JP3292000B2 - Toner for developing electrostatic latent images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for developing an electrostatic latent image.

[0002]

2. Description of the Related Art In recent years, high image quality has been demanded in the fields of electrophotographic copying machines and printers. In order to satisfy this demand, the particle size of the toner has been reduced.

[0003] However, when the particle size of the toner is reduced, the specific surface area of the toner increases, and the fluidity of the toner deteriorates.
From the viewpoint of improving fluidity, it is effective to make the toner spherical in order to reduce the specific surface area of the toner.

[0004] The spherical toner is generally produced by a wet granulation method such as a suspension polymerization method. Although this method is effective for reducing the diameter of toner particles, most of the obtained toner particles are spherical. Therefore, in the blade cleaning step, the toner particles are easily rubbed off the blade, and cleaning failure is likely to occur. More specifically, in the process of wiping off toner particles remaining on the photoreceptor after transfer with a blade, the particles having a particularly small particle size (hereinafter, referred to as “small particles”) become spherical in the particle size distribution. The toner on the body surface may be rubbed off or left unwiped, or the toner may be fused on the surface of the photoconductor in the gap between the photoconductor and the blade, adversely affecting the next developed image.

[0005] On the other hand, poor cleaning can be improved by making the shape irregular from the viewpoint of toner shape. Amorphous toners are generally manufactured by a kneading and pulverizing method. However, most of the manufactured toners are amorphous and have a problem that the specific surface area is large and the fluidity is poor. The fluidity of the amorphous toner can be improved by increasing the amount of a fluidizing agent such as silica, but in this case, the environment resistance is deteriorated, the generation of low-charged toner is caused, and the fog is reduced. Problems such as occurrence occur.

As means for solving such a problem, for example, Japanese Patent Application Laid-Open No. 7-49585 discloses a toner in which spherical particles and irregular particles are mixed at a fixed ratio. Here, the above problem is simultaneously solved by improving the fluidity by the spherical particles and the cleaning property by the irregular particles. However,
In such a toner, the spherical particles are contained in a relatively large amount in the small-diameter particles, and the above-mentioned problem of the blade cleaning property cannot be sufficiently solved.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a high degree of irregularity of small-diameter particles, excellent blade cleaning properties, can form a high-quality image, and has fluidity and durability. It is an object of the present invention to provide a toner for developing an electrostatic latent image having a small particle size and excellent in toner properties.

Another object of the present invention is to provide an electrostatic latent image developing toner in which a charge control agent is securely adhered and fixed to the surface of toner particles, is excellent in uniform chargeability, and can form an image without fog or the like. With the goal.

[0009]

That is, the present invention relates to a toner for developing an electrostatic latent image comprising at least a binder resin and a colorant, wherein the number average particle size is 2 to 9 μm and the number average particle size is １ ／ or less. The content of particle size particles is 2 to 10% by number, and the content of particle size
%, The average shape factor represented by the following formula, and the average shape factor (SF ₁ ) of the particles having a particle diameter of ／ or less of the number average particle diameter is the average of the particle diameters having the number average particle diameter or more. The toner for developing an electrostatic latent image, which is larger than the shape factor (SF ₂ ):

(Equation 2) About.

The toner constituting the toner for developing an electrostatic latent image according to the present invention contains at least a resin as a binder and a colorant in the composition of the toner particles. And various configurations can be taken according to the developing method such as magnetic or non-magnetic, and charged polarity.

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

The colorant contained in the toner of the present invention is not particularly limited, and known organic and inorganic pigments and dyes of various colors can be used. Normal,
It is desirable to use 1 to 20 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the binder resin. That is, if the amount is more than 20 parts by weight, the fixability of the toner is reduced, 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 has a number average particle size (hereinafter, referred to as a number average particle size).
2-9 μm, preferably 3-8 μm
It is adjusted to. If the average particle size is larger than 9 μm, it does not meet the purpose of improving the quality of a copied image. Further, it is difficult to manufacture a toner smaller than 2 μm, and there is a problem that it is difficult to handle each element (toner replenishment, development, transfer, fixing, and cleaning) of the image forming apparatus.

Further, in the toner of the present invention, the content of particles having a particle diameter equal to or less than 1/2 of the average particle diameter is 2 to 10% by number,
Preferably, the content of particles having a particle size of 2 to 8% by number and twice or more the average particle size is 1% by number or less, preferably 0.5% by number or less. If the content of particles having a particle diameter equal to or less than の of the average particle diameter is less than 2% by number, the production becomes difficult and causes a cost increase. It causes a spent to etc. If the content of the particles having a particle diameter more than twice the average particle diameter exceeds 1% by number, the purpose of improving the quality of a copied image is not met.

The average particle size in the present invention was measured and measured with a Coulter Multisizer.

Further, regarding the particle shape of the toner of the present invention, the average shape factor (SF ₁ ) of particles having a particle size of ／ or less of the average particle size is determined by the average shape factor of particles having a particle size of not less than the average particle size. (SF ₂ ). Further, it is desirable that SF ₁ is larger than SF ₂ by 8 or more, preferably 12 or more.

