JP3256828B2 - Yellow toner for developing positive charge images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for developing an electrostatic image which develops an electrostatic image formed in an electrophotographic method, an electrostatic printing method or the like.

More specifically, the present invention relates to a yellow toner obtained by subjecting a monomer composition containing at least a release agent and a colorant to aqueous suspension polymerization.

[0003]

2. Description of the Related Art Conventionally, a developer using an electrophotographic process is prepared by adding a colorant, a charge control agent and a mold release agent to a polyester / styrene-acryl / epoxy resin or the like, melt-kneading them, and dispersing them uniformly. A production method based on a pulverization method in which pulverization is performed to a predetermined particle size and excess fine / coarse powder developer is removed using a classifier is general.

However, with the recent trend toward higher image quality, it has become necessary to further reduce the particle size of the developer.

However, as the particle size measured by the Coulter counter becomes 9 μm or less, the developer is classified into a uniform dispersion of the raw materials used, a highly efficient grindability, and a sharp particle size distribution, which have not been a problem in the past. Tends to be extremely difficult.

In order to overcome the problems of the developer by these pulverization methods, Japanese Patent Publication No. 36-10231 and Japanese Patent Publication No. 43-1
No. 0799 and Japanese Patent Publication No. 51-14895 propose a method for producing a developer by a suspension polymerization method.
In the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer composition. Thereafter, the monomer composition is dispersed in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase using a suitable stirrer, and simultaneously undergoes a polymerization reaction to obtain a developer having a desired particle size. Is the way.

This manufacturing method does not require a pulverizing step, so that it is not necessary to impart brittleness to the developer, and a large amount of a low softening point substance which cannot be used in the conventional pulverizing method can be used. The range of choice of materials such as is widened. In addition, the release agent and the colorant, which are hydrophobic materials, are difficult to be exposed on the surface of the developer particles, so that the developer holding member, the photoconductor,
It has attracted attention recently because of its features such as less contamination of the transfer roller and the fixing device.

In recent years, digital full-color copiers and printers have been put to practical use, and toner has high image fidelity,
It has become necessary to further improve special features such as releasability and color reproducibility.

As the required quality required for image fidelity,
Digital full-color copiers require a greater amount of developer to be transferred from the photoconductor to the transfer material than black-and-white copiers, and require a developer that can handle finer dots to support higher image quality in the future. A demand for finer particle size is expected.

From this point of view, the polymerization method capable of relatively easily producing a developer having a sharp particle size distribution and a fine particle size has excellent characteristics.

As the speed and full color of printers and copiers increase in the future, improvement of low-temperature fixability is also an important factor.

In a full-color copying machine, it is essential that a multicolor toner is sufficiently mixed in a fixing step to obtain color reproducibility and transparency of an OHP image.
Generally, a low-molecular weight resin having a sharp melt is demanded.

In general, a black toner is made of a crystalline material having relatively high releasability, such as polyethylene wax or polypropylene wax, in order to improve high-temperature offset resistance during fixing. When the above wax is used, the transparency is significantly impaired when output to OHP due to the high crystallinity of the release agent.

For this reason, by applying a silicone oil or the like to the heat fixing roller uniformly without adding a release agent as a component of the color toner, the high-temperature offset resistance is improved as a result. However, the output transfer member obtained in this manner is not preferable because extra silicone oil or the like adheres to the surface thereof, which causes discomfort when used by a user.

For this reason, an oil-less fixing developer containing a large amount of a low softening point substance in a developer has been studied. However, the developer has excellent low-temperature fixing property and transparency, and at the same time, has high-temperature offset resistance. No satisfactory developer has been obtained yet.

In addition, it becomes more difficult to uniformly include a release agent in a pulverization method as the toner has a fine particle diameter, so that the inclusion of a release agent having a small particle diameter has become a major problem.

The required quality required for special colors such as color reproducibility includes further improvements in color tone, saturation, coloring power, and the like, and most of them are affected by modification of the coloring agent itself.

In particular, yellow toner is in great demand as a color used for skin color and the like, and many pigments such as mono / disazo-based, anthraquinone-based, quinoline-based, isoindolinone-based, pyridone-based and methine-based pigments have been used. It has been disclosed as a dye for use.

For example, Japanese Patent Application Laid-Open No. 62-54275 discloses a disazo pigment, and Japanese Patent Application Laid-Open No. 1-227162.
Japanese Patent Application Laid-Open No. 4-1992 discloses an anthraquinone pigment.
JP-A-241363 describes a methine dye and JP-A-5-19535 describes an isoindolinone pigment.

