JP2002278150A - Manufacturing method for toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently manufacturing toner which has less coarse particles or fine particulates not through a classifying process and generates neither print white stripes nor fogging. SOLUTION: Colored polymer particle water dispersion liquid is carried to a vaporization tank by using a centrifugal pump, the dispersion liquid is extracted from the bottom part of the vaporization tank by the centrifugal pump and carried to a heat exchanger, and the dispersion liquid is flushed from the top part of the vaporization tank, and the water dispersion liquid is carried to a washing tank by the centrifugal pump and acid washing, water washing, and further dehydration and drying are carried out to remove soluble components from the polymer particles, thereby obtaining toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner for developing an electrostatic latent image formed by an electrophotographic method, an electrostatic recording method or the like, and more particularly, to a method for producing a toner without a classification step. The present invention relates to a method for efficiently producing a toner having few particles or fine particles and free from white streaks and fogging.

[0002]

2. Description of the Related Art As a method for producing a toner, (1) a pulverization method of kneading, pulverizing and classifying a binder resin with a colorant, a charge controlling agent, a release agent, etc. to obtain colored particles; The dimer,
Or a polymerizable monomer, a charge control agent, a mixture of a release agent,
A method called a polymerization method or an aggregation method in which suspension polymerization, emulsion polymerization or dispersion polymerization is performed, and aggregation is performed as necessary to obtain colored particles having a desired particle size. (3) A resin containing a colorant is dissolved in an organic solvent. Then, there is a dissolution dispersion method obtained by inverting the solvent to an aqueous medium. In the case of obtaining a toner by a polymerization method, an aggregation method or a solution dispersion method, the prepared colored polymer particle dispersion liquid is washed to remove unnecessary components, and dehydrated,
Must dry. The surroundings of the colored polymer particles in the dispersion are usually protected by a dispersion stabilizer so that the particles are stably dispersed in an aqueous medium. In the dispersion washing step, the dispersion stabilizer, volatile components, and the like are removed by raising the temperature of the dispersion, blowing steam, or changing the pH by adding an acid or alkali. When the dispersion stabilizer or the like is removed, the stability of the colored polymer particles in an aqueous system becomes low. The dispersion is transferred from the polymerization reaction tank to a flocculation tank, a demonomerization tank, an acid washing tank, a water washing tank, a dehydrator, or the like. A positive displacement pump such as a diaphragm pump which has been awarded for transferring an aqueous dispersion of polymer particles has conventionally been used for transferring toner particles (= colored polymer particles). However, at the time of this transfer, the colored polymer particles agglomerate, causing clogging of the pipes, which may hinder production.
In addition, coarse aggregated particles may be mixed in the toner product, which may cause white streaks or fog.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method capable of efficiently producing a toner which has few coarse or fine particles and does not cause white streaks or fog. The present inventor studied the washing step in detail, and as a result, transported the colored polymer particle dispersion using a turbo-type pump to remove volatile components such as unreacted monomers or water-soluble components such as a dispersion stabilizer. The removal of coarse particles and fine particles is reduced,
It has been found that image quality defects such as fogging are eliminated, and the present invention has been completed based on such knowledge.

[0004]

Thus, according to the present invention, there is provided a process for preparing an aqueous dispersion of colored polymer particles, and transferring the aqueous dispersion of colored polymer particles using a turbo-type pump. There is provided a method for producing a toner including a step of removing a volatile component and / or a water-soluble component from particles.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the toner production method of the present invention, a step of preparing an aqueous dispersion of colored polymer particles, transferring the aqueous dispersion of colored polymer particles using a turbo-type pump, and And a step of removing volatile components and / or water-soluble components from water.

The turbo type pump used in the present invention is industrially used, and specifically includes a centrifugal pump, a mixed flow pump and an axial flow pump. A centrifugal pump is one in which the flow discharged from the impeller is mainly in a plane perpendicular to the main shaft, and a centrifugal pump having a spiral casing directly on the discharge side of the impeller is called a spiral pump, and a guide vane type diffuser is used. The one equipped is called a diffuser pump. The mixed-flow pump is a type in which the flow discharged from the impeller is in a conical surface about the centerline of the main shaft, and is usually provided with a guide vane-shaped diffuser, especially a device provided with a spiral casing. It is called a pump. In addition, the axial flow pump is one in which the flow discharged from the impeller is in a cylindrical surface concentric with the main shaft, and usually includes a guide vane-shaped diffuser. Among these turbo-type pumps, in the present invention, a centrifugal pump is preferable. In particular, as shown in FIG. 1, a so-called open type impeller without an impeller side plate, and one of two sealing surfaces having a knife-edge shape A centrifugal pump provided with a linear contact type mechanical seal is preferred.

