Multiple Dot Size Fluidics for Phase Change Piezoelectric Ink Jets

Ink jet waveform design is a challenge requiring knowledge of ink jet internal dynamics as well as surface dynamics of the aperture and mensicus. Waveforms generally are designed to excite the main driving frequency of the jet, while reducing energy at undesirable resonance frequencies, in order to reliably produce a single drop size. By exciting higher order modes of surface oscillation, drops of several sizes have been produced. Fundamental analysis, computational fluid dynamics simulations and laboratory experimentation have been used to provide a better understanding and demonstration of the drop size modulation process. Application of multiple drop size modulation includes variable resolution and gray scaling printing.