Electrostatic-image developing toner, electrostatic-image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

1. An electrostatic-image developing toner comprising:

toner particles;

aggregated silica particles A treated with an oil; and

aggregated or non-aggregated silica particles B rendered hydrophobic with a hydrophobizing agent other than an oil,

wherein an average particle size Da of the aggregated silica particles A and an average particle size Db of the silica particles B satisfy Da≥Db, and

wherein the electrostatic-image developing toner does not include any external additive other than the aggregated silica particles A or the silica particles B.

2. The electrostatic-image developing toner according to claim 1 ,

wherein a ratio Da/Db of the average particle size Da to the average particle size Db is 1.0 or more and 2.0 or less.

3. The electrostatic-image developing toner according to claim 1 ,

wherein a mass ratio Ma/Mb of a content Ma of the aggregated silica particles A to a content Mb of the silica particles B is 0.5 or more and 1.0 or less.

4. The electrostatic-image developing toner according to claim 1 ,

wherein the silica particles B include non-aggregated particles that are wet-process silica particles.

5. The electrostatic-image developing toner according to claim 1 ,

wherein the silica particles B include silica particles rendered hydrophobic with 1, 1, 1, 3, 3, 3-hexamethyldisilazane.

6. The electrostatic-image developing toner according to claim 1 ,

wherein the aggregated silica particles A include aggregated particles that are gas-phase method silica particles.

7. The electrostatic-image developing toner according to claim 1 ,

wherein the aggregated silica particles A include aggregated silica particles treated with a silicone oil.

8. The electrostatic-image developing toner according to claim 1 ,

wherein a particle-size number frequency distribution of the aggregated silica particles A has first and second peaks,

the first peak occurs at a particle size of 80 nm or more and 110 nm or less, and

the second peak occurs at a particle size of 50 nm or more and 80 nm or less.

9. The electrostatic-image developing toner according to claim 1 ,

wherein the average particle size Da is 70 nm or more and 110 nm or less.

10. The electrostatic-image developing toner according to claim 1 ,

wherein the average particle size Db is 20 nm or more and 80 nm or less.

11. The electrostatic-image developing toner according to claim 1 ,

wherein a coverage of the aggregated silica particles A on surfaces of the toner particles is 5% or more and 30% or less.

12. The electrostatic-image developing toner according to claim 1 ,

wherein a coverage of all the external additives on surfaces of the toner particles is 60% or more and 100% or less.

13. The electrostatic-image developing toner according to claim 1 ,

wherein, in a particle-size number frequency distribution of all the external additives, 75% or more of all the external additives have a particle size of 20 nm or more and 100 nm or less.

14. The electrostatic-image developing toner according to claim 1 , further comprising tetrakis (trimethylsiloxy) silane.

15. The electrostatic-image developing toner according to claim 14 ,

wherein a content of the tetrakis (trimethylsiloxy) silane is 0.01 ppm by mass or more and 10 ppm by mass or less.

16. An electrostatic-image developer comprising the electrostatic-image developing toner according to claim 1 .

17. A toner cartridge detachably attachable to an image forming apparatus,

the toner cartridge comprising the electrostatic-image developing toner according to claim 1 .

18. The toner cartridge according to claim 17 , that is a rotary toner cartridge that includes a rotatable main body that accommodates the electrostatic-image developing toner.

19. A process cartridge detachably attachable to an image forming apparatus,

the process cartridge comprising:

a developing unit that includes an electrostatic-image developer and develops an electrostatic image formed on a surface of an image holding member with the electrostatic-image developer to form a toner image;

a toner cartridge that includes the electrostatic-image developing toner according to claim 1 ; and

a toner supply line that connects the toner cartridge to the developing unit and feeds the electrostatic-image developing toner included in the toner cartridge into the developing unit.

20. An image forming apparatus comprising:

an image holding member;

a charging unit that charges a surface of the image holding member;

an electrostatic-image formation unit that forms an electrostatic image on the charged surface of the image holding member;

a developing unit that includes an electrostatic-image developer and develops the electrostatic image formed on the surface of the image holding member with the electrostatic-image developer to form a toner image;

a transfer unit that transfers the toner image formed on the surface of the image holding member onto a surface of a recording medium;

a fixing unit that fixes the toner image transferred on the surface of the recording medium;

a replacement toner accommodating unit that includes the electrostatic-image developing toner according to claim 1 ; and

a toner supply line that connects the replacement toner accommodating unit to the developing unit and feeds the electrostatic-image developing toner included in the replacement toner accommodating unit into the developing unit.

21. An image forming method comprising:

charging a surface of an image holding member;

forming an electrostatic image on the charged surface of the image holding member;

developing the electrostatic image formed on the surface of the image holding member with an electrostatic-image developer to form a toner image;

transferring the toner image formed on the surface of the image holding member onto a surface of a recording medium;

fixing the toner image transferred on the surface of the recording medium; and

feeding the electrostatic-image developing toner according to claim 1 included in a replacement toner accommodating unit from the replacement toner accommodating unit into a developing unit through a toner supply line that connects the replacement toner accommodating unit to the developing unit.