JPH08320588A - Image forming method - Google Patents

Abstract

PURPOSE: To obtain a photoreceptor which has high sensitivity, lessens the wear of an electrophotographic photoreceptor photosensitive layer and is lessened in degradation in image quality and deterioration in sensitivity by incorporating inorg. particulates into the extreme surface layer of the photoreceptor and an image forming method suitable therefor. CONSTITUTION: The photoreceptor has the photosensitive layer 6 of single layer constitution contg. both of a charge generating material(CGM) and a charge transfer material(CTM) via an intermediate layer 2 on a conductive base 1. The photoreceptor otherwise has the photosensitive layer 6 formed by laminating a charge transfer layer(CTL) 3 contg. the charge transfer material(CTM) as an essential component and a charge generating layer(CGL) 4 contg. the charge generating material(CGM) as an essential component via the intermediate layer 2 on the conductive base 1 in this order. The photoreceptor otherwise has the photosensitive layer 6 formed by laminating the charge generating layer(CGL) 4 and the charge transfer layer(CTL) 3 in this order via the intermediate layer 2 on the conductive base 1. The most preferable embodiment is obtd. by further laminating a protective layer 5 on the photosensitive layer 6 and incorporating the inorg. particles into this protective layer 5.

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 such as electrophotography, that is, an image forming method for visualizing an electrostatic image with a developer.

More specifically, a photoconductor such as an organic photoconductor is used in an electrophotographic process, and the photoconductor is arranged so as to come into contact with an image forming apparatus or a photoconductor which is charged by a charging member arranged so as to come into contact with the photoconductor. The present invention relates to an image forming method using a photosensitive body containing inorganic fine particles in the outermost surface layer in an image forming apparatus for transferring a toner image on the photosensitive body by the electrostatic transfer charging member.

[0003]

2. Description of the Related Art In an electrophotographic copying machine of the Carlson method, after uniformly charging the surface of a photoconductor, the charge is erased imagewise by exposure to form an electrostatic latent image. With toner, then transfer the toner to paper,
Fix it.

Hitherto, as a method of charging a photoreceptor, most of the time, a corona generated by applying a high voltage to a metal wire was used. However, in this method, when corona is generated, the surface of the photoconductor is deteriorated by discharge active species such as ozone and NO _x, and image blurring and deterioration are promoted, and wire stains affect image quality, resulting in white spots and black streaks. There was a problem that arises. In particular, organic photoconductors have a lower chemical stability than selenium photoconductors and amorphous silicon photoconductors, so they tend to deteriorate when exposed to discharge activated species, and repeated use causes image blurring and fog due to sensitivity deterioration. Tended to happen.

To solve such a problem, Japanese Patent Laid-Open No. 57-17
8267, JP 56-104351, JP 58-40566, and JP 58-13915.
As proposed in Japanese Patent Laid-Open No. 6-58, Japanese Patent Laid-Open No. 58-150975 and the like, methods of contact charging have been studied.

In the contact charging, a charging member such as a conductive elastic roller, a conductive elastic blade or a conductive brush is brought into contact with the surface of the photoconductor, and a DC voltage or a DC voltage superposed with an AC voltage is applied to the charging member. Then, the surface of the photoconductor is charged to a predetermined potential. In this case, since corona discharge is not used, almost no discharge active species are generated and chemical deterioration of the surface of the photoconductor can be prevented, while discharge dielectric breakdown easily occurs at a slight defective portion inside the photoconductor, resulting in white spots and the like. However, there is a defect that the image defect occurs. Further, it is known that this problem is particularly remarkable when the photosensitive layer is worn and the dielectric breakdown voltage is lowered.

Such a problem is caused by a conductive elastic roller, a conductive elastic blade, which are arranged so as to come into contact with the photosensitive member,
The same occurs when a DC voltage or a DC voltage obtained by superimposing an AC voltage is applied to an electrostatic transfer charging member such as a conductive brush to transfer a toner image on the photoconductor.

On the other hand, the photosensitive member has a function of removing adhered toner and removing charge.
The surface is cleaned and repeatedly used over a long period of time.
Therefore, as an electrophotographic photosensitive member, of course, electrophotographic characteristics such as good charging characteristics and sensitivity, and small dark decay,
In addition, physical properties such as printing durability, abrasion resistance, and moisture resistance after repeated use, and resistance to ultraviolet rays during exposure (environmental resistance)
It is also required to be good in.

As an electrophotographic photoreceptor, selenium, zinc oxide,
There is a trend to put into practical use organic photoconductors that can be selected from a wide range of substances exhibiting respective functions in view of desired characteristics in place of inorganic photoconductors such as cadmium sulfide, which are preferable in terms of pollution control.

Such an organic photoreceptor is conventionally mainly used for negative charging. As described in JP-A-60-247647, a thin charge generating layer is provided on a support, and a relatively thick charge is formed thereon. It is configured to have a transport layer. However, since the charge transport layer is composed of a polymer binder, a carrier transport material, etc., it is worn away by the developing sleeve, transfer paper, cleaning member, etc. during use, and gradually loses its initial charge characteristics and light attenuation characteristics. There was a problem that it would not be obtained. Further, when the contact charging method is adopted, there is a problem that the charging member is in contact with the photosensitive member, so that the photosensitive member is easily worn by the charging member and the above-mentioned image defect is easily generated.

