Wet trapping method and apparatus for low viscosity radiation cured print

A method of printing ink upon a continuous substrate using a printing apparatus comprising the steps of:

• (a) feeding a continuous substrate around a central impression cylinder that rotates so as to successively pass the substrate through at least one face roll and a plurality of inking stations;
• (b) heating ink located at each inking station to a first predetermined temperature, said predetermined temperature being higher than a second predetermined temperature of said central impression cylinder of said substrate wherein the viscosity of said ink is dropped low enough so that said ink will be transferred to said substrate;
• (c) applying a first ink from a first inking station to the substrate wherein the temperature of the first ink decreases and the viscosity increases as the first ink is pulled off a first printing plate in the direction of the substrate;
• (d) applying an intermediate ink from an intermediate inking station to the substrate wherein previously applied ink on the substrate has a lower temperature and a higher viscosity than said intermediate ink, causing said previously applied ink to pull said intermediate ink off an intermediate printing plate in the direction of the substrate;
• (e) repeating step (d) at each one of the remaining of said plurality of inking stations;
• (f) curing the inked substrate which has passed through said plurality of inking stations at a curing station.