Among these colorants, pigments have good melt affinity to a binder resin and good light fastness even in an aqueous polymerized toner, and a toner excellent in charging characteristics and color tone is obtained.
However, in order to obtain an image more faithful to the original while satisfying the low-temperature fixability and transparency, it is necessary to further improve image durability / environmental stability, affinity with the release agent, color tone, saturation, etc. Improvement is desired.

Conventionally, from these viewpoints and productivity / cost, Pig. Y. Disazo pigments represented by 17/93/97 and the like have been used, but when these colorants are polymerized directly in an aqueous medium, polymerization inhibition occurs.
It has been found that a phenomenon (hereinafter, referred to as a persimmon seed) that a solid image is partially whitened out due to toner fusion to a developer carrying member and coarse particles being formed in a color image marking test or the like.

[0022]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color toner for developing an electrostatic image, which has solved the above-mentioned disadvantages.

That is, an object of the present invention is to provide a color toner for developing an electrostatic image having excellent OHP transparency and charging characteristics having excellent environmental stability.

Another object of the present invention is to provide a color toner for developing an electrostatic image having excellent heat and light resistance.

A further object of the present invention is to provide a color toner for developing an electrostatic image, which can obtain a very clear color.

[0026]

The purpose of the object of resolving means and the action for the present invention is obtained by polymerizing directly aqueous medium of the monomer composition containing at least a polymerizable monomer, a wax and a colorant
In a yellow toner, the toner has a weight average diameter of 9
and a μm or less, the wax has an ester wax, and the colorant is by <br/> a yellow toner for developing an electrostatic image, comprising a skeleton represented by the following structural formula Achieved.

[0027]

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[Wherein X _{1 to} X ₄ are a methyl group, an ethyl group,
An alkyl group such as an (iso) propyl group, a halogen group such as a fluorine atom, a chlorine atom and an iodine atom, or a hydrogen atom;
X _{1 to} X ₄ may be the same or different. ]

Hereinafter, the present invention will be described in detail.

The present invention achieves the object of the present invention by combining the pigment of the present invention with a specific wax.

This is because the ester group in the wax has an affinity for the functional group of the pigment having the structure of the present invention, so that the pigment is taken into the hydrophobic wax and buried in the toner. I think it will happen.

As X _{1 to} X ₄ in the general formula (1), it is necessary to select an appropriate one for reasons such as the color of the colorant.
In the present invention, an alkyl group such as a methyl group, an ethyl group, an (iso) propyl group, a butyl group, an isobutyl group, a t-butyl group and a substituent derivative thereof; a methoxy group, an ethoxy group, an n-propoxy group, and an n- A substituent having an oxygen functional group such as an alkoxy group such as a butoxy group, a t-butoxy group, or an n-hexyloxy group; a halogen atom such as a fluorine atom, a chlorine atom, or an iodine atom; or a hydrogen atom. .

From the viewpoint of hue and transparency, the pigment of the present invention is preferably contained in the toner in an amount of 0.2 to 15% by weight.

The pigment of the present invention can be combined with other conventionally known coloring agents for improving the color tone, but the effect of inhibiting the transfer of the aqueous phase by the ester wax tends to be greatly inhibited by the other coloring agents. Therefore, the pigment 100 of the present invention
Preferably it is less than 20 parts by weight per part by weight.

In the present invention, an improvement in chargeability is achieved by combining a wax having an ester group with the pigment of the present invention.

From the viewpoint, the wax of the present invention more preferably has one or more long-chain ester moieties having 15 or more carbon atoms, and more preferably 15 or more and 30 or less.

When the number of carbon atoms is less than 15, although the surface of the pigment is modified, the water phase migration property of the pigment cannot be suppressed, and the charging stability of the toner deteriorates. If the number of carbon atoms exceeds 30, the plasticizing effect of the wax on the resin becomes too large, and the fixability decreases.

In recent years, the necessity of full-color double-sided images has been increasing. When forming a double-sided image, the toner image formed on the transfer paper first formed on the front surface is also used for forming the image next on the rear surface. There is a possibility that the toner may pass through the heating unit of the fixing device again, and it is necessary to sufficiently consider the high-temperature offset resistance of the toner. Therefore, in the present invention, it is essential to add a large amount of ester wax.

For this reason, the ester wax of the present invention needs to impart releasability and transparency in addition to modifying the pigment, and it is preferable to add 5 to 30% by weight of the ester wax to the toner.

