JP4337611B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

The present invention relates to a method for producing an electrostatic charge image developing toner.

  In the field of electrophotography, high image quality has been studied from various angles, and in particular, the recognition that toner particle size reduction, monodispersion, and spheroidization are extremely effective is increasing. A toner (also referred to as a chemical toner) produced by a polymerization method can achieve a smaller particle size and spheroidization of toner particles than a conventional pulverized toner.

  However, the resin for the polymerized toner is limited to a resin using an addition polymerization type polymerizable monomer or a condensation polymerization type polymerizable monomer. In particular, it is extremely difficult to produce a toner using a polyester resin excellent in sharp melt property by a polymerization method.

  In addition, the toner production method using the emulsification dispersion method (solution suspension method) has few limitations on the resin that can be used, the toner particles can be easily formed into a sphere, and a toner using a polyester resin can also be produced. is there. However, in order to obtain a toner having a small particle size that is resistant to crushing or the like, it is necessary to give a very strong mechanical shear, and there is a limit in narrowing the particle size distribution of the obtained toner particles.

  As a manufacturing method for narrowing the particle size distribution of toner particles, toner manufacturing examples using a droplet discharge device such as an ink jet printer have been reported (for example, see Patent Documents 1, 2, and 3).

  Specifically, it is a toner manufacturing method in which a toner composition dissolved and dispersed in an organic solvent is discharged from a nozzle, and then the discharged toner composition is solidified to form particles.

  Also, a composition comprising a polymerizable monomer in which a colorant is dispersed is ejected from a nozzle to form a dispersion of fine droplets of the polymerizable monomer composition, and then the fine droplets are polymerized to form particles. Production examples have been reported (for example, see Patent Document 4).

  In addition, after a colored resin in which at least a colorant is dispersed or dissolved in a heat-meltable resin is melted, it is discharged from a nozzle to form droplet-shaped fine particles, and then the droplet-shaped fine particles are cooled and solidified to form a granular shape. A toner production example is reported (for example, see Patent Document 5).

  In these examples, since the toner is manufactured by utilizing the particle diameters of the droplet particles discharged from the nozzles, it is possible to obtain a toner having a narrow particle size distribution.

  However, when trying to reduce the particle size of the toner, the diameter of the nozzle also decreases, and there is a problem that the nozzle is clogged with the aggregate of the colorant and the large particle size colorant contained in the discharged composition, There was a problem in stably producing a toner having a small particle size and a narrow particle size distribution.

As described above, it has not yet been achieved to stably obtain a toner having a small particle size and a narrow particle size distribution.
JP 2003-262976 A Japanese Patent Laid-Open No. 2003-262977 JP 2003-280236 A JP-A-7-281480 JP 2002-275272 A

The present invention has been made in view of the above problems. That is, the present invention provides a toner for developing an electrostatic charge image that can stably produce a toner for developing an electrostatic charge image (hereinafter, also simply referred to as toner) capable of obtaining a print image having a high density, little fog, and excellent resolution. It is intended to provide a method .

  The object of the present invention is achieved by the following configurations.

1. A droplet of a resin solution in which a resin is dissolved in a solvent , the nozzle shape is substantially circular, the nozzle diameter is 100 nm to 5 μm , and the pulsation is caused by the action of pressure, electric force, magnetic force, gas, or bubble generation. a nozzle head that utilizes, in an aqueous medium which is stirred in the strong enough to not break the droplet, ejected by the step of producing a dispersion having droplets of the resin solution, the dispersion process and method for producing a toner for developing electrostatic images, which comprises manufactured through a step of at least aggregating / fusion bonding the colorant particles and the resin particles solvent is removed to prepare a resin particle from.

2. The droplets of the polymerizable monomer, a substantially circular nozzle shape, a nozzle diameter of 100 nm to, utilize pressure, electrical forces, magnetic forces, the pulsation caused by the action of either the generation of gas or bubbles a nozzle head, generating the droplets in a solution which does not dissolve the polymerizable monomer are stirred in the strong enough to not break, discharge, the dispersion with droplets of the polymerizable monomer a step of the step of preparing a resin fine particles by polymerizing said droplets, for developing an electrostatic image, characterized by manufactured through a step of at least aggregating / fusion bonding the colorant particles and the fine resin particles Toner manufacturing method.

Narrow particle size distribution with a small particle size, is to provide a toner production method capable of stably manufacturing a belt toner quality toner image can not be obtained.

Toner over manufacturing method of the first aspect of the invention, discharged into an aqueous medium nozzle diameter nozzle shape with a substantially circular ejection device a resin solution obtained by dissolving resin in a solvent is stirred from a nozzle of 100 nm to, After producing a dispersion having droplets of a resin solution, a resin fine particle is produced by removing the solvent from the dispersion, and the resin fine particle and at least the colorant particle are aggregated / fused to produce. It is characterized by.

Toner over the manufacturing method of the second invention, a solution nozzle shape of the ejection device polymerizable monomers are stirred nozzle diameter substantially circular does not dissolve the polymerizable monomer from the nozzles of 100nm~5μm To produce a dispersion liquid having droplets of a polymerizable monomer, and then polymerizing the droplets to produce resin fine particles. The resin fine particles and at least the colorant particles are aggregated / heat-sealed. It is characterized by manufacturing .

