JP2001109194A - Yellow toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a yellow toner which has improved dispersion property of a coloring agent in the toner, which realizes good color reproducibility and electrification stability, and which satisfies both of the fixing property and offset resistance. SOLUTION: The yellow toner has yellow toner particles containing at least a binder resin, a yellow coloring agent and an organic metal compound. The binder resin essentially consists of a polyester resin and has 2.0 to 50.0 mgKOH/ g acid value. The yellow coloring agent is C.I.Pigment Yellow 180. The organic metal compound is an aluminum compound of benzilic acid expressed by formula (1) without substituted or having substituents. In the formula, each of R1 and R2 may be same or different and each represents a substituent selected from a group of straight-chain or branched alkyl groups, alkenyl groups, alkoxy groups, halogen atoms, nitro groups, cyano groups, amino groups, carboxyl groups and hydroxyl groups, and each of m and n is an integer 0 to 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yellow toner for developing an electrostatic image in electrophotography, electrostatic recording and electrostatic printing, and a yellow toner for forming a toner image in a toner jet image forming method. More particularly, 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.

In general, color image formation by full-color electrophotography uses three color toners of three primary colors, yellow, magenta, and cyan, or reproduces colors using four colors including black.

In the general color image forming method, an electrostatic latent image is formed on a photoconductive layer by passing light from an original through a color separation light transmitting filter having a complementary color relationship with the color of the toner. 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 of producing a toner while applying heat and pressure in a kneader. This method is more preferable for dispersing a colorant, but it is preferable to use a method for dispersing a toner. The molecular chains of the constituent binder resin are cut 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, since the three- or four-color toner is fixed in a layered state, the latitude of high-temperature offset resistance is much more severe than that of the black-and-white toner, and the number of molecules in the polymer is small. Cutting easily causes 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, dyes such as Solvent Yellow 112 in JP-A-2-207273, Solvent Yellow 160 in JP-A-2-207274, and Solvent Yellow 162 in JP-A-8-36275 are described. 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, although yellow pigments excellent in light resistance and heat resistance exist in addition to the above-mentioned pigments, on the other hand, they have too high a concealing property and extremely low transparency, so that they are not suitable for full color use. 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.
As described in JP-A-266163 and JP-A-8-262799, 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 No. 2632423 describes a toner in which a group of condensed 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 in transparency have been achieved, when viewed as a high-definition full-color yellow toner, the level of pigment dispersibility has not yet reached the target level. In the examination of (1), it was difficult to stabilize charging, and problems such as durability, low density, and fogging also occurred.

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 and 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 application of tribo to 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.

Today, polyester resins are widely used as binder resins for color toners in the technical field. However, color toners containing 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. Problems such as toner scattering are likely to occur, and toner spent on the carrier,
It causes various problems such as toner filming on the drum and fixing roller contamination. Therefore, improvement of the dispersibility of the colorant is an important technical issue other than the aspect of color reproducibility.

Further, a charge control agent is added to impart desired triboelectric charging characteristics to the toner.
As charge control agents, metal complex salts of monoazo dyes, metal complex salts of hydroxycarboxylic acids, dicarboxylic acids, aromatic diols and the like, resins containing an acid component, and the like are known.

However, most of these charge control agents are colored and many cannot be used for color toners. Most of the colorless, white, or light-colored toners applicable to color toners have insufficient performance. They have drawbacks such as lack of uniformity of highlights and large fluctuations in image density in a durability test.

Other points to be improved are that it is difficult to balance image density and fog, poor dispersibility in resin, and adversely affect storage stability, fixability, and offset resistance.

Conventionally, metal complexes and metal salts of aromatic carboxylic acids have been disclosed in JP-A-53-127726 and JP-A-57-127726.
JP-A-111541, JP-A-57-124357, JP-A-57-104940, JP-A-61-6
No. 9073, JP-A-61-73963, JP-A-61-267058, JP-A-62-10515
No. 6, JP-A-62-145255, JP-A-62-145255
JP-A-2-163601, JP-A-63-208865, JP-A-3-276166, JP-A-4-84
141 and JP-A-8-160668. However, these publications propose that although all of them are excellent from the viewpoint of imparting triboelectric charging, a simple developing device configuration enables stable development regardless of environmental changes, aging, and use conditions. Is rarely obtained. Also, there are few high-speed machines that can provide stable developability even during long-term durability. Further, there are many cases in which there is an influence of other raw materials and restrictions on other raw materials occur.

Conventional toners containing a boron compound of benzylic acid include those disclosed in JP-A-62-63491, JP-A-2-22167, JP-A-3-39973, and JP-A-5-72812. However, there is still room for improvement as a toner satisfying not only the charging performance but also the fixing property and the storage stability.

Further, Japanese Patent Application Laid-Open No. 9-124659 proposes a metal compound of an aromatic oxycarboxylic acid, but is not satisfactory in terms of long-term charging stability and environmental stability. .

