| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing roller which is excellent in surface durability, is free of a development defect by rotation unevenness and drive gear damage, is fixed between shafts and is optimum for use at a prescribed contact width. SOLUTION: The developing roller is constituted by concentrically forming rubber layers having an electrical conductivity in >=2 layers on the outer periphery of the revolving shaft 2 and forming the innermost layer 3 in contact with the revolving shaft of foamed rubber of 0.05 to 0.5 mm in a circle-equivalent average diameter of expansion cells and 5 to 25 in JIS A hardness. Cylindrical rubber stock is foamed by a cylindrical metal mold so as not to include the expansion cells of >=1 mm in diameter, The outermost layer is formed of thermoplastic polyurethane and silicone-acryl copolymer resins and fluororesin base particles are incorporated therein, by which the effect is made higher. |
