JPH01302268A - Method for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To enhance durability of an organic photosensitive body and to prevent deterioration of its sensitivity and fogging by using a developer containing fine inorganic particles with an antioxidant fixed to the surface. CONSTITUTION:The electrostatic charge image formed on the surface of the organic photosensitive body is developed by using the developer containing toner particles, the fine inorganic fine organic particles (B) with the antioxidant (A) fixed to its surface. A hindered phenol, such as 2,6-t-butyl-p-cresol, amine type antioxidants, and the like can be used for the antioxidant (A), and the particles (B) have an average particle diameter of, preferably, 0.01-2.0mum, and fine particles, such as silica and alumina, can be used for the particles (B), and fine hydrophobic inorganic particles can be added to the developer, and carrier particles can be added to form a binary developer.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the development integrity of an electrostatic image formed on the surface of an organic photoreceptor in electrophotography, electrostatic recording, electrostatic printing, etc. It is.

[Background of the invention]

As a conventional electrophotographic method, U.S. Patent No. 2,297,691
No. 2,357,809, etc.
An electrostatic latent image is formed on the surface of the photoreceptor, and the electrostatic latent image is made into a toner image using a dry developer made of colored fine powder.
After the toner image is transferred to a transfer sheet such as paper, it is permanently fixed by heating, pressure, etc. to form a copy image.

On the other hand, the electrostatic image bearing member is repeatedly subjected to removal of adhered toner, neutralization, and surface cleaning, and is used repeatedly over a long period of time.

Therefore, as an electrophotographic photoreceptor that carries an electrostatic image,
In addition to electrophotographic properties such as good charging characteristics and sensitivity, and low dark decay, physical properties such as printing durability after repeated use, abrasion resistance, and moisture resistance, as well as ozone generated during corona discharge, Oxidation resistance to ultraviolet rays, etc. during exposure (environmental resistance)
It is also required that the quality is good.

Conventionally, inorganic photoreceptors whose photosensitive layer is mainly composed of inorganic photoconductive substances such as selenium, zinc oxide, and cadmium sulfide have been widely used as electrophotographic photoreceptors. As a result, carrier generation and carrier transport functions are shared between different materials, and materials that exhibit each function are selected from a wide range according to the desired characteristics, and organic photoconductive semiconductors with high sensitivity and durability are used. Electrostatic image carriers (hereinafter referred to as photoreceptors) have been put into practical use.

Conventionally, such functionally divided organic photoreceptors have been mainly used for negative charging, and as described in JP-A No. 60-247647, a thin carrier generation layer is provided on a support.
A relatively thick carrier transport layer is provided on top of this.

However, in the above-mentioned negatively charging organic photoreceptor, a large amount of ozone is generated when negatively charged by a charger, which deteriorates the working environment and causes oxidation, which can cause deterioration of the photoconductive compound in the shallow layer on the surface of the organic photoreceptor. This may cause deterioration in the performance of the photoreceptor.

As mentioned above, the oxidation phenomenon impairs the properties of the photoreceptor and toner, and shortens their lifespan.The effect of the oxidation phenomenon is that over the duration of the copying operation, the characteristics of the photoreceptor made of an organic photoconductive semiconductor are deteriorated. Antioxidant measures to improve the durability of the body have become a particularly important issue.

To address the above-mentioned problem, for example, Japanese Patent Laid-Open No. 18366/1983 proposes incorporating an antioxidant into the constituent layers of a photoreceptor. However, in such a configuration, the antioxidant in the shallow layer on the surface of the photoreceptor, after exhibiting the effect of preventing carbonation, changes to another compound that does not have an antioxidant function and loses its function. Therefore, when considering long-term durability, although it is certainly effective in the very early stage, the antioxidant cannot be expected to be effective for a long period of time due to exhaustion of the antioxidant, and its durability is low. On the other hand, the remains of the antioxidant that has served as an antioxidant act as unnecessary impurities, and conversely impairs the performance of the organic photoreceptor, such as a decrease in sensitivity. Furthermore, in organic photoreceptors containing antioxidant residues, the antioxidant acts as an impurity, and the potential change gradient of the latent image in the boundary area between the image area and the non-image area becomes gentle, reducing the sharpness of the image. and resolution becomes lower.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a developing method in which the antioxidant effect on an organic photoreceptor is permanent, the durability of the organic photoreceptor is good, and there is no decrease in sensitivity and subsequent fogging.

Another object of the present invention is to provide a developing method that provides images with good sharpness and resolution over a large number of times.

[Means to achieve the purpose]

The object of the present invention is to develop an electrostatic image formed on the surface of an organic photoreceptor using a developer containing toner particles and inorganic fine particles having an antioxidant fixed to the surface. achieved.

In addition, in the aspect of the present invention, it is preferable that the average particle size of the inorganic fine particles is 0.01 to 2.0 μm.

[Function and effect of the invention]

In the present invention, the antioxidant is added to the developer in a state in which it is fixed to the surface of the inorganic fine particles, and the antioxidant is supplied to the surface of the organic photoreceptor during development.

