JPS63271467A - Production of toner for electrophotography - Google Patents

Abstract

PURPOSE:To improve the durability, electrostatic charge stability and cleanability of a toner by emulsion-polymerizing a specified phthalimide monomer and other polymerizable monomer and subjecting the resulting polymer emulsion to salting out and heat treatment. CONSTITUTION:10-60wt.% phthalimide monomer represented by the formula (where R1 is H or methyl and R2 is 1-6C alkylene) and 90-40wt.% other polymerizable monomer such as styrene are used as starting materials for resin for a toner. The monomers and a colorant and/or magnetic powder are dispersed in an aq. medium contg. an emulsifier and the monomers are polymerized. The resulting polymer emulsion is subjected to salting out so as to obtain a particle size distribution suitable for a toner and it is heat treated at the glass transition point of the resin component or above, washed and dried to produce a toner. This toner has superior durability, electrostatic charge stability, cleanability and resistance to blocking and contamination by vinyl chloride.

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.

An electrostatic latent image based on the original image is formed on the photoreceptor.

Thereafter, the image is visualized using a developer containing toner.

This visualized toner image is generally .

The image is transferred to a suitable transfer member and fixed 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 body. 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 carrier and toner;
The latter consists only of toner. Toner, which is necessary to develop the electrostatic charge image on the photoreceptor, uses toner of opposite polarity to the electrostatic charge image.
A two-component developer is one that uses frictional electrification between the carrier and toner.

On the other hand, 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 prepared by melting and kneading a colorant such as a carbon blank and/or a magnetic powder such as magnetite in a thermoplastic resin to form a dispersion, and then appropriately pulverizing the mixture. Toners have been produced by mechanically applying impact force to a device to pulverize the dispersion to a desired particle size, and if necessary, further classifying it to form a toner. The 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 using a resin that is desirable for the melt mixing process and the crushing process9. Furthermore, if a resin that is easily crushed is used, it will be crushed into fine toner particles in the developing machine, resulting in image fogging and dirt inside the machine.

In addition, the colorant dispersed in the resin appears on the surface of the pulverized toner, which may cause a decrease in the amount of triboelectric charge in high humidity conditions or drop-off of the colorant in the developing machine. This causes undesirable development such as contamination of the carrier surface and contamination of the photoreceptor surface.

In order to solve these drawbacks of the pulverization method,
Japanese Patent No. 10799 proposes a method for producing completely spherical toner particles by spray drying an emulsion obtained by emulsion polymerization.

! It was. In order to solve the drawbacks of the pulverization method, toner manufacturing methods using a suspension polymerization method have been proposed in Japanese Patent Publication No. 14895/1982 and Japanese Patent Application Laid-open No. 53756/1989, etc. ing. When using the suspension polymerization method, a perfectly spherical toner can be obtained.

(Problems to be Solved by the Invention) Conventionally, toners obtained using such a polymerization method are
Although some of the drawbacks of the nine toners obtained by the grinding method have been solved, it has been found that new drawbacks arise. In other words, if the emulsifier or suspending agent remains in the toner particles, the charging stability and blocking resistance will deteriorate. It was.

Since the obtained toner particles are perfectly spherical, the cleaning properties are poor.

On the other hand, when producing a toner by emulsion polymerization.

It is also possible to salt out the emulsion polymerization solution to collect particles and pulverize them to an appropriate particle size, but this method has the disadvantage that the durability and moisture resistance of the resulting toner are significantly reduced. .

Furthermore, the charge control agent that is usually added to adjust the chargeability of toner impairs the stability of ionic emulsion polymerization, lowers the toner yield, and in some cases causes the polymerization system to become sticky during emulsion polymerization. to become

They also reduce toner fluidity, adhere to carriers and degrade their properties, and adhere to electrostatic image supports and contaminate them.

In addition, recently, a method of storing paper that has been developed and copied using toner by sandwiching it between sheets of vinyl chloride resin has been widely used, but since 9M resin inevitably contains a plasticizer, Conventionally well-known toners, for example,
It has been found that there is a problem in that the toner containing polystyrene, styrene-methacrylic acid ester copolymer, etc. as the main resin component softens and the image fixed on the paper is transferred to the sheet. This is a copy of the paper.

