JP2658003B2 - Photoconductive toner and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photoconductive toner. More specifically, the present invention uses a fine photoconductive material, and significantly improves various characteristics of the toner including photosensitivity. The present invention relates to a photoconductive toner.

(Prior Art and Problems Thereof) Conventionally, an image forming method using a photoconductive toner has been proposed as a method for forming an image without using a photosensitive drum. It is getting more and more attention.

The above-mentioned photoconductive toner is obtained by dispersing a photoconductive material in a fixing resin having fixability and electric detection and granulating the particles into micron-order particles, and the toner itself has photoconductivity. Things. Previously, we used JP-A-1-1372.
In Japanese Patent Publication No. 70 (Japanese Patent Application No. 62-295343), an image forming method using a photoconductive toner was proposed.

In an image forming method using a photoconductive toner, as described in the above specification, in connection with the exposure of the charged toner layer, it is completely different from a normal visible toner. It creates different problems. That is, the photosensitive layer is composed of a layer of independent toner particles, and an image is formed by a change in electric charge and a change in Coulomb force due to the photoconductivity of the toner particles. In order to obtain a proper image, various characteristics required for the toner, such as photosensitivity, particle size characteristics, charging stability, and fluidity, become more severe, and any one of the above-mentioned various characteristics of the toner is required to be at a certain level. At the present time, a good image cannot be obtained when the temperature is lowered.

Conventionally, particles having a specific surface area of about ^{2 to} 7 m ² / g are generally used as zinc oxide, titanium oxide and the like, which are inorganic photoconductive materials used for photoconductive toner. In order to demonstrate the photoconductivity required for image formation, the photoconductive material must be contained in an amount of 50% by weight or more based on the fixing resin, and the surface of the toner in which the photoconductive material is dispersed has an inorganic photoconductive property. To form a thin toner layer with a uniform and uniform layer thickness and surface potential, because the material is exposed and reduces the fluidity of the toner and gives a large difference in the charge of each toner. Was difficult. In addition, the scattering property of the irradiation light in the toner particles is not satisfactory, and the light sensitivity (how efficiently the charge of the toner layer is lost by light irradiation from the surface potential of the charged toner layer) is lowered. Thus, it was still difficult to form a toner image having excellent contrast.

The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to provide a photoconductive toner capable of forming a toner image having a high contrast without causing blurring of characters and image fogging. It is in.

Still another object of the present invention is to provide a photoconductive toner having excellent fluidity, toner thin layer forming property and triboelectric charging property.

It is a further object of the present invention to provide photoconductivity capable of forming a vivid image.

It is a further object of the present invention to provide a photoconductive toner having significantly improved photosensitivity and a method for producing the same.

(Means for Solving the Problems) According to the present invention, there is provided a photoconductive toner in which at least 50 parts by weight of an inorganic photoconductive material is dispersed in 100 parts by weight of a fixing resin. The photoconductive material has a specific surface area of 8 to 20 m ² / g,
Also provided is a photoconductive toner having a surface on which a fatty acid and a sensitizing dye are adsorbed.

Further, according to the present invention, a step of immersing the inorganic photoconductive material in an organic solvent in which the fatty acid is soluble, and adding the fatty acid and the sensitizer to the solution and adsorbing the sensitizer on the surface of the inorganic photoconductive material. A method for producing a photoconductive toner is provided.

(Effect) The present invention relates to a fixing resin, wherein
A photoconductive toner in which 0 parts by weight or more of an inorganic photoconductive material is dispersed, wherein the inorganic photoconductive material has a specific surface area of 8 to 20 m ^2.
/ g, and a fatty acid and a sensitizing dye are adsorbed on the surface to produce a photoconductive toner, which improves the charging characteristics, fluidity, and photosensitivity of the photoconductive toner. This is based on the finding that a clear toner image can be formed without causing blurred characters and image fogging.

In other words, the photoconductive toner of the present invention using an inorganic photoconductive material having a specific surface area of 8 to 20 m ² / g and having a fatty acid and a sensitizing dye adsorbed on the surface thereof has an inorganic property with respect to the fixing resin. Even if the photoconductive material is contained at 50% or more, the surface of the inorganic photoconductive material is less exposed to the surface of the toner particles because of good dispersibility. In addition, since the scattering property of the irradiation light in the toner is increased, the amount of irradiation on the photoconductive material is substantially increased, and a clear image with a high contrast can be formed.

