59results about How to "Sharp particle size distribution" patented technology

The object of the present invention is to provide a developer having a sharp charge amount distribution and bringing out high-quality image without substantially smearing a charging unit, developing units, a photoconductor, and an intermediate transferring member by the developer, namely, a developer capable of providing an appropriate image density and exhibiting extremely little background smear even when used over a long period of time and repeatedly used for a number of sheets of paper as well as to provide an image forming apparatus for electrophotography using the developer.

Provided is a method of producing a toner including the steps of: mixing a resin solution comprising a resin R, a colorant, and an organic solvent, a resin fine particle comprising a resin S containing an element α, and carbon dioxide to form a droplet having a surface covered with the resin fine particle; introducing carbon dioxide in a liquid state and pressurizing to extract the organic solvent in the droplet; and removing the extracted organic solvent together with the carbon dioxide to provide a toner particle. In the method of producing a toner, when the resin fine particle is treated with the carbon dioxide in a liquid state, a change in amount of the element α on the surface of the resin fine particle after the treatment as compared to the amount before the treatment falls within a specific range.

A method of producing a toner including the steps of: mixing resin fine particles, an organic solvent, and a resin R with a dispersion medium containing carbon dioxide, to prepare a dispersion of resin R-containing droplets; and removing the organic solvent by flowing carbon dioxide, wherein the resin fine particles contain one or more resins that have a partial structure A, B, and C, and are soluble in chloroform; the SP value of the partial structure A, the resin R, and the partial structure B satisfy particular relationships; a resin A constituted of the partial structure A and a resin B constituted of the partial structure B are soluble in the organic solvent; and a resin C constituted of the partial structure C is insoluble in the organic solvent.

The invention aims at providing a process for the production of highly crystalline silver powder which comprises silver particles falling within the fine particle region and has an excellent particle size distribution and highly crystalline silver powder obtained by the process. The aim is attained by a process for the production of highly crystalline silver powder which is characterized by preparing the first aqueous solution containing gelatin, silver nitrate and nitric acid and having a temperature of 45 to 55 C and the second aqueous solution containing erythorbic acid and / or ascorbic acid and a water-soluble organic acid, adding the second aqueous solution mildly to the first aqueous solution, stirring the mixed solution after the completion of the addition to form silver particles through particle growth, allowing the resulting system to stand to settle the silver particles, removing the supernatant, and then subjecting the remainder to filtration and washing to recover the silver particles.

An object of the present invention is to provide a spherical toner that has a sharp particle size distribution and a small particle diameter. This is a capsule-type toner that exhibits an excellent low-temperature fixability, while at the same time having a high offset resistance and excellent charging properties and having the ability to provide a high-quality image in which the characters, lines, and dots are precisely defined. The object is achieved by a toner comprising a toner particle that comprises at least (a) resin having polyester as the main component, colorant, wax, and (b) urethane resin, wherein the hydroxyl value per specific surface area of the toner particle is fall into the specific range, and wherein a Tg(0.5) and a Tg(4.0)-Tg(0.5) of the toner fall into specific range.

It is an object of the present invention to provide a method for producing gold colloid having a targeted particle size, a sharp particle size distribution and a uniform and perfect spherical shape. The present invention relates to a method for producing gold colloid including a nucleation step of forming nuclear colloidal particles by adding a first reducing agent to a first gold salt solution; and a growth step of growing nuclear colloid by adding a second gold salt and a second reducing agent to the solution of the nuclear colloidal particles, characterized in that the growth step is performed at least once; a citrate is used as the first reducing agent and an ascorbate is used as the second reducing agent; and the addition of the ascorbate in the growth step is performed simultaneously with addition of the second gold salt. According to the method for producing gold colloid of the present invention, gold colloid having a sharp particle size distribution and a uniform and perfect spherical shape can be obtained.

To provide a toner production process in which at least radically polymerizable monomers are polymerized in at least one of a supercritical fluid and a subcritical fluid to thereby produce toner particles, wherein a polymer of the radically polymerizable monomers is insoluble in at least one of the supercritical fluid and the subcritical fluid.

To provide a method for producing a toner in which at least monomers are polymerized in at least one of a supercritical fluid and a subcritical fluid to thereby produce toner particles, wherein at least one of the supercritical fluid and the subcritical fluid contains a fluorine-containing surfactant, and a polymer resulted from polymerization of the monomers is insoluble in at least one of the supercritical fluid and the subcritical fluid, and provide a toner produced by the method for producing the toner.

In a process for producing toner particles by dispersing in an aqueous medium a polymerizable monomer composition containing at least a polymerizable monomer and a colorant and carrying out polymerization by the use of a polymerization initiator, the concentration of alcohol having 4 to 6 carbon atoms in the aqueous medium is so adjusted as to be from 500 ppm to 2,000 ppm when the polymerization conversion of the polymerizable monomer composition is 30%, and to be from 2,300 ppm to 10,000 ppm when the polymerization conversion of the polymerizable monomer composition is 97%.

The present invention aims to improve the cycle properties of a nonaqueous electrolyte secondary cell obtained using the nickel-cobalt compound hydroxide as the precursor. In the present invention, a slurry contains a nickel-cobalt compound hydroxide that is obtained by reacting and continuously feeding to a reactor an aqueous solution containing at least nickel and cobalt, an aqueous solution that serves as an ammonium ion donor, and an aqueous caustic alkali solution. The slurry is continuously extracted and the slurry is separated by grading into large particle diameter portions and small particle diameter portions. The small particle diameter portion is continuously circulated back to the reactor. The resulting nickel-cobalt compound hydroxide is represented by the general formula Ni1-x-yCoxMy (OH)2 (where 0.05 <= x <= 0.50, 0 <= y <= 0.10, 0.05 <= x + y <= 0.50, M is at least one metal element selected from Al, Mg, Mn, Ti, Fe, Cu, Zn, and Ga), wherein the correlations of (D50-D10) / D50 <= 0.30 and (D90-D50) / D50 <= 0.30 are established between D10, D50, and D90.

There are provided a copper powder for conductive paste, which comprises monodisperse and spherical fine copper particles having a sharp particle size distribution and containing no coarse particles and which can form a thinner electrode film while avoiding a bad influence on electric characteristics thereof, and a method for stably producing such a copper powder for conductive paste. After copper is complexed by adding a complexing agent to an aqueous solution containing copper while blowing air into the solution, the blowing of air is stopped, and then, a reducing agent is added to the solution to deposit copper particles by reduction.

A magenta toner characterized by satisfying, in DSC measurement, 40.0≦Tg(0.5)≦60.0 and 2.0≦Tg(4.0)−Tg(0.5)≦10.0, wherein when preparing a solution of which the magenta toner is dissolved in ethyl acetate, and defined the concentration of the thereof as Cm1 (mg / ml), and the light absorbance thereof at a wavelength of 538 nm as A(ethyl acetate)538, the ratio of A(ethyl acetate)538 to Cm1 satisfies the formula, A(ethyl acetate)538 / Cm1<0.15, and, when preparing a solution of which the magenta toner is dissolved in chloroform, and defined the concentration of the thereof as Cm2 (mg / ml), and the light absorbance thereof at a wavelength of 538 nm as A(chloroform)538, the ratio of A(chloroform)538 to Cm2 satisfies the formula, 2.00<A(chloroform)538 / Cm2<6.55.