JPH08286408A - Electrophotographic photoreceptor, electrophotographic device and device unit - Google Patents

Abstract

PURPOSE: To obtain a high durability electrophotographic photoreceptor not causing defective cleaning, an electrophotographic device and a device unit each using the photoreceptor. CONSTITUTION: This electrophotographic photoreceptor has a photosensitive layer 6 on the electrically conductive substrate 1 and contains org. particles and silica particles having 0.05-2μm volume average particle diameter and 0-20J/g variation ΔH of absorbed heat energy in the range of 40-200 deg.C by differential scanning calorimetry in an environment at 80% relative humidity in the top layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, an electrophotographic apparatus and an apparatus unit, and more particularly to an electrophotographic photoreceptor having excellent durability, an electrophotographic apparatus and an apparatus unit using the photoreceptor.

[0002]

2. Description of the Related Art Generally, in order to form an image by an electrophotographic method, a toner image is formed on a surface of a photoconductor by charging, imagewise exposing and developing the toner image, and the toner image is transferred and fixed on a transfer material to form an image. After the transfer, the photosensitive member after the transfer is cleaned and removed of residual toner, and is repeatedly used for a long period of time.

Therefore, the photoconductor has, of course, electrophotographic performance such as charging potential, sensitivity, dark decay and residual potential characteristics.
It is also required to have good physical properties such as printing durability, abrasion resistance, and moisture resistance during repeated use, and resistance to ozone and image exposure generated during corona discharge.

On the other hand, as an electrophotographic photosensitive member, an inorganic photoconductive photosensitive member using amorphous silicon, selenium, cadmium sulfide, etc. has been widely used as a conventional electrophotographic photosensitive member. Organic photoconductive photoreceptors (hereinafter simply referred to as organic photoreceptors) that are excellent and have a high degree of freedom in selection according to the purpose have become the mainstream.

Fatigue deterioration due to repeated use of these electrophotographic photosensitive members is caused by the steps of transferring a toner image formed on the photosensitive member onto a transfer material, separating and cleaning residual toner on the photosensitive member after transfer. It is said that the surface of the photosensitive layer is rubbed and damaged due to the rubbing, and the surface of the photosensitive body is decomposed and deteriorated in each step such as charging, imagewise exposure and charge removal.

Therefore, in order to prevent fatigue deterioration of the photoreceptor, improvement of the surface of the photosensitive layer is an important issue. In particular, the photosensitive layer of the organic photoconductor is softer than the inorganic photoconductor, and since the photoconductive substance is organic, fatigue deterioration is large during repeated use of the photoconductor, and the improvement of the surface of the photoconductive layer is Becomes more important.

Therefore, in JP-A-56-117245, JP-A-63-91666 and JP-A-1-05171, silica particles are contained in the outermost surface layer of the photoconductor to improve the mechanical strength of the photoconductor surface. It is described that it is large and the durability can be improved. Furthermore, in JP-A-57-176057, JP-A-61-117558, JP-A-3-155558 and the like, hydrophobic silica particles obtained by treating the silica particles with a silane coupling agent are disclosed in It is described that by containing it in the outermost surface layer, the mechanical strength of the photoconductor is increased and the lubricity is imparted to obtain a photoconductor having higher durability.

However, the photoreceptor using such silica particles causes cleaning failure when repeatedly used and causes problems such as fog and black streaks. On the other hand, it is known that addition of organic particles is effective for such poor cleaning, but the organic particles lack mechanical strength, and a highly durable photoreceptor cannot be obtained.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly durable electrophotographic photosensitive member without causing cleaning failure. Another object of the present invention is to provide an electrophotographic apparatus and an apparatus unit which can repeatedly and stably form an image by using the photoconductor without causing cleaning failure and exchanging the photoconductor. Especially.

[0010]

The above objects of the present invention are achieved by the following constitutions.

1) In an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the outermost surface layer of the electrophotographic photosensitive member is adjusted to 40 ° C. in a differential scanning calorimetry in which humidity is controlled in an environment of relative humidity of 80%. An electrophotographic photosensitive material containing silica particles and organic particles having an endothermic energy change amount ΔH of 0 to 20 joules / g in the range of 200 ° C. or less and a volume average particle diameter of 0.05 μm or more and 2 μm or less. body.

2) The electrophotographic photosensitive member according to 1 above, wherein the organic particles are silicone particles.

