JP2002148857A - Method of manufacturing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which toner having environmental safety is manufactured with a high yield in a short time because residual polymerized monomer and a volatile polymerization start agent dissolved product or the like are reduced. SOLUTION: The toner is made of vacuum-drying coloring polymerized particles in a state that particulates smaller than the coloring polymerized particles coexist under a condition where the maximum value of average ventilation speed per hour at a bug filter is set as 1-30 m/minute by using a vacuum drying machine in which the bug filter is fixed at an exhaust port by a clamping means such as a bolt and a sealing means such as a silicone seal agent.

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 producing a toner excellent in environmental safety in a short time with little residual polymerizable monomers and volatile polymerization initiator decomposition products. The present invention relates to a method for producing a high yield.

[0002]

2. Description of the Related Art In general, a toner for electrophotography is a pulverization comprising colored polymer particles obtained by kneading, pulverizing and classifying a binder resin obtained by polymerization with a coloring agent, a charge controlling agent, a release agent and the like. And a color toner obtained by polymerizing a mixture of a polymerizable monomer, a colorant, a charge controlling agent, a release agent, and the like by a method such as suspension polymerization, emulsion polymerization, or dispersion polymerization. Toner: particles obtained by stirring and associating particles of a binder resin with particles containing a colorant and a charge control agent at a temperature higher than the glass transition temperature of the binder resin, and filtering and drying the resulting particles. An association method toner comprising the obtained colored polymer particles; and the like. In any method, it is difficult to completely react the polymerizable monomer in the polymerization step, and a small amount of unreacted polymerizable monomer remains in the toner. When the toner having the polymerizable monomer remaining therein is used in an electrostatic image forming apparatus, the residual polymerizable monomer is volatilized from the toner due to heating during image fixing or the like, or the working environment is deteriorated.
This produces an unpleasant odor. Further, electrophotographic toners having a large amount of residual polymerizable monomers have problems such as easy blocking during storage, easy offset during image fixing, and easy filming on members of an electrostatic image developing device. .

[0003] In order to reduce volatile substances such as residual polymerizable monomers in colored polymer particles, removal of volatile substances in each step after the polymerization reaction is often studied.
For example, a method of performing steam stripping treatment when a polymer is in a state of a suspension, an emulsion, or the like is known.
However, in steam stripping, the colored polymer particles undergo thermal aggregation due to heating, and the particle size distribution is widened.
Furthermore, the block may be formed as the thermal aggregation proceeds. Further, by heating and drying the colored polymer particles, unreacted polymerizable monomers and volatile compounds are removed together with water. For drying, a spray dryer, a fluidized bed dryer, a tray dryer or a vacuum dryer is used. In these drying methods, it takes a long time to reduce the volatile components, and when the volatile components evaporate, agglomeration or the like occurs, and the particle size distribution is sometimes widened. Furthermore, the colored polymer particles are discharged out of the system together with the exhaustion of the volatile components, so that the yield often decreases.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to produce a toner which is low in residual polymerizable monomers and decomposition products of volatile polymerization initiators and is excellent in environmental safety in a short time and with a high yield. It is to provide a method. The present inventors have conducted intensive research to achieve the above object, and as a result, exhausted gas was passed through a bag filter fixed by a specific method at a high speed, and the colored polymer particles were vacuum-dried. The present inventors have found out what can be achieved, and have completed the present invention based on this finding.

[0005]

Thus, according to the present invention, the average air flow rate per hour in a bag filter is determined by using a vacuum dryer in which the bag filter is fixed to an exhaust port by a fastening means and a seaming means. Maximum value is 1-3
A method for producing a toner is provided, which comprises vacuum-drying colored polymer particles under a condition of 0 m / min.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a toner according to the present invention uses a vacuum dryer in which a bag filter is fixed to an exhaust port of a vacuum dryer by fastening means and seaming means.
The method includes vacuum-drying the colored polymer particles under the condition that the maximum value of the one-hour average ventilation speed in the bag filter is 1 to 30 m / min.

The vacuum dryer used in the present invention comprises:
It has a bag filter. A bag filter is generally used to remove dust from dust-containing gas, and is classified into a mechanical vibration type, a back pressure type, a pulse jet type, and the like according to a form of removing accumulated dust. The bag filter is formed from a bag-shaped filter cloth, and has a shape such as an envelope shape or a cylindrical shape. In addition, there are a type in which a plurality of filter cloths are attached and the device is divided into a multi-chamber structure to pay off each room, and a type in which the device is partially removed without dividing the device. In the present invention, any type may be used, but an inert gas is blown into the downstream portion of the bag filter when the pressure difference between the upstream portion and the downstream portion of the bag filter exceeds 1.5 kPa, In particular, the pulse jet type is preferable because the drying time can be shortened and the toner can be manufactured with a high yield. Examples of the inert gas include nitrogen, helium, and carbon dioxide.

