Patent ID: 7600838

Claim:
An ink-droplet jetting apparatus which forms one dot by jetting a plurality of droplets of an ink on to a recording medium, comprising: a pressure chamber in which the ink is filled; an ink channel which communicates with the pressure chamber and which is elongated in a predetermined direction; an actuator which faces the pressure chamber, and which changes a volume of the pressure chamber to jet the droplets of the ink; and a signal control unit which supplies a drive pulse signal for driving the actuator to form the one dot, the drive pulse signal including: a first main pulse for a jetting operation; a first regulating pulse for suppressing a residual vibration of the ink in the pressure chamber caused by the first main pulse, the first regulating pulse being inserted at a first interval from the first main pulse; a second main pulse for the jetting operation, the second main pulse being inserted at a second interval from the first regulating pulse; and a second regulating pulse for suppressing a residual vibration of the ink in the pressure chamber caused by the second main pulse, the second regulating pulse being supplied after the second main pulse; wherein the first interval is in a range of 2 AL to 3 AL, and the second interval is in a range of 3 AL to 6 AL, provided that AL is a time during which a pressure wave generated in the ink channel communicating with the pressure chamber due to the change in the volume of the pressure chamber, is propagated one way in a longitudinal direction of the ink channel.