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.

An electrostatic image developer includes: a toner A to which silica particles (A) containing an elemental nitrogen-containing compound containing elemental molybdenum are externally added; and a carrier B including a core material and a coating resin layer that covers the core material and contains inorganic particles. In the silica particles (A), the ratio N.sub.Mo/N.sub.Si of a Net intensity N.sub.Mo of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity N.sub.Si of elemental silicon that is measured by the X-ray fluorescence analysis is from 0.035 to 0.45 inclusive.

An electrostatic charge image developer includes: a toner A incorporating toner particles and silica particles (A) as an external additive, the toner particles containing a binder resin and resin particles, and the silica particles (A) containing a nitrogen-containing compound containing the element molybdenum; and a carrier B incorporating a core and a coating resin layer, the coating resin layer covering the core and containing inorganic particles, and the ratio N.sub.Mo/N.sub.Si is 0.035 or greater and 0.45 or less, where N.sub.Mo and N.sub.Si are measured net intensities for the element molybdenum and the element silicon, respectively, in the silica particles (A) in x-ray fluorescence analysis.

Provided is an electrostatic latent image developing toner including toner mother particles having an external additive on a surface of the toner mother particles, wherein the external additive contains inorganic particles and aliphatic acid metal salt particles; the inorganic particles have a number average particle diameter in the range of 10 to 50 nm, and have a Mohs hardness of 8 or more; and the aliphatic acid metal salt particles have a number average particle diameter in the range of 0.4 to 2.0 m.

An electrostatic charge image developing carrier contains a magnetic particle and a resin coating layer coating the magnetic particle, in which the resin coating layer contains inorganic particles, a ratio B/A of a surface area B of the carrier to a plan view area A of the carrier that are obtained by three-dimensional analysis of a surface of the carrier is 1.020 or more and 1.100 or less, a volume average particle diameter of the magnetic particle is 25 ?m or more and 34 ?m or less, and a fluidity of the magnetic particle is 28 s/50 g or more and 36 s/50 g or less.

A two-component developer includes toner particles and carrier particles. The toner particles each include a toner mother particle and first resin particles. The carrier particles each include a carrier mother particle and second resin particles. An amount of the second resin particles is at least 0.010 parts by mass and no greater than 0.100 parts by mass relative to 100 parts by mass of the carrier mother particles. The first resin particles and the second resin particles have a number average primary particle diameter of at least 40 nm and no greater than 100 nm and a blocking rate (measurement temperature: 160 C.) of less than 30% by mass. A difference in blocking rate between the first resin particles and the second resin particles is no greater than 5% by mass, and a difference in number average primary particle diameter therebetween is no greater than 5 nm.

A carrier including a carrier core; and a coating thereover; wherein the coating comprises a polymer having a low molecular weight of from about 100,000 to about 300,000 g/mole and a particle size of from about 0.05 to about 0.6 micrometer. A developer including a toner; and a carrier; wherein the carrier comprises a carrier core; and a coating thereover; wherein the coating comprises a polymer having a low molecular weight of from about 100,000 to about 300,000 g/mole and a particle size of from about 0.05 to about 0.6 micrometer. A process for preparing a carrier including providing a carrier core; and disposing a polymer coating thereover by combining the carrier core and the polymer coating in a mixing device; optionally, fusing the coating to the carrier core; wherein the coating comprises a polymer having a low molecular weight of from about 100,000 to about 300,000 g/mole and a particle size of from about 0.05 to about 0.6 micrometer.

A carrier for a developer of an electrostatic latent image, the carrier including: core particles having magnetism; and a coating layer coating a surface of each of the core particles, wherein the coating layer includes two or more kinds of inorganic particles, at least one kind of inorganic particles among the two or more kinds of inorganic particles is inorganic particles A having conductivity and a peak particle diameter of from 300 nm through 1,000 nm, and surface roughness of the carrier calculated by Formula 1 below is from 1.10 m.sup.2/g through 1.90 m.sup.2/g,
CFFormula 1
where C is a BET specific surface area (m.sup.2/g) of the carrier and F is a BET specific surface area (m.sup.2/g) of the core particles.

An electrostatic latent image developing carrier includes carrier particles each including a carrier core and first and second coat layers covering a surface of the carrier core. The first and second coat layers give a layered structure in which the first coat layer and the second coat layer are layered in order from the surface of the carrier core. The first coat layer contains a fluororesin. The second coat layer contains a silicone resin and a fluorine silane in an amount of at least 1% by mass relative to a mass of the silicone resin. An area S.sub.A of a region of a surface region of the first coat layer that is covered with the second coat layer and an area S.sub.B of a region thereof that is not covered with the second coat layer satisfy a relationship represented by 0.05S.sub.B/(S.sub.A+S.sub.B)0.50.

An object of the present invention is to provide a carrier low in specific gravity and less in both environmental fluctuation and change of the charge amount after aging, an electrophotographic developer using the carrier, and a method of manufacturing the carrier. To achieve the object, the carrier is manufactured by coating a core material composed of a magnetic component and a non-magnetic component with a resin, and the carrier is characterized in that water content is 200 ppm or less and cyclic siloxane content is 100 ppb or less. Further, an electrophotographic developer containing the carrier is provided.