JPH0120419B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor in which a photosensitive layer comprising a combination of a carrier generation phase and a carrier transport phase is provided on a conductive support. To date, a carrier generation layer (hereinafter referred to as ``CGL'') containing a carrier generating substance (hereinafter referred to as ``CGM'') that absorbs visible light and generates a load carrier (hereinafter simply referred to as ``carrier''). )
and a carrier transport layer (hereinafter referred to as "CTL") containing a carrier transport material (hereinafter referred to as "CTM") that transports either or both of the positive and negative carriers generated in this CGL. It has been proposed that a photosensitive layer of an electrophotographic photoreceptor can be constructed by combining these materials. in this way,
By assigning the two basic functions necessary for the photosensitive layer, carrier generation and transport, to separate layers, the range of materials that can be used in the composition of the photosensitive layer is widened, and each function can be optimized. By doing so, it becomes possible to independently select materials or material systems that achieve the desired properties in the electrophotographic process, such as a high surface potential when charged, a large charge retention ability, and a high resistance to light. It becomes possible to construct an electrophotographic photoreceptor having excellent characteristics such as high sensitivity and great stability in repeated use. Conventionally, as such a photosensitive layer, the following ones are known, for example. (1) Consisting of amorphous selenium or cadmium sulfide
A structure in which CGL and CTL made of poly-N-vinylcarbazole are laminated. (2) Consisting of amorphous selenium or cadmium sulfide
A structure in which CGL and CTL containing 2,4,7-trinitro-9-fluorenone are laminated. (3) A structure in which a CGL made of a perylene derivative and a CTL containing an oxadiazole derivative are laminated (see US Pat. No. 3,871,882). (4) A structure in which a CGL made of chlordiane blue or methylscalyllium and a CTL containing a pyrazoline derivative are laminated (Japanese Patent Application Laid-Open No. 1973-
(See Publication No. 90827). (5) CGL made of amorphous selenium or its alloy;
A structure in which CTL containing a polyarylalkane-based aromatic amino compound is laminated (patent application)
52-147251). (6) A structure in which CGL containing a perylene derivative and CTL containing a polyarylalkane-based aromatic amino compound are laminated (Patent application 1973-
19907 specification). As described above, many types of photosensitive layers are known, but in conventional electrophotographic photoreceptors having such photosensitive layers, the electricity of the photosensitive layer when repeatedly subjected to electrophotographic processes is limited. It has the disadvantage of severe mechanical fatigue and a very short service life. For example, when the electrophotographic photoreceptor is repeatedly subjected to an electrophotographic process, the potential history state of the electrophotographic photoreceptor is not maintained stably, making it impossible to obtain stable image forming characteristics. Furthermore, the use of specific bisazo compounds as CGM is disclosed in, for example, JP-A-55-117151, JP-A-54-145142, etc.;
Even in combination with CTM, which is said to be able to be combined with CGM, the above-mentioned drawbacks are still considerable. As can be understood from this, a carrier transport substance that is effective against a specific carrier generating substance is not always effective against other carrier generating substances, and Nor can it be said that effective carrier generating substances are always effective against other carrier transport substances. If the combination of both substances is inappropriate, not only will the electrophotographic sensitivity become low, but also the discharge efficiency will be poor especially at low electric fields, so the so-called residual potential will increase.
In the worst case, potential accumulates each time it is used repeatedly, making it practically unusable for electrophotographic purposes. In this way, there is no legal way to select a suitable combination of the constituent substances of the carrier generation phase and the constituent substances of the carrier transport phase, and it is necessary to practically determine an advantageous combination from among many substance groups. . The present invention comprises a photosensitive layer consisting of a combination of a carrier generation phase and a carrier transport phase, has high sensitivity, and maintains a stable potential history state even when repeatedly subjected to an electrophotographic process. An object of the present invention is to provide an electrophotographic photoreceptor that can form good visible images. The above object is to provide an electrophotographic photoreceptor in which a photosensitive layer comprising a combination of a carrier generation phase and a carrier transport phase is provided on a conductive support, in which the carrier generation phase is a bisazo compound represented by the following general formula []. and the carrier transport phase is a styryl compound represented by the following general formula [] or an amine derivative represented by the general formula [] or the general formula []
This is achieved by an electrophotographic photoreceptor characterized by containing a styryl compound represented by the following formula and an amine derivative represented by the general formula []. General formula [] [In the formula, Ar ₁ , Ar ₂ and Ar ₃ are each a substituted or unsubstituted carbocyclic aromatic ring group or a substituted or unsubstituted heterocyclic aromatic ring group, R ₁ and R ₂ are each a cyano group or a halogen Electron-withdrawing group selected from atoms, A:

