there is disclosed a printing apparatus for printing on tags and labels . the apparatus includes a compact housing which is comprised essentially of plastics material . the housing includes a self - storing sliding cover , end plates and a base forming track structure for the cover , and a shelf for mounting a thermal printing mechanism . the printing mechanism is a compact module that is suitably secured in the housing . the printing mechanism includes structure for maintaining tension in a label - carrying web , for adjusting the orientation of the printing mechanism &# 39 ; s thermal print head , and for applying controlled rewinding .