JPS62267762A - Production of polymerized toner - Google Patents

Abstract

PURPOSE:To obtain a polymerized toner which has a narrow grain size distribution and good electric chargeability and yields a good image by dispersing a monomer compn. contg. a polymerizable monomer and magnetic material subjected to a prescribed surface treatment into an aq. phase contg. a dispersant and subjecting the dispersion to a suspension polymn. CONSTITUTION:The polymerized toner is formed by dispersing the monomer compn. contg. at least the polymerizable monomer and the magnetic material subjected to the surface treatment by a peroxide polymn. initiator into the aq. phase contg. the dispersant and suspending and polymerizing the dispersion. The peroxide having <=100 deg.C at which the half-life is 1min is more preferable, for which a diisobutyl peroxide, t-butyloxyneodecanoate, etc., are used. The magnetic material is obtd. by treating the same in other org. solvents and the polymerizable monomer compn. of styrene and the deriv. and (meth)acrylates with the org. peroxide. The org. peroxide is preferably used at 0.5-20pts.wt. per 100pts.wt. magnetic material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner used in a method for visualizing a latent image.

[Prior Art] Toner for this purpose is for forming and recording images, for example in electrophotography,
Including U.S. Patent No. 2,297,891, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748
As described in the above publications, a number of methods are known, and generally, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is transferred to a photoreceptor. After developing with toner and transferring the toner image to a transfer member such as paper as necessary, it is fixed by heat, pressure, a hot pressure roller, solvent vapor, etc. to obtain a copy. Various methods have been proposed for developing with toner, such as the magnetic brush method described in U.S. Pat. No. 2,874,083, and U.S. Pat. No. 2, Ei 18,552.
In addition to the cascade development method described in US Pat. No. 2,221.7713 and the powder cloud method described in US Pat. Among these developing methods, the magnetic brush method, cascade method, liquid developing method, etc., which use a developer mainly consisting of toner and carrier, are in particular widely put into practical use.

All of these methods are excellent methods that can relatively stably obtain good images, but on the other hand, they have common problems associated with two-component developers, such as deterioration of the carrier and fluctuations in the mixing ratio of toner and carrier. There is. In order to avoid such problems, various development methods using component-based developers consisting only of toner have been proposed, but among them, many methods using developers consisting of magnetic toner particles are superior. The so-called induced development method described in Japanese Patent Publication No. 37-491 is well known.

This method uses conductive and magnetic toner and magnets.
A magnetic brush made of toner is formed by adhering to an internal sleeve, and the magnetic brush is brought into contact with an electrostatic latent image carrier to develop a latent image with the toner. In this developing method, since the toner has conductivity, when a magnetic brush is placed opposite the electrostatic latent image, charges of opposite polarity to the electrostatic latent image are induced in the toner, and the toner with the induced charges is , the latent image is developed based on the electrical attraction between the electrostatic latent images. In addition, insulating magnetic toner is attached to a sleeve containing a magnet to form a toner magnetic brush, the toner is charged by friction with the sleeve, and the magnetic brush is brought into contact with or close to the electrostatic latent image carrier. A method of developing a latent image with toner is also known. For example, Japanese Patent Application Laid-Open No. 49-1999 uses capsule magnetic toner. No. 17739, JP-A-50-4563 using insulating magnetic toner
The developing method is described in detail in Publication No. 9 and the like.

In the development method using these -component developers, since the developer does not contain a carrier, there is no need to adjust the mixing ratio of carrier and toner, and a stirring operation is required to mix the carrier and toner sufficiently uniformly. Since this is not necessary, there is an advantage that the entire developing device can be constructed simply and compactly. Furthermore, there is no problem such as deterioration in developed image quality due to deterioration of the carrier over time.