3) The electrophotographic photosensitive member described in 1 above, wherein the organic particles are fluorine atom-containing resin particles.

4) The electrophotographic photosensitive member described in 1, 2, or 3, wherein the silica particles are surface-treated with a fluorine-containing silane coupling agent.

5) A latent image forming means for forming an electrostatic latent image on the photoconductor according to the above item 1, a developing means for developing the electrostatic latent image formed on the photoconductor into a toner image. Electrophotography comprising a transfer means for transferring a toner image on the photoconductor obtained by visualization to a transfer material, and a cleaning means for cleaning the toner remaining on the photoconductor after the toner image is transferred. apparatus.

6) The electrophotographic apparatus according to 5, wherein the cleaning means is an elastic blade cleaning means.

7) The cleaning blade of the cleaning means is 5 to 5 in the counter direction with respect to the photosensitive member.
7. The electrophotographic apparatus as described in 6 above, which is cleaned by pressing with a pressing force of 50 (g / cm).

8) The photoconductor according to the above item 1, charging means for uniformly charging the photoconductor, developing means for visualizing an electrostatic latent image on the photoconductor, and visual image on the photoconductor. At least one of a transfer means for transferring the converted toner image onto a transfer material, a charge removing means for removing charges on the photoconductor after the transfer, and a cleaning means for cleaning the residual toner on the photoconductor after the transfer; Is integrally supported and is detachably attached to the main body of the apparatus.

9) The apparatus unit according to the above 8, wherein an elastic cleaning blade is used as the cleaning means, and at least the cleaning blade and the photosensitive member are integrally supported and are detachably attached to the apparatus main body.

The outermost surface layer of the photoconductor of the present invention means a layer constituting the outermost surface when the electrophotographic photoconductor of the present invention is manufactured. For example, a protective layer provided on the photosensitive layer. ,
Alternatively, when the protective layer is not provided, it is the photosensitive layer forming the outermost surface, and among them, it is preferably the charge transport layer (CTL). The protective layer preferably further contains a charge transport substance (CTM) in addition to the silica particles of the present invention. The outermost surface layer in the present invention is the silica particles of the present invention and CTM optionally contained, and other additives dispersed in a binder resin (described later),
It is provided by means such as coating.

The silica particles of the present invention will be described. The silica particles of the present invention have a volume average particle diameter of 0.05 μm or more and 2 μm or less, preferably 0.1 μm or more and 2 μm or less, and have a sharp particle size distribution.

The volume average particle diameter of the silica particles of the present invention is 0.05.
If it is less than μm, the mechanical strength required for the surface of the photosensitive layer cannot be obtained, and it is easily worn and damaged during the repeated image formation process, and the electrophotographic performance is deteriorated. On the other hand, if it exceeds 2 μm, the surface roughness of the photosensitive layer becomes large, and cleaning failure occurs.

Further, the silica particles are preferably substantially spherical, and particularly preferably substantially spherical with a ratio of major axis / minor axis of less than 2.0, and the term “spherical” as used herein means an electron microscope. It is shown that the particles expanded 10,000 times are spherical rather than amorphous. In that case, it is possible to reduce the friction coefficient of the surface of the photosensitive layer, and it is possible to prevent reversal (blade flipping) of the elastic cleaning blade, which has been a problem in the related art. In addition, it is preferable that the silica particles have a sharp particle size distribution, in which case the occurrence of film defects due to the inclusion of coarse particles on the surface of the photosensitive layer or the agglomeration of small particles is prevented.

As a method for producing the silica particles of the present invention, a chemical flame CVD method (CVD: Chemical Valpor Deposition) is preferable. This method is a method of producing a high-temperature flame by burning an oxygen-hydrogen mixed gas or a hydrocarbon-oxygen mixed gas, in which a gas phase reaction is caused to produce, and as an example, chlorosilane gas is used as the mixed gas. There is a method of obtaining silica particles by performing a gas phase reaction in a high temperature flame.

The silica particles according to the present invention are the chemical flame CVD.
It is preferably produced by a method, but among them, it is preferable to introduce the metal silicon powder into the mixed gas and explosively combust and react.

Details of this production method are described in, for example, JP-A-60-25560.
No. 2, JP-A-5-193908, No. 5-193909, and No. 5-139910
No. 5-139928, No. 5-196614, and No. 6-107406.

