Patent ID: 8286551
Filing Date: 2012-10-16
Classification: B41F,B41M,B41P

Abstract:
1. A screen printing machine for printing a substrate in the form of a sheet or continuous web bearing impressions of security papers arranged in matrix form, comprising: a transfer system for conveying the substrate onto an impression cylinder; at least a first screen cylinder cooperating with the impression cylinder for applying a plurality of first ink patterns on the substrate, which first ink patterns are arranged in a matrix form corresponding to that of the security papers, the first ink patterns being made of a first optically variable ink containing magnetically orientable pigments; an unloading system for carrying the substrate away from the impression cylinder after printing by the first screen cylinder; a drying system for drying the first ink patterns applied on the substrate; and a first cylinder carrying a plurality of magnetic elements which are arranged in a matrix form corresponding to that of the first ink patterns, each magnetic element being designed to orient the magnetically orientable pigments contained in the first ink patterns before the first ink patterns are dried by the drying system, the first cylinder carrying the plurality of magnetic elements and the impression cylinder are the same cylinder; a second screen cylinder cooperating with the impression cylinder, downstream of the first screen cylinder, for applying a plurality of second ink patterns on the substrate, which second ink patterns are arranged in a matrix form corresponding to that of the security papers, the second ink patterns being made of a second optically variable ink containing magnetically orientable pigments; and a second cylinder, located downstream of the impression cylinder, carrying a plurality of magnetic elements which are arranged in a matrix form corresponding to that of the second ink patterns, each magnetic element being designed to orient the magnetically orientable pigments contained in the second ink patterns according to a determined orientation before the second ink patterns are dried by the drying system.