JP4761206B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

  The present invention relates to a method for producing a toner for developing an electrostatic charge image used for developing an electrostatic latent image on a latent image carrier in an image output device such as a copying machine, a printer, or a fax machine.

In image output devices such as electrophotographic copiers, printers, fax machines, etc., the resolution of printed images is improved, the gradation is improved, the amount of waste toner is reduced, and the energy consumption is reduced by lowering the fixing temperature. Due to demands for improving image characteristics in a full-color image, toner particles used for image formation use a polymerization method, an emulsification dispersion method, or the like instead of a pulverization method for producing small particle size particles by pulverization.
In the toner produced by suspension polymerization or the like of the monomer component, there are problems that the usable binder resin is limited and the particle size distribution of the formed toner particles becomes wide.

On the other hand, a solution suspension method in which particles are formed after emulsifying a mixture of a binder resin and a colorant has been proposed. In this method, a polyester resin having excellent low-temperature fixing characteristics is used as a binder resin. However, the dissolution suspension method has a problem that the particle size distribution of the obtained toner particles is wide.
In addition, a method has been proposed in which, after producing fine particles by dissolution suspension, a step of aggregating the fine particles and a step of heating and fusing the agglomerated fine particles to each other are proposed. There is a limit to narrowing the particle size distribution of the toner particles to be generated.

For these methods, binder resin such as polyester resin, wax, colorant and the like are dissolved or dispersed in an organic solvent, and the resulting colored resin solution is emulsified with submicron particles formed by phase inversion emulsification. There has been proposed a method for producing a toner through a coalescing step in which an aqueous electrolyte solution is added to a suspension to coalesce fine particles (see, for example, Patent Documents 1 and 2).
In this method, fine particles can be united at room temperature, so that a toner having a spherical shape and a sharp particle size distribution can be obtained.
JP 2003-122051 A JP 2004-198598 A

  The present invention adds an aqueous electrolyte solution to an emulsified suspension obtained by phase inversion emulsification of a composition containing a binder resin, a colorant, a wax, and an organic solvent, and adjusts the stirring speed to particles of a predetermined size. When toner particles are produced by growth, the colorant remains in the dispersion containing the aqueous medium without being encapsulated in the resin particles, or adheres to the surface of the resin particles in the filtrate in the washing step of the resin particles. Therefore, it is an object to solve the problem that toner particles having a desired color density cannot be obtained due to flow out of the toner, and to produce toner particles having excellent quality.

The present invention relates to a method for producing a toner for developing an electrostatic image, in which a colored resin solution obtained by dissolving or dispersing a binder resin, a colorant, and a wax in an organic solvent is phase-inverted and emulsified to prepare an emulsion suspension. The aqueous electrolyte solution is added and stirred to unite the dispersoids in the emulsified suspension. The binder resin is a cross-linked polyester resin having a first weight average molecular weight, and the first weight. Linear polyester resin having a second weight average molecular weight lower than the average molecular weight, and linear polyester resin having a third average molecular weight lower than the first weight average molecular weight and higher than the second weight average molecular weight is obtained by blending, the colorant third of the weight average molecular weight of the linear polyester resin and an electrostatic image developing toner formulated with a master consisting of colorants of the binder resin It is a method of manufacture.

As described above, by using a resin having a weight average molecular weight between a resin having a high weight average molecular weight and a resin having a low molecular weight between the two types of synthetic resins having different molecular weights constituting the binder resin as the colorant, and the colorant. The produced colorant-containing resin composition is combined with the dispersoid from the emulsion suspension formed by phase inversion emulsification to grow into particles of a predetermined size, so the affinity with the binder resin particles is good Thus, it is possible to produce a toner that is well encapsulated in the particles in the coalescing step and does not have a colorant outflow.
The master was prepared by subjecting the colorant and the linear polyester resin having the third weight average molecular weight to a melt-kneading dispersion treatment using an open roll type continuous kneader having heating and cooling functions. Therefore, a toner having good affinity with the binder resin particles, good encapsulation in the particles in the coalescing step, and no colorant outflow can be produced.

The second weight average molecular weight linear polyester resin has a weight average molecular weight of less than 5500, the first weight average molecular weight crosslinked polyester resin has a weight average molecular weight of 100,000 or more, The weight average molecular weight linear polyester resin has a molecular weight of 5500 to less than 100,000.
The mass ratio of the amount of the of the a colorant third weight average molecular weight linear polyester resin constituting the master is the method for producing a toner is 30 / 70-60 / 40.
As a result, a toner having a sharp particle size distribution, excellent characteristics, and good low-temperature fixability can be produced.

  The inventors have obtained dispersoids such as resin oil droplets, wax dispersoids and colorant dispersoids produced by phase inversion emulsification of a colored resin solution containing a binder resin, a colorant, a wax, and an organic solvent. A method of growing toner particles having a predetermined particle diameter by changing the emulsified state by adding an aqueous electrolyte solution and changing the shearing force applied to the fine particles by changing the stirring speed has been proposed. In this method, the colorant is not completely taken into the resin particles and the colorant may flow out into the aqueous medium. Furthermore, the molecular weight of the synthetic resin constituting the colorant master is between two types of synthetic resins having different weight average molecular weights constituting the binder resin, and between a synthetic resin having a large weight average molecular weight and a resin having a small weight average molecular weight. It has been found that by using a resin having a molecular weight, particles in which the colorant is encapsulated in the particle particles can be produced in the coalescing step.

The preparation process of the colorant master of the present invention will be described.
In the preparation process of the colorant master, a synthetic resin having a weight average molecular weight between a synthetic resin having a small weight average molecular weight and a synthetic resin having a large weight average molecular weight among the synthetic resins constituting the binder resin, a colorant, and water Or the raw material mixture which consists of a liquid medium containing at least any one of the organic solvent is knead | mixed using open roll type | mold continuous kneaders, such as a kneedex (made by Mitsui Mining).

The kneading is performed at a temperature not lower than the softening point of the colorant master resin to be kneaded and not higher than the thermal decomposition temperature. The raw material mixture preferably contains 5 parts by mass to 65 parts by mass of water or an organic solvent, or a liquid medium of these mixtures with respect to 100 parts by mass of the colorant.
By mixing 5 parts by mass to 65 parts by mass, preferably 10 parts by mass to 60 parts by mass of a liquid medium of water, an organic solvent, or a mixture thereof with respect to 100 parts by mass of the colorant, the fluidity of the raw material mixture In the kneading step, it is possible to avoid scattering of the raw material mixture, powder spillage, and powder flow, and efficiently perform melt kneading with an open roll type continuous kneader.

