JPH07104618B2 - Toner for electrophotography - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic toner, and more particularly to a toner that develops a clear black color by a combination of colorants.

BACKGROUND ART Conventionally, in electrophotography, US Pat.
As described in JP-B No. 42-23910 and JP-B No. 43-24748, an electrostatic charge is uniformly applied on the photoconductive layer by corona discharge, and an optical image corresponding to the original is formed on it. By exposing, the latent image is formed by extinguishing the electric charge of the exposed portion, and further, the electrostatic latent image thus obtained is attached with a fine powder electrophotographic substance, so-called toner, for development. At this time, the toner is attracted to the electrostatic latent image according to the magnitude of the charge amount on the photoconductive layer to form a toner image having a shade. This toner image is transferred to the surface of a support such as paper or cloth, if necessary, and is permanently fixed to the surface of the support by an appropriate fixing means such as heating, pressure or solvent treatment, and topcoating treatment. Also, if it is desired to omit the toner image transfer step, this toner image can be fixed on the photoconductive layer.

On the other hand, a number of developing methods using a developer such as the toner are also known, and the cascade developing method described in US Pat. No. 2618552, the magnetic brush method described in US Pat. No. 2874063, and the touchdown described in US Pat. Method and other jumping development methods. In particular, a magnetic brush method is known as a typical developing method.

In this magnetic brush method, magnetic particles such as steel and ferrite are used as carriers. The developer consisting of toner and this magnetic carrier is held by a magnet, and the developer is arranged in a brush shape by the magnetic field of this magnet. When this magnetic brush contacts the electrostatic latent image surface on the photoconductive layer, only toner is attracted from the brush to the electrostatic latent image for development.

In addition, in the jumping developing method, a direct current and an alternating electric field are simultaneously applied between the electrostatic latent image surface and the developer carrier to cause the developer to reciprocate between the latent image surface and the carrier. By doing so, development is performed.

These development methods can be used to obtain multicolor color copies as well as conventional black and white copies. That is,
First, light from the original is exposed on the photoconductive layer through a blue filter, and the formed electrostatic latent image is developed with a yellow toner having a complementary color relationship with the filter. Next, similarly, the latent images formed by aligning and exposing the latent image through a green filter and a red filter are developed with magenta toner and cyan toner, respectively. Finally, "blackening" is performed with black toner. The developed four color toners are sequentially transferred to the same support, and the final color copy is obtained by one fixing. Of course, in this color developing method, the order of development is not limited to the order of yellow, magenta, cyan, and black described above, and can be appropriately changed.

Generally, there are two methods such as magnetic brush development method and cascade development method.
When the component development method is applied, the mixing ratio of the carrier in the developer and the toner (for example, colored resin fine powder) is
It is an extremely important factor in terms of development effect. That is, in the magnetic brush developing method, the developer adhering to the magnet slides on the electrostatic latent image and visualizes the latent image with toner. As a result, the toner is gradually consumed from the developer. The ratio of the toner to the carrier decreases (that is, the density of the developer decreases), and the density of the developed image gradually decreases. Therefore, in the two-component developing method, it is necessary to appropriately replenish the toner, but in this case, if the toner is replenished more than appropriate, the density of the image becomes too dark and fog increases. Therefore, it is necessary to accurately detect the density of the developer in order to continuously obtain images with a preferable color tone.

Heretofore, some methods for automatically controlling the concentration of the developer are known. For example, in the method proposed in Japanese Examined Patent Publication No. 38-17245, the colors of the carrier and the toner are made different, and the mixed color density of the developer, which is the mixture of the carrier and the toner, changes as the toner is consumed. By utilizing that
The developer concentration is kept constant by optically detecting the change and controlling the replenishment of the toner to the developer according to the change.

However, this method cannot be used if the color tones of the carrier and toner are similar. In the generally widely used magnetic brush method, black toner in which carbon black and charge control agent are mixed with resin is used as the toner, while as carrier, various iron powders, ferrites (for example, electric field iron) are used. Powder, reduced iron powder, atomized iron powder, magnetite, Fe-Zn ferrite, Fe-Co ferrite), or those whose surfaces are oxidized or surface-treated.

Such diffuse reflectances of the carrier and toner are both small, and the difference is small and the reflected light amount of the developer as a whole is small. Therefore, it is difficult to use the reflected light amount as a developer concentration detecting means. .