Furthermore, Japanese Patent Publication No. Hei 7-104620 proposes a negatively chargeable charge exchange controlling agent containing boron. However, the developing method for obtaining the fluidity of the toner and a sufficient image density is proposed. There were many points to be improved in terms of properties, and they were not satisfactory in terms of long-term durability stability.

[0034]

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) Even with paper, the offset resistance is maintained, no wrapping around the fixing roller occurs, (6) there is no toner fusion to parts inside the developing device, that is, to the developing sleeve, blade, coating roller, etc., and (7) photosensitive No filming on the body surface, (8) good dispersibility of the colorant, (9) high coloring power, high image density, (10) high chroma, excellent transparency, (11) A) To provide a yellow toner which is excellent in light resistance and does not fade.

[0036]

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, a yellow colorant and an organometallic compound, wherein the binder resin comprises a polyester resin as a main component, Has an acid value of 2.0 to 50.0 mgKOH / g, and the yellow colorant has the following formula (I):

[0038]

Embedded image Wherein the organometallic compound is represented by the following formula (1):

[0039]

Embedded image (Wherein R ₁ and R ₂ may be the same or different and each represents a linear or branched alkyl group, alkenyl group, alkoxy group, halogen atom, nitro group, cyano group, amino group, carboxyl group, And m and n each represent an integer of 0 to 5), which is an unsubstituted or substituted benzylic acid aluminum compound represented by the following formula: Yellow toner.

[0040]

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
w180. 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 have found that the binder resin having a polyester resin as a main component and an unsubstituted or substituted group represented by the above formula (1) When using an organometallic compound of benzylic acid and aluminum, excellent pigment dispersibility is obtained, excellent transparency and a clear image are obtained,
It has been found that it functions as a full-color yellow toner. Further, they have found that excellent chargeability can be obtained by using a resin containing a polyester resin as a main component as a binder resin.

Further, by improving the dispersibility of the colorant, it also has an effect of preventing coloring from the toner, preventing contamination on the fixing roller and filming on the photoreceptor, and further preventing the toner from being applied to the carrier surface. Also works to prevent spent.

The reason that the aluminum compound of benzylic acid also functions to improve the dispersibility of the colorant is that, due to the interaction between the polyester resin and the aluminum compound of benzylic acid, a partial cross-linking reaction proceeds, and It is considered that by increasing such a share, the dispersibility of the colorant has been improved. Thereby, it is possible to contribute to improvement of the anti-offset property on the high temperature side while maintaining the rapid melting property on the low temperature side.

In addition, the partial skeleton of the aluminum compound of benzylic acid and the compound (I),

[0046]

Embedded image Interacts with each other to stabilize the dispersion by surrounding the compound (I) with a metal compound in the toner.

As a result, a yellow toner which can simultaneously satisfy all of the fixing property, color developing property and charging property required for full color can be obtained.

The aluminum compound of unsubstituted or substituted benzylic acid used in the present invention is an aluminum compound having 1 to 3 molecules of unsubstituted or substituted benzylic acid per 1 atom of aluminum. Therefore, the compound may be a complex or a complex salt. Further, in the present invention, a mixture containing an aluminum compound having one to three molecules of unsubstituted or substituted benzylic acid per atom of aluminum may be used.

The aluminum compound of benzylic acid of the present invention may contain less than 20% by weight of unsubstituted or substituted benzylic acid, which is not involved in the compound, based on the aluminum compound of benzylic acid. Good.

As the unsubstituted or substituted benzyl acid, a compound represented by the formula (1) is used.

[0051]

Embedded image (Wherein R ₁ and R ₂ may be the same or different and each represents a linear or branched alkyl group, alkenyl group, alkoxy group, halogen atom, nitro group, cyano group, amino group, carboxyl group, And m and n represent an integer of 0 to 5. Among them, unsubstituted benzylic acid (formula (2)) is preferred for the reaction stability and the absolute charge. It is preferable in terms of the value, image density stability, faithful color reproducibility and the like.

[0052]

Embedded image

Hereinafter, specific examples of the benzylic acid having a substituent used in the present invention will be described, but the present invention is not limited thereto.

[0054]

Embedded image

Next, the structural formulas of aluminum compounds of benzylic acid which are preferably used in the toner of the present invention are shown, but the present invention is not limited to these aluminum compounds of benzylic acid.

[0056]

Embedded image (Wherein X is a monovalent cation such as hydrogen, lithium,
Represents sodium, potassium, ammonium and alkylammonium. )

[0057]

Embedded image

The benzylic acid aluminum compound preferably used in the yellow toner of the present invention includes, for example, unsubstituted or substituted benzylic acid and aluminum salts such as aluminum sulfate (Al ₂ (SO ₄ ) ₃ ). Can be mixed at a desired molar ratio, and reacted by heating under an alkaline atmosphere, and the resulting precipitate can be collected by filtration, further washed with water, and dried. However, the method for producing the aluminum compound of benzylic acid according to the present invention is not limited to this.

