JPH0439669A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To effectively clean up th surface of a photosensitive body without damaging it and to obtain electrostatic charge image developing toner stabilized in frictional electricity by incorporating inorganic fine powder in resin particulates. CONSTITUTION:Coloring particulates consisting of binder resin and a coloring agent and composite particulates obtained by incorporating inorganic fine powder in resin particulates are incorporated in the toner. In this constitution, the abrasive property of the composite particulates can be appropriately set up and the reduction of insulating property of the composite particulates can be effectively suppressed. Consequently appropriate abrasive property and effective cleaning property can be displayed without damaging the surface of the photosensitive body, electrostatic attraction to coloring particulates can be improved and the uniformity and stability of frictional electrification of toner can be sharply improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a toner for developing electrostatic images used in electrophotography, electrostatic recording, electrostatic photography, and the like.

[Conventional technology]

In an example of electrophotography, an electrostatic charge image is formed on a photoconductive photoreceptor by charging and exposure, and this electrostatic charge image is developed with a developer containing toner to form a toner image. The image is transferred to a transfer material and fused to form a visible image. On the other hand, toner remaining on the photoreceptor without being transferred to the transfer material is cleaned by a cleaning means such as a blade.

In toners applied to such electrophotographic methods,
High cleaning properties and appropriate polishing properties are required. That is, if the toner has low cleaning properties, image stains occur due to toner remaining on the surface of the photoreceptor without being cleaned.

Furthermore, if the abrasiveness of the toner is too high, damage will occur on the surface of the photoreceptor, toner material will be embedded in the damaged area and appear as dots on the image when the next image is formed.

On the other hand, if the abrasiveness of the toner is too low, toner substances will gradually adhere and accumulate on the surface of the photoreceptor, resulting in a decrease in the electrical characteristics of the photoreceptor.

However, as techniques related to toner cleaning and polishing properties, the following have been proposed so far.

■ Technology of adding and mixing acrylic polymer fine powder with a smaller diameter than the toner powder (Japanese Patent Laid-Open No. 60-18
6851).

(2) A technique of adding and mixing spherical fine particles whose surfaces are treated with a metal such as nickel to toner particles (Japanese Patent Application Laid-open No. 11956/1983).

■ Technology of adding and mixing composite fine powder, which is made by fine inorganic powder fixed to the surface of fine resin powder with a smaller diameter by mechanical impact force, to the binder resin powder (Japanese Patent Laid-Open No. 64-9114
Publication No. 3).

[Problem to be solved by the invention]

However, in the technique (2) above, sufficient abrasiveness cannot be exhibited because the hardness of the acrylic polymer fine powder is low. Therefore, as images are repeatedly formed, the surface of the photoreceptor becomes filmed with toner material, which causes a problem in that the electrical characteristics of the photoreceptor deteriorate early.

On the other hand, in the case of the above toner (■), when increasing the pressing force of the cleaning blade against the surface of the photoreceptor in order to prevent filming of the photoreceptor by the toner substance,
The deformation of the blade becomes large and its durability is significantly reduced.

In addition, if the toner described in (■) above is a one-component toner, the difference in specific gravity between the toner powder and the acrylic polymer fine powder becomes large because the toner contains a magnetic material, and the toner powder contains a fine acrylic polymer powder. Uniform mixing becomes difficult when adding and mixing powder. As a result, the triboelectric charging properties of the toner become unstable, the acrylic polymer fine powder easily scatters from the toner particles and contaminates the inside of the machine, and furthermore, the developing area for transporting the toner to the developing area becomes unstable. There is a problem in that fine acrylic polymer powder adheres to the sleeve, resulting in poor developer conveyance.

In the technique (2) above, the processing material used to treat the surface of the resin particles constituting the spherical fine particles is a metal such as -''/Kel, which has a low volume resistivity of about 10-8 to 105 Ωcm. Therefore, when spherical fine particles are added and mixed with toner particles, it becomes difficult for the spherical fine particles to electrostatically adhere to the toner particles, and as a result, the triboelectric charging properties of the toner become unstable, and the surface of the developing sleeve There is a problem in that the spherical fine particles stick to each other and the transportability of the developer deteriorates.

In the technique (■) above, the inorganic fine powder is fixed only to the surface of the resin fine powder, so the surface hardness of the composite fine powder becomes too high, and the surface of the composite fine powder is extremely uneven.
Excessive abrasiveness causes damage to the surface of the photoreceptor.

