JP2002091073A - Method for producing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing polymerized toner used as a toner which accompanies with no remarkable degradation of electrification even when left standing under high temperature and high humidity conditions and enables obtaining a more stable picture even at the time of durability. SOLUTION: In this method for producing polymerized toner, a polymerizable monomer composition containing at least polymerizable monomer and colorant is suspended in an aqueous medium containing a hardly water-soluble dispersion stabilizer and is polymerized, colored resin particles are formed, thereafter, acid is added into the suspension containing the colored resin particles, the hardly water-soluble dispersion stabilizer is solubilized into the aqueous medium, and the colored resin particles are filtered from the aqueous medium by a filter press method, subsequently are washed by water, are dehydrated and dried. Therein, it is a feature of this method for producing polymerizable toner that, after the colored resin particles are filtered from the aqueous medium by means of the filter press, water is supplied from the suspension supplying side of the finer press, the washing is performed and, thereafter, water is supplied from the filter side and, thus, the washing is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a toner for developing an electrostatic image or a toner for forming a toner-fixed image in a toner jet image forming method in an image forming method such as electronic printing. More particularly, the present invention relates to a method for producing a toner used in a fixing method in which a toner image is heated and fixed on a print sheet such as a transfer material.

[0002]

2. Description of the Related Art Conventionally, many methods have been known as electrophotography. In general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means. The latent image is developed with toner to form a visible image, the toner image is transferred to a transfer material such as paper if necessary, and then the toner image is fixed on the transfer material by heat, pressure, etc. Is what you get.

Various methods have been conventionally proposed as a method of developing with toner or a method of fixing a toner image.

Conventionally, toners used for these purposes are:
Generally, a colorant comprising a dye or a pigment is melt-kneaded in a thermoplastic resin, uniformly dispersed, then finely pulverized by a fine pulverizer, and the finely pulverized material is classified by a classifier to obtain a desired particle size. Has been manufactured.

[0005] Although this method can produce fairly good toners, it does have certain limitations, namely the choice of toner materials. For example, the resin colorant dispersion must be sufficiently brittle and capable of being pulverized in an economically feasible manufacturing apparatus. However, when the resin colorant dispersion is fragile to satisfy these requirements, when the dispersion is actually pulverized at a high speed, the particle size range of the formed particles tends to be widened, particularly at a relatively large ratio. There is a problem that fine particles are contained therein. Further, the toner obtained from such a highly brittle material is liable to be further powdered in a developing device such as a copying machine. Further, in this production method, it is difficult to completely and uniformly disperse solid fine particles such as a colorant in a resin, and depending on the degree of the dispersion,
Careful attention must be paid to the dispersing of the colorant because it causes fog increase during image formation, lower image density, and poor color mixing or transparency. Further, exposure of the coloring agent to the fracture surface of the pulverized particles may cause a change in development characteristics.

On the other hand, in order to overcome the problems of the toner caused by these pulverization methods, Japanese Patent Publication Nos.
Various polymerization toners and production methods thereof have been proposed, including the suspension polymerization toners disclosed in Japanese Patent Nos. 10799 and 51-14895 and the like. For example, in a suspension polymerization toner, a polymerizable monomer, a colorant and a polymerization initiator, and further, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to prepare a monomer composition. After that, the monomer composition is dispersed in a medium containing a dispersion stabilizer, for example, an aqueous phase using a suitable stirrer, and simultaneously subjected to a polymerization reaction to form toner particles having a desired particle size. obtain. In this method, since the pulverizing step is not included at all, the toner does not need to be brittle, a soft material can be used as the resin, and the colorant is not exposed on the particle surface, and the uniformity can be obtained. There is an advantage that a toner having triboelectricity can be obtained. Also, even if the classification step is omitted or classified because the particle size distribution of the obtained toner is relatively sharp,
A toner can be obtained with a high yield.

However, since the polymerized toner directly generates toner particles in the medium, the toner surface is easily affected by the medium.

For example, when the medium is an aqueous medium, generally a polar resin having a high polarity or a charge control agent tends to be localized near the toner surface. As a result, compared with the pulverized toner, a very small amount of the charge control agent can uniformly impart high chargeability to the toner, but a highly polar material such as the charge control agent is a very small part, Some are dissolved in an aqueous medium. Therefore, great care must be taken in the step of filtering the toner particles from the medium after the completion of the polymerization reaction.

That is, it is important how to efficiently and uniformly clean the surface of each toner particle. If the surface of each toner particle is not washed uniformly, the charge amount distribution of the toner becomes broad, and fog, toner scattering,
Image density reduction and the like are likely to occur.

