Micro-electromechanical nozzle arrangement with a roof structure for minimizing wicking
View Patent ↗Provided is a micro-electromechanical nozzle arrangement for an inkjet printhead. The arrangement includes a substrate defining an inverted pyramidal ink chamber with a vertex thereof terminating at an ink supply channel through the substrate, said substrate having a layer of CMOS drive circuitry. The arrangements also includes a roof structure connected to the drive circuitry layer and covering the ink chamber, the roof structure defining a fluid ejection nozzle rim above said chamber in addition to ink flow guide rails to minimize wicking along the nozzle rim according to surface tension effects of ink in the chamber. Also included is a plurality of actuators displaceable with respect to, and radially spaced about, the nozzle rim, and in between, the guide rails. Each actuator has a serpentine heater element configured to thermally expand upon receiving current from the drive circuitry thereby moving said actuators into the chamber operatively increasing a fluid pressure inside the chamber to eject a drop of ink via the ejection nozzle.
1. A micro-electromechanical nozzle arrangement for an inkjet printhead, said arrangement comprising:
a substrate defining an inverted pyramidal ink chamber with a vertex thereof terminating at an ink supply channel through the substrate, said substrate having a layer of CMOS drive circuitry;
a roof structure connected to the drive circuitry layer and covering the ink chamber, the roof structure defining a fluid ejection nozzle rim above said chamber in addition to ink flow guide rails to minimize wicking along the nozzle rim according to surface tension effects of ink in the chamber; and
a plurality of actuators fast with and displaceable with respect to the roof structure, the actuators radially spaced about the nozzle rim in between the guide rails, each actuator having a serpentine heater element configured to expand thermally upon receiving current from the drive circuitry thereby moving said actuators into the chamber operatively increasing a fluid pressure inside the chamber to eject a drop of ink via the ejection nozzle.
2. The nozzle arrangement of claim 1 , wherein each actuator is cantilevered to a heater element in a bendable manner.
3. The nozzle arrangement of claim 1 , wherein the actuators include a polytetrafluoroethylene (PTFE) layer with the heater element made from copper.
4. The nozzle arrangement of claim 1 , wherein the ink supply channel is the result of a deep silicon back etch of the substrate utilizing a plasma etcher.
5. The nozzle arrangement of claim 1 , having a central arm which includes both metal and PTFE portions to provide structural support for the actuators.
6. The nozzle arrangement of claim 1 , wherein the serpentine heater element is of gold.