JP4609142B2 - Toner manufacturing method for developing electrostatic image - Google Patents

Description

The present invention is a copying machine, a printer, an electrophotographic apparatus using an electrophotographic process such as a facsimile, relates to the production how the toner over for developing an electrostatic image used for the development of the electrostatic image.

  Many methods are known as electrophotographic methods (see, for example, Patent Document 1). Generally, an electrostatic latent image is electrically formed on the surface of a photoreceptor (latent image carrier) using a photoconductive substance by various means, and the formed electrostatic latent image is used with toner. After developing to form a toner image, the toner image is transferred to the surface of a recording medium such as paper, optionally via an intermediate transfer member, and fixed by heating, pressing, heating and pressing, or solvent vapor. An image is formed through a plurality of processes. Further, the toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is used again for developing the toner image.

  As a fixing technique for fixing the toner image transferred on the surface of the recording medium, there is a hot roll fixing method in which the recording medium having the toner image transferred is inserted between a pair of rolls consisting of a heating roll and a pressure roll and fixed. It is common. As a similar technique, a fixing method in which one or both of the rolls is replaced with a belt is also known. These techniques, compared to other fixing methods, provide high-speed and robust images, high energy efficiency, and less harm to the environment due to volatilization of solvents and the like.

  On the other hand, the toner image transferred to the surface of the recording medium through the transfer process is melted by being heated by the fixing member heated in the fixing process, and is fixed to the surface of the recording medium. It is known that in the fixing step, the toner image is not fixed unless the recording medium is sufficiently heated by the fixing member. If the recording medium is not sufficiently heated, only the toner is melted by the heating from the fixing member, and a so-called cold offset that adheres to the fixing member occurs.

  Further, when the recording medium or the toner image is excessively heated, the viscosity of the toner is reduced, and so-called hot offset occurs in which a part or all of the toner image adheres to the fixing member side. Accordingly, it is necessary to set the fixing conditions so that both the cold offset and the hot offset do not occur when the fixing member is used to heat the recording medium or the toner image transferred to the surface thereof.

  On the other hand, in order to save power in the fixing process that occupies a certain amount of power consumption as the demand for energy saving required for image formation increases, and in order to expand the fixing conditions, the toner fixing temperature It is necessary to lower the temperature. By lowering the toner fixing temperature, in addition to the power saving and the expansion of the fixing conditions, the waiting time until the fixing temperature on the surface of the fixing member such as a fixing roll at the time of power input, that is, the so-called warm-up time is shortened. The time can be extended and the life of the fixing member can be extended.

  However, in order to lower the fixing temperature of the toner, it is necessary to lower the glass transition point of the toner particles at the same time, resulting in a decrease in the storage stability of the toner. Therefore, in order to achieve both low-temperature fixing and toner storage stability, the toner has a so-called sharp melt property in which the viscosity of the toner rapidly decreases in a high temperature region while keeping the glass transition point of the toner at a higher temperature. Required for toner.

However, since the binder resin used in the toner usually has a certain range of glass transition point, molecular weight, etc., in order to obtain the sharp melt property, it is necessary to make the composition and molecular weight of the binder resin extremely uniform. is there.
In order to obtain such a highly uniform resin, it becomes necessary to adjust the molecular weight of the resin by using a special production method or by treating the resin with chromatography or the like. In this case, the cost for producing a highly uniform resin is inevitably high, and unnecessary resin (waste) is produced when producing a highly uniform resin, which is preferable from the viewpoint of environmental protection in recent years. Absent.

  On the other hand, if the printed material on which the image is formed is stored for a long time in a stacked state, there may be a problem that a part or all of the image is transferred to the back of the stacked upper paper (hereinafter referred to as “upper sheet”). , Called “document offset”). This phenomenon is particularly accelerated when the printed matter is stored under high temperature and high humidity conditions. Therefore, there is a demand for an image forming method capable of maintaining a clear image even under conditions where image storage stability deteriorates.

  In view of the above, there is a strong demand for a so-called wide fixing latitude toner that can be fixed at a low temperature and that does not cause an offset to a higher temperature region, and an image forming method capable of obtaining an image that can withstand document offset.

  As a means for preventing the occurrence of offset, a method using a binder resin blended with a high molecular polymer or a crosslinked polymer (for example, see Patent Document 2, Patent Document 3, etc.) is known. By increasing the surface cohesive force, measures are taken to prevent toner fusion to the surface of the fixing member. However, although these methods are effective in preventing offset, there arises a problem that the fixing temperature rises.

  In order to improve the releasability from the surface of the fixing member, attempts have been made to add low molecular weight components such as polypropylene, polyethylene, alkylamide compounds, and ester compounds to the toner. Although these methods can improve offset resistance, in the case of a toner obtained by a conventional kneading and pulverizing method, a phase in which a low molecular weight component, which is a release agent contained in the toner, is ruptured in the pulverizing step. Therefore, a low molecular weight component is exposed on the surface of the toner obtained by pulverization. Therefore, there are concerns about the storage stability of the toner and developer, such as inducing blocking and impairing the fluidity of the toner.

  On the other hand, as a means for lowering the toner fixing temperature, a technique for lowering the glass transition point of the binder resin is generally performed. However, if the glass transition point is too low, powder aggregation (blocking) tends to occur, and the toner preservability on the fixed image is lost. Therefore, the lower limit of the glass transition point of the toner is practically 60 ° C. Although this glass transition point is a design point of many commercially available toner resins (binder resins), at present, it has not been possible to obtain a toner that can be fixed at low temperature by the method of lowering the glass transition point. . Although the fixing temperature can be lowered by using a plasticizer, there is a problem that toner blocking occurs during storage or in the developing machine.

  As means for achieving both blocking prevention, image storage stability, and low-temperature fixability, a method using a crystalline resin as a binder resin has been known for a long time (see, for example, Patent Document 4, Patent Document 5, etc.). However, the crystalline resin is difficult to pulverize by the kneading pulverization method and has a low yield. Even if practicality in production can be secured, the fixing temperature can be lowered, but sufficient offset resistance cannot always be obtained. That is, although the melted toner penetrates into the paper, it has an effect of preventing the occurrence of offset, but the melted toner soaks into the paper so that a uniform and high density image cannot be obtained. .

  As means for solving the above problems, many techniques for using a crystalline resin and an amorphous resin in combination, instead of using a crystalline resin alone as a binder resin, have been proposed. It is also known that when a toner is prepared by a kneading and pulverizing method, pulverization is facilitated by including an amorphous resin. For example, a method using a crystalline resin and an amorphous resin in combination (for example, see Patent Document 6), or a method using a resin in which a crystalline resin and an amorphous resin are chemically bonded (for example, Patent Document 7). To 11).

  However, when the amorphous resin contained in the toner is more than the crystalline resin, the amorphous resin forms a continuous phase in the toner and forms a phase in which the crystalline resin is dispersed. In this case, since the crystalline resin is covered with the amorphous resin, there is no problem with the crystalline resin. On the other hand, the melting characteristics of the entire toner are governed by the softening temperature of the amorphous resin, so that the low temperature fixing is performed. It is difficult to realize the sex.

  As described above, in order to improve both the low-temperature fixability and the offset resistance, it is difficult to use a crystalline resin that is effective for the low-temperature fixability and the offset resistance in the melt-kneading pulverization method. However, there is a problem that sufficient performance cannot be obtained even if a resin having a high molecular weight or a crosslinked structure is used. Furthermore, since the pulverization is performed, it is difficult to control the shape of the toner particles. In particular, it is difficult to make the toner particles spherical, and it is difficult to reduce the toner particle size for the purpose of improving the image quality.

As a toner manufacturing method for solving the above-mentioned problem, there is a wet manufacturing method in which toner particles are prepared by polymerization such as suspension polymerization (for example, see Patent Document 12). When a wet manufacturing method such as a suspension polymerization method is used, toner particles that are difficult to knead and pulverize can be easily manufactured, and the shape of the toner particles can be controlled, and spherical toner particles can be easily prepared. it can. In addition, the particle size distribution of the toner particles can be controlled. Therefore, there is no need to provide a classification step which is essential for the purpose of homogenizing the toner particles obtained by the kneading and pulverizing method described above.
However, the suspension polymerization method using a crystalline resin has a problem that it is difficult to uniformly disperse the colorant in the toner.

  On the other hand, the volume resistance value of the toner used in the electrophotographic process is an important characteristic value that influences the charging characteristics, but the volume resistance value of the crystalline resin is an amorphous resin in the molecular weight region that has been conventionally used. In contrast, the crystalline resin alone is difficult to secure the charging characteristics necessary for electrophotography.

  Therefore, for the purpose of improving the above problems, the emulsified or suspended resin particles containing these components are agglomerated and fused in a solution in which a crystalline resin is dissolved in a radical polymerizable monomer that forms an amorphous polymer. A method for obtaining toner particles by applying the toner particles has been proposed (see Patent Document 13). However, in this method, when the proportion of the crystalline resin phase contained in the toner is large, the proportion of the crystalline resin exposed to the toner surface increases. In this case, there is a problem that the chargeability of the toner is adversely affected due to the inherent low resistance of the crystalline resin as described above.

As described above, in the toner using the crystalline resin, it is difficult to ensure sufficient chargeability as well as the low-temperature fixability which is an advantage of the crystalline resin. In addition, in order to satisfy both hot offset resistance and document offset resistance, it is required to satisfy both conflicting characteristics, and furthermore, no toner that satisfies powder flowability and other toner characteristics has yet been provided. is the current situation.
Therefore, there is a need for a toner having excellent storability such as sufficient chargeability, document storability and toner storability in addition to low-temperature fixability. In addition, there is a need for a toner that can achieve other characteristics at a high level.

Japanese Patent Publication No.42-23910 JP 50-134652 A JP-A-51-23354 Japanese Patent Publication No. 56-13943 Japanese Examined Patent Publication No.62-39428 Japanese Patent Laid-Open No. 2-79860 JP-A-1-163756 Japanese Patent Laid-Open No. 1-163757 JP-A-4-81770 JP-A-4-155351 JP-A-5-44032 Japanese Patent Publication No. 36-10231 JP 2001-42564 A

  An object of the present invention is to solve the above problems. That is, the present invention is a toner for developing an electrostatic charge image that can be fixed at a low temperature and has sufficient chargeability and excellent storage stability, a method for producing the same, a developer for developing an electrostatic charge image using the same, and It is an object to provide an image forming method.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1>
At least an amorphous polyester resin, a colorant, and an ester compound represented by the following general formula (1) are each dispersed in an aqueous medium to prepare a resin particle dispersion, a colorant dispersion, and an ester compound dispersion. Process,
An agglomeration step of forming aggregated particles in a raw material dispersion containing the resin particle dispersion, the colorant dispersion, and the ester compound dispersion;
At least through a fusing step of fusing the aggregated particles by heating , the ester compound comprises the amorphous polyester resin and the colorant, and the ester compound with respect to 100 parts by weight of the amorphous polyester resin. An electrostatic charge image developing toner production method comprising producing an electrostatic charge image developing toner in an amount of 2 to 20 parts by weight.

[In the general formula (1), R ₁ , R ₂ and R ₃ are groups or atoms selected from the group consisting of a substituted or unsubstituted acyl group and a hydrogen atom, and R ₁ , R ₂ And R ₃ represents an acyl group having a hydroxyl group as a substituent and having 10 to 28 carbon atoms. ]

<2>
<1> The ester compound is a triester compound in which R ₁ , R ₂ , and R ₃ are formed of the same acyl group having a hydroxyl group as a substituent and having 10 to 28 carbon atoms. The method for producing a toner for developing an electrostatic image described in 1.
<3>
<2> The method for producing a toner for developing an electrostatic charge image according to <2>, wherein a ratio of the triester compound in the ester compound is 90% or more.

<4>
The method for producing a toner for developing an electrostatic charge image according to any one of <1> to <3>, wherein the ester compound is hardened castor oil.

<5>
The electrostatic image developing toner production method according to any one of <1> to <4>, wherein the electrostatic image developing toner contains a release agent,
The release agent is at least one selected from carnauba wax, montan wax, rice wax, and synthetic ester wax;
The method for producing a toner for developing an electrostatic charge image, wherein the release agent is contained in an amount of 2 to 30 parts by weight with respect to 100 parts by weight of the amorphous polyester resin.

<6>
The electrostatic charge image according to any one of <1> to <5>, wherein a loss tangent (tan δ) of the toner for electrostatic image development is in a range of 0.050 to 0.100. This is a developing toner manufacturing method .

According to the present invention as described above, can be low-temperature fixing together it is possible, to provide sufficient chargeability and storability producing how the toner over the electrostatic image developing having.

  Hereinafter, the present invention will be described in the order of an electrostatic image developing toner, a method for producing an electrostatic image developing toner, an electrostatic image developing developer, and an image forming method.

<Toner for electrostatic image development>
The toner for developing an electrostatic image obtained by the production method of the present invention (hereinafter sometimes abbreviated as “toner”, “the toner of the present invention” or “the toner for developing an electrostatic image of the present invention” ) is an amorphous polyester. In the toner for developing an electrostatic charge image containing a resin and a colorant, 2 to 20 parts by weight of an ester compound represented by the following general formula (1) is included with respect to 100 parts by weight of the amorphous polyester resin. It is characterized by that.

However, in the general formula (1), R ₁ , R ₂ and R ₃ are substituted or unsubstituted acyl groups (hereinafter sometimes abbreviated as “acyl groups” regardless of whether they are substituted) and hydrogen atoms And at least one of R ₁ , R _2, and R ₃ represents an acyl group having a hydroxyl group as a substituent and having 10 to 28 carbon atoms.

