JP3392035B2 - Manufacturing method of color toner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a color toner used for visualizing a latent image formed on an optical semiconductor in electrophotography, electrostatic recording, etc., and a color obtained by the production method. The present invention relates to a toner and a color image forming method using the color toner.

[0002]

2. Description of the Related Art In the fixing process of electrophotographic recording, a thermal pressure fixing method using a heat roll or the like is widely used from low speed to high speed. However, in this method, a so-called offset phenomenon easily occurs.

Therefore, in order to prevent this phenomenon, a release agent such as silicone oil is applied to the surface of the heat roll. However, such a method is not preferable because the fixing device becomes large and the cost becomes high, and it also becomes complicated and causes troubles.

As described above, in recent years, a toner which can be fixed on the surface of a heat roll without supplying silicone oil as much as possible has been required, and a toner containing a large amount of wax has been proposed. However, such toners tend to agglomerate with each other in the manufacturing process in which the melt-kneaded product is crushed and classified, and the particle size distribution of the resulting toner is broad, so that only images with a large fog can be obtained. In particular, since the color toner does not contain carbon black, the surface resistance is as large as about 2 to 3 times that of the black toner, and electrostatic aggregation easily occurs, and a resin having a low softening point is used to obtain good color development. Therefore, the above-mentioned problems are further increased.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, in which the supply of the release agent to the heat roll can be minimized and a good color image can be obtained. An object of the present invention is to provide a method for efficiently producing a color toner, a color toner obtained by the production method, and a color image forming method for forming a good color image using the color toner.

[0006]

MEANS FOR SOLVING THE PROBLEMS The gist of the present invention is (1) after coarsely crushing a melt-kneaded product containing a binder resin, a wax and an organic chromatic coloring material, fine particles of inorganic oxide are obtained.
A method for producing a color toner, which comprises mixing, pulverizing the obtained mixture, and classifying the mixture to obtain a melt-kneaded product.
The content of the wax in 3 to 20% by weight,
The melting point of the wax is 70 ° C. or higher and the softening point of the toner or lower.
And the supply amount of silicone oil is 10 μg / cm ²
The following color toners used for heat roll fixing
Manufacturing method , (2) Color toner obtained by the manufacturing method described in (1) above, and (3) Color toner described in (2) above is imaged on a transfer medium, and then silicone oil is supplied to a heat roll. The present invention relates to a color image forming method characterized in that fixing is performed at an amount of 10 μg / cm ² or less.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a color toner of the present invention comprises pulverizing a mixture of a melt-kneaded product containing a binder resin, a wax and an organic chromatic coloring material and inorganic oxide fine particles,
Characterized by classification.

The melt-kneaded product used in the present invention contains the binder resin, the wax and the organic chromatic color material as described above.

Examples of the binder resin include conventionally known resins such as polyester, acrylic resin, polyamide, epoxy resin, polycarbonate, polyurethane, silicone resin, fluorine resin, petroleum resin, and natural and synthetic waxes. All can be used.

In the present invention, among the above-mentioned binder resins, polyester and acrylic resin are preferable, and particularly polyester is preferable from the viewpoint of achieving both color development and durability of the toner. The polyester can be produced by a known method, for example, using the raw materials described in JP-A No. 7-49587, with reference to the production method described therein.

As the raw material monomer of the polyester, an alcohol component and a carboxylic acid component such as a carboxylic acid, a carboxylic acid anhydride or a carboxylic acid ester are used.

Examples of the alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.2) -2,2-bis (4-). (Hydroxyphenyl)
Examples include alkylene oxide adducts of bisphenol A such as propane, ethylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or etherified polyhydroxyl compounds thereof, and these may be used alone or in combination of two kinds. The above can be mixed and used.

From the viewpoint of improving the durability of the toner, it is preferable to use 5% by weight or more of an alkylene oxide adduct of bisphenol A as the alcohol component in the alcohol component.

As the carboxylic acid component, dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid and maleic acid, and alkyl or alkenyl groups having 1 to 20 carbon atoms such as dodecenylsuccinic acid and octylsuccinic acid. Examples of the compounds used for the production of ordinary polyesters such as succinic acid, trimellitic acid, pyromellitic acid, anhydrides of these acids, and lower alkyl (C1-8) esters of those acids substituted with These may be used alone or in admixture of two or more.

