Patent ID: 7036912

Claim:
A printhead chip which comprises a substrate that defines ink supply conduits; drive circuitry positioned on the substrate; nozzle chamber assemblies positioned on the substrate, each nozzle chamber assembly defining a nozzle chamber in fluid communication with a respective ink supply conduit and having an upper portion that defines an ink ejection port in fluid communication with the nozzle chamber and a lower portion that extends from the substrate, the upper portion being reciprocally displaceable with respect to the lower portion so that ink is ejected from the ink ejection port; and elongate actuators connected between the substrate to be electrically connected to the drive circuitry and respective said upper portions to displace said upper portions to eject ink on receipt of electrical signals from the drive circuitry, wherein each actuator has at least one longitudinal portion with a substantially U-shaped cross section to enhance structural integrity of the actuator.