16b contacting the paper is increased, the stress is dispersed, the pressing force against the paper is suppressed to be low, and the amount of paper dust generated is easily suppressed to be small, from this viewpoint, the formed angle α is more preferably 145 ° or less, and more preferably 140 ° or less.

The height h of the projection 16 is preferably in the range of 0.02 to 0.40 mm. If the height h of the projection 16 is 0.02mm or more, the volume of the recess between the projection 16 and the projection 16 becomes large, and the generated paper dust is less likely to clog the recess. From this viewpoint, the height h of the projection 16 is more preferably 0.05mm or more. When the height h of the projection 16 is 0.40mm or less, the diameter r2 of the bottom 16c of the projection 16 is appropriately suppressed to be small, so that the dispersibility of the projection 16 is improved, and the effect of pressure dispersion on the paper is improved. This makes it easy to suppress the generation of paper dust. From this viewpoint, the height h of the projection 16 is more preferably 0.30mm or less.

The diameter r1 of the upper bottom 16b of the projection 16 is preferably in the range of 0.095 to 0.50 mm. When the diameter r1 of the upper bottom 16b is 0.095mm or more, the area of the upper bottom 16b in contact with the paper is large, the stress is dispersed, the pressing force against the paper is suppressed low, and the generation amount of paper dust is easily suppressed low. From this viewpoint, the diameter r1 of the upper bottom 16b is more preferably 0.10mm or more, and still more preferably 0.15mm or more. When the diameter r1 of the upper bottom 16b is 0.50mm or less, the diameter r2 of the lower bottom 16c of the convex portion 16 is appropriately suppressed to be small, so that the dispersibility of the convex portion 16 is improved, and the effect of pressure dispersion on the paper is improved. This makes it easy to suppress the generation of paper dust. From this viewpoint, the diameter r1 of the upper bottom 16b is more preferably 0.40mm or less.

The diameter r2 of the bottom 16c of the projection 16 is preferably in the range of 0.10 to 1.00 mm. If the diameter r2 of the lower base 16c is 0.10mm or more, the area of the upper base 16b that is in contact with the paper sheet becomes large, the stress is dispersed, the pressing force against the paper sheet is suppressed to be low, and the generation amount of paper dust is easily suppressed to be small. From this viewpoint, the diameter r2 of the lower base 16c is more preferably 0.20mm or more. When the diameter r2 of the bottom base 16c is 1.00mm or less, the diameter r2 of the bottom base 16c of the convex portion 16 is suppressed to be appropriately small, so that the dispersibility of the convex portion 16 is improved, and the effect of pressure dispersion on the paper is improved. This makes it easy to suppress the generation of paper dust. From this viewpoint, the diameter r2 of the lower base 16c is more preferably 0.80mm or less, and still more preferably 0.60mm or less.

The radius of curvature SR of the spherical belt 16a is preferably in the range of 0.05 to 0.50 mm. When the curvature radius SR is 0.05mm or more, the curved surface of the ball belt 16a is relatively gentle, the area of the upper bottom 16b in contact with the paper tends to increase, the stress is dispersed, the pressing force against the paper is suppressed to be low, and the amount of paper dust generated tends to be suppressed to be small. From this viewpoint, the curvature radius SR is more preferably 0.10mm or more. When the radius of curvature SR is 0.50mm or less, the diameter r2 of the bottom 16c of the convex portion 16 is appropriately suppressed to be small, so that the dispersibility of the convex portion 16 is improved, and the effect of pressure dispersion on the paper is improved. This makes it easy to suppress the generation of paper dust. From this viewpoint, the curvature radius SR is more preferably 0.40mm or less.

The diameter r1 of the upper bottom 16b of the convex portion 16, the diameter r2 of the lower bottom 16c, the radius SR of curvature of the ball band 16a, the height h, the angle α formed, and the like can be obtained by analyzing surface photographs and cross-sectional photographs of the elastomer layer 14.