The open roll type continuous kneader includes a pair of cylindrical rolls, and each roll has a plurality of spiral grooves formed on the surface, and each roll is configured to rotate at an arbitrary number of rotations. And when both rolls rotate inside, the some groove | channel which has the spiral shape provided in the roll surface will push a raw material toward a kneaded material discharge part from a raw material supply part.
As a result, the raw material supplied from the raw material supply unit is melted and kneaded while being compressed and sheared, and transferred to the other end on the kneaded product discharge unit side.
The inside of the roll is hollow, and the surface temperature of the roll can be adjusted to a predetermined value by supplying a heat medium such as warm water, steam, or cooling water to the hollow portion.
In addition, a partition is provided at a location where the heat medium is introduced inside the roll, and the roll temperature can be partially changed.

For example, the rotational speed of one roll is set to be higher than the rotational speed of the other, and the surface temperature of the kneaded material wound around the roll is 110 ° C. at the temperature of one end on the raw material supply side, The roll temperature is adjusted so that it gradually decreases as it goes and reaches 88 ° C. on the kneaded product discharge part side. This is set so that efficient compression and shearing can be performed by suppressing a decrease in viscosity due to heat generated by the supplied raw material being compressed and sheared.
Moreover, by setting in this way, it can transfer to the kneaded material discharge | emission part side in the state which made the kneading | mixing raw material adhere to the spiral groove of the roll with many rotation speeds.
The raw material supply unit can be configured such that the raw material is quantitatively supplied by a screw feeder or the like, and the kneaded product discharge unit collects the melt-dispersed kneaded material adhering to the roll.

In the open roll type continuous kneader configured as described above, the granulated product supplied to the raw material supply unit is heated by the surface temperature of both rolls. Next, a rapid compressive force and shearing force are applied in the gap between the two rolls, and heat is generated to melt.
Both rolls are repeatedly subjected to compressive shear and kneaded to form a melt-dispersed kneaded product, which is discharged as a kneaded chip at the kneaded product discharge unit.

  Further, the rotational speed (F) of the front roll and the rotational speed (R) of the rear roll are F> R, and it is preferable to increase the rotational speed of the front roll, and the rotational speed ratio (R / F) is It is preferable that it is 0.6-0.9. When kneaded under such conditions, the kneaded material is wound around the front roll, and the kneaded material is not wound around the back roll, so that the material can be easily transferred and recovered in the kneaded material discharge section.

In addition, in the production of the toner of the present invention, the open roll type continuous kneader includes a synthetic resin having a large weight average molecular weight among the two kinds of synthetic resins having different weight average molecular weights constituting the binder resin together with the colorant. A colored master is produced by supplying a resin having a molecular weight between the resin having a small weight average molecular weight.
By preparing a coloring master using a linear polyester resin having a molecular weight between a cross-linked polyester resin having a large molecular weight and a linear polyester resin having a low molecular weight constituting the binder resin, In the production process of the toner particles, the colorant is well dispersed in the binder resin, and a toner excellent in encapsulation in the resin particles can be obtained.

Moreover, the molecular weight of the polyester resin having a small weight average molecular weight is less than 5500, the molecular weight of the polyester resin having a large weight average molecular weight is 100,000 or more, and the molecular weight of the polyester resin for preparing the colorant master is 5500 to less than 100,000. Is preferred.
The resin constituting the binder is selected from the viewpoint of low-temperature fixability and the like, but when the viscosity is high, uniform kneading becomes difficult, and when the viscosity is low, shearing force is applied. Without sufficient kneading.
Therefore, after preparing a colorant master in which a colorant is kneaded using a linear polyester resin having a molecular weight between a resin having a high molecular weight and a resin having a low molecular weight, the binder is prepared. It is considered that the fine dispersion of the colorant in the binder resin can be improved by kneading with the resin.

Hereinafter, the production process of the toner of the present invention will be described.
First step: Colored resin solution preparation step A step of producing a colored resin solution by dissolving or dispersing a binder resin mainly composed of a polyester resin, a colorant and a wax in an organic solvent, and then adding an emulsifier. It is.
Second step: Phase inversion emulsification step After adding the basic compound, water is added to the colored resin solution to perform phase inversion emulsification to obtain an emulsified suspension.
Third step: coalescence step An aqueous electrolyte solution is added to the prepared emulsification suspension to coalesce fine particles such as resin oil droplets, wax dispersoid, and colorant dispersoid in the emulsion suspension. This is a step of stopping coalescence after performing the step of generating particles and forming particles at least three times. Note that the first coalescence step performs precipitation of fine particles and coalescence of the precipitated fine particles, and can also be referred to as a precipitation coalescence step.
Fourth Step: Separation and Drying Step In this step, after removing the organic solvent under reduced pressure, the coalesced particles are separated from the aqueous medium, washed and dried to form toner base particles.

  First, the colored resin solution preparation step, which is the first step, will be described in detail. In the colored resin solution preparation step, first, a binder resin mainly composed of a self-dispersing synthetic resin dispersed in an aqueous medium such as a polyester resin in an organic solvent, a coloring agent, and a wax are introduced, dissolved or dissolved. Disperse and finely disperse or dissolve below the toner particle size.

  As described above, the coloring agent is prepared by mastering a synthetic resin having a lower molecular weight than a synthetic resin having a high molecular weight constituting the binder resin and a higher molecular weight than a synthetic resin having a small molecular weight constituting the binder resin. As a raw material, a colorant master produced by kneading with a colorant is used.

In the colored resin solution preparation step, Desper (manufactured by Asada Iron Works), T.W. K. A high-speed stirrer such as a homomixer (Primix) can be used. The blade tip speed at this time is preferably 4 to 30 m / s, and more preferably 8 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 of the colorant in the binder resin solution can be achieved. That is, the coloring agent finely dispersed in advance can be held in the colored 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 colored resin solution is insufficient, which is not preferable. On the other hand, when it is higher than 30 m / s, heat generation due to shearing is increased, and it is not preferable because uniform stirring becomes difficult in combination with volatilization of the solvent. Moreover, the temperature in the case of melt | dissolving or disperse | distributing has the preferable range of 20-60 degreeC, and the range of 30-50 degreeC is more preferable.

  As an organic solvent, the thing whose solubility with respect to water in 25 degreeC is 0.1-30 mass% is preferable, and what is 0.1-25 mass% is more preferable. The boiling point at normal pressure is preferably lower than the boiling point of water. Examples of such an organic solvent include ketones such as methyl ethyl ketone and methyl isopropyl ketone, and esters such as ethyl acetate and isopropyl acetate. 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. In addition, the organic solvent is preferably one having a low boiling point because it dissolves or disperses the polyester resin and is easy to remove the solvent in a later step. Here, as the organic solvent for dissolving the polyester resin, it is preferable to use methyl ethyl ketone and ethyl acetate, which are excellent in solubility and dispersibility. In particular, it is more preferable to use methyl ethyl ketone.

