Toner

1 . A toner comprising:

a toner particle; and

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

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

in Formula (1), n represents an integer of 1 or more,

where 2.00 g of the silica fine particle is dispersed in a mixed liquid of 25.0 g of ethanol and 75.0 g of a 20 mass % NaCl aqueous solution and a titration operation using a sodium hydroxide (NaOH) solution is performed, Sn defined as Formula (10) satisfies Formula (2),

0.05≤Sn≤0.20  (2)

Sn={( a−b )× c ×NA}/( d×e )  (10)

in Formula (10),

a is a NaOH titer (L) of the NaOH solution required to adjust to 9.0 a pH of the mixed liquid 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 the pH of the mixed liquid 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 the concentration (mol/L) of the NaOH solution,

NA is Avogadro's number,

d is the 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, with D denoting an area of a peak having a peak top present in a range from −25 to −15 ppm, S denoting 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) denoting a specific surface area of the silica fine particle,

the M unit is (R i )(R i )(R k )SiO 1/2   Formula (4),

the D unit is (R g )(R h )Si(O 1/2 ) 2   Formula (5),

the T unit is R m Si(O 1/2 ) 3   Formula (6),

the Q unit is Si(O 1/2 ) 4   Formula (7),

R i , R j , R k , R g , R h , and R m in Formulas (4)-(6) are each an alkyl group, a halogen atom, a hydroxy group, an acetoxy group, or an alkoxy group,

a value (D/S)/B of a ratio of (D/S) relative to B is 5.7×10 −4 to 56×10 −4 ;

(D/S)/B measured after washing of the silica fine particle with chloroform is 1.7×10 −4 to 56×10 −4 ;

with D1 as an area of a peak having a peak top present in a range of more than −19 ppm and −17 ppm or less, in the chemical shift, a value (D1/D) of a ratio of D1 relative to D is 0.10 to 0.30; and

a vinyl-based resin having a structure represented by Formula (9) is present on the surface of the toner particle,

in Formula (9), R 4 is a hydrocarbon group having 1 to 10 carbon atoms.

2 . The toner according to claim 1 , wherein an abundance ratio of the structure represented by Formula (9) on the surface of the toner particle is denoted by Sa (area %), the Sa is 50 area % or more.

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

4 . The toner according to claim 1 , wherein a coverage of the surface of the toner particle by the silica fine particle that is calculated from an image of the toner surface observed by a scanning electron microscope is denoted by Ssi (area %), the Ssi is 30 to 100 area %.

5 . The toner according to claim 1 , wherein

an abundance ratio of the structure represented by Formula (9) on the surface of the toner particle is denoted by Sa (area %), and

a coverage of the surface of the toner particle by the silica fine particle that is calculated from an image of the toner surface observed by a scanning electron microscope is denoted by Ssi (area %),

a value (Sa/Ssi) of the ratio of the Sa to the Ssi is 0.25 to 3.00.

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

in Formula (3), R 1 and R 2 each independently represent a carbinol group, a hydroxy group, an epoxy group, a carboxy group, an alkyl group, or a hydrogen atom, and m is the average number of repeating units and is an integer of from 1 to 200.

7 . The toner according to claim 1 , wherein a carbon amount immobilization rate when the silica fine particle is washed with chloroform is 30 to 70%, and

wherein 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.

8 . The toner according to claim 1 , further comprising a strontium titanate fine particle on the surface of the toner particle.

9 . 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.