JPH11102087A - Developer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure stable negative chargeability and to prevent the occurrence of image defects such as fog by mixing three toners each contg. a specified metallic complex salt compd. and a resin binder in a specified weight ratio. SOLUTION: At least two toners selected from the group consisting of a 1st toner contg. a 2:1 type metallic complex salt compd. represented by formula I and a resin binder, a 2nd toner contg. a 2:1 type metallic complex salt compd. represented by formula II and a resin binder and a 3rd toner contg. a 2:1 type metallic complex salt compd. represented by formula III and a resin binder are mixed in a weight ratio of 6:94 to 94:6. In the formula I, X is nitro or halogen, Y is H, halogen or nitro and M is Co. In the formula II, X is -CONHPh, Y is -SO2 C2 H5 , M is Co and A is an alkali metallic or ammonium ion. In the formula III, X is nitro or halogen, Y is H, halogen or nitro and M is Cr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used in an electrophotographic system or an electrostatic recording system.
In particular, the present invention relates to a developer used in a two-component developing method using a mixture of a toner and a carrier.

[0002]

2. Description of the Related Art In an electrophotographic apparatus or an electrostatic recording apparatus, in order to visualize an electrostatic latent image formed on an electrostatic holding member from a photoreceptor or a dielectric, a conventional method has been used.
A two-component developing method using a toner and a carrier and a one-component developing method using a toner also having a carrier function are widely used.

[0003] Such a toner is disclosed in JP-A-5-3134.
As disclosed in Japanese Patent Publication No. 04, generally, a thermoplastic resin, a coloring agent, and other additives such as wax are melt-mixed,
After being uniformly dispersed, the solidified product is pulverized and classified to produce colored fine particles having a desired particle size. Alternatively, a method of adding a polymerization initiator to a synthetic resin monomer, further mixing a colorant, and other additives such as a wax, and suspending the mixture in water to polymerize the mixture to produce colored fine particles having a desired particle size. Can be.

[0004] Since the electrostatic holder can be charged positively or negatively, a positive or negative electrostatic latent image is obtained by exposure under the original. Developing with a positively charged toner on a negative electrostatic latent image produces a positive-positive image consistent with the original. On the other hand, when development is performed on the positive electrostatic latent image with negatively charged toner, a positive-negative image is obtained. Thus, there are two types of electrophotographic toner, positively charged toner and negatively charged toner.

[0005] The coloring material mixed with the toner plays an important role as a charge control agent in terms of its electrostatic properties as well as coloring. In particular, many dyes and pigments conventionally used as colorants are positively charged, and even if they are negatively charged, their chargeability is weak. For this reason, when a conventional negatively charged toner is used, fogging or the like occurs, and it has been difficult to obtain a clear image.

Examples of such negatively chargeable dyes include nigrosine dyes, azine dyes, metal complex salts of monoazo dyes, metal complex salts of salicylic acid, metal complex salts of naphthoic acid, metal complex salts of dicarboxylic acid, and copper phthalocyanine pigment. Can be Above all, metal complex salts of monoazo dyes are widely used for black toners because of their high ability to impart electric charge by triboelectric charging.

For example, Japanese Patent Publication No. 41-6397, Japanese Patent Publication No. 41-12915, and Japanese Patent Publication No. 41-20
No. 153, JP-B-43-27596, JP-B-51-29827, JP-A-47-5637, JP-A-49-21151, and JP-A-49-27.
No. 229 discloses an example in which a negatively charged 2: 1 type metal complex dye is used for a toner.

However, these dyes not only have a low negative charge performance in essence, but also have poor compatibility with a binder resin and are not uniformly dispersed in toner particles, so that practical negative chargeability can be obtained at all. I couldn't.

Conventionally, the composition of the developer has been adjusted by changing its components, for example, a charge control agent, for each model of the image forming apparatus to be used. When the developers having different compositions are mixed with each other, they adversely affect the charging characteristics. Therefore, when the developer is changed along with the improvement or change of the model, the developer excessively produced for the old model is used. Had been discarded.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a stable negative charge even when toners containing different charge control agents are mixed with each other. An object of the present invention is to provide a developer composition which does not cause image defects such as fog.

