JP2000314986A - Electrostatic image developer and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic image developer capable of forming good image quality and not only maintaining this image quality for a long period but also forming always good developed images even in fluctuating environments from low temperature and low humidity to high temperature and high humidity. SOLUTION: The electrostatic image developer comprises colored thermoplastic resin substantially spherical grains, fine particles firmly fixed to the surfaces of these colored resin grains, and ultrafine particles deposited on the surfaces of the resin grains including the fine fixed particles, and capable of freely moving on their surfaces. These fixed particles are at least one kind of mixture of (1) a metal oxide compound and (2) fine organic particles having a molecular weight of 200-5,000, or organic fine particles having a complex structure or fine resin particles having a functional group equivalent of <=1500.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrostatic image developer and a method for producing the same.

[0002]

2. Description of the Related Art Generally, development of an electrostatic latent image is performed by adhering colored powder (electrostatic image developer... Toner) to an electrostatic image (electrostatic latent image) formed on a photoconductor. This electrostatic image developer is usually produced by dispersing a pigment or a dye in a thermoplastic resin and then pulverizing to a desired particle size.
For example, fine particles called a charge control agent are kneaded in a thermoplastic resin together with additives such as a pigment (colorant) and wax, and then pulverized and classified to produce and prepare a developer.

Incidentally, the surface structure of the electrostatic image developer (toner particles) affects the fluidity and charging characteristics of the developer, and further has a large effect on the image quality of a developed image. Various attempts have been made to control properties. That is, since the surface structure of the particulate developer is determined by the existing state of the toner components such as the pigment on the surface, the addition amount and the dispersion process are controlled by changing. Further, after the toner is prepared, oxide fine particles such as colloidal silica powder and resin fine particles are added and adhered to the surface thereof. Here, the fine particles to be added and adhered to the particulate developer surface are usually called external additives, and play an important role in improving the image quality and maintaining the image quality of the developer.

[0004]

In recent years, with the increase in the definition of a copied image, the charge rises rapidly, and a developer having a small particle size is used. Is required. Further, with the colorization of copied images, it is important to improve and secure the reliability of the developer in terms of charging characteristics, fixability, durability and the like of each color as compared with the conventional black developer.

However, in the conventional electrostatic image developer, the amount of surface exposure of the charge control agent varies depending on the dispersion state and the pulverization process, and it has been difficult to obtain a stable chargeability. In addition, free charge control agent particles generated in the pulverizing step and the like contaminate the surface of the carrier particles, adversely affect the charging characteristics of the developer, and cause problems such as fogging of a developed image.

More specifically, referring to the problems in the conventional electrostatic image developer, for example, in the case of a color toner, in order to maintain the color balance, the charge amounts of the toners of the respective colors are adjusted so as to be substantially the same. There is a need. However, since the charging characteristics differ depending on the pigment, it is difficult to ensure the same charge amount.

[0007] In the development of an electrostatic image, if a background fouling phenomenon (fogging) in which toner adheres to a so-called white background portion (non-image portion) occurs, the image quality is greatly reduced. here,
The fog is caused by the presence of oppositely charged toner particles, and as described above, an attempt has been made to improve it by adding a charge control agent or the like, but no satisfactory solution has been found.

[0008] By repeating the developing operation, the surface condition of the toner (developer) particles changes, and the charging characteristics also change with the change of the surface conditions. Therefore, it is difficult to maintain the initial image characteristics.

[0009] The transfer efficiency when transferring the developed image to plain paper is important from the viewpoint of effective use of the developer, but is actually attached as a transfer residual toner on the surface of the photoreceptor. Then, the transfer residual toner is removed by a scraper when the photoconductor is reused. Here, if the amount of the transfer residual toner is large, the deterioration of the photoconductor is accelerated, and contamination in the copying apparatus is caused.

In the case where the toner (developer) particles are reduced in size to increase the definition of a developed image, it is difficult to ensure the fluidity of the toner.

As a result of intensive studies on the solution of the above problem, the present inventor has found that the problem can be solved if the particle structure of the electrostatic image developer (toner) is set as follows. Was. That is, an electrostatic image toner for visualizing an image by attaching it to an electrostatic image has substantially spherical colored thermoplastic resin particles as nuclei (nuclear particles). Metal compound particles and (2) molecular weight 200-50
At least one of organic fine particles having a salt structure or organic fine particles having a complex structure, and resin fine particles having a functional group equivalent of 1500 or less.
The mixture particles with the seeds (fixed fine particles) are fixed,
It has been found that most of the above problems can be solved by adopting a structure in which fine particles (externally added ultrafine particles) which can freely move on the surface of the core particles including the fixed fine particles are adhered.

