JPS6019149A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body low in surface friction coefft. and superior in resistances to abrasion, chemicals, humidity, etc. by laminating an electrostatic charge transfer layer contg. specified polysiloxane on a charge generating layer formed on a conductive substrate. CONSTITUTION:A charge transfer layer contg. a charge transfer substance, such as styryl type dye, and a binder resin, such as polycarbonate, is laminated on a charge generating layer contg. a charge generating substance, such as phthalocyanine, on a conductive substrate An intended electrophotographic sensitive body is obtained by incorporating in the material for constituting the charge transfer material, in an amt. of 10<-3>-5wt% of the total solid matters of said material, a polymer, such as methylphenylvinylpolysiloxane polymer, of a monomer unit represented by formula I or II in which R1 is <5C alkyl, and R2 is phenyl, vinyl, or the like.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a composite electrophotographic plate that is effective for creating an electrophotographic image, and in particular, the present invention relates to a composite electrophotographic plate that is effective for creating an image series by electrophotography, and is particularly concerned with durability (abrasion resistance) and resolution life. The present invention relates to a composite electrophotographic plate having layers.

[Background of the invention]

In electrophotographic copying, electrostatic recording, etc., a latent image by corona discharge, toner development, toner image transfer, and cleaning process of the transfer surface are repeated, so 1 ll of the surface of the electrophotographic plate is
l] It is required to have excellent abrasion and to have little change in electrophotographic characteristics over time.

Regarding wear resistance, protective layers and/or insulating layers such as /licon oil release layer, cellulose resin layer, vinyl resin layer, silicone resin layer, fluorine resin layer, etc. have been proposed. . However, these films are made to be as thin as possible in order not to impair the electrophotographic properties as much as possible, so they are susceptible to mechanical wear and damage, and are also susceptible to chemical deterioration in the corona electric field. Furthermore, image quality and other electrophotographic properties deteriorate, and satisfactory durability is not achieved. Furthermore, forming a protective layer or an insulating layer on the charge transport layer itself always involves problems of wear and interfacial peeling, and the more layers there are, the higher the cost becomes.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to provide a practical composite electrophotographic plate. By adding a specific boria xane to the charge transport layer itself without providing a protective layer or insulating layer, it lowers the surface friction coefficient and greatly improves wear resistance, as well as chemical resistance and Moisture and cleaning properties are also improved. Furthermore, it has been discovered that the image quality characteristics, particularly the M image resolution, are improved upon repeated use, leading to the present invention.

[Summary of the invention]

The present invention provides a composite electrophotographic plate in which a charge generation layer and a charge transport layer are laminated on a conductive support.
The defect is caused by the addition of polymeric substances having basic units represented by general formula [I] and CID, either singly or in combination, to a material comprising 1114 lt.

General formula [1] [In the formula, 1 is an alkyl group having 4 or more carbon atoms, and R2 is a phenyl group or a vinyl group. ] General formula [J] [In the formula, R1 represents an alkyl group having 4 or less carbon atoms, and R2 represents a phenyl group or a vinyl group. ] Composite electrophotographic plates consist of two layers, a charge generation layer and a charge transport layer, which is a unique structure, and the durability of the charge transport layer, which is the surface layer, determines the lifespan of the electrophotographic plate. is an important factor in determining

The charge transport layer is mainly composed of a charge transport device, a binder resin, and an additive, and the key point of the present invention is to add the above-mentioned specific boria as an additive.

The inventors' experiments on improving electrophotographic properties, improving durability such as abrasion resistance, and improving workability during layer formation using additives show that many polynoloxas/polymers are effective on surface lubricity such as abrasion resistance. However, many of them cause electrophotographic characteristics, particularly sensitivity reduction and residual potential increase. Among polylinoxanes, amino-modified, carboxyne-modified, epoxy-modified, epoxypolyether-modified, ester-modified, algide-modified, and styrene-modified boria xane etc. have a large decrease in sensitivity, and if used repeatedly as a photoreceptor, they will remain on the photoreceptor over time. Potential tends to increase. On the other hand, the poly/roxane described in the claims of the present invention improves the electrophotographic properties and the surface area by a factor of 11]. moreover,
The advantage is that the scientifically standardized 1tI; when coating a load carrying material on a conductive support, prevents scratches on the coated surface;
The leveling effect that smoothes the painted surface is also extremely effective.