[0010] In the polymerization toner disclosed in JP-A-8-160661 and its production method, the dispersion stabilizer is efficiently removed by performing dehydration and washing with a continuous belt filter and a siphon pillar type centrifuge, It is proposed that the above problems can be solved. If polymerized toner is manufactured using these proposed devices, a toner having excellent chargeability can be obtained as compared with the conventional one, but in terms of filtration efficiency and more uniform cleaning of the toner surface. Not satisfactory.

In the method for producing polymerized toner particles disclosed in Japanese Patent Application Laid-Open No. 2000-10341, among the methods for separating solid particles from a slurry, a filter press method, which is pressure filtration, is suitable for producing polymerized toner particles. Propose that. In vacuum filtration or centrifugal filtration, a part of the cake is cracked or the filter is easily clogged during the filtration. Therefore, it is difficult for the washing water to uniformly wash the cake. On the other hand, in the filter press method, filtration under reduced pressure and further dehydration by squeezing can be continuously performed, and cracking of the cake is unlikely to occur, and the filtration and washing steps can be continuously performed by flowing washing water to the cake. From
Very efficient. Furthermore, it proposes that it is preferable to supply water from at least the filter side in the above-mentioned point of washing with water by a filter press method after filtering by a filter press method.

However, particularly when the toner is left in an environment where the toner is hardly charged, such as under a high humidity, the charging property is not yet satisfactory.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device which is not exposed to high temperature / high humidity without a significant reduction in chargeability.
It is an object of the present invention to provide a method for producing a polymerized toner used for a toner capable of obtaining a more stable image even during durability.

Another object of the present invention is to provide a method for producing a polymerized toner having excellent productivity.

[0015]

The present invention provides a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous medium containing a poorly water-soluble dispersion stabilizer. After suspension and polymerization, to produce colored resin particles,
An acid is added to the suspension containing the colored resin particles to solubilize the poorly water-soluble dispersion stabilizer in an aqueous medium, and the colored resin particles are separated from the aqueous medium by a filter press method,
Next, in a method of producing polymerized toner particles by washing with water, dehydrating and drying, the colored resin particles are separated from the aqueous medium by a filter press, and then water is supplied from the supply side of the suspension of the filter press. The present invention relates to a method for producing a toner, comprising supplying and washing, and then supplying water from the filter side for washing.

As a result of intensive studies, the present inventors have found that, in order to further improve the chargeability of the polymerized toner particles under high temperature / high humidity, an acid is added to the suspension containing the colored resin particles, and It has been found that the method of solubilizing an aqueous dispersion stabilizer in an aqueous medium, filtering the aqueous dispersion medium from the aqueous medium by a filter press method, and washing with water has a great effect.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an acid is added to a cooled suspension containing colored resin particles after the polymerization is completed, and the suspension is stirred.
After dispersing the dispersion stabilizer of the poorly water-soluble inorganic compound, the dispersion stabilizer of the poorly water-soluble inorganic compound is removed by solid-liquid separation.

Examples of the acid used include hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, chromic acid, hydroiodic acid, sulfurous acid, citric acid, acetic acid, boric acid, carbonic acid, hydrofluoric acid, phosphoric acid, and nitrous acid. However, hydrochloric acid, sulfuric acid, nitric acid and the like are preferred in terms of cost and handling.

The pH after addition of the acid is preferably 3 or less, more preferably 2 or less, since the effect of removing the poorly water-soluble dispersion stabilizer is high.

The acid washing time is preferably several tens of minutes to 3 hours, and if it is 10 minutes or less, the effect of removing the poorly water-soluble dispersion stabilizer is low, and even if the washing is performed for 3 hours or more, a longer effect is obtained. I can't.

According to the production method of the present invention, an acid is added to the suspension containing the colored resin particles to solubilize the poorly water-soluble dispersion stabilizer in an aqueous medium, and then filtered from the aqueous medium by a filter press method. Separately, then washed with water, dehydrated, and dried to produce polymerized toner particles, in which a poorly water-soluble dispersion stabilizer is solubilized in an aqueous medium, and the aqueous medium is removed from the aqueous medium by a filter press method. After filtration, water is preferably supplied from the supply side of the suspension containing the colored resin particles to perform washing, and then water is preferably supplied from the filter side to perform washing.

In the present invention, after the colored resin particles are separated by filtration, the total washing water amount per 100 parts by mass of the colored resin particles is
It is preferred to wash using 200 to 1200 parts by weight. If the total amount of washing water is less than 200 parts by mass, removal of the dispersant becomes insufficient, and the obtained toner has high hygroscopicity and deteriorates chargeability. Conversely, if it exceeds 1200 parts by mass, a part of the polar components on the toner surface is eluted, and the chargeability is reduced.

Washing in which water is supplied only from the supply side of the suspension tends to cause overall uneven cleaning because the water supply source is small and uneven.

