JP2002116566A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electrophotographic photoreceptor more excellent in durability than a conventional one because it has an inorganic surface protecting layer less liable to cause cracking and peeling in a practical service environment and due to long-term storage and excellent in physical stability. SOLUTION: The electrophotographic photoreceptor is obtained by stacking an organic photosensitive layer and an inorganic surface protecting layer in this order and at least the top part of the organic photosensitive layer brought into contact with the surface protecting layer contains a diindenopyrazine derivative of formula (1) [where R1-R3 are the same or different and each H, halogen, alkyl, alkoxy, aryl or aralkyl; (n) and (m) are the same or different and each an integer of 0-4; and (o) is an integer of 0-5] or formula (2) [where R4 and R5 are the same or different and each H, halogen, alkyl, alkoxy, aryl or aralkyl and (p) and (q) are the same or different and each an integer of 0-4].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member.

[0002]

2. Description of the Related Art As an electrophotographic photoreceptor used in an image forming apparatus such as an electrostatic copying machine, a laser printer, a plain paper facsimile machine, etc., a so-called organic photoreceptor formed by combining the following components is widely used. are doing. A charge generating agent that generates charges (holes and electrons) by light irradiation;・ Charge transport agent that transports generated charges (Charge transport agent is
A hole transporting agent that transports holes among charges and an electron transporting agent that transports electrons). -A binder resin having film forming properties.

An organic photoreceptor has an advantage that it can be easily manufactured at a low cost as compared with an inorganic photoreceptor using an inorganic semiconductor material.

Further, the organic photoreceptor has an advantage that the material selection such as the above-mentioned charge generating agent, charge transporting agent, and binder resin is diversified, and the degree of freedom in functional design is large.

The above-mentioned organic photoreceptor is constituted by forming a single-layer type or a laminated type photosensitive layer on a conductive substrate.

Among them, the single-layer type photosensitive layer contains a charge generating agent,
It is formed by dispersing in a binder resin together with a charge transport agent (a hole transport agent and / or an electron transport agent).

[0007] The laminated type photosensitive layer is formed by laminating a charge generating layer containing a charge generating agent and a charge transporting layer containing a charge transporting agent (a hole transporting agent or an electron transporting agent).

[0008]

Although the organic photoreceptor has various advantages as described above, the photoreceptor layer is liable to be scraped or scratched in an actual use environment, and has a higher durability than an inorganic photoreceptor. There is a problem that the nature is not enough.

In order to solve this problem and improve the durability of the organic photoreceptor, it has been studied to laminate a surface protective layer on the outermost layer.

[0010] Examples of the surface protective layer, which is widely and generally employed, include, for example, a layer formed in consideration of the adhesion to the organic photosensitive layer, the affinity, the integrity in the laminated state, the consistency of the film forming operation, and the like. An organic layer such as a layer of a binder resin having a film property, or a layer in which conductive fine particles such as a metal oxide are dispersed in the binder resin, may be used.

However, an electrophotographic photoreceptor using this organic layer as a surface protective layer has large fluctuations in sensitivity characteristics due to changes in environment (temperature, humidity, etc.) due to a rise in residual potential and a decrease in chargeability upon repeated use. There is a problem.

Therefore, recently, an inorganic layer made of an inorganic material, such as a metal element or carbon, or an inorganic compound containing these elements, having high hardness and excellent abrasion resistance is used as a surface protective layer. For example, sputtering method, plasma CVD
It has been studied to stack and form a film on the organic photosensitive layer by a vapor deposition method such as a photo-assisted CVD method.

The surface protective layer protects the organic photosensitive layer,
This is used to solve the above problem.
In other words, the photoreceptor provided with an inorganic surface protective layer on the organic photosensitive layer, the organic photosensitive layer is responsible for the generation and transport of charge, and the surface protective layer is responsible for the durability and environmental resistance of the photoreceptor, respectively. Has a function corresponding to the characteristics of the layer.

However, it is difficult to obtain sufficient adhesion between the inorganic surface protective layer and the organic photosensitive layer as compared with the organic layer. However, even if the adhesion of the photosensitive member can be ensured, there is a problem that cracks are easily formed or peeled off due to various stresses applied to the photoreceptor in an actual use environment or during long-term storage.

That is, the organic photosensitive layer and the inorganic surface protective layer, which are made of materials different from each other, do not have close adhesion, affinity, and unity like organic layers or inorganic layers. Often, they are only joined together with very weak binding forces.

Therefore, the photoreceptor is subjected to mechanical stress due to, for example, pressure contact of a cleaning blade of the image forming apparatus, or thermal stress due to repeated heating and cooling during operation of the apparatus, or temperature change during storage and the like. Due to the fact that the hardness, flexibility, expansion / shrinkage characteristics, etc. of each other are greatly different, the inorganic surface protective layer is cracked or the surface protective layer is peeled off from the organic photosensitive layer as described above. Or do it.

Therefore, the conventional inorganic surface protective layer has not yet been sufficiently effective in improving the durability of the organic photosensitive layer.
At present, it has not been put to practical use.

An object of the present invention is to provide an inorganic surface protective layer which is hardly cracked or peeled off in an actual use environment or for a long period of storage and has excellent physical stability, and has a more durable state than before. It is to provide an excellent organic electrophotographic photoreceptor.

[0019]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, the present inventors have analyzed and studied the process of forming an inorganic surface protective layer.

As a result, it has been found that the initial state of the formation of the surface protective layer on the outermost surface of the organic photosensitive layer greatly affects the subsequent physical stability of the surface protective layer.

That is, at the initial stage of film formation, the inorganic material constituting the surface protective layer and a part of the material exposed on the outermost surface of the organic photosensitive layer are combined in some way to form a nucleus for film growth. A film of an inorganic material grows around the nucleus to form a surface protective layer, and in the formed surface protective layer, the nucleus portion functions as a bonding point with the organic photosensitive layer to form a layer between the two layers. Works to ensure adhesion.

Therefore, the strength of the bonding between the organic photosensitive layer and the inorganic material at each bonding point and the number of bonding points per unit area, ie, the density, at the interface between the organic photosensitive layer and the surface protective layer Of the surface protective layer greatly affects the adhesion of the surface protective layer to the organic photosensitive layer, and furthermore, the physical stability of the surface protective layer.

More specifically, the stronger the bonding strength between the organic photosensitive layer and the inorganic material at each bonding point, and the higher the density of the bonding points at the interface between both layers, the more the organic protective layer of the surface protective layer The adhesion to the layer is improved and its physical stability is improved.

The ordinary organic photosensitive layer has a structure in which a low-molecular functional material such as a charge generating agent and a charge transporting agent is dispersed in a binder resin constituting the layer, as described above.

For this reason, in view of the above knowledge about the bonding point, the binder resin constituting the layer itself and occupying most of the layer binds to the inorganic material constituting the surface protective layer as a core for film growth. Is considered ideal.

However, in practice, of the low molecular weight materials dispersed in the layer, such as a charge generating agent and a charge transporting agent, of the organic photosensitive layer, due to the stability and reactivity of the molecule itself or the relationship of the reaction site. The part exposed at the outermost surface functions as a nucleus for film growth, and the formation of the surface protective layer often proceeds.

Therefore, the reactivity of the low molecular material with the inorganic material, the magnitude of the binding force, the compatibility with the binder resin constituting the organic photosensitive layer, the strength of the affinity, or the material itself The size (including molecular and spatial extent as well as molecular weight) of the surface protective layer
It greatly affects the adhesion to the organic photosensitive layer and the physical stability.

That is, the lower the molecular weight of the material, the better the reactivity with the inorganic material and the larger the bonding force, the more the surface protective layer
Adhesion with the organic photosensitive layer and physical stability are improved.

The lower the molecular weight of the material, the better the compatibility and affinity with the binder resin constituting the organic photosensitive layer, and the larger the size of the material itself, the more the so-called anchor effect (anchoring effect) results. The adhesion of the protective layer to the organic photosensitive layer and the physical stability are improved.

