JPH096100A - Image forming method and device - Google Patents

Abstract

PURPOSE: To provide an image forming method and a device therefor where deterioration caused by the wear and damage of a photoreceptor and ozone is eliminated even if image-forming is repeatedly performed and high image quality is stably obtained over a long period. CONSTITUTION: As for the image forming method by which the images of many pages are formed by repeating a process where the photoreceptor 10 is electrified, and a toner image is transferred on a transfer body after development with toner after the exposure of the image and the photoreceptor 10 after transferring is cleaned; the uppermost layer of the photoreceptor 10 incorporates inorganic particles whose Mohs hardness is >=5, and the film strength of the uppermost layer is as the depth of the damage of 0.1-1.0μm at the time of exerting the vertical load of 200g using a diamond needle whose top end radius is 0.3mm, and it is a discharging type electrifier having an aperture part where air flows in the shielding member 114 of the electrifier 111 electrifying the photoreceptor 10, and the air at the inside of an image forming equipment is exhaused at the quantity of 0.1m<3> /min by an exhausting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming method and an image forming apparatus used for color or monochrome copying machines, printers, facsimiles and the like.

[0002]

2. Description of the Related Art In the electrophotographic image forming method of the Carlson method, after uniformly charging the surface of a photoreceptor, the charge is erased imagewise by exposure to form an electrostatic latent image. After developing the image with toner, the toner image is transferred to paper or the like and then fixed.

On the other hand, the photoreceptor is cleaned and discharged to remove the toner remaining on the surface, and is repeatedly used for a long period of time. Therefore, as an electrophotographic photoreceptor,
In addition to the electrophotographic characteristics such as good charging characteristics and good sensitivity and small dark decay, in addition to physical characteristics such as printing durability, abrasion resistance, moisture resistance after repeated use, and ultraviolet rays during exposure, etc. Good resistance (environmental resistance) is also required.

Recently, selenium, zinc oxide, cadmium sulfide, and other inorganic photoconductors are preferred as electrophotographic photoconductors in view of pollution control, and substances exhibiting various functions in accordance with desired characteristics are selected from a wide range. There is a trend to put the organic photoconductor into practical use.

Conventionally, such an organic photoreceptor is 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 layer is formed thereon. A structure in which a charge transport layer is provided is adopted. 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.

As a countermeasure against this, it has been proposed that the outermost surface layer (uppermost layer) contains colloidal silica or organic fine particles so that the surface has strength. However, it has been found that since particles having a large specific surface area are present on the outermost surface, discharge active species such as ozone are likely to be adsorbed, which causes a problem such as image blur. This tendency is particularly strong when the corona discharge method, which generates a large amount of discharge active species, is used.

[0007]

The present inventors have previously found that this problem can be considerably solved by incorporating inorganic particles having a relatively large particle size in the uppermost layer of the photoreceptor.

However, by containing particles in the uppermost layer of the photoconductor, the photoconductor surface becomes a rough surface with many irregularities, and since the surface area is large, it becomes more susceptible to the action of active gas such as ozone.

Conventionally, the fatigue-deteriorated layer on the surface of the photosensitive member has been refined by including an abrasive such as silica or cerium oxide in a developer. However, there is a problem that the surface of the photoconductor having the inorganic particles contained in the uppermost layer as described above becomes hard and the projections and depressions are severe, which makes it difficult to perform fining.

On the other hand, as a countermeasure against ozone deterioration of the photoconductor, investigations have been made from the aspect of the apparatus. For example, JP-A-62-9
No. 2971 discloses a method in which an exhaust fan is attached to an image forming apparatus to forcibly discharge air containing ozone in a charger. Further, JP-A-58-190967
JP-A-64-57277 and the like disclose related technologies, but the relationship between these and the structure of the photoconductor is not clear and is not a sufficient solution.

The object of the present invention is to prevent the photoreceptor from being worn, damaged, and deteriorated by ozone even if images are repeatedly formed.
An object of the present invention is to provide an image forming method and an image forming apparatus that can stably obtain high image quality over a long period of time.

[0012]

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

[1] An image in which a large number of images are formed by repeating the steps of charging a photoreceptor, developing an image-exposed toner with a toner, transferring a toner image onto a transfer body, and cleaning the photoreceptor after transfer. In the forming method, the uppermost layer (outermost surface layer) of the photoreceptor contains inorganic particles having a Mohs hardness of 5 or more,
In addition, the uppermost layer has a film strength of 0.1 to 1.0 μm when a vertical load of 200 g is applied using a diamond needle having a tip radius of 0.3 mm, and a charger for charging the photoreceptor. Is a discharge type charger having an opening through which an air flow flows, and the air in the image forming apparatus is exhausted by an exhaust means at an amount of 0.1 m ³ / min or more. Image forming method.

