The line up for printing involves five components: ink pan, fountain roll, anilox roll, plate cylinder and impression cylinder. Each one is needed to complete the flexography process.
The ink pan, laid out first, is placed on a smooth surface and is a large industrial type bowl filled with ink. Suspended partially in the pan is the fountain roll which transfers the ink in which it is dipped into, and places it onto the anilox roll as each one is rotating.
Once the ink is brought up to the anilox roll, the roll is then covered with a certain amount of ink by way of its small dimpled surface. Excess ink is scraped from the roll using a scraping or “doctor" blade. The dimpled surface of the anilox roll is what ensures that the right amount of ink needed for printing is able to transfer to the plate cylinder.
The plate cylinder is then rotated to allow for ample ink coverage on the raised areas that will be printing. As the cylinder rotates the impression cylinder is pulling the printing material through to be printed. The type of printing material used can vary depending on the need of what is being printed. For example, in newspaper printing a paper would be attached to the impression roll, but for a packing need there could be cello wrap being pulled through on the roll.
It is also important to note that water based inks have come a long way since first being used and there are some now that have a low smearing factor. This means that for this printing process many types of printing ink can be used.