JPH08314174A - Electrophotographic photoreceptor, electrophotographic device and device unit - Google Patents

Abstract

PURPOSE: To improve the durability of an org. electrophotographic photoreceptor and to prevent the deterioration of the characteristics of a cleaning blade brought into press contact with the surface of the photosensitive layer of the photoreceptor by incorporating specified particles into the top layer of the photosensitive layer. CONSTITUTION: Two or more kinds of silica particles different from each other in specific gravity or two or more kinds of mutually different multiple metal oxide particles are incorporated into the top layer of the photosensitive layer 6 of an electrophotographic photoreceptor. In the case where a protective layer 5 is not dispose the top layer of the photosensitive layer 6 is the photosensitive layer 6 forming the top of the photoreceptor, preferably an electric charge transferring layer 3. It is especially preferable that a protective layer 5 is further laminated on the photosensitive layer 6 and the particles are incorporated into the layer 5. An electric charge transferring material is preferably incorporated into the layer 5. The rising of residual potential and the lowering of sensitivity can be prevented.

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.

A technique for making a binder into a high molecular weight material is well known in order to improve the mechanical strength of the outermost surface layer of the photoconductor. However, the high molecular weight binder has a large degree of entanglement of polymer chains and is applied. Since the viscosity of the liquid is large, it is difficult to apply and severe conditions are required for drying. Further, the residual solvent contained in the photoreceptor leads to an increase in potential (reduction in sensitivity) during repeated use, which is not preferable in terms of the characteristics of the photoreceptor.

Therefore, in JP-A-56-117245, JP-A-63-91666 and JP-A-1-205171, 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 the durability can be improved by increasing the value. 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, in recent years, there is a strong demand for further improvement in durability of the photoconductor, and in reality, it is difficult to say that the demand has been sufficiently met.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly durable electrophotographic photosensitive member which does not cause cleaning failure and does not deteriorate the characteristics of the cleaning blade pressed against the surface of the photosensitive member. is there. 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.

[0011]

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

[1] An electrophotographic photosensitive member characterized in that, in the photosensitive layer of the electrophotographic photosensitive member, the outermost surface layer contains any of the following particles.

(1) Two or more kinds of silica particles having different specific gravities (2) Two or more kinds of metal composite oxide particles different from each other [2] Two or more kinds of metal composite oxide particles are silicon atoms and silicon atoms. 2. The electrophotographic photosensitive member according to claim 1, which is a composite oxide particle of a metal atom other than the above.

[3] The electrophotographic photosensitive member according to claim 1, wherein the particles contained in the outermost surface layer have a volume average particle size of 0.05 µm or more and 5.0 µm or less.

[4] The outermost surface layer of the photosensitive layer has an electrophotographic photosensitive member containing any of the following particles, an electrostatic latent image forming means, a developing means, a transferring means, and an elastic blade cleaning means. Electrophotographic device.

(1) Two or more kinds of silica particles having different specific gravities (2) Composite oxide particles of two or more kinds of metals different from each other [5] An electron whose outermost surface layer of the photosensitive layer contains any of the following particles An electrophotographic photoreceptor of an electrophotographic apparatus having a photographic photoreceptor, an electrostatic latent image forming means, a developing means, a transfer means, and an elastic blade cleaning means, and at least one of the above means is unitized. Electrophotographic device unit.

(1) Two or more kinds of silica particles having different specific gravities (2) Composite oxide particles of two or more kinds of metals different from each other By adopting the above-mentioned constitution, the durability of the photoreceptor is improved. However, it was found that the wear of the cleaning blade, which proved to be a problem when using hard silica particles or the like, could be prevented.