As a binder resin for the outermost surface layer of the photoconductor, for example, a charge transport layer, a polycarbonate resin is preferably used from the viewpoint of electrophotographic characteristics, mechanical strength and the like.
The present situation is that sufficient performance has not yet been obtained in terms of scratch resistance and wear resistance. In addition, introduction of a substituent having a fluorine atom at a carbon between phenylene rings into a polycarbonate resin (JP-A-63-65444), substitution of an alkyl group or a halogen atom into a phenylene ring (JP-A-62-14).
8263), or phenyl groups on both phenylene rings,
Alternatively, copolymers of monomers substituted with a cyclohexyl group (JP-A-1-269942, 1-269943)
Etc. have been proposed. However, there are still problems such as insufficient surface strength, weakness against abrasion and scratches, deterioration of image quality during repeated use, and deterioration of sensitivity due to reduction of film thickness due to abrasion.

As a countermeasure against this, it has been proposed that the outermost surface layer contains organic fine particles or inorganic fine particles so that the surface has strength, but since fine particles having a large specific surface area are present on the surface, discharge activity of ozone or the like is caused. It was found that seeds are easily adsorbed and problems such as image blur occur. Therefore, when using the corona discharge method in which a large amount of discharge active species is generated, when a photoreceptor containing organic fine particles and inorganic fine particles in the outermost surface layer is used, image defects such as image blurring may occur especially due to the large surface adsorption area. It was easy to occur.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-sensitivity photoconductor with less wear of the photosensitive layer of the electrophotographic photoconductor, less deterioration of image quality and sensitivity deterioration, and an image using a charging method suitable for the photoconductor. An object is to provide an image forming method having excellent stability.

[0014]

The object of the present invention can be achieved by adopting any of the following constitutions.

(1) In an image forming method in which a charging member is placed in contact with a photosensitive layer of an electrophotographic photosensitive member and the photosensitive member is charged by applying a voltage, the outermost surface layer of the photosensitive member contains inorganic fine particles. An image forming method characterized by containing.

(2) An electrostatic transfer member is placed in contact with the photosensitive layer of the electrophotographic photosensitive member, and the electrostatic transfer member is passed between the photosensitive member and the electrostatic transfer member while the electrostatic transfer member is being passed. An image forming method for transferring a toner image on a photoconductor onto the transfer body by applying a voltage to a member, wherein the outermost surface layer of the photoconductor contains inorganic fine particles.

(3) The volume average particle diameter of the inorganic fine particles is 0.
The image forming method according to (1), which has a thickness of 05 to 2 μm.

(4) The image forming method as described in (1) or (2), wherein the inorganic fine particles are subjected to a hydrophobic treatment.

(5) The image forming method as described in (1), (2), (3) or (4), wherein the inorganic fine particles are silica.

In the present invention, the charging member or the transfer member is arranged so as to come into contact with the photosensitive layer of the photosensitive member, and the charging member and the like are installed so that the photosensitive layer can be contact-charged. The outermost surface layer of the photosensitive member It is usual that a part of the charging member or the transfer member, for example, the tip of a brush is pressed against the surface.

The inorganic particles contained in the outermost surface layer of the electrophotographic photosensitive member of the present invention are preferably hard particles having a Mohs hardness of 4 or more, and do not adversely affect the electrophotographic performance.

Examples of such inorganic particles include oxides such as cerium oxide, chromium oxide, aluminum oxide, magnesium oxide, silicon oxide, tin oxide, zirconium oxide, iron oxide and titanium oxide; calcium sulfate, barium sulfate and sulfuric acid. Sulfates such as aluminum; silicates such as calcium silicate and magnesium silicate; nitrides such as boron nitride and titanium nitride; silicon carbide, titanium carbide,
Carbides such as boron carbide, tungsten carbide, and zirconium carbide; borides such as zirconium boride and titanium boride, and the like can be used, and one of these can be used, or two or more can be used as necessary.

The inorganic particles have a volume average particle size of 0.05 to
2.0 μm, preferably a ratio of major axis / minor axis of 2.0
Less than substantially spherical particles.

The volume average particle diameter of the inorganic particles is 0.05 μ
If it is less than m, sufficient mechanical strength of the surface of the photoreceptor cannot be obtained, and the surface area of the particles becomes large. As a result, the amount of adsorbed water increases and the surface of the photoreceptor wears and is damaged during repeated image formation, resulting in electron Photo performance deteriorates. On the other hand, if it exceeds 2.0 μm, the surface roughness of the photoconductor becomes large, and the cleaning blade is worn or damaged to deteriorate the cleaning characteristics, resulting in poor cleaning and easy occurrence of image blur. When the inorganic particles are substantially spherical, the particles are not indefinite when enlarged to a size (diameter 1 to 10 mm) whose surface shape can be discriminated by an electron microscope, and the ratio of major axis / minor axis is less than 2.0. It is regarded as a sphere. In that case, the abrasion coefficient of the surface of the photoconductor can be reduced, and it is possible to prevent the reversal of the elastic cleaning blade, which has been a problem in the related art.

The volume average particle size of the inorganic particles is measured by a laser diffraction / scattering particle size distribution measuring device LA-700 (manufactured by Hikiba Seisakusho).