The surface-treated inorganic fine particles have a smaller particle size and a larger van der Waals force than toner particles or carrier particles, so they have good adhesion to the surface of the photoreceptor. This effectively brings the antioxidant into contact with the surface of the photoreceptor and exerts an antioxidant effect.

The antioxidant is sequentially supplied from the developer, and also reduces the oxidation activity of the surface atmosphere of the organic photoreceptor, thereby preventing deterioration in the performance of the photoreceptor, such as fogging due to a decrease in sensitivity.

Furthermore, the altered substances of the antioxidant that have achieved the antioxidant effect are transferred to the transfer material as a toner image together with the toner particles, or even if they remain on the surface of the photoreceptor after transfer, they are removed during the process of cleaning the photoreceptor. It is removed by the blade and does not remain on the surface of the photoreceptor. Therefore, the durability of the organic photoreceptor can be significantly improved without adversely affecting the photoreceptor, and the antioxidant that has lost its antioxidant effect is gradually excreted out of the system, resulting in the aftereffects of adding the antioxidant. Therefore, the performance of the photoreceptor can be maximized without impairing the performance of the photoreceptor.

That is, the potential of the latent image in the boundary area between the image area and the non-image area changes sharply and clearly without being disturbed by oxide residues, and the sharpness, line image reproducibility, and resolution of the image can be significantly improved. can. Further, even when used many times, due to the action of the antioxidant supplied from the developer, there is no deterioration in performance, and the above effects can be maintained for a long period of time, resulting in excellent durability.

[Structure of the invention]

The present invention is preferably applied to a so-called brush development method in which an electrostatic charge image formed on the surface of an organic photoreceptor is developed by a brush-shaped developer made to stand on a developer carrier of a developing device.

The developer may be a one-component developer comprising toner particles and inorganic fine particles having an antioxidant fixed to the surface thereof, or a two-component developer further comprising carrier particles.

The inorganic fine particles having the antioxidant fixed to the surface thereof can be contained in a developer using a V-type mixer or the like, or in the case of a two-component developer using carrier particles, the inorganic fine particles can be mixed with the toner particles and the oxidation agent. Inorganic fine particles and carrier particles having an inhibitor fixed to their surfaces can be contained by a similar mixing method.

The average particle size of the inorganic fine particles on the surface of which the antioxidant used in the present invention is fixed is 0. O1 to 5.0 μm1 is preferably 0.05 to 2.0 μm; if it is too small, it may adhere too strongly to the surface of the photoreceptor, resulting in decreased performance of the photoreceptor or poor cleaning; on the other hand, if it is too large, This may result in a decrease in clarity and resolution.

Also, the amount added is 0 to 100 parts by weight of toner particles.
．． 001 to 3.0 parts by weight, preferably 0.001 to 3.0 parts by weight. O1~2.0
Parts by weight. If it is too small, the antioxidant effect will be small, and if it is too large, it may cause filming on the surface of the photoreceptor, resulting in a decrease in the performance of the photoreceptor.

Further, the melting point or freezing point of the antioxidant fixed to the surface of the inorganic fine particles is preferably 20 to 250°C, more preferably 50 to 150°C. 20
If the temperature is below 250°C, the storage stability of the toner will be poor, and if it exceeds 250°C, the offset resistance will deteriorate.

Specific examples of compounds from each prefecture selected as antioxidants according to the present invention will be listed, but the compounds are not limited to these examples. In addition, the melting point (-p) or freezing point (sp) is also written in parentheses as °C.

: Exemplary Compound: As the phenolic compound according to the present invention, hindered phenol is particularly preferred.

Next, specific examples of hindered phenols will be given, but the invention is not limited to these examples.