As a method of incorporating the aluminum compound of benzylic acid of the present invention into the toner, there are a method of adding the compound to the inside of the toner and a method of adding it externally. When adding internally, a preferable addition amount is 0.1
It is used in the range of 10 to 10 parts by mass, more preferably 0.5 to 8 parts by mass. When externally added, 0.01 to 5
It is preferably a mass part, and in particular, it is preferably mechanochemically fixed to the toner surface. In the yellow toner of the present invention, it is preferable to add internally.

The aluminum compound of benzylic acid of the present invention can be used in combination with a conventionally known charge control agent. For example, other organometallic complexes, metal salts,
The chelate compound includes a monoazo metal complex, an acetylacetone metal complex, a hydroxycarboxylic acid metal complex, a polycarboxylic acid metal complex, and a polyol metal complex. Other examples include metal salts of carboxylic acids, carboxylic acid derivatives such as carboxylic acid anhydrides and esters, and condensates of aromatic compounds. Further, phenol derivatives such as bisphenols and calixarenes are also used.

Further, in the present invention, when a resin having an acid value of 2 to 50 mgKOH / g as a binder resin is used as a binder resin, excellent dispersibility and chargeability are obtained. 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 triboelectric charge amount of the toner is suppressed. In particular, when a resin having a specific acid value, which is mainly composed of a polyester resin, 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 is partially hydrogen-bonded or electrostatically bonded to the carbonyl group or imino group of the methyl ester or acetyl group of compound (I). 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 even under a high-temperature and high-humidity environment, a decrease in the triboelectric charge amount of the toner can be suppressed, And (ii) a polar group such as a carboxyl group or a hydroxyl group at the terminal of the molecular chain of the polyester resin is reduced, so that an excessive increase in the triboelectric charge amount of the toner even in a low-temperature and low-humidity environment can be suppressed. It is inferred.

In addition, the interaction between the polyester used in the present invention and the carbonyl group or imino group 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.

As a result, the chargeability of the toner tends to be stable, and the charge amount distribution is 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 a preferable spectral characteristic 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 180) represented by the formula (I) is usually composed of needle-like crystals in which the primary particles have an average ratio of the major axis to the minor axis of greater than 2.0. It has a morphology and contains many particles having a large primary particle diameter. 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.

In the present invention, the colorant represented by the compound (I) is finely treated so that the average value of the ratio of the major axis to the minor axis of the primary particles is 2.0 or less. When dispersed in a binder resin, a clear hue image is obtained, and in addition, the toner tends to be stable in terms of charge. In the present invention, there is no particular reference to the details of the pigment refining treatment.

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

When the number average particle diameter of the compound (I) in the toner is larger than 0.5 μm, the dispersibility of the pigment does not reach 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 the OHP sheet having a fixed image. 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, when a large amount of a colorant having a particle diameter larger than 0.5 μm is present, the yellow colorant is detached from the surface of the yellow toner particles, and various problems such as fog, drum contamination and poor cleaning are likely to occur. 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 mass, preferably 2 to 12 parts by mass, more preferably 3 to 10 parts by mass, per 100 parts by mass 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 mass part, the transparency is lowered, and in addition, the reproducibility of an intermediate color represented by a human skin color is liable to be 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 mass, 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) hardly fades and has excellent weather resistance.

In the present invention, the binder resin is mainly composed of a polyester resin. A polyester resin has excellent fixability when used as a binder resin for a toner, 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 (a)

[0078]

Embedded image (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 component, 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 binder resin has an acid value of 2.
An amount of 0 to 50.0 mgKOH / g, preferably 3.0 to 40.0 mgKOH / g is preferable because excellent charging stability can be obtained in each environment.

When the acid value of the binder resin is less than 2.0 mgKOH / g, the toner tends to charge up, and the image density tends to be low under 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 binder resin is 50.0 mgKOH / g
If it is larger, the stability over time of charging of the toner is reduced, and the charging amount is apt to be reduced along 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 binder resin is 50.0 mgK
When it is higher than OH / g, it becomes difficult to block the adsorption of water even when compound (I) is blended in the toner.

In the present invention, the glass transition temperature of the binder resin is from 50 to 68 ° C., preferably from 52 to 66 ° C., in consideration of the storability and fixability of the yellow toner and the color mixing with other color toners. Good to be.

When the glass transition temperature of the binder resin is lower than 50 ° C., although the fixing property is excellent, the offset resistance is lowered, and the fixing roller is contaminated and the fixing roller is wrapped. Further, the gloss of the image surface after fixing becomes too high, and the image quality deteriorates, which is not preferable.

When the glass transition temperature of the binder resin is higher than 68 ° C., the fixability deteriorates, and the fixing temperature of the copying machine must be increased, and the resulting image generally has low gloss. For a full-color toner, the color mixing property is reduced.

The binder resin used in the present invention preferably has a number average molecular weight (Mn) of from 1,500 to 20,000,
More preferably, 2,000 to 15,000, and the weight average molecular weight (Mw) is preferably 6,000 to 100,000.
0, more preferably 8,000 to 80,000,
Mw / Mn is preferably 2 to 10. A binder 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.

