JPH09106101A - Production of electrostatic latent image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner of a small particle size having excellent cleaning property with a blade and charge controlling property by fixing a charge controlling agent to the surface of pulverized particles, classifying the pulverized particles and then supplying the classified coarse particles again to the pulverizing process. SOLUTION: Aggregates of color resin particles which essentially consist of a binder resin and a coloring agent and are produced by a wet granulating method are mechanically pulverized in a dry state in the presence of a charge controlling agent to fix the charge controlling agent to the surface of the pulverized particles. Then the pulverized particles are classified and the classified coarse particles are again supplied to the pulverizing process. Namely, after the charge controlling agent is fixed to the surface of pulverized particles, the particles are classified to separate coarse particles and then the coarse particles are circulated to be supplied to the pulverizing process. In this method, a preferable mechanical pulverizing machine used to pulverize the aggregates is equipped with a cylindrical container (outer cylinder) 2 having grooves on its inner surface and a cylinder (inner cylinder) 1 having grooves on its outer surface which can freely rotate and is disposed inside of the outer cylinder 2 at a specified distance from the inner surface of the cylinder 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a toner for developing an electrostatic latent image. More specifically, the present invention relates to a method for producing a toner for developing an electrostatic latent image, which is produced by subjecting toner particles to wet granulation, and aggregating and crushing steps.

[0002]

2. Description of the Related Art In recent years, high image quality is required in the field of electrophotographic copying machines, printers and the like. In order to meet this demand, a manufacturing technique of a toner having a small particle size and a narrow particle size distribution has been studied. Conventional toner manufacturing methods include binder resins, colorants,
Further, a so-called pulverization method is used in which desired additives and the like are melt-kneaded, and the kneaded product is pulverized and classified.

However, the toner obtained by this pulverization method is
The particle size distribution of the toner particles is wide, and there are limits to the reduction of the toner diameter in terms of technology and productivity such as yield. As a method more advantageous than the pulverization method in terms of particle size reduction and productivity, a suspension weight for polymerizing the monomer in the dispersed particles by suspending and dispersing a polymerizable monomer, a colorant and a desired additive in an aqueous medium. A method of manufacturing a toner such as a legal method is also known.

According to such a suspension polymerization method, a spherical toner having a small particle size and a narrow particle size distribution can be obtained, but since the toner particles are small and the shape is close to a sphere, the cleaning property by a blade is good. There is a problem that
Specifically, in the step of wiping off the toner remaining on the photoconductor after transfer with a blade, the shape of particles having a particularly small particle size (hereinafter referred to as small size particles) becomes spherical in the particle size distribution, and The toner on the surface may slip through or be left unwiped, or the toner may be fused on the surface of the photoconductor in the gap between the photoconductor and the blade, which adversely affects the next developed image. Further, there is a difficulty in controlling the chargeability of the toner. The reason for this is not clear, but it is considered that impurities such as surfactants and polymerization catalysts remaining on the surface of the toner particles are a factor affecting the charge of the toner.

As a means for solving such a problem, for example, in JP-A-5-333597, an aggregate of particles obtained by a suspension polymerization method is crushed in an open circuit using a mechanical crusher. Manufactures small particle size toner with high irregularity,
A technique of treating the surface of toner particles with a charge control agent at the time of crushing is disclosed. However, in this technique, since the agglomerate passes through only one crushing step by an open circuit, improvement of irregularity is insufficient and blade cleaning property is insufficient.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is intended to form a high-quality image having excellent blade cleaning property and charge controllability while having a small particle size. An object is to provide a method for producing a toner for developing an electrostatic latent image.

It is an object of the present invention to provide a method for producing a toner for developing an electrostatic latent image which is excellent in uniform charging property and can form an image free from fog.

[0008]

That is, the present invention comprises a binder resin and a colorant as main components, and agglomerates of colored resin particles obtained by a wet granulation method in a dry state in the presence of a charge control agent. A static process having a step of fixing a charge control agent on the surface of the crushed particles while mechanically crushing, and a circulating step of classifying the obtained crushed particles and supplying the classified coarse particles to the crushing step again. The present invention relates to a method for manufacturing a toner for developing an electrostatic latent image.

In the production method of the present invention, in the step of crushing aggregated toner particles, after fixing the charge control agent on the surface of the crushed toner particles, the coarse particles are classified, and the classified coarse particles are subjected to the crushing step. It is characterized by circulating supply. As a result, it becomes possible to manufacture a small particle size toner having a high degree of irregularity and a charge control agent fixed on the surface of the toner particle.