This onset Ming preparative toner manufacturing method may be a particle size distribution with a small particle diameter is produced stably narrow toner has a high density when an image formed using the toner, fogging less, excellent resolution Prints can be obtained.

  A resin solution dissolved in a solvent is discharged from a nozzle into a liquid to produce fine resin particles, or a polymerizable monomer is discharged from a nozzle into a liquid to form droplets of a polymerizable monomer and then polymerized. In the method of generating resin fine particles, resin fine particles having a target particle size and particle size distribution can be obtained by controlling the shape of the nozzle, the discharge pressure, and the like. When a toner is produced using the resin fine particles, a toner having a small diameter and a uniform particle size distribution can be obtained.

  In the first and second inventions, since the colorant essential as a toner component is not ejected from the nozzle, nozzle clogging caused by the colorant does not occur, and the resin fine particles are prepared in a stable state. Can do.

  Here, the average particle size and particle size distribution of the toner particles used in the present invention, the average circularity, the measurement method of the average particle size of the resin fine particles, and preferred values thereof will be described.

<Particle size and particle size distribution of toner particles>
The average particle diameter of the toner particles is determined by measuring with “Coulter Counter TAII Type” or “Coulter Multisizer” (manufactured by Coulter Co.). From the measurement results, the ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dp) is calculated and determined.

  The particle size distribution of the toner particles is evaluated by the value of volume average particle size (Dv) / number average particle size (Dp), and the smaller this value, the narrower the particle size distribution.

  The volume average particle size of the toner particles is preferably 3 to 7 μm. The volume average particle diameter (Dv) / number average particle diameter (Dp) of the toner particles is preferably 1.00 to 1.15.

<Average circularity of toner particles>
The average circularity of the toner particles is determined by measurement using “FPIA-2000” (manufactured by Sysmex Corporation). Here, the average circularity is
Average circularity = defined by the circumference of a circle equal to the projected area of the particle / the circumference of the projected particle image. The average circularity of the toner particles is preferably 0.90 to 1.00.

<Average particle diameter of resin fine particles>
The particle size of the resin fine particles in the dispersion is determined by measuring with “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.). The volume average particle diameter of the resin fine particles is preferably 50 to 1000 nm.

  The volume average particle size / number average particle size of the resin fine particles is preferably 1.00 to 1.30, and more preferably 1.00 to 1.15.

  When an image is formed using toner prepared by controlling the average particle size and particle size distribution of the toner particles, the average circularity, and the average particle size of the resin fine particles within the above ranges, the image has high density, little fog, and resolution. Excellent prints can be obtained.

  Next, a method for producing resin fine particles and a method for producing toner will be described.

1. 1. Method for producing resin fine particles 1-1. Method for Producing Resin Fine Particles of the First Invention In the first invention, the resin fine particles are obtained by discharging a resin solution obtained by dissolving a resin in an organic solvent from a nozzle of a discharge device into a solution that does not dissolve the resin. It is obtained by forming a dispersion having droplets and then removing the organic solvent.

  As a discharge device that discharges the resin solution, a device having a structure similar to the head of an ink jet printer can be used. The resin solution dissolved in the solvent is sent to the nozzle head of the discharge device, and droplets of the resin solution are discharged from the nozzle head utilizing the pulsation caused by the action of the piezoelectric element. For ejection, a nozzle head using an action such as generation of pressure, electric force, magnetic force, or gas or bubbles can also be used. In addition, a heater for heating may be attached to the nozzle head to control the temperature of the resin solution in the nozzle and at the nozzle discharge section. When a resin solution in which a resin is dissolved in an organic solvent is discharged from a nozzle, if the viscosity of the molten solution is too high, it becomes difficult to discharge the resin solution. It is preferable to reduce the viscosity of the solution.

  The shape of the nozzle discharge portion is not particularly limited, but is preferably substantially circular in order to increase the sphericity of the resin fine particles.

  The nozzle diameter of the nozzle head needs to be appropriately selected according to the production conditions such as the type of resin, the viscosity of the resin solution, and the desired particle diameter, and is preferably 100 nm to 5 μm.

  The resin solution dissolved in the organic solvent is preferably used after being filtered with a filter smaller than the nozzle diameter of the nozzle head for the purpose of preventing clogging of the nozzle.

  The resin solution dissolved in the organic solvent is discharged as droplets from a nozzle into a solution (aqueous medium) that does not dissolve the resin, and the discharged droplets become a dispersion liquid dispersed in the solution. In order to prevent the droplets in the dispersion from fusing, it is preferable that the solution is stirred with a strength that does not break the droplets.

  When the discharge of the resin solution is completed, the dispersion liquid in which the droplets are dispersed is heated while reducing the pressure as necessary to remove the organic solvent, thereby obtaining a dispersion liquid in which the resin fine particles are dispersed.

  The resin that can be used in the first invention is not particularly limited as long as it is generally used as a binder for toners. For example, polystyrene resin, poly (meth) acrylic resin, polyolefin Thermoplastic resins such as resin, polyamide resin, polycarbonate resin, polyether resin, polysulfone resin, polyester resin, and epoxy resin can be used. Furthermore, not only those in a complete polymer state as in thermoplasticity but also those containing an oligomer or prepolymer, a crosslinking agent, etc. as in a thermosetting resin can be used.