The average shape factors (SF ₁ and SF ₂ )
The following (Equation 1):

(Equation 3) (Where the area is the projected area of the powder and the maximum length is the maximum length in the projected image of the powder) and expresses the difference (distortion) between the major axis and the minor axis of the toner. , And if it is a perfect sphere, SF = 100.

That is, in the toner of the present invention, particles having a particle diameter of 2/3 or less of the number average particle diameter (hereinafter, referred to as small particles) are larger than particles having a number average particle diameter or more (hereinafter, referred to as large particles). It can be said that the degree of irregularity is high. As a result, it is possible to prevent the toner particles from slipping through during blade cleaning, and to prevent the image quality of the copied image from deteriorating.

If the irregularity of the small particles is lower than the irregularity of the large particles, in the step of wiping off the toner particles remaining on the photoreceptor after transfer with a blade, the small particles having a nearly spherical shape in the particle size distribution are used. Rubs off the photoreceptor surface,
The blade may be left unwiped, or the toner may be fused on the surface of the photoconductor in the gap between the photoconductor and the blade, thereby adversely affecting the next developed image. The fluidity of the toner can be improved by making the average shape factor of the large particles smaller than that of the small particles, that is, by making the large particles more spherical than the small particles.

Preferably, SF ₁ is between 120 and 160 and SF ₂ is between 100 and 140. If SF ₁ is smaller than 120, the blade cleaning property becomes a problem,
When it is larger than 0, the fluidity of the toner is reduced, and accordingly, the toner replenishing property and the mixing property with the carrier are reduced. Also,
If SF ₂ is greater than 140, the fluidity of the toner will decrease,
It adversely affects the developed image.

The above average shape factor is used as a factor expressing a form such as a powder shape and is measured by an image analyzer (Luzex 5000, manufactured by Nippon Regulator Co., Ltd.). Specifically, the surface image of the toner particles is input to an image analyzer using a scanning electron microscope photograph, and the SF value is calculated. However, the measured value of the shape factor SF is not limited, since there is no significant difference between the models.

The toner particles according to the present invention can be produced by various methods, but a method capable of efficiently producing toner particles having a small particle diameter is preferred. Here, as one embodiment of the present invention, a manufacturing method using a wet granulation method, which is generally used, will be described.

Specifically, a colorant and other desired additives are dispersed in a binder resin solution, and this dispersion is
This solution is suspended in a solvent in which the solution is incompatible to form a sphere, the solvent in the dispersed suspended particles is removed, and then the solvent is removed to obtain a small particle spherical toner. The monomer solution in which the additive is dispersed is suspended in a solvent in which the solution is incompatible to form a sphere, and the monomer is polymerized in a suspension state to obtain a small particle spherical toner. Emulsion polymerization for polymerizing monomers,
Further, it can be produced by a seed polymerization method.

In the case of the suspension polymerization method, a polymerizable composition containing a polymerizable monomer, a polymerization initiator, a coloring agent and other additives capable of forming a resin component as a binder as described above is used. Granulation is performed by suspending in a solvent-based medium and polymerizing.

In the case of the emulsion polymerization method, the particle size distribution is good but only very fine particles can be obtained by general emulsion polymerization. Therefore, a method known as a seed polymerization method is used. preferable.

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, and the like are known. . In the case of the suspension method, a coloring agent and other additives are mixed with the resin component as a binder as described above, dissolved and dispersed in an organic solvent, and this is suspended in a non-solvent medium. And granulate.

The average particle size of the toner particles (hereinafter, referred to as toner base material) wet-granulated in this manner is 2 to 9 μm.
m, preferably 3 to 8 μm. In such a production method, it is preferable that after the toner particles are granulated in the liquid medium, organic or inorganic fine particles are added to the obtained toner base material.
By adding such particles, an aggregate having a preferable size can be stably obtained, and the fusion operation can be stably performed. In addition, the subsequent crushability is significantly improved. Of course, the properties 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 offset preventing agent, a cleaning aid, etc. may be used alone or in combination. When the additives are provided in the toner base material, it is not always necessary that all types of additives are adhered to the surface of the toner base material as the above-mentioned fine particles, and some of them are blended with the binder resin and the colorant to form the toner base material. It is also possible to incorporate the same type of additive in the toner base material and to make it exist as fine particles on the surface of the toner base material.)

The magnetic substance added when preparing the magnetic toner includes magnetite, γ-hematite,
Alternatively, there are various ferrites. As an anti-offset agent used for improving the fixing property of the toner, specifically, various waxes, especially low molecular weight polypropylene, polyethylene, or oxidized polypropylene, polyolefin-based wax such as polyethylene, and further carnauba wax and the like 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 the above-mentioned inorganic fine particles as a fluidizing agent, metal soaps such as stearates, fluorine-based, silicon-based, styrene- (meth) acryl-based, benzoguanamine, melamine, and various synthetic resin fine particles such as epoxy. Used.

