Patent ID: 8133647

Claim:
A black toner formulation comprising: a binder; an infrared absorbing black colorant at a concentration of 0.25-2.0% by weight; and a plurality of infrared transmissive colorants other than an infrared transmissive black colorant configured to provide a black color, wherein said plurality of infrared transmissive colorants comprise two or more of the following: blue pigment, cyan pigment, green pigment, yellow pigment, orange pigment, brown pigment, red pigment, magenta pigment and violet pigment; wherein the toner formulation indicates the following spectral characteristics when fused on white paper at a L* value of 9-24: % R 800-1200 nm ≧(0.00082× R vis+0.0078)(λ)+1.98 R vis−9.6 and % R 800-1200 nm ≦(0.00082× R vis+0.0078)(λ)+1.98 R vis+10.0 wherein % R 800-1200 nm is the percent reflectance for a given wavelength (λ) in the range 800-1200 nm, Rvis is the average percent reflectance of the fused toner formulation for the 380-730 nm region of the spectrum, and the value of % R 800-1200 nm at said given wavelength is less than or equal to 70%; and wherein the toner formulation has a chroma C* of less than or equal to 15.0 for all half-tone shade levels printed on white paper.