The bonding form between the low-molecular material and the inorganic material is most preferably a molecular bond in consideration of the strength of the bonding force. However, as a result of the change in the molecular structure due to this bond, charge traps are generated. When something like that happens,
There is a possibility that the sensitivity of the photoconductor is reduced.

Therefore, it is also important that a low-molecular material does not shift to a molecular state in which electrical properties are lowered by a reaction.

As described above, it has been found that a photoreceptor capable of forming a good image cannot be easily produced simply by laminating a material having high hardness on a conventional photosensitive layer. Further, the photoreceptor manufactured under the above-described conditions can improve the durability and environmental resistance of the surface protective layer while maintaining the electrical characteristics of the organic photosensitive layer.

The present inventors have studied various materials constituting the organic photosensitive layer in consideration of these findings, and as a result, the following formula (1) used as a hole transport agent:

[0034]

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Wherein R ^{1 to} R ³ are the same or different and each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, and n and m are the same or different and are each an integer of 0 to 4 , P represents an integer of 0 to 5. Or equation (2):

[0036]

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Wherein R ^{4 to} R ⁵ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, and q and r are the same or different and are each an integer of 0 to 4 Is shown. The diindenopyrazine derivative represented by the formula (1) was found to be a suitable material satisfying these requirements, and the present invention was completed.

That is, the electrophotographic photoreceptor of the present invention comprises an organic photosensitive layer and an inorganic surface protective layer laminated in this order on a conductive substrate. Is characterized in that the outermost surface part in contact with the diindenopyrazine derivative represented by the above formula (1) or (2).

The diindenopyrazine derivative represented by the above formula (1) or (2) has a π-electron conjugated system spread throughout the molecule, and forms a surface protective layer at an early stage of film formation. It has a function of attracting a metal element, carbon, and the like among inorganic materials, and has high reactivity with inorganic materials.

Further, by the above function, the diindenopyrazine derivative exposed on the outermost surface of the organic photosensitive layer has a high rate of bonding with the inorganic material and serving as a nucleus for film growth. High density.

Further, since the speed of film growth is high, damage to the organic photosensitive layer when the surface protective layer is formed by a vapor phase growth method or the like can be reduced as much as possible.

In addition, the diindenopyrazine derivative has a double bond in the molecule in which the π bond is broken, and the diindenopyrazine derivative is firmly bonded to the above-mentioned metal element or carbon by a molecular bond. In particular, since the π bond of the carbonyl group greatly differs in the electronegativity between carbon and oxygen, the reactivity contributing to the bipolar resonance structure in which carbon becomes positive and oxygen becomes negative increases, and the organic photosensitive layer and inorganic material And the bonding strength with the substrate becomes very strong.

Furthermore, the diindenopyrazine derivative has a molecular structure that spreads in a plane, has a large molecular and spatial spread, and has excellent compatibility and affinity with the binder resin. Therefore, it exhibits a good anchoring effect on the binder resin.

Therefore, the bonding strength between the organic photosensitive layer and the inorganic material is large.

Therefore, according to the present invention, the adhesion of the inorganic surface protective layer to the organic photosensitive layer can be improved, and the physical stability of the surface protective layer can be improved. It is possible to prevent the occurrence of cracks and peeling due to the above-mentioned factors, and to obtain an electrophotographic photosensitive member having more excellent durability than before.

The diindenopyrazine derivative itself has a high electron transporting ability, and generates a deep charge trap even when the molecular structure is changed by the molecular bonding with a metal element or carbon as described above. And the above-mentioned bond occurs only in a very small portion of the diindenopyrazine derivative exposed on the outermost surface of the organic photosensitive layer. In addition, since the state in which the electron transporting ability is excellent is maintained, there is no possibility that the sensitivity of the photoconductor is reduced.

Therefore, the diindenopyrazine derivative is excellent in compatibility with the binder resin as described above, and can be uniformly and abundantly dispersed in the organic photosensitive layer without causing aggregation or the like. Accordingly, the electrophotographic photoreceptor of the present invention also has excellent sensitivity characteristics.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. <Diindenopyrazine derivative> In the electrophotographic photoreceptor of the present invention, the organic photosensitive layer, at least the diindenopyrazine derivative contained in the outermost surface portion in contact with the surface protective layer,
Equation (1) as described above:

[0049]

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Wherein R ^{1 to} R ³ are the same or different and each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, and n and m are the same or different and are each an integer of 0 to 4 , P represents an integer of 0 to 5. Or equation (2):

[0051]

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Wherein R ^{4 to} R ⁵ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, and q and r are the same or different and are each an integer of 0 to 4 Is shown. ].

Examples of the alkyl group corresponding to the groups R ^{1 to} R ⁵ in the formula include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and t-butyl.
tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and the like,
Examples thereof include an alkyl group having 1 to 12 carbon atoms.

The alkoxy groups corresponding to the groups R ^{1 to} R ⁵ include, for example, methoxy, ethoxy, n-propoxy,
Isopropoxy, n-butoxy, isobutoxy, sec
-Alkoxy groups having 1 to 12 carbon atoms such as -butoxy, tert-butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy and the like.

Examples of the aryl group include those having 6 carbon atoms such as phenyl, tolyl, xylyl, biphenylyl, o-terphenyl, naphthyl, anthryl and phenanthryl.
To 14 aryl groups.

As the aralkyl group, for example, benzyl,
An aralkyl group having 6 to 14 carbon atoms such as benzhydryl, trityl and phenethyl is exemplified.

The alkyl group, alkoxy group, aryl group, and aralkyl group corresponding to the groups R ^{1 to} R ⁵ may have a substituent, and specific examples thereof include a hydroxyalkyl group, an alkoxyalkyl group, and a monoalkylaminoalkyl. Group, dialkylaminoalkyl group, halogen-substituted alkyl group, alkoxycarbonylalkyl group, carboxyalkyl group,
Having an alkanoyloxyalkyl group, an aminoalkyl group, a halogen atom, an amino group, a hydroxy group, a carboxyl group which may be esterified, a cyano group, etc. And an alkoxy group which may have a substituent having 1 to 12 carbon atoms. In addition, the substitution positions of these substituents are not particularly limited.

Specific examples of such diindenopyrazine derivatives include, but are not limited to, diindenopyrazine derivatives of the formula (1), for example,
To (1-4).

[0059]

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[0060]

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The diindenopyrazine derivative of the formula (2) includes, for example, compounds represented by the following formulas (2-1) to (2-4).

[0062]

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[0063]

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The above diindenopyrazine derivatives may be used alone or in combination of two or more. <Organic photosensitive layer> As described above, the organic photosensitive layer includes a single-layer photosensitive layer and a laminated photosensitive layer, and any of them can be applied to the present invention.

Among them, the single-layer type photosensitive layer comprises a hole transporting agent,
It is generally formed by applying a charge generating agent and a coating liquid dissolved or dispersed in a suitable organic solvent together with a binder resin onto a conductive substrate by means such as coating and drying. is there. In the present invention, the diindenopyrazine derivative represented by the formula (1) or (2) as an electron transporting agent is further dissolved or dispersed in the coating liquid to form a single-layer photosensitive layer. I do.

The single-layer type photosensitive layer described above has a simple layer structure and is excellent in productivity, and uses a bipolar charge transport agent in combination. There is an advantage that it can also respond to.

On the other hand, in the laminated photosensitive layer, first, a charge generating layer containing a charge generating agent is formed on a conductive substrate by means of coating or vapor deposition, and then a charge transporting agent is formed on the charge generating layer. And a coating liquid containing a binder resin, is applied by means such as coating, and dried to form a charge transport layer, or, conversely, to form a charge transport layer on a conductive substrate, It is constituted by forming a charge generation layer thereon.

The charge generating layer may contain a charge transporting agent having a polarity opposite to that of the charge transporting layer.

Various combinations of the layered photosensitive layer can be considered depending on the formation order of the charge generation layer and the charge transport layer, and the polarity of the charge transport agent contained in both layers. Formula (1) wherein the upper layer located on the outermost surface in contact with the protective layer functions as a hole transporting agent.
Alternatively, it needs to contain a diindenopyrazine derivative of the formula (2).

