JP2000292976A - Toner and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner capable of stably forming sharp images even in the case of successively forming images for a long time under an environment of a high temperature and a high humidity. SOLUTION: This toner has toner particles obtained by adding water to solid grains produced by salting out and melt-attaching at least fine resin particles and fine colorant particles, while centrifugally separating solids from liquids, and feeding water until the electric conductivity of the separated liquid becomes <=50 μS/cm to wash the solids, and drying the solids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a toner and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a technique for producing a toner for developing an electrostatic latent image by a polymerization method is known. For example, toner particles are obtained by a suspension polymerization method. However, the toner particles obtained by the suspension polymerization method are spherical,
There is a disadvantage that cleaning performance is poor. On the other hand, as a method for obtaining irregular (non-spherical) toner particles, a dispersion is prepared by dispersing resin fine particles and colorant fine particles obtained by an emulsion polymerization method in an aqueous medium. A method of associating (aggregating and fusing) resin fine particles and colorant fine particles is known (for example, JP-A-60-2).
No. 25170). According to such a method, irregular (non-spherical) toner particles can be obtained, and a colorant is not added when performing emulsion polymerization for obtaining resin fine particles. And oligomers are advantageously reduced.

[0003] In the above emulsion polymerization method, a surfactant is used in emulsion polymerization for obtaining resin fine particles, and in addition, colorant fine particles and a so-called internal additive are added to an aqueous medium. Since a surfactant is used for dispersing, a large amount of a surfactant is required for preparing a dispersion. Therefore, in the production of a toner utilizing emulsion polymerization, a particulate solid obtained by associating (aggregating and fusing) the resin fine particles and the colorant fine particles is separated from the dispersion medium by filtration, and then separated. It has been done to clean things. As a method of washing the particulate solid, a method of redispersing the solid in water and then filtering the obtained dispersion to repeat a step of separating the particulate solid from water is repeated. It is known (see JP-A-8-248676).

However, in such a method, impurities such as a surfactant and a decomposition product of a polymerization initiator naturally exist in a dispersion obtained by redispersing a solid substance. The impurities remain in the solid obtained by filtering this. Then, by repeatedly redispersing the solid and filtering the dispersion, the concentration of the impurity in the solid gradually decreases, but it is difficult to sufficiently remove the impurity.

As described above, in the conventional method, since it is necessary to repeatedly redisperse the solid and filter the dispersion, the washing operation is complicated, and it is difficult to obtain a toner with few impurities. Met. When a toner containing such impurities is used in a high-temperature and high-humidity environment, the charge amount is reduced due to the influence of impurities such as a surfactant, or the amount of impurities existing on the surface between toner particles is reduced. Due to the variation, the distribution of the charge amount of the toner is widened, so that there is a problem that a fog occurs and a sharp image cannot be obtained.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
An object of the present invention is to provide a toner capable of stably obtaining a sharp image even when an image is continuously formed for a long time in a high temperature and high humidity environment. Another object of the present invention is to provide a method capable of producing a toner capable of stably obtaining a sharp image even when an image is continuously formed for a long time in a high temperature and high humidity environment. It is in.

[0007]

The toner of the present invention is obtained by subjecting at least solid particles obtained by salting out / fusing resin fine particles and colorant fine particles to solid-liquid separation by centrifugation. The solid is washed by supplying water until the conductivity of the filtrate becomes 50 μS / cm or less, and thereafter, the toner is obtained by drying the solid.

In the method for producing a toner according to the present invention, the solids and liquids obtained by salting out and fusing at least resin fine particles and colorant fine particles are subjected to solid-liquid separation by centrifugation while the filtrate is subjected to solid-liquid separation. The method includes a step of washing the solid by supplying water until the conductivity becomes 50 μS / cm or less, and then drying the solid to obtain toner particles.

In the above-described method for producing a toner, the acceleration in the centrifugal separation is preferably 500 to 1000 G.

[0010]

By supplying water to a particulate solid obtained by salting out / fusing while performing solid separation by centrifugation, the solid is washed with fresh water constantly renewed. And the conductivity of the filtrate is 50 μS /
cm, the impurities contained in the solid matter can be sufficiently and efficiently removed.

[0011]

Embodiments of the present invention will be described below in detail. In the toner of the present invention, a mixed dispersion containing at least resin fine particles and colorant fine particles is prepared, and the resin fine particles and the colorant fine particles in the mixed dispersion are salted out using a salting-out agent. The solids are washed by supplying water while performing solid-liquid separation by centrifugation on the particulate solids obtained by fusion and salting-out / fusion, and then washing the solids. Has toner particles obtained by drying. In the above, the mixed dispersion is obtained, for example, by mixing the resin fine particle dispersion and the colorant fine particle dispersion.

<Resin Particle Dispersion> A resin particle dispersion is obtained by emulsion polymerization of a polymerizable monomer for obtaining the resin particles. As such a polymerizable monomer, a radical polymerizable monomer is an essential component, and a crosslinking agent can be used as necessary. In addition, as a part of the radical polymerizable monomer, at least one monomer selected from a radical polymerizable monomer having an acidic group and a radical polymerizable monomer having a basic group is used. Is preferred.

(1) Radical polymerizable monomer: The radical polymerizable monomer is not particularly limited, and one type of conventionally known radical polymerizable monomer may be used according to the required characteristics. Alternatively, two or more kinds can be used in combination. Such radical polymerizable monomers include aromatic vinyl monomers, (meth) acrylate monomers,
Vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers, halogenated olefin monomers and the like can be used.

Specific examples of the aromatic vinyl monomer include:
For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene,
p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, pn-butylstyrene, p-tert-
Butylstyrene, pn-hexylstyrene, pn-
Octylstyrene, pn-nonylstyrene, pn-
Decylstyrene, pn-dodecylstyrene, 2,4-
Styrene-based monomers such as dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

Specific examples of (meth) acrylate monomers include methyl acrylate, ethyl acrylate,
Butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, methacryl Dimethylaminoethyl acrylate, diethylaminoethyl methacrylate and the like.

