JPS6017449A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body superior in sensitivity, durability, etc., and capable of always forming a good image by forming a photosensitive layer made of a combination of a carrier generating phase contg. a specified bisazo compd. and a carrier transfer phase contg. a pyrazoline compd. CONSTITUTION:A photosensitive body is obtained by forming on a substrate a combination of (1) a carrier generation phase contg. a bisazo compd., e.g., formula IV, represented by formula I in which Ar<1>, Ar<2> are each an aromatic C ring group or heterocyclic group; R<1>, R<2> are each an electron attractive group or H; A is formula II, III or the like; X is OH or the like; Y is H, halogen, or the like; Z is an atomic group necessary to constitute an aromatic carbon or hetero ring; (m) is 0-4; and (n) is 1 or 2, and (2) on this phase a carrier transfer phase contg. a pyrazoline compd., e.g., formula VI, represented by formula V in which R<7>-R<9> are each aryl; R<10>, R<11> are each H, 1-4C alkyl, aryl, or the like; and (l) is 0 or 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor, such as an electrophotographic photoreceptor, having a photosensitive layer serving as a carrier generation phase and a carrier transport phase.

2. Prior Art According to a conventionally known electrophotographic photoreceptor, a carrier-generating substance (hereinafter referred to as rCGMJ) that absorbs visible light and generates charge carriers (hereinafter simply referred to as "carrier") is used.
There is a thing. ) containing a carrier generation layer (
Hereinafter, it may be referred to as r CG L J. ) and a carrier transport substance (hereinafter referred to as rcT) that transports either or both of the positive and negative carriers generated in this CGL.
There is a thing called MJ. ) and a carrier transport layer (hereinafter sometimes referred to as rcTLi) to form a photosensitive layer. in this way,
By assigning the two necessary basic functions of carrier generation and carrier transport to separate layers constituting the photosensitive layer, the range of materials that can be used in the composition of the photosensitive layer is widened, and each It becomes possible to independently select a material or material system that optimally performs the function. In addition, this provides excellent characteristics required in the electrophotographic process, such as high surface potential when charged, high charge retention capacity, high photosensitivity, and high stability over repeated use. It becomes possible to obtain an electrophotographic photoreceptor having such characteristics.

As the above-mentioned photosensitive layer, for example, the following ones are known.

fl), CG consisting of amorphous selenium or cadmium sulfide
A structure in which L and CTL made of poly-N-vinylcarbazole are laminated.

(2) CG made of amorphous selenium or cadmium sulfide
A structure in which L and CTL containing 2,4.7-1-dinitro-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 the specification of US Pat. No. 3,871,882).

(4) CGL consisting of chlordian blue or methylscalyllium and CTL containing a pyrazoline derivative
(Refer to Japanese Unexamined Patent Publication No. 51-90827).

(5) A structure in which a CGT made of amorphous selenium or its alloy is laminated with a CTL containing a polyarylalkane-based aromatic amino compound (Patent Application No. 52-147)
251 Specification).

(6) A structure in which a CGL containing a perylene derivative and a CTL containing a polyarylalkane aromatic amino compound are laminated (Japanese Patent Application No. 19907/1983 W
).

Although many types of functionally separated photosensitive layers are known, in conventional electrophotographic photoreceptors having such photosensitive layers, the photosensitive layer changes when subjected to repeated electrophotographic processes. It has the disadvantage of severe electrical fatigue and a very short service life.

For example, when subjected to repeated electrophotographic processes,
The potential history state of the electrophotographic photoreceptor is not maintained stably,
Stable image forming characteristics cannot be obtained.

Further, the use of specific bisazo compounds as CGM is disclosed in, for example, JP-A-55-117151 and JP-A-54.
Although it is disclosed in Publication No.-145142, etc.
Even in the combination with CTM, which is said to be able to be combined with M, the above-mentioned drawbacks are still considerable.

