Patent attributes
A method for determining the pulse width for driving printhead nozzles in a thermal inkjet printer. The printhead is preheated to a desired temperature during a maintenance mode. The printhead nozzle heaters are successively driven in respective heating intervals, where each successive heating interval is characterized by shorter drive pulse width pulses occurring at a higher pulse frequency. The printhead temperature data received during each heating interval is processed to determine a respective temperature slope. The temperature slopes are compared to a desired threshold temperature slope, and when a match is found, the pulse width associated with the matched temperature slope is used to drive the nozzle heaters during subsequent printer operations to print characters on a print medium.