JP2002287421A - Method for manufacturing toner, master batch pigment, color toner, method for manufacturing color toner, method for forming image and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the coloring degree and transparency as well as to obtain electrification stability in a high temperature environment. SOLUTION: The toner is prepared by using a dry powdery pigment as the pigment and by adding water to mix the dry powdery pigment and a binder resin to obtain a mixture, then heating and kneading the mixture to remove the water added during mixing. The mixture is kneaded in such a manner that the mixture shows 0.01 to 5.0% weight reduction by drying at 110 deg.C and <=0.5% weight reduction by drying at 70 deg.C after kneaded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a toner, and a masterbatch pigment used as a colorant for plastics or the like, in which a pigment is dispersed in a resin at a pigment concentration higher than the pigment concentration in a final product. More particularly, the present invention relates to a method for producing a master batch pigment for a toner used for a toner for electrostatic charge development produced by a melt-kneading and pulverizing method, and a master batch pigment for a toner.

[0002]

2. Description of the Related Art Toners used in a dry developing method mainly comprise a thermoplastic resin (binder resin), a dye / pigment (colorant), a release agent, and the like, and if necessary, a magnetic powder and a charged toner. It is manufactured by adding a control agent, a fluidity improver and the like. And
As a method for producing these toners, see JP-A-1-304.
No. 467, all materials are mixed at once and heated, melted and dispersed by a kneader or the like to form a uniform composition, which is then cooled, pulverized and classified to obtain a volumetric composition. A method for producing a toner having an average particle size of about 6 to 10 μm is generally adopted.

[0003] In particular, an electrophotographic color toner used for forming a color image is generally formed by dispersing various chromatic dyes or pigments in a binder resin.
In this case, the performance required for the toner to be used is stricter than that for obtaining a black image. In other words, in addition to mechanical and electrical stability against external factors such as shock and humidity, the toner exhibits proper color development (coloring degree) and light transmittance (transparency) when used in an overhead projector (OHP). )Is required.

[0004] Examples of the use of a dye as a colorant include:
For example, JP-A-57-130043 and JP-A-57-130043
There is one described in JP-A-130044. Thus, when a dye is used as a colorant, the resulting image is excellent in transparency, and it is possible to form a clear color image with good coloring properties, but on the other hand, light resistance is inferior, and under direct light If left undisturbed, there is a problem of discoloration and fading.

[0005] In this respect, when a pigment is used as a coloring agent,
Pigment-based color toners have excellent light fastness. For example,
JP-A-49-46951, JP-A-52-1702
There is one described in Japanese Patent Publication No. However, although pigment-based color toners are excellent in light resistance, on the other hand, there is a problem that the degree of coloring (color-forming property) and the transparency are inferior due to poor dispersibility of the pigment in the binder resin.

Therefore, the following methods have been proposed as methods for improving the dispersibility of the pigment in the binder resin. (1) In JP-A-62-280755, a polyester resin (resin A) is used as a binder resin, and a pigment is previously coated with a polyester resin (resin B) having a higher molecular weight than the resin A, and the coated resin is coated. A technique of dispersing a pigment in a resin A to obtain a color toner is described. (2) Japanese Patent Application Laid-Open No. 2-266561 discloses that a processed pigment obtained by melt-kneading a resin and a pigment resin is dispersed and contained in a binder resin, and the weight average molecular weight of the pigment resin is Is smaller than the weight average molecular weight of the binder resin, and the weight average molecular weight of the binder resin is 100,000 or more. (3) JP-A-9-101632 discloses that a mixture of a binder resin and a pigment is first kneaded together with an organic solvent at a temperature lower than the melting temperature of the binder resin, and then the binder resin and the charged resin are charged. in addition a control agent to obtain a color toner by heating and melting and kneading the 2-stage technique is described. (4) JP-A-4-39671 discloses a toner comprising a binder resin having a weight-average molecular weight of 40,000 or less and a coloring agent comprising a flushing pigment using the binder resin. ing. (5) JP-A-4-230770 discloses that a solvent, a first binder resin soluble in the solvent and particles of a colorant insoluble in the solvent are mixed, and a temperature of 50 to 100 is applied under a pressurized condition. ° C,
After dispersing the colorant particles in the binder resin while applying a shearing force, the solvent is removed to obtain a colored binder resin composition in which the colorant particles are dispersed. A technique is disclosed in which a toner is obtained by adding a charge control agent and kneading and heat-kneading a second stage.

However, the above-mentioned (1) JP-A-62-2
No. 80755 or (2) JP-A-2-66561 cannot sufficiently disperse the pigment, and at present, the coloring degree and the transparency are inferior.
In addition, (3) JP-A-9-101632,
(4) JP-A-4-39671, (5) JP-A-4-39671
The method as claimed in any of JP 230770 discloses, although the dispersion of the pigment is improved due to the use of any of the methods solvents, some even in trace amounts or the toner in the product as was much remove solvent but a solvent It has recently been found that this reduces the charge amount of the toner in a special environment such as use in a high-temperature environment and causes problems such as toner scattering in the developing section.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a masterbatch pigment and a masterbatch pigment capable of improving both the degree of coloring and transparency and the charge stability in a high-temperature environment. An object of the present invention is to provide a production method, and to provide a toner using the master batch pigment.

[0009]

Means for Solving the Problems The present inventors have investigated the cause of the problem such as toner scattering in the developing section in a high temperature environment, and found that a small amount of solvent component remaining in the toner reduces the charge amount of the toner. It turned out to be the cause. Where the toner manufacturing method according to the present invention is a method for producing a toner using a master batch kneading of dispersing the pigment in the resin, using a dry powder pigment as the pigment, the dried powder pigment and a binder resin The mixture obtained by adding water at the time of mixing is heated and kneaded to remove the water added at the time of mixing.
And 0.01 to 5.0% and loss on drying at 70 ° C. is characterized by kneading so as to be 0.5% or less.

