JPH10207122A - Manufacturing method of toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing a toner which is excellent in environmental safety with little residual polymerizable monomer, volatile polymerization catalyst decomposition product and the like. SOLUTION: Styrene-butyl acrylate copolymer particles containing carbon black are placed in a container of a vacuum dryer, the pressure is set to 30 torr, the jacket temperature is set to 50 ° C., and nitrogen gas is injected at 5 l / min, and the pressure is set to 35 torr.
The silica particles and the organic fine particles obtained by subjecting the dried polymer particles to a hydrophobic treatment are put into a Henschel mixer, and the silica particles and the organic fine particles are adhered to the polymer particles. 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 more particularly, to a method for efficiently producing a toner excellent in environmental safety with little residual polymerizable monomer and volatile polymerization initiator decomposition products. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image formed in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus is first developed with toner, and then the formed toner image is used as required. After being transferred onto a transfer material such as paper, it is fixed by various methods such as heating, pressing, and solvent vapor.

An image formed by an image forming apparatus is
Every year, the demand for its definition is increasing. Conventionally, the toner used in the apparatus is a pulverized toner obtained by melting, pulverizing, and classifying a resin containing a colorant or the like, but the particle size control is easy, and complicated production such as classification is required. Attention has been paid to polymerization toners, which are said to require no steps.

In general, a colorant-containing polymer particle is obtained by polymerizing a monomer such as styrene by a method such as suspension polymerization, emulsion polymerization, or dispersion polymerization (further kneading and pulverizing in a pulverization method). Obtainable. Since it is difficult to polymerize the monomer at 100%, a small amount of unreacted polymerizable monomer or volatile compound remains in the colorant-containing polymer particles for toner particles.

When an unreacted polymerizable monomer or a volatile compound is used in an electrostatic image forming apparatus,
The remaining unreacted polymerizable monomers and the like volatilize out of the toner particles due to heating during transfer or the like, thereby deteriorating the environment around the image forming apparatus.

[0006] For this reason, conventionally, when the polymer particles are in a suspension, an emulsion or the like, a steam stripping treatment or the like is performed to remove the residual polymerizable monomer. However, even when steam stripping is performed, about 100 ppm of a polymerizable monomer or the like remains.
In steam stripping, polymer particles undergo thermal aggregation by heating, and the particle size distribution is widened. Furthermore,
When heat coagulation proceeds, it may be blocked.

[0007] In addition, unreacted polymerizable monomers and volatile compounds are removed together with water by heating and drying the colorant-containing polymer particles formed by the polymerization method. For drying, a spray drier, a fluidized bed drier, and a tray type drier are used. In these dryers, it is necessary to send hot air at a temperature near the boiling point of water in order to evaporate water, and therefore, thermal aggregation of the colorant-containing polymer particles occurs, and the particle size distribution is widened.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently producing a toner which is low in residual polymerizable monomers and decomposition products of volatile polymerization catalysts, is excellent in environmental safety and is efficient. It is in. In vacuum equipment such as a vacuum dryer (excluding special equipment such as CVD), how to increase the degree of vacuum by reducing pressure, for example, how to increase airtightness so that gas does not leak into a container That was being considered by researchers. Therefore, it was not conceivable to drop the degree of vacuum. We have:
As a result of diligent research to achieve the above object, the inventors have found that the above object can be achieved by vacuum-drying the colorant-containing polymer particles while injecting a gas such as nitrogen. Was completed.

[0009]

Thus, according to the present invention, there is provided a method for producing a toner, comprising the steps of (1) vacuum-drying colorant-containing polymer particles while injecting a gas.

The following are provided as preferred embodiments of the present invention. (2) The method according to (1), wherein the gas is a nonflammable gas. (3) The method according to (1), wherein the gas is air or nitrogen.

(4) The above-mentioned (1) to (3), wherein the coloring agent can be colored black, magenta, yellow or cyan.
Manufacturing method. (5) The method according to any one of (1) to (4), wherein the polymer particles are made of a copolymer containing a styrene monomer and an ethylenically unsaturated carboxylic acid ester monomer as monomer units. Method.

