Patent ID: 6886920

Claim:
A method for operating a liquid drop emitter, said liquid drop emitter comprising a chamber, filled with a liquid, having a nozzle for emitting drops of the liquid; a thermal actuator having a cantilevered element extending from a wall of the chamber and a free end residing in a first position proximate to the nozzle for exerting pressure on the liquid at the nozzle, the cantilevered element including a first layer constructed of an electrically resistive material patterned to have a first resistor segment and a second resistor segment and a coupling device, and a second layer constructed of a dielectric material having a low coefficient of thermal expansion and attached to the first layer; and electrodes connected to first and second resistor segments to apply an electrical pulse to heat the first layer, the method for operating comprising: (a) determining an electrical pulse energy, E max , and power, P max , which results in the formation of vapor bubbles in the liquid contacting the cantilevered element near the coupling device; (b) applying an electrical pulse of energy E op and power P op to eject a liquid drop, wherein E op <0.9 E max , and P op <0.9 P max .