Patent ID: 7950771
Filing Date: 2011-05-31
Classification: B41J

Abstract:
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; a thermal actuator mechanism for ejecting ink from the chamber via the ejection port, the thermal actuator mechanism including 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; and drive circuitry for supplying the thermal actuator mechanism with a drive current, the drive circuitry being operable in a first and second operative mode, wherein in the first operative mode, the drive circuitry supplies current to the thermal actuator mechanism sufficient to cause the thermal actuator mechanism to bend to a degree whereby ink is expelled from the ink ejection port, and in the second operative mode, the drive circuitry supplies current to the thermal actuator mechanism insufficient to cause ink the thermal actuator mechanism to bend to such degree whereby ink is expelled from the ink ejection port.