Patent ID: 6969139

Claim:
A method of printing from a microelectromechanical inkjet (MEMJET) printhead, whereby ink is printed by being discharged as dots from a plurality of nozzles by means of pulses, the number of nozzles being sufficient to produce about 1600 dpi, said method comprising the steps of loading each nozzle with ink; preheating said printhead by the steps of: sensing the temperature of the ink in each nozzle; if the temperature of the ink is at a required temperature, printing said ink; if the temperature of the ink is below the required temperature, heating the ink by firing a short pulse to each nozzle, said pulses being insufficient to discharge ink from the nozzle, but sufficient to heat up the ink; sensing the temperature of each nozzle; repeating the steps of heating the ink and sensing the temperature of each nozzle until the required temperature is reached, said preheating lasting for a period of up to about 5 ms; and printing said ink.