New numerical method to compute toner melting behavior in the fuser nip was developed by combining the recently proposed CCUP method known as a general solver for gas, liquid and solid and the Leonov model as a rheological model. In present method, deformation of the piled up powder toners by heat and load were computed using the fitted dynamic property of the viscoelastic parameters: G', G” and the WLF equation. In this study, effects of the fusing temperature, the nip load and the process speed on melting behavior were investigated. Consequently, the computed toner pile height and the surface roughness show good correspondence with experimental ones, and the validity of the present method was demonstrated.