JP2005099528A - Mixing method, manufacturing method of toner and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixing method capable of obtaining a composition for toner manufacture suitably used for toner manufacture by using fine powder of toner produced in the toner manufacturing process, to provide a manufacturing method of toner of manufacturing toner by using the composition for toner manufacture obtained by the mixing method and to provide a toner manufactured by the manufacturing method of toner. <P>SOLUTION: The mixing method for obtaining a composition for manufacturing recycling toner by using particulate principally consisting of resin component and the toner fine powder produced in the toner manufacturing process comprises a large particle sizing process of obtaining large grain size particle by making fine particles larger grain size and the mixing process of mixing the large grain size particle and the particulate and obtaining a mixture. Therein, the mixture is preferably satisfied by the relation: 0.4≤D<SB>1</SB>/D<SB>2</SB>≤2, wherein D<SB>1</SB>is the average grain size [μm] of the particulate supplied for the mixing process and D<SB>2</SB>is the average grain size [μm] of the large grain size particle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mixing method, a toner manufacturing method, and a toner.

  A number of methods are known as electrophotographic methods. In general, a process (exposure process) of forming an electrical latent image on a photoconductor by various means using a photoconductive substance, A development step of developing the latent image with toner, a transfer step of transferring the toner image onto a transfer material (recording medium) such as paper, and a fixing step of fixing the toner image by heating using a fixing roller, etc. have.

  The toner used in the electrophotographic method as described above is manufactured through the following steps, for example. First, a material mainly containing a resin component is mixed (mixing step) and kneaded (kneading step) to obtain a kneaded product. Thereafter, the kneaded product is pulverized (pulverization step), the obtained powder is classified (classification step), and, if necessary, an external additive is added (external addition step) to complete the toner. To do.

Thus, the toner is usually produced by a method having a classification step. By performing the classification process, the particle size distribution of the toner particles becomes sharp and the image quality of electrophotography can be improved. On the other hand, if the classification step is omitted, the image quality (resolution) is reduced due to the large particles (coarse particles), and the small particles (fine powder) are firmly attached to each part of the developing machine. Problems such as fogging are likely to occur.
For this reason, in the production of the toner, a classification process is usually performed so that the particle size distribution of the toner particles is sufficiently sharp. Usually, in this classification process, 10 to 10 of the kneaded material to be used in the pulverization process. An amount of fine powder corresponding to about 40 wt% is generated. In addition, the proportion of fine powder removed in the classification step increases as the particle size distribution becomes sharper.

  As described above, a relatively large amount of fine powder is generated in the production of toner. However, from the viewpoint of saving resources and improving the yield of toner production, it is required to reuse the fine powder. Examples of such attempts include a method as disclosed in Patent Document 1. That is, after dispersing and mixing each component of the binder resin, colorant, charge control agent and release agent, the fine powder recovered in the classification step is added, and further dispersed and mixed, and then heated, melt-kneaded, and cooled and solidified. There has been proposed a method for producing recycled toner by a method of performing pulverization, classification, and external processing. However, such a method has the following problems.

  That is, the fine powder to be reused has an extremely small particle size compared to the binder resin (resin granules) used in the mixing step (usually the binder resin particle size is about 2 to 3 mm). In contrast, the particle size of the fine powder is 5 μm or less). For this reason, even if each of the above-described components and fine powder are mixed, it is difficult to obtain a mixture in which they are sufficiently uniformly mixed (for example, because the fine powder functions as a lubricant). Moreover, in such a mixture, since the fine powder and other components are not sufficiently mixed, a void (air layer) is present around the fine powder, thereby preventing contact with other components. It is in the state that was. For this reason, the said space | gap (layer of air) functions as a heat insulation layer, for example, when a mixture like the above is used for the subsequent kneading | mixing process, the heat transfer to a fine powder is a heat transfer to components other than a fine powder. It will be inferior. In addition, as described above, since the fine powder is smaller than the resin granular material, the fine powder is in a state of easily flowing between the particles of the resin granular material during the kneading step. For this reason, not only the contact between the fine powder and the resin granules is prevented, but also the contact between the resin granules is prevented. For this reason, in the kneaded material obtained through the kneading step, the fine powder is not sufficiently integrated with other components (not uniformly mixed). As a result, the obtained kneaded product has a large variation in composition at each site and is inferior in mechanical strength (becomes brittle). Also, since the fine powder component is not sufficiently integrated with the other components in the kneaded product, when the kneaded product is pulverized, the fine powder component added in the mixing step before the pulverization of the kneaded product is sufficiently advanced Tends to become fine powder again. Therefore, even if the fine powder is used for the production of toner, the effects of resource saving and yield improvement have not been sufficiently obtained. In addition, since the component added as a fine powder and other components are not sufficiently integrated (not sufficiently uniformly mixed), the toner (recycled toner) obtained in this way is vulnerable to mechanical stress. Variations in composition and characteristics among toner particles are large, and the characteristics and reliability of the toner as a whole are also poor.

Japanese Patent No. 2659873 (paragraph numbers 0018 to 0019)

  An object of the present invention is to provide a mixing method capable of obtaining a toner manufacturing composition suitably used for toner production by using toner fine powder generated in the toner manufacturing process. An object of the present invention is to provide a toner production method for producing a toner using the obtained toner production composition, and to provide a toner produced using the method.

Such an object is achieved by the present invention described below.
The mixing method of the present invention is a mixing method for obtaining a composition for producing a recycled toner using a granular material mainly composed of a resin component and toner fine powder generated in a toner production process,
Enlarging the fine powder to obtain a large particle size product,
It has the mixing process of mixing the said large particle size thing and the said granular material, and obtaining a mixture, It is characterized by the above-mentioned.
Thus, it is possible to provide a mixing method capable of obtaining a toner production composition that is suitably used for toner production by using (recycling) toner fine powder generated in the toner production process.

In the mixing method of the present invention, it is preferable that the step of increasing the particle size includes a compression / bonding step of compressing / bonding the fine powder to obtain a combined body in which a plurality of the fine powders are combined.
Thereby, a large particle size product can be obtained relatively easily and reliably. In particular, a product having a large particle size can be obtained while more reliably preventing toner components such as resin components from being modified or deteriorated.

In the mixing method of the present invention, the compression / bonding step is preferably performed using a dry compression granulator.
Thereby, a large particle size product can be obtained easily and reliably.
In the mixing method of the present invention, it is preferable that the step of increasing the particle size includes a crushing step of crushing the combined body after the compression / bonding step.
Thereby, a large-diameter product having a suitable particle size can be obtained easily and reliably.

In the mixing method of the present invention, the step of increasing the particle size preferably includes a melting / kneading step for melting and kneading the fine powder.
Thereby, the stability (stability against mechanical stress) of the large particle size product is particularly excellent.
In the mixing method of the present invention, the material temperature immediately after the melting and kneading step is preferably 80 to 150 ° C.
As a result, it is possible to obtain a large particle size product having particularly excellent stability (stability against mechanical stress) while more reliably preventing the modification and deterioration of the constituent components of the toner such as the resin component.

In the mixing method of the present invention, it is preferable that the step of increasing the particle size includes a pulverization step of pulverizing the obtained kneaded product after the melting and kneading step.
Thereby, a large-diameter product having a suitable particle size can be obtained easily and reliably.
In the mixing method of this invention, it is preferable that the average particle diameter of the said fine powder is 2-4 micrometers.
As a result, it is possible to obtain a toner manufacturing composition in which the respective components are sufficiently uniformly mixed while the fine powder having a relatively small particle diameter is efficiently reused.

In the mixing method of the present invention, the average particle size of the large particle size product is preferably 50 to 900 μm.
Thereby, in a mixing process, a large particle size thing and a granular material can be mixed more uniformly, and these can be stuck more effectively.
In the mixing method of this invention, it is preferable that the average particle diameter of the said granular material is 100-900 micrometers.
Thereby, in a mixing process, a large particle size thing and a granular material can be mixed more uniformly, and these can be stuck more effectively.

In the mixing method of the present invention, when the average particle size of the granular material subjected to the mixing step is D ₁ [μm] and the average particle size of the large particle size is D ₂ [μm], 0.4 It is preferable to satisfy the relationship of ≦ D ₁ / D ₂ ≦ 2.
Thereby, in a mixing process, a large particle size thing and a granular material can be mixed more uniformly, and these can be stuck more effectively.

In the mixing method of this invention, it is preferable that the content rate of the said large particle size thing in the material used for the said mixing process is 8-27 wt%.
Thereby, the reuse efficiency of a fine powder can be improved, making each mixture into the mixture obtained at a mixing process more uniformly mixed.
In the mixing method of this invention, it is preferable that the glass transition point of the resin component which comprises the said granular material is 48-65 degreeC.
As a result, the large particle size product and the granular material can be more uniformly mixed while sufficiently preventing modification and deterioration of the constituent components of the toner. As a result, the toner manufactured using the toner manufacturing composition is more reliable.

