uv coating question

[viclpp]

Hey everyone I am new to this site. Can you do uv coat with only uv lamps and a ir dryer in the extended delivery unit without using inter deck uv lamp. We are still trying to use conventional ink. Also, was wondering if anyone know if PRI cold uv curing system is any good.


Thanks,
Victor

 

[arfamoe]

you should always cure Hybrid uv inks prior to uv coating. this should be done with an 'end of print' uv lamp after the last print deck then apply uv coating then hit it with another uv lamp after coating. It sounds like you only have a uv lamp after your coater? You cannot sucessfully uv coat over straight conventional ink and must use a primer coat between the conventional ink and the uv coating.

 

[dimitri]

I would expect to have issues with the UV coating over conventional ink, even after exposure to the uv lamps at the delivery. The coating, cured or not, could 'dive' in, rewet, or just not look smooth enough since you'll have all the chemicals in the wet ink film that would try to break through the UV coating as they are evaporating. It can be messy coming to think about it.
Hybrid inks is a better aproach. But still, depending on the total area coverage you might need to use one additional interdeck light after the black, and one after the yellow. If the light coverage is light, one light at the end of the process should suffice.

 

[viclpp]

thanks guys, our guy coming to install the new press said it can be done but i was sort of iffy about it. He said as long as you have a strong ir dryer to help dry the ink.

Thanks

 

[arfamoe]

So let me get this straight, you have bought a new press and the guy says that you will be 100% successful in printing conventional ink, drying it with IR then putting UV coating over the top and hitting the whole thing with a UV lamp and the end. Has this guy ever heard of Adhesion failure having conventional inks in contact with UV coating, not to mention conventional ink maybe never drying under UV coating. Your UV gloss level will appear good at first depending on the ink coverage but the next day will be a disaster. For these very reasons presses were sold with double coaters to allow a primer coat to be applied between the conventional ink and the UV coating.

 

[viclpp]

thanks for the advice. i probably just go the safe way and use hybrid ink.