Analysis of Pigmented Inkjet Printer Inks and Printed Documents by Laser Desorption/Mass Spectrometry*,†

Abstract: Anyone with a computer, scanner, and color printer has the capability for creating documents such as identification cards, passports, and counterfeit currency. Laser desorption mass spectrometry (LDMS) has been demonstrated as a powerful tool for colorant analysis. Inkjet printers are now moving largely toward the use of pigments as colorants; their insolubility makes analysis by simpler methods such as thin‐layer chromatography no longer an option. Recent developments in pigmented inkjet printer inks, such as gloss optimizers that coat pigment particles, may prohibit colorant analysis by LDMS. We demonstrate here that pigments used in inks from two Epson printers can be detected and analyzed by LDMS. Also, LDMS spectra of various colors created using a 4‐cartridge (cyan/magenta/yellow/black, CMYK) inkset are evaluated, to begin to develop an approach for unraveling LDMS data from real samples, to determine the number of inks used by a printer, and the chemical composition of the colorants.     

激光刻蚀等离子质谱测定打印纸中的常量和微量元素

目的研究激光刻蚀等离子体质谱法对打印纸品牌的区分能力。方法收集了国内20个不同品牌的打印纸,应用激光剥蚀等离子体质谱方法进行元素分析,并采用SPSS系统聚类方法对测试数据进行处理。结果依据元素响应值比值的差异将20个不同品牌的打印纸区分为12类。结论此方法可对打印纸品牌进行有效区分。     

利用暗记特征对HP系列彩色激光打印文件鉴别的研究

对激光打印文件的鉴别,尤其是彩色激光打印文件的鉴别,历来是可疑文件检验领域的难点和重点。利用暗记特征则为此类文件的鉴别提供了一种有效方法,即采用光学检验方法,对激光彩色打印文件暗记进行显现,利用暗记点阵形态特征和点阵排列含义特征等,为彩色激光打印机具的种类鉴别和个体鉴别提供了有效的鉴别依据。     

栅格特征在打印文件检验中的应用研究

目的通过对打印文字栅格特征进行实验研究,总结其稳定性和易引起特征变化的因素,为二次添加打印和换页变造文件检验探索新的思路。方法以500个常用汉字为主要研究对象,选用不同品牌、不同型号激光打印机,设置不同分辨率或质量模式,用同一台电脑或不同台电脑安装不同驱动程序,打印中易宋体常用字不同字号的样本。通过对打印文字笔画细节特征进行比对分析,总结打印文字栅格特征的规律特点。结果打印文字存在三类栅格特征,一是横笔段厚度特征,二是竖笔段宽度特征,三是斜笔画阶梯特征。同一台打印机一次打印的文件,相同字体字号文字的栅格特征反映相同;不同打印机或同一台打印机连接不同版本操作系统的电脑,或安装不同驱动程序,或选择不同的打印分辨率,栅格特征可能发生变化。结论栅格特征在同一次打印的文件中具有稳定性,在不同硬件和软件环境下可能发生改变,可以为换页文件和二次添加打印文件检验提供新的思路。     

利用ImageXpress系统灰度特征区分激光打印复印一体机的打印及复印文件初探

目的探索区分激光打印复印一体机的打印文件及复印文件的方法。方法利用ImageXpress系统对理光MP4000BSP激光打印复印一体机的打印文件和复印文件进行灰度特征值的测量。结果两种文件的灰度平均值的平均值和95%置信区间存有明显的差异,且这种差异较为稳定：打印件的平均值约为50,而复印件约为53;打印件的95%置信区间介于50和51.5之间,而复印件的置信区间介于52.5与54之间。结论本方法通过量化对激光打印复印一体机打印及复印文件进行区分是可行的。     

China and Central Asia: Bright Prospects for Economic Cooperation

正IN 138 BC,the royal court of the Western Han Dynasty sent Zhang Qian on a mission to the Western Regions,thus assigning the ancient Silk Road for trade and business exchanges between China and Central Asia,West Asia,as well as Europe and Africa.Since that time,this route saw China’s papermaking technology,compass,gunpowder,printing techniques,silk,tea and porcelain spread to the world,while spices and gems came into China.Central Asian countries,which the     

丝网版印章印文特征辨析

介绍了丝网版印章的制作工艺,分析了丝网版印章印文特征的可变性和稳定性,总结了丝网版印章印文检验的方法,为司法鉴定实践中此类印章印文的真伪鉴别工作提供一定参考。     

测量笔画增宽度判断激光打印文件朱墨时序初探

目的考察印章印文与激光打印字迹交叉部位的笔画增宽现象,得到朱墨时序判断依据。方法制作两种朱墨时序的实验样本,在VSC-6000文检仪下观察,读数显微镜在相同放大倍率测量,记录增宽度,比较同种品牌印文色料在两种时序下笔画的增宽度。结果相同保存条件下同种品牌印文色料不同时序盖印的实验样本都有增宽现象,先墨后朱时序下增宽度较大。结论该方法可以作为朱墨时序判断依据。     

An Overview of 3D Printing in Forensic Science: The Tangible Third-Dimension

There has been a rapid development and utilization of three-dimensional (3D) printing technologies in engineering, health care, and dentistry. Like many technologies in overlapping disciplines, these techniques have proved to be useful and hence incorporated into the forensic sciences. Therefore, this paper describes how the potential of using 3D printing is being recognized within the various sub-disciplines of forensic science and suggests areas for future applications. For instance, the application can create a permanent record of an object or scene that can be used as demonstrative evidence, preserving the integrity of the actual object or scene. Likewise, 3D printing can help with the visualization of evidential spatial relationships within a scene and increase the understanding of complex terminology within a courtroom. However, while the application of 3D printing to forensic science is beneficial, currently there is limited research demonstrated in the literature and a lack of reporting skewing the visibility of the applications. Therefore, this article highlights the need to create good practice for 3D printing across the forensic science process, the need to develop accurate and admissible 3D printed models while exploring the techniques, accuracy and bias within the courtroom, and calls for the alignment of future research and agendas perhaps in the form of a specialist working group.     

Characterization of Printing Inks Using DART‐Q‐TOF‐MS and Attenuated Total Reflectance (ATR) FTIR

The rise in improved and widely accessible printing technology has resulted in an interest to develop rapid and minimally destructive chemical analytical techniques that can characterize printing inks for forensic document analysis. Chemical characterization of printing inks allows for both discrimination of inks originating from different sources and the association of inks originating from the same source. Direct analysis in real‐time mass spectrometry (DART‐MS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) were used in tandem to analyze four different classes of printing inks: inkjets, toners, offset, and intaglio. A total of 319 samples or ~ 80 samples from each class were analyzed directly on a paper substrate using the two methods. DART‐MS was found to characterize the semi‐volatile polymeric vehicle components, while ATR‐FTIR provided chemical information associated with the bulk components of these inks. Complimentary data results in improved discrimination when both techniques are used in succession resulting in >96% discrimination for all toners, 95% for all inkjets, >92% for all offset, and >54% for all intaglio inks.