JP2021135399A - Method for manufacturing electrostatic charge image developing toner - Google Patents

Abstract

To provide a method for manufacturing electrostatic charge image developing toner excellent in balance between heat resistant storage and low temperature fixability and capable of suppressing the deterioration of printing durability and the bleed of a release agent even after being stored for a long time in high temperature and high humidity environment.SOLUTION: A method for manufacturing electrostatic charge image developing toner comprises steps of: preparing a suspension obtained by dispersing droplets of a polymerizable monomer composition including a polymerizable monomer, a colorant, a polar resin and a release agent in an aqueous medium including a water insoluble inorganic compound; and forming coloring resin particles by subjecting the suspension to polymerization reaction. The content of the polar resin is 0.8-2.5 mass parts to the polymerizable monomer of 100 mass parts; an agitator including a dispersion machine having the combination of a rotor and stator served as comb-tooth type concentric rings and a dispersion supply tank is used in the step of preparing the suspension; the rotor of the dispersion machine has a peripheral speed of 15-40 m/s; and the frequency of circulation of the dispersion circulating in the agitator is 10-30.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a method for producing a toner for developing an electrostatic charge image formed by an electrophotographic method, an electrostatic recording method, or the like.

In the electrophotographic method, an electrostatic charge image formed on a photoconductor is developed with toner to obtain a visible image, and if necessary, the toner image is transferred to a transfer material such as paper or OHP, and then the toner is transferred onto the transfer material. This is a method of fixing an image to obtain a copy or a printed matter.
In recent years, the speed of laser printers and copiers using electrophotographic methods has been increasing, and there is a demand for toners having better developability, transferability, and low-temperature fixability. Further, since the electrophotographic technology market is rapidly expanding to emerging countries, there is a demand for toner having excellent storage stability even in various usage environments such as temperature and humidity.

According to Patent Document 1, the applicant is a copolymer of (meth) acrylic acid ester and (meth) acrylic acid, and the acid value, weight average molecular weight Mw, and glass transition temperature are each within a specific range. It is disclosed that by incorporating a copolymer as a fixing aid into colored resin particles, a toner having an excellent balance between heat-resistant storage property and low-temperature fixing property and excellent printing durability under a wide range of environments can be obtained.

International Publication No. 2014/133032

However, when the toner disclosed in Patent Document 1 is stored in a high temperature and high humidity environment for a long period of about one month, the printing durability deteriorates or the image quality deteriorates due to the bleeding of the release agent. It turned out that there is.
The subject of the present disclosure is an electrostatic charge that has an excellent balance between heat-resistant storage and low-temperature fixability, and suppresses deterioration of printing durability and bleeding of a release agent even after long-term storage in a high-temperature and high-humidity environment. It is to provide the manufacturing method of the toner for image development.

The method for producing toner is roughly classified into a pulverization method and a polymerization method. The polymerization method includes an emulsification polymerization method, a suspension polymerization method and the like. It is known that the toner obtained by the polymerization method has a relatively high circularity and is therefore excellent in developability and transferability.
When the present inventor produces a toner containing a copolymer which is a polar resin and a release agent by a suspension polymerization method like the toner disclosed in Patent Document 1, the content of the polar resin is determined. It was also found that by adjusting the stirring conditions when preparing the suspension, it is possible to suppress the bleeding of the release agent and the deterioration of the printing durability after long-term storage in a high temperature and high humidity environment.

According to the present disclosure, droplets of a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, a polar resin and a mold release agent are dispersed in an aqueous medium containing a poorly water-soluble inorganic compound. A method for producing a toner for static charge image development, which comprises a step of preparing the suspension and a step of forming colored resin particles by subjecting the suspension to a polymerization reaction.
The content of the polar resin is 0.8 to 2.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
In the step of preparing the suspension,
A disperser having a combination of a rotor and a stator, which are comb-tooth type concentric rings, and a stirrer having a dispersion liquid supply tank are used.
The dispersion liquid containing the aqueous medium and the polymerizable monomer composition is supplied from the dispersion liquid supply tank to the disperser, stirred by the disperser, and then discharged to the dispersion liquid supply tank. The suspension is prepared by repeatedly circulating in the stirrer.
The peripheral speed of the rotor of the disperser is 15 to 40 m / s.
Provided is a method for producing a toner for static charge image development, wherein the number of circulations of the dispersion liquid calculated by the following formula is 10 to 30.
Number of times the dispersion liquid is circulated = {Flow rate of the dispersion liquid (liter / h) x Treatment time (h)} / Amount of dispersion liquid charged (liter)

In the above-mentioned production method of the present disclosure, the polar resin is a copolymer of at least one selected from acrylic acid ester and methacrylic acid ester and at least one selected from acrylic acid and methacrylic acid, and has an acid value. Is preferably 0.5 to 7.0 mgKOH / g, the weight average molecular weight Mw is 8,000 to 45,000, and the glass transition temperature is preferably 60 to 95 ° C.

In the above-mentioned production method of the present disclosure, it is preferable that the poorly water-soluble inorganic compound is an inorganic hydroxide.
In the above-mentioned production method of the present disclosure, it is more preferable that the poorly water-soluble inorganic compound is magnesium hydroxide.

In the above-mentioned production method of the present disclosure, it is preferable that the release agent is a monoester compound.

According to the manufacturing method of the present disclosure as described above, the balance between heat-resistant storage property and low-temperature fixability is excellent, and even after long-term storage in a high-temperature and high-humidity environment, the printing durability deteriorates and the release agent bleeds. It is possible to produce a toner for developing an electrostatic charge image in which the amount of noise is suppressed.

It is sectional drawing of an example of the stirring apparatus used in the manufacturing method of this disclosure.

1. 1. Method for Producing Toner for Electrostatic Image Development In the method for producing a toner for electrostatic charge image development in the present disclosure, at least a polymerizable monomer, a colorant, a polar resin and a release material are contained in an aqueous medium containing a poorly water-soluble inorganic compound. It comprises a step of preparing a suspension in which droplets of the polymerizable monomer composition containing a mold are dispersed, and a step of forming colored resin particles by subjecting the suspension to a polymerization reaction. This is a method for manufacturing toner for charge image development.
The content of the polar resin is 0.8 to 2.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
In the step of preparing the suspension,
A disperser having a combination of a rotor and a stator, which are comb-tooth type concentric rings, and a stirrer having a dispersion liquid supply tank are used.
The dispersion liquid containing the aqueous medium and the polymerizable monomer composition is supplied from the dispersion liquid supply tank to the disperser, stirred by the disperser, and then discharged to the dispersion liquid supply tank. The suspension is prepared by repeatedly circulating in the stirrer.
The peripheral speed of the rotor of the disperser is 15 to 40 m / s.
The number of circulations of the dispersion liquid calculated by the following formula is 10 to 30.
Number of times the dispersion liquid is circulated = {Flow rate of the dispersion liquid (liter / h) x Treatment time (h)} / Amount of dispersion liquid charged (liter)

In the present disclosure, the toner for developing an electrostatic charge image may be simply referred to as a toner.
Further, in the present disclosure, "~" in the numerical range means that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value.

The toner disclosed in Patent Document 1 is usually produced by a suspension polymerization method, and contains a polymerizable monomer, a colorant, a (meth) acrylic acid ester and a (meth) acrylic acid, which are polar resins. A suspension is prepared by dispersing droplets of the polymerizable monomer composition containing the copolymer of the above and a mold release agent in an aqueous medium containing a poorly water-soluble metal compound as a dispersion stabilizer. ing. When the toner disclosed in Patent Document 1 is stored in a high temperature and high humidity environment for a long period of about one month, the print durability deteriorates or the release agent bleeds, so that the formed image quality deteriorates. It turns out that there are cases.
Also in the production method of the present disclosure, droplets of the polymerizable monomer composition containing a polymerizable monomer, a colorant, a polar resin and a mold release agent are placed in an aqueous medium containing a poorly water-soluble inorganic compound. Disperse to prepare a suspension. However, in the production method of the present disclosure, the content of the polar resin is set within the above-mentioned specific range, and the stirring condition when preparing the suspension is set to the above-mentioned specific condition, so that the temperature is high over a long period of time. Even when stored in a damp environment, deterioration of printing durability and bleeding of the release agent can be suppressed.
In the toner obtained by the production method of the present disclosure, the bleeding of the release agent is suppressed because the surface of the toner is covered with a polar resin shell when the polar resin is contained in an amount within the specific range. It is presumed that particles are obtained. The polar resin in the droplet of the polymerizable monomer composition is considered to be present on the surface of the droplet because it has a relatively high affinity with the aqueous medium and easily moves to the interface with the aqueous medium. In the production method of the present disclosure, when the content of the polar resin is within the above-mentioned specific range, a shell of the polar resin is formed on the surface of the droplets of the polymerizable monomer composition, which is obtained after the polymerization step. It is presumed that the surface of the colored resin particles is also covered with a polar resin shell. Since the polar resin shell is hard to break in a high temperature and high humidity environment and the release agent in the colored resin particles is hard to permeate through the polar resin shell, the surface of the colored resin particles is covered with the polar resin shell. It is presumed that the bleeding of the release agent is suppressed even if the toner is stored in a high temperature and high humidity environment for a long period of time. As shown in Comparative Examples 5 and 6 described later, the conventional toner containing the polar resin has an insufficient content of the polar resin, so that a sufficient polar resin shell is not formed on the surface of the colored resin particles. , It is presumed that bleeding of the release agent had occurred.
In the toner obtained by the production method of the present disclosure, the deterioration of printing durability is suppressed because the metal compound derived from the poorly water-soluble inorganic compound used as the dispersion stabilizer is sufficiently removed. It is presumed that the surface of the colored resin particles is covered with a polar resin shell.
When a polar resin is contained in the polymerizable monomer composition, a poorly water-soluble inorganic compound having a high affinity for the polar resin is preferably used as the dispersion stabilizer. However, even if a poorly water-soluble inorganic compound is used as the dispersion stabilizer, when the polar resin is contained in the polymerizable monomer composition, the droplets of the polymerizable monomer composition have the polar resin on the surface. Therefore, the droplets are easily attracted to each other in the suspension, and the droplets of the polymerizable monomer composition are easily aggregated. In the conventional method, the droplets of the polymerizable monomer composition thus aggregated are present as the colored resin particles aggregated after the polymerization reaction. Therefore, in the cleaning step, even if an acid or an alkali is added to dissolve the poorly water-soluble inorganic compound in water to remove it, the water-soluble inorganic compound (typically a metal compound) is aggregated in the colored resin. It is presumed that it is not sufficiently removed because it is incorporated into the particles. In the production of toner, an external addition treatment for adhering an external additive is performed on the colored resin particles obtained after polymerization, if necessary. The agglomerated colored resin particles may be dissociated by the external addition treatment, but in any case, the metal compound derived from the poorly water-soluble inorganic compound remains on the surface of the obtained toner. If the metal compound remains on the surface of the toner in this way, it is presumed that when the toner is stored for a long period of time in a high temperature and high humidity environment, the printing durability deteriorates due to the remaining metal compound.
Further, even when the content of the polar resin is insufficient, the printing durability deteriorates when the toner is stored for a long period of time in a high temperature and high humidity environment. If the content of the polar resin is insufficient, as described above, a sufficient polar resin shell is not formed on the surface of the colored resin particles, and the toner is released when it is stored for a long period of time in a high temperature and high humidity environment. It is presumed that the printing durability deteriorates because the bleeding of the agent occurs and the bleeding mold release agent contaminates the members in the cartridge.
On the other hand, in the production method of the present disclosure, droplets of the polymerizable monomer composition were dispersed in the aqueous medium by using the polymerizable monomer composition containing the polar resin within the specific range. It is presumed that by preparing the suspension under the specific conditions, aggregation of droplets of the polymerizable monomer composition is suppressed and a polar resin shell is formed on the surface of the colored resin particles. .. As a result, in the obtained colored resin particles and the toner, the metal compound derived from the poorly water-soluble inorganic compound is hard to remain, and the release agent is hard to bleed on the toner surface, so that the contamination of the members in the cartridge is suppressed. Therefore, it is presumed that the printing durability is unlikely to deteriorate even when the toner is stored in a high temperature and high humidity environment for a long period of time.
Further, in the toner obtained by the production method of the present disclosure, since the droplets of the polymerizable monomer composition are difficult to aggregate, the obtained toner particles tend to be uniform and the particle size distribution is narrow. Therefore, the production method of the present disclosure By using the toner obtained by the above, a high quality image can be obtained.

