Herman A. Hermanson

Testing unpackaged thermal ink-jet printing devices

There are stages in the refinement of new imaging processes where the use of unique test equipment and study tools is required to isolate problems related to performance and fabrication steps. A juncture had been reached in the Xerox thermal ink jet program where an evaluation of the printing device for both electrical function and print quality prior to final packaging was required. Nondestructive testing is necessary so that these printing devices can be tested repeatedly and subsequently packaged by mounting them onto a substrate with appropriate circuit boards, wire bonds, and ink manifolds to form finished thermal ink jet printheads. This paper describes test equipment which has been designed to electrically test, print test, and fully evaluate imaging properties of unpackaged thermal ink jet printing devices. The use of this test equipment and related testing procedures has accelerated process development times significantly and is playing a key role in quality control functions in the product manufacturing environment. Test equipment, techniques and results are discussed.