JPH0629989B2 - Method of manufacturing electrophotographic toner - Google Patents

Description

The present invention relates to a method for producing an electrophotographic toner using an emulsion polymerization method.

(Prior Art) In electrophotography, after uniformly charging the photoreceptor,
An optical image based on the original image is exposed to the photoconductor to eliminate or reduce charges in the light-irradiated portion to form an electrostatic latent image based on the original image on the photoconductor, and after that, development containing toner is performed. It is visualized by the agent. This visualized toner image is generally transferred to an appropriate transfer member and fixed to form a so-called copy.

The developer used in the above process is basically composed mainly of a colorant for developing the electrostatic latent image and a binder for fixing the image on the transfer body. Are roughly classified into so-called wet (liquid) developers and dry developers.

The dry developer can be further divided into a two-component developer and a one-component developer, the former consisting of a carrier and a toner, and the latter consisting of only a toner. In other words, it is a two-component type developer that obtains toner having a polarity opposite to that of the electrostatic charge image necessary for developing the electrostatic charge image on the photoconductor by frictional charging of the carrier and the toner. A one-component developer is one that is charged by friction between other members or friction with other members in the developing device.

Conventionally, such a toner for a dry developer is generally prepared by melting and kneading a coloring material such as carbon black and / or magnetic powder such as magnetite into a thermoplastic resin to form a dispersion, and then appropriately pulverizing it. It has been manufactured by a method in which an impact force is mechanically applied by an apparatus to pulverize the dispersion into a desired particle size and, if necessary, further classify it into a toner (hereinafter, this method is referred to as a pulverization method. ).

Such a method not only requires a great deal of energy for melt-kneading and pulverizing, but also the manufactured toner inevitably has many drawbacks. In particular, when a desirable resin is used in the melt-kneading process and the crushing process, for example, when a resin that easily melts is used, agglomeration (caking) during toner storage and fog due to toner filming on the photoconductor are caused. If a resin that is easily crushed is used, the toner is crushed into fine toner in the developing machine, causing image fog and stains inside the machine.

In addition, the colorant dispersed in the resin appears on the surface of the pulverized toner, which causes a decrease in the triboelectric charge amount in a high humidity state and a drop in the colorant in the developing machine.
This causes undesired phenomena such as carrier surface contamination and photoreceptor surface contamination.

In order to solve the drawbacks of such a crushing method, Japanese Patent Publication No.
No. 0799 proposes a method of producing completely spherical toner particles by spray-drying an emulsion obtained by an emulsion polymerization method.

Further, as a method for producing a toner using a polymerization method in order to solve the drawbacks of the pulverization method, there are methods of producing a toner by a suspension polymerization method such as Japanese Patent Publication No. 51-14895 and Japanese Patent Publication No. 57-53756. Proposed. When the suspension polymerization method is used, a spherical toner is obtained.

Conventionally, the toner obtained by using such a polymerization method is
Although some of the drawbacks of the toner obtained by the grinding method have been solved, it has been found that it causes new drawbacks. That is, the emulsifying agent or the suspending agent remains in the toner particles, so that the charging stability and the blocking property are deteriorated, and the toner particles obtained are spherical, so that the cleaning property is poor.

On the other hand, in the case of producing a toner by emulsion polymerization, it is possible to salt out the emulsion polymerization liquid and collect the particles, and pulverize the particles to an appropriate particle size. There is a drawback that the moisture resistance is significantly reduced.

Thus, until now, no sufficiently satisfactory toner has been obtained by the polymerization method.

(Object of the Invention) The present invention solves the above problems in the conventional toner manufacturing method, and is excellent in image density, resolution, and gradation, and particularly excellent in durability and moisture resistance, and cleaning. To provide a method for producing an electrophotographic toner capable of improving the property, the charging stability, and the blocking property, which is suitable for dry development, by using an emulsion polymerization method.

(Structure of the Invention) The present invention comprises emulsion-polymerizing a polymerizable monomer in the presence of a colorant and / or magnetic powder to produce a main resin component, and adding a salting-out agent to the obtained emulsion-polymerized liquid. , Salting out while heating to a temperature not lower than the glass transition temperature of the main resin component and not higher than 150 ° C., and / or heating particles obtained after salting out to a temperature not lower than the glass transition point of the main resin component and not higher than 150 ° C. The present invention relates to a method for producing a characteristic electrophotographic toner.

The emulsion polymerization of the polymerizable monomer in the present invention is carried out by emulsifying and polymerizing the polymerizable monomer in an aqueous medium containing an emulsifier.

During this emulsion polymerization, a colorant and / or magnetic powder and a polymerization initiator are allowed to be present. In addition, an offset preventing agent, a charge control agent, a fluidity improving agent, a toner property improving agent such as a cleaning property improving agent, a stabilizer for assisting emulsion dispersion, and a chain transfer agent can be appropriately present.