The ester compound represented by the general formula (1) (hereinafter sometimes abbreviated as “ester compound”) is generally used as a release agent for toner, but has been studied by the present inventors. However, it has been found that by combining with an amorphous polyester resin as a toner, low-temperature fixing is possible, and it is easy to obtain sufficient chargeability and excellent storage stability. There are three reasons for this.
That is, first, the ester compound used in the present invention is generally incompatible with a binder resin such as a vinyl resin used in a toner, but with respect to an amorphous polyester resin. Is considered to be due to the excellent compatibility and the effect of acting as a plasticizer. For this reason, even a toner using an amorphous polyester resin that is originally not suitable for low-temperature fixing can be fixed at low temperature.
In addition, secondly, in the present invention, an amorphous polyester resin is used as the binder resin, and the crystalline resin is not necessarily used. Therefore, it is possible to prevent the deterioration of the charging characteristics that are easily generated with the toner using the crystalline resin.
Thirdly, the amorphous polyester resin itself is superior in heat resistance as compared with a general crystalline resin used in toner, and therefore is excellent in toner storability and document storability in a high temperature environment.

However, in order to achieve both low-temperature fixability and storage stability, the ester compound contained in the toner should contain 2 parts by weight or more with respect to 100 parts by weight of the amorphous polyester resin contained in the toner. is required.
When the amount is less than 2 parts by weight, the plasticizing effect of the ester compound on the amorphous polyester resin is not sufficient, and low-temperature fixing becomes impossible. From the viewpoint of securing low temperature fixability, the content of the ester compound with respect to 100 parts by weight of the amorphous polyester resin contained in the toner is preferably 3 parts by weight or more, and preferably 4 parts by weight or more. Is more preferable.
On the other hand, when the content is too large, the glass transition point of the toner is excessively lowered, so that the storage stability such as toner blocking and the document storage property of the printed matter on which the image is formed are insufficient. For this reason, the content needs to be 20 parts by weight or less, and preferably 15 parts by weight or less.

  In the toner of the present invention, an amorphous polyester resin is always used as a binder resin, but other binder resins can be used in combination. In this case, the amount of the amorphous polyester resin in the total binder resin is preferably at least 50% by weight, more preferably 60% by weight. If the amount is less than 50% by weight, even if an ester compound is used, the overall plasticization of the binder resin component becomes insufficient, so that low-temperature fixing may not be possible.

  In addition, a crystalline resin may be used in combination as long as the charging property is not adversely affected. In this case, the ratio of the crystalline resin in the total binder resin is preferably 40% by weight or less, and more preferably 30% by weight or less. When the proportion of the crystalline resin exceeds 40% by weight, the chargeability may be insufficient. Further, even if a small amount of the crystalline resin is present, it may be insufficient when it is exposed on the surface of the toner. Therefore, the crystalline resin is preferably contained in the toner. In order to realize such a structure in which a crystalline resin is contained inside the toner, a toner having a so-called core-shell structure manufactured using an emulsion polymerization aggregation method can be used.

  The toner of the present invention is not particularly limited as long as it contains an amorphous polyester resin, a colorant, and an ester compound, but if necessary, a binder resin other than the amorphous polyester resin, A mold release agent and other additives may be contained. Hereinafter, various materials constituting the toner of the present invention and preferable properties of the toner will be described in more detail.

-Ester compound-
As described above, the ester compound represented by the general formula (1) is used in the present invention. Here, to demonstrate the compatibility with the amorphous polyester resin, in order to function as a plasticizer, R _1, R _2, and at least one of R _3, an acyl group having a carbon number is 10 to 28 It is necessary to be. In addition, as for carbon number of an acyl group, it is more preferable that it is 12-28, and it is still more preferable that it is 12-24.

When any of the acyl groups constituting R ₁ , R ₂ , and R ₃ has less than 10 carbon atoms, the toner is plasticized more than necessary, and the storage stability of the toner is deteriorated. This increases the loss tangent of the battery and deteriorates the chargeability.
On the other hand, when the carbon number of any acyl group constituting R ₁ , R ₂ and R ₃ is outside the range of 10 to 28 and the carbon number of at least one of the acyl groups exceeds 28, an ester Since the embedding property of the compound in the toner is remarkably lowered, the action as a plasticizer becomes insufficient.

Further, the acyl group needs to have a hydroxyl group from the viewpoint of compatibility with the amorphous polyester resin.
Furthermore, it is more preferable that any of R ₁ , R ₂ , and R ₃ is an acyl group because the compatibility with the amorphous polyester resin is improved and the action as a plasticizer is further enhanced. _{When 1} , R ₂ and R ₃ are acyl groups, the structures of these three acyl groups are more preferably the same.
Moreover, it is preferable that the ratio of the triester compound (namely, ester compound in which all of R < ₁ >, R < ₂ > and R < ₃ > are acyl groups) contained in an ester compound is 90% or more. Since the triester compound is more compatible with the amorphous polyester resin than the diester compound or the monoester compound, the plasticization of the toner is made more effective, and the low-temperature fixability is further increased.

On the other hand, when forming an image using an intermediate transfer body, when a full-color image is formed, the toner image laminated and transferred onto the intermediate transfer body becomes extremely thick, which makes transfer difficult and reduces transfer efficiency. There is. In order to suppress such a decrease in transfer efficiency, it is necessary that the surface of the toner used has high smoothness.
In contrast, the toner of the present invention produced by combining an ester compound and an amorphous polyester resin can improve the surface smoothness. Therefore, high image transfer efficiency can be obtained even when forming an image using an intermediate transfer member.

  In particular, when the toner of the present invention is produced using an emulsion polymerization aggregation method described later, the ester compound is easily included in the toner as a plasticizer. Furthermore, in the emulsion polymerization aggregation method, precipitation of the ester compound on the toner particle surface is suppressed particularly in the step of fusing the aggregated particles, so that the smoothness of the finally obtained toner surface can be further improved. . Also, when a triester compound is used as the ester compound, the compatibility with the amorphous polyester resin is excellent, and therefore the smoothness of the toner surface can be further improved.

As the ester compound, known ester compounds can be used as long as they satisfy the structure represented by the general formula (1). Preferred compounds include 12 -hydroxystearic acid triglyceride, hardened castor oil, and the like. These ester compounds may be used alone or in combination. In addition, examples of the ester compound that does not have the structure represented by the general formula (1) include glycerin tripaltimitate and glycerin tribehenate.
In addition, as an ester compound used for this invention, hardened castor oil is especially preferable. Hardened castor oil is a triester compound, and since the structure of the three acyl groups is the same and the acyl group has a hydroxyl group, it is extremely excellent in compatibility with the amorphous polyester resin and has a more plasticizing effect. This is because it can be expected.

-Binder resin: Amorphous polyester resin-
The amorphous polyester resin that is always used in the toner of the present invention is synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present invention, a commercially available product may be used as the amorphous polyester resin, or an appropriately synthesized product may be used.
In addition, the type and combination of the polyvalent carboxylic acid component and polyhydric alcohol component used in the synthesis, and the synthesis conditions are appropriately selected so that the resulting polyester resin is amorphous.

Examples of polyvalent carboxylic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, maleic anhydride, fumaric acid, succinic acid, alkenyl. Examples thereof include aliphatic carboxylic acids such as succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination. Of these polyvalent carboxylic acids, it is preferable to use aromatic carboxylic acids, and in order to take a crosslinked structure or a branched structure in order to ensure good fixability, tricarboxylic or higher carboxylic acids (trimerits) An acid or an acid anhydride thereof may be used in combination.

Moreover, as an acid component, it is preferable that the dicarboxylic acid component which has a sulfonic acid group other than the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid is contained. The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a colorant such as a pigment.
Further, when a resin particle is produced by emulsifying or suspending the entire binder resin in water and the toner of the present invention is produced using the resin particle, a surface activity can be obtained by using a dicarboxylic acid component having a sulfonic acid group. Emulsification or suspension is possible without using any agent.

Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt.
Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. The divalent or higher carboxylic acid component having a sulfonic acid group is contained in an amount of 1 to 15 mol%, preferably 2 to 10 mol%, based on all carboxylic acid components constituting the polyester. When the content is low, the temporal stability of the emulsified particles may be deteriorated.
On the other hand, if it exceeds 15 mol%, not only will the process of coalescence of particles after agglomeration be adversely affected, it will be difficult to adjust the toner diameter, but there may be a problem that the chargeability of the toner will be adversely affected.

  Furthermore, in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid, a dicarboxylic acid component having a double bond may be contained. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of such dicarboxylic acids include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, and other aliphatic diols, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A And aromatic diols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct. One or more of these polyhydric alcohols can be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. In order to secure good fixing properties, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

In addition, a monocarboxylic acid and / or a monoalcohol is further added to the amorphous polyester resin obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol, and a hydroxyl group and / or a carboxyl group at the polymerization terminal is added. May be esterified to adjust the acid value of the amorphous polyester resin.
Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride and the like, and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, and trifluoroethanol. , Trichloroethanol, hexafluoroisopropanol, phenol and the like.

  The amorphous polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C. to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

  Examples of the catalyst used for the synthesis of the amorphous polyester resin include esterification catalysts such as organic metals such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutyl titanate. The amount of such a catalyst added is preferably 0.01 to 1% by weight based on the total amount of raw materials.

  The amorphous polyester resin used in the toner of the present invention has a weight average molecular weight (Mw) of 4,000 to 100,000, as measured by a gel permeation chromatography (GPC) method in which tetrahydrofuran (THF) is soluble. More preferably, it is 5000-80000, the number average molecular weight (Mn) is preferably 2000-30000, the molecular weight distribution Mw / Mn is preferably 2-50, more preferably 2-20. It is.

When the weight average molecular weight and the number average molecular weight are smaller than the above ranges, while being effective for low temperature fixability, not only the hot offset resistance is remarkably deteriorated, but also the glass transition point of the toner is lowered. The storage stability such as toner blocking may be adversely affected.
On the other hand, when the molecular weight is larger than the above range, the hot offset resistance can be sufficiently provided, but the low-temperature fixability may be lowered. Therefore, it becomes easy to satisfy both the low-temperature fixability, the hot offset resistance, and the document storage stability by satisfying the above conditions.

  In the present invention, the molecular weight of the binder resin is determined by measuring THF solubles using a THF solvent using GPC / HLC-8120 manufactured by Tosoh Corporation and a column / TSKgel SuperHM-M manufactured by Tosoh Corporation (15 cm). This is a molecular weight calculated using a molecular weight calibration curve prepared from a sample.

The acid value of the amorphous polyester resin (mg number of KOH required to neutralize 1 g of resin) can be easily obtained from the molecular weight distribution as described above, and the toner of the present invention can be obtained using an emulsion polymerization aggregation method. 1-30 mgKOH because it is easy to ensure granulation in the production, and it is easy to maintain the environmental stability (stability of chargeability when the temperature and humidity change) of the obtained toner. / G is preferable.
The acid value of the amorphous polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester by the blending ratio and reaction rate of the raw material polycarboxylic acid and polyhydric alcohol. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

  The glass transition temperature of the amorphous polyester resin used in the present invention is preferably 55 to 100 ° C., and more preferably 55 to 80 ° C. from the viewpoint of the balance between storage stability and toner fixing property. preferable. When the glass transition temperature is less than 55 ° C., the toner tends to easily block during storage or in the developing machine (a phenomenon in which toner particles are aggregated into a lump). On the other hand, if the glass transition temperature exceeds 100 ° C., the toner fixing temperature may increase.

-Colorant-
The colorant used in the toner of the present invention is not particularly limited as long as it is a known colorant. For example, carbon black such as furnace black, channel black, acetylene black, thermal black, bengara, bitumen, titanium oxide, etc. Inorganic pigments, fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, para brown and other azo pigments, copper phthalocyanine, metal-free phthalocyanine and other phthalocyanine pigments, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, Examples thereof include condensed polycyclic pigments such as dioxazine violet.

  Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrarozone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxalate, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment 57: 1, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Examples thereof include various pigments such as CI Pigment Blue 15: 3, and these can be used alone or in combination of two or more.

The content of the colorant in the toner of the present invention is preferably 1 to 30 parts by weight, more preferably 1 to 10% by weight, and more preferably 2 to 10% by weight with respect to 100 parts by weight of the binder resin. More preferably, it is 2 to 7% by weight, and it is preferably as much as possible as long as the smoothness of the image surface after fixing is not impaired. When the content of the colorant is increased, the thickness of the image can be reduced when an image having the same density is obtained, which is advantageous in terms of prevention of offset.
It is also effective to use a surface-treated colorant or a pigment dispersant as necessary. By appropriately selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

-Release agent-
A release agent can be used in the toner of the present invention as necessary. In addition, in the present invention, the ester compound represented by the general formula (1) has a stronger action as a plasticizer than an action as a release agent. Therefore, it is particularly preferable to use a separate release agent.
In this case, the release agent used in the toner of the present invention is not particularly limited as long as it is a known release agent. For example, natural waxes such as carnauba wax, rice wax, and candelilla wax, low molecular weight polypropylene, Synthesis of low molecular weight polyethylene, sazol wax, microcrystalline wax, Fischer-Tropsch wax, paraffin wax, montan wax, etc. or mineral-petroleum wax, fatty acid ester, ester wax such as montanic acid ester, etc. It is not limited. Moreover, these mold release agents may be used individually by 1 type, and may be used together 2 or more types.

