JPH09288377A - Production of color toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high color development property and a wide color reproduction region of a full-color image, to improve the durability of a color toner by finely dispersing a pigment in a colorant and to attain high transparency on an OHP sheet. SOLUTION: This color toner consisting essentially of a colorant and a bonding resin is produced through a 1st process in which a wet pigment having 40-80wt.% water content and satisfying a condition represented by the formula, A/B>=400(cc/100g/μm) is kneaded with a 1st bonding resin by means of a high- speed kneader under mechanical shearing stress, the water is removed and a 2nd process kneading the resultant colorant with a 2nd bonding resin. In the formula, A is the oil absorption (cc/100g) of the pigment used in the colorant and B is the particle diameter (μm) of the wet pigment after dispersion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing color toner.

[0002]

2. Description of the Related Art In recent years, an electrostatic charge image of an original is formed by exposing it to light that has been dispersed, and then developed with three color toners (or four colors including black), and color superposition is performed to form a full color image. The obtained full-color copying method has been put into practical use, and the development of copying machines using this method has been brisk. As such colorants, organic pigment-based colorants are used from the viewpoint of light resistance, safety and the like.

However, the organic pigment-based coloring agent has a drawback that when it is in a dry powder state, it is difficult to disperse it in the binder resin used for the toner, and the organic pigment exists as an aggregate. Full-color toners are often applied to OHP (overhead projector) sheets, and are strongly required to have light transmittance. However, during full-color toner,
If the organic pigments described above are present as agglomerates, there are problems that the light transmittance, which is an important characteristic, is deteriorated, and the color reproducibility is deteriorated.

As a method for improving the dispersion of the organic pigment in the toner, Japanese Patent Laid-Open No. 62-127847 discloses a method for producing a blue toner. This method is a flushing method in which a water-containing paste of an α-phthalocyanine pigment and a solution of a binder resin in an organic solvent are heated and mixed to remove water and the organic solvent. (The colorant obtained by this method is referred to as a flushing pigment.) The light transmittance and color reproducibility of the toner produced by using the flushing pigment obtained by this method are considerably improved as compared with the toner by the conventional method. There is.

However, the α-type phthalocyanine crystal used here is liable to cause crystal growth and transition due to the unstable crystal type, and is apt to cause a decrease in coloring power and a change in hue, and a cyan toner for full-color toner. Is not preferred, and β-type phthalocyanine crystals are preferably used. Further, this method cannot be applied to yellow pigments and magenta pigments that do not rely on this method because it is a limited method such as the acid paste method and the acid slurry method. Further, this method uses an organic solvent when substituting the water in the water-containing paste, but it is difficult to recover the solvent, which is not preferable in terms of environmental hygiene. Furthermore, when the organic solvent solution of the binder resin and the water-containing paste of the pigment are mixed, since they are mixed with a kneader for kneading a high-viscosity material, suitable shear stress is not applied and pigment dispersion becomes insufficient, resulting in high concentration. It is difficult to obtain a colorant containing a pigment, and the flushing pigment becomes dough-like (dough: a soft lump-like, showing a dango state), the efficiency of the vacuum dehydration is poor, and the dehydration takes a lot of time. There's a problem.

Further, in the method described in JP-A-4-2427, a water-containing paste of an organic pigment is heated together with a binder resin, heated and mixed in a pressure kneader at a temperature of at least 100 ° C. or higher, and water is melted by the molten resin. It is stated that the unit of pigment dispersion in the toner can be controlled by producing a colorant in which the organic pigment is dispersed at a high concentration (hereinafter referred to as a melt flushing pigment) by removing and replacing it into a toner. .

However, in this case as well, JP-A-62-1
Since a pressure kneader for high-viscosity kneading is used as in the case of Japanese Patent No. 27847, when the resin is melted by heating at 100 ° C. or higher and the mixture has a low viscosity, shearing suitable for loosening pigment aggregates is performed. It is not preferable because stress is not applied, and the pigment particles become insufficiently dispersed mainly due to the action of wetting the binder resin to the pigment particles rather than the action of dispersing the pigment particles. Furthermore, the water content of the wet pigment evaporates and is lost by heating at 100 ° C. or higher, increasing the aggregates of the pigment,
It is not preferable because the pigment is dispersed in the resin in an insufficiently dispersed state.

When a pressure kneader having a large maximum power consumption is used, excessive power consumption is required to obtain the final melt flushing pigment, and the melt flushing pigment becomes dough-like and is heated at 100 ° C. or higher. However, the dehydration efficiency is poor, and it takes a lot of time for dehydration, which is a problem.

