JPS61167955A - Preparation of electrophotographic toner - Google Patents

Abstract

PURPOSE:To enhance cleanability, triboelectrification stability, resistances to blocking and offset by adding an aq. dispersion of an offset inhibitor during polymn., at the time of >=90wt% polymn., before or after solidification. CONSTITUTION:The aq. dispersion of the offset inhibitor is added during polymn., at the time of >=90wt% polymn., before and/or after solidification at the time of preparing an electrophotographic toner, and polymn. is conducted after emulsification dispersion or during it at a temp. of 20-120 deg.C, and a cross- linking agent is added in an amt. of 0-20wt% of the total polymerizable monomer, and a mixing ratio of monomer to aq. medium is, preferably, 40/60-90/10 by weight. An emulsifier is added to the monomer in an amt. of 0.01-10wt%, and a polymerization initiator is added in an amt. of 0.01-10wt%, thus permitting the obtained electrophotographic toner to be superior in cleanability, triboelectrification stability, and blocking resistance, suitable for dry development, and prevented from offset trouble, and the obtained image to be superior in resolution, image density, and gradation.

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 light compensation 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 toner image is visualized using a developer containing toner. This visualized toner image.

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 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, toners for such dry developers have been produced by melt-kneading a colorant such as carbon black and/or magnetic powder such as magnetite into a thermoplastic resin to form a dispersion, and then adding an appropriate amount of the mixture. Toners have been produced by mechanically applying impact force with a crushing device to crush the dispersion to a desired particle size, and if necessary, further classifying it to form a toner. law).

Such methods not only require a large amount of energy for melt mixing and crushing.

The produced toner necessarily has a number of drawbacks.

In particular, when using desirable resins in the melt mixing process and the crushing process, 1. For example, if a resin that is easily melted is used, toner aggregation (caking) during storage and fogging due to toner filming on the photoconductor may occur. In addition, if a resin that is easily crushed is used, it will be crushed in the current machine and become fine toner, resulting in burr and dirt inside the machine.

In addition, the colorant dispersed in the resin appears on the surface of the crushed 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 development such as contamination and contamination of the surface of the photoreceptor.

In order to solve these drawbacks of the pulverization method, the Special Publication No. 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 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 the nine toners obtained by the grinding method have been overcome, it has been found that it introduces new drawbacks. That is, since the obtained toner particles are perfectly spherical, the cleaning properties are poor, and the emulsifier or suspending agent remains in the toner particles.

Charging stability and blocking properties deteriorate.

In general, in electrophotography, the fixing methods for electrostatic images are heat roll method and pressure fixing method.

Various methods are known, such as the high frequency heating method and the flash method, but the heat roll method is currently the most common method.

In the hot roll method, there is an oil coating method in which a mold release agent such as silicone oil is applied to the roll surface, and a material with excellent mold release properties such as Teflon or silicone rubber is used instead of a mold release agent such as silicone oil. There is an oil-less method in which fixing is performed using a roll. In either case, there is a problem of offset development in which toner melted by heat transfers to a hot roll and stains a self-supporting member such as paper.

A number of methods have been proposed to prevent such an offset phenomenon, and one of them is a method of adding a resin mainly composed of polyolefin to the toner in order to increase the releasability of the toner.

When manufacturing toner using the suspension polymerization method, the
Publication No. 13731 states, ``The method is characterized by including a step of polymerizing monomers that are polymerized to form the constituent molecules of a dry toner for fixed electrostatic charging on a heating roller in the presence of an offset inhibitor. ”, and there is a method of adding an offset inhibitor at the time of one polymerization.

(Problems to be Solved by the Invention) However, in this method, the polyolefins serving as offset inhibitors disrupt the hydrophobic/R water balance of the polymerization system, resulting in a polymerization solution containing many aggregates.

In addition, since polyolefin is more hydrophobic than the styrene-acrylic resin, which is a constituent molecule of the toner, it is localized in the core of the toner particles and hardly exists on or near the surface of each particle, resulting in less offset resistance. Amashi does not appear.

The present invention solves these problems in the conventional toner manufacturing method, and has excellent two-tone image density and two-tone resolution, as well as particularly improved IJ, printing properties, charging stability, and blocking properties. An object of the present invention is to produce an electrophotographic toner having excellent offset resistance and suitable for dry development using an emulsion polymerization method, and to provide a method for producing the toner that does not require a pulverization step.

