Appliance for the removal of air between a magnetic nut medium and a magnetic slave medium, before hysteresis-free transmission of data of a nut medium to the slave medium

摘要

A prerecorded magnetic master web (54) and an unrecorded magnetic slave web (14), such as a photographic film having a magnetic coating, are brought into intimate contact for anhysteretic recording by wrapping the moving master web partially around a small diameter gimballed roller (66) positioned in close proximity to a rotating transfer drum (36); wrapping the moving slave web partially around a larger idler roller (34) positioned in close proximity to both the gimballed roller and the transfer drum; wrapping the slave web partially around the transfer drum with the master web wrapped outside the slave web; and evacuating a chamber or volume (68) formed among the webs, rollers and drum, to remove air from between the webs and cause them to converge into intimate contact at a nip upstream of a signal transfer zone in which a magnetic head (70) applies a decaying magnetic field to cause anhysteretic transfer from the master web to the slave web.