If the addition is less than 5% by weight, sufficient reforming property is not exhibited, and the image on the back side tends to show an offset phenomenon when a double-sided image is fixed. If it exceeds 30% by weight, device fusion or toner fusion is likely to occur during the production of the toner, for example, in production by a pulverization method.
Also in the production by the polymerization method, coalescence of the toner particles is likely to occur during granulation, and the impact resistance to the drum is reduced, so that filming is likely to occur.

As a means for adding and modifying an ester wax to the pigment of the present invention, known means such as preparation of a masterbatch in advance can be used. In order to obtain the effect of the above, at the time of adding both, the ester wax 10 was added to 100 parts by weight of the pigment.
It is desirable to add at a ratio of 0 to 3000 parts by weight.

In the present invention, as the ester wax to be used, a compound having a main maximum peak value measured at 40 to 90 ° C. according to ASTM D3418-8 is preferable. If the maximum peak is less than 40 ° C., the self-cohesive force of the low softening point substance becomes weak, and as a result, the hot offset resistance becomes weak, which is not preferable for a full color toner. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature becomes high, and it becomes difficult to appropriately smooth the surface of the fixed image, which is not preferable from the viewpoint of color mixing. Further, in the case of obtaining a toner by a direct polymerization method, since the temperature of the maximum peak value is high because the granulation and polymerization are performed in an aqueous system, a substance having a low softening point mainly precipitates during the granulation and hinders the suspension system. Not preferred.

In the measurement of the temperature of the maximum peak value of the present invention,
For example, DSC-7 manufactured by PerkinElmer is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. An aluminum pan was used as a sample, an empty pan was set as a control, and the temperature was raised at a rate of 10 ° C / min. Was measured.

The structural formulas of typical compounds of the specific ester waxes preferred in the present invention are shown below as general structural formulas / general structural formulas and general structural formulas.

[0045]

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(A, b: integers from 0 to 4; a + b
= 4 R ₁ , R ₂ : an organic group having an integer of 1 to 40 carbon atoms and a difference in carbon number between R ₁ and R ₂ of 3 or more m, n: an integer of 0 to 25; And n do not become 0 at the same time. )

[0047]

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(A, b: integers from 0 to 4, a + b
= 4, b ≠ 0 R ₁ : organic group having an integer of 1 to 40 carbon atoms m, n: an integer of 0 to 25, and m and n do not become 0 at the same time. )

[0049]

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(A, b: integers from 0 to 3, where 1 ≦ a
+ B ≦ 3 R ₁ , R ₂ : an organic group having an integer of 1 to 40 carbon atoms and a difference of 3 or more carbon atoms between R ₁ and R ₂ R ₃ : a hydrogen atom, an organic compound having 1 or more carbon atoms Base. Where a
When + b = 2, one of R ₃ is an organic group having 1 or more carbon atoms k: an integer from 1 to 3 m, n: an integer from 0 to 25, and m and n are simultaneously 0. It will not be. )

The ester wax preferably used in the present invention preferably has a hardness of 0.5 to 5.0.
The hardness of the ester wax is 20mm in diameter and 5m in thickness
m is a value obtained by measuring a Vickers hardness using a dynamic ultra-fine hardness tester (DUH-200) manufactured by Shimadzu Corporation after preparing a cylindrical sample of m. Measurement condition is 0.5g
10 μm at a load speed of 9.67 mm / sec with a load of
After being displaced, it is held for 15 seconds, and the resulting dent shape is measured to determine Vickers hardness. The hardness of the ester wax preferably used in the present invention shows a value of 0.5 to 5.0. A low softening point substance having a hardness of less than 0.5 has a large dependence on the pressure and process speed of the fixing device, and tends to exhibit insufficient high-temperature offset resistance. Poor stability,
Since the self-cohesive force of the release agent itself is small, the modifying property of the pigment of the present invention tends to be insufficient.

Specific compounds include the following compounds.

[0053]

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Further, in the present invention, it is preferable from the viewpoint of pigment modification that the ester wax is encapsulated in the outer resin layer when the cross section of the toner is observed using a transmission electron microscope (TEM).

Means for encapsulating the ester wax include a method of seed polymerization using suspension polymerized particles as a nucleus as disclosed in JP-A-59-6287, and a method disclosed in JP-A-61-46.
Many methods are disclosed, such as a method of adding a polar resin having poor compatibility with ester wax as disclosed in Japanese Patent Application Laid-Open No. 955, but what methods can be confirmed by the method of the present invention by these known methods. Any suitable means may be used.

