JP5948193B2 - Paper feed roller - Google Patents

Description

  The present invention relates to a paper feed roller suitable for a paper feed roller (pickup roller, feed roller, retard roller) used in a paper feed device of a device such as a copying machine, a printer, and a facsimile, and a transport roller. More specifically, the present invention relates to a paper feed roller having a plurality of recesses on a cylindrical surface, and is particularly suitable for a paper feed roller.

  Some paper feed units of copiers, printers, facsimiles, and the like include a pickup roller, a feed roller, and a retard roller to feed paper one by one.

  For example, in the FRR type paper feeder as shown in FIG. 1, the pickup roller 1 feeds the paper 5 from the paper tray 6 to the separation unit, and the separation unit includes a torque limiter 4 provided in pressure contact with the feed roller 2. A double feed of the paper 5 is prevented by the provided retard roller 3.

  That is, when a paper feed command is issued, the pickup roller 1 and the feed roller 2 start to rotate. At that time, the retard roller 3 pressed against the feed roller 2 is also rotated together with the feed roller 2. The sheet 5 called from the tray 6 by the pickup roller 1 enters between the feed roller 2 and the retard roller 3, and is pressed and advanced by the feed roller 2 and the retard roller 3. At this time, the retard roller 3 is given a rotational force in the direction of returning the paper 5, but the paper is sandwiched between the feed roller 2 and rotated.

  When two sheets of paper are called by the pickup roller 1 and enter between the feed roller 2 and the retard roller 3, the retard roller 3 is given a predetermined torque in the direction of returning the paper 5, so that the paper 2 When the sheets enter between the feed roller 2 and the retard roller 3 together, the retard roller 3 rotates in the returning direction to return the paper 5 in contact with the retard roller 3, and only the uppermost paper in contact with the feed roller 2 advances. To do.

  Such a paper feed roller is generally made of EPDM or polyurethane. Moreover, when paper dust adheres to the surface of such a paper feed roller, the coefficient of friction decreases and the paper cannot be stably conveyed. Therefore, a paper feed roller is known in which a recess for allowing paper dust to fall is provided on the cylindrical surface of the paper feed roller. Such a paper feed roller is described in, for example, JP-A-9-183533 (Patent Document 1).

  The cylindrical portion 100 of the paper feed roller described in Patent Document 1 is provided with a pattern groove 102 that forms a diamond-shaped cylindrical surface 101 indicated by dots in the drawing by crossing each other as shown in FIG. It is characterized by that.

JP-A-9-183533

  The paper feed roller described in Patent Document 1 is configured as described above. However, since the area of the cylindrical surface 101 in contact with the paper is large, paper dust easily adheres to the cylindrical surface 101. When the number of sheets to be passed increases, the friction coefficient decreases due to the accumulation of paper powder, and the paper is conveyed. For this reason, there is a problem that sufficient frictional force cannot be obtained.

  The present invention has been made to solve the above-described problems, and it is difficult for paper dust to accumulate on the cylindrical surface, and even if an external force is applied, the amount of paper transport caused by deformation or collapse of the convex portion on the cylindrical surface is reduced. It is an object of the present invention to provide a paper feed roller that is less likely to be delayed or worn with respect to the rotation angle of the roller shaft, and that can stably transport paper even after long-term use.

  The paper feed roller according to the present invention has a large number of recesses on the cylindrical surface. The plurality of recesses are provided regularly arranged in the axial direction and circumferential direction of the paper feed roller so that the cylindrical surface interposed between the plurality of recesses forms a lattice pattern.

  Preferably, the cylindrical surface interposed between the adjacent recesses has a mountain-shaped ridge shape with the adjacent recesses as a skirt.

  Preferably, the depth of the recess is 0.1 mm or greater and 1.0 mm or less.

  Preferably, the recess has a bottom surface, and a recess is further provided in an inner region of the bottom surface.

  Preferably, the depth of the bottom surface of the recess is 0.1 mm or more and 1.0 mm or less, and the depth from the bottom surface of the recess further provided in the inner region of the bottom surface is 0.01 mm or more and 1.0 mm or less.

