JPH11190914A - Full-color electrophotographic toner and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner in which the electrification rising characteristics and the dispersion state of a coloring agent and a release agent are improved. SOLUTION: In this toner, the dispersion diameter of the coloring agent in the binder resin is <=1 μm and the dispersion diameter of the release agent is between 0.1 μm and 2 μm. The toner shows >=70% electrification rising rate calculated as Z(%)=(Q20 /Q600 )×100, wherein Q20 is the charge amt. obtd. by mixing the toner with a carrier for 20 sec under conditions of normal temp., normal humidity and 5% toner density, and Q600 is the charge amt. obtd. by mixing for 10 min under the same conditions as described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in an image forming method for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, and the like. Providing a manufacturing method that dramatically improves the dispersion state of the release agent and the charge rising characteristics, and has excellent light transmittance at a high degree of coloration even at a low colorant concentration, without toner scattering,
The present invention relates to a full-color electrophotographic toner capable of obtaining a stable image excellent in color tone reproducibility and offset resistance also in image quality, and a method for producing the same.

[0002]

2. Description of the Related Art In general, toner is used to develop an electrostatic latent image formed on a latent image carrier in an image forming method such as electrophotography and electrostatic photography. The toner is required to be fine particles, have excellent fluidity, and be appropriately charged powder. As a method for developing an electrostatic latent image, a method using a two-component developer which is a mixture of a toner and a carrier and a method using a one-component developer not containing a carrier are known. In the former developing method using a two-component developer, relatively stable and good images can be obtained, but the carrier deterioration and the mixing ratio of the toner and the carrier are apt to fluctuate. In general, an image is obtained by developing an electrostatic latent image with a toner on a photoreceptor, transferring the image to a transfer sheet or the like, and fixing the image. As a fixing method at this time, a hot roll fixing method in which pressure is applied by heating with a heated roll is generally used. This method has a high thermal efficiency and can quickly fix the toner image. On the other hand, a so-called offset phenomenon in which a part of the toner image adheres to the roll surface and transfers to the sheet again tends to occur.

Some proposals have been made for such conventional problems. For example, JP-A-2-23506
Japanese Patent Application Laid-Open No. 7-212139 proposes a method in which a release agent is internally added at an appropriate ratio inside the toner particles, and a release agent is externally added at an appropriate ratio to the surface of the toner particles. In this method, it is possible to impart a releasing property to the toner. However, since the releasing agent is externally added to the toner surface, the fluidity and the preservability are markedly inferior and have a uniform charge amount distribution. Since it becomes difficult to obtain a developer, a problem also occurs in image quality. Further, JP-A-3-168649 specifies that the dispersion diameter of the low molecular weight wax in the binder resin is 1 μm or less, but in order to obtain a desired dispersion diameter, kneading is carried out for a long time with a large shearing force. A method has been proposed. This method aims at suppressing the offset phenomenon by defining the dispersion diameter of the release agent, but the production equipment that can be used is limited because a large shear force is required, and the kneading time is also extremely large. This is very disadvantageous in terms of productivity due to the lengthening.

In recent years, colorization of the electrophotographic system has been advanced, and demands for high image quality and high reproducibility have been increasing. As the full-color electrophotographic toner, toner colored yellow, magenta, and cyan is used. Also, a black toner is used if necessary. In such a color toner, it is essential that the fixed toner has good spectral reflection characteristics without irregular reflection and that the superimposed toner has transparency in order to reproduce all colors. It is indispensable to improve the dispersion of the colorant in the binder resin. Further, in order to obtain high resolution and sharpness of an image, it is desirable that the particle size of the toner is also small. In general, a toner is prepared by melting and kneading predetermined materials such as a binder resin, a colorant (a dye, a pigment, a magnetic substance, etc.), a charge controlling agent, etc., cooling and solidifying, and then pulverizing. It is obtained by adding an additive (ultrafine colloidal silica or the like) in order to impart fluidity to the obtained fine particle powder, and mixing with stirring. In the conventional melt kneading method, a screw-type extrusion continuous kneader, a two-roll mill, a three-roll mill, a pressurized heating kneader and the like are used.

[0005] The dispersion state of the colorant in the binder resin depends on this kneading step. If the dispersion of the colorant is insufficient, the degree of coloration of the obtained color toner is low, and the color is not vivid.
Due to lack of transparency, color reproducibility is remarkably poor. In the general melt-kneading method as described above, the dispersion of the colorant in the binder resin is at an insufficient level, and it is difficult to obtain good image quality. The so-called master batch method has been proposed to solve such a conventional problem.

For example, in Japanese Patent Application Laid-Open No. 3-155568, a solvent is added to a part of a binder resin and a dye / pigment, and the mixture is melt-kneaded in advance. And a method of melt-kneading the obtained masterbatch with the obtained masterbatch. In this method, the dispersibility of the dye / pigment in the binder resin is improved by adding a solvent.However, since the kneading temperature at the time of obtaining a master batch is high, the viscosity of the kneaded material is reduced, and Dispersion is not significantly improved, and there is a disadvantage that it takes an enormous amount of time to obtain a desired dispersion level. Further, Japanese Patent Application Laid-Open No. 8-123076 proposes a method in which a mixture of a binder resin, a charge control agent and a colorant is kneaded with an organic solvent in advance at a temperature lower than the melting temperature of the binder resin in the first stage. However, it is effective in improving the dispersibility of the charge control agent and the colorant, and very good quality can be obtained in a system containing no release agent. However, in a system containing a release agent, the dispersibility of the release agent also greatly contributes to the quality, and thus the method is insufficient. In addition, kneading for obtaining the master batch is a batch process, so there is a concern that productivity may be reduced.

In the above-mentioned general method for producing a toner, for example, in the case of collision-type pulverization, the shape of the obtained particles is irregular, and an additive is added to the powder particles in order to maintain fluidity. Is added and the mixture is stirred and mixed. The toner obtained by this method has a drawback that the apparent index such as fluidity is improved, but the characteristics of the toner base itself are not changed. Some suggestions have been made. For example, in Japanese Patent Publication No. 7-181732,
A method has been proposed in which pulverized toner base particles are subjected to spheroidizing treatment by mechanical impact force.In this method, spheroidizing treatment is performed until there is no unevenness on the toner surface. In the system, if the spherical treatment is performed to this level, the release agent is melted and the desired quality cannot be obtained.

