JPH1083120A - Image forming method and developer used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method by which an excellent image density can be obtained even when electric potential contrast of a photoreceptive substance is low and to provide a developer suitable for the method. SOLUTION: In the image forming method by which an electrostatic latent image is developed in a developing region after the electrostatic latent image is formed on a latent image carrying member, the electrostatic latent image has difference of 100 to 400V in absolute value between surface potential at a dark part and surface potential at a bright part, a space between the latent image carrying member and a developer carrying member (developing sleeve) in the developing region is made to be within the range of 0.4 to 0.7mm. On the developing sleeve, a two-component developer for dry processing composed of a toner and a carrier containing a ferroelectric substance in a coating layer is supplied or a thin layer of nonmagnetic or magnetic one-component toner is formed via a toner layer regulating member and is supplied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and a one-component or two-component developer useful for carrying out the method.

[0002]

2. Description of the Related Art In low-potential development with a potential contrast of 400 V or less, it is necessary to perform development by effectively applying a developing electric field in a development area in order to maintain a high image density. For this reason, it is important to define the distance (interval) between the latent image carrier and the developing sleeve (developer carrier). If this distance is 0.4 mm or less, the distance tends to vary by about several tens of μm due to the eccentricity of the developing sleeve and the like, so that the background stain easily occurs and the image unevenness easily occurs. On the other hand, when the thickness exceeds 0.7 mm, the electric field becomes small, the image density is low, and an edge effect is generated. Inferior.

In view of the above, a carrier coated with a high-resistance substance contains a high-permittivity substance in the high-resistance substance (Japanese Patent Application Laid-Open No. 60-19157). (Japanese Patent Application Laid-Open No. 60-83038), the maximum potential of the charge for forming an electrostatic latent image in the image forming process is set to 400 to 700 V, and the latent image carrier and the developing sleeve are used. The minimum value of the gap between the surface area and the surface area is set within a range of 0.30 to 0.65 mm (Japanese Patent Publication No. 2-53782), and the absolute value of the potential contrast (difference between the dark part surface potential and the light part surface potential) is 400 V or less. In an electrostatic toner used in an electrostatic copying machine using a photoconductive photoreceptor, it has been proposed to add hydrophobic silica and conductive particles (Japanese Patent Application Laid-Open No. 2-126266). Image is to be obtained.

[0004]

However, according to these developers or image forming methods, it is not possible to obtain the image quality as intended by the present inventors. Accordingly, an object of the present invention is to provide an image forming method capable of obtaining a high image density even when the potential contrast is low, and a one-component or two-component developer useful for the method.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a low potential developing method and a developer suitable for the developing method, and as a result, the present invention has been accomplished. According to the present invention, first, in an image forming method for forming an electrostatic latent image on a latent image carrier, developing the electrostatic latent image in a developing area, transferring the electrostatic latent image to a transfer member, and fixing the same. The absolute value of the difference between the surface potential of the dark portion and the surface potential of the bright portion is 10
0 to 400 V, and the distance between the latent image carrier and the developer carrier in the development area is set in a range of 0.4 to 0.7 mm, and the toner and the coating layer are formed on the developer carrier. An image forming method is provided, comprising supplying a dry two-component developer comprising a carrier containing a high dielectric substance.

Second, in an image forming method for forming an electrostatic latent image on a latent image carrier and then developing the electrostatic latent image in a development area, the electrostatic latent image is formed by a surface potential of a dark portion and a bright portion. The absolute value of the difference between the latent image carrier and the developer carrier in the development area is 0.4 to 400 V.
When the electrostatic latent image is developed using a magnetic or non-magnetic component toner on the developer carrying member, a range of 0.7 mm is set via a toner layer regulating member on a toner conveying member. After the toner thin layer is formed, the toner is supplied to the latent image carrier, developed, transferred to a transfer member, and fixed, to provide an image forming method.

Third, in the above-mentioned first or second image forming method, the toners used are color toners A, B, C and D, which are different colors of yellow, magenta, cyan and black. A first electrostatic latent image is formed on an image carrier, developed with color toner A, and then the color toner A image is transferred to a transfer member, and then the latent image carrier or another latent image is developed. Forming a second electrostatic latent image on the carrier;
After developing this with the color toner B, the color toner B image is superimposed and transferred onto the transfer member, and then a third electrostatic latent image is formed on the latent image carrier or another latent image carrier. Is formed and developed with the color toner C.
The image is superimposed on the transfer member and transferred, and then a fourth electrostatic latent image is formed on the latent image carrier or still another latent image carrier, and after developing this with the color toner D, A color image forming method is provided, wherein a color toner D image is superimposedly transferred onto the transfer member, and subsequently, the color toner image on the transfer member is fixed.

Fourthly, in the first or second image forming method, the toners used are color toners A, B, C and D, which are different from each other in yellow, magenta, cyan and black colors. A first electrostatic latent image is formed on an image carrier, developed with a color toner A, the color toner A image is transferred to an intermediate transfer member, and then the latent image carrier or another latent image is developed. After forming a second electrostatic latent image on the image carrier and developing it with color toner B, the color toner B image is superimposed and transferred to the intermediate transfer member, and then the latent image carrier or A third electrostatic latent image is formed on another latent image carrier, developed with a color toner C, and the color toner C image is transferred onto the intermediate transfer member by superimposition. Forming a fourth electrostatic latent image on a body or still another latent image carrier, After the development with the toner D, the color toner D image is transferred onto the intermediate transfer member in a superimposed manner, and then the toner image superimposed and transferred on the intermediate transfer member is collectively transferred onto a transfer member for finally fixing the toner image. A color image forming method characterized by transferring and fixing the transferred image is provided.

Fifth, there is provided a two-component developer, wherein the toner used in the first, second, third or fourth image forming method contains a high dielectric substance. You. Sixth, the toner used in the first, second, third or fourth image forming method has a charge amount of ± 10 to 30 μc /
g, a two-component developer is provided.
Seventh, the degree of aggregation of the toner particles used in the first, second, third or fourth image forming method is set to 2 μm for sieves having openings of 75 μm, 45 μm and 22 μm arranged in series.
A one-component or two-component developer, wherein the value obtained by adding g toner is 15 or less.