In the mixing method of this invention, the said mixing process is performed using the mixing apparatus which has a rotary blade, It is preferable that the peripheral speed of the said rotary blade is 10-100 m / s.
As a result, it is possible to obtain a mixture in which the components are more uniformly mixed while preventing the modification and deterioration of the constituent components of the toner.
In the mixing method of this invention, it is preferable that the processing time of the said mixing process is 5 to 30 minutes.
As a result, it is possible to obtain a mixture in which the components are more uniformly mixed while preventing the modification and deterioration of the constituent components of the toner. Further, the productivity of the toner manufacturing composition can be made sufficiently high.

The toner production method of the present invention is characterized in that a recycled toner is produced using the mixture obtained by the mixing method of the present invention.
Accordingly, it is possible to provide a method for producing a toner (recycled toner) that can sufficiently exhibit the characteristics of each component.
In the toner production method of the present invention, after the mixing step,
Kneading the mixture to obtain a kneaded product; and
It is preferable to have a pulverizing step of pulverizing the kneaded product to obtain a pulverized product.
Thereby, it is possible to obtain a toner in which the respective components are more uniformly mixed, and the characteristics of the respective constituent components can be exhibited more effectively.

In the toner production method of the present invention, it is preferable to have a classification step after the pulverization step.
Thereby, the particle size distribution of the toner particles can be sharpened. As a result, it is possible to obtain an optimum toner for forming an image with high resolution and prevention of fogging and the like.

In the toner manufacturing method of the present invention, it is preferable to use the fine powder removed in the classification step in the first mixing step.
Thereby, the recycling efficiency of fine powder is improved, and the yield of toner production is further improved. In addition, this makes the obtained toner particularly excellent in reliability.
In the toner production method of the present invention, it is preferable to have a thermal spheronization step after the pulverization step.
Thereby, toner (toner particles) having a sufficiently high circularity can be obtained.

The toner of the present invention is manufactured using the method of the present invention.
As a result, it is possible to provide a toner (recycled toner) that can fully exhibit the characteristics of each component. In addition, the toner obtained in this way is environmentally friendly because it uses fine powder generated in the toner manufacturing process.
In the toner of the present invention, the toner particles preferably have an average particle size of 5 to 9 μm.
As a result, the resolution of the image formed using the toner can be made sufficiently high, and the variation in characteristics (particularly, the variation in charging characteristics) among the toner particles can be made sufficiently small. Such inconveniences can be effectively prevented.

Hereinafter, preferred embodiments of a mixing method, a toner production method, and a toner according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view schematically showing an example of the configuration of a kneader and a cooler used in a toner manufacturing method.
First, prior to the description of the mixing method, toner production method and toner of the present invention, toner components (components of a toner production composition used for toner production) will be described.

[Components of Toner (Toner Production Composition)]
1. Resin (binder resin)
The resin (resin component) is a component that greatly contributes to the characteristics required of the toner, such as toner fixing characteristics, elastic modulus, and charging characteristics.
Examples of the resin include polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene- Vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer, styrene-α-chloro Monopolymers or copolymers containing styrene or styrene substitution products, such as methyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, styrene-vinyl methyl ether copolymer, and polyester resins , Epoxy resin, urethane modified Epoxy resin, silicone-modified epoxy resin, vinyl chloride resin, rosin-modified maleic acid resin, phenyl resin, polyethylene, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral Resins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins and the like can be mentioned, and one or more of these can be used in combination.

2. Colorant As the colorant, for example, pigments, dyes and the like can be used. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine Blue, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide and magnetic materials containing magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination. As the colorant, various color formers, fluorescent substances, phosphorescent substances, and the like may be used.

3. Wax The toner (composition for toner production) may contain a wax as a component.
By including wax in the toner (composition for toner production), for example, the releasability of toner particles can be improved.

  Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, palmitic acid. Methyl, methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax Olefin waxes such as 12-hydroxy stearamide, stearamide, phthalic anhydride amide wax, Lauro , Ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.

Melting point _{T m} of a wax is not particularly limited, but is preferably 30 to 160 ° C., and more preferably 50 to 100 ° C.. Note that, for example, by differential scanning calorimetry (DSC), the temperature is increased to 200 ° C. at a temperature increase rate of 10 ° C./min, and further the temperature decrease rate is 10 ° C./min, and then the temperature increase rate is 10 ° C./min. The melting point T _m and the heat of fusion can be determined from the measurement under the condition of increasing the temperature at

4). External additive Further, the toner (composition for toner production) may contain an external additive as a component.
Examples of the external additive include titanium oxide, silica (positively charged silica, negatively charged silica, etc.), aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, zinc oxide, alumina, magnetite, and the like. Fine particles composed of inorganic materials such as oxides, nitrides such as silicon nitride, carbides such as silicon carbide, metal salts such as calcium sulfate, calcium carbonate, and aliphatic metal salts, acrylic resins, fluororesins, polystyrene resins, polyesters Examples include resins and organic metal materials such as aliphatic metal salts (for example, magnesium stearate).
Among the external additives, examples of the titanium oxide that can be used as the external additive include rutile type titanium oxide, anatase type titanium oxide, and rutile anatase type titanium oxide.

Among the external additives, examples of silica that can be used as the external additive include positively charged silica and negatively charged silica. The positively chargeable silica can be obtained, for example, by subjecting negatively chargeable silica to a surface treatment with a silane coupling agent having a functional group such as an amino group. When negatively chargeable silica is used as an external additive, the charge amount (absolute value) of the toner particles can be increased. As a result, a stable negatively chargeable toner can be obtained, and the toner control of the image forming apparatus can be easily performed.
Examples of the external additive include liquid external additives such as straight silicone oil, polyether-modified silicone oil, carboxyl-modified silicone oil, epoxy-modified silicone oil, methacryl-modified silicone oil, amino-modified silicone oil, and aminopolyether silicone oil. An agent may be used.

Further, as the external additive, HMDS, a silane coupling agent (for example, one having a functional group such as an amino group), titanate coupling agent on the surface of the fine particles composed of the above-described materials. In addition, a surface treatment (for example, a hydrophobization treatment or the like) with a fluorine-containing silane coupling agent, silicone oil, or the like may be used.
Further, at least a part of the components used as the external additive may be contained in the toner particles in the finally obtained toner.

5). Other Components The toner (toner production composition) may contain components other than the resin, colorant, wax, and external additive as its constituent components. Examples of such components include a charge control agent, a dispersant, and magnetic powder.
Examples of the charge control agent include benzoic acid metal salts, salicylic acid metal salts, alkyl salicylic acid metal salts, catechol metal salts, metal-containing bisazo dyes, nigrosine dyes, tetraphenylborate derivatives, quaternary ammonium salts, Examples thereof include alkyl pyridinium salts, chlorinated polyesters, and nitrofunic acid.

Examples of the dispersant include metal soap, inorganic metal salt, organic metal salt, and polyethylene glycol.
Examples of the metal soap include tristearic acid metal salts (for example, aluminum salts), distearic acid metal salts (for example, aluminum salts, barium salts, etc.), stearic acid metal salts (for example, calcium salts, lead salts, zinc salts, etc.) ), Linolenic acid metal salts (eg, cobalt salts, manganese salts, lead salts, zinc salts, etc.), octanoic acid metal salts (eg, aluminum salts, calcium salts, cobalt salts, etc.), oleic acid metal salts (eg, calcium salts) , Cobalt salts, etc.), palmitic acid metal salts (eg, zinc salts, etc.), naphthenic acid metal salts (eg, calcium salts, cobalt salts, manganese salts, lead salts, zinc salts, etc.), resinic acid metal salts (eg, calcium Salt, cobalt salt, manganese salt, lead salt, zinc salt, etc.).

  Examples of the inorganic metal salt and the organic metal salt include a cation of an element selected from the group consisting of metals of Group IA, Group IIA, and Group IIIA of the periodic table as a cationic component, and an anion Examples of the property component include salts containing an anion selected from the group consisting of halogen, carbonate, acetate, sulfate, borate, nitrate, and phosphate.

Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides such as Fe, Co, and Ni. The thing comprised with the magnetic material containing a magnetic metal etc. are mentioned.
In addition to the above materials, for example, zinc stearate, zinc oxide, cerium oxide, or the like may be used as an additive.

[Mixing method]
Next, a mixing method for obtaining a toner composition composed of the above components will be described.
The mixing method of the present invention uses a granular material mainly composed of the resin component (resin) as described above (hereinafter also referred to as “resin granular material”) and toner fine powder generated in the toner manufacturing process. A method of mixing to obtain a composition for producing recycled toner (a composition for producing toner), the step of enlarging the fine particles to obtain a large particle size, a large particle size obtaining step, a large particle size product and a resin And a mixing step of mixing the granule to obtain a mixture.
Hereinafter, the fine powder and the resin granular material will be described, and then the particle size increasing step, the particle size increasing product, the mixing step, and the mixture (composition for toner production) will be described.