(Means and effects for solving the problems) The present invention emulsifies and disperses a dipolymerizable monomer in the presence of a colorant and/or magnetic powder and polymerizes it to produce a main resin component. In a method for producing an electrophotographic toner in which polymer particles in a polymerization solution are coagulated to a particle diameter of 9 suitable for the toner, the polymerization rate is 9 during polymerization of an offset inhibitor dispersion.
The present invention relates to a method for producing an electrophotographic toner, characterized in that it is added at a time of 0 weight tS or more, before coagulation, and/or after coagulation.

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

During this polymerization, a colorant and/or magnetic powder and a polymerization initiator are present. In addition, toner property improvers such as charge control agents, fluidity improvers, and cleaning performance improvers, stabilizers for assisting emulsification and dispersion, and chain transfer agents 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 at the same time, or the polymerizable monomer is added to the aqueous medium in which the emulsifier is dissolved. However, they may be mixed by stirring.

As the polymerization initiator, a water-soluble polymerization initiator or an oil-soluble polymerization initiator is used, and these may be used in combination. The polymerization initiator may be added after emulsification and dispersion, but it is preferable to dissolve the water-soluble polymerization initiator in an aqueous medium beforehand at the time of emulsification and dispersion, and the oil-soluble polymerization initiator should be added to the dipolymerizable monomer. It is preferable to dissolve the amount in advance.

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 toner property improvers used as necessary. Further, a stabilizer may be used as necessary, but it may be added after the above-mentioned emulsification and dispersion, and may be used by being dissolved in the 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 a monopolymerizable monomer.

Polymerization is carried out for 20 minutes after or while emulsifying and dispersing.
Preferably it is carried out at a temperature of -120°C.

In particular, it is preferable to carry out at a temperature of 50 to 80°C.

This polymerization is preferably carried out until the polymerization rate reaches 99% by weight or more, particularly preferably 99.9% 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 nine polymerization preferably has a weight average molecular weight of 50,000 or more.

If the molecular weight becomes too small, cleaning properties will be affected.

Blocking resistance tends to decrease.

Furthermore, the obtained polymer has a glass transition point of 30 to 90°C.
It is preferably 50-80''C, especially 50-80''C.

If the glass transition point is too low, the blocking resistance tends to decrease, and if the glass transition point 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 polymerization results in particles of about 3 μm or less.

Next, materials used for monopolymerization will be explained.

Examples of the polymerizable monomer 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-chlorostyrene, 3,4-dichlorostyrene Styrene and its derivatives such as ethylene, propylene, butylene, imbutylene, unsaturated monoolefins, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride and other vinyl halides, vinyl acetate, vinyl clopionate, Vinyl esters such as vinyl benzoate and vinyl butyrate.

Methyl acrylate, ethyl acrylate, globil acrylate, n-butyl acrylate, isobutyl acrylate,
Pentyl acrylate, n-octyl acrylate, dotesyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2='lolethyl acrylate, phenyl acrylate.

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

n-butyl methacrylate, inbutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate , α-methylene aliphatic monocarboxylic acid esters such as diethylamine ethyl methacrylate.

Acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyglobyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, optionally Acrylic acid, methacrylic acid, maleic acid, fumaric acid, etc. can also be used. Also, vinyl methyl ether,
Vinyl ethers such as vinyl carbazole and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropyl vinyl ketone, and N-vinylpyrrole.

N-vinylcarbasol, N-vinylindole.

N-vinyl compounds such as N-vinylpyrrolidone and hinylnaphthalene salts can be used alone or in combination of two or more. When styrene or a styrene derivative is used in an amount of 40 to 100% by weight among these polymerizable monomers, the toner has excellent fixing properties when copied onto paper using an electrophotographic copying device.

Moreover, 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, 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, jNIN-divinylaniline, Divinyl compounds such as divinyl ether and divinyl sulfite, compounds having three or more vinyl groups, etc. can be used alone or as a mixture. The amount of crosslinking agent used is θ~20 weight based on the total amount of polymerizable monomers.
%, particularly preferably 0 to 5% by weight.

Water is mainly used as the aqueous medium used for emulsification and dispersion. The ratio of the above polymerizable monomer and aqueous medium is the former/
The latter is preferably in a weight ratio of 40/60 to 90/10. If this ratio is too small, emulsification and dispersion will occur, and if this ratio is too large, productivity will decrease.