A preferred centrifugal pump used in the present invention will be described in detail with reference to the drawings. 1 is a sectional view of a centrifugal pump, FIG. 2 is an enlarged view of a mechanical seal portion 4, and FIG. 3 is a view showing a shape of an impeller. The centrifugal pump shown in FIG. 1 includes a casing 1, an impeller 3, a main shaft 9 of the impeller, and a mechanical seal portion 4. Aqueous dispersion is inlet 2
And is pushed out in a plane perpendicular to the main axis by the rotation of the impeller, collected along the spiral casing, and discharged from the discharge port 502. Impeller 3
Has a smooth curved shape as shown in FIG.
The tip of the wing extends around the suction port and extends,
A strong impact is not applied to the dispersion. Further, the impeller is not provided with a side plate in order to prevent clogging in a gap between the impeller and the casing. The mechanical seal portion 4 includes a stationary ring 14 and a rotating ring 15 so that the dispersion liquid does not leak axially due to contact between the two rings. The stationary ring side is flat, the rotating ring side has a knife edge shape, and is in line contact with the stationary ring side. In a mechanical seal by line contact, when a film of polymer particles is formed on the sealing surface, the film is peeled off in a thread shape by a knife edge on the rotating ring side, and the thread film can be washed out with seal water.

The aqueous dispersion of colored polymer particles used in the present invention is prepared by a polymerization method, an aggregation method, a dissolution dispersion method, or the like. As a specific example of the preparation of the aqueous dispersion of colored polymer particles, a monomer composition containing an additive such as a polymerizable monomer and a colorant is subjected to suspension polymerization, emulsion polymerization or dispersion polymerization in an aqueous medium. A method of agglomerating if necessary; a method of subjecting the polymer particles, monomers and additives to suspension polymerization, emulsion polymerization or dispersion polymerization in an aqueous medium, and aggregating as necessary;
A method of coagulating polymer particles and additives such as a colorant in an aqueous medium; dissolving a resin containing a colorant in an organic solvent;
Next, a method of inverting the phase of the solvent to an aqueous medium and the like can be mentioned.

The colored polymer particles usually contain a binder resin and a colorant as essential components, and further contain other additives such as a charge control agent and a release agent as required.
The binder resin that constitutes the colored polymer particles may be any resin that is commonly used as a binder resin for toner. For example, an alkyl (meth) acrylate polymer, styrene-
Alkyl (meth) acrylate copolymer, styrene polymer, styrene-acrylonitrile copolymer, styrene
Examples include butadiene copolymer, styrene-maleic anhydride copolymer, polyethylene, polypropylene, polyester, norbornene-based resin, polyurethane, epoxy resin, silicone resin, polyamide and the like.

As the colorant, dyes and pigments generally known as colorants for toner can be used. Examples of the black colorant include carbon black, nigrosine-based dyes and pigments; magnetic particles such as cobalt, nickel, iron tetroxide, iron manganese oxide, iron zinc oxide, and nickel iron oxide; When using carbon black,
It is preferable to use a toner having a primary particle size of 20 to 40 nm because good image quality can be obtained and the safety of the toner to the environment is enhanced. Colorants for the color toner include a yellow colorant, a magenta colorant, and a cyan colorant. Compounds such as azo pigments and condensed polycyclic pigments are used as the yellow colorant. Specifically, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65,
73, 83, 90, 93, 97, 120, 138, 15
5, 180, and 181. As the magenta colorant, compounds such as azo pigments and condensed polycyclic pigments are used. Specifically, C.I. I. Pigment Red 48,
57, 58, 60, 63, 64, 68, 81, 83, 8
7, 88, 89, 90, 112, 114, 122, 12
3, 144, 146, 149, 163, 170, 18
4, 185, 187, 202, 206, 207, 20
9, 251, C.I. I. Pigment Violet 19, and the like. As the cyan coloring agent, a copper phthalocyanine compound and its derivative, an anthraquinone compound and the like can be used. Specifically, C.I. I. Pigment Blue 2,
3, 6, 15, 15: 1, 15: 2, 15: 3, 15:
4, 16, 17, and 60. These colorants are usually 0.1 to 100 parts by weight of the binder resin.
It is used in a proportion of 50 parts by weight, preferably 1 to 20 parts by weight.