Moreover, it is preferable to add an emulsifier in the preparation process of the colored resin solution.
In order for the emulsifier to function in the coalescing step, it is necessary to have a characteristic capable of maintaining dispersion stability even in the presence of an electrolyte added later. Examples of emulsifiers having such properties include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene Nonionic emulsifiers such as oxyethylene sorbitan fatty acid esters or various pluronics, alkyl sulfate ester type, alkyl sulfonate type anionic emulsifiers, and quaternary ammonium salt type cationic emulsifiers is there. Moreover, an alkylbenzene sulfonate type emulsifier and a linear alkyl benzene sulfonic acid type emulsifier can be mentioned.
The above-mentioned emulsifiers may be used alone or in combination of two or more. That is, in the production method of the present invention, it is possible to prevent non-uniform coalescence by adding an electrolyte in the presence of an emulsifier. Thereby, a preferable particle size distribution is obtained and an improvement in yield is achieved.

  Moreover, 0.1-3.0 mass% is preferable with respect to solid content, and, as for the quantity of the emulsifier to use, it is more preferable that it is 0.3-2.0 mass%, and 0.3-1. It is especially preferable that it is 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.

  Next, in the phase inversion emulsification step of the second step, after adding the basic compound, the colored resin-containing composition is suspended or emulsified by adding water to obtain an emulsified suspension. Here, it is preferable to gradually add water to the colored resin solution obtained by neutralizing the carboxyl group of the polyester resin with a basic compound. By neutralizing the carboxyl group, the hydrophilicity of the functional group portion is improved and the affinity with water is improved.

  The dropped water is hydrated to the functional group portion and dissolved or finely dispersed together with the stirring effect. On the other hand, the binder resin has strong acid-base interaction through an aqueous medium, and the viscosity increases with the addition of water. When a certain amount of water is added, there is a point that the viscosity decreases, which is called a so-called phase inversion point. Until just before this, the viscosity increases and reaches a maximum value. The increase in viscosity correlates with the addition amount of the basic compound, and the increase in viscosity increases as the addition amount increases.

  On the other hand, in the present invention, the amount of the basic compound affects not only the phase inversion emulsification step of the second step but also the uniformity and speed at the time of coalescence particle generation in the coalescence step of the third step described later. The basic compound is preferably in the range of 1 to 3 equivalents relative to the carboxyl group of the polyester resin. Moreover, the range of 1-2 equivalent is still more preferable. Thus, by adding in excess of the amount required to neutralize all of the carboxyl groups of the polyester resin, it is possible to prevent the formation of irregularly shaped particles in the coalescence process, and the particle size distribution can be reduced. It can be a narrow range.

  However, if the total amount of the basic compound is added before emulsification, the viscosity increases during emulsification, and non-emulsified foreign matter is generated due to uneven stirring, which is mixed in the finally obtained toner and adversely affects the development characteristics. Will be affected. Therefore, the amount of the basic compound is preferably 0.6 to 1.2 equivalents. When the amount is less than 0.6 equivalent, the dispersion of the colorant or the additive such as wax becomes non-uniform during emulsification or an unemulsified product is generated. On the other hand, when the amount is more than 1.2 equivalents, an effect due to an increase in viscosity is observed, which is not preferable.

The ratio of the organic solvent / organic solvent + water after completion of the phase inversion emulsification step is preferably in the range of 20 to 35% by mass, and more preferably in the range of 23 to 30% by mass. As described above, the amount of water up to the phase inversion point decreases as the amount of organic solvent in the colored resin solution preparation step decreases, and increases as the amount of basic compound increases.
Since the viscosity of the emulsified suspension may be high at the phase inversion point, and the colored resin solution may not be completely finely dispersed in the aqueous medium, it is preferable to add more water, and the amount of added water The total water used up to the phase inversion point is preferably in the range of 50 to 80% by mass.

The polyester resin used in the present invention preferably has an acid value of 3 to 30 KOHmg / g, more preferably 5 to 20 KOHmg / g.
This is not preferred if the acid value of the polyester resin is less than 3, since the production of an emulsified suspension in which the polyester resin and the organic solvent are emulsified or suspended in water is not carried out smoothly and coarse particles are generated.
On the other hand, if the acid value of the polyester resin is greater than 30, the charge amount in the toner use environment is not stable, which is not preferable. The polyester resin having an acid value of 3 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 can be stably dispersed or dissolved.

  Examples of the basic compound for neutralization include inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonia, and organic bases such as diethylamine, triethylamine, and isopropylamine. In particular, an aqueous solution of an inorganic base such as ammonia, sodium hydroxide, or potassium hydroxide is preferred.

  In the emulsified suspension produced by the above method, the colored resin solution exists in the state of being emulsified or suspended in an aqueous medium as resin oil droplets, a colorant dispersoid, a wax and the like. The state varies depending on the type and amount of organic solvent used, the acid value of the polyester resin, the amount of basic compound used, the stirring conditions, and the like, but it is preferably emulsified or suspended as fine oil droplets of 1 μm or less. Such a state is preferable because the stability of the emulsified suspension, the stability of coalescence in the subsequent steps, the particle size distribution of the coalesced particles, and the like are improved.

Next, the unification process which is the 3rd process is explained. By adding an electrolyte in the presence of an emulsifier, coalesced particles that are a unitary of fine particles can be produced.
The coalescing step includes a step of depositing fine particles of the colored resin solution by dropping the electrolyte aqueous solution in the presence of an emulsifier and a coalescing step in which the associated particles grow thereafter.
First, fine particles formed from individual dispersoids such as resin oil droplets, colorant dispersoids, or wax dispersoids, and fine particles in which these fine particles are combined are precipitated, and the size ranges from 0.01 μm to 0.00. The size is about 4 μm.
Next, coalesced particles are obtained by coalescing the fine particles.
In the coalescing process, by adding an electrolyte aqueous solution to the emulsified suspension, the fine oil droplets of the emulsified or suspended colored resin solution are salted out or destabilized, and a plurality of fine particles are integrated. As a result, the coalescence proceeds and the desired particle size can be obtained.

  In addition, the addition of the electrolyte aqueous solution not only brings together the fine particles containing the colorant, but also causes the polyester resin dissolved in the aqueous medium to salt out or destabilize to precipitate the fine particles of the polyester resin. The coalesced particles can be obtained by adhering to the surface of the fine particles containing the agent or the coalesced particles already coalesced.