The present invention has been made on the basis of the above findings, and provides not only good development image quality and maintenance of good development image quality for a long time, but also environmental change from low temperature and low humidity to high temperature and high humidity. Also, an object of the present invention is to provide an electrostatic image developer capable of always forming a good developed image and a method of manufacturing the same.

[0013]

According to the present invention, a substantially spherical colored thermoplastic resin particle, fixed fine particles fixed on the surface of the colored thermoplastic resin particle, and a colored thermoplastic resin containing the fixed particle are provided. An electrostatic image developer having ultrafine particles attached to the particle surface and capable of freely moving on the surface, wherein the fixed particles are (1) metal compound particles, (2) a salt structure having a molecular weight of 200 to 5,000. An electrostatic image developer comprising a mixture of at least one of organic fine particles, organic fine particles having a complex structure, and resin fine particles having a functional group equivalent of 1500 or less.

According to a second aspect of the present invention, in the electrostatic image developer according to the first aspect, the surface of the metal compound particles in the fixed fine particles is subjected to a hydrophobic treatment.

According to a third aspect of the present invention, in the electrostatic image developer according to the first or second aspect, the metal compound particles in the fixed fine particles are metal oxide particles, metal sulfide particles, metal fluoride particles, and metal. It is characterized by being at least one kind of carbide particles.

According to a fourth aspect of the present invention, there is provided the electrostatic image developer according to any one of the first to third aspects, wherein the ultrafine particles adhered have a particle size of 10 to 300 nm and a specific surface area measured by a BET method. It is characterized by having a surface of 5 to 300 m ² and a hydrophobic treatment.

The invention of claim 5 is characterized in that, per 100 parts by weight of substantially spherical colored thermoplastic resin particles, (1) metal compound particles, and (2) organic fine particles of a salt structure or an organic material of a complex structure having a molecular weight of 200 to 5,000. Fine particles, 0.05 to 3 parts by weight of fixing fine particles, which is a mixture with at least one of resin fine particles having a functional group equivalent of 1500 or less, are added, and the high-speed mixing is performed to fix the fine particles on the surface of the colored thermoplastic resin particles. And a method for producing an electrostatic image developer.

In the invention of claims 1 to 4, the substantially spherical colored thermoplastic resin particles (core particles) have an average particle size of 5 to 5.
It has a sphericity α of 0.8 or more.
Here, the sphericity α is defined as a value obtained by dividing the shortest diameter of the core particle by the longest diameter. Then, the core particles are made into a sphere while smoothing the surface by using a rolling operation in a process of kneading, pulverizing and classifying a thermoplastic resin, a pigment and other additives by heating the thermoplastic resin, (b) ) Normally crushed and classified particles are re-mechanically tumbled to make them spherical, (c) Normally crushed and classified particles are passed through a hot air stream to make them spherical, (d) thermoplastic resin is generated Polymerizing suspended particles containing monomers, pigments and other additives, (e) atomizing a hot melt of colored thermoplastic resin particles or an organic solvent diluent, drying, cooling, and solidifying, etc. It can be formed by means.

Here, thermoplastic resin (binder component)
Examples thereof include a polyethylene resin, a polyester resin, a polystyrene resin, an epoxy resin, a styrene / acrylic copolymer resin, and a polycarbonate resin, and these may be used alone or as a mixture of two or more.
Examples of the colorant (pigment) dispersed in the thermoplastic resin include carbon black, phthalocyanine blue, azo lake pigment, and quinacridone pigment.

In the inventions of claims 1 to 4, (1) the metal compound particles, which constitute one of the components of the fixed fine particles fixed to the surface of the spherical colored thermoplastic resin particles (core particles), are a metal which is stable at room temperature. Oxide, fluoride, sulfide, carbide, and nitride particles are included. Specifically, for example, silicon oxide, titanium oxide, aluminum oxide, iron oxide, zinc oxide, zirconium oxide, calcium fluoride, silicon carbide, tantalum-hydride, aluminum nitride, silicon nitride, and the like can be given.