[0010] The method for producing a toner according to the present invention comprises:
A master batch kneading step of melt-kneading a raw material mixture containing at least a binder resin, a pigment, and water, and a kneaded product obtained in the master batch kneading step being the same or different so that the desired pigment concentration of the toner is obtained. Having a dilution kneading step of diluting with a binder resin, a method of producing a color toner by pulverizing the kneaded material obtained in the dilution kneading step,
A dry powder pigment is used as the pigment used in the master batch kneading step, and the mixture obtained by adding water when mixing the dry powder pigment and the binder resin is heated and kneaded to add water added at the time of mixing. Of the toner obtained by kneading
The kneading is performed so that the loss on drying at 70 ° C is 0.01 to 5.0% and the loss on drying at 70 ° C is 0.5% or less.

Further, the loss on drying at 110 ° C. is 0.01 to 1.
It is preferable to knead the mixture so that the amount is 0% and the loss on drying at 70 ° C. is 0.05% or less. In the master batch pigment kneading step, the pigment content is 40 to 60.
% By weight. In the master batch pigment kneading step, the amount of water added during mixing is preferably 10 to 50% by weight. In the master batch pigment kneading step, the electric conductivity is 1.
It is preferable to use water of 0 μS or less. In the master batch pigment kneading step, the saturated water supply rate is 20%.
It is preferable to use a pigment that is 100% to 100%. Also,
In the master batch pigment kneading step, it is preferable to use a polyol resin as the binder resin. In the master batch pigment kneading step, it is preferable to use a polyester resin as the binder resin.

It is preferable to use an open-type kneader as the kneader used in the master batch pigment kneading step. Further, the set temperature (T) of the kneader is determined by adjusting the temperature at which the binder resin flows out (Tr). ) Is preferably a temperature condition satisfying the following expression. 80 <Tr <110 (° C) Tr-20 <T <Tr + 50 (° C)

Further, the outflow start temperature (Tm) after kneading the master batch is determined by the outflow start temperature (Tr) of the binder resin.
It is preferable to knead the mixture so as to satisfy the following formula. 80 <Tr <110 (° C) Tm> Tr + 20 (° C)

The masterbatch pigment according to the present invention comprises 110
It is characterized in that the loss on drying at ℃ is 0.01 to 5.0% and the loss on drying at 70 ° C is 0.5% or less. The masterbatch pigment according to the present invention has a loss on drying at 110 ° C. of 0.01 to 1.0% and a loss on drying at 70 ° C. of 0.1%.
It is characterized by being less than 05%. Further, the master batch pigment according to the present invention is obtained by the above-described method for producing a toner.

Further, the color toner according to the present invention is prepared by diluting and kneading the above-mentioned master batch pigment with the same or different binder resin so as to obtain a desired pigment concentration of the toner.
Obtained by grinding the resulting kneaded product.

Further, the method for producing a color toner according to the present invention includes a dilution kneading step of diluting the master batch pigment with the same or different binder resin so as to obtain a desired pigment concentration of the toner. The kneaded product obtained in the dilution kneading step is pulverized.

An image forming method according to the present invention is characterized in that the color toner is used. An image forming apparatus according to the present invention uses the color toner.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a toner production method, a masterbatch pigment and a masterbatch production method according to the present invention will be described in more detail. The toner to be used in the present invention is a toner using a pigment as a colorant, and is applicable to all toners (color toner, black toner) manufactured by a usual melt-kneading and pulverizing method.

In the masterbatch pigment of the present invention, a dry powder pigment is used as a pigment, and a mixture obtained by adding water when mixing the dry powder pigment and the binder resin is heated and kneaded to be added at the time of mixing. Of the toner obtained by kneading, the loss on drying at 110 ° C after kneading is 0.01 to 5.0%, and the loss on drying at 70 ° C is 0.5% or less, preferably 110% or less.
The most characteristic feature is that kneading is performed so that the loss on drying at 0 ° C is 0.01 to 1.0% and the loss on drying at 70 ° C is 0.05% or less. By doing so, the dispersibility of the pigment is significantly improved, and at the same time, 70 ° C
A masterbatch pigment having a small amount of weight loss in a relatively low temperature range, and a toner using the masterbatch pigment.

In the first place, the pigment has a primary particle of 0.001 to
Although it is as small as 0.1 μm, it forms large aggregates several μm in size when the raw material is in the form of dry powder.
The ideal dispersion of the pigment is to disintegrate this agglomerate and disintegrate it into primary particles.
Making the primary particles of 001 to 0.1 μm smaller than that is a limit in the kneading method by such ordinary mechanical repetitive shearing. That is, poor dispersion of the pigment is nothing other than the inability to break up the aggregate. The prerequisite for the agglomerate to be broken is that the surrounding resin penetrates into the voids inside the agglomerate and efficiently wets all primary particle surfaces. Therefore, the point of pigment dispersion lies in whether the surrounding resin can enter the voids inside the aggregate. However, since the binder resin used in ordinary toners has a high melt viscosity, it requires a large amount of energy to penetrate into the aggregates. It is.