In the paper feed roller 30 in which the convex portions 16 are formed in a spherical table shape, the convex portions 16 are arranged spirally along the circumferential surface of the elastic layer 14 in a direction at a predetermined angle θ with respect to the circumferential direction Y, as in the paper feed roller 10, but may be arranged not spirally but in a circumferential row in a direction at a predetermined angle θ with respect to the circumferential direction Y along the circumferential surface of the elastic layer 14.

Further, in the paper feed roller 30 in which the convex portions 16 are formed into a spherical table shape, the convex portions 16 are spirally arranged along the circumferential surface of the elastic body layer 14 in the direction of the predetermined angle θ with respect to the circumferential direction Y, but as in the paper feed roller 20 shown in fig. 4, in the paper feed roller in which the convex portions 16 are formed into a spherical table shape, the convex portions 16 may be arranged along the circumferential surface of the elastic body layer 14 in the circumferential direction Y. Further, the convex portions 16 are also arranged in the axial direction X along the circumferential surface of the elastomer layer 14, but the convex portions 16 may not be arranged in the axial direction X.

In the paper feed roller in which the convex portion 16 is formed in a spherical shape, the angle θ, the convex portion separation distance a, the width b of the groove 18, and the pitch p of the groove 18 may be set similarly to the angle θ, the convex portion separation distance, the width of the groove 18, the height of the convex portion 16, the pitch of the groove 18, and the like of the paper feed roller in which the convex portion 16 is formed in a hemispherical shape.

Next, a material structure of the paper feed roller according to the present invention will be described.

As the shaft body 12, a metal core made of a solid body made of metal, a cylindrical body made of metal with a hollow portion hollowed out, or the like is used. Examples of the material include stainless steel, aluminum, and a material obtained by plating iron. Further, an adhesive, a primer, or the like may be applied to the shaft body 12 as necessary, and the adhesive, the primer, or the like may be electrically conductive as necessary.

The elastomer layer 14 is formed of an elastic material such as a crosslinked rubber. The material is not particularly limited as long as it is a rubber-like elastic material. For example, a known rubber material such as urethane rubber, chlorohydrin rubber, and silicone rubber can be used.

The elastomer layer 14 preferably has electrical conductivity or electrical conductivity. Specifically, the volume resistivity of the elastomer layer 14 is preferably 10²～10¹⁰Ω·cm、10³～10⁹Ω·cm、10⁴～10⁸Range of Ω · cm. When the elastic layer 14 has conductivity or semiconductivity, the residual charge on the surface of the elastic layer 14 is easily suppressed to be low, and the adhesion of paper powder is easily suppressed.

From the viewpoint of lowering the resistance, the elastomer layer 14 may beTo contain a conductive agent. Examples of the conductive agent include an electron conductive agent and an ion conductive agent. Examples of the electron conductive agent include carbon black, graphite, and c-TiO₂、c-ZnO、c-SnO₂(c-represents conductivity), and the like. Examples of the ion conductive agent include quaternary ammonium salts, borates, and surfactants.

The elastomer layer 14 may be added with various additives as needed. Examples of the additives include lubricants, vulcanization accelerators, antioxidants, light stabilizers, viscosity modifiers, processing aids, flame retardants, plasticizers, fillers, dispersants, defoaming agents, pigments, and mold release agents.

The thickness of the elastomer layer 14 is not particularly limited, and may be appropriately set within a range of 0.1 to 10 mm.

The elastomer layer 14 can be formed by molding or the like using a rubber composition with a mold. For example, the elastic body layer 14 can be formed on the outer periphery of the shaft body 12 by disposing the shaft body 12 coaxially with the hollow portion of the roller-forming mold, injecting an uncrosslinked rubber composition, heating and curing (crosslinking) the composition, and then releasing the composition from the mold. As the forming mold, a mold having a concave portion formed on its inner peripheral surface in a shape corresponding to the convex portion 16 may be used. The convex portion 16 of the elastomer layer 14 can be formed by, for example, mold transfer using a molding die.

Examples

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples.