Japanese Patent Publication No. Hei 7-181736 proposes a method in which a pulverized raw material is pulverized by an impinging airflow pulverizing means and then subjected to surface modification using a low impact treatment apparatus. A crypton system without classifier is used for efficiency. However, the surface modification of the toner obtained by this method is not satisfactory, and an ideal charge rising property cannot be obtained.

In the above proposals, there are problems such as side effects and a decrease in productivity due to the addition of a release agent, and in the proposals as well, there are problems such as a decrease in productivity due to a high dispersion of the pigment, so that a totally satisfactory product is obtained. Not been. Furthermore, no proposal has been made to simultaneously disperse the colorant and the release agent at a high level. Further, in the proposal, the desired powder and charging characteristics cannot be obtained in a system containing a release agent, and it is necessary to consider the dispersion diameter of the release agent.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and the first object of the present invention is to provide a colorant having a high degree of coloration even at a low colorant concentration and having excellent light transmittance. To provide a full-color electrophotographic toner capable of obtaining a stable image with high image density, excellent color reproducibility and excellent anti-offset properties at high image quality, and further excellent in charge start-up characteristics and without toner scattering. And a method for producing the toner. The second object of the present invention can be used as a two-component developing toner,
In particular, it is an object of the present invention to provide a full-color electrophotographic toner useful as a one-component toner.

[0011]

Means for Solving the Problems The present inventors have continued to study to solve the above-mentioned conventional problems, and as a result, the dispersion of the colorant and the release agent in the binder resin has been greatly increased. The method of improving the performance, that is, by pre-melting and kneading a mixture consisting only of the binder resin, the colorant, and the release agent, the release agent is also dramatically dispersed in the binder resin in accordance with the dispersion of the colorant. A master batch is obtained. At the time of the kneading, a large shearing force which has been conventionally required is unnecessary, and a continuous kneader which was not suitable for performing the conventional masterbatch kneading can be used, which is very advantageous from the viewpoint of production efficiency. The binder resin and the charge control agent were added to the masterbatch, melt-kneaded, cooled and solidified, and subjected to primary pulverization with a jet pulverizer having compressed air and a collision plate as main components. Thereafter, a rotor type pulverizer having a fixed container as an outer wall and a rotary piece having the same central axis as the fixed container as a main component is connected to an airflow classification device, and the airflow classification means performs classification. As a result, the fine powder is circulated through the rotor type pulverizer and the airflow classifier to perform secondary pulverization, so that a good level of fluidity and storage stability can be obtained without melting the release agent. It is very easy and efficient to manufacture full-color electrophotographic toner with excellent charge rise characteristics, no toner scattering, and excellent color reproducibility, releasability, and offset resistance. It was found that improving effect is remarkable,
Based on these, the present invention has been completed.

That is, according to the present invention, (1) a toner used in an image forming method for developing an electrostatic latent image in electrophotography, electrostatic recording, electrostatic printing, etc., wherein at least a binder resin and In a toner for electrophotography mainly containing an agent, a release agent, and a charge control agent, the dispersion diameter of the pigment in the binder resin is 1 μm or less, and the dispersion diameter of the release agent is 0.1 μm or more and 2 μm or less. The charge amount Q ₆₀₀ obtained when stirring and mixing with a carrier for 10 minutes under the condition of a toner concentration of 5% under humidity.
Respect, when the charge amount obtained when mixed with stirring for 20 seconds under the same conditions and _{Q 20, Z (%) =} (Q 20 / Q 600) charge rising ratio 70 calculated by × 100 (%) The present invention provides a full-color electrophotographic toner characterized by the above. Here, the charge amount (Q / M) is a value measured using a so-called suction type Faraday gauge method in which the toner on the toner carrier is collected in a Faraday gauge by air. Specifically, a means called a blow-off method is employed.

Further, according to the present invention, (2) when the softening temperature of the binder resin is T _sr and the outflow start temperature of the binder resin is T _{fr in the} above (1), the melting point M _pw of the release agent is T _sr +5 <
For full-color electrophotographic toner is provided which lies in the range of _{M pw <T fr -5 (℃} ). Further, in (1) and (2), a toner for full-color electrophotography is provided, wherein the release agent is an ester release agent. Further, according to the present invention, the above (1) and (2)
Wherein the release agent is carnauba wax.

Further, according to the present invention, there is provided a full-color electrophotographic toner characterized in that in (1) and (2), the volume average particle diameter is 9 μm or less. In (1) and (2), the content of fine powder of 5 μm or less is 20%.
Provided is a toner for full-color electrophotography, which is not more than a few percent. Further, there is provided a toner for full-color electrophotography, wherein the degree of aggregation is 4 to 20% or less in (1) and (2).

Further, according to the present invention, (3) a first-stage melt-kneading of a mixture consisting only of a binder resin, a colorant and a release agent, and cooling and crushing the obtained kneaded material, The present invention provides a method for producing a full-color electrophotographic toner, characterized by adding a binder resin and a charge controlling agent to a product and performing a second-stage melt-kneading. According to the present invention, in 100 parts by weight of the first-stage kneaded product in the above (3), the colorant is 10 to 4 parts by weight.
A method for producing a full-color electrophotographic toner is provided, wherein 0 parts by weight and a release agent are contained in the range of 10 to 50 parts by weight and the first stage of melt-kneading is performed.

Further, according to the present invention, after the primary pulverization of the pulverized raw material is performed by a jet pulverizer having compressed air and a collision plate as main components, a fixed container as an outer wall and the fixed container A rotor type pulverizer having, as a main component, a rotary piece having the same central axis as a rotary piece is connected to an airflow classification device, and the fine powder is classified by the airflow classification means so that the fine powder is removed by the rotor type pulverization. The present invention provides a method for producing a full-color electrophotographic toner, wherein the secondary pulverization is performed by circulating the toner through an apparatus and the airflow classifier.

