Ink jet nozzle geometry selection by laser ablation of thin walls

A novel method of fabricating the channel ends of an ink jet printhead: lithographically fabricating channels in photopolymer having the channel end blocked by a thin layer of photopolymer; sandwiching the photopolymer between two parallel substrates, one of which has an actuator for each channel; dicing through the substrates on a line perpendicular to the channels and leaving the channels and solid wall at the end of the channels intact; optionally coating the diced face including the polymer wall blocking the channel ends with a hydrophobic material; and forming nozzles in the end of the channels by laser ablating through the polymer layer at the end of the channel. Forming the nozzles after dicing and the optional coating prevents contamination of the interior of the printhead. The nozzles can be recessed from the diced edges of the substrate. Photolithographic formation of the end of the channel insures an accurate distance is maintained between the nozzle and the actuator. Improved jetting stability, directionality of the ejected drops, and drop size result from this novel fabrication method.