【formula】

【formula】

【formula】

[Formula] Also teeth

[Formula], X: hydroxy group,

[Formula] or −NHSO ₂ −R ₆ (where R ₄ and R ₅ are hydrogen atoms, substituted and
unsubstituted alkyl group, R ₆ is a substituted/unsubstituted alkyl group or a substituted/unsubstituted aryl group) Y: hydrogen atom, halogen atom, substituted/unsubstituted alkyl group, alkoxy group, carboxyl group, sulfo group, Substituted/unsubstituted carbamoyl group, substituted/unsubstituted carbamoyl group, or substituted/unsubstituted sulfamoyl group, Z: substituted/unsubstituted carbocyclic aromatic ring or substituted/unsubstituted heterocyclic aromatic ring Atom groups necessary for the composition, R ₃ : hydrogen atom, substituted/unsubstituted amino group, substituted/unsubstituted carbamoyl group or its ester group, A′: substituted/unsubstituted aryl group, n: 1 or 2 m: represents an integer of 0, 1 or 2. ) General formula [] [In the formula, R ₇ and R ₈ represent a substituted/unsubstituted alkyl group or phenyl group, and an alkyl group, an alkoxy group, or a phenyl group is used as the substituent. _R9 : substituted/unsubstituted phenyl group, naphthyl group,
It represents an anthryl group, a fluorenyl group, or a heterocyclic group, and an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, or a phenyl group is used as a substituent. _R10 : hydrogen atom, halogen atom, alkyl group,
Represents an alkoxy group or an alkylamino group. ] General formula [ ] [In the formula, Ar ₄ and Ar ₅ represent substituted/unsubstituted phenyl groups, and substituents include halogen atoms, alkyl groups,
A nitro group or an alkoxy group is used. Ar ₆ : Represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, fluorenyl group, or heterocyclic group, and substituents include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group,
An acyl group, an alkyl group, an aryl group, or an aralkyl group is used as a substituent for the aryl group, amino group, nitro group, piperidino group, morpholino group, naphthyl group, anthryl group, and substituted amino group. ] Among the bisazo compounds represented by the above general formula [], preferred are those represented by the following general formula [1a]. General formula [1a] [In the formula, Ar ₁ , Ar ₂ , Ar ₃ and A: the same as defined in the general formula [ ]. ] More preferred among the bisazo compounds represented by the above general formula [] are those represented by the following general formula [1b]. General formula [1b] [In the formula, A: the same as defined in the general formula [], Ar ₇ , Ar ₈ and Ar ₉ represent substituted or unsubstituted phenyl groups, and the substituents include alkyl groups such as methyl group and ethyl group. , alkoxy groups such as methoxy group and ethoxy group, halogen atoms such as chlorine atom and bromine atom, hydroxyl group and cyano group. ] That is, in the present invention, the bisazo compound represented by the above general formula [] is used as a CGM, and
A styryl compound represented by the above general formula [] or an amine derivative represented by the above general formula []
By combining these as CTM,
This constitutes a photosensitive layer of a so-called functionally separated type photoreceptor in which carrier generation and transport are performed using separate substances. As a result, it is possible to provide an electrophotographic photoreceptor that has high sensitivity, maintains a stable potential history state even when subjected to repeated electrophotographic processes, and can therefore always form good visible images. . Furthermore, in the electrophotographic photoreceptor of the present invention, a large spectral sensitivity can be obtained particularly in the long wavelength range of 600 to 700 nm, and therefore, for example, a helium-neon laser with a wavelength of 6328 Å can be used as a light source for forming a latent image. Furthermore, when the electric field is low, the so-called edge of the potential is well cut, and the potential of the non-image area becomes zero or close to zero during development, so it is impossible to obtain a large effective bias using a monocomponent developer made only of toner. It is also possible to perform good development. Specific examples of the bisazo compound represented by the general formula [] include those having the following structural formula, but are not limited thereto. Specific examples of the styryl compound represented by the general formula [] include those having the following structural formula, but are not limited thereto. Exemplary compound Specific examples of the amine derivative represented by the general formula [] include those having the following structural formula, but are not limited thereto. Exemplary compound Next, the mechanical structure of the electrophotographic photoreceptor of the present invention will be explained. In one example of the present invention, as shown in FIG. 1, a CGL 2 containing the above-mentioned bisazo compound as a main component is formed on a conductive support 1, and on this CGL 2, the above-mentioned styryl compound, The photosensitive layer 4 is formed by laminating CTL3 containing an amine derivative or a styryl compound and an amine derivative as main components, and these CGL2 and CTL3 form a photosensitive layer 4.