Specific examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl benzoate and the like.

Specific examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

Specific examples of the monoolefin-based monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

Specific examples of the diolefin monomer include:
Butadiene, isoprene, chloroprene and the like.

Specific examples of the halogenated olefin-based monomer include vinyl chloride, vinylidene chloride, vinyl bromide and the like.

(2) Crosslinking agent: A radical polymerizable crosslinking agent may be added as a crosslinking agent for improving the properties of the toner. Specific examples of such a radical polymerizable crosslinking agent include:
Examples thereof include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Radical polymerizable monomer having an acidic group: Examples of the radical polymerizable monomer having an acidic group include a carboxyl group-containing monomer and a sulfonic acid group-containing monomer. Can be. Specific examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monobutyl maleate, and monooctyl maleate. Specific examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfosuccinic acid, octyl allyl sulfosuccinate, and the like. All or part of the radical polymerizable monomer having such an acidic group may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium.

(4) Radical polymerizable monomer having a basic group: Examples of the radical polymerizable monomer having a basic group include primary amine, secondary amine, tertiary amine, and quaternary amine.
An amine compound such as a quaternary ammonium salt can be used. Specific examples of such an amine compound include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and quaternary ammonium salts thereof, 3-dimethylaminophenyl acrylate, 2-hydroxy-3- Methacryloxypropyltrimethylammonium salt, acrylamide, N-
Butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N
-Butylmethacrylamide, N-octadecylacrylamide; vinylpyridine, vinylpyrrolidone; vinyl N
-Methylpyridinium chloride, vinyl N-ethylpyridinium chloride, N, N-diallylmethylammonium chloride, N, N-diallylethylammonium chloride and the like.

In the above, the proportion of the radical polymerizable crosslinking agent used is preferably in the range of 0.1 to 10% by weight of the total polymerizable monomer. The total usage ratio of the radical polymerizable monomer having an acidic group and the radical polymerizable monomer having a basic group is 0.1 to 2 of the total polymerizable monomer.
It is preferably 0% by weight, particularly preferably 0.1 to 15% by weight.

[Chain transfer agent] For the purpose of adjusting the molecular weight of the polymer constituting the resin fine particles, a chain transfer agent generally used can be used. Such chain transfer agents are not particularly limited, and include, for example, octyl mercaptan, dodecyl mercaptan, tert
-Mercaptans such as dodecyl mercaptan, styrene dimers and the like can be used.

[Polymerization Initiator] The radical polymerization initiator for polymerizing the monomer can be appropriately used as long as it is water-soluble. Specific examples of such radical polymerization initiators include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis ( 2-amidinopropane) salts, etc.), peroxide compounds and the like. Further, the above radical polymerization initiator can be used as a redox initiator in combination with a reducing agent, if necessary. By using such a redox initiator, the polymerization activity is increased, so that the polymerization temperature can be lowered and the polymerization time can be further shortened.

[Surfactant] The surfactant used for emulsion polymerization of the polymerizable monomer is not particularly limited, but a sulfonate (sodium dodecylbenzenesulfonate, arylalkyl poly Sodium sulfonate), sulfates (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.),
Suitable examples include ionic surfactants such as fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate, etc.).

Further, as the surfactant, a nonionic surfactant can be used, and specific examples thereof include:
Polyethylene oxide, polypropylene oxide,
Combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol,
Esters of higher fatty acids and polypropylene oxide, sorbitan esters and the like can be mentioned. These surfactants are used as emulsifiers in emulsion polymerization, but may be used for other steps or purposes.

[Emulsion polymerization step] As a method of emulsion-polymerizing the above-mentioned polymerizable monomer, a conventionally known emulsion polymerization method can be basically used. As an example of the emulsion polymerization method, a predetermined amount of a radical polymerization initiator is dissolved in an aqueous medium (aqueous solution of a surfactant), degassed by a nitrogen stream, heated, and reaches a predetermined temperature (polymerization temperature). At this point, a radical polymerizable monomer is added. In the above, when a chain transfer agent is used for controlling the molecular weight, it is preferable to add the chain transfer initiator by mixing it with the polymerizable monomer. The polymerization temperature is not particularly limited as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator used, but is, for example, in the range of 50 to 90 ° C. However, by using a polymerization initiator started at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (such as ascorbic acid), polymerization can be performed at room temperature or higher. The emulsion polymerization is usually performed under a nitrogen stream.

[Resin Fine Particles] The resin fine particles in the dispersion thus obtained have a glass transition point (Tg) of 1
It is preferably in the range of 0 to 75 ° C, more preferably 40 to 65 ° C. Here, the glass transition point (Tg) of the resin fine particles refers to a value measured by DSC, and the intersection between the baseline and the slope of the endothermic peak is defined as the glass transition point. Specifically, using a differential scanning calorimeter,
Temperature, and leave it at that temperature for 3 minutes.
Cool to room temperature at 0 ° C./min. Next, when this sample was measured at a heating rate of 10 ° C./min, an extension line of the base line below the glass transition point and a tangent line showing the maximum slope from the rising portion of the peak to the top of the peak. The intersection is indicated as the glass transition point. Here, as a measuring device, DSC-7 manufactured by Perkin Elmer, or the like can be used.

The softening point of the fine resin particles is 80 to 220.
It is preferably in the range of ° C. Here, the softening point of the resin fine particles means a value measured using a Koka type flow tester. Specifically, the Koka type flow tester “CF
T-500 "(manufactured by Shimadzu Corporation) was used to melt and flow out a 1 cm ³ sample under the conditions of a die having a pore diameter of 1 mm, a length of 1 mm, a load of 20 kg / cm ² , and a heating rate of 6 ° C./min. The total descending distance of the plunger from the outflow start point to the outflow end point is measured, and the temperature when the plunger has descended a half of the total descending distance is obtained, and this temperature is defined as the softening point.

