| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative charging toner comprising toner base particles obtained by aggregating/unifying phase-inversion emulsification resin particles of anionic self-water-dispersible polyester resin particles, the toner having excellent charging stability and durability and giving no unevenness to a printed image; and to provide a method for producing the toner. SOLUTION: The negative charging toner is obtained by externally adding external additive particles, which are subjected to a hydrophobicizing process with a silane coupling agent, to anionic self-water-dispersible polyester resin particles formed by phase-inversion emulsification with addition of a dispersion stabilizer and an electrolyte. Hydrophobic silica fine particles having a number average primary particle diameter of 7 to 60 nm and hydrophobic titanium oxide fine particles having a number average primary particle diameter of 10 to 40 nm are used as the external additive particles, together with hydrophobicα-type alumina fine particles having a number average primary particle diameter of 100 to 600 nm or hydrophobic silica fine particles having a number average primary particle diameter of 100 to 600 nm. The obtained negative charging toner shows excellent charging stability and durability and no unevenness to a printed image. COPYRIGHT: (C)2011,JPO&INPIT
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