Page 6 - "How to print on flexo?" By Petra Bteich

At first flexography was called aniline printing and the
name persisted until 1951. Aniline printing, designed to

run with a central impression cylinder and surrounding
printing units, dates back from the 1890s. The name
“aniline printing” originated from the aniline dyes used
in the inks. The aniline dye was made of a coal tar

derivative and was later banned from food packaging
because of their toxicity (Herzau-Gerhardt 1999).
The first patented aniline printing machine (1908)
printed bags in-line with a bag-making machine

(Cushdin 1999a). The ink-metering was achieved using
two rolls, one for picking up the ink from the ink
reservoir and another for doctoring the ink film and
transferring it to a wooden or metal plate.