JP3161082B2 - toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in an electrophotographic apparatus such as a copying machine and a laser beam printer.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
297691, JP-B-42-23910 and JP-B-43-24748 describe various methods. In general, an electrostatic latent image is formed on a photoreceptor by various optical means using a photoconductive substance, and then the electrostatic latent image is visualized using a toner. After the transfer, the image is fixed by heating or pressure to obtain a copy image.

As a method for visualizing an electrostatic latent image using toner, there are known a magnetic brush method described in US Pat. No. 2,870,063, a cascade developing method described in US Pat. No. 2,618,552, and a method disclosed in US Pat. No. 2,909,258. Various methods, such as the method using the described conductive magnetic toner, are known.

As a developing method, there are mainly a two-component developing method using a mixture of iron powder or glass beads called a carrier and a toner as a developer, and a one-component developing method using a toner alone.

The former two-component developing system is a developing system in which the toner and the carrier are mixed and stirred to charge the toner by mutual frictional charging, so that the chargeability and the transportability are stable.
However, in this method, since the toner is consumed one by one, a function for constantly maintaining the ratio of the toner to the carrier is required.

[0006] As the latter one-component developing system which can be small and light, various magnetic one-component developing systems in which toner is conveyed and held by magnetic force have been devised.

As is well known, in the toner used in these developing methods, the toner coloring base particles obtained after pulverizing and classifying an external additive for the purpose of controlling the charge amount of the toner, imparting fluidity, and imparting cleaning properties are used. It is widely used to add and mix using a mixer or the like. Generally, since the external additive is a fine particle, it has strong cohesiveness.
As described in Japanese Patent No. 68267, a process of loosening to primary particles, that is, a so-called crushing process, is often performed before addition and mixing with toner base particles.

Various methods are used for the crushing process.
In many cases, this is performed by adding an external additive to a mixer or the like and applying a shearing force, or by applying an impact to the external additive using a collision plate type crusher.

[0009]

However, in the above configuration, since the external additive has a cohesive property, the toner
There is a problem that a good adhesion state to the color base particles cannot be achieved, the toner characteristics greatly change depending on the adhesion state of the external additives, and the released external additives film on the photoreceptor.

[0010] This is because the external additive itself diameter has a large chargeability is very small, it and the adhesion unevenness of the external additive is reflected in the charge distribution of the toner, the external additive photosensitive To the body
This is because adhesion is likely to occur. Even if the crushing process is performed, if the addition and mixing are not performed immediately after the crushing, the external additive starts to agglomerate again. I will.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a toner having a high charge, a high fluidity, and a sharp charge amount distribution over a long period of time by improving the adhesion of an external additive to toner base particles by a simple method. The purpose is to provide.

[0012]

In order to solve the above-mentioned problems, a toner according to the present invention comprises mixing toner-colored base particles having at least a colorant and an external additive in a mixing tank having stirring blades. The colored base particles are previously injected into a mixing tank having a stirring blade, which is a toner prepared by processing.
After the addition, the toner is characterized in that an external additive is injected while being dispersed and sprayed using compressed air, and is subjected to a mixing external addition process with the toner-colored base particles.

Further, the present invention provides a coaxial double
The external additive is dispersed and sprayed from the pipe nozzle, and the toner is
It is characterized by carrying out mixed external addition treatment with colored base particles
Toner.

Further, the present invention provides that the colorant is a magnetic substance.
And a toner characterized by the following. Furthermore, the present invention provides a magnetic material
Is 20 to 60% by weight based on the weight of the toner.
Toner.

Further, according to the present invention, the amount of the external additive added to the toner
The toner is 0.01 to 5% by weight based on the weight.

Externally added from the coaxial double tube nozzle by compressed air
Dispersant sprayed and mixed with the toner coloring base particles in the mixing tank.
When the external additive treatment is performed, the crushing effect of the external additive is high.
No. Further, the external additive is separated into a mixing tank having stirring blades.
Discharge is performed while spraying, so disintegration is almost the same as the external addition process.
Without disaggregation of external additives after crushing.
The toner-colored base particles are mixed with the toner-colored base particles.
External additives uniformly adhere to the surface.

As a result, the charge amount distribution of the toner becomes uniform,
No external additive adheres to the photoreceptor. Conventionally, German
This eliminates the need for the external additive to be broken up
And the production process can be simplified.

