KR101463461B1 - Monitoring method of printer inks on documents using tof sims and system for the same - Google Patents

Abstract

A method for monitoring ink on documents according to one embodiment of the present invention obtains the source information of the ink by comparing an equivalent condition by comparing normalized data with a preset spectrum database after a flight secondary ion mass analysis spectrum corresponding to an ink part on the documents is measured and a fingerprint spectrum is obtained. The equivalence and difference of the ink and the truth of the documents written without damaging a specimen are quickly and accurately determined by using the method for monitoring the ink on the documents.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of identifying ink on a document using a time-of-flight secondary ion mass spectrometry,

The present invention relates to a method for identifying the source and the identity of a document printing ink through mass analysis of compounds constituting an ink component of a printer included in a document in the authenticity test of forgery or falsification of the document.

Recently, the importance of identification technology for traces of crime is increasing. Various documents related to property, such as various insurance contracts, documents related to gifts or inheritance, and real estate contracts are increasing, and the necessity of feeling authenticity about the forgery and alteration of documents is also increasing.

Forgery of general counterfeit documents or documents was mainly based on handwriting by the appraisers who accumulated a lot of experience, but did not provide enough information to identify the homogeneity of the printing ink. In addition, the results of the test were subjective, and there were many aspects that were not objective by involving many unscientific factors. Therefore, it is important to judge whether or not falsification is based on the identification of the components of the printer ink used in such documents.

In comparing the authenticity of the document with the printer ink contained in the document, the authenticity of the agreement document can be quickly and accurately and objectively judged by checking whether the document is the same or not. In particular, it provides objective criteria for identifying the identity and authenticity of a document printing ink through the analysis of inks, dyes and pigments of printer ink used in documents such as contracts.

More scientific and objective empirical methods for counterfeiting of printing inks used in contracts, works of art, and documents have been proposed, including thin layer chromatography, high performance liquid chromatography, high performance thin layer chromatography high performance thin layer chromatography, and gas chromatography. However, since thin film chromatography or the like causes damage to samples (contracts, art works, documents, etc.) by solvent extraction, it becomes a problem when revalidation is required in the future, and in particular, There is a serious problem.

Optical microscopy is widely used as a non-destructive method to solve the problem of damaging the sample. However, there is much room for such analytical methods to be intervened by analysts and observers.

In a digitized modern society, almost all documents can be written by a computer. Especially, the font and size on the surface of the document are directly produced by the computer and it is difficult to judge whether the document is identical or not through the document. Therefore, there is a need for a method for evaluating the identity of a printed document by using a non-destructive inspection method.

It is an object of the present invention to provide a method for identifying the identity of a printing ink of a document in a non destructive manner. In order to determine whether the printer ink is the same or not in a document printed by a printer or the like, it is determined whether or not the contract document is falsified based on the time-of-flight secondary ion mass spectrometry (TOF-SIMS) It is a way to be able to do.

According to an aspect of the present invention, there is provided a method of detecting ink on a document, comprising: measuring a mass spectral spectrum of a paper portion and a character portion of a document sample; Obtaining an ink spectrum of the sample excluding the spectrum; Obtaining a fingerprint spectrum corresponding to a mass value of a peak characteristic of the ink from the ink spectrum; Calculating a value of the ion intensity of the fingerprint spectrum by dividing the relative ion intensity of the peak corresponding to the fingerprint spectrum by the total ion intensity of the spectrum of the ink; Retrieving data satisfying an equivalence condition with a search key of the ink including the fingerprint spectrum and the ion intensity value from the spectrum database for the printer ink; And outputting the information of the source of the ink which is searched from the database as satisfying the equivalence condition.

The mass spectrometry spectrum of the sample and the database means a spectrum measurement result obtained by a time-of-flight secondary ion mass spectrometry (TOF-SIMS) method.

In the step of obtaining the ink spectrum of the sample, a position to measure the spectrum of the character portion in the sample may be further selected before the spectrum of the character portion is measured.

