| 摘要 |
PROBLEM TO BE SOLVED: To perform gradation printing by varying ink ejection from an ink chamber through simple control. SOLUTION: A triangular reference voltage waveform is outputted from a power supply circuit 12 and applied to a piezoelectric member 11i. A transistor 13i corresponding to a piezoelectric member being driven is turned on simultaneously with application of the reference voltage waveform to the piezoelectric member. Consequently, an ink chamber is opened. Subsequently, the transistor is turned off temporarily immediately before the reference voltage waveform falls abruptly below the ground potential. The piezoelectric member thereby holds the charges and its displacement position. The ink chamber is supplemented with ink at that time. Upon elapsing an appropriate holding time, the transistor is turned on again and the piezoelectric member is reset to steady state. Consequently, the ink chamber is returned back to the original state abruptly and ink is ejected from the ink chamber. Since ink ejection can be varied by varying the holding time, gradation printing can be effected. |