The production method of the present disclosure is basically a suspension polymerization method, and is a step of preparing a suspension in which droplets of a polymerizable monomer composition are dispersed in an aqueous medium (hereinafter, a suspension is prepared). The step of forming colored resin particles by subjecting the suspension to a polymerization reaction (hereinafter, may be referred to as a polymerization step) is included at least. As the polymerizable monomer composition, those prepared in advance may be used, but the production method of the present disclosure may further include a step of preparing a polymerizable monomer composition, and may also be used. , Steps other than these may be further included.
Hereinafter, an example of the production method of the present disclosure having (1) a step of preparing a polymerizable monomer composition, (2) a step of preparing a suspension, and (3) a polymerization step will be described in detail. do. As long as it is technically possible, each step of the manufacturing method of the present disclosure may be carried out in a different order, or two or more steps may be carried out simultaneously as one step. For example, by simultaneously suspending the material of the polymerizable monomer composition while putting it into an aqueous medium, the preparation of the polymerizable monomer composition and the preparation of the suspension are performed simultaneously in one step. You may.

(1) Step of preparing a polymerizable monomer composition In this step, at least a polymerizable monomer, a colorant, a polar resin and a mold release agent are contained, and if necessary, a charge control agent and a molecular weight adjustment are made. A polymerizable monomer composition containing other materials such as an agent is prepared. The polymerizable monomer composition is prepared by mixing each material, and for the mixing, for example, a media type disperser is used.

[Polymerizable monomer]
In the present disclosure, the polymerizable monomer means a monomer having a polymerizable functional group, and the polymerizable monomer is polymerized to form a binder resin.
It is preferable to use a monovinyl monomer as the main component of the polymerizable monomer. Examples of the monovinyl monomer include styrene; styrene derivatives such as vinyltoluene and α-methylstyrene; acrylic acid and methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2. -Acrylate esters such as dimethylaminoethyl acrylate; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and 2-dimethylaminoethyl methacrylate; nitriles such as acrylonitrile and methacrylonitrile. Compounds; amide compounds such as acrylamide and methacrylicamide; olefins such as ethylene, propylene and butylene;
These monovinyl monomers can be used alone or in combination of two or more. Of these, at least one selected from the group consisting of styrene, styrene derivatives, acrylic acid, acrylic acid ester, methacrylic acid and methacrylic acid ester is preferably used as the monovinyl monomer.

In order to improve the heat-resistant storage stability of the obtained toner, it is preferable to use a crosslinkable polymerizable monomer together with the monovinyl monomer. The crosslinkable polymerizable monomer refers to a monomer having two or more polymerizable functional groups. Examples of the crosslinkable polymerizable monomer include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; and alcohols having two or more hydroxyl groups such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate. Ester compounds in which two or more carboxylic acids are ester-bonded; other divinyl compounds such as N, N-divinylaniline, and divinyl ether; compounds having three or more vinyl groups; and the like can be mentioned.
These crosslinkable polymerizable monomers can be used alone or in combination of two or more.
The crosslinkable polymerizable monomer is usually used in a ratio of 0.1 to 5 parts by mass, preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the monovinyl monomer.

Further, it is preferable to use a macromonomer as a part of the polymerizable monomer because the balance between the heat-resistant storage property and the low-temperature fixability of the obtained toner is improved. The macromonomer has a polymerizable carbon-carbon unsaturated double bond at the end of the molecular chain and is a reactive oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000. The macromonomer preferably gives a polymer having a Tg higher than the glass transition temperature (Tg) of the polymer obtained by polymerizing the monovinyl monomer.
The macromonomer is preferably used in a proportion of 0.03 to 5 parts by mass, more preferably 0.05 to 1 part by mass with respect to 100 parts by mass of the monovinyl monomer.

The total amount of the polymerizable monomer contained in the polymerizable monomer composition is preferably 60 to 95 parts by mass, more preferably 70 to 90 parts by mass, based on the total solid content contained in the polymerizable monomer composition. Is.
In the present disclosure, the solid content is anything other than the solvent, and for example, a liquid monomer and a substance dissolved in the solvent are included in the solid content.

[Colorant]
The colorant contained in the polymerizable monomer composition is not particularly limited, and for example, black, cyan, yellow, and magenta colorants can be used.
As the black colorant, for example, carbon black, titanium black, and magnetic powders such as iron zinc oxide and nickel oxide can be used.
As the cyan colorant, for example, a copper phthalocyanine compound, a derivative thereof, an anthraquinone compound and the like are used, and specifically, C.I. I. Pigment Blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17: 1, 60 and the like.
As the yellow colorant, for example, compounds such as azo pigments such as monoazo pigments and disazo pigments and condensed polycyclic pigments are used. Specifically, C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 74, 83, 93, 97, 120, 138, 155, 180, 181, 185, 186, and 213.
As the magenta colorant, for example, compounds such as azo pigments such as monoazo pigments and disazo pigments and condensed polycyclic pigments are used. Specifically, C.I. I. Pigment Red 31, 48, 57: 1, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 150, 163, 170, 184, 185, 187, 202, 206, 207, 209, 237, 238, 251, 254, 255, 269 and C.I. I. Pigment Violet 19 and the like.
In the present disclosure, each colorant can be used alone or in combination of two or more.
The colorant is preferably used in a ratio of 1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

[Polar resin]
In the present disclosure, the polar resin is selected from the group consisting of polymers containing repeating units containing heteroatoms. Specific examples of the polar resin include acrylic resins, polyester resins, and vinyl resins containing heteroatoms.
The polar resin may be a homopolymer or a copolymer of a heteroatom-containing monomer, or may be a copolymer of a heteroatom-containing monomer and a heteroatom-free monomer. .. When the polar resin is a copolymer of a hetero atom-containing monomer and a hetero atom-free monomer, it is easy to control the particle size of the colored resin particles, and the resulting toner bleeds the release agent. The proportion of the hetero atom-containing monomer unit is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 70% by mass or more, based on 100% by mass of all the repeating units constituting the copolymer. Is 90% by mass or more.

Examples of the hetero atom-containing monomer used in the polar resin include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) acrylate. , Isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, sec-pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate , N-hexyl (meth) acrylate, isohexyl (meth) acrylate, neohexyl (meth) acrylate, sec-hexyl (meth) acrylate, tert-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate Alkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, dimethylaminoethyl (meth) ) Acrylate, diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 4-hydroxybutyl acrylate (meth) acrylic acid ester such as glycidyl ether, and monomer having (meth) acryloyl group such as (meth) acrylic acid. That is, (meth) acrylic monovinyl monomer; aromatic vinyl monomer containing a hetero atom such as styrene halide and styrene sulfonic acid; carboxylic acid vinyl ester monomer such as vinyl acetate; halogenation of vinyl chloride and the like. Vinyl monomer; Halogenized vinylidene monomer such as vinylidene chloride; Vinylpyridine monomer; Acrylate unsaturated carboxylic acid such as crotonic acid, silicic acid, itaconic acid, fumaric acid, maleic acid, butentricarboxylic acid, etc. Carboxy group-containing monomers such as quanta; epoxy group-containing monomers such as allyl glycidyl ether and the like can be mentioned. In the present disclosure, (meth) acrylate represents each of acrylate and methacrylate, and (meth) acrylic represents each of acrylic and methacryl. These heteroatom-containing monomers can be used alone or in combination of two or more.

Examples of the hetero atom-free monomer used in the polar resin include aromatic vinyl monomers containing no hetero atom such as styrene, vinyltoluene, α-methylstyrene, and p-methylstyrene; ethylene, propylene, and the like. Monoolefin monomers such as butylene; diene monomers such as butadiene and isoprene can be mentioned. These heteroatom-free monomers can be used alone or in combination of two or more.

