Abstract: A receiver sheet for thermal transfer printing comprises a sheet-like substrate supporting a backcoat comprising a cross-linked organic polymer which is a reaction product of a polyalkylene glycol and a polyfunctional organic cross-linking agent reactive with the terminal hydroxyl groups of the polyalkylene glycol. This provides a surface which may be written on using aqueous inks, and to which water-activated adhesives may adhere. Suitable cross-linking agents are hexamethoxymethylmelamines or oligomers thereof. The backcoat is free from alkali metal salts to avoid retransfer problems, and may also be textured by particulate material embedded in the cross-linked polymer, to improve handling properties.

Abstract: A receiver sheet for thermal transfer printing comprises a substrate having a dye-receiving side and a backcoat on the other side, characterised in that the major component of the backcoat is a partially esterified styrene/maleic anhydride copolymer. This provides a surface which can readily be written on using aqueous inks or ball pens, and can be adhered to by water-activated adhesives. It is also resistant to retransfer of dye from an underlying print, e.g. during storage. The backcoat may also contain antistatic agents and fine inert particles to improve handling properties, appearance and tooth.

Abstract: A thermal transfer receiver sheet with improved handling properties comprises a sheet-like dielectric substrate supporting a receiver coat of dye-receptive material on one side, characterized in that there are antistatic treatments provided on both sides of the dielectric substrate, such treatments being sufficient on each side to reduce the surface resistivity to less than 1.times.10.sup.13 .OMEGA./square. The side of the substrate remote from the receiver layer suitably has an antistatic backcoat for reducing the surface resistivity on that side, and the use of a textured surface provided by particulate materials either in the antistatic backcoat or in a further backcoat overlying the antistatic backcoat, may further improve the handling properties.

Abstract: A receiver for dye diffusion thermal transfer printing comprises a substrate supporting a receiver coat comprising a dye-receptive material and a dye permeable release agent, characterized in that the receiver coat also contains dissolved or dispersed therein a Bisphenol A-based unsaturated polyester adhesive, to reduce printing adhesion.

Abstract: An inkable sheet comprises a base sheet, such as a PET film, having on a surface thereof an ink-absorbent resin matrix comprising a vinyl pyrrolidone polymer and an ester of cellulose containing free carboxylic acid groups. A preferred matrix additionally comprises a vinyl alcohol polymer.

Abstract: Reflex copying of original materials, normally having an opaque background, onto light-sensitive vesicular imaging materials wherein exposure to light is effected through a screen which transmits the incident light in separate bundles of light rays.

Abstract: Vesicular recording materials incorporate a sensitized layer comprising, as vehicle for the sensitizing agent, a quaternized polyelectrolyte, e.g. preferably polymers of dimethylamino ethyl methacrylate. The water sensitivity of the preferred polymers is reduced by copolymerisation with insolubilizing comonomers such as itaconic acid.

Abstract: Modifying the surface of a diazotype material by incorporating an acrylic or methacrylic polymer into the diazotype sensitizing coating composition or coating the assembly with it so as to roughen the surface of the material thereby enabling nitrogen, which is liberated when the material is exposed to light, to escape from between the master and the diazotype material to prevent nitrogen accumulating between the two and hence avoiding slippage of one relative to the other.