JPS60220358A - Production of toner for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a process for producing a toner having excellent cleaning property electrification stability and blocking property by subjecting a polymerizable monomer to emulsion polymn. in the presence of a coloring material and/or magnetic powder to produce a main resin component and subjecting the same to salting out so that the particles in the emulsified polymer liquid have the grain size suitable for the toner. CONSTITUTION:The polymerizable monomer is emulsified and dispersed in an aq. medium contg. an emulsifier and is polymerized in the emulsion polymn. of the polymerizable monomer. The coloring agent and/or magnetic powder as well as a polymn. initiator are made present in the stage of such emulsion polymn. The polymn. is progressed until the degree of polymn. attains >=99wt% and the polymer having >=50,000wt. average mol.wt. is more preferable. The particles sized to about <=3mum are obtd. by the emulsion polymn. A salting out agent is added to the resultant emulsion polymer liquid to floccuate adequately the particles by salting out, by which the imperfectly spherical resin particles having the larger average grain size than the average grain size of the particles in the emulsion polymer liquid and suitable for the toner without requiring pulverizing are obtd. More specifically, the particles are adjusted to 9-15mum average grain size.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing an electrophotographic toner using an emulsion polymerization method.

(Prior art) In electrophotography, after uniformly charging a photoreceptor,
The photoreceptor is exposed to a light image based on the original image, and the charge on the light-irradiated area is eliminated or reduced.

Forms an electrostatic latent image on the photoreceptor based on the original image.

Thereafter, it is visualized using a developer containing toner. This visualized toner image is generally transferred to a suitable transfer member and fixed thereon to form a so-called copy.

The developer used in the above process basically consists of a coloring agent to visualize the electrostatic latent image and a binder to fix the developed image to the transfer material. They are broadly classified into so-called wet (liquid) developers and dry developers.

Dry developers can be further divided into two-component developers and one-component developers, with the former consisting of a carrier and toner, and the latter consisting only of toner. In other words, a two-component developer is one that obtains a toner of opposite polarity to the electrostatic charge image required to develop the electrostatic charge image on the photoconductor by triboelectrically charging the carrier and toner. A one-component developer is one that is charged by friction between toner particles or friction with other members in a developing device.

Conventionally, toner for such a dry developer is generally made by melting and kneading a colorant such as carbon black and/or a magnetic powder such as magnetite into a thermoplastic resin to form a dispersion. Toners have been produced by mechanically applying impact force to crush the dispersion to a desired particle size, and if necessary, further classifying it to form a toner.
below.

This method is called the crushing method).

Such a method is not foolproof as it requires a large amount of energy for melting and pulverizing.

The produced toner necessarily has a number of drawbacks.

In particular, when a desirable resin is used in the melt mixing process and the crushing process, 9 For example, when a resin that is easily melted is used, problems such as agglomeration (caking) during toner storage and capri caused by toner filming on the photoconductor may occur. invite the
Furthermore, if a resin that is easily crushed is used, it will be crushed in the developing device, resulting in fine toner particles, resulting in image capri and dirt inside the machine.

In addition, the colorant dispersed in the resin appears on the surface of the pulverized toner, resulting in a decrease in the amount of triboelectric charge in high humidity conditions and the colorant falling off in the developing machine.
This causes undesirable phenomena such as contamination of the carrier surface and contamination of the photoreceptor surface.

In order to solve the drawbacks of this pulverization method, 9% Kosho 43-1
．． Japanese Patent No. 0799 proposes a method for producing completely spherical toner particles by spray drying an emulsion obtained by emulsion polymerization.

In addition, as a toner manufacturing method using a polymerization method in order to solve the drawbacks of the pulverization method, a toner manufacturing method using a suspension polymerization method is described in Japanese Patent Publication No. 14895/1989, Japanese Patent Application Laid-Open No. 57-53756, etc. Proposed. When using the suspension polymerization method, a perfectly spherical toner can be obtained.

Conventionally, toners obtained using such polymerization methods are
Although some of the drawbacks of toners obtained by the grinding method have been overcome, it has been found that new drawbacks are introduced. That is, since the obtained toner particles are perfectly spherical, the cleaning properties are poor.

Furthermore, since the emulsifier or suspending agent remains in the toner particles, charging stability and blocking properties are reduced.

(Object of the Invention) The present invention solves these problems in the conventional toner manufacturing method, and is aimed at reducing the density of one image.

