Hickeys on blacks only

Discussion in 'Web-Presses' started by r32dan, Jul 14, 2010.

  1. r32dan

    r32dan New Member

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    hi there, i am having issues with hickies on blacks only (last colour in the tower). obviously firsts thoughts would be that it must be the black ink if it is not happening on the other colours! The reps ink have assured us it it not an issue with there ink. So has the paper company, under a microscope the hickeys appear to majority ink. any suggestions. cheers......

    Ps..KBA Comet, 5 yrs old....
     
  2. Data

    Data Senior Member

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    I'm sure you'll have checked for a defective roller or debris?
     
  3. r32dan

    r32dan New Member

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    yeah checked those, no issues with either.....
     
  4. lildaddy50

    lildaddy50 Member

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    You're running your black down last? Never heard of it. Try switching you sequence.

    Rod (old school)
     
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  5. Data

    Data Senior Member

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    Dont take it the wrong way but nomally you can see hickies by eye.

    Do you get the same result when you print black alone?

    Is it the black isnt sitting on the previously printed inks?

    Dave
     
  6. graphix emporium

    graphix emporium Member

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    Hmmm, what it could it possibly be?, soft blankets?, stuffed fountain rollers bearings?, collapsed bearings on a scavenger roller/maybe set to hard?, not cleaning your fountain rollers enough, wrong fountain solution mixture?, trap floating, ink to tacky and is piling cause it's cold/viscous?, paper PH is to high?
    ........It's a wondrous world we live in with out adequate deductive direction :)
     
  7. Print Consultant

    Print Consultant Member

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    More than likely a roller in the ink train somewhere. Middle inker that no-one likes changing probably.
    Try using a heat gun on the rollers in the black unit, That should narrow it down.
     
  8. Peri Printer

    Peri Printer New Member

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    I would agree a roller breaking up first port of call might be worth checking the shore hardness of the inking rollers.
    If all rollers are good try a different ink and if you have spare unit use it as a duster before the blk unit.
     

  9. Travis Young

    Travis Young Member

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    Location:
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    How many black units?
    Does it happen on all black units?
    Or is the problem specific to one unit/roller train?
    Had a wrap recently on that unit?
    Maybe hand wash the unit and see how much crap ends up on the rag?
    If it's over every black unit the cause will likely be different to than if the problem is specific to an individual unit.
    I'm no web expert. I spend one night a week helping print newspapers on an old Goss Community Press but the fundamentals are still the same as sheetfed.