Abstract: According to one embodiment, a decolorizable water-based inkjet ink includes a color material, a solvent, and a nonionic surfactant. The color material contains a color developable compound and a color developing agent, and the solvent contains water and a water-soluble organic solvent. The nonionic surfactant is contained in the ink in an amount of 5 wt % or more of the total amount of the solvent.

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: An electrophotographic toner, which is decolorized by heating and a glossiness after decolorization of which is less than 10, comprising an electron donating color former compound, an electron accepting color developing agent, and a polyester binder resin.

Abstract: According to one embodiment, a method of manufacturing a color erasable developing agent including preparing a dispersion containing a fine particle containing a leuco dye and a developer, a fine particle containing a color erasing agent, a toner binder resin fine particle and a medium, aggregating the fine particles in the medium, and heat fusing the aggregate to form a toner particle is provided.

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: An erasable toner is prepared by mixing colored particles containing at least a color former compound, a color developer agent and a binder resin with de-coloring particles having a melting point higher than the fixing temperature of the colored particles. By using this toner, a colored image is formed by electrostatically transferring a toner image onto a medium, and heating the toner image at a temperature lower than the melting point of the de-coloring particles to form a fixed toner image in a color developed state, and the color of the fixed image is erased by heating the image to a temperature not lower than the melting point of the de-coloring particles. In this toner, the color developing function and the color erasing function are assigned to different particles so that the functions are separated from each other, and therefore, the formation of an image in a color developed state and the erasure thereof can be reliably and promptly achieved.

Abstract: Disclosed is a decolorable toner containing a binder resin and a coloring agent which contains a color former compound and a color developing agent and has a capsule structure such that it is covered with an outer shell, and having a volume average particle diameter of from 5.0 to 15.0 ?m and a number-based particle size distribution CV of 35% or less.

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: An electrophotographic toner contains an electron donating color former compound, an electron accepting color developing agent, and a polyester binder resin having a weight average molecular weight Mw of 6000 or more and 25000 or less, and the toner is decolorized by heating.

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.

Abstract: The dispersion liquid including toner material particles is introduced into a mechanical shearing device including a heating unit, a mechanical shearing unit, and a cooling unit, heated to a temperature not lower than the glass transition temperature of the polyester resin under a condition that satisfies the following relationship (1), subjected to mechanical shearing, and thereafter cooled, whereby fine particles are obtained. ?2<log ((A+B)/C)<2??(1) With the proviso that a volume of a portion in which the dispersion liquid flows in the heating unit and the mechanical shearing unit is expressed as A cc, a volume of a portion in which the dispersion liquid flows in the cooling unit is expressed as B cc, and a flow rate of the dispersion liquid is expressed as C cc/min.

Abstract: According to one embodiment, a method for producing a developing agent includes pulverizing a mixture in the form of coarse particles of a toner material including a coloring agent and a binder resin by mechanical shearing, aggregating and fusing the resulting fine particles. The solid content concentration in a dispersion liquid including the aggregated particles is from 5.0% to 40.0%, the volume average particle diameter of the aggregated particles is from 1.0 ?m to 10.0 ?m, and the ratio of the standard deviation to the volume average particle diameter is 30.0% or less.

Abstract: A developing agent including a toner particle obtained by using a dispersion containing a solvent, a granular mixed compound having a binder resin and a coloring agent dispersed in the solvent, and, as an additive to disperse a compound, a combination of a surfactant and a basic compound or a combination of a sulfone-based surfactant and a polycarboxylic acid-based surfactant, wherein the additive remaining in the developing agent is within a predetermine range.

Abstract: According to one embodiment, a method for producing a color erasable recording material includes dispersing a granulated mixture of a color erasable recording material in an aqueous medium to form an aqueous dispersion liquid, and subjecting the dispersion liquid to a high-pressure pulverizer at a temperature not lower than the melting point of a color erasing agent to pulverize the granulated mixture in the dispersion liquid, thereby obtaining a particulate color erasable recording material having a volume average particle diameter smaller than that of the granulated mixture.

Abstract: Disclosed is an decolorizable electrophotographic toner, containing a binder resin, an electron-donating color-developable agent, and a wax having a color-developing action and having an acid value of 60 mgKOH/g or more.

Abstract: As a first dispersion liquid containing first fine particles and a second dispersion liquid containing second fine particles, those satisfy the relationship represented by the following formula (1) are used, and these two dispersion liquids are mixed with each other, and an aggregating agent and a pH adjusting agent are added thereto in sequence, whereby encapsulation is achieved by selective formation of core particles through aggregation of the first fine particles and shells through aggregation of the second fine particles. 15 mV?|Z2?Z1|?5 mV??(1) In the formula, Z1 and Z2 represent zeta potentials of the first dispersion liquid and the second dispersion liquid, respectively, measured when aluminum sulfate is added to each dispersion liquid in an amount of 1% by weight based on the solid content in each dispersion liquid.

Abstract: A method for producing a developing agent, wherein in the formation of aggregated particles, particles in a dispersion liquid have a volume average particle diameter of 2 ?m or less when the pH of the dispersion liquid is 7, and also the pH of the dispersion liquid is from 3.0 to 6.9 when the zeta potential of the particles is ?30 mV.