JP2000081734A - Magenta toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner which shows good hue and excellent color reproducibility, which suppresses decrease in triboelectric charges of the toner in a high temp. and high humidity environment, which suppresses extra triboelectric charges in a low temp. and low humidity environment and which has excellent environmental stability, and to form an image having excellent light resistance by using a specified polyester resin as a binder resin and using a specified magenta coloring agent. SOLUTION: The binder resin used is a polyester resin having 2 to 25 mgKOH/g acid value, and the magenta coloring agent is a compd. expressed by the formula. Titanium oxide fine powder or aluminum oxide fine powder having 0.01 to 2 μm average primary particle diameter and subjected to hydrophobic treatment is externally added to the magenta color toner particles. The magenta toner has 3 to 15 μm weight average particle size. In the formula, each R1 to R4 is one of OCH3, halogen group, H or the like. The compd. expressed by the formula is preferably compounded by 1 to 15 pts.wt. to 100 pts.wt. of the binder resin in the toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magenta toner applied to electrophotography, electrostatic recording, electrostatic printing, toner jet recording, and the like.

[0002]

2. Description of the Related Art With the recent reduction in the price of computer equipment intended for personal users, a video communication system using video has become widespread in full color from the visual world. Under such needs, full-color image forming apparatuses such as printers and copiers, which are one of the output means, are rapidly becoming full-colored, mainly in the low-grade machine market, and color images are more familiar to general users. It is becoming something.

As such full-color output devices, there are generally many methods such as a thermal transfer system, an ink ribbon system, and an ink-jet system, but as a whole, electrophotographic systems occupy the majority. In general, an electrophotographic system uses a photoconductive substance to form an electric latent image on a photoreceptor by various means, and then develops the latent image using a toner, and if necessary, forms a transfer material such as paper. After transferring the toner image, the toner image is fixed by heating, pressurizing, heating and pressurizing or solvent vapor to obtain a color image.

In the case of full color, the three primary colors of the color material, namely yellow toner, magenta toner and cyan toner, are used.
The color reproduction is performed using four color toners including a chromatic color toner or a black toner. For example, an electrostatic latent image is formed on the photoconductive layer by passing light from a document through a color separation light passing filter that has a complementary color relationship with the color of the toner. Next, the color toner is held on the support through a development step and a transfer step. Next, the above-described steps are sequentially performed a plurality of times, and while the registration is being performed, the color toners are superimposed on the same support, and a final full-color image is obtained by fixing.

In recent years, demands for higher image quality and higher definition in full-color images have been increasing. 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, realization of uniformity of a solid image over a wide image area in a copied image, uniformity of a halftone image, and a wide dynamic range from high density to low density is desired.
There has been an urgent need to develop a toner capable of outputting a high image density, a toner having a color tone similar to that of printing, a toner having excellent OHP transparency (light transmittance), and a toner having excellent light resistance.

Accordingly, as a coloring agent used in a toner, naturally, a coloring agent having high coloring power, excellent color clarity and transparency, excellent light resistance, and excellent dispersibility in a resin. The fact is that agents are strongly desired.

On the other hand, as the number of cases where a color copying machine is connected to a computer via a controller and used as a high-quality color printer has increased, a color management system for managing the color of the entire system has been proposed. As a result, certain users strongly desire that the output image output by the electrophotographic color copier match the output image of the printing based on the process ink in terms of tint, A toner having the same color tone as described above has also been required.

Although several pigments have been proposed as magenta toner pigments, they have excellent color clarity and transparency.
In addition, quinacridone pigments have been widely used because they are excellent in light resistance.

JP-A-49-27228, JP-A-57-5
4954 and JP-A-1-142559, etc.
A toner containing only 9-dimethylquinacridone is disclosed. Although this toner was excellent in light resistance, it was hardly a sufficiently vivid magenta toner.

Japanese Patent Application Laid-Open No. 64-9466 discloses that a combination of a quinacridone pigment and a xanthene dye or a pigment obtained by raked a xanthene dye is used to improve the vividness of the toner. This toner has not yet obtained sufficient vividness, and has a problem that the color changes and the image is discolored when the image is left for a long time.

JP-A-1-154161 discloses the use of a quinacridone pigment having an average particle size of 0.5 μm or less in order to improve the transparency of magenta toner. The transparency of the toner is determined by the pigment and resin, and the method and degree of dispersion in the resin.
A highly transparent magenta toner has not always been obtained.

