Magnetic testing of valuable documents

US11263854B2 · kind B2 · utility

Assignee

• GIESECKE+DEVRIENT CURRENCY TECHNOLOGY GMBH · DE

Inventors

• Jurgen Schutzmann · Brackenheim, DE
• Steffen Schmalz · Munich, DE

Key dates

• Filing date: Oct 25, 2019
• Grant date: Mar 1, 2022
• Expiry date: Oct 25, 2039

Classification

• Technology area (CPC G): Physics
• CPC primary: G07D7/04
• WIPO field: Control
• WIPO sector: Instruments

Abstract

The magnetic checking of value documents with highly coercive and/or lowly coercive magnetic regions, involves after the magnetization of all magnetic regions in a first direction, a second magnetization is effected, in which only the lowly coercive magnetic material is re-magnetized, but the highly coercive magnetic material remains aligned in the first magnetization direction. Magnetic signals are detected with an inductive magnetic detector, having several measuring tracks transverse to the transport direction of the value document. To evaluate the magnetic signals of the measuring tracks, the strongest two local minima and/or maxima of the respective magnetic signal are ascertained by a measuring track as a function of time. A minima comparison value and/or maxima comparison value of the respective measuring track is determined. The magnetic coding of the security element is checked on the basis of the minima comparison values and/or maxima comparison values of the measuring tracks.