: Exemplary hindered phenol: Hl, mono-1-butyl-p-cresol (>49°,
5p) H2,mo/-1-butyl-cresol (
21', 5p) H3, butylhydroxyanisole (57-67°) H4, 2,6-di-t-butyl p
-cresol (69,9°)H5,2,6-di-t-
Butylphenol (37°) H6, 2,6-di-t-butyl-4-ethylphenol (〉43°) H7, 2,4,6-tri-t-butylphenol (1
31') H8,4-hydroxymethyl-2,6-di-t-butyl (140-141') H9, octadecyl-3-(4-hydroxy-3',
5'-di-t-butylphenyl) propionate
(49-52D) H10, distearyl (
4-Hydroxy-3-methyl-5-t-butyl)benzylmalonate (56-59,5°) H11,6-(4-hydroxy-3,5-di-t-butylanilino)2,4-bisoctylthio -1,3,5
-) Riazine (91-96°) Hl2.2
．． 6-diphenyl-4-octadekatsuki diphenol
(62-63') Hl3.4-t-butylcatechol (>5θ0) Hl4.2.5
-t-Butylhydroquinone (202°) Hl5.2.
5. Di-t-amylhydroquinone (>172°) H16, Propyl gallate (146-148
°)Hl7.4.4'-methylenebis(2,6-t-butylphenol) (>154')Hl
8.4.4″ Impropylidene bis(2,6-di-t-
butylphenol) (155-156°) 819
, 4,4'butylidene bis(3-methyl-6-[-pf
Lua / -4) (208-212')
H20,2,2'-methylenebis(4-methyl-6-butylphenol) (130~133°
)H21,2,2'-methylenebis(4-ethyl-6-
t-butylphenol) (>119°)
H22,2,2'-isobutylidene bis(4,6-dimethylphenol) (~160°)H23,2
,2'-dihydroxy3.3'-di(σ-methylcyclohexyl)-5,5'-dimethyldiphenylmethane (~130°)H24,2,2'-methylenebis(4-methyl-6-cyclohexylphenol) )(
≧180°) H2S, 2.6-bis(2″-hydroxy-3′-t-butyl-5′-methylbenzyl)4-
Methylphenol (171-172°
) H26, N, N'-hexamethylene bis(3,5-di-t-butyl-4-hydroxyhydrocinnamate) (156-1610) H27, hexamethylene glycol bis[β-(3,5
-di-t-butyl-4-hydroxyphenyl)propionate] (49-546)H2S, )lyethylene glycol bis[β-(3-t-butyl-5-methyl-
4-hydroxyphenyl)propionate] (76-7
9°) H29, Tris[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate (126-131') H2O, 1,3,5-tris(2,6 -cymethyl-3-
Hydroxy-4-t-butylbenzyl)in cyanurate (143°) H31,) lis (3
, 5-di-t-butyl-4-hydroxyphenol) isocyanurate (221°) H32
,1,1,3'-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane
(185-188°) H2S, Tetrakis[methylene-3-(3,5-di-1-/thi-4-hydroxyphenyl)propionate 1methane
25°) Next, amine compounds according to the present invention are illustrated.

: Exemplary amine antioxidant: A1. Phenyl-α-naphthylamine (>50”)A
2. Phenyl-β-naphthylamine (65°) A3
．． N,N'-diphenyl-p-phenyl diamine (>
140') A4. N-Phenyl-N'-isopropyl-p-7 22-diamine (>70°)A5.4.4'-
Tetramethyldiaminodiphenylmethane
(90°)A6. Aldol-α-7-tylamine (
powder) (>140°) A7. Aldol-α-naphthylamine (resin) (>6
0'') A 8 , 2.2.4-trimethyl-1,2-dihydroxyquinoline polymer (70°) Next, specific examples of the phosphorus antioxidant according to the present invention will be given.

: Exemplary phosphorus antioxidant: Pl, trilauryl phosphite (~20°
) P2. Trioctadecyl phosphite (~45°)
P3. Tristearylphosphite (~47°)P
4. diethyl ester ob-3,5-di-t-butyl-
4-Hydroxybenzylphosphoric acid (156-1616) P5
．． Tris(2,4-t-butylphenyl)phosphite (183°) P6. Tetra kiss (
2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite (75°) P7. Distearyl pentaerythritol diphosphite
(52°) P8. Bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite (179') P 9 , 9.10-Sibidro9-oxa-10-
Phospho-7enanthrene-l〇-oxide (115') PIO
,) Riphenylphosphine (81') Next, specific examples of the sulfur-based antioxidant according to the present invention will be given.

: Exemplary sulfur-containing compound: Sl, dilaurylthiodipionate (39,5-4
2.06) S2. Dimyristylthiodibropiotinite (49-54
°) S3. Lauryl stearyl thiodipropionate (55
~59°) S4. Distearylthiodipropionate (63,5~
68.5°) S5. Distearyl-β,β′-thiodibutyrate (4
1-45°) S6.3.3'-thiodipropionic acid (134
°)S7. Pentaerysphthol tetra(β-laurylthiopropionate) (45-46°): Exemplary sulfur-containing metal complexes: SC1, zinc diethyldithiocarbamate (175°) SC2, zinc dibutyldithiocarbamate (>103
°) SC3, nickel dibutyldithiocarbamate (>85
°) In the present invention, the oxidation is carried out by spraying a solution in which the antioxidant is dissolved or dispersed in a solvent onto the surface of the inorganic fine particles, or by immersing the inorganic fine particles in the solution and then removing the solvent by heating or the like. The inhibitor is fixed to the surface of the inorganic fine particles.

The antioxidant is 1 to 50% by volume based on the inorganic fine particles.
, preferably at a ratio of 5 to 40 vt%.

The inorganic fine particles that fix the antioxidant to the surface include silica, alumina, titanium oxide, barium titanate,
Examples include magnesium titanate, calcium titanate, strontium titanate, zinc oxide, cerium oxide, antimony trioxide, zirconium oxide, silicon carbide, and silicon nitride. Particularly preferred is fine silica powder, as it has excellent uniform dispersibility in the developer, provides good antioxidant effects, and stabilizes triboelectric charging properties.

The binder used in the present invention is preferably a non-linear polymer, and a vinyl-based non-linear polymer or a polyester-based non-linear polymer can be preferably used.

