PREPARATION OF CONCEALED DETECTABLE INK IMAGES
Original Publication Date: 1992-Oct-31
Included in the Prior Art Database: 2004-Apr-06
Xerox Disclosure Journal
A liquid ink composition suitable for ink jet printing comprising a liquid vehicle and a colorless fluorescent material is disclosed. The composition may be utilized to prepare concealed ink jet images, which are invisible to the naked eye under visible light, but are detectable under illumination with an ultraviolet light source. Printing concealed ink jet images is useful for document handling and identification, document authentication and recognition, such as barcodes and glyphs, and various security document applications, for example, bank notes, currencies, bonds, stock certificates, and confidential reports. Concealed images may be prepared on a paper or an equivalent substrate using an ink jet printer, for example, continuous and drop-on-demand types, and a liquid ink containing colorless fluorescent dye compounds and optional additives.