As the charge control agent, various positively or negatively chargeable charge control agents can be used. For example, metal complexes of organic compounds having a carboxyl group or a nitrogen-containing group, metal-containing dyes, nigrosine and the like can be mentioned.
More specifically, Spiron Black TRH (Hodogaya Chemical Co., Ltd.), T-77 (Hodogaya Chemical Co., Ltd.), Bontron S-34 (Orient Chemical Co., Ltd.) Bontron E-84
(Orient Chemical Co., Ltd.), Bontron N-01 (Orient Chemical Co., Ltd.), Copy Blue-PR (Clariant Co., Ltd.), etc. and / or a quaternary ammonium (salt) group-containing copolymer, sulfonic acid ( A charge control resin such as a salt) group-containing copolymer can be used. The charge control agent is generally used in an amount of 0.01 to 100 parts by weight of the binder resin.
It is preferable to use 10 to 10 parts by weight, particularly 0.03 to 8 parts by weight.

Examples of the release agent include low-molecular-weight polyolefin waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, and low-molecular-weight polybutylene; low-molecular-weight oxidized polypropylene, low-molecular-weight terminal-modified polypropylene in which the molecular terminals are substituted with epoxy groups. And terminal-modified polyolefin waxes such as block polymers of low-molecular-weight polyethylene and low-molecular-weight oxidized polyethylene, low-molecular-weight polyethylene having molecular ends substituted with epoxy groups, and block polymers of these and low-molecular-weight polypropylene; candelilla, carnauba, rice ,
Plant-based natural waxes such as wood wax and jojoba; petroleum-based waxes such as paraffin, microcrystalline and petrolactam and modified waxes thereof; mineral-based waxes such as montan, ceresin and ozokerite; synthetic waxes such as Fischer-Tropsch wax; pentaerythritol tetra Multifunctional such as pentaerythritol esters such as myristate, pentaerythritol tetrapalmitate and pentaerythritol tetralaurate and dipentaerythritol esters such as dipentaerythritol hexamyristate, dipentaerythritol hexapalmitate and dipentaerythritol hexalaurate One type or two or more types are exemplified.

Of these, synthetic waxes, end-modified polyolefin waxes, petroleum waxes and their modified waxes, and polyfunctional ester compounds are preferred. Among the polyfunctional ester compounds, in the DSC curve measured by the differential scanning calorimeter, the endothermic peak temperature at the time of temperature rise is in the range of 30 to 200 ° C, preferably 50 to 180 ° C, particularly preferably 60 to 160 ° C. Polyfunctional ester compounds such as pentaerythritol ester and dipentaerythritol ester having the same endothermic peak temperature in the range of 50 to 80 ° C. are particularly preferred from the viewpoint of the balance between fixing and peeling properties as a toner. Particularly, a dipentaerythritol ester having a molecular weight of 1,000 or more, dissolving at least 5 parts by weight at 25 ° C. with respect to 100 parts by weight of styrene, and having an acid value of 10 mg / KOH or less, has a remarkable effect on lowering the fixing temperature. Endothermic peak temperature is a value measured by ASTM D3418-82. The release agent is a binder resin 10
0.1 to 30 parts by weight, especially 1 to 0 parts by weight,
It is preferable to use 20 parts by weight.

The aqueous medium for dispersing the colored polymer particles used in the present invention preferably contains a dispersion stabilizer in order to maintain the dispersion stability of the particles. Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; aluminum hydroxide And metal hydroxides such as magnesium hydroxide and ferric hydroxide; water-soluble polymers such as polyvinyl alcohol, methylcellulose and gelatin; anionic surfactants, nonionic surfactants and amphoteric surfactants. Can be. Among these, dispersion stabilizers containing metal compounds, especially colloids of poorly water-soluble metal hydroxides, are preferred because they can narrow the particle size distribution of polymer particles and improve the sharpness of images. is there. In particular, when the crosslinkable monomer is not copolymerized, the dispersant containing the colloid of the poorly water-soluble metal hydroxide can improve the dispersion stability of the polymer particles during the polymerization, and the fixability and storage stability of the toner. It is suitable for improving. The dispersion stabilizer containing a colloid of a poorly water-soluble metal hydroxide is not limited by its manufacturing method, but the poorly water-soluble metal obtained by adjusting the pH of an aqueous solution of a water-soluble polyvalent metal compound to 7 or more is used. It is preferable to use a colloid of a hydroxide, particularly a colloid of a poorly water-soluble metal hydroxide formed by a reaction of a water-soluble polyvalent metal compound with an alkali metal hydroxide in an aqueous phase. The dispersion stabilizer is usually 0.1 to 20 parts by weight, based on 100 parts by weight of the binder resin,
Preferably, it is used in a ratio of 0.3 to 10 parts by weight. If this ratio is small, it is difficult to obtain sufficient polymerization stability, and aggregates are easily formed. Conversely, if this ratio is large, the toner particle size becomes too fine, which is not preferable.