On the other hand, the other component of the fixed fine particles (2)
High-concentration functional group organic fine particles having a molecular weight of 200 to 5000 and having a salt structure (for example, nigrosine and calixarene), or organic fine particles having a complex structure (for example, a metal complex of t-butylsalicylic acid and a metal-containing azo dye) having a functional group equivalent of 1500 or less (For example, resins containing a sulfone group, a carboxyl group, an amino group, an ammonium group, etc. in the molecule).

The mixing ratio of (1) metal compound particles to (2) high concentration organic fine particles having a salt structure having a molecular weight of 200 to 5,000 is generally 0.03 to 3% by weight of the metal compound particles, About 0.1 to 3% by weight of fine particles. In addition, the particle diameter of the fixed fine particles of these mixed systems is generally
It is about 10 nm or more and about 2000 nm or less, and is about 0.03 to 5 parts by weight, preferably 0.05 to 3 parts by weight, per 100 parts by weight of the spherical colored thermoplastic resin particles (core particles). Further, the fixation of the fixed particles of the mixed system is carried out on a relatively smooth spherical colored thermoplastic resin particle (core particle) surface with a height of 10 to 300 nm.
It is desirable that they protrude to the extent.

The fixed fine particles can be easily fixed to the spherical colored thermoplastic resin particle surface by a high-speed tumbling and mixing system using, for example, a high speed mixer, an impact mill or a pin mill. . That is, the surface of the spherical colored thermoplastic resin particles is softened and smoothed by the heat generated at the time of high-speed rolling, and the fixed fine particles are easily embedded and fixed on the surface. As another means,
A method in which the spherical colored thermoplastic resin particles are dispersed and deposited and polymerized while mixing the vinyl monomer and the fixed particles, or while the spherical colored thermoplastic resin particles are melted in a hot air flow, Spraying to cool and solidify.

The ultrafine particles (externally added ultrafine particles) attached to the surface of the colored thermoplastic resin particles containing the fixed fine particles and capable of freely moving on the surface according to the invention of the first to fourth aspects,
It is at least one oxide particle selected from aluminum oxide, a silicon oxide element, zinc oxide, titanium oxide, zirconium oxide, and iron oxide. And the particle size is 10nm ~
About 300nm, BET method specific surface area is 5 ~ 300m
² / g is desirable, and the amount of adhesion is spherical,
Colored thermoplastic resin particles that adhere fixed particles to the surface
0.05 to 10 parts by weight per 100 parts by weight, preferably
0.1 to 5 parts by weight.

The attachment of the externally added fine particles to the surface of the colored thermoplastic resin particles containing the fixed fine particles can be performed simultaneously with the step of fixing the fixed fine particles to the surface of the colored thermoplastic resin particles. However, most of the externally added fine particles need to be adhered to such an extent that the surface can freely move (non-fixed). That is, when the externally added fine particles are fixedly present, the developed image (visible image) is liable to cause background fog (fogging), and the fluidity of the developer is also reduced. Furthermore, when the development is repeated, the image density tends to decrease, and the occurrence of fog tends to be promoted.

In order to improve the moisture resistance and fluidity of the metal compound particles and a part of the externally added fine particles, which are part of the above-mentioned fixed particle components, it is preferable to perform a surface treatment with a silicone compound. That is, it is desirable that the silicone compound is previously adsorbed or bonded to the surfaces of the metal compound particles and the externally added fine particles of the fixed particle component. Here, as the desirable silicone compound, a general formula:
(R _x ) _n Si (Y _x ) _m , or [(R _y ) ₂ -Si-O-]
_a linear or cyclic silicone compound represented by _l ,
And a polymer containing the same as a unit.

Where n and m are integers of 1 to 3, and l is 3
An integer of ~ 10, R _x is a methyl group, an alkyl group, an allyl group,
Any of a fluorinated alkyl group and a fluorinated alkyl allyl group, R _y is hydrogen or a methyl group, Y _x is an alkoxy group, a chloro group, a hydroxyl group, an alkyl group, or an amino group, an ammonium group, an epoxy group, A compound in which a halogen group, a hydroxyl group or hydrogen is bonded.