As the emulsifier, an anionic surfactant, a cationic surfactant, a zwitterionic surfactant, or a nonionic surfactant 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 the two-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, alkyl sulfate ester salts such as sodium lauryl sulfate and sodium lauryl sulfate, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalenesulfonic acids. salts, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonic acid formalin la compound * polyoxyethylene alkyl sulfate ester 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 cationic surfactants include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary anthonium 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 10 per polymerizable monomer.
It is preferably 0.65 to 5% by weight, particularly preferably 0.65 to 5% by weight. If the amount of emulsifier used is too small, stable emulsion polymerization will be difficult, and if the amount of emulsifier is too large, the moisture resistance of the resulting toner will be reduced.

Stabilizers include polyvinyl alcohol, starch,
There are water-soluble polymer substances such as methylcellulose, carboxymethylcellulose, and hydroxyethylcellulose.
These are preferably used in an amount of 0 to 1% by weight based on the 9-polymerizable monomer.

Examples of water-soluble polymerization initiators include potassium persulfate,
Persulfates such as ammonium persulfate, hydrogen peroxide, 4.4
'-azobiscyanovaleric acid, 42'-azobis(2-amidinopropane) dihydrochloride, 1-butyl hydroperoxide, cumene hydroperoxide, etc. can be used.

Particularly when persulfate is used, the sulfate anion radical (sO;), which serves as an initiating active site, exists on the surface of the monomer, and the hydrophilic group of the SO″4 group and the charged particles are stabilized. It is.

It is easy to obtain an emulsion with a relatively uniform particle size.

The water-soluble polymerization initiator described above may be used in combination with a reducing agent. As the reducing agent, commonly known reducing agents such as sodium metabisulfite and ferrous chloride can be used. The reducing agent does not necessarily need to be used, but when used, it is preferably used in an amount equal to or less than the amount of the water-soluble polymerization initiator.

Examples of oil-soluble polymerization initiators include peroxides such as benzoyl peroxide and t-butyl perbenzoate, and azo compounds such as azobisisobutyronitrile and azobisisobutylvaleronitrile. It is preferable to use it by dissolving it in the body.

The amount of polymerization initiator used is 0.01 per polymerizable monomer.
It is preferably from 10% to 10% by weight, preferably from 0.1 to 5% by weight. Too little polymerization initiator.

The polymerizable monomer is not completely polymerized and remains in the toner, which deteriorates the properties of the toner.

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

Colorants preferably used in the present invention include:

Pigments or dyes may be mentioned such as Shiishima carbon black, nigrosine dye (C,1, Koji 50415)
.

Aniline Blue (C, 1, Fish 50405), Calco Oil Blue (C, 1, & azoec Blue 3)
), Chrome Yellow (C, 1, Fish 14090), Ultramarine Blue (C, 1, N 177103), DuPont Oil Red (C, 1, N 26105), Orient Oil Reddna 330 (C, 1, Nu 60505)
, Quinoline Yellow (C, 1, N1147005
), methylene blue chloride (c, r, demon 52015
), 7 Talocyanine Plue (C, 1, Fish 74160)
, malachite green off-salate (C, 1, N[14
2000), Lamp Black (C, 1, Magnetic 7726)
6), Rose Bengal (C, I.

8145435), 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, about 1 to 30% by weight in the toner.

It is preferably used in a proportion of 5 to 15% by weight.

The pigment or dye may be subjected to various treatments for the purpose of increasing its dispersibility in the double polymerization reaction system or in the toner of the present invention. The treatment includes, for example, treatment of nigrosine dye (C, I, MI150415) with an organic acid such as stearic acid or maleic acid.

Among these colorants, two particularly preferred in the toner K of the present invention are 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 an oxidizing agent such as oxygen, ozone, and nitric acid, and surface adsorption treatment with an organic acid ester such as dibutyl phthalate and dioctyl phthalate.

When using carbon black as 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 shell polymerization, but if the monopolymer component is too large, the viscosity tends to become too high when dispersed in monopolymerizable monomers. 1. Workability decreases.

The amount of grafted carbon black used is preferably determined by the amount of carbon black component.

The magnetic powder is used when producing a magnetic toner and can also serve as a coloring agent. Preferred magnetic powders include iron such as magnetite or ferrite;
Alternatively, there are oxides or compounds of ferromagnetic elements such as nickel and cobalt. These magnetic powders have a particle size of 0.0
A powder of 1 to 3 μm is preferable, and the surface of the magnetic powder may be treated with a resin, a titanium coupling agent, a silane coupling agent, a higher fatty acid metal salt, or the like. These magnetic substances are used in an amount of 20 to 80% by weight based on the toner.
, preferably 35 to 70% by weight. Less than this amount may be used as a coloring agent.

