EP0756255A1 - Deactivatable security tag and method and device for its manufacturing - Google Patents

Abstract

The security strip is provided by a soft magnetic strip (2) of given length, subjected to an AC field for providing a characteristic signal upon stimulation, with spaced strips (3) of a hard or semi-hard magnetic material along the soft magnetic strip which block the characteristic signal upon saturation. The hard or semi-hard magnetic strips have periodic sections (4b) of given length (b) with a remanent magnetisation component parallel to the longitudinal direction which is less than the corresponding remanent magnetisation component for the remaining sections (4a) of the hard or semi-hard magnetic strip.

Description

The invention relates to a deactivatable security strip, in particular for article security in department stores, which consists of a soft magnetic strip of a predetermined length, which is stimulated to emit a characteristic signal when an alternating magnetic field is applied, and sections of a defined length of a semi-hard or hard magnetic material with respect to the soft magnetic strip are arranged such that they suppress the characteristic signal of the soft magnetic strip in the saturated state. Furthermore, the invention relates to a method and an apparatus for producing such a security strip.

Soft magnetic, activatable material (e.g. Permalloy) is characterized by a high permeability and a low coercive force and is excited in the monitoring zone of the entrance / exit area of a department store by an alternating magnetic field to emit a characteristic signal. This signal is subsequently detected by a detector device which is sensitive in the frequency range of the signal and as an identification signal for an unauthorized one Evaluated goods passing through the surveillance zone; an alarm is triggered.
Of course, the detector device should no longer respond as soon as the goods have been properly paid for.
The semi-hard or hard magnetic strip-shaped sections serve this purpose. Semi-hard or hard magnetic material has the opposite properties of soft magnetic material: it is characterized by a low permeability and a high coercive force.
Due to the high coercive force, the deactivator material in the non-deactivated state is not influenced by the alternating magnetic field in the monitoring zone. However, as soon as the deactivator material is driven into saturation by a correspondingly high magnetic field - which occurs after the goods have been properly paid for - its magnetization prevents a reaction of the soft magnetic material to the alternating magnetic field in the monitoring zone.

Deactivable security elements are used in large quantities. Since each security element is usually only used once for item security, special attention is paid to cost-effective production.
DE 42 23 394 A1 has already disclosed a method for producing security labels, which comprises the following production steps: a hard-magnetic metal strip is glued onto a non-metallic tape and then an elastic carrier film is glued onto the metal strip. The carrier film is so thick and flexible that the deformation of the metal strip by a rotating punching knife is sufficient to separate the metal strip into individual sections. The separated sections of the metal strip and the non-metallic strip are pulled off the carrier film, and a soft magnetic strip is then applied to the remaining parts of the metal strip. In order to produce a finished label tape, as is generally customary, label paper is glued onto one side of the tape and a carrier tape is glued to the other side.

This method, which has become known, is undoubtedly ideally suited for the provision of large numbers of securing elements. What is less satisfactory, however, is the relatively high outlay which must be carried out in the production and application of the semi-hard or hard magnetic sections on the soft magnetic strips.

The invention is based on the object of proposing a cost-effective and easy-to-implement deactivatable security strip, as well as a method and a device which allow inexpensive and simple manufacture of a deactivatable security strip.

parallel zur Längsrichtung (:= Vorzugsrichtung) des halbhart- oder hartmagnetischen Streifens geringer ist als die Komponente der remanenten Magnetisierung M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

in den dazwischenliegenden, unbehandelten Abschnitten. Mathematisch läßt sich dieser Sachverhalt durch die Ungleichung: M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

>> M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

bzw. M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

/M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

>> 1 beschreiben.The object is achieved with regard to the security strip in that the semi-hard or hard magnetic strip is treated periodically at a predetermined distance a from successive sections of a predetermined length b by supplying energy in such a way that in the treated sections the component of the remanent magnetization M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

parallel to the longitudinal direction (: = preferred direction) of the semi-hard or hard magnetic strip is less than the component of the remanent magnetization M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

in the intermediate, untreated sections. This fact can be mathematically explained by the inequality: M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

>> M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

or M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

/ M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

>> 1 describe.