On the other hand, the method of washing by supplying water from the filter side not only can reduce the clogging of the filter, but also allows the washing water to be uniformly distributed in the cake, and the unevenness of washing hardly occurs. However, with only the method of cleaning by supplying water from the filter side, a portion where the waste liquid of the cleaning liquid passes is missing near the supply side of the suspension, so that the cleaning is partially insufficient.

Further, the present inventors supply 30 to 150 parts by mass of water per 100 parts by mass of colored resin particles from the supply side of the suspension to perform washing, and then supply water from the filter side to perform washing. In the case of performing, in the early stage of washing, since the strongly acidic suspension and cake gradually become neutral, a metal complex of alkylsalicylic acid as a charge control agent or
It has been found that a decomposition product of a complex salt or a mixture of a complex and a complex salt and a dissolved product of other additives in water are appropriately eluted to the toner surface, so that the chargeability of the dried toner particles is improved.

The preferable condition is that the ratio of the amount of washing water for supplying and washing water from the supply side of the suspension to the amount of washing water for supplying and washing water from the filter side is 1: 5 to 1:20. It is.

The washing water used in the present invention is washed with water having a total content of metal cations of less than 5 mg / l, and the total content of metal cations derived from the dispersion stabilizer in the washing wastewater is 5 mg / l. And then Na ⁺ , K ⁺ , Mg
Total content of ²⁺ and Ca ²⁺ is 20 mg / L or more and 15
By supplying and washing water of 0 mg / liter or less, a metal complex of alkylsalicylic acid as a charge control agent or
It is preferable because it is possible to control the state of the decomposition product of the complex salt or the mixture of the complex and the complex salt and the dissolved product of the other additives in water on the toner surface after drying. Further, Na ⁺ , K ⁺ , M
The total content of g ²⁺ and Ca ²⁺ is 20 mg / liter or more 1
Washing with 50 mg / liter or less of water is more preferably 50 to 500 parts by mass of water per 100 parts by mass of the colored resin particles. When the amount is less than 50 parts by mass, the effect of washing with water is hardly exhibited, and when the amount is more than 500 parts by mass, a metal complex or a complex salt or a complex of alkylsalicylic acid as a charge control agent is again used. Since the decomposition products of the complex salt mixture and the dissolved substances of other additives in water are removed, the amount is excessively reduced, and the chargeability of the toner deteriorates.

The pressing pressure of the filter press method is as follows:
It is preferably 98 to 980 kPa (1 to 10 kg / cm ² ), and at the time of washing with water from the filter side,
Washing while pressing is preferred. Pressing pressure is 98kP
If less than a, not only does the efficiency of filtration drop,
Uniform pressure is not applied to the cake in the filtration chamber, and uniform washing becomes difficult. On the other hand, when the pressure exceeds 980 kPa, the toner particles are deformed, and the high transferability resulting from the spherical shape of the polymerization toner is impaired, which is not preferable.

After the toner particles are washed with water, it is preferable to ventilate the toner particles so that the water content is 40% or less. Water content is 40
%, If the drying is performed in the next step, the drying efficiency will be poor, and the obtained toner will often be in an aggregated state, which is not preferable.

As the charge control agent used in the toner of the present invention, a known charge control agent can be used. As the charge control agent used in the toner for full-color images, a compound containing a carboxyl group is preferable. Used in a polymerizable monomer. In consideration of the effect of color, a colorless or white or light-colored crystalline state is preferable, and a metal compound of alkyl salicylic acid is particularly preferable for a color toner. As the metal compound, a metal complex or a metal complex salt or a metal complex And a mixture of metal complex salts, low-crystalline or non-crystalline ones,
It is preferably used.

The charge control agent is added in an amount of the polymerizable monomer 1
0.5 to 10 parts by mass per 100 parts by mass is preferred.

The toner of the present invention preferably contains a low softening point substance in order to improve fixability.
Compounds having a main maximum peak value measured according to ASTM D3418-8 of from 40 to 90 ° C are preferred. If the maximum peak is less than 40 ° C., the self-cohesive force of the low softening point substance becomes weak, and as a result, the hot offset resistance becomes weak, which is not preferable. On the other hand, if the maximum peak exceeds 90 ° C., the fixing temperature becomes high, which is not preferable. Further, in the case of obtaining a toner by a direct polymerization method, since the temperature of the maximum peak value is high because the granulation and polymerization are performed in an aqueous system, a substance having a low softening point mainly precipitates during the granulation and hinders the suspension system. Not preferred.

For the measurement of the temperature of the maximum peak value, for example, DSC-7 manufactured by Perkin Elemer Co., Ltd. is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

Specifically, paraffin wax, polyolefin wax, Fischer-Tropsch wax, amide wax, higher fatty acid, ester wax and derivatives or graft / block compounds thereof can be used.