The inorganic particles are preferably hydrophobized with a hydrophobizing agent such as a titanium coupling agent, a silane coupling agent, a polymeric fatty acid or a metal salt thereof.

Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate and the like. Further, as the silane coupling agent, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltri Methoxysilane,
Examples thereof include dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane and the like.

The fatty acids and metal salts thereof include undecyl acid, lauric acid, tridecanoic acid, myristic acid,
Palmitic acid, pentadecanoic acid, stearic acid, heptadecanoic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, long chain fatty acids such as arachidonic acid, and the like, as its metal salt, zinc, iron, magnesium, aluminum, calcium, Examples thereof include salts with metals such as sodium and lithium.

These compounds are preferably added in an amount of 1 to 10% by weight with respect to the above-mentioned inorganic particles for coating, preferably 3 to 7% by weight. Further, these materials can be used in combination, and the surface of the inorganic particles is usually covered with a monomolecular layer or a layer close thereto.

In the present invention, silica particles are particularly preferably used as the inorganic particles contained in the outermost surface layer of the photoreceptor, and further, silica particles having low hygroscopicity and few active hydroxyl groups on the surface are preferably used. To be

Such silica particles have an endothermic peak in the range of 40 to 200 ° C. by a differential scanning calorimetry method, and in an environment of 80% RH, the energy change amount ΔH of the endothermic peak is 20 J /. g or less. More preferably, the silica particles are treated with a hydrophobizing agent such as the silane coupling agent so that the energy change amount ΔH is 10 J / g or less.

The hydrophobic treatment of the silica particles is achieved by reacting the silanol groups on the silica surface with the above-mentioned hydrophobic treatment agent by a chemical reaction.

As a method for hydrophobizing the silica particles, for example, a method of reacting silanol groups with trimethylchlorosilane under high pressure (Kolloid-Z, 149,
39 (1956)), esterification with alcohol (DB
P 1074559) esterification in an autoclave, (Bull. Chem. Soc. Jpn. 49 (1
2), 3389 (1976)) and the like,
In particular, a treatment method using a silane coupling agent is common. The treatment method with a silane coupling agent can be performed by, for example, the method described in “Silane coupling agent” (Shin-Etsu Chemical Co., Ltd.), “Technical data No. Z003” (Toshiba Silicone), or the like.

The silica particles having a low hygroscopicity and a small amount of active species on the surface as described above are formed by chemical flame CVD (CV).
D: Chemical Vapor Deposition
On) method, among them, it is preferable to introduce the metallic silicon powder into a mixed gas for combustion, and explosively combust and react with it.

The details of this manufacturing method are described in, for example, JP-A-60-2.
55602, JP-A-5-193908 and 5-19.
No. 3909, No. 5-193910, No. 5-19392
No. 8, No. 5-196614, and No. 6-107406.

In the manufacturing method described in each of the above publications, the raw material silicon metal material is washed with high-purity water a plurality of times in advance to remove dissolved components, and at the same time, heat treatment is performed to remove gas phase components and increase the temperature. A fine silicon powder is obtained. Next, a combustible gas such as LPG and a supporting gas such as oxygen gas are introduced into a burner at the head of the manufacturing apparatus to form a flame for ignition, and the high-purity silicon powder is added to the flame for ignition. A carrier gas such as air dispersedly contained is introduced to start ignition and combustion. After that, the combustion-supporting gas is supplied in multiple stages to explosively oxidize and burn the silicon powder to obtain high-purity silica particles.

According to the above production method, high-purity silica particles having an endothermic peak energy change amount ΔH in the differential scanning calorimetry of usually 10 J / g or less and having a sharp particle size distribution can be obtained. In addition, the particle size distribution can be varied over a wide range according to the purpose.

The silica particles produced as described above contain very few impurities and contain 1 aluminum component.
000 ppm or less, preferably 200 to 1 ppm, calcium component is 300 ppm or less, preferably 50 to 1 p
pm, iron component is 1000 ppm or less, preferably 200
It is set to a range of 1 ppm. A in the silica particles
l and Fe are measured by ICP emission spectrometry, and Ca is measured by flameless atomic absorption spectrometry.

In the present invention, these inorganic particles are contained at least in the outermost surface layer of the electrophotographic photosensitive member together with the binder. The proportion of the inorganic particles in the outermost surface layer is usually 1% by weight or more and 200% by weight or less with respect to the binder. Desirably 5% by weight
Used above 100% by weight.

The outermost surface layer of the present invention may be a photosensitive layer located on the outermost surface of the electrophotographic photosensitive member, or may be a protective layer laminated thereon.

The photosensitive layer of the electrophotographic photosensitive member of the present invention in which the above-mentioned inorganic particles are contained in the outermost surface layer may be an inorganic photosensitive member using selenium, amorphous silicon, cadmium sulfide, etc., but is preferably. Organic charge generation material (CG
M) and a charge transport material (CTM). The layer structure of the organic photoreceptor is shown in FIG.