According to an advantageous embodiment of the security strip according to the invention it is provided that the saturation magnetization M _s in the sections parallel to the preferred direction of the semi-hard or hard magnetic strip approaches zero.

quer zur Vorzugsrichtung des halbhart- oder hartmagnetischen Streifens induziert ist.An alternative embodiment, which can certainly be used in connection with the first-mentioned embodiment, provides that a uniaxial anisotropy K $\genfrac{}{}{0ex}{}{\text{1}}{\text{u}}$

is induced transversely to the preferred direction of the semi-hard or hard magnetic strip.

in Vorzugsrichtung des halbhart- oder hartmagnetischen Streifens aufweist, die geringer ist als die Komponente der remanenten Magnetisierung M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

in den dazwischenliegenden, unbehandelten Abschnitten.The object is achieved with respect to the method for producing a security strip according to the invention in that energy is supplied periodically at a distance a from one another to sections b of the length b of the semi-hard or hard magnetic strip, the energy supply being dimensioned such that the strip in the treated sections has a Component of the remanent magnetization M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

in the preferred direction of the semi-hard or hard magnetic strip, which is less than the component of the remanent magnetization M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

in the intermediate, untreated sections.

According to an advantageous development of the method according to the invention, it is provided that the sections which follow one another periodically at a predetermined distance are electrically heated by supplying current. This embodiment of the method is extremely simple to implement and, moreover, allows a high working speed.

An inexpensive and reliable design of the method according to the invention suggests that the temperature in the treated sections is monitored and that the circuit is interrupted as soon as a predetermined temperature is reached in the treated sections.
In addition to the fact that a contactless temperature measurement can be implemented very easily and with high accuracy using a radiation detector, the temperature measurement is of course also ideally suited as an indicator for indicating when the originally semi-hard or hard magnetic material has changed its physical properties according to the invention.

The treatment process is ended in a simple manner by interrupting the circuit. This can be achieved in that the strip is lifted off the contact heads and / or in that the control device switches off the power source.

According to a development of the method according to the invention, it is particularly advantageous that the strip with the semi-hard or hard magnetic sections and the treated sections is subsequently applied directly to the soft magnetic strip material. Due to the direct bonding of semi-hard or hard magnetic and soft magnetic tape material, very thin security strips can be manufactured, which is of great importance especially in the case of so-called source integration, when the security strips are implemented in the goods to be secured.

In addition to the electrical energy supply, according to an advantageous development of the method according to the invention it is also possible for the sections of length b to be supplied with laser energy.

, angelegt wird, wobei die Richtung des Magnetfeldes näherungsweise senkrecht zur Vorzugsrichtung des halbhart- oder hartmagnetischen Streifens liegt. Die Anisotropiefeldstärke H_k ist die Feldstärke, die erforderlich ist, um das Material quer zur Vorzugsrichtung zu sättigen.It has proven to be particularly advantageous if, during the energy supply to the sections of length b, a magnetic field with at least the anisotropy field strength H _k , with ${\text{H}}_{\text{k}}{\text{= <figure-callout id="0" label="2K u" filenames="imgf0002.png,imgf0004.png" state="{{state}}">2K </figure-callout>}}_{\text{u}}^{}{\text{/ M}}_{\text{s}}^{\text{0}}$

, is applied, the direction of the magnetic field being approximately perpendicular to the preferred direction of the semi-hard or hard magnetic strip. The anisotropy field strength H _k is the field strength that is required to saturate the material transversely to the preferred direction.

The same effect can also be achieved in that the sections of length b are subjected to a mechanical tension (tension or compression) during the energy supply.
Again, the tension is dimensioned such that a tension-induced anisotropy is generated in the treated sections perpendicular to the preferred direction of the semi-hard or hard magnetic strip.

With regard to the device, the object is achieved in that a plurality of treatment stations arranged at a distance a from one another are provided, which correspond to the sections of length b of the semi-hard or hard magnetic strip material Supply energy, and that at least one control device is provided which controls the supply of energy into the treated sections and the feed of the strip material.

