JP2001235900A - Method for producing toner and system therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a toner by which an unreacted polymerizable monomer is uniformly and efficiently removed from toner particles obtained by polymerization and the control of the temperature of a dried product is facilitated. SOLUTION: A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to form colored polymer particles and these particles are washed and dehydrated. The resulting wet colored polymer particles are charged into an evacuative drying machine 1 and dried under reduced pressure while supplying a temperature controlled gas to substantially remove the dispersion medium and to reduce the amount of the polymerizable monomer remaining in the colored polymer particles to <=100 ppm. The objective toner particles are thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner and a system for producing a toner used in a recording method utilizing an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet method or the like.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat.
As described in, for example, US Pat. No. 691 and the like, a number of methods are known. Generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is formed. The image is developed using toner, and if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heating, pressure, or solvent vapor to obtain a copy. Further, as a method of developing using a toner or a method of fixing a toner image,
Conventionally, various methods have been proposed, and a method suitable for each image forming process has been adopted.

Conventionally, as a toner used for these purposes, generally, a coloring agent such as a dye or a pigment is melt-mixed in a thermoplastic resin and uniformly dispersed, and then has a desired particle size by a pulverizer or a classifier. Has been producing toner.

[0004] 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 is brittle enough,
It must be able to be comminuted in an economically feasible production equipment. However, if the resin colorant dispersion is made brittle to satisfy these requirements, the particle size range of the particles formed when actually pulverized at high speed tends to be widened, and in particular, a relatively large proportion of fine particles Problem arises. Further, such a highly brittle material is liable to be further pulverized or powdered when used for development in a copying machine or the like. Further, in this method, it is difficult to completely and uniformly disperse solid fine particles such as a colorant in a resin,
Depending on the degree of the dispersion, fog may increase, the image density may decrease, or the color mixing / transparency may be poor. Therefore, care must be taken in the dispersion. Further, exposure of the coloring agent to the fracture surface may cause fluctuations 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 toners by the suspension polymerization method disclosed in Japanese Patent Nos. 10799 and 51-14895 and the like. For example, in the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer composition. After that, the monomer composition is dispersed in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase using a suitable stirrer, and simultaneously subjected to a polymerization reaction to obtain toner particles having a desired particle size. obtain.

This method does not include a pulverizing step at all, so that the toner does not need to be brittle, a soft material can be used, and the classification step can be omitted, thereby saving energy. The cost reduction effect is large, such as shortening the time and improving the process yield.

Further, in recent years, the multifunction of the toner itself has been demanded, such as high image quality, full color, and energy saving of copying machines and printers. For example, to reduce toner particle size to support high resolution and digital system with higher image quality, to improve transparency of OHP image due to full colorization, and to reduce toner concentration to support low temperature fixing due to energy saving. It is required to contain a softening point substance and to shape toner particles which are effective for improving transfer efficiency to a transfer material. As a means for achieving these demands, there is a toner by a polymerization method.

On the other hand, in the polymerization method including the polymerization method toner, the viscosity of the polymerization reaction system increases as the polymerization proceeds, and the transfer of radicals and polymerizable monomers becomes difficult. Liable monomer components tend to remain. Particularly, in the case of a suspension polymerization method toner, components that may inhibit a polymerization reaction such as a dye, a pigment (particularly, carbon black), a charge controlling agent, and a magnetic substance are contained in a polymerizable monomer system. Since it is present in a large amount other than in the body, unreacted polymerizable monomers are more likely to remain.

If the toner particles contain many components that act as a solvent for the binder resin as well as the polymerizable monomer, the fluidity of the toner is deteriorated to deteriorate the image quality, and the toner has an anti-blocking property. Causes a decline. In addition to the performance directly related to the toner, especially when an organic semiconductor is used as the photoconductor, it also accompanies the deterioration phenomenon of the photoconductor such as memory ghost and blurred image other than the fusion phenomenon of the toner on the photoconductor drum. May cause problems. In addition to the matters relating to the performance of the product, there is a problem that the polymerizable monomer component volatilizes during fixing and emits an offensive odor.

[0010] In order to improve the above, as disclosed in JP-A-7-92736, the residual amount of the polymerizable monomer present in the toner particles is reduced to 500 ppm or less, thereby further improving the image quality. It has been proposed to produce an improvement effect.

Further, miniaturization of copiers, printers, etc.
With the personalization, the restrictions on the apparatus have increased, the burden on the above-mentioned problems has increased, and the concern for the environment has also increased, and the residual amount of the polymerizable monomer present in the toner particles has been reduced to 100 ppm or less. Preferably.

