JP2000066451A - Yellow toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the dispersibility of a colorant in a toner and to attain good color reproducibility and the stabilization of electrostatic charge by using a bonding resin having a specified acid value and a specified compd. SOLUTION: This yellow toner has yellow toner particles contg. a bonding resin and a yellow colorant. The bonding resin is based on a polyester resin and has 2.0-30.0 mgKOH/g acid value. The yellow colorant has a compd. of the formula, the primary particles of the yellow colorant have a major to minor axis size ratio of <=3 and the number average particle diameter of the yellow colorant present in the yellow toner particles is 0.1-0.5 μm. The yellow toner contains the compd. of the formula in 1-15 pts.wt., preferably 2-12 pts.wt., further preferably 3-10 pts.wt. based on 100 pts.wt. bonding resin. The toner preferably contains a metallic compd. of an arom. carboxylic acid deriv.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a yellow toner for developing an electrostatic image in electrophotography, electrostatic recording and electrostatic printing or a yellow toner for forming a toner image in a toner jet type image forming method. With regard to
In particular, the present invention relates to a yellow toner having a wide color reproducibility of a color image, and having excellent offset resistance and low-temperature fixability.
Further, the present invention relates to a yellow toner having excellent environmental stability and durability stability. Further, the present invention relates to a yellow toner having excellent transparency.

[0002]

2. Description of the Related Art In recent years, full-color copying machines have begun to attract attention. In particular, digitized full-color copiers are receiving attention and are being widely deployed in the market.

[0003] Color image formation by full-color electrophotography generally reproduces colors using three primary color toners of three colors, yellow, magenta, and cyan, or four colors including black.

According to the general color image forming method, an electrostatic latent image is formed on a photoconductive layer through a color separation light transmitting filter having a complementary color relationship with the color of toner of light from a document. Next, the toner is held on a support through development and transfer steps. The above-described steps are sequentially performed a plurality of times, and while the registration is being performed, the toner is superimposed on the same support,
A final full-color image can be obtained by fixing only once.

In such a color electrophotography method in which development is performed a plurality of times and several types of toner layers of different colors are superposed on the same support as a fixing step, the fixing characteristics that the color toner should have Is a very important factor.

That is, the fixed color toner must be a color toner having transparency that does not hinder the toner layers of different colors below the toner layer and having a wide color reproducibility.

[0007] Furthermore, the demand for the quality of full-color copied images is increasing more and more. For general users who have considered printing, full-color copied images are not yet at a satisfactory level, and they want a level closer to printing and a level closer to photography. That is, a toner having an image density output covering a wide dynamic range from a high density to a low density, and an OHP image having the same transparency as a print, include a solid image having a large image area in a copied image, uniformity of a halftone image, and an image density output covering a wide dynamic range from high density to low density. It has been demanded.

[0008] The shortest and preferred method of meeting these requirements is to first improve the dispersibility of the colorant present in the toner.

JP-A-4-39671, JP-A-4-39671
JP-A-39672 and JP-A-4-242275 disclose a method for producing a toner while applying heat and pressure in a kneader. This method is preferably used for dispersing a colorant, Is broken by a strong kneading load, and partial reduction of the molecular weight in the polymer is promoted. Therefore, a high-temperature offset easily occurs in the fixing process. Especially in color copying, the latitude of high-temperature offset resistance is much more severe than that of black-and-white toner because three or four color toners are fixed in layers.
Slight molecular breaks in the polymer easily cause hot offset.

On the other hand, in the conventional sharp melt resin having excellent color reproducibility, since the so-called kneading load at the time of kneading the resin and the colorant does not increase, the power for dispersing the colorant is insufficient. In particular, when a pigment having high cohesiveness is used as a coloring agent, the tendency is remarkable, and good dispersion of the coloring agent cannot be expected.

Therefore, the design of the resin and the selection of the colorant have a very significant meaning so as to satisfy both the offset resistance and the fixing property and also the dispersibility of the colorant.

[0012] Today, there are many known colorants for yellow toner in the art. For example, JP-A-2-207273 discloses Solvent Yellow 112, JP-A-2-207274 discloses Solvent Yellow 160, and JP-A-8-36275 describes Solvent Yellow 162. JP-A-50-62442 discloses a benzidine yellow pigment, JP-A-2-87160 discloses a monoazo yellow toner, and JP-A-2-208.
No. 662 discloses pigment yellow 120, 151,
154, 156 and the like are described.

However, conventionally known colorants for yellow toner have many problems. For example, dye-based colorants generally have excellent transparency,
Poor light fastness and poor storage stability of images.

On the other hand, the above-mentioned pigment group is excellent in light resistance as compared with dyes, but is, for example, a quinacridone pigment used for magenta toner or a copper phthalocyanine pigment used for cyan toner. In comparison with the above, there is still a problem in light fastness, and in a long-time light exposure test, a problem such as color fastness or noticeable change in hue has occurred.

Further, yellow pigments having excellent light resistance and heat resistance are available in addition to the above-mentioned pigments. However, on the contrary, the opacity is too strong, and the transparency is extremely reduced. there were.

Japanese Patent Publication No. 2-37949 discloses a disazo compound having excellent light resistance and a method for producing the same. This is a group of compounds represented by Pigment Yellow 180 and is one of the azo pigments which not only has excellent light resistance and heat resistance but also meets ecological requirements.

Pigment Yellow 180 is disclosed in JP-A-6-230607 and JP-A-6-230607.
JP-A-266163 and JP-A-8-262799 describe that a toner using the above-mentioned pigment has poor coloring power and, in addition, transparency is not always good. Improvement was urgently needed.

On the other hand, JP-A-8-209017 discloses an electrophotographic toner in which the pigment is finely divided to improve the specific surface area of the pigment and to improve the transparency and the coloring power in order to solve the above problem. Have been. However, when the pigment classified as Pigment Yellow 180 is made finer, the self-aggregation property of the pigment is inevitably strong, so that the dispersibility in the binder resin constituting the toner is insufficient.
According to our investigation, it has been difficult to stabilize the charging of a toner having poor dispersibility of the colorant, and there have been problems such as fog and toner scattering.

Japanese Patent Publication No. 2632423 describes a toner in which a group of disazo yellow pigments is kneaded and dispersed in a resin.

The above toner is prepared by kneading and dispersing a hardly dispersible compound to an average particle diameter of 0.2 μm or less.
Although the clarity and clarity of the hue and the improvement of the transparency were achieved, there is still room for improvement when viewed as a full-color yellow toner.

On the other hand, JP-A-5-34978 discloses that
There is a description of a coloring composition for image recording obtained by kneading a pigment aqueous presscake and a hot-melt resin binder. In Examples, C.I. I. Pigment Yellow 1
A high-concentration colored composition using 28 aqueous presscakes and a styrene-methacrylic copolymer resin is introduced. However, in our investigations, the level of pigment dispersibility was by no means good, and furthermore, commercial C.I.
I. The toner using Pigment Yellow 128 is not stable in charging, and has problems such as durability, light density and fog.

On the other hand, when a two-component developer comprising a toner and a carrier is used as the developer, the toner is charged to a required charge amount and charge polarity by friction with the carrier, and the electrostatic attraction is used. This is for developing an electrostatic image. Therefore, in order to obtain a good visible image, it is mainly necessary that the toner has good triboelectric charging properties.

In order to solve the above-mentioned problems or to prevent the chargeability of the toner from being influenced by the chargeability of the colorant itself, the search for the carrier core material and the carrier coat material and the determination of the coat amount are carried out. A lot of research has been conducted to achieve excellent triboelectricity in the materials constituting the developer, such as optimization, investigation of charge control agents and fluidity imparting agents added to the toner, and improvement of the base binder. ing.

In recent years, there has been an increasing demand in the market for high definition and high image quality of copying machines or printers. In the technical field, attempts have been made to achieve high image quality color by reducing the particle size of color toner. ing. As the particle size of the toner becomes smaller, the surface area per unit weight increases, the charge amount of the toner tends to increase, and the image density tends to be low and the durability tends to deteriorate. In addition, since the charge amount of the toner is large, the adhesive force between the toner particles is strong, the fluidity is reduced, and problems are likely to occur in the stability of toner replenishment and the provision of tribo of the replenished toner.

Further, in the case of a color toner, since it does not contain a black conductive material such as a magnetic substance or carbon black, there is no portion that leaks the charge, and the charge amount generally tends to be large. This tendency is more remarkable especially when a polyester binder having a high negative charging performance is used.

In the art today, polyester resins are widely used as binder resins for color toners. However, color toners having polyester resins are generally easily affected by temperature and humidity, and the charge amount under low humidity is generally low. Excessive,
Problems such as insufficient charge amount under high humidity tend to occur, and development of a color toner having a stable charge amount even in a wide range of environments is expected.

