A New Model to Predict Ink Transfer on Coated Paper in Multiple Nips

A model relating the ink transfer in multiple nips to the ink/paper setting rate is proposed. The model differs from previous work in that the effects of ink/paper interaction in multiple nips and printing speed are included. In addition, the model is based on physical properties of the ink and substrate that can be measured independently. The model is based on the idea of a filtercake on the paper surface during the process of ink setting. The thickness of free splitting film in a printing nip depends on the growth rate of the filtercake. Laboratory printing tests can be used to characterize the ink/paper setting rate. This model predicts the correct trends of the experimental data and agrees with experimental observations that a fast setting surface receives more ink than a slow setting surface. The model is important to predict ink density differences from point to point, related to variation in coating properties. Therefore, the occurrence of backtrap mottle may be predicted.