The general formula [1] and/or [41] in the present invention
) The addition ratio I'i of poly-10xane is not particularly limited, but is o, o o i ~ 5 weight ratio, preferably 0.0 with respect to the total solid content constituting the charge transport layer.
1-2 weight 111% is used. When the amount added is less than this range, 1 anti-wear properties, 111 II chemical properties, side temperature properties,
Effects such as film formability are reduced. On the other hand, if the amount added exceeds this range, the adhesion at the interface with the charge generation layer tends to decrease, and the sensitivity of electrophotographic characteristics tends to decrease.

Next, as the styryl dye used in the present invention, a compound represented by the following formula is particularly desirable.

represents one type of hetero i group selected from and (however, Z represents O-1: or S, and the heterocyclic group may be substituted); R4 and R5 are alkyl groups having 3 or less carbon atoms.

As a substituent for such a heterocyclic group, -CI-1a
.

C21-I5, 'C3H7l which lower 7 /l/
Ki/l/ group, -ct.

Halogen groups such as -Rr, -N (CH3)2. N(
C2II5)z.

-N (C3H7)2 and other dialkylamino groups, -0
CI-13.

Examples include, but are not limited to, alkoxy groups such as -0C2H5 and phenyl groups. Some of these compounds are listed below based on their structural formulas.

The method for synthesizing the above compounds is described in detail in Japanese Patent Publications No. 35-11218, Japanese Patent Publication No. 35-11219, etc., and most of these compounds are manufactured by NK from Japan Photosensitive Color Research Institute Co., Ltd. It is commercially available as a dye.

The reason why the combination of a charge generating substance and a charge transporting substance as in this example is preferable is not clear, but known charge transporting substances such as pyrazoli/derivatives, hydrazone compounds, triphenyl meta/compounds, triphenylamine ,2,4.7
- Compared to dolinitrone-luorenone, etc., it has a relatively small ionization potential, is difficult to crystallize, is easy to blend with other binder resins, and can easily form a strong and uniform coating film. In particular, since it shows high sensitivity when negatively charged, it is expected that hole injection from the charge generating substance to the charge transporting substance is performed efficiently.

In addition to styryl dyes, charge transport q//J materials include bol)'-N-vinylcarbazole, poly-9, which exhibits photoconductivity.
- Polymers with nocarbazole or athracene groups such as p-vinylphenylanthracene in their side chains, other heterocycles such as pyrazoline rings and dibenizomofene, and polymers with aromatic rings in their chains. Molecules may be used in combination. It's a moat, but in history there are various types of dye bases, oxazole derivatives, oxadiazole derivatives, pyrazole derivatives, hydrazone compounds,
It is also possible to use known photoconductive low molecules such as nitrofluorenones such as poly-N-nitronefluorenone and mix them into a general-purpose resin to form a charge transport layer. Typical examples of oxazole derivatives include ( H, OC'H3).

These compounds can be effective by forming a charge transport layer by themselves, but in order to improve the strength, flexibility, adhesion, etc. of the coating film, they can be used in combination with other polymeric compounds. can be used to increase the effect.

The type of such polymer compound is not particularly limited, and may include known binder resins for electrophotographic plates, such as acrylic resins, polyester resins, Boristile 7 resins, epoxy resins, /recon resins, polycarbonate resins, and polyester carbonate resins. Phenol resins, urea resins, melamine resins, furano resins, urethane resins, cellulose derivatives, etc. are appropriately selected and used.

Phthalocyanine can be used as the charge generating substance in the present invention. Especially τ type, τ′ type, η type, η′
A metal-free phthalonanine such as a type is preferable.

τ-type gold metal phthalosoanine is defined as follows. That is, the Bragg angle (2θ±0, 2 degrees) is 7, i, 9.2
, 16.8.17.4. Strong against zo, 4 and 20.9
It has a line diffraction pattern. In particular, the infrared absorption spectrum is 751±2c between 700 and 760 cm.
The four absorption bands where the n-layer is strongest are 1320 to 1340.
Two absorption bands of approximately the same intensity between tlrI-' and 3
It is desirable to have a characteristic absorption of 288±3 or 1″.

