Abstract: Apparatus for forming an array of liquid streams which break up into small uniformly sized and spaced droplets. A cover plate is sealed to a base plate having grooves sized and spaced according to a predetermined pattern to define a plurality of nozzles. Manifold means are provided to supply liquid under pressure to the nozzles thus formed. In a preferred embodiment for ink-jet applications the nozzles, or manifold branches supplying the nozzles, are of such a configuration as to electrically isolate the liquid flowing therethrough and separate electrodes are provided for each nozzle. This makes it possible to use a common charging electrode for the array while exercising separate control over the droplet-forming streams.