Abstract: The present invention provides: a ferrite particle containing a crystal phase component containing a perovskite crystal represented by the compositional formula RZrO3 (where R is an alkaline earth metal element); and an electrophotographic developer carrier core material, an electrophotographic developer carrier, and an electrophotographic developer containing the ferrite particles.

Abstract: Disclosed herein is a release fluid, a fuser member and an image forming apparatus. The release fluid includes an amino functional silicone fluid, a non-functional silicone fluid; and vitamin E.

Abstract: A magnetic carrier, which is suppressed from causing the loss and wear of a magnetic carrier coating resin even when used for a long time period, and achieves a stable image density and a reduction in toner scattering. In the magnetic carrier, the resin coating layer contains a resin A having a fluorine polymer moiety, the resin coating layer has an average thickness of 50 nm or more, a ratio F(x) (atomic %) of a fluorine atom detected at a position at a depth of x nm from a surface of a magnetic carrier particle by X-ray photoelectron spectroscopy satisfies formula (1) and formula (2), and when x represents an integer of 0 or more and 20 or less, F(x) satisfies formula (3): 5.0?F(0)?15??(1) F(20)?5.0??(2) |F(x+1)?F(x)|?7.5??(3).

Abstract: An external additive for toner, wherein the external additive is an organosilicon polymer particle, and defining A (nm) as the number-average particle diameter of primary particles of the external additive measured using a scanning electron microscope, and defining B (nm) as the number-average particle diameter of the external additive measured in accordance with a centrifugal sedimentation method, the A and the B satisfy a following Expression (1): 1.5?B/A?3.0??(1).

Abstract: An electro-conductive member for an electrophotographic image forming apparatus for which a change in resistance value is small even when a large current is applied at a high voltage for a long period of time is provided. The electro-conductive member includes a support having an electro-conductive outer surface and an electro-conductive layer on the outer surface of the support, in which the electro-conductive layer has a matrix including a cross-linked product of a first rubber and domains dispersed in the matrix, the domains include a cross-linked product of a second rubber different from the first rubber and an electrically conductive agent, and the cross-linked product of the second rubber has, in a molecule, a structural unit represented by Structural Formula (I). [—(CH2)n—O—]??Structural Formula (I) In Structural Formula (I), n is an integer of 1 to 3.

Abstract: The toner contains a toner particle having a core-shell structure including: a core containing a binder resin and a colorant; and a shell, wherein the toner contains a crystalline material, and the shell contains an amorphous thermoplastic resin; and when SP values of the crystalline material and the amorphous thermoplastic resin, which are calculated by the Fedors method, are defined as SPc (J/cm3)0.5 and SPa (J/cm3)0.5, respectively, the SPc and the SPa (J/cm3) satisfy a particular relationship, and when the toner is observed by SEM after the toner has been subjected to ruthenium staining that treats the toner in an atmosphere of RuO4 gas having 500 Pa for 15 minutes, a ratio S2 (%) of an area occupied by the crystalline material per area of the toner satisfies a particular relationship.

Abstract: Provided are magnetic particles (cobalt ferrite) having a micrometer-order average particle diameter and similar particle diameters. A cobalt ferrite precursor is heated in the presence of a sulfite, thereby obtaining intended cobalt ferrite magnetic particles.

Abstract: A resin composition includes: a resin having a first group capable of forming at least two hydrogen bonds; and a photoisomerization compound having a second group capable of forming at least two hydrogen bonds complementarily with the first group and having a moiety that is reversibly isomerized by light.

Abstract: An electrostatic image developing toner includes a toner particle including a binder resin and a colorant. The net intensity NS of sulfur included in the toner particle and the total net intensity NA of an alkali metal and an alkaline-earth metal included in the toner particle, which are measured by X-ray fluorescence analysis, satisfy 1.0<NS/NA<22.0.

Abstract: A toner includes a toner particle containing a resin component including a crystalline resin and an amorphous resin. In a cross-sectional observation of the toner particle, a domain-matrix structure which comprises a matrix containing the crystalline resin and domains containing the amorphous resin is observed. The maximum endothermic peak temperature Tm of the toner determined by DSC is 50° C. to 80° C. When the storage elastic modulus of the toner at a temperature 5° C. lower than Tm is G?(?5) (Pa), and the storage elastic modulus of the toner at a temperature 5° C. higher than Tm is G?(+5) (Pa), G?(?5) and G?(+5) satisfy inequality (1), and when the maximum loss tangent of the toner in a temperature range of from 50° C. to 130° C. is tan ? (Max), tan ? (Max) satisfies inequality (2).

Abstract: A toner includes toner base particles each including: a binder resin, a colorant, and wax; and resin particles on surfaces of the toner base particles. A standard deviation of a distance between the resin particles next to each other on the surfaces of the toner base particles is less than 500 nm.

