Abstract: Guide rollers are provided to be symmetric with respect to a center of the thermal head. The guide rollers comprise first two guide rollers provided in a vicinity of the thermal head, a guide roller provided in a vicinity of the supply core, a guide roller provided in a vicinity of the take-up core, and second two guide rollers. The second two guide rollers are disposed nearly in a vicinity of the first two guide rollers. The back tension force adding members comprise a fixed brake adding member provided at the supply shaft and an outer peripheral brake adding member for contacting the ink ribbon. The ink ribbon shifting down phenomenon can be prevented. The dirty background and the rubbing transfer phenomenon can be reduced. The aligned winding of the ink ribbon make possible a practical reciprocating ink ribbon cassette. without concern about ink ribbon winding accidents.

Abstract: A combination of a thermal printer and an invertible ribbon cassette has a mechanism for preventing a portion of the inked ribbon extending between a supply core and a take-up core of the ribbon cassette from shifting in the direction perpendicular to the longitudinal direction of the inked ribbon with respect to a printing head. The mechanism includes a substantially planar surface of a platen, and a printing head is urged against the planar surface of the platen through the inked ribbon portion and a sheet to which solid ink in the area on the inked ribbon portion is transferred by the printing head. The width of that area on the inked ribbon portion in the widthwise direction of the inked ribbon is at most equal to a half of the width of the inked ribbon.

Abstract: In a thermal printer having a flat platen, a flat platen support mechanism comprises a flat platen support plate, and a frame body. A projection having a curvature is provided between the flat platen support plate and the frame body. The projection having a curvature is to be swingable freely and to be movable with a slip movement. The projection is arranged on a center line of a flat platen width. When a thermal head is pressed with the flat platen, the flat platen swings smoothly. The thermal head is face contacted uniformly with the flat platen.

Abstract: A thermal head is pressed against a platen consisting of rubber through a recording paper or a heat sensitive paper. The thermal head is provided a head base, a glaze layer portion mounted on the head base, and a heating resistor portion provided on the glaze layer portion. An unit area surface pressure applied from the glaze layer portion of the thermal head to the recording paper or the heat sensitive paper is set to not less than 0.3 kg/mm.sup.2. A hardness of the rubber of the platen is adapted to about Hs 40.degree.-Hs 100.degree.. The high areas of the surface of the recording paper or the heat sensitive paper are flattened to increase the smoothness of the surface of the recording paper or the heat sensitive paper. A high quality printed product of the thermal transfer printer or the thermal printer can be obtained even when the relatively rough recording paper or the heat sensitive paper is used as the object paper.