Image Quality and Surface Tension of Digital UV Curable Inks

Abstract

Surface tension of a digital ink can affect substrate wetting, print resolution and jet stability. Digital printing with UV curable inks is a dynamic process involving droplet formation/ejection, substrate wetting and UV cure, which occurs on the order of milliseconds. Dynamic surface tension (DST) measurements can provide information in 10 to 1000 millisecond timeframe. This paper will focus on the effect of surfactant type and concentration on print image quality. Surface tension difference between the substrate and ink was found to affect drop size and image quality. This difference for various substrates places constraints in providing good image quality with a single ink on all substrates. Information from DST measurements can be used to match ink and substrate surface tension. This helps an ink formulator to choose the optimum ink to provide the effective image quality to end user.