JPH0815901A - Electrophotographic toner and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To produce an electrophotographic toner not causing blocking and having a long service life even when a bonding resin having a low softening point and fixable at low temp. is used by forming an isocyanate or polyisocyanate hardened coating film on the surface of each of the matrix particles of a toner contg. a bonding resin and a colorant. CONSTITUTION:A hardened coating film is formed on the surface of each of the matrix particles of a toner contg. a bonding resin and a colorant by a reaction of active hydrogen existing on the surface with an isocyanate or polyisocyanate to produce the objective electrophotographic toner. The isocyanate is, e.g. methyl isocyanate, isopropyl isocyanate or phenyl isocyanate. The polyisocyanate is, e.g. 2,4-tolylenediisocyanate. Polyester resin contg. hydroxyl groups is used as the bonding resin or a copolymer obtd. by copolymerizing polyethylene, a styrene-acrylic ester copolymer or epoxy resin with an active hydrogen-contg. monomer may be used.

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 an electrophotographic toner for a copying machine or printer which employs heat fixing.

[0002]

2. Description of the Related Art Recently, electrophotographic copying machines and printers are required to be fixed at a low temperature in order to reduce power consumption. In the prior art to meet this requirement,
Proposals have been made for binder resins having improved molecular weight and molecular weight distribution. Specifically, attempts have been made to lower the fixing temperature by lowering the molecular weight of the binder resin.
However, although the melting point of the toner is lowered by lowering the molecular weight of the binder resin, at the same time, the melt viscosity is also lowered, which causes a problem that an offset phenomenon to the fixing roll occurs. In order to prevent this offset phenomenon, a method of widening the low molecular weight region and the high molecular weight region of the molecular weight distribution of the binder resin, or cross-linking of the polymer portion has been performed.

However, in this method, the glass transition point of the resin is unavoidably lowered in order to provide sufficient fixing property, which causes a problem that the blocking property of the toner is deteriorated. That is, blocking occurs due to storage of toner at high temperatures, blocking of toner onto the carrier due to friction with the carrier in the developing machine, blocking of recovered toner during the cleaning process, and the like. Further, particularly in the case of the non-magnetic one-component system, the toner is rubbed on the sleeve by the blade for forming the toner layer to be charged and the layer is formed, so that stress such as heat or pressure is applied to the toner, and the toner itself is applied. If there is no heat resistance or pressure resistance, blocking of the toner on the sleeve or blade occurs, and the developability is greatly impaired.

As a method for improving the blocking property, there is known a surface modification method in which a fluidizing agent is externally added to the surface of the toner, or fine particles made of an organic material or an inorganic material are mechanically attached. However, with these methods, it is difficult to completely cover the surface of the toner with the material particles, and problems such as deterioration of fixing property and reduction of image density due to an increase in the amount of the material particles added occur. there were.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a toner having a low softening point that can be fixed at a low temperature, which is a toner having a long life and which does not cause blocking. The purpose is to

[0006]

The first electrophotographic toner according to the present invention comprises a toner mother particle containing at least a binder resin and a colorant on the surface of which active hydrogen and an isocyanate or poly are present. The toner is provided with a cured film formed by the reaction of isocyanate. Further, the second electrophotographic toner according to the present invention is characterized in that the active hydrogen of the binder resin is reacted with isocyanate or polyisocyanate on the surface of the toner mother particle containing the binder resin having at least active hydrogen and the colorant. A cured coating according to 1. is provided. Furthermore, the third electrophotographic toner according to the present invention is characterized in that at least the surface of toner mother particles containing a binder resin, a compound having active hydrogen, and a colorant,
A cured coating is provided by the reaction of active hydrogen present on the surface with isocyanate or polyisocyanate. On the other hand, the manufacturing method according to the present invention,
After forming toner mother particles containing at least a binder resin and a colorant, the toner mother particles are mixed with isocyanate or polyisocyanate, and then heat treated or mechanically impacted to give a cured coating on the surface of the toner mother particles. Is provided.

Hereinafter, the present invention will be described in detail. The isocyanate applied to the electrophotographic toner of the present invention,
Methyl isocyanate, ethyl isocyanate, isopropyl isocyanate, isobutyl isocyanate, phenyl isocyanate and the like can be mentioned. As the polyisocyanate, a trimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate and hexamethylene diisocyanate (trade name of Nippon Polyurethane Industry Co .: Coronate HX), polymerized 4,4-diphenylmethane diisocyanate (trade name: MILLIONATE M manufactured by Nippon Polyurethane Industry Co., Ltd.)
R-100) and the like.

