Patent ID: 6899409

Claim:
An ink jet head driving apparatus comprising: an ink jet head having a pressure chamber which contains ink, a nozzle communicating with the pressure chamber, through which the ink in the pressure chamber is ejected in the form of a droplet to a recording medium, and an actuator which changes a capacity of the pressure chamber to be expanded or contracted; and a drive signal generating unit which outputs a drive signal including a first, second, third and fourth pulses sequentially applied to the ink jet head for ejecting one ink droplet by the actuator, the first pulse having a first rectangular wave which expands the capacity of the pressure chamber, the second pulse having a second rectangular wave which contracts the capacity of the pressure chamber, the third pulse having a third rectangular wave which expands the capacity of the pressure chamber, and the fourth pulse having a fourth rectangular wave which contracts the capacity of the pressure chamber, wherein both a first time interval between centers of pulse widths of the first and third pulses and a second time interval between centers of pulse widths of the second and fourth pulses are respectively set to half of an acoustic resonant cycle of the ink in the pressure chamber.