The number average molecular weight (Mn) of the binder resin is 1,5
When the weight average molecular weight (Mw) is less than 6,000
When the value is less than 0, the smoothness of the surface of the fixed image is high and the appearance of the image is vivid, but offset tends to occur in the durability, and the storage stability is deteriorated. There is also a concern about new problems such as fusion of the toner and generation of toner spent in which toner components adhere to the carrier surface. Further, it is difficult to apply a shear during the melt-kneading of the toner raw material 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.

The number average molecular weight (Mn) of the binder resin is 20,
000 or a weight average molecular weight (Mw) of 10
When it exceeds 000, all of them 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, even if the degree of dispersion of the colorant can be controlled, Surface smoothness is reduced,
The color reproducibility tends to decrease.

When the Mw / Mn of the binder 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, the offset phenomenon due to durability and the storage stability are stable. In addition, the toner is easily deteriorated, the toner is fused in the developing device, the toner is spent on the carrier, and the charge amount of the toner is apt to vary.

When Mw / Mn of the binder resin exceeds 10, although the offset resistance is excellent, the fixing temperature must be increased, and if the degree of dispersion of the colorant can be controlled. Also, 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 a polyester resin alone. However, it is preferable to mix the polyester resin with another resin, for example, an epoxy resin or a styrene-acrylic resin, or a polyester resin having different physical properties. May be used. The resin to be mixed is not particularly limited.

However, in the present invention, the polyester resin is preferably contained in an amount of at least 70% by mass, more preferably at least 80% by mass in all the resins constituting the toner. If the content is less than 70% by mass, 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, but the term “main component” refers to a case where the content is 70% by mass 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, an aliphatic hydrocarbon-based wax, an oxide of an aliphatic hydrocarbon-based wax,
Ester wax, fatty acid ester-based wax, saturated linear fatty acid, unsaturated fatty acid, saturated alcohol, polyhydric alcohol, fatty acid amide, saturated fatty acid bisamide, unsaturated fatty acid amide, aromatic Based bisamides.

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

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

These release agents are usually prepared by dissolving a binder resin in a solvent, raising the temperature of the resin solution, and adding and mixing the release agent with 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 material such as a hot roll, a kneader or an extruder is kneaded well with a toner kneading material, and then pulverized mechanically to classify the pulverized powder 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 particle diameter (D ₄ ) of the yellow toner is preferably from 4.0 to 10.0 μm, and more preferably from 5.0 to 9.0 μm.

When the weight average particle 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.

When the weight average particle diameter (D ₄ ) of the yellow toner exceeds 10.0 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, hydrophobic particles of titanium oxide or alumina having an average primary particle diameter of 0.001-0.2 μm are externally added to the yellow color toner particles as a fluidity improver. Good to be.

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 essential that the surface of the titanium oxide fine powder or the alumina fine powder is subjected to a hydrophobic treatment, whereby it is possible to simultaneously impart the fluidity and stabilize the charging. .

The titanium oxide fine powder or alumina fine powder is
Improving the environmental properties of yellow toner by eliminating the influence of moisture, which is a factor that affects the charge amount, and reducing the difference in charge amount under high and low humidity conditions due to the hydrophobic treatment Becomes possible. 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 hydrophobizing treatment step, and the external additive with less secondary agglomeration can more uniformly charge the yellow toner.

In the present invention, in particular, titanium oxide fine powder or alumina fine powder having an average primary particle diameter of 0.001 to 0.2 μm has good fluidity and uniform charging of the yellow toner, resulting in toner scattering and fog. Is preferred because it is less likely to occur. Further, the toner is hardly embedded on 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 a color toner having a sharp melt property.

When the average primary particle diameter of the hydrophobicized titanium oxide fine powder or alumina fine powder is less than 0.001 μm, the treated fine powder is easily buried in the surface of the yellow color toner particles, and the toner is deteriorated. It is easy to occur quickly and the durability tends to decrease. This tendency is more remarkable than when applied to a color toner having a sharp melt property.

When 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 fine alumina powder added is preferably 0.2 to 5.0% by mass, more preferably 0.3 to 3.0% by mass.
%, More preferably 0.5 to 2.5% by mass. 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 content of the titanium oxide fine powder or the alumina fine powder subjected to the hydrophobic treatment is 0.1%.
When the amount is less than 2% by mass, the fluidity of the toner is insufficient, so that the mixing property with the carrier is reduced, and fog and toner scattering are liable to occur at the time of durability.

If the content exceeds 5.0% by mass, filming on the surface of the photosensitive drum or poor cleaning is likely to occur due to the fine powder detached from the surface of the toner particles. Fog is also likely to occur.

