| 摘要 |
A method of validating magnetisable elements in sheet material to be used for security documents includes the steps of subjecting each element to a magnetic field 50, producing relative movement between the element and the magnetic field, sensing any residual magnetism in the element using a read head 54 at a point remote from the magnetic field, generating electrical signals indicative of the residual magnetism, processing the electrical signals to determine whether or not the residual magnetism is correct for the sheet material concerned, and routing each sheet to an appropriate destination. The method may include the steps of generating signals indicative of the type of flaw detected, marking any sheet that contains a flaw, and diverting flawed sheets to different destinations depending on the type of flaw detected. |
