polyart print washout

[mrboneyard]

I am running a job on 140grm polyart on a lithrone 528. i set the job up with 140grm gloss and the quality of the print is perfect until the first sheet of polyart is delivered. The print is totally washed out with water and if i reduce the water the job is scumming. i have run this job several times before and have seen the print slightly washed out but never this bad. I would appreciate any comments on this matter?

 

[FSA]

mrboneyard
Do you use copper plating solution on the rollers? Have you checked your nips lately. And what etch are you using, with or without alcohol ?
FSA

 

[SteveSuffRIT]

I know this is an old post from 2011 but ......
Polyart from Arjobex is a synthetic plastic paper.
Maybe the washout is really a beading up or reticulation of the ink?
Check the surface energy with a dyne marker/pen or solution.
You want it to be greater than >40 dynes.
Corona treatment is often used to get better ink lay.
I wonder if both sides printed the same way?

 

[Erik Nikkanen]

I know this is an old post from 2011 but ......
Polyart from Arjobex is a synthetic plastic paper.
Maybe the washout is really a beading up or reticulation of the ink?
Check the surface energy with a dyne marker/pen or solution.
You want it to be greater than >40 dynes.
Corona treatment is often used to get better ink lay.
I wonder if both sides printed the same way?

Maybe of interest.

Tests were done on a test press in 2004, where the ink feed was modified so water would not affect the amount of ink fed into the roller train. UV ink was run and printing was done on uncoated, coated and plastic coated substrate. The test were to demonstrate that if the ink feed was modified in such a way, increasing the water would not affect solid print density.

All tests showed that even if the water setting was set to the max, the print density was not basically affected. The plate was soaking wet, way past normal operating conditions. For this specific test with the ink that was run, surprisingly dot gain and print sharpness was not affected much on coated and uncoated substrates. But printing on the plastic clearly showed the affect of water on the sharpness of the print. Edges of the print were disturbed by the excess water.

One of the conclusions of the test is that washout is only caused by a loss of ink feed into the press. Also printing on plastics or metal, where water does not get absorbed into the substrate, can be helped by a modification of the ink feed.

It would have been nice if other groups would have done similar tests to see if they would get the same results.