(6) The polymer particles have a monomer unit as
The method of the above-mentioned (5), further comprising a crosslinking monomer. (7) The method according to (5) or (6), wherein the polymer particles further contain a macromonomer as a monomer unit.

(8) Vacuum drying is performed at a pressure of 1 to 200 torr.
r, preferably 2-100 torr, jacket temperature 20
(1) to (80), preferably 25 to 60 ° C
The manufacturing method of (7). (9) Vacuum drying is performed when the colorant-containing polymer particles have a product temperature of 50.
(1) to (C), preferably 35 ° C or lower.
The manufacturing method of (8).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a toner according to the present invention is characterized in that the step of drying the colorant-containing polymer particles includes a step of vacuum drying while injecting a gas.

[0015] In the present invention, the vacuum drying is a method in which an object to be dried is placed in a container, the inside of the container is depressurized, the boiling point or the sublimation point of a volatile component such as water in the object to be dried is lowered, and the object is evaporated or sublimated. The steam is dried by being condensed and removed by a condenser communicating with the container.

In vacuum drying, the pressure is usually 1 to 2
00 torr, preferably 2 to 100 torr, more preferably 2 to 70 torr. When the pressure is high, the evaporation of volatiles decreases, and the drying efficiency decreases.

In vacuum drying, the jacket temperature is usually 20 to 80 ° C, preferably 25 to 60 ° C. If the jacket temperature is high, thermal aggregation of the polymer particles tends to occur. If it is low, the drying speed will be low. The jacket temperature refers to a temperature of a heating element attached around or inside the container for heating the inside of the container of the dryer.

Further, in the present invention, the temperature of the colorant-containing polymer particles during vacuum drying may be important. That is, in the present invention, the product temperature is preferably set to 50 ° C or lower, more preferably 35 ° C or lower. When the product temperature increases, the colorant-containing polymer particles tend to agglomerate and fuse together. Here, the product temperature is the temperature of the polymer particles themselves, and specifically, is the value obtained by inserting a thermometer into the polymer particles contained in the dryer.

In the present invention, the colorant-containing polymer particles may be vacuum-dried while being left standing in the dryer.
It is preferable to stir to promote evaporation or sublimation of volatile components.

In the present invention, the vacuum dryer preferably used is a material-stationary vacuum dryer such as a box type (shelf-stage type) or a manifold type; a mechanical type such as a tunnel type, a belt type, a roll type, or a drum type. Conveying vacuum device; cylinder (groove)
A mechanical stirring type vacuum device such as a stirring type, a cylindrical rotation type, and a special rotation type may be used. Of these, a cylindrical (groove) stirring type vacuum drying apparatus is preferably used. More specifically, examples of the vacuum dryer include a commercially available SV mixer manufactured by Shinko Pantech Co., Ltd., particularly, a T series such as SV-001VT, or a conical blender dryer manufactured by Nippon Dryer Co., Ltd.

In the present invention, a gas is injected during vacuum drying. The gas used in the present invention generates an airflow in the vacuum dryer container. This gas stream makes it possible to efficiently remove the remaining polymerizable monomers and volatile compounds that remain. Specifically, air, helium, nitrogen, oxygen, carbon dioxide, hydrogen and the like can be mentioned. Of these, nonflammable gas is preferable from the viewpoint of preventing dust explosion, and air and nitrogen are preferable from the viewpoint of cost.

The amount of gas to be injected depends on the pressure in the vacuum dryer.
An amount that does not significantly increase from the above pressure range,
Specifically, the injection is carried out so that the pressure usually increases by 0.5 to 20 torr, preferably 1 to 10 torr. Gas injection can be intermittent or continuous.

The colorant-containing polymer particles used in the present invention are:
It is a particulate polymer containing a colorant.

