| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device capable of stabilizing toner concentration and image density without requiring complicated, expensive toner supply system. SOLUTION: A control circuit 4 controls a toner supply driving section 16 such that when a printing rate is high wherein a detection level of a dot counter 17 is high, and if a toner concentration detected by a toner concentration sensor 26 is higher than a threshold toner, the quantity of which is smaller than a quantity of supply toner calculated on the basis of the detection level of the dot counter 17 is supplied. COPYRIGHT: (C)2008,JPO&INPIT |
