We can locate the location of printing just by analysing the xerox print(Forensic identification)

Similar to forensic identification of typewriters, computer printers and copiers can be traced by imperfections in their output. The mechanical tolerances of the toner and paper feed mechanisms cause banding, which can reveal information about the individual device's mechanical properties. It is often possible to identify the manufacturer and brand, and, in some cases, the individual printer can be identified from a set of known printers by comparing their outputs.
Some high-quality color printers and copiers steganographically embed their identification code into the printed pages, as fine and almost invisible patterns of yellow dots. Some sources identify Xerox and Canon as companies doing this. The Electronic Frontier Foundation (EFF) has investigated this issue and documented how the Xerox DocuColor printer's serial number, as well as the date and time of the printout, are encoded in a repeating 8×15 dot pattern in the yellow channel. EFF is working to reverse engineer additional printers. The US government has been reported to have asked these companies to implement such a tracking scheme, so that counterfeiting can be traced.

Printer steganography is a type of steganography produced by color printers, including HP, Xerox and Epson brand color laser printers, where tiny yellow dots are added to each page. The dots are barely visible and contain encoded printer serial numbers, as well as date and time stamps.
Color laser printers appear to be the type mostly involved, the measure being brought in during the 1990s by companies such as Xerox seeking to reassure governments that their printers would not be used for the purposes of forgery. The identification is by means of a watermark, often using yellow-on-white, embedded in the printout of each page, and in conjunction with other information can be used to identify the printer which was used to print any document originally produced on a wide range of popular printers. It may be actual text, or a repeated pattern of dots throughout the page, more easily visible under blue light or with a magnifying glass, and is intended to be very difficult to notice with the naked eye.
In 2005, the Electronic Frontier Foundation cracked the codes for DocuColor printers and published an online guide to their detection.Most printers' codes have not been decoded, although the coding system framework and printer serial number encoding is the same on both DocuColour and the Epson Aculaser C1100/C1100N/A and possibly many more Epson lasers.





An illustration of printer stenography—yellow dots that many color printers produce to encode printing date, type of printer and printer ID.