In these magnetic toners, a considerable amount of magnetic fine particles are generally dispersed in a binder resin, but the dispersibility of these magnetic fine particles in the binder resin is poor and it is difficult to obtain a uniform dispersion. Furthermore, even if a toner is dispersed to some extent through a sufficient kneading process, breakage occurs at the interface between the magnetic fine particles and the binder resin during the first pulverization process, resulting in magnetic particles being present on the toner surface, resulting in a decrease in electrical resistance. This tends to lead to a decrease in moisture resistance and a decrease in moisture resistance. Furthermore, differences occur in the content of magnetic particles among the toner particles, resulting in non-uniform hiding power.

On the other hand, in order to overcome the problems of toner produced by these pulverization methods, a method for producing toner using a suspension polymerization method has been proposed. In the suspension polymerization method, a monomer system in which a polymerizable monomer, a magnetic substance, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, a coloring agent, and other additives are uniformly dissolved or dispersed, is mixed with a dispersion stabilizer. Toner particles having a desired particle size are obtained by dispersing the toner particles in the aqueous phase containing the toner particles using a suitable stirrer and simultaneously carrying out a polymerization reaction. Since the suspension polymerization method does not include a mechanical crushing step, there are no inconveniences caused by the crushing that occur in the crushing method, but since the monomer system containing magnetic fine particles is dispersed in the aqueous phase, this dispersion - In the polymerization process, magnetic fine particles that are generally wood-philic are unevenly distributed on the surface of the toner particles, resulting in the same problems as the pulverization method.

In order to improve the dispersibility of magnetic fine particles in polymerizable monomers and binder resins, various treatments for magnetic particles have been proposed. etc.), treatment with a silane coupling agent (see JP-A-54-127329, etc.), titanium coupling agent (JP-A-55-2),
6519, etc.) has been proposed. However, even these treatments are insufficient to uniformly disperse the magnetic particles in the polymerizable monomer and binder resin, and the bond strength between the magnetic particles and the binder resin is also insufficient. . Furthermore, silane coupling agents and titanium coupling agents also generate impurities due to hydrolysis.
There is also a risk that the properties as a toner will be adversely affected.

As a result, the resulting polymerized toner had relatively poor physical properties as a toner compared to a toner obtained through a conventionally known kneading/pulverization process.

Furthermore, in the production of polymerized toner containing a magnetic material therein, the magnetic material is often subjected to a polymerization reaction.

This may have had a negative impact on the line. As a result, in the production of the polymerized toner, it is necessary to use an expensive azo polymerization initiator that has relatively less adverse effects on the polymerization reaction than peroxide polymerization initiators.

As described above, treatment of the magnetic material is an important issue in polymerized toners, and it is desired that the toner has suitable affinity and dispersibility, and has little inhibition of polymerization.

[Problems to be Solved by the Invention] A first object of the present invention is to provide a manufacturing method that provides a polymerized toner with a narrow particle size distribution.

A second object of the present invention is to provide a method for producing a polymerized toner that has good chargeability regardless of humidity, always exhibits stable chargeability during use, and provides good images.

[Means and effects for solving the problem] The object is to disperse a monomer composition containing at least a polymerizable monomer and a magnetic material in an aqueous phase containing a dispersant, and to perform suspension polymerization. This is achieved by a method for producing a polymerized toner, characterized in that a magnetic material whose surface has been treated with a peroxide-based polymerization initiator is used as the magnetic material.

The present invention will be explained in detail below.

In order to achieve the object of the present invention, the inventors of the present invention have conducted extensive studies on the factors governing the particle size distribution of polymerized toner produced by suspension polymerization, and have found that the dispersion state of the magnetic material and the particle size distribution correspond well to each other. I discovered that.

In view of the above-mentioned situation, the inventors of the present invention have conducted intensive studies and have arrived at the present invention. The present invention relates to a polymerized toner characterized in that the magnetic material is treated with an organic peroxide when the magnetic material is dispersed in a polymerizable monomer phase, and to the production of the polymerized toner.

Further, the polymerized toner is obtained by initiating a polymerization reaction using a peroxide-based polymerization initiator.

The present invention will be described more specifically as follows.

(D. Processing step for magnetic material) A step in which the magnetic material is dispersed in the coexistence of an organic peroxide, processed to form secondary particles, or processed in parallel with the processing to form secondary particles.