Eighthly, the coating layer of the carrier used in the first, third or fourth image forming method is a silicone resin or a mixed resin of fluorine / styrene acrylic resin. A two-component developer is provided. Ninthly, there is provided a two-component developer used in the first, third or fourth image forming method or characterized in that a conductive material is dispersed in the coating layer of the eighth carrier. Is done. Tenthly, the first, third or fourth carrier particles used in the third or fourth image forming method, wherein the magnetic material is dispersed in a binder resin, or a conductive material is further dispersed therein. And a two-component developer comprising: Eleventh, the first, third or fourth image forming method or the eighth, ninth or tenth carrier has a volume resistivity of 10 ⁸ to 10 ¹⁴ Ωcm. Is provided.

Twelfth, in the two-component developer used in the first, third or fourth image forming method, the concentration of the toner particles is 1.5 to 10% by weight based on the carrier particles. A two-component developer is provided.

As described above, in the present invention, the development electric field is favorably maintained by including a high dielectric substance in the carrier coating layer. In addition, the above problem was solved by containing a high dielectric substance in the toner to maintain a good developing electric field. For this reason, according to the present invention, good image density (ID) is maintained, there is no background dirt or toner scattering even under high temperature and high humidity, and no decrease in ID occurs even under low temperature and low humidity. Further, even under these conditions, the toner is not stained on the photoconductor.

In the present invention, an image can be kept good by regulating the toner charge amount and toner concentration. Also,
By defining the toner cohesion degree, a good image without transfer omission is obtained. The agglomeration degree is an index indicating the adhesive strength between toners. If the value is large, the adhesive strength between toners is large and the developing flight property is deteriorated. Conversely, if the value is small, background dirt tends to occur. Therefore, in the toner of the present invention, sieves of 75 μm, 45 μm and 22 μm are arranged in series in that order, and the cohesion obtained when 2 g of toner is charged is in the range of 15, preferably 12 to 3. .

The degree of aggregation of the toner in the present invention is determined by using a powder tester (manufactured by Hosokawa Micron Co., Ltd.) and sifting sieves having openings of 75 μm, 45 μm, and 22 μm in this order from the top. And shake for 30 seconds at an amplitude of 1 mm. After the vibration, the weight of the toner on each sieve was measured.
It is calculated as a percentage by adding weights of 0.3 and 0.1.

Further, in the present invention, by providing a resin comprising a silicone resin or a mixed system of fluorine / styrene-acrylic resin in the carrier coating layer, it is possible to prevent toner from being spent and obtain a long-life developer. In addition, by adding a conductive material to the carrier coating layer, the carrier resistance can be freely controlled. Even if the thickness of the carrier coating layer is increased, a desired carrier resistance value can be easily obtained, and it is advantageous for film shaving. The Q / M level can be adjusted depending on the material to be added.

The volume resistivity of the carrier particles is 10 ⁸ -1.
0 ¹⁴ Ωcm is preferred. If it is more than 10 ¹⁴ Ωcm, the edge effect becomes large. On the other hand, when it is less than 10 ⁸ Ωcm, carrier adhesion is likely to occur. In particular, when the distance between the latent image carrier and the developing sleeve is set to 0.4 to 0.7 mm as in the process of the present invention, when the carrier resistance is set, the image quality is extremely improved. By providing a specific spacing between the latent image carrier and the developing sleeve, the electric field intensity formed in the developing area by the latent image increases,
As a result, by setting the above-mentioned carrier resistance, fine changes in gradation and fine patterns can be developed neatly.

The method of measuring the volume resistivity of the carrier particles is as follows. Area 10cm ² (length 4cm, width 2.5
cm) into a cell formed by opposing two electrode plates at an interval of 2 mm so that the sample overflows.
In this state, the tapping operation of dropping the sample from the position having a height of 15 mm onto the flat plate is repeated 30 times, and the sample is densely filled in the cell. Next, the excess sample on the cell is removed. Then, in this operation, a voltage corresponding to a DC electric field of 500 V / cm is applied to the electrode plate in an environment of 20 ° C. and 60% RH to determine the volume resistivity.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. In the first, third, and fourth methods of the present invention, a two-component developer composed of a toner and a carrier is used, and in the second method, a one-component developer is used. Alternatively, the carrier coating layer desirably contains a high dielectric substance. Specific examples of the high dielectric substance here include (i) a rossyl salt-based substance (Rochelle salt,
(Ii) Perovskite-based (barium titanate, lead titanate, sodium tantalate, lead zirconate titanate, etc.), (iii) Pyrochlorite-based (cadmium niobate, pyroniobate) (Iv), (iv) ilmenite type (cadmium titanate, iron titanate,
(V) guanidine-based (guanidine gallium sulfate,
Guanidine chromium sulfate etc.), (vi) glycine type (glycine sulfate, glycine silver sulfate etc.), (vi
i) Solid solution (lead titanate / lead zirconate, lead niobate /
(Viii) cyanoresin (ix) copolymer type (polyvinylidene fluoride-trifluoroethylene, polyvinylidene fluoride-tetrafluoroethylene, etc.).

The addition amount of these high dielectric substances is from 0.2 to 50% by weight, preferably from 0.3 to 35% by weight, based on the total weight of the toner, and is based on the carrier coating layer. Is from 0.1 to 40% by weight, preferably from 0.2 to 35% by weight, based on the total weight thereof.

The toner contains a binder resin, a colorant, and a charge control agent as main components, and further includes other additives as necessary. Specific examples of the binder resin include polystyrene, chloropolystyrene, poly-α-methylstyrene,
Styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid Ester copolymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic acid ester copolymer Merged (styrene-methyl methacrylate copolymer,
Styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-α-methyl methacrylate copolymer, styrene-acrylonitrile-acrylate copolymer Styrene-based resins such as coalesced polymers (mono- or copolymers containing styrene or styrene substituents), vinyl chloride resins, rosin-modified maleic resins, phenyl resins, epoxy resins, polyester resins, low molecular weight polyethylene, low molecular weight polypropylene, Ionomer resin,
Polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral, and the like can be used.

As the coloring materials (for example, yellow, magenta, cyan and black) used in the toner of the present invention, those known for toner can be used, and specific examples thereof include the following.

