Toner

1 . A toner comprising:

a toner particle comprising a binder resin and a release agent; and

a silica fine particle on a surface of the toner particle;

the release agent being present on the surface of the toner particle, wherein

fragment ions corresponding to a structure represented by Formula (1) are observed in a measurement of the silica fine particle by time-of-flight secondary ion mass spectrometry

where n represents an integer of 1 or more;

0.05≤Sn≤0.20 and

Sn={(a−b)×c×NA} /(d×e)

when 2.00 g of the silica fine particle is dispersed in a mixed solution of 25.0 g of ethanol and 75.0 g of a 20 mass % aqueous solution of NaCl, followed by a titration operation using a sodium hydroxide (NaOH) solution,

when a is a NaOH titer (L) of the NaOH solution required to adjust to 9.0 a pH of the mixed solution in which the silica fine particle has been dispersed,

b is a NaOH titer (L) of the NaOH solution required to adjust to 9.0 a pH of the mixed solution of 25.0 g of ethanol and 75.0 g of a 20 mass % aqueous solution of NaCl without the silica fine particle having been dispersed,

c is a concentration (mol/L) of the NaOH solution,

NA is Avogadro's number,

d is a mass (g) of the silica fine particle, and

e is a BET specific surface area (nm 2 /g) of the silica fine particle;

in a chemical shift obtained by solid-state 29 Si—NMR DD/MAS of the silica fine particle, when D is an area of a peak having a peak top present in a range from −25 to −15 ppm, S is the sum total of areas of peaks of an M unit, a D unit, a T unit and a Q unit present in a range from −140 to 100 ppm, and B (m 2 /g) is a specific surface area of the silica fine particle,

the M unit is(R i )(R j )(R k )SiO 1/2

the D unit is(R g )(R h )Si(O 1/2 ) 2

the T unit is R m Si(O 1/2 ) 3

the Q unit is Si(O 1/2 ) 4

where R i , R j R k , R g , R h , and R m are an alkyl group, a halogen atom, a hydroxy group, an acetoxy group or an alkoxy group,

(D/S)/B is 5.7×10 −4 to 4.9×10 −3 and

(D/S)/B measured after washing the silica fine particle with chloroform is 1.7×10 −4 to 4.9×10 −3 ;

(D1/D) is 0.10 to 0.30 when D1 is an area of a peak having a peak top present in a range of more than −19 ppm and −17 ppm or less; and

Sw is 10 to 70 area % when Sw (area %) is an abundance of the release agent on the surface of the toner particle.

2 . The toner according to claim 1 ,

wherein Ssi is 25 to 90 area % when Ssi (area %) is a coverage ratio of the surface of the toner particle by the silica fine particle calculated on the basis of an observation image of the surface of the toner using a scanning electron microscope.

3 . The toner according to claim 1 ,

wherein

(Sw/Ssi) is 0.18 to 2.80 when Ssi (area %) is a coverage ratio of the surface of the toner particle by the silica fine particle calculated on the basis of an observation image of the surface of the toner using a scanning electron microscope.

4 . The toner according to claim 1 , wherein a carbon amount immobilization rate upon washing of the silica fine particle with chloroform is 30 to 70%,

where the carbon amount immobilization rate (%) is (carbon amount in silica fine particle treated with chloroform)/(carbon amount in silica fine particle before washing with chloroform)×100.

5 . The toner according to claim 1 , wherein a content of the silica fine particle is 0.2 to 2.2 parts by mass relative to 100 parts by mass of the toner particle.

6 . The toner according to claim 1 , wherein a number-average particle diameter of primary particle of the silica fine particle is 5 to 50 nm.

7 . The toner according to claim 1 , wherein the silica fine particle is surface-treated with at least a compound represented by Formula (3)

where R 1 and R 2 independently represent a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group or a hydrogen atom, and m is an integer of 1 to 200.

8 . The toner according to claim 1 ,

wherein the toner further comprises a strontium titanate fine particle on the surface of the toner particle; and

a value (Si/Sr) of an element intensity-basis ratio of a content of the silica fine particle relative to a content of the strontium titanate fine particle, on the basis of an X-ray fluorescence analysis of the toner is 0.10 to 1.50.

9 . The toner according to claim 1 , wherein the release agent is at least one member selected from the group consisting of a hydrocarbon wax and an ester wax.

10 . The toner according to claim 1 , wherein a content of the release agent is 0.5 to 15.0 parts by mass relative to 100 parts by mass of the binder resin.

11 . The toner according to claim 1 , wherein the silica fine particle is a silicone-oil-treated product of a silica fine particle treated with a cyclic siloxane.