Then, the toner substance becomes embedded in the damaged area and cannot be cleaned, so that there is a problem that black spots occur in the image when the next image is formed.

The present invention was made based on the above circumstances, and
The purpose is to provide a toner for developing electrostatic images that can be cleaned well without damaging the surface of a photoreceptor and has stable triboelectric charging properties.

[Means to solve the problem]

In order to achieve the above object, the present inventors have conducted extensive research and found that by incorporating inorganic fine powder into the resin fine particles instead of on the surface of the resin fine particles, the resulting composite fine particles have an appropriate hardness. In addition, the surface insulation of the composite fine particles is maintained at a sufficiently high level, and as a result, the abrasiveness is moderate, allowing for good cleaning without damaging the surface of the photoreceptor, and also reducing frictional electrification of the toner. The present invention was completed based on the discovery that the properties are stable over a long period of time.

Therefore, the toner for developing electrostatic images of the present invention contains at least colored particles made of a binder resin and a colorant, and composite fine particles made of resin fine particles containing m'R1-free powder. It is characterized by

[Effect]

In the present invention, the composite fine particles have a special structure in which inorganic fine powder is present inside the resin fine particles instead of on the surface of the resin fine particles, so that the abrasiveness of the composite fine particles is made appropriate, and the composite fine particles are This effectively prevented the deterioration of insulation properties.

To explain in detail, since inorganic fine powder is contained inside the resin fine particles constituting the composite fine particles, it is preferable that the hardness of the composite fine particles does not become too large or small compared to the case where inorganic fine powder is simply present only on the surface. As a result,
The abrasiveness becomes appropriate, so that the toner material adhering to the surface of the photoreceptor can be satisfactorily polished, and the surface characteristics of the photoreceptor can be stably maintained over a long period of time.

Even when the inorganic fine powder is a low-resistance material, the inorganic fine powder is contained inside the resin fine particles, so that the insulation on the surface of the resin fine particles is maintained at a sufficiently high level. Therefore, when the composite fine particles are added to and mixed with the colored particles, the composite fine particles are sufficiently electrostatically attached to the colored particles, and the composite fine particles are not separated from the colored particles or scattered.

In addition, in the case of a toner for a -component developer, a magnetic substance is contained inside the colored particles, but inorganic fine powder is also contained inside the composite fine particles, and the content is adjusted to obtain appropriate abrasiveness. Since it can be used in a relatively large amount, the difference in specific gravity between the colored particles and the composite fine particles becomes small, and when the composite fine particles are added to the colored particles and mixed, they are mixed sufficiently uniformly. . As a result, the adhesion of the composite fine particles to the colored particles is improved, and the uniformity and stability of the triboelectric charging properties of the toner are significantly improved. Therefore, there is no fear that the composite fine particles will become loose and stick to the developing sleeve or scatter and contaminate the inside of the machine, and it is possible to stably transport the toner to the developing area.

Therefore, according to the toner of the present invention, the surface of the photoreceptor can always be maintained in a good condition with good polishing properties and cleaning properties, and the triboelectric charging properties are uniform and stable for a long period of time. Therefore, high-density, good images can be stably formed many times without image defects such as fog or black spots.

[Specific structure of the invention]

Hereinafter, the configuration of the present invention will be specifically explained.

The composite fine particles constituting the toner of the present invention are composed of resin fine particles containing inorganic fine powder.

The average particle size of the composite fine particles is preferably in the range of 0.1 to 7.0 μm, particularly preferably in the range of 0.2 to 5.0 μm. If the average particle size of the composite fine particles is within this range, the stability and uniformity of the triboelectric charging properties of the toner will further improve, and the cleaning performance will further improve.

However, if the average particle size of the composite fine particles is too large, the triboelectric charging properties of the toner deteriorate, which tends to cause a decrease in image density. On the other hand, if the average particle size of the composite fine particles is too small, cleaning properties tend to be insufficient.

Here, the average particle size of the composite fine particles is determined using a laser diffraction particle size distribution analyzer "HELO3-CO" manufactured by SYMPATEC.
It refers to the volume-based average particle size measured by MPETITION/3J.

The content ratio of the composite fine particles in the toner is 0.01 to 5.
．． f) A range of % by weight is preferred, particularly a range of 0.1 to 3.0% by weight. If the content ratio is within this range, the above-mentioned effects of the composite fine particles will be fully exhibited. However, when the content of the composite fine particles is too large, the triboelectric charging properties of the toner become insufficient, which tends to cause a decrease in image density. On the other hand, when the content of the composite fine particles is too small, the cleaning properties of the toner tend to be insufficient.

