Wednesday, 26 October 2011

WIDFP? - Rotary Printing

In this process the image printing plates are wrapped around a cylinder. This is an automated print process and the material to be printed can be sheet fed or on a roll.

The 3 main types of rotary printing are:

  • Offset Lithography, (litho)
  • Rotogravure (gravure)
  • Flexography (flexo)

Offset Lithography
Etched aluminium plates wrapped around a cylinder transfer ink to an 'offset' rubber blanket roller and then to print surface. Sheet fed or Web fed.

Typical 'WEB offset' machine. Most web machines are incredibly high speed and run 'rolls' of material as opposed to sheet fed. Often have finishing and folding built into the machine.


Offset printing is a commonly used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a water-based film (called "fountain solution"), keeping the non-printing areas ink-free.

Development of the offset press came in two versions: in 1875 by Robert Barclay of England for printing on tin, and in 1903 by Ira Washington Rubel of the United States for printing on paper. (link)

Copper plates (with mirror image) transfer ink directly to print surface, usually on rolls.
Advantage, plates are more durable and so are good for long print runs.


A positive, mirror image rubber polymer plate, on a cylinder, transfers 'sticky' ink directly to print surface. Usually roll feed.

Flexo plate. Rubbery/silicone feel with the image raised 2-4mm.


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