Problems of Forensic Sciences 2001 Vol. 46 (XLVI) 356-374
EVIDENTIAL VALUE FROM INK-JET PRINTERS
Stephen Philip DAY, Lee SHUFFLEBOTTOM
Forensic Science Service, Huntingdon, United Kingdom
Streszczenie
The widespread use of ink-jet printers has made it necessary for document examiners to find a method of linking a questioned document to an individual ink-jet printer. The identification and characterisation of defects produced by ink-jet cartridges provides a means of achieving this. This study was primarily to investigate the physical nature of defects in inkjet printers and show how printer outputs and printers can be linked. Thus it was hoped to establish whether or not ink-jet printers can be linked to their print-outs through their physical appearance on the paper and if so to estimate the evidential value of any defects or other physical features. By identifying such features it was hoped that a protocol for the examination of this type of printer could be developed. Defects can be easily introduced into printouts by blocking the electrical defects that control a particular print-head. The behaviour of the defects thus produced is different for different types of ink-jet print cartridges. By studying the behaviour of such defects it is possible to devise a strategy for the examination to distinguish between different printers. Not all nozzles get blocked with the same frequency so if a particularly rare nozzle gets blocked then the evidential value in linking that particular printer to the printout will increase.
Słowa kluczowe
Ink-jet printers; Document examination; Printing defects; Officemachinery.