Examples of the resin material constituting the composite fine particles include acrylic polymers (for example, the acrylic polymer described in JP-A-60-186851), acrylic-styrene copolymers (
For example, acrylic-styrenic copolymers described in JP-A-60-186852), polymers or copolymers of nitrogen-containing addition-polymerizable monomers (e.g., JP-A-60-1868)
Polymers or copolymers of nitrogen-containing addition-polymerizable monomers described in Japanese Patent Publication No. 53), polymers or copolymers of addition-polymerizable carboxylic acids (for example, addition polymerization described in JP-A-60-186868) polymers or copolymers of polycarboxylic acids), fluororesins (e.g., fluororesins described in Japanese Patent Application No. 62-67997), silicone resins (e.g., silicone resins described in Japanese Patent Application No. 131258/1980) ), polyolefin resins (for example, JP-A-52-891
The polyolefin resin described in Japanese Patent Application No. 66), etc. can be used.

The inorganic fine powders that make up the composite fine particles include silica, alumina, titania, barium titanate, aluminum titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, chromium oxide, cerium oxide, antimony trioxide, and oxide. Inorganic compounds such as zirconium, tungsten oxide, copper oxide, tin oxide, manganese oxide, boron oxide, silicon carbide, titanium carbide, boron carbide, silicon nitride, titanium nitride, boron nitride, and metals such as copper, aluminum, and zinc. Can be used.

The primary particle diameter of the inorganic fine powder is preferably in the range of 0.005 to 5 μm, particularly preferably in the range of 0.01 to 2 μm. If the primary particle size of the inorganic fine powder is within this range, the dispersibility of the inorganic fine powder into the resin fine particles can be improved. However, when the primary particle size of the inorganic fine powder is too large, it tends to be difficult to produce composite fine particles. On the other hand, when the primary particle size of the inorganic fine powder is too small, it tends to be difficult to produce composite fine particles, and the cleaning properties of the toner tend to deteriorate.

The content ratio of the inorganic fine powder in the composite fine particles is 10 to 95
A range of % by weight is preferred, particularly a range of 20 to 80% by weight. If the content of the inorganic fine powder is within this range, the abrasiveness and insulation properties of the composite fine particles will be in a more suitable range. However, if the content of the inorganic fine powder is too large, it becomes difficult to manufacture composite fine particles, and it becomes difficult to sufficiently encapsulate the inorganic fine powder. On the other hand, when the content of the inorganic fine powder is too small, the cleaning properties of the toner tend to deteriorate.

The composite fine particles constituting the toner of the present invention can be produced, for example, by the following method.

(1) A method of polymerizing the seven polymers of resin constituting fine resin particles in the presence of inorganic fine powder.

This method is a method in which inorganic fine powder is encapsulated by resin constituting resin fine particles, and it is important to increase the affinity between the resin and inorganic fine powder. Specifically, the following method can be applied. can.

(a) The surface of the inorganic fine powder is previously subjected to adsorption treatment or reaction treatment with organic polymers, surfactants, etc. to form a surface that has an affinity for the resin monomers that make up the resin fine particles, and this inorganic fine powder is used as a core. A method of polymerizing a resin monomer and encapsulating the inorganic fine powder with the resin.

et al.) in the presence of an inorganic fine powder, polymerizing a resin monomer constituting the resin fine particles to form a resin having an ionic group terminal with a polarity opposite to the surface charge of the inorganic fine powder,
A method of encapsulating inorganic fine powder with resin using the electrostatic attraction of both charges.

For example, this method can be applied to the ends of fine resin particles prepared in an emulsifier-free system because they are charged by the charges of decomposed fragments of the catalyst used in polymerization.

(2) A method in which composite fine particles are generated after pretreatment of inorganic fine powder.

Specifically, a thermoplastic resin is mixed with an inorganic fine powder, the two are kneaded, this is pulverized to produce a powder, this powder is dissolved in a solvent, and then this is mixed with a prize solvent for the thermoplastic resin. There are methods such as crystallizing composite fine particles by melting, or precipitating composite fine particles by cooling after melting.

(3) A method using emulsion polymerization.

A dispersion liquid is prepared by mixing the magnetic powder and a resin monomer constituting the resin fine particles. Next, the dispersion is emulsified in a solution containing a surfactant and subjected to emulsion polymerization to obtain fine particles containing magnetic powder.

