Patent ID: 8882646

Claim:
A semiconductive roller comprising: a roller body having an outer peripheral surface made of a semiconductive rubber composition; and an oxide film formed by ultraviolet irradiation covering the outer peripheral surface of the roller body, wherein the semiconductive rubber composition contains a base polymer, a crosslinking component for crosslinking the base polymer, 3 to 7 parts by mass based on 100 parts by mass of the base polymer of a metallic oxide or aliphatic acid vulcanization accelerator, and 1 to 5 parts by mass based on 100 parts by mass of the base polymer of an acid acceptor, the base polymer is a mixture of a bicopolymer E containing epichlorohydrin and nitrile-butadiene rubber N, while the mass ratio E/N of the bicopolymer E and the nitrile-butadiene rubber N in the mixture is 50/50 to 80/20, and the crosslinking component includes (i) 0.3 to 1 part by mass with respect to 100 parts by mass of the base polymer of a thiourea-based crosslinking agent and 0.3 to 1 part by mass based on 100 parts by mass of the base polymer of a guanidine-based crosslinking accelerator for crosslinking the bicopolymer E, and (ii) a sulfur-based vulcanizing component for vulcanizing the nitrile-butadiene rubber N, which sulfur-based vulcanizing component provides 1 to 2 parts by mass based on 100 parts by mass of the base polymer of sulfur and which sulfur-based vulcanizing component comprises 1 to 2 parts by mass based on 100 parts by mass of the base polymer of a thiazole-based vulcanization accelerator and 0.3 to 0.9 parts by mass based on 100 parts by mass of the base polymer of a thiuram-based vulcanization accelerator.