The polar resin contains a polar group in which the hetero atom-containing monomer contains at least one polar group selected from a carboxyl group, a hydroxyl group, a sulfonic acid group, an amino group, a polyoxyethylene group and an epoxy group. It is preferable to contain a monomer unit from the viewpoint that the particle size of the colored resin particles can be easily controlled and the bleeding of the release agent can be easily suppressed in the obtained toner. As the polar group, at least one selected from a carboxyl group and a hydroxyl group is preferable.
Examples of the polar group-containing monomer include carboxyls of ethylenically unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, crotonic acid, silicic acid, itaconic acid, fumaric acid, maleic acid, and butentricarboxylic acid. Group-containing monomer; hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; sulfonic acid group-containing such as styrene sulfonic acid Monomer; Amino group-containing monomer such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; Polyoxyethylene group-containing monomer such as methoxypolyethylene glycol (meth) acrylate; Glycidyl (meth) acrylate , Allyl glycidyl ether, 4-hydroxybutyl acrylate glycidyl ether and other epoxy group-containing monomers and the like can be mentioned. These polar group-containing monomers can be used alone or in combination of two or more.
When the polar resin contains a polar group-containing monomer unit, the polar resin is located at the end of the main chain or side chain, or is bonded to the main chain or side chain in a pendant shape. Is preferable because it is easy to be arranged on the surface of the droplets of the polymerizable monomer composition, the particle size of the colored resin particles is easily controlled, and the bleeding of the release agent is easily suppressed in the obtained toner.

When the polar resin does not contain the polar group-containing monomer unit, the hetero atom-containing monomer unit contained in the polar resin has high compatibility with the polymerizable monomer and is colored resin particles. It is preferable to contain a monomer unit derived from an alkyl (meth) acrylate because it is easy to control the particle size of the acrylate and it is easy to suppress the bleeding of the release agent in the obtained toner. , The alkyl group more preferably contains a monomer unit derived from an alkyl (meth) acrylate having 3 or less carbon atoms, and is simply derived from at least one selected from methyl (meth) acrylate and ethyl (meth) acrylate. It is even more preferable to include a metric unit, and even more preferably to include a monomer unit derived from methyl (meth) acrylate.

The polar resin is particularly compatible with the polymerizable monomer, and the particle size of the colored resin particles can be easily controlled, and the resulting toner can easily suppress the bleeding of the release agent. A copolymer of at least one selected from acrylic acid ester and methacrylic acid ester and at least one selected from acrylic acid and methacrylic acid is preferable, and the copolymer of acrylic acid ester, methacrylic acid ester, and acrylic acid is preferable. Coalescence is more preferred. In the present disclosure, such a copolymer of (meth) acrylic acid ester and (meth) acrylic acid may be referred to as an acrylic copolymer.
In the acrylic copolymer, examples of the (meth) acrylic acid ester include those similar to the (meth) acrylic acid ester used in the heteroatom-containing monomer. In the acrylic copolymer, the (meth) acrylic acid ester may or may not contain the polar group, but those containing no polar group are preferable, and alkyl is particularly preferable. (Meta) acrylate is preferred. The acrylic acid ester used in the acrylic copolymer is preferably at least one selected from the group consisting of ethyl acrylate, n-propyl acrylate, isopropyl acrylate and n-butyl acrylate, and more preferably. At least one selected from ethyl acrylate and n-butyl methacrylate. The methacrylic ester used in the acrylic copolymer is preferably at least one selected from the group consisting of methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate and n-butyl methacrylate, and more preferably. It is methyl methacrylate.

The acrylic copolymer has high compatibility with the polymerizable monomer, and it is easy to control the particle size of the colored resin particles, and it is easy to suppress the bleeding of the release agent in the obtained toner. The ratio of (meth) acrylic acid to 100% by mass of the total amount of (meth) acrylic acid ester and (meth) acrylic acid used in the synthesis of the acrylic copolymer is preferably 0.05 to 1% by mass. It is more preferably 0.1 to 0.6% by mass, and even more preferably 0.3 to 0.5% by mass.

The acrylic copolymer has high compatibility with the polymerizable monomer, and it is easy to control the particle size of the colored resin particles, and it is easy to suppress the bleeding of the release agent in the obtained toner. It is preferable that the copolymer is a monomer containing 50.0% by mass or more of methyl methacrylate with respect to 100% by mass of the total mass of the monomers used in the synthesis of the copolymer. The acrylic copolymer is more preferably a monomer copolymer containing 50.0 to 99.9% by mass of methyl methacrylate and 0.1 to 5.0% by mass of (meth) acrylic acid. Yes, more preferably, it is a copolymer of a monomer containing 50.0 to 99.0% by mass of methyl methacrylate and 0.1 to 5.0% by mass of (meth) acrylic acid, and even more preferably. , Methyl methacrylate 50.0 to 98.0% by mass, alkyl (meth) acrylate 1.0 to 5.0% by mass different from methyl methacrylate, and (meth) acrylic acid 0.1 to 5.0% by mass. It is a copolymer of a monomer containing, and particularly preferably, methyl methacrylate is 50.0 to 98.0% by mass, and alkyl (meth) acrylate different from methyl methacrylate is 1.0 to 5.0% by mass. It is a monomer copolymer containing 0.2 to 3.0 mass of (meth) acrylic acid.
As the alkyl (meth) acrylate different from methyl methacrylate, at least one selected from ethyl acrylate and butyl acrylate is preferable because the glass transition point can be controlled.

The acrylic copolymer may contain a small amount of monomer units derived from other monomers different from both the (meth) acrylic acid ester and the (meth) acrylic acid. The content ratio of the other monomers is used in the synthesis of the acrylic copolymer because it is easy to control the particle size of the colored resin particles and the bleeding of the release agent is easily suppressed in the obtained toner. Of the total amount of the monomers to be obtained, it is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, and most preferably does not contain the other monomers.
Examples of the other monomer include the heteroatom-free monomer and the heteroatom-containing monomer other than the (meth) acrylic monovinyl monomer.

The acid value of the polar resin is preferably 0.5 to 7.0 mgKOH / g, more preferably 1.0 to 5.0 mgKOH / g, and even more preferably 1.5 to 3.0 mgKOH / g. be. When the acid value of the polar resin is at least the lower limit value, the heat-resistant storage stability, low-temperature fixability, and printing durability of the toner can be improved. When the acid value of the polar resin is not more than the upper limit value, the particle size of the colored resin particles can be easily controlled.
In this disclosure, the acid value is a value measured in accordance with JIS K 0070, which is a standard oil and fat analysis method established by the Japanese Industrial Standards Committee (JICS).

The weight average molecular weight (Mw) of the polar resin is preferably 8,000 to 45,000, more preferably 9,000 to 45,000, and even more preferably 10,000 to 40,000. When the weight average molecular weight (Mw) of the polar resin is at least the lower limit value, the heat-resistant storage stability and durability of the toner can be improved, and when it is at least the upper limit value, the fixing temperature of the toner is raised. Can be suppressed.
In the present disclosure, the weight average molecular weight (Mw) of the polymer can be determined by GPC in terms of polystyrene using a sample dissolved in tetrahydrofuran (THF).

The glass transition temperature (Tg) of the polar resin is preferably 60 to 95 ° C, more preferably 65 to 90 ° C, and even more preferably 70 to 80 ° C.
When the glass transition temperature of the polar resin is at least the lower limit value, the heat-resistant storage stability of the toner can be improved, and when it is at least the upper limit value, the low-temperature fixability of the toner can be improved.
The glass transition temperature Tg of the polar resin can be determined according to, for example, ASTM D3418-82. Specifically, the sample is heated at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter (manufactured by Seiko Electronics Co., Ltd .: SSC5200), and the maximum thermal peak of the DSC curve obtained in the process is obtained. The indicated temperature can be the glass transition temperature.

As the polar resin, a commercially available one can be used, but the monomer containing the heteroatom-containing monomer can be subjected to a solution polymerization method, an aqueous solution polymerization method, an ion polymerization method, a high-temperature high-pressure polymerization method, or a suspended weight. It can be produced by polymerizing by a known method such as legality.
When the polar resin is a copolymer, the copolymer may be a random copolymer, a block copolymer, or a graft copolymer, but it may be a random copolymer. preferable.
Further, the polar resin is preferably pulverized more finely from the viewpoint of improving the solubility.

The content of the polar resin is 0.8 to 2.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer. When the content of the polar resin is at least the lower limit value, the particle size of the colored resin particles can be easily controlled, and the bleeding of the release agent can be suppressed in the obtained toner. On the other hand, when the content of the polar resin is not more than the upper limit value, it is possible to suppress an increase in the fixing temperature of the toner. The content of the polar resin is preferably 1.0 to 2.2 parts by mass, and more preferably 1.0 to 2.0 parts by mass.

[Release agent]
The release agent can be used without particular limitation as long as it is generally used as a release agent for toner. When the polymerizable monomer composition contains a release agent, the obtained toner has good releasability from the fixing roll.

In the present disclosure, a monoester compound is preferably used as the release agent. By using a monoester compound as a release agent, the low temperature fixability of the toner can be improved.
As the monoester compound, for example, a monoester compound represented by the following formula (1) can be preferably used.
R ^1- COO-R ² formula (1)
In the formula (1), R ¹ represents a linear alkyl group having 15 to 21 carbon atoms, and R ² represents a linear alkyl group having 16 to 22 carbon atoms. R ¹ and R ² may be the same group or different groups from each other. In the monoester compound represented by the formula (1), the difference between the carbon number of the raw material fatty acid (that is ^{, the carbon number of R 1} plus 1) and the carbon number of the raw material alcohol (that is, the carbon number of ^{R 2) is} , 0-6, more preferably 4-6.

