Plate problems with UV ink
- Thread starter Nmeg
- Start date
gordo
Well-known member
Can the tint be easily washed off the plate or is the scum difficult to wash off the plate?
gordon p
It's very difficult to wash off and it starts soon after switching over to UV.
gordo
Well-known member
If your problem looks something like this:
and it's difficult to wash from the plate, then, according to SunChemical's trouble shooting guide for this type of ink the problem is probably "scumming". The fountain solution is unable to keep the non-image area of the plate clean.
Their suggestions are:
1) Ink rollers are of the wrong durometer (too hard or soft) - Check durometer, setting, and condition of ink rollers.
2) Ink or dampener rollers are set too tight. - Check and reset rollers.
3) Blanket is overpacked or not tight. - Correct packing and re-torque blanket.
4) Prolonged use of oily wash-up solutions has occurred. - Change to fresh wash-up solution.
5) Plate is not properly sensitized. - Consult with prepress dept.
6) Fountain solution is out of balance. - Drain pans and tanks. Refill with fountain solution of correct pH and conductivity.
7) Ink film is too heavy. - Change to stronger ink and/or consult with your ink vendor.
8) Roller train temperature is too hot. - Maintain 80° to 85°F surface temperature on oscillators.
9) Fountain solution is too hot on press. - Maintain fountain solution at 60° to 65°F in press pans.
10) Blanket is glazed. - Remove glaze or change blanket.
best, gordon p
Cornishpastythighs
Well-known member
Do you do a good Conventional/UV ink roller conditioning when switching your press to UV inks. Are your rollers covered in Chameleon Rubber compounds meaning they will work with Conventional/ Hybrid or UV inks. Same with your blankets.
If your problem looks something like this:
and it's difficult to wash from the plate, then, according to SunChemical's trouble shooting guide for this type of ink the problem is probably "scumming". The fountain solution is unable to keep the non-image area of the plate clean.
Their suggestions are:
1) Ink rollers are of the wrong durometer (too hard or soft) - Check durometer, setting, and condition of ink rollers.
2) Ink or dampener rollers are set too tight. - Check and reset rollers.
3) Blanket is overpacked or not tight. - Correct packing and re-torque blanket.
4) Prolonged use of oily wash-up solutions has occurred. - Change to fresh wash-up solution.
5) Plate is not properly sensitized. - Consult with prepress dept.
6) Fountain solution is out of balance. - Drain pans and tanks. Refill with fountain solution of correct pH and conductivity.
7) Ink film is too heavy. - Change to stronger ink and/or consult with your ink vendor.
8) Roller train temperature is too hot. - Maintain 80° to 85°F surface temperature on oscillators.
9) Fountain solution is too hot on press. - Maintain fountain solution at 60° to 65°F in press pans.
10) Blanket is glazed. - Remove glaze or change blanket.
best, gordon p
The image doesn't look like that, the non image area looks more like a streaky look but it could be number 8 or 9, problem is we are in Spain and it's very hot in the building and we don't have a refrigeration system for our fount, I'll buy some bags of ice next time we run UV and see if it helps.
This is something we've been wasting our breath with to the boss but he wont buy new rollers.
Temperature definitely seems to be your problem. Generally UV inks will require slightly lower running temps versus oil based inks. The body structure of UV inks are comparatively softer, less gel integrity, and you will be more apt to have tinting, toning and scumming type problems. The idea of the ice pack in your fountain reservoir is a good one. For the record, I normally see reservoirs for UV at 50 F with water pans averaging 60 F. Good luck sir.
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