FIG. 1A shows an intermediate layer 2 on a conductive support 1.
1 is a photoreceptor having a single-layer photosensitive layer 6 containing both a charge-generating substance (CGM) and a charge-transporting substance (CTM) via an intermediate layer 2 on a conductive support 1. Charge transport layer (CTL) containing a charge transport material (CTM) as a main component via
And a charge generation layer (CGL) 4 containing a charge generation material (CGM) as a main component, and a photosensitive layer 6 formed in this order. FIG. And a photoconductive layer 6 formed by laminating a charge generation layer (CGL) 4 and a charge transport layer (CTL) 3 in this order via an intermediate layer.

Further, FIGS. 1D, 1E, and 1H show the protective layer 5 on the photosensitive layer of FIGS. 1A, 1B, and 1C, respectively.
The structure which laminated | stacked is shown. Above (a), (b), (c),
Each of (d), (e) and (f) shows a typical constitution of the organic photoconductor, and the present invention is not limited to these layer constitutions. For example, the intermediate layer 2 shown in these figures may be omitted if not necessary.

Among the above-mentioned layer constitutions, the most preferable embodiment of the present invention is that a protective layer 5 is further laminated on the photosensitive layer as shown in (d), (e) and (f), and In which the inorganic particles of the present invention are contained.

The protective layer, when provided, is composed of at least a resin and the inorganic particles of the present invention, but it is more preferable to include a charge transporting substance (CTM) in the protective layer. Inclusion of a charge transport material (CTM) in these protective layers can prevent an increase in residual potential and a decrease in sensitivity due to repeated use of the electrophotographic photosensitive member.

Examples of the charge generating substance (CGM) contained in the photosensitive layer 6 of each of the photoreceptors shown in FIGS. 1 (a) to 1 (f) are, for example, phthalocyanine pigments, polycyclic quinone pigments, azo pigments, perylene pigments and indigo pigments. Pigments, quinacridone pigments, azurenium pigments, squarylium dyes, cyanine dyes, pyrylium dyes, thiopyrylium dyes, xanthene dyes, triphenylmethane dyes, styryl dyes, and the like, and these charge generating substances (CGM) alone or in a suitable binder. Layer formation is performed together with the resin.

The charge transport material (C
(TM), for example, oxazole derivative, oxadiazole derivative, thiazole derivative, thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazoline derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, benzidine compound, pyrazoline derivative, stilbene derivative Compounds, amine derivatives, oxazolone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinazoline derivatives,
Examples include benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc.These charge transport materials (CTM) are usually formed with a binder to form a layer. Is done.

Of these, particularly preferred charge transport materials (C
Examples of TM) include compounds represented by the following general formula.

[0049]

Embedded image

(In the formula, Ar ₁ , Ar ₂ and Ar ₄ each represent a substituted or unsubstituted aromatic hydrocarbon group or a heterocyclic group, and Ar ₃ represents a substituted or unsubstituted divalent aromatic hydrocarbon group. Group or heterocyclic group, R ₂ represents a hydrogen atom or a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group, n is 1 or 2. Ar ₄ and R ₂ are bonded to each other to form a ring. It may be formed.)

[0051]

Embedded image

(In the formula, R ₃ and R ₄ each represent a substituted or unsubstituted aromatic hydrocarbon group, heterocyclic group or alkyl group, which may be linked to each other to form a ring. R ₅ is hydrogen. An atom or a substituted or unsubstituted aromatic hydrocarbon group, a heterocyclic group or an alkyl group is represented, Ar ₅ is a substituted or unsubstituted aromatic hydrocarbon group or a heterocyclic group, and m is 0 or 1.
Is. )

[0053]

Embedded image

(In the formula, Y is a monovalent substituted or unsubstituted phenyl group, naphthyl group, pyrinyl group, fluorenyl group,
It represents a carbazolyl group, a diphenyl group and a 4,4'-alkylidene diphenyl group, and Ar ₆ and Ar ₇ each represent a substituted or unsubstituted aromatic hydrocarbon group or a heterocyclic group. l represents an integer of 1 to 3. )

[0055]

[Chemical 4]

(In the formula, Ar ₈ , Ar ₉ , Ar ₁₀ and Ar ₁₁ each represent a substituted or unsubstituted aromatic hydrocarbon group or a heterocyclic group,
Ar ₁ , Ar ₂ and Ar ₃ are as described above. Among these, specific compound examples preferably used in the photoconductor of the present invention are illustrated below.

[0057]

Embedded image

[0058]

[Chemical 6]

[0059]

[Chemical 7]

[0060]

Embedded image

[0061]

[Chemical 9]

[0062]

[Chemical 10]

As the binder resin contained in the photosensitive layer 6 having the single-layer structure and the charge-generating layer (CGL) and the charge-transporting layer (CTL) in the case of the laminated structure, polyester resin, polystyrene resin, methacrylic resin, acrylic resin are used. , Polyvinyl chloride resin, polyvinylidene chloride resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl acetate resin, styrene-butadiene resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-maleic anhydride copolymer resin, urethane resin, Silicon resin Epoxy resin, silicon-alkyd resin, phenol resin, polysilane resin, polyvinyl carbazole and the like can be mentioned.

The binder resin contained in the uppermost layer of each of the photoconductors shown in FIGS. 1 (a) to 1 (f) is preferably resistant to mechanical shock and has high abrasion resistance, and has excellent electrophotographic performance. Those that do not interfere are better. Preferred binder resins include polycarbonate resins having a structural unit represented by the following general formula (I), (II), (III) or (IV).