  Examples of the organic solvent for dissolving the resin include dichloromethane, dichloroethane, trichloromethane, trichloroethane, methyl acetate, ethyl acetate, propyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate, methyl propionate, ethyl propionate, and diethyl ether. , Dipropyl ether, benzene, toluene, xylene, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran and the like may be used alone or in admixture.

  The aqueous medium is a poor solvent or an insoluble solvent that does not substantially dissolve the resin. Preferable examples include water, a mixed medium of water and a water-soluble organic solvent, and the like. Examples of the water-soluble organic solvent include alcohols, ketones, glycol ethers and the like.

  A dispersion stabilizer is usually added to the aqueous medium in order to prevent aggregation of dispersed droplets. A known surfactant can be used as the dispersion stabilizer, and a dispersion stabilizer selected from a cationic surfactant, an anionic surfactant, a nonionic surfactant, and the like can be used. Two or more of these surfactants may be used in combination. The dispersion stabilizer can also be added to a dispersion such as a colorant or an offset preventing agent.

  Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and the like.

  Specific examples of the nonionic surfactant include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, norylphenyl polyoxyethylene ether, ralyl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, styrylphenyl poly Examples thereof include oxyethylene ether and monodecanoyl sucrose. Of these, anionic surfactants and / or nonionic surfactants are preferred.

1-2. Resin fine particle manufacturing method of the second invention In the second invention, the resin fine particles are produced by discharging a polymerizable monomer into an aqueous medium from a nozzle to form droplets and then polymerizing the droplets. can get.

  As the discharge device for discharging the polymerizable monomer from the nozzle, one having the same structure as that of the first invention can be used. Further, as the aqueous medium from which the droplets of the polymerizable monomer are discharged, the same one as in the first invention can be used.

  The polymerizable monomer is preferably used after being filtered through a filter smaller than the diameter of the nozzle discharge portion for the purpose of preventing clogging of the nozzle.

  As the polymerizable monomer, conventionally, an addition polymerization type polymerizable monomer or a condensation polymerization type polymerizable monomer generally used for constituting a binder resin of a toner produced by a polymerization method is used. The body is mentioned. In the present invention, an addition polymerization type polymerizable monomer is preferably used. Examples of such materials include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p. -Ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn- Styrene such as decylstyrene and pn-dodecylstyrene and derivatives thereof; Ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; Unsaturated polyenes such as butadiene and isoprene; Vinyl chloride, vinylidene chloride, bromide Vinyl halides such as vinyl and vinyl iodide; vinyl acetate and propion Vinyl esters such as vinyl and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylate-n-octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, methacryl Α-methylene fatty acid monocarboxylic acid esters such as dimethylaminoethyl acrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, acrylate-n-butyl, acrylate isobutyl, propyl acrylate, acrylate-n-octyl , Acrylic acid esters such as dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as ter and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N- such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone. Examples thereof include vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

  The polymerizable monomer droplets dispersed in the aqueous medium as described above are heated and stirred to cause suspension polymerization of the polymerizable monomer droplets. Usually, the polymerization treatment is performed at a temperature of 50 to 100 ° C. for 8 to 48 hours.

  In the polymerizable monomer, in order to form a crosslinked polymer, suspension polymerization may be performed in the presence of the following crosslinking agent. Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol acrylate, triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexaglycol dimethacrylate, neopentyl glycol dimethacrylate, Dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane tri Methacrylate, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, dibromoneopentyl glycol dimethac Rate, can be appropriately used a general crosslinking agent such as diallyl phthalate. These crosslinking agents are used in an amount of 0.05 to 10 parts, preferably 0.1 to 10 parts, based on 100 parts of the polymerizable monomer.

  In the present invention, a polymerization initiator may be added to the aqueous medium in which the droplets are dispersed. However, since the polymerization initiator is uniformly applied to the droplets of the individual polymerizable monomers, the polymerization property is increased. It is preferably contained in the monomer composition. Examples of such polymerization initiators include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbohydrate). Nitrile), 2,2'-azobis-4-methoxy-2,4-dimethylpareronitrile, other azobisisobutyronitrile (AIBN) or azo-based polymerization initiators; benzoyl peroxide, methyl ethyl ketone Examples thereof include peroxide polymerization initiators such as peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorolylbenzoyl peroxide, and lauroyl peroxide. Alternatively, suspension polymerization may be carried out in the presence of a material soluble in the polymerizable monomer in the polymerizable monomer.

  In addition, an organic solvent may be mixed with the polymerizable monomer. Examples of organic solvents include dichloromethane, dichloroethane, trichloromethane, trichloroethane, methyl acetate, ethyl acetate, propyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate, methyl propionate, ethyl propionate, diethyl ether, dipropyl Ether, benzene, toluene, xylene, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran and the like can be used, and they may be used alone or in combination.

  A dispersion of resin fine particles can be obtained by polymerizing the polymerizable monomer in the droplets as described above.

2. Toner chromatography method for producing a toner production method of the present invention is a method of producing by aggregating / fusion bonding the resin particles and at least colorant particles of the resulting dispersion by the above method.

  Aggregation is used with the concept that at least a plurality of resin fine particles are simply attached. Although the constituent particles are in contact with each other by aggregation, so-called hetero-aggregated particles (group) are formed in which no bonding due to melting of resin fine particles or the like is formed. A group of particles formed by such aggregation is referred to as aggregated particles.