<Specific Examples of Yellow Colorant> CI Pigment Yellow 1 Symuler Fast Yellow GH (Dainippon Ink) 3 Symuler Fast Yellow 10GH (Dainippon Ink) 12 Symuler Fast Yellow GF (Dainippon Ink) 13 Symuler Fast Yellow GRF (Dainippon Ink) Dai Nippon Ink) 14 Symuler Fast Yellow 5GR (Dainippon Ink) 17 Symuler Fast Yellow 8GR (Dainippon Ink) 17 Lionol Yellow FGNT (Toyo Ink) Furthermore, as CI Pigment Yellow 12, Yellow 152 (Arimoto Chemical) Pigment Yellow GRT (Dai Nippon Kagaku) Sanyo Dye) Sumika Print Yellow ST-O (Sumitomo Chemical) Benzidine Yellow 1316 (Noma Chemical) Seika Fast Yellow 2300 (Dainichi Seika) Lionol Yellow GRT (Toyo Ink)

<Specific Examples of Magenta Colorant> CI Pigment Red 81 Symuler Rhodamine Y Toner F
(Dainippon Ink) CIPigment Red 122 Fastogen Super Magenta RE02
(Dainippon Ink) CIPigment Red 57 Symuler Brill Carmine LB (Dainippon Ink) CIPigment Red 22 Symuler Fast Brill Scarlet BG
(Dainippon Ink) CIPigment Red 21 Sanyo Fast Red GR (Sanyo Dye) CIPigment Red 18 Sanyo Toluidine Maroon Medium
(Sanyo Dye) CIPigment Red 114 Symuler Fast Carmine BS (Dainippon Ink) CIPigment Red 112 Symuler Fast Red FGR (Dainippon Ink) CIPigment Red 5 Symuler Fast Carmine FB (Dainippon Ink)

<Specific Examples of Cyan Colorant> CIPigment Blue 15 Fastogen Blue GS (Dainippon Ink) Chromofine SR (Dainichi Seika) CIPigment Blue 16 Sumitone Cyanine Blue LG (Sumitomo Chemical) CIPigment Green 7 Phthalogcyanine Green (Tokyo Ink) CIPigment Green 36 Cyanine Green 2 YL (Toyo Ink) CIPigment Blue 15: 3 Cyanine Blue GGK (Nippon Pigment) CIPigment Blue 15: 3 Lionol Blue FG7351 (Toyo Ink)

<Specific Examples of Black Colorant> Carbon Black Spirit Black Aniline Black (C.I. Pigment Black 1)

The amount of the colorant is 0.1 to 15 parts by weight, more preferably 0.15 to 9 parts by weight, per 100 parts by weight of the binder resin.
Parts by weight are appropriate.

Specific examples of the charge control agent include a nigrosine dye, a chromium-containing complex, a quaternary ammonium salt, and the like, which are used depending on the polarity of the toner particles. The amount of the charge control agent is 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight, based on 100 parts by weight of the binder resin.

In addition, it is advantageous to add a fluidity-imparting agent to the obtained toner particles. As the fluidity-imparting agent, silica, alumina, magnesia, zirconia, ferrite, fine particles of metal oxides such as magnetite and the fine particles, silane coupling agent, titanate coupling agent, zircoaluminate, quaternary ammonium salt,
Fatty acid, fatty acid metal salt, fluorine-based activator, solvent, surface-treated or coated with a treating agent such as polymer, stearic acid, fine particles of a fatty acid such as zinc stearate or a metal salt thereof, and the fine particles with the treating agent Surface-treated, polystyrene, polymethyl methacrylate, polymer fine particles such as polyvinylidene fluoride and those fine particles surface-treated or coated with the treating agent,
Are used. The particle size of these fluidity-imparting agents is 0.0
Those having a range of 1 to 3 μm are used.

The amount of the fluidity-imparting agent is preferably 0.1 to 7.0 parts by weight, more preferably 0.2 to 5.0 parts by weight, based on 100 parts by weight of the toner particles. The method of mixing the toner particles and the fluidity-imparting agent is such that the powder is moved at a high speed by a gas flow or a mechanical force in a fluidized state so that pulverization does not substantially occur. Examples of the mixer include a high-speed fluid mixer, such as a Henschel mixer and a UM mixer.

The method for producing the toner for a two-component developer according to the present invention can be produced by various known methods or a combination thereof. For example, in the kneading and pulverizing method, a binder and a coloring material such as carbon black and necessary additives are dry-mixed, heated and melt-kneaded with an extruder or a two-roll, three-roll, or the like, and then cooled and solidified. The toner is obtained by pulverizing with a pulverizer such as a jet mill and classifying with a pneumatic classifier. Further, a toner can be directly produced from a monomer, a colorant, and an additive by a suspension polymerization method or a non-aqueous dispersion polymerization method.

The carrier core material itself is used, or a carrier material provided with a coating layer on the core material is generally used. Ferrite and magnetite are used as the core material of the resin-coated carrier that can be used in the present invention. The particle size of the core material is suitably from 20 to 65 μm, preferably about 30 to 60 μm.

Examples of the fluorine-containing monomer used for forming the carrier coating layer include vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinyl ether having a fluorine atom, and fluorine atom having a fluorine atom. There is a vinyl ketone, such as vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, perfluoroalkyl vinyl ether-vinylidene fluoride-tetrafluoroethylene copolymer, Vinylidene fluoride polymer, tetrafluoroethylene copolymer,
There is a polymer containing a vinyl ether substituted with a fluorine atom, a polymer containing a vinyl ketone substituted with a fluorine atom, a fluorinated alkyl acrylate polymer or a fluorinated alkyl methacrylate polymer.

The components copolymerized with the fluorine-containing monomer include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, acrylic acid, methacrylic acid,
Methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, benzyl acrylate, benzyl methacrylate, acrylamide, methacrylamide, cyclohexyl acrylate, cyclohexyl methacrylate, hydroxyethyl acrylate, glycidyl acrylate, methacryl Glycidyl acid, vinyl acetate, ethylene, propylene and the like.

The above polymer and copolymer can be used alone as a coating material, but may contain other resin components.
Other resin components include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate,
Butyl acrylate, butyl methacrylate, benzyl acrylate, benzyl methacrylate, acrylamide, methacrylamide, cyclohexyl acrylate, cyclohexyl methacrylate, hydroxyethyl acrylate,
There is a polymer of hydroxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, or a copolymer polymerized from any two or more monomers.

Commercially available silicone resins (straight silicone resins) used for forming the carrier coating layer include KR271 and KR251 manufactured by Shin-Etsu Chemical Co., Ltd., SR2400 and SR2406 manufactured by Toray Silicon Co., Ltd., and modified silicone resins. KR manufactured by Shin-Etsu Chemical Co., Ltd.
No. 206 (modified alkyd resin), KR3093 (modified acrylic resin), ES1001N (modified epoxy resin), SR2115 (modified epoxy resin), SR21109 (modified alkyd resin), and the like. The amount of the release resin used is suitably about 0.5 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, per 100 parts by weight of the carrier core material.