Configure. Here, as the material of the conductive support 1, for example, a sheet of metal such as aluminum, nickel, copper, zinc, palladium, silver, indium, tin, platinum, gold, stainless copper, or brass can be used. However, the invention is not limited to these. For example, as shown in FIG. 2, a conductive layer 1B may be provided on an insulating substrate 1A to constitute the conductive support 1. In this case, the substrate 1A may be Suitable materials include paper, plastic sheets, and other materials that are flexible and have sufficient strength against stress such as bending and tension. The conductive layer 1B can also be provided by laminating metal sheets, vacuum depositing metal, or by other methods. The above-mentioned CGL2 is produced by the above-mentioned bisazo compound,
Alternatively, it can be formed by adding a suitable binder resin to this, or by adding a substance having a high mobility to a specific or non-specific polar carrier, that is, CTM. As a specific method, a method is conveniently used in which the above-mentioned bisazo compound is dissolved or dispersed in an appropriate solvent or dissolved or dispersed together with an appropriate binder resin, and the mixture is coated on the support and dried. Ru. Here, as the solvent or dispersion medium,
n-butylamine, diethylamine, ethylenediamine, isopropanolamine, monoethanolamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone,
benzene, toluene, xylene, chloroform,
Examples of the binder resin include 1,2-dichloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, and dimethyl sulfoxide. Examples of the binder resin include polyethylene,
Addition polymerization resins and polyaddition resins such as polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, etc. , polycondensation type resins, and copolymer resins containing two or more of the repeating units of these resins, such as vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins In addition to insulating resins such as, polymeric organic semiconductors such as poly-N-vinylcarbazole can be mentioned. The ratio of this binder resin to the bisazo compound is from 0 to
100% by weight, especially in the range from 0 to 10% by weight. An appropriate CTM may be added to the CGL2 as necessary. The thickness of the CGL 2 formed as described above is preferably 0.005 to 20 microns, particularly preferably 0.05 to 5 microns. If it is less than 0.005 microns, sufficient photosensitivity cannot be obtained, and if it exceeds 20 microns, sufficient charge retention cannot be obtained. Further, the CTL 3 can be formed using the styryl compound described above in the same manner as the CGL 2 described above, that is, alone or together with a binder resin. Further, other CTMs may be included.
The thickness of this CTL 3 is between 2 and 100 microns, preferably between 5 and 30 microns. The electrophotographic photoreceptor of the present invention may have other mechanical configurations. For example, as shown in FIG. 3, a suitable intermediate layer 5 is provided on a conductive support 1, a CGL 2 is formed through this, and a CTL 3 is formed on this CGL 2.
may be formed. This intermediate layer 5 has a function of preventing free carriers from being injected from the conductive support 1 into the photosensitive layer 4 when the photosensitive layer 4 is charged, or a function of preventing the photosensitive layer 4 from being integrally connected to the conductive support. It can have a function as an adhesive layer for adhering to. Materials for the intermediate layer 5 include metal oxides such as aluminum oxide and indium oxide, acrylic resins, methacrylic resins, vinyl chloride resins, vinyl acetate resins, epoxy resins, polyurethane resins, phenolic resins, polyester resins, alkyd resins, Polymer materials such as polycarbonate resin, silicone resin, melamine resin, vinyl chloride-vinyl acetate copolymer resin, and vinyl chloride-vinyl acetate-maleic anhydride copolymer resin can be used. Further, as shown in FIG. 4, on the conductive support 1,