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

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 afterwards. The content of each of these is preferably 0 to 3% by weight based on the toner of the present invention. Examples of fluidity improvers include silane, titanium, aminium, calcium, magnesium, and magnesium oxides, or those obtained by hydrophobizing the above 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, by selecting monopolymerizable monomers and colorants, the charge amount and charge polarity of the product toner can be freely adjusted, but the charge amount and charge polarity can be adjusted to desired values. For this purpose, a charge control agent may be used in combination with the colorant in the toner of the present invention.

Charge control agents preferably used in the present invention include azo dyes such as Spiron Black TRH and Spiron Black TPH (Hodogaya Chemical Co., Ltd.), p-fluorobenzoic acid, p-nitrobenzoic acid, and 2,4-di Aromatic acid derivatives such as butylsalicylic acid, dibutyl-tin oxide, dioctyl-
Examples include tin compounds such as tin oxide.

these are.

It is preferably used in an amount of 0 to 5% by weight based on the polymerizable monomer.

In the present invention, after the main resin component is produced by double polymerization, a coagulant is added to the resulting polymerization solution to coagulate particles containing the colorant and/or magnetic powder.

Therefore, by appropriately aggregating the polymer particles in the polymerization liquid, the polymer particles have a larger average particle size than the polymer particles in the two-polymerization liquid, and are suitable for toners that are imperfectly spherical and do not require pulverization. particles can be obtained.

Here, the particle size distribution of the aggregated particles should be 1 to 100 μm! It is preferable to adjust the illuminance, especially 3 to 70μ
It is preferable to adjust it so that it becomes mK.

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 coagulant in an amount of 0.1 to 5 times, preferably 0.3 to 3 times, the weight of the emulsifier in the physical polymerization solution. If too little coagulant is used.

If the coagulation 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 become too large.

Since incompletely spherical toner particles are obtained through this coagulation step, the toner particles have excellent cleaning properties. Moreover, since the emulsifier is also removed by this coagulation step, blocking resistance and charging stability are also improved.

In this coagulation process, mixing of the double polymerization solution and the coagulant can be carried out in various ways, such as by dropping the polymerization solution little by little into the aqueous coagulant solution while stirring, or by mixing the aqueous coagulant solution and the polymerization solution at a fixed ratio. can.

In this coagulation step, the temperature is not particularly limited, but is preferably from room temperature to 150°C.

It is preferable to carry out the coagulation at a temperature above the softening point of the main resin component (as well as the heat treatment operation), and if solidification is carried out at a temperature below the softening point, then the salting-out solution is heated above the softening point of the polymer. (heat treatment operation) is particularly preferred. Such a heat treatment operation increases the bulk density of the particles of the main resin component, improving moisture resistance, offset resistance, and durability.

It is also possible to add a large amount of coagulant to the polymerization liquid in the coagulation process to obtain a large coagulate, and then crush this to obtain a particle size of 9 particles suitable for toner. This has the effect that the additive can be uniformly dispersed in the resin, but due to the pulverization, the toner has a shape closer to that of the pulverized toner than the toner according to the present invention.
Therefore, cleaning properties and toner fluidity are poor.

On the other hand, in the present invention, the particles obtained by coagulation can be made into toner as is or by only being classified into two, and the shape of the toner particles is different from the asymmetric amorphous shape like pulverized toner. Different.

Also, it is not perfectly spherical, but rather imperfectly spherical.

Excellent cleaning properties.

Examples of the coagulant 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 coagulants can be used alone or in combination, but preferred coagulants are magnesium sulfate, aluminum sulfate, barium chloride, magnesium chloride, calcium chloride,
Sodium chloride and/or a mixture thereof with an inorganic acid. These coagulants are preferably used as a 0.1-1.0% by weight aqueous solution, particularly a 0.1-5% by weight aqueous solution.

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

Washing here is preferable in order to completely remove the emulsifier adhering to the 9 particles, thereby improving the charging stability and blocking property as well as the above-mentioned coagulation. Washing is preferably carried out with warm water of 40 to 60°C.

Note that the post-solidification heat treatment operation may be inserted during the washing step or between two or more washing steps.

In addition, in the present invention, the dispersion of the offset inhibitor is (a) added to the polymerization solution during polymerization when the polymerization rate reaches 90% by weight or more, and (b) after the completion of polymerization. It is essential to add it to the polymerization solution before coagulation and/or (C) add it after coagulating the polymerization solution after completion of polymerization. The above-mentioned dispersion of the anti-offset agent is the above-mentioned (a) and (b).
) and IC), and may be added multiple times.