The present invention is characterized in that water is used as a method for wetting the dry powder pigment. Organic pigments generally used as colorants are hydrophobic, but the manufacturing process involves washing and drying, so that if some force is applied, water will penetrate into the pigment aggregates. It is possible. A mixture of a pigment and a resin in which water has penetrated into the agglomerate is mixed with an open kneader.
The temperature of the kneaded material where the maximum shear force of the kneaded material is applied is
When kneading at a temperature of 100 ° C. or higher, the water inside the aggregate reaches the boiling point instantaneously and almost explosively expands in volume, so that a force for breaking the aggregate from inside the aggregate is applied. The force from the inside of the aggregate can disintegrate the aggregate very efficiently compared to the force applied from the outside.

Further, at this time, since the resin is heated to a temperature higher than the softening point, the viscosity is lowered, and the aggregate is efficiently wetted, and at the same time, water close to the boiling point inside the aggregate is so-called. By being replaced by an effect similar to flushing, a master batch pigment in which the pigment is dispersed in a state close to the primary particles can be obtained.

Further, the absorption of water by the pigment aggregates in the pigment mixing step prior to kneading is an exothermic reaction process, ie, a process of releasing the internal latent heat of the pigment. At this stage, heat is generated and the energy becomes more stable, Also, in the process of evaporating water, the heat of vaporization accompanying the evaporation of water is removed from the kneaded material, so that the temperature of the kneaded material is maintained at a relatively low temperature and high viscosity, so that the shearing force is effectively applied to the pigment aggregate. also it has combined effect that is added to.

Further, in the present invention, the reason why water having low affinity for the pigment or the resin is used is that it is not preferable that a large amount of components such as solvent and water remain in the master batch pigment after the dispersion treatment. is there.

Therefore, it is necessary to remove the added water or solvent when heating and kneading with the open-type kneader. At this time, the boiling point is lower than when a solvent having high affinity for the resin or pigment is used. Even if it is high, it can be easily removed by using water having low affinity for the resin and the pigment.

Further, since a solvent usually used here has a high affinity with a charge control agent used in a toner,
Even when a very small amount is present in the toner, the solvent in the toner moves / diffuses / evaporates under a special condition of a high temperature environment, which causes a problem that the charge amount is reduced.

In the present invention, the kneading method using water is as follows.
This is a technique clearly different from the flushing method using a surfactant which is often used in the ink field. In the masterbatch process required in the toner field, not only the dispersibility of the pigment but also all the qualities of the final toner must be maintained in a well-balanced manner. In many cases, there is a problem in charging stability when a copying machine is used continuously for a long time, and the present invention is an effective method for solving such a problem.

Further, in the master batch kneading step of the present invention, the pigment content is 40 to 60% by weight, preferably 50 to 60% by weight. When the pigment content is 40% by weight or less, the melt viscosity at the time of kneading decreases, so that an effective shearing force is not applied to the pigment. When the pigment content is 60% by weight or more, there is no resin sufficient to wet all the pigment surfaces. The pigment no longer disperses.

The water to be added in the masterbatch kneading step of the present invention has an electric conductivity of 1.0 μS or less, and the amount thereof is 10 to 50% by weight, preferably, an addition amount that matches the saturated water supply amount of the pigment. It is. Electric conductivity is 1.0
Above μS, there is a problem in the charging characteristics of the toner. On the other hand, if the amount of water added is 10% by weight or less, the amount of water enough to enter all the pigment aggregate voids is not enough, and the intended effect cannot be obtained. On the other hand, when the content is 50% by weight or more, most of the energy is used for evaporating water, and the effect of disintegration from the inside of the aggregate due to the explosive expansion of the present invention is hardly obtained.

The measurement of the saturated water supply rate in the present invention is based on JIS
Performed according to K5101. However, water was used in place of linseed oil, and it was difficult to treat on a glass plate. Therefore, the method was performed in a sealed plastic bag. The saturated water supply rate here is the amount of water that can be supplied in 10 g of the pigment,
A saturated water supply rate of 100% indicates a state where 10 g of water is supplied.

As the kneader used in the present invention, an open kneader is desirable. In the closed kneader, water removal intended by the present invention cannot be efficiently performed. As the open-type kneader, a method using a Banbury mixer as an open type, a continuous two-roll kneader manufactured by Mitsui Mining Co., Ltd. or the like can be used in addition to the usual two-roll or three-roll.

The pigment used in the present invention preferably has a saturated water supply rate of water of 20 to 100%. If the saturated water supply rate is 20% or less, the primary particle size of the pigment is too large to be suitable as a toner, or water cannot enter the pigment aggregate. On the other hand, if the amount is more than 100%, the amount of water becomes too large.

Specific examples of the pigment include the following. As black pigments, carbon black,
Examples include azine dyes such as oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides. Examples of the yellow pigment include cadmium yellow, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hanza yellow G, Hanza yellow 10G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake. . Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK. Red pigments include Bengala,
Cadmium Red, Permanent Red 4R, Risor Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B,
Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B. Examples of purple pigments include Fast Violet B and Methyl Violet Lake. Examples of blue pigments include cobalt blue, alkali blue, Victoria Blue Lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, and indanthrene blue BC. Green pigments include chrome green, chromium oxide, pigment green B, malachite green lake, and the like. These are all dry powder pigments, and one or two
More than seeds can be used.

Further, the set temperature (T) of the kneader in the master batch kneading step of the present invention is as follows, when the outflow start temperature of the binder resin is (80 <Tr <110 (° C.)).
It is desirable to knead under the temperature condition satisfying the formula: Tr−20 <T <Tr + 50 (° C.). Tr is (Tr-20) ° C
Under the following conditions, the temperature of the kneaded material is too low, so that it is difficult to remove water from the master batch. At (Tr + 50) ° C. or higher, water can be removed. , The shearing force is not effectively applied to the pigment aggregate.