(ii) Granulation step A step mainly consisting of granulation of a monomer composition in which the magnetic material obtained in step (i) and a peroxide polymerization initiator are newly added.

(iii) Polymerization step of polymerizing the granules obtained in step (i). The polymerization reaction is initiated by the peroxide polymerization initiator added in step (i).

As is clear from the above steps, (1) treatment step and (i)
) The action of the peroxide used in each step of the granulation process is different.

The organic peroxide used in the treatment step (i) is:
It is preferable that the temperature at which the half-life is 1 minute is 100° C. or lower, and a temperature higher than 100° C. is not preferable because a sufficient treatment effect cannot be obtained.

Examples of the organic peroxide preferably used in the present invention include diisobutyl peroxide, t-butyl peroxyneodecanoate, diacetyl peroxide,
Diprobionyl peroxide, dilauroyl peroxide, di-n-propyl peroxy dicarponate, di-5ec-butyl peroxy dicarponate, di(isopropylperoxy) dicarponate, di(2-ethylhexylperoxy) dicarponate, di(2- Examples include ethoxyethylperoxy) dicarponate, di(methoxyisopropylperoxy) dicarponate, di(3-methoxybutylperoxy) dicarponate, di(cyclohexylperoxy) dicarponate, bis-(4-t-butylcyclohexylperoxy) dicarponate, and the like.

The magnetic material according to the present invention includes toluene, xylene, acetone,
Organic peroxides can be used in organic solvents such as methyl ethyl ketone, ethyl acetate, methanol, and ethanol, or in polymerizable monomer compositions of styrene, its derivatives, and (meth)grilate esters under conditions that do not substantially polymerize. Obtained by processing. Preferably, the treatment is carried out in a polymerizable monomer composition.

In the present invention, the organic peroxide is preferably used in an amount of 0.5 to 20 parts by weight, more preferably 2 to 12 parts by weight, per 100 parts by weight of the magnetic material.

If the amount is less than 0.5 parts by weight, there will be no sufficient treatment effect, and if it is more than 20 parts by weight, heat generation will be significant, resulting in a dangerous situation, which is not preferable.

In the present invention, the temperature when treating the magnetic material with an organic peroxide is preferably 40 to 100°C, more preferably 60 to 100°C.
Preferably, the temperature is 90°C. At a temperature of 40° C. or lower, the treatment of the magnetic material becomes insufficient, and at a temperature of 100° C. or higher, the organic peroxide decomposes significantly, resulting in large heat generation, which is not preferable.

In the present invention, the time required for processing the magnetic material varies depending on the organic peroxide and the processing temperature, but it is preferably the time when the remaining amount of organic peroxide becomes 174 or less of the initial amount, and the time when 1/4 or more remains. In this case, the treatment of magnetic material is insufficient.

It is assumed that the achievement of the objective by magnetic materials treated with these organic peroxides is due to the reactivity of radicals, unlike initiators such as azo-based initiators.

The peroxide polymerization initiator added in the granulation step (ii) and used in the polymerization step (1i) has a half-life of 10
It is preferable that the temperature for the time is 50 to 70°C,
If the temperature is lower than 50°C or higher than 70°C, the polymerization reaction cannot be sufficiently controlled, and a polymerized toner that satisfies the desired physical properties cannot be obtained.

Examples of peroxide-based polymerization initiators preferably used in the present invention include diacetyl peroxide, dipropionyl peroxide, dioctanoyl peroxide,
diacetyl peroxide, dilauroyl peroxide,
Bis(3,3,5-)dimethylhexyl) peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, peroxysuccinic acid, t-butylperoxypivalate, t-butylperoxyneodecano Eight, (1,3
, 3-tetramethylbutylperoxy) 2-ethylhexanoate, 2,5-dimethyl 2,5 di(peroxy 2
-ethylhexanoyl)hexane and the like.

