JPH0833661B2 - Photoconductive material - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductive material for an electrophotographic photosensitive member used in an electrophotographic copying machine, an optical printer or the like.

2. Description of the Related Art Photoconductive materials used in electrophotographic photoreceptors include Se organic semiconductors (hereinafter referred to as OPC) and amorphous silicon (hereinafter referred to as aS).
i: H). Each photoconductor has merits and demerits, and there is room for further improvement in characteristics. The present inventors have proposed the following electrophotographic photoconductors with high sensitivity and low cost.

(1) A function-separated photoreceptor in which a layer containing amorphous carbon as a main component is used as a charge transport layer and a charge generation layer is made of amorphous silicon.

This photosensitive member is made of a combination of amorphous silicon having a high quantum efficiency in a wide range over a long wavelength in the visible region and amorphous carbon which is a hard material and has a low dielectric constant. This is a combination of triple sensitivity and good printing durability.

However, the mobility of the amorphous carbon, which is the charge transport layer, is small and the carrier transport ability is limited. In terms of cost, there is a limit to cost reduction because the manufacturing method is the plasma CVD method.

(2) In a function-separated type electrophotographic photoreceptor having an organic material as a charge transport layer, the charge transport layer is a linear polymer having a phenylene group, and the substituent at the para-position of the phenylene group is a group having a conjugated bond, Alternatively, a photoreceptor containing at least one of groups containing a VIb group element. In order to improve the characteristics, oxygen doping by heat treatment in oxygen or doping by adding an oxidant is performed. Furthermore, the degree of polymerization is made uniform and optimized so that the orientation as a whole becomes the best.

This charge transport layer has firstly a high hole mobility, secondly it can be heat-sealed directly from the film to the substrate, and the film forming method is very easy. Thirdly, it is a thermosetting polymer. Therefore, it has the advantage of excellent printing durability. In particular, it has a high mobility and compensates for the drawbacks of the amorphous carbon, and it is considered that the improvement in the characteristics is due to the following reasons.

The movement of carriers in the bulk of a polymer is a result of intramolecular chain conduction and intermolecular chain conduction, and mobility is improved from both sides. The first guideline for improving conduction in the molecular chain is the expansion of molecular orbitals and the development of a conjugated system accompanying it, and charged solitons, bipolarons, polarons, etc. are considered as conduction mechanisms. To develop a conjugated system, it is necessary to have many π electrons in the main chain skeleton. It is also an effective means to bring a positive charge onto the main chain by exchanging charges with the electron acceptor. Further, it may have a structure in which electron orbits capable of hopping are adjacent to each other even if conjugation along the main chain is not developed.

The improvement of the second interchain conduction is classified into the improvement of crystallinity and the orientation. In any case, to facilitate transfer of the carrier to the adjacent polymer, the molecular chains are spatially densely arranged,
Moreover, it is necessary that the overlap of the electron trajectories in which the carriers move is large.

In a linear polymer having a phenylene group, the first improvement in intramolecular chain conduction can be developed centering on the π-electron system of the phenylene group. For example, by introducing a group having a conjugated bond between phenyl groups, the π-electron system is broadened. If there are VIb group elements in between,
The phenyl groups adjacent to each other in the straight chain have a twisted arrangement of π electron orbits, and the orbital spread in the straight line direction is small. However, the main chain tends to take a rigidly extended shape, and the crystallinity is significantly increased.
Therefore, the movement of carriers is mainly between adjacent electron orbits, and the conduction property between the second molecular chains is important for conduction.

The length of the molecular chain has a great effect on the crystallinity and orientation, and the crystallinity decreases due to the lengthening of the molecular chain, which in turn lowers the hopping probability of carriers and increases the probability of capturing carriers. Become. As the bulk of the molecular chain length, there is a length suitable for arranging the molecules most densely. By aligning the molecules to this length, it is possible to improve the second interchain conduction.

SUMMARY OF THE INVENTION A function-separated type photoreceptor in which a charge generation layer and a charge transport layer are composed of different layers and charge is exchanged through an interface is composed of materials suitable for charge generation and transport. By doing so, it is a promising method for obtaining a high-sensitivity photoconductor, but since the film structure is multi-layered, there is a problem in terms of cost. Further, carrier injection at the interface is a serious problem, and it is often difficult to obtain a good combination because it is difficult to inject even materials having high characteristics. It is a major issue to solve the problem of carrier injection through this interface.

