Nowadays the two-component developers are widely used in electrophotography. In two-component developing system toner is tribo-electrically charged by contacting with carrier. In this study, two types of crushed toners categorized according to the constitution of external additives and four types of carriers which are also categorized according to the surface treatment were used for the experiment. The toner charge distribution is changed by the type of carrier coating and concentration of external additives as well. The Aerodynamic size and electrostatic charge distribution of the toner particles are measured individually by E-SPART (Electrical Single Particle Aerodynamic Relaxation Time) analyzer.