Patent ID: 8629414

Claim:
A method for detecting an overcoated image and for protecting an underlying ink-based or toner-based image, comprising: providing a clear ink suitable for printing comprising an ink vehicle, and an ultraviolet absorbing additive; providing a substrate having an ink-based or toner-based image; wherein the substrate comprises an optical brightener; printing the clear ink over the ink-based or toner-based on the substrate to create a protective, overcoated image conferring scratch and smear resistance to the ink-based or toner-based image; exposing the substrate to an ultraviolet light source, thereby activating the optical brightener in the substrate to create a contrast image between the substrate and the overcoated image; evaluating the substrate for any activation of the optical brightener creating the contrast image to detect the presence of the ultraviolet absorbing additive in the overcoated image.