Patent ID: 7645560

Claim:
An image forming medium, comprising a substrate; and an imaging layer coated on or impregnated into said substrate, wherein the imaging layer comprises an imaging composition comprising a photochromic or photochromic-thermochromic material and an infrared absorbent dissolved or dispersed in a solvent or polymeric binder; wherein: the photochromic or photochromic-thermochromic material and the infrared absorber are selected so that: the infrared absorber absorbs infrared light of a wavelength in a range from about 730 nm to about 1500 nm; the imaging composition is imageable by light of a first wavelength and erasable in a short time period by a combination of infrared radiation and light of a second wavelength, and exhibits a reversible transition between a colorless and a colored state; and the short time period is the time period for the maximum absorbance of the imaging composition in the region 400-800 nm to be reduced from its initial absorbance to one half of the initial absorbance, in about 10 seconds or less.