Also, it is possible to make the inorganic photoconductive material have sensitivity in the visible region by adsorbing the sensitizer to the inorganic photoconductive material,
Further, by adsorbing the fatty acid, the dispersibility of the inorganic photoconductive material in the fixing resin can be improved.

The photoconductive toner of the present invention can provide a good result in any process as long as the photoconductive toner is used in a process of forming a charged toner thin layer, exposing the thin toner layer to an image, and forming an image. .

Hereinafter, the present invention will be described in more detail with reference to specific examples of an image forming process using a photoconductive toner.

FIG. 2 employs a two-component magnetic brush development comprising a photoconductive toner and a magnetic carrier, which we previously filed, and uses a photoconductive toner that forms a positive image by a voltage application simultaneous exposure simultaneous transfer method. FIG. 3 is a diagram illustrating an image forming method. Referring to FIG. 2, a magnetic brush 15 made of a mixture of a magnetic carrier 17 and a photoconductive toner 13 on a developing sleeve (conductive sleeve) 16 will be described. Make this magnetic brush
15 is brought into contact with the transparent electrode surface 2 of the transparent drum 3.

The photoconductive toner 13 is charged to a charge of a fixed polarity (for example, minus) by mixing with the magnetic carrier 17, and is attracted by the Coulomb force to the magnetic carrier 17 charged to the charge of the opposite polarity. The transparent electrode surface 2 has a polarity (for example, plus) opposite to the polarity of the photoconductive toner 13.
The bias potential is applied by the power supply 19, or the power supply 19 is grounded. Thus, a thin layer 26 of photoconductive toner 13 is formed on transparent electrode surface 2. The slit exposure is performed on the toner layer 26 via the transparent drum 3 and the transparent electrode surface 2. Photoconductive toner in dark area D
13 remains on the electrode surface 2 by the Coulomb force, but in the light portion L, the charge disappears or the opposite polarity charge (for example, plus) is injected due to the photoconductivity of the toner 13, and the toner 13 is The toner image 25 is formed on the dark portion D by moving to the side 15.

When a thin toner layer is formed on a toner-coated surface such as a transparent electrode surface by a magnetic brush composed of a carrier and a toner as in the above-described image forming method, the toner layer has a uniform and uniform toner layer thickness and surface potential. In order to form a thin toner layer, it is required that the toner is sufficiently stirred in a developing device to form a magnetic brush in which the toner is uniformly dispersed. In the simultaneous exposure / simultaneous transfer method, the toner whose charge has been attenuated after exposure must be quickly scraped off by a magnetic brush. The surface properties and the particle size of the toner also have a great effect. The toner in which the fine inorganic photoconductive material having a specific surface area of the present invention in the range of 8 to 20 m ² / g is dispersed in the fixing resin,
As described above, not only the surface exposure of the inorganic photoconductive material is prevented, but also the content of the inorganic photoconductive material in each toner is uniform since the photoconductive material can be finely and uniformly dispersed in the fixing resin. In addition, since the particle size is easily adjusted during the production of the toner, the photosensitivity and the fluidity are excellent in any preferable particle size range, and the characteristics of each particle are small. Form a layer,
Scraping the exposed toner with a magnetic brush (transfer)
In a method in which the fluidity of the toner particles greatly affects the image as described above, the photoconductive toner of the present invention can provide more preferable results.

(Preferred Embodiment of the Invention) Inorganic photoconductive material As the inorganic photoconductive material used in the present invention, fine particles having a specific surface area of 8 to 20 m ² / g, such as zinc oxide, titanium oxide, cadmium sulfide, selenium, and zinc sulfide, are used. Any of them can be used.

If the specific surface area of the inorganic photoconductive material is smaller than the above range, it is not preferable in terms of photosensitivity and exposure of the inorganic material on the surface of the toner particles, and if the specific surface area is larger than the above range, During the production of the toner, the particles aggregate, making it difficult to uniformly and uniformly disperse the toner.

The amount used is generally 50 to 500 parts by weight, especially 100 to 350 parts by weight, based on 100 parts by weight of the fixing resin exemplified below.
Parts by weight can be used.

Fixing resin As the fixing resin in which the photoconductive material is dispersed, an electric insulating resin known per se, for example, a suthrene-based polymer, an acrylic-based polymer, a styrene-acryl-based polymer,
Polyvinyl chloride, polyester, polyamide, polyurethane, epoxy resin, diallyl phthalate resin, silicone resin, phenol resin, rosin-modified phenol resin, rosin ester, polyvinyl butyral, polysulfone, etc. can be used. Conductive resins are also used in the present invention, alone or in combination with an electrically insulating resin.