Further, the method disclosed in Japanese Patent Application Laid-Open No. 7-261460 prevents the change in molecular weight by using a linear polyester as a pigment-dispersing resin, but it is still unsuitable for fine dispersion treatment of pigments. Since the kneader is used, the dispersion of the pigment is insufficient, and the production efficiency is poor and there is a problem.

[0010]

SUMMARY OF THE INVENTION The present invention has been made as a result of the inventors' own studies in view of the above problems. That is, the object of the present invention is to achieve high color development of a full-color image and a wide color reproduction range, and to enhance the durability of the color toner by finely dispersing the pigment in the colorant, and to achieve high light transmission on the OHP sheet. It is to provide a color toner capable of exhibiting properties.

[0011]

A first invention is a method for producing a color toner comprising at least a colorant and a binder resin, and a water content of 40 to 80 w satisfying the condition of the following formula.
The first step of removing moisture by kneading t% of the wet pigment and the first binder resin by applying mechanical shear stress with a high-speed kneader, and kneading the obtained colorant with the second binder resin. The method for producing a color toner is characterized in that the second step is performed. Oil absorption amount A (cc /
100 g) and the dispersed particle size B (μm) of the wet pigment, A / B ≧ 400 (cc / 100 g / μm)

A second aspect of the present invention is characterized in that the high-speed kneader used in the first step is a vertical type high-speed kneader equipped with multi-stage blades or multi-stage stirring blades. It is a method of manufacturing a color toner.

In a third aspect, in the first step, 30
m / sec. The blade or the stirring blade is rotated at the above peripheral speed to apply mechanical shear stress.
And a method for producing a color toner according to the invention.

The fourth invention is any one of the first to third inventions, wherein the kneading temperature in the first step and / or the temperature for removing water is substantially less than 100 ° C. Or the method for producing a color toner described above.

In a fifth aspect of the invention, the first binder resin is a linear polyester resin, and the polyester resin is
Of the dihydric alcohol components constituting the polyester resin, ethylene glycol is 20 w of the total alcohol component.
The method for producing a color toner according to any one of the first to fourth inventions, which is a linear polyester resin containing t% or more.

In a sixth aspect of the invention, the second binder resin is a non-linear polyester resin, and the weight average molecular weight Mw is from 15,000 to 10,000.
60,000, number average molecular weight Mn of 20,000 to 50,000, Mw / M
n = 6.0 or more and an acid value of 15 mgKOH / g or less,
In addition, the polyester resin is a bivalent alcohol monomer, a bisphenol A-alkylene oxide adduct and an aliphatic alcohol, and a dibasic carboxylic acid derivative, terephthalic acid and isophthalic acid, and a tribasic base. A method for producing a color toner according to any one of the first to fifth inventions, which is a non-linear polyester resin containing a polymerizable carboxylic acid monomer as a constituent component.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present invention, the ratio of the oil absorption amount A (cc / 100 g) of the pigment to the dispersion average particle size B (μm) of the wet pigment is important, because the oil absorption amount shows the affinity characteristic for the first binder resin. It is presumed that if this value is high, the pigment particles are likely to migrate into the resin, and the smaller the dispersed average particle diameter of the wet pigment, the smaller the pigment dispersed particle diameter in the colorant, and the color toner that is the final product. It is presumed that the color development property and the light transmission property of are improved, and it is preferable that this ratio is high. In the present invention, A / B ≧ 400 (c
c / 100 g / μm), and preferably A / B ≧.

The wet pigment used in the colorant of the present invention does not dry the pigment produced from the aqueous phase, and it is important that the water content is in the range of 40 to 80 wt%, and particularly preferably. It is preferably in the range of 55 to 75 wt%. Water content of wet pigment is 40wt
When it is less than%, the wettability between the pigment particles and the first binder resin is deteriorated, and the pigment particles are not smoothly transferred to the resin phase, resulting in insufficient pigment dispersion. Further, as the amount of water decreases, the aggregation of pigment particles progresses, so that the dispersed particle size of the pigment becomes large, and again the pigment dispersion becomes insufficient.

On the other hand, the wet pigment has a water content of 80 wt%.
When it becomes larger, a so-called slurry state (a state containing a large amount of water) is formed at the time of kneading with the first binder resin, and suitable mechanical shear stress is not applied, and thus the pigment dispersion is also insufficient.

The oil absorption amount A of the pigment in the present invention is the oil absorption amount of a dry pigment obtained by drying a wet pigment used as a colorant. The oil absorption amount A of such a pigment is a pigment having a certain fluidity. It is expressed by the amount of boiled linseed oil required to achieve, and the number of g of boiled linseed oil or c per 100 g of pigment
It is measured by the number of c (ml) and is expressed in%. 1 g of the pigment is placed on a glass plate, and boiled linseed oil is dripped from the burette into the center of the pigment little by little and kneaded to form a solid putty-like mass.
Determine the amount of boiled flaxseed oil used and determine the oil absorption.

