Magnetic composite particles for black magnetic toner and black magnetic toner using the same

Black magnetic toner comprising:

• a binder resin, and
• magnetic composite particles having an average particle diameter of 0.06 to 1.0 μm and a coercive force value of less than 39.790 kA/m, comprising:
• magnetic core particles,
• a coating formed on surface of said magnetic core particles, comprising at least one organosilicon compound selected from the group consisting of:
• (1) organosilane compounds obtainable from alkoxysilane compounds, and
• (2) polysiloxanes or modified polysiloxanes, and
• an organic blue-based pigment coat formed on said coating layer comprising said organosilicon compound, in an amount of from 1 to 50 parts by weight based on 100 parts by weight of said magnetic core particles.

Magnetic composite particles comprising:

• magnetic core particles,
• a coating formed on surface of said magnetic core particles, comprising at least one organosilicon compound selected from the group consisting of:
• (1) organosilane compounds obtainable from alkoxysilane compounds, and
• (2) polysiloxanes or modified polysiloxanes, and
• an organic blue-based pigment coat formed on said coating layer comprising said organosilicon compound, in an amount of from 1 to 50 parts by weight based on 100 parts by weight of said magnetic core particles;
• and
• having an average particle diameter of 0.06 to 1.0 μm, a BET specific surface area value of 1.0 to 100 m2/g, a geometrical standard deviation of the particle size of 1.01 to 2.0, a L* value of 2.0 to 13.5, an a* value of −2.0 to 0.0, a b* value of −3.0 to 5.5, and a coercive force value of less than 39.790 kA/m.

Black magnetic toner comprising:

• a binder resin, and
• magnetic composite particles having an average particle diameter of 0.06 to 1.0 μm and a coercive force value of less than 39.790 kA/m, comprising:
• magnetic core particles,
• a coating formed on surface of said magnetic core particles, comprising at least one organosilicon compound selected from the group consisting of:
• (1) organosilane compounds obtainable from alkoxysilane compounds, and
• (2) polysiloxanes or modified polysiloxanes, and
• an organic blue-based pigment coat formed on said coating layer comprising said organosilicon compound, in an amount of from 1 to 50 parts by weight based on 100 parts by weight of said magnetic core particles;
• and
• having an average particle size of 3 to 15 μm, a flowability index of 70 to 100, a volume resistivity of not less than 1.0×1013 Ω·cm, a blackness (L* value) of 2.0 to 13.5, an a* value of −2.0 to 0.0, a b* value of −3.0 to 5.5, a light resistance (ΔE* value) of not more than 5.0, and a coercive force value of less than 39.790 kA/m.