The low softening point substance is preferably added to the toner in an amount of 5 to 40% by mass. If the addition is less than 5% by mass, the fixing property is lowered, and if it exceeds 40% by mass,
Also in the production by the polymerization method, coalescence of toner particles tends to occur at the time of granulation, and a toner having a wide particle size distribution is easily generated, which is not suitable for the present invention. As a specific method for encapsulating the low softening point substance, the polarity of the material in the aqueous medium is set smaller for the low softening point substance than for the main monomer,
Further, by adding a small amount of a resin or monomer having a large polarity, a toner having a so-called core / shell structure in which a low softening point substance is coated with an externally added resin can be obtained.

The polymerizable monomer used in the present invention includes styrene, o (m-, p-)-methylstyrene, m
Styrene monomers such as (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (Meth) acrylate monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylamide The body is preferably used. These can be used alone or in general in the published Polymer Handbook, 2nd edition III-pl39-192 (John Wire
y & Sons), the theoretical glass transition temperature (T
The monomer is appropriately mixed and used so that g) indicates 40 to 75 ° C. If the theoretical glass transition temperature is lower than 40 ° C., problems arise in terms of the storage stability of the toner and the durability stability of the developer. In some cases, the color mixture of each color toner is insufficient, resulting in poor color reproducibility.
The transparency of the HP image is significantly reduced, which is not preferable from the viewpoint of high image quality.

In the present invention, when a toner having a core / shell structure is produced, it is particularly preferable to add a polar resin. The polar resin used in the present invention includes a copolymer of styrene and (meth) acrylic acid,
Maleic acid copolymers, polyester resins and epoxy resins are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with a monomer in the molecule.
If a polar resin having many unsaturated groups is included, a cross-linking reaction occurs with the monomer forming the outer shell resin layer,
In particular, a full-color toner has an extremely high molecular weight and is disadvantageous for color mixing of four-color toner, which is not preferable.

In the present invention, an outermost resin layer may be further provided on the surface of the toner. The glass transition temperature of the outermost shell resin layer is preferably designed to be equal to or higher than the glass transition temperature of the outer shell resin layer in order to further improve blocking resistance, and it is preferable that the outermost shell resin layer is crosslinked so as not to impair fixability. . The outermost resin layer preferably contains a polar resin and a charge control agent for improving the chargeability.

The method for providing the outermost shell layer is not particularly limited, but examples thereof include the following method. 1. In the second half or after the end of the polymerization reaction, if necessary, a monomer in which a polar resin, a charge control agent, a cross-linking agent, etc. are dissolved and dispersed is added to the reaction system, the monomer is adsorbed, polymerized particles are added, and a polymerization initiator is added to carry out polymerization. Method. 2. If necessary, an emulsion polymerization particle or a soap-free polymerization particle composed of a monomer containing a polar resin, a charge control agent, a cross-linking agent, etc. is added to the reaction system, and aggregated on the surface of the polymerization particle.If necessary, heat or the like is used. How to stick. 3. A method in which emulsion polymerized particles or soap-free polymerized particles comprising a monomer containing a polar resin, a charge control agent, a cross-linking agent, and the like, if necessary, are dry-mechanically fixed to the toner particle surfaces.

As the colorant used in the present invention, a black colorant prepared by using carbon black as a black colorant, a magnetic substance, and a yellow / magenta / cyan colorant described below is used.

Examples of the yellow colorant include condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168, 180 and the like are preferably used. Further, C.I. I. Dyes such as Solvent Yellow 93 and 162 may be used in combination.

Examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8: 2, 48: 3, 48: 4, 57: 1, 81: 1, 1
22, 144, 146, 150, 166, 169, 17
6, 177, 184, 185, 202, 206, 22
0, 221, 238, 254 are particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66, etc. can be particularly preferably used.

These colorants can be used alone or as a mixture or in the form of a solid solution. In the case of a color toner, the colorant of the present invention is selected from the viewpoints of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in the toner. The colorant is used in an amount of 1 to 20 parts by mass per 100 parts by mass of the polymerizable monomer.

When a magnetic material is used as a black colorant, it is used in an amount of 40 to 150 parts by mass per 100 parts by mass of the polymerizable monomer, unlike other colorants.

Examples of the polymerization initiator used in the present invention include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile,
1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-
Azo-based polymerization initiators such as dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-
A peroxide-based polymerization initiator such as dichlorobenzoyl peroxide and lauroyl peroxide is used.

The amount of the polymerization initiator to be added varies depending on the target component ratio of the present invention, but is generally from 0.5 to 20% by mass, more preferably from 0.5 to 20% by mass, based on the polymerizable monomer. 10% by mass is used. The type of the initiator slightly varies depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.

