Abstract: A principal object of the invention is to provide an improved marking apparatus capable of clearly marking desired information at the same relative location on a succession of rapidly-moving, heat-sensitive articles. Prior art marking devices employing heated printing heads presented problems when employed to mark in this manner. These problems became accute where the printing extended over any significant distance in the direction of travel.The apparatus, shown generally as 10 in FIG. 1 is of the type comprising an electrically-heated marking head 12, a backup means 14 positioned opposite the marking head, and means 16 for reciprocating the marking head between a withdrawn position and a marking position adjacent to said backup means. A specific improvement according to the invention is the imparting elliptical motion of the printing head which enables contact times sufficient for clear marking at linear rates of greater than 1500 inches per minute.