We have analyzed tribo-charging characteristics on black toner particles in two-component developer. The electrophotographic characteristics on toner in the developer are affected by various factors such as material component, shape and methods of tribo-charging or measurement. It is, therefore, important to evaluate not only tribo-charging behavior but also the mixed state of toner particles and carrier beads in the two-component developer. For this purpose, yellow color toner particles instead of black toner are adopted in the developer for evaluation of tribo-charging characteristics. Tribo-charging on toner is performed by using the two types of shaker with different arm length, 130mm and 200mm, where the shaker with 130mm arm length is based on the recommended design by the ISJ. From the results of photographs on the outside appearance of mixed toner samples in a glass bottle, the completely mixed state for toner is obtained after 20min of mixing time at 150rpm with arm length of 130mm and also after 1 min of mixing time at 150rpm with arm length of 200mm. For the tribo-charging behavior, it is showed that the charge to mass ratio q/m is −12.5μC/g for 20min of shaking time at 150rpm with the 130rpm arm length shaker and −19.0μC/g for 1min at 150rpm with the 200mm. In the case of 120rpm with the 130mm, the q/m shows to be slightly charged values corresponding to the insufficiently mixed states.