Tinting Problem.

Discussion in 'Ryobi Printing Presses' started by KFarm, Feb 10, 2021.

  1. KFarm

    KFarm New Member

    Joined:
    Jan 2021
    Messages:
    1
    Location:
    Pennsylvania
    Running a Ryobi 940 UV LED press. Using Toka ink. been having a tinting problem ever since the press was installed. I have tried several different kinds of fountain solutions. Rollers are set to specs.
    Ive tried different roller temperature settings. Water Temp settings and everything else you can think of. But still have the issue. On coated sheet the problem is manageable and most times after i get running the problem seems to go away. Uncoated sheet is worse. I know Calcium is a problem with paper and also I know that they use it as filler in the LED inks. Now, with all that said, I am able to run every type of job but the tinting is always on the gripper edge of the sheet. about 1/4 inch up from lead edge of the sheet. Im beginning to think this is just a inherent problem with LED UV printing but I wanted to know if anyone is having this problem. If so, what have you done to fix it.
    Thanks.
     
  2. turbotom1052

    turbotom1052 Senior Member

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    Oct 2008
    Messages:
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    Location:
    Vermont
    verify and resolve any possible calcium issues and then troubleshoot from there.
     
    CSF likes this.
  3. jonprintz

    jonprintz Member

    Joined:
    Oct 2010
    Messages:
    24
    Location:
    Dallas, TX
    This is a problem that has popped up in several LED press applications that I am aware of. If rollers & pressure settings are set to specifications then you need to take a good look at fountain solution. This is a good time to get the technical representative from your fountain solution supplier involved to ensure that you are working with the best solution for your application.

    Calcium almost always comes from the substrate. It is not present in most inks.

    This is not an inherent problem with LED/UV printing and will be solved with the right combination of chemistry, inks, rollers, plates, and blankets.

    It's been awhile now, I hope that your problems have been resolved.

    Jonathan
     

  4. northern-andy

    northern-andy Member

    Joined:
    Jun 2011
    Messages:
    38
    Location:
    new zealand
    Make sure form roller oscillators are turned off and that the form rollers are not moving in the journal, if they are pack them out with litho plate shims
     
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