A method for manufacturing a surface-treated gas-phase-process silica particle, the method including steps of: adding 1,3-divinyl-1,1,3,3-tetramethyldisilazane to a raw material gas-phase-process silica particle and introducing a vinyldimethylsilyl group on a surface of the raw material gas-phase-process silica particle to obtain a preliminarily treated silica particle; and adding hexamethyldisilazane to the preliminarily treated silica particle and introducing a trimethylsilyl group on a surface of the preliminarily treated silica particle to obtain a surface-treated gas-phase-process silica particle.

The present invention provides a two-component developer for developing an electrostatic charge image, which includes a toner and a carrier, wherein the toner contains an amorphous resin and a crystalline resin as binder resins and an inorganic particle as external additive particle, and the carrier has a surface to which silica particles having a number average particle diameter of 10 to 30 nm are attached in an amount in the range of the following Equation (1): 5 at %S110 at %, wherein S1 represents a concentration of Si element as measured by XPS and indicates an amount of silica on the surface of the carrier.

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 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.

There is provided a carrier including a magnetic core material having a surface coated with a surfactant-containing resin mixture of an elemental fluorine-containing resin and a polyimide resin. The carrier has an elution amount of an eluted material into water in an elution test ranging from 180 ppm to 3,500 ppm.

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.

The present invention provides a two-component developer for developing an electrostatic charge image, which includes a toner and a carrier, wherein the toner contains an amorphous resin and a crystalline resin as binder resins and an inorganic particle as external additive particle, and the carrier has a surface to which silica particles having a number average particle diameter of 10 to 30 nm are attached in an amount in the range of the following Equation (1): 5 at %S110 at %, wherein S1 represents a concentration of Si element as measured by XPS and indicates an amount of silica on the surface of the carrier.

A two-component developer includes a toner and a carrier. The toner is a positively chargeable toner that is positively charged by friction with the carrier. The toner includes a plurality of toner particles each including a toner mother particle and a plurality of first resin particles. An anionic surfactant having higher negative chargeability than the first resin particles is present on surfaces of the first resin particles. The carrier includes a plurality of carrier particles each including a carrier mother particle and a plurality of second resin particles. A cationic surfactant having higher positive chargeability than the second resin particles is present on surfaces of the second resin particles. The first resin particles have a zeta potential lower than 0 mV at a pH of 5. The second resin particles have a zeta potential higher than 0 mV at a pH of 5.

An object of the present invention is to provide a carrier in which decrease in specific gravity is achieved and a volatile organic compound (VOC) is reduced and to provide an electrophotographic developer using the carrier. There is provided a carrier including a core material coated with a resin, the core material including a magnetic component and a nonmagnetic component, wherein the sum total of volatile organic compounds is 1 ppb or more and 1.5 ppm or less. There is also provided an electrophotographic developer using the carrier.

Methacrylate resins of at least one bio-based methacrylate monomer, where the monomer includes a rosin or isosorbide moiety obtained from natural sources, can be used in toner, carrier coating or both.