In the present invention, the outermost surface layer of the photosensitive layer in the photoconductor is a photosensitive layer constituting the outermost surface when a protective layer is not provided, and among them, the charge transport layer (CT
L) is preferred. The protective layer preferably further contains a charge transport material (CTM) in addition to the silica particles of the present invention, the metal composite oxide particles, and the like. In general, the specific gravity of silica particles varies depending on the synthesis method, the degree of sintering and the degree of polymerization, and changes in the internal surface area. At the same time, the physical properties of the silica particle surface change. For example, silica particles having a low degree of polymerization, such as high-presica, have a specific gravity of 1.
It is as low as 6 and its surface is rich in silar groups and highly polar. Conversely, Admafine SO-C1 synthesized by the Ki phase method
Such silica particles have almost no internal specific surface area, high specific gravity of 2.2, low surface polarity, and high affinity with organic solvents. Sea hosters have a specific gravity of 1.8 and a value in between.

The reason why the surface characteristics of the photoconductor are improved by using these silicas having different specific gravities together is as follows.
It has not been completely clarified. In any case, the combined use changes the specific surface area of the silica particles, the dispersibility and the distribution width of hardness,
As a result, it can be held at an appropriate value. It should be noted that the mixing ratio of the silica particles having a difference in specific gravity of 0.2 or more is a low specific gravity silica: high specific gravity silica = 1 to 8: 9 by weight ratio.
It is desirable to mix about two.

On the other hand, the surface characteristics of the photoconductor are also improved by the complex oxide of different metals. Even in this case, the hardness and dispersibility of the particles change, but the optical properties of the outermost surface of the photoconductor may change due to the complex oxide having a different crystal structure, and the effect may be added. is there.

In order to form the composite oxide, it is preferable to simultaneously oxidize different metals in the Ki phase by the chemical flame CVD method. Specifically, JP-A-60-255602 and JP-A-5-19
No. 3908, No. 5-193909, No. 5-19391
No. 0, No. 5-196614, or JP-A-6-107.
It can be produced by the method described in No. 406.

The composite metal oxide particles may be in the form of a mixture with each other, or one of them may be dispersed in the other.

The particles added to the outermost surface layer of the present invention have a volume average particle diameter of 0.05 μm or more and 5 μm or less, preferably 0.1 μm or more and 2 μm or less, and have a sharp particle size distribution.

When the volume average particle size of the particles of the present invention is less than 0.05 μm, the mechanical strength required for the surface of the photosensitive layer cannot be obtained, and the particles are easily worn or damaged during the repeated image formation process, and the electrophotographic performance is deteriorated. to degrade. On the other hand, when the thickness exceeds 5 μm, the surface roughness of the photosensitive layer becomes large, and cleaning failure occurs.

Further, the particles are preferably substantially spherical, and particularly preferably substantially spherical with a major axis / minor axis ratio of less than 2.0. Here, the spherical shape means 10,000 in an electron microscope. It is shown that the doubled particles 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. Further, it is preferable that the particles have a sharp particle size distribution as described above, 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. The volume average particle diameter of the particles is measured by a laser diffraction / scattering type particle size distribution measuring device LA-700 (manufactured by Hakuba Seisakusho).

In the present invention, these particles are contained at least in the outermost surface layer of the electrophotographic photosensitive member together with the binder. The proportion of the particles in the outermost surface layer is usually 1% by weight or more and 200% by weight or less with respect to the binder, and desirably. Is 5% by weight or more 1
Used up to 00% by weight.

The photosensitive layer of the electrophotographic photosensitive member of the present invention in which the above particles are contained in the outermost surface layer may be an inorganic photosensitive member using selenium, amorphous silicon, cadmium sulfide or the like, but is preferably an organic photosensitive member. Is an organic photoconductor containing the charge generating substance (CGM) and the charge transporting substance (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 are protective layers 5 on the photosensitive layers 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.

Of 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 addition, the silica particles of the present invention are contained therein.

The protective layer, when provided, is composed of at least a resin and the particles of the present invention, 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 the following compounds.

