线聚焦显微激光拉曼光谱技术区分激光打印墨粉

目的利用Renishaw InVia激光显微拉曼光谱仪对打印墨粉进行区分。方法用785nm激发波长,采取线聚焦模式,50倍物镜条件下,测定了惠普等8个品牌25种硒鼓型号的30份激光打印机打印墨迹样品的拉曼光谱。结果 30种样品墨迹的谱图进行了分析,根据拉曼的异同,可将30种样品分为5大类。结论线聚焦显微激光拉曼光谱可用于区分不同种类激光打印墨粉。     

红外光谱结合化学计量学方法在激光打印原装黑色墨粉分析中的应用研究

目的 采用红外光谱比较分析不同原装黑色墨粉（31个样本）的差异,探讨化学计量学方法在墨粉种类识别中的适用性.方法 对打印样本纸张上的黑色墨粉进行烫熨提取后直接分析检测.IR分析条件：显微红外光谱仪,常温透射模式,扫描范围为4 000～400 cm-1,分辨率为16cm-1,累计扫描次数为64次.结果 墨粉树脂主要为聚苯乙烯/甲基丙烯酸甲酯和聚对苯二甲酸/环氧树脂.采用主成分析（Principal Component Analysis,PCA）与系统聚类法（Hierarchical Cluster Analysis,HCA）对不同种类墨粉进行聚类分析与建模预报.基于前两主成分得分值（53.3％）不同树脂成分的墨粉样本聚类效果明显,同时在第三个主成分方向上黑白与彩色激光墨粉样本获得良好区分.结论 红外光谱法结合化学计量学方法用于不同种类树脂及打印类型原装黑色墨粉的聚类分析与建模预报方法可行,结果准确可靠.     

微束X射线荧光分析法鉴别激光打印机墨粉的研究

目的利用微束X射线荧光分析法（μ-XRF）研究激光打印机用墨粉的鉴别。方法利用μ-XRF对9台不同型号激光打印机用墨粉、对应的打印字迹、提取的字迹墨粉所含元素进行定性、半定量的分析。结果根据检出元素种类的不同,可将9台不同型号激光打印机用墨粉、对应的打印字迹、提取的字迹墨粉分成7类、4类、4类,区分率分别为94.4%、75%、69.4%。结论本研究所建立的μ-XRF鉴别激光打印机墨粉方法具有微区、原位无损检验等优点,对提高激光打印文件检验水平具有现实意义。     

显微激光拉曼光谱法鉴别黑色圆珠笔油墨的初步研究

利用显微激光拉曼光谱法对纸张上黑色圆珠笔油墨字迹进行检验,结果表明 ,对不同的黑色圆珠笔油墨可以有效鉴别。该方法快速、简便、不破坏样品。     

打印复印文件朱墨时序表观特征初探

本文详细介绍了一案例的检验过程,并通过简单实验对激光打印、静电复印形成文件的朱墨时序的表观特征进行了粗浅的探究。总体而言,两种时序在朱墨交叉点的表观特征上具有文字与印文均完整、肉眼感觉文字均压在印文之上的共同点;在两者本质的差异点上,先朱后墨表现为交叉点的墨粉与未交叉部位一致,先墨后朱表现为交叉点的墨粉光泽度增加、具有潮湿感、以及易出现水珠状的印油积聚现象。     

显微激光拉曼光谱技术区分喷墨打印墨迹研究

目的运用激光显微共聚焦拉曼光谱仪对打印墨水的墨迹样品进行检验。方法采用514nm激发波长,测得EPSON、HP、CANON等3个品牌21种型号墨迹样品的拉曼光谱。结果根据拉曼峰位的异同,可将21种型号墨迹样品分为8大类。结论该方法可以快速区分常见不同种类打印墨水墨迹,为印刷文件的检验鉴定提供方法参考。     

利用感光鼓损伤印迹确定激光打印件的相对形成时间

目前，司法鉴定中各种有争议的文件物证，往往存在被伪造的可能，其中更换合同中的打印件，在各类民事诉讼案件中出现频率较高，检验难度较大。如何利用无损检验方法揭示文件有无伪造及如何伪造，是鉴定人员面临的问题。本文介绍了利用感光鼓损伤印迹确定激光打印件相对形成时间的一种无损检验的方法。     

裂解气相色谱法检验静电复印墨粉

静电复印墨粉是复印文件检验的重要组成部分。本文通过电熨斗加热提取纸张上的墨粉,排除了纸张的平扰,用裂解气相色谱法对9个厂家共23个型号的墨粉进行检验。研究表明。该方法灵敏度高,分辨能力强,区分率可达到90.3％,是一种有效的检验方法。     

