Optimum toner charging and mass transfer are important factors to produce fine images with high quality in electrophotography. Also the uniformity of the image is one of the most important properties to produce high quality printing. The charging mechanism of toners and the mechanism of toner development in the electrophotographic monocomponent laser beam printer system was studied in this article. Development rollers with various surface properties were prepared. The dynamics of toner charging were investigated by using a current measurement technique. A current was observed to flow through each system part, i.e., development roller, blade, and supply roller, during the roller rotation with toner attached on its surface. Currents and toner charge to mass ratio and the uniformity of printing image were measured for each roller. It was found that the current had a strong relationship to the roller surface properties. It was also shown that the relationship between toner charge and roller surface properties is related to the uniformity of printing image. Finally the mechanism of toner development is discussed, and the design of a high quality development roller is proposed.