Mitsuo Tsuzuki

Improved Drop Ejection Characteristics through Use of Micro-Valves in Ink Jet Head

A new pressure-pulsed ink jet head with two micro-valves has been developed. This ink head gives a wide frequency response and produces little fluctuation in the velocity of the ink droplets. Drop ejection has been analyzed theoretically using a physical model, including meniscus motion in a nozzle, pressure generation by a piezoelectric transducer, and micro-valve operation. It is found that damped oscillation in the ink flow is produced by both the elastic energy of the piezoelectric transducer and the surface tension of the nozzle meniscus. This oscillation causes a deterioration in the characteristics of drop velocity versus operational frequency. However, the microvalves described here make it possible to prevent this damped oscillation, as well as to eliminate the capillarity dependency of the ink supply.

Dynamic Analysis of Vapor Bubble in Liquid Using Acoustic Emission Measurement

Acoustic source wave analysis was carried out to examine quantitatively the dynamic motion of a vapor bubble generated on a superheated surface in a liquid. In this analysis, the response function for the transmission medium and the transducer was taken into account, and the source wave was obtained in terms of the pressure-time function through FFT and IFFT. The relationship between the acoustic energy of the source wave and the characteristics of the ink droplet ejection was evaluated for the purpose of applying high pressure vapor bubbles to use in thermal ink jet technology.