In the method according to the present invention, first, granulation is performed by a wet granulation method. Specifically, a colorant and other desired additives are dispersed in a solution in which a binder resin is dissolved, and this dispersion is suspended in a solvent in which the solution is incompatible with the dispersion sphere. After the solvent in the turbid particles is removed, the solvent is removed to obtain a small-sized spherical toner. A suspension method, a colorant, and a monomer solution in which other desired additives are dispersed are mixed in a solvent in which the solution is incompatible. It can be manufactured by a suspension polymerization method in which a spherical toner having a small particle diameter is obtained by polymerizing monomers in a suspended state by dispersing them into spherical particles, an emulsion polymerization method in which monomers are polymerized in micelles, or a seed polymerization method. .

In the case of the suspension polymerization method, a polymerizable monomer capable of forming a resin component as a binder as described below,
Granulation is carried out by suspending a polymerization composition containing a polymerization initiator, a colorant and other additives in a non-solvent medium and polymerizing the suspension.

[0012] In the case of the emulsion polymerization method, the method known as the seed polymerization method is used because the particle size distribution is good but only extremely fine particles can be obtained by the general emulsion polymerization. preferable. That is, a part of the polymerizable monomer and a polymerization initiator are added to an aqueous medium obtained by adding an aqueous medium or an emulsifier, and the mixture is stirred to emulsify, and then the rest of the polymerizable monomer is gradually dropped to obtain fine particles. The particles are used as seeds for polymerization in droplets of a polymerizable monomer containing a colorant and other additives.

In addition, as a wet granulation method including a polymerization process, a soap-free emulsion polymerization method, a microcapsule method (interfacial polymerization method, in-situ polymerization method, etc.), a non-aqueous dispersion polymerization method, etc. are known. . Further, in the case of the suspension method, a colorant and other additives are added to a resin component as a binder as described below, dissolved and dispersed in an organic solvent, and suspended in a non-solvent medium. And granulate.

The weight average particle diameter (hereinafter, referred to as average particle diameter) of the toner particles (hereinafter, referred to as toner base material) thus granulated in the wet method is 2 to 9 μm, preferably 3 to
It is preferably 8 μm. In the production method of the present invention, it is preferable to add the organic or inorganic fine particles to the obtained toner base material after granulating the toner particles in the liquid medium as described above. By adding such particles, agglomerates having a preferable size can be stably obtained, and the fusion-bonding operation can be stably performed. Moreover, the subsequent crushability is significantly improved. Of course, the characteristics of the inorganic and organic fine particles are imparted to the final toner particles.

As the organic or inorganic fine particles in this case, for example, a charge control agent, a fluidizing agent, magnetic particles, an anti-offset agent, a cleaning aid and the like may be used alone or in combination (however, these may be used here. When the additives are arranged in the toner base material, it is not always necessary that all kinds of additives are adhered to the surface of the toner base material as the above-mentioned fine particles, and some of them are mixed with the binder resin and the colorant to form the toner base material. It is also possible to incorporate the same kind of additives into the toner base material and to have the same kind of additives adhere to the surface of the toner base material as fine particles.

The magnetic substance added when preparing the magnetic toner includes magnetite, γ-hematite,
Alternatively, there are various ferrites. As an offset preventive agent used for improving the fixing property of the toner, specifically, various waxes, particularly low molecular weight polypropylene, polyethylene, or polyolefin type waxes such as oxidized polypropylene and polyethylene, and further carnauba wax, etc. Natural wax is preferably used.

As the fluidizing agent, various metal oxides such as silica, aluminum oxide, titanium oxide and magnesium fluoride are used alone or in combination. Examples of the cleaning aid include inorganic fine particles described above as fluidizing agents, metal soaps such as stearates, fluorine-based, silicon-based, styrene- (meth) acrylic-based, benzoguanamine, melamine, and various synthetic resin particles such as epoxy. Used.

The charge control agent is not particularly limited as long as it can give positive or negative charge by frictional charging, and various organic or inorganic charge control agents can be used. For example, as positive charge control agents, nigrosine base EX, Bontron N-01, 02, 04, 05, 07, 09, 1
0 and 13 (all manufactured by Orient Chemical Industry Co., Ltd.), oil black (manufactured by Chuo Synthetic Chemical Industry Co., Ltd.), quaternary ammonium salt P-51 (manufactured by Orient Chemical Industry Co., Ltd.), polyamine compound P-52 (manufactured by Orient Chemical Industry Co., Ltd.). ), Sudan Chief Schwarz BB (Solvent Black 3; C.I.
No. 26150), Fett Schwarz HBN (C.
I. No. 26150), Brilliant Spirits Schwarz TN (manufactured by Farben Fabriken Bayer),
Alkoxylated amines, alkyl amides, molybdic acid chelate pigments, imidazole compounds and the like can be used.

