Printing unit having a plate cylinder and plate changer

A printing unit having a printing forme cylinder (04), wherein a plate changer (14) is provided, assigned to the printing forme cylinder (04), wherein the plate changer (14) has a bearing surface (16) on which a printing forme arranged or to be arranged on the printing forme cylinder (04) can be placed, wherein this bearing surface (16) is arranged such that it can be moved back and forth longitudinally with respect to the rotational axis of the printing forme cylinder (04) between at least two defined positions, characterized in that the printing forme is arranged true to register on the bearing surface (16) of the plate changer (14), wherein at least two edges of a carrier of the printing forme in question, which are disposed at right angles relative to one another, are brought into physical contact with register pins arranged on the bearing surface (16) of the plate changer (14), wherein a first edge of the carrier of the printing forme in question is disposed so as to strike a first register pin and a second edge of the carrier of the printing forme in question, orthogonal to the first edge, is disposed so as to strike a second register pin, wherein the printing forme resting on the bearing surface (16) is held there on the bearing surface (16) of the plate changer (14) by a magnetic holding force, wherein at least one plunger having a direction of action directed opposite the magnetic holding force is provided, with which at least one plunger at least one end of the printing forme held on the bearing surface (16) of the plate changer (14) and facing toward the printing forme cylinder (04) can be released from this bearing surface (16) and can be transferred to the printing forme cylinder (04).