(12) Patent Application Publication (10) Pub. No.: US 2014/0116474 A1 Lawandy (43) Pub
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US 201401 16474A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2014/0116474 A1 LaWandy (43) Pub. Date: May 1, 2014 (54) SUPERCRITICAL FLUID CLEANING OF Publication Classification BANKNOTES AND SECURE DOCUMENTS (51) Int. Cl. (71) Applicant: Nabil M. Lawandy, Saunderstown, RI BOSB 3/04 (2006.01) (US) (52) U.S. Cl. CPC ........................................ B08B3/04 (2013.01) (72) Inventor: Nay M. Lawandy, Saunderstown, RI USPC ............................................. 134/34; 134/184 US (57) ABSTRACT (73) Assignee: SPECTRA SYSTEMS CORPORATION, Providence, RI (US) A method and system for cleaning a secure instrument, Such s s as a banknote, including a Substrate, visual data and a security (21) Appl. No.: 14/021,603 feature, including exposing the secure instrument to a Super y x- - - 9 critical fluid at a temperature and a pressure and for a duration 1-1. Sufficient to clean the Substrate and not compromise the Secu (22) Filed: Sep. 9, 2013 rity feature and the visual data, wherein to clean the substrate O O includes to remove one or more Substances from the Substrate Related U.S. Application Data into the supercritical fluid. The substances removed from the (60) Provisional application No. 61/721,296, filed on Nov. Substrate may include contaminants, dirt, sebum and patho 1, 2012. genS. Unfit notes after SCFC Fit notes with no Shredd ing tears and soiling below a set level notes with no tears and soiling above a Set eve Super Critical Fluid (e.g., CO.) Cleaning Patent Application Publication May 1, 2014 Sheet 1 of 14 US 2014/0116474 A1 10,000 1.000- 1 supercritical : fluid OO critical point O 200 250 300 350 400 Temperature (K) FIG. 1 Patent Application Publication May 1, 2014 Sheet 2 of 14 US 2014/0116474 A1 six: hiding Agitation: 3i: Site Supercritical Fid 83; the Recitiate astictii FIG. 2 Patent Application Publication May 1, 2014 Sheet 3 of 14 US 2014/0116474 A1 Satg Ceafig as it: Stipe critica Fiji C3:er Recificiate assig FIG. 3 Patent Application Publication May 1, 2014 Sheet 4 of 14 US 2014/0116474 A1 Unfit notes after SCFC Fit notes with no Shredding tears and soiling below a set level notes with no tears and soiling above a Set eve Super Critical Fluid (e.g. CO.) Cleaning FIG. 4 Patent Application Publication May 1, 2014 Sheet 5 of 14 US 2014/0116474 A1 Patent Application Publication May 1, 2014 Sheet 6 of 14 US 2014/0116474 A1 8 s s .3. s 3. X after app$ication of seisit s 8. s after supercritica: CR ceasig . s w : . s SS Wawelength inst FIG. 7B Patent Application Publication May 1, 2014 Sheet 8 of 14 US 2014/0116474 A1 Patent Application Publication May 1, 2014 Sheet 9 of 14 US 2014/0116474 A1 FIG. 10A Uncircuiated pote es s c after sugercritcai CO ceaning s cated with restorii r g s N es sa s SS Waveiength, it FIG. 10B Patent Application Publication May 1, 2014 Sheet 10 of 14 US 2014/0116474 A1 388: :::::: :".............................................................................." 388 to 8 38: to 38:8 x 3333:33:38 :::::::::: E: w838::::::::::::::::::: 8:3 Patent Application Publication May 1, 2014 Sheet 11 of 14 US 2014/0116474 A1 3S $5. RSS38 RSS38. iS$383 53 Ripsa Sect3tity Seax: FIG. 12 Patent Application Publication May 1, 2014 Sheet 12 of 14 US 2014/0116474 A1 Risies Security Fibers (Red FIG. 13 0 Year: &Yeargi: FIG. 14 Patent Application Publication May 1, 2014 Sheet 13 of 14 US 2014/0116474 A1 &: 8x888ssor Patent Application Publication US 2014/0116474 A1 before SCCO2 after SCCO2 F.G. 17A FIG. 17B US 2014/0116474 A1 May 1, 2014 SUPERCRITICAL FLUID CLEANING OF ematically, microprinting, digital watermarks, magnetic inks BANKNOTES AND SECURE DOCUMENTS and threads, demetalized security threads, holographic fea tures, fluorescent inks, lenticular lens array security threads, CROSS-REFERENCE TO RELATED and fluorescent and non-fluorescent security threads. APPLICATIONS 0007 High level covert security features include 0001. This application claims priority to U.S. provisional ENIGMA (De La Rue International) and M (Geiseke and application Ser. No. 61/721,296, filed Nov. 1, 2012. DeVrient). An important security feature in currency is the M feature, where “M” refers to “machine readable.” The M TECHNICAL FIELD feature is a colorless, inorganic oxide integrated into the paper Substrate, the printing ink, security ink, or a security thread, 0002 The present invention relates generally to the clean without causing any change in the appearance of the ban ing of secure documents such as banknotes without inducing knote. The powdered M feature may be blown into the paper damage thereof. More specifically, the present invention Substrate in a trail to identify a particular banknote denomi relates to the use of Supercritical fluids to clean secure docu nation. When exposed to a flash from a strong source of light, ments or banknotes without damaging their visual data, inks, the M feature emits a band of light in a split second that