JPH0588381A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body with high sensitivity and small residual potential. CONSTITUTION:In a laminated electrophotographic sensitive body formed by at least laminating a charge generating layer containing a charge generating material and a charge transfer layer containing a charge transfer material on an electrically conductive substrate or a monolayer photographic sensitive body containing a charge generating material and a charge transfer material, the electrophotographic sensitive body is characterized in that a fluorescent intensity ratio of the photosensitive body measured under the electric field of 100V/mum or in the state where both time external or internal electric fields are not applied and represented by the formula (1) is <=0.9. eta=IGT/IG...(1) where eta= fluorescent intensity ratio, IG = fluorescent intensity of charge generating material in charge generating layer monolayer in the photosensitive body, and IGT = fluorescent intensity of charge generating material when laminating charge generating layer and charge transfer layer in the photosensitive body.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor.

[0002]

2. Description of the Related Art As a discussion of the carrier generation mechanism of an electrophotographic photoreceptor, J. Am. Chem. Soc. 198
0, 102, P.I. 4967 to 4970, which discuss the generation of carriers at the CGL / Al interface due to the internal electric field due to the Schottky barrier.

[0003]

As a result of further research on the carrier generation mechanism, the present invention provides an extremely high-sensitivity electrophotographic photosensitive member by utilizing a carrier generated by a mechanism different from the conventional technique. Is what you are trying to do.

[0004]

The constitution of the present invention for solving the above-mentioned problems is an electrophotographic photosensitive member as described in the claims.

In the organic electrophotographic photosensitive member, the high sensitivity is an important point. However, as a result of various investigations by the present inventors, in the organic electrophotographic photosensitive member, the fluorescence intensity ratio shown above was obtained. The inventors have found that those having η of 0.9 or less have extremely high sensitivity, and have completed the present invention.

First, a brief description will be given on how to increase the sensitivity of the photoconductor.

In the case of an organic electrophotographic photosensitive member, there are two points for increasing the sensitivity. One is to increase carrier mobility, and the other is to increase quantum efficiency. The present invention is aimed at the latter of the above.

In order to increase the quantum efficiency, it is desirable to set the carrier generation efficiency, carrier injection efficiency, and carrier transport efficiency closer to 1, respectively, but at present, the other two except carrier transport efficiency are set to 1. Is far from.

As a result of various studies on the carrier generation / injection process of the organic electrophotographic photosensitive member, the present inventors have found that the carrier generation / injection efficiency greatly changes depending on the combination of materials, and the organic electrophotographic photosensitive member It was revealed that the carrier generation / injection process occurs by the electron transfer reaction between the charge generation material and the charge transport material. In particular, it was revealed that the carrier generation efficiency is related to the degree of quenching by the charge transport material (the fluorescence intensity ratio of I _G and I _GT ) with respect to the fluorescence spectrum intensity of the charge generation material. It was found that carriers with high extinction degree have high carrier generation / injection efficiency. That is, in the combination of I _G / I _GT of 0.9 or less, the carrier generation efficiency is relatively high,
The inventors have found that the photosensitive member has high sensitivity, and have completed the present invention.

Next, the method of measuring I _G and I _GT shown above will be briefly described.

A commercially available fluorescence spectrophotometer can be used for a material having a relatively high fluorescence quantum efficiency, although it depends on the fluorescence quantum efficiency of the charge generating substance.

On a suitable substrate (for example, NESA glass), a sample of charge generating layer single layer and a sample of charge generating layer and charge transporting layer are respectively prepared (in this case, the charge generating layer has the same thickness). Alternatively, a counter electrode may be provided if necessary.) Excitation with light having a wavelength that excites only the charge generating substance, the fluorescence spectrum may be measured, and the intensities may be compared.

In the case of a material having a relatively small fluorescence quantum efficiency,
Measurement can be performed by preparing a sample in the same manner as above and using a light source having a suitable power (such as a laser) in combination with a suitable highly sensitive detector or lock-in amplifier.

The internal electric field is, for example, Al and X-Meta.
An example thereof is a Schottky barrier that is generated at the interface between the 1-Free Phthalocyanine and the one when it is joined.

In the present invention, the fluorescence spectrum is measured with a sample structure that does not generate an internal electric field.

