White Dots during Printing specially on Solid Surfaces of the Print

Discussion in '4-Color Offset Presses +' started by cooladi006, Oct 20, 2016.

  1. cooladi006

    cooladi006 Member

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    Location:
    Chennai, India
    I face frequent rejections of Pharma Cartons because of small dots which pop out despite appropriate care being taken to observe while printing.

    Ex. 1) Solid Cyan Surface has a white dot
    Ex. 2) Solid Red surface has a yellow dot

    I am ready to upgrade all my quality of materials which I use which can help me carry a worry free printing job. Please help me with the possible reasons because of which such dots could occur and how can it be avoided.

    Thanks
     

    Attached Files:

  2. rolandman

    rolandman Senior Member

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    how often do you wash up, do you use alot of spray powder, is the print room generally clean? this is all down to how clean the press is.
     
  3. seanryder

    seanryder Member

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    Looks like plain ole hickeys. Dried ink migrating around the ink or water system.
     
  4. aqazi81

    aqazi81 Senior Member

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    These are hickeys coming from your rollers or your substrate.
    From rollers, it can be dried ink or the rollers are worn out, it can be the rubber coming out and sticking to your plates. Check and clean rollers, replace if needed.
    Clean your water circulation tanks and water pans, use a system cleaner to clean out the hoses.
    If your substrate is sub-standard, change it. If you have 5 color press and you are running four colors, run them in last four units and put the 1st unit on impression to pick some hickeys there.
    In some presses there are retrofits offered that can clean the substrate surface before the 1st print unit.
    You can also try low tack inks or reduce the tack of your existing inks with CP Compound or printing oil.

    I hope this helps.
     
  5. MacD

    MacD Member

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    Hickies can also be caused by the type of ink you use. If it is running light it will reduce its chances to fight these hickies off the plate. Aqazi is also spot on with his assessment. Hickies are a part of the printing game. Constantly fighting them I would get the ink and water reps in to help.
     

  6. MacD

    MacD Member

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    Also looks like you are printing on ccnb(clay coated news board). The substrate on that board is horrible and always breaks up. By the small image, that's what the board looks like to me. Always fighting quality with that board
     
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