If the dispersion of the offset inhibitor described above is added from the time when the polymerization rate in polymerization is 90% by weight to before solidification after the completion of one polymerization in a year, the offset inhibitor will be added to the core of the polymer particle at the end of one polymerization. Not present, but present between the polymer particles and on the surface of the particles obtained by agglomeration of polymer particles by coagulation, and when a dispersion of an offset inhibitor is added after completion of polymerization. , the anti-offset agent is attached to the surface of the particles obtained by coagulation.

On the other hand, if a dispersion of an offset inhibitor is added when the polymerization rate of 1 polymerization is earlier than 90% by weight, especially at the start of W polymerization, the offset inhibitor will be present in the core of the polymer particles at the end of polymerization. For.

Even if particles obtained by coagulating this are used as a toner, the effect of preventing offset is extremely small.

Furthermore, when the offset inhibitor is added after the completion of the double polymerization, it is preferably added before the heat treatment described above. This is because the anti-offset agent is more likely to adhere to the surfaces of the two particles if the heat treatment is performed before the heat treatment than if it is performed after the heat treatment.

In the present invention, the offset inhibitor dispersion is a liquid in which the offset inhibitor is dispersed in the form of fine particles in water as a continuous phase.

Here, the anti-offset agent used is one that has an anti-offset effect and is dispersible in water.2 For example, various natural waxes such as carnauba wax,
Hydrogenated castor oil, low molecular weight olefin polymers, etc. are 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, and has a low molecular weight.

Here, the olefins include ethylene propylene,
Examples of monomers other than olefins include butene-1 and the like, and examples of monomers other than olefins include acrylic esters and methacrylic esters. Examples of such low molecular weight olefin polymers include polyalkylenes described in JP-A-55-153944 and low-molecular-weight olefin copolymers described in JP-A-50-93647. can do. Furthermore, two or more of the above-mentioned offset inhibitors may be used in combination.

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 chemistry, but generally the weight average molecular weight (Mw) is 1.
000-45000. It is preferably 2,000 to 6,000°C, and preferably has a softening point of 100 to 180°C, particularly preferably 130 to 160°C.

It is preferable that the anti-offset agent in the dispersion has an average particle size of 5 μm or less and does not contain particles with a particle size exceeding 20 μm. If the particle size is too large, some of the toner particles obtained by the present invention do not contain an anti-offset agent.

Moreover, in the above-mentioned dispersion liquid, it is preferable that the ratio of anti-offset agent and water is 515 to 9/1 in weight ratio of the former/latter. If this ratio is too small, the stability of the dispersion liquid will be reduced, and if this ratio is too large, the processing efficiency will be reduced.

There are no particular limitations on the method for producing the above dispersion. For example, a solid or liquid anti-offset agent can be mixed with a homomixer,
Homogenizer, Disperser - 1 Method of dispersing in water using a machine such as an ultrasonic dispersion machine 2 Method of manufacturing by dispersing and polymerizing monomers capable of polymerization reaction in water. In the former dispersion method, 9 improvements in the stability of the dispersion and 1 miniaturization of particles are achieved.

Anionic or nonionic surfactants may also be used. The type and amount of surfactant vary depending on the offset inhibitor to be dispersed, but the amount is preferably 10% by weight or less based on the offset inhibitor. If there is too much surfactant, a large amount of surfactant will remain in the final product, the toner, and the toner will become hygroscopic, resulting in poor storage stability.

Charging characteristics will be adversely affected. 2.If the resin to be dispersed is solid at room temperature, heat it above the softening point of the resin, or
Alternatively, it is preferable to add a small amount of an organic solvent to plasticize it.

On the other hand, the latter polymerization method is divided into emulsion polymerization method and suspension polymerization method, but emulsion polymerization method is preferable because it produces fine particles. The emulsion polymerization method is carried out by emulsifying and dispersing a dipolymerizable monomer in an aqueous medium containing an emulsifier and polymerizing it.

It is preferable that the amount of the emulsifier to be removed is 100% or less by weight of the offset preventing agent, similar to the above-mentioned surfactant. The negative effects of too much emulsifier are similar to those for surfactants described above.

In the method of the present invention, there is no particular limit to the amount of the anti-offset agent dispersion added, but the anti-offset agent is contained in the toner in an amount of 0.1 to 30% by weight. If the amount is less than 0.1% by weight, the offset prevention effect will not be exhibited, and if it exceeds 30% by weight, the image quality, including the single image intensity, tends to deteriorate significantly.

The amount of the above dispersion liquid is determined based on the weight of the polymer particles obtained by bipolymerization or the particles obtained by coagulation and the amount of offset inhibitor to be contained so that the offset inhibitor falls within the above range. Added as a guide.

