What is the proper way to restore and re-ink old typewriter, calculator, dot matrix printer, and mainframe lineprinter ribbons?
Usually fabric ribbons or open-cell foam sponge rollers were used to hold ink for these machines. When the ink dried out, you'd take off the ribbon or roller, throw it away, and install a new one. But since most of this technology is obsolete, the supply chain for replacement ribbons/rollers shut down long ago.
But an old ribbon or roller probably could be recovered. There is probably still ink pigment on it, but the ink has become dry, so it won't transfer to the paper anymore.
Since most printer ribbons are exposed to the air all the time and are not capped/sealed between uses, the liquid must be very slow drying.. I assume the original ink was a mix of some kind of light oil plus pigment. Possibly a super-slow-drying "rubber" ink like is used on newsprint and offset-press systems.
I am mainly talking about solid black ink ribbons. I assume the special multi-color ribbons with bands of ink on a single ribbon (like the Cyan / Magenta / Yellow / Black for the Apple Imagewriter II printer) are a lost cause with little to no hope of making it work like new again. Or is there also a solution for restoring/re-inking those?