Further, the outflow start temperature (Tm) after kneading the master batch is determined by setting the outflow start temperature of the binder resin to (80 <T
When r <110 (° C.), the formula: Tm> Tr + 20
(° C.). Tm is (Tr + 20)
If the temperature is lower than ℃, the dispersion of the pigment is poor and the thermal characteristics of the binder resin itself are affected. Note that Tm decreases as the pigment content in the master batch decreases. In the present invention, the outflow starting temperature is measured using an elevated flow tester (CFT-500, manufactured by Shimadzu Corporation) with a die diameter of 0.5 m.
m, the pressure 10 kgf / cm ^2, was measured at a Atsushi Nobori rate of 3 ° C. / min.

The masterbatch pigment obtained according to the present invention has a loss on drying at 110 ° C. of 0.01 to 5.0%, preferably 0.1%.
It is preferably from 01 to 1.0%, and the loss on drying at 70 ° C is preferably 0.5% or less, more preferably 0.05% or less. When the loss on drying at 110 ° C. is 5.0% or more, not only does the water present in the masterbatch affect the quality, but also the dispersion of the pigment becomes poor due to insufficient shearing during kneading the masterbatch. On the other hand, the loss on drying at 110 ° C is
In order to reduce the content to 0.01% or less, excessive kneading and kneading must be performed during kneading of the master batch, so that there is a problem that a part of the binder resin is sheared and low molecular weight components increase. Further, if the loss on drying at 70 ° C. is 0.5% or more, there is a problem that when the toner is used, the charge amount decreases when used in a high-temperature environment.

In the present invention, the loss on drying is determined by first sieving with a sieve having openings of 0.15 mm and 2.0 mm in order to adjust the particle size of the sample.
After leaving it to stand at a predetermined drying temperature for 2 hours and then cooling it in a desiccator for 0.5 hour, the weight loss was determined. As the binder resin for the master batch used in the present invention and the binder resin for dilution when used as a toner, conventionally known binder resins can be widely used. For example, a vinyl resin, a polyester resin, or a polyol resin may be mentioned, and among them, a polyester resin or a polyol resin is preferably used.

As the vinyl resin, styrene such as polystyrene, poly-P-chlorostyrene, polyvinyltoluene, and a homopolymer of a substituted product thereof: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyl Toluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylic acid Methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer Styrene-based copolymers such as polymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyacetic acid Vinyl etc. That.

Examples of the polyester resin include those comprising a dihydric alcohol as shown in Group A below and a dibasic acid salt as shown in Group B, and a trivalent alcohol as shown in Group C below. The above alcohol or carboxylic acid may be added as the third component. Group A: ethylene glycol,
Triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4 butanediol, neopentyl glycol, 1,4 butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated Bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene (2,2) -2,2'-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3)-
2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -2,2′-bis (4-hydroxyphenyl) propane and the like. Group B: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, linoleic acid, or Esters of these acid anhydrides or lower alcohols. Group C: tri- or higher-valent alcohols such as glycerin, trimethylolpropane, and pentaerythritol; and tri- or higher-valent carboxylic acids such as trimellitic acid and pyromellitic acid.

Examples of the polyol resin include an alkylene oxide adduct of an epoxy resin and a dihydric phenol or a compound having one active hydrogen in the molecule that reacts with the glycidyl ether and the epoxy group, and an active hydrogen that reacts with the epoxy resin. Examples thereof include compounds obtained by reacting two or more compounds in a molecule.

In addition, the following resins can be mixed and used as required. For example, epoxy resin, polyamide resin, urethane resin, phenol resin, butyral resin, rosin, modified rosin, terpene resin, and the like. Epoxy resins include bisphenol A and bisphenol F such as bisphenol A and epichlorohydrin. Condensates are typical.

When the present invention is used as a toner, a charge control agent can be blended (internally added) with toner particles or mixed (externally added) with toner particles. The charge control agent makes it possible to control the amount of charge optimally according to the development system. Examples of the charge control agent include nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (see Japanese Patent Publication No. 42-1627), a basic dye (for example,
CIBasic Yello 2 (CI41000) CIBasic Yello 3, C.
I. Basic Red 1 (CI45160), CIBasic Red 9 (CI4250
0), CIBasic Violet 1 (CI42535), CIBasic Viol
et3 (CI42555), CIBasic VIolet 10 (CI45170),
CIBasic Violet 14 (CI42510), CIBasic Blue 1
(CI42025), CIBasic Blue 3 (CI51005), CIBa
sic Blue 5 (CI42140), CIBasic Blue 7 (CI4259
5), CIBasic Blue 9 (CI52015), CIBasic Blue
24 (CI52030), CIBasic Blue 25 (CI52025), CIB
asic Blue 26 (CI44045), CIBasic Green 1 (CI420
40), CIBasicGreen 4 (CI42000), etc.), lake pigments of these basic dyes (CISolvent Black 8 (CI
26150)), benzoylmethyl-hexadecyl ammonium chloride, decyltrimethyl chloride, etc.
Polyamine resins such as quaternary ammonium salts or dialkyltin compounds such as dibutyl or dioctyl, dialkyltin borates, guanidine derivatives, vinyl polymers containing amino groups, condensation polymers containing amino groups, and metal complex salts of monoazo dyes ( For example,
1-20153, JP-B-43-27596, JP-B-44-6397, JP-B-45-264
No. 78), salicylic acid (for example, Japanese Patent Publication No. 55-55)
No. 42752, JP-B-59-7385), metal complexes of dialkylsalicylic acid, naphthoic acid, dicarboxylic acids such as Zn, Al, Co, Cr and Fe, and sulfonated copper phthalocyanine pigments.

