| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a trickle-type developing device using two-component developer, and an image forming apparatus, where an appropriate amount of developer is replenished in accordance with toner concentration and an amount of developer, then, images are satisfactorily formed over a long period of time. <P>SOLUTION: The developing device includes: a stirring member for conveying/stirring the developer in a developing tank; and a developer carrier. The developing device also includes: a developer replenishment tank; a toner concentration detecting sensor; a trickle type discharge mechanism; a developer amount estimation sensor; and a control means that controls the replenishment operation of replenishing the replenishment toner and carrier to the developing tank when the toner concentration is lower than a predetermined reference toner concentration. The control means determines the amount of toner and carrier to be replenished, based on the calculated toner concentration and the estimated amount of developer. <P>COPYRIGHT: (C)2010,JPO&INPIT |
