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, the process comprising:

• classifying microcapsules for electrophoretic display devices from a dispersion containing microcapsules in an aqueous medium using a particle classification apparatus including 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 particle classification 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,
• wherein the connecting flow passage includes 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,
• wherein at least a lower portion of the connecting flow passage is immersed from above the dispersion reservoir into the dispersion contained in the dispersion reservoir,
• wherein a classifying section formed by the conical part and the barrel part is located outside and above the dispersion reservoir, and
• wherein the particle classification apparatus further includes a particle trapping part for trapping particles from the dispersion flowing out of the classifying section through the discharging flow passage.