Accordingly, specific examples of the laminated photosensitive layer include (a) a charge generating layer containing a charge generating agent and, if necessary, an electron transporting agent formed on a conductive substrate; Negatively-chargeable laminate in which a charge transport layer containing a hole transport agent (and further containing a diindenopyrazine derivative of the formula (1) or (2) as an electron transport agent in the present invention) is further laminated. Forming a charge transporting layer containing an electron transporting agent on a conductive layer and a photosensitive substrate, and (b) containing a charge generating agent and, if necessary, a hole transporting agent (the present invention) And (c) a conductive layer comprising a negative charge type laminated photosensitive layer further comprising a charge generation layer further containing a diindenopyrazine derivative represented by the above formula (1) or (2) as an electron transporting agent. On top, contains a charge generating agent and, if necessary, a hole transporting agent A positively-charged laminated photosensitive layer in which a charge generating layer is formed, and a charge transporting layer containing a diindenopyrazine derivative of the formula (1) or (2) as an electron transporting agent is laminated thereon; (D) On a conductive substrate,
Form a hole transport layer containing a hole transport agent, on which,
A charge generating layer containing a charge generating agent and, if necessary, a hole transporting agent is formed, and a diindine represented by the above formula (1) or (2) as an electron transporting agent is further formed thereon. A positively-charged laminated photosensitive layer in which an electron transporting layer containing a nopyrazine derivative is laminated;

Of these, the negatively charged type photosensitive layer is preferably of the negatively charged type because the laminated photosensitive layer has better electrical characteristics such as photosensitivity and residual potential than the positively charged type photosensitive layer.

The charge generation layer is very thin compared to the charge transport layer. To protect the charge generation layer, a charge generation layer is formed on a conductive substrate, and a charge transport layer is formed thereon. The above configuration (a) is more preferable.

Examples of the charge generating agent used in the single-layer or multilayer photosensitive layer include powders of inorganic photoconductive materials such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and α-silicon; CG-1):

[0074]

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A metal-free phthalocyanine represented by the formula (C)
G-2):

[0076]

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Of phthalocyanine compounds such as titanyl phthalocyanine represented by the formula: phthalocyanine pigments composed of crystals having various crystal types, azo pigments, bisazo pigments, perylene pigments, anthanthrone pigments, indigo pigments, Various conventionally known pigments such as a phenylmethane pigment, a threne pigment, a toluidine pigment, a pyrazoline pigment, a quinacridone pigment, and a dithioketopyrrolopyrrole pigment are exemplified.

The charge generators can be used alone or in combination of two or more so that the photosensitive layer has sensitivity in a desired wavelength range.

In particular, an image forming apparatus of a digital optical system such as a laser beam printer or a plain paper facsimile apparatus utilizing infrared light such as a semiconductor laser needs a photosensitive member having a sensitivity in a wavelength region of 700 nm or more. For,
As the charge generator, a phthalocyanine-based pigment among the above examples is preferably used.

In the present invention, another electron transporting agent may be used in combination with the diindenopyrazine derivative of the formula (1) or (2) which is an electron transporting agent.

As the other electron transporting agent, any of various conventionally known electron transporting compounds can be used.

In particular, benzoquinone compounds, naphthoquinone compounds, malononitriles, thiopyran compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, fluorenone compounds [for example, 2,4,7-trinitro-9-fluorenone and the like] , Dinitrobenzene,
Dinitroanthracene, dinitroacridine, nitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, 2,4,7-trinitrofluorenoneimine compound, ethylated nitrofluorenoneimine compound, tryptoantrine compound, tripto Toantrinimine compounds, azafluorenone compounds, dinitropyridoquinazoline compounds, thioxanthene compounds, diphenoquinone compounds, 2-phenyl-1,4
-Benzoquinone-based compounds, 5,12-naphthacenequinone-based compounds, α-cyanostilbene-based compounds, 4'-nitrostilbene-based compounds, and electron-withdrawing compounds such as salts of benzoquinone-based compounds with anion radicals and cations are preferred. Used for

These are used alone or in addition to
More than one species may be used in combination.

As the hole transporting agent, any of various conventionally known hole transporting compounds can be used.

In particular, stilbene compounds, benzidine compounds, phenylenediamine compounds, naphthylenediamine compounds, phenanthrylenediamine compounds, oxadiazole compounds [for example, 2,5-di (4-methylaminophenyl)- 1,3,4-oxadiazole, etc.), styryl-based compounds [eg, 9- (4-diethylaminostyryl) anthracene, etc.], carbazole-based compounds [eg, formula (HT-1):

[0086]

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Poly-N having a repeating unit represented by
-Vinyl carbazole etc.], Formula (HT-2):

[0088]

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[Wherein R ^a and R ^b are the same or different,
It represents an alkyl group, an alkoxy group, an aryl group, or an aralkyl group. An organic polysilane compound having a repeating unit represented by the formula (I), a pyrazoline-based compound (eg, 1-phenyl-3- (p-dimethylaminophenyl) pyrazolin, etc.), a hydrazone-based compound (eg, a compound represented by the formula (HT-
3):

[0090]

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Such as diethylaminobenzaldehyde diphenylhydrazone, etc.), triphenylamine compounds, indole compounds, oxazole compounds,
Isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, butadiene compounds, pyrene-hydrazone compounds, acrolein compounds, carbazole-hydrazone compounds, quinoline-hydrazone compounds , A stilbene-hydrazone compound,
And diphenylenediamine compounds are preferably used.

These can be used alone or in addition to
More than one species may be used in combination.

Examples of the binder resin include a styrene polymer, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-maleic acid copolymer,
Acrylic polymer, styrene-acrylic copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane , Polycarbonate,
Thermoplastic resins such as polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, and silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, and other cross-linkable thermosetting resins, Photo-curable resins such as epoxy-acrylate and urethane-acrylate are exemplified.

These can be used alone, respectively.
Two or more can be used in combination.

Further, among the hole transporting agents exemplified above, poly-
When a high molecular weight hole transporting agent such as N-vinyl carbazole or an organic polysilane compound is used, the compound may also function as a binder resin, and the above-described ordinary binder resin may be omitted.

In addition to the above components, various additives such as a fluorene compound, an ultraviolet absorber, a plasticizer, a surfactant and a leveling agent may be added to the photosensitive layer. In order to improve the sensitivity of the photoreceptor, a sensitizer such as terphenyl, halonaphthoquinones, and acenaphthylene may be added.

In the single-layer type photosensitive layer, the binder resin 100
0.1 to 50 parts by weight, particularly 0.5 to 30 parts by weight, of the charge generating agent and 5 to 5 parts by weight of the hole transporting agent.
It is preferable to contain each in an amount of 500 parts by weight, particularly 25 to 200 parts by weight. The electron transporting agent is used in an amount of 5 to 100 parts by weight, especially 1 to 100 parts by weight of the binder resin.
It is preferable to contain it at a ratio of 0 to 80 parts by weight.

When the diindenopyrazine derivative of the formula (1) or (2) is used alone, the content of the electron transporting agent is the content of the diindenopyrazine derivative. When a pyrazine derivative and another electron transporting agent are used in combination, the content ratio is the total content of both.

When a diindenopyrazine derivative is used in combination with another electron transporting agent, the other electron transporting agent is preferably contained in a small amount as long as the effect of the diindenopyrazine derivative is not impaired. . Specifically, it is preferable to mix another electron transporting agent in an amount of 30 parts by weight or less based on 100 parts by weight of the diindenopyrazine derivative.

At this time, the total amount of the hole transporting agent and the electron transporting agent is preferably 20 to 500 parts by weight, particularly preferably 30 to 200 parts by weight, based on 100 parts by weight of the binder resin.

The thickness of the single-layer type photosensitive layer is preferably 5 to 100 μm, particularly preferably about 10 to 50 μm.

