JP4761064B2 - Toner manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a toner for developing an electrostatic charge image that is suitably used in a copying machine, a printer, a fax machine, and the like, and further used in a toner jet type printer.

  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. In view of demands for improving image characteristics in full-color images, toner particles used for image formation use a polymerization method, an emulsification dispersion method, or the like instead of a pulverization method in which small particle size particles are produced by pulverization.

In the toner manufacturing method by the polymerization method, since the binder resin is limited to a vinyl polymer capable of radical polymerization, the toner cannot be manufactured using a polyester resin as a raw material. In addition, the polymerization method has a problem that volatile organic compounds composed of unreacted monomers remain.
On the other hand, an emulsification dispersion method has been proposed in which particles are produced after a mixture of a binder resin and a colorant is mixed with an aqueous medium and emulsified. The emulsion dispersion method is a method in which a mixture of a binder resin and a colorant is mixed with an aqueous medium and emulsified to obtain toner particles. Therefore, since a mixed solvent is used, it is difficult to recover and reuse the solvent. In addition, there is a problem that the yield of the toner is reduced because fine particles are generated.

Therefore, a method has been proposed in which a polyester resin or the like is emulsified and dispersed as a binder resin, and then the obtained fine particles are aggregated and further heated and fused to form an aggregate. Therefore, there is a problem that it is necessary to stir at high temperature for a long time.
In addition, a method has been proposed in which fine particles are produced by emulsification and dispersion, and then the step of aggregating the fine particles and the step of fusing the agglomerated fine particles are performed at the same time. They are united by collisions between particles under force. For this reason, the coalescence tends to be non-uniform, and the generation of aggregates is inevitable. On the other hand, since emulsification and dispersion are performed under shearing force, and then the particles are aggregated under the same conditions, crushing occurs at the same time as coalescence, so the generation of fine particles increases, and the particle size distribution of the toner particles to be generated is increased. There was a limit to narrowing.

  In contrast to these methods, a phase inversion emulsification method in which a binder resin such as a polyester resin, wax, a colorant and the like are dissolved or dispersed in an organic solution, and the obtained oil phase component is dispersed and granulated in an aqueous medium A toner manufacturing method has been proposed. In this method, in order to reduce emulsification loss and obtain a sharp particle size distribution, an oil phase component is emulsified in an aqueous medium to form fine particles of the mixture in the aqueous medium, followed by dispersion stabilization. A toner is manufactured through a coalescing step in which the fine particles are coalesced by adding an agent and sequentially adding an electrolyte (see, for example, Patent Documents 1 and 2). The toner particles obtained by this production method can achieve low-temperature fixing performance by using a binder resin having a low glass transition temperature and increasing the amount of wax, but the binder resin has a low glass transition temperature. Therefore, the heat resistant storage stability of the toner particles is deteriorated. In addition, there is a problem that the exposure of the wax to the toner surface increases due to the increased amount of wax, and the development durability deteriorates.

On the other hand, as a means for solving the above problem, an aggregated particle dispersion in which aggregated particles are formed in a dispersion in which resin particles are dispersed in order to prevent exposure of the internally added wax to the toner particle surface A fine particle dispersion in which fine particles are dispersed is added and mixed in the aggregated particle dispersion, and the fine particles are adhered to the aggregated particles to form adhered particles, and the adhered particles are heated to form a core. A method for producing a toner for developing an electrostatic image having a shell structure has been studied (for example, see Patent Document 3). In this manufacturing method, since the core / shell structure is formed by heating and fusing the fine particles adhering to the surface of the aggregated particles, a low glass transition temperature resin advantageous for low-temperature fixability is used as the core particles. In addition, the exposure of the toner surface of the wax can be prevented to some extent, but a large amount of energy is required for heating and fusing, and a cooling process is also required after the heating and fusing process, and the temperature control is complicated. In other words, the toner particles are fused to generate coarse particles.
JP 2003-122051 A JP 2004-198598 A JP-A-10-26842

  The present invention relates to a method for producing a toner for developing an electrostatic charge image having a core / shell structure, wherein the core / shell structure achieves both low-temperature fixability and heat-resistant storage stability and prevents exposure of wax to the toner particle surface. An object of the present invention is to solve the problem of generation of coarse particles.

The present invention relates to a method for producing a toner for developing an electrostatic charge image having a core / shell structure, wherein a colored resin solution is obtained by dissolving or dispersing a crosslinked polyester resin, a linear polyester resin , a wax and a colorant in an organic solvent. obtaining step, a basic compound to the colored resin solution, water successively added, the step of emulsifying the colored resin solution in an aqueous medium, the aqueous electrolyte solution to the emulsion suspension emulsified said colored resin solution was added A step of forming colored resin fine particles by uniting the dispersoids in the emulsified suspension to form particles, and for forming a shell obtained by dissolving or dispersing a cross-linked polyester resin in an organic solvent . a dispersion containing the an emulsified suspension colored resin particles were mixed, the glass transition temperature of the crosslinked polyester resin emulsion suspension for the shell formation without heating And stirred while adding an electrolyte solution in full, to form particles having a core / shell structure, after removing the organic solvent under reduced pressure, separating the particles having the core / shell structure from an aqueous medium, washed And a drying step is performed. Preferably, the step of forming particles having the core / shell structure is performed at 30 ° C. or lower.
The present invention is characterized in that the toner for developing an electrostatic charge image having a core / shell structure comprises a core containing a cross-linked polyester resin and a linear polyester resin and a shell containing the cross-linked polyester resin.
In the method for producing a toner for developing an electrostatic charge image having a core / shell structure according to the present invention, heating is not required, energy for heating is saved, and cooling after heating is not required. it can. The toner for developing an electrostatic charge image having a core / shell structure according to the present invention has both low-temperature fixability and heat-resistant storage stability, prevents exposure of wax to the surface, has high development durability, and coarse particles. Is low, and both low-temperature fixability and heat-resistant storage stability are achieved.

