| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that printed letters, images, etc. are expanded or shrunk and printing quality is deteriorated in a conventional both-side printing apparatus, which performs printing on both sides of thermo-sensitive paper by using a thermal head, when a perforated line or a folded part passes through one printing unit and changes the speed of the thermo-sensitive paper by the resistance or shock thereof, and the influence thereof affects the speed of the thermo-sensitive paper at the other printing unit. SOLUTION: Each of the pair of the printing units 2 and 3 for performing printing on both the upper and lower sides individually has a driving system composed of a platen roller of the printing unit, a motor, a belt, a gear, etc. , and the thermo-sensitive paper is caused to be loose between the pair of the printing units. As a result, even when the speed of the thermo-sensitive paper is varied when the perforated line or a folded part passes through one of the printing units, the variation is not transmitted to the other printing unit through the driving systems of the platen rollers 6, 7 or the thermo-sensitive paper itself. Thus, the printing quality is not deteriorated. COPYRIGHT: (C)2007,JPO&INPIT
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