To obtain an ink which enables truth to be distinguished from falsehood with a sensor capable of suitably detecting when a pattern is printed on a mounting paper by adding a pigment, an additive, and a dispersant to a resin to prepare an ink vehicle and compounding thereinto a composition comprising a colorant exhibiting absorption in an infrared range.
A natural resin, such as rosin or shellac, or a synthetic resin, such as vinyl resin or an acrylic resin, is used as the resin. As the colorant, a colorant, such as a cyanine-, phthalocyanine-, quinone-, or triphenol-based one, exhibiting reflection in the range of 600-670 nm and absorption in the range of 850-950 nm is used. The colorant is compounded in such an amount as not to cause a considerable change in color tone, i.e., 0.5-3.0 wt.%. The ink is used for spot printing in usual printing or is used for printing a pattern as a part of design, and is used for printing gold notes, gift certificates, prepaid cards, etc. In order to enable the ink to be transferred to a thermal transfer paper, the ink containing a colorant exhibiting infrared absorption is applied to a film, etc., to give a thermal ribbon.
UEDA SHUNICHI
TANABE HISAYUKI
HATA KUNIO
NIPPON TOTOR CO LTD