JPH0212259A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity, and to prevent rise of residual potential and change of characteristics due to repeated uses by forming a photosensitive layer containing a specified squarium compound on a conductive substrate. CONSTITUTION:The photosensitive layer 4 formed on a conductive substrate 1 contains at least one of the squarium compounds represented by formula I in which Ar1 is a group of formula II; Ar2 is a group of formula III or the like; each of R0-R2 and each of R10-R12 are each H, alkoxy, or the like; each of R3-R6 and each of R13 and R16 is each halogen, optionally substituted or unsubstituted alkyl or the like; R9 is optionally substituted or unsubstituted alkyl; and Ar5 is optionally substituted or unsubstituted phenyl or naphthyl or the like, thus permitting electrophotographic characteristics, such as sensitivity, residual potential resistance, and potential stability to be enhanced, and fatigue deterioration at the time of repeated uses to be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a specific squareium compound.

[Prior Art] Conventionally, as electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic light guiding compound such as selenium, zinc oxide, cadmium sulfide, silicon, etc. have been widely used. However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, manufacturing cost, etc. For example, when selenium crystallizes, its properties as a photoreceptor deteriorate, making it difficult to manufacture.Also, selenium crystallizes due to heat, fingerprints, etc., and its performance as a photoreceptor deteriorates. In addition, cadmium sulfide has problems in moisture resistance and durability, and even zinc oxide has problems in durability.

In order to overcome these drawbacks of the Kuroiso photoreceptor, research and development have been actively conducted in recent years on organic photoreceptors having photosensitive layers containing various photoconductive compounds as main components. For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole lintro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability.

In order to improve these drawbacks, attempts have been made to develop organic photoreceptors with higher performance by assigning the carrier generation function and the carrier transport function to different substances. Many studies have been conducted on such so-called function-separated type photoreceptors because each material can be selected from a wide range and a photoreceptor having arbitrary performance can be produced relatively easily.

[Problems to be Solved by the Invention] A large number of compounds have been proposed as carrier-generating substances in the cryogenic separation type electrophotographic photoreceptor as described above. An example of using an inorganic compound as a carrier generating substance is amorphous selenium described in Japanese Patent Publication No. 43-16198, which is used in combination with an organic photoconductive compound. However, the drawback that the carrier generation layer crystallizes due to heat and deteriorates the characteristics as a photoreceptor has not been improved.

In addition, many electrophotographic photoreceptors using organic dyes or organic pigments as carrier-generating substances have been proposed. Typical examples include bisazos, trisazos, phthalocyanines,
Viryliums, squareiums, etc. are known.
Phthalocyanines, 1-lisazos, and squareiums have been reported to have sensitivity from the visible region to the near-infrared region.

However, phthalocyanines have the disadvantage that their spectral sensitivity is biased toward long wavelengths and poor red reproducibility, and trisazo compounds have poor electrical properties and insufficient sensitivity1.

Although the squalium compounds disclosed in Japanese Patent Application Laid-open No. 49-105536 have relatively high sensitivity, they have drawbacks in chargeability, dark decay, etc., and have not been able to achieve both high sensitivity and low dark decay.

Furthermore, in recent years, as a light source for electrophotographic photoreceptors,
Gas lasers such as He-Ne lasers and semiconductor lasers are beginning to be used. These lasers are characterized by being capable of 0N10FF in time series, and are particularly promising as a light source for copying machines and computer output printers with image processing functions, such as intelligent copiers. Among these, semiconductor lasers are attracting attention because their nature does not require electrical signal/optical signal conversion elements such as acoustic engineering elements, and they can be made smaller and lighter. However, this semiconductor laser has a low output compared to a gas laser, and the emission wavelength is long (approximately 780 nm or more), so in many conventional electrophotographic photoreceptors, the spectral sensitivity is on the short wavelength side. There were no practically satisfactory sensitivity characteristics.

[Object of the Invention] An object of the present invention is to provide an electrophotographic photoreceptor containing a specific squareium compound having excellent carrier generation ability.

Another object of the present invention is to provide a durable electrophotographic photoreceptor that has high sensitivity, a low residual potential, and whose characteristics do not change even after repeated use.

A further object of the present invention is to provide an electrophotographic photoreceptor containing a squareium compound that acts as a sharpening material even in combination with a wide variety of carrier transport materials. It is in.

Still another object of the present invention is to provide an electrophotographic photoreceptor that has sufficient practical sensitivity even to long wavelength light sources such as semiconductor lasers.

Still other objects of the present invention will become apparent from the description herein.

[Means for Solving the Problems] As a result of intensive research to achieve the above object, the present inventors discovered that a specific squalium compound can act as an active ingredient of an electrophotographic photoreceptor. This completes the present invention.

