In an ink jet recording device having a print head wherein an expanding bubble formed in ink ejects an ink droplet from an orifice, a method for testing wafers on which a large number of print heads are formed is provided wherein the head is filled with pure water, water droplets of the pure water is...http://www.google.com.au/patents/US5621524?utm_source=gb-gplus-sharePatent US5621524 - Method for testing ink-jet recording heads