[0035]

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[0036]

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[0037]

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[0038]

[Chemical 4]

[0039]

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[0040]

[Chemical 6]

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 when forming each of the layers, those mentioned as the solvent or dispersion medium of the polycarbonate resin are preferably used. 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 1:10 to 1 in weight ratio.
0: 1, especially 1: 5 to 5: 1 is preferred. The film thickness of the charge generation layer is preferably 5 μm or less, particularly 0.05 to 2 μm.
Is preferred.

The charge-transporting layer is formed by dissolving the above-mentioned charge-transporting substance and the binder resin in a suitable solvent and applying 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, 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.

The photosensitive layer of the present invention is prepared by coating and drying a predetermined layer as described above. The residual solvent amount after drying is 2% or less of the photosensitive layer, preferably 1.5%. It is the following. To obtain such a residual solvent amount, the drying temperature is
90 to 120 ° C, preferably 95 to 120 ° C. When such a residual solvent amount is used, the repeating characteristics are improved.

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) a support such as paper or a plastic film, and aluminum, palladium or gold on the support. 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. Regarding the spray coating, for example, JP-A-3-
90250 and Japanese Patent Laid-Open No. 3-269238,
Regarding the circular amount regulation type coating, for example, JP-A-58-18906
It is described in detail in the publication No. 1.

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 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 denotes a photosensitive drum, which is an image bearing member, and is coated with an OPC photosensitive layer, 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 carried out, 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.

Next, 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.
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 exposing means irradiates the photoconductor with reflected light or transmitted light from the original document, or a sensor reads the original document and converts 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.

[0070]

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 7 and Comparative Examples 1 to 4] Diameter 8
Copolymerized polyamide resin "Amilan CM-8000" (manufactured by Toray Industries, Inc.) on a 0 mm aluminum drum.
A coating solution prepared by dissolving 5 parts by weight in a mixed solvent of 90 parts by volume of methanol and 10 parts by volume of butanol was applied by dip coating to form an intermediate layer having a film thickness of 0.3 μm. Next, polyvinyl butyral resin "ESREC BL-S" (manufactured by Sekisui Chemical Co., Ltd.)
0.8 parts by weight was dissolved in a mixed solvent of 80 parts by weight of methyl ethyl ketone and 20 parts by weight of cyclohexanone, and 4 parts by weight of CGM-1 represented by the following structural formula (CGM / binder ratio) was added to the resulting solution. 5.0) and mixed and dispersed to form a charge generation layer having a thickness of 0.2 μm after the coating liquid was applied by dipping onto the intermediate layer.

[0072]

[Chemical 7]

Next, as a binder, a polycarbonate resin “UPILON Z300” (manufactured by Mitsubishi Gas Chemical Co., Inc.) 15
Parts by weight and the compound (T-
A coating solution prepared by dissolving 10 parts by weight of 17) in 100 parts by volume of methylene chloride was applied onto the charge generation layer by dip coating to form a first charge transport layer having a thickness of 25 μm after drying.

Further, as a binder, a polycarbonate resin "Iupilon Z800" (manufactured by Mitsubishi Gas Chemical Co., Inc.)
5 parts by weight and silica particles of High Presica (manufactured by Ube Nitto Kasei Co., Ltd., specific gravity: 1.6) and Admafine (Admatex Co., Ltd., specific gravity: 2.2) as shown in Table 1 were each added in a weight% of the binder. As a charge transport substance, 1 part by weight of the compound (T-17) shown in "Chemical Formula 4" is dissolved and dispersed in 100 parts by volume of 1,2-dichloroethane to form a coating solution on the first charge transport layer in a circular amount regulation. A second charge transport layer having a film thickness of 1 μm was formed by applying the solution using a die coater and drying the film at 110 ° C. for 1 hour to obtain a photoreceptor 1 for an example shown in Table 1.

<Production of Photoreceptors 2 to 7 for Examples and Photoreceptors 1 to 4 for Comparative Examples> Table 1 shows the types of silica particles, volume average particle diameter, and ratio (% by weight) to the binder of the photoreceptor 1. Example photoconductors 2 to 7 and comparative photoconductors 1 to 4 were obtained in the same manner as the photoconductor 1 except that the contents were changed to. The specific gravity of Seahosta (manufactured by Nippon Shokubai Co., Ltd.) was 1.8.

