JPS6434761A - Platen support device in thermal transfer printer - Google Patents

Abstract

PURPOSE:To obtain a platen support device in a thermal transfer printer having superior printing quality without the occurrence of dispersion in printing density and blur, by a method wherein, opposed surfaces of a protruding rib and a platen holding plate are formed into curved shape longitudinally fitting to each other, and the protruding rib and the flat platen holding plate are in point contact with each other at the cross section. CONSTITUTION:A protruding rib 28 and a platen holding plate 29, which are longitudinally mounted on a frame, are formed into curved surfaces opposed to each other. Where the protruding rib 28 has a radius of curvature R and the platen holding plate 29 has a radius of curvature Rp, the curved surfaces are so constructed as to hold a relation of R<=Rp infinity when being projected to a thermal head 3; while Rp<=R infinity when being recessed to the thermal head 3. When a flat platen 19 is pressed by the thermal head 3, the platen hold plate 29 and the protruding rib 28 come into contact with each other first. The platen holding plate 29 having flexibility is easy to change in shape, but the protruding rib 28 having rigidity never changes in shape. In this manner, the platen hold plate 29 and the protruding rib 28 come into contact with each other simultaneously with the pressing to generate a uniform surface pressure on the surface of the flat platen 19.