Examples of the electrolyte used here include 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. Water-soluble salts such as sodium hydrogen carbonate, ammonium hydrogen carbonate, and sodium acetate can be used. These electrolytes may be used alone or as a mixture of two or more kinds of substances. Of these, monovalent cation sulfates and carbonates such as sodium sulfate and ammonium sulfate are preferred for promoting uniform coalescence.
In addition, the resulting coalesced particles are swollen by the solvent, and the hydration state of the particles is unstable due to the addition of an electrolyte. Therefore, the particles are collided with each other by stirring with low shear force. It is preferable to proceed one.

In order to promote uniform coalescence, agitation conditions for coalescence are important. For example, an anchor wing, a turbine wing, a Faudler wing, a full zone wing, a Max blend wing (registered trademark), and a meniscus wing are used. Among them, it is preferable to use a large blade having excellent uniform mixing characteristics even at a low rotation, such as Max Blend blade (registered trademark) or full zone blade. 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, it is not preferable because fine particles remain. 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, since coalescence proceeds preferentially from fine particles in the coalescence process, generation of ultrafine particles is small, and a narrow particle size distribution is achieved, so that an improvement in yield can be achieved.
That is, in the colored resin solution preparation step and the phase inversion emulsification step, it is preferable to stir with a high speed stirrer such as Desper (manufactured by Asada Iron Works), and in the coalescing step, a large blade capable of uniform mixing at low speed is suitable. It is preferable to carry out the coalescing step by transferring the emulsified suspension obtained in the phase inversion emulsification step to another container attached to the large blade.

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 1-6 mass%. When the amount of the electrolyte is less than 0.5% by mass, coalescence does not proceed sufficiently.
On the other hand, when the amount of the electrolyte is more than 15% by mass, the coalescence becomes non-uniform, and aggregates and coarse particles are generated, resulting in a decrease in yield.
Moreover, it is not preferable that the electrolyte concentration is high because aggregates are likely to be generated at the time of precipitation of the dissolved polyester resin due to salting out in the initial coalescence. On the other hand, when the electrolyte concentration is low, a large amount of electrolyte is required for salting out and coalescence, and fine particles are likely to remain, which is not preferable.

That is, at the time of precipitation at the beginning of coalescence, since the size is small and the specific surface area is large, it is easily affected by the concentration unevenness in the vicinity of the added electrolyte aqueous solution, and aggregation may occur due to the concentration unevenness. For this reason, it is preferable that the concentration is set to be low so that the concentration unevenness of the electrolyte does not occur at the initial stage of fine particles.
In addition, when the particle size is grown to exceed 3 μm, it is preferable to control the particle growth rate by increasing the electrolyte concentration and adjusting the amount of the electrolyte aqueous solution added accordingly. When a large amount of low-concentration electrolyte aqueous solution is added, the amount of the added solution increases, the organic solvent ratio decreases, and coalescence does not progress and fine particles remain easily.

In the present invention, a colored resin solution containing a binder resin, a colorant, a wax, and an organic solvent is formed by phase-inversion emulsification to form an emulsion suspension, and particles of a predetermined size are grown from the emulsion suspension. It is. For particle growth, an electrolyte is added to the emulsified suspension and stirred to provide three or more steps including a step of precipitation and coalescence of fine particles. The particle growth rate is made slower than the particle growth rate in any of the coalescing steps.
The particle growth rate in the coalescence process can be adjusted by a method such as reducing the electrolytic mass contained in the aqueous electrolyte solution added in the coalescence process or reducing the electrolyte aqueous solution itself.

When a toner having a volume average particle size of about 5 to 7 μm is produced, the electrolyte concentration is preferably in the range of 2 to 4% by mass at the stage where the particle size of the fine particles in the initial coalescence grows to 3 μm. Further, when the particle size is further increased beyond 3 μm, a concentration in the range of more than 4% by mass and 6% by mass is preferable.
When a toner having a volume average particle diameter of about 5 to 7 μm is produced, the electrolyte concentration is in the range of 2 to 4% by mass with respect to the solid content at the stage where the particle diameter of the fine particles in the initial coalescence grows to 3 μm. It is preferable to add 1 to 3% by mass of electrolytic mass. Further, when the particle size is further grown to exceed 3 μm, a concentration in the range of more than 4% by mass to 6% by mass is preferable. It is preferable to confirm the particle growth rate and to reduce the electrolytic mass with respect to the solid content while adjusting the amount of solution as the latter stage of the coalescence process.

In particular, it is preferable to set the particle growth rate after dropping of the aqueous electrolyte solution in the final coalescence step to a range of 0.1 to 0.5 μm / 10 min on the basis of the volume average particle size.
The particle size in the present invention is a volume average particle size measured by measurement with a multisizer type II (aperture tube diameter: 100 μm) manufactured by Beckman Coulter.

When adding the aqueous electrolyte solution in each coalescence step, it is preferable to increase the stirring speed in order to mix the electrolyte uniformly and quickly in the system. It is preferable because generation of aggregates due to dropping of the aqueous electrolyte solution can be suppressed. 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, for example, coalescence particles can be produced by coalescence under a low temperature condition of 20 to 40 ° C.

  In the coalescence, the colored resin fine particles swollen by the organic solvent are stirred at a predetermined rotation speed so that the colored resin fine particles collide with each other and are fused to grow particles. Therefore, the colored resin united by providing an aging period in which a high shear force is given by stirring at a higher speed than the stirring speed at which the coalescence progresses between the coalescence process in the previous stage and the coalescence process in the next stage. Fine particles can be aged to increase the circularity of the combined particles.

  In addition, the particle growth can be expressed by creating a particle growth curve plotted from the time and the particle size in order to maintain a substantially constant growth rate under a certain condition. As a result, the arrival time of the target particle diameter can be estimated from the curve. The coalescence is preferably stopped by adding water.

In addition, the coalesced particles obtained in the coalescing step are swelled by encapsulating an organic solvent in an aqueous medium, and therefore easily aggregate when placed at a high temperature condition or left standing.
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. In removing the solvent, an antifoaming agent is preferably added. The antifoaming agent is preferably in the form of a silicone emulsion. Examples of the silicone-based antifoaming agent include BY22-517, SH5503, SM5572F, BY28-503 (manufactured by Toray Dowco Ichining Silicone), KM75, KM89, KM98, KS604, KS538 (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. is there. Especially, BY22-517 is preferable as a thing with little influence on a physical property and a high defoaming effect. The amount of the antifoaming agent is preferably 30 to 100 ppm with respect to the solid content.