The present inventors have found that, among these known methods, the method of adding a polar resin promotes the uneven distribution of the ester wax, and that the method is more effective when combined with any of the known methods. In the present invention, the addition of a polar substance is considered essential.

As the polar resin used in the present invention, generally used materials such as a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin and an epoxy resin are preferably used. .

In the present invention, a specific method for measuring the tomographic plane of the toner is as follows. After the toner is sufficiently dispersed in an epoxy resin which is curable at room temperature, it is cured in an atmosphere at a temperature of 40 ° C. for 2 days. The product is stained with ruthenium tetroxide and, if necessary, osmium tetroxide, and then sliced using a microtome equipped with diamond teeth. The morphology of the toner is measured using a transmission electron microscope (TEM). did. In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to provide a contrast between materials by utilizing a slight difference in crystallinity between the low softening point substance used and the resin constituting the outer shell. FIG. 1 shows a typical example. Obviously, it was observed that the low softening point substance was encapsulated by the outer shell resin.

Further, in the present invention, in order to ensure transferability and developability during high-speed copying, the shape factor SF-1 measured by Luzex preferably ranges from 100 to 130.

In the present invention, SF-1 representing the shape factor is obtained by randomly sampling 100 toner images using an FE-SEM (S-800) manufactured by Hitachi, Ltd. It was introduced into an image analyzer (Luzex3) and analyzed, and the value calculated from the following equation was defined as SF-1 in the present invention.

[Definition formula of SF-1]

[0062]

(Equation 1)

[Wherein, MXLNG indicates the absolute maximum length of the developer on the image, and AREA indicates the projected area of the developer. ]

The developer shape in which the shape factor SF-1 of the developer is larger than 130 gradually changes from a spherical shape to an irregular shape, and at the same time, the transfer efficiency decreases, so that more toner remains without being transferred onto the drum. As a result, filming easily occurs during high-speed copying.

In the case of the toner of the present invention, the shape factor SF-1 of the toner is 100 to 130, more preferably 10 in order to secure practical filming resistance and transfer / developability.
A substantially spherical toner having a particle diameter of 0 to 120 is preferable. In order to faithfully develop finer latent image dots for higher image quality, the particle diameter is smaller than that of the developer, specifically, measured by a Coulter counter. A toner having a weight average diameter of 9 μm or less, more preferably 4 μm to 8 μm, and a number variation coefficient of 35% or less is preferred.

The polymerizable monomers used in the toner of the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene,
Styrene monomers such as p-ethylstyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid 2
Acrylates such as -ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate Octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other methacrylates; and other monomers such as acrylonitrile, methacrylonitrile, and acrylamide Body.

These monomers can be used alone or as a mixture. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with another monomer from the viewpoint of the developing characteristics and durability of the toner.

In order to control the molecular weight,
Known crosslinking agents and chain transfer agents may be added, and the preferable addition amount is 0.001 to 15% by weight.

The polymerization may be carried out by further adding a resin to the monomer system. For example, a monomer contains a hydrophilic functional group such as an amino acid, a carboxylic acid group, a hydroxyl group, a sulfonic acid group, a glycidyl group, or a nitrile group which cannot be used because it dissolves in an aqueous suspension to cause emulsion polymerization due to water solubility. When it is desired to introduce a monomer component into a toner, a random copolymer of these with a vinyl compound such as styrene or ethylene,
It can be used in the form of a copolymer, such as a block copolymer or a graft copolymer, or in the form of a polycondensate such as a polyester or polyamide, or a polyaddition polymer such as a polyether or polyimine.

The amount used is preferably 1 to 20% by weight. The average molecular weight of the high molecular polymer containing these polar functional groups is preferably 5,000 or more.
When the molecular weight is less than 5,000, especially 4,000 or less, the present polymer tends to concentrate near the surface, so that adverse effects on developability, blocking resistance and the like are apt to occur, which is not preferable. Also,
If a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the monomer is dissolved in the monomer and polymerized, a toner having a wide molecular weight distribution and high offset resistance can be obtained.

As the polymerization initiator used in the polymerization method, any suitable polymerization initiator, for example, 2,2
2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,
An azo or diazo polymerization initiator such as 1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile, and benzoyl Examples include peroxide polymerization initiators such as peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, and lauroyl peroxide. These polymerization initiators may be used in an amount of 0.5 to 20 of the polymerizable monomer.
The addition amount of% by weight is preferable, and they may be used alone or in combination.

