TONER, AND IMAGE FORMING METHOD AND APPARATUS AND PROCESS CARTRIDGE USING THE TONER

Abstract

A toner including toner particles including a binder resin, a colorant and a release agent, and an external additive including a first particulate inorganic material having a formula of MgxSiyOx+2y where each of x and y is an integer, and a number average secondary particle diameter of from 0.02 μm to 2 μm, wherein the first atomic ratio (Mg/Si) s in a surface portion of the first particulate inorganic material is not greater than (preferably less than) the second atomic ratio (Mg/Si)e in the entire first particulate inorganic material. Alternatively, a toner including toner particles including a binder resin and a colorant, and an external additive which includes a particulate inorganic material having a formula of MgxSiyOx+2y where each of x and y is an integer and which has a surface treated with a fatty acid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an example of the image forming apparatus of the present invention;

FIG. 2 is a schematic view illustrating a charging device and an image bearing member for use in an example of the image forming apparatus of the present invention; and

FIG. 3 is a schematic view illustrating a developing device and an image bearing member for use in an example of the image forming apparatus of the present invention.

Claims

1. A toner comprising: toner particles comprising: a binder resin;a colorant; anda release agent, andan external additive comprising a first particulate inorganic material having a formula of MgxSiyOx+2y where each of x and y is an integer, and a number average secondary particle diameter of from 0.02 μm to 2 μm, wherein a first atomic ratio (Mg/Si) s in a surface portion of the first particulate inorganic material is not greater than a second atomic ratio (Mg/Si)e in the entire first particulate inorganic material.

2. The toner according to claim 1, wherein the first atomic ratio (Mg/Si)s in a surface portion of the first particulate inorganic material is less than the second atomic ratio (Mg/Si) e in the entire first particulate inorganic material.

3. The toner according to claim 2, wherein the first particulate inorganic material has a number average primary particle diameter of from 0.02 μm to 0.15 μm.

4. The toner according to claim 2, wherein the first particulate inorganic material includes sintered aggregates of MgxSiyOx+2y having a number average secondary particle diameter of from 0.05 μm to 2 μm.

5. The toner according to claim 2, wherein the first particulate inorganic material includes at least one member selected from the group consisting of forsterite, enstatite and steatite.

6. The toner according to claim 2, wherein the first inorganic material is prepared by a method comprising: sintering a Mg(OH)2 powder or a MgO powder together with a SiO2 powder having a number average primary particle diameter of not greater than 0.10 μm; andsubjecting the sintered material to a surface treatment to control the second atomic ratio (Mg/Si) s in a surface portion of the particulate inorganic material.

7. The toner according to claim 2, wherein the external additive further comprises: a second particulate inorganic material including a particulate hydrophobic silica having a number average primary particle diameter of from 5 nm to 20 nm; anda third particulate inorganic material including a member selected from the group consisting of particulate hydrophobic titania, particulate hydrophobic silica, and a combination thereof, all of which have a number average primary particle diameter of from 20 nm to 100 nm.

8. The toner according to claim 7, wherein the first particulate inorganic material is included in the toner in an amount of from 0.3% to 5% by weight based on a weight of the toner particles, and the second and third particulate inorganic materials are included in the toner in a total amount of from 2% to 5% by weight based on the weight of the toner particles.

9. The toner according to claim 7, wherein a weight ratio (B/C) of the second particulate inorganic material (B) to the third particulate inorganic material (C) is from 1/9 to 7/3.

10. The toner according to claim 1, wherein the external additive further comprises: a second particulate inorganic material including a particulate hydrophobic silica having a number average primary particle diameter of from 5 nm to 20 nm; anda third particulate inorganic material including a member selected from the group consisting of particulate hydrophobic titania, particulate hydrophobic silica, and a combination thereof, all of which have a number average primary particle diameter of from 20 nm to 100 nm.

11. The toner according to claim 10, wherein the first particulate inorganic material has a number average primary particle diameter of from 0.01 μm to 0.5 μm.

12. The toner according to claim 10, wherein each of the second particulate inorganic material and the third particulate inorganic material has a hydrophobicity of from 50 to 90.

13. The toner according to claim 10, wherein the first particulate inorganic material has a molar ratio (MgO)/(SiO2) of from 0.8 to 2.2.

14. The toner according to claim 1, wherein the toner particles have a volume average particle diameter of from 4 μm to 9 μm.

15. The toner according to claim 1, wherein the release agent is included in the toner particles in an amount of from 3.5 to 10% by weight based on a total weight of the toner particles when the toner particles are prepared by a pulverization method.

16. The toner according to claim 1, wherein the release agent is included in the toner particles in an amount of from 5 to 12% by weight based on a total weight of the toner particles when the toner particles are prepared by a wet granulation method.

17. A toner comprising: toner particles comprising: a binder resin; anda colorant, andan external additive which comprises a particulate inorganic material having a formula of MgxSiyOx+2y where each of x and y is an integer and which has a surface treated with a fatty acid.

18. The toner according to claim 17, wherein the fatty acid has a formula of CnH2n+1COOH where n is an integer of from 10 to 25.

19. The toner according to claim 17, wherein the particulate inorganic material has an average primary particle diameter of from 0.05 to 0.15 μm and an average secondary particle diameter of from 0.2 to 0.6 μm, and is included in the toner in an amount of from 0.05 to 2 parts by weight based on 100 parts by weight of the toner particles.

20. The toner according to claim 17, wherein the particulate inorganic material includes at least one member selected from the group consisting of forsterite, enstatite and steatite.

21. An image forming apparatus comprising: an image bearing member configured to bear an electrostatic latent image thereon;a latent image forming device configured to form the electrostatic latent image on the image bearing member and including a charger; anda developing device configured to develop the electrostatic latent image with a developer including the toner according to claim 1 to form a toner image on the image bearing member.

22. An image forming apparatus comprising: an image bearing member configured to bear an electrostatic latent image thereon;a latent image forming device configured to form the electrostatic latent image on the image bearing member and including a charger; anda developing device configured to develop the electrostatic latent image with a developer including the toner according to claim 17 to form a toner image on the image bearing member.

23. A process cartridge comprising: an image bearing member configured to bear an electrostatic latent image thereon; anda developing device configured to develop the electrostatic latent image with a developer including the toner according to claim 1 to form a toner image on the image bearing member,wherein the process cartridge can be detachably set in an image forming apparatus.

24. A process cartridge comprising: an image bearing member configured to bear an electrostatic latent image thereon; anda developing device configured to develop the electrostatic latent image with a developer including the toner according to claim 17 to form a toner image on the image bearing member,wherein the process cartridge can be detachably set in an image forming apparatus.

25. An image forming method comprising: forming an electrostatic latent image on an image bearing member; anddeveloping the electrostatic latent image with a developer including the toner according to claim 1 to form a toner image on the image bearing member.

26. An image forming method comprising: forming an electrostatic latent image on an image bearing member; anddeveloping the electrostatic latent image with a developer including the toner according to claim 17 to form a toner image on the image bearing member.