Further, a release agent can be internally added to the toner of the present invention in order to prevent offset during fixing. Release agents include natural waxes such as candelilla wax, carnauba wax and rice wax, montan wax, paraffin wax, sasol wax, low molecular weight polyethylene, low molecular weight polypropylene,
Examples include alkyl phosphate esters. These are selected depending on the binder resin and the surface material of the fixing roller. The melting point of these release agents is preferably from 65 to 90 ° C.
When the melting point of the release agent is lower than 65 ° C., blocking tends to occur during storage of the toner. When the melting point of the release agent is higher than 90 ° C., offset occurs in a region where the fixing roller temperature is low. May be easier.

In order to improve fluidity, developability and transferability,
It is also possible to externally add inorganic fine powder to the toner. As the inorganic fine powder, Si, Ti, Al, Mg, Ca, Sr,
Ba, In, Ga, Ni, Mn, W, Fe, Co, Z
Oxides such as n, Cr, Mo, Cu, Ag, V, and Zr, and composite oxides may be used. Among them, fine particles of silicon dioxide (silica), titanium dioxide (titania), and alumina are preferably used. Further, it is effective to perform a surface modification treatment with a hydrophobizing agent or the like. These inorganic fine powders are preferably used in an amount of 0.1 to 2% by weight based on the toner. If the amount is less than 0.1% by weight, the effect of improving toner aggregation is poor. If the amount is more than 2% by weight, problems such as toner scattering between fine lines, contamination in the apparatus, and scratches and abrasion of the photoconductor tend to occur. There is.

The toner of the present invention can be used as either a one-component developer or a two-component developer. When the toner is used as a two-component developer, it is preferable to use the toner mixed with a carrier powder. As the carrier in this case, all known carriers can be used. For example, magnetic particles such as iron powder, ferrite powder, nickel powder, and magnetite powder, or the surface of these magnetic particles is coated with a fluororesin, vinyl resin, or silicone resin Examples thereof include particles treated with a resin or the like, or magnetic particle-dispersed resin particles in which magnetic particles are dispersed in a resin. The average particle size of these magnetic carriers is 35 to
It is preferably 75 μm.

Further, the toner of the present invention contains a magnetic material and can be used as a magnetic toner. When a magnetic toner is used, fine particles of a magnetic substance may be contained in the toner particles. As such a magnetic material, ferrite, including magnetite, iron, nickel, cobalt or other ferromagnetic metals or alloys, or compounds containing these elements, do not contain ferromagnetic elements, but by performing appropriate heat treatment Alloys that exhibit ferromagnetism, for example, manganese-copper aluminum, manganese-copper-tin, and other alloys called Heusler alloys containing manganese and copper, chromium dioxide, and the like can be given. The magnetic material is
It is preferable that it is contained in the form of fine powder having an average particle size of 0.1 to 1 μm, which is uniformly dispersed. The content ratio of the magnetic substance is 10 parts by weight with respect to 100 parts by weight of the obtained toner.
It is preferably from 70 to 70 parts by weight, particularly preferably from 20 to 50 parts by weight.

As an example of a method for producing the toner according to the present invention, first, the above-mentioned dry powder pigment, binder resin, and water are sufficiently mixed by a mixer such as a Henschel mixer, and then a conventional two-roll mill is used. A master batch pigment is obtained by heating and kneading with an open kneader such as a method using a Banbury mixer as an open type in addition to the three rolls or a continuous two roll kneader manufactured by Mitsui Mining Co., Ltd.

Further, the master batch pigment and a binder resin,
When a charge controlling agent and a magnetic toner are used, a magnetic substance and other additives are sufficiently mixed with a mixer such as a Henschel mixer, and then a batch type two-roll, a Banbury mixer or a continuous twin-screw extruder is used. For example, K made by Kobe Steel Ltd.
TK type twin screw extruder, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd., TEX type twin screw extruder manufactured by Nippon Steel Works Co., Ltd., PCM type twin screw extruder manufactured by Ikegai Iron Works, KEX type twin screw extruded by Kurimoto Iron Works Extruder or continuous single-screw kneader, for example, using a hot kneader such as co-kneader manufactured by Buss Company, kneading the constituent materials well,
After cooling, the mixture is roughly pulverized using a hammer mill or the like, further pulverized using a fine pulverizer using a jet stream or a mechanical pulverizer, and then subjected to predetermined classification using a classifier using a swirling stream or a classifier using the Coanda effect. Classify to particle size.

Next, the inorganic fine powder and the toner were sufficiently mixed by a mixer such as a Henschel mixer.
There is a method of obtaining the toner of the present invention by removing coarse particles and aggregated particles by passing through a sieve of 0 mesh or more.

(Examples) Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these. The parts here are based on weight.

Example 1 Pigment: quinacridone-based magenta pigment (CI Pigment Red 122) (saturated water content: 60%): 50 parts Binder resin: polyol resin (Tr = 92 ° C.): 50 parts Auxiliary agent: water ( Electric conductivity: 0.8 μS): 30 parts The above raw materials were mixed with a Henschel mixer to obtain a mixture in which water was permeated into the pigment aggregate. This was kneaded for 45 minutes with two rolls set at a roll surface temperature of 130 ° C. to obtain a master batch pigment (1). The loss on drying was measured to be 0.02% at 110 ° C and 0.00% at 70 ° C.
Met.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: polyol resin: 100 parts Coloring agent: master batch pigment (1): 13 parts Charge control agent: zinc salicylate: 2 parts The above-mentioned raw materials were mixed by a Henschel mixer and melt-kneaded by a twin-screw extruder. This was rolled and cooled, coarsely pulverized by a hammer mill, further finely pulverized by a jet air flow type pulverizer, and finely classified by a wind type classifier to obtain pulverized particles. Further, 1 part of hydrophobic silica was added to the obtained powder, mixed with a Henschel mixer, and then aggregates were removed with an ultrasonic vibrating sieve to obtain a toner. 5 parts of the toner is coated with a silicone resin-coated carrier 95
To prepare a two-component developer. FIG. 1 shows a pigment dispersion state of the master batch pigment (1) used in this example.

