External additive for toner, and toner
An external additive for a toner comprising a silica particle surface-treated with a polyhydric acid metal salt particle, wherein the polyhydric acid metal salt particle is particle of a salt of a polyhydric acid and a titanium compound, and a toner comprising a toner particle, and an external additive for a toner on the surface of the toner particle, wherein the external additive for a toner is the above external additive for a toner.
1 . An external additive for a toner, comprising:
a silica particle surface-treated with a polyhydric acid metal salt particle, wherein
the polyhydric acid metal salt particle is a particle of a titanium phosphate compound or a titanium carbonate compound, and
the external additive has a relative dielectric constant of 2.10 to 2.20 at the frequency at which a dielectric loss tangent tan δ is minimum in a sweep frequency range of 1 MHz to 0.01 Hz.
2 . The external additive for a toner according to claim 1 , wherein the polyhydric acid metal salt particle is present in the silica particle at a content of 0.01 to 1.00 mass %.
3 . The external additive for a toner according to claim 1 , wherein the polyhydric acid is phosphoric acid.
4 . The external additive for a toner according to claim 1 , wherein the silica particle has a number-average particle diameter of 10 to 500 nm.
5 . The external additive for a toner according to claim 1 ,
wherein the silica particle is sol-gel silica particle.
6 . A toner, comprising:
a toner particle; and
an external additive on the surface of the toner particle, wherein
the external additive is the external additive for a toner according to claim 1 .