The amount of isocyanate or polyisocyanate added to the toner for electrophotography is 0.01 to 8% by weight,
It is more preferably 0.03 to 5% by weight. If it is less than 0.01% by weight, the thickness of the coating film formed on the toner surface becomes too thin, the coating effect is not exhibited, and thus blocking is likely to occur, which is not preferable. If the amount is more than 8% by weight, the fixing property of the toner may be deteriorated, and it may take time to cure a large amount of the coating layer, which may reduce the production efficiency, which is not preferable. In particular, those in the range of 0.03% by weight to 5% by weight are more preferable because they are less likely to cause the above problems.

The toner mother particles of the electrophotographic toner of the present invention are composed mainly of a binder resin as in the case of the conventional toner. Therefore, what kind of binder resin should be used is the toner. Has a great effect on the melting start temperature of. The binder resin used in the toner mother particles of the electrophotographic toner of the present invention, a polyester resin having a hydroxyl group to form a cured coating with isocyanate or polyisocyanate, or polystyrene, styrene -Acrylic acid ester copolymer, epoxy resin and the like in which an active hydrogen-containing monomer is copolymerized can be applied.
Further, when the binder resin itself does not contain active hydrogen, the present invention can be carried out by mixing a compound having active hydrogen during hot melt kneading. Further, in order to lower the melting start temperature of the toner mother particles, it is preferable to use a resin having a molecular weight as small as possible. Resins with low molecular weight have a lower melting start temperature than resins with high molecular weight,
Further, a resin having a low glass transition point (Tg) has a lower melting start temperature than a resin having a high glass transition point, and is therefore preferably used.

Examples of the diol component of the polyester resin used in the present invention include ethylene glycol, 1,2
-Propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopenterglycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, including trivalent or higher valent Examples of polyhydric alcohols include sorbitol, 1,2,
3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol,
1,2,5-Pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene Etc.

As the acid component, fumaric acid, maleic acid, phthalic acid, isophthalic acid, itaconic acid, glutaconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, alkenylsuccinic acid, 1,2,4-benzenetricarboxylic acid,
2,5,7-naphthalene tricarboxylic acid, 1,2,5-
Hexanetricarboxylic acid, 1,3-dicarboxyl-2
-Methyl 2-methylene carboxy propane, tetra (methylene carboxylic) methane, 1,2,7,8-octane tetracarboxylic acid etc. are mentioned.

When a vinyl resin such as styrene or acrylic which originally does not contain a hydroxyl group is used as the binder resin,
It is desirable to use parahydroxystyrene, hydroxyethylhexyl acrylate, hydroxyethyl methacrylate or the like as a copolymerization component as the hydroxyl group-containing monomer.

When the binder resin does not contain active hydrogen,
In order to impart active hydrogen to the surface of the toner mother particles, it is necessary to mix a compound having active hydrogen with the mother particles. Examples of the compound include dicyandiamide, ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, 2-hydroxytrimethylenediamine, diethylenetriamine, triethylenetetraamine, diethylaminopropylamine and tetra. Examples thereof include polyamine compounds such as ethylene pentamine, an adduct of an epoxy compound and an amine, and the polyol compounds mentioned as the polyester resin component.

[0014]

In the present invention, the melting start temperature of the toner mother particles is set to 100 by selecting the binder resin to be used.
It can be controlled to be below ℃. However, if the melting start temperature of the binder resin is unnecessarily lowered, that is, if the melting start temperature is lower than 60 ° C., the toner softens in the summer, which is not preferable for storage stability. Therefore, the melting start temperature needs to be 60 ° C. or higher, which is higher than room temperature. Therefore, the melting start temperature of the binder resin used in the electrophotographic toner mother particles of the present invention is set to a temperature at which the toner can be fixed on the paper at a low temperature and which is preferable for storage stability, that is, 60 ° C. or higher and 100 ° C. or lower. Preferably.

The colorants used in the present invention include carbon black, nigrosine dye, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue and malachide green. Oxalate etc. can be mentioned. It is necessary that these colorants are contained in a sufficient concentration to form a visible image with a sufficient density, and usually 1 to 20 parts by weight of the colorant is used with respect to 100 parts by weight of the binder resin. .