The present invention will be described in detail below. The production method of the present invention comprises the following steps.
First step: Colored resin solution preparation step
This is a step of obtaining a colored resin solution by dissolving or dispersing a cross-linked polyester resin, a linear polyester resin , a wax and a colorant in an organic solvent.
Second step: Emulsification step
The basic compound to the colored resin solution, water successively by adding a step of emulsifying the colored resin solution in an aqueous medium.
Third process: unity process
At least one operation for forming particles by adding colored electrolyte solution to an emulsified suspension obtained by emulsifying the colored resin solution and combining the dispersoids in the emulsified suspension to form colored resin particles. It is a process to be performed.
Fourth process: Shell formation process
A shell-forming resin emulsified suspension obtained by dissolving or dispersing a cross-linked polyester resin in an organic solvent is mixed with a dispersion containing colored resin fine particles obtained in the third step, and the shell is heated without heating. This is a step of forming particles having a core / shell structure by adding an aqueous electrolyte solution below the glass transition temperature of the cross-linked polyester resin of the emulsified suspension for formation and stirring .
Fifth Step: After removing the organic solvent under separation and drying under reduced pressure, separating the particles having the core / shell structure from the aqueous medium, washed and dried is a step of the toner mother 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 cross-linked polyester resin, a linear polyester resin , a wax and a colorant are introduced into an organic solvent and dissolved or dispersed.
The cross-linked polyester resin, linear polyester resin , wax and colorant are preferably dissolved or dispersed in an organic solvent with a high-speed stirrer. In this case, the colorant may be pre-dispersed in advance to prepare a master kneading chip, and finely dispersed below the toner particle diameter to be prepared. The wax may also be mixed after preparing the master kneading chip in advance. Alternatively, a wax master solution finely dispersed below the toner particle size by wet dispersion using media may be used.

In the colored resin solution preparation step, Desper (manufactured by Asada Iron Works Co., Ltd.), T.M. K. A high-speed stirrer such as a homomixer (manufactured by PRIMIX Corporation) 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 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 shearing becomes large, 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. As such an organic solvent, for example, ketones such as methyl ethyl ketone and methyl isopropyl ketone, and esters such as ethyl acetate and isopropyl acetate are used. Two or more organic solvents can be mixed and used, but from the viewpoint of solvent recovery, it is preferable to use the same type of solvent alone. The organic solvent is a solvent that dissolves the cross-linked polyester resin and the straight-chain polyester resin, and preferably has a low boiling point because it is easy to remove the solvent in a subsequent step.

An emulsifier may be added to the organic solvent together with the cross-linked polyester resin, the linear polyester resin , the colorant and the wax.
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.
The amount of the emulsifier to be used is preferably 0.1 to 3.0% by mass, more preferably 0.3 to 2.0% by mass, and more preferably 0.3 to 1.5% by mass with respect to the solid content. It is particularly preferred that When the amount of the emulsifier to be used is less than 0.1% by mass with respect to the solid content, the desired effect of preventing the generation of coarse particles cannot be obtained. Further, when the amount of the emulsifier used is more than 3.0% by mass with respect to the solid content, the coalescence of the dispersoid in the emulsified suspension does not sufficiently proceed even if the amount of the electrolyte is increased, and the predetermined amount. As a result, fine particles remain and the yield decreases.

Then, in the emulsification step of the second step, the basic compound to the colored resin solution, water sequentially added, thereby emulsifying the colored resin solution in an aqueous medium. Here, it is preferable that the colored resin solution carboxyl groups of the crosslinking type polyester resin and linear polyester resin have been neutralized by a basic compound is added slowly water. By neutralizing the carboxyl group, the hydrophilicity of the cross-linked polyester resin and the linear polyester resin is improved, and the affinity with water is improved.
Added water is hydrated to a carboxyl group moiety of the crosslinked polyester resin and linear polyester resin, stirring effect coupled with crosslinked polyester resin and linear polyester resin is dissolved or finely dispersed. On the other hand, the cross-linked polyester resin and the linear polyester resin have an acid-base interaction intensified through an aqueous medium, and the viscosity of the system containing the colored resin solution 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. The viscosity increases until just before this, and the viscosity reaches the 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, the amount of the basic compound not only emulsification step of the second step, the uniformity of the time colored resin particles produced in the coalescence step of the third step described later, also affect the speed, crosslinked polyester resin and linear The range of 1-3 equivalent is preferable with respect to the carboxyl group of a chain-type polyester resin . Moreover, the range of 1-2 equivalent is still more preferable. In this way, by adding in excess of the amount required to neutralize all of the carboxyl groups of the cross-linked polyester resin and linear polyester resin , it is possible to prevent the formation of irregularly shaped particles in the coalescence process. In addition, the particle size distribution of the toner particles can be made narrow.

  The ratio of the organic solvent to the total amount of the organic solvent and water after the emulsification step is preferably in the range of 20 to 35% by mass, and more preferably in the range of 20 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. At the phase inversion point, the viscosity of the emulsified suspension may be high, and the colored resin solution may not be completely finely dispersed in the aqueous medium. Therefore, it is preferable to add more water. The amount of water is preferably in the range of 50 to 80% by mass of the amount of water added up to the phase inversion point and the total amount of water used up to the phase inversion point.

The cross-linked polyester resin and linear polyester resin used in the present invention are not particularly limited, but are preferably polyester resins having an acid value of 3 to 30 KOHmg / g, and the acid value of the polyester resin is 5 to 20 KOHmg / g. More preferably. When the acid value of the polyester resin is less than 3, toner particles cannot be produced. On the other hand, if the acid value of the polyester resin is greater than 30, the charge amount under the toner use environment is not stable. 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 dissolved or dispersed stably.

  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 sodium hydroxide, potassium hydroxide or ammonia is preferred.

The emulsified suspension produced by the above-described method exists in a state where the colored resin solution is emulsified in an aqueous medium. The state varies depending on the type of organic solvent, the amount used, the acid value of the cross-linked polyester resin and the linear polyester resin , the amount of basic compound used, the stirring conditions, etc., but the resin oil droplets, wax dispersoid, colorant The dispersoid such as the dispersoid is preferably emulsified as oil droplets having a particle size of less than 1 μm. Such a state is preferable because the stability of the emulsified suspension, the unitary stability in the subsequent steps, the particle size distribution of the colored resin fine particles, and the like are improved.

Next, the unification process which is the 3rd process is explained. By adding the electrolyte, the colored resin fine particles are salted out or destabilized, and the colored resin fine particles are integrated with each other, so that the coalescence proceeds and the coalesced particles are produced.
Examples of the electrolyte used here include organic and inorganic substances such as sodium sulfate, ammonium sulfate, potassium sulfate, magnesium sulfate, sodium phosphate, sodium dihydrogen phosphate, sodium chloride, potassium chloride, ammonium chloride, calcium chloride, and sodium acetate. A water-soluble salt or the like can also be used effectively as an electrolyte. These electrolytes to be added for unity may be used alone or in combination of two or more kinds. Among them, monovalent cation sulfates such as sodium sulfate and ammonium sulfate are preferable for promoting uniform coalescence.