Specific examples of the conductive material include the following. (1) Example of white conductive material: ETC-50 (TiO ₂ type)
KV400 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd., ECR-72 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd., 5
00W (TiO ₂ system), manufactured by Ishihara Sangyo Co., Ltd., 300 W (TiO ₂
System) manufactured by Ishihara Sangyo Co., Ltd., S-1 (TiO ₂ system) manufactured by Ishihara Sangyo Co., Ltd., W-1 (SnO ₂ system) manufactured by Mitsubishi Metal Corporation, 23K (Zn
O) Conductive zinc white No. 1 (ZnO) manufactured by Honjo Chemical Co., Ltd. 2 (ZnO) manufactured by Honjo Chemical Co., Ltd., W-10 (TiO ₂ system) manufactured by Mitsubishi Metal Corporation,
DENTOL WK-100 (conductive fiber) manufactured by Otsuka Chemical Co., Ltd.
DENTOL WK-200 (conductive fiber) manufactured by Otsuka Chemical Co., Ltd.
DENTOL WK-300 (conductive fiber) manufactured by Otsuka Chemical Co., Ltd.
MEC300 (SnO ₂ series) manufactured by Teikoku Chemical Industries, MEC50
0 (SnO ₂ series) manufactured by Teikoku Chemical Co., Ltd.

(2) Example of carbon: Black Pea
rls 2000, VULCANXC-72 (Cabot), Ketjen black EC-DJ500,
Ketchen black EC-DJ600 (manufactured by Lion Akzo), Denka black granular, Denka black
Powder (made by Denki Kagaku Kogyo Co., Ltd.), CONDUCTEX97
5, CONDUCTEX SC (manufactured by Columbia Carbon),

The amount of the conductive substance is 0.05 to 70 parts by weight, more preferably 0.1 to 50 parts by weight, based on 100 parts by weight of the silicone resin. If necessary, a silane coupling agent may be used to improve the adhesive strength of the coating layer or to improve the dispersibility of the conductive material, and, if necessary, to adjust the Q / M. May be added to the above-mentioned coat layer.

As a method of forming the coating layer, a resin may be applied to the surface of the carrier core particles by a spraying method, a dipping method, or the like, as in the related art.

In the present invention, by blending a resin comprising a silicone resin or a mixed system of fluorine / styrene-acrylic resin into the carrier coating layer, toner spent can be prevented and a long-life developer can be used. The carrier resistance can be freely controlled by adding a conductive material to the coating layer of the carrier. Even if the thickness of the carrier coating layer is increased, a desired carrier resistance value can be easily obtained, and it is advantageous for film shaving. In addition,
Depending on the material to be added, the Q / M level can also be adjusted.

In the method of the present invention, a magnetic one-component toner or a two-component developer, or a non-magnetic one-component toner can also be used.

The carrier here may be “magnetic material-dispersed carrier particles” in which a magnetic material is dispersed in a binder resin. In the case of magnetic material-dispersed carrier particles, as a binder resin, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene -Vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylate copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc., styrene-methacrylic ester copolymer (styrene-methyl methacrylate copolymer, styrene-methacrylic) Ethyl acrylate copolymer, styrene-butyl methacrylate copolymer Styrene resin such as styrene-acrylonitrile-acrylate copolymer (a homopolymer or copolymer containing styrene or a styrene substituent), vinyl chloride resin, rosin-modified maleic resin, phenyl resin, epoxy Resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene,
Ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin,
Polyvinyl butyral, silicone resin such as F20
0, F250, F300, R900, R902, R92
5, E500, E600, SH6018, DC6-22
30 (manufactured by Toray Dow Corning), KR271, KR255, and KR251 manufactured by Shin-Etsu Chemical Co., Ltd., SR2400, SR2406 manufactured by Toray Silicon Co., Ltd., and as a modified silicone resin, KR206 (Alkyd manufactured by Shin-Etsu Chemical Co., Ltd.) Modified resin), KR3093
(Modified acrylic resin), ES1001N (modified epoxy resin), SR2115 (modified epoxy resin), SR2110 (modified alkyd resin) manufactured by Toray Silicon Co., Ltd., and the like.

As the magnetic fine powder, any material exhibiting magnetic sensitivity can be used. Examples thereof include metals such as iron, nickel, and cobalt, metal oxides, and alloys. Frequently used materials include ferric oxide, iron sesquioxide, cobalt-doped iron oxide, ferrite, nickel fine powder, and the like. The magnetic fine powder may be a colored magnetic material depending on the case. The magnetic material-dispersed carrier particles may contain a conductive material dispersed therein.

As the one-component toner (non-magnetic or magnetic toner), a toner containing the above-mentioned high dielectric substance is preferably used. In order to perform development with this one-component toner, it is advantageous to use the developing device shown in FIG. The toner 6 stored in the toner tank 7 is forcibly brought to the sponge roller 4 by the stirring blade 5, and the toner 6 is supplied to the sponge roller 4. The toner 6 taken in by the sponge roller 4 is carried to the toner conveying member 2 by the rotation of the sponge roller 4 in the direction of the arrow, and is rubbed and electrostatically or physically attracted. It rotates strongly in the direction of the arrow, and a uniform thin toner layer is formed by the elastic blade 3 and is triboelectrically charged. Thereafter, the latent image is transported to the surface of the latent image carrier (photoconductor) 1 which is in contact with or in proximity to the toner transport member 2, and the latent image is developed (developed). The electrostatic latent image is applied to the photoconductor at 300 V DC.
After charging, image exposure is performed to form a latent image, which is subsequently developed. When an image is formed using one-component magnetic toner, a fixed magnet is built in the toner conveying member 2.

[0045]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. The parts here are based on weight.

Example 1 500 g of silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.) 12.5 g of high-purity barium titanate (HPBT-1, manufactured by Fuji Titanium Industry Co., Ltd.) 5 kg of a ferrite carrier having a particle size of 50 μm was added thereto and sprayed under heating at 80 ° C. while flowing to apply, thereby obtaining a carrier coated with a high dielectric substance.

On the other hand, a mixture of a formulation comprising 100 parts of polystyrene (D-125, manufactured by Esso), 5 parts of a metal-containing dye (Spiron Black BH, manufactured by Hodogaya Chemical Co., Ltd.) and 10 parts of carbon black (manufactured by Mitsubishi Kasei Co., Ltd.) The mixture was kneaded under heating on two rolls, cooled and then pulverized and classified to obtain a black toner having a particle size of 5 to 20 μm. Silica (R97)
2, manufactured by Nippon Aerosil Co., Ltd.) in an external proportion of 0.6 parts.