As described above, the charge-generating layer of the laminated photosensitive layer is formed of the charge-generating agent alone, or the charge-generating agent is contained in the binder resin, if necessary, as described above. (Electron transporting agent or hole transporting agent) in some cases. In the latter configuration, the charge generating agent is added in an amount of 5 to 1000 parts per 100 parts by weight of the binder resin.
Parts by weight, particularly 30 to 500 parts by weight, and when the electron transporting agent is contained, the electron transporting agent is 1 to 200 parts by weight.
It is preferable that each of them is contained in an amount of 5 parts by weight, particularly 5 to 100 parts by weight. 1 when the hole transport agent is contained
It is preferred that the content be contained at a ratio of from 200 to 200 parts by weight, especially from 5 to 100 parts by weight.

In the charge transport layer, the binder resin 10
When the electron transporting agent is contained with respect to 0 parts by weight, the electron transporting agent is 0.1 to 250 parts by weight, particularly 0.5 to 1 part by weight.
When the hole transport agent is contained at a ratio of 50 parts by weight,
10 to 500 parts by weight, particularly 25 to 20 parts by weight of the hole transporting agent.
It is preferable to contain each of them in a proportion of 0 parts by weight.

When the diindenopyrazine derivative of the formula (1) or (2) is used alone, the content of the electron transporting agent is determined in the same manner as in the case of the single-layer type photosensitive layer. This is the content ratio of the nopyrazine derivative. When the diindenopyrazine derivative is used in combination with another hole transporting agent, it is the total content ratio of both.

When a diindenopyrazine derivative is used in combination with another electron transporting agent, the other electron transporting agent is preferably contained in a small amount as long as the effect of the diindenopyrazine derivative is not hindered. . Specifically, it is preferable to mix another hole transporting agent in an amount of 30 parts by weight or less based on 100 parts by weight of the diindenopyrazine derivative.

The thickness of the laminate type photosensitive layer is set at 0.
The thickness is preferably from 01 to 5 µm, particularly about 0.1 to 3 µm, and the charge transport layer is preferably from 2 to 100 µm, especially about 5 to 50 µm.

The properties of the photoreceptor are between the single-layer or laminated organic photosensitive layer and the conductive substrate, or between the charge generating layer and the charge transport layer constituting the laminated photosensitive layer. An intermediate layer and a barrier layer may be formed as long as they do not interfere.

When each layer constituting the photoreceptor is formed by a coating method, the charge generating agent, the charge transporting agent, the binder resin and the like described above may be used together with the above-mentioned organic solvent such as tetrahydrofuran in a known method. For example, a coating solution may be prepared by dispersing and mixing using a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser, or the like, and the coating solution may be applied and dried by known means.

Examples of the organic solvent for preparing the coating liquid include alcohols such as methanol, ethanol, isopropanol and butanol, n-hexane, octane, and the like.
Aliphatic hydrocarbons such as cyclohexane, benzene, toluene, aromatic hydrocarbons such as xylene, dichloromethane, dichloroethane, carbon tetrachloride, halogenated hydrocarbons such as chlorobenzene, dimethyl ether, diethyl ether, tetrahydrofuran, 1,4-dioxane, Ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone and cyclohexanone;
Ester such as ethyl acetate and methyl acetate, and one or more of dimethylformaldehyde, dimethylformamide, dimethylsulfoxide and the like.

Further, in order to improve the dispersibility of the charge transporting agent and the charge generating agent and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent and the like may be added to the coating solution. <Surface protective layer> As an inorganic surface protective layer laminated and formed on the organic photosensitive layer, a metal element [on the left side of a line connecting boron (B) and astatine (At) in the long period type periodic table] is used. A certain element], at least one element selected from the group consisting of carbon, or an inorganic compound containing these elements.

This surface protective layer is formed, for example, by plasma CVD.
It can be formed by conventionally known various vapor phase growth methods such as a chemical vapor deposition method such as a photo-CVD method, a physical vapor deposition method such as a sputtering method, a vacuum vapor deposition method, and an ion plating method.

Among them, in the chemical vapor deposition method such as the plasma CVD method, (1) a film made of carbon (C) and / or silicon (Si) among the Group 14 elements, that is, a film of carbon (C) and silicon (Si) Film or silicon-carbon (Si
C) a composite film, (2) the carbon (C) and / or silicon (Si), boron (B) and aluminum (Al) among the group 13 elements, nitrogen (N) and phosphorus (P ), Oxygen (O), sulfur (S),
A film made of a compound with at least one element selected from the group consisting of fluorine (F), chlorine (Cl), and bromine (Br) among group 17 elements, for example, silicon-nitrogen (Si
N) composite film, silicon-oxygen (SiO) composite film, carbon-fluorine (CF) composite film, carbon-nitrogen (CN) composite film, carbon-boron (CB) composite film, carbon-oxygen (CO) composite film, etc. , (3) boron (B) and / or aluminum (Al) among the group 13 elements and nitrogen (N), phosphorus (P), oxygen (O), sulfur (S), fluorine (F), chlorine (Cl) and a film made of a compound with at least one element selected from the group consisting of bromine (Br), for example, a boron-nitrogen (BN) composite film, an aluminum-nitrogen (A
1N) a composite film or the like is formed.

These films may contain a small amount of hydrogen (H) in order to improve the electrical characteristics of the surface protective layer.

In the chemical vapor deposition method, the source gas that can be used to introduce the constituent elements of the surface protective layer includes, for example, molecules of each constituent element, oxides, hydrides, nitrides, and halides at room temperature and normal pressure. Compounds that are gaseous or can be easily gasified under film-forming conditions are mentioned. If necessary, these compounds may be diluted with a gas such as hydrogen gas (H ₂ ), helium gas, argon gas, or neon gas.

Specific examples of the raw material gas include, for example, silane gas (SiH ₄ ) and disilane gas (S
i ₂ H _6), methane as a carbon introducing (CH _4), ethane (C ₂ H _6), propane gas (C ₃ H _8), ethylene gas (C ₂ H _4), fluorine gas (F for the introduction of fluorine
₂ ), bromine monofluoride gas (BrF), chlorine difluoride gas (ClF ₂ ), carbon tetrafluoride gas (CF ₄ ), silicon tetrafluoride gas (SiF ₄ ), and nitrogen gas (N ₂ ), ammonia gas (NH ₃ ), nitrogen oxide gas (NO _x ), borohydride gas for introducing boron [diborane gas (B ₂ H ₆ ), tetraborane gas (B ₄ H ₁₀ )]
Etc.].

The same applies to other constituent elements, and examples thereof include compounds which exhibit a gaseous state at normal temperature and normal pressure or which can be easily gasified under film forming conditions.

In the physical vapor deposition method, in particular, the sputtering method or the ion plating method, in addition to the above films, for example, gallium (Ga), indium (I
n) and the like, germanium (Ge), tin (Sn), lead (Pb) for group 14; arsenic (As) for group 15;
Selenium (Se) for group 16 such as antimony (Sb)
A film composed of one or more of various metal elements including the above or a film composed of an inorganic compound containing the above metal element can be formed.

Among these, a film suitable as an inorganic surface protective layer is, for example, a carbon (C) film or a silicon-carbon (Si) film.
C) a composite membrane and the like.

The thickness of the inorganic surface protective layer is from 0.01 to 30.
μm, particularly preferably about 0.1 to 10 μm.

The inorganic film forming the surface protective layer is amorphous,
The film may be in any form of microcrystal or crystal, and may be a film in which amorphous and crystal are mixed. <Conductive Substrate> Various conductive materials can be used as the conductive substrate on which the above layers are formed. For example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium,
Conductive substrates made of metals such as nickel, palladium, indium, stainless steel, brass, etc., substrates made of plastic materials on which the above metals are deposited or laminated, or coated with aluminum iodide, tin oxide, indium oxide, etc. And the like.

In short, it is only necessary that the substrate itself has conductivity or the surface of the substrate has conductivity. Also,
The conductive substrate preferably has a sufficient mechanical strength when used.

The shape of the conductive substrate may be any of a sheet shape, a drum shape and the like according to the structure of the image forming apparatus to be used.

