| 摘要 |
PURPOSE:To shorten the time necessary for an increase in toner density even when the toner density is extremely low, by dividing the toner density lower than a reference value into two stages and making the width of an on pulse different for intermittent supplementation. CONSTITUTION:The resistance of a photocell 8b varies with the toner density and the voltage Vi at a connection point (a) rises in proportion to the toner density. Voltages corresponding to the 1st reference value alpha as the lower limit of a proper range of the toner density and the 2nd reference value beta less than it are Valpha and Vbeta respectively. When V1<Valpha, a solenoid 11d is operated to supplement a toner solution. When Vbeta<V1<Valpha, a relay 9c is not energized and a timer circuit 9e shortens the width of the on pulse of an intermitten supplement signal. When V1<Vbeta, the relay 9c is energized and the timer circuit 9e increases the width of the on pulse. |
