Hitachi, Ltd.

Ryooichi Kobayashi

Akira Sasaki

Masafumi Suzaki

Katsumasa Mikami

Tomoji Kitagishi

Yousuke Nagano

Shigetaka Furukawa

Fumio Takahagi

Akiyoshi Hakoyama

Takeo Honma

Yoshihito Takahashi

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. Alternatively, the mechanism includes a detector mechanism operative in response to the variation in diameter of the inked ribbon wound on the supply core for applying a variable back tension in the reverse direction to the tension acting on the inked ribbon portion by the take-up core.

Thermal printer and invertible ribbon cassette therefor including a

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.

Printer having a thermal head

A thermal trasfer printer including a thermal head, and a platen positioned against the thermal head through a printing sheet. The thermal head has a substrate formed of heat insulating material, at least one glaze layer on a top surface of the substrate extending longitudinally thereof, a plurality of heat generating elements on the glaze layer, a plurality of electrodes each connected to the heat generating elements in a manner to form an opening for the heat generating elements and a protective layer for preventing the electrodes and heat generating elements from contacting the printing sheet to avoid their wear. A portion of the protective layer for protectng the heat generating elements has a height which is greater by more than 5 .mu.m than the height of a portion of the protective layer for protecting the electrodes. The width of the glaze layer transversely of the substrate is less than 200 .mu.m at a location which is 10 .mu.m below a top surface of the portion of the protective layer for protecting the heat generating elements in a vertical direction. The platen is a flat platen and its deflection caused to occur by a biasing force exerted on the thermal is more than 0.02 time and less than twice as great as the height of the glaze layer.

Thermal print head

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Hitachi, Japan

Ryooichi Kobayashi