The aqueous dispersion medium preferably contains a water-soluble organic compound or inorganic compound, particularly a water-soluble oxoacid salt, in addition to the dispersion stabilizer. Examples of the water-soluble oxo acid salts include borates, phosphates, sulfates, carbonates, silicates, nitrates and the like, preferably silicates, borates or phosphates, and particularly preferably. Borates. Sodium tetraborate, potassium tetrahydroborate; sodium tetraborate, sodium tetraborate decahydrate, sodium metaborate, sodium metaborate tetrahydrate, sodium peroxoborate tetrahydrate , Potassium metaborate, potassium tetraborate octahydrate and the like. As phosphates,
Sodium phosphinate monohydrate, sodium phosphonate pentahydrate, sodium hydrogen phosphonate pentahydrate,
Sodium phosphate dodecahydrate, disodium hydrogen phosphate, disodium hydrogen phosphate dodecahydrate, sodium dihydrogen phosphate monohydrate, sodium dihydrogen phosphate dihydrate, sodium hexametaphosphate, Sodium hypophosphate decahydrate, sodium diphosphate decahydrate, disodium dihydrogen diphosphate, disodium dihydrogen diphosphate hexahydrate, sodium triphosphate, cyclo-sodium tetraphosphate, Examples include potassium phosphinate, potassium phosphonate, potassium hydrogen phosphonate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, potassium diphosphate trihydrate, and potassium metaphosphate. Examples of the silicate include sodium metasilicate, sodium metasilicate nonahydrate, water glass, sodium orthosilicate and the like. The amount of the water-soluble oxo acid salt is determined by the amount of the dispersion stabilizer 1
It is usually 0.1 to 1000 parts by weight, preferably 1 to 100 parts by weight, based on 00 parts by weight. The water-soluble oxo acid salt is dissolved and contained in the aqueous dispersion medium.

Further, the aqueous dispersion of colored polymer particles may contain residues such as a polymerization initiator and a molecular weight regulator used for forming the polymer particles. Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid);
2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis-2-methyl-N-1,1′-
Bis (hydroxymethyl) -2-hydroxyethylpropionamide, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (1 -Cyclohexanecarbonitrile) and the like; methyl ethyl peroxide,
Di-t-butyl peroxide, acetyl peroxide,
Dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy neodecanoate, t-butyl peroxy pivalate, di-isopropyl peroxydioxide Peroxides such as carbonate and di-t-butylperoxyisophthalate can be exemplified. Further, a redox initiator obtained by combining these polymerization initiators and a reducing agent can be exemplified.

Examples of the molecular weight regulator include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide; Can be.

The colored polymer particles may be particles having a single-layer structure, or particles having a multilayer structure, which is so-called capsule type or core-shell type, which is soft inside and hard outside. Various functions can be imparted to the multilayer structure particles, for example, by lowering the fixing temperature,
It is possible to achieve both conflicting characteristics such as increasing the storable temperature.

The solid content of the aqueous dispersion of colored polymer particles is not particularly limited, but is usually 5 to 50% by weight, preferably 5 to 50% by weight.
４０40% by weight. Within this range, aggregation of the polymer particles is unlikely to occur.

In the production method of the present invention, the aqueous dispersion is transferred by the turbo pump to remove volatile components or water-soluble components from the aqueous dispersion of colored polymer particles. The transfer of the aqueous dispersion by the turbo-type pump includes transfer of the aqueous dispersion of the colored polymer particles to a step for removing the volatile component or the water-soluble component; removal of the volatile component or the water-soluble component. For transferring the aqueous dispersion of colored polymer particles from the step for transferring to the next step; transfer for circulating the aqueous dispersion of colored polymer particles in the step for removing volatile components or water-soluble components; etc. Is mentioned. In particular,
A tank for removing volatile or water-soluble components (hereinafter referred to as
To remove the aqueous dispersion of colored polymer particles into the removal tank, to remove the aqueous dispersion of colored polymer particles from the removal tank, and to heat the mixture externally to return to the original removal tank, or to remove the aqueous dispersion of colored polymer particles from the removal tank and to perform a dehydration step. The above-mentioned turbo type pump is used for transfer to the water. In the step of removing the volatile component, the aqueous dispersion becomes high temperature and aggregation of the polymer particles easily occurs. Therefore, the aqueous dispersion of the colored polymer particles is circulated in the step for removing the volatile component or the water-soluble component. It is preferable to use a turbo type pump in the transfer for performing the above. The transfer speed is appropriately selected according to the throughput in each step.

