Patent ID: 7111924

Claim:
An ink jet printhead comprising a plurality of nozzle devices formed on a substrate, each nozzle device comprising: a nozzle chamber, a nozzle opening through which ink from the nozzle chamber is ejected, a movable element in contact with ink in the nozzle chamber to cause said ejection of ink, a thermal bend actuator having a proximal end anchored to the substrate and a distal end connected to the movable element, the actuator including a first portion adjacent the proximal end external to the nozzle chamber and having a conductive heating circuit layer for heating the actuator, and a second portion extending to said movable element and in contact with said ink, wherein said actuator and said movable element have substantially the same composition, the heating circuit layer defining a discontinuation between the first and second portions for electrically isolating said first and second portions so that electric energy in said heating circuit layer is not conducted by the actuator to said ink.