A two-component developer was prepared by mixing 5 parts of the toner and 95 parts of the carrier. An electrophotographic copying machine (IMAZIO DA355, manufactured by Ricoh Co., Ltd.) was modified from this dry two-component developer to make the latent image potential 300 V, and the distance between the latent image carrier and the developer carrier to 0.5 ± 0.03 μm. The above developer was set in the prototype machine, and 100,000 copies were made by repeating charging, exposing, developing, transferring, and discharging 30 times a minute, an image was formed, and the image density was measured. However, the image density (ID) at the start is ID = 1.8.
The image density after copying 100,000 times is ID = 1.80.
High image density, fine line reproducibility, solid part reproducibility,
Good results were obtained for both halftone reproducibility. Here, the image density is measured by RD514 (Macbeth densitometer) (the same applies hereinafter).

Example 2 500 g of silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.) 12.5 g of high-purity barium titanate (HPBT-1, manufactured by Fuji Titanium Industry Co., Ltd.) 5 kg of a ferrite carrier having a particle size of 50 μm was added thereto and sprayed under heating at 80 ° C. while flowing to apply, thereby obtaining a carrier coated with a high dielectric substance.

On the other hand, a mixture of a formulation consisting of 80 parts of a styrene-n-butyl methacrylate copolymer, 10 parts of carbon black, and 10 parts of high-purity barium titanate was kneaded on a two-roll mill under heating, cooled, pulverized and classified. A black toner having a particle size of 5 to 20 μm was obtained. Silica (R97)
2, manufactured by Nippon Aerosil Co., Ltd.) in an external proportion of 0.6 parts.

A two-component developer was prepared by mixing 5 parts of the toner and 95 parts of the carrier. Imagio DA355 (manufactured by Ricoh Company) was modified from this dry two-component developer,
The developer was set on a prototype machine in which the latent image potential was set to 300 V and the distance between the latent image carrier and the developer carrier was 0.4 ± 0.03 mm, and an image was formed in the same manner as in Example 1. As a result, the image density at the start was ID = 1.85, and the image density after copying 100,000 times was as high as ID = 1.78, which was a good result with almost no change in image quality. was gotten.

Example 3 A solution having a composition consisting of 500 g of a silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.), 17.5 g of high-purity barium titanate, and 1430 g of toluene was coated on a ferrite carrier having a particle size of 50 μm using a fluidized bed type coating apparatus. 5 kg of the mixture was sprayed under heating at 80 ° C. while flowing to apply, and a carrier coated with a high dielectric substance was obtained.

On the other hand, a mixture of the above formulation comprising 75 parts of polyester resin, 10 parts of carbon black, and 15 parts of fine lead zirconate titanate ceramic powder was kneaded under heating on a two-roll mill, cooled, pulverized and classified to obtain a particle size of 5 to 20 μm. Black toner was obtained. For 100 parts of the toner, silica (R
972, manufactured by Nippon Aerosil Co., Ltd.) in an amount of 0.6 part.

5 parts of the toner and 95 parts of the carrier were mixed to prepare a two-component developer. Imagio DA355 (manufactured by Ricoh Company) was modified from this dry two-component developer,
The above developer was set on a prototype machine in which the latent image potential was set to 300 V and the distance between the latent image carrier and the developer carrier was set to 0.6 ± 0.03 mm, and an image was formed in the same manner as in Example 1. As a result, the image density at the start was ID = 1.88, and the image density after 100,000 copies was as high as ID = 1.84, and the image quality was almost unchanged. was gotten.

Example 4 Silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.) 500 g High-purity barium titanate 17.0 g Titanium oxide (ETC-52, manufactured by Titanium Industry Co., Ltd.) 0.5 g Flow of a solution having a composition of 1430 g of toluene Using a floor-type coating apparatus, 5 kg of a ferrite carrier having a particle size of 50 μm was put therein, sprayed under heating at 80 ° C. while flowing, and coated to obtain a carrier coated with a high dielectric substance. When the resistance of this carrier was measured, it was 1.2 × 10 ⁸ Ωcm.

On the other hand, a mixture of a formulation consisting of 75 parts of a polyester resin, 10 parts of carbon black, and 15 parts of high-purity barium titanate was kneaded under heating on a two-roll mill, cooled, pulverized and classified to obtain a black powder having a particle size of 5 to 20 μm. A toner was obtained. Silica (R97)
2, manufactured by Nippon Aerosil Co., Ltd.) in an external proportion of 0.6 parts.

5 parts of the toner and 95 parts of the carrier were mixed to prepare a two-component developer. Imagio DA355 (manufactured by Ricoh Company) was modified from this dry two-component developer,
The developer was set in a prototype machine in which the latent image potential was set to 250 V and the distance between the latent image carrier and the developer carrier was 0.7 ± 0.03 mm, and an image was formed in the same manner as in Example 1. As a result, the image density at the start was ID = 1.94, and the image density after copying 100,000 times was as high as ID = 1.87. When the resistance of the carrier was measured, the resistance at the start was 1.0 × 10 ⁸ Ωcm,
The resistance after copying 100,000 times was almost unchanged at 0.93 × 10 ⁸ Ωcm. When the Q / M was measured, the Q / M at the start was −24 μC / g, and the Q / M after 100,000 copies was −22 μC / g. A good result was obtained with almost no change.

Example 5 A solution having a composition consisting of 500 g of a silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.), 16.0 g of high-purity barium titanate, 1.5 g of titanium oxide (ETC-52, manufactured by Titanium Industry Co., Ltd.) and 1,430 g of toluene Using a floor-type coating apparatus, 5 kg of a ferrite carrier having a particle size of 50 μm was put and sprayed under heating at 80 ° C. while flowing to apply, thereby obtaining a carrier coated with a high dielectric substance. The measured resistance of the carrier was 2.6 × 10 ⁹ Ωcm.

On the other hand, a mixture of 80 parts of styrene-n-butyl methacrylate copolymer, 10 parts of carbon black, and 10 parts of high-purity barium titanate was kneaded on a two-roll mill under heating, cooled, pulverized and classified. A black toner of 5 to 20 μm was obtained. Silica (R972,
Nippon Aerosil Co., Ltd.) was added externally at a ratio of 0.6 part.

