Prediction of emulsification drop size in a printing nip

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. �