Further, preferably, neither the charge generating layer nor the charge transporting layer is in contact with the electrodes, and the fluorescence spectrum is measured in a state where no external electric field is applied.

It is more preferable that a transparent substrate is used, and that the measurement can be performed by irradiating the excitation light for fluorescence spectrum measurement from either direction of the charge generation layer or the charge transport layer.

Next, the present invention will be specifically described with reference to the drawings.

FIGS. 1 and 2 are sectional views showing a constitutional example of a photosensitive member used in the present invention as defined in claims 1 to 3, wherein a photosensitive layer 15 is provided on a conductive support 11. The photosensitive layer is formed by stacking a charge generation layer 21 and a charge transport layer 23.

FIG. 3 is a cross-sectional view showing a structural example of a photosensitive member used in the present invention as defined in claim 4, which has a single photosensitive layer 15 on a conductive support 11.

4 and 5 are cross-sectional views showing another structural example. FIG. 4 shows an undercoat layer 13 provided between a conductive support 11 and a photosensitive layer 15, and FIG. 5 shows a photosensitive layer. A protective layer 17 is provided on top of 15. Here, it is also possible to provide an intermediate layer (not shown) between the photosensitive layer 15 and the protective layer 17.

As the conductive support 11, the volume resistance 10
^A material exhibiting conductivity of ¹⁰ Ωcm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum, or a metal oxide such as tin oxide or indium oxide, which is formed into a film or by vapor deposition or sputtering. Cylindrical plastic, paper coated with aluminum, aluminum, aluminum alloy, nickel, stainless steel, etc. I. , I. I. A tube or the like which has been surface-treated by cutting, superfinishing, polishing or the like can be used after being made into a raw tube by a method such as extrusion or drawing.

Next, the charge generation layer 21 will be described. The charge generation layer 21 is a layer containing a charge generation material as a main component, and a binder resin may be used if necessary.

As the binder resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, etc. are used. Be done.

A known material can be used as the charge generating substance. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azurenium salt pigment, squaric acid methine pigment, azo pigment having a carbazole skeleton, azo pigment having a triphenylamine skeleton, azo pigment having a diphenylamine skeleton,
Azo pigments having a dibenzothiophene skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a fluorenone skeleton, azo pigments having a bisstilbene skeleton, azo pigments having a distyryloxadiazole skeleton, azo having a distyrylcarbazole skeleton Pigments, perylene pigments, anthraquinone pigments or polycyclic quinone pigments, quinone imine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, bisbenzimidazole pigments, etc. Can be mentioned.

Above all, the azo pigment is effective.

Next, the charge transport layer 23 will be described.

The charge transport layer 23 can be formed by dissolving or dispersing a charge transport substance and a binder resin in a suitable solvent, coating and drying the solution.

The charge transport material includes a hole transport material and an electron transport material.

Examples of the electron transporting substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone. , 2,4,5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Examples thereof include electron-accepting substances such as trinitro-4H-indeno {1,2-b} thiophen-4-one and 1,3,7-trinitrodibenzothiophenone-5,5-dioxide.

Examples of the hole-transporting substance include the electron-donating substances shown below, which are preferably used. For example, poly-N-vinylcarbazole and its derivative, poly-γ-carbazolylethylglutamate and its derivative, pyrene-formaldehyde condensate and its derivative, polyvinylpyrene, polyvinylphenanthrene, oxazole derivative, oxadiazole derivative, imidazole derivative, Triphenylamine derivative, 9- (p-diethylaminostyryl) anthracene, 1,1-bis-
(4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, etc. Can be mentioned.

The binder used in the charge transport layer is polycarbonate (bisphenol A type, bisphenol Z type), polyester, methacrylic resin, acrylic resin, polyethylene, vinyl chloride, vinyl acetate, polystyrene, phenol resin, epoxy resin, polyurethane. , Polyvinylidene chloride, alkyd resin, silicone resin, polyvinyl carbazole, polyvinyl butyral,
Polyvinyl formal, polyacrylate, polyacrylamide, polyamide, phenoxy resin and the like are used. These binders can be used alone or as a mixture of two or more kinds.

