EP 0088169 B1 19860212 - SYSTEM AND APPARATUS TO DETECT INTAGLIO PRINTING
Title (en)
SYSTEM AND APPARATUS TO DETECT INTAGLIO PRINTING
Publication
Application
Priority
CH 139582 A 19820308
Abstract (en)
[origin: US4594514A] A method is provided for observing, preferably through the medium of an optoelectronic pick-up, the carrier to be checked which is illuminated by a light beam having an angle of incidence of at least 45 DEG through a rotary disc comprising alternately transparent and opaque sectors spaced from one another by a distance at least substantially equal to the distance measured between the lines of the copperplated printing formed on the carrier. The carrier image is formed in the plane of a detector by means of an optical system. If the carrier has a copperplate printing formed thereon, a moiré effect is observed. If the pick-up extends over several transparent sectors of the disc this moiré effect is converted electrically into a very pronounced periodic variation of the current delivered by the pick-up, at the sector passage frequency.
IPC 1-7
IPC 8 full level
G07D 7/00 (2006.01); G07D 7/06 (2006.01); G07D 7/12 (2016.01)
CPC (source: EP US)
G07D 7/12 (2013.01 - EP US)
Designated contracting state (EPC)
AT BE DE FR GB IT NL SE
DOCDB simple family (publication)
EP 0088169 A1 19830914; EP 0088169 B1 19860212; AT E17971 T1 19860215; CH 645464 A5 19840928; DE 3269113 D1 19860327; JP S58154088 A 19830913; US 4594514 A 19860610
DOCDB simple family (application)
EP 82201645 A 19821221; AT 82201645 T 19821221; CH 139582 A 19820308; DE 3269113 T 19821221; JP 2136583 A 19830210; US 46233883 A 19830131