<Fine powder>
The fine powder used in the present invention is not particularly limited as long as it is a fine powder of toner generated in the toner production process, but it is usually composed mainly of a resin component (resin).
The resin component that constitutes the fine powder may have substantially the same composition as that of the resin component that constitutes the resin granule described in detail later, or may have a different composition.
Further, the fine powder may or may not be generated by the toner production method of the present invention as described later. For example, the fine powder may be generated in the production process of a toner having a composition different from that of the toner of the present invention.

The average particle diameter of the fine powder is not particularly limited, but is preferably 2 to 4 μm. When the average particle size of the fine powder is within such a range, the material is sufficiently uniformly mixed even when the proportion of the fine powder in the material used in the mixing step described later is relatively large. be able to. Therefore, it is possible to obtain a toner production composition in which the respective components are sufficiently uniformly mixed while efficiently reusing fine powder having a relatively small particle size.
The fine powder may be, for example, one containing an external additive as described above (one with an external additive added).

<Granular body (resin granular body)>
The resin granule is not particularly limited as long as it is mainly composed of a resin component, and may be substantially composed only of a resin component, or may be a component other than a resin component (for example, the coloring described above) Agents, waxes, charge control agents, dispersants, magnetic powders, etc.). However, when the resin granule contains a component other than the resin component, the ratio of the resin component in the resin granule is preferably 85 wt% or more, more preferably 90 wt% or more, and 95 wt% or more. More preferably. If the proportion of the resin component in the resin granule is too small, depending on the glass transition point of the resin component or the amount (ratio) of the large particle size to be described later, in the mixing step described later, the large particle size and the granular material It may be difficult to mix (resin granules) sufficiently uniformly, and it may be difficult to obtain a toner manufacturing composition in which these are sufficiently adhered.

In the present invention, a plurality of different types of resin granules (different in composition, shape, etc.) may be used.
The average particle size of the resin granules is preferably 100 to 900 μm, and more preferably 200 to 500 μm. When the average particle size of the resin granules is within such a range, the fine powder and the resin granules can be more uniformly mixed and more effectively adhered in the mixing step described later. In addition, when the average particle size of the resin granules is within this range, the handleability of the resin granules is excellent.

<Step of increasing particle size>
In the step of increasing the particle size, the fine powder as described above is increased in particle size to obtain a large particle size product.
The method for obtaining the large particle size product is not particularly limited, and examples thereof include the following methods (I) and (II).
(I) A method having a compression / binding step of compressing / binding fine powder to obtain a combined body (secondary particles) in which a plurality of fine powders are combined.

By adopting such a method, a large particle size product can be obtained relatively easily and reliably. In particular, a product having a large particle size can be obtained while more reliably preventing toner components such as resin components from being modified or deteriorated.
When employing such a method, the compression / bonding step is preferably performed using a dry compression granulator. Thereby, a large particle size product can be obtained easily and reliably. Examples of the dry compression granulator include a roller compactor (manufactured by Kurimoto Steel Co., Ltd.) and a roller compactor (manufactured by Freund Sangyo Co., Ltd.).

  Moreover, in such a method, it is preferable to have the crushing process which crushes a conjugate | bonded body after a compression and a joint process. Thereby, a large-diameter product having a suitable particle size can be obtained easily and reliably. In addition, the bonded body can be separated at a site where the binding force is relatively weak among the binding sites of the plurality of fine powders constituting the bonded body. It is possible to effectively prevent unintentional separation of the particle size product).

  The crushing step can be performed using, for example, various crushing apparatuses such as a Henschel mixer, a jet mill, a ball mill, a pin mill, a hammer mill, and a feather mill, a crushing apparatus, and the like. Specifically, Mitsui Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), Q type mixer (manufactured by Mitsui Mining Co., Ltd.), super mixer (manufactured by Kawata Co., Ltd.), IDS mill (manufactured by Nippon Pneumatic Industrial Co., Ltd.), micron jet (Manufactured by Hosokawa Micron Corporation), FM-1P (manufactured by Hosokawa Micron Corporation) or the like.

  Moreover, you may perform various post-processes, such as a classification process, as needed after a compression coupling | bonding process and a crushing process. By performing the classification treatment, the particle size distribution of the large particle size product can be sharpened. As a result, in the subsequent mixing step, the large particle size product and the granular material (resin granular material) can be more uniformly mixed. A classification process (classification process) can be performed using a sieve, an airflow classifier, etc., for example.

Further, the classification process (classification process) may be performed simultaneously with the above-described crushing process (crushing process).
Moreover, you may use the fine powder which generate | occur | produced (obtained) by the above crushing processes, a classification process (classification process), etc. as a material for large particle size preparation, for example. Thereby, the recycling efficiency of fine powder is improved, and the yield of toner production is further improved. In addition, this makes the obtained toner particularly excellent in reliability.

(II) A method having a melting / kneading step of melting / kneading fine powder.
By adopting such a method, the stability (stability against mechanical stress) of the resulting large particle size product is particularly excellent. As a result, unintentional separation of the large particle size product can be effectively prevented in the mixing step and kneading step described later. Moreover, since the stability (stability against mechanical stress) of the resulting large particle size product is particularly excellent, the large particle size product obtained by the pulverization step described below (particularly the melting and kneading step) is pulverized. In the pulverization step), the amount of newly generated fine powder can be suppressed. As a result, toner productivity is improved.

When such a method is adopted, the material temperature immediately after the melting and kneading step is preferably 80 to 150 ° C, more preferably 90 to 110 ° C. As a result, it is possible to obtain a large particle size product having particularly excellent stability (stability against mechanical stress) while more reliably preventing the modification and deterioration of the constituent components of the toner such as the resin component.
Moreover, in such a method, it is preferable to have the crushing process which grind | pulverizes the kneaded material obtained after a melting and kneading | mixing process. Thereby, a large-diameter product having a suitable particle size can be obtained easily and reliably.

The pulverization step can be performed using various pulverization apparatuses such as a ball mill, a vibration mill, a jet mill, a pin mill, a feather mill, and a rotor rotation type mill, and a crushing apparatus.
In addition, after the pulverization step, various post treatments such as classification treatment may be performed as necessary.
In addition, after the melting / kneading step and the pulverizing step, various post-treatments such as a classification treatment may be performed as necessary. By performing the classification treatment, the particle size distribution of the large particle size product can be sharpened. As a result, in the subsequent mixing step, the large particle size product and the granular material (resin granular material) can be more uniformly mixed. A classification process (classification process) can be performed using a sieve, an airflow classifier, etc., for example.

The classification process (classification process) may be performed simultaneously with the above-described pulverization process (pulverization process).
Moreover, you may use the fine powder which generate | occur | produced (obtained) by the above grinding | pulverization processes, a classification process (classification process), etc. as a material for large particle size preparation, for example. Thereby, the recycling efficiency of fine powder is improved, and the yield of toner production is further improved. In addition, this makes the obtained toner particularly excellent in reliability.

<Large particle size>
By the large particle size increasing step as described above, a large particle size product obtained by increasing the particle size of the fine powder is obtained.
The average particle size of the large particle size product is not particularly limited, but is preferably 50 to 900 μm, and more preferably 200 to 700 μm. Thereby, in a mixing process, a large particle size thing and a resin granular material can be mixed more uniformly, and these can be stuck more effectively. However, in this specification, the “average particle size of the large particle size product” refers to the apparent average particle size. For example, when the large particle size product is a secondary particle, The average particle size of the secondary particles is referred to as “average particle size of the large particle size product”.

In addition, when the average particle diameter of the resin granules used in the subsequent mixing step is D ₁ [μm] and the average particle diameter of the large particle size is D ₂ , 0.4 ≦ D ₁ / D ₂ ≦ 2. It is preferable to satisfy this relationship, and it is more preferable to satisfy the relationship 0.4 ≦ D ₁ / D ₂ ≦ 1.2. By satisfying such a relationship, in the subsequent mixing step, the large particle size product and the resin granular material can be mixed more uniformly, and these can be more effectively adhered to each other.

<Mixing process (mixing process)>
In the mixing step, the large particle size product and the resin granules as described above are mixed. As described above, in the present invention, since the fine powder is increased in particle size prior to the mixing step, the increased particle size and the resin granular material can be easily and uniformly mixed. In contrast, when the fine powder is directly mixed with the resin granules without increasing the particle size, the components cannot be mixed sufficiently uniformly. More specifically, when a fine powder that has not been increased in particle size and a resin granule are mixed, the fine powder having an extremely small particle size becomes an aggregate and segregates, so that the fine powder is uniformly mixed with the resin granule. I can't fit.