Examples 1 to 18 and comparative examples 1 to 4

Using a cylindrical mold having a predetermined concave portion on the inner peripheral surface, and forming a core material (C)

SUS 304) to form an elastomer layer (thickness 3mm) of the urethane rubber composition. Thus, a paper feed roller having the surface shape shown in fig. 4 or fig. 1 was obtained. That is, the convex and concave portions are provided on the peripheral surface of the elastomer layer by the hemispherical convex portions. In example 1 and comparative example 1, as shown in fig. 4, hemispherical protrusions were surrounded along the peripheral surface of the elastomer layerArranged in a pattern. In other examples and comparative examples, as shown in fig. 1, hemispherical protrusions were arranged spirally along the circumferential surface of the elastomer layer. Further, a continuous groove of concave portions is formed along the peripheral surface of the elastomer layer by the rows of convex portions and the rows of convex portions parallel to the rows. In each paper feed roller, the dimensions (protrusion separation distance a, groove width b, protrusion height h, protrusion radius of curvature r, and protrusion arrangement angle θ) shown in fig. 2 derived from the hemispherical protrusions are set as shown in tables 1 and 2.

The durability was evaluated by using the manufactured paper feed roller. The protrusion separation distance a, the groove width b, the height h of the protrusion, the radius of curvature r of the protrusion, and the arrangement angle θ of the protrusions are shown in tables 1 to 2.

(evaluation of durability)

The paper was passed through 10 ten thousand sheets of commercially available PPC paper, and the number of occurrences of paper jam due to paper dust was measured, "◎" in the case of no occurrence of paper jam, "○" in the case of paper jam occurrence number of 1 to 3 times, "△" in the case of paper jam occurrence number of 4 to 9 times, and "x" in the case of paper jam occurrence number of 10 or more.

TABLE 1

TABLE 2

According to the comparative example, the width b of the groove was smaller than the convex portion separation distance a in the row of convex portions, and the number of occurrences of paper jam caused by paper dust was as many as 10 or more, and durability was not satisfied. In contrast, according to the embodiment, the width b of the groove is larger than the protrusion separation distance a in the row of the protrusions, and the number of times of occurrence of paper jam due to paper dust is as small as 9 or less, thereby satisfying durability.

It is also understood that in the embodiment, if the angle θ is ± 10 ° or less, the number of times of occurrence of the jam can be further suppressed. Further, it is found that the number of times of occurrence of the jam can be suppressed more than the case where the angle θ is 0 ° and 5 °. It is also found that the number of occurrences of paper jams can be further suppressed when the protrusion separation distance a is 0.6mm or less, the groove width b is 2.0mm or less and 1.5mm or less, and the height h of the protrusions is 0.05 to 0.5 mm.

(example 19)

A paper feed roller was obtained in the same manner as in example 2, except that the spherical convex portions were replaced with the spherical convex portions shown in fig. 7. The upper bottom of the spherical convex part is composed of a grinding surface. The spherical protrusions are spirally arranged along the peripheral surface of the elastomer layer. Further, a continuous groove of concave portions is formed along the peripheral surface of the elastomer layer by the rows of convex portions and the rows of convex portions parallel to the rows. The dimensions are as follows.

Projection separation distance a: 0.3mm, width b of groove: 1.0mm, arrangement angle θ of convex portions: 5 degree

(example 20)

A paper feed roller was obtained in the same manner as in example 2, except that the spherical convex portions were replaced with the spherical convex portions shown in fig. 6. The upper bottom of the spherical convex part is formed by a plane. The spherical protrusions are spirally arranged along the peripheral surface of the elastomer layer. Further, a continuous groove of concave portions is formed along the peripheral surface of the elastomer layer by the rows of convex portions and the rows of convex portions parallel to the rows. The dimensions are as follows.

In examples 19 to 20, the amount of paper dust generated and the durability were measured using the manufactured paper feed roller. The results are shown in table 3 together with the structure of the convex portion.