[0065]

[Chemical 11]

(In the formula, R _{1 to} R ₈ are hydrogen atoms, halogen atoms, substituted or unsubstituted C 1-10 alkyl groups, cycloalkyl groups or aryl groups, and Z is 4-11 carbon atoms. A saturated or unsaturated carbocycle-forming residue having R, R
₉ is an alkyl group or an aryl group having 1 to 9 carbon atoms. )

[0067]

[Chemical 12]

(In the formula, R ₁₁ to R ₁₈ each independently represent a hydrogen atom, a halogen atom, an alkyl group or an aryl group.)

[0069]

[Chemical 13]

(In the formula, R _{21 to} R ₂₈ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted C 1-10 alkyl group, a cycloalkyl group, or an aryl group.)

[0071]

Embedded image

(In the formula, R _{31 to} R ₄₆ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or an aryl group, and k and m are positive integers, and k / m Is selected to be 1 to 10.) The polycarbonate resin having the structural unit represented by the general formula is preferably one having a weight average molecular weight of 30,000 or more.

Next, as the solvent or dispersion medium used in forming each of the layers, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylketone , Methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,
Examples thereof include 2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropinal, ethyl acetate, butyl acetate, dimethyl sulfoxide, and methyl cellosolve. The present invention is not limited to these, but when a ketone solvent is used, the sensitivity and potential change during repeated use are further improved. Further, these solvents may be used alone or as a mixed solvent of two or more kinds.

In the present invention, the weight ratio of the charge generating substance to the binder resin in the charge generating layer is preferably 1: 5 to 5: 1. The thickness of the charge generation layer is preferably 5 μm or less,
It is particularly preferably 0.05 to 2 μm.

Further, the charge-transporting material of the charge-transporting layer and the binder resin are dissolved in a suitable solvent, and the solution is applied and dried. The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1:00 by weight.

The thickness of the charge transport layer is preferably 5 to 50 μm, more preferably 10 to 40 μm.

When the photoreceptor is a single layer type, it can be obtained by coating and drying a solution in which the above-mentioned charge generating substance and charge transporting substance are dispersed and dissolved in a binder resin.

When the outermost surface of the present invention is formed of a protective layer,
The protective layer dissolves the resin and the inorganic particles of the present invention together with a solvent,
It is formed by dispersing and coating on the above-mentioned photosensitive layer. In this case, it is preferable to add a charge transport material (CTM) to the protective layer. The ratio of resin to CTM in the protective layer is 10:
1 to 1:10 is preferable. The thickness of the protective layer is preferably 0.2 to 10 μm. If it is less than 0.2 μm, the effect of the present invention is difficult to obtain. If it exceeds 10 μm, the resolution of the image is deteriorated due to light scattering by the inorganic particles in the protective layer. Further, the sensitivity may decrease and the residual potential may increase. Particularly preferred range is 0.4
~ 5 μm.

Next, as a conductive support for the electrophotographic photosensitive member of the present invention, 1) a metal plate such as an aluminum plate or a stainless plate, 2) aluminum, palladium or gold on a support such as paper or a plastic film. 3) A thin metal layer such as is provided by lamination or vapor deposition, 3) A layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is provided by coating or vapor deposition on a support such as paper or plastic film The thing etc. are mentioned.

Next, as a coating method for manufacturing the electrophotographic photosensitive member of the present invention, dip coating, spray coating,
Although coating processing methods such as circular amount control type coating are used, the coating process on the surface layer side of the photosensitive layer does not dissolve the lower layer film as much as possible, and spray coating or circular amount control type coating to achieve uniform coating process. It is preferable to use a coating processing method such as. The spray coating is described in, for example, JP-A-3-90.
No. 250 and JP-A-3-269238, the details of the circular amount control type coating are described in, for example, JP-A-58-189061.

According to the spray coating and the circular amount regulation coating, as compared with the dip coating, the coating liquid is not wasted, the lower layer is not dissolved or damaged, and uniform coating is achieved. And so on.

In the present invention, an undercoat layer having both a barrier function and an adhesive resin may be provided between the photosensitive layers of the conductive support.

Materials for the undercoat layer include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin polyamides (nylon 6, nylon 66, nylon 61).
0, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide and the like. The thickness of the undercoat layer is preferably 0.1 to 10 μm, particularly preferably 0.1 to 5 μm.

In the present invention, a coating for compensating for surface defects of the support is provided between the support and the undercoat layer, and interference fringes which become a problem particularly when the image input is laser light. It is possible to provide a conductive layer for the purpose of preventing the occurrence of This conductive layer is carbon black,
It can be formed by coating and drying a solution in which a conductive powder such as metal particles or metal oxide particles is dispersed in a suitable binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm.

The shape of the support may be drum-shaped, sheet-shaped, or belt-shaped, and is preferably a shape most suitable for the electrophotographic apparatus to which it is applied.

The image holding member of the present invention can be applied to general electrophotographic apparatuses such as copying machines, laser printers, LED printers and liquid crystal shutter printers.
Further, it can be widely applied to devices such as displays, recording, light printing, plate making, and facsimiles to which electrophotographic technology is applied.

FIG. 2 shows a schematic structural example of an image forming apparatus having the electrophotographic photosensitive member of the present invention.