In particular, among the release agents described above, it is preferable to use at least one release agent selected from carnauba wax, montan wax, rice wax, and synthetic ester wax, which has low compatibility with the amorphous polyester resin.
The release agent is preferably contained in an amount of 2 to 30 parts by weight per 100 parts by weight of the binder resin. When the content of the release agent is less than 2 parts by weight, the effect on hot offset resistance at high temperature fixing may be insufficient.
On the other hand, if the amount exceeds 30 parts by weight, the charging property is adversely affected, and the mechanical strength of the toner is reduced. May cause. Further, when used as a color toner, there are cases where a domain tends to remain in a fixed image and OHP transparency is deteriorated. In addition, when the toner of the present invention is produced by an emulsion polymerization aggregation method described later, there is a strong tendency that the obtained toner has a broad particle size distribution.

  The melting point of the release agent is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of storage stability. Moreover, it is preferable that it is 110 degrees C or less from a viewpoint of offset resistance, and it is more preferable that it is 100 degrees C or less.

-Other additives-
In addition to the components described above, various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles can be added to the toner of the present invention as necessary. .
Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.

Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.
The inorganic powder is added mainly for the purpose of adjusting the viscoelasticity of the toner. For example, silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, etc. Examples include all inorganic particles used as an external additive on the toner surface.

Examples of inorganic particles and organic particles externally added to the toner surface include the following.
Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, silica particles and titanium oxide particles are preferable, and hydrophobically treated particles are particularly preferable.

Inorganic particles are generally used for the purpose of improving fluidity. The primary particle diameter of the inorganic particles is preferably 1 to 200 nm, and the addition amount is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the toner.
Organic particles are generally used for the purpose of improving cleaning properties and transfer properties, and specific examples include polystyrene, polymethyl methacrylate, polyvinylidene fluoride, and the like.

-Various properties of toner-
The toner of the present invention has a volume average particle size of preferably 1 to 20 μm, more preferably 2 to 8 μm, and a number average particle size of 1 to 20 μm is preferable and 2 to 8 μm is more preferable.
The volume average particle diameter and the number average particle diameter can be measured, for example, by measuring with a 50 μm aperture diameter using a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

The loss tangent (tan δ) of the toner of the present invention is preferably 0.05 to 0.10. The loss tangent of the toner is a characteristic that greatly affects the chargeability, developability, and transferability, but when the loss tangent of the toner is less than 0.05, there is no problem with the chargeability, but the toner concentration in the developer When the temperature rises or under low temperature and low humidity, the resistance as a developer increases, and the gradation of the image may deteriorate or fog may occur in the background portion. On the other hand, when the loss tangent of the toner exceeds 0.10, there may be a problem that the charge amount after being left is lowered or the transferability is deteriorated due to charge injection.
In addition, when an image is formed using an intermediate transfer member, if the loss tangent (tan δ) is out of the above range, toner scattering and line image bleeding may occur.

<Method for producing toner for developing electrostatic image>
The toner production method of the present invention is carried out by an emulsion polymerization aggregation method .

The details of the toner production method of the present invention will be described below.
In the toner of the present invention, (1) at least an amorphous polyester resin, a colorant, and an ester compound (shown by the general formula (1)) are each dispersed in an aqueous medium to obtain a resin particle dispersion and a colorant dispersion. An emulsifying step of adjusting the liquid and the ester compound dispersion; (2) an aggregating step of forming aggregated particles in a raw material dispersion containing the resin particle dispersion, the colorant dispersion, and the ester compound dispersion; ) It can be produced through at least a fusing step of fusing the aggregated particles by heating.
In addition, as various dispersion liquid adjusted by an emulsification process, the resin particle dispersion liquid etc. which contain a mold release agent dispersion liquid and binder resin as needed can be utilized.
In addition, a coating that covers the surface of the aggregated particles obtained in the aggregation step or the particles obtained after the fusion obtained in the fusion step with resin particles having the same or different composition as the binder resin contained in the aggregated particles, if necessary. A process may be provided. In the latter case, the fusion process is performed again after the coating process.
Hereinafter, each step will be described in detail.

-Emulsification process-
Various raw materials constituting the toner, such as a binder resin, a colorant, and an ester compound, are used in the state of each emulsified particle in an aggregation process and a coating process that is performed as necessary. For this reason, in the emulsification step performed prior to the aggregation step, the above-described emulsified dispersion (resin particle dispersion, colorant dispersion, ester compound dispersion, etc.) is adjusted. In addition, when using binder resin other than an amorphous polyester resin as binder resin, the resin particle dispersion liquid which consists of this binder resin can also be adjusted.

  The volume average particle diameter of the resin particles made of the binder resin is usually 1 μm or less, and preferably 0.01 to 1 μm. When the volume average particle size exceeds 1 μm, the particle size distribution of the finally obtained toner is broadened and free particles are generated, which tends to cause a decrease in toner performance and reliability. On the other hand, when the volume average particle size is within the above range, there are no disadvantages, and it is advantageous in that uneven distribution among toners is reduced, dispersion in the toner is improved, and variations in performance and reliability are reduced. . The volume average particle diameter can be measured using, for example, a Coulter counter.

An aqueous medium is used as a dispersion medium in the dispersion. Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together.
In the present invention, it is preferable to add and mix a surfactant in the aqueous medium. Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like. Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.

On the other hand, it is preferable that the resin particle which consists of an amorphous polyester resin contains the hydrophilic functional group which can become an anion type by neutralization. In this case, since the polyester resin in which part or all of the functional groups are neutralized with a base has self-dispersibility with respect to water, a stable aqueous dispersion can be formed under the action of an aqueous medium.
In the polyester resin, functional groups that show hydrophilicity upon neutralization are mainly acidic groups such as carboxyl groups and sulfone groups, and examples of neutralizing agents include sodium hydroxide, potassium hydroxide, lithium hydroxide, and hydroxide. Examples include inorganic bases such as calcium, sodium carbonate, and ammonia, and organic bases such as diethylamine, triethylamine, and isopropylamine.

In the case of preparing a dispersion using an amorphous polyester resin that does not disperse in water as a binder resin, that is, does not have self-water dispersibility, it is amorphous as in a release agent described later. Dispersed in a solution containing a reactive polyester resin and / or an aqueous medium mixed therewith with a polymer electrolyte such as an ionic surfactant, polymer acid, polymer base, etc., and heated to a temperature higher than the glass transition point of the amorphous polyester resin However, it is preferable to perform the treatment using a homogenizer or a pressure discharge type disperser capable of applying a strong shearing force. Thereby, the volume average particle diameter of the resin particles in the obtained resin particle dispersion can be easily reduced to 1 μm or less.
When an ionic surfactant or polymer electrolyte is used, the concentration in the aqueous medium is suitably about 0.5 to 5% by weight.

As the colorant used for preparing the colorant dispersion, the colorants described above can be used.
As a method for dispersing the colorant, any method, for example, a general dispersion method such as a rotary shear homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and the colorant is not limited at all. If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant, or an organic solvent dispersion of these colorants can be prepared using a dispersant.
As the surfactant and the dispersing agent used for dispersion, the same dispersing agents that can be used when dispersing the binder resin can be used.
Further, the colorant may be added to the mixed solvent at one time together with other particle components, or may be divided and added in multiple stages.

As the ester compound used in the ester compound dispersion, the ester compound described above can be used.
As a method for dispersing the ester compound, as in the case of emulsifying and dispersing an amorphous polyester resin having no self-water dispersibility, it is dispersed in water together with an ionic surfactant or the like, or a surfactant is not used. The volume average particle diameter is adjusted to 1 μm or less using a homogenizer or pressure discharge type disperser that can be heated to the melting point of the ester compound as it is and can apply a strong shearing force. As the dispersion medium in the ester compound dispersion, the same dispersion medium as that for the binder resin can be used.

In preparation of the toner, a release agent dispersion can be used, and the release agent described above can be used as the release agent to be emulsified and dispersed.
The release agent can be dispersed in water together with an ionic surfactant, etc. in the same way as when emulsifying and dispersing an amorphous polyester resin that does not have self-water dispersibility. The volume average particle size of the dispersed release agent particles is adjusted to 1 μm or less using a homogenizer or a pressure discharge type disperser. As the dispersion medium in the release agent dispersion, the same dispersion medium as that of the binder resin can be used.

  In the present invention, as an apparatus for mixing and emulsifying and dispersing raw material components such as a binder resin, a colorant and an ester compound with an aqueous medium, for example, a homomixer (Special Machine Industries Co., Ltd.) or a slasher (Mitsui Mine Co., Ltd. ), Cavitron (Eurotech Co., Ltd.), Microfluidizer (Mizuho Kogyo Co., Ltd.), Menton Gorin homogenizer (Gorin Co., Ltd.), Nanomizer (Nanomizer Co., Ltd.), Static Mixer (Noritake Company), etc. Machine.

  The content of the particle components (binder resin, colorant, release agent) contained in the resin particle dispersion, colorant dispersion and release agent dispersion is usually 5 to 50% by weight, preferably 10 to 10%. 40% by weight. When the content is out of the above range, the particle size distribution of the obtained toner may be widened and the characteristics may be deteriorated.

In the present invention, other components such as the internal additive, the charge control agent, and the inorganic powder as described above may be dispersed in the resin particle dispersion according to the purpose.
The charge control agent in the present invention is preferably a material that is difficult to dissolve in water in terms of controlling ionic strength that affects the stability of the aggregation process and the fusion process and reducing wastewater contamination.

  The volume average particle size of the other components is usually 1 μm or less, preferably 0.01 to 1 μm. If the average diameter exceeds 1 μm, the particle size distribution of the finally obtained toner may be broadened, or free particles may be generated, which may lead to a decrease in performance and reliability. On the other hand, when the volume average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toner is good, and the variation in performance and reliability is reduced.

-Aggregation process-
In the aggregation step, the resin particle dispersion obtained in the emulsification step, the colorant dispersion, the ester compound dispersion, and various other dispersions such as a release agent dispersion used as necessary. Mixed liquid mixture (hereinafter, this liquid mixture is referred to as “raw material dispersion”), a temperature not higher than the melting point of the ester compound (in the case where a release agent dispersion is used, a temperature not higher than the melting point of the release agent or the ester compound). By heating, aggregated particles are formed by aggregating the respective particles.

The formation of the agglomerated particles is performed through the following two steps. First, after removing the ester compound dispersion and acidifying the pH of the raw material dispersion obtained by mixing each dispersion, the flocculant is added at room temperature with high-speed stirring using a rotary shearing homogenizer. Then, the flocculant is uniformly dispersed in the raw material dispersion thickened by the initial aggregation.
Then the second step, stirring by stirring blades to the raw material dispersion liquid is thickened, ester compound dispersion is added and heated gradually and dispersed uniformly. Aggregated particles are formed through these two stages. In addition, as pH in this case, 2.5-6 are preferable and 3-6 are more preferable.

  On the other hand, when an amorphous polyester resin having self-water dispersibility containing a functional group that can be converted into an anionic form by neutralization is used as a binder resin, the emulsion dispersion of the amorphous polyester resin before adjusting the raw material dispersion The pH of the liquid is 7-8. For this reason, if the colorant dispersion having a pH of 3 to 5 or a release agent dispersion used as necessary is mixed or adjusted to the above pH for aggregation, the balance of polarity is lost, and the loose aggregation Will occur. Therefore, when the pH of the amorphous polyester resin dispersion (1) is on the alkali side, after adding a surfactant in advance at room temperature to allow the surfactant to blend into the surface of the resin particles, the colorant dispersion Mix etc.

  As the aggregating agent used in the aggregating step, a surfactant having a polarity opposite to that of the surfactant used for the dispersing agent, an inorganic metal salt, or a divalent or higher-valent metal complex can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

  In the aggregation step, in order to suppress rapid aggregation due to heating, the pH may be adjusted while stirring and mixing at room temperature, and a dispersion stabilizer may be added as necessary.

In the final toner, for the purpose of further improving the chargeability and powder flowability, it is preferable to carry out the coating step after the aggregation step.
This coating step is a step of forming a coating layer by adhering resin particles having the same or different composition as the binder resin constituting the aggregated particles to the above-mentioned aggregated particle surface.

  The coating layer can be formed by additionally adding the resin particle dispersion to the raw material dispersion containing the aggregated particles obtained after the aggregation step, and additionally adding other dispersions at the same time as necessary. May be. Also in the coating process, the pH and surfactant were selected according to the composition of the resin particles to be used in the same manner as in the aggregation process, and the coating layer was formed taking care not to unevenly adhere the resin particles to the surface of the aggregated particles. Aggregated particles (coated aggregated particles) are obtained. This coating step is also effective in guiding raw material particles that have not been taken into the aggregated particles in the aggregation step. In addition, a coating process can also be implemented with respect to the particle | grains obtained after uniting the aggregated particle.

-Fusion process-
In the fusion step, the progress of aggregation was stopped by adjusting the pH of the suspension containing aggregated particles (or coated aggregated particles) to a range of 7.5 to 9.5 under the same stirring as in the aggregation step. Thereafter, the aggregated particles (or coated aggregated particles) are fused by heating at a temperature equal to or higher than the glass transition point or the melting point of the binder resin (however, the melting point is when the crystalline resin is used in combination). Depending on the liquidity of the dispersion containing the aggregated particles, if the pH at which aggregation is stopped is not appropriate, the aggregated particles may be dispersed during the temperature rising process for coalescence, resulting in a poor yield or vice versa. In some cases, the aggregation cannot be stopped, and the particle size growth further proceeds, resulting in a large particle size.

