Dampening form roller

Discussion in 'Heidelberg Printing Presses' started by Raman karthi, Apr 27, 2022.

  1. Raman karthi

    Raman karthi Member

    Joined:
    Aug 2020
    Messages:
    56
    Location:
    nigeria
    Dear members

    I'm running CD 74 2003, this machine dampening unit doesn't have intermediate roller, while printing dampening from roller getting too much ink. And printing coming light on the paper.

    Don't know what reason is this, any ideas most welcome.
     
  2. Adil

    Adil Senior Member

    Joined:
    Nov 2021
    Messages:
    302
    Location:
    Casablanca
    The intermediate roller (Z) is an essential roller to have a good print quality, it is he who balances the amount of water and the ink transmitted to the plate.
    On start-up it imparts a layer of ink to the dampening roller before it takes on water and this helps to avoid unstable emulsion and you can produce with the minimum balance of water and ink.
    If you do not have this intermediate roller, the dampening roller takes the dampening solution first, which causes printing problems and in particular the unstable emulsion.
    Instagram : adilberg.tec
     
    Last edited: Apr 28, 2022
    asem alsafady and Raman karthi like this.
  3. turbotom1052

    turbotom1052 Senior Member

    Joined:
    Oct 2008
    Messages:
    969
    Location:
    Vermont
    I would suggest that since you have no intermediate roller that you fully ink up your water form, instead of allowing it to pick up ink zonally. You might also want to consider using your air curtains to manage your excess water that may be contributing to your unstable emulsion.
     
    asem alsafady and Raman karthi like this.
  4. alibryan

    alibryan Senior Member

    Joined:
    May 2014
    Messages:
    188
    Location:
    Somewhere
    I could go on and on about the advantages/disadvantages of integrated vs. segregated printing, but everyone has their own experience and opinions. What I will say is that there’s at least one major press manufacturer that recommends always running segregated (bridge roller off) and those presses print like there’s no tomorrow and are some of the best that money can buy.

    It’s also worth noting that old school Heidelbergs used to only come with segregated dampening systems (no z roller), and that’s the way it was for many years. However, with the advent of the ‘alcolor’ system, along came the z roller and it’s been that way ever since. Engaging it is still optional though, and I’ve run my share of jobs without it. Arguably, running with it engaged is ‘easier’ for achieving a quick ink/water balance, but in my opinion (if the press is correctly adjusted), you can produce better overall quality without it.
     
  5. Raman karthi

    Raman karthi Member

    Joined:
    Aug 2020
    Messages:
    56
    Location:
    nigeria
    Thanks for your answers dears, I will follow to setup your ideas.
     
  6. Raman karthi

    Raman karthi Member

    Joined:
    Aug 2020
    Messages:
    56
    Location:
    nigeria
    Ok sir, thanks, evening air also not working on All units. Already removed from the machine
     
  7. turbotom1052

    turbotom1052 Senior Member

    Joined:
    Oct 2008
    Messages:
    969
    Location:
    Vermont
    what is "evening air?"
     
  8. Raman karthi

    Raman karthi Member

    Joined:
    Aug 2020
    Messages:
    56
    Location:
    nigeria
    Sorry sir, it was a mistake in typing; I meant inking unit blowing air bar.
     
  9. Jack liston

    Jack liston Senior Member

    Joined:
    Sep 2019
    Messages:
    119
    Location:
    Connecticut
    Evening Air is an after dinner Fart!
     
    junker1984 likes this.

  10. alibryan

    alibryan Senior Member

    Joined:
    May 2014
    Messages:
    188
    Location:
    Somewhere
    The adjustable slide valves on the air bar are for evening out the air. Hence - ‘evening air’!
     
    junker1984 likes this.
Loading...