Examples of the negative charge control agent include chromium complex salt type azo dyes S-32, 33, 34, 35, 37, 38 and 40 (manufactured by Orient Chemical Industry Co., Ltd.), Eisenspirone Black TRH, BHH (manufactured by , Hodogaya Chemical Co., Ltd.), Kayaset Black T-22,004 (above, Nippon Kayaku Co., Ltd.), copper phthalocyanine dye S-39 (Orient Chemical Co., Ltd.), chromium complex salt E-81, 82 (above, Orient Chemical Industry Co., Ltd.), zinc complex salt E-84 (Orient Chemical Industry Co., Ltd.), aluminum complex salt E-86
(Manufactured by Orient Chemical Industry Co., Ltd.), boron complex LR-147
(Manufactured by Nippon Carlit Co., Ltd.) and calixarene compounds can be used.

The organic or inorganic fine particles used in the present invention are not limited to those exemplified above, and at least other than these, the organic fine particles include emulsion polymerization method and soap-free emulsion polymerization method. ,
Wet polymerization methods such as non-aqueous dispersion polymerization method, styrene granulated by gas phase method, (meth) acrylic, olefinic, fluorine-containing, nitrogen-containing (meth) acrylic, silicon, benzoguanamine, melamine, etc. Various organic fine particles, and inorganic fine particles include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, diamond carbon random. Various carbides such as boron nitride, titanium nitride, various nitrides such as zirconium nitride, boride such as zirconium boride, iron oxide, chromium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, titanium oxide, alumina, Various oxides such as colloidal silica,
Sulfides such as molybdenum disulfide, fluorides such as carbon fluoride, various metal soaps such as aluminum stearate, calcium stearate, zinc stearate and magnesium stearate, and various non-magnetic inorganic fine particles such as talc and bentonite are used.

Further, it is desirable that the organic or inorganic fine particles have been subjected to a hydrophobizing treatment or a hydrophobic one from the viewpoint of moisture resistance and charge stability of the obtained toner particles. Particularly, those having a hydrophobicity index (MW: methanol wettability) of 5 or more are preferable.

The size of the organic or inorganic fine particles used here is 1 of the average particle diameter of the granulated toner base material.
/ 5 or less, more preferably about 1/1000 to 1/10. That is, the size of such organic or inorganic fine particles is ⅕ of the average particle size of the toner base material.
This is because if it is larger than the above value, it becomes impossible to adhere the organic or inorganic fine particles to the surface of the toner particles with sufficient strength even after the subsequent step of aggregating the toner base material. If too small ones are used, the effect of adding various fine particles cannot be obtained.

The addition amount of such organic or inorganic fine particles depends on the function of the organic or inorganic fine particles used.
Although it depends on the type and the like, 0.01 to 20 parts by weight, preferably 0.01 to 100 parts by weight of the toner base material is used.
10 to 10 parts by weight, more preferably 0.1 to 5 parts by weight. That is, if the addition amount of such organic or inorganic fine particles is less than 0.01 part by weight, the amount of organic or inorganic fine particles adhering to the surface of the toner base material may be insufficient, and these may not function effectively. On the other hand, if the addition amount exceeds 20 parts by weight, organic or inorganic fine particles that cannot adhere to the surface of the toner base material with sufficient strength are generated, and these may be separated from the surface of the toner particle during use. . In particular, when the organic or inorganic fine particles to be added are charge control agents, the addition amount is 0.01 to 5 parts by weight, more preferably 0.1 to 100 parts by weight of the toner particles.
Is preferably 3 to 3 parts by weight, and when the organic or inorganic fine particles are a fluidizing agent, the addition amount thereof is 0.1 to 5 parts by weight, more preferably 100 parts by weight of the toner base material. It is preferably 0.3 to 3 parts by weight.

The fine particles (including the case of the charge control agent) may be added to the toner base material by the following method. That is, (a)
Fine particles are added to a base material mainly composed of binder particles and a colorant in an aqueous medium, and mixed and then agglomerated; (b) A base material is agglomerated in an aqueous medium and the fine particles are added in a dry state;
(C) After the base material is coagulated and dried, the fine particles are added thereto; and (d) the fine particles are added to the granular dry base material. The method (c) is particularly preferable in the method of the present invention.