  There is no problem if the heating temperature at the time of fusion is not less than the glass transition temperature (or melting point) of the binder resin contained in the aggregated particles. The heating time may be as long as sufficient fusion is achieved, and is preferably performed for about 0.5 to 3 hours. When heating is performed for 3 hours or more, when a release agent is used, the release agent contained in the aggregated particles is likely to be exposed on the surface of the toner. In this case, although effective in terms of fixability, it may adversely affect the storage stability of the toner.

  In the fusion step, a crosslinking reaction may be performed when the binder resin is heated to a glass transition temperature (or melting point) or higher, or after the fusion is completed. In addition, a crosslinking reaction can be performed simultaneously with the fusion. When the crosslinking reaction is performed, for example, an unsaturated sulfonated amorphous polyester resin obtained by copolymerizing a double bond component is used as a binder resin, and a radical reaction is caused to the resin to introduce a crosslinked structure. . At this time, the following polymerization initiator is used.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxyca) Bonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydrotereph Tartrate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the binder resin and the type and amount of the coexisting colorant.
The polymerization initiator may be previously mixed in the binder resin before the emulsification step, or may be incorporated into the aggregated particles in the aggregation step. Furthermore, it may be introduced after the coating step, the fusion step, or the fusion step.
In the case of introduction after the aggregation step, coating step, fusion step, or fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a particle dispersion (resin particle dispersion or the like). These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

  The fused particles obtained by fusing can be made into toner particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to sufficiently wash in the washing step.

  In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. It is desirable that the toner particles have a moisture content after drying of 1.0% by weight or less, preferably 0.5% by weight or less.

  As described above, various known external additives such as inorganic particles and organic particles as described above can be added to the toner particles granulated through the drying step as described above according to the purpose.

<Developer for developing electrostatic image>
The electrostatic image developing toner of the present invention is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, it is used by mixing with a carrier.
There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.

Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable.
The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in a coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (weight ratio) of the toner of the present invention and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 to 30: 100, and about 3: 100 to 20: 100. A range is more preferred.

<Image forming method>
The image forming method of the present invention is not particularly limited as long as it uses the toner of the present invention. Specifically, the latent image forming step of forming an electrostatic latent image on the surface of the latent image carrier, and the latent image A developing step of developing the electrostatic latent image formed on the surface of the carrier with the developer containing the toner of the present invention to form a toner image, and the toner image formed on the surface of the latent image carrier on the surface of the recording medium It is particularly preferable that the image forming method includes a transfer step of transferring and a fixing step of thermally fixing the toner image transferred to the surface of the recording medium.

The developer may be either a one-component system or a two-component system. As each of the above steps, a known step in the image forming method can be used. The image forming method of the present invention may include steps other than the steps described above.
For example, the transfer step includes a primary transfer step of transferring a toner image formed on the surface of the latent image carrier to an intermediate transfer member, and a secondary transfer step of transferring the toner image transferred onto the intermediate transfer member to a recording medium. It may consist of.
In the image forming apparatus using the intermediate transfer method, the toner images of the respective colors that are superimposed and transferred onto the latent image carrier are collectively transferred to the recording medium. In addition to printing paper called paper, it has the advantage that images can be formed on thick paper and envelopes, and it has a structure in which an intermediate transfer belt is stretched by a plurality of rolls. There is an advantage that routing can be performed relatively freely and the size of the apparatus can be reduced. In addition, when the toner of the present invention is used in combination, high transfer efficiency can be obtained as described above.

As the latent image carrier, for example, an electrophotographic photosensitive member and a dielectric recording member can be used.
In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step). Next, the toner particles are adhered to the electrostatic latent image by contacting or approaching a developing roll having a developer layer formed on the surface to form a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a recording medium such as paper using a corotron charger or the like (transfer process). Further, the toner image transferred to the surface of the recording medium is heat-fixed by a fixing device to form a final toner image.
In the heat fixing by the fixing device, a release agent is usually supplied to a fixing member in the fixing device in order to prevent offset and the like.

  In the toner of the present invention (including those contained in the two-component developer, the same applies hereinafter), when the binder resin has a cross-linked structure, it is excellent in releasability due to its effect and the amount of the release agent used. Fixing can be carried out without reducing or using a release agent.

The release agent is preferably not used from the viewpoint of eliminating oil adhesion to the recording medium and image after fixing. However, when the supply amount of the release agent is 0 mg / cm ² , the fixing member is used during fixing. When the sheet and a recording medium such as paper come into contact with each other, the amount of wear of the fixing member may increase and the durability of the fixing member may decrease. Is preferably supplied to the fixing member in a small amount within a range of 8.0 × 10 ⁻³ mg / cm ² or less.

When the supply amount of the release agent exceeds 8.0 × 10 ⁻³ mg / cm ² , the image quality deteriorates due to the release agent adhering to the image surface after fixing, and in particular, transmitted light like OHP is transmitted. When used, such a phenomenon may be noticeable. Further, the adhesion of the release agent to the recording medium becomes remarkable, and stickiness may occur. Further, the larger the supply amount of the release agent, the larger the capacity of the tank for storing the release agent, which causes an increase in the size of the fixing device itself.

  Although there is no restriction | limiting in particular as said mold release agent, For example, liquid mold release agents, such as modified oils, such as dimethyl silicone oil, fluorine oil, fluoro silicone oil, and amino modified silicone oil, are mentioned. Among these, modified oils such as amino-modified silicone oil are preferable because they are adsorbed on the surface of the fixing member and can form a homogeneous release agent layer, because they have excellent wettability to the fixing member. Further, from the viewpoint of forming a homogeneous release agent layer, fluorine oil and fluorosilicone oil are preferable.

  The use of fluorine oil or fluorosilicone oil as the release agent does not use the toner of the present invention. In the conventional image forming method, the supply amount of the release agent itself cannot be reduced. Although not practical in terms of use, when the toner of the present invention is used, since the supply amount of the release agent can be drastically reduced, there is no practical problem in terms of cost.

  The method for supplying the release agent to the surface of the roller or belt, which is a fixing member used for the thermocompression bonding, is not particularly limited. For example, a pad method using a pad impregnated with a liquid release agent, a web method, Examples thereof include a roller method and a non-contact type shower method (spray method). Among these, a web method and a roller method are preferable. These methods are advantageous in that the release agent can be supplied uniformly and it is easy to control the supply amount. In order to supply the release agent uniformly to the entire fixing member by the shower method, it is necessary to use a separate blade or the like.

The supply amount of the release agent can be measured as follows. That is, when a plain paper (typically, a copy paper manufactured by Fuji Xerox Co., Ltd., trade name J paper) used in a general copying machine is passed through a fixing member supplied with a release agent on its surface. The release agent adheres to the plain paper. The attached release agent is extracted using a Soxhlet extractor. Here, hexane is used as the solvent.
By quantifying the amount of the release agent contained in hexane with an atomic absorption analyzer, the amount of the release agent adhering to the plain paper can be quantified. This amount is defined as the amount of release agent supplied to the fixing member.

Examples of the recording medium (recording material) to which the toner image is transferred include plain paper, an OHP sheet, and the like used for electrophotographic copying machines and printers.
In order to further improve the smoothness of the image surface after fixing, the surface of the recording medium is preferably as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Can be preferably used.

  Since the image forming method of the present invention uses the developer of the present invention (the toner of the present invention), fixing at a low temperature is possible and the toner can maintain an appropriate charge amount. Therefore, it is excellent in energy saving at the time of image formation, and a good image can be formed while preventing the occurrence of toner scattering and the like.

  Next, an example of an image forming apparatus that can be used in the image forming method of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an intermediate transfer belt type color image forming apparatus that can be used in the image forming method of the present invention.
As shown in FIG. 1, the color image forming apparatus includes a photosensitive drum 1 (electrostatic latent image carrier) that rotates in the direction of arrow A.
Further, in order along the rotation direction of the photosensitive drum 1, a charging roll 11 for uniformly charging the surface of the photosensitive drum 1, and an electrostatic latent image by irradiating the charged photosensitive drum 1 surface with exposure light. And a developing device corresponding to each of the above-described colors that forms a toner image by developing the electrostatic latent image with yellow (Y), magenta (M), cyan (C), and black (Bk) toners. A rotary developing device 12 composed of 12Y, 12M, 12C, and 12Bk, a primary transfer roll 5 that is opposed to the intermediate transfer belt 2 and connected to a power source 5a, and toner remaining on the photosensitive drum 1 are removed. A photoconductor cleaner 14 is disposed.

Further, the endless belt-like intermediate transfer belt 2 has a tension roll 21, a primary transfer roll 5, a drive roll 22, and a backup roll 23 on its inner peripheral surface along the rotation direction indicated by the arrow B. Arranged in order and stretched by three rolls excluding the primary transfer roll 5, and can rotate in the direction of arrow B.
The intermediate transfer belt 2 is in contact with the photosensitive drum 1 to form the primary transfer portion T1, and the intermediate transfer belt 2 is also in contact with the secondary transfer roll 24 disposed opposite to the backup roll 23 on the outer peripheral surface. Part T2 is formed. Further, the recording medium P can be inserted between the secondary transfer roll 24 and the intermediate transfer belt 2 during image formation.

During image formation, the toner image formed on the photosensitive drum 1 is primarily transferred to the intermediate transfer belt 2 at the primary transfer portion T1, and the toner image on the intermediate transfer belt 2 is further transferred to the secondary transfer portion T2. The secondary transfer is performed on the recording medium P.
Further, on the inner peripheral surface of the intermediate transfer belt 2, a neutralizing brush 6 for discharging the intermediate transfer belt 2 from the inner peripheral surface side is disposed between the tension roll 21 and the primary transfer roll 5. An intermediate transfer belt cleaner 4 for removing toner remaining on the outer peripheral surface of the intermediate transfer belt 2 after the secondary transfer is provided on the outer peripheral surface of the transfer belt 2 in the vicinity of the drive roll 22.

  Next, each part will be described in more detail. In the primary transfer portion T1 where the photosensitive drum 1 and the intermediate transfer belt 2 are in contact with each other, the primary transfer roll 5 is pressed toward the photosensitive drum 1 on the back side of the surface of the intermediate transfer belt 2 that carries the toner image. A positive primary transfer high-voltage power supply is connected to the metal shaft of the primary transfer roll 5.

  A secondary transfer roll 24 is disposed at a position facing the backup roll 23 of the secondary transfer portion T2, and is installed so as to be able to contact with and separate from the intermediate transfer belt 2 by the action of the cam mechanism 25.

  The metal shaft portion of the secondary transfer roll 24 is connected to the ground, and the backup roll 23 is connected to a negative secondary transfer high-voltage power supply (not shown).

  The tension roll 21 is configured to keep the tension of the intermediate transfer belt 2 constant by a spring, and the drive roll 22 is connected to a motor (not shown) via a gear to drive the intermediate transfer belt 2. The backup roll 23 can be backed up by being disposed opposite to the secondary transfer roll 24.

In the case where one or more metal members are disposed on the moving path of the intermediate transfer belt 2 from the primary transfer portion T1 to the secondary transfer portion T2, the neutralizing brush 6 of the neutralization belt 6 of each of the metal members is disposed. It is desirable to arrange in the upstream in the rotation direction.
For example, when the tension roll 21 is made of stainless steel, the static elimination brush 6 is disposed on the upstream side in the rotation direction of the intermediate transfer belt 2 with respect to the tension roll 21 as shown in FIG.

  During image formation, when the intermediate transfer belt 2 passes through the primary transfer portion T1, charges are accumulated on the intermediate transfer belt 2 due to the influence of the primary transfer bias. Due to this charge, the multicolor toner image transferred onto the intermediate transfer belt 2 scatters from the intermediate transfer belt 2 when reaching the position before the installation position of the stainless steel tension roll 21, for example. Therefore, in the image forming apparatus according to the present embodiment, the neutralizing brush 6 that contacts the back surface of the intermediate transfer belt 2 is provided in front of the installation position of the tension roll 21 on the moving path of the intermediate transfer belt 2. The brush 6 allows the charges of the intermediate transfer belt 2 accumulated during the primary transfer and not released to escape to the ground.

  In this color image forming apparatus, the surface of the photosensitive drum 1 charged by the charging roll 11 is irradiated with exposure light based on image information by the exposure device 3 to form an electrostatic latent image. Each toner image of yellow (Y), magenta (M), cyan (C), and black (Bk) is formed by being developed by each color developer of the developing device 12.

  The toner images of these colors are electrostatically transferred one on top of the intermediate transfer belt 2 at the primary transfer portion T1 formed by the contact portion between the photosensitive drum 1 and the intermediate transfer belt 2 to form a multicolor toner image. Thereafter, the intermediate transfer belt 2 sandwiched between the backup roll 23 and the secondary transfer roll 24 that are arranged so as to be pressed against each other, and the secondary transfer section T2 that is a contact portion between the secondary transfer roll 24 and the intermediate transfer belt 2 The recording medium P is supplied to the secondary transfer portion T2 at the timing when the multicolor toner image is conveyed, and the multicolor toner image on the intermediate transfer belt 2 is transferred to the recording medium P all at once. After the transfer, fixing is performed by a fixing unit (not shown) to complete a color image.