The volatile components include unreacted monomers, organic solvents, catalyst residues, and the like. By removing these, the charge amount is stabilized and the image quality is improved. The method for removing the volatile component is not particularly limited. For example, a method in which water is added to water while blowing a gas such as steam or nitrogen into a water dispersion of the colored polymer particles under reduced pressure, or water is added; A method of evaporating water by placing an aqueous dispersion of polymer particles in a reduced-pressure atmosphere; a method of heating the aqueous dispersion of colored polymer particles with an external heat exchanger and injecting into the reduced-pressure atmosphere to flush the aqueous dispersion of colored polymer particles; A method in which the dispersion is supplied from the top of the distillation tower and the aqueous dispersion is heated at the bottom of the tower or steam is blown into the aqueous dispersion to perform distillation. In order to remove volatile components, the temperature of the aqueous dispersion is usually (melting temperature of colored polymer particles -15) ° C to 100 ° C, preferably 60 to 90 ° C. The pressure for removing volatile components is usually 10 to 101 kPa, preferably 2 to 10 kPa.
0 to 70 kPa.

The removal of volatile components is carried out until the amount of unreacted monomer contained in the dried toner is usually 100 ppm or less, preferably 50 ppm or less. The amount of unreacted monomer was measured by the following method. That is, 0.7 g of the toner after drying is precisely weighed to a unit of 1 mg, methanol is added thereto, and the mixture is dispersed by ultrasonic waves.
and extracted at room temperature for 24 hours. Then, after insoluble matter was precipitated by centrifugation,
1 by gas chromatography (column: TC-WAX, 0. 1).
25 mm × 30 m; Column temperature: 80 ° C .; Injection temperature: 200 ° C., FID detection side temperature: 200 ° C.), and the amount of monomer was measured. The standard sample for quantification was a methanol solution of each monomer.

Examples of the water-soluble component include a dispersion stabilizer (a poorly water-soluble metal compound becomes water-soluble by an acid or an alkali) and a water-soluble oxo acid salt. The water-soluble component can be removed by removing the volatile component if the water-soluble component has high volatility. Water-soluble components having low volatility can be removed by washing such as acid washing, alkali washing, and water washing. The acid washing or the alkali washing is performed to remove a substance which becomes insoluble or hardly water-soluble in a neutral region and becomes water-soluble in an acidic or alkaline region. The acid or alkali washing method is not particularly limited.
For example, a method in which an acid or an alkali is added to the dispersion and stirring is performed; a method in which the dispersion is dehydrated into a cake and then an acid or an alkali is sprayed on the cake, and the like. In the acid washing, it is preferable to adjust the pH of the aqueous dispersion to 6.5 or less. For adjustment, a mineral acid such as sulfuric acid or hydrochloric acid; or an organic acid such as carboxylic acid is used. Particularly, sulfuric acid is preferred. In the alkali cleaning, ammonia, amines, alkali metal hydroxide, and the like are used. The water washing is performed to remove water-soluble substances in the neutral region and to return the medium that has become acidic or alkaline in the acid or alkaline washing to the neutral region. Specific examples of the water washing method include a method in which the dispersion is dehydrated into a cake, which is dispersed in the wash water and stirred; a method in which the dispersion is dehydrated into a cake and then sprayed with the wash water. Can be

The method for dehydrating the dispersion is not particularly limited.
For example, a method such as pressure filtration, vacuum filtration, or centrifugal filtration may be used. Among these, the centrifugal filtration method is preferred. Examples of the filtration and dewatering device include a peeler centrifuge, a siphon peeler centrifuge, and the like. In centrifugal filtration, centrifugal gravity is usually 400
-3000G, preferably 800-2000G. The water content after dehydration is usually 5 to 30% by weight, preferably 8 to 25% by weight. If the water content is high, the drying step requires a long time, and even if the impurity concentration in the water is low, if the water content is high, the impurities are concentrated by drying, and the environment dependency of the developer increases. The water content was determined by collecting 2 g of water-containing particles in an aluminum dish and weighing it (W ₀ [g]).
Then, it was left in a dryer set at 105 ° C. for 1 hour, cooled, precisely weighed (W ₁ [g]), and calculated by the following equation. Water content = ((W ₀ −W ₁ ) / W ₀ ) × 100 The method of spraying water on the cake-like colored polymer particles is not particularly limited. For example, a method in which a cake of colored polymer particles is placed on a belt filter, water is allowed to fall from above, and water is sucked from below the filter.