In order to control the molecular weight distribution of the binder resin for toner of the present invention, it is preferable to further use a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like.

When suspension polymerization is used as the toner production method of the present invention, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate may be used as a dispersant, for example, as an inorganic oxide. , Magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, ferrite and the like.

These dispersants are used in the polymerizable monomer composition 10
It is preferable to use 0.2 to 10.0 parts by mass with respect to 0 parts by mass.

As these dispersants, commercially available ones may be used as they are, but in order to obtain finely dispersed particles having a uniform particle size, the inorganic compound is formed under high-speed stirring in a dispersion medium. You can also get.

For example, in the case of tricalcium phosphate, a dispersant suitable for a suspension polymerization method can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring.

[0053] These dispersants may be used in combination with 0.001 to 0.1 parts by mass of a surfactant. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used, and examples thereof include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and olein. Calcium acid and the like are preferably used.

The method for producing a toner of the present invention is specifically performed as follows.

A releasing agent comprising a low softening point substance, a colorant, a charge control agent, a polymerization initiator and other additives are added to the polymerizable monomer, and the mixture is uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser or the like. The allowed monomer composition is mixed with an ordinary stirrer or homomixer in an aqueous phase containing a dispersion stabilizer,
Disperse with a homogenizer, clear mixer, etc. In the suspension polymerization method, the polymerizable monomer system 100
It is preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to parts by mass.

Preferably, the agitation speed and time are adjusted so that the droplets of the monomer composition have the desired size of the toner particles, and granulation is performed. Thereafter, by the action of the dispersion stabilizer, stirring may be performed to such an extent that the particle state is maintained and the particles are prevented from settling. The polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and furthermore, in the latter half of the reaction to remove unreacted polymerizable monomers, by-products, and the like, or by partially distilling the aqueous medium after completion of the reaction. Is also good.

After the completion of the reaction, the pH is adjusted, the dispersion stabilizer is dissolved, and the resulting toner particles are washed, filtered, collected and dried by the washing method of the present invention.

The filtering and washing of the toner particles, which is a feature of the present invention, will be described with reference to FIG.

The suspension in which the dispersion stabilizer is dissolved is supplied to the filtration chamber from the liquid sending port 3. The filtrate that has passed through the filter cloth 2 is discharged from a filtrate port / wash water port 4. Next, washing water is supplied into the filtration chamber from the liquid sending port 3 to wash the cake, and the filtrate that has passed through the filter cloth 2 is discharged from the filtrate port / wash water port 4. After the pressing, the washing water is further supplied from the filtrate port / washing water port 4 through the filter cloth 2, the cake is washed, and the cake is discharged from the washing water port 5. After the washing is completed, aeration is performed using 4 or 5 to reduce the water content of the cake to 40% or less. Thereafter, the filter plates 1 are separated from each other, and the cake is discharged.

The discharged cake is dried by a dryer such as a fluidized bed dryer, a flash dryer, and a vacuum dryer to obtain toner particles.

An external additive may be added to the toner of the present invention for imparting various toner properties. As the external additive used, for example, the following are used.

Metal oxides (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metals Salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica, etc.

These external additives are used in an amount of 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the toner particles. These external additives may be used alone or in combination. Those subjected to a hydrophobic treatment are more preferable.

As a device for measuring the average particle size and the particle size distribution of the toner, Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.) is used. The electrolyte is about 1% Na using primary sodium chloride.
Prepare a Cl aqueous solution. As a measurement method, a surfactant as a dispersant in 100 to 150 ml of the electrolytic aqueous solution,
Preferably, the alkyl benzene sulfonate is 0.1 to 5
ml, and 2 to 20 mg of the measurement sample. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the measurement apparatus described above was used as an aperture.
The volume distribution and the number distribution were calculated by measuring the volume and number of the toner using a 00 μm aperture. then,
The volume-based weight average particle diameter (D4) (the representative value of each channel is defined as the representative value of each channel) determined from the volume distribution according to the present invention.

Details of the toner evaluation items in the examples described below are as follows.

Image evaluation was performed using a modified color copying machine CLC500 manufactured by Canon Inc. at a temperature of 23 ° C. and a humidity of 65%.
RH room temperature / humidity environment, temperature 30 ℃, humidity 80%
A durability test of 10,000 sheets was performed in a high-temperature / high-humidity environment of RH.

The image density is (5 mm square, 5 mm round, solid)
Is a numerical value measured by a Macbeth densitometer (manufactured by Macbeth).