In the polymerization method, known surfactants and organic / inorganic dispersants can be used as dispersion stabilizers. Among them, inorganic dispersants are unlikely to generate harmful ultrafine powders, and dispersion stability is obtained due to their steric hindrance. Therefore, even if the reaction temperature is changed, the stability is hardly lost, the washing is easy, and the toner is not adversely affected. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate, carbonates such as calcium carbonate and magnesium carbonate, and inorganic salts such as calcium metasilicate, calcium sulfate and barium sulfate. And inorganic oxides such as salts, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite, and alumina.

[0073] These inorganic dispersants are used as polymerizable monomers 10
It is desirable to use 0.2 to 20 parts by weight alone with respect to 0 parts by weight, but 0.001 to 0.1 parts by weight, since it is difficult to generate ultrafine particles but a little poor at atomizing the toner. May be used in combination.

Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate,
Examples thereof include sodium oleate, sodium laurate, sodium stearate, and potassium stearate.

When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be formed in an aqueous medium. For example, in the case of calcium sulfate, a water-insoluble calcium phosphate can be generated by mixing an aqueous solution of sodium sulfate and an aqueous solution of calcium chloride under high-speed stirring, and more uniform and fine dispersion can be achieved.

In the present invention, it is desirable to add a charge control agent to the toner material in order to control the chargeability of the toner. Examples of these charge control agents include, as positive charge control agents, nigrosine dyes, triphenylmethane dyes, quaternary ammonium salts, guanidine derivatives, imidazole derivatives, amine and polyamine compounds, and the like. Examples include metal-containing salicylic acid compounds, metal-containing monoazo dye compounds, urea derivatives, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and the like. The added amount of these charge control agents is preferably 0.1 to 10% by weight.

The additive for imparting various toner properties should have a particle diameter of 1/10 or less of the volume average diameter of the toner particles from the viewpoint of durability when added to the toner or when added to the toner. Is preferred. The particle size of this additive
The average particle diameter obtained by observing the surface of the toner particles with an electron microscope is meant. As additives for imparting these properties, for example, the following are used.

1) Fluidity imparting agents: metal oxides (such as silicon oxide, aluminum oxide, and titanium oxide), carbon black, and carbon fluoride. Those subjected to a hydrophobic treatment are more preferable.

2) Abrasives: metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, etc.) , Barium sulfate, calcium carbonate, etc.).

3) Lubricants: fluororesin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salt (zinc stearate, calcium stearate, etc.).

4) Charge controllable particles: metal oxides (such as tin oxide, titanium oxide, zinc oxide, silicon oxide, and aluminum oxide) and carbon black.

These additives are used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the toner particles.
0.1 to 5 parts by weight are used. These additives may be used alone or in combination of two or more.

When a carrier is used for the developer, a conventionally known carrier can be used. For example, magnetic materials such as iron, cobalt, and nickel, and alloys and mixtures thereof, or coatings on the surfaces thereof.

A general production example of a color toner containing the colorant of the present invention will be described.

A releasing agent, a coloring agent, a charge control agent, a polymerization initiator, and other additives are added to the polymerizable monomer, and a homogenizer, an ultrasonic dispersing machine, a media dispersing machine such as a ball mill, a sand mill, and an attritor are added. The monomer system uniformly dissolved or dispersed by the above method is dispersed in an aqueous phase containing a known dispersion stabilizer using a conventional stirrer, homomixer, homogenizer, or the like.

Preferably, the stirring speed and time are adjusted so that the monomer droplets have a desired toner particle size, generally a particle size of 30 μm or less, and granulation is performed. Thereafter, by the action of the dispersion stabilizer, stirring is performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented.

The polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers and by-products which cause odor at the time of fixing the toner, the second half of the reaction, or the end of the reaction. Later, a part of the aqueous medium may be distilled off.

After completion of the reaction, the generated toner particles are collected by washing and filtration, and dried.

If necessary, the mixture is classified with a classifier, and silica or the like is dispersed in the classified substance with a Henschel mixer or the like.

The particle size distribution measurement in the present invention will be described.

As a measuring device, Coulter Counter T
Using A-II type (manufactured by Coulter), number average distribution,
Interface to output volume average distribution (made by Nikkaki)
And CX-1 personal computer (manufactured by Canon)
And the electrolyte is 1% Na using primary grade sodium chloride.
Prepare a Cl aqueous solution.

The measuring method is as follows.
In 50 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 0.5 to 50 mg of a measurement sample is further added.