  Fusion is used in a concept that is intended to form a bond as a unit of use and handling by forming a bond due to melting of resin fine particles or the like in at least a part of the interface of the individual constituent particles in the aggregated particles. . The particle group that has undergone such fusion is referred to as fused particles.

  Aggregation / fusion refers to an action in which aggregation and fusion occur simultaneously or stepwise, or an action that causes aggregation and fusion to occur simultaneously or stepwise.

  In the agglomeration / fusion, a resin fine particle dispersion and at least a separately prepared colorant dispersion are mixed, and the particles are agglomerated to form agglomerated particles (hereinafter, agglomeration step); A first method including a step of forming toner particles by fusing by heating (hereinafter referred to as a fusing step) may be employed, or the toner may be formed by fusing at the same time as the formation of aggregated particles proceeds. You may employ | adopt the 2nd method of forming particle | grains.

  Specifically, in the aggregation step of the first method, the resin fine particle dispersion, the colorant particle dispersion, and, if necessary, the offset inhibitor fine particle dispersion (wax fine particle dispersion) are mixed with each other, and the flocculant is not less than the critical aggregation concentration. Addition and aggregation of resin fine particles and the like to form aggregated particles. In the fusing step, fusing is performed by heating to a temperature equal to or higher than the glass transition temperature of the resin in the aggregated particles.

  Specifically, in the second method, a flocculant is added to a dispersion obtained by mixing the resin fine particle dispersion, the colorant particle dispersion, and, if necessary, the offset preventive fine particle dispersion with each other, and then the resin. Fusion is performed at the same time as agglomeration is advanced by heating above the glass transition point of the fine particles.

  As the aggregating agent, a compound having a polarity different from that of the resin fine particles, for example, a compound having a monovalent or higher charge such as an ionic surfactant, a nonionic surfactant or a metal salt can be used. Specifically, water-soluble surfactants such as the above-mentioned cationic surfactants, anionic surfactants and nonionic surfactants; acids such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid and oxalic acid; magnesium chloride, Metal salts of inorganic acids such as calcium chloride, sodium chloride, aluminum chloride, aluminum sulfate, calcium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate; sodium acetate, potassium formate, sodium oxalate, sodium phthalate, potassium salicylate, etc. Aliphatic acids and aromatic acid metal salts; metal salts of phenols such as sodium phenolate, metal salts of amino acids, triethanolamine hydrochloride, inorganic salts of aromatic amines such as aniline hydrochloride Is mentioned. When considering the stability of the aggregated particles, the stability of the aggregating agent with respect to heat and time, and the removal during washing, a metal salt of an inorganic acid is preferable in terms of performance and use.

  The amount of the flocculant to be added varies depending on the valence of the charge, but any of them may be small, and 3% by mass or less in the case of monovalent and 1% by mass or less in the case of divalent to the added dispersion. In the case of trivalent, it is about 0.5% by mass or less. A smaller amount of the flocculant is preferable, and a compound having a higher valence is preferable because the amount added can be reduced.

  As the colorant used in the present invention, various organic or inorganic pigments and dyes as shown below can be used.

  That is, examples of the black pigment include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Yellow pigments include yellow lead, zinc yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, Permanent Yellow NCG, Tartragin Lake and others.

  Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.

  Red pigments include Bengala, Pangdan, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red, Calcium Salt, Lake Red C, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B etc.

  Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.

  Examples of blue pigments include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue derivatives, first sky blue, and induslen blue BC.

  Examples of the green pigment include chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G, and phthalocyanine green.

  Examples of white pigments include zinc oxide, titanium oxide, zirconium oxide, aluminum oxide, calcium oxide, calcium carbonate, and tin oxide.

  Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, alumina white, and kaolin.

  Examples of the dye include rose bengal, triphenylmethane dye, monoazo dye, disazo dye, rhodamine dye, condensed azo dye, and phthalocyanine dye.

  The pigment is usually used in the form of a dispersion dispersed in water in the presence of the dispersion stabilizer. Preferably, the pigment is provided with a self-dispersibility by introducing a hydrophilic group such as a carboxylic acid group on the surface. Is used in the form of a dispersion obtained by self-dispersing in water. The pigment desirably has a dispersed particle diameter of 1 μm or less in the dispersion, and more preferably in the range of 30 to 300 nm.

  These colorants can be used alone or in combination. The colorant is used in an amount of 1 to 20 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the polymer contained in the toner. When the amount of the colorant is more than 20 parts by mass, the toner fixing property is lowered, and when the amount is less than 1 part by mass, a desired image density cannot be obtained.

  As the offset preventive agent, any of known waxes can be used. Specifically, olefinic waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymerized polyethylene, paraffin wax; behenic acid ester , Ester waxes having a long chain aliphatic group such as montanic acid ester and stearic acid ester; plant waxes such as hydrogenated castor oil and carnauba wax; ketones having a long chain alkyl group such as distearyl ketone; having an alkyl group Silicone; higher fatty acid such as stearic acid; (partial) ester of polyhydric alcohol such as long chain fatty alcohol, pentaerythritol, trimethylolpropane and long chain fatty acid; oleic acid amide, stearic acid amide, palmitic acid amide, etc. Examples include higher fatty acid amides It is.

