This numerical study was inspired by an intriguing experimental observation of some unexpected motion of “toner sheet” in a plate-out cell. In this report, numerical models for electrophoretic deposition of liquid toner are described. It takes into account the space-charge effect. The numerical results indicate that the toner deposition is strongly influenced by the space charge accumulation in a stationary plate-out cell. The motion of “toner sheet” gives a good indication of the charging characteristic of the liquid toner and other charged species, co-ion or counter ion, in the liquid inks. By comparison of numerical and experimental observation of the motion of toner in regular liquid inks, for example, it can be concluded that toner mobility is roughly an order of magnitude higher than the other charged species existed in the inks.