Magnetic toner and image forming method

• US 6,653,036 B1
• Filed: 09/16/1998
• Issued: 11/25/2003
• Est. Priority Date: 09/16/1997
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Kobori, Takakuni, Fujimoto, Masami, Fujikawa, Hiroyuki, Tanikawa, Hirohide
• Primary Examiner(s): RODEE, CHRISTOPHER D
• Application Number:
  US09/153,898
• Time in Patent Office: 1,896 Days
• Field of Search: 430/106.6, 430/106.1, 430/106.2, 430/120, 430/132, 430/137.1
• US Class Current: 430/106.2
• CPC Class Codes: G03G 9/0833 Oxides
• CPC Class Codes: G03G 9/0834 Non-magnetic inorganic compounds chemically incorporated in magnetic components
• CPC Class Codes: G03G 9/0837 Structural characteristics of the magnetic components, e.g. shape, crystallographic structure

Abstract

A magnetic toner includes a magnetic toner particle containing a binding resin and a magnetic material. The magnetic material includes a magnetic iron oxide containing 0.10% to 4.00% by weight of an element α belonging to the third period to the seventh period with an atomic number of 11 to 103 and having an electronegativity of 1.0 to 2.5. The solubility S₁ of α in the magnetic material at an iron solubility of 0% to 20% is from 10% to less than 44% and the solubility S₂ of α at an iron solubility of 80% to 100% is from 5% to less than 30%. The magnetic material contains at least 60% by number of multinuclear magnetic iron oxide particles or at least 60% by number of polyhedral magnetic iron oxide particles having faces at ridgeline portions of hexahedron and/or octahedron multinuclear magnetic iron oxide particles.

Claims

1. A magnetic toner comprising a magnetic toner particle containing at least a binding resin and a magnetic material;

wherein the magnetic material comprises a magnetic iron oxide and contains 0.10% to 4.00% by weight of an element α

from the third period to the seventh period with an atomic number of 11 to 103 in the long-period Periodic Table and having an electronegativity of 0.1 to 2.5;

the solubility S₁ of the element α

in said magnetic material at an iron solubility of 0% to 20% lies in a range from 10% to less than 44%, the solubility S₂ of the element α

in said magnetic material at an iron solubility of 80% to 100% lies in a range from 5% to less than 30%; and

said magnetic material is selected from the group consisting of

(i) a magnetic material containing at least 60% by number of multinuclear magnetic iron oxide particles based on magnetic iron oxide particles,

(ii) a magnetic material containing at least 50% by number based on magnetic iron oxide particles of multinuclear magnetic iron oxide particles and at least 60% by number in total, based on magnetic iron oxide particles, of polyhedral magnetic iron oxide particles having faces at ridgeline portion of hexahedron and multinuclear magnetic iron oxide particles,

(iii) magnetic material containing at least 50% by number based on magnetic iron oxide particles of multinuclear magnetic iron oxide particles and at least 60% by number in total, based on magnetic iron oxide particles, of polyhedral magnetic iron oxide particles having faces at ridgeline portion of octahedron and multinuclear magnetic iron oxide particles, and

(iv) magnetic material containing at least 50% by number based on magnetic iron oxide particles of multinuclear magnetic iron oxide particles and at least 60% by number in total, based on magnetic iron oxide particles, of polyhedral magnetic iron oxide particles having faces at ridgeline portion of hexahedron, polyhedral magnetic iron oxide particles having faces at ridgeline portion of octahedron and multinuclear magnetic iron oxide particles.

2. The magnetic toner according to claim 1, wherein the solubility S₁ and the solubility S₂ satisfy the relationship S₁≧

S₂.

3. The magnetic toner according to claim 1, wherein the solubility S₃ of the element α

is 10% to less than 25%.

4. The magnetic toner according to claim 3, wherein the solubility S₁, the solubility S₂ and the solubility S₃ satisfy the relationships S₁>

S₂, S₁≧

S₃, and S₃≧

S₂.

5. The magnetic toner according to claim 1, wherein said magnetic material contains 0.15% to 3.00% by weight of the element α

, the solubility S₁ is 15% to less than 42%, and the solubility S₂ is 5% to less than 25%.

6. The magnetic toner according to claim 1, wherein said magnetic material contains 0.20% to 2.50% by weight of the element α

, the solubility S₁ is 20% to less than 40%, and the solubility S₂ is 10% to less than 20%.

7. The magnetic toner according to claim 1, wherein said magnetic material has a number-average particle diameter of 0.05 to 0.50 μ

m.

8. The magnetic toner according to claim 1, wherein the element α

is selected from the group consisting of Si, Al, P, V, Cr, Co, Ni, Cu, Zn, Ga, Ge, Zr, Sn and Pb.

9. The magnetic toner according to claim 1, wherein the element α

is selected from the group consisting of Si, Al and P.

10. The magnetic toner according to claim 1, wherein the element α

is Si.

11. The magnetic toner according to claim 1, wherein said magnetic toner has a weight-average particle diameter of 3.0 to 9.0 μ

m.