This is a problem that can occur even if the cable is in contact with an electric wire cord coated with vinyl chloride resin for a long time. These problems are explained below.
It is called PVC contamination.

゛The present invention solves nine or more problems.

That is, it solves the problems in the conventional toner manufacturing method and has excellent image performance, resolution, moisture resistance, non-offset property, and gradation, as well as IP! to j.

An electrophotographic toner suitable for dry development that has excellent durability, cleanability, charge stability, and blocking resistance can be produced in high yield, and the obtained toner has excellent resistance to PVC staining. A method of manufacturing a certain toner is provided.

(Means for Solving the Problems) The present invention provides (A) general formula (I): [wherein R1 represents hydrogen or a methyl group, and R3 has 1 carbon number]
10 to 60% by weight of a phthalimide monomer represented by [representing an alamda kylene group of ~6] and (B) 70 and others +7) polymerizable monomer 90 to 4011
The emulsion polymerization solution obtained by emulsion polymerization in the presence of a colorant and/or magnetic powder was mixed so that the total i%ft was 100% by weight, and was salted out to obtain a particle size suitable for a toner. The present invention also relates to a method for producing an electrophotographic toner, which is characterized by heat treatment at a temperature equal to or higher than the glass transition point of the main resin component.

The emulsion polymerization of the polymerizable monomer in the present invention is carried out in an aqueous medium containing an emulsifier! i) This is carried out by emulsifying and dispersing a polymerizable monomer and polymerizing it.

During this emulsion polymerization, a coloring agent and/or magnetic powder and a polymerization initiator can be added. In addition, toner property improvers such as fluidity improvers, cleaning performance improvers, and offset inhibitors, stabilizers that aid in emulsification and dispersion, and chain transfer agents may be added as appropriate.

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.

A polymerization initiator may be added during the emulsion dispersion, but
It is preferable to dissolve the water-soluble polymerization initiator in advance in an aqueous medium during emulsification and dispersion. Moreover, as the monopolymerization initiator, an oil-soluble polymerization initiator can also be used, and it is preferable to dissolve this in advance in the monopolymerizable monomer. It is also possible to use a water-soluble polymerization initiator and an oil-soluble polymerization initiator together.

Further, in order to improve dispersion in the resin, the colorant and/or magnetic powder (9) is preferably used after being dissolved or dispersed in the polymerizable monomer in advance, even though it is added after the emulsification and dispersion described above. The same applies to various toner property improvers used as needed. Furthermore.

Stabilizers can be used as needed, but this...

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 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, if necessary, a toner property improver are dispersed in a monopolymerizable monolayer.

The emulsion polymerization is preferably carried out at a temperature of 20 to 120° C. after or while emulsifying and dispersing the emulsion.
Preferably it is carried out at a temperature of ~80°C.

This emulsion polymerization is preferably carried out until the polymerization rate reaches 99% by weight or more, particularly preferably 99.9% by weight or more. Polymerization rate is low.

When the amount of residual monomer increases, the storage stability of the toner tends to be inferior to 1%.

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 low, 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 9% and 50 to 80°C. If the glass transition point is too low.

If it is too high, blocking resistance tends to decrease.

Stability tends to decrease. The glass transition point can be adjusted mainly by selecting the polymerizable monomer to be used.

Such emulsion polymerization yields particles of about 3 μm or less.

Next, one material used in the present invention will be explained.

The phthalimide monomer represented by the general formula (1) which is the component (3) is 9, for example, phthalimidomethyl acrylate or methacrylate, phthalimidoethyl acrylate or methacrylate.

These include phthalimidopropyl acrylate or methacrylate, phthalimidobutyl acrylate or methacrylate, and the like.

The amount of this phthalimide monomer is 10% based on the total amount of monomers.
~60% by weight, preferably 20-50% by weight. If this amount is less than 10]1f, the amount is less than 1f.

The effect of the present invention is small and the toner is not suitable for practical use.

On the other hand, if it exceeds 60 wt-i%, the properties of the toner deteriorate and are not practical.

Other polymerizable monomers as component (B) include:

Styrene, 0-methylstyrene, m-methylstyrene,
p-methylstyrene, p-ethylstyrene.

