[en] Inorganic black particles (Black 444) were modified with poly(methyl methacrylate) as a shell material by using dispersion polymerization to improve their dispersion stability in a medium oil for electrophoretic display applications. They were also positively charged with vinylimidazole to enhance their electrophoretic mobility. The morphology and the shape of the composite particles were characterized by using scanning electron microscopy. The thermal properties and the chemical structure of the samples were examined by using thermogravimetric analysis and Fourier transform infrared spectroscopy, respectively. In addition, the electrophoretic mobility and the zeta-potential of the black444 /PMMA /vinylimidazole particles in a dielectric fluid were measured by using optical microscopy and electrophoretic light scattering. With increasing positive charge, the black444 /PMMA /vinylimidazole particles showed improved electrophoretic characteristics compared to pristine Black 444.