Patent ID: 7988247

Claim:
A method for causing ink to be ejected from an ink chamber of an ink jet printer, the method comprising: selecting a combination of ejection pulses from a palette of pre-defined ejection pulses to form an excitation waveform, wherein at least two of the pre-defined ejection pulses are different, and the excitation waveform includes a number of ejection pulses equal to or less than a total number of ejection pulses from the palette, applying a first pulse from the excitation waveform to an active wall of the ink chamber to cause a first bolus of ink to be extruded from the ink chamber; following lapse of a selected interval, applying a second pulse from the excitation waveform to cause a second bolus of ink to be extruded from the ink chamber; wherein the interval is selected to be greater than the reciprocal of the fundamental resonant frequency of the chamber, and wherein the interval is selected such that the first bolus remains in contact with ink in the ink chamber at the time that the second bolus is extruded, whereby in an ink drop that includes the first and second boluses, the first and second boluses remain connected by a ligament as the ink drop leaves an orifice plate of the ink jet printer, wherein the ink drop formed from the first and second boluses has a velocity different from an ink drop formed from a single bolus, and wherein each ejection pulse in the excitation waveform includes a pulse amplitude and a pulse delay, the pulse delay is the time between a start of an excitation waveform and a start of the ejection pulse, and the method further comprises selecting ejection pulses with pulse amplitudes and pulse delays such that a drop lifetime of the ink drop that contains the first and second boluses is equal to a drop lifetime of the ink drop formed from the single bolus of ink.