| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to easily produce a pigment dispersion liquid adequate for an electrophotographic photoreceptor by dispersing pigments for the electrophotographic photoreceptor by dry process dispersion down to a grain size below a specific value, then dispersing the pigments by wet process dispersion into an org. solvent down to an average grain size below a specific value. SOLUTION: The electrophotographic photoreceptor pigments are first dispersed down to the grain size below 250μm by the dry process dispersion. The dispersion down to the small grain size by the dry process dispersion is not efficient and, therefore, the pigments are preferably dispersed to the extent of allowing the passage of nearly the entire amt. through a sieve of a mesh opening 250μm and the passage of 20 to 50% thereof through a sieve of a mesh opening of 149μm. The pigments dispersed down to the prescribed grain size by the dry process dispersion are then slurried by the org. solvent and the slurry is supplied to wet process dispersion. The wet process dispersion is executed until the average grain size of the pigments attains <=0.5μm. The pigment dispersion produced in such a manner is formed as a coating liquid by adding a binder and various additives, etc., thereto if desired. This coating liquid is used for formation of a photosensitive layer.
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