Patent ID: 8702188

Claim:
A device for driving a liquid-drop ejection head that includes a plurality of nozzles each ejecting liquid, a pressure generating element that generates pressure for ejecting the liquid, provided for each of the nozzles, and a drive-waveform control unit that determines whether to apply a drive waveform having a plurality of pulses in one printing cycle to the pressure generating element and controls a timing to apply the drive waveform to the pressure generating element, the device selecting a desired pulse from the drive waveform, applying a selected pulse to the pressure generating element, and ejecting liquid drops of different sizes from a same nozzle for each printing cycle based on the selected pulse, the device comprising: a setting unit configured to set timings for the drive-waveform control unit to turn off the drive waveform such that at least two of the timings are concentrated in one position of the drive waveform, the one position being a position where a state in which a voltage of the drive waveform shows substantially no fluctuation is maintained for more than a moment during which a current of the drive waveform decreases to a level at which a noise that is large enough to cause a problem is not generated even when the drive waveform is turned off; and a selecting unit configured to sequentially select pulses present before the one position in time from the one position, wherein the device applies a pulse selected by the selecting unit to the pressure generating element.