2.4-dimethylstyrene, p-n-butylstyrene,
p-tert-butylstyrene, p-n-hexylstyrene, p-,n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene.

p-n-dodecylstyrene, n-methoxystyrene, p
-Phenylstyrene, p-/rorostyrene.

Styrene and styrene O conductors such as 44-dichlorostyrene, ethylenically unsaturated monoolefins such as ethylene, fluoropylene, butylene, and imbutylene, vinyl chloride, vinylidene chloride, and vinyl bromide.

Vinyl halides such as vinyl fluoride, vinyl acetate.

Vinyl esters such as vinyl propionate, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid 2 -Ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate.

α-Methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate.

α-methylene such as n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylamine ethyl acrylate, dimethylaminoethyl methacrylate, etc. Derivatives of acrylic acid or methacrylic acid such as aliphatic sonocarboxylic acid esters acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc., optionally is 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 isopropenyl ketone; N-vinyl compounds such as vinylpyrrolidone, vinylnaphthalene salts, etc. can be used singly or in combination of two or more. Among these polymerizable monomers, styrene or styrene derivatives are preferably used in an amount of 40% based on the total amount of polymerizable monomers.
When used in an amount of up to 90% by weight, the toner has excellent fixing properties when copied onto paper using an electrophotographic copying device.

1 & As the polymerizable monomer of the present invention, a compound having t-2 or more polymerizable double bonds that can serve as a crosslinking agent can also be used. For example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof, diethylene carboxylic acid esters such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol triacrylate, trimethylolpropane triacrylate, N,N-
All divinyl compounds such as divinyl aniline, divinyl ether, and sulfinyl sulfite and compounds having three or more vinyl groups can be used alone or as a mixture. The amount of crosslinking agent used is 0 to 9 based on the total amount of polymerizable monomers.
It is preferably 20 weights, particularly preferably 0 to 5 weights.

The aqueous medium used in emulsion polymerization is primarily water. The ratio of the polymerizable monomer to the aqueous medium is preferably 60/40 to 10/90 in weight ratio of the former/latter. If this ratio is too large, emulsion polymerization will be difficult, and if this ratio is too small, 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, it is preferable to use a nonionic surfactant in combination to improve dispersion stability.

Examples of anionic surfactants include fatty acid salts such as sodium oleate and potassium mustard oil, alkyl sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfonic acids. salt, dialkyl sulfosuccinate, alkyl phosphate ester salt, naphthalene sulfonic acid formalin m compound,
Examples include polyoxyethylene alkyl sulfate salts.

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- Examples include oxypropylene block polymers.

Examples of cationic surfactants 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.

In the present invention, it is preferable to use a cationic surfactant or a combination of a cationic surfactant and a nonionic surfactant.

The amount of emulsifier used is 0.0 based on the total amount of monopolymerizable monomers.
It is preferably 1 to 10% by weight, and preferably 0.5 to 5% by weight. If the amount of emulsifier used is too small, stable emulsion polymerization becomes difficult, and if it is too large, the resulting toner tends to have poor moisture resistance.

Stabilizers include polyvinyl alcohol, starch,
Water bathable polymeric substances such as methylcellulose, carboxymethylcellulose, and hydroxyethylcellulose are used.
It is preferable to use these in an amount of 0 to 1 weight per hexapolymerizable monomer.

The water-soluble polymerization initiator used in the present invention includes:

For example, persulfates such as potassium persulfate and anthonium persulfate, hydrogen peroxide, 44'-azobiscyanovaleric acid, 42
'-azobis(2-amidinopropane) dihydrochloride, t-
Butyl hydroperoxide, cumene hydroperoxide, etc. can be used.

The amount used is 0.01 to 10% by weight based on 9 polymerizable monomers.
The content is preferably 0.1 to 5% by weight, particularly preferably 0.1 to 5% by weight. Too little polymerization initiator.

The polymerizable monomer is not completely polymerized, and there is a tendency for the characteristics of the residual toner to deteriorate.