When the photosensitive layer 15 is a single layer, the layer contains at least the above-mentioned charge generating substance and charge transporting substance.

The subbing layer 13 provided between the support 11 and the charge generation layer 21 is provided for the purpose of further improving the effect of the present invention and improving the adhesiveness, and its material is SiO, Al ₂ Inorganic materials such as O ₃ , silane coupling agents, titanium coupling agents, and chromium coupling agents, polyamide resins, alcohol-soluble polyamide resins, water-soluble polyvinyl butyral, polyvinyl butyral, PV
A binder resin having good adhesiveness such as A is used.
In addition, ZnO, TiO ₂ , Z is added to the resin having good adhesiveness.
A dispersion of nS or the like can also be used. As a method for forming the undercoat layer, a method such as sputtering or vapor deposition is used when an inorganic material is used alone, and a usual coating method is used when an organic material is used. The thickness of the undercoat layer is appropriately 5 μm or less.

The protective layer 17 is provided for the purpose of protecting the surface of the photoconductor, and the materials used therefor are ABS resin and A
CS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene, Polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene,
Examples thereof include resins such as polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. The protective layer may be made of a fluororesin such as polytetrafluoroethylene, a silicone resin, or a dispersion of an inorganic material such as titanium oxide, tin oxide or potassium titanate in these resins for the purpose of improving wear resistance. It can be added. As a method for forming the protective layer, a usual coating method is adopted. It is suitable that the protective layer has a thickness of about 0.5 to 10 μm. Further, in the present invention, it is possible to provide another intermediate layer (not shown) between the charge transport layer 23 and the protective layer 17.

[0036]

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

All parts used in the examples represent parts by weight.

Example I-1 On a polyethylene terephthalate film on which aluminum was vapor-deposited, a charge generating layer coating liquid and a charge transporting layer coating liquid having the following compositions were sequentially applied and dried to obtain a 0.2 μm thick charge. Forming a generator layer and a 22 μm thick charge transport layer,
An electrophotographic photoreceptor of the present invention was produced.

Charge Generating Layer Coating Solution 5 parts of charge generating substance having the following structure

[0040]

[Chemical 1]

Polyvinyl butyral resin {Denki Kagaku Kogyo KK: Denkabutyral # 4000-1} 1 part Cyclohexanone 230 parts 2-butanone 120 parts Charge transport layer coating liquid 9 parts Charge transport material having the following structure

[0042]

[Chemical 2]

Polycarbonate {Teijin Kasei Co., Ltd .: Panlite L-1250} 10 parts Tetrahydrofuran 100 parts Further, on the NESA glass substrate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample I-1) and the charge generation layer After coating each of the charge transport layer stacks (Sample I-2),
As a counter electrode, Al was vapor-deposited at about 500Å to prepare a sample.

Example I-2 An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions were applied and dried on the same support as in Example I-1 in this order. Undercoat layers of 0.3 μm each, and 0.
A 2 μm thick charge generation layer and a 22 μm thick charge transport layer were formed to prepare an electrophotographic photoreceptor of the present invention.

Undercoat layer coating liquid 25% water-soluble polyvinyl butyral aqueous solution {Sekisui Chemical Co., Ltd .: S-REC W-201} 40 parts Water 150 parts Methanol 200 parts Charge generating layer coating liquid Charge generating substance 4 having the following structure 4 Department

[0046]

[Chemical 3]

Cyclohexanone 100 parts 2-butanone 50 parts Charge transport layer coating liquid 8 parts charge transport material having the following structure

[0048]

[Chemical 4]

Polycarbonate {Teijin Kasei Co., Ltd .: Panlite K-1300} 10 parts Methylene chloride 100 parts Further, on the NESA glass substrate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample I-3) charge generation layer And a charge transport layer stack (Sample I-4), respectively,
As a counter electrode, Al was vapor-deposited at about 500Å to prepare a sample.

Example I-3 On a polyethylene terephthalate film provided with a Hastelloy conductive layer, an undercoat layer coating solution, a charge generating layer coating solution, and a charge transporting layer coating solution having the following compositions were sequentially applied and dried. Then, an undercoating layer having a thickness of 2 μm, a charge generating layer having a thickness of 0.3 μm and a charge transporting layer having a thickness of 18 μm were respectively formed to prepare an electrophotographic photosensitive member of the present invention.