The evaluation was carried out by using a transmission electron microscope for the masterbatch pigment in a dispersed state of the pigment, the temperature at which the toner began to flow, and for the toner, the degree of coloring, transparency (haze degree), and charge amount (20 ° C.).
Environment, 40 ° C environment) and running evaluation. Tables 1 and 2 show the evaluation results. In addition, the evaluation method was the method shown below.

<Evaluation of Pigment Dispersion State> A masterbatch pigment was dissolved in THF at a concentration of 10%, an appropriate amount was dropped on a preparation, and covered with a cover glass so that the solvent did not evaporate. Observed and evaluated. Evaluation criteria ◎: no aggregate ○: a little aggregate (no quality problem) △: agglomerate (quality problem) ×: many agglomerates <outflow start temperature> Thereafter, a sample between 100 mesh and 150 mesh was used as a sample by sieving. 1 g of this sample was molded into a predetermined size by a molding machine, and using an elevated flow tester (CFT-500, manufactured by Shimadzu Corporation), a die diameter of 0.5 mm, a pressure of 10 kgf / cm ² , and a heating rate of 3 ° C./min. It measured on condition of. <Color degree> Image density of 1.0m on white paper in single color respectively
The color was fixed under the conditions of g / cm ² and a fixing temperature of 160 ° C., and the degree of coloring was measured with a Macbeth densitometer (RD-514). Note that the higher the numerical value, the higher the degree of coloring. <Transparency (degree of haze)> On an OHP sheet, each image was fixed in a single color under the conditions of image density: 1.0 mg / cm ² , fixing temperature: 150 ° C., and a continuous haze computer manufactured by Suga Test Instruments Co .: H
It was measured by GM-2DP type. In addition, transparency is so favorable that a numerical value is small. <Charge amount> The toner and the carrier are weighed so that the toner concentration becomes 5%, and the toner and the carrier are allowed to stand at a predetermined temperature for 1 hour, and then stirred and mixed under a predetermined environment for 10 minutes. This is 50
It is put into a measuring gauge set with a mesh of 0 mesh, blow-off for 30 seconds, the charge amount Q (μC) and the mass M (g) of the scattered powder are measured, and the charge amount Q / M (μC / g) I do. <Running evaluation> Ricoh Im
After setting the printer to agio color 2800 and running 10K sheets in the single color mode, the degree of toner scattering around the developing unit was evaluated.

Example 2 The same raw materials as in Example 1 were mixed with a Henschel mixer to obtain a mixture in which water was permeated into the pigment aggregate. This was kneaded for 30 minutes with two rolls set at a roll surface temperature of 110 ° C. to obtain a master batch pigment (2). The loss on drying was measured to be 1.00% at 110 ° C and 0.02% at 70 ° C.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: Polyol resin: 100 parts Coloring agent: Master batch pigment (2): 13 parts Charge control agent: Zinc salicylate: 2 parts The above-mentioned raw materials were used as toner in the same manner as in Example 1 to obtain a toner. It was carried out in the same manner as in the evaluation. Tables 1 and 2 show the evaluation results.

Example 3 The same raw materials as in Example 1 were mixed with a Henschel mixer to obtain a mixture in which water was soaked in the pigment aggregate. This was kneaded with two rolls set at a roll surface temperature of 75 ° C. for 60 minutes to obtain a master batch pigment (3). The loss on drying was measured to be 5.00% at 110 ° C and 0.10% at 70 ° C.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: Polyol resin: 100 parts Coloring agent: Master batch pigment (3): 13 parts Charge control agent: Zinc salicylate: 2 parts The above-mentioned raw materials were used as toner in the same manner as in Example 1 to obtain a toner. A similar evaluation was performed. Tables 1 and 2 show the evaluation results.

[0059] The same raw materials as Example 4 Example 1 were mixed by a Henschel mixer to obtain a mixture soaked with water to a pigment aggregate. This was kneaded for 30 minutes with two rolls set at a roll surface temperature of 140 ° C. to obtain a master batch pigment (4). The loss on drying was measured to be 0.01% at 110 ° C and 0.00% at 70 ° C.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: Polyol resin: 100 parts Coloring agent: Master batch pigment (4): 13 parts Charge control agent: Zinc salicylate: 2 parts The above-mentioned raw materials were used as toner in the same manner as in Example 1 to obtain a toner. A similar evaluation was performed. Tables 1 and 2 show the evaluation results.

Example 5 A mixture in which water was soaked in a pigment aggregate was obtained in the same manner as in Example 1 except that water having an electric conductivity of 10 μS was used. This was kneaded for 45 minutes with two rolls set at a roll surface temperature of 110 ° C. to obtain a master batch pigment (5). The loss on drying was measured to be 0.02% at 110 ° C and 0.00% at 70 ° C.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: Polyol resin: 100 parts Coloring agent: Master batch pigment (5): 13 parts Charge control agent: Zinc salicylate: 2 parts The above-mentioned raw materials were used as toner in the same manner as in Example 1 to obtain a toner. A similar evaluation was performed. Tables 1 and 2 show the evaluation results.

