| 摘要 |
PURPOSE:To prevent the life of a piezoelectric actuator from becoming short due to moisture absorption by applying an alternating voltage to the piezoelectric actuator which drives a film thickness control mechanism and causing the piezoelectric actuator to generate heat for itself. CONSTITUTION:A gap 4 between an ink supply roller 2 and an adjustment blade 3 is adjusted by displacing the adjustment blade 3 using a piezoelectric actuator 5. In addition, a drive voltage consisting of a direct voltage VDC overlapped with a high-frequency voltage VAC is applied to the piezoelectric actuator 5. The direct voltage VDC is a signal for film thickness adjustment and the alternating voltage VAC is a signal for causing the piezoelectric actuator t6 generate heat internally for itself due to hysteresis loss or dielectric loss and a high-frequency voltage which is higher than the response frequency of the film thickness. |