In the manufacturing methods described in the above-mentioned 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, combustible gas such as LPG and supporting gas such as oxygen gas are introduced into the 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-mentioned manufacturing method, it is possible to obtain high-purity silica fine particles having a sharp particle size distribution, and it is possible to manufacture by varying the particle size distribution in a wide range according to the purpose. .

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

The differential scanning calorimetry (DSC) of the silica particles of the present invention is a method in which the energy necessary to cancel the temperature difference between a thermally stable standard substance and a sample heated at a constant rate is added. , DSC peak area is proportional to the amount of endotherm, it can be quantified according to the following formula.

M · ΔH = K · A Here, M is the mass of the sample, ΔH is the amount of energy change per unit mass of the sample, K is the device constant, and A is the peak area. The silica powder was left to stand in an environment of 80% relative humidity for 24 hours to control the humidity. After that, the sample was stored in a sealed container under the same conditions until the DSC measurement, and the measurement was performed within 60 minutes after the completion of the humidity control.

The measurement conditions of DSC used in the present invention are shown below.

Equipment: Differential running calorimeter DSC-20 Thermal controller SSC-580 (Seiko Denshi Kogyo) Measuring conditions: Measuring temperature 35-300 ° C Temperature rising rate 10 ° C / min (relative humidity 80%) Measuring environment Air Still atmosphere The ΔH of the silica particles according to the present invention is 0 to 20 joules / g.
Is preferred, but more preferably 0.1 to 10 joules /
g.

The silica particles used in the present invention are, for example, titanium coupling agents, silane coupling agents,
Hydrophobic silica particles treated with a hydrophobizing agent such as an aluminum coupling agent, a polymeric fatty acid or a metal salt thereof are more preferable.

The silane coupling agent used in the present invention is not particularly limited, but a fluorine-containing silane coupling agent is preferable.

Specific examples of the fluorine-containing silane coupling agent preferably used in the present invention are shown below.

[0037]

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These coupling agents may be mixed with a binder resin and used, but it is preferable to use silica particles which have been surface-treated with a coupling agent in advance. As a result, the affinity between the particle surface of the present invention and the binder resin is increased, and the dispersibility and adhesiveness can be improved.

The amount of the coupling agent used is 0.1 to 100 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the particles.

Since the hydrophobic treatment film applied to the silica particles is a monomolecular layer or a thin layer close thereto, the amount of impurities and the volume average particle diameter of the hydrophobic silica particles are substantially the same as those before the hydrophobic treatment. The same as that of the silica particles.

In the present invention, these silica particles are contained at least in the outermost surface layer of the electrophotographic photosensitive member together with the binder. The ratio of the silica particles in the outermost surface layer is usually 0.1% by weight or more and 200% by weight to the binder. Hereinafter, it is preferably used in an amount of 1% by weight or more and 100% by weight or less.

The organic particles used in the present invention are preferably organic fine particles having an average particle size of 0.05 to 10 nm. These organic fine particles include fluororesin fine particles, silicone resin fine particles, olefin resin fine particles, and other polymer fine particles. Is mentioned.

As the fluororesin, polytetrafluoroethylene (PTFE), polytrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyfluoroalkyl vinyl ether, polychlorotrifluoroethylene, polyhexafluoropropylene, polydifluorodichloroethylene or The copolymer of this is mentioned.

Examples of silicone resins include organopolysiloxanes such as methylhydrogenpolysiloxane, dimethylpolysiloxane, methoxypolysiloxane, methylphenylpolysiloxane and cyclohexylpolysiloxane.

Examples of the olefin resin include polyethylene, polypropylene, polybutene and polyhexene.

Other resins used in the present invention include polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, acrylic polymers, polystyrene and copolymers thereof.

In the present invention, these organic particles are contained together with silica particles and at least the outermost surface layer of the electrophotographic photosensitive member together with a binder. The ratio of the organic particles in the outermost surface layer is usually 0.1 with respect to 100% by weight of the silica particles. 100% by weight or more
Hereinafter, it is preferably used in an amount of 1% by weight or more and 50% by weight or less.

The photosensitive layer of the electrophotographic photosensitive member of the present invention containing the silica particles and the organic particles in the outermost surface layer may be an inorganic photosensitive member using selenium, amorphous silicon, cadmium sulfide or the like. , Preferably an organic photoreceptor containing an organic charge generating substance (CGM) and a charge transporting substance (CTM). The layer structure of the organic photoreceptor is shown in FIG.

