An electrophotographic image forming carrier includes core particles and a coating layer coating a surface of the core particles. The coating layer contains antimony-containing particles comprising inorganic fine particles A and antimony-doped tin oxide disposed on a surface of the inorganic fine particles A. The electrophotographic image forming carrier has an apparent density of 2.0 g/cm.sup.3 or more and 2.5 g/cm.sup.3 or less.

A toner comprising a binder resin and a colorant, wherein the toner has a Martens hardness, as measured at a maximum load condition of 2.010.sup.4 N, of from 200 MPa to 1,100 MPa.

A reversibly allochroic toner contains a binder resin and a colorant. The colorant reversibly switches between first and second color states in response to temperature changes. The colorant exhibits a hysteresis in a temperature-color state curve thereof in which the following relationships are satisfied.

Tr<T.sub.L2<T.sub.L1<T.sub.H1<T.sub.H2<Tg

T.sub.H250 C.

20 C.Tr30 C. where, T.sub.H1 is a temperature at which the colorant starts to change from the first color state to the second color state, T.sub.H2 is a temperature at which the colorant completely changes to the second color state, T.sub.L1 is a temperature at which the colorant starts to change from the second color state to the first color state, T.sub.L2 is a temperature at which the colorant completely changes to the first color state, and Tg is a glass transition temperature of the binder resin.

Provided are a ferrite carrier core material for an electrophotographic developer having a full length L.sub.1 of grain boundary and a circumference length L.sub.2 of the core material in a cross-section of the core material, and satisfying a relationship of 2L.sub.1/L.sub.29; a carrier for an electrophotographic developer including the ferrite carrier core material and a coating layer containing a resin provided on a surface of the ferrite carrier core material; and an electrophotographic developer including the carrier and a toner.

A method for producing a carrier for electrostatic charge image development includes coating magnetic particles by adding the magnetic particles and a coating liquid containing a resin and a solvent to a mixer with a stirring blade to form a resin coating layer on surfaces of the magnetic particles and taking a carrier having the resin coating layer out of the mixer. In the coating, the stirring conditions after the solvent is evaporated and dried by heating in the mixer until the carrier is taken out of the mixer satisfy Formula 1 below and Formula 2 below:
0.2?peripheral speed ?Dn (m/s) of stirring blade?2.0Formula 1,
1?10.sup.3?stirring workload (peripheral speed?stirring time T)?4?10.sup.3Formula 2, where D represents a diameter (m) of the stirring blade, n represents a number of revolutions (rps) of the stirring blade, and T represents a time (s) from a time point at which, after a load power of the stirring blade before drying of the solvent increases with drying until completion of drying, a load power of the stirring blade decreases to 1.3 times or less the load power of the stirring blade before drying to a time point at which stirring in the mixer is stopped.

In a two-component developer, toner particles include toner mother particles and external additive particles including strontium titanate particles. A first percentage content being a percentage content of the strontium titanate particles to the mass of the toner mother particles is 0.30-0.90% by mass. The carrier particles include carrier cores and coat layers. The coat layers contain barium titanate particles and a coating resin including a silicone resin. The barium titanate particles have a number average primary particle diameter of 100-500 nm. A second percentage content being a percentage content of the coat layers to the mass of the carrier cores is 2.0-4.0% by mass. A third percentage content being a percentage content of the barium titanate to the mass of the coating resin satisfies formula (1) (X?10)?Z?45.0. In formula (1), X represents the first percentage content and Z represents the third percentage content.

A toner comprising a binder resin and a colorant, wherein the toner has a Martens hardness, as measured at a maximum load condition of 2.010.sup.4 N, of from 200 MPa to 1,100 MPa.

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.

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 Si localized in the surface thereof is used.