Undercoat layer coating liquid Titanium dioxide 10 parts Polyester {Toyon Boshoku Co., Ltd. Byron 200} 1 part Toluylene-2,4-diisocyanate 0.1 part 2-Butanone 100 parts Methanol 60 parts Charge generation layer coating liquid 5 parts of charge generation material with the following structure

[0052]

[Chemical 5]

Polyvinyl butyral resin (UC-100 U-100) 2 parts Tetrahydrofuran 200 parts Charge transport layer coating liquid 8 parts charge transport material having the following structure

[0054]

[Chemical 6]

Polyarylate {Unitika U-100} 9 parts Tetrahydrofuran 100 parts Further, on the NESA glass substrate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample I-5) charge generation layer and charge transport layer After coating each of the stacks (Sample I-6) of
As a counter electrode, Al was vapor-deposited at about 500Å to prepare a sample.

Example I-4 On the same support as in Example I-3, a charge transport layer coating solution and a charge generating layer coating solution having the following compositions were sequentially applied and dried to give a 20 μm thick charge. A transport layer and a charge generation layer having a thickness of 0.5 μm were formed to prepare an electrophotographic photoreceptor of the present invention.

Charge Transport Layer Coating Solution 10 parts of charge generating substance having the following structure

[0058]

[Chemical 7]

Polycarbonate (GE company: Lexan-141) 10 parts Methylene chloride 90 parts Charge generation layer coating liquid 5 parts Charge transport material having the following structure

[0060]

[Chemical 8]

Polyester {Toyobo Co., Ltd .: Byron 300} 0.5 part Tetrahydrofuran 180 parts Further, on the Al plate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample I-7) and the charge generation layer and charge transport After coating each of the layer stacks (Sample I-8), Al was vapor-deposited at about 200Å as a counter electrode to prepare a sample.

Comparative Example I-1 The same procedure as in Example I-1 was carried out except that the charge generating material in Example I-1 was replaced with the material having the following structure.

Structural formula of charge generating substance

[0064]

[Chemical 9]

Comparative Example I-2 The same procedure as in Example I-1 was carried out except that the charge generating material in Example I-2 was changed to the material having the following structure.

Structural formula of charge generating material

[0067]

[Chemical 10]

Comparative Example I-3 The same procedure as in Example I-1 was carried out except that the charge generating material in Example I-3 was changed to the material having the following structure.

Structural formula of charge generating material

[0070]

[Chemical 11]

Comparative Example I-4 The same procedure as in Example I-1 was carried out except that the charge generating material in Example I-4 was changed to the material having the following structure.

Structural formula of charge generating substance

[0073]

[Chemical formula 12]

Samples I-1 to I-8 in Examples I-1 to I-4 correspond to samples I-9 to I-16 in Comparative Examples I-1 to I-4, respectively.

The characteristics of each photoconductor thus prepared were evaluated as follows using an electrostatic copying paper test apparatus (Kawaguchi Denki Seisakusho: SP-428 type).

First, corona discharge was performed for 15 seconds at a discharge voltage of 5.8 kV or -5.8 kV, and then dark decay was performed, and when the surface potential became -800 V or 800 V, 6 lux tungsten light was irradiated. ..

At this time, the surface potential V ₁₅ 15 seconds after the start of charging
(V), and the amount of exposure E ₄₀₀ (lux · s) required to bring the surface potential to −400 V or 400 V when irradiated with light.
ec) was measured.

Next, the conditions for measuring the fluorescence spectra of Samples I-1 to I-16 will be described.

Excitation light source: Ar ion laser (NEC)
488.1nm Detector: Ultra-high Sensitivity Instant Multimetering System IMUC-7
000 (Otsuka Electronics) was used.

The electric field strengths of the samples I-1 to I-4, I-
In 9 to I-12, 50 V / μm, sample I-
5 to I-8 and I-13 to I-16, 40 V /
The measurement was performed in μm (the sample caused dielectric breakdown at an electric field strength of 100 V / μm or more).

From the obtained fluorescence spectrum, (1)
Η was calculated using the formula.