An electrophotographic toner suitable for dry development that has excellent resolution, nine gradations, and especially excellent cleaning properties, charging stability, and blocking properties is manufactured using an emulsion polymerization method, and does not require a pulverization process. A method for producing toner is provided.

(Structure of the Invention) The present invention involves producing a main resin component by emulsion polymerizing nine polymerizable monomers in the presence of a colorant and/or magnetic powder, and adding the obtained emulsion polymerization solution to the emulsion polymerization solution. The present invention relates to a method for producing an electrophotographic toner, which comprises salting out the particles so that they have a particle size suitable for the toner.

The emulsion polymerization of the polymerizable monomer in the present invention is carried out by emulsifying and dispersing the 9-polymerizable monomer in an aqueous medium containing an emulsifier and polymerizing the emulsion polymerization.

During this emulsion polymerization, two colorants and/or magnetic powder and a polymerization initiator are present. others.

Anti-offset agent, charge control agent, fluidity improver.

A toner property improving agent such as a cleaning performance improving agent, a stabilizer for assisting emulsification and dispersion, and a chain transfer agent may be appropriately present.

As a method for emulsifying and dispersing the polymerizable monomer in an aqueous medium, the polymerizable monomer, the emulsifier, and the aqueous medium may be stirred and mixed simultaneously, or the polymerizable monomer is added to the aqueous medium in which the emulsifier is dissolved. However, they may be mixed by stirring.

The polymerization initiator may be added after this emulsification and dispersion, but
It is preferable to dissolve the water-soluble polymerization initiator in advance in an aqueous medium during emulsification and dispersion. Further, as the 9-polymerization initiator, an oil-soluble polymerization initiator can be used in combination, and it is preferable to dissolve this in advance in the 9-polymerizable monomer.

In order to improve dispersion in the resin, the colorant and/or 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 if necessary. Furthermore, stabilizers may be used as needed, but only if necessary.

It may be added after the emulsification and dispersion, or it may be used after being dissolved in an aqueous medium in advance.

Stirring and mixing in the above emulsification dispersion may be carried out by stirring at a relatively high speed using an ordinary stirrer, but it is preferably carried out by stirring by high-speed shearing using a homomixer or the like.

This also applies to the case where a colorant and/or magnetic powder and an optional toner property improver are dispersed in the 9-polymerizable monomer.

Emulsion polymerization is carried out after or during emulsion dispersion,
It is preferable to carry out at a temperature of 20 to 120°C, especially at a temperature of 5.
Preferably, it is carried out at a temperature of 0 to 80°C.

This emulsion polymerization is preferably carried out until the polymerization rate reaches 99% by weight or more, particularly preferably 999% by weight or more. When the polymerization rate is low and the amount of residual monomer is large, toner properties, especially 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 (p), cleaning properties and blocking resistance tend to deteriorate.

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

Such emulsion polymerization results in particles of about 3 μm or less.

Next, materials used for emulsion polymerization will be explained.

Examples of the polymerizable monomers include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-
Ethylstyrene, 44-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n
-hexylstyrene, p-n-octylstyrene, p-
n-nonylstyrene, p-n-decylstyrene, p-n
- Styrene and its derivatives such as dodecylstyrene, n-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene, m PVC.

Vinyl halides such as vinylidene chloride, vinyl bromide, vinyl fluoride, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, Isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-pok ethyl acrylate, phenyl acrylate, α-
Methyl chloroacrylate, methyl methacrylate.

Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate.

α-methylene such as n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylamine ethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, etc. Aliphatic monocarboxylic acid esters, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyglobyl acrylate.

Acrylic acid or methacrylic acid derivatives such as 2-hydroxyethyl methacrylate, 2-hydroxyglobyl methacrylate, and optionally acrylic acid.

Methacrylic acid, maleic acid, fumaric acid, etc. can also be used. In addition, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropyl benyl ketone, N-vinyl pyrrole, N-vinyl carbazole, and N-vinylindole. .

N-vinyl compounds such as N-vinylpyrrolidone.

Vinylnaphthalene salt can be used alone or in combination of 21m or more. Among these polymerizable monomers, the use of 40 to 100% by weight of styrene or styrene derivatives provides excellent fixing properties when the toner is copied onto paper using an electrophotographic copying device.

Further, as the polymerizable monomer of the present invention, a compound having two or more polymerizable double bonds that can serve as a crosslinking agent can also be used in part. For example, divinylbenzene.

