Abstract: There are provided a release agent capable of attaining a toner excellent in an anti-offset property and an anti-filming property, without detaching from a kneaded mass even in a case of granulating by heating a dispersion medium containing the kneaded mass, as well as a toner using the release agent and a manufacturing method thereof. A release agent containing a compatible site having compatibility with the binder resin and a releasing site chemically bonded with the compatible site and having the releasing ability is used as the release agent when preparing a kneaded mass by melt-kneading at least a binder resin, a colorant, and a release agent, whereby detachment of the release agent from the kneaded mass can be prevented in producing particles of kneaded mass as the toner particles by mixing the kneaded mass to an aqueous medium prepared and heating and stirring them.

Abstract: A toner containing a lignin resin, a carbon-neutral biomass polymer having a low environmental load and taking global environmental protection into account, as a constitutional component of a binder resin, and having a wide fixing non-offset range and an excellent fixing property, is provided. The toner contains at least a binder resin, a colorant, and a release agent. Furthermore, in the toner, the binder resin includes a resin A that is a lignin resin and a resin B that is another resin component, and the resin B has a peak top molecular weight of 103 to 104 and an acid number of 20 or less.

Abstract: There is provided a method of manufacturing a toner, using a shearing force for granulation, in which bubbles are prevented from arising upon application of the shearing force, thus manufacturing a diameter-reduced toner having a particle diameter of about 5 ?m which is favorable for enhancement in definition and resolution of images. Upon granulating after a kneaded product of toner raw material is mixed with water dispersion, an interior part of granulating system is heated and pressurized and moreover, both of the shearing force and collision force are applied to the kneaded product of toner raw material by use of a high-speed rotating dispersion type granulator composed of a cylindrical pressure-resistant container, a spinning rotor, following screens, and a fixed screen.

Abstract: A toner is provided. The toner includes toner particles, and silica particles and inorganic fine particles that are externally added to the toner particles, the inorganic fine particles having an average primary particle size smaller than that of the silica particles. The toner particles have a shape factor SF-1 of 130 or more and 140 or less, a shape factor SF-2 of 120 or more and 130 or less, and a volume average particle size of 5 ?m or more and 8 ?m or less. The silica particles have an average primary particle size of 80 nm or more and 150 nm or less, and an amount of water of 1.5% by weight or less. A particle size distribution of the silica particles is a logarithmic normal distribution, and a value of geometric standard deviation ?g of the particle size of the silica particles is less than 1.30.

Abstract: In a method of manufacturing a toner in which toner particles are obtained by mixing resin particles and at least a colorant with each other to be coagulated, and heating an obtained coagulated product, binder resin is granulated into fine particles by a granulating method including a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry containing coarse particles of binder resin obtained by way of the coarse particle preparing step and the slurry preparing step is made to pass under heat and pressure through a pressure-resistant nozzle whereby the coarse particles of binder resin are pulverized into resin particles. By providing the cooling step and the depressurizing step immediately after the pulverizing step, the resin particles are prevented from coarsening.

Abstract: An image forming apparatus having excellent cleaning property for an electrophotographic photoreceptor and capable of forming a high-quality, high-resolution image. A surface free energy (?) of a photoreceptor (2), which is provided in the image forming apparatus (1), is set to 20 to 35 mN/m. A volume average diameter of toner particles included in a developer stored in a developing unit (29) to develop an electrostatic latent image and form a toner image is set to 4-7 ?m When ? of the photoreceptor (2) is set to within a small range as the particle size of toner is reduced, even small-particle-size toner having increased specific surface area and largely affected by a inter-molecular force is limited in adhesion to the surface of the photoreceptor (2) to provide a good cleaning property and a high-quality image can be formed.

Abstract: Resin particles containing at least binding resin and wax particles having a diameter of 30 to 600 nm are coagulated, and a resulting coagulated product is heated. Such wax particles are manufactured, for example, by way of a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry of wax coarse particles obtained by way of the coarse particle preparing step and the slurry preparing step is directed under heat and pressure through a pressure-resistant nozzle whereby the wax coarse particles are pulverized into the wax particles at the pulverizing step. The cooling step and the depressurizing step are disposed just after the pulverizing step to prevent the wax particles from coarsening.

