JP3230167B2 - Toner and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner having a stable developing property for a long period of time when an associative amorphous polymerization toner is used in a developing method of a thin layer forming method. The present invention relates to an image forming method using a stable toner and a thin layer forming and developing method.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made to reduce the particle size of toner in order to improve image quality in electrophotography. However, in toners obtained by the generally used melt-kneading and pulverization method, there is a limit in controlling the toner particle size, and the particle size is specified to be substantially 8 μm or less, particularly 6 μm or less. It is very difficult to produce a stable distribution. Therefore, a highly pulverizable linear polyester or a styrene acrylic resin having a reduced molecular weight is used. However, when such a resin is employed, the toner may be finely powdered due to stress such as stirring in a developing device, or an external additive added for imparting fluidity may be buried in the toner surface. Cause problems. In addition, it has a disadvantage that it is expensive in terms of manufacturing cost.

On the other hand, polymerized toners are being studied in a wide variety of ways rapidly because of the advantage that stable and efficient production can be achieved instead of the pulverization method as a method for reducing the particle size of the toner. However, in the case of the polymerized toner, the problem of a decrease in durability due to the burying of the external additive accompanying the reduction in the particle size of the toner remains.

[0004]

As described above, the polymerized toner is a method which can easily obtain a toner having a small particle size as compared with the pulverized toner. As a method for producing this polymerization toner, a method of adjusting the toner by suspension polymerization has been proposed. However, this method has a problem in that the resulting toner has a spherical shape and thus has a high adhesive force to the photoreceptor, so that the cleaning property in blade cleaning is reduced, and so-called cleaning failure occurs.
For this purpose, a method has been proposed in which the shape is defined as in Japanese Patent Application Laid-Open No. Sho 61-279864, and a cleaning failure is solved by using a shape within that range. Further, Japanese Unexamined Patent Application Publication No. 60-76766 and the like also propose a toner having a large unevenness. However, these toners can be made amorphous, so that there is no problem in cleaning properties.
The cohesiveness of the toner itself is reduced due to the presence of unevenness, and in a developing method such as a thin layer forming method which receives a large stress at the time of development, a large shear stress is applied to the toner at the time of forming a thin layer and the toner is pulverized and adheres to a carrier or the like. Problems, such as the problem of sticking to the sleeve and the like. Further, even with these polymerization toners, the problem that the external additive is easily buried because the heat capacity of the particles is small by reducing the particle size as described above remains.

On the other hand, a technique using a combination of a large particle size and a small particle size as an external additive is disclosed in JP-A-57-17986.
6 known. With this technology, it is possible to prevent the embedding of the small particle size external additive by the presence of the large particle size external additive, but the presence of the large particle size external additive prevents the above-mentioned amorphous polymerization. When used, these particles act as nuclei to cause a problem of promoting pulverization.

As described above, in the prior art, there is no known developer which can prevent the destruction of particles and satisfy the durability in the amorphous polymerization toner.

Further, the developing method of transporting the developer layer as a thin layer to the developing area can reduce the triboelectric charging property of the toners regardless of contact / non-contact development, and generates so-called reverse polarity toner. This method is known as a good developing method having a small transfer rate and a small fringe. Furthermore, the developing method of transporting the developer mixed with the carrier to the developing area in a thin layer,
Non-contact development can be performed, and color superposition on a photoreceptor becomes possible, which is suitable as a developing method for a small full-color copying machine. Furthermore, in the one-component developing method, by adopting a thin layer forming method, it is possible to reduce the triboelectric charging property between the toners, to prevent the occurrence of reverse polarity, and to achieve a high transfer rate developing method. Becomes Also,
The non-magnetic one-component developing method is a developing method that does not use a carrier, and is different from the conventional magnetic one-component developing method, and has attracted attention as a compact developing method that can be colored because it does not use a magnetic material. This non-magnetic one-component developing method requires a developing method of transporting the non-magnetic toner in a thin layer to a developing area. As described above, there is an increasing demand for a method for transporting the developer to the development area in a thin layer. Even in this developing method, it is required to improve the image quality by reducing the toner particle size as described above.

In this case, since a large shear stress is applied to the toner as described above, it is necessary to further improve the durability and prevent the toner from being crushed.

An object of the present invention is to improve the durability of an irregular polymerization toner used in a thin layer forming type developing system, and further to improve the development stability. Things.

