SHEET CONVEYING ROLLER, SHEET CONVEYING APPARATUS, AND IMAGE FORMING APPARATUS

Abstract

A shaft of a sheet conveying roller is a pipe shaft. Both ends of the pipe shaft are formed into small-diameter portions, and a mounted portion on which a friction member is provided is formed into a large-diameter portion, which has a diameter larger than a diameter of the both ends of the pipe shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view taken along the sheet conveying direction of an image forming apparatus in an embodiment of the present invention.

FIG. 2A is a perspective view of a sheet conveying roller of a first embodiment, and FIG. 2B is a cross sectional view taken along the axial direction of the sheet conveying roller of the first embodiment.

FIG. 3A is a plan view of a sheet conveying roller of a second embodiment, and FIG. 3B is a cross sectional view taken along the axial direction of the sheet conveying roller of the second embodiment.

FIG. 4A is a plan view of a sheet conveying roller of a third embodiment, FIG. 4B is a cross sectional view taken along the line IVB-IVB in FIG. 4A, and FIG. 4C is a cross sectional view taken along the line IVC-IVC in FIG. 4B.

FIG. 5A is an appearance perspective view of a sheet conveying roller of a fourth embodiment, FIG. 5B is a plan view of the sheet conveying roller of the fourth embodiment, FIG. 5C is a cross sectional view taken along the line VC-VC in FIG. 5B, and FIG. 5D is a cross sectional view taken along the line VD-VD in FIG. 5B.

FIG. 6A is an enlarged plan view of an engaging portion of a rubber roller and a pipe shaft shown in FIG. 5A, and FIG. 6B is a cross sectional view taken along the line VIB-VIB in FIG. 6A.

Claims

1. A sheet conveying roller comprising: a shaft supported by bearings at both ends thereof; andan elastic frictional member provided on an outer circumference of the shaft,wherein the shaft is a pipe shaft, the both ends of the pipe shaft are formed into small-diameter portions, and a mounted portion on which the frictional member is mounted is formed into a large-diameter portion having a diameter larger than a diameter of the both ends.

2. A sheet conveying roller according to claim 1, wherein the pipe shaft has a plurality of large-diameter portions and has an intermediate small-diameter portion between the large-diameter portions, the intermediate small-diameter portion having a diameter smaller than the diameter of the large-diameter portions.

3. A sheet conveying roller according to claim 2, wherein the intermediate small-diameter portion is supported by a supporting member.

4. A sheet conveying roller according to claim 1, further comprising a tear member positioned between the large-diameter portion and the friction member provided around the large-diameter portion so as to tear the friction member when the tear member is pulled in a direction away from the large-diameter portion.

5. A sheet conveying roller according to claim 1, wherein the friction member is mounted on the large-diameter portion by engaging an engaging portion formed on the friction member with an engaged portion formed in the large-diameter portion.

6. A sheet conveying roller according to claim 1, wherein the friction member is mounted on the large-diameter portion in a C-shaped cross section, while an engaging portion is detachably attached to an engaged portion.

7. A sheet conveying roller according to claim 6, wherein a chevron portion and a valley portion are formed on opposite ends of the C-shaped cross section of the friction member so that the chevron portion and the valley portion intermesh with each other.

8. A sheet conveying roller according to claim 1, wherein a flat surface is formed along an axial direction of the large-diameter portion, engaged portions are formed on both sides of the flat surface.

9. A sheet conveying roller according to claim 1, wherein the pipe shaft has a uniform wall thickness.

10. A sheet conveying roller according to claim 1, wherein a hole is formed in the large-diameter portion, a projection is formed on the friction member, and the projection of the friction member is inserted into the hole so that the friction member is locked to the pipe shaft.

11. A sheet conveying apparatus comprising a sheet conveying roller, which conveys a sheet, the sheet conveying roller being a sheet conveying roller as recited in claim 1.

12. An image forming apparatus comprising: an image forming portion configured to form an image on a sheet; anda sheet conveying roller configured to convey the sheet on which the image is formed by the image forming portion, the sheet conveying roller being a sheet conveying roller as recited in claim 1.