[2] The photoconductor has a structure in which a plurality of layers containing a charge transporting material are laminated on a charge generating layer, and the uppermost layer is a layer containing a charge transporting material [ 1] The image forming method described above.

[3] The image forming method as described in [1] or [2], wherein the inorganic particles contained in the outermost surface layer of the photoreceptor have a volume average particle diameter of 0.05 to 2 μm.

[4] An image forming apparatus for forming a large number of images having a photoconductor, a photoconductor charging unit, an image exposing unit, a toner developing unit, a unit for transferring a toner image onto a transfer body, and a photoconductor cleaning unit. The depth of scratches when a vertical load of 200 g is applied by using a diamond stylus containing inorganic particles having a Mohs hardness of 5 or more in the uppermost layer of the photoconductor and the film strength of the uppermost layer is 0.3 mm in tip radius. Is 0.1
1.0 μm, the photoconductor charging means is a discharge type charger having a shield member having an opening through which air flows, and the airflow passes from the photoconductor side through the inside of the charger to the shield member of the charger. An image forming apparatus, characterized in that it is configured to flow out from an opening.

As described above, an object of the present invention is to provide an image forming method and an image forming apparatus which can stably obtain a high quality image for a long period of time without causing abrasion and damage of a photoreceptor and deterioration due to ozone even if image formation is repeated. Is provided.

As a result of intensive studies, the present inventors have found that a combination of a photoreceptor having inorganic particles in the uppermost layer to impart mechanical strength and a charger structure capable of effectively preventing ozone deterioration of the photoreceptor. The present invention has been found out.

The inorganic particles contained in the outermost surface layer of the electrophotographic photosensitive member of the present invention are hard particles having a Mohs hardness of 5 or more because they need to increase the film strength and have strength themselves. It is assumed that the performance will not be adversely affected.

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 diameter 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 μm.
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.

The inorganic particles being substantially spherical means that the surface shape can be distinguished by an electron microscope (diameter 1 to 10 mm).
When expanded to, the particles are not considered to have an indefinite shape, but are considered to be spherical with the ratio of major axis / minor axis less than 2.0. In that case, the wear coefficient of the surface of the photoconductor can be reduced. These effects are obtained by using the organic fine particles that have been conventionally used, that is, 0.
It cannot be expected for organic particles having a diameter of 05 μm or less. 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 tridecylbenzene sulfonyl titanate and bis (dioctyl pyrophosphate) oxyacetate titanate. 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 include undecyl acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid,
Long-chain fatty acids such as pentadecanoic acid, stearic acid, heptadecanoic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, and arachidonic acid are mentioned, and their metal salts are zinc, iron, magnesium, aluminum, calcium, sodium, lithium. Salts with metals such as.

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 photoconductor, and silica particles having low hygroscopicity and few active hydroxyl groups on the surface are preferably used. To be

In the present invention, these inorganic particles are contained in at least 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, based on 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 preferable. 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 substance (CGM) as a main component, and a photosensitive layer 6 formed by stacking in this order on the conductive support 1. 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. 1 (d), 1 (e) and 1 (h) respectively show a protective layer 5 on the photosensitive layer of FIGS. 1 (a), 1 (b) and 1 (c).
Are 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.

Of 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), 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 has a layer structure composed of so-called plural charge transport layers containing a charge transport substance (CTM) in the protective layer. Things are more preferable. 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.

The charging means is typically a corona discharge charger using a corotron, scorotron electrode or the like, and the shield member of the charger is a plate-shaped conductive member arranged so as to surround the band electrode. It is a member.

The image exposure means is a means for irradiating the photoconductor with image exposure light such as an LED array and a laser beam, as well as slit exposure used in a normal analog copying machine. Further, the developing means broadly refers to the developing means based on the electrophotographic developing method regardless of whether it is a single component or the two components, and the transferring means or the photoconductor cleaning means also broadly refers to the means attached to the apparatus to perform these functions. . In practice, after the transferring means, there is usually a separating means for peeling the transfer material from the photosensitive member.