substrates or security features. The process is also effective in rapidly disappears. This repeatable, characteristic light band disinfecting the secure documents or banknotes. of the banknote can be authenticated by a reading device. The central banks protect the security of the Mfeature by requir BACKGROUND OF THE INVENTION ing the use of special sensors to recognize it. 0003 High security documents such as banknotes have 0008. As counterfeiters have become more sophisticated, substrates formed from various materials. In the United the security features in Such documents have had to become States, paper currency is made from a non-woven combina more advanced as well in order to prevent widespread fraud. tion of 75% cotton and 25% linen fibers. In most other coun As the Substrates of Such secure documents have become tries, pulp-based substrates are used. Some countries, such as more advanced, the cost to produce them has also increased, Canada, have used cotton and paper blended banknotes. In thus making the replacement of worn currency quite expen addition, countries such as Australia, New Zealand and sive. Therefore, it is important that in addition to being secure, Canada have issued banknotes having polymer Substrates, such documents must have a high level of durability. e.g., Substrates including biaxially oriented polypropylene. 0009 Banknotes are removed from circulation for a vari The substrate, which may include one or more plies of the ety of reasons. Based on one study, 81% of notes are removed Substrate material, may include security features such as because of Soiling, 9% are removed because of damage laminated polymer or papersecurity threads, planchettes, and caused by mechanical means, especially tearing, 5% are watermarks formed directly into the substrate. For example, removed because of graffiti on the notes, 4% are removed U.S. paper currency contains Small segments of red and blue because of general wear and tear, and 1% are removed fibers scattered throughout for visual identification. because of damage to the security elements. Generally, 60% 0004 Banknotes also include visual data printed on the to 80% of all rejected bank notes result from to soiling. Substrates. The visual data may include images such as por 0010 Banknotes have a finite time in circulation due to traits, authentication information Such as serial numbers, or Soling and tearing of the notes in use by the public. For both. The inks used to print on the substrates may include example, it takes about 4,000 double folds (first forward and special dry color pigments blended with oils and extenders then backward) before a U.S. paper bill will tear. Banknotes and phosphor chips containing layered micro-interference are handled in many ways during their usable life and expe layers. Suchinks include Flexo inks, gravure inks, and thicker rience a variety of mechanical stresses, as well as being intaglio inks. brought into contact with Substances that can dirty the notes, 0005 High security documents such as banknotes are gen resulting in difficulty in their authentication and use. One of erally formed on substrate materials that are frequently the major determinants of the banknote life, which is shortest equipped with security elements, which are difficult to imitate for the lowest denominations, is soiling. Work by the Dutch and which permit even a layman to check the authenticity of National Bank has shown that the primary source of soiling is the printed information or the document. Security elements deposited sebum following contact with fingers, which can be, for example, windowed security threads, which are sebum eventually oxidizes and becomes yellow. Further, a visible in certain areas on the surface of the banknote, applied study by the Microbiology Department of Karachi University foils, which have a transparent or metallized embossed holo in Pakistan concluded that currency notes could also carry gram, blind embossings, so-called “latent images' produced contaminants that cause diarrhea and urinary tract infections, by printing technology or by printing and embossing technol in addition to skin burning and septicaemic infection. One ogy, which render different information from different view study found that 26% of notes contained high levels of bac ing angles, prints containing optically variable pigments and teria, and 80% of notes had some traces of bacteria. An even producing different color effects depending on the viewing more concerning finding was that pathogens, including bac angles, and prints comprising metallic effect ink, which have teria and viruses, on banknotes have the potential to develop metallic luster, for example, in a gold, silver or bronze tone. In resistance to antibiotics, making the treatment of infectious addition to these unaided features, there are quasi-public diseases more difficult. security threads, fibers and inks, which fluoresce orphospho 0011 Such “dirty' money is not simply confined to devel resce under illumination with ultraviolet (“UV) or infrared oping nations.