Addressable electrohydrodynamic jetting via tuning the potential drop of liquid within the printhead

Abstract

Electrohydrodynamic (EHD) jetting is a promising technique with ultra-high resolution, broad compatibility with various inks, and tunable printing modes. However, it suffers from poor efficiency, which urgently calls for an addressable multi-nozzle printhead. Unlike traditional EHD printing which treats the liquid inside the printhead as an equal potential body, this work has proposed to realize addressable jetting by tuning the potential drop between the non-triggered nozzles (connected to a resistor and then grounded) and the triggered nozzles (connected to a high-voltage) through voltage division principle. We present an equivalent circuit model to predict the potential drop within the printhead, which largely depends on the liquid conductivity, channel character, and external auxiliary resistors, and these results match well with experiments and simulations. Besides, we further investigate the jet deflection behavior of the printhead, finding that 1.5 < H/dn < 3 (the ratio of printing height to the nozzle diameter) and 0.6 < k < 0.8 (the ratio of the non-triggered nozzles to the triggered nozzles) are preferred working area for addressable and precise EHD printing. This addressable design does not need a complex extractor underneath the nozzle, which is promising for future high-density and large-scale EHD printheads.