Influence of Software on the Features of Laser-printed Characters

Abstract

Verifying the authenticity or otherwise of printed documents is one of the most important aspects of questioned document examination and plays a vital role in the field of forensic science. In recent years, continued developments in the quality of impression combined with ever-cheaper toner printers have allowed this technology to spread. It is now used in an increasing number of homes for all types of documents, including for criminal aims. Here, the factors that influence the printed features in text files are studied in relation to the operating system and the word processing software. The Net Application report in October 2014 showed that the market shares of Windows 7 and Windows XP were 53.05% and 17.18%, respectively. The Forrester report in October 2013 showed that the market share of Microsoft Office was more than 85%, the top three word processors being Microsoft Word 2003, 2007, and 2010. In this study, Windows XP (shortened to XP), Windows 7 (shortened to Win7), Microsoft Word 2003/2007/2010, WPS Office 2013, and the PDF format are chosen as the most common operating systems and word processing software. WPS Office was developed by the Chinese company Kingsoft Co., Ltd. and is widely used in China. A particular text file was designed and edited and was printed on a laser printer. The features of the printed characters were captured using an Anyty 3R digital microscope, Printer Expert, and X-printer devices. Coincidence comparison and outline feature extraction were used to evaluate the differences. It is shown that XP and Win7 have no effect on the printed features of text files. However, the printed features do depend to a certain extent on the word-processing software, with the PDF format having the greatest influence.