Offset printing

Offset printing (offset lithography) is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and 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. Ink rollers transfer ink to the image areas of the image carrier, while a water roller applies a water-based film to the non-image areas. The modern "web" process feeds a large reel of paper through a large press machine in several parts, typically for several meters, which then prints continuously as the paper is fed through. Development of the offset press came in two versions: in 1875 by Robert Barclay of England for printing on tin and in 1904 by Ira Washington Rubel of the United States for printing on paper. Rubel's contemporary in Continental Europe was Kašpar Hermann, the author of the offset machine prototype (1904), holder of a patent for an offset disc machine (two rubber transfer rollers facing each other) – rolling-press. In 1907, he successfully started printing in Germany on his Triumph sheetfed offset press.