  Moreover, since the colored resin fine particles obtained are swollen by a solvent and the hydration state of the particles is unstable due to the addition of an electrolyte, the particles are caused to collide with each other by stirring with low shearing force. It is preferable to proceed one. It is preferable to proceed the coalescence under a low shearing force such that only the coalescence proceeds without causing the splitting of the colored resin fine particles.

  In order to promote uniform coalescence, agitation conditions at the same time are important. For example, anchor blade, turbine blade, fowler blade, full zone blade, max blend blade (registered trademark, manufactured by Sumitomo Heavy Industries, Ltd.), half moon blade, etc. Is used. Among them, it is preferable to use a large wing that is excellent in uniform mixing properties even at a low rotation, 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 at a low shear of 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 higher than 10 m / s, fine particles remain, which is not preferable. On the other hand, if the peripheral speed is less than 0.2 m / s, stirring is not uniform and coarse particles are generated, which is not preferable. Under the above-described conditions, coalescence proceeds only by collision between the colored resin fine particles, and the colored resin fine particles are not dissociated and dispersed. In particular, in the coalescing process, the generation of fine particles is small and a narrow particle size distribution can be obtained.
That is, it is preferable to stir with a high-speed stirrer such as a desper in the colored resin solution preparation step and the emulsification step, and a large blade that can be uniformly mixed at a low speed such as a max blend blade is suitable in the coalescence step. For this reason, it is preferable to carry out the coalescing step by transferring the emulsified suspension obtained in the emulsifying 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. If the amount is more than 15% by mass, it is not preferable because a large amount of stop water is required in the subsequent process, and it takes time for washing and drying.
Moreover, 1-15 mass% is preferable and, as for the density | concentration of electrolyte solution, it is more preferable that it is 3-10 mass%. If the amount is less than 1% by mass, the effect of the electrolyte is not sufficiently exhibited, and a large amount of electrolyte is required for salting out and coalescence. Or, colored resin fine particles may not be generated. On the other hand, if it is higher than 15% by mass, unevenness is likely to occur in the system, and in particular, aggregates and coarse particles are likely to be generated during the formation of colored resin fine particles in the initial stage of coalescence, which is not preferable.

  In the coalescence process, when adding the aqueous electrolyte solution, it is preferable to increase the stirring speed in order to mix the electrolyte uniformly and quickly in the system. The temporary temperature is preferably in the range of 10 to 50 ° C. More preferably, it exists in the range of 20-40 degreeC, and it is especially preferable that it is 20-35 degreeC. When the temperature is lower than 10 ° C., it is difficult to perform coalescence, which is not preferable. On the other hand, when the temperature is higher than 50 ° C., the coalescence speed is increased, and aggregates and coarse particles are easily generated, which is not preferable. In the production method of the present invention, for example, colored resin fine particles can be produced by coalescence under a low temperature condition of 20 to 40 ° C.

Next, the shell formation process which is a 4th process is demonstrated. The emulsified suspension of the cross-linked polyester resin used in the shell forming step can be obtained by the same operation as the first step and the second step, except that the wax and the colorant are not used in the first step and the second step. it can. That is, for forming a shell by adding a basic compound and water sequentially to a resin solution obtained by dissolving or dispersing a crosslinkable polyester resin in an organic solvent and emulsifying the crosslinkable polyester resin solution in an aqueous medium. An emulsified suspension of a cross-linked polyester resin is prepared. An emulsified suspension of the cross-linked polyester resin for shell formation is added to the dispersion containing the colored resin fine particles obtained in the coalescing step, and an aqueous electrolyte solution is further added and stirred. The stirring conditions and the electrolyte used are the same as in the coalescing step. By adding the aqueous electrolyte solution, the fine particles of the cross-linked polyester resin for shell formation are salted out or destabilized, and the colored fine resin particles and the fine particles of the cross-linked polyester resin for shell formation are integrated with each other in the same manner as the coalescence process. The fine particles of the cross-linked polyester resin for shell formation are fixed to the surface of the colored resin fine particles, and a shell is formed on the surface of the colored resin fine particles.

In the shell formation step, the colored resin fine particles swollen by the organic solvent and the cross-linked polyester resin fine particles for shell formation collide, and the colored resin fine particles and the cross-linked polyester resin fine particles for shell formation are fixed to each other to grow particles. Go. Therefore, the shell is formed below the glass transition temperature of the cross-linked polyester resin for shell formation. Depending on the glass transition temperature of the cross-linked polyester resin for shell formation, a shell can be formed even at 30 ° C. or lower. Therefore, heating is not required in the shell forming step, and naturally, cooling after heating is not required, so that a great deal of energy is not consumed and temperature management becomes simple.

  Particle growth can be expressed by creating a blotted particle growth curve from time and particle size to maintain a nearly constant growth rate under certain conditions. As a result, the arrival time of the target particle diameter can be estimated from the curve. Moreover, it is preferable to stop shell formation by adding water.

  In order to perform solvent removal rapidly under low temperature conditions, it is preferable to carry out under reduced pressure. In removing the solvent, an antifoaming agent is preferably added. The antifoaming agent is preferably in the form of a silicone emulsion. Examples of silicone-based antifoaming agents include BY22-517, SH5503, SM5572F, BY28-503 (manufactured by Toray Dow Corning Silicone), KM75, KM89, KM98, KS604, KS538 (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. . Of these, BY22-517 is preferred as having little influence on physical properties 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 cross-linked polyester resin or linear polyester resin that is a binder resin , such as a transmission electron microscope. , It can be confirmed that a colorant, wax, etc. are encapsulated in the particles and dispersed almost uniformly.

Further, the shape of the toner particles is determined by a particle image analyzer (Sysmex flow type particle image analyzer FPIA-3000) or the like, and the degree of circularity is the circumference of a circle corresponding to the projected area of the observed particle image. It is expressed as an average circularity which is an average value of numerical values expressed as a ratio to the perimeter of the projected image of the observed particle.
Regarding the shape of the toner particles, the average circularity is preferably 0.95 or more, more preferably 0.96 or more, and further preferably 0.97 or more. This is because powder fluidity is improved and transfer efficiency is improved by making the average circularity into a substantially spherical shape or a spherical shape with 0.97 or more.

  Next, in the separation / drying step, which is the fifth step, the particles having a core / shell structure are separated, washed and dehydrated. Separation from the aqueous medium can be performed by a separation means such as a centrifuge, a filter press, or a belt filter. Next, toner base particles can be obtained by drying the particles. Drying is a fluidized bed dryer such as a ribocorn dryer (Okawara Seisakusho), a mixed vacuum dryer such as Nauta Mixer (Hosokawa Micron), a fluidized bed dryer (Okawara Seisakusho), or a vibrating fluidized bed dryer (central processing machine). However, the present invention is not limited to these dryers.

