A method for judging the writing time of carbon black gel pen handwriting
The carbon black neutral pen handwriting is detected through laser confocal Raman spectroscopy technology, and the writing time is judged using the aging curve, which solves the problems of sample damage and cumbersome detection steps in the existing technology, and achieves a fast and simple judgment of writing time, which has important application value for judicial appraisal.
Patent Information
- Application Number
- CN202411985025.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-08
AI Technical Summary
When judging the writing time of carbon black neutral pen, the prior art will cause irreversible damage to the sample, and the detection steps are cumbersome, making it difficult to meet the needs of judicial appraisal.
The ink of carbon black neutral pen writing was detected by laser confocal Raman spectroscopy, and the aging parameters were obtained through peak fitting and integral calculation, and the aging curve was drawn to judge the writing time. This method does not cause damage to the sample and is simple to follow.
It realizes the writing time of carbon black neutral pen writing quickly and simply, avoids sample damage, and simplifies the detection steps, which is conducive to the smooth development of judicial appraisal.
Smart Images
Figure CN119780061A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of writing sequence identification, and in particular to a method for judging the writing time of carbon black gel pen handwriting. Background Art
[0002] For a long time, the identification of handwriting writing time has been a hot topic in the document inspection community. However, due to the diversity of writing materials and writing tools, the complexity of influencing factors and the lack of basic research data, this problem has not been fundamentally solved for a long time. In recent years, gel-ink pens have become widely used writing tools in today's society, especially carbon black gel-ink pens. Since their colorants are mainly carbon black, which is more stable than black dyes, they are used in the signing of many important documents. In judicial appraisal practice, the demand for the identification of the formation time of carbon black gel-ink pen handwriting is increasing. Therefore, the research on its writing time has also received widespread attention from scientific researchers.
[0003] The main basis for judging the writing time is the change of the ink composition of the handwriting over time. At present, the main method used is chromatography to study the writing time of the gel pen. The gel pen ink is composed of colorants, solvents, resins and other additives. The colorant of carbon black gel pen ink is carbon black pigment, which has good chemical stability, lasting color, no obvious change over time, and poor solubility. It is difficult to extract with organic solvents and water. Therefore, carbon black colorant is not suitable for chromatographic analysis. The solvent components in gel pen ink are mainly polyols, such as ethylene glycol, propylene glycol, glycerol, diethylene glycol, triethylene glycol, etc. After the handwriting is formed, the solvent begins to evaporate, and the content gradually decreases over time. Therefore, the current chromatographic technology is based on these volatile solvents as the research object. Specifically, the content of volatile components in the ink with different writing time is extracted and measured, and the aging parameters are constructed based on this content. The aging curve of the aging parameters changing with time is drawn, so as to use the aging curve to judge the writing time of unknown samples. This method can judge the handwriting ink written within half a year. However, there are also some limitations. First, it will cause irreversible damage to the sample, which is not conducive to the subsequent work in forensic identification. Second, in the process of quantitative detection, chromatographic technology often needs to add other internal standards, and the components are relatively large, which makes the detection steps more cumbersome.
[0004] In view of the above problems, it is urgently necessary for technical personnel in this field to propose a method for determining the writing time of carbon black neutral pen handwriting without causing damage to the sample and with simple detection steps. Summary of the invention
[0005] In view of the above technical problems, the present invention provides a method for determining the writing time of carbon black neutral pen handwriting, which solves the problems of damage to samples and complicated detection steps in the prior art.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for judging the writing time of carbon black gel pen handwriting of the present invention specifically comprises the following steps: S1: Prepare samples. Prepare two groups of carbon black gel pen handwritings with known writing time, with at least 7 copies in each group; S2: Using laser confocal Raman spectrometer to detect the ink of carbon black gel pen writing to obtain Raman spectrum; S3: Use software to perform peak fitting on the Raman spectrum data, and integrate the target peak in the Raman spectrum to obtain the integral area; S4: Draw an aging curve using the ratio of the peak areas near the target peak as the aging parameter; S5: performing operations on the sample to be measured according to steps S2 and S3, and calculating the ratio of the peak areas near the target peak; S6: Determine the time range of the writing using the aging curve.
[0007] Furthermore, the writing times of the carbon black gel pen handwritings with known writing times in step S1 are 1106 days, 171 days, 141 days, 108 days, 77 days, 47 days and 14 days respectively.
[0008] Furthermore, the model of the laser confocal Raman spectrometer in step S2 is Japanese Horiba LabRAM HREvolution, with a test wavelength of 365 nm, a laser spot diameter of 2 μm, a power of 1.5 mW, and an integration time of 30 s.
[0009] Furthermore, the fitting software in step S3 is Origin2018.
[0010] Furthermore, the target peaks in the Raman spectrum in step S3 are 1100 cm -1 、1350cm -1 、1580cm -1 The peak area of nearby peaks.
[0011] Furthermore, the two groups of carbon black gel pen handwriting with known writing time are respectively the handwriting of M&G AGPK3705 and Deli S76 carbon black gel pen.