The yellow toner of the present invention can be used as a two-component developer by mixing 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, iron, nickel, copper, zinc, surface oxidized or unoxidized.
Examples include metals such as cobalt, manganese, chromium, and rare earths, and magnetic alloys or oxides thereof and magnetic 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 amount of the material to be treated may be determined as appropriate, but is generally 0.1 to 30% by mass based on the total amount of the carrier.
(Preferably 0.5 to 20% by mass).

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 becomes stronger, the mixing property between the toner and the carrier is reduced, the chargeability of the toner is hardly stabilized, and the carrier 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, and the toner having a low charge amount is mixed, and fog is likely to occur. Further, since the toner tends to be scattered, it is necessary to set the toner concentration in the two-component developer at a low level, and an image having a 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 mass, more preferably 0.1 to 1% by mass
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 with respect to the yellow toner of the present invention can be obtained, and the effect of improving electrophotographic properties can be obtained.

When a two-component developer is prepared by mixing a yellow toner and a carrier, the mixing ratio is 2% by mass to 15% by mass, preferably 3% by mass to 13% by mass, as the toner concentration in the developer. %, More preferably 4% by mass to 1%
When it is 0% by mass, good results are usually obtained. If the toner density is less than 2% by mass, the image density tends to be low,
If the content is more than 20% by mass, 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 section is provided at an upper portion, and a digital color image printer section is provided at a lower portion.

In the image reader section, the original 30 is placed on an original platen glass 31 and is exposed and scanned by an exposure lamp 32, so that a reflected light image from the original 30 is condensed on a full color sensor 34 by a lens 33, and a color image is formed. 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 rotatably carried 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 devices 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, a suction charger 5c for electrostatically attracting a recording material and a suction roller 5g opposed thereto, and an inner charger 5g.
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 conveyed from the cassette 7a, 7b or 7c to the transfer drum 5a through a transfer sheet conveying 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 as the transfer drum 5a rotates, and is transferred onto the transfer material by the action of the transfer charger 5b in the process of passing through the transfer position. Is transferred onto the photosensitive drum 1.

As shown in FIG. 1, the toner image may be directly transferred from the photoconductor to the transfer material, or the toner image on the photoconductor may be transferred to the 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 onto which the four color toner images 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, and is heated and pressed by the fixing device. 9, where the toner is heated and pressurized and fixed to perform color mixing and color development of the toner and fixation to the transfer material. After forming a full-color fixed image, 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 to remove the powder adhered on the transfer sheet 5f and the oil adhered on the transfer sheet 5f. Such cleaning,
It is performed before or after image formation, and is performed as needed 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, a method for measuring each physical property will be described below.

Measurement of Particle Size Distribution of Toner A Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter Inc.) is used. The electrolyte is about 1% using primary grade sodium chloride.
Prepare an 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 electrolytic aqueous solution, and 0.1 to 5 ml.
ml, 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
Using a 00 μm aperture, the volume and number of toner particles are measured for each channel, and the volume distribution and number distribution of toner are calculated. Then, the weight average particle diameter (D4) of the toner on a weight basis determined from the volume distribution of the toner particles.
(The central value of each channel is set as a representative value for each channel).

As the channels, 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 to 12.70 μm; 12.70 to 16.
00 μm; 16.00-20.20 μm; 20.20
25.40 μm; 25.40-32.00 μm;
13 channels of 00 to 40.30 μm are used.

Method for Measuring Glass Transition Temperature of Binder Resin In the present invention, the glass transition temperature is measured using a differential thermal analyzer (DSC analyzer), 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 Binder Resin Mn, Mw and Mw / Mn of the binder resin are measured by gel permeation chromatography (GPC). Stabilize the column in a 40 ° C. heat chamber,
At this temperature, tetrahydrofuran (THF) is flowed as a solvent at a flow rate of 1 ml / min into the column, and about 100 μl of a THF sample solution is injected to measure. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Tosoh Corporation or Showa Denko KK having a molecular weight of about 10 ² to 10 ⁷ is used, and it is appropriate to use a standard polystyrene sample of at least about 10 points. is there. An R1 (refractive index) detector is used as the detector. As the column, it is preferable to use a plurality of commercially available polystyrene gel columns in combination.

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.

The sample is prepared as follows.

After placing the sample in THF and leaving it to stand for several hours, it is shaken well, mixed well with THF (until the sample is no longer united), and allowed to stand still 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 acid value 2 to 10 g of a sample are weighed in a 200 to 300 ml Erlenmeyer flask, and about 50 ml of a mixed solvent of methanol: toluene = 30: 70 is added to dissolve the resin. If the 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 (ml number) × N × 56.1 /
Sample weight (N is a factor of N / 10KOH)

The method of measuring the triboelectric charge of the toner The method of measuring the triboelectric charge of the toner will be described below for a two-component developer and a one-component developer.

(Two-Component Developer) FIG. 2 is an explanatory view of an apparatus for measuring the triboelectric charge. 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
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.

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

The developer collecting device used in the suction type Faraday cage method has a suction device portion for sucking air and a collecting device portion 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 an inner cylinder having a cylindrical filter paper for collecting the sucked developer.

