Process for magnetic marking of documents and valuables such as banknote paper

摘要

The process starts with the use of a metallic glass which is firstly pulverised and then dispersed in the printing ink, becoming therewith part of the paper forming the document or valuable in question during the actual operation of printing same, producing on said paper a uniform magnetic moment per unit of surface area covered with ink. Pulverisation takes place in a ball mill after the fragility of the metallic glass has been increased by means of its being cooled ultra-rapidly and then hydrogenated by means of electrolysis. Distinct marking for different types of documents or valuables is feasible by varying the concentration of amorphous magnetic powder supplied into the ink from one type of document to another or by varying the composition of the powder, i.e. the type of initial metallic glass used.