利用暗记特征鉴别彩色激光打印、复印文件

目的探讨激光打印机的暗记特征,为鉴别彩色激光打印、复印文件找到一种有效的方法。方法根据不同物质对光的反射特性及蓝色与黄色互补特性的原理,采用420nm左右蓝光照射方法,对部分品牌彩色激光打印、复印文件进行了初步分析研究,总结了暗记点阵形态特征、小点形态特征、出现位置特征和排列含义等特征。结果此方法对彩色激光打印、复印机具的种类鉴别和个体鉴别简便、有效。     

傅立叶变换红外光谱法检验静电复印墨粉

目的　通过对静电复印墨粉进行检验 ,达到对不同厂家及不同型号墨粉区分的目的。方法　首先利用电熨斗加热提取复印件的墨粉 ,然后利用傅立叶变换红外光谱法对 9个墨粉厂家和 2 4种牌号进行检验。结果可以达到厂家区分和大部分牌号区分 ,区分率达到 95 .7%。结论　本研究对实际应用有较大参考价值。     

化学显色法分析喷墨打印机黑色墨水的种类

目的建立化学显色法检验喷墨打印机字迹色痕的方法。方法选用不同的试剂或混合试剂,对22种不同品牌的喷墨打印黑色墨水的溶解性及与不同试剂的颜色反应进行观察。结果不同品牌的喷墨打印机黑色墨水的溶解性不同,与不同试剂作用会显现不同的颜色。结论化学显色法快速、简便,可用于现场的快速检验。     

An Examination of the Sequence of Intersecting Seal and Laser Printing Toner Line

Examining the sequence of intersecting seal and laser printing line is a significant method of determining the authenticity and validity of documents. In this study, five brands of stamp pad inks, three types of inkpads and seven kinds of laser printers were used to make heterogeneous line intersections. Observation method of physical characteristics, scraping technique and fluorescence method was used to determine the sequence of intersecting lines. Distinguishing features were noted between the materials produced in both sequences. As the results obtained from the study were positive, these features might provide a scientific basis for accurately determining the sequence between laser printing line and inkpad (stamp pad ink) seal.     

黑色墨迹的拉曼光谱分析

目的对常见的黑色墨迹进行初步筛选,为墨迹的进一步检验提供依据。方法依据黑色墨迹的同色异谱特征,利用显微共焦激光拉曼光谱仪对19种黑色墨迹进行分析检验。结果根据不同墨迹的拉曼谱图,19种黑色墨迹可以分为3大类,即:未检出拉曼峰的墨迹,只检出碳物质的墨迹,以及主体色料为染料的墨迹。结论拉曼光谱可用于区分不同种类黑色墨迹,从而为选择合适的方法对黑色墨迹进一步进行检验奠定基础。     

Determination of the Chronological Order of a Laser Printing and Gel Pen Writing Without any Crossing Strokes

Laser printers and writing instruments are being exploited by the forgers to produce fabricated documents. They often produce such documents by appending genuine signature on a blank sheet and later printing on it. Often these fabricated documents do not contain intersection of strokes and may pose a difficulty to forensic document examiners in analyzing cases related to such documents. Keeping in mind the limited research work done on nonintersecting strokes, the present study has been conducted with an aim to determine the sequence of nonintersecting strokes of gel pens and laser printers. Three hundred samples of nonintersecting strokes of gel pen ink and laser printing were prepared. Of these 300, 150 had laser-printed text below the gel pen strokes and the remaining 150 were prepared with gel pen stokes below the laser-printed text. The samples have been analyzed using Nikon SMZ 800N stereomicroscope. Three micro-conformation features, that is, pattern of toner distribution, ink distribution, and fiber distribution have been observed in the samples. The results demonstrate the successful establishment of sequence of nonintersecting strokes in case of gel pen and laser-printed documents by the determination of micro-conformation features.     

Application of Video Spectral Comparator (absorption spectra) for establishing the chronological order of intersecting printed strokes and writing pen strokes

The sequence of intersecting strokes of laser printers (black, blue, red and green) and typewriter ink (black) with the strokes of gel pen ink, ballpoint pen ink and fountain pen ink (black, blue, red and green) has been determined by studying their absorption spectra. The absorption spectra have been generated for each of the two pure inks (i.e. A and B) and points of their intersections (i.e. A over B and B over A) by using Video Spectral Comparator (VSC-2000-HR). The study was carried out with an assumption that the peak characteristics of spectra from the point of intersection should correspond to the peak characteristics of pure ink which was executed later. It was observed that the absorption spectrum of intersection corresponds with either the laser printer or the typewriter ink stroke, whether these strokes were executed earlier or later than the writing instrument strokes. As the results obtained from the study were negative, the FDEs are advised against the practice of this technique in the examination of the sequence of intersecting strokes for these specified inks.     

