Inkjet printhead with nozzle layer defining etchant holes
View Patent ↗The current invention provides for an inkjet printhead for an inkjet printer. The inkjet printhead includes a wafer substrate defining an ink supply channel. Side wall portions extend away from one surface of the wafer substrate, and a nozzle layer supported on the side wall portions and extending parallel to said one surface of the wafer substrate. The nozzle layer and the side wall portions define an array of nozzle chambers for receiving ink. The nozzle layer defines ink ejection ports and etchant holes. The etchant holes are of sufficient diameter to retain ink in the nozzle chamber by surface tension. Each nozzle chamber has a thermal actuators cantilevered on the wafer substrate. The actuator partitions the nozzle chamber and has a heater layer which produces thermal expansion of said actuator upon activation.
1. An inkjet printhead for an inkjet printer, said inkjet printhead comprising:
a wafer substrate defining an ink supply channel therethrough;
side wall portions extending away from one surface of the wafer substrate;
a nozzle layer supported on the side wall portions and extending parallel to said one surface of the wafer substrate, the nozzle layer and the side wall portions defining an array of nozzle chambers for receiving ink, said nozzle layer defining ink ejection ports and etchant holes, the etchant holes being of sufficient diameter to retain ink in the nozzle chamber by surface tension; and
a plurality of thermal actuators cantilevered on the wafer substrate; one of the thermal actuator being positioned in each of the nozzle chambers respectively such that the thermal actuator partitions the nozzle chamber, the thermal actuator having a heater layer which produces thermal expansion of said thermal actuator upon activation.
2. The inkjet printhead of claim 1 , wherein the wafer substrate includes a CMOS drive circuitry layer connected to the heater layer for providing an electrical current to the heater layer.
3. The inkjet printhead of claim 2 , wherein the CMOS drive circuitry layer includes multi-level metal layers sandwiched between oxide layers.
4. The inkjet printhead of claim 1 , wherein the actuator includes a gold serpentine heater layer sandwiched between two polytetrafluoroethylene (PTFE) layers.
5. The inkjet printhead of claim 4 , wherein the PTFE layer of the actuator proximate the ink supply channel has a coefficient of thermal expansion of about 770×10 −6 .
6. The inkjet printhead of claim 4 , wherein the PTFE layer proximate the ink supply channel is configured to be hydrophobic.
7. The inkjet printhead of claim 4 , wherein the PTFE layer proximate the ink ejection port is configured to be hydrophilic.