| 摘要 |
PURPOSE: To make the volume resistivity in the longitudinal direction of a roller uniform and to perform the uniform electrifying treatment in the longitudinal direction of the roller without generating the electrification defect under low temperature and low humidity conditions in a contact electrifying roller, for instance, with respect to a conductive sponge roller having a conductive sponge layer, and being used by applying the voltage. CONSTITUTION: In the roller which has the conductive sponge layer 17 being at least a foamed layer and is used by applying the voltage, the volume resistivity along the longitudinal direction of the roller on the conductive sponge layer 17 or roller surface is almost uniformalized, irrespective of a larger foaming ratio of the conductive sponge layer 117 in the vicinity of both end parts of the roller than that in the vicinity of the central part in the longitudinal direction of the roller because of larger diffused quantity of a conductive material in the conductive sponge layer 17 in the vicinity of both end parts of the roller than that in the vicinity of the central part in the longitudinal direction of the roller, or because of the almost uniformalized foaming ratio along the longitudinal direction of the roller in the conductive sponge layer 17. |
