METHOD OF DYEING DOCUMENTS ON ATTEMPTED THEFT AND DEVICE FOR IMPLEMENTING SUCH METHOD

Abstract: A method and device for staining documents, e.g. banknotes (12), kept in a space protected against theft, such as a container (10), by means of a dye containing finely ground pigment on the attempted theft of the documents. Inside the container are separate capsules (14) for the storage of two individual dye components (22, 24) - containing among other substances a resin or other binding agent, and a hardener or similar setting agent - selected for their ability to form a two-component dye. At least one of the capsules is fitted with an actuator (16) so designed that when the container is tampered with or is otherwise subjected to conditions for which it is not intended it will force the component stored in the capsule out under pressure into a mixing chamber (28). The chamber is provided with an outlet of fine holes or channels (34), through which the two-component dye, now ready for use, can be expelled, also under pressure, for the purpose of dyeing the said documents. It is suitable to design the capsule in the form of a cylinder and the actuator in the form of a piston enclosed therein driven forward by an explosive charge (18).

Description: Method of Dyeing Documents on Attempted Theft and Device for Implemen ing such Method The present invention concerns a method and device for staining docu¬ ments, e.g. banknotes, kept in a space protected against theft, such as a container, by means of a dye containing finely ground pigment if an attempt is made to steal the documents. The use of various types of dye is already familiar, in particular a red dye, which may contain finely ground pigment or some dyestuff held in solution, for the purpose of staining theft-prone articles, which might be banknotes for example, at the moment when a theft is attempted. As a result of being stained with the red dye the banknotes become extremely conspicuous and, since they can therefore no longer be used, are of little value to a thief. A major problem encountered in methods of staining known hitherto has been the possibility of * being able to remove the reά dye under certain conditions. Thus, previously, water-soluble dye of conventional type is known to have been removed — washed-off — before it was completely dry. Naturally, such dye removal demands the utmost dexterity and care, but cases are known in which the final result was nevertheless banknotes fully usable in practice. By the use of certain chemicals and solvents, and by bleaching, it has also proved possible to remove all traces of the dye even after it has dried. A major objective of the invention is thus to achieve a method of staining documents such as to render it entirely impossible to remove the dye without destroying the document itself. Examination of the coloration and composition of the inks used for printing banknotes revea-ls that the colouring agent or dyestuff used is bound to the surface of the notes by resins. However, the process nec¬ essary for achieving the desired coloration is both time-consuming and complicated. The ink contains a number of different components and requires a drying time * of approximately forty hours. One of the more important principles in the realization of the invention is the use of a dye which, when used for the purpose of staining bank¬ notes with a conspicuous dye on the attempted theft of the notes, will be bound to the notes or documents in the same manner as the ink nor¬ mally used in printing them. However, it is quite impossible to use the actual banknote ink for this purpose since such a long time would then be required for the ink to dry. Before 40 hours were up a "specialist" would easily be able to force open the anti-theft container and remove the still-wet ink from the notes. Clearly, therefore, a dye suitable for the present purpose, which will remain permanently bound to the banknotes, must also be able to dry very rapidly. Dyes of this type are, however, .difficult to handle. There is a real danger of premature drying during storage and of the undesirable separation of the individual components of the dye; as a result the dye deteriorates and cannot be used at exactly the moment when it is re¬ quired to stain the documents. A further objective of the invention is thus to achieve a method of dyeing documents in which the dye used is always ready for instantaneous use in the dyeing process. The desired objectives of the invention are achieved in the context of a method of the type indicated in the introductory paragraph, such method being primarily characterized in that two components selected for their ability to combine to form a quick-drying, two-component dye — con¬ taining among other substances a resin or other binding agent, and a hardener or similar setting agent — are stored separately inside the container, such that when the container is tampered with or otherwise subjected to conditions for which it is not intended they will be com¬ bined and mixed under high pressure, brought about by one or more ex¬ plosive charges, the two-component dye being thereafter sprayed over the documents. If the desired effect is to be achieved it is imperative for the dye to dry within three minutes at the most, and yet not start to thicken before thirty seconds; and it is also desirable that the dye, or at least one of its individual components, contain some agent for the reduction of surface tension so as to enable the dye to permeate the banknotes as thoroughly as possible by means of the capillary forces acting in and between the banknotes. The agent for the reduction of surface tension can be conveniently contained in one of the capsules along with a component of the dye. Clearly, apart from the components already discussed, the capsules may also contain other components such as solvents for the resin, etc. The realization of the new method is brought about in that the invention provides for a device characterized particularly in that separate cap¬ sules are mounted inside the container for the individual components of the dye and that at least one of the capsules is fitted with an actuator so designed that when the container is tampered with or otherwise sub¬ jected to conditions for which it is not intended it will force the component stored in the capsule out under pressure into a mixing chamber having an outlet of small holes or nozzles through which the two-component dye, now ready for use, is. expelled. It is essential that the dye be applied to or permeate the documents as rapidly as possible after initiation of the dyeing process. Thus, if application is too slow the container might perhaps be "guillotined", meaning that the dyeing mechanism would be separated from the container before it had a chance to come into function. A period of no more than a few tenths of a second might be mentioned as an indication of the amount of time in which the entire dyeing process should be reckoned; preferably no more than four hundredths of a second should be needed. To complete the process as rapidly as this a very high pressure must be built up O PI over a short period of time. A suitable method of achieving this is, for example, to provide for the capsule to take the form of a cylinder and the actuator the form of a piston enclosed therein driven forward by an explosive charge. An arrangement of this nature is described in greater detail in Swedish patent no. 7704195-2. Other devices for building up the required pressure may also be applied in the present context, e.g. a mechanically operated spring device, a carbon dioxide cartridge, or other similar device. A preferred embodiment of the invention will be described in greater detail in the following paragraphs with reference to the appended drawing. The drawing illustrates a device well suited to the implementation of the method provided for in the invention. The device is mounted in a container 10 in which the banknotes 12 are stored and is activated in the conventional way by means of an electric circuit, not illustrated here, when an attempt is made to steal the container. The new device comprises two identical capsules 14, taking the form of cylinders, and pistons 16 capable of a forward motion therein. The cylinders are relatively short and are so arranged as to be. driven forward under the action of sudden high pressure — in the region of 10 kp or more. Pressure of this magnitude is achieved by the provision in each capsule of an explosive charge 18 acting directly against the piston 16 and set off by a fuse head 20 upon activation as described above. This allows relatively slow combustion of the explosive charge 18, and the piston 16 is thereby driven forward at an even speed inside the relatively short cylinder 14. The dye component, 22 and 24 respectively, inside the cylinder in front of the piston is at the same time forced forwards and outwards through an exit tube 26 connected to the front end of the cylinder. The dye components 22, 24 forced out of each of- the cylinders converge in a mixing chamber 28, where they are mixed. In the embodiment illustrated here the two jets of dye cross each other inside the mixing chamber 28, which makes for more efficient mixing. Efficient mixing is further ensured in that the wall of the mixing chamber is provided with inward projecting, obliquely inclined vanes 30 forcing the dye components to perform a rotary movement as they are propelled towards the nozzle 32, through which run a number of fine channels or holes 34. As the pressure in the cylinders is so great, the dye is projected at such high speed that it is applied to all the banknotes in the container within the very short time available for the operation. OMPI