  As for the particle size distribution of the toner, it is preferable that the 50% volume particle size / 50% number particle size is 1.25 or less as measured by a multisizer type II (aperture tube diameter: 100 μm) manufactured by Beckman Coulter. More preferably, it is 20 or less. This is because it is easy to obtain a good image when it is 1.25 or less.

  The toner preferably has a 50% volume average particle diameter of 3 to 8 μm. The use of a toner having a small particle diameter not only improves the resolution and gradation, but also the thickness of the toner layer for forming a printed image. The amount of heat required for fixing can be reduced, and at the same time, the toner consumption can be reduced.

In the present invention, a crosslinked polyester resin and a linear polyester resin are used as the binder resin , and a crosslinked polyester resin is used as the shell-forming resin. The crosslinked polyester resin and linear polyester resin used in the present invention can be obtained by reacting a compound selected from the following raw materials.
The crosslinked polyester is preferably produced by reacting a divalent basic acid or derivative thereof, a divalent alcohol, and a polyvalent compound as a crosslinking agent. In particular, it is preferable to produce by reacting a divalent basic 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 basic acid with a dihydric alcohol.

  Examples of the divalent basic acid compound used for producing the crosslinked polyester resin and the linear polyester resin include phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, maleic acid, and maleic anhydride. , Fumaric acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, azelaic acid, sebacic acid and other dicarboxylic acids or derivatives thereof.

  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, Diols such as 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 Is 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 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 lysine triglycidyl ester, Trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetrakis 1,1,2,2 (P-hydroxyphenyl) ethane tetraglycidyl ether, cresol novolac epoxy resin, phenol novolac epoxy resin A polymer or copolymer of an epoxy group-containing vinyl compound, an epoxidized resorcinol-acetone condensate, a partial epoxy 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 Ethanetriglycidyl ether and pentaerythritol tetraglycidyl ether are more preferably used.
Specific examples of bisphenol A type epoxy resins include Dainippon Ink Chemical Co., Ltd. Epicron 850, Epicron 1050, Epicron 2055, Epicron 3050, and the like. Epicron 830, Epicron 520, etc. manufactured by Dainippon Ink & Chemicals, Inc. as examples of orthocresol-type novolak epoxy resins, N-660, N-665, N-667, N-670, N-673, N-680, N-690, N-695, etc. are examples of phenol novolac type epoxy resins such as Epicron N-740, N-770, N-775, N-865 manufactured by Dainippon Ink & Chemicals, Inc. As a polymer or copolymer of a vinyl compound having an epoxy group, Examples thereof 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. A specific example is Cardura E (Neodecanoic acid glycidyl ester 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.

In the present invention, the mixing ratio of the crosslinked polyester resin and the linear polyester resin is not particularly limited, but (mass of crosslinked polyester resin) / (mass of linear polyester resin) = 5 / 95-60 / 40 is preferable. 10/90 to 40/60 is more preferable, and 20/80 to 40/60 is particularly preferable. When the ratio of the cross-linked polyester resin is less than 5% by mass, the hot offset resistance, the coalescence speed, and the dispersibility of wax, colorant and the like are not preferable. On the other hand, when the ratio of the cross-linked polyester resin 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 not particularly limited, but is preferably 40 to 90 ° C, and particularly preferably 60 to 80 ° 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 developing device of the machine. On the other hand, a glass transition temperature (Tg) higher than 90 ° C. is not preferable because the low-temperature fixability is lowered.

  Although the glass transition temperature (Tg) of a linear polyester resin is not specifically limited, It is preferable that it is 35-70 degreeC, and it is especially preferable that it is 50-65 degreeC. When the glass transition temperature (Tg) is lower than 35 ° 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, a glass transition temperature (Tg) higher than 70 ° C. is not preferable because the low wrinkle fixing property is lowered.

  The softening point of the cross-linked polyester resin is not particularly limited, but is preferably 150 ° C or higher, more preferably 150 ° C to 220 ° C, and particularly preferably 170 ° C to 190 ° C. This is because when the softening point is less than 150 ° C., the toner tends to cause an aggregation phenomenon, so that trouble is likely to occur during storage or printing, and when it exceeds 220 ° C., the fixability is likely to deteriorate. is there.

  The softening point of the linear polyester resin is not particularly limited, but is preferably 90 ° C. or higher, more preferably 90 ° C. to 130 ° C., and particularly preferably 90 ° 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 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 was performed under the conditions of a piston cross-sectional area of 1 cm 2, a cylinder pressure of 0.98 MPa, a die length of 1 mm, a die hole diameter of 1 mm, a measurement start temperature of 50 ° C., a temperature increase rate of 6 ° C./min, and a sample mass of 1.5 g.
Moreover, the measurement of the glass transition temperature (Tg) of a polyester resin is measured using DSC (Shimadzu DSC-60A). 20 mg of sample is put in an aluminum crimp cell, heated to 180 ° C. at a heating rate of 10 ° C./min, cooled to room temperature at a cooling rate of 10 ° C./min from 180 ° C., and again to 180 ° C. at a heating rate of 10 ° C./min. The temperature rise and the second run value are Tg.

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-Trofisch 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 a high alcohol and a long-chain monocarboxylic acid, and hydrocarbon waxes such as Fischer-Trofisch wax are suitable. Examples of the synthetic ester wax include WEP-5 and WEP-7 (manufactured by NOF Corporation). The wax content is preferably in the range of 1 to 40% by mass with respect to the total toner. When the wax content is less than 1% by mass with respect to the total toner, the releasability becomes insufficient, and when it exceeds 40% by mass, the wax tends to be exposed on the toner particle surface, and the power failure and storage stability are reduced. It becomes easy to do.

  The colored resin solution can be prepared by mixing a charge control agent. The positively chargeable charge control agent is not particularly limited, and known and commonly used nigrosine dyes, quaternary ammonium compounds, onium compounds, triphenylmethane compounds and the like can be used for toners. In addition, basic group-containing compounds such as amino groups, imino groups, and N-heterocycles, such as tertiary amino group-containing styrene acrylic resins, are also effective as a positively chargeable charge control agent. As a control agent, it can be used alone or in combination with the 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 with these positively chargeable charge control agents. In addition, as the negatively chargeable charge control agent, heavy metals such as trimethylethane dyes, salicylic acid metal complexes, benzylic acid metal complexes, copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex azo dyes, azochrome complexes, etc. Examples thereof include acidic dyes, calixarene-type phenol condensates, cyclic polysaccharides, resins containing carboxyl groups and / or sulfonyl groups, and the like. The content of the charge control agent is preferably 0.01 to 10% by mass, and particularly preferably 0.1 to 6% by mass with respect to the whole toner.