The film strength of the photoreceptor can be measured by using a HEIDON-18 type surface property measuring device (manufactured by Shinto Scientific Co., Ltd.). That is, a vertical load of 200 g is applied to the surface of the photoconductor through a hemispherical diamond needle having a tip radius of 0.3 mm, the needle is moved at a speed of 10 mm / sec to make a scratch, and the depth of the scratch is measured by a laser microscope. (Lase
(made by rtec), and the depth (μm) was defined as the film strength.

Examples of the charge generating substance (CGM) contained in the photosensitive layer 6 of each of the photoreceptors shown in FIGS. 1A to 1F 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. The formation takes place.

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

[0042]

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(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.)

[0044]

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(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.
It is. )

[0046]

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(Wherein Y is a substituted or unsubstituted phenyl group,
It represents a naphthyl group, a pyrinyl group, a fluorenyl group, 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. )

[0048]

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(In the formula, Ar ₈ , Ar ₉ , Ar ₁₀ and Ar ₁₁ each represent a substituted or unsubstituted aromatic hydrocarbon group or 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.

[0050]

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[0051]

[Chemical 6]

[0052]

[Chemical 7]

[0053]

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[0054]

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[0055]

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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 is polyester resin, polystyrene resin, methacrylic resin, acrylic resin. , 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, Silicone resin, epoxy resin, silicone-alkyd resin, phenol resin,
Examples thereof include polysilane resin and polyvinyl carbazole.

The binder resin contained in the uppermost layer of each of the photoreceptors shown in FIGS. 1 (a) to 1 (f) is preferably resistant to mechanical impact and has high abrasion resistance, and does not impair electrophotographic performance. Things are good. Preferred binder resins include polycarbonate resins having a structural unit represented by the following general formula (I), (II), (III) or (IV).

[0058]

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(In the formula, R _{1 to} R ₈ are hydrogen atoms, halogen atoms, substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups or aryl groups, and Z is 4 to 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. )

[0060]

[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.)

[0062]

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

[0064]

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(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 a solvent or a 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. These solvents can be used alone or as a mixture of two or more solvents.

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.

The charge transport layer is formed by dissolving the above charge transport substance and the binder resin in an appropriate solvent, and coating and drying the solution. The mixing ratio of the charge transport material and the binder resin is preferably 10: 1 to 1:10 by weight.

The thickness of the charge transport layer is preferably 5 to 50 μm, particularly 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.

Next, as the electroconductive support of 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.

FIG. 2 shows an image forming apparatus using the present invention, and the present invention will be described further by using the image forming apparatus.

In forming an image, the photoconductor 10 starts rotating in the clockwise direction and an electrostatic latent image is formed on the surface of the photoconductor by the image exposure light from the image exposure means 12. The image information to be written is based on the information provided from a document reading unit (not shown), and the photoconductor is the charger 1.
1 uniformly charges before image exposure.

The electrostatic latent image on the surface of the photoconductor is developed by the developing means 13 to form a toner image. The toner image is transferred by the transfer unit 15 onto the transfer paper (transfer material) supplied from the paper supply unit 17 at the same timing. The transfer paper peeled off from the photoconductor by the separating means 16 carries a toner image and is conveyed to the fixing means 20 by the conveying means 19 to fix the toner image and then discharged from the inside of the image forming apparatus.

After the transfer paper is separated from the photosensitive member, the toner and the like remaining on the surface are removed by the cleaning means 21, and thereafter, the process of charging and image exposure is repeated for the next image formation.

By repeating this, a large number of images are formed. In this process, a large amount of ozone is generated due to the discharge in the vicinity of the discharge type charger, which is the charging means 11, and the concentration becomes 0.5 ppm or more. . This causes the surface of the photoconductor to be decomposed or deteriorated, resulting in deterioration of the performance of the photoconductor.
However, by devising the structure of the band electrode 11 as in the present invention, the air inside the machine is reduced to 0.1 m ³ / by means of the exhaust fan 32 or the like.
It was found that the performance deterioration was extremely small if the material was discharged at a speed of min or more.

In FIG. 2, 30 is an exhaust means. The charger 11 of the present invention will be described with reference to FIG.

FIG. 3 shows a scorotron charger used in the present invention, and 112 is a grit electrode for uniformly charging the photosensitive member 10. In the drawing, a plate-shaped shield member 114 is surrounded on three sides around the linear strip electrode 111 which is perpendicular to the paper surface except for the photoconductor side. In the charger according to the present invention, the shield member 11
4 has an opening 113, and the air flow is a mechanism that flows out of the opening from the photoconductor side through the inside of the charger. A guide plate, indicated at 31 in FIG. 2, is attached to create the flow.