In the present invention, a dye sensitizer or a chemical sensitizer known per se can be blended.

Specific examples of the sensitizer include rose bengal, eosin, fluorescein, brilliant carmine, thioflavin, acludine orange, erythrosin, bromophenol blue, and the like.
In general, it is preferable to use 0.01 to 0.5 parts by weight, particularly 0.05 to 0.2 parts by weight, per 0 parts by weight. Also,
A charge transport material may be used as a fixing medium, and the above-described photoconductive material may be dispersed as a charge generating material in the charge transport material, and the dispersion may be used as a photoconductive toner.

Examples of the charge transport medium include the above-described electric insulating resin and a charge transport material, for example, polyvinyl carbazole, phenanthrene, N-ethyl carbazole, 2,5-diphenyl-1,3,4-oxathiazole, and 4,4 ′. Holes such as -bis (diethylamino) -2,2'-dimethyltriphenylmethane, 2,5-bis- (4-diethylaminophenyl) -1,3,4-triazole, p-diethylaminobenzaldehyde- (diphenylhydrazone) Transport substances and 2-nitro-
Electron transport materials such as 9-fluorene, 2-nitrobenzothiophene and anthraquinone are generally referred to as resin 10
It is preferably used in an amount of 10 to 200 parts by weight, especially 30 to 120 parts by weight, per 0 parts by weight.

Toner property imparting agent In addition to the above-described essential components, a toner property imparting agent known per se can be added to the photoconductive toner of the present invention in accordance with a known formulation.

Examples of such a toner property imparting agent include an anti-offset agent, a colorant, and a charge control agent.

As an anti-offset agent, polyethylene wax,
Various waxes such as polypropylene wax and ethylene-propylene wax, and low molecular weight olefins such as olefin monomers having 4 or more carbon atoms are used. These anti-offset agents are generally 0.1 parts by weight per 100 parts by weight of the fixing resin.
It may be added in an amount of from 10 to 10 parts by weight.

As the coloring agent, one or more known coloring agents such as carbon black, cadmium yellow, molybdenum orange, pyrazolone red, fast violet B, and phthalocyanine blue are used.

As the charge control agent, for example, nigrosine base (CI
50415), oil-soluble dyes such as oil black (CI26150) and spiron black, metal salts of naphthenic acid, metal salts of fatty acids, and resin acid soaps.

Sensitizing treatment of inorganic photoconductive material and method for producing toner The inorganic photoconductive material used in the photoconductive toner of the present invention is subjected to immersion treatment in an organic solvent in which a sensitizer is dispersed or compatible, and Sensitizes by adsorbing a sensitizer on the surface of the conductive material.

Examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, tert-butanol, hexanol, and octanol; ethers such as dioxane, tetrahydrofuran, dimethyl ether, diethyl ether, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether. , Acetone, methyl ethyl ketone, ketones such as cyclohexanone, esters such as ethyl acetate and methyl acetate, and various organic solvents such as acetonitrile, formaldehyde, dimethylformaldehyde and pyridine.
These are used alone or in combination of two or more.

Also, to further improve the adsorption of the sensitizer to the inorganic photoconductive material and the dispersibility of the sensitized inorganic photoconductive material in the fixing resin, a fatty acid is dissolved in a solvent together with the sensitizer, An immersion treatment of the inorganic photoconductive material is performed. In this case, it is preferable to use cyclic ethers such as tetrahydrofuran and ketones such as acetone from the viewpoint of removing the solvent after treating the solubility of fatty acids among the organic solvents. According to such an embodiment, since the fatty acid compounded in the toner may reduce the triboelectric charging property and the fluidity of the toner, it is necessary to select a specific fatty acid before use.

Examples of the fatty acids include caprylic acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, stearic acid, behenic acid, lignoceric acid, serotinic acid, montanic acid, oleic acid, elaidic acid, linoleic acid, linoleic acid, erucic acid, Examples thereof include ricinoleic acid, dihydroxystearyl acid, cyclic fatty acids, dibasic acids, and dimer acids which are dimers of the above-mentioned unsaturated single fatty acids. Among the above fatty acids, saturated fatty acids, particularly stearic acid, are preferred. These fatty acids vary depending on the photoconductive material used, but generally 0.1 to 10 per 100 parts by weight of the photoconductive material.
Part by weight is used, and in particular, 1 to 2 parts by weight is preferably used.

