Two-stage contact duplication of magnetic signals utilizing a metal-backed intermediate

Claim 1

In a system for making direct-image copies of magnetic signals from a master magnetic recording medium onto a copy magnetic recording medium, each of which has a magnetizable face, which system includes 1. an intermediate having a face of magnetizable material which has a low Curie temperature relation to that of the master medium and high Hc relative to the Hc of the copy medium, 2. means for heating the magnetizable material of the intermediate to a temperature T1 approximating its Curie temperature but below the Curie temperature of the master medium, 3. means for moving the master medium and the heated intermediate in face-to-face contact while allowing the magnetizable material of the intermediate to cool below its Curie temperature to copy the magnetic signals from the master medium onto the intermediate, 4. means for subsequently separating the master medium from the intermediate, and 5. means for moving the copy medium and the separated intermediate in face-to-face contact through a magnetic field for stimulating the magnetizable material of the copy medium to copy the signals onto the copy medium, the improvement comprising: a. said intermediate is a tape or endless belt having a metal backing of low permeability, b. cooling means including a rotating surface which is refrigerated to withdraw from the intermediate at least AvdC(T1-T2) calories per second where A is the cross-sectional area in cm2, v is the velocity in cm/sec., d is density in gm/cm3, C is the specific heat in calories per gram, and T2 is the temperature of the intermediate when it leaves the refrigerated rotating surface, and c. said means for moving master medium includes means for forcing the master medium against the heated intermediate and the intermediate in turn against the refrigerated rotating surface to cool the magnetizable material of the intermediate by conducting heat away through the metal backing.