Carbon black is widely used as a black pigment in electrophoretic displays. The carbon black is required to control the density and surface charge depending on dielectric fluid to achieve a black image under the electric field. Both of them are closely related to the uniform polymer coating on the carbon black. Batch reactors have been used to carry out the polymerization on the carbon black. However, coating uniformity is not adequate when polymer coating is performed with a conventional batch system because it is difficult to maintain a uniform fluidic motion and mass transport throughout the batch reactor. Thus, a Couette-Taylor vortex reactor, generating uniform shear stress and fluidic motion, is used to coat the carbon black with a polymer. In this study, the influences of process variables in the Couette-Taylor vortex reactor on the properties of the synthesized black pigments are investigated. Because of strong agitation and uniform fluidic motion driven by the Couette-Taylor vortex, more uniform and smaller black pigments are obtained, resulting in the enhanced movement of the black pigment under an electric field. The productivity of the pigment is also improved along with the enhanced properties of the black pigments when using a continuous Couette-Taylor vortex reactor. (C) 2014 Elsevier Ltd. All rights reserved.