Examples of the coloring agent include carbon black, titanium white, nigrosine base, aniline blue, calco oil blue, chrome yellow, ultramarine blue, orient oil red, phthalocyanine blue,
Dyes and pigments such as malachite green oxalate; magnetic particles such as cobalt, nickel, iron sesquioxide, iron tetroxide, iron manganese oxide, iron zinc oxide, and nickel iron oxide;

Further, as a colorant for a magnetic color toner, C.I. I. Direct Red 1 and 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I.
Modant Red 30, C.I. I. Direct Blue 1 and 2, C.I. I. Acid Blue 9 and 15, C.I. I. Basic Blue 3 and 5, C.I. I. Modant Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Greens 4 and 6 are pigments such as graphite, cadmium yellow, mineral first yellow, navel yellow,
Nephthol yellow S, Hansa yello G, permanent yellow NCG, tartrazine lake, red lead graphite, molybdenum orange, permanent orange GTR, pyrazolone orange, benzidine orange G, cadmium red,
Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmine 3B, Manganese Purple, Fast Violet B, Methyl Violet Lake, Navy Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue,
Fast Sky Blue, Indaslen Blue BC, Chrome Green, Chromium Oxide, Pigment Green B, Malachite Green Lake, Final Yellow Green G, and the like.

Examples of the magenta coloring pigment for full-color toner include C.I. I. Pigment Red 1 to 209, C.I. I.
Pigment Violet 19, C.I. I. Bat Red 1
To 35 etc. are magenta dyes such as C.I. I. Solvent Red 1-121, C.I. I. Disperse thread 9,
C. I. Solvent violet 8 to 27, C.I. I. Oil-soluble dyes such as Disperse Violet 1; I. Basic Red 1 to 40, C.I. I. Basic dyes such as Basic Violet 1 to 28 and the like,

Cyan color pigments for full-color toners include C.I. I. Pigment Blue 2 to 17, C.I. I. Bat Blue 6, C.I. I. Acid Blue 45 and a copper phthalocyanine pigment in which a phthalocyanine skeleton is substituted with 1 to 5 phthalimidomethyl groups.

The yellow color pigments for full-color toners include C.I. I. Pigment Yellow 1 to 138, C.I.
I. Bat yellow 1 to 20 and the like.

These dyes and pigments are generally used in a proportion of 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymer constituting the polymer particles. The magnetic particles are usually 1 to 100 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight of the polymer constituting the polymer particles.
Used in parts by weight.

The colorant-containing polymer particles may be produced by, for example, melt-kneading a resin, a colorant, and other additives, pulverizing the mixture, and classifying the mixture as necessary. A method of polymerizing a monomer in which an additive is dispersed,
And the like. Of these, the latter method of polymerization is preferred because it does not require time and effort such as classification, and can provide true spherical particles.

In the pulverizing method, a styrene- (meth) acrylate copolymer or polyester is usually used as the resin.

Examples of the method for polymerizing a polymerizable monomer in which a colorant or other additives are dispersed include an emulsion polymerization method, a suspension polymerization method, a precipitation polymerization method, and a dispersion polymerization method. In addition, a suspension polymerization method capable of easily obtaining a particle size suitable as a polymer particle for a toner is preferable.

In the polymerization method, the polymerization of the polymerizable monomer may be performed in one stage or may be performed in two stages. In the method of polymerizing in two stages, the type of the monomer to be polymerized in the first step and the type of the monomer to be polymerized in the second step are changed to soften the core particles formed in the first step, By hardening the shell formed by eye polymerization,
The balance between low-temperature fixability and high-temperature preservability can be improved.

As the polymerizable monomer, styrene monomers such as styrene, vinyltoluene and α-methylstyrene;
Acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
2-ethylhexyl acrylate, dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile,
Derivatives of acrylic acid or methacrylic acid such as acrylamide and methacrylamide; ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; vinyl acetate and vinyl propionate Vinyl esters such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; 2-vinyl pyridine;
Monovinyl monomers such as nitrogen-containing vinyl compounds such as 4-vinylpyridine and N-vinylpyrrolidone;
These monovinyl monomers may be used alone, or a plurality of monomers may be used in combination. Of these monovinyl monomers, styrene monomers or derivatives of acrylic acid or methacrylic acid, particularly styrene monomers and ethylenically unsaturated carboxylic acid esters, are preferably used.