The charge control agent is not particularly limited as long as it can give a positive or negative charge by triboelectric charging, and various organic or inorganic charge control agents can be used. For example, as the positive charge control agent, 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 (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), Fettschwarz HBN (C.I.
I. No. 26150), Brilliant Spirits Schwarz TN (manufactured by Farben Fabriken Bayer),
Alkoxylated amines, alkylamides, molybdate chelate pigments, imidazole compounds and the like can be used.

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

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

The organic or inorganic fine particles preferably have been subjected to a hydrophobic treatment or are hydrophobic, from the viewpoints 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 herein may be 1 to the average particle size 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 1/5 of the average particle size of the toner base material.
If the particle size is larger than that, it becomes impossible to adhere the organic or inorganic fine particles to the surface of the toner particles with sufficient strength even after the step of coagulating the toner base material. Also, if the particles are too small, the effect of adding various fine particles cannot be obtained.

The amount of the organic or inorganic fine particles to be added depends on the function of the organic or inorganic fine particles used,
Although it depends on the kind and the like, it is 0.01 to 20 parts by weight, preferably 0.01 to 100 parts by weight based on 100 parts by weight of the toner base material.
10 to 10 parts by weight, more preferably 0.1 to 5 parts by weight. That is, if the amount of the organic or inorganic fine particles is less than 0.01 part by weight, the amount of the organic or inorganic fine particles adhering to the surface of the toner base material becomes insufficient, and they may not function effectively. . On the other hand, when the addition amount exceeds 20 parts by weight, organic or inorganic fine particles which 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 particles during use. . In particular, when the organic or inorganic fine particles to be added are a charge control agent, the amount of addition is 0.01 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner particles.
To 3 parts by weight, and when the organic or inorganic fine particles are a fluidizing agent, the amount of addition is 0.1 to 5 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the toner base material. Desirably, it is 0.3 to 3 parts by weight.

The method for adding the fine particles is as follows: (a) a method of mixing a base material and organic or inorganic fine particles in a wet method and then aggregating the material; A method in which fine particles are added and dried, and (c) a method in which a base material is coagulated and dried to form a block, and then organic or inorganic fine particles are added and mixed, and further crushed are adopted. As another method, an embodiment in which organic or inorganic fine particles are added after the wet granulation is dried (powder-powder mixing) may be adopted. A particularly preferred method for producing the toner of the present invention is (c).

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

For coagulation of the toner base material, a known coagulant, for example, an inorganic acid such as hydrochloric acid, an organic acid such as oxalic acid, or a water-soluble metal salt composed of these acids and an alkaline earth metal or aluminum is used. You may. However, these coagulants may affect the toner performance, so care must be taken when using them.

As other methods for aggregating the toner base material, several modes can be considered. For example, prior to the drying step, the toner base material and, if desired, a liquid medium in which the organic or inorganic fine particles are dispersed are subjected to heat treatment (for example, the glass transition temperature (T
g) or more, and a temperature not higher than the boiling point of the liquid medium), prior to the drying step, a solution containing a non-aqueous solvent showing solubility or swelling with respect to the resin, the organic or inorganic fine particles on the surface as desired. For example, there is a method of contacting the adhered toner base material.

The dried toner base material having the organic or inorganic fine particles adhered to the surface thereof as desired is subjected to a heat treatment (at a temperature not lower than the glass transition temperature (Tg) of the resin contained in the toner base material and not higher than the softening temperature (Tm) + 60 ° C.). Temperature), or the dry toner base material having the organic or inorganic fine particles adhered to the surface thereof as desired with respect to the resin component contained in the toner base material,
There is a method of contacting with a solution containing a non-aqueous solvent showing solubility or swelling, and then drying the solution again.

Further, one or both of the temperature and the pressure in the drying step are set to be somewhat higher than the general drying conditions, or in the drying step, the solubility or swelling property of the resin component contained in the toner base material is reduced. For example, there is a method in which a solution containing the nonaqueous solvent shown is brought into contact with a toner base material. Of course, some of the processing methods described above can be combined.

In the above methods, a more appropriate cohesiveness can be obtained by storing under a high humidity condition after the drying step.

The size of the aggregated 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 crushability is deteriorated, and if it is smaller than 10 μm, control of the shape becomes difficult.

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

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

The bonding force between the toner base materials in the aggregated state depends to some extent on the particle size of the particles. The binding force tends to increase as the particle size decreases. Therefore, the bonding force in the mutual bonding 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 is relatively weak, and the bonding force is small due to a small external force. Even in an agglomerated state that can be disintegrated from the almost joined portion, for example, the bonding force of the ultrafine powder having a diameter of 1 μm or less to larger particles within the above-described particle size range is sufficiently large. Then, even if the above-mentioned external force is applied thereafter, there is little possibility that these ultrafine powders are dissociated again.