The step of selecting the position of the character part may be a process of searching for the position of a character part to be subjected to spectrum measurement by using pattern matching or using a font of a character described in ink in a document.

In other words, the spectrum can be measured by selecting a portion where no ink is present even after printing in a document and a portion where a character or the like is printed by printing. In particular, the paper portion of two or more documents corresponding to each other through pattern matching, And the character part can be selected to measure the spectrum.

It is common to print two or more documents such as a contract, respectively, to paint or sign each, in which case the printing of these two or more documents can be printed using the same printer. Therefore, if the authenticity of two or more copies having the same contents is recognized, it can be a good data for judging authenticity of the document if it is possible to confirm whether or not printing of a pattern matching each other is printed on the same printer.

Therefore, it is preferable to select a measurement target of a spectrum in consideration of the pattern matching or character font matching at the time of selecting the print portion and the character portion to measure the spectrum in the document, and to improve the efficiency of the document evaluation have.

Measuring the mass spectrum of a document using the TOF-SIMS (Flying Type Secondary Ion Mass Spectrometry) instrument is a method in which secondary ions are generated from the surface of the document by the primary ions, The time for ions to reach the detector depends on the mass of the quadrature on. That is, the minimum of molecular fragmentation of molecules on the surface of a document can be used to analyze the identity of elements and compounds in the ink.

The primary ion used in the flying type secondary ion mass spectrometry may be selected from ion sources including Bi and Cs. The amount of irradiation of the sample with the primary ions may be 10 ¹³ ions / cm ² or less. When the irradiation amount of the primary ion is limited within such a range, the molecules constituting the surface of the document minimize the destruction and enable non-destructive document recognition.

The fingerprint spectrum of the sample may be that there is a peak within the mass value range of 0 to 400 m / z. Wherein the fingerprint spectrum has a mass value of less than or equal to 100 m / z, the fingerprint spectrum may be a mass value corresponding to inorganic elements included in the ink, the fingerprint spectrum has a mass value of greater than 100 m / z, May be a mass value corresponding to an organic compound, a resin or an organic additive contained in the ink.

The step of obtaining the ion intensity value is a reference process for dividing the relative ion intensity of the peak corresponding to the fingerprint spectrum by the total ion intensity of the ink spectrum. For example, the mass spectrum may be modified to change the mass spectrum of the bar graph Or the like.

The method of detecting ink on the document may further include classifying the ion intensity value between the step of obtaining the ion intensity value and the step of retrieving the data.

The step of classifying the ion intensity values may include classifying the fingerprint spectrums by giving preference to a larger ion intensity value of the fingerprint spectrum, and the step of retrieving the data may include: And to retrieve data for the printer ink that satisfies the equivalence condition with the database. When searching in this order, it is possible to improve the efficiency of identification.

The equivalence condition may be that the equivalence value between the search key of the ink and the data of the corresponding database is 70 or more. The step of outputting the information may output the information of the equivalence condition value while outputting the source information of the ink that satisfies the equivalence condition.

In addition, the step of outputting the information may further output information such as ion intensity of a mass value corresponding to a volatile organic compound. From this information, it is also possible to obtain information relative to the output time of the document.

According to another embodiment of the present invention, there is provided a system for detecting ink on a document, comprising: an irradiating unit for irradiating primary ions of a paper portion and a character portion of a sample, which is a document; A measuring unit for measuring a flying type secondary ion mass spectrometry spectrum by accelerating and detecting the binary difference formed by the primary ions; A first arithmetic unit for obtaining a spectrum of the ink using the letter partial spectrum and the paper partial spectrum of the sample measured by the measurement unit; A second arithmetic unit for obtaining a fingerprint spectrum corresponding to a mass value of the peak from the spectrum of the ink; A third order arithmetic unit for obtaining an ion intensity value of the fingerprint spectrum through a standardization process of dividing the relative ion intensity of the peak corresponding to the fingerprint spectrum of the ink by the total ion intensity of the ink spectrum; A search unit for comparing the fingerprint spectrum and its ion intensity value with values corresponding to a search key of a spectral database for a printer ink to search for whether the equivalence condition is satisfied; And a display unit for outputting the information of the source of the ink derived from the search unit.

