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Research On The Characteristics Of The Common Printing And Copying Files Of MFPs And Digital Copiers

Posted on:2016-01-31Degree:MasterType:Thesis
Country:ChinaCandidate:C J MaFull Text:PDF
GTID:2296330479988127Subject:Forensic
Abstract/Summary:PDF Full Text Request
The production method of printed document has been one of the major problems in questioned document examination. However, to identify whether the document is printed or copyed also requires the research of the principle mechanism of document production. Since it is difficult to identify the production machine of a printed document, the theoretical study is highly specialized and some other reasons, there lacks studies directly on the above issues.Printing services market is currently booming. Purchasing multi-functional office equipment to replace the mutually isolated functions of old printers and copiers for the maximized profits and improvement of office automation has become a growing trend. Typical multi-functional office equipment, mainly MFP and digital copier, is equipment with the integrated functions of printing, copying, scaning and faxing. The successful development of MFPs and digital copiers are both opportunities and challenges to the study of printed document examination.This article is an important part of <Key technologies of non-destructive examination of printed document>, aiming at studying the main characteristics of documents produced by MFPs and digital copiers, and analyzing their similarities and differences. There are five steps in the research process: the first is to collect, analyze and summarize the relevant information. The existing literatures about the concepts, perspectives, experimental programs and corresponding results relevant to the study were reviewed. The second is a study of common MFP and digital copier brands and models, selecting the test samples.The operating principles and the inherent characteristics of various types of equipments were explored to design the for experimens and testing methods. The third is to collect and reorganize the printed samples of selected MFPs and digital copiers. The fourth is about the testing methods used in this research, including using the VSC6000 to observe the trace features of copy board, photosensitive drum and tracking code, etc.; using the stereo microscope to observe the morphological characteristics; using the Image Xpert system to measure the gray value and other related data of samples. The fifth is to summarize the results of the study.Based on a total number of 2444 pages of printed samples in 39 groups, the experiments were focused on a comprehensive examination of these samples. Firstly, using VSC6000 is able to observe the traces of photosensitive drum which are different between copied documents and printed ones, and there is difference in regulation between traces of photosensitive drum and traces of copy board. Meanwhile, a part of color printed documents produced by some machines have regular tracking codes. Secondly, using stereo microscope is able to observe the detail characteristics of samples. And the printing traces on are different on the printed document and the ones copied for once, twice and three times, which were all produced by the same equipment. Generally, the printing traces increase with the copy times, no matter the machine is the laser MFP, digital copier or inkjet MFP. Finally, using the Imagexpert system is able to test the regular change of gray value. It was found out that there is no certain high or low gray value between printing files and copying files. Moreover the average gray values ofdifferent thickness strokes or lines on the same area of the same page have notable features.After the series of testing process, the author believes that it is feasible to use morphological method in the printed document examination, especially on the basis of traces of copy board, which indicate a high credibility of copying. On the other hand, quantification method also have some breakthroughs, the phenomenon of convergence of gray values of different thickness strokes or lines on a copied file is worth further study.As a matter of fact, based on a single examination method to identify a printed file or a copied file is still inappropriate. In stead, a comprehensive analysis of different examination results may provide some technical support for the investigation and identification.
Keywords/Search Tags:Printed document, Trace characteristics, Microscopic characteristics, Average gray value
PDF Full Text Request
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