(amount of paper dust produced)

The paper dust generation amount of each paper feed roller was represented by a relative ratio when the paper dust generation amount of example 1 was 1, a ratio of "◎" when the ratio was less than 1.0, a ratio of "○" when the ratio was 1.0 or more and less than 1.2, a ratio of "△" when the ratio was 1.2 or more and less than 2.0, and a ratio of "x" when the ratio was 2.0 or more.

(evaluation of durability)

As described above.

TABLE 3

As is clear from examples 19 to 20, the convex portions formed on the peripheral surface of the elastomer layer were formed in a spherical table shape, whereby generation of paper dust was suppressed, and durability was improved. Further, according to example 19, it is understood that the generation of paper dust can be suppressed in the case where the polishing surface is provided on the upper bottom of the spherical convex portion.

While the embodiments and examples of the present invention have been described above, the present invention is not limited to the embodiments and examples described above, and various modifications can be made without departing from the scope of the present invention.

Claims

1. A paper feed roller is characterized in that,

the paper feed roller comprises a shaft body and an elastic body layer formed on the periphery of the shaft body,

the peripheral surface of the elastomer layer is provided with projections and recesses by projections,

the convex portions are arranged along the circumferential surface of the elastomer layer in a direction different from the axial direction, and a groove of a continuous concave portion is formed between a row of convex portions in the direction different from the axial direction and a row of convex portions parallel to the row,

the width of the groove is larger than the protrusion separation distance in the row of the protrusions.

2. The paper feeding roller as claimed in claim 1, wherein the convex portion is a hemispherical convex portion.

3. The paper feeding roller according to claim 1 or 2, wherein the convex portions are aligned in a direction different from a circumferential direction along a circumferential surface of the elastic body layer.

4. The paper feeding roller as claimed in claim 3, wherein the convex portions are arranged spirally along the peripheral surface of the elastic body layer.

5. The paper feeding roller according to claim 3 or 4, wherein the convex portions are aligned along the circumferential surface of the elastic body layer in a direction at an angle within ± 10 ° with respect to the circumferential direction.

6. The paper feeding roller as claimed in claim 1 or 2, wherein the convex portions are arranged in a circumferential direction along a circumferential surface of the elastic body layer.

7. The paper feeding roller according to any one of claims 1 to 6, wherein a convex portion separation distance in the row of convex portions is in a range of 0 to 0.6 mm.

8. The paper feeding roller as claimed in any one of claims 1 to 7, wherein the width of the groove is in the range of 0.01 to 2.0 mm.

9. The paper feeding roller as claimed in any one of claims 1 to 8, wherein the height of the convex portion is in the range of 0.05 to 0.5 mm.

10. The paper feeding roller as claimed in any one of claims 2 to 9, wherein the radius of curvature of the convex portion is in the range of 0.05 to 1.0 mm.

11. The paper feeding roller as claimed in any one of claims 1 to 10, wherein the pitch of the grooves is in the range of 0.1 to 2.0 mm.

12. The paper feeding roller as claimed in claim 1, wherein the convex portion is a spherical-table-shaped convex portion.

13. The paper feeding roller as claimed in claim 12, wherein the upper bottom of the convex portion is a ground surface.

14. The paper feeding roller as claimed in claim 12, wherein the upper bottom of the convex portion is a flat surface.

15. The sheet feeding roller as claimed in claim 12, wherein the upper bottom of the convex portion is a curved surface having a radius of curvature larger than that of the spherical belt of the convex portion.

16. The sheet feeding roller as claimed in any one of claims 12 to 15, wherein a ratio (r1/r2) of a diameter r1 of an upper bottom of the convex portion to a diameter r2 of a lower bottom is in a range of 0.50 to 0.95.

17. The paper feeding roller as claimed in any one of claims 12 to 16, wherein an angle formed by a tangent plane of the spherical belt of the convex portion at an intersection point intersecting with an upper bottom of the convex portion and the upper bottom of the convex portion is in a range of 100 ° to 150 °.

18. The paper feeding roller as claimed in any one of claims 12 to 17, wherein the height of the convex portion is in the range of 0.02 to 0.40 mm.