| 摘要 |
PROBLEM TO BE SOLVED: To provide silica fine powder treated by surface treatment with a silane coupling agent containing an amino group and having small cohesiveness, an easy method for manufacturing the same, and an external additive for positively electrified toner, consisting of the same and superior in printing property persistent effect. SOLUTION: There are provided: the silica fine powder in which the spherical silica powder having a primary particle mean diameter of≤1μm is treated by the surface treatment with the silane coupling agent containing the amino group and in which the number of detected aggregated particles by the grain gauge method according to JIS K 5400 is≤2; the silica fine powder further treated by hydrophobic treatment with a hydrophobic silane coupling agent and/or a silicone oil; the external additive for the positively electrified toner, consisting of the silica fine powder; and the method for manufacturing the silica fine powder. COPYRIGHT: (C)2005,JPO&NCIPI
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