JP2001022127A - Flash-fixable color toner for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an excellent fixation rate of toner by incorporating a specific compound and an inorganic infrared absorbing agent in a coloring agent in combination with the coloring agent. SOLUTION: In the flash-fixable color toner for electrophotography containing a binder resin and the coloring agent, an ester compound shown by the formula and the infrared absorbing agent are incorporated in the coloring agent in combination with the coloring agent. In the formula, (m) is a positive integer of 10-30; (n) is a positive integer of 1-7. As the binder resin to be used, epoxy resin, polyester resin, polyether-polyol resin, silicone resin and the like are cited as examples. It is preferable that the ester compound shown by the formula is generally used by 1-20 wt.% on the basis of total weight of the toner. As the infrared absorbing agent used in combination with the ester compound, publicly known organic compounds having di-immonium cations, naphthalocyanine-like compounds, compounds having an azinium cation and the like are preferably exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner, and more particularly, to a developer used in various imaging apparatuses utilizing an electrophotographic system, for example, an electrophotographic copying machine, an electrophotographic printer, an electrostatic printing machine and the like. The present invention relates to a color toner for electrophotography which can be advantageously used as an electrophotographic colorant, particularly, which is optimal in a flash fixing system.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic system widely used in a copying machine, a printer, a printing machine, and the like generally includes a series of steps as follows. (1) Charge of Photoconductor A positive or negative uniform electrostatic charge is applied to the surface of a photoconductive insulator such as a photoconductor drum. (2) Exposure of photoconductor (latent image formation) After completion of the uniform charging step, the photoconductive insulator is irradiated with a light image by various means to partially erase the electrostatic charges on the insulator. To form an electrostatic latent image. For example, an electrostatic latent image corresponding to image information can be formed on a photoconductive insulator by irradiating a laser beam and erasing surface charges of a specific portion. (3) Development of Latent Image with Toner Next, a fine powder of a developer called toner is attached to the portion of the latent image on the photoconductive insulator where the electrostatic charge remains to visualize the latent image. A toner image is obtained. (4) Transfer of Toner Image to Recording Medium The toner image obtained as described above is generally electrostatically transferred to a recording medium such as recording paper in order to form a printed matter. (5) Fixing of Transferred Toner Image The toner image electrostatically transferred to the recording medium is fused and fixed by applying heat, light, pressure, or the like.

As is well known, the transfer image fixing step, which is the final step of the electrophotographic system, is performed using various methods and apparatuses. At present, as a general method, a heat roll fixing method in which the toner is melt-pressed while applying pressure to the toner with a heating roller, and a flash fixing method in which the toner is melt-fixed by irradiating light such as flash light are well known.

The heat roll fixing method has an advantage that the apparatus can be provided at a low cost because the toner is fixed under high pressure at a high temperature, and the toner fixing surface becomes smooth and the print density can be increased. On the other hand, in this fixing method, the recording paper after fixing is curled due to high temperature and rolls, and the fixing roller is contaminated with toner.
It is difficult to fix high-speed recording, which causes offset, and to fix postcards with glue on the fixing surface of paper.
It has disadvantages such as.

On the other hand, the flash fixing method can prevent the recording paper after fixing from being rolled or the occurrence of offset, and can perform high-speed recording.
There are many advantages such as no limitation on the type of recording paper used. Further, the flash fixing method has an advantage that the toner can be fixed in a non-contact manner with a recording paper or the like because the toner is melted by exposure, and for that purpose, for example, such as a seal postcard is used. This is effective for fixing images on special recording paper.

However, the flash fixing method generally has a problem that it is difficult to obtain a high print density, and it is difficult to commercialize a color toner that does not easily absorb flash light because the temperature of the toner does not increase. are doing.
Further, since the fixing of the toner is performed using the energy of the flash light (that is, the heat energy converted from the light), there is also a problem that the fixing rate of the toner greatly varies depending on the difference in the amount of light absorbed by the color tone of the color toner.

