yellow unit,,,questions?????

Discussion in 'DI Presses' started by DI.PRO.GUY, Nov 4, 2009.


    DI.PRO.GUY Member

    Jul 2009
    New York
    this is my problem,,after i stripe yellow unit to the plate,,,i start up my press and drop the form rollers down for the yellow unit and the "sliver allen screws" start to "bounce",,
    i know im doing something wrong,,,but what???

    also besides that,,,how do i get a tone issue off the bottom of a printed sheet 18.125 ,,just above the color bars
  2. 2ampress

    2ampress Senior Member

    Nov 2009
    As far as the bounce...that seems normal as the bounce time is in the dead area of the rotation when the rollers do not make contact with the plate material.

    Usually if you back off the pressure on the 3rd form roller, your tone will go away...sometimes it has to be completely away from making contact with the plate.
    Toning is usually more prevalent on uncoated stocks, but can also show up on coated as well. There are a few things to check to reduce toning...
    1. keep press room temperature below 75 degrees
    2. If the viscosity of the ink it too fluid, you can add heavy water fighting varnish to thicken it up. On a side note...Heavy water fighting varnish is the additive you can use to add to any standard offset oil based press ink to make it work on your DI. Usually about 15-20% of the overall ink volume should be the varnish to make it run nicely on the DI. If you add too much you will know because it will require you to open up your ink keys much more to get the right density, but your dot gain will be quite heavy.
    3 Check the cooling unit for the DI and make sure it is fully charged with water and it's temperature is set around 21 degrees.


    Last edited: Nov 14, 2009
  3. kev c

    kev c Member

    Aug 2009
    liverpool uk
    Your number 3 forme roller is set too hard to plate,reduce setting strip across plate or even back number 3 off plate and roller wont bounce or cause the banding on your sheet. Make sure technotrans is not too high in temp and the bar pressure and water levels are ok.