2007 CD102 double image

Discussion in 'Heidelberg Printing Presses' started by Kris, Apr 23, 2020.

  1. Kris

    Kris Member

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    Hello everyone,
    I am having a double image issue anytime I run my first unit. I have already checked the grippers and cams and don't see any issues. It comes and goes sheet by sheet. Sometimes one sheet will be perfect and the very next will bee blurry. I know paper stretch is a factor in this, but wanted to know if anyone knows of an adjustment on presentation can help keep the sheet from blurring. I attached a photo for reference of what I am dealing with. Thank you for help provided!
     

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  2. junker1984

    junker1984 Senior Member

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    If the complete image looks like this, particularly on start up or after even a brief stop and go to wash blankets, you've got a blown thrust assembly on impression or triple drum.
     
  3. Kris

    Kris Member

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    Its continuous through the run. D.S. corner on tail edge of sheet. It will go back and forth from clean to blurred on just the one color while running.
     
  4. junker1984

    junker1984 Senior Member

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    Have you tried "working" the grippers from both sides of impression through all three transfers? Given only when running PU1, it could be one bad (sticky) gripper and by the time the sheet gets to unit 2, it may be ironed out. What stock thickness? Does changing stock change problem? Is this happening when guiding either side?
     
  5. Kris

    Kris Member

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    We only run 60 C1S and only ever guide on the O.S. I will have to go through and see if any are sticking. We did that a while back and didn't notice anything, but maybe we missed one.
     
  6. junker1984

    junker1984 Senior Member

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    In that case, I'd also suggest that since you only guide on one side, lift the guide and free run the sheets. Issue you're having may stem from a worn lifting roller a a worn guide lever. Also, be sure you're not guiding into a swing gripper pad, meaning shift pile a bit either way to stop short of/guide over the top of pad.
     
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  7. asem alsafady

    asem alsafady Senior Member

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    Hello everyone,
    For me all the points that Junker mentioned are very important.
    But I need some more information.
    Try to print at your first unit (impression is off at other units), does the problem exist?
     
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  8. Kris

    Kris Member

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    Thanks for the ideas guys.
    Asem - This is going to be the next thing that I try doing. I was thinking that I would turn on one unit at a time until I see the problem to try and isolate where it is happening.
    We also have three different air controls at each unit. One is a cardboard blast tube, next is the paper blast tube, and last the Printing Nip Blower Bar. Could too much air from these be causing a problem with sheet position between grippers? I never received any training for these settings and seeing how differently they are set between each unit is leading me to believe this may be part of the problem. Please correct me if I am wrong.
     

  9. FourFingerRing

    FourFingerRing Member

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    Possible sheet wrinkling also by the looks of the picture. Curl of stock prior/simultaneously to entering infeed. I cannot see the entire sheet but if the double image carries into the other image on the sheet from tail edge towards the gripper but doesnt continue all the way to the gripper this could also be the issue. The inconstancy of the defect could be paper related also. Some stock curl and or rh values add the the come and go effect. Like others have said check side guide for defects and/or grippers and air. Most likely air from the first unit impression doesnt take effect until after impression, following the transfer drum into the 2nd print unit. On most presses.
     
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