Toner charge is significant in an electrophotographic printing process. The characteristics of toner charge depend on various factors such as charging method, charge control agents, and environment in two-component developer system. Charge distribution is an important factor in toner and developing system. Toner charge distribution is affected by toner weight percent in two-component developer. Generally, the value of the average toner charge decreases when toner weight percent increasing. In this study, we have investigated the variation of toner charge distribution as the new toner is added for using two types of carriers such as ferrite carrier and carrier of the Imaging Society of Japan. According to the experimental results, the toner charge distributions are similar between toner added case after toner changed stationary state and ordinary toner charging case when toner is mixed with ferrite carrier. On the other hand, a clear difference of toner charge distribution is found by compared with previously cases when toner is mixed with STD carrier.