| 摘要 |
PURPOSE:To improve abrasion resistance of the title roller while keeping its low hardness by constituting the roller of a ternary copolymer having <=50 deg.C hardness (JIS A scale) and consisting of propylene oxide, epichlorohydrin, and allyl glycidyl ether. CONSTITUTION:The title roller is constituted of a ternary copolymer consisting of propylene oxide, epichlorohydrin, and allyl glycidyl ether having <=50 deg. hardness (JIS A scale). Addition of a plasticizer is unnecessary in order to obtain a product of low hardness from the terpolymer unlike general elastic rubber. Moreover, the terpolymer (among several kinds of rubber) has a low electric resistance and a volume resistance, so the electric resistance of the terpolymer can be reduced to a value suitable for a developing roller by the addition of a small amt. of a conductivity imparting agent. Accordingly, the increase of hardness due to the increase of conductivity can be restricted to a minimum degree. Thus, a developing roller having sufficient abrasion resistance in spite of its low hardness, causing no oozing of a plasticizer, and being able to provide stable picture images for over a long time, is obtd. |