The dispersed average particle diameter of the wet pigment is obtained by sampling the wet pigment in a state where the pigment is dispersed in water, taking a transmission electron microscope photograph at a magnification of 30,000, and measuring the dispersed average particle diameter by an image analyzer or the like. I asked.

The wet pigment used in the colorant in the present invention has a water content of 40 to 80%, an oil absorption amount A of the pigment,
Assuming that the dispersed average particle diameter B of the wet pigment is A / B ≧ 4
Any organic pigment or carbon such as monoazo yellow, disazo yellow, carmine, rhodamine, quinacridone, phthalocyanine, anthraquinone, thioindigo, perinone, perylene, dioxazine, quinophthalone, isoindolinone, benzimidazolone, etc. Wet pigments of various pigments such as black can be used. Especially C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 122, C.I.
I. Pigment Red 57-1, C.I. I. Pigment yellow-17, C.I. I. Pigment yellow-12, C.I.
I. Pigment yellow-14, C.I. I. Pigment Bull-15-4, C.I. I. Pigment Bull-15: 3 and other wet pigments are preferably used.

In the present invention, the above-mentioned wet pigment is
In the first step, the first binder resin is added, the pigment in the wet pigment is transferred to the resin while shear-kneading with a high-speed kneader, and water is removed to obtain a colorant. The content of the pigment in the colorant is preferably in the range of 20 to 50 wt%.

The high-speed kneader used in the present invention is preferably a machine equipped with multistage blades or multistage blades. A high-speed kneading machine equipped with multi-stage blades or multi-stage blades is such that blades or upper and lower blades rotating at high speed continuously apply mechanical shearing force to the agglomerated pigment body to crush it into a shape close to primary pigment particles, and further In the color toner, pigment particles are mechanically driven into the binder resin mechanically, and microscopically adsorbed, and finally the pigment particles are transferred to the first binder resin phase by a strong stirring action. The high-speed kneader is suitable for high dispersion of the pigment, and a color toner excellent in color development and having a wide color reproducibility region can be preferably obtained.

The high-speed kneader equipped with the multistage blade or multistage blade used in the present invention includes a horizontal axis type and a vertical axis type, and the vertical axis type is preferable in the present invention.
The horizontal axis type includes turbulizer, sand turbo, paddle mixer, complex, paste mixer, etc., and the vertical axis type includes speed mixer, power kneader, rigid mixer, hybrid mixer,
Dispersive agitator, twin shaft mixer, combimix, flow jet mixer and the like can be mentioned, but preferably a vertical axis type super mixer (Kawata),
Henschel mixer (Mitsui Mining / German Henschel)
Etc. are selected as a typical example.

The peripheral speed of the multi-stage blade or multi-stage stirring blade during kneading in the first step of the present invention is preferably high, and the peripheral speed is 30 m / sec. Above, 60m / s
ec. The following is preferred. Peripheral speed 30 m / sec. When the amount is less than, the aggregated pigment body is not easily disentangled so that the color developability as a color toner is deteriorated, and further, it is difficult to sufficiently transfer the pigment particles to the resin, so that a slurry state in which water is difficult to be removed is formed. It takes time to heat and dry,
Productivity deteriorates. On the other hand, the peripheral speed is 60 m / sec. If it is larger, melting or softening of the fusion of the first binder resin due to frictional heat starts, and blades and stirring blades of a high-speed kneader,
It is not preferable because it is fused to the inner wall or the like and a suitable mechanical shearing stress is not applied, resulting in poor dispersion of the pigment or lowering the production efficiency.

In the present invention, the reaggregation of the pigment due to the evaporation of the water content of the wet pigment is prevented, and the amount of water is kept constant by the circulation of the evaporation and recooling of water in the closed type kneader to make the colorant in the tank. Is maintained in a so-called clay state (in which the water content is further reduced than in the slurry state) and shear stress is applied in a suitable range, the kneading temperature in the first step is substantially less than 100 ° C. Preferably, the glass transition temperature (Tg) of the first binder resin + 20
C. "to 95.degree. C., preferably 70.degree.
It is preferable to knead in the range of ˜95 ° C.

Glass transition temperature (Tg) of the first binder resin
Good results are obtained by performing shear kneading as described above, because the affinity between the first binder resin and the pigment particles dispersed in the wet pigment is increased by being heated to the glass transition temperature or higher, and the pigment is It is presumed that the particles are smoothly dispersed in the resin. Further, when the kneading temperature is 100 ° C. or higher, this temperature is almost close to the softening temperature of the first binder resin, so that the resin starts to be melted or softened and is fused to the blade, stirring blade, inner wall, etc. of the high speed kneader. Therefore, suitable mechanical shear stress is not applied, resulting in poor dispersion of the pigment and further lowering the production efficiency, which is not preferable.