Aromatic divinyl compounds such as divinylnaphthalene and their derivatives; diethylene carboxylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol triacrylate, trimethylolpropane triacrylate; vinyl ether,
Divinyl compounds such as divinyl sulfite and compounds having three or more vinyl groups can be used alone or as a mixture. The amount of the crosslinking agent used is preferably 0 to 20% by weight, particularly preferably 0 to 5% by weight, based on the total amount of polymerizable monomers.

The aqueous medium used in emulsion polymerization is mainly water. What is the ratio of the above polymerizable monomer to the aqueous medium?

The weight ratio of the former/latter is preferably 40/60 to 90/10. If this ratio is too small, emulsion polymerization will be difficult, and if this ratio is too large, the yield will decrease.

As the emulsifier, anionic surfactants, cationic surfactants, zwitterionic surfactants, and nonionic surfactants can be used. Among these, when producing negatively chargeable toner, anionic surfactants are used,
When producing a positively chargeable toner, it is preferable to use a cationic surfactant. In these cases, in order to improve dispersion stability, it is preferable to use a nonionic surfactant in combination.

Examples of anionic surfactants include fatty acid salts such as sodium oleate and potassium castor oil, alkylbenzenesulfonates such as sodium laurylphonate, alkylnaphthalenesulfonates, dialkylsulfosuccinates, alkylphosphate ester salts, and naphthalenesulfonic acid. Formalin condensates, polyoxyethylene alkyl sulfate salts, etc.

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 Examples include oxypropylene block polymers.

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 the zwitterionic surfactant include lauryltrimethylammonium chloride.

The amount of emulsifier used is 0.01 to 1 per polymerizable monomer.
0% by weight is preferred, particularly 0.5-5% by weight. If the amount of emulsifier used is too small, stable emulsion polymerization will be difficult, and if it is too large, the resulting toner will have poor moisture resistance.

Stabilizers include polyvinyl alcohol, starch,
There are water-soluble polymers such as methylcellulose, carboxymethylcellulose, and hydroxyethylcellulose, and these are preferably used in an amount of 0 to 1% by weight based on the monopolymerizable monomer.

Examples of water-soluble polymerization initiators that can be used in the present invention include persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide, 4,4'-azobiscyanovaleric acid, and 2,2'-azobis( 2-amidinopropane)
Dihydrochloride, t-butyl hydroperoxide, cumene hydroperoxide, etc. can be used. In particular, when persulfate is used, the sulfate anion radical (804-), which serves as the initiation active site, exists on the surface of the monomer, and the hydrophilic group of the 804-group and the electrostatic charge stabilize the sulfate particles. It is easy to obtain an emulsion with uniform particle size.

The amount used is preferably 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight, based on the polymerizable monomer.

If the amount of polymerization initiator is too small, the polymerizable monomer will not be completely polymerized and will remain in the toner, impairing the properties of the toner.

As a polymerization initiator, benzoyl peroxide, t-
Peroxides such as butyl perbenzoate.

Oil-soluble polymerization initiators such as age compounds such as azobisisobutyronitrile and azobisisobutylvaleronitrile can be used in combination. The oil-soluble polymerization initiator is preferably used in an amount of 100% by weight or less based on the water-soluble polymerization initiator.

The above 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. Although it is not necessary to use a reducing agent.

When used, it is preferably used in an amount equal to or less than the amount of the water-soluble polymerization initiator.

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

Colorants preferably used in the present invention include:

Pigments or dyes such as various carbon blacks, nigrosine dyes (C,1,N11504
15), Aniline Blue (C01, Nα5o4o5).

Calco oil blue (C, 1, Na azoec Bl
ue 3) + chrome yellow (C, I, N111
4090), ultramarine blue (C, L fish 7710)
3), DuPont Oil Red (C, 1, & 26105)
, Orient Oil Red $330 (C,L Na6
0505), quinoline yellow (C, I, 47005)
, methylene blue chloride (C, I, Na52015
), phthalocyanine blue (C, 1, Na74160)
,? Lachite green oxalate (C,1,Nα42
000), lamp black (C, I, N [L77266
), rose bengal (C, 1, Nα45435), oil black, azo oil black, etc. can be used alone or in combination. These colorants can be used in any amount, but in order to obtain the required concentration and for economic reasons, the colorants should be present in the toner at about 1 to 30% by weight, preferably 5 to 15% by weight. used in percentages.