The residual amount of the polymerizable monomer in the toner particles is 1
As a method for reducing the content to 00 ppm or less, a known polymerizable monomer consumption promoting means used when a binder resin is produced by a polymerization method can be used. For example, as a method of removing the unreacted polymerizable monomer, a method of washing with a highly volatile organic solvent that does not dissolve the toner binder resin but dissolves the polymerizable monomer and / or the organic solvent component; A method of washing with an acid or an alkali; a solvent component that does not dissolve a foaming agent or a polymer is put into a polymer system, and the resulting toner is made porous to reduce the volatilization area of the internal polymerizable monomer and / or organic solvent component. Increasing method; and method of volatilizing main synthetic monomer and / or organic solvent component under dry conditions. Elution of toner components due to deterioration of toner encapsulating property, and selection of solvent such as persistence of the solvent. Therefore, a method of volatilizing a polymerizable monomer and / or an organic solvent component under dry conditions is most preferable.

Conventionally, the toner particles after solid-liquid separation of the suspension after the polymerization reaction are generally dried using a fluidized bed dryer or a vacuum dryer.

The drying of toner particles by a fluidized bed dryer proposed in JP-A-4-311966 and JP-A-8-179562 is a direct contact with a hot air flow, so that the toner is efficiently dried. Can be dried. However, because the particles come into contact with each other in a floating and flowing state,
Particles are very easily charged, causing adhesion to the wall surface of the flow chamber and the bag filter, etc., so that it is impossible to collect all of the particles after the treatment.

Further, Japanese Patent Application Laid-Open No. 8-160662 and the like have proposed a method of drying with a vacuum dryer. However, this drying method has an advantage that the object to be dried can be dried at a low temperature. However, since the inside of the apparatus is in a reduced pressure state, the gas phase stays, and the power for diffusing volatile components is significantly reduced. After evaporating and removing the unreacted polymerizable monomer, a very long drying time is required.

Japanese Patent Application Laid-Open No. 10-207122 proposes a method of vacuum-drying toner particles while injecting a gas. However, when a gas is introduced under vacuum, a sharp temperature drop occurs due to adiabatic expansion.If the gas is not temperature-controlled by heating or the like, the gas acts as a cooling agent due to the effect as a carrier gas. As a result, the drying efficiency is reduced. For this reason, it is difficult for the product temperature to rise to the set heating temperature, and a large difference occurs between the jacket temperature and the product temperature as described in the embodiment of the publication. In addition, since the temperature of the room temperature, the temperature around the drying device, and the temperature of the air flow injected are affected by the degree of vacuum, it is very difficult to control the product temperature.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner manufacturing method and a manufacturing system which solve the above-mentioned problems.

More specifically, an object of the present invention is to uniformly and efficiently remove unreacted polymerizable monomers from toner particles obtained by a polymerization method and to easily control the temperature of a dried product. It is an object of the present invention to provide a toner manufacturing method and a manufacturing system.

Another object of the present invention is to provide a method and system for producing a toner capable of obtaining a high-quality image without image defects caused by residual polymerizable monomers.

[0020]

According to the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles. After being washed and dehydrated, the obtained wet colored polymer particles are put into a dryer capable of being depressurized, and a temperature-controlled gas,
Preferably, the difference (AB) between the gas temperature A and the heating temperature B is-
10 ° C <(AB) <+ 5 ° C, more preferably -5 ° C
<(A−B) <+ 2 ° C. The drying under reduced pressure is performed while supplying a gas whose temperature is controlled so as to satisfy the condition, and the aqueous dispersion medium is substantially removed and remains in the colored polymer particles. The present invention relates to a method and system for producing a toner, wherein toner particles are obtained by removing the residual amount of a polymerizable monomer to 100 ppm or less.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a fluidized bed dryer used in a conventional method for producing a polymerized toner, particles come into contact with each other in a floating / flowing state. Adhesion may occur on bag filters. Furthermore, the particles adhering to the wall surface of the fluidized chamber are peeled off in a lump state, and as a whole, the removal of the polymerizable monomer becomes uneven, or it becomes impossible to collect the entire amount after the treatment. Had a problem. In addition, when the toner is externally added to the toner in a later step, the external additive does not uniformly adhere to the toner surface when the toner is externally added in a lump, which causes a problem in the performance as a developer. I was

When a reduced-pressure drier is used, as described above, since the inside of the apparatus is in a reduced-pressure state, the gas phase stays and the ability to diffuse volatile components is significantly reduced.
After evaporating and removing water, there is a problem that an extremely long drying time is required to further remove unreacted polymerizable monomers.

In order to solve this problem, even if a carrier gas is fed into the apparatus, if the temperature of the gas is not controlled by heating or the like, the temperature of the gas having a sharp drop due to adiabatic expansion is increased. As a result, the heat supplied from the heating source is taken away, and the drying efficiency is greatly reduced.

When the carrier gas is not supplied, that is, when the heat transfer from the heating surface is mainly performed, the smaller the temperature difference between the heating surface and the material temperature is, the smaller the heat transfer amount becomes.
Finally, the product temperature rises to near the heating temperature. However, if the temperature of the gas is not controlled, it is difficult for the product temperature to rise to near the set heating temperature, and a large difference occurs between the product temperature and the heating temperature. In addition, since the temperature of the room temperature, the temperature around the drying device, and the temperature of the gas to be injected depend on the degree of vacuum, there has been a problem that it is very difficult to control the product temperature.