It is preferable to use an arbitrary crosslinkable monomer together with these monovinyl monomers as a polymerizable monomer in order to improve the fixing property, particularly the offset property. Examples of the crosslinking monomer include, for example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; diethylenically unsaturated carboxylic esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N, N-divinylaniline; Divinyl ether; a compound having three or more vinyl groups; and the like. These crosslinkable monomers can be used alone or in combination of two or more. In the present invention, the crosslinking monomer
Usually, 0.1 part by weight based on 100 parts by weight of the monovinyl monomer.
It is desirable to use 1 to 5 parts by weight, preferably 0.3 to 2 parts by weight.

In the present invention, it is preferable to use a macromonomer together with a monovinyl-based monomer as a polymerizable monomer in order to improve the balance between storage stability and fixability. The macromonomer has a vinyl polymerizable functional group at the terminal of the molecular chain and has a number average molecular weight of usually 1,0.
00-30,000 oligomers or polymers. If the number average molecular weight is smaller than 1,000, the surface portion of the polymer particles becomes soft and the storage stability is reduced. Conversely, when the number average molecular weight is more than 30,000, the meltability of the macromonomer deteriorates, and the fixability decreases.

Examples of the vinyl polymerizable functional group at the terminal of the macromonomer molecular chain include an acryloyl group and a methacryloyl group, and a methacryloyl group is preferable from the viewpoint of easy copolymerization.

Specific examples of the macromonomer used in the present invention include polymers obtained by polymerizing styrene, styrene derivatives, methacrylates, acrylates, acrylonitrile, methacrylonitrile, etc., alone or in combination of two or more. Macromonomers having a polysiloxane skeleton, and those disclosed on pages 4 to 7 of JP-A-3-203746 can be exemplified.

The amount of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.1 to 100 parts by weight based on 100 parts by weight of the monovinyl monomer.
It is 0.5 to 1 part by weight. If the amount of the macromonomer is too small, the balance between the storability and the fixability is not improved. When the amount of the macromonomer is extremely large, the fixing property is reduced.

As polymerization auxiliary materials such as a polymerization initiator and a molecular weight modifier for polymerizing a monomer, and various additives such as a release agent and a pigment dispersant, those used in a usual polymerization method are used. Can be used.

As the polymerization initiator used in the present invention, those which are soluble in the monomers used can be used without particular limitation. More specifically, for example, methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxod, t-butyl peroxy-2ethyl hexaniate And peroxides such as di-iso-propylperoxydicarbonate and di-t-butyldiperoxyisophthalate; 2,2′-azobis (2,
Azo compounds such as 4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, and 1,1′-azobis (1-cyclohexanecarbonitrile). The oil-soluble polymerization initiator is a polymerizable monomer 1
0.1 to 20 parts by weight (and also 1 to 20 parts by weight)
10 parts by weight).

Examples of the molecular weight modifier optionally used in the present invention include t-dodecyl mercaptan, n
-Marcaptans such as dodecylmercaptan and n-octylmercaptan; and halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide. These molecular weight modifiers can be added to the reaction system before the start of the polymerization or during the polymerization. The molecular weight modifier is used in an amount of 0.01 to 1 based on 100 parts by weight of the polymerizable monomer.
It is preferable to use 0 parts by weight (more preferably 0.1 to 5 parts by weight).

The colorant-containing polymer particles used in the present invention may contain a release agent (wax), a charge control agent and the like in addition to the colorant.

Examples of the release agent used as required in the present invention include low molecular weight polyolefins such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene, and waxes. The release agent is used in an amount of 0.1 to 100 parts by weight of the polymerizable monomer.
It is preferable to use 20 parts by weight (more preferably 1 to 10 parts by weight).

In the present invention, if necessary, it is desirable to add a charge control agent for the purpose of improving the chargeability of the obtained toner. As such a charge control agent, it is possible to use various positively or negatively chargeable charge control agents. For example, metal complexes of organic compounds having a carboxyl group or a nitrogen-containing group, metal-containing dyes, nigrosine and the like can be mentioned. More specifically, Spiron Black TRH (Hodogaya Chemical Co., Ltd.), T-77 (Hodogaya Chemical Co., Ltd.), Bontron S-34 (Orient Chemical Co., Ltd.) Bontron E
-84 (manufactured by Orient Chemical Co.), Bontron N-01
(Orient Chemical Co., Ltd.) and Copy Blue-PR (Hoechst Co.) can be used. The charge control agent is based on 100 parts by weight of the polymerizable monomer.
It is preferable to use 0.01 to 10 parts by weight (more preferably 0.03 to 5 parts by weight).