The resin fine particles preferably have a weight average particle diameter of 20 to 500 nm, particularly preferably 30 to 400 nm. Here, the particle size of the resin fine particles was determined using an electrophoretic light scattering photometer ELS-800 manufactured by Otsuka Electronics Co., Ltd.
3 shows a weight average particle diameter measured using a resin fine particle dispersion.

The molecular weight of the resin fine particles is not particularly limited, but preferred resin fine particles are composed of a low molecular weight resin component and a high molecular weight resin component, and the low molecular weight resin component has a peak molecular weight of 1,000 to 30. 000,
The high molecular weight resin component has a peak molecular weight of 50,0.
00 to 1,000,000. The ratio between the high molecular weight resin component and the low molecular weight resin component is not particularly limited, but it is preferable that the high molecular weight resin component / the low molecular weight resin component = 1/1 to 1/10 by weight. . If the proportion of the low molecular weight resin component is too small, the adhesiveness to the image support may decrease. On the other hand, when the ratio of the low-molecular-weight resin component is excessive, the offset property and the winding property may be reduced.

Here, the molecular weight of the resin fine particles indicates the molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) using THF (tetrahydrafuran) as a solvent. More specifically, 1 cc of THF is added to 0.5 to 5 mg of the measurement sample, more specifically 1 mg, and the sample is sufficiently stirred in THF by stirring with a magnetic stirrer or the like at room temperature. Allow to dissolve. Next, this solution is treated with a membrane filter having a pore size of 0.45 to 0.50 μm, and then injected into a GPC column.

GPC measurement conditions were as follows: the column was stabilized at 40 ° C., and THF was flowed at a flow rate of 1 cc / min.
About 100 μl of a sample having a concentration of 1 mg / cc is injected into a GPC column for measurement. The column is preferably used in combination with a commercially available polystyrene gel column.
For example, Shodex GPC KF-
801,802,803,804,805,806,8
07 combination or TSKgelG1000 manufactured by Tosoh Corporation
H, G2000H, G3000H, G4000H, G5
000H, G6000H, G7000H, TSKgua
rdcolumn and the like.
Further, as the detector, a refractive index detector (IR detector),
Alternatively, it is preferable to use a UV detector. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. As polystyrene for preparing a calibration curve, about 10 points may be used.

As the resin fine particles, it is preferable to use composite resin fine particles having a core / shell structure having a high molecular weight resin component as a core and a low molecular weight resin component as a shell. By using these composite resin fine particles, it is possible to obtain a toner having excellent uniformity in composition, molecular weight, and surface characteristics among toner particles. As a method for obtaining such composite resin fine particles, a core particle (i) composed of a high molecular weight resin component is formed by an emulsion polymerization method (first step), and a dispersion of the core particles (i) is added to a polymerization initiator. And a monomer mixture (a polymerizable monomer for obtaining a low molecular weight resin), and then subjecting the system to an emulsion polymerization treatment (second stage) to obtain the core particles (i).
(A two-stage polymerization method) in which a shell (ii) made of a polymer of a monomer mixture is formed on the surface of the polymer. In addition,
The “shell” constituting the composite resin fine particles may be not only one layer but also two or more layers. In this case, the outermost layer is preferably made of a low molecular weight resin.

<Colorant Fine Particle Dispersion> The colorant fine particle dispersion is obtained by dispersing colorant fine particles in, for example, an aqueous medium containing a surfactant.

Various inorganic pigments and organic pigments can be used as the colorant fine particles. Conventionally known inorganic pigments can be used. Although any pigment can be used, specific inorganic pigments are exemplified below. As the black pigment, for example, carbon black such as furnace black, channel black, acetylene black, thermal black and lamp black, and magnetic powder such as magnetite and ferrite are also used. These inorganic pigments can be used alone or in combination of two or more as desired.

When an inorganic pigment is used as the colorant fine particles, the use ratio of the colorant fine particles is preferably 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight based on 100 parts by weight of the resin fine particles. In the case of forming a magnetic toner, the above-mentioned magnetite can be suitably used, and its use ratio is preferably 20 to 60% by weight of the whole toner particles from the viewpoint of exhibiting predetermined magnetic characteristics. preferable.

As the organic pigment, conventionally known organic pigments can be used. Although any pigment can be used, specific organic pigments are exemplified below. Pigments for magenta or red include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I.
Pigment Red 7, C.I. I. Pigment Red 15,
C. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1,
C. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123,
C. I. Pigment Red 139, C.I. I. Pigment red 144, C.I. I. Pigment Red 149, C.I.
I. Pigment Red 166, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I.
Pigment Red 222 and the like. Examples of orange or yellow pigments include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I.
Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 1
7, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 13
8, and the like. Green or cyan pigments include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 1
5: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like. These organic pigments can be used alone or in combination of two or more as desired.

When an organic pigment is used as the colorant fine particles, the use ratio of the colorant fine particles is preferably 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, per 100 parts by weight of the resin fine particles.

As the colorant fine particles, surface-modified fine particles can be appropriately used. Here, conventionally known surface modifiers can be used, and specifically, silane coupling agents, titanium coupling agents, aluminum coupling agents, and the like can be preferably used.

Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyl Trichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane,
γ-ureidopropyltriethoxysilane and the like.

As the titanium coupling agent, for example,
TTS, 9S, 38S, 41B, 46B, 5B, which are commercially available under the trade name "Plenact" manufactured by Ajinomoto Co.
5, 138S, 238S, etc., commercial products A-
1, B-1, TOT, TST, TAA, TAT, TL
A, TOG, TBSTA, A-10, TBT, B-2,
B-4, B-7, B-10, TBSTA-400, TT
S, TOA-30, TSDMA, TTAB, TTOP and the like. As the aluminum coupling agent,
For example, "Plenact AL-M" manufactured by Ajinomoto Co., Inc., and the like can be mentioned.