Examples of the monoester compound represented by the formula (1) include behenic palmitate (C ₁₅ H _31- COO-C ₂₂ H ₄₅ ) and behenic stearate (C ₁₇ H _35- COO-C ₂₂ H ₄₅ ). , Behenic acid behenic acid (C ₁₉ H _39- COO-C ₂₂ H ₄₅ ), Behenic acid behenate (C ₂₁ H _43- COO-C ₂₂ H ₄₅ ), Eikosyl palmitate (C ₁₅ H _31- COO-C ₂₀ H ₄₁₎ ), Eikosyl stearate (C ₁₇ H _35- COO-C ₂₀ H ₄₁ ), Eikosyl eikosanate (C ₁₉ H _39- COO-C ₂₀ H ₄₁ ), Eikosyl behenate (C ₂₁ H _43- COO-C ₂₀ H) ₄₁ ), stearyl stearate (C ₁₇ H _35- COO-C ₁₈ H ₃₇ ), stearyl eicosanate (C ₁₉ H _39- COO-C ₁₈ H ₃₇ ), stearyl behenate (C ₂₁ H _43- COO-C ₁₈₎ H ₃₇ ), hexadecyl eikosanate (C ₁₉ H _39- COO-C ₁₆ H ₃₃ ), hexadecyl behenate (C ₂₁ H _43- COO-C ₁₆ H ₃₃ ) and the like. Among these monoester compounds, behenic stearate, behenic palmitate, and stearyl behenate are more preferable.

The monoester compound represented by the above formula (1) is, for example, a synthesis method by an oxidation reaction, synthesis from a carboxylic acid and its derivative, an ester group introduction reaction represented by a Michael addition reaction, a carboxylic acid compound and an alcohol. It can be produced by a method utilizing a dehydration condensation reaction from a compound, a reaction between an acid halide and an alcohol compound, an ester exchange reaction, or the like. Further, a catalyst can be appropriately used for producing the monoester compound represented by the formula (1). As the catalyst, general acidic or alkaline catalysts used in the esterification reaction, for example, zinc acetate, titanium compounds and the like are preferable. After the esterification reaction, the target product may be purified by recrystallization, distillation or the like.

Examples of the release agent that can be used in the present disclosure include pentaerythritol tetrabehenate, pentaerythritol tetrapalminate, and pentaeristol tetrasteer, in addition to the monoester compound represented by the above formula (1). Pentaerythritol ester compounds such as rates, hexaglycerin octabehenate, pentaglycerin heptabehenate, tetraglycerin hexabehenate, triglycerin pentabehenate, diglycerin tetrabehenate, glycerin tribehenate, etc. Ester wax such as glycerin ester compound; hydrocarbon wax such as polyethylene wax, polypropylene wax, Fishertroph wax, petroleum wax; natural wax such as jojoba; mineral wax such as ozokelite; and the like.

The release agent used in the present disclosure has a melting point of preferably 60 to 75 ° C, more preferably 63 to 72 ° C, and even more preferably 65 to 70 ° C. When the melting point of the release agent is at least the lower limit value, the heat-resistant storage stability of the toner can be improved, and when it is at least the upper limit value, a decrease in the fixing temperature of the toner can be suppressed.

The acid value of the release agent used in the present disclosure is preferably 1.0 mgKOH / g or less, more preferably 0.6 mgKOH / g or less, still more preferably 0.3 mgKOH / g or less. When the acid value of the release agent is not more than the above upper limit value, the storage stability of the toner can be improved.

The hydroxyl value of the release agent used in the present disclosure is preferably 10 mgKOH / g or less, more preferably 6 mgKOH / g or less, still more preferably 3 mgKOH / g or less. When the hydroxyl value of the release agent is not more than the above upper limit value, the storage stability of the toner can be improved.
In this disclosure, the hydroxyl value is a value measured in accordance with JIS K 0070, which is a standard oil and fat analysis method established by the Japanese Industrial Standards Committee (JICS).
The release agent used in the present disclosure preferably has both an acid value and a hydroxyl value of not more than the above-mentioned preferable upper limit values.

The release agent is usually used in a proportion of 8 to 40 parts by mass, preferably 11 to 35 parts by mass, and more preferably 15 to 30 parts by mass with respect to 100 parts by mass of the polymerizable monomer. When the content of the release agent is at least the above lower limit value, the releasability of the toner from the fixing roll can be improved, and when it is at least the above upper limit value, the heat storage stability and durability are deteriorated. It can be suppressed.

[Electrification control agent]
The polymerizable monomer composition preferably contains a positively charged or negatively charged charge control agent in order to improve the chargeability of the toner.
The charge control agent is not particularly limited as long as it is generally used as a charge control agent for toner, but among the charge control agents, it has high compatibility with the polymerizable monomer and has stable chargeability. Since (charging stability) can be imparted to the toner particles, a positively charged or negatively charged charge control resin is preferable, and from the viewpoint of obtaining a positively chargeable toner, a positively chargeable charge control resin is used. More preferably used.

As the positively charged or negatively charged charge control resin, a functional group-containing copolymer can be used. As the positively chargeable charge control resin, for example, a functional group-containing copolymer containing a structural unit containing a functional group such as an amino group, a quaternary ammonium group or a quaternary ammonium salt-containing group can be used. , Polyamine resin, quaternary ammonium group-containing copolymer, quaternary ammonium base-containing copolymer and the like. As the negatively charged charge control resin, for example, a functional group-containing copolymer containing a structural unit containing a functional group such as a sulfonic acid group, a sulfonate-containing group, a carboxylic acid group or a carboxylic acid salt-containing group is used. Examples thereof include a sulfonic acid group-containing copolymer, a sulfonic acid base-containing copolymer, a carboxylic acid group-containing copolymer, and a carboxylic acid base-containing copolymer.
The functional group-containing copolymer used as a positively or negatively charged charge control resin is said to have high compatibility with a polymerizable monomer and excellent polymerization stability. The ratio of the functional group-containing structural unit in the functional group-containing copolymer is preferably 10% by mass or less, and more preferably 5% by mass or less. On the other hand, from the viewpoint of improving the charging stability and storage stability of the toner, the ratio of the functional group-containing constituent units in the functional group-containing copolymer is preferably 0.5% by mass or more. When the charge control resin contains a sufficient functional group, the charge control resin is easily localized near the surface of the colored resin particles, and the charge control resin functions like a shell of the colored resin particles, so that the toner It is estimated that the storage stability of the resin will be improved.

The functional group-containing copolymer used as a positively or negatively charged charge control resin has high compatibility with the polymerizable monomer, and the charge amount can be easily adjusted by the addition amount. A styrene-acrylic resin is preferable.

The functional group-containing copolymer used as a positively or negatively charged charge control resin preferably has a glass transition temperature (Tg) of 50 to 110 ° C., preferably 60 to 100 ° C. Is more preferable. When the glass transition temperature (Tg) of the functional group-containing copolymer is within the above range, the storage stability of the toner can be improved. Since the functional group-containing copolymer can be easily localized near the surface of the colored resin particles and can function like a shell, when the Tg of the functional group-containing copolymer is within the above range, Tg It is presumed that the storage stability of the toner is improved when the amount is sufficiently high.
The glass transition temperature (Tg) of the functional group-containing copolymer is measured by the same method as the glass transition temperature (Tg) of the polar resin described above.

Further, as the charge control agent, a charge control resin and a charge control agent other than the charge control resin may be used in combination.
Examples of other positively charged charge control agents include niglosin dyes, quaternary ammonium salts, triaminotriphenylmethane compounds, imidazole compounds and the like.
Examples of other negatively charged charge control agents include azo dyes containing metals such as Cr, Co, Al, and Fe, metal salicylate compounds, and metal alkyl salicylate compounds.
The charge control agent may be used alone or in combination of two or more.

In the present disclosure, the charge control agent is usually used in a ratio of 0.01 to 10 parts by mass, preferably 0.03 to 8 parts by mass with respect to 100 parts by mass of the monovinyl monomer. When the content of the charge control agent is 0.01 parts by mass or more, the generation of fog can be suppressed, while when the content is 10 parts by mass or less, printing stains can be suppressed.

[Molecular weight modifier]
The polymerizable monomer composition preferably further contains a molecular weight modifier. The molecular weight adjusting agent is not particularly limited as long as it is generally used as a molecular weight adjusting agent for toner. For example, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, 2, 2, 4 , 6,6-Pentamethylheptane-4-thiol and other mercaptans; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N'-dimethyl-N, N'-diphenylthiuram disulfide, N, N Thiolm disulfides such as'-dioctadecyl-N, N'-diisopropylthiuram disulfide; and the like can be mentioned. These molecular weight adjusting agents may be used alone or in combination of two or more.
The molecular weight adjusting agent is usually used in a ratio of 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

(2) Step of preparing a suspension In this step, a suspension in which droplets of the polymerizable monomer composition are dispersed in an aqueous medium is prepared.
The polymerizable monomer composition is put into an aqueous medium containing a poorly water-soluble inorganic compound as a dispersion stabilizer, and the polymerizable monomer composition is stirred and dispersed in the aqueous medium. Droplets of the composition can be formed.

