JPH0719074B2 - Development resin composition for developing electrostatic image - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition for a developer for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Conventional technology and problems]

Conventional electrophotographic methods include US Pat. Nos. 2,297,691 and 235.
No. 7809, etc., the photoconductive insulating layer is uniformly charged, then the layer is exposed to light to dissipate the charge on the exposed portion, thereby causing an electrical latent image. An image is formed, and then the latent image is visualized by adhering fine powder having a colored charge called a toner (developing process), and the obtained visible image is transferred onto a transfer material such as transfer paper. After transferring (transfer process), permanently fix by heating, pressure or other suitable fixing method (fixing process)
Consists of steps.

In this way, toner is not only used in the development process, but also in the transfer process,
It must have the functions required in each step of the fixing step.

Generally, toner undergoes mechanical frictional force due to shearing force and impact force during mechanical operation in the developing device, and deteriorates during copying of several thousand to tens of thousands of sheets. To prevent such toner deterioration, a tough resin with a large molecular weight that can withstand mechanical friction may be used, but these resins generally have a high softening point and are non-contact fixing methods such as oven fixing and infrared fixing. Due to the poor thermal efficiency in the radiant fixing, the fixing is not performed sufficiently, and the thermal efficiency is good in the contact fixing method, so even in the widely used heat roller fixing method, the temperature of the heat roller is sufficient for sufficient fixing. It is necessary to increase the temperature, which not only causes the deterioration of the fixing device, curling of the paper, and the increase of energy consumption, but also when such a resin is used, the manufacturing efficiency is remarkably reduced when the toner is pulverized and manufactured. To do. Therefore, a binder resin (adhesive resin) having a too high degree of polymerization and a softening point cannot be used. On the other hand, in the heat roller fixing method, the surface of the heating roller and the toner image surface of the sheet to be fixed come into pressure contact with each other, so that the thermal efficiency is remarkably good and it is widely used from low speed to high speed. In doing so, the so-called offset phenomenon, in which toner adheres to the surface of the heating roller and is transferred to the subsequent transfer paper or the like, is likely to occur. In order to prevent this phenomenon, the surface of the heating roller is processed with a material with excellent mold release properties such as fluorine resin, but a release agent such as silicone oil is applied to the surface of the heating roller to completely prevent the offset phenomenon. is doing.

However, the method of applying silicone oil is
Not only is the fixing device increased in size and cost, but also complicated, which is likely to cause troubles and is not preferable.

Also, as described in JP-B-55-6895 and JP-A-56-98202, there is a method of improving the offset phenomenon by widening the molecular weight distribution width of the binder resin, but the polymerization degree of the resin becomes high and fixing The temperature also needs to be raised.

Further improved methods include JP-B-57-493 and JP-A-50-50.
As described in JP-A-44836 and JP-A-57-37353, there is a method of improving the offset phenomenon by making the resin asymmetric and cross-linked, but the fixing property is not improved.

Generally, the minimum fixing temperature is between the cold offset temperature and the hot offset temperature, so the usable temperature range is between the minimum fixing temperature and the hot offset temperature. The fixing temperature can be lowered by increasing the offset temperature as much as possible, and the usable temperature range can be widened, and energy saving, high-speed fixing, and curling of paper can be prevented. In addition, since double-sided copying can be performed without trouble, there are advantages that the copying machine is made intelligent, the temperature control accuracy of the fixing device is improved, and the allowable range is relaxed.

Therefore, there is always a demand for resins and toners having good fixability and offset resistance.

Generally, a polyester resin and a styrene resin are often used as the developer resin, and it is economically desirable to use the styrene resin. However, the styrene resin has essentially a high minimum fixing temperature, There was a natural limit to the composition and improvement by adding waxes.

[Means for solving problems]

The present invention has been made to solve these problems and meet the requirements, and the purpose thereof is to prevent offsetting in a heat roller fixing method without applying an offsetting prevention liquid, and at a lower fixing temperature. To provide a developer that can be fixed.

Another object of the present invention is to provide a developer which prevents offset in the heat roller fixing system without adding an offset inhibitor and can fix at a lower fixing temperature.