Conventionally, in order to solve the above-mentioned problems, various types of color toners for flash fixing have been proposed and put to practical use. For example, JP-A-2-11
No. 8670 is characterized in that around a core containing a colorant in a binder resin, a coating portion containing an infrared light absorbing agent in the same resin as the resin is provided by hot melting. A flash fixing color toner is disclosed. Japanese Patent Application Laid-Open No. 6-348056 discloses a color toner for flash fixing, wherein vinyl resin particles having an average particle diameter of 1 μm or less containing an infrared absorbing agent are held on the surface. I have. Further, Japanese Unexamined Patent Publication No.
Japanese Patent No. 118694 discloses a flash fixing color toner for electrophotography, wherein an infrared absorbing agent is fixed on the surface of toner particles obtained by dispersing at least a colorant in a resin. However, in the color toner in which the infrared absorbent is selectively contained only in the surface region of the toner particles, the amount of the infrared absorbent to be added is naturally limited, and therefore, it is necessary to achieve a high level of toner fixing rate. Can not. In addition, see JP-A-6-34.
In the color toner disclosed in Japanese Patent No. 8056, since the vinyl-based resin particles are derived from a styrene-based monomer and / or an acrylic-based monomer, there is also a problem that smoke and odor are generated during fixing. .

[0008] Prevention of generation of offensive odor at the time of fixing is a major problem to be solved in the flash fixing system, as well as improvement of the toner fixing rate. Explaining the mechanism of the generation of offensive odor, the flash fixing method, unlike the heat roll fixing method, employs a mechanism in which the toner is heated and fixed by flash light, so that the binder resin contained in the toner Molecules are likely to be decomposed or thermally decomposed by the action of flash light, and emit smoke and foul odor during fixing. In order to cope with this smoke generation phenomenon, in a conventional electrophotographic printer adopting a flash fixing method, a smoke removing and deodorizing filter mainly composed of activated carbon is attached near a fixing section to remove smoke. However, currently available filters have a short life span and often require replacement with new filters.

In order to improve the toner fixing rate, there is also a flash fixing toner resin composition for electrophotography disclosed in JP-A-10-39535. This toner resin composition comprises (a) indium oxide containing a VI-valent metal atom and / or F as an infrared absorber in a toner resin composition containing at least a binder resin and an infrared absorber. A metal oxide-based material, (b) a metal oxide-based material containing a V-valent metal atom and / or F in tin oxide, and (c) a group IIIB metal atom and a group IVB metal atom in zinc oxide. A metal oxide-based material containing at least one of a metal atom, a IV-valent metal atom, F and C, and (d) at least one infrared-absorbing inorganic compound of cadmium stannate It is characterized by doing. However, even with this toner resin composition, a sufficiently satisfactory toner fixing rate cannot be obtained.

[0010]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a color toner which can be used particularly in an electrophotographic process employing a flash fixing method.
An object of the present invention is to provide an electrophotographic toner that can realize an excellent toner fixing rate and can prevent generation of smoke and odor during fixing.

[0011]

According to the present invention, there is provided an electrophotographic flash fixing color toner containing a binder resin and a colorant, wherein the colorant is combined with the colorant according to the following formula (I): An ester compound represented by:

[0012]

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(Wherein m represents a positive integer from 10 to 30 and n represents a positive integer from 1 to 7), and a flash fixing color toner comprising an inorganic infrared absorbing agent. Can be achieved by:

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have found that the present invention is suitable for a flash fixing system, exhibits excellent fixing properties, and generates fumes due to the composition of the toner and an odor associated therewith. As a result of intensive research to develop a color toner having no specific color, it was found that it is effective to use an ester compound having a specific structure represented by the above formula (I) and an infrared absorber in combination with a colorant. The present invention has been completed.

The electrophotographic color toner according to the present invention comprises:
Basically, it can have the same composition as the toner conventionally used in electrophotography. That is, the color toner of the present invention is configured to include at least a binder resin and a colorant, and further includes, in addition to these main components, a combination of the above-described specific ester compound (I) and an infrared absorber.

The binder resin used in the electrophotographic color toner of the present invention is not particularly limited as long as it does not adversely affect the properties (including the properties at the time of use) of the finally obtained color toner. Of a binder resin. Suitable binder resins include, for example, epoxy resins, polyester resins, polyether-
Examples thereof include a polyol resin and a silicone resin. In addition, styrene resin, acrylic resin,
Acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, polyvinylidene chloride resins, phenolic resins, epoxy resins, etc., should not be used because they decompose when heated with flash light to produce smoke or odor. The above-mentioned binder resins may be used alone, or two or more kinds of resins may be mixed or used in combination. Further, a mixture of a linear polyester resin and a polyester resin containing a crosslinking component may be used.

