sm74

Hi guys
I am running a sm 74 5col and i am having problems with ink building up on the back edge of the blanket,imp cyl and transfer cyliders of the offending units.
I have checked fount,roller settings,changed ink,reset dampers.
I can move this build up to any place on the sheet by altering ink timing travel from grip edge to back edge on the side of the unit (eg. white 1 to white 5).I then get a tinted band across the sheet.
The problem occurs in both cnnected and disconnected modes.
This all seems to me that it emulsification problem,all roller settings are good to manual spec.
Does anyone think it could be connected to the water softening unit?
As i am beginning to run out of ideas
Thomas

 

This might sound silly but are your ghost busters on (ociliators set for max oscilation) i know when i engage them on my sm-74 i get alot of build up on back edges of cylinders.
Cheers Gazman

 

Most likely not the oscillators. If you see imulsification on the rollers, it could be led to an imbalance of ink and water. If you run alcohol freen and the dampening form and pan rollers are in good condition, your pan roller speed % should be any where between 30% to 45% on process colors. This of course also depends on if you have ink temp control for the ink oscillators. Good fountain solution is also key.

Harry W.

 

Thanks for your replys guys,
Checked oscillators,they are ok.Fount has been flushed and reset.Although conductivity was quite high,
ph was good.I am running damping between 30% and 40% on process colours.Rollers should be free from
contamination as they have been cleaned thouroughly.

 

Hi Thomas

I run a SM 102 Perfector and we get the same problem when the ink forms are set to oscillate. Check that your blanket packing is not too long at the tail edge of the cylinder.

 

Whats the best fountain solution and what would be good pH and conductivity readings? Im running a SM-74 and my waters are running anywhere between 60 and 85%. I'm also using soy-based inks and Emerald Jr. with ARF-S fountain solution (would like to switch to Saphira fountain solution).