As can be understood from this, a carrier transporting substance that is effective for a specific carrier-generating substance is not necessarily effective for other carrier-generating substances, and It cannot be said that a carrier generating substance that is effective against transport substances is also effective against other carrier transport substances. If the combination of these two materials 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, and in the worst case, repeated use will cause damage. Potential accumulates in the area, making it practically unusable for electrophotographic purposes.

In this way, it is thought that there is no lawful selection method for a suitable combination of the constituent substances of the carrier generation phase and the constituent substances of the carrier transport layer, and it is necessary to practically select an advantageous combination from among many substance groups. Need to decide.

On the other hand, in a photoreceptor using poly-N-vinylcarbazole as the CTM, for example, as in (1) above, the film is hard because poly-N-vinylcarbazole lacks malleability. It has the drawbacks of being brittle, prone to cracking and peeling, and poor durability. Therefore, when plasticizers are added to increase flexibility, the residual potential increases, causing fog in the image, etc. This had the disadvantage that the characteristics deteriorated.

In addition, using a low molecular weight organic compound as a charge transport material,
Efforts have been made to obtain electrophotographic photoreceptors having excellent electrophotographic properties and film strength by using a desired charge-generating substance in combination with a polymeric binder. However, as a low molecular weight charge transport material, for example, 2.5-
Bis(p-diethylaminophenyl)-1,3,4-
Oxadiazole derivatives such as oxadiazole have been selected and used as preferred materials, but these have poor compatibility with polymeric binders, and as a result, are likely to be sold out (and have poor thermal stability). There are drawbacks.

Further, the technology of using a pyrazoline compound as a photoconductive material in an electrophotographic photoreceptor is disclosed in, for example, US Pat.
! L, No. 729 and is well known, but it is used as a material that absorbs light to generate charges and transports charges, and is not used as a charge transport material responsible only for charge transport. It's not what is being said.

Furthermore, the technique of using a pyrazoline compound as a charge transport material is described in, for example, U.S. Pat. The pyrazoline compound has poor compatibility with the polymeric binder added to improve the physical properties, and when the amount of polymeric binder necessary to obtain the desired physical properties is used, the pyrazoline compound thermally crystallizes, and as a result, the charge The transport layer becomes turbid, resulting in a decrease in light transmittance and, in turn, a decrease in the sensitivity of the photoreceptor.

Further, a charge transport layer which causes turbidity as described above generally has poor layer uniformity and storage stability, and also tends to have poor charging characteristics. The reality is that a practically preferable charge transport material has not been found for producing electrophotographic photoreceptors.

3. Purpose of the Invention An object of the present invention is to have a photosensitive layer consisting of a combination of a carrier generation phase and a carrier transport layer, to exhibit high sensitivity, and to provide high sensitivity even when repeatedly used in an electrophotographic process, etc. It is an object of the present invention to provide a photoreceptor in which a potential history state is maintained stably and a good visible image can be formed at all times.

Another object of the present invention is to provide a photoreceptor having a charge transport layer with improved film strength, uniformity, and stability by using a charge transport material with excellent compatibility with a polymeric binder. be.

4. Structure of the invention and its effects, that is, the present invention provides a photoreceptor having a photosensitive layer consisting of a carrier generation phase and a carrier transport layer, in which the carrier generation phase comprises a bisazo compound represented by the following general formula (1). and the carrier transport layer contains a pyrazoline compound represented by the following general formula (II).