Then, the present inventors have conducted intensive studies and as a result,
A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles, which are then washed and dehydrated, and the obtained wet The colored polymer particles are charged into a dryer capable of reducing pressure, and a temperature-controlled gas, preferably a difference (A−B) between the gas temperature A and the heating temperature B of the dryer is −10 ° C. <(A− B) <+ 5 ° C,
More preferably, a temperature-controlled gas is supplied so as to satisfy the condition of −5 ° C. <(A−B) <+ 2 ° C. (In most cases, since the jacket temperature is higher than room temperature, the temperature is controlled by heating.) By performing the drying under reduced pressure, heat is also transferred from the gas to be dried to the object to be dried, and the indirect heating from the jacket and the direct heating from the gas are performed (the effect becomes more remarkable when the gas supply amount increases). ), The aqueous dispersion medium can be substantially removed very efficiently, and the residual amount of the polymerizable monomer remaining in the colored polymer particles can be removed to 100 ppm or less. I found it.

Further, in most cases, it has been found that the temperature of the product can be easily increased to approximately the same temperature as the heating temperature, so that the temperature of the product can be easily controlled.

Hereinafter, the present invention will be described in more detail.

In the toner production method of the present invention, the polymerizable monomer composition is polymerized to produce colored polymer particles, which are then washed and dehydrated, and the obtained colored polymer particles are used as a dry raw material. Use a flash dryer that can instantaneously remove moisture in order to avoid a decrease in the degree of vacuum due to the vapor pressure at the time of evaporation of the moisture and to omit the time for moisture removal and shorten the time for vacuum drying. The moisture content may be reduced to 5% or less in advance.

The water content as used herein means the water content based on mass,
That is, the total weight (sum of dry toner weight and water weight)
Refers to the ratio of the mass of water to the water content, and was determined by a weight loss method at 105 ° C.

The vacuum dryer used in the present invention can be used without particular limitation as long as it is a heat transfer type having an external heating source and can dry colored polymers in a vacuum (= reduced pressure) state. However, for example, a reduced-pressure drying system having an embodiment as shown in FIG. 1 is preferable.

In the vacuum drying system shown in FIG. 1, first, a sample is put into the dryer main body 1, and a heating source such as hot water and steam flows into a jacket 4 attached so as to cover the apparatus. To heat the sample inside.

At this time, the sample is stirred by the stirring blade 5 in order to efficiently transfer heat to the entire sample.

Since the inside of the dryer is depressurized by the depressurizing pump 8 so that the sample is not damaged by heating, the boiling point of the volatile component is lowered and drying at a low temperature becomes possible.

Further, the gas generated by the gas generator 10 is sent into the apparatus as a carrier gas in order to prevent stagnation of volatile components due to the reduced pressure state. Since the temperature is measured and detected by the control device 15, and at the same time, the gas temperature controller 9 is controlled so that there is no difference between the set heating temperature and the gas temperature,
It is possible to dry without reducing efficiency.

As used herein, the term "gas temperature" refers to the temperature of a decompressed gas just before or after entering a depressurized vessel, and is measured immediately before entry or in the gas phase or exhaust pipe at the top of the vessel. Is preferably performed, but the measurement position is not limited thereto.

The in-machine pressure gauge 14 and the gas flow meter 17
Is detected by the controller 16 and at the same time, the gas flow controller 13 is used to prevent an excessive increase in the internal pressure due to the carrier gas / vapor vapor pressure and an increase in the pressure loss of the bag filter attached to the pressure reducing line. By controlling the gas flow rate at, the drying can be performed safely and efficiently.

Specific examples of the reduced-pressure dryer preferably used in the present invention include a Nauter mixer (manufactured by Hosokawa Micron), a ribocorn (manufactured by Okawara Seisakusho), and an SV mixer (manufactured by Shinko Pantech).

The gas used in the present invention is preferably a nonflammable gas such as nitrogen, argon, air, etc. in consideration of heating to near the jacket temperature.

The means for heating the gas in the present invention includes heating by a burner and heating by a steam heater, but is not particularly limited. However,
A gas temperature A to be supplied and a heating temperature B to be heated so as not to cause a difference from the set heating temperature are detected, and A and B are set to the following conditions: -10 ° C <(AB) <+ 5 ° C, preferably -5 ° C. It is more preferable that the system is controlled as shown in FIG. 1 so as to satisfy the following condition: ° C <(AB) <+ 2 ° C.

In the present invention, when a vacuum dryer as shown in FIG. 1 is preferably used, the supply position of the gas is not particularly limited, and the bottom of the device, the side of the device, the top of the device, or the stirring blade. Supply from any of them.