Hereinafter, the toner of the present invention will be described in detail.
You. The toner in the present invention is at least a binder resin.
Toner base particles composed of a toner and a colorant, and an external additive.
Is done. All known binder resins
Can be used, for example, styrene resin, acrylic
Resin, polyester resin, epoxy resin, vinyl resin
Fats, terpene resins, phenolic resins or their
A copolymer resin or the like is used.

As the pigment or dye used for the coloring agent,
Various magnetic materials, carbon black, iron black, graphite,
Nigrosine, metal complex of azo dye, phthalocyanine bull
ー, Dupont oil red, aniline blue, benzine
Use yellow, rose bengal or a mixture of these.
Can be

As the magnetic material, ferrite, magnetite
Iron, manganese, cobalt, nickel such as hematite
Alloys and compounds such as copper, zinc, magnesium, etc.
Substances known as magnetic substances can be used. These magnetic
The particles have a mean particle size of about 0.05 to 5 μm, preferably 0.1 to 1 μm.
20 to 60% by weight as a powder in the toner
No.

External additives include silica, alumina, titani
A, zirconia, magnesia, yttria, ferrai
Fine powder of metal oxides such as
Oxide fine powder, carbide such as tungsten carbide,
Other nitrides, barium titanate, calcium titanate
Titanates such as strontium titanate, zircon
Barium acid, calcium zirconate, zirconate stro
Zirconate such as nthium or a mixture thereof
Can be. External additives may be subjected to surface treatment such as hydrophobic treatment if necessary.
May be applied. Also, polymethyl methacrylate,
Organic polymer fine powder such as polyvinylidene fluoride is used
You.

These fine powders are used in
The content may be 0.01 to 5% by weight.

The toner of the present invention may further contain
The flow of release agents and fine powders of organic materials as additives and external additives
Includes mobility, charging, and cleaning aids
be able to.

[0024]

According to the present invention, a toner having a high charge, a high fluidity, and a sharp charge amount distribution can be provided for a long period of time by improving the adherability of the external additive to the toner-colored base particles by the above constitution. Thus, high image quality during printing and stable image density can be achieved.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to this.

The toner of the present invention uses a stirring blade as a production method.
Mix the toner coloring base particles and the external additive in the mixing tank
It is created by external addition processing. In this embodiment, the toner coloring mother
Body particles are at least a mixing step, a kneading step, a pulverizing step,
Manufactured through a classification process and an external addition process.
Other methods may be used. Known methods are used as a mixing method, a kneading method, a pulverizing method, and a classification method. That is, the resin and the internal additive such as a colorant are mixed by a high-speed fluid mixer such as a Henschel mixer or a super mixer, and then kneaded. As a kneading method at this time, a known heating kneader can be used. As the heating kneader, a device such as a three-roll type, a single screw type, a twin screw type, or a Banbury mixer type that heats and kneads a kneaded material with a shearing force can be used. In this example , a PCM-30 type twin-screw kneader manufactured by Ikegai Iron Works was used. The present invention is not limited to this. The kneaded material is coarsely pulverized by a cutter mill or the like, and then finely pulverized by a collision plate type pulverizer or a rotor rotary type pulverizer. obtain. That
After that, in a mixing tank equipped with stirring blades, the toner is colored.
The external additive is dispersed and sprayed into the base particles while being dispersed and mixed.
An external addition process is performed to obtain a toner. Equipped with stirring blades
Henschl mixer, Super Miki
A high-speed fluid type mixer such as a mixer can be used.
It is not limited to this.

The external additive is a coaxial double tube nozzle with compressed air.
Sprayed. The compressed air at this time is air pressure
0.1 to 3 kg / cm ² G is preferable. In this embodiment,
The operation was performed at 0.8 kg / cm ² G. 0.1kg / c
If it is less than m ² G, no crushing effect can be obtained. 3 kg / cm ² G
Above, there is no change in the crushing effect. The air volume is 0.8kg
/ Cm ² G time is preferably 0.01 to 0.1 m ³ / min
In this embodiment, the measurement was performed at 0.04 m ³ / min.
Injects compressed air into the mixing tank
A filter may be attached.

The charge amount of the toner was measured by mixing the carrier and the toner and charged by a blow-off charge amount measuring device (TB-200, manufactured by Toshiba Chemical Corporation). The carrier used was TEFV200 / 300 (Powder Tech), and the toner concentration was adjusted to 3%.
After mixing for 10 minutes, the measurement was performed at a blow pressure of 1 kg / cm ² .