On the other hand, in the case of a full-color image, color reproduction is carried out with three chromatic color toners of three primary colors of a yellow toner, a magenta toner, and a cyan toner, or four color toners including a black toner. In order to obtain an image having a desired color tone, the balance with other colors is important, and attempts have been made to slightly change the color tone of magenta toner.

For example, JP-B-63-18628 discloses a mixture of compounds containing two kinds of substituted quinacridones, and JP-A-62-291669 discloses a mixture of 2,9-dimethylquinacridone and It describes that a mixed crystal with unsubstituted quinacridone is used as a colorant for magenta, has a desired hue, and has been proposed as a colorant for the purpose of also improving the triboelectric charging property of a toner. .

However, although the color shifts in the direction of reddish as a whole as compared with the case where 2,9-dimethylquinacridone is used alone, the bluish color is stronger than the hue of the magenta ink for offset printing. There were many points to be improved.

On the other hand, many studies have been made for the purpose of improving the dispersibility of the colorant present in the toner.

JP-A-61-117565 and JP-A-61-156054 disclose a method in which a binder resin, a colorant and a charge control agent are dissolved in a solvent in advance, and the solvent is removed to obtain a toner. Although these are disclosed, they have problems that it is difficult to control the dispersibility of the charge control agent, and that the solvent remains in the final product toner and gives an undesirable odor.

Japanese Patent Application Laid-Open No. 61-91666 discloses a method for producing a toner using a halogen-based solvent. This production method is used because the halogen-based solvent has a strong polarity. There is a disadvantage that the colorant is limited.

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. Such a method is more preferable for dispersing a colorant, but the method for dispersing a toner is preferred. 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 full-color copying, the latitude of high-temperature offset resistance is much more severe than that of black-and-white toner, because the toner of three or four colors is fixed in a layered manner. It easily causes hot offset.

JP-A-5-34978 discloses that a resin and an aqueous presscake of a pigment are charged in a kneading machine and kneaded with heat to achieve dispersion of the pigment in the resin. However, there is no mention of pigments that take into account the tint and color reproducibility of the toner.

In general, 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. To develop an electrostatic charge 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 problems, search for a carrier core material and a carrier coating material and optimize the coating amount, or study a charge control agent and a fluidity imparting agent to be added to the toner, and furthermore, become a base material. Many studies have been made to achieve excellent triboelectrification in a material constituting a developer, such as improvement of a binder.

In recent years, in order to meet the demand for higher definition and higher image quality of a copying machine or a printer, attempts have been made in the art to reduce the particle size of the color toner to achieve higher image quality and color. 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 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 particular, the following characteristics are strongly desired for color toners. (1) It is important for the fixed color toner to be in a state close to almost complete melting such that the shape of the toner particles cannot be distinguished so that the color toner does not diffusely reflect light and hinder color reproduction. (2) It is important that the color toner has a transparency that does not hinder the toner layers of different colors below the toner layer. (3) It is important that each of the constituent color toners has balanced hue and spectral reflection characteristics and sufficient saturation.

From this point of view, many studies have been made on binder resins, and color toners satisfying the above-mentioned characteristics have been desired. Today, polyester resins are widely used as binder resins for color toners in the art, but color toners having polyester resins are generally susceptible to temperature and humidity, and have an excessive charge amount under low humidity and high charge. A problem such as insufficient charge amount under humidity is likely to occur, and development of a color toner having a stable charge amount even in a wide range of environments is expected.

[0026]

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

That is, the object of the present invention is to (1) have a high coloring power covering a wide dynamic range from low density to high density, (2) have high chroma and lightness, and (3) OHP
An object of the present invention is to provide a magenta toner having excellent transparency, (4) excellent dispersibility of a colorant, (5) having high light fastness, and (6) having a color tone matching that of the process ink.

It is another object of the present invention to provide (7) good fixability and color mixing, (8) stable and always triboelectric charging, which is hardly influenced by environment such as temperature and humidity.
(9) High gloss to enhance image quality, (10) High-temperature offset is sufficiently prevented, fixable temperature is wide, (1)
1) To provide a magenta toner which has no toner fusing in a developing device, that is, components such as a sleeve, a blade, and an application roller, and which has good cleaning properties and does not film on a photoreceptor. is there.

It is a further object of the present invention to provide a magenta toner which has (13) no fog, (14) excellent highlight reproducibility, (15) excellent solid uniformity, and (16) excellent durability stability. Is to do.

