# US 2020/0399834 A1 · Paper substrates incorporating covert marking pigments, and processes for obtaining and using same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0399834 A1 - Document ID: US20200399834A1 - Status: Published application - Kind: A1 - Application number: 16/450,320 - Filed: 2019-06-24 - Published: 2020-12-24 - Earliest claimed: 2019-06-24 - Assignees: International Paper Company - Applicants: International Paper Company - Inventors: David Verd Reed; Matthew James Bovee; James D. Regel; Benny Joe Skaggs; Maria A. Dannemiller - Web page: https://patentgrep.com/patent/US20200399834A1 ## CPC - D21H 21/48: Elements suited for physical verification, e.g. by irradiation - B42D 25/21: for multiple purposes - B42D 25/382: absorbing or reflecting infrared light - D21H 19/38: characterised by the pigments - D21H 19/385: {Oxides, hydroxides or carbonates} - D21H 21/16: Sizing or water-repelling agents - D21H 23/78: Controlling or regulating not limited to any particular process or apparatus - G01N 21/64: Fluorescence; Phosphorescence - G07D 7/12: Visible light, infrared or ultraviolet radiation - G07D 7/1205: Testing spectral properties - G07D 7/2033: Matching unique patterns, i.e. patterns that are unique to each individual paper - D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR - B42D: BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G07D: HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING ## Abstract Paper substrates which incorporate covert marking pigments (CMPs) which are one or more infrared (IR) anti-Stokes pigments. Also, processes for incorporating such CMPs into a paper substrate other than by a printing technique, such as, for example, by using a size press or spraying, as well as processes for identifying the presence of such CMPs incorporated into a paper substrate sheet with an infrared (IR) pigment sensor of, for example, a copier or printer for the purpose of adjusting the quantity of printer pigment deposited on a paper substrate sheet or to determine whether the paper substrate sheet is an authentic or counterfeit document. ## Claims ### Claim 1 A covertly marked paper substrate article comprising: a paper substrate; and a covert marking pigment having a particle size in the range of from about 0.1 to about 5 microns and being incorporated into the paper substrate in a IR detectable amount of from about 0.1 to about 1,000 mg/m2, the covert marking pigment being one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; Gadolinium (Gd2O2S); Ytterbium (Yb); or mixtures thereof. ### Claim 2 (depends on 1) The article of claim 1, wherein the covert marking pigment is incorporated into the paper substrate in an IR detectable amount of from about 2 to about 10 mg/m2. ### Claim 3 (depends on 1) The article of claim 1, wherein the IR anti-Stokes shift pigments are selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; Gadolinium (Gd2O2S); or Ytterbium (Yb). ### Claim 4 (depends on 1) The article of claim 1, wherein the covert marking pigment is distributed randomly in the paper substrate. ### Claim 5 (depends on 1) The article of claim 1, wherein the paper substrate has two outer surfaces and wherein the covert marking pigment is applied to one of the two outer surfaces. ### Claim 6 (depends on 1) The article of claim 1, wherein the paper substrate has two outer surfaces and wherein the covert marking pigment is incorporated below the two outer surfaces. ### Claim 7 (depends on 1) The article of claim 1, which is in the form of a ream of paper substrate sheets, at least a portion of the ream comprising covertly marked paper substrate sheets. ### Claim 8 (depends on 7) The article of claim 7, wherein the covertly marked paper substrate sheets in the ream comprise from one in three to from one in five paper substrate sheets in the ream. ### Claim 9 (depends on 7) The article of claim 7, wherein the paper substrate sheets have two opposed side edges, and wherein the cover marking pigment is incorporated on one of the side edges of each covertly marked paper substrate sheet in the ream. ### Claim 10 (depends on 1) The article of claim 1, wherein the paper substrate includes an optical brightening agent. ### Claim 11 A process for preparing a covertly marked paper substrate, the process comprising the following steps: (a) providing a composition having a covert marking pigment having a particle size in the range of from about 0.1 to about 5 microns, the covert marking pigment being one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; Gadolinium (Gd2O2S); Ytterbium (Yb); or mixtures thereof; and (b) incorporating the composition of step (a) by a non-printing technique into a paper substrate in an IR detectable amount of from about 0.1 to about 1,000 mg/m2. ### Claim 12 (depends on 11) The process of claim 11, wherein the composition of step (a) comprises a size press composition which further comprises a sizing agent, and wherein the size press composition is incorporated into the paper substrate in step (b) at a size press. ### Claim 13 (depends on 11) The process of claim 11, wherein the covert marking pigment is incorporated into the paper substrate during step (b) in an IR detectable amount of from about 2 to about 10 mg/m2. ### Claim 14 (depends on 11) The process of claim 11, wherein the IR anti-Stokes shift pigments