As the charge control agent, conventionally used charge control agents can be used. Examples thereof include nigrosine-based dyes, quaternary ammonium salts, monoazo-based and triphenylmethane-based metal complex dyes.

Other additives that may be added as needed include a fluidizing agent. Examples of the fluidizing agent also include conventionally known resin fine particles, hydrophobic silica, colloidal silica and the like.

In order to produce the electrophotographic toner of the present invention, at least a binder resin and a pigment are blended to form toner mother particles, and then the surface of the mother particles is mixed with active hydrogen existing on the surface. It is obtained by providing a cured film of isocyanate or polyisocyanate. That is, a binder resin containing active hydrogen, a compound containing active hydrogen when the binder resin does not contain active hydrogen, a colorant,
A charge control agent, other additives as required, and the like are mixed at a desired mixing ratio, melt-kneaded using a roll mill, a pressure kneader, an extruder, a Banbury mixer, and the like, and then solidified by cooling. Jet mill,
Toner mother particles are obtained by pulverizing and classifying with a turbo mill or the like. It is also possible to use a polymerizable monomer as the binder resin and mix materials such as a coloring agent during the polymerization. Thus, the toner formed by mixing the materials at the time of polymerizing the polymerizable monomer as the binder resin is called a so-called polymerization toner. Then, the obtained toner mother particles are mixed with isocyanate or polyisocyanate to obtain a mixture, and by taking the means described below for the mixture, the active hydrogen present on the surface of the toner mother particles and the isocyanate or polyisocyanate are mixed. A cured coating is provided to obtain the electrophotographic toner of the present invention.

As a method of forming a cured coating film of active hydrogen on the surface of toner mother particles and isocyanate or polyisocyanate, the following method can be exemplified. That is, in order to react the isocyanate or polyisocyanate with active hydrogen, the mixture requires heat treatment or mechanical impact. As the heat treatment means, mixers that give high-speed shearing force, such as a super mixer, a Henschel mixer, and a turbulizer, can be used. By stirring with these mixers, frictional heat of 100 ° C. or higher is generated on the surface of the toner mother particles, and the reaction proceeds. When it is desired to further accelerate the reaction, means such as heating hot water through the jacket of the mixer or blowing hot air may be used together.

On the other hand, various devices may be used as a method for applying a mechanical impact force to the mixture. For example, a hybridization system (manufactured by Nara Machinery Co., Ltd.) that applies the high-speed air impact method, a cosmo system (manufactured by Kawasaki Heavy Industries, Ltd.), a mechanofusion system (manufactured by Hosokawa Micron) that applies the dry mechanochemical method,
Mechanomill (made by Okada Seiko Co., Ltd.), surfing system applying hot air reforming method (made by Nippon Pneumatic Mfg. Co., Ltd.), Dispercoat applying wet coating method (made by Nisshin Seifun Co., Ltd.), Coatmizer (Freund Industrial A device manufactured by the company) is preferably used, but the device is not limited to these.

The melting start temperature specified in the present invention is
It means the temperature at which the plunger starts to fall under the measurement conditions shown below. Measuring machine: Shimadzu Koka type flow tester CFT-5
00 Measuring condition: Plunger: 1 cm ² Die diameter: 1 mm Die length: 1 mm Load: 20 kgF Preheating temperature: 50-80 ° C Preheating time: 300 sec Temperature rising rate: 6 ° C / min

In the electrophotographic toner of the present invention, the binder resin and the colorant as described above and other toner components such as a charge control agent, a release agent, and a magnetic material are appropriately dispersed and contained in the toner mother particles to obtain an isocyanate. Alternatively, it is a particle having a cured film of polyisocyanate, and its average particle diameter is in the range of 5 to 20 μm. Further, a toner for electrophotography may be constituted by adding and mixing a fluidity improver made of fine silica particles or the like to the particles thus obtained.

The electrophotographic toner of the present invention is used as a one-component developer without being mixed with a two-component developer or a carrier by mixing with a carrier composed of iron powder, ferrite, granulated magnetite or the like. Good.

