Patent ID: 7946674

Claim:
A printhead IC comprising: an array of nozzles; a plurality of ejection actuators each corresponding to each of the nozzles respectively, each ejection actuator having a resistive heater for heating ink and effecting ejection of the ink through the corresponding nozzle; drive circuitry for receiving print data and activating the plurality of ejection actuators with drive signals in accordance with the print data; and, open actuator test circuitry for selectively disabling an ejection actuator upon receipt of a drive signal while comparing a resistance of the resistive heater of the ejection actuator, the open actuator test circuitry comparing the resistance of the resistive heater to a predetermined threshold to assess whether the ejection actuator is defective, wherein, the open actuator test circuitry includes a bleed transistor for bleeding a voltage from the ejection actuator to eliminate any electrolysis path therein, and the open actuator test circuitry is configured to perform the assessment of the ejection actuator periodically and before the voltage is fully bled from the ejection actuator by the bleed transistor, the defective nozzle feedback being used to adjust the print data subsequently received by the drive circuitry.