| 摘要 |
PROBLEM TO BE SOLVED: To easily maintain a transporting quantity of the developer in a specified range, and to effectively prevent deterioration in picture quality due to the transporting quantity fluctuation of the developer. SOLUTION: This developing device of non-contact two component developing system, is provided with a magnetic roll 4 equipped with plural developing magnet poles 6 of same magnetic force in different polarity alternately arranged with the same space over the range wider than an effective developing area Y of an electrostatic latent image carrier 1 the trimming magnet poles 7 for attracting the developer arranged on the upstream side of the developer layer thickness control member 5, and magnetic roll position variable means 8 capable of rotating the magnetic roll 4 stepwise corresponding to a pitch (p) between the developing magnet poles 6, and fixed supported on an optional position. Moreover, the device is provided with toner density detecting means 9 detecting the toner density of the developer in the developing device, and the magnetic roll position determining means 10 determining the setting angle position of a magnet roll 4 corresponding to the detected toner density and actuating the magnetic roll position variable means 8. |