The Applicant, as a method for accurately detecting the developer concentration,
Previously, a method for detecting the reflection or transmission density of the developer in the infrared region was proposed (JP-A-53-107853). According to this method, the change of the reflectance depending on the developer concentration, that is, the change of the reflected light amount can be made large, and not only the detection accuracy can be improved, but also the advantage that it can be used not only for the white copy but also for the color copy. is there. However, in this method, since the reflected or transmitted light in the infrared region of the toner is detected, it is not possible to use carbon black, iron black, nigrosine, a dye or the like which has been widely used as a conventional black colorant. However, there is a problem that a colorant having a reflection or a transmission in the infrared region must be used.

As a method for solving such a problem, Japanese Patent Laid-Open No. 48-637
No. 27, JP-A-57-119363, two or more kinds of colorants such as dyes and pigments that reflect or transmit infrared light and are not black are mixed with or mixed with a binder resin in an appropriate amount, or There is a means of using a blackened toner by kneading.

It is possible to obtain a substantially black toner by combining a colorant that is not black in this way, but in order to actually use it as a toner, not only its color tone but also the above-mentioned infrared spectral characteristics, It is essential that all of the electrophotographic properties such as triboelectricity are good. However, such electrophotographic characteristics have not been examined at all in the proposal of the conventional blackening toner described above.

The electrophotographic characteristics that the actual toner should satisfy include:
Various attributes as described below are possible.

(1) The electrophotographic characteristics of the toner should preferably have triboelectricity and fluidity.

(2) Good storage stability without caking or agglomeration during handling or storage.

(3) It has a small environmental dependency in terms of charging.

(4) It must have durability characteristics that will not deteriorate even if it is repeatedly used many times.

(5) To provide a clear image with no bleeding or fog.

Among the above-mentioned electrophotographic characteristics, especially the charging characteristics have a great influence on the environmental characteristics of the toner, the image quality, etc. Therefore, especially the charge controllability is extremely important in selecting the colorant.

In addition, it is necessary to select a colorant that does not easily cause carrier contamination (so-called spent) even by repeated copying and does not bleed to the toner surface and promote toner deterioration due to poor dispersion in the binder resin.

However, according to the study by the present inventors, in the conventional blackened toner (by the combination of a plurality of colorants),
Although some results were obtained with respect to color tone or infrared spectral characteristics, extremely insufficient results were obtained with respect to electrophotographic characteristics such as triboelectric charging characteristics. Therefore, when such a conventional blackened toner is used, it is difficult to obtain a good image at the time of durability, high temperature and high humidity, and low temperature and low humidity.

OBJECT OF THE INVENTION An object of the present invention is to provide an electrophotographic toner containing a colorant capable of reflecting or transmitting light in the infrared region.

Another object is to provide an electrophotographic toner having sufficient charging characteristics.

Still another object is to provide an electrophotographic toner having good environmental stability and having a small difference in charge amount even under low temperature low humidity and high temperature high humidity environments.

Still another object is to provide an electrophotographic toner which is less likely to cause spent of carriers (contamination of carriers) and has excellent durability.

Still another object is to provide an electrophotographic toner having good storage stability.

SUMMARY OF THE INVENTION The inventors of the present invention have not only excellent spectral reflection characteristics as a blackened toner, but also good electrophotographic characteristics including charging characteristics and environmental stability when they are contained in a binder resin. As a result of diligent studies on a colorant that gives a specific derivative obtained by introducing a specific dicarboxylic acid imide-substituted alkyl group (hereinafter sometimes abbreviated as “imido-substituted alkyl group”) into the aromatic nucleus of the copper phthalocyanine skeleton, In the binder resin, it was found that not only suitable spectral reflection characteristics but also excellent charging characteristics are exhibited, and further, this copper phthalocyanine derivative is excellent in combination with an azo compound and a fluorane compound having a specific structure. It has been found that it gives a blackened toner having both infrared spectral reflection characteristics and excellent electrophotographic characteristics.

The toner for electrophotography of the present invention is based on the above findings, and more specifically, a phthalocyanine compound represented by the following formula (1) and an azo compound represented by the following formula (2) in a binder resin. And a fluoran compound represented by the following formula (3).