Generally, as the silicone compound,
(a) silicone oil which is a polymer having dimethyldichlorosilane as a unit, (b) trimethyltrichlorosilane,
Hexamethyldisilazane, trimethyldichlorosilane and dimethyldichlorosilane polycondensed in the presence of water, and (c) various silane coupling agents. In the inventions according to claims 1 to 4, a sufficient amount of functional group-containing organic particles for controlling electric charge is applied to the surface of the substantially spherical colored thermoplastic resin particles which are relatively smoothed by applying mechanical or thermal energy. Can stably maintain the existing state of the organic particles having a functional group on the surface. Therefore, while the charging characteristics are extremely stabilized, the influence on the charging characteristics due to additives such as pigments added to the colored thermoplastic resin particles can be significantly reduced.

That is, since a constant charge amount can be obtained without being influenced by the pigment to be used, excellent development image quality can be obtained by color development which requires that development characteristics do not change due to coloring. In addition, the externally added fine particles that can be freely moved provide good fluidity, while preventing changes in the surface state due to storage of the developer and frictional wear. That is, the handleability of the developer is greatly improved, and not only a high-quality developed image is obtained, but also there is no possibility that image deterioration is caused by repeated development, and good transfer efficiency is exhibited.

According to the fifth aspect of the present invention, by applying the high-speed mixing method, the fixing fine particles can be embedded and fixed on the substantially spherical colored thermoplastic resin particles (core particles) without causing spherical damage. The above electrostatic image developer can be easily obtained.

[0031]

Embodiments of the present invention will be described below.

Example 1 After 100 parts by weight of a polyester resin, 3 parts by weight of a phthalocyanine blue pigment and 2 parts by weight of a polyethylene wax were mixed, the mixture was further hot-kneaded with a twin-screw mixer, pulverized and classified to obtain an average particle size of 8 μm. Of substantially spherical colored thermoplastic resin particles (core particles).

To 100 parts by weight of the spherical colored thermoplastic resin particles, 0.5 part by weight of a t-butylsalicylate zinc complex (fixed fine particles) having an average particle diameter of 0.1 to 2.0 μm and an average particle diameter of 200 μm
0.5 part by weight of spherical titanium oxide particles having a particle diameter of m 2 was added to a hybridizer, and mixed at a peripheral speed of 40 m for 10 minutes. By this mixing treatment, particles were obtained in which the t-butylsalicylate zinc complex fine particles and the spherical titanium oxide particles were exposed on the surface of the spherical colored thermoplastic resin particles, and were dispersed and fixed as a whole.

Next, 100 parts by weight of the particles having the fixed fine particles fixed on the surface were added with a specific surface area of 150 m ² /
g (average primary particle size: 15 μm), 1 part by weight of ultrafine particles of a silicon oxide element treated with silicone oil was added to a high-speed mixer and mixed at a peripheral speed of 20 m for 30 seconds to prepare a cyan toner.

The cross section of the cyan toner particles prepared above was
Observed with M, the t-butylsalicylate zinc complex fine particles and titanium oxide particles are dispersedly embedded and fixed on the surface of the spherical colored thermoplastic resin particles.
It was confirmed that the ultrafine particles of the silicon oxide element were attached to the surface of the spherical colored thermoplastic resin particles containing the t-butylsalicylate zinc complex fine particles in a freely movable state.

The particle size of the cyan toner is 40 parts by weight.
μm ferrite particles (19 parts by weight) were added and mixed, and the charge amount of the developer (particles) was measured by a blow-off method.
μC / g. Also, the charge amount of this developer is
Even when the preparation time was increased, the amount of change was within the range of ± 2 μC / g, and stable charging characteristics were exhibited regardless of the mixing operation.

Next, the cyan toner was filled in a developing device prepared in advance, that is, a one-component developing type LBP developing cartridge provided with an aluminum developing roll, and a negatively charged electrostatic latent image was developed. . In this development process, a uniform toner layer was formed on the development roll surface, and a positive image having an extremely low fog level was obtained.

Further, the development and transfer of the same original image (5% solid density) were repeated for 10,000 sheets, and the toner consumption per A4 sheet attached to the transferred image was measured. Consumption was almost unchanged (30 ± 5 mg) and stable development was performed. Moreover, the density and fog level of the developed image were hardly changed as compared with the initial image.

