| 摘要 |
PURPOSE:To maintain or protect the secrecy of printed contents by providing an auxiliary electrode in direct contact with a resistance layer of an ink ribbon at the take-up side, so that the printed contents from which the ink is peeled off after printing through melting of the ink cannot be read with no traces remained. CONSTITUTION:A return electrode 5 is provided opposite to a take-up reel 4, and an auxiliary electrode 6 is placed normally in contact with the outer periphery of an ink ribbon 2 wound up by the take-up reel 4. A printing current I runs to the return electrode 5 from a resistance layer 7 a conductive layer 8 the resistance layer 7 of the ink ribbon 2. When an auxiliary current If is supplied from a driver circuit to the return electrode 5 through the resistance layer 7, conductive layer 8 and the resistance layer 7 of the ink ribbon 2, the temperatures of the heat generated at portion B are raised and accordingly an ink layer 9 at the side of the take-up reel 4 is melted without fail by the above-described currents I and If. Therefore, the traces that the ink was peeled off after printing disappear. Thus, the secret contents can be protected from the eyes of a third party when secrecy is necessary. |
