Printhead chip that incorporates pivotal micro-mechanical ink ejecting mechanisms

1. A printhead integrated circuit which comprises

a substrate that incorporates drive circuitry and defines ink inlet channels;

nozzle chamber structures positioned on the substrate, each nozzle chamber structure defining a nozzle chamber in fluid communication with a respective ink inlet channel and an ink ejection port in fluid communication with the nozzle chamber;

cantilevered ink ejecting mechanisms pivotally displaceable with respect to the substrate to eject drops of ink from the ink ejection ports, such that during use, the ink flow through the ink inlet channel into each respective nozzle chamber is in the same direction as the drops ejected through the ink ejection port; and

actuators connected to the drive circuitry for individual actuation, each actuator including a force transmitting portion that is substantially linearly displaceable upon receipt of a signal from the drive circuitry and is connected to a respective cantilevered ink ejecting mechanism to displace the cantilevered ink ejecting mechanism pivotally with respect to the substrate.

2. A printhead integrated circuit as claimed in claim 1 , in which each nozzle chamber structure includes nozzle chamber walls and a roof that spans the walls and defines the ink ejection port.

3. A printhead integrated circuit as claimed in claim 2 , in which the ink ejecting mechanisms include a plurality of elongate ink ejecting members positioned in respective nozzle chambers and reciprocally pivotal with respect to the substrate so that free ends of the ink ejecting members are displaced towards and away from the ink ejection ports to eject ink from the ink ejection ports.

4. A printhead integrated circuit as claimed in claim 3 , in which the ink ejecting mechanisms include in micro-mechanical pivot structures pivotally connected to respective nozzle chamber structures and interposed between respective force transmitting portions and opposite ends of associated ink ejecting members such that displacement of the force transmitting portions results in said pivotal displacement of respective ink ejecting members.

5. A printhead integrated circuit as claimed in claim 4 , in which the pivot structures are pivotally mounted with respect to the roofs and are positioned in the walls of the nozzle chamber structures.

6. A printhead integrated circuit as claimed in claim 1 , in which the nozzle chamber structures incorporate the ink ejecting mechanisms such that the ink ejecting mechanisms are pivotally displaceable towards and away from the substrate to decrease and increase the nozzle chambers' volume so that ink drops are ejected from the ink ejection ports.

7. A printhead integrated circuit as claimed in claim 1 , in which each actuator includes an anchor arrangement that is fast with the substrata and extends from the substrate, each force transmitting portion being a thermal expansion member extending from the substrate to be spaced from the substrate and defining a heating circuit electrically connected to the drive circuitry to receive an electrical signal from the drive circuitry so that the expansion member expands and subsequently contracts.

8. A printhead integrated circuit as claimed in claim 1 , in which the ink inlet channels are generally aligned with the respective ink ejection ports.