According to the inventor's intensive studies, it has been found that when the dispersion of the colorant in the binder resin is insufficient,
The degree of coloring of the obtained toner is low, and the transparency is inferior. In particular, in the case of a color toner, yellow, magenta, and cyan are superimposed to reproduce a color tone. The reproducibility of the color tone is significantly reduced. Also, it was found that when the dispersion of the release agent was insufficient, a developer having poor fluidity and storage stability and having a uniform charge amount distribution could not be obtained, causing deterioration in image quality. Further, when the release agent is extremely dispersed, the releasability of the toner is reduced, and the sheet is wrapped around the fixing roller and a problem of a nail mark is generated. Further, when the charge rising ratio of the toner is low, it causes toner scattering, image density reduction, and background contamination, and also extremely deteriorates color tone reproducibility. For this purpose, the dispersion diameter of the degree of coloring in the binder resin must be 1 μm or less, the dispersion diameter of the release agent must be 0.1 μm or more and 2 μm or less, and the charging rise ratio (Z) must be 70% or more. It was revealed. Furthermore, by performing a ternary master batch kneading composed of only a binder resin, a colorant, and a release agent as a production method, a good colorant,
The level of the dispersion diameter of the release agent is obtained, and after the primary pulverization of the pulverized raw material is performed by a jet pulverizer having compressed air and a collision plate as main components, a fixed container as an outer wall is provided. A rotor type pulverizer having, as a main component, the fixed container and a rotary piece having the same central axis is connected to an airflow classification device, and the fine powder is classified by the airflow classification means. It was found that good secondary charging characteristics could be obtained by circulating the rotor-type pulverizer and the airflow classifier to perform secondary pulverization.

In the kneading of the masterbatch of the present invention, the softening temperature of the binder resin is T _sr , the outflow start temperature of the binder resin is T _fr , When the melting point is M _pw , T _sr +5 <M _pw <T _fr −
It is desirable to satisfy the relationship of 5 (° C.). When the melting point M _pw of the release agent is lower than T _sr +5 (° C.), the release agent tends to melt prior to the binder resin at the time of kneading, and the release agent is liquefied and separated from the kneaded material to form a colorant. It does not function as an improvement in dispersibility, and it is difficult to disperse the release agent itself in the binder resin. When the melting point M _pw of the release agent is higher than T _fr −5 (° C.), the binder resin tends to melt before the release agent,
In this case, although it functions to improve the dispersibility of the colorant,
The viscosity of the binder resin is too low, which is disadvantageous in dispersing the release agent. That is, the melting point M _pw of the release agent is T _sr
It is desirable to be in the range of +5 <M _pw <T _fr -5 (° C.). Further, the binder resin and the release agent are used alone or in combination of two or more, but when two or more are used,
T _sr for any combination of binder resin and release agent
It is necessary to satisfy the relationship of +5 <M _pw <T _fr −5 (° C.).

Further, as the release agent used in the present invention, those having a melting point Mpw within the above range may be any of synthetic wax, natural wax and the like, but are not compatible with the binder resin. Wax molecular weight distribution Mw / Mn is 1.0
It is preferable that the number is 1.2. Among them, ester waxes having an ester bond, candelilla wax,
It is preferable to use natural wax such as carnauba wax and rice wax, montan wax and the like. Further, among ester waxes, it is very preferable to use carnauba wax. In the present invention, when carnauba wax is used, it is evident that, even at a low shear force during the first-stage melt-kneading, it is easily dispersed while being incompatible with the binder resin, and particularly the offset resistance is improved. became.

In the present invention, it is desirable that the volume average particle diameter is 9 μm or less. It is indispensable to reduce the particle diameter of the toner in order to improve the resolution. Fluidity and preservation tend to deteriorate. However, the high dispersion of the release agent is achieved by the ternary master batch kneading of the present invention, and the surface treatment is performed by a rotor type pulverizer.
Even when the volume average particle size is 9 μm or less, a good level of fluidity and storage stability can be obtained, and resolution can be improved, and a high-quality image can be obtained. Also, when the content of the fine powder having a particle size of 5 μm or less is set to 20% or less, the effect of improving the quality in terms of fluidity and storability is remarkable. Good levels are obtained.

Further, the ternary masterbatch kneading of the present invention and the surface treatment by a rotor type pulverizer are carried out to obtain a cohesion degree of 4 to 4 irrespective of the formulation containing the release agent.
It has been found that when a good level of 20% is obtained, good levels of fluidity, replenishability, storability, and toner charging rise characteristics are obtained. In the present invention, the higher the content ratio of the release agent and the colorant during kneading the master batch, the more the quality tends to be improved. However, when the colorant exceeds 40 parts by weight with respect to 100 parts by weight of the master batch kneading, kneading stability is lacking and production becomes difficult.
If the release agent also exceeds 50 parts by weight, the kneaded material becomes brittle,
Dispersion in the binder resin also becomes difficult, and the resulting toner does not have sufficient quality in terms of fluidity and storage stability. If both the colorant and the release agent are less than 10 parts by weight, the desired dispersion will be obtained. In order to obtain a state, a large shearing force is required, and a decrease in productivity is inevitable.

The dispersion diameter of the release agent and the colorant in the binder resin can be measured by various methods, and the one obtained by rolling and cooling after kneading is a microtome MT-6000 (manufactured by RMC Inc.).
, Sliced to a thickness of 1000 mm, observed with a transmission electron microscope JSM-880 (manufactured by JEOL Ltd.), and further measured the particle size by an image analyzer LUZEX500 (manufactured by Nireco) via a scanning converter unit. .

Although the particle size distribution of the toner can be measured by various methods, in the present invention, the measurement was carried out by using a small pore transmission method (a Coulter counter method). A Coulter Counter TAII (manufactured by Coulter) was used as a measuring device, and 1
% Saline and the aperture as 100 μm. The softening temperature and the outflow start temperature of the binder resin were measured using an elevated flow tester (CFT-500) (manufactured by Shimadzu Corporation), the diameter of the pores of the die was 1 mm, the pressure was 20 kg / cm ² ,
The measurement was carried out at a heating rate of 6 ° C./min. The melting point of the wax was measured as follows. Rig from Rigaku Denki
The measurement was carried out with an aku THERMOFLEX TG8110 model under the condition of a temperature rising rate of 10 ° C./min, and the main peak of the endothermic curve was defined as the melting point.

