A simplified simulation method coupling two-dimensional (2D) and three-dimensional (3D) models is proposed for analysis of primary toner transfer processes. In the 2D model, the electric potential distribution of a vicinity of a transfer nip is simulated including conditions and configurations of the transfer process. Meanwhile, the motion of toner particles is simulated with a 3D parallel plate model, including the relation between the electric potential of the intermediate transfer belt and the transfer gap obtained by the 2D simulation. The validity of the 2D and the 3D models is separately examined, and analyses of a primary transfer process in a printer have been demonstrated using the coupling method. The method has nicely reproduced transfer phenomena with small computational load.