The toner obtained according to the present invention can be obtained through the development process of
For example, the cascade development method described in U.S. Pat. No. 2,618,552, U.S. Pat.
The magnetic brush method described in US Pat. No. 65, the powder cloud method described in US Pat. No. 4,221.776, and the touchdown method described in US Pat. Development method, JP-A-55-1
The so-called jumping method described in Publication No. 8656,
It can be used in the so-called bipolar magnetic toner method, in which the necessary toner charge is obtained by frictional charging of magnetic toner particles produced by a pulverization method as a carrier.

Furthermore, the toner obtained according to the present invention can be used not only by a hot roll fixing method but also by a flash fixing method.

Other fixing methods such as oven methods can also be used. 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.

(Example) Next, the present invention will be explained in detail based on examples.

The present invention is not limited to this. In addition.

In the examples, "chi" means "% by weight" unless otherwise specified.

Example 1 (1) Production of emulsion polymerization solution 31! Grafted carbon (
Craft Carbon GP-E-2. Manufactured by Ryoyu Kogyo ■) 100
9, 400 g of styrene as polymerizable monomers, 120 g of butyl acrylate, and 0.6 g of t-dodecylmercaptan as a chain transfer agent.

Mixing and dispersion was performed using a homomixer at 300 Or, p, m for 30 minutes.

Next, 1420 g of ion-exchanged water was added to this carbon dispersion.
As emulsifiers, sodium dodecylbenzenesulfonate 129, an anionic surfactant, and Noniball PE-68, a nonionic surfactant (oxypropylene-oxyethylene block polymer manufactured by Sanyo Chemical Co., Ltd.) 3
G, Neugen EA170 (polyoxyethylene glycol nonylphenyl ether manufactured by Daiichi Kogyo Seiyaku ■) 3 g
and an aqueous solution in which ammonium persulfate 129 was dissolved as a polymerization initiator, and the mixture was further heated at 3000 r, p with a homomixer.
, m for 30 minutes to obtain a black pre-emulsion.

Next, a 3t! was equipped with a stirring device, nitrogen inlet, thermometer and condenser. The black pre-emulsion was transferred into a four-piece separable flask, and the flask was polymerized at a temperature of 70° C. for 5 hours under a nitrogen stream, and then cooled to obtain an emulsion polymerization liquid. The polymerization rate at this time was 99.5. Also 9
The molecular weight of the polymer was measured by gel chromatography using a standard polystyrene calibration curve, and the weight average molecular weight (Mw) was 86,000. Number average molecular weight (Mn
) 30,000.

(2) Production of anti-offset agent dispersion 750 g of low molecular weight polypropylene (Viscol 660P, manufactured by Sanyo Chemical Industries, Ltd.) was placed in the autoclave No. 31.
15g of sodium dodecylbenzenesulfonate (anionic surfactant) and 223g of ion-exchanged water! M is added, the container is sealed, and under pressure the melting point of Viscol 660P is about 2
The temperature was increased by 0°C to 154°C. Stirring speed: 100 O
r, I) 1 m, and kept warm for 30 minutes. The mixture was cooled while stirring, and one dispersion was taken out. When the particle size was measured using a Coulter counter, it was found to be a dispersion of particles with an average particle size of 1.2 μm and no particles larger than 5 μm.

(3) Coagulation step, emulsion II produced in final step (1)! and 24 mt of the dispersion prepared in (2)! were mixed. At this time, dust phenomena such as coagulation and sedimentation were not found. Furthermore, the above mixture was heated to 30°C.
196 aqueous solution of MgSO4 heated to 2I! While stirring thoroughly and maintaining the temperature of the aqueous solution at 30°C,
The mixture was added dropwise uniformly over a period of 1 minute to effect salting out. Furthermore.

The mixture was kept at this temperature for 30 minutes and then cooled to room temperature.

This slurry is then dehydrated using a centrifugal dehydrator.

The edges were turned over three times and washed with warm water at 50°C. Then,
It was dried in a dryer at 30 to 35°C to obtain a toner. When the particle size of the obtained toner was measured using a Coulter counter, the particle size was 1 to 50 μm, and the average particle size was 13 μm. Further, the glass transition point (Tg) was measured using a differential scanning calorimeter and found to be 73°C. This toner is further divided into 5-25J using a zigzag classifier (100MZR, manufactured by Alpin).
When the product was classified into Jm, the yield was 90% of that before classification.