The polyester usually contains 1 part of the alcohol component and the carboxylic acid component in an inert gas atmosphere.
It can be produced by polycondensation at a temperature of 80 to 250 ° C. At this time, if necessary, for example, an esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, or a polymerization inhibitor such as hydroquinone monomethyl ether can be used.

The glass transition point of the polyester is preferably 40 ° C. or higher, more preferably 45 ° C. or higher from the viewpoint of ensuring storage stability and durability. In the present invention, the glass transition point can be measured using a differential scanning calorimeter.

The softening point of the polyester is 80 ° C. or higher, preferably 90 ° C., from the viewpoint of preventing cold offset.
It is desirable that the temperature is 120 ° C. or lower, preferably 110 ° C. or lower, from the viewpoints of gloss and transparency. The softening point of polyester can be measured using a Koka type flow tester, and the Koka type flow tester used in the present invention is JIS K7.
The outline is described in 210.

As the acrylic resin, various known monomers such as styrenes, monoolefins, vinyl esters, esters of ethylenic aliphatic monocarboxylic acid, vinyl ethers, vinyl ketones, and the like may be used. Can be mentioned.

As the wax, for example, low molecular weight polypropylene, low molecular weight polyethylene, synthetic wax such as sazol wax, natural wax such as carnauba wax and rice wax, coal wax such as montan wax and the like have been conventionally known. All waxes used can be used.

The melting point of the wax is 70 ° C. or higher, preferably 80 ° C., from the viewpoint of toner storage stability and durability.
It is desirable that it is above, and it is desirable that it is below the softening point of the obtained toner. If the melting point of the wax is lower than the softening point of the toner, the wax melted in the fixing process is efficiently supplied to the surface of the heat roll, so the amount of silicone oil that must be supplied from the fixing device side is greatly increased. It can be reduced. The melting point of the wax can be measured from the endothermic peak of a thermal analyzer such as a differential scanning calorimeter or a differential calorimeter, or using a Koka type flow tester.

The wax is contained in the melt-kneaded product in an amount of 1% by weight or more, preferably 3% by weight or more, in order to minimize the amount of silicone oil added to the heat roll and ensure storage stability. It is desirable that
It is desirable that the content is not more than 10% by weight, preferably not more than 10% by weight.

As the organic chromatic color material, for example, for yellow toner, for example, C.I. I. Pigment Yellow 1, the same 3, the same 12, the same 13, the same 14, the same 1
7, ibid 74, ibid 83, ibid 93, ibid 95, ibid 97, ibid 98
Yellow pigments such as C.I. I. Solvent Yellow 19, 77, 79, C.I. I. Disperse Yellow 164
For yellow dye such as magenta toner, for example,
C. I. Pigment Red 57, Same 57: 1, Same 8
No. 1, No. 122, No. 5, etc. red or red pigments, C.I. I.
Examples of red dyes such as Solvent Red 49, 52, 58, and 8 and cyan toners include C.I. I.
Pigment Blue 15: 3 and other copper phthalocyanines and their derivatives such as blue dyes and pigments.
They can be used alone or in combination of two or more.
These organic chromatic coloring materials are usually added to the melt-kneaded product in an amount of 1 to
It is preferable that the content is about 6% by weight.

The melt-kneaded product used in the present invention is, for example, a binder resin, a wax and an organic chromatic color material, which are uniformly dispersed and mixed by a known mixer such as a Henschel mixer.
Then, the mixture can be obtained by melt-kneading with a closed kneader, a single-screw or twin-screw extruder, an open roll kneader, or the like. In the present invention, a turbo mill, a jet mill or the like is used for further coarse pulverization. It is preferable that By using the coarsely pulverized melt-kneaded product, it is possible to increase the residual rate of the inorganic oxide fine particles in the toner after classification, prevent aggregation between particles,
It is possible to obtain a toner having a sharp particle size distribution.

In the present invention, if necessary, the melt-kneaded product contains a charge control agent, a magnetic substance such as ferrite, a conductivity adjusting agent, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, and a mold release agent. Additives such as agents can be included.

