| 摘要 |
PROBLEM TO BE SOLVED: To provide a negatively charged toner excellent in charge stability in printing on a large number of sheets and so excellent in durability as not to cause unevenness to printed images, which is a negatively charged toner comprising toner base particles obtained by adding an aqueous medium to a solution prepared by dispersing/dissolving a colorant, a wax component and an anionic self-water-dispersive polyester resin in a hydrophobic solvent, and carrying out phase inversion emulsification. SOLUTION: The negatively charged toner is obtained by externally adding external additive particles hydrophobed with a silane coupling agent to the toner base particles obtained by phase inversion emulsification, wherein hydrophobicα-alumina fine particles having a number average primary particle diameter of 100-600 nm and/or hydrophobic silica fine particles having a number average primary particle diameter of 100-600 nm are used as the external additive particles in combination with hydrophobic silica fine particles having a number average primary particle diameter of 7-60 nm and hydrophobic titanium oxide fine particles having a number average primary particle diameter of 10-40 nm. COPYRIGHT: (C)2007,JPO&INPIT
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