Example 6 Pigment: quinacridone-based magenta pigment (CI Pigment Red 122) (saturated water content: 60%): 40 parts Binder resin: polyol resin (Tr = 92 ° C.): 60 parts Auxiliary agent: water ( electrical conductivity: 0.8 .mu.s): 24 parts the above raw materials were mixed in a Henschel mixer to obtain a mixture soaked with water to a pigment aggregate. This was kneaded for 45 minutes with two rolls set at a roll surface temperature of 110 ° C. to obtain a master batch pigment (6). The loss on drying was measured to be 0.02% at 110 ° C and 0.00 at 70 ° C.
% Met.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: polyol resin: 100 parts Coloring agent: master batch pigment (6): 16.3 parts Charge control agent: zinc salicylate: 2 parts The same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results.

Example 7 Pigment: quinacridone-based magenta pigment (CI Pigment Red 122) (saturated water content: 60%): 60 parts Binder resin: polyol resin (Tr = 92 ° C.): 40 parts Auxiliary agent: water ( (Electric conductivity: 0.8 μS): 50 parts The above raw materials were mixed with a Henschel mixer to obtain a mixture in which water was permeated into the pigment aggregate. This was kneaded with two rolls set at a roll surface temperature of 110 ° C. for 45 minutes to obtain a master batch pigment (7). The loss on drying was determined to be 0.50% at 110 ° C and 0.04% at 70 ° C.
% Met.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: Polyol resin: 100 parts Coloring agent: Master batch pigment (7): 10.8 parts Charge control agent: Zinc salicylate: 2 parts The same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results.

Example 8 Pigment: quinacridone-based magenta pigment (CI Pigment Red 122) (saturated water content: 60%): 50 parts Binder resin: polyester resin (Tr = 89 ° C.): 50 parts Auxiliary agent: water ( Electric conductivity: 0.8 μS): 30 parts The above raw materials were treated in the same manner as in Example 1 to obtain a master batch pigment (8). The loss on drying was measured to be 0.02% at 110 ° C and 0.00% at 70 ° C.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: polyester resin: 100 parts Coloring agent: star batch pigment (8): 13 parts Charge control agent: zinc salicylate: 2 parts The above-mentioned raw materials were used as a toner in the same manner as in Example 1 to obtain a toner. A similar evaluation was performed. Tables 1 and 2 show the evaluation results.

Example 9 Pigment: copper phthalocyanine blue pigment (CI Pigment Bluw15) (saturated water content: 40%): 50 parts Binder resin: polyester resin (Tr = 89 ° C.): 50 parts Auxiliary agent: water ( Electric conductivity: 0.8 μS): 25 parts The above raw materials were treated in the same manner as in Example 1 to obtain a master batch pigment (9). The loss on drying was measured to be 0.01% at 110 ° C and 0.00% at 70 ° C.

Next, using this master batch pigment,
A toner was obtained by the following method. Binder resin: polyester resin: 100 parts Coloring agent: masterbatch pigment (9): 6 parts Charge control agent: zinc salicylate: 2 parts The above-mentioned raw materials were used as toner in the same manner as in Example 1 to obtain toner. A similar evaluation was performed. Tables 1 and 2 show the evaluation results.

Example 10 Pigment: copper phthalocyanine blue pigment (CI Pigment Bluw15) (saturated water content: 40%): 50 parts Binder resin: polyester resin (Tr = 89 ° C.): 50 parts Auxiliary agent: water ( (Electric conductivity: 0.8 μS): 15 parts The above raw materials were mixed with a Henschel mixer to obtain a mixture in which water was permeated into the pigment aggregate. This is 3k by 3 rolls set to the first roll surface temperature of 110 ° C.
The kneading was repeated five times for each g to obtain a master batch pigment (10). The loss on drying was measured at 110 ° C.
Was 0.01% and at 70 ° C 0.00%. Next, using this master batch pigment, a method similar to that in Example 9 was used.
The same evaluation as in Example 1 was performed using the toner. Tables 1 and 2 show the evaluation results.

Example 11 A mixture in which water was soaked in a pigment aggregate was obtained in the same manner as in Example 9. Using a continuous two-roll kneader manufactured by Mitsui Mining Co., Ltd., a front roll rotation speed of 75 rpm, a rear roll rotation speed of 50 rpm, an inlet side front roll set temperature of 90 ° C., an outlet side front roll set temperature of 50 ° C.,
Kneading was performed under the conditions of a residence time of 10 minutes to obtain a master batch pigment (11). When this loss on drying was measured, 11
It was 0.02% at 0 ° C and 0.00% at 70 ° C. Next, using this master batch pigment, a toner was produced in the same manner as in Example 9, and the same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results.

Comparative Example 1 The same raw materials as in Example 1 were mixed with a Henschel mixer to obtain a mixture in which water was soaked in the pigment aggregate. This was kneaded for 90 minutes with two rolls set at a roll surface temperature of 130 ° C. to obtain a master batch pigment (12). The loss on drying was measured to be 0.005% at 110 ° C and 0.000% at 70 ° C.
Next, using this master batch pigment, a toner was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results. As shown in the table, this method not only resulted in extremely low productivity, but also caused filming in the running evaluation, making running of 10K sheets or more virtually impossible.

Comparative Example 2 The same raw materials as in Example 1 were mixed with a Henschel mixer to obtain a mixture in which water was permeated into the pigment aggregate. This was kneaded for 10 minutes with two rolls set at a roll surface temperature of 110 ° C. to obtain a master batch pigment (13). The loss on drying was measured to be 5.50% at 110 ° C and 0.05% at 70 ° C.
Next, using this master batch pigment, a toner was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results. FIG. 2 shows a pigment distribution state of the master batch pigment (13) used in this example.

Comparative Example 3 Pigment: quinacridone-based magenta pigment (CI Pigment Red 122): 50 parts Binder resin: polyol resin (Tr = 92 ° C.): 50 parts The above raw materials were mixed with a Henschel mixer to obtain a mixture. Was. This was kneaded for 45 minutes with two rolls set at a roll surface temperature of 130 ° C. to obtain a master batch pigment (14). The loss on drying was measured at 110 ° C.
Was 0.00% and that at 70 ° C. was 0.00%. Next, using this master batch pigment, a toner was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results.

Comparative Example 4 Pigment: quinacridone magenta pigment (CI Pigment Red 122): 50 parts Binder resin: polyol resin (Tr = 92 ° C.): 50 parts Water / acetone (= 50/50): 30 parts The raw materials were mixed with a Henschel mixer to obtain a mixture in which water / acetone was impregnated in the pigment aggregate. This is rolled by two rolls set at a roll surface temperature of 130 ° C.
The mixture was kneaded for 5 minutes to obtain a master batch pigment (15). The loss on drying was measured to be 2.00% at 110 ° C,
At 70 ° C, it was 0.60%. Next, using this master batch pigment, a toner was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Tables 1 and 2 show the evaluation results.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

According to the present invention, the dispersibility of the pigment can be improved without using a low-boiling point organic solvent even in a toner using a pigment-based colorant, so that the transparency, It is possible to achieve both improvement in the degree of coloring and stability.

[Brief description of the drawings]

Masterbatch pigment used in Figure 1 Example 1 (1)
3 is an optical micrograph showing the state of pigment dispersion.

FIG. 2 shows the masterbatch pigment (1) used in Comparative Example 2.
It is an optical microscope photograph showing the pigment dispersion state of 3).

Claims (20)

[Claims] 1. A method for producing a toner using a masterbatch kneading method in which a pigment is dispersed in a resin, wherein a dry powder pigment is used as the pigment, and water is mixed when the dry powder pigment and the binder resin are mixed. Of the toner obtained by heating and kneading the mixture obtained by adding
Loss on drying at 110 ° C is 0.01-5.0% and 70 ° C
A method for producing a toner, comprising: kneading the mixture so that the loss on drying is 0.5% or less. 2. The method according to claim 1, wherein the kneading is performed such that the loss on drying at 110 ° C. is 0.01 to 1.0% and the loss on drying at 70 ° C. is 0.05% or less. 3. A master batch kneading step in which a raw material mixture containing at least a binder resin, a pigment and water is kneaded, and the kneaded product obtained in the master batch kneading step is adjusted so that the toner has a desired pigment concentration. A dilution kneading step of diluting with the same kind or different kind of binder resin, and a method of producing a color toner by pulverizing the kneaded material obtained in the dilution kneading step, which is used in the master batch kneading step A toner obtained by using a dry powder pigment as a pigment, heating and kneading a mixture obtained by adding water when mixing the dry powder pigment and the binder resin, and removing water added at the time of mixing. Of 110 after kneading
A method for producing a toner, comprising kneading so that the loss on drying at a temperature of 70 ° C is 0.01 to 5.0% and the loss on drying at a temperature of 70 ° C is 0.5% or less. 4. The method according to claim 3, wherein the kneading is performed so that the loss on drying at 110 ° C. is 0.01 to 1.0% and the loss on drying at 70 ° C. is 0.05% or less. 5. The method according to claim 3, wherein the pigment content in the master batch pigment kneading step is 40 to 60% by weight. 6. The method according to claim 3, wherein in the master batch pigment kneading step, the amount of water added during mixing is 10 to 50% by weight. 7. The method according to claim 3, wherein water having an electric conductivity of 1.0 μS or less is used in the master batch pigment kneading step. 8. The method according to claim 3, wherein in the master batch pigment kneading step, a pigment having a saturated water supply rate of 20 to 100% is used. 9. The method according to claim 3, wherein a polyol resin is used as the binder resin in the master batch pigment kneading step. 10. The method according to claim 3, wherein a polyester resin is used as the binder resin in the master batch pigment kneading step. 11. The method according to claim 3, wherein an open type kneader is used as the kneader used in the master batch pigment kneading step. 12. The method according to claim 11, wherein the set temperature (T) of the kneader is a temperature condition satisfying the following equation between the set temperature (Tr) and the outflow start temperature (Tr) of the binder resin. Manufacturing method of toner. 80 <Tr <110 (° C) Tr-20 <T <Tr + 50 (° C) 13. The kneading method according to claim 1, wherein the outflow starting temperature (Tm) after kneading the master batch and the outflow starting temperature (Tr) of the binder resin satisfy the following expression. 13. The method for producing a toner according to any one of items 12 to 12. 80 <Tr <110 (° C) Tm> Tr + 20 (° C) 14. A loss on drying at 110 ° C. of 0.01 to 5.0.
%, And a loss on drying at 70 ° C. of 0.5% or less. 15. A loss on drying at 110 ° C. of 0.01 to 1.0.
%, And a loss on drying at 70 ° C. of 0.05% or less. 16. A masterbatch pigment obtained by the method for producing a toner according to claim 1. 17. Using the master batch pigment according to claim 14, diluting and kneading with the same or different binder resin so as to obtain a desired pigment concentration of the toner,
A color toner obtained by pulverizing the obtained kneaded material. 18. has a dilution kneading step of diluting with claim either allogeneic so the master batch pigment to a desired pigment concentration of toner according to claim 14 to 16 or heterologous binder resin, the dilution A method for producing a color toner, comprising pulverizing a kneaded product obtained in a kneading step. 19. An image forming method using the color toner according to claim 17. 20. An image forming apparatus using the color toner according to claim 17.