In the present invention, the peroxide polymerization initiator is preferably used in an amount of 0.5 to 10 parts by weight, more preferably 1.5 to 7 parts by weight, based on 100 parts by weight of the monomer composition including the magnetic material. It is preferable that if the amount is less than 0.5 parts by weight, the polymerization reaction will not proceed, and if it is more than 10 parts by weight, it will be difficult to control the polymerization reaction.

The magnetic particles that can be used in the present invention include substances that are magnetized when placed in a magnetic field, such as powders of ferromagnetic metals and metals such as iron, cobalt, and nickel, or alloys such as magnetite, hematite, and ferrite. and compound powders. Particle size is 0.05-5 gm, preferably 0
．． Magnetic fine particles having a particle diameter of 1 to Igm are used. The content of the magnetic particles is 10 to 60% by weight based on the weight of the toner.
Preferably it is 25 to 50% by weight.

The magnetic material used in the present invention may be previously subjected to hydrophobization treatment using a known technique such as a silane coupling agent or a titanium coupling agent, or it may be used as is without hydrophobization treatment. Alternatively, two or more types of magnetic bodies treated with different hydrophobizing agents may be used in combination, and two or more types of magnetic bodies treated with different degrees of hydrophobization treatment can also be used in combination.

In the present invention, the polymerization initiator used in the granulation step (i) may be a combination of a peroxide polymerization initiator and an azo polymerization initiator, or a peroxide polymerization initiator used in combination with an azo polymerization initiator. It may also be used in place of a drug.

Examples of polymerizable monomers applicable to the present invention include styrene,
0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, P-phenylstyrene, P-chlorostyrene, 3,4-dichlorostyrene,
p-ethylstyrene, 2,4-dimethylstyrene, p-
n-butylstyrene, p-tert-butylstyrene,
Styrene and its derivatives such as p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene; ethylene, propylene, butylene, isobutylene ethylenically unsaturated monoolefins such as; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; methyl methacrylate, methacrylate Ethyl acid, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, methacrylic acid α-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid 2 - Acrylic esters such as ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl Vinyl ketones such as ketones;
N-vinyl compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinylnaphthalenes; vinyl monomers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; There is a mass.

Further, during polymerization of the monomer, a polymer, copolymer or cyclized rubber having a polar group is added as an additive to form a monomer.

In the present invention, during polymerization, a polymerizable monomer system containing a polar group-containing polymer, copolymer, or cyclized rubber is added to an aqueous phase in which a dispersant having a charge opposite to that of the polar polymer is dispersed. It is preferable to suspend and polymerize. That is, the cationic or anionic polymer, copolymer or cyclized rubber contained in the monomerizable monomer system is polymerized with the oppositely charged 7-ionic or cationic dispersant dispersed in the aqueous phase. Electrostatic attraction occurs on the surface of the particles that will become the toner during progress, and the dispersant covers the particle surface to prevent the particles from coalescing and stabilize them, and the polar polymer added during polymerization is the surface layer of the particles that becomes the toner. As the particles gather together, they form a kind of shell-like shape, and the resulting particles become pseudo-capsules. Using a relatively high molecular weight polar polymer, copolymer or cyclized rubber,
While giving toner particles excellent properties such as blocking properties, developability, and abrasion resistance, internal polymerization is carried out so that the molecular weight is relatively low and contributes to improving fixing properties, thereby eliminating the conflicting properties of fixing properties and blocking properties. It is possible to obtain a toner that satisfies these requirements.

Examples of polar polymers (including polar polymers) and counterloading dispersants that can be used in the present invention are shown below.

(a) Examples of cationic polymers include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl acrylate, or copolymers of nitrogen-containing monomers with styrene, unsaturated carboxylic acid esters, etc. .

(b) Examples of anionic polymers include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid, unsaturated dibasic acids, and unsaturated dibasic acids. Anhydrous.

There are polymers of nitro monomers.

(C) As the anionic dispersant, water-soluble polymers such as partially saponified vinyl acetate polymers or Aerosil #
There are colloidal silicas such as #200 and #300 (manufactured by Nippon Aerosil Co., Ltd.).

