| 摘要 |
PURPOSE:To facilitate control of toner particles diameter and to sharpen a particle diameter distribution by forming a colored interlayer containing a specified aqueous medium and a specified resin and an outermost layer containing both of them on the surfaces of core particles. CONSTITUTION:The surface of each spherical polymer core particle 1 made of a vinyl type polymer or the like having a diameter of 1-30mum is coated with a colored aqueous dispersion containing the aqueous medium (A), the resin (B), and a pigment to form the colored interlayer 2 of 0.01-1.5mum thickness. The surface of the obtained interlayer 2 of each core particle is coated with an aqueous dispersion containing the medium (A) and the resin (B) and modifiers, such as wax and an electric charge controller, but no pigment to form the outermost layer 3 of 0.01-0.5mum thickness. It is preferred to use for the medium (A) a solvent having a solubility parameter of > 9, and also to use for the resin (B) a resin prepared by neutralizing a soap-free emulsion resin with an alkaline volatile substance and making it soluble in the medium (A) or dispersible in it down to a particle diameter of <=0.2mum. |