The treatment stations are advantageously in each case two contact heads arranged at a distance b, which are connected to a power source, the portion to be treated in each case forming part of the circuit.

According to an advantageous embodiment of the device according to the invention, on the side of the strip material that lies opposite the contact heads, pressing elements corresponding to the contact heads are provided, which press the strip material against the contact heads during the treatment period.

As already mentioned at the previous point, a radiation detector (photodetector) operating as a temperature sensor is provided, which detects the temperature of the sections without contact.

According to an advantageous development of the device according to the invention, a pair of rollers is provided which is driven intermittently and thereby moves the strip material between the contact heads and the pressing elements.

• Fig. 1: eine perspektivische Darstellung eines erfindungsgemäßen, deaktivierbaren Sicherungsstreifens,
• Fig. 2a: eine perspektivische Darstellung eines üblichen halbhart- oder hartmagnetischen Streifens,
• Fig. 2b: eine typische Hysteresekurve des in Fig. 2a dargestellten halbhart- oder hartmagnetischen Streifens,
• Fig. 3a: eine perspektivische Ansicht eines erfindungsgemäßen Sicherungselementes gemäß einer ersten Ausführungsform,
• Fig. 3b: eine Darstellung einer typischen Hysteresekurve entlang der Vorzugsrichtung der behandelten Abschnitte des in Fig. 3a darstellten Streifens,
• Fig. 3c: eine schematische Darstellung des Verlaufs des Streufeldes H_s bei dem in Fig. 3a dargestellten Streifen (Längsschnitt durch den Streifen 1),
• Fig. 4a: eine perspektivische Ansicht eines erfindungsgemäßen Sicherungselementes gemäß einer zweiten Ausführungsform,
• Fig. 4b: eine Darstellung einer typischen Hysteresekurve entlang der Vorzugsrichtung der behandelten Abschnitte des in Fig. 4a darstellten Streifens,
• Fig. 4c: eine schematische Darstellung des Verlaufs des Streufeldes H_s bei dem in Fig. 4a dargestellten Streifen (Längsschnitt durch den Streifen),
• Fig. 5: eine schematische Darstellung eines Fertigungsprozesses für Sicherungsstreifen, in den die erfindungsgemäße Vorrichtung bzw. das erfindungsgemäße Verfahren integriert ist,
• Fig. 6: eine Darstellung einer Ausführungsform der erfindungsgemäßen Vorrichtung und
• Fig. 7: ein Flußdiagramm zur Ansteuerung der Steuereinrichtung 19 für die in Fig. 5 gezeigte Vorrichtung.

The invention is explained in more detail with reference to the following figures. It shows:

• 1: a perspective view of a deactivatable security strip according to the invention,
• 2a: a perspective view of a conventional semi-hard or hard magnetic strip,
• 2b: a typical hysteresis curve of the semi-hard or hard magnetic strip shown in FIG. 2a,
• 3a: a perspective view of a securing element according to the invention according to a first embodiment,
• 3b: a representation of a typical hysteresis curve along the preferred direction of the treated sections of the strip shown in FIG. 3a,
• 3c: a schematic representation of the course of the stray field H _s in the strip shown in FIG. 3a (longitudinal section through the strip 1),
• 4a: a perspective view of a securing element according to the invention according to a second embodiment,
• 4b: a representation of a typical hysteresis curve along the preferred direction of the treated sections of the strip shown in FIG. 4a,
• 4c: a schematic representation of the course of the stray field H _s in the strip shown in FIG. 4a (longitudinal section through the strip),
• 5: a schematic representation of a production process for security strips, in which the device according to the invention and the method according to the invention are integrated,
• 6 shows a representation of an embodiment of the device according to the invention and
• FIG. 7: a flowchart for controlling the control device 19 for the device shown in FIG. 5.

A perspective view of a deactivatable security strip 1 can be seen in FIG. 1. The deactivatable security strip 1 consists of a soft magnetic strip 2, on which a semi-hard or hard magnetic strip 3 is laminated. The structure and the properties of the semi-hard or hard magnetic strip 3 have been changed periodically at intervals a successive sections 4b by the supply of energy. According to the invention, the supply of energy has caused the original physical properties of the semi-hard or hard magnetic strip to have changed in the treated sections 4b. Thus, the original, physical properties of the semi-hard or hard magnetic strip 3 can only be found in the untreated sections 4a.

zu sehen. Als Folge des Herstellungsprozesses zeigt der Streifen 3 eine remanente Magnetisierung M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

und eine Anisotropie K $\genfrac{}{}{0ex}{}{\text{0}}{\text{u}}$

in einer Vorzugsrichtung. Im dargestellten Falle liegt die Vorzugsrichtung in x-Richtung.2a shows a perspective illustration of a conventional semi-hard or hard magnetic strip 3 with the remanent magnetization M. $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

to see. As a result of the manufacturing process, the strip 3 shows a remanent magnetization M. $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

and an anisotropy K $\genfrac{}{}{0ex}{}{\text{0}}{\text{u}}$

in a preferred direction. In the case shown, the preferred direction is in the x direction.

FIG. 2 b shows the hysteresis curve of the semi-hard or hard magnetic strip 3 shown in FIG. 2 a, that is to say the change in the magnetization M as a function of the field strength H of the external magnetic field. SEMIVAC, which is sold by Vacuumschmelze, is an example of a semi-hard magnetic material.

3a shows a perspective view of a first embodiment of the semi-hard or hard magnetic strip 3 according to the invention. The semi-hard or hard magnetic strip 3 shows sections 4b of length b which are arranged at a distance a from one another. The sections 4b have been subjected to a heat treatment and have changed their magnetic properties as a result of this heat treatment.

>> M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

, M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

/M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

>> 1. In dieser Ausführungsform hat sich also lediglich die Magnetisierung M in den behandelten Abschnitten 4b geändert. Sie weisen jedoch weiterhin ebenso wie die unbehandelten Abschnitte 4a eine einachsige Anisotropie K $\genfrac{}{}{0ex}{}{\text{0}}{\text{u}}$

parallel zur Vorzugsrichtung (hier: x-Richtung) auf.As can be easily seen from a comparison between the two figures FIGS. 2b and 3b, the remanent magnetization M _{r is} opposite in the treated sections 4b the corresponding sections in the untreated state have become smaller. The desired result, striven for and realized by the invention, is achieved if - mathematically expressed - the following condition is fulfilled: M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

>> M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

, M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

/ M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

>> 1. In this embodiment, only the magnetization M in the treated sections 4b has changed. However, just like the untreated sections 4a, they still have a uniaxial anisotropy K $\genfrac{}{}{0ex}{}{\text{0}}{\text{u}}$

parallel to the preferred direction (here: x direction).

bzw. M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

in den behandelten Abschnitten 4b bzw. den unbehandelten Abschnitten 4a treten Streufelder auf. Im Idealfall zeigen die unbehandelten Abschnitte 4a ein physikalisches Verhalten, als sei zwischen den behandelten Abschnitten 4b kein Material (bzw. Luft) vorhanden. Es wird also derselbe Effekt erreicht, den auch die bislang bekanntgewordenen Sicherungsstreifen mit beabstandeten Deaktivatorabschnitten zeigen.3c shows a longitudinal section through the strip 3 according to the invention shown in FIG. 3a. In particular, the magnetic field profile can be seen from this figure. Due to the different remanent magnetizations M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

or M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

Stray fields occur in the treated sections 4b and the untreated sections 4a. In the ideal case, the untreated sections 4a show a physical behavior as if there was no material (or air) between the treated sections 4b. The same effect is thus achieved, which the previously known security strips with spaced deactivator sections also show.

quer zur Vorzugsrichtung (hier: x-Richtung) erzeugt. In den unbehandelten Abschnitten 4a zeigt sich weiterhin die ursprüngliche Anisotropie K $\genfrac{}{}{0ex}{}{\text{0}}{\text{u}}$

des halbhart- oder hartmagnetischen Streifens 3. Erreichen läßt sich dies durch Anlegen eines Magnetfeldes H während der Energiezufuhr zu den Abschnitten 4b. Das angelegte Magnetfeld H sollte zumindest die Anisotropiefeldstärke ${\text{H}}_{\text{k}}{\text{= 2K}}_{\text{u}}^{\text{0}}{\text{/,M}}_{\text{r}}^{\text{0}}$

aufweisen. Die Anisotropiefeldstärke H_k ist -wie bereits erwähnt- die Feldstärke, die notwendig ist, um in den behandelten Abschnitten 4b die Anisotropie in Vorzugsrichtung zu überwinden und den behandelten Abschnitten 4b eine einachsige Anisotropie K $\genfrac{}{}{0ex}{}{\text{1}}{\text{u}}$

quer zur Vorzugsrichtung des halbhart- oder hartmagnetischen Streifens 3 aufzuprägen.4a shows a second embodiment of the strip 3 according to the invention in a perspective view. While only the remanent magnetization M _{r was} influenced as a result of the supply of energy to the sections 4b in the embodiment shown in FIGS. 3a, 3b and 3c, here a uniaxial anisotropy K also occurs in the treated sections 4b $\genfrac{}{}{0ex}{}{\text{1}}{\text{u}}$

generated perpendicular to the preferred direction (here: x direction). The original anisotropy K continues to be shown in the untreated sections 4a $\genfrac{}{}{0ex}{}{\text{0}}{\text{u}}$

of the semi-hard or hard magnetic strip 3. This can be achieved by applying a magnetic field H during the energy supply to the sections 4b. The applied magnetic field H should be at least the anisotropy field strength ${\text{H}}_{\text{k}}{\text{= <figure-callout id="0" label="2K u" filenames="imgf0002.png,imgf0004.png" state="{{state}}">2K </figure-callout>}}_{\text{u}}^{}{\text{/, <figure-callout id="0" label="M r" filenames="imgf0002.png,imgf0004.png" state="{{state}}">M </figure-callout>}}_{\text{r}}^{}$

exhibit. As already mentioned, the anisotropy field strength H _k is the field strength that is necessary in order to overcome the anisotropy in the preferred direction in the treated sections 4b and the treated sections 4b a uniaxial anisotropy K $\genfrac{}{}{0ex}{}{\text{1}}{\text{u}}$

to be embossed transversely to the preferred direction of the semi-hard or hard magnetic strip 3.

As can be seen from FIGS. 4b and 4c, the effect of this embodiment of the security strip 1 according to the invention with respect to the remanence (component of the remanent magnetization) in the preferred direction or the course of the stray field H _{s is} equivalent to that in the figures 3a, 3b and 3c shown embodiment.

5 shows a schematic representation of a manufacturing process for a security strip. The device according to the invention and the method according to the invention are integrated into this manufacturing process.
The soft magnetic strip material 2 is unwound from a roll 5 and stored in a buffer device 7. The soft magnetic strip material 2 is guided into the device 10 via a deflection roller 9. In this device 10, one side of the soft magnetic strip material 2 is coated with adhesive.

The semi-hard or hard magnetic strip material 3 is also unwound from a roll 6 and stored in a buffer device 8. In the device 11 according to the invention, the semi-hard or hard magnetic tape material 3 is divided into individual sections 4 and then glued onto the soft magnetic tape material 2 at a distance b. The security strip 1 is dried in the dryer 12; Finally, the dried security strip 1 is wound onto the roll 14, a buffer device 13 being interposed, which compensates for differences in the tension acting on the security strip 1.

6 shows an embodiment of the device 11 according to the invention. The semi-hard or hard magnetic strip material 3 is gradually increased by means of the pair of rollers 19 passed between the contact heads 15, 16 and the pressing elements 22 opposite them. The right contact head 16 of a pair or the corresponding pressing element 22 is arranged at a distance a from the left contact head 15 or the corresponding pressing element 23 of the subsequent pair.

When the desired position of the strip material 3 is reached, the control device 20 moves the pressure elements 22 and the contact heads 15, 16 together until an intimate contact is established between the contact heads 15, 16 and the strip material.
The power supplies 17 are then activated. The current flowing between the contact heads 15, 16 heats the sections 4b of the strip material 3 until its originally semi-hard or hard magnetic properties have changed according to the invention. Since a certain temperature must exist in sections 4b for this physical change process, reaching a predetermined temperature is used as an indicator that the conversion process has been completed. The temperature in the treated sections 4b is advantageously determined in a contactless manner by means of radiation sensors 18 (photosensors). The temperature values are forwarded to the control device.

entspricht und die zuvorbeschriebenen Verfahrensschritte werden wiederholt. Die Information über die Winkelstellung wird von dem Winkelgeber 21 geliefert, der an der Achse einer der beiden Walzen 19a, 19b angebracht ist. Vorzugsweise ist die Drehbewegung der beiden Walzen 19a, 19b des Walzenpaares 19 über in der Zeichnung nicht gesondert dargestellte Zahnräder gekoppelt. Das Bandmaterial 3 mit den halbhart- oder hartmagnetischen Abschnitten 4a und den behandelten Abschnitten 4b wird anschließend direkt auf das weichmagnetische Bandmaterial 2 laminiert, das über die Walze 19b zugeführt wird.As soon as the predetermined temperature has been reached, the control device 20 causes the contact heads 15, 16 and pressing elements 22 and 23 to move apart. The control device 20 then rotates the pair of rollers 19 further by an angle α that corresponds to the distance $\text{n · (a + b)}$

corresponds and the previously described process steps are repeated. The information about the angular position is supplied by the angle transmitter 21, which is attached to the axis of one of the two rollers 19a, 19b. The rotary movement of the two rollers 19a, 19b of the pair of rollers 19 is preferably coupled via gearwheels which are not shown separately in the drawing. The strip material 3 with the semi-hard or hard magnetic sections 4a and the treated sections 4b is then directly on the Laminated soft magnetic tape material 2, which is fed via the roller 19b.

weiterbewegt; diese Strecke entspricht einer Drehung der Walzen 19a, 19b des Walzenpaares 19 um den Winkel α. Sobald die Drehung um den Winkel α ausgeführt ist, springt das Programm auf den Punkt 25 zurück und der Zyklus wiederholt sich.FIG. 7 shows a flowchart for controlling the control device 19 for the device shown in FIG. 5. After starting the program at 24, the contact heads 15, 16 and the corresponding pressing elements 22, 23 are moved together according to the program points 25 and 26 until an intimate contact is made between contact heads 15, 16 and strip material 3 - which after covering the path x Case is. At 27 and 28, the current sources 17 are activated until the predetermined target temperature Tsoll is reached in the treated sections 4b. The contact heads 15, 16 and the pressing elements 22, 23 are then moved apart by the distance x at 29 and 30. Now the strip material 3 is moved according to the program points 31 and 32 $\text{3 • (a + b)}$

moved on; this distance corresponds to a rotation of the rollers 19a, 19b of the pair of rollers 19 by the angle α. As soon as the rotation through the angle α has been carried out, the program jumps back to point 25 and the cycle repeats.

Reference list

1

deactivatable security strip

2nd

soft magnetic stripe

3rd

semi-hard or hard magnetic stripe

4a

semi-hard or hard magnetic section

4b

treated section

5

role

6

role

7

Buffer device

8th

Buffer device

9

Deflection roller

10th

Adhesive feeder

11

Device for the production of security strips

12th

dryer

13

Buffer device

14

role

15

Contact head

16

Contact head

17th

Power supply

18th

Radiation sensor

19th

Pair of rollers

19a

roller

19b

roller

20th

Control device

21

Angle encoder

22

Pressing element

23

Pressing element

Claims (14)

Deactivatable security strips, in particular for article security in department stores, which consist of a soft magnetic strip of a given length, which is stimulated to emit a characteristic signal when an alternating magnetic field is applied, and sections of a defined length of a semi-hard or hard magnetic material that relate to the soft magnetic strip are arranged in such a way that they suppress the characteristic signal of the soft magnetic strip when saturated,
characterized,
that the semi-hard or hard magnetic strip (3) is treated periodically at a predetermined distance (a) successive sections (4b) of a given length (b) by supplying energy in such a way that in the treated sections (4b) the component of the remanent magnetization ( M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

) parallel to the longitudinal direction (: = preferred direction) of the semi-hard or hard magnetic strip (3) is less than the component of the remanent magnetization (M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

) in the intermediate, untreated sections (4a). Security strip according to claim 1,
characterized,
that the saturation magnetization (M _s ) in the treated sections (4b) parallel to the preferred direction of the semi-hard or hard magnetic strip (3) goes to zero. Security strip according to claim 1,
characterized,
that in the treated sections (4b) uniaxial anisotropy (K $\genfrac{}{}{0ex}{}{\text{1}}{\text{u}}$

) is induced transversely to the preferred direction of the semi-hard or hard magnetic strip (3). Process for the production of deactivatable security strips, in particular for article security in department stores, wherein a deactivatable security strip consists of a soft magnetic strip which carries sections of a certain length from a semi-hard or hard magnetic material at defined intervals,
characterized,
that periodically at a distance (a) successive sections (4b) of the length (b) of the semi-hard or hard magnetic strip (3) energy is supplied, the energy supply being dimensioned such that the strip (3) in the treated sections (4b ) a component of the remanent magnetization (M $\genfrac{}{}{0ex}{}{\text{1}}{\text{r}}$

) in the preferred direction of the semi-hard or hard magnetic strip (3), which is less than the component of the remanent magnetization (M $\genfrac{}{}{0ex}{}{\text{0}}{\text{r}}$

) in the intermediate, untreated sections (4a). Method according to claim 4,
characterized,
that the periodically successive sections (4b) at the predetermined distance (a) are electrically heated by supplying current. Method according to claim 4 or 5,
characterized,
that the power supply to the periodically (a) successive sections (4b) of the semi-hard or hard magnetic strip (3) is cut off as soon as a predetermined temperature is reached in the treated sections (4b). Method according to claim 4,
characterized,
that the sections (4b) laser energy is supplied. Method according to claim 4, 5, 6 or 7,
characterized,
that to the sections (4b) during the supply of energy with a magnetic field with at least the anisotropy field strength (H _k ) ${\text{H}}_{\text{k}}{\text{= 2K}}_{\text{u}}^{\text{0}}{\text{/ M}}_{\text{s}}^{\text{0}}$

is applied, the direction of the magnetic field being approximately perpendicular to the preferred direction of the semi-hard or hard magnetic strip (3). Method according to claim 4, 5, 6 or 7,
characterized,
that a mechanical tension is applied in the sections (4b) during the supply of energy, which is dimensioned such that the tension-induced anisotropy is perpendicular to the preferred direction of the originally untreated, semi-hard or hard magnetic strip (3). Device for producing a deactivatable security strip, in particular for article security in department stores, the deactivatable security strip consisting of a soft magnetic strip which carries sections of a certain length at defined intervals from a semi-hard or hard magnetic material,
characterized,
that a plurality of treatment stations (15, 16, 17) arranged at a distance (a) from one another are provided, which supply energy to the sections (4b) of the length (b) of the semi-hard or hard magnetic strip (3), and that at least one control device ( 20) is provided, which controls the energy supply to the sections (4b) of the semi-hard or hard magnetic strip (3). Apparatus according to claim 10,
characterized,
that it is at a treatment station (15, 16, 17) each two spaced (b) contact heads (15, 16) which are connected to a power source (17), the circuit by contact with the semi-hard or hard magnetic strip (3) is closed. Device according to claim 10 or 11,
characterized,
that pressure elements 22, 23 are provided which face the contact heads 15, 16. Apparatus according to claim 10,
characterized,
that a radiation detector (18) operating as a temperature sensor is provided, which detects the temperature of the sections (4b). Device according to claims 11 and 12,
characterized,
that a pair of rollers (19) consisting of rollers (19a, 19b) is provided which is driven intermittently and thereby moves the strip (3) between the contact heads (15, 16) and the pressing elements (22, 23).

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