Sheet conveying roller and production method therefor
The present invention provides a sheet conveying roller, which effectively reduces the amount of paper dust accumulated on its outer peripheral surface to thereby suppress sheet transportation failure. The sheet conveying roller includes a nonporous tubular elastic member ( 1 ). The elastic member ( 1 ) has a plurality of recesses ( 6 ) or a plurality of through-holes ( 8 ) equidistantly arranged in a center axis (L 1 ) direction thereof and equidistantly arranged in a circumferential direction thereof, and each having an opening having a round plan shape in an outer peripheral surface ( 2 ) thereof, wherein the recesses ( 6 ) each have a constant depth as measured thicknesswise of the elastic member ( 1 ), wherein the through-holes ( 8 ) each extend thicknesswise through the elastic member ( 1 ). A production method includes forming the elastic member by vulcanizing a rubber composition in a vulcanization mold having projections corresponding to the recesses or the through-holes.
1. A method of producing a sheet conveying roller including a nonporous tubular elastic member having a plurality of columnar through-holes extending through the elastic member, the method comprising the steps of:
(1) providing a vulcanization mold which includes an outer mold and an inner mold,
the outer mold being circumferentially dividable into at least two mold pieces, and having a shape-imparting tubular inner surface having an inner diameter equal to a sum of an outer diameter of the tubular elastic member and a predetermined grinding margin,
the inner mold having a shape-imparting tubular outer surface to be located coaxially with the shape-imparting inner surface so as to be spaced a distance equal to a sum of a thickness of the elastic member and the grinding margin from the shape-imparting inner surface, and a plurality of projections projecting radially outward from the shape-imparting outer surface and each having a sectional shape corresponding to a plan shape of the columnar through-holes of the elastic member and a projection height that is not less than the thickness of the elastic member and less than the sum of the thickness of the elastic member and the grinding margin, and
forming a nonporous tubular elastic body having a plurality of columnar recesses corresponding to the projections in an inner peripheral surface of the elastic body by preheating the vulcanization mold, locating the shape-imparting inner surface of the outer mold and the shape-imparting outer surface of the inner mold of the vulcanization mold coaxially with each other, filling a space defined between the shape-imparting inner surface and the shape-imparting outer surface with a rubber composition as a material for the elastic member, and vulcanizing the rubber composition; and
(2) grinding an outer peripheral portion of the elastic body by the grinding margin to expose the columnar recesses in an outer peripheral surface of the resulting elastic body to form the plurality of through-holes in the elastic member.