Problem US11 Ink Adhesion Issue at Low Coverage on XPJ-461UF

[Chavo]

Hello everyone! I have MUTOH XPJ 461UF with US11 inks. I noticed that some of the prints are erased. I did tests with all colors with percentages of 10 - 100%. It turned out that up to 30% are erased very easily. From 40 they stick well and 100% is great. I did tests on different materials (PVC, laminated paper, even on coated paper up to 30% of the print is erased. Does anyone have an idea how to deal with this? Thank you!

 

[Chavo]

Has no one encountered this problem, or has it already been discussed and I look stupid?

 

[Ronny Axelsson]

I run a Mutoh VJ-626UF and US11 inks but cannot say I've noticed that lower percentages should be easier to erase.
Have to admit that I haven't tested for this specific issue though.
Sorry.

 

[Chavo]

So, this is the official ansver of MUTOH:
The adhesion when printing low density US11 ink, indeed is not good.
Usually, when priting more than 30% density, the curing should be sufficient.
If not, please make sure the lamps are on 100%, and the glass on the lamps are clean.
For your question on how to print low density;
- The only advise we can give is to add some varnish (15-20%) into the print.
- When mixing varnish with the colors, the 'density' will be higher which leads to better curing.
- Do not use varnish as a sub-layer, as this does nothing to help with the curing
Creating a custom profile might help as well.
We advise using the large drop family: Fixed M dots for colors, L dots for white/varnish

So if anyone encounters this problem - this is the solution. It's no wonder that the MUTOH website says "excellent adhesion" for US11 inks

 

[Ronny Axelsson]

Thanks for sharing, Chavo.
Wonder why lower ink coverage is harder to cure and get to stick than higher, one would thought it should be the other way around.

Honestly, the Mutoh UV printer has been one of my biggest letdowns over the years.
While it's capable of so much, it's also held back by so many limitations.