Although the heating method in the present invention is not particularly limited, a jacket-type can body attached around the container is attached, a heat source such as hot water or steam is passed through the inside, and the transfer from the heat source is performed. It is more preferable to use an indirect heating method in which the inside is heated by heat.

The heating temperature is the temperature of the heat source,
If it has a jacket, it is the temperature of the heat source passing through the inside, and is preferably 50 ° C. or less, preferably 40 ° C. or less in order to prevent a decrease in performance such as agglomeration and fusion of the material to be dried. Further, the pressure in the dryer is preferably maintained at 13 kPa or less so as not to lower the drying efficiency. If the vapor pressure due to the volatile matter of the material to be dried occurs, the gas supply amount is reduced or the supply is stopped. Is preferred. Also, the gas supply amount and the internal pressure are detected as shown in FIG.
It is more preferable that the gas supply amount can be controlled as a system so that the internal pressure of the dryer is 13 kPa or less.

Next, the toner obtained by the present invention is:
In order to faithfully develop finer latent image dots for higher image quality, the toner also has a finer particle diameter, specifically, a mass average diameter measured by a Coulter counter of 3 to 10 μm.
m is preferred. In the case of a toner having a mass average diameter of less than 3 μm, the cohesive force becomes too strong, so that the fluidity is reduced, the drying efficiency is reduced, and the unreacted polymerizable monomer cannot be reduced uniformly. . Further, due to poor transfer efficiency, a large amount of untransferred toner is generated on the photoreceptor or the intermediate transfer member, which causes non-uniform unevenness of an image due to fog or poor transfer. On the other hand, the toner has a mass average diameter of 10 μm.
If it exceeds m, fusion to the member is likely to occur,
As a result, image characteristics are degraded.

Next, in the production method of the present invention, a polymerized toner obtained by polymerizing a polymerizable monomer is used as a raw material.

In the present invention, a so-called seed polymerization method in which a monomer is further adsorbed onto the polymer particles once obtained and then polymerized using a polymerization initiator can also be suitably used in the present invention.

The polymerizable monomers usable in the above-mentioned polymerized toner include styrene monomers such as styrene, o (m-, p-)-methylstyrene and m (p-)-ethylstyrene; Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) acryl (Meth) acrylate monomers such as behenyl acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) Vinyl monomers such as acrylonitrile and acrylamide are preferably used. In addition, two or more kinds may be preferably used in combination as needed. These can be used alone or in general in the published Polymer Handbook, 2nd edition III-P139-
192 (manufactured by John Wiley & Sons) is used by appropriately mixing monomers so that the theoretical glass temperature (Tg) 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 this case, the color mixture of each color toner is insufficient and the color reproducibility is poor, and the transparency of the OHP image is remarkably reduced, which is not preferable from the viewpoint of high image quality.

In the toner according to the present invention, it is particularly preferable that a polar resin is further added in addition to the outer shell resin in order to incorporate a low softening point substance into the outer shell resin. As the polar resin used in the present invention, styrene and (meth)
Acrylic acid copolymer, maleic acid copolymer, saturated polyester resin and epoxy resin are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with a shell resin or a monomer in the molecule. When a polar resin having an unsaturated group is contained, a cross-linking reaction occurs with the monomer forming the outer shell resin layer, and as a full-color toner, it becomes extremely high in molecular weight and disadvantageous for color mixing of four-color toner, which is not preferable. .

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

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, 166, 169, 177, 18
4, 185, 202, 206, 220, 221, 254
Is 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. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The colorant is used in an amount of 1 to 20 parts by mass per 100 parts by mass of the resin.

When a magnetic material is used as a black colorant, unlike other colorants, 40 parts by mass of resin is used.
１５０150 parts by mass are used.

The charge control agents used in the present invention include:
A known charge control agent can be used, but a charge control agent which is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is preferable. Further, in the case where a direct polymerization method is used in the present invention, a charge control agent having no polymerization inhibitory property and having no solubilized substance in an aqueous system is particularly preferable. Specific compounds include:
Metallic compounds of salicylic acid, naphthoic acid, and dicarboxylic acid, sulfonic acid, high molecular compounds having carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, and carricks arenes can be used as the negative type. A quaternary ammonium salt, a high molecular compound having the quaternary ammonium salt in a side chain, a guanidine compound, an imidazole compound and the like are preferably used. The charge control agent is resin 10
0.5 to 10 parts by mass relative to 0 parts by mass is preferred. However, in the present invention, the addition of a charge control agent is not essential, and in the case of using a two-component developing method, frictional charging with a carrier is used, and even in the case of using a non-magnetic one-component blade coating developing method, a blade is used. By positively utilizing frictional charging with the member or the sleeve member, it is not necessary to necessarily include a charge control agent in the toner.

