Driving device and driving method for ink jet printing head

Abstract

A driving device for driving an ink jet printing head having N (N=1, 2, 3, . . . ) nozzles includes a waveform generation circuit, three voltage amplification circuits, N multiplexers, and N current amplification circuits. The waveform generation circuit generates three waveforms for three driving signals VD , VD and VD corresponding to ink drop sizes “large”, “middle” and “small”. The three voltage amplification circuits amplify the voltage levels of the three waveforms respectively and thereby outputs the driving signals VD , VD and VD . Each of the N multiplexers corresponding to the N nozzles selectively transmits zero or one of the driving signals VD , VD and VD supplied from the voltage amplification circuits. Each of the N current amplification circuits corresponding to the N multiplexers amplifies the current level of the driving signal that has passed the corresponding multiplexer and thereby supplies the current-amplified driving signal to a corresponding piezoelectric actuator. The current amplification circuit is designed to have high input impedance, and the voltage amplification circuit is provided with an impedance conversion circuit and a feedback circuit for reducing its output impedance. By such composition of the driving device, precise and distortion-free driving signals can be supplied to the piezoelectric actuators and thereby high quality printing can be realized even when the frequency of the driving signal is high and even when a plurality of piezoelectric actuators of high load capacitance have to be driven.