The colored particles constituting the toner of the present invention are 1. (Particles containing an Ingu resin and a colorant as essential components, and may contain internal additives such as a charge control agent, a fixing property improver, and a magnetic material as necessary.

The binder resin is not particularly limited, and resins conventionally used as binder resins for toners can be used. Specifically, styrene resin, acrylic resin, styrene/acrylic copolymer resin, polyester resin, epoxy resin, polyurethane resin, polyimide resin, cellulose resin, polyether resin, etc. can be mentioned.

Colorants include carbon black, nigrosine dye,
Aniline blue, Calco oil blue chrome yellow,
Ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green offsalate, lamp black, rose benganope magnetic material, mixtures thereof, and the like can be used.

As the charge control agent, for example, nigrosine dyes, metal-containing azo dyes, metal complexes, etc. can be used.

As the fixing property improving agent, for example, polyolefin such as low molecular weight polypropylene can be used.

The magnetic substance is an internal additive mainly used when obtaining a magnetic toner, and alloys or compounds of iron such as various ferrites, magnetites, hematites, zinc, cobalt, nickel, manganese, etc. can be used.

The average particle size of the magnetic material is preferably 1 μm or less, particularly 0.5 μm or less.
It is preferably less than μm. The blending amount of the magnetic material is in the range of 20 to 70% by weight of the entire colored particles.

As a method for producing colored particles, a pulverization granulation method, a polymerization granulation method, etc. can be applied.

In the pulverization granulation method, a binder resin, a colorant, and other toner components used as necessary are mixed, melt-kneaded, pulverized, and classified to give a predetermined average particle size (1 to 30 μm).
This is a method for producing colored particles of about 1.0 m).

In the polymerization granulation method, a colorant and other toner components used as necessary are present in the monomers constituting the binder resin, and a polymerization reaction is carried out by suspension polymerization, emulsion polymerization, etc. This is a method for producing colored particles having an average particle size (approximately 1 to 30 μm).

The toner of the present invention contains colored particles and composite fine particles. Specifically, the colored particles and the composite fine particles are mixed and stirred, and the composite fine particles are electrostatically applied to the surface of the colored particles. to form a toner.

In the present invention, the toner may be constituted by further adding and mixing inorganic fine particles and the like from the outside to the toner obtained as described above. As such inorganic fine particles, for example, fine particles of silica, alumina, titania, etc. are preferable, and hydrophobic silica fine particles are particularly preferable.

The toner of the present invention may be a two-component toner that is mixed with a carrier to form a two-component developer, or a one-component toner that is composed of only toner without using a carrier. Good too.

〔Example〕

Examples of the present invention will be described below along with comparative examples, but t=W in the implementation of the present invention is not limited to these examples.

In addition, in the following, "part" represents "part by weight".

<Manufacture of composite fine particles> (1) Composite fine particles 1 Amorphous silicon carbide with an average primary particle diameter of 0.2 μm (
150 g of inorganic fine powder) and 6 g of methyltrimethoxysilane were added to toluene, and the temperature was raised to 100°C while stirring.
The mixture was heated at that temperature for about 2 hours, and then the toluene was distilled off. Wash and dry the product,
Inorganic fine powder 1 with a modified surface was obtained.

10 g of this inorganic fine powder 1, 50 g of styrene (vinyl monomer), and AIBN (azobisisobutyronitrile:
Using 1 g of polymerization initiator) and an appropriate amount of Aerosil ○T (sulfosuccinic acid di-2-ethylhexyl ester sodium salt: surfactant), the mixture was heated in ethanol for 70 minutes under a nitrogen stream.
The reaction was carried out at ℃ for about 2 hours, and the average particle size was 0.3.
Composite fine particles 1 of μm size were manufactured.

When the surface of this composite fine particle 1 was observed using an electron microscope, it was confirmed that almost no silicon carbide particles were observed on the surface, and that silicon carbide particles were contained inside the resin fine particles.

(2) Composite fine particles 2 In the production of composite fine particles 1, inorganic fine particles 2 were prepared in the same manner, except that 150 g of amorphous titanium oxide with an average primary particle diameter of 0.4 μm was used as the inorganic fine powder. Obtained.

Next, Composite Fine Particles 2 having an average particle diameter of 0.5 μm were produced in the same manner as Composite Fine Particles 1 except that Inorganic Fine Powder 1 was changed to 10 g of the above-mentioned Inorganic Fine Powder 2 and styrene was changed to 50 g of methyl methacrylate.