It is known that the charge of the toner varies greatly depending on the degree of dispersibility of the colorant in the binder resin and the charge characteristics of the colorant itself as described above. And toner scattering, and various problems such as toner spent on a carrier, toner filming on a drum, and contamination of a fixing roller are caused. Therefore, improvement of the dispersibility of the colorant is an important technical issue other than the aspect of color reproducibility.

[0028]

SUMMARY OF THE INVENTION An object of the present invention is to provide a yellow toner which has solved the above-mentioned problems.

That is, an object of the present invention is to provide (1) good fixability and color mixing in full-color copying,
(2) Sufficient triboelectricity, (3) High gloss, which significantly enhances image quality, (4) High-temperature offset is sufficiently prevented, the feasible temperature range is wide, (5) Repeated fixing paper passing (6) no toner is fused to the inside of the developing device, that is, to parts such as a developing sleeve, a blade, and a coating roller, and (7) a photoreceptor. No filming on the surface, (8) good dispersibility of the colorant, (9) high coloring power, high image density, (10) high chroma, excellent transparency, (11) An object of the present invention is to provide a yellow toner having excellent light fastness and not fading.

[0030]

The above object is achieved by the following constitution.

That is, the present invention relates to a yellow toner having yellow toner particles containing at least a binder resin and a yellow colorant, wherein the binder resin is mainly composed of a polyester resin, and the acid value of the binder resin is 2.0 to 30.0 mgKOH / g, and the yellow colorant is
The following formula (I)

[0032]

[Outside 2] Wherein the primary particles of the yellow colorant have a ratio of the major axis to the minor axis of 3 or less, and the number average diameter of the yellow colorant present in the yellow toner particles is 0.1.
1 to 0.5 μm.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the coloring agent used in the present invention will be described.

The pigment represented by the formula (I) belongs to a condensed disazo pigment, and C.I. I. Pigment Yellow
w128. As such, it is already known as a colored body for plastics, but it is a hardly dispersible pigment, and therefore has not been used much in the art.

The present inventors have conducted intensive studies to improve the dispersibility of the compound (I), and found that a resin having a polyester resin as a main component and an acid value of 2.0 to 30.0 mgKOH / g was used as a binder resin. When a colorant having a ratio of the major axis to the minor axis of the primary particle diameter of 3 or less is used as a colorant,
They have been found to provide excellent dispersibility and function as a full-color yellow toner. Further, they have found that excellent chargeability can be obtained when a resin containing the above polyester resin as a main component is used as a binder resin and the colorant of the compound (I) is dispersed.

That is, the compound (I) has a function of stabilizing the charge amount of the toner, and prevents the frictional charge amount of the toner from becoming excessive in a low-temperature and low-humidity environment. A reduction in the amount of triboelectric charging of the toner under the environment is suppressed. In particular, when a resin containing a polyester resin having an acid value as a main component is used as the binder resin, the effect of the compound (I) is more remarkable. That is, it functions not only as a colorant but also as a charge stabilizer. The reason is that the carboxyl group or hydroxyl group at the terminal of the molecular chain of the polyester resin and the carbonyl group or imino group of the compound (I) are partially hydrogen-bonded or electrostatically bonded, and as a result, (i ) Adsorption of moisture to the carboxyl group or hydroxyl group at the terminal of the molecular chain of the polyester resin is suppressed, and a decrease in the triboelectric charge amount of the toner can be suppressed even under a high-temperature and high-humidity environment. Since the polar groups such as carboxyl group or hydroxyl group at the terminal of the molecular chain are reduced, it is presumed that it is possible to suppress the toner from having an excessively high triboelectric charge even in a low-temperature and low-humidity environment.

In addition, the interaction between the polyester used in the present invention and the carbonyl group, imino group and the like in the compound (I) enhances the adhesion between the resin and the compound (I). Will be surrounded by the resin,
It is considered that the colorant was stabilized in the resin in a state close to the primary particles, effectively working to prevent re-aggregation of the colorant, and contributing to stabilization of charging.

Further, when the toner of the present invention is used as a negatively chargeable toner, the terminal —CF ₃ and —Cl groups of the compound (I) function effectively, and as a result, the charge in the toner is reduced. The property shows a stabilizing tendency, and in addition, the charge amount distribution becomes very sharp and uniform.

The yellow toner of the present invention containing the compound represented by the formula (I) as a yellow colorant shows a greenish yellow and has preferable spectral characteristics as a yellow toner for forming a full-color image. Further, the yellow toner containing the compound represented by the formula (I) has high lightness and high chroma. The reproducibility of human flesh color is important in a full-color image. However, when a yellow toner containing the compound represented by the formula (I) is used, human flesh color can be well reproduced, and the overhead projector (OHP) Even when a color image formed on the OHP sheet is projected, the transparency is excellent.

The commercially available yellow pigment (CI Pigment Yellow 128) represented by the formula (1) is usually a needle-like crystal having primary particles whose average value of the ratio of the major axis to the minor axis is larger than 3.0. It has a morphology and contains many primary particles having a large major axis. Such a yellow pigment is difficult to disperse even when melt-kneaded with a binder resin, and it is difficult to produce a highly transparent kneaded material.

As described above, in the system described in JP-A-5-34978, which uses an aqueous press cake of pigment and a resin binder which is heat-meltable, it may be possible to suppress the aggregation of the pigment as much as possible. In the case of a pigment whose primary particles have a long major axis, high transparency required for a full-color toner cannot be obtained.

In the present invention, the coloring agent represented by the compound (I) is subjected to a fine treatment so that the ratio of the major axis to the minor axis of the primary particles is 3.0 or less, and the particles are uniformly bound. When dispersed in a resin, a clear hue image is obtained, and the charge is stabilized. The ratio of the major axis to the minor axis is preferably 2.5 or less, more preferably 2.0 or less. In the present invention, there is no particular reference to the details of the pigment refining treatment.

Further, the compound (I) in the toner used in the present invention has a number average diameter of 0.1 to 0.5 μm,
Preferably 0.4 μm or less, more preferably 0.3 μm
The following is desirable.

When the number average particle size of the compound (I) in the toner is larger than 0.5 μm, the dispersibility of the pigment is not at a sufficient level. Even if an agent is used, the desired transparency cannot be obtained.

Basically, it is considered that a coloring agent having a fine particle diameter smaller than 0.1 μm does not adversely affect light reflection and absorption characteristics. Colorant particles of less than 0.1 μm contribute to good color reproducibility and transparency of OHP sheets with fixed images. On the other hand, if there are many colorants having a particle size larger than 0.5 μm, the brightness and color of the projected image on the OHP sheet tend to be reduced.

Further, if a large amount of a coloring agent having a particle size larger than 0.5 μm is present, the yellow coloring agent is inevitably detached from the surface of the yellow toner particles, which easily causes various problems such as fog, drum contamination and poor cleaning. . Further, when such a yellow color toner is used as a two-component developer, a problem such as carrier contamination is caused, and it is difficult to obtain a stable image in multi-sheet durability. Naturally, good color reproducibility cannot be expected, and uniform chargeability is hardly obtained.

In the present invention, the yellow toner contains the compound represented by the formula (I) in an amount of 1 to 15 parts by weight, preferably 2 to 12 parts by weight, more preferably 3 to 10 parts by weight per 100 parts by weight of the binder resin. It is good to contain.

When the content of the compound represented by the formula (I) is 15
When the amount is more than the weight part, the transparency is lowered, and in addition, the reproducibility of the intermediate color represented by the human skin color is also easily lowered. Further, the stability of the chargeability of the toner decreases, and it becomes difficult to obtain a desired charge amount.

When the content of the compound represented by the formula (I) is less than 1 part by weight, it is difficult to obtain a desired coloring power, and it is difficult to obtain a high quality image having a high image density.

Further, the yellow toner of the present invention containing the compound (I) is hardly discolored and has excellent weather resistance.

In the present invention, the toner preferably contains a metal compound of an aromatic carboxylic acid derivative. This not only functions as a charge control agent, but also contributes to improving the dispersibility of the compound (I), and further enhances the transparency of the toner.

The details will be described below.

The reason why the metal compound of the aromatic carboxylic acid derivative improves the dispersibility of the compound (I) is not clear, but a partial crosslinking reaction is caused by the interaction between the polyester resin and the metal compound of the aromatic carboxylic acid derivative. By increasing the share of the colorant during advance kneading,
This achieves an improvement in the dispersibility of the hardly dispersible compound (I), and can also contribute to an improvement in the anti-offset property on the high temperature side while maintaining the rapid melting property on the low temperature side.

In addition, the metal skeleton of the aromatic carboxylic acid derivative and the partial skeleton of the compound (I).

