The Effects of Operating Parameters on Micro-Droplet Formation in a Piezoelectric Inkjet Printhead Using a Double Pulse Voltage Pattern

Abstract

The formation and ejection behavior of droplets created by a squeeze mode piezoelectric inkjet printing device using a double pulse voltage pattern are investigated in this study. Two types of fluid, de-ionized (DI) water and ethylene glycol, are used. The effects of operating frequency, positive voltage keeping time and pulse voltage magnitude on the volume and velocity of the droplets are discussed. The experimental results are consistent with the propagation theory of acoustic waves. The maximum allowable pulse frequencies in DI water and ethylene glycol are 2,000 and 22,700 Hz respectively. If the positive voltage keeping time equals the time required for the acoustic waves to propagate through the printhead, optimal ejection behavior is achieved. As the pulse voltage increases, both the velocity and volume of each droplet become larger.