(d) Examples of the cationic dispersant include aluminum oxide, magnesium hydroxide, hydrophilic positively charged silica fine powder such as aminoalkyl-modified colloidal silica, and the like. Cyclized rubber may be used instead of the polar polymer.

During polymerization, polymerization is carried out in the presence of the following crosslinking agent,
It may also be a crosslinked polymer.

Divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene gelicol Dimethacrylate.

1, [3 Hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'bis(4-methacryloxyjethoxyphenyl)propane, 2.2'his(4- Acryloxyjetoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentyl glycol dimethacrylate, allyl phthalate, 1,2-propylene glycol, 1,3-butane Common crosslinking agents such as diols can be used as appropriate.

If these crosslinking agents are used in large amounts, they will not dissolve, resulting in poor fixing properties. In addition, if the amount used is too small, properties such as anti-blocking and durability required for toner will deteriorate, and during hot roll fixing, some of the toner will not completely adhere to the paper and will stick to the roller surface, causing the toner to be attached to the next paper. It becomes difficult to prevent the offset phenomenon of metastasis.

Therefore, the amount of these crosslinking agents used is 0.001 to 15% by weight (more preferably 0.1 to 10% by weight) based on the total amount of monomers.
It is best to use % by weight).

A charge control agent, a colorant, and a fluidity modifier may be added to the toner as necessary. Charge control agents and fluidity modifiers may be mixed (externally added) with toner particles.Charge control agents include metal-containing dyes, nigrosine, etc.1 Colorants include conventionally known dyes. , pigments can be used, and examples of fluidity modifiers include colloidal silica and fatty acid metal salts. In addition, fillers such as calcium carbonate and finely divided silica may be added to the toner in an amount of 0.5 to 20% by weight for the purpose of increasing the amount.Furthermore, it prevents mutual aggregation of toner particles and improves fluidity. For this purpose, a fluidity improver such as fine Teflon powder may be added. Furthermore, in order to improve the release properties during hot roll fixing, waxes that are generally used as release agents, such as hydrocarbon compounds and carnauba wax, may be added to the toner. This is because it is hydrophobic and has a low molecular weight.

After polymerization, the polymer crosslinked with the adhesive crosslinking agent is not mixed with the polymer, and compared to polar polymers, it is pushed into the inside of the toner instead of being exposed on the surface. During fixing, it comes out from inside, significantly improving fixing properties and offset properties. At that time, the hydrocarbon compound is considered to act as a solubilizer, a lubricant, and an oil.

The hydrocarbon compounds used in the present invention include paraffin and polyolefin having carbons of C6 or more, such as paraffin wax (manufactured by Nippon Oil), paraffin wax (manufactured by Nippon Seiro), microwax (manufactured by Nippon Oil),
Microcrystalline wax (manufactured by Nippon Seiro), P
E-130 (manufactured by Hoechst), Mitsui Hiwax ll0P
(manufactured by Mitsui Petrochemicals), Mitsui Hiwax 220P (manufactured by Mitsui Petrochemicals), Mitsui Hiwax 860P (manufactured by Mitsui Petrochemicals), and particularly preferred are low molecular weight polyethylene, low molecular weight polypropylene, and paraffin.

In the suspension method, a monomer system in which a polymerization initiator, colorant, monomer, additives, etc. are uniformly dissolved or dispersed is placed in an aqueous phase (i.e., a continuous phase) containing a suspension stabilizer. Disperse using an ordinary stirrer, homomixer, homogenizer, etc. Preferably, the stirring speed and time are adjusted so that the monomer droplets have the desired toner particle size, generally 30B or less, and thereafter the stirring is carried out so that this state is approximately maintained by the action of the dispersion stabilizer. It is only necessary to carry out this process to the extent that sedimentation of the particles is prevented. The polymerization temperature is set at 50°C or higher, generally from 70 to 80°C. After the reaction is completed, the produced toner particles are recovered and dried by a suitable method such as washing, filtration, decantation, centrifugation, etc. concern
In the II4 polymerization method, 300 to 3.000 parts by weight of water is usually used as a dispersion medium per 100 parts by weight of monomer.

