Flexo Printing

Flexography (often abbreviated to flexo) is a form of printing process which
utilizes a flexible relief plate.

It is basically an updated version of letterpress that can be used for printing
on almost any type of substrate including plastic, metallic films, cellophane, and paper.

That's why it's widely used for printing on the non-porous substrates required
for various types of food packaging (it is also well suited for printing large areas of solid color).