As a method of emulsifying and dispersing the polymerizable monomer in the aqueous medium, the polymerizable monomer, the emulsifier and the aqueous medium may be simultaneously stirred and mixed, and the polymerizable monomer is added to the aqueous medium in which the emulsifier is dissolved. However, the mixture may be mixed with stirring.

A polymerization initiator may be added after this emulsion dispersion,
It is preferable that the water-soluble polymerization initiator is previously dissolved in an aqueous medium at the time of emulsion dispersion. Further, as the polymerization initiator, an oil-soluble polymerization initiator can be used in combination, which is preferably dissolved in the polymerizable monomer in advance.

Further, in order to improve the dispersion in the resin, the colorant and / or the magnetic powder is preferably used after being dissolved or dispersed in the polymerizable monomer in advance, rather than being added after the emulsification and dispersion. The same applies to the toner property improver used as necessary. Further, the stabilizer may be used if necessary, but it may be added after the emulsification and dispersion, or may be dissolved in the aqueous medium in advance and used.

The stirring and mixing in the above emulsification and dispersion may be carried out at a relatively high speed using an ordinary stirrer, but it is preferable to carry out the stirring by high speed shearing using a homomixer or the like.
This is also the case when the colorant and / or the magnetic powder and the toner property improving agent used as necessary are dispersed in the polymerizable monomer.

Emulsion polymerization is performed after or while emulsifying and dispersing,
It is preferable to carry out at a temperature of 20 to 120 ° C., especially 5
It is preferably carried out at a temperature of 0 to 80 ° C.

The emulsion polymerization is preferably carried out until the polymerization rate becomes 99% by weight or more, and particularly preferably 99.9% by weight or more. If the polymerization rate is low and the amount of residual monomer is high, the toner properties, especially the storage stability, tend to be poor.

Further, the polymer obtained by emulsion polymerization preferably has a weight average molecular weight of 50,000 or more. If the molecular weight is too small, the cleaning property and anti-blocking property tend to deteriorate.

The obtained polymer has a glass transition point of 30 to 90 ° C.
Is preferable, and 50 to 80 ° C. is particularly preferable. If the glass transition point is too low, the blocking resistance tends to decrease, and if it is too high, the fixability tends to decrease. The glass transition point can be adjusted mainly by selecting the polymerizable monomer used.

By such emulsion polymerization, particles having a size of about 3 μm or less can be obtained.

Next, the materials used for emulsion polymerization will be described.

Examples of the polymerizable monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-
Ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn octyl styrene, pn-nonyl styrene, pn-decyl styrene , Pn-dodecylstyrene, n-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene and other styrenes and their derivatives, ethylene, propylene,
Ethylene unsaturated monoolefins such as butylene and isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide,
Vinyl halides such as vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl esters such as vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate,
Propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-chloromethyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl Propyl acid, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, acrylic Α-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl acidate and diethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, meta Crylamide, acrylic acid 2
Hydroxyethyl, 2-hydroxypropyl acrylate,
Acrylic acid or methacrylic acid derivatives such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and the like, and acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like can be used depending on the case. In addition, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone,
One or more kinds of vinyl ketones such as vinyl hexyl ketone and methyl isopropenyl ketone, N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone, and vinylnaphthalene salts. Can be used in combination. Among these polymerizable monomers, styrene or styrene derivative is
The amount of 0 to 100% by weight is very excellent in fixing property when the toner is copied onto paper by an electrophotographic copying machine.

Further, as the polymerizable monomer of the present invention, a compound having two or more polymerizable double bonds which serve as a crosslinking agent can be partially used. Aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and their derivatives, diethylene carboxylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol triacrylate, trimethylolpropane triacrylate, N, N All divinyl compounds such as divinylaniline, divinyl ether, divinyl sulphate, etc. and compounds having 3 or more vinyl groups can be used alone or as a mixture. The amount of the crosslinking agent used is 0 to 2 with respect to the total amount of polymerizable monomers.
0 wt% is preferable, and 0 to 5 wt% is particularly preferable.

Water is mainly used as the aqueous medium used in the emulsion polymerization. The ratio of the polymerizable monomer to the aqueous medium is preferably 40/60 to 90/10 in weight ratio of the former / the latter. If this ratio is too small, emulsion polymerization becomes difficult, and if it is too large, the yield decreases.

As the emulsifier, an anionic surfactant, a cationic surfactant, a zwitterionic surfactant and a nonionic surfactant can be used. Of these, when manufacturing negatively charged toner, an anionic surfactant is used,
When manufacturing a positively chargeable toner, it is preferable to use a cationic surfactant. In these cases, in order to improve the dispersion stability, it is preferable to use a nonionic surfactant together.

