Duplicating method

Claim 1

Continuous duplicating method in which an inked ribbon is continuously moved into and out of a printing station into transfer position between a copy sheet and a printing member, ink being transferred from said ribbon to said copy sheet by means of energy applied to said ribbon by said printing member each time said ribbon enters said printing station, comprising the steps of providing an ink-impervious plastic film ribbon selected from the group consisting of chemically-oleophilic plastic films, plastic films which are treated to render them chemically-oleophilic and plastic films which are etched or coated to render one surface porous and physically-oleophilic having an ink-transfer surface which is receptive to liquid non-drying oil ink, contacting said ink-transfer surface with an ink-application roller containing a supply of liquid non-drying oil ink comprising liquid non-drying oil and pigment to apply a uniform, continuous, thin coating of said liquid non-drying ink to the ink-transfer surface of said plastic film ribbon, moving said ink-coated plastic film ribbon to said transfer position and applying a printing energy against the uncoated surface of said plastic film ribbon by means of said printing member to cause corresponding portions of said liquid ink coating to transfer to said copy sheet, moving said plastic film ribbon out of said transfer position, applying an additional amount of said liquid non-drying ink to the ink-transfer surface of said plastic film ribbon, at least in areas from which said ink has been transferred to said copy sheet, and reintroducing said ink-coated plastic film ribbon to transfer position in said printing station.