JP2006145858A - Method of manufacturing kneaded mixture of colorant and method of manufacturing electrostatic charge image developing color toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a kneaded mixture of colorants by which coarse particles of the colorants do not remain and are evenly and finely dispersed in manufacturing the kneaded mixture of the colorants and a method of manufacturing electrostatic charge image developing color toner having sharp grain size distribution and excellent in characteristics as the color toner. <P>SOLUTION: A raw material mixture containing a binder resin, the colorants, and water or a hydrous solvent is mixed in advance and is then subjected to melt kneading and dispersion treatment by using an open roll type continuous kneading machine having heating and cooling functions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a colorant kneaded material suitably used for, for example, a copying machine, a printer, and a fax machine, and a method for producing a color toner for developing an electrostatic image.

  In recent years, the tendency to color copying machines and printers has been increasing year by year. At the same time, due to the demand for high resolution and high image quality with high gradation, there is a need for improved uniformity by reducing the toner particle size and sharpening the distribution. Under such circumstances, the addition amount of the colorant tends to increase, and the finely dispersed or dispersed state of the colorant is becoming important in satisfying the good coloring power and transparency of the color toner. In particular, the fine dispersion and dispersion state of the colorant largely depend on the dispersion method.

  For example, in a color toner manufacturing method using a pulverization method, first, a resin and a colorant raw material mixture are mixed using a container rotating type mixer such as a V blender or a W cone, or a high speed stirring type mixing device such as a Henschel mixer. After mixing a mixture containing a colorant and a raw material mixture containing a high concentration of colorant, the content ratio of the colorant to the resin in the toner is higher than the content ratio of the colorant in the toner, and then kneader, extruder, etc. To produce a colorant master. However, in such a normal method, the dispersion of the colorant becomes insufficient, and sufficient characteristics as a color toner cannot be obtained. Moreover, as a kneading machine used for conventional colorant dispersion, there are kneading methods using two rolls or three rolls. However, these kneaders are batch operations, and various solvents are used as necessary, while changing various conditions such as kneading temperature, roll rotation speed, clearance, rotation ratio, number of passes, etc. Therefore, it is necessary to adjust the viscosity of the kneaded product, and it is necessary for the worker to control it with full control. That is, in order to uniformly control the dispersion state of the colorant in the kneaded product, a highly skilled manufacturing technique is required, which is suitable in terms of productivity, quality, and safety. It is not a manufacturing method.

Here, a manufacturing method in which a colorant master is melt-kneaded using an open roll type continuous kneader having heating and cooling functions has been proposed (see, for example, Patent Document 1).
According to this production method, it is possible to ensure sufficient pigment dispersibility for use as a color toner as compared with the case of melt kneading using a kneader or an extruder, and unlike the two-roll or three-roll, it is easy to use. Kneading with high productivity.
However, when melt kneading using an open roll type continuous kneader, it is necessary to adjust the fluidity of the raw materials. That is, when a raw material mixture is supplied to the roll end using a screw feeder or the like, raw materials are scattered or air is entrained to generate a powder flow, which is mixed in the kneaded material to generate coarse particles. Sometimes. Moreover, a yield may fall because a raw material spills from a roll lower part. As a method for solving such a problem, a method of granulating a raw material mixture by dispersing and fusing the mixture with a stirring shear action and shear heat has been proposed (for example, see Patent Document 2). However, the fluidity of raw materials is improved by granulating by fusing resin with shear heat or by compressing and fusing with media, but the particle size and nature are different. It is difficult to mix and granulate solid-solid raw materials uniformly. Further, in view of the fact that coarse particles of the fused product are likely to be generated, the composition of the raw material may become non-uniform by granulating. In obtaining a uniformly finely dispersed pigment master, it goes without saying that the melting and kneading apparatus and the kneading conditions, as well as the uniform mixing of the raw materials are important.

In general, in order to improve the uniform mixing of raw materials, it is ideal that the raw material has a small particle size, and granulation causes the problem that the uniform mixing of pigment and resin becomes non-uniform. (First problem). In particular, regarding the non-uniformity of the adsorption of the resin to the colorant, there is a toner production method using an emulsification dispersion method which is one of wet toner production methods (hereinafter referred to as chemical toners). It becomes a big problem. For example, a method for producing toner particles by dispersing a colorant and a polyester resin that becomes an anionic self-water-dispersible resin in an organic solvent and then phase-inverting and emulsifying has been proposed (for example, Patent Document 3). reference). Furthermore, a method for producing a toner with a sharp particle size distribution in a high yield by dispersing a colorant and a polyester resin in an organic solvent, then performing phase inversion emulsification, and then performing a coalescing step has been proposed. (For example, see Patent Document 4). That is, in the chemical toner manufacturing method proposed in Patent Documents 3 and 4, for example, the obtained melt-kneaded material is once dissolved and dispersed in an organic solvent. Particles are then formed through the transfer of the medium from the organic layer into the aqueous medium. For this reason, the melted and dispersed colorant takes into account the synergistic effect of the state of dispersion in the organic layer and the state of dispersion in the aqueous medium to form particles. That is, the particle size distribution and the dispersibility of the colorant in the particles are important, but are not described in Patent Document 2 (second problem).
Japanese Patent No. 3010326 Japanese Patent No. 2993624 JP-A-8-21655 JP 2003-122051 A

  The present invention has been made in view of the above problems, and in the production of the colorant kneaded product, the colorant coarse particles do not remain, the method for producing a uniformly finely dispersed colorant kneaded product, and the particle size distribution are An object of the present invention is to provide a method for producing a color toner for developing an electrostatic image that is sharp and has excellent characteristics as a color toner.

  The manufacturing method of the colorant kneaded product of the present invention employs the following configuration in order to solve the above problems. That is, the method for producing the colorant kneaded product of the present invention comprises an open roll type continuous kneading function having heating and cooling functions after previously mixing a raw material mixture containing a binder resin, a colorant, and water or a water-containing solvent. A melt kneading and dispersing process is performed using a machine.

  According to this invention, it is possible to control the fluidity of the raw material mixture by adding water or a hydrous solvent to the raw material mixture. As a result, scattering, powder spillage, and powder flow of the raw material mixture can be avoided, and a uniform colorant master without coarse particles can be formed.

  Further, the method for producing a color toner for developing an electrostatic charge image of the present invention comprises, in an organic solvent, a mixture containing a binder resin mainly composed of a polyester resin having a carboxyl group and a colorant in an organic solvent. A first step of producing a colorant-containing resin liquid by dissolving or dispersing, and a second step of producing a suspension of the colorant-containing fine particles (A) by suspending the colorant-containing resin liquid in an aqueous medium. Wherein the mixture is the colorant kneaded material described above.

  According to the present invention, a color toner having a sharp particle size distribution and excellent characteristics can be produced by using the colorant kneaded material described above.

  According to the method for producing a colorant kneaded product and the method for producing a color toner for developing an electrostatic image according to the present invention, a uniform colorant master in which coarse particles of the colorant do not remain by controlling the fluidity of the raw material mixture. Can be manufactured. In addition, by using this colorant master, a chemical toner obtained by a wet method can be used as a color toner having a sharp particle size distribution even after being dissolved in an organic solvent, dispersed, or formed in an aqueous medium. A color toner having excellent characteristics can be produced.

Hereinafter, an embodiment of a method for producing a color toner for developing an electrostatic image according to the present invention will be described.
The method for producing a color toner for developing an electrostatic image according to the present invention comprises the following first and second steps.
First step: A colorant-containing resin liquid is produced by dissolving or dispersing a binder resin mainly composed of a polyester resin having a carboxyl group as a raw material and a mixture containing a colorant in an organic solvent.
Second step: This colorant-containing resin liquid is mixed with water in the presence of a basic compound to produce a suspension of colorant-containing fine particles (A). The colorant-containing fine particles (A)
(1) Fine particles of an organic solvent in which a colorant and a polyester resin are dissolved or dispersed;
(2) emulsified fine particles in a state where a polyester resin dissolved in an aqueous medium is attached to fine particles of a colorant;
Or
(3) It may be any fine particle in the form of emulsified fine particles in which a microemulsion of a polyester resin swollen with an organic solvent is adhered to the fine particles of the colorant, or a mixed fine particle of those forms.
When the toner is produced by the coalescence method described later, it is preferable to produce a suspension of the colorant-containing fine particles (A) in the state (2) or (3).