When the surface of the composite fine particles 2 was observed using an electron microscope, it was confirmed that titanium oxide particles were hardly observed on the surface and were contained inside the resin fine particles.

(3) Composite fine particles 3 In the production of composite fine particles 1, 150 g of amorphous aluminum oxide with an average primary particle diameter of 0.8 μm was added to the inorganic fine powder.
Surface-modified inorganic fine powder 3 was obtained in the same manner except that the method was changed to .

Next, inorganic fine powder 1 was changed to 10 g of the above-mentioned inorganic fine powder 3, but in the same manner as composite fine particles 1, the average particle size was 1.0 μm.
Composite fine particles 3 of m were manufactured.

When the surface of the composite fine particles 3 was observed using an electron microscope, it was confirmed that almost no aluminum oxide particles were observed on the surface, and that they were contained inside the resin fine particles.

<Manufacture of colored particles> (1) Colored particles 1 Styrene-acrylic copolymer resin 60 parts (S t
: BA=85 :15) Magnetite 45 parts Nigrosine dye'#+ (charge control agent) 2 parts Low molecular weight polypropylene 3 parts (3t represents styrene and BA represents butyl acrylate) After mixing the above materials , kneaded, crushed and classified to obtain colored particles 1 having an average particle size of 11.0 μm.

(2) Colored Particles 2 Polyester resin 100 parts Carbon black 4 parts Low molecular weight polypropylene 3 parts or more of the materials were mixed, ground, crushed, and classified to obtain colored particles 2 with an average particle size of 12.0 μm.

<Example 1> In the colored particles 1, 0.4% by weight of inorganic fine particles rR-812J (hydrophobic silica fine particles, average particle diameter of 3 nm, manufactured by Nippon Aerosil Co., Ltd.) and 0.4% by weight of composite fine particles 1 were added.
These were mixed using a V-type mixer to obtain toner A of the present invention.

<Example 2> In the colored particles 1, 0.6% by weight of inorganic fine particles rR-972J (hydrophobic silica fine particles, average diameter of secondary particles 15 nm, manufactured by Nippon Aerosil Co., Ltd.) and 0.6% by weight of composite fine particles 2 were added. These were mixed using a V-type mixer to obtain toner B of the present invention.

<Example 3> 0.4% by weight of inorganic fine particles rR-972J and 0.8% by weight of composite fine particles 3 were added to colored particles 1, and these were mixed in a V-type mixer to form the inventive particle. Toner C was obtained.

Comparative Example 1> In Example 1, composite fine particles 1 were
0.6% by weight of composite fine powder 1 (particles formed by adhering silicon carbide fine particles (20 parts) on the surface of acrylic polymer particles (100 parts)) described in Examples of Publication No. 143
Toner a for comparison was obtained in the same manner except that the following was changed.

Comparative Example 2> In Example 2, composite fine particles 2 were prepared with an average particle size of 0.4.
A comparative toner b was obtained in the same manner except that the amount of acrylic polymer particles of μm was changed to 0.6% by weight.

<Example 4> 0.4% by weight of inorganic fine particles rR-812J and 0.6% by weight of composite fine particles 1 were added to colored particles 2, and these were mixed in a V-type mixer to form the inventive particle. Toner D was obtained.

<Example 5> 0.6% by weight of inorganic fine particles rR-972J and 0.3% by weight of composite fine particles 2 were added to colored particles 2, and these were mixed using a V-type mixer to form the inventive compound. Toner E was obtained.

Comparative Example 3 A comparative toner C was obtained in the same manner as in Example 4, except that the amount of composite fine particles 1 was changed to 1.0% by weight of the composite fine powder 1 used in Comparative Example 1.

<Comparative Example 4> Comparative toner d was obtained in the same manner as in Example 5, except that the composite fine particles 2 were changed to 0.8% by weight of the acrylic polymer particles used in Comparative Example 2.

Test 1> Using each of the toners A-C of the present invention and the comparative toner ab as a one-component developer, a non-contact type developer equipped with an organic photoreceptor and in which an oscillating electric field is applied to the development area was constructed. Using a prototype electrophotographic copying machine equipped with a single-component developer, we conducted a test in which copy images were continuously formed 200,000 times under environmental conditions of a temperature of 20°C and a relative humidity of 55%.
Cleanability, damage to the photoreceptor, image density, transportability, and scattering of composite particles were evaluated. The results are shown in Table 1 below.

