Nozzle assembly with heat deflected actuator
View Patent ↗A nozzle assembly is provided for ejecting ink. The nozzle assembly includes a substrate incorporating drive circuitry. An actuator support extends from the substrate. An actuator arm extends from the actuator support and includes a heater which is coupled to the drive circuitry. A nozzle extends from the substrate at a spaced apart location from the actuator support and the heater. The nozzle defines an ink chamber in fluid communication with: an ink supply, an ink ejection port in fluid communication with the nozzle chamber, and a slot through which the actuator arm extends and terminates in a free end within the ink chamber. Responsive to the heater receiving an electrical signal from the drive circuitry, the free end of the actuator arm is displaced in the ink chamber to eject ink contained therein through the ink ejection port.
1. A nozzle assembly for ejecting ink, the nozzle assembly comprising:
a substrate incorporating drive circuitry;
an actuator support extending from the substrate;
an actuator arm extending from the actuator support and having a heater element which is coupled to the drive circuitry and is configured to experience deflection when the heater element receives an electrical signal from the drive circuitry; and
a nozzle chamber structure extending from the substrate and spaced from the actuator support and the heater; the nozzle chamber structure defining a nozzle chamber in fluid communication with an ink supply, an ink ejection port in fluid communication with the nozzle chamber, and a slot through which the actuator arm extends and terminates in a free end within the nozzle chamber, such that, when the heater element receives the electrical signal from the drive circuitry, the free end of the actuator arm is displaced in the ink chamber as a result of the deflection to eject ink through the ink ejection port.
2. A nozzle assembly as claimed in claim 1 , wherein the actuator arm has two adjacent layers, each having different thermal expansion characteristics, with one of the layers defining the heater element.
3. A nozzle assembly as claimed in claim 2 , wherein one of the layers is of a material having a coefficient of thermal expansion that is less that that of the other layer defining the heater element with the heater element layer being positioned intermediate the former layer and the substrate so that the actuator arm bends away from the substrate when the electrical signal is supplied to the heater element.
4. A nozzle assembly as claimed in claim 2 , wherein only the heater element layer is coupled to the drive circuitry.
5. A nozzle assembly as claimed in claim 1 , wherein the nozzle comprises a cylindrical wall through which the actuator arm extends, and roof wall on the cylindrical wall defining the ink ejection port.
6. A nozzle assembly as claimed in claim 5 , wherein the roof wall defines a raised rim which bounds the ink ejection port.
7. A nozzle assembly as claimed in claim 1 , wherein the free end of the actuator arm defines a paddle.
8. A nozzle assembly as claimed in claim 1 , wherein the actuator support comprises a support post.