Further, the non-linear polymer has a glass transition point Tg of 4
Preferably it is 0 to 70''O.

The vinyl nonlinear polymer preferably used as the nonlinear polymer is a polymer or copolymer obtained by polymerizing or copolymerizing monomers having one or more vinyl groups. Yes, in order to make it a non-linear polymer, 2
A monomer having at least two vinyl groups may be used.

The vinyl nonlinear polymer is preferably a copolymer of a styrene monomer and an acrylic ester monomer and/or a methacrylic ester monomer.

Examples of the styrene monomer include styrene, 0
-Methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2
, 4-dimethylstyrene, p-butylstyrene, p-t
-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-denlestyrene, p-dodecylstyrene, p-methoxystyrene, p-
Examples include phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene.

In addition, examples of the acrylic ester monomer and/or methacrylic ester monomer include methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, and acrylic. lauryl acid, acrylic acid-2-
Ethylhexyl, stearyl acrylate, acrylic acid-
2-chloroethyl, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, methacrylic acid Examples include 2-ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylamineethyl methacrylate.

Furthermore, examples of monomers having two or more vinyl groups for nonlinearization include divinylbenzene, divinylnaphthalene, derivatives thereof, other aromatic divinyl compounds, ethylene glycol diacrylate, and ethylene glycol. Dimethacrylate, trimethylolpropane triacrylate, other acrylic esters or methacrylic esters having two or more double bonds,
Others can be mentioned. The amount of the monomer having two or more vinyl groups used is 0 to 0 based on the total amount of the monomer.
．． 01 to 20% by weight is preferred, particularly 0.1 to 10% by weight.

The polyester-based nonlinear polymer preferably used as the nonlinear polymer is obtained by condensation polymerization of a polyhydric alcohol monomer and a polyhydric carboxylic acid monomer, and the nonlinear polymer is trivalent or more. This is achieved by using a polyhydric alcohol monomer and/or a trihydric or higher polyhydric carboxylic acid monomer.

Examples of dihydric alcohol monomers that can be used to obtain the polyester nonlinear polymer include ethylene glycol, diethylene glycol, triethylene glycol, 1.2-7'robylene glycol,
．． Diols such as 3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1.4-butynediol, 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A1 hydrogenated bisphenol A1 polyoxyethylenated bis Examples include etherified bisphenols such as phenol A1 and polyoxypropylenated bisphenol A, and other dihydric alcohol monomers.

Examples of divalent carboxylic acid monomers that can be used to obtain the polyester nonlinear polymer include maleic acid, fumaric acid, mesaconic acid, citraconic acid,
itaconic acid, glutaconic acid, phthalic acid, isophthalic acid,
Terephthalic acid, cyclohexanedicarboxylic acid, succinic acid,
Examples include adipic acid, sepacic acid, malonic acid, anhydrides of these acids, dimers of lower alkyl esters and luic acid, and other divalent organic acid monomers.

In addition, examples of the trihydric or higher polyhydric alcohol monomers that can be used for nonlinearization include sorbitol, 1,2.3.6-hexanetetrol, 1,4-sorbitan, and pentaerythritol. , dipentaerythritol, tripentaerythritol, sucrose, 1.2.4-butanetriol, 1.2.5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, Mention may be made of trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and others.

In addition, examples of the trivalent or higher polyvalent carboxylic acid monomer that can be used for nonlinearization include 1.2.4-
Benzenetricarboxylic acid, 1.2.5-benzenetricarboxylic acid, 1.2.4-cyclohexanetricarboxylic acid, 2,5.7-naphthalenetricarboxylic acid, 112.4
・S7talenttricarboxylic acid, 1.2.4-butanetricarboxylic acid, 1.2.5-hexanetricarboxylic acid, 1
．． 3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxyl)methane, 1.2.7.8-octanetetracarboxylic acid, embol trimer acid, acid anhydrides thereof, and others. be able to.

In the formation of the polyester nonlinear polymer, 3
It is preferable that the monomer having a valence or higher value is contained in a proportion of 5 to 40 mol % of the monomer component as a structural unit in the nonlinear polymer.

The toner particles of the present invention may contain toner components such as a binder colorant, a charge control agent, a fixability improving agent, magnetic particles, and other property improving agents dispersed therein, if necessary.

As the colorant, all known colorants can be used, including dyes and pigments such as carbon black, benzidine yellow, quinacridone, rhodamine B, and 7-talocyanine blue.

Further, as the magnetic particles, a substance that is magnetized by being placed in a magnetic field is used, and examples thereof include powders of ferromagnetic metals such as iron, cobalt, and nickel, and compounds such as magnetite, maghematite, and ferrite. When iron oxide magnetic material is used as a colorant, 10 to 80 wt.
It is better to include %.

Further, the charge control agent used in the toner of the present invention includes:
Examples include metal complex dyes and nigrosine dyes.

