ELECTROSTATIC CHARGING ROLLER AS WELL AS PROCESS CARTRIDGE AND ELECTROPHOTOGRAPHIC DEVICE HAVING THIS ELECTROSTATIC CHARGING ROLLER

摘要

PROBLEM TO BE SOLVED: To provide an electrostatic charging roller which eliminates the unevenness of the electrostatic charges in the longitudinal direction of an electrostatic charging member by the deficiency in the amount of crown and the distortion of seamless tubes arising in coating and does not give rise to the image defects occurring therein as well as a process cartridge and electrophotographic device having this electrostatic charging roller. SOLUTION: The electrostatic charging roller characterized in that the electrostatic charging roller consisting of an arbor 1a, a foamed elastic body layer 2b of <=36 deg. in Asker C hardness on the outer periphery of the arbor and the simultaneously molded and multilayered seamless tubes 2c and 2d formed to coat the outer periphery of the foamed elastic body layer is composed of the material lower in the melting point of a thermoplastic resin used for the surface layers of the seamless tubes than the melting point of the thermoplastic resin used for at least one layer exclusive of the surface layers and that the electrostatic charging roller is heat treated at the temperature greater or equal the m.p. of the thermoplastic resin used for the surface layers below the melting point of the thermoplastic resin used for at least one layer exclusive of the surface layers as well as the process cartridge and electrophotographic device having such electrostatic charging roller.