The removal of the water-soluble component is carried out by dehydrating and drying the colored polymer particles, and the conductivity of the particles obtained is usually 2
0 μS / cm or less, preferably 15 μS / cm or less,
σ2−σ1 is 10 μS / cm or less, preferably 5 μS / cm
/ Cm or less. The conductivity σ1 of water is usually 0 to 15 μS / cm. When σ2 is large or σ2-σ1 is large, the dependence of the charge amount on the environment increases, and environmental fluctuations (changes in temperature and humidity) occur.
Causes the image quality to deteriorate. Conductivity σ2
Means that 6 g of the dried toner is ion-exchanged water 1 having conductivity σ1.
After the dispersion was boiled for 10 minutes, ion-exchanged water, which had been separately boiled for 10 minutes, was added to return to the volume before boiling, and cooled to room temperature. It is a value measured by a total.

When a boron or phosphorus compound is contained as a water-soluble component, the content of boron or phosphorus is usually 0.1 to 100 ppm, preferably 0.2 to 50 pp.
m, more preferably 0.5 to 10 ppm. When the content of boron or phosphorus is small, poor image quality such as white streaks is likely to occur, and when the content is high, the image quality deteriorates when the temperature or humidity fluctuates. The content of boron or phosphorus is a value measured by the following method. That is, 5 g of the dried toner is added to 1
Put in a 00ml plastic container and add 50m of ion-exchanged water
1 was added and shaken to disperse the toner. Then 9
The container was immersed in hot water at 0 ° C., heated, and shaken for 30 minutes. Next, the solution was filtered through a 0.4 μ filter, and the filtrate was quantified for boron or phosphorus by ion chromatography to determine the content in the toner.

When acid or alkali washing is performed, the pH of the toner after drying is usually 4 to 8, preferably 4.5 to 4.5.
7.5. The pH was determined by dispersing 6 g of the toner in 100 g of ion-exchanged water (which had been subjected to a cation exchange treatment and an anion exchange treatment), and after boiling this for 10 minutes,
It is a value measured by using a pH meter after returning to the volume before boiling by adding ion-exchanged water separately boiled for 10 minutes, cooling to room temperature.

In the method for producing a toner of the present invention, after removing a volatile component or a water-soluble component from an aqueous dispersion of colored polymer particles, it is usually dehydrated and dried, and if necessary, classified. As the dehydration method, the same method as the dehydration method in the washing step can be adopted. In drying, water is removed by heating to a temperature at which the colored polymer particles do not fuse. Examples of the drying method include fluidized drying and vacuum drying, and are not particularly limited, but vacuum drying capable of drying at a low temperature is preferable, and drying with a vacuum dryer equipped with a stirring blade is particularly preferable. When the water content reaches about 60%, the following inorganic particles are added into the dryer, and the inorganic particles are dried while being mixed with the colored polymer particles, whereby the aggregation of the colored polymer particles is suppressed and the ratio of the coarse particles is reduced. And image quality defects such as white streaks can be reduced. The colored polymer particles obtained by this drying can be used as a toner as it is, but a toner obtained by adding an external additive to the surface of the colored polymer particles is usually used as the toner.

Examples of the external additive include inorganic particles and organic resin particles. Examples of the inorganic particles include silicon dioxide, aluminum oxide, titanium oxide, zinc oxide, tin oxide, barium titanate, and strontium titanate.
As the organic resin particles, methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles, the core is a shell of a methacrylic acid ester copolymer Are core-shell type polymer particles formed of a styrene polymer, core-shell type polymer particles formed of a methacrylate ester copolymer and a core of a styrene polymer, and the like. Of these, inorganic oxide particles, particularly silicon dioxide particles, are preferred. Moreover, the surface of these particles can be subjected to a hydrophobic treatment, and silicon dioxide particles subjected to the hydrophobic treatment are particularly suitable. The amount of the external additive is not particularly limited, but is usually 0.1 to 6 parts by weight based on 100 parts by weight of the colored polymer particles.

