Drop-on-demand hybrid printing using a piezoelectric MEMS printhead at various waveforms, high voltages and jetting frequencies

In this paper, electrohydrodynamic jetting is investigated in order to print ultra-fine dots and lines in drop-on-demand (DOD) mode, using micro-electromechanical system-based printhead with a piezoelectric actuator. In such hybrid system, jetting ultra-fine droplets in DOD mode, without applying an extremely high-voltage pulse, is possible as the meniscus is first disturbed by a piezoelectric actuator and the droplet is ejected by the applied electric field. As the amplitude of the drive waveform of the piezoelectric actuator is varied, droplets with volumes of 3.4 to 46.8 pL are realized. As the amplitude of the electric field is increased, the ejected droplets lengthen and at 8 kV, thin elliptical dots are printed. Although changing the jetting frequency from 0.1 to 2.0 kHz resulted in volume reduction from 9.4 pL down to 2.9 pL, the DOD characteristic is well maintained throughout. Such hybrid jetting characteristics enable the generation of diverse patterns in the printed electronics area.