A toner comprising a toner particle comprising a binder resin, a nonmagnetic inorganic oxide particle A, and a magnetic iron oxide particle B, wherein a softening point of a chloroform-soluble component of the toner particle is not greater than 90° C.; the nonmagnetic inorganic oxide particle A and the magnetic iron oxide particle B are internally added to the toner particle; the nonmagnetic inorganic oxide particle A comprises as its main component at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; a proportion of the inorganic oxide particles having a long diameter of specific length is in specific range; and a value of a ratio of a number-average particle diameter of the long diameter for the nonmagnetic inorganic oxide particle A, to a number-average particle diameter of the long diameter for the magnetic iron oxide particle B, is 5 to 30.

Provided are a magnetic core material for electrophotographic developer and a carrier for electrophotographic developer, which are excellent in charge characteristics and strength and with which a satisfactory image free from defects can be obtained, and a developer containing the carrier. A magnetic core material for electrophotographic developer, having a sulfur component content of from 50 to 700 ppm in terms of a sulfate ion and a BET specific surface area of from 0.06 to 0.25 m.sup.2/g.

A toner comprising a toner particle comprising a magnetic body, and a silica fine particle on a surface of the toner particle, wherein fragment ions corresponding to a D unit structure are observed in a specific measurement; when the silica fine particle is dispersed in a mixed solution of ethanol and aqueous solution of NaCl, followed by a titration operation using sodium hydroxide, a titer is within a specific range; in a chemical shift obtained by a specific measurement, with D as an area of a peak having a peak top present in a range from 25 to 15 ppm, and with D1 as an area of a peak having a peak top present in a range of more than 19 ppm and 17 ppm or less, D and D1 are in a specific ratio; and the magnetic body is present on the surface of the toner particle.

A magnetic toner comprising a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein a storage elastic modulus E(40) [Pa] at 40 C. and a storage elastic modulus E(85) [Pa] at 85 C., which are obtained in a powder dynamic viscoelasticity measurement of the magnetic toner, satisfy the following formulas (1) to (3).
E(40)6.010.sup.9(1)
E(85)5.510.sup.9(2)
[E(40)E(85)]100/E(40)40(3)

A magnetic toner comprising a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein the dielectric loss tangent at 100 kHz is 1.010.sup.2 or more, a variation coefficient CV3 of an occupied area ratio of the magnetic body when a cross section of the magnetic toner particle is divided by a square grid having a side of 0.8 m in cross-sectional observation of the magnetic toner particle using a transmission electron microscope TEM is from 30.0% to 80.0%, and where a storage elastic modulus of the magnetic toner at 40 C. is taken as E(40) [Pa] and a storage elastic modulus of the magnetic toner at 85 C. is taken as E(85) [Pa], the following formulas (1) and (2) are satisfied:
E(85)5.510.sup.9(1)
[E(40)E(85)]100/E(40)30(2).

A magnetic toner comprising a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein a storage elastic modulus E(40) [Pa] at 40 C. and a storage elastic modulus E(85) [Pa] at 85 C., which are obtained in a powder dynamic viscoelasticity measurement of the magnetic toner, satisfy the following formulas (1) to (3).

E(40)6.010.sup.9 (1)

E(85)5.510.sup.9 (2)

[E(40)E(85)]100/E(40) (3)

A magnetic toner comprising a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein the dielectric loss tangent at 100 kHz is 1.010.sup.2 or more, a variation coefficient CV3 of an occupied area ratio of the magnetic body when a cross section of the magnetic toner particle is divided by a square grid having a side of 0.8 m in cross-sectional observation of the magnetic toner particle using a transmission electron microscope TEM is from 30.0% to 80.0%, and where a storage elastic modulus of the magnetic toner at 40 C. is taken as E(40) [Pa] and a storage elastic modulus of the magnetic toner at 85 C. is taken as E(85) [Pa], the following formulas (1) and (2) are satisfied:

E(85)5.510.sup.9 (1)

[E(40)E(85)]100/E(40)30 (2)

Provided are a magnetic core material for electrophotographic developer and a carrier for electrophotographic developer, which are excellent in charge characteristics and strength and with which a satisfactory image free from defects can be obtained, and a developer containing the carrier.

A magnetic core material for electrophotographic developer, having a sulfur component content of from 50 to 700 ppm in terms of a sulfate ion and a BET specific surface area of from 0.06 to 0.25 m.sup.2/g.

A magnetic chemical toner comprising toner particles with high circularity (i.e., above 0.970) is described. The high circularity of the toner particles can maximize transfer efficiency and prevent toner waste during printing. The toner particles can comprise a polyester resin-based core. If desired, the toner particles can comprise a surface coating to modulate toner properties. Also described is a method of preparing the magnetic toner and a method of using the toner to print an image.

A magnetic toner containing a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein when the inorganic fine particles are classified as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles in accordance with fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X of coverage of the magnetic toner surface by the third inorganic fine particles are in prescribed ranges.