The photosensitive layer 4 may be constructed by forming the CTL 3 with or without the intermediate layer 5 and forming the CGL 2 on the CTL 3. Furthermore, it is also possible to form a single-layer photosensitive layer by dispersing the bisazo compound described above in a carrier transport phase containing the hydrazone derivative described above to form a carrier generation phase. In addition, various additives can be added to the layer constituting the photosensitive layer in the present invention, if necessary. Examples of the present invention will be described below, but the present invention is not limited thereto. Example 1 A conductive support made of polyethylene terephthalate with a thickness of 100 microns on which aluminum was vapor-deposited was coated with vinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslec MF-10" (manufactured by Sekisui Chemical Co., Ltd.). An intermediate layer with a thickness of approximately 0.05 microns was provided, and 1.5 g of the bisazo compound shown as Exemplified Compound (-9) was added to the
The resulting dispersion was coated on the intermediate layer using a doctor blade, and dried sufficiently to form a CGL with a thickness of about 0.5 microns.
was formed. On the other hand, 11.25 g of the styryl compound shown as exemplified compound (-32) and 15 g of polycarbonate resin "Panlite L1250" (manufactured by Teijin Kasei) were mixed with 1,2-
Dissolve in 100 ml of dichloroethane, apply the resulting solution onto the CGL using a doctor blade,
Dry thoroughly to form a 12 micron thick CTL.
An electrophotographic photoreceptor of the present invention was thus manufactured. This will be referred to as "Sample 1". Examples 2 to 4 In the formation of CGL-, exemplary compounds (-16), (-43) and (-
Example 1 except that each of those shown in 5) was used.
Three types of electrophotographic photoreceptors of the present invention were manufactured in exactly the same manner as described above. These are referred to as "Sample 2,""Sample3," and "Sample 4," respectively. Example 5 An electrophotographic photoreceptor of the present invention was produced in exactly the same manner as in Example 1, except that the styryl compound shown in Exemplified Compound (-21) was used as CTM in the formation of CTL. This will be referred to as "Sample 5." Examples 6 to 7 Electrophotographic photoreceptors of the present invention were produced in exactly the same manner as in Example 1, except that the amine derivatives shown in exemplified compounds (-8) and (-9) were used as CTMs in the formation of CTLs. did. These will be referred to as "Sample 6" and "Sample 7", respectively. Example 8 In the formation of CTL, exemplified compound (-18)
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1, except that 7.5 g of the styryl compound shown above and 7.5 g of the amine derivative shown as Exemplary Compound (-8) were used. This will be referred to as "Sample 8." Example 9 In the formation of CTL, exemplary compound (-22)
6 g of the styryl compound shown in and the exemplified compound (
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that 9 g of the amine derivative shown in -9) was used. This will be referred to as "Sample 9." Example 10 An intermediate layer was provided on a conductive support in the same manner as in Example 1, and 1.5 g of the bisazo compound shown as exemplified compound (-9) and 1.5 g of polycarbonate resin "Panlite L-1250" were mixed into 1 layer. , 2-dichloroethane (100 ml) and dispersed in a ball mill for 12 hours. The resulting dispersion was applied onto the intermediate layer using a doctor blade and sufficiently dried to form a CGL with a thickness of about 1 micron. . A CTL was formed on this CGL in the same manner as in the formation of CTL in Example 1, thereby producing an electrophotographic photoreceptor of the present invention. This will be referred to as "Sample 10." Comparative Example 1 A comparative electrophotographic photoreceptor was produced in the same manner as in Example 1, except that in the formation of CTL in Example 1, a pyrazoline derivative having the following structural formula was used instead of the styryl compound. This is referred to as "comparative sample 1." Comparative Example 2 A comparative electrophotographic photoreceptor was produced in the same manner as in Example 1, except that in the formation of CTL in Example 1, an oxadiazole derivative having the following structural formula was used instead of the styryl compound. This will be referred to as "comparative sample 2." For each of the electrophotographic photoreceptors obtained as described above, Samples 1 to 6, and Comparative Samples 1 to 3, an electrometer SP-428 type was used.
(manufactured by Kawaguchi Electric Seisakusho) to investigate its electrophotographic characteristics. In other words, the surface of the photoreceptor is charged with a voltage of -6KV.
The acceptance potential V _A (V) when charged for 5 seconds at 5
The potential V _I (initial potential) after dark decay for seconds is 1/2
The exposure amount E1/2 (lux・
seconds), and dark decay rate (V _A − V _I )/V _A ×100 (%)
I looked into it. The results are shown in Table 1.