In FIG. 1A, the intermediate layer 2 is formed on the 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.

1 (d), (e) and (f) respectively show a protective layer 5 on the photosensitive layer of FIG. 1 (a), (b) and (c).
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 the protective layer 5 is further laminated on the photosensitive layer as shown in (d), (e) and (f), and In which the silica particles of the present invention and organic particles are contained.

The protective layer, when provided, is composed of at least a resin, the silica particles of the present invention, and organic particles, but it is more preferable to include a charge transport 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. 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 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.

[0056]

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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.)

[0058]

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(In the formula, R ₃ and R ₄ each represent a substituted or unsubstituted aromatic hydrocarbon group, a heterocyclic group or an 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. )

[0060]

[Chemical 4]

(In the formula, Y is a monovalent substituted or unsubstituted phenyl group, naphthyl group, pyrenyl 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. )

[0062]

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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 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.

[0064]

[Chemical 6]

[0065]

[Chemical 7]

[0066]

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[0067]

[Chemical 9]

[0068]

[Chemical 10]

[0069]

[Chemical 11]

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 can be 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.

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 ratio of the charge generating substance to the binder resin in the charge generating layer is 1: 5 to 5: by weight.
1, especially 1: 2 to 3: 1 are preferred. The film thickness of the charge generation layer is preferably 5 μm or less, and particularly preferably 0.05 to 2 μm.

The charge-transporting layer is formed by dissolving the above-mentioned charge-transporting substance and the binder resin in a suitable solvent, and coating and drying the solution. The mixing ratio of the charge transport material and the binder resin is preferably 3: 1 to 1: 3 by weight ratio, and particularly preferably 2: 1 to 1: 2.

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.

When the outermost surface of the present invention is formed of a protective layer,
The protective layer is formed by dissolving and dispersing the resin, the silica particles and the organic particles of the present invention together with a solvent, and coating the solution on the photosensitive layer. In this case, it is preferable to add a charge transport material (CTM) to the protective layer. Resin and CTM in protective layer
The ratio is preferably 3: 1 to 1: 3. Especially 2: 1 to 1: 2
The thickness of the protective layer is preferably 0.2 to 10 μm. If it is less than 0.2 μm, it is difficult to obtain the effect of the present invention. On the other hand, if it exceeds 10 μm, the resolution of the image deteriorates due to light scattering by the silica particles in the protective layer. Further, the sensitivity may decrease and the residual potential may increase. A particularly preferred range is 0.4 to 5 μm.

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.

Next, as a coating processing method for producing 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 a binder 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, further, a coating is provided between the support and the undercoat layer for compensating for surface defects of the support, 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,
Particularly, 10 to 30 μm is preferable.

The shape of the support may be drum-shaped, sheet-shaped or belt-shaped, and it is preferable that the shape is optimal 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 denotes a photosensitive drum which is an image carrier, and is coated with an OPC photosensitive layer on the drum, 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 image forming process of the second color is started, and the scorotron charger 12 performs uniform charging again to form a latent image of the second color. 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 photoconductor drum 10 and conveyed to the fixing device 20, and 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.

The 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 exposing means irradiates the photoconductor with reflected light or transmitted light from the original document, or a sensor reads the original document to convert it 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 printer for a facsimile, the image exposure means 13 provides exposure for printing received data.

[0099]

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

Examples 1 to 10 and Comparative Examples 1 and 2 <Preparation of Photoreceptor for Example 1> Copolymer type polyamide resin “Amilan C” on an aluminum drum of φ80 mm.
M-8000 "(manufactured by Toray Industries, Inc.) 1.5 parts by weight is dissolved in a mixed solvent of 90 parts by volume of methanol and 10 parts by volume of butanol to form an intermediate layer having a thickness of 0.3 μm by dip coating. Formed. Next, 0.8 parts by weight of polyvinyl butyral resin "ESREC BL-S" (manufactured by Sekisui Chemical Co., Ltd.) was dissolved in a mixed solvent of 80 parts by weight of methyl ethyl ketone and 20 parts by weight of cyclohexanone, and the following structural formula was added to the resulting solution. 4 parts by weight (CGM / binder amount ratio of 5.0) of CGM1 are mixed and dispersed in the intermediate layer to form a carrier generation layer having a thickness of 0.2 μm after drying and coating. Was formed.