Conventionally, as a photoreceptor having no interface, many photoreceptors having high sensitivity as a single body have been developed by incorporating a molecule having high charge transporting ability or a molecule having high charge generating ability into a polymer. However, in many cases, groups with high charge generation capability act as deep traps for carriers, which in turn hinders charge transport and disturbs the orientation of molecules that are essential for good carrier transport in the film. The characteristic was deteriorated.

On the other hand, in the case of a photoreceptor in which a charge transport material and a charge generation material are dispersed in the same layer, carrier generation and carrier transport in an amorphous state are performed except for a special case of forming a eutectic, and the combination of optimum materials is used. However, good results cannot be obtained. Further, the sensitivity can be improved simply by increasing the content ratio of the charge generating material, but in this case also, the charge transporting material acts as a carrier trap and the sensitivity is often lowered as a whole.

However, if the photosensitive layer is composed of a single layer, not to mention cost reduction, there are many advantages such as improvement of printing durability and uniformization of sensitivity distribution. Therefore, the present application focuses on the merit of forming a photosensitive layer with this single layer, and provides a photoconductive material that realizes a single-layer electrophotographic photoreceptor having both the charge generating function and the charge transporting function. It is intended.

Means for Solving the Problems As a photoconductive material that generates carriers by photoconductive photoexcitation of the present invention in order to achieve the above object, A material containing an organic molecule containing an aromatic ring having a group represented by X = O, S, Se, Te, Y = H, Cl, Br, I and n ≧ 0 is used.

Action When incorporating a charge transporting material and a sensitive group to be a charge generating material in the same molecule, the following points must be satisfied.

(1) The mobility of the charge transport material is high, and the charge easily transfers between molecules.

(2) It is a sensitive group having a high quantum efficiency of charge generation of the charge generation material and having sensitivity up to long wavelengths in the visible region.

(3) The incorporated functional group does not work as a carrier trap.

(4) The incorporated molecule has high crystallinity and high carrier transport ability.

First, it has been described in the above-mentioned prior art that a polymer containing a molecule including a phenylene group and a VIb group element has a high charge transporting ability. The carrier transport mechanism of this molecule is considered to be hopping conduction between adjacent phenylenes, and the transport direction is not limited to the main chain direction of the molecule, but rather the transfer direction between the molecular chains. In addition, the main chain of this molecule is apt to have a rigidly extended shape, and its crystallinity is extremely high.

Secondly, condensed polycyclic hydrocarbons such as anthracene, naphthalene, pyrene, perylene, naphthacene, benzoanthracene, benzophenanthrene, chrysene, triphenylene and phenanthrene as charge generating materials, anthraquinone, dibenzopyrenequinone, anthanthrone, isoviolanthrone. , Condensed polycyclic quinones such as pyranthrone, metal-free phthalocyanines, metal phthalocyanines containing metals such as copper, lead, nickel and aluminum, there are dyes such as indigo and thioindigo, which are each in the visible range, and light absorption in the vicinity thereof, Has a carrier generation area.

Thirdly, when the group consisting of the phenylene group and the VIb group element is joined to a sensitive group having a high charge generation ability, the carrier transport generated by the sensitive group moves in the molecule and passes through the path from the end to the next molecule. It is thought to go to the next molecule that is directly adjacent, rather than taking. Therefore, the problem of the carrier trap, which has conventionally been generated because the sensitivity group is always located on the path of the carrier traveling, is greatly improved. However, if the content ratio of the sensitive group is increased to increase the number of generated carriers, the problem of carrier trap still occurs. The content is controlled by the degree of polymerization of the phenylene group and the group consisting of VIb group elements.

In FIG. 4, the crystallinity varies depending on the above-mentioned degree of polymerization, and it is necessary to set the optimum degree of polymerization. The optimum value is determined as follows. When the degree of polymerization is increased, the rigidity of the molecule is increased, the crystal region is easily expanded, and the intermolecular carrier conduction is improved. The carrier trap density is low. On the contrary, when the degree of polymerization is lowered, the content of the sensitive group is relatively increased and the quantum efficiency of carrier generation is increased.