Although the content of the binder resin in the toner as described above can be varied widely depending on factors such as the kind of the binder resin to be used, the composition of the toner, and the desired result, preferably, It is in the range of 60 to 90% by weight, more preferably 70 to 85% by weight, based on the total amount of the toner. The colorant to be dispersed in the binder resin in the color toner of the present invention includes many known dyes and pigments, and can be arbitrarily selected and used according to the desired color tone of the toner. The following are examples of dyes and pigments that can be advantageously implemented in the practice of the present invention.

Carbon black, monoazo red pigment,
Disazo yellow pigment, quinacridone magenta pigment, anthraquinone dye, nigrosine dye, quaternary ammonium salt dye, monoazo metal complex salt dye, aniline blue (CI No. 50405), calco oil blue (C.I. I. No. Azoic Blue 3), chrome yellow (CI. No. 14090), ultramarine blue (CI. No. 77103), Dupont oil red (CI. No. 26105), quinoline yellow ( CI No. 47005), methylene blue chloride (CI. No. 52015), phthalocyanine blue (CI. No. 74160), malachite green oxalate (CI. No. 4200)
0), lamp black (CI No. 77266),
Rose Bengal (CI No. 45435), naphthol blue black, edible red No. 2 (Amaranth, C.I.
I. No. 16185), Edible Red No. 3 (Erythrosin, CI No. 45430), Edible Red No. 40 (Alla Red AC, CI No. 16035), Edible Red No. 102 (New Coccin, CI No. .1625
5), Food Red No. 104 (Phloxine, CI No.
45410), Edible Red No. 105 (Rose Bengal,
C. I. No. No. 45440), Food Red No. 106 (Acid Red, CI No. 45100), Food Yellow No. 4 (Tartrazine, CI No. 19140), Food Yellow No. 5 (Sunset Yellow FCF, CI No. .1
5985), Edible Green 3 (First Green FC)
F, C.I. I. No. 42053), Food Blue No. 1 (Brilliant Blue FCF, CI No. 42090),
Edible Blue No. 2 (Indigo Carmine, CI No. 73
015) and others.

The above-mentioned dyes and pigments may be used alone, or may be arbitrarily mixed and used in order to obtain a desired toner color tone. Although the content of the colorant in the toner as described above can be widely changed according to a desired coloring effect or the like, usually, in order to obtain the best toner characteristics, that is, the coloring power of printing, In consideration of toner shape stability, toner scattering, etc., 0.1
It is preferably in the range of 20 to 20% by weight, and more preferably in the range of 0.5 to 10% by weight.

In the color toner for electrophotography of the present invention, it is essential to use an ester compound having a specific structure represented by the above formula (I) and an infrared absorbent in combination with the above-mentioned colorant. . These two compounds can function as fixing aids, particularly to assist and enhance the effect of flash fixing. here,
If one of these compounds is missing, satisfactory fixability cannot be obtained even if a large amount of the remaining compound is used. That is, the fixing property can be satisfied only when both are used together.

The ester compound having a specific structure includes various ester compounds within the range defined by the general formula (I). In particular, ester compounds in which m represents a positive integer from 15 to 25 and n represents a positive integer from 3 to 5 can be used advantageously. An ester compound that can be used particularly advantageously is an ester compound represented by the following formula (II).

[0022]

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The ester compound (I) as described above is
Although it can be used in various amounts in the toner, it is usually 1 to 2 based on the total amount of the toner.
It is preferably used in the range of 0% by weight, more preferably in the range of 5 to 15% by weight, and most preferably in the range of 10% by weight.
% By weight. The amount of the ester compound used is 1
If the amount is less than 20% by weight, it is inevitable that the fixing property is reduced. On the other hand, if the amount is more than 20% by weight, voids are generated on the printing surface, so-called "void resistance" is reduced.

The infrared absorber used in combination with the above-mentioned ester compound (I) is preferably a known organic diimonium-based, naphthalocyanine-based or acinium-based compound, or an inorganic tin oxide or indium-based compound. And more preferably, doped tin oxide, doped indium oxide, or a mixture of these compounds. The dopant to be doped into such an oxidized metal can be selected from appropriate substances commonly used in this technical field, but is preferably phosphorus, tin or the like. That is, a typical example of doped tin oxide is phosphorus-doped tin oxide, and a typical example of doped indium oxide is tin-doped indium oxide.

Although these infrared absorbers can be used in the form of powder, particles, etc., they are preferably in the form of particles, and the particle size of the infrared absorber is preferably
It is preferably 0.1 μm or less, as expressed by the particle diameter of the primary particles. When the particle size of the infrared absorbent exceeds 0.1 μm, not only uneven dispersion in the toner is caused to cause unsatisfactory fixing, but also fog or the like is caused to cause deterioration in print quality.

