Apparatus for testing magnetic properties of sheet material such as bank notes or papers of value
AssigneeGiesecke & Devrient GmbH
InventorsMichael Bloss, Dieter Stein
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Abstract
For measuring magnetic properties of sheet material the sheet material is guided past a magnetic measuring system at a measuring distance defined between the sheet material and the magnetic measuring system. The sheet material is transported with a transport medium disposed between the measuring system and the sheet material. The measuring distance is determined substantially by the thickness of the transport medium. The thickness of the transport medium is selected to be smaller than a predetermined local resolution. If the local resolution is high enough it is also possible to detect magnetic printed images.
Claims9
An apparatus for testing magnetic properties of sheet material such as bank notes or papers of value with a predetermined local resolution comprising:
- at least one magnetic measuring system (30), and
- a transport medium (20) for guiding the sheet material (10) past the measuring system (30) at a measuring distance (21) defined between the sheet material (10) and the measuring system (30),
- characterized in that
- the transport medium (20) is disposed between the measuring system (30) and the sheet material (10),
- the measuring distance (21) is determined substantially by the thickness (22) of the transport medium, and
- the thickness (22) of the transport medium is smaller than the predetermined resolution.
Dependencies are inferred from the claim text.