Abstract: Method and apparatus for generating a plurality of parallel droplet streams in a coating apparatus, such as an ink jet printing device, in which the streams break into droplets from fluid filaments at a uniform distance from issuing orifices. The streams issue from a pressurized chamber in which an elastic bending member is repetitively flexed by a plurality of parallel bending elements operated simultaneously to produce uniform bending throughout the effective length of said member to produce successive pressure disturbances within the supply chamber and induce varicosities of the same size and frequency in the issuing streams. This arrangement is able to enhance printing quality in an ink jet recorder by permitting maintenance of proper phase relationship between droplet formation and charging voltage.