The fingerprint spectrum of the sample may be in a mass value range of 0 to 400 m / z, and the fingerprint spectrum has a mass value of 100 m / z or less, and the fingerprint spectrum corresponds to inorganic elements contained in the ink Mass value, the fingerprint spectrum has a mass value of greater than 100 m / z, and the fingerprint spectrum may be a mass value corresponding to an organic compound, a resin, or an organic additive contained in the ink.

The primary ion used in the flying type secondary ion mass spectrometry may be selected from ion sources including Bi and Cs.

Using the method and system for detecting ink on the document, it is possible to know the identity and origin of the ink used in the document in a non-destructive manner, and can be used for authenticity and analysis of authenticity. The method and system for detecting ink on the document can analyze the components of the ink to discriminate the origin and the model name of the product of the printing ink and also obtain information on the identity of the preparation time or the like in accordance with the degree of volatilization of the volatile organic compound in the printing ink Can be confirmed. Therefore, it is possible to determine whether or not the document is falsified from the above information, so that it can be utilized for judging whether the document is falsified or not.

According to the method of detecting the inks on the document using the mass spectrometry as described above, the spectrum of the unknown printer ink used in the document printing is analyzed by using the high-performance resolution of the TOF-SIMS analysis equipment, It is possible to quickly and accurately judge identity, discrimination and authenticity of documents. The non-destructive method can be usefully used in the field of forensic science, archives, and the emotional field of artworks.

1 is a conceptual diagram for explaining a method of identifying a printer ink on a document according to an embodiment of the present invention.
FIG. 2 is a graph showing the relationship between the TOF-F values of inks measured from letters printed as samples of black printer inks (for ink jet printing) according to different models of certain manufacturers available in Korea according to an embodiment of the present invention, SIMS spectrum measurement results.
FIG. 3 is a graph showing the relationship between the TOF-F values of inks measured from letters printed as a sample of a document printed with black printer ink (for ink jet) according to different models of various manufacturers available in Korea according to an embodiment of the present invention, SIMS spectrum measurement results.
FIG. 4 is a bar graph showing a fingerprint spectrum and its ion intensity value (a value obtained by standardizing the relative ionic strength of a peak) using the spectrum measurement result of FIG.
5 is a blind testing (Example 1) according to an embodiment of the present invention. The TOF-SIMS spectra of a printer ink stored in a database and letters on a document printed with an unknown printer ink are compared with each other, Thereby identifying the source of the unknown printer ink.
6 is a graph showing another example of TOF-SIMS spectral comparison of characters on a document printed with an unknown printer ink and printer ink stored in a database as blind testing (Example 2) according to an embodiment of the present invention; to be.
7 is a flowchart illustrating a method of detecting TOF-SIMS spectra of a document printer ink according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, A, B, etc. in this specification may be used to describe various components, but the components should not be limited by these terms. Further, the term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . The singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, the terms "comprises" or "having ", and the like, refer to the presence or addition of at least one other feature or number, step, operation, component, Should not be excluded.

The term " fingerprint spectrum " used in the present application refers to a mass value of a component that can be derived from a background component such as paper in a spectrum derived from TOF-SIMS, It means a characteristic mass value excluding a value that can not represent a characteristic.

Hereinafter, the present invention will be described in detail.

The present application proposes a document detection method using TOF-SIMS as a forensic tool for evaluating the homogeneity of the printer inks used in the document for the purpose of forgery or modulation. The printer ink detection method according to an embodiment of the present invention can be applied to a printer ink (for inkjet) of various kinds having different components in the same or similar colors, using a flight time type secondary ion mass spectrometer (non-destructive spectrometer) Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS), the mass spectrum of each component is constructed as a database and used to check the origin of the ink used in the document. It can be used to identify or discriminate whether the ink is homogeneous or forged or falsified.