The fog density was measured using a reflection densitometer (TOKYO).
DENSHOKU CO. LTD REFLECT
OMETER MODEL TC-6DS) (Ds is the worst value of the reflection density of the white background after printing is Ds, and Ds is the average reflection density of the paper before printing is Dr).
Dr was defined as the fog density. )did. When the fog density exceeds 2%, an image in which fog is conspicuous is obtained.

The transfer efficiency is as follows. A solid image of 10 cm ² is formed on the photoreceptor, and the amount of toner on the photoreceptor (W1) and the amount of toner on the paper after transfer (W2) are used. W2
/ W1 × 100 (%).

[0070]

Hereinafter, the present invention will be described in detail with reference to specific toner production methods, examples and comparative examples.

Table 1 shows the content of metal cations in each water used.
Shown in

[0072]

[Table 1]

<Example 1> First, ion-exchanged water (water A)
450 parts by mass of a 0.1 mol / l-Na ₃ PO ₄ aqueous solution was added to 710 parts by mass and heated to 60 ° C., and then, using a clear mixer (manufactured by M Technique Co., Ltd.) at 3,500 rpm. Stirred. 1.0 mol / liter-C
68 parts by mass of an aCl ₂ aqueous solution was added to obtain an aqueous medium of a compound of phosphoric acid and calcium having a pH of 5.6 and containing Ca ₃ (PO ₄ ) ₂ .

On the other hand, as the dispersoid, first, C.I. I. Pigment Yellow 93, an aluminum dialkylsalicylate compound and 100 parts by mass of a styrene monomer were dispersed for 3 hours using an attritor (manufactured by Mitsui Miike Koki Co., Ltd.) to obtain a colorant dispersion. Next, the rest of the above formulation was added to the colorant dispersion, heated to 60 ° C., and dissolved and mixed for 30 minutes. The polymerization initiator 2,2'-
8 parts by mass of azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition. (Monomer) Styrene 165 parts by mass n-butyl acrylate 35 parts by mass (colorant) I. Pigment Yellow 93 14 parts by mass (charge control agent) Aluminum di-t-butylsalicylate compound 2 parts by mass (polar resin) Saturated polyester 10 parts by mass (acid value 10 mg KOH / g, peak molecular weight 8500) (release agent) Ester wax (Peak temperature in DSC: 59.4 ° C) 25 parts by mass 0.2 parts by mass of divinylbenzene

The above polymerizable monomer composition was charged into the aqueous dispersion medium and granulated for 15 minutes while maintaining the rotation speed. Then, the stirrer was changed from a high-speed stirrer to a propeller stirring blade, the internal temperature was raised to 60 ° C, polymerization was continued at 50 rpm for 5 hours, and then the internal temperature was raised to 80 ° C for 8 hours. Was continued. After the completion of the polymerization reaction, the remaining monomer was distilled off at 80 ° C./reduced pressure, and the slurry was cooled to 30 ° C.

Next, the colored polymer particle suspension was transferred to a washing vessel, and dilute hydrochloric acid was added thereto with stirring, and the pH was adjusted to 1.5 at 2 hours.
After stirring for ₃ hours to dissolve the compound of phosphoric acid and calcium containing Ca ₃ (PO ₄ ) ₂ , filter press [NR-
PF-BL type: manufactured by Noritake Iron Works, compression pressure 490 kPa
(5 kg / cm ² )] from the liquid feed port 3 and filtered. Next, after supplying 50 parts by mass of ion-exchanged water from the liquid feed port 3 and washing, 800 parts by mass of ion-exchanged water was supplied from the washing water port 4 and washed while pressing. Further, 100 parts by mass of water B was supplied from the washing water port 4 for washing, ventilation was performed, and a colored resin particle cake having a water content of 25% was obtained.

Thereafter, the resultant was crushed and dried to obtain colored resin particles (toner particles). The weight average particle size of the obtained toner particles was 6.7 μm, and had a sharp particle size distribution.

To 100 parts by mass of the resulting toner particles, 0.7 parts of hydrophobic silica having an average particle size of 0.03 μm was added.
A part by mass and 0.7 part by mass of titanium oxide having an average particle size of 0.05 μm were added and mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) to obtain a toner. A developer was prepared by mixing 95 parts by mass of a magnetic material-dispersed resin carrier with 5 parts by mass of the toner.

In addition, the obtained toner particles were heated at 30 ° C.
/ 80% RH for 2 days, then add hydrophobic silica having an average particle size of 0.03 μm and titanium oxide having an average particle size of 0.05 μm and mix with a Henschel mixer to form a toner in the same manner as above. Further, 95 parts by mass of a magnetic material-dispersed resin carrier was mixed with 5 parts by mass of the toner to obtain a developer.

