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Article surveillance protection of flexible magnetic computer data storage disks

  • US 5,012,380 A
  • Filed: 08/24/1989
  • Issued: 04/30/1991
  • Est. Priority Date: 08/24/1989
  • Status: Expired due to Term
First Claim
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1. A computer disk having article surveillance protection comprising:

  • a flexible disk substrate having a central aperture and having a series of slits formed in the substrate around the periphery of the central aperture;

    a magnetic recording material formed on the surface of the disk on at least one side thereof for recording of data on the disk;

    and a surveillance marker comprised of an extended length of ferromagnetic material formed around at least a substantial portion of the periphery of the central aperture and integrally bonded to said disk substrate overlying the slits formed in the substrate, said slits being adapted to provide tear-initiation sites which operate to induce tearing of said flexible substrate in the event of an attempt to remove said marker from said substrate after said marker has been integrally bonded to said substrate.

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