For example, a transfer contract usually has the same contract in a document printed on a printer device, in which case the components of the printer ink, which are part of each of the two contracts, must match each other, and if they do not match It can be judged that there is a high possibility that one of the contracts has been falsified.

The present invention can be used for efficiently evaluating and analyzing authenticity of a document, authenticity of a document such as a contract or the like, using a non-destructive verification method for printer ink described without damaging a sample (document).

1 is a conceptual diagram for explaining a method of identifying a printer ink on a document according to an embodiment of the present invention. Referring to FIG. 1, a document printed with a printer ink can measure a mass spectrum of ink components in TOF-SIMS. By measuring the mass spectrum for printer ink (for inkjets) that can identify whether the same ink is used in two or more documents, and building a data base for the measured ink spectrum, It is possible to identify unknown ink through an automated verification process (such as identity check, equivalence check, and similarity check) from measuring the spectrum of unknown ink in the document.

In the mass spectrum, ions (primary ions) are irradiated from the ion source such as Bi or Cs on the surface of the sample in the form of pulses, and ions (secondary ions) generated on the surface of the sample reach the detector (Time-of-flight mass spectrometry) using the same principle that mass spectrometry depends on mass, and the time it takes to reach the secondary ion is the same as mass.

At this time, by limiting the amount of primary ion irradiation to 10 ¹³ ions / cm ² or less (static SIMS condition), it is possible to avoid the condition of destroying molecules constituting the surface of the document.

By the irradiation of the primary ions, secondary ions are generated as molecular ions or molecular fragment ions (Molecular Fragmentation Ions). Relative Abundance (RA), ie, relative intensity (Counts), of the material composition or bonding state present on the surface of the document is calculated as spectral values. Here, the unit of mass value is m / z, the ratio of mass (m) to charge (z) based on atomic mass unit (m) and charge (e) of element, sometimes called m / e. For example, the spectrum measurement result may be represented by a graph in which a horizontal axis indicates a mass value and a vertical axis indicates a relative value (ion intensity) to a material composition or a bonding state corresponding to the mass value.

FIG. 2 is a graph showing the relationship between the TOF-F values of inks measured from letters printed as samples of black printer inks (for ink jet printing) according to different models of certain manufacturers available in Korea according to an embodiment of the present invention, SIMS spectrum measurement results. The manufacturer showed typical TOF-SIMS spectra for printer inks of different models (sample numbers # 1, # 2, # 7, # 19, # 22, # 26) , And has a characteristic peak according to the unit mass of charge (m / z) forming the horizontal axis on the spectrum. Here, the intensity of the ions forming the vertical axis represents the relative intensity of forming the ions and is considered to be proportional to the amount of the compound present in the printer ink.

The raw materials used in the printer ink (for inkjet) are mixed with two or more organic and inorganic components, pigments, resins, additives and solvents, and the composition is also referred to as the manufacturer of the printer or the model name of the ink Respectively. That is, it was confirmed that each of the inks represents the mass of each unique characteristic component in the TOF-SIMS spectrum. In particular, inorganic elements contained in the pigment are characterized in the low mass range of mass values below 100 m / z, and peaks related to organic compounds, resins and additives are found in the high mass range of mass values of 100 m / z or more.

By constructing the database with respect to the peak values (relative intensities) of the mass values (m / z) generating the characteristic peaks of the respective inks as described above, compared with the case of building a database with respect to the entire spectrum, And the search time can be improved.

For this purpose, the process of standardizing the peak value is introduced, and the relative intensity of the peak value according to the measurement is changed through a procedure called normalization in which the relative intensity of the peak occurring in each spectrum is divided by the total ion intensity So that the search can be performed with high reproducibility.