[0011]

According to the present invention, firstly, the following general formula (1):

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(Wherein X is a nitro group or a halogen atom, Y is a hydrogen atom, a halogen atom or a nitro group, and M is a cobalt atom) and a 2: 1 type metal complex salt compound and a binder resin A first toner containing the following formula (2)

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(Where X represents a —CONHPh group, Y represents a —SO ₂ C ₂ H ₅ group, M represents a cobalt atom, and A represents an alkali metal or ammonium ion). Toner containing a metal complex salt compound and a binder resin, and the following general formula (3)

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(Where X is a nitro group or a halogen atom, Y is a hydrogen atom, a halogen atom, or a nitro group, M is a chromium atom, and A is an alkali metal or ammonium ion). At least two kinds of toners selected from the group consisting of a third toner containing a type 1 metal complex compound and a binder resin are used at 6:94 to 9
Provided is a developer composition characterized by being mixed at a weight ratio of 4: 6.

The present invention secondly provides a first toner containing a 2: 1 type metal complex compound represented by the above general formula (1) and a binder resin, and a second toner represented by the above general formula (2). :
Second containing a type 1 metal complex compound and a binder resin
And the third toner containing the 2: 1 type metal complex compound represented by the general formula (3) and the binder resin were mixed at a weight ratio of 6 to 88: 6 to 88: 6 to 88. A developer composition is provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted intensive studies to obtain good negative chargeability by mixing toners containing different charge control agents, and have accomplished the present invention.

According to the first invention, the following general formula (1)

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(Wherein, X is a nitro group or a halogen atom, Y is a hydrogen atom, a halogen atom or a nitro group, and M is a cobalt atom) and a 2: 1 type metal complex salt compound and a binder resin A first toner containing the following formula (2)

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(Wherein, X represents a -CONHPh group, Y represents a -SO ₂ C ₂ H ₅ group, M represents a cobalt atom, and A represents an alkali metal or ammonium ion). Toner containing a metal complex salt compound and a binder resin, and the following general formula (3)

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Wherein X is a nitro group or a halogen atom, Y is a hydrogen atom, a halogen atom, or a nitro group, M is a chromium atom, and A is an alkali metal or ammonium ion. At least two kinds of toners selected from the group consisting of a third toner containing a type 1 metal complex compound and a binder resin are used at 6:94 to 9
A developer composition is provided which is mixed at a weight ratio of 4: 6.

According to the second aspect of the present invention, all of the above-mentioned first to third toners are 6 to 88: 6 to 88: 6 to 88.
Is provided in a weight ratio of

The above general formula (1) or the above general formula (2)
The dye consisting of the 2: 1 type metal complex compound represented by
The negative charge of itself is extremely large. Compared with known dyes, it has good compatibility with binder resins, and therefore, is uniformly dispersed in toner fine particles and exhibits good negative charging performance. Further, when toner fine particles containing these dyes are mixed at a predetermined ratio, better negative charging performance can be obtained. Further, even if a toner containing a dye composed of a 2: 1 type metal complex compound represented by the general formula (3) is mixed, good negative charging performance is exhibited.

The developer of the present invention gives a charge amount suitable for developing an electrostatic image by friction with a carrier or the like, and is used in an environment in which fluctuations in frictional charging greatly affect, such as high temperature, high humidity, and low temperature, low humidity. However, even when the development is repeated, the charge amount is kept constant, and the charge amount distribution is kept uniform and constant. Therefore, an image using this toner has a uniform and constant density, and it is possible to obtain a clear image that is environmentally stable over a long period of time as compared with a conventional negatively charged developer. Becomes

The first to third toners are each
Contains fine silica particles, and the content of the fine silica particles is the largest in the first toner, then the largest in the third toner, and is equal to that in the second toner in the second toner. Or less than that. Thereby, the fluidity becomes better and a developer having a stable negative charging property can be obtained.

