Flexoprinting (flexo-graphic printing)

Advantages of flexo printing:

• fast production ramp-up
• short set-up times
• screen resolution up to 60 L/cm
• U.V. inks, solvent-based inks, water-based inks
• good ink-coverage, high brilliance
• up to 8 colours
• almost offset quality with flexo CtP ( computer-to-plate system)
• printing width up to 330 mm
  

Flexo printing is similar to letterpress or relief printing. The main difference between these methods is found in the greater elasticity of the plates. As a result of this a lower printing impressure is required to transfer the image to the substrate. Thus making it possible to imprint a larger variety of substrates. The inks used for flexo printing are more viscid than the ones for letterpress printing. The advantage of lower viscosity means that the design of flexo inking units is less complex than letterpress printing.  Anilox rollers are used for the inking of flexo plates. The task of these rollers is to transport a certain amount of ink onto the plate’s surface. The amount of ink used is determined by the texture of the anilox roller. A dip roller that rotates within an ink trough, or with an inking unit directly attached to the anilox roller, provides the ink supply for the printing process.

U.V. flexo printing
A special feature of flexo printing is the U.V. printing ink. While solvent- and water-based inks dry physically due to vaporisation, U.V. ink is cured (i.e. dried) by a polymerisation caused by U.V. radiation. The cure of U.V. ink only takes a fraction of a second. This reduction in the curing speed reduces or even eliminates typical phenomenons of flexo printing, for example dot fringe and dot gain. At the same time it facilitates the imprinting of delicate materials such as synthetics or metallized foils.