Summary

With IFRA Special Report 3.12 ("Which Shortcomings still exist in Anilox Offset?") we have shown where research and development has still to fill certain gaps to make this inking method an efficient means which fulfills all requirements of a daily newspaper production. One of these gaps we found out was that special inks had to be developed and selected to avoid excessive emulsification with the damping water. The computer simulations had given indications that ink refreshing systems like used in some Japanese presses might have a positive influence on that. Thus a second project was started in which eight different inks from four different suppliers were tested in view to their emulsification behaviour and with a simulated refreshing system. This report informs about the outcome of these tests, in the laboratory, in pilot scale printing trials and full scale printing trials in the field. In short it was proven that a stable ink/water balance in keyless offset systems requires an ink of low elasticity, high initial viscosity, moderate water take-up and little temperature dependence. Refreshing allows for higher water take-up, needs more energy and inkers may grow longer. In a third project which we are running this year we will look into the quality potentials of the new inking method in four colour printing in comparison to conventional inking and its effect on the economics of a newspaper printing plant. This information package may serve our members in their decision making process when new presses have to be ordered.