The glass transition temperature (Tg) of the first binder resin used in the present invention is 50 to 65 ° C., preferably 55.
C. to 60.degree. C. is preferable. When the Tg is in the above range, the first binder resin having a Tg lower than 50 ° C. deteriorates the blocking property of the toner when it is used as a color toner. On the other hand, a resin having a Tg of 65 ° C. or higher has a wide molecular weight distribution, resulting in insufficient pigment dispersion.
The light transmittance of the sheet easily deteriorates.

The first binder resin in the present invention is preferably a linear polyester resin synthesized from a divalent alcohol monomer and a divalent carboxylic acid, and 20 mol% or more of all alcohol monomer components are ethylene. Desirably glycol, more preferably 30 mo
It is preferably in the range of 1% to 60 mol%. In particular, ethylene glycol is used because aliphatic alcohols are alkyl-based and alkenyl-based alcohols act as soft segments compared to aromatic alcohols. Among aliphatic alcohols, the shorter the carbon chain, the stronger the tendency. This is because it exhibits suitable properties for finely dispersing the pigment.

Other than the above-mentioned dihydric alcohol monomer components, bisphenol A ethylene oxide adducts, bisphenol A propylene oxide adducts, bisphenol A alkylene oxide adducts, etc. are suitable, and glycols other than ethylene glycol are suitable. Is mentioned. The divalent carboxylic acid monomer component is preferably composed of terephthalic acid or isophthalic acid. Other monomers include phthalic acid, fumaric acid, maleic acid and the like.

The linear polyester resin preferably used in the present invention has a weight average molecular weight Mw of from 5,000 to.
It is preferably 20,000, more preferably 5,000 to 15,000, and most preferably 7,000 to 12,000. The number average molecular weight Mn of the linear polyester resin is preferably from 10 to 60,000, more preferably from 0.
It is desirable to be in the range of 20,000 to 55,000. Weight average molecular weight is greater than 20,000, or number average molecular weight is 0.6
If it is larger than 10,000, pigment dispersion tends to be insufficient. Also,
If the weight average molecular weight is less than 5,000,000 or the number average molecular weight is less than 0.1000, the glass transition temperature of the first binder resin is lowered, and the blocking property of the toner tends to be deteriorated.

Further, the molecular weight distribution of the linear polyester resin preferable as the first binder resin is important, and in the present invention, in order to highly disperse the pigment particles in a form close to the primary particles, the molecular weight distribution Mw /Mn=3.0 or less is preferable, and Mw / Mn = 2.0 to 2.5 is more preferable. When Mw / Mn = 3.0 is exceeded, the color developability of the toner is insufficient and the light transmittance of the color image of the OHP sheet tends to be poor.

Further, the acid value of the linear polyester resin preferable as the first binder resin in the present invention is 15 mgK.
OH / g or less is preferable, and further 5 to 10 m
It is preferably gKOH / g. If the acid value of the linear polyester resin is larger than 15 mgKOH / g, it tends to absorb water, the water content in the colorant becomes large, and the toner chargeability tends to deteriorate.

The second binder resin in the present invention is preferably a non-linear polyester resin synthesized from a divalent alcohol monomer and a divalent or trivalent carboxylic acid.

As the divalent alcohol monomer component,
It is preferable to use a bisphenol A-alkylene oxide adduct such as a bisphenol A-ethylene oxide adduct and a bisphenol A-propylene oxide adduct and an aliphatic alcohol in combination. Examples of the aliphatic alcohol include ethylene glycol, diethylene glycol, triethylene glycol and the like.

Examples of the divalent carboxylic acid monomer include terephthalic acid, isophthalic acid, terephthalic acid, isophthalic acid,
Examples thereof include succinic acid, adipic acid, sebacic acid and malonic acids. Examples of the trivalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 1,2,5
-Benzenetricarboxylic acid and the like. It is preferable to use the divalent carboxylic acid monomer together with the trivalent carboxylic acid monomer.

The weight average molecular weight Mw of the non-linear polyester resin suitable as the second binder resin used in the present invention is preferably 20,000 to 60,000, more preferably 20,000 to.
The number average molecular weight Mn is preferably from 10,000 to 60,000, more preferably from 20,000 to 50,000. When the weight average molecular weight is larger than 60,000 or the number average molecular weight is larger than 60,000, the low temperature fixing property is deteriorated,
If it is small, the offset property of the toner tends to deteriorate.

Further, the preferable non-linear polyester resin as the second binder resin is the molecular weight distribution Mw / Mn = 6.
It is preferably 0 or more, more preferably Mw /
Mn = 7.0-10.0. If it is smaller than Mw / Mn = 6.0, the offset property deteriorates, and Mw / Mn = 1.
When it is 2.0 or more, the low temperature fixability tends to deteriorate.

