Cautious merchants know that authentic US currency in denominations larger than $10 contains an embedded strip that glows when they hold it under Cautious merchants know that authentic US currency in denominations larger than $10 contains an embedded strip that glows when they hold it under an ultraviolet light. Bills lacking the thread can be identified – and rejected – as counterfeit money. Now scientists at Xerox Corporation have developed a new technology that makes it easier to add that same level of security to any document from a personal check to a birth certificate using the same printers found in most print shops.

The innovative security printing method uses a special combination of toners – the “dry ink” used in xerographic printers – to create the secure imprint. Prints from a four-color printer selectively expose the fluorescent properties found within white paper, making it possible to embed personalized printing, hidden security marks or codes that are only visible when exposed to ultraviolet light.

“What amazes people about the new technology is that we can create fluorescent writing on a digital printer without using fluorescent ink,” said Reiner Eschbach, a research fellow in the Xerox Innovation Group and with principal color scientist, Raja Bala, the co-inventor of the patented process. “That means a four-color digital printer can print everything it normally would, and it can simultaneously individualize a document with a fluorescent identifier.”

The new patented technology belongs to a portfolio of technologies Xerox is developing that build security into documents based on a digital printer’s ability to make any element on the page - lines, text, images - unique to the recipient.

The fluorescent printing is one of several specialty imaging technologies Xerox scientists have developed making it easier for a suspicious recipient to tell which checks, certificates, or other printed materials are authentic. The new specialty technology is part of the Xerox FreeFlow Variable Information Suite 5.0, software that Xerox sells to commercial printers and large enterprises like banks and insurance companies that produce personalized documents.

“Just as US currency has a fluorescent thread to authenticate it, I can imagine a time when your checks will have your signature printed in a fluorescent stripe,” said Eschbach. “A merchant could easily compare the fluorescent signature with the actual one to validate the check.”

The Xerox technology resulted from a “Eureka” moment of inspiration. Eschbach’s group had been involved in the creation of Xerox’s other specialty imaging technologies such as GlossMark imaging, which uses the differential gloss in toner to print a hologram-like image, and he wondered if there was a way to make fluorescent marks with conventional toner.

They realized that paper manufacturers put fluorescent brightening agents in paper to make it appear “white.” Eschbach and Bala discovered certain combinations of toner that would selectively allow the paper’s fluorescence to shine through when exposed to ultraviolet light. Based on this insight, Xerox developed a technology that uses the contrast to “write” fluorescent letters and numbers.

Because the fluorescent marks can be made without fluorescent ink, there are no extra costs for special inks or for additional steps required during printing. Users can embed the security feature as a normal part of their printing process. The fluorescent writing technology is available on Xerox color production printers.

Keywords: Digital printing, Xerox, fluorescent, security printing