In FIG. 2, reference numeral 10 is a photosensitive drum which is an image bearing member, and an organic photosensitive layer is coated on the drum and is grounded and driven and rotated clockwise. Reference numeral 12 denotes a scorotron charger, which applies uniform charging to the peripheral surface of the photosensitive drum 10 by corona discharge. Prior to the charging by the charging device 12, the peripheral surface of the photoconductor may be erased by performing exposure by 11 using a light emitting diode or the like in order to eliminate the history of the photoconductor in the previous image formation.

After uniformly charging the photosensitive member, the image exposing means 13 performs image exposure based on the image signal. The image exposure means 13 in this figure bends the optical path by a reflection mirror 132 via a polygon mirror 131, an f.theta. Lens, etc., which rotate using a laser diode (not shown) as a light source, and scans the photosensitive drum to form an electrostatic latent image. To be done.

The electrostatic latent image is then developed by the developing device 14. At the periphery of the photosensitive drum 10, there are provided developing devices 14 each containing a developer composed of toner such as yellow (Y), magenta (M), cyan (C), and black (K), and a carrier. The development of the first color is carried out by the developing sleeve 141 which contains a magnet and holds the developer and rotates. The developer is a carrier in which ferrite is used as a core and an insulating resin is coated around the core, a polyester is used as a main material, a pigment corresponding to a color, a charge control agent, silica,
It is composed of toner added with titanium oxide, etc., and the developer is 100-600 μm on the developing sleeve 141 by the layer forming means.
The layer thickness is regulated by the layer thickness and the sheet is conveyed to the developing area and development is performed. At this time, normally, a DC or AC bias potential is applied between the photosensitive drum 10 and the developing sleeve 141 to perform development.

In the color image formation, after the visualization of the first color is completed, the process for forming the second color image is started, and the scorotron charger 12 performs uniform charging again to form the latent image of the second color image. It is formed by the exposure means 13. An image forming process similar to that for the second color is performed for the third and fourth colors, and a visible image of four colors is formed on the peripheral surface of the photosensitive drum 10.

On the other hand, in the monochrome electrophotographic apparatus, the developing device 14
Is composed of one kind of black toner, and an image can be formed by one development.

After the image formation, the recording paper P is fed to the transfer area by the rotation operation of the paper feed roller 17 when the transfer timing is adjusted.

In the transfer area, the transfer roller 18 is pressed against the peripheral surface of the photosensitive drum 10 in synchronization with the transfer timing.
The supplied recording paper P is sandwiched and the multicolor image is transferred at once.

Then, the recording paper P is discharged at almost the same time by the separating brush 19 which is brought into a pressure contact state, separated by the peripheral surface of the photosensitive drum 10 and conveyed to the fixing device 20, where the heat roller 201
The toner is fused by heating and pressurizing the pressure roller 202, and then the toner is ejected to the outside of the apparatus through the paper ejection roller 21. The transfer roller 18 and the separation brush 19 are withdrawn from the peripheral surface of the photosensitive drum 10 after the recording paper P has passed and are ready for the next toner image formation.

On the other hand, the photosensitive drum after the recording paper P is separated
Reference numeral 10 denotes a cleaning device 22 in which a blade 221 is pressed to remove and clean residual toner.
After receiving the electric charge from 12, the next image forming process starts. When superimposing a color image on the photoconductor, the blade 221 moves immediately after cleaning the photoconductor surface and retracts from the peripheral surface of the photoconductor drum 10.

Reference numeral 30 is a removable cartridge in which the image holding member, the charging means, the developing means and the cleaning means are integrated.

An electrophotographic apparatus is constructed by integrally combining a plurality of components such as the above-mentioned photosensitive member, developing means, cleaning means and the like as an apparatus unit, and this unit can be detachably attached to the apparatus main body. It may be configured to.
For example, a unit is formed by integrally supporting at least one of a charging unit, a developing unit, and a cleaning unit together with a photoconductor to form a unit, which is detachably attached to the apparatus body, and is attached and detached by using a guide unit such as a rail of the apparatus body. It may be configured freely. At this time, the above device unit may be provided with a charging unit and / or a developing unit.

When the electrophotographic apparatus is used as a copying machine or a printer, the image exposure means irradiates the photoconductor with reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal. According to the method, the laser beam is scanned, the LED array is driven, or the liquid crystal shutter array is driven to irradiate the photoconductor with light.

When used as a facsimile printer, the image exposure means 13 is used for printing the received data.

[0101]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

(1) Preparation of Photoreceptor Photoreceptor 1-1 Polyamide resin CM-8000 (Toray Industries, Inc.) (30 g) was placed in a mixed solvent of methanol (900 ml) and 1-butanol (100 ml), and heated and dissolved at 50 ° C. After cooling to room temperature, using this liquid, the outer diameter was 80 mm and the length was 355.5.
An intermediate layer having a thickness of 0.5 μm was formed by dip coating on a mm aluminum drum.

Next, 5 g of polyvinyl butyral resin S-REC BX-1 (Sekisui Chemical Co., Ltd.) was dissolved in 1000 ml of methyl ethyl ketone (MEK), and 10 g of the following "Chemical 15" compound CGM-1 was mixed, followed by using a sand mill. For 20 hours. Using this solution, a charge generation layer having a thickness of 0.5 μm was formed by dip coating on the intermediate layer.