The acid value of the second binder resin in the present invention is
It is preferably 15 mgKOH / g or less, more preferably 5 to 10 mgKOH / g. Acid value is 1
If it is larger than 5 mgKOH / g, the charging stability at high temperature and high humidity will deteriorate, and it will be difficult to obtain sufficient image quality.

In the present invention, the weight average molecular weight and the number average molecular weight of both the first binder resin and the second binder resin are commercially available gel permeation chromatography (GP).
C) was used, tetrahydrofuran was used as a solvent, the flow rate was 1.0 ml / min, room temperature, and the detector was determined by a differential refractometer (RI).

In the present invention, the acid value of both the first binder resin and the second binder resin was determined by back titration with potassium hydroxide, and the acid value was expressed in mg of KOH per gram of binder resin. .

In the present invention, the colorant obtained through the first step is crushed by adjusting the shape with three rolls of heat or the like, if necessary, and further crushed and classified through the second step. Then, various additives can be added to produce a color toner. The colorant is added in an amount of 1.5 to 15 in 100 parts by weight of the color toner.
It is preferable that it be contained by weight. If the blending amount is less than 1.5 parts by weight, the coloring power becomes weak, and if it is more than 15 parts by weight, the light transmittance of the color toner may be lowered.

Further, in the present invention, a colorless or pale color charge control agent may be added if necessary. A colorless or light-colored charge control agent is a quaternary ammonium salt, and a styrene-acrylic resin C having a sulfonic acid group introduced into the resin
CA, a boron complex, a silicon complex, a chromium complex, a zinc complex, etc. are mentioned. The amount of charge control agent added is preferably in the range of 0.2 to 10 parts by weight with respect to 100 parts by weight of the binder. Within the above range, the desired charge amount can be controlled.

Further, in the present invention, a fluidizing agent may be added if necessary. Any metal oxide may be used as long as its surface is hydrophobized, and may be used alone or in combination of two or more kinds. Examples thereof include hydrophobized silicon dioxide particles, hydrophobized titanium oxide particles, hydrophobized aluminum oxide particles, and the like. The addition amount of the fluidizing agent is preferably in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the binder resin. Further, a metal oxide or the like may be added as a resistance adjusting agent. For example, tin-based oxides, zinc-based oxides, etc. may be used, and further, metal oxides whose surface is doped with a conductive substance or whose surface is treated with a metal oxide different from the base material are used. May be.

The color toner obtained by the manufacturing method of the present invention may be pulverized by various methods.
Examples of the pulverization method include jet mill pulverization and mechanical pulverization. Further, the toner particle size is 4 to 11 μ in volume particle size.
It is preferably in the range of m, but by achieving high dispersion of the pigment according to the present invention, it can be suitably used as a so-called small particle size toner of 4 to 8 μm.

[0047]

The present invention will be described in more detail based on the following examples. Colorant Production Method-1 First Binder Resin 100 parts by weight Wet Cyan Pigment 250 parts by weight (CI Pigment Blue 15: 3, water content 60 wt%) The first binder resin is a divalent alcohol monomer component. Of which ethylene glycol is contained in an amount of 45 mol%, a weight average molecular weight Mw = 12000, and a number average molecular weight Mw = 480
0, Mw / Mn = 2.5, glass transition point 59 ° C., softening point temperature 108 ° C., acid value 8.3. Oil absorption of dried cyan pigment obtained by drying wet cyan pigment A1 = 47 cc / 1
00 g, dispersed particle size of wet cyan pigment B1 = 0.05
μm, A1 / B1 = 940. The above-mentioned first binder resin, wet cyan pigment, is a super mixer (Kawata)
At a peripheral speed of 37 m / sec. Mechanical shearing stress was continuously applied at a heating temperature of 85 ° C., the pigment was transferred to the resin and water was separated to prepare a cyan colorant a having a pigment content of 50 wt%.

Coloring agent manufacturing method-2 I. Pigment Blue 1
5-4 (oil absorption of dry pigment A2 = 35 cc / 100 g,
Dispersion particle size of wet pigment B2 = 0.08, A2 / B2 =
434, a wet cyan pigment having a water content of 60 wt%), and a cyan coloring having a pigment content of 50 wt% in the same manner as in the colorant production method-1, except that the peripheral speed was changed to 30 m / sec and the heating temperature was changed to 95 ° C. Agent b was prepared.