In the production method of the present invention, after vacuum drying,
External addition processing is performed as necessary. In this external addition treatment, an additive (hereinafter, sometimes referred to as an external additive) is attached to and embedded in the surface of the colorant-containing polymer particles, thereby adjusting the particle charging characteristics, the fluidity of the particles, and the like. Can be.

Examples of the external additive include inorganic particles such as silica particles and titanium oxide particles; polystyrene particles, polymethyl methacrylate particles, styrene-methacrylate copolymer particles, a core composed of polystyrene and a shell composed of polymethyl methacrylate. Organic resin particles such as core-shell particles in which the core is composed of polymethyl methacrylate and the shell is composed of polystyrene. Of these,
Particularly preferred are hydrophobically treated silica particles. In addition, it is preferable to use a combination of the hydrophobic silica particles and the organic resin particles because the charging characteristics are improved. To attach an external additive to the polymer particles,
Usually, the external additive and the polymer particles are charged into a mixer such as a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and stirred.

The toner obtained by the production method of the present invention has a volume average particle size of usually 0.5 to 20 μm, preferably 1 to 20 μm.
10 μm, more preferably 2 to 8 μm. As the particle size increases, the resolution decreases.

[0049]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to only these examples. Parts and percentages are by weight unless otherwise specified.

In this example, evaluation was made by the following method. (Amount of residual monomer and volatile compound) Mass spectrometer JMS-DX303 (HF) (manufactured by JEOL)
Was measured under the following conditions. Column: HP-5 Column temperature: 50 ° C. to 300 ° C. (heating at 10 ° C./min) Injection temperature: 280 ° C. Sample preparation: 0.2 g of toner is placed in a 20 ml closed container and heated at 150 ° C. for 10 minutes. The gas generated by this is used as a measurement sample.

(Water content) Automatic moisture meter KF-05
The measurement was carried out under the following conditions using a moisture measuring device in which a moisture vaporizer VA-05 (manufactured by Mitsubishi Kasei Kogyo) was used in combination with (Mitsubishi Kasei Kogyo). Toner sample amount: 1 gram Water vaporization temperature: 180 ° C Carrier gas: Nitrogen gas

(Evaluation of image quality) Commercial printer (four-sheet machine)
And continuous printing with a densitometer of 1.3 or more with a reflection densitometer (manufactured by Macbeth) and a fog of non-image area of 10% or less with a whiteness meter (manufactured by Nippon Denshoku). (○) A toner that can continue 5,000 sheets or more was evaluated as (△), and a toner that could not continue 5,000 sheets or more was evaluated as (X).

(Evaluation of Odor) In the image quality evaluation described above,
The odor near the exit of the printing paper was sensory tested by five persons. Five people did not feel unpleasant odor (O), two or less people felt unpleasant odor (△), and three or more people felt unpleasant odor (X).

Example-1 83 parts of styrene 17 parts of butyl acrylate 17 parts of carbon black 7 parts of Monarch 120 (manufactured by Cabot) Charge control agent 1 part (Spiron Black TRH, manufactured by Hodogaya Chemical Co.) 3 parts of anti-offset agent (VISCOL 550P) Divinylbenzene 0.3 part t-butyl peroxy-2-ethylhexanoate 4 parts After stirring and mixing the above components with a usual stirring device, a Dyno mill (Synth) as a media type dispersing machine is used. The polymerizable monomer composition which was uniformly dispersed was prepared using the method of Maru Enterprises Co., Ltd.).

An aqueous solution prepared by dissolving 9 parts of magnesium chloride (a water-soluble polyvalent metal salt) in 250 parts of ion-exchanged water and an aqueous solution obtained by dissolving 5.5 parts of sodium hydroxide (alkali metal hydroxide) in 50 parts of ion-exchanged water Was added gradually under stirring to prepare a dispersion of a magnesium hydroxide colloid (a poorly water-soluble metal hydroxide salt colloid).