The pigment or dye may be subjected to various treatments for the purpose of increasing its dispersibility in the 9-polymerization reaction system or in the toner of the present invention.

The treatment includes 9, for example, nigrosine dye (C, I).

m5o41s) using an organic acid such as stearic acid or maleic acid.

Among these colorants, particularly preferred for the toner of the present invention are various carbon blacks, such as furnace black, channel black, thermal black, acetylene black, lamp black, and the like. Furthermore, the carbon black may be surface-treated. As for surface treatment.

Examples include oxidation treatment using various oxidizing agents such as oxygen, ozone, and nitric acid, and surface adsorption treatment with organic acid esters such as dibutyl phthalate and dioctyl phthalate.

When using carbon black as a colorant, it is preferred to use grafted carbon black. What is grafted carbon black?

It is obtained by polymerizing the above polymerizable monomers in the presence of carbon black by a method such as bulk polymerization or solution polymerization. The polymer component of grafted carbon black is
It is preferably 50% by weight or less, particularly preferably 30% by weight or less, based on the grafted carbon black. Grafted carbon black is preferable because it has excellent dispersion stability during emulsion polymerization, but if the monopolymer component is too large, the viscosity tends to become too high when dispersed in a polymerizable monomer, reducing workability. do. The amount of grafted carbon black used is preferably determined by the amount of carbon black component.

Magnetic powder is used when manufacturing magnetic toner.

This can double as a coloring agent. Preferred magnetic powders include, for example, oxides or compounds of iron such as magnetite or ferrite, or ferromagnetic elements such as nickel and cobalt. These magnetic powders are preferably in powder form with a particle size of 0.01 to 3 μm, and even if the surface of the magnetic powder is treated with resin 1 titanium coupling agent, silane coupling agent, higher fatty acid metal salt, etc. good. These magnetic substances have a 20 to 8
It can be contained in an amount of 0% by weight, preferably 35-70% by weight. Less than this amount may be used as a coloring agent.

An offset inhibitor is used as necessary. The anti-offset agent is present in the system in various forms during polymerization and can be incorporated into the toner product. Alternatively, the anti-offset agent can be added later to the toner of the present invention in which no anti-offset agent is present. Various natural waxes such as carnauba wax,
Hydrogenated castor oil or low molecular weight olefin polymers can be used in the present invention, and preferably low molecular weight olefin polymers are used. As this low molecular weight olefin polymer, a low molecular weight polymer of olefin or a copolymer of an olefin and a monomer other than olefin is used. Here, the olefins include ethylene, propylene,
Examples of monomers other than olefins include acrylic esters and methacrylic esters.

Examples of this low molecular weight olefin polymer include 1.

The polyalkylene described in JP-A-55-153944 and the low molecular weight olefin copolymer described in JP-A-50-93647 can be used.

The molecular weight of the low molecular weight olefin polymer of the present invention may be within the concept of low molecular weight in ordinary polymer compounds, but generally the weight average molecular weight (Mw) is 1,000.
0-45,000, preferably 2.000-6. O
It belongs to OO.

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 preferred.

There is no particular limit to the amount of the low molecular weight olefin polymer that can be used in the present invention, but it is preferably in the range of 0 to 30 weight 1iis based on the weight of the toner.

Preferably it is used in an amount of 1 to 30% by weight. If the amount of the low molecular weight olefin polymer is too small, no offset effect will be produced by adding it, and if it exceeds 30% by weight, gelation may occur during the polymerization reaction.

Furthermore, a fluidity improver, a cleaning performance improver, etc. can be used as necessary. Although these can be present in the polymerization reaction system and in the product toner, they are preferably externally added to the product toner afterwards. The content of each of these is preferably 0% to 3% by weight based on the toner of the present invention. Fluidity improvers include silane,
Titanium.

There are oxides of aluminum, calcium, magnesium, and magnesium, or those obtained by hydrophobizing the above oxides with a titanium coupling agent or a silane coupling agent. Cleaning performance improvers include zinc stearate, lithium stearate, and lauric acid. These include metal salts of higher fatty acids such as magnesium or aromatic acid esters such as pentaerythritol benzoate.

In the present invention, the charging lid and charging polarity of the product toner can be freely adjusted by selecting the polymerizable monomer and colorant. A charge control agent can also be used in the toner of the invention in combination with the colorant.