Example A photoconductive material according to an example of the present invention will be described below with reference to the drawings.

First, chemical formulas showing examples of organic molecules contained in the photoconductive material of the present invention are shown below. Condensed polycyclic hydrocarbons such as anthracene, naphthalene, pyrene, perylene, naphthacene, benzoanthracene, benzophenanthrene, chrysene, triphenylene, and phenanthrene, anthraquinone, dibenzopyrenequinone, anthanthrone, isoviolanthrone, pyranthrone, etc. In the case of using a condensed polycyclic quinone, a metal-free phthalocyanine, a metal phthalocyanine containing a metal such as copper, lead, nickel, or aluminum, indigo, or thioindigo.

FIG. 1 is a diagram schematically showing a cross section of an embodiment of an electrophotographic photosensitive member using a basic photoconductive material according to the present invention. In the electrophotographic photosensitive member shown in FIG. 1, a photoconductive layer 12 containing the above-mentioned organic molecules is formed on a support 11 made of an aluminum thin plate, and the upper surface of the photoconductive layer 12 is a free surface 13.
And The charge acceptor added to this photoconductive layer 12 is
I ₂ , Br ₂ , Cl ₂ , ICl, IBr, (NO ₂ ) BF ₄ , (NO ₂ ) PF ₆ , (N
_{O 2) SbF 6, HClO 4} , H 2 SO 4, HNO 3, HSO 4 -, AgClO 4, Fe (Cl
O ₄ ), BF ₃ , FeCl ₃ , FeBr ₃ , AlCl ₃ , InCl ₃ , InI ₃ , ZrC
l ₄ , HfCl ₄ , TeCl ₄ , TeBr ₄ , TeI ₄ , SnCl ₄ , SnI ₄ , SeC
_{l 4, TiCl 4, TiI 4} , FeCI 4 -, AlCI 4 -, AsF 5, SbF 5, NbC
l ₅ , NbF ₅ , TaCl ₅ , TaI ₅ , MoCl ₅ , ReF ₆ , IrCl ₆ , InF ₆ , U
_{F 6, OsF 6, XeF 6} , TeF 6, SF 6, SeF 6 ,, WF 6, WCl 6, ReF 7
Etc. As organic charge acceptors, tetracyanochidimethane (TCNQ), tetracyanoethane (TCNE), 2-
There is also 3, dichloro 5-6 dicyanobenzoquinone DDQ.

In addition, a barrier layer (not shown) may be provided between the support 11 and the photoconductive layer 12 in order to effectively block carriers injected from the support 11 into the photoconductive layer 12. For example, as a material for forming the barrier layer, Al ₂ O ₃ , BaO, BaO ₂ , BeO, Bi ₂ O ₃ , CaO, CeO
₂ , Ce ₂ O ₃ , La ₂ O ₃ , Dy ₂ O ₃ , Lu ₂ O ₃ , Cr ₂ O ₃ , CuO, Cu ₂ O, FeO,
PbO, MgO, SrO, Ta ₂ O ₃ , ThO ₂ , ZrO ₂ , HfO ₂ , TiO ₂ , TiO, Si
Metal oxides such as O ₂ , GeO ₂ , SiO, GeO or TiN, AlN, SnN, Nb
Metal nitride such as N, TaN, GaN, metal carbide such as WC, SnC, TiC or insulator such as SiC, SiN, GeC, GeN, BC, BN, heat resistance of polyimide, polyamide imide, polyacrylonitrile, etc. An organic compound having is used.

Further, a surface coating layer (not shown) may be formed on the free surface 13 in FIG. For example, suitable materials for the surface coating layer include Si _x O _1-x , Si _x C _1-x , Si _x N _1-x , and Ge _x O.
_1-x , Ge _x C _1-x , Ge _x N _1-x , B _x N _1-x , B _x C _1-x , Al _x N _1-x (0
<X <1) Inorganic substances such as carbon and layers containing hydrogen or halogen therein.