As the measurement of the main density and the haze degree, first, an image of a fixed area in which the toner adhesion amount is changed is developed,
Transfer to paper. After fixing the paper, a colorimeter X-
The main concentration was measured using rite. By this measurement, the amount of adhesion at a main concentration of 1.5 was converted, and the obtained amount of adhesion was converted to O.
After the image was transferred to an HP sheet and further fixed, the haze was measured using a fully automatic haze computer HGM-2DP.

The toner of the present invention comprises at least a binder resin, a colorant, a release agent and a charge control agent. As the binder resin used in the toner of the present invention, all of those conventionally used as binder resins for toner are applied. Specifically, a homopolymer of styrene such as polystyrene, polychlorostyrene, polyvinyltoluene and a substituted product thereof; styrene / p-chlorostyrene copolymer, styrene / propylene copolymer, styrene / vinyltoluene copolymer, styrene / Vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer Copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / acrylonitrile copolymer, styrene /
Vinyl ethyl ether copolymer, styrene / vinyl methyl ketone copolymer, styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / acrylonitrile / indene copolymer, styrene / maleic acid copolymer, styrene / maleic Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate,
Polyethylene, polypropylene, polyester, polyvinyl butyl butyral, polyacrylic acid resin, rosin,
Modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc., are used alone or as a mixture of two or more. You.

As the colorant used in the toner of the present invention, all pigments and dyes conventionally used as colorants for toner are applied. Specifically, nigrosine dye, aniline blue, calco oil blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, phthalocyanine green,
Hansa Yellow G rhodamine 6C lake, chrome yellow, quinacridone, benzidine yellow, malachite green, malachite green hexalate, rose bengal, monoazo dyes, disazo dyes, trisazo dyes and the like.

Examples of the charge control agent used in the toner of the present invention include a nigrosine dye, a quaternary ammonium salt, a polymer having an amino group, a metal-containing azo dye, a complex compound of salicylic acid, and a phenol compound.
Further, in the toner of the present invention, in order to impart releasability, in addition to synthetic waxes such as low molecular weight polyethylene and polypropylene, candelilla wax, carnauba wax, rice wax, wood wax, jojoba oil and the like. Vegetable waxes; Animal waxes such as beeswax, lanolin, and spermaceti; Mineral waxes such as montan wax and ozokerite; Oils and fats such as hardened castor oil, hydroxystearic acid, fatty acid amides, and phenol fatty acid esters These may be used alone or in combination of two or more.

In the present invention, the release agent is not particularly limited, but contains a release agent having a melting point in the range of 70 to 120 ° C., preferably a release agent in the range of 80 to 110 ° C. It is desirable to contain. When only a release agent having a melting point lower than 70 ° C. is contained, an offset phenomenon is likely to occur during fixing by a hot roll fixing method. Also, in a toner containing only a releasing agent having a melting point higher than 120 ° C., a desired releasing effect is hardly obtained, and it is necessary to increase a fixing temperature in order to obtain a releasing effect, and to avoid an increase in power consumption. I can't.

Further, in addition to the above-mentioned releasing agent, various plasticizers (dibutyl phthalate, phthalate, etc.) may be added to the toner used in the present invention in order to adjust the thermal, electrical and physical properties of the toner as required. It is also possible to add auxiliary agents such as dioctyl acid) and a resistance adjusting agent (such as tin oxide, lead oxide, and antimony oxide). Further, additives other than the above-mentioned releasing agents, auxiliaries, and the like can be added to the toner of the present invention, if necessary. Examples of the additives include fluidity imparting agents such as colloidal silica, titanium oxide, and aluminum oxide. The flow imparting agent preferably has a particle diameter of primary particles smaller than 0.1 μm, and has a surface subjected to a hydrophobic treatment with a silane coupling agent or silicone oil to have a degree of hydrophobicity of 40 or more.

In the toner production method of the present invention, a binder resin, a charge controlling agent and the like are added to the kneaded material obtained by kneading the ternary master batch in an appropriate ratio, and the mixture is kneaded with a screw type extrusion kneader. Kneading is performed by using a mill, a two-roll mill, a three-roll mill, and a pressure and heating kneader. After the kneaded material is cooled and solidified, it is roughly pulverized using a pulverizer such as a hammer mill. Further, after crushing with a jet mill crusher, surface treatment is performed using a rotor crusher or the like connected to an airflow classifier or the like.For example, as a collision crusher, a hammer mill, a ball mill, a tube mill, a vibration mill, etc. As a jet-type pulverizer having compressed air and a collision plate as main components, one type and an IDS-type collision-type pulverizer (manufactured by Nippon Pneumatic) can be preferably used. Examples of the rotor pulverizer include a roll mill, a pin mill, a fluidized-bed jet mill, and the like. In particular, a fixed container as an outer wall and a rotary piece having the same central axis as the fixed container are provided as main components. Turbo mill (manufactured by Turbo Industries, Ltd.), Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.), fine mill (manufactured by Nippon Pneumatic Industries, Ltd.), etc. can be used as the rotor-type pulverizer. A John separator (DS) classifier (manufactured by Nippon Pneumatic Industries Ltd.), a multi-segment classifier (Elbow Jet; manufactured by Nippon Steel Mining Co., Ltd.) and the like can be used. Furthermore, fine particles are classified using an airflow classifier or a mechanical classifier to obtain fine particles. If necessary, a fluidity imparting agent may be added to and mixed with the fine particles.

Next, the technical contents of the toner of the present invention will be described. The toner of the present invention can be produced by kneading a master batch of a ternary mixture consisting only of a binder resin, a colorant, and a release agent. In this case, the release agent serves as a colorant dispersion aid. The function is also based on the finding that the dispersion of the colorant in the binder resin is dramatically improved. The fact that the release agent functions as a dispersing aid is considered to be due to the oil absorbing property of the colorant,
It is considered that when the coloring agent sucks in the molten release agent, the aggregates are rapidly disintegrated, and high dispersion in the binder resin is possible even with a low shear force. Conventionally, a large shear force and an enormous amount of time were indispensable for masterbatch kneading.However, since a roll mill was used, batch processing had to be performed, leading to a decrease in productivity. Screw-type extrusion continuous kneading, which was not suitable for master batch kneading, because high dispersion was possible even with low shear force, and a toner with high coloring degree and excellent light transmittance was obtained even at low colorant concentration. Can also be used, so that productivity can be improved.