The electrolyte in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μm was measured using the Coulter Counter TA-II using a 100 μm aperture as an aperture. Is measured to obtain a volume average distribution and a number average distribution. A weight average particle diameter is obtained from the obtained volume average distribution and number average distribution.

Regarding the light fastness, JIS K-7
102 (Method A, FV type). That is, the test image was irradiated with a carbon arc lamp under the condition that water spray was not applied, and its discoloration was measured and evaluated using a blue scale.

In the present invention, fixability, offset resistance,
The evaluation method of the mixed color region and the transparency is as follows.

1) Fixing Property, Offset Resistance, and Color Mixing Area First, an appropriate amount of the above external additive is externally added to the toner containing the ester wax of the present invention to obtain a developer. An unfixed image of the obtained developer is prepared by a commercially available copying machine.

When the toner is a black toner, the fixing property and the anti-offset property are evaluated by a heat roller external fixing device having no oil application function.

Further, in the case of a mono-color toner or a full-color toner, in addition to a heat roller external fixing device having no oil application function, a commercially available full-color copying machine, CLC
-550 (manufactured by Canon Inc.), a small amount of oil is uniformly applied to the fixing roller (for example, 0.02 g / A4
Size), and evaluate the fixing property, the anti-offset property, and the color mixing area, and obtain a fixed image for evaluating the transparency.

The roller material used at this time is a fluorine-based material for both the upper and lower parts. The fixing conditions are as follows: when the transfer material is SK paper (manufactured by Nippon Paper Co., Ltd.), the nip is 6.5 mm, and the process speed is 120 mm / s.
ec, and the nip is 6.5 m when the transfer material is an OHP sheet (Pictorico Trapen for copying machine / manufactured by Asahi Glass Co., Ltd.).
m, the process speed is 30 mm / sec, and the temperature is adjusted every 5 ° C. within the temperature range of 80 ° C. to 230 ° C.

The fixing property was evaluated by applying a load of 50 g / cm ^{2 to} the fixed image (including the image offset at a low temperature) and applying it to silbon paper [Lenz Cleaning Paper “das”.
per (R) "(Ozu Paper Co. Ltd.
d)], the temperature at which the density reduction rate before and after the rubbing is less than 10% is defined as the fixing start point.

The offset resistance is determined by setting the temperature at which the offset disappears visually as the low-temperature offset starting point, and raising the temperature.
The highest temperature without offset is defined as the hot offset end point.

Further, in the mixed color area, an image in the non-offset area is converted to a handy gloss meter gloss checker IG-310.
(Horiba Seisakusho) to measure the gross, gross value 2
The area is determined by defining the area up to the maximum value.

2) Transparency The transmittance and haze (haze) of the obtained fixed image with respect to each toner amount per unit area were measured, and an image density of 1.5 was obtained.
Was used to evaluate the transparency. The method for measuring the transmittance and haze is described below.

The transmittance was measured using a Shimadzu self-recording spectrophotometer UV.
Using 2200 (manufactured by Shimadzu Corporation), the transmittance of the OHP film alone is taken as 100%, and the transmittance at the maximum absorption wavelength at 600 nm is measured.

The haze was measured using a haze meter ND.
The measurement was performed using H-300A (manufactured by Nippon Shikara Kogyo Co., Ltd.).

[0106]

The present invention will be described in detail with reference to examples.

Example 1 A 0.1 M aqueous solution of Na ₃ PO ₄ and a 1 M aqueous solution of CaCl ₂ are prepared. In a two-liter four-necked flask equipped with a high-speed stirrer TK-Homomixer, ion-exchanged water 710 was added.
Was added parts by weight and 0.1 mol -Na ₃ PO ₄ aqueous solution 450 parts by weight to adjust the rotation speed 12000 rpm for allowed to warm to 65 ° C.. 68 parts by weight of a 1.0 mol-CaCl ₂ aqueous solution is gradually added thereto, and a minute water-insoluble dispersant Ca ₃ (P
A dispersion medium system containing O ₄ ) ₂ was prepared. On the other hand, the dispersoid system contains styrene monomer 165 parts by weight n-butyl acrylate monomer 35 parts by weight

[0108]

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Saturated polyester 10 parts by weight (terephthalic acid-propylene oxide-modified bisphenol A acid value 15, peak molecular weight 6000) Salicylic acid metal compound 2 parts by weight Compound (4) (maximum peak value 64.4 ° C.) 40 parts by weight

After the above mixture was dispersed for 3 hours using an attritor, a monomer composition to which 10 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added was added to The mixture was charged into a dispersion medium and granulated for 15 minutes while maintaining the rotation speed. Then, the stirrer was changed from a high-speed stirrer to a propeller stirring blade, and the internal temperature was raised to 80 ° C.
The polymerization was continued for 10 hours by rotation. After the polymerization was completed, the slurry was cooled, and diluted hydrochloric acid was added to remove the dispersant.