In addition, by constructing an ink-specific database of mass ratio values and their relative intensities that do not cause or produce distinctive peaks, it is possible to reduce the required database storage space and improve analysis and search time It can be greatly improved.

FIG. 3 is a graph showing the relationship between the TOF-F values of inks measured from letters printed as a sample of a document printed with black printer ink (for ink jet) according to different models of various manufacturers available in Korea according to an embodiment of the present invention, SIMS spectrum measurement results.

The spectra shown in Fig. 3 were obtained by measuring three spectra of the inks of the printed materials printed with about 86 ink samples (sample number # 29, # 83, # 85) Nos. # 42 and # 74) and one US product (Sample No. # 7).

In the graph of FIG. 3, it can be seen that the position of the peak, i.e., the mass value (m / z) and the relative intensity are different from each other. Therefore, it is possible to distinguish the printer inks from each other from the difference between the characteristic mass ratio of the printer ink and the relative ionic strength.

In other words, since different inks represent different spectra (the mass value (m / z) at which the peak is located, the relative intensity of the peak, etc.), it is checked against the spectrum of the ink sample stored in the database And whether or not the same document is forged or falsified, whether corresponding copies are printed identically, and the like.

The raw materials used for the printer ink (for inkjet) are mixed with two or more organic and inorganic components, pigments, resins, additives and solvents and have different composition ratios, / z).

Magnesium (Mg, mass value 24 m / z), aluminum (Al, mass value of 27 m / z), lithium (Li, mass value 7 m / z), sodium z), potassium (K, mass value 39 m / z), calcium (Ca, mass value 40 m / z) ), Iron (Fe, mass value 56 m / z), nickel (Ni, mass value 58 m / z), cobalt (Co, mass value 59 m / z) Zinc (Zn, mass value 64 m / z) and lead (Pb, mass value 208 m / z). The organic materials and additives include: Aromatic compounds, PDMS, polydimethylsiloxane, phthalates, antioxidants, basic violet, and safflower yellow carthamin.

In addition, the ink may further contain additives to maintain proper viscosity and adhesion, for example, benzyl alcohol, styrene, ethylene glycol, glycerine, etc. .

Using the secondary ions generated by the constituents of the printer ink, the respective printer inks are different from each other according to the manufacturer and the model, and a spectrum having a unique characteristic peak can be obtained.

For example, lithium (Li, mass value 7 m / z) when containing inorganic components, in the case of components with different sizes of peaks (or relative intensity RA) (Mg, mass value of 24 m / z), aluminum (Al, mass value of 27 m / z), silicon (Si, mass value of 28 m / z), potassium K, mass value 39 m / z), phosphorus (P, mass value 31 m / z), calcium (Ca, mass value 40 m / (Cu, mass value 63 m / z), zinc (Zn, mass value 64 m / z), lead (Pb, mass value: 58 m / z), cobalt 208 m / z) and the like.

The aromatic components in the printer ink represent characteristic peaks of cations at mass values of 77 m / z, 91 m / z, 104 m / z and 115 m / z, and characteristic cation peaks of PDMS- Mass values were found at 73 m / z, 147 m / z, 207 m / z, 221 m / z and 281 m / z.

The trimethylated triarylmethane used as the dye had a mass value of 330 m / z, the pentamethylated triarylmethane had a mass value of 357 m / z or 358 m / z, Hexamethylated triarylmethane (basic violet 3) is well characterized at a mass value of 372 m / z or 373 m / z. Saffler yellow carthamin, which is often used as a natural dye, forms a peak at 269 m / z.

The difference in composition according to the manufacturer can not be obtained because each company is not disclosed as a trade secret, but accurate information can not be obtained, but the composition information of the ink due to the analysis of TOF-SIMS can be known.

