JP2015125302A5 - - Google Patents

Claims (4)

Toner particles containing a binder resin and a colorant;
Titanium oxide fine particles and silica fine particles as external additives,
A toner having
The titanium oxide fine particles are:
The major axis diameter is 30 nm or more and 500 nm or less,
The minor axis diameter is 10 nm or more and 80 nm or less,
Rutile-type titanium oxide fine particles having a major axis diameter / minor axis diameter ratio of 2.0 or more and 8.0 or less,
The titanium oxide fine particle content is 0.1 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the toner particles,
The ratio of the content of the silica fine particles to the content of the titanium oxide fine particles in the toner is 0.4 or more and 30.0 or less,
The coverage X1 with the silica fine particles on the surface of the toner particles determined by an X-ray photoelectron spectrometer (ESCA) is 40.0 area% or more and 75.0 area% or less,
When the theoretical coverage by the silica fine particles is X2, the diffusion index represented by the following formula 1 satisfies the following formula 2,
The toner according to claim 1, wherein an embedding rate of the external additive in the toner particles is 25% or more and 60% or less.
(Formula 1) Diffusion index = X1 / X2
(Expression 2) Diffusion index ≧ −0.0042 × X1 + 0.62   The toner according to claim 1, wherein the toner particles have an average circularity of 0.960 or more.   The toner according to claim 1, wherein a liberation rate of the titanium oxide fine particles is 50% or less. The toner according to claim 1, wherein an apparent density of the silica fine particles is 15 g / L or more and 50 g / L or less.