A two-component developer was prepared by mixing 5 parts of the toner and 95 parts of the carrier. Imagio DA355 (manufactured by Ricoh Company) was modified from this dry two-component developer,
The above developer was set on a prototype machine in which the latent image potential was set to 350 V and the distance between the latent image carrier and the developer carrier was 0.5 ± 0.03 mm, and an image was formed in the same manner as in Example 1. As a result, the image density at the start was ID = 1.93, and the image density after copying 100,000 times was as high as ID = 1.89. When the resistance of the carrier was measured, the resistance at the start was 2.03 × 10 ⁹ Ωm,
The resistance after copying 100,000 times was almost unchanged at 1.86 × 10 ⁹ Ωcm. When the Q / M was measured, the Q / M at the start was −22 μC / g, the Q / M after copying 100,000 times was −20 μC / g, no decrease in Q / M was observed, and the image quality was low. A good result was obtained with almost no change.

Example 6 Vinylidene fluoride-tetrafluoroethylene copolymer 15 g (VT-100, manufactured by Daikin Industries, Ltd.) Styrene-2-etherhexyl methacrylate-n-butyl acrylate copolymer 15 g High-purity barium titanate 5 g (HPBT-1, manufactured by Fuji Titanium Industry Co., Ltd.) A solution having a composition consisting of 1000 g of methyl ethyl ketone was coated with 5 kg of a ferrite carrier having a particle size of 50 μm using a fluidized bed type coating apparatus while flowing, and coated with a baking furnace at 130 ° C. The mixture was heated for 30 minutes and allowed to cool at room temperature. After cooling, the baking oven at 80 ° C again
After heating for a minute and cooling at room temperature, a carrier coated with a high dielectric substance was obtained.

On the other hand, a mixture consisting of 80 parts of styrene-n-butyl methacrylate copolymer, 10 parts of carbon black, and 10 parts of high-purity barium titanate was kneaded on a two-roll mill under heating, cooled, pulverized and classified. A black toner of 5 to 20 μm was obtained. Silica (R972,
Nippon Aerosil Co., Ltd.) was added externally at a ratio of 0.6 part.

A two-component developer was prepared by mixing 5 parts of the toner and 95 parts of the carrier. Imagio DA355 (manufactured by Ricoh Company) was modified from this dry two-component developer,
The developer was set in a machine in which the latent image potential was set to 300 V and the distance between the latent image carrier and the developer carrier was 0.4 ± 0.03 mm. However, the image density at the start is ID = 1.86, and the image density after 100,000 times copying is ID = 1.82, which is a high image density. Obtained.

Example 7 A fluidized bed type coating apparatus was prepared by applying a solution having a composition consisting of 500 g of silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.), 12.5 g of high-purity barium titanate (HPBT-1, manufactured by Fuji Titanium Industry Co., Ltd.), and 1450 g of toluene. 5 kg of a ferrite carrier having a particle size of 50 μm was added thereto and sprayed under heating at 80 ° C. while flowing to apply, thereby obtaining a carrier coated with a high dielectric substance.

On the other hand, a mixture of 100 parts of polystyrene (D-125, manufactured by Esso), 5 parts of metal-containing dye (Spiron Black BH, manufactured by Hodogaya Chemical Co., Ltd.) and 10 parts of carbon black (manufactured by Mitsubishi Kasei Co., Ltd.) The mixture was kneaded under heating on two rolls, cooled and then pulverized and classified to obtain a black toner having a particle size of 5 to 20 μm. Silica (R97)
2, manufactured by Nippon Aerosil Co., Ltd.) in an external proportion of 0.6 parts.

A two-component developer was prepared by mixing 5 parts of the toner and 95 parts of the carrier. Imagio DA355 (manufactured by Ricoh Co., Ltd.) was modified from a dry two-component developer to a latent image potential of 100 V, and the distance between the latent image carrier and the developer carrier was set to 0.5 ± 0.03 mm. The above developer was set, and 100,000 copies were made by repeating charging, exposure, development, transfer, and charge elimination 30 times a minute, an image was formed, and the image density was measured. The density was ID = 1.83, and the image density after 100,000 copies was ID = 1.79. A high image density was obtained, and excellent results were obtained in fine line reproducibility, solid portion reproducibility, and halftone reproducibility. became.

Comparative Example 1 A test was performed in the same manner as in Example 1 except that high-purity barium titanate was omitted from the composition of the carrier of Example 1. As a result, the image density ID at the start was 1.10.
The image density ID after image copying was as low as 0.52, and an edge effect occurred.

Comparative Example 2 A test was conducted in the same manner as in Example 2 except that high-purity barium titanate was removed from the carrier composition of Example 2 and high-purity barium titanate was removed from the toner composition.
The image density ID at the start was 1.15, the image density ID after copying 100,000 times was as low as 0.56, and the image was blurred.

Comparative Example 3 A test was performed in the same manner as in Example 3 except that the silicone resin liquid was changed to a methyl methacrylate copolymer from the composition of the carrier in Example 3, and sprayed under heating at 50 ° C. The image density ID at the start is 1.51, and 1
An image density of ID = 0.95 was obtained after copying 100,000 times. When the Q / M was measured, the Q / M at the start was −23 μC / g, and the Q / M was 100,000 times after copying. /
M became -5 μC / g, and Q / M decreased. When the surface of the carrier was viewed with an electron microscope, the toner was found to have adhered. In the image, an edge effect was generated, and the toner was scattered in the apparatus.

Comparative Example 4 The amount of the silicone resin in the carrier composition of Example 1 was 500
A carrier was prepared in the same manner as in Example 1 except that g was changed to 20 g. The measured fixed volume resistance of the carrier was 7.12 × 10 ⁷ Ωcm. Using the carrier, a developer was prepared in the same manner as in Example 1,
When image output was performed, the image density was ID = 1.85.
Although the image density was high, carrier adhesion occurred and background contamination also occurred.

Comparative Example 5 The amount of silicone resin in the carrier composition of Example 1 was 500
A carrier was prepared in the same manner as in Example 1, except that the g was changed to 800 g. The measured resistance of the carrier was 5.81 × 10 ¹⁵ Ωcm. Using the carrier, a developer was prepared in the same manner as in Example 1, and an image was formed. As a result, the image density was ID = 1.10, but an edge effect occurred, and the trailing edge was blurred. Image became.