General formula [I]: A-N=N-Ar'-C=C-Δr2-N=N-A1
1゜IR2 [However, in this general formula, Ar' and Ar2: each substituted or unsubstituted carbocyclic aromatic ring group, or substituted or unsubstituted heterocyclic aromatic ring group, R1 and R2: each electron Attractive group or hydrogen atom (
(17J, at least one of R2 is an electron-withdrawing group), A: or -NH3O2-R6, provided that R4 and R5 are each a hydrogen atom, a substituted or unsubstituted alkyl group, and R6 is a substituted or unsubstituted Alkyl group or substituted or device-substituted aryl group> Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carbogyyl group, a sulfo group, a substituted or unsubstituted carbamoyl group, or a substituted or unsubstituted carbamoyl group. Sulfamoyl group (However, when rn is 2 or more, groups may be different from each other.) Z represents a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring. Atom group necessary for the composition, 'R3 is a hydrogen atom, a substituted or unsubstituted amino group,
a substituted or unsubstituted carbamoyl group, a carboxyl group or a nistyl group thereof; A is a substituted or unsubstituted aryl group; n is an integer of 1 or 2; m is an integer of 0 to 4. )] General formula (■): R 1 R7-C-C-H 1 [However, in this general formula, j2:0 or 1, R7, R8 and RB, substituted or unsubstituted aryl group, O R and R : A hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group or aralkyl group (However, R and R are not necessarily both hydrogen atoms, and when β is 0, R is hydrogen. Note that the above-mentioned "phase" used in the present invention includes not only a so-called layered structure but also a phased structure in which the constituent substances are in contact with each other.

According to the present invention, the bisazo compound represented by the general formula [1] is used as a CGM, and the bisazo compound represented by the general formula [If
) using the pyrazoline compound shown as C-M,
By skillfully combining these materials, the photosensitive layer of a so-called functionally separated photoreceptor is constructed, in which carrier generation and transport are performed using separate substances. This makes it possible to create a 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 photoreceptor of the present invention, a large spectral sensitivity can be obtained especially in the long wavelength range of 600 to 7QQnm, and therefore, for example, a helium-neon laser with a wavelength of 6328 nm can be used as a light source for forming a latent image. ,
Furthermore, when the electric field is low, the IJ potential is well cut off, and the potential of the non-image area becomes zero or close to zero during development. It is also possible to perform good development.

Further, the pyrazoline compound represented by the general formula (II) according to the present invention has poor compatibility with various polymeric binders, and even if the amount of the pyrazoline compound with respect to the polymeric binder is increased, turbidity and opacity may occur. Therefore, the polymer binder can be mixed in a very wide range, and a photoreceptor having favorable charge transport performance and physical properties can be produced.

Since the compatibility is excellent, the charge transport phase is uniform and stable, and as a result, a photoreceptor with high sensitivity, no charging characteristics, and no fog can be obtained, and can form a clear image with high sensitivity. In addition, especially when used in repeated transfer type electrophotography, it is possible to achieve the effect that fatigue deterioration does not occur. The pyrazoline compound used as the charge transport material of the present invention has the role of receiving the charge generated by the charge generating substance and transporting it.

Therefore, in the pyrazoline compound of the present invention, at least one aryl group is an electron-donating group such as an amino group, a dialkylamino group, a diarylamine group, a sialal; ) is preferably substituted with a substituent whose value is negative. The reason for this is presumed to be that these electron-donating groups have the effect of lowering the ionization potential of the compound and making it easier to receive charge injection from a charge-generating substance.

5. Examples Hereinafter, the present invention will be explained in more detail with reference to Examples (II+).

First, the compound of general formula (1), CII) used in the present invention will be specifically illustrated.

Specific examples of the hisazo compound represented by the general formula CI) include those having the following structural formula, but are not limited thereto.

(T-1> (1-2) (1-3) (+-4) (+-5) (+-6) (1-7) (1-8) (1-9) (+-10) (+-11) (1-12) (1-13) (1-14) (1-15) (+-16) 1-1 (1-17) (1-18) (1-19) (1-20) (1-21) (1-22) (1-23) (1-24) (1-25) (+-26) (1-28) (l-29) (1-30) (1-31) (1-32) (1-33) N (1-34) C.N. (1-35) (T-37) C.N. (1-38) (i-3g> − (1-40) (141) (1-42) (1-43) (1-44) (1-45) (+-46) (1-48) (1-49) (1-50) (1-51,) (1-53) 0”-ゝ..

