Patent ID: 8764143

Claim:
An image forming apparatus comprising: a plurality of heads, each of which includes a capacitive load used as an actuator for discharging ink; a drive-voltage generating circuit that outputs a drive voltage to be applied to the actuator and includes a plurality of current amplifying circuits; and a plurality of head drivers each of which controls each of the actuators of the heads, wherein each of the current amplifying circuits is configured to include a plurality of bipolar transistors and to operate so as to equalize output current loads of the bipolar transistors included in the current amplifying circuits, waveforms of the drive voltages output from the current amplifying circuits are combined to form a combined waveform of the drive voltages to be applied to each of the head drivers, each of the current amplifying circuits is a class-B amplifier system that includes a bipolar transistor configured to have an inverted Darlington system that includes: a front stage, which is a common-emitter amplifier circuit that includes a plurality of bipolar transistors; and a rear stage, which is a common-collector amplifier circuit that includes a plurality of bipolar transistors, and at least the rear stage includes the plurality of common-collector amplifier circuits that are connected in parallel with each other.