FIG. 2 is a sectional view schematically showing the construction of an electrophotographic photosensitive member of another embodiment of the present invention. The electrophotographic photosensitive member of the embodiment shown in FIG. 2 is different from that shown in FIG. 1 in that a charge transport layer 14 is further provided on the photoconductive layer 12 and the upper surface of the charge transport layer 14 is free. The point is surface 15.

Examples of the material forming the charge transport layer 14 include polyvinylcarbazole, triphenylamine derivatives, hydrazone derivatives, oxadiazole derivatives, indoline derivatives, polyparaphenylenevinylene, polyparaphenylene sulfide, and the like.

Example 1 Using the above-mentioned four kinds of condensed polycyclic hydrocarbons of naphthalene, anthracene, pyrene, and perylene as a sensitive group, VIb
Oxygen and sulfur were used as group elements. The structures of the organic compounds obtained as a result of the synthesis are the following eight types (a) to (d) and (f) to (d). For comparison, 1,
4-bis (phenylthio) benzene (ho) and 1,4-bis (phenoxy) benzene (nu) were also prepared.

Each organic compound was synthesized by the following method.

(B) 1,4-bis (phenylthio) naphthalene 2.5g of sodium hydride is added to the solvent NMP (N-methyl-2-pyrrolidinone) 40c.c., which is sufficiently water-free, and thiophenol 7c.c. is added dropwise. Then, the sodium salt of thiophenol was made. 1,4-dibromonaphthalene 2.9
g was added, and the mixture was heated to about 115 ° C. and stirred for about 3 hours. It was poured into 300 c.c. of water and the resulting precipitate was filtered. The precipitate was recrystallized from petroleum ether to obtain 1.8 g of compound crystals.

(B) 9,10-Bis (phenylthio) anthracene 1,4-Bis (phenylthio) naphthalene was prepared in the same manner as sodium salt of thiophenol, and 2.0 g of 9,10-dichloroanthracene was added to this solution and heated to about 90 ° C. And about 2
Stir for hours. After cooling, the reaction product insoluble in the solvent was filtered. This precipitate was recrystallized from benzene to obtain 2.2 g of crystals of the above compound.

(C) 1,6-Bis (phenylthio) pyrene Obtained by reacting a dihalide of pyrene with a sodium salt of thiophenol in the same manner as (i) and (b). 1,6-
Dichloropyrene is obtained by heating pyrene in carbon tetrachloride with sulfonium chloride to 75 ° C. 1,6-
The reaction between dichloropyrene and the sodium salt of thiophenol was carried out at 125 ° C. Recrystallization of the precipitate was obtained with benzene. From 2.0 g of dihalide, 1.4 g of the above compound was obtained.

(D) 3,9-Bis (phenylthio) perylene Similar to (c), a perchlorinated dichloro compound was synthesized and then reacted with sodium salt of thiophenol to heat perylene with aluminum chloride in nitrobenzene to 140 ℃. I got it. 1.2 g of the above compound was obtained from 3.0 g of the dihalide in the same manner as in (c) below.

(F) 1,4-bis (phenoxy) naphthalene 1,4-dibromonaphthalene 2.1 g and phenol 5.6 g potassium hydroxide 1.7 g copper powder 0.2 g are mixed and heated to 200 ° C. 3
Stir for hours. The mixed solution containing the reactants was poured into water to obtain a precipitate, which was recrystallized from ethanol.

(To) 9,10-bis (phenoxy) anthracene 9,10-dichloroanthracene 2.0 g and phenol 5.6 g,
1.7 g of potassium hydroxide and 0.2 g of copper powder were mixed, heated to 220 ° C. and stirred for 4 hours. The product obtained by further heating and stirring was poured into water to obtain a precipitate, which was then recrystallized from ethanol.

(H) 1,6-Bis (phenoxy) pyrene Using the 1,6-dichloropyrene obtained by the method of (C) above, the above compound was obtained by the same reaction as (E) and (F).

(I) 3,9-Bis (phenoxy) perylene The above compound was obtained by the same method using the 3,9-dichloroperylene obtained by the above-mentioned method (d).

In addition, 1,4-bis (phenylthio) benzene (ho) and 1,4-bis (phenoxy) benzene (nu) prepared for comparison were respectively obtained from paradichlorobenzene.