Further, after the system using the master batch kneaded material obtained by the above method is subjected to pulverizing treatment with a jet pulverizer or the like, and then subjected to spherical treatment using a rotor pulverizer or the like, the quality in terms of fluidity and cohesion is improved. An improvement tendency is recognized, and both charging start-up characteristics and releasability are achieved.
For example, in a system using the master batch kneaded material, when the spherical treatment is not performed, the obtained full-color toner has a very good level of transparency and coloring degree, but has an insufficient level of charge rising characteristics. And toner scattering is likely to occur. Further, the release agent dispersion diameter is 2.0 μm.
In the case of a system using the above-mentioned master batch kneaded material, the tendency of the release agent to melt on the toner surface is recognized, and good levels of fluidity and agglomeration degree cannot be obtained. I can't get it. Therefore, by performing the surface treatment of the present invention on the powder particles of the system using the master batch kneaded product having good dispersibility for both the release agent and the colorant by ternary master batch kneading, very good quality can be obtained. Is obtained. The method of the present invention is clearly different from the proposal of JP-B-8-20762 in which the surface is modified in a short time. In the present invention, an airflow classifier is indispensable, and the powder particles are pulverized by a rotor. It is necessary to perform a surface treatment within a range in which the release agent does not melt, particularly in a system containing the release agent, by circulating between the device and the airflow classifier.

In addition, a system containing no release agent, a binder resin,
It is well known that a master batch kneaded with only a colorant requires a large shearing force for highly dispersing the colorant, but the masterbatch obtained by the kneading is further kneaded by adding a release agent. Even though the toner containing no release agent has a slight quality improvement effect on the degree of coloration and haze, a ternary masterbatch consisting of a binder resin, a colorant, and a release agent is kneaded. It does not reach the quality obtained.

A factor controlling the degree of the spherical treatment in the present invention is the residence time in the rotor type pulverizer. For example, in a kryptron system without a classifier, the pulverized particles are sent to the next step without the jet pulverized product staying in the rotor pulverizer. The particle shape does not change at all from the jet pulverized product, and the level difference in the fluidity and the cohesion degree is extremely small. Further, when the residence time in the rotor-type pulverizer is too long, that is, when the amount of the particles returned from the classifier to the pulverizer is increased,
Although the spheroidization proceeds, if the spheroidization proceeds too much, the release agent begins to melt, a phenomenon of a decrease in fluidity is observed, and the desired charge rising characteristics cannot be obtained. Therefore, by performing the spherical treatment to a level at which the release agent does not melt, it is possible to obtain a good charge rising ratio.

The classifier that can be connected to the rotor type pulverizer includes an air flow type and a mechanical type classifier.
In the production method of the present invention, it is preferable to use an airflow classifier. Especially the dispersion separator (DS)
It is preferable to use a type airflow classifier (manufactured by Nippon Pneumatic Industries, Ltd.). This is because the powder particles containing the release agent are classified very efficiently by the swirling airflow supplied into the classification chamber, and the dispersion of the powder particles is not sufficient in the multi-divided classifier utilizing the Coanda effect. This has the disadvantage of being disadvantageous in classification accuracy because it is not done.
In addition, compared to mechanical classifiers and air classifiers, the classification accuracy is inferior, the particle size adjustment is very difficult due to few adjustment factors when changing conditions, and the maintenance such as switching work is also very complicated. There's a problem.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The parts here are based on weight.

Example 1 Binder resin Polyester-based polymer (T _sr = 75 ° C., T _fr = 110 ° C.) 10.0 parts Release agent Low molecular weight polypropylene (M _pw = 85 ° C.) 8.0 parts Colorant C . I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the polyester polymer and 5.0 parts of a salicylic acid compound as a charge control agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle size of 12 μm,
Furthermore, surface treatment was performed using a turbo mill connected to a DS type airflow classifier, and the result was an average particle diameter of 11.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17
Was replaced by 3.5 parts of a rhodamine pigment to obtain a magenta toner having a volume average particle diameter of 12 μm. Further, C.I.
I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Example 2 (when the melting point M _pw of the release agent is higher than T _fr -5 (° C.)) Binder resin Polyester polymer (T _sr = 75 ° C., T _fr = 110 ° C.) 10.0 parts Release agent Low molecular weight polypropylene (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the polyester polymer and 5.0 parts of a salicylic acid compound as a charge controlling agent are added, and a very strong shearing force is applied using a two-roll mill for one hour in a batch process. Kneading was performed. The kneaded material was finely pulverized with a jet mill pulverizer so as to have an average particle diameter of 12 μm, and further subjected to a surface treatment using a turbo mill connected to a DS type airflow classifier, but the average particle diameter was 11.5 μm. Was. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17 was replaced by 3.5 parts of a rhodamine pigment, and the volume average particle size was 1
A 2 μm magenta toner was obtained. Further, C.I. I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Example 3 (when the melting point M _pw of the release agent is lower than T _sr +5 (° C.) and the colorant is 10 parts by weight or less in the master batch kneading process) Binder resin Polyester polymer (T _sr = 75 ° C., T _fr = 110 ° C.) 10.0 parts Release agent Low molecular weight polypropylene (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a biaxial kneader. Although the release agent was slightly melted and separated, kneading was possible. After cooling and solidification, the mixture was roughly pulverized with a hammer mill. 53.5 parts of the polyester-based polymer and 5.0 parts of a salicylic acid-based compound as a charge controlling agent were added to the obtained pulverized product.
Using this roll, kneading was performed for 1 hour in a batch process by applying a very strong shearing force. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle size of 12 μm.
Surface treatment was performed using a turbo mill connected to an S type airflow classifier, and the average particle size was 11.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. Hydrophobic silica is added to 100 parts of the fine particles.
Five parts were added and mixed to obtain a yellow electrophotographic toner. Next, the coloring agent C.I. I. Magenta toner having a volume average particle size of 12 μm was obtained by using 3.5 parts of a rhodamine pigment instead of Pigment Yellow 17. Further, C.I. I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Example 4 (volume average particle size 8 μm with respect to Example 1) The same kneaded material as in Example 1 was finely pulverized by a jet mill pulverizer so as to have an average particle size of 8 μm, and further a DS type air flow type was used. Surface treatment was performed using a turbo mill connected to a classifier, but the average particle size was 7.5 μm. The toner was further classified to obtain yellow, magenta, and cyan toners having a volume average particle diameter of 8 μm (5 μm or less fine powder content: 25%) (0.5 parts of hydrophobic silica was added).

