| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing apparatus and an image forming apparatus, capable of preventing serious fault from occurring by restraining overcurrent in a current path via a toner supply area, when the absolute value of the surface potential of a developing roller is lowered to abnormalitive, without providing an automatic shielding circuit based on the detection of the excess current. SOLUTION: In this developing device equipped with the developing roller 402, a supply roller 403, a developing bias power source 412 and a toner supply bias power source 413, the electrical resistance between the surface of the roller 403 and the power source 413 is made larger than that between the surface of the roller 402 and the power source 412. For example, a protective resistance layer (high resistance part) 409, consisting of high resistance material, is formed on the surface of a sleeve 408 constituting the roller 403. |
