Pagewidth inkjet printhead assembly with nozzle arrangements having actuator arms configured to be in thermal balance when in a quiescent state

1. A pagewidth inkjet printhead assembly having a plurality of nozzle arrangements each comprising:

walls defining an ink chamber having an ink supply channel and an ink ejection port having an ink spreading prevention rim; and

a thermal actuator mechanism configured to operatively eject ink from the chamber via the ejection port, wherein the mechanism includes an actuator arm having two layers which are formed from a conductive, resiliently flexible material, said layers surrounding a central material layer so that said two layers are in thermal balance with the arm in a quiescent state.

2. The pagewidth inkjet printhead assembly of claim 1 , wherein the ink spreading prevention rim defines a pit for preventing ink from flowing across a surface of the ink jet printhead and affecting operation of said printhead.

3. The pagewidth inkjet printhead assembly of claim 1 , wherein the thermal actuator mechanism includes an end paddle attached to an actuator arm which pivots at a post proximate the ink chamber.

4. The pagewidth inkjet printhead assembly of claim 1 , wherein the conductive material includes titanium nitride.

5. The pagewidth inkjet printhead assembly of claim 1 , wherein the actuator mechanism is actuated by electrical heating of one layer of the actuator arm to provide thermal bending to eject ink from the ink chamber.

6. The pagewidth inkjet printhead assembly of claim 1 , which is manufactured according to micro-electromechanical system (MEMS) techniques.

7. The pagewidth inkjet printhead assembly of claim 6 , wherein the nozzle rim and ink spread prevention rim are formed via a chemical mechanical planarization technique.