Thereafter, 100 g of Exemplified Compound T-31
And BPZ type polycarbonate resin Panlite TS-20
50 (Teijin Kasei) 150 g dichloromethane 10
Dissolved in 00 ml. Using this solution, a charge transport layer having a thickness of 20 μm was formed on the charge generation layer by dip coating.

Then, 20 g of Exemplified Compound T-31 and BPZ type polycarbonate resin Panlite TS-205 were used.
0 (Teijin Kasei) 30 g dichloromethane 1000
10 g of 0.2 μm silica fine particles (Mohs hardness 7.0 spherical) treated with a silane coupling agent were added to the liquid dissolved in ml, and dispersed in an ultrasonic bath for 20 minutes. Using this solution, a thickness of 3 is obtained by ring coating on the charge transport layer.
A μm surface protective layer was formed.

Finally, it was heated and dried at 100 ° C. for 1 hour to prepare a photoreceptor in which an intermediate layer, a charge generation layer, a charge transport layer and a surface protective layer were sequentially laminated.

[0107]

[Chemical 15]

Photoreceptor 1-2 Receptor 1 except that 0.2 μm silica fine particles were changed to 0.05 μm silica fine particles (Mohs hardness 7.0 spherical)
A photoconductor was prepared in the same manner as in 1.

Photosensitive member 1-3 Photosensitive member 1-1 except that 0.2 μm silica fine particles were changed to 2.0 μm silica fine particles (Mohs hardness 7.0 spherical).
A photoconductor was prepared in the same manner as in.

Photosensitive member 1-4 Photosensitive member 1-1 except that the silica fine particles of 0.2 μm were changed to the silica fine particles of 2.5 μm (Mohs hardness 7.0 spherical).
A photoconductor was prepared in the same manner as in.

Photosensitive member 1-5 Photosensitive member 1-5 except that 0.2 μm silica fine particles were changed to 0.2 μm zirconia (Mohs hardness 7.5) fine particles.
A photoconductor was prepared in the same manner as in 1.

Photoreceptor 1-6 Photoreceptor 1-1 except that 0.2 μm silica fine particles were changed to 0.1 μm silica fine particles (Mohs hardness 7.0 spherical).
A photoconductor was prepared in the same manner as in.

Photosensitive member 1-7 Photosensitive member 1-1 except that 0.2 μm silica fine particles were changed to 0.5 μm titanium oxide fine particles (Mohs hardness 6.0).
A photoconductor was prepared in the same manner as in.

Photoreceptor 1-8 A photoreceptor was prepared in the same manner as the photoreceptor 1-1, except that 0.2 μm silica fine particles were changed to 0.5 μm alumina fine particles (Mohs hardness 9.0).

Photoconductor 1-9 A photoconductor was prepared in the same manner as photoconductor 1-1 except that fine particles were not added.

(2) Evaluation U-BIX41 manufactured by Konica Corporation was used as the photoconductors 1-1 to 1-9.
It was mounted on a 55 modified machine, and 100,000 copies of live-action tests were conducted under different conditions as shown in the table below. The evaluation was performed based on the presence / absence of an image defect during actual shooting, the amount of change in surface potential before and after actual shooting, and the amount of film thickness loss.

<Electrostatic Characteristic Test> Using a modified machine in which the developing device of the copying machine is removed and a surface electrometer is provided at that position, a black paper potential (Vb), a white paper potential (Vw) and a residual potential (V) are used.
r) was measured and the results are shown in Table 1.

The black paper potential is the surface potential of the photoconductor when image exposure is performed using a black paper document having a reflection density of 1.3, and the white paper potential is image exposure using a white paper document having a reflection density of 0.0. It is the surface potential of the photoconductor when it is carried out. The residual potential is the potential before recharging after removing the charge after cleaning.

<Evaluation of image> The above 9 kinds of photoconductors were sequentially mounted on the copying machine, and 100,00 was used for the original having halftone.
Images were printed 0 times. During this period, the presence or absence of background fog due to poor cleaning and the presence or absence of image scratches due to blade cleaning reversal were evaluated.

<Amount of Depletion of Film Thickness> The uniform film thickness portion of the photoconductor is randomly measured at 10 places, and the average value is taken as the film thickness of the photoconductor. Film thickness meter EDDY 560C (HELMUT FISCHER GMBHT CO
(Manufactured by Mfg. Co., Ltd.) was used to measure the film thickness after the first time and after 100,000 copies, and the difference was defined as the amount of film thickness loss.

[0121]

[Table 1]

As shown in the table above, in the image forming method of the present invention,
It can be seen that even when repeatedly used, the film thickness of the photoconductor is less likely to be worn, and a stable image can be obtained without causing cleaning failure.

Example 2 (1) Preparation of Photoreceptor Photoreceptor 2-1 30 g of polyamide resin CM-8000 (Toray Industries, Inc.) was put into a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol, and heated and dissolved at 50 ° C. did. After cooling to room temperature, using this liquid, the outer diameter was 80 mm and the length was 355.5.
An intermediate layer having a thickness of 0.5 μm was formed by dip coating on a mm aluminum drum.