The addition amount of the above various organic and inorganic fine particles contributes to the shape control of the toner particles. In the case of the above-mentioned method (a), if the addition amount is increased, the shape is controlled to be spherical. If the amount of addition is small, it will be controlled to be non-spherical. Conversely (b)
In the case of the methods of (c) and (c), the amount is controlled to be non-spherical, while the amount is controlled to be non-spherical, while the amount is controlled to be spherical, depending on the resin used.

Upon aggregation of the toner base material, a known aggregating agent, for example, an inorganic acid such as hydrochloric acid, an organic acid such as oxalic acid, a water-soluble metal salt of these acids and an alkaline earth metal, aluminum or the like is used. May be. However, since these aggregating agents may affect the toner performance, their use should be careful.

There are several possible methods for aggregating the toner base material. For example, prior to the drying step, the toner base material and, if desired, the liquid medium in which the organic or inorganic fine particles are dispersed are subjected to a heat treatment (for example, the glass transition temperature of the resin contained in the toner base material (T
g) or higher, and at a temperature not higher than the boiling point of the liquid medium), prior to the drying step, a solution containing a non-aqueous solvent exhibiting solubility or swelling property with respect to the resin is optionally applied to the surface of the organic or inorganic fine particles. There is a method of contacting the adhered toner base material.

The dry toner base material having the organic or inorganic fine particles adhered to the surface thereof as desired is subjected to a heat treatment (above the glass transition temperature (Tg) of the resin contained in the toner base material and below the softening temperature (Tm) + 60 ° C.). Temperature), or the resin component contained in the toner base material dry toner base material having the organic or inorganic fine particles adhered to the surface as desired,
There is a method of contacting with a solution containing a non-aqueous solvent exhibiting solubility or swelling, and then drying again.

Further, either or both of the temperature and the pressure in the drying step are set to be higher than a general drying condition to some extent, or in the drying step, the resin component contained in the toner base material is dissolved or swelled. There is a method of contacting a solution containing the non-aqueous solvent shown with the toner base material. Of course, it is possible to combine some of the processing methods described above.

In the methods (1) to (4), more appropriate cohesiveness can be obtained by storing under a high humidity condition after the drying step.

The size of the agglomerated particles is 10 to 500 μm, preferably 20 to 300 μm, more preferably 20 to 20 μm.
Adjust to 0 μm. If it is larger than 500 μm, the disintegration property is poor, and if it is smaller than 10 μm, it becomes difficult to control the shape.

By performing the aggregating treatment as described above, the surface portion of the toner base material is melted, melted or swelled, and the toner base materials are bonded to each other to cause agglomeration. The irregularity of the toner of the final developer can be changed by controlling the aggregation state. The greater the degree of melting, dissolution, or swelling, the higher the irregularity of the finally obtained toner when the subsequent crushing process is performed under the same conditions. The specific temperature and time are appropriately selected depending on the mode of treatment.

Further, controlling the pressure is also effective for shape control. For example, by treating under reduced pressure, the proportion of spherical particles can be increased.

The binding force between the toner base materials in the agglomerated state depends to some extent on the particle size of the particles. The smaller the particle size, the greater the bonding strength. Therefore, the bonding force of the particles included in the main particle size range (for example, the particle size is about 2 to 8 μm) of the toner base material formed in the wet granulation in mutual bonding is relatively weak, and the small external force causes Even in the state of agglomeration that can be crushed almost from the bonding site, for example, the binding force of the ultrafine powder having a diameter of 1 μm or less to larger particles within the above-mentioned particle size range is sufficiently large. However, even if an external force as described above is applied thereafter, it is unlikely that these ultrafine powders will dissociate again.

When the toner base material or the agglomerates are isolated or separated from the solution, a non-solvent can be used as a precipitant. The non-solvent means a solvent that does not dissolve or disperse the resin of the toner base material. Examples of such a non-solvent include hydrocarbons such as hexane, heptane, octane and petroleum ether, and lower alcohols such as methanol and ethanol.

In the manufacturing method of the present invention, the drying treatment of the toner base material is carried out after the aggregating treatment as described above, at the same time as the aggregating treatment or before the aggregating treatment, such as a hot air dryer, a spray dryer and the like. Can be carried out by using a general drying apparatus such as that used conventionally. For example, in the case of causing aggregation of the toner base material in the drying process,
Medium fluidized drying device (eg, Nara Machinery: MS
Devices such as D) and a wet surface modification device (for example, Dispercoat manufactured by Nisshin Engineering Co., Ltd.) can be preferably used.

In the embodiment of the present invention, the toner base material aggregate is premixed with the charge control agent.

Mixing is performed with a Henschel mixer, a ball mill,
Other known mixing means may be used.

