Understanding Flexographic Printing Principles

What is flexographic printing? 

The fastest growing conventional process of printing particularly for packaging materials such as flexible films, corrugated containers or hard cardboard is known as flexography. Flexographic printing is a letter press type of printing where the printing plate is of a soft material. By producing a positive reflected master of the target image as a three-dimensional relief in a polymer or rubber material, a flexographic print is subsequently made.

view of printed equipmentThe Flexographic Printing Process

The flexographic printing plates can make use of digital and analog platemaking processes. On the polymer or rubber plate, the image areas are set up above the non-image areas. The ink- low viscous type, is transferred by the ceramic or anilox roller to the plate from the ink roll that is immersed partially in the ink tank. The anilox roller’s texture holds a specific amount of ink as it is covered with thousands of small cups that allow it to measure the ink going to the plate in a uniform and even thickness quickly. 

Color Rendering

The four elemental colors of cyan, magenta, blue, black and the special or ornamental colors which include silver, white, gold or green are printed one after the other. Single solid color as well as multi-color halftones can be printed. What controls the amount of ink transferred to the printing plate is the makeup of the anilox roller. Smudgy or lumpy effects can be avoided if the amount of ink that has been transferred to the printing plate is not excessive. If the ink supply is on but the impression cylinder is off, drying of ink in the cells may be prevented by keeping the anilux roller turning. 

Set of balls isolated on black: CMYK colorsThe Flexographic Print Unit

The print unit consists of the following components:

  • Soft printing plate
  • Anilox roller
  • Impression cylinder
  • Plate cylinder
  • Printing substrate
  • Inked up substance
  • Ink supply or the chambered doctor blade system
  • Cells of the anilox roller filled with ink
  • Elastic printing plate with raised elements

Machine Elements And Features

Flexographic printing presses for liquid container and label printing have the following elements and features:

  • Modular construction allowing for a combination of different printing methods using the same machine
  • Low web speed in label printing
  • Low degree of automation
  • Drives and automation have to cover the exchange of print deck mechanics

Pile of Various newspapers over white background.Printing Advances

Flexographic printing has also made significant advances in printing publication materials such as the newspapers. With the continuous improvement in the quality of flexo printing, the printing tasks are expanded to spot color on a wide array of substrates. 

Flexograph-Printed Products

Products that use flexographic printing include corrugated containers, cardboard such as liquid container or boxes, flexible packaging materials such as plastic/plastic bags, bags, foil, labels on bottles, acetate film, milk cartons, candy bar wrappers, and brown paper such as paper bags, envelopes or wrapping paper.

 

What other products do you know are printed by a flexograph printing machine?