Toner composition comprising rosin modified styrene acrylic resin.

摘要

A rosin modified acrylic resin for use in a toner composition is provided. The resin is prepared by steam stripping a mixture of solution polymerized styrene-acrylic copolymer, rosin, and a suitable solvent, such as toluene or xylene, followed by cooling and grinding to form the styrene acrylic-rosin resin. This binder resin has an inherent positive charge of at least 2.0 in contrast to typical prior art toner binders which are inherently negatively charged. The binder resin is formulated with conventional coloring pigments, charge controlling dyes and carriers such as iron powder or glass beads to provide dry toner compositions of high positive charge. As a result of the inherent positive charge of the binder resin, the toner composition of this invention needs much less of an addition of charge control agent to bring the positive charge to the required +10 to +12; thereby leading to far lower manufacturing costs.