Another object of the present invention is to provide a developer having good fluidity, causing no blocking and having a long life (hard to deteriorate).

Another object of the present invention is to provide a developer resin having good kneadability and pulverizability during the production of the developer.

The present inventors have arrived at the present invention as a result of earnest research to achieve the above object.

That is, the present invention provides a resin composition for a developer, which comprises 80.00 to 99.95% by weight of a binder resin and 0.05 to 20.00% by weight of liquid polybutadiene, and the liquid polybutadiene is uniformly dispersed in the binder resin. It is a thing.

The binder resin used in the present invention is (a) styrene and / or
Or styrene derivative 20.00-100.00 parts by weight (b)
It is a copolymer with at least one kind of (meth) acrylic acid or its ester in an amount of 80.00 to 0 parts by weight.

If necessary, the resin composition for a developer according to the present invention may be used in combination with other binder as the main component of the binder resin, and the binder resin and the colorant are mainly used. A dry developer composition for electrophotography for heat-pressing and fixing as a component can be obtained. The liquid polybutadiene according to the present invention is a polymer of butadiene, which shows fluidity at least at -10 ° C or higher, and is 0.
It is a copolymer of 05 to 30.00% by weight of acrylonitrile.

Examples of the above-mentioned (a) styrene or styrene derivative in the present invention include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p -Methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4
-Dichlorostyrene and the like can be mentioned.

Examples of the acrylic acid or ester thereof (b) include acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate,
Tert-butyl acrylate, amyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methoxyethyl acrylate, acrylate 2 -Hydroxyethyl, 3-hydroxypropyl acrylate, glycidyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate and the like can be mentioned. Examples of the methacrylic acid-based monomer include methacrylic acid. Acid, Methyl Methacrylate, Ethyl Methacrylate, n-Propyl Methacrylate, Isopropyl Methacrylate, n-Butyl Methacrylate, Isobutyl Methacrylate, tert-Butyl Methacrylate, Amyl Methacrylate, Silicate Methacrylate Lohexyl, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, methacryl Examples thereof include glycidyl acid ester, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like.

A preferred liquid polybutadiene for use in the present invention is commercially available from Ube Industries, Ltd. (manufactured by BF Guddleitch Co., USA) under the trade name of Hycar.

The grades and a few properties of these liquid polybutadienes useful in the present invention are shown in Table 1 below.

Among the components constituting the developer resin according to the present invention, (a) styrene or styrene derivative of styrene resin used as a binder resin forms a main skeleton of the resin,
(B) (Meth) acrylic acid or its ester adjusts the thermal characteristics such as the softening point of the resin, determines the charge, and adjusts the charge amount, while the liquid polybutadiene lowers the minimum fixing temperature and improves offset resistance. It is presumed that it will be a component. Acrylonitrile is copolymerized in the liquid polybutadiene, and it is considered that the nitrile group contributes to the dispersibility in the binder resin main component and also to the offset resistance improvement. However, if the content of the nitrile group exceeds 30% by weight in the liquid polybutadiene, satisfactory offset resistance cannot be obtained. From this point of view, the liquid polybutadiene according to the present invention has an acrylonitrile unit content of 0.05 to 30% by weight in the copolymer.
Further, if the content of liquid polybutadiene in the developer resin composition of the present invention is less than 0.05% by weight, the fixability cannot be improved, and if it exceeds 20% by weight, the glass transition point of the binder resin is lowered. And the storage stability as a toner decreases.

Further, the developer resin composition of the present invention, from the viewpoint of physical properties,
The high temperature type flow tester has a softening point of preferably 100 to 160 ° C. If it is out of the range and is too low, the offset resistance is insufficient, and if it is out of the range and too high, the fixing property is insufficient. .

The binder resin according to the present invention is produced by a well-known addition polymerization reaction, whereas the liquid polybutadiene used in the resin composition of the present invention is added at the initial stage of polymerization during the production of the binder resin. Then, the liquid polybutadiene is uniformly dispersed in the binder resin by carrying out a polymerization reaction, or by dissolving and dispersing it in a common solvent together with the binder resin after polymerization, and distilling off the solvent. The thing is obtained.

