AIR ASSISTED INK JET HEAD WITH PROJECTING INTERNAL INK DROP-FORMING ORIFICE OUTLET

摘要

: An air assisted drop-on-demand ink jet head has an ink chamber with an ink drop-forming orifice outlet from which ink drops are generated in response to pressure waves caused by a piezoelectric crystal. The ink drops are carried by air outwardly through an external orifice and toward printing medium. The internal orifice outlet is centered in a projecting structure which extends toward the external orifice. In one form, the projection is of a frustoconical or mesa-like shape. Air flowing past the top of the projection prevents ink from wetting anything but the top of the projection, resulting in highly uniform ink drop formation with a single uniform dot being produced on the printing medium in response to each pressure wave.