From the viewpoint of pulverization and classification efficiency, the average particle size of the melt-kneaded product is preferably 1.5 times or more, more preferably 2 times or more that of the color toner obtained by the production method of the present invention. From the viewpoint of the mixing efficiency of the kneaded product and the inorganic oxide fine particles, it is preferably 3 times or less that of the color toner obtained by the production method of the present invention. In addition,
The average particle diameter here is a volume average particle diameter.

Next, a mixture of the melt-kneaded product and inorganic oxide fine particles is prepared.

Examples of the inorganic oxide fine particles include:
Conventionally known inorganic oxides such as silica, alumina, titania, zirconia, tin oxide and zinc oxide can be used without particular limitation, and these can be used alone or
A mixture of two or more species can be used. In the present invention, of these, silica is preferable from the viewpoint of reducing the particle size of the toner and ensuring the fluidity.

The silica (SiO ₂ ) fine powder may be produced by a dry method or a wet method. In addition to anhydrous silica, aluminum silicate,
Although it may contain sodium silicate, potassium silicate, magnesium silicate, zinc silicate, etc.,
Those containing 85% by weight or more of SiO ₂ are preferable. Further, fine powder of silica surface-treated with a silane coupling agent, a titanium coupling agent, a silicone oil, a silicone oil having an amine in a side chain, or the like can be used.

The average particle size of the inorganic oxide fine particles is 0.001 μm from the viewpoint of preventing embedding on the toner surface.
Or more, preferably 0.005 μm or more, and from the viewpoint of securing fluidity and preventing damage to the photoreceptor, 1
It is desirable that the thickness is less than or equal to μm, preferably less than or equal to 0.1 μm. The average particle size here is a volume average particle size.

The melt-kneaded product and the inorganic oxide fine particles can be mixed with a mixer capable of high-speed stirring, such as a Henschel mixer or a super mixer.

The amount of the inorganic oxide fine particles to be mixed with the melt-kneaded product is 0.2 parts by weight or more, preferably 0. 0 parts by weight, based on 100 parts by weight of the melt-kneaded product, in order to obtain a toner having a sharp particle size distribution. The amount is preferably 5 parts by weight or more, and is 5 parts by weight or less, preferably 2 parts by weight or less with respect to 100 parts by weight of the melt-kneaded product in order to prevent generation of a large amount of free inorganic oxide.

Next, the mixture of the melt-kneaded product and the inorganic oxide fine particles is pulverized and classified.

The mixture can be pulverized by using, for example, a jet mill, and the classification can be performed by using, for example, a wind-powered classifier.

The color toner of the present invention thus obtained has a sharp particle size distribution, and its variation coefficient (standard deviation / average particle size) can be set to 15 to 30%. As a result, a good color image without fog can be obtained.

The average particle diameter of the color toner is usually 3
It is desirable that the thickness is about -20 μm, preferably about 5-10 μm. The average particle size here is a volume average particle size.

The softening point of the color toner is preferably 80 ° C. or higher, preferably 90 ° C. or higher from the viewpoint of storage stability, durability, etc., and 120 ° C. from the viewpoint of gloss, transparency and fixing property. Hereafter, it is desirable that the temperature is 110 ° C. or less. The softening point of the color toner can be measured using a Koka type flow tester.

Since the color toner of the present invention already contains the inorganic oxide fine particles, it has excellent fluidity. However, in the present invention, various external additives are further added to the surface of the obtained color toner. By adding an agent, the fluidity can be adjusted to control the transfer of toner onto the developing roll, prevent toner filming on the photoconductor, and improve the cleaning performance of residual toner on the photoconductor. Can be improved.

Examples of the external additives include inorganic oxide fine particles, fluororesin fine particles, silicone resin fine particles, higher fatty acids such as stearic acid and metal salts thereof, carbon black, fluorinated graphite, silicon carbide and boron nitride. Among these, inorganic oxide fine particles are preferable. Such inorganic oxide fine particles may be of the same type as the inorganic oxide fine particles mixed with the melt-kneaded product, or may be of another type.

The color toner of the present invention is used alone as a developer when it contains magnetic fine powder, and it is a non-magnetic one-component system developer when it does not contain magnetic fine powder. It can be used as an agent or as a two-component developer by mixing with a carrier.