Examples of the polymerization initiator that can be used in the polymerization toner according to the present invention include, for example, 2,2′-azobis- (2,
4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-
Azo or diazo polymerization initiators such as methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl A peroxide-based polymerization initiator such as peroxide is used. The amount of the polymerization initiator varies depending on the desired degree of polymerization, but is generally used in an amount of 0.5 to 20% by mass based on the monomer. The type of the polymerization initiator varies slightly 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 degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like can be further added and used.

In the polymerized toner according to the present invention, especially when suspension polymerization using a dispersant is used, the dispersant used may be an inorganic compound such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, or zinc phosphate. , Calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina and the like. As organic compounds, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose,
Polyacrylic acid and its salts, starch and the like can be used by dispersing them in an aqueous phase. These stabilizers include polymerizable monomers 10
It is preferable to use 0.2 to 20 parts by mass with respect to 0 parts by mass.

When an inorganic compound is used among these stabilizers, a commercially available one may be used as it is, but in order to obtain fine particles, the inorganic compound may be formed in a dispersion medium. For example, in the case of tricalcium phosphate, an aqueous sodium phosphate solution and an aqueous calcium chloride solution may be mixed under high stirring.

In order to finely disperse these stabilizers, 0.001 to 0.1 parts by mass of a surfactant may be used. This is to promote the expected action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate,
Examples include sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like.

In the toner manufacturing method of the present invention, a toner can be specifically manufactured by the following manufacturing method.

That is, 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 by a homogenizer, an ultrasonic disperser or the like. Alternatively, the dispersed monomer system is dispersed in an aqueous phase containing a dispersion stabilizer using a conventional stirrer, CLEARMIX, homomixer, homogenizer, or the like. Preferably, the agitation speed and time are adjusted so that the monomer droplets have the desired size of the toner particles, and granulation is performed. After that, due to the action of the dispersion stabilizer, the particle state is maintained,
In addition, stirring may be performed to such an extent that settling of particles is prevented.
The polymerization is preferably performed 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 further, in order to remove unreacted polymerizable monomers and by-products which cause odor at the time of fixing the toner, the second half of the reaction, or the end of the reaction. Later, a part of the aqueous medium may be distilled off. After completion of the reaction, the generated toner particles are collected by washing and filtration, and dried by the drying method of the present invention.
In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

The water content of the toner of the present invention was measured using MA4
0 It was determined by an electronic moisture meter (manufactured by Sartorius) by a weight loss method at 105 ° C.

The remaining amount of the polymerizable monomer and the organic solvent remaining in the toner particles was determined by dissolving 0.3 g of the toner in 10 g of acetone, using a ultrasonic shaker for 30 minutes, The sample was allowed to stand for a day and then filtered through a 0.5 μm filter, and each was measured by gas chromatography under the following conditions by the absolute calibration curve method.

G. C. Conditions Measuring device: HEWLETT PACKARD HP68
90 series capillary column: (25 mx 0.2 mm, HP-IN
NOWAX, film thickness: 0.4 μm) Detector: FID He flow rate 25 ml / min Injection temperature: 200 ° C. Detector temperature: 250 ° C. Column temperature: Raised from 50 ° C. at a rate of 10 ° C./min for 15 minutes Implanted sample volume: 2 μl

The particle size distribution of the toner can be measured by various methods. In the present invention, the measurement was performed using a Coulter counter.

As a measuring device, Coulter Counter T
A-II type (manufactured by Coulter), number average distribution,
Interface to output mass average distribution (made by Nikkaki)
And CX-1 personal computer (manufactured by Canon)
And the electrolyte is 1% N using 1st grade sodium chloride.
An aqueous aCl solution is prepared.

The measuring method is as follows.
In 50 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added.

The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and a 100 μm aperture was used as the aperture by the Coulter Counter TA-II. The particle size distribution of the particles is measured, and various values are determined therefrom.

[0069]

The present invention will be specifically described below with reference to examples.

The capacity of the dryer is the volume up to the heat transfer surface which can be heated by the heat source.

<Example 1> 450 parts by mass of a 0.1 mol / l-Na ₃ PO ₄ aqueous solution was added to 710 parts by mass of ion-exchanged water, heated to 60 ° C, and then mixed with Clearmix (M.
(Manufactured by Technic) at 3,500 rpm. To this, 68 parts by mass of a 1.0 mol / liter CaCl ₂ aqueous solution was added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

On the other hand, the dispersoid system includes: styrene monomer 170 parts by mass n-butyl acrylate 30 parts by mass I. Pigment Red 122 10 parts by mass-Saturated polyester 20 parts by mass-Metal salicylate compound 3 parts by mass-Ester wax 25 parts by mass I. Pigment Red 122, 100 parts by mass of a metal salicylate compound and a styrene monomer are dispersed for 3 hours using an attritor (manufactured by Mitsui Miike Kakoki Co., Ltd.).
A colorant dispersion was obtained. Next, the rest of the above formulation was added to the colorant dispersion, heated to 60 ° C., and dissolved and mixed for 30 minutes. To this, 10 parts by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved to prepare a polymerizable monomer composition.