These 10 kinds of organic materials were thinned by vacuum evaporation method and their photoconductive properties were compared. Put 100 mg of each raw material powder in a quartz crucible and set it in a resistance heating type vacuum evaporation system, then set the crucible temperature to 300 at a vacuum degree of 2.0 × 1.0 ^-5 Torr or less.
Heated to ° C. The vapor deposition rate at this time was 5 to 20 Å / s. As the substrate, quartz glass was used for measuring photoconductive properties and optical properties, and high resistance Si was used for measuring infrared absorption spectra. Each film thickness was 5000Å. 3 (A) and 3 (B) have a phenylthio group as a substituent (a) to (d), and FIGS. 3 (C) and 3 (D) have a phenoxy group as a substituent (e).
The light absorption spectrum and the spectral sensitivity characteristic of the vapor deposition film of (H) are shown. For photocurrent measurement, a comb-shaped parallel electrode was formed on the sample surface with gold electrodes.

As is clear from FIG. 3, when the condensed polycyclic hydrocarbon is used as the sensitive group, the photocurrent maintains its magnitude as the number of rings increases and the wavelength range of light absorption shifts to longer wavelengths. The peak wavelength shifts while matching the peak wavelength of light absorption.

Example 2 An electrophotographic photosensitive member was manufactured according to the configuration of FIG. 2 in order to evaluate the above characteristics (a) to (h) as a charge generation layer of a function-separated type electrophotographic photosensitive member. That is, the degree of polymerization is 5 as a charge transport layer on a support such as an aluminum thin plate or a thin copper plate.
~ 20 para-phenylene sulfide (chemical formula At Z = S, n = 3 to 18) by a vacuum evaporation method.
~ 20 μm, and then (a) on this charge transport layer ~
The organic substance of (h) was formed as a charge generation layer in a thickness of 1 to 2 μm. These electrophotographic characteristics were evaluated under the conditions of initial charging potential of +600 V and halogen lamp light irradiation, and the results of comparison of the half exposure amount (E _1/2 ) and the residual potential (V _re ) are shown in Table 1.

Example 3 Using the sensitive groups anthracene and perylene, the influence of the degree of polymerization n of each substituent on photoconductivity was investigated. The method of synthesizing the synthesized compound is described below.

(A) Anthracene derivative Parachlorothiophenol 6.5c. In DMF (N, N-dimethylformamide) 100c.c.
c. and 2.5 g of sodium hydride were mixed to form a sodium salt of parachlorothiophenol. To this solution, 2.0 g of 9,10-dichloroanthracene was added, heated to 150 ° C. and stirred for 8 hours. This solution was poured into methanol to obtain a precipitate of the product, which was then separated into a benzene-soluble component and an insoluble component. Further, the benzene-soluble component was fractionally precipitated using hexane to separate it into two components. This reaction product is represented by the following chemical formula, and each precipitate has a different degree of polymerization n of the substituent. The degree of polymerization of these three types was estimated by the ratio of sulfur and chlorine contained in each molecule. As a result, on average 2
It was 3, 3-5, 5-10.

(B) Perylene derivative After the sodium salt of parachlorothiophenol was prepared in the same manner as in (a), the dichloro compound 3,9-dichloroperylene (b1) and the tetrachloro compound 3,4,9,10- Tetrachloroperylene (b2) was added respectively. 3,4,9,
The synthesis of 10-tetrachloroperylene was performed in a mixed solvent of glacial acetic acid.
It was carried out by chlorination with concentrated hydrochloric acid and hydrogen peroxide at ℃. DM
After heating to 150 ° C. in a solvent F and stirring for 8 hours, the mixture was poured into methanol to obtain a precipitate, which was then separated into a benzene-soluble component and an insoluble component. (A) Similarly, it was estimated by the ratio of sulfur and chlorine contained in each precipitate. As a result, 2 to 4 and 4 to 8 from the dichlorinated compound and 1 from the tetrachlorinated compound.
-3, 3-5 product (b1, b2) was obtained.