Example 5 (Compared to Example 1, both the colorant and the release agent are 10 parts by weight or less in a master batch kneading formulation) Binder resin Polyester polymer (T _sr = 75 ° C., T _fr = 110) C) 40.0 parts Release agent Low molecular weight polypropylene (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was mixed and kneaded in a batch process using two rolls for 2 hours, solidified by cooling, and coarsely ground by a hammer mill. The polyester-based polymer 4
3.5 parts, salicylic acid compound 5.0 as charge control agent
And melt kneading was performed using a twin-screw kneader. The kneaded material was finely pulverized with a jet mill pulverizer so as to have an average particle diameter of 12 μm, and further subjected to a surface treatment using a turbo mill connected to a DS type airflow classifier, but the average particle diameter was 11.5 μm. Was. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Magenta toner having a volume average particle size of 12 μm was obtained by using 3.5 parts of a rhodamine pigment instead of Pigment Yellow 17. Further, C.I. I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Example 6 (Change of binder resin and release agent from Example 4) Binder resin Polyol resin (T _sr = 72 ° C., T _fr = 98 ° C.) 10.0 parts Release agent Carnauba wax (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the above polyol resin and 5.0 parts of a salicylic acid-based compound as a charge controlling agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle diameter of 8 μm.
Surface treatment was performed using a turbo mill connected to an S-type airflow classifier, but the average particle size was 7.5 μm. The powder was further classified to obtain fine particles having a volume average particle size of 8 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17 was replaced by 3.5 parts of a rhodamine pigment, and the volume average particle size was 8%.
μm magenta toner was obtained. Further, C.I. I. A cyan toner having a volume average particle diameter of 8 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17. In addition, each toner was adjusted so that the content of fine powder of 5 μm or less was 25%.

Example 7 (Compared to Example 6, volume average particle diameter 8 μm and 5 μm or less, fine powder content 15%) The same kneaded material as in Example 1 was finely milled with a jet mill pulverizer so as to have an average particle diameter of 8 μm. The powder was pulverized and subjected to a surface treatment using a turbo mill connected to a DS type airflow classifier, and found to have an average particle diameter of 7.5 μm. The toner was further classified to obtain yellow, magenta, and cyan toners each having a volume average particle diameter of 8 μm (5 μm or less, fine powder content: 15%) (0.5 parts of hydrophobic silica was added).

Example 8 (Change of release agent from Example 6) Binder resin Polyol resin (T _sr = 72 ° C., T _fr = 98 ° C.) 10.0 parts Release agent Low molecular weight polypropylene ( (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the above polyol resin and 5.0 parts of a salicylic acid-based compound as a charge controlling agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle diameter of 8 μm.
Surface treatment was performed using a turbo mill connected to an S-type airflow classifier, but the average particle size was 7.5 μm. The powder was further classified to obtain fine particles having a volume average particle size of 8 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17 was replaced by 3.5 parts of a rhodamine pigment, and the volume average particle size was 8%.
μm magenta toner was obtained. Further, C.I. I. A cyan toner having a volume average particle diameter of 8 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17. In each case, the content of fine powder of 5 μm or less was adjusted to be 25%.

Example 9 (Change in type of release agent (polyester wax) from Example 8) Binder resin Polyol resin (T _sr = 72 ° C., T _fr = 98 ° C.) 10.0 parts Release Rice wax (M _pw = 83 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the above polyol resin and 5.0 parts of a salicylic acid-based compound as a charge controlling agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle diameter of 8 μm.
Surface treatment was performed using a turbo mill connected to an S-type airflow classifier, but the average particle size was 7.5 μm. The powder was further classified to obtain fine particles having a volume average particle size of 8 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17 was replaced by 3.5 parts of a rhodamine pigment, and the volume average particle size was 8%.
μm magenta toner was obtained. Further, C.I. I. A cyan toner having a volume average particle diameter of 8 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17. In each case, the content was adjusted so that the content of fine powder of 5 μm or less was 25%.

Comparative Example 1 (No surface treatment step) The same kneaded product as in Example 1 was finely pulverized by a jet mill pulverizer so as to have an average particle diameter of 11.5 μm, and further classified into fine powder to have a volume average particle diameter of 12 μm. (Yellow, magenta, cyan) were obtained (0.5 parts of hydrophobic silica was added).

Comparative Example 2 (Processed with a rotor type pulverizer not connected to an air classifier) The same kneaded product as in Example 1 was finely pulverized with a jet mill pulverizer so as to have an average particle size of 11.5 μm. Surface treatment was performed using a single turbo mill, but the average particle size was 11.5 μm.
Met. Furthermore, fine powder was classified and the volume average particle size was 12 μm.
(Yellow, magenta, cyan) were obtained (0.5 parts of hydrophobic silica was added).

Comparative Example 3 (When the surface treatment was excessively performed) The same kneaded material as in Example 1 was finely pulverized with a jet mill pulverizer so as to have an average particle diameter of 11.5 μm, and the mixture was subjected to a DS type airflow classifier. Surface treatment was performed by setting conditions so that the circulation amount of the treated powder was increased using a connected turbo mill,
The average particle size was 7.5 μm. The powder was further classified to obtain yellow, magenta, and cyan toners having a volume average particle diameter of 8 μm (0.5 parts of hydrophobic silica was added).

