| 摘要 |
PURPOSE:To replenish a great quantity of toner to compensate even when the toner concentration is rapidly reduced inside the developer. CONSTITUTION:A toner concentration sensor 16 is provided to detect the toner concentration of the developer contained in a developing device main body 1. A toner replenishing opening 14 is provided in a boundary part between a developing device main body 1 and a toner case 2. An agitator 11 is provided in the toner case 2. When the rapid reduction of toner concentration is detected by the toner concentration detection sensor 16, the rotational speed of an agitator 11 is increased so that the toner replenishing quantity from the toner replenishing opening 14 is increased. |