[0123]

The present invention will be described below based on examples and comparative examples. Example 1 <Formation of Single-Layer Photosensitive Layer> 5 parts by weight of an X-type metal-free phthalocyanine crystal represented by the formula (CG-1) as a charge generating agent, a hole transporting agent, and a binder resin Having a repeating unit represented by the formula (HT-1) (number average molecular weight Mn = 9500) 100
Parts by weight, a mixture of 40 parts by weight of the diindenopyrazine derivative represented by the formula (1-1) as an electron transporting agent, and 800 parts by weight of tetrahydrofuran, mixed and dispersed for 50 hours using a ball mill to form a single layer. A coating solution for a photosensitive layer was prepared.

Next, this coating solution was applied on an aluminum tube as a conductive base material by a dip coating method, and dried with hot air at 100 ° C. for 30 minutes to form a film having a thickness of 25 μm.
m was formed. <Formation of Surface Protective Layer> After the aluminum tube on which the single-layer type photosensitive layer was formed as described above was set in a chamber of a plasma CVD apparatus, the vacuum was evacuated to an ultimate degree of vacuum of 0.67 Pa. The temperature of the raw tube was adjusted to 50 ° C. using a heater.

Next, methane gas (C
H ₄ ), silane gas (SiH ₄ ) and hydrogen gas (H ₂ )
Are supplied at the following flow rates, and the degree of vacuum is 0.47 h.
It was adjusted to Pa.

Methane gas: 208 SCCM Silane gas: 2.5 SCCM Hydrogen gas: 300 SCCM Next, in this state, a frequency of 13.56 MH was introduced into the chamber.
A high-frequency electric field having an output of 133 W is applied to generate a glow discharge, and amorphous silicon-carbon is formed on the surface of the single-layer photosensitive layer at a film forming rate of 0.2 μm / hr by a plasma CVD method. A 0.5 μm-thick surface protective layer made of a (SiC) composite film was formed to produce an electrophotographic photoreceptor of Example 1. [Examples 2 to 6] The electrophotographs of Examples 2 to 4 were carried out in the same manner as in Example 1 except that 40 parts by weight of the diindenopyrazine derivative having the formula number shown in Table 1 was used as the electron transporting agent. A photoreceptor was manufactured. Comparative Example 1 An electrophotographic photoreceptor of Comparative Example 1 was produced in the same manner as in Example 1 except that a diindenopyrazine derivative was not used as an electron transporting agent. [Examples 5 to 8, Comparative Example 2] Instead of polyvinyl carbazole having a repeating unit represented by the formula (HT-1) and serving as a hole transporting agent and a binder resin, Examples 1-4 and Comparative Examples except that 80 parts by weight of diethylaminobenzaldehyde diphenylhydrazone represented by the formula (HT-3) and 100 parts by weight of a Z-type polycarbonate (weight average molecular weight 20,000) as a binder resin were used. Example 5 in the same manner as in Example 1.
8. An electrophotographic photoreceptor of Comparative Example 2 was produced. <Sensitivity Characteristics Test (1)> With respect to the electrophotographic photoreceptors of the above Examples and Comparative Examples, a voltage applied to the surface of each photoreceptor was applied using a drum sensitivity tester manufactured by GENTEC, and a grid voltage was applied. Adjust the surface to + 800 ±
After charging to 20 V, the surface potential V ₀ (V) was measured.

Next, a white light of a halogen lamp, which is an exposure light source of the tester, was used to obtain a wavelength of 7 using a band-pass filter.
Light intensity 10 μW monochromatized to 80 nm and half-width 20 nm
When the surface of the electrophotographic photoreceptor is irradiated with monochromatic light of 1 cm / cm ² for 1 second, the time required for the surface potential V ₀ (V) to become １ ／ is measured, and half-exposure is performed. Quantity E _1/2 (μ
J / cm ² ). Further, the surface potential at the time when 0.5 seconds had elapsed from the start of exposure was measured as a residual potential Vr (V). <Repeated test (1)> The electrophotographic photoreceptors of the above Examples and Comparative Examples were charged and exposed in the same manner as in the sensitivity characteristic test (1) using a drum sensitivity tester manufactured by GENTEC. Is performed, a static elimination lamp (wavelength 660n)
m), the charge on the surface of the photoreceptor was removed. This charge-exposure-discharge process is repeated 2,000 times continuously,
At that time, the surface potential V ₀ (V), the half-exposure amount E _1/2 (μJ /
cm ² ) and the residual potential Vr (V) were measured, and the stability was evaluated based on the change from the initial value. At this time, the rotation speed of the photosensitive drum was set to 40 rpm. <Solvent resistance test (1)> In order to check the adhesion between the surface protective layer and the organic photosensitive layer, methanol was dropped on the surface of the electrophotographic photosensitive member of each of Examples and Comparative Examples with a dropper. The presence or absence of peeling and cracks was confirmed.

：: There was no change on the surface of the photoreceptor.

Δ: There were some cracks but no peeling.

×: Peeling of the surface protective layer was observed.

Tables 1 and 2 show the above results.

[0132]

[Table 1]

[0133]

[Table 2]

From the table, the photoconductors of Comparative Examples 1 and 2, which did not use the diindenopyrazine derivative represented by the above formula (1), showed peeling or cracking of the photoconductor in a solvent resistance test. On the other hand, it was found that the effect of improving the physical stability of the inorganic surface protective layer could not be obtained.

It was also found that the photoreceptor of the comparative example had a high residual potential after exposure and a large half-reduction exposure amount, so that the sensitivity was greatly reduced when the surface protective layer was formed. Furthermore, in the photoreceptor of the comparative example, the residual potential and the half-exposure amount were remarkably increased in the repetition test.

On the other hand, in all of the photoreceptors of Examples 1 to 8, in the solvent resistance test, no crack or peeling was observed on the surface protective layer. And from this,
It was confirmed that by using a diindenopyrazine derivative, the physical stability of the inorganic surface protective layer could be improved and the durability of the photoreceptor could be improved more than before.

In each of the photoreceptors of the above Examples, the residual potential after exposure was low, and the half-reduction exposure amount was small. Therefore, the sensitivity did not decrease significantly when the surface protective layer was formed. Since the change in the value was small thereafter, it was also confirmed that the film had good sensitivity even at the initial and repeated copying. [Examples 9 to 12, Comparative Example 3] On the surface of the single-layer type photosensitive layer,
Instead of the silicon-carbon composite film, by the following steps,
Examples 13 to 18 and Comparative Example 3 were performed in the same manner as in Examples 1 to 4 and Comparative Example 1 except that a surface protective layer having a thickness of 0.5 μm made of amorphous carbon (C) was formed. An electrophotographic photoreceptor was manufactured. <Formation of surface protective layer> After the aluminum tube on which the single-layer type photosensitive layer was formed was set in the chamber of the plasma CVD apparatus, the vacuum was evacuated to an ultimate vacuum of 0.67 Pa, and the heater of the apparatus was used. The temperature of the raw tube was adjusted to 50 ° C.

Next, methane gas (C
H ₄ ) and hydrogen gas (H ₂ ) were supplied at the following flow rates to adjust the degree of vacuum to 0.47 hPa.

Methane gas: 300 SCCM Hydrogen gas: 300 SCCM Next, in this state, a frequency of 13.56 MH was introduced into the chamber.
z, a high-frequency electric field of output 200 W is applied to generate glow discharge, and amorphous carbon (C) is formed on the surface of the single-layer photosensitive layer at a deposition rate of 0.15 μm / hr by plasma CVD. ), And a surface protective layer having the above thickness was formed. [Examples 13 to 16, Comparative Example 4] Instead of the silicon-carbon composite film on the surface of the laminated photosensitive layer, Examples 13 to 1 were used.
8. In the same manner as in Examples 5 to 8 and Comparative Example 2, except that a 0.5 μm-thick surface protective layer made of amorphous carbon (C) was formed in the same steps as Comparative Example 3, Was manufactured.

With respect to the electrophotographic photosensitive members of each of the above Examples and Comparative Examples, the same sensitivity characteristic test (1) and durability test (1) were performed as described above, and the characteristics were evaluated. Table 3 shows the results
And Table 4.

