| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device capable of appropriately controlling the concentration of toner even in the event that foreign matter enters the toner, and to provide an image forming apparatus using the developing device. SOLUTION: The developing device includes: a developer carrier 32; a developer storage section 33; a toner storage section 35; and toner supply means 38 and 40 for supplying toner in the toner storage section into the developer storage section; and a concentration detecting means SU. The concentration detecting means SU has a plurality of light emitting sources to emit light rays having two or more wavelengths. Using at least one of the wavelengths, the concentration detecting means SU measures the concentration of toner in two-component developer. Using another one of the wavelengths, different from the above-mentioned one, it also measures the concentration of foreign matter in the two-component developer, other than the toner. Based upon the results of the detections of the toner concentration and foreign matter concentration by the concentration detecting means SU, the toner supply means alter an amount of toner supply. COPYRIGHT: (C)2006,JPO&NCIPI |