A further object of the present invention is to provide a magenta toner which is excellent in fluidity, development fidelity and transferability.

[0031]

The present invention provides a magenta toner having magenta color toner particles containing at least a binder resin and a magenta colorant, wherein the binder resin has an acid value of 2 to 25 mgKOH / g. A polyester resin, wherein the magenta colorant has the following formula (I):

[0032]

Embedded image(Where R ₁, R _Two, R _Three, R _FourIs OCH_Three,halogen
Group, H, OH, NO_Two, OC_TwoH_Five, Alkyl group, NH_Two,
N (CH_Three)_Two, NHCOCH_ThreeIndicates one of )so
The magenta color toner particles
Is subjected to a hydrophobic treatment with an average primary particle diameter of 0.01 to 2 μm.
Titanium oxide fine powder or aluminum oxide fine powder
The magenta toner has a weight average particle size of 3 to 3.
Magenta toner having a size of 15 μm
You.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies on a magenta colorant applicable to magenta toner, and found that the following formula (I) is used as a magenta colorant.

[0034]

Embedded image(Where R ₁, R _Two, R _Three, R _FourIs OCH_Three,halogen
Group, H, OH, NO_Two, OC_TwoH_Five, Alkyl group, NH_Two,
N (CH_Three)_Two, NHCOCH_ThreeIndicates one of )so
(Hereinafter referred to as "compound (I)")
Magenta toner with good hue
And the compound (I) is a color toner
Has a remarkable effect on the charge stabilization, especially as a binder resin.
When using polyester resin, the effect is very
It was found to be author. Detailed explanation below
I will tell.

The compound (I) used in the present invention can be synthesized from a β-naphthol derivative represented by the following formula (1), (2) or (3). Further, the present invention is not limited to this method.

[0036]

Embedded image

The compound (I) used in the present invention is a chromatic pigment excellent in weather resistance, has good dispersibility in a binder resin, and can prepare a magenta toner having a vivid hue.

On the other hand,

[0039]

Embedded image 2,9-dimethylquinacridone (hereinafter, referred to as compound (V)) represented by the above structural formula shows a vivid magenta color, and when this is used as a colorant for a toner, a toner having high coloring power can be obtained. . However, when compared with the magenta hue of the process ink, it has the characteristic of having a strong blue tint.

As a magenta pigment for process inks, carmine-based pigments have been widely used so far.
Some examples of applying this to toner have been reported.
However, carmine pigments have poor light fastness, and the difference is obvious when compared with quinacridone pigments.

The present inventors have conducted intensive studies on a magenta toner which is excellent in light fastness, has high lightness and chroma, and has a wide color reproducibility, and which has a magenta hue of a process ink. It has been found that the above object can be achieved when (I) is used.

This cannot be achieved by a conventionally used blend of, for example, a carmine-based red pigment and 2,9-dimethylquinacridone, when higher brightness and higher chroma are desired.

Further, the toner of the present invention has excellent light fastness,
JIS K
When a long-term exposure test was carried out substantially according to 7102, little change in color was observed.

The degree of color change was quantitatively evaluated by ΔE in the following equation.

[0045]

(Equation 1)

A magenta toner containing the compound (I) as a magenta colorant (pigment) exhibits a hue shifted to reddish, and has a preferable spectral characteristic as a magenta toner for full-color image formation. Further, compound (I)
The magenta toner containing the colorant has high lightness and high saturation. The reproducibility of human flesh color is important in a full-color image, but the use of a magenta toner containing compound (I) makes it possible to reproduce human flesh color well, and the overhead projector (OHP)
Even when a color image formed on the sheet is projected, the transparency is excellent. Further, the magenta toner containing the compound (I) has a stable image density even at the time of running many sheets, and a clear image without fog can be obtained for a long period of time.

In the toner of the present invention, the compound (I)
Is preferably 1 to 15 parts by weight, preferably 3 to 12 parts by weight, more preferably 4 to 10 parts by weight, based on 100 parts by weight of the binder resin. When the amount is less than 1 part by weight, the coloring power of the toner is reduced, and it is difficult to obtain a high-quality image with a high image density even if the dispersibility of the pigment is improved. On the other hand, when the amount is more than 15 parts by weight, the transparency of the toner decreases, and the transparency of the trapene decreases. In addition, the reproducibility of intermediate colors, as represented by human flesh colors, also decreases. Further, the chargeability of the toner becomes unstable, causing problems such as fog in a low-temperature and low-humidity environment and toner scattering in a high-temperature and high-humidity environment.