When isolating or separating the toner base material or aggregate from the solution, a non-solvent can be used as a precipitant. The non-solvent is 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 toner of the present invention, the drying process of the toner base material is performed after the coagulation process as described above, simultaneously with the coagulation process, or before the coagulation process. It can be performed using a general drying device as conventionally used. For example, when agglomeration of the toner base material is caused in the drying step, a medium fluidized drying apparatus (for example, MSD manufactured by Nara Machine Co.,
Wet surface modification device (for example, manufactured by Nisshin Engineering Co., Ltd .:
A device such as a disper coat) can be suitably used.

In crushing the toner base material aggregate obtained as described above, the charge control agent is fixed together with the charge control agent to fix the charge control agent to the toner particles in order to improve the charge controllability of the toner. It is preferable to perform a crushing treatment. That is, the toner aggregate is subjected to a crushing process by a mechanical crusher in a dry state in the presence of the charge control agent.

When the charge control agent is added, it is more preferable to mix the toner aggregate and the charge control agent in advance. Mixing may be performed using a Henschel mixer, a ball mill, or other known mixing means.

In order to improve the dispersibility of the charge control agent in the toner aggregate, a metal oxide such as silica, titanium oxide or aluminum oxide may be mixed with the charge aggregate as a dispersing aid together with the charge control agent. Preferably, the metal oxide is hydrophobized by a hydrophobizing agent. The addition amount of the dispersing aid 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.

A preferred mechanical pulverizer used for crushing agglomerates has a predetermined gap from the inner peripheral surface inside a cylindrical container (outer cylindrical body) having a groove on the inner peripheral surface, and has an outer peripheral surface. A rotatable cylinder (inner cylinder) having a groove therein is used. FIG. 1 shows a schematic configuration diagram of such a crusher.

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 a 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 direction of the rotation axis. When the rotor (1) rotates at a high speed to generate a strong vortex and pressure vibration inside the machine,
The raw material (a mixture of the toner aggregate and the charge control agent) is sucked together with the air from the intake port (3), and supplied to the pulverizing chamber by an air flow. Subsequently, the impact force of the rotor (1) and the liner (2) and the strong eddy current of air generated in these gaps cause the large-sized particles to be volume-crushed, and the small-sized particles to be surface-pulverized. The charge control agent is fixed, and is discharged together with air from the exhaust port (4). Surface pulverization means that the charge control agent and the like are fixed to the toner particle surface at the same time as the particle surface is scraped off by the peeling action, that is, rearrangement on the particle surface. When manufactured using the method, it has an effect of removing impurities such as a surfactant attached to the surface.

FIG. 2 is a cross-sectional view of the rotor and the liner taken along a direction perpendicular to the direction in which the grooves extend. In FIG. 2, the groove of the liner has an isosceles triangular cross section (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 face each other so as to be about 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), and the rotor may have a configuration in which a blade is disposed instead of the groove (FIG. 2 (c)). )) Can also be used. As the above-mentioned mechanical pulverizer, Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.), turbo mill (manufactured by Turbo Mill Industries, Ltd.), fine mill (manufactured by Nippon Pneumatic Industries, Ltd.) and the like can be used.

In addition, the above-described simultaneous charging processing of crushing of the toner aggregates is performed by a plurality of pass processing using a closed circuit.

The multi-pass processing by the closed circuit means that the charge control agent is pulverized (pulverized) by the above-mentioned mechanical pulverizer, and at the same time, the charge control agent is more than twice the average particle diameter of the toner particles fixed on the toner particle surface. The coarse particles are classified, and the classified coarse particles are returned to the mechanical pulverizer and circulated.

As a result, the irregularity of the small-sized toner particles in the particle size distribution of the toner is increased, and the toner of the present invention having excellent blade cleaning properties is obtained.

As a classifier for classifying coarse particles in the obtained crushed particles, coarse powder classifiers (MS-O: manufactured by Hosokawa Micron Corporation, DS-X: manufactured by Nippon Pneumatic Industries, Ltd., Elbow Jet: Nippon Steel Corporation) And the like can be used.

Finally, it is preferable to classify the crushed particles obtained above into fine powder. Classification may be performed by a rotary rotor classifier having a classification rotor. By such classification, a toner having improved chargeability, printing durability (durability), heat resistance, fluidity and environmental properties can be obtained.
This is because the charge control agent is strongly fixed to the toner surface by the action of the impact force of the classifying rotor and the free charge control agent is reduced, and the classifying efficiency is improved by the dispersion effect of the classifying rotor by the impact force. This is because it is possible to prevent ultra-fine powder from entering the product.

Various kinds of classifying rotor type classifiers such as a turbo classifier (manufactured by Nisshin Engineering Co., Ltd.) and Accucut, for example, a Dona Selec classifier (manufactured by Nippon Donaldson Co., Ltd.) are known. Among these, the TIPLEX ultrafine powder classifier ATP series (manufactured by Hosokawa Micron Corporation) is preferred. FIG. 3 shows a schematic configuration diagram of a teeplex multi-wheel classifier in this series. FIG. 3 is a central vertical sectional view.

