coating on blanket problem

[henrym]

Hi all,
we are having an unusual problem with piling on our second down blanket, we are a cold set printer and run cmyk. The red blankets get a slick coating on them and can be hand scrubbed off but will not come off with blanket washers. we have not changed anything in our ink or dampening, the coating does not show up anywhere else and here's the kicker, we run two presses side by side, both run the same paper and ink. Also we are using the same blankets on both presses. One press has it, the other does not. Any thoughts??

 

[jonprintz]

Henry,
My first thought is pressure. Are all of the blankets packed the same? Check the bearer pressures next.

 

[henrym]

jonprintz,
This is a bearer less press and uses metal backed blankets. we've been thinking about impression pressure but it prints very well and registers very well also. I've wondered if something has gotten onto the ink but we use 5000lb toat's and are we are quite a bit into this lot of ink with no problems on the other press. I think we will try to lightly scrape a sample and have it analyzed.

 

[BreynnMike]

Same watertrain? What shop you at?

 

[HPC]

If your just trying to get around the problem for now, Varn has a non pile additive for your fount solution. You do need to figure it out for the long term, but this might help get rid of it on a short term.

 

[graphix emporium]

maybe some wear or damage in your drive train some where, if the surface speed is over or under a tad it might be creating some drag at impression and stripping off some minute amounts of the face stock and building up through the run. if all the consumables being used are the same on all other units and presses without problem then I would tend to think it is mechanical and worth a look into, maybe a worn keyway or a loose gear locking point somewhere in the drive train or maybe just worn gear teeth somewhere even. could even be a crap uni joint on the drive shaft if its shaft driven. maybe worth inspecting the gearbox if any, also just a clapped out bearing in the drive train somewhere could also be the culprit. just a thought