(1-56) (1-57) (1-58) (1-59) (1-60) (1-61) (+ -62) (1-63) -64) (+ -66) (1 -67) (1-68) (1-69) (1-70) (1-72) (1-73) (1-74) (1-75) (+-76) (1-78) CN ( 1-7!1) CN is 113+;113 (1-80) CN (j! ” (1-81) (1-82) Next, among the pyrapurine compounds represented by the general formula CI+), the following Those represented by the general formula (IIa) are preferred.

General formula (Ila): R1ゝ [In this general formula, l represents 0 or 1, ■21'',
.

R1ゞ and R16 are a hydrogen atom, an amino group, a dialkylamino group, a diarylamino group, a dialkylamino group, an alkoxy group, and R'2 and Rjl are as defined above. ] Examples of the pyrazoline compound useful in the present invention represented by the general formula (II) include those having the following structural formula.

(II-1) (II-2) (II-3) (■-4) U-5) (TI-6) OCl-1, (II-7) (11-8) (II-9) (Il -10) (IIMil) II-12) (II-43) (If-14) (II-15) (11-16) (II-17) (TI-13) (II-19) (II-20) The birapurin compound used in the present invention described above is synthesized by a known method, for example, by dehydration condensation with α,β-unsaturated geranylhydrazine in the presence of an acid catalyst.

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

The photoreceptor of the present invention is constructed as shown in FIG. 1, for example. That is, a carrier generation layer 2 containing the above-mentioned bisazo compound as a main component is formed on the conductive support 17,
A carrier transport layer 3 containing the above-mentioned pyrazoline compound as a main component is laminated on this carrier generation layer 21-, and the carrier generation layer 2 and the carrier transport layer 3 constitute a photosensitive layer 4.

Here, the conductive support 1 includes, for example, aluminum, two metals, balanoum, silver, indium, tin, platinum, gold, stainless steel, brass, etc. For example, as shown in FIG. 2, a conductive layer 113 may be provided on an insulating substrate 1Δ'' to constitute a conductive support 1. You can also force it. In this case,
As the substrate 1Δ, a material having flexibility such as paper or a plastic sheet and having sufficient strength against stresses such as bending and tensile stress is suitable. The conductive layer IB can also be provided by laminating metal sheets, vacuum depositing metals, or by other methods.

The carrier generation layer 2 is made of a bisazo compound alone, or a suitable binder resin added thereto, or a substance having a high mobility for carriers of specific or non-specific polarity (i.e., a carrier transporting substance) is added thereto. It can be formed by

Specific forming methods include a method in which the bisazo compound is vacuum-deposited on the support, and a method in which the bisazo compound is dissolved or dispersed in a suitable solvent alone or together with a suitable binder resin, and then applied and dried. can be mentioned.

In this latter method, binder resins or carrier transport substances may be added, in which case
The ratio of carrier generating substance: binder resin: carrier transporting substance is a weight ratio of ゛ζ1:(0-100):(0-50
0), particularly 1:((1-10):(0-50)).

Examples of the solvent or dispersion medium used in the above method include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, monoethanolamine, triethanolamine, triethylenediamine, N,N-
Dimethylformamide, acetone, methyl ethyl chloride
cyclohexanone, hensen, toluene, xylene, chlorine coform, 1,2-dichloroethane, dichloroethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, and others can be used.

Further, as the binder resin, for example, polyethylene,
Polymerized resins such as polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polyphonate resin, silicone resin, melamine resin, etc. , polyaddition type resin, polycondensation type resin, and two of the repeating units of these resins
In addition to insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, etc.
Examples of semiconductors include polymers such as vinyl carbazole. The ratio of this binder resin to the bisazo compound is in the range of 0 to 100% by weight, particularly 0 to 10% by weight.