[0141]

[Table 3]

[0142]

[Table 4]

From the table, it was confirmed that the same results as described above were obtained based on the constitution of the single-layer type photosensitive layer as the base, even if the type of the surface protective layer was changed.

That is, the photoreceptors of Comparative Examples 3 and 4 which did not use the diindenopyrazine derivative represented by the above formula (1) showed peeling of the photoreceptors in a solvent resistance test, and showed that It was found that the effect of improving the physical stability of the surface protective layer was not obtained.

It was also found that the photoreceptor of the comparative example had a high residual potential after exposure and a large half-reduction exposure amount, so that the sensitivity was greatly reduced when the surface protective layer was formed. Furthermore, in the photoreceptor of the comparative example, the residual potential and the half-exposure amount were remarkably increased in the repetition test.

On the other hand, in all of the photosensitive members of Examples 9 to 16, no cracks or peeling were observed in the surface protective layer in the solvent resistance test. From this, it was confirmed that by using the diindenopyrazine derivative, the physical stability of the inorganic surface protective layer could be improved, and the durability of the photoreceptor could be improved more than before.

In each of the photoreceptors of the above Examples, the residual potential after exposure was low, and the half-reduction exposure amount was small, so that the sensitivity did not greatly decrease when the surface protective layer was formed. Since the change in the value was small thereafter, it was also confirmed that the sensitivity was good even at the initial and repeated copying. [Examples 17 and 18, Comparative Example 5] The thickness of an amorphous silicon-nitrogen (SiN) composite film formed on the surface of a single-layer type photosensitive layer by the following steps instead of the silicon-carbon composite film. Examples 17 and 8 were performed in the same manner as in Examples 5 and 8 and Comparative Example 2 except that a 0.5 μm surface protection layer was formed.
18. An electrophotographic photoreceptor of Comparative Example 5 was produced. <Formation of surface protective layer> After the aluminum tube on which the single-layer type photosensitive layer was formed was set in the chamber of the plasma CVD apparatus, the vacuum was evacuated to an ultimate vacuum of 0.67 Pa, and the heater of the apparatus was used. The temperature of the raw tube was adjusted to 50 ° C.

Next, silane gas (SiH
₄ ) A nitrogen gas (N ₂ ) and a hydrogen gas (H ₂ ) were supplied at the following flow rates to adjust the degree of vacuum to 0.47 hPa.

Silane gas: 15 SCCM Nitrogen gas: 150 SCCM Hydrogen gas: 75 SCCM Next, in this state, a frequency of 13.56 MH was introduced into the chamber.
z, a glow discharge is generated by applying a high-frequency electric field having an output of 150 W, and a silicon-nitrogen (SiN) composite is formed on the surface of the single-layer photosensitive layer at a deposition rate of 0.75 μm / hr by a plasma CVD method. A surface protective layer composed of a film and having the above thickness was formed. [Examples 19 and 20, Comparative Example 6] The thickness of an amorphous carbon-nitrogen (CN) composite film formed on the surface of a single-layer type photosensitive layer by the following process instead of the silicon-carbon composite film. Except that a 0.5 μm surface protection layer was formed, the same procedures as in Examples 5 and 8 and Comparative Example 2 were carried out to obtain Examples 19 and 20, respectively.
20 and Comparative Example 6 were produced. <Formation of surface protective layer> After the aluminum tube on which the single-layer type photosensitive layer was formed was set in the chamber of the plasma CVD apparatus, the vacuum was evacuated to an ultimate vacuum of 0.67 Pa, and the heater of the apparatus was used. The temperature of the raw tube was adjusted to 50 ° C.

Next, methane gas (C
H ₄ ), nitrogen gas (N ₂ ) and hydrogen gas (H ₂ ) were supplied at the following flow rates to adjust the degree of vacuum to 0.47 hPa.

Methane gas: 100 SCCM Nitrogen gas: 150 SCCM Hydrogen gas: 100 SCCM Next, in this state, a frequency of 13.56 MH was introduced into the chamber.
A glow discharge is generated by applying a high-frequency electric field having an output of 150 watts and a carbon-nitrogen (CN) composite is formed on the surface of the single-layer type photosensitive layer at a deposition rate of 0.10 μm / hr by plasma CVD. A surface protective layer composed of a film and having the above thickness was formed. [Examples 21 and 22, Comparative Example 7] The thickness of an amorphous carbon-boron (CB) composite film on the surface of a single-layer type photosensitive layer by the following process instead of the silicon-carbon composite film. Example 21 was repeated in the same manner as in Examples 5 and 8 and Comparative Example 2 except that a surface protection layer of 0.5 μm was formed.
22. An electrophotographic photoreceptor of Comparative Example 7 was produced. <Formation of surface protective layer> After the aluminum tube on which the single-layer type photosensitive layer was formed was set in the chamber of the plasma CVD apparatus, the vacuum was evacuated to an ultimate vacuum of 0.67 Pa, and the heater of the apparatus was used. The temperature of the raw tube was adjusted to 50 ° C.

Next, methane gas (C
H ₄ ), diborane gas (B ₂ H ₆ ) and hydrogen gas (H ₂ )
Are supplied at the following flow rates, and the degree of vacuum is 0.47 h.
It was adjusted to Pa.

Methane gas: 100 SCCM Diborane gas: 200 SCCM Hydrogen gas: 100 SCCM Next, in this state, a frequency of 13.56 MH was introduced into the chamber.
A glow discharge is generated by applying a high-frequency electric field having an output of 150 watts and a carbon-boron (CB) composite is formed on the surface of the single-layer type photosensitive layer at a deposition rate of 0.10 μm / hr by a plasma CVD method. A surface protective layer composed of a film and having the above thickness was formed. [Examples 23 and 24, Comparative Example 8] The thickness of an amorphous carbon-fluorine (CF) composite film formed on the surface of a single-layer photosensitive layer by the following process in place of the silicon-carbon composite film. Except that a 0.5 μm surface protection layer was formed, the same procedures as in Examples 5 and 8 and Comparative Example 2 were performed, and
24. An electrophotographic photoreceptor of Comparative Example 8 was produced. <Formation of surface protective layer> After the aluminum tube on which the single-layer type photosensitive layer was formed was set in the chamber of the plasma CVD apparatus, the vacuum was evacuated to an ultimate vacuum of 0.67 Pa, and the heater of the apparatus was used. The temperature of the raw tube was adjusted to 50 ° C.

Next, methane gas (C
H ₄ ), carbon tetrafluoride gas (CF ₄ ) and hydrogen gas (H
₂ ) are supplied at the following flow rates to reduce the vacuum to 0.4
It was adjusted to 7 hPa.

Methane gas: 100 SCCM Carbon tetrafluoride gas: 100 SCCM Hydrogen gas: 100 SCCM Next, in this state, a frequency of 13.56 MH was introduced into the chamber.
A glow discharge is generated by applying a high-frequency electric field having an output of 150 watts and a carbon-fluorine (CF) composite is formed on the surface of the single-layer photosensitive layer at a deposition rate of 0.10 μm / hr by a plasma CVD method. A surface protective layer composed of a film and having the above thickness was formed. [Examples 25 and 26, Comparative Example 9] The thickness of an amorphous boron-nitrogen (BN) composite film formed on the surface of a single-layer type photosensitive layer by the following process instead of the silicon-carbon composite film. Example 25, Example 25, and Comparative Example 2 except that a 0.5 μm surface protective layer was formed.
26. An electrophotographic photoreceptor of Comparative Example 9 was produced. <Formation of surface protective layer> After the aluminum tube on which the single-layer type photosensitive layer was formed was set in the chamber of the plasma CVD apparatus, the vacuum was evacuated to an ultimate vacuum of 0.67 Pa, and the heater of the apparatus was used. The temperature of the raw tube was adjusted to 50 ° C.

Next, diborane gas (B ₂
H ₆ ), nitrogen gas (N ₂ ) and hydrogen gas (H ₂ ) were supplied at the following flow rates to adjust the degree of vacuum to 0.47 hPa.