Examples of the anionic surfactant include fatty acid salts such as sodium oleate and potassium castor oil, alkyl sulfates such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalenesulfonates. , Dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin condensate,
There are polyoxyethylene alkyl sulfate ester salts and the like.

Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin, fatty acid ester, oxyethylene. -Oxypropylene block polymer and the like.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride and stearyltrimethylammonium chloride.

Examples of zwitterionic surfactants include lauryl trimethyl ammonium chloride.

The amount of the emulsifier used is preferably 0.01 to 10% by weight, more preferably 0.5 to 5% by weight, based on the polymerizable monomer. If the amount of the emulsifier used is too small, stable emulsion polymerization becomes difficult, and if it is too large, the moisture resistance of the toner obtained is poor.

Stabilizers include polyvinyl alcohol, starch,
There are water-soluble polymers such as methyl cellulose, carboxymethyl cellulose and hydroxyethyl cellulose, and these are preferably used in an amount of 0 to 1% by weight based on the polymerizable monomer.

Examples of the water-soluble polymerization initiator usable in the present invention include, for example,
Persulfates such as potassium persulfate and ammonium persulfate,
Hydrogen peroxide, 4,4'-azobis cyanovaleric acid
De, 2,2'-azobis (2-amidinopropane) dihydrochloric acid
Salt, t-butyl hydroperoxide, cumene-high
Dropper oxide and the like can be used. Especially for persulfate
If present, the sulphate anion that becomes the starting active site
Radical (SO ) Is present on the surface of the monomer,
Particles are stabilized by the hydrophilicity and charging of the group
It is easy to obtain an emulsion having a uniform particle size. Usage is heavy
0.01 to 10% by weight is preferable with respect to the compatible monomer.
0.1 to 5% by weight is preferable. Too little polymerization initiator
And the polymerizable monomer is not completely polymerized and remains in the toner.
Worsen the characteristics of.

As the polymerization initiator, benzoyl peroxide, t-
Peroxides such as butyl perbenzoate and oil-soluble polymerization initiators such as azo compounds such as azobisisobutyronitrile and azobisisobutyvaleronitrile can be used in combination. The oil-soluble polymerization initiator is preferably used in 100% by weight or less based on the water-soluble polymerization initiator.

The water-soluble polymerization initiator may be used in combination with a reducing agent. As the reducing agent, there are commonly known reducing agents such as sodium metabisulfite and ferrous chloride. The reducing agent does not necessarily have to be used, but when used, it is preferably used in an equivalent amount or less with respect to the water-soluble polymerization initiator.

Chain transfer agents include alkyl mercaptans such as t-dodecyl mercaptan, lower alkyl xanthogens such as diisopropyl xanthogen, carbon tetrachloride, carbon tetrabromide, etc., and are used in an amount of 0 to 2% by weight based on the polymerizable monomer. Preferably.

Examples of the colorant preferably used in the present invention include pigments and dyes. For example, various carbon blacks, nigrosine dyes (CI No. 50415), aniline blue (CI No. 50405), and chalco oil blue (CI No. azoec Blue). 3), Chrome Yellow (CIN
o.14090), Ultramarine Blue (CI No.77
103), Dyupon Oil Red (CI No. 2610
5), Orient Oil Red # 330 (CI No.60
505), quinoline yellow (CI No. 47005),
Methylene Blue Chloride (CI No. 52015), Phthalocyanine Blue (CI No. 74160), Malachite Green Oxalate (CI No. 42000), Rambu Black (CI No. 77266), Rose Bengal (CI No. 45435), Oil Black, Azo Oil Black etc. These can be used alone or in combination. These colorants may be used in any amount, but for the purpose of obtaining the required concentration and for economic reasons, they are contained in the toner in an amount of about 1 to 30% by weight, preferably 5 to 15% by weight.
It is used in a proportion such that it will be weight percent.

As the pigment or dye, those subjected to various treatments for the purpose of increasing the dispersibility in the polymerization reaction system or the toner of the present invention may be used. Examples of the treatment include treatment with a nigrosine dye (CI No. 50415) using an organic acid such as stearic acid and maleic acid.

Among these colorants, various carbon blacks, such as fannes black, channel black, thermal black, acetylene black and lamp black, are particularly preferable for the toner of the present invention. Further, the carbon black may be surface-treated. The surface treatment includes, for example, oxidation treatment using various oxidizing agents such as oxygen, ozone and nitric acid, and surface adsorption treatment with an organic acid ester such as dibutyl phthalate and dioctyl phthalate.

When using carbon black as the colorant, it is preferable to use grafted carbon black. The grafted carbon black is obtained by polymerizing the above polymerizable monomer by a method such as bulk polymerization or solution polymerization in the presence of carbon black. The polymer component of the grafted carbon black is preferably 50% by weight or less, more preferably 30% by weight or less based on the grafted carbon black. The grafted carbon black is
In emulsion polymerization, the dispersion stability is excellent, which is preferable, but when the amount of the polymer component is too large, the viscosity tends to be too high when dispersed in the polymerizable monomer, and the workability is deteriorated. The amount of the grafted carbon black used is preferably determined by the amount of carbon black component.

