Characterization of Inkjet Inks by Ultrasonic Viscoelastic Measurements

Abstract

The effect of viscoelasticity on ink ejection from inkjet heads has been attracting attention recently. It is expected that the pressure propagation inside the head and the deformation speed and frequency during ejection are large, but there are no commercially available viscoelasticity measuring devices that can evaluate ink under these conditions. On the other hand, viscoelasticity measuring methods using pulsed ultrasound can evaluate bulk physical properties and sample surface properties at megahertz high frequencies. Here, we have demonstrated that it is possible to distinguish between samples of different manufacturers and compositions for commercially available inkjet inks with small viscosity terms, which was previously considered difficult to achieve with conventional methods. Unlike actual machine evaluation, the high-frequency viscoelasticity measuring method is simple and is therefore expected to accurately obtain ink physical properties, and therefore to provide useful parameters for inkjet ejection analysis.