The use ratio of these surface modifiers is preferably from 0.01 to 20% by weight, more preferably from 0.1 to 5% by weight, based on the colorant fine particles. As a surface modification method of the colorant fine particles, a dispersion is prepared by dispersing the colorant fine particles in an appropriate dispersion medium, a surface modifier is added to the dispersion, and the system is heated. A reaction method can be used. The colorant fine particles whose surface has been modified are collected by filtration, dried after the washing treatment with the dispersion medium and the filtration treatment are repeated, and then dried.

As the surfactant for preparing the colorant fine particle dispersion, the same surfactants as those used for preparing the above-mentioned resin fine particle dispersion can be used.
This surfactant is used in a ratio that is equal to or higher than the critical micelle concentration (CMC).

The disperser for preparing the colorant fine particle dispersion is not particularly limited, and various dispersers can be used. Preferred dispersers are an ultrasonic disperser, a mechanical homogenizer, a Manton-Gaulin or a pressure type. Examples thereof include a pressure disperser such as a homogenizer and a medium disperser such as a Getzman mill and a diamond fine mill.

<Mixed Dispersion> A mixed dispersion is obtained by adding the above-mentioned colorant fine particle dispersion to the above resin fine particle dispersion and mixing them. The mixed dispersion may contain various internal additives as required in addition to the resin fine particles and the colorant fine particles. As such an internal additive, a fixing property improving agent, a charge control agent and the like can be used.

As the fixing property improving agent, various conventionally known fixing agents can be used as long as they can be dispersed in water. Specific examples thereof include polypropylene and polypropylene.
Examples thereof include olefin waxes such as polyethylene, modified products thereof, natural waxes such as carbawa wax and rice wax, and amide waxes such as fatty acid bisamide. The use ratio of the fixing property improving agent is, for example, 0.1 to 10 parts by weight based on 100 parts by weight of the resin fine particles.

As the charge control agent, various types of conventionally known charge control agents can be used as long as they can be dispersed in water. Specific examples thereof include a nigrosine dye,
Examples thereof include metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts, and metal complexes thereof. The usage ratio of the charge control agent is, for example, 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin fine particles.

These fixing property improving agents or charge control agents are preferably used in a state where the particles are dispersed in water, that is, in the form of a dispersion. Further, the particle size of the particles of the fixing property improving agent or the charge control agent in the dispersion liquid,
The number average primary particle diameter is preferably from 10 to 500 nm.

As the method of adding the internal additive, (a) a method of adding a dispersion of the internal additive at the stage of performing the emulsion polymerization of the radical polymerizable monomer for obtaining the resin fine particles described above;
Various methods such as (b) a method of adding a dispersion of an internal additive together with colorant fine particles to a resin fine particle dispersion, and (c) a method of adding an internal additive to the resin itself constituting the resin fine particles are employed. However, preferred methods include the above-mentioned method (a) or (b).

<Salt-out / fusion step> The resin fine particles, the colorant fine particles and the optional additives used in the mixed dispersion thus prepared are subjected to salt-out / fusion under appropriate conditions. (Simultaneous salting out and fusion). Specifically, in order to salt out / fuse the resin fine particles, the colorant fine particles, and the internal additive, a salting-out agent having a critical aggregation concentration or more is added to the mixed dispersion, and the dispersion is It is necessary to heat to a temperature higher than the glass transition point (Tg) of the resin fine particles.

As the salting-out agent, an alkali metal salt, an alkaline earth metal salt or the like can be used. Specific examples of the metal component constituting the salting-out agent include lithium, potassium, sodium and the like as alkali metals, and magnesium, calcium, strontium, barium and the like as alkaline earth metals. Among these,
Potassium, sodium, magnesium, calcium, barium are preferred. Examples of the anion serving as a counter ion of the metal component include chloride ion, bromide ion, iodide ion, carbonate ion, and sulfate ion.

The preferred temperature range for salting out / fusing is (Tg + 10) to (Tg + 50) ° C., particularly preferably (Tg + 15) to (Tg + 40) ° C. The temperature of the mixed dispersion when adding the salting-out agent to the mixed dispersion is determined by the glass transition point (Tg) of the resin fine particles.
Is preferably less than 5 ° C., specifically, preferably 5 to 55 ° C., and more preferably 10 to 45 ° C. When the temperature of the mixed dispersion at the time of adding the salting-out agent is equal to or higher than the glass transition point (Tg) of the resin fine particles, the salting-out proceeds rapidly, and it is difficult to control the particle size. Giant particles are easily generated.

For effective fusion, an organic solvent infinitely soluble in water is preferably added to the mixed dispersion to substantially lower the glass transition point (Tg) of the resin fine particles. Such “organic solvents that are infinitely soluble in water” include methanol, ethanol, 1-propanol, 2-
Propanol, ethylene glycol, glycerin, acetone and the like can be used. Among them, alcohols having 3 or less carbon atoms such as methanol, ethanol, 1-propanol and 2-propanol are preferable, and 2-propanol is particularly preferable.

As described above, in the salting-out / fusion step, the temperature of the mixed dispersion is adjusted to the glass transition point (T
g) In the following cases, it is necessary to add a salting-out agent to the mixed dispersion, and then immediately start heating the mixed dispersion to a temperature equal to or higher than the glass transition point (Tg) of the resin fine particles. It is.

After the salting-out agent was added to the mixed dispersion, the temperature of the mixed dispersion was changed to the glass transition point (T
The time required to reach the temperature of g) or higher is usually within 120 minutes, preferably within 60 minutes. If this time exceeds 120 minutes, the aggregation state of the aggregated particles (non-fused particles) due to salting out fluctuates, and the particle size distribution of the toner particles obtained by fusing the particles becomes broad,
The surface properties of the toner particles fluctuate.

The interval from the addition of the salting-out agent to the mixed dispersion to the start of heating the mixed dispersion is usually within 30 minutes, preferably within 15 minutes.

The rate of temperature rise of the mixed dispersion after adding the salting-out agent is preferably 0.25 to 0.5 ° C./min or more. When the rate of temperature rise is less than 0.25 ° C./min, it takes a long time for the temperature of the mixed dispersion to reach the glass transition point (Tg) or higher, so that salting out and fusion are simultaneously performed. It becomes difficult to make it. On the other hand, if the rate of temperature rise exceeds 0.5 ° C./min, salting out proceeds rapidly, making it difficult to control the particle size and tend to generate giant particles.