The external additives may be used in combination of two or more kinds. When using an external additive in combination, it is preferable to combine two types of inorganic oxide particles or organic resin particles having different average particle diameters. Specifically, particles having an average particle diameter of 5 to 20 nm, preferably 7 to 18 nm (preferably inorganic oxide particles), and an average particle diameter of more than 20 nm and 2 μm
Hereinafter, it is preferable that particles (preferably inorganic oxide particles) having a diameter of 30 nm to 1 μm are combined and adhered. The average particle diameter of the particles for the external additive is an average value of the measured values obtained by observing the particles with a transmission electron microscope, randomly selecting 100 particles and measuring the particle diameter.
The amount of the two types of external additives (particles) is
For 0 parts by weight, particles having an average particle diameter of 5 to 20 nm
Usually, 0.1 to 3 parts by weight, preferably 0.2 to 2 parts by weight, particles having an average particle diameter of more than 20 nm and 2 μm or less are usually 0.1 to 3 parts by weight, preferably 0.2 to 2 parts by weight. It is. Average particle size 5-20nm particle and average particle size 20n
The weight ratio of the particles having a particle diameter of more than m and 2 μm or less is usually 1: 5 to
It is in the range of 5: 1, preferably in the range of 3:10 to 10: 3. The attachment of the external additive is usually carried out by stirring the external additive and the colored polymer particles in a mixer such as a Henschel mixer. The toner obtained by the production method of the present invention can be applied to either a non-magnetic system or a magnetic system as a one-component developer or as a two-component developer in combination with a carrier.

[0031]

EXAMPLES The production method of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Parts and percentages are by weight unless otherwise specified. The evaluation performed in this example was performed by the following method. (Ratio of Coarse Powder) The volume average particle diameter (dv), the ratio of coarse powder and the ratio of fine powder of the polymer particles (toner particles) are measured by a particle size distribution measuring device (SALD2000A type, manufactured by Shimadzu Corporation).
Was measured by In the measurement by this particle size distribution measuring device, the refractive index was 1.55-0.20i, the ultrasonic irradiation time was 5 minutes, and distilled water was used as a dispersion medium at the time of particle size measurement. From the integrated curve of the volume average particle diameter obtained by using this measuring device, the ratio of more than 16 μm was determined as the coarse powder ratio (% by weight).
Asked.

(Print White Streaks and Fog) Using a commercially available non-magnetic one-component developing system printer (12-sheet machine), put the toner to be evaluated in the developing device of this printer,
In a 3 ° C. and 50% humidity environment—After standing day and night, continuous printing is performed on recycled paper, and when a certain number of sheets are reached, black solid printing is performed, and the presence or absence of white streaks and fog is observed. -B: Good -C: Somewhat poor evaluation was made. The final number of printed sheets was 20,000. In addition, continuous printing was performed at a printing density of 5%, and white streaks were examined every 500 sheets. (Clogging situation of heat exchanger) Colored polymer particle aqueous dispersion
After passing through a heat exchanger provided outside the evaporating tank at 60 m ³ / Hr for 10 hours, the amount of polymer particles attached near the supply port of the heat exchanger was measured. "A" for less than 1 kg, 1
"B" for more than 10kg and "C" for more than 10kg
Was evaluated.

Example 1 80.5 parts of styrene and n-butyl acrylate
A core polymerizable monomer composed of 5 parts (Tg of a copolymer obtained by copolymerizing these monomers = 55 ° C.), a polymethacrylate macromonomer (manufactured by Toa Gosei Chemical Industry Co., Ltd. 0.3 parts, divinylbenzene 0.5 parts, t-dodecyl mercaptan
2 parts, carbon black (Mitsubishi Chemical Corporation, trade name "# 2
5B "), 7 parts, charge control agent (Hodogaya Chemical Co., Ltd., trade name" Spiron Black TRH "), 1 part, release agent (Fischer Tropsch Wax, manufactured by Sasol Co., Ltd., trade name" Paraflint Spray 30 ", endothermic peak] Temperature: 100
C) 2 parts was wet-pulverized using a media-type wet pulverizer to obtain a core polymerizable monomer composition A. On the other hand, an aqueous solution obtained by dissolving 10.2 parts of magnesium chloride (water-soluble polyvalent metal salt) in 250 parts of ion-exchanged water was mixed with 50 parts of ion-exchanged water.
Aqueous solution in which 6.2 parts of sodium hydroxide (alkali metal hydroxide) was dissolved was gradually added with stirring to prepare a magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) dispersion liquid A. .

