METHOD AND DEVICE FOR PRODUCTION OF COUNTERFEIT-PROOF PAPER WITH TWO WINDOW-TYPE PROTECTIVE ELEMENTS Russian patent published in 2020 - IPC D21F11/00 

FIELD: paper.

SUBSTANCE: invention relates to a method of producing counterfeit-proof paper with at least two endless, visible on opposite sides of the counterfeit-proof paper with window-type protective elements, in which in the first device for making paper layers a first paper web is formed, and when forming sheet in first paper web first endless protective element is introduced in form of protective element of window type, in second device for making paper layers second paper web is made, second paper web is brought together and tightly connected to the first paper web such that the first endless security element is freely available in the window areas of the first paper web, when paper sheets are brought together between the first and second paper web, a second endless security element is built in, and by means of a suction and/or flushing device from the second paper web, in the wet state, paper fibres such that second endless security element is freely accessible in window areas of second paper web.

EFFECT: technical effect is to provide protection against falsification.

15 cl, 4 dwg