[0055]

[Outside 3] Interacts as described below to stabilize the dispersion by surrounding the compound (I) with a metal compound in the toner.

[0056]

[Outside 4]

Thus, the compound (I), the binder resin, and the metal compound interact with each other, and the effect of the present invention can be made more remarkable. Thereby, it is also effective in preventing toner filming on the surface of the photoreceptor and toner spent on the surface of the carrier.

Furthermore, the present invention is also effective in preventing the detachment of the pigment from the toner surface, and is effective in preventing the fixing roller from being stained.

Examples of the metal compound of the aromatic carboxylic acid derivative include a metal complex of salicylic acid, a metal salt of salicylic acid, a metal salt of alkyl salicylic acid, a metal complex of alkyl salicylic acid, a metal salt of dialkyl salicylic acid, a metal complex of dialkyl salicylic acid, Examples thereof include metal salts of diols, metal complexes of aromatic diols, metal salts of aromatic dicarboxylic acids, and metal complexes of aromatic dicarboxylic acids.

In the present invention, a metal compound of dialkylsalicylic acid is preferred, and a metal compound of di-tert-butylsalicylic acid is particularly preferred. As the metal element, aluminum, gallium, magnesium, calcium, titanium, chromium, zinc, zirconium, hafnium and the like are preferable, and aluminum and zirconium are particularly preferable.
It is preferable in terms of stabilization of charging, stabilization of dispersion of compound (I), and compatibility with resin. Compounds such as zinc cannot exert sufficient effects on improving the dispersibility of the pigment and stabilizing the charge.
The effect of the present invention cannot be maximized.

When these metal compounds are contained in the yellow color toner particles, the content thereof is in the range of 1 to 10 parts by weight, preferably 2 to 8 parts by weight per 100 parts by weight of the binder resin. Is preferred. When the amount is less than 1 part by weight, not only does not function very much as a charge control agent, but good pigment dispersibility cannot be achieved. On the other hand, when the amount is more than 10 parts by weight, the crosslinking proceeds excessively, and the fixability as a toner is impaired.

When a metal compound is used in the above-mentioned content, the initial variation of the charge amount is small, and the absolute charge amount required at the time of development is easily obtained. As a result, image quality such as fogging and image density reduction is preferred, which is preferable.

In the present invention, if necessary, other charge control agents may be used in combination.

In the present invention, as a binder resin, a polyester resin is used as a main component. When used as a binder resin for a toner, a polyester resin has excellent fixability and is suitable for a color toner.

However, the polyester resin has a strong negative charging ability and tends to be excessively charged.
By using the compound (I), the adverse effect is improved, and an excellent yellow toner is obtained.

In particular, the following formula (II)

[0067]

[Outside 5] (Wherein, R represents an ethylene group or a propylene group, x and y each represent an integer of 1 or more, and the average value of x + y is 2 to 10). A diol component comprising a bisphenol derivative or a substituted product thereof represented by the formula: a divalent or higher carboxylic acid, a divalent or higher carboxylic acid anhydride, and 2
Copolycondensation with a polycarboxylic acid component selected from lower alkyl esters of carboxylic acids having a valency of at least one (eg, fumaric acid, maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid) Polyester resins are more preferred because they have sharp melting properties.

In the present invention, the polyester resin has an acid value of 2.0 to 30.0 mgKOH / g, preferably 2.0 to 25.0 mgKOH / g, more preferably 5.0 to 25.0 mgKOH / g. It is. In this case, excellent charging stability can be obtained in each environment.

The acid value of the polyester resin is 2.0 mg KO
If it is smaller than H / g, the toner tends to charge up and the image density tends to be low in a low-temperature and low-humidity environment. Further, the dispersibility of the compound (I) in the resin is reduced, the difference in the amount of charge between the toner particles is likely to occur, and fog tends to occur slightly with long-term durability.

The acid value of the polyester resin is 30.0 mgK
When it is larger than OH / g, the stability over time of the charging of the toner is reduced, and the charging amount is apt to be reduced together with the durability. Particularly in a high-temperature and high-humidity environment, image defects such as toner scattering and fogging are likely to occur.

Further, the acid value of the polyester resin is 30.
If it is higher than 0 mgKOH / g, it is difficult to block the adsorption of water even when compound (I) is blended in the toner.

In the present invention, in consideration of the storability and fixability of the yellow toner and the color mixing with other color toners, the glass transition temperature (Tg) of the polyester resin is 50 to 68 ° C., preferably 52 to 66 ° C. It is good to be ° C.

The glass transition temperature of the polyester resin is 50
When the temperature is lower than 0 ° C., although the fixing property is excellent, the offset resistance is reduced, and the fixing roller is contaminated and the winding around the fixing roller occurs, which is not preferable. Further, the gloss of the image surface after fixing becomes too high, and the image quality deteriorates, which is not preferable.

The glass transition temperature of the polyester resin is 68
If the temperature is higher than ° C., the fixability deteriorates, and the fixing temperature of the copying machine must be increased, and the resulting image generally has low gloss and low color mixing for a full-color toner.

The polyester resin used in the present invention comprises:
The number average molecular weight (Mn) is preferably from 1,500 to 50,
000, more preferably 2,000 to 20,000, and the weight average molecular weight (Mw) is preferably 6,000 to 10,
0000, more preferably 8,000 to 90,000
And Mw / Mn is preferably 2 to 8. A polyester resin that satisfies the above conditions has good heat fixability, improves the dispersibility of the colorant, reduces the variation in the charge amount of the yellow toner, and improves the reliability of image quality.

Number average molecular weight (Mn) of polyester resin
Is less than 1,500 or the weight-average molecular weight (Mw) is less than 6,000, the surface of the fixed image has high smoothness and vivid appearance, but offset occurs in durability. In addition, there is a concern about new problems such as a decrease in storage stability, a fusion of the toner in the developing device, and a generation of toner spent in which the toner component adheres to the carrier surface. Further, the shear is not easily applied during the melt-kneading of the raw materials in the production of the yellow color toner particles, the dispersibility of the yellow colorant is easily reduced, and therefore, the coloring power of the toner is reduced and the charge amount of the toner is easily changed.

Number average molecular weight (Mn) of polyester resin
Exceeds 50,000 or the weight average molecular weight (M
When w) exceeds 100,000, all have excellent offset resistance, but the fixing set temperature must be increased, and even if the degree of dispersion of the colorant can be controlled, the In this case, the surface smoothness at the portion is reduced, and the color reproducibility is easily reduced.

When the Mw / Mn of the polyester resin is less than 2, the generally obtained polyester resin has a small molecular weight itself. Therefore, similarly to the case where the molecular weight is small, an offset phenomenon due to durability and storage stability , Toner fusing in the developing device and toner spent on the carrier are liable to occur, and the charge amount of the toner tends to vary.

When the Mw / Mn of the polyester resin exceeds 8, although the offset resistance is excellent, the fixing temperature must be increased, and even if the degree of dispersion of the colorant can be controlled. In addition, the surface smoothness in the image portion is reduced, and the color reproducibility is easily reduced.

In the present invention, it is preferable to use the above-mentioned polyester resin alone, but it is preferable to use another resin such as an epoxy resin or a styrene-acrylic resin, or a polyester resin having different physical properties. You may mix and use. The resin to be mixed is not limited at all.

However, in the present invention, it is preferable that the above-mentioned polyester resin is contained in the total resin constituting the toner in an amount of 70% by weight or more, more preferably 80% by weight.
It is preferable to contain the above. If the amount is less than 70% by weight, the effects of stabilizing charging and stabilizing pigment dispersion, which are one of the objects of the present invention, cannot be obtained to the maximum.

In the present invention, the binder resin contains a polyester resin as a main component. The “main component” refers to a case where the content is 70% by weight or more based on the entire binder resin. Means

In the yellow toner of the present invention, if necessary, a fatty acid metal salt (eg, zinc stearate, aluminum stearate) and a fine powder of a fluorine-containing polymer (eg, polytetrafluoroethylene, polyvinylidene fluoride) may be used as a lubricant. And a fine powder of a tetrafluoroethylene-vinylidene fluoride copolymer), or a conductivity imparting agent such as tin oxide and zinc oxide.

Further, in the present invention, the yellow color toner may contain a release agent. For example, aliphatic hydrocarbon waxes, oxides of aliphatic hydrocarbon waxes, ester waxes, waxes mainly containing fatty acid esters, saturated linear fatty acids, unsaturated fatty acids, saturated alcohols, polyhydric alcohols , Fatty acid amides, saturated fatty acid bisamides, unsaturated fatty acid amides, and aromatic bisamides.

The content of the release agent in the yellow color toner is preferably 10 parts by weight or less, more preferably 8 parts by weight or less based on 100 parts by weight of the binder resin.