Charge control agents preferably used in the present invention include azo dyes such as Spiron Black TRH and Spiro/Black TPH (Hodogaya Chemical), p-fluorobenzoic acid, p-nitrobenzoic acid, and 2.4-di-t Examples include aromatic acid derivatives such as -butylsalicylic acid, tin compounds such as dibutyl-tin oxide, and dioctyl-tin oxide.

These are preferably used in an amount of 0 to 5% by weight based on the 9-polymerizable monomer.

In the present invention, after producing the main resin component by emulsion polymerization, a salting-out agent is added to the obtained emulsion polymerization solution to perform salting-out. In this way, by appropriately aggregating the particles in the emulsion polymerization liquid, a toner having a larger average particle size than the particles in the emulsion polymerization liquid and having an incomplete spherical shape and requiring pulverization can be obtained. Suitable resin particles can be obtained.

Here, it is preferable to adjust the particle size distribution of the aggregated particles to 1 to 100 μm.

It is preferable to adjust the thickness to 3 to 70 μm.

It is most preferable to adjust the thickness so that the main component is one having a diameter of 5 to 25 μm. The average particle size is preferably adjusted to 9 to 15 μm. For the above adjustment, the salting-out agent should be added in an amount of 0.1 to 5 times the weight of the emulsifier in the emulsion polymerization solution.
It is preferable to use 0.3 to 3 times as much. If the amount of the salting-out agent used is too small, the salting-out effect will be insufficient, and if it is too large, the moisture resistance of the toner will be poor and the average particle size of the particles will become too large.

Since imperfectly spherical toner particles are obtained by the salting out process with the toner particles, the toner particles have excellent cleaning properties. Furthermore, since the emulsifier is also removed by the salting out step, blocking resistance and charging stability are also improved.

In this salting-out process, the emulsion polymerization liquid and the salting-out agent are mixed,
This can be carried out by dropping the emulsion polymerization liquid little by little into the salting-out agent aqueous solution while stirring, or by mixing the salting-out agent aqueous solution and the emulsion polymerization liquid at a constant ratio.

The temperature during the salting out step is not particularly limited, but is preferably room temperature to 150° C., and is particularly preferably carried out at a temperature equal to or higher than the softening point of the main resin component.

When salting out is carried out at a temperature below the softening point, it is particularly preferred to subsequently heat the salting out solution to a temperature above the softening point of the polymer. This heat treatment increases the bulk density of the particles of the main resin component, making them moisture resistant.

Offset resistance and durability are improved.

In the salting out process, a large amount of salting out agent is added to the emulsion polymerization solution,
Another option is to obtain a large coagulate and grind it to a particle size suitable for toner, but this method allows additives to be dispersed more uniformly in the resin than toner produced by grinding. However, since the toner is pulverized, it takes a shape closer to that of the pulverized toner than the toner according to the present invention, and therefore is inferior in cleaning properties and toner fluidity.

On the other hand, in the present invention, the particles obtained by salting out can be made into a toner as is or by only being classified, and the shape of the toner particles is as follows.

Unlike the pulverized toner, which has a completely different asymmetrical spherical shape, it has an imperfectly spherical shape, not a groove or a perfect sphere, so it has excellent cleaning properties.

Examples of salting-out agents include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as formic acid and oxalic acid, and water-soluble metal salts of these acids and alkaline earth metals, aluminum, etc. 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 of these and an inorganic acid. . These salting-out agents are 0.1 to 1.011 ift.
% aqueous solution, especially 0.1 to 5% by weight aqueous solution.

After salting out, toner particles can be obtained by centrifugal dehydration, further washing, drying and, if necessary, classification.

Here, washing is preferable in order to completely remove the emulsifier attached to each particle, and in addition to the above-mentioned salting out,
Charging stability and blocking properties can be improved.

Washing is preferably carried out with warm water at a temperature of 40 to 60°C.

Note that the above-described heat treatment after salting out may be inserted during the washing step or between seven or more washing steps.

The toner obtained according to the present invention can be used in various development processes, such as the cascade development method described in U.S. Pat. No. 2,618,552, the magnetic brush method described in U.S. Pat. No. 2,874,065, the Patent No. 2.221,
Powder cloud method described in No. 776, Touchdown development method described in U.S. Pat. It can be used in the so-called bipolar magnetic toning method, which uses magnetic toner produced by a suitable method, and the so-called bipolar magnetic chi method, in which the necessary toner charge is obtained by frictional charging of magnetic toners.

