Elcography

A digital printing process invented in 1971 by Adrien Castegnier which uses the electrochemical effect of electrocoagulation. The water-based inks that are used contain soluble salts, polymers and ink pigments. An elcography system consists of a rotating impression cylinder made from stainless steel and a strip of tightly positioned electrodes (located close to this cylinder) which extends over the printing width. Ink applied in a thin layer between the cylinder and the printing strip coagulates and sticks to the cylinder when current is applied to the latter by an electrode. Controlling the electrodes in this way results in a print image on the cylinder. The remaining liquid ink is removed from the surface of the cylinder. The coagulated ink is then applied to the printing stock which is pressed onto the impression cylinder by a transfer drum. Elcographic presses currently have a resolution of 400 dpi and 256 levels per color.

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