[0010]

The object of the present invention is to achieve a primary particle containing at least a resin and a colorant having a primary particle diameter of 0.1 to 2.0 μm.
volume average particle size obtained by associating resin fine particles of m
In the case of a toner comprising irregularly colored particles having a size of about 8 .mu.m and an external additive, the external additive comprises three types of A, B, and C, and the three types have peaks (Da, Db, Dc) having the following number particle diameters. ), And the external additives are added at the following surface occupancy with respect to the surface area of the toner. Can be achieved.

External additive A: Da = 7-20 nm, area occupancy = 30-90% External additive B: Db = 20-50 nm, area occupancy = 50-100% External additive C: Dc = 50- 150 nm · area occupancy = 50 to 100% Alternatively, a resin having a volume average particle diameter of 2 to 8 μm obtained by associating resin fine particles containing at least a resin and a colorant and having a primary particle diameter of 0.1 to 2.0 μm is associated. In a toner comprising fixed colored particles and an external additive, the external additive is added at a primary particle diameter of at least 7 to 20 nm and a surface area occupancy of 30 to 90% with respect to the surface area of the irregularly shaped colored particles. The inorganic fine particles E have a primary particle diameter of 20 to 50 nm and a surface area occupancy of 50 to 10 nm.
Use of toner characterized by being composed of 0% of inorganic fine particles F and organic fine particles G having a primary particle diameter of 50 to 150 nm and a surface area occupancy of 50 to 100% in a thin layer forming type developing method. Can be achieved by doing

The above-mentioned external additives may be of the same type or different types.

Further, as a method of forming a thin layer, there is a method in which a developer mixed with a carrier is transported in a thin layer to a developing area by a pressure control method. Further, a method in which a magnetic toner containing a magnetic material is transported in a thin layer to a developing area for development, or a developing method in which only a non-magnetic toner is transported in a thin layer to a developing area can be suitably used.

The inorganic fine particles of the above-mentioned external additives may be of the same type or different types. The purpose can be achieved by adjusting the particle size to this range.

Further, as a method of forming a thin layer, there is a method in which a developer mixed with a carrier is conveyed in a thin layer to a development area by a magnetic force or a pressure regulating method. Further, a method in which a magnetic toner containing a magnetic material is transported in a thin layer to a developing area for development, or a developing method in which only a non-magnetic toner is transported in a thin layer to a developing area can be suitably used.

The irregular colored particles include suspension polymerization,
Emulsion polymerization, associative polymer particles made by seed polymerization, etc., mainly styrene, acrylic copolymer-based primary particles, primary particles of a thermoplastic polymer having an acidic polar group or a basic polar group A coloring agent is added to 0.1 to 2.0 μm, and the primary particles are aggregated by binding force such as ionic bond, hydrogen bond, metal coordination bond, Van der Waals force, etc. And,
Further, a charge control agent, a wax and the like are added as required.

The primary particles are obtained, for example, by an emulsion polymerization method. Examples of the monomer for obtaining the primary particles include a styrene monomer, an acrylic monomer, and other monomers having a polar group.

The styrene monomer includes styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene,
α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, p-
n-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene,
p-Chlorostyrene, 3,4-dichlorostyrene and the like.

The acrylic monomers include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic acid- 2-ethylhexyl, stearyl acrylate,
2-chloroethyl acrylate, phenyl acrylate, α-
Methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-methacrylic acid
Butyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate,
Examples thereof include 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

Other monomers having a polar group include:
The following are mentioned.

(1) Having an acidic polar group Acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monobutyl maleate ester, monooctyl maleate ester, or a metal (Na, Carboxyl group (-C, such as Zn)
Α, β-ethylenically unsaturated compound having OOH).

Sulfonated styrene or its Na
Α, β-ethylenically unsaturated compounds having a sulfone group (—SO ₃ H), such as salts, allylsulfosuccinic acid, octyl allylsuccinate or Na salts thereof.

(2) Those having a basic polar group: dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, quaternary ammonium salts of these compounds, 3-dimethylaminophenyl acrylate, 2-hydroxy 3- (meth) acrylic acid esters of aliphatic alcohols having 1 to 12 carbon atoms having an amine group such as -3-methacryloxypropyltrimethylammonium salt or a quaternary ammonium base.

(Meth) acrylic amide or N such as acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide (Meth), optionally monomeric or di-alkyl substituted above
Acrylic amide.

[0025] Vinyl pyridine, vinyl pyrrolidone, vinyl N-methylpyridinium chloride, vinyl
A vinyl compound substituted with a heterocyclic group having N as a ring member such as N-ethylpyridinium chloride.