As a polymerization initiator, benzoyl peroxide, perbenzoic acid t
Oil-soluble polymerization initiators such as peroxides such as ert-butyl and azo compounds such as azobisisobutyronitrile and azobisisobutylvaleronitrile can also be used.

The water-soluble polymerization initiator described above may be used in combination with a reducing agent. As the reducing agent, commonly known ones such as metabisulfite, ferrous chloride, etc. can be used. Although it is not necessary to use a reducing agent, tl! When used, it is preferably used in an amount equal to or less than the amount of 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. It is preferable to do so.

Colorants preferably used in the present invention include:

For example, ai carbon black, grafted carbon black, lamp blank (C, I, Na77266
).

Chrome yellow (C, 1, Nal 4090),
Rose Bengal (C, 1, & 45435) etc. can be used alone or in combination.

Among these colorants, one particularly preferred for the toner of the present invention is alkaline carbon black, such as furnace black, channel black, thermal black, acetylene black, lamp black, grafted carbon black, and the like. Furthermore, the carbon blank may be subjected to surface treatment. One example of surface treatment is oxygen.

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

Also, what is the above-mentioned grafted carbon black?

It is obtained by multiple polymerizing the above polymerizable monomers by bulk polymerization, solution polymerization, etc. in the presence of carbon black. The polymer component of the grafted carbon black is preferably 50% by weight or less, particularly preferably 301Ki 1% or less, based on the grafted carbon black. Grafted carbon black is preferable because it has excellent dispersion stability during emulsification.
If the polymer acid content is too large, the viscosity tends to be too high when dispersed in monopolymerizable monomers, and workability is reduced. What is the amount of grafted carbon black used?

It is preferable to determine the amount of carbon black component.

These colorants can be used in any amount, but
Preferably from about 1 to 30% by weight in the toner to obtain the required concentration and for economic reasons.

Particularly preferably, they are used in a ratio of 5 to 15 times.

In the present invention, in addition to the above-mentioned colorants, for example, nigrosine dye N (C, 1, Na50415), aniline blue (
C,1,Na5.0405), Calco Oil Blue (C,I.

Nnazoec Blue 3), DuPont Oil Red (C, I.

Na26105), Orient Oil Red◆330(
C, I, Na60505), quinoline yellow (C, I
, Nα47005), methylene blue chloride (C,
1, Na52015), 7 talocyanine pur (C, i
, Na 74160).

Malachite green offsalate (C, I, Na420
Organic dyes such as 00) can also be used.

Magnetic powder is used when manufacturing magnetic toners, and it can also serve as a colorant. Preferred magnetic powders include oxides or compounds of elements exhibiting ferromagnetism, such as iron, nickel, and cobalt, such as magnetite or ferrite. These magnetic powders have a particle size of 0
．． A powder having a diameter of 0.01 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 powders are preferably used in an amount of 20 to 80% by weight, particularly preferably 35 to 7omits, based on the total toner components.
It can be included. 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 the form of a substance at the time of polymerization, and can be included in the toner product.

Alternatively, the anti-offset agent can be added later to the toner of the present invention in which it is not present. As the anti-offset agent, one of various natural waxes such as carnauba wax, hydrogenated castor oil, low molecular weight olefin polymers, etc. can be used in the present invention, and preferably low molecular weight olefin polymers are used. This low molecular weight olefin polymer is
An olefin polymer or a copolymer of an olefin and a monomer other than olefin with a low molecular weight is used. Here, olefins include ethylene, propylene, butene-1, etc., and monomers other than olefins include acrylic esters.

There are methacrylic acid esters, etc. Examples of this low molecular weight olefin polymer include 1, for example, JP-A-55-153944;
The polyalkylene described in the publication, JP-A-50-
Low molecular weight olefin copolymers described in Japanese Patent No. 93647 can be used.

In the present invention, the low molecular weight olefin polymer may be one that is included in the concept of low molecular weight in ordinary polymer chemistry, and generally has a weight average molecular weight (Mw) of 100.
0~45000. Preferably it is 2000-6000.

The low molecular weight polyolefin polymer used in the present invention is i
It is preferable to have a softening point of oo to 180°C, particularly 130 to 160°C.