The raw material (crushed particles) is supplied to the raw material input port (22).
And is conveyed into the classification chamber via a rotary valve as shown in FIG. 3 or together with the incoming air. The inflowing air flows in the classifier from bottom to top as indicated by arrows. According to the flow, the raw material rises, enters the classification section (21), is classified, and the fine powder is discharged into the common fine powder outlet (2).
3), and the toner particles are taken out from the outlet (24). The classifying section (21) is provided with a plurality of classifying rotors that are individually driven and horizontally mounted. As shown in FIG. 4, the classifying rotor is a cylindrical rotating body having many blades. Common speed control is performed through one frequency converter.

At this time, assuming that the staying amount of the classifier is B%,
B = (C / A) × 100> When the feed amount of the classifying unit is A kg / hr and the amount of collection after stopping the feeder is C kg
It is preferred to be about 20. Increasing the retention amount makes the charge control agent more firmly attached to the toner and improves the printing durability of the developer.

It is preferable that inorganic fine particles such as silica, alumina and titania are externally added and mixed as a fluidizing agent to the toner obtained as described above. The fluidizing agent is preferably hydrophobized by a hydrophobizing agent such as a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, or silicone oil from the viewpoint of environmental stability. In addition, a fluorine-containing silane coupling agent, a fluorine-containing silicone oil, an aminosilane coupling agent together with the hydrophobizing agent to adjust the chargeability of the fluidizing agent,
Surface treatment may be performed using amino silicone oil or the like. The fluidizing agent is added in an amount of 0.05 to 3% by weight, preferably 0.1 to 1% by weight, based on the toner.

As a cleaning aid, styrene-based granules obtained 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;
(Meth) acrylic, styrene- (meth) acrylic, olefinic, fluorine-containing, nitrogen-containing (meth) acrylic, silicone, benzoguanamine, melamine, etc. It may be added externally.

The toner of the present invention manufactured as described above can be applied to any type of toner constituting a developer, and may be applied to, for example, a two-component developer mixed with a carrier. And a one-component developer.

The toner according to the present invention has excellent blade cleaning properties, fluidity, charge stability, and durability. In a developing system in which a one-component developer is used to control the toner thin layer, there is an effect that the amount of toner on the sleeve with the blade can be easily controlled. Hereinafter, the present invention will be described using examples.

[0068]

EXAMPLES Examples 1 to 3 (Production Examples of Toners A to C) Component parts by weight Styrene 60 n-butyl methacrylate 35 methacrylic acid 5 2,2-azobis- (2,4-dimethylvaleronitrile) 0.5 low Molecular weight polypropylene 3 (Viscole 605P; manufactured by Sanyo Chemical Industries, Ltd.) Carbon black (MA # 8; manufactured by Mitsubishi Chemical Industries, Ltd.) 8

The above materials were mixed with a sand stirrer to prepare a polymerization composition. This polymerization composition was stirred in a 3% aqueous gum arabic solution using a stirrer TK Auto Homomixer.
The polymerization reaction was carried out at a temperature of 60 ° C. for 6 hours while stirring at 3500 rpm using (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a toner dispersion system in which spherical particles having an average particle size of 6.7 μm were dispersed.

Separately, fluorinated alkyl methacrylate resin dispersion and hydrophobic titanium oxide
(T-805; manufactured by Nippon Aerosil Co., Ltd.) is previously dispersed in an aqueous medium at a solid weight ratio of 5: 3 using a sand mill (paint conditioner; manufactured by Red Devil Co.).

The obtained mixture of fluorinated alkyl methacrylate resin / titanium oxide was added to the above toner dispersion at a solid content of 0.8 part by weight based on 100 parts by weight of the solid content of the toner. The surface of the toner particles was treated with a mixture of fluorinated alkyl methacrylate resin / titanium oxide. Thereafter, filtration / washing was repeatedly performed, and the dispersion was dried using a drying apparatus (medium fluidized drying apparatus MSD-).
200 type; Nara Machinery Co., Ltd.), hot air temperature: 85
C., air flow rate: 10 m ³ / min, processing amount: 5 kg / hour, exhaust temperature: 62 ° C. As a result of dry granulation, the particles are aggregated and melted in a state where the fine particles are present at the interface, and the block shape is obtained. I got something.

The temperature of the inlet air was set at 10 ° C., the temperature of the exhaust air was set at 28 ° C., the processing section was set at 10 ° C., and the jacket was cooled, and the minimum gap between the fixed outer cylinder and the rotatable inner cylinder was set at 5 mm. Kryptron system (Kawasaki Heavy Industries, Ltd.)
After performing crushing / surface modification treatment at 18,000 rpm using a KTM-XL type), particles having a particle size of 15 μm or more are coarsely classified by a coarse particle classifier (DSX: manufactured by Nippon Pneumatic). The coarse particles were returned to the kryptron grinder again. The fine particles of the particles obtained here were classified by TIPLEX 50ATP (manufactured by Hosokawa Micron) to obtain crushed particles having an average particle size of 4.1, 6.2 and 8.0 μm, respectively.

