Development of the new thermal inkjet head on SOI wafer

A new thermal inkjet printer head on SOI wafer was proposed. It was composed of two rectangular heaters with same size. So we could call it T-jet (Twin jet). As it uses the back shooting mechanism, the ejected ink's direction is the opposite direction of the bubble generated. T-jet has a lot of merits. It has the advantage of being fabricated with one wafer and is easy to change the size of chamber, nozzle, restrictor and so on because of being manufactured on SOI wafer. The chamber was formed in its upper silicon whose thickness was 40 μm. The chamber's bottom layer was silicon dioxide of SOI wafer and two heaters were located underneath the chamber's ceiling. And the restrictor was made beside the chamber. Nozzle was molded by process of Ni plating. Ni was 30-μm thick. Nozzle ejection test was performed by printer head having 56 nozzles in two columns with 600 nozzle per inch and black ink. It was measured a drop velocity of 12 m/s, a drop volume of 30 pl, and a maximum firing frequency of 12 kHz for single nozzle ejection. Throwing out the ink drop in whole nozzles at the same time, it was observed that the uniformity of the drop velocity and volume was less than 4%.