Abstract: There is provided a method of manufacturing coalesced resin particles for obtaining coalesced resin particles by coalescing aggregated resin particles in a grain boundary-free state in a short period of time while keeping a grain size distribution within a narrow range. In a coalescence process, a slurry of aggregated resin particles is flowed through an inside of a pipe under predetermined heating and pressurizing conditions. In a before-cooling decompression process, a slurry of coalesced resin particles flowing through the inside of the pipe in a heat and pressure-applied state is subjected to pressure reduction before it is cooled down to a predetermined temperature in a cooling process. Then, in a decompression process, a coalesced resin particle slurry that has been cooled in the cooling process while being flowed through the inside of the pipe is decompressed to an atmospheric pressure.

Abstract: A toner of excellent anti-hot offsetting property, with no variety of the charging performance and suitable as a toner for the development of electrostatic images, and a manufacturing method thereof are provided. At first, a crosslinked resin at least containing a tetrahydrofuran insoluble component and a colorant are dry-kneaded. Next, the obtained kneaded resin product is mixed with an aqueous dispersant solution prepared in advance and they are heated, to form colorant-containing resin particles in a liquid mixture of the kneaded resin product and the aqueous dispersant solution. Then, the liquid mixture is cooled and the colorant-containing resin particles are separated from the liquid mixture.

Abstract: There are provided an economical method capable of obtaining very small resin particles, in particular, resin particles; resin particles produced by the method; a toner and developer containing the resin particles; a developing device; and an image forming apparatus. Spherical particles are produced according to a producing method of spherical particles including a pulverizing step. In the pulverizing step, a dispersion liquid of coarse particles of material to be processed, which includes a polymer dispersant and coarse particles of material to be processed dispersed in a liquid medium is passed through a high-pressure homogenizer having a stepwise pressure release mechanism and thereby coarse particles of material to be processed contained in the dispersion liquid are milled under conditions where the melt viscosity of the dispersion liquid at a time point of passing the nozzle portion of the high-pressure homogenizer may be 5000 cP or less.

Abstract: The toner includes a plurality of toner particles containing a binder resin and a colorant. In toner particles, according to measurement by a flow particle image analyzer, the content of small size particles having a circle-equivalent diameter of 0.5 to 2.0 ?m is 5% by number or less based on the entire toner particles, the content of medium size particles having a circle-equivalent diameter of more than 2.0 ?m and 4.0 ?m or less is 20% by number or more and 30% by number or less based on the entire toner particles, and the content of large size particles having a circle-equivalent diameter of more than 4.0 ?m and 6.0 ?m or less is 50% by number or more and 70% by number or less based on the entire toner particles, and the shape factor of the toner particles SF1 is 130 or more and 140 or less.

Abstract: A toner is manufactured by way of a coarse particle preparing step, a slurry preparing step, a pulverizing step, a cooling step, and a depressurizing step. Slurry of toner coarse particles obtained by way of the coarse particle preparing step and the slurry preparing step is made to pass under heat and pressure through a pressure-resistant nozzle whereby toner coarse particles are pulverized into diameter-reduced toner particles. By providing the cooling step immediately after the pulverizing step, dispersion of wax component into the toner particles is promoted. And by further providing the depressurizing step, bubbling and coarsening of the toner particles due to the bubbling are prevented. By so doing, there is obtained a diameter-reduced toner particle in which wax is evenly dispersed and which does not cause bleeding out.

Abstract: According to the method of producing toner, toner is produced by (i) forming particles of a pigmented resin by applying shear stress to a mixture of a pigmented resin composition, an organic solvent, a polymer dispersing agent, and a hydrophobic medium, the organic solvent being capable of reducing viscosity of the pigmented resin composition, and said polymer dispersing agent having a glass transition point in a range of 50° C. to 80° C. and an SP value in a range of 8.5 to 10, (ii) distilling off the organic solvent, and (iii) separating the toner from the hydrophobic medium and drying the toner. With the above arrangement, the method makes it possible to (i) easily downsize toner particle without causing thermal decomposition of a resin or separation of a release agent, and (ii) produce toner that is small in particle size, excellent in humidity-resistance, and less likely to aggregate.