[0024]

The electrophotographic toner of the present invention is cured by active hydrogen and isocyanate or polyisocyanate on the surface of toner mother particles containing a binder resin having a melting start temperature of 60 ° C. or higher and 100 ° C. or lower, and a colorant. Since the toner is characterized in that a coating film is provided, blocking does not occur even if the binder resin, which occupies most of the toner weight, is placed in an environment where the temperature rises above the glass transition temperature due to heat. The electrophotographic toner of the present invention is a toner containing at least a binder resin and a colorant, and active hydrogen and isocyanate or polyisocyanate present on the toner surface of toner mother particles having a melting start temperature of 60 ° C. or higher and 100 ° C. or lower. Since the toner is characterized by having a cured coating of isocyanate, the fixing temperature of the toner is considerably lower than that of the conventional toner.

[0025]

The present invention will be described in more detail based on the following examples. In the examples, “parts” means “parts by weight”. In this example, first, toner base particles (A) having the following composition were prepared. -Polyester (non-crosslinked) resin 100 parts (monomer composition; fumaric acid / terephthalic acid / propylene oxide-modified bisphenol A) Molecular weight distribution: Mw = 8.0 × 10 ³ Mn = 4.0 × 10 ³ Hydroxyl value: 47 ( KOH mg / g) -Carbon black 6.5 parts (Mitsubishi Chemical Co., Ltd. trade name; MA-100) -Quaternary ammonium salt 2 parts (Orient Chemical Industry Co., Ltd. trade name; P-51) -Polypropylene 3 parts ( Sanyo Chemical Industry Co., Ltd. product name; Viscole 330P)

To prepare the toner mother particles, the raw materials having the above composition are mixed in a super mixer, melt-kneaded in an extruder, pulverized and classified to have an average particle diameter of 1
Positively chargeable toner mother particles (A) having a size of 1 μm were obtained. The melting start temperature of the obtained toner mother particles (A) is 92 ° C.

Example 1 To 100 parts of the toner mother particles (A), 0.01 part of a trimer of hexamethylene diisocyanate (Coronate HX manufactured by Nippon Polyurethane Industry Co., Ltd.) was added and stirred in a Henschel mixer. , Were uniformly dispersed on the surface of the toner mother particles. Then hybridization system NH
The dispersed material was put into S-1 type (manufactured by Nara Machinery Co., Ltd.) and treated at a blade tip peripheral speed of about 80 m / sec for 10 minutes to cure the toner surface to obtain an electrophotographic toner of the present invention.

Example 2 The same procedure as in Example 1 was carried out except that 0.05 part of hexamethylene diisocyanate trimer was added to 100 parts of the toner mother particles (A), and the electrophotography of the present invention was performed. To obtain toner for use.

Example 3 The same procedure as in Example 1 was carried out except that 0.05 part of hexamethylene diisocyanate trimer was added to 100 parts of the toner mother particles (A), and the electrophotography of the present invention was performed. To obtain toner for use.

Example 4 The same operation as in Example 1 was carried out except that 1.0 part of the trimer of hexamethylene diisocyanate was added to 100 parts of the toner mother particles (A), and the electrophotography of the present invention was carried out. To obtain toner for use.

Example 5 The same procedure as in Example 1 was carried out except that 5.0 parts of hexamethylene diisocyanate trimer was added to 100 parts of the toner mother particles (A), and the electrophotography of the present invention was performed. To obtain toner for use.

Example 6 The same operation as in Example 1 was conducted except that 1.0 part of hexamethylene diisocyanate (special grade reagent) was added to 100 parts of the toner mother particles (A), and the electrophotographic image of the present invention was obtained. To obtain toner for use.

Example 7 In this example, first, toner mother particles (B) having the following composition were prepared. -Styrene-acrylic acid ester copolymer resin 85 parts (monomer composition; styrene / butyl acrylate) High molecular weight material: Mw = 3.0 × 10 ⁶ Mn = 1.0 × 10 ⁶ low molecular weight material: Mw = 8.0 ^{× 10 3 Mn = 2.7 × 10} 3 low-molecular-weight material: high molecular weight = 90: 10-dicyandiamide (manufactured by Nippon carbide Industries Co., Inc.) 15 parts carbon black 6.5 parts (Mitsubishi Kasei Corporation, trade name; MA-100 ) Quaternary ammonium salt 2 parts (Orient Chemical Co., Ltd. trade name; P-51) Polypropylene 3 parts (Sanyo Chemical Co., Ltd. trade name; Viscole 330P)

To prepare the toner base particles, the raw materials having the above composition were mixed with a super mixer, melt-kneaded, and then ground and classified to obtain positively charged toner base particles having an average particle diameter of 11 μm. The melting start temperature of the obtained toner mother particles is 95 ° C. Obtained toner mother particles (B) 10
The same operation as in Example 1 was carried out except that 1.0 part of the trimer of hexamethylene diisocyanate was added to 0 part to obtain the electrophotographic toner of the present invention.

Comparative Example 1 The same operation as in Example 1 was carried out except that the trimer of hexamethylene diisocyanate was not added to 100 parts of the toner mother particles (A) to obtain a comparative electrophotographic toner. .

Comparative Example 2 In this comparative example, first, toner mother particles (C) having the following composition were prepared. Cross-linked polyester resin 100 parts (monomer composition; fumaric acid / terephthalic acid / pentaerythritol / propylene oxide-modified bisphenol A) Molecular weight distribution: Mw = 1.0 × 10 ³ Mn = 3.5 × 10 ³ Hydroxyl value: 53 ( KOH mg / g) -Carbon black 6.5 parts (Mitsubishi Chemical Co., Ltd. trade name; MA-100) -Quaternary ammonium salt 2 parts (Orient Chemical Industry Co., Ltd. trade name; P-51) -Polypropylene 3 parts ( Sanyo Chemical Industry Co., Ltd. product name; Viscole 330P)

To prepare the toner base particles, the raw materials having the above composition are mixed with a super mixer, melt-kneaded, and then ground and classified to obtain positively charged toner base particles (B) having an average particle size of 11 μm. It was The melting start temperature of the obtained toner mother particles (B) is 110 ° C. The same operation as in Example 1 was performed except that the trimer of hexamethylene diisocyanate was not added to 100 parts of the obtained toner mother particles (B).

In the evaluation of each toner in Examples 1 to 7 and Comparative Examples 1 to 2, 100 parts by weight of each toner was mixed with 0 parts of hydrophobic silica (TS-530 manufactured by Cabot Corporation). After adding 3 parts by weight, a post-treated product was used.

The blocking properties of the toners obtained in Examples 1 to 7 and Comparative Examples 1 and 2 were evaluated. To evaluate the blocking property, 20 g of the obtained toner was filled in a 150 cc bottle and left in a constant temperature bath at 50 ° C. for 48 hours, and then the caking state of the toner was visually confirmed. Table 1 shows the results.

[0040]

[Table 1]

Further, 5 parts of the toners obtained in Examples 1 to 7 and Comparative Examples 1 and 2 were mixed with 95 parts of a ferrite carrier (trade name FL-1025 manufactured by Powder Tech Co., Ltd.) to prepare a developer. . The developer thus obtained was used in a copying machine (BD-2810 manufactured by Toshiba Corp.) to confirm the toner fixability and the image quality.

The fixing property of the toner was measured by setting the heat roller temperature of the copying machine to 130 ° C., measuring the image density (A) of the image obtained by fixing the toner, and then rubbing the image with an eraser. After that, the obtained image density (B) was measured, and the fixability was confirmed by the residual ratio (%) according to the following formula. Residual rate (%) = (B / A) × 100 The residual rate of this image density is a value measured by a Macbeth reflection densitometer (trade name: RD-914, manufactured by Macbeth Co.).

The image quality is 25 ° C. and 60% RH.
A continuous printing test of 5,000 sheets was performed using the above copying machine, and a white meter (trade name; MODEL manufactured by Nippon Denshoku Industries Co., Ltd .; MODEL
Z-1001DP), the image density of the copy image at the beginning of continuous printing and the copy image after 5000 sheets (I.
It was confirmed by measuring D) and the background stain (BG) of the non-image area. The results of these measurements are shown in Table 2 below.

[0044]

[Table 2]

In Comparative Example 1, toner lumps were generated during development, and image defects were generated. From the results shown in Tables 1 and 2, it was confirmed that the toner according to the present example is excellent in blocking resistance as compared with the conventional toner, although the melting start temperature is lower. It was That is, since the electrophotographic toner according to the present embodiment is provided with a cured coating of isocyanate or polyisocyanate on the surface of toner mother particles, even if the binder resin that occupies most of the toner weight is softened by heat. Since the binder resins do not come into contact with each other, it is possible to prevent blocking from occurring.

Even when pressure is applied to the electrophotographic toner of this embodiment from the sleeve or the blade constituting the developing machine, the binder resin is covered with the cured film of isocyanate or polyisocyanate. , There is no direct contact with these members. Therefore,
According to the electrophotographic toner of this embodiment, the toner is not easily fused to the sleeve or the blade.

Further, the melting start temperature of the entire electrophotographic toner of this embodiment could be controlled to 92 ° C. Since this temperature is considerably lower than the melting start temperature of the conventional toner of 110 ° C., the heat fixing device can be maintained at a temperature considerably lower than the conventional temperature. Therefore, since the electrophotographic toner of this embodiment has excellent fixing properties even at low temperatures, the power consumption of the copying machine can be reduced.

[0048]

The electrophotographic toner according to the present invention is a toner containing a binder resin and a colorant, and active hydrogen present on the toner surface of toner mother particles having a melting start temperature of 60 ° C. or higher and 100 ° C. or lower. Since it has a cured coating of isocyanate and polyisocyanate, even if the binder resin occupying most of the weight of the toner is softened by heat, the binder resins do not come into contact with each other, so blocking occurs. Can be prevented.

The electrophotographic toner of the present invention is a toner containing at least a binder resin and a colorant, and has a cured coating film of active hydrogen and isocyanate or polyisocyanate present on the toner surface. The melting start temperature is considerably lower than the melting start temperature of the conventional toner, which is 110 ° C., and the heat fixing device can be maintained at a temperature much lower than the conventional temperature. Therefore, according to the electrophotographic toner of the present invention, it is possible to reduce the power consumption of the electrophotographic copying machine and the printer.

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[Procedure amendment]

[Submission date] July 29, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

As a method of forming a cured coating film of active hydrogen on the surface of toner mother particles and isocyanate or polyisocyanate, the following method can be exemplified. That is, in order to react the isocyanate or polyisocyanate with active hydrogen, the mixture requires heat treatment or mechanical impact. As the heat treatment means, mixers that give high-speed shearing force, such as a super mixer, a Henschel mixer, and a turbulizer, can be used. By stirring with these mixers, frictional heat of 100 ° C. or higher is generated on the surface of the toner mother particles, and the reaction proceeds. When it is desired to further accelerate the reaction, means such as heating hot water through the jacket of the mixer or blowing hot air may be used together. Well
And a surfing system applying the reforming method in hot air
You can use a product (made by Nippon Pneumatic Mfg. Co., Ltd.)
Yes.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

On the other hand, various devices may be used as a method for applying a mechanical impact force to the mixture. For example, a hybridization system (manufactured by Nara Machinery Co., Ltd.) that applies the high-speed air impact method, a cosmo system (manufactured by Kawasaki Heavy Industries, Ltd.), a mechanofusion system (manufactured by Hosokawa Micron) that applies the dry mechanochemical method,
A device such as Mechanomill (made by Okada Seiko Co., Ltd. ) is preferably used, but the device is not limited thereto.

Claims (5)

[Claims] 1. An electron, characterized in that a cured coating film formed by a reaction of active hydrogen present on the surface and isocyanate or polyisocyanate is provided on the surface of toner mother particles containing at least a binder resin and a colorant. Photographic toner. 2. A cured coating formed by the reaction of active hydrogen of the binder resin with isocyanate or polyisocyanate is provided on the surface of toner mother particles containing a binder resin having at least active hydrogen and a colorant. Characteristic electrophotographic toner. 3. A cured coating film formed by the reaction of active hydrogen present on the surface with isocyanate or polyisocyanate is provided on the surface of toner mother particles containing at least a binder resin, a compound having active hydrogen and a colorant. An electrophotographic toner characterized by the above. 4. The melting start temperature of the toner is 60 ° C. or higher and 10
4. The temperature is 0 ° C. or less, claim 1, 2 or 3.
The described electrophotographic toner. 5. Toner mother particles containing at least a binder resin and a colorant are prepared, and then isocyanate or polyisocyanate is mixed with the toner mother particles, and then heat treatment or mechanical impact is applied to the toner mother particles. A method for producing an electrophotographic toner, which comprises forming a cured coating on the surface of particles.