Diborane gas: 200 SCCM Nitrogen gas: 150 SCCM Hydrogen gas: 150 SCCM Then, in this state, a frequency of 13.56 MH was introduced into the chamber.
A glow discharge is generated by applying a high-frequency electric field having an output of 150 watts and a boron-nitrogen (BN) composite is formed on the surface of the single-layer photosensitive layer at a deposition rate of 0.08 μm / hr by a plasma CVD method. A surface protective layer composed of a film and having the above thickness was formed.

With respect to the electrophotographic photosensitive members of each of the above Examples and Comparative Examples, the same sensitivity characteristic test (1) and durability test (1) were performed as described above, and the characteristics were evaluated. Table 3 shows the results
Shown in

[0159]

[Table 5]

From the table, it was confirmed that even when the type of the surface protective layer was further changed, the same result as described above was obtained based on the structure of the single-layer type photosensitive layer as the underlayer.

That is, in the photoconductors of Comparative Examples 5 to 9 which did not use the diindenopyrazine derivative represented by the above formula (1), peeling or cracking of the photoconductor was recognized in the solvent resistance test. It was found that the effect of improving the physical stability of the inorganic surface protective layer could not be obtained.

It was also found that the photoreceptor of the comparative example had a high residual potential after exposure and a large half-reduction exposure amount, so that the sensitivity was greatly reduced when the surface protective layer was formed. Furthermore, in the photoreceptor of the comparative example, the residual potential and the half-exposure amount were remarkably increased in the repetition test.

On the other hand, in all of the photoconductors of Examples 17 to 26, no cracks or peeling were observed on the surface protective layer in the solvent resistance test. From this, it was confirmed that by using the diindenopyrazine derivative, the physical stability of the inorganic surface protective layer could be improved, and the durability of the photoreceptor could be improved more than before.

In each of the photoreceptors of the above Examples, the residual potential after exposure was low, and the half-reduction exposure amount was small. Therefore, when the surface protective layer was formed, the sensitivity did not decrease significantly. Since the change in the value was small thereafter, it was also confirmed that the film had good sensitivity even at the initial and repeated copying. Example 27 <Formation of Laminated Photosensitive Layer> 2.5 parts by weight of an X-type metal-free phthalocyanine crystal represented by the above formula (CG-1) as a charge generating agent and polyvinyl butyral as a binder resin 1 part by weight and 15 parts by weight of tetrahydrofuran were mixed and dispersed using a ball mill to prepare a coating liquid for a charge generation layer in the laminated photosensitive layer.

Next, this coating solution was applied on an aluminum tube as a conductive substrate by a dip coating method, and dried at 110 ° C. for 30 minutes with hot air to obtain a film thickness of 0.5.
A μm charge generation layer was formed.

Next, a combination of a hole transporting agent and a binder resin,
Polyvinylcarbazole having a repeating unit represented by the formula (HT-1) (number average molecular weight Mn = 9500)
1 part by weight, 0.2 parts by weight of the diindenopyrazine derivative represented by the formula (1-1) as an electron transporting agent, and 10 parts by weight of tetrahydrofuran were mixed and dispersed using a ball mill together with 10 parts by weight. A coating liquid for a charge transport layer was prepared from the laminated photosensitive layer.

Then, this coating solution was applied on the above-mentioned charge generating layer by a dip coating method.
Then, the film was dried with hot air for 20 minutes to form a charge transport layer having a thickness of 20 μm, thereby forming a negatively charged laminated photosensitive layer. <Formation of Surface Protective Layer> On the laminated photosensitive layer formed as described above, plasma CVD was performed under the same conditions as in Example 1 above.
A 0.5 μm-thick surface protective layer made of an amorphous silicon-carbon (SiC) composite film was formed by a method, to produce an electrophotographic photosensitive member of Example 35. [Examples 28 to 30] Table 6 as electron transporting agents, respectively
The electrophotographic photoreceptors of Examples 28 to 30 were produced in the same manner as in Example 27 except that 0.2 parts by weight of the diindenopyrazine derivative represented by the formula number shown in the following formula was used. [Comparative Example 10] In the same manner as in Example 27 except that no diindenopyrazine derivative was used as an electron transporting agent,
An electrophotographic photosensitive member of Comparative Example 10 was manufactured. [Examples 31 to 34, Comparative Example 11] Instead of polyvinyl carbazole having a repeating unit represented by the formula (HT-1) and serving as a hole transporting agent and a binder resin, a hole transporting agent was used. Examples 27 to 30, except that 0.8 parts by weight of diethylaminobenzaldehyde diphenylhydrazone represented by the formula (HT-3) and 1 part by weight of a Z-type polycarbonate (weight average molecular weight 20,000) as a binder resin were used. In the same manner as in Comparative Example 10, the electrophotographic photosensitive members of Examples 31 to 34 and Comparative Example 11 were produced. <Sensitivity characteristic test (2)> With respect to the electrophotographic photosensitive members of the above Examples and Comparative Examples, an applied voltage was applied to the surface of each photosensitive member using a drum sensitivity tester manufactured by GENTEC, and a grid voltage was applied. Adjust the surface to -800 ±
After charging to 20 V, the surface potential V ₀ (V) was measured.

Next, a white light of a halogen lamp, which is an exposure light source of the testing machine, was used to obtain a wavelength 7
Light intensity 10 μW monochromatized to 80 nm and half-width 20 nm
When the surface of the electrophotographic photoreceptor is irradiated with monochromatic light of 1 cm / cm ² for 1 second, the time required for the surface potential V ₀ (V) to become １ ／ is measured, and half-exposure is performed. Quantity E _1/2 (μ
J / cm ² ). Further, the surface potential at the time when 0.5 seconds had elapsed from the start of exposure was measured as a residual potential Vr (V). <Repeated test (2)> The electrophotographic photoreceptors of the above Examples and Comparative Examples were charged and exposed in the same manner as in the sensitivity characteristic test (1) using a drum sensitivity tester manufactured by GENTEC. Is performed, a static elimination lamp (wavelength 660n)
m), the charge on the surface of the photoreceptor was removed. This charge-exposure-discharge process is repeated 2,000 times continuously,
At that time, the surface potential V ₀ (V), the half-exposure amount E _1/2 (μJ /
cm ² ) and the residual potential Vr (V) were measured, and the stability was evaluated based on the change from the initial value. At this time, the rotation speed of the photosensitive drum was set to 40 rpm. <Solvent resistance test (2)> In order to examine the adhesion between the surface protective layer and the organic photosensitive layer, methanol was dropped on the surface of the electrophotographic photosensitive member of each of Examples and Comparative Examples with a dropper. The presence or absence of peeling and cracks was confirmed.

A: No change was observed on the surface of the photoreceptor.

Δ: There were some cracks, but no peeling was observed.

×: Peeling of the surface protective layer was observed.

Tables 6 and 7 show the above results.

[0173]

[Table 6]

[0174]

[Table 7]

From the table, it was confirmed that the same results as described above were obtained based on the structure of the charge transporting layer which is the outermost surface even when the single-layer type photosensitive layer was replaced with the laminated type photosensitive layer.

That is, the photoreceptors of Comparative Examples 10 and 11 which did not use the diindenopyrazine derivative represented by the above formula (1) showed peeling of the photoreceptors in a solvent resistance test, It was found that the effect of improving the physical stability of the surface protective layer was not obtained.

It was also found that the photoreceptor of the comparative example had a high residual potential after exposure and a large half-reduction exposure amount, so that the sensitivity was greatly reduced when the surface protective layer was formed. Furthermore, in the photoreceptor of the comparative example, the residual potential and the half-exposure amount were remarkably increased in the repetition test.

On the other hand, in all of the photoreceptors of Examples 27 to 34, no crack or peeling was observed in the surface protective layer in the solvent resistance test. From this, it was confirmed that by using the diindenopyrazine derivative, the physical stability of the inorganic surface protective layer could be improved, and the durability of the photoreceptor could be improved more than before.

