Method of manufacturing printed circuits

Claim 1

IN THE METHOD OF MANUFACTURING PRINGED CIRCUITS WHICH COMPRISES EXPOSING AN ELECTROSTATICALLY CHARGED PHOTOCONDUCTIVE INSULATING SURFACE TO A LIGHT IMAGE OF THE DESIRED CIRCUIT PATTERN TO FORM A LATENT ELECTROSTATIC IMAGE OF SAID PATTERN, DEVELOPING THE LATENT ELECTROSTATIC IMAGE WITH AN ACID RESISTANT POWDER AND TRANSFERRING SAID ACID RESISTANT POWDER IMAGE THEREBY DEVELOPED TO AN ACID ETCHABLE METALLIC SURFACE, AND ETCHING THE UNCOVERED PORTIONS OF THE METALLIC SURFACE, THE IMPROVEMENT WHICH COMPRISES TRANSFERRISNG SAID DEVELOPED POWDER IMAGE FROM SAID PHOTOCONDUCTIVE INSULATING SURFACE TO A FLACCID TRANSFER SHEET BY PRESSING THE SURFACE OF SAID SHEET AGAINST THE DEVELOPED POWDER IMAGE ON SAID PHOTOCONDUCTIVE INSULATING SURFACE, SAID SURFACE OF SAID TRANSFER SHEET HAVING THE PROPERTY OF ADHERING TO THE DEVELOPED IMAGE WITH A TENACITY GREATER THAN THAT OF THE IMAGE TO THE PHOTOCONDUCTIVE INSULATING SURFACE, THE SURFACE OF SAID TRANSFER SHEET BEING SUFFICIENTLY PLIABLE TO ALLOW CONTACT WITH THE ENTIRE POWDER IMAGE WHICH HAS ONE PORTION EMBEDDED IN THE SURFACE OF THE TRANSFER SHEET AND ANOTHER PORTION PROJECTING THEREFROM WHEN SAID PRESSURE IS APPLIED, EXPOSING SAID ANOTHER PORTION TO A VAPOR OF A SOLVENT THEREFOR TO MAKE SAID ANOTHER PORTION TACKY WITHOUT DISSOLVING THE SAME, SAID ONE PORTION EMBEDDED IN THE SURFACE OF SAID TRANSFER SHEET REMAINS UNAFFECTED BY SAID VAPOR OF SAID SOLVENT, RETRANSFERRING SAID POWDER IMAGE BY BRINGING SAID TACKY ANOTHER PORTION INTO CONTACT WITH SAID METALLIC SURFACE AND PRESSING UPON SAID TRANSFER SHEET SO THAT SAID TACKY ANOTHER PORTION CONTACTS THE METALLIC SURFACE AND DISLODGES SAID EMBEDDED ONE PORTION FROM THE TANSFER SHEET DURING THE REMOVAL THEREOF, AND FUSING SAID ONE AND ANOTHER PORTIONS TO THE METALLIC SURFACE BEFORE ETCHING.