In order to improve the dispersibility of the charge control agent in the toner aggregate, it is preferable to mix a metal oxide such as silica, titanium oxide or aluminum oxide as a dispersion aid with the charge control agent in the aggregate. The metal oxide is preferably hydrophobized with a hydrophobizing agent. The amount of the dispersion aid added is 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the toner aggregate.

The toner aggregates are crushed by a mechanical crusher in a dry state in the presence of a charge control agent.

A preferred mechanical crusher used for disintegrating agglomerates is a cylindrical container (outer cylinder) having a groove on the inner peripheral surface, with a predetermined gap from the inner peripheral surface, and an outer peripheral surface. A rotation-free cylinder (inner cylinder) having grooves on its surface is used. A schematic configuration diagram of such a crusher is shown in FIG.

The freely rotatable cylinder (inner cylinder) (1) has a large number of grooves on the outer peripheral surface in the direction of the rotation axis and is called the rotor (1). The cylindrical container (outer cylinder) (2) is provided with a liner (2) having a large number of grooves on the inner surface in a cut shape in the rotation axis direction. Then, when the rotor (1) rotates at high speed to generate a violent vortex and pressure vibration inside the machine,
The raw material (a mixture of the toner agglomerate and the charge control agent) is sucked together with air from the intake port (3) and is supplied to the crushing chamber by an air flow. Subsequently, due to the impact force of the rotor (1) and the liner (2) and the violent air vortex generated in these gaps, large-sized particles are volume-pulverized, and the small-sized particles are surface-pulverized, The charge control agent is fixed and is discharged together with air from the exhaust port (4). Surface pulverization means that the particle surface is scraped by the peeling action and at the same time the charge control agent and the like are fixed to the particle surface, that is, rearrangement on the particle surface, and such surface pulverization is particularly
When the toner particles are manufactured by a wet method, it has an effect of removing impurities such as a surfactant adhering to the surface.

FIG. 2 shows a sectional view of the rotor and the liner when cut in the direction perpendicular to the extending direction of the groove. In FIG. 2, the groove of the liner has an isosceles triangular cross-sectional shape (FIG. 2 (a)), and the gap H (minimum gap) with respect to the groove of the rotor is 0.2 to 10 mm, preferably 0.3.
They are facing each other at ~ 5 mm. The cross-sectional shape of the groove of the liner is not limited to the above, and may be, for example, a right-angled triangle as shown in FIG. 2 (b), or the rotor may have a blade instead of the groove (see FIG. 2 (c)). )) Can also be used. As the above-mentioned mechanical crusher, kryptron (manufactured by Kawasaki Heavy Industries, Ltd.), turbo mill (manufactured by Turbo Mill Kogyo Co., Ltd.), fine mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) or the like can be used.

Further, the crushing simultaneous charging process of the above-mentioned toner agglomerates is performed by a multi-pass process by a closed circuit.

More specifically, from the toner particles pulverized by the mechanical pulverizer and at the same time, the charge control agent is fixed on the surface of the toner particles, coarse particles having a size not less than twice the average particle diameter of the toner are classified and classified. The particles are circulated by returning them to the mechanical grinder.

As a result, the irregularity of the small-sized particles of the toner in the particle size distribution of the toner becomes high, and the toner having excellent blade cleaning property can be obtained.

As a classifier for classifying the coarse particles in the obtained crushed particles, a coarse powder classifier (MS-O: manufactured by Hosokawa Micron Co., DS-X classifier: manufactured by Nippon Pneumatic Co., Ltd.,
Elbow Jet: manufactured by Nittetsu Mining Co., Ltd.) can be used.

Finally, it is preferable to classify fine particles into the crushed particles obtained above. The classification may be performed with a rotary rotor type classifier having a classification rotor. By such classification, a toner having improved charging property, printing durability (durability), heat resistance, fluidity and environmental property can be obtained.
This is because the charge control agent is strongly immobilized on the toner surface by the effect of the impact force of the classification rotor due to the classification and the free charge control agent is reduced, and the classification efficiency is improved by the dispersion effect of the impact force of the classification rotor. , It is possible to prevent the mixture of ultrafine powder into the toner product side.

As the classifying rotor type classifier as described above, various types such as turbo classifier (manufactured by Nisshin Engineering Co., Ltd.) and AccuCut, for example, Dona Selec classifier (manufactured by Donaldson Japan) are known. Of these, the Teaplex ultrafine powder classifier ATP series (manufactured by Hosokawa Micron) is preferable. A schematic configuration diagram of the Teeplex multi-wheel type classifier in this series is shown in FIG. FIG. 3 is a central vertical sectional view.