At this time, the fluorescence intensity in the equation (1) is the fluorescence peak intensity of each charge generating substance.

The characteristics and η of the photoreceptor are shown in Table I-1.

[0084]

[Table 1]

Example II-1 A polyethylene terephthalate film vapor-deposited with aluminum was successively coated and dried with a coating solution for a charge generation layer and a coating solution for a charge transport layer having the following compositions, each having a thickness of 0.2 μm. Forming a generator layer and a 22 μm thick charge transport layer,
An electrophotographic photoreceptor of the present invention was produced.

Charge Generating Layer Coating Solution 5 parts of charge generating substance having the following structure

[0087]

[Chemical 13]

Polyvinyl butyral resin {Denki Kagaku Kogyo KK: Denkabutyral # 4000-1} 2 parts Cyclohexanone 250 parts 2-butanone 100 parts Charge transport layer coating liquid 8 parts charge transport material having the following structure

[0089]

[Chemical 14]

Polycarbonate {Teijin Kasei Co., Ltd .: Panlite L-1250} 10 parts Tetrahydrofuran 100 parts Further, on the non-fluorescent quartz glass substrate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample II-1), the charge. A sample was prepared by coating a laminate of the generation layer and the charge transport layer (Sample II-2).

Example II-2 An undercoat layer coating solution, a charge generating layer coating solution and a charge transport layer coating solution having the following compositions were applied and dried on the same support as in Example II-1 in this order. Undercoat layers of 0.3 μm each, and 0.
A 2 μm thick charge generation layer and a 22 μm thick charge transport layer were formed to prepare an electrophotographic photoreceptor of the present invention.

Undercoat layer coating solution 25% aqueous solution of water-soluble polyvinyl butyral {Sekisui Chemical Co., Ltd .: S-REC W-201} 50 parts Water 150 parts Methanol 200 parts Charge generating layer coating solution Charge generating substance having the following structure 4 Department

[0093]

[Chemical 15]

Cyclohexanone 100 parts 2-butanone 50 parts Charge transport layer coating liquid 9 parts Charge transport material having the following structure

[0095]

[Chemical 16]

Polycarbonate {Teijin Kasei Co., Ltd .: Panlite K-1300} 10 parts Methylene chloride 100 parts Further, on a non-fluorescent quartz glass substrate, only a charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample II-3), Samples were prepared by coating a stack of a charge generation layer and a charge transport layer (Sample II-4).

Example II-3 On a polyethylene terephthalate film provided with a Hastelloy conductive layer, a subbing layer coating liquid, a charge generating layer coating liquid and a charge transporting layer coating liquid having the following compositions were sequentially applied and dried. Then, an undercoating layer having a thickness of 2 μm, a charge generating layer having a thickness of 0.3 μm and a charge transporting layer having a thickness of 18 μm were respectively formed to prepare an electrophotographic photosensitive member of the present invention.

Undercoat layer coating liquid Titanium dioxide 10 parts Polyester {TOYOBO Co., Ltd. Byron 200} 1 part Toluylene-2,4-diisocyanate 0.2 parts 2-butanone 100 parts 4-Methyl-2-pentanone 70 parts Charge generation layer coating liquid 5 parts of charge generation substance with the following structure

[0099]

[Chemical 17]

Polyvinyl butyral resin (U-100 manufactured by UCC) 1 part Tetrahydrofuran 200 parts Charge transport layer coating liquid 7 parts Charge transport material having the following structure

[0101]

[Chemical 18]

Polyarylate {Unitika U-100} 9 parts Tetrahydrofuran 100 parts Further, on the non-fluorescent quartz glass substrate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample II-5), and the charge generation layer were used. Samples were prepared by coating the charge transport layer stacks (Sample II-6).

Example II-4 A charge transport layer coating solution having the following composition and a charge generating layer coating solution having the following compositions were successively applied and dried on the same support as in Example II-3 to obtain a charge having a thickness of 20 μm. A transport layer and a charge generation layer having a thickness of 0.5 μm were formed to prepare an electrophotographic photoreceptor of the present invention.

