| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device excellent in the self controllability of toner concentration and capable of obtaining an excellent image without causing any density irregularity by regulating the lower limit of the minimum value (Frmin) of the radial-direction magnetic force of a developer carrier acting on developer in a developer housing part. SOLUTION: A magnet roller 5 arranged in an area opposed to the inside of the developer housing part A is provided with only one magnetic pole and a magnetic filed in the housing part A is continuously and smoothly changed. Then, the minimum value (Frmin) of the radial-direction magnetic force of the developer carrier acting on the developer in the housing part A is set so as to satisfy the expression of Frmin>1.5×10-7 (N). Provided that the direction of the radial-direction magnetic force that the developer is attracted to the developer carrier is positive. |