When the content of the release agent exceeds 10 parts by weight, blocking resistance and high-temperature offset resistance are liable to decrease, and transparency is also reduced.

These release agents are usually prepared by dissolving a binder resin in a solvent, increasing the temperature of the resin solution, and adding and mixing the release agent while stirring, or containing at least a binder resin and a colorant. The binder resin is preferably contained in the binder resin by a method of mixing a release agent at the time of kneading the toner constituent materials.

In the production of a yellow color toner, a toner kneading machine such as a hot roll, a kneader or an extruder is used to knead the toner constituent materials well, and then mechanically pulverized, and the pulverized powder is classified to obtain a toner; Alternatively, a method in which another toner constituent material such as a colorant is dispersed in a binder resin solution, followed by spray-drying, can be applied.

In the present invention, the weight average diameter (D ₄ ) of the yellow toner is 4.0-15.0 μm, preferably 5.0-12.0 μm, more preferably 6.0-10.
0 μm is good.

When the weight average diameter (D ₄ ) of the yellow toner is less than 4.0 μm, it is difficult to stabilize the charge, and fog and toner scattering are liable to occur in durability.

The yellow toner has a weight average diameter (D ₄ ) of 1
If it exceeds 5.0 μm, the reproducibility of the halftone portion is greatly reduced, and the obtained image becomes a rough image.

In the yellow toner of the present invention, a hydrophobicized titanium oxide fine powder or aluminum oxide fine powder having an average primary particle diameter of 0.002 to 0.2 μm is added to the yellow color toner particles as a fluidity improver. It is good to be attached.

The fluidity improver as an external additive is an important factor not only for increasing the fluidity of the yellow toner but also for further improving the chargeability of the yellow toner.

Therefore, it is desirable that the surface of the titanium oxide fine powder or the aluminum oxide fine powder is subjected to a hydrophobic treatment, so that it is possible to simultaneously impart fluidity and stabilize charging.

Since the titanium oxide fine powder or the aluminum oxide fine powder has been subjected to a hydrophobic treatment, the influence of water, which is a factor affecting the charge amount, is excluded, and the difference in the charge amount between high and low humidity conditions. , The environmental characteristics of the yellow toner can be further improved. In particular, it is effective in increasing the charge amount in a high-temperature and high-humidity environment and preventing a decrease in the charge amount after standing. Furthermore, it becomes possible to prevent the primary particles from aggregating during the hydrophobic treatment step, and the external additive with less secondary agglomeration can provide more uniform charging to the yellow toner.

In the present invention, in particular, titanium oxide fine powder or alumina fine powder having an average primary particle diameter of 0.002 to 0.2 μm has good fluidity, and the negatively charged yellow toner is uniformly charged. It is preferable because scattering and fogging hardly occur. Further, the toner is hardly embedded in the surface of the yellow color toner particles, so that the toner is hardly deteriorated, and the durability of a large number of sheets is improved. This tendency is more remarkable in the color toner having the sharp melt property.

When the average primary particle diameter of the titanium oxide fine powder or the aluminum oxide fine powder is less than 0.002 μm, the fine powder is easily embedded in the surface of the yellow color toner particles, the toner is easily deteriorated, and the durability is improved. Easily deteriorates. This tendency is more remarkable when applied to a color toner having a sharp melt property.

If the thickness exceeds 0.2 μm, the fluidity is reduced and the charging of the yellow toner is likely to be non-uniform. As a result, the toner is liable to be scattered and fogged.
It becomes difficult to generate a high quality toner image.

In the yellow toner of the present invention, the amount of the fine titanium oxide powder or the fine aluminum oxide powder is preferably 0.2 to 5.0% by weight, more preferably 0.3 to 5.0% by weight.
-3.0% by weight, more preferably 0.5-2.5% by weight. The yellow toner that satisfies the above range has good fluidity, can maintain a stable charge amount, and hardly causes toner scattering.

In the yellow toner, the addition amount of the titanium oxide fine powder or the aluminum oxide fine powder was 0.2% by weight.
If the value is less than 1, the fluidity of the toner is insufficient.
Mixability with the carrier decreases, fog during durability,
Toner scattering is likely to occur.

If the content exceeds 5.0% by weight, the fine powder detached from the surface of the toner particles causes filming on the surface of the photosensitive drum or cleaning failure easily occurs. Fog is also likely to occur.

The yellow toner of the present invention can be used as a two-component developer by being mixed with magnetic carrier particles as a carrier, but can also be used as a one-component developer without being mixed with a carrier. is there.

When the yellow toner of the present invention is used in a two-component developer, the carrier used may be, for example, a metal such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, etc. And their magnetic alloys or oxides and ferrites.

When the carrier is a coated carrier obtained by coating a carrier core with a coating material, a method for coating the surface of the carrier core with the coating material is to dissolve or suspend the coating material in a solvent, apply the coating material, and adhere to the carrier core. How to make
A method of simply mixing in a powder state can be applied.

Examples of the coating material for the carrier core include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, styrene resin, acrylic resin, polyamide, polyvinyl butyral, and aminoacrylate resin. No. These are suitably used alone or in combination.

The processing amount of the above materials may be determined as appropriate, but generally, the total amount is 0.1 to 30% by weight based on the carrier.
(Preferably 0.5 to 20% by weight).

The carrier used in the present invention has an average particle size of preferably 10 to 100 μm, more preferably 20 to 100 μm.
The thickness is preferably 70 μm.

If the average particle size of the carrier is less than 10 μm, the packing of the two-component developer is strengthened, the mixing property between the toner and the carrier is reduced, and the chargeability of the toner is hardly stabilized. Adhesion to the surface of the photosensitive drum is likely to occur.

When the average particle size of the carrier exceeds 100 μm, the chance of contact with the toner is reduced, so that the toner having a low charge amount is mixed and fog is easily generated. Further, since the toner tends to be scattered, the setting of the toner concentration in the two-component developer needs to be set low, and an image with high image density may not be formed.

As a particularly preferred carrier, the surface of a magnetic core particle such as a magnetic ferrite core particle is coated with a resin such as a silicone resin, a fluorine resin, a styrene resin, an acrylic resin and a methacrylate resin, preferably from 0.01 to 0.01%. 5% by weight, more preferably 0.1 to 1% by weight
And a magnetic-coated carrier having an average particle size of 30 to 60 μm.

When the magnetic coated carrier has a sharp particle size distribution, a favorable triboelectrification property is obtained with respect to the yellow toner of the present invention, and the effect of improving electrophotographic properties is obtained.

When a two-component developer is prepared by mixing a yellow toner and a carrier, the mixing ratio is 2 to 15% by weight, preferably 3 to 13% by weight, as the toner concentration in the developer. %, More preferably 4% by weight to 1%
Good results are usually obtained at 0% by weight. If the toner density is less than 2% by weight, the image density tends to be low.
If the content is more than 1% by weight, fogging and scattering in the machine tend to occur, and the useful life of the developer tends to be shortened.

Next, the yellow toner of the present invention is applied,
Figure 1 shows a method for forming a full-color image by electrophotography.
This will be described with reference to FIG.

FIG. 1 is a schematic diagram showing an example of an image forming apparatus for forming a full-color image by electrophotography. 1 is used as a full-color copying machine or a full-color printer. In the case of a full-color copying machine, as shown in FIG. 1, a digital color image reader unit is provided at the upper part, and a digital color image printer unit is provided at the lower part.

In the image reader section, the original 30 is placed on the original platen glass 31 and is exposed and scanned by the exposure lamp 32, so that the reflected light image from the original 30 is condensed on the full color sensor 34 by the lens 33, and the color image is reflected. Obtain a decomposed image signal. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to a digital image printer unit.

In the image printer section, the photosensitive drum 1, which is an image carrier, has a photosensitive layer having, for example, an organic photoconductor, and is carried rotatably in the direction of the arrow. Around the photosensitive drum 1, a pre-exposure lamp 11, a corona charger 2, a laser exposure optical system 3, a potential sensor 12, four developing machines 4Y, 4C, 4M, 4B of different colors, and a light amount detecting means 13 on the drum , A transfer device 5 and a cleaning device 6 are arranged.

In the laser exposure optical system, an image signal from the reader section is converted into an optical signal for image scan exposure by a laser output section (not shown), and the converted laser light is reflected by the polygon mirror 3a. The light is projected onto the surface of the photosensitive drum 1 via the lens 3b and the mirror 3c.

At the time of image formation, the printer unit
Is rotated in the direction of the arrow, and after the charge is removed by the pre-exposure lamp 11, the photosensitive drum 1 is uniformly negatively charged by the charger 2 to irradiate a light image E for each of the separated colors, and the electrostatic charge is charged on the photosensitive drum 1. Form an image.

