1 cm " scumming like" in the lead

Discussion in 'Heidelberg Printing Presses' started by mz000, Jan 25, 2020.

  1. mz000

    mz000 Member

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    after 1000 sheet keep getting about 1 cm " scumming like" in the lead, increasing damping removes it for a couple hundred sheet and appears again, SX52, any thoughts, image attached
     

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  2. junker1984

    junker1984 Senior Member

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    Back pressures off on your dampening rollers, lightly pry on journals to find any excess movement (up/down, forward/back). Could be a blown bearing, worn journal box or combination of both.
     
  3. mz000

    mz000 Member

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    Thanks for replaying,
    Its brand new sx52, could it be dampening roller setting?
     
  4. junker1984

    junker1984 Senior Member

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    Brand new as in from the factory? If so, roller setting would be the likely issue. Did you not have a Heidelberg sanctioned instructor come in for training purposes?
     
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  5. mz000

    mz000 Member

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    thanks for replaying, appreciated
    Yes it is, and yes we have Heidelberg sanctioned instructor.
     
  6. Jack liston

    Jack liston Member

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    Hello make sure ink forms are not to heavy to plate or to much ossilation on first or last form also check that soloution is right conductivity.and enough soloution is being pumped to pan ! Good luck
     
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  7. alibryan

    alibryan Senior Member

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    If all settings are correct, you might try segregating the dampening system and running that way for a little while, to see what happens with your toning issue. It’s just one way to quickly find out certain things that are sometimes associated with various ink brands and tacks, and etch brands and types. Sometimes certain brand combinations, combined with a pressroom’s overall environment, can create a less than ideal printing state.

    And even though many people think or believe that an Alcolor dampening system should always be run integrated, it is not necessarily always the best.
     
  8. mz000

    mz000 Member

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    Jack liston,
    Thanks for replaying
    The form roller has been double checked, we dont check conductivity, we do check ph and its on limit, 5.5
    alibryan, what do u mean by segregating the dampening system, please enlight me., All consumbles are Heidelberg recommended.
    Important note: its more visible “increases” with high speed above 11, and disappear under 7.
     
  9. MacD

    MacD Member

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    I can only see a very small portion of what you are printing on substrate-wise. It looks to be a form of uncoated card stock?

    You could easily be pushing the black density higher than it is intended to go. In turn causing the defect you currently are having. While you push it’s density well past it’s limits, water will never be enough to fight off all the ink you are laying down, which explains why it keeps returning.

    I have also experienced a transition of running polarized filters as opposed to unpolarized filters prior. If you have made this transition, your density points could be currently off from previous equipment and spectro scanners.
     
  10. alibryan

    alibryan Senior Member

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    I think your problem almost certainly stems from an ink/water imbalance. And even though this is a (if not the) most basic fundamental of offset printing, you’d be surprised at how many operators/individuals within the industry fail to understand what ink/water balance actually means, and the importance of it. It definitely matters, and in more ways than just one.
     
    Last edited: Jan 28, 2020
  11. mz000

    mz000 Member

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    Thanks MacD, for replaying, appreciated
    it's 120gsm coated, decrease inking cause ink fading and if the density is high shouldn't i find other indications?! on the blanket or water pan roller?
     
  12. mz000

    mz000 Member

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    Thanks alibryan for replaying, appreciated
    actually english isn't my native language so, many of the terms and expressions used could be difficult to align with my experience and knowledge, that doesn't mean also that i'm veteran operator or so, but i do know exactly what emulsification is, good one and the bad.
     
  13. MacD

    MacD Member

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    Definitely. There are a few indications of running the ink too heavy. I have run into issues where it has been pretty heavy and the only indications I would see would be in the work and the printing plates. I would never see the water pan roller pick up ink in the troubled areas, only on ends where it has no where else to go. So we cross reference our inpress control with a color management software to tell us where exactly colors need to be. Sometimes our inpress scanner sends colors through the roof for reasons unknown. Could be our ink builds, could be the scanner is crap. But I know when a coverage is just too heavy.

    You are saying you drop density and it fades out? Should only take a very few numbers on the reference value to get your balance proper and achieve better quality results. Not a drastic drop in density.

    To touch on Alibryan's comment and the potential language barrier. He could be referring to roller configuration settings. Connecting/disconnecting the water and ink rollers. I always run in 1:1 configuration which separates the ink and water rollers on an xl106. Which is an entirely different type of machine than you operate on, so I am unsure how yours works. I will also comment on his environment comment as well. Lots of temperature regulating going on. Could definitely need some adjustments based off your location and shop climate. He just gave you some quick and easy assessments to look at and to find the right combination that works best for your situation.
     
  14. mz000

    mz000 Member

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    that what confuses me, no indication but that line in work, decreasing the ink even a few numbers pales out the color associated, as referred i think i should investigate overall environment too.
    about your comment on Alibryan's.. you mean the Z/bridge roller or the intermediate roller, right ?? i hope i comprehended correctly this time :), i did disengage it several times but not for all the job or from the start, beyond this point do you and Alibryan's referring to over emulsification of the ink ?!

    Thanks MacD again for the help offered and expressed patient to overcome the language barrier, really appreciated.
     
    Last edited: Jan 30, 2020
  15. mz000

    mz000 Member

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    many thanks for the help.. appreciated, and sorry for any language barrier glitches:)
     
  16. Bill Halliday

    Bill Halliday Member

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    Make sure the form roller end play is locked off , Lighten up the stripes to the plate .
     
  17. turbotom1052

    turbotom1052 Senior Member

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    If all else fails you can try moving your oscillation. This would just be a bandaid fix but often you can move the offending toning into the gap.
     
  18. Travis Young

    Travis Young Member

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    That really looks like simply too much ink causing emulsification.
    I run quite a lot of solids on cheap bond paper so that's a familiar looking problem.
    Maybe you could try a black with a darker pigment. I know dense black isn't really meant for 4 colour process work but it may help to confirm that this is actually what's going on so you can find a long term solution.
    I have to say that it makes me smile that someone can buy a brand new Speedy and have (what looks like) the same problems I have with a 40 year old GTO.
     
  19. mantman

    mantman Senior Member

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    Some problems defy age :) What plates you use? Try just for one job to move black last -CMYK instead of KCMY-.
    See if it scums last unit it could be ink or simply change brand/tack
     
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  20. Travis Young

    Travis Young Member

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    That will also identify if the problem is with settings on the first unit or if it's related to ink/plates etc.
     
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