15th EditionAppendix A : Design and Production—Basic Procedures and Key Terms
Principle of offset printing. A plate is wrapped around and fastened to the plate cylinder. Water applied by the dampening rollers adheres only to the background area of the plate; ink applied by the inking rollers adheres only to the dry image of the type on the plate. As the plate cylinder revolves, it transfers the ink to the rubber blanket of the blanket cylinder, which in turn transfers (or offsets) it onto the paper, which is held in place by the impression cylinder.