As a discharging method, there is a method in which the duct 35 and the fan 32 are used to directly exhaust air from the opening on the back surface of the charger as shown in FIG. 4, but usually the exhaust fan provided on the machine wall shown in FIG. Many exhaust air,
In this case, it is preferably 0.5 m ³ / min or more.

In addition to the problem of fatigue deterioration of the photoconductor, there is a problem of environmental hygiene. The ozone concentration in the air discharged outside the machine is 0.05 ppm or less, preferably 0.02 ppm
The following is good. Therefore, for example, a platinum-rhodium alloy lining is used as ozone decomposing means on the shield member of the charger, or the ozone decomposing filter 3 is provided in the air flow discharge path.
It is desirable to provide a disassembling means such as providing 3.

As the ozone decomposer, Pt, Ni,
There are metal powders such as Co, Cu, Fe, Pd, and Rh or their composites, and Mn, Cu, Pb, Ni, Mo, and T.
There are metal oxides such as i, V, Pt, Ag, W and Zn.
Further, the ozone adsorbent includes activated carbon, alumina, silica, glass and the like.

These substances may form an ozone decomposing layer or a filter in the form of particles, or an ozone decomposing layer or a filter may be provided by plating, vapor deposition, sputtering, etc., and dispersed in a binder such as polyvinyl alcohol or cellulose resin. You may apply and process what was contained.

The present invention is a copier, laser printer, LE.
The present invention can be applied to general electrophotographic image forming apparatuses such as D printers and liquid crystal shutter type printers, but also displays, recording, light printing, plate making, which apply electrophotographic technology.
It can be widely applied to devices such as facsimiles.

[0084]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto. In the text, “parts” means “parts by weight”.

(1) Preparation of Photoreceptor Photoreceptor 1 Polyamide resin CM-8000 (manufactured by Toray Industries, Inc.) 30
900 g of methanol and 100 ml of 1-butanol
It was put in the mixed solvent of and heated and dissolved at 50 ° C. After cooling to room temperature, use this liquid to obtain an outer diameter of 80 mm and a length of 35.
An intermediate layer having a thickness of 0.3 μm was formed by dip coating on a 5.5 mm aluminum drum.

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

Then, 150 g of Exemplified Compound T-10
And BPZ type polycarbonate resin Panlite TS-20
100 g of 50 (manufactured by Teijin Chemicals Ltd.) was dissolved in 1000 ml of dichloromethane. Using this solution, a charge transport layer having a thickness of 20 μm was formed on the charge generation layer by dip coating.

Thereafter, 150 g of Exemplified Compound T-10
And BPZ type polycarbonate resin Panlite TS-20
50 g (manufactured by Teijin Kasei Co., Ltd.) and 30 g of the inorganic particles A1 shown in Table 1 were added to a solution prepared by dissolving the mixture in 1000 ml of dichloromethane, and dispersed in an ultrasonic bath for 20 minutes. Using this solution, a circular amount regulating type coating machine was used to form a surface protective layer having a thickness of 5 μm on the above charge transport layer by means of the circular amount regulating type coating machine.

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.

[0090]

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Photoconductors 2 and 3 (for Examples) and photoconductor 4
~ 6 (Comparative Example) Photosensitive members 2 to 6 were obtained in the same manner as the photosensitive member 1 except that the kinds of inorganic particles and the addition amount thereof were as shown in Table 1.

All the inorganic particles shown in Table 1 were hydrophobized with a theoretical amount of trimethylsilylmethoxysilane.

The film strength of each photoconductor is set to HEIDON-1.
It measured using the 8 type surface property measuring device (made by Shinto Scientific Co., Ltd.).
That is, a vertical load of 200 g is applied to the surface of the photoconductor through a hemispherical diamond needle having a tip radius of 0.3 mm, the needle is moved at a speed of 10 mm / sec to make a scratch, and the depth of the scratch is measured by a laser microscope. (Manufactured by Lasertec) was measured, and the depth (μm) was taken as the film strength and shown in Table 1.

[0094]

[Table 1]

Performance Evaluation A modified machine provided with a guide plate (31 in FIG. 2) for directing the air flow from the photoconductor side to the back opening of the charger on the side of the charger of Konica U-BIX4155 manufactured by Konica Corporation. Example in which the photoconductors shown in Table 1 were mounted in the order shown in Table 2 on the modified machine, and the air discharge amount of the fan for exhausting the machine (with an ozone decomposing filter for activated carbon) was changed as shown in Table 2. Nine types of electrostatic characteristic tests and image forming tests of 1 to 5 and Comparative Examples 1 to 4 were performed.