Magnetic powder is used in the production of magnetic toner, which can also serve as a colorant. Preferred magnetic powders include, for example, iron such as magnetite or ferrite, or oxides or compounds of elements exhibiting ferromagnetism such as nickel and cobalt. These magnetic powders have a particle size of 0.
A powder of 01 to 3 μm is preferable, and the surface of the magnetic powder may be treated with a resin, a titanium coupling agent, a silane coupling agent, a higher fatty acid metal salt or the like. These magnetic substances may be contained in the toner in an amount of 20 to 80% by weight, preferably 35 to 70% by weight. Less than this amount may be used as a colorant.

Anti-offset agents are used as needed. The anti-offset agent can be present in the system in various forms during polymerization and incorporated into the toner as a product. Alternatively, it may be added later to the toner of the present invention in which no offset inhibitor is present. As the anti-offset agent,
Various natural waxes, such as carnauba wax, hydrogenated castor oil, low molecular weight olefin polymers, etc. are used in the present invention, but preferably low molecular weight olefin polymerisability is used. As the low molecular weight olefin polymer, a low molecular weight olefin polymer or a copolymer of olefin and a monomer other than olefin is used. here,
As olefin, ethylene, propylene, butene-1
As a monomer other than olefin, there are acrylic acid ester, methacrylic acid ester, and the like. As this low molecular weight olefin polymer, for example, JP-A-55 is used.
Polyalkylenes described in JP-A-153944 and low molecular weight olefin copolymers described in JP-A No. 50-93647 can be used.

The molecular weight of the low molecular weight olefin polymer of the present invention may be one that is included in the concept of low molecular weight usually referred to as a high molecular weight compound, but generally it is 1,000 to 45 in terms of weight average molecular weight (Mw),
000, preferably 2,000 to 6,000.

The low molecular weight polyolefin polymer of the present invention has a softening point of 10
Those having a temperature of 0 to 180 ° C., particularly 130 to 160 ° C. are preferable.

The amount of the low molecular weight olefin polymer that can be used in the present invention is not particularly limited, but it is preferably in the range of 0 to 30% by weight based on the weight of the toner, and more preferably 1 to 3%.
0% by weight is used. If the amount of the low molecular weight olefin polymer is too small, the offset effect due to the addition of the low molecular weight olefin polymer does not appear, and if it exceeds 30% by weight, gelation may occur during the polymerization reaction.

Furthermore, a fluidity improver, a cleaning property improver, etc. can be used if necessary. These can be present in the product toner by allowing them to be present in the polymerization reaction system, but are preferably externally added to the product toner afterwards. The content of these is preferably 0% by weight to 3% by weight with respect to the toner of the present invention. As the fluidity improver, silane,
There are titanium, aluminum, calcium, magnesium and magnesium oxides or the above oxides that have been hydrophobized with a titanium coupling agent or a silane coupling agent, and cleaning property improvers include zinc stearate, thirium stearate and There are metal salts of higher fatty acids such as magnesium laurate or aromatic acid esters such as pentaerythritol benzoate.

In the present invention, the so-called charge amount and charge polarity of the product toner can be freely adjusted by selecting the polymerizable monomer and the colorant, but in order to adjust the charge amount and charge polarity to more desired values, A so-called charge control agent may be used in combination with the colorant in the toner of the invention.

The charge control agent preferably used in the present invention includes, for example, Spyron Black TRH and Spyron Black TPH.
(Hodogaya Kagaku) and other azo dyes such as p-fluorobenzoic acid, p-nitrobenzoic acid, and aromatic acid derivatives such as 2,4-di-t-butylsalicylic acid such as dibutyl-tin oxide and dioctyl-tin oxide. Examples thereof include tin compounds. These are preferably used in an amount of 0 to 5% by weight based on the polymerizable monomer.

In the present invention, after the main resin component is produced by emulsion polymerization, a salting-out agent is added to the obtained emulsion polymerization liquid for salting out. In the present invention, the salting-out is carried out while heating the salting-out to a temperature not lower than the glass transition point of the main resin component and not higher than 150 ° C., and / or particles obtained after the salting-out are subjected to the glass transition of the main resin component. It is necessary to heat to a temperature not lower than the point and not higher than 150 ° C. (hereinafter referred to as “heat treatment”).

This heat treatment increases the bulk density of the particles and improves the moisture resistance and durability. Especially, the durability is most improved.

The heat treatment temperature is 150 ° C. as the upper limit. If this temperature is too high, not only the main resin components are easily deteriorated, but also the heating equipment becomes complicated.

