Drop-on-demand liquid emission using asymmetrical electrostatic device

摘要

A liquid emission device (10) includes a chamber (30) having a nozzle orifice (22). Separately addressable dual electrodes (28, 36) are positioned on opposite sides of a central electrode (38). The three electrodes are aligned with the nozzle orifice. A rigid electrically insulating coupler (40) connects the two addressable electrodes. To eject a drop, an electrostatic charge is applied to the addressable electrode (28) nearest to the nozzle orifice, which pulls that electrode away from the orifice, drawing liquid into the expanding chamber. The other addressable electrode (36) moves in conjunction, storing potential energy in the system. Subsequently the addressable electrode nearest to the nozzle is de-energized and the other addressable electrode is energized, causing the other electrode to be pulled toward the central electrode in conjunction with the release of the stored elastic potential energy. This action pressurizes the liquid in the chamber behind the nozzle orifice, causing a drop to be ejected from the nozzle orifice.