  The offset inhibitor is preferably used in the form of a dispersion dispersed in water in the presence of the dispersion stabilizer. The offset inhibitor preferably has a dispersed particle size of 2 μm or less in the dispersion, and more preferably in the range of 50 to 500 nm. The offset inhibitor is usually used in an amount of 1 to 25 parts by mass, preferably 3 to 20 parts by mass, more preferably 5 to 15 parts by mass with respect to 100 parts by mass of the resin particles.

  As the charge control agent, there are various types of substances that can give positive or negative charge by triboelectric charging. As the positive charge control agent, for example, a two-glossin dye such as Nigrosine Base ES (manufactured by Orient Chemical Industries). , P-51 (manufactured by Orient Chemical Co., Ltd.), quaternary ammonium salts such as copy charge PX VP435 (manufactured by Clariant), alkoxylated amines, alkylamides, molybdate chelate pigments, and PLZ1001 (manufactured by Shikoku Kasei Kogyo Co., Ltd.) And imidazole compounds.

  As the negative charge control agent, for example, Bontron S-22 (manufactured by Orient Chemical Industries), Bontron S-34 (manufactured by Orient Chemical Industries), Bontron E-81 (manufactured by Orient Chemical Industries), Bontron E-84 ( (Orient Chemical Co., Ltd.), Spiron Black TRH (Hodogaya Chemical Co., Ltd.) and other metal complexes, Thioindio pigment, Bontron E-89 (Orient Chemical Industries Co., Ltd.), Calex Allen compounds, Copy Charge NX VP434 ( Quaternary ammonium salts such as Clariant), and fluorine compounds such as magnesium fluoride and carbon fluoride. In addition to the above-mentioned metal complexes serving as negative charge control agents, oxycarboxylic acid metal complexes, dicarboxylic acid metal complexes, amino acid metal complexes, diketone acid metal complexes, diamine metal complexes, azo group-containing benzene- It may have various structures such as a benzene derivative skeleton metal complex and an azo group-containing benzene-naphthalene derivative skeleton metal complex.

  These charge control agents desirably have a particle size of about 10 to 100 nm from the viewpoint of obtaining uniform dispersion. When the particle diameter exceeds the upper limit of the above range in the form supplied as a commercial product, it is desirable to adjust to an appropriate particle diameter by a known method such as pulverization with a jet mill or the like.

  The particle shape (for example, circularity) of toner particles obtained by aggregation / melting can be easily controlled by adjusting the heating conditions in the aging process of the fusing process.

  The toner particles obtained by agglomeration / melting in the dispersion are subjected to washing treatment, dried, and then subjected to external addition treatment as necessary to obtain toner.

  In the washing treatment, acidic water or basic water in some cases is added to the toner particles in an amount several times that of the toner particles, followed by stirring and solid-liquid separation to obtain a toner cake. Pure water is added several times to the toner cake and stirred, followed by solid-liquid separation. This operation is repeated several times, and when the pH of the filtrate after solid-liquid separation reaches about 7, the toner particles are obtained.

  In the drying process, the toner particles obtained in the cleaning process are dried at a temperature not higher than the glass transition temperature. At this time, it is preferable to circulate dry air according to the required temperature, or to heat under vacuum conditions. In the drying step, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be adopted.

  In the external addition treatment step, single or plural kinds of external additives are added and mixed to the toner particles subjected to the drying treatment. External additives include fine powder silica, alumina, titania and other fluidity improvers, magnetite, ferrite, cerium oxide, strontium titanate, conductive titania and other inorganic fine particles, styrene resin, acrylic resin, etc. , Lubricants etc. are used. The amount of these external additives used may be appropriately selected depending on the desired performance, and is usually 0.05 to 10 parts by mass with respect to 100 parts by mass of the toner particles. These additives may be contained inside the toner particles.

  Next, the developer will be described.

The toner produced by the toner production method of the present invention can be used as a non-magnetic one-component developer or a two-component developer.

  When used as a two-component developer by mixing with a carrier, the carrier may be a conventionally known material such as a metal such as iron, ferrite or magnetite, or an alloy of such a metal with a metal such as aluminum or lead. Among these, ferrite is preferable. The volume average particle diameter of the carrier is preferably 15 to 100 μm, and more preferably 25 to 80 μm.

  The volume average particle diameter of the carrier can be measured by a laser diffraction type particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are coated with a resin, or a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. As the coating resin, known resins can be used, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, and fluorine-containing polymer resins. In addition, as the resin for constituting the resin-dispersed carrier, known resins can be used, and examples thereof include styrene-acrylic resins, polyester resins, fluorine resins, phenol resins, and the like.

  Next, the image forming apparatus and the process cartridge will be described.

  FIG. 1 is a cross-sectional view showing an example of an image forming apparatus used in the present invention.

  In FIG. 1, reference numeral 50 denotes a photosensitive drum (photosensitive member) which is an image bearing member, and is a photosensitive member in which an organic photosensitive layer is coated on a drum and a resin layer is coated thereon. It is rotated. Reference numeral 52 denotes a scorotron charger (charging means) for uniformly charging the circumferential surface of the photosensitive drum 50 by corona discharge. Prior to the charging by the charger 52, the peripheral surface of the photosensitive member may be discharged by performing exposure by the pre-charging exposure unit 51 using a light emitting diode or the like in order to eliminate the history of the photosensitive member in the previous image formation.