Table 2 shows the evaluation results. When an image output test was performed under normal temperature and normal humidity, in all cases, even at 10,000 sheets durability, there was no change in the image density at the initial stage and after the endurance, and a high-quality image without a hollow portion was obtained. In addition, problems such as toner fusion and memory ghost did not occur on the photoconductor made of an organic semiconductor. Further, a double-sided image was formed, but no offset was observed on both the front and back surfaces of the transfer material. When a similar image-drawing test was performed under high temperature and high humidity, similar results were obtained.

<Example 2> A toner was obtained in the same manner as in Example 1 except that the cleaning conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
It had a sharp particle size distribution of 8 μm. Table 2 shows the evaluation results.
It was shown to. Good results were obtained as in Example 1.

<Example 3> A toner was obtained in the same manner as in Example 1 except that the washing conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
The particle size distribution was sharp at 9 μm. Table 2 shows the evaluation results.
It was shown to. Almost good results were obtained in the same manner as in Example 1. However, when the developer was left at 30 ° C./80% RH for 2 days, the image density was slightly lower than the initial level, and the fog gradually increased. became. This is presumably because some of the polar components on the toner surface eluted because the amount of washing water was rather large.

<Example 4> A toner was obtained in the same manner as in Example 1 except that the cleaning conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
The particle size distribution was sharp at 7 μm. Table 2 shows the evaluation results.
It was shown to. Under normal temperature and normal humidity, almost good results were obtained as in Example 1. However, under high temperature and high humidity, the image density was slightly lower than the initial one, and fog gradually increased. 30
This tendency was particularly remarkable when the developer was allowed to stand at a temperature of 80 ° C./80% RH for 2 days. This is probably because the amount of washing water was rather small and the dispersant was not sufficiently removed.

Example 5 A toner was obtained in the same manner as in Example 1 except that the cleaning conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
It had a sharp particle size distribution of 8 μm. Table 2 shows the evaluation results.
It was shown to. Almost good results were obtained in the same manner as in Example 1. However, when the developer was left under high temperature and high humidity and left at 30 ° C./80% RH for 2 days, the fog was slightly increased from the beginning, and the developer was gradually increased. More. This is presumably because the amount of washing water from the suspension supply side was slightly small, and there was some unevenness in washing.

<Example 6> A toner was obtained in the same manner as in Example 1 except that the cleaning conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
It had a sharp particle size distribution of 8 μm. Table 2 shows the evaluation results.
It was shown to. Good results were obtained as in Example 1.

<Example 7> A toner was obtained in the same manner as in Example 1 except that the cleaning conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
The particle size distribution was sharp at 9 μm. Table 2 shows the evaluation results.
It was shown to. Good results were obtained as in Example 1. However, although the image density, fog, etc. were slightly inferior to those in Example 1, this was due to water having a total content of Na ⁺ , K ⁺ , Mg ²⁺ and Ca ²⁺ of 20 mg / L or more and 150 mg / L or less. It is considered that the control of the state of the charge control agent on the toner surface was insufficient because no cleaning was performed.

Example 8 A toner was obtained in the same manner as in Example 1 except that the cleaning conditions in Example 1 were changed as shown in Table 2. The weight average particle diameter of the obtained toner is 6.
The particle size distribution was sharp at 6 μm. Table 2 shows the evaluation results.
It was shown to. Although good results were obtained as in Example 1,
When the developer was left at high temperature and high humidity and left at 30 ° C./80% RH for 2 days, the image density, fog, etc. were slightly inferior. It seems that there are many.

Example 9 A toner was obtained in the same manner as in Example 1 except that the colorant of Example 1 was changed to Pigment Red 122 and 20 parts by mass. The obtained toner had a weight average particle size of 6.2 μm and a sharp particle size distribution. Table 2 shows the evaluation results. Good results were obtained as in Example 1.

Example 10 The colorant of Example 1 was replaced with C.I.
I. Pigment Blue 15: 3, 10 parts by mass, and the charge control agent was changed to a zinc di-t-butylsalicylate compound. The obtained toner had a weight average particle size of 6.6 μm and a sharp particle size distribution. Table 2 shows the evaluation results. Example 1
Similar good results were obtained.

<Comparative Example 1> A toner was obtained in the same manner as in Example 1 except that the washing conditions in Example 1 were changed as shown in Table 2 (only washing from the suspension supply side). The weight average particle size of the obtained toner was 6.8 μm and had a sharp particle size distribution. Table 2 shows the evaluation results. Due to unevenness in cleaning, the image density was low from the beginning and the fog was large under normal temperature and normal humidity, and the developer scattered from the developing device was conspicuous.