Suitable dispersion media used in the present invention include, for example, any suitable stabilizer such as polyvinyl alcohol,
Gelatin, methyl cellulose, methyl hydropropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and their salts, starch, gum alginate, zein, casein,
An aqueous phase containing one or a mixture of tricalcium phosphate, talc, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, titanium hydroxide, thorium hydroxide, etc. can be used. The stabilizer is used in a stabilizing amount in the continuous phase, preferably within the range of about 0.1 to 10% by weight. Additionally, a surfactant in the range of 0.001 to 0.1% by weight may be used for fine dispersion of the inorganic dispersant, which promotes the intended action of the dispersion stabilizer. Specific examples include sodium dodecylbenzenesulfonate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, sodium allyl-alkyl-polyethersulfonate, sodium oleate,
Sodium laurate, sodium caprate, sodium caprylate, sodium capron, potassium stearate, calcium oleate, 3,3-disulfonodiphenylurea-4,4-diazo-bis-amino-8-
Sodium naphthol-6-sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2.2,5
．． Examples include sodium 5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-disulfone, and others.

In addition, monomers that are easily soluble in water simultaneously cause emulsion polymerization in water, and the resulting suspension polymer is contaminated with small emulsion polymer particles. It is also good to add glycerin, glycol, etc. to water to prevent emulsion polymerization, and to prevent coalescence of particles by increasing the viscosity of the medium. In addition, NaCR, KCR, Na2SO
It is also possible to use salts such as No. 4.

[Examples] Hereinafter, the present invention will be described in detail based on Examples. In addition, the number of parts in the following examples is parts by weight.

Example 1 The monomer composition described above was dispersed for 30 minutes using a sand mill while maintaining the temperature at 70°C, and a magnetic substance was processed.

Next, the above monomer composition was taken out, and 10 g of benzoyl peroxide was dissolved therein.

On the other hand, 10 g of aminoalkylsilane-treated silica was dispersed in the water prepared in step 1.2 and placed in a 2ρ container.
The mixture was heated to 0.degree. C., and the above monomer composition was added thereto. This was mixed using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).
．． The suspension was granulated by stirring at 000 rpm. The resulting suspension was transferred to a reaction vessel, and the temperature was maintained at 85° C. for 15 hours under stirring to complete polymerization. Volume average particle size 11
．． 4 gm of toner was obtained. The particle size distribution is 6% in number distribution, 13°6% in 35gm or less, and 20.2 in volume distribution.
1zm or more is 2.8% (Coulter counter, 100
gm aperture). To 100 parts of toner, 0.4 part of Tallanox 500 (manufactured by Talco) was added to form a developer.

When this developer was put into a copying machine NP-270RH manufactured by Canon Co., Ltd. and an image was produced, the image was good, and the offset and fixing properties were also good. Further, no deterioration in image quality or density was observed in a 3,000-sheet image reproduction durability test.

Example 2 Titanium coupling agent KR-138S (manufactured by Ajinomoto Co., Ltd.)
A polymerized toner was obtained in the same manner as in Example 1, except that magnetic material BL-200 (manufactured by Titan Kogyo Co., Ltd.) which had been hydrophobized using 2 parts of the magnetic material was used.

The volume average particle size t+ of this toner is 3g, 12.7% of particles are 8.35B or less in number distribution, and 20.2% in volume distribution.
The ratio of µm or more was 2.4%.

When the image was printed in the same manner as in Example 1, the image was good, and the offset and fixing properties were also good. Also, 3
Even in a durability test of ,000 sheets, no deterioration in image quality or density was observed.

Example 3 A polymerized toner was obtained in the same manner as in Example 1 except that di(2-ethylhexylperoxy) dicarponate was used instead of diisobutyryl peroxide in the magnetic material treatment step.

The volume average particle diameter of this toner was 11.9 pm+, and the number distribution was 10.8% for 8.35p+a or less, and 0.7% for 20.2μ layers or more.

