Magnetic fluid

摘要

This invention provides a magnetic fluid having a rich hue and containing an organic compound as dispersion medium. The magnetic fluid of this invention is constructed by mixing, into a magnetic dispersion, a colorant prepared by beforehand treating a coloring material with a solubilizing treating agent or a dispersibilizing treating agent. Said solubilizing treating agent or dispersibilizing treating agent has a hydrophobic group and a functional group absorbable or linkable to said coloring material. As said coloring material, a dyestuff, an organic pigment or an inorganic pigment is used. A colorant prepared by subjecting an intermediate of said coloring material to said treatment is also usable. Further, a colorant prepared by pretreating a coloring material so as to give the coloring material an absorbability or a linkability to said solubilizing treating agent or dispersibilizing treating agent and then subjecting the beforehand pretreated coloring material to said treatment is also usable. The magnetic fluid of this invention can retain its initial hue stably for a long period of time, and its hue can be changed without substantially changing the properties of magnetic fluid such as magnetization, viscosity and the like. Accordingly, the magnetic fluid of this invention can be applied extensively to all the use fields of magnetic dispersion, and it exhibits a particularly great effect when applied to uses of developer or ink in the field of printing and recording.