Further, the infrared absorber as described above is
Although it can be used in various amounts in the toner, it is usually 1 to 7 based on the total amount of the toner.
It is preferably used in the range of 0% by weight, more preferably in the range of 5 to 50% by weight, and most preferably in the range of 10% by weight.
-30% by weight. If the amount of the infrared absorbent is less than 1% by weight, the effect of the addition as a fixing aid cannot be obtained, while if it exceeds 70% by weight, the fixability decreases.

In the color toner for electrophotography of the present invention, various inorganic fine particles may be used as an external additive for improving the fluidity of the toner and for other purposes. The inorganic fine particles that can be used as an external additive in the present invention are usually 1
The secondary particle diameter is in the range of 5 nm to 2 mm, and more preferably in the range of 5 to 500 nm. The surface area of the inorganic fine particles is preferably in the range of 20 to 500 m ² / g, when the surface area is represented by the specific surface area by the BET method.

Examples of inorganic fine particles suitable in the practice of the present invention include, but are not limited to, those listed below: silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate,
Strontium titanate, zinc oxide, silica sand, clay,
Mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide,
Includes zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and the like. In particular, fine powder of silica can be advantageously used.

Although the inorganic fine particles as described above can be externally added in various amounts to the toner, they are usually used in an amount of 0.1 to 0.1% based on the total amount of the toner.
It is preferably used in the range of 5.0% by weight, more preferably in the range of 0.1 to 2.0% by weight, and most preferably in the range of 0.5 to 1.0% by weight. Further, in the color toner of the present invention, if necessary, in addition to the inorganic external additives described above, other conventional external additives, for example, fluorine fine particles or the like, or resin particles, for example, acrylic fine particles or the like are used. May be.

Further, the color toner for electrophotography of the present invention may have a charge control agent commonly used in this technical field for the purpose of controlling the charging characteristics of the toner. Suitable charge control agents include, for example, an electron-donating substance such as a nigrosine dye, a fatty acid metal salt, or a quaternary ammonium salt for a positively charged toner, and an azo-based metal-containing dye, chlorinated paraffin, or chlorine for a negatively charged toner. And electron-accepting substances such as activated polyester.

In the color toner of the present invention, various waxes such as low molecular weight polypropylene or polyethylene can be used as a release agent or an anti-offset agent. To summarize the above explanation,
In the practice of the present invention, the toner component as described above is:
Generally, binder resin 60 to 90% by weight Colorant 0.1 to 20% by weight Ester compound 1 to 20% by weight Infrared absorber 1 to 70% by weight Charge control agent 1 to 5% based on the total amount of toner % Wax 0 to 5% by weight External additives 0 to 5% by weight can be used. These toner components may be more or less than the above ranges as needed.

The electrophotographic color toner of the present invention can be prepared according to various procedures using the above-mentioned toner components as starting materials. For example, the color toner of the present invention is a known method such as a mechanical pulverization method in which a resin mass in which a colorant or the like is dispersed is pulverized and classified, and a polymerization method in which a monomer is polymerized while incorporating the colorant to produce fine particles. Can be prepared.
The color toner of the present invention can be advantageously prepared by the following procedure, preferably according to a mechanical pulverization method. (1) Mixing of Materials After weighing the binder resin, colorant, fixing aid (ester compound and infrared absorber), charge control agent, etc., they are uniformly mixed with a powder mixer. As the powder mixer, for example, a ball mill or the like can be used. A colorant, a charge control agent, and the like are uniformly dispersed in the resin binder. (2) Melt kneading The obtained mixture is heated and melted, and further kneaded. A screw extruder (extruder), roll mill, kneader, or the like can be advantageously used. Fineness and uniform dispersion of the colorant particles are achieved. (3) Cooling and solidification After completion of kneading, the obtained kneaded material is cooled and solidified. (4) Pulverization First, the solidified kneaded material is coarsely pulverized by a coarse pulverizer such as a hammer mill and a cutter mill, and then finely pulverized by a fine pulverizer such as a jet mill. (5) Classification After the completion of the fine pulverization, the obtained finely pulverized particles are classified in order to remove fine particles which cause a decrease in toner fluidity, toner scattering and coarse particles which cause a deterioration in image quality. As a classifier, for example, an air classifier using centrifugal force can be used. A spherical toner fine powder having an average particle size of about 0.5 to 50 μm, preferably about 1 to 15 μm is obtained. (6) Surface treatment In the final step, hydrophobic silica or titanium oxide and, if necessary, other external additives are added to the surface of the obtained toner fine powder for improving the fluidity of the toner and for other purposes. , May be attached. As the surface treatment device, for example, a high-speed flow mixer can be used.

