| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device which can perform satisfactory image formation for a long period of time by minimizing changes in toner concentration and bulk level of developer in a trickle system developing device that uses two-component developer, and to provide an image forming apparatus.SOLUTION: The developing device includes a stirring member for conveying and stirring developer in a developing tank, and a developer carrier. The developing device further includes: a developer supply tank; a toner concentration detecting sensor; a trickle discharging mechanism; a developer quantity detecting means; and a control means for controlling the operation of supply of the toner and carrier to be supplied, when the toner concentration is lower than a predetermined reference toner concentration. Additionally, when the toner concentration detecting sensor detects that the current toner concentration is higher than the reference toner concentration by a predetermined value or more, the control means performs the operation of forcible consumption of toner in the developing tank and the operation of supply of the toner and carrier to be supplied. |