[Filtration / Washing Step] In the present invention, water is supplied to the particulate solid obtained by the above salting-out / fusion step while performing solid-liquid separation by centrifugation. The solid is washed. Specifically, the slurry containing the particulate solid is put into a tank of a centrifuge in which a tubular filter cloth is set, and by operating this centrifuge, the particles on the inner surface of the filter cloth. The wet cake is formed by forming a wet cake of solids and supplying water into the tank of the centrifuge.

In this filtration / washing step, the conductivity of the filtrate is 5
The process is performed until it becomes 0 μS / cm or less, preferably 30 μS / cm or less, and particularly preferably 20 μS / cm or less.
When the conductivity of the filtrate exceeds 50 μS / cm, the residual amount of impurities such as a surfactant is large. Therefore, when the obtained toner is used in a high-temperature and high-humidity environment, fog occurs and a sharp image is formed. Can not be obtained. The conductivity of the filtrate can be measured by a usual electric conductivity meter. As such an electric conductivity meter, "C" manufactured by Toa Denpa Kogyo KK
M-14P ".

The filter cloth used for centrifugation is not particularly limited, but is preferably one that can effectively hold a wet cake and that allows water to flow smoothly. . Water used for washing is not particularly limited, for example, well water,
Water such as tap water and ion-exchanged water can be used. However, in order to make the conductivity of the filtrate 50 μS / cm or less, finally, the low conductivity, for example, 10 μS / c
m or less of water is preferably used.

The acceleration during centrifugation is 500 to 10
00G, particularly preferably 600 to 800G.
If the acceleration is less than 500 G, it is difficult to uniformly supply the washing water over the entire wet cake of the particulate solid formed on the inner surface of the filter cloth, so that the conductivity of the filtrate is 50 μS /. cm or less, impurities such as a surfactant and a salting-out agent may partially remain. On the other hand, if the acceleration exceeds 1000 G, cracks are generated on the surface of the wet cake due to the particulate solids formed on the filter cloth, and the washing water flows out from the cracks, resulting in surfactants and salting out. It may be difficult to sufficiently remove impurities such as agents.

The supply amount of water used for washing is, for example, preferably 0.05 to 10 liters / minute, particularly preferably 0.1 to 5 liters / minute, per kg of solid matter. If the supply amount of water is too small, a sufficient washing effect is not exhibited, and even if the conductivity of the filtrate becomes low, impurities such as a surfactant and a salting-out agent may remain. .
On the other hand, when the supply amount of water is excessive, a high washing effect can be obtained, but since the water stays in the centrifugal separator, the surfactant or the salting-out agent once separated from the particulate solid matter. As a result, impurities such as may adhere to the solid again, and may remain on the solid.

[Drying Step] The solid particles thus filtered / washed are dried by an appropriate dryer to obtain toner particles. The dryer is not particularly limited, and includes, for example, a spray dryer, a vacuum freeze dryer, a vacuum dryer, a stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary dryer, a stirring dryer, and the like. Can be used. Among these, stationary shelf dryers,
A mobile shelf dryer, a fluidized bed dryer, a rotary dryer, a stirring dryer and the like are preferable. The water content of the toner particles obtained by this drying treatment is preferably 5% by weight or less, particularly preferably 2% by weight or less.

When the toner particles obtained by the drying process are aggregated by a weak attraction between the particles, the aggregate may be crushed. Here, as the crushing device, a mechanical crushing device such as a jet mill, a Henschel mixer, a coffee mill, and a food processor can be used.

The particle size of the toner particles thus obtained is preferably 3 to 10 μm in terms of volume average particle size. The volume average particle diameter of the toner is determined by using Coulter Counter TA-II, Coulter Multisizer, SLAD110
0 (a laser diffraction particle size analyzer manufactured by Shimadzu Corporation) or the like. Coulter counter TA
II and Coulter Multisizer use an aperture with an aperture diameter of 100 μm and 2.0 to 40 μm
Is measured using the particle size distribution in the range of.

The toner particles are irregular (non-spherical) particles having an average shape factor in the range of 1.3 to 2.2 and a shape factor of 1.5 to 2.2. It is preferable that the ratio of the toner particles in the range of 0 is 80% by number or more. Here, the “shape factor” of the toner particles means that the projected area of the toner particles in an electron micrograph photographed using a scanning electron microscope is S, and the maximum diameter is L.
Means the value represented by the following equation.

[0070]

Formula: Shape factor = [(L / 2) ² × π] / S

A specific method for measuring the shape factor is as follows.
It is as follows. 500 toner particles were photographed at a magnification of 500 times with a scanning electron microscope, and the resulting electron micrograph was referred to as “SCANNING IM”.
The image area is analyzed using “AGE ANALYSER” (manufactured by JEOL Ltd.) to measure the projected area and the maximum diameter of each toner particle, and the shape factor of each toner particle is calculated from the following equation. Then, the average value of the shape coefficients of 500 toner particles and the ratio (number%) of the toner particles having a shape coefficient of 1.5 to 2.0 in 500 toner particles are obtained.

<Toner> The above toner particles can be used as a toner as it is.
For the purpose of improving the charging property and the cleaning property, it is preferable to add a so-called external additive to the toner particles to prepare the toner. Such external additives are not particularly limited, and various inorganic fine particles, organic fine particles, and lubricants can be used.