The color toner of the present invention may be a magnetic toner or a non-magnetic toner. The developing method using the toner may be a two-component method using a carrier together or a one-component method using only a toner. May be. In the case of a two-component type color toner, various carriers commonly used in this technical field, for example, iron powder, ferrite powder and the like can be used as the carrier to be used in combination.

In particular, in the present invention, a material obtained by coating a core material can be advantageously used as a carrier for better development. Suitable materials for the carrier core include, for example, about 65 to 75 emu.
/ G manganese-strontium (Mn-Sr) -based material, high-magnetization (about 200 emu / g) iron powder, magnetite (about 90 emu / g), zinc (Cu-Zn) -based material (about 60 emu / g), etc. Can be mentioned.

The carrier core material as described above can be used preferably in the form of particles, and the average particle size of such core material particles is preferably 20 to 100 μm.
m, more preferably 60 to 90 μm. When the average particle size of the core particles is less than 20 μm, the distribution of the carrier particles includes a large number of fine powders, and the magnetization per carrier particle decreases, resulting in carrier scattering. Conversely, when the average particle size of the core material particles exceeds 100 μm, the scattering of the toner occurs as a result of the decrease in the specific surface area. Further, in the case of full-color printing having many solid portions, reproduction of the solid portions is particularly poor, which is not preferable.

The coating to be applied to the carrier core is preferably a resin coating, more preferably a silicone resin coating. This is because the silicone resin can effectively contribute to the long life of the carrier. The amount of silicone resin or other resin coating can vary widely depending on the desired effect, but is usually 0.1-5.0% by weight based on the total amount of resin-coated core material. , Preferably 0.15 to 2.0% by weight, and more preferably 0.8 to 1.5% by weight. When the amount of the resin coating is less than 0.1% by weight, the range of the surface area index (1.0 to 1.0) of the carrier core material used in the present invention is used.
In 2.1), a uniform resin coating cannot be formed on the carrier surface. Conversely, if the amount of the resin coating exceeds 5.0% by weight, the resin coating becomes too thick, resulting in a tendency for the carrier particles to be granulated, making it impossible to obtain uniform carrier particles. .

The application of a resin coating to the surface of the carrier core material can be performed according to various techniques. Preferably, after dissolving the coating-forming resin in an appropriate solvent, the resulting resin solution can be applied to the surface of the carrier core material by, for example, a dipping method, a spray method, a brushing method, or the like. Solvents that can be used for preparing the resin solution include, for example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl cellosolve acetate, and the like. These solvents may be used alone or as a mixture.

After the formation of the resin coating is completed, the solvent is evaporated by drying, followed by baking. The baking device may be either an external heating system or an internal heating system. For example, a fixed or fluid electric furnace, a rotary electric furnace, a burner furnace, or the like can be used. Further, a printing apparatus using a microwave may be used. The baking temperature is 180-3
A temperature of 00 ° C. is preferred, more preferably 220 to
The temperature is 280 ° C. If the baking temperature is lower than 180 ° C., the resin coating cannot be sufficiently solidified. Conversely, if the baking temperature exceeds 300 ° C., a part of the resin itself is decomposed, and as a result, the surface layer of the resin becomes rough, There is a possibility that a uniform resin coating cannot be obtained.

Using the color toner for electrophotography according to the present invention, an image can be formed using a method and an apparatus generally used conventionally. A typical image forming procedure is, for example, as follows. (1) Charge of Photoconductor A positive or negative uniform electrostatic charge is applied to the surface of a photoconductive insulator such as a photoconductor drum. As a photoreceptor,
For example, inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors such as polysilane and phthalocyanine can be used. (2) Exposure of photoconductor (latent image formation) After completion of the uniform charging step, the photoconductive insulator is irradiated with a light image by various means to partially erase the electrostatic charges on the insulator. To form an electrostatic latent image. For example, an electrostatic latent image corresponding to image information can be formed on a photoconductive insulator by irradiating a laser beam and erasing surface charges of a specific portion. Further, a so-called “light-back method” in which development is performed by exposing the developing section from the back side of the photoconductive insulator may be employed. (3) Development of Latent Image with Toner Next, a fine powder of a developer called toner is attached to the portion of the latent image on the photoconductive insulator where the electrostatic charge remains to visualize the latent image. This method of development, as described above,
Either one-component system or two-component system may be used. A toner image is obtained. (4) Transfer of Toner Image to Recording Medium The toner image obtained as described above is generally electrostatically transferred to a recording medium such as recording paper in order to form a printed matter. (5) Fixing of transferred toner image The toner image electrostatically transferred to the recording medium is fused and fixed by a flash fixing method. The flash fixing condition can be changed in a wide range, but is preferably in the range of 0.5 to 3.0 J / cm ^{2 of} flash light emission energy of 500 to 3,000 μs. Here, the light emission energy and the light emission time are particularly defined because if the light emission energy is strong and the light emission time is too long, the paper as a recording medium easily burns when a toner having a good fixing property is used. It is because.

