GB2322477A

GB2322477A - Magnetising system for security labels

Info

Publication number: GB2322477A
Application number: GB9703407A
Authority: GB
Inventors: Malcolm Robert Murray Knight; Richard Brian Jotcham; Alan John Tooth
Original assignee: Portals Ltd
Current assignee: Portals Ltd
Priority date: 1997-02-19
Filing date: 1997-02-19
Publication date: 1998-08-26
Anticipated expiration: 2017-02-19
Also published as: GB2322477B; GB9703407D0

Abstract

The invention relates to a magnetising system for applying a verifiable code to a magnetic security element which is embedded in the label of an item. On paying for the item, the label is brushed or scanned past a magnetising head 13 which has a number of teeth 15 separated by gaps 16. The magnetic security element is magnetised in a pattern which is characteristic of the physical arrangement of teeth 15. The pattern on the security element constitutes a verifiable code which can be checked if there is any dispute over whether the item has been paid for. The head may be in the form of a removable insert which can be changed at regular intervals to provide different security patterns. The teeth may have different shapes, for example triangular or oval cross-sections (see figs 5-7).

Description

MAGNETISING SYSTEM FOR SECURITY THREADS AND SECURITY METHOD The invention relates to a magnetising system for security threads and to a security method utilising said magnetising system.

Shoplifting presents a serious problem for most retailers and every year millions of pounds worth of stock is lost due to shoplifting. To try to prevent this, a number of security tags are currently in use.

Some such tags can only be removed by the checkout assistant placing the tag in a device which enables the two parts of the tag to be separated and removed from the tagged item. If the tag is not removed, it activates an alarm as the shoplifter walks out of the door with the item. Whilst the system is simple to operate, the tags are relatively expensive which requires a significant outlay for the retailer, particularly if every item in stock has to be tagged.

In another such system, tags are used which have a core of magnetically soft material surrounded by a different magnetically hard material. Detection of a stolen item involves electromagnetic interrogation at the exit gate of the shop which registers the presence of the soft magnetic material. Deactivation of the tag during payment involves passing the item/tag over a permanent magnet which drives the hard magnetic material in the label to saturation; the remanent field from this hard material then keeps the core of soft magnetic material magnetised and thus does not trigger the interrogating electromagnetic field at the.

exit.

Another system utilises a tag which, if removal is attempted, results in a fluorescent or permanent dye being squirted over the item or the shoplifter.

The disadvantage of this system is the potential damage to the shop's stock.

It has been known for some time to use, as a security feature in valuable security paper, such as banknotes, elongate security elements in the form of threads, strips or ribbons of, for example, plastic film, metal foil, metallised plastics or metal wire in the thickness of security paper to render imitation of documents produced from that paper more difficult.

Patent specification GB-A-1127043 describes security products incorporating a security thread comprising a magnetic material. Such devices allow banknotes and other documents to be authenticated on high speed used note sorting machines and other devices by verification of the presence of the magnetic component. The specification describes the provision of a discontinuous magnetic coating to a thread, which can be detected using the magnetic properties of the magnetic material, which vary according to the discontinuity. However, security paper containing such threads requires a very sophisticated detection system to check for the presence of the thread, the state of which must be permanently the same to ensure that no mistakes occur.

Such systems are very expensive and the value of banknotes is such that such a high cost is justified.

EP-A-0407550 also describes a method of coding security threads for banknotes and the like by providing on the security element a magnetic track which has a machine readable binary code. Again, the magnetic coding is discontinuous and the code is permanent once the banknote has been manufactured.

EP-A-0310707 describes another security document having a magnetically detectable anti-forgery device in the form of a security strip bearing spaced regions of magnetic material which effectively constitute a magnetic bar code. Thus the strip may be preset with a range of information to render forgery difficult.

EP-A-0428779 describes an identification code for security documents and the like comprising a plurality of discrete metallic regions on a security thread separated by spaces, in which the different regions have different magnetic coercivities, which provide a readable code.

EP-A-0463558 relates to an anti-counterfeitable document which is provided with a magnetic code formed by discrete regions of magnetic material on the document itself. The regions of magnetic material are impressed with a magnetic material which is permanently destroyed or removed by mechanical or chemical means, to thereby eliminate the possibility of forgery.

As far as preventing shoplifting is concerned, since most retail goods bear a label giving information such as the price, size etc. of the item, we propose that a security element could be incorporated therein to provide a security feature.

However, the purpose of using such a security feature is not, as in the previous examples, to enable a check for authenticity to be made, but to provide a system which allowed a code or message to be added to such a security element or cancelled depending on whether an article had been purchased or not, it is an object of the present invention to provide a method and apparatus to enable a verifiable code to be applied to a magnetic security element in a label or other security document, which could be attached to an item for purchase. If a shopper was accused of shoplifting on his/her way out of a shop, examination of the label with appropriate means would determine whether the item had passed through the checkout station and been paid for by checking to see that the appropriate code had been applied to the security element.