N, N-diallylmethylammonium chloride, NN-diallylethylammonium chloride, etc.
N-diallylalkylamine.

In the monomers for obtaining the primary particles, the mixing ratio (weight ratio) of the styrene monomer and the acrylic monomer is preferably from 90 to 20:10 to 80, particularly preferably from 70 to 30:30. ~
70 is preferred.

The proportion of the other monomer having a polar group is preferably from 0.05 to 30 parts by weight, more preferably from 1 to 20 parts by weight, based on 100 parts by weight of the total of the styrene monomer and the acrylic monomer.
Parts by weight are preferred.

(Examples of Radical Polymerization Initiator) Examples of the water-soluble polymerization initiator include potassium persulfate and ammonium persulfate. Further, as the oil-soluble polymerization initiator, benzoyl peroxide, t-butyl peroxide, lauryl peroxide, t-butyl hydroxy peroxide, peroxides such as cumene hydroxy peroxide, azobisisobutyronitrile, Azobis compounds such as azobisisovaleronitrile and azobiscyclohexanecarbonitrile are exemplified. The amount of the polymerization initiator to be used may be the same as in the case where a normal polymerization reaction is performed. That is, the amount of addition varies depending on the required degree of polymerization, etc.
It is good to add 05 to 10% by weight. The polymerization initiator used can be used in combination of the above.

The polymerization composition for obtaining the primary particles may contain various additives as necessary. Examples of such additives include a colorant, a release agent, and a charge control agent.

Examples of the coloring agent 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 oxalate, lamp black, and rose. Bengal, mixtures thereof, and the like.

Examples of the release agent include polyolefins having a low softening point, high melting point paraffin wax, silicone varnish, aliphatic esters or partially saponified products thereof, aliphatic amide compounds, higher alcohols and the like.

Examples of the charge control agent include metal complex dyes, nigrosine dyes, and ammonium salt compounds.

When a magnetic toner is obtained, magnetic particles are contained as an additive in the toner particles. As such magnetic particles, particles such as ferrite and magnetite having a number average particle diameter of 0.1 to 2 μm can be used.

As the resin material of the present invention, materials generally used conventionally are preferably used.

As the coloring agent, inorganic pigments, organic pigments, and organic dyes are used. These pigments and / or dyes may be used alone or in combination of two or more as needed.

As the colorant, a material generally used in the past can be used. In a magnetic one-component developer, a magnetic material can be used as the colorant. However, the two-component developer and the non-magnetic one-component developer do not use a magnetic material as a coloring agent.

As a carrier used as a two-component developer, a generally known carrier obtained by coating a core material such as iron powder, glass beads or ferrite with a resin or the like can be used. Further, a resin dispersion type carrier may be used.

The volume average particle diameter of the carrier used in the present invention is preferably from 20 to 100 μm, and particularly preferably from 30 to 60 μm.

In the present invention, in order to make the coating amount of the external additive constant according to the shape of the irregularly shaped colored particles adjusted by the polymerization method, the external additive A or After adding 30% to 90%, preferably 50% to 70% of E, the external additive B or F is added to 50% to 100%, preferably 70% to 9%.
0%, 50% to 100%, preferably 70% to 90% of the external additive C or G
It is important to add%.

That is, the external additive A or E is an external additive composed of inorganic fine particles having a small particle diameter, and is a material for eliminating the cohesiveness between the small particle toners and improving the fluidity of the toner. . The fluidity of the toner can be improved by adding a material capable of giving a spacer effect between the toners. However, in the case of a so-called small particle size toner (2 to 8 μm), 7 nm to 2 nm is used.
By using the inorganic fine particles in the range of 0 nm, a sufficient fluidity imparting effect is exhibited. On the other hand, when the occupation ratio of the colored particles to the surface area is 30% or less, the effect of imparting fluidity decreases, and no fluidity is imparted. Further, when the surface area occupancy of the colored particles exceeds 90%, the external additive becomes easy to move,
Charging control becomes difficult, and the environment dependence of charging also increases.
Further, since the external additive having such a small particle diameter is buried severely, the charge control effect of the external additive greatly fluctuates. The external additive B or F composed of inorganic fine particles is a particle having the charge control function, and it has been found that the presence of the particle stabilizes the charge. It is important that the external additive B or F having a particle diameter in this intermediate region has a primary particle diameter in the range of 20 to 50 nm. That is, the material having the particle size in this range has a large effect of imparting chargeability. When the particle size is larger than this, the effect of imparting charge to the colored particles is small. The same applies to the surface area occupancy of the colored particles, which is 50%
Below, the contribution is small and the effect is difficult to appear, 100%
On the other hand, when the value exceeds 3, the release of the external additive becomes intense, which causes a problem that charge controllability is reduced.