In producing an electrophotographic developer using the resin composition of the present invention, a colorant and other additives are added to the resin by a conventional method, and as the colorant used at that time,
Carbon Black, Acetylene Black, Phthalocyanine Blue, Permanent Brown FG, Brilliant Farst Scarlett, Pigment Green B, Rhodamine-B Base, Solpentreed 49, Solpentreed 14
6, Solpent Blue 35 and the like and mixtures thereof can be mentioned, and usually about 1 to 15 parts by weight is used with respect to 100 parts by weight of the resin composition.

When the resin composition according to the present invention is used to prepare a magnetic toner, examples of the magnetic substance include an alloy or compound containing an element exhibiting ferromagnetism such as ferrite and magnetite, and the magnetic substance has an average particle diameter of 0.1 to It is possible to disperse an amount of 40 to 70% by weight in a resin in the form of a fine powder of 1 μm and use it.

Known property improvers contained in the toner include a charge control agent, an anti-offset agent, a fluidizing agent, and the like, but the resin composition of the present invention has good properties by itself, and therefore, toner preparation At times, the addition of these property improving agents becomes unnecessary, or even in the case of adding, a small amount may be sufficient.

As described above, the developer resin composition according to the present invention is prepared by adding liquid polybutadiene at the initial stage of polymerization during the production of the binder resin to cause a polymerization reaction, or by dissolving it in a common solvent together with the binder resin after polymerization. The liquid polybutadiene is uniformly dispersed in the binder resin by dispersing the solvent, and the solvent is distilled off.
For example, by mixing carbon black and kneading it to obtain a toner, it is possible to obtain a toner having excellent image fixability and offset resistance, and good storage stability as a toner. On the other hand, in the case of the toner obtained by mixing the binder resin, the liquid polybutadiene and the colorant at the same time into a toner,
As shown in the reference example, the image fixability, anti-offset property, and storability as a toner were far inferior.

〔Example〕

The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The composition ratios shown in the examples are all expressed in parts by weight.

Example 1 500 parts of xylene and 80 parts of liquid polybutadiene (HYCAR CTBN 1300 × 15) were charged into a reactor equipped with a stirrer, a nitrogen introduction tube, a thermometer, a reflux condenser and a dropping funnel, and the temperature was raised to 80 ° C. Adjust. 810 parts of styrene under nitrogen stream,
A mixed solution of 110 parts of n-butyl acrylate and 5 parts of benzoyl peroxide is added dropwise for 4 hours for polymerization. After aging at the same temperature for 10 hours after the completion of dropping, gradually raise the temperature to 200 ° C.
The pressure was reduced to 0 mmHg, xylene was distilled off, the molten resin was taken out into a stainless steel butt, allowed to cool and crushed,
Powder resin (Koka type flow tester, softening point 129.5 ℃, Tg
62.5 ° C) was obtained. This softening point was measured by using a Koka type flow tester (manufactured by Shimadzu Corporation) and heating a sample of 1 cm ³ at a heating rate of 6
While heating at ℃ / min, a load of 20 kg / cm ² is applied by the plunger, and a nozzle with a diameter of 1 mm and a length of 1 mm is pushed out, thereby drawing the plunger drop-temperature curve of the flow tester, and the S-shaped curve When the height of the curve is h, the temperature corresponding to h / 2 is the softening point.

93 parts of the resin and 7 parts of carbon black (Regal 400R, manufactured by KYABOT CORPORATION) were mixed in a ball mill, kneaded using a hot roll, cooled, coarsely pulverized with a hammer mill, further finely pulverized with a jet mill, and averaged after classification. A toner having a particle size of 13.6μ was obtained. The toner thus obtained was mixed with carrier iron powder (manufactured by Nippon Iron & Powder Co .; EFV200-300), and the charge amount was measured by a blow-off measuring device to find -18 μc / g.

