Ink jet nozzle with multiple actuators for reducing chamber volume
View Patent ↗A nozzle arrangement for an ink jet printhead includes a wafer substrate having a nozzle chamber defined therein. The nozzle arrangement has a nozzle chamber wall that defines an ink ejection port and a rim about the ink ejection port. An array of actuators connected to the wafer substrate and configured so that an edge of each actuator is displaceable, into the chamber, upon actuation of the actuator. This displacement reduces the volume within the nozzle, resulting in the ejection of ink from the ejection port.
1. An inkjet nozzle arrangement comprising:
a nozzle chamber for holding a volume of ink, the chamber comprising a wall with an ink ejection port; and
a plurality of micro-electromechanical actuators arranged in the wall on the same plane as the ink ejection port and connected to electronic drive circuitry; such that,
the actuators reduce the volume of the nozzle chamber to eject ink through the port in response to an electrical signal from the drive circuitry.
2. An inkjet nozzle arrangement according to claim 1 wherein the actuators deform the wall towards the interior of the chamber to reduce the volume.
3. An inkjet nozzle arrangement according to claim 2 wherein the actuators expand in response to the electrical signal from the drive circuitry and are arranged in opposing pairs such that the actuators in each pair expand towards each other to deform the wall.
4. An inkjet nozzle arrangement according to claim 3 wherein each actuator comprises
an actuating member of a material that expands when heated; and
a heating circuit that is connected to the electronic drive circuitry and arranged with respect to the actuating member so that when the heating circuit receives said electrical signal from the electronic drive circuitry, the actuating member is subjected to differential expansion which results in movement of the actuating member and thus part of the actuator.
5. An inkjet nozzle arrangement according to claim 4 wherein each resistive heating circuit is at least partially embedded in the actuating member, the actuating member having a higher co-efficient of thermal expansion than the heating circuit, the heating circuit being arranged so that the actuating member is subjected to said differential expansion when the heating circuit receives the electrical signal.
6. An inkjet nozzle arrangement according to claim 1 wherein the actuators are arranged radially about the ejection port.
7. An inkjet nozzle arrangement according to claim 1 wherein the actuators are arranged radially about the ejection port and extend radially inwards from a peripheral edge of the nozzle chamber.
8. An inkjet nozzle arrangement according to claim 1 wherein at least part of each of the actuators bends into the nozzle chamber on receipt of the electrical signal.
9. An ink jet printhead chip comprising:
a substrate having electronic drive circuitry; and
a plurality of nozzle arrangements positioned on the substrate, each nozzle arrangement comprising:
a nozzle chamber for holding a volume of ink, the chamber comprising a wall with an ink ejection port; and
a plurality of micro-electromechanical actuators arranged in the wall on the same plane as the ink ejection port and connected to the electronic drive circuitry; such that, the actuators reduce the volume of the nozzle chamber to eject ink through the port in response to an electrical signal from the drive circuitry.
10. An ink jet printhead chip that comprises
a substrate that incorporates electronic drive circuitry; and
a plurality of nozzle arrangements positioned on the substrate, each nozzle arrangement comprising
a nozzle chamber for holding a volume of ink, the chamber comprising a wall with an ink ejection port; and
a plurality of micro-electromechanical actuators arranged in the wall on the same plane as the ink ejection port and connected to the electronic drive circuitry;
such that, the actuators reduce the volume of the nozzle chamber to eject ink through the port in response to an electrical signal from the drive circuitry.