When image printing was carried out in the same manner as in Example 1, a good image was obtained, and both off', torability and fixing properties were good. In addition, no deterioration in image quality was observed in the 3,000-sheet durability test, and there was only a slight change in density. The magnetic material was processed.

Next, the above monomer composition was taken out, and 12 g of dilauroyl peroxide was dissolved therein.

On the other hand, 4 g of 7Erosil 200 (manufactured by Nippon Aerosil) was dispersed in 1.22% water in advance, placed in a 2I2 container, heated to 70°C, and the above monomer composition was added. This was mixed at 7.30O using the mixing device used in Example 1.
Stir for 20 minutes at rpm. The obtained suspension was transferred to a reaction vessel and reacted under stirring at 75°C for 24 hours to complete polymerization.The zero volume average particle diameter was 11.7 gm, and the number distribution was 8.35 pm or less, 13.1%. The volume distribution was 20.2 cm or more and 2.1%.

100g of this toner with Nibsil ER (manufactured by Nippon Silica)
0.4 g was added to prepare a developer. Commercially available copy machine PC-
20 (manufactured by Canon) to produce an image,
The image was good, and the offset and fixing properties were also good. Further, no deterioration in image quality or density was observed in a durability test of 3,000 sheets.

Example 5 In Example 4, t-butylperoxyneodecanoate was used instead of dilauroyl peroxide, and the temperature at 60°C
A polymerized toner was obtained in the same manner except that the polymerization was carried out.

Comparative Example 1 Polymerization was carried out in exactly the same manner as in Example 2, except that the step of dispersing the magnetic material using diisobutyryl peroxide was omitted.

The obtained polymer was dispersed in water as in Example 1.
Similarly, no aggregates were present and the product was stable.

However, when the dispersion stabilizer was removed in order to take it out of water, the toner particles fused together and could no longer be dispersed into individual particles.

Comparative Example 2 Polymerization was carried out in the same manner as Comparative Example 2 except that 10 g of benzoyl peroxide and 6.8 g of diisobutyryl peroxide were used together.

The obtained polymerized toner had a volume average particle diameter of 12.2 gm, 28.2% had a number distribution of 8.35 pm or less, and 13.5% had a volume distribution of 20.2 μm or more.

It was observed that there were aggregates of magnetic particles in the obtained toner particles and they were not uniformly dispersed, and the distribution was broad, so classification was performed to obtain a toner having the same distribution as in Example 1. .

When this toner was subjected to image printing in the same manner as in Example 1, in the durability test, offset occurred after about 100 sheets of self-spraying, and the deterioration of the self-sprayed image quality became severe around the 200th sheet, so the test was discontinued.

Comparative Example 3 Polymerization was carried out in exactly the same manner as in Example 6, except that the step of dispersing the magnetic material using di(cyclohexylperoxy) dicarponate was omitted.

The volume average particle diameter of the obtained toner was 13.7B, the number distribution was 6.35 μm or less at 23.1%, and the volume distribution was 20.
14.1% had two or more terminal intestines.

Aggregates of magnetic particles were observed in the obtained toner particles, and the particle size distribution was also broad. When the particle size distribution was determined to be the same as that of the toner of Example 3 by 0 classification, and image printing was performed. The image has a low density, and in the durability test it was about 2.00 (deterioration in image quality and density was seen in one self-propelled image).

Table 1 shows the image density in Examples 1 to 5 and Comparative Examples 1 to 3 and the evaluation under high humidity conditions.

[Effects of the Invention] As described above, according to the present invention, a polymerized toner with a narrow particle size distribution can be obtained, and good image quality, offset properties, fixing properties, and durability can be obtained.

Claims (1)

[Claims] (1) A method for producing toner by dispersing a monomer composition containing at least a polymerizable monomer and a magnetic material in an aqueous phase containing a dispersant, and carrying out suspension polymerization, the method comprising: A method for producing a polymerized toner, comprising using a magnetic material whose surface is treated with a peroxide-based polymerization initiator.