Further, the silica fine particles used in the first toner have a primary particle diameter of 12 nm or less, are hydrophobicized by hexamethylsilazane, and the silica fine particles used in the second toner are larger than 12 nm. It has a primary particle size, is made hydrophobic by dimethyldichlorosilane,
It is preferable that the silica fine particles used in the toner have a primary particle diameter of greater than 16 nm and are hydrophobicized with dimethyldichlorosilane. As a result, a developer having better environmental stability and fluidity and having stable negative chargeability can be obtained.

Further, the average diameter of the first toner is smaller than the average diameter of the second toner, and the average diameter of the second toner is equal to or smaller than the average diameter of the third toner.
It is preferable that the average diameter of the toner is larger than the average diameter of the first toner. As a result, rapid mixing when the first to third toners are mixed is performed, and a developer having a stable negative charging property is obtained.

The first to third toners are prepared by adding the dye represented by the general formula (1), (2) or (3) to the binder resin in a weight ratio of 0.1 to 5%. Parts, and can be produced by a melt-kneading / crushing / classifying method.

If the amount is less than 0.1 part by weight, the effect of controlling the charge when added is not sufficiently obtained. If the amount is more than 5 parts by weight, excess dye bleeds and the charge tends to increase or decrease. , Tend to be unstable.

Further, the amount of the dye added to the first to third toners does not necessarily have to be the same,
A suitable amount is selected and added within the range of the heavy material part.

The developer of the present invention has the following general formula (4): (MO) _x (Fe ₂ O ₃ ) _Y (4) (where M is Li, Mg, Mn, Fe (II) ), C
o, one or two or more metals selected from the group consisting of Ni, Cu, Zn, Cd, Sr, and Ba, and the molar ratio X / Y between X and Y is 1.0 or less. It is preferable to further include a carrier to be used.

By using these carriers,
The property of the developer being electrostatically negatively charged is further improved.

The carrier particles preferably used in the present invention are of a ferrite type and have a Fe ₂ O ₃ content of at least 40 mol%.
Is preferable. (MO) _X is, for example, NiO, CuO, MgO, ZnO, MnCO ₃ , Ba
CO ₃ , SrCO ₃ , Li ₂ (CO ₃ ), CdO and the like can be mentioned.

In addition, SiO ₂ , CaCO ₃ , TiO ₂ , SnO ₂ , Pb may be added to the carrier particles as additives.
O, V ₂ O ₅ , Bi ₂ O ₃ , Al ₂ O _{3 and the} like can be used.

The surface of the carrier is preferably coated with a resin composition comprising a silicone resin.

As the silicone resin, a silicone resin having a low surface tension is preferable, and a resin whose substituent is a methyl group, a phenyl group or an ethyl group is preferable. Further, as the modified silicone resin, for example, alkyd modified,
Modified silicone resins such as epoxy-modified, acrylic-modified, polyester-modified, phenol-modified, melanin-modified, and urethane-modified can be used.

Since the silicone-coated carrier has sufficient durability and stable triboelectricity, it is possible to obtain a developer with little environmental dependency and a long service life.

Further, other colorants,
Alternatively, carbon black or the like may be added.

Furthermore, inorganic oxide fine particles can be further added to the developer of the present invention.

Examples of such inorganic oxide fine particles include silica fine particles such as silicon dioxide, aluminum silicate, sodium silicate, zinc silicate and magnesium silicate, zinc oxide, titanium oxide, aluminum oxide, zirconium oxide and titanium oxide. Strontium acid, barium titanate and the like. In addition, resin fine powder such as polymethyl methacrylate, polyvinylidene fluoride, and polytetrafluoroethylene may be used as a cleaning aid. These external additives may have been subjected to a surface treatment such as hydrophobicity.

