But adhesives can interact with and ruin inks. To get around this limitation and build a sturdier, more rugged printhead, engineers at PicoJet Inc., Portland, Oreg. (picojet.com), ultrasonically weld several stainless-steel plates together to form the PJ-N256 dropon-demand printhead. This design prevents ceramic piezoelectric material from entering the fluid channels and blocking nozzles.

Each nozzle has a piezoceramic actuator. Applying a voltage expands the actuator and it pushes down on a diaphragm plate forcing out ink droplets. Each independently addressable nozzle assembly can spit out 10,000 drops/sec at 6 to 8 m/sec. A complete printhead consists of 256 nozzles in a 16 16 array. It delivers 300-dpi resolutions and can be used for four-color printing on foam board, canvas, textiles, glass, metal, plastic and, of course, paper. The all-metal ink channel handles aggressive ink chemistries, including UV-curable, oil, water, solvent, hot wax, and conductive inks.