Anisotropic magnetic material-dispersed resin carrier, electrophotographic developer, and developing device

1. An anisotropic magnetic material-dispersed resin carrier, comprising:

fine magnetic particles; and

a binder resin in which at least the fine magnetic particles are dispersed,

wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the fine magnetic particles are orientated in a same direction, and

wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 μm or more but less than 100 μm.

2. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein a ratio by mass of the binder resin to the fine magnetic particles is 65/35 to 80/20.

3. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein the anisotropic magnetic material-dispersed resin carrier has an average circularity of 0.85 to 0.94.

4. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein the fine magnetic particles are a rare earth magnetic powder containing a rare earth, iron, and nitrogen as elements.

5. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein the fine magnetic particles are SmFeN.

6. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein the carrier is obtained by a method containing melt-kneading the fine magnetic particles in the binder resin to prepare a molded product, and leaving the molded product in a magnetic flux density of 2T or more for 10 sec or longer.

7. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein the fine magnetic particles comprise a rare earth magnetic powder.

8. The anisotropic magnetic material-dispersed resin carrier according to claim 7 , wherein the rare earth powder contains a rare earth element in an amount of 5 at. % to 40 at. %.

9. The anisotropic magnetic material-dispersed resin carrier according to claim 1 , wherein the fine magnetic particles have a number average particle diameter of 0.5 μm or more but less than 8 μm.

10. An electrophotographic developer comprising:

an anisotropic magnetic material-dispersed resin carrier which contains:

magnetic particles; and

a binder resin in which at least the magnetic particles are dispersed,

wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the magnetic particles are orientated in a same direction, and

wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force 20 of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 μm or more but less than 100 μm.

11. The electrophotographic developer according to claim 10 , wherein the magnetic particles comprise a rare earth magnetic powder.

12. A developing device comprising:

an electrophotographic developer which contains an anisotropic magnetic material-dispersed resin carrier,

wherein the anisotropic magnetic material-dispersed resin carrier contains:

magnetic particles; and

a binder resin in which at least the magnetic particles are dispersed,

wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the magnetic particles are orientated in a same direction, and

wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 μm or more but less than 100 μm.

13. The developing device according to claim 12 , wherein the magnetic particles comprise a rare earth magnetic powder.