[0076]

[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 as a unit. 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 mounted on 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, and the sharpness of the image were visually observed, and the results are shown in Table 2. It was shown to.

2) Measurement of Potential Fluctuation Amounts of black paper potential (Vb) and white paper potential (Vw) before and after the 100,000 times image forming test are measured, and from the difference ΔVb and ΔVw, the photoconductors before and after image formation are measured. The amount of potential fluctuation was calculated and the result is shown in Table 2.

An original having half a solid black area with a reflection density of 1.3 and half a solid white area with a reflection density of 0.0 was used as the original for measurement, and it 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.

[0082]

[Table 2]

From Table 2, in the examples using the respective photoreceptors for the examples, the potential fluctuations such as the black paper potential and the white paper potential and the film thickness wear 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.

[Examples 8 to 13 and Comparative Examples 5 to 7] The same procedure as in Example 1 was repeated except that the charge transporting material in Example 1 was changed to T-2 in Chemical formula 1. However, the silica particles added to the second charge transport layer of the outermost surface layer were excluded, and instead, as shown in Table 3, composite oxide particles of two different metals or particles for comparison were added.

[0085]

[Table 3]

These photoconductors were evaluated by the same method and standard as in Example 1 and thereafter. The results are shown in Table 4.

[0087]

[Table 4]

From Table 4, in the case of using each of the photoconductors for the examples, there is little potential fluctuation such as black paper potential and white paper potential and film thickness wear in the process of repeated image formation, and clear image without background fog or streak failure. However, in each comparative example using the photoconductor for the comparative example, a background fog or a streak failure occurs in the process of repeatedly forming an image, and the thickness loss is large, so that a good image cannot be obtained. I understand.

[0089]

According to the present invention, it is possible to provide a photosensitive member that improves the durability of the organic photosensitive member and does not deteriorate the characteristics of the cleaning blade that is pressed against the surface of the photosensitive layer. As a result, it is possible to provide an electrophotographic apparatus and apparatus unit that can stably obtain a high-density and high-definition image from beginning to end.

[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]

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 Photosensitive drum 11 Exposure section using light emitting diode 12 Scorotron charger 13 Image exposure means 14 Developing device 17 Paper feeding roller 18 Transfer roller 19 Separation brush 20 Fixing device 21 Paper discharging roller 22 Cleaning device 30 Removable cartridge in which image holding member, charging means, developing means and cleaning means are integrated

Claims (5)

[Claims] 1. A photosensitive layer of an electrophotographic photosensitive member, wherein the outermost surface layer contains any of the following particles. (1) Two or more kinds of silica particles having different specific gravities (2) Composite oxide particles of two or more kinds of metals different from each other 2. The electrophotographic photosensitive member according to claim 1, wherein the composite oxide particles of two or more metals are composite oxide particles of silicon atoms and metal atoms other than silicon atoms. 3. The electrophotographic photosensitive member according to claim 1, wherein the particles contained in the outermost surface layer have a volume average particle size of 0.05 μm or more and 5.0 μm or less. 4. The outermost surface layer of the photosensitive layer has an electrophotographic photosensitive member containing any of the following particles, an electrostatic latent image forming means, a developing means, a transferring means, and an elastic blade cleaning means. Electrophotographic device. (1) Two or more kinds of silica particles having different specific gravities (2) Composite oxide particles of two or more kinds of metals different from each other 5. An electron of an electrophotographic apparatus having an electrophotographic photosensitive member in which the outermost surface layer of the photosensitive layer contains any of the following particles, an electrostatic latent image forming means, a developing means, a transferring means, and an elastic blade cleaning means. An electrophotographic apparatus unit comprising a photographic photosensitive member and at least one of the above means. (1) Two or more kinds of silica particles having different specific gravities (2) Composite oxide particles of two or more kinds of metals different from each other