Effect of Fountain Solution on Ink Tack Development and Print Quality, 1999 Coating Conference Proceedings

Yang Xiang and Douglas W. Bousfield

Department of Chemical Engineering

University of Maine

Paper-ink interactions control the printing operation and the quality of final print. However, most previous work reports the results for pure inks and dry paper surfaces. The actual conditions of wetted surfaces and emulsified inks, as in the "real life" situation, are not well understood. This work is among the first to quantify the interaction of emulsified ink with dry and wetted substrates.

The objective of the current work is to examine the influence of fountain solution on ink tack development on coated paper and final print quality, using our Micro-Tackmeter and the a laboratory print tester. Plastic films, pure latex films, a “model” plastic pigment coating, and commercial grade coatings are used in this study. Preliminary results show that an emulsified ink has a faster tack development on all substrates compared to the pure ink. In addition, the emulsified ink gives a lower print density and print gloss than the pure ink. Plastic pigment coatings wetted with fountain solution, set ink more rapidly than the dry surface, but the ink setting on commercial coatings are insensitive to wetting. On the non-absorbent plastic film, the print surface of emulsified ink is rougher than that of the pure ink. However, on the model pigmented coating, finer ink splitting patterns are found on the print with emulsified ink. This result implies that the emulsified ink has a smaller filament size when splitting in the nip or a better film leveling property after leaving the nip. This may lead to higher print gloss.