Patent ID: 7673976

Claim:
A continuous liquid drop emission apparatus 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 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; control apparatus 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, said break-off time setting signals determined, at least, by a characteristic value of each of the plurality of streams of drops of predetermined volumes; and sensing apparatus adapted to measure the characteristic value for each of the plurality of streams of drops of predetermined volumes, wherein pairs of drops in a stream of drops of predetermined volumes have an inter-drop time period characterized by an average value and a statistical deviation from the average value, and the characteristic value the stream of drops of predetermined volumes that is measured includes the statistical deviation in the inter-drop time period determined by differences in the measured times of flight for the pairs of drops.