τ′ type gold metal phthalocyanine is defined as follows.

That is, Cu K47 N 1! , for the X-rays of 541 people, the Bragg angle (2θ=l: o, 2 degrees) is 7.
5゜9.1, 16.8, 17.3, 20.3.20.8
This is a novel metal-free phthalonanine crystal polymorph having strong X-ray diffraction patterns of , 21.4 and 27.4. In particular, the four absorption bands in the infrared absorption spectrum between 700 and 760 twr-', which are strongest in summer, are 754-±2(1).
It is desirable to have two absorption bands of approximately the same intensity between 320 and 13'40 Cn+-' and a characteristic absorption at 32971:3m''''.

η-type phthalo7-anine is defined as follows. That is, 100 parts by weight of metal-free phthalocyanine, one type or a mixture of two or more types of metal-free phthalo/anine having a substituent on the benzene nucleus, a phthalocyanine nitrogen isoconstructor or metal phthalonanine which may have a substituent on the benzene nucleus. It is a mixture crystal with 50 parts by weight or less, and the infrared absorption spectrum is 753±1a+ between 700 and 760 cm-'.
-' is the strongest four absorption bands from 1320 to 134 Q
Two absorption bands of approximately the same intensity between cnn-s, 3
It has a characteristic absorption of 285±51771''.According to the inventor's study, the η-type gold metal phthalocyanine has a Bragg angle (26±0.2 degrees) of 7.6.
, 9.2°, which has an X-ray diffraction pattern showing strong peaks at 16.8, 17.4 and 28.5, and 7.6.9.2
．． Examples include those having an X-ray diffraction pattern showing strong peaks at 16.8°, 17.4, 21.5 and 275.

η′-type gold metal phthalo/anine is defined as follows.

That is, 100 parts by weight of metal-free phthalocyanine, one type or a mixture of two or more types of metal-free phthalonanine having a substituent on the benzene cedar, a phthalocyanine nitrogen isomer or metal phthalocyanine which may have a substituent on the benzene nucleus. It is a mixture crystal with 50 parts by weight or less, and has an infrared absorption spectrum of 700 to 7 (753±1 between 30 an-'
The four absorption bands with the strongest crn-” are 1320 to 13
32
It is a novel metal-free phthalonanine crystal polymorph with a characteristic absorption of 97±5ffi ''. According to the inventor's study, the Bragg angle (2θ±0.2 degrees) of the η' type gold metal phthalocyanine format is 7.5, 9.1, and 16.8 degrees.
Those with X-object diffraction patterns showing strong peaks at 7.3, 20.3, 26.8, 21.4 and 27.4, and those with 7.5
, 9.1, 16.8, 17. '3,20.3,20.8
It is desirable to have an X-ray diffraction pattern showing strong peaks at 21.4, 22.1, 27.4 and 285.

In addition, all metal-free phthalocyanines of τ type, τ' type, η type, and η' type have extreme values in the photosensitive wavelength range of 790 to 810.
It is in the 1 [11 box] of nm.

τ-type and τ'-type metal-free phthalocyanines that can be used in the present invention are produced in the following manner. That is, the α-type metal-free phthalo/anine is 50 to 180Us, preferably 60 to 130C.
The cloud form τ is obtained by milling with stirring or mechanical strain for a time sufficient to convert the crystals at a temperature of
A metal-free phthalonanine having a '-type crystal form is produced.

α-type phthalocyanine is a ``phthalo/anine compound'' by Moser and Humans (Moser 2nd Thomas
” Phthalocyanine Compoun
For example, metal-free phthalocyanine is a metal phthalocyanine that can be demetalized with an acid such as sulfuric acid, such as lithium phthalocyanine, sodium phthalocyanine, calcium phthalocyanine, etc. Those made directly from phthalodinitriles, aminoiminoisoindolenine or alcoquiniminoisoindolenine are still used by acid treatment of metal phthalocyanines, including phthalonanine, magnesium phthalonanine, etc. Metal-free phthalocyanine obtained by a well-known method is preferably dissolved in sulfuric acid at 5C or less, or made into a sulfate salt, and then poured into water or ice water to re-precipitate or hydrolyze it to obtain α-type metal-free phthalocyanine. 7-anine is obtained.