Conventionally known inorganic fine particles can be used. Specifically, silica fine particles, titanium fine particles, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic. As silica fine particles, for example, Nippon Aerosil Co., Ltd.
Commercially available products R-805, R-976, R-974, R-
972, R-812, R-809, HVK-2150, H-200 manufactured by Hoechst Co., Ltd., and commercial products TS-720, TS-530, TS-610, H manufactured by Cabot Co., Ltd.
-5, MS-5 and the like. As the titanium fine particles, for example, a commercial product T-80 manufactured by Nippon Aerosil Co., Ltd.
5, T-604, commercially available MT-100 manufactured by Teika Co., Ltd.
S, MT-100B, MT-500BS, MT-60
0, MT-600SS, JA-1, commercially available TA-300SI, TA-500, TAF-1 manufactured by Fuji Titanium Co., Ltd.
30, TAF-510, TAF-510T, commercial products IT-S, IT-OA, IT-OB manufactured by Idemitsu Kosan Co., Ltd.
IT-OC and the like. As alumina fine particles,
For example, a commercial product RFY-C manufactured by Nippon Aerosil Co., Ltd.,
C-604, a commercial product TTO-55 manufactured by Ishihara Sangyo Co., Ltd., and the like.

The organic fine particles have a number average primary particle diameter of 1
Spherical organic fine particles of about 0 to 2000 nm can be used. As such organic fine particles, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

Examples of the lubricant include salts of zinc, aluminum, copper, magnesium, calcium and the like of stearic acid, salts of zinc, manganese, iron, copper and magnesium of oleic acid, and zinc, copper, magnesium and calcium of palmitic acid. Metal salts of higher fatty acids such as salts of linoleic acid such as zinc and calcium, and salts of ricinoleic acid such as zinc and calcium.

The use ratio of these external additives is preferably about 0.1 to 5% by weight based on the toner. In addition, as a device used for adding an external additive, a turbular mixer, a Hensiel mixer, a Nauter mixer, a V
Various known mixing devices such as a mold mixer can be used.

[Developer] The toner of the present invention can be used as a magnetic or non-magnetic one-component developer.
It may be used as a two-component developer by mixing with a carrier. When the toner of the present invention is used as a two-component developer, as the carrier, a conventionally known material such as iron, ferrite, a metal such as magnetite, or an alloy of such a metal with aluminum or a metal such as lead is used. be able to. Particularly, ferrite particles are preferable. The volume average particle size of the carrier is preferably from 15 to 100 μm, more preferably from 25 to 60 μm. The volume average particle size of the carrier is typically measured by a laser diffraction type particle size distribution analyzer “HELOS” equipped with a wet disperser.
(Manufactured by SYMPATEC).

Preferred carriers include a resin-coated carrier in which the surface of magnetic particles is coated with a resin, and a so-called resin-dispersed carrier in which magnetic particles are dispersed in a resin. The resin constituting the resin-coated carrier is not particularly limited, and examples thereof include an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, an ester resin, and a fluorine-containing polymer resin. The resin constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, styrene acrylic resin, polyester resin, fluorine resin, phenol resin and the like can be used.

[Developing System] The developing system to which the toner of the present invention is applied is not particularly limited. It can be suitably used for both the contact developing system and the non-contact developing system. In particular, the toner of the present invention has a high charge rising property and is useful for a non-contact developing method. That is, in the non-contact developing method, since the change in the developing electric field is large, a minute change in the charge is large and acts on the development itself.
For this reason, there is a large fluctuation with respect to a change in the charge amount of the toner. However, since the toner of the present invention has a high charge rising property, the change in charge is small, and a stable charge amount can be secured. Therefore, a stable image can be formed for a long time even by the non-contact developing method.

For the contact type development, the layer thickness of the developer having the toner of the present invention is 0.1 to 8 m in the development area.
m, particularly preferably 0.4 to 5 mm. Also,
The gap between the photoconductor and the developer carrier is preferably 0.15 to 7 mm, particularly preferably 0.2 to 4 mm.

In the non-contact type developing system, the developer layer formed on the developer carrying member does not come into contact with the photoreceptor. It is preferable to be formed by. In this method, a developer layer having a thickness of 20 to 500 μm is formed in a development region on the surface of the developer carrier, and a gap between the photoconductor and the developer carrier has a larger gap than the developer layer. The thin layer is formed by a magnetic blade using a magnetic force or a method of pressing a developer layer regulating rod against the surface of the developer carrier. further,
There is also a method in which a urethane blade, a phosphor bronze plate or the like is brought into contact with the surface of the developer carrier to regulate the developer layer. The pressing force of the pressing regulating member is preferably from 1 to 15 gf / mm. When the pressing force is small, the conveyance is likely to be unstable because the regulating force is insufficient. On the other hand, when the pressing force is large, the stress on the developer is increased, and the durability of the developer is likely to be reduced. A preferred range is 3 to 10 gf / mm. The gap between the developer carrier and the surface of the photoconductor needs to be larger than the developer layer. Furthermore, when a developing bias is applied during development, either a method of applying only a DC component or a method of applying an AC bias may be used. The diameter of the developer carrier is 10 to 40 m.
m is preferred. When the diameter is small, the mixing of the developer is insufficient, and it is difficult to ensure sufficient mixing to give sufficient charge to the toner. When the diameter is large, the centrifugal force on the developer becomes large. , The problem of toner scattering is likely to occur.

As the developer carrier used in the present invention, a developing device having a magnet built in the carrier is used, and the surface of the developer carrier is made of aluminum or aluminum whose surface is oxidized. Stainless steel is used.

[0083]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. <Preparation of Colorant Fine Particle Dispersion> 0.90 kg of sodium n-dodecyl sulfate “ADEKAHOPE LS-90” (manufactured by Asahi Denka Co., Ltd.) and 10.0 kg of ion-exchanged water are charged into a 20-liter resin container. The system is stirred and n-
An aqueous solution of sodium dodecyl sulfate was prepared. While stirring this aqueous solution, carbon black “REGAL 330”
R "(manufactured by Cabot Corporation) 1.20 kg was gradually added. After the addition, the mixture is stirred for 1 hour, and then the dispersion process of carbon black is continuously performed for 20 hours using a medium-type disperser, whereby a colorant fine particle dispersion (hereinafter, referred to as “colorant dispersion”)
It is referred to as “colorant fine particle dispersion (C)”. ) Was prepared.
The particle diameter of the colorant fine particles in the colorant fine particle dispersion liquid (C) is measured by using an electrophoretic light scattering photometer “ELS-800”.
It was 122 nm in weight average particle diameter when measured using (manufactured by Otsuka Electronics Co., Ltd.). The solid content concentration of the colorant fine particle dispersion measured by a gravimetric method by standing drying was 16.
It was 6% by weight.

