Printing of radiation curable inks into a radiation curable liquid layer
View Patent ↗A printing process is disclosed for ink-jet printing a radiation curable image on a substrate ( 14 ). First a radiation curable liquid layer ( 12 ) is provided on at least a portion of the substrate ( 14 ). Radiation curable ink-jet ink droplets ( 10 ) are jetted into the radiation curable liquid layer ( 12 ) and the radiation curable liquid layer ( 12 ) containing the radiation curable ink-jet ink droplets ( 13 ) is then cured. The resolution of the radiation curable image is controlled by uniformly adjusting the thickness of the liquid layer ( 12 ) for the dotsize of the radiation curable ink-jet ink jetted onto the cured layer.
1. A printing process for ink-jet printing a radiation curable image on a substrate comprising the steps of:
a) applying a radiation curable liquid layer of a uniform thickness on at least a portion of said substrate and in an area intended to be imaged with radiation curable ink-jet ink;
b) jetting a first radiation curable ink-jet ink droplet into said radiation curable liquid layer;
c) curing said radiation curable liquid layer containing said radiation curable ink-jet ink droplet; and
d) jetting a second radiation curable ink-jet ink droplet onto said cured layer of step c),
wherein the thickness of said radiation curable liquid layer is adjusted uniformly in order to control the resolution of said radiation curable image such that the dotsizes of said first and second radiation curable ink-jet inks do not differ by more than 10% in diameter relative to the smallest dotsize when jetted at equal dpd (droplets per dot).
2. The printing process according to claim 1 , wherein in step a) said radiation curable liquid layer is applied on a portion of said substrate by ink-jet printing.
3. The printing process according to claim 1 , wherein said radiation curable liquid layer is a clear liquid layer.
4. The printing process according to claim 1 , wherein said radiation curable liquid layer is a white liquid layer.
5. The printing process according to claim 1 , wherein in step a) said radiation curable liquid layer is provided on a portion of said substrate by ink-jet printing.
6. The printing process according to claim 1 , wherein said radiation curable liquid layer is a clear liquid layer.
7. The printing process according to claim 1 , wherein said radiation curable liquid layer is a white liquid layer.
8. The printing process according to claim 1 , wherein said radiation curable liquid layer and/or said first radiation curable ink-jet ink is suited for cationic polymerization.
9. The printing process according to claim 8 , wherein said first radiation curable ink-jet ink is a cationic radiation curable ink-jet ink without a cationic initiator.
10. The printing process according to claim 9 , wherein a said radiation curable liquid layer further includes a cationic initiator.
11. The printing process according to claim 1 , wherein a cationic initiator is present in said radiation curable liquid layer.