  First, the first step will be described in detail. In the first step, a colorant-containing resin liquid is prepared by charging and dissolving or dispersing a binder resin containing a polyester resin as a main component and a mixture containing a colorant in an organic solvent. Here, the mixture is a melt-dispersed kneaded product in which a binder resin, a colorant, and water or a water-containing solvent are finely dispersed by melt kneading using an open roll type continuous kneader having heating and cooling functions. Note that a release agent and other additives can be used together with the mixture as necessary. In any case, it is necessary to finely disperse or dissolve the toner below the toner particle diameter.

The melt-dispersed kneaded product is formed as follows.
First, a raw material mixture containing a polyester resin, a colorant, a mold release agent added as necessary, and water or a water-containing solvent is prepared using an open roll type continuous kneader 1 shown in FIG. Knead by heating to a temperature above the softening point and below the pyrolysis temperature. In addition, it is preferable that the raw material mixture contains 5 mass% or more and 65 mass% or less of water or a water-containing solvent with respect to a coloring agent. This is because the flow rate of the raw material mixture is controlled by controlling the flow rate of the raw material mixture by setting the water or the water-containing solvent to 5% by mass or more and 65% by mass or less, preferably 10% by mass or more and 60% by mass or less with respect to the colorant. This is because the powder can be spilled and the powder flow can be avoided, and the open roll type continuous kneader 1 can be efficiently melt kneaded.
Here, the open roll type continuous kneader 1 is a pair of roll-shaped rotating shafts having a cylindrical shape, a front roll 11 and a rear roll 12, and a raw material supply that is provided at one end of the front and rear rolls 11 and 12 to supply raw materials. And a kneaded material discharge portion 14 that is provided at the other end of the front and rear rolls 11 and 12 and discharges the melt-dispersed kneaded material.

The front and rear rolls 11 and 12 are each formed with a plurality of spiral grooves formed on the surfaces thereof, and are configured to rotate inward from each other. The front and rear rolls 11 and 12 rotate to generate a screw effect, and the plurality of grooves having the spiral shape push out the raw material from the raw material supply unit 13 toward the kneaded product discharge unit 14. As a result, the raw material supplied from the raw material supply unit 13 is melted and kneaded while being compressed and sheared, and transferred to the other end on the kneaded product discharge unit 14 side.
The interiors of the front and rear rolls 11 and 12 are hollow, and the surface temperature of the front and rear rolls 11 and 12 is supplied by supplying a heat medium such as hot water or steam or a coolant such as cooling water to the hollow portions. Is configured to be appropriately controlled. The hollow portion formed inside the front and rear rolls 11 and 12 is one end of the front and rear rolls 11 and 12 on the side of the raw material supply unit 13 with a partition (not shown) provided substantially at the center. Different heat mediums or refrigerants can be supplied between the side and the other end side of the kneaded product discharger 14 side.
In the present invention, the rotational speed of the front roll 11 is controlled to be higher than the rotational speed of the rear roll 12, and the surface temperature of the front roll 11 is the temperature at one end on the raw material supply unit 13 side. For example, the temperature is 110 ° C., and gradually decreases toward the other end, and is adjusted to be, for example, 88 ° C. at the other end on the kneaded material discharge portion 14 side. This is because the supplied raw material is compressed and sheared to suppress the decrease in viscosity due to heat generation so that efficient compression and shearing can be performed. Moreover, by doing in this way, the supplied raw material can be transferred to the other end on the kneaded material discharge portion 14 side in a state of being attached to the front roll 11.

The raw material supply unit 13 is configured such that the raw material is quantitatively supplied by, for example, a screw feeder.
The kneaded product discharge unit 14 includes a pelletizer that collects the melt-dispersed kneaded material adhering to the front roll 11, and forms a kneaded chip by pressing against the front roll 11.

In the open roll type continuous kneader 1 configured in this manner, the granulated product supplied to the raw material supply unit 13 is heated by the surface temperature of the front and rear rolls 11 and 12 and at the same time, the front and rear rolls 11 and 12 are also heated. A rapid compressive force and shearing force are applied in the gap between the two, and the molten material is melted while generating heat, and is repeatedly subjected to compressive shearing between the front and rear rolls 11 and 12, and becomes a melt-dispersed kneaded product. And it is discharged | emitted as a kneading chip | tip in the kneaded material discharge part 14. FIG. The rotation speed (F) of the front roll 11 and the rotation speed (R) of the rear roll 12 are preferably F> R, and the rotation ratio (R / F) is preferably 0.6 to 0.9. preferable. Under such conditions, the kneaded material is wound around the front roll 11 and the kneaded material is not wound around the rear roll 12, so that the material can be easily transferred and recovered in the kneaded material discharge unit 14.
In the case of producing a melt-dispersed kneaded product using the open roll type continuous kneader 1, the content ratio of the colorant contained in the produced toner using a part of the binder resin for producing the toner It is preferable to use a so-called master batch type production method in which a melt-dispersed kneaded material is produced at a higher concentration and then a toner containing a colorant-free resin and the melt-dispersed kneaded material is produced. Further, in the case where a cross-linked polyester resin and a linear polyester resin are used in combination as the binder resin, the content of the colorant contained in the toner after production is included in at least a part of the linear polyester resin. It is preferable that the colorant is melt kneaded and dispersed in advance at a high content ratio. When a crosslinkable resin is used as a resin for a masterbatch, when the open roll type continuous kneader 1 is kneaded with a colorant, the molecular weight is reduced due to cutting of the crosslinkable portion, etc., making it difficult to obtain the desired thermal characteristics. Become. When a linear resin is used as a resin for a masterbatch, such a phenomenon hardly occurs and is preferable.

  The chips of the melt-dispersed kneaded product thus formed are dissolved or dispersed in an organic solvent with a high-speed stirrer such as a despa to prepare a colorant-containing resin liquid (first step). In this case, additives such as a release agent may be mixed after separately preliminarily dispersing in advance to adjust the master kneading chip. In the first step, a high-speed stirrer such as Despa (Asada Iron Works Co., Ltd.) or Homomixa (Special Machine Industries Co., Ltd.) can be used. The blade tip speed at this time is preferably 4 to 30 m / s, particularly preferably 10 to 25 m / s. By using the high-speed stirrer, the binder resin can be efficiently dissolved in the organic solvent, and uniform fine dispersion in the binder resin solution of the colorant contained in the melt-dispersed kneaded product can be achieved. That is, the state of the colorant finely dispersed in advance can be maintained in the binder resin solution by stirring at high speed. When the blade tip speed is lower than 4 m / s, the fine dispersion of the colorant in the binder resin solution becomes insufficient, which is not preferable. On the other hand, if it is higher than 30 m / s, heat generation due to exclusive cutting increases, and it becomes difficult to uniformly stir in combination with volatilization of the solvent.

  Examples of the organic solvent that can be used when the chips of the melt-dispersed kneaded material are dissolved or dispersed in the organic solvent by a high-speed stirrer such as Despa include, for example, pentane, hexane, heptane, benzene, toluene, xylene, cyclohexane, petroleum ether Hydrocarbons such as methylene chloride, chloroform, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, carbon tetrachloride, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and ethyl acetate , Esters such as butyl acetate, and the like are used. These organic solvents can be used in combination of two or more, but from the viewpoint of solvent recovery, it is preferable to use the same type of solvent alone. The organic solvent is preferably one having a low boiling point because it dissolves or disperses the polyester resin, has a relatively low toxicity, and is easy to remove the solvent in a later step. Here, as the organic solvent for dissolving the polyester resin, methyl ethyl ketone and ethyl acetate, which are excellent in solubility and dispersibility, are used. In particular, it is most preferable to use methyl ethyl ketone.

  Next, the second step will be described. The colorant-containing resin liquid obtained above is suspended or dissolved by mixing with water in the presence of an aqueous medium, preferably a basic neutralizing agent that is a basic compound. A suspension is produced. Here, it is preferable to gradually add water to the colorant-containing resin liquid in which the carboxyl group of the polyester resin is neutralized with the base of the basic compound. 50: 50-80: 20 is preferable and, as for the ratio of water and the organic solvent after finishing dripping water, 60: 40-80: 20 is more preferable.