In the present invention, it is preferable to use a polyester resin as the binder resin. This is because the 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. However, by using the compound (I), the adverse effect is improved and an excellent magenta toner can be obtained.

That is, the toner using the compound (I) exhibits an effect of preventing an excessive charge amount in a low-temperature and low-humidity environment and suppressing a decrease in the charge amount in a high-temperature and high-humidity environment.

Although the reason is not clear, a partial hydrogen bond or an electrostatic bond between a carboxyl group or a hydroxyl group at the terminal of the polyester and a hydroxyl group or a carbonyl group in the compound (I) molecule is caused. It is considered that the compatibility between the binder resin and the pigment is increased, and as a result, the dispersibility of the colorant is improved and the charging is stabilized.

The suppression of the decrease in the amount of charge under high temperature and high humidity is because the pigment blocks the adsorption of water to the functional group at the terminal of the binder resin because of the good pigment dispersibility described above. It is expected that a high charge amount can be obtained and stable even in a humid environment.

Therefore, when a polyester resin is used as the binder resin, a high-quality image with stable image density without fog can be obtained in long-term durability.

In particular, the following equation

[0055]

Embedded image (Wherein R is an ethylene or propylene group, x, y
Is an integer of 1 or more, respectively, and the average value of x + y is 2 to 10. A) a carboxylic acid component comprising a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, phthalic acid) Acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) are more preferred because they have sharp melting properties.

Particularly, the acid value of the polyester resin is 2 to 25 m.
When it is gKOH / g, excellent charging stability can be obtained in each environment.

That is, when the acid value is less than 2 mg KOH / g, the toner tends to charge up and the image density tends to be low under a low temperature and low humidity environment.

On the other hand, when the acid value is larger than 25 mgKOH / g, the charge stability with time is poor, and the charge amount tends to decrease with the endurance. Particularly in an environment of high temperature and high humidity, image defects such as toner scattering and fogging occur. It will be easier.

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 10,000 to 90,00
0, 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 fluctuation of the charge amount of the 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 smoothness of the fixed image surface is high and the appearance is vivid, but offset occurs in the 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, it is difficult to apply a shear at the time of melting and kneading the toner raw materials at the time of producing the magenta color toner particles, and the dispersibility of the magenta colorant is easily reduced, so that 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, the offset phenomenon due to durability and the storage stability are similar. , 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.

The magenta toner of the present invention may further contain a charge control agent as required. Examples of the charge control agent include a metal compound of an aromatic carboxylic acid derivative. Preferably, metal salicylate, metal salicylate, metal alkylsalicylate, metal alkylsalicylate, metal dialkylsalicylate, metal dialkylsalicylate are preferable. As the metal element, chromium, aluminum and zinc are preferable.

When these charge control agents are contained in the magenta color toner particles, the content is preferably 3 to 1
The range of 0% by weight, preferably 4 to 8% by weight is suitable, but the range is not necessarily limited in the magenta toner as long as the range does not affect the color tone.

When a charge control agent is used in the above content, the initial variation of the charge amount is small, and the absolute charge amount required during development is easily obtained. As a result, image quality such as fogging and image density reduction is not impaired, which is preferable. .

In the magenta 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 magenta color toner particles 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 magenta color toner particles is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 1 part by weight, per 100 parts by weight of the binder resin.
0 parts by weight is good. When the content of the release agent is more than 20 parts by weight, the blocking resistance and the high-temperature offset resistance are apt to decrease, and when the content is less than 0.1 part by weight,
Low release effect.

It is preferable that these release agents are usually contained in the binder resin by dissolving the resin in a solvent, increasing the temperature of the resin solution, and adding and mixing while stirring, or by mixing at the time of kneading. .

In producing magenta color toner particles, a method of kneading the constituent materials well by a heat kneading machine such as a hot roll, kneader, extruder and the like, mechanically pulverizing, and classifying coarse pulverization to obtain a toner; A method in which a 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 size of the magenta toner is preferably 3 to 15 μm, and more preferably 4 to 12 μm. If the weight average particle size of the magenta toner is less than 3 μm, it is difficult to achieve stable charging, and
Fog and toner scattering are likely to occur. When the weight average particle size of the magenta toner exceeds 15 μm, the reproducibility of the halftone portion is greatly reduced, and the obtained image becomes a rough image.

