DEVELOPER CONVEYANCE DEVICE, DEVELOPING DEVICE, AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a configuration to keep supplying a certain amount of toner even if the amount of toner to be supplied to a developing device by air-flow conveyance is reduced to increase the amount of air.SOLUTION: A developer conveyance device 190 includes: a developer container 70 to be replaced when developer contained inside is used up; a developer housing unit 60 for supplying a predetermined amount of developer discharged from the developer container 70 to a developing unit; and a positive-displacement pump 30 which generates positive pressure and negative pressure according to changes in volume in each predetermined driving period, and discharges the developer from the developer housing unit 60 to the developing unit 10. The developer in the developer container 70 decreases according to consumption. When it is determined that the developer has been used up, developer conveyance performance of the positive-displacement pump 30 is made lower than that exhibited before the developer has been used up.