FIG. 1 is a diagram showing an example of a bag filter that can be used in the present invention. The exhaust gas accompanied by the colored polymer particles enters from the lower part, passes through a cylindrical filter cloth (bag filter) 2, and is discharged to the upper part. The pressure difference between the upstream portion and the downstream portion of the bag filter is measured by the pressure difference meter 3, and when the pressure difference exceeds 1.5 kPa, an inert gas such as nitrogen is discharged from the pulse jet outlet 4 to the downstream side of the bag filter. It blows into the section, and can remove particles deposited on the bag filter.

The bag filter is attached to an exhaust port of a vacuum dryer. Attachment of the bag filter is fixed by fastening means and seaming means. Tightening means means means for fixing the bag filter and the exhaust port by tightening them, and specifically includes means such as bolting and banding. The seaming means is a means for filling the gap between the bag filter and the exhaust port to eliminate leakage,
Specifically, there are means such as a sealing material, a packing material, and an adhesive. Silicone sealants (for example, Cemedine 8060, Three Bond 52
11, Three Bond 5222, etc.), a synthetic rubber adhesive (for example, Three Bond 1521C), an instantaneous strong adhesive (for example, Three Bond 1700 series), and the like. Examples of the packing material include an asbestos packing material, a felt packing material, and a rubber packing material. FIG. 2 is an enlarged view of a mounting portion of the bag filter of FIG. A packing material 12 is attached to the end 14 of the cylindrical filter cloth 2, and a silicone sealing material is applied to the packing material 12. The packing material is sandwiched between the gauge plate 16 and the holding plate 15 and is fixedly fastened with bolts 17 and nuts.

As the vacuum dryer used in the present invention, a material stationary vacuum drying apparatus such as a box type (shelf step type) or a manifold type; a mechanical transport type vacuum type such as a tunnel type, a belt type, a roll type, a drum type, etc. Equipment; cylindrical (groove) stirring type,
A mechanical stirring type vacuum device such as a cylindrical rotary type and a special rotary type may be used. Of these, a cylindrical (groove) stirring type vacuum drying apparatus is preferably used. In the dryer, the colored polymer particles may be vacuum-dried while standing, but preferably stirred to promote evaporation or sublimation of volatile components. More specifically, as a vacuum dryer, commercially available SV mixer manufactured by Shinko Pantech Co., Ltd., particularly a T series such as SV-001VT, a conical ribbon mixing dryer manufactured by Okawara Seisakusho, or a conical blender dryer manufactured by Nippon Dryer Co., Ltd. No. FIG. 3 is a diagram illustrating an example of a vacuum dryer usable in the present invention. In the apparatus of FIG. 3, a screw blade 22 is used as a stirring blade. The inside of the dryer is heated and reduced in pressure, and the colored polymer particles are dried while being stirred by the stirrer. The evaporated volatile components are guided to the exhaust port, pass through the bag filter 24, and are liquefied and separated in the condenser 23. A compressor (not shown) is provided downstream of the condenser, and the pressure inside the dryer is adjusted according to the operating conditions of the compressor. The ventilation speed in the bag filter can be adjusted by any one of the jacket temperature, the cooling water temperature of the condenser, and the pressure in the dryer, or a combination thereof, and is mainly adjusted by the jacket temperature.

The colored polymer particles used in the present invention are particulate polymers containing a colorant. Colorants include carbon black, titanium white, nigrosine base,
Aniline blue, calco oil blue, chrome yellow, ultramarine blue, orient oil red,
Dyes and pigments such as phthalocyanine blue and malachite green oxalate; magnetic particles such as cobalt, nickel, iron sesquioxide, triiron tetroxide, iron manganese oxide, iron zinc oxide and nickel iron oxide; further,
Colorants for magnetic color toners include C.I. I. Direct Red 1 and 4, C.I. I. Acid Red 1, C.I.
I. Basic Red 1, C.I. I. Modern Red 3
0, 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, neftol yellow S,
Hanzayero G, Permanent Yellow NCG, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4
R, 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.

The magenta coloring pigment for full-color toner includes 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. And basic dyes such as Basic Violet 1 to 28. Examples of cyan color pigments for full-color toner 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. Further, yellow coloring pigments for full-color toners include C.I. I. Pigment Yellow 1-138,
C. I. Bat yellow 1 to 20 and the like. These coloring agents are used in a proportion of usually 0.1 to 100 parts by weight, preferably 1 to 50 parts by weight, based on 100 parts by weight of the polymer constituting the colored polymer particles.