  Examples of the colorant that can be added in the colored resin solution preparation step include 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, and carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black.

  Examples of blue colorants include 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 are 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, 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, 184, 185 and the like. Among these, C.I. I. Pigment Yellow 17, 74, 93, 97, 110, 155, 180, 184 are preferable. I. Pigment Yellow 74, 93, 97, 180, and 184 are more preferable. I. Pigment Yellow 93, 97, 180, and 184 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, 112, 114, 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, 22 4, 242, 243, 243: 1, 245, 246, 247 and the like. Among these, C.I. I. Pigment Red 48: 1, 48: 2, 48: 3, 48: 4, 53: 1, 57: 1, 122, 184, 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, more preferably 2 to 18% by mass, and still more preferably 2 to 15% by mass with respect to the whole toner. These colorants can be used alone or in combination of two or more.

  The toner particles produced by the production method of the present invention can be adjusted in fluidity, electrostatic property, etc. by adding fine particles such as silica and titania or those hydrophobized to these 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.

(Synthesis of cross-linked polyester resin 1)
Terephthalic acid 221 parts by mass Isophthalic acid 95 parts by mass Neopentyl glycol 104 parts by mass Ethylene glycol 62 parts by mass Tetrabutyl titanate 2.5 parts by mass Epicron 830 7 parts by mass (Dai Nippon Ink Chemical Co., Ltd. bisphenol F type epoxy resin Epoxy Equivalent 170 g / eq)
3 parts by weight of Cardura E (Shell Japan alkyl glycidyl ester epoxy equivalent 250 g / eq)
The above raw materials were put into a stainless steel 50 L reaction kettle and reacted 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 the softening point specified in ASTM E28-517, and the reaction was terminated when the softening point reached 160 ° C. The obtained polymer was a colorless solid having an acid value of 11.0, a glass transition temperature of 64 ° C. by DSC measurement method, and a softening point (T1 / 2) by a flow tester of 175 ° C. The polymer is hereinafter referred to as “H1”.

(Synthesis of cross-linked polyester resin 2)
Terephthalic acid 95 parts by mass Isophthalic acid 221 parts by mass Neopentyl glycol 104 parts by mass Ethylene glycol 62 parts by mass Tetrabutyl titanate 2.5 parts by mass Epicron 830 7 parts by mass (Dai Nippon Ink Chemical Co., Ltd. bisphenol F type epoxy resin Epoxy Equivalent 170 g / eq)
3 parts by weight of Cardura E (Shell Japan alkyl glycidyl ester epoxy equivalent 250 g / eq)
The above raw materials were put into a stainless steel 50 L reaction kettle and reacted 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 the softening point specified in ASTM E28-517, and the reaction was terminated when the softening point reached 158 ° C. The obtained polymer was a colorless solid having an acid value of 9.4, a glass transition temperature of 64 ° C. by DSC measurement method, and a softening point (T1 / 2) by a flow tester of 173 ° C. The polymer is hereinafter referred to as “H2”.

(Synthesis of linear polyester resin 1)
Terephthalic acid 315 parts by mass Neopentyl glycol 21 parts by mass Ethylene glycol 12 parts by mass Propylene glycol 122 parts by mass Tetrabutyl titanate 2.5 parts by mass or more of raw materials are placed in a stainless steel 50 L reaction kettle and 240 under a normal pressure nitrogen stream. After the reaction at 12 ° C. for 12 hours, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point specified in ASTM E28-517, and the reaction was terminated when the softening point reached 100 ° C. The obtained polymer was a colorless solid having an acid value of 10.0, a glass transition temperature of 57 ° C. by DSC measurement method, and a softening point (T1 / 2) by a flow tester of 102 ° C. The polymer is hereinafter referred to as “L2”.

(Synthesis of linear polyester resin 2)
Terephthalic acid 315 parts by weight Isophthalic acid 18.9 parts by weight Neopentyl glycol 155 parts by weight Ethylene glycol 155 parts by weight Propylene glycol 122 parts by weight Tetrabutyl titanate 6.25 parts by weight or more of raw materials are placed in a 50 L stainless steel reaction kettle. After reacting at 240 ° C. for 12 hours under a pressurized nitrogen stream, the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point specified in ASTM E28-517, and the reaction was terminated when the softening point reached 94 ° C. The obtained polymer was a colorless solid having an acid value of 9.0, a glass transition temperature of 46 ° C. by DSC measurement, and a softening point (T1 / 2) by a flow tester of 95 ° C. The polymer is hereinafter referred to as “L3”.

(Synthesis of linear polyester resin 3)
Terephthalic acid 315 parts by weight Isophthalic acid 472.5 parts by weight Neopentyl glycol 155 parts by weight Ethylene glycol 155 parts by weight Propylene glycol 122 parts by weight Tetrabutyl titanate 6.25 parts by weight or more of raw materials are placed in a 50 L stainless steel reaction kettle. The reaction was continued at 240 ° C. for 10 hours under a pressurized nitrogen stream, then the pressure was reduced successively and the reaction was continued at 10 mmHg. The reaction was followed by the softening point specified in ASTM E28-517, and the reaction was terminated when the softening point reached 85 ° C. The obtained polymer was a colorless solid having an acid value of 10.0, a glass transition temperature of 40 ° C. by DSC measurement, and a softening point (T1 / 2) of 87 ° C. by a flow tester. The polymer is hereinafter referred to as “L4”.

(Preparation of wax master solution)
Carnauba wax (Carnauba wax No. 1, imported by Yoko Kato) 30 parts by mass, linear polyester resin L2 70 parts by mass and methyl ethyl ketone 150 parts by mass were premixed with Desper and then Starmill LMZ-10 (Ashizawa Finedec The wax master solution W-1 having a solid content of 40% by mass was prepared. The composition of W-1 is L2 / wax / methyl ethyl ketone = 28/12/60.