12. The magnetic toner according to claim 1, wherein said magnetic material is contained in an amount of 20 to 200 parts by weight to 100 parts of said binding resin.

13. The magnetic toner according to claim 1, wherein said magnetic material is contained in an amount of 40 to 150 parts by weight to 100 parts of said binding resin.

14. The magnetic toner according to claim 1, wherein said magnetic material is contained in an amount of 50 to 120 parts by weight to 100 parts of said binding resin.

15. The magnetic toner according to claim 1, which has positively charging characteristics.

16. The magnetic toner according to claim 1, wherein the element α

belongs to the third, fourth or fifth period in the long-period Periodic Table.

17. An image forming method comprising a step of forming an electrostatic image on a latent image carrier and a step of developing the electrostatic image with a magnetic toner to form a magnetic toner image;

wherein

said magnetic toner comprises a magnetic toner particle containing at least a binding resin and a magnetic material;

wherein

said magnetic material comprises a magnetic iron oxide and contains 0.10% to 4.00% by weight of an element α

from the third period to the seventh period with an atomic number from 11 to 103 in the long period Periodic Table and having an electronegatively of 0.1 to 2.5;

the solubility S₁ of the element α

in said magnetic material at an iron solubility of 0% to 20% lies in a range from 10% to less than 44%, the solubility S₂ of the element α

in the magnetic material at an iron solubility of 80% to 100% lies in a range from 5% to less than 30%; and

the magnetic material is selected from the group consisting of

(i) a magnetic material containing at least 60% by number of multinuclear magnetic iron oxide particles based on magnetic iron oxide particles,

(ii) a magnetic material containing at least 50% by number based on magnetic iron oxide particles of multinuclear magnetic iron oxide particles and at least 60% by number in total, based on magnetic iron oxide particles, of polyhedral magnetic iron oxide particles having faces at ridgeline portion of hexahedron and multinuclear magnetic iron oxide particles,

(iii) magnetic material containing at least 50% by number based on magnetic iron oxide particles of multinuclear magnetic iron oxide particles and at least 60% by number in total, based on magnetic iron oxide particles, of polyhedral magnetic iron oxide particles having faces at ridgeline portion of octahedron and multinuclear magnetic iron oxide particles, and

(iv) magnetic material containing at least 50% by number based on magnetic iron oxide particles of multinuclear magnetic iron oxide particles and at least 60% by number in total, based on magnetic iron oxide particles, of polyhedral magnetic iron oxide particles having faces at ridgeline portion of hexahedron, polyhedral magnetic iron oxide particles having faces at ridgeline portion of octahedron and multinuclear magnetic iron oxide particles.

18. The image forming method according to claim 17, wherein said magnetic toner has positively charging characteristics.

19. The image forming method according to claim 17, wherein said latent image carrier is an amorphous silicon photosensitive drum.

20. The image forming method according to claim 19, wherein the amorphous silicon photosensitive drum is positively charged to form an electrostatic image, and then the electrostatic image is reversely developed with a positively charging magnetic toner.

21. The image forming method according to claim 17, wherein the solubility S₁ and the solubility S₂ satisfy the relationship S₁≧

S₂.

22. The image forming method according to claim 17, wherein the solubility S₃ of the element α

is from 10% to less than 25%.

23. The image forming method according to claim 17, wherein the solubility S₁, the solubility S₂ and the solubility S₃ satisfy the relationships S₁>

S₂, S₁≧

S₃, and S₃≧

S₂.

24. The image forming method according to claim 17, wherein said magnetic material contains 0.15% to 3.00% by weight of the element α

, the solubility S₁ is 15% to less than 42%, and the solubility S₂ is 5% to less than 25%.

25. The image forming method according to claim 17, wherein said magnetic material contains 0.20% to 2.50% by weight of the element α

, the solubility S₁ is 20% to less than 40%, and the solubility S₂ is 10% to less than 20%.

26. The image forming method according to claim 17, wherein said magnetic material has a number-average particle diameter of 0.05 to 0.50 μ

m.

27. The image forming method according to claim 17, wherein the element α

is selected from the group consisting of Si, Al, P, V, Cr, Co, Ni, Cu, Zn, Ga, Ge, Zr, Sn and Pb.

28. The image forming method according to claim 17, wherein the element α

is selected from the group consisting of Si, Al and P.

29. The image forming method according to claim 17, wherein the element α

is Si.

30. The image forming method according to claim 17, wherein said magnetic toner has a weight-average particle diameter of 3.0 to 9.0 μ

m.

31. The image forming method according to claim 17, wherein said magnetic material is contained in an amount of 20 to 200 parts by weight to 100 parts of said binding resin.

32. The image forming method according to claim 17, wherein said magnetic material is contained in an amount of 40 to 150 parts by weight to 100 parts of said binding resin.

33. The image forming method according to claim 17, wherein said magnetic material is contained in an amount of 50 to 120 parts by weight to 100 parts of said binding resin.

34. The image forming method according to claim 17, wherein the element α

belongs to the third, fourth or fifth period in the long-period Periodic Table.