In each of the photoreceptors of the above examples, the residual potential after exposure was low, and the half-reduction exposure amount was small. Therefore, the sensitivity did not decrease significantly when the surface protective layer was formed. Since the change in the value was small thereafter, it was also confirmed that the sensitivity was good even at the initial and repeated copying. [Examples 35 to 38, Comparative Example 12] Instead of the silicon-carbon composite film on the surface of the laminated photosensitive layer, Examples 9 to 1 were used.
2. Except that a 0.5 μm-thick surface protective layer made of amorphous carbon (C) was formed in the same steps as in Comparative Example 3, the same procedures as in Examples 27 to 30 and Comparative Example 10 were performed. Was manufactured. [Examples 39 to 42, Comparative example 13] Instead of the silicon-carbon composite film on the surface of the laminated photosensitive layer, examples 9 to 1 were applied.
2. Except that a 0.5 μm-thick surface protective layer made of amorphous carbon (C) was formed in the same process as in Comparative Example 3, the same procedures as in Examples 41 to 46 and Comparative Example 11 were performed. Was manufactured.

With respect to the electrophotographic photosensitive members of the above Examples and Comparative Examples, the same sensitivity characteristic test (2) and durability test (2) as described above were performed, and the characteristics were evaluated. Table 8 shows the results.
And Table 9 below.

[0181]

[Table 8]

[0182]

[Table 9]

From the table, it was confirmed that even when the type of the surface protective layer was changed, the same result as described above was obtained based on the structure of the charge transport layer in the laminated photosensitive layer as the base.

That is, the photoconductors of Comparative Examples 12 and 13 which did not use the diindenopyrazine derivative represented by the formula (1) showed peeling of the photoconductors in a solvent resistance test, It was found that the effect of improving the physical stability of the surface protective layer was not obtained.

It was also found that the photoreceptor of the comparative example had a high residual potential after exposure and a large half-reduction exposure amount, so that the sensitivity was greatly reduced when the surface protective layer was formed. Furthermore, in the photoreceptor of the comparative example, the residual potential and the half-exposure amount were remarkably increased in the repetition test.

On the other hand, in all of the photoreceptors of Examples 35 to 42, in the solvent resistance test, no crack or peeling was observed on the surface protective layer. From this, it was confirmed that by using the diindenopyrazine derivative, the physical stability of the inorganic surface protective layer could be improved, and the durability of the photoreceptor could be improved more than before.

In each of the photoreceptors of the above Examples, the residual potential after exposure was low, and the half-reduction exposure amount was small. Therefore, the sensitivity did not decrease significantly when the surface protective layer was formed. Since the change in the value was small thereafter, it was also confirmed that the film had good sensitivity even at the initial and repeated copying. [Examples 43 and 44, Comparative example 14] Instead of the silicon-carbon composite film on the surface of the laminated type photosensitive layer, Examples 17 and 1
8. Same as Examples 31, 34 and Comparative Example 11 except that a 0.5 μm-thick surface protective layer made of an amorphous silicon-nitrogen (SiN) composite film was formed by the same steps as Comparative Example 5. Then, each electrophotographic photoreceptor was manufactured. [Examples 45 and 46, Comparative Example 15] Instead of the silicon-carbon composite film on the surface of the laminated type photosensitive layer, Examples 19 and 2
0, similar to Examples 31 and 34 and Comparative Example 11 except that a 0.5 μm-thick surface protective layer made of an amorphous carbon-nitrogen (CN) composite film was formed by the same steps as Comparative Example 6. Then, each electrophotographic photoreceptor was manufactured. [Examples 47 and 48, Comparative example 16] Instead of the silicon-carbon composite film on the surface of the laminated photosensitive layer, examples 21 and 2 were used.
2. Same as Examples 31, 34 and Comparative Example 11 except that a 0.5 μm-thick surface protective layer made of an amorphous carbon-boron (CB) composite film was formed by the same process as Comparative Example 7. Then, each electrophotographic photoreceptor was manufactured. [Examples 49 and 50, Comparative Example 17] Instead of the silicon-carbon composite film on the surface of the laminated type photosensitive layer, Examples 23 and 2
4. Same as Examples 31, 34 and Comparative Example 11 except that a 0.5 μm-thick surface protective layer made of an amorphous carbon-fluorine (CF) composite film was formed by the same steps as Comparative Example 8. Then, each electrophotographic photoreceptor was manufactured. [Examples 51 and 52, Comparative Example 18] Instead of the silicon-carbon composite film on the surface of the laminated photosensitive layer, Examples 25 and
6. Same as Examples 31 and 34 and Comparative Example 11 except that a 0.5 μm-thick surface protective layer made of an amorphous boron-nitrogen (BN) composite film was formed by the same steps as Comparative Example 9. Then, each electrophotographic photoreceptor was manufactured.

With respect to the electrophotographic photosensitive members of the above Examples and Comparative Examples, the same sensitivity characteristic test (2) and durability test (2) were performed as described above, and the characteristics were evaluated. Table 1 shows the results
0 is shown.

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From the table, it was confirmed that even if the type of the surface protective layer was further changed, the same result as described above was obtained based on the structure of the charge transport layer in the laminated photosensitive layer as the underlayer.

That is, in the photoconductors of Comparative Examples 14 to 18 which did not use the diindenopyrazine derivative represented by the above formula (1), peeling or cracking of the photoconductor was observed in the solvent resistance test. It was found that the effect of improving the physical stability of the inorganic surface protective layer could not be obtained.

It was also found that the photoreceptor of the comparative example had a high residual potential after exposure and a large half-reduction exposure amount, so that the sensitivity was greatly reduced when the surface protective layer was formed. Furthermore, in the photoreceptor of the comparative example, the residual potential and the half-exposure amount were remarkably increased in the repetition test.

On the other hand, in all of the photoreceptors of Examples 43 to 52, in the solvent resistance test, no crack or peeling was observed on the surface protective layer. From this, it was confirmed that by using the diindenopyrazine derivative, the physical stability of the inorganic surface protective layer could be improved, and the durability of the photoreceptor could be improved more than before.

In each of the photoreceptors of the above Examples, the residual potential after exposure was low and the amount of half-exposure exposure was small, so that the sensitivity did not decrease significantly when the surface protective layer was formed. Since the change in the value was small thereafter, it was also confirmed that the sensitivity was good even at the initial and repeated copying.

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 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideaki Fukunaga 1166, Haseno, Hachimizo-cho, Yokaichi-shi, Shiga Prefecture F-term (reference) 2H068 AA02 AA20 AA31 AA37 BA16 CA03 CA05 CA60 EA24 FA01 FA08 FA19 FB01 FB05

Claims (5)

[Claims] An electrophotographic photosensitive member comprising an organic photosensitive layer and an inorganic surface protective layer laminated in this order on a conductive substrate,
At least the outermost surface portion of the organic photosensitive layer in contact with the surface protective layer has the formula (1): [Wherein, R ^{1 to} R ³ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, n and m are the same or different and are integers of 0 to 4, p is Shows an integer of 0 to 5. ] Or
Formula (2): [In the formula, R ^{4 to} R ⁵ are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group or an aralkyl group, and q and r are the same or different and represent an integer of 0 to 4. An electrophotographic photoreceptor comprising a diindenopyrazine derivative represented by the following formula: 2. The electrophotographic photosensitive member according to claim 1, wherein the surface protective layer is a layer formed by a vapor deposition method. 3. The method according to claim 1, wherein the surface protective layer is made of at least one element selected from the group consisting of metal elements and carbon, or an inorganic compound containing these elements. Electrophotographic photoreceptor. 4. An organic photosensitive layer comprising, in a binder resin, a charge generating agent, a hole transporting agent, and a diindenopyrazine derivative represented by the formula (1) or (2) as an electron transporting agent. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is a single-layer type photosensitive layer containing: 5. An organic photosensitive layer comprising a charge generating layer containing a charge generating agent, a hole transporting agent in a binder resin, and formula (1) or (2) as an electron transporting agent. The electrophotographic photoreceptor according to claim 1, wherein the photoreceptor is a laminated photosensitive layer in which a charge transport layer containing a diindenopyrazine derivative is laminated in this order.