Abstract: Disclosed is a toner obtained by coating surfaces of core particles including at least a binder resin having a carboxyl group and a coloring agent with successive coatings of a water-soluble crosslinking agent capable of crosslinking with a carboxyl group and a water-soluble polymer having a carboxyl group, which have been successively applied on the core particles and crosslinked with each other. The thus-formed toner is provided with a good harmony of favorable fixability represented by a low lowest fixable temperature and favorable storage stability represented by little aggregation after standing at 50° C. for 8 hours.

Abstract: Disclosed is a decolorable toner produced by aggregating dispersed fine particles of a color material containing at least a color-forming compound, a color-developing agent and a decoloring agent with dispersed fine particles containing at least a binder resin having a carboxyl group, then adding a compound having a carbodiimide group or an epoxy group reactive with the carboxyl group of the binder resin, and thereafter fusing the aggregate particles, respectively in an aqueous medium. The thus obtained decolorable toner can suppress the generation of fine powder by the release of erasable color material fine particles from the toner particles.

Abstract: According to one embodiment, an erasable toner of the present embodiment includes a binder resin, an electron donating coloring agent, an electron accepting developer, and a discoloring temperature regulating agent, in which when measuring for the first time by differential thermal scanning calorimetry, an endothermic peak temperature Tg of the binder resin and an endothermic peak temperature Th of the discoloring temperature regulating agent satisfy Tg<Th and Th?Tg>25° C.

Abstract: According to one embodiment, a method of manufacturing an erasable toner includes washing toner particles including therein a coloring material that is erasable by heating and a binder resin to obtain a toner cake having the amount of water of 20% by weight to 60% by weight, and drying the toner cake at 40° C. or more and at a temperature which is lower than the complete color erasing temperature of the toner particles by 30° C. or more.

Abstract: A color-fadable developer contains a binder resin, a color generation compound and a color developing agent. When the developer is heated from a temperature range of 0° C. to 20° C. to a temperature range of 150° C. to 180° C. at a temperature increase rate range of 5° C./min to 10° C./min a first time and a second time, a first differential scanning calorimetry curve based on a measurement by differential scanning calorimetry during the first heating has an endothermic peak that is missing from a second differential scanning calorimetry curve based on a measurement differential scanning calorimetry during the second heating, and has a different peak than the endothermic peak caused by a glass transition point of a binder resin.

Abstract: Disclosed is a decolorable toner produced by aggregating dispersed fine particles of a color material containing at least a color-forming compound, a color-developing agent and a decoloring agent with dispersed fine particles containing at least a binder resin having a carboxyl group, then adding a compound having a carbodiimide group or an epoxy group reactive with the carboxyl group of the binder resin, and thereafter fusing the aggregate particles, respectively in an aqueous medium. The thus obtained decolorable toner can suppress the generation of fine powder by the release of erasable color material fine particles from the toner particles.

Abstract: Disclosed is a toner obtained by coating surfaces of core particles including at least a binder resin having a carboxyl group and a coloring agent with successive coatings of a water-soluble crosslinking agent capable of crosslinking with a carboxyl group and a water-soluble polymer having a carboxyl group, which have been successively applied on the core particles and crosslinked with each other. The thus-formed toner is provided with a good harmony of favorable fixability represented by a low lowest fixable temperature and favorable storage stability represented by little aggregation after standing at 50° C. for 8 hours.

Abstract: Disclosed is a process for production of a decolorable toner, including: aggregating dispersed fine particles of a color material comprising at least a color-forming compound, a color-developing agent and a decoloring agent with dispersed fine particles comprising at least a binder resin comprising a polyester resin to form aggregates in an aqueous medium, adding a reactive polymer having an oxazoline group in to the aqueous medium, and fusing the aggregates in the aqueous medium. As a result, it becomes possible to produce a decolorable toner which suppresses the generation of fine powder due to the release of fine particles of an erasable color material from the toner.

Abstract: Encapsulated toner particles are formed by: aggregating core material particles containing at least a colorant and a core material resin in an aqueous dispersion medium to form core particles; adding coating resin particles into the aqueous dispersion medium during progress of the formation of the core material at a point of time when the volume-based median particle diameter of the core particles formed by the aggregation reaches 30 to 83% of that of desired toner particles; and continuing the aggregation to form a coating layer composed of a composite aggregate of the core material particles and the coating resin particles on the core material. In the thus-obtained toner, the colorant is uniformly and well incorporated in the toner particles, and therefore, the coloring ability is improved without causing a problem of release of fine powder.