An appropriate CTM may be added to the CGL2 as necessary.

Further, the carrier generation layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, and the like.

Examples of electron-accepting substances that can be used here include succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride,
Tetrabromo phthalic anhydride, 3-nitro phthalic anhydride 1-isomer, 4-21-1,1 phthalic anhydride, pyromellitic anhydride, norino 1 acid anhydride, tetracyanoethylene, 1-lacyanoquinone methane, 0-dim 1~Lohenzen, In-sh1-mouth・\furan, 1.3.5-)'J nitronhensen, balanitrohendani 1heryl, picrylchloride 1-, quinone chlorimide, chloranil, brumanil,
Dichloro IJ dicyanoparahenzoquinone, anthraquinone, dinitroanthraquinone, 2,7-sinitrofluorenone, 2,4.7-)-linitrofluorenone, 2.4
．． ．． 5.7-Tetranitrofluorenone, 9-fluorenylidene [dicyanomethylene malonodinitrile], polynide o-9-fluorenylidene [dicyanomethylene malonodinitrile], picric acid, O-nitrobenzoic acid, p-nitrobenzoic acid acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5
Examples include -dico-trosalicylic acid, phthalic acid, merino-1-acid, and other compounds with high electron affinity. The addition ratio of the electron-accepting substance is carrier-generating substance:electron-accepting substance-100:0.01 to 20 by weight.
0 preferably 100:0.1-100.

The thickness of the CGL2 formed as follows
Preferably 0.005 to 20 μm, particularly preferably 0.0
05-5 μm. If it is less than 0.005 μm, sufficient photosensitivity cannot be obtained, and if it exceeds 20 μm, sufficient charge retention cannot be obtained.

Further, the above-mentioned CTL3 can be formed by using the above-mentioned birapurin compound in the same manner as above-mentioned CCl2 (that is, melting and dispersing it alone or together with the above-mentioned binder resin and applying and drying). Further, other CTMs may be included.

In this case, the blending ratio of the binder resin and the total carrier transport substance is preferably 10 to 500 parts by weight per 100 parts by weight of the binder resin, and if polycarbonate is used as the binder resin, the total carrier transport substance is preferably 10 to 500 parts by weight per 100 parts by weight of the binder resin. It is preferred to use 20 to 200 parts by weight of total carrier transport material as this provides excellent electrophotographic properties.

Furthermore, the above-mentioned electron-accepting substance can be added to this carrier transport layer to improve sensitivity and further reduce residual potential and fatigue during repeated use. When this electron-accepting substance is added to both the carrier generation layer and the carrier transport layer, the electron-accepting substances added to each layer may be completely or partially the same, or in some cases may be completely different. I don't mind. Note that the electron-accepting substance may be added to either one of the gear transport layers.

The addition ratio of the electron-accepting substance to the carrier-transporting layer is as follows: total carrier-transporting substance:electron-accepting substance=100:o
, ox to 100, preferably 100:0.1 to 50.

The thickness of the gear carrier transport 1<;i3 formed in this way is 2 to 100 μm, preferably 5 to 3011 m.

The present invention has been explained above according to the specific structural example shown in FIG. 1 or FIG. This is sufficient, and the mechanical structure of the electrophotographic photoreceptor can be arbitrarily selected.

For example, as shown in FIG. 3, a suitable intermediate layer 5 may be provided on the conductive support 1, the carrier generation layer 2 may be formed through this, and the carrier transport layer 3 may be formed thereon. . This intermediate layer 5 has a function of preventing free carriers from being injected into the photosensitive layer 4 from the conductive support 1 when the photosensitive layer 4 is charged, and also has the function of preventing the photosensitive layer 4 from being injected into the photosensitive layer 4 when the photosensitive layer 4 is charged. It can have a function as an adhesive layer for adhering to. Examples of the material for the intermediate layer 5 include metal oxides such as aluminum oxide and indium oxide, acrylic resin, melamine resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin,
Polymer materials such as polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, etc. can be used.