Furthermore, the toner obtained according to the present invention can be used in various fixing methods9.
For example, it can be used in so-called oil-less and oil-coated heat roll methods, flash methods, oven methods, pressure fixing methods, and the like.

Furthermore, the toner of the present invention can be used in various cleaning methods 9, such as the so-called fur brush method and blade method.

(Example) Next, an example of the present invention will be shown. Hereinafter, ``chi'' means % by weight.

Example 1 (1) Production of emulsion polymerization solution 31! In a stainless steel beaker, add 100 g of grafted carbon (Craft Carbon GP-E-2 manufactured by Ryoyu Kogyo ■), 120 g of styrene 4009° butyl acrylate as a polymerizable monomer, and 0.6 g of t-dodecyl mercaptan as a chain transfer agent. 300 Or, p in a homo mixer,
The mixture was mixed and dispersed at m for 30 minutes.

Next, add 1300g of ion-exchanged water to this carbon dispersion.
Anionic surfactant sodium dodecylbenzenesulfonate 129, nonionic surfactant Noniball PB-68 (Sanyo Chemical Co., Ltd. oxypropylene-oxyethylene block polymer) 3 g, Neuge/EA170 (Dai-Kogyo Co., Ltd.) were used as emulsifiers. 3 g of polyoxyethylene glycol nonylphenyl ether (manufactured by Lai) was polymerized and emulsified to obtain a black pre-emulsion.

Next, stirrer, nitrogen inlet, thermometer, condenser tD
The black gray emulsion was transferred to a 4*3-J paralp flask, and the mixture was polymerized at 70°C for 5 hours under a nitrogen stream, and then cooled to obtain an emulsion polymerization solution.

The polymerization rate at this time was 99.5'fi or more. The molecular weight of the polymer 9 was measured by gel chromatography using a standard polystyrene calibration curve, and the weight average molecular weight (Mw) was 86,000, and the number average molecular weight (Mw) was 86,000.
n) It was 30,000.

(2) Salting out step/final step The above emulsion polymerization solution 11 was heated to 30°C to form a MgSO41 aqueous solution 21! The temperature of the aqueous solution was raised to 30℃ while stirring thoroughly.
The solution was uniformly added dropwise over about 30 minutes to effect salting out.

The mixture was kept at this temperature for an additional 30 minutes and cooled to room temperature. Next, this slurry was dehydrated using a centrifugal dehydrator, and then heated at 50°C.
Washing was repeated three times with warm water. Then, it was dried in a dryer at 30 to 35°C to obtain a toner. The particle size of the obtained toner was measured using a Coulter counter, and the particle size was 1 to 50 μm, with an average particle size of 13 μm. Further, the glass transition point (Tg) was measured with a differential scanning calorimetry needle and found to be 73°C. This toner is further processed using a zigzag classifier (
10oMZR, Alpinsha 1! When the powder was classified into 5 to 25 μm using a sieve, the yield was 90 μm compared to that before classification. In the Examples and Comparative Examples below, particle diameters and average particle diameters were measured using a Coulter counter, and glass transition points were measured using a differential scanning calorimeter.

Classification was performed using a zigzag classifier.

Examples 2 to 6 Emulsion polymerization liquid 11 obtained in Example 1! 9 was added dropwise uniformly over about 30 minutes to a salting-out agent aqueous solution (shown in Table 1) heated to the salting-out temperature shown in Table 1 to effect salting out.

During salting out, the above-mentioned salting-out temperature was maintained, and after the emulsion polymerization liquid was added dropwise, the temperature was maintained at the same temperature as the above-mentioned salting-out temperature for 30 minutes, and then cooled to room temperature. After dehydrating the obtained salting-out solution (slurry) using a hypocenter dehydrator.

Washed three times with 50°C warm water. Then, it was dried in a dryer at 30 to 35°C to obtain toner particles.

The particle size, average particle size, yield of particles of 5 to 25 μm, and glass transition point of the main resin component of this toner particle are shown in Table 1 together with the results of Example 1.

The classified toners obtained in Examples 1 to 6 were used.

A plain paper copying machine (manufactured by Konishi Roku Photo Industry ■ + u-Bix 1.600) using a commercially available insulating carrier was used.