(Preparation of colorant master chip)
Ket Bleu 111 (Dai Nippon Ink Chemical Co., Ltd. Cyan Pigment, CI Pigment B-15: 3) 2000 parts by mass and linear polyester resin L2 2000 parts by mass 20 L Henschel set with ST / A0 blades The mixture was put into a mixer (Mitsui Mine Co., Ltd.) and stirred at 698 min -1 for 2 minutes to obtain a mixture. The mixture was melt-kneaded using a kneedex MOS140-800 (an open roll continuous extrusion kneader manufactured by Mitsui Mining Co., Ltd.) to prepare a master chip. Similarly, master chips were prepared for Permanentorubin F6B (magenta pigment manufactured by Clariant Japan), Toner Yellow HG (yellow pigment manufactured by Clariant Japan), and ELFTEX (carbon black manufactured by Cabot). The obtained master chip was diluted with linear polyester resin L2 and methyl ethyl ketone, and when the dispersion state of the colorant and the presence or absence of coarse particles were observed with a 400 times optical microscope, the colorant was uniformly dispersed and coarse particles There was no. The composition of each colorant master chip is as follows: cyan pigment / linear polyester resin L2 = 50/50, magenta pigment / linear polyester resin L2 = 50/50, yellow pigment / linear polyester resin L2 = 55/45 Carbon black / linear polyester resin L2 = 50/50. Hereinafter, the cyan pigment master chip is referred to as PC, the magenta pigment master chip as PM, the yellow pigment master chip as PY, and the black pigment master chip as PB.

(Preparation of colored resin solution)
Use the above-mentioned wax master solution, colorant master chip, cross-linked polyester resin H1, linear polyester resin L2 and methyl ethyl ketone in the range of 40 to 45 ° C. with a blade diameter of 9 inches (manufactured by Asada Iron Works Co., Ltd.). The mixture was mixed at 777 min ⁻¹ for 2 hours to dissolve and disperse.
Methyl ethyl ketone is further added to the resulting mixture to adjust the solid content to 65% by mass, and 2.20 parts by mass of dodecylbenzenesulfonic acid-based emulsifier Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) A colored resin solution was prepared by adding, dissolving and dispersing. The composition of the prepared colored resin solution is shown in Table 1.

(Core particle preparation step 1)
(Emulsification process)
A cylindrical container having a blade with a blade diameter of 230 mm as a stirring blade was charged with 545.5 parts by mass of colored resin solution MB-1 (solid content of 300 parts by mass), and then added with 50 parts by mass of 1 N ammonia water, which was 777 min ^−. After stirring at ¹ , the temperature was adjusted to 35 ° C. Next, the stirring speed was changed to 1100 min ⁻¹ and 590.1 parts by mass of deionized water was added dropwise at 10 parts by mass / min to prepare an emulsified suspension. The peripheral speed of the stirring blade at this time was 13.2 m / s. As deionized water was added, the viscosity of the system increased, but water was taken into the system at the same time as the dropwise addition, and stirring and mixing were uniform. After adding 250 parts by weight of deionized water, a sharp drop in viscosity was observed (phase inversion emulsification). Further, when a predetermined amount of the remaining deionized water was added and the slurry was observed with an optical microscope, it was observed that the resin was dissolved and the pigment and wax fine particles were dispersed. No unemulsified material was observed. Since the pigment and wax fine particles are stably dispersed in the aqueous medium, it is considered that the resin is adsorbed on the surfaces of the fine particles.

(Joint process)
Next, the emulsified suspension was transferred to a cylindrical vessel attached to a Max Blend blade (registered trademark, manufactured by Sumitomo Heavy Industries, Ltd.) having a blade diameter of 340 mm, and the temperature was maintained at 26 ° C. while maintaining the stirring speed at 85 min ^−1. Adjusted. Thereafter, the rotational speed was adjusted to 120 min ⁻¹ , 120 parts by mass of a 3.5 mass% sodium sulfate aqueous solution was added dropwise at 10 parts by mass / min, and 5 minutes after the completion of dropping, the rotational speed was 85 min ⁻¹ for 5 minutes and 65 min. ^The mixture was stirred for 5 minutes at ^-1 and continued for 20 minutes at 47 min- ¹ . The peripheral speed of the stirring blade at this time was 0.47 m / s. Subsequently, the rotational speed was adjusted to 120 min ⁻¹ , 20 parts by mass of a sodium sulfate aqueous solution having a concentration of 5.0% by mass was dropped at 10 parts by mass / min, and 5 minutes after the completion of the dropping, the rotational speed was 85 min ⁻¹ for 5 minutes. Stirring was performed at 65 min ⁻¹ for 5 minutes, and stirring was continued at 47 min ⁻¹ for 20 minutes. Thereafter, the operation of dropping and stirring 20 parts by mass of a sodium sulfate aqueous solution having a concentration of 5.0% by mass at 10 parts by mass / min was repeated to obtain a dispersion containing colored resin fine particles having a particle size of 5.2 μm.

(Core particle preparation step 2)
(Emulsification process)
An emulsified suspension was prepared in the same manner as in the core particle preparation step 1 except that the colored resin solution MB-2 was used.

(Joint process)
Next, the emulsified suspension was transferred to a cylindrical vessel attached to a Max Blend blade (registered trademark, manufactured by Sumitomo Heavy Industries, Ltd.) having a blade diameter of 340 mm, and the temperature was maintained at 26 ° C. while maintaining the stirring speed at 85 min ^−1. Adjusted. Thereafter, the rotational speed was adjusted to 120 min ⁻¹ , 120 parts by mass of a 3.5 mass% sodium sulfate aqueous solution was added dropwise at 10 parts by mass / min, and 5 minutes after the completion of dropping, the rotational speed was 85 min ⁻¹ for 5 minutes and 65 min. ^The mixture was stirred for 5 minutes at ^-1 and continued for 20 minutes at 47 min- ¹ . The peripheral speed of the stirring blade at this time was 0.47 m / s. Subsequently, the rotational speed was adjusted to 120 min ⁻¹ , 20 parts by mass of a sodium sulfate aqueous solution having a concentration of 5.0% by mass was dropped at 10 parts by mass / min, and 5 minutes after the completion of the dropping, the rotational speed was 85 min ⁻¹ for 5 minutes. Stirring was performed at 65 min ⁻¹ for 5 minutes, and stirring was continued at 47 min ⁻¹ for 20 minutes to obtain a dispersion containing colored resin fine particles having a particle diameter of 5.2 μm.

(Core particle preparation step 3)
(Emulsification process)
An emulsified suspension was prepared in the same manner as in the core particle adjustment step 1 except that the colored resin solution MB-3 was used.