(C) Pyrene derivative (a) and (b) After the sodium salt of parachlorothiophenol was prepared similarly, 1,6-dichloropyrene which is a dichloro compound and 1,3,6,8- which is a tetrachloro compound. Tetrachloropyrene, an octachloro compound 1,3,4,5,6,8,
9,10-Octachloropyrene was added respectively. Where 1,
The synthesis of 3,6,8-tetrachloropyrene can be obtained by heating pyrene and sulfonium chloride in a nitrobenzene solvent. Also 1,3,4,5,6,8,9,10-octachloropyrene can be obtained by heating pyrene and sulfonium chloride in the same nitrobenzene solvent. Similarly, these were heated in DMF solvent at 150 ° C., stirred for 8 hours, added to methanol to obtain a precipitate, and then classified into a component soluble in benzene and an insoluble component. As a result of similar estimation of the degree of polymerization, almost the same two kinds of synthetic compounds (C1, C2, C3) of 1 to 3 and 3 to 5 were obtained from dichloropyrene, tetrachloropyrene and octachloropyrene, respectively.

In order to examine the photoconductivity of these 13 kinds of organic substances, thin films were formed by the vacuum deposition method as in Example 1. Film thickness is 15 μm
It vapor-deposited in several times so that it might become. The electrophotographic properties of these films are shown in Table 2.

As is clear from Table 2, the properties of each derivative increase as the degree of polymerization of the phenylthio group as a substituent increases. On the other hand, as can be seen from the case of the pyrene derivative in which the substituent substituting the sensitive group changes, the photosensitivity of the derivative having 2, 4 or 8 substituents increases with the increase in the number of the substituents. Is good, but 8 is poor.

Anthracene derivative (a) and perylene derivative (b1)
The same photocurrent measurement as in Example 1 on quartz glass.
The test was performed on a sample having a film thickness of 5000A. Results are shown in FIG. As is clear from the characteristic diagram of FIG. 4, the photocurrent is remarkably increased by increasing the degree of polymerization of both derivatives.

Example 4 An organic substance having a phenylthio group as a substituent was synthesized by using each of condensed polycyclic quinone dyes, phthalocyanine dyes, and indigo dyes as sensitive groups. The chemical formulas of the synthesized organic substances are shown below. From the condensed polycyclic quinone as the sensitive group, there are three types of anthraquinone (d1), anthanthrone (d2) and pyrantrone (d3), and from phthalocyanine, two types of metal-free phthalocyanine (e1) and copper phthalocyanine (e2), and indigo. The two types were indigo (f1) and thioindigo (f2).

The synthesis of each organic substance was performed as follows.

Prepare a dihalide of each sensitive group. Three types of condensed polycyclic quinone type were brominated respectively, phthalocyanine type was similarly chlorinated, and indigo type was brominated. These dihalides were mixed with the sodium salt of parachlorothiophenol in DMF solvent. The precipitate obtained as a result of this reaction was thoroughly washed with water, then washed with ethanol and dried.

These seven types of photoconductive materials are used as the charge generation layer and have the chemical formula Among the organic molecules represented by Z = 0, S, Se, Te, n ≧ 3, polyparaphenylene sulfide (hereinafter referred to as PPS) and polyparaphenylene vinylene (hereinafter referred to as PPV) having a degree of polymerization of 5 to 100. (Referred to as “2”) as a charge transport layer
A function-separated electrophotographic photoreceptor having the structure shown in the figure was produced.

Hawkins method (Mac)
romole.9 (1976) 189) and a film thickness of 20 μm was formed from this PPS raw material powder by a vacuum evaporation method. The synthesis of PPV was carried out by thermal polymerization of poly (xylylene-α-diethylsulfonium bromide), which is one of the polymeric sulfonium salts. The heat treatment conditions are nitrogen gas.
It was set to 200 to 400 ° C. and 1 to 10 hours. As with PPS, a film thickness of 20 μm was formed by the vacuum evaporation method. On the charge-transporting layer, the above-mentioned seven kinds of photoconductive materials were formed into a film having a thickness of 1 μm as a charge-generating layer also by a vacuum evaporation method.

 Table 3 shows the characteristics of these electrophotographic photoreceptors.