Abstract: A resin binder composition for toners, containing a polyester resin A which is a polycondensate A of raw materials A containing an alkylene oxide adduct of bisphenol A, an aromatic dicarboxylic acid compound, a trivalent or higher polyvalent raw material monomer being at least any one of a trihydric or higher polyhydric alcohol and a tricarboxylic or higher polycarboxylic acid compound, and an amorphous acid modified product A of an ?-olefin polymer having 4 to 18 carbon atoms, the polyester resin A having a softening point of 120° C. to 150° C.; and a toner for electrostatic image development, containing the resin binder composition. The resin binder composition is suitable for a toner for electrostatic image development used in development of latent images formed in electrostatic image development, electrostatic recording and electrostatic printing.

Abstract: Provided is a magenta toner which shows sharper color and higher reflection density than ever before, which is excellent in balance between low-temperature fixability and heat-resistant shelf stability, and which has excellent printing durability. Also provided is a method for producing the magenta toner.

Abstract: A toner for developing an electrostatic charge image contains toner particles containing an amorphous resin and a crystalline resin. The ratio Qs1/Qf1 is 1.1 or more and 2.0 or less, where Qf1 is the total area of all endothermic peaks detected during the first temperature rise when the toner particles are analyzed by differential scanning calorimetry after one-day storage under 50° C. conditions, and Qs1 is the total area of all endothermic peaks detected during the first temperature rise when classified toner particles are analyzed by differential scanning calorimetry after one-day storage under 50° C. conditions. The classified toner particles are a fraction of the toner particles in which toner particles having a diameter equal to or larger than the volume-average diameter D50v of the toner particles constitute 10% by number or less.

Abstract: A magnetic carrier including: a magnetic core; and a coating resin that coats a surface of the magnetic core, wherein the resin coating layer has a thickness of 50 nm or more, a coating resin, which forms the resin coating layer, contains a resin S having an organosilicon polymer moiety, and when a surface and a position at a depth of 20 nm from the surface of the magnetic carrier are analyzed by X-ray photoelectron spectroscopy, an amount of silicon element as determined by the analysis has a ratio within a specific range at respective positions.

Abstract: A toner for developing an electrostatic charge image contains toner particles containing an amorphous resin and a crystalline resin. The ratio Qs1/Qf1 is 1.1 or more and 2.0 or less, where Qf1 is the total area of all endothermic peaks detected during the first temperature rise when the toner particles are analyzed by differential scanning calorimetry after one-day storage under 50° C. conditions, and Qs1 is the total area of all endothermic peaks detected during the first temperature rise when classified toner particles are analyzed by differential scanning calorimetry after one-day storage under 50° C. conditions. The classified toner particles are a fraction of the toner particles in which toner particles having a diameter equal to or larger than the volume-average diameter D50v of the toner particles constitute 10% by number or less.

Abstract: A method for producing a resin particle dispersion includes: preparing a phase-inverted emulsion by phase inversion emulsification of a resin using an organic solvent and an aqueous medium; and removing the organic solvent from the phase-inverted emulsion contained in a distillation tank by reduced pressure distillation. During the reduced pressure distillation, the rate of pressure reduction in an environment in which the pressure inside the distillation tank is equal to or higher than vapor pressure and equal to or lower than (the vapor pressure+5 kPa) when the concentration of the organic solvent in the phase-inverted emulsion is in the range of 30% by mass or less to 1% by mass or more is from 0.01 kPa/min to 0.5 kPa/min inclusive until the pressure inside the distillation tank reaches a preset reduced pressure for the reduced pressure distillation.

Abstract: A preparing method of an electrostatic charge image developing toner includes: aggregating binder resin particles in a dispersion containing the binder resin particles to form aggregated particles; and coalescing the aggregated particles by heating a dispersion containing the aggregated particles to form toner particles. The aggregating includes stirring the dispersion in the aggregating at a required stirring power of 1.0 kW/m3 or more and 6.0 kW/m3 or less per unit volume, and the preparing method satisfies the following Requirement (1), in which Requirement (1): a viscosity of the dispersion during the stirring is 5 Pa·s or more and 50 Pa·s or less at a shear rate of 1/s, where the viscosity of the dispersion is measured at a sample temperature of 25° C. using a part of the dispersion as a sample.

Abstract: An electrostatic charge image developing toner includes a toner particle, and the toner particle includes: a core particle containing a large-diameter particle having a number average particle diameter of 1 ?m or more; and a shell layer that includes at least two resin layers each containing an amorphous resin and covers a surface of the core particles, and an outermost layer of the at least two resin layers is a resin layer being made of the amorphous resin.

Abstract: An electrostatic charge image developer containing: a toner containing a toner particle and an external additive; and a carrier containing a magnetic particle and a resin layer covering the magnetic particle, in which the toner particle has a surface property index value of 2.0 or more and 2.8 or less; and the carrier has a surface having a ratio B/A of a surface area B to a planar view area A of 1.020 or more and 1.100 or less, the planar view area A and the surface area B being obtained by three-dimensional analysis of the surface of the carrier.