(In the formula (1), X ₁ , X ₂ , X ₃ and X ₄ are, respectively, Or -H (except when all are -H). A
And A ₁ each represent an alkylene group having 1 to 5 carbon atoms. ) (In the formula (2), R ₁ and R ₃ are respectively -COOH,
Represents --OH, --NO ₂ , --Cl or --H, R ₂ is --SO ₃ Na or-
H is shown. ) (In the formula (3), R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each represent —H or —C _n H _{2n + 1} (n = 1, 2, 3), X
Represents Cl or SO ₃ H. According to the experiments by the present inventors, in the phthalocyanine derivative (1) which is an essential constituent component of the toner of the present invention, when the substituent on the copper phthalocyanine skeleton is other than the imide-substituted alkyl group, excellent spectral reflection characteristics are obtained. It was not possible to obtain a blackened toner having both excellent charging characteristics.

In the above-mentioned phthalocyanine derivative (1) used in the present invention, as the number of substitutions of the imide-substituted alkyl group increases, the charging property as the electrophotographic property is remarkably improved. It is presumed that this is because the combination of the functional groups in the above-mentioned substituents contributes as a whole to a factor that significantly improves the charging characteristics of the copper phthalocyanine skeleton.

In the toner of the present invention, the characteristics of the copper phthalocyanine derivative (1) are combined with the azo compound (2) and the fluoran compound (3) having a remarkable charge promoting action, and these three colorants are used. Show good affinity with each other and are well dispersed in the binder resin,
It is presumed that a blackened toner having not only the above-mentioned spectral characteristics and charging characteristics but also little environmental dependence, and excellent durability and storage stability can be obtained.

On the other hand, in the conventional blackened toner, it is presumed that these characteristics of the toner as a whole were insufficient because the spectral characteristics and charging characteristics of the cyan colorant were not good. Further, in such a conventional toner, since the mutual affinity of the colorants is low and the compatibility of the colorants with the binder resin is low, the colorant that is poorly dispersed is exposed on the toner surface. It is presumed that such toner spent, deterioration of durability, deterioration of storage stability, and toner fusion to the photosensitive drum occurred.

Hereinafter, the present invention will be described in more detail. In the following description, “part” and “%” representing the quantitative ratio are based on weight unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION The toner of the present invention includes a binder resin, a phthalocyanine compound represented by the formula (1), an azo compound represented by the formula (2), and a fluorane represented by the formula (3). And a system compound as an essential constituent.

In the present invention, a compound represented by the following structural formula (1) is used as the imide-substituted alkylphthalocyanine compound.

In the above formula (1), X ₁ , X ₂ , X ₃ and X ₄ are respectively Or represents -H (provided that not all X ₁ to X ₄ are -H at the same time). A and A ₁ are respectively
An alkylene group having 1 to 5 carbon atoms (preferably 1 to 2) is shown.

Specifically, X ₁ to X ₄ in the above formula (1) are preferably the following functional groups.

In the above formula (1), the number of substituents of the imide-substituted alkyl group (that is, the phthalimide-substituted alkyl group and / or the maleinimide-substituted alkyl group) is determined by the synthetic reaction of the substituted phthalocyanine compound (1) (for example, the substitution reaction for a benzene ring). It can be changed by the reaction charge amount in (1) and other reaction conditions (solvent, temperature conditions, etc.), whereby a substituted phthalocyanine compound (1) having a different number of substituents is obtained. In the present invention, the phthalocyanine compound (1) is used in which the imide-substituted alkyl substituent is substituted on the copper phthalocyanine skeleton in an amount of 1 to 4, preferably 1 to 2.

The number of substituents of the above-mentioned substituent is, for example, nuclear magnetic resonance absorption (NM
It has been confirmed by instrumental analysis methods such as R).

In the present invention, such a substituted phthalocyanine compound (1) may be used alone, and if necessary, as a mixture of two or more kinds of compounds having different kinds of substituents, their substitution positions, or the number of substituents. You may use.

Next, the azo compound (2) and the fluoran compound (3) that exhibit good spectral characteristics and electrophotographic characteristics when combined with the substituted phthalocyanine compound (1) will be described.

These compounds (2) and (3) have a remarkable effect of accelerating the charging of the toner. By selecting a binder resin having a charge controllability, or a combination with a charge control agent or a carrier, positive or negative The absolute amount can be applied to either of the charge amounts, but the effect of increasing the negative charge amount is particularly remarkable.

In the present invention, a compound represented by the following formula (2) is used as the azo compound.

In the above formula (2), R ₁ and R ₃ are —COOH and —O, respectively.
H, -NO _2, shows a -Cl or -H, preferably a -COOH or -H.

R ₂ represents —SO ₃ Na or —H, and preferably —H.