<Comparative Example 2> A toner was obtained in the same manner as in Example 1 except that the washing conditions in Example 1 were changed as shown in Table 2 (only washing from the suspension supply side). The weight average particle size of the obtained toner was 6.8 μm and had a sharp particle size distribution. Table 2 shows the evaluation results. Under normal temperature and normal humidity, the image density was low from the beginning, and under high temperature and high humidity, the image density gradually decreased and fog increased. further,
When left at 30 ° C./80% RH for 2 days and used as a developer, the image density is low from the beginning, the fog is high,
The scattering of the developer from the developing device was conspicuous. This is because even if the amount of washing water is increased, washing only from the suspension supply side causes uneven cleaning.

<Comparative Example 3> A toner was obtained in the same manner as in Example 1 except that the washing conditions in Example 1 were changed as shown in Table 2 (only washing from the filter side). The weight average particle size of the obtained toner was 6.8 μm and had a sharp particle size distribution. Table 2 shows the evaluation results. Under normal temperature and normal humidity, the image density was slightly low from the initial stage and fog was slightly increased, but an image almost similar to that in Example 1 was obtained. However, under high temperature and high humidity, the image density gradually decreased, and Increased. Further, when the developer was allowed to stand at 30 ° C./80% RH for 2 days, the image density was low from the beginning, the fog was large, and the developer was scattered from the developing device. This is because washing only from the filter side lacks a portion through which the waste liquid of the washing liquid passes near the supply side of the suspension, so that washing is partially insufficient.

Comparative Example 4 A toner was obtained by performing the same operation as in Example 1 except that the washing conditions in Example 1 were changed as shown in Table 2 (only washing from the filter side, water C). . The weight average particle size of the obtained toner was 6.7 μm and had a sharp particle size distribution. Table 2 shows the evaluation results. The image density was low from the beginning, fog was high from the beginning, and gradually increased. Further, scattering of the developer from the developing device was conspicuous. This is because the washing was only performed from the filter side, and the washing was partially inadequate.
^+, K ^+, because it is washed only with water containing Mg ²⁺ and Ca ^{2 +,} lysates in water degradation products and other additives of the charge control agent will be excessively removed, This is because the chargeability of the toner deteriorated.

[0094]

[Table 2]

[0095]

As described above, according to the production method of the present invention, it is possible to obtain a polymerized toner having good environmental stability of chargeability and capable of obtaining a stable image even during durability.

[Brief description of the drawings]

FIG. 1 schematically shows a filter press apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filter plate 2 Filter cloth 3 Liquid feed port 4 Filtrate port / wash water port 5 Wash water port

Claims (8)

[Claims] Claims: 1. A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is suspended in an aqueous medium containing a sparingly water-soluble dispersion stabilizer, and polymerized. After the particles are generated, an acid is added to the suspension containing the colored resin particles to solubilize the poorly water-soluble dispersion stabilizer in the aqueous medium, and the colored resin particles are removed from the aqueous medium by a filter press method. In a method of producing polymerized toner particles by filtering, then washing with water, dehydrating and drying, the colored resin particles are filtered from an aqueous medium by a filter press, and then a suspension of a filter press is supplied. A method for producing a toner, comprising: supplying water from the side to perform washing, and then supplying water from the filter side to perform washing. 2. The method for producing a toner according to claim 1, wherein the washing with water from the filter side is performed by injecting water while the filter press is in a compressed state. 3. The washing water supplied from the supply side of the suspension and washed is 30 to 150 parts by mass of water per 100 parts by mass of the colored resin particles.
3. The method for producing toner particles according to item 1. 4. The toner particles according to claim 1, wherein the amount of washing water supplied from the filter side and washed is 200 to 1200 parts by mass of water per 100 parts by mass of the colored resin particles. Production method. 5. The method according to claim 1, wherein said polymerizable monomer composition contains a metal compound of alkyl salicylic acid. 6. The toner according to claim 5, wherein the metal compound of alkyl salicylic acid is a low-crystalline or non-crystalline metal complex of alkyl salicylic acid, a metal complex, or a mixture of a metal complex and a metal complex. Manufacturing method. 7. The washing with water is carried out by washing with water having a total content of metal cations of less than 5 mg / l, and the total content of metal cations derived from the dispersion stabilizer in the washing wastewater is less than 5 mg / l. After that, Na ⁺ , K ⁺ , Mg ²⁺ and Ca ²⁺
7. The method for producing a toner according to claim 1, wherein water having a total content of 20 mg / liter to 150 mg / liter is supplied and washed. 8. Washing with water having a total content of Na.sup. ⁺ , K.sup. ⁺ , Mg.sup.2 ⁺ and Ca.sup.2 ⁺ of at least 20 mg / l and not more than 150 mg / l can be achieved by washing with 50 parts by weight of water per 100 parts by mass of the colored resin particles.
The method for producing a toner according to claim 7, wherein the amount is from 500 to 500 parts by mass.