| 摘要 |
PROBLEM TO BE SOLVED: To provide a thermal ink jet head comprising heating elements generating uniform bubbles and insusceptible to cavitation damage. SOLUTION: Heating elements 22 connected with a common electrode 18 and an individual electrode 21 and supplied with a heating pulse are formed under an orifice plate on which orifices (ink ejection nozzles) 32 are formed. The heating element 22 is obtained by shaping a film of Ta-Si-O, or the like, formed by thin film technology into a square by photolithography and making a circular excavated part 33 in the center. Assuming the diameter of the excavated part 33 is D, a relation '5μm<=D<=orifice diameter' is satisfied. When such a relation is set between the orifice and the excavated part of the heating element, a uniform bubble is generated and a uniform ink drop can be ejected and the heating element is insusceptible to cavitation damage.
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