DEVELOPING DEVICE AND IMAGE FORMING DEVICE

摘要

PURPOSE:To compensate variation in output value of a toner density sensor. CONSTITUTION:A control means 2 is provided to operate the developing part to agitate developer when electrical power source is connected after the image forming device is not activated and let stand. When the output value of a magnetic sensor 1 is greater than a specified toner concentration control value, the toner is replenished by the toner replenishing part to the developing part until the specified toner concentration control value is reached by the output value of the magnetic sensor 1.