The amount of the low molecular weight olefin polymer that can be used in the present invention is not particularly limited, but is preferably in the range of 0 to 30 weights and 11 inches based on the weight of the toner. If the amount of low molecular weight polyolefin exceeds 30% by weight, gelation may occur during one polymerization reaction.

Furthermore, fluidity improvers, cleaning performance improvers, etc. can be used as necessary. these are.

Although it can be present in the polymerization reaction system and present in the product toner, it is preferably externally added to the product toner afterward. It is preferable that the content of each of these is 0 to 3% by weight based on the toner of the present invention. Fluidity improvers include
Cleaning property improvers include oxides of silane, titanium, aluminum, calcium, magnesium, and magnesium, or those obtained by hydrophobicizing the oxides with a titanium coupling agent or a silane coupling agent.

These include metal salts of higher fatty acids such as zinc stearate, lithium stearate and magnesium laurate, or aromatic acid esters such as pentaerythritol benzoate.

In the present invention, since the monomer represented by general formula (1) imparts chargeability, there is no need to use a charge control agent.
Furthermore, it may be used to adjust charging properties.

Dibutyltin oxide is used as a charge control agent.

Tin compounds such as dioctyltin oxide, the above-mentioned organic dyes, etc. are used in an amount that is less than half of the amount used in normal toners, that is, 0 to 25% by weight based on the total toner components.
is preferred.

In the method of the present invention, after the main resin component is produced by emulsion polymerization, a salting out agent is added to the obtained emulsion polymerization solution to perform salting out. As a result, the particles in the emulsion polymerization liquid are appropriately agglomerated, and the resin has a larger average particle size than the particles in the emulsion polymerization liquid, is imperfectly spherical, and is suitable for toners that do not require pulverization. particles can be obtained.

Here, it is preferable to adjust the particle size distribution of the aggregated particles to 1 to 100 μm, particularly preferably to adjust 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. It is preferable to adjust the average particle size to 9 to 15 μm. For the above adjustment, it is preferable to use the salting-out agent in an amount of 0.1 to 5 times, preferably 0.3 to 3 times, the weight of the emulsifier in the emulsion polymerization solution. If the amount of salting-out agent used is too small.

If the salting-out effect is insufficient, and if the amount is too high, the moisture resistance of the toner will be poor and the average particle size of the particles will be too large.

This salting-out step yields toner particles that are completely spherical, resulting in toner particles that have excellent cleaning properties. In addition, since the emulsifier is also removed by the salting out process, 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 adding the emulsion polymerization liquid little by little to 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.

Further, after salting out, it is necessary to heat the particles to a temperature higher than the glass transition point of the main resin component of the particles (hereinafter, this treatment is referred to as "heat treatment").

By this heat treatment, the bulk density of each particle is large, and the moisture resistance and durability are improved most. The upper limit of the heat treatment temperature is preferably 150°C. If this temperature is too high,
Not only is the main resin component more likely to deteriorate, but the heating equipment becomes complicated. Furthermore, when the heat treatment temperature becomes higher, the shape of the toner becomes spherical, resulting in poor cleaning performance.

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 chloride, aluminum sulfate, barium chloride, magnesium chloride, calcium chloride, sodium chloride, and/or combinations of these with inorganic acids. It is preferable to use these salting-out agents as a 0.1 to 10% by weight aqueous solution, particularly a 0.1 to 4% by weight aqueous solution.

The particles obtained through the salting out step (and heat treatment step) are in the form of a slurry, which can be centrifugally dehydrated to isolate the particles, which are further washed and dried.1. Further, if necessary, the toner is classified into electrophotographic toners.

In particular, washing does not only remove the emulsifier adhering to the toner, but also contributes to improving the charging stability and blocking resistance of the toner obtained in the above-mentioned salting-out step. .

Washing is preferably carried out with warm water at 40 to 70°C;
It may be lower than 0°C.

The toner obtained according to the present invention can be used in various development processes.
For example, the cascade development method described in U.S. Pat. No. 2,618,552, U.S. Pat.
Magnetic brush method as described in US Pat. No. 65, Powder cloud method as described in US Pat. No. 2,221,776, Touch as described in US Pat. Down development method 9% 1976-
The so-called jumping method described in Japanese Patent No. 18656, the so-called microtoning method in which the necessary toner charge is obtained by using a pulverization method as a carrier, and the so-called bipolar method in which the necessary toner charge is obtained by frictional charging between magnetic toners.
It can be used in magnetic toner methods, etc.

