Rotary printing press
From Wikipedia, the free encyclopedia
A rotary printing press is a printing press in which the impressions are curved around a cylinder so that the printing can be done on long continuous rolls of paper, cardboard, plastic, or a large number of other substrates. Rotary drum printing was invented by Richard March Hoe, and then significantly improved by William Bullock
Specific wallpaper printing machines, using mostly wooden printing cylinders, have been widely used throughout Europe.
Today, there are three main types of rotary presses; offset, rotogravure, and flexo (short for flexography). While the three types use cylinders to print, they vary in their method.
Offset lithography uses a chemical process which an image is chemically applied to a plate (generally through exposure of photosensitive layers on the plate material).
Gravure is a process in which small cells or holes are etched into a copper cylinder which is filled with ink.
Flexography is a relief system in which a raised image is created on a typically polymer based plate.
In stamp collecting, rotary-press-printed stamps are sometimes a different size than stamps printed with a flat plate. This happens because the stamp images are further apart on a rotary press, which makes the individual stamps larger (typically 1/2 mm to 1 mm).