The colored polymer particles may be produced, for example, by (1) a method in which a resin, a colorant, and other additives are melt-kneaded, pulverized, and classified if necessary;
A method of polymerizing a monomer in which a colorant and other additives are dispersed, washing and drying; (3) polymerizing a mixture containing the monomers to obtain fine particles, mixing the fine particles with other additives and aggregating the fine particles Washing, drying and the like.
Among them, the method (2) is preferable because it does not require labor such as classification and can obtain spherical particles.

As the resin constituting the colored polymer particles, a styrene- (meth) acrylate copolymer or a polyester resin is usually used. Examples of the method of polymerizing a polymerizable monomer in which a colorant and other additives are dispersed include an emulsion polymerization method, a suspension polymerization method, a precipitation polymerization method, a dispersion polymerization method, and the like. The suspension polymerization method which can easily obtain a suitable particle size as the colored polymer particles of the above is preferable. In the polymerization method, the polymerization of the polymerizable monomer for obtaining the resin constituting the colored polymer particles may be performed in one step, or may be performed in two steps. 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 storage stability 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 crosslinkable monomer include 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. When the number average molecular weight is smaller than 1,000, the surface portion of the colored polymer particles becomes soft, and the storage stability decreases. Conversely, the number average molecular weight is 30,00
If the ratio is larger than 0, the meltability of the macromonomer is deteriorated and the fixability is lowered. 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 styrene, a styrene derivative, a methacrylate, an acrylate, acrylonitrile, a polymer obtained by polymerizing two or more kinds of methacrylonitrile alone, and a polysiloxane skeleton. A macromonomer having the following structure, from pages 4 to 7 of JP-A-3-203746.
And the like disclosed on the page. The amount of the macromonomer is usually 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the monovinyl monomer.
03 to 5 parts by weight, more preferably 0.05 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 a polymerization auxiliary material such as a polymerization initiator and a molecular weight regulator for polymerizing a monomer, those used in a usual polymerization method can be used. As the polymerization initiator used in the present invention, it is preferable to use one that is soluble in the monomer used. More specifically, methyl ethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxod, t-butyl peroxy-2ethyl hexaniate, Peroxides such as -iso-propylperoxydicarbonate and di-t-butyldiperoxyisophthalate; 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisiso Azo compounds such as butyronitrile and 1,1′-azobis (1-cyclohexanecarbonitrile); The polymerization initiator is usually 0.1 to 20 parts by weight, based on 100 parts by weight of the monovinyl monomer,
It is particularly preferable to use 1 to 10 parts by weight.

Examples of the molecular weight modifier used as required in the present invention include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan; halogenation such as carbon tetrachloride and carbon tetrabromide. Examples of hydrocarbons include α-methylstyrene dimer and the like. 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 usually 0.01 to 10 parts by weight, especially 0.1 to 100 parts by weight of the monovinyl monomer.
It is preferable to use up to 5 parts by weight.

In the polymerization for obtaining the colored polymer particles used in the present invention, a dispersion stabilizer is used to stably disperse (suspend) the monomers in an aqueous medium. Examples of the dispersion stabilizer include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide; and aluminum hydroxide. , Magnesium hydroxide, metal hydroxides such as ferric hydroxide; polyvinyl alcohol, methyl cellulose,
Water-soluble polymers such as gelatin; anionic surfactants, nonionic surfactants, amphoteric surfactants, and the like. Among these, dispersion stabilizers containing metal compounds, especially colloids of poorly water-soluble metal hydroxides, are preferred because they can narrow the particle size distribution of polymer particles and improve the sharpness of images. is there. The dispersion stabilizer containing a colloid of a poorly water-soluble metal hydroxide is not limited by its manufacturing method, but the poorly water-soluble metal obtained by adjusting the pH of an aqueous solution of a water-soluble polyvalent metal compound to 7 or more is used. It is preferable to use a colloid of a hydroxide, particularly a colloid of a poorly water-soluble metal hydroxide generated by a reaction of a water-soluble polyvalent metal compound with an alkali metal hydroxide in an aqueous phase. The colloid of the poorly water-soluble metal compound used in the present invention has a number particle size distribution D
Preferably, 50 (50% cumulative value of the number particle size distribution) is 0.5 μm or less, and D90 (90% cumulative value of the number particle size distribution) is 1 μm or less. When the particle size of the colloid is large, the stability of polymerization is lost, and the yield of the toner is reduced. The dispersion stabilizer is used in an amount of usually 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer. If this ratio is small, it is difficult to obtain sufficient polymerization stability and dispersion stability, and aggregates are easily formed. If this ratio is large, the particle size distribution tends to be widened due to the increase in fine particles.

The colored polymer particles used in the present invention may contain a release agent (wax), a charge controlling 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 polyethylene, low-molecular-weight polypropylene, low-molecular-weight polyolefins such as low-molecular-weight polybutylene, waxes; polyhydric alcohols such as pentaerythritol and dipentaerythritol, and stearin Ester compounds comprising an aliphatic monocarboxylic acid such as an acid (specifically, pentaerythritol tetramyristate, pentaerythritol tetralaurate,
Dipentaerythritol hexamyristate, glycerol triaraquinic acid, etc.). The release agent is preferably used in an amount of usually 0.1 to 20 parts by weight, particularly preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymer constituting the colored polymer particles.

Examples of the charge controlling agent include Bontron N01 (manufactured by Orient Chemical Co., Ltd.) and Nigrosine base EX.
(Orient Chemical Co., Ltd.), Spiro Black TRH (Hodogaya Chemical Co., Ltd.), T-77 (Hodogaya Chemical Co., Ltd.), Bontron S-34 (Orient Chemical Co., Ltd.), Bontron E
-81 (manufactured by Orient Chemical Co.), Bontron E-84
(Orient Chemical), Bontron E-89 (Orient Chemical), Bontron F-21 (Orient Chemical), COPY CHRGE NX (Clariant), COPY CHRGE NEG (Clariant), TNS-4 -1 (Hodogaya Chemical Co., Ltd.), TNS-
4-2 (manufactured by Hodogaya Chemical Co., Ltd.), LR-147 (manufactured by Nippon Carlit); quaternary ammoniums described in JP-A-11-15192, JP-A-3-175456, JP-A-3-243954 and the like. (Salt) group-containing copolymer, JP-A-3-243954, JP-A-1-217
And sulfonic acid (salt) group-containing copolymers described in JP-A No. 464, JP-A-3-15858 and the like. Of these, a quaternary ammonium (salt) group-containing copolymer or a sulfonic acid (salt) group-containing copolymer is preferred. The charge controlling agent is usually 0.01 to 10 parts by weight, based on 100 parts by weight of the polymer constituting the colored polymer particles,
Preferably, it is used in a ratio of 0.1 to 7 parts by weight.

In the production method of the present invention, the maximum value of the average ventilation speed per hour is 1 to 30 m / min, preferably 4 to 30 m / min.
The gas is allowed to pass through the bag filter under the condition of 25 m / min. By setting it in this range, the drying time can be greatly reduced. Here, the ventilation speed is a value obtained by dividing the exhaust amount (the exhaust volume per minute [m ³ / min] under the operation condition of the vacuum dryer) by the filter cloth area [m ² ].
The aeration rate usually varies with the course of the drying process.
In the present invention, the average value of the ventilation rate every hour from the start of drying is determined, and the maximum value is set in the above range.

The pressure in vacuum drying is usually 1240
The pressure is 0 Pa or less, preferably 9600 Pa or less, and more preferably 7500 Pa or less. When the pressure is high, the evaporation of volatiles decreases, and the drying efficiency decreases. In addition, when the pressure is high, the temperature inside the dryer increases, and thermal deterioration is likely to occur. Jacket temperature in vacuum drying is usually 15 to
80 ° C, preferably 20-60 ° C, more preferably 2
5-50 ° C. When the jacket temperature is high, thermal aggregation of the colored polymer particles tends to occur. Conversely, if it is low, the drying speed will be low, and it will take time to dry. 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 colored polymer particles themselves during vacuum drying may be important. That is, in the present invention, the temperature of the colored polymer particles themselves,
It is preferably at most 50 ° C, more preferably at most 35 ° C. When the temperature of the colored polymer particles themselves increases, the colored polymer particles tend to agglomerate and fuse together.

In the production method of the present invention, preferably,
Fine particles having a particle size smaller than the colored polymer particles are added to the colored polymer particles, and dried under vacuum. The timing of adding the fine particles is not particularly limited as long as the fine particles coexist with the colored polymer particles during vacuum drying, but the water content is 60% or less, preferably 10 to 60%, more preferably 15 to 50%. ,
It is particularly preferable to add fine particles to the colored polymer particles in a wet state of 20 to 45%, and to dry while mixing. For example, the colored polymer particles produced by the polymerization method or the aggregation method are washed, and the colored polymer particles in a wet state after filtration are added with fine particles, and dried while mixing the colored polymer particles and the fine particles. .

As the fine particles, various organic fine particles and / or inorganic fine particles can be used. As fine particles,
It is preferable to use hard fine particles having an average particle size smaller than the volume average particle size (dv) of the colored polymer particles because the colored polymer particles and the solid fine particles are easily separated by classification after the drying step. The average particle size of the fine particles is preferably 1 μm or less, more preferably 0.5 μm or less. Examples of the organic fine particles include styrene-based polymer fine particles polymerized and / or granulated by a wet polymerization method such as an emulsion polymerization method, a soap-free emulsion polymerization method, a non-aqueous dispersion polymerization method, a gas phase method, and the like, and a (meth) acrylate polymer. Coalesced fine particles, olefin-based polymer fine particles, fluorine-containing polymer fine particles, nitrogen-containing (meth) acrylate-based polymer fine particles, silicone-based polymer fine particles,
Various organic fine particles such as benzoguanamine-based resin fine particles, melamine-based resin fine particles, carbon black, and graphite are exemplified.

Examples of the inorganic fine particles include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, and diamond carbon random. Carbide; various nitrides such as boron nitride, titanium nitride and zirconium nitride; borides such as zirconium boride; iron oxide;
Various oxides such as chromium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, titanium oxide, tin oxide, alumina and silica; sulfides such as molybdenum disulfide; fluorides such as carbon fluoride; aluminum stearate; Various metal soaps such as calcium stearate, zinc stearate, and magnesium stearate; various non-magnetic inorganic fine particles such as talc and bentonite; It is preferable that the surfaces of these organic fine particles and inorganic fine particles are surface-treated with a silane coupling agent, a titanium coupling agent, silicone oil, or modified silicone oil.
Among these, surface-treated silica fine particles such as hydrophobic silica fine particles are particularly preferable.

The fine particles are generally used in an amount of 0.01 to 100 parts by weight (based on solid content) of the wet colored polymer particles.
1 part by weight, preferably 0.02 to 0.5 part by weight, more preferably 0.03 to 0.2 part by weight. If the addition amount of the fine particles is too small, the effect of preventing the aggregation of the colored polymer particles in the drying step is small, and the effect of improving the fluidity of the colored polymer particles after drying is also small. If the added amount of the solid fine particles is too large, excessive flow of the toner occurs in the classification step after drying, and the line tends to leak in the production step. The fine particles can be added to the colored polymer particles and then dried, or the fine particles can be added and dried while drying the colored polymer particles.

In the production method of the present invention, after vacuum drying,
External addition processing is performed as necessary. In the external addition treatment, the particle charging characteristics, the fluidity of the particles, and the like can be adjusted by attaching and embedding an additive (hereinafter, sometimes referred to as an external additive) on the surface of the colored polymer particles. . 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, or a core composed of polymethyl methacrylate. Organic resin particles such as core-shell particles composed of methyl methacrylate and having a shell made of polystyrene. Among them, particularly preferred are silica particles subjected to hydrophobic treatment. 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. In order for the external additive to adhere to the colored polymer particles, the external additive and the colored polymer particles are usually 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 tends to decrease.

[0031]

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 the present example, evaluation was made by the following method. (Particle size and particle size distribution) Volume average particle size of polymer particles (d
v) and the particle size distribution (volume average particle size / number average particle size)
The measurement was performed using a multisizer (Beckman Coulter, manufactured by Coulter, Inc.). Multisizer measurement
The measurement was performed under the conditions of an aperture diameter of 100 μm, a medium of Isoton II, a concentration of 10%, and the number of measured particles = 100,000. (Thickness of Shell) The thickness of the shell of the polymerized toner having the core-shell structure can be measured with a multisizer or an electron microscope if the thickness is large. Is calculated using x = r (1 + s / 100ρ) 1/3 -r (1) where, r: radius of average particle diameter of core polymer particles before addition of shell monomer (volume particle diameter of multisizer: μm) x : Shell thickness (μm) s: Number of parts of shell monomer added (parts per 100 parts of core monomer) ρ: Density of shell polymer (g / cm 3);
Calculated as 0. (Sphericity) The sphericity of the polymerized toner is calculated by calculating the area (Sc) of a circle having the absolute maximum length of the particle as the diameter and the actual projected area (Sc) of the particle.
r), and 100 values were measured from the reflection electron micrograph of the polymerized toner, and the average value was calculated.

(Fixing Temperature) The fixing temperature of the polymerized toner is controlled by a commercially available non-magnetic one-component developing type printer (printing speed = 1).
(6 sheets / min) was evaluated by performing a fixing test using a printer modified so that the temperature of the fixing roll portion could be changed. The fixing test was performed by changing the temperature of the fixing roll of the modified printer, measuring the fixing rate of the developer at each temperature, and determining the relationship between the temperature and the fixing rate. The fixation rate is calculated from the ratio of the image density before and after the tape peeling operation of the solid black area on the test paper printed by the remodeled printer, after the temperature is changed, to stabilize the temperature of the fixing roll for at least 5 minutes, and then print with a modified printer. Calculated. That is, assuming that the image density before tape removal is before ID and the image density after tape removal is after ID, the fixing rate can be calculated from the following equation. Fixing rate (%) = (after ID / before ID) × 100 Here, the tape peeling operation is to attach an adhesive tape (Scotch Mending Tape 810-3-18 manufactured by Sumitomo 3M Limited) to the measurement portion of the test paper, This is a series of operations in which the adhesive tape is pressed and adhered at a constant pressure, and then the adhesive tape is peeled in a direction along the paper at a constant speed. The image density was measured using a Macbeth reflection image densitometer. In this fixing test, the fixing roll temperature corresponding to a fixing rate of 80% was defined as the fixing temperature (° C.) of the developer.

(Preservation) The preservation of the polymerized toner was evaluated as follows.
Put the polymerized toner sample in a sealed container, and after sealing,
It was immersed in a thermostatic water bath whose temperature was controlled at 55 ° C., taken out after a certain period of time, and measured by measuring the weight of the aggregated toner. 4 samples removed from the container
Carefully transfer the structure onto a 2-mesh sieve so as not to destroy the structure as much as possible, and store the vibration intensity memory of a powder measuring machine (trade name: Powder Tester, manufactured by Hosokawa Micron Corporation) at 4.5.
After shaking for 30 seconds, the weight of the toner remaining on the sieve was measured, and the result was defined as the weight of the aggregated toner. The aggregation rate (% by weight) of the toner was calculated from the weight of the aggregated toner and the weight of the sample.

(Print durability test) Temperature 23 ° C., relative humidity 5
Under a 0% condition, using a commercially available non-magnetic one-component developing system printer (printing speed = 16 sheets / min), put the polymerized toner to be evaluated in the developing device of the printer, perform continuous printing from the beginning, and perform reflection. Continuous printing with a print density of 1.3 or higher using a densitometer (manufactured by Macbeth) and an image quality of 15% or less of fog on the photoreceptor in the non-image area measured by a whiteness meter (manufactured by Nippon Denshoku) I checked the number. Fog was examined by attaching an adhesive tape (Scotch Mending Tape 810-3-18 manufactured by Sumitomo 3M) to a non-image area on the photoreceptor. Specifically, an adhesive tape is attached to a non-image portion of the photoreceptor before printing, and then peeled off, and this is attached to white paper, and whiteness A is measured. On the other hand, an adhesive tape is adhered to the non-image portion of the photoreceptor after printing, and then peeled off. This is adhered to blank paper, and whiteness B is measured. Fog can be calculated by the following equation. The continuous printing was performed at a print density of 5%, and the print density and fog were checked every 500 sheets. Fog (%) = AB

(Endothermic peak temperature) ASTM-D-341
It was measured according to 8-82. The DSC curve was measured at a heating rate of 10 ° C./min, and the peak top was taken as an endothermic peak. The differential scanning calorimeter used was “SSC5200” manufactured by Seiko Instruments Inc. (Dissolution amount) The amount of dissolution of the low softening point substance in styrene is
The amount of the low softening point substance dissolved in 100 g of styrene maintained at 25 ° C. (g / 100 gST) was measured.

(Acid value) JIS-K-1557- 1970
It measured according to. Specifically, about 50 g of a sample is placed in 300
weigh correctly in a ml beaker and add acetone (80v
(V /%), and after dissolution, the solution was subjected to potentiometric titration with a 0.1N aqueous NaOH solution using a PH meter. The inflection point of the obtained titration curve is set as the end point. The acid value was determined from the following equation. A = [5.61 × (BC) × f] / S where A: acid value (mg KOH / g) B: amount of 0.1N sodium hydroxide aqueous solution (ml) required for titration of the sample C: Amount of 0.1N sodium hydroxide aqueous solution required for titration in blank test (ml) f: Factor of 0.1N sodium hydroxide aqueous solution S: Amount of sample (g)

(Water content) 1 g of the polymerized toner sample was
It was precisely weighed to mg (w1). Put the sample in a dryer at 105 ° C (temperature error at each site is 1 ° C or less) and dry for 1 hour.
After cooling, it was weighed again (w2). Using these measured values, the water content was calculated by the following equation. Water content (%) = [(w1-w2) / w1] × 100 (Drying time) Polymer particles are sampled from the start of drying, and the water content of the toner is measured each time. The time when the water content became 0.3% or less was defined as the drying time.

(Fluidity) The openings are 150 μm and 75, respectively.
Three types of sieves of μm and 45 μm are stacked in this order from the top, and 4 g of the polymerized toner to be measured is precisely weighed and placed on the uppermost sieve. Next, the three kinds of the sifted screens were vibrated for 15 seconds under the condition of the vibration strength scale 4 using a powder measuring device (trade name “Powder Tester” manufactured by Hosokawa Micron Co., Ltd.), and then remained on each screen. Measure the weight of the developer. Substituting each measurement into the following equations: and a, b, and c
Is calculated, and then these values are put into an equation to calculate the value of the fluidity. The measurement was performed three times per sample, and the average value was determined. a = [(weight of polymer remaining on 150 μm sieve (g)) / 4
g] × 100 b = [(weight of polymer remaining on 75 μm sieve (g)) / 4
g] × 100 × 0.6 c = [(weight of polymer remaining on 45 μm sieve (g)) / 4
g] × 100 × 0.2 Flowability (%) = 100− (a + b + c)

(Amount of Residual Monomer and Volatile Compound) Mass Spectrometer JMS-DX303 (HF)
(Manufactured by JEOL Ltd.) 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. (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 80.5 parts of styrene and 19.5 of n-butyl acrylate
Parts of the polymerizable monomer for core (calculated Tg of the obtained copolymer = 55 ° C.), 7 parts of carbon black (manufactured by Mitsubishi Chemical Corporation, trade name # 25), and a charge control agent (manufactured by Hodogaya Chemical Co., Ltd.) 1 part of trade name Spiron Black TRH, 0.3 part of divinylbenzene, and polymethacrylate macromonomer (Toa Gosei Chemical Industry Co., Ltd., AA6, Tg = 94)
After stirring and mixing 0.3 part with a usual stirring device, the mixture was uniformly dispersed by a media type disperser. Here, dipentaerythritol tetramyristate [endothermic peak temperature = 63 ° C., solubility in styrene 20 (g / 100 g ST: 25 ° C.), acid value 1 (mg KO)
H / g) or less], and mixed and dissolved to obtain a polymerizable monomer mixture for core (mixture liquid). 5.8 parts of sodium hydroxide (alkali metal hydroxide) was dissolved in 50 parts of ion-exchanged water in an aqueous solution in which 9.5 parts of magnesium chloride (water-soluble polyvalent metal salt) was dissolved in 250 parts of ion-exchanged water at room temperature. Magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid)
A dispersion was prepared. When the particle size distribution of the formed colloid was measured by a particle size distribution analyzer (SALD2000A type, manufactured by Shimadzu Corporation), the particle size was D50 (50% cumulative value of the number particle size distribution) of 0.36 μm. , D90 (90% cumulative value of the number particle size distribution) was 0.62 μm.

Methyl methacrylate (calculated Tg = 105
C) 3 parts and 100 parts of water were finely dispersed by an ultrasonic emulsifier to obtain an aqueous dispersion of a polymerizable monomer for shell. The particle size of the droplets of the polymerizable monomer for shell in the aqueous dispersion was measured with a particle size distribution analyzer (SALD2000A type, manufactured by Shimadzu Corporation).
m. The polymerizable monomer mixture for the core is added to the magnesium hydroxide colloid dispersion, and the mixture is stirred until the droplets are stabilized, and the polymerization initiator t-butyl peroxyisobutyrate (manufactured by NOF Corporation, product Name "Perbutyl I
B ") 5 parts were added, and using an Ebara milder, 15,
The mixture was stirred with high shear at a rotation speed of 000 rpm for 30 minutes to granulate droplets of the polymerizable monomer composition in the dispersion. The liquid dispersion of the granulated polymerizable monomer mixture was put into a reactor equipped with a stirring blade, the polymerization reaction was started at 95 ° C., and when the polymerization conversion reached almost 100%, sampling was performed. The volume average particle size of the colored polymer particles serving as the core was measured. As a result, the volume average particle size of the colored polymer particles was 6.4 μm
Met. Next, an aqueous dispersion of a polymerizable monomer for a shell and a water-soluble initiator [trade name “VA-08 manufactured by Wako Pure Chemical Industries, Ltd.”
6 "; 0.3 part of 2,2 'azobis [2-methyl-N- (2-hydroxyethyl) -propionamide]] was dissolved in 65 parts of distilled water and charged into the reactor. After the polymerization was continued for 3 hours, the reaction was stopped to obtain an aqueous dispersion of polymer particles having a pH of 9.5. The shell thickness calculated from the amount of the polymerizable monomer for shell and the core particle size was 0.03 μm, the sphericity (Sc / Sr) was 1.1, and the DSC measurement showed that
An endothermic peak of the low softening point substance appeared around 63 ° C.

While stirring the aqueous dispersion of the polymer particles having the core-shell structure obtained above, the system
H was adjusted to 4 or less to perform acid washing (25 ° C., 10 minutes), and water was separated by filtration. Next, 500 parts of ion-exchanged water was newly added to reslurry, and water washing was performed. Thereafter, dehydration and water washing were repeated several times, and the solid content was separated by filtration. Thus, wet polymer particles (wet cake) were obtained. After the wet cake was dried at 105 ° C. for 1 hour with a hot air drier, the water content was measured to be 38%. To 100 parts of the wet cake having a water content of 38%, 0.1 part of hydrophobic silica (trade name “R972”, manufactured by Nippon Aerosil Co., Ltd .; average particle diameter: 16 nm) was added as solid fine particles. Next, the wet cake to which the hydrophobized silica has been added is
It is placed in a vacuum dryer having the structure shown in FIG.
The drying was performed while rotating and stirring the stirring blade under a reduced pressure of 900 Pa. A bag filter is provided at an exhaust port of the vacuum drying device. This bag filter has a structure shown in FIG. 1, in which exhaust accompanied by colored polymer particles enters from below, passes through a cylindrical filter cloth (bag filter), and is discharged upward. The pressure difference between the upstream part and the downstream part of the bag filter is measured with a pressure difference meter, and when the pressure difference exceeds 1.5 kPa, nitrogen is blown into the bag filter downstream from the pulse jet outlet to the bag filter. The accumulated particles can be washed off. As shown in FIG. 2, a packing material is attached to an end of a cylindrical filter cloth, and a silicone sealing material is applied to the packing material. The packing material is sandwiched between the gauge plate and the holding plate, and is fixedly fastened with bolts and nuts.