【table】

[Table] From the results in Table 1, it is clear that the electrophotographic photoreceptor of the present invention has high sensitivity. In addition, each of Samples 1 to 10 and Comparative Samples 1 to 3 was transferred using a dry electronic copying machine "U-Bix2000R".
(manufactured by Konishiroku Photo Industry Co., Ltd.) for continuous copying, and the black paper potential Vb (V) at an exposure aperture value of 1.0.
and white paper potential Vm (V) using "Electrostatic Voltmeter Model 144D-1D" (manufactured by Monroe Electronics Inc.).
Measurement was made immediately before development. The results are shown in Table 2. The black paper potential here refers to the surface potential of the photoreceptor when the above-mentioned copying cycle is performed using black paper with a reflection density of 1.3 as an original, and the white paper potential represents the surface potential of the photoreceptor when a blank paper is used as an original. Represents electric potential.

[Table] As is clear from the results in Table 2, the electrophotographic photoreceptor of the present invention maintains a stable potential history state even when subjected to repeated electrophotographic processes.
A large number of visible images of good quality can be stably formed.

[Brief explanation of drawings]

FIG. 1 is an explanatory sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention, FIG. 2 is an explanatory sectional view showing another example of the structure of the electrophotographic photoreceptor of the invention, and FIGS. 3 and 4 2A and 2B are explanatory cross-sectional views showing still other structural examples of the electrophotographic photoreceptor of the present invention. 1... Conductive support, 2... Carrier generation layer (CGL), 3... Carrier transport layer (CTL), 4...
Photosensitive layer, 5... Intermediate layer, 1A... Insulating substrate, 1
B... Conductive layer.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor in which a photosensitive layer comprising a combination of a carrier generation phase and a carrier transport phase is provided on a conductive support, wherein the carrier generation phase is represented by the following general formula []. The carrier transport phase contains a styryl compound represented by the following general formula [], an amine derivative represented by the general formula [], or a styryl compound represented by the general formula [], and a styryl compound represented by the general formula []. An electrophotographic photoreceptor characterized by containing an amine derivative. General formula [] [In the formula, Ar ₁ , Ar ₂ and Ar ₃ are each a substituted or unsubstituted carbocyclic aromatic ring group or a substituted or unsubstituted heterocyclic aromatic ring group, R ₁ and R ₂ are each a cyano group or a halogen An electron-withdrawing group selected from atoms, A: [Formula] [Formula] [Formula] [Formula] or [Formula], X: hydroxy group, [Formula] or -NHSO ₂ -R ₆ (however, R ₄ and R ₅ are hydrogen atoms, substituted and
unsubstituted alkyl group, R ₆ is a substituted/unsubstituted alkyl group or a substituted/unsubstituted aryl group) Y: hydrogen atom, halogen atom, substituted/unsubstituted alkyl group, alkoxy group, carboxyl group, sulfo group, Substituted/unsubstituted carbamoyl group, substituted/unsubstituted carbamoyl group,
unsubstituted carbamoyl group or substituted/unsubstituted sulfamoyl group, Z: atomic group necessary to constitute a substituted/unsubstituted carbocyclic aromatic ring or substituted/unsubstituted heterocyclic aromatic ring, R ₃ : hydrogen atom, substituted/unsubstituted amino group, substituted/unsubstituted carbamoyl group or its ester group, A': substituted/unsubstituted aryl group, n: integer of 1 or 2, m: 0, 1 or 2 represents an integer. ) General formula [] [In the formula, R ₇ and R ₈ represent a substituted/unsubstituted alkyl group or phenyl group, and an alkyl group, an alkoxy group, or a phenyl group is used as the substituent. _R9 : substituted/unsubstituted phenyl group, naphthyl group,
It represents an anthryl group, a fluorenyl group, or a heterocyclic group, and an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, or a phenyl group is used as a substituent. _R10 : hydrogen atom, halogen atom, alkyl group,
Represents an alkoxy group or an alkylamino group. ] General formula [ ] [In the formula, Ar ₄ and Ar ₅ represent substituted/unsubstituted phenyl groups, and substituents include halogen atoms, alkyl groups,
A nitro group or an alkoxy group is used. Ar ₆ : Represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, fluorenyl group, or heterocyclic group, and substituents include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group,
An acyl group, an alkyl group, an aryl group, or an aralkyl group is used as a substituent for an aryl group, an amino group, a nitro group, a piperidino group, a morpholino group, a naphthyl group, an anthryl group, and a substituted amino group. ]