Further, the position of the in-machine exhaust fan is moved downward (moved from 30 to 30 'in FIG. 2) so that the air flow is directed from the charging device to the photoconductor side. The electrostatic characteristic test and the image forming test of Example 6 were performed with the photoconductor A2 of No. 1 mounted and the air discharge amount set to 0.5 m ³ / min in Table 2.

(2) Electrostatic Characteristic Test Under normal temperature and normal humidity, an original having half a solid black area with a reflection density of 1.3 and half a white area with a reflection density of 0.0 was used, and an electrometer was placed at the developing position. , Charging and exposure are repeated 100,000 times, and the difference between the initial potential and the potential after 100,000 times (| ΔV
_B |) and the blank sheet potential difference (| ΔV _W |) and the residual potential difference (| ΔV _R |) were measured, and the results are shown in Table 2.

The difference in residual potential was measured at the first and 10th times.
In the tenth measurement, it was determined from the difference between the potentials when the charger was turned off and one extra rotation was performed.

(3) Image Evaluation Using an original document (coverage 10%) having a solid black with a reflection density of 1.3, a halftone of 0.3, and a white paper part of 0.0 under normal temperature and normal humidity, respectively. A copy test was conducted 100,000 times, and maximum density, fog, sensitivity, and sharpness were visually evaluated, and the results are shown in Table 2.

[0100]

[Table 2]

From Table 2, in each of the examples, the potential fluctuation is small and the copy image is excellent, but in the comparative example, the sensitivity and the fog are decreased due to the abrasion and damage of the photoreceptor, and the electrophotographic performance is deteriorated due to the cleaning failure. It can be seen that any one of them has occurred and is not practical.

[0102]

As is apparent from the above description, according to the image forming method of the present invention, there is no image deterioration due to friction, damage and ozone deterioration of the photoconductor in the process of repeatedly forming an image, and the image quality is high for a long time. It is possible to obtain the effects such as stable production.

[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 configuration cross-sectional view showing an example of an image forming apparatus using the present invention.

FIG. 3 is a sectional view of a scorotron charger according to the present invention.

FIG. 4 is a schematic diagram illustrating a device that directly exhausts air from an opening on the back of the charger by a duct and a fan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive support 2 Intermediate layer 3 Charge transport layer (CTL) 4 Charge generation layer (CGL) 5 Protective layer 6 Photosensitive layer 10 Photoconductor 11 Charging means charger 111 111 Electrode 112 Grit electrode 113 Opening 114 Shield member 13 developing device as a developing means 15 transfer device as a transferring means 20 fixing device as a fixing means 21 cleaning device as a cleaning means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 21/00 540 G03G 21/00 540

Claims (4)

[Claims] 1. An image forming process for forming a large number of images by repeating the steps of charging a photoconductor, developing an image-exposed toner with a toner, transferring a toner image onto a transfer body, and cleaning the photoconductor after the transfer. In the method, the uppermost layer of the photoreceptor contains inorganic particles having a Mohs hardness of 5 or more, and the film strength of the uppermost layer is 20 using a diamond needle having a tip radius of 0.3 mm.
The depth of scratches when a vertical load of 0 g is applied is 0.1 to 1.0.
μm, the shield member of the charger for charging the photoconductor is a discharge type charger having an opening through which an air flow flows, and the air inside the image forming apparatus is 0.1
An image forming method characterized in that exhaust is performed at an amount of m ³ / min or more. 2. The photoconductor has a structure in which a plurality of layers containing a charge transport material are laminated on a charge generation layer, and the uppermost layer is a layer containing a charge transport material. 1. The image forming method described in 1. 3. The image forming method according to claim 1, wherein the inorganic particles contained in the uppermost layer of the photoreceptor have a volume average particle diameter of 0.05 to 2 μm. 4. A photoconductor, a photoconductor charging unit, an image exposing unit,
Toner developing means, means for transferring a toner image onto a transfer body,
In an image forming apparatus for forming a large number of images having a photosensitive member cleaning means, the uppermost layer of the photosensitive member contains inorganic particles having a Mohs hardness of 5 or more, and the film strength of the uppermost layer has a tip radius of 0.3 mm. 200 with diamond needle
Depth of scratch when vertical load of g is 0.1-1.0μ
m, the photoconductor charging means is a discharge type charger having a shield member having an opening through which air flows, and the airflow passes from the photoconductor side through the inside of the charger to the shield member opening of the charger. An image forming apparatus characterized in that the image is discharged from the image forming apparatus.