At this time, if an inorganic pigment dissolved or dispersed in sulfuric acid or a reprecipitation solution is used, an α-type metal-free phthalocyanine containing an inorganic pigment can be obtained. This inorganic pigment can be any water-insoluble powder that can be used as a hue filler, such as titanium white, zinc white, carbon, calcium carbonate, etc.
Examples include metal powder, alumina, iron oxide powder, and kaolin.

The α-type metal-free phthalocyanine containing this inorganic pigment is much easier to grind and can be easily made into fine particles when it is made into a pigment, and is effective in saving labor and energy.

The α-bery metal-free phthalocyanine treated in this way is
Although it is preferable to use it in a dry state, it is also possible to use a water paste. Dispersion media for stirring and kneading may be those commonly used for pigment dispersion, emulsification, and the like, such as glass beads, steel beads, alumina balls, and flint stones. However, a dispersion medium is not necessarily required. The grinding aid may be one that is normally used as a grinding aid for pigments, for example,
Examples include common salt, bicarbonate of soda, and vitreous salt. but,
This grinding aid is also not necessarily required.

If a solvent is required during stirring, kneading, or grinding, stirring,
It may be liquid at the temperature during kneading, such as alcoholic solvents, such as glycerin, ethylene glycol, diethylene glycol or polyethylene glycol bath agents, celonorb solvents such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, and ketone solvents. , ester ketone solvents, etc.

Typical equipment used in the crystal transition process is a general stirring equipment, such as a homomixer,
There are dispersers, agitators, stirrers or kneaders, Banbury mixers, ball mills, sand mills, attritors, etc.

The temperature range in the crystal transition step is 50 to 180C, preferably 60 to 130C. However, it is still effective to use crystal nuclei in the same way as in the normal crystal transition process.
Metal-free phthalo/anine with a W (IA group) in the α-type phthalonanine and benzene nucleus used in the production of mold metal metal phthalocyanine, even if the benzene nucleus has a substituent, it is more likely to be a phthalosoanine nitrogen isoconstructor or metal phthalocyanine. [Phthalonanine Compound J] by Maser and Thots, previously described
s ” PItLhalocyanine Compo
For example, α-type metal phthalones and other two compounds can be obtained by the same formulation as described above, and these include those containing voice pigments. Examples of phthalocyanine nitrogen isostructures include various porphines, such as copper tetrapyridinoporphyrazine in which one or more of the benzene nuclei of phthalocyanine is replaced with a quinoline nucleus, and metal phthalocyanines include , copper, nickel, cobalt,
Various materials such as zinc, tin, and aluminum can be mentioned.

Substituents include amine groups, nitro groups, alkyl groups, alkylene groups, nitro groups, mercapto groups, halogen atoms, and sulfonic acid groups, carboxylic acid groups or their metal salts, ammonium salts, amine salts, etc. can be exemplified as a relatively simple example. Furthermore, various substituents can be introduced to the benzene nucleus via alkylene groups, sulfonyl groups, carbonyl groups, imino groups, etc.
These are known as anti-aggregation agents or crystal conversion inhibitors in the technical field of phthalo/anine pigments (
For example, USI) 3973981, USI 40885
(see Publication No. 07), or unknown ones.

Known methods for introducing each substituent will be omitted.

In addition, things that are not publicly known are described as reference examples in the examples.

Mixing ratio of α-type metal-free phthalocyanine and metal-free phthalo/anine having a substituent on the benzene nucleus, or a phthalo-7anine nitrogen isomer or metal phthalocyanine that may have a substituent on the benzene nucleus: 1d100150 (weight ratio)
It may be above, but preferably 100/30 to 100
10.1 (weight ratio). Above this ratio, the obtained η
type and η' type aphthalonanine bleeds easily, reducing suitability as a pigment.

In order to mix in the above-mentioned proportions, they may be simply mixed, or may be mixed before the α-type metal phthalocyanine is subjected to base coating. The method for stirring or milling the mixture thus mixed may be the one normally used for dispersing, emulsifying, mixing, etc., and examples of dispersion media for stirring and kneading include glass beads, steel beads, alumina balls, etc. Flint is an example, but a dispersion medium is not necessarily required.

The grinding aid, the solvent during kneading, the row type and equipment used in the crystal transition step are the same as those for the τ type and τ' type gold metal phthalocyanine described above.

