Toner for electrostatic image development, electrostatic image developer, and toner cartridge

1. A toner for electrostatic image development, comprising:

toner particles;

Si-doped strontium titanate particles; and

silica particles,

wherein a particle diameter D of at least one peak in a number-based particle size distribution of primary particles of the silica particles is larger than a number-based median diameter D 50 of primary particles of the Si-doped strontium titanate particles.

2. The toner for electrostatic image development according to claim 1 ,

wherein a molar amount of Si contained in the Si-doped strontium titanate particles is from 0.25 mol % to 10 mol % inclusive based on a molar amount of Sr contained in the Si-doped strontium titanate particles.

3. The toner for electrostatic image development according to claim 2 ,

wherein the molar amount of Si contained in the Si-doped strontium titanate particles is from 1 mol % to 5 mol % inclusive based on the molar amount of Sr contained in the Si-doped strontium titanate particles.

4. The toner for electrostatic image development according to claim 1 ,

wherein the median diameter D 50 of the Si-doped strontium titanate particles is from 30 nm to 80 nm inclusive.

5. The toner for electrostatic image development according to claim 4 ,

wherein the median diameter D 50 of the Si-doped strontium titanate particles is from 30 nm to 60 nm inclusive.

6. The toner for electrostatic image development according to claim 1 ,

wherein the particle diameter D of the silica particles is from 40 nm to 120 nm inclusive.

7. The toner for electrostatic image development according to claim 6 ,

wherein the particle diameter D of the silica particles is from 60 nm to 110 nm inclusive.

8. The toner for electrostatic image development according to claim 1 ,

wherein the median diameter D 50 of the Si-doped strontium titanate particles and the particle diameter D of the at least one peak in the number-based particle size distribution of the primary particles of the silica particles satisfy a relation represented by 10 nm≤D−D 50 ≤100 nm.

9. The toner for electrostatic image development according to claim 8 ,

wherein the median diameter D 50 of the Si-doped strontium titanate particles and the particle diameter D of the at least one peak in the number-based particle size distribution of the primary particles of the silica particles satisfy a relation represented by 20 nm≤D−D 50 ≤90 nm.

10. The toner for electrostatic image development according to claim 1 ,

wherein the silica particles include sol-gel silica particles, and

wherein the particle diameter D of at least one peak formed by the sol-gel silica particles in the number-based particle size distribution of the primary particles of the silica particles is larger than the number-based median diameter D 50 of the primary particles of the Si-doped strontium titanate particles.

11. The toner for electrostatic image development according to claim 10 ,

wherein the median diameter D 50 of the Si-doped strontium titanate particles and the particle diameter D of the at least one peak formed by the sol-gel silica particles satisfy a relation represented by 10 nm≤D−D 50 ≤100 nm.

12. The toner for electrostatic image development according to claim 10 ,

wherein a water content of the sol-gel silica particles is from 1% by mass to 10% by mass inclusive.

13. The toner for electrostatic image development according to claim 1 ,

wherein a content M1 of the Si-doped strontium titanate particles and a content M2 of silica particles having an average diameter larger than the median diameter D 50 of the Si-doped strontium titanate particles satisfy a relation represented by 1.2≤M2/M1≤5.0 based on mass.

14. An electrostatic image developer comprising the toner for electrostatic image development according to claim 1 .

15. A toner cartridge containing the toner for electrostatic image development according to claim 1 , the toner cartridge being detachably attached to an image forming apparatus.