The color toner of the present invention described above is obtained by mixing the melt-kneaded product with the fine particles of the inorganic oxide and then pulverizing it in the manufacturing process. Therefore, wax is added to the melt-kneaded product. Even when a large amount is added, fine pulverization can be easily carried out, a toner having a sharp particle size distribution is obtained, and an image is stable.

Therefore, the color toner of the present invention is capable of forming a good image without supplying silicone oil to the heat roll after the toner is formed on the transferred material. However, fixing can be performed with a supply amount of 10 μg / cm ² or less.

[0042]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The glass transition point of polyester, the melting point of wax and the softening point of toner are measured by the following methods.

[Glass Transition Point of Polyester] Differential Scanning Calorimeter (Seiko Denshi Kogyo KK, trade name: DSC2)
10) is used to measure at a temperature rising rate of 10 ° C./min.

[Melting point of wax and softening point of toner]
Koka type flow tester (manufactured by Shimadzu Corporation, product name:
CFT-500) is used to measure the temperature at which half of the sample flows out (heating rate: 6 ° C./min, load: 30 kg / cm).
² ).

Example 1 Polyester mainly containing propylene oxide adduct of bisphenol A, fumaric acid and terephthalic acid [softening point: 101 ° C., glass transition point: 65 ° C.] (hereinafter,
Polyester A) 70 parts by weight and C.I. I. Pigment Yellow 17 (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumika Print Yellow ST-O) was melt-kneaded using a pressure kneader to produce a pigment masterbatch.

Next, 81 parts by weight of polyester A, 10 parts by weight of masterbatch, 4 parts by weight of charge control agent (manufactured by Orient Chemical Industry Co., Ltd., product name: Bontron E-84) and carnauba wax (manufactured by Kato Yoko Co., Ltd., Product name: Carnauba wax NO1, melting point: 83 ° C) 2 parts by weight
After melt-kneading with a shaft extruder, a turbo-mill (manufactured by Turbo Industry Co., Ltd., trade name) was used to obtain a melt-kneaded product having an average particle diameter of 15 μm.

With respect to 100 parts by weight of the obtained melt-kneaded product,
Hydrophobic silica (Wacker Chemical Co., trade name: H-2
000, average particle diameter 20 nm) 1 part by weight was mixed, pulverized and classified using a jet mill and a wind type classifier to obtain a yellow toner having a softening point of 97 ° C. Coulter Multisizer (Coulter Co., Ltd.)
Manufactured by a trade name), the average particle diameter of this yellow toner is 6.4 μm (particle diameter ratio before and after pulverization = 2.
3), the coefficient of variation of particle size (standard deviation / average particle size) is 2
It was 3.4%. In addition, when the residual amount of silica in the yellow toner was measured by inductively coupled high frequency plasma spectroscopy (ICP), it was found that 88% by weight of the added silica remained.

100 parts by weight of the obtained yellow toner was mixed with hydrophobic silica (trade name: H-20, manufactured by Wacker Chemical Co., Ltd.).
00, average particle diameter 20 nm) 0.4 part by weight was further externally added. 5 parts by weight of yellow toner to which silica was externally added was mixed with 95 parts by weight of a ferrite carrier coated with a silicone resin and having an average particle diameter of 50 μm to obtain a yellow developer.

The obtained yellow developer is used as a pre-tail 55.
No. 0 (manufactured by Ricoh Co., Ltd., trade name) was mounted and a printing test was carried out. As a result, a good yellow image was stably obtained from the initial stage to 5000 sheets.

Example 2 Polyester mainly composed of propylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol A, terephthalic acid, succinic acid derivative and trimellitic acid [softening point: 115 ° C., glass transition point: 5]
9 ° C.] (hereinafter referred to as polyester B) 70 parts by weight and C.I. I. Pigment Red 57: 1 (manufactured by Dainichiseika Kogyo Co., Ltd., trade name: Seikafast Carmine 6B) 3
0 part by weight was melt-kneaded using a pressure kneader to produce a pigment masterbatch.

Next, 65 parts by weight of polyester A, 14 parts by weight of polyester B, 15 parts by weight of masterbatch and charge control agent (manufactured by Nippon Carlit Co., Ltd., trade name: LR)
-147) 1 part by weight and carnauba wax (manufactured by Kato Yoko Co., Ltd., trade name: carnauba wax NO1, melting point: 83)
C.) 5 parts by weight was melt-kneaded by a twin-screw extruder, and then a turbo mill (trade name, manufactured by Turbo Kogyo Co., Ltd.) was used to obtain a melt-kneaded product having an average particle diameter of 18 μm.