The invention therefore relates to a magnetising system for applying a verifiable code to a magnetic security element comprising a magnet having a magnetising head, said head comprising a series of spaced apart teeth along its length, the pattern of the teeth defining the said code.

The base magnet may be an electro-magnet or a permanent magnet and there may be one or a plurality of magnets.

The head is preferably of a soft magnetic material. Alternatively it may be of a hard magnetic material and is located within the magnetic field of the magnet.

The teeth of the head are regularly or irregularly spaced. In a preferred embodiment of the invention the dimensions of each tooth are the same.

Alternatively, the width of the teeth are not the same.

The teeth preferably are parallel-sided.

Preferably the head comprises a removable insert which carries the teeth.

The invention also provides a security system comprising a magnetising system as described above, a plurality of labels or other documents having an elongate magnetisable security element and a detection system to verify the code applied to the magnetic security element by means of said magnetising system.

The detection system preferably enables the code to be seen as a magnetic pattern.

The detection system preferably comprises one or more inductive or magneto-resistive heads which enables the code to be verified in the form of a time dependent change of signal corresponding to the movement of the magnetised security element relative to the magnetic head.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a pictorial representation of a magnetising system according to the present invention; Fig. 2 is a sample label for use with the magnetiser of Fig. 1; Fig. 3 is a plan view of magnetic viewer for verifying the encoded labels of Fig. 2; and Figs. 4 to 7 are pictorial representations of alternative head configurations for the system of Fig.

1.

Referring to Fig. 1 there is shown a magnetising system comprising a housing 11 containing a magnet 12 having a magnetising head 13. The head 13 may be an extension of the magnet 12 itself or a separate component located with the magnetic field of the magnet 12. In the latter embodiment, the magnetising head 13 is of a hard or soft magnetic material. The magnet 12 may comprise two arms of a single magnet or two separate magnets, the magnet or magnets being permanent or electro-magnets.

The head 13 has a comb-like profile 14 consistingof a number of teeth 15 with gaps 16 therebetween.

The gaps 16 may be vacant or filled with non-magnetic material. The profile 14 of the head 13 is exposed so that a label 20 can be brought into contact therewith as described below. Alternatively the head 13 may be an extension of the magnet 12 itself.

A security document, such as a label 20, is typically made of paper, card or a polymeric material.

In the preferred embodiment, an elongate security element 21 is embedded within the material of the label 20. The security element 21 may be in the form of a thread, strip or film of a polymeric material supporting one or more layers of magnetic material or, less preferably, comprises a strip of magnetic metal.

Typical threads for use in such labels are in the width range of 0.5mm to 4mm although preferably in the range of 1.2mm to 1.6mm. Threads or stripes of magnetic material outside this range may also be used.

Although the security element 21 is preferably embedded in the label 20, it may be exposed at intervals along its length in windows.

In a further embodiment of the present invention the security element 21 may comprise a line of magnetic material or ink coated onto the label 20 or onto a film, as a stripe, which is then applied to the paper base. Alternatively, the magnetic material or ink may be in the form of a patch, rather than a strip or stripe.

The security element 21 comprises a continuous layer of a magnetic material such as gamma ferric oxide of coercivity 29.8kA/m (375 Oersted).

Alternatively other magnetic materials may be used including modified ferric oxide of different coercivity magnetite, chromium dioxide, barium ferrite or the like. The security element 21 may also comprise a magnetic metal in either a continuous or patterned form, as is described in our published patent specification WO 96/04143. The selection of material for the security element, and the field strength of the magnetising system are chosen such that a definable pattern may be determined on the subsequent viewing/detection system.

On receiving payment from a customer for an item bearing a security label 20, the checkout assistant would brush the label 20 past the magnetising head 13 in the direction of arrow A with either of the edges 22 or 23 (which are parallel to the security element 21) leading. The magnetic security element 21 is thereby magnetised in a pattern which is characteristic of the physical arrangement of the teeth 15 in the head 13. This pattern constitutes a verifiable code which can be checked using a known magnetic recording tape viewer 25, such as that described in U.S. Patent No. 3013206. The viewer comprises a case 26 having a window 27 on one side and enclosing a fluid incorporating coloured magnetic particles. To use the viewer 25, the flat base is placed over the security label 20 and the particles in the dispersion align themselves up with a magnetic field generated by the magnetised security element 21 in a manner which is visually detectable, thus revealing the pattern of the field.

The comb-like profile 14 described produces a characteristic wave pattern where the wavelength varies according to the spacing and dimensions of the teeth 15 of the head 13 along its length. If the security element 21 is an elongate continuous thread and is magnetised in a continuous field, an image of the magnetised element 21 appears as a dark or coloured straight line in the window 27 of the viewer 25. Where a continuous element 21 has been magnetised with the head 13 containing the pattern of teeth 15 as shown in Fig. 1, the pattern 28 observed in the viewer 25 is discontinuous as shown in Fig. 3, the shaded areas corresponding to the magnetised areas of the element 21. Thus if there is any dispute over whether a particular item has been paid for, the existence and pattern of the code on the element 21 can easily and quickly be verified and if it is there, confirmation obtained that the item had been legitimately purchased.

