Identification code for documents and the like and unit for sensing magnetic codes

Claim 2

An identification code for documents and the like comprising a plurality of magnetic regions (1) which are mutually separated by spaces (2), characterized in that at least one first part (1a) of said regions has a magnetic coercivity which differs from that of the remaining regions (1b) of said plurality of regions, said different coercivity regions generating at least two different readouts of the same plurality of regions upon applying different magnetic fields for orientating said plurality of regions.

Claim 3

An identification code according to claim 1, characterized in that said magnetic regions (1) have diversifiable magnetic intensity.

Claim 4

An identification code, according to the preceding claims, characterized in that said regions (1) comprise a magnetic oxide layer.

Claim 5

An identification code, according to any of the preceding claims, characterized in that said regions (1) can be sensed by a magnetic sensing unit comprising, in the readout direction of said code, an entry magnet (10) for orientating all of said regions: a first read head (11) arranged after said entry magnet for generating a signal having pulses the position whereof is a function of the width of said regions and of said spaces, in the readout direction, and the amplitude whereof is a function of the intensity of the magnetic field generated by each of said regions after orientation; a de-orientation magnet (15) arranged after said first read head for generating a magnetic field capable of varying the orientation of the regions which have lower coercivity; and a second read head (16) arranged after the de-orientation magnet.

Claim 6

Identification code, according to any of the preceding claims, characterized in that said de-orientation magnet (15) generates a magnetic field in a direction which is substantially perpendicular to said entry magnet (10).

Claim 7

A unit for sensing magnetic codes according to claim 1, characterized by an entry magnet (10) which generates a magnetic field adapted to orientate a plurality of magnetic regions (1) defining a code; a first magnetic read head (11) arranged near to said entry magnet for generating an electrical signal having pulses the position whereof is a function of the width of the code regions and of the free spaces interposed therebetween in the read direction, and the amplitude whereof is a function of the intensity of the magnetic field generated by each code region; a de-­orientation magnet (15) arranged near to said first magnetic read head for varying the orientation of code regions which have lower coercivity; a second read head (16), arranged near to said de-orientation magnet; and an exit magnet (18) arranged near to said second read head for generating a magnetic field for orientating all the regions of said plurality of code regions.

Claim 8

A method for sensing an identification code according to claim 1, characterized by the steps of: - generating an electric field for orientating a plurality of magnetic regions defining a code; - reading the code by generating an electrical signal having pulses the position whereof is a function of the width of the magnetic regions and the amplitude whereof is a function of the intensity of the magnetic field generated by each magnetic region; - varying the orientation of the magnetic regions which have lower coercivity; and - reading the code defined by the magnetic regions having a same orientation.