Downstream of the bag filter, a condenser is provided, in which volatile components are liquefied and separated and removed. A compressor is provided downstream of the condenser, and the internal pressure of the dryer is adjusted according to the operating conditions of the compressor. The jacket temperature was adjusted such that the maximum value of the average ventilation speed per hour in the bag filter was 11 m / min. The temperature of the colored polymer particles themselves was about 30 ° C. and rose to about 33 ° C. just before the drying was completed. During drying,
In order to confirm the drying state several times, the polymer particles were sampled, the water content was measured, and the drying was stopped when the water content became 0.3% or less. Next, the dried polymer particles were classified to obtain dried particles. The measured flowability of the dried particles was 55%.

100 parts of the dried polymer particles having a core / shell structure were treated with hydrophobically treated colloidal silica (trade name “RX-200”, manufactured by Nippon Aerosil Co., Ltd .; average particle size: 1).
2 nm) and mixed using a Henschel mixer to prepare a toner. When the fixing temperature was measured using the toner obtained above, it was 130 ° C.
The storage stability of this toner was as good as 4%. Further, as a result of evaluating the image of the toner, an image having a high image density and an extremely good resolution without fog or unevenness was obtained. The number of durable printed sheets having fog of 15% or more was 23,000 sheets. The amount of residual monomer is 4
0 ppm, t-butyl alcohol, which is a decomposition product of the polymerization initiator, is 80 ppm, and 1-heptene is 2 pp.
The evaluation of m and odor was ○. The toner was manufactured continuously 20 times by the same operation as the above. The average value of the drying time in these 20 productions was 11 hours, and the average yield was 9
9% or more.

Example 2 A toner was obtained in the same manner as in Example 1 except that the maximum value of the average ventilation speed was adjusted to be 24 m / min. The average drying time in the 20 runs was 7 hours and the average yield was 9
9% or more.

Comparative Example 1 A toner was obtained in the same manner as in Example 1 except that the maximum value of the average ventilation speed was adjusted to 32 m / min. The average value of the drying time in the 20 productions was 16 hours, and the average yield was 95%. After manufacturing 20 times, when the bag filter and the condenser were opened, it was confirmed that toner leaked. Comparative Example 2 The packing material at the end of the cylindrical filter cloth was removed, and the end of the filter cloth was changed to a bag filter which was sandwiched between a gauge plate and a holding plate and fastened and fixed with bolts and nuts. A toner was obtained in the same manner as in Example 1, except that the value was adjusted to 2 m / min. The average drying time in the 20 runs was 24 hours and the average yield was 92.
%Met. After manufacturing 20 times, when the bag filter and the condenser were opened, it was confirmed that toner leaked.
In particular, leakage at the fixed portion of the filter cloth was remarkable.

[0047]

According to the production method of the present invention, the colored polymer particles can be dried in a short time and at a high yield. 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 diagram showing an example of a bag filter.

FIG. 2 is an enlarged view of a filter cloth attaching portion.

FIG. 3 is a diagram showing an example of a vacuum dryer used in the production method of the present invention.

[Explanation of symbols]

 2: filter cloth 3: pressure difference meter 4: pulse jet outlet 12: packing material 22: screw blade 23: condenser 24: bag filter

Claims (4)

[Claims] 1. Using a vacuum dryer in which a bag filter is fixed to an exhaust port by a fastening means and a seaming means, under a condition that the maximum value of the average ventilation speed per hour in the bag filter is 1 to 30 m / min. A method for producing a toner, comprising vacuum-drying colored polymer particles. 2. The method for producing a toner according to claim 1, wherein the temperature of the colored polymer particles is set to 50 ° C. or less. 3. The method for producing a toner according to claim 1, further comprising adding fine particles having a particle size smaller than that of the colored polymer particles and drying the resulting particles under vacuum. 4. The method according to claim 1, further comprising blowing an inert gas into a downstream portion of the bag filter when a pressure difference between an upstream portion and a downstream portion of the bag filter exceeds 1.5 kPa.