In order to specifically collect and collect the developer on the developing sleeve by 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 cylindrical filter paper from which the developer was recovered was weighed,
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 inner cylindrical filter paper 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 particle size is measured by XMA, and the average particle size is determined.

Measurement Method of Average Particle Size of Carrier The carrier was measured using a Microtrac particle size analyzer SRA type (manufactured by Nikkiso Co., Ltd.) at a setting 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 major and minor 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. By measuring 300 pigment particles of 1 μm or more,
The ratio of the average value is taken as the ratio of the major axis to the 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 particle diameter Yellow toner or yellow toner particles are added to a 2.3M sucrose solution, stirred well, put in a small amount in a sample holder bottle, and then poured into liquid N ₂ to be solidified. Set to.

A sample is prepared by cutting with an ultramicrotome FC4E equipped with a cryo-apparatus (manufactured by Nissan Sangyo) according to a conventional method.

A photograph was taken at an acceleration voltage of 100 kV using an electron microscope Model H-8000 (manufactured by Hitachi, Ltd.). The magnification is 30,000 to 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. Of these, only the pigment particles having a primary particle size and a secondary particle size of 0.1 μm or more are analyzed at random, and the number of samples is 30
The measurement is repeated until the number exceeds 0, and the number average particle size of the pigment particles is determined.

Here, only the primary and secondary particles of the yellow colorant larger than 0.1 μm are measured.
The number average particle size referred to 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 average value of the ratio of the major axis to the minor axis of the primary particles of the colorant in the toner particles can be similarly measured from pigment particles having a primary particle diameter of 0.1 μm or more.

[0170]

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

Example 1 Polyester Resin No. 170 parts by mass [Polyester resin produced from polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane terephthalic acid fumaric acid trimellitic acid (acid value 12.0 mgKOH / g, Tg = 57 ° C., Mn = 3900, Mw = 12700, Tm = 93 ° C.) 30 parts by weight of yellow pigment represented by the following structural formula (ratio of major axis to minor axis of primary particles = 1.5)

[0172]

Embedded image

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.

16.7 parts by mass of the above kneaded material (pigment particle content: 30 parts by mass) 188.3 parts by mass-Aluminum compound A of benzylic acid 4 parts by mass (compound consisting of one atom of aluminum and two molecules of benzylic acid)

The above materials were sufficiently premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely ground to about 1 to 2 mm using a hammer mill, and then finely ground by an air jet method. And pulverized.
Further, the obtained finely pulverized material was strictly and simultaneously removed with a multi-segmentation classifier to obtain yellow color toner particles having a weight average diameter of 7.5 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
₃ of nC ₄ H ₉ —Si (OCH ₃ ) ₃ with respect to 00 parts by mass
Surface treatment using 0 parts by mass and a primary average particle size of 0.0
Hydrophobic titanium oxide fine powder B having a particle size of 2 μm and a hydrophobicity of 74% was obtained.

By mixing 100 parts by mass of yellow color toner particles and 1.5 parts by mass of hydrophobic titanium oxide fine powder B, yellow toner 1 having hydrophobic titanium oxide fine particles on the surface of yellow color toner particles was prepared.

The magnetic ferrite carrier particles (average particle size: 4
0 μm) to obtain a two-component yellow developer.

The above two-component yellow developer was used in a commercial 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 end of 50,000 sheets, no filming due to toner fusion 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 even 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, toner spent was hardly 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.

Next, instead of the yellow pigment, C.I. I.
Pigment Blue 15: 3 was used in the same manner except that 4 parts by mass was used, and the weight average diameter was 7.5 μm.
m cyan color toner particles were obtained.

Further, C.I.
I. Pigment Red 122 is used in the same manner except that 5 parts by mass 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, 1.5 parts by mass of hydrophobic titanium oxide fine powder B were mixed in the same manner as in the case of the yellow toner. 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.

[0189]

(Equation 1) 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, set to 6V with a constant voltage device, then adjust the light projection angle and light reception angle to 60 °, respectively, and use the zero point adjustment and the standard plate. The measurement was performed by superimposing three sheets of paper, and the numerical value indicated in the marked part was read in%.

The color tone of the toner was quantitatively measured based on the definition of a 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 °.

In Example 1, the gloss and chromaticity of each image were as shown in Table 1 below.

[0193]

[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 yellow toner on a transparency film using a commercially available overhead projector. did.

(Evaluation Criteria) A: Excellent in transparency, no unevenness in brightness and darkness, 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 (1. 67), and the hue change was also slight (ΔE = 2.8). The light source used was an ultraviolet carbon arc lamp.

