| 摘要 |
PROBLEM TO BE SOLVED: To excellently perform the developer density control for a developing device with respect to the cleaner less image forming device provided with plural image forming stations respectively forming the toner image in different color. SOLUTION: The developer D adopted in the developing device 4 consists essentially of magnetic carriers and non-magnetic toner. When recovering the transfer residual toner on a photosensitive drum 1 by developing devices on respective station, there is a case the toner of the different color is mixed in the developing device 4. Apparent magnetic permeable ratio of the developer D in the developing device 4 is detected by an inductance head 20, a controlling means 30 drives toner replenishing means 12 based on the detecting result to replenish the toner into the developing device 4. Since the developer density excellently is controlled, the excellent image quality can be always maintained while keeping the developer density to be constant. |