For example, Sample No. 7 of Company A shows that these components are uniquely contained by forming Na ions, K ions, aromatic peaks, and PDMS peaks, and through the information of spectra displayed with these components, . ≪ / RTI >

For example, Sample No. 29 of Company B contains aromatic peaks, PDMS peaks and 252 ions, and metal ions other than lithium (Li) ions are included. The ink of the product No. C manufactured by Company C has a mass corresponding to an ion having mass values of 243 m / z, 259 m / z, 287 m / z, 331 m / z, 357 m / z and 373 m / As shown in Fig.

FIG. 4 is a bar graph showing a fingerprint spectrum and its ion intensity value (a value obtained by standardizing the relative ionic strength of a peak) using the spectrum measurement result of FIG.

Referring to FIG. 4, by selecting the mass value of characteristic peaks in the TOF-SIMS spectrum of the printer inks as a fingerprint spectrum and dividing it by the total ion intensity of each spectrum, the difference according to the spectrum is minimized, And transformed the TOF-SIMS spectrum into a characteristic, simplified bar graph. Referring to FIG. 4, the fingerprint spectra of the spectrum of the ink and the characteristics of the standardized ion intensity can be more easily determined.

The equivalence refers to similarity between bar graphs, and it can be understood as equivalence to how much information such as mass value and relative intensity are similar.

In a repeated experiment, the equivalence value of the bar graph for the same printer ink was found to be greater than 70%, so if the equivalence value to the bar graphs in the database is greater than 70, the ink of the document is printed with the ink corresponding to that database .

The method of calculating the degree of similarity and the degree of accuracy of the similarity and the mass value between bar graphs (Bar graph format) can be easily understood by a person skilled in the art, so that detailed explanation will be omitted.

7 is a flowchart illustrating a method of detecting TOF-SIMS spectra of a document printer ink according to an embodiment of the present invention. A method of detecting ink on a document will be described in more detail with reference to FIG.

The step of obtaining the ink spectrum of the sample includes a step of determining the printing position of the character in the document to be sensed (S105), a TOF-SIMS Measuring the spectrum (S110), and measuring the TOF-SIMS spectrum (S120) for the printer ink character portion. The steps S105, S110, and S120 may be performed by changing the order of the sequence as necessary.

The reason why the spectrum of the background like the white paper portion is measured in S110 is that the mass of the component detected in the background portion is referenced to the mass derived from the printer ink so that the characteristic mass value inherent in the ink is included . Specifically, a TOF-SIMS spectrum of a paper portion as a background of a document is measured, and a secondary ion mass spectrum is obtained by focusing the printed printer ink on the document under TOF-SIMS. As a result, Information on molecules such as sonar and organic matter can be obtained.

After the steps S105, S110, and S120 are performed, the mass of the background is removed from the spectrum of the printed printer ink, and the spectrum of the printer ink itself is obtained (S130).

A fingerprint spectrum (mass values corresponding to fingerprint peaks) having mass spectral characteristics of a sample (ink in the document) to be used as a search key of a database or a library is selected from the spectrum passed through S130 (S140 ).

At this time, a corresponding pattern existing in all or a part of the sample mass spectrum may be selected by a key, or at least one mass value predetermined in the ink sample mass spectrum may be selected by a search key.

The relative ion intensities of the characteristic peaks of the sample selected by the search key of the database are divided by the total ion intensities of the spectra, and normalization is performed in order to minimize the variation of the ion intensities according to each spectrum (S150). The ionized intensity of the characteristic peaks may be classified according to the magnitude of the ion, and the intensity of the ions may be used as an element for distinguishing the different kinds of the print inks (S160).

Then, a bar graph of a print ink sample having an equivalence of a predetermined value or more in the database is searched for the selected search key (S170). At the time of the search (S170), a similar bar graph can be searched based on the value at a specific mass at which the peak occurs or the relative intensity of the peaks classified. The database or the library may be constructed from mass spectra of various print ink samples obtained in the same or similar manner as the measurement of the sample mass spectrum.

Finally, the retrieved result (whether or not the print ink sample is found, information of the found ink sample, etc.) is output (S180). Information on the degree of equivalence may be output along with the searched result.