Charge Transport Layer Coating Liquid 10 parts of the charge generating substance having the following structure

[0105]

[Chemical 19]

Polycarbonate (GE company: Lexan-141) 10 parts Methylene chloride 90 parts Charge generation layer coating liquid 5 parts Charge transport material having the following structure

[0107]

[Chemical 20]

Polyester {Toyobo Co., Ltd .: Byron 300} 0.5 part Tetrahydrofuran 200 parts Further, on the non-fluorescent quartz glass substrate, only the charge generation layer having the same constitution as the above-mentioned photoreceptor (Sample II-7), charge generation. Layers and charge transport layers were laminated (Sample II-8) to form a sample.

Comparative Example II-1 The same procedure as in Example II-1 was carried out except that the charge generating material in Example II-1 was changed to the material having the following structure.

Structural formula of charge generation material

[0111]

[Chemical 21]

Comparative Example II-2 The same procedure as in Example II-1 was carried out except that the charge generating material in Example II-2 was changed to the material having the following structure.

Structural formula of charge generating material

[0114]

[Chemical formula 22]

Comparative Example II-3 The same procedure as in Example II-1 was carried out except that the charge generating material in Example II-3 was changed to the material having the following structure.

Structural formula of charge generating material

[0117]

[Chemical formula 23]

Comparative Example II-4 The same procedure as in Example II-1 was carried out except that the charge generating substance in Example II-4 was changed to the substance having the following structure.

Structural formula of charge generation material

[0120]

[Chemical formula 24]

Samples II-1 to II-8 in Examples II-1 to II-4 correspond to Samples II-9 to II-16 in Comparative Examples II-1 to II-4, respectively.

The characteristics of each photoconductor thus prepared were evaluated as follows using an electrostatic copying paper test apparatus (Kawaguchi Denki Seisakusho: SP-428 type).

First, corona discharge was carried out for 20 seconds at a discharge voltage of 6.0 kV or -6.0 kV, and then dark decay was carried out, and when the surface potential became -800 V or 800 V, 6.0 lux of tungsten light was emitted. Irradiated.

At this time, the surface potential V ₂₀ 15 seconds after the start of charging
(V), and the amount of exposure E ₄₀₀ (lux · s) required to bring the surface potential to −400 V or 400 V when irradiated with light.
ec) was measured.

Next, the conditions for measuring the fluorescence spectra of Samples II-1 to II-16 will be described.

Excitation light source: Ar ion laser (NEC)
488.1nm Detector: Ultra-high Sensitivity Instant Multimetering System IMUC-7
000 (Otsuka Electronics) was used.

From the obtained fluorescence spectrum, (1)
Η was calculated using the formula.

At this time, the fluorescence intensity in the equation (1) is the fluorescence peak intensity of each charge generating substance.

The characteristics and η of the photoreceptor are shown in Table II-1.

[0130]

[Table 2]

Example III-1 A polyethylene terephthalate film on which aluminum was vapor-deposited was coated with a photosensitive layer coating solution having the following composition and dried to form a photosensitive layer having a thickness of 22 μm. It was made.

Photosensitive layer coating liquid 0.6 part of charge generating substance having the following structure

[0133]

[Chemical 25]

10 parts of a charge transport material having the following structure

[0135]

[Chemical formula 26]

Polycarbonate {Teijin Kasei Co., Ltd .: Panlite L-1250} 10 parts Tetrahydrofuran 100 parts Further, on the non-fluorescent quartz glass substrate, the charge transport material was removed from the photosensitive layer of the above-mentioned photoreceptor (Sample III-1). ), And a photosensitive layer (Sample III-2) having the same structure as that of the above-mentioned photosensitive member was applied to prepare a sample.

Example III-2 On the same support as in Example III-1, an undercoat layer coating solution and a photosensitive layer coating solution having the following compositions were sequentially applied and dried to give a thickness of 0.3 μm. An undercoat layer and a photosensitive layer having a thickness of 20 μm were formed to prepare an electrophotographic photosensitive member of the present invention.