Examples of the fixability improver contained in the toner of the present invention include polyolefins such as polyethylene and polypropylene, fatty acid esters and partially saponified fatty acid esters, polyhydric alcohol esters, paraffin waxes, silicone oils, aliphatic fluorocarbons, etc. can be used. By using such a fixing property improving agent, the mold release properties are improved and paper jams in the heat roller fixing device can be prevented.

To give an example of a preferred method for manufacturing the toner of the present invention, first, a binder resin to which toner components such as a colorant are added as necessary is melt-kneaded using, for example, an extruder, and after cooling, it is pulverized using a jet mill or the like. This is then classified to obtain toner with a desired particle size.

The toner of the present invention contains a hydrophobized inorganic material that further improves triboelectric charging properties and fluidity, improves developability and transferability, and helps uniformly disperse the antioxidant-adsorbed inorganic fine particles in the developer. A mixture of fine particles may be used.

The primary particle diameter of these hydrophobized inorganic fine particles is 5 mμ to 2 μm.
It is preferable that it is, and it is especially preferable that it is 5μ-500mμ.

In addition, the specific surface area according to the BET method is 20 to 500 i/g
It is preferable that The proportion of the hydrophobized inorganic fine particles used is preferably 0.01 to 5 wt%, particularly 0.01 to 2.0 wt% of the toner. Preferably, it is Ovt%. Specific examples of inorganic fine particles for hydrophobized inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, cerium oxide, antimony trioxide, and zirconium oxide. , silicon carbide, silicon nitride, etc. Particularly preferred is silica. Silane coupling agents are used as hydrophobizing agents for hydrophobization,
Silicone oils and silicon compounds such as polyorganosiloxane ammonium salts can be preferably used, and in particular, it is preferable that the hydrophobizing agent has an amino group or an ammonium base to improve charge build-up, stabilization of triangular charge, and environmental resistance. It is effective and has good durability.

As a method for fixing the toner of the present invention, a hot roller fixing method is preferred, in which the upper roller of the fixing roller is coated with a fluorine-based resin, and the lower roller is made of silicone rubber or a fluorine-based resin coated on silicone rubber. A relatively soft coated material is preferable in terms of fixing properties, anti-offset properties, prevention of paper jams, and durability of the roller.

The carrier particles used in the case of a two-component developer are preferably particles with an average particle size of 20 to 120 μm, and the magnetic particles include substances that are strongly magnetized in the direction of a magnetic field, such as iron, ferrite, and magnetite. Metals or alloys that exhibit ferromagnetism, such as iron, nickel, and cobalt, or compounds that contain these elements; alloys that do not contain ferromagnetic elements but become ferromagnetic through appropriate heat treatment, such as manganese- An alloy called a Heusler alloy such as copper-aluminum or manganese-copper-tin, or particles made of chromium dioxide or the like can be used. In addition, the surface of these particles is coated with styrene.
Acrylic resin, acrylic resin, silicone resin,
Coating with a fluorine-based resin or the like improves durability and triboelectric charging stability against environmental changes.

The organic photoreceptor according to the present invention is constructed by laminating an organic photoreceptor layer comprising, for example, an organic photoconductive substance dispersed in a binder resin on a conductive support made of aluminum, stainless steel, or the like.

For the organic photosensitive layer, carrier-generating substances that absorb light and generate charged carriers such as anthanthrone compounds, perylene derivatives, bisazo compounds, and phthalocyanine compounds, such as styrene, are used as organic photosensitive layers, especially from the viewpoint of increasing durability. - A carrier generation layer configured by being dispersed in a binder resin such as methyl methacrylate copolymer, polycarbonate resin, silicone resin, etc., and an oxadiazole derivative, triarylamine derivative, polyarylalkane derivative that transports the carrier, Preferably, a functionally separated photosensitive layer is formed by combining a carrier transport layer formed by dispersing a carrier transport substance such as a hydrazone derivative, a stilbene derivative, or a styryl triarylamine derivative in a binder resin similar to the above. From the viewpoint of wear resistance, use of polycarbonate resin further improves durability.

Next, the image forming process of the present invention will be explained.

FIG. 1 shows an example of an image forming apparatus that can be suitably used to carry out the developing method of the present invention.

Reference numeral 50 denotes an organic photoreceptor having an organic photoreceptor layer for forming an electrostatic latent image, and this organic photoreceptor 50 has a rotating drum shape. Around this latent image carrier 50, corona chargers 5 are arranged in order from the upstream side to the downstream side in the rotational direction.
1, an exposure optical system 52, a developing device 53, an electrostatic transfer device 54, a separator 55, and a blade type cleaning device 56 are arranged.

Reference numeral 70 denotes a contact heating type heat roller fixing device. A backup roller 72 is arranged to be in contact with the roller 71.

In the above-described apparatus, the surface of the organic photoreceptor 50 is charged to a -like potential by the corona charger 51, and then imagewise exposed by the exposure optical system 52, so that the developed surface of the photoreceptor 50 has a static image corresponding to the original. A charge image is formed. and developer 5
The electrostatic charge image is developed by a contact or non-contact magnetic brush development method using a developer containing antioxidant particles stored in 3 to form a toner image corresponding to the original.

