Here at The Polythene Company we print custom designs with artwork ranging from simple text, to highly detailed pictures. We thought we’d give you an insight into just how we make your artwork come to life.
It all starts with you. You send us your desired artwork and we then transform this into a ‘proof’ our plate makers use to design the printing ‘plates’ that we use for making the bags. We can print designs in up to 8 colours using the flexographic print process. Once this has been checked for accuracy and to ensure that there will be no issues with your design, the plates are made.
Just what are ‘printing plates’?
Printing plates are how we transfer the printing ink onto the film that makes the bags. These flexographic plates are made out of a light-sensitive polymer. The design is then created on this plate using UV light to harden the polymer in the design areas.
How do the plates work?
One plate is needed for every colour to be printed. The plates are mounted onto a cylinder which is placed in the printing press. Every colour has to align perfectly with each other to make sure the design is printed properly, or in “register”. After this, the ink is transferred from the ink roll which is flood-coated with ink. It then transfers to the ‘anilox’ roller which holds a specific amount of ink on the surface as it is covered with thousands of small wells that enable it to transfer ink to the printing plate in a uniform thickness evenly and quickly.
How does the ink adhere to the surface of the polymer film and not rub away or crack?
Our film is specially treated using a method called Corona treatment. This treatment involves using a high frequency discharge that increases the adhesion of a plastic surface on one side. This side is the side used for printing on. The ink will then adhere to the polythene film and not rub off, crack or fade.
The printing is then complete!
The film is always printed before conversion, so once the film has been run through our printing machines it is then ready to be taken across to the conversion machines. The conversion machines then turn the film into your polythene bags.