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

Example 2 The same emulsion polymerization solution and anti-offset agent dispersion as used in Example 1 were used. Emulsion polymerization liquid 11 was heated to 30°C to form a 1% aqueous Mg5Oi solution 2I! While sufficiently stirring the aqueous solution and maintaining the temperature of the aqueous solution at 30° C., the solution was uniformly added dropwise over about 30 minutes to solidify. While stirring the coagulated emulsion polymerization liquid so that the offset inhibitor is uniformly salted out,
24 ml of anti-offset agent was added dropwise over 10 minutes. Sara K.

The mixture was kept at this temperature for 30 minutes and then cooled to room temperature.

Next, this slurry was subjected to centrifugal dehydration, washing and drying in the same manner as in Example 1 to obtain a toner. The resulting toner had a particle size Fi of 1 to 50 μm, an average particle size of 14 μm, and a glass transition point (Tg) of 73°C.

Example 3 A modified polyethylene wax (Suncoat manufactured by Sanyo Chemical Co., Ltd.) was dispersed and produced in the same manner as in Example 1 (2). Emulsion polymerization solution II of Example 1 (1)! Add the above dispersion 18 to
m1! was added, and the same coagulation and final steps as in Example 1 were performed, and the particle size was 2 to 100 μm, the average particle size was 15 μm, and the glass transition point (Tg) was 73°C.

A second classification was performed to obtain a toner having a size of 5 to 25 μm.

Example 4 (1) Emulsification and dispersion - Production of polymerization liquid 31! Grafted carbon (
Craft Carbon GP-E-2. Manufactured by Ryoyu Kogyo ■) 100
9, styrene 4009, butyl acrylate 1209.9 as polymerizable monomers. Ao o
Mixing and dispersion was carried out for 30 minutes at o r and p m -.

Next, this dispersion was mixed with 1420% ion-exchanged water and dodecylbenzenesulfonic acid, an anionic surfactant, as an emulsifier. / Nonionic surfactant Noniball PE-68 (oxypropylene-oxyethylene block polymer manufactured by Sanyo Chemical Industries, Ltd.) 39. An aqueous solution in which 3 g of Neugen EA170 (Daiichi Kogyo Seiyaku ■ polyoxyethylene glycol nonylphenyl ether) was dissolved was added and emulsified for 30 minutes using a homomixer at 3000 r, p, m to obtain a black pre-emulsion.

Next, 31! was equipped with a stirring device, nitrogen inlet, thermometer and condenser. The black pre-emulsion was transferred into a four-piece separable flask, and the flask was polymerized at a temperature of 70° C. under a nitrogen stream for 5 hours, and then cooled to obtain a polymerization solution. The polymerization rate at this time was 99.5. The molecular weight of the dipolymer was determined by gel chromatography using a standard polystyrene calibration curve, and the weight average molecular weight (Mw) was 65,000. Number average molecular weight (Mn)3
It was 0,000.

(2) Coagulation process, final process Emulsion II produced in this way! and (2) of Example 1
Add 24 mj' of a dispersion prepared in the same manner as above.

The same coagulation and final steps as in Example 1 were carried out to obtain 2 particles with a diameter of 3 to 1.
The average particle size was 20 μm, the average particle size was 17 μm, and the glass transition point (Tg) was 73°C. Further classification was performed to obtain toner having a size of 5 to 25 μm.

Comparative Example 1 (No offset inhibitor added) The emulsion polymerization solution produced in (1) of Example 1 was coagulated without adding an offset inhibitor, and the same final step 2 was carried out.
Classification was performed to obtain toner.

Comparative Example 2 (Polymerization in the presence of offset inhibitor) (1) Production of emulsion polymerization solution Grafted carbon toog, styrene 4009, butyl acrylate 1209. t-dotesyl mercaptan 0.
69 and low molecular weight polypropylene (Viscol 550
P, made by Sanyo Chemical) 144g in a homomixer at 300 O
The mixture was mixed and dispersed for 30 minutes at r, p, and m.

Next, to 1300 g of ion-exchanged water, 24 g of sodium dodecylbenzenesulfonate, 6 g of nonionic surfactant Noniball PE-68 (manufactured by Sanyo Kasei) + 6 g of the same nonionic surfactant Noigen EA-170 (manufactured by Dai-Kogyo Seiyaku)
9 and an aqueous solution containing ammonium persulfate 129 as a polymerization initiator, and mixed with a homomixer.
The mixture was emulsified by further stirring at r, p, m for 30 minutes to obtain a black blur emulsion.