The raw material (crushed particles) is fed into the raw material inlet (22).
From a rotary valve as shown in FIG. 3 or with the incoming air into the classification chamber. The inflowing air flows from the bottom to the top in the classifier as indicated by an arrow, for example. In accordance with the flow, the raw material rises, enters the classification section (21) and is classified, and the fine powder is discharged from the common fine powder discharge port (2
3) and the toner particles are taken out from the discharge port (24). The classifying unit (21) has a plurality of classifying rotors horizontally mounted by an individual drive method. As shown in FIG. 4, the classification rotor is a cylindrical rotating body having many blades. Common speed control is done through one frequency converter.

At this time, if the retention amount of the classifier is B%,
When the feed amount of the classification unit is A kg / hr and the amount of recovery after stopping the feeder is C kg, B = (C / A) × 100>
It is preferably about 20. Increasing the retention amount makes the adhesion of the charge control agent to the toner stronger and improves the printing durability of the developer.

The weight average particle diameter of the finally obtained toner is adjusted to 2 to 9 μm, preferably 3 to 8 μm. If the average particle size is larger than 9 μm, it does not meet the purpose of improving the quality of copied images. Further, there is a problem that it is difficult to manufacture a toner having a size smaller than 2 μm, and it becomes difficult to handle it in each element (toner supply, development, transfer, fixing, cleaning) of the image forming apparatus.

The toner constituting the electrostatic latent image developing toner produced by the method of the present invention contains at least a resin as a binder and a colorant in the composition of toner particles, and if desired, The organic or inorganic fine particles are bound to the surface thereof, and are not particularly limited as long as they are bound through the toner aggregation and disintegration steps, such as magnetic or non-magnetic, and charging polarity. Various configurations can be adopted depending on the developing method.

The resin contained in the toner is not particularly limited as long as it is generally used as a binder in toner, and examples thereof include styrene resin, (meth) acrylic resin, and olefin. -Based resins, polyester-based resins, amide-based resins, polycarbonate resins, polyethers, thermoplastic resins such as polysulfone, or thermosetting resins such as epoxy resins, urea resins, urethane resins, and copolymers thereof And polymer blends are used. The binder used in the present invention includes, for example, not only those in a complete polymer state as in a thermoplastic resin but also those in an oligomer or prepolymer state as in a thermosetting resin. In addition, a polymer partially containing a prepolymer, a crosslinking agent, and the like are also included.

The colorant contained in the toner according to the method of the present invention is not particularly limited, and various known organic or inorganic pigments and dyes of various colors can be used. Usually, with respect to 100 parts by weight of the binder resin,
It is desirable to use 1 to 20 parts by weight, more preferably 2 to 10 parts by weight. That is, if the amount is more than 20 parts by weight, the fixing property of the toner is deteriorated, while if the amount is less than 1 part by weight, a desired image density may not be obtained.

The toner of the present invention includes silica, alumina,
It is preferable to externally mix inorganic fine particles such as titania as a fluidizing agent. The fluidizing agent is a silane coupling agent,
From the viewpoint of environmental stability, it is preferable that the surface is hydrophobized with a hydrophobizing agent such as a titanate coupling agent, an aluminum coupling agent, or silicone oil. Also,
In order to adjust the chargeability of the fluidizing agent, a surface treatment may be carried out by using a fluorine-containing silane coupling agent, a fluorine-containing silicone oil, an aminosilane coupling agent, an aminosilicone oil or the like together with the hydrophobizing agent. The fluidizing agent is 0.05 to 3% by weight, preferably 0.1 to 3% by weight based on the toner.
It is desirable to add 1% by weight.

Further, as a cleaning aid, a styrene-based compound which is granulated by a wet polymerization method such as an emulsion polymerization method, a soap-free emulsion polymerization method, a non-aqueous dispersion polymerization method or a gas phase method,
Various resin fine particles such as (meth) acrylic, styrene- (meth) acrylic, olefin, fluorine-containing, nitrogen-containing (meth) acrylic, silicon, benzoguanamine, and melamine are used as toner together with a fluidizing agent. You may add it externally.

The method according to the present invention can be applied to any type of toner constituting a developer, for example, a two-component developer toner mixed with a carrier or a one-component developer. It may be applied to toner.

The toner produced by the method of the present invention is excellent in blade cleaning property, charge stability, fluidity and durability. In the developing method in which a one-component developer is used and the thin layer of toner is regulated, there is an effect that it is easier to control the amount of toner on the sleeve with a blade. Hereinafter, the present invention will be described using examples.

