| 摘要 |
PURPOSE: To maintain the cleaning effect for a photoreceptor even when the printing density in the initial stage is low, by using vinyl polymer fine resin particulates having a specified range of primary particle size and preparing the particles in a specified aggregated state. CONSTITUTION: The resin particulates are prepared to have 0.1 to 0.5μm average primary particle size and to contain 5 to 90vol% aggregated particles having 0.5 to 30μm size in the whole particles. As for the resin particulates, generally, vinyl org. fine particulates are preferably used because these particulates can be easily produced by a method such as emulsion polymn. and suspension polymn. Especially as the most preferably material, vinyl halides such as vinylidene fluoride or copolymer of styrene and acrylates or methacrylates esters are used. As for the polymn. initiator necessary to synthesize resin particulates, peroxide such as benzoyl peroxide or azo polymn. initiator such as azobis isobutylonitrile can be used.
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