In the image forming method of the present invention, as described above, the surface resistivity of the intermediate transfer member is 10 ⁹ Ω / cm to 10 ¹³ Ω / cm ² , and the volume resistivity is 10 ⁷ Ω · cm to 10 ¹³ Ω. -It is preferable that it is cm.
For example, when the image forming apparatus shown in FIG. 1 is described as an example, when the surface resistivity and the volume resistivity are lower than the above ranges, the secondary transfer current is transmitted through the intermediate transfer belt 2 (intermediate transfer member). Since it flows into the primary transfer portion T1, the primary transfer efficiency may deteriorate.
On the other hand, when the surface resistivity and volume resistivity are higher than the above ranges, there are the following problems. That is, while the intermediate transfer belt 2 charged at the time of primary transfer moves from the primary transfer portion T1 toward the secondary transfer portion T2, the charge amount of the intermediate transfer belt 2 is not sufficiently attenuated before the tension roll 21 is applied. When approaching, a discharge occurs in a minute gap between the intermediate transfer belt 2 and the tension roll 21.
Due to the influence of this discharge, image disturbance occurs in the toner image transferred to the intermediate transfer belt 2, and an image quality defect called white streak is caused. Accordingly, in order to obtain a good image without image quality defects, it is preferable that the surface resistivity and volume resistivity of the intermediate transfer belt 2 are in the above-described ranges.
In order to more reliably prevent the above-described image quality defects, it is preferable that the loss tangent (tan δ) of the toner of the present invention is in the range of 0.050 to 0.100.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following description, “parts” means “parts by weight”.
-Preparation of Amorphous Polyester Resin Dispersion (1)-
-Bisphenol A ethylene oxide 2 mol adduct: 50 mol%
-Bisphenol A propylene oxide 2 mol adduct: 50 mol%
・ Fumaric acid: 50 mol%
・ Terephthalic acid: 50 mol%
Ti (OBu) ₄ : 0.01 mol%
After the above raw materials were put into a heat-dried three-necked flask, the air in the container was depressurized by a depressurization operation, and was further brought into an inert atmosphere with nitrogen gas, and refluxed at 180 ° C. for 5 hours with mechanical stirring. Then, vacuum distillation was performed, the temperature was gradually raised to 230 ° C., and the mixture was stirred for 2 hours. When the mixture became viscous, the molecular weight was confirmed by GPC. A polyester resin was obtained. In addition, when this polyester resin was measured by DSC (Differential scanning calorimeter, Shimadzu Corporation make, DSC60), the glass transition point was 64 degree | times, melting | fusing point was not observed and it turned out that it is amorphous.

Subsequently, this was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with 0.37 wt% diluted ammonia water diluted with ion-exchanged water with reagent-exchanged water, and heated at 120 ° C with a heat exchanger at a rate of 0.1 liter per minute. The polyester resin melt was transferred to the Cavitron (manufactured by Eurotech Co., Ltd.). In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 Kg / cm ² , and a non-binding property containing particulate amorphous polyester resin (1) having a volume average particle size of 0.23 μm. A polyester resin dispersion (1) (resin particle concentration: 20% by weight) was obtained.

-Preparation of Amorphous Polyester Resin Dispersion (2)-
-Bisphenol A ethylene oxide 2 mol adduct: 67 mol%
-Bisphenol A propylene oxide 2 mol adduct: 33 mol%
・ Terephthalic acid: 50 mol%
・ Isophthalic acid: 50 mol%
Ti (OBu) ₄ : 0.01 mol%
After the above raw materials were put into a heat-dried three-necked flask, the air in the container was depressurized by a depressurization operation, and was further brought into an inert atmosphere with nitrogen gas, and refluxed at 180 ° C. for 5 hours with mechanical stirring.
Then, vacuum distillation was performed, the temperature was gradually raised to 230 ° C., and the mixture was stirred for 3 hours. When the mixture became viscous, the molecular weight was confirmed by GPC. A polyester resin was obtained.
When this polyester resin was measured by DSC, the glass transition point was 66 degrees, the melting point was not observed, and it was found to be amorphous.

Subsequently, this was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with 0.37% by weight diluted ammonia water diluted with ion exchange water and heated at 120 ° C by a heat exchanger at a rate of 0.1 liter per minute. The polyester resin melt was transferred to the Cavitron (Eurotech Co., Ltd.). In this state, the Cavitron was operated under the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² , and the amorphous amorphous resin containing a particulate amorphous polyester resin (2) having a volume average particle diameter of 0.22 μm. A polyester resin dispersion (resin particle concentration: 20% by weight) was obtained.

-Preparation of crystalline polyester resin dispersion-
In a heat-dried three-necked flask, an acid component of dimethyl-5-sulfonate sodium 2 mol% and dimethyl sebacate 98 mol%, 1,6-hexanediol 100 mol%, and (n-Bu) ₂ SnO (acid) as a catalyst 0.06% by weight with respect to the components), and then the pressure in the container is reduced by depressurization, and the atmosphere is made inert with nitrogen gas and heated at 180 ° C. with mechanical stirring for 7 hours. Reflux was performed.
When the amount of distillate decreases, the pressure in the system is gradually reduced, and the temperature is gradually raised to 220 ° C. by vacuum distillation, followed by condensation polymerization for about 6 hours while stirring. When the contents of the flask became viscous, the molecular weight was confirmed by GPC, and when the weight average molecular weight reached 18000, vacuum distillation was stopped to obtain a polyester.
In addition, when this polyester resin was measured by DSC, it was found that it had a melting point of 68 degrees and was crystalline.

Subsequently, this was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with 0.37% by weight diluted ammonia water diluted with ion exchange water and heated at 120 ° C by a heat exchanger at a rate of 0.1 liter per minute. The polyester resin melt was transferred to the Cavitron (Eurotech Co., Ltd.).
In this state, the Cavitron was operated under the conditions of the rotor rotation speed of 60 Hz and the pressure of 5 kg / cm ² , and a crystalline polyester resin dispersion liquid containing particulate crystalline polyester resin having a volume average particle size of 0.26 μm ( Resin particle concentration: 20% by weight) was obtained.

-Preparation of styrene / acrylic resin dispersion-
-Styrene: 370 parts-n-butyl acrylate: 30 parts-Acrylic acid: 4 parts-Dodecanethiol: 24 parts-Carbon tetrabromide: 4 parts The above ingredients are mixed and dissolved to form a nonionic surfactant (Sanyo Kasei Co., Ltd .: Nonipol 400) 6 parts and anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 10 parts dissolved in ion exchange water 560 parts, dispersed in a flask And emulsified and mixed slowly for 10 minutes. At the time of this emulsification / mixing, 50 parts of ion-exchanged water having 4 parts of ammonium persulfate dissolved therein was added to the flask.
Subsequently, after the flask was purged with nitrogen, the contents were heated in an oil bath while stirring the flask until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours. Thus, a styrene-acrylic resin dispersion (resin particle concentration: 40% by weight) obtained by dispersing resin particles having a volume average particle size of 180 nm, a glass transition point of 59 ° C., and a weight average molecular weight (Mw) of 15,000. ) Was prepared. In addition, when this styrene acrylic resin was measured by DSC, melting | fusing point was not observed but it was amorphous.

-Preparation of ester compound dispersion (1)-
Add 1 mol of glycerin and 2.2 mol of palmitic acid to a four-flask equipped with a thermometer, nitrogen inlet tube, stirrer and condenser, add esterification reaction at normal pressure under nitrogen flow, and then glycerin dipalmi by molecular distillation. A tate (purity 90% by weight or more) was obtained.
After acetic anhydride equivalent to 1.1 mol was reacted with 1 mol of this glycerin dipalmitate, the acetic acid was removed by distillation under reduced pressure to obtain glycerin monoacetodipalmitate. 1000 parts of the obtained glycerin monoacetodipalmitate was put into a stainless steel container, and 50 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 5000 parts of ion-exchanged water were added to the homogenizer (IKA). Made by Ultra-Turrax T50), and then dispersed with a Manton Gorin high-pressure homogenizer (Gorin) to disperse a particulate ester compound having a volume average particle size of 250 nm. A compound dispersion (1) (ester compound concentration: 20% by weight) was prepared.

-Preparation of ester compound dispersion (2)-
While adding 1.1 mol of glycerin and 3.5 mol of stearic acid to a four-flask equipped with a thermometer, a nitrogen introduction tube, a stirrer and a cooling tube, the reaction water was distilled off at 220 ° C. under a nitrogen stream. The reaction was carried out at normal pressure for a time. When the esterification product thus obtained was analyzed by liquid chromatography, the proportion of glycerol tristearate was 79% by weight, and the remainder was glycerol monostearate and glycerol distearate.
Further, this esterification product was dispersed with a Manton Gorin high-pressure homogenizer (Gorin) together with an anionic surfactant and ion-exchanged water, as in the case of preparing the ester compound dispersion (1). An ester compound dispersion liquid (2) (ester compound concentration: 20% by weight) obtained by dispersing a particulate ester compound having an average particle diameter of 220 nm was prepared.

-Preparation of ester compound dispersion (3)-
In the same manner as in the preparation of the ester compound dispersion (2), an esterified product was prepared, and then 100 parts of toluene and 30 parts of ethanol were added to 500 parts of the esterified product. Part was added and stirred at 70 ° C. for 30 minutes. The mixture was allowed to stand for 30 minutes to remove the aqueous layer, and then 20 parts of ion-exchanged water was added to 100 parts of the esterification product used and stirred at 70 ° C. for 30 minutes. The aqueous layer was separated and removed. Washing with water was repeated until the pH of the aqueous layer to be removed became neutral. The remaining oil layer was distilled under reduced pressure at 180 ° C. under a nitrogen stream. The purified ester product thus obtained was analyzed by liquid chromatography. The content of glycerol tristearate was 90% by weight or more.
After 500 parts of this purified ester product was put into a 3 L poly beaker, 25 parts of an anionic surfactant and 2500 parts of ion-exchanged water were added and well blended with a homogenizer (IKA: Ultra Turrax T50). An ester compound dispersion (3) (ester compound concentration: 20% by weight) prepared by dispersing a particulate ester compound having a volume average particle size of 230 nm by dispersing with a Manton Gorin high-pressure homogenizer (Gorin) did.

-Preparation of ester compound dispersion (4)-
In the preparation of the ester compound dispersion (3), the raw material used for the dispersion was changed to a commercially available hardened castor oil (K3-WAX500: manufactured by Kawaken Fine Chemical Co., Ltd.), and was the same as the preparation of the ester compound dispersion (3). An ester compound dispersion (4) (ester compound concentration: 20% by weight) prepared by dispersing a particulate ester compound having a volume average particle diameter of 180 nm was dispersed under conditions.

-Preparation of ester compound dispersion (5)-
1 mol of glycerin and 1 mol of caprylic acid are added to a 4-rottle flask equipped with a thermometer, a nitrogen inlet tube, a stirrer, and a cooling tube, and after esterification at normal pressure under a nitrogen stream, glycerol monocaprylate (purity) 90% by weight or more). After acetic anhydride equivalent to 2.2 mol was reacted with 1 mol of this glycerin monocaprylate, acetic acid was removed by distillation under reduced pressure to obtain glycerin diacetomonocaprylate.
1000 parts of the obtained glycerin diacetomonocaprylate is put into a stainless steel container, 50 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 5000 parts of ion-exchanged water are added, and a homogenizer (IKA) Manufactured by Ultra-Turrax T50) and then dispersed with a Manton Gorin high-pressure homogenizer (Gorin) to disperse a particulate ester compound having a volume average particle size of 250 nm. Dispersion liquid (5) (ester compound concentration: 20% by weight) was prepared.

-Preparation of ester compound dispersion (6)-
1 mol of glycerin and 2.3 mol of behenic acid are added to a 4-rottle flask equipped with a thermometer, nitrogen introduction tube, stirrer and cooling tube, and after esterification at normal pressure under a nitrogen stream, glycerin dibehenate is obtained by molecular distillation. (Purity 90% by weight or more) was obtained.
After acetic anhydride equivalent to 1.1 mol was reacted with 1 mol of this glycerin dibehenate, the acetic acid was removed by distillation under reduced pressure to obtain glycerin monoacetodibehenate. 1000 parts of the obtained glycerin monoacetodibehenate is put into a stainless steel container, 50 parts of an anionic surfactant (Taika Power BN2060) and 5000 parts of ion-exchanged water are added, and a homogenizer (manufactured by IKA: Ultra Turrax T50). ), And then dispersed with a Manton Gorin high-pressure homogenizer (Gorin) to disperse an ester compound having a volume average particle size of 250 nm (ester compound) (ester compound) Concentration: 20% by weight) was prepared.

-Preparation of ester compound dispersion (7)-
To four flasks equipped with a thermometer, a nitrogen inlet tube, a stirrer and a condenser tube, 1.1 mol of glycerin and 2.3 mol of caprylic acid are added, and after esterification under a nitrogen stream at normal pressure, glycerin diester is obtained by molecular distillation. Caprylate (purity 90% by weight or more) was obtained. After acetic anhydride equivalent to 1.2 mol was reacted with 1 mol of this glycerin monocaprylate, acetic acid was removed by distillation under reduced pressure to obtain glycerin monoacetodicaprylate.
1000 parts of the obtained glycerin diacetodicaprylate is put in a stainless steel container, 50 parts of an anionic surfactant (Taika Power BN2060) and 5000 parts of ion-exchanged water are added, and a homogenizer (manufactured by IKA: Ultra Turrax T50). ), And then dispersed with a Manton Gorin high-pressure homogenizer (Gorin) to disperse an ester compound having a volume average particle size of 250 nm (ester compound) (ester compound) Concentration: 20% by weight) was prepared.

