A method for encoding, on an imprintable medium, identification information for identifying the imprintable medium in a manner detectable by a print-monitoring system includes the steps of defining an identification pattern. The identification pattern is imprinted on a print control region so as to be...http://www.google.com/patents/US6354630?utm_source=gb-gplus-sharePatent US6354630 - Method for embedding non-intrusive encoded data in printed matter