Furthermore, the toner obtained according to the present invention can be used in various fixing methods such as so-called oil-less and oil-coated heat roll methods, flash methods, open methods, pressure fixing methods, and the like.

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

(effect) In the present invention, the emulsion polymerization solution is salted out.

It is possible to appropriately agglomerate the particles in the emulsion polymerization liquid to obtain resin particles suitable for toner that have a larger average particle diameter than the particles in the emulsion polymerization liquid, are imperfectly spherical, and do not require pulverization. can.

Since incompletely spherical toner particles are obtained through this salting-out process, the toner has excellent cleaning properties, and since the emulsifier is also removed during the salting-out process, blocking resistance and charging stability are improved. Sexuality is also improved.

In the present invention, since the phthalimide monomer represented by the general formula (1) is used as a copolymerized component as an essential component, the toner has excellent resistance to vinyl chloride staining, and the toner has good durability and moisture resistance. Further, since stable emulsion polymerization can be performed by the action of the phthalimide monomer represented by the general formula (1), the toner yield is high and the polymerization system does not become cake-like during emulsion polymerization.

Furthermore, since the main resin containing the phthalimide monomer represented by general formula (1) has chargeability, it is possible to impart chargeability to the toner without using a charge control agent. can. Even if a charge control agent is added to further adjust the chargeability, the amount required is less than half of that of conventional toners, so the emulsion polymerization is sufficiently stabilized by the action of the phthalimide monomer, and the toner can be produced in high yield. Obtainable.

As described above, according to the present invention, the amount of the charge control agent used can be completely eliminated or reduced by using the phthalimide monomer, thereby reducing the fluidity of the toner and the adhesion of the charge control agent to the carrier. Other adverse effects caused by the use of charge control agents, such as toner adhesion to electrostatic image supports, can also be eliminated or reduced.

(Example) Next, one embodiment of the present invention will be explained based on an example.

The present invention is not limited to this. In the examples, “
"CH" means "% by weight" unless otherwise specified.

Example 1 (1) Production of emulsion polymerization solution 51! Phthalimide ethyl methacrylate 3009. as a graphing monomer as a coloring agent in a stainless steel beaker.
450 g of styrene, 250 g of butyl acrylate, and 2 g of t-dodecylmercaptan as a chain transfer agent were mixed and dispersed using a homomixer at 300 Orpm for 30 minutes.

Next, stearyltrimethylammonium chloride 509 (Kotaon 86P Conc manufactured by Kao ■, endowed ingredient 63%) 509, which is a cationic surfactant, is added to ion-exchanged water 20009 as an emulsifier, and 42'-azobis(2-amidinopropane) dihydrochloric acid is added as a polymerization initiator. An aqueous solution in which Salt 509 was dissolved was added to this dispersion, and the mixture was further dispersed for 30 minutes using a homomixer.

A black pre-emulsion was obtained.

Next, the black pre-emulsion was transferred to a 41!4 rosette flask equipped with a stirrer, nitrogen inlet, thermometer and condenser, polymerized at 70°C for 5 hours under a nitrogen gas stream, and then cooled. An emulsion polymerization solution was obtained. The polymerization rate at this time was 99.9 or more. The molecular weight of the polymer was measured by gel permeation chromatography using a standard polystyrene calibration curve.

Weight average molecular weight (Mw) 84000. Number average molecular weight (M
n) It was 33,000.

(2) Salting out step, final step Emulsion polymerization solution 11! 0.3%M heated to 50℃
gSO4 aqueous solution 2I! While stirring thoroughly and maintaining the temperature of the aqueous solution at 50°C, drop it uniformly over about 30 minutes.
It was salted out. The mixture was kept at this temperature for an additional 30 minutes, and then cooled to room temperature.

Next is this slurry II! Transfer to autoclave for 30 minutes.
The temperature was maintained at 120° C. for minutes. Cool this slurry and
After dehydration using a centrifugal dehydrator, the edges were washed three times with warm water at 50°C.

