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NCJ Number: 77363 Find in a Library
Title: Defect Marks and the Identification of Photocopying Machines
Journal: Journal of the Forensic Science Society  Volume:21  Issue:1  Dated:(January 1981)  Pages:23-30
Author(s): R N Totty; D Baxendale
Date Published: 1981
Page Count: 8
Format: Article
Language: English
Country: United Kingdom
Annotation: This British article explains how forensic scientists can examine photocopies to determine their origin and the type of machine used to make them by assessing evidence available from an analysis of the paper or toner and from marks on the paper arising from defects in the copier mechanism.
Abstract: The use of copies offers a number of advantages to persons engaged in certain types of crime. Examples of cases include anonymous letters, leakage of confidential information, false insurance certificates, and the preparation of composite documents from parts of various genuine documents. Photocopy processes are explained in detail. The two main categories of processes are the direct process and the indirect process. Any examination of copies must start with a determination of which of these two processes was used. Other steps in the examination include a chemical analysis of the toner and a comparison of defect marks in the photocopy process. The discussion concludes that glass defects are the only permanent defect marks on a copier that will be consistently reproduced on copies. While the presence of the same defect on two documents will indicate common origin, the absence of a defect on one, although present on the other, does not necessarily indicate that the documents were copied on different machines. The interpretation of the absence of defects from particular documents must be approached with caution and requires a detailed knowledge of the mechanism of the particular machine in question. The expected increase in the use of color copiers will pose a future challenge for forensic scientists. Diagrams, illustrations, and six references are supplied.
Index Term(s): Counterfeiting; Document analysis; Forgery; Office equipment
Note: This paper was presented at the Forensic Science Society's Spring Symposium, held at the University of Notingham (England), April 17-19, 1980.
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