Printing is magic for many people. Nowadays’s while many people use their home desktop printer it became a little bit more understandable. But in the past many simply didn’t understand how it worked.

The most simple printing process to understand is book printing. Just take some wooden pieces, scarf the wood so the letter is higher as the basement. Roll a roller with ink over the letter, press the letter on paper and you’re done. Just the same way as a stamp.

Then a new technique came, offset printing. For most people it was magic. Ink doesn’t like water. So, they used stones in the past, etched an image on the stone which was ink suitable. Make the stone a little wet and the water only remains on the non printing parts of the stone. Roll the inkroller again over the stone and the ink will only be there where the image is etched. Later they replaced the stone for aluminum plates which are very thin.

But offset printing has a disadvantage. You can actually only print paper and prepared plastic materials such as PP and PS with offset. If you print on unprepared PP and PS you can print on it but the ink will not get dry and is very easy to remove. Preparing plastic material such as PP and PS is expensive. So therefore the flexible printing industry is using two printing techniques.

One is similar to stamp printing. But here the stamp is not wood or foam like the stamps used to mark letter. The stamp are made of rubber and are very flexible. The printing machine has a cylinder able to have the rubber stamp glued on. The printing process itself is more and less the same as offset printing. We call this printing technique Flexoprint”
The second technique is rotogravure printing. Flexoprint has the disadvantage the rubber stamp has a limited lifetime. Mostly these stamps last no longer as 50.000 to 100.000 prints. It means when the production has an amount more as 50.000, which is many times the case in bulky food packaging, you need an extra stamp. This can cause difference in color and the costs are also raising.
For higher amounts the flexible printing industry uses the same technique also used for magazines in large amounts, rotogravure.
In this technique the image is sunken in a thick metal cylinder. The ink is added by a roll and the rest of the image which must be unprinted will be removed by a wiper. These cylinder have a large lifetime. Hundreds of thousand of copies are possible in this technique and the speed of the machines can be very high.

A big disadvantage of flexible printing is the environment. However the development is very rapidly these day’s the inks used for flexible packaging is not very well to get in your lungs. Therefore operators should be aware of these facts and use masks to protect themselves.