Next, 5 g of polyvinyl butyral resin S-REC BX-1 (Sekisui Chemical Co., Ltd.) was added to MEK1000.
Dissolved in ml, and further exemplified compound CGM-2 10 g
After mixing, the mixture was dispersed for 20 hours using a sand mill. Using this solution, a charge generation layer having a thickness of 0.5 μm was formed by dip coating on the intermediate layer.

Then, 100 g of the exemplified compound T-31
And BPZ type polycarbonate resin Panlite TS-20
50 (Teijin Kasei) 150 g dichloromethane 10
Dissolved in 00 ml. Using this solution, a charge transport layer having a thickness of 20 μm was formed on the charge generation layer by dip coating.

Thereafter, 20 g of Exemplified Compound T-31 and BPZ type polycarbonate resin Panlite TS-205 were used.
0 (Teijin Kasei) 30 g dichloromethane 1000
10 g of 0.2 μm silica fine particles (Mohs hardness 7.0 spherical) treated with a silane coupling agent were added to the liquid dissolved in ml, and dispersed in an ultrasonic bath for 20 minutes. Using this solution, a thickness of 3 is obtained by ring coating on the charge transport layer.
A μm surface protective layer was formed.

Finally, it was heated and dried at 100 ° C. for 1 hour to prepare a photoreceptor in which an intermediate layer, a charge generation layer, a charge transport layer and a surface protective layer were sequentially laminated.

[0128]

Embedded image

Photoconductor 2-2 A photoconductor was prepared in the same manner as the photoconductor 1 except that the silica fine particles of 0.2 μm were replaced with the silica fine particles of 0.05 μm (Mohs hardness 7.0 spherical).

Photoreceptor 2-3 A photoreceptor was prepared in the same manner as the photoreceptor 1 except that the 0.2 μm silica fine particles were changed to 2.0 μm silica fine particles (Mohs hardness 7.0 spherical).

Photoreceptor 2-4 A photoreceptor was prepared in the same manner as the photoreceptor 1, except that the 0.2 μm silica fine particles were changed to the 2.5 μm silica fine particles (Mohs hardness 7.0 spherical).

Photoconductor 2-5 A photoconductor was prepared in the same manner as photoconductor 1 except that 0.2 μm silica fine particles were changed to 0.2 μm zirconia (Mohs hardness 7.5) fine particles.

Photoreceptor 2-6 A photoreceptor was prepared in the same manner as the photoreceptor 1 except that the 0.2 μm silica fine particles were changed to the 0.1 μm silica fine particles (Mohs hardness 7.0 spherical).

Photoreceptor 2-7 A photoreceptor was prepared in the same manner as the photoreceptor 1 except that the 0.2 μm silica fine particles were changed to 0.5 μm titanium oxide fine particles (Mohs hardness 6.0).

Photoreceptor 2-8 A photoreceptor was prepared in the same manner as the photoreceptor 1, except that 0.2 μm silica fine particles were changed to 0.5 μm alumina fine particles (Mohs hardness 9.0).

Photoreceptor 2-9 A photoreceptor was prepared in the same manner as photoreceptor 1 except that fine particles were not added.

(2) Evaluation U-BIX41 manufactured by Konica Corp. was used as the photoconductors 2-1 to 2-9.
It was mounted on a 55 modified machine, and 100,000 copies of live-action tests were conducted under different conditions as shown in the table below. The evaluation was performed based on the presence / absence of an image defect during actual shooting, the amount of change in surface potential before and after actual shooting, and the amount of film thickness loss.

[0138]

[Table 2]

As shown in the table above, in the image forming method of the present invention,
It can be seen that even when repeatedly used, the film thickness of the photoconductor is less likely to be worn, and a stable image can be obtained without causing cleaning failure.

[0140]

INDUSTRIAL APPLICABILITY According to the present invention, a photoreceptor having high sensitivity, less wear of the photosensitive layer of the electrophotographic photoreceptor, less deterioration of image quality and less sensitivity deterioration, and image stability using a charging method or a transfer method suitable for the same are provided. An excellent image forming method can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a layer structure of a photoreceptor according to the present invention.

FIG. 2 is a sectional view of an image forming apparatus according to the present invention.

[Explanation of symbols]

 1 Conductive Support 2 Intermediate Layer 3 Charge Transport Layer (CTL) 4 Charge Generation Layer (CGL) 5 Protective Layer 6 Photosensitive Layer

Claims (5)

[Claims] 1. An image forming method in which a charging member is placed in contact with a photosensitive layer of an electrophotographic photosensitive member and the photosensitive member is charged by applying a voltage, and the outermost surface layer of the photosensitive member contains inorganic fine particles. An image forming method characterized by: 2. An electrostatic transfer member is arranged so as to be in contact with a photosensitive layer of an electrophotographic photosensitive member, and the electrostatic transfer member is passed between the photosensitive member and the electrostatic transfer member at the same time. An image forming method for transferring a toner image on a photoconductor onto the transfer body by applying a voltage to the photoconductor, wherein the outermost surface layer of the photoconductor contains inorganic fine particles. 3. The volume average particle diameter of the inorganic fine particles is 0.05 to.
The image forming method according to claim 1, having a thickness of 2 μm. 4. The image forming method according to claim 1, wherein the inorganic fine particles are hydrophobized. 5. The image forming method according to claim 1, 2, 3 or 4, wherein the inorganic fine particles are silica.