ERF Inkjet System Controlled by AC Electric Field

Abstract

Equivalent viscosity of Electro-rheological fluid (ERF) increases extremely when an electric field is applied across the fluid. ERF has a dielectric oily liquid base in which fine solid particles are suspended with small amount of surface active agents to prevent gravitational settling. A jet of this ERF is produced by forcing ink under high pressure if no electric field is applied across the fluid. When the electric field is applied, the ERF ink is not ejected from the nozzle because of its increased viscosity. Therefore, droplets generation of this ink can be controlled electrically. High printing quality and light fitness are expected to this type of DOD inkjet system, because the composition of ERF is similar to that of printing ink. We showed AC electric fields is preferable to control droplet ejection of the ERF ink jet system experimentally. When 500 Hz AC square voltage wave form is used, the maximum droplet generation rate obtained is about100 dps.