Examples 8 and 9, Comparative Example 6 Silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.) 500 g High-purity barium titanate 12.5 g (HPBT-1, manufactured by Fuji Titanium Industry Co., Ltd.) A solution having a composition of 1450 g of toluene Using a fluidized bed type coating apparatus, 5 kg of a ferrite carrier having a particle size of 50 μm was put therein, sprinkled with heating at 80 ° C. while flowing, and coated to obtain a carrier coated with a high dielectric substance.

The toner was prepared as follows. Styrene-n-butyl methacrylate copolymer 80 parts Carbon black 10 parts High purity barium titanate 10 parts A mixture of the formulation consisting of kneading on a two-roll mill with heating, cooling, pulverization and classification, particle size 5 to 20 μm Black toner was obtained. Silica (R97)
2, manufactured by Nippon Aerosil Co., Ltd.) and the degree of aggregation was changed by changing the amount as shown in the following table (Table 1).

A two-component developer was prepared by mixing 5 parts of the toner and 95 parts of the carrier. Imagio DA355 (manufactured by Ricoh Company) was modified from this dry two-component developer,
The developer was set on a prototype machine in which the latent image potential was set to 300 V and the distance between the latent image carrier and the developer carrier was 0.4 ± 0.03 mm, and an image was formed in the same manner as in Example 1. did. In Examples 8 and 9, a good image was obtained from the start, and the image after 100,000 times did not change at all from the start. On the other hand, Comparative Example 6 was inferior in image quality because the toner in the character portion was missing from the start (transfer missing).

Example 10 A non-magnetic one-component toner was prepared according to the following method. Particle A was prepared from the following composition. Styrene-2-ethylhexyl acrylate copolymer 100 parts Polypropylene 5 parts Barium titanate 12.5 parts Carbon black 7 parts Charge control agent (Zn salicylate) 3 parts The mixture consisting of heat was kneaded, crushed and classified to 8.5 μm.
Was obtained. Then, 0.5 parts of silica was mixed with 100 parts of the particles A to prepare a non-magnetic one-component toner. The non-magnetic one-component toner was put into the developing device shown in FIG. 1 and a continuous test was performed. As a result, a good image was obtained. The image quality did not change even after outputting the image after 50,000 sheets.

Example 11 A magnetic one-component toner was prepared according to the following method. Particle B was prepared from the following composition. Styrene-2-ethylhexyl acrylate copolymer 100 parts Polypropylene 5 parts Barium titanate 12.5 parts Magnetic material (EPT1000, manufactured by Toda Kogyo Co., Ltd.) 50 parts Charge control agent (chromium-containing monoazo dye) 3 parts And crush and classify to 8.5 μm
Was obtained. Then, the mixture was mixed at a ratio of 0.5 part of silica to 100 parts of the particle B to prepare a magnetic one-component toner. This magnetic one-component toner is put into the developing device shown in FIG.
When a continuous test was performed, good images were obtained.
The image quality did not change even after outputting the image after 50,000 sheets. Note that a fixed magnet is built in the toner conveying member 2 in FIG.

Comparative Examples 7 and 8 Toners were prepared in the same manner as in Examples 10 and 11, except that barium titanate was used in Examples 10 and 11, respectively, and tested. As a result, the image density was low, and thin lines were not significantly blurred. Was.

Example 12 A magnetic material-dispersed carrier was prepared as follows. Styrene / n-butyl methacrylate (70:30) 100 parts Copolymer Barium titanate 12.5 parts Magnetic material (EPT1000, manufactured by Toda Kogyo Co., Ltd.) 70 parts After melt-kneading the above with two rolls, a 40 μm carrier was added. Obtained. A developer was prepared in the same manner as in Example 1 using the toner of Example 1, and the same test was performed as in Example 1. As a result, similar results were obtained.

Examples 13 and 14 A developer was prepared and tested in the same manner as in Example 12, except that 100 parts of a silicone resin or vinylidene fluoride / styrene-methacrylate resin was used instead of styrene / n-butyl methacrylate. However, the same result as in Example 12 was obtained.

Comparative Example 9 A developer was prepared and tested in the same manner as in Example 12 except that barium titanate was omitted. As a result, the image density was low, and fine line blurring occurred.

Examples 15 and 16 and Comparative Examples 10 and 11 The Q / M was changed by changing the metal-containing dye in the toner of Example 1 as shown in the following table (Table 2). In Examples 15 and 16, the same results as in Example 1 were obtained. In Comparative Example 10, since the Q / M was low, the toner was scattered a lot and the background was very dirty. In Comparative Example 11, since the Q / M was high, the image density was low, and the thin line blur was remarkable.

Example 17 A color toner was prepared according to the toner formulation shown in the following table (Table 3).

For the production method of each toner, each formulation is preliminarily mixed with a mixer. Thereafter, the mixture is melt-kneaded three times with a three-roll mill, cooled, and then roughly pulverized to about 1 to 2.5 mm. Next, the mixture was finely pulverized by an air jet method, and then classified again to obtain a 7.0 μm toner.
R972 was added to 100 parts of each toner as a fluidity improver.
Silica (manufactured by Nippon Aerosil Co., Ltd.) was externally added at a ratio of 0.65 parts to obtain color toners of each color.

The carrier particles were prepared as follows. Silicone resin liquid (SR2406, manufactured by Toray Silicone Co., Ltd.) 500 g High-purity barium titanate 12.5 g (HPBT-1, manufactured by Fuji Titanium Co., Ltd.) A solution having a composition of 1450 g of toluene was subjected to particle size analysis using a fluidized bed type coating apparatus. 5 kg of a 50 μm ferrite carrier was put therein, sprayed under heating at 80 ° C. while flowing, and coated to obtain a carrier coated with a high dielectric substance.

A two-component developer was prepared by mixing 5 parts of each toner color with the carrier so that the total amount was 100 parts. The above-mentioned developer was placed in a modified Pretail 500 (a color copier manufactured by Ricoh Co., Ltd.) identical to that of Example 1, and an image was taken out. After 50,000 copies were made, there was no background dirt, voids, edge effect, or roughness. There was no change at all. A similar test was carried out and modified in the same manner as in Example 1 to produce a Pretail 750 (manufactured by Ricoh, color copying machine). The same result as the Pretail 500 was obtained.

Examples 18 to 24 Tests were carried out in the same manner as in Example 1 except that the high dielectric substances were changed as shown in the following table (Table 4), and the same results as in Example 1 were obtained.

