ACOUSTIC FLUID JET METHOD AND SYSTEM FOR EJECTING DIPOLAR GRAINS

摘要

A method and apparatus (10) for ejection of nanometer length-scale, dipolar grains (16) from a host liquid (14), such as a dilute ferrofluid with grains suspended in water (e.g., gamma -Fe2O3). In a preferred embodiment, the host liquid is subjected to a strong, homogeneous magnetic field (22) directed perpendicular to an exit surface of the liquid, thereby causing columns of dipolar grains (16) extending parallel to the field direction to form. An acoustic impulse is initiated at the base of the container (12) and propogates as a non-dispersive solitary wave pulse with sufficient energy to overcome surface tension and eject a ferrofluid grain nearest to the exit surface of the liquid. In another preferred embodiment, a rapid series of acoustic impulses constructively interfere with each other to eject a plurality of grains nearest the exit surface. The method and apparatus of the invention are useful in the design of a nozzle-free ink-jet printer (10) of unparalleled resolution.