FIG. 1 shows a coaxial double tube nozzle used in the present invention. The coaxial double tube nozzle has an external cylinder nozzle 1 that introduces a high-speed airflow obtained by compressed air from a tangential direction to the central axis, and an external additive fine together with the external air by the suction effect of the high-speed swirling airflow of the external cylinder nozzle from the same tangential direction. It comprises an inner cylinder nozzle 2 for introducing powder. The external additive fine powder is disintegrated and sprayed by a high-speed swirling flow generated in the throat portion 3 of the coaxial double tube nozzle.

FIG. 2 shows an external processing unit used in the present invention. 4 is a coaxial double tube nozzle, 5 is a stirring blade
Mixing vessel equipped with a 6 toner colored base particles, the 7 external additive feeder, 8 compressed air introduction section, 9 is a stirring blade. Example 1 The material composition of the toner a1 used in Example 1 is shown in (Table 1).

[0031]

[Table 1]

Among the substances shown in Table 1, resins and colorants
Magnetic material as, and mixed after melt-kneading the charge control agent, cooled grinding, classifying to obtain toner colored base particles having an average particle size of 10 [mu] m. 2 kg of the toner-colored base particles were put into a Henschel mixer FM-20B manufactured by Mitsui Miike Kakoki Co., Ltd., and a predetermined amount of hydrophobic silica was fed through a coaxial double tube nozzle for 30 seconds.
The Henschel mixer was operated at 2000 rpm for 5 minutes while jetting was performed to obtain a toner powder.

The toner was converted to a toner by using a modified laser beam printer FP-L330 manufactured by Matsushita Electric Industrial Co., Ltd.
A print test was performed on 000 sheets, and the image density was measured and evaluated using a reflection densitometer (Macbeth). Table 2 shows the change in the image density of each toner, and Table 3 shows the change in the charge amount at the initial stage and after printing 10,000 sheets. There is little change in the amount of charge due to printing, and a high-resolution high-quality image that reproduces 16 lines / mm image lines with uniform solids and a density of 1.5 without horizontal line disturbance or toner scattering is obtained. Even after printing 10,000 sheets, a high-density copy was obtained, which was comparable to the initial image.

[0034]

[Table 2]

[0035]

[Table 3]

Example 2 The material composition of the toner a2 used in Example 2 is shown in (Table 4).

[0037]

[Table 4]

Among the substances shown in Table 4, resins and colorants
Magnetic material as, and mixed after melt-kneading the charge control agent, cooled grinding, classifying to obtain toner colored base particles having an average particle size of 10 [mu] m. The toner colored base particles and 2kg put into Ltd. Mitsui Miike Machinery Henschel mixer FM-20B, injection while Henschel Mi predetermined amount of the hydrophobic silica with a coaxial double-tube nozzle, a tungsten carbide 30 seconds <br The xer was operated at 2000 rpm for 5 minutes to obtain a toner powder.

This toner was subjected to a printing test of 30,000 sheets using the same apparatus as in Example 1 and evaluated. As a result, there was no disturbance of horizontal lines or scattering of toner, and the solid was uniform and had a density of 1.5 lines / mm. A high-resolution and high-quality image that reproduced the image was obtained. Further, even after printing of 30,000 sheets, a high-density copy having no inferiority to the initial image was obtained without filming or scratches on the photoreceptor. Example 3 The material composition of the toner a3 used in Example 3 is shown in (Table 5).

[0040]

[Table 5]

Among the substances shown in Table 5, resins and colorants
Magnetic material as, and mixed after melt-kneading the charge control agent, cooled grinding, classifying to obtain toner colored base particles having an average particle size of 10 [mu] m. The toner colored base particles and 2kg put into Ltd. Mitsui Miike Machinery Henschel mixer FM-20B, a predetermined amount of the hydrophobic silica with a coaxial double-tube nozzle, polymethylmethacrylate powder hen while spraying for 30 seconds
The shell mixer was operated for 5 minutes at 2000r.pm, toner
-A powder was obtained.

This toner was subjected to a printing test on 10,000 sheets using the same apparatus as in Example 1 and evaluated. As a result, no disturbance of horizontal lines, scattering of toner, fogging of the background, etc. were observed, and the toner was uniform and had a density of 1.5. A high-resolution and high-quality image that reproduced a line / mm image was obtained. Even after printing 10,000 sheets, a high-density copy was obtained, which was comparable to the initial image. Comparative Example 1 Among the substances shown in (Table 1), magnetism as resin and colorant
The toner and the charge control agent are mixed and melt-kneaded in the same manner as in Example 1, cooled, pulverized and classified to form a toner having an average particle diameter of 10 μm.
Colored base particles were obtained. 2 kg of the toner-colored base particles and hydrophobic silica were charged into a Hensle mixer FM-20B manufactured by Mitsui Miike Kakoki Co., Ltd., and operated at 2000 rpm for 5 minutes to obtain a toner powder b1.

