Characterization of thermal inkjet droplets jitter

Abstract

Due to the randomness in the nucleation process of vapor bubbles and the instability of ink drop breakup in the thermal inkjet drop ejector, the drop velocity varies slightly from drop to drop, such a variation is called the jitter of the droplets. Droplet jitter causes variations in drop volume, satellite drop formation, and drop placement error on the receiving substrate, which limit the high accuracy printing application for thermal inkjet. Traditionally, a multiple-exposure method is used to photograph the droplets in flight, which is unable to measure jitters of every drop due to the low sampling rate. In this study, a laser-based high-speed flying drop measurement system is used to study the jitter. We tentatively propose a simple model to explain the cause of droplet jitter, which is related to the latency phenomenon, the randomness in droplet formation and the difference in droplets velocity. The jitter is recorded under different driving conditions and the distribution of jitter is analyzed. As a conclusion, the conditions for operation to achieve lower jitter are determined. Under certain driving conditions, the jitter can be reduced by 90%.