This toner image is electrostatically transferred onto a transfer paper 40 by an electrostatic transfer device 54, and the toner image on the transfer paper 40 is heated and fixed by a heat roller fixing device 70 to form a fixed image. On the other hand, the surface of the organic photoreceptor 50 that has passed through the electrostatic transfer device 54 is rubbed by a blade-type cleaning device 56 to remove the toner remaining on the surface and restore the original clean surface. In addition, the corona charger 5 was
1, and then the next image forming step is carried out.

〔Example〕

Examples of the present invention will be specifically described below, but the present invention is not limited to these Examples.

(Manufacture of binder resin) (1) Binder A Polyoxypropylene (2,0)-2,2-bis(4-
Hydroxyphenyl)propane 378.5g (1,1
99.5 g (0.7 mol) of terephthalic acid were placed in a 4-hole round bottom flask of capacity IQ equipped with a thermometer, a stainless steel stirrer, a glass nitrogen inlet tube and a down-flow condenser. The flask was set on a mantle heater, nitrogen gas was introduced from the nitrogen gas introduction tube to raise the temperature while maintaining an inert atmosphere inside the flask, and then the temperature was raised to 0.
Add 5 g of diisopropyl orthostannate (catalyst),
Humidity 210'C! After the reaction was carried out while maintaining the temperature at
"Binder A" was obtained.

(2) Binder B Styrene 76.2 parts by weight α-methylstyrene 5 parts by weight Butyl acrylate 17 parts by weight Divinylbenzene 1.8 parts by weight Benzoyl peroxide 5 parts by weight Four units equipped with a stirrer, thermometer and nitrogen inlet tube 600 m of water containing 2 wt% tricalcium phosphate, Q, and 2 wt% sodium dodecylbenzenesulfonate was placed in a flask, and the inside of the reaction vessel was made into a nitrogen gas atmosphere via a nitrogen inlet tube, and 200 g of the above composition was added. was added under stirring at room temperature to suspend the mixture, and then the temperature was raised to 80°C and reacted for about 8 hours. After the reaction, the system is cooled, hydrochloric acid is added, filtration and washing are repeated to remove tricalcium phosphate and sodium dodecylbenzenesulfonate, and then dried to obtain a non-linear vinyl polymer. "Binder B" was obtained.

(Manufacture of toner particles) (1) Toner l 100 parts by weight of the above "binder A", 10 parts by weight of carbon black "Mogull LJ" (manufactured by Cabot Corporation), and charge control agent "Nigrosine SO" (manufactured by Orient Chemical Co., Ltd.) 2
parts by weight and 3 parts by weight of polypropylene "Viscol 66QPJ (manufactured by Kochu Kasei Kogyo Co., Ltd.) were mixed in a V-type blender, thoroughly melted and kneaded at 100 to 130°C with two rolls, then cooled, and then The powder was coarsely ground using a hammer mill, further finely ground using a jet mill, and then classified to produce Toner 1 having an average particle size of 11.0 μm.

(2) Toner 2 Toner 2 having an average particle size of 10.5 μm was produced in the same manner as in the production of Toner 1, except that 100 parts by weight of “binder B” was used instead of “binder A”.

(Production of hydrophobized inorganic fine particles) (1) Hydrophobized inorganic fine particles A-1 A polysiloxane having the ammonium salt shown below as a functional group as its constituent unit is dissolved in xylene,
A treatment solution was prepared.

(X is an integer) Next, silica fine particles "Aerosil 200J (manufactured by Nippon Aerosil Co., Ltd.) are placed in a mixer, and the above-mentioned polysiloxane is sprayed at a ratio of 5vt% to the silica fine particles. The solvent, xylene, was removed in a flask at a temperature of 200°C for 5 hours with stirring, thereby obtaining inorganic fine particles whose surface was treated with polysiloxane having an ammonium salt as a functional group. Hydrophobized inorganic fine particles A-IJ.The hydrophobized inorganic fine particles A-1 have an average primary particle diameter of 12 m.
The specific surface area measured by the μ and BET method was 115 m” and 7 g.

(2) Hydrophobized inorganic fine particles A-2 Silica fine particles "Aerosil 200J (manufactured by Nippon Aerosil Co., Ltd.) were placed in a closed Henschel mixer heated to 100°C, and amino group-containing silicone oil was added to the silica fine particles using isopropyl alcohol. (viscosity 1200 cps, amino equivalent 3500) was stirred at high speed while spraying at a rate such that the amino group-containing silicone oil was 2.Ovt%, and then heated at a temperature of 150 cps.
After drying at °C, hydrophobized inorganic fine particles whose surfaces were treated with amino group-containing silicone oil were obtained. This is referred to as "hydrophobized inorganic fine particles A-2." This hydrophobized inorganic fine particle A
-2 had an average primary particle diameter of 12 mμ and a specific surface area of 128 m''7g by the BET method.