The immersion reaction time varies depending on the photoconductive material and the sensitizer used, but is generally preferably about 0.5 to 50 hours. Further, at this time, the treatment can be efficiently performed by using a dispersing device such as ultrasonic irradiation or a homogenizer.

The toner of the present invention dissolves the fixing resin in a solvent in which the fixing resin dissolves, such as toluene, and further disperses the photoconductive material subjected to the sensitization treatment and other additives to be added as necessary. After dissolving, granulating by spray drying or fixing resin, sensitized photoconductive material and other additives are melt-kneaded, the obtained melt-kneaded product is cooled and pulverized, Classify into photoconductive toner particles. The toner particles generally have an average particle size of 3 to 20 μm, particularly,
Preferably, the volume-based median diameter is in the range of 5 to 10 μm, and the standard deviation of the volume-based particle size distribution is 3.33 μm.
m. Of the above manufacturing methods, the spray drying method is preferably used because the shape of the generated toner is spherical.

In the present invention, a toner having a particle size characteristic in the above-mentioned range has a good toner thin layer forming property and a good charge attenuating property upon light irradiation, and has a toner charge amount per unit weight and light per particle. The balance of the decay speed is optimized, and the transfer of the toner to the brush after the charge decay in the case of using the magnetic brush becomes smooth, so that a more preferable result can be obtained.

Further, the toner of the present invention has a shape represented by the following formula: In the formula, r _L represents the major axis of the toner particles, r _s represents the minor axis of the toner particles, and a spherical shape having a circularity (D) defined by the following expression of 0.9 to 1.0 is more preferable. give.

Further, when the shape of the particles is in the above-mentioned circularity range, not only the toner thin layer forming property but also the toner attenuated after exposure to light is easily separated from the toner thin layer.

In the photoconductive toner of the present invention, for the purpose of improving various physical properties of the toner, silica as a fluidity modifier, alumina, titanium oxide, silicane oil or the like as a dispersibility improver is 0.4 to 100 parts by weight of the toner. It can be used in a quantitative ratio of 2.0.

When the toner of the present invention is mixed with the above-mentioned magnetic carrier to form a developer, any magnetic carrier conventionally used in the field of electrophotography is used as the magnetic carrier to be used. In addition, an irregular or spherical carrier can be used.

The particle size (number average particle size) of the carrier is generally 40
Of 110 to 110 μm, especially 40 to 60 μm, and in relation to this particle size, the specific surface area is 50 to 500 cm ² / g, in particular 30
It is in the range of 0 to 400 cm ² / g.

A preferable example of the magnetic carrier is a square shaped irregular iron powder (hereinafter simply referred to as an irregular spherical shape) having a particle diameter of 10%.
90% by weight or more of 5μm or less, 37 to 7
A particle size distribution in which 4 μm is 50% or more of the whole;
Those having a loose apparent specific gravity of 3.20 g / cc to 3.20 g / cc are preferably used.

Another preferred example of the magnetic carrier is a so-called ferrite carrier, and the sintered ferrite particles, particularly the spherical sintered ferrite particles, generally have a particle size of 20 to 100 μm.
It is good to be in the range.

When the particle size of the sintered ferrite particles is smaller than 20 μm, there is a tendency that it is difficult to make the magnetic brush ears good, and when the particle size is larger than 100 μm, There is a tendency that the above-mentioned brush mark, that is, a scratch, is formed in the toner image to be formed.

Further, the surface of the magnetic carrier particles may be thinly coated with an acrylic resin, a silicone resin, or the like.

Although the particle size of the toner particles is preferably in the above-mentioned particle size distribution, when a two-component developer is used, in terms of the specific surface area, it is generally 5,000 to 20,000 cm ² / g, and particularly one having a particle size of 7500 to 10,000 cm ² / g. Preferably, the mixing ratio of the toner with the magnetic carrier, that is, the toner concentration, satisfies the following expression.

In the formula, _Sc is the specific surface area (cm / g) of the magnetic carrier. K is a number of 1.0 to 2.0. That is, the toner concentration of a normal two-component developer (K
Is formed at a concentration significantly lower than 0.8 to 1.14). When the toner layer is formed at this toner density, the toner adhesion amount optimally acts on the optical sensitivity of the optimum toner, and a toner image free of fog and satisfying the image density can be obtained.

 Hereinafter, the present invention will be described with reference to examples.

(Experimental Example 1) As zinc oxide particles, the specific surface area (m ² / g) is 2.1, 2.5,
Using toners of 4.5, 5.5, 8.3, 13.0, 18.5, and 23.0, toners were obtained according to the following formulation.