  Preferably, the axial length of the cylindrical surface interposed between adjacent recesses in the axial direction and the circumferential length of the cylindrical surface interposed between adjacent recesses in the circumferential direction are 0.2 mm. It is 1.0 mm or less.

  Preferably, the ratio S2 / S1 of the area (S2) of many recesses and the area (S1) of the cylinder surface interposed between the many recesses on the entire cylindrical surface is in the range of 0.5 to 5. It is.

  In the present invention, a large number of concave portions are provided on the cylindrical surface, and the large number of concave portions are arranged in the axial direction and the circumferential direction of the paper feed roller so that the cylindrical surface interposed between the numerous concave portions forms a lattice pattern. To be arranged regularly.

  As a result, paper dust is unlikely to accumulate on the cylindrical surface, and even if an external force is applied, the paper conveyance amount is unlikely to be delayed or worn with respect to the rotation angle of the roller shaft due to deformation or collapse of the convex portion on the cylindrical surface, and used for a long time. However, it is possible to provide a paper feed roller capable of stably transporting paper.

It is the schematic which shows the side surface of a paper feeder. 6 is a perspective view showing a part of a cylindrical portion 100 of a paper feed roller described in Patent Document 1. FIG. It is a perspective view which shows a part of cylindrical part 20 of the paper feed roller which concerns on 1st Embodiment of this invention. FIG. 4 is a IV-IV sectional view of a cylindrical portion 20 of the paper feed roller shown in FIG. 3. It is a perspective view which shows a part of cylindrical part 20 of the paper feed roller which concerns on 2nd Embodiment of this invention. FIG. 6 is a VI-VI sectional view of a cylindrical portion 20 of the paper feed roller shown in FIG. 5.

(1) First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the cylindrical portion 20 of the paper feed roller according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a perspective view showing a part of the cylindrical portion 20 of the paper feed roller according to this embodiment. The direction indicated by the arrow in the drawing is the direction in which the cylindrical portion 20 rotates, and the cylindrical portion. 20 circumferential directions. 4 is a cross-sectional view taken along the line IV-IV of the cylindrical portion 20 of the paper feed roller shown in FIG.

  Referring to FIG. 3, the cylindrical portion 20 of the paper feed roller is made of polyurethane and contacts the paper to be conveyed. The cylindrical surface 21 indicated by dots in the figure, and the inner diameter direction of the cylindrical portion 20 relative to the cylindrical surface 21 And a recess 22 having a large number of bottom surfaces. In addition, although the one part perspective view of the cylindrical part 20 was shown in FIG. 3, the cylindrical surface 21 and many recessed parts 22 are provided over the cylindrical part 20 whole with the same aspect.

  When paper dust adheres to the cylindrical surface 21, the friction coefficient of the cylindrical surface 21 decreases, and a sufficient frictional force for conveying the paper cannot be obtained. Therefore, in order to prevent paper dust from accumulating on the cylindrical surface 21, a large number of recesses 22 are provided as a space for the paper dust attached to the cylindrical surface 21 to fall. The plurality of recesses 22 are provided regularly arranged in the axial direction and the circumferential direction of the cylindrical portion 20 so that the cylindrical surface 21 interposed between the plurality of recesses 22 itself forms a lattice pattern.

  By doing so, the area of the cylindrical surface 21 can be reduced compared to the paper feed roller described in Patent Document 1, so paper dust is less likely to accumulate on the cylindrical surface 21 and the reduction in the friction coefficient is reduced. can do. That is, even in long-term use, the frictional force necessary for conveying the paper can be sufficiently obtained. Further, since the cylindrical surface 21 is continuous, the paper conveyance amount is delayed with respect to the rotation angle of the roller shaft due to the deformation / falling of the convex portion on the cylindrical surface, although the area of the convex portion on the cylindrical surface is relatively small. And wear is less likely to occur. The external force here is a force acting between the paper and the paper feed roller when the cylindrical surface of the paper feed roller comes into contact with the paper, as shown in FIG.