Undercoat layer coating liquid Water-soluble polyvinyl butyral 25% aqueous solution {Sekisui Chemical Co., Ltd .: S-REC W-201} 50 parts Water 100 parts Methanol 220 parts Photosensitive layer coating liquid Charge generating substance having the following structure: 8 copies

[0139]

[Chemical 27]

9 parts of charge transport material having the following structure

[0141]

[Chemical 28]

Polycarbonate {Teijin Kasei Co., Ltd .: Panlite K-1300} 10 parts Methylene chloride 100 parts Further, on the non-fluorescent quartz glass substrate, the charge transport material was removed from the photosensitive layer of the above-mentioned photoreceptor (Sample III- 3), a photosensitive layer (Sample III-4) having the same structure as that of the above-described photosensitive member was applied to prepare a sample.

Example III-3 On a polyethylene terephthalate film provided with a Hastelloy conductive layer, a subbing layer coating solution and a photosensitive layer coating solution having the following compositions were sequentially applied and dried to give a subbing layer having a thickness of 2 μm. Layer, a photosensitive layer having a thickness of 25 μm was formed to prepare an electrophotographic photosensitive member of the present invention.

Undercoat layer coating liquid Titanium dioxide 10 parts Polyester {Toyobo Co., Ltd. Byron 200} 1 part Toluylene-2,4-diisocyanate 0.2 parts 2-butanone 90 parts 4-Methyl-2-pentanone 80 parts Photosensitive layer coating liquid 0.7 parts of charge generating substance having the following structure

[0145]

[Chemical 29]

10 parts of charge transport material having the following structure

[0147]

[Chemical 30]

Polyarylate {Unitika U-100} 10 parts Tetrahydrofuran 100 parts Further, on the non-fluorescent quartz glass substrate, the charge transport material was removed from the photosensitive layer of the above photoreceptor (Sample III-5), the above. A photosensitive layer (Sample III-6) having the same structure as the photosensitive member was applied to prepare a sample.

Example III-4 On the same support as in Example III-3, a photosensitive layer coating solution having the following composition was applied and dried to form a photosensitive layer having a thickness of 20 μm. A photoconductor was prepared. Photosensitive layer coating solution 1 part charge generation material with the following structure

[0150]

[Chemical 31]

10 parts of a charge transport material having the following structure

[0152]

[Chemical 32]

Polycarbonate {GE Company: Lexan-141} 10 parts Methylene chloride 100 parts Further, on the non-fluorescent quartz glass substrate, the charge-transporting material was removed from the photosensitive layer of the above-mentioned photoreceptor (Sample III-7), the above-mentioned photosensitive material. A photosensitive layer (Sample III-8) having the same structure as the body was applied to prepare a sample.

Comparative Example III-1 Except that the charge generating substance in Example III-1 was changed to the substance having the following structure, the same procedure as in Example III-1 was carried out.

Structural formula of charge generation material

[0156]

[Chemical 33]

Comparative Example III-2 Except that the charge generating substance in Example III-2 was changed to the substance having the following structure, the same procedure as in Example III-1 was carried out.

Structural formula of charge generating material

[0159]

[Chemical 34]

Comparative Example III-3 Except that the charge generating substance in Example III-3 was changed to the substance having the following structure, the same preparation as in Example III-1 was carried out.

Structural formula of charge generating material

[0162]

[Chemical 35]

Comparative Example III-4 The same procedure as in Example III-1 was carried out except that the charge generating material in Example III-4 was replaced with the material having the following structure.

Structural formula of charge generating material

[0165]

[Chemical 36]

Samples III-1 to III-8 in Examples III-1 to III-4 correspond to samples III-9 to III-16 in Comparative Examples III-1 to III-4, respectively.

The characteristics of each photoconductor thus prepared were evaluated as follows using an electrostatic copying paper test apparatus (Kawaguchi Denki Seisakusho: SP-428 type).

First, corona discharge was performed for 20 seconds at a discharge voltage of 6.2 kV, and then dark decay was performed to reduce the surface potential to-.
4.5l at 800V or 800V
Irradiated with ux tungsten light.

At this time, the surface potential V ₂₀ 20 seconds after the start of charging
(V) In addition, the amount of exposure E ₄₀₀ (lux · sec) required for the surface potential to reach 400 V during light irradiation was measured.

Next, the fluorescence spectrum measurement conditions of Samples III-1 to III-16 will be described.

Excitation light source: Ar ion laser (NEC)
488.1nm Detector: Ultra-high Sensitivity Instant Multimetering System IMUC-7
000 (Otsuka Electronics) was used.

