The effect of the particle size upon electrophotographic properties of the plate which is coated with the β Cu-Pc have been studied. Two crystal forms of Cu-Pc namely α and β are well known, and β Cu-Pc is produced either by directly synthesizing from its raw materials (referred to as finished) or by transforming in aromatic solvents from α Cu-Pc (referred to as transformed). Electron microscopy observation revealed that the particle size of the finished β Cu-Pc was about 10 mμ in diameter and that of transformed β Cu-Pc was a few microns. The surface area of the former is approximately twice as large as that of the latter. This paper describes that the latter is more sensitive than the former to light.
Photoinduced discharge curve of the transformed β Cu-Pc shows no induction effect, but that of the finished β Cu-Pc has an obvious one.
The transformed β Cu-Pc decreases in its electrophotographic sensitivity as the grinding of it proceeds in a ball mill. These phenomena can be elucidated in terms of trapping of the excited carriers at the surface of pigment particles.

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KC-Plates are the most promising photomechanical plates for copy-dot projection and laser platemaking. They consist of an electrophotographic inorganic coating on a polyester or metal base with an exposure speed comparable with lith films; an ultimate resolution or 10,000 line pairs per millimeter; complete panchromatic sensitivity; no reciprocity failure; and no light scatter in the coating. The film has a number of other characteristics such as reuseability, add-on features and use directly as a printing plate. The manufacture and uses of KC-Coating are described. Its special attraction for graphic arts is its use as a plate for copy-dot projection printing and laser platemaking.

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