This black pre-emulsion T-31! The mixture was transferred to a four-piece parallel flask, 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 or more, and the molecular weight of the polymer determined in the same manner as in Example 1 was a number average molecular weight of 21,000.
．． The weight average molecular weight was 68,000.

(2) Coagulation step, final step The same conditions as in Example 1 (I To
A coagulation step and a final step were performed using an aqueous MgSO4 solution (30° C.), and further classification was performed to obtain a toner.

Using the toners obtained in Examples 1 to 4 and Comparative Examples 1 and 2, a plain paper copying machine (manufactured by Konishiroku Photo Industry ■, U-B
ixl 600), electrophotographic toner Example 5 (1) Production of emulsion polymerization solution 31! Grafted carbon (
Craft Carbon GP-E-2. 'Made by 2 Yu Kogyo ■) 10
09, 360g of styrene and 1809g of butyl methacrylate as monomerizable monomers. 6 g of methacrylic acid and 0.6 g of t-dodecyl mercaptan were mixed in a homomixer at 300 g.
Mixing and dispersion was carried out for 30 minutes using Or, I) and m.

Next, an aqueous solution in which 18 g of sodium dodecylbenzenesulfonate, 4 g of nonionic surfactant Nonipol PE-68 (Sanyo Chemical Industries, Ltd. 11j), 9 g of ammonium persulfate, and hydrogen peroxide (30110G) were dissolved in ion-exchanged water 14709 was added to a homomixer. In addition, 300O at room temperature
A black pre-emulsion was obtained by emulsifying for 30 minutes with r.pom.

This black bleemulsion is 31! The mixture was transferred to a four-piece rosette flask, 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 determined in the same manner as in Example 1 was such that Mw was 9600.
0, Mn was 39,000.

(2) Coagulation step, final step Using the emulsion prepared in (1), the dispersion of low molecular weight polypropylene (Viscol 660P) used in Examples 1 and 2 and the modified polyethylene wax (
A toner was obtained by performing the same coagulation and final steps using an emulsion (Suncoat).

Further, two classifications were performed, and the same tests as in Examples 1 to 3 were conducted. Test conditions and test results are shown in Table 2.

Table 2 Note that the evaluation of the electrophotographic properties in the above Examples and Comparative Examples was performed in the following manner.

(a) Resolution: Copying was carried out on plain paper using the electrophotographic society Test Chart Magic 1 using the respective developers. A comparative evaluation was made to see if the copied images could be read in detail.

(b) Image density: The density of the black part of the copied paper was measured with a densitometer in the same manner as the resolution, and rated as 2.

Gradation: Same as resolution, 1 in the center of the test chart
Evaluation was made using a gray area divided into one level.

(C) IJ-Ning property: Using a copying machine, each of the prepared developers was used to make continuous copies at a temperature of 30°C and a humidity of 80°B and H, and evaluated by the number of copies made until a cleaning failure occurred. did.

(d) Blocking property: Each of the prepared toners was left for 72 hours at 50° C. and humidity of 95° C., and it was determined whether the toner blocked or towed.

Q: Excellent ×: Inferior It was evaluated as

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

O: Excellent X: Inferior It was evaluated as

(f) Durability: Using a copying machine, each prepared developer was tested at a temperature of 30℃ and a humidity of 80SRH for 10,000 hours.
Continuous copying was performed. The toner scattering that occurs at this time was investigated and judged based on the following evaluation.

◎: No toner scattering ○: Slight toner scattering is observed. Δ: Too much toner scattering ×: A large amount of toner scatters. (g) Hygroscopicity: Each prepared toner was heated at 25°C.

The room was left open at 24 hours at a humidity of 98°C, and the weight increase after humidification relative to the weight before humidification is shown by "C".

(hl Offset resistance: Remove the fixing section of a plain paper copying machine (U-Bix 1600 manufactured by Konishi Roku Photo Industry) to obtain an unfixed toner image, the upper side is composed of a Teflon coated roll and the lower side is a silicone rubber coated roll, +1 by using a fusing test device that can change the temperature of the upper roll!
Speed 70tmn/sec, pressure between rolls 0.5 kgf
/cm, and those with no offset were evaluated as ◯, and those with offset were evaluated as ×.

(Effect of the invention)

Claims (1)

[Claims] 1. A polymerizable monomer is emulsified and dispersed in the presence of a colorant and/or magnetic powder and polymerized to produce the main resin component, and the polymer particles in the resulting polymer solution have a particle size suitable for toner. In the method for manufacturing an electrophotographic toner, which involves coagulating so that Characteristic manufacturing method of electrophotographic toner.