Carrier particles each include a carrier core having recesses in a surface thereof, and first and second coat layers covering the surface of the carrier core. The first and second coat layers are in a multi-layer structure in which the first coat layer and the second coat layer cover the surface of the carrier core in the stated order. The first coat layer entirely covers the surface of the carrier core. The second coat layer selectively covers regions of a surface of the first coat layer that correspond to the recesses in the surface of the carrier core. The first coat layer contains a first resin. The second coat layer contains a second resin. The second coat layer has a lower electric resistance than the first coat layer.

A carrier including a resin layer including at least one kind of particles, wherein the at least one kind of the particles are particles of barium sulfate, wherein an amount of Ba detected is 0.3 atomic % or greater in a Ba analysis through X-ray photoelectron spectroscopy (XPS) of the carrier, and wherein circle-equivalent diameters of the particles of the barium sulfate are 400 nm or greater but 900 nm or smaller.

In a two-component developer, external additive particles of toner particles include resin particles containing a thermoplastic resin. Coat layers of carrier particles contain a coating resin and barium titanate particles. The coating resin includes a silicone resin. The barium titanate particles have a number average primary particle diameter of 100-500 nm. The barium titanate particles have a content of 4-45 parts by mass relative to 100 parts by mass of the coating resin. The rate of the mass of the coat layers to the mass of the carrier cores is 0.10-4.90% by mass. The average of coverage rates of the carrier cores is at least 80.0% and less than 100.0%.

An object of the present invention is to provide a ferrite carrier core material for an electrophotographic developer having desired resistance properties and charging properties with small environmental variation of resistivity and charge amount while maintaining the advantages of ferrite carriers, a ferrite carrier for an electrophotographic developer, an electrophotographic developer using the ferrite carrier, and a method for manufacturing the ferrite carrier core material for an electrophotographic developer. In order to solve the problem, a ferrite carrier core material comprising ferrite particles containing 15 mass % or more and 25 mass % or less of Mn, 0.5 mass % or more and 5.0 mass % or less of Mg, 0.05 mass % or more and 4.0 mass % of Sr, and 45 mass % or more and 55 mass % or less of Fe, with Zr localized in the surface thereof is used.

A carrier core material formed with ferrite particles, the skewness Rsk of the particle is equal to or more than 0.40 but equal to or less than 0.20, and the kurtosis Rku of the particle is equal to or more than 3.20 but equal to or less than 3.50. Here, the maximum height Rz of the particle is equal to or more than 2.20 m but equal to or less than 3.50 m. Moreover, the ferrite particle contains at least either of Mn and Mg elements. In this way, cracking or chipping in a concave-convex portion of a particle surface is unlikely to occur, and moreover, the amount of coating resin used can be reduced without properties such as electrical resistance being lowered.

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.

A developing device, including: a developer containing toner and carrier; and developer bearer configured to have surface thereof bear the developer and endlessly move, and to develop latent image over surface of latent image bearer by supplying toner in developer to latent image in developing region facing the latent image bearer, wherein carrier contains fine particles, value X in volume resistivity R (=10.sup.X) (?.Math.cm) of carrier is 11.5-16.0, developer bearer includes: magnetic field generating unit including a plurality of magnetic poles; and developing sleeve having a cylindrical shape enclosing magnetic field generating unit, and configured to bear developer over outer circumferential surface of cylindrical shape by magnetic force of the magnetic field generating unit and perform surface moving by rotating relative to developing device body, and developing device includes developing sleeve voltage applying unit configured to apply AC component-containing voltage to developing sleeve.

Provided is a carrier for a developer of an electrostatic latent image, the carrier including a core particle, and a resin layer covering the core particle, where the resin layer includes metal compound particles, wherein the metal compound particles include magnesium compound particles or barium compound particles, and an exposed amount B (atomic %) of the magnesium or the barium on a surface of the carrier particle satisfies a relationship below:

10.0B1.2.

A two-component developing agent contains a toner that contains a pulverized toner, the pulverized toner containing at least one type of polyester resin, a styrene-based resin or an aromatic petroleum resin, and Fisher-Tropsch wax, and a carrier that contains a silicone resin covering layer containing conductive fine powder.

Carrier particles each include a carrier core having recesses in a surface thereof, and first and second coat layers covering the surface of the carrier core. The first and second coat layers are in a multi-layer structure in which the first coat layer and the second coat layer cover the surface of the carrier core in the stated order. The first coat layer entirely covers the surface of the carrier core. The second coat layer selectively covers regions of a surface of the first coat layer that correspond to the recesses in the surface of the carrier core. The first coat layer contains a first resin. The second coat layer contains a second resin. The second coat layer has a lower electric resistance than the first coat layer.