Relationship Between Ink Mileage and Ink Transfer

Ink mileage or saturation curves relate the optical density of a print to thickness of the ink on the substrate. Ink transfer curves indicate the fraction of ink being transferred from a blanket or plate to the substrate. These two factors play an important role in determining print quality. They are closely related to each other but generally discussed in the literature as separate issues. Several inks were printed on a Prufbau Printability Tester under various conditions of printing speed and printing force. Existing models were used to fit the experimental data, from which parameters characterizing ink transfer and ink mileage were evaluated. These results show that both printing force and printing speed have, as expected, tremendous impact on ink transfer behavior. Several inks were printed on a Prufbau Printability Tester under various conditions of printing speed and printing force. Existing models were used to fit the experimental data, from which parameters characterizing ink transfer and ink mileage were evaluated. These results show that both printing force and printing speed have, as expected, tremendous impact on ink transfer behavior. It is reported in the literature that either printing speed or printing force may effect the characteristics of saturation curves. It was found in this work that the effect of the printing conditions on the saturation curve is minimal. It is a logical conclusion that the optical density of a printed image is primarily determined by thickness of the ink on the substrate rather than by how the ink is placed there. However, the change in printing conditions will alter the optical density of printed images because it changes the amount of ink being transferred to the substrate. This infers that when the printing conditions change, the ink input should be regulated accordingly in order to maintain a consistent optical density of the image.