Further, as other known charge control agents,
For example, the metal chelate of alkyl salicylic acid, chlorinated polyester, polyester having an excess acid group, chlorinated polyolefin, metal salt of fatty acid, fatty acid soap, etc. can be prepared by converting the above general formula (1), general formula (2) or general formula (3). Can be used in combination so as not to affect the charge control agent of the compound represented by

Further, as the binder resin used in the present invention, a copolymer of styrene and its substitute, an acrylic resin and a methacrylic resin which can be used as a binder resin for a developer can be used.

Examples of the above-mentioned copolymers of styrene and substituted styrene include polystyrene homopolymer, hydrogenated styrene resin, styrene-isobutylene copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene-styrene terpolymer. Polymer, acrylonitrile-styrene-acrylate terpolymer, styrene-
Acrylonitrile copolymer, acrylonitrile-acrylic rubber-styrene terpolymer, acrylonitrile-chlorinated polystyrene-styrene terpolymer, acrylonitrile-EVA-styrene terpolymer, styrene-p
-Chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene rubber, styrene-maleic acid ester copolymer, styrene-isobutylene copolymer, styrene-maleic anhydride copolymer, and the like.

As the acrylic resin, for example,
Polyacrylate, polymethyl methacrylate, polyethyl methacrylate, poly-n-butyl methacrylate, polyglycidyl methacrylate, polyfluorinated acrylate, styrene-methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-ethyl acrylate copolymer And the like.

In addition, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, phenol resin, urea resin, polyvinyl butyral, polyacrylic resin, rosin, modified rosin, terpene resin, fatty acid or Alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be used alone or as a mixture.

Examples of the coloring agent usable in the present invention include carbon black and organic or inorganic pigments and dyes. Although there are no special restrictions, carbon black includes acetylene black, furnace black, thermal black, channel black, Ketjen black, and the like, and face dyes such as First Yellow G, Benzidine Yellow, Indofast Orange,
Irgazine Red, Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Lisor Red 2
G, lake C, rhodamine FB, rhodamine B lake, phthalocyanine blue, pigment blue, brilliant green B, phthalocyanine green, quinacridone and the like can be used alone or in combination.

Wax can be used for the toner particles used in the present invention. As such a wax, a paraffin having 8 or more carbon atoms, a polyolefin or the like is preferable. For example, low molecular weight polypropylene, low molecular weight polyethylene, liquid paraffin, acid amide, stearic acid wax, montan wax, sasol wax, caster wax, Chlorinated paraffins and the like are preferred. The wax may be mixed and dispersed in advance during the production of the binder resin.

The developer of the present invention can be applied to the following developing devices.

FIG. 1 is a diagram showing an example of a developing device to which the developer of the present invention can be applied.

In FIG. 1, an electrostatic charge image is formed on the photosensitive drum 1. A toner container 2 near the photosensitive drum 1 contains a toner and a carrier (developer) 3.
A multi-pole magnet roll 4 and a developing sleeve 5 mounted on the outer periphery of the multi-pole magnet roll 4 are provided on the photosensitive drum 1 side.
The carrier of the developer 3 adheres to the surface of the developing sleeve 5 by the magnetic force of the multi-pole magnet roller 4, and the toner particles adhere to the surface of the carrier to form a toner layer. still,
The toner / carrier concentration ratio of developer 3 was 6.0%.
In FIG. 1, the multipolar magnet roller is fixed, the developing sleeve is rotated counterclockwise, and the developer 3 is conveyed as needed.
The transport amount of the developer 3 is regulated by the regulating blade 6. At the same time, the photosensitive drum 1 is rotated clockwise, and a bias is applied from the power source 7 at a position where the developing sleeve 5 and the photosensitive drum 1 approach each other, so that the electrostatic attraction causes the developing sleeve 5 to move onto the photosensitive drum 1. The toner 3 adheres to the electrostatic image, and development is performed.

[0050]

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

Example 1 Styrene-acrylic copolymer resin 89% by weight Carbon black 7% by weight Polypropylene 2% by weight The following structural formula (5)

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The above components were mixed, melt-kneaded, finely ground and classified to obtain toner particles having an average particle size of 9.0 μm. The toner particles 10
0% by weight of hexamethyldisilazane treated with an average diameter of 1
0.5% by weight of 2 nm hydrophobic silica and 0.
1 wt% was mixed to obtain a first toner.