The electrophotographic toner properties were tested. However, each toner contains hydrophobic silica (Nippon Aerosil) as a fluidity improver.
1't-972) and zinc stearate were externally added to the above toner in amounts of 0.6 and 0.1, respectively. The test results are shown in Table 1.

Below are blank spaces Examples 7 to 9 Emulsion polymerization liquid II obtained in Example 1! And salting out was carried out in the same manner as in Examples 1 to 6 using a salting out agent aqueous solution (shown in Table 2) heated to the salting out temperature shown in Table 2. The obtained salting-out solution (slurry) was transferred to an autoclave and heated at the heat treatment temperature shown in Table 1 and Table 2 for 30 minutes. This ridge is cooled and Example 1
The toner was obtained by dehydration, water washing and drying in the same manner as in steps 6 to 6.

Table 2 shows the particle size, average particle size, yield of particles of 5 to 25 μm, and electrophotographic properties tested in the same manner as Examples 1 to 6 of the obtained toner.

Table 2 Characteristic Salt Salt・1 Salt↓ Do [-1 7 T 1+3 1-Ya・1 Gate-1 Ri-1 Ru-]! Example 10 (1) Manufacturing process of emulsion polymerization solution Grafted carbon 1009. Styrene 3609, butyl methacrylate 1809. 6 g of methacrylic acid, 0.6 g of t-dodecyl mercaptan, and 6 g of low molecular weight polypropylene (Viscol 550P, Sanyo Chemical Industries ■ trade name) were mixed and dispersed in a homomixer at 300 Orp and pom for 30 minutes.

Next, in ion-exchanged water 15009, 18 g of sodium dodecylbenzenesulfonate, 4 g of nonionic surfactant Noniball PE-68 (trade name of Sanyo Chemical Industry Co., Ltd.), 4 g of nonionic surfactant Noigen EA170 (trade name of Daiichi Kogyo Seiyaku Co., Ltd.), 9g of ammonium persulfate and 3g of hydrogen peroxide
Add the aqueous solution in which g is dissolved into a homomixer and mix at room temperature for 3
A black pre-emulsion was obtained by emulsifying at 00Or and p8m for 30 minutes.

This black blur emulsion is 31! The mixture was transferred to four separate parallel flasks, polymerized at 70° C. for 5 hours under a nitrogen stream, and then cooled to obtain an emulsion polymerization solution.

The polymerization rate at this time was 99.51 or more, and the molecular weight of the polymer obtained in the same manner as in Example 1 was 105.000.
Mn was 41,000.

(2) Salting out process/final process According to the salting-out agent aqueous solution and salting-out temperature shown in Table 3.

Toner particles were obtained in the same manner as in Examples 1 to 6.

Example 11 Emulsion polymerization liquid il obtained in Example 10! , Example 7 using the aqueous salting-out agent solution, salting-out temperature, and heat treatment temperature shown in Table 3.
A toner was obtained by carrying out the salting out step and final step in the same manner as in steps 9 to 9.

Particle size of toners obtained in Examples 10 and 11.

Table 3 shows the average particle diameter, the yield of particles of 5 to 25 μm, the glass transition point of the main resin component, and the electrophotographic properties tested in the same manner as in Examples 1 to 6.

Table 3 below: Characteristics Example 12 (1) In the manufacturing process m1 of emulsion polymerization solution Example 10, carbon black (carbon black ÷ 44. Mitsubishi Chemical Corporation ■Product name, furnace black type carbon black) was used instead of grafted carbon 1009. An emulsion polymerization solution was obtained in the same manner as in Example 1O, except that 30 g of styrene was used, 414 g of styrene was used, and low molecular weight polypropylene and hydrogen peroxide were not used.

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

(2) Salting out process/final process The above emulsion polymerization liquid 11! Toners were obtained in the same manner as in Examples 1 to 6 using the aqueous salting-out agent solutions and salting-out temperatures shown in Table 4.

Examples 13 and 14 Emulsion polymerization liquid 111 obtained in Example 12 Examples 7 to 11 were prepared using the salting-out agent aqueous solution, salting-out temperature, and heat treatment temperature shown in Table 4.
A toner was obtained in the same manner as in Example 9.

The particle size, average molecular weight, yield of particles of 5 to 25 μm, glass transition point of the main resin component, and electrophotographic properties measured in the same manner as Examples 1 to 6 of the toners obtained in Examples 12 to 14 are shown. 4.

Table 4 Characteristic Comparative Example 1 (Production of toner by suspension polymerization) Styrene 70
g, butyl methacrylate 30g.