<Test 2> Toners D and E of the present invention and toner C1d for comparison
3 parts each, and styrene on the surface of the ferrite core material.
Carrier coated with acrylic copolymer resin (styrene: methyl methacrylate = 3 nia) (average particle size 80 μm)
m) to prepare a two-component developer.

Using these two-component developers, copies were made using an electrophotographic copying machine rU-Bix 5000J (manufactured by Konica) equipped with a selenium-based photoreceptor under environmental conditions of a temperature of 20°C and a relative humidity of 55%. A test was conducted in which images were continuously formed on 200,000 sheets, and in the same manner as Test 1, cleaning performance, damage to the photoreceptor, image density, and scattering of composite fine particles were evaluated. The results are shown in Table 2 below.

In the above Tests 1 and 2, the evaluation method is as follows.

[Cleanability]

The surface of the photoreceptor immediately after being cleaned with a cleaning blade was visually observed, and judgment was made based on the presence or absence of deposits on the surface of the photoreceptor.

The evaluation is "○" if there is almost no deposits observed and the product is in good condition, "△" if some deposits are observed but at a practical level, and "△" if a lot of deposits are observed and there is a problem in practical use. was marked as "x".

[Damage to photoreceptor]

The surface of the photoreceptor was visually observed to check for damage.

[Picture @! concentration〕

The relative concentration was measured using a "Sakura Densitometer" manufactured by Konica ■. The evaluation is 10-: when the relative concentration is 1.25 or more, and 10-: when the relative concentration is 1.1 or more and 1.25 drops.
△", and cases where the score was less than 11 were marked "x".

[Transportability]

Visually observe the surface of the developing sleeve, and if there is almost no adhesion of composite fine particles and the conveyance is good, the rating is "O".
, Cases where adhesion to the developing sleeve was observed and transportability was unstable were rated "x".

[Scattering of composite fine particles - The back side of the member that regulates the layer thickness of the developer was visually observed to check for the presence or absence of scattering of composite fine particles.

As a result of the above tests, one-component toner A-
It is clear that when C is used, it is excellent in all aspects of cleaning performance, damage to the photoreceptor, image density, transportability, and scattering of composite fine particles. Furthermore, it is clear that even when the two-component toners D and E according to the present invention are used, they are excellent in all aspects of cleaning performance, damage to the photoreceptor, image density, and scattering of composite fine particles.

That is, when the toner of the present invention is used, the surface of the photoreceptor can always be maintained in a good condition, and good cleaning properties can be exhibited.

Furthermore, when the toner of the present invention is made of one component, the composite fine particles do not scatter or stick to the developing sleeve, so the transportability and triboelectric charging properties are stable over a long period of time, and there is no problem with toner scattering or image defects. A stable image with high image density can be formed 200,000 times without any problems.

Further, even when the toner of the present invention is two-component, a stable image with high image density can be formed over 200,000 times without toner scattering.

On the other hand, when one-component toner a was used for comparison, the composite fine powder contained in the toner did not contain any inorganic fine powder, and silicon carbide fine particles were fixed to its surface. Because the surface of the photoreceptor is easily damaged, cleaning performance is poor, and the number of image formations is reduced to 1.
After 00,000 cycles, the composite fine powder stuck to the developing sleeve, making the conveyance unstable and causing a decrease in image density.

When using one-component toner b for comparison, the acrylic polymer particles contained in the toner did not contain any inorganic fine powder inside, and no inorganic fine powder was present on the surface either. 1. Cleanability was poor, and the acrylic polymer particles stuck to the developing sleeve after 30,000 image formations, resulting in unstable conveyance and a decrease in image density.

When the comparative two-component toner C was used, the composite fine powder contained in the toner contained no inorganic fine powder, but only silicon carbide fine particles were fixed to its surface. , the surface of the photoreceptor is easily damaged;
Cleanability was poor, and image density decreased after 120,000 image formations.

When using the comparative two-component toner d, there was no inorganic fine powder inside the acrylic polymer particles contained in the toner, and no inorganic fine powder was present on the surface. The cleaning properties were poor, and the image density decreased after 100,000 image formations.

〔Effect of the invention〕

As explained above, in the present invention, since composite fine particles containing inorganic fine powder inside the resin fine particles are used, the hardness of the composite fine particles is appropriate, and suitable abrasiveness is achieved without damaging the surface of the photoreceptor. and exhibits good leaning properties.

Claims (1)

[Scope of Claims] A toner for developing an electrostatic image, comprising colored particles made of at least a binder resin and a colorant, and composite fine particles made of fine resin particles containing inorganic fine powder.