The present invention relates to a binder resin for toners which contains a composite resin that is formed by bonding a styrene-acrylic resin unit and a polyester-based resin unit to each other through a covalent bond, in which an acid value of a styrene-acrylic resin (A) constituting the styrene-acrylic resin unit is not less than 40 mgKOH/g.

A toner comprising a toner particle comprising a binder resin and boric acid, wherein the toner has an average circularity of 0.95 or more, and the toner has a shape factor SF1 of 105 to 125, and a method for producing to provide a toner with excellent durability for which the improvement of transfer rate with the above physical characteristics.

A toner comprising a toner particle comprising a binder resin, a nonmagnetic inorganic oxide particle A, and a magnetic iron oxide particle B, wherein a softening point of a chloroform-soluble component of the toner particle is not greater than 90° C.; the nonmagnetic inorganic oxide particle A and the magnetic iron oxide particle B are internally added to the toner particle; the nonmagnetic inorganic oxide particle A comprises as its main component at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; a proportion of the inorganic oxide particles having a long diameter of specific length is in specific range; and a value of a ratio of a number-average particle diameter of the long diameter for the nonmagnetic inorganic oxide particle A, to a number-average particle diameter of the long diameter for the magnetic iron oxide particle B, is 5 to 30.

The present invention relates to a toner for development of electrostatic images which contains a colorant, a resin composition (P) and a resin composition (W), in which the resin composition (P) is a resin composition formed by subjecting an acid group-containing amorphous polyester-based resin (A) and an amine compound to condensation reaction, and the resin composition (W) is a resin composition formed by subjecting an alcohol component (W-al), a carboxylic acid component (W-ac) and a hydrocarbon wax containing at least one functional group selected from the group consisting of a hydroxy group and a carboxy group to condensation reaction; and a process for producing the toner.

A toner includes toner particles. The toner particles each include a toner mother particle and an external additive attached to the surface of the toner mother particle. The external additive contains specific external additive particles and silica particles. The specific external additive particles each include a base containing barium titanate and a coat layer covering the base. The coat layer contains antimony tin oxide. Mass ratios of metal elements contained in the toner particles satisfy 0.10<(Ba/Si)<0.60 (formula (1)); 0.05<(Ba/Si)<0.20 (formula (2)); and 1.5<(Sn/Ba)<5.0 (formula (3)).

A method for producing a resin fine particle includes dissolving or melting an oily mixture containing at least a polyester resin, a base, and a basic dye while applying a shearing force to the oily mixture, and emulsifying the dissolved or molten oily mixture by adding a surfactant and an aqueous medium while applying a shearing force to the dissolved or molten oily mixture to prepare a dispersion liquid of the resin fine particle. The resin fine particle includes the polyester resin and the basic dye, has a volume average particle diameter of 0.05 μm or more and 1 μm or less, and has a ratio of a concentration of the basic dye in a center of gravity portion of the resin fine particle to a concentration of the basic dye in a surface layer portion having a depth of 10 nm or less from a surface of the resin fine particle of 0.8 or more.

A resin binder composition for toners, containing a polyester resin A having a constituting unit derived from an alcohol component containing an alkylene oxide adduct of bisphenol A and a constituting unit derived from a carboxylic acid component containing an amorphous acid modified product A of an α-olefin polymer having 4 or more carbon atoms and 18 or less carbon atoms; a resin binder composition for toners containing a polyester resin A which is a polycondensate of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing an amorphous acid modified product A of an α-olefin polymer having 4 or more carbon atoms and 18 or less carbon atoms; and a toner for electrostatic image development, containing these resin binder composition for toners. The resin binder composition for toners of the present invention is suitably used for a toner for electrostatic image development which is usable in development of latent images formed in, for example, electrostatic image development method, electrostatic recording method, electrostatic printing method or the like.

A method for producing an electrostatic image developing toner includes mixing toner particles containing an amorphous resin with additive particles. A mixing device used in the mixing includes a stirring vessel, a stirring blade, and a jacket configured to cool the stirring vessel, and condition (1) and condition (2) are satisfied. Condition (1): an internal temperature Ti of the mixing device in the mixing and a glass transition temperature Tg of the amorphous resin contained in a near-surface portion of the toner particles satisfy Tg−50° C.≤Ti<Tg (inequality 1). Condition (2): 0.08≤ (Pm−P0)/w≤0.50 (inequality 2) is satisfied. In inequality 2, Pm represents an average power (kW) of a motor for driving the stirring blade of the mixing device in the mixing, P0 represents an idling power (kW) of the motor, and w represents a total mass (kg) of the toner particles and the additive particles in the mixing device.

A toner processing apparatus processing an object comprising toner particles, comprising a processing chamber having a drive shaft rotatably provided at the bottom of chamber; a rotating member and a flow means pivotally supported by the drive shaft, wherein the rotating member comprises a main portion, and a processing portion protruding outward in the radial direction comprising a plate-shaped processing surface that collides with the object, and a rear wing coupled to the upstream side of the plate-shaped processing surface in a rotation direction; the plate-shaped processing surface protrudes upward from the rear wing; the plate-shaped processing surface away from the main portion is on the downstream side in the rotation direction of the rotating member; and where a radius of inner circumference of processing chamber is denoted by d, the shortest distance between inner wall of processing chamber and plate-shaped processing surface is 0.100d or less.

A toner is provided, which has a toner particle containing a binder resin including a first resin and a second resin, wherein the first resin is a crystalline resin, the second resin is an amorphous resin, the first resin contains a specific amount of a first monomer unit having a specific structure, an acid value of the first resin and an acid value of the second resin are within specific ranges, a domain-matrix structure formed of a matrix containing the first resin and domains containing the second resin appears in cross-sectional observation of the toner, the toner particle contains a multivalent metal element, the multivalent metal element is at least one metal element selected from the group consisting of Mg, Ca, Al, Fe and Zn, and a total content of the multivalent metal element is within a specific range.