(Joint process)
Next, the emulsified suspension was transferred to a cylindrical vessel attached to a Max Blend blade (registered trademark, manufactured by Sumitomo Heavy Industries, Ltd.) having a blade diameter of 340 mm, and the temperature was maintained at 26 ° C. while maintaining the stirring speed at 85 min ^−1. Adjusted. Thereafter, the rotational speed was adjusted to 120 min ⁻¹ , 120 parts by mass of a 3.5 mass% sodium sulfate aqueous solution was added dropwise at 10 parts by mass / min, and 5 minutes after the completion of dropping, the rotational speed was 85 min ⁻¹ for 5 minutes and 65 min. ^The mixture was stirred for 5 minutes at ^-1 and continued for 20 minutes at 47 min- ¹ . The peripheral speed of the stirring blade at this time was 0.47 m / s. Subsequently, the rotational speed was adjusted to 120 min ⁻¹ , and 15 parts by mass of a sodium sulfate aqueous solution having a concentration of 5.0 mass% was dropped at 10 parts by mass / min, and 5 minutes after the completion of the dropping, the rotational speed was 85 min ⁻¹ for 5 minutes. Stirring was performed at 65 min ⁻¹ for 5 minutes, and stirring was continued at 47 min ⁻¹ for 20 minutes to obtain a dispersion containing colored resin fine particles having a particle diameter of 5.2 μm.

(Core particle preparation step 4)
(Emulsification process)
An emulsified suspension was prepared in the same manner as in the core particle adjustment step 1 except that the colored resin solution MB-4 was used.
(Joint process)
It processed like the coalescence process of the core particle preparation adjustment process 3, and obtained the dispersion liquid containing the coloring resin microparticles | fine-particles with a particle size of 5.3 micrometers.

(Core particle preparation step 5)
(Emulsification process)
An emulsified suspension was prepared in the same manner as in the core particle preparation step 1 except that the colored resin solution MB-5 was used.
(Joint process)
It processed like the coalescence of the core particle adjustment process 3, and obtained the dispersion liquid containing the coloring resin fine particle with a particle size of 5.2 micrometers.

(Core particle preparation step 6)
(Emulsification process)
An emulsified suspension was prepared in the same manner as in the core particle preparation step 1 except that the colored resin solution MB-6 was used.
(Joint process)
It processed like the coalescence process of the core particle preparation process 3, and obtained the dispersion liquid containing the coloring resin microparticles | fine-particles of particle size 5.2 micrometers.

(Shell particle preparation process)
(Preparation of resin solution for shell formation)
In a cylindrical container, 100 mass parts of cross-linked polyester resin H1, 122.2 mass parts of methyl ethyl ketone, and 0.7 mass parts of sodium alkylbenzenesulfonate (Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.)) are 40-45. Using a Desper (made by Asada Iron Works Co., Ltd.) having a blade diameter of 230 mm in the range of 0 ° C., the mixture was mixed at 777 min ⁻¹ for 1 hour, and dissolved and dispersed to prepare a shell forming resin solution.

(Emulsification process)
The resin solution for shell formation prepared above was charged with 222.2 parts by mass (100 parts by mass of solid content), then 29.4 parts by mass of 1N ammonia water was added and stirred at 777 min ⁻¹ , and the temperature was 35 ° C. Adjusted. Subsequently, the stirring speed was changed to 1100 min ⁻¹ and 230.8 parts by mass of deionized water was added dropwise at 10 parts by mass / min to prepare an emulsion. The peripheral speed of the stirring blade at this time was 13.2 m / s. As deionized water was added, the viscosity of the system increased, but water was taken into the system at the same time as the dropwise addition, and stirring and mixing were uniform. After adding 155 parts by weight of deionized water, a sharp drop in viscosity was observed (phase inversion emulsification). As a result of microscopic observation, an unemulsified product was not observed. At this time, the ratio of methyl ethyl ketone in all the solutions in the system was 31.9% by mass.

Example 1
The colored resin fine particle dispersion obtained from the core particle preparation step 1 is heated at a temperature of 25 ° C. and a rotation speed of 120 min ^{−1 in} a cylindrical container attached to a Max Blend blade (registered trademark, manufactured by Sumitomo Heavy Industries, Ltd.) having a blade diameter of 340 mm. 58 parts by mass of the emulsion suspension for shell obtained in the shell particle preparation step was added dropwise at 5 parts by mass / min, and 2 minutes after the completion of the addition, the emulsion was stirred at a rotational speed of 75 min ⁻¹ for 10 minutes. This dropping and stirring of the emulsified suspension for shell was further performed twice in the same manner, and 174 parts by mass of the emulsified suspension for shell was dropped in total. Thereafter, the rotational speed was adjusted to 120 min ⁻¹ , 30 parts by mass of a 5.0 mass% sodium sulfate aqueous solution was dropped at 10 parts by mass / min, and 5 minutes after the completion of dropping, the rotational speed was 85 min ⁻¹ for 5 minutes. Stirring was performed at 65 min ⁻¹ for 5 minutes, and stirring was continued at 47 min ⁻¹ , and 400 parts by weight of dilution water was added when the particle size grew to 5.8 μm.

(Separation and drying process)
Then, after adding 0.0068 mass parts of antifoamer BY22-517 (made by Toray Dow Corning Silicone Co., Ltd.), methyl ethyl ketone and water were distilled off under reduced pressure until the degree of vacuum became 4 kPa. The slurry after the solvent removal was repeatedly washed by solid-liquid separation and redispersion, and then a colored resin fine particle dispersion obtained by removing the solvent with a basket type centrifuge was obtained. Thereafter, drying was performed with a mixing vacuum dryer to obtain toner mother particles. A core / shell structure was confirmed by observing a cross-section of the toner base particles with a microtome with a transmission electron microscope.

(External addition process)
1 part by mass of silica H13TM (manufactured by Clariant Japan) was added to 100 parts by mass of the toner base particles, and these were treated with a Henschel mixer at 35 m / sec for 5 minutes to obtain toner base particles.

(Example 2)
Toner base particles in the same manner as in Example 1 except that the colored resin fine particle dispersion obtained from the core particle preparation step 2 is used instead of the colored resin fine particle dispersion obtained from the core particle preparation step 1 in Example 1. Got.

(Example 3)
Toner base particles in the same manner as in Example 1 except that the colored resin fine particle dispersion obtained from the core particle preparation step 3 is used instead of the colored resin fine particle dispersion obtained from the core particle preparation step 1 in Example 1. Got.

Example 4
In the same manner as in Example 1, except that the colored resin fine particle dispersion obtained from the core particle preparation step 4 is used instead of the colored resin fine particle dispersion obtained from the core particle preparation step 1 in Example 1, the toner base particles are used. Got.

