| 摘要 |
A toner comprising toner particles which comprise a binder resin and a colorant, and also inorganic fine particles as external additives, wherein the inorganic fine particles are silica fine particles and a group 2 element titanate fine particles, the inorganic fine particles have specific particle diameters, the silica fine particles have a coverage ratio X1 on the surfaces of the toner particles, which is not less than 40.0 surface area % and not more than 75.0 surface area %, when the theoretical coverage ratio by the silica fine particles is X2, the diffusion index defined as “diffusion index=X1/X2” satisfies the condition: diffusion index≧−0.0042×X1+0.62, and the external additives have an embedding ratio on the toner particles, which satisfies a specific range. |
| 主权项 |
1. A toner comprising:
toner particles each comprising a binder resin and a colorant; and as external additives, inorganic fine particles A and inorganic fine particles B, wherein the inorganic fine particles A are group 2 element titanate fine particles, the group 2 element titanate fine particles have a number-average particle diameter (D1) of primary particles thereof, which is not less than 60 nm and not more than 200 nm, the inorganic fine particles B are silica fine particles, the silica fine particles have a number-average particle diameter (D1) of primary particles thereof, which is not less than 5 nm and not more than 20 nm, the silica fine particles have a coverage ratio X1 on surfaces of the toner particles, as determined with an x-ray photoelectron spectrometer (ESCA spectrometer), which is not less than 40.0 surface area % and not more than 75.0 surface area %, when the theoretical coverage ratio by the silica fine particles is X2, a diffusion index defined by Formula 1 below satisfies Formula 2 below:
diffusion index=X1/X2 Formula 1diffusion index≧−0.0042×X1+0.62 Formula 2and
the external additives have an embedding ratio on the toner particles, which is not less than 25% and not more than 60%. |