91 g of the toner was used as carrier iron powder (manufactured by Nippon Iron & Powder Co .; EFV200-
300) 1209g to prepare a developer, and a commercially available electrophotographic copying machine (amorphous asselen for the photoconductor, the diameter of the fixing roller is 60mm, the rotation speed is 255mm / sec, and the temperature of the heat roller in the fixing device is variable. , The oil coating device was removed), a clear image without background stains, bleeding, and black solid portions was obtained.

Further, when the fixing temperature and the offset property of the image were evaluated by controlling the fixing temperature at 140 ° C to 220 ° C, the image was sufficiently fixed at 150 ° C and the offset did not occur. When images were printed up to 50,000 sheets, background fogging and black solid portions were not observed, and clear images were obtained.

What is the minimum fixing temperature here? Put a load of 500 g on a sand eraser with a bottom of 15 mm × 7.5 mm, rub 5 times over the image fixed through the fixing machine, and before and after rubbing with a Macbeth reflection densitometer. The optical reflection density is measured, and it means the temperature of the fixing roller when the fixing rate exceeds 70% as defined below.

Example 2 Styrene 810 in 500 parts xylene as in Example 1.
Part, a styrene-acrylic copolymer obtained by polymerizing a vinyl-based polymer composition solution of 110 parts of n-butyl acrylate with 5 parts of benzoyl peroxide, and liquid polybutadiene (HYCAR
The liquid polybutadiene was uniformly dispersed in the styrene-acrylic copolymer by dissolving CTBN 1300 × 8) in a ratio of 90:10 in xylene, which is a common solvent, and distilling off the solvent. A resin (Koka type flow tester softening point 127.6 ° C, Tg 60.4 ° C) was obtained.

93 parts of the resin and 7 parts of carbon black (Regal 400R manufactured by KYABOT CORPORATION) were mixed in a ball mill, kneaded, pulverized and classified to obtain a toner having an average particle diameter of 14.5 microns. The obtained toner had a charge amount of −20 μc / g.

91 g of the toner was used as carrier iron powder (manufactured by Nippon Iron & Powder Co .; EFV200-
300) 1209 g was mixed to prepare a developer, and an image was formed using the same evaluation machine as in Example 1. As a result, a clear image without background stains, bleeding, and black solid portions was obtained. The fixing temperature of the fixing device was controlled to 140 ° C to 220 ° C, and the fixing property and offset property of the image were evaluated.
No offset has occurred. When images were printed up to 20,000 sheets, background fogging and black solid areas were not observed, and clear images were obtained.

Example 3 The reactor of Example 1 was charged with 500 parts of xylene and 50 parts of liquid polybutadiene (HYCAR CTBN 1300 × 13), and the temperature was adjusted to 8
Adjust to 0 ° C. Styrene 600 parts, 2-ethylhexyl acrylate 180 parts, methyl methacrylate 165 under nitrogen stream
, 5 parts of 3-hydroxypropyl acrylate and 5 parts of lauroyl peroxide are added dropwise and polymerized for 4 hours.
After completion of the dropping, after aging at the same temperature for 10 hours, the pressure was reduced to 60 mmHg while gradually raising the temperature to 200 ° C., xylene was distilled off, the molten resin was reprecipitated in methanol, and after filtration,
Powder resin (Koka type flow tester, softening point 130.9 ℃, Tg6
4.3 ° C) was obtained.

93 parts of the resin and 7 parts of carbon black (Regal 400R manufactured by KYABOT CORPORATION) were mixed in a ball mill, and then kneaded and pulverized.
By classification, a toner having an average particle size of 13.5 microns was obtained. The obtained toner had a charge amount of −18 μc / g.

91 g of the toner was used as carrier iron powder (manufactured by Nippon Iron & Powder Co .; EFV200-
300) 1209 g was mixed to prepare a developer, and an image was formed using the same evaluation machine as in Example 1. As a result, a clear image without background stains, bleeding, and black solid portions was obtained. The fixing temperature of the fixing device was controlled at 140 ° C to 220 ° C, and the fixing property and offset property of the image were evaluated.
No offset has occurred. When images were printed up to 50,000 sheets, clear images were obtained without any background fog or black solid areas being observed.

