A matrix printing apparatus of the type having a path for sequentially transporting a series of documents to be printed between a plurality of dot matrix ballistic print heads and back-up platen rollers opposite each print head, the dot matrix ballistic print heads adapted, when actuated, to simultaneously impact an ink source and one side of each document as each document passes the print heads to apply printed material to each document in a pre-programmed array. The improvement of the present invention comprises moving the back-up platen rollers from a first position adjacent the print head when the print head is actuated, to a second position at a distance from the print head when the print head is not actuated. The matrix printing apparatus also includes an ink source comprising an endless inked ribbon which continually moves between the dot matrix ballistic print heads and the document path, and includes an ink guard disposed between the inked ribbon and the document path, the ink guard having relatively small apertures therein adjacent each print head wherein only the portion of the ribbon adjacent each print head extends through each corresponding aperture and contacts each document during application of printed material to each document.