By using the above-mentioned method of identification, it is possible to identify the printer ink component on a document by using TOF-SIMS spectroscopy, which is a non-destructive analysis method, as a forensic tool for evaluating the printer ink used for writing documents for the purpose of falsification or modulation have. Using various TOF-SIMS mass spectrometry techniques for various types of printer inks made from the same black but different manufacturers, the components of the printer ink surface of the document are analyzed precisely, Can be used to compare and analyze the components of the printing ink used in the document to determine the product manufacturing source and model name of the used printing ink.

Further, it is possible to determine whether or not the document is falsified by checking the information related to the identity of the preparation time or the like in accordance with the degree of volatilization of the volatile organic compound in the printing ink, so that it can be utilized for judging and discriminating document falsification.

In the following experiments, a TOF-SIMS spectrum was measured using a TOF-SIMS 5 system of ION-TOF. The TOF-SIMS 5 system is equipped with a 25 keV, Bi ⁺ liquid metal ion gun with an ion beam current of 1 pA, a primary ion ion pulse size of 0.7 ns, a secondary ion generated by the primary ion of 3.0 keV, and the secondary ion was measured after the energy difference was corrected by reflection optics.

In the blind experiment, we analyzed the fingerprint spectrum of the printer ink stored in the database and the letters on the document printed with the unknown printer ink to evaluate the equality condition, and the origin of the unknown printer ink was examined.

( Example  One)

The TOF-SIMS spectrum of the printer ink stored in the database and the letters on the document printed with the unknown printer ink were measured to obtain a bar graph showing the standardized ionic strength of the fingerprint spectrum. The results are shown in Fig. 5 (A).

5 shows the standardized TOF-SIMS spectra of the printer ink stored in the database together with the standardized data of the characters on the document printed with the unknown printer ink of Example 1.

The printer ink sample (B) has an equivalence value of 84.4, the printer ink sample (C) has an equivalence value of 67.7, and the printer ink sample The ink sample (D) showed an equivalence value of 52.9, the printer ink sample (E) had an equivalence value of 49.0, and the printer ink sample (F) had an equivalence value of 42.2. In this case, the unknown printer ink (A) can be concluded that the ink (A) matches the printer ink sample (B) having an equivalence value of 70 or more and the highest equivalence value.

That is, by measuring the TOF-SIMS spectrum of the unknown printer ink (A) and comparing the converted (standardized) bar graph results with the bar graphs of the printer inks on the document stored in the database, (Origin, manufacturer, product model, serial number, etc.) and components for the unknown printer ink.

( Example  2)

The TOF-SIMS spectrum of the printer ink stored in the database and the letters on the document printed with the unknown printer ink were measured to obtain a bar graph showing the standardized ionic strength of the fingerprint spectrum. The results are shown in Fig. 6 (A).

FIG. 6 shows the standardized TOF-SIMS spectra of the printer ink stored in the database together with the standardized data of characters on the document printed with the unknown printer ink of Example 1.

The printer ink sample (B) has an equivalence value of 85.2, the printer ink sample (C) has an equivalence value of 69.5, and the printer ink sample The ink sample (D) showed an equivalence value of 64.6, the printer ink sample (E) had an equivalence value of 62.2, and the printer ink sample (F) showed an equivalence value of 58.8.

As a result of this equality test, it can be determined that the printer ink B having an equivalence value of 70 or more and having the largest equivalence value corresponds to the unknown printer ink A.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (14)