Since the polyester used in the present invention is a polyester resin having a carboxyl group, it is a resin that is easily dispersed in water by neutralizing the carboxyl group (hereinafter referred to as self-water dispersibility) or water-soluble. Further, the acid value of the self-water dispersible or water-soluble polyester resin is preferably 1 to 30 KOHmg / g, and more preferably 3 to 20 KOHmg / g.

This is because when the acid value of the polyester resin is less than 1, production of an aqueous solution in which the polyester resin and the organic solvent are uniformly dissolved or mixed with water, or suspension of fine particles of the polyester resin and the organic solvent suspended in water. Since the suspension is not smoothly produced and coarse particles are generated, it is not preferable.
On the other hand, when the acid value of the polyester resin is greater than 30, the charge amount under various environments is not stable, which is not preferable. The polyester resin having an acid value of 1 to 30 KOHmg / g becomes an anionic type by neutralizing the carboxyl group with a basic compound. As a result, the hydrophilicity of the resin increases, and the resin can be stably dispersed or dissolved without using a dispersion stabilizer or a surfactant.

  The basic compound for neutralization is not particularly limited, and for example, inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine are used. In particular, inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide are preferred. In order to disperse a polyester resin in water or in a medium containing water as a main component and containing an organic solvent (aqueous medium), there is a method of adding a dispersion stabilizer such as a suspension stabilizer or a surfactant. A high shear force is required in the method of emulsifying by adding a turbid stabilizer or a surfactant. This is not preferable because the generation of coarse particles and the particle size distribution become broad. Further, in the case of a cross-linked polyester resin containing a gel content, the particle size distribution becomes more non-uniform, and there is a practical limit. Therefore, in the present invention, a polyester resin that is self-dispersible or water-soluble is used, and the carboxyl group of the polyester resin is neutralized with a basic compound.

  As a method for neutralizing the carboxyl group of the polyester resin with the base of the basic compound, for example, (1) after producing a mixture containing a polyester resin having a carboxyl group, an organic pigment, a release agent and an organic solvent, And (2) a method in which a basic neutralizing agent is mixed in advance in water or an aqueous medium, and the acidic group of the polyester resin contained in the mixture is neutralized when the second step is performed. Etc.

  Here, the amount of the basic compound used is preferably an amount corresponding to 1 to 3 times the amount necessary for neutralizing all carboxyl groups of the polyester resin, and is an amount corresponding to 1 to 2 times. It is more preferable. By adding in excess of the amount required to neutralize the carboxyl groups of the polyester resin in this way, it is possible to prevent the formation of irregularly shaped particles and sharpen the particle size distribution in the coalescence process. can do.

  In the second step, a high-speed stirrer such as Despa (Asada Iron Works Co., Ltd.), Homomixa (Special Machine Industries Co., Ltd.) or Slasher (Mitsui Mining Co., Ltd.), Cavitron (Eurotech Co., Ltd.), or a high-speed disperser Can be used. The blade tip speed at this time is preferably 4 to 30 m / s, and particularly preferably 10 to 25 m / s. By using the high-speed stirrer or the high-speed disperser, a suspension of the colorant-containing resin liquid in the aqueous medium can be efficiently obtained, and the colorant contained in the colorant-containing resin liquid can be obtained in the aqueous medium. Uniform fine dispersion can be achieved. That is, the state of the colorant finely dispersed in the first step in advance can be maintained in an aqueous medium by high-speed stirring. When the blade tip speed is lower than 4 m / s, the fine dispersion of the colorant in the aqueous medium becomes insufficient, which is not preferable. On the other hand, if it is higher than 30 m / s, it is not preferable because scattering tends to be intense and insoluble matter tends to be mixed. The temperature at that time is not particularly limited, but a high temperature is not preferable because the amount of phase inversion water increases. On the other hand, if the temperature is low, the viscosity of the mixture containing the polyester resin and the organic solvent is increased, and the generation of coarse particles is increased. Moreover, as a temperature range of a 2nd process, it is preferable that it is 10 to 50 degreeC, and it is especially preferable that it is 20 to 45 degreeC.

  In the present invention, it is preferable to perform the following third to fourth steps after the second step. The third step will be described in detail below. In the third step, a unitary particle is produced from the suspension or the aqueous solution, and the organic solvent in the unity is removed. In the coalescence method, the particle size and particle size distribution are substantially determined in the first to third steps.

  In the coalescence method, the colorant-containing fine particles (A) suspension is diluted with water to adjust the amount of solvent, and then a dispersion stabilizer is added. And unity is advanced by dripping the aqueous solution of electrolyte in presence of a dispersion stabilizer, and unity is obtained. By adding an electrolyte to the suspension of the colorant-containing fine particles (A), the fine particles are salted out or destabilized, and further, the coalescence progresses by integrating a plurality of fine particles, thereby obtaining a unity. Can do. By adding the electrolyte, not only the colorant-containing fine particles (A) are united, but also the polyester resin fine particles dissolved in the aqueous medium are salted out or destabilized so that the fine particles of the polyester resin are formed. Precipitating and adhering to the surface of the colorant-containing fine particles (A) or the already-integrated colorant-containing fine particles (A), or the polyester resin dissolved in the aqueous medium is salted out or unstable. By being directly attached to the surface of the colorant-containing fine particles (A) or the already integrated colorant-containing fine particles (A), the coalescence progresses and the integral is obtained.

  The suspension of the colorant-containing fine particles (A) obtained in the second step is stabilized in an aqueous medium by the hydration action of the carboxylate of the polyester resin present in the vicinity of the colorant-containing fine particles (A). Is distributed. In the third step, the particles are precipitated or destabilized by adding an electrolyte that destroys or reduces the hydration state of the aqueous medium in which the fine particles are dispersed. Examples of the electrolyte used here include acidic substances such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and oxalic acid. Also, sodium sulfate, ammonium sulfate, potassium sulfate, sodium hydrogen sulfate, ammonium hydrogen sulfate, magnesium sulfate, sodium phosphate, sodium dihydrogen phosphate, sodium chloride, potassium chloride, ammonium chloride, calcium chloride, sodium hydrogen carbonate, ammonium hydrogen carbonate Organic and inorganic water-soluble salts such as sodium acetate can also be effectively used as the electrolyte. These electrolytes may be used alone or as a mixture of two or more kinds of substances. Among them, monovalent cation sulfates and carbonates such as sodium sulfate and ammonium sulfate are preferable in promoting uniform coalescence. The resulting unity is swollen by a solvent, and the hydration state of the particles is unstable due to the addition of an electrolyte. Therefore, the particles are brought together by stirring with low shear (low shearing force). It is preferable that the coalescence proceeds by colliding. It is not preferable to perform the coalescing step under high shear conditions because the particles that have undergone coalescence are split and coalesced simultaneously. It is preferable to control the coalescence process under low shear conditions where only coalescence proceeds without splitting.

  By the way, only by adding an electrolyte or the like, the unitary dispersion in the system becomes unstable, so the unity becomes nonuniform and coarse particles and aggregates may be generated. In order to prevent the formation of an aggregate having a particle size larger than the target particle size by repeating non-uniform coalescence generated by the addition of the electrolyte in this way, before adding the electrolyte, hydroxyapatite It is necessary to add an inorganic dispersion stabilizer such as ionic or nonionic surfactant as a dispersion stabilizer. The dispersion stabilizer used in the third step is required to have a property capable of maintaining the dispersion stability even in the presence of an electrolyte added later. Examples of the dispersion stabilizer having such characteristics include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester. Nonionic emulsifiers such as polyoxyethylene sorbitan fatty acid esters, various pluronics, etc., alkyl sulfate ester type, alkyl sulfonate type anionic emulsifiers, and quaternary ammonium salt type cationic dispersions There are stabilizers. Among these, an anion type and nonionic type dispersion stabilizer is preferable even if it is added in a small amount because it has an effect on the dispersion stability of the system. The cloud point of the nonionic surfactant is preferably 40 ° C. or higher. The above-described surfactants may be used alone or in combination of two or more. Further, in the production method of the present invention, it is possible to prevent non-uniform coalescence by adding an electrolyte in the presence of a dispersion stabilizer (emulsifier). As a result, a sharp particle size distribution is obtained and an improvement in yield is achieved.