For 100 parts by weight of each of the obtained crushed particles, 0.2 parts by weight of hydrophobic silica was used for the crushed particles having an average particle size of 4.1 and 6.2 μm (R-974: Nippon Aerosil Co., Ltd.). And 0.4 parts by weight of hydrophobic titanium oxide (STT30A: manufactured by Titanium Industry Co., Ltd.)
For the crushed particles having an average particle size of 8.0 μm, 0.2 parts by weight of the same hydrophobic silica and 0.3 parts by weight of the same hydrophobic titanium oxide were added, and a Henschel mixer (manufactured by Mitsui Miike Kakoki Co., Ltd.)
At 2,000 rpm for 1 minute to obtain toners A, B and C.

Example 4 (Production Example of Toner D) Production Method of Fine Particles 0.4 g of ammonium persulfate was dissolved in 800 g of ion-exchanged water and transferred to a four-necked flask. While the inside of the flask was replaced with nitrogen, the mixture was heated to 75 ° C., a solution of 160 g of styrene and 40 g of butyl acrylate was added, and the mixture was polymerized at a stirring speed of 400 rpm for 6 hours.
A solution in which uniform particles of μm and a glass transition temperature of 70 ° C. were dispersed was obtained. Disperse the dispersion solution
(Nisshin Engineering Co., Ltd.) and dried to obtain fine particles a.

Method for Producing Toner Particles 100 g of a polyester resin (NE-382; manufactured by Kao Corporation) was dissolved in 400 g of a mixed solvent of methylene chloride / toluene (8/2), and 5 g of a phthalocyanine pigment was placed in a ball mill.
The mixture was mixed and dispersed for 3 hours to obtain a uniform dispersion.

Next, 60 g of a 4% solution of methylcellulose (Methocel K35LV; manufactured by Dow Chemical Co.) as a dispersion stabilizer and 1% of dioctyl sulfosuccinate soda (Nicol OTP75; manufactured by Nikko Chemical Co.) as a dispersion stabilizer.
5 g of the solution, sodium hexametaphosphate (manufactured by Wako Pure Chemical Industries, Ltd.)
5 g was poured into an aqueous solution in which 1000 g of ion-exchanged water had been dissolved, and the number of revolutions was adjusted to an average particle size of 3 to 10 μm using a TK Auto Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) and suspended in water At the very least, a toner dispersion was obtained.

Apart from this, hydrophobic titanium oxide (T-80)
5; Nippon Aerosil Co., Ltd.) is previously dispersed in an aqueous medium using a sand mill (Paint Conditioner; Red Devil Co., Ltd.). The mixture of titanium oxide obtained here was added to the toner dispersion system with respect to 100 parts by weight of the toner solid content.
After adding 0.5 part by weight of the solid content, stirring was further continued to treat the surface of the toner particles with titanium oxide.

Thereafter, filtration / washing was repeated, followed by filtration. The cake-like particles obtained at this time were treated with a hot air drier at 80 ° C. and 85% RH for 5 hours, whereby The particles were aggregated and melted in a state where titanium oxide was present at the interface to obtain a block.

The obtained block was heated at 40 ° C. and 50 RH.
%, And then air-dried for 5 hours.
0 parts by weight, 8 parts by weight of the fine particles a and 0.5 parts by weight of the negative charge control agent LR-147 (manufactured by Nippon Carlit Co., Ltd.) were 3,000 rpm using a Henschel mixer (manufactured by Mitsui Miike Kakoki Co., Ltd.).
For 2 minutes.

The mixture was introduced at an inlet air temperature of 10 ° C.
Kryptron system (manufactured by Kawasaki Heavy Industries; KTM-XL type) with a jacket water cooling system with an exhaust air temperature of 31 ° C and a processing unit of 10 ° C, and a minimum gap of 1 mm between a fixed outer cylinder and a rotatable inner cylinder. ), The particles having a particle diameter of 15 μm or more are classified by a coarse powder classifier (DSX: manufactured by Nippon Pneumatic Co., Ltd.), and the coarse particles are removed again. It was returned to the Kryptron grinder. The fine particles of the obtained particles were classified by using TIPLEX 50ATP (manufactured by Hosokawa Micron) to obtain crushed particles having an average particle size of 6.3 μm.

With respect to 100 parts by weight of the obtained crushed particles, 0.3 parts by weight of hydrophobic silica (R-974: manufactured by Nippon Aerosil Co., Ltd.) and hydrophobic titanium oxide (T-805; manufactured by Nippon Aerosil Co., Ltd.) 6 parts by weight, add Henschel mixer
(Mitsui Miike Kakoki Co., Ltd.), and processed at 3,500 rpm for 3 minutes to obtain toner D.