The heat treatment temperature is 25 than the glass transition point of the main resin component.
Most preferred is a temperature of ~ 60 ° C higher.

The salting-out can be carried out by a method of mixing the emulsion polymerization liquid and the salting-out agent aqueous solution at a constant ratio, a method of gradually dropping the emulsion polymerization liquid into the salting-out agent aqueous solution with stirring, and the like. Can be performed by heating the mixture produced in the above operation.

When heat treating after salting out, the temperature during salting out is not particularly limited. This heat treatment may be carried out by continuously heating the salting-out solution after salting out, and after separating the particles, if necessary, a washing step or a crushing step is inserted and dispersed in an aqueous medium and heated. You can go. In some cases, the heat treatment during salting out and the heat treatment after salting out may be used together.

In the salting out, the particle size component of the obtained particles is 1 to 10
It is preferable to adjust to 0 μm, especially 3 to 7
It is preferably adjusted to 0 μm, and most preferably adjusted so that particles of 5 to 25 μm are the main component. The average particle size is preferably adjusted to 9 to 15 μm. For this purpose, it is preferable to use the salting-out agent in an amount of 0.1 to 5 times the weight of the emulsifier in the emulsion polymerization liquid, and
It is preferable to use 0.3 to 3 times. As a result, the obtained particles can be used as a toner as they are or by simply classifying them, so that the pulverizing step is not necessary, and therefore the drawbacks of the pulverizing toner can be solved. In addition, salting out produces incompletely spherical toner particles, resulting in toner particles having excellent cleaning properties.

In the salting out, large particles of 100 μm or more may be generated, and in this case, a pulverization step is necessary to obtain a particle size suitable for toner particles. Even in this case, since the heat treatment is performed in the present invention, the bulk density of the particles is increased, and accordingly, the moisture resistance and the durability can be improved. Further, the colorant and / or the magnetic powder and the toner property improving agent used as required solves the drawbacks of the pulverized toner, such as good dispersion in the resin and slight pulverization. be able to.

Examples of the salting-out agent include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as formic acid and oxalic acid, these acids and alkaline earth metals,
There are water-soluble metal salts such as aluminum. These salting-out agents can be used alone or in combination, but preferred salting-out agents are magnesium sulfate, aluminum sulfate, barium chloride, magnesium chloride, calcium chloride, sodium chloride and / or a combination thereof with an inorganic acid. . These salting-out agents are preferably used as 0.1 to 10% by weight aqueous solution, particularly 0.1 to 5% by weight aqueous solution.

The liquid obtained through the salting-out step (and heat treatment step) is in the form of a slurry, which can be spin-dried to isolate the particles, which can be further washed and dried, and in some cases After that, it is classified as electrophotographic toner.

Here, in particular, the washing further removes the emulsifier attached to the toner, and can contribute to the improvement of the charging stability and the blocking property of the toner obtained in the salting-out step.

The washing is preferably performed with warm water of 40 to 70 ° C,
It may be lower than 40 ° C.

The toners obtained according to the present invention are described in various developing processes such as the cascade developing method described in US Pat. No. 2,618,552, the magnetic brush method described in US Pat. No. 2,874,065, and US Pat. No. 2,221,776. A powder cloud method, a touchdown developing method described in U.S. Pat. No. 3,166,432, a so-called jumping method described in Japanese Patent Laid-Open No. 55-18656, and a so-called magnetic toner manufactured by a crushing method as a carrier. It can be used for a microtoning method, a so-called bipolar magnetic toner method for obtaining a necessary toner charge by frictional charging between magnetic toners, and the like.

Further, the toner obtained by the present invention can be applied to various fixing methods,
For example, it can be used in so-called oilless and oil coating heat roll method, flash method, oven method, pressure fixing method and the like.

Further, the toner of the present invention is used in various cleaning methods,
For example, it can be used for so-called a fur brush method, a blade method and the like.

(Example) Next, the Example of this invention is shown. Hereinafter,% means% by weight.

Example 1 (1) Production of emulsion polymerization liquid 100 g of grafted carbon (grafted carbon GP-E-2 manufactured by Ryoyu Kogyo Co., Ltd.) on the stainless beaker of 3.
Further, 400 g of styrene as a polymerization monomer, 120 g of butyl acrylate, and 0.6 g of t-dodecyl mercaptan as a chain transfer agent were added to the homomixer at 3000 rpm at 30 rpm.
Mix and disperse for minutes.

Next, add 1300g of ion-exchanged water to this carbon dispersion.
As an emulsifier, 12 g of anionic surfactant sodium dodecylbenzenesulfonate, and nonionic surfactant Nonipol PE-68 (Sanyo Chemical Co., Ltd. oxypropylene-oxyethylene block polymer) 3
g, Neugen EA170 (Daiichi Kogyo Seiyaku Co., Ltd. polyoxyethylene glycol nonyl phenyl ether) 3 g
An aqueous solution in which 12 g of ammonium persulfate was dissolved was added as a polymerization initiator, and the mixture was emulsified with a homomixer for another 30 minutes to obtain a black pre-emulsion.