[0101]

[Chemical 12]

Next, as a binder, a polycarbonate resin “UPILON Z300” (manufactured by Mitsubishi Gas Chemical Co., Inc.) 15
10 parts by weight of the compound (T-2) shown in Chemical formula 6 as a carrier transporting substance, and 0.25 parts by weight of a hindered phenolic antioxidant "Irganox 1010" are dissolved in 100 parts by volume of methylene chloride. Coating solution is applied onto the carrier generating layer by dip coating, and the film thickness after drying is 2
A 5 μm first carrier transport layer was formed.

Further, as a binder, a polycarbonate resin "Iupilon Z800" (manufactured by Mitsubishi Gas Chemical Co., Inc.)
5 parts by weight, 1.2 parts by weight of silica particles shown in Table 1, 0.6 parts by weight of organic particles, 1 part by weight of the compound (T-4) shown in Chemical formula 6 as a carrier transporting substance, hindered phenolic antioxidant "IRGA Knox 1010 "0.025 parts by weight is dissolved and dispersed in 100 parts by volume of 1,2-dichloroethane to apply a coating solution on the first carrier transport layer using a circular amount control type coating machine, and then dried. A second carrier transport layer having a film thickness of 1 μm was then formed to obtain a photoconductor for Example 1 shown in Table 1.

<Photoreceptors for Examples 2 to 9 and Comparative Examples 1 and 2
Preparation of Photoreceptor for Use> Thickness of second carrier transport layer of photoreceptor for Example 1, type and volume average particle size of silica particles, energy change amount ΔH in differential thermal analysis, ratio to binder (% by weight) Also, the photoreceptors for Examples 2 to 7 and the photoreceptors for Comparative Examples 1 to 4 were obtained in the same manner as the photoreceptor 1 except that the kind and the ratio (% by weight) of the organic particles were changed as shown in Table 1.

<Preparation of Photoreceptor for Example 10> The surface of silica particles used in the preparation of the photoreceptor for Example 3 was surface-treated with the compound (1) of Chemical formula 1, which is a fluorinated silane coupling agent. A photoconductor for Example 8 was made in the same manner as the photoconductor for Example 3 except for the above.

[0106]

[Table 1]

Analog copying having the steps of charging, image exposure, development, transfer, charge removal and cleaning, in which at least the photosensitive member and the cleaning means are unitized into a unit of the photosensitive member obtained as described above. Machine "Konica
U-BIX4145 "(manufactured by Konica Corporation) and subjected to an image forming test for each photoconductor at room temperature and normal humidity (20 ° C., 60%).
The worn film thickness was measured after the copying of 0,000 times.

1) Image Evaluation The photoconductors were sequentially attached to the copying machine, and images were printed 100,000 times using a halftone original. At this time, a scorotron charger was used as the charger, and an image was formed on the photoreceptor under a constant charging condition of -750 V by grid control.

The image forming test was conducted 100,000 times, and the presence or absence of background fog due to poor cleaning, the presence or absence of streak failure due to the cleaning blade turning over, the image sharpness, etc. were visually observed, and the results are shown in Table 2. It was shown to.

2) Measurement of Potential Fluctuation Amount of black paper potential (Vb) and castle paper potential (Vw) before and after the 100,000 times image forming test are measured, and from the difference ΔVb and ΔVw, each exposure before and after image formation. The amount of body potential fluctuation was determined, and the results are shown in Table 2.

An original having half a solid black area with a reflection density of 1.3 and a solid white area with a reflection density of 0.0 was used as the original for measurement, and was -750 V by the scorotron charger.
After charging, the electrostatic latent image formed by image exposure from the original is measured by an electrometer placed at the position of the developing device to measure the black paper potential (Vb) and the white paper potential (Vw). I did it.

[0112]

[Table 2]

From Table 2, in the examples using the respective photoconductors for the examples, the potential fluctuations such as the black paper potential and the white paper potential and the film thickness loss are small in the process of repeatedly forming an image, and there is no background fog or streak failure. A clear image can be obtained, but in each comparative example using the photoconductor for the comparative example, a background fog or a streak failure occurs in the process of repeated image formation, and the film thickness wear is large, so that a good image cannot be obtained. I understand.

