Troubleshooting Guide - Pressroom UV
On Press Issue: Chalking
Potential Causes
Ink is over-emulsified
Solution: Clean up the press, put fresh ink in the fountain and restart with lower water settings.
Substrate absorbs too quickly, causing a lack of binding
Solution: Consider using a size coat or a different stock.
The ink surface curing too much or not curing properly
Solution: For UV inks add through-cure photoinitiator 1% at a time up to a maximum of 3%.
The ink film thickness is too high. Not allowing the UV energy to properly penetrate the film and thoroughly cure the ink. This is especially evident in blacks and colors.
Solution: Lower the ink settings and/or weaken the ink.
UV lamps may not be providing adequate energy because of old bulbs, dirty reflectors and/or focal plane has become off standard
Solution: Check the lamp age and make sure that the reflectors are clean and check the focal plane. Check the lamp output.
Ink formulation is not allowing for enough crosslink density
Solution: For UV inks add photoinitiator 1% at a time up to a maximum of 3%.