Measuring a mass spectrometry spectrum of a paper portion and a character portion of a document sample, and obtaining an ink spectrum of the sample by excluding the spectrum of the paper portion from the spectrum of the character portion;
Obtaining a fingerprint spectrum corresponding to a mass value of a peak characteristic of the ink from the ink spectrum;
Calculating a value of the ion intensity of the fingerprint spectrum by dividing the relative ion intensity of the peak corresponding to the fingerprint spectrum by the total ion intensity of the spectrum of the ink;
Classifying the ion intensity values for classifying the fingerprint spectra with priority given to the ion intensity value of the fingerprint spectrum;
Retrieving data satisfying an equivalence condition with a search key of the ink including the fingerprint spectrum and the ion intensity value from the spectrum database for the printer ink; And
And outputting information on the origin of the ink that is found to satisfy the equivalence condition from the database,
The mass spectrometry spectrum of the sample and the database is a time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectrum,
Wherein the step of retrieving the data is to retrieve data for a printer ink satisfying an equivalence condition with the database from a value having a larger ionic strength value among the classified fingerprint spectra. The method according to claim 1,
Wherein the step of obtaining the ink spectrum of the sample further comprises a step of selecting a position to measure the spectrum of the character portion in the sample before the spectrum of the character portion is measured,
Wherein the step of selecting the position of the character part is a step of searching for a position of a character part to be subjected to spectral measurement by using pattern matching or using a font of a character described in ink in a document. The method according to claim 1,
Wherein a fingerprint spectrum of the sample has a peak within a mass value range of 0 to 400 m / z. delete The method according to claim 1,
Wherein the primary ion used in the flying-type secondary ion mass spectrometry is selected from an ion source comprising Bi and Cs. 6. The method of claim 5,
Wherein the amount of said primary ions irradiating said sample is not more than 10 < ¹³ > ions / cm < ² >. The method according to claim 1,
Wherein the fingerprint spectrum has a mass value of less than or equal to 100 m / z, and wherein the fingerprint spectrum is a mass value corresponding to inorganic elements contained in the ink. The method according to claim 1,
Wherein the fingerprint spectrum has a mass value of greater than 100 m / z, and wherein the fingerprint spectrum is a mass value corresponding to an organic compound, a regimen, or an organic additive contained in the ink. The method according to claim 1,
Wherein the equivalence condition is that the equivalence value between the search key of the ink and the data of the database corresponding thereto is 70 or more. An irradiating unit for irradiating a primary ion of each of a paper portion and a letter portion of a sample which is a document;
A measuring unit for measuring a flying type secondary ion mass spectrometry spectrum by accelerating and detecting the binary difference formed by the primary ions;
A first arithmetic unit for obtaining a spectrum of the ink using the letter partial spectrum and the paper partial spectrum of the sample measured by the measurement unit;
A second arithmetic unit for obtaining a fingerprint spectrum corresponding to a mass value of the peak from the spectrum of the ink;
A third order arithmetic unit for obtaining an ion intensity value of the fingerprint spectrum through a standardization process of dividing the relative ion intensity of the peak corresponding to the fingerprint spectrum of the ink by the total ion intensity of the ink spectrum;
A quaternary operation unit for classifying the fingerprint spectra with priority given to the ion intensity value of the fingerprint spectrum;
A search unit for comparing the fingerprint spectrum and its ion intensity value with values corresponding to a search key of a spectral database for a printer ink to search for whether the equivalence condition is satisfied; And
And a display unit for outputting the information on the origin of the ink as a result derived from the retrieval unit,
Wherein the retrieving unit retrieves data for a printer ink satisfying an equivalence condition with the database from a value having a larger ionic strength value among the classified fingerprint spectra. The method of claim 10, wherein
Wherein the fingerprint spectrum of the sample is within a mass value range of 0 to 400 m / z. 11. The method of claim 10,
Wherein the primary ion used in the flying-type secondary ion mass spectrometry is selected from an ion source comprising Bi and Cs. 12. The method of claim 11,
Wherein the fingerprint spectrum has a mass value of less than or equal to 100 m / z, and wherein the fingerprint spectrum is a mass value corresponding to the inorganic elements included in the ink. 12. The method of claim 11,
Wherein the fingerprint spectrum has a mass value of greater than 100 m / z, and wherein the fingerprint spectrum is a mass value corresponding to an organic compound, a regimen, or an organic additive contained in the ink.

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