Patent ID: 8919899

Claim:
An apparatus for direct printing of features on a surface using a hydrodynamically focused liquid jet consisting of a sacrificial sheath liquid and a core liquid, the apparatus comprising; a print head consisting of pressurized liquid reservoirs for the sheath and core liquids, a flow cell that forms an annular distribution of the sheath and core liquids, and an exit orifice from which an annular jet propagates for a distance of at least approximately five centimeters; a means for controlling the flow rates of the sheath and core liquids independently, so that the diameter of the filament of focused core liquid is approximately 0.10 to 0.75 times the diameter of the exit orifice; a heater assembly for the purpose of superheating the sheath liquid within the print head; a means to enable digital shuttering of the core liquid within the flow cell, while leaving the sheath flow uninterrupted; an external shutter that interrupts or deflects the annular jet or the sheath jet so that discreet features are produced.