Next, a predetermined developing device is operated to develop the electrostatic charge image on the photosensitive drum 1 to form a toner image on the photosensitive drum 1 with toner. Developing units 4Y, 4C, 4M,
4B are eccentric cams 24Y, 24C, 24M,
By the operation of 24B, development is performed by selectively approaching the photosensitive drum 1 in accordance with each separation color.

The transfer device includes a transfer drum 5a, a transfer charger 5b, an attraction charger 5c for electrostatically attracting a recording material and an attraction roller 5g opposed thereto, and an inner charger 5c.
d, an outer charger 5e and a decomposition charger 5h. The transfer drum 5a is rotatably supported so as to be rotatable, and a transfer sheet 5f, which is a transfer material carrier that supports a transfer material in an opening area of a peripheral surface thereof, is integrally adjusted on a cylinder. A resin film such as a polycarbonate film is used for the transfer sheet 5f.

The transfer material is transported from the cassette 7a, 7b or 7c to the transfer drum 5a through a transfer sheet transport system, and is carried on the transfer drum 5a. The transfer material carried on the transfer drum 5a is repeatedly conveyed to the transfer position facing the photosensitive drum 1 with the rotation of the transfer drum 5a, and is transferred onto the transfer material by the action of the transfer charger 5b while passing through the transfer position. The toner image on the photosensitive drum is transferred.

As shown in FIG. 1, the toner image may be directly transferred from the photoconductor to a transfer material, or the toner image on the photoconductor may be transferred to an intermediate transfer member, and the toner image may be transferred from the intermediate transfer member. It may be transferred to a material.

The above-described image forming step is performed by using yellow (Y),
By repeating the process for magenta (M), cyan (C), and black (B), a color image in which four color toner images are superimposed on the transfer material on the transfer drum 5 is obtained.

The transfer material on which the toner images of the four colors have been transferred in this manner is separated from the transfer drum 5a by the action of the separation claw 8a, the separation push-up roller 8b and the separation charger 5h. 9, where the toner is heated and pressurized and fixed, so that the toner is mixed, colored and fixed on the transfer material, and is fixed to a full-color image. Then, the image is discharged to the tray 10 and the formation of the full-color image is completed. I do. On the other hand, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned and removed by the cleaning device 6. As the cleaning member, besides the blade, a fur brush or a nonwoven fabric, or a combination thereof may be used.

For the transfer drum 5a, the transfer sheet 5
electrode roller 14 and fur brush 1 facing each other
5, an oil removing roller 16 and a backup brush 17 are provided, and the transfer sheet 5 of the transfer drum 5a is provided.
Cleaning is performed in order to remove the adhered powder on f and the adhered oil on the transfer sheet 5f. Such cleaning is performed before or after image formation, and at any time when a jam, that is, a paper jam occurs.

The gap between the transfer sheet 5f and the photosensitive drum 1 can be arbitrarily set by operating the eccentric cam 25 at a desired timing and operating the 29 cam follower 5i integrated with the transfer drum 5a. And For example, the interval between the transfer drum 5a and the photosensitive drum 1 can be increased during standby or when the power is off.

A full-color image is formed by the image forming apparatus. In the image forming apparatus, a single-color fixed image or a multi-color fixed image can be formed in the single-color mode or the multi-color mode.

Next, the method of measuring each physical property will be described below.

Measurement of Particle Size Distribution of Toner A Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter) is used. The electrolyte is about 1% using primary grade sodium chloride.
Adjust the aqueous NaCl solution. For example, ISOTON R
-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, a surfactant (preferably an alkylbenzene sulfonate) is used as a dispersant in 100 to 150 ml of the aqueous electrolytic solution in an amount of 0.1 to 5 m.
and 2 to 20 mg of the measurement sample. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and 10
Using a 0 μm aperture, the volume and number of toner particles are measured for each channel to calculate the volume distribution and the number distribution of the toner. Then, the weight average diameter (D ₄ ) of the toner based on the weight obtained from the volume distribution of the toner particles (the median value of each channel is set as a representative value for each channel) is obtained.

The channels are 2.00 to 2.52
μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm
m; 4.00 to 5.04 μm; 5.04 to 6.35 μm
m; 6.35 to 8.00 μm; 8.00 to 10.08 μm
m; 10.08 μm to 12.70 μm; 12.70 to 1
6.00 μm; 16.00-20.20 μm; 20.2
0 to 25.40 μm; 25.40 to 32.00 μm; 3
13 channels of 2.00 to 40.30 μm are used.

Measurement of glass transition temperature of polyester resin
Method In the present invention, the measurement is performed using a differential thermal analysis measurement device (DSC measurement device), DSC-7 (manufactured by PerkinElmer).

The measurement sample is 5 to 20 mg, preferably 10
Weigh the mg precisely.

This was put in an aluminum pan, and an empty aluminum pan was used as a reference.
The measurement is performed at a temperature rising rate of 10 ° C./min under normal temperature and normal humidity between 00 ° C.

In this heating process, an endothermic peak of a main peak in a temperature range of 40 to 100 ° C. is obtained.

At this time, the intersection between the line of the midpoint of the baseline before and after the endothermic peak appears and the differential heat curve is defined as
In the present invention, the glass transition temperature is defined as Tg.

Method for Measuring Molecular Weight of Polyester Resin Mn, Mw and Mw / Mn of the polyester resin are measured by gel permeation chromatography (GPC). The column is stabilized in a heat chamber at 40 ° C., and the column at this temperature is made to flow at a flow rate of 1 ml per minute with tetrahydrofuran (THF) as a solvent.
Measure by injecting about 100 μl of HF sample container. When measuring the molecular weight of a sample, the molecular weight distribution of the sample
It is calculated from the relationship between the logarithmic value of the calibration curve prepared from several kinds of monodisperse polystyrene standard samples and the count number. As the standard polystyrene samples for preparing the calibration curve, for example, manufactured by Tosoh Corporation or molecular weight of Showa Denko KK 10 ^2-1
Used of about 0 ^7, it is appropriate to use at least about 10 standard polystyrene samples. The detector has R
A 1 (refractive index) detector is used. As the column, a combination of a plurality of commercially available polystyrene gel columns is preferably used.

For example, Shodex G manufactured by Showa Denko KK
PC KF-801,802,803,804,80
5,806,807,800P, TSKgel G1000H (H _XL ), G2000
H (H _XL ), G3000H (H _XL ), G4000H (H
_{XL), G5000H (H XL)} , G6000H (H XL),
G7000H (H _XL ), TSKguardcolumn
Can be cited.

A sample is prepared as follows.

The sample is placed in THF, left for several hours, shaken sufficiently, mixed well with THF (until the sample is no longer united), and allowed to stand for 12 hours or more. Then T
The time of leaving in HF is set to 24 hours or more.
After that, the sample processing filter (pore size 0.45
０．５0.5 μm, for example, Myshodisk H-25-
5 The product passed through Tosoh Co., Ltd., Exirodisc 25CR, Germanic Science Japan, etc.) can be used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

Measurement Method of Oxidation A 2 to 10 g sample was weighed in a 200 to 300 ml Erlenmeyer flask, and about 50 ml of a mixed solvent of methanol: toluene = 30: 70 was added to dissolve the resin. If solubility is poor, a small amount of acetone may be added. 0.1%
Using a mixed indicator of bromthymol blue and phenol red, titration is performed with a pre-specified N / 10 caustic potassium-alcohol solution, and the acid value is determined from the consumption of the alcoholic potassium solution by the following calculation. Acid value = KOH (number of ml) × N × 56.1 / weight of sample (where N is a factor of N / 10 KOH) Measuring method of triboelectric charge amount of toner And the case of a one-component developer are described below.

(Two-Component Developer) FIG. 2 is an explanatory view of an apparatus for measuring the triboelectric charge amount. About 0.5 to 1.5 g of a two-component developer collected from a developing sleeve of a copying machine or a printer is put in a metal measuring container 52 having a 500-mesh screen 53 at the bottom, and a metal lid 54 is placed. .
At this time, the weight of the entire measurement container 52 is weighed and defined as W ₁ (g). Next, in the suction device 51 (at least a portion in contact with the measurement container 52 is an insulator), the pressure of the vacuum gauge 55 is adjusted to 250 mmAq by adjusting the air volume control valve 56 by suctioning from the suction port 57.
And In this state, suction is sufficiently performed, preferably for 2 minutes, to remove the toner by suction. The potential of the electrometer 59 at this time is V
(Volts). Here, 58 is a capacitor whose capacity is C (mF). Further, the weight of the whole measurement container after suction is weighed to be W ₂ (g). The triboelectric charge (mC / kg) of this sample is calculated as shown below.