Example 5 Dispersion of the perylene derivative in Example 3 into another organic molecule was examined. The organic molecule that is the base of the dispersion has a chemical formula Degree of polymerization 5 to 2 in Example 4 satisfying Z = O, S, Se, Te, n ≧ 3
A PPS of 0 was used. Dispersion film formation is perylene derivative and PPS
Was performed by simultaneous vacuum evaporation of two sources, and the dispersion ratio was controlled by the ratio of two evaporation rates. Table 4 shows the results of electrophotographic characteristics of these dispersion type photoreceptors. In Table 4, d ₁ (A / S) is the perylene derivative, d ₂ (A / S) is the deposition rate of PPS, and the dispersion ratio was varied between 1/4 and 3/4.

Example 6 The pyrene derivative in Example 3 (n = 1 to 3, 3 to
5) was mixed with an electron acceptor as an additive, and its effect was examined. TCNQ (7,7,8,8, tetracyanoquinodimethane) was used as an additive. 20μ on the substrate by the method of Example 3
After the film formation, this substrate was placed in a heatable vacuum device, and the above-mentioned additive TCNQ was introduced in a gas state and mixed by diffusion into the film. The substrate was heated to approximately 150 ℃ to efficiently promote the diffusion of TCNQ in the film and the formation of the charge transfer complex. As a result of evaluating the characteristics of the photoconductor thus prepared, it was found that E _1/2 = 81 _xsec , V res for the sample of thioindigo (n = 1 to 3).
= 18v becomes E _1/2 = 6.41x _sec , V res = 12v, and E _1/2 = 41 _xsec , V res = 1 in the thioindigo (n = 3-5) sample.
Good characteristics were obtained with 4 v E _1/2 = 3.11 _xsec and V res10v.

Effects of the Invention When the photoconductive layer that generates carriers by photoexcitation is the organic material of the present invention, the carriers are efficiently generated when irradiated with light having a wide light wavelength from the visible region to the long wavelength. The generated carriers can easily move in the material by an external electric field. When this material is used as an electrophotographic photosensitive member, the most suitable aromatic ring having an optical absorption range from a short wavelength to a long wavelength in the visible region can be used as a sensitive group according to the wavelength of a light source. , Which has good sensitivity to a light source in a wide wavelength range. Therefore, it becomes possible to provide a photoconductive material in which a group having a high charge generating ability and a group having a high transporting ability are bound without impairing the ability.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of one embodiment of a basic electrophotographic photosensitive member using the photoconductive material of the present invention, and FIG. 2 is a schematic sectional view of another embodiment of the same electrophotographic photosensitive member. FIG. 3 is a characteristic diagram showing the light absorption and photocurrent spectral sensitivity characteristics of a vapor deposition film having a phenylthio group and a phenoxy group as substituents, and FIG. 4 is the photocurrent spectral sensitivity of the electrophotographic photosensitive member of Example 3. It is a characteristic view which shows a characteristic. 11 ... Support, 12 ... Photoconductive layer, 14 ... Charge transport layer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koji Akiyama 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masanori Watanabe 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 56) References JP-A-55-90954 (JP, A) JP-A-60-59353 (JP, A)

Claims (6)

[Claims] 1. In a photoconductive material containing an organic molecule that generates a carrier by photoexcitation, an organic molecule having a condensed polycyclic hydrocarbon, a condensed polycyclic quinone, a metal phthalocyanine, or indigo or thioindigo is represented by the following chemical formula. A photoconductive material having one or more of the following groups. 2. A group represented by the above chemical formula in the same molecule.
The photoconductive material according to claim 1, comprising from 4 to 4. 3. A group represented by the above chemical formula in the same molecule.
X of at least 2 groups are the same VIb
The photoconductive material according to claim 1, wherein the photoconductive material is a group element. 4. The photoconductive material according to claim 1, wherein an electron acceptor is added to the photoconductive material containing the organic molecule according to claim 1. 5. A photoconductive material that generates carriers by photoexcitation is composed of two or more layers made of different materials, at least one layer of which is composed of the photoconductive material of claim (1) and another layer. A photoconductive material, wherein one layer includes a layer containing an organic molecule represented by the following chemical formula. 6. A photoconductive material comprising the photoconductive material according to claim 1, which generates carriers upon photoexcitation, dispersed in the organic molecule represented by the above chemical formula.