  In addition, the material subjected to the mixing step may contain components other than the large particle size product and the resin granules. For example, in the material used for the mixing step, particles mainly composed of a colorant (colorant particles), particles mainly composed of wax (wax particles), and mainly a charge control agent. At least one selected from the group consisting of configured granules (charge control agent granules) may be included. In such a case, the average particle diameter of the granular material other than the resin granular material is preferably about 1 to 2000 μm. More specifically, the average particle diameter (secondary particle diameter) of the colorant granules is preferably about 1 to 100 μm, and more preferably about 50 to 100 μm. The average particle size of the wax granules is preferably about 500 to 2000 μm, and more preferably about 500 to 1000 μm. The average particle size (secondary particle size) of the charge control agent granules is preferably about 50 to 100 μm, and more preferably about 50 to 100 μm. When the average particle size of the granular material (a granular material other than the resin granular material) is within such a range, a mixture in which the components are more uniformly mixed can be obtained in the mixing step.

  Moreover, the mixing process may be performed in two or more stages. For example, the mixing step includes a first mixing step of mixing a large particle size product and a resin granule, a first mixture obtained in the first mixing step, and a granule mainly composed of wax (wax And a second mixing step of mixing at least one selected from the group consisting of particles (charge control agent particles) mainly composed of a charge control agent. . For example, when using at least 2 or more types of resin granular material (resin component), a mixing process mixes the large particle size thing and the 1st resin granular material which mainly has the 1st resin component. A first mixing step for obtaining a first mixture, a first mixture, and a second resin granule mainly composed of a second resin component having a glass transition point higher than that of the first resin component are mixed. And a second mixing step. Thus, in the first mixing step, the large particle size product and the first resin granular material can be more effectively adhered (attached), and the mixture obtained as the toner manufacturing composition is converted into a large particle size. There can be almost no voids (air layer) around the compound (fine powder constituting the large particle size product). As a result, it becomes possible to knead the composition for producing the toner more uniformly in the kneading step described later, and the toner finally obtained also has high characteristics and high reliability.

The content of the large particle size product in the material subjected to the mixing step is preferably 8 to 27 wt%, and more preferably 10 to 25 wt%. Thereby, the reuse efficiency of a fine powder can be improved, making each mixture into the mixture obtained at a mixing process more uniformly mixed.
The mixing step may be performed using any apparatus, but is preferably performed using a mixing apparatus having rotating blades. Thereby, a mixing process (mixing process) can be performed efficiently in a short time.

When performing a mixing process using the above mixing apparatuses, the peripheral speed (tip peripheral speed) of the rotary blade is preferably 10 to 100 m / s, more preferably 30 to 60 m / s, and 40 More preferably, it is -50 m / s. As a result, it is possible to obtain a mixture in which the components are more uniformly mixed while preventing the modification and deterioration of the constituent components of the toner.
Moreover, it is preferable that the processing time (mixing time) of a mixing process is 2 to 30 minutes, and it is more preferable that it is 2 to 20 minutes. As a result, it is possible to obtain a mixture in which the components are more uniformly mixed while preventing the modification and deterioration of the constituent components of the toner. Further, the productivity of the toner manufacturing composition can be made sufficiently high.

<Mixture (composition for toner production)>
By the mixing method as described above, a mixture (composition for toner production) suitably used for the production of toner can be obtained. Further, the toner production composition obtained as described above is prepared (recycled) using toner fine powder generated in the toner production process, so that resource saving and improvement in toner production yield are achieved. This is also advantageous from the viewpoint of.

[Toner Production Method]
Next, a method using a kneading and pulverizing method will be described as an example of the production method of the present invention for producing a toner using the toner production composition (mixture) obtained by the mixing method as described above. By using a kneading and pulverizing method (that is, a method having a kneading step of kneading a mixture to obtain a kneaded product and a step of pulverizing the kneaded product to obtain a pulverized product), a toner in which each component is mixed more uniformly is obtained. It can obtain efficiently and can exhibit the characteristic of each component more effectively. Further, as described above, the mixture (composition for toner production) obtained by the mixing method of the present invention is a mixture in which each component (particularly fine powder and resin) is sufficiently uniformly mixed. Therefore, in this step, a kneaded material in which the components are mixed more uniformly can be obtained.

<Kneading process>
The mixture 5 as described above is kneaded using a kneader 1 as shown in FIG.
This embodiment demonstrates the structure which uses a biaxial kneading extruder as a kneading machine.
The kneading machine 1 includes a process unit 2 that kneads the mixture 5 while conveying the mixture, a head unit 3 that extrudes a kneaded product 7 formed by kneading the mixture 5 into a predetermined cross-sectional shape, and a mixture 5 in the process unit 2. And a feeder 4 for supplying the feed.

The process unit 2 includes a barrel 21, a screw 22 and a screw 23 inserted into the barrel 21, and a fixing member 24 for fixing the head unit 3 to the tip of the barrel 21.
In the process part 2, when the screw 22 and the screw 23 rotate, a shearing force is applied to the mixture 5 supplied from the feeder 4, and the kneaded material 7 in which the components are more uniformly mixed is obtained.

  The total length of the process part 2 is preferably 50 to 300 cm, and more preferably 100 to 250 cm. If the total length of the process part 2 is less than the lower limit, depending on the temperature in the process part 2 and the like, it may be difficult to knead the mixture 5 sufficiently uniformly. On the other hand, when the total length of the process unit 2 exceeds the upper limit, depending on the temperature in the process unit 2, the number of rotations of the screw 22 and the screw 23, etc., the mixture 5 is easily denatured by heat, and finally obtained. It may be difficult to sufficiently control the physical properties of the toner. On the other hand, if the total length of the process unit 2 is too long, the toner productivity decreases.

The raw material temperature (mixture temperature) T ₁ in the process part 2 varies depending on the composition of the resin component (for example, the resin component constituting the resin granule, the resin component constituting the fine powder, etc.), but is 50 to 300 ° C. It is preferable that it is 60 to 250 ° C. When the raw material temperature in the process part 2 is less than the lower limit, the viscosity of the mixture 5 at the time of kneading becomes high, and it may be difficult to knead the mixture 5 sufficiently uniformly. On the other hand, when the raw material temperature in the process unit 2 exceeds the upper limit, depending on the total length of the process unit 2, the number of rotations of the screw 22 and the screw 23, etc., the mixture 5 is likely to be denatured by heat. It may be difficult to sufficiently control the physical properties of the obtained toner. In the process unit 2, the raw material temperature may be uniform or different depending on the part. In the latter case, the maximum temperature of the mixture 5 in the process section 2 is preferably higher than the lower limit, and the minimum temperature and the maximum temperature of the mixture 5 in the process section 2 are preferably within the above range. preferable.

  Further, the residence time (time required for passage) of the mixture 5 in the process section 2 is preferably 1 to 25 minutes, and more preferably 2 to 15 minutes. If the residence time in the process unit 2 is less than the lower limit, depending on the temperature in the process unit 2 and the like, it may be difficult to knead the mixture 5 sufficiently uniformly. On the other hand, when the residence time in the process unit 2 exceeds the upper limit, the production efficiency is lowered. Depending on the temperature in the process unit 2, the number of rotations of the screw 22 and the screw 23, and the like, Modification tends to occur, and it may be difficult to sufficiently control the physical properties of the finally obtained toner.

  The number of rotations of the screw 22 and the screw 23 varies depending on the composition of the mixture 5 (particularly, the resin composition and the fine powder composition), but is preferably 50 to 600 rpm. If the number of rotations of the screw 22 and the screw 23 is less than the lower limit value, it may be difficult to knead the mixture 5 sufficiently uniformly depending on, for example, the temperature in the process unit 2. On the other hand, when the rotation speed of the screw 22 and the screw 23 exceeds the upper limit, the resin molecules are cut by shearing, and the characteristics of the resin easily deteriorate.

The kneader 1 may have a vacuum pump (not shown) that degass the inside of the process unit, for example. Thereby, it can prevent that the pressure in the process part 2 becomes high too much by the heating, heat_generation | fever, etc. at the time of kneading | mixing, and a kneading process can be performed more safely and efficiently.
Moreover, although it is preferable that the material used for the kneading step is substantially composed only of the mixture 5, it may contain components other than the mixture 5.

<Extrusion process>
The kneaded material 7 kneaded in the process unit 2 is pushed out of the kneader 1 through the head unit 3 by the rotation of the screw 22 and the screw 23.
The head unit 3 has an internal space 31 into which the kneaded product 7 is fed from the process unit 2 and an extrusion port 32 through which the kneaded product 7 is extruded.
The temperature of the kneaded product 7 in the internal space 31 (at least the temperature in the vicinity of the extrusion port 32) T ₂ [° C.] varies depending on the composition of the mixture 5 used in the kneading step, but is about 80 to 150 ° C. Is preferred. Temperature T ₂ of the kneaded material 7, With such a temperature, while sufficiently preventing the formation of such a resin component, the kneaded material 7 can be pushed easily and reliably from the extrusion port 32.