However, in the case of a toner having a small particle diameter, the thermal energy of the toner itself increases due to stress, and the surface softening becomes severe. Changes will be intense. For this purpose, an external additive C having a primary particle diameter (Dc) of 50 to 150 nm is added at a surface area occupation ratio of 50 to 100% to the toner for the purpose of further preventing the external additive from being buried. Can be prevented from being buried. If the surface area occupancy of the toner is less than 50%, burying prevention does not work sufficiently, and if it exceeds 100%, a large amount of external additives having a large particle diameter are present on the toner surface, and the toner itself has a chargeability. Is undesirably linked to toner scattering. As described above, by using the external additive A / B / C within the intended range, the intended life of the developer and a high image quality can be achieved.

According to another aspect of the present invention, there is provided an external additive E / F.
/ G toner. As described above, in the case of a toner having a small particle diameter, the thermal energy storage of the toner itself increases due to stress and the surface softening becomes severe. Therefore, the external additive E / F alone causes a drastic change in chargeability and fluidity of the toner due to burying. Become. For this purpose, the external additive G having a primary particle diameter of 50 to 150 nm is added at a surface area occupation ratio of 50 to 100% with respect to the toner for the purpose of preventing the external additive from being buried. This can be prevented. Organic fine particles can be preferably used as the external additive G.
That is, it has been found that when the organic fine particles have a low hardness as particles, when stress is applied to the particles, the stress on the particles is greatly reduced by the elastic effect, and the durability is improved. When the organic fine particles have a surface area occupancy of less than 50% with respect to the colored particles, the burying prevention does not work sufficiently, and when the occupancy exceeds 100%, a large amount of external additives having a large particle size are present on the surface of the colored particles. Therefore, the chargeability of the toner itself is reduced, and the toner is scattered. As described above, the durability is improved by using the inorganic fine particles and the organic fine particles having the primary particle diameters in combination.

In the present invention, the following materials can be used as the external additive having the above-mentioned primary particle diameter. The primary particle size can be measured with a transmission electron microscope.

The inorganic fine particles include inorganic oxides and nitrides, which are used in the following places.

External additive A: silicon oxide / aluminum oxide /
Titanium oxide, zirconium oxide, boron nitride, silicon carbide External additive B: silicon oxide, aluminum oxide, titanium oxide,
Zirconium oxide / boron nitride / silicon carbide External additive C: titanium oxide / silicon oxide / strontium titanate / barium titanate / magnesium titanate The above external additives can be used after being hydrophobized by various coupling agents. It is.

External additive E: silicon oxide / aluminum oxide /
Titanium oxide, zirconium oxide, boron nitride, silicon carbide External additive F: silicon oxide, aluminum oxide, titanium oxide,
Zirconium oxide / boron nitride / silicon carbide External additive G: Organic fine particles, which can be adjusted by an emulsion polymerization method, a soap-free polymerization method, or a suspension polymerization method.
The emulsion polymerization method and the soap-free polymerization method are preferred, and those prepared by the soap-free polymerization method are more preferred. The reason for this is that in organic fine particles prepared by the emulsion polymerization method, a large amount of a low molecular weight surfactant is present on the surface, and this material is released from the organic fine particles over a long period of use and migrates to the toner or carrier, This is because there is an inherent problem of inhibiting charging. The organic fine particles prepared by the soap-free polymerization method do not have a low molecular weight surfactant, so that the migration of the surfactant to the toner or carrier is small, and the long-term stability is further improved. .

(Specific examples of polymerizable monomers) Styrenes such as styrene, o-methylstyrene, m-methylstyrene, α-methylstyrene, pt-butylstyrene, chlorostyrene; acrylic acid, methyl acrylate, acrylic Acrylic acid such as ethyl acrylate, butyl acrylate, isopropyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, dodecyl acrylate, stearyl acrylate and the like; methacrylic acid, methyl methacrylate, ethyl methacrylate, methacrylic acid Butyl, isopropyl methacrylate, 2-ethylhexyl methacrylate,
Methacrylic acid and its esters such as octyl methacrylate, dodecyl methacrylate, stearyl methacrylate, lauryl methacrylate, glycidyl methacrylate, and hydroxyethyl methacrylate; and dimethylaminomethyl acrylate, dimethylaminomethyl methacrylate, and acrylic acid Amino esters of acrylic acids, such as dimethylaminoethyl, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, and siethylaminoethyl methacrylate; quaternary ammonium salts of the amino esters of acrylic acids; vinyl pyridine, vinyl pyrrolidone And other radically polymerizable monomers such as nitrogen-containing vinyl compounds.

