| 摘要 |
PURPOSE:To always attain optimum toner replenishment by changing the detecting interval of an optical sensor based on the result of comparing a toner sticking quantity detecting output from the optical sensor with a preset reference value. CONSTITUTION:When copying is started and reaches a prescribed number at which the toner quantity sticking to a specific pattern should be detected, the sticking quantity is detected by the optical sensor 6. The detected value is compared with the reference value stored in a ROM 12, a motor 9 is driven for a prescribed period based on a deviation from the reference value, and the prescribed quantity of the toner is supplied into a developing device. When the toner replenishing quantity becomes large, the detecting interval of the sensor 6 is shortened, whereas it is becomes small, the detecting interval is brought into the reference condition. Thus, excessive toner replenishment is prevented and the optimum toner replenishment is attained, hence a high grade image can be formed. |
