Determining Line-Crossing Sequences Between Laser Printing and Writing Pen Using Coaxial Light

Determining the application sequence of hand-written pen ink and printer toner lines has attracted significant interest in questioned document examination. This study uses coaxial light to determine line-crossing sequences, with intersections observed under a VSC600 forensic document workstation and a Leica M205A Stereo-microscope. Results show that reflected light at intersections and color contrast between intersections and nonintersections was observed when a hand-written ink line passes over a toner line, while a toner line passing over a written line appeared dull, with no color contrast. The procedure was tested under a range of conditions, such as types of writing pens and laser printers, the writer, and writing pressure, with the latter playing an important role in the evaluation. To validate the results, a 90% detection rate and 98% accuracy rate were achieved from 50 samples of blind testing, which is more effective than optical microscopy.     

“万能制造机”背后的冷思考--3D打印技术安全风险及法律规制研究

3D打印作为一种快速成型技术,近年来发展迅速,有着良好的发展前景与应用空间。然而技术革新的背后潜在隐藏着知识产权、刑事犯罪以及人类伦理等多方面的安全风险,利用法律、政策规制3D打印技术迅猛发展可能带来的安全风险,既是保障社会治安管理秩序的关键,更是3D打印技术进一步发展与革新的前提与基础。     

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.     

A Preliminary Investigation into the Accuracy of 3D Modeling and 3D Printing in Forensic Anthropology Evidence Reconstruction,

There is currently no published empirical evidence‐base demonstrating 3D printing to be an accurate and reliable tool in forensic anthropology, despite 3D printed replicas being exhibited as demonstrative evidence in court. In this study, human bones (n = 3) scanned using computed tomography were reconstructed as virtual 3D models (n = 6), and 3D printed using six commercially available printers, with osteometric data recorded at each stage. Virtual models and 3D prints were on average accurate to the source bones, with mean differences from ?0.4 to 1.2 mm (?0.4% to 12.0%). Interobserver differences ranged from ?5.1 to 0.7 mm (?5.3% to 0.7%). Reconstruction and modeling parameters influenced accuracy, and prints produced using selective laser sintering (SLS) were most consistently accurate. This preliminary investigation into virtual modeling and 3D printer capability provides a novel insight into the accuracy of 3D printing osteological samples and begins to establish an evidence‐base for validating 3D printed bones as demonstrative evidence.     

3D打印治安管理对策研究

3D打印技术如今已受到了社会各界广泛的关注,有着良好的发展前景。然而其本身也具有着一定的治安隐患,如危险物品泛滥、特殊物品复制等。对于3D打印技术,需要进行系统的风险评估,并通过完善机制的构建进行人为控制,以保证其健康发展。这一机制的构建,除了应运用较多的高科技手段外,也应当在管理规范层面做到有序、协调。     

X射线荧光光谱法检验打印纸张的结果分析

目的对不同品牌的打印纸进行区分和鉴别。方法对21种不同品牌的打印纸进行X射线荧光光谱法（XRF）和X射线衍射法（XRD）检验，利用相关分析和聚类分析法对21种打印纸进行分类。结论XRF、XRD分析和数据分析相结合对纸张具有较好的区分能力。     

利用亚铁氰化钾与三价铁盐溶液反应进行足迹捺印

目的利用亚铁氰化钾与三价铁盐溶液反应生成普鲁士蓝沉淀的显色原理，探索非油墨捺印足迹的新方法。方法用脚沾取一定浓度的三价铁盐溶液，踩在经过亚铁氰化钾溶液处理过的纸张上。结果在经过处理的纸张上出现蓝黑色的足迹印痕。结论该方法安全卫生，操作简便，捺印效果好，具有一定的推广性。     

DVI-300微痕迹色差分析系统对激光打印文字与印章印文交叉时序检验的方法研究

目的研究常见的打印字迹与不同印章印文交叉时序的相关性,为检验提供依据。方法应用DVI-300微痕迹色差分析系统对制成的实验样本进行实体观察,并对微痕迹色差模型图进行特征分析。结果先墨后朱,交叉部位字迹边缘状态完整,等高线宽度、流向未见明显变化;先朱后墨,交叉部位中心字迹等高线排列出现游离状态,色料分布发生数字图形曲面变化。结论用本系统可以观察、分析朱墨交叉部位的微观特征和无损检验研究。     

颅骨三维模型制作和数据库的构建

目的采用激光扫描深度图像法和CT影像法,制作颅骨模型,并建立无身源颅骨模型数据库。方法收集各省(区)送检的59例无身源颅骨样本,采用三维激光扫描仪进行颅骨深度图像的采集;采用多排螺旋CT进行颅骨断层影像数据的采集。分别经处理后建立颅骨三维模型。利用3D打印技术实现数字颅骨模型的实体复制。建立具有颅骨信息查询和三维模型显示的无身源颅骨模型数据库。结果采用深度图像法可以获得颅骨的外表面模型,且通过调整扫描仪的参数使细节特征更清晰。采用CT断层影像法可以重建颅骨的内、外部结构,且对于牙齿具有更好的重建结果。建立数据库并将59例无身源颅骨样本信息和三维模型纳入数据库。结论三维建模和3D打印技术可实现对颅骨的重建和模型复制。无身源颅骨数据库的构建,可实现存储和管理颅骨样本的各类信息和三维数据,有助于查询和信息共享,对法医学实践有积极的应用价值。     

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。