Further, as shown in FIG. 4, a carrier transport layer 3 is formed on the conductive support 1 with or without the intermediate layer 5, and a carrier generation layer 2 is formed thereon. Layer 4 may also be configured.

Further, FIG. 5 shows a structure in which the above carrier-generating substance (hisazo compound) is dispersed in a carrier-transporting phase containing the above-mentioned pyrazoline compound (i.e., a carrier-generating substance phase and a carrier-transporting substance phase). consisting of a mixed layer of )ff
An example in which an i-layer photosensitive layer is formed is shown.

Hereinafter, the present invention will be explained in detail with reference to specific embodiments.

A conductive bamboo skin made of polyethylene terephthalate with a thickness of 100 μm on which aluminum has been vapor-deposited is coated with a vinyl chloride-vinyl acetate-maleic anhydride copolymer [from Esresoku MF-10J (Sekisui Chemical Co., Ltd.)]. An intermediate layer with a thickness of approximately 0.1 μm is provided. Next, 2 g of the hisazo compound represented by the structural formula (r-57>) was dispersed with 100 me of 1,2-dichloroethane in a ball mill for 12 hours, and the resulting dispersion was placed on the intermediate layer using a doctor blade. Apply -ζ and dry thoroughly to a thickness of about 0.
A 3 μm CGL was formed.

On the other hand, 11.25 g of the birapurin compound shown by the above-mentioned structural formula (+1-14.) and 15 g of polycarbonate resin [Panlite L-1250J (Teijin Kasei M) were mixed in 100 m It of 1,2-dichloroethane. The resulting solution was melted and applied onto the CGL using a doctor blade, and dried at a temperature of 80°C for 1 hour to form a CGL with a thickness of 12 μm.
A TL was formed, thereby producing an electrophotographic photoreceptor according to the present invention. This will be referred to as "Sample 1".

In the formation of CGL, the bisazo compounds shown by the structural formulas (1-81), (I-55), (17-41) and (1-82) were used, respectively. Other than that, four types of electrophotographic photoreceptors based on the present invention were manufactured in the same manner as in Example 1. These were named "Sample 2,""Sample3,""Sample4," and "Sample 5," respectively. do.

Implementation side Tamaji 1 In the formation of CTL, the present invention was carried out in the same manner as in Example 1, except that the compounds represented by the structural formulas (II-19) and (II-20) described above were respectively used as pyrazoline compounds. (An electrophotographic photoreceptor was manufactured.

These will be referred to as "sample 6" and "sample 7j."

1 An intermediate layer was provided on the conductive support in the same manner as in Example 1, and 2 g of the bisazo compound represented by the structural formula (I-1) and polycarbonate-1 resin "Panlite T," -1
250j 1 g and 1,2-cycloethane 100
The resulting dispersion was applied to the intermediate layer using a doctor blade and sufficiently dried to form a CGL with a thickness of about 0.5 μm.

On these C and GL, CT 1. , thereby producing an electrophotographic photoreceptor according to the present invention. This will be referred to as 1-sample 8.

A comparative electrophotograph was taken in the same manner as in Example 1, except that in the formation of CTL in Example 1, a pyrazoline compound having the following structural formula was used instead of the pyrazoline compound represented by general formula (II). A photoreceptor was manufactured. This will be referred to as "comparative sample 1."

In the formation of CTL in Example 1, a comparative electron was prepared in the same manner as in Example 1, except that an oxadiazole derivative having the following structural formula A was used instead of the pyrazoline compound represented by the general formula (It). A photographic photoreceptor was manufactured. this"
"Comparative sample 2".

