In the transfer process of electrophotography, electrostatic forces caused by the transfer electric field act on a sheet in the nip region. As a result, the sheet sticks to the photoconductor drum and sheet transport fails. The authors have developed a numerical simulation method of sheet transport in the transfer process. The method calculates sheet transport by means of weak coupling between electric field and structural analyses and considers electrostatic forces acting on the sheet and displacement of components relative to each other. The authors used the method to calculate sheet transport in a system that consists of two rollers and the sheet between them. In this system, the sheet passes between two rollers which contact each other and to which a voltage is applied. The calculated charge density, discharges, and sheet displacement showed good agreement with experiments. Another analysis clarified the relationship between electric discharges in the nip region and the sheet sticking to the roller.