Chrome metering roller on pm74 keeps picking up ink issue

Cornishpastythighs

Well-known member
Is it picking ink up all over or in only one area, are all units doing it or just one? have you had a FS or ink change to a different supplier, when did it start
 

jshawy

Member
My ryobi 3304 does the same thing all I do is clean the roller with heavy duty plate cleaner then wipe over with a damp cloth
After cleaning off the plate cleaner you should apply gum and buff dry to properly desensitize the chrome. Don’t use the plate processing gum it’s too acidic. Get a neutral PH gum.
 

keith1

Well-known member
My 2 cents to the above. When shutting down for the day I always used chrome cleaner and finished with gum arabic. It could take several days of treatment to 'season' your roller.
 

Alois Senefelder

Well-known member
Gentlemen and Fellow Lithographers,

Steve, correct- the reason for using 8 Baume is less chance of "Gum Blinding" - next

Enlightenment PDFs
 

SheetSqueezer

Well-known member
For what it’s worth; the chrome rollers in a dampening system aren’t actually the metering rollers, they’re either the pan rollers, and/or oscillating distributors. Metering rollers are almost always made of rubber, and on a Heidelberg press with alcolor dampening, it’s the roller that sits in the water fountain pan.

As for chrome rollers inking up -

Many companies make chrome roller cleaner (some more effective than others) and there are also different times and methods to use those cleaners;

- before start-up at the beginning of the shift
- after clean-up at the end of the shift
- anytime throughout the shift, whenever needed

Sometimes followed with either/or, but not both;
- gum arabic, to protect roller surface
- etch, to help keep roller surface wet

*With a little luck and if your FS is compatible with your ink (they work together correctly), and/or your operator‘s routine is a good one, you may hardly ever need chrome roller cleaner - and maybe not at all. I’ve actually seen it where one operator was using chrome roller cleaner, gum arabic, etch, etc., on a regular daily basis, and then with a new operator the chrome roller cleaning routine became unnecessary. Same press, same ink, same FS - but apparently a completely different operating routine.
 

Alois Senefelder

Well-known member
Gentlemen,

At last the - PDFs in 5 parts due to being over Max size, when I scanned.
 

Attachments

  • Desensitizaion - Gum Arabic125_1-1.pdf
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Last edited:

Alois Senefelder

Well-known member
Gentlemen and fellow Lithography

Explainer - There is competition for Metal Surfaces in Lithography between Ink(Fatty Acids) and Desensitization (Fluids) Gum Arabic/ FS Concentrates etc. Fatty Acids (Ink) usually win because they have stronger Molecular bonds than weaker Desensitization Bonds.

Regards, Alois
 

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