Example 5 (Production Example of Toner E) As a post-treatment agent added to the crushed particles, hydrophobic silica (R-
974: manufactured by Nippon Aerosil Co., Ltd.) A toner E was obtained in the same manner as in Example 2 except that only 0.3 part by weight was added.

Comparative Example 1 (Production Example of Toner F) Polyester resin (Tuffton NE-382: manufactured by Kao Corporation)
100 g of methylene chloride / toluene (8/2 (wt / w)
t%)) in 400 g of a mixed solvent. The obtained solution and Brilliant Carmine 6B (CI. 15820) 3
g and a calixarene compound (E-89: manufactured by Orient Chemical Industry Co., Ltd.) were placed in a ball mill and mixed for 3 hours to obtain a uniform dispersion.

Next, a 4% solution of methylcellulose (Methocel K35LV: manufactured by Dow Chemical Company) as a dispersion stabilizer was prepared.
TK auto homomixer in an aqueous solution prepared by dissolving 0 g, 1 g of a 1% solution of dioctyl sulfosuccinate soda (Nikkor OTP75: manufactured by Nikko Chemical Co., Ltd.) and 0.5 g of sodium hexametaphosphate (manufactured by Wako Pure Chemical Industries, Ltd.) in 1000 g of ion-exchanged water. The rotation speed was adjusted using (manufactured by Tokushu Kika Kogyo Co., Ltd.), and the uniform dispersion was suspended in water so as to have an average of 3 to 10 μm. After repeated filtration / washing with water, a spray dryer (Dispercoat: manufactured by Nisshin Seifun KK)
And spherical particles having an average particle size of 8.2 μm were obtained.

To the spherical particles, a post-treatment agent was added and post-treatment was performed in the same manner as in Example 1 to obtain a toner F.

Comparative Example 2 (Production Example of Toner G) Polyester resin (Tuffton NE-382: manufactured by Kao Corporation)
100 parts by weight, Brilliant Carmine 6B (CI.15
850) 3 parts by weight and a calixarene compound (E-
89: manufactured by Orient Chemical Co., Ltd.) 2 parts by weight were sufficiently mixed by a ball mill. The mixture was kneaded on three rolls heated to 140 ° C., and the kneaded product was allowed to cool and coarsely pulverized using a feather mill. Further, the coarsely pulverized product is finely pulverized by a jet mill, and the finely pulverized product is classified by wind power to have an average particle size of 6.3 μm.
m amorphous particles were obtained.

A post-treatment agent was added to the irregular shaped particles and post-treatment was performed in the same manner as in Example 1 to obtain a toner G.

Comparative Example 3 (Production Example of Toner H) A block-like material was obtained in the same manner as in Example 1 except that the hot air temperature was 70 ° C. and the exhaust temperature was 60 ° C.

A jacket water cooling system with an inlet air temperature of 10 ° C., an outlet air temperature of 28 ° C., and a processing unit of 10 ° C., and a minimum gap of 5 mm between a fixed outer cylinder and a rotatable inner cylinder were set. Kryptron system (Kawasaki Heavy Industries, Ltd.)
After performing crushing / surface modification treatment at 18,000 rpm by KTM-XL type), air classification was performed and the average particle size was 6.4 μm.
m of crushed particles were obtained.

The obtained crushed particles were subjected to a post-treatment by adding a post-treatment agent in the same manner as in Example 1 to obtain a toner H.

Table 1 summarizes the average particle size, particle size distribution, SF ₁ value and SF ₂ value of the post-treatment agent and toner used to obtain each toner.

[0092]

[Table 1]

Evaluation The obtained toners A to H are mixed with carriers prepared as described below, and a developer is obtained from each.

A ferrite carrier core (F-3000: Spirocoater: manufactured by Okada Seiko Co., Ltd.)
(Powdertech Co., Ltd.) was coated with a thermosetting acrylic-modified silicone resin to obtain a carrier having an average particle size of 50 μm. Note that the carrier particle size is determined by the microtrack model (7
995-10SRA (manufactured by Nikkiso Co., Ltd.).

Next, the toners A to H and the carrier were mixed at a ratio of toner / carrier = 5/95 (weight ratio) to prepare a two-component developer. Using this developer,
For Examples 1-3, 5 and Comparative Example 3, EP-57
Copying was performed using 0Z (manufactured by Minolta), and Example 4 and Comparative Examples 1 and 2 were performed using CF-70 (manufactured by Minolta), and various evaluations were made.

1) Alternative Cleaning Properties The CCD camera 38 from the inside of the photosensitive drum 31 having a charge transport layer formed on a transparent cylindrical substrate using the apparatus shown in the schematic configuration diagram of FIG. The lengths of the post-treatment agent layer and the toner stationary layer were observed, and ranked according to the manner in which they were formed as follows. In addition, there is no practical problem above 以上. A: A post-treatment agent layer or a stationary layer having a uniform width was formed in the longitudinal direction of the cleaning blade. The post-treatment agent layer was formed at 5 μm or more, and the stationary layer was formed at 20 μm or more. ：: A post-treatment agent layer or a stationary layer was continuously formed in the longitudinal direction of the cleaning blade, and there was no broken portion. ×: A post-treatment agent layer or a stationary layer was formed in the longitudinal direction of the cleaning blade, but a broken portion was present.