[0040]

The present invention will be described below with reference to examples and comparative examples. In the following examples, “parts” means “parts by weight” unless otherwise specified.
The blending amounts of the respective toner components described in Tables 1 and 2 below are also "parts by weight". Example 1 Preparation of Toner 1 (Inventive Example) As described in Table 1 below, the following toner components were prepared in the amounts described.

Binder resin: polyester resin (manufactured by Kao) 62.5 parts Colorant: Ultramarine Blue (manufactured by Dainichi Seika) 5 parts Fixing aid: ester compound (II) (see the following formula, manufactured by NOF Corporation) 10 parts

[0042]

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Fixing aid: phosphorus-doped tin oxide 20 parts (primary particle size: 0.1 μm or less, manufactured by Catalyst Chemicals) Charge control agent: sulfonic acid polymer 1 part (manufactured by Fujikura Chemicals, trade name “FCA-1001NS”) ) Wax: propylene wax 1 part (Mitsui Chemicals, trade name “NP105”) External additive: titanium oxide (BET surface area = 200 m ³ / g) 0.5 part (Nippon Aerosil, trade name “R974”) After the toner components were put into a Henschel mixer and premixed, they were melted and kneaded by an extruder heated to 160 ° C. After cooling and solidifying the obtained kneaded material,
It was roughly pulverized by a hammer mill and further finely pulverized by a jet mill. The obtained fine powder was classified by an airflow classifier to obtain black colored fine particles having a volume average particle size of 8.5 μm. Next, 1.5 parts of hydrophobic silica fine particles (trade name “H2 manufactured by Clariant Japan”) were used based on the obtained fine particles.
000/4 ”), and the mixture was subjected to an external addition treatment using a Henschel mixer, and then classified with an airflow classifier. Average particle size8.
A 5 μm spherical toner fine powder was obtained. Hereinafter, this toner fine powder is referred to as “toner 1”. Example 2 Preparation of Toner 2 (Example of the Invention) A spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, as shown in Table 1 below, the same amount of antimony-doped tin oxide (primary particle size: 0.1 to 0.2) was used in place of the phosphorus-doped tin oxide used as a fixing aid.
1 μm or less, manufactured by Catalyst Chemicals Co., Ltd.). Hereinafter, this toner fine powder is referred to as “toner 2”. Example 3 Preparation of Toner 3 (Example of the Present Invention) Spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, as shown in Table 1 below, instead of phosphorus-doped tin oxide used as a fixing aid, the same amount of tin-doped indium oxide (primary particle size: 0.1 to 1.0) was used.
1 μm or less, manufactured by Catalyst Chemicals Co., Ltd.). Hereinafter, this toner fine powder is referred to as “toner 2”. Example 4 Preparation of Toner 4 (Comparative Example) Spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, for comparison, as shown in Table 1 below, the same amount of tin-doped indium oxide (1) was used instead of phosphorus-doped tin oxide used as a fixing aid.
Secondary particle size: 1 to 5 μm, manufactured by Catalyst Chemicals Co., Ltd.). Less than,
This toner fine powder is referred to as “toner 4”. Example 5 Preparation of Toner 5 (Comparative Example) The procedure described in Example 1 was repeated to prepare a spherical toner fine powder. In this example, for comparison, as shown in Table 1 below, the compounding amount of the ester compound (II) used as a fixing aid was reduced from 10 parts to 0.5 part and the binder resin was used as a binder resin. The amount of the polyester resin used was increased from 62.5 parts to 72 parts. Hereinafter, this toner fine powder is referred to as “toner 5”. Example 6 Preparation of Toner 6 (Example of the Invention) A spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, as shown in Table 1 below, the amount of the ester compound (II) used as the fixing aid was reduced from 10 parts to 1 part, and the amount of the polyester resin used as the binder resin was reduced. The amount was increased from 62.5 parts to 71.5 parts. Hereinafter, this toner fine powder is referred to as “toner 6”. Example 7 Preparation of Toner 7 (Example of the Present Invention) The procedure described in Example 1 was repeated to prepare a spherical toner fine powder. In this example, as shown in Table 1 below, the amount of the ester compound (II) used as a fixing aid was increased from 10 parts to 20 parts, and the amount of the polyester resin used as a binder resin was