<Preparation of Aqueous Solution of Surfactant> [Preparation Example (S-1)] Sodium dodecylbenzenesulfonate (manufactured by Kanto Chemical Co., Ltd.) as an anionic surfactant was placed in a stainless steel pot having an internal volume of 10 liters. 0.05
5 kg and 4.0 kg of ion-exchanged water were charged, and this system was stirred at room temperature to prepare an aqueous solution of an anionic surfactant (hereinafter, referred to as “surfactant solution (S-1)”). .

[Preparation Example (S-2)] A nonionic surfactant "Newcol 565C" (manufactured by Nippon Emulsifier Co., Ltd.) 0.014 k was placed in a stainless steel pot having a capacity of 10 liters.
g and 4.0 kg of ion-exchanged water, and the system was stirred at room temperature to prepare an aqueous solution of a nonionic surfactant (hereinafter, referred to as “surfactant solution (S-2)”). .

[Preparation Example (S-3)] A nonionic surfactant "FC-170" was placed in a 2-liter glass beaker.
C "(manufactured by Sumitomo 3M Limited) and 1.00 kg of ion-exchanged water, and the system was stirred at room temperature to obtain an aqueous solution of a nonionic surfactant (hereinafter referred to as" surfactant solution (S -3) ").

<Preparation of Aqueous Solution of Polymerization Initiator> [Preparation Example (P-1)] In a 20 liter hollow pot, 200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) as a polymerization initiator was added. An aqueous solution of a polymerization initiator (hereinafter, referred to as “initiator solution (P-1)”) was prepared by charging 12 kg of ion-exchanged water and stirring the system at room temperature.

[Preparation Example (P-2)] In a 20-liter enamel pot, 223.8 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) as a polymerization initiator and 12
and stirring the system at room temperature.
Aqueous solution of polymerization initiator (hereinafter referred to as “initiator solution (P-2)”
That. ) Was prepared.

<Preparation of Aqueous Solution of Sodium Chloride> 5.36 kg of sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) as a salting-out agent and 20.0 kg of ion-exchanged water were charged into a 35 liter stainless steel pot. This system was stirred at room temperature to prepare an aqueous solution of sodium chloride (hereinafter, referred to as "sodium chloride solution (N)").

<Preparation of resin fine particle dispersion> Temperature sensor,
4.0 kg of a surfactant solution (S-1) and a surfactant solution (S-1) were placed in a 100-liter internal capacity reactor equipped with a cooling pipe, a nitrogen introduction device, and a stirring blade, and having a glass lining treatment on the inner surface. S-2) 4.0 kg was charged, and 44.0 kg of ion-exchanged water was added while stirring the system at room temperature, and the system was heated. When the temperature of the system reached 70 ° C., 20.0 kg of an initiator solution (P-1) was added,
While controlling the temperature of the system to 72 ° C ± 1 ° C, styrene 1
2.1 kg, 2.88 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and t-dodecyl mercaptan
And a temperature of 80 ° C. ± 1 ° C.
Stirring was performed for 6 hours while controlling the temperature at ° C.

After cooling the system to a temperature of 40 ° C. or lower, 4.0 kg of the surfactant solution (S-1) was added to the system.
And 4.0 kg of a surfactant solution (S-2),
The system was heated. When the temperature of the system reached 70 ° C., 20.0 kg of an initiator solution (P-2) was added, and 11.0 kg of styrene and n-butyl acrylate were added.
A monomer mixture (II) consisting of 00 kg, 1.04 kg of methacrylic acid and 548 g of t-dodecylmercaptan was added, and the mixture was stirred for 6 hours while controlling the temperature of the system at 75 ° C ± 2 ° C. The temperature of this system is 80 ° C
Stirring was performed for 12 hours while controlling at ± 2 ° C.

The system was cooled until the temperature of the system became 40 ° C. or less, and the stirring was stopped. By removing the scale (foreign matter) by filtration with a pole filter, a dispersion liquid of composite resin fine particles having a high molecular weight resin component as a core and a low molecular weight resin component as a shell (hereinafter referred to as “latex (1)”). Prepared. The peak molecular weight of the high molecular weight resin component (core) of the composite resin fine particles constituting this latex (1) is 290,00
0, peak molecular weight of low molecular weight resin component (shell) is 12.0
The composite resin fine particles had a weight average particle size of 125 nm, a glass transition point of 58 ° C, and a softening point of 129 ° C.

<Salting out / fusion> Latex (1) 20. Was placed in a 100-liter stainless steel reaction vessel equipped with a temperature sensor, a cooling tube, a nitrogen introduction device, a comb baffle, and a stirring blade (anchor blade). 0 kg, 0.4 kg of the colorant dispersion (C), and 20.0 kg of ion-exchanged water were charged, and the system was stirred at room temperature. The temperature of the system was heated to 40 ° C., and 20 kg of sodium chloride solution (N), 6.00 kg of isopropyl alcohol (manufactured by Kanto Chemical Co.), and 1.0 kg of surfactant solution (S-3) were placed in this order. Was added. After leaving the system for 10 minutes, heating was started,
The mixture is heated to 85 ° C. over a period of 1 minute and stirred at 85 ° C. ± 2 ° C. for 1 hour, thereby salting out / fusing the composite resin fine particles and the colorant fine particles to contain a particulate solid. A slurry was obtained.

