drying issue

Discussion in 'DI Presses' started by V-P, Apr 6, 2012.

  1. V-P

    V-P Member

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    First of all - I am a newbie in offset industry. Said that...

    I am facing a "copying" problem, if I can call it like that. Probably there is a technical name for it but I can't remind it now.
    Apparently the sheets are not dry enough and I get some ink from the underlaying sheet to the top one. I have lowered the speed to 3500, make small stacks, be generous on the powder but still I get some "copying". And I have a dryer unit on my Pro machine.


    What do you guys do to prevent that ?
     
  2. Marc Bremer

    Marc Bremer Senior Member

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    Is it coated or uncoated you have prolems with. Check your powder device is working properly (does it spray al all). Speed is not an issue, I alway run on 8000 SPH. At wich density's you print solids.
     
  3. V-P

    V-P Member

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    Hi Marc !

    It is coated (both glossy & mate). I use the standard density CM=1.4 Y=1 Bk=1.8

    I will make some tests on the powder unit to check it.

    Thnx for helping...
     
  4. Marc Bremer

    Marc Bremer Senior Member

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    I asume it's only on black build with CMY and K. Check if the total amount of ink doesn't get higher than 320%. What brand of ink you are using.
     

  5. V-P

    V-P Member

    Joined:
    Jul 2011
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    Location:
    Eastern Europe
    Hi Marc,

    Found the problem:
    The powder spray unit was not working at all. I did activate it and only air was spraying but no powder regardless of the max position.
    So I disassembled the powder unit and one piston (solenoid) which opens/closes the powder was blocked. So I open it clean it and now it snows in powder.

    Thnx for helping...
     
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