NCJ Number
153111
Journal
Journal of Canadian Society of Forensic Science Volume: 27 Issue: 4 Dated: (December 1994) Pages: 245-259
Date Published
1994
Length
15 pages
Annotation
This test compared laser-printed or photocopied documents by using a combination of analytical instruments.
Abstract
Thirty-six different laser-printed and photcopied documents were obtained from office equipment manufacturers and from a photocopier toner databased maintained at the RCMPolice Central Forensic Laboratory, Ottawa. The instruments used for testing were the stereomicroscope, FTIR Spectroscopy, Scanning Electron Microscope, and Energy Dispersive X-ray. The documents were first examined microscopically to use oblique lighting and a magnification range of 30 to 50x. They were examined for such features as fushion method, trash marks, roller defects, and print quality. After the initial microscopic examination, two samples were taken from each document for analysis by FTIR and SEM/EDX. Although a document can be identified to the machine that produced it, in the absence of a suspect machine and non- machine-related trash marks (i.e., staple marks, inserted writings, etc.), it is difficult to determine whether a questioned document was produced by a photocopier or by a laser printer. Confocal Laser Scanning Microscopy or carbon classification may provide solutions to this problem. Quantitative analysis may also permit chemically similar toners to be distinguished from batch-to-batch variances of a single toner product. 9 figures and a 13-item bibliography