| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic field generating layer capable of holding magnetic force sufficient for carrying toner, making a shape fluctuation and reduction in strength extremely little with respect to long-term use and an environmental fluctuation and keeping a prescribed electric resistance value with respect to a fluctuation with the lapse of time and the environmental fluctuation, in a developing roller for permitting a core shaft to move the roller center of a roller layer part consisting of a shape keeping layer and the magnetic field generating layer. SOLUTION: This developing device is provided with the core shaft 2 freely rotatably supported, an intermediate part provided to rotate integrally with the core shaft 2, the shape keeping layer 4 which is provided to rotate integrally with the intermediate part and has rigidity higher than that of the intermediate part and the magnetic field generating layer 5 formed integrally with the shape keeping layer 4. The intermediate part, is constituted as a movement permission part for the roller center B for allowing the core shaft 2 to move the roller center B of the roller layer part, consisting of the shape keeping layer 4 and the magnetic field generating layer 5. The magnetic field generating layer 5 has magnetic substances dispersed in resin whose volume resistivity variation is >=10<4>Ω.cm.
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