Examination of the Sequence between Laser Printing and Rollerball Pen Writing Without an Intersecting Stroke

Examining the sequences of printing and writing is a significant method of determining the authenticity and validity of documents. Forensic document examiners have extensively studied crossing lines, which has produced useful information. However, the sequence for laser printing and rollerball pen writing without crossing strokes has not been studied. To solve this problem, volunteers were invited to write characters on A4 paper with different rollerball pens using two sequences. Four laser printers applied print to these sheets, and the materials were examined using an Optem A-Zoom2 video tomography microscope. Consequently, distinguishing features were noted between the materials produced in both sequences. These features might provide a scientific basis for accurately determining the sequence between laser printing and rollerball pen writing in the absence of intersecting strokes.     

Application of Raman spectroscopy in forensic investigation of questioned documents involving stamp inks

Stamp pad inks from different manufacturers across India have been analyzed to investigate the feasibility of Raman scattering as a tool for forensic analysis of questioned documents involving stamp inks. Nine different stamping inks were analyzed by both Raman spectroscopic and HPTLC methods. The results demonstrate the effectiveness of these methods in classifying the investigated stamping inks based on their spectral pattern and HPTLC chromatogram. Raman scattering tool was able to determine the sequence of heterogeneous intersection strokes involving a blue stamp pad ink and other writing instruments, such as ballpoint pen ink (red and black), pencil and laser printer toner. However, this method was unable to resolve the exact sequencing for the intersection strokes involving investigated stamp ink and blue ballpoint ink or gel pen ink (all colors).     

The Capability of Raman Microspectroscopy to Differentiate Printing Inks

This study applies Raman microspectroscopy to differentiate the chemical components in printing inks of different brands, colors, and type using the 532 nm and 785 nm excitation wavelengths. Spectra were collected from 319 inks (78 inkjet, 76 toner, 79 offset, and 86 intaglio) representing various colors. Comparisons were performed to calculate discrimination capability percentages for each ink type. Overall, Raman microspectroscopy differentiates according to the following hierarchy: intaglio (96%), inkjet (92%), offset (90%), and toner (61%). The ability of Raman microspectroscopy to differentiate between same‐colored inks from different brands was dependent on the color and ink analyzed. Based on ink color, the discrimination capability ranged from 75 to 94% (inkjet), 0 to 86% (toner), and 0 to 77% (offset). Copper phthalocyanine was detected in cyan inks and various intaglio inks, while carbon black was identified in black inkjet, offset, and intaglio inks.     

TDS-GC/MS法检测黑色中性笔墨迹中挥发性溶剂的历时性变化

目的应用热脱附-气相色谱/质谱(TDS-GC/MS)分析,研究7支黑色中性笔墨迹中挥发性溶剂的历时性变化规律。方法选取7支不同品牌的黑色中性笔,分别在A4纸和笔记本上进行一次制样,然后在不同时间点取样,应用所建TDS-GC/MS方法分析墨迹中乙二醇、二甘醇和三甘醇在200余天内的含量变化。结果6支笔中的乙二醇、三甘醇的含量在2个月之内有明显的下降,另1支笔中二甘醇的含量在5个月内还能观察到较明显的下降。目标物的历时性变化趋势能拟合成幂函数或对数函数。不同的纸张、不同的墨水对检测结果均有影响。结论黑色中性笔墨迹中的挥发性溶剂的含量随时间增加而下降,应用所建TDS-GC/MS方法,能为判断需检墨迹是否处于溶剂含量明显变化的阶段提供依据。     

Visualization method for fingerprints on skin by impression on a polyethylene terephthalate (PET) semirigid sheet.

Based on the phenomenon that static electricity attracts dust, a polyethylene terephthalate (PET) semirigid sheet coated with printing ink was used to visualize impressions of fingerprints on the skin of living and dead bodies. Compared with visualization methods for perspiration fingerprints, this method recovers better images for a longer time after the fingerprint has been deposited on skin. Fingerprints transferred to the PET sheet are photographed with sidelighting using an ordinary light source. For fingerprints that yield inadequate contrast, an argon-ion laser can be used to improve the contrast.