In the illustrated configuration, the internal space 31 has a cross-sectional area gradually decreasing portion 33 in which the cross-sectional area gradually decreases in the direction of the extrusion port 32.
By having such a cross-sectional area gradually decreasing portion 33, the extrusion amount of the kneaded material 7 extruded from the extrusion port 32 is stabilized, and the cooling rate of the kneaded material 7 in the cooling step described later is stabilized. As a result, the toner manufactured using the toner has a particularly small variation in characteristics among the toner particles, and has excellent overall characteristics.

<Cooling process>
The softened kneaded product 7 extruded from the extrusion port 32 of the head unit 3 is cooled by the cooler 6 and solidified.
The cooler 6 has rolls 61, 62, 63, 64 and belts 65, 66.
The belt 65 is wound around a roll 61 and a roll 62. Similarly, the belt 66 is wound around a roll 63 and a roll 64.

  The rolls 61, 62, 63, 64 rotate about the rotation shafts 611, 621, 631, 641 in the directions indicated by e, f, g, h in the figure. Thereby, the kneaded material 7 extruded from the extrusion port 32 of the kneader 1 is introduced between the belt 65 and the belt 66. The kneaded material 7 introduced between the belt 65 and the belt 66 is cooled while being formed into a plate shape having a substantially uniform thickness. The cooled kneaded material 7 is discharged from the discharge part 67. The belts 65 and 66 are cooled by a method such as water cooling or air cooling. When such a belt type is used as the cooler, the contact time between the kneaded product extruded from the kneader and the cooling body (belt) can be increased, and the cooling efficiency of the kneaded product is particularly excellent. Can be.

  By the way, when the mixture 5 contains two or more components that are incompatible and dispersible with each other, a shearing force is applied to the mixture 5 in the kneading step, and therefore phase separation (particularly macrophase separation) or the like occurs. Although it is sufficiently prevented, the kneaded product 7 after the kneading step is not subjected to shearing force, so if it is left for a long period of time, it may cause phase separation (especially macro phase separation) again. is there. Therefore, it is preferable to cool the kneaded material 7 obtained as described above as soon as possible. Specifically, the cooling rate of the kneaded material 7 (for example, the cooling rate when the kneaded material 7 is cooled to about 60 ° C.) is preferably −3 ° C./second or more, and is preferably −5 to −100 ° C. / More preferably it is seconds. In addition, the time required from the end of the kneading step (when the shearing force is no longer applied) to the completion of the cooling step (for example, the time required for cooling the temperature of the kneaded product 7 to 60 ° C. or less) is 20 seconds. Or less, more preferably 3 to 12 seconds.

In the present embodiment, a configuration in which a continuous biaxial kneading extruder is used as the kneading machine has been described. However, the kneading machine used for kneading the mixture (composition for toner production) is not limited thereto. For the kneading of the mixture, for example, various kneaders such as a kneader, a batch-type triaxial roll, a continuous biaxial roll, a wheel mixer, and a blade type mixer can be used.
In the illustrated configuration, the kneader having two screws has been described. However, the number of screws may be one or three or more.

  Further, in the present embodiment, the configuration using one kneader has been described, but kneading may be performed using two or more kneaders.

Further, in the present embodiment, a configuration using a belt type as the cooler has been described. However, for example, a roll type (cooling roll type) cooler may be used. Further, the cooling of the kneaded product extruded from the extrusion port 32 of the kneader is not limited to the one using the above-described cooler, and may be performed by, for example, air cooling.
By granulating the kneaded material 7 that has undergone the cooling process as described above, a powder for toner production is obtained.
In the present embodiment, the granulation step includes a pulverization step and a thermal spheronization step as described below.

<Crushing process>
First, the kneaded product 7 that has undergone the cooling step as described above is pulverized to obtain a pulverized product.
The method of pulverization is not particularly limited, and can be performed using various pulverizers and crushers such as a ball mill, a vibration mill, a jet mill, a pin mill, and a feather mill.
The pulverization process may be performed in multiple steps (for example, two stages of a coarse pulverization process and a fine pulverization process).
Moreover, you may have the classification process which classifies a ground material after such a grinding | pulverization process. Thereby, the particle size distribution of the toner particles can be sharpened. As a result, it is possible to obtain an optimum toner for forming an image with high resolution and prevention of fogging and the like. A classification process can be performed using a sieve, an airflow classifier, etc., for example.

The classification process (classification process) may be performed simultaneously with the above-described pulverization process (pulverization process).
Moreover, you may use the fine powder generate | occur | produced in the above pulverization processes, classification processes, etc. as a material for mixture preparation mentioned above, for example. Thereby, the recycling efficiency of fine powder is improved, and the yield of toner production is further improved. In addition, this makes the obtained toner particularly excellent in reliability.

<Thermal spheronization process (thermal spheronization process)>
Next, a heat spheronization treatment is performed in which the pulverized product (powder for toner production) obtained as described above is heated to be spheroidized.
By performing such a thermal spheronization treatment, toner (toner particles) having a sufficiently high circularity can be obtained easily and reliably. As a result, the finally obtained toner has a small difference in charging characteristics between the individual toner particles, the developability on the photoreceptor is improved, and the toner adheres to the photoreceptor (filming). ) Is more effectively prevented, and the toner transfer efficiency is further improved. On the other hand, in the manufacture of conventional recycled toner, since a heat insulating layer (air layer) is easily formed around the recycled fine powder, a sufficient effect can be obtained even if such a thermal spheronization treatment is performed. Therefore, it is difficult to obtain a toner (toner particles) having a sufficiently high circularity.

The thermal spheronization treatment can be performed by injecting the toner manufacturing powder (pulverized product) obtained in the pulverization step into a heated atmosphere using, for example, compressed air. At this time, the atmospheric temperature is preferably 210 to 320 ° C, and more preferably 230 to 300 ° C. If the atmospheric temperature is less than the lower limit, it may be difficult to sufficiently increase the circularity. On the other hand, when the ambient temperature exceeds the upper limit, the material is likely to be thermally decomposed, oxidized and deteriorated, and the function of the finally obtained toner may be lowered.
As described above, a powder for toner production can be obtained.
Such a thermal spheronization process may be performed in a liquid.

Further, after such a thermal spheronization step, a classification step for classifying the powder for toner production may be provided. Thereby, the particle size distribution of the toner particles can be sharpened. As a result, it is possible to obtain an optimum toner for forming an image with high resolution and prevention of fogging and the like. A classification process can be performed using a sieve, an airflow classifier, etc., for example.
Moreover, you may use the fine powder obtained by the classification process etc. (sorted) as a material for mixture preparation mentioned above, for example. Thereby, the recycling efficiency of fine powder is improved, and the yield of toner production is further improved. In addition, this makes the obtained toner particularly excellent in reliability.

<External addition process (external addition process)>
Next, the toner is obtained by applying an external additive to the heat-spheroidized toner production powder.
This external addition process (external addition process) can be performed using various mixing apparatuses, such as a Henschel mixer and a super mixer, for example.
Moreover, as an external additive, the material mentioned above can be used, for example.

[toner]
The toner is obtained by the method as described above.
The toner particles obtained as described above have a coating ratio of the external additive (the ratio of the area covered by the external additive to the surface area of the toner particles, and the sphere corresponding to the average particle diameter of the external additive is the average particle diameter of the toner. The calculated covering ratio when a corresponding sphere is covered with six-way fine packing is preferably 100 to 300%, more preferably 120 to 220%. If the coverage of the external additive is less than the lower limit, the effect of the external additive may not be sufficiently exhibited. On the other hand, when the coverage of the external additive exceeds the upper limit, the toner fixability tends to decrease.

  Further, in the toner, substantially all of the external additive may be attached to the toner particles (mother particles), or a part of the external additive may be released from the surface of the toner particles. Good. That is, the toner may contain an external additive released from the toner particles. Thus, when the toner contains an external additive released from the mother particles (hereinafter also referred to as “free external additive”), such a free external additive is, for example, opposite to the toner particles. It can function as a microcarrier that is charged to polarity. When such a free external additive functioning as a microcarrier is contained in the toner, toner particles having a reverse chargeability during development or the like (toner particles that are charged with a polarity opposite to the polarity that the toner particles should originally exhibit when charged) ) Can be effectively prevented and suppressed. As a result, the toner is less likely to cause inconvenience such as so-called fog.

  In addition, the content of the external additive in the toner is preferably 0.5 to 8 wt%, more preferably 1 to 5 wt%, and further preferably 2 to 4 wt%. When the content of the external additive is within such a range, the external additive is sufficiently prevented from being adversely affected by a large amount of the external additive released from the toner base particles (powder for toner production). The function of the additive can be exhibited more effectively.

  The toner (toner particles) obtained as described above preferably has an average circularity R represented by the following formula (I) of 0.91 to 0.98, preferably 0.93 to 0.98. It is more preferable that When the average circularity R is less than 0.91, it becomes difficult to sufficiently reduce the difference in charging characteristics between individual toner particles, and the developability on the photoreceptor tends to be lowered. On the other hand, if the average circularity R is too small, toner adhesion (filming) is likely to occur on the photoreceptor, and the toner transfer efficiency may be reduced. On the other hand, when the average circularity R exceeds 0.98, the transfer efficiency and mechanical strength are increased, but there is a problem that the average particle diameter is increased by promoting granulation (joining of particles). If the average circularity R exceeds 0.98, for example, it becomes difficult to remove the toner adhering to the photoreceptor or the like by cleaning.

