Ink jet nozzle having an actuator mechanism comprised of multiple actuators
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. A series of radially positioned actuators are connected to the wafer substrate and extend radially inwardly towards the rim. Each actuator is configured so that a radially inner edge of each actuator is displaceable, with respect to the nozzle rim, into the chamber, upon actuation of the actuator and so that, upon such displacement, a pressure within the nozzle chamber is increased, resulting in the ejection of ink from the ejection port.
1. An ink jet nozzle arrangement comprising:
nozzle chamber which includes a wall defining an ink ejection port; and
a plurality of micro-electromechanical actuators that are connected to electronic drive circuitry and operatively arranged relative to said port, each actuator being configured so that, on receipt of an electrical signal from the drive circuitry, at least part of the actuators are displaced relative to said port causing ejection of ink from said nozzle chamber through said ink ejection port; 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.
2. The arrangement of claim 1 in which 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.
3. An ink jet nozzle arrangement of claim 1 wherein the actuators are arranged radially about the ejection port.
4. An ink jet nozzle arrangement of claim 1 wherein the actuators are arranged radially about the ejection port and extend radially inwards from a peripheral edge of the nozzle chamber.
5. An ink jet nozzle arrangement of claim 1 wherein at least part of each of the actuators bends into the nozzle chamber on receipt of the electrical signal.
6. A printing mechanism that includes at least one printhead chip as claimed in claim 5 .
7. An ink jet printhead chip comprising:
a substrate having electronic drive circuitry; and
plurality of nozzle arrangements positioned on the substrate, each nozzle arrangement comprising:
nozzle chamber walls and a roof wall that define a nozzle chamber and an ink ejection port in fluid communication with the nozzle chamber; and
plurality of micro-electromechanical actuators that are connected to the electronic drive circuitry, the actuators being operatively positioned with respect to the nozzle chamber and configured so that, on receipt of an electrical signal from the electronic drive circuitry, at least one part of the actuators, is displaced with respect to the ink ejection port to eject ink from the ink ejection port; 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 the actuator.
8. An ink jet printhead chip of claim 7 in which each resistive heating circuit is at least partially embedded in the actuating member that has 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.
9. An ink jet printhead chip of claim 7 wherein the actuators are arranged radially about the ejection port.
10. An ink jet printhead chip of claim 7 wherein the actuators are arranged radially about the ejection port and extend radially inwards from a peripheral edge of the nozzle chamber.
11. An ink jet printhead chip of claim 7 wherein at least part of each of the actuators bends into the nozzle chamber on receipt of the electrical signal.
12. An ink let 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
nozzle chamber walls and a roof wall that define a nozzle chamber and an ink ejection port in fluid communication with the nozzle chamber; and
a plurality of micro-electromechanical actuators arranged radially about the ejection port for connection to the electronic drive circuitry, the actuators being operatively positioned with respect to the nozzle chamber and configured so that, on receipt of an electrical signal from the electronic drive circuitry, the actuators, are displaced with respect to the ink ejection port to eject ink from the ink ejection port; 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 an electrical signal from the drive circuitry, the actuating member is subjected to differential expansion which results in movement of the actuating member and thus the actuator.
13. An ink jet printhead chip of claim 12 wherein the actuators are arranged radially about the ejection port and extend radially inwards from a peripheral edge of the nozzle chamber.
14. An ink jet printhead chip of claim 12 wherein at least part of each of the actuators bends into the nozzle chamber on receipt of the electrical signal.