[0012] Furthermore, after the aging curve is drawn in step S4, a database on the writing time of the carbon black gel pen is established according to the aging curve.
[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention detects the handwriting of carbon black signature pens with different writing times by using Raman spectroscopy technology, finds the Raman spectral peak with stable position and height changing with time by observing the Raman spectrum, draws an aging curve with the ratio of peak areas as an aging parameter, and can quickly and easily judge the writing time of the sample to be tested through the aging curve. The judgment method of the present invention has simple steps and will not cause damage to the sample to be tested, which is conducive to the smooth development of subsequent judicial identification work. At the same time, the present invention provides a new and effective method for identifying the writing time of carbon black neutral pen, which has important application value for judicial identification. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Attached Figure 1 This is the Raman spectrum of the writing of Deli S76 carbon black gel pen in this embodiment; Attached Figure 2 This is the Raman spectrum of the writing of the Chenguang AGPK3705 carbon black neutral pen in this embodiment; Attached Figure 3 This is a fitting result diagram of the Raman spectrum data of the writing of Deli S76 carbon black gel pen for 14 days in this embodiment; Attached Figure 4 This is a diagram showing the fitting results of the Raman spectrum data of the writing of Deli S76 carbon black gel pen for 108 days in this embodiment; Attached Figure 5 This is a diagram showing the fitting results of the Raman spectrum data of the writing of Deli S76 carbon black gel pen for 171 days in this embodiment; Attached Figure 6 This is a diagram showing the fitting results of the Raman spectrum data of the writing of Deli S76 carbon black gel pen 1106 days in this embodiment; Figure 7 This is a graph showing the aging curves of the Deli S76 carbon black gel pen writing at different writing times in this embodiment; Figure 8 This is a fitting result diagram of the Raman spectrum data of the 47-day writing of the Chenguang AGPK3705 carbon black gel pen in this embodiment; Fig. 9 This is a fitting result diagram of the Raman spectrum data of the 77-day writing of the Chenguang AGPK3705 carbon black gel pen in this embodiment; Fig.10 This is a graph showing the fitting results of the Raman spectrum data of the 108-day handwriting of the Chenguang AGPK3705 carbon black gel pen in this embodiment; Fig.11 This is a fitting result diagram of the Raman spectrum data of the 141-day writing of the Morning Glory AGPK3705 carbon black gel pen in this embodiment; Fig.12 This is a fitting result diagram of the Raman spectrum data of the 171-day handwriting of the Chenguang AGPK3705 carbon black gel pen in this embodiment; Fig.13This is a graph showing the fitting results of the Raman spectrum data of the 1106-day handwriting of the Morning Glory AGPK3705 carbon black gel pen in this embodiment; Fig.14 This is a fitted aging curve diagram of the handwriting of the Chenguang AGPK3705 carbon black neutral pen at different writing times in this embodiment. DETAILED DESCRIPTION
[0015] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0016] Example 1
[0017] A method for determining the writing time of carbon black gel pen handwriting in this embodiment specifically comprises the following steps: S1: Prepare samples. Select two groups of 7 samples written with M&G AGPK3705 and Deli S76 carbon black gel pens. The writing time is 1106 days, 171 days, 141 days, 108 days, 77 days, 47 days and 14 days respectively. S2: The Raman spectrum of the carbon black gel pen ink was obtained by using the Horiba LabRAM HR Evolution laser confocal Raman spectrometer from Japan, where the test wavelength was 365nm, the laser spot diameter was 2μm, the power was 1.5mW, and the integration time was 30s; S3: Use Origin2018 software to perform peak fitting on the Raman spectrum data in step S2, and fit the target peak 1100cm in the Raman spectrum. -1 、1350cm -1 、1580cm -1 The peak areas of nearby peaks were integrated to obtain the integrated area; S4: Target peak 1100cm -1 、1580cm -1 The ratio of the nearby peak areas is used as an aging parameter to draw an aging curve; a database on the writing time of the carbon black neutral pen is established based on the aging curve; S5: performing operations on the sample to be measured according to steps S2 and S3, and calculating the ratio of the peak areas near the target peak; S6: Determine the time range of the writing using the aging curve.
[0018] See attached Figure 1-14 , attached Figure 1-2 The Raman spectra of two carbon black gel pen inks are at 1100 cm -1 、1350.00cm -1 、1580cm -1There is an obvious peak at each position in the range, and 1100cm -1 The peak shows a trend of decreasing with time. Figure 1-2 As a result, the peak positions of these three ranges were mainly fixed during data fitting. Since the composition of signature pen ink is very complex and there is currently no Raman spectrum library of the various components of signature pens, it is difficult to indicate which substance each peak corresponds to. When fitting the data, we focus on the carbon D band, G band, and 1100 cm -1 Nearby peaks. Figure 4-6 The fitting results of the Raman spectra of Deli S76 carbon black gel pen at different writing times. Among them, peak fitting 1, peak fitting 2, and peak fitting 3 correspond to 1100 cm -1 Nearby, 1350 cm -1 Nearby, 1585 cm -1 It can be seen from the figure that the peak near 1350 cm -1 Nearby, 1585 cm -1 The intensity and size of the peaks near 1100 cm -1 The size and intensity of the peaks near 1100 cm -1 The peak area near 1585 cm -1 The ratio of the peak areas near the aging parameters was used to plot the changing trend of the ratio with writing time, as shown in the attached figure. Figure 7 As shown in Figure 2, the peak area ratio decreased from 0.18 on day 14 to 6.4 × 10 on day 1106. -6 , and it decreases quickly in the early stage and slowly in the later stage.