Claims: [received by t e International Bureau on 07 March 1983 (07.03.83); original claim 1 amended ; original claims 1 to 9 replaced by amended claims 10 to 16] I. (Amended) A method for staining documents (12), e.g. bank-notes, kept in a space protected against theft, such as a container (10), by means of a dye containing finely ground pigments on the attempted theft of the documents, characterized in that the two components (22, 24) selected for their ability to combine to form a quick-drying, two-component dye containing among other substances a resin or other binding agent, and a hardener or similar setting agent, respectively, are stored separately inside the container, and that when the container is tampered with or otherwise subjected to conditions for which it is not intended one or more explosive charges (18) are brought to ignite and by the effect of the pressure exerted thereby also to combine and mix the dye components which together with an agent for the reduction of surface tension are then sprayed under high pressure over the documents. The original claims 2 to 9, inclusive, are cancelled. 10. (Original claim 3) The method of claim 1, character¬ ized in that the composition of the dye is such that once its components (22, 24) have been mixed the dye will dry within a period of 3 minutes. II. (Original claim 4) The method of claims 1 and 10, characterized in that the major portion of the dye components (22, 24) is caused to rotate during mixing. 12. (Original claim 5) A device for the implementation of the method of claim 1 , characterized in that separate capsules • are mounted inside the container for the individual components of the dye and that at least one of the capsules is fitted with an actuator so designed that when the container is tampered with or otherwise subjected to conditions for which it is not intended it will force the component stored in the capsule out under pressure into a mixing chamber having an out¬ let of small holes or channels through which the two-component dye, now ready for use, is expelled. 1.3. (Original claim 6) The device of claim 12, characterized in that each capsule (14) is provided with an actuator (16) and that both actuators are so arranged as to force the components (22, 24) of the dye into the mixing chamber (29) at the same time. 14. (Original claim 7) The device of claim 12 or 13, characterized in that the capsule has the form of a cylinder (14) and the actuator the form of a piston (16) enclosed therein driven forward by an explosive charge (18). 15. (Original claim 8) The device of any of claims 12-14, characterized in that the mixing chamber (28) comprises guides (30) so designed as to ensure efficient mixing by setting up a rotary motion of the said dye components (22, 24). 16. (Original claim 9) The device of claim 15, characterized in that the said guides are comprised of vanes (30) or blades mounted inside the mixing chamber (28) .

Inventors: CEDERGREN STIG, CEDERGREN, STIG
Applicants: CEDERGREN STIG, CEDERGREN, STIG
Application year: 1982
Main classification: E05G1
IPC codes: E05G1