-Preparation of ester compound dispersion (8)-
To four flasks equipped with a thermometer, a nitrogen inlet tube, a stirrer, and a condenser tube, 1.1 mol of glycerin and 2.3 mol of mellic acid are added, and after esterification at normal pressure under a nitrogen stream, glycerin is obtained by molecular distillation. Dimericinate (purity 84% by weight or more) was obtained. After acetic anhydride equivalent to 1.2 mol was reacted with 1 mol of this glycerin dimericate, the acetic acid was removed by distillation under reduced pressure to obtain glycerin monoacetomelinate.
1000 parts of the resulting glycerin monoacetodimericate is put into a stainless steel container, 50 parts of an anionic surfactant (Taika Power BN2060) and 5000 parts of ion-exchanged water are added, and a homogenizer (manufactured by IKA: Ultra Turrax T50). ), And then dispersed with a Manton Gorin high-pressure homogenizer (Gorin) to disperse an ester compound having a volume average particle size of 250 nm (ester compound) (ester compound) Concentration: 20% by weight) was prepared.

-Preparation of release agent dispersion (1)-
-Ester wax WEP5 (manufactured by NOF Corporation): 500 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 50 parts-Ion-exchanged water: 2000 parts After heating and dispersing using a homogenizer (manufactured by IKA: Ultra Turrax T50), the dispersion is treated with a Manton Gorin high-pressure homogenizer (Gorin) to disperse the release agent having a volume average particle diameter of 210 nm. A release agent dispersion (1) (release agent concentration: 20% by weight) was prepared.

-Preparation of release agent dispersion (2)-
Carnauba wax (Nippon Yushi Co., Ltd.): 500 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 50 parts Ion-exchanged water: 2000 parts Heat the above ingredients to 120 ° C Then, after being dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), the dispersion is treated with a Manton Gorin high-pressure homogenizer (Gorin) to disperse the release agent having a volume average particle size of 240 nm. A release agent dispersion (2) (concentration of release agent: 20% by weight) was prepared.

-Preparation of release agent dispersion (3)-
・ Ester wax WEP6 (Nippon Yushi Co., Ltd.): 500 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 50 parts ・ Ion-exchanged water: 2000 parts After heating and dispersing using a homogenizer (manufactured by IKA: Ultra Tarrax T50), the dispersion is treated with a Manton Gorin high-pressure homogenizer (Gorin) to disperse the release agent having a volume average particle size of 225 nm. A release agent dispersion (3) (release agent concentration: 20% by weight) was prepared.

-Preparation of colorant dispersion-
-Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 100 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 15 parts-Ion-exchanged water: 900 Part A colorant obtained by mixing and dissolving the above components and dispersing the colorant (cyan pigment) by dispersing for about 1 hour using a high-pressure impact disperser ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). A dispersion was prepared. The volume average particle size of the colorant (cyan pigment) in the colorant dispersion was 0.15 μm, and the colorant particle concentration was 23% by weight.

<< Example A , Reference Example A and Comparative Example A >>
( Reference Example A1)
-Production of toner base particles A (1)-
Amorphous polyester resin dispersion (1): 657 parts Colorant dispersion: 27.2 parts Anionic surfactant (dowfax2A1 20% aqueous solution): 12.9 parts Ester compound dispersion (1): 66.3 parts / ion exchange water: 500 parts Among the above raw materials, ion exchange water, amorphous polyester resin dispersion (1) and anionic surface activity are added to a polymerization kettle equipped with a pH meter, a stirring blade and a thermometer. The surfactant was put into the amorphous polyester resin dispersion while stirring at 200 rpm for 15 minutes.
Subsequently, the colorant dispersion and the ester compound dispersion (1) were added thereto and mixed, and then a 0.3 M nitric acid aqueous solution was added to the raw material mixture to adjust the pH to 3.5. Then, 30 parts of an aqueous nitric acid solution containing 10% by weight of polyaluminum chloride as a flocculant was dropped while applying a shear force at 1000 rpm with Ultraturrax.
In addition, since the viscosity of the raw material mixture suddenly increased during the dropping of the flocculant, the dropping speed was reduced when the viscosity increased so that the flocculant was not biased to one place. When the dropping of the flocculant was completed, the rotational speed was further increased to 6000 rpm and the mixture was stirred for 5 minutes to sufficiently mix the flocculant and the raw material mixture.

  Subsequently, the raw material mixture was stirred at 550 to 650 rpm while being heated to 30 ° C. with a mantle heater. After stirring for 30 to 60 minutes, it was confirmed that the primary particle diameter was stably formed using a Coulter counter [TA-II] type (aperture diameter: 50 μm; manufactured by Coulter, Inc.), and then 0 for growing aggregated particles. The temperature was raised to 48 to 52 ° C. at 5 ° C./min. In order to stop the growth of the aggregated particles when the aggregated particles become 5.7 μm while appropriately checking the size of the aggregated particles using a Coulter counter, a raw material mixture is added. The pH of was controlled at 9.0.

Subsequently, when the pH starts to drop naturally after adjusting the pH to 9.0, in order to prevent the formed aggregated particles from being dispersed, the rotational speed is decreased to 200 rpm or less, and then the aggregated particles are fused. The temperature was raised to 85 ° C. at 1 ° C./min.
At the time of this temperature increase, an appropriate amount of 1M sodium hydroxide aqueous solution is added as necessary in order to prevent the aggregated particles whose particle size growth has stopped due to a decrease in pH of the raw material mixture as the temperature increases. added.
After 30 minutes at 85 ° C., the aggregated particles gradually merged, and after about 1 hour, the aggregated particles became spherical and fused. After confirming this fusion state with a microscope, heating was stopped and the temperature was lowered to room temperature at 1 ° C./min.

  The fused particles thus obtained are sieved with a mesh having an opening of 45 μm, washed with water, filtered once to separate into solid and liquid, and ion-exchanged water is added to the particles on the filter paper. A slurry corresponding to 20% C (toner particle solid content concentration) was prepared. While stirring this slurry, 1M nitric acid was added to maintain the pH at 3.0, acid washing was performed for 30 minutes, and filtration was performed again. The particles on the filter paper were reslurried and repeatedly washed with water, and then dried with a vacuum dryer. The toner mother particles A (1) granulated as described above had a volume average particle size of 5.6 μm.

( Reference Example A2)
-Production of toner base particles A (2)-
Amorphous polyester resin dispersion (1): 551 parts Colorant dispersion: 27.2 parts Anionic surfactant (dowfax2A1 20% aqueous solution): 10.9 parts Ester compound dispersion (2): 66.3 parts, ion-exchanged water: 411 parts Agglomerated particles were grown by granulating under the same conditions as in Reference Example A1, except that the above was used as a raw material. When the aggregated particle diameter reached 5.4 μm, in order to form a coating layer on the aggregated particle surface, 2.6 parts of an anionic surfactant (dowfax2A1 20% aqueous solution) was added in advance, and then adjusted to pH 4. 105 parts of an amorphous polyester resin dispersion liquid (1) adjusted to 0 was added dropwise.
After completion of dropping, the mixture is held for 5 minutes, and after confirming the adhesion of the resin particles to the surface of the aggregated particles with a Coulter counter, 1M is used in the same manner as in Reference Example A1 to stop the growth of the aggregated particles on which the coating layer is formed. An appropriate amount of an aqueous sodium hydroxide solution was added.
Thereafter, to fuse the coated aggregated particles, the temperature is raised to 85 ° C at 1 ° C / min, maintained at 85 ° C for 1 hour, and further maintained at 95 ° C for 2 hours to further integrate the coated aggregated particles. And fused. Thereafter, sieving, washing and drying were carried out under the same conditions as in Reference Example A1 , to obtain toner mother particles A (2) having a volume average particle size of 5.7 μm.

( Reference Example A3)
-Production of toner base particles A (3)-
In Reference Example A2, agglomerated particles were grown by granulating under the same conditions as in Reference Example A2, except that instead of the ester compound dispersion (2) as the raw material, the ester compound dispersion (3) was used. . When the aggregated particle diameter reached 5.7 μm, the amorphous polyester resin dispersion liquid (1) was dropped to form a coating layer under the same conditions as in Reference Example A2, and the aggregated particles were coated.
Thereafter, the growth of aggregated particles is stopped and fused under the same conditions as in Reference Example A2, and toner mother particles A (3) having a volume average particle diameter of 6.0 μm are obtained through sieving, washing, and drying processes. It was.

( Reference Example A4)
-Production of toner base particles A (4)-
Amorphous polyester resin dispersion (1): 517 parts Colorant dispersion: 27.2 parts Anionic surfactant (dowfax2A1 20% aqueous solution): 10.5 parts Ester compound dispersion (3): 66.3 parts Release agent dispersion (1): 69.0 parts Ion exchange water: 430 parts
In Reference Example A3, except that the above composition was used as a raw material, granulation was performed under the same conditions as in Reference Example A3 to grow aggregated particles. When the aggregated particle diameter reached 5.8 μm, the amorphous polyester resin dispersion (1) was dropped to form a coating layer under the same conditions as in Reference Example A3, and the aggregated particles were coated.
Thereafter, the growth of the aggregated particles is stopped and fused under the same conditions as in Reference Example A3, and the toner base particles A (4) having a volume average particle size of 6.3 μm are obtained through the steps of sieving, washing and drying. It was.

(Example A 1 )
-Production of toner base particles A (5)-
In Reference Example A4, instead of the ester compound dispersion (3), the ester compound dispersion (4) was used as the raw material, and the release agent dispersion (2) was used instead of the release agent dispersion (1). Except for the above, granulation was performed under the same conditions as in Reference Example A4 to grow aggregated particles.
When the aggregated particle diameter reached 5.6 μm, the amorphous polyester resin dispersion liquid (1) was dropped to form a coating layer under the same conditions as in Reference Example A4, and the aggregated particles were coated.
Thereafter, the growth of the aggregated particles is stopped and fused under the same conditions as in Reference Example A4, and toner mother particles A (5) having a volume average particle diameter of 5.9 μm are obtained through the steps of sieving, washing, and drying. It was.

(Reference Example A 5)
-Production of toner base particles A (6)-
In Reference Example A4, except that the ester compound dispersion (3) was changed to 15.6 parts, granulation was performed under the same conditions as in Reference Example A4 to grow aggregated particles.
When the aggregated particle diameter reached 5.4 μm, the amorphous polyester resin dispersion (1) was dropped to form a coating layer under the same conditions as in Reference Example A4, and the aggregated particles were coated.
Thereafter, the growth of the coated agglomerated particles is stopped under the same conditions as in Reference Example A4, fused, passed through sieving, washing, and drying steps, and toner base particles A (6) having a volume average particle diameter of 5.8 μm are obtained. Obtained.

( Reference Example A 6 )
-Production of toner base particles A (7)-
In Reference Example A4, except that the ester compound dispersion (3) was changed to 121.3 parts, granulation was performed under the same conditions as in Reference Example A4 to grow aggregated particles.
When the aggregated particle diameter reached 5.6 μm, the amorphous polyester resin dispersion liquid (1) was dropped to form a coating layer under the same conditions as in Reference Example A4, and the aggregated particles were coated.
Thereafter, the growth of the coated agglomerated particles is stopped under the same conditions as in Reference Example A4, fused, passed through sieving, washing, and drying steps, and toner base particles A (7) having a volume average particle size of 6.4 μm are obtained. Obtained.

(Comparative Example A1)
-Production of toner base particles A (8)-
In Reference Example A1, 330 parts of a styrene / acrylic resin dispersion was used as a raw material instead of the amorphous polyester resin dispersion (1), and the pH before dropping the polyaluminum chloride nitric acid aqueous solution as a flocculant was 2.5. A raw material mixture was prepared under the same conditions as in Reference Example A1, except that the amount was adjusted to.
Next, in the temperature raising step for agglomeration growth, the agglomeration temperature is raised to 52 ° C., and when the agglomerated particle diameter becomes 5.5 μm, a 1M sodium hydroxide aqueous solution is added to adjust the pH to 6.5. Agglomerated growth was stopped.
Then, the temperature was raised to 95 ° C. and fused. Thereafter, toner mother particles A (8) having a volume average particle diameter of 5.8 μm were obtained through sieving, washing and drying.

(Comparative Example A2)
-Production of toner base particles A (9)-
In Reference Example A3, aggregation and fusion were performed under the same conditions as in Reference Example A3, except that the ester compound dispersion liquid (3) was removed from the raw material. Thereafter, sieving, washing and drying were carried out under the same conditions as in Reference Example A3 to obtain toner base particles A (9) having a volume average particle size of 5.9 μm.

(Comparative Example A3)
-Production of toner base particles A (10)-
In Reference Example A2, aggregation and fusion were performed under the same conditions as in Reference Example A2, except that instead of the ester compound dispersion (2) as the raw material, the ester compound dispersion (5) was used. Thereafter, sieving, washing and drying were carried out under the same conditions as in Reference Example A2, to obtain toner mother particles A (10) having a volume average particle diameter of 6.1 μm.