In the magenta toner of the present invention, hydrophobically treated titanium oxide fine powder or aluminum oxide fine powder having an average primary particle diameter of 0.01 to 2 μm is externally added to the magenta color toner particles as a fluidity improver. Good to be.

In the fluidity improver as an external additive,
Not only increasing the fluidity of the magenta toner, but also not inhibiting the chargeability of the magenta toner is an important factor.

Accordingly, the surface of the titanium oxide fine powder or the aluminum oxide fine powder is preferably subjected to a hydrophobic treatment, whereby 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. , It is possible to improve the environmental characteristics of the magenta toner. 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 be uniformly charged by the magenta toner.

In the present invention, in particular, titanium oxide fine powder or alumina fine powder having an average primary particle diameter of 0.01 to 2 μm has good fluidity and uniform charge of the negatively charged magenta toner. This is preferable because fogging hardly occurs. Furthermore, it is hard to be embedded on the surface of the magenta color toner particles, so that toner deterioration hardly occurs,
Multi-sheet durability 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 0.01 μm,
The treated fine powder is easily embedded on the surface of the magenta color toner particles, and the toner is apt to deteriorate quickly, and the durability is easily lowered. This tendency is more remarkable when applied to a sharp melt color toner.

If it exceeds 2 μm, the fluidity is reduced and the charging of the magenta toner tends to be non-uniform, and as a result, toner scattering, fogging and the like are likely to occur, making it difficult to generate a high quality toner image.

In the magenta toner of the present invention, the amount of the titanium oxide fine powder or the aluminum oxide fine powder is preferably 0.5 to 5.0% by weight, more preferably 0.7 to 5.0% by weight.
To 3.0% by weight, more preferably 1.0 to 2.5% by weight. The magenta toner which satisfies the above range has good fluidity, can maintain a stable charge amount, and hardly causes toner scattering.

When the magenta toner of the present invention is used as a two-component developer, the carrier to be used may be, for example, a magnetic material such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, or the like, which is not oxidized or surface oxidized. Metals, their magnetic alloys, their magnetic oxides and their magnetic ferrites can be used.

When the carrier is a carrier in which a carrier core is coated with a coating material, a method for coating the surface of the carrier core with a resin is to dissolve or suspend a coating material such as a resin in a solvent and apply the solution. Either a method of attaching to a carrier core or a method of simply mixing with a powder can be applied.

Examples of the coating material for the carrier core include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of ditersharry butylsalicylic acid, styrene resin, acrylic resin, It is appropriate to use one or more of polyamide, polyvinyl butyral, and amino acrylate resin, but it is not necessarily limited thereto.

The treatment amount of the above-mentioned 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 average particle size of the carrier is 10 to 100 μm,
It preferably has a thickness of 20 to 70 μm.

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 in an amount of 0.01 to 5% by weight. , Preferably 0.1-1% by weight coated
A coated magnetic ferrite carrier having the above average particle size in which carrier particles of 0 mesh pass / 400 mesh on is 70% by weight or more is exemplified.

When the coated magnetic ferrite carrier has a sharp particle size distribution, favorable triboelectric charging properties can be obtained with respect to the magenta toner of the present invention, and the effect of improving electrophotographic properties can be obtained.

When a two-component developer is prepared by mixing with the magenta toner in the present invention, 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 concentration is less than 2% by weight, the image density tends to be low.
If it exceeds 5% by weight, fogging and scattering in the machine tend to occur, and the useful life of the developer tends to be shortened.

Next, the magenta 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 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 to be a color image. 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.

[0094] The printer unit includes a photosensitive drum 1 for forming an image.
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 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 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.

In the above image forming step, 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 toner images of 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, 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).

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 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.

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 (where N is a factor of N / 10 KOH)

Method for Measuring Friction Charge of Toner FIG. 2 is an explanatory view of an apparatus for measuring the friction 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, the suction device 51 (measurement container 5)
The part in contact with 2 is at least an insulator), and the pressure of the vacuum gauge 55 is adjusted to 250 mmAq by adjusting the air volume control valve 56 by suctioning through the suction port 57. 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 set to V (volt). 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 ) (However, measurement conditions are 23 ° C. and 60% RH.)

