Massive lint build-up on plate and ink unit

[Niclas]

Hi
We have a problem with our web offset press.
Its a Solna Bookline running only black color and we use it to produce paperback books. We have chilling rollers set to 18C*
After a couple of thousands of copies we can start to see a lot of lint build up on the plate and in the ink unit. All the black areas starts to have missing dots (I think the thick layer of ink/lint mixture makes it hard for the plate inkers to transfer ink to the "the bottom" of the plate, when the ink has been transferred to the blanket cylinder) and the ink unit consists of some mix between ink and paper lint. If we drag our finger across the plate we can feel the thick layer of ink/lint mixture. (see attached picture, red dots is one place were we see the white dots on the paper where it should be all black, note that the entire picture/leg should be black)
We have tried multiple inks and fountain solutions. Its worse on the left sides (our tower is with 4 inking units, 2 left, 2 right).
We have also tried different blankets, but with no success.
We can not see anything wrong with the roller settings.

What can we try to minimize these problems we are having?
What impression is recommended to have on a bulky uncoated paper?

Best regards
Niclas

 

[Dan Roll]

The firt thing I would try would be to reduce the tack of the ink. Try linseed or Chinawood oil.

 

[Green Printer]

We have used a fountain solution HSCHR from BestChem Supply that has eliminated all of the lint issues. I talked to some other users who have said that this is a game changer in web fountain solution. One of the users reported going from cleaning blankets every 7,00 to 8,000 impressions to over 80,000.

You can can contact them at [email protected]

 

[Ncharge06]

If you have an open unit before the the first printing unit you can use a water plate (exposed plate with just the water rollers, not inkers) with impression on the unit. I do this all the time if I have the open unit, you'll be amazed what it "pulls" off before printing. Works great to pull powder or lint off the sheet.