OVERSIZED NOZZLE OPENINGS ON THERMAL INK JET PRINTHEADS
Original Publication Date: 1996-Feb-29
Included in the Prior Art Database: 2004-Apr-07
Xerox Disclosure Journal
Disclosed is an improved thermal ink jet ( T.I.J. ) printhead comprising a conventional printhead modified with additional large channels located on the printhead die, and preferrably at the ends of the printhead die for the purpose of facilitating purging gas bubbles from the printhead which collect in the ink reservoir and near the entrance to the drop generating channel zones. In conventional thermal ink jet prinheads a long standing problem is the formation and trapping of gas or air bubbles in the printhead die, particularly at the ends of the die because of lower firing frequency and or latent heat considerations. The trapped bubbles can produce partial or complete omission print defects known as "dropout" on the printed ink image. A solution to the bubble formation and purge problem comprises fabricating ink jet dies with enlarged or oversized nozzle or muzzle openings which have an opening area of from about 10 to 100 percent larger than the nozzle channel itself. Fabrication can be accomplished by minor modifications of existing methods in accordance with the present disclosure. The enlarged or oversized nozzle openings are particularly useful with very small sized nozzle channels, for example, nozzles used to produce resolutions on the order of 600 spi or greater. In a related embodiment, the improved printhead includes a maintenance station with oversized nozzles which serve to prime the oversized nozzle openings on the printhead. The improved printhead is preferrably used in conjunction with partial printhead arrays or staggered printhead arrays, and can optionally be effective without a heating element present.