The carrier used for the measurement is a carrier particle of 250-mesh pass / 350 mesh-on in a range of 70-90.
A coated ferrite carrier with weight percent is used.

The fine particles of titanium oxide fine particles and alumina fine particles
Measurement method of uniform particle diameter The primary particle diameter was measured by observing titanium oxide fine particles and alumina fine particles with a transmission electron microscope, and measuring 300 particle diameters of 0.005 μm or more in a visual field of 30,000 to 50,000 times. Obtain the average particle diameter by using a scanning electron microscope and observe 300 particles of titanium oxide and alumina particles, which are magnified 30,000 to 50,000 times in the visual field, by XM.
A is qualitative and the average particle diameter is determined by measuring the particle diameter.

[0113]

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

Example 1 Polyester Resin No. 1 100 parts by weight (condensed polymer of propoxylated bisphenol A and fumaric acid, acid value: 10.8 mgKOH / g)-Negative charge control agent 4 parts by weight (aluminum compound of di-tert-butylsalicylic acid)-The following compound ( III) 5 parts by weight

[0115]

Embedded image

The above materials are sufficiently premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely 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 material was strictly and simultaneously removed with a multi-division classifier to obtain magenta color toner particles having a weight average diameter of 8.0 μm.

On the other hand, hydrophilic titanium oxide fine powder (primary average particle size 0.02 μm) was used as a fluidity improver and a charge stabilizer.
m, BET specific surface area 140 m ² / g) 100 parts by weight of nC ₄ H ₉ —Si (OCH ₃ ) ₃ and 20 parts by weight of the surface treatment, primary average particle diameter 0.02 μm, hydrophobicity A hydrophobic titanium oxide fine powder A having a chemical degree of 70% was obtained.

100 parts by weight of magenta color toner particles and 1.5 parts by weight of hydrophobic titanium oxide fine powder A were mixed to prepare magenta toner 1 having hydrophobic titanium oxide fine particles on the surface of magenta color toner particles.

Magnetic ferrite carrier particles (surface having an average particle size of 3) coated with the magenta toner 1 and a silicone resin.
0 μm) to obtain a two-component magenta developer.

The above two-component magenta developer was supplied to 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 -25 mC / kg.

After the end 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.

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. That is, as the gloss value is higher, the image surface is determined to have a smoother, more glossy color quality with high gloss, and when the gloss value is lower, it is determined that the image surface is less dull and less saturated. In Example 1, the gloss at a contrast potential of 300 V was 2
1%.

For measuring the 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 target chromaticity of the obtained image was obtained. That is, a ^* = 75.2b ^* =-2.3 L ^* =
46.3.

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. At that time, the image density was fixed at 1.70,
a ^* , b ^* (a ^* , b ^* are chromaticities indicating hue and saturation), L
^* (Lightness) was 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 °.

Further, the color image formed on the transparency film is transferred to an overhead projector (O).
HP), the transparency of the OHP image projected was also good.

The transparency of the OHP image in the above examples was evaluated based on the following evaluation criteria by projecting a color image formed on a transparency film using a commercially available overhead projector.

(Evaluation Criteria) ：: Excellent in transparency, no unevenness in brightness and darkness, and excellent in color reproducibility. (Good) Δ: There is slight unevenness in brightness, but there is no practical problem. (Possible) ×: There is uneven brightness and poor color reproducibility. (Not possible)

The obtained solid image (image density of 1.7) was obtained.
When the light fastness of (0) was confirmed substantially according to JIS K7102, the image after light irradiation for 400 hours showed almost the same image density (1.68) as the initial stage, and almost no change in hue was observed (ΔE = 2.8). Note that a carbon arc lamp was used as a light source.

The hue change was quantitatively evaluated by determining the ΔE value of the following equation.

[0134]

(Equation 2)

Example 2 The compound (I) used in Example 1
Instead of II), the following formula (IV)

[0136]

Embedded image Magenta toner 2 was prepared in the same manner as in Example 1 except that the compound (IV) represented by the following formula was used.

Evaluation was made in the same manner as in Example 1. As a result, good image stability and charging stability were exhibited in both a high temperature and high humidity environment and a low temperature and low humidity environment. A ^* = 73 b ^* = 0
L ^* = 46.0 and although slightly reddish,
An image of the target color tone was obtained.

<Comparative Example 1> Compound (I) used in Example 1
In place of II), C.I. I. Pigment Red 5
A magenta toner 3 was prepared in the same manner as in Example 1 except that 7: 1 was used.

