Inkjet printhead having thermal bend actuator heating element electrically isolated from nozzle chamber ink

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 movable element have substantially the same composition with the conductive heating circuit layer defining a discontinuation between the first and second portions so that the first and second portions are electrically isolated from one another so that electric energy in said heating circuit layer is not conducted by the actuator to said ink.