The temperature range in the crystal transition step of the η-type and η'-type metal phthalocyanine is 30 to 22 Orr, preferably 60 to 22 Orr.
Perform within a temperature range of 130C. At higher temperatures, it is easy to transition to the β-type, and at lower temperatures, it takes time to transition to the η-type and η'-type. It is also an effective method to use crystal nuclei as in the usual crystal transition process.

In addition to the above-mentioned τ-type, τ'-type, η-type, or η'-type metal-free phthalocyanine, the use of other charge-generating substances is also included. Examples of such a charge generating substance include α-type, β-type, R-type, or X-type gold-free maple phthalocyanine. Of course, the combined use of τ-type metal-free phthalonanine and η-type gold metal phthalocyanine is also effective. In addition, it is also effective to use phthalo/anine pigments other than those mentioned above, which are known as charge generating substances, such as phthalo/anine pigments, azo pigments, anthraquinone pigments, indigoid pigments, quinaclipane pigments, beryleno pigments, polycyclic quinono pigments, and methine squaric acid pigments. As an example of an azo pigment, (in the formula, X is OC mountain, and father is Ct), D (in the formula) M represents C+, Mg, or Ba. ) cheap monoazo pigments.

[Embodiments of the invention]

Example 1 1 part by weight of τ-phthalo-7-anine pigment (manufactured by Toyo Ink Co., Ltd.) and silicone resin (Shin-Etsu Chemical Co., Ltd., K'R, 52)
40) 3 parts by weight of the solution was made into 255 parts by weight with tetrahydro 7 run solvent, and dispersed and mixed for 2 hours using ultrasonic waves to obtain a charge generating substance, and this coating liquid was dip coated on aluminum foil with a film thickness of 100 μm. . Pulling speed during dip coating is 15mm
/sec. This was dried to form a charge generating material layer (charge generating layer). The thickness of this layer is approximately 0.7 μm.

Next, a charge transport substance having the following structural formula and a polycarbonate resin (Ondai Kasei: ■Gu1285) were used as a binder resin.
were mixed in a weight ratio of 1:3, methylene chloride/1,
1,2) A 100 parts by weight solution was prepared with lychlorethane/=6/4 (volume ratio). At this time, each coating liquid was obtained in which methylphenylboriaxane according to the present invention was added in an amount of 0 to 7% by weight based on the charge transport substance and the binder resin.

This coating solution was coated on the charge generating material layer by dip coating method and dried at 100C for 2 hours to obtain an electrophotographic plate.
The coating film thickness including all layers is 15 μm.

The electrophotographic properties of the composite type electrophotographic photoreceptor prepared from this Example 44rj were evaluated using a static +17' recording resistance tester (manufactured by Kawaguchi Electric Co., Ltd., 5P-428). In this case, conduct a negative 5 kV corona discharge for 10 seconds to charge the surface (surface potential immediately after charging for 10 seconds. (V) is the initial potential), leave it in a dark place for 30 seconds (at this time, change the potential to V2O ( V), (v3°/Vo)xloo(
%) as the darkening rate). Expose with a tungsten lamp so that 1 fading of the surface heat becomes 2 tUX, record the attenuation of the surface potential at this time and the time, and calculate the time t required for v3° to become 172. White light sensitivity (half exposure amount,
E5o(tux-8)).

At the same time, the surface was evaluated for external dirt and abrasion resistance. The 1i11i method for evaluating abrasion resistance is to ground the edge of a urethane blade with a thickness of 5 mm x width of 30 mm x length of 201 mm at an angle of 45 degrees to the surface of the electrophotographic plate, and apply 60 g of urethane blade to the surface of the electrophotographic plate. Surface wear was evaluated by applying a load and reciprocating for 60 strokes. The wear rate was expressed as the wear rate when running 50,000 times.

The results are shown in Table 1.

As a result, when the amount of methylphenylpolysiloxane added exceeds 5, the electrophotographic properties tended to deteriorate in initial potential, dark decay, and sensitivity. On the other hand, the higher the amount added, the better the results regarding wear resistance were obtained.