Example 4 The reactor of Example 1 is charged with 500 parts of xylene and 150 parts of liquid polybutadiene (HYCAR CTBNX 1300 × 9), and the temperature is adjusted to 80 ° C. A mixture of 770 parts of styrene, 50 parts of 2-ethylhexyl acrylate, 5 parts of 2-hydroxyethyl methacrylate, 25 parts of dimethylaminoethyl methacrylate and 10 parts of α, α′-azobisisobutyronitrile under a nitrogen stream. Is polymerized dropwise over 4 hours. After dropping, 10
After aging for the same temperature at the same temperature, the temperature was gradually raised to 200 ° C, the pressure was reduced to 60 mmHg, the xylene was distilled off, the molten resin was taken out into a stainless steel butt, and allowed to cool and pulverized to obtain a powdered resin ( Formula Flow Tester Softening point 126.4 ℃, Tg
57.4 ° C.) was obtained.

93 parts of the resin and 7 parts of carbon black (Regal 400R manufactured by KYABOT CORPORATION) were mixed in a ball mill, and then kneaded and pulverized.
By classification, a toner having an average particle size of 12.5 microns was obtained. The obtained toner had a charge amount of +19 μc / g.

91 g of the toner was used as carrier iron powder (manufactured by Nippon Iron & Powder Co .; EFV200-
300) 1209 g to prepare a developer, and a commercially available electrophotographic copying machine (photoreceptor is organic photoconductor, rotation speed of roller is
When the image was output with the heat roller temperature in the fixing device variable at 255 mm / sec and the oil application device was removed), a clear image with no background stains, bleeding, or black solid areas was obtained. Was obtained. The fixing temperature of the fixing device is 140 ℃ to 2
When the fixing property and the offset property of the image were evaluated by controlling at 20 ° C, the image was fixed at 150 ° C and the offset did not occur. When images were printed up to 30,000 sheets, background fogging and black solid areas were not observed, and clear images were obtained.

Comparative Example 1 Using the reactor of Example 1, a mixed solution of 830 parts of styrene, 170 parts of 2-ethylhexyl acrylate and 15 parts of benzoyl peroxide was added dropwise to 500 parts of xylene at 80 ° C. over 4 hours, and then,
It was aged at the same temperature for 10 hours. After that, toluene was distilled off by the method of Example 1, and the mixture was extracted and pulverized to obtain a powdery resin (Koka type flow tester softening point: 130.5 ° C, Tg: 62.0 ° C). Using the resin, a toner (charge amount was −18 μc / g) was prepared by the same operation as in Example 1, a developer was prepared, and an image was produced using the same evaluation machine as in Example 1. A clear image with no background stains, bleeding, and black solid areas was obtained. When the fixing temperature of the fixing device was controlled at 140 ° C to 220 ° C and the fixing property and offset property of the image were evaluated,
It was fixed at 175 ° C, but offset occurred at all temperatures from 140 to 220 ° C.

Comparative Example 2 Using the reactor of Example 1, a mixed solution of 850 parts of styrene, 140 parts of n-butyl acrylate, 15 parts of divinylbenzene and 15 parts of lauroyl peroxide was added to 500 parts of xylene at 80 ° C. for 4 hours. After dripping and aging at the same temperature for 10 hours, xylene was distilled off by the method of Example 1 and extracted and pulverized to obtain a powdery resin (Koka type flow tester softening point 131.0 ° C, Tg 62.2 ° C). It was
Using the resin, a toner (charge amount was -18.5 μc / g) was prepared by the same operation as in Example 1 to prepare a developer, and an image was produced using the same evaluation machine as in Example 1. A clear image was obtained without scumming, bleeding, and black solid portions. The fixing temperature of the fixing device was controlled to evaluate the image fixing property and offset property.
The offset did not occur from 0 ° C to 220 ° C, but the fixing temperature was 195 ° C.