Then, the black pre-emulsion was transferred to a 34-neck separable flask equipped with a stirrer, nitrogen inlet, thermometer, and condenser.
After polymerization for a period of time, it was cooled to obtain an emulsion polymerization liquid. The polymerization rate at this time was 99.5% or more. The molecular weight of the polymer was measured by gel chromatography using a standard polystyrene calibration curve, and the weight average molecular weight (M
w) It was 86,000 and the number average molecular weight (Mn) was 30,000.

(2) Salting-out step / final step The emulsion polymerization solution 1 was added dropwise to the 0.3% aqueous MgSO ₄ solution 2 heated to 100 ° C. with sufficient stirring while keeping the temperature of the aqueous solution at 100 ° C., uniformly over about 30 minutes. Salted out. The temperature was kept at this temperature for another 30 minutes and cooled to room temperature. Then, this slurry was dehydrated with a centrifugal dehydrator, and then washed repeatedly with hot water at 50 ° C. three times. Then, it was dried at 30 to 35 ° C. in a dryer to obtain a toner. When the particle diameter of the obtained toner was measured with a Coulter counter, the particle diameter was 3 to 80 μm and the average particle diameter was 18 μm. Further, the glass transition point (Tg) was measured by a differential scanning calorimeter and found to be 73 ° C. When this toner was further classified to 5 to 25 μm by a zigzag classifier (100MZR, manufactured by Alpin Co.), the yield was 90% compared to before classification. Also in the following Examples and Comparative Examples, the particle diameter and the average particle diameter were measured with a Coulter counter, the glass transition point was measured with a differential scanning calorimeter, and the classification was performed with a zigzag classifier.

Examples 2 to 4 and Comparative Examples 1 to 2 The emulsion polymerization liquid 1 obtained in Example 1 was immersed in an aqueous salting-out agent solution (shown in Table 1) heated to the salting-out temperature shown in Table 1 for about 30 minutes. Was evenly dropped and salted out. During the salting-out, the salting-out temperature was maintained, and after the addition of the emulsion polymerization solution was completed, the temperature was kept at the same temperature as the salting-out temperature for 30 minutes and then cooled to room temperature. The salting-out liquid (slurry) thus obtained was dehydrated with a centrifugal dehydrator and then washed three times with warm water at 50 ° C. Then 30 ~ 3
It was dried in a dryer at 5 ° C. to obtain toner particles. The particle diameter of the toner particles, the average particle diameter, the yield of particles having a particle size of 5 to 25 μm, and the glass transition point of the main resin component are shown in Table 1 together with the results of Example 1.

Using the classified toners obtained in Examples 1 to 4 and Comparative Examples 1 to 2, a plain paper copying machine (u-Bix1600, manufactured by Konishi Roku Photo Industry Co., Ltd.) using a commercially available insulating carrier was used. The electrophotographic toner properties were tested. However, to each toner, hydrophobic silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) and zinc stearate as external additives were added to the toner by 0.6% and 0.1%, respectively. The test results are shown in Table 1.

Examples 5 to 7 The emulsion polymerization liquid 1 obtained in Example 1 and the salting-out agent aqueous solution (shown in Table 2) heated to the salting-out temperature shown in Table 2 were used, and the same as in Examples 1 to 4 Salted out. The salting-out liquid (slurry) thus obtained was transferred to an autoclave and heated at the heat treatment temperature shown in Table 2 for 30 minutes. After this, it is cooled and the first embodiment
Toner was obtained by dehydration, washing with water, and drying in the same manner as in Nos. 4 to 4.

Table 2 shows the particle size of the obtained toner, the average particle size, the yield of particles of 5 to 25 μm, and the electrophotographic characteristics tested in the same manner as in Examples 1 to 4.

Example 8 (1) Process for producing emulsion polymerization liquid 100 g of grafted carbon, 360 g of styrene, 180 g of butyl methacrylate, 6 g of methacrylic acid, 0.6 g of t-dodecyl mercaptan and low molecular weight polypropylene (Viscor 550P, Sanyo Kasei Co., Ltd. product) Name) 6
g was mixed and dispersed in a homomixer at 3000 rpm for 30 minutes.

Then, 1500 g of ion-exchanged water, 18 g of sodium dodecylbenzene sulfonate, 4 g of nonionic surfactant nonipol PE-68 (trade name of Sanyo Chemical Industry Co., Ltd.),
An aqueous solution prepared by dissolving 4 g of nonionic surfactant Neugen EA170 (trade name of Daiichi Kogyo Seiyaku Co., Ltd.), 9 g of ammonium persulfate and 3 g of hydrogen peroxide was added to a homomixer,
Emulsified at room temperature at 3000 rpm for 30 minutes to obtain a black pre-emulsion.

