ELASTIC MATERIAL OF ELECTRICALLY SEMICONDUCTIVE POLYMER

摘要

PROBLEM TO BE SOLVED: To suitably use an elastic material as an electroconductive roller for electrophotography without generating reduction of its performance by elevation or change of a resistance value even when turning on electricity for a long time. SOLUTION: An elastic material of electrically semiconductive polymer uses a foam of foaming polyurethane as a base material wherein the electric resistance is 1×105 to 1×1010 [Ωcm] at a measured voltage of 1,000 V under a condition of 28 deg.C and at 85% relative humidity; the electric resistance is less than 5 times of the initial one when continuously turning on electricity for 8 hr under the same condition; and further the electric resistance at the measured voltage of 10 V under conditions of the same temperature/humidity is not more than 2 times of that at the measured voltage of 5,000 V.