  After uniform charging of the photoreceptor, image exposure based on the image signal is performed by an image exposure unit 53 as an image exposure unit. The image exposure unit 53 in this figure uses a laser diode (not shown) as an exposure light source. Scanning on the photosensitive drum is performed by the light whose optical path is bent by the reflection mirror 532 through the rotating polygon mirror 531 and the fθ lens, and an electrostatic latent image is formed.

Here, the charger 52 and the reverse development process employing at images forming method, a photosensitive member surface is uniformly charged, a region where image exposure is performed, i.e., the photoreceptor of the exposed portion potential (exposed area) Is an image forming method in which the image is visualized by a developing step (means). On the other hand, the unexposed portion potential is not developed by the developing bias potential applied to the developing sleeve 541.

The electrostatic latent image is then developed by a developing device 54 as developing means. A developing device 54 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 50, and development is performed by a developing sleeve 541 that contains a magnet and rotates while holding the developer. The inside of the developing device 54 is composed of developer agitating / conveying members 544 and 543, a conveying amount regulating member 542, and the like, and the developer is agitated and conveyed and supplied to the developing sleeve. Controlled by members. The amount of the developer transported varies depending on the linear velocity of the applied organic electrophotographic photosensitive member and the specific gravity of the developer, but is generally in the range of ^{20 to} 200 mg / cm ² .

  The developer is transported to the development zone with the layer thickness regulated by the transport amount regulating member, and development is performed. At this time, usually, development is performed by applying a DC bias between the photosensitive drum 50 and the developing sleeve 541 and, if necessary, an AC bias voltage. Further, the developer is developed in contact with or not in contact with the photoreceptor. The potential of the photosensitive member is measured by providing a potential sensor 547 above the development position as shown in FIG.

  The recording paper P is fed to the transfer area by the rotation operation of the paper feed roller 57 when the transfer timing is ready after the image formation.

  In the transfer area, a transfer electrode (transfer means: transfer device) 58 on the peripheral surface of the photosensitive drum 50 is operated in synchronization with the transfer timing, and the fed recording paper P is sandwiched and transferred.

  Next, the recording paper P is neutralized by a separation electrode (separator) 59 that is activated almost simultaneously with the transfer electrode, separated by the peripheral surface of the photosensitive drum 50, and conveyed to the fixing device 60. After the toner is welded by heating and pressurizing the pressure roller 602, the toner is discharged to the outside of the apparatus via the paper discharge roller 61. The transfer electrode 58 and the separation electrode 59 are retracted away from the peripheral surface of the photosensitive drum 50 after the recording paper P has passed to prepare for the next toner image formation. In FIG. 1, a transfer band electrode of corotron is used as the transfer electrode 58. The transfer electrode setting conditions differ depending on the process speed (peripheral speed) of the photosensitive member and cannot be specified. For example, the transfer current is set to +100 to +400 μA, and the transfer voltage is set to +500 to +2000 V. can do.

  On the other hand, after the recording paper P is separated, the photosensitive drum 50 removes and cleans residual toner by pressure contact of the blade 621 of the cleaning device (cleaning means) 62, and again performs charge removal by the pre-charge exposure unit 51 and charging by the charger 52. Then, the next image forming process is started.

  Reference numeral 70 denotes a detachable process cartridge in which a photoconductor, a charger, a transfer device, a separator, and a cleaning device are integrated.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.

Example 1
<Preparation of resin fine particle dispersion>
A resin solution was prepared by dissolving 10 parts by mass of a polyester resin (Mw: 5000, Mw / Mn: 2.4, acid value: 70, softening temperature: 100 ° C., Tg: 50 ° C.) in 400 parts by mass of toluene.

  The aqueous medium was prepared by adding polyvinyl alcohol and sodium dodecylbenzenesulfonate as a dispersion stabilizer to water. In addition, 1 mass% of polyvinyl alcohol and 0.5 mass% of sodium dodecylbenzenesulfonate were added with respect to the total mass of the aqueous medium.

  The resin solution was discharged from a nozzle of a discharge device (nozzle shape: circular, nozzle diameter: 2 μm) into an aqueous medium in which the resin solution was gently stirred to prepare a dispersion having resin solution droplets. Thereafter, this dispersion was heated to 70 ° C. for 8 hours to remove toluene, and a resin fine particle dispersion having a resin concentration of about 6% by mass was prepared. The volume average particle size of the resin fine particles was 500 nm as measured using “Microtrac UPA-150” (manufactured by Nikkiso).

  100 kg of the resin solution was continuously discharged from the nozzle of the discharge device, but no clogging of the nozzle was observed, and the resin fine particle dispersion could be stably prepared.

<Preparation of wax fine particle dispersion>
680 g of distilled water, 180 g of carnauba wax (manufactured by Noda Wax Co., Ltd.), 17 g of sodium dodecylbenzenesulfonate “Neogen SC” (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are mixed, Dispersion was performed to prepare a wax fine particle dispersion. The volume average particle size of the wax fine particles was 110 nm as measured using a dynamic light scattering particle size distribution analyzer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

<Preparation of colorant fine particle dispersion>
A self-dispersing pigment having a carboxylic acid group introduced on the surface of carbon black was dispersed in distilled water to prepare a colorant fine particle dispersion having a solid content of 17% by mass. The volume average particle diameter of the dispersed carbon black was 103 nm as measured using a dynamic light scattering particle size distribution analyzer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