  The toner particles produced by the production method of the present invention are characterized in that a colorant, wax, or the like is included in a binder resin, and the colorant, wax, etc. are observed by observation with a transmission electron microscope or the like. It can be confirmed that the particles are contained in the particles and are almost uniformly dispersed.

Further, the shape of the coalesced particles obtained in the coalescing step is determined by a particle image analyzer (flow type particle image analyzer FPIA-1000 manufactured by Sysmex), and the circularity corresponds to the projected area of the observed particle image. The average value of the numerical value represented by the ratio of the circumference of the circle to be observed and the circumference of the observed projected image of the particle is the average circularity.
The toner particles obtained by the method of the present invention have a substantially spherical or spherical shape with an average circularity of 0.95 or more to 0.97 or more, and powder flowability and transfer efficiency are improved.

  In the coalescence process, the coalesced particles grown to the target particle diameter include the coalesced particles after adding water to the aqueous medium containing the coalesced particles and stopping coalescence in the separation and drying process. The organic solvent used can be removed from the aqueous medium and dried.

  In the separation and drying step, the colored resin particles are separated, washed and dehydrated to obtain a colored resin fine particle cake. Separation and dehydration from the aqueous medium can be performed by a centrifugal separator, or a separation means such as a filter press or a belt filter. The washing can be performed by stirring and dispersing the obtained colored resin fine particle cake again in water and further dehydrating. Next, toner base particles can be obtained by drying the particles. Further, when a dispersion stabilizer is added in the previous step, it is preferable to wash more sufficiently.

  The obtained hydrous coalesced particles are subsequently dried to form a powder. Drying is fluidized bed type drying such as ribocorn type dryer (Okawara Seisakusho), mixing vacuum dryer such as Nauta mixer (Hosokawa Micron), fluidized bed dryer (Okawara Seisakusho), vibration fluidized bed dryer (Central Chemical). It is dried with a machine.

  As for the particle size distribution of the toner, it is possible to obtain a toner having a 50% volume particle size / 50% number particle size of 1.25 or less as measured by a multisizer type II (aperture tube diameter: 100 μm) manufactured by Beckman Coulter. it can. When it is 1.25 or less, a good image excellent in gradation can be obtained.

  The volume average particle diameter of the toner is preferably 3 to 8 μm, and the use of a toner having a small particle diameter not only improves resolution and gradation, but also forms a printed image. The thickness of the toner layer is reduced, the amount of heat required for fixing can be reduced, and at the same time, the toner consumption can be reduced.

The polyester resin used in the present invention will be described. The polyester resin 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 dibasic acid or a derivative thereof, a divalent alcohol, and a polyvalent compound as a cross-linking agent. In particular, it is preferable to produce by reacting a dibasic 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 dibasic acid with a divalent alcohol. In particular, it is preferable to produce by reacting a dibasic acid with a divalent aliphatic alcohol.

  Acid components used in the production of cross-linked polyester resins and linear polyester resins include phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, maleic acid, maleic anhydride, fumaric acid, itacone Examples thereof include dicarboxylic acids such as acid, citraconic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, azelaic acid, sebacic acid, and derivatives or esterified products thereof.

  Examples of the divalent aliphatic alcohol component include 1,4-cyclohexanedimethanol, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, neopentyl glycol, butanediol, and pentanediol. Hexanediol, 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, etc. Diols are mentioned.

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 the polyvalent epoxy compound 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 of vinyl compound having epoxy group, or copolymer, epoxidized resorcinol-acetone condensate, partial Epoxidized 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, as examples of bisphenol A type epoxy resin, Epicron 850, Epicron 1050, Epicron 2055, Epicron 3050, etc. manufactured by Dainippon Ink & Chemicals, Inc., Epicron 830 manufactured by Dainippon Ink & Chemicals, Inc. as examples of bisphenol F type epoxy resins, Epicron 520 and the like are examples of orthocresol novolak type epoxy resins, Epicron N-660, N-665, N-667, N-670, N-673, N-680, N-690, manufactured by Dainippon Ink and Chemicals, Inc. Examples of phenol novolac type epoxy resins such as N-695 include Epicron N-740, N-770, N-775, N-865 and the like manufactured by Dainippon Ink and Chemicals, Inc. 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 monoepoxy compounds that can be used simultaneously 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, and the like. 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.
A specific example is neodecanoic acid glycidyl ester (Shell Japan Cardura E).

  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 in this case can be 2 to 24 hours at 150 to 300 ° C.

  As a 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.

  The use ratio of the cross-linked polyester resin and the linear polyester resin used in the present invention is (mass of cross-linked polyester resin) / (mass of linear polyester resin) = 5 / 95-60 / 40. Can do. Moreover, it is good also as 10 / 90-40 / 60 or 20 / 80-40 / 60. By adjusting the ratio of the cross-linked polyester resin, high temperature offset resistance, melt viscosity (T1 / 2 temperature), low temperature fixability and the like can be adjusted.

The glass transition temperature (Tg) of the cross-linked polyester resin is preferably 40 to 85 ° C, and particularly preferably 40 to 75 ° C. When the glass transition temperature (Tg) is lower than 40 ° C., a blocking phenomenon (thermal aggregation) tends to occur when the toner is stored, transported, or exposed to a high temperature inside the image forming apparatus. 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 35 to 70 ° C, and particularly preferably 35 to 65 ° C. When the glass transition temperature (Tg) is lower than 35 ° C., a blocking phenomenon, that is, thermal aggregation tends to occur when the toner is stored, transported, or exposed to a high temperature inside the image forming apparatus. 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.

  In addition, the softening point of the cross-linked polyester resin is preferably 150 ° C. or higher, and particularly preferably 150 ° C. to 220 ° C. Here, the softening point of the cross-linked polyester resin is more preferably 150 ° C. to 200 ° C., and particularly preferably 150 ° C. to 190 ° C. When the softening point is less than 150 ° C., the toner tends to cause an aggregation phenomenon, which may hinder image formation. On the other hand, if it exceeds 220 ° C., the fixability tends to deteriorate. Moreover, it is preferable that the softening point of a linear polyester resin is 85 degreeC or more, and it is preferable that it is 85 to 130 degreeC especially. Here, the softening point of the linear polyester resin is more preferably 85 ° C to 120 ° C, and particularly preferably 85 ° C to 110 ° C. Similar to the cross-linked polyester resin, when the softening point is less than 85 ° C., the glass transition temperature is lowered, and the toner tends to cause an aggregation phenomenon, and when it exceeds 130 ° C., the fixability is likely to deteriorate. .

  Moreover, it is preferable that the softening point of the mixture of cross-linked polyester resin and linear polyester resin is 100 ° C to 150 ° C. It is more preferable to set it as 120 to 140 degreeC. When the softening point is less than 100 ° C., the toner tends to cause an aggregation phenomenon, and when it exceeds 150 ° C., the fixability tends to deteriorate.