  That is, since the diamond-shaped cylindrical surface 101 provided in the paper feed roller described in Patent Document 1 is isolated, the delay or wear of the paper conveyance amount with respect to the rotation angle of the roller shaft due to deformation or collapse of the convex portion of the cylindrical surface is suppressed. Therefore, when the rigidity is increased, there is a problem that the contact area with the paper increases, and the adhesion of the paper powder and the decrease in the friction coefficient due to the adhesion tend to occur. If the contact area with the paper is reduced in order to suppress the adhesion of paper dust, the rigidity of the convex part will be reduced, and the paper conveyance amount will be delayed with respect to the rotation angle of the roller shaft due to the deformation or collapse of the convex part on the cylindrical surface. And there was a problem of wear.

  On the other hand, since the cylindrical surface 21 of the present application is continuous over the entire cylindrical portion 20, the cylindrical surface 21 has sufficient rigidity with respect to the external force described above and is not easily deformed. Furthermore, the cylindrical surface 21 of the present application has a sufficient rigidity against the above-described external force, so that the depth of the recess 22 can be increased. In other words, if the depth of the concave portion 22 is increased, the rigidity of the cylindrical portion 20 with respect to the above-described external force is lowered and easily deformed. However, since the cylindrical surface 21 of the present application has sufficient rigidity, The depth of the recess can be increased. Since the depth of the concave portion can be increased, a sufficient space for the paper powder to fall can be secured even after the paper is passed for a long time.

  Referring to FIG. 4, cylindrical surface 21 interposed between adjacent recesses 22 has a chevron shape having an adjacent recess 22 as a skirt. Specifically, the cross section is arcuate. By doing so, the paper dust adhering to the cylindrical surface 21 is likely to fall into the recess 22, so that the paper dust is less likely to accumulate on the cylindrical surface 21, and the reduction in the friction coefficient can be reduced.

  In addition, it is preferable that the depth A of the recessed part 22 is 0.1 mm or more and 1.0 mm or less. If this is smaller than 0.1 mm, it is not deep enough as a space where paper dust falls. On the other hand, if it is larger than 1.0 mm, the rigidity against the above-mentioned external force is not sufficient, deformation / falling easily occurs, and uneven wear is also likely to occur.

  In addition, the axial length of the cylindrical surface 21 interposed between the concave portions 22 adjacent in the axial direction and the circumferential length B of the cylindrical surface 21 interposed between the concave portions 22 adjacent in the circumferential direction are: It is preferable that they are 0.2 mm or more and 1.0 mm or less. This is because if it is smaller than 0.2 mm, it is difficult to secure a contact area with the paper for expressing the necessary frictional force, and the cylindrical surface 21 is likely to be unevenly worn. On the other hand, if it is larger than 1.0 mm, paper dust tends to accumulate on the cylindrical surface 21, the friction coefficient decreases, and the frictional force for conveying the paper cannot be obtained sufficiently.

(2) Second Embodiment Next, a cylindrical portion 20 of a paper feed roller according to a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. In the paper feed roller according to this embodiment, an inner concave portion 23 is further provided in a region inside the bottom surface of the concave portion 22 included in the paper feed roller according to the first embodiment. The paper feed roller according to this embodiment has the same shape as that of the paper feed roller according to the first embodiment except that the inner recess 23 is provided. Therefore, the same parts are denoted by the same reference numerals, and the same description is omitted.

  FIG. 5 is a perspective view showing a part of the cylindrical portion 20 of the paper feed roller according to this embodiment. 6 is a VI-VI cross-sectional view of the cylindrical portion 20 of the paper feed roller shown in FIG. Referring to FIG. 5, the cylindrical portion 20 of the paper feed roller according to this embodiment has a large number of concave portions 22 that are recessed in the inner diameter direction of the cylindrical portion 20 rather than the cylindrical surface 21. An inner recess 23 is further provided in the inner region of the bottom surface.