Example 11 and Comparative Example 5 <Production of Photoreceptor for Example 11 and Photoreceptor for Comparative Example 5> φ
An intermediate layer was formed on an 80 mm aluminum drum in the same manner as the photoreceptor for Example 1. Next, 6 parts by weight of the carrier-generating substance 1 used in the photoreceptor for Example 1 and a polycarbonate resin "Iupilon Z30" as a binder resin were used.
0 "20 parts by weight is mixed with 100 parts by volume of 1,2-dichloroethane and dispersed by using a sand mill, and the resulting dispersion is used as a carrier transporting compound represented by Chemical formula 11 (T-
4) 20 parts by weight, antioxidant "Irganox 101
0 "0.5 part by weight was mixed and dissolved, and further 4 parts by weight of inorganic particles (Admafine SO-C1) were mixed and dispersed to obtain a coating liquid. This coating solution was applied onto the intermediate layer by dip coating to form a photosensitive layer having a thickness of 23 μm after drying to obtain a photoconductor for an example.

On the other hand, a photoreceptor for Comparative Example 5 was prepared which was produced without using inorganic particles in the photoreceptor for Example 11.

Using the modified U-BIX4145 modified for positive charging, the photoconductors for Example 11 and Comparative Example 5 obtained as described above were sequentially mounted, and the positive charging method was used. An image forming test was performed 100,000 times in the same manner as in Example 1, and the image evaluation of the obtained image and the amount of change in each potential of the photoreceptor after 100,000 copies with respect to the initial white paper potential and black paper potential of the photoreceptor. And film thickness loss were measured, and the results are shown in Table 3.

[0117]

[Table 3]

From Table 3, the photoconductors for the examples showed a small amount of potential fluctuation, and a clear image without ground fog and streak defects was obtained, but the photoconductors for comparative examples all had ground fog and streak defects. However, a clear image could not be obtained.

[0119]

According to the present invention, a highly durable electrophotographic photosensitive member, an electrophotographic apparatus and an apparatus unit using the photosensitive member can be obtained without causing cleaning failure.

[Brief description of drawings]

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

FIG. 2 is a sectional view of the 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 10 Photosensitive Drum 11 Exposure Section Using Light Emitting Diodes 12 Scorotron Charger 13 Image Exposure Means 14 Developing device 17 Paper feed roller 18 Transfer roller 19 Separation brush 20 Fixing device 21 Paper ejection roller 22 Cleaning device 30 Removable cartridge in which image holding member, charging means, developing means and cleaning means are integrated

Claims (9)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the outermost surface layer of the electrophotographic photoreceptor comprises:
The endothermic energy change amount ΔH in the range of 40 ° C. or higher and 200 ° C. or lower in the differential scanning calorimetry controlled under the environment of 80% relative humidity is 0 to 20 Joules / g, and the volume average particle size is 0.
An electrophotographic photoreceptor comprising silica particles having a size of from 05 μm to 2 μm and organic particles. 2. The electrophotographic photosensitive member according to claim 1, wherein the organic particles are silicone particles. 3. The electrophotographic photoreceptor according to claim 1, wherein the organic particles are fluorine atom-containing resin particles. 4. The electrophotographic photoreceptor according to claim 1, wherein the silica particles are surface-treated with a fluorine-containing silane coupling agent. 5. A latent image forming means for forming an electrostatic latent image on the photoconductor according to claim 1, a developing means for developing the electrostatic latent image formed on the photoconductor into a toner image, Electrophotography comprising a transfer means for transferring a toner image on the photoconductor obtained by visualization to a transfer material, and a cleaning means for cleaning the toner remaining on the photoconductor after the toner image is transferred. apparatus. 6. The electrophotographic apparatus according to claim 5, wherein the cleaning unit is an elastic blade cleaning unit. 7. The cleaning blade of the cleaning means is 5 to 50 in the counter direction with respect to the photosensitive member.
7. The electrophotographic apparatus according to claim 6, wherein the electrophotographic apparatus is cleaned by pressing with a pressing force of (g / cm). 8. The photosensitive member according to claim 1, a charging unit for uniformly charging the photosensitive member, a developing unit for developing an electrostatic latent image on the photosensitive member, and a visible image on the photosensitive member. At least one of a transfer means for transferring the converted toner image onto a transfer material, a charge removing means for removing charges on the photoconductor after the transfer, and a cleaning means for cleaning the residual toner on the photoconductor after the transfer; Is integrally supported and is detachably attached to the main body of the apparatus. 9. The apparatus unit according to claim 8, wherein an elastic cleaning blade is used as the cleaning means, and at least the cleaning blade and the photoconductor are integrally supported and are detachably attached to the apparatus main body.