# US 7,897,922 B2 · Radiometric measuring of thin fluid films > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,897,922 B2 - Document ID: US7897922B2 - Status: Granted - Kind: B2 - Application number: 10/443,026 - Filed: 2003-05-22 - Published: 2004-01-08 - Granted: 2011-03-01 - Earliest claimed: 2000-11-24 - Assignees: MicroFluid AB - Inventors: Leif Cronvall - Web page: https://patentgrep.com/patent/US7897922B2 ## CPC - G01B 11/06: for measuring thickness {; e.g. of sheet material (thickness measurement by thermal means G01B21/085)} - B41F 33/0063: {Devices for measuring the thickness of liquid films on rollers or cylinders} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - B41F: PRINTING MACHINES OR PRESSES (manifolding devices or office printing machines B41L) ## Abstract The present invention relates to radiometric measurement of a thin fluid film using absorption of IR radiation. At least one IR radiator is directed to send signals to an IR detector via a bed on which the fluid film is placed. The IR detector is set to receive IR radiation in a band around a characteristic absorption band of the fluid of the fluid film. The invention is developed for printing presses, where the thickness of fountain solution on the printing plate and the proportion of printing ink in an emulsion of printing ink and fountain solution may be controlled. ## Claims ### Claim 1 A method for radiometric measurement of thin fluid films where absorption of IR radiation is used, the method comprising: directing at least one IR radiator to send signals to a connected IR detector by means of the fluid film to be measured, wherein the method is used for a printing press and the fluid film comprises fountain solution or an emulsion of fountain solution and printing ink, received on a printing plate; wherein several points of measurement are monitored and the power of IR radiation in at least one of the points of measurement is set in relation to a specific printing ink. ### Claim 2 (depends on 1) The method according to claim 1, wherein the printing press is an offset press. ### Claim 3 (depends on 1) The method according to claim 1, wherein the proportion of ingredients of the emulsion of fountain solution and printing ink is measured and the measurement is related to measurement of the thickness of the fluid film, the fluid film being constantly monitored, the supply of fountain solution and or printing ink being adjusted in view of the measurements. ### Claim 4 (depends on 1) The method according to claim 1, wherein the signals from the at least one IR detector are supplied to a control unit. ### Claim 5 (depends on 4) The method according to claim 4, wherein signals of an angle sensor and a density meter are given to the control unit and the signals from related detectors, sensors and meters are processed in the control unit to control the supply of fountain solution and/or printing ink. ### Claim 6 (depends on 5) The method according to claim 5, wherein the signal is pulsated or continuous, the measurements are presented in real time or after processing of the measurements, the IR radiator sends IR radiation in a broad or narrow range, one or more filters are placed at the IR detector or IR radiator to limit the received IR radiation to a band and the absorption band is the main absorption band of the fluid to be measured. ### Claim 7 (depends on 1) The method according to claim 1, wherein an IR spectrometer is used. ### Claim 8 (depends on 1) The method according to claim 1, wherein a characteristic absorption band of the fluid of the fluid film is first determined and the wavelength of the IR radiation to be received by the IR detector is set to a band in a range where the fluid or separate ingredients of the fluid has significant absorption. ### Claim 9 (depends on 8) The method according to claim 8, wherein the characteristic absorption band is determined by means of spectral analysis and the IR range set to be received by the IR detector corresponds to a major part of the chosen characteristic absorption band of the fluid. ### Claim 10 A device for radiometric measurement of thin fluid films where absorption of IR radiation is used, comprising: at least one unit comprising an IR radiator and an IR detector; a signal processing system and other support systems provided at a printing press, wherein the at least one unit measures on a non-printing area and a printing area of the printing plate; a control unit for receiving information from further sensors or meters; wherein several points of measurement are monitored and the power of IR radiation in at least one of the points of measurement is set in relation to a specific printing ink. ### Claim 11 (depends on 10) The device according to claim 10, wherein the at least one unit is fixed or movable. ### Claim 12 (depends on 11) The device according to claim 11, wherein the at least one unit comprises an IR spectrometer. ### Claim 13 (depends on 10) The device according to claim 10, wherein the measurements are presented locally. ### Claim 14 (depends on 10) The device according to claim 10, wherein a separate unit is used for each point of measurement. ### Claim 15 (depends on 10) The device according to claim 10, wherein controllers for delivery of fountain solution and printing ink are connected to the control unit.