[0060]

EXAMPLE stirrer, inert gas inlet tube, a flask equipped with a reflux condenser and a thermometer, styrene 98 parts by weight of deionized water in 200 parts by weight was dissolved 0.1 part by weight of polyvinyl alcohol A uniform suspension was prepared by adding a mixture of 8 parts by weight of benzoyl peroxide to a polymerizable monomer composed of 2 parts by weight of isopropenyl oxazoline and stirring the mixture at high speed. Then, while introducing nitrogen gas, 80
After heating to ℃ and carrying out the polymerization reaction while stirring for 5 hours,
After cooling, a polymer suspension was obtained. Furthermore, after repeating filtration and washing, it was dried to obtain a polymer having an oxazoline group as a reactive group.

40 parts by weight of the polymer obtained here and 20 parts by weight of carbon black (MA-600: manufactured by Mitsubishi Kasei Co., Ltd.) were kneaded at 170 ° C. using a three-roll mill. After this kneaded product was cooled, it was ground with a feather mill to obtain a carbon black graft polymer.

In a reaction kettle equipped with an inert gas inlet tube, a reflux condenser and a thermometer, styrene prepared in advance in deionized water containing 0.5% by weight of sodium dodecylbenzenesulfonate as an anionic surfactant. 80 parts by weight, a polymerizable monomer component consisting of 20 parts by weight of n-butyl acrylate, 50 parts by weight of a carbon black graft polymer, 3 parts by weight of azobisisobutyronitrile and 2,
A mixture containing 3 parts by weight of 2'-azobisisobutyronitrile was charged, and T. K. An auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) was mixed and stirred to obtain a uniform suspension. Next, blow nitrogen gas to the suspension at 65 ° C.
After heating to 0 ° C., stirring was continued for 5 hours at this temperature to carry out a suspension polymerization reaction, and then heating to 75 ° C. to perform polymerization to obtain spherical particles having an average particle size of 6 μm.

Hydrophobic silica (R-97
4: made by Nippon Aerosil Co., Ltd.) 0.3% by weight based on the solid content
After the addition, stirring was continued while further applying a temperature to treat the surface of the particles with the hydrophobic silica. Then, after repeating filtration (dehydration) and washing with water, a drying device (medium flow drying device M
Dry granulation (aggregation) was performed using DS: Nara Machinery Co., Ltd. to obtain an aggregate of about 300 μm.

With respect to 100 parts by weight of this aggregate, 1.0 calixarene compound (E-90: manufactured by Orient Chemical Co.) was used.
Parts by weight, hydrophobic silica (H-2000: manufactured by Wacker)
0.3 parts by weight was added and mixed with a Henschel mixer for 1 minute at a peripheral speed of 25 m / s. Then, the inlet air temperature was 5 ° C., the exhaust temperature was 30 ° C., and the relative rotation of the outer cylinder and the inner cylinder was performed. Cryptography / surface treatment was performed at 12000 rpm with a Kryptron grinder (KTM-O type: manufactured by Kawasaki Heavy Industries, Ltd.) having a minimum gap of 1 mm.

Thereafter, the obtained product is treated with a coarse powder classifier (MS
-O: Hosokawa Micron Co., Ltd.) was used for coarse powder classification at 3000 rpm, and particles having a particle size of 15 μm or more were returned to the Cryptron grinder. The particles obtained here were finely classified by a turboplex (50 ATP: manufactured by Hosokawa Micron Co., Ltd.) at a rotation speed of 18000 rpm and a rotor peripheral speed of 47.1 m / s to obtain toner particles having an average particle diameter of 7.0 μm. To 100 parts by weight of the toner particles, hydrophobic silica (H-2
000: 0.3 parts by weight of Wacker) and 0.3 parts by weight of hydrophobic titanium oxide (T-805: manufactured by Degussa), and a peripheral speed of 30 m / s with a Henschel mixer (manufactured by Mitsui Miike Kakoki Co., Ltd.). And mixed for 2 minutes to obtain toner a.

Comparative Example After crushing / surface treatment with a Cryptron grinder, the same procedure as in Example was carried out except that coarse powder classification was not carried out and only one crushing / surface treatment step by an open circuit was carried out. Thus, a toner b having an average particle size of 6.9 μm was obtained.

Evaluation Toners a and b thus obtained are mixed with a carrier prepared as described below to obtain toners A and B, respectively.