When this toner was evaluated in the same manner as in Example 1, the change in the charge amount due to printing was large, and the image density was reduced from about 500 sheets, and a practical image could not be obtained. The released silica aggregates adhered as white spots on the image. Comparative Example 2 Among the substances shown in (Table 4), magnetism as resin and colorant
The toner and the charge control agent are mixed and melt-kneaded in the same manner as in Example 2, cooled, pulverized and classified to obtain a toner having an average particle diameter of 10 μm.
Colored base particles were obtained. 2 kg of the toner-colored base particles , hydrophobic silica, and tungsten carbide were charged into a Hensle mixer FM-20B manufactured by Mitsui Miike Kakoki Co., Ltd., and operated at 2000 rpm for 5 minutes to obtain toner powder b2.

When this toner was evaluated by the same method as in Example 2, the change in the charge amount due to printing was large, and the image density was reduced from about 500 sheets, and a practical image could not be obtained. In addition, the released silica aggregates adhered as white spots on the image, and a number of scratches probably caused by the tungsten carbide aggregates occurred on the photoreceptor, resulting in poor print quality. Comparative Example 3 Among the substances shown in (Table 5), magnetism as resin and colorant
The toner and the charge control agent were mixed and melt-kneaded in the same manner as in Example 3, cooled, pulverized and classified to obtain a toner having an average particle diameter of 10 μm.
Colored base particles were obtained. 2 kg of the toner-colored base particles and hydrophobic silica and polymethyl methacrylate fine powder were mixed with Hensle mixer FM-2 manufactured by Mitsui Miike Kakoki Co., Ltd.
0B and operated at 2000 rpm for 5 minutes to obtain toner powder b3.

When this toner was evaluated in the same manner as in Example 3, the charge amount was extremely low, and a practical image could not be obtained from the beginning. This is presumably because silica aggregated with the polymethyl methacrylate fine powder as the core, and the adhesion of the external additive to the toner-colored base particles was significantly deteriorated.

[0046]

As described above, the present invention has a stirring blade.
External additive to the mixing tank using a coaxial double tube nozzle
By dispersing and spraying to create mixed externally added toner
Ri, by improving the external additive adhesion to toner colored base particles, highly charged for a long time, high fluidity, it is possible to provide a toner having a sharp charge quantity distribution, high image quality at the time of printing, Image density stabilization can be achieved.

[Brief description of the drawings]

FIG. 1 shows a coaxial double tube nozzle according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an external processing unit in an embodiment of the present invention.

[Description of Signs] 1 Outer cylinder nozzle 2 Inner cylinder nozzle 3 Throat section 4 Coaxial double pipe nozzle 5 Mixing tank with stirring blade 6 Toner coloring base particles 7 External additive feeder 8 Compressed air introduction unit 9 Stirring blade

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-34971 (JP, A) JP-A-62-283029 (JP, A) JP-A-2-157027 (JP, A) JP-A-2- 167559 (JP, A) JP-A-3-56131 (JP, A) JP-A-56-6248 (JP, A) JP-A-57-129444 (JP, A) JP-A-57-158653 (JP, A) JP-A-62-260159 (JP, A) JP-A-3-259156 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08-9/087

Claims (5)

(57) [Claims] 1. A toner prepared by mixing and externally adding a toner coloring base particle having at least a coloring agent and an external additive in a mixing tank having a stirring blade, comprising the stirring blade. In the mixing tank, the colored base particles
After pre-charged, the external additive was charged while dispersing spraying with compressed air, the toner which is characterized in applying a mixture system adding processing and the toner colored base particles. 2. The toner according to claim 1, wherein the external additive is dispersed and sprayed from the coaxial double tube nozzle by compressed air, and the external additive treatment is performed with the toner-colored base particles in the mixing tank. 3. The toner according to claim 1, wherein the colorant is a magnetic material. 4. The toner according to claim 1, wherein the amount of the magnetic material is 20 to the weight of the toner.
4. The toner according to claim 3, wherein the amount is from about 60% by weight. 5. The amount of the external additive to be added is 0.1 to the weight of the toner.
3. The toner according to claim 1, wherein the amount is from 0.01 to 5% by weight.