Electro photographic process for colour proof prodn. - using thin transparent film between original and photoconductor during exposure to reduce dot broadening

摘要

In a process for forming a charge image on a preViously charged photosemiconductor material (I) by exposing the (I) to radiation through an original, the improvement that a thin layer of light-transmissive material (II) is placed between the image side of the original and the (I) during the exposure. The (II) is esp. a discrete film 0-100, esp. 3-20 microns thick e.g. of polyester, or the (II) may be in the form of a coating on the emulsion side of a photographic film. The process is esp. useful for prodn. of colour printing proofs using known electrophotographic methods starting with colour sepn. dot originals. The presence of the (II) reduces the broadening of the dots which occurs during exposure in the absence of (II) and thus gives colour proofs with better colour rendering.