Letraset USA Inc.

Esselte Pendaflex Corporation

Letraset Corporation

Simon L Scrutton

John V Shepherd

David R Wilson

William F Marwick

Eric M Sutton

John S Thornley

Multi-colored images are built-up from thermoplastic, separation negatives obtained for example on a laser printer. Colored positive separations are obtained by applying a colored, transferable non-thermoplastic layer on a carrier over each thermoplastic negative separation, subjecting the assembly to heat and pressure, and peeling apart the assembly whereby colored non-thermoplastic positive images remain on the carrier sheet. Each colored non-thermoplastic positive separation in turn is then transferred to a receptor having a thermoplastic surface. Each colored, non-thermoplastic positive is applied over the receptor having a thermoplastic surface, the image being in contact with the thermoplastic surface, the assembly is subjected to heat and pressure and the carrier sheet removed to leave the positive image adhered to the thermoplastic surface of the receptor. This process is repeated for each color positive separation to build up the multi-colored image on the receptor surface.

Coloured images

Transfer material is prepared by applying to a substrate a layer of a photosensitive material which is insoluble but swellable in the solvent used to develop the image and whose adhesion to the substrate increases on exposure to light, imagewise exposing the material and developing the so-exposed material by treatment with a solvent fully to remove unexposed material from the substrate and, if necessary, treating the remaining areas of the exposed material to render them transferable from the substrate. In this manner the full thickness of the photosensitive material layer may be retained in the final transfer material. In particular, adhesive material may be applied to the layer photosensitive material before imagewise exposure, and the adhesive coated material imagewise exposed and developed to remove photosensitive material and adhesive in the non-exposed areas only to leave adhesive coated image indicia.

Production of transfer material

A method of making signs is disclosed in which a photographically sensitive material is imagewise exposed and developed. The developed image is so constituted that, under the action of heat and pressure, it may be made to adhere to a surface of a transparent or translucent sheet, e.g. of plastics or glass, to form a sign in which the legend is visible through and protected by the sheet. In order to render the legend more visible, a coating or layer may be applied over the legend which accordingly forms a background to the legend as viewed through the sheet. Production of the legend photographically gives very great flexibility in terms of letter size, spacing and the like and allows the production of 'one off' signs on a rapid and economic basis. A simple hot press may be used to adhere the legend to the sign sheet.

Manufacture of signs using photoimaging and heat transfer

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London, United Kingdom

Simon L Scrutton