Sensitization treatment 100 parts by weight of zinc oxide is immersed in 200 parts by weight of methanol,
0.2 parts by weight of erythrosin B (sensitizing dye) and 2 parts by weight of stearic acid are added and sensitized. Next, this solution was filtered and dried to obtain sensitized zinc oxide particles having different specific surface areas.

Toner production 30 parts by weight of sensitized zinc oxide particles and 10 parts by weight of fixing resin (styrene-acrylic resin) are added to 300 parts by weight of toluene, dissolved and dispersed, and the obtained resin solution is dispersed, mixed and sprayed. The toner was adjusted to an average particle diameter of 10 μm by a dry method.

The toner,...,...

5 parts by weight of the obtained photoconductive toner is mixed with 95 parts by weight of a ferrite carrier and triboelectrically charged, and the photoconductive toner is uniformly and uniformly applied on an aluminum substrate by using a magnetic brush device for an electrophotographic copying machine. In the same manner.

The formed photoconductive toner layer was irradiated with monochromatic light (550 nm) taken out of a monochromator for 0.5 seconds, and the initial surface potential and the surface potential 1.5 seconds after irradiation were measured, and a computer connected to a digital oscilloscope was used. The decay rate of the surface potential (maximum decay rate of the surface potential) was measured by the following method.

 The results are shown in Table 1 and FIG.

The image in the table is a copy image obtained by exposing the photoconductive toner layer to an image, then overlaying the transfer paper, and performing a positive corona discharge from the back and transferring the image. It was evaluated.

As is clear from Table 1 and FIG. 1, the photoconductive toner using the zinc oxide particles having a specific surface area in the range of 8 to 20 according to the present invention has improved photosensitivity and has a lower surface potential of the toner layer. It can be seen that the attenuation is performed efficiently, and as a result, fog is reduced and a high-density image is obtained. Further, it can be seen that the treatment with the fatty acid is effective for those having a specific surface area of 8 to 20.

(Experimental Example 2) Using zinc oxide having a specific surface area of 13 m ² / g in Experimental Example 1, changing the processing solvent from methanol to tetrahydrofuran, and performing sensitization treatment in combination with stearic acid, the sensitization treatment was performed. A toner was prepared using zinc oxide.

The maximum surface potential decay rate of this toner was 66%, and the copied image obtained was good.

This indicates that when sensitizing treatment is performed using a fatty acid such as stearic acid, ethers such as tetrahydrofuran are preferable.

(Experimental Example 3) The zinc oxide having a specific surface area of 4.5, 8.3, and 13.0 m ² / g was used, and the particle size characteristics shown in Table 2 below were obtained by a spray drying method under the same formulation as in Experimental Example 1. A toner having the same was prepared. Then, a ferrite carrier having a particle size of 70 μm (number average particle size) and a specific surface area of 350 cm ² / g and a toner concentration were adjusted to 5%, and the transfer sensitivity was measured by the apparatus shown in FIG. , And by the device shown in FIG.
100 sheets of continuous images were formed.

Hereinafter, a method of measuring the transfer sensitivity will be described with reference to FIG. 3. A stirring roller 41 for stirring the magnetic carrier and the toner will be described.
And a developing device 44 including a developing sleeve 42 connected to a bias power source, and a spike 43 for adjusting the spike length of the magnetic brush.
The developer is charged with a constant toner concentration to form a magnetic brush. Then, while rubbing the surface of the Nesa glass 51 connected to the bias power supply with this magnetic brush, a halogen lamp 61 as a light source, a slit 62 for regulating the light amount and irradiation width, and an interference filter 63 on the surface are provided substantially simultaneously. The contact surface of the magnetic brush is exposed by an exposure device 65 including a lens 64.

Then, the irradiation portion and the unirradiated portion of the NESA glass, the weight of Nesa glass having the toner adhered was measured, the irradiation portion and M _L, the non-irradiated portion as M _D, Was measured.

To explain the image forming apparatus shown in FIG. 4, a transparent drum 3 provided with a transparent electrode 2 on the outer surface is rotatably provided inside the machine casing 1. A transparent plate 5 for supporting the original 4 is provided on the upper part of the machine frame 1. An exposure mirror 6 is fixed substantially at the center of the transparent drum 3, and the exposure mirror 6 and the transparent plate 5 are, for example, a first operating mirror 7, a second operating mirror 8, an in-mirror lens 9, And optically connected via a fixed mirror 10. An exposure lamp 11 is provided to illuminate the original 4 on the transparent plate 5.

