Desensitising damp system steel rollers

We run a Ryobi 524 HE and are based in the UK.
We are having a problem keeping the steel between the metering roller and the water form roller clean.
Tried cleaning with acid and then gum Arabic but no joy.
Replaced metering and water form rollers but problem persists.
It is not the whole steel roller that is inking up, only ink banding around certain areas but not allways the same spot.

Any tips on desensitising the steel appreciated.

 

we use a chrome roller cleaner and desensitizer everyday after we wash up. It works well.

 

you can start by either doing a deep cleaning of ink rollers along with a calcium rinse or pull the ink rollers out and scrub all of them by hand to remove all traces of calcium. Once you know that your inker is free of calcium I would suggest doing a thorough etching of your steel water rollers. Try mixing a batch of cleaner as follows... A few ounces of AGE, along with a squirt of plate cleaner, along with a sprinkle of cream of tartar. Mix this concoction up a bit and work it into the steel water rollers in a brisk circular pattern, with a cotton wipe, rubbing with decent pressure until the steel rollers are fully cleaned. Repeat this procedure every Friday allowing the mix to dry on the steel rollers over the weekend. When your ready to start up the press on Monday morning just wipe down the system with CLEAN tap water.

 

This works for rilsan rollers too or only steel? -what is AGE?-

 

not for rislan rollers, just steel and metallic coated damper rollers. AGE is usually used as a long term plate storage preservative. Its a brown liquid comprised of Asphaltum, Gum, and Etch.

 

We just call it...gum so you mix arabic gum+plate cleaner+cream tartar. How can you tell rollers need this type of cleaning? They pick up ink frequently?

 

If the stuff you're using is dark brown and needs to be shaken before use, then you've got the right stuff. If it is in fact AGE then gum is actually just one of the 3 components. When you mix up a batch of the stuff I mention, you create something that serves 3 purposes. The cream of tarter is a very mild abrasive that aids in thoroughly cleaning the steel roller. The etch component of the AGE lightly etches the surface of the steel, and cuts through any residual oily film that has built up on the surface. The gum in the AGE helps to make the surface of the steel roller hydrophilic. Hydrophilic is the roller surfaces ability to be receptive to water. As long as the steel rollers surface is receptive to water, and capable of maintaining a film of water, then the ink will not be able to adhere. This is the very premise behind lithography!!! By making this a regular part of your press maintenance routine you will be able to keep ahead of any residual buildup on the presses water system.