Amount of triboelectric charge of sample (mC / kg) = C × V
/ (W ₁ -W ₂ )

(One-Component Developer) The triboelectric charge of the one-component developer is determined by a suction Faraday cage method.

The suction type Faraday cage method is to collect and collect all the one-component developer in a fixed area on a developing sleeve of a copying machine or a printer by using a developer collecting device.
In this method, the weight and charge amount of the collected developer are measured, and the charge amount per unit weight of the developer, that is, the triboelectric charge amount (mC / kg) is determined from the measured weight and charge amount of the developer. .

The developer collecting device used in the suction type Faraday cage method has a suction device for sucking air and a collecting device for collecting the developer connected to the suction device. . An outer cylinder having a suction port having a tip portion having a curvature corresponding to the outer peripheral curvature of the developing sleeve for sucking the developer on the developing sleeve,
And a cylinder having a cylindrical filter paper for collecting the sucked developer.

In order to specifically perform the suction and recovery of the developer on the developing sleeve using the developer collecting device, the rotation of the developing sleeve is stopped, and the developer collecting device is used to collect the developer on the developing sleeve. The developer is sucked from one end to the other end of the developing sleeve along the longitudinal direction while pressing the suction port of the developer collecting device against the surface of the developing sleeve, and the sucked developer is collected by a cylindrical filter paper.

The weight of the cylindrical filter paper from which the developer was recovered was measured, and
The value obtained by subtracting the weight of the cylindrical filter paper before recovery from the weight of the cylindrical filter paper after recovery is defined as the weight of the recovered developer. At this time, the charge amount of the developer collected on the cylindrical filter paper which is electrostatically shielded from the outside is measured in advance.

The flatness of titanium oxide fine particles and alumina fine particles
Measurement method of uniform particle diameter The primary particle diameter of titanium oxide fine particles and alumina fine particles on toner particles was determined by observing with a scanning electron microscope and expanding 300,000 to 50,000 times in the visual field 300 titanium oxide fine particles and alumina fine particles. The average particle size is determined by qualifying with an XMA (X-ray microanalyzer) and measuring the particle size.

Method for measuring the average particle size of the carrier The carrier was measured using a Microtrac particle size analyzer SRA type (manufactured by Nikkiso Co., Ltd.) in a range of 0.7 to 700 μm, and 50% of the measured carrier was measured.
In the present invention, the particle size is defined as the average particle size of the carrier.

The primary and secondary diameters of the primary particles of the yellow colorant
Measurement of Ratio The major and minor diameters of the primary particles of the yellow pigment particles constituting the yellow colorant were obtained by observing the yellow pigment particles themselves with a scanning electron microscope and magnifying them by 30,000 to 50,000 times in the visual field. The major axis and minor axis of 300 pigment particles of 1 μm or more are measured, and the ratio of the average value is taken as the ratio of major axis to minor axis.

The value of the ratio of the major axis to the minor axis of the primary particles of the yellow colorant can be measured also from the yellow colorant in the yellow toner particles described later, and there is no substantial difference in the measured values.

The yellow colorant in the yellow toner particles
Measurement of number average diameter Add yellow toner or yellow toner particles to a 2.3M sucrose solution, stir well, apply a small amount of this to a sample holder pin, then put into liquid N ₂ to solidify, and immediately apply it to the sample arm head. set.

A sample is prepared by cutting with an ultramicrotome FC4E equipped with a cryo device (manufactured by Nissan Sangyo) in accordance with a conventional method.

A photograph was taken at an acceleration voltage of 100 kV using an electron microscope H-8000 (manufactured by Hitachi, Ltd.). The magnification is 30,000-50,000 times.

The image information is introduced into an image analysis device (Luzex3) manufactured by Nicole via an interface, and
Convert to value image data. Among them, only the pigment particles having a primary particle diameter and a secondary particle diameter of 0.1 μm or more are randomly analyzed, and the number of sampling is 300
The measurement is repeated until the number exceeds the number of times, and the number average diameter of the pigment particles is determined.

The number average diameter in the present invention is an average value of the major diameters of the primary particles and the secondary particles of the yellow pigment particles.

The ratio of the major axis to the minor axis of the primary particle size of the yellow colorant can be determined by a similar method by measuring pigment particles having a primary particle size of 0.1 μm or more.

[0158]

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 Polyester Resin No. 170 parts by weight [polyoxypropylene (2.2) -2,2-bis (4
-Hydroxyphenyl) Polyester resin produced from propane terephthalic acid fumaric acid trimellitic acid (acid value 10.3mgK
OH / g, Tg = 56 ° C., Mn = 3900, Mw = 12
700, Tm = 90 ° C.) 30 parts by weight of a yellow pigment represented by the following structural formula (ratio of major axis to minor axis of primary particles = 1.8)

[0160]

[Outside 6]

The above materials were charged into a kneader type mixer,
While mixing, the temperature is raised under non-pressure, and the mixture is sufficiently premixed.
Thereafter, the mixture was kneaded twice with three rolls to obtain a first kneaded material. -The above kneaded material (pigment content is 30% by weight) 16.7
Part by weight ・ Polyester resin No. 188.3 parts by weight-Zirconium compound of di-tert-butylsalicylic acid represented by the following structural formula: 4 parts by weight

[0162]

[Outside 7]

The above materials were sufficiently premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, roughly crushed by a hammer mill to about 1-2 mm, and then finely crushed by an air jet method. Finely ground. Further, the obtained finely pulverized product was strictly removed at the same time by a multi-division classifier to obtain yellow color toner particles having a weight average diameter of 8.0 μm. The number average diameter of the colorant in the toner was 0.20 μm.

On the other hand, as external additives (fluidity improver and charge stabilizer), hydrophilic titanium oxide fine powder A (primary average particle diameter 0.02 μm, BET specific surface area 140 m ² / g) 1
N-C ₄ H ₉ -Si against 00 parts by weight (OCH _{3) 3}
Was used to obtain a hydrophobic fine titanium oxide powder B having a primary average particle diameter of 0.02 μm and a degree of hydrophobicity of 70%.

100 parts by weight of yellow color toner particles and 1.0 part by weight of hydrophobic titanium oxide fine powder B were mixed to prepare Yellow Toner 1 having hydrophobic titanium oxide fine particles on the surface of yellow color toner particles.

The magnetic ferrite carrier particles (average particle size: 5
0 μm) to obtain a two-component yellow developer.

The above-mentioned two-component yellow developer was used in a commercially available plain paper full-color copying machine (color laser copying machine CLC70).
0, manufactured by Canon Inc.), and a copy test was performed. The image density was as high as 1.7 to 1.8 even in a durability test of 50,000 sheets under a normal temperature and normal humidity environment (23 ° C., 60%). Shows the density and the initial fluctuation is small in the charging characteristics.
/ Kg to -26 mC / kg.

After the endurance of 50,000 sheets, no filming due to fusion of the toner was observed on the surface of the photosensitive drum, and no cleaning failure occurred during this time.

No offset to the fixing roller occurred at all in the 50,000-sheet durability copy. The surface of the fixing roller after the endurance was visually observed, and there was no contamination by the toner.

When the surface of the carrier in the developer after 50,000 sheets of durability was observed by SEM, almost no toner spent was observed.

Further, in a high temperature and high humidity environment (30 ° C., 80%)
A durability test was performed on 50,000 sheets under a low-temperature and low-humidity environment (15 ° C., 10%), but no fog or scattering occurred, and the image density remained almost stable.

Table 9 shows the evaluation results of the durability test in a high-temperature, high-humidity environment and a low-temperature, low-humidity environment.

Next, instead of the yellow pigment, C.I. I.
Pigment Blue 15: 3 in an amount of 8.0 μm in substantially the same manner except that 4 parts by weight of Pigment Blue 15: 3 was used.
m cyan color toner particles were obtained.

Further, in place of the yellow pigment, C.I.
I. Pigment Red 122 is used in the same manner except that 5 parts by weight of Pigment Red 122 is used.
m magenta color toner particles were obtained.

To the obtained cyan color toner particles and magenta color toner particles, in the same manner as the yellow toner, 1.0 part by weight of hydrophobic titanium oxide fine powder B was mixed, and the hydrophobic titanium oxide fine particles B Was obtained, and a two-component cyan developer and a two-component magenta developer were prepared in the same manner thereafter.

The amount of toner on the unfixed transfer material is 0.8% for the yellow toner, magenta toner and cyan toner.
The contrast potential of the main body was adjusted so as to be mg / cm ² , and a green solid image was output with the yellow toner and the cyan toner, and a red solid image was output with the yellow toner and the magenta toner.