Colorant Production Method-3 The above-mentioned wet cyan pigment was used as C.I. I. Pigment Blue 1
5 (oil absorption of dry pigment A3 = 45 cc / 100 g, dispersed particle diameter of wet pigment B3 = 0.08, A3 / B3 = 56
3 of the wet cyan pigment having a water content of 60 wt%),
Further, a cyan colorant c having a pigment content of 50 wt% was prepared in the same manner as in the colorant production method-1 except that the peripheral speed was changed to 60 m / sec and the heating temperature was changed to 75 ° C.

Colorant Manufacturing Method-4 The above-mentioned wet cyan pigment was used as C.I. I. Pigment Blue 1
5-6 (oil absorption of dry pigment A4 = 35 cc / 100 g,
Pigment dispersion particle size of wet pigment B4 = 0.09, A4 / B
4 = 389, wet cyan pigment having a water content of 60 wt%), and a peripheral speed of 20 m / sec. A cyan colorant d having a pigment content of 50 wt% was produced in the same manner as in the colorant production method-1 except that the above was changed to.

Colorant Manufacturing Method-5 The above-mentioned wet cyan pigment was used as C.I. I. Pigment Blue 6
0 (oil absorption of dry pigment A5 = 35 cc / 100 g, dispersed particle size of wet pigment B5 = 0.1, A5 / B5 = 35
0, a wet cyan pigment having a water content of 60 wt%), and a peripheral speed of 20 m / sec. Except that it was replaced with
A cyan colorant e having a pigment content of 50 wt% was prepared in the same manner as in 4.

Colorant Manufacturing Method-6 Wet Yellow Pigment (C.I. Pigment Yellow 1
2, oil absorption of dry pigment A6 = 45 cc / 100 g, dispersed particle diameter of wet pigment B6 = 0.07, A6 / B6 = 64
3, a yellow colorant f having a pigment content of 50 wt% was prepared in the same manner as in the colorant manufacturing method-1 except that the wet yellow pigment having a water content of 60 wt% was used.

Colorant Manufacturing Method-7 I. Pigment Yellow 17 (oil absorption of dry pigment A7 = 50 cc / 100 g,
Dispersion particle size of wet pigment B7 = 0.1, A7 / B7 = 5
00, wet yellow pigment having a water content of 60 wt%), and a yellow colorant g having a pigment content of 50 wt% was prepared in the same manner as in the colorant production method-1.

Coloring Agent Manufacturing Method-8 I. Pigment Yellow 81 (dry pigment oil absorption A8 = 50 cc / 100 g,
Dispersion particle size of wet pigment B8 = 0.2, A8 / B8 = 2
50, a yellow colorant h having a pigment content of 50 wt% was prepared in the same manner as in Colorant production method-1 except that a wet yellow pigment having a water content of 60 wt% was used.

Colorant Manufacturing Method-9 The above-mentioned wet yellow pigment was used as C.I. I. Pigment Yellow 154 (oil absorption of dry pigment A9 = 40 cc / 100)
g, dispersed particle size of wet pigment B9 = 0.4, A9 / B9
= 100, wet yellow pigment with a water content of 60 wt%)
A yellow colorant i having a pigment content of 50 wt% was produced in the same manner as in the colorant production method-1 except that the above was changed to.

Colorant Manufacturing Method-10 First Binder Resin 100 parts by weight Wet Magenta Pigment 250 parts by weight (CI Pigment Red 57-1, water content 60 wt%) The first binder resin is a divalent alcohol. 30 mol% of ethylene glycol is contained among the monomer components, the weight average molecular weight Mw = 9000, the number average molecular weight Mw = 3500, M
w / Mn = 2.6, glass transition point 57 ° C., softening point temperature 1
It has an acid value of 6.1 at 08 ° C. Oil absorption of dry magenta pigment when wet magenta pigment is dried A10 = 70c
c / 100g, wet magenta pigment dispersion particle size B10
= 0.1 μm and A10 / B10 = 700. The above-mentioned first binder resin and wet magenta pigment are continuously applied with a mechanical mixer at a peripheral speed of 47 m / sec and a heating temperature of 90 ° C. with a super mixer (Kawata Manufacturing Co., Ltd.) to transfer the pigment to the resin to remove water. Separated, a magenta colorant j having a pigment content of 50 wt% was prepared.

Coloring Agent Manufacturing Method-11 The wet magenta pigment is mixed with C.I. I. Pigment Red 122 (oil absorption of dry pigment A11 = 45 cc / 100
g, dispersed particle size of wet pigment B11 = 0.1, A11 /
Pigment content 50 wt% in the same manner as Colorant Production Method-10 except that B11 = 450 and water content 60 wt% wet magenta pigment satisfying the condition of A / B ≧ 400.
% Magenta colorant k was prepared.