The softening point of the polyester resin in the present invention is a T1 / 2 temperature measured using a constant load extrusion capillary type rheometer (Shimadzu Corporation flow tester CFT-500). The measurement conditions were as follows: piston cross-sectional area 1 cm ² , cylinder pressure 0.98 MPa, die hole length 1 mm, die hole diameter 1 mm, measurement start temperature 50 ° C., heating rate 6 ° C./min, sample mass 1.5 g. It was.
In addition, the glass transition point (Tg) was measured by using a differential scanning calorimeter (DSC-60A, manufactured by Shimadzu Corporation), putting a 20 mg sample in an aluminum crimp container, and heating at 180 ° C. at a temperature rising rate of 10 ° C./min. The temperature was cooled to 25 ° C. from 180 ° C. at a rate of temperature decrease of 10 ° C./min, and again raised to 180 ° C. at a rate of temperature increase of 10 ° C./min. The displacing temperature was taken as the glass transition point.

In the production method of the present invention, waxes that can be introduced in the colored resin solution preparation step include hydrocarbon waxes such as polypropylene wax, polyethylene wax, and Fischer-Tropsch wax, synthetic ester waxes, carnauba wax, and rice. Mention may be made of waxes selected from natural ester waxes such as waxes. 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 suitable. Examples of the synthetic ester wax include WEP-5 and WEP-7 (manufactured by NOF Corporation).
In the method of the present invention, a sufficient amount of wax required for the toner can be contained, but 1 to 40% by mass is preferably contained in the toner particles.

The colored resin solution can be prepared by mixing a charge control agent. As the positively chargeable charge control agent, a nigrosine compound, a quaternary ammonium compound, an onium compound, a triphenylmethane compound, or the like can be used. In addition, basic group-containing compounds such as amino groups, imino groups, and N-heterocycles such as tertiary amino group-containing styrene acrylic resins can be used in combination with the nigrosine compound as a positively chargeable charge control agent. Further, a small amount of a negative charge control agent such as an azo dye metal complex or a salicylic acid derivative metal complex salt can 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, etc. 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 in the toner particles. It is especially preferable that it is 0.1-6 mass%.

  Examples of colorants that can be added in the colored resin solution preparation step include carbon black, C.I. I. Pigment Black 11 and other iron oxide pigments, C.I. I. Examples thereof include iron-titanium complex oxide pigments such as Pigment Black 12, or carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black.

  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. Among these, C.I. I. Pigment Blue 15: 3, 15, 16, 60 is preferable. I. Pigment Blue 15: 3, 60 is more preferable.

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, 9.4, 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. Among these, C.I. I. Pigment Yellow 17, 74, 93, 97, 110, 15.5 and 180 are preferred. I. Pigment Yellow 74, 93, 97, 180 is more preferable. I. Pigment Yellow 93, 97, and 180 are more preferable.

  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, 112311, 4, 115, 122, 123, 133, 144, 146, 147, 149 , 150, 151, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 184, 185, 187, 188, 189, 190, 193, 194, 202, 208, 209, 214 , 216, 220, 221 24,242,243,243: 1,245,246,247, and the like. Among these, C.I. I. PigmentRed 48: 1, 48: 2, 48: 3, 48: 4, 53: 1, 57: 1, 122, 184 and 209 are preferred. I. Pigment Red 57: 1, 122, 184 and 209 are more preferable.

  The content of the colorant is preferably 1 to 20% by mass in the toner particles, more preferably 2 to 18% by mass, and still more preferably 2 to 15% by mass. These colorants can be used alone or in combination of two or more.

The toner particles produced by the method of the present invention can be adjusted in fluidity, chargeability, etc. by adding fine particles such as silica and titania, or those subjected to hydrophobizing treatment as external additives. .
The obtained toner particles can be used as a one-component toner, but can also be used as a two-component toner by mixing a carrier.

Example 1
Synthesis of Resin 1 (Crosslinked Polyester Resin) In a 50 liter reaction kettle, raw materials such as an acid, an alcohol component and a catalyst having the following composition were put and reacted at 240 ° C. for 12 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 the softening point based on ASTM E28-517, and the reaction was terminated when the softening point reached 160 ° C.
Terephthalic acid 3.9 parts by mass Isophthalic acid 9.06 parts by mass Ethylene glycol 2.54 parts by mass Neopentyl glycol 4.26 parts by mass Tetrabutyl titanate 0.1 parts by mass Epicron 830 0.3 parts by mass (Dainippon Ink and Chemicals, Inc. Bisphenol F type epoxy resin, epoxy equivalent 170 (g / eq)
Cardura E 0.1 parts by mass (Shell Japan alkyl glycidyl ester) epoxy equivalent 250 (g / eq)

The obtained polymer was a colorless solid, and had an acid value of 11.0, a glass transition temperature (Tg) of 60 ° C., and a softening point (T1 / 2) of 178 ° C.
In addition, the weight average molecular weight was used in combination with TOS-GEL G5000HXL / G4000HXL / G3000HXL / G2000HXL manufactured by Tosoh as a separation column using a GPC measuring apparatus (HLC-8120GPC manufactured by Tosoh), column temperature: 40 ° C., solvent: tetrahydrofuran, solvent The molecular weight was determined by measuring at a concentration of 0.5% by mass, filter: 0.2 μm, flow rate: 1 ml / min, and conversion using standard polystyrene. The weight average molecular weight was 250,000.

Synthesis of Resin 2 (Linear Polyester Resin) In a 50 liter reaction kettle, raw materials such as acid, alcohol components and catalyst having the following composition were placed and reacted at 210 ° C. for 12 hours under a normal pressure nitrogen stream. It was. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point based on ASTM E28-517, and the reaction was terminated when the softening point reached 95 ° C.
Terephthalic acid 7.97 parts by mass Isophthalic acid 5.31 parts by mass Ethylene glycol 2.86 parts by mass Neopentyl glycol 4.8 parts by mass Tetrabutyl titanate 0.1 parts by mass

The obtained polymer was a colorless solid having an acid value of 10.0, a glass transition temperature (Tg) of 55 ° C., and a softening point (T1 / 2) of 107 ° C.
Further, when the molecular weight was measured in the same manner as the measurement of the molecular weight of Resin 1, it was a weight average molecular weight of 7740.