Evaluation was made in the same manner as in Example 1. As a result, the initial charge amount in a high-temperature, high-humidity environment was low, which is presumed to be due to addition of water to Ca ions contained in the used pigment. .

A ^* = 74 b ^* = 2 L ^* = 45.
0, as compared with Example 1, having a strong reddish tint and poor light fastness.

Example 3 The polyester resin No. used in Example 1 was used. In place of polyester resin No. 1, 2
Magenta Toner 4 was obtained in the same manner as in Example 1 except that (condensation polymer of propoxylated bisphenol A and fumaric acid, acid value: 4.0 mgKOH / g). Evaluation was performed in the same manner as in Example 1. As a result, 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 4 The polyester resin No. used in Example 1 was used. In place of polyester resin No. 1, Three
(Condensed polymer of propoxylated bisphenol A and fumaric acid, acid value: 20.2 mgKOH / g) Except for using magenta toner 5 in the same manner as in Example 1.
I got 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 2> The polyester resin No. used in Example 1 was used. In place of polyester resin No. 1 having an acid value of 1.8 mg KOH / g, Except for using 4,
Magenta toner 6 was obtained in the same manner as in Example 1. When evaluated in the same manner as in Example 1, there was no particular problem under the normal temperature and normal humidity environment, but in the durability under the low temperature and low humidity environment,
From around the 10000th sheet, the image density decreased and fogging began to occur slightly.

<Comparative Example 3> The polyester resin No. used in Example 1 was used. In place of polyester resin No. 1 having an acid value of 28 mg KOH / g, Magenta Toner 7 was obtained in the same manner as in Example 1 except that No. 5 was used. Example 1
When evaluated in the same manner as above, under normal temperature and normal humidity environment, the initial image density was high, and the durability of a large number of sheets was good, but under a high temperature and high humidity environment, the charge amount of the magenta toner gradually decreased, As a result, the image density increased, and scattering and fogging began to occur slightly.

<Comparative Example 4> The polyester resin No. used in Example 1 was used. In place of styrene-n-butyl acrylate copolymer No. 1 6 (Mw: 30,000, Mn: 900
Magenta toner 8 was prepared in the same manner as in Example 1 except that (0, acid value: 0 mgKOH / g) was used as the binder resin. When evaluated in the same manner as in Example 1,
Good results were obtained in each environment, but the color mixing with the yellow and cyan toners was inferior to the magenta toner of Example 1. That is, red and blue images with high chroma and lightness could not be obtained.

<Comparative Example 5> Compound (I) used in Example 1
In place of II), C.I. I. Pigment Red 5
A magenta toner 9 was prepared in the same manner as in Example 1 except for using. Evaluation was performed in the same manner as in Example 1. As a result, an image lacking in OHP transparency was obtained due to poor pigment dispersion in the polyester resin.

<Comparative Example 6> Compound (I) used in Example 1
In place of II), C.I. I. Pigment Red 1
A magenta toner 10 was prepared in the same manner as in Example 1 except that 70 was used. Evaluation was made in the same manner as in Example 1. As a result, the charge amount under high temperature and high humidity decreased, and the image density increased accordingly, and scattering and fogging began to occur. A ^* = 73 b ^* = 2 L ^* = 44.
0, and the color tone was also slightly reddish compared to Example 1.

<Example 5> Instead of the hydrophobic titanium oxide fine powder A used in Example 1, hydrophilic alumina fine powder (primary average particle size: 0.02 µm, BET specific surface area: 130 m)
_{^{2 / g) iso-C 4}} H 9 -Si per 100 parts by weight
(OCH ₃ ) _{3 The same} procedure as in Example 1 was carried out except that a fine powder of hydrophobic alumina B having a primary particle diameter of 0.02 μm and a degree of hydrophobicity of 70%, which was surface-treated using 17 parts by weight, was used. Magenta toner 11 was prepared and evaluated in the same manner as in Example 1.

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

Comparative Example 7 Instead of the hydrophobic titanium oxide fine powder A used in Example 1, hydrophilic silica (primary average particle size: 0.007 μm, BET specific surface area: 380 m ² /
g) 2 parts of hexamethyldisilazane per 100 parts by weight
Primary particle diameter 0.007μ surface treated using 0 parts by weight
m, magenta toner 1 in the same manner as in Example 1 except that hydrophobic silica fine powder C having a hydrophobicity of 65% was used.
2 was prepared and evaluated in the same manner as in Example 1. In endurance in a low-temperature and low-humidity environment, the charge amount of the toner starts to increase around the 2,000th sheet, the image density decreases,
The durability was interrupted at the 5000th sheet. In the durability under a high-temperature and high-humidity environment, the charge amount of the toner gradually started to decrease, and toner scattering and fog began to be noticeable.

