UV white color problem

Discussion in 'UV' started by india286@hotmail.com, Feb 24, 2012.

  1. india286@hotmail.com

    india286@hotmail.com Member

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    i been printing Metalised mono cartons and have 2 color press.
    We started with white color and everthing is ok as soon as we reached the final printing i mean C+M 2nd pass and then Y+B 3 rd pass the white color printed 1st becomes dirty and yellowish what is the solution
     
  2. jaed

    jaed Member

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    do you have any close up pictures of the problem?
     
  3. saso777

    saso777 Senior Member

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    It can be a lot of things,check and clean rollers and if you can send picture.
     
  4. india286@hotmail.com

    india286@hotmail.com Member

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    it became dirty and yellowish only after when it gone 3-4 pass under UV curing system
    whether i print other colors or not doesnt matter only if i pass it 3 times under UV curing system it become dirty and turned yellowish
     
  5. Komory

    Komory Member

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    probably painted in the third run, goes to white .Sorry for inglish.What kind of ink you use?
     
  6. india286@hotmail.com

    india286@hotmail.com Member

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  7. Data

    Data Senior Member

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    If there is no signs of the white stripping from the substrate it sounds more like you wasnt using enough damp thus its tinting from the latter passes
     
  8. india286@hotmail.com

    india286@hotmail.com Member

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    enough damp??? means i use lesser ink while printing and should increase the supply of the ink to the sheet.???
    and no stripping is there we base coat the sheet 1st and then printing with uv inks
     
  9. eng reda

    eng reda Member

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    white color curing need special lamps
    are you have this lamps or not?
     
  10. india286@hotmail.com

    india286@hotmail.com Member

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    what kinda special lamps???
    its got cured with ordinary UV curing lamps
    if anything special then let me know
     
  11. Data

    Data Senior Member

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    I mean you might need more damp on the later colours. Dirty and yellowing white suggests your colours are scumming
     
  12. Andy-zhang

    Andy-zhang Member

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  13. Drew812

    Drew812 Member

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    Do a test put the white through the press 3 times before you put the other colors on to see if it's getting dirty, to see if the other colors are really the problem and not just getting toasted from 3 passes under the lights.
     
  14. Drew812

    Drew812 Member

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    We use a Toyo plastics white that works great on paper and plastic, and i put the same (make ready) through the press about 7 time and still looks white.
     

  15. india286@hotmail.com

    india286@hotmail.com Member

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    you mean to say there is no need of UV drying it works great on paper and plastic without requiring UV drying??
    sukesh
     
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