| 摘要 |
<p>PROBLEM TO BE SOLVED: To relatively easily and inexpensively provide fine particles for a toner additive having high hydrophobicity and negative chargeability and excellent in fluidity and stability of the charged state against an environmental change. SOLUTION: Fine silica particles are coated with 1-30 wt.% hydroxide or oxide of one or more among titanium, tin, zirconium and aluminum based on the amount of the particles in a water system to prepare a slurry and further coating with 3-50 wt.% alkoxysilane based on the solid content of the slurry, neutralization with an alkali, filtration, washing, drying and comminution are carried out to produce the objective hydrophobic fine particles having high hydrophobic property and negative chargeability and useful as an additive for an electrophotographic toner for forming a copied image with a copying machine, a laser printer or the like.</p> |