As the external additive G, a combination of, for example, a styrene-acrylic material can be preferably used. As the softening point and the glass transition point, from the viewpoint of preventing fusion to the sleeve, the softening point is 130 to 200 ° C,
The glass transition point is preferably from 50 to 120 ° C. Further, organic fine particles crosslinked with ethylene glycol, dimethacrylate, divinylbenzene or the like may be used as G. still,
In the case of inorganic fine particles, the external additives may be used after being rendered hydrophobic by various coupling agents.

As the developing method used in the present invention, a developing method of a thin layer forming method can be suitably used.

The thin layer forming method is a developing method in which a developer layer is transported in a developing area with a thickness of 20 to 500 μm. As a method of transporting the developer, a method of transporting the developer by regulating the developer by a pressure regulating rod that is in pressure contact with the developing sleeve by a magnetic blade or a magnetic force,
There is a method in which a developer layer is regulated to a thin layer by a urethane blade or a phosphor bronze plate which is in contact with the developing sleeve, and is conveyed.

The developer used in the present invention may be a two-component developer prepared by mixing with a carrier, a non-magnetic one-component developer not using a carrier, or a magnetic material having a holding force due to magnetic force by containing a magnetic powder in a toner. Used as toner and the like.

[0053]

【Example】

Example 1 Toner Preparation Example A monomer mixture of 80 parts of styrene, 15 parts of butyl acrylate and 5 parts of methacrylic acid in an aqueous solution of 100 parts of water, 1 part of polyoxymethylene alkyl ether, 1.5 parts of sodium alkylbenzenesulfonate and 0.5 part of potassium persulfate. Was added dropwise with stirring to emulsify, and then polymerized for 8 hours with stirring to obtain primary particles having a volume average particle size of 0.3 μm. Then, a liquid obtained by adding 5 parts of carbon black, 400 parts of water, and 5 parts of an azo metal-containing complex pigment as a charge control agent to 200 parts of the emulsion was added and stirred at 30 ° C. for 2 hours while stirring and dispersing with a slasher. did. Then, the temperature was raised to 70 ° C. while maintaining the stirring, and maintained for 3 hours. During this time, microscopic observation was performed to confirm that the primary particles were associated and secondary particles were formed.
After cooling, the dispersion was filtered, washed with water, and dried to obtain irregular colored particles. This has a volume average particle size of 5.5 μm.

The coloring particles obtained as described above were mixed with an external additive in the materials and formulations shown in the following table to obtain a developer of the present invention.

[0055]

[Table 1]

[0056]

[Table 2]

Evaluation of Developer A two-component developer was prepared by mixing a ferrite carrier coated with a styrene / acrylic resin and having a volume average particle diameter of 60 μm so that the toner concentration was 7%, and used.

The evaluation was carried out using a digital copying machine 9028 made by Konica, which was modified to use a developing device capable of transporting the developer to the developing area in a layer of about 150 μm by a pressure regulating rod with a magnetic force. Carried out. The conditions for the evaluation are shown below.

Photoreceptor surface potential = -550 V DC bias = -250 V AC bias = Vp-p: -50 to -450 V AC frequency = 1.8 kHz Dsd = 300 μm Pressing regulation pressure = 10 kgf / mm Pressing regulation rod = SUS416 (magnetic stainless steel) ) / Diameter = 3mm Developer layer thickness = 150μm Developing sleeve diameter = 20mm Put the developer adjusted above into the developing unit and print 20,000 sheets under low temperature and low humidity environment (10 ° C / 10% RH). Table 3 shows the results of evaluation of problems occurring on the image and changes in cleaning properties and density. The density is an absolute reflection density using Macbeth RD-918.

[0060]

[Table 3]

As is apparent from Table 3, the toner of the present invention has excellent performance without image defects.