  That is, the cylindrical portion 20 of the paper feed roller according to this embodiment has a large number of recesses having a double bottom surface. As described above, the concave portion having the double bottom surface can secure the concave portion 23 in which the paper powder falls even after the convex portion which is the initial cylindrical surface 21 disappears due to abrasion by passing a large amount of paper. The number of paper durability can be increased.

  Referring to FIG. 6, the depth C of the bottom surface of the recess 22 according to this embodiment is preferably 0.1 mm or more and 1.0 mm or less, and the recess of the inner recess 23 provided on the bottom surface of the recess 22. The depth D from the bottom surface of 22 is preferably 0.01 mm or more and 1.0 mm or less. If the depth C of the bottom surface of the concave portion 22 is smaller than 0.1 mm, the space for paper dust to fall becomes too small, and if it is larger than 1.0 mm, a roller with a paper conveyance amount due to deformation or collapse of the convex portion of the cylindrical surface Delay and wear with respect to the rotation angle of the shaft are likely to occur.

  If the depth D from the bottom surface of the recess 22 is smaller than 0.01 mm, a large amount of paper passes, and after the depth C of the bottom surface of the recess 22 shown in FIG. It is difficult to secure the concave portion 23, and if it is larger than 1.0 mm, it affects the rigidity of the convex portion of the roller surface, and the paper conveyance amount due to deformation or collapse tends to be delayed or worn with respect to the rotation angle of the roller shaft. .

  The length in the axial direction of the cylindrical surface 21 interposed between the concave portions 22 adjacent in the axial direction and the length E in the circumferential direction of the cylindrical surface 21 interposed between the concave portions 22 adjacent in the circumferential direction are: The thickness is preferably 0.2 mm or more and 1.0 mm or less. This is because if it is smaller than 0.2 mm, it is difficult to secure a contact area with the paper for expressing a necessary friction coefficient, and the cylindrical surface 21 is likely to be unevenly worn. On the other hand, if it is larger than 1.0 mm, paper dust tends to accumulate on the cylindrical surface 21, the friction coefficient is lowered, and a frictional force for conveying the paper cannot be obtained sufficiently.

  In this embodiment, the ratio S4 / S3 of the area S4 surrounded by the outer contour line of the inner recess 23 to the area S3 surrounded by the outer contour line of the recess 22 is in the range of 0.1 to 0.9. Preferably there is. If this is smaller than 0.1, the effect of further providing the inner concave portion 23 inside the concave portion 22 is reduced. On the other hand, if it is larger than 0.9, the rigidity of the convex portion on the roller surface is affected, and the paper conveyance amount is likely to be delayed or worn with respect to the rotation angle of the roller shaft due to deformation or collapse of the convex portion on the cylindrical surface. .

  In addition, in this embodiment, although the cylindrical part 20 demonstrated the case where it had many recessed parts provided with a double bottom face, it is not restricted to this, You may provide a triple bottom face, and it is a quadruple or more recessed part. May be provided.

  In this embodiment, the outer contour line of the inner concave portion 23 has been described as having a rectangular shape. However, the present invention is not limited thereto, and may be a triangular shape or a polygonal shape that is a pentagon or more. There may be other shapes.

  In the first and second embodiments described above, the ratio S2 / of the area S2 of the many concave portions 22 and the area S1 of the cylindrical surface 21 interposed between the many concave portions 22 in the entire cylindrical portion 20. S1 is preferably in the range of 0.5 to 5.

  In addition, the area S1 of the cylindrical surface 21 interposed between the many concave portions 22 and the area S2 of the numerous concave portions 22 in the entire cylindrical portion 20 can be obtained by measuring as follows. Ink is adhered to the cylindrical surface of the roller and pressed against the paper for 5 seconds at a load of 250 gf. Here, attention is paid to a region (for example, 5 mm × 5 mm square) inside the outer frame of the ink adhesion portion transferred to the paper. Let S be the area of this focused region. Within that region, the area of the portion where the ink has been transferred to the paper is measured by a prescale pressure image analysis system FPD-9270 manufactured by Fuji Film, and S1 is obtained. Next, S2 is obtained by calculating S-S1.