2) Replenishability Using a chart having a B / W ratio of 30%, the amount of change in toner density when 200 sheets were continuously passed was evaluated, and the results were ranked as follows. ：: The amount of change was 0.5% by weight or less, and there was no practical problem. X: The amount of change was greater than 0.5% by weight, causing problems such as a decrease in image density.

Next, using a chart of 30% B / W, 10,000 copies were made, and the cleaning property, image quality and fog on the image were evaluated at the initial stage and at the end of 10,000-sheet printing. The number of printings using the developer obtained from the toners D, F, and G was 3,000, and the evaluation at this time was the initial and 3,000 printings. However, since the developer using the toner F had poor properties from the beginning, printing was not performed.

3) Cleaning Property The cleaning property was set so that the image density after fixing was set to 1.2 using a square solid chart of B / W 30% in a low-temperature and low-humidity environment of 10 ° C. and 15% RH. Without performing transfer after adjusting the amount of toner development above, visually determine the presence or absence of unwiped toner on the photoreceptor, and visually check the image obtained by performing transfer and fixing under the above conditions. Judged and ranked as follows: Note that △
There is no practical problem. ：: No residual toner was wiped off on the photoreceptor. Δ: The toner was slightly wiped off on the photoreceptor, but did not appear on the image. X: The toner was left unwiped on the photoreceptor, which appeared as noise on the image.

4) Image Properties The image properties were visually evaluated for fine line reproducibility and gradation reproducibility (the number of gray scale reproduction steps by Eastman Kodak Co.) of the line image, and ranked as follows. In addition,
There is no practical problem above Δ. ：: There was no collapse or omission of the line image, and the number of gray scale reproduction steps was 7 or more. Δ: Although the line image was slightly crushed or missing, the number of grayscale reproduction steps could be determined to be 5 to 6 steps. X: The line image was broken or missing, resulting in discontinuity, or the number of gray scale reproduction steps was four or less.

5) Fog on the image Regarding fog on the image, toner fog on the white background image was visually evaluated and ranked as follows. In addition, there is no practical problem with the above. ：: No fog was observed. Δ: Fog was slightly generated. X: Fog was clearly recognized.

Table 2 summarizes the above evaluation results.

[Table 2]

The toner according to the present invention was found to be excellent in blade cleaning properties and image properties, capable of forming a high-quality image without fog, and excellent in replenishability and printing durability.

[0104]

According to the present invention, it is possible to provide a toner which is excellent in blade cleaning properties and image properties, can form a high-quality image without fog, and is excellent in printing durability, replenishability and fluidity.

[Brief description of the drawings]

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

FIGS. 2A, 2B, and 2C are diagrams for explaining the configuration of a rotor and a liner in a mechanical pulverizer.

FIG. 3 is a vertical sectional view at the center of the classifying rotor classifier.

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

FIG. 5 is a schematic configuration diagram of a copying apparatus used to investigate a cleaning alternative characteristic.

[Explanation of symbols]

1: rotor, 2: liner, 3: intake port, 4: exhaust port, 21: classification section, 22: raw material input port, 23: fine powder discharge port, 24: toner discharge port, 25: blade, 31: photoconductor, 32: Charger, 33: Developing device, 34: Cleaning blade, 35: Angle measuring device, 36: Pressure contact spring, 37: Static elimination brush, 38: CCD camera

──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuhiko Takeda Inventor, Osaka International Building Minolta 2-3-1-13, Azuchi-cho, Chuo-ku, Osaka-shi, Osaka (72) Inventor Atsuto Makii Chuo-ku, Osaka-shi, Osaka 2-3-13 Azuchicho Osaka International Building Minolta Co., Ltd. (56) References JP-A-7-49583 (JP, A) JP-A-7-49584 (JP, A) JP-A-7-49585 (JP) , A) JP-A-6-148941 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (2)

(57) [Claims] In a toner for developing an electrostatic latent image comprising at least a binder resin and a colorant, the content of particles having a number average particle diameter of 2 to 9 μm and a particle diameter of 以下 or less of the number average particle diameter is 2 to 2. The content of particles having a particle size of 10% by number and twice or more the number average particle diameter is 1% by number or less, and the average shape factor represented by the following formula is 2/3 or less of the number average particle diameter. The toner for developing an electrostatic latent image, wherein the average shape factor (SF ₁ ) of the particles is larger than the average shape factor (SF ₂ ) of the particles having a number average particle size or more. 2. The method of claim 1] SF ₁ is 120~160, SF ₂ 100
The toner for developing an electrostatic latent image according to claim 1, wherein