By further washing and drying, the weight average diameter of the yellow toner measured by a Coulter counter was 6%.
μm, the number variation coefficient was 28%, and SF-1 was 105%.
Met. FIG. 1 shows a schematic view of a tomographic photograph of the obtained yellow toner. This shows a structure in which compound (4), which is a substance having a low softening point, is covered with a shell resin. 2% of hydrophobically treated titanium oxide was externally added to the obtained toner to obtain a toner having excellent fluidity.

To 7 parts by weight of this toner, 93 parts by weight of an acrylic resin-coated ferrite carrier were mixed, and a full color copying machine CLC5 manufactured by Canon Inc. was used as a developer.
When the image was evaluated using a remodeling machine, the temperature was 23 ° C and 6 ° C.
Under a 0% condition, a stable, clear and good yellow image was obtained without a decrease in developability even after 20,000 sheets were run.

The light resistance of the copy was good, that is, it was grades 5 and 6, and the fixability and the transparency of OHP were excellent.

Further, a copy durability test was performed on 10,000 sheets at 30 ° C. and 80% high temperature and high humidity, but no fog or the like was found.

Comparative Example 1 In the formulation of Example 1, the coloring agent was a disazo pigment (C.I.
I. Pig. Yellow 17) The same operation as in Example 1 was carried out except that the weight average diameter was changed to 3.5 parts by weight.
8 μm toner (number variation coefficient 35%, SF-1 = 11
2) was prepared and evaluated. Compared with Example 1, the saturation was particularly poor in the OHP image, and an image with a dull color tone was obtained. In addition, shaft fusion, which is considered to be polymerization inhibition, occurred during the 20,000-sheet running.

The light resistance was grade 5, and was inferior to that of Example 1 in the heat resistance test left at 100 ° C. for 10 days.

Comparative Example 2 The same operation as in Example 1 was carried out except that 50 parts by weight of paraffin wax (maximum peak value: 73.1 ° C.) was used in place of the ester wax in the formulation of Example 1, and the weight average 6.6 μm diameter toner (number variation coefficient 34%, SF-1 =
110) was prepared and evaluated. Compared to Example 1, there is no difference under the condition of 23 ° C. and 60%,
When 10,000 sheets were run under high temperature and high humidity of 80 ° C. and 80%, the chargeability could not be obtained, and fogging and the like occurred during the running, which did not reach the practical level.

Further, the image was opaque without any OHP transparency.

Comparative Example 3 A toner having a weight average diameter of 5.2 μm (number variation coefficient: 24%, SF-1 = 5.2 μm) was prepared in the same manner as in Example 1 except that the ester wax was omitted from the formulation of Example 1. 105) was prepared and evaluated. Compared with Example 1, the OHP transparency and the like are the same, but the fixing property is remarkably reduced, and
Under the conditions of 60 ° C. and 60%, the chargeability gradually decreased, fogging and the like did not reach the practical level. Also S
In the observation of the toner surface by EM, fine irregularities, which could be attributed to the pigment, were observed on the surface.

Example 2 The procedure of Example 1 was repeated except that the ester wax of the present invention was replaced by 28 parts by weight of wax F (maximum peak value: 80.2 ° C., manufactured by Hoechst) in the formulation of Example 1. The same operation was performed to obtain a toner having a weight average diameter of 6.8 μm (number variation coefficient 42%
F-1 = 110) was prepared and evaluated. Then, as in Example 1, there is no difference in the durability of 20,000 sheets, but 3
In the endurance of 10,000 sheets under high temperature and high humidity of 0 ° C. and 80%, the chargeability gradually decreased. In addition, although the image was clear and good with no scattering / fogging, the image density tended to slightly increase.

The light resistance of the copy was good, that is, grades 5 and 6, and also excellent in fixability / OHP transparency.