As a method of evaluating a color copied image, there is a method of determining the quality of a color image by measuring the gloss (gloss) of the image surface and the chromaticity of the image. The higher the gross value, the smoother the surface of the image and the more lustrous saturation (C ^* )
Color quality is high, and if the gloss value is low,
It is determined that the image surface with poor dull saturation (C ^* ) is rough. Note that “C ^* ” is calculated from the values of a ^* and b ^* measured by the following method using the following formula.

[0178]

[Outside 8] The larger the C ^* , the brighter the image.

For measurement of gloss (gloss), a VG-10 type gloss meter manufactured by Nippon Denshoku Co., Ltd. was used. When measuring,
First, the voltage was set to 6 V by a constant voltage device, and then the light emitting angle and the light receiving angle were adjusted to 60 °, respectively, using a zero point adjustment and a standard plate. Overlap three white papers and measure.
The numerical value shown on the display was read in%.

The color tone of the toner was quantitatively measured based on the definition of the color system standardized by the International Commission on Illumination (CIE) in 1976. That is, a ^* and b ^* (a ^* and b ^* are chromaticities indicating hue and saturation) and L ^* (brightness) were measured. A spectrophotometer type 938 manufactured by X-Rite was used as the measuring instrument, the light source for observation was C light source, and the viewing angle was 2 °.

The gloss and chromaticity of each image in Example 1 are as shown in Table 1 below.

[0182]

[Table 1]

When the yellow toner of the present invention was used, the images of green and red, which are the secondary colors, were also high in brightness and saturation.

Further, the transparency film on which a color image was formed using the transparency film as a transfer material was transferred to an overhead projector (OH
The transparency of the OHP image projected on P) was also good.

The transparency of the OHP image in the above embodiment was evaluated based on the following evaluation criteria by projecting a color image formed with the above-mentioned yellow toner on a transparency film using a commercially available overhead projector. did.

A: Excellent in transparency, no unevenness in light and dark, and excellent in color reproducibility. (Good) B: Although there is slight unevenness in brightness, there is no practical problem.
(Possible) C: Light and dark unevenness and poor color reproducibility. (bad)

When the light fastness of the obtained solid yellow image (image density 1.70) was confirmed substantially in accordance with JIS K7102, the image density after light irradiation for 200 hours was almost the same as the initial image density (1.70). 67), and the hue change was also slight (ΔE = 2.8).

An ultraviolet carbon arc lamp was used as a light source.

The change in hue was determined by calculating the ΔE value of the following formula, and was quantitatively evaluated based on the following evaluation standard of light fastness.

ΔE = ｛(L ₁ ^* −L ₂ ^* ) ² + (a ₁ ^*
−a ₂ ^* ) ² + (b ₁ ^* −b ₂ ^* ) ² ｝ ^1/2 L ₁ ^* : brightness of image before light irradiation a ₁ ^* , b ₁ ^* : hue and saturation of image before light irradiation L ₂ ^* : lightness of image after light irradiation a ₂ ^* , b ₂ ^* : chromaticity indicating hue and saturation of image after light irradiation

Evaluation standard of light resistance A: No fading even after irradiation for 200 hours. B: Does not fade even after irradiation for 100 hours. C: Discolored after irradiation for 100 hours.

Comparative Example 1 The polyester resin No. used in Example 1 Polyester resin No. 1 2 [Polyoxypropylene (2.2) -2,2-bis (4
-Hydroxyphenyl) Condensed polymer consisting of propane terephthalic acid fumaric acid trimellitic acid (acid value 1.9 mgKOH / g, T
g = 59 ° C., Mn = 4100, Mw = 12000, Tm
= 93 ° C)], except that yellow toner 2 (weight average diameter: 8.0 µm) was obtained in the same manner as in Example 1. Evaluation was performed in the same manner as in Example 1. As a result, the image density began to decrease from around the 10,000th sheet due to durability in a low-temperature and low-humidity environment, and the image became rough and fogging started when durability was further continued. When the initial OHP image was compared with the yellow toner 1, the transparency was reduced.

Comparative Example 2 Polyester resin No. 1 used in Example 1 Polyester resin No. 1 3 [Polyoxypropylene (2.2) -2,2-bis (4
-Hydroxyphenyl) Condensed polymer consisting of propane terephthalic acid fumaric acid trimellitic acid (acid value 31.2 mgKOH / g,
Tg = 55 ° C., Mn = 4800, Mw = 11000, T
m = 93 ° C.)], except that yellow toner 3 (weight average diameter: 7.8 μm) was obtained in the same manner as in Example 1. Evaluation was made in the same manner as in Example 1. As a result, the charge amount was low under a high-temperature and high-humidity environment, and toner scattering began to be noticeable as well as durability.

Example 2 The polyester resin No. used in Example 1 was used. Instead of 1,
Polyester resin No. 4 (condensed polymer of propoxylated bisphenol A and fumaric acid, acid value: 4.0 mg
KOH / g, Tg: 60 ° C., Mw: 15000, Mn:
4200, Mw / Mn: 3.57), except that yellow toner 4 (weight average diameter: 8.2 μm) was obtained in the same manner as in Example 1. When the evaluation was performed in the same manner as in Example 1 using the yellow toner 4, the image density began to decrease from around the 20,000th sheet due to durability in a low-temperature and low-humidity environment, but was within a practical level.

Example 3 The polyester resin No. used in Example 1 Instead of 1,
Polyester resin No. 5 (condensation polymer of propoxylated bisphenol A and fumaric acid, acid value: 25.8 m)
gKOH / g, Tg: 55 ° C., Mw: 11,000, M
n: 3800, Mw / Mn: 2.89), except that yellow toner 5 was used in the same manner as in Example 1.
(Weight average diameter: 7.9 μm). When the evaluation was performed in the same manner as in Example 1 using the yellow toner 5, the charge amount was slightly reduced in a high-temperature and high-humidity environment, but no problem occurred on the image.

Comparative Example 3 The polyester resin No. used in Example 1 Instead of styrene / acrylic resin No. 1 6 [styrene-n-butyl acrylate copolymer (acid value 0 mgKOH / g, Tg = 60 ° C., Mn = 5200,
Mw = 22000, Tm = 96 ° C.), except that the yellow toner 6 (weight average diameter: 8.1 μm) was obtained. When the gloss and chromaticity of the image of the yellow toner 6 were examined in the same manner as in Example 1, the results shown in Table 2 were obtained.

[0197]

[Table 2] As shown in Table 2, both the lightness and the saturation of the yellow toner 6 decreased.

When the yellow toner 6 was used in a low-temperature and low-humidity environment, the charge amount increased and the image density became low.

Comparative Example 4 In place of the coloring agent used in Example 1, the following formula (III)

[0200]

[Outside 9] (III) (CI Pigment)
A yellow toner 7 was prepared in the same manner as in Example 1 except that Yellow 12) was used, and evaluated in the same manner as in Example 1. Although the durability changed relatively stably under each environment, the obtained yellow image was faded by a light fast acceleration test of carbon arc lamp irradiation (10).
ΔE = 12 with light irradiation for 0 hours). Compound (III)
The ratio of the major axis to the minor axis of the primary particles was 2.4.

[0201]

[Table 3]

Example 4 In place of the hydrophobic titanium oxide fine powder B used in Example 1,
Hydrophilic aluminum oxide fine powder C (Primary average particle size:
0.02 μm, BET specific surface area: 130 m ² / g) 10
Iso-C ₄ H ₉ -Si respect 0 parts by weight (OCH _3)
3 using 17 parts by weight of a surface treatment and a primary particle diameter of 0.0
A 2 μm hydrophobic aluminum oxide fine powder D having a hydrophobicity of 70% was obtained. A yellow toner 8 was prepared in the same manner as in Example 1 except that the hydrophobic aluminum oxide fine powder D was used, and evaluated in the same manner as in Example 1.

In each environment, good durability was exhibited, and light resistance and hue showed almost the same tendency as in Example 1.

Example 5 Instead of the hydrophobic titanium oxide fine powder B used in Example 1,
Hydrophilic titanium oxide fine powder A (primary average particle size: 0.02
μm, BET specific surface area: 140 m ² / g) was used as it was without surface treatment, and thereafter yellow toner 9 was prepared and evaluated in the same manner as in Example 1.

In a high-temperature, high-humidity environment, the initial charge amount was as low as −15 mC / kg, which was almost the level of durability evaluation. Furthermore, when the durability was advanced under the same environment, the image became rough with a halftone portion, but it was within a practical level. However, the charge amount one day after the image was left standing was reduced by about 3 mC / kg as compared to that before the image was left standing. In addition, toner scattering and fogging were observed as well as durability.

