HYDROPHOBIZED SPHERICAL POLY (ALKYL SILSESQUIOXANE) MICROPARTICLES, EXTERNAL ADDITIVE FOR TONER, DRY ELECTROPHOTOGRAPHY TONER, AND METHOD FOR MANUFACTURING HYDROPHOBIZED SPHERICAL POLY (ALKYL SILSESQUIOXANE) MICROPARTICLES

摘要

Provided are: poly (alkyl silsesquioxane) microparticles that are hydrophobic and have a small particle diameter; an external additive for toner and a dry electrophotography toner using same; and a method for manufacturing hydrophobized spherical poly (alkyl silsesquioxane) microparticles. Hydrophobized spherical poly (alkyl silsesquioxane) microparticles for which the median diameter on a centrifugal sedimentation mass basis is in the range of 0.05 - 0.3 µm. Said microparticles are manufactured by passing at least through processes for mixing a starting material solution prepared using, for example, an alkyl trialkoxysilane with an alkaline aqueous medium to obtain a polycondensation reaction solution, then mixing said polycondensation reaction solution with an aqueous solution to obtain a microparticle dispersion, and then blending a hydrophobizing agent into said microparticle dispersion.