Microelectromechanical fluid ejection device
View Patent ↗In order to provide a very high printing resolution a microelectromechanical fluid ejection device is provided. The device includes a plurality of thermal fluid ejection assemblies formed upon a common wafer substrate by means of integrated circuit fabrication processes. Each of the assemblies includes a nozzle chamber covered by a roof into which an ink ejection port is formed. An electrically activated thermal actuator mechanism is formed on the wafer having a free end that extends into the nozzle chamber in order to cause ejection of ink contained in the chamber through the port during use. Heat sinks are provided on the thermal actuator mechanism to avoid performance failure due to overheating.
1. A microelectromechanical fluid ejection device including a plurality of thermal fluid ejection assemblies formed upon a common wafer substrate, each of said assemblies including:
a nozzle chamber formed in the wafer substrate;
a roof located over the nozzle chamber into which an ink ejection port is formed; and
an electrically activated thermal actuator mechanism including a fixed end fast with the wafer substrate and a free end extending into the nozzle chamber, the thermal actuator mechanism including one or more heat sinks.
2. A fluid ejection device according to claim 1 , wherein the fixed end comprises an end of an actuating portion of the actuator mechanism that is fast with an anchoring member mounted on the wafer substrate.
3. A fluid ejection device according to claim 2 , wherein the free end comprises a paddle connected to the actuating portion.
4. A fluid ejection device according to claim 3 , wherein the actuating portion comprises first and second opposed activating arms.
5. A fluid ejection device according to claim 4 , wherein the first activating arm defines a resistive heating circuit that is connected to a driving circuit.
6. A fluid ejection device according to claim 4 , wherein the driving circuit comprises an electronic circuit layer disposed over the wafer substrate.
7. A fluid ejection device according to claim 6 , wherein the electronic circuit layer comprises a CMOS layer.
8. A printhead including a fluid ejection device according to claim 7 .
9. A printer including a printhead according to claim 8 .
10. A fluid ejection device according to claim 6 , wherein the driving circuit is arranged to generate a high frequency electrical potential to cause oscillation of the paddle in use.
11. A fluid ejection device according to claim 4 , wherein the first and second activating arms are of a resiliently flexible material.
12. A fluid ejection device according to claim 1 , wherein the heat sink is mounted upon the first activating arm.
13. A fluid ejection device according to claim 12 , wherein the heat sink is mounted towards the middle of the first activating arm.
14. A printhead including a fluid ejection device according to claim 1 .
15. A printer including a printhead according to claim 14 .