Comparative Example 4 (Master batch kneading without release agent) Binder resin Styrene-acrylic copolymer (T _sr = 63 ° C., T _fr = 94 ° C.) 10.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. 73.5 parts of the above-mentioned polyester polymer was added to the obtained pulverized product, and low-molecular-weight polypropylene (M _pw = 85 ° C.) 5.0 as a release agent was used.
, And 5.0 parts of a salicylic acid-based compound as a charge control agent, and melt kneading was performed using a biaxial kneader. The kneaded product was finely pulverized with a jet mill pulverizer so as to have an average particle size of 12 μm, and further subjected to a surface treatment using a turbo mill connected to a DS type airflow classifier.
It was 5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Magenta toner having a volume average particle size of 12 μm was obtained by using 3.5 parts of a rhodamine pigment instead of Pigment Yellow 17. Further, C.I. I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Comparative Example 5 (when the melting point M _pw of the release agent is higher than T _fr -5 (° C.)) Binder resin Polyester polymer (T _sr = 63 ° C., T _fr = 87 ° C.) 10.0 parts Release agent Polyethylene (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the polyester polymer and 5.0 parts of a salicylic acid compound as a charge control agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle size of 12 μm,
Furthermore, surface treatment was performed using a turbo mill connected to a DS type airflow classifier, and the result was an average particle diameter of 11.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17
Was replaced by 3.5 parts of a rhodamine pigment to obtain a magenta toner having a volume average particle diameter of 12 μm. Further, C.I.
I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Comparative Example 6 (when the melting point M _pw of the release agent is lower than T _sr +5 (° C.)) Binder resin Polyester polymer (T _sr = 81 ° C., T _fr = 108 ° C.) 10.0 parts Molding agent Carnauba wax (M _pw = 80 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was mixed and kneaded using a twin-screw kneader. However, the melted release agent was separated from the kneaded product and kneading was impossible. Even when the colorant was changed for magenta and cyan toners, kneading was not possible.

Comparative Example 7 (When the melting point M _pw of the release agent is higher than T _fr -5 (° C.)) Binder resin Polyol polymer (T _sr = 72 ° C., T _fr = 98 ° C.) 10.0 parts Release agent Fischer wax (M _pw = 96 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 73.5 parts of the polyester polymer and 5.0 parts of a salicylic acid compound as a charge control agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle size of 12 μm,
Furthermore, surface treatment was performed using a turbo mill connected to a DS type airflow classifier, and the result was an average particle diameter of 11.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17
Was replaced by 3.5 parts of a rhodamine pigment to obtain a magenta toner having a volume average particle diameter of 12 μm. Further, C.I.
I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Comparative Example 8 (when the melting point M _pw of the release agent is lower than T _sr +5 (° C.)) Binder resin Polyol resin (T _sr = 72 ° C., T _fr = 98 ° C.) 10.0 parts Release agent Polyethylene (M _pw = 75 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was mixed and kneaded using a twin-screw kneader. However, the melted release agent was separated from the kneaded product and kneading was impossible. Even when the colorant was changed for magenta and cyan toners, kneading was not possible.

Comparative Example 9 (Compared to Example 5 with a biaxial kneader) Binder resin Polyester polymer (T _sr = 75 ° C., T _fr = 110 ° C.) 40.0 parts Release agent Small molecule Polypropylene (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was melt-kneaded using a twin-screw kneader, cooled and solidified, and coarsely ground with a hammer mill. To the obtained pulverized product, 43.5 parts of the polyester polymer and 5.0 parts of a salicylic acid compound as a charge controlling agent were added, and the mixture was melt-kneaded using a biaxial kneader. The kneaded material is finely pulverized by a jet mill pulverizer so as to have an average particle size of 12 μm,
Furthermore, surface treatment was performed using a turbo mill connected to a DS type airflow classifier, and the result was an average particle diameter of 11.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Pigment Yellow 17
Was replaced by 3.5 parts of a rhodamine pigment to obtain a magenta toner having a volume average particle diameter of 12 μm. Further, C.I.
I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Comparative Example 10 (when the dispersion diameter of the release agent in the binder resin is smaller than 0.1 μm) Binder resin Polyester polymer (T _sr = 75 ° C., T _fr = 110 ° C.) 10.0 parts Release agent Low molecular weight polypropylene (M _pw = 85 ° C.) 8.0 parts Colorant C.I. I. Pigment Yellow 173.5 parts was subjected to melt kneading by applying a large shearing force to Example 1, cooled and solidified, and coarsely pulverized with a hammer mill. The polyester material 7
3.5 parts, salicylic acid compound 5.0 as charge control agent
And melt kneading was performed for 2 hours using two rolls. The kneaded material was jet-milled with an average particle size of 12 μm.
And further subjected to a surface treatment using a turbo mill connected to a DS type airflow classifier, and found to have an average particle size of 11.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. The fine particles 1
0.5 part of hydrophobic silica was added to and mixed with 00 parts,
A yellow electrophotographic toner was obtained. Next, the coloring agent C.I. I.
Magenta toner having a volume average particle size of 12 μm was obtained by using 3.5 parts of a rhodamine pigment instead of Pigment Yellow 17. Further, C.I. I. Pigment Yellow 17
Was replaced by 3.5 parts of a phthalocyanine pigment to obtain a cyan toner having a volume average particle size of 12 μm.

Comparative Example 11 (No master batch kneading) Binder resin Polyester polymer (T _sr = 75 ° C., T _fr = 110 ° C.) 83.5 parts Release agent Low molecular weight polypropylene (M _pw = 85 ° C.) 8 0.0 part Colorant C.I. I. Pigment Yellow 17 3.5 parts Charge control agent A mixture having a composition consisting of 5.0 parts of a salicylic acid-based compound was melt-kneaded using a twin-screw kneader, solidified by cooling, and coarsely pulverized with a hammer mill. The coarsely pulverized product was finely pulverized with a jet mill pulverizer so as to have an average particle size of 12 μm, and further subjected to a surface treatment using a turbo mill connected to a DS type airflow classifier.
It was 1.5 μm. Further, fine powder was classified to obtain fine particles having a volume average particle size of 12 μm. 0.5 part of hydrophobic silica was added to and mixed with 100 parts of the fine particles to obtain a toner for yellow electrophotography. Next, the coloring agent C.I. I. Magenta toner having a volume average particle size of 12 μm was obtained by using 3.5 parts of a rhodamine pigment instead of Pigment Yellow 17. Further, C.I. I. A cyan toner having a volume average particle diameter of 12 μm was obtained by using 3.5 parts of a phthalocyanine pigment instead of Pigment Yellow 17.

