| 摘要 |
PURPOSE:To make divulgence of confidential documents prepared at an office difficult by providing a device for printing documents in color which cannot be duplicated by a duplicator. CONSTITUTION:An ink ribbon bearing light-blue ink is used instead of an ink ribbon bearing a conventional black ink, and the ink ribbon is hammered using fine wire to print characters. If characters are duplicated using paper containing printed characters with a commercial duplicator, almost all printed characters are not duplicated or even duplicated characters are not clear. Documents printed in light blue or yellow using a printer with a device to print in either one of these colors cannot be duplicated with a common duplicator or are duplicated but with very poor print quality. Thus almost no secret is divulged from confidential documents prepared at an office. |