Abstract: The method for producing a developing agent according to the invention contains subjecting the toner material dispersion liquid to mechanical shearing to make the granular mixture into fine particles, thereby providing a dispersion liquid containing fine particles having a smaller particle diameter than a particle diameter of the granular mixture. The toner material dispersion liquid is subjected to mechanical shearing under a temperature of a glass transition point Tg of the binder resin or more and a pressure of 10 MPa or more, and the resulting dispersion liquid containing the fine particles is depressurized with two or more stages while maintaining the temperature of a glass transition point Tg of the binder resin or more and then cooled to a temperature of a glass transition point Tg of the binder resin or less.

Abstract: Disclosed is an electrophotographic toner, including toner particles which contain at least a binder resin and a coloring agent and have been prepared in an aqueous medium, wherein the surfaces of the toner particles are treated with an Si compound in an amount of from 0.1 to 5.0 wt % calculated as SiO2 and with a Ti oxide in an amount of from 0.1 to 3.0 wt % calculated as TiO2. The toner has a dielectric loss (tan ?) of from 1×103 to 10×103 in an environment of 10° C. and 20% relative humidity (RH) and from 3×103 to 15×103 in an environment of 30° C. and 85% RH, and also has a triboelectric charge (q/m) of from 20 to 50 ?C/g in an environment of 10° C. and 20% RH and from 10 to 35 ?C/g in an environment of 30° C. and 85% RH. According to this configuration, electrophotographic properties are improved as represented by: a low environmental variation in chargeability; a decrease in amount of scattered toner; and less fogging.

Abstract: A developing agent including a core containing an amorphous polyester resin and a fatty acid ester based wax, a shell provided on the surface of the core and containing a copolymer of an aromatic vinyl monomer and acrylic acid or an acrylic ester, and a coloring agent.

Abstract: A method for producing a developing agent contains mechanically shearing a mixture containing a polyester resin, a colorant and a releasing agent to form first fine particles, aggregating the first fine particles to form aggregated particles as a core, aggregating second fine particles containing a polyester resin onto the core to form a shell.

Abstract: A method for manufacturing a developing agent by mixing a resin having a dissociable functional group and an aqueous medium, subjecting the mixture to mechanical shearing, finely pulverizing the pulverized mixture to form resin microparticles, adding a dispersion of colorant particles, causing the resin microparticles and colorant particles to agglomerate, and forming toner particles.

Abstract: A method for producing a developing agent, includes preparing a dispersion of particles containing a binder resin and a coloring agent and forming toner particles by aggregating and fusing the particles, in which the number of coarse particles having a particle size of 0.6 ?m or larger after the solid concentration of the dispersion of particles is adjusted to 1 ppm is less than 3,000 per ?L.

Abstract: A method for producing a developing agent including heating a dispersion of a toner particle material containing a binder resin fine particle, a coloring agent particle and a dispersion medium at a temperature of a glass transition point of the binder resin or higher and adding a coagulating agent in the heated dispersion of a toner particle material to coagulate a toner material containing the binder resin fine particle and the coloring agent particle, thereby forming a coagulated particle is disclosed.

Abstract: A coarse particle containing a polyester based resin and a coloring agent is added in an aqueous medium containing a surfactant, a basic substance and an inorganic water-soluble electrolyte, and dispersion and coagulation are carried out to form a toner particle.

Abstract: According to one embodiment, a color erasable coloring material containing a binder resin, and dispersed therein, a color developable compound and a color developing agent is provided. The color developing agent to be used in the coloring material contains at least an aminohydroxy derivative. The aminohydroxy derivative is obtained by subjecting a starting material selected from a benzene ring compound having a hydroxy group and a heterocyclic compound having a hydroxy group to nitration, hydrogenation, and alkylation.

Abstract: It is intended to provide a method includes the step of forming agglomerated particles by agglomerating fine particulate mixture containing a binder resin and a colorant. In the step of forming agglomerated particles, a cationic organic coagulating agent having an average molecular weight of from 1000 to 100000 is added to a liquid dispersion containing fine particles.

Abstract: According to one embodiment, a method for producing a developing agent including aggregating fine particles of a toner material containing a binder resin and a coloring agent in a dispersion liquid in which the fine particles are dispersed in an aqueous medium to form aggregated particles, and washing the aggregated particles and drying the washed aggregated particles, forming toner particles is provided. An electrical conductivity of the toner particles is measured by a toner electrical conductivity evaluation method. A sample toner is prepared by adhering an additive to surfaces of the toner particles, and a content ratio of a sodium element to a carbon element in a region to which the additive is not adhered of the toner is measured. The washing of the toner particles is repeated until each of the measurement values becomes a predetermined reference value or less.