Then, the toner was dried at 30 to 35[deg.] C. in a dryer in step 11i, and the particle size of the obtained toner was measured using a Coulter counter, and the particle size was 2 to 90 [mu]m, and the average particle size was 20 [mu]m. Further, the glass transition point (Tg) was measured using a differential scanning calorimeter and was found to be 69°C.

This toner was further classified into 5 to 25 μm using a zigzag classifier (100MZR Alvin Co., Ltd.), and the yield was 85 μm compared to that before classification.

In addition, in the following Examples and Comparative Examples, the 9 particle diameter and the average particle diameter were measured using a Coulter counter, the glass transition point was measured using a differential scanning calorimeter, and the 1 classification was measured using a zigzag classifier.

Example 2 (1) Production of emulsion polymerization solution In the same manner as in Example 1, grafted carpump 1=)≠
1676m Phthalimidoethyl methacrylate 5009
．． Styrene 2509. Butyl acrylate 250ge
2 g of t-dodecyl mercaptan and 109 g of low molecular weight polypropylene (manufactured by Sanyo Kasei Kogyo ■, trade name: Viscol 660P) as an offset inhibitor were mixed in a homomixer for 300 g.
Mixing and dispersion was performed using Orpm for 30 minutes.

Next, 200g of ion-exchanged water was mixed with Cortamino 86P Conc 509. Noniball PE with nonionic surfactant
-68 (manufactured by Sanyo Kasei Kogyo ■, trade name) 10g and 42'-azobis(2-amidinopropane) as a polymerization initiator.
Adding an aqueous solution in which 50 g of dihydrochloride was dissolved to the dispersion,
Dispersion was further performed for 30 minutes at 3000 rpm to obtain a black pre-emulsion.

This black pre-emulsion is 41! The mixture was transferred to a parallel flask and polymerized at 70° C. for 5 hours under a nitrogen gas stream, and then cooled to obtain an emulsion polymerization solution.

The polymerization rate at this time was 99.9% or more, Example 1
The molecular weight of the polymer obtained in the same manner as is Mw9500
0, Mn 38,000.

(2) Salting out step, final step Emulsion polymerization solution 11! 0.3% heated to 40'C
Mg80a aqueous solution 2I! While sufficiently stirring the aqueous solution and keeping the temperature of the aqueous solution at 40 to 45° C., the solution was added dropwise uniformly over about 30 minutes to effect salting out. Keep warm for another 30 minutes.

Cooled to room temperature. Next is this Sura IJ-1l! Transfer to an autoclave and keep heated at 110°C for 30 minutes.

The obtained slurry was washed and dried in the same manner as in Example 1. The obtained toner had a particle size of 1 to 70 μm.

The average particle size was 18 μm. Furthermore, the glass transition point was measured and found to be 70°C. When this toner was further classified into 5 to 25 μm using a zigzag classifier, the yield was 88% of that before 9 classification.

Example 3 Emulsion polymerization liquid and toner with a polymerization rate of 99.9 cm or more were prepared in the same manner as in Example 2, except that 167 g of the grafted carbon in Example 2 was replaced with 50 g of Carbon Blacker 44 (manufactured by Mitsubishi Chemical Industries, Ltd.). Obtained. The molecular weight of the polymer is Mw 9.1 (
000, Mn 41000. The toner yield is 8
2%, and the glass transition point (Tg) was 72°C.

Comparative Example 1 The same procedure as in Example 1 was carried out except that phthalimidoethyl methacrylate in Example 1 was replaced with styrene, but the polymerization rate was 99.
An emulsion polymerization solution and toner having a concentration of 9% or more were obtained. The weight average molecular weight (Mw) of the polymer is 93000° and the number average molecular weight (Mn
) was 36,000, the toner yield was 90%, and the glass transition point (Tg) was 73°C.

Comparative Example 2 Styrene was substituted for 7-thallimidoethyl methacrylate in Example 1, and a nigrosine derivative (
An emulsion polymerization solution and toner with a polymerization rate of 98% were obtained in the same manner as in Example 1, except that 20 g of Oil Black BY Orient Chemical ■H) was added during dispersion of the graft carbon. The weight average molecular weight (Mw) of the polymer is 104,000.
The number average molecular weight (Mn) was 4400'0, the toner yield was 60°C, and the glass transition point (Tg) was 67°C.

