KBA marking problem

Discussion in 'KBA Printing Presses' started by Chris Thompson, Sep 6, 2019.

  1. Chris Thompson

    Chris Thompson New Member

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    Having problem with C1S stock being marked on coated side. This problem is random and does not repeat sheet to sheet. 2 pictures show the marking on the coated side and the uncoated side of the sheet above. 2 different papers are being used, problem only affects 1 of them. Paper affected is .012 C1S from Tembeck, paper not affected is Tango .012 C1S. Any ideas? KBA1.jpg KBA2.jpg
     
  2. Anthony M.

    Anthony M. New Member

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    Hi Chris,

    What is the configuration of the press?

    I have already encountered a similar problem on a KBA with several varnish groups, do you have a varnish group out of pressure as a result of your printing?
    The cause may be a light deposit of ink in it.

    Or a deposit of ink / varnish on one of the many leaf guides in the press, causing these traces.
    [From Google Translator]
     
  3. Chris Thompson

    Chris Thompson New Member

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    No varnish or other coating. Marking/offsetting only on gripper edge.
     
  4. Chris Thompson

    Chris Thompson New Member

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    And, happening on 1 manufacturers stock only.
     
  5. alibryan

    alibryan Senior Member

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    Setoff caused by sheet delivery.
     
  6. Chris Thompson

    Chris Thompson New Member

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    Why not affecting both stocks and why random? Appreciate your input..
     
  7. alibryan

    alibryan Senior Member

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    Different stocks deliver differently because they’re made differently...and setoff is almost always random. Hard to say without being there but probably the stock having issues has more of a down-curl to it, and if so, it might be causing the gripper edge side of the sheet to contact the sheet below it. There are other possibilities, as well.
     
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  8. turbotom1052

    turbotom1052 Senior Member

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    Is the grain direction on both stocks being run the same?
     
  9. Gregory Ross

    Gregory Ross Member

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    If the transfer drums are in , take them out. you don't need them anyway
     

  10. Gregory Ross

    Gregory Ross Member

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    you're right, short grain could be a problem
     
    Last edited by a moderator: Sep 16, 2020
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