| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a stamp ink which is used for providing the time of prepar ing documents and gives a print of a seal recognizable without making the documents difficult to see by specifying the hiding ratio of the ink and by facilitating the transfer of the print of a seal to another paper. SOLUTION: This ink has a hiding ratio of 0.95 or lower but pref. 0.02 or higher and can give a print of a seal easily transferable to another paper. The hiding ratio is so low that the characters or drawings of documents are not hidden usually. However, when the recognition of the print of a seal becomes necessary, the hiding ratio is increased by, e.g., chemical changes in color. If necessary, a fluorescent substance is incorporated into the ink to facilitate the recognition of the print of a seal by electromagnetic radiation even on the black ink of documents. This ink is used in, e.g., a new stamp rent system such that a certain organization makes a stamp with a specified face, rent it to a user for a certain time, recovers it, and breaks the face. Thus, the time of preparing documents stamped by the user can be proved.</p> |