This black pre-emulsion was transferred to a three-four-necked separable flask, polymerized under a nitrogen stream at 70 ° C. for 5 hours, and then cooled to obtain an emulsion polymerization solution.

The polymerization rate at this time was 99.5% or more, and the molecular weight of the polymer obtained in the same manner as in Example 1 was 105,000 for Mw and 41,000 for Mn.
It was.

(2) Salting Out Step / Final Step Toner particles were obtained in the same manner as in Examples 1 to 4 by using the salting out agent aqueous solution and the salting out temperature shown in Table 3.

Example 9 Emulsion polymerization liquid 1 obtained in Example 1, aqueous salting-out agent solution shown in Table 3, salting-out temperature and heat treatment temperature were used to give Examples 5-7.
The salting out step and the final step were performed in the same manner as in 1. to obtain a toner.

The toner particles obtained in Examples 8 and 9 had an average particle size of 5,
Table 3 shows the yield of particles of .about.25 .mu.m, the glass transition point of the main resin component, and the electrophotographic characteristics tested in the same manner as in Examples 1 to 4.

Example 10 (1) Emulsion polymerization liquid production process In Example 8, 30 g of carbon black (Carbon Black # 44, Mitsubishi Kasei Kogyo Co., Ltd. trade name, Fanes Black carbon black) was used in place of 100 g of grafted carbon. I used styrene of 414g,
An emulsion polymerization liquid was obtained in the same manner as in Example 8 except that low molecular weight polypropylene and hydrogen peroxide were not used.

The polymerization rate at this time is 99% or more, the Mw of the polymer is 90,000,
The Mn was 29,000.

(2) Salting-Out Step / Final Step The toner was obtained in the same manner as in Examples 1 to 6 except that the emulsion polymerization solution 1, the aqueous salting-out agent solution shown in Table 4 and the salting-out temperature were used.

Examples 11 and 12 Emulsion polymerization liquid 1 obtained in Example 10, aqueous salting-out solution shown in Table 4, salting-out temperature and heat treatment temperature were used to give Examples 5-7.
A toner was obtained in the same manner as in.

The toner particle size, the average molecular weight, the yield of particles of 5 to 25 μm, the glass transition point of the main resin components, and the electrophotographic characteristics measured in the same manner as in Examples 1 to 4 are shown in Tables 1. 4 shows.

Example 13 The emulsion polymerization liquid 1 obtained in Example 8 was used as a 6% MgSO ₄ aqueous solution 1
While stirring, the mixture was added dropwise at room temperature for salting out. At this time, the weight ratio of emulsifier / salting-out agent was 1 / 6.6. Polyvinyl alcohol 1% aqueous solution 10 g as a stabilizer in the salted-out liquid
Was added and heat-treated at 100 ° C. for 30 minutes. Then it was cooled to room temperature. At this time, the particle size of the particles in the salting-out solution is 100-
It was 500 μm. After this, dehydration with a centrifugal dehydrator, 5
It was washed three times with warm water of 0 ° C. and dried at 40 ° C. in a dryer. The obtained particles were pulverized by a jet mill so that the average particle size was 10 μm, and further classified by a classifier to 5 to 25 μm.

The glass transition temperature of the main resin component of the obtained toner is 76 ° C.
It was. Further, as a result of testing the electrophotographic characteristics in the same manner as in Examples 1 to 4, the resolution (line / inch) was 4.0, the image density was 1.1, the gradation was 6, the moisture resistance was 1.5 (%), and the durability was ○. .

Comparative Example 3 (Production of Toner by Suspension Polymerization) 70 g of styrene, 30 g of butyl methacrylate, 15 g of grafted carbon and 2 g of benzoyl peroxide were sufficiently kneaded with a homomixer, and 500 g of a 1% aqueous solution of 3 calcium phosphate was added to the homomixer. Further 3000 r.p.
Dispersed at m for 30 minutes.

This dispersion was transferred to a flask and suspension-polymerized at 80 ° C. for 7 hours. The polymerization rate was 99% or more. This polymer was dehydrated, washed with an aqueous hydrochloric acid solution having a pH of 2 or less, and then dried to obtain a toner. The resin of this toner had Mw of 110,000 and Mn of 50,000.

Comparative Example 4 (Production of Toner by Emulsion Polymerization and Spray Drying) The emulsion polymerization liquid obtained in Example 1 was spray dried at a temperature of 110 ° C. to obtain a toner.