Example 25 A developer was prepared in the same manner as in Example 12, except that 4.5 parts of Ketjen black EC DJ600 (manufactured by Lion Aguso) was further added as a conductive material to the magnetic substance-dispersed carrier formulation of Example 12. As a result, the same result as in Example 12 was obtained.

Example 26 A toner was prepared by replacing the carbon black of Example 10 with the coloring material of Example 17 and tested. As a result, the same results as in Example 10 were obtained.

Example 27 A color toner was prepared according to the toner formulation shown in the following table.

For the production method of each toner, each formulation is preliminarily mixed with a mixer. Thereafter, the mixture is melt-kneaded three times with a three-row mill, cooled, and then coarsely ground to about 1 to 2.5 mm. Next, the mixture was finely pulverized by an air jet method, and then classified again to obtain a 7.0 μm toner. R972 (manufactured by Nippon Aerosil Co., Ltd.) silica was externally added as a fluidity improver to 100 parts of each toner at a ratio of 0.65 parts.
Each color toner was obtained. Using this non-magnetic one-component toner, the pre-tails 500 and 750 (manufactured by Ricoh, color copying machine) were modified so as to enter the developing section in FIG. 1, and the copying process was further modified in the same manner as in Example 1. When a test was performed in the same manner as in Example 17, the same results as in Example 17 were obtained.

[0091]

According to the first and second aspects of the present invention, an electrostatic latent image obtained by using a low-potential-contrast photosensitive member can also be favorably formed. According to the third and fourth aspects of the present invention, a good full-color image can be obtained on the transfer member. Claims 5 to 12
According to the invention, a good quality carrier, a good toner or a good two-component developer can be obtained, so that a favorable image quality is guaranteed for a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating an example of a developing device using a one-component toner according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 latent image carrier 2 toner transport member 3 elastic blade 4 sponge roller 5 stirring blade 6 toner 7 toner tank

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location G03G 13/06 G03G 9/08 361 15/01 113 9/10 351 361 (72) Inventor Mitsuteru Kato Ricoh Co., Ltd. 1-3-6 Nakamagome, Ota-ku, Tokyo (72) Inventor Tomomi Suzuki Ricoh Co., Ltd. 1-3-6 Nakamagome, Ota-ku, Tokyo

Claims (12)

[Claims] 1. An image forming method comprising: forming an electrostatic latent image on a latent image carrier, developing the electrostatic latent image in a developing area, transferring the electrostatic latent image to a transfer member, and fixing the electrostatic latent image; The difference between the surface potential of the dark area and the surface potential of the light area is 100 to 100 in absolute value.
400 V, the distance between the latent image carrier and the developer carrier in the development area is set in a range of 0.4 to 0.7 mm,
An image forming method comprising: supplying a dry two-component developer comprising a toner and a carrier containing a high dielectric substance to a coating layer on the developer carrier. 2. An image forming method for forming an electrostatic latent image on a latent image carrier and then developing the electrostatic latent image in a developing area,
In the electrostatic latent image, the difference between the surface potential of the dark portion and the surface potential of the bright portion is 100 to 400 V in absolute value, and the distance between the latent image carrier and the developer carrier in the development area is set to 0.1. 4-0.7m
m, on the developer carrier, when developing the electrostatic latent image using a magnetic or non-magnetic component toner, the toner is regulated via a toner layer regulating member on a toner conveying member. An image forming method, comprising: after forming a thin layer, supplying the toner onto the latent image carrier, developing the toner, transferring the toner to a transfer member, and fixing the toner. 3. The image forming method according to claim 1, wherein the toners used are color toners A, B, C, and D.
These are different from each other yellow, magenta, cyan,
A first electrostatic latent image formed of a black color on a latent image carrier, developed with a color toner A, and then the color toner A image is transferred to a transfer member; After forming a second electrostatic latent image on a carrier or another latent image carrier and developing it with color toner B, the color toner B image is transferred onto the transfer member in an overlapping manner. Forming a third electrostatic latent image on the latent image carrier or another latent image carrier, developing the third electrostatic latent image with color toner C, transferring the color toner C image on the transfer member in a superimposed manner, Next, a fourth electrostatic latent image is formed on the latent image carrier or another latent image carrier, developed with a color toner D, and the color toner D image is superimposed on the transfer member. Transferring, and subsequently fixing the color toner image on the transfer member. 4. The image forming method according to claim 1, wherein the toners used are color toners A, B, C and D.
These are different from each other yellow, magenta, cyan,
A first electrostatic latent image of black color is formed on a latent image carrier, developed with a color toner A, and then transferred to the intermediate transfer member. Forming a second electrostatic latent image on the image carrier or other latent image carrier,
After developing this with the color toner B, the color toner B image is overlaid and transferred onto the intermediate transfer member, and then a third electrostatic latent image is formed on the latent image carrier or another latent image carrier. Forming
After developing this with the color toner C, the color toner C image is overlaid and transferred onto the intermediate transfer member, and then a fourth electrostatic latent image is formed on the latent image carrier or another latent image carrier. Forming
After developing this with the color toner D, the color toner D image is superimposed and transferred to the intermediate transfer member, and then the color toner image superimposed and transferred onto the intermediate transfer member is collectively transferred to the transfer member. Fixing a color image. 5. A two-component developer, wherein the toner used in the image forming method according to claim 1 contains a high dielectric substance. 6. The toner according to claim 1, wherein the charge amount of the toner is ± 10 to 30 μc / g.
A two-component developer, characterized in that: 7. A sieve having an agglomeration degree of 75 μm, 45 μm and 22 μm of meshes arranged in series, wherein the toner particles used in the image forming method according to claim 1 are 2
A one- or two-component developer, wherein the value obtained by adding g of toner is 15 or less. 8. The carrier coating layer used in the image forming method according to claim 1, wherein the coating layer is a silicone resin,
Or a two-component developer, which is a mixed resin of fluorine / styrene acrylic resin. 9. A two-component developer used in the image forming method according to claim 1, wherein the coating layer of the carrier contains a conductive material. . 10. The carrier particles used in the image forming method according to any one of claims 1, 3, and 4, wherein the carrier particles contain a magnetic material in a binder resin, or further include a conductive material. A two-component developer characterized by comprising: 11. A carrier used in the image forming method according to any one of claims 1, 3 and 4, or wherein the carrier has a volume resistivity of 10 ⁸ to 10 ¹⁴ Ωcm. Two-component developer. 12. The two-component developer used in the image forming method according to claim 1, wherein the concentration of the toner particles is 1.5 to 10% by weight based on the carrier particles. Characteristic two-component developer.