Electrophotographic production of colour photoconductive mosaic material

Claim 2

A process according to claim 2 which comprises using two patterns of light to which the photoconductive material is exposed in a first exposure b and in a second exposure e which are such that the areas of the final colour photo-conductive material which are sensitive to only one of the three regions of the spectrum are equal.

Claim 3

A process for the production of colour photo-conductive material of the mosaic type, wherein areas of the material are sensitive only to selected regions of the visible spectrum, from spectrally unsensitised photo-conductive material, which comprises either a photo-conductor layer coated on an electrodonductive layer which is in its turn coated on a support base or a photo-conductive layer coated on a support base which is or has been rendered electroconductive, which comprises the steps of a. charging the surface of the photoconductive material, b. exposing the surface of the material to light of such wavelength to which the unsensitised photoconductor layer is sensitive through a screen which comprises a series of lines which are opaque to the said light. c. toning the areas remaining charged on the surface of the photoconductive material by means of a dye sensitiser which sensitises them to light of one of the selected regions of the spectrum; d. recharging the surface of the photoconductive material, e. exposing the surface overall to light which comprises all the regions of the visible spectrum to which areas thereof have been sensitised thereby to destroy the charge on the material selectively in such areas, f. prior to, or at the same time as, or after this overall light exposure, exposing the surface of the material to light of such wavelength to which the unsensitised photo-conductor layer is sensitive through a screen which comprises a series of lines which are opaque to the said light, the lines of the screen in this exposure crossing at an angle to the direction of the lines during the exposure is carried out in b, g. toning the areas remaining charged on the surface of the photoconductor by means of a dye sensitiser which sensitises them to light of a selected region of the spectrum to which no area of the surface of the material is at present sensitive, and then h. recharging the surface of the photoconductive material i. exposing the surface of the material overall to light which comprises all the regions of the visible spectrum to which areas thereof have been sensitised thereby to destroy the charge on the material selectively in such areas, j. toning the areas remaining charged on the surface of the photoconductor by means of a dye sensitiser which sensitises them to light of a selected region of the spectrum to which no area of the surface of the material is at present sensitive.

Claim 4

A process according to claim 4 which comprises using in the first screen exposure of stage b, a screen in which the area occupied by the said opaque lines is a third of the area of the screen.

Claim 5

A process according to claim 5 which comprises using a screen wherein each opaque line is of the same width.

Claim 6

A process according to claim 4 which comprises using in the first screen exposure a screen comprising a series of lines which are opaque to all light.

Claim 7

A process according to claim 4 which comprises using in the second screen exposure of stage f a screen whereby the area occupied by the said opaque lines is one half of the area of the screen.

Claim 8

A process according to claim 8 which comprises using a screen wherein each opaque line is of the same width.

Claim 9

A process according to claim 4 which comprises using in the second screen exposure of stage f a screen comprising a series of lines which are opaque to all light.

Claim 10

A process according to claim 4 which comprises using in the second screen exposure a screen comprising a series of lines which are opaque to light of that region of the spectrum to which the unsensitised photoconductor layer is sensitive but which transmit light in that region of the spectrum to which the areas of the photoconductive layer toned in step c are sensitive.

Claim 11

A process according to claim 4 which comprises using in the second screen exposure of stage f a screen wherein the lines cross the direction of the lines in the first screen exposure of stage b at right angles.