(Comparative Example A4)
-Production of toner base particles A (11)-
In Example A 1, except that the reduced ester compound dispersion (4) in 11.8 parts performs granulation under the same conditions as in Example A 1, were grown aggregated particles.
When the agglomerated particle size becomes 5.5 [mu] m, it was added dropwise a amorphous polyester resin dispersion (1) in order to form a coating layer under the same conditions as in Example A 1, was coated aggregated particles.
Later, under the same conditions as in Example A 1, stop the growth of the coating aggregated particles, it proceeded fusion. And held for 2 hours at 95 ° C. However, as compared with Example A 1, it does not proceed fusion of the toner surface was finally fused and held an additional hour. Thereafter, sieving under the same conditions as in Example A 1, washing, and drying steps to obtain toner mother particles A (11) having a volume average particle size of 5.9 [mu] m.

(Comparative Example A5)
-Production of toner base particles A (12)-
In Example A 1, except that the ester compound dispersion (4) to 130.6 parts, performs granulation under the same conditions as in Example A 1, were grown aggregated particles.
Agglomerated particle size upon reaching the 5.6 [mu] m, was added dropwise a amorphous polyester resin dispersion (1) in order to form a coating layer under the same conditions as in Example A 1, was coated aggregated particles.
Later, under the same conditions as in Example A 1, has been stopped the growth of the coating aggregated particles during the temperature rise for the next fusion was gradually particle growth. Thereafter, the fusion itself almost spheronized Retention of 85 ° C. 1 hour, sieving under the same conditions as in Example A 1, washing, and drying processes, the toner mother particles A having a volume average particle size of 6.5μm (12) was obtained.

(Comparative Example A6)
-Production of toner base particles A (13)-
In Example A 1, except for using an ester compound dispersion (8) in place of the ester compound dispersion (4) performs a granulation under the same conditions as in Example A 1, were grown aggregated particles .
When the agglomerated particle size becomes 5.5 [mu] m, it was added dropwise a amorphous polyester resin dispersion (1) in order to form a coating layer under the same conditions as in Example A 1, was coated aggregated particles.
Later, under the same conditions as in Example A 1, stop the growth of the coating aggregated particles, fused, sieving, washing and drying processes, the toner mother particles A having a volume average particle size of 5.9 [mu] m (13) Got. After drying, the toner was observed with a scanning electron microscope (SEM: S-4100, manufactured by Hitachi, Ltd.), and precipitates that were not included in the toner surface were observed.

<Evaluation of toner fixing property, document storage property, charging property, storage stability>
(Evaluation of fixability and document preservation)
To each of the toner base particles A (1) to A (13), 1.2 parts by weight and 0.4 parts by weight of titania fine powder and silica fine powder as external additives are added with respect to 100 parts by weight of the toner base particles, By mixing with a Henschel mixer, toners A (1) to A (13) for developing electrostatic images were obtained.
Next, 5 parts by weight of the toner to which the external additive was added and 100 parts by weight of resin-coated ferrite particles (volume average particle size 35 μm) were mixed to prepare a two-component developer. An image was printed out using a copying machine (Document center color a450 manufactured by Fuji Xerox Co., Ltd.) to obtain an unfixed image.

  Next, using a belt nip type external fixing machine, the fixing temperature of the image and the hot offset property were evaluated while gradually increasing the fixing temperature between 90 ° C. and 220 ° C. The low-temperature fixability is determined by fixing an unfixed solid image (25 mm × 25 mm), bending it with a weight under a certain load, grading the degree of image defect in that portion, and fixing temperature at which it exceeds a certain grade. Was used as an index of low-temperature fixability.

On the other hand, regarding the evaluation of document storage stability, after fixing two unfixed images created at the time of the fixing evaluation at 150 ° C. with an external fixing device, the image portion overlaps with the non-image portion and the image portion. Thus, the weight was placed so as to be equivalent to 80 g / cm ^{2 with} respect to the overlapped portion, and left in a constant temperature and humidity chamber at 60 ° C. and 50% humidity for 7 days. After being left, the degree of image loss of the two fixed images superimposed was graded in five stages from “G1” to “G5” shown below. The standards for each grade are as follows.

G1: Since the image portions are adhered to each other, the paper on which the image is fixed is peeled off, the image is severely lost, and the image is clearly transferred to the non-image portion.
G2: Since the images are bonded to each other, white spots of image defects are generated in some parts of the image portion.
G3: When separating the two superimposed images, image blurring or gloss reduction occurs on the fixing surfaces of each other, but the image has an acceptable level with almost no image loss. There is a slight transition in the non-image area.
G4: When the two overlapped images are separated, a crisp sound is heard, and a slight image transition is seen in the non-image part, but there is no image loss, and there is no problem. Level G5: Both the image part and the non-image There is no image loss or image transfer.

(Evaluation of chargeability)
1.5 parts by weight of each of the electrostatic image developing toners A (1) to A (13) and 30 parts by weight of resin-coated ferrite particles (volume average particle size 35 μm) prepared at the time of evaluation of the fixability are covered. Weigh in a glass bottle with a glass bottle and season for 24 hours under high temperature and high humidity (temperature 28 ° C, humidity 85%) and low temperature and low humidity (temperature 10 ° C, humidity 15%), then shake with a tumbler mixer for 5 minutes did. The charge amount (μc) of the toner in both environments was measured with a blow-off charge amount measuring device.

(Evaluation of storage stability)
2 g of each toner A (1) to A (13) for electrostatic image development is weighed and left in a chamber at 50 ° C. and 50% humidity for 17 hours, then placed on a 32 μm mesh sieve and vibrated for 30 seconds. The amount remaining above was weighed, and the degree of aggregation of the toner was calculated from the following formula (1) to evaluate the storage stability.
Formula (1) Aggregation degree (%) = (toner remaining on sieve (g) / 2 (g)) × 100

  Table 1 shows the characteristics of the toner produced as described above. Table 2 shows the toner fixing characteristics, document storage characteristics, charging characteristics, and toner storage stability shown in Table 1.

From the results shown in Tables 1 and 2, Example A1 and Reference Examples A1 to A6 use toner containing an amorphous polyester resin and an ester compound, so that low-temperature fixability, chargeability, document storage stability and Good toner storage stability was obtained. In addition, the hot offset property was excellent.
On the other hand, in Comparative Example A1, does not use a non-crystalline polyester resin in the binder resin, either because even an ester compound is not obtained plasticizing effect, the minimum fixing temperature as compared to the Examples and Reference Examples It was high. In addition, document storage and toner storage deteriorated.
Further, in Comparative Example A2 in which no ester compound was used, although the chargeability and other characteristics were good, no improvement in low-temperature fixability was observed.
Further, in Comparative Example A3 in which the carbon number of any acyl group constituting the used ester compound is less than 10, although the plasticizing effect of the toner is sufficient, the result of impairing the toner storage stability due to excessive plasticization It became.

Further, in Comparative Example A6 in which the ester compound used contains an acyl group having more than 28 carbon atoms (30 carbon atoms) in addition to an acyl group having less than 10 carbon atoms, the inclusion in the toner is poor, and it is precipitated in the fusing step. As a result, the degree of aggregation of the toner is deteriorated.
Further, in Comparative Example A4 where the amount of the ester compound is less than 2 parts by weight, the plasticization of the toner is poor, so that the fusion process takes time and the effect on the low-temperature fixability is insufficient. On the other hand, in Comparative Example A5 in which the ester compound was added in an amount of more than 20 parts by weight, not only the particle growth was difficult to control, but the excessive plasticization effect caused the decrease in the glass transition point of the toner. Deterioration in storage stability was remarkable.

<< Example B , Reference Example B and Comparative Example B >>
( Reference Example B1)
-Production of toner base particles B (1)-
Amorphous polyester resin dispersion (1): 657 parts Colorant dispersion: 25.5 parts Anionic surfactant (dowfax 2A1 20% aqueous solution): 12.9 parts Ester compound dispersion (6): 66.3 parts, ion-exchanged water: 500 parts Among the above raw materials, put ion-exchanged water, amorphous polyester resin dispersion and anionic surfactant into a polymerization kettle equipped with a pH meter, stirring blades, and thermometer. The surfactant was blended with the amorphous polyester resin dispersion while stirring at 200 rpm for 15 minutes. Subsequently, the colorant dispersion and the ester compound dispersion (6) were added to and mixed with this, and then a 0.3 M nitric acid aqueous solution was added to the raw material mixture to adjust the pH to 3.5. Subsequently, 30 parts of a 10% nitric acid aqueous solution of polyaluminum chloride as a flocculant was dropped while applying a shear force at 1000 rpm with Ultraturrax.
During the dropping of the flocculant, the viscosity of the raw material mixture rapidly increased. Therefore, when the viscosity increased, the dropping speed was reduced so that the flocculant was not biased to one place. When the dropping of the flocculant was completed, the rotational speed was further increased to 6000 rpm and the mixture was stirred for 5 minutes to sufficiently mix the flocculant and the raw material mixture.

Next, the raw material mixture is stirred at 550 to 650 rpm while heating to 30 ° C. with a mantle heater. After stirring for 30 to 60 minutes, it was confirmed that the primary particle diameter was stably formed using a Coulter counter [TA-II] type (aperture diameter: 50 μm; manufactured by Coulter, Inc.). The temperature was raised to 48 to 52 ° C. at 5 ° C./min.
While confirming the size of the aggregated particles as appropriate using a Coulter counter, when the aggregated particles reach 5.5 μm, an anionic surfactant (dowfax2A1 20% aqueous solution is used in advance to form a coating layer on the aggregated particle surface. 3.1 parts of Dow Chemical Co., Ltd.) and 105 parts of an amorphous polyester resin dispersion (1) having a pH adjusted to 4.0 were added dropwise.
Next, after holding for 5 minutes and confirming adhesion to the aggregated particles with a Coulter counter, an appropriate amount of 1M sodium hydroxide aqueous solution was added to stop the growth of the aggregated particles forming the coating layer, and the pH of the raw material mixture was adjusted. Control to 9.0.

Subsequently, when the pH starts to decrease naturally after adjusting the pH to 9.0, in order to prevent the aggregated particles once formed from falling, the rotational speed is decreased to 200 rpm or less, and then the aggregated particles are fused. The temperature was raised to 85 ° C. at 1 ° C./min. At the time of this temperature increase, the pH of the raw material mixture decreases with the temperature increase, and there is a possibility that the aggregated particles that stopped the particle size growth may grow again in the particle size. Therefore, if necessary, an appropriate amount of 1M sodium hydroxide aqueous solution is used. Added.
After 30 minutes at 85 ° C., the aggregated particles gradually merged, and after about 1 hour, the aggregated particles became spherical and fused. After confirming this fusion with a microscope, the heating was stopped and the temperature was lowered to room temperature at 1 ° C./min.

  The fused particles thus obtained are sieved with a mesh having an opening of 45 μm, washed with water, filtered once to separate into solid and liquid, and ion-exchanged water is added to the particles on the filter paper. A slurry corresponding to 20% C (toner particle solid content concentration) was prepared. While stirring this slurry, 1M nitric acid was added to maintain the pH at 3.0, acid washing was performed for 30 minutes, and filtration was performed again. The particles on the filter paper were reslurried and repeatedly washed with water, and then dried with a vacuum dryer. The volume average particle size of the toner base particles B (1) granulated as described above was 5.9 μm.

( Reference Example B2)
-Production of toner base particles B (2)-
In Reference Example B1, granulation was performed under the same conditions as in Reference Example B1 except that the ester compound dispersion (3) was used instead of the ester compound dispersion (6) to grow aggregated particles.
Next, when the aggregated particle diameter becomes 5.4 μm, 3.1 parts of an anionic surfactant (dowfax2A1 20% aqueous solution, manufactured by Dow Chemical Co.) is added in advance in order to form a coating layer on the aggregated particle surface. After acclimatization, 105 parts of an amorphous polyester resin dispersion (1) adjusted to pH 4.0 was added dropwise.
After completion of dropping, the mixture is held for 5 minutes, and after confirming adhesion to the aggregated particles with a Coulter counter, in order to stop the growth of the aggregated particles forming the coating layer, a 1M sodium hydroxide aqueous solution is used as in Reference Example B1. An appropriate amount was added.
Thereafter, they were fused under the same conditions as in Reference Example B1, sieved, washed and dried to obtain toner base particles B (2) having a volume average particle size of 5.8 μm.

(Example B 1 )
-Production of toner base particles B (3)-
In Reference Example B1, the same procedure as in Reference Example B1, except that instead of the ester compound dispersion (6), the ester compound dispersion (4) was used and the amount of the anionic surfactant was 14.2 parts. Granulation was performed under conditions to grow aggregated particles.
When the aggregated particle diameter reached 5.7 μm, the amorphous polyester resin dispersion (1) was dropped to form a coating layer under the same conditions as in Reference Example B1, and the aggregated particles were coated. Thereafter, the growth of the aggregated particles is stopped and fused under the same conditions as in Reference Example B1, and the toner base particles B (3) having a volume average particle size of 6.3 μm are obtained through the steps of sieving, washing and drying. It was.

(Example B 2 )
-Production of toner base particles B (4)-
Amorphous polyester resin dispersion (2): 517 parts Colorant dispersion: 25.5 parts Anionic surfactant (dowfax2A1 20% aqueous solution): 13.8 parts Ester compound dispersion (4): 66.3 parts release agent dispersion (3): 69.0 parts ion exchanged water: in 430 parts of example B 1, as except for using the raw material, under the same conditions as in reference example B1, granulated Granulation was performed to grow agglomerated particles. When the agglomerated particle diameter reached 5.6 μm, in order to form a coating layer on the agglomerated particle surface, 2.9 parts of an anionic surfactant (dowfax2A1 20% aqueous solution, manufactured by Dow Chemical Co., Ltd.) was added in advance and blended. 124 parts of an amorphous polyester resin dispersion liquid (2) adjusted to pH 4.0 was dropped to cover the aggregated particles.
Thereafter, the growth of the aggregated particles is stopped and fused under the same conditions as in Reference Example B1, and the toner base particles B (4) having a volume average particle diameter of 6.1 μm are obtained through the steps of sieving, washing and drying. It was.