The aqueous medium used in the present disclosure contains a poorly water-soluble inorganic compound as a dispersion stabilizer and a solvent. The poorly water-soluble inorganic compound has a high affinity with the polar resin. Therefore, by using a poorly water-soluble inorganic compound as the dispersion stabilizer, when the polymerizable monomer composition containing the polar resin is dispersed in an aqueous medium, the polar resin becomes a polymerizable monomer. The composition tends to be unevenly distributed on the surface of the droplets, whereby the poorly water-soluble inorganic compound tends to coat the droplets of the polymerizable monomer composition more easily, so that uniform droplets are easily formed. Further, the poorly water-soluble inorganic compound is preferable because it is easily removed by a cleaning step described later and the residual amount of the dispersion stabilizer in the toner is easily reduced.
Examples of the poorly water-soluble inorganic compound include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate, and magnesium carbonate; phosphates such as calcium phosphate; aluminum oxide, titanium oxide, and the like. Metal oxides; inorganic hydroxides such as metal hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide and ferric hydroxide; and the like. Among them, inorganic hydroxides are preferable, metal hydroxides are more preferable, and magnesium hydroxide is particularly preferable.
These poorly water-soluble inorganic compounds may be used alone or in combination of two or more.
In the present disclosure, the poorly water-soluble inorganic compound is preferably an inorganic compound having a solubility in 100 g of water of 0.5 g or less.
The poorly water-soluble inorganic compound is usually used in a ratio of 0.1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

As the solvent contained in the aqueous medium, a solvent containing water as a main component is used. Normally, ion-exchanged water is used, but a hydrophilic organic solvent such as methanol or ethanol may be added as long as the polymerization is not inhibited. Further, it is preferable that the aqueous medium is a colloid in which a poorly water-soluble inorganic compound is dispersed in a solvent.
The solvent contained in the aqueous medium is usually used in a ratio of 100 to 3000 parts by mass, preferably 200 to 2000 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

In the production method of the present disclosure, the polymerizable monomer composition is obtained by stirring the dispersion liquid containing the aqueous medium and the polymerizable monomer composition under specific conditions using a stirring device described later. Form a droplet of
Further, a polymerization initiator may be added to the dispersion liquid before the dispersion liquid is injected into the dispersion liquid supply tank. The polymerization initiator may be contained in the suspension used in the polymerization step described later, may be added to the dispersion liquid before being stirred by the stirring device, or the suspension obtained by stirring with the stirring device. It may be added to the liquid or added to the polymerizable monomer composition before being charged into the aqueous medium.
Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate: 4,4'-azobis (4-cyanovaleric acid) and 2,2'-azobis (2-methyl-N- (2-methyl-N- (2-methyl-N-)). Hydroxyethyl) propionamide), 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'-azobisisobutyronitrile And other azo compounds; di-t-butyl peroxide, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxydiethylacetate, t-hexylperoxy-2-ethylbutanoate. , Diisopropylperoxydicarbonate, di-t-butylperoxyisobutyrate, organic peroxides such as t-butylperoxyisobutyrate and the like. In addition, a redox initiator that is a combination of these polymerization initiators and a reducing agent can also be mentioned.
The polymerization initiators can be used alone or in combination of two or more.
As the polymerization initiator, among others, it is easy to dissolve in the droplets of the polymerizable monomer composition, the amount of the residual polymerizable monomer can be reduced, and the printing durability of the toner can be improved. Therefore, an organic peroxide is preferable, a peroxy ester is preferable, and a non-aromatic peroxy ester, that is, a peroxy ester having no aromatic ring is more preferable.
The polymerization initiator is preferably used in a proportion of 0.1 to 20 parts by mass, more preferably 0.3 to 15 parts by mass, still more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the monovinyl monomer. ..

In the production method of the present disclosure, a dispersion liquid containing the aqueous medium and the polymerizable monomer composition is dispersed with a disperser having a combination of a rotor and a stator, which are comb-toothed concentric rings. Stir using a stirrer having a liquid supply tank. In the disperser provided in the stirrer, the rotor is rotated at high speed to flow the dispersion liquid from the inside of the rotor to the outside of the stator, and the dispersion liquid is agitated in the gap between the rotor and the stator.
FIG. 1 shows a schematic cross-sectional view of an example of the stirring device used in the manufacturing method of the present disclosure. The stirring device 10 shown in FIG. 1 has a dispersion liquid supply tank 1 and a horizontal multi-stage in-line disperser 2, and the disperser 2 has a rotor 4 which is a comb-tooth type concentric ring in a casing 3. It has a combination with the stator 5. In the disperser 2, the rotor 4 is rotated at high speed by driving the rotating shaft 6, and the dispersion liquid is circulated from the inside of the rotor 4 to the outside of the stator 5, in the gap between the rotor 4 and the stator 5. Stir the dispersion. In the disperser 2 shown in FIG. 1, the combination of the rotor 4 and the stator 5 is arranged in three stages, but the stirring device used in the present disclosure is not limited to this, and may be one stage. It may be a multi-stage of two or more stages. From the viewpoint of narrowing the particle size distribution of the obtained colored resin particles, it is preferably multi-step, more preferably two-step or three-step, and particularly preferably three-step. The number of layers of the rotor and the stator in the combination of the rotor 4 and the stator 5 and the number of teeth of the rotor and the stator are appropriately selected according to the particle size of the toner to be manufactured, and are not particularly limited. However, when the combination of the rotor 4 and the stator 5 is arranged in multiple stages, the number of teeth of the rotor 4 and the stator 5 closest to the injection port side of the dispersion liquid is the other rotor 4 and the number of teeth of the stator 5. It is preferable that the number of teeth of the stator 5 is smaller than the number of teeth. For example, the arrangement of the combination of the rotor 4 and the stator 5 in the disperser 2 is three stages in the order of coarse teeth, middle teeth, and fine teeth from the injection port side to the outlet side of the dispersion liquid. , 3 stages in the order of middle teeth, middle teeth, 3 stages in the order of coarse teeth, fine teeth, fine teeth, 2 stages in the order of coarse teeth, middle teeth, and 2 stages in the order of coarse teeth, fine teeth It is preferable to be one of them.

In the stirring device 10, when the dispersion liquid containing the aqueous medium and the polymerizable monomer composition is injected into the dispersion liquid supply tank 1, the dispersion liquid is supplied from the dispersion liquid supply tank 1 to the disperser 2. After being agitated by the disperser 2, the liquid is repeatedly discharged to the dispersion liquid supply tank 1 to circulate in the agitator 10. In the stirring device 10, the dispersion liquid in the dispersion liquid supply tank 1 is supplied to the disperser 2 via the inner nozzle (not shown) and the dispersion liquid supply line 7. The dispersion liquid stirred by the disperser 2 is returned to the dispersion liquid supply tank 1 via the circulation line 8. The dispersion liquid is circulated in the stirring device 10 until the number of circulations described later is reached, and then is supplied to the polymerization reactor through the supply line 9 to the polymerization reactor.
The method of feeding the dispersion liquid is not particularly limited, and examples thereof include a method using a liquid feeding pump. Further, the internal pressure of the disperser can be adjusted by adjusting the flow rate of the dispersion liquid discharged from the disperser. The internal pressure of the disperser is preferably 0.01 to 15 MPa, more preferably 0.05 to 10 MPa, still more preferably 0.1 to 5 MPa. By keeping the internal pressure of the disperser within the above range, it is possible to efficiently form fine droplets while suppressing the generation of bubbles due to cavitation.

In the stirring device used in the manufacturing method of the present disclosure, the rotation axis of the disperser may be a horizontal type extending in the horizontal direction or a vertical type extending in the direction of gravity. ..
In the manufacturing method of the present disclosure, a commercially available stirrer can be used. For example, a horizontal multi-stage in-line disperser such as a milder (: product name) manufactured by Pacific Machinery & Engineering Co., Ltd., a Cavitron (: product name) manufactured by Eurotech Co., Ltd., and an in-line disperser manufactured by IKA (for example, DISPAX-REACTOR). (Registered trademark) DRS (: trade name), etc.) and other vertical multi-stage in-line dispersers can be mentioned.

In the manufacturing method of the present disclosure, the peripheral speed of the rotor of the disperser is 15 to 40 m / s, and the number of circulations of the dispersion liquid calculated by the following formula (I) is 10 to 30.
Equation (I)
Number of times the dispersion liquid is circulated = {Flow rate of the dispersion liquid (liter / h) x Treatment time (h)} / Amount of dispersion liquid charged (liter)
Here, the peripheral speed of the rotor means the tip speed of the rotor. The number of times the dispersion liquid circulates means the number of times the dispersion liquid circulates in the disperser. That is, by multiplying the flow rate (liter / h) of the dispersion liquid in the disperser by the processing time (h) by the disperser, the total amount of processing processed by the disperser can be obtained. By dividing this total processing amount by the amount of the dispersion liquid charged (liter), the number of circulations of the dispersion liquid can be calculated.
In the manufacturing method of the present disclosure, by setting the peripheral speed of the rotor to 15 m / s or more and the number of circulations to 10 or more, the printing durability when the toner is stored for a long period of time in a high temperature and high humidity environment is maintained. Deterioration can be suppressed. Further, in the manufacturing method of the present disclosure, deterioration of toner productivity is suppressed by setting the number of circulations to 30 or less. Further, in the manufacturing method of the present disclosure, the peripheral speed of the rotor is set to 40 m / s or less from the viewpoint of convenience that a general disperser can be used.
The peripheral speed of the rotor is preferably 15 to 35 m / s, more preferably 15 to 30 m / s, and even more preferably 15 to 25 m / s.
The number of circulations is preferably 10 to 25, more preferably 10 to 20.

(3) Polymerization Step In this step, colored resin particles are formed by subjecting the suspension obtained in the step of preparing the suspension to a polymerization reaction.
It is preferable to further add a water-soluble oxoacid salt to the suspension during the polymerization reaction. By adding a water-soluble oxoacid salt at the time of polymerization, the aggregation of droplets and the generation of fine powder can be suppressed, and the particle size distribution can be narrowed. Examples of the water-soluble oxoate include borates, phosphates, sulfates, carbonates, silicates, nitrates and the like, and preferably at least selected from the group consisting of borates and phosphates. One type, more preferably borate, is used. Examples of the borate include sodium tetrahydroborate, potassium tetrahydroborate, sodium tetraborate, sodium metaborate, sodium metaborate, sodium peroxoborate, potassium metaborate, and hydrates of these borates. Can be mentioned. Examples of the phosphate include sodium phosphinate, sodium phosphonate, sodium hydrogen phosphonate, sodium phosphate, disodium hydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium hexametaphosphate, and hypophosphoric acid. Sodium, sodium diphosphate, disodium dihydrogen diphosphate, sodium triphosphate, cyclo-sodium tetraphosphate, potassium phosphite, potassium phosphonate, potassium hydrogen phosphonate, potassium phosphate, dipotassium hydrogen phosphate, Examples thereof include potassium dihydrogen phosphate, potassium diphosphate, potassium metaphosphate, and hydrates of these phosphates. Among the borates, sodium tetraborate, sodium metaborate, sodium metaborate, and hydrates of these borates are preferable, and sodium tetraborate decahydrate is particularly preferable.
The water-soluble oxoate is usually used in a ratio of 0.1 to 1,000 parts by mass, preferably 1 to 100 parts by mass with respect to 100 parts by mass of the poorly water-soluble inorganic compound.