As such an azo compound (2), a known azo dye or pigment can be used as it is, but an azo dye, particularly CI Solvent Yellow 16 (Solvent Yellow).
16), CI Solvent Yellow 19, CI Solvent
Yellow 21, CI Solvent Orange 5 (Solvent Or
yellow to orange oil-soluble azo dyes such as ange5) and CI solvent orange 6 are preferably used in combination of two or more kinds as necessary.

On the other hand, the fluoran compound is represented by the following formula (3)
The compound shown by is used.

In the formula (3), R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each represent —H or —C _n H _{2n + 1} (n = 1, 2, 3),
It is preferably -H or -C ₂ H _5.

X represents Cl or SO ₃ H, but Cl is preferable.

As such a fluoran compound (3), known dyes and pigments can be used as they are, but fluoran dyes, particularly CI Basic Red 1 (Basis Re
d 1), CI Basic Violet 10 (Basic Viole
Red to purple basic fluorane dyes such as t10) are preferably used in combination of two or more kinds, if necessary.

In the present invention, the above-mentioned substituted phthalocyanine compound (1), azo compound (2), and fluorane compound (3) are each 0.5 to 0.5 parts with respect to 100 parts of the binder resin.
It is preferable to add 10 parts (more preferably 0.7 to 8.5 parts).

If the compounding amount of any one of the compounds (1), (2) or (3) is less than 0.5 part, it is difficult to obtain a substantial black color due to the combination of these compounds, and sufficient image density is obtained. I can't. On the other hand, if one of the above
If it exceeds 10 parts, the toner charge amount greatly depends on the environment, and further, the spent of the toner on the carrier during endurance is accelerated.

The total amount of these compounds (1), (2) and (3) compounded is preferably about 1.5 to 20 parts per 100 parts of the binder resin.

In the present invention, if necessary, in order to adjust the color to some extent, known direct dyes other than the compounds (1), (2) and (3) within a range that does not impair the object of the present invention,
It is also possible to use disperse dyes, acid dyes, basic dyes, oil-soluble dyes, or pigments as auxiliary colorants.
The addition amount (total amount) of these auxiliary colorants is preferably 1/2 or less (more preferably 1/3 or less) of the total amount of components constituting the toner other than the binder resin.

The binder resin used in the toner of the present invention can be used without particular limitation, including known ones.
Polystyrene, polychlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer , Styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid burch copolymer, styrene-
Octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate) Copolymers, styrene-phenyl methacrylate copolymers, etc.), styrene-α-chloromethyl acrylate copolymers, styrene-acrylonitrile-acrylic acid ester copolymers and other styrene resins (including styrene or styrene substitutes) Homopolymer or copolymer); vinyl chloride resin, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin,
Polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin and the like can be used alone or in combination of two or more kinds.

Among the above resins, in the present invention, styrene-
(Meth) acrylic acid resin, styrene- (meth) acrylic acid ester resin, and polyester resin are preferably used.

Further, in the present invention, a carboxylic acid component (for example, fumaric acid, which is composed of any one or more of a diol component represented by the following formula and a divalent or higher carboxylic acid, or an acid anhydride thereof, or a lower alkyl ester thereof: Maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid,
A polyester resin obtained by copolycondensation with (pyromellitic acid) is particularly preferably used.

(In the formula, R is an ethylene or propylene group, and x, y
Are each an integer of 1 or more, and the average value of x + y is 2 to 10. On the other hand, as a carrier used in combination with the toner of the present invention as necessary, either a substance having magnetism or a substance not having magnetism can be used.
Iron, steel, ferrite, Ba-Fe ferrite, Cu-Fe ferrite, Zn-Fe ferrite, Sr-Fe ferrite, and chromium,
Cerium or magnesium oxide, zircon, silicon, silicon dioxide, or the like is used. These substances have an average particle size of 20-100 μm, preferably 25-70 μm,
It is more preferably used as particles of 30 to 65 μm.

If desired, the toner of the present invention may be mixed with various additives such as a charge control agent, a lubricant, fine powder silica, PVDF (polyvinylidene fluoride) powder and the like.

In the toner of the present invention, the substituted phthalocyanine compound (1), the azo compound (2), and the fluorane compound (3) described above are kneaded and dispersed in a binder resin according to a conventional method,
By performing pulverization (further classification if necessary), particles having a volume average particle diameter of preferably 5 to 15 μm are obtained. At the time of the above-mentioned kneading, from the viewpoint of improving the mixing properties of the colorants with each other or the dispersibility of these into the binder resin, the above-mentioned three kinds of compounds (1), (2) and (3) were first thoroughly mixed. It is preferable to disperse it in the binder resin later.

