METHOD FOR VERIFICATION OF BANK NOTE VALIDITY AND DEVICE WHICH IMPLEMENTS SAID METHOD Russian patent published in 1997 - IPC

FIELD: bank equipment. SUBSTANCE: method involves detection of presence or absence of magnetization in ink of ferromagnetic or para-magnetic material which is used for printing of grid or number on surface of security items, measuring and comparison of magnetic permeability of corresponding parts of grid of number of security item. Said method is implemented in device which has detector which is designed as wire coil with core which has space, and comparison unit. Operation surfaces of pole pieces of detector core which provide gap are located in single plane in parallel to surface of grid or number on security item. Total area of operation surfaces of pole pieces is of same order of magnitude as grid or number area of tested security item. Interference with external magnetic field is compensated by electromagnetic shield. EFFECT: increased reliability of checking, simplified design of method for checking. 3 cl, 2 dwg