From the obtained fluorescence spectrum, (1)
Η was calculated using the formula.

At this time, the fluorescence intensity in the equation (1) is the fluorescence peak intensity of each charge generating substance.

The characteristics and η of the photoconductor are shown in Table III-1.

[0175]

[Table 3]

[0176]

As described above, according to the present invention,
It is possible to obtain a highly sensitive electrophotographic photosensitive member. Further, it is possible to obtain an electrophotographic photosensitive member having a small residual potential.

[Brief description of drawings]

[Figure 1]

2 is a schematic diagram of a cross section of a specific example corresponding to claims 1 to 3 of the present invention, FIG.

FIG. 3 is a schematic sectional view of a specific example corresponding to claim 3 of the present invention,

[Figure 4]

FIG. 5 is a schematic cross-sectional view of a specific example in which another layer is added to the basic structure of the present invention.

[Explanation of symbols]

 11 Conductive Support 13 Undercoat Layer 15 Photosensitive Layer 17 Protective Layer 21 Charge Generation Layer 23 Charge Transport Layer

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 16, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief explanation of the drawing

[Correction method] Change

[Correction content]

FIG. 1 is a schematic sectional view of a specific example corresponding to claims 1 to 3 of the present invention,

[Fig. 2] Same as above

FIG. 3 is a schematic cross-sectional view of a specific example corresponding to claim 4 of the present invention,

FIG. 4 is a schematic cross-sectional view of a specific example in which another layer is added to the basic structure of the present invention,

[FIG. 5] Same as above

Claims (5)

[Claims] 1. A laminated electrophotographic photosensitive member comprising a conductive support, and a charge generating layer containing at least a charge generating substance and a charge transporting layer containing a charge transporting substance, which are laminated at 100 V of the photosensitive member. / Μm or less, the fluorescence intensity ratio η represented by the following formula (1) is 0.9.
An electrophotographic photosensitive member characterized by the following: η = I _GT / I _G (1) However, η: Fluorescence intensity ratio I _G : Fluorescence intensity of charge generating material in a single layer of the charge generating layer in the photoconductor I _GT : Charge generating layer and charge in the photoconductor The fluorescence intensity of a charge generating substance when a transport layer is laminated is shown. 2. A laminated electrophotographic photosensitive member comprising a conductive support, and at least a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance laminated on the conductive support, without applying an external electric field. An electrophotographic photoreceptor having a fluorescence intensity ratio η represented by the following formula (1) of 0.9 or less measured in an electric field-free state. η = I _GT / I _G (1) However, η: Fluorescence intensity ratio I _G : Fluorescence intensity of charge generating material in a single layer of the charge generating layer in the photoconductor I _GT : Charge generating layer and charge in the photoconductor The fluorescence intensity of a charge generating substance when a transport layer is laminated is shown. 3. A laminated electrophotographic photosensitive member comprising a conductive support, and at least a charge generation layer containing a charge generation substance and a charge transport layer containing a charge transport substance, laminated on the conductive support, in a state where no internal electric field is applied. Measured in (1) below
An electrophotographic photoreceptor having a fluorescence intensity ratio η represented by the formula of 0.9 or less. η = I _GT / I _G (1) However, η: Fluorescence intensity ratio I _G : Fluorescence intensity of charge generating material in a single layer of the charge generating layer in the photoconductor I _GT : Charge generating layer and charge in the photoconductor The fluorescence intensity of a charge generating substance when a transport layer is laminated is shown. 4. A single-layer type electrophotographic photoreceptor containing at least a charge-generating substance and a charge-transporting substance on a conductive support, measured under the condition that an internal electric field is not applied, the following formula (1) of the photosensitive layer: An electrophotographic photoreceptor having a fluorescence intensity ratio η represented by η = I _GT / I _G (1) However, η: Fluorescence intensity ratio I _G : Fluorescence intensity of charge generating material in a single layer of the charge generating layer in the photoconductor I _GT : Charge generating layer and charge in the photoconductor The fluorescence intensity of the charge generating substance when a transport layer is laminated is shown. 5. The electrophotographic photosensitive member according to claim 1, wherein the charge generating substance is a disazo or trisazo pigment.