Offset printing, also called offset lithography, is a method of mass-production printing in which the images on metal plates are transferred (offset) to rubber blankets or rollers and then to the print media. The print media, usually paper, does not come into direct contact with the metal plates.
Offset requires plates that are used to transfer an image onto a rubber blanket and that are rolled onto a sheeting of paper. It is called offset because the ink is not transferred directly to the paper. With digital printing, there are no plates involved and the toner is distributed directly to the paper.