While various types of
powder paints of different hues are mixed with each other without melting for
preparation of a powder paint of a desired hue, a fluidity improver possessing a
charge control function is simultaneously mixed into the powder paints without
melting. The mixed powder paint containing fluidity improver is charged, and
then electrostatic powder coating is performed by the charged powder paint. The
fluidity improver also acts as a charge control agent, which allows the powder
mixture to be electrostatically sprayed without significant separation of the
various powders. Suitable fluidity improvers include silica, aluminum oxide,
titanium dioxide, various titanates and other fine particle size inorganics.
Also described is the apparatus for mixing the fluidity improvers with the
powder mixture and stabilizing the electrostatic charges on the particles.