| 摘要 |
PURPOSE:To make it possible to use a black ink ribbon and a monochromatic color ink ribbon by the same ribbon cassette and to reduce the cost of the ink ribbon, by controlling printing operation by detecting the finish of the ink ribbon when the output of a sensor changed three times during a time when the ink ribbon is fed by definite quantity. CONSTITUTION:A light impervious tape 3 connects a leader 2 having black color parts and transparent parts arranged thereto at an equal interval and a black ink ribbon 1 or a monochromatic color ink ribbon 4. When the matter present in the groove part of a ribbon end sensor 7 detecting that the ink ribbon was finished transmits light, output comes to 'H' and, when transmits no light, the output comes to 'L.' A printing control part C judges that the ink ribbon was finished when the output of the ribbon end sensor 7 changed three times during a time before a capstan roller 11 sends the ink ribbon by (l) from the point of time when the output of said sensor 7 changed at first to stop printing operation. (l) is a length such that l>a+b and l>2b are formed when the width of the tape 3 is set to (a) and the width of the black color part or transparent part of the leader 2 is set to (b).
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