DRIVER FOR INK JET HEAD AND INK JET HEAD EQUIPPED WITH DRIVER

摘要

PROBLEM TO BE SOLVED: To stably eject ink drops of different diameters by utilizing a pulse voltage. SOLUTION: An actuator having a laminate of a piezoelectric element of 3μm, a diaphragm of 2μm and an individual electrode of 0.1μm is provided. Since the actuator has a low eigen frequency, it is displaced with a lag behind application of the pulse voltage. A drive circuit applies a first pulse voltage P1 having pulse width narrower than 1/4 of the natural period of the actuator or a second pulse voltage P2 having pulse width narrower than that of the first pulse voltage P1 selectively to the piezoelectric element. Both pulse voltages P1, P2 have same voltage level. The actuator is displaced by an amount L1 upon application of the first pulse voltage P1 and ejects an ink drop of large diameter. When the second pulse voltage P2 is applied, it is displaced by an amount L2 (