<Production of toner particles>
The reactor is charged with 500 g of the resin fine particle dispersion, 6.8 g of the wax fine particle dispersion, and 12 g of the colorant fine particle dispersion, and a 2N aqueous sodium hydroxide solution is added with stirring to adjust the pH of the solution to 10.0. did. Next, after adding 10 g of 50 mass% magnesium chloride aqueous solution to this solution, it heated up at 65 degreeC, stirring, and stirring was continued until it grew to the desired average particle diameter. When the desired particle size was reached, 60 g of 20% by mass sodium chloride aqueous solution was added, the temperature was raised to 80 ° C., and stirring was continued at 80 ° C. until the circularity reached about 0.96. When the desired circularity is reached, the solution is cooled to room temperature, and the solid content is separated from the solution by solid-liquid separation. The obtained solid content is washed with distilled water several times, and then dried to dry the toner particles. Obtained.

  The obtained toner particles have a volume average particle size of 5.3 μm (measured with “Coulter Counter TAII type”), and the ratio of volume average particle size to number average particle size (Dv / Dp) is 1.16 (calculated from the measured value). The average circularity was 0.96 (measured with “FPIA-2000”).

<Toner particle external treatment>
To 100 parts of the above toner particles, 0.5 part of silica “H-2000” (manufactured by Wacker) is added, and using a “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.), the mixture is mixed for 1 minute at 1000 rpm and externally added And “Toner 1” was produced.

Example 2
<Production of toner>
“Toner” was used in the same manner as in Example 1 except that a polyester resin (Mw: 6200, Mw / Mn: 2.0, acid value: 12, softening temperature: 120 ° C., Tg: 64 ° C.) was used as the resin material. 2 "was produced. The volume average particle diameter of the resin fine particles of Example 2 is 600 nm, the volume average particle diameter of the toner particles is 5.4 μm, the ratio of the volume average particle diameter to the number average particle diameter is 1.19, and the average circularity is 0.00. 96.

Example 3
<Preparation of resin fine particles>
A polymerizable monomer solution was prepared by adding and dissolving 2 parts of azobisisobutylnitrile to 70 parts of styrene, 15 parts of butyl acrylate, and 15 parts of methacrylic acid.

  The aqueous medium was prepared by adding polyvinyl alcohol and sodium dodecylbenzenesulfonate as a dispersion stabilizer to water. In addition, 1 mass% of polyvinyl alcohol and 0.5 mass% of sodium dodecylbenzenesulfonate were added with respect to the total mass of the aqueous medium.

  Dispersion liquid having droplets of polymerizable monomer solution discharged from a nozzle (nozzle shape: circular, nozzle diameter: 2 μm) of a discharge device into an aqueous medium in which the polymerizable monomer solution is gently stirred Was made.

  Thereafter, this dispersion was polymerized for 5 hours in a state heated to 70 ° C., and after completion of the polymerization, cooled to room temperature to prepare a resin fine particle dispersion having a resin concentration of about 6% by mass. The volume average particle diameter of the resin fine particles was 650 nm.

<Production of toner>
“Toner 3” was produced in the same manner as in Example 1 except that the resin fine particles were used as the resin fine particle dispersion. The volume average particle diameter of the toner particles was 5.4 μm, the ratio of the volume average particle diameter to the number average particle diameter (Dv / Dp) was 1.21, and the average circularity was 0.96.

Comparative Example 1
<Preparation of resin fine particle dispersion>
A resin solution was prepared by dissolving 10 parts by mass of a polyester resin (Mw: 5000, Mw / Mn: 2.4, acid value: 70, softening temperature: 100 ° C., Tg: 50 ° C.) in 400 parts by mass of toluene.

  The aqueous medium was prepared by adding polyvinyl alcohol and sodium dodecylbenzenesulfonate as a dispersion stabilizer to water. In addition, 1 mass% of polyvinyl alcohol and 0.5 mass% of sodium dodecylbenzenesulfonate were added with respect to the total mass of the aqueous medium.

The resin solution was added to the aqueous medium, and the resin solution was dispersed in the aqueous medium using a high-speed stirrer to prepare a resin fine particle dispersion having droplets of the resin solution. Thereafter, this dispersion was stirred at 70 ° C. for 8 hours to remove toluene, and a dispersion of resin fine particles having a resin concentration of about 6% by mass was prepared. The volume average particle diameter of the resin fine particles was 6 nm.

<Production of toner>
“Toner 4” was prepared in the same manner as in Example 1 except that the resin fine particles were used as the resin fine particle dispersion. The volume average particle diameter of the toner particles was 5.4 μm, the ratio of the volume average particle diameter to the number average particle diameter (Dv / Dp) was 1.45 , and the average circularity was 0.82 .

Comparative Example 2
<Preparation of colorant-containing resin fine particle dispersion>
Self-dispersing pigment 5 in which 10 parts by mass of a polyester resin (Mw: 5000, Mw / Mn: 2.4, acid value: 70, softening temperature: 100 ° C., Tg: 50 ° C.), and a carboxylic acid group is introduced on the surface of carbon black .6 parts by mass was dissolved and dispersed in 400 parts by mass of toluene using a stirrer to prepare a colorant-containing resin solution.

  The aqueous medium was prepared by adding polyvinyl alcohol and sodium dodecylbenzenesulfonate as a dispersion stabilizer to water. In addition, 1 mass% of polyvinyl alcohol and 0.5 mass% of sodium dodecylbenzenesulfonate were added with respect to the total mass of the aqueous medium.