Example 6 Compound (I) used in Example 1
In place of II), C.I. I. Pigment
A magenta toner 13 was prepared in the same manner as in Example 1 except that Red 31 was used. When evaluated in the same manner as in Example 1, a ^* = 74 b ^* = − 5.0 L
^* = 45.0. Although the color was slightly shifted to blue compared to Example 1, a toner of a practical level was obtained.

[0152]

Embedded image

Example 7 The compound (I) used in Example 1
In place of II), C.I. I. Pigment
A magenta toner 14 was prepared in the same manner as in Example 1 except that Red 184 was used. When evaluated in the same manner as in Example 1, a ^* = 74b ^* = − 0.9
L ^* = 46.0. The toner was slightly reddish compared to Example 1, but a toner of a practical level was obtained.

[0154]

Embedded image

<Example 8> A magenta toner 14 was prepared in the same manner as in Example 1 except that the negative charge control agent used in Example 1 was omitted. Evaluation was performed in the same manner as in Example 1. As a result, a toner of a practical level was obtained, although the charging stability was slightly lower than that of Example 1 and the density fluctuation was large.

Table 1 shows the toner composition of each of Examples and Comparative Examples.
Table 2 shows the evaluation results.

[0157]

[Table 1]

[0158]

[Table 2]

[0159]

The magenta toner of the present invention is prepared by subjecting a specific polyester resin as a binder resin to magenta color toner particles containing a compound (I) which is a β-naphthol derivative as a magenta colorant, and subjecting the particles to hydrophobic treatment. The titanium oxide fine powder or the alumina fine powder having a specific average primary particle size is added externally, so it shows good hue, has excellent color reproducibility, and friction of toner under high temperature and high humidity environment. A reduction in the amount of charge is suppressed, and an excessive increase in the amount of triboelectric charge in a low-temperature and low-humidity environment is suppressed, the image is excellent in environmental stability, and an image having excellent light fastness of a fixed magenta image is formed. Is possible.

[Brief description of the drawings]

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

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

[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 (9)

[Claims] 1. At least a binder resin and a magenta colorant
Having magenta color toner particles containing
In the toner, the binder resin has an acid value of 2 to 25 mgKOH / g.
And a magenta colorant represented by the following formula:
(I)(Where R ₁, R _Two, R _Three, R _FourIs OCH_Three,halogen
Group, H, OH, NO_Two, OC_TwoH_Five, Alkyl group, NH_Two,
N (CH_Three)_Two, NHCOCH_ThreeIndicates one of )so
A magenta color toner particle having an average primary particle diameter of 0.0
1-2 μm hydrophobized titanium oxide fine powder or acid
The magenta toner has a weight average particle diameter of 3 to 15 μm.
Magenta toner. 2. The magenta colorant has the following formula (II):(Where R ₁, R _Two= OCH_Three, R _Three, R _Four= OCH_ThreeIf
Represents Cl. 2. The compound according to claim 1, which is a compound represented by the formula:
Magenta toner. 3. The magenta colorant has the following formula (III): The magenta toner according to claim 1, which is a compound represented by the following formula: 4. The magenta colorant has the following formula (IV): The magenta toner according to claim 1, which is a compound represented by the following formula: 5. The titanium oxide fine powder or aluminum oxide fine powder subjected to the hydrophobic treatment has an average primary particle diameter of 0.0
The thickness is 1 to 0.2 μm.
The magenta toner according to any one of the above. 6. The method according to claim 1, wherein the magenta colorant represented by the formula (I) is contained in an amount of 1 to 15 parts by weight with respect to 100 parts by weight of the binder resin. Magenta toner described in 1 above. 7. The magenta toner according to claim 1, wherein the magenta toner has a negative charging property. 8. The magenta toner according to claim 1, wherein the magenta toner further contains a metal compound of an aromatic carboxylic acid derivative. 9. The magenta toner according to claim 8, wherein the metal compound of the aromatic carboxylic acid derivative is colorless, white or pale.