(3) Hydrophobized inorganic fine particles A-3 Silica fine particles [Aerosil 300J (manufactured by Nippon Aerosil Co., Ltd.) were placed in a closed Henschel mixer heated to 70°C, and the silica fine particles were treated with an amino group-containing silane coupling agent. A solution of a certain γ-aminopropyltriethoxysilane dissolved in alcohol was stirred at high speed while being sprayed at a rate such that the amino group-containing silane coupling agent was 5.0% Ovt, and then heated at a temperature of 120%.
After drying at °C, inorganic fine particles whose surfaces were treated with an amino group-containing silane coupling agent were obtained. This is referred to as "hydrophobized inorganic fine particles A-3." This hydrophobized inorganic fine particle A-
No. 3 had an average primary particle diameter of 8 mμ and a specific surface area of 150 m"7g by the BET method.

(Production of inorganic fine particles with antioxidant fixed on the surface) (1) Inorganic fine particles B-1 Silica fine particles [Aerosil 200J (manufactured by Nippon Aerosil Co., Ltd.) were placed in a mixer, and after making an inert atmosphere with nitrogen, 2.6-di-t-butyl-p-cresol (mp, 69.9°C) 20vt% based on silica particles
After spraying a solution dispersed and dissolved in toluene at a ratio such that Inorganic fine particles surface-treated with an inhibitor were obtained. This is referred to as [Inorganic Fine Particles B-IJ].

The inorganic fine particles B-1 have an average primary particle diameter of 13 m.
The specific surface area measured by μ and BET method was 74 ra”7g.

(2) Inorganic fine particles B-2 Tetrakis [methylene-3-(3,5-di-t-
Butyl-4-hydroxyphenyl)propionate comethine (np, 110-125°O) 40 wt% was used, but in the same manner as inorganic fine particles B-1.
2” was obtained.

This inorganic fine particle B-,2 has an average primary particle diameter of 13
mμ, and the specific surface area measured by the BET method was 65 μ”/g.

(3) Inorganic fine particles B-3 Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.) was used instead of Aerosil 200, and tetrakis (2,4-di-t-t-butyl-p-cresol) was used instead of 2Qvt% of 2,6-di-t-butyl-p-cresol.
"Inorganic fine particles B-3" were obtained in the same manner as inorganic fine particles B-1, except that 30 wt% of -butylphenyl)-4,4'-biphenylene phosphomate (mp, 75°C) was used. The inorganic fine particles B-3 have an average primary particle diameter of 9+sμ,
The specific surface area determined by the BET method was 95 m''/g.

(Manufacture of carrier particles) (1) 8 parts by weight of carrier C1 silicone varnish RS R-2101J (manufactured by Le Silicone Co., Ltd.) was added using a fluidizing bed device.
10 of spherical copper-zinc ferrite particles (manufactured by Nippon Tetsuko Co., Ltd.)
0 parts by weight was spray coated and further heat treated at 200°C for 5 hours to sinter, and then the aggregates were sieved to produce a carrier having a coating layer made of silicone resin. This is referred to as "carrier CIJ. This carrier C1 has an average particle size of 86 μm.

(2) Carrier C2 Vinylidene fluoride-tetrafluoroethylene copolymer rVT-10
0J (copolymerization molar ratio -80: 20, intrinsic viscosity -〇,
95 dQ/g, manufactured by Daikin Industries, Ltd.) and 6 g of methyl methacrylate polymer "Acrivet MFJ (manufactured by Mitsubishi Rayon Co., Ltd.) were mixed in a mixed solvent of acetone and methyl ethyl ketone (mixed volume ratio -1: 1) 500 mol α. This coating solution was applied to 1 kg of magnetic particles made of spherical copper-zinc ferrite particles using a fluidizing bed device, and further heated at 200°C for 5 hours. After heat treatment, the aggregates were sieved to produce a carrier having a coating layer made of fluororesin.This carrier was designated as "Carrier C2J".The carrier C2 had an average particle size of 82 .mu.m.

(3) Carrier C3 (n represents an integer) A coating liquid was prepared by dissolving 15 g of the above polymer in a mixed solvent of acetone and methyl ethyl ketone (mixed volume ratio -1: l) of 500 mol. The coating liquid was coated on 1 kg of magnetic particles made of spherical copper-zinc ferrite particles using a fluidizing bed device, further heat-treated at 200°C for 5 hours, and then the aggregates were sieved. A carrier having a coating layer made of a fluorine-based resin was manufactured. This will be referred to as "carrier C3." This carrier C3 has an average particle size of 80 μm.

(Manufacture of developer) In each developer, the combinations of hydrophobized inorganic fine particles, antioxidant-treated inorganic fine particles, toner particles, and carrier particles shown in Table 1 below are used, and the antioxidant is first fixed on the surface of the toner. The antioxidant-treated inorganic particles and the hydrophobized inorganic particles are added to the surface of the toner particles by adding the inorganic particles and the hydrophobized inorganic particles from the outside and mixing them using a Henschel mixer. Each developer was manufactured by mixing the particles.