increased. The amount was reduced from 62.5 parts to 52.5 parts. Hereinafter, this toner fine powder is referred to as “toner 7”. Example 8 Preparation of Toner 8 (Comparative Example) A spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, for comparison, as shown in Table 1 below, the blending amount of the ester compound (II) used as a fixing aid was increased from 10 parts to 30 parts and used as a binder resin. The amount of the polyester resin was reduced from 62.5 parts to 42.5 parts. Hereinafter, this toner fine powder is referred to as “toner 8”. Example 9 Preparation of Toner 9 (Comparative Example) Spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, for comparison, as shown in Table 2 below, the blending amount of phosphorus-doped tin oxide used as a fixing aid was reduced from 20 parts to 0.5 part, and as a binder resin. The amount of the used polyester resin is 6
The amount was increased from 2.5 parts to 82 parts. Hereinafter, this toner fine powder is referred to as “toner 9”. Example 10 Preparation of Toner 10 (Example of the Present Invention) Spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, as shown in Table 2 below, the compounding amount of the phosphorus-doped tin oxide used as the fixing aid was reduced from 20 parts to 1 part, and the compounding amount of the polyester resin used as the binder resin was reduced. 62.5 parts to 8
The amount was increased to 1.5 parts. Hereinafter, this toner fine powder is referred to as “toner 10”. Example 11 Preparation of Toner 11 (Example of the Present Invention) Spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, as shown in Table 2 below, the compounding amount of phosphorus-doped tin oxide used as a fixing aid was increased from 20 parts to 30 parts, and the compounding amount of polyester resin used as a binder resin was increased. 62.5 parts to 5
The weight was reduced to 2.5 parts. Hereinafter, this toner fine powder is referred to as “toner 11”. Example 12 Preparation of Toner 12 (Example of the Present Invention) The procedure described in Example 1 was repeated to prepare a spherical toner fine powder. In this example, as shown in Table 2 below, the compounding amount of the phosphorus-doped tin oxide used as the fixing aid was increased from 20 parts to 50 parts, and the compounding amount of the polyester resin used as the binder resin was increased. Amount from 62.5 parts to 3
The weight was reduced to 2.5 parts. Hereinafter, this toner fine powder is referred to as “toner 12”. Example 13 Preparation of Toner 13 (Example of the Present Invention) Spherical toner fine powder was prepared by repeating the procedure described in Example 1 above. In this example, as shown in Table 2 below, the compounding amount of phosphorus-doped tin oxide used as a fixing aid was increased from 20 parts to 70 parts, and the compounding amount of polyester resin used as a binder resin was increased. 62.5 parts to 1
The weight was reduced to 2.5 parts. Hereinafter, this toner fine powder is referred to as “toner 13”. Example 14 Preparation of Toner 14 (Comparative Example) The procedure described in Example 1 was repeated to prepare a spherical toner fine powder. In this example, for comparison, as shown in Table 2 below, the blending amount of phosphorus-doped tin oxide used as a fixing aid was increased from 20 parts to 75 parts and used as a binder resin. 6 amount of polyester resin
The weight was reduced from 2.5 parts to 7.5 parts. Hereinafter, this toner fine powder is referred to as “toner 14”. Example 15 Preparation of Toner 15 (Comparative Example) The procedure described in Example 1 was repeated to prepare a spherical toner fine powder. In this example, for comparison, as shown in Table 2 below, the same amount of styrene acrylic resin (manufactured by Mitsui Chemicals) was used as the binder resin instead of the polyester resin. Hereinafter, this toner fine powder is referred to as “toner 1
5 ". Example 16 Preparation of Silicone Resin Coated Carrier Mn-Strontium (Mn-
Sr) Ferrite particles are prepared as a carrier core material, and a silicone resin (solid content: 20% by weight, manufactured by Dow Corning Toray Silicone, trade name “SR2411”) is applied to the surface of the core material using a fluidized bed. Coating was at a coverage of 0.1% by weight. After coating is completed, 250
Baking was carried out at a temperature of ° C. for 3 hours. A ferrite carrier coated with a silicone resin was obtained. Example 17 Printing Test In order to evaluate the flash fixability of the toner prepared in each of Examples 1 to 15, a printing test was performed in the following procedure.

