The roles of counter-charges in toner charging and toner deposition processes for single-component development are studied by quantitative analyses of charge injection into and transport through the development rollers, taking into consideration the non-Ohmic nature of the semi-insulating overcoat layer of the rollers. The electrical requirements for the roller coatings, especially as a consequence of increased printing speed, are elucidated. Based on the findings, an ideal evaluation technique for development roller performance is suggested.