LED UV Chalking Problem on HB

Discussion in 'UV' started by AKJ, Mar 16, 2014.

  1. AKJ

    AKJ Member

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    Anyone having a problem with chalking with the new LED UV.
    I have a customer that made the transition about 10 months ago
    to run their Tyvek work. LED UV is installed on a HB SM102 after the perfecter and end of press. The sheets look great and feel set but in the finishing department there is buildup of what looks like chalk on everything to sheet touches. It is not causing any overall quality issue other than some extra maintainence to clean up.
    I am trying to determine if this is caused by the UV, Ink, or the substrate.
    Any Ideas?
     
  2. Ade

    Ade Member

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    Hi AKJ

    Just one question has the stock/ink changed for LED UV?
    Is the Spray unit still spraying is it still required to spray with LED UV?

    Ade
     
  3. AKJ

    AKJ Member

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    Yes the ink and fountain solution are matched to the LED
    System. Because the surface is set and dry NO powder is being used.
    They just showed me a sample of a job printed last July on Herculink that is dry to the touch and tape pull but still scuff when rubbed against each other. I'm running out of ideas
     
  4. Ade

    Ade Member

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    Hi AKJ

    Just looking into H UV/LE UV/LED UV at the moment so not got any experience with it, The only thing I can think of what are the rollers like when the press is washed up, if they are covered in calcium then it would suggest that the inks are the source, I assume they are using an RO system if not then the fount could also be a source to the problem, other wise maybe the LED UV is reacting to the stock what are the moisture levels before and after printing, is there any evidence of surface damage to the stock, maybe get the paper supplier involved you may not be able to run all stocks with this system with out getting some degradation?
    As far as rub resistance If you Look at the other LED UV Post no2 from Mancco he says there are some power issues with LED UV if that is so then it may not be fully curing the inks that may be causing the rub off or the ink may require reformulating?

    Hope it is of some help I expect you have covered every thing already.

    Ade
     
    Last edited: Mar 20, 2014

  5. AKJ

    AKJ Member

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    Location:
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    Ade
    Yes all this things you mentioned are in place. RO unit, new rollers ect.
    After bringing in another ink vendor and having the same results it seems the problems are a side effects of the substrates and the high ink film thickness my clients runs. The LED UV is definitely the way to go even with the higher upfront cost. The ROI is in the power savings and array longevity. AKJ
     
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