| 摘要 |
<p>PURPOSE: To provide securities protected from reproduction over a wide range of set values of a copying machine and prevented completely from modification using a desk editing device completely. CONSTITUTION: In improved securities, the reproduction of a document by a color copying machine is prevented. The document is provided with cancellation sentences 32, 36 by two color tones and a background pattern. When the copying machine is adjusted in order to make the cancellation sentence of a copy reproduced in one color tone unclear, a cancellation sentence in a different color tone appears. In another example, the densities of the cancellation sentence and the background pattern change over the surface of the document. In this case, the cancellation sentence appears somewhere on the copy irrespective of the adjustment of the copying machine.</p> |
