Black Plate Breaking Down Quickly Running Uncoated Stock

Discussion in 'DI Presses' started by impressed, May 13, 2015.

  1. impressed

    impressed Member

    Joined:
    Jul 2011
    Messages:
    47
    Location:
    ONTARIO CANADA
    On my Heidelberg QMDI, after around 5000 sheets of uncoated stock (20# Bond in this case) my black plate is printing lots of wee little dots all over the page. This is normal for me. Is this just paper dust wearing down the plate? Is this normal? Is there anything I can do about it?

    Gloss runs way better on my press, so this issue is unique to the uncoated stocks.

    Thanks
     
  2. Paul Cavanaugh

    Paul Cavanaugh Senior Member

    Joined:
    Dec 2009
    Messages:
    628
    Location:
    Kennesaw, GA
    Check your packing. The blankets should be packed to "0" bearer height +.02" max. Any more and the plates will wear prematurely.

    If the paper is not high quality you could get unusual amounts of paper dust sticking to the blanket causing the plates to wear. If the paper was cut with a dull blade could cause this also.

    If it is on your second pass, there may be to much powder on the sheet, the excess sticks to the blanket and wears the plate.

    Lastly, applying to much printing pressure may cause the sheet to break down, hence more paper dust. This typically happens after the sheet has been run through a couple of units and you start to see it on the 3rd and 4th unit.
     
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