Further, among the above components, the metal-containing complex dye represented by the structural formula (5) is converted to the following structural formula (6)

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Toner particles having an average particle size of 10.0 μm were obtained in the same manner except that the metal-containing complex dye represented by the formula (1) was used. Hydrophobic silica having an average diameter of 14 nm treated with dimethyldichlorosilane was added to 100% by weight of the toner particles.
3 parts by weight and 0.1% by weight of alumina fine particles are mixed to form a second
Toner.

With respect to 94% by weight of a carrier in which a ferrite core having an average particle diameter of 43 to 100 μm is coated with a silicone resin, 6 of the above-mentioned first toner particles and second toner particles are:
94 mixture of 6% by weight was mixed to prepare an electrophotographic developer composition.

Table 1 shows the amounts of silica, the average diameter, and the mixing ratio of the first toner and the second toner in the developer.

The ferrite core was obtained by pulverizing and mixing 14 mol% of CuO, 16 mol% of ZnO, and 70 mol% of Fe ₂ O ₃ in a wet ball mill for 10 hours, followed by drying.
It was kept at 50 ° C. for 4 hours. This is a wet ball mill 24
It was ground for 5 hours or less. The slurry was granulated, dried, and kept at 1140 ° C. for 6 hours, and then pulverized and classified to have an average particle size of 43 to 100 μm. The composition of this carrier was 14 mol% of CuO, 15 mol% of ZnO, Fe ₂ O ₃
At 71 mol%, X / Y was 0.45. The silicone resin was coated on the carrier in a fluidized bed using a fluidized bed, and baked at 190 ° C. for 3 hours to obtain a resin-coated carrier.

Commercial copying machine (ED-6550, manufactured by Toshiba)
, The above-mentioned developer is put into the container, and a copy test is performed.
%, The charge amount, the image density and the developer toner specific density were measured. Tables 2 to 4 show the obtained results. As shown in Tables 2 to 4, a high-density clear image was obtained even in each environment. Even during a continuous copying test, the toner specific concentration in the developer was maintained at a stable level, and a further 120,000 sheets ( Even after a copying test under environmental conditions of 60,000 sheets at low temperature, low humidity and high temperature and high humidity), a clear image could be maintained at a high density without a change in charge amount.

Examples 2 to 9 First, second, and third toners were respectively prepared under the conditions shown in Table 1 below, and a mixture of the toners mixed at a predetermined mixing ratio was mixed with the same resin as in Example 1. A developer composition was prepared by mixing using a coat carrier.

The third toner has the following structural formula (7)

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The average particle diameter was 10.5 μm in the same manner as in the first toner except that the metal-containing complex dye represented by
Was obtained. Hydrophobic silica having an average diameter of 14 nm, which was treated with dimethyldichlorosilane in 100% by weight of the toner particles, was mixed in an amount shown in Table 1 below with alumina fine particles of 0.1%.
1 wt% was obtained by mixing.

A copy test was performed on each of the obtained developer compositions in the same manner as in Example 1 and the results were measured. As shown in Tables 2 to 4, a clear image of high density was obtained in each environment. The toner density in the developer is kept stable during the continuous copying test, and the charge amount can be maintained even after the copying test of 120,000 sheets (60,000 sheets at low temperature, low humidity and high temperature and high humidity). There is no change, and a clear image with high density can be maintained.

Comparative Examples 1 to 3 First, second, and third toners were prepared under the conditions shown in Table 1, and a mixture of the toners mixed at a predetermined mixing ratio was used in the same ferrite core as in Example 1. A styrene-methyl methacrylate resin having a monomer composition ratio of styrene and methyl methacrylate of 45:55 using a fluidized bed,
The resin was coated and baked in the same manner as in Example 1, and mixed using the obtained resin-coated carrier to prepare an electrophotographic developer composition.

