UV ink fails to cure in the correct place on the press.
As UV inks and coatings are exposed to ultraviolet light:
- Direct exposure to sunlight or to general lighting sources;
- Smell from ink;
- Ink is reticulating on top of the first colour (often screen white);
- Cured ink has poor adhesion to the film substrate;
- Lamp problems:
- Eliminate direct exposure to sunlight. Use UV filter covers on light above the press;
- Ink not sufficiently cured. Turn up UV lamp power to a minimum of 100 W/cm and check the lamp and reflectors are clean. Reduce press speed to increase UV lamp dwell time;
- Over curing the white ink. Turn the lamp power down to a point where there is no surface tack but good secondary ink reception;
- Excessive curing of the ink causing shrinkage of the ink film. Turn the power of the lamps down to a minimum and also check the dyne level of the film.
- Lamp Solutions: