JP2003215840A - Method for manufacturing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a toner which can form a sharp image by electrophotography and in particular, to provide a method for manufacturing a toner having excellent spectral characteristics such as transparency necessary for reproduction of sharp tone of a color image when the method is adopted for a color toner. <P>SOLUTION: An electrification controlling resin composition prepared by mixing an electrification controlling resin and a coloring agent is dissolved and/or dispersed in a dispersion liquid comprising polymerizable monomers by using a mixer which generates an axial current. <P>COPYRIGHT: (C)2003,JPO

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 for electrophotography having a clear color tone regardless of the one-component system or the two-component system.

[0002]

2. Description of the Related Art In the electrophotographic method, an electrostatic latent image is formed on a latent electrostatic image bearing member made of a photoconductive photosensitive member by charging and exposure, and then the electrostatic latent image is formed by a toner containing a colorant. In this method, the image is developed, and the obtained toner image is transferred and fixed on a support such as transfer paper to obtain a visible image. As a toner for developing an electrostatic latent image, conventionally, a pulverized toner in which a colorant (carbon black, dye, pigment, etc.) is dispersed in a binder resin such as polystyrene and pulverized to a particle size of about 1 to 10 μm is used as the toner. Another example is a polymerized toner obtained by dispersing and dissolving a colorant in a polymerizable monomer, emulsifying or suspending it in an aqueous dispersion, polymerizing it, and then associating it if necessary.

In the electrophotographic method, colorization has recently progressed, and a color toner corresponding to a color image forming apparatus is required. The color image forming apparatus includes a plurality of image forming units, each of which forms a toner image of a different color, and yellow, magenta, cyan, and black color toner images are sequentially superposed on the same recording medium. It is known to transfer and perform color printing. Whether a crushed toner or a polymerized toner is used, the color toner is required to have the following characteristics.

(1) The toner has high transparency in order to superpose multiple colors. (2) Spectral reflection characteristics are excellent in order to reproduce colors. (3) To precisely control the positive or negative charging of the toner. (4) Low temperature fixing is possible. (5) Easy manufacture of color toner.

Various studies have been conducted to meet these demands. For example, in JP-A-61-149969, an additive for enhancing charging such as a homopolymer of an amine-containing monomer and a pigment are prepared by mixing them in a halogenated hydrocarbon such as chloroform by a roll mill. A toner composition is disclosed in which a pigment treated with an additive for enhancing charging is melt-mixed with resin particles and then pulverized. Japanese Patent Laid-Open No. 62-1195
No. 49, a binder resin is dissolved in a solvent, a colorant and a charge control agent are added to the solution, the mixture is stirred and mixed, the solvent is removed by a freeze-drying method, and then the obtained toner is pulverized and classified. A method of making a toner is disclosed. Japanese Patent Laid-Open No. 03-1
In JP 55568, a binder resin, at least one of a dye and a pigment, and an organic solvent are mixed and kneaded to produce a master batch of a dye or a pigment. A method for producing a toner by mixing, kneading, pulverizing and classifying with other additives is disclosed.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a toner capable of obtaining a clear image in electrophotography. Particularly, when it is applied to color toners, it is to provide a method for producing a toner excellent in spectral characteristics such as transparency necessary for reproducing a clear color tone of a color image.

[0007]

Means for Solving the Problems The present inventors have examined a preparation method for preparing a polymerizable monomer composition containing a charge control resin composition and a polymerizable monomer. As a result, a specific flow is caused in the dispersion liquid containing the polymerizable monomer using a specific stirrer to dissolve and / or disperse the charge control resin composition in the dispersion liquid. It has been found that the dispersibility of the colorant and the coloring power and transparency of the toner can be improved, and the present invention has been completed based on this finding. Thus, according to the present invention, the charge control resin composition obtained by mixing the charge control resin and the colorant, using a stirrer that gives an axial flow, to a dispersion liquid containing a polymerizable monomer. Provided is a method for producing a toner, which comprises a step of dissolving and / or dispersing to obtain a polymerizable monomer composition, and polymerizing the obtained polymerizable monomer composition to obtain colored polymer particles.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a charge control resin composition obtained by mixing a charge control resin and a colorant is mixed with a polymerizable monomer by using an agitator which gives an axial flow. To obtain a polymerizable monomer composition by dissolving and / or dispersing in a dispersion liquid
The method includes polymerizing the obtained polymerizable monomer composition to obtain colored polymer particles.

Further, in addition to the above steps, the present invention further comprises a step of dispersing the polymerizable monomer composition in an aqueous medium containing a dispersion stabilizer, a step of washing colored polymer particles after the polymerization step, and a colored polymer. It is preferable to include a step of drying the particles, a step of classifying the dried colored polymer particles, and a step of adding an external additive to the surface of the dried or classified colored polymer particles.

In the present invention, a charge control resin composition obtained by mixing a charge control resin and a colorant is made into a dispersion liquid containing a polymerizable monomer by using a stirrer which gives an axial flow. The step of dissolving and / or dispersing to obtain a polymerizable monomer composition is included.

The stirrer used in the present invention is connected to a fluidizing portion for imparting an axial flow to the dispersion liquid containing a polymerizable monomer, and the fluidizing portion through a drive shaft or another fixed shaft. And a drive unit. In the manufacturing method of the present invention, the axial flow refers to a flow in the axial direction of the drive shaft in which the dispersion liquid is generated by the flow imparting section of the stirrer.

The stirrer used in the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual diagram of a stirrer showing an embodiment of the present invention. The stirrer 1 shown in FIG. 1 includes a motor 2 as a drive unit and a turbine 3 as a flow imparting unit.
A stator 4 that also serves as a turbine bearing and a casing 6 including a bottom plate 5 joined to the lower end surface of the stator 4 are provided on the outer circumference of the casing. The turbine 3 is connected to the motor 2 via the turbine shaft 8. A stator rod 7 is attached to the drive for holding the stator 4. Further, a commutation plate 9 is attached between the turbine shaft 8 and the stator rod 7.

As the flow of the dispersion liquid generated by the rotation of the turbine 3 of the agitator shown in FIG. 1, there are the following two types. 2 and 3 are schematic diagrams of the flow of the dispersion liquid generated by the rotation of the turbine 3 of the stirrer. The arrow in the figure indicates the flow of the dispersion liquid. In FIG. 2, the dispersion liquid is sucked into the casing 6 through the opening 5a provided at the center of the bottom plate 5 by the rotation of the turbine 3,
A shaft that is discharged to the outside of the casing through an opening 4a provided in the upper wall surface of the stator 4, collides with the commutation plate 9 to change the current, and descends along the inner wall of the stirring tank 10 to return to the bottom of the stirring tank. It becomes convection 11 in the flow direction and repeats circulation. Figure 3
In the above, due to the rotation of the turbine 3, the dispersion liquid is sucked into the inside of the casing 6 through the opening 4a provided on the upper wall surface of the stator 4, and discharged below the outside of the casing through the opening 5a provided in the central portion of the bottom plate 5. After that, it collides with the bottom of the stirring tank 10 to change the current and rises along the inner wall of the stirring tank, collides with the commutation plate 9 to further change the current, and returns to the upper part of the stator 4 with convection 11 in the axial direction. And the circulation is repeated. It should be noted that the turbine 3 determines whether the dispersion liquid is discharged outside the casing or below the casing.
It depends on the direction of rotation. Here, the upper direction outside the casing means the direction opposite to the gravity direction, and the lower direction outside the casing means the gravity direction. As an agitator having a structure as shown in FIG. K. Homomixer (made by Tokushu Kika Co., Ltd.) is mentioned.

Another embodiment of the stirrer used in the present invention is a stirrer as shown in FIG. The stirrer shown in FIG. 4 has a conical draft 12 having an inverted conical shape on the upper part of the stator, and is shaped so that a dispersion liquid, a powder to be dissolved and / or dispersed, or the like can be charged from the conical draft 12. Others are the same as those of the stirrer shown in FIG. As an agitator having a structure as shown in FIG.
K. Homogenter (made by Tokushu Kika Co., Ltd.) can be mentioned.

The charge control resin composition applicable to the present invention is obtained by mixing a charge control resin and a colorant.

The charge control resins applicable to the present invention are quaternary ammonium (salt) group-containing copolymers described in JP-A-11-15192, JP-A-3-175456, JP-A-3-243954 and the like. Coalescence and JP-A-3-243
Sulfonic acids (salts) described in JP-A No. 954, JP-A No. 1-2174464, JP-A No. 3-15858, etc.
Known resins such as group-containing copolymers can be used. The weight average molecular weight of the charge control resin applicable to the production method of the present invention is usually 2,000 to 30,000, preferably 40.
00-25,000, more preferably 6,000-2
It is 10,000. If the weight average molecular weight is less than 2,000, the viscosity at the time of kneading may be low, the colorant may not be sufficiently dispersed, and the saturation and transparency may be deteriorated. If it is too high, the viscosity becomes too high, and the dispersion may not be sufficiently performed, and the saturation and the transparency may decrease. The glass transition temperature is usually 40.
To 100 ° C, preferably 45 to 80 ° C, more preferably 45 to 70 ° C. If the temperature is lower than 40 ° C, the storage stability of the toner may be deteriorated, and if the temperature is higher than 100 ° C, the fixing property may be deteriorated.

Examples of the colorant applicable to the present invention include black colorants and color colorants. Examples of the black colorant include carbon black and nigrosine-based dyes and pigments; magnetic particles such as cobalt, nickel, ferrosoferric oxide, manganese iron oxide, zinc iron oxide and nickel iron oxide. When using carbon black,
A material having a primary particle size of 20 to 40 nm is used. If the primary particle size is smaller than 20 nm, the dispersion of carbon black cannot be obtained, and the toner has a lot of fog. On the other hand, when it is larger than 40 nm, the amount of the polyvalent aromatic hydrocarbon compound, for example, benzpyrene, increases, which may cause environmental safety problems.

The colorants for color include yellow colorants, magenta colorants and cyan colorants. As the yellow colorant, compounds such as azo pigments and condensed polycyclic pigments are used. Specifically, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 6
5, 73, 83, 90, 93, 97, 120, 138,
155, 180 and 181, 185 and 186 and the like.

As the magenta colorant, compounds such as azo pigments and condensed polycyclic pigments are used. Specifically, C.I.
I. Pigment Red 48, 57, 58, 60, 63,
64, 68, 81, 83, 87, 88, 89, 90, 1
12, 114, 122, 123, 144, 146, 14
9, 163, 170, 184, 185, 187, 20
2, 206, 207, 209 and 251, C.I. I. Pigment Violet 19 and the like.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound and the like can be used. Specifically, C.I. I. Pigment Blue 2, 3,
6, 15, 15: 1, 15: 2, 15: 3, 15: 4,
16, 17, and 60 and the like.

The amount of these colorants added is usually 10 to 200 parts by weight, preferably 20 to 150 parts by weight, based on 100 parts by weight of the charge control resin.

In the production of the charge control resin composition applicable to the present invention, an organic solvent is used if necessary. When an organic solvent is used, the charge control resin can be dissolved or swelled and kneaded, but when an organic solvent is not used, it is necessary to heat and knead the resin to a temperature at which the resin becomes soft. Further, when an organic solvent is used, particularly when the boiling point of the organic solvent is low, the organic solvent may evaporate when heated, so it is preferable to carry out at room temperature or by cooling. If the organic solvent remains in the toner, an odor problem may occur.
It is preferably removed either during the production of the charge control resin composition or during the production of the toner. The amount of the organic solvent is 0 to 100 parts by weight, preferably 5 to 80 parts by weight, and more preferably 10 to 60 parts by weight with respect to 100 parts by weight of the charge control resin.
It is the weight part, and when it is within this range, the balance between dispersibility and processability is excellent. At this time, the organic solvent may be added all at once or may be added in several divided portions while checking the kneading state.

When an organic solvent is used, its solubility coefficient (hereinafter referred to as SP value) is 8 to 15 [cal / c].
m ³ ] ^1/2 , and the boiling point is in the range of 50 to 150 ° C. If the SP value is less than 8 [cal / cm ³ ] ^1/2 , the polarity may be too small to dissolve the charge control resin, and conversely, the SP value may be 15
If it is larger than [cal / cm ³ ] ^1/2 , the polarity becomes high and the charge control resin may not be dissolved. On the other hand, if the boiling point is lower than 50 ° C, the organic solvent may evaporate due to the heat generated by the kneading, while if it is higher than 150 ° C, it may be difficult to remove the organic solvent after the kneading. Specific examples of the organic solvent (SP value / boiling point), methanol (14.5 / 65 ° C.), ethanol (10.0 / 78.3 ° C.), propanol (11.9 /
97.2 ° C), diethyl ketone (8.8 / 102 ° C),
Di-n-propyl ketone (8.0 / 144 ° C), di-i
So-propyl ketone (8.0 / 124 ° C), methyl-
n-Propyl ketone (8.3 / 102 ° C), methyl-
iso-propyl ketone (8.5 / 95 ° C), methyl-
n-butyl ketone (8.5 / 127 ° C), methyl-i
So-butyl ketone (8.4 / 117 ° C), toluene (8.9 / 110 ° C), tetrahydrofuran (9.1 /
65 ° C.), methyl ethyl ketone (9.3 / 80 ° C.), acetone (9.9 / 56 ° C.), cyclohexanone (9.9)
/ 156 ° C.) and the like, and these may be used alone or in combination of two or more kinds. Among these, considering the solubility in the charge control resin and the removal after kneading, diethyl ketone, methyl-n-propyl ketone, methyl-n-
Butyl ketone, toluene / methanol mixed solvent, toluene / ethanol mixed solvent, toluene / propanol mixed solvent, methyl ethyl ketone / methanol mixed solvent are preferable.

The kneading is carried out by using a roll, a plastic coder (manufactured by Brabender), a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.),
It can be performed using a kneader, a single screw extruder, a twin screw extruder, a Banbury, a Bus Cokneader, or the like. When an organic solvent is used, there is a problem of odor and toxicity, so a kneading machine of a closed system in which the organic solvent does not leak is preferable. Further, it is preferable that a torque meter is installed in the kneading machine because the dispersibility can be controlled by the torque level.

The charge control resin composition applicable to the present invention is obtained by adding an organic solvent to the resin composition to form a 5% resin solution, and then coating and drying the resulting film having a thickness of 30 μm and a unit area of 100 μm × The number of colorant particles having a major axis of 0.2 μm or more observed in 100 μm is usually 20 or less, preferably 10 or less, more preferably 5 or less. If this number is large, the spectral characteristics such as transparency necessary for reproducing a clear color tone of a color image may be deteriorated, fog may be increased, and the print density may be lowered. For the spectral characteristics, solid printing is performed for each color with a commercially available printer, and the color tone is measured with a spectral color difference meter.

As the polymerizable monomer applicable to the present invention,
Examples thereof include monovinyl monomers, crosslinkable monomers, macromonomers and the like.

Specific examples of the monovinyl monomer include aromatic vinyl monomers such as styrene, vinyltoluene and α-methylstyrene; (meth) acrylic acid; methyl (meth) acrylate and (meth) acrylic acid. Ethyl, propyl (meth) acrylate, butyl (meth) acrylate, (meth)
Derivatives of (meth) acrylic acid such as 2-ethylhexyl acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and (meth) acrylamide; ethylene,
Mono-olefin monomers such as propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; 2-vinyl pyridine; Nitrogen-containing vinyl compounds such as 4-vinylpyridine and N-vinylpyrrolidone; and the like. The monovinyl monomer may be used alone or in combination of a plurality of monomers. Of these monovinyl monomers, an aromatic vinyl monomer alone, a combination of an aromatic vinyl monomer and a (meth) acrylic acid derivative, and the like are preferably used.

Use of a crosslinkable monomer or a crosslinkable polymer together with the monovinyl monomer is effective for improving hot offset. The crosslinkable monomer is a monomer having two or more polymerizable carbon-carbon unsaturated double bonds. Specifically, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and their derivatives; diethylenically unsaturated carboxylic acid esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; N,
Examples thereof include compounds having two vinyl groups such as N-divinylaniline and divinyl ether, and compounds having three or more vinyl groups such as pentaerythritol triallyl ether and trimethylolpropane triacrylate. The crosslinkable polymer is a polymer having two or more vinyl groups in the polymer, and specifically, it is 2 in the molecule.
Examples thereof include esters obtained by subjecting polymers such as polyethylene, polypropylene, polyester and polyethylene glycol having at least one hydroxyl group to unsaturated carboxylic acid monomers such as acrylic acid and methacrylic acid. These crosslinkable monomers or crosslinkable polymers may be used alone or in combination of two or more. The amount used is monovinyl monomer 1
It is usually 10 parts by weight or less, preferably 100 parts by weight,
It is 0.1 to 2 parts by weight.

Further, it is preferable to use a macromonomer together with the monovinyl monomer because a good balance between storability and low-temperature fixability can be obtained. The macromonomer has a vinyl polymerizable functional group at the end of the molecular chain, and is usually an oligomer or polymer having a number average molecular weight of 1,000 to 30,000. When a polymer having a small number average molecular weight is used, the surface portion of the polymer particles becomes soft and the storage stability is deteriorated. On the contrary, when a polymer having a large number average molecular weight is used, the meltability of the macromonomer is deteriorated, and the fixability and storage stability are deteriorated. Examples of the vinyl polymerizable functional group at the end of the macromonomer molecular chain include acryloyl group and methacryloyl group,
A methacryloyl group is preferable from the viewpoint of ease of copolymerization.

Specific examples of the macromonomer applicable to the present invention include styrene, styrene derivative, methacrylic acid ester, acrylic acid ester, acrylonitrile, methacrylonitrile and the like, which may be used alone or by polymerizing two or more of them. Examples thereof include macromonomers having a polysiloxane skeleton, and among them, hydrophilic ones, particularly macromonomers obtained by polymerizing methacrylic acid esters or acrylic acid esters alone or in combination thereof are preferable. If a macromonomer is used, its amount is 1
0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, and more preferably 0.05 to 100 parts by weight.
1 part by weight. If the amount of macromonomer is small, the storage stability will not be improved. If the amount of macromonomer becomes extremely large, the fixability will decrease.

In the present invention, a releasing agent or a molecular weight adjusting agent can be contained in the dispersion liquid. Examples of the releasing agent include low molecular weight polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; plant-based natural waxes such as candelilla, carnauba, rice, wax, jojoba; paraffin, microcrystalline, petroline. Petroleum waxes such as lactams; synthetic waxes such as Fischer-Tropsch wax; and polyfunctional ester compounds such as pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, and dipentaerythritol hexamyristate. These are also one or two
A combination of two or more species can be used. The releasing agent is usually 0.5 to 100 parts by weight of the polymerizable monomer.
50 parts by weight, preferably 1 to 20 parts by weight are used.

Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide. You can These molecular weight modifiers can be added to the reaction system before the initiation of polymerization or during the polymerization. The above-mentioned molecular weight modifier is usually 0.01 to 10 parts by weight, preferably 0.1 to 100 parts by weight of the polymerizable monomer.
It is used in a proportion of 1 to 5 parts by weight.

In the present invention, the charge control resin composition obtained by mixing the charge control resin and the colorant is made into a dispersion liquid containing a polymerizable monomer by using a stirrer which gives an axial flow. A polymerizable monomer composition is obtained by dissolving and / or dispersing. An operation of dissolving and / or dispersing the charge control resin composition in a dispersion liquid containing a polymerizable monomer by using a stirrer that gives an axial flow will be described with reference to FIG.

As shown in FIG.
A dispersion liquid containing a monomer is added. And the flow of the stirrer 1
The turbine 3 of the motion imparting section is rotated to generate an axial flow in the dispersion liquid.
Grow At this time, the direction of the axial flow to be generated is
Direction (gravitational direction) of discharging the dispersion liquid from below
preferable. After this, by making the axial flow in the direction of gravity,
The charge control resin composition to be added is retained at the bottom of the stirring tank.
Dissolution efficiency is improved because it can be wound up without
To do. The direction of the axial flow generated in the dispersion liquid depends on the turbine speed.
It is possible by changing the rolling direction. Shaft generated in dispersion
Axial flow rate Q [cm ^Three/ Min] is calculated by the following formula
It Q = Nq × n × d^Three× 10⁶ In the above equation, Nq is the discharge flow coefficient [-], and n is the number of revolutions.
[rpm] and d are turbine diameters [m]. And a stirring tank
Charge control resin composition into 10. The present invention
Therefore, the charging amount of the charge control resin composition does not include the polymerizable monomer.
2 to 100 parts by weight of the dispersion liquid
40 parts by weight, more preferably 5 to 20 parts by weight.

In the present invention, when the amount of the dispersion liquid charged in the stirring tank is V [cm ³ ], stirring is preferably performed so as to satisfy the following formula.

[Formula 2] V / Q <100 When V / Q is 100 or more, the discharge capacity generated by the turbine is insufficient with respect to the amount of the dispersion liquid, so that the charge control resin composition cannot be efficiently dissolved in the dispersion liquid. Tend.

In the present invention, when the inner diameter of the stirring tank for dissolving and / or dispersing the charge control resin composition is D [m], and the turbine diameter of the flow imparting section for giving a flow to the dispersion is d [m], The d / D is preferably 0.7 or less, more preferably 0.2 or less. By setting d / D within the above range, the amount of the dispersion liquid and the flow of the dispersion liquid generated by the stirrer are well balanced, and the charge control resin composition can be efficiently dissolved and / or dispersed. FIG. 5 shows an example of measurement of the inner diameter D of the stirring tank and the turbine diameter d of the flow imparting section that imparts a flow to the dispersion liquid.

In the present invention, the polymerizable monomer composition obtained by the above method is polymerized to obtain colored polymer particles.

In the present invention, examples of the method for polymerizing the polymerizable monomer composition include suspension polymerization, emulsion polymerization and dispersion polymerization, and any method may be adopted. For example,
The polymerizable monomer composition is charged into an aqueous medium containing a dispersion stabilizer and stirred to granulate droplet particles, and in the presence of a polymerization initiator, if necessary, the temperature is raised while stirring. A method of polymerizing can be mentioned.

The dispersion stabilizer applicable to the present invention includes:
Sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; oxides such as aluminum oxide and titanium oxide; metal compounds such as aluminum hydroxide; Metal hydroxides such as magnesium hydroxide and ferric hydroxide; water-soluble polymers such as polyvinyl alcohol, methyl cellulose, gelatin; anionic surfactants, nonionic surfactants, amphoteric surfactants, etc. . Of these, a dispersant containing a metal compound, particularly a colloid of a sparingly water-soluble metal hydroxide, is preferable because it can narrow the particle size distribution of the polymer particles and improve the sharpness of the image. . Especially when the cross-linking monomer is not copolymerized, the dispersant containing the colloid of the poorly water-soluble metal hydroxide improves the dispersion stability of the colored polymer particles and the fixability and storability of the toner. It is suitable for 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. When this ratio is small, it is difficult to obtain sufficient polymerization stability and dispersion stability, and aggregates are easily generated. On the contrary, if this proportion is large, the particle size of the polymer particles becomes too fine, which is not preferable.

The aqueous dispersion may contain a water-soluble organic compound or inorganic compound in addition to the above dispersion stabilizer. Among them, the water-soluble oxo acid salt is preferable. Examples of the water-soluble oxo acid salt include borate, phosphate, sulfate, carbonate, silicate, nitrate and the like,
Among them, silicate, borate or phosphate is preferable, and borate is particularly preferable. The water-soluble oxo acid salt is usually used in an amount of 0.1 to 10 relative to 100 parts by weight of the dispersion stabilizer.
It is used in an amount of 00 parts by weight, preferably 1 to 100 parts by weight. The water-soluble oxo acid salt is dissolved and contained in the aqueous dispersion.

As the polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate; 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis [2-methyl-N- [2] -Hydroxyethyl] propionamide,
Azo compounds such as 2,2′-azobisisobutyronitrile; methylethyl peroxide, acetyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxide Examples thereof include peroxides such as oxyneodecanoate and t-butylperoxypivalate. The polymerization initiator is a polymerizable monomer 100.
0.1 to 20 parts by weight, preferably 0.
It is used in an amount of 3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight.

Polymerization of the polymerizable monomer may be carried out in one step, or in two or more steps. As a method of carrying out two or more steps of polymerization, the composition of (1) a monomer that is first polymerized (polymerizable monomer for core) and a monomer that is subsequently polymerized (polymerizable monomer for shell) is used. Instead, first, a low Tg core is formed, and then a high Tg layer (shell) is formed. (2) First, a monomer is polymerized to form particles, and then an arbitrary polymer component is added. Then, there is a method of adsorbing or fixing a polymer component on the particles. According to these methods, a core / shell type polymer particle is produced, and a so-called capsule having a good balance between low-temperature fixability and high-temperature storability is produced. It is also possible to obtain toner.

In the present invention, it is preferable to wash the colored polymer particles obtained by the above method. The post-polymerization colored polymer particles are in a dispersion state in which the colored polymer particles are dispersed in an aqueous dispersion, so the washing method is not particularly limited, but the colored polymer particle dispersion after the polymerization step is treated with an acid or Examples of the method include washing with an alkali, washing with water and dehydration.

The acid cleaning or alkali cleaning is carried out to remove a substance which is water-insoluble or poorly water-soluble in the neutral range but becomes water-soluble in the acidic or alkaline range. The method of acid or alkali washing is not particularly limited. The water washing is carried out in order to remove the water-soluble substance in the neutral region and to return the medium which has become acidic or alkaline in the acid or alkaline washing to the neutral region. Specific examples of the method of washing with water include a method of dehydrating the dispersion to form a cake, dispersing this in washing water and stirring it; a method of dehydrating the dispersion to form a cake and then spraying washing water. To be

The method for dehydrating the dispersion is not particularly limited,
For example, methods such as pressure filtration, vacuum filtration, centrifugal filtration and the like can be mentioned. Of these, the centrifugal filtration method is preferable.

Electric conductivity σ2 of the colored polymer particles after washing
Is usually 20 μS / cm or less, preferably 15 μS / c
m or less, σ2-σ1 is 10 μS / cm or less, preferably 5 μS / cm or less. The electrical conductivity σ1 of water is
Usually, it is 0 to 15 μS / cm. When σ2 is large or σ2-σ1 is large, the dependency of the charge amount on the environment becomes high, and the image quality is deteriorated due to environmental changes (changes in temperature and humidity). The electric conductivity σ2 is obtained by dispersing 6 g of the colored polymer particles in 100 g of ion-exchanged water having an electric conductivity of σ1 to obtain a dispersion, which is boiled for 10 minutes and then ion-exchanged for another 10 minutes. It is the value measured by an electric conductivity meter after adding water to restore the volume to the volume before boiling and cooling to room temperature.

When washed with acid or alkali, the pH of the colored polymer particles is usually 4-8, preferably 4.5-.
It should be 7.5. pH is 6 g of colored polymer particles
Was dispersed in 100 g of ion-exchanged water (which had been subjected to cation-exchange treatment and anion-exchange treatment), and this was boiled for 10 minutes, and then ion-exchanged water that had been boiled for another 10 minutes was added to it before boiling. It is a value measured using a pH meter after returning to weight and cooling to room temperature.

In the present invention, the washed colored polymer particles are preferably dried. The method for drying includes, for example, fluidized drying and vacuum drying, but is not particularly limited, vacuum drying capable of drying at a low temperature is preferable, and drying by a vacuum dryer equipped with a stirring blade is particularly preferable.

The dried colored polymer particles may be classified as needed and used as a toner as they are, but those obtained by adding an external additive to the surface of the dried or classified colored polymer particles are not used. Usually used as a toner.

Examples of the external additive include inorganic fine particles and organic resin fine particles. Examples of the inorganic fine particles include inorganic oxide fine particles such as silicon dioxide, aluminum oxide and titanium oxide. As the organic resin fine particles, methacrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, core / shell type polymer particles in which the core is a styrene polymer and the shell is formed of a methacrylic acid ester copolymer, etc. Is mentioned. Among these, inorganic oxide fine particles, particularly silicon dioxide fine particles are preferable.
Particularly preferred are silicon dioxide fine particles which have been further hydrophobized. The amount of the external additive is not particularly limited, but is usually 0.1 to 6 parts by weight with respect to 100 parts by weight of the colored polymer particles. Further, the external additives may be used in combination of two or more kinds. When the external additives are used in combination, it is preferable to combine two kinds of inorganic oxide fine particles or organic resin fine particles having different average particle diameters. Adhesion of external additives is
Usually, the external additive and the colored polymer particles are put in a mixer such as a Henschel mixer and stirred.

The volume average particle diameter (Dv) of the toner obtained by the present invention is usually 0.5 to 20 μm, preferably 1 to 10 μm, more preferably 2 to 8 μm. As the particle size increases, the resolution tends to decrease. The toner can be applied as a one-component developer or as a two-component developer in combination with a carrier.

[0052]

EXAMPLES The present invention will be described with reference to Reference Examples and Examples.
Although described in more detail, the present invention is not limited to the following Reference Examples and Examples. Parts and% are based on weight unless otherwise specified. The evaluation in this example is performed by the following method.

(Solubility / Dispersibility) After charging the charge control resin composition into the stirring tank containing the dispersion liquid, the dispersion liquid is taken out from the stirring tank every 15 minutes, and the charge control resin is put into the dispersion liquid and the stirring tank. Whether the composition can be confirmed or not is visually observed with a 400 × optical microscope for color shading for a maximum of 6 hours.

(Particle Size) The volume average particle size (Dv) and particle size distribution of the colored resin fine particles, that is, the ratio (Dv / Dp) of the volume average particle size to the number average particle size (Dp) is determined by Multisizer (Beckman. (Manufactured by Coulter). Aperture diameter: 100
μm, medium: Isoton II, concentration 10%, number of measured particles:
The condition is 100,000.

Production Example of Charge Control Resin Composition (Reference Example 1) Charge control resin comprising 82% styrene unit, 11% butyl acrylate unit and 7% 2-acrylamido-2-methylpropanesulfonic acid unit (weight average molecular weight 24 parts of methyl ethyl ketone and 6 parts of methanol are dispersed in 100 parts of 20,000, glass transition temperature of 65 ° C.
The mixture was kneaded with a roll while cooling to ℃. When the charge control resin is wrapped around the roll, a magenta pigment (C.I.
Pigment Red 122: manufactured by Client Co.) was gradually added and kneaded for 1 hour to produce a charge control resin composition (A1). At this time, the roll gap was initially 1 mm, then gradually widened, and finally 3 mm.
Then, the organic solvent (methyl ethyl ketone / methanol = 4/1 mixed solvent) was added several times according to the kneading state of the charge control resin. Charge control resin composition (A
After a part of 1) was taken out, toluene was added and dissolved to obtain a 5% solution of the charge control resin composition (A1) in toluene. The mixed solution was applied on a glass plate with a doctor blade having a gap of 30 μm and dried to prepare a sheet. When this sheet was observed with an optical microscope, it was 100 μm.
There were no colorant particles having a major axis of 0.2 μm or more that were present in a square.

Example 1 80.5 parts of styrene and n-
Polymerizable monomer for core consisting of 19.5 parts of butyl acrylate (Tg = 55 ° C. of copolymer obtained by copolymerizing these monomers), polymethacrylic acid ester macromonomer (Toa Synthetic Chemical Industry) Company name, product name "AA6", Tg
= 94 ° C) 0.3 part, divinylbenzene 0.5 part, t-
1.2 parts of dodecyl mercaptan were mixed to prepare a dispersion liquid containing a polymerizable monomer.

Stirrer (manufactured by Tokushu Kika Kogyo Co., Ltd., product name "T.
K. Homomixer MARKII20 type; discharge flow coefficient N
q = 0.06, put the turbine diameter d = 0.028 m "the dispersion 5,000 cm ³ to a stirring tank was installed, the turbine so dispersion is discharged in the direction of gravity from the fluidizing unit by 12,500rpm Rotated. At this time, the inner diameter D of the stirring tank and the turbine diameter d of the flow imparting section that imparts flow to the dispersion liquid
The ratio d / D was 0.08. Into this stirring tank, 10 parts of the above charge control resin composition was added to 100 parts of the dispersion liquid. In addition, the axial flow rate Q of the flow imparting section of this stirrer
[cm ³ / min] is 1.6 × 10 ⁴ [cm ³ / min]
Met. Therefore, the value of V / Q was 0.3. When the solubility was confirmed, the charge control resin composition was dissolved in 30 minutes, and there was no shade even under an optical microscope observation, and a polymerizable monomer composition A for core was obtained.

On the other hand, in an aqueous solution prepared by dissolving 9.8 parts of magnesium chloride (water-soluble polyvalent metal salt) in 250 parts of ion exchanged water, 6.9 parts of sodium hydroxide (alkali metal hydroxide) in 50 parts of ion exchanged water. An aqueous solution in which was dissolved was gradually added under stirring to prepare a magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) dispersion A. When the particle size distribution of the produced colloid was measured with a Microtrac particle size distribution measuring device (manufactured by Nikkiso Co., Ltd.), the particle size was D50.
(50% cumulative value of number particle size distribution) is 0.35 μm, D
90 (90% cumulative value of number particle size distribution) was 0.84 μm. In the measurement with this Microtrac particle size distribution measuring device, the measurement range = 0.12 to 704 μm,
The measurement was performed under the conditions of measurement time = 30 seconds and medium = ion-exchanged water.

On the other hand, 3 parts of methyl methacrylate (Tg of homopolymer = 105 ° C.) and 100 parts of water were finely dispersed by an ultrasonic emulsifier to obtain an aqueous dispersion A of the polymerizable monomer for shell. It was The particle size of the droplets of the polymerizable monomer for shell was determined by adding the obtained droplets to an aqueous solution of 1% sodium hexametaphosphate at a concentration of 3% and measuring with a Microtrac particle size distribution analyzer. It was 0.6 μm.

The polymerizable monomer composition A for cores was added to the magnesium hydroxide dispersion A obtained as described above, and the mixture was stirred until the droplets became stable, and the polymerization initiator t-butylperoxy- was added thereto. 2-ethylhexanoate (manufactured by NOF CORPORATION,
After adding 6 parts of the product name "Perbutyl O"), the mixture was agitated with high shear using an Ebara Milder (manufactured by Ebara Seisakusho) to granulate the droplets of the monomer mixture. The aqueous dispersion of the granulated monomer mixture was placed in a reactor equipped with a stirring blade,
After initiating the polymerization reaction at 0 ° C and reaching a polymerization conversion rate of almost 100%, a water-soluble initiator (manufactured by Wako Pure Chemical Industries, Ltd., trade name "VA-") was added to the aqueous dispersion A of the polymerizable monomer for shell. 086 ”=
0.3 parts of 2,2'-azobis (2-methyl-N- (2-hydroxyethyl) -propionamide) were dissolved and placed in a reactor. After continuing the polymerization for 4 hours,
The reaction was stopped by cooling to obtain an aqueous dispersion of colored polymer particles. At this time, the solid content concentration of the colored polymer particle dispersion is 2
It was 7%.

