In simplest form, drying of an ink film occurs with conventional inks when the ink vehicle (solvent or water) evaporates or is absorbed, leaving being the solids (pigments, resins, waxes, etc.) to form a film on the substrate surface. Radiation cured inks are cured, not dried. The components of the ink or coating remain on the surface of the substrate, for electron beam (EB) inks, a concentrated beam of highly energized electrons. The difference lies in the chemistry of the materials in the inks and coatings and in the pressroom equipment needed to energize the curing process.
EB inks consist of low-molecular weight polymers that react with a stream of electrons from a vacuum tube. These inks contain no solvents and do not cure until exposed to an electron beam. Therefore, EB inks can remain in ink fountains for long periods of time, reducing clean-up needs. The electrons drive the reaction, forming polymers and setting the ink.
Electron beam dryers use polymerization by electron bombardment to dry liquid and powder coatings. These dryers have been coming down in cost and have low to moderate operating costs. Sometimes they are used for higher gloss coatings.