Testing of Toner Properties Using the classified toners obtained in Examples 1 to 3 and Comparative Examples 1 to 2, electrophotography was performed using a plain paper copying machine (manufactured by Sharp ■, 5F755) using a commercially available insulating carrier. Toner properties were tested. However, each toner contains 0.1% each of hydrophobic silica (manufactured by Nippon Aerosil ■, R-972) and zinc stearate as fluidity improvers.
External addition treatment was performed. The test results are shown in Table 1.

Evaluation of electrophotographic properties The electrophotographic properties were evaluated as follows.

(a) Charge amount: Each of the prepared developers was stirred in a copying machine for 10 minutes, and the charge amount was measured using a blow-off powder charge amount measuring device (manufactured by Toshiba Chemical N).

(b) Resolution: Electrophotography Society Test Chart Nal
Copies were made on plain paper using the respective developers. Compare and evaluate whether the copied images can be read in detail.9.

(C) Image density: The density of the black portion of the copied paper was measured using a Macbeth densitometer in the same manner as the resolution and was evaluated as 9.

(dl Gradation: Evaluated in the same way as the resolution using the a-dark area divided into 11 levels in the center of the test chart.

(e) Cleanability: Each of the prepared developers was continuously copied using a copying machine at a temperature of 30° C. and a relative humidity of 80%, and evaluated by the number of copies until cleaning failure occurred.

(f) Blocking resistance: Examples 1 to 2. Comparative example 1
Toner prepared in ~2 to 7 at 50℃ and 95% humidity.
After being left for 2 hours, it was determined whether or not the toner had blocked, and evaluation was made based on the following criteria.

◎: Excellent O: Excellent △: Slightly inferior ×: Inferior (g) Charge stability: Stir the prepared developer in a copying machine, measure the amount of charge at regular intervals, and check the amount of charge. It was judged based on the change in , and evaluated using the following criteria.

◎: Very good ○: Excellent △: Slightly inferior ×: Inferior.

(h) Durability: Using a copying machine, each of the prepared developers was used to continuously copy 7,000 sheets at a temperature of 30° C. and a relative humidity of 80° C. The toner scattering that occurs at this time was investigated and judged based on the following evaluation.

◎: No toner scattering O: Some toner scattering △: Toner scattering a lot The sample was left for 24 hours under the following conditions, and the weight increase rate after humidification with respect to the weight of humidification 611 is shown in graphs.

(c) Non-offset property: The fixing temperature of the copying machine was changed for each developer prepared, and the temperature at which offset occurred was investigated at each temperature.

(k) Resistance to PVC staining:
A PVC sheet was placed and a load of 100 g/cm was applied.

After being left at 50° C. for 24 hours, the PVC sheet with the image on the surface was peeled off and the remaining state of the image was observed.

02 The image has not been transferred to the PVC sheet ○: Part of both images has been transferred to the PVC sheet △: Most of the image has been transferred to the PVC sheet X: The entire image has been transferred to the PVC sheet The following margins (invention (Effects) According to the method for producing an electrophotographic toner according to the present invention, resolution 9 image density 9 gradation property, moisture resistance and non-offset property are excellent, and in particular, durability is excellent.

A toner with excellent charging stability, cleaning properties, and anti-blocking properties can be obtained. Furthermore, in addition to the above characteristics, a toner having excellent vinyl chloride stain resistance can be obtained in high yield.

Claims (1)

[Claims] 1. (A) General formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, R_1 represents hydrogen or a methyl group, and R_2 represents a carbon number of 1 to 6. 10 to 60% by weight of a phthalimide monomer represented by [representing an alkylene group] and 90 to 40% by weight of (B) other polymerizable monomers to a total of 100% by weight, and a coloring agent and/or the emulsion polymerization liquid obtained by emulsion polymerization in the presence of magnetic powder is salted out to a particle size suitable for toner, and then heat treated at a temperature higher than the glass transition point of the main resin component. Features: A method for producing toner for electrophotography.