Patent ID: 7658478

Claim:
An apparatus for forming fluid droplets comprising: a nozzle channel; a pressurized source of a non-conductive fluid in fluid communication with the nozzle channel, the pressurized source being operable to form a jet of the non-conductive fluid through the nozzle channel; and a stimulation electrode for forming fluid droplets, at least one portion of the stimulation electrode being electrically conductive and contacting with a portion of the non-conductive fluid jet, the at least one electrically conductive portion of the stimulation electrode being operable to transfer an electrical charge to a region of the portion of the non-conductive fluid jet, wherein the electrical charge stimulates the non-conductive fluid jet to form a non-conductive fluid droplet, and wherein a resistivity of the non-conductive fluid required for droplet stimulation is determined by requiring that a discharge time constant T RC of transferred charges be of the same duration or longer than a droplet time-to-break-off interval T b (T RC ≧T b ).