Patent ID: 7549726

Claim:
A printhead for an inkjet printer, the printhead comprising a wafer assembly defining a plurality of spaced apart groups of ink supply channels and a plurality of groups of ink ejection nozzle arrangements in fluid communication with respective ink supply channel groups, each ink ejection nozzle arrangement comprising: a nozzle chamber structure mounted to the wafer assembly and defining a nozzle chamber for receiving ink from an ink supply channel and a nozzle rim through which ink in the nozzle chamber can be ejected; an anchor extending from the wafer assembly in a location external to the nozzle chamber; and an elongate thermal actuator mechanism extending from the anchor and into the nozzle chamber, the thermal actuator mechanism comprising an elongate arm which terminates in a free end within the nozzle chamber and a pair of layers of conductive material located on either side of the elongate arm, one of the layers being connected to a current supply so that, in use, the free end of the arm can be moved to eject ink in the nozzle chamber through the nozzle rim as a result of differential thermal expansion.