Process for producing microcapsules for electrophoretic display devices, as well as microcapsules for electrophoretic display devices, obtained by this process, and their applications

A process for producing microcapsules for electrophoretic display devices, comprising classifying microcapsules for electrophoretic display devices from a dispersion containing microcapsules in an aqueous medium, using:

• a particle classification apparatus having a connecting flow passage toward a dispersion reservoir, a conical part, a barrel part, and a discharging flow passage, in this order from a bottom side of the apparatus, wherein particles are classified from the dispersion contained in the dispersion reservoir by generating a circulating flow of the dispersion in the barrel part until the dispersion reaches the discharging flow passage from the connecting flow passage, and wherein the connecting flow passage is composed of a dispersion feeding flow passage for introducing the dispersion into the conical part and a dispersion draining flow passage for returning the dispersion to the dispersion reservoir, at least a lower portion of the connecting flow passage being immersed from above the dispersion reservoir into the dispersion contained in the dispersion reservoir, and a classifying section composed of the conical part and the barrel part is located outside and above the dispersion reservoir.