Example 2 To a charge generation layer obtained in the same manner as in Example 1, 1 part by weight of a charge transporting substance having the following structural formula, 3 parts by weight of a saturated polyester resin (manufactured by Toyobo Co., Ltd., Vylon 200) and 20 parts by weight of tetrahydrofuran were added. The coating liquid was dissolved, and in the same manner as in Example 1, methylphenylvinylboria xane was added to
A Seiko photographic plate was obtained by applying a coating liquid to which the weight was increased by 5 to 50% by weight.

The electrophotographic properties and abrasion resistance of these electrophotographic plates were investigated. The results are shown in Table 2.

Example 3 To a charge generation layer obtained in the same manner as in Example 1, 1 part by weight of a charge transporting substance having the following structural formula and 3 parts by weight of a polycarbonate resin (Lexan 141-111, manufactured by GE, USA) were added at 1.1.
2) Electrophotographic plates were obtained by coating 20 dishes with a coating solution in which lychloroethane was partially dissolved and methylphenylpolysiloxane was added in an amount of 0 to 5% by weight. The coating film thickness including all layers is 15 μm.

Example 1 Regarding the electrophotographic plate thus obtained
A repeated charge-exposure test was conducted using the electrostatic recording paper tester described above, and the image quality before and after the test was evaluated.

Charging-exposure conditions are negative charging 5kV, 10 seconds, dark decay 10
The exposure time was 5 seconds with a surface illuminance of 2 tux using a tungsten lung. This is 1000 cycles.
Cycle test was performed. For the electrophotographic plates before and after the test, a test chart AIR published by the Electrophotographic Society was developed by hand.

The resolution of 1975 was evaluated. The results are shown in the figure.

As a result, the resolution was better up to 2.0 inches compared to the one without the addition of methylphenylpolysiloxane, and the same result as the one without the addition of methylphenylpolysiloxane was obtained after three hits. If a certain resolution is important, 0.05 to 2.0% is optimal.

Note that τ′ type is used instead of τ type metal-free phthalocyanine.

Electrophotographic photoreceptors were obtained in the same manner as in Example 3 except that η-type and η'-type metal-free phthalonanine were used, and the electrophotographic properties of each were as good as in Example 3.

〔Effect of the invention〕

According to the present invention, an electrophotographic photoreceptor having excellent surface 1 abrasion resistance can be obtained.

[Brief explanation of the drawing]

The figure shows an electrophotographic photoreceptor 0/, according to an embodiment of the present invention.
0 2. Oty, θ 4. o, r,. Mechi'L7x = /L yK'ri, >akikari4sl
A amount cit%Continued from page 10 Inventor: Takano Stress Pressure Toyo Ink Mfg. Co., Ltd., 2-3-13 Kyobashi, Chuo-ku, Tokyo 0 Inventor: Manabu Sawada 2-3-13, Kyobashi, Chuo-ku, Tokyo Applicant within Toyo Ink Manufacturing Co., Ltd. Person: Toyo Ink Manufacturing Co., Ltd. 2-3-13 Kyobashi, Chuo-ku, Tokyo

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support, the carrier constituting the charge transport layer has the general formula [I] and [■]. ] A photoreceptor for electrophotography, characterized in that a polymeric substance having a basic unit represented by the following is added alone or in combination. General formula [I] [In the formula, ■ (l represents an alkyl group having 4 or less carbon atoms, R2 represents an alkyl group having 4 or less carbon atoms, a phenyl group, or a vinyl group.) [In the formula, ItI represents a carbon number of 4 or less an alkyl group, R2 represents a phenyl group or a vinyl group.] 2 In the charge transport layer, the general formula [I] and/or (
Claim 1, characterized in that the basic unit polymeric substance represented by n) is added in an amount of 10"3 to 5.0% by weight based on the total solid content of the material constituting the charge transport layer. 3. The charge transport substance in the charge transport layer is a styruryl dye and one type of heterocyclic group selected from the general formula (however, Z is 0 or S
and the heterocyclic group may be substituted), n represents 0, 1 or 2, and 4. ■t
5 represents an alkyl group having 3 or less carbon atoms. ) The electrophotographic photoreceptor according to claim 1, which is a compound represented by: 4. The charge generation substance in the charge generation layer is τ type, τ′ type, τ
4. The electrophotographic photoreceptor according to any one of claims 1 to 3, characterized in that it contains a metal phthalo/anine of type and/or η' type.