Continuous ink jet apparatus and method using a plurality of break-off times

Abstract

A continuous liquid drop emission apparatus is disclosed comprising a liquid drop emitter containing a positively pressurized liquid in flow communication with a plurality of nozzles formed in a common nozzle member for emitting a plurality of continuous streams of liquid. A jet stimulation apparatus is provided comprising a plurality of transducers corresponding to the plurality of nozzles and adapted to transfer energy to the liquid in corresponding flow communication with the plurality of nozzles sufficient to cause the break-off of the plurality of continuous streams of liquid at a plurality of predetermined break-off times into a plurality of streams of drops of predetermined volumes. Sensing apparatus is provided adapted to measure a characteristic value for each of the plurality of streams of drops of predetermined volumes; and control apparatus is adapted to provide a plurality of break-off time setting signals to the jet stimulation apparatus to cause the plurality of predetermined break-off times determined, at least, by the characteristic value of each of the plurality of streams of drops of predetermined volumes. Alternately, a sensing apparatus is used in an off-line calibration set-up and characteristic values are measured for the plurality of streams and stored in a stream memory that is included in the continuous liquid drop apparatus. The present inventions are also configured to provide a plurality of the break-off times for a plurality of liquid streams in a continuous liquid drop emission apparatus that is further adapted to inductively charge at least one drop in a each of a plurality of streams and having electric field deflection apparatus adapted to generate a Coulomb force on an inductively charged drop. Methods of operating a continuous liquid drop emission apparatus utilizing a plurality of predetermined break-off times are disclosed.