To allow dispersion to proceed rapidly in a dispersion containing particles of Y type phthalocyanine as an electric charge generating material while avoiding the change of the crystal form of the Y type phthalocyanine to A type without requiring the removal of additives and a special post-treatment after dispersion because the use of additives and a special pretreatment are not required before dispersion and carrying out precise control of dispersion conditions and to prepare a coating fluid for an electrophotographic photoreceptor having a reduced average particle diameter.

A dispersion containing an electric charge generating material of ≤125 μm maximum particle diameter is fed into a bead mill dispersing apparatus with a dispersion chamber 1 containing a rotor which rotates at high speed and beads for dispersion, a circulation tank 3 into which the dispersion enters a feed pipe and a circulation pump 5 for pumping the dispersion from the tank 3 into the dispersion chamber 1 and a discharge pipe which connects the chamber 1 to the tank 3. The dispersion is circulated between the chamber 1 and the tank 3 and the objective coating fluid for the production of an electrophotographic photoreceptor containing fine particles of the electric charge generating material is prepared.