Research on micro heater efficiency for thermal inkjet head

Micro heaters for thermal inkjet print heads are investigated to estimate the effects of heater size and operating condition on its thermal efficiency. Tantalum Aluminum (TaAl) heaters, 0.15mum in thickness, are prepared on silicon oxide layer. Silicon nitride film of 0.4mum thickness covers the heater. Visualization technique is applied to observe bubbles in open pool condition. Volume and life time of bubble are measured from CCD images of plane and side views of the bubble generated at the heat flux range of 0.5similar to5.0GW/m(2). Thermal conduction simulation for the heater provides bubble nucleation pressure. Bubble work is calculated with Asai's pressure model(1) and the visualization results; bubble life time and volume. Then, thermal efficiency of the heater defined as the ratio of bubble work to the electric input energy can be estimated.