In an electrophotographic process without a decurler device, the amount of paper curl depends on the geometry of its transportation path. However, since the paper path affects the whole layout of the machine, it may not be modified even if the paper curl turns out to be out of acceptable range. To overcome the difficulty, a simulation model to predict the paper curl formed by the transportation path geometry is developed so that the paper path can be designed considering the paper curl at the early stage of product development. The mechanical characteristics is measured by a thermo-mechanical analyzer, and expressed as the double Maxwell model. Given fuser device and paper condition, the paper curl is calculated using the time variation of paper deflection during transportation. With three different types of paper, it is verified that the present simulation model is able to predict the amount of paper curl accurately.