TONER COMPOSITION COMPRISING ROSIN MODIFIED STYRENE ACRYLIC RESIN

摘要

06-12(1892)A TONER COMPOSITION COMPRISING ROSIN MODIFIED STYRENE ACRYLIC RESIN of the Invention: A toner composition for use in electrophotography comprises a rosin modified styrene-acrylic binder resin which has been prepared by steam stripping a mixture of solution polymerized styrene acrylic copolymer resin, rosin and a suitable solvent such as toluene or xylene followed by cooling and grinding to form styrene acrylic/rosin binder resin. This binder resin is then 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. An important feature of the present invention is that the styrene acrylic/rosin binder resin will have an inherent positive charge of at least 2.0. This inherent positive charge is in contrast to typical prior art toner binders which are inherently negatively charged. As a result, 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.