A toner for electrostatic image development includes: toner base particles containing at least a nonionic surfactant, a binder resin, and a release agent; and an external additive. The content of the nonionic surfactant is from 0.05% by mass to 1% by mass inclusive based on the total mass of the toner, and the external additive contains particles with an arithmetic mean particle diameter of from 50 nm to 400 nm inclusive. The amount of the external additive released is 5% by mass or less.

A toner for electrostatic image development includes: toner base particles containing at least a nonionic surfactant, a binder resin, and a release agent; and an external additive. The content of the nonionic surfactant is from 0.05% by mass to 1% by mass inclusive based on the total mass of the toner. The external additive contains inorganic particles having an arithmetic mean particle diameter of from 50 nm to 400 nm inclusive and an average circularity of from 0.5 to 0.8 inclusive.

A toner contains toner particles, titanate fine particles having a Group II element, and hydrotalcite compound fine particles as an external additive and satisfying 10Lt80 and 100LhWeight average particle diameter (D4) of toner particles0.50, when the number average particle diameter (D1) of primary particles of the titanate fine particles is defined as Lt (nm) and the number average particle diameter (D1) of primary particles of the hydrotalcite compound fine particles is defined as Lh (nm).

To provide an efficient method for producing a negatively chargeable toner in which a carbon black (as a colorant) is well dispersed and which has high chargeability, has excellent transfer efficiency, prevent a white spot and provides an image with sufficient image density. Disclosed is a method for producing a negatively chargeable toner, the method including: a suspension step of obtaining a suspension in which droplets of a polymerizable monomer composition containing at least a polymerizable monomer, a carbon black, a softening agent and a charge control agent, which is a specific, sulfonic acid group-containing copolymer, are dispersed, by suspending the polymerizable monomer composition in an aqueous dispersion medium containing a dispersion stabilizer, and a step of obtaining colored resin particles by suspension polymerization using the suspension in the presence of a polymerization initiator.

Provided is a toner for developing electrostatic images which is less likely to cause toner ejection and is excellent in printing durability. The toner comprises colored resin particles and external additives, wherein the external additives comprise an external additive A and an external additive B; wherein the external additive A is silica particles being surface-hydrophobized with a specific hydrophobizing agent and having a specific number average particle diameter; and wherein the external additive B is silicone resin particles having a ratio (BS/TS) of a BET specific surface area (BS) to a theoretical specific surface area (TS) in a range of from 3.0 to 30.0, and having a specific number average particle diameter.

A positively chargeable toner includes toner particles each including a toner mother particle and an external additive adhering to a surface of the toner mother particle. The external additive includes first resin particles each having a surface to which a cationic surfactant adheres and second resin particles each having a surface to which an anionic surfactant adheres. Respective number average primary particle diameters of the first resin particles and the second resin particles are at least 60 nm and no greater than 100 nm. A detachment ratio of the first resin particles in a dispersion of the toner subjected to five-minute ultrasonic treatment is no greater than 20% in terms of a peak intensity percentage in a fluorescent X-ray spectrum plotted for the dispersion of the toner. A detachment ratio of the second resin particles in the dispersion is at least 30% and no greater than 60% in terms thereof.

An aqueous developer for a flexographic printing plate capable of maintaining good printing reproducibility and suppressing the adhesion and aggregation of the dispersion in the developer during repeated use, and a method of manufacturing a flexographic printing plate using the same, are provided. The aqueous developer for a flexographic printing plate is an aqueous developer for a flexographic printing plate containing a surfactant having a molecular weight of 1000 or more, and water.

A toner contains toner particles, titanate fine particles having a Group II element, and hydrotalcite compound fine particles as an external additive and satisfying 10Lt80 and 100LhWeight average particle diameter (D4) of toner particles0.50, when the number average particle diameter (D1) of primary particles of the titanate fine particles is defined as Lt (nm) and the number average particle diameter (D1) of primary particles of the hydrotalcite compound fine particles is defined as Lh (nm).

To provide a toner that is less likely to cause image defects due to the detachment of the silica aggregated particle even when having been used for a long period of time in a low-temperature and low-humidity environment. The toner includes: a toner particle containing a binder resin; and a silica aggregated particle, wherein, in TOF-SIMS measurement of the toner particle, a fragment peak derived from a boron atom and a fragment peak derived from a boron-oxygen structure are detected; the silica aggregated particle is an aggregated particle of silica fine particles having a primary particle size based on number of from 20 to 75 nm, a maximum Feret's diameter of the silica aggregated particle is from 110 to 500 nm, and an aspect ratio thereof is from 1.50 to 4.00.

A positively chargeable toner includes toner particles each including a toner mother particle and an external additive adhering to a surface of the toner mother particle. The external additive includes first resin particles each having a surface to which a cationic surfactant adheres and second resin particles each having a surface to which an anionic surfactant adheres. Respective number average primary particle diameters of the first resin particles and the second resin particles are at least 60 nm and no greater than 100 nm. A detachment ratio of the first resin particles in a dispersion of the toner subjected to five-minute ultrasonic treatment is no greater than 20% in terms of a peak intensity percentage in a fluorescent X-ray spectrum plotted for the dispersion of the toner. A detachment ratio of the second resin particles in the dispersion is at least 30% and no greater than 60% in terms thereof.