تسجيل الدخول

تسجيل

LASER PRINTERS AND COPIERS

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p531-532

2026-08-25

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LASER PRINTERS AND COPIERS

Laser printers and copy machines that use Xerography do not use ink to make char acters on the paper. Instead, the characters are made using a toner made from finely divided carbon powder and binders and a laser. There is little chance that characters will become deformed over time. If the cartridge that contains the toner starts to run out, then the print quality may become irregular, but this will change with time and may not be of much help. There are situations, however, where extraneous marks or blotches of toner may show up repeatedly in the same location until the machine is cleaned or repaired. If the questioned document and exemplars both show these same markings in the same location on the copy, this may provide individual information about the source of the questioned document. It would not be necessary for the examiner to have the printer or copier. Instead, whoever investigates the incident should make sure that an adequate number of exemplars are taken to show the degree of consistency of the extraneous markings. If there are no reproducible, extraneous markings on the paper, and the source of the copy is not known, it may still be possible to determine the make of the copier or printer by chemical analysis and com parison of the toners with known samples. This evidence is not individual, however; it is normally not possible to determine with certainty that a particular machine was the source of a questioned document.