US Patent 7556327 Charge leakage prevention for inkjet printing

Charge leakage prevention and voltage drift prevention on a droplet ejection device for an inkjet printer. In one method to prevent charge leakage on a droplet ejection device with a switch and a piezoelectric actuator, the method includes controlling the switch to drive the piezoelectric actuator with the waveform input signal during a droplet firing period, and controlling the switch to drive the piezoelectric actuator with a constant voltage level during a non-firing period.