| 摘要 |
<p>PROBLEM TO BE SOLVED: To permit the prevention of forgery by duplicating machine surely by a method wherein a first printing layer, having a pattern constituted of arbitrary printing elements, is formed on a printing substrate with yellow based printing ink, then, a second printing layer, having an arbitrary pattern printed by blue based printing ink, consisting of inorganic pigment and provided with transparency, is formed on the first printing layer. SOLUTION: A printed matter, constituted of first and second printed layers, becomes visually green color, corresponding to a color formed of a blue based printing ink, consisting of inorganic pigment forming an upper layer 3 and having transparency, and yellow based ink, forming a lower layer 2, or the green color, corresponding to the thickness of ink films of these two layers, while a latent image 2 can not be seen visually. However, when the copy 4 of the printed matter is produced by a color copying machine, the information, provided with a normal yellow based ink forming the lower layer 2, is duplicated and developed as a yellowish remarkable image even when the adjustment of concentration is effected through color adjusting function possessed by the color copying machine since the blue based printing ink, forming the upper layer 3, is prominent in light transmission properties.</p> |