Along the periphery of the transparent drum 3 and in the optical path from the exposure mirror 6, a developing device indicated by 12 is provided. The developing device 12 includes a stirring roller 14 for mixing the supplied photoconductive toner 13 and the magnetic carrier 17 (see FIG. 3), and a developing sleeve 16 for forming a magnetic brush 15 of the mixture on the surface. Consists of The surface of the developing sleeve 16 is conductive, and a magnet 18 for forming a magnetic brush is rotatably provided inside the developing sleeve 16. In this embodiment, the transparent electrode surface 2 is provided to apply a bias voltage between the transparent electrode surface 2 and the developing sleeve 16, while the developing sleeve 16 is connected to a bias power supply 19.

Along with the developing device 12, a toner image transfer mechanism 20 is provided along the rotation direction of the transparent drum 3. That is, a copy paper feed mechanism 22 that supplies the copy paper 21 so as to come into contact with the surface of the transparent drum 3 at the site of the transfer mechanism 20 is provided.
In this example, the transfer mechanism 20 is a corona charger,
In a state in which the drum 3 having the toner image 25 and the copy paper 21 are overlapped, a charge having a polarity opposite to that of the toner is discharged from the back surface of the copy paper 21 to transfer the toner image 25 from the drum 3 to the copy paper. Transfer to 21. A fixing mechanism 23 such as a heating roller is provided in the transport direction of the copy paper 21.
The toner image transferred on 21 is heat-fixed.

A cleaning mechanism 24 is provided next to the copying mechanism 20 along the rotation direction of the transparent drum, and is configured to remove excess toner remaining on the drum surface by cleaning after toner copying.

For each toner, 100
When continuous copying of sheets was performed, when toner e was used,
Fog occurred, the resolution did not improve more than 2.8 lines / mm, and the image lacked sharpness. When toner f was used, fogging occurred and the resolution was at most 3.0 lines / mm. When toner g was used, there was no fog and the density of the bead portion was satisfactory, and the resolution was also changed at 3.2 to 3.6 lines / mm. Toner h
When f was used, fogging occurred, the density of the solid portion was not sufficient, and the image was poor overall with unevenness.

Further, the color tone of the obtained image is a magenta color and has a vivid color tone, and the toner of the present invention has an advantage that a clear color tone can be obtained without using a colorant.

(Effect of the Invention) According to the toner of the present invention, the photosensitivity per toner particle and the photosensitivity (surface potential decay rate) of the toner layer when a thin toner layer is formed are remarkably improved, and the toner flow is improved. The image quality and charging characteristics are good, the light-attenuated toner is quickly separated from the thin toner layer after image exposure, and a clear image with excellent contrast without causing image fog or image density reduction Can be formed.

In particular, mixing with a magnetic carrier to form a magnetic brush,
A more favorable result can be obtained in the method of forming the thin toner layer and transferring the toner. Further, the toner of the present invention has an advantage that a clear hue image can be obtained without using a colorant.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the specific surface area of zinc oxide and the decay rate of the surface potential of the toner layer. FIG. 2 is an enlarged view of the simultaneous exposure transfer section. FIG. 3 is a schematic view of an apparatus for measuring the transfer sensitivity of the toner of the present invention. FIG. 4 is a diagram illustrating an example of an image forming apparatus to which the toner of the present invention is applied.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-177157 (JP, A) JP-A-60-136752 (JP, A) JP-A-55-81353 (JP, A) JP-A-62 28770 (JP, A) JP 40-9790 (JP, B1)

Claims (4)

(57) [Claims] 1. A fixing resin containing 5 parts by weight per 100 parts by weight of the resin.
A photoconductive toner in which 0 parts by weight or more of an inorganic photoconductive material is dispersed, wherein the inorganic photoconductive material has a specific surface area of 8 to 20 m ² / g, and a fatty acid and a sensitizing dye are adsorbed on the surface. A photoconductive toner. 2. The method of claim 1, wherein the inorganic photoconductive material is zinc oxide.
The photoconductive toner according to claim 1. 3. An organic solvent having a specific surface area of 8 in a fatty acid-capable organic solvent.
A process of immersing an inorganic photoconductive material of from 20 to 20 m ² / g, and a process of adding a fatty acid and a sensitizer to the solution and adsorbing the sensitizer on the surface of the inorganic photoconductive material. . 4. The method according to claim 3, wherein the inorganic photoconductive material is zinc oxide.
A method for producing the photoconductive toner according to the above.