A carrier core material is represented by a composition formula M.sub.xFe.sub.3-xO.sub.4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X1), in which 5 to 20 number percent of bound particles where 2 to 5 spherical particles are bound together are contained and in which the maximum peak-to-trough depth Rz of the surface of normal spherical particles other than the bound particles is equal to or more than 1.5 m but equal to or less than 2.1 m. In this way, it is possible to increase the amount of toner supplied to a development region, and the surface of a photosensitive member is prevented from being scratched by a magnetic brush.

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.

A carrier core material is represented by a composition formula M.sub.xFe.sub.3-xO.sub.4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X1), in which 5 to 20 number percent of bound particles in which 2 to 5 spherical particles are bound together are contained, and in which the absolute value of a difference between lattice constants before and after milling which are calculated from a peak position of plane indices in a powder X-ray diffraction pattern is equal to or less than 0.005. In this way, it is possible to increase the amount of toner supplied to a development region, and even when cracking or chipping occurs in the carrier core material, an image failure such as black spots or white spots is prevented from being generated.

An electrostatic charge image developer contains: a toner containing a toner particle and an external additive; and a carrier containing a magnetic particle and a resin layer covering the magnetic particle; and the toner particle has a surface property index value of 1.0 or more and less than 2.0; and the carrier has a surface having a ratio B/A of a surface area B to a plane view area A of 1.020 or more and 1.100 or less, the plane view area A and the surface area B being obtained by three-dimensional analysis of the surface of the carrier.

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.

A toner includes a plurality of toner particles (10) each including a toner mother particle (11) and a plurality of external additive particles (12) attached to a surface of the toner mother particle (11). The external additive particles (12) each include a silica particles (12a), a metal hydroxide layer, and a coating layer (12b). The metal hydroxide layer is disposed on a surface of the silica particle (12a). At least a part of the coating layer (12b) is disposed on a surface of the metal hydroxide layer. The coating layer (12b) is made substantially from a nitrogen containing resin.

A carrier core material is represented by a composition formula M.sub.xFe.sub.3-xO.sub.4 (where M is Mn and/or Mg, and X is a total of Mn and Mg and is a substitution number of Fe by Mn and Mg, 0<X1), in which 5 to 20 number percent of bound particles where 2 to 5 spherical particles are bound together are contained and in which the maximum peak-to-trough depth Rz of the surface of normal spherical particles other than the bound particles is equal to or more than 1.5 m but equal to or less than 2.1 m. In this way, it is possible to increase the amount of toner supplied to a development region, and the surface of a photosensitive member is prevented from being scratched by a magnetic brush.

A carrier for two-component developer includes a magnetic particle and a resin coating layer that covers the magnetic particle and contains a resin, wherein a weight average molecular weight of the resin contained in the resin coating layer is from 1,800,000 to 5,000,000.

A carrier core material is provided that is formed with ferrite particles which can uniformly adhere a coupling agent to the entire surface. A carrier core material is formed with ferrite particles, and the powder pH of the ferrite particles is equal to or more than 9. Here, the ferrite particles are preferably formed of Mn ferrite or MnMg ferrite. The ferrite particles preferably contain 45 wt % or more but 65 wt % or less of Fe, 15 wt % or more but 30 wt % or less of Mn and 5 wt % or less of Mg.

An electrostatic charge image developing carrier includes magnetic particles and a resin coating layer which covers the magnetic particles, wherein a sulfate ion concentration of the resin coating layer is 0.05% by weight or less with respect to a total weight of the resin coating layer, and when a total value of a molar amount of sulfate ions contained and a molar amount of sulfo groups contained per 1 g of the resin coating layer is A mol and a molar amount of sodium ions contained per 1 g of the resin coating layer is B mol, a relationship of 0.1<B/A<1.2 is satisfied.