The polymerization temperature when the suspension is subjected to the polymerization reaction is not particularly limited, but is preferably 50 ° C. or higher, and more preferably 60 to 95 ° C. The time of the polymerization reaction is preferably 1 hour to 20 hours, more preferably 2 hours to 15 hours.

The colored resin particles obtained by subjecting the suspension to a polymerization reaction may be used as a polymerization toner by adding an external additive as they are, but these colored resin particles are used as a core layer, and a shell different from the core layer is provided on the outside thereof. It is preferable to use so-called core-shell type (or "capsule type") colored resin particles obtained by forming a layer. The core-shell type colored resin particles balance the lowering of the fixing temperature and the prevention of aggregation during storage by coating the core layer made of a substance having a low softening point with a substance having a higher softening point. be able to.

The method for producing the core-shell type colored resin particles using the colored resin particles obtained by subjecting the suspension to a polymerization reaction is not particularly limited, and can be produced by a conventionally known method. The in situ polymerization method and the phase separation method are preferable from the viewpoint of production efficiency.

A method for producing core-shell type colored resin particles by the in situ polymerization method will be described below.
A polymerizable monomer (polymerizable monomer for shell) and a polymerization initiator for forming a shell layer are added to a dispersion liquid in which colored resin particles obtained by subjecting the suspension to a polymerization reaction are dispersed. By polymerization, core-shell type colored resin particles can be obtained.

As the polymerizable monomer for the shell, the same one as the above-mentioned polymerizable monomer can be used. Among them, it is preferable to use monomers such as styrene, acrylonitrile, and methyl methacrylate that can obtain a polymer having a Tg of more than 80 ° C. alone or in combination of two or more.

Examples of the polymerization initiator used for the polymerization of the polymerizable monomer for shells include metal persulfates such as potassium persulfate and ammonium persulfate; 2,2'-azobis (2-methyl-N- (2-hydroxyethyl)). ) Propionamide), and azo initiators such as 2,2'-azobis- (2-methyl-N- (1,1-bis (hydroxymethyl) 2-hydroxyethyl) propionamide); etc. A polymerization initiator can be mentioned. These can be used alone or in combination of two or more. The amount of the polymerization initiator is preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer for shells.

The polymerization temperature of the shell layer is preferably 50 ° C. or higher, more preferably 60 to 95 ° C. The time of the polymerization reaction is preferably 1 to 20 hours, more preferably 2 to 15 hours.

(4) Washing, Filtration, Dehydration, and Drying Steps In the production method of the present disclosure, the aqueous dispersion of colored resin particles obtained by the polymerization step is washed, filtered, dehydrated, and dried according to a conventional method. It is preferable to further have a step of repeating the process several times as needed.

The washing is performed to remove the poorly water-soluble inorganic compound used as the dispersion stabilizer from the aqueous dispersion of the colored resin particles obtained by the polymerization step. Examples of the cleaning method include a method of dissolving a poorly water-soluble inorganic compound in water and removing it by adding an acid or an alkali to an aqueous dispersion of colored resin particles. Above all, it is preferable to add an acid to adjust the pH of the aqueous dispersion of the colored resin particles to 6.5 or less. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and organic acids such as formic acid and acetic acid can be used, but in particular, because the removal efficiency is high and the burden on the manufacturing equipment is small. Sulfuric acid is suitable.

Various known methods and the like can be used for dehydration and filtration, and the method is not particularly limited. For example, a centrifugal filtration method, a vacuum filtration method, a pressure filtration method and the like can be mentioned. Further, the drying method is not particularly limited, and various methods can be used.

The colored resin particles obtained through the above steps have a volume average particle size (Dv) of preferably 3 to 15 μm, more preferably 4 to 12 μm. When Dv is at least the above lower limit value, the fluidity of the toner can be improved, and deterioration of transferability and reduction of image density can be suppressed. When Dv is equal to or less than the upper limit value, it is possible to suppress a decrease in the resolution of the formed image.

The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of the colored resin particles is preferably 1.0 to 1.3, and more preferably 1. It is 0 to 1.2. When Dv / Dn is 1.3 or less, deterioration of transferability, image density and resolution can be suppressed. The volume average particle size and the number average particle size of the colored resin particles can be measured using, for example, a particle size analyzer (manufactured by Beckman Coulter, trade name: Multisizer) or the like.

The average circularity of the colored resin particles is preferably 0.96 to 1.00, more preferably 0.97 to 1.00, and 0.98 to 1.00 from the viewpoint of image reproducibility. Is more preferable.
When the average circularity of the colored resin particles is 0.96 or more, the fine line reproducibility of printing can be improved. The average circularity of the colored resin particles of the present disclosure is 1 or less, and when the measurement sample is a perfect sphere, the average circularity is 1.
In the present disclosure, the circularity is a value obtained by dividing the perimeter of a circle having the same projected area as the particle image by the perimeter of the projected image of the particle. The average circularity is an index indicating the degree of unevenness on the surface of the measurement sample, and can be used as a simple method for quantitatively expressing the shape of particles. The more complicated the surface shape of the measurement sample, the smaller the average circularity.
For the circularity of the colored resin particles, for example, an aqueous solution in which the colored resin particles are dispersed is used as a sample solution, and a flow-type particle image analyzer (for example, manufactured by Simex, trade name: FPIA-3000, etc.) is used in the sample solution. The projected image of the colored resin particles of the above is taken, and the peripheral length of the circle equal to the projected area of the particles and the peripheral length of the particle projected image are measured from the projected image. It can be obtained by (peripheral length of a circle equal to the projected area) / (peripheral length of a particle projection image). The average circularity is the average value of the circularity of each colored resin particle contained in the sample liquid.

(5) External Addition Step The colored resin particles obtained through the above steps can be used as toner as they are, but from the viewpoint of adjusting the chargeability, fluidity, storage stability, etc. of the toner, the colored resin particles are used. By mixing and stirring together with the external additive and performing the external addition treatment, the external additive may be adhered to the surface of the colored resin particles to obtain a one-component toner.
The one-component toner may be further mixed and stirred together with the carrier particles to prepare a two-component developer.

The stirrer for performing the external addition treatment is not particularly limited as long as it is a stirrer capable of adhering the external additive to the surface of the colored resin particles. Mixer (: product name, manufactured by Kawada Seisakusho), Q mixer (: product name, manufactured by Nippon Coke Industries, Ltd.), Mechanofusion system (: product name, manufactured by Hosokawa Micron), and Mechanomill (: product name, manufactured by Okada Seiko Co., Ltd.) ) Etc., the external addition treatment can be performed using a stirrer capable of mixing and stirring.

Examples of the external additive include inorganic fine particles such as silica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, calcium phosphate and cerium oxide; organic fine particles such as polymethyl methacrylate resin, silicone resin and melamine resin; etc. Can be mentioned. Among these, inorganic fine particles are preferable, and among the inorganic fine particles, at least one kind of fine particles selected from silica and titanium oxide is preferable, and silica fine particles are particularly preferable.
Although each of these external additives can be used alone, it is preferable to use two or more of them in combination.

In the present disclosure, the external additive is usually used in a proportion of 0.05 to 6 parts by mass, preferably 0.2 to 5 parts by mass, based on 100 parts by mass of the colored resin particles. When the amount of the external additive added is not less than the lower limit value, the generation of transfer residue can be suppressed, and when it is not more than the upper limit value, fog can be suppressed.

2. Toner for static charge image development The toner for static charge image development obtained by the production method of the present disclosure has a blocking generation temperature (heat resistant temperature) of preferably 55 ° C. or higher, more preferably 56 ° C. or higher, still more preferably 57 ° C. or higher. Even more preferably, it is 59 ° C. or higher.
In the present disclosure, the toner blocking generation temperature is the maximum temperature at which the mass of the agglomerated toner is 5% by mass or less of the total amount of the toner when the toner is stored at a constant temperature for 8 hours, and in the examples described later. It can be obtained by the same method as the method for obtaining the heat resistant temperature of toner.

The toner for static charge image development obtained by the production method of the present disclosure has a fixing temperature of preferably 130 ° C. or lower, more preferably 125 ° C. or lower, still more preferably 120 ° C. or lower.
The fixing temperature of the toner can be obtained by the same method as the method of obtaining the minimum fixing temperature of the toner in the examples described later.

The toner for static charge image development obtained by the production method of the present disclosure is left at room temperature and normal humidity (N / N) environment at a temperature of 23 ° C. and a humidity of 50% for 24 hours at a temperature of 23 ° C. and a humidity of 50%. When the print durability test is performed in an N / N environment, the image density of the solid black image is 1.30 or more and the fog value is 3 or less even when 20,000 sheets are continuously printed. It is preferable to be able to do it.
Further, the toner for static charge image development obtained by the manufacturing method of the present disclosure is stored for one month in a high temperature and high humidity environment at a temperature of 50 ° C. and a humidity of 80%, and then further at a high temperature of 32.5 ° C. and a humidity of 80%. After being left in a high humidity (H / H) environment for 24 hours and performing a printing durability test in an H / H environment at the temperature of 32.5 ° C. and a humidity of 80%, 20,000 sheets were continuously printed. Even at the time point, it is preferable that the image density of the solid black image is 1.30 or more and the image quality with the fog value of 3 or less can be maintained.
The print durability test is performed by the same method as the print durability test in the examples described later. The fog value is obtained in the same manner as the fog value in the examples described later.

The toner for static charge image development obtained by the production method of the present disclosure has a release agent bleeding rate of preferably 10% or less after being stored for one month in a high temperature and high humidity environment at a temperature of 50 ° C. and a humidity of 80%. It is preferably 7% or less, more preferably 5% or less, and even more preferably 1.5% or less.
The toner release agent bleed rate can be obtained by the same method as the method for obtaining the toner release agent bleed rate in Examples described later.

