The Influence of Ink Formulation and Paper Properties on Water-based Flexographic Ink Transfer

摘要

The printing of packaging material with flexographic methods continues to be a growing market. The need to obtain high quality images on various substrates is important. For various reasons, the interest to use water based inks is high. Some basic mechanisms about ink setting on paper surfaces are still not clear. Solution polymer inks and emulsion based inks are compared on various substrates. The ink transfer was characterized by ink density measurements. A mathematical model is developed that describes the transfer of ink and the setting within the nip. For some inks, the contact angle of the substrate influenced the transfer, but for other ink formulations there was a strong influence. These differences seem to be related back to the filtercake resistance of the inks in question. If the filtercake controls the absorption of ink vehicle into the substrate, then the contact angle of the substrate did not play a role. A new model is presented that predicts the dot gain for these inks.