Computer Printers
Unlike typewritten documents, documents made by computerised ink jet or laser printers are rarely identifiable. In some cases, the only expert determinations concerning items made from these printers are that the same typeface design and size (font), letter spacing, and print process were used. Some brands of laser printers do contain small, microscopic dots that contain the serial number of the printer. However, only some law enforcement agencies have the ability to decode these marks, which are largely used to detect counterfeit currency.
In some instances, experts might be able to identify the product used to print a document. Product identification might be possible because some colour printers embed their identification number in some printouts. Similarly, some printers can be identified by minor variants in the way they feed paper through the printing mechanisms.