Rheological properties of microcapsule ink were investigated using a cone-and-plate type rheometer. The ink consists of microcapsules, of which diameter is about 2μm, and UV curable oligomers as a disperse medium. In steady shear flow the viscosity decreases with increasing the shear rate in the region under 0.05s-1. This phenomenon is attributable to breaking down of the network structure formed by microcapsule particles under the shear. Dilatant behavior was also observed in a certain shear rate range between 0.05 and 0.2s-1. In order to investigate the peculiar flow behavior, we measured the flow properties of various disperse systems of microcapsules having different core and shell stiffness.