  When the area ratio S2 / S1 is smaller than 0.5, paper dust is easily accumulated, the friction coefficient is lowered, and a frictional force for conveying the paper cannot be obtained sufficiently. On the other hand, if the area ratio S2 / S1 is larger than 5, it is difficult to secure a contact area with the paper for expressing a necessary friction coefficient.

  The cylindrical portion 20 of the paper feed roller according to the first and second embodiments described above is a paper feed roller (pickup roller, feed roller, A retard roller), a transport roller, and the like, and particularly suitable for a paper feed roller.

  In the first and second embodiments described above, the multiple recesses 22 are arranged in the axial direction of the paper feed roller so that the cylindrical surface 21 interposed between the multiple recesses 22 forms a lattice pattern. Although the case where they are arranged regularly in the circumferential direction has been described, the present invention is not limited to this, and the numerous recesses 22 are regularly arranged in the axial direction and circumferential direction of the paper feed roller so as to have a honeycomb structure. May be provided. Further, the multiple recesses 22 may be provided regularly arranged in the axial direction and the circumferential direction of the paper feed roller so that the cylindrical surface 21 interposed between the multiple recesses 22 forms another shape. .

  In the first and second embodiments described above, the cylindrical surface 21 interposed between the adjacent recesses 22 has been described as having a chevron shape with the adjacent recesses 22 as hems. The shape is not limited to this, and may be flat or other shapes.

  In the first and second embodiments described above, the concave portion 22 has been described as having a flat bottom surface. However, the present invention is not limited to this, and the concave portion 22 may have a concave and convex bottom surface, or other shapes. May have a bottom surface.

  In the first and second embodiments described above, the paper feed roller is described as being formed from polyurethane. However, the present invention is not limited to this, and the paper feed roller may be formed from EPDM or other synthetic rubber. You may form with substances other than a synthetic rubber.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  According to the present invention, the paper feed roller is unlikely to accumulate paper dust on the cylindrical surface, and even when an external force is applied, the paper feed amount is delayed with respect to the rotation angle of the roller shaft due to deformation or falling of the convex portion on the cylindrical surface. Since it does not easily wear and can stably transport paper even after long-term use, it is advantageously used as a paper feed roller.

  DESCRIPTION OF SYMBOLS 1 Pickup roller, 2 Feed roller, 3 Retard roller, 4 Torque limiter, 5 Paper, 6 Paper tray, 20 Cylindrical part, 21 Cylindrical surface, 22 Recessed part, 23 Inner recessed part, 100 Cylindrical part of patent document 1, 101 patent The cylindrical surface described in Document 1 and the pattern groove described in Patent Document 1.

Claims (6)

A paper feed roller having a number of recesses on a cylindrical surface,
The plurality of recesses are arranged regularly in the axial direction and the circumferential direction of the paper feed roller so that the cylindrical surface interposed between the plurality of recesses forms a lattice pattern ,
The paper feed roller, wherein the cylindrical surface interposed between the adjacent recesses has a chevron shape having the adjacent recess as a skirt . The paper feed roller according to claim 1 , wherein the depth of the concave portion is 0.1 mm or greater and 1.0 mm or less. Said recess has a bottom surface, further recesses in the inner area of the bottom surface is provided, the paper feed roller according to claim 1 or 2. The depth of the bottom surface of the recess is 0.1 mm or greater and 1.0 mm or less, and the depth of the recess further provided in the inner region of the bottom surface is 0.01 mm or greater and 1.0 mm or less. The paper feed roller according to 3 . The axial length of the cylindrical surface interposed between the recesses adjacent in the axial direction, and the circumferential length of the cylindrical surface interposed between the recesses adjacent in the circumferential direction are 0. The paper feed roller according to any one of claims 1 to 4 , which is 2 mm or more and 1.0 mm or less. The ratio S2 / S1 of the area (S2) of the plurality of recesses over the entire cylindrical surface to the area (S1) of the cylinder surface interposed between the plurality of recesses is in the range of 0.5 to 5. The paper feed roller according to any one of claims 1 to 5 , wherein

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