Abstract: A marking machine for automatically marking cartons passing on an intermittently moving conveyor includes a printing head cyclically moved by a pneumatic cylinder into engagement with the cartons. The motion of the printing head is controlled by guide elements extending from the printing head cooperating with slots in adjacent side plates. The printing head passes durng its cyclical movement across an ink roll disposed above the side plates. A backer plate drops behind the carton surface to be marked just before the printing stroke of the print head. The movement of the backer plate is provided by the guide elements extending from the printing head. The type face on the printing head can be oriented to face upwardly for marking the side of the cover of an egg carton or be oriented to face downwardly for marking a separator in a filler flat.