LIQUID EJECTION SYSTEM INCLUDING DROP VELOCITY MODULATION

摘要

A continuous liquid ejection system includes a liquid chamber in fluidic communication with a nozzle. The liquid chamber contains liquid under pressure sufficient to eject a liquid jet through the nozzle. A drop formation device is associated with the liquid jet and is actuatable to produce a modulation in the liquid jet that cause portions of the liquid jet to break off into a series of drop pairs traveling along a path. Each drop pair is separated in time on average by a drop pair period. Each drop pair includes a first drop and a second drop. A charging device includes a charge electrode associated with the liquid jet and a source of varying electrical potential between the charge electrode and the liquid jet. The source of varying electrical potential provides a waveform that includes a period that is equal to the drop pair period. The waveform also includes a first distinct voltage state and a second distinct voltage state. The charging device is synchronized with the drop formation device to produce a first charge state on the first drop and to produce a second charge state on the second drop. A drop velocity modulation device varies a relative velocity of a first drop and a second drop of a selected drop pair to control whether the first drop and the second drop of the selected drop pair combine with each other to form a combined drop. The combined drop has a third charge state. A deflection device causes the first drop having the first charge state to travel along a first path, causes the second drop having the second charge state to travel along a second path, and causes the combined drop having the third charge state to travel along a third path.