Example 3 In the formulation of Example 1, the amount of ester wax added was 10
Parts by weight, and further added 3 parts by weight of a surfactant, sodium dodecylbenzenesulfonate, and performed the same operation as in Example 1 except that the number of revolutions during granulation was changed to 13,000. After it was obtained, it was changed to pH 4 and further polymerized and aggregated for 4 hours while maintaining at 90 ° C.
Toner having a weight average diameter of 4.7 μm (number variation coefficient 47%,
SF-1 = 156). The same evaluation as in Example 1 was performed using the obtained toner. As a result, although the image quality was slightly poor as compared with Example 1, even in the durability of 20,000 sheets,
Even in the durability of 10,000 sheets under high temperature and high humidity, no decrease in the chargeability was observed and no scattering / fogging or the like occurred.

[0123]

[Table 1]

[0124]

As described above, the toner of the present invention not only has excellent heat and light resistance, but also can obtain a yellow toner having a higher color saturation and coloring power than conventional ones. In particular, in a suspension polymerization method in which a toner is produced by polymerizing in an aqueous medium, if the colorant has an affinity for water, the colorant is exposed on the toner surface, and phenomena such as fog are likely to occur. However, in combination with the ester wax of the present invention, a toner excellent in chargeability, fixability and OHP transparency can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of a sectional surface of a toner of the present invention in which an ester wax is encapsulated in an outer shell resin.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-6-337540 (JP, A) JP-A-6-348055 (JP, A) JP-A-60-247250 (JP, A) JP-A-63-1988 66563 (JP, A) JP-A-5-197193 (JP, A) JP-A-2-210360 (JP, A) JP-A-6-337541 (JP, A) JP-A-59-67554 (JP, A) JP-A-60-238845 (JP, A) JP-A-57-56849 (JP, A) JP-A-60-23865 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (8)

(57) [Claims] 1. A at least a polymerizable monomer, the yellow toner obtained by polymerizing directly aqueous medium in monomer composition comprising a wax and a colorant, the toner has a weight average diameter be 9μm or less A yellow toner for developing an electrostatic image, wherein the wax has an ester wax and the coloring agent has a skeleton represented by the following structural formula. Embedded image [Wherein, X _{1 to} X ₄ represent an alkyl group such as a methyl group, an ethyl group, or an (iso) propyl group, a halogen group such as a fluorine atom, a chlorine atom, or an iodine atom, or a hydrogen atom, and X _{1 to} X ₄ represent They may be the same or different. ] 2. The yellow toner for developing an electrostatic image according to claim 1, wherein the wax has at least one long-chain ester moiety having 15 or more carbon atoms. 3. The toner according to claim 1, wherein the wax and the colorant are 5 to 30% by weight and 1
3 to 9% by weight.
3. The yellow toner for developing an electrostatic image according to item 1. 4. The yellow for developing an electrostatic image according to claim 1, wherein the ester wax contains one of the substances represented by the following general formula as a main component.
Over toner. Embedded image (A, b: integers from 0 to 4; a + b = 4 R ₁ , R ₂ : an organic group having an integer of 1 to 40 carbon atoms and a carbon number difference between R ₁ and R ₂ of 3 Here, m and n are integers from 0 to 25, and m and n do not become 0 at the same time.) (A, b: integers from 0 to 4, a + b = 4, b ≠ 0 R ₁ : organic group having an integer of 1 to 40 carbon atoms, m, n: integers of 0 to 25, m and n do not become 0 at the same time.) (A, b: integers from 0 to 3; 1 ≦ a + b ≦ 3 R ₁ , R ₂ : an organic group having an integer of 1 to 40 carbon atoms and a carbon number difference between R ₁ and R ₂ Is 3 or more R ₃ : a hydrogen atom, an organic group having 1 or more carbon atoms, provided that a +
When b = 2, one of R ₃ is an organic group having 1 or more carbon atoms k: an integer of 1 to 3 m, n: an integer of 0 to 25, and m and n are simultaneously 0. It will not be. ) 5. Observation of a section of the yellow toner with a transmission electron microscope (TEM) using a transmission electron microscope (TEM) reveals that the ester wax is encapsulated in an outer resin layer and the shape factor SF-1 measured by Luzex is 100. The yellow toner for developing an electrostatic image according to any one of claims 1 to 4, wherein 6. The yellow toner has a weight average particle diameter of 4 μm.
m to 8 μm, and the number variation coefficient is 35% or less.
The electrostatic image developing method according to claim 1, wherein:
Yellow toner. 7. The monomer composition contains a polar resin.
7. The electrostatic image development according to claim 1, wherein:
For yellow toner. 8. The composition of claim 1, wherein the monomer composition is a saturated polyester resin.
The fat according to any one of claims 1 to 7, wherein the fat contains fat.
Yellow toner for developing electrostatic images.