Example 6 Instead of the hydrophobic titanium oxide fine powder B used in Example 1,
Hydrophilic silica E (primary average particle diameter: 0.005 μm,
(BET specific surface area: 380 m ² / g) Hydrophobic silica F having a primary particle diameter of 0.005 μm and a hydrophobicity of 65%, which was surface-treated using 20 parts by weight of hexamethyldisilazane per 100 parts by weight. A yellow toner 10 was obtained in the same manner as in Example 1 except for the above. Yellow toner 10
And evaluated in the same manner as in Example 1. In the durability under a low-temperature and low-humidity environment, the charge amount of the toner started to increase and the image density began to decrease around the 2,000th sheet, and the image became rough, but it was still within a practical level.

However, when the surface of the carrier after the endurance was observed, toner spent was found, but this was also within a practical level. In durability under a high temperature and high humidity environment, fog and toner scattering tended to be deteriorated as well as durability.

Comparative Example 5 In place of compound (I) used in Example 1, the following formula (I)
V)

[0209]

[Outside 10] (IV) (CI Pigment)
Yellow 74 was obtained in the same manner as in Example 1 except that 7 parts by weight of Yellow 74) was used per 100 parts by weight of the polyester resin, and was evaluated in the same manner as in Example 1. From about 5,000 sheets of endurance of many sheets under the environment, the charge amount of the toner starts to decrease,
In addition, endurance was suspended because fog started to stand out.
The ratio of the major axis to the minor axis of the primary particles of the compound (IV) is 2.
Nine.

Further, the compound (IV) has a lower coloring power than the compound (I) used in Example 1, and in order to obtain an image having a high image density, the contrast potential of a full-color copying machine must be adjusted. It had to be higher than in Example 1.

Comparative Example 6 In place of compound (I) used in Example 1, the following formula (V)

[0212]

[Outside 11] (V) (CI Pigment Y)
Yellow 95) was obtained in the same manner as in Example 1 except for using the yellow 95), and the evaluation was performed in the same manner as in Example 1. As a result, the initial image had a high image density (1.60). Although it was within the practical level, the image density gradually decreased during many-sheet running. That is, the image density after 10,000 sheets of durability was reduced to 1.20. In addition, the ratio of the major axis to the minor axis of the primary particles of the compound (V) was 3.4.

Example 7 A yellow toner was prepared in the same manner as in Example 1, except that 4 parts by weight of an aluminum compound of di-tert-butylsalicylic acid was used instead of the zirconium compound of di-tert-butylsalicylic acid. 13
I got When evaluation was performed in the same manner as in Example 1 using the yellow toner 13, good results were obtained.

Example 8 A yellow toner 14 was obtained in the same manner as in Example 1, except that a zinc compound of di-tert-butylsalicylic acid was used in place of the zirconium compound of di-tert-butylsalicylic acid. . When the evaluation was performed in the same manner as in Example 1 using the yellow toner 14, the image density decreased due to charge-up from around the 10000th sheet due to durability in a low-temperature and low-humidity environment. In the durability, the charge amount was reduced from about the 5000th sheet, and although toner scattering and fogging were slightly observed, both were within the practical level.

When the gloss and chromaticity of the image of the yellow toner 14 were examined in the same manner as in Example 1, the results shown in Table 4 were obtained.

[0216]

[Table 4]

Compared with the toner of Example 1, the yellow toner 14 has lower brightness and saturation in spite of the substantially higher gloss of the image, which is caused by the poor colorant. it is conceivable that.

Although the transparency of an actual OHP image was not very good, it was within a practical level.

Example 9 In Example 1, hydrophilic titanium oxide G having a primary particle diameter of 0.22 μm was used instead of hydrophobic titanium oxide fine powder B.
(BET specific surface area: 20 m ² / g) 100 parts by weight of n-C ₄ H ₉ —Si (OCH ₃ ) ₃ with 10 parts by weight of surface treated, primary particle diameter 0.22 μm, degree of hydrophobicity Toner 15 was prepared in the same manner except that 68% of hydrophobic titanium oxide fine powder H was used, and the durability was evaluated.

Although the uniformity of the halftone portion was inferior from the initial stage of the durability and the uniformity of the solid image was inferior to that of Example 1, it was within a practical level.

In the endurance under low temperature and low humidity, the image density began to decrease with the endurance. Also, the transparency of the OHP was at a level having no practical problem, although slight unevenness was observed from the beginning.

Example 10 In substantially the same manner as in Example 1, yellow toner particles having a weight average diameter of 10.5 μm were obtained. As an external additive, 0.8 parts by weight of hydrophobic titanium oxide fine powder B was mixed with 100 parts by weight of yellow toner particles to prepare a yellow toner 16.

In terms of durability, although almost satisfactory results were obtained, the halftone uniformity and line reproducibility were slightly inferior to those in Example 1. However, it was within the practical level.

Example 11 In substantially the same manner as in Example 1, yellow toner particles having a weight average diameter of 5.3 μm were obtained. Yellow toner 17 was prepared by mixing 15 parts by weight of hydrophobic titanium oxide fine powder B as an external additive with 100 parts by weight of yellow toner particles.

Although the highlight reproducibility was at a level higher than that of Example 1, the image density was slightly lower in durability under low temperature and low humidity.

Example 12 A yellow toner 18 was obtained in the same manner as in Example 1, except that a chromium compound of di-tert-butylsalicylic acid was used instead of the zirconium compound of di-tert-butylsalicylic acid. . After the evaluation was performed in the same manner as in Example 1 using the yellow toner 18, the durability in a low-temperature and low-humidity environment showed a decrease in image density due to charge-up from around the 10,000th sheet. In the endurance, the charge amount was reduced from the 10,000th sheet and toner scattering and fogging were slightly observed, but both were within practical levels.

When the gloss and chromaticity of the image of the yellow toner 18 were examined in the same manner as in Example 1, the results shown in Table 5 were obtained.

[0228]

[Table 5]

[0229] Compared with the toner of Example 1, the yellow toner 18 has substantially the same image with higher gloss, but the brightness and the saturation are both lower. This is due to the poor dispersion of the colorant. It is thought that it is.

Although the transparency of an actual OHP image was not very good, it was within a practical level.

Examples 13 and 14, Comparative Example 7 Instead of the compound (I) used in Example 1, the following major axis /
Except for using the compound (I) having a short diameter ratio, the same procedure was repeated to obtain toners 19 to 21.

[0232]

[Table 6]

When the chromaticity of an image when each toner was used was examined in the same manner as in Example 1, the results shown in Table 7 were obtained. A durability test was also performed in the same manner.

[0234]

[Table 7]

Tables 8 and 9 show the toner formulations and evaluation results of the above Examples and Comparative Examples.

[0236]

[Table 8]

[0237]

[Table 9]

[0238]

As described above, the yellow toner of the present invention comprises a polyester having a specific acid value and a compound represented by the formula (I) as a colorant, and further comprises an aromatic carboxylic acid. When containing a derivative metal compound,
The dispersibility of the colorant in the toner is improved, good color reproducibility and charge stabilization can be achieved, and both the fixing property and the offset resistance can be satisfied.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an image forming apparatus using a yellow toner of the present invention.

FIG. 2 is a schematic diagram of an apparatus for measuring a triboelectric charge amount of a toner.

[Explanation of symbols]

 51 suction machine 52 measuring container 53 screen 54 lid 55 vacuum gauge 56 air flow control valve 57 suction port 58 condenser 59 electrometer

Claims (7)

[Claims] 1. A yellow toner having yellow toner particles containing at least a binder resin and a yellow colorant, wherein the binder resin is mainly composed of a polyester resin, and the acid value of the binder resin is 2 To 30 mgKOH / g, wherein the yellow colorant has a compound represented by the following formula (I): The primary particles of the yellow colorant have a ratio of the major axis to the minor axis of 3 or less, and the number average diameter of the yellow colorant present in the yellow toner particles is 0.1 to 0.5 μm. Yellow toner. 2. The binder resin has an acid value of 2 to 30 mgK.
2. The yellow toner according to claim 1, comprising an OH / g polyester resin as a main component. 3. The yellow toner according to claim 1, wherein the yellow toner has a negative charge property. 4. The yellow toner according to claim 1, wherein the yellow toner contains a metal compound of an aromatic carboxylic acid derivative. 5. The yellow toner according to claim 4, wherein the metal compound of the aromatic carboxylic acid derivative is a zirconium or aluminum-based metal compound. 6. The yellow toner contains an external additive, and the external additive has an average primary particle diameter of 0.002 to 0.5.
The yellow toner according to any one of claims 1 to 5, wherein the toner is a fine powder of titanium oxide or a fine powder of aluminum oxide of 2 µm. 7. The external additive has an average primary particle size of 0.00
7. The yellow toner according to claim 6, which is a titanium oxide fine powder or an aluminum oxide fine powder having a hydrophobicity of 2 to 0.2 [mu] m.