Analysis and Evaluation of Magnetism of Black Toners on Documents Printed by Electrophotographic Systems

Abstract

This paper reports on a study to assess the potential of measurements of magnetism, using a proprietary magnetic analysis system, for the routine analysis of toners on documents printed by black and white electrophotographic systems. Magnetic properties of black toners on documents printed by a number of different devices were measured and compared. Our results indicate that the analysis of magnetism is complementary to traditional methods for analysing black toners, such as FTIR. Further, we find that the analysis of magnetism is realistically applicable in closed set cases, that is when the number of potential printing devices can be clearly defined.

La position de la Section des documents de la SCSJ sur l'approche logique de l'évaluation de la preuve et le libellé des conclusions

“…Plusieurs articles sont apparus dans la litt erature sur l'approche logique, g en eralement en termes de rapport de vraisemblance ou de m ethode bay esienne. Dans le domaine de la science judiciaire, une grande partie de la discussion a eu lieu dans les journaux Science & Justice , Journal of Forensic Science Society [33][34][35], Journal of Forensic Sciences [36][37][38][39][40], et Forensic Science International [41][42][43][44][45][46][47][48][49]. Des discussions importantes apparaissent egalement dans le journal Law, Probability and Risk [50][51][52][53][54][55].…”

The assessment of the impact of induction spatial effects on magnetic flux measurements of toner‐printed documents to the detection of forged or altered documents

“…The conclusion was that magnetic flux measurements did provide the potential to discriminate samples from different origins, but further research was necessary to determine what variables may impact the measured values. An expanded study investigated the repeatability and reproducibility of measurements, inter‐operator variability, and the complementarities of results with other traditionally employed techniques (i.e., FTIR spectroscopy) on a sample set of 61 samples from 61 different devices [33]. They found that magnetic flux measurements were repeatable and improved the discrimination of documents printed using the same printer model and type of toner resin; they also highlighted the complementarities between magnetism and FTIR spectroscopy, In that same study, the authors also recommended that all measurements for a single case be conducted by the same operator to prevent misinterpretations of results due to the risks of inter‐operator variability.…”