Toner
A toner including a toner particle and an external additive, wherein the external additive contains an inorganic fine particle A and a silica fine particle; in a surface of the toner observed using a scanning electron microscope, a number-average particle diameter of primary particle of the silica fine particle is from 5 nm to 50 nm, a number-average particle diameter of primary particle of the inorganic fine particle A is at least 10 nm and less than 60 nm, a coverage ratio X1 of the toner surface covered by the silica fine particle is from 60 area % to 95 area %, the inorganic fine particle A is a fine particle of a titanate having a Group 2 element, and a coverage ratio X2 of the toner surface covered by the inorganic fine particle A is from 5 area % to 40 area %.
1. A toner, comprising:
a toner particle; and
an external additive comprising an inorganic fine particle A and a silica fine particle, the inorganic fine particle A being a strontium titanate fine particle having a peak at in a range of 39.700°±0.150° and a peak at in a range of 46.200°±0.150° in a CuKα x-ray diffraction spectrum obtained in a range of 2θ of from 10° to 90°, where θ is a Bragg angle, wherein
in a surface of the toner observed using a scanning electron microscope (i) a number-average particle diameter of primary particle of the silica fine particle is 5 to 50 nm, and (ii) a number-average particle diameter of primary particle of the inorganic fine particle A is 10 to less than 60 nm,
a coverage ratio X1 of the toner surface covered by the silica fine particle is 60 to 95 area % as determined using an x-ray photoelectron spectrometer, and
a coverage ratio X2 of the toner surface covered by the inorganic fine particle A is 5 to 40 area % as determined using an x-ray photoelectron spectrometer.
2. The toner according to claim 1 , wherein a fixing ratio of the inorganic fine particle A to the toner particle is from 40 to 100%, the fixing ratio being calculated by (intensity of element Sr of post water-wash toner)/(intensity of element Sr of pre water-wash toner)×100.
3. The toner according to claim 1 , wherein a content of the inorganic fine particle A is 0.5 to 3.5 mass parts per 100 mass parts of the toner particle.
4. The toner according to claim 1 , wherein an average circularity of primary particle of the inorganic fine particle A is from 0.700 to 0.920.
5. The toner according to claim 1 , wherein a methanol concentration at a 50% transmittance of light having a wavelength of 780 nm is 60 to 95 volume % in a test of wettability of the inorganic fine particle A relative to a methanol/water mixed solvent.
6. The toner according to claim 1 , wherein a number-average particle diameter of primary particle of the inorganic fine particle A in a surface of the toner is 10 to 50 nm observed using a scanning electron microscope.
7. The toner according to claim 1 , wherein a Sr/Ti molar ratio for the strontium titanate fine particle is 0.70 to 0.95.
8. A toner, comprising:
a toner particle; and
an external additive comprising an inorganic fine particle A and a silica fine particle, the inorganic fine particle A being a fine particle of a titanate having a Group 2 element, wherein
in a surface of the toner observed using a scanning electron microscope (i) a number-average particle diameter of primary particle of the silica fine particle is 5 to 50 nm, and (ii) a number-average particle diameter of primary particle of the inorganic fine particle A is 10 to less than 60 nm,
a coverage ratio X1 of the toner surface covered by the silica fine particle is 60 to 95 area % as determined using an x-ray photoelectron spectrometer,
a coverage ratio X2 of the toner surface covered by the inorganic fine particle A is 5 to 40 area % as determined using an x-ray photoelectron spectrometer, and
a content of the inorganic fine particle A is 0.5 to 3.5 mass parts per 100 mass parts of the toner particle.
9. A toner, comprising:
a toner particle; and
an external additive comprising an inorganic fine particle A and a silica fine particle, the inorganic fine particle A being a fine particle of a titanate having a Group 2 element, wherein
in a surface of the toner observed using a scanning electron microscope (i) a number-average particle diameter of primary particle of the silica fine particle is 5 to 50 nm, and (ii) a number-average particle diameter of primary particle of the inorganic fine particle A is 10 to less than 60 nm,
a coverage ratio X1 of the toner surface covered by the silica fine particle is 60 to 95 area % as determined using an x-ray photoelectron spectrometer,
a coverage ratio X2 of the toner surface covered by the inorganic fine particle A is 5 to 40 area % as determined using an x-ray photoelectron spectrometer, and
an average circularity of primary particle of the inorganic fine particle A is from 0.700 to 0.920.