Thermal head

• US 5,635,975 A
• Filed: 09/13/1996
• Issued: 06/03/1997
• Est. Priority Date: 07/26/1994
• Status: Expired due to Term

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Terao, Hirotoshi, Sagawai, Shinichi, Shirakawa, Takashi, Nakatani, Toshifumi
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): ANDERSON, LYNNE D
• Application Number:
  US08/713,976
• Time in Patent Office: 263 Days
• Field of Search: 347/200, 347/202, 347/205, 347/206, 347/208
• US Class Current: 347/208
• CPC Class Codes: B41J 2/3357 Surface type resistors

Abstract

A thermal head which can effectively use a thin film ribbon as an ink ribbon, and take a relatively long edge distance. The thermal head has its object to maintain transferring property of the ink to a recording medium and to maintain high printing quality for a long period of time. A heating portion is formed from the top of a heat insulating layer to a slope of the common electrode side of the heat insulating layer, and a gap is formed on the common electrode. The ink ribbon is pressed into contact with the recording medium at a portion of low-temperature of the top of portion of the heat insulating layer falling outside the center portion of the heating portion where a pressure of the printer to the platen is mainly applied.

Claims

1. A thermal head comprising:

a substrate;

a heat insulating layer formed on said substrate, the heat insulating layer including a protruding portion having an upstream sloped side, a downstream sloped side and a top portion extending between the upstream sloped side and the downstream sloped side;

a plurality of individual electrodes, each of the plurality of individual electrodes formed on said heat insulating layer and extending up the downstream sloped side to the top portion of the protruding portion; and

a common electrode formed on said heat insulating layer and extending to the upstream sloped side of the protruding portion;

wherein a plurality of heating portions are exposed between the plurality of individual electrodes and the common electrode, each of the plurality of heating portions extends from the top portion of said protruding portion and down the upstream sloped side to said common electrode.

2. A thermal head according to claim 1, wherein said plurality of individual electrodes is extended to an uppermost portion of the top of said heat insulating layer.

3. A thermal head according to claim 2, wherein a slope of said heat insulating layer of said upstream sloped side is located under an imaginary line segment connecting an end portion of said common electrode and the top portion of said insulating layer so as to form a gap.

4. A thermal head according to claim 1, wherein a slope of said heat insulating layer of said upstream sloped side is located under an imaginary line segment connecting an end portion of said common electrode and the top portion of said heat insulating layer so as to form a gap.

5. A thermal head for a thermal transfer printer, the thermal transfer printer including a platen and means for moving the thermal head in a printing direction relative to the platen, the thermal head comprising:

a substrate;

a heat insulating layer formed on said substrate, the heat insulating layer including a protruding portion having a first sloped side located upstream in the printing direction, a second sloped side located downstream in the printing direction and a top portion extending between the first sloped side and the second sloped side;

a plurality of individual electrodes, each of the plurality of individual electrodes formed on said heat insulating layer and extending up the second sloped side to the top portion of the protruding portion; and

a common electrode formed on said heat insulating layer and extending to the first sloped side of the protruding portion;

wherein a plurality of heating portions are exposed between the plurality of individual electrodes and the common electrode, each of the plurality of heating portions being located on the first sloped side of the protruding portion.

6. A thermal head according to claim 5, wherein said individual electrode is extended to an uppermost portion of the top of said heat insulating layer.

7. A thermal head according to claim 6, wherein a slope of said heat insulating layer of said upstream sloped side is located under an imaginary line segment connecting an end portion of said common electrode and the top portion of said insulating layer so as to form a gap.

8. A thermal head according to claim 5, wherein a slope of said heat insulating layer of said upstream sloped side is located under an imaginary line segment connecting an end portion of said common electrode and the top portion of said heat insulating layer so as to form a gap.