  In order to promote uniform coalescence, agitation conditions at the same time are important, and for example, anchor blades, turbine blades, fowler blades, full zone blades, max blend blades, and meniscus blades are used. Among them, it is preferable to use a large wing excellent in uniform mixing properties such as a Max blend wing or a full zone wing. The peripheral speed of the stirring blade for generating a uniform unity is preferably 0.2 to 10 m / s, and more preferably stirring with a low shear of less than 0.2 to 8 m / s. In particular, 0.2 to 6 m / s is preferable. If the peripheral speed of the stirring blade is faster than 10 m / s, fine particles remain, which is not preferable. On the other hand, if the peripheral speed is slower than 0.2 m / s, stirring is not uniform and coarse particles tend to be generated, which is not preferable. Under the above-described conditions, coalescence proceeds only by collision of fine particles, and the coalescence does not dissociate and disperse again. In particular, in the coalescence method, coalescence proceeds preferentially from fine particles, so that generation of ultrafine particles is small and a sharp particle size distribution is achieved, so that an improvement in yield can be achieved.

  When forming a unity, it is preferable to adjust the amount of MEK in the system. Therefore, it is preferable to further dilute the suspension or aqueous solution in the system with water as necessary. Thereafter, a dispersion stabilizer and an electrolyte are sequentially added to perform coalescence. 12-45 mass% is preferable and, as for the amount of the solvent contained in the system before adding electrolyte, it is more preferable that it is 15-30 mass%. If the amount of solvent is less than 12% by mass, the electrolytic mass required for coalescence increases, which is not preferable. On the other hand, if the amount of the solvent is more than 45% by mass, the generation of aggregates due to non-uniform coalescence increases, and the amount of dispersion stabilizer added increases, which is not preferable.

  Further, the amount of the dispersion stabilizer to be used is preferably 0.1 to 3.0% by mass, more preferably 0.3 to 2.0% by mass, for example, based on the solid content. It is especially preferable that it is -1.5 mass%. This is because if it is less than 0.1% by mass, the desired effect of preventing the generation of coarse particles cannot be obtained. On the other hand, when the amount is more than 3.0% by mass, coalescence does not proceed sufficiently even if the amount of the electrolyte is increased, and particles having a predetermined particle diameter cannot be obtained. As a result, fine particles remain and yield. This is because of lowering.

  Moreover, 0.5-15 mass% is preferable with respect to solid content, and, as for the quantity of the electrolyte to be used, it is more preferable that it is 1-12 mass%, and it is especially preferable that it is 1-10 mass%. This is because coalescence does not proceed sufficiently when the amount of electrolyte is less than 0.5% by mass. Further, when the amount of the electrolyte is more than 15% by mass, the coalescence becomes non-uniform, and aggregates and coarse particles are generated to reduce the yield.

  Moreover, 10-50 degreeC is preferable, as for the temporary temperature, it is more preferable that it is 20-40 degreeC, and it is especially preferable that it is 20-35 degreeC. This is because coalescence is difficult to proceed when the temperature is lower than 10 ° C. Moreover, when temperature is higher than 50 degreeC, it is because a coalescence rate will become quick and it will become easy to generate | occur | produce an aggregate and a coarse particle. In the production method of the present invention, it is possible to produce a unity by uniting under a low temperature condition of 20 to 40 ° C., for example.

  By the way, in order to maintain the frictional charging performance satisfactorily, it is effective to prevent the colorant and the like from being exposed on the surface of the toner particles, that is, to have a toner structure in which the colorant and the like are included in the toner particles. The deterioration of the chargeability accompanying the reduction in the toner particle size is caused by the fact that a part of the contained colorant and other additives (usually a release agent) is exposed on the toner particle surface. That is, even if the content (% by mass) of the colorant is the same, the surface area of the toner particle is increased by reducing the particle size, and the ratio of the colorant and the release agent exposed on the surface of the toner particle is increased. As a result, the composition of the toner particle surface changes greatly, and the frictional charging performance of the toner particles changes greatly, making it difficult to obtain an appropriate chargeability.

  The toner particles produced by the above production method are characterized in that a colorant, a release agent and the like are encapsulated in a polyester resin. Whether the colorant, the release agent or the like is not exposed on the toner particle surface can be easily determined by observing the cross section of the particle with a TEM (transmission electron microscope), for example. More specifically, a cross section obtained by embedding the toner particles with a resin and cutting with a microtome is dyed with ruthenium oxide or the like if necessary, and observed with a TEM, so that a colorant or a release agent is included in the particles. It can be confirmed that the particles are dispersed almost uniformly.

  The unitary shape obtained in the third step can be changed from an indeterminate shape to a spherical shape depending on the degree of unity. For example, it can be changed from 0.94 to 0.99 in terms of average circularity. The average circularity can be obtained by taking a SEM (scanning electron microscope) photograph of the finally obtained toner particles and calculating with an image analysis device (manufactured by Luzex AP Co., Ltd.). Since it can be easily obtained by using a flow type particle image analyzer FPIP-1000 manufactured by Sysmex Corporation, a value measured by this apparatus is used as an average circularity in this specification.

  The toner particles preferably have an average circularity of 0.96 or more, and more preferably 0.97 or more. This is because the powder fluidity and the transfer efficiency are improved by setting the average circularity to a substantially spherical or spherical shape having an average circularity of 0.97 or more. . In particular, as the particle size decreases, the difference in terms of powder flowability, transfer efficiency, and toner consumption increases between spherical and irregular shapes.

  Next, the organic solvent is removed from the aqueous medium containing the coalescence obtained in the coalescence process. The unity obtained in the uniting step contains an organic solvent and swells, so that it tends to aggregate under high temperature conditions. Therefore, it is preferable to carry out the desolvation under reduced pressure in order to carry out the desolvation quickly under a low temperature condition.

  Next, the fourth step will be described in detail. In the fourth step, the unity obtained in the third step is separated from the aqueous medium and dried. Separation from the aqueous medium can be performed by a known and commonly used means such as a centrifugal separator, a filter press, a belt filter or the like. Subsequently, the toner particles can be obtained by drying the particles. Here, in the case where a dispersion stabilizer is used in the third step, it is preferable to wash more sufficiently.

  As the drying method, any known and commonly used method can be adopted. For example, a method in which the toner particles are dried under normal pressure or reduced pressure at a temperature at which the toner particles are not thermally fused or aggregated, and a method in which freeze drying is performed. It is done. In addition, a method of simultaneously separating and drying the toner particles from the aqueous medium using a spray dryer or the like can be used. In particular, a method in which powder is stirred and dried under reduced pressure while heating at a temperature at which toner particles are not thermally fused or agglomerated, or a flash jet drier that instantly dries using a heated and dried air stream (Seishin Corporation) Etc.) is preferable because it is efficient.

  The toner particle size distribution is preferably 50% volume particle size / 50% number particle size of 1.25 or less, as measured with a multisizer TAII type (aperture tube diameter: 100 μm) manufactured by Coulter, Inc. The following is more preferable. This is because it is easy to obtain a good image when it is 1.25 or less. The GSD (geometric standard deviation) is preferably 1.30 or less, and more preferably 1.25 or less. The GSD is a value obtained from the square root of (16% volume particle size / 84% volume particle size) as measured by a multisizer TAII type manufactured by Coulter. The smaller the GSD value, the sharper the particle size distribution and the better the image.

  The volume average particle diameter of the toner is preferably in the range of 1 to 13 μm from the viewpoint of the obtained image quality, etc., and about 3 to 10 μm is more preferable because it can be easily matched with the current machine. For a color toner, a range in which the volume average particle diameter is 3 to 8 μm is preferable. When the volume average particle size is reduced, not only the resolution and gradation are improved, but also the thickness of the toner layer forming the printed image is reduced and the toner consumption per page is reduced. It is.

The polyester resin used in the present invention is preferably a mixture of a cross-linked polyester resin and a linear polyester resin, and can be obtained by reacting a compound selected from the following raw materials.
The cross-linked polyester is preferably produced by reacting a divalent polybasic acid or a derivative thereof, a divalent aliphatic polyhydric alcohol, and a polyvalent compound as a cross-linking agent. In particular, it is preferable to produce by reacting a divalent polybasic acid or a derivative thereof, a divalent aliphatic polyhydric alcohol, and a polyvalent epoxy compound as a crosslinking agent.
The linear polyester resin is produced by reacting a divalent polybasic acid with a divalent alcohol. In particular, it is preferable to produce by reacting a divalent polybasic acid with a divalent aliphatic alcohol.