In the static charge image developing toner obtained by the production method of the present disclosure, the conductivity (electrical conductivity) of the filtrate obtained by reslurrying the toner and filtering it is preferably 300 μS / cm or less, more preferably 250 μS. It is less than / cm. The conductivity of the filtrate is an index of the residual amount of the metal compound derived from the poorly water-soluble inorganic compound on the toner surface. When the conductivity of the filtrate is not more than the upper limit, the residual amount of metal compounds on the toner surface is sufficiently reduced, so that the printing durability when the toner is stored for a long time in a high temperature and high humidity environment. Deterioration can be suppressed. The lower limit of the conductivity of the filtrate is not particularly limited, and is usually 100 μS / cm or more.
The toner is reslurried by dispersing the toner in ion-exchanged water in which a nonionic surfactant is dissolved.

Hereinafter, the present disclosure will be described in more detail with reference to Examples and Comparative Examples, but the present disclosure is not limited to these Examples. Parts and% are based on mass unless otherwise specified.
The weight average molecular weight Mw of the polymer was determined in terms of polystyrene by GPC. The sample for measurement was prepared by dissolving the polymer in tetrahydrofuran (THF) so as to have a concentration of 2 mg / mL, performing ultrasonic treatment for 10 minutes, and then passing through a 0.45 μm membrane filter. The measurement conditions were temperature: 40 ° C., solvent: tetrahydrofuran, flow velocity: 1.0 mL / min, concentration: 0.2 wt%, sample injection amount: 100 μL, and the column was GPC TSKgel Multipore HXL-M (manufactured by Tosoh Corporation). 30 cm x 2) was used. Further, the measurement was performed under the condition that the first-order correlation equation of Log (Mw) -elution time between weight average molecular weight Mw 1,000 and 300,000 was 0.98 or more.

[Production Example 1: Production of Copolymer 1]
200 parts of toluene was put into the reaction vessel, the inside of the reaction vessel was sufficiently replaced with nitrogen while stirring the toluene, and then the temperature was raised to 90 ° C. After that, 96.2 parts of methyl methacrylate, 3.5 parts of ethyl acrylate, 0.4 parts of acrylic acid, and t-butylperoxy-2-ethylhexanoate (manufactured by Nippon Oil & Fats Co., Ltd., trade name: Perbutyl O) 2. Eight parts of the mixed solution was added dropwise into the reaction vessel over 2 hours. Further, the polymerization was completed by holding the mixture under reflux with toluene for 10 hours, and then the solvent was distilled off under reduced pressure. In this way, copolymer 1 (Tg77.8 ° C., acid value 2.4 mgKOH / g, weight average molecular weight Mw12500) was obtained.

[Production Examples 2-4: Production of Copolymers 2-4]
Copolymers 2 to 4 were obtained in the same manner as in Production Example 1 except that the type and amount of the monomer added were changed as shown in Table 1.

The abbreviations in Table 1 are as follows.
AA: Acrylic acid MMA: Methyl methacrylate EA: Ethyl acrylate BA: n-Butyl acrylate

[Example 1]
1. 1. Production of Colored Resin Particles (1) Preparation of Polymerizable Monomer Composition for Core 77 parts of styrene and 23 parts of n-butyl acrylate as monovinyl monomer, carbon black as colorant (manufactured by Mitsubishi Chemical Corporation, trade name: # 25B) 7 parts, divinylbenzene 0.6 parts as a crosslinkable polymerizable monomer, t-dodecyl mercaptan 1.2 parts as a molecular weight modifier, polymethacrylic acid ester macromonomer as a macromonomer (manufactured by Toa Synthetic Chemical Industry Co., Ltd.) , Trade name: AA6, Tg = 94 ° C.) 0.3 parts, and 1.0 part of polar resin (monomer 1 obtained in Production Example 1) were wet-ground using a media-type wet crusher. Obtained a mixture. In this mixture, 1 part of a charge control resin as a charge control agent (styrene acrylic resin containing a quaternary ammonium salt as a functional group, copolymerization ratio of a monomer containing a functional group of a quaternary ammonium salt: 2% by mass), As a release agent, 20 parts of behenyl stearate (number average molecular weight Mn: 592) was added and mixed to obtain a polymerizable monomer composition for a core.

(2) Preparation of aqueous medium On the other hand, in an aqueous solution in a stirring tank in which 7.4 parts of magnesium chloride (water-soluble polyvalent metal salt) is dissolved in 250 parts of ion-exchanged water at room temperature, 50 parts of ion-exchanged water is added to water. An aqueous solution in which 4.1 parts of sodium oxide (alkali metal hydroxide) was dissolved was gradually added under stirring to prepare a magnesium hydroxide colloid (water-insoluble inorganic hydroxide colloid) dispersion.

(3) Preparation of Polymerizable Monomer for Shell On the other hand, 2 parts of methyl methacrylate and 65 parts of ion-exchanged water are finely dispersed by an ultrasonic emulsifier to prepare an aqueous dispersion of the polymerizable monomer for shell. Prepared.

(4) Preparation of Suspension The above-mentioned polymerizable monomer composition for core was added to the above-mentioned magnesium hydroxide colloidal dispersion and stirred, and t-butylperoxyisobutyrate (Japan) was used as a polymerization initiator therein. 6 parts of Perbutyl IB) manufactured by Yusha Co., Ltd. was added. After that, using an in-line emulsion disperser (manufactured by Pacific Machinery & Engineering Co., Ltd., trade name: Milder), the peripheral speed of the rotor was set to 23.6 m / s and the rotation speed was set to 15,000 rpm. By carrying out the dispersion treatment while circulating until the number of circulations of the dispersion liquid calculated by the above was 10, a suspension in which droplets of the polymerizable monomer composition for core were dispersed in an aqueous medium was prepared.

(5) Formation of Colored Resin Particles 1 part of sodium tetraborate decahydrate was added to the suspension prepared above. The suspension to which sodium tetraborate decahydrate was added was placed in a reactor equipped with a stirring blade, and the temperature was raised to 85 ° C. to carry out a polymerization reaction. After the polymerization conversion rate reached almost 100%, the aqueous dispersion of the polymerizable monomer for shells prepared above and 2,2'-azobis (2-methyl-N- (2-methyl-N- (2-methyl-N-) as the polymerization initiator for shells. 2-Hydroxyethyl) -propionamide) (manufactured by Wako Pure Chemical Industries, Ltd., trade name: VA-086, water-soluble) 0.3 part was added to the reactor. Further, after continuing the polymerization for 4 hours, the reaction was stopped by water cooling to obtain an aqueous dispersion of colored resin particles having a core-shell structure.

(6) Post-treatment step The aqueous dispersion of the colored resin particles was washed with dilute sulfuric acid (25 ° C. for 10 minutes) to bring the pH to 4.5 or less. Then, after separating the water by filtration, 200 parts of ion-exchanged water was newly added to reslurry, and washing, filtration, and dehydration were repeated several times at room temperature (25 ° C.) for water washing treatment. The obtained solid content was separated by filtration and then vacuum dried to obtain dried colored resin particles.

2. Manufacture of Toner 100 parts of the colored resin particles obtained above are hydrophobized with 0.5 parts of silica fine particles having an average primary particle size of 7 nm, which is hydrophobized with cyclic silazane as an external additive, and amino-modified silicone oil. A part of silica fine particles having an average primary particle size of 35 nm was added, and the mixture was mixed and stirred using a high-speed stirrer (manufactured by Nippon Coke Industries, Ltd., trade name: FM mixer) to perform an external addition treatment. The static charge image developing toner of Example 1 was prepared.

[Examples 2 to 10 and 12 and Comparative Examples 1 to 6]
In Example 1, the type and amount of the polar resin added to the polymerizable monomer composition for the core when producing the colored resin particles were changed according to Table 2, and the rotor was used when preparing the suspension. Toners for developing electrostatic charge images of Examples 2 to 10 and 12 and Comparative Examples 1 to 6 in the same manner as in Example 1 except that the peripheral speed and the number of rotations of the dispersion liquid and the number of circulations of the dispersion liquid were changed according to Table 2. Was produced.

[Example 11]
In Example 1, when preparing the suspension, a horizontal emulsifying disperser (manufactured by Eurotech, trade name: Cavitron) was used instead of the milder as a stirrer, and the peripheral speed of the rotor was 40 m / s. In the same manner as in Example 1, the static treatment of Example 11 was carried out, except that the dispersion treatment was performed while circulating until the number of circulations of the dispersion liquid calculated by the above formula (I) reached 16 at a rotation speed of 15600 rpm. A toner for charge image development was prepared.

[evaluation]
The toner for static charge image development obtained in each Example and each Comparative Example and the colored resin particles used in the production of the toner were evaluated.

(1) Volume average particle size (Dv), number average particle size (Dn), and particle size distribution (Dv / Dn) of colored resin particles
Approximately 0.1 g of the colored resin particles were weighed, placed in a beaker, and 0.1 mL of an aqueous surfactant solution (manufactured by Fujifilm, trade name: Drywell) was added as a dispersant. Add 10 to 30 mL of Isoton II to the beaker, disperse it with a 20 W ultrasonic disperser for 3 minutes, and then use a particle size measuring machine (Beckman Coulter, trade name: Multisizer) to measure the aperture diameter. The volume average particle size (Dv) and the number average particle size (Dn) of the colored resin particles were measured under the conditions of 100 μm, medium; Isoton II, number of particles to be measured; 100,000 particles, and the particle size distribution (Dv) was measured. / Dn) was calculated.

(2) Toner Release Agent Bleed Rate First, as the toner after storage, a toner after being stored for one month in a high temperature and high humidity environment at a temperature of 50 ° C. and a humidity of 80% was prepared.
After storing the stored toner on a carbon tape and removing excess toner with a blower, SEM observation is performed at a magnification of 2,000 times, and the total number of toner particles (A) in one image is 500 to 700. Ten images were taken so as to be. For each of the obtained toner images, the release agent bleed rate was calculated by the following formula (i) from the total number of toner particles (A) and the number of toner particles (B) from which the release agent bleeds out. The average value of the calculated 10 values was used as the release agent bleed rate of the toner.
Equation (i)
Release agent bleed rate (%) = (Number of toner particles bleeded out by the release agent (B) / Total number of toner particles (A)) x 100
The toner from which the release agent has bleeded out can be identified from the fact that flakes having a size of 0.5 to 3 μm are observed on the surface of the toner.