The profile 14 of the head 13 can be varied and may have regular or irregular dimensions to both the width of the teeth 15 and the teeth spacing 16, an example of which is shown in Fig. 4. It is thus unlikely that an observer will confuse the true pattern derived from magnetisation of a magnetic security element 21 with the magnetising system 10 with a spurious magnetic field owing to e.g. a magnetised piece of metal on the viewing table which could be, for example, a supermarket checkout desk.

As an alternative to the viewer 25, a more sophisticated detection system could be used to determine the code magnetisation produced by the magnetising system 10; such a system may make use of an array of inductive or magneto-resistive heads.

Alternatively, the label 20 and the element 21 are passed in a longitudinal direction under a single inductive or magneto-resistive head; in such a system, the pattern would emerge as a time-dependent change of signal corresponding to the movement of the magnetised element 21 under the magnetic head. Where magnetoresistive heads are used, the label may be placed over the head, or the head applied over the label, and the corresponding magnetic pattern determined without relative movement between head and label.

To further increase the security of such a method each shop and/or each individual checkout point could be equipped with a characteristic profiled head 13.

The head 13, if necessary or desirable, could be changed at regular intervals to prevent counterfeiters taking in pre-coded labels, such as genuine labels from an earlier sale, to attach to articles in replacement of the correct label. To facilitate such changes, the head 13 may incorporate a recess to receive a removable insert carrying the profile 14.

Thus the basic magnetising system 10 could be built into a checkout counter and a number of different inserts with different profiles could be safely stored to be used when required.

In another embodiment of the invention, the security element 21 may be magnetised by vertical application to the head 13 instead of transverse swiping. This is more effective with wider security elements, of say 4.Omm, and allows the use of a wider variety of patterns of teeth 15. In this embodiment, it is no longer necessary to use parallel sided teeth, instead the teeth 15 may have triangular, circular or oval cross-sections or a combination of teeth, some of which are square and/or rectangular and some of which are triangular and/or circular as shown in Figs. 5 to 7.

Although the invention has only been described with reference to anti-shoplifting labels, it clearly has a number of other applications for applying a verifiable code in the form of a pattern to a magnetic security element e.g. for the authentication of currency or other security documents.

Claims

CLAIMS:

1. A magnetising system for applying a verifiable code to a magnetic security element comprising a magnet having a magnetising head, said head comprising a series of spaced apart teeth along its length, the pattern of the teeth defining the said code.

2. A magnetising system as claimed in claim 1 in which the magnet is an electro-magnet.

3. A magnetising system as claimed in claim 1 in which the magnet is a permanent magnet.

4. A magnetising system as claimed in any one of the preceding claims in which there are a plurality of magnets.

5. A magnetising system as claimed in any one of the preceding claims in which the head is of a soft magnetic material and is located within the magnetic field of the magnet.

6. A magnetising system as claimed in any one of claims 1 to 4 in which the head is of a hard magnetic material and is located within the magnetic field of the magnet.

7. A magnetising system as claimed in any one of the preceding claims in which the teeth are regularly spaced.

8. A magnetising system as claimed in any one of claims 1 to 6 in which the teeth are irregularly spaced.

9. A magnetising system as claimed in any one of the preceding claims in which the dimensions of each tooth are the same.

10. A magnetising system as claimed in any one of claims 1 to 8 in which the widths of the teeth are not the same.

11. A magnetising system as claimed in any one of the preceding claims in which the teeth are parallelsided.

12. A magnetising system as claimed in any one of claims 1 to 10 wherein the teeth are circular, oval or triangular in cross-section.

13. A magnetising system as claimed in any one of the preceding claims in which the head comprises a removable insert which carries the teeth.

14. A security system comprising a magnetising system as claimed in any one of the preceding claims a plurality of labels or other documents having therein or thereon a region of magnetisable material and a detection system to verify the code applied to the magnetisable region by means of said magnetising system.

15. A security system as claimed in claim 14 in which the detection system enables the code to be seen as a magnetic pattern.

16. A security system as claimed in claim 14 in which the detection system comprises one or more inductive or magneto-resistive heads which enables the code on the magnetised strip to be verified.

17. A magnetising system substantially as hereinbefore described with reference to and as shown in Fig. 1 of the accompanying drawings.

18. A security system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS: 1. A magnetising system for applying a verifiable code to a magnetic security element comprising a magnet having a magnetising head, said head comprising a series of spaced apart teeth along its length, the pattern of the teeth defining the said code.

14. A security system comprising a magnetising system as claimed in any one of the preceding claims, a plurality of labels or other documents having therein or thereon a region of magnetisable material and a detection system to verify the code applied to the magnetisable region by means of said magnetising system.

16. A security system as claimed in claim 14 in which the detection system comprises one or more inductive or magneto-resistive heads which enables the code on the magnetised region to be verified.