SECURITY ELEMENTS, AND METHODS AND APPARATUS FOR THEIR MANUFACTURE

摘要

AN APPARATUS IS PROVIDED FOR MAGNETICALLY IMPRINTING INDICIA INTO A LAYER ON AN ARTICLE, THE LAYER COMPRISING A COMPOSITION IN WHICH MAGNETIC OR MAGNETISABLE PARTICLES ARE SUSPENDED. THE APPARATUS COMPRISES: A SOFT MAGNETISABLE SHEET, HAVING AN OUTER SURFACE ARRANGED TO FACE THE ARTICLE IN USE, AND AN OPPOSING INTERIOR SURFACE; AND A PERMANENT MAGNET, SHAPE SUCH THAT ITS MAGNETIC FIELD CONTAINS PERTURBATIONS GIVING RISE TO INDICIA. THE PERMANENT MAGNET IS DISPOSED ADJACENT THE INTERIOR SURFACE OF THE SOFT MAGNETISABLE SHEET. THE SOFT MAGNETISABLE SHEET ENHANCES THE PERTURBATIONS OF THE MAGNETIC FIELD OF THE PERMANENT MAGNET SUCH THAT WHEN THE LAYER TO BE IMPRINTED IS LOCATED ADJACENT THE OUTER SURFACE OF THE SOFT MAGNETISABLE SHEET, THE MAGNETIC OR MAGNETISABLE PARTICLES ARE ORIENTED BY THE MAGNETIC FIELD TO DISPLAY THE INDICIA.