Hybrid fluid jet drop generation

In a fluid jet head including a fluid input connected to a source of pressurized fluid, a plurality of nozzle orifices, a cavity communicating with said input and with said nozzle orifices to eject a stream of fluid from each said orifices, and a signal input connected to a perturbation signal source, the improvement comprising:

• a perturbation means connected to said signal input and mounted to both vibrate said nozzle orifices in an axial direction and vary the volume of said cavity in response to said perturbation signal, for perturbating the velocity of each said fluid stream to cause each said ejected stream to break into a serial stream of drops;
• said perturbation means comprising an electromechanical transducer for establishing a mechanical perturbation in response to said perturbation signal;
• said perturbation means additionally forms a wall of said cavity vibrated by said mechanical perturbation to vary the volume of said cavity;
• said nozzle orifices are located in another wall of said cavity and said wall is vibrated by said mechanically transmitted perturbation;
• a cavity plate forming said cavity and said nozzle orifice locating wall of said cavity;
• and
• a mounting block for clamping said electromechanical transducer between said block and said cavity plate;
• for mechanically transmitting said mechanical perturbation to said nozzle orifices.