The 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 80 ° C., and polymerization was performed at 50 revolutions / minute.
Continued for hours. Next, an internal temperature of 80 ° C. and an internal pressure of 4
The distillation was performed for 4 hours under the condition of 7.3 kPa. After distillation, the slurry was cooled, diluted hydrochloric acid was added, and Ca ₃ (P
After dissolving O ₄ ) ₂ , filtration, washing with water, and crushing were performed to obtain wet colored polymer particles having a water content of 20% and a mass average diameter of 7.2 μm.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 650 ppm.

30 kg of the obtained wet colored polymer particles
Was dried using a reduced-pressure drying system shown in FIG. 1 having a capacity of 100 liters.

The drying conditions were as follows: jacket temperature 45
1 ° C., using nitrogen as the gas, and detecting the temperature in the jacket and the temperature of nitrogen as shown in FIG.
While the temperature was controlled so as to obtain a flow rate of 600 L / hr into the apparatus.

About 3.5 hours after the start of drying, the temperature of the dried product reached 45 ° C., and 5 hours after the end of the drying, the product temperature was 45.2 ° C., which was almost equal to the temperature in the jacket.

The internal pressure of the dryer reached a maximum of 5 kPa, and was 2 kPa after about 1 hour. The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate.
Since it did not exceed 3 kPa, the flow rate was 600 L
/ Hr.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 70 ppm. To 100 parts by mass of the obtained toner, 1.5 parts by mass of hydrophobic silica having a specific surface area of 200 m ² / g by a BET method was externally added to prepare a developer.

Using this developer, a color laser jet printer manufactured by Canon Inc.
When an image output test was performed in an environment of 23 ° C./65% RH using a modified 2030 machine, the image density did not change between the initial and the endurance even at 5,000 sheets, and the image density was high without dropout. A picture of image quality 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. Further, when an image was formed on the OHP sheet, an image having good transparency was obtained.

A similar image-drawing test was performed in an environment of 30 ° C./80% RH, and similar results were obtained.

<Example 2> Until crushing, the wet colored polymer particles obtained in the same manner as in Example 1 were subjected to the same system as in Example 1 except that the nitrogen temperature for feeding was controlled at 45 ° C. Drying under reduced pressure was performed under the same conditions. Also, the dryer internal pressure is
It reaches up to 5kPa at the maximum and 2kPa after about 1.0hr
Met. The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained the same as in Example 1.

About 3.0 hours after the start of drying, the temperature of the dried product reached 45 ° C., and 5 hours after the end of the drying, the product temperature was 45.6 ° C., which was almost equal to the temperature in the jacket.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 40 ppm. The obtained toner was used as a developer by performing the same operation as in Example 1 below. Further, the same image formation evaluation as in Example 1 was performed, and the same image formation result as in Example 1 was obtained.

<Example 3> Until the disintegration, the wet colored polymer particles obtained in the same manner as in Example 1 were fed with the same system and method as in Example 2 except that the nitrogen flow rate was 1200 L / hr. Vacuum drying was performed under the conditions.

About 2.5 hours after the start of drying, the temperature of the dried product reached 45 ° C., and 5 hours after the completion of the drying, the product temperature was 45.8 ° C., which was almost equal to the temperature in the jacket.

The internal pressure of the dryer is 6.2 kPa at the maximum.
And reached 2.26 kPa after about 0.6 hr. The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained at 1200 L / hr.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 20 ppm.

The obtained toner was subjected to the same operation as in Example 1 to obtain a developer. Further, the same image formation evaluation as in Example 1 was performed, and the same image formation result as in Example 1 was obtained.

<Example 4> Until crushing, the wet colored polymer particles obtained in the same manner as in Example 1 were subjected to preliminary drying as a continuous flash dryer (flash jet drier F).
JD-4: manufactured by Seishin Enterprise Co., Ltd.).

As drying conditions, air at 80 ° C.
m ³ / hr to blow the colored polymer particles at 10 kg / h
It was fed continuously at r.

At this time, the water content was 0.2%, and the amount of the polymerizable monomer remaining in the toner particles was 635 ppm.

30 kg of the obtained wet colored polymer particles
Was dried under vacuum in the same system and under the same conditions as in Example 2.

The internal pressure of the dryer was set to 2.
The pressure became 0 kPa, and the internal pressure was maintained until the drying was completed.

The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained at 600 L / hr.

[0096] The dried product temperature reached 45 ° C about 1.8 hours after the start of drying, and after 5 hours from the end of the drying, the product temperature was 46.0 ° C, which was almost equal to the temperature in the jacket.

At this point, the amount of the polymerizable monomer remaining in the toner particles was 20 ppm.

The obtained toner was subjected to the same operation as in Example 1 to obtain a developer. Further, the same image formation evaluation as in Example 1 was performed, and the same image formation result as in Example 1 was obtained.

