Flexographic printing, often referred to as flexo printing,
is a process that is used for printing on to basically any material; it is a
modern version of a letterpress.
This process which is used to print packaging materials uses
printing plates that are made from rubber or plastic, this material means that
the process is flexible
Although it used to result in a relatively low quality
print, recent advancements have meant that flexographic
printing is now the most commonly used printing process in narrow web
printing thanks to its flexibility, its high quality and its reliability.
The inks used in flexo printing are either water-based or
solvent-based, but are either way very thin, this means that they dry quickly
which makes this printing process ideal when several colours are used.
These printing machines essentially work by the substrate
being fed through a series of rollers, the desired image is printed onto the
material through the use of a printing plate, almost like a rubber stamp; with
each colour having its own station.
At each inking station there are four rollers; an impression
cylinder, a plate cylinder, an anilox cylinder and a fountain cylinder. The
bottom cylinder (the fountain cylinder) is partly in an ink tray so that it
draws ink from the tray as it rotates, this ink is then passed onto the anilox
cylinder which contains lots of engraved cells which allow the ink to be
received in measured quantities. This cylinder also uses a doctor blade to
remove excess ink, ensuring an even coating of ink. The ink is then deposited
from the anilox cylinder onto the flexible printing plate where it is then
ready to be applied to the substrate.
Flexographic printing allows for high speed printing in
large volumes and so is very economical, so it’s no surprise that it is a very
popular form of printing.