<Filtration / Washing and Drying Treatment> The obtained slurry was cooled until the temperature of the slurry became 40 ° C. or less, and the stirring was stopped. Thereafter, the slurry is put into a tank of a centrifuge in which a nonwoven filter cloth is set, and the centrifugal separator is operated under the condition of acceleration of 700 G to perform solid separation of the slurry. 1 kg of solid matter in the tank
Per liter of ion-exchanged water (conductivity 1.0 μS / cm), and the filtrate has a conductivity of 65 μS / cm, 55 μS / cm and 45 μS, respectively.
S / cm, 35 μS / cm, 25 μS / cm, 15 μS
/ Cm, at 5 μS / cm, the solid was sampled. Each sampled solid
The toner particles 1 to 7 were obtained by performing a drying treatment using a blow dryer at 0 ° C. until the water content became 0.5% by weight. Table 1 below shows the volume average particle diameter, the shape coefficient (average) of these toner particles 1 to 7, and the ratio (number%) of the toner particles having the shape coefficient of 1.5 to 2.0.

[0095]

[Table 1]

<Examples 1 to 5 and Comparative Examples 1 and 2> To each of the toner particles 1 to 7, hydrophobic silica (primary average particle diameter = 12 nm) was added at a ratio of 1% by weight. Then, five kinds of toners of the present invention and two kinds of comparative toners were obtained. The toner of the present invention (5)
And a comparative toner (two types) and a resin-coated carrier having a volume average particle diameter of 45 μm in which the surface of ferrite particles is coated with a styrene acrylic resin at a ratio of a toner concentration of 6%. As a result, a total of seven types of developers were prepared.

[Evaluation by Non-Contact Developing Method] For each of the above-mentioned developers, a fogging test was carried out under a high-temperature and high-humidity environment (temperature of 35 ° C., relative humidity of 85%) to form a copied image. The occurrence situation was evaluated. Specifically, an image having a pixel rate of 5% was continuously copied 100,000 times, and the fog density of the initial image and the image after 100,000 times were copied were measured. The density of fog was evaluated using a Macbeth reflection densitometer RD-918, and a relative density where the reflection density of paper was "0". As the fog density, the maximum fog density in white paper (A4) was adopted.

Here, as the image forming apparatus, a modified color copying machine “9028” manufactured by Konica Corporation (non-contact developing system) was used. A stacked organic photoreceptor was used as the photoreceptor, and a method of cleaning untransferred toner remaining on the photoreceptor surface with a blade was adopted. As the transfer paper, a paper having a continuous weight of 55 kg was used, and an image was formed in the vertical direction. As a fixing method, a heat roll fixing method was adopted. The developing conditions were set as follows. Table 2 shows the results of the evaluation.

Development conditions: photoconductor surface potential = -550 V, DC bias = -250 V, AC bias = Vp-p: -50 to -450 V, alternating electric field frequency = 1800 Hz, Dsd = 300 μm, pressing force = 10 gf / mm , Pressing control rod = SUS416 (Magnetic stainless steel) /
Diameter 3mm, developer layer thickness = 150μm, developing sleeve = 20mm

[Evaluation by Contact Developing Method] For each of the above-mentioned developers, fog was generated by performing an actual photographing test for forming a copied image under a high temperature and high humidity environment (temperature of 35 ° C., relative humidity of 85%). The situation was evaluated.
Specifically, an image having a pixel rate of 5% was continuously copied 100,000 times, and the fog density of the initial image and the image after 100,000 times were copied were measured. The density of fog was evaluated using a Macbeth reflection densitometer RD-918, and a relative density where the reflection density of paper was "0". As the fog density, the maximum fog density in white paper (A4) was adopted.

Here, as the image forming apparatus, a remodeled digital copier “7050” manufactured by Konica Corporation (contact development system) was used. A stacked organic photoreceptor was used as the photoreceptor, and a method of cleaning untransferred toner remaining on the photoreceptor surface with a blade was adopted. As the transfer paper, a paper having a continuous weight of 55 kg was used, and an image was formed in the vertical direction. As a fixing method, a heat roll fixing method was adopted. The developing conditions were set as follows. Table 2 shows the results of the evaluation.

Developing conditions: Photoreceptor surface potential = −700 V, DC bias = −500 V, Dsd = 600 μm, developer layer regulation = magnetic H-Cut system, developer layer thickness = 700 μm, developing sleeve diameter = 40 mmφ

[0103]

[Table 2]

As is clear from the results in Table 2, Example 1
According to the toners of (1) to (5), in both the non-contact development system and the contact development system, even when an image is continuously formed for a long time in a high-temperature and high-humidity environment, there is no fog and sharpness. An image can be obtained stably.

[0105]

According to the toner of the present invention, a sharp image can be stably obtained even when an image is continuously formed for a long time in a high temperature and high humidity environment. According to the method for producing a toner of the present invention, under a high-temperature and high-humidity environment, even when an image is continuously formed for a long time,
A toner capable of stably obtaining a sharp image can be manufactured.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Kono, Konica Corporation, 2970, Ishikawa-cho, Hachioji-shi, Tokyo (72) Inventor Naohiro Hirose 2970, Ishikawa-cho, Ishikawa-cho, Hachioji-shi, Tokyo (72) Inventor Company Naoyuki Nakamura Konica Corporation, 2970 Ishikawa-cho, Hachioji-shi, Tokyo (72) Inventor Hiroyuki Takaki Konica Corporation, 2970 Ishikawa-cho, Hachioji-shi, Tokyo F-term (reference) 2H005 AB03 AB09 EA01

Claims (3)

[Claims] 1. A filtrate having a conductivity of 50 μS / cm or less, while performing solid-liquid separation by centrifugation on a particulate solid obtained by salting out / fusing at least resin fine particles and colorant fine particles. A toner characterized by having toner particles obtained by washing the solid by supplying water until the solid is dried, and then drying the solid. 2. The filtrate has a conductivity of 50 μS / cm or less while performing solid-liquid separation by centrifugation on a particulate solid obtained by salting out / fusing at least resin fine particles and colorant fine particles. A method for producing a toner, comprising a step of washing the solid matter by supplying water until the solid matter is obtained, and then drying the solid matter to obtain toner particles. 3. An acceleration in centrifugation of 500 to 10
The method of claim 2, wherein the toner is 00G.