Patent ID: 7874631

Claim:
A printhead integrated circuit for an inkjet printer, the printhead integrated circuit comprising: a nozzle and a corresponding actuator for ejecting ink through the nozzle; drive circuitry for controlling the operation of the actuator, the drive circuitry having an open actuator test circuit comprising an open actuator test input, a column enable input and a row enable input; a drive transistor operatively linking said actuator to a power supply; a bleed transistor arranged in parallel with the actuator; a sense transistor operatively linking an output of the drive transistor and inputs of the actuator and bleed transistor to a sensing node, wherein during use, actuating the actuator to eject ink by enabling the column and row enable inputs to deactivate the bleed transistor and to activate the drive transistor to link the actuator to the power supply; and testing the actuator's continuity by enabling the open actuator test input to activate the sense transistor, so that the actuator is short-circuited and the sense node is pulled high if the actuator is open-circuit.