| 摘要 |
PROBLEM TO BE SOLVED: To suppress the chemical attack to a resin or a rubber material. SOLUTION: A rolling bearing 3 comprises an inner ring 3a fitted to an outer circumference of a shaft end of a photosensitive drum 11, an outer ring 3b fitted to an inner circumference of a housing 2, a plurality of balls 3c interposed between a raceway surface 3a1 of the inner ring 3a and a raceway surface 3b1 of the outer ring 3b, a holder 3d to hold the balls 3c at a predetermined space of the circumference, a seal 3e to seal the inside of the bearing, and a conductive grease 3f sealed inside the bearing. The housing 2 is formed of the resin mainly consisting of acrylonitrile-butadiene-styrene(ABS) or polycarbonate, and in order to suppress the chemical attack to the housing 2, the conductive grease 3f is formed of mineral oil or synthetic hydrocarbon oil for the base oil. The kinetic viscosity of the base oil at 40 deg.C is adjusted to 18-60 mm2/s. |