Structural formula A: For each of the electrophotographic photoreceptors obtained as described above (Samples 1 to 8 and Comparative Samples 1 and 2), "Electrometer 5l)-428 Model" manufactured by Kawaguchi Electric Seisakusho) was used. The electrophotographic properties were investigated using this method. That is,
Acceptance potential V8 (V) when the surface of the photoreceptor is charged at a charging potential of -6 KV for 5 seconds, and exposure # required to attenuate the potential (initial potential) Vl after 5 seconds of dark decay to %.
E! 4 (lux·sec). The results were 1ffI shown in Table 1 below.

(The following is a blank space, continued on the next page) Table 1 Also, Samples 1 to 6, Comparative Sample 1 and Comparative Sample 2
Dry type electrophotographic copying machine rU-Bix2000RJ
(manufactured by Konishiroku Photo Industry Co., Ltd.) for continuous copying, and the black paper potential Vb (V, ) and white paper potential VW (■) at an exposure aperture value of 1.0 are determined by [Elect! The measurement was made using a Static Voltmeter 1441]-ID type (manufactured by Monroe Electronics Inc.) immediately before development.

The results were as shown in Table 2 below.

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 or 3 as the original, and the white paper potential refers to the surface potential of the photoreceptor when the copying cycle described above is performed using a black paper with a reflection density of 1 or 3 as the original. represents the surface potential of the photoreceptor at that time.

(Margin below, continued on next page) Tomo-'2 (However, ΔVb (V) and ΔVw (V) in the above table represent the amount of variation in black paper potential Vb (V) and white paper potential ■7 (V), respectively. (O represents an increase in the fluctuation amount, and O represents a decrease.) As is clear from the above results, based on the present invention, the electrophotographic photoreceptor has sufficient photosensitivity, and is subjected to repeated electrophotography. Even when subjected to a process, the potential history state is maintained stably, and a large number of visible images of good quality can be stably formed.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIGS. 1, 2, 3, 4, and 5 are sectional views of five examples of electrophotographic photoreceptors. In addition, in the symbols shown in the drawings, 1......Substrate 2...Carrier generation layer (CG L) 3
......Carrier transport layer (CTL) 4...
...It is a photosensitive layer. Agent: Patent attorney Hiroshi Aisaka (and 1 other person) Sakae 1 Figure 4 361

Claims (1)

[Scope of Claims] 1. A photoreceptor having a photosensitive layer consisting of a carrier generation phase and a carrier transport phase, wherein the carrier generation phase contains a bisazo compound represented by the following general formula CI), and the carrier transport phase contains a bisazo compound represented by the following general formula CI). A photoreceptor characterized by containing a pyrazoline compound represented by the following general formula (II). General formula [I]: A-N=N-Ar'-C=C-Ar2-N=N-A1 1R2 [However, in this general formula, Arl and Ar2: each substituted or unsubstituted carbocyclic aromatic group ring group, or substituted or unsubstituted heterocyclic aromatic ring group, - R1 and R2: each electron-withdrawing group or hydrogen atom (however, R1 and R2 are small (both one is an electron-withdrawing group), A : (Y)m Y χ A (X is a hydroxy group, -NH3O2-R6, <However, R4 and R'h are each a hydrogen atom, a substituted or unsubstituted alkyl group, and R6 is a substituted or unsubstituted alkyl group. Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxyl group, a sulfo group, or a substituted or unsubstituted sulfamoyl group (provided that m is When there are two or more groups, they may be different from each other.) Z is an atomic group necessary to constitute a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring. , R3 is a hydrogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof, A' is a substituted or unsubstituted aryl group, n is 1 or an integer of 2, m is an integer of 0 to 4)] General formula [■]: HRI11' 1 R''-C-C-H 18 [However, in this general formula, β: 0 or 1, R7, R8 and R9, substituted or unsubstituted aryl group, R and I?+1: hydrogen atom, argyl group having 1 to 4 carbon atoms, or substituted or unsubstituted aryl group or aralkyl group (provided that R1(+ and RII are not both hydrogen atoms, and when β is O, R is not a hydrogen atom.)]