Measurement of Complex Rheology and Jettability of Inkjet Inks

In any inkjet system, the ink goes through various physical and geometrical constraints that influence the flow dynamics and finally the jetting characteristics. The choice of solvents, binders, additives, and particles have significant influence on the complex dynamic properties of the fluids, jetting behavior, and reliability of apparently identical inks that have similar bulk properties. The complex dynamic properties of the ink become one of the key parameters that affect the whole ink jet process and jetting behavior. This has direct influence on printhead pumping capacity for drop ejection, in-flight jetting and breakup behavior, meniscus damping profile post-jetting, and ink channel re-filling capability. High-frequency rheological tools such as TriPAV and extensional rheometer TriMaster are capable of quantifying subtle differences in the complex rheology of inks at similar jetting timescale and geometry of inkjet system. Understanding the influence of these dynamic properties of inkjet inks help differentiate inks, formulate reliable high-viscosity inkjet inks, and speed up waveform development.