Patent ID: 8349211

Claim:
A fluorescent inkjet composition, comprising: a visible ink composition including a visible colorant, wherein said visible colorant is detectable in a visible spectrum, and present at about 0.5% to about 10% by weight of the fluorescent inkjet composition; and a fluorescent dispersion including an invisible fluorescent colorant; wherein said invisible fluorescent colorant absorbs light having a wavelength of 250 to 400 nm, emits light in the range of 450 to 700 nm, and is invisible to incident light in the visible spectrum of 380 to 750 nm, wherein said invisible fluorescent colorant is present between 0.01% to 1.5% by weight of the fluorescent inkjet composition, and wherein said fluorescent inkjet composition emits light at a first intensity I 1 in the range of 450 nm to 700 nm upon excitation by incident light having a wavelength in the range of 250 to 400 nm and said fluorescent inkjet composition is capable of emitting light at a second intensity I 2 upon exposure to a temperature of 60° C. for 8 weeks, wherein I 2 =(0.50 to 1.0)* I 1 .