  The following divalent basic acids can be used as the acid component used when producing the cross-linked polyester resin and the linear polyester resin. For example, divalent basic acid compounds include phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride, tetrahydroanhydride Examples thereof include dicarboxylic acids such as phthalic acid, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, azelaic acid, sebacic acid, and derivatives or esterified products thereof.

  In addition, as the divalent aliphatic alcohol component, the following alcohols can be used. Examples of the divalent aliphatic alcohol include 1,4-cyclohexanedimethanol, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, butanediol, pentanediol, and hexanediol. Diols such as polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide random copolymer diol, ethylene oxide-propylene oxide block copolymer diol, ethylene oxide-tetrahydrofuran copolymer diol, polycaprocactone diol It is done.

Use of an aliphatic alcohol in the cross-linked polyester resin and the linear polyester resin is preferable because compatibility with waxes is improved and offset resistance is improved. Moreover, fixing property at low temperature is improved by softening the polyester main chain.
When producing a crosslinked polyester resin, a polyvalent epoxy compound is further used as a crosslinking agent. Examples of such compounds include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, ethylene glycol diglycidyl ether, hydroquinone diglycidyl ether, N, N-diglycidyl aniline, glycerin triglycidyl ether. , Trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetrakis 1,1,2,2 (p-hydroxyphenyl) ethane tetraglycidyl ether, cresol novolac type epoxy resin, phenol novolac type epoxy Resin, polymer or copolymer of an epoxy group-containing vinyl compound, epoxidized resorcinol-acetone condensate, partial energy Carboxymethyl polybutadiene, polymers of vinyl compounds having an epoxy group, or a copolymer, such as semi-drying or drying fatty acid ester epoxy compound. Among the above compounds, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylol ethane Triglycidyl ether and pentaerythritol tetraglycidyl ether are more preferably used.

  Specifically, Epiklon 850, Epicron 1050, Epicron 2055, Epicron 3050, etc. manufactured by Dainippon Ink and Chemicals, Inc. as examples of bisphenol A type epoxy resins, and Dainippon Ink Chemical Industries, Ltd. as examples of bisphenol F type epoxy resins ( Epicron 830, Epicron 520, etc. manufactured by Dainippon Ink & Chemicals, Inc. as an example of orthocresol novolak type epoxy resin, N-660, N-665, N-667, N-670, N-673 N-680, N-690, N-695 and the like, and examples of the phenol novolac type epoxy resin include Epicron N-740, N-770, N-775, N-865, etc. manufactured by Dainippon Ink and Chemicals, Inc. Can be mentioned. Examples of the polymer or copolymer of a vinyl compound having an epoxy group include a homopolymer of glycidyl (meth) acrylate, an acrylic copolymer, and a copolymer with styrene.

  Moreover, the epoxy compound mentioned above can also be used in combination of 2 or more types, Furthermore, the mono epoxy compound described below can also be used together as a modifier | denaturant of resin. Examples of the monoepoxy compound that can be used at the same time include phenyl glycidyl ether, alkylphenyl glycidyl ether, alkyl glycidyl ether, alkyl glycidyl ester, glycidyl ether of alkylphenol alkylene oxide adduct, α-olefin oxide, monoepoxy fatty acid alkyl ester, etc. Is mentioned.

  By using these monoepoxy compounds in combination, fixability and resistance to offset at high temperatures are improved. Among these, alkyl glycidyl esters are particularly preferably used. Specific examples include neodecanoic acid glycidyl ester (Cardura E; manufactured by Shell Japan).

  The cross-linked polyester resin and the linear polyester resin can be obtained, for example, by performing a dehydration condensation reaction or a transesterification reaction in the presence of a catalyst using the raw material components described above. The reaction temperature and reaction time at this time are not particularly limited, but are usually 150 to 300 ° C. and 2 to 24 hours.

  As the catalyst for performing the above reaction, for example, tetrabutyl titanate, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, paratoluenesulfonic acid, and the like can be used as appropriate.

  The use ratio of the crosslinked polyester resin and the linear polyester resin used in the present invention is preferably (mass of crosslinked polyester resin) / (mass of linear polyester resin) = 5 / 95-60 / 40, 10/90 to 40/60 is more preferable, and 15/85 to 30/70 is particularly preferable. When the ratio of the cross-linked polyester resin is less than 5% by mass, the hot offset resistance is lowered, which is not preferable. In addition, the coalescence speed is lowered, and the dispersibility of wax, colorant and the like is lowered, which is not preferable. On the other hand, if it is more than 60% by mass, the melt viscosity (T1 / 2 temperature) increases and the low-temperature fixability decreases, which is not preferable.

The glass transition temperature (Tg) of the cross-linked polyester resin is preferably 60 to 85 ° C, and particularly preferably 60 to 75 ° C. When the glass transition temperature (Tg) is lower than 60 ° C., a blocking phenomenon (thermal aggregation) tends to occur when the toner is stored, transported, or exposed to a high temperature inside the developing device of the machine. Further, if the glass transition temperature (Tg) is higher than 85 ° C., the low-temperature fixability is lowered, which is not preferable.
The glass transition temperature (Tg) of the linear polyester resin is preferably 50 to 70 ° C, and particularly preferably 55 to 65 ° C. When the glass transition temperature (Tg) is lower than 50 ° C., a blocking phenomenon (thermal aggregation) tends to occur when the toner is stored, transported, or exposed to a high temperature inside the developing device of the machine. On the other hand, if the glass transition temperature (Tg) is higher than 70 ° C., the low-temperature fixability is lowered, which is not preferable.

Further, the softening point of the cross-linked polyester resin is preferably 160 ° C. or higher, and more preferably 160 ° C. to 220 ° C. Here, the softening point of the cross-linked polyester resin is more preferably 170 ° C to 200 ° C, and particularly preferably 170 ° C to 190 ° C. This is because when the softening point is less than 160 ° C., the toner tends to cause agglomeration phenomenon, which is likely to cause trouble during storage or printing, and when it exceeds 220 ° C., the fixability tends to deteriorate. is there.
Moreover, as a softening point of a linear polyester resin, it is preferable that it is 90 degreeC or more, and it is preferable that it is 90 to 130 degreeC especially. Here, the softening point of the linear polyester resin is more preferably 90 ° C to 120 ° C, and particularly preferably 95 ° C to 110 ° C. As with the cross-linked polyester resin, when the softening point is less than 90 ° C., the glass transition temperature is lowered, and the toner tends to cause aggregation phenomenon, which is likely to cause trouble during storage or printing. If the temperature exceeds 130 ° C., the fixability tends to deteriorate.

  The softening point of the mixture of the cross-linked polyester resin and the linear polyester resin is preferably 100 ° C to 150 ° C. Here, the softening point of the mixture is more preferably 110 ° C to 140 ° C, and particularly preferably 110 ° C to 135 ° C. As described above, when the softening point is less than 100 ° C., the toner tends to agglomerate, which is likely to cause trouble during storage and printing. When the softening point exceeds 150 ° C., the fixing property is deteriorated. It is because it becomes easy to do.

The softening point of the polyester resin is defined by a T1 / 2 temperature measured using a flow tester CFT-500 manufactured by Shimadzu Corporation, which is a constant load extrusion type capillary rheometer. The measurement conditions with the flow tester were: piston cross-sectional area 1 cm ² , cylinder pressure 0.98 MPa, die length 1 mm, die hole diameter 1 mm, measurement start temperature 50 ° C., temperature increase rate 6 ° C./min, sample mass 1.5 g. Performed under conditions.

  In the production method of the present invention, a release agent can be used. In this case, the release agent may be selected from hydrocarbon waxes such as polypropylene wax, polyethylene wax, and Fischer-Tropsch wax, and natural ester waxes such as synthetic ester wax, carnauba wax, and rice wax. A mold is used. Of these, natural ester waxes such as carnauba wax and rice wax, synthetic ester waxes obtained from polyhydric alcohols and long-chain monocarboxylic acids, and hydrocarbon waxes such as Fiescher-Tropsch wax are preferably used. As the synthetic ester wax, for example, WEP-5 (manufactured by NOF Corporation) is preferably used. If the content of the release agent is less than 1% by mass, the releasability is likely to be insufficient, and if it exceeds 40% by mass, the wax is likely to be exposed on the toner particle surface, and the chargeability and storage stability are reduced. Since it becomes easy, the inside of the range of 1-40 mass% is preferable.

  In addition, a charge control agent can be used. The positively chargeable charge control agent is not particularly limited, and known and commonly used nigrosine compounds, quaternary ammonium compounds, onium compounds, triphenylmethane compounds, and the like can be used for toner. A basic group-containing compound such as an amino group, an imino group, or an N-heterocycle, such as a tertiary amino group-containing styrene acrylic resin, can also be used in combination with the nigrosine dye as a positively chargeable charge control agent. Depending on the application, a small amount of a negative charge control agent such as an azo dye metal complex or a salicylic acid derivative metal complex salt may be used in combination. Negative charge control agents include trimethylethane dyes, metal complexes of salicylic acid, metal complexes of benzylic acid, copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex azo dyes, azochrome complexes Examples thereof include dyes, calixarene-type phenol condensates, cyclic polysaccharides, resins containing carboxyl groups and / or sulfonyl groups.

  The content of the charge control agent is preferably 0.01 to 10% by mass. It is especially preferable that it is 0.1-6 mass%.

  There is no restriction | limiting in particular about a coloring agent, A well-known and usual thing is used. For example, black colorants that can be used in the toner of the present invention include carbon blacks such as furnace black, channel black, acetylene black, thermal black, and lamp black classified according to the production method, or C.I. I. Pigment Black 11 and other iron oxide pigments, C.I. I. And iron-titanium complex oxide pigments such as Pigment Black 12.

  As the blue colorant, phthalocyanine C.I. I. Pigment Blue 1, 2, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15, 16, 17: 1, 27, 28, 29, 56, 60, 63, and the like. The blue colorant is preferably C.I. I. Pigment Blue 15: 3, 15, 16, 60, and most preferably C.I. I. Pigment Blue 15: 3,60.

  Examples of yellow colorants include C.I. I. Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 24, 55, 65, 73, 74, 81, 83, 87, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 116, 117, 120, 123, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 156, 168, 169, 170, 171, 172, 173, 180, 185 and the like. Preferably, C.I. I. Pigment Yellow 17, 74, 93, 97, 110, 155 and 180, more preferably C.I. I. Pigment Yellow 74, 93, 97, 180, and C.I. I. Pigment Yellow 93, 97, 180 is preferable.

  Further, examples of red colorants include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17, 18, 22, 23, 31, 37, 38, 41, 42, 48: 1 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 54, 57: 1, 58: 4, 60: 1 63: 1, 63: 2, 64: 1, 65, 66, 67, 68, 81, 83, 88, 90, 90: 1, 112, 114, 115, 122, 123, 133, 144, 146, 147, 149,150,151,166,168,170,171,172,174,175,176,177,178,179,185,187,188,189,190,193,194,202,208,209,214, 216, 220, 221, 224, 2 42,243,243: 1,245,246,247 etc. are mentioned. Preferably, C.I. I. Pigment Red 48: 1, 48: 2, 48: 3, 48: 4, 53: 1, 57: 1, 122 and 209, most preferably C.I. I. Pigment Red 57: 1, 122, and 209.

  The content of these colorants is preferably 1 to 20% by mass with respect to the whole toner. Especially, it is more preferable that it is 2-18 mass%, and it is especially preferable that it is 2-15 mass%. These colorants can be used alone or in combination of two or more.

  The dried toner particles can be used as a developer as they are, but it is preferable to add known external additives such as inorganic oxide fine particles and organic polymer fine particles to the toner particle surfaces as external additives for toner. . Hydrophobic silica, inorganic fine particles such as titanium oxide, or organic fine particles are externally added to toner particles to improve physical properties such as fluidity and chargeability when used as a dry developer by electrostatic printing. effective. As the type of the external additive, hydrophobic silica treated with various silicone oils is preferably used. Examples thereof include hydrophobic silica treated with dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil, and olefin-modified silicone oil. The external addition method is processed using a known and commonly used model.

  A two-component electrostatic image developer can be obtained by mixing a carrier with the toner particles. The electrostatic charge image developer comprises a toner produced by the production method of the present invention and a magnetic carrier, preferably a magnetic carrier whose surface is coated with a resin.

  Iron powder, magnetite, ferrite, etc. used in the usual two-component development system can be used as the carrier core agent (magnetic carrier) used in the electrostatic image developer, but the true specific gravity is low, the resistance is high, and the environment Ferrite or magnetite that is excellent in stability and easy to be spherical and has good fluidity is preferably used. The shape of the core agent can be used without any problem, for example, spherical or irregular. The average particle size is generally 10 to 200 μm, but 30 to 110 μm is preferable for printing a high resolution image.

  Examples of the coating resin for coating these core agents include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether polyvinyl ketone, vinyl chloride / vinyl acetate. Copolymers, styrene / acrylic copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluorine resins, (meth) acrylic resins, polyesters, polyurethanes, polycarbonates, phenol resins, amino resins, melamine resins, benzoguanamine resins Urea resin, amide resin, epoxy resin and the like can be used.

  Among these, silicon resins and (meth) acrylic resins are particularly excellent in charging stability and coating strength, and can be used more suitably. In addition, the charging characteristics of a developer composed of toner particles and a carrier can be adjusted by adjusting the coating amount of a coating agent such as silicon, adding a charge control agent, or adding a conductive material typified by carbon. That is, the resin-coated carrier used in the present invention is a resin-coated magnetic carrier coated with one or more resins selected from silicon resin and (meth) acrylic resin using ferrite or magnetite as a core agent. It is preferable to adjust the charging characteristics by adding a charge control agent, carbon or the like to the coating agent.

  Further, the toner produced by the production method of the present invention can be used in a normal non-magnetic one-component developing type printing apparatus, a two-component developing type printing apparatus, a magnetic one-component developing type printing apparatus, or the like. Further, on a flexible printed circuit board having an electrode having a function of adjusting a toner passing amount of powder toner that is frictionally charged using a nonmagnetic one-component developing device having a developer carrying roll and a layer regulating member. Therefore, it can be suitably used for a so-called toner jet type printer in which an image is formed by spraying directly on the paper on the back electrode through the hole. The toner produced by the production method of the present invention forms an electrostatic image on the latent image carrier, and develops the obtained electrostatic image using a developer carried on the developer carrier, Printing can be performed by an image forming method in which the toner image formed on the cargo image carrier is transferred onto a transfer material such as paper or film, and the toner image on the transfer material is thermally fixed by a heat roll.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In this example, unless otherwise indicated, “part” means part by mass, and “water” means deionized water. An example of the synthesis of the binder resin used for adjusting the toner first is shown below.

<Crosslinked polyester resin>
(Resin synthesis example 1)
Terephthalic acid 252 parts by mass Isophthalic acid 63 parts by mass Propylene glycol 122 parts by mass Neopentyl glycol 21 parts by mass Ethylene glycol 12 parts by mass Tetrabutyl titanate 2.5 parts by mass Epicron 830 9.4 parts by mass Cardura E 9.0 parts by mass

Here, Epicron 830 is a bisphenol F type epoxy resin manufactured by Dainippon Ink and Chemicals, Inc., and has an epoxy equivalent of 170 (g / eq). Cardura E is an alkyl glycidyl ester manufactured by Shell Japan, and has an epoxy equivalent of 250 (g / eq).
The above raw materials were put into a 2 L glass four-necked flask and a thermometer, a stirring rod and a nitrogen introducing tube were attached, and the reaction was carried out in an electric heating mantle heater at 240 ° C. for 10 hours under a normal pressure nitrogen stream. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by a softening point according to ASTM E28-517, and the reaction was terminated when the softening point reached 160 ° C.

  The obtained polymer was a colorless solid, and had an acid value of 11.8, a glass transition temperature of 74 ° C. by DSC measurement, and a softening point (T1 / 2) by a flow tester of 180 ° C.

<Linear polyester resin>
(Resin synthesis example 2)
Terephthalic acid 189 parts by mass Isophthalic acid 126 parts by mass Neopentyl glycol 104 parts by mass Ethylene glycol 62 parts by mass Tetrabutyl titanate 2.5 parts by mass

  Put the above raw materials into a glass 2L four-necked flask, attach a thermometer, stirrer and nitrogen inlet tube, react in an electric heating mantle heater at 240 ° C for 12 hours under normal pressure nitrogen flow, and then depressurize sequentially. The reaction was continued at 10 mmHg. The reaction was followed by a softening point according to ASTM E28-517, and the reaction was terminated when the softening point reached 104 ° C.

  The obtained polymer was a colorless solid having an acid value of 11.2, a glass transition temperature of 56 ° C. by DSC measurement, and a softening point (T1 / 2) by a flow tester of 106 ° C. Table 1 shows the resin types, acid component molar ratios, and alcohol component molar ratios of Resin Synthesis Examples 1 and 2.

  In Table 1, TPA represents terephthalic acid, IPA represents isophthalic acid, PG represents propylene glycol, NPG represents neopentyl glycol, and EG represents ethylene glycol.

(Example of preparation of colorant kneaded material)
A 20 L Henschel mixer (made by Mitsui Mining Co., Ltd.) equipped with ST / A0 blades is charged with 2000 parts of a colorant, and then a predetermined amount of water, a water-containing solvent, or a solvent is charged as necessary, and stirred at 698 rpm for 1 minute. Thereafter, 1000 parts of the polyester resin of Synthesis Example 2 was charged and stirred under the same conditions, and then 2000 parts of the polyester resin of Synthesis Example 2 was charged and stirred at 698 rpm for 2 minutes to obtain a raw material mixture. Next, kneading was performed using the open roll type continuous kneader 1 under the conditions shown in Table 2, and the colorant kneaded materials of Examples 1 to 9 and Comparative Examples 1 to 4 shown in Table 3 were obtained. In Table 2, the kneading zone temperature setting indicates the temperature of water flowing in the hollow portion of the rear roll 12 in the upper stage and the temperature of water flowing in the hollow portion of the front roll 11 in the lower stage, and the arrows indicate the direction of water flow. Is shown. Further, in the column of kneading zone temperature setting, the left side is the raw material supply unit 13 side, and the right side is the kneaded product discharge unit 14 side. That is, the water in the hollow portion of the rear roll 12 circulates from the raw material supply unit 13 side toward the kneaded product discharge unit 14 side.

The colorants used in Table 3 are as follows.
Cyan: Cyan pigment “Ket-111” (Pigment Blue 15: 3) manufactured by Dainippon Ink & Chemicals, Inc.
Yellow: Yellow pigment “Chrophtal Yellow 3G” (Pigment Yellow 93) manufactured by Ciba Specialty Chemicals
Magenta: Magenta pigment “Permanent Rubin F6B” manufactured by Clariant Japan (Pigment Red 184)
Carbon black: “Elftex 8” manufactured by Cabot

  The following characteristics evaluation was performed on the colorant kneaded materials of Examples and Comparative Examples thus obtained.

(Evaluation methods)
(1) Raw material dropping This is a phenomenon in which the raw material falls without being fused between the front roll and the rear roll, which causes a decrease in yield. A material with almost no material drop ◎, a material drop of less than 1% of the kneaded product ○, a material drop of 1 to 5% of the kneaded product △ a material drop more than 5% The thing with was made into x.

(2) Raw material scattering This is a phenomenon in which the raw material mixed powder is scattered from the feeder part or the roll part when the supplied raw material is supplied to the roll, which causes coarse particles to remain due to mixing of the unkneaded material. Moreover, it becomes a cause of a yield fall. When the material was not visually scattered, ◎, when the material was slightly scattered, ○, when the material was clearly confirmed, Δ, and when a large amount of material was scattered, x.

(3) Short path of raw material When the raw material is supplied to the roll, jetting properties are produced by the entrainment of air, and flushing occurs. Due to the occurrence of flushing, the surface of the kneaded product or the rear roll is contaminated by the raw material mixture, and as a result, the unkneaded product is mixed, causing coarse particles to remain. Visually, the case where the rear roll was not contaminated by the raw material mixture was indicated as ◯, the case where the raw material mixture was thinly adhered on the rear roll was indicated as Δ, and the case where the rear roll was colored and contaminated was indicated as x.

(4) Coexistence of coarse particles Each colorant kneaded product obtained in Examples and Comparative Examples was diluted with the resin of Example 2 and MEK, and the finely dispersed state of the colorant was measured with a 400 times optical microscope. Existence of presence or absence, coarse particles are uniformly dispersed finely, ◎, 1 to 3 μm coarse particles remain slightly ○, and 3 to 5 μm coarse particles slightly remain △ means that coarse particles of 5 μm or more remain.
Table 4 shows the evaluation results of (1) to (4).

  As shown in Table 4, it can be seen that wetting the raw material mixture with water or a water-containing solvent significantly improves problems such as raw material dropping, raw material scattering, and short path of the raw material. As a result, coarse particles of the colorant in the kneaded product can be greatly reduced. In particular, when a water-containing solvent is used, raw material dropping and raw material scattering are remarkably improved. When the solvent is used alone, the same effect can be obtained, but the residual amount of coarse particles slightly increases because the torque at the time of kneading decreases and the material to be kneaded is not sufficiently sheared. On the other hand, in the comparative examples in which the raw material mixture is not wetted with water, a water-containing solvent, or a solvent, raw material dropping, raw material scattering, and short path of the raw material occur, and it is impossible to obtain a uniform kneaded product as well as productivity. I understand.

<Example of production of mother toner by coalescence method>
(Example of preparation of release agent master dispersion)
Carnauba wax “Carnauba Wax No. 1” (imported by Yoko Kato) 50 parts, linear polyester resin (resin synthesis example 2) 50 parts and methyl ethyl ketone 150 parts were premixed with Despa and then Starmill LMZ-10 (Ashizawa Fine) (Made by Tech Co., Ltd.), and a release agent fine dispersion having a solid content of 40% by mass was prepared.

(Example of mill base preparation)
The above release agent dispersion, colorant master solution, or colorant master chip, dilution resin (additional resin), methyl ethyl ketone, with a solid content of 55% and a temperature condition in the range of 30 to 40 ° C. at 3600 rpm of Despa The mixture was mixed for 3 hours to dissolve and disperse. The resulting mixture was readjusted to a solid content of 55% to make a mill base. The composition of the produced mill base is shown in Table 5.

(Application 1)
A cylindrical 2 L separable flask having a Despa blade as a stirring blade is charged with 545.5 parts of Millbase MB-1 (solid content: 300 parts), and then 52 parts of 1N ammonia water is added. After stirring, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Subsequently, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max Blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 200 parts of a 3.0% ammonium sulfate aqueous solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 50 parts of an ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was dropped at 5 g / min, and then the stirring was continued to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.7%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). I understood it.

(Application example 2)
Millbase MB-2 was charged to 545.5 parts (solid content: 300 parts) in a cylindrical 2 L separable flask having a Despa blade as a stirring blade, and then 74.0 parts of 1N ammonia water was added. After stirring well, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Next, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 177 parts of a 3.8% aqueous ammonium sulfate solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 20 parts of an ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was dropped at 5 g / min, and the mixture was then stirred to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.3%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). I understood it.

(Application 3)
Millbase MB-3 (545.5 parts, solid content: 300 parts) was charged into a cylindrical 2 L separable flask having a Despa blade as a stirring blade, and then 74.0 parts of 1N ammonia water was added. After stirring well, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Subsequently, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max Blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 189 parts of a 3.5% aqueous ammonium sulfate solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 30 parts of ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was added dropwise at 5 g / min, and then stirred to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.6%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). I understood it.

(Application 4)
Millbase MB-4 was charged to 545.5 parts (solid content: 300 parts) in a cylindrical 2 L separable flask having a Despa blade as a stirring blade, and then 52 parts of 1N ammonia water was added. After stirring, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Next, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max Blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 200 parts of a 3.0% ammonium sulfate aqueous solution (first stage electrolyte) was dropped at 5 g / min. Thereafter, the rotational speed was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 35 parts of an ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was dropped at 5 g / min, and then the stirring was continued to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.5%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). I understood it.

(Application example 5)
A cylindrical 2 L separable flask having a Despa blade as a stirring blade was charged with 545.5 parts of Millbase MB-5 (solid content: 300 parts), and then 52 parts of 1N ammonia water was added. After stirring, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Subsequently, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max Blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 200 parts of a 3.0% ammonium sulfate aqueous solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 50 parts of an ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was dropped at 5 g / min, and the mixture was then stirred to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.7%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). As a result, coarse particles of the colorant were observed. Observed and found that some were exposed on the particle surface.

(Application example 6)
A cylindrical 2 L separable flask having a Despa blade as a stirring blade was charged with 545.5 parts of Millbase MB-6 (solid content: 300 parts), and then 74.0 parts of 1N ammonia water was added. After stirring well, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Next, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 177 parts of a 3.8% aqueous ammonium sulfate solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 20 parts of an ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was dropped at 5 g / min, and the mixture was then stirred to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.3%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). As a result, coarse particles of the colorant were observed. Observed and found that some were exposed on the particle surface.

(Application example 7)
A cylindrical 2 L separable flask having a Despa blade as a stirring blade is charged with 545.5 parts of Millbase MB-7 (solid content: 300 parts), and then 74.0 parts of 1N ammonia water is added thereto, and 3600 rpm is added by Despa at 3600 rpm. After stirring well, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

  Subsequently, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max Blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 189 parts of a 3.5% aqueous ammonium sulfate solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 30 parts of ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was added dropwise at 5 g / min, and then stirred to dilute when the particle size grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.6%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). As a result, coarse particles of the colorant were observed. Observed and found that some were exposed on the particle surface.

(Application 8)
A cylindrical 2 L separable flask having a Despa blade as a stirring blade was charged with 545.5 parts of Millbase MB-8 (solid content: 300 parts), and then 52 parts of 1N ammonia water was added. After stirring, the temperature was adjusted to 23 ° C. Subsequently, the stirring speed was changed to 7000 rpm and 370 parts of deionized water was added dropwise at 5 g / min to prepare an emulsified dispersion. The peripheral speed of the stirring blade at this time was 14.7 m / s. Further, when the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and release agent fine particles were dispersed. Next, 200 parts of deionized water was added to adjust the amount of solvent.

Subsequently, the stirring speed was changed to 3600 rpm, and 2.2 parts of an anionic emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with 30 parts of water and added. Thereafter, the stirring blade was changed to a Max Blend blade, the temperature was adjusted to 25 ° C., the rotation speed was adjusted to 400 rpm, and 200 parts of a 3.0% ammonium sulfate aqueous solution (first-stage electrolyte) was dropped at 5 g / min. Thereafter, the number of rotations was adjusted to 158 rpm, and stirring was continued until the particle size reached 4 μm. Subsequently, 35 parts of an ammonium sulfate aqueous solution (second stage electrolyte) whose concentration of ammonium sulfate was changed to 4.0% was dropped at 5 g / min, and then the stirring was continued to dilute when the particle diameter grew to 7.8 μm. Water was added to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.34 m / s. Moreover, the addition amount with respect to solid content of electrolyte was 2.5%. Thereafter, methyl ethyl ketone was distilled off under reduced pressure until the degree of vacuum was 4 kPa. The slurry after removal of the solvent was subjected to solid-liquid separation and washing repeatedly, and then the obtained wet cake was dried with a freeze dryer to obtain mother toner particles. After embedding the obtained mother toner in a resin, a flaky sample was prepared with a microtome, and the dispersion state of the colorant in the particles was observed with a TEM (transmission electron microscope). As a result, coarse particles of the colorant were observed. Observed and found that some were exposed on the particle surface.
<Evaluation method of toner properties>
(1) Measurement of particle size and particle size distribution A sample is prepared by suspending the mother toner after drying in water containing a surfactant. Subsequently, the particle size and particle size distribution of the mother toner were measured using a Coulter Counter Multisizer TAII. The measurement results are shown in Table 6.

(2) Measurement of average circularity The average circularity can be obtained by taking a SEM (scanning electron microscope) photograph of toner particles, and measuring and calculating it. Determined by a particle image analyzer FPIP-1000 (manufactured by Sysmex Corporation). The flow-type particle image analyzer FPIP-1000 is an apparatus that captures the size and shape of fine particles such as toner particles, and particle imaging is performed as follows.

  First, a sample is prepared by suspending a small amount of the dried mother toner in water containing a surfactant. Next, this sample is allowed to flow down into a transparent and flat cell provided in the flow type particle image analyzer FPIP-1000. A light source that emits pulsed light is installed on one side of the cell, and an imaging camera is provided on the opposite side of the cell so as to face the light source. The toner particles in the sample flowing down in the FPIP-1000 cell are captured as a still image by a camera facing the light source through the cell when irradiated with pulsed light.

  Based on the image of the toner particle thus captured, the contour of each toner particle is extracted by the image analysis device, and the projected area and peripheral length of the toner particle image (peripheral length of the toner particle projected image) are calculated. The Further, from the calculated projected area of the toner particle image, the circumference of a circle having the same area (the circumference of the circle having the same area as the toner particle projected area) is calculated. The average circularity is obtained by dividing the circumference of the circle having the same area as the toner particle projection area calculated in this way by the circumference of the toner particle projection image.

Measurement was performed under the following conditions using the above apparatus. The measurement results are shown in Table 6.
(A) Preparation of toner particle suspension 0.1 g of a surfactant (ELCLEAR (manufactured by Chugai Photonics Co., Ltd.)) is added to 20 g of water, and 0.04 g of a mother toner as a sample is added. The toner particles are suspended in water using a sonic disperser.
(B) Measurement conditions Measurement temperature 25 ° C
Measurement humidity 60%
Number of toner particles measured 5000 ± 2000

(3) Coexistence of coarse particles For coarse particles, the slurry after completion of solvent removal was observed at 200 times the transmission optical microscope. The observation results are shown in Table 6. In Table 6, × indicates that a large number of coarse particles of 30 μm or more are observed in the visual field, Δ indicates that one or two coarse particles of 30 μm or larger are observed by changing the visual field, and ○ indicates a visual field. In this case, coarse particles of 30 μm or more are not observed even when the diameter is changed.

  From Table 6, the mother toner particles of each color of Application Examples 1 to 4 using the colorant kneaded material obtained in the examples all have a good particle size distribution, and there is no mixing of coarse particles in the particle forming step. It can be seen that the toner has good toner properties. On the other hand, the mother toner particles of Application Examples 5 to 8 using each colorant kneaded product of the comparative example have a broad particle size distribution, and are mixed with coarse particles having coarse particles of the colorant as a core. It turns out that it is not preferable because it causes various problems when used.

It is a schematic plan view which shows the open roll type continuous kneader in one Embodiment of this invention.

Explanation of symbols

1 Open roll type continuous kneader

Claims (8)

  A raw material mixture containing a binder resin, a colorant, and water or a water-containing solvent is mixed in advance and then melt kneaded and dispersed using an open roll type continuous kneader having heating and cooling functions. A method for producing a colorant kneaded product.   The manufacturing method of the coloring agent kneaded material of Claim 1 in which the said raw material mixture has the said water or a water-containing solvent 5 mass% or more and 65 mass% or less with respect to the said coloring agent.   The method for producing a colorant kneaded product according to claim 1 or 2, wherein the raw material mixture contains the binder resin, the colorant, and a solvent.   The ratio of the colorant to the resin in the raw material mixture containing a part of the binder resin and the colorant is higher than the ratio of the colorant in the toner. A method for producing a colorant kneaded product. A first step of producing a colorant-containing resin liquid by dissolving or dispersing a mixture containing a binder resin mainly composed of a polyester resin having a carboxyl group and a colorant in an organic solvent, and containing the colorant A second step of producing a suspension of the colorant-containing fine particles (A) by suspending a resin liquid in an aqueous medium, and a method for producing a color toner for developing an electrostatic image, comprising:
The method for producing a color toner for developing an electrostatic charge image, wherein the mixture is the colorant kneaded product according to any one of claims 1 to 4. The second step is a step of suspending the colorant-containing resin liquid in water in the presence of a basic compound to produce a suspension of the colorant-containing fine particles (A). later,
A dispersion stabilizer is added to the suspension of the colorant-containing fine particles (A), and then an electrolyte is added to produce the combined fine particles (A) (B), and then the organic solvent is removed. The third step;
A fourth step of separating the combined body (B) from the aqueous medium and drying;
6. The method for producing a color toner for developing an electrostatic image according to claim 5, wherein:   The electrostatic charge according to claim 5 or 6, wherein the colorant-containing resin liquid is obtained by dissolving or dispersing a mixture containing the binder resin and the colorant in an organic solvent using a high-speed stirrer. A method for producing a color toner for image development. 8. The process according to claim 5, wherein the step of producing a suspension of the colorant-containing fine particles (A) by suspending the colorant-containing resin liquid in an aqueous medium is performed using a high-speed stirrer. A method for producing a color toner for developing an electrostatic charge image according to claim 1.

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