The triboelectric charge amount of the toner of the present invention thus obtained can be measured, for example, as follows (blow-off method).

FIG. 1 is a schematic perspective view showing an example of the triboelectric charge amount measuring device.

Referring to FIG. 1, let's measure the amount of triboelectrification in a metal measuring container 2 having a conductive screen 1 of 400 mesh (a size that does not allow passage of magnetic particles) at the bottom). Add about 4 g of the developer, and put on the lid 3 made of metal. At this time, the weight of the entire measuring container 2 (including the lid 3) is weighed and designated as W ₁ (g). Next, using the suction device 4 (at least the portion in contact with the measurement container 2 is made of an insulator), suction is performed from the suction port 5, and the air volume control valve 6 is adjusted to adjust the pressure indicated by the vacuum gauge 7 to 70 mmHg. To do.

In this state, suction is sufficiently performed (for about 1 minute) to remove the toner by suction. Directly read the potential of the electrometer 8 at this time, and
(Bolt). Here, 9 is a condenser, and this capacitance is C (μF). In addition, the measurement container 2 after suction
Weigh the whole and set it to W ₂ (g). In this case, the triboelectric charge amount T (μC / g) of the toner in the developer is calculated by the following formula.

EFFECTS OF THE INVENTION According to the present invention as described above, the binder resin contains a specific imide-substituted alkylcopper phthalocyanine compound, an azo compound having a specific structure, and a specific fluorane compound. A blackened toner having excellent spectral reflection characteristics and charging characteristics can be obtained.

The toner of the present invention, based on the characteristics of the phthalocyanine compound and the like, exhibits not only good electrophotographic characteristics such as charging characteristics but also excellent spectral characteristics particularly in the infrared,
While providing a good black image, accurate detection of developer concentration is extremely easy.

Therefore, the toner of the present invention is suitably used as a black toner for color electrophotography, in which a developing method using a two-component developer is used, and particularly accurate control of developer concentration is extremely important.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 The ingredients of the above formulation were mixed thoroughly to give 4.6 parts by weight of a black mixture. To this black mixture (4.6 parts) was added 100 parts by weight of a polyester resin obtained by condensing propoxylated bisphenol and fumaric acid, and further sufficiently premixed using a Henschel mixer, and then melt-kneaded and kneaded by a roll mill. It was a thing. The kneaded product was cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The finely pulverized product obtained is further classified to
20 μm was selected, and 0.3 part of finely powdered silica was externally added (mixed) to obtain a blackened toner of the present invention.

100 parts by weight of this toner and Fe-Cu-Z coated with fluororesin
A developer was prepared by mixing 900 parts by weight of n-ferrite (average particle size: 50 μm, carrier particles).

FIG. 2 shows the spectral diffuse reflectance of this developer in the visible and infrared regions, and the spectral diffuse reflectance of the fluororesin-coated ferrite particles used as a carrier. This second
It can be understood from the figure that the difference in reflectance between the carrier particles and the toner of the present invention is large in the infrared region.

The developer obtained as described above was applied to a color electrophotographic copying machine as shown in the schematic side sectional view of FIG. 3, and an image forming test was conducted.

Referring to FIG. 3, the electrostatic latent image formed on the photoconductor drum 10 having the CdS photoconductor having the positive charging property is the developing device.
The developed toner powder image was transferred by the transfer corotron 21 to the transfer material visualized by the developer in 16a and already held on the transfer drum 19 by the gripper 20.

Then, the transferred image was fixed and fixed on the transfer material by using a fixing means to obtain a copy.

A durable image forming test was conducted using the above copying machine.
A clear image without fog was obtained even after running for 10,000 sheets. In addition, the melting point of the toner did not reach the drum 10, and at this time, the ratio of the initial charge amount of the developer to the charge amount after 10,000 sheets (charge amount after 10,000 sheets / initial charge amount) was 0.9. Therefore, there was almost no change in the charge amount.

Low temperature and low humidity (15 ℃, 10% RH), normal temperature and normal humidity (23 ℃, 60% RH) and high temperature and high humidity (32.5 ℃, 85% RH) of this developer,
FIG. 4 shows the change in charge amount under the conditions. Looking at this Figure 4, despite such extreme environmental changes,
It will be understood that the developer containing the toner of the present invention is electrostatically stable.

