Patent ID: 8246133

Claim:
A liquid jet apparatus comprising: a plurality of nozzles; an actuator provided for each nozzle and connected to the respective nozzle; and a drive unit that applies a drive signal to the actuator, wherein the drive unit includes: a drive waveform signal generation unit that generates a drive waveform signal for controlling the operation of the actuator; a modulator unit that pulse-modulates the drive waveform signal to produce a modulated signal; a digital power amplifier having a plurality of transistors connected in parallel to a power supply for power-amplifying the modulated signal to produce an amplified signal; a low-pass filter for smoothing the amplified signal to produce the drive signal and supplying the actuator with the drive signal; and a number of transistors adjusting unit that adjusts the number of drive transistors of the digital power amplifier in accordance with the number of actuators to be driven, wherein the number of transistors adjusting unit decreases the number of drive transistors when the number of actuators to be driven is less than or equal to a threshold amount, and increases the number of drive transistors when the number of actuators to be driven is greater than the threshold amount.