(Example 5)
In the same manner as in Example 1 except that the colored resin fine particle dispersion obtained from the core particle preparation step 5 is used instead of the colored resin fine particle dispersion obtained from the core particle preparation step 1 in Example 1. Got.

(Example 6)
In the same manner as in Example 1 except that the colored resin fine particle dispersion obtained from the core particle preparation step 6 is used instead of the colored resin fine particle dispersion obtained from the core particle preparation step 1 in Example 1, Got.

(Comparative Example 1)
In the core particle preparation step 1, after obtaining a dispersion containing colored resin fine particles having a particle size of 5.2 μm, the number of revolutions was adjusted to 120 min ^−1, and 5 parts by mass of a 5.0 mass% sodium sulfate aqueous solution was added to 10 parts. was added dropwise at mass parts / min, after completion of the dropwise addition 5 minutes, at a rotational speed 85Min ^-1 5 minutes, and stirred at 65Min ^-1 5 minutes, and continued stirring at 47Min ^-1, a particle size grew to 5.8μm 400 parts by weight of dilution water was added in stages.
Subsequent separation, drying and external addition steps were carried out in the same manner as in Example 1 to obtain toner mother particles.

  Table 2 shows the evaluation results of the toner base particles obtained in Examples 1 to 6 and Comparative Example 1. The measuring method of each physical property shown in Table 2 is as follows.

(Particle size distribution)
Using a 100 micron aperture tube of Coulter Multisizer II (manufactured by Coulter Beckman), 50% volume average diameter / 50% number average diameter was determined.

(Low temperature fixability test)
Regarding the fixing temperature range, the fixing temperature was determined by the following fixability test, and the range between the upper limit value and the lower limit value was defined as the fixing temperature range. A test sample in which an unfixed image was formed on paper was prepared using a printer remodeling machine using a commercially available organic optical semiconductor as a photoconductor, and the test sample was heated at a speed of 90 mm / sec. (Oilless type) Fixing is performed, cellotape (registered trademark) is pasted on the fixed image, the ID (image density) after peeling is 90% or more of the original ID, and an offset is generated. The surface temperature of the heat roll when it was not seen was defined as “fixing temperature”.

(Heat resistant storage stability test)
3 g of toner base particles were placed in a glass 30 cc bottle and stored at a temperature of 55 ° C./humidity of 30% for 12 hours, and aggregation of the toner base particles was observed. A case where the toner base particles are not aggregated is indicated by ◯, a case where the toner base particles are partially aggregated is indicated by Δ, and a case where the toner base particles are aggregated is indicated by ×.

(Durability printing performance test)
A durability printing test was conducted using a color laser printer Epson LP-9000C. It is indicated by ○ when the number of successfully printed sheets is 5000 or more, Δ when 2000 or more and less than 5000 sheets (practical lower limit), and x when 1000 sheets or less (unusable).

(Charge amount)
A developer having a ratio of silicon-coated ferrite carrier (Powder Tech Co., Ltd.) and toner base particles of 97/3 was prepared, and the developer was stirred for 60 minutes, and the charge amount was measured by a suction type small charge amount measuring device Model 210HS- It was measured with 2A (manufactured by Trek Japan Co., Ltd.).

(Wax exposure by total reflection FT-IR)
5 g of toner mother particles were pressed with a load of 9 t for 1 minute using a 50-ton press (manufactured by Shimadzu Corporation) to produce 50 mmφ (2.5 mm thick) pellets. The pellet surface was measured by FTIR600Plus and IRT-30 (microscopic FT-IR manufactured by JASCO Corporation). The objective used was ATR-30-G45, and measurement was performed with a germanium crystal having a diameter of 100 μm. At this time, the incident angle was 45 °, and the number of integrations was auto (the number of integrations was 95 to 97). The intensity of the obtained wax-derived peak (2859 cm @ -1) was defined as the relative amount of wax near the toner surface. Further, in order to confirm the presence state of the wax in the toner, observation with a transmission electron microscope has confirmed that there is a correlation between the state dispersed near the toner surface and the peak intensity derived from the wax. From this result, it can be said that when the peak value derived from the wax is 7 or more, the exposure of the wax from the toner surface is large, and when it is 5 or less, the exposure from the toner surface is small.

It can be seen that the toner particles having the core / shell structure obtained in Examples 1 to 6 which are the production methods of the present invention do not contain coarse particles and there is no exposure of the wax to the toner particle surfaces. On the other hand, the toner particles of Comparative Example 1 that have not been subjected to the shell formation step do not contain coarse particles, but do not have a core / shell structure and the wax is exposed on the surface of the toner particles. It is. Further, in Examples 1 to 3, when the fixing temperature range is observed, the lower limit value of the fixing temperature range is low when the glass transition temperature of the core particle resin is low, and it is understood that the low temperature fixing property is excellent. . Comparative Example 1 is excellent in low-temperature fixability, but has no heat-resistant storage stability because the shell is not formed, and the durable printing performance is also low. Therefore, the toner particles obtained by the production method of the present invention in which a shell is formed on the surface of the coalesced particles are excellent in low-temperature fixability, heat-resistant storage stability, and durable printability.

Claims (3)

A step of obtaining a colored resin solution by dissolving or dispersing a cross-linked polyester resin, a linear polyester resin , a wax and a colorant in an organic solvent;
The basic compound to the colored resin solution, the step of water sequentially added, thereby emulsifying the colored resin solution in an aqueous medium,
Adding an electrolyte aqueous solution to an emulsified suspension obtained by emulsifying the colored resin solution and combining the dispersoids in the emulsified suspension to form colored resin fine particles to form particles;
A dispersion of crosslinked polyester resin an emulsified suspension for dissolving or shell formation obtained by dispersing in an organic solvent containing the colored resin particles were mixed, the emulsion suspension for shell formation without heating Adding an aqueous electrolyte solution below the glass transition temperature of the liquid crosslinked polyester resin and stirring to form particles having a core / shell structure;
The electrostatic image development having a core / shell structure, wherein the organic solvent is removed under reduced pressure, and then the particles having the core / shell structure are separated from the aqueous medium, washed, and dried. Of manufacturing toner. The method for producing a toner for developing an electrostatic charge image having a core / shell structure according to claim 1, wherein the step of forming particles having the core / shell structure is performed at 30 ° C or lower. A static having a core / shell structure manufactured by the manufacturing method according to claim 1 or 2 , comprising a core containing a cross-linked polyester resin and a linear polyester resin and a shell containing the cross-linked polyester resin. Toner for charge image development.