In order to describe the liquid immersion development, electrophoretic mobility is important value because toner particles move in non-polar liquids when voltage is applied. Viscosity is known to influence the electrophoretic mobility, which effect is very considerable especially in high concentration and low shear rate. Generally speaking, viscosity of suspension is a function of various factors such as particle concentration, shear rate, temperature, and particle shape, etc. Even though temperature and concentration equal in liquid toner, viscosity of liquid toner is considerably influenced by shear rate and particle shape.In development of liquid toner from developer roll to photoreceptor, toner particles experience shear flow resulting from velocity difference between developer roll and photoreceptor. However, most discussions about liquid toner development systems have concentrated on the effect of electrostatic force and ignored that of shear rate or particle shape.In this work, three types of liquid toners with different particle shape were used to investigate the effects of shear rate and particle shape on the viscosity of liquid toners. From this work, it could be understood that the shear rate and particle shape of liquid toners influenced the viscosity of liquid toners under the same concentration and temperature. To describe the rheological behavior of the liquid toners quantitatively, modified Quemada equation, based on the hard sphere concept, was used. When η₀ in the Quemada equation was used as a function of shear rate and particle shape, it could be observed that the modified equation well described the viscosity of the liquid toners for all shear rates and concentration.