of step (a) are selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; Gadolinium (Gd2O2S); or Ytterbium (Yb). ### Claim 15 (depends on 11) The process of claim 11, wherein step (b) is carried out by randomly distributing the covert marking pigment in the paper substrate. ### Claim 16 (depends on 11) The process of claim 11, wherein the paper substrate of step (b) has two outer surfaces and wherein the covert marking pigment is applied to one of the two outer surfaces during step (b). ### Claim 17 (depends on 11) The process of claim 11, wherein the paper substrate of step (b) is formed into a ream of paper substrate sheets, and wherein from one in three to from one in five paper substrate sheets in the ream are covertly marked paper substrate sheets. ### Claim 18 (depends on 17) The process of claim 17, wherein the paper substrate of step (b) has two opposed side edges, and wherein the cover marking pigment is incorporated on one of the side edges of each covertly marked paper substrate sheet in the ream. ### Claim 19 A process for adjusting the amount of printer pigment deposited on a paper substrate sheet, the process comprising the following steps: (a) providing a covertly marked paper substrate sheet, the covertly marked paper substrate sheet comprising: a paper substrate sheet; and a covert marking pigment having a particle size in the range of from about 0.1 to about 5 microns and being incorporated into the paper substrate sheet in an IR detectable amount of from about 0.1 to about 1,000 mg/m2 and in a manner which identifies a type of covertly marked paper substrate sheet, the covert marking pigment being one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; Gadolinium (Gd2O2S); Ytterbium (Yb); or mixtures thereof; and (b) scanning a paper substrate sheet with an IR pigment sensor to adjust the quantity of printer pigment deposited on the of covertly marked paper substrate sheet in response to identify the type of covertly marked paper substrate sheet; and (c) adjusting the quantity of printer pigment deposited on the of covertly marked paper substrate sheet in response the type of covertly marked paper substrate sheet identified in step (b). ### Claim 20 (depends on 19) The process of claim 19, wherein the paper substrate sheet of step (a) has two outer surfaces and wherein the covert marking pigment is applied to one of the two outer surfaces, and wherein IR pigment sensor of step (b) scans the outer surfaces of each of the paper substrate sheets of step (a). ### Claim 21 (depends on 19) The process of claim 19, wherein each paper substrate sheet of step (a) has two opposed side edges, and wherein the covert marking pigment is applied to one of the two side edges of each covertly marked paper substrate sheet, and wherein IR pigment sensor of step (b) scans the side edges of each of the paper substrate sheets of step (a). ### Claim 22 (depends on 19) The process of claim 19, wherein the covert marking pigment is incorporated into the paper substrate sheets of step (a) is in an IR detectable amount of from about 2 to about 10 mg/m2. ### Claim 23 (depends on 19) The process of claim 19, wherein the IR anti-Stokes shift pigments of step (a) are selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; Gadolinium (Gd2O2S); or Ytterbium (Yb). ### Claim 24 (depends on 19) The process of claim 19, wherein the covert marking pigment is distributed randomly in the paper substrate sheets of step (a). ### Claim 25 (depends on 19) The process of claim 19, wherein the paper substrate sheets of step (a) are formed into a ream of paper substrate sheets, and wherein from one in three to from one in five paper substrate sheets in the ream are covertly marked paper substrate sheets. ### Claim 26 A process for determining whether or not a paper substrate sheet is an authentic document, the process comprising the following steps: (a) providing a paper substrate sheet; and (b) scanning the paper substrate sheet with an IR pigment sensor to detect whether or the paper substrate sheet incorporates a specified covert marking pigment, the covert marking pigment being one or more IR anti-Stokes shift pigments selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; lanthanum fluoride; yttrium oxysulfide; lanthanum oxysulfide; Gadolinium (Gd2O2S); Ytterbium (Yb); or mixtures thereof; wherein if the IR pigment sensor detects that the paper substrate sheet: (i) does incorporate the specified covert marking pigment, the paper substrate sheet is identified as authentic; or (ii) does not incorporate the specified covert marking pigment, the paper substrate sheet is identified as counterfeit. ### Claim 27 (depends on 26) The process of claim 26, wherein each paper substrate sheet of step (a) have two outer surfaces, and wherein each paper substrate sheet which is an authentic document incorporates the specified covert marking pigment into the paper substrate sheet below the two outer surfaces. ### Claim 28 (depends on 26) The process of claim 26, wherein the covert marking pigment is distributed randomly in the paper substrate sheets of step (a). ### Claim 29 (depends on 26) The process of claim 26, wherein the IR anti-Stokes shift pigments of step (a) are selected from one or more of: yttrium oxide; sodium yttrium fluoride; lanthanum oxide; Gadolinium (Gd2O2S); or Ytterbium (Yb).