<Example 5> Until crushing, about 15 kg of the wet colored polymer particles obtained in the same manner as in Example 2 was weighed using a 50-liter ribocorn vacuum dryer (Model RD-50:
(Okawara Seisakusho), and dried by applying the system used in FIG.

The drying conditions are as follows:
As shown in FIG. 2, temperature and nitrogen temperature were detected, and nitrogen was used as a gas, and the gas was fed into the apparatus at a flow rate of 300 L / hr while controlling the temperature to 45 ° C.

About 2.7 hours after the start of drying, the temperature of the dried product reached 45 ° C., and 5 hours after the end of the drying, the product temperature was 45.4 ° C., which was almost equal to the temperature in the jacket.

The internal pressure of the dryer reached 5.5 kPa at the maximum, and was 2.0 kPa after 0.8 hr.

The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained at 300 L / hr.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 40 ppm.

The obtained toner was subjected to the same operation as in Example 1 to obtain a developer. Further, the same image formation evaluation as in Example 1 was performed, and the same image formation result as in Example 1 was obtained.

<Example 6> Until crushing, the same system as in Example 2 was used except that the nitrogen flow rate at which the wet colored polymer particles obtained in the same manner as in Example 1 were fed was 6000 L / hr. Vacuum drying was performed under the same conditions.

About 2.0 hours after the start of drying, the temperature of the dried product reached 45 ° C., and 5 hours after the end of the drying, the product temperature was 46.0 ° C., which was almost equal to the temperature in the jacket.

Further, the operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate.
Although the momentum exceeded kPa, by controlling the flow rate,
It was able to be suppressed within 13 kPa. Also, about 0.5
After that, it calms down at about 6.5 kPa, and the nitrogen supply rate is 6 kPa.
000 L / hr was maintained.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 35 ppm.

The obtained toner was subjected to the same operation as in Example 1 to obtain a developer. Further, the same image formation evaluation as in Example 1 was performed, and the same image formation result as in Example 1 was obtained.

<Comparative Example 1> Until crushing, about 40 kg of the wet colored polymer particles obtained in the same manner as in Example 1 was used using a fluidized bed dryer (FBS-5: manufactured by Okawara Seisakusho). Drying was performed.

As the drying conditions, air at 50 ° C. was blown at a linear velocity of 0.4 m / sec, and drying was performed for 4 hours. The product temperature after drying was 47 ° C., and the water content was 0.1%. Further, the content of the polymerizable monomer remaining in the toner particles was 120 ppm, but lumps were generated due to toner aggregation.

Further, a toner adhesion layer was observed on the inner wall of the dryer. The adhesion layer of the toner was taken out, and the water content was measured. As a result, it was 0.1%. However, the content of the polymerizable monomer remaining in the toner particles was 280.
ppm.

The obtained toner was subjected to the same operation as in Example 1 to obtain a developer. Further, the same image output test as in Example 1 was carried out. As a result, solid white spots due to poor transfer occurred from about 1,500 sheets, and were exposed at about 4,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to fusion of the toner to the body.

<Comparative Example 2> Until crushing, about 30 kg of the wet colored polymer particles obtained in the same manner as in Example 1 was used, except that no nitrogen was fed and the gas flow rate and temperature were not controlled. Vacuum drying was performed under the same apparatus (same system) and the same conditions as in Example 1.

The internal pressure of the dryer reached 3.5 kPa at the maximum, and was 1.86 kPa after about 2 hours.

The drying temperature was 45 hours after the start of drying for about 3 hours.
° C, and 5 hours after the end of drying, the product temperature was 45.0 ° C, which was almost equal to the temperature in the jacket.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 290 ppm. The obtained toner was used as a developer by performing the same operation as in Example 1 below. Further, when an image forming test similar to that in Example 1 was performed, solid white spots due to transfer failure occurred from about 2,000 sheets, and the photosensitive area was exposed at about 4,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to fusion of the toner to the body.

<Comparative Example 3> Until crushing, about 30 kg of the wet colored polymer particles obtained in the same manner as in Example 1 was placed in a dryer at room temperature (= room temperature 20 ° C.) without heating with nitrogen. Except for feeding, drying under reduced pressure was performed under the same system and under the same conditions as in Example 1.

Even at the point of time 5 hours after the completion of drying, the product temperature was 33 ° C., which was far from the jacket temperature of 45 ° C.

The internal pressure of the dryer reached 4.0 kPa at the maximum, and was 2.0 kPa after 2.0 hours.

The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained at 600 L / hr.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 250 ppm. The obtained toner was used as a developer by performing the same operation as in Example 1 below. Further, the same image forming test as in Example 1 was carried out. As a result, solid white spots due to poor transfer occurred from about 3,500 sheets, and were exposed at about 5,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to fusion of the toner to the body.