Comparative Example 3 The styrene-acrylic copolymer obtained by polymerizing the vinyl-based polymer composition liquid in Example 1 alone and liquid polybutadiene (HYCAR CTBN 1300 × 8) were used at a common weight ratio of 75:25. Dissolved in xylene which is a solvent, by distilling off the solvent styrene-a resin in which liquid polybutadiene is uniformly dispersed in an acrylic copolymer (Koka type flow tester softening point 122.3 ℃, Tg 47.8 ℃ ) Got. Using the resin, a toner (charge amount was −19 μc / g) was prepared by the same operation as in Example 1 to prepare a developer, and an image was produced using the same evaluation machine as in Example 1. By the way
A clear image with no background stains, bleeding, and black solid areas was obtained. The fixing temperature of the fixing device was controlled to evaluate the fixing property and offset property of the image.
Offset did not occur up to ℃ and fixing was carried out at 135 ℃.

However, the storage stability of the toner was poor as shown in Table 2.

Comparative Example 4 The liquid polybutadiene of Example 1 (HYCAR CTBN 1300 × 1
5) 80 parts was replaced with 8 parts of α, ω-polybutadiene glycol containing no acrylonitrile (Nippon Soda Co., Ltd., G-2000, number average molecular weight 2000) and the same procedure as in Example 1 was carried out to soften the Koka type flow tester. A resin having a point of 128.0 ° C and a Tg of 63.5 ° C was obtained. Using the resin, by the same operation as in Example 1,
Toner (charge amount was −19 μc / g) was prepared, a developer was prepared, and an image was formed using the same evaluation machine as in Example 1. As a result, scumming, bleeding, and black solid portion omission occurred. No clear image was obtained. The fixing temperature of the fixing device is 140 ℃ ~ 220
When the fixing property and the offset property of the image were evaluated by controlling the temperature to 90 ° C., no offset occurred, but the fixing temperature was 190 ° C.

Reference Example 1 86 parts of a styrene-acrylic copolymer obtained by homopolymerizing the vinyl-based polymerization composition liquid in Example 1, 7 parts of liquid polybutadiene (HYCAR CTBN 1300 × 15) and carbon black (manufactured by KYABOT CORPORATION, Using 7 parts of Legal 400R, the same operation as in Example 1 was performed to obtain toner (charge amount: −18).
μc / g) was used to prepare a developer, and the evaluation was performed using the same evaluation machine as in Example 1. As a result, in the printing durability test, the film was formed on the photoconductor at the stage of 5000 copies. It was generated, the charge amount was also reduced to -9 μc / g, and scumming was observed. Hot offset occurred from 180 ° C., the storage stability of the toner was poor as shown in Table 2, and the performance was inferior to that in which liquid polybutadiene was added during resin production.

However, the storage stability test was performed by the method shown below. Put 200g of toner in polybin, leave it in the atmosphere of 55 ℃ for 3 days, then turn the polybin upside down and the toner will come out immediately.
Or, check if there is no lump even if it comes out, and if there is lump, evaluate whether it can be easily crushed by pushing with a finger.If the toner does not stick out and if the lump does not easily crush with a finger x It was evaluated as Δ when it could be easily crushed with a finger, and evaluated as ○ when there was no lump.

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Claims (1)

[Claims] (A) Styrene and / or styrene derivative (20.0-100.00 parts by weight) and (b) at least one kind of (meth) acrylic acid or its ester 0.00-80.00
Binder resin composed of a copolymer composed of 8 parts by weight and 8 parts by weight
9.95% by weight, liquid polybutadiene 0.05 to 20.00% by weight of a liquid polybutadiene consisting of a copolymer of butadiene 70.00 to 99.95 parts by weight and acrylonitrile 0.05 to 30.00 parts by weight, the liquid polybutadiene being polymerized during the production of the binder resin. Liquid polybutadiene is uniformly dispersed in the binder resin by adding it at the initial stage to cause a polymerization reaction, or by dissolving it in a common solvent together with the binder resin after polymerization and dispersing it, and then distilling off the solvent. A resin composition for a developer for developing an electrostatic charge image, characterized by comprising: