Abstract

The fountain solution balance on the press is an important issue in terms of operation and quality of the printed product. Fountain solution is emulsified into the ink during the printing process. While a number publications reporting the amount of fountain solution that is emulsified for various conditions have been published, less is understood with regard to the size of the fountain solution drops.

In this study, a known amount of fountain solution is applied to a rotating ink film. The rheology of the inks is characterized with a controlled stress rheometer. The size of the fountain solution drops is characterized via light microscope images. A finite element based model is used to predict the drop breakup in a shear field and the shear flow in the printing nip. The shear rates generated in the nip are used to predict the size of drops that would be generated. The model results are compared to the experiments.