R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is a perfect circle having an area equal to the area of the projected image of the toner particles to be measured (completely (Represents the perimeter of a geometric circle)
The average particle diameter of the toner (toner particles) is preferably 5 to 9 μm, more preferably 7 to 8 μm. When the average particle size of the toner is less than the lower limit, fusion between toner particles or the like is likely to occur. On the other hand, when the average particle diameter of the toner exceeds the upper limit value, the resolution of the printed matter tends to decrease.

  Further, the content of the resin (resin component) in the toner (including the resin component derived from fine powder) is preferably 50 to 98 wt%, and more preferably 85 to 97 wt%. If the resin content is less than the lower limit, the function of the resin (for example, good fixability in a wide temperature range) may not be sufficiently obtained. On the other hand, when the content of the resin exceeds the upper limit, the content of components such as a colorant is relatively decreased, and it may be difficult to exhibit characteristics such as color developability.

  The content of the colorant in the toner (including the colorant component derived from fine powder) is not particularly limited, but is preferably 1 to 10 wt%, and more preferably 3 to 8 wt%. If the content of the colorant is less than the lower limit, it may be difficult to form a visible image having a sufficient density depending on the type of the colorant. On the other hand, when the content of the colorant exceeds the upper limit, the content of the resin is relatively lowered, and the fixing property to a transfer material (recording medium) such as paper at a necessary color density is lowered.

  Further, when the toner contains a wax, the content thereof (including fine powder-derived wax) is not particularly limited, but is preferably 5 wt% or less, more preferably 3 wt% or less, and More preferably, it is 5 to 3 wt%. If the content of the wax is too large, the wax is liberated and coarsened, and the exudation of the wax on the toner surface may occur remarkably, making it difficult to sufficiently increase the toner transfer efficiency.

The mixing method, toner manufacturing method, and toner of the present invention have been described based on the preferred embodiments, but the present invention is not limited to this.
For example, the toner of the present invention is not limited to those manufactured by the method described above. For example, in the above-described embodiment, the thermal spheronization process is described as being performed after the pulverization step. However, such a thermal spheronization process may be omitted.

  Further, in the above-described embodiment, it has been described that the toner is obtained by mixing the powder for toner production subjected to the thermal spheronization treatment and the external additive. However, for example, the toner of the present invention is obtained by the pulverization process. The obtained powder for toner production may be obtained by performing an external addition process and then performing a thermal spheronization process. That is, the external addition process may be performed as a pre-process such as a thermal spheronization process. By performing such an external treatment as a pretreatment, the fluidity and dispersibility of the toner particles are improved, and the fusion of the toner due to heat can be more effectively prevented and suppressed. In such a case, an external addition process may be further performed after the thermal spheronization process. Further, the external addition step may be omitted.

  Further, in the above-described embodiment, the configuration using the kneading / pulverizing method has been described as the method for producing the toner using the mixture (composition for toner production). However, the toner of the present invention is a mixing method as described above. There is no particular limitation as long as the composition for toner production obtained by the above is used, and for example, it may be obtained by a spray drying method, a collision pulverization method, a pulse jet method or the like.

In the above-described embodiment, the rutile-anatase type titanium oxide has been described as being added as an external additive. For example, the rutile-anatase-type titanium oxide is used as a component of a raw material that is supplied to the mixing step and the kneading step. By using it, it may be contained in the toner.
In the above-described embodiment, the configuration in which the thermal spheronization process is performed under dry conditions has been described. However, the thermal spheronization process may be performed under wet conditions such as in a solution.

Moreover, although embodiment mentioned above demonstrated the structure which uses a continuous twin-screw extruder as a kneading machine, the kneading machine used for kneading | mixing of a mixture is not limited to this. For the kneading of the mixture, for example, various kneaders such as a kneader, a batch-type triaxial roll, a continuous biaxial roll, a wheel mixer, and a blade type mixer can be used.
In the illustrated configuration, the kneader having two screws has been described. However, the number of screws may be one or three or more.

  In the above-described embodiment, the configuration using the belt type as the cooler has been described. However, for example, a roll type (cooling roll type) cooler may be used. Moreover, the cooling of the kneaded material extruded from the extrusion port of the kneader is not limited to the one using the above-described cooling machine, and may be performed by air cooling or the like, for example.

First, the following components were prepared as materials for preparing the following mixture (composition for toner production).
<Resin component A>
Amorphous polyester resin (manufactured by Sanyo Chemical Industries, Ltd., Hymer ES803, glass transition point: 60 ° C.)
<Resin component B>
Cross-linked polyester resin (manufactured by Sanyo Chemical Industries, glass transition point: 65 ° C)
<Pigment (colorant)>
Quinacridone PR. 122
<Charge control agent>
Chromium salicylate complex (Bontron E-81)
<Wax>
Carnauba wax

  Each of the above components is granular, and the particle size adjusted by classification treatment was used. The average particle diameter of the resin component A (resin granules) is 300 μm, the average particle diameter of the resin component B (resin granules) is 300 μm, the average particle diameter (secondary particle diameter) of the pigment (colorant granules) is 50 μm, The average particle diameter (secondary particle diameter) of the charge control agent (charge control agent granules) was 50 μm, and the average particle diameter of the wax (wax granules) was 800 μm.

[1] Manufacture of toner (reference example)
First, the above resin component A: 80 parts by weight, resin component B: 20 parts by weight, pigment: 5 parts by weight, charge control agent: 1 part by weight, wax: 5 parts by weight, Henschel mixer 20L ( It was put into the mixing tank of Mitsui Mining Co., Ltd.
Then, while flowing warm water (20 ° C.) through the jacket surrounding the mixing tank, the rotary blade (model: ST / A0) of the Henschel mixer was rotated at 2800 rpm (tip peripheral speed: 40 m / s), and each of the above components was The mixture was obtained by mixing and stirring for a minute. The internal temperature (material temperature) during mixing and stirring was 25 ° C. at the maximum.

Next, the mixture obtained as described above was kneaded using a biaxial kneading extruder as shown in FIG.
The total length of the process part of the biaxial kneading extruder was 160 cm.
Moreover, it set so that the temperature of the mixture in a process part might be 65-90 degreeC.
Moreover, the rotational speed of the screw was 120 rpm, and the charging speed of the mixture was 20 kg / hour.
The time required for the mixture to pass through the process part determined from such conditions is about 2 minutes.

The kneaded material obtained by kneading the mixture in the process part was extruded outside the biaxial kneading extruder through the head part. The temperature of the kneaded material in the head part was adjusted to 110 ° C.
Thus, the kneaded material extruded from the extrusion port of the biaxial kneading extruder was cooled using a cooling machine as shown in FIG. The temperature of the kneaded material immediately after the cooling step was about 46 ° C.

The cooling rate of the kneaded product was −7 ° C./second. In addition, the time required from the end of the kneading process to the end of the cooling process was 10 seconds.
The kneaded product cooled as described above was coarsely pulverized (average particle size: 1 to 2 mm), and then finely pulverized. A hammer mill was used for coarse pulverization of the kneaded product, and a jet mill (200 AFG, manufactured by Hosokawa Micron Corporation) was used for fine pulverization. The fine pulverization was performed at a pulverization air pressure: 500 [kPa] and a rotor rotational speed: 7000 [rpm].

The pulverized product thus obtained was classified with an airflow diverter (manufactured by Hosokawa Micron Corporation, 100 ATP).
The fine powder (average particle size: 3 μm) having a particle size of 4 μm or less obtained (classified) by classification was an amount corresponding to 28 wt% of the kneaded product to be subjected to the pulverization step.
Thereafter, the pulverized product having a particle size of 5 to 9 μm (average particle size: 7 μm) was subjected to a thermal spheronization treatment. The thermal spheronization treatment was performed using a thermal spheronization apparatus (Nihon Pneumatic Kogyo Co., Ltd., SFS3 type). The temperature of the atmosphere during the heat spheronization treatment was 270 ° C.

Thereafter, an external additive was applied to the powder subjected to the thermal spheronization treatment to obtain a toner. The application of the external additive was performed by mixing 100 parts by weight of the powder subjected to the thermal spheronization treatment and 2.5 parts by weight of the external additive using a 20 L type Henschel mixer. As external additives, negatively chargeable small particle size silica (average particle size: 12 nm): 1 part by weight, negatively chargeable large particle size silica (average particle size: 40 nm): 0.5 part by weight, rutile anatase A type of titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 0.5 part by weight was used. In addition, as the negatively chargeable silica (negatively chargeable small particle size silica, negatively chargeable large particle size silica), those subjected to surface treatment (hydrophobization treatment) with hexamethyldisilazane were used. In addition, as the rutile-anatase type titanium oxide, the ratio of the rutile-type titanium oxide crystal structure to the anatase-type titanium oxide is 90:10 and absorbs light in the wavelength region of 300 to 350 nm. A thing was used.
The average particle size of the finally obtained toner was 7.1 μm. The obtained toner had an average circularity R of 0.96. Further, the coverage of the external additive in the obtained toner was 160%. Further, the ratio (release rate) of the external additive contained in the toner that was present as a free external additive was 1.5 wt%.

