| 摘要 |
PROBLEM TO BE SOLVED: To obtain satisfactory development performance by making a conductive substrate hollow, and setting deflection of the diameter of the conductive substrate and deflection of the diameter of the roller in which only a conductive and elastic layer is formed around the conductive substrate to the specific value or below of the thickness of the conductive and elastic layer. SOLUTION: This developing roller 4 is composed of a conductive substrate 3, a cylindrical, conductive and elastic layer 2 on the periphery of the conductive substrate 3, and a surface layer 1 on the periphery of the conductive, elastic layer 2. In this case, the conductive substrate 3 is made hollow. Further, deflection of the diameter of the conductive substrate 3 and deflection of the diameter of the developing roller 4 in which only the conductive and elastic layer 2 is formed around the conductive substrate 3 are controlled to <=0.01 times of the thickness of the conductive elastic layer 2. In such a structure, since the conductive substrate 3 is hollow, weight is very light, the dimensional precision of the conductive substrate 3 and conductive and elastic layer 2 are high, a stable abutting area can be formed between an electrostatic-latent-image carrier and the developing roller, the satisfactory development can be performed. |