The particle size of the colored polymer particles is Dv50.
(50% cumulative value of volume particle size distribution) is 7.43 μm, D
p50 (50% cumulative value of number particle size distribution) is 6.19 μm
Met.

Sulfuric acid was added to the dispersion of the colored polymer particles until pH 4 was reached to solubilize the magnesium hydroxide on the surface of the colored polymer particles in water. Then, the obtained aqueous dispersion of core-shell type colored polymer particles was washed with sulfuric acid while stirring (25 ° C., 10 minutes), and water was separated by centrifugal filtration. Next, 500 parts of ion-exchanged water was newly added to form a reslurry, and water washing was performed. afterwards,
Again, dehydration and water washing were repeated several times to separate solids by filtration to obtain a filter cake.

The obtained filter cake was vacuum dried to obtain colored polymer particles having a volume average particle size of 6.9 μm. At this time, the water content of the colored polymer particles was 0.3% or less. To 100 parts of the obtained colored polymer particles, 0.6 part of hydrophobized colloidal silica (trade name "RX-300", manufactured by Nippon Aerosil Co., Ltd.) was added, mixed using a Henschel mixer, and externally added. The agent was attached to the colored polymer particles to obtain a toner. The results are shown in Table 1.

(Example 2) As a stirrer for dissolving and / or dispersing the charge control resin composition in Example 1, another stirrer (manufactured by Tokushu Kika Kogyo Co., Ltd., product name "TK Homogenter M type"; Discharge flow rate coefficient Nq = 0.17, turbine diameter d =
A polymerizable monomer composition for core was prepared in the same manner except that the amount was changed to 0.028 m) to obtain a toner. The results are shown in Table 1.

Comparative Example 1 As a stirrer for dissolving and / or dispersing the charge control resin composition in Example 1, a flat paddle blade having a paddle diameter of 0.12 m was used, and the rotation speed was 250 rpm.
Solubility was confirmed in the same manner except that the solution was rotated in. At this time, the flow generated from the flat paddle blade became a width flow strongly generated in the circumferential direction of the blade due to the centrifugal action due to the rotation of the paddle blade. Therefore, the charge control resin composition did not dissolve even after 6 hours, and the light and shade could be observed by optical microscope observation. The results are shown in Table 1.

Comparative Example 2 As a stirrer for dissolving and / or dispersing the charge control resin composition in Example 1, another stirrer (manufactured by Tokushu Kika Kogyo Co., Ltd., product name “TK homodisper 2.5”) was used. Solubility was confirmed in the same manner except that the rotation speed was 6000 rpm and the mold was used. At this time, the flow generated by the stirrer became a wide flow. The results are shown in Table 1.

The following can be seen from the results in Table 1. According to the method of the present invention, as in Examples 1 and 2, the charge control resin composition obtained by mixing the charge control resin and the colorant in the dispersion liquid containing the polymerizable monomer is dissolved and In the case of / or dispersion, an agitator which gives an axial flow, preferably an axial flow in the direction of gravity, can be used to efficiently dissolve and / or disperse in a short time. On the other hand, in Comparative Example, since the flow given to the dispersion liquid was not in the axial direction, the charge control resin compositions could not be dissolved even after stirring for 6 hours, and the charge control resin compositions adhered to each other by the dispersion liquid and stirred. It cannot be dissolved and / or dispersed by sticking to the bottom of the tank.

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[Table 1]

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According to the present invention, the charge control resin composition can be efficiently dissolved and / or dispersed in a dispersion liquid containing a polymerizable monomer in a short time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a stirrer used to carry out the present invention.

FIG. 2 is a schematic diagram showing an example of a flow generated in a dispersion liquid by a stirrer used for carrying out the present invention.

FIG. 3 is a schematic diagram showing another example of the flow generated in the dispersion liquid by the stirrer used for carrying out the present invention.

FIG. 4 is a schematic diagram showing another example of a stirrer used to carry out the present invention.

FIG. 5 is an example of measurement of an inner diameter D of a stirring tank and a turbine diameter d of a flow imparting unit that imparts a flow to a dispersion liquid.

[Explanation of symbols] D: Inner diameter of stirring tank d: Turbine diameter of flow imparting section that imparts flow to the dispersion liquid 1: Stirrer 2: Motor 3: Turbine 4: Stator 4a: opening 5: Bottom plate 5a: opening 6: Casing 7: Stator rod 8: Turbine shaft 9: Commutation plate 10: stirring tank 11: Convection of dispersion 12: Conical draft

Claims (3)

[Claims] 1. A charge control resin composition obtained by mixing a charge control resin and a colorant is dissolved in a dispersion liquid containing a polymerizable monomer by using a stirrer which gives an axial flow. And / or a method for producing a toner, which comprises a step of obtaining a polymerizable monomer composition by dispersing, and polymerizing the obtained polymerizable monomer composition to obtain colored polymer particles. 2. The method for producing a toner according to claim 1, wherein the axial flow direction given to the dispersion liquid containing the polymerizable monomer is the gravity direction. 3. The axial flow rate of the stirrer is Q [cm ² / min],
The method for producing a toner according to claim 1, wherein the relationship between Q and V is represented by the following relationship when the amount of the dispersion liquid is V [cm ² ]. [Equation 1] V / Q <100