(Organic photoreceptor) (1) OP C1 A conductive support made of an aluminum cylinder, and a thickness made of vinyl chloride-vinyl acetate-maleic anhydride copolymer (S-LEC MF-10, manufactured by Tsukizui Kagaku Kogyo Co., Ltd.) 0.
A 1 μm intermediate layer was formed.

Next, a carrier transport substance [styryl compound: structural formula (1
))/Polycarbonate resin (Panlite L-1250
, manufactured by Ryotaikasei Co., Ltd.) = 75/100 (weight ratio) to 16.
A 1,2-dichloroethane solution containing 5 vt% was dip-coated onto the intermediate layer and dried to obtain a carrier transport layer with a thickness of 15 μm.

Then, 4,10-dibromoanthrone/panlite L-1250 was sublimed as a carrier generating substance = 5
0/100 (weight ratio) was ground in a ball mill for 24 hours, 1,2-dichloroethane was added to make it 9vt%, and further dispersed in a ball mill for 24 hours.The carrier transport substance [structural formula (1)] was added to the liquid by panlite. 75vt% was added to L-1250. Monochlorobenzene was added to this dispersion and monochlorobenzene/1,2-dichloroethane-
A carrier generation layer with a thickness of 5 μm was formed by spray coating on the carrier transport layer, and the organic structural formula (1) of the present invention was prepared to have a volume ratio of 3/7 (volume ratio). 2,2'-methylenebis(6-t-butyl-4
-Methylphenol) to carrier transport material 1Q
0PC2 for comparison in the same manner except that vt% was further added.
I got it.

Examples and Comparative Examples In each of the Examples and Comparative Examples, the following image forming apparatus was used at a temperature of 20° C. and a relative humidity of 50% using a developer selected from the above-mentioned developers in the combinations listed in Table 2. Copied images were continuously formed 70,000 times under ambient conditions at room temperature, and each of the following items was evaluated.

The results of the evaluation are shown in Table 2.

(Image forming apparatus) Electrophotocopy machine rU-Bix 1550M RJ (
This is a modified machine manufactured by Konica Co., Ltd., and the main components are as follows.

(1) Photoreceptor As shown in Table 2, a photoreceptor selected from the organic photoreceptors described above was mounted.

(2) Developing device Equipped with a magnetic brush developer for two-component developers.

(3) A heat roller with a diameter of 30 nm whose surface layer of the fuser is made of Teflon (polytetrafluoroethylene manufactured by DuPont), and a back unroller whose surface layer is formed of silicone rubber rKE-1300RTVJ (manufactured by Shin-Etsu Chemical Co., Ltd.) Equipped with a heat roller fixing device.

(4) Cleaning device Equipped with a cleaning device equipped with a cleaning blade made of urethane rubber.

(Evaluation items) ■Using the fogging "Sakuraden 7tometer" (manufactured by Konica Corporation) -
The determination was made by measuring the relative density of the white background portion of the r, g document density of 0,0 with respect to the copied image. Note that the white background reflection density is 0.0.
And so. For evaluation, the case where the relative concentration is o, oi is not grooved is evaluated as “○”.
'', the case of 0.01 or more and less than 0.03 was marked as "Δ", and the case of 0.03 or more was marked as "x".

■Resolution Following JIS Z 4916, l+am as a blade
4.0, 5.0, 6.3, 8 equally spaced horizontal lines
．． Using a chart with 0 lines, the blades with discernible horizontal lines were displayed as resolution.

The sharpness of the 0-quality copied image was visually judged from the viewpoint of contrast. The evaluation was ``O'' if it was good, ``△'' if it was slightly bad but at a practical level, and ``x'' if it was bad and had a practical problem.

(2) Durability Considering the above three items and the clarity of the image, the overall durability was expressed in terms of the number of copies made.

As can be understood from the above results, according to the embodiments of the present invention, no fogging occurs even when copying is performed many times.
Clear images with excellent resolution and sharpness can be provided for a long period of time. Further, no offset phenomenon occurred, and no stains on the roller of the heat roller fixing device were observed.

On the other hand, according to Comparative Example (1), since neither the developer nor the photoreceptor contains an antioxidant, fogging occurs early, the resolution decreases, and the image becomes unclear with poor sharpness. It is recognized that the durability is inferior. It is also understood that in Comparative Example (2), the resolution is lower than the initial one, and if copies are repeated many times, fogging occurs, sharpness and resolution decrease, and durability deteriorates.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an image forming apparatus that can be suitably used to carry out the developing method using the developer according to the present invention. 50...Organic photoreceptor 51...Corona charger 52...Exposure optical system 53...Developer 54...Electrostatic transfer device 56...Blade type cleaning device 70...Heat roller fixing vessel

Claims (2)

[Claims] (1) An electrostatic image developing method comprising developing an electrostatic image formed on the surface of an organic photoreceptor with a developer containing toner particles and inorganic fine particles having an antioxidant fixed to the surface. (2) The average particle size of the inorganic fine particles is 0.01 to 2.0μ
The electrostatic image developing method according to claim 1, wherein m.