The change in hue was determined by calculating the ΔE value of the following formula and quantitatively evaluating it 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 Indicated chromaticity 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: No fading 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) propane Terephthalic acid Fumaric acid Trimellitic acid Condensation polymer (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: 7.4 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 The polyester resin No. used in Example 1 Polyester resin No. 1 3 [Polyoxypropylene (2.2) -2,2-bis (4
-Hydroxyphenyl) propane terephthalic acid fumaric acid trimellitic acid condensation polymer (acid value 52.0 mgKOH / g,
Tg = 55 ° C., Mn = 4800, Mw = 11000, T
m = 93 ° C.), except that yellow toner 3 (weight average diameter 7.5 μm) was used in the same manner as in Example 1.
I got 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 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, Tm: 94 ° C.), except that yellow toner 4 (weight average diameter: 7.5 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 was used. Instead of 1,
Polyester resin No. 5 (condensation polymer of propoxylated bisphenol A and fumaric acid, acid value: 46.2 m
gKOH / g, Tg: 55 ° C., Mw: 11,000, M
n: 3800, Tm: 89 ° C.), and a yellow toner 5 (weight average diameter: 7.4 μm) was obtained in the same manner as in Example 1. Using yellow toner 5,
Evaluation was made in the same manner as in Example 1. As a result, although the charge amount was slightly reduced in a high-temperature and high-humidity environment, 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 zero, Tg = 60 ° C., Mn = 5200, Mw = 220
00, Tm = 96 ° C.)], except that yellow toner 6 (weight average diameter: 7.4 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.

[0207]

[Table 2]

As shown in Table 2, the lightness and the saturation of the yellow toner 6 were reduced.

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.

[0210]

[Table 3]

Comparative Example 4 The following formula (II) was used in place of the coloring agent used in Example 1.

[0212]

Embedded image (II) (CI Pigment)
Yellow 12, the ratio of the major axis to the minor axis of the primary particles = 2.
4) is a polyester resin No. A yellow toner 7 was prepared in the same manner as in Example 1 except that 5 parts by mass was used per 100 parts by mass, and evaluated in the same manner as in Example 1. Although the durability changed relatively stably under each environment,
The obtained yellow image faded in the light resistance acceleration test of carbon arc lamp irradiation (ΔE = 12 after 100 hours of light irradiation). The number average particle size of the colorant in the toner was 0.22 μm.

Example 4 Instead of the hydrophobic titanium oxide fine powder B used in Example 1,
Hydrophilic alumina fine powder C (primary average particle size: 0.02μ)
m, BET specific surface area: 130 m ² / g) 100 parts by mass of iso-C ₄ H ₉ —Si (OCH ₃ ) ₃ with 17 parts by mass for surface treatment, primary particle diameter 0.02 μm, hydrophobization A hydrophobic alumina fine powder D having a degree of 70% was obtained. A yellow toner 8 was prepared in the same manner as in Example 1 except that the hydrophobic alumina 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 In place of 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 -14 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 4 mC / kg as compared with that before the standing. In addition, the degree of toner scattering and fogging tended to be deteriorated along with the durability, but it was within a practical level.

Example 6 Instead of the hydrophobic titanium oxide fine powder B used in Example 1,
Hydrophilic silica E (primary average particle size: 0.005 μm, B
(ET specific surface area: 380 m ² / g) A 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 mass of hexamethyldisilazane with respect to 100 parts by mass. A yellow toner 10 was obtained in the same manner as in Example 1 except for the above. Evaluation was performed in the same manner as in Example 1 using the yellow toner 10. In endurance in a low-temperature and low-humidity environment, the charge amount of the toner starts to increase around the 3,000th sheet, the image density starts to decrease,
Although the image was rough, it was within practical use.

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 endurance in a high-temperature and high-humidity environment, fog and toner scattering tended to worsen with endurance, but were within practical levels.

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

[0220]

Embedded image (III) (CI Pigment)
Yellow 95, ratio of major axis to minor axis of primary particles = 3.
A yellow toner 11 was obtained in the same manner as in Example 1 except that 4) was used in an amount of 5 parts by mass with respect to 100 parts by mass of the polyester resin, and was evaluated in the same manner as in Example 1. The density was also high (1.60), which was within a practical level, but the image density gradually decreased during many-sheet running. That is, the image density after the durability of 10,000 sheets is 1.2.
It had dropped to zero. The number average particle size of the colorant in the toner was 0.54 μm.

Comparative Example 6 A yellow toner 12 was obtained in the same manner as in Example 1, except that the following iron-based compound D was used instead of the aluminum compound A of benzylic acid.

[0222]

Embedded image

After the evaluation using the yellow toner 12 in the same manner as in Example 1, the durability in a low-temperature and low-humidity environment shows a decrease in image density due to charge-up from around the 5000th sheet. In the durability under the condition, the charge amount decreased from around the 3000th sheet, and slight toner scattering and fogging were observed.

When the gloss and chromaticity of the image of the yellow toner 12 were examined in the same manner as in Example 1, the results shown in Table 4 were obtained.

[0225]

[Table 4]

Compared with the toner of Example 1, the yellow toner 12 has low lightness and low chroma, although the gloss of the same image is relatively high. This is due to poor dispersion of the colorant. It is thought that there is.