Abstract: A method of manufacturing toner particles capable of decreasing the manufacturing costs by simplifying the manufacturing apparatus and by decreasing the number of the steps, as well as to provide toner particles, a two-component developer, a developing apparatus and an image forming apparatus are provided. A high-pressure homogenizer is constituted by a tank, a feed pump, a high-pressure pump, a heat exchanger, a nozzle, a first depressurizing module, a cooling unit, a second depressurizing module and a take-out port arranged in this order. A flow path constituted in the first depressurizing module has a straight portion tilted with respect to a direction in which the aqueous slurry passes and a portion for relaxing the flow of the aqueous slurry.

Abstract: Method of manufacturing resin particles capable of manufacturing resin particles of controlled particle size stably and efficiently by removing bubbles from the surface of a molten kneaded product as the raw material for resin particles thereby sufficiently ensuring action sites for a surfactant on the surface of the molten kneaded product, is provided. The method includes a coarsely-pulverizing step of pressurizing a mixture of a molten kneaded product containing a synthetic resin and an aqueous medium containing a surfactant to 15 MPa to 120 MPa thereby removing bubbles attached to the molten kneaded product containing the synthetic resin, and a finely-granulating step of finely granulating, by a high pressure homogenizer method, an aqueous slurry containing coarse particles of a molten kneaded product passing through a pressure proof nozzle in the coarsely-pulverizing step and in a state where bubbles attached to the surface are removed.

Abstract: A toner capable of forming high quality images of excellent image reproducibility at high definition and high resolution, being decreased for the bleed-out of a wax ingredient to the surface, causing less filming to a photoreceptor and offset phenomenon in a high temperature region, is provided. The toner is manufactured by a method including a preliminary pulverizing step of pulverizing a melt-kneaded product of toner raw materials in a liquid to obtain a coarse powder slurry containing a coarse toner powder, a finely pulverizing step of passing the coarse powder slurry through a pressure resistant nozzle under heating and pressurization thereby further pulverizing the coarse toner powder to obtain a fine powder slurry containing a fine toner powder and in a heated and pressurized state, a cooling step of cooling the fine powder slurry, and a depressurizing step of depressurizing the fine powder slurry.

Abstract: A method of manufacturing a toner in which uneven distribution of toner ingredients by subjecting them to fine dispersion is prevented and which is excellent in transferability, cleaning properties, anti-filming properties, anti-blocking properties, high-temperature offset resisting properties and transparency is provided. Melt-kneaded substances include binder resins, colorants and release agents, respectively. The colorant and the release agent are dispersed in the binder resin. The melt-kneaded substance is negatively charged by an anionic dispersant, whereas the melt-kneaded substance is positively charged by a cationic dispersant. An aggregate is formed by heteroaggregation of the melt-kneaded substances. The aggregate is fused by heating and formed into a spherical toner.

Abstract: A toner composed of small particles excellent in a cleaning property, a transferring property, and charge uniformity is provided as well as a method of manufacturing the toner, and two-component developer, developing device, and image forming apparatus using the toner. The toner contains binder resin and colorant, and includes a particle which has an outline having one or more and three or less bending points in its projection image on a plane. The toner thus contains a non-spherical particle and therefore is caught easily by a cleaning blade as well as coming into point-contact with a to-be-transferred member, therefore being capable of having both of cleaning property and transferring property.

Abstract: In a raw material mixing step, toner raw materials containing polymerizable monomers, colorant, and a release agent are mixed. In an emulsifying step, the mixture is emulsified under pressure to obtain a polymerizable composition. In a cooling step, the polymerizable composition is cooled down. In a depressurizing step, the polymerizable composition cooled down is depressurized. The polymerizable composition thus obtained has the colorant and the release agent evenly and finely dispersed therein. In a polymerizing step, the polymerizable composition is subjected to polymerization reaction. Toner particles are thus obtained which have uniform final sizes and exhibit a sharp particle size distribution.

Abstract: A method of manufacturing aggregate particles capable of obtaining aggregate particles having high mechanical strength, small particle size, with narrow particle size distribution width by preventing interfusion of bubbles in the aggregate particles during stirring is provided. Aggregate particles are manufactured by stirring a resin particle slurry including resin particles dispersed in an aqueous medium and contained in a stirring vessel by a stirring section having a impeller and two or more screen members disposed so as to surround the impeller in the stirring vessel and each formed with a plurality of slits and aggregating the resin particles.