Signature protected photosensitive optically variable ink compositions and process
First Claim
1. An aqueous ink capable of providing a secure marking including a dark, machine-readable image exhibiting fluorescence when exposed to fluorescent-exciting radiation, said ink being of suitable viscosity and surface tension for use in ink jet printing, comprising:
- (a) a first colorant comprising a fluorescent dye and/or pigment emitting light within a characteristic emission band when excited by fluorescent-exciting radiation;
(b) a second colorant comprising a dye and/or colloidal pigment having a light absorption band overlapping with or at longer wavelengths than the characteristic emission band of the first colorant, in such a way as to result in a dark color, (c) a third component comprising a fluorescent/phosphorescent rare earth composition in a detectable amount effective for security identification, and (d) an aqueous liquid vehicle comprising water and a water-soluble vehicle in sufficient amounts to achieve an ink viscosity and surface tension effective for application of the ink to a substrate in a predetermined pattern by ink jet printing.
2 Assignments
0 Petitions
Accused Products
Abstract
Signature protected photosensitive optically variable (POV) inks are provided, which are capable of providing a unique signature in addition to other security features of POV inks. The inks contain at least two types of colorants, and a third, signature component and other ingredients to enable printing. A first colorant comprises a fluorescent dye and/or pigment emitting light within a characteristic emission band when excited by fluorescent-exciting radiation. A second colorant comprises a dye and/or pigment having a light absorption band at overlapping or longer wavelengths than the characteristic emission band of the first colorant in such a way as to result in a dark color. The third component is a fluorescent/phosphorescent rare earth composition. The inks give dark visible ink images, which also produce detectable coincident fluorescent and phosphorescent images. The inks can be used with detectors of red phosphorescence to achieve a new level of security in high speed sorting operations.
63 Citations
20 Claims
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1. An aqueous ink capable of providing a secure marking including a dark, machine-readable image exhibiting fluorescence when exposed to fluorescent-exciting radiation, said ink being of suitable viscosity and surface tension for use in ink jet printing, comprising:
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(a) a first colorant comprising a fluorescent dye and/or pigment emitting light within a characteristic emission band when excited by fluorescent-exciting radiation;
(b) a second colorant comprising a dye and/or colloidal pigment having a light absorption band overlapping with or at longer wavelengths than the characteristic emission band of the first colorant, in such a way as to result in a dark color, (c) a third component comprising a fluorescent/phosphorescent rare earth composition in a detectable amount effective for security identification, and (d) an aqueous liquid vehicle comprising water and a water-soluble vehicle in sufficient amounts to achieve an ink viscosity and surface tension effective for application of the ink to a substrate in a predetermined pattern by ink jet printing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification