METHOD AND APPARATUS FOR CHECKING VALUE DOCUMENTS

• US 20130082105A1
• Filed: 05/18/2011
• Published: 04/04/2013
• Est. Priority Date: 06/09/2010
• Status: Active Grant

• Current Assignee: Giesecke & Devrient (Giesecke & Devrient GmbH)
• Original Assignee: Jurgen Schutzmann
• Inventors: Paul, Elisabeth, Schtzmann, Jrgen
• Granted Patent: US 8,910,869 B2
• Time in Patent Office: Days
• US Class Current: 235/450
• CPC Class Codes: G06K 5/00 Methods or arrangements for verifying the correctness of markings on a record carrier; Column detection devices
• CPC Class Codes: G06K 7/087 flux-sensitive, e.g. magnetic, detectors G06K7/10336 takes precedence
• CPC Class Codes: G07D 7/04 Testing magnetic properties of the materials thereof, e.g. by detection of magnetic imprint G07D7/01 takes precedence

Abstract

A method of checking value documents having a security element with a plurality of magnetic areas, including a high-coercivity magnetic area, a low-coercivity magnetic area and a combined magnetic area, which contains both the high-coercivity and the low-coercivity magnetic material. When all magnetic areas have been magnetized in a first direction, second magnetization is performed, which involves only the low-coercivity magnetic material being remagnetized parallel to the first magnetization in the opposite direction, but the high-coercivity magnetic material remaining oriented in the first direction of magnetization. Next, first magnetic signals from the security element are detected using a first magnetic detector, and second magnetic signals are detected using a second magnetic detector. The magnetic signals are used to identify each magnetic area of the security element as a high-coercivity, a low-coercivity or a combined magnetic area.

Claims

1-15. -15. (canceled)

16. A method for checking a value document having a security element with several magnetic regions, said magnetic regions having at least one high-coercive magnetic region which contains a high-coercive magnetic material with a first coercive field strength and at least one low-coercive magnetic region which contains a low-coercive magnetic material with a second coercive field strength which is lower than the first coercive field strength and at least one combined magnetic region which contains both the high-coercive and the low-coercive magnetic material, comprising the steps:

first, magnetizing the security element by a first magnetic field whose magnetic field strength is greater than the first coercive field strength, so that the magnetization of the high-coercive magnetic material and the magnetization of the low-coercive magnetic material are aligned in a first magnetization direction,

then, magnetizing the security element by a second magnetic field whose magnetic field strength is lower than the first coercive field strength but is greater than the second coercive field strength, the second magnetic field being oriented such that the magnetization of the low-coercive magnetic material through the second magnetizing is aligned antiparallel to the first magnetization direction,

detecting first magnetic signals of the security element by a first magnetic detector, and

detecting second magnetic signals of the security element by a second magnetic detector, before the detection of the second magnetic signals a third magnetic field acting on the security element.

17. The method according to claim 16, wherein the second magnetic signals of the security element are detected under the action of the third magnetic field.

18. The method according to claim 16, wherein the magnetic field strength of the third magnetic field is greater than the second coercive field strength and the third magnetic field is oriented such that the magnetization of the low-coercive magnetic material is aligned by the third magnetic field in a third magnetization direction which is oriented non-antiparallel to the first magnetization direction.

19. The method according to claim 16, wherein by the second magnetic detector second magnetic signals of one or several soft-magnetic regions of the value document are detected, and are disposed outside the security element;

and causing the third magnetic field to act on the soft-magnetic region during the detection of the second magnetic signal of the respective soft-magnetic region.

20. The method according to claim 16, wherein the at least one combined magnetic region is magnetized by the second magnetic field such that a resulting magnetization of the at least one combined magnetic region, which arises from the second magnetizing, at least approximatively vanishes.

21. The method according to claim 16, wherein the at least one combined magnetic region is configured such that the high-coercive magnetic material of the combined magnetic region and the low-coercive magnetic material of the combined magnetic region have substantially the same remanent flux density.

22. The method according to claim 16, wherein a magnetic region whose second magnetic signal exceeds a second upper threshold and/or undershoots a second lower threshold, and whose first magnetic signal neither exceeds a first upper threshold nor undershoots a first lower threshold, is identified as a combined magnetic region.

23. The method according to claim 16, wherein a magnetic region whose second magnetic signal exceeds the second upper threshold and/or undershoots the second lower threshold, and whose first magnetic signal exceeds at least one of the first upper threshold and undershoots the first lower threshold, is identified either as high-coercive or as low-coercive magnetic region.

24. The method according to claim 22, wherein the first magnetic signal of the security element has a first signal offset and that the first upper threshold lies above the first signal offset and the first lower threshold lies below the first signal offset.

25. An apparatus for checking a document of value which has a security element with high-coercive magnetic material of a first coercive field strength and with low-coercive magnetic material of a second coercive field strength, wherein the apparatus comprises successively along a transport direction of the value document:

a first magnetization device arranged to make available a first magnetic field which is configured for the first magnetizing of the high-coercive and of the low-coercive magnetic material in a first magnetization direction, the magnetic field strength employed for the first magnetizing being greater than the first coercive field strength,

a second magnetization device arranged to make available a second magnetic field which is configured for the second magnetizing of the low-coercive magnetic material in a second magnetization direction which is oriented antiparallel to the first magnetization direction, the magnetic field strength employed for the second magnetizing being lower than the first coercive field strength, but greater than the second coercive field strength, and

a first magnetic detector arranged to detect first magnetic signals of the security element,

a second magnetic detector arranged to detect second magnetic signals of the security element, and

a third magnetization device arranged to make available a third magnetic field, which is configured such that the third magnetic field, upon checking of the value document, acts on the security element before the detection of the second magnetic signals.

28. The apparatus according to claim 25, wherein the magnetic field strength of the third magnetic field is greater than the second coercive field strength and the third magnetic field is oriented such that the magnetization of the low-coercive magnetic material is aligned by the third magnetic field in a third magnetization direction which is oriented non-antiparallel to the first magnetization direction.

29. The apparatus according to claim 25, wherein the third magnetic field is oriented substantially perpendicular to a main sensitivity direction of the second magnetic detector.

30. The apparatus according to claim 25, wherein the first magnetization direction is oriented parallel or antiparallel to the transport direction of the value document.

26. The apparatus according to claim 26, wherein the third magnetic field is configured such that, upon checking of the value document, it acts on a section of the security element to be detected, after the detection of the first magnetic signal of the respective section and before the detection of the second magnetic signal of the respective section.

27. The apparatus according to claim 26, wherein the third magnetic field is configured such that it acts on the section of the security element to be detected, before and during the detection of the second magnetic signal of the respective section.