Each toner was mixed with the silicone resin-coated ferrite carrier prepared in Example 16 to prepare a developer having a toner concentration of 4.5% by weight. High-speed printer with built-in flash fixing machine (Part No. F6760D,
(Fujitsu Co., Ltd.) was modified for negatively charged toner, and then a document pattern was continuously printed on plain paper using each developer. The process speed of the printer was 1200 mm / sec, and the toner consumption was about 1 kg / hour.

In the printing test of each toner, the following seven characteristics were evaluated. The results obtained are shown in Tables 1 and 2 below. (1) Fixability The quality of fixability was evaluated based on the peeled state of the toner print. A mending tape (manufactured by Sumitomo 3M) was attached to the print surface of the print sample with a weight of 600 g, and then peeled off. After the tape is peeled off, the change in print density on the print surface is measured by an optical densitometer, and a print density change of 10% or less is indicated as “having good fixability (shown by ○ in the table below)”.
And the others were evaluated as "poor (x)". (2) Void resistance The printed surface of the printed sample was observed with an optical microscope. If no voids (small white spots) were observed, the sample was regarded as “having good void resistance (O)”, and the other samples were evaluated. "Poor (x)". (3) Pulverizability of Toner The pulverizability of the toner during preparation of the toner was visually evaluated. Those which were able to be ground without any trouble were evaluated as “good” (○), and the others were evaluated as “bad” (×). (4) Clogging of Filter of Flash Fixing Machine After continuous printing of 1 million sheets was completed, the state of clogging of the filter of the used flash fixing machine was visually observed. A sample without slight clogging was evaluated as "good (O)", and the others were evaluated as "defective (X)". (5) Initial printing In the initial stage of printing, the quality of the printing state of the obtained print sample was visually evaluated. A sample on which satisfactory printing was performed was evaluated as "good (O)", and the others were evaluated as "defective (X)". (6) Carrier Attachment To evaluate the contamination of the printer, the presence or absence of the carrier inside the printer was visually observed. A sample that did not show any carrier adhesion was rated "good" (o), and the others were rated "bad" (x). (7) Printed state after printing 1 million sheets After printing of 1 million sheets was completed, the quality of the printed state of the obtained printed sample was visually evaluated. A sample on which satisfactory printing was performed was evaluated as "good (O)", and the others were evaluated as "defective (X)".

[0046]

[Table 1]

[0047]

[Table 2]

As can be understood from the above results, when the toner according to the present invention is used, a print having excellent flash fixability and good quality can be obtained. On the other hand, when the conventional toner is used,
Satisfactory fixability cannot be obtained. In particular, when a styrene acrylic resin is used as the binder resin as in the case of the toner 15, it is impossible to avoid the generation of smoke during flash fixing and the generation of offensive odor.

[0049]

As described above, when the color toner of the present invention is used in an electrophotographic process employing a flash fixing method, excellent fixability can be achieved without impairing the excellent characteristics of the toner itself. In addition to the fact that it is possible to prevent the generation of smoke generated during flash fixing with conventional color toners, it is possible to eliminate unpleasant odors and other unpleasant odors associated with the smoke and to eliminate complicated operations such as replacing filters. Can be.

Claims (4)

[Claims] 1. A flash fixing color toner for electrophotography comprising a binder resin and a colorant, wherein the colorant is combined with the ester compound represented by the following formula (I): (Where m represents a positive integer of 10 to 30 and n represents a positive integer of 1 to 7), and an infrared absorber. 2. The flash fixing color toner according to claim 1, wherein the infrared absorbing agent is doped tin oxide or indium oxide or a mixture thereof. 3. The infrared absorbent is in the form of particles, and the particle size is 0.1%, expressed as the particle size of primary particles.
The flash fixing color toner according to claim 1, wherein the toner particle size is not more than μm. 4. The toner according to claim 1, wherein the ester compound of the formula (I) is added in an amount of 1 to 20% by weight based on the total amount of the toner, and the infrared absorbent is contained in an amount of 1 to 20% by weight based on the total amount of the toner. The flash fixing color toner according to claim 1, wherein the color toner is added in an amount of 70% by weight.