[0019] Attached Figure 8-13 This is the fitting result of the Raman spectra of the Chenguang AGPK3705 carbon black gel pen at different writing times, which is similar to the result of Deli S76. Among them, peak fitting 1, peak fitting 2, and peak fitting 3 correspond to 1100 cm -1 Nearby, 1350 cm -1 Nearby, 1585 cm -1 It can be seen from the figure that the peak near 1350 cm -1 Nearby, 1585 cm -1 The intensity and size of the peaks near 1100 cm -1 The size and intensity of the peaks near 1100 cm -1 The peak area near 1585 cm -1 The ratio of the peak areas near the aging parameters was used to plot the changing trend of the ratio with writing time, as shown in the attached figure. Fig.14As shown, the peak area ratio decreased from 0.66 on day 47 to 0.18 on day 1106, and decreased rapidly in the early stage and slowly in the later stage. The changing trend was the same as that of Deli S76.
[0020] In other embodiments, more than 7 samples may be selected in step S1. The number of samples prepared includes collecting more brands and models of carbon black gel pens, making handwriting samples with more writing time ranges, fitting an aging curve based on a large sample size, and using the aging curve in combination with the chemometric method to determine the writing time of the detection, so as to perform more accurate fitting and data processing of the Raman spectrum data. The increase in the sample size can further standardize the fitting process to reduce random errors and improve the reliability of the method.
[0021] Example 2
[0022] Select the sample to be tested with known time, and perform the operation according to steps S5 and S6 in Example 1. The results are shown in the table below.
[0023]
[0024]
[0025] It can be seen from the above measurement results that the time range of the handwriting determined by the aging curve is basically the same as the time range of the known handwriting, and the percentage error does not exceed ±3%. It can be seen that the method of judging the writing time of carbon black neutral pen handwriting in this embodiment is not only accurate, but also has simple detection steps and will not cause damage to the sample to be tested, which is conducive to the smooth development of subsequent forensic identification work and has important application value for forensic identification.
[0026] Beneficial effects of this embodiment: This embodiment detects the handwriting of carbon black signature pens with different writing times by using Raman spectroscopy technology, finds the Raman spectral peak with stable position and height changing with time by observing the Raman spectrum, draws an aging curve with the ratio of peak areas as the aging parameter, and can quickly and easily determine the writing time of the sample to be tested through the aging curve. The judgment method of this embodiment has simple steps and will not cause damage to the sample to be tested, which is conducive to the smooth development of subsequent judicial identification work. At the same time, this embodiment provides a new and effective method to identify the writing time of carbon black neutral pen, which has important application value for judicial identification.
[0027] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for determining the writing time of carbon black gel pen handwriting, characterized in that: The specific steps include: S1: Prepare samples. Prepare two groups of carbon black gel pen handwritings with known writing time, with at least 7 copies in each group; S2: Using laser confocal Raman spectrometer to detect the ink of carbon black gel pen writing to obtain Raman spectrum; S3: Use software to perform peak fitting on the Raman spectrum data, and integrate the target peak in the Raman spectrum to obtain the integral area; S4: Draw an aging curve using the ratio of the peak areas near the target peak as the aging parameter; S5: performing operations on the sample to be measured according to steps S2 and S3, and calculating the ratio of the peak areas near the target peak; S6: Determine the time range of the writing using the aging curve.
2. A method for determining the writing time of carbon black gel pen handwriting according to claim 1, characterized in that: The writing times of the carbon black gel pen writings with known writing times in step S1 are 1106 days, 171 days, 141 days, 108 days, 77 days, 47 days and 14 days respectively.
3. A method for determining the writing time of carbon black gel pen handwriting according to claim 1, characterized in that: The model of the laser confocal Raman spectrometer in step S2 is Japanese Horiba LabRAM HR Evolution, with a test wavelength of 365 nm, a laser spot diameter of 2 μm, a power of 1.5 mW, and an integration time of 30 s.
4. A method for determining the writing time of carbon black gel pen handwriting according to claim 1, characterized in that: The fitting software in step S3 is Origin2018.
5. A method for determining the writing time of carbon black gel pen handwriting according to claim 1, characterized in that: The target peaks in the Raman spectrum in step S3 are 1100 cm -1 、1580cm -1 The peak area of nearby peaks.
6. A method for determining the writing time of carbon black gel pen handwriting according to claim 1, characterized in that: After the aging curve is drawn in step S4, a database on the writing time of the carbon black gel pen is established according to the aging curve.