(3) Toner printing durability (3) -1. Printing Durability in N / N Environment After leaving the toner before storage in a room temperature normal humidity (N / N) environment with a temperature of 23 ° C and a humidity of 50% for 24 hours, the toner of the developing device under the same environment. A printing durability test was conducted in which a cartridge was filled, printing paper was set, and continuous printing was performed up to 20,000 sheets at a printing density of 5%. A commercially available non-magnetic one-component developing printer (printing speed: A4 size 40 sheets / minute) was used for the printing durability test. During the print durability test, solid black printing (print density 100%) is performed every 500 sheets, and the image density of the solid black image is measured using a reflective image densitometer (manufactured by Macbeth, trade name: RD918). After that, solid white printing (printing density 0%) was performed. The printer was stopped in the middle of solid white printing, and the toner in the non-image area on the developed photoconductor was attached to an adhesive tape (manufactured by Sumitomo 3M Ltd., trade name: Scotch Mending Tape 810-3-18). After that, it was peeled off and pasted on printing paper. Next, the whiteness (B) of the printing paper to which the adhesive tape was attached was measured with a whiteness meter (manufactured by Nippon Denshoku Co., Ltd., trade name: ND-1). The whiteness (A) was measured, and the difference in whiteness (BA) was used as the fog value. The smaller the fog value, the less fog and the better. The number of continuous prints capable of maintaining an image quality of a solid black image having an image density of 1.30 or more and a fog value of 3 or less was investigated. Table 2 shows the results of the printing durability test of the toner before storage under a normal temperature and humidity (N / N) environment at a temperature of 23 ° C. and a humidity of 50% as N / N durability.

(3) -2. Printing durability in an H / H environment after storage in a high-temperature and high-humidity environment As a toner after storage, a toner after storage in a high-temperature and high-humidity environment with a temperature of 50 ° C. and a humidity of 80% for one month was prepared.
After storage, the toner was left for 24 hours in a high temperature and high humidity (H / H) environment with a temperature of 32.5 ° C. and a humidity of 80%, and then the same printing durability test as above was performed in the same environment to obtain black. The number of continuous prints capable of maintaining an image quality of a solid image having an image density of 1.30 or more and a fog value of 3 or less was investigated. H / H / Table 2 shows the H durability.
In Table 2 below, ">20000" means that the image quality with an image density of 1.30 or more and a fog value of 3 or less could be maintained even at the time of 20,000 images. ..

(4) Minimum fixing temperature of toner A fixing test was conducted using a printer modified so that the temperature of the fixing roll portion of a commercially available non-magnetic one-component developing printer could be changed.
In the fixing test, solid black printing (printing density 100%) is performed, the temperature of the fixing roll of the modified printer is changed by 5 ° C, and the fixing rate of the toner at each temperature is measured. I went for a relationship.
The fixing rate was calculated from the ratio of the image density before and after the tape peeling after the tape was peeled off in the black solid (print density 100%) print area. That is, assuming that the image density before the tape peeling is ID (front) and the image density after the tape peeling is ID (rear), the fixing rate can be calculated by the following formula (ii).
Equation (ii)
Retention rate (%) = (ID (rear) / ID (front)) x 100
Here, the tape peeling operation is to attach an adhesive tape (manufactured by Sumitomo 3M Ltd., trade name: Scotch Mending Tape 810-3-18) to the measurement part of the test paper, press it with a constant pressure to attach it, and then attach it. It is a series of operations to peel off the adhesive tape in the direction along the paper at a constant speed. The image density was measured using a reflection type image densitometer (manufactured by Macbeth, trade name: RD914).
In this fixing test, the temperature of the lowest fixing roll having a fixing rate of more than 80% was defined as the minimum fixing temperature of the toner.

(5) Preservation of Toner 10 g of toner was placed in a 100 mL polyethylene container and sealed, and then the container was submerged in a constant temperature water tank set at a predetermined temperature and taken out after 8 hours. Toner was transferred from the removed container onto a 42-mesh sieve with as little vibration as possible, and set in a powder measuring machine (manufactured by Hosokawa Micron, trade name: Powder Tester PT-R). The amplitude of the sieve was set to 1.0 mm, the sieve was vibrated for 30 seconds, and then the mass of the toner remaining on the sieve was measured and used as the mass of the aggregated toner.
The maximum temperature (° C.) at which the mass of the aggregated toner is 0.5 g or less was defined as the heat resistant temperature of the toner, and was used as an index of the heat resistant storage stability of the toner.

(6) Toner resurrection filtrate Conductivity 10 g of toner is placed in 40 g of ion-exchanged water (conductivity <10 μS / cm) in which 1% nonionic surfactant is dissolved, and the mixture is stirred with a magnetic stirrer for 1 hour to disperse. The toner was made into a reslurry. Then, the filtrate was collected by suction filtration, and the conductivity of the filtrate was measured with an electric conductivity meter. The higher the conductivity of the filtrate, the more the metal compound remains on the toner surface.

[Discussion]
The toners obtained in Comparative Examples 1 and 2 are inferior in printing durability because the number of circulations of the dispersion liquid is less than 10 in the step of preparing the suspension, and particularly in a high temperature and high humidity environment for one month. The printing durability after storage was inferior.
The toner obtained in Comparative Example 3 was inferior in printing durability because the peripheral speed of the rotor of the disperser was less than 15 m / s in the step of preparing the suspension, especially in a high temperature and high humidity environment. The printing durability was inferior after being stored for 1 month.
In Comparative Examples 1 to 3, the conductivity of the filtrate obtained by reslurrying the obtained toner was high. This indicates that the metal compound derived from the poorly water-soluble inorganic compound remains on the toner surface. From the results of Comparative Examples 1 to 3, it can be inferred that the deterioration of printing durability after long-term storage in a high temperature and high humidity environment is partly due to the metal compound remaining on the toner surface. .. In Comparative Examples 1 to 3, the suspension was prepared by a poorly water-soluble inorganic compound due to insufficient circulation of the dispersion liquid or insufficient peripheral speed of the rotor. It is presumed that the effect as a dispersion stabilizer was not sufficiently exhibited, and as a result of the droplets of the polymerizable monomer composition being aggregated, the metal compound remained on the toner surface.
The toner obtained in Comparative Example 4 had a high minimum fixing temperature and was inferior in low-temperature fixability because the content of the polar resin exceeded 2.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer. rice field.
Since the content of the polar resin in the toner obtained in Comparative Example 5 was less than 0.8 parts by mass with respect to 100 parts by mass of the polymerizable monomer, it was stored for one month in a high temperature and high humidity environment. The release agent bleed rate was high and the printing durability was inferior, and the printing durability was inferior after being stored for one month in a high temperature and high humidity environment.
Since the toner obtained in Comparative Example 6 did not contain a polar resin, the release agent bleeding rate after storage in a high temperature and high humidity environment for one month was high, and the printing durability was inferior, particularly high temperature and high humidity. The printing durability after being stored in the environment for one month was inferior, the heat resistant temperature was low, and the heat resistant storage stability of the toner was also inferior.

On the other hand, the toners obtained in Examples 1 to 12 have a polar resin content of 0.8 to 2.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer, and can be used as a suspension. In the preparation process, the peripheral speed of the rotor of the disperser was 15 to 40 m / s, and the number of circulations of the dispersion was 10 to 30, so that the heat resistant temperature was high and the minimum fixing temperature was low. It has an excellent balance between heat-resistant storage and low-temperature fixability, and even after being stored for one month in a high-temperature and high-humidity environment with a temperature of 50 ° C and a humidity of 80%, it has excellent printing durability and bleeding of a mold release agent. Was suppressed. Further, in Examples 1 to 12, the conductivity of the filtrate obtained by resallying the obtained toner was low, and the metal compound derived from the poorly water-soluble inorganic compound was sufficiently removed from the toner.

1 Dispersion liquid supply tank 2 Disperser 3 Casing 4 Rotor 5 Stator 6 Rotating shaft 7 Dispersion liquid supply line 8 Circulation line 9 Supply line to polymerization reactor 10 Stirrer

Claims (5)

Prepare a suspension in which droplets of a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, a polar resin and a mold release agent are dispersed in an aqueous medium containing a poorly water-soluble inorganic compound. And the process to do
A method for producing a toner for developing an electrostatic charge image, which comprises a step of forming colored resin particles by subjecting the suspension to a polymerization reaction.
The content of the polar resin is 0.8 to 2.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
In the step of preparing the suspension,
A disperser having a combination of a rotor and a stator, which are comb-tooth type concentric rings, and a stirrer having a dispersion liquid supply tank are used.
The dispersion liquid containing the aqueous medium and the polymerizable monomer composition is supplied from the dispersion liquid supply tank to the disperser, stirred by the disperser, and then discharged to the dispersion liquid supply tank. The suspension is prepared by repeatedly circulating in the stirrer.
The peripheral speed of the rotor of the disperser is 15 to 40 m / s.
A method for producing a toner for static charge image development, wherein the number of circulations of the dispersion liquid calculated by the following formula is 10 to 30.
Number of times the dispersion liquid is circulated = {Flow rate of the dispersion liquid (liter / h) x Treatment time (h)} / Amount of dispersion liquid charged (liter) The polar resin is a copolymer of at least one selected from acrylic acid ester and methacrylic acid ester and at least one selected from acrylic acid and methacrylic acid, and has an acid value of 0.5 to 7.0 mgKOH /. The method for producing an electrostatic charge image developing toner according to claim 1, wherein the amount is g, the weight average molecular weight Mw is 8,000 to 45,000, and the glass transition temperature is 60 to 95 ° C. The method for producing a toner for static charge image development according to claim 1 or 2, wherein the poorly water-soluble inorganic compound is an inorganic hydroxide. The method for producing a toner for static charge image development according to any one of claims 1 to 3, wherein the poorly water-soluble inorganic compound is magnesium hydroxide. The method for producing a toner for static charge image development according to any one of claims 1 to 4, wherein the release agent is a monoester compound.

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