Example 2 In the case of Example 1, the phthalocyanine blue pigment 3
Magentant was prepared under the same conditions except that 4 parts by weight of dimethylquinacridone pigment was used instead of parts by weight. Observation of the cross section of this magenta toner by TEM revealed that the magenta toner had the same structure as that of Example 1.
When the charge amount was measured in the same manner as in Example 1, it was -20
μC / g.

Example 3 In the case of Example 1, the phthalocyanine blue pigment
A black toner was prepared under the same conditions except that 3 parts by weight of carbon black was used instead of 3 parts by weight. Observation of the cross section of this black toner with a TEM revealed that it had the same structure as in Example 1, and the charge amount was measured in the same manner as in Example 1 to be -19 μC / g. Was.

Example 4 In the case of Example 1, the phthalocyanine blue pigment
A yellow toner was prepared under the same conditions except that 3 parts by weight of benzidine yellow was used instead of 3 parts by weight.
Observation of the cross section of this yellow toner with a TEM revealed that the yellow toner had the same structure as in Example 1. The charge amount was measured in the same manner as in Example 1, and was found to be -20 μC / g.

In each of Examples 2 to 4, even if the mixing and preparation time of the developer was changed, the amount of change in the charge amount was ±
It was confirmed that the toner had a stable charge amount within the range of 2 μC / g.

Using the developers of Examples 2 to 4 above, Example 1
When the development was carried out under the same conditions as in the above case, a uniform developer layer was formed on the surface of the developing roll, and a positive image having an extremely low fog level was obtained. Furthermore, the same original image (5% solid density) was repeatedly developed and transferred to 10,000 sheets, and the toner consumption per A4 sheet attached to the transferred image was measured. The development was stable with little change (30 ± 5 mg). Moreover, the density and fog level of the developed image
Little change was observed compared to the initial image.

When each of the toners of Examples 1 to 4 was used in a cleaning-less developing device to develop an electrostatic image, the transfer efficiency was high in each case. A high quality developed image with little change compared to the image was obtained.

Further, each of the toners of Examples 1 to 4 was
When the transferred image was fixed at a low temperature without blocking even in an environment of 50 ° C., no toner offset development occurred, and good thermal fixing characteristics were exhibited.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, as the thermoplastic resin forming the binder component, other thermoplastic resins other than the polyester resin, as the fixing fine particles, other metal complexes of salicylic acid other than the t-butylsalicylate zinc complex, and as the externally added fine particles, Similar effects can be obtained even with titanium oxide fine particles other than silicon oxide fine particles.

Example 5 After 100 parts by weight of styrene acrylic resin, 5 parts by weight of carbon black (pigment) and 102 parts by weight of polyethylene wax were mixed, the mixture was further kneaded with a twin-screw mixer, pulverized, classified and averaged. Substantially spherical colored thermoplastic resin particles (core particles) having a particle size of 8 μm were obtained.

The above spherical colored thermoplastic resin particles are heated at 400 ° C.
While softening in a hot air stream of the above, spraying the t-butylsalicylate zinc complex and the spherical silicon oxide particles, the fixed particles of the mixed system are exposed on the surface of the spherical colored thermoplastic resin particles,
In addition, particles dispersed and fixed as a whole were obtained. The composition ratio here is 0.5 parts by weight of a t-butylsalicylate zinc complex (fixed fine particles) having an average particle diameter of 0.1 to 2.0 μm and an average particle diameter of 300 μm per 100 parts by weight of the spherical colored thermoplastic resin particles.
0.5 parts by weight of the spherical silicon oxide element particles.

Next, particles obtained by fixing the above-mentioned fixed particles on the surface
100 parts by weight, the specific surface area measured by the BET method is 100 m ² / g
Ultrafine particles of silicon oxide element treated with silicone oil 1
Parts by weight and 0.5 parts by weight of spherical ultrafine titanium oxide particles treated with silicone oil having a specific surface area of 50 m ² / g were added to a high-speed mixer and mixed at a peripheral speed of 20 m for 30 seconds to prepare a black toner. .

When the cross section of the black toner particles prepared above was observed by TEM, it was found that the t-butylsalicylate zinc complex fine particles and the titanium oxide particles were dispersedly embedded and fixed on the surface of the spherical colored thermoplastic resin particles. And that
It was confirmed that ultrafine particles of the silicon oxide element and titanium oxide adhered to the surface of the spherical colored thermoplastic resin particles containing the t-butylsalicylate zinc complex fine particles and the spherical silicon oxide element particles in a freely movable state.