In addition, the ratio (free rate) of what exists as a free external additive among external additives is calculated | required by the method as mentioned above using a particle analyzer (the Yokogawa Electric Corporation make, PT-1000). It was. The release rate of the external additive was measured under an environment of 25 ° C. and 60% RH.
In addition, the circularity was measured in a water dispersion system using a flow type particle image analyzer (manufactured by Sysmex Corporation, FPIA-2000). However, the circularity R is represented by the following formula (I).

R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is the circumference of a perfect circle having an area equal to the area of the projected image of the toner particles to be measured) Represents length)
Further, the average length of the crystals in the toner was obtained from the result of measurement using a transmission electron microscope (TEM).

(Example 1)
First, by using a dry compression granulator (manufactured by Kurimoto Steel Co., Ltd., roller compactor), a plurality of fine powders (particles) are obtained by compressing and combining the fine powders obtained in the classification process of the reference example. A bound conjugate was obtained.
Next, using a feather mill (manufactured by Hosokawa Micron Corporation, FM-1P), the above-mentioned combined body was pulverized, and further passed through a φ3 mm screen to obtain a large particle size product. The obtained large particle size product had a particle size of 500 to 3000 μm (average particle size: 2000 μm).

Next, the above resin component A: 80 parts by weight, resin component B: 20 parts by weight, pigment: 5 parts by weight, charge control agent: 1 part by weight, wax: 5 parts by weight, and large particle size product : 30 parts by weight was charged into a mixing tank of Henschel mixer 20L (Mitsui Mining Co., Ltd.).
Then, while flowing warm water (20 ° C.) through the jacket surrounding the mixing tank, the rotary blade (model: ST / A0) of the Henschel mixer was rotated at 2800 rpm (tip peripheral speed: 40 m / s), and each component was By mixing and stirring for a minute, a mixture (composition for toner production) was obtained. The internal temperature (material temperature) during mixing and stirring was 25 ° C. at the maximum.

Next, the mixture (composition for toner production) obtained as described above was kneaded using a biaxial kneading extruder as shown in FIG.
The total length of the process part of the biaxial kneading extruder was 160 cm.
Moreover, it set so that the temperature of the mixture in a process part might be 65-90 degreeC.
Moreover, the rotational speed of the screw was 120 rpm, and the charging speed of the mixture was 20 kg / hour.

The time required for the mixture to pass through the process part determined from such conditions is about 2 minutes.
The kneaded material obtained by kneading the mixture in the process part was extruded outside the biaxial kneading extruder through the head part. The temperature of the kneaded material in the head part was adjusted to 110 ° C.

Thus, the kneaded material extruded from the extrusion port of the biaxial kneading extruder was cooled using a cooling machine as shown in FIG. The temperature of the kneaded material immediately after the cooling step was about 46 ° C.
The cooling rate of the kneaded product was −7 ° C./second. In addition, the time required from the end of the kneading process to the end of the cooling process was 10 seconds.
The kneaded product cooled as described above was coarsely pulverized (average particle size: 1 to 2 mm), and then finely pulverized. A hammer mill was used for coarse pulverization of the kneaded product, and a jet mill (200 AFG, manufactured by Hosokawa Micron Corporation) was used for fine pulverization. The fine pulverization was performed at a pulverization air pressure: 500 [kPa] and a rotor rotational speed: 7000 [rpm].

The pulverized product thus obtained was classified with an airflow diverter (manufactured by Hosokawa Micron Corporation, 100 ATP).
The fine powder (average particle diameter: 3 μm) having a particle size of 4 μm or less obtained (classified) by classification was an amount corresponding to 29 wt% of the kneaded product to be subjected to the pulverization step.
Thereafter, the pulverized product with a particle size of 7.0 to 7.5 μm (average particle size: 7.2 μm) was subjected to a thermal spheronization treatment. The thermal spheronization treatment was performed using a thermal spheronization apparatus (Nihon Pneumatic Kogyo Co., Ltd., SFS3 type). The temperature of the atmosphere during the heat spheronization treatment was 270 ° C.

Thereafter, an external additive was applied to the powder subjected to the thermal spheronization treatment to obtain a toner. The application of the external additive was performed by mixing 100 parts by weight of the powder subjected to the thermal spheronization treatment and 2.5 parts by weight of the external additive using a 20 L type Henschel mixer. As external additives, negatively chargeable small particle size silica (average particle size: 12 nm): 1 part by weight, negatively chargeable large particle size silica (average particle size: 40 nm): 0.5 part by weight, rutile anatase A type of titanium oxide (substantially spindle shape, average major axis diameter: 30 nm): 0.5 part by weight was used. In addition, as the negatively chargeable silica (negatively chargeable small particle size silica, negatively chargeable large particle size silica), those subjected to surface treatment (hydrophobization treatment) with hexamethyldisilazane were used. In addition, as the rutile-anatase type titanium oxide, the ratio of the rutile-type titanium oxide crystal structure to the anatase-type titanium oxide is 90:10 and absorbs light in the wavelength region of 300 to 350 nm. A thing was used.
The average particle size of the finally obtained toner was 7.2 μm. The obtained toner had an average circularity R of 0.96. Further, the coverage of the external additive in the obtained toner was 160%. Further, the ratio (release rate) of the external additive contained in the toner that was present as a free external additive was 1.3 wt%.

(Example 2)
First, in the same manner as in Example 1, a bonded body in which a plurality of fine powders (particles) were bonded was obtained.
Next, the above conjugate was crushed using a feather mill (manufactured by Hosokawa Micron Corporation, FM-1P), and further passed through a φ1 mm screen to obtain a large particle size product. The obtained large particle size had a particle size of 300 to 1000 μm (average particle size: 700 μm).
Thereafter, a mixture (composition for toner production) and a toner were produced in the same manner as in Example 1 using the large particle size product obtained as described above.

(Example 3)
First, a large particle size product was obtained in the same manner as in Example 1.
Next, 80 parts by weight of the resin component A and 30 parts by weight of a large particle size were charged into a mixing tank of a Henschel mixer 20L (Mitsui Mining Co., Ltd.).
Then, while flowing warm water (20 ° C.) through the jacket surrounding the mixing tank, the rotary blade (model: ST / A0) of the Henschel mixer was rotated at 2800 rpm (tip peripheral speed: 40 m / s), and each of the above components was A first mixture was obtained by mixing and stirring for a minute. The internal temperature (material temperature) during mixing and stirring was 25 ° C. at the maximum.

Next, the above resin component B: 20 parts by weight, pigment: 5 parts by weight, charge control agent: 1 part by weight, wax: 5 parts by weight, and first mixture: 110 parts by weight, Henschel mixer The mixture was put into a 20 L (Mitsui Mine Co., Ltd.) mixing tank.
Then, while flowing warm water (20 ° C.) through the jacket surrounding the mixing tank, the rotary blade (model: ST / A0) of the Henschel mixer was rotated at 2800 rpm (tip peripheral speed: 40 m / s), and each of the above components was A second mixture (composition for toner production) was obtained by mixing and stirring for a minute. The internal temperature (material temperature) during mixing and stirring was 25 ° C. at the maximum.
Next, using the second mixture (composition for toner production) obtained as described above, kneading, extrusion, cooling, pulverization (coarse pulverization, fine pulverization), classification in the same manner as in Example 1 above. Then, the toner was manufactured by performing each process of heat spheronization and external addition.

Example 4
A toner was produced in the same manner as in Example 3 except that the product having the larger particle size was used in the same manner as in Example 2.
(Example 5)
First, a large particle size product was produced by a method having a melting / kneading step for melting / kneading the fine powder obtained in the above Reference Example and a pulverizing step for pulverizing the kneaded product obtained by the melting / kneading step.
The melting and kneading step was performed using a twin-screw kneader (manufactured by Technobel Co., Ltd., KZW-40). The material temperature (fine powder temperature) in the melting / kneading step was 70 to 90 ° C.

The pulverization step was performed using a pulverizer (FM-1 manufactured by Hosokawa Micron Corporation).
The particle size of the large particle size product thus obtained was 500 to 3000 μm (average particle size: 2000 μm).
Thereafter, a mixture (composition for toner production) and a toner were produced in the same manner as in Example 1 using the large particle size product obtained as described above.

(Comparative Example 1)
A toner was produced in the same manner as in Example 1 except that the fine powder obtained in the above Reference Example (fine powder not having a large particle diameter) was used in place of the large particle size product.
(Comparative Example 2)
A toner was manufactured in the same manner as in Comparative Example 1 except that the processing time of the mixing step was 40 minutes.