When a copy test was conducted in the same manner as in Example 1, as shown in the test results in Tables 2 to 4, a clear image with high density was obtained at the initial stage. The specific density and the amount of charge were remarkably changed. Particularly, environmental conditions were remarkable at low temperature, low humidity and high temperature and high humidity, and a clear image could not be maintained at a high density.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

According to the present invention, it is possible to obtain a developer composition which has stable negative chargeability and does not cause image defects such as fog even when toners containing different specific charge control agents are mixed with each other. Can be Further, even if the developer composition is changed in accordance with the change of the image forming apparatus, the original developer can be effectively used without being discarded.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a developing device for applying a method of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C09B 45/14 G03G 9/08 375 9/10 311 321

Claims (6)

[Claims] [Claim 1] The following general formula (1) (Wherein, X represents a nitro group or a halogen atom, Y represents a hydrogen atom, a halogen atom or a nitro group, and M represents a cobalt atom) and contains a 2: 1 type metal complex salt compound and a binder resin. First toner, represented by the following general formula (2): (Where X is a —CONHPh group, Y is —SO ₂ C ₂
A second toner containing a 2: 1 type metal complex salt compound represented by an H ₅ group, M represents a cobalt atom, and A represents an alkali metal or ammonium ion) and a binder resin; ) (Wherein, X is a nitro group or a halogen atom, Y is a hydrogen atom, a halogen atom, or a nitro group, M is a chromium atom, and A represents an alkali metal or ammonium ion). A developer composition comprising a mixture of at least two toners selected from the group consisting of a third toner containing a complex salt compound and a binder resin in a weight ratio of 6:94 to 94: 6. 2. The following general formula (1): (Wherein, X represents a nitro group or a halogen atom, Y represents a hydrogen atom, a halogen atom or a nitro group, and M represents a cobalt atom) and contains a 2: 1 type metal complex salt compound and a binder resin. First toner, represented by the following general formula (2): (Where X is a —CONHPh group, Y is —SO ₂ C ₂
A second toner containing a 2: 1 type metal complex salt compound represented by an H ₅ group, M represents a cobalt atom, and A represents an alkali metal or ammonium ion) and a binder resin; ) (Wherein, X is a nitro group or a halogen atom, Y is a hydrogen atom, a halogen atom, or a nitro group, M is a chromium atom, and A represents an alkali metal or ammonium ion). The third toner containing the complex salt compound and the binder resin is prepared in the range of 6 to 88: 6 to 88: 6.
A developer composition characterized by being mixed at a weight ratio of from -88. 3. The first to third toners, respectively,
Contains fine silica particles, and the content of the fine silica particles is the largest in the first toner, then the largest in the third toner, and in the second toner, is equal to or greater than that in the second toner. The developer composition according to claim 1, wherein the content is not more than the above. 4. The silica fine particles used in the first toner have a primary particle diameter of 12 nm or less, are hydrophobicized by hexamethylsilazane, and the silica fine particles used in the second toner are 12 nm. The silica fine particles having a larger primary particle diameter, which has been hydrophobized by dimethyldichlorosilane, and which is used for the third toner, has a particle size of 16 nm.
The developer composition according to any one of claims 1 to 3, which has a larger primary particle diameter and is hydrophobized with dimethyldichlorosilane. 5. An image forming apparatus according to claim 1, wherein the first toner has an average diameter of the second toner.
The average diameter of the second toner is equal to or smaller than the average diameter of the third toner, and the average diameter of the third toner is smaller than the average diameter of the first toner. 5 is also large.
The developer composition according to any one of the above. 6. The following general formula (4): (MO) _x (Fe ₂ O ₃ ) _Y (4) (where M is Li, Mg, Mn, Fe (II), C
o, one or two or more metals selected from the group consisting of Ni, Cu, Zn, Cd, Sr, and Ba, and the molar ratio X / Y between X and Y is 1.0 or less. The developer composition according to any one of claims 1 to 5, further comprising a carrier to be used.