printmaster color contamination

printing unit two contaminating print unit one on the operators side stripes all look good any ideas

Hi,

Could be not enough damp solution on 1 side, thus allowing the plate to scum slightly and then transfer the ink via the blanket to the other unit.

Which unit do you generally run the lighter colours on.

Regards.

Check the Water/Fountain Solution PH always.

this is for a quickmaster 46-2? check if your machine is levelled properly. if it tilts towards one side, the fountain solution may not be reaching the operator's side, and could cause the scumming, thus the ink contamination.

does unit 1 print ok if used for single color?

I have exactly the same problem, except it is the non-operator side of the machine. The problem only starts after about 2000 impressions. The rollers are new, the machine is level, and when the problem occurs I can see fount in the tray so I assume my bottle hasn't got an air lock problem.

As soon as the plate scums at the side and creeps in to the sheet I have stopped the feed and looked at the plate from under the feed area and the plate appears to run clean again. I'm confused by this as unless I wash up and start from scratch the problem just keeps coming back. I did think I had found the culprit as I noticed a build up of ink on the tail end of the plate on the non operator side of the machine where the plate appears to not have clamped flush to the cylinder, I corrected this but the problem still came back.

I'm really puzzled, any ideas as to why this is happening would be much appreciated.

Sorry I forgot to mention PU1 prints perfectly.

Double check your roller settings on the damping system, if you have ALL new rollers in, there is a good chance one of the ink strips will be incorrect.

Regards.

I have to put my hands up to this one, after checking all my roller settings again, there was no stripe between second form to oscillator, how I did this I don't know.