Printhead integrated circuit having sensing and test circuitry

Abstract

A printhead IC is provided having ejection nozzles, drive circuitry for sending drive pulses to resistive heaters of the nozzles to cause ejection from the nozzles, sensing circuitry being activated to sense the temperature of the printhead IC and adjust the profile of the sent drive pulses in accordance with the sensed temperature and being de-activated after a period of use, and test circuitry for selectively disabling the resistive heaters when they receive the drive pulses while comparing the resistance of the resistive heaters against a predetermined threshold to assess whether the resistive heaters are defective.

Dependencies are inferred from the claim text.