The transparency of the actual OHP image was not very good.

Example 7 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 mass of nC ₄ H ₉ —Si (OCH ₃ ) ₃ with 10 parts by mass of surface treated, primary particle diameter 0.22 μm, degree of hydrophobicity 68
% Of hydrophobic titanium oxide fine powder H was used, and toner 13 was prepared in the same manner as described above and evaluated for durability.

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

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

Example 8 In substantially the same manner as in Example 1, yellow toner particles having a weight average diameter of 10.4 μm were obtained. 0.8 parts by mass of hydrophobic titanium oxide fine powder B as an external additive was mixed with 100 parts by mass of yellow toner particles to prepare a yellow toner 14.

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

Example 9 In substantially the same manner as in Example 1, yellow toner particles having a weight average diameter of 3.9 μm were obtained. Yellow toner 15 was prepared by mixing 1.5 parts by mass of hydrophobic titanium oxide fine powder B as an external additive with 100 parts by mass of yellow toner particles.

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

Examples 10 to 11 In place of the compound (I) used in Example 1, the following diameter /
Except for using the compound (I) having a minor axis ratio, the toner was converted to toner in the same manner to obtain toners 16 to 17.

[0236]

[Table 5]

When the chromaticity of the image when each toner was used was examined in the same manner as in Example 1, the results shown in Table 6 were obtained.

[0238]

[Table 6]

The endurance results of Toners 16 and 17 are shown in Table 9. Good results were obtained with Toner 16. Although the transparency of OHP of toner 17 was reduced, it was within a practical level.

Comparative Example 7 A yellow toner 18 was obtained in the same manner as in Example 1, except that the chromium compound E was used instead of the benzylic acid aluminum compound A.

[0241]

Embedded image

After the evaluation using the yellow toner 18 in the same manner as in Example 1, the endurance in a low-temperature and low-humidity environment showed a decrease in image density due to charge-up from around the 10000th sheet. In the lower durability, the charge amount decreased from about the 10,000th sheet, and some toner scattering and fogging were observed, but both were within the practical level. When the chromaticity was examined in the same manner as in Example 1, the results shown in Table 7 were obtained.

[0243]

[Table 7]

As compared with Example 1, the saturation was greatly reduced. The transparency of the actual OHP image was not very good. The color was also bad.

Example 12 Instead of aluminum compound A of benzylic acid used in Example 1, a compound consisting of one atom of aluminum and one molecule of benzylic acid (aluminum compound B of benzylic acid) was added to 100 parts by mass of polyester resin. Except for using 4 parts by mass, a weight average diameter of 7.
When a 9 μm yellow toner 19 was obtained and evaluated in the same manner as in Example 1, good results as shown in Table 9 were obtained.

Example 13 In place of aluminum compound A of benzylic acid used in Example 1, a compound consisting of 2 atoms of aluminum and 3 molecules of benzylic acid (aluminum compound C of benzylic acid) was added to 100 parts by mass of polyester resin. Except for using 4 parts by mass, a weight average diameter of 7.
When an 8 μm yellow toner 20 was obtained and evaluated in the same manner as in Example 1, good results as shown in Table 9 were obtained.

[0247]

[Table 8]

[0248]

[Table 9]

[0249]

As described above, the yellow toner of the present invention comprises a polyester having a specific acid value and a compound represented by the above formula (I) as a coloring agent. When the compound is contained, 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

Continued on the front page. (72) Inventor Iku Iku, 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Makoto Shinbayashi 3-30-2, Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. F term (reference) 2H005 AA01 AA06 AA08 AA21 CA08 CA21 CA25 CA26 CB07 DA02 DA04 DA06 DA10 EA05 EA10

Claims (4)

[Claims] 1. A yellow toner having yellow toner particles containing at least a binder resin, a yellow colorant and an organometallic compound, wherein the binder resin has a polyester resin as a main component, and the acid value of the binder resin is 2.0 to 50.0 mgKOH / g, and the yellow colorant is represented by the following formula (I): Wherein the organometallic compound is represented by the following formula (1): (Wherein R ₁ and R ₂ may be the same or different and each represents a linear or branched alkyl group, alkenyl group, alkoxy group, halogen atom, nitro group, cyano group, amino group, carboxyl group, And m and n each represent an integer of 0 to 5), which is an unsubstituted or substituted benzylic acid aluminum compound represented by the following formula: Yellow toner. 2. The primary particles of the yellow colorant have an average ratio of the major axis to the minor axis of 2.0 or less, and have a number average diameter of the yellow colorant present in the colorant-containing resin particles. 2. The yellow toner according to claim 1, wherein the thickness is 0.1 to 0.5 [mu] m. 3. The toner has an average primary particle size of 0.001.
The yellow toner according to claim 1, further comprising a titanium oxide or alumina having a hydrophobicity of 0.2 μm or less. 4. The toner has a weight average particle diameter of 4 to 10 μm.
4. The yellow toner according to claim 1, wherein m is m.