Method and device for producing fraud-proof paper and fraud-proof paper

Abstract

The invention relates to fraud-proof paper and to a method and device for the production thereof. The inventive method consists in forming a first paper web provided with a protective band whose width is equal to or less than 2 mm and which is incorporated into the web during the formation thereof with the aid of a cylinder mould machine in such a way that free-access areas (windows) are formed on protruded elements of the face side of the web. Said protective band is incorporated into the first paper web during the formation thereof and after formation of the free access areas which is associated with the formation of a fibre layer representing 35-50 % of the mass of the first paper web. A second paper web devoid of the protective band is produced simultaneously with the first web and afterwards is applied to the back side thereof in such a way that when they are connected to each other the defects of the said back side are hidden. Afterwards, the thus obtained two-layer material is pressed and dried. The protruded elements are embodied in the form of waterproof elements. An additional protective element is incorporated into the first and/or the second paper web during the production thereof. For the purpose of said invention, a protective band having a width ranging from 2 to 20 mm and comprising additional protective elements is used.

Description

technical field [0001] The invention relates to a device and a method for producing anti-counterfeit paper and the paper produced by the method. Background technique [0002] Different elements, such as strips or threads, have been introduced in security papers for their protection and are also intended for the manufacture of banknotes, official documents and other similar uses. [0003] A method and a paper machine are known for producing security paper, according to which a security strip is fed onto a cage outside a fibrous material by placing the security strip on a raised part (projecting member) of the cage. Before dipping into the material where the strips (threads) are placed on the protruding member, the paper layer has not yet formed on the side facing the cage, so that the threads can freely and accurately contact the surface at these locations (see EP 0 059 056 A1, 1 September 1982). [0004] However, this method cannot form a sheet with broad lines and no defe...

AI Technical Summary

Problems solved by technology

[0009] 1. It cannot embed a security strip greater than 4mm wide into the first paper layer because there is not enough time for the pulp fibers to penetrate into the narrow gap between the security strip and the surface of the cage in the area between the protruding members ;

[0010] 2. It cannot form a free contact area (window) with a large distance between each ot

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