Apparatus for invalidating security prints printed on print carriers

Abstract

The apparatus has as many invalidating units (E) arranged next to one another as there are longitudinal rows of security prints on the print carriers (P). Each invalidating unit (E) has a stand (1), a trough (3) vertically displaceable in the latter and intended for receiving ink (4), a centrifugal wheel (7) rotating continuously above the trough (3), and a shutter (11) which interacts with an orifice (10) of a cowl (9) covering the centrifugal wheel (7). By means of a controlled actuating member (6), the trough (3) is adjustable between a raised working position, in which the centrifugal wheel (7) dips into the ink and the shutter (11) exposes the orifice (10), and a lowered position of rest, in which the centrifugal wheel (7) does not dip into the ink and the orifice (10) is covered by the shutter (11). Control takes place whenever a security print previously detected as a misprint and to be invalidated in one or more longitudinal rows of the print carriers passes the orifice (10) of the respective invalidating unit, so that this misprint is sprayed with ink by the centrifugal wheel (7) through the orifice (10) which is then free.