Flexo printing is a widespread printing technology that is most often used for printing flexible and transparent materials, as well as for designs that require high ink transfer.
Flexographic printing in Rotoprint
Rotoprint is one of the first print providers in Bulgaria that implemented flexographic printing technology and applied it to high-quality label printing.
Rotoprint has several flexo printing presses with different configurations, which allows us to be extremely flexible in printing different orders and designs.
In addition to the presses themselves, we use the highest quality flexo printing plates, which allow us to print at a very high quality. It is closing the quality gap with gravure and offset printing. In practical terms, the typical artifacts you would get from most printers using flexography are absent on the Rotoprint’s jobs. They are almost unnoticeable or nonexistent thanks to Kodak NX photopolymer plate production technology.
Applications of flexographic printing
Flexographic printing has a very wide application on various materials, but it is most often used for printing on transparent materials or designs that need opaque colors, for example, a white background and the like.
Flexographic printing plates are very stable over time and can be stored, making them very suitable for long runs or for runs that will be reordered several times over time.
How does flexography work?
Flexography is a method of transferring ink onto printing media using a combination of:
An ink roller that takes ink from an ink container
A special cylinder with small holes, which is called anilox
A thin strip, usually of metal, which is called a squeegee
Flexible polymer plate, resembling a slightly transparent rubber, which is also called flexo cliché
In terms of its inner workings, the flexographic printing section is much simpler than the offset one. By its very nature, flexo printing is letterpress, which means that the form that transfers the ink has a raised relief, and the raised parts are the ones that take ink.
The cliché is a monomer of a certain thickness. Using UV light and a combination of film or direct exposure, this cliché is polymerized in certain places, which become hard. The hard elements become the printed elements, and the soft elements are removed.
The ink roller takes ink from the ink container and applies it generously to the anilox roller. Aniloxes have holes of different shapes and sizes, which controls the ink transfer - if we want a lot of ink - we put anilox with large holes (high transfer).
The anilox is then passed through a flat plate called a squeegee, the function of which is to remove excess ink from the anilox and leave ink only in the pinholes, like spreading a very thin layer of butter on a slice.
The anilox then transfers a controlled amount of ink to the raised elements of the cliché, which transfers the image directly to the printing material.
The technology itself has developed significantly in recent years, significantly reducing the quality gap significantly with the offset printing. There are still printers where you can see flexo-specific artifacts. With Rotoprint they are eliminated or unnoticeable because of the modern technologies we use.