Comparative Example 5 (Pulverizing method) Styrene / butyl methacrylate = 70/30 (weight ratio) by solution polymerization using toluene as a solvent, molecular weight Mw 70,000 and
A polymer of Mn 30,000 was prepared, and the solvent was removed under reduced pressure to remove toluene to form a white solid. To 1,000 g of this polymer, 50 g of carbon black, 10 g of phthalocyanine copper, and 20 g of low molecular weight polypropylene (Viscor 550P, trade name of Sanyo Kasei Co., Ltd.) were kneaded with a two-roll mill and pulverized with a jet mill to obtain a toner.

Comparative Example 6 The procedure of Example 13 was repeated, except that 10 g of a 1% aqueous solution of polyvinyl alcohol was added and the heat treatment at 100 ° C. for 30 minutes was omitted.

The toner particles obtained in Comparative Examples 3 to 6 had a particle size, an average particle size of 5,
Table 5 shows yields of particles of -25 μm, glass transition points of main resin components, and electrophotographic characteristics tested in the same manner as in Examples 1 to 4.
Shown in.

The electrophotographic characteristics in Examples 1 to 14 and Comparative Examples 1 to 6 were evaluated as follows.

(a) Resolution: Electrophotographic Society Test Chart No. 1 was used to make a copy on plain paper using each developer.
The copied image was evaluated by comparing whether the image could be read in detail.

(b) Image density: The density of the black portion of the copied paper was measured with a densitometer and judged in the same manner as the resolution.

(c) Gradation: As in the case of resolution, evaluation was performed using the shaded area divided into 11 stages in the central portion of the test chart.

(d) Cleanability: Each of the prepared developers was subjected to continuous copying under the conditions of a temperature of 30 ° C. and a humidity of 80% RH using a copying machine, and evaluated by the number of copies until a cleaning failure occurred.

(e) Blotting property: The toner prepared in Examples 1 to 14 and Comparative Examples 1 to 3 was allowed to stand for 72 hours at 50 ° C. and 95% humidity to determine whether the toner was blocked. ⊚: Very excellent Yes: Excellent Δ: Somewhat inferior ×: Inferior

(f) Charge stability: Each developer is stirred by a copying machine and the charge amount is measured at regular intervals to judge by the change in charge amount. ◎: Very good ○: Excellent △: Slightly inferior X: evaluated as inferior.

(g) Durability: 10,000 copies of each of the prepared developers were continuously copied under the conditions of a temperature of 30 ° C. and a humidity of 80% RH using a copying machine. The scattering of the toner generated at this time was examined and evaluated according to the following evaluation.

A: There is no toner scattering.

◯: Some scattering of toner is seen.

Δ: A large amount of toner is scattered.

X: A large amount of toner is scattered.

(h) Moisture resistance: Each of the toners prepared is kept at 25 ° C and a humidity of 98
The sample is allowed to stand for 24 hours under the condition of%, and the ratio of the weight increase after humidification to the weight before humidification is shown in%.

Using the toners obtained in Examples 1 to 14 and Comparative Examples 3 to 6, a plain paper copying machine using a conductive carrier (Copier N
Table 6 shows the results of a test for resolution, image density and gradation that were carried out using C-3000) in the same manner as the electrophotographic characteristic test.

(Effects of the Invention) By the method for producing an electrophotographic toner according to the present invention, a toner excellent in resolution, image density and gradation, and particularly excellent in durability and moisture resistance can be obtained by using an emulsion polymerization method. . Further, in addition to the above characteristics, it is possible to obtain a toner excellent in cleaning property, charging stability and blocking property.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuyuki Iguchi 4-13-1, Higashimachi, Hitachi City, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Yamazaki Plant (72) Inventor Kenichi Kurumi 4-13, Higashimachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi Chemical Co., Ltd. Yamazaki Plant (72) Inventor Shigeki Tanaka 4-13-1 Higashimachi, Hitachi City, Ibaraki Hitachi Chemical Co., Ltd. Yamazaki Plant (72) Inventor Takashi Amano Hitachi City, Ibaraki Prefecture 4-13-1 Higashimachi, Hitachi Chemical Co., Ltd. Yamazaki Factory (56) Reference JP-A-58-50545 (JP, A) JP-A-58-37651 (JP, A) JP-A-56-98202 ( JP, A) JP 53-6040 (JP, A) JP 56-70556 (JP, A)

Claims (2)

[Claims] 1. A main resin component is produced by emulsion-polymerizing a polymerizable monomer in the presence of a colorant and / or magnetic powder, and a salting-out agent is added to the obtained emulsion-polymerized liquid to obtain a main resin component. Electron characterized by salting out while heating to a temperature not lower than the glass transition temperature of 150 ° C. and / or heating particles obtained after salting out to a temperature not lower than the glass transition point of the main resin component and not higher than 150 ° C. Manufacturing method of photographic toner. 2. The method for producing an electrophotographic toner according to claim 1, wherein at least one compound selected from inorganic acids, organic acids and water-soluble metal salts thereof is used as a salting-out agent.