Next, the polymerizable monomer composition was charged into the dispersion obtained by the above reaction, and the polymerizable monomer composition was added using an Ebara Milder (manufactured by Ebara Corporation) which is a continuous emulsifying and dispersing machine. Droplets (monomer composition particles) of the composition were granulated.
The aqueous dispersion of the granulated polymerizable monomer composition is placed in a reactor equipped with a stirring blade and stirred at 90 ° C. for 10 hours to carry out a polymerization reaction, and an aqueous dispersion of the polymer (toner particles) is obtained. Obtained.

While the aqueous dispersion of the polymer obtained above was stirred, the pH of the system was adjusted to 6 or less with sulfuric acid, and acid washing (2
5 ° C for 10 minutes), and after separating water by filtration,
Add 500 parts of ion-exchanged water to reslurry,
Water washing was performed. Thereafter, filtration, dehydration, and water washing were repeated several times, and the solid content was separated by filtration to obtain wetted colorant-containing polymer particles having a volume average particle diameter of 7.5 μm. The colorant-containing polymer particles were placed in the container of the vacuum dryer shown in FIG.
Vacuum dried at 0 ° C. During the drying period, the polymer particles were stirred by rotating a stirring blade. The vapor was condensed and removed in a condenser. Nitrogen gas was injected into the container at a rate of 5 l / min (standard state). The inside of the container became 35 torr. The temperature of the polymer particles was about 30 ° C. and rose to about 33 ° C. just before the drying was completed. When the temperature reached 34 ° C., the drying was completed. The drying time was about 7 hours. Then, 0.5 part of silica fine particles obtained by hydrophobizing 100 parts of the dried polymer particles and 0.3 part of organic fine particles (particles having a core-shell structure of polystyrene core and polymethacrylate shell) are put into a Henschel mixer. After stirring, the silica particles and the organic fine particles were attached to the polymer particles to obtain a toner.

The amount of the residual monomer in the toner is 100 ppm
The decomposition product of the polymerization initiator was t-butyl alcohol 120 ppm, 1-heptene 20 ppm, the water content was 0.12%, the odor was evaluated as ○, and the image quality was evaluated as ○.

Example 2 A toner was obtained in the same manner as in Example 1 except that the nitrogen gas injection rate used in Example 1 was changed to 15 l / min (standard state). The inside of the container was 42 torr. The drying time was about 9 hours.

The amount of the residual monomer in the toner is 110 ppm
The decomposition product of the polymerization initiator, t-butyl alcohol 130 ppm, 1-heptene 28 ppm, water content 0.15%, odor evaluation was ○, and image quality evaluation was ○.

Example 3 A toner was obtained in the same manner as in Example 1 except that air was used instead of the nitrogen gas used in Example 1. 35 to inside the container
rr. The drying time was about 7 hours.

The amount of the residual monomer in the toner is 100 ppm
The decomposition product of the polymerization initiator, t-butyl alcohol 100 ppm, 1-heptene 22 ppm, water content 0.10%, odor evaluation was ○, and image quality evaluation was ○.

Comparative Example 1 A toner was obtained in the same manner as in Example 1 except that nitrogen gas was not injected. The drying time was about 12 hours.

The amount of the residual monomer in the toner was 530 ppm.
The decomposition product of the polymerization initiator, t-butyl alcohol 2100 ppm, 1-heptene 700 ppm, water content 0.25%, odor evaluation x, image quality evaluation ○.

[0065]

According to the production method of the present invention, polymer particles can be dried in a short time. Further, the toner obtained by this method has very low residual monomers, and thus has high environmental safety. Further, since drying can be performed without causing thermal aggregation or the like, image characteristics are good.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a vacuum dryer used in the production method of the present invention.

[Explanation of symbols]

 1. Jacket 2. Stirring blade 3. Condenser 4. Bag filter 5. Gas inlet 6. Thermometer

Claims (2)

[Claims] 1. A method for producing a toner, comprising a step of vacuum drying colorant-containing polymer particles while injecting a gas. 2. The method according to claim 1, wherein the temperature of the colorant-containing polymer particles is adjusted to 50 ° C. or lower.