| 摘要 |
PURPOSE:To control toner density within a specific range all the time, by always supplementing toner during a developing operation period following a developing operation period wherein toner is supplemented. CONSTITUTION:The density of excessive toner attaining to a constant flow rate is detected through a detection coil 18 during a period D1 after an inhibition period B1 in a developing operation period A1, and toner density detected by a counter 28 and reference toner density from a setting circuit 29 are compared with each other by a comparator 30. Then, when the detected toner density is lower than the reference density, a monostable multivibrator 32 is triggered through the comparator 30 and a signal passed through an AND gate 32 is a toner supplement signal. In response to this signal, toner is supplemented in the remaining time I1 of the period A1 after the period D1, and a toner supplement period I2 corresponding to the entire developing operation period A2 is set; toner is always supplemented during the next developing operation period following the developing operation period wherein the toner is supplemented to eliminate a decrease in toner density below its limit due to deficient toner supplement, controlling the toner density within the specific range. |