On the other hand, methyl methacrylate (Tg = 10
(5 ° C.) 2 parts of water and 65 parts of water were finely dispersed by an ultrasonic emulsifier to obtain an aqueous dispersion A of a polymerizable monomer for shell. A magnesium hydroxide colloid dispersion A was charged into a stirring tank having an inner diameter (D) of 205 mm in which 45-degree inclined paddle blades having an air diameter (2d) of 103 mm were arranged in two stages, and a polymerizable monomer composition A for a core was charged therein. And 6 parts of t-butylperoxy-2-ethylhexanoate (trade name "Perbutyl O", manufactured by NOF Corporation) and 1 part of sodium tetraborate decahydrate were added thereto. This was finely dispersed with Ebara Milder (trade name: MDN303V, manufactured by Ebara Corporation) to granulate a droplet of the monomer composition.

The aqueous dispersion of the granulated monomer composition was transferred to a polymerization reactor and heated to 90 ° C. to start a polymerization reaction. After the polymerization conversion reached almost 100%, the aqueous dispersion A of the polymerizable monomer for shell was added to a water-soluble initiator (trade name “VA-086” = 2,2′-, manufactured by Wako Pure Chemical Industries, Ltd.). 0.3 parts of azobis (2-methyl-N- (2-hydroxyethyl) -propionamide) were dissolved and placed in the reactor. After the polymerization was continued for 4 hours, the reaction was stopped to obtain an aqueous dispersion of polymer particles. The aqueous dispersion of the polymer particles is
Using the centrifugal pump shown in FIG. 1, the sample was transferred to an evaporation tank. The pressure in the evaporating tank was reduced to 25 kPa, the dispersion was withdrawn from the bottom of the tank, heated to 70 ° C. by an external heat exchanger, and flushed from the top of the evaporating tank. The centrifugal pump shown in FIG. 1 was used to transfer the dispersion from the bottom of the tank to the heat exchanger. In this evaporation tank, volatile components were removed so that the amount of unreacted monomers in the toner after drying was 100 ppm or less. Next, the polymer particle aqueous dispersion is transferred from the evaporating tank to the acid washing tank using a centrifugal pump, and sulfuric acid is added to the acid washing tank until the pH becomes 4 and acid washed, and dehydrated by a centrifugal filter to form a cake. Then, the cake was transferred to a water washing tank, re-dispersed by adding water, and washed with water. In the water washing tank, the conductivity σ2 of the dried toner is about 8 μS / cm,
1 is about 1 μS / cm, pH is about 6.6, and boron content is about 1
The water-soluble component was removed so as to become ppm. After washing with water,
The polymer was dehydrated with a centrifugal filter and dried under vacuum to obtain polymer particles. To 100 parts of the obtained particles, 0.6 part of colloidal silica (trade name “RX-100”, manufactured by Nippon Aerosil Co., Ltd.) was added and mixed with a Henschel mixer to obtain a toner. Table 1 shows the evaluation results.

[0036]

[Table 1]

Example 2 A toner was obtained in the same manner as in Example 1 except that the temperature in the heat exchanger was 90 ° C. Table 1 shows the evaluation results. Comparative Example A toner was obtained in the same manner as in Example 1 except that a diaphragm pump was used to transfer the aqueous dispersion of polymer particles. Table 1 shows the evaluation results.

[0038]

According to the production method of the present invention, generation of coarse particles is suppressed, and a toner having a sharp particle size distribution can be obtained, and an image free of white stripes and fog can be obtained by the toner. Further, there is little operational trouble such as clogging of the pipe, and the toner can be manufactured efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a centrifugal pump used in the production method of the present invention.

FIG. 2 is an enlarged view of a seal portion of the centrifugal pump of FIG.

FIG. 3 is a front view of an impeller of the centrifugal pump of FIG. 1;

[Explanation of symbols]

 1: Casing 2: Suction port 3: Impeller 9: Main shaft 4: Mechanical seal part 5: Discharge port 14: Fixed ring 15: Rotating ring

Claims (3)

[Claims] 1. A step of preparing an aqueous dispersion of colored polymer particles, transferring the aqueous dispersion of colored polymer particles using a turbo-type pump, and removing volatile components and / or water-soluble components from the polymer particles. A method for producing a toner, comprising: 2. The method according to claim 1, wherein the turbo pump is a centrifugal pump. 3. In order to feed the aqueous dispersion of colored polymer particles to a step for removing volatile components or water-soluble components,
To transfer from the step for removing volatile components or water-soluble components to the next step, or to circulate the aqueous dispersion of colored polymer particles in the process for removing volatile components or water-soluble components, 2. The method according to claim 1, wherein a turbo pump is used.