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.

A white toner according to an embodiment includes: a raw white toner not containing a colloidal silica and containing a white pigment and a crystalline resin; and 1.0 to 1.1 parts by weight of a colloidal silica per 100 parts by weight of the raw white toner. The white toner has a true density of 1.8 to 2.2 g/cm.sup.3.

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.

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 electrostatic latent image developing toner contains a plurality of toner particles. Each of the toner particles contains, in a surface portion thereof, at least one hydrophobic salt in a state where a cation derived from a first surfactant is ionically bonded to an anion derived from a second surfactant. A ratio of a total mass of the at least one hydrophobic salt to a mass of the toner is 1 ppm or more and 5,000 ppm or less.

The present disclosure relates to a system for electrostatic printing. The system comprises a UV colorant comprising a rare earth diketonate, a thermoplastic resin and an additive selected from at least one of an acid having a pKa of 1 to 5 and a hydroxide. The system may be used to print a security feature on a print substrate.

A toner having a toner particle including a binder resin and a release agent is provided, wherein the binder resin includes a crystalline resin and an amorphous resin, where in differential scanning calorimetry of the toner, a temperature is raised to obtain a differential scanning calorimetry curve A and then the temperature is lowered to obtain a differential scanning calorimetry curve B, the differential scanning calorimetry curve A has endothermic peaks derived from the crystalline resin and the release agent, the differential scanning calorimetry curve B has exothermic peaks derived from the crystalline resin and the release agent, and these endothermic peaks and exothermic peaks satisfy specific relationships, and a storage elastic modulus G(TmB) of the toner at the endothermic peak temperature of the crystalline resin is 1.010.sup.5 Pa to 1.010.sup.8 Pa.

A toner includes a toner particle containing a binder resin, and an organic-inorganic composite fine particle. The binder resin contains 50% by mass or greater of polyester A, U.sub.iso/all acid components100 indicating a content proportion of a unit U.sub.iso derived from isophthalic acid in the polyester A is 60% by mole or greater with respect to an amount of all units derived from the acid components. The organic-inorganic composite fine particle has, on a surface of a resin particle, a plurality of protrusions derived from an inorganic fine particle. The inorganic fine particle includes a silica fine particle, and the resin particle contains an ester group.

A toner has the following constitution. The toner particle contains an inorganic fine particle having a mean particle size in a range from 10 nm to 60 nm. The inorganic fine particle is at least one selected from the group consisting of strontium titanate, silica coated with alumina, titania, and the like. When layers having depths of 0 nm to 10 nm, 10 nm to 100 nm, and 100 nm or more from the surface of the toner particle are defined as toner layers A to C, respectively, an abundance ratio of the inorganic fine particle is the highest in the toner layer B. At the interface (toner layer B) in the electronic image of the toner particle cross section, an interface having a small abundance ratio of the inorganic fine particle and an interface having a large abundance ratio of the inorganic fine particle are present, and the length of both interfaces is 2 m or more. The abundance ratio of the inorganic fine particle in the interface is 15% or less with respect to the interface .

A toner comprising a toner particle comprising a binder resin, wherein the toner particle further comprises a monohydric aliphatic alcohol, and an anionic surfactant having an alkyl group, the binder resin comprises a polyester resin, a carbon number of the monohydric aliphatic alcohol is 8 to 18, a content of the monohydric aliphatic alcohol when extracted from the toner with ethanol is 30 to 300 ppm by mass in the toner, and a value of a ratio (molar ratio) of the monohydric aliphatic alcohol extracted from the toner with ethanol relative to the anionic surfactant having an alkyl group extracted from the toner with methanol is 0.01 to 0.60.