Diazo-type multicolor reproduction process

Claim 1

In a process for multi-color reproduction, which comprises: A. exposing image-wise a diazo-type photosensitive material to actinic light by exposing through an original sheet of an assembly, said assembly consisting of (i) an original sheet having opaque image areas and transparent or semi-transparent non-image areas on one surface and a color-forming layer containing at least one thermovolatile or sublimable azo coupler (a), said layer being located in only preselected areas which are contiguous with opaque image areas of said original sheet, said preselected areas being present in only a portion of the areas contiguous with said opaque image areas of said original sheet, and (ii) a diazo-type photosensitive material having a photosensitive layer containing at least one photosensitive diazonium salt (c), an acidic stabilizer and an azo coupler (b) having a substantially lower rate of coupling with the diazonium salt (c) under the developing conditions than that of the azo coupler (a) said original sheet (i) being superimposed on said diazo-type photosensitive material (ii) so that the color-forming layer comes into face-to-face contact with the photosensitive layer; B. heating said assembly to thereby heat-transfer said layer of the coupler (a) to the corresponding position on the surface of said photosensitive layer, said steps (A) and (B) being performed simultaneously or in the time sequence of (A) to (B) or (B) to (A); and C. contacting the exposed photosensitive material with a mixture of ammonia and steam or an alkali-containing aqueous liquid developer to thereby develop said photosensitive material, whereby in the unexposed latent image area of the portion to which the coupler (a) has been heat-transferred, a dye (c)-(a) having a certain hue or color is formed by the selective reaction of the heat-transferred coupler (a) with the diazonium salt (c) and at the same time, in the unexposed latent image areas to which the coupler (a) has not been heat-transferred, a dye (c)-(b) having a different hue or color from said dye (c)-(a) is formed by the reaction of the coupler (b) with the diazonium salt (c), thus producing a multi-colored copied image, the improvement wherein in addition to the thermo-volatile or sublimable coupler (a), the color-forming layer contains a hue separation-improving agent selected from the group consisting of a. polyalkylene oxides having recurring units represented by the following formula --RO).sub. n wherein R is an alkylene group having 2 to 4 carbon atoms, and n is a number so selected that the polymer is solid under conditions of 20°C and one atmosphere pressure, b. carboxylic acid esters and ethers of polyalkylene oxide as described above, c. adducts between ethylene oxide or propylene oxide and stearic acid amide, lauric acid amide or oleic acid amide, and d. fatty acid amides other than said adducts, fatty acid imides, fatty acid aminoalkyl esters, fatty acid salts and condensates of fatty acid amide with formaldehyde, the melting point of which is 100°C or higher.