Synthesis of Resin 3 (Linear Polyester Resin) In a 50 liter reaction kettle, raw materials such as acid, alcohol component and catalyst having the following composition were placed and reacted at 210 ° C. for 12 hours under a normal pressure nitrogen stream. It was. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point according to ASTM E28-517, and the reaction was terminated when the softening point reached 87 ° C.
Terephthalic acid 5.31 parts by mass Isophthalic acid 7.97 parts by mass Ethylene glycol 2.6 parts by mass Neopentyl glycol 4.37 parts by mass Tetrabutyl titanate 0.1 parts by mass

The obtained polymer was a colorless solid, and had an acid value of 8.5, a glass transition temperature (Tg) of 46 ° C, and a softening point (T1 / 2) of 95 ° C.
Further, when the molecular weight was measured in the same manner as the measurement of the molecular weight of Resin 1, it was a weight average molecular weight of 5200.

Synthesis of Resin 4 (Linear Polyester Resin) In a 50 liter reaction kettle, raw materials such as acid, alcohol components and catalyst having the following composition were placed and reacted at 210 ° C. for 12 hours under a normal pressure nitrogen stream. It was. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point based on ASTM E28-517, and the reaction was terminated when the softening point reached 82 ° C.
Terephthalic acid 5.31 parts by mass Isophthalic acid 7.97 parts by mass Ethylene glycol 2.6 parts by mass Neopentyl glycol 4.37 parts by mass Tetrabutyl titanate 0.1 parts by mass

The obtained polymer was a colorless solid, and had an acid value of 7.5, a glass transition temperature (Tg) of 40 ° C., and a softening point (T1 / 2) of 90 ° C.
Further, when the molecular weight was measured in the same manner as the measurement of the molecular weight of the resin 1, the weight average molecular weight was 4000.

Synthesis of Resin 5 (Linear Polyester Resin) In a 50 liter reaction kettle, raw materials such as acid, alcohol component and catalyst having the following composition were placed and reacted at 210 ° C. for 12 hours under a normal pressure nitrogen stream. It was. Thereafter, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point based on ASTM E28-517, and the reaction was terminated when the softening point reached 82 ° C.
Terephthalic acid 5.31 parts by mass Isophthalic acid 7.97 parts by mass Ethylene glycol 2.6 parts by mass Neopentyl glycol 4.37 parts by mass Tetrabutyl titanate 0.1 parts by mass

The obtained polymer was a colorless solid having an acid value of 9.0, a glass transition temperature (Tg) of 48 ° C, and a softening point (T1 / 2) of 97 ° C.
Further, when the molecular weight was measured in the same manner as the measurement of the molecular weight of the resin 1, it was 5450 in weight average molecular weight.

Preparation of wax master dispersion 1 30 parts by weight of carnauba wax (carnauba wax 1 manufactured by Hiroyuki Kato), 70 parts by weight of resin 2 which is a linear polyester resin prepared earlier and 150 parts by weight of methyl ethyl ketone Then, the mixture was refined with a star mill LMZ-10 (manufactured by Ashizawa Finetech) to prepare a wax master dispersion 1 having a solid content of 40% by mass. This composition is Resin 2 / Wax / Methyl ethyl ketone = 28/12/60.

Preparation of Colorant Master Chip 1C Cyan pigment (Dai Nippon Ink Chemical Co., Ltd. Cyan Pigment: Ket Blue111 CIPigment B-15: 3) 2000 parts by mass and linear polyester resin 2 2000 parts by mass, ST / AO stirring blade Was added to a 20 L Henschel mixer (made by Mitsui Mining Co., Ltd.) and stirred at 698 min ⁻¹ for 2 minutes to obtain a mixture. Using the open roll continuous extrusion kneader set at a kneading part 93 ° C. and a cooling part 21 ° C. (Mitsui Mine Needex MOS140-800), the front side clearance is 75 rotations, the rear side rolls 60 rotation speed, and the entrance side clearance. The colorant master chip 1C was prepared by melt-kneading at 0.1 mm, outlet-side clearance 0.3 mm, and discharge rate 5.0-5.5 kg / h.

  The obtained master chip was diluted with methyl ethyl ketone, and the finely dispersed state of the colorant and the presence / absence of coarse particles were observed with a 400 × optical microscope. As a result, there were no coarse particles and the particles were uniformly finely dispersed.

Preparation of Colored Resin Solution 1 12.5 parts by weight of wax master dispersion 1, 4.2 parts by weight of colorant master chip 1C, 10.56 parts by weight of resin 1, 10.24 parts by weight of resin 3, and organic solvent 8.65 parts by mass of methyl ethyl ketone was added, the temperature was kept at 40 to 45 ° C., and the mixture was mixed for 2 hours at a stirring speed of 777 min ⁻¹ with a stirrer (Desper blade diameter 230 mm, manufactured by Asada Iron Works), dissolved and dispersed Went.
The resulting mixture was further added methyl ethyl ketone, the solid content was adjusted to 65% by mass, and 0.22 parts by mass of dodecylbenzenesulfonic acid-based emulsifier (Daiichi Kogyo Seiyaku Neogen SC-F) was added as an emulsifier. A colored resin solution 1 containing a cyan pigment was prepared by dissolution and dispersion.

Transfer emulsification step 46.15 parts by weight (solid content 30 parts by weight) of the colored resin solution 1 was charged in a cylindrical container equipped with a stirrer (Desper made by Asada Iron Works) having a stirring blade with a blade diameter of 230 mm, and then a base As a functional compound, 5 parts by mass of 1N ammonia water was added, and after sufficiently stirring at 777 min ⁻¹ , the temperature was adjusted to 35 ° C.
Subsequently, the stirring speed was changed to 1100 min ⁻¹ and 37.25 parts by mass of water was added dropwise at a rate of 1.0 parts by mass / min. The peripheral speed of the stirring blade at this time was 13.2 m / s. As water was added, the viscosity of the system increased, but water was taken into the system at the same time as dropping, and stirring and mixing could be performed uniformly.

  In addition, a phase inversion point at which the viscosity sharply decreased when 26 parts by mass of water was added was observed. Further, when water was added and the slurry was observed with an optical microscope, the resin was dissolved, and it was observed that the colorant and wax fine particles were dispersed. No unemulsified material was observed. Since the fine particles of the colorant and wax are stably dispersed in the aqueous medium, it is considered that the resin is adsorbed on the surface of the fine particles. At this time, the state in the system was uniform, and generation of coarse particles due to the addition was not observed.

