Ink build up then spits after 10k

Discussion in 'Heidelberg Printing Presses' started by Cal, Feb 26, 2018.

  1. Cal

    Cal Member

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    Hi guys,
    My first post here and would like some thoughts on a print problem, in that the ink builds up on either blanket or plate cylinder or there's a ink transfer issue that's not yet know.

    2009 Heidelberg SM 102 10 P.
    Sequence is Kcmy X Kcmy. The issue is clear on print unit 3. - Magenta.
    Perfected on 90GSM 635/880 gloss stock. Fount is substifix from Hostmann. ( recently changed, but hasn't helped) inkredible maxxima from.huber. Alcohol press. Non UV. Ink spitting only on first Magenta unit. A check of roller settings looked fine. Steel to damp forme is within stripe tolerance, as I thought dampening system was bouncing on plate cylinder causing the ink flicking. Within 8k impressions noticeably ink building up in the area just below the rear plate clamp. (plate is predampening fine, colour control is consistent through run and not varying. Oscillators to formes to plate all checked. Z roller 2mm. Vario working as it should, damp forme getting drive from matte chrome ok. Blankets and packing haven't changed at all. Air blowers switched on alittle to blow edge of rollers. Could it be a pressure difference from plate to blanket causing insufficient take off, resulting in squeezing ink towards tail edge? Water is at what I think it's minimum, as another possible thought was ink carrying to much water resulting in vehicle being separated and having no where to go but start flicking. Any thoughts or questions would be a great help hoping to figure this out or have I missed something really obvious if Ive left out anything please let me know and ill do my best to supply information.

    Any time spent helping would be hugely appreciated.

    I've supplied a picture of tail edge of removed plate after print run. Ideas?

    Regards, Cal.
     

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  2. Cal

    Cal Member

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    Colour management using scanner to iso. So densities are within tolerance so I can rule out that as far as carrying too much.
     
  3. Ricardo

    Ricardo Member

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    I had the same problem with my Heidelberg 102 zp. I replaced all the rollers and had the same problem. Try do put more strip from your water form to the plate. Or check your Z roller adjustment.
     
    Cal likes this.
  4. Cal

    Cal Member

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    Z roller is a good 2 to 3 mm. Matt chrome to damp is 8-10mm..

    What would increasing stripe on damp to plate achieve? I would of thought opposite, because initially I considered it being a dampener system overall clunk and bounce over clamps; with a stripe that was too heavy. Upon checks and resetting, ink still slings, and now safe to say that decreasing water further has made problem somewhat worse. Ideas?

    Thanks Ricardo.
     
  5. Ricardo

    Ricardo Member

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    How about isolator to water form?
     
  6. Cal

    Cal Member

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    Which dampener oscillates?
     
  7. Andrei83

    Andrei83 Member

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    Water rigidness, ph? conductivity. What dosage of alcohol?
     
  8. junker1984

    junker1984 Senior Member

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    Believe he's speaking of matte chrome, part of the dampening system, Cal. Is this across whole sheet??
     
  9. Andrei83

    Andrei83 Member

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    Check concentration of alcohol, the areometer separately. I think at you not enough alcohol, the dipping roller is soiled with color?
     

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  10. mantman

    mantman Senior Member

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    A few thoughts to check:
    -Condition of rollers and their hardness
    -Ambient temp of room at startup and after 10k imps
    -Temp of fount at each unit
     
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