Thoroughly knead 15 g of grafted carbon and 2 g of benzoyl peroxide in a homomixer, and mix 1 part of tricalcium phosphate.
% aqueous solution SOOG and mix with a homomixer for another 3000
Dispersion was carried out for 30 minutes at r, p, m.

This dispersion was transferred to a flask and subjected to suspension polymerization 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 dried to obtain a toner. The Mw of the resin in this toner is 110,000. Mn is 5
It was 0.000.

Comparative Example 2 (Production of toner by spray drying after emulsion polymerization) The emulsion polymerization solution obtained in Example 1 was spray dried at a temperature of 110° C. to obtain a toner.

Comparative Example 3 (Crushing method) Styrene/butyl methacrylate - 70/30 (weight ratio) 9 Molecular weight Mw 70.
Polymers of 000 and Mn 30,000 were prepared, and the solvent was removed under reduced pressure to remove toluene to form a white solid.

This polymer 1.0009 was kneaded with carbon black 509, 10 g of copper phthalocyanine, and 20 g of low molecular weight polypropylene (Viscol 550P, trade name of Sanyo Chemical Industries, Ltd.) using two rolls, and pulverized using a jet mill to obtain a toner.

Particle size and average particle size of toners obtained in Comparative Examples 1 to 3, 5
Table 5 shows the yield of ~25 μm particles, the glass transition temperature of the main resin component, and the electrophotographic properties tested in the same manner as Examples 1 to 6.
Shown below.

Table 5 Characteristics! ! Evaluation of electrophotographic properties in Examples 1 to 14 and Comparative Examples 1 to 3 was performed as follows.

(Al Resolution: Electrophotography Society Test Chart Nl1
1 and the respective prepared developers were used to copy onto plain paper. We compared and evaluated whether the copied images could be read in detail.

tb) Image density: Judgment was made by measuring the density of the black part of the copied paper with a densitometer in the same manner as the resolution.

Gradation: Evaluated in the same manner as the resolution using the 11-level gray area in the center of the test chart.

(C1 Cleanability: Continuous copying was carried out using a copying machine using the respective prepared developers under conditions of a hot water temperature of 30° C. and a humidity of 801 RH.

The process leading up to the occurrence of cleaning failure The evaluation was based on the number of pieces.

(d) Blocking property: Examples 1 to 14. Comparative example 1
The toner prepared in steps 3 to 3 was left for 72 hours at 50° C. and 95° humidity to determine whether or not the toner was blocked.

◎: Very good O: Excellent △: Slightly inferior ×: Inferior It was evaluated as

(e) Charge stability: Each prepared developer is stirred in a copying machine, the amount of charge is measured at regular intervals, and judgment is made based on the change in the amount of charge.

◎: Very good ○; Excellent △: Slightly inferior ×: Inferior It was evaluated as

Using the toners obtained in Examples 1 to 14 and Comparative Examples 1 to 3, a plain paper copier (N made by Copia Co., Ltd.) using a conductive carrier was used.
Table 6 shows the results of a test for resolution 9 image density and gradation in the same manner as the electrophotographic characteristics test described above using a 3000-Pixel C-3000.

Margin below (Effect of the invention) According to the present invention, resolution is achieved by utilizing emulsion polymerization method.

It is possible to obtain an electrophotographic toner that is suitable for dry development and has excellent image density and 9-gradation properties, and particularly excellent cleaning properties, charging stability, and blocking properties.

Continuation of page 1 ＠Inventor　Massive Book　Hitachi City Kuku 4 Inside the venue @Inventor Takashi Ohno Kuku 4, Hitachi City Inside the venue

Claims (1)

[Claims] 1. A main resin component is produced by emulsion polymerizing a polymerizable monomer in the presence of a colorant and/or magnetic powder. A method for producing an electrophotographic toner, which comprises salting out the obtained emulsion polymerization liquid so that the particles of the emulsion polymerization liquid have a diameter of 9, which is suitable for the toner. 2. The method for producing an electrophotographic toner according to claim 1, wherein the salting-out agent is used in an amount of 0.1 to 5 times the weight of the emulsifier in the emulsion polymerization solution during the salting out. 3. The electrophotographic toner according to claim 1 or 2, wherein at least one compound selected from inorganic acids, organic acids, and water-soluble metal salts thereof is used as a salting-out agent during salting out. Production method.