A particle diameter of 40 μm per 1 part by weight of the black toner
19 parts by weight of ferrite particles were mixed with a point, and the charge amount of the developer (particles) was measured by a blow-off method.
g. Further, the charge amount of the developer was within the range of ± 2 μC / g even when the mixing / preparation time was increased, and exhibited a stable charge characteristic regardless of the mixing operation.
Next, the above-described black toner was filled in a developing device prepared in advance, that is, a one-component developing type LBP developing cartridge having an aluminum developing roll, and a negatively charged electrostatic latent image was developed. In this developing treatment, a uniform developer layer was formed on the surface of the developing roll, and a positive image having an extremely low fog level was obtained.

Further, development and transfer were repeated 10,000 times for the same original image (5% solid density), and the toner consumption per A4 sheet attached to the transferred image was measured. Consumption was almost unchanged (30 ± 5 mg) and stable development was performed. Moreover, the density and fog level of the developed image were hardly changed as compared with the initial image.

Example 6 In the case of Example 1, spherical colored thermoplastic resin particles were mixed with 100 parts by weight of a low molecular weight polyethylene resin (melting point 100 ° C.) and 3 parts by weight of phthalocyanine blue (pigment) with a hot roll. Thereafter, the mixture was blown into a spray dryer in a molten state, cooled and solidified to obtain substantially spherical colored thermoplastic resin particles (core particles) having an average particle size of 8 μm. The same conditions as in Example 1 were used except that the colored thermoplastic resin particles were used as core particles, to obtain a cyan toner having a stable charge amount of -25 μC / g. When the electrostatic latent image was developed using this cyan toner in the same manner as in Example 1, a clear and high-quality developed image was obtained.

Further, even after the toner was stored for 50 hours while being opened at 50 ° C., no occurrence of a blocking phenomenon was observed, and good fluidity was maintained. Further, even when the developed image was transferred onto plain paper and fixed without supplying silicone oil to the fixing heating roll, toner offset development did not occur and it was confirmed that oilless fixing was possible.

[0055]

According to the first to fourth aspects of the present invention, there is provided a developer exhibiting a constant charge amount without being influenced by a coloring agent (pigment). That is, since the development characteristics are not changed by the coloring agent, excellent development image quality can be obtained by color development. In addition, good fluidity is imparted, changes in the surface state due to its preservation and frictional wear are avoided, handling properties are greatly improved, and good transfer efficiency is exhibited.
High quality images can always be obtained easily even in repeated development.

According to the fourth aspect of the present invention, the electrostatic image developer can be easily obtained efficiently and in mass production.

[0057]

Claims (5)

[Claims] 1. A substantially spherical colored thermoplastic resin particle,
Fixed electrostatic particles adhered to the surface of the colored thermoplastic resin particles, and an electrostatic image developer having ultrafine particles attached to the surface of the colored thermoplastic resin particles including the fixed fine particles and capable of freely moving on the surface, The fixed particles are (1) metal compound particles, (2) molecular weight 2
An electrostatic image developer comprising a mixture of at least one of organic fine particles having a salt structure or organic fine particles having a complex structure of from 00 to 5,000, and resin fine particles having a functional group equivalent of 1500 or less. 2. The electrostatic image developer according to claim 1, wherein the surface of the metal compound particles in the fixed fine particles is subjected to a hydrophobic treatment. 3. The metal compound particles in the fixed fine particles are at least one of metal oxide particles, metal sulfide particles, metal fluoride particles, and metal carbide particles. Electrostatic image developer. 4. The ultrafine particles to be attached have a particle size of 10 to 300 nm,
Measured by a specific surface area of 5 to 300 m ^2, and surface electrostatic image developer of claims 1 to 3 any one, wherein that the hydrophobized with BET method. 5. A substantially spherical colored thermoplastic resin particle 1.
Per 100 parts by weight, (1) metal compound particles, (2) molecular weight 200
Addition of 0.05 to 3 parts by weight of fixing fine particles, which is a mixture with at least one of organic fine particles of a salt structure or organic fine particles of a complex structure, and resin fine particles having a functional group equivalent of 1500 or less, followed by high-speed mixing and coloring heat A method for producing an electrostatic image developer, comprising a step of fixing the fine particles on the surface of a plastic resin particle.