Combined process Precipitation and combined process in the first stage After the emulsion suspension obtained in the phase inversion emulsification process was transferred to a cylindrical vessel attached to Max Blend blade (registered trademark) having a blade diameter of 340 mm, the stirring speed was 85 min. ^The temperature was adjusted to 25 ° C. while maintaining ^-1 . Thereafter, the stirring speed was increased to 120 min ⁻¹ , and 12 parts by mass of a 3.5% by mass sodium sulfate aqueous solution was dropped at a rate of 1 kg / min as the first-stage electrolyte aqueous solution. Five minutes after the completion of the dropping, the stirring speed was reduced to 85 min ⁻¹ and stirring was performed for 5 minutes, and then the stirring speed was decreased to 65 min ⁻¹ and stirring was performed for 5 minutes. Subsequently, the stirring speed was reduced to 47 min ⁻¹ and stirring for 20 minutes was continued. The particle size at this time was 2.5 μm.

Second stage coalescence process The stirring speed was adjusted to 120 min ⁻¹ , and 2 parts by mass of sodium sulfate aqueous solution having a concentration of 5 mass% was dropped at a rate of 1 kg / min as the second stage electrolyte. After 5 minutes from the end of dropping, the stirring speed was adjusted to 85 min ⁻¹ and stirring was continued for 5 minutes, and then the stirring speed was reduced to 65 min ⁻¹ and stirring was performed for 5 minutes. Subsequently, the stirring speed was adjusted to 47 min ⁻¹ and stirring for 20 minutes was continued.

Third stage coalescence step The stirring speed was adjusted to 120 min ⁻¹ , and 2 parts by mass of sodium sulfate aqueous solution having a concentration of 5 mass% was dropped at a rate of 1 kg / min as the third stage electrolyte. Five minutes after the completion of dropping, the stirring speed was adjusted to 85 min ⁻¹ and stirring was continued for 5 minutes, and then the stirring speed was reduced to 65 min ⁻¹ and stirring was continued for 5 minutes. Next, stirring was continued for 20 minutes at a stirring speed of 47 min ⁻¹ , and then 10 parts by mass of water was added as stop water to stop coalescence.

Evaluation of encapsulation of colorant After adding 0.006 parts by mass of an antifoaming agent (BY22-517 made by Toray / Dow Corning / Silicone) to 115.12 parts by mass of the emulsified suspension of particles produced in the coalescence step, Methyl ethyl ketone and water were distilled off under reduced pressure until the recovered amount was 20.8 parts by mass with respect to 100 parts by mass of the emulsified suspension.
The slurry after solvent removal was separated into a solid and a liquid using Nutsche (filter: Kiriyama 5A), and the filtrate was collected, and 610 nm by an absorbance measuring device (UV-3100 quartz cell 10 mm × 10 mm × 45 mm, optical path length 10 mm, manufactured by Shimadzu Corporation). The results are shown in Table 1.

Particle size and distribution of toner base particles 0.1 g of a surfactant (Eruclear manufactured by Chugai Photo Chemical Co., Ltd.) and 0.04 g of toner base particles are added to 20 g of water, and the toner base particles are removed using an ultrasonic disperser. After preparing by suspending in water, 50% volume average particle diameter (Dv50) and 50% number average particle diameter (Dn50) are obtained by measurement with a multisizer type II (aperture tube diameter: 100 μm) manufactured by Beckman Coulter. The particle size distribution was determined from the ratio between the two, and the results are shown in Table 1.

Example 2
In the colored resin solution preparation step, toner base particles are produced in the same manner as in Example 1 except that the same amount of resin 4 is blended instead of resin 3 which is a binder resin having a low molecular weight. Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 3
In the colored resin solution preparation step, toner base particles are produced in the same manner as in Example 1 except that the same amount of resin 5 is blended instead of resin 3 which is a binder resin having a small molecular weight. Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 4
In the colored resin solution preparation step, the same amount of resin 5 is blended instead of resin 3 which is a binder resin having a small molecular weight, and a fourth step coalescence step under the same conditions as the third step is added as a coalescence step. Except for the fact that the toner particles were grown by a total of four steps of coalescence, coalescence was conducted in the same manner as in Example 3, and the same evaluation was performed. The results are shown in Table 1.

Comparative Example 1
In the preparation of the colorant master chip 1C of Example 1, toner base particles were produced in the same manner as in Example 1 except that the resin 2 was changed to the resin 3, and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2
The resin 3 for the binder in Example 1 was changed to the resin 4, and the other conditions were the same as in Example 1 except that the resin 2 was changed to the resin 4 in the preparation of the colorant master chip 1C. Toner mother particles were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3
The resin 3 for the binder of Example 1 was changed to the resin 2, and the other conditions were the same as in Example 1 except that the resin 2 was changed to the resin 3 in the preparation of the colorant master chip 1C. Toner mother particles were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4
The resin 3 for the binder in Example 1 was changed to the resin 2, and the other conditions were the same as in Example 1 except that the resin 2 was changed to the resin 4 in the preparation of the colorant master chip 1C. Toner mother particles were produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 5
The resin 3 for the binder of Example 1 is changed to the resin 4, and in the preparation of the colorant master chip 1C, the resin 2 is changed to the resin 4, and the fourth stage under the same conditions as the third stage is used as a coalescence process. These coalescence steps were added and coalescence was performed in the same manner as in Example 3 except that the toner particles were grown by a total of four steps of coalescence steps. The results are shown in Table 1.

Claims (4)

In the method for producing a toner for developing an electrostatic charge image, a colored resin solution in which a binder resin, a colorant, and a wax are dissolved or dispersed in an organic solvent is phase-inverted and emulsified to prepare an emulsion suspension, and then an aqueous electrolyte solution is prepared. to with performing stirring added are those coalescing the dispersoids of the emulsified suspension, the binder resin is first weight average molecular weight of crosslinked polyester resin, than the first weight average molecular weight A blend of a linear polyester resin having a low second weight average molecular weight and a linear polyester resin having a third average molecular weight lower than the first weight average molecular weight and higher than the second weight average molecular weight , and the said colorant is electrostatic image development which is characterized in that blended with a master consisting of colorant and a third of the weight average molecular weight of the linear polyester resin of the binder resin Method for producing a toner. The master is prepared by subjecting the colorant and the third weight-average molecular weight linear polyester resin to melt-kneading dispersion using an open roll type continuous kneader having heating and cooling functions. The method for producing a toner for developing an electrostatic image according to claim 1. The second weight average molecular weight linear polyester resin has a weight average molecular weight of less than 5500, the first weight average molecular weight cross-linked polyester resin has a weight average molecular weight of 100,000 or more, and the third weight The method for producing a toner for developing an electrostatic charge image according to claim 1 or 2, wherein the linear polyester resin having an average molecular weight has a molecular weight of 5500 to less than 100,000. The mass ratio of the compounding quantity of the said colorant and the said 3rd weight average molecular weight linear polyester resin which comprise the said master is 30 / 70-60 / 40. A method for producing a toner for developing an electrostatic image.