  The colorant-containing resin solution was discharged from a nozzle (nozzle shape: circular, nozzle diameter: 2 μm) of a discharge device into an aqueous medium in which the colorant-containing resin solution was gently stirred to prepare a dispersion having droplets of the resin solution. Thereafter, this dispersion was heated to 70 ° C. for 8 hours to remove toluene, and a resin fine particle dispersion having a resin concentration of about 6% by mass was prepared. The volume average particle size of the resin fine particles was 570 nm.

  When 10 kg of the colorant-containing resin solution was discharged from the nozzle of the discharge device, the nozzle was clogged, and production could not be continued.

Table 1 shows the average particle diameter and Dv / Dp of the produced resin fine particles, the volume average particle diameter of the toner particles, Dv / Dp, and the average circularity.

<Preparation of developer>
The above “toners 1 to 4” were mixed with a silicone resin coated carrier to prepare a two-component developer having a toner concentration of 6% by mass. The developers corresponding to the toners are referred to as “Developers 1 to 4”.

<Evaluation>
As an evaluation machine, a digital printer “Sitios 7075” (manufactured by Konica Minolta) was used.

  An image for evaluation was created by printing an original image in which a character image having a pixel ratio of 7%, a human face photo, a solid white image, and a solid black image are divided into ¼ equal parts on A4 size recording paper.

  The printing was performed continuously for 200,000 sheets in an environment of high temperature and high humidity (30 ° C., 80% RH), and the image density, fog and resolution of the obtained print were evaluated. However, before starting printing, setting powder was applied to the surface of the photosensitive member, and the photosensitive member and the cleaning blade were blended to perform printing.

(Image density)
The density of the solid black image portion at the initial printing and after printing 200,000 sheets was measured with a reflection densitometer “RD-918” (manufactured by Macbeth). The image density is the relative reflection density when the reflection density of the recording paper is “0”.

Evaluation criteria A: Good at an image density of 1.2 or more both at the initial printing and after printing 200,000 sheets. ○: An image density of 1.0 or higher at both the initial printing and after printing 200,000 sheets. At least one of the initial printing and after printing 200,000 sheets is a practically problematic level when the image density is less than 1.0.

(Fog)
The image density of the unprinted portion after the initial printing and after 200,000 printing was measured with a reflection densitometer “RD-918” (manufactured by Macbeth). The reflection density of recording paper (white paper) is measured at 20 locations at the absolute image density, and the average value is defined as the white paper density. Next, the white area of the recording paper on which the image was formed was similarly measured at 20 locations at the absolute image density, and the value obtained by subtracting the white paper density from the average density was evaluated as the fog density.

Evaluation Criteria A: Good at a fog density of 0.005 or less both in the initial stage of printing and after 200,000 prints ○: A level where there is no practical problem at a fog density of 0.01 or less both in the initial stage of printing and after 200,000 prints X: Initial stage At least one after 200,000 prints has a fog density of more than 0.01, which is a practical problem.

(resolution)
The resolution of the character image at the initial printing and after printing 200,000 sheets was visually evaluated.

Evaluation criteria ◎: Good with no difference in resolution after printing 200,000 sheets at the initial stage of printing ○: Level with a slight decrease in resolution after printing 200,000 with halftone images, but no problem in practical use ×: After printing 200,000 sheets There is a significant decrease in resolution and there are practical problems. Table 2 shows the evaluation results.

  As is apparent from Table 2, the image printed using the examples “Toners 1 to 3” of the present invention was compared with the image printed using the comparative example “Toner 4”, and the characteristics of image density, fog, and resolution were compared. It turns out that is excellent.

It is sectional drawing which shows an example of the image forming apparatus used by this invention.

Explanation of symbols

50 Photosensitive drum (photosensitive member)
51 Pre-charging exposure section 52 Scorotron charger (charging means)
53 Image exposure device 57 Paper feed roller 58 Transfer electrode 59 Separating electrode 60 Fixing device 61 Paper discharge roller 62 Cleaning device 70 Process cartridge P Recording paper

Claims (2)

A droplet of a resin solution in which a resin is dissolved in a solvent , the nozzle shape is substantially circular, the nozzle diameter is 100 nm to 5 μm , and the pulsation is caused by the action of pressure, electric force, magnetic force, gas, or bubble generation. a nozzle head that utilizes, in an aqueous medium which is stirred in the strong enough to not break the droplet, ejected by the step of producing a dispersion having droplets of the resin solution, the dispersion process and method for producing a toner for developing electrostatic images, which comprises manufactured through a step of at least aggregating / fusion bonding the colorant particles and the resin particles solvent is removed to prepare a resin particle from. The droplets of the polymerizable monomer, a substantially circular nozzle shape, a nozzle diameter of 100 nm to, utilize pressure, electrical forces, magnetic forces, the pulsation caused by the action of either the generation of gas or bubbles a nozzle head, generating the droplets in a solution which does not dissolve the polymerizable monomer are stirred in the strong enough to not break, discharge, the dispersion with droplets of the polymerizable monomer a step of the step of preparing a resin fine particles by polymerizing said droplets, for developing an electrostatic image, characterized by manufactured through a step of at least aggregating / fusion bonding the colorant particles and the fine resin particles Toner manufacturing method.

Images