A carrier for forming an electrophotographic image is provided. The carrier comprises a core particle and a resin layer coating the core particle. The resin layer contains a chargeable particle A, a conductive particle B, a dispersing agent, and a defoaming agent.

A developing device includes a developing container storing a two-component developer containing a magnetic carrier and a toner, a developer carrying member carrying the developer on its outer circumferential surface, and a regulation member arranged to be opposed at a prescribed distance to the developer carrying member. The developer carrying member includes a developing sleeve on which a magnetic brush is formed, and a magnet secured in the developing sleeve and having a plurality of magnetic poles including a regulation pole opposed to the regulation member and a downstream-side magnetic pole arranged downstream of the regulation pole with respect to the rotation direction of the developing sleeve. The magnet is such that the vertical magnetic force gradient [mT/° ] has a local minimum value near a position at which the vertical magnetic force is 0 [mT] between the downstream-side surface of the regulation member and the downstream-side magnetic pole.

A carrier is provided that includes a core particle and a coating layer coating the core particle. The coating layer includes a resin and chargeable inorganic fine particles, and has voids. The resin has an average film thickness of 0.10 μm or larger and smaller than 0.45 μm. The coating layer has a porosity of 0.1% or higher and lower than 2.8%, when the porosity expressed by the following equation:

Porosity [%]=S1/S2×100

where, on a cross section of the coating layer, S1 represents a cross sectional area of the voids and S2 represents a cross sectional area of the resin.

A magnetic carrier including a magnetic carrier particle having a magnetic core particle and a coating layer of an organosilicon polymer on a surface of the magnetic core particle, wherein the organosilicon polymer has the structure given by formula (T3) below; in .sup.29Si-NMR measurement of the THF-insoluble matter of the organosilicon polymer, the ratio ST3 of the peak area for the structure given by formula (T3) to the total peak area for the organosilicon polymer is at least 0.05; and in the roughness curve measured on the magnetic carrier particle, the mean width (RSm) of the roughness curve elements of the magnetic carrier particle, and the ratio (σ/RSm) to this RSm of the standard deviation σ of the width of the region where one period of a protrusion and a recess occurs, are in prescribed ranges.
R—Si(O.sub.1/2).sub.3  (T3) R in the formula represents a prescribed substituent.

An electrostatic charge image developer includes a toner that includes a toner particle; and a carrier, wherein the toner particle contains a brilliant pigment, an exposed amount of the brilliant pigment contained in the toner particle is from 0.5% to 5%, the carrier has a core particle and a coating layer which covers a surface of the core particle, the coating layer contains a silicone resin and a siloxane oligomer, and a content of the siloxane oligomer is from 0.1 ppm to 500 ppm with respect to a total weight of the coating layer.

The present invention provides a magnetic carrier for an electrophotographic developer which has an excellent durability and a stable charging property and is free from occurrence of spent toner thereonto, and a two-component system developer comprising the magnetic carrier for an electrophotographic developer and a toner. The present invention relates to a core material of a magnetic carrier for an electrophotographic developer comprising spherical composite particles comprising at least ferromagnetic iron oxide fine particles and a cured phenol resin and having an average particle diameter of 1 to 100 μm, a resin index of the spherical composite particles being within the range of 35 to 80%, and a magnetic carrier obtained by coating a surface of respective particles of the magnetic carrier core material with a resin.

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 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) (Ω.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.

Ferrite particles have, as a main component, a material represented by a composition formula M.sub.xFe.sub.3−xO.sub.4 (where M is at least one type of metal selected from a group made of Mg, Mn, Ca, Ti, Cu, Zn, Sr and Ni, 0<x<1), where the maximum height Rz of the particles falls within a range of 1.40 μm to 1.90 μm, and the degree of distortion Rsk of the particles falls within a range of −0.25 to −0.07. In this way, when the ferrite particles are used as the carrier of an electrophotographic image forming apparatus, even if an image formation speed is increased, the occurrence of a failure is reduced for a long period of time.

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 πDn (m/s) of stirring blade≤2.0   Formula 1,

1×10.sup.3≤stirring workload (peripheral speed×stirring time T)≤4×10.sup.3   Formula 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.