(Comparative Example 3)
First, 20 parts by weight of the resin component B and 30 parts by weight of fine powder obtained in the classification step of the reference example were charged into a mixing tank of a Henschel mixer 20L (Mitsui Mining Co., Ltd.).
Then, while flowing warm water (20 ° C.) through the jacket surrounding the mixing tank, the rotary blade (model: ST / A0) of the Henschel mixer was rotated at 2800 rpm (tip peripheral speed: 40 m / s), and each of the above components was A first mixture was obtained by mixing and stirring for a minute. The internal temperature (material temperature) during mixing and stirring was 25 ° C. at the maximum.

Next, the above resin component A: 80 parts by weight, pigment: 5 parts by weight, charge control agent: 1 part by weight, wax: 5 parts by weight, first mixture: 50 parts by weight, Henschel mixer It injected | thrown-in in the mixing tank of 20L (made by Mitsui Mining Co., Ltd.).
Then, while flowing warm water (20 ° C.) through the jacket surrounding the mixing tank, the rotary blade (model: ST / A0) of the Henschel mixer was rotated at 2800 rpm (tip peripheral speed: 40 m / s), and each of the above components was A second mixture (composition for toner production) was obtained by mixing and stirring for a minute. The internal temperature (material temperature) during mixing and stirring was 25 ° C. at the maximum.

Next, using the second mixture (composition for toner production) obtained as described above, kneading, extrusion, cooling, pulverization (coarse pulverization, fine pulverization), classification in the same manner as in Example 1 above. Then, the toner was manufactured by performing each process of heat spheronization and external addition.
The toners obtained in the reference examples, examples, and comparative examples were measured for the content of each component. As a result, the resin component content was 90 to 92 wt%, and the pigment content was 3 to 5 wt%. %, And the wax content was 2 to 3 wt%.

In addition, with respect to the reference examples, examples and comparative examples, the particle size of the large particle size and resin particles used in the production of the toner (preparation of the toner production composition), the weight of the kneaded material used in the pulverization step Table 1 summarizes the ratio of fine powder (fine powder with a particle size of 4 μm or less) obtained during the classification step, the average particle size of the toner, the average circularity R, the coverage of the external additive, and the release rate of the external additive. Showed.
In addition, from the observation using a transmission electron microscope (TEM), in the toner of each example (the present invention), each component used for the preparation of the toner production composition is sufficiently compatible and finely dispersed with each other. It was right. On the other hand, in the toners of the respective comparative examples, it was confirmed that the toner particles had a granular material that seems to be derived from the fine powder used as the raw material.

  As is clear from Table 1, in each Example (present invention), the generation rate of fine powder in the pulverization process was low. On the other hand, in each comparative example, the generation rate of fine powder in the pulverization process was high. This is considered to be due to the following reasons. That is, in each example, each component is sufficiently uniformly mixed in the kneaded product, and the fine powder used as a raw material is almost completely compatible with the other components, whereas in the comparative example, the kneaded product is Each component is not sufficiently mixed in the inside, and the fine powder used as a raw material leaves a trace of its shape. This is thought to be because the fine powder separated almost as it was.

[2] Evaluation Each toner obtained as described above was evaluated for charging characteristics and fog.
[2.1] Charging characteristics The toners obtained in the above Reference Examples, Examples and Comparative Examples were refilled into a cartridge of a color laser printer (manufactured by Seiko Epson Corporation: LP-3000C). After that, in the color laser printer, the operation was stopped in the middle of printing, the cartridge was removed, and the charge amount distribution was measured using a powder charge amount distribution measuring device (E-spart analyzer, manufactured by Hosokawa Micron Corporation). From the above, the positive charge amount was determined as the charge amount and the reverse charge amount.
The charge amount was determined for the charge amount after 1K (after printing 1000 sheets).
For reversely chargeable toner, the existence ratio with respect to the total toner amount is obtained. If the existence ratio of the reverse chargeability toner is less than 3 wt%, the existence ratio of the reverse chargeability toner is 3 wt% or more. Is x.

[2.2] Fog The toner obtained in each of the above Examples and Comparative Examples was refilled into a cartridge of a color laser printer (manufactured by Seiko Epson Corporation: LP-3000C), and 5000 sheets were run. For the 4901st to 5000th printed materials, these images were evaluated according to the following four criteria.
A: No fog is observed at all.
○: Fog is hardly recognized.
Δ: Some fogging is observed.
X: Fog is clearly recognized.
These results are summarized in Table 2.

As can be seen from Table 2, the toner of the present invention was excellent in charging characteristics, did not cause fogging, and was able to form a very clear printed pattern.
In contrast, the toner of the comparative example was inferior in charging characteristics, and fogging was remarkable.
Further, toners were produced in the same manner as in Examples 1 to 5 except that the fine powder generated in the classification process of Examples 1 to 5 was used in the process of increasing the particle size. As a result, similar results were obtained. This further improved the yield of toner production.

  Further, as a colorant, instead of quinacridone (PR 122), copper phthalocyanine pigment, Pigment Red 57: 1, C.I. I. A toner was prepared in the same manner as described above except that CI Pigment Yellow 93 and carbon black were used, and each of these toners was evaluated in the same manner as described above. As a result, the same result as described above was obtained.

FIG. 3 is a longitudinal sectional view schematically illustrating an example of the configuration of a kneader and a cooler used in a toner manufacturing method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Kneading machine 2 ... Process part 21 ... Barrel 22, 23 ... Screw 24 ... Fixed member 3 ... Head part 31 ... Internal space 32 ... Extrusion port 33 ... Cross-sectional area gradually decreasing part 4 ... Feeder 5 ... Mixture (composition for toner production) 6 ... Cooling device 61, 62, 63, 64 ... Roll 611, 621, 631, 641 ... Rotating shaft 65, 66 ... Belt 67 ... Ejection section 7 ...... Kneaded material

Claims (22)

A mixing method for obtaining a recycled toner production composition using a granular material mainly composed of a resin component and toner fine powder generated in a toner production process,
Enlarging the fine powder to obtain a large particle size product,
A mixing method comprising: a mixing step of mixing the large particle size product and the granular material to obtain a mixture.   2. The mixing method according to claim 1, wherein the step of increasing the particle size includes a compression / bonding step of compressing / bonding the fine powder to obtain a combined body in which a plurality of the fine powders are bonded.   The mixing method according to claim 2, wherein the compression / bonding step is performed using a dry compression granulator.   The mixing method according to claim 2 or 3, wherein the step of increasing the particle size includes a crushing step of crushing the combined body after the compression / bonding step.   The mixing method according to any one of claims 1 to 4, wherein the step of increasing the particle size includes a melting / kneading step of melting and kneading the fine powder.   The mixing method according to claim 5, wherein a material temperature immediately after the melting and kneading step is 80 to 150 ° C.   The mixing method according to claim 5 or 6, wherein the step of increasing the particle size includes a pulverization step of pulverizing the kneaded product obtained after the melting and kneading step.   The mixing method according to any one of claims 1 to 7, wherein an average particle diameter of the fine powder is 2 to 4 µm.   The mixing method according to claim 1, wherein an average particle size of the large particle size product is 50 to 900 μm.   The mixing method according to claim 1, wherein an average particle diameter of the granular material is 100 to 900 μm. When the average particle diameter of the granular material subjected to the mixing step is D ₁ [μm] and the average particle diameter of the large particle size is D ₂ [μm], 0.4 ≦ D ₁ / D ₂ ≦ The mixing method according to claim 1, wherein the relationship of 2 is satisfied.   The mixing method according to any one of claims 1 to 11, wherein the content of the large particle size in the material to be subjected to the mixing step is 8 to 27 wt%.   The mixing method according to any one of claims 1 to 12, wherein a glass transition point of a resin component constituting the granular body is 48 to 65 ° C.   The mixing method according to any one of claims 1 to 13, wherein the mixing step is performed using a mixing device having rotating blades, and a peripheral speed of the rotating blades is 10 to 100 m / s.   The mixing method according to any one of claims 1 to 14, wherein a processing time of the mixing step is 5 to 30 minutes.   A method for producing a toner, comprising producing a recycled toner using the mixture obtained by the mixing method according to claim 1. After the mixing step,
Kneading the mixture to obtain a kneaded product; and
The method for producing a toner according to claim 16, further comprising a pulverizing step of pulverizing the kneaded product to obtain a pulverized product.   The toner production method according to claim 17, further comprising a classification step after the pulverization step.   The toner manufacturing method according to claim 18, wherein the fine powder removed in the classification step is used in the first mixing step.   The method for producing a toner according to claim 17, further comprising a thermal spheronization step after the pulverization step.   A toner manufactured using the method according to claim 1.   The toner according to claim 21, wherein the toner particles have an average particle diameter of 5 to 9 μm.

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