With respect to 100 parts by weight of the obtained melt-kneaded product,
Hydrophobic silica (Nippon Aerosil Co., Ltd., trade name: NA
X-50, average particle diameter 40 nm) (1 part by weight) were mixed, pulverized and classified using a jet mill and a wind classifier to obtain a magenta toner having a melting point of 102 ° C. The average particle size of this magenta toner measured with a Coulter Multisizer (trade name, manufactured by Coulter Co., Ltd.) is 7.2 μm (particle size ratio before and after pulverization =
2.5), and the variation coefficient of particle diameter (standard deviation / average particle diameter) was 21.3%. Further, when the residual amount of silica in the magenta toner was measured by ICP, it was found that 77% by weight of the added silica remained.

100 parts by weight of the obtained magenta toner was mixed with hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., trade name: R-9).
72, average particle diameter 30 nm) 0.2 part by weight was further externally added.

A magenta toner to which silica was externally added was mounted on Page Presto N-4 (trade name, manufactured by Casio Computer Co., Ltd.) which is a non-magnetic one-component developing system, and a printing test was carried out. Images were stably obtained from the initial stage to 5000 sheets.

An image printed using this toner was taken out without being fixed, and a heat roll having a diameter of 5 cm and having a silicone resin layer on the surface of which 100 cm poise of silicone oil was controlled to a supply amount of 5 μg / cm ^2. When the temperature of the heat roll was changed and the fixing possible temperature was measured using the off-line fixing machine, it was 130 ° C.
To 180 ° C., images without offset were obtained.
Further, when the image formed on the OHP was tested in the same manner, an image having sufficient transparency without offset was obtained from 140 ° C. to 180 ° C.

Example 3 70 parts by weight of polyester B and C.I. I. Pigment
30 parts by weight of Blue 15: 3 (manufactured by Sanyo Dye Co., Ltd., trade name: Cyanine Blue KRS) were melt-kneaded using a pressure kneader to produce a pigment masterbatch.

Next, 65 parts by weight of polyester A, 14 parts by weight of polyester B, 10 parts by weight of masterbatch, charge control agent (manufactured by Nippon Carlit Co., Ltd., trade name: LR-1)
47) 1 part by weight and Sazol wax (manufactured by Sazol, trade name: Sazol wax A1, melting point: 92 ° C.) 1
After melt-kneading 0 parts by weight with a twin-screw extruder, a melt-kneaded product having an average particle diameter of 20 μm was obtained using a turbo mill (manufactured by Turbo Industry Co., Ltd., trade name).

With respect to 100 parts by weight of the obtained melt-kneaded product,
Hydrophobic silica (Nippon Aerosil Co., Ltd., trade name: NA
X-50, average particle diameter 40 nm) (1 part by weight) were mixed, pulverized and classified using a jet mill and a wind classifier to obtain a cyan toner having a softening point of 98 ° C. Coulter Multisizer (Coulter Co., Ltd.)
Manufactured by a trade name), the average particle size of this cyan toner is 8.8 μm (particle size ratio before and after crushing = 2.3),
Coefficient of variation of particle size (standard deviation / average particle size) is 25.3%
Met. Further, when the residual amount of silica in the cyan toner was measured by ICP, it was found that 84% by weight of the added silica remained.

100 parts by weight of the obtained cyan toner was mixed with hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., trade name: R-97).
0.2 parts by weight (2, average particle diameter 30 nm) was further externally added to obtain a cyan toner.

A cyan toner to which silica was externally added was mounted on Page Presto N-4 (trade name, manufactured by Casio Computer Co., Ltd.), which is a non-magnetic one-component developing system, and a printing test was carried out. Images were stably obtained from the initial stage to 5000 sheets.

Further, using this toner, the printed image was taken out without being fixed, a silicone oil layer was not applied, and an offline fixing machine having a heat roll of 5 cm in diameter having a silicone resin layer on the surface was used. When the temperature of the heat roll was changed and the fixable temperature was measured, an image without offset was obtained from 120 ° C to 175 ° C.