(Example B 3 )
-Production of toner base particles B (5)-
Non In Example B 2, instead of the release agent dispersion liquid as a raw material (3), the release agent dispersion liquid (2), in place of the amorphous polyester resin dispersion (2) covering the surface of the aggregated particles Granulation was performed under the same conditions as in Example B 2 except that the crystalline polyester resin dispersion (1) was used, and the aggregated particles were coated.
Subsequently, in order to stop the growth of the aggregated particles, a 1M sodium hydroxide aqueous solution was added to control the pH to 9.5. Later, under the same conditions as in Example B 2, fused, sieving, washing and drying steps to obtain toner mother particles B (5) of the volume average particle diameter 6.2 .mu.m.

(Comparative Example B1)
-Production of toner base particles B (6)-
In Reference Example B1, 330 parts of styrene / acrylic resin dispersion was used as a raw material instead of the amorphous polyester resin dispersion (1), and the pH before dropping the polyaluminum chloride nitric acid aqueous solution as a coagulant was 2.5. The raw material mixture was prepared under the same conditions as in Reference Example B1, except that the control was performed.
Next, in the temperature raising step for agglomeration growth, the agglomeration temperature is raised to 52 ° C., and when the agglomerated particle diameter becomes 5.5 μm, a 1M sodium hydroxide aqueous solution is added to adjust the pH to 6.5. Agglomerated growth was stopped. Then, the temperature was raised to 95 ° C. and fused. Thereafter, toner mother particles B (6) having a volume average particle size of 5.7 μm were obtained through sieving, washing and drying.

(Comparative Example B2)
-Production of toner base particles B (7)-
In Example B 2, the raw material an ester compound dispersion liquid except for (4), except that the pH was controlled in the aggregation step to 2.7, under the same conditions as in Example B 2, aggregation, fusion was performed. Thereafter Example B 2 and the same conditions, sieving, washing and dried to obtain toner mother particles B (7) having a volume average particle size of 5.4 [mu] m.

(Comparative Example B3)
-Production of toner base particles B (8)-
In Example B 2, as a raw material, instead of the amorphous polyester resin dispersion (2), except that using the crystalline polyester resin dispersion, the pH was controlled in the aggregation step to 2.7 Example B Under the same conditions as in No. 1 , cohesive growth was performed.
Subsequently, the stop of cohesive growth was performed by setting the pH to 9.5. In the subsequent fusing step, the temperature was raised to 75 ° C. at a rate of temperature rise of 1 ° C./min, and fusing proceeded at that temperature. Thereafter the same conditions as in Example B 1, sieving, washing and dried to obtain toner mother particles B (8) having a volume average particle size of 5.5 [mu] m.

(Comparative Example B4)
-Production of toner base particles B (9)-
In Example B 2, instead of the raw material as an ester compound dispersion (4), except for using an ester compound dispersion liquid (7), under the same conditions as in Reference Example B2, aggregation, fusion was performed. Then, under the same conditions as in Example B 1, sieving, washing and dried to obtain toner mother particles B (9) having a volume average particle diameter of 6.0 .mu.m.

<Various toner evaluation>
-Evaluation of fixability and document preservation-
To the toner base particles B (1) to B (9), 1.0 part by weight of titania fine powder and 0.6 part by weight of silica fine powder are added as an external additive to 100 parts by weight of the toner base particles, By mixing with a Henschel mixer, toners B (1) to B (9) for developing electrostatic images were obtained.
Subsequently, 8 parts by weight of each of the electrostatic charge developing toners B (1) to B (9) and 100 parts by weight of a resin-coated ferrite carrier (volume average particle size 35 μm) are mixed to prepare a two-component developer, This was imaged using a commercially available electrophotographic copying machine (Document color a450 manufactured by Fuji Xerox Co., Ltd.) to obtain an unfixed image.
Next, the fixability and document storage stability were evaluated using a belt nip type external fixing device in the same manner as in the evaluation of Example A / Reference Example A / Comparative Example A.

-Evaluation of volume resistivity-
6 g of each of the toner base particles B (1) to B (9) was weighed and spread on a compression molding machine having a diameter of 5 cm, and a load of 10 tf was applied for 1 minute to produce a disk-shaped toner molding having a thickness of about 3 mm. . Each disk-shaped molded product was measured for dielectric characteristics under the following conditions using an LCR meter 6440A.
・ Frequency: 1000Hz
・ Voltage: 5rms
Measurement repeat number: 100
・ External bias: OFF
Tan δ calculated by this measurement was defined as the loss tangent of each toner.

-Evaluation of chargeability and charge decay due to neglect-
1.5 parts by weight of each of the electrostatic charge image developing toners B (1) to B (9) prepared at the time of evaluating the fixability and 30 parts by weight of resin-coated ferrite particles (volume average particle size 35 μm) Weigh in a glass bottle with a glass bottle and season for 24 hours under high temperature and high humidity (temperature 28 ° C, humidity 85%) and low temperature and low humidity (temperature 10 ° C, humidity 15%), then shake with a tumbler mixer for 5 minutes did. The charge amount (μc) of the toner in both environments was measured with a blow-off charge amount measuring device.
In addition, the charge maintenance property when left standing was evaluated by a charge decay rate calculated from the charge amount measured under the following conditions.
Let A be the charge amount of the developer after seasoning for 12 hours in an environment of temperature 22 ° C. and humidity 50% and then stirring and shaking for 2 minutes with a Turbula mixer. Next, assuming that the charge amount after the developer is allowed to stand for 24 hours in the above environment is B, the charge decay rate can be obtained from the following equation (2).
Formula (2) Charge decay rate = B / A x 100 (%)

-Evaluation of storage stability-
The storage stability was evaluated in the same manner as in Example A / Reference Example A / Comparative Example A.

-Evaluation of transferability-
An image forming apparatus having a configuration shown in FIG. 1 (manufactured by Fuji Xerox Co., Ltd.) is used for each of the two-component developers of the electrostatic charge image developing toners B (1) to B (9) prepared at the time of evaluating the fixability. , Doccentre color a450) was put in a developing machine of an off-line evaluator, and the transfer remaining amount was evaluated as follows.

The primary transfer bias is changed from 15 μA to 30 μA in 3 μA increments, and a 2.5 cm × 4 cm rectangular toner image (image density) with an image coverage density of 100% according to the bias with the lowest transfer remaining amount for each toner. 1 mg / cm ² ), and when the toner image is primarily transferred to the intermediate transfer belt, the apparatus is stopped, and the toner remaining on the photosensitive drum is transferred to the tape, which is repeated 10 times. The total toner weight was evaluated according to the following criteria.
A: Less than 0.5 mg B: 0.5 mg or more and less than 1.5 mg Δ: 1.5 mg or more and less than 3.5 mg x: 3.5 mg or more

The intermediate transfer belt used at this time had a surface resistivity of 11.2 log Ω / cm ² and a volume resistivity of 9.2 log Ω · cm.

Next, the evaluation of white streaky toner scattering was performed as follows. That is, the static elimination brush (corresponding to the static elimination brush 6 in FIG. 1) is removed from the image forming apparatus, a toner image with an image coverage density of 30% is formed on the entire surface of the A3 size paper, and the occurrence of white streaks is visually observed. Evaluation was made according to the following criteria.
○: White streak does not occur Δ: White streak occurs but acceptable level ×: Level where white streak occurs and causes image quality problems

  Table 3 shows various characteristics of the toner produced as described above. Table 4 shows the toner fixing characteristics, document storage characteristics, charging characteristics, and transfer characteristics shown in Table 3.

From the results shown in Tables 3 and 4, Examples B1 to B3 and Reference Examples B1 to B2 are good without problems with respect to transferability and other secondary obstacles while achieving both good charge amount and low temperature fixability. The characteristics are shown. Further, in Examples B 2 and B 3 using an ester wax, further enlargement of the fixing latitude was confirmed.

  On the other hand, in Comparative Example B1 and Comparative Example B3 that do not use an amorphous polyester resin as a binder resin, and Comparative Example B2 that does not use an ester compound, it is difficult to achieve both low-temperature fixability, chargeability, and transferability. It was a result. Further, in Comparative Example B4 in which any acyl group constituting the ester compound has less than 10 carbon atoms (8 and 1 carbon atoms), there is no problem in low-temperature fixability, but there is a problem in storage stability of the toner. .

-Evaluation of the effect of intermediate transfer resistivity on transfer-
(Example B 2 a to Example B 2 d)
Regarding the influence of the resistivity of the intermediate transfer member on the transfer, an image forming apparatus (manufactured by Fuji Xerox Co., Ltd., Documente color a450) having the same configuration as the apparatus shown in FIG. 1 was used. In the evaluation, four types of intermediate transfer belts 2 having different resistance values were attached and evaluated.
The intermediate transfer belt 2 is a conductive endless belt, made of polyimide, and imparted with conductivity by containing an appropriate amount of carbon black. The belt size needs to be larger than the maximum print image size, and the belt circumference is preferably an integral multiple of the photoreceptor drum circumference from the viewpoint of preventing color misregistration of each color toner image. A drum having a circumference of 528 mm, a width of 330 mm, and a thickness of 90 μm, which is twice the circumference of the body drum, was used.

  As the intermediate transfer belt used for the evaluation, four types of belts having different surface resistivity (ρs) and volume resistivity (ρv) were prepared by changing the carbon black content. The belt resistance was measured by connecting an HR probe (Mitsubishi Yuka Co., Ltd.) to a high resistance / microammeter (R8340A manufactured by Advantest) and applying 100V to the probe.

In order to examine the resistance of the intermediate transfer belt and the effect of improving the white streaks by the neutralizing brush, the degree of white streaks in the four types of belts was evaluated.
Experiments using toner B (4) for developing electrostatic images used in Example B 2, the sheet the entire surface of the A3-size, to form an image coverage density of 30% of the toner image, visually white streaks toner scattering And evaluated according to the following criteria.
◯: Not generated Δ: Slightly generated but no problem level ×: Significantly generated and troublesome use In addition to white streaky toner scattering, the presence or absence of other image quality defects was evaluated simultaneously. Table 5 shows the resistance values of the four types of intermediate transfer belts and the evaluation results of the respective transfer properties.

From the results shown in Table 5, white streaky toner scattering did not occur when the surface resistivity of the intermediate transfer belt was 10 ¹³ Ω / cm ² or less and the volume resistivity was 10 ¹³ Ω · cm or less. In Example B 2 d, which was higher than the ratio, a slight scattering appeared, but it was at a level with no problem.
On the other hand, the surface resistivity of 10 ⁹ Ω / cm ² or less, although and volume resistivity in the belt 10 ⁷ Ω · cm or less in Examples B 2 c white streaks toner scattering was observed, the secondary transfer It was confirmed that the primary transfer efficiency slightly decreased at the moment when the bias was applied. This is considered to be because the secondary transfer current flows through the intermediate transfer belt and flows into the primary transfer portion because the belt resistivity is low, but there is no practical problem.
In addition, in Example B 2 c and Example B 2 b, the line image was slightly blurred. This is thought to occur because the surface resistivity is low and the transfer electric field spreads to the upstream side of the primary transfer part during the primary transfer, and the transfer is performed in the minute gap region and the toner is scattered. Even the level was acceptable.

1 is a schematic diagram of an intermediate transfer belt type color image forming apparatus that can be used in an image forming method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Intermediate transfer belt 3 Exposure device 4 Intermediate transfer belt cleaner 5 Primary transfer roll 5a Power supply 6 Neutralizing brush 11 Charging roll 12 Rotary developing device 12Y, 12M, 12C, 12K Developer 14 Photoconductor cleaner 21 Tension roll 22 Drive Roll 23 Backup roll 24 Secondary transfer roll 25 Cam mechanism T1 Primary transfer portion T2 Secondary transfer portion P Recording medium

Claims (2)

Least be non-crystalline polyester resin, the wear colorant and ester compound represented by the following general formula (1), by respectively dispersed in an aqueous medium, the resin particle dispersion, a colorant dispersion and an ester compound dispersion An emulsification step to be adjusted;
An agglomeration step of forming aggregated particles in a raw material dispersion containing the resin particle dispersion, the colorant dispersion, and the ester compound dispersion;
At least through a fusing step of fusing the aggregated particles by heating , the ester compound comprises the amorphous polyester resin and the colorant, and the ester compound with respect to 100 parts by weight of the amorphous polyester resin. A method for producing a toner for developing an electrostatic charge image, comprising producing 2 to 20 parts by weight of the toner for developing an electrostatic charge image.

[In the general formula (1), R ₁ , R ₂ and R ₃ are a group or an atom selected from the group consisting of a substituted or unsubstituted acyl group and a hydrogen atom, and R ₁ , R ₂ And R ₃ represents an acyl group having a hydroxyl group as a substituent and having 10 to 28 carbon atoms. ] The ester compound is a triester compound in which the R ₁ , R ₂ , and R ₃ are composed of the same acyl group having a hydroxyl group as a substituent and having 10 to 28 carbon atoms. 2. A method for producing a toner for developing an electrostatic charge image according to 1.