The invention provides a process for preparing core-shell composite particles comprising a polyester, polymerized ethylenically unsaturated silane compounds, and optionally a hydrophobic surface treatment. The invention further provides a composite particle comprising a polyester and a radically polymerized ethylenically unsaturated silane compound.

A method for producing a carrier for developing an electrostatic charge image, the method includes: adding a coating liquid containing a resin, conductive particles, and a solvent and magnetic particles to a mixer having a stirring blade, and mixing the coating liquid and the magnetic particles to obtain a mixture; and evaporating and drying the solvent from the mixture to produce a carrier having a resin coating layer on surfaces of the magnetic particles, wherein a viscosity μ of the coating liquid when being added to the mixer is more than 60 mPa.Math.s and 1,000 mPa.Math.s or less, and a value of a ratio μ/W of the viscosity μ(mPa.Math.s) to an amount W (parts by mass) of the resin coating layer with respect to 100 parts by mass of the magnetic particles in the carrier is 20 or more and 500 or less.

A carrier for developing an electrostatic charge image includes magnetic particles and a resin coating layer covering the magnetic particles, the resin coating layer containing aggregates of inorganic particles. The arithmetic mean diameter of the aggregates of inorganic particles on the carrier surface is 30 nm or more and 150 nm or less, and the percentage surface exposure of the magnetic particles is 0% by area or more and 5% by area or less.

An electrostatic charge image developing carrier includes a magnetic particle and a coating resin layer that covers the magnetic particle, and an amount of the coating resin layer that is peeled off from the magnetic particle when the carrier dispersed in water is irradiated with ultrasonic waves, relative to a coating amount of the coating resin layer before ultrasonic irradiation, is 800 mass ppm or more and 2,000 mass ppm or less, and a difference between an initial coating amount of the coating resin layer of a carrier having no travel history and a coating amount of the coating resin layer of a carrier having a travel history and being taken out from an electrostatic charge image developer, relative to the initial coating amount of the coating resin layer, is 0 mass ppm or more and 3,000 mass ppm or less.

The present invention provides: a ferrite carrier core material for an electrophotographic developer, the material having a mesh passing amount of 3 wt % or less as indicated by the ratio of the weight of particles passing through a 16 μm-mesh to the weight of whole particles constituting a powder, and having a particle strength index of 2 wt % or less as indicated by a difference between the mesh passing amounts before and after crushing; a ferrite carrier which is for an electrophotographic developer and in which the surface of the ferrite carrier core material is coated with a resin; and an electrophotographic developer which includes the ferrite carrier and a toner.

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 μm or more and 34 μm or less, and a fluidity of the magnetic particle is 28 s/50 g or more and 36 s/50 g or less.

An electrostatic charge image developing carrier, containing: a magnetic particle; and a resin coating layer that coats the magnetic particle and contains inorganic particles, and the electrostatic charge image developing carrier has a surface of a surface roughness satisfying a ratio B/A of a surface area B to a plan view area A of 1.020 or more and 1.100 or less, the plan view area A and the surface area B being obtained by three-dimensional analysis of the surface, and the magnetic particle has a surface roughness satisfying 0.5 μm≤Sm≤2.5 μm and 0.3 μm≤Ra≤1.2 μm, and Sm represents an average ruggedness interval and Ra represents an arithmetic average surface roughness.

A magnetic carrier comprises a magnetic carrier core and a coating resin layer coating a surface of the magnetic carrier core. The coating resin layer contains resin A and resin B at contents of 1% to 50% by mass and 50% to 90% by mass, respectively, based on resin components of the coating resin layer. The resin A has a first partial structure and a second partial structure, while the resin B has a third partial structure and a fourth partial structure. The mass X of the resin A, the total mass Ma of the first partial structure, and the total mass Mb of the second partial structure satisfy 0.50≤(Ma+Mb)/X≤1.00 and 0.10≤a/b≤30.0, and the SP value of the first partial structure SPa1 and the SP value of the third partial structure SPb3 satisfy 0≤|SPa1—SPb3|≤10.0.

An electrostatic image developing toner includes a toner particle, an external additive A, and an external additive B. At least the external additive A is present on the surface of the toner particles. At least the external additive B is present on the external additive A. The number of peaks of the external additive B on the external additive A is 5 or more and 100 or less per 30 μm peripheral length of the toner particle, the peaks having a height from the surface of the toner particle of 80 nm or more and 250 nm or less.

A carrier for forming an electrophotographic image is provided. The carrier comprises a core particle and a coating layer coating the core particle. The coating layer contains a conductive component comprising an element A, and a coating resin comprising an element B. The element A is undetected in the coating resin by an energy dispersive X-ray spectrometer, and the element B is undetected in the conductive component by the energy dispersive X-ray spectrometer. A standard deviation of a value A/B is 0.4 or less, where the value A/B is a ratio of the element A to the element B in intensity measured by the energy dispersive X-ray spectrometer.