An electrostatic drop-on-demand micro droplet ejector with a pole type nozzle

This paper present a novel electrostatic drop-on-demand micro jetting device featured by a MEMS fabricated nozzle with a conductive pole inside, referred to here as a pole type nozzle. The electric voltage signal applied to the ring shaped upper electrode plate, against the pole as the ground, allows a micro-dripping ejection of droplet to take place: That is, a tiny droplet is taken away from the peak of the mountain shaped liquid meniscus formed at the nozzle orifice. It is verified experimentally that the use of the pole type nozzle allows a stable and sustainable micro-dripping mode of droplet ejection for a wider range of applied voltages and of liquid viscosities than a hole type nozzle, such as a conventional spray nozzle. This demonstrates a feasibility of electrostatic drop-on-demand micro dripping droplet jetting as a disruptive alternative to conventional print heads.