The triboelectric charge amount in FIG. 4 is a value measured by the blow-off method described above after the toner concentration in the developer is 10% and the toner is left in each environment for 2 days.

Example 2 Instead of the polyester resin of Example 1, a styrene-diethylaminoethyl methacrylate resin (copolymerization ratio 9: 1,
A blackened toner and a developer of the present invention were obtained in the same manner as in Example 1 except that the weight average molecular weight of 12000) was used.

A durable image forming test was conducted in the same manner as in Example 1 except that this developer was used and the apparatus of FIG. 3 equipped with an OPC (organic photoconductor, negatively chargeable) photosensitive drum 10 was used.
Good images were obtained even after 15,000 sheets.

The environmental dependence of the change in the charge amount of the developer is shown in the graph of FIG.

Example 3 Instead of the black mixture of Example 1 (4.6 parts), each component of the above formulation and phthalocyanine green 0.1 as a tint adjusting agent were used.
A blackened toner and a developer of the present invention were obtained in the same manner as in Example 1 except that a black mixture (13.2 parts) obtained by mixing the same was used.

Using this developer, repeated copying was performed under high temperature and high humidity in the same manner as in Example 1, and 20,000 copies were made. Image bleeding and fog did not change from the initial stage, and a good image was obtained.

Comparative Example 1 A toner was prepared in the same manner as in Example 1 except that 5 parts by weight of carbon black was used in place of the black mixture of Example 1 (4.6 parts) to obtain a developer.

The spectral diffuse reflectance of this developer is shown in FIG. It can be seen that the above reflectance is small even in the visible and infrared regions and is not suitable for detecting the developer concentration by the reflection concentration.

Comparative example 2 A toner and a developer were prepared in the same manner as in Example 1 except that the black mixture (15.2 parts) obtained by mixing the above three kinds of colorants was used in place of the black mixture (4.6 parts) in Example 1. Obtained.

In the measurement by the spectral reflectance measurement, a sufficient reflectance of infrared light could be obtained. However, when a durability image forming test similar to that in Example 1 was performed, fog on the image was remarkably increased after 8,000 sheets. It became impossible for practical use.

In this developer, the absolute value of the charge amount was considerably low, ie, -3.8 μC / g at 8,000 sheets, compared to the initial charge amount of -11.3 μC / g.

From this, it is presumed that the toner of Comparative Example 2 was not given a sufficient charge amount for durability, and therefore the fog was remarkably increased.

Further, FIG. 4 shows changes in the charge amount of the toner under three environments such as normal temperature and normal humidity. Referring to FIG. 4, the toner of Comparative Example 2 gives an almost appropriate charge amount value at room temperature and normal humidity, but a significant difference from the charge amount under low temperature and low humidity and high temperature and high humidity conditions is observed. The toner was unstable in terms of charge.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a triboelectric charge amount measuring device used in the present invention, FIG. 2 is a graph showing the spectral reflection characteristics of the toner etc. obtained in Example 1, and FIG. 3 is an example. FIG. 4 is a schematic side sectional view showing the outline of the color electrophotographic copying machine used, and FIG. 4 is a graph showing the charge amount of the toners of Examples and Comparative Examples under each environment. 1 ... Conductive screen 2 ... Measuring container 3 ... Metal lid 4 ... Suction machine 5 ... Suction port 6 ... Air flow control valve 7 ... Vacuum meter 8 ... Electrometer 9 ... Condenser 10 ... Photosensitive drum 16 Development unit 19 Transfer drum 20 Gripper 21 Transfer corotron 22 Separation claw Representative diagram: Fig. 2

Front page continued (72) Inventor Ryoichi Fujita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroyuki Suematsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-58-203455 (JP, A) JP-A-57-119363 (JP, A)

Claims (1)

[Claims] 1. A binder resin containing a phthalocyanine compound represented by the following formula (1), an azo compound represented by the following formula (2) and a fluorane compound represented by the following formula (3). An electrophotographic toner characterized by the above. (In the formula (1), X ₁ , X ₂ , X ₃ and X ₄ are, respectively, Or -H (except when all are -H). A
And A ₁ each represent an alkylene group having 1 to 5 carbon atoms. ) (In the formula (2), R ₁ and R ₃ are respectively -COOH,
Represents --OH, --NO ₂ , --Cl or --H, R ₂ is --SO ₃ Na or-
H is shown. ) (In the formula (3), R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each represent —H or —C _n H _{2n + 1} (n = 1, 2, 3), X
Represents Cl or SO ₃ H. )