| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for obtaining a silica based fine particle external additive for small particle size toners, having high dispersibility and low cohesiveness.SOLUTION: A method for manufacturing a silica based fine particle toner external additive for electrostatic charge development comprises the steps of: adding a mixture of an alkyl silicate shown by SiO(OR)-(-SiO(OR)-)-Si(OR)(where, Ris the same or different kind of 1-6C alkyl group, and m is 1 to 100) and a hydrophilic organic solvent to a mixed solution of a hydrophilic organic solvent and water to obtain a dispersion liquid of hydrophilic silica particles by hydrolyzing and condensing the alkyl silicate; (B) introducing RSiOunit (where, Ris a substituted or unsubstituted 1-20C monovalent hydrocarbon group) on the surfaces of the hydrophilic silica particles to obtain hydrophobic silica fine particles; and (C) introducing RSiOunit (where, Ris the same or different kind of a substituted or unsubstituted 1-6C monovalent hydrocarbon group) on the surfaces of the obtained hydrophobic silica fine particles.</p> |