Colorant Manufacturing Method-12 The wet magenta pigment was used as C.I. I. Pigment Red 48-1 (oil absorption of dry pigment A12 = 55 cc / 100
g, dispersed particle size of wet pigment B12 = 0.05, A12
/ B12 = 1100 and a water content of 60 wt% wet magenta pigment which satisfies the condition of A / B ≧ 400), except that the pigment content is 5 in the same manner as in Colorant Production Method-10.
A 0 wt% magenta colorant 1 was prepared.

Coloring Agent Manufacturing Method-13 The wet magenta pigment is mixed with C.I. I. Pigment Red 48-3 (oil absorption of dry pigment A13 = 55 cc / 100
g, dispersed particle size of wet pigment B13 = 0.2, A13 /
Pigment content 5 in the same manner as in Colorant manufacturing method-10, except that B13 = 275 and a moisture content of 60 wt% wet magenta pigment that does not satisfy the condition of A / B ≧ 400 are replaced.
A 0 wt% magenta colorant m was prepared.

Coloring Agent Manufacturing Method-14 The wet magenta pigment is mixed with C.I. I. Pigment Red 31 (dry pigment oil absorption A14 = 75 cc / 100 g,
Dispersion particle size of wet pigment B14 = 0.2, A13 / B1
3 = 375, and a pigment content of 50 wt% was obtained in the same manner as in Colorant Production Method-10, except that the moisture content was 60 wt% wet magenta pigment which did not satisfy the condition of A / B ≧ 400.
% Magenta colorant n was prepared.

The colorants a to c, f to g, and j to 1 were obtained in a state in which the pigment was dispersed well and the color was excellent. The colorants d, e, h, i, m, and n are poor in color dispersion due to insufficient pigment dispersion, and insufficient drying of water due to insufficient separation of water, leading to the quality and production efficiency as a colorant. There was a problem. Table 1 shows the results.

[Example 1] Second binder resin 95 parts by weight Cyan colorant a 5 parts by weight The second binder resin has a weight average molecular weight Mw of 30,000, a number average molecular weight Mn of 30,000 and Mw. /Mn=10.0, Tg = 5
6 ° C., softening point 110 ° C., acid value 8.0, monomer component is bisphenol A-propylene oxide adduct,
Ethylene glycol, terephthalic acid and trimellitic acid were used. After mixing the above components with a Henschel mixer, they were melt-kneaded with an extruder, pulverized with a jet mill and classified to prepare a cyan toner A having a pigment content of 2.5 wt% and a volume average particle diameter of 8 μm.

Example 2 A cyan toner B having a pigment content of 2.5 wt% and a volume average particle size of 8 μm was prepared in the same manner as in Example 1 except that the cyan colorant a was replaced with the cyan colorant b. . [Example 3] The pigment content was 2.5 wt% in the same manner as in Example 1 except that the cyan colorant a was replaced with the cyan colorant c.
%, And a cyan toner C having a volume average particle diameter of 8 μm was manufactured.

Comparative Example 1 A cyan toner D having a pigment content of 2.5 wt% and a volume average particle diameter of 8 μm was prepared in the same manner as in Example 1 except that the cyan colorant a was replaced with the cyan colorant d. .

Comparative Example 2 A cyan toner E having a pigment content of 2.5 wt% and a volume average particle size of 8 μm was prepared in the same manner as in Example 1 except that the cyan colorant a was replaced with the cyan colorant e. .

[Example 4] The pigment content was 3.0 wt% and the volume was the same as in Example 1 except that the cyan colorant a was replaced by 6 parts by weight of the yellow colorant f and the binder resin was changed to 94 parts by weight. A yellow toner F having an average particle size of 8 μm was produced.

Example 5 A yellow toner G having a pigment content of 3.0 wt% and a volume average particle diameter of 8 μm was produced in the same manner as in Example 4 except that the yellow colorant f was replaced with the yellow colorant g. .

Comparative Example 3 A yellow toner H having a pigment content of 3.0 wt% and a volume average particle size of 8 μm was prepared in the same manner as in Example 4 except that the yellow colorant f was used instead of the yellow colorant f. did.

[Comparative Example 4] Yellow-Colorant f was yellow-
A yellow toner I having a pigment content of 3.0 wt% and a volume average particle diameter of 8 μm was produced in the same manner as in Example 4 except that the colorant i was used.

Example 6 The pigment content was 5.0 wt% in the same manner as in Example 1 except that the cyan colorant a was replaced by 10 parts by weight of the magenta colorant j and the binder resin was changed to 90 parts by weight.
A magenta toner J having a volume average particle diameter of 8 μm was manufactured.

Example 7 A magenta toner K having a pigment content of 5.0 wt% and a volume average particle diameter of 8 μm was produced in the same manner as in Example 6 except that the magenta colorant j was replaced with the magenta colorant k. .

Example 8 A magenta toner L having a pigment content of 5.0 wt% and a volume average particle size of 8 μm was prepared in the same manner as in Example 6 except that the magenta colorant j was replaced with the magenta colorant l. .

Comparative Example 5 A magenta toner M having a pigment content of 5.0 wt% and a volume average particle diameter of 8 μm was prepared in the same manner as in Example 6 except that the magenta colorant j was replaced with the magenta colorant m. .

Comparative Example 6 A magenta toner N having a pigment content of 5.0 wt% and a volume average particle diameter of 8 μm was produced in the same manner as in Example 6 except that the magenta colorant m was replaced with the magenta colorant n. .

To 100 parts by weight of each of the toners of Examples 1 to 8 and Comparative Examples 1 to 6, 0.2 parts by weight of hydrophobic silica and 0.6 parts by weight of hydrophobic titania were externally added, and a styrene-acrylic resin was added. Table 2 shows the results of image evaluation with a commercially available digital full-color copying machine by mixing with the coated ferrite carrier to prepare a developer.

Here, the coloring property is evaluated by the ID when the unfixed image transferred on the paper has a fixed toner adhesion amount, and the pigment content rate (when 100 parts by weight of toner is used). The value obtained by dividing by the ratio (part by weight of pigment) was expressed as a color forming index. Specifically, cyan toner is 0.7 mg
/ Cm ^2, the magenta toner 0.8 mg / cm ^2, yellow toner 0.65 mg / cm ² and then ID Macbeth densitometer when the (RD918: manufactured by Macbeth Co.) was measured,
Cyan toner 0.025 and magenta toner 0.0, respectively
5 and yellow toner 0.03. Color development index = image density ID of each color toner / pigment content rate of each color toner, where ID is a value when the fixed adhesion amount of each color toner is used.

The color reproducibility was evaluated by copying 20,000 sheets using an original document having an image area of 50% with the above-mentioned commercially available digital full-color copying machine and evaluating the image. OHP series
For the evaluation of transparency of the color image produced by the above-mentioned method, the transmission image when projected by an overhead projector was visually judged.

When each of the toners of Examples 1 to 8 was imaged, a color image having excellent coloring properties was obtained, and the transparency of the color image of the OHP sheet was also excellent. Comparative Examples 1 to 6
The image density of each of the toners was lower than that of the example, and only an image with poor color reproducibility was obtained. OHP
The color image on the sheet was dull in color and poor in transparency.

[0079]

[Table 1]

[0080]

[Table 2]

By the method for producing a color toner of the present invention, a color toner in which a pigment is finely dispersed in a binder resin can be obtained, and color reproduction is caused by the fact that the aggregation of pigment particles in the toner is very small. It has become possible to provide a color toner having excellent properties, color development and light transmission.

Claims (6)

[Claims] 1. A method for producing a color toner comprising at least a colorant and a binder resin, wherein a wet pigment having a water content of 40 to 80 wt% and a first binder resin are machined by a high speed kneader. A method for producing a color toner, characterized by passing through a first step of kneading by applying dynamic shear stress to remove water, and a second step of kneading the obtained colorant with a second binder resin. . When the oil absorption amount A (cc / 100 g) of the pigment used for the colorant and the dispersed particle size B (μm) of the wet pigment are used, A / B ≧ 400 (cc / 100 g / μm) 2. The method for producing a color toner according to claim 1, wherein the high-speed kneader used in the first step is a vertical type high-speed kneader equipped with multi-stage blades or multi-stage stirring blades. . 3. In the first step, 30 m / sec.
3. The method for producing a color toner according to claim 2, wherein the blade or the stirring blade is rotated at the above peripheral speed to apply mechanical shear stress. 4. The method for producing a color toner according to claim 1, wherein the kneading temperature in the first step and / or the temperature for removing water are substantially less than 100 ° C. . 5. The first binder resin is a linear polyester resin, and the polyester resin comprises ethylene glycol in an amount of 20 wt% of all alcohol components in the divalent alcohol component constituting the polyester resin. The method for producing a color toner according to any one of claims 1 to 4, which is a linear polyester resin containing the above. 6. The second binder resin is a non-linear polyester resin, having a weight average molecular weight Mw of 15,000 to 60,000, a number average molecular weight Mn of 20,000 to 50,000, and Mw / Mn = 6. 0 or more and an acid value of 15 mgKOH / g or less, and the polyester resin as a divalent alcohol monomer is a bisphenol A-alkylene oxide adduct and an aliphatic alcohol, and a dibasic carboxylic acid. 6. A method for producing a color toner according to claim 1, which is a non-linear polyester resin having terephthalic acid and isophthalic acid as acid derivatives and a tribasic carboxylic acid monomer as constituent components. .