Acrylic modified silicone resin (KR970
6: Shin-Etsu Chemical Co., Ltd.) 20 parts by weight was dissolved in 400 ml of methyl ethyl ketone to prepare a coating solution.
This coating solution is Spiracoater (Okada Seiko Co., Ltd.)
Was sprayed onto Cu-Zn ferrite particles having an average particle size of 50 μm to coat the resin, and then the coating resin was cured by heating at 180 ° C. for 30 minutes to prepare an acrylic-modified silicone resin-coated carrier. The carrier bulk was taken out, disintegrated with a pulverizer, classified with a 90 μm sieve, and further subjected to magnetic separation to remove low magnetic force components to prepare a resin-coated ferrite carrier having an average particle diameter of 50 μm.
The carrier particle size is the Microtrack model (799
5-10 SRA: manufactured by Nikkiso Co., Ltd., and the values were averaged.

Next, the toners a and b and the carrier are mixed so that the toner content is 4% by weight, and the toner A is mixed.
And B were prepared, and the average particle size, particle size distribution, apparent apparent specific gravity and charge amount of each toner were measured, and a printing durability test was conducted to evaluate fog and blade cleaning properties.

Measurement of Average Particle Size and Particle Size Distribution A relative weight distribution for each particle size of each toner was measured with a 100 μm aperture tube using a Coulter counter (TA-II type: manufactured by Coulter Counter Co.) to determine the average particle size. I asked. The results are shown in Table 1.

Measurement of Loose Apparent Specific Gravity A powder tester (manufactured by Hosokawa Micron Co., Ltd.) was used for measurement and determined as an alternative characteristic of irregularity. The results are shown in Table 1.

Measurement of charge amount The charge amount was measured by using the charge amount measuring device shown in FIG.
This was performed as follows.

The number of rotations of the magnet roll (13) is set to 10
Set to 0 rpm, and measure the developer as a developer after stirring for 3 minutes, 30 minutes and 90 minutes,
The charge rising property and the charge stability were evaluated. 1 g of this developer was weighed with a precision balance and placed uniformly on the entire surface of the conductive sleeve (12). Next, a bias voltage of 3 KV is applied from the bias power source (14) opposite to the charging potential of the toner, the sleeve (12) is rotated for 30 seconds, and the potential Vm when the sleeve (12) is stopped is read. At that time, the weight Mi of the separated toner (15) attached to the cylindrical electrode (11) was measured by a precision balance to obtain the average toner charge amount. The above measurement was performed at a temperature of 20 ° C. and a humidity of 65.
% Environment. The results are shown in Table 1.

Printing endurance test Using toners A and B, 5 with a printer CF-70 (manufactured by Minolta Co., Ltd.) in an environment of temperature 20 ° C. and humidity 65%
000 copies are made, initial, 2000 and 5000
The image after printing one sheet was evaluated for fog and blade cleaning property. Each ranking was performed as follows.

Fog ○: None △: Slightly recognized but practically no problem ×: Practical problem

Blade Cleaning Property ◯: Good Δ: Not good, but practically no problem X: Practically problematic The above evaluation results are shown together with the above measurement results in Table 1 below.

[Table 1]

Although the loose apparent specific gravity of the toner A according to the present invention can be said to be an appropriate value, it is lower than that of the toner B. This means that the irregularity of Toner A increased due to the closed circuit crushing / surface treatment process.
Considering also that the blade cleaning property after printing 000 sheets is good, it is considered that the irregularity of the small-diameter particles is increased and the slip-through is prevented. Further, the toner A has stable chargeability, and has good image characteristics, especially fog.

[0078]

According to the method for producing a toner of the present invention, it is possible to obtain a toner having excellent blade cleaning property and uniform charging property, capable of forming a high-quality image without fog and having printing durability.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a mechanical crusher.

2A, 2B, and 2C are views for explaining a configuration of a rotor and a liner in a mechanical crusher.

FIG. 3 is a central vertical sectional view of a classifying rotor type classifier.

FIG. 4 is a schematic configuration diagram of a classification rotor.

FIG. 5 is a schematic configuration diagram of a charge amount measuring device.

[Explanation of symbols]

1: rotor, 2: liner, 3: intake port, 4: exhaust port, 11: cylindrical electrode, 12: sleeve, 13: magnet roll, 14: bias power supply, 15: separated toner, 2
1: Classification part, 22: Raw material inlet, 23: Fine powder outlet, 2
4: Toner outlet, 25: Blade

Claims (1)

[Claims] 1. A crushing process, which comprises a binder resin and a colorant as main components, and mechanically crushes aggregates of colored resin particles obtained by a wet granulation method in the presence of a charge control agent in a dry state. Method for producing electrostatic latent image developing toner having a step of fixing a charge control agent on the particle surface, and a circulation step of classifying the obtained crushed particles and supplying the classified coarse particles to the crushing step again .