Example 4 In the same manner as in Example 3, a melt-kneaded product having an average particle diameter of 30 μm was obtained. Hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., trade name: NAX-) based on 100 parts by weight of the obtained melt-kneaded product.
50 parts, average particle diameter 40 nm) 1 part by weight were mixed, pulverized and classified using a jet mill and a wind type classifier to obtain a cyan toner having a softening point of 99 ° C. Coulter Multisizer (manufactured by Coulter Co., Ltd.,
This cyan toner has an average particle size of 8.9 μm (particle size ratio before and after pulverization = 3.4), and a coefficient of variation in particle size (standard deviation / average particle size) of 24.7, measured using a trade name). %Met. Further, when the residual amount of silica in the cyan toner was measured by ICP, it was found that 56% by weight of the added silica remained.

100 parts by weight of the obtained cyan toner was mixed with hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., trade name: R-97).
0.2 parts by weight (2, average particle diameter 30 nm) was further externally added to obtain a cyan toner.

A cyan toner to which silica was externally added was mounted on Page Presto N-4 (trade name, manufactured by Casio Computer Co., Ltd.) which is a non-magnetic one-component developing system, and a printing test was carried out. Images were stably obtained from the initial stage to 4,500 sheets.

Using this toner, the printed image was taken out without being fixed, a silicone resin layer was not applied, and an offline fixing machine having a heat roll with a diameter of 5 cm having a silicone resin layer on the surface was used. When the temperature of the heat roll was changed and the fixable temperature was measured, an image without offset was obtained from 120 ° C to 175 ° C.

Comparative Example 1 In the same manner as in Example 3, a melt-kneaded product having an average particle size of 20 μm was obtained. The obtained melt-kneaded product was ground as it was using a jet mill and a wind-powered classifier, and classified to obtain a cyan toner. The average particle size of this cyan toner measured using a Coulter Multisizer (trade name, manufactured by Coulter Co., Ltd.) is 8.7 μm (particle size ratio before and after pulverization = 2.3), and a coefficient of variation of particle size. (standard deviation/
The average particle size was 35.9%, and only a toner having a very wide particle size distribution could be obtained.

The cyan toner thus obtained was mounted on Page Presto N-4 (trade name, manufactured by Casio Computer Co., Ltd.) which is a non-magnetic one-component developing system, and a printing test was conducted. became.

From the above results, when the melt-kneaded product was pulverized,
In comparison with Comparative Example 1 in which the inorganic oxide fine particles are not mixed, in Examples 1 to 3, it is found that a toner having a sharp particle size distribution is obtained and a good image is stably obtained. Further, from Examples 2 and 3, it can be seen that a color toner capable of fixing can be efficiently obtained without adding silicone oil to the surface of the heat roll during fixing or by adding a small amount of silicone oil.

Further, in the same manner as in Examples 1 to 3, in Example 4, a toner capable of stably obtaining a good color image but having a particle diameter of the melt-kneaded product before pulverization mixed with silica was obtained. Since the particle size is 3 times or more the particle size, the amount of silica remaining in the toner after pulverization is reduced, and the addition efficiency of silica is slightly lacking.

[0071]

According to the present invention, the supply of the releasing agent to the heat roll can be minimized and the color toner capable of good color reproduction can be efficiently produced. Furthermore, a good color image can be obtained by using the color toner of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-251970 (JP, A) JP-A-56-142541 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (4)

(57) [Claims] 1. A method in which a melt-kneaded product containing a binder resin, a wax and an organic chromatic colorant is roughly crushed , then mixed with inorganic oxide fine particles, and the resulting mixture is crushed and classified. A method for producing a color toner , which comprises:
When the content of the wax in the paste is 3 to 20% by weight
Yes, the melting point of the wax is 70 ° C. or higher, and the toner is softened.
Below the point, the supply amount of silicone oil is 10 μg /
Color toner used for heat roll fixing of cm ² or less
Manufacturing method . 2. The method for producing a color toner according to claim 1, wherein the melt-kneaded product has an average particle diameter of 1.5 to 3 times the average particle diameter of the color toner. 3. A color toner obtained by the method according to claim 1 or 2, wherein. 4. A color image forming method comprising: forming an image of the color toner according to claim 3 on a transfer target; and fixing the silicone oil to the heat roll at a supply amount of 10 μg / cm ² or less.