<Comparative Example 4> Until crushing, about 30 kg of wet colored polymer particles obtained in the same manner as in Example 1 was placed in a dryer at room temperature (= room temperature 20 ° C.) without heating with nitrogen. Except for feeding, vacuum drying was performed under the same system and under the same conditions as in Example 3.

The internal pressure of the dryer reached 5.4 kPa at the maximum, and was 2.26 kPa after about 2.5 hours.

The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained at 1200 L / hr.

[0127] Even after 5 hours from the end of the drying, the product temperature was 31 ° C, which was far from the jacket temperature of 45 ° C.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 270 ppm. The obtained toner was used as a developer by performing the same operation as in Example 1 below. Further, the same image forming test as in Example 1 was carried out. As a result, solid white spots due to poor transfer occurred from about 3,500 sheets, and were exposed at about 5,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to fusion of the toner to the body.

<Comparative Example 5> Until crushing, the same system as in Example 2 except that the nitrogen temperature at which the wet colored polymer particles obtained in Example 1 were fed was controlled at 60 ° C. -Vacuum drying was performed under the same conditions.

The internal pressure of the dryer reached a maximum of 5 kPa, and was 2.2 kPa after about 1.0 hr. The operation was performed while simultaneously detecting the internal pressure and the nitrogen flow rate. However, since the internal pressure did not exceed 13 kPa, the flow rate remained the same as in Example 2.

In about 2.0 hours after the start of drying, the temperature of the dried product reaches 45 ° C., and 5 hours after the end of the drying, the product temperature becomes 52 ° C.
Met.

At this time, the amount of the polymerizable monomer remaining in the toner particles was 20 ppm, but the dried product had many lumps.

The obtained toner was subjected to the same operation as in Example 1 to obtain a developer. Further, the same image output test as in Example 1 was carried out. As a result, solid white spots due to poor transfer occurred from about 1,500 sheets, and were exposed at about 4,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to fusion of the toner to the body.

The drying conditions and results obtained in Examples and Comparative Examples are summarized below.

[0135]

[Table 1]

[0136]

As described above, according to the present invention, unreacted polymerizable monomers remaining in the aqueous dispersion medium and the toner particles are uniformly and quickly removed from the toner particles obtained by the polymerization method. And further increasing the temperature of the dried product to a temperature substantially equal to the temperature in the jacket (= heating temperature). Therefore, it is possible to provide a method for producing a toner that can easily control the temperature of the product. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a system of an apparatus for drying an object to be dried under reduced pressure while feeding a gas whose temperature is controlled, used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dryer main body 2 Thermometer (for measuring product temperature) 3 Thermometer (for measuring gas temperature) 4 Jacket 5 Stirrer 6 Bag filter 7 Condenser 8 Decompression pump 9 Gas temperature controller 10 Gas generator 11 Sample outlet 12 Temperature Meter {for measuring jacket internal temperature (= heating temperature)} 13 Gas flow controller 14 In-machine pressure gauge 15 Jacket temperature / gas temperature detection and control device 16 In-machine pressure / gas flow detection and control device 17 Gas flow meter

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinori Tsuji 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H005 AB06 AB09 EA03 EA07

Claims (7)

[Claims] 1. A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles, which are then washed and dehydrated. The obtained wet colored polymer particles are put into a dryer capable of being depressurized, and dried under reduced pressure while supplying a temperature-controlled gas, to remove water, and further remaining in the colored polymer particles. A method for producing a toner, characterized in that toner particles are obtained by removing the remaining amount of a polymerizable monomer to 100 ppm or less. 2. The difference (A−B) between the gas temperature A of the temperature-controlled gas and the heating temperature B of the dryer satisfies the following relationship: −10 ° C. <(AB) <+ 5 ° C. The method for producing a toner according to claim 1, wherein: 3. The difference (A−B) between the gas temperature A of the temperature-controlled gas and the heating temperature B of the dryer satisfies the following relationship: −5 ° C. <(AB) <+ 2 ° C. The method for producing a toner according to claim 1, wherein: 4. The drying under reduced pressure is performed by setting the pressure in the dryer to 13 kP.
The method for producing a toner according to claim 2, wherein the gas is supplied in an amount to be kept equal to or less than a. 5. A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles, which are then washed and dehydrated. A system for drying the obtained wet colored polymer particles under reduced pressure while supplying a temperature-controlled gas, and detects a supplied gas temperature A and a heating temperature B of a dryer for heating the wet colored polymer particles. And a drying system under reduced pressure while controlling the temperature so that A and B satisfy the following condition: −10 ° C. <(AB) <+ 5 ° C. 6. The method according to claim 5, wherein drying is performed under reduced pressure while controlling the temperature so that A and B satisfy the following condition: −5 ° C. <(AB) <+ 2 ° C. system. 7. The toner production system according to claim 5, wherein the gas supply amount and the internal pressure are detected, and the gas supply amount is controlled so that the internal pressure of the dryer becomes 13 kPa or less. .