Example 2 Toner Preparation Example 80 parts of styrene, 15 parts of butyl acrylate and 5 parts of methacrylic acid were added to an aqueous solution of 100 parts of water, 1 part of polyoxymethylene alkyl ether, 1.5 parts of sodium alkylbenzenesulfonate and 0.5 part of potassium persulfate. The resulting mixture was dropped and emulsified with stirring, and then polymerized for 8 hours with stirring to obtain primary particles having a volume average particle size of 0.3 μm. Then, a liquid obtained by adding 5 parts of carbon black, 400 parts of water, and 5 parts of an azo metal-containing complex pigment as a charge control agent to 200 parts of the emulsion was added and stirred at 30 ° C. for 2 hours while stirring and dispersing with a slasher. did. Then, the temperature was raised to 70 ° C. while maintaining the stirring, and maintained for 3 hours. During this time, microscopic observation was performed to confirm that the primary particles were associated and secondary particles were formed.
After cooling, the dispersion was filtered, washed with water, and dried to obtain irregular colored particles. This has a volume average particle size of 5.5 μm.

An external additive was added and mixed with the coloring particles obtained as described above in the materials and formulations shown in the following table to obtain a developer of the present invention.

The organic fine particles were prepared by a soap-free polymerization method and have the following physical properties.

* St-BA organic fine particles: primary particle diameter = 60 nm
Softening point = 150 ℃ ・ Tg = 63 ℃ ＊ St-2EHA organic fine particles: primary particle diameter = 100nm ・ softening point = 175
℃ ・ Tg = 65 ℃ ＊ MMA organic fine particles: primary particle diameter = 140nm ・ softening point = 180
℃ ・ Tg = 100 ℃

[0066]

[Table 4]

[0067]

[Table 5]

(Evaluation of Developer) In the same manner as in Example 1, the developer adjusted as described above was charged into a developing device, and 20,000 sheets were printed under a normal temperature and low humidity environment (20 ° C./20% RH). Table 6 shows the results of evaluation of the problems that occur on the image and changes in the cleaning property and density. The density is an absolute reflection density using Macbeth RD-918.

[0069]

[Table 6]

From Table 6, it can be seen that the toner of the present invention is an excellent toner having no image defects as compared with the comparative example.

[0071]

The toner of the present invention is free from character dust and character misalignment over a long period of time in the formation of monochrome and full-color images without being affected by the toner shape. It can be seen that no stable color image is formed. Furthermore, color reproduction over a wide range can be achieved by maintaining stable developability,
Also, excellent image quality can be provided under high temperature, high humidity, low temperature, low humidity and the like.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-51164 (JP, A) JP-A-2-187768 (JP, A) JP-A-63-282758 (JP, A) JP-A-63-282 282756 (JP, A) JP-A-63-186253 (JP, A) JP-A-63-289559 (JP, A) JP-A-4-204658 (JP, A) JP-A-62-174772 (JP, A) JP-A-4-337738 (JP, A) JP-A-63-131149 (JP, A) JP-A-4-177275 (JP, A) JP-A-4-69685 (JP, A) JP-A-63-250653 (JP, A) JP-A-4-307558 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (6)

(57) [Claims] 1. Amorphous colored particles having a volume average particle diameter of 2 to 8 μm obtained by associating resin fine particles having a primary particle diameter of at least 0.1 to 2.0 μm containing at least a resin and a colorant, and an external additive. Wherein the external additive is AB
C, which are inorganic fine particles having peaks (Da, Db, Dc) in the number particle diameters shown below, and in which each external additive has the following surface occupancy with respect to the toner surface area. A toner characterized in that it is added at a ratio of: External additive A: Da = 7-20 nm, area occupancy = 30-90% External additive B: Db = 20-50 nm, area occupancy = 50-100% External additive C: Dc = 50-150 nm, area Occupancy = 50-100% 2. The toner according to claim 1, wherein a magnetic powder is used as a coloring agent. 3. An image forming method, comprising: forming a developer layer containing the toner on a development carrier to a thickness of 20 to 500 μm; 4. An amorphous colored particle having a volume average particle diameter of 2 to 8 μm obtained by associating resin fine particles having a primary particle diameter of at least 0.1 to 2.0 μm containing at least a resin and a colorant, and an external additive. And inorganic particles E and primary particles, wherein the external additive has at least a primary particle diameter of 7 to 20 nm and a surface area occupancy of 30 to 90% of the surface area of the irregularly colored particles. The surface area occupancy is 20-50 nm in diameter.
A toner comprising 50 to 100% of inorganic fine particles F and organic fine particles G having a primary particle diameter of 50 to 150 nm and a surface area occupancy of 50 to 100%. 5. The toner according to claim 4, wherein a magnetic powder is used as a coloring agent. 6. The developing device according to claim 4, wherein
An image forming method comprising: forming a thin layer of the toner described in (1) to a thickness of 20 to 500 μm;