Using the full-color electrophotographic toners obtained in these Examples and Comparative Examples, image evaluation and durability evaluation were performed using a copying machine PRETER550 manufactured by Ricoh Co., Ltd. Table 1 shows the results. The method of measuring the degree of aggregation in these Examples and Comparative Examples was performed using a powder tester. That is, 2.0 g of the toner is used for opening 150
The residual toner amount on each of the sieves after passing through the sieves of μm, 75 μm, and 45 μm was measured, and calculated using the following equation.

Aggregation degree (%) = (A + 0.6 × B + 0.2)
× C) /2.0×100 A: Remaining toner amount (g) on a sieve having an aperture of 150 μm, B:
Remaining amount of toner (g) on sieve with mesh size of 75 μm, C: Remaining amount of toner on sieve with mesh size of 45 μm (g) Color reproducibility can be evaluated by the following method. PR
The lightness L ₁ , hue a ₁ , and saturation b ₁ are obtained for the copied image obtained by the ETER 550 by using the colorimeter X-rete. Similarly, L ₀ , a ₀ , and b ₀ are measured for the original image used for copying, and ΔE (color difference) is obtained using the following equation.

ΔE = [(L ₀ −L ₁ ) ² + (a ₀ −a ₁ ) ² +
(B ₀ -b ₁₎ ^{2] 1/2} △ E ≦ 3: excellent color reproducibility, no problem no 3 <△ E ≦ 5: Although color reproducibility is inferior slightly, level 5 no practical problem <△ E ≦ 7: Inferior in color reproducibility and difficult to use 7 <ΔE: Unusable level Regarding resolution, vertical lines and horizontal lines are 2.0, 2.2, 2.5, 2.. 8, 3.2, 3.
6, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1
With respect to a line image in which book lines are arranged at equal intervals, the extent to which the copied image can faithfully reproduce the space between the lines is evaluated.
That is, the number of lines that can be reproduced per 1 mm is the resolution.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

As is apparent from the above description, according to the method for producing a full-color electrophotographic toner of the present invention, a mixture consisting only of a binder resin, a colorant, and a release agent is melt-kneaded. A masterbatch in which the dispersion of the colorant and the release agent in the binder resin is significantly improved can be obtained. At the time of the kneading, a large shear force that was conventionally required is unnecessary,
A continuous kneader can also be used. Furthermore, after the coarsely pulverized system using the master batch is pulverized by a jet pulverizer or the like, and then spherically processed using a rotor type pulverizer or the like connected to an airflow classifier, it is very easy and efficient. A full-color electrophotographic toner is obtained. Further, in the full-color electrophotographic toner obtained by the production method of the present invention, the dispersion diameter of the colorant in the binder resin is 1 μm or less, the dispersion diameter of the release agent is 0.1 μm or more and 2 μm or less, and the charge rising ratio is When the content is 70% or more, a stable image can be obtained without causing toner scattering, with excellent light transmittance at a high degree of coloration even at a low colorant concentration, excellent color tone reproducibility also in image quality. In addition, good levels of fluidity and storability can be obtained, and also excellent offset resistance at the time of fixing. In particular, the use of a polyester wax or carnauba wax as a release agent has a remarkable effect on quality improvement. Further, by adjusting the content of the fine powder having a volume average particle diameter of 9 μm or less and 5 m or less to 20% or less, the resolution is improved and a clearer image can be obtained.

Continued on the front page (72) Inventor Hiroshi Yaguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Noritaka 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd.

Claims (10)

[Claims] (1) at least a binder resin, a colorant, a release agent,
In an electrophotographic toner containing a charge control agent as a main component,
The dispersion diameter of the colorant in the binder resin is 1 μm or less, and the dispersion diameter of the release agent is 0.1 μm or more and 2 μm or less. When the toner is stirred and mixed for 10 minutes at room temperature and normal humidity with a toner concentration of 5%, the charging amount Q ₆₀₀ obtained under the same conditions 2
The charge amount obtained when 0 sec stirred mixture When Q _20, Z (%) = full electrons (Q ₂₀ / Q ₆₀₀₎ charge rising ratio calculated by × 100 is equal to or less than 70% Photo toner. 2. The melting point M _pw of the release agent according to claim 1, wherein the softening temperature of the binder resin is T _sr and the outflow start temperature of the binder resin is T _fr.
Is in the range of T _sr +5 <M _pw <T _fr −5 (° C.). 3. The full-color electrophotographic toner according to claim 1, wherein the release agent is an ester release agent. 4. The full-color electrophotographic toner according to claim 1, wherein the release agent is carnauba wax. 5. The full-color electrophotographic toner according to claim 1, wherein the volume average particle diameter of the full-color electrophotographic toner is 9 μm or less. 6. The full-color electrophotographic toner according to claim 1, wherein the content of fine powder of 5 μm or less is 20% by number or less. 7. The full-color electrophotographic toner according to claim 1, wherein the degree of aggregation of the full-color electrophotographic toner is 4 to 20% or less. 8. A first stage melt-kneading of a mixture comprising only a binder resin, a colorant and a release agent, and cooling and crushing the obtained kneaded material, the binder resin and the charge control Add the agent 2
A method for producing a toner for full-color electrophotography, comprising performing a melt-kneading step. 9. In 100 parts by weight of the first-stage kneaded material,
9. The method for producing a full-color electrophotographic toner according to claim 8, wherein the first stage melt-kneading is carried out with the colorant contained in the range of 10 to 40 parts by weight and the release agent in the range of 10 to 50 parts by weight. . 10. A primary grinding of raw material to be ground by a jet grinding machine having compressed air and a collision plate as main components, and a fixed container as an outer wall and a center axis of the fixed container are the same. A rotor type pulverizer having a rotating piece as a main component is connected to an airflow classification device, and fine powder is classified by the airflow classification means so that the fine powder is separated from the rotor type pulverizer and the airflow. A method for producing a toner for full-color electrophotography, wherein secondary pulverization is performed by circulating through a classifier.