That is, the object of the present invention is to provide on a '4-electric support,
This is achieved by an electrophotographic photoreceptor characterized by having a photosensitive layer containing a squalium compound represented by the following general formula [I] or [II].

[In the formula, Ar1 and Ar2 are different from each other, one of Ar1 and Ar2 is selected from the following general formula [A], and is -3O2-Ra (R7 and R8 are each a hydrogen atom, a substituted or unsubstituted represents an alkyl group or a phenyl group). R3, R4.

R5 and R6 are each a hydrogen atom, a halogen atom,
Or represents an alkyl group. R9 represents a substituted or unsubstituted alkyl group. ) and Ar+ and Ar2
The other is the following general formula [B], [C], [01 and [E
] selected from one of the group consisting of

(Ro, R+ and R2 are each hydrogen atom, halogen atom, alkyl group, alkoxy group, hydroxyl group or NH
Represents Y. Y is -C-R7 or (in the formula, R+o, R
h and R+2 are Ro and R+ of general formula [A], respectively
, R2, and R13°R+4. R+5 and 1
Dog 16 has R3 and R4 in the general formula [Δ], respectively.
, Rs and R6, and Ar5 represents a substituted or unsubstituted phenyl group, naphthyl group, anthranyl group, fused polycyclic group or heterocyclic group. ) General formula [C] -Xi (wherein, R17 and Rta are each represented by the general formula [C]
A] has the same meaning as Ro, R+ and R2. ×1
to form a substituted or unsubstituted aliphatic hydrocarbon ring, a substituted or unsubstituted aliphatic heterocycle, a substituted or unsubstituted aromatic hydrocarbon ring, or an M operator or an unsubstituted aromatic heterocycle Represents the required atomic group. Rls and R2O
each represents a substituted or unsubstituted alkyl group.

) General formula [D] and each represents a group of atoms necessary to form a ring having at least 5 members as a whole. ) General formula [E] (wherein, R27, R28, R29 and R30 have the same meanings as Ro, R+ and R2 in general formula [A], respectively. R3+ represents a substituted or unsubstituted alkyl group. Ars represents a substituted or unsubstituted naphthyl group, anthranyl group, fused polycyclic group or heterocyclic group. It is.R
26 represents III or an unsubstituted alkyl group.

(In the formula, R34, R35 and R36 are respectively synonymous with Ro, R+ and R2 in the general formula [A].
3? , R36, R39 and R40 have the same meanings as Ra, R, Rs and R6 in general formula [A], respectively. Ar7 represents a substituted or unsubstituted aryl group. )] [In the formula, Ara and Ars are different from each other,
One of Ara and Ars is selected from the following general formula [A], and the other is selected from the general formula [A'].

General formula [A] General formula [A'] (wherein, Ro
, R1 and R2 and Ro'R+ ' and R2 each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, water 11) J or NHY, and Y is -C-
R7 or -302-R8 (R7 and R8 each represent an alkyl group, a phenyl group, or a hydrogen atom that may have a substituent). R3, R4.

R5 and R6 each do not represent a hydrogen atom, an alkyl group or a halogen atom. R9 and R9 each represent a substituted or unsubstituted alkyl group. However, Ro and R
o', R+ and R+', R2 and R2', R3
and R3', R→ and R4' * At least one of R5 and R5', R6 and R6', and R9 and Rs' are not the same. ) Hereinafter, the squalium compound of the present invention will be specifically shown.

The squalium compound of the present invention is represented by the general formula [I], of which either Ar1 or Ar2 is selected from the above-mentioned general formula [A].

In the general formula [Ai, the alkyl group represented by Ro, R+ and R2 is preferably an alkyl group having 1 to 7 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. This alkyl group includes those having a substituent, and representative examples of the substituent include a halogen atom, water a
ll, an alkoxy group, and the like. Specific examples of the alkyl group include a methyl group, an ethyl group, a chloromethyl group, and the like, and among these, a methyl group is preferred.

Examples of the halogen atom represented by Ro, R+, and R2 include a chlorine atom, a bromine atom, a fluorine atom, and the like.

The alkoxy group represented by Ro, R+ and R2 preferably has 1 to 7 carbon atoms, and specific examples thereof include a methoxy group and an [.oxy group.

Y of NHY represented by Ro, R+ and R2 is -C-
Although R7 or -302-Ra is shown, examples of the alkyl group which may have a substituent for R7 and R8 include a methyl group, an ethyl group, a propyl group, and the like. Examples of the phenyl group include a phenyl group and anisoyl group.

Examples of the alkyl group for R9 include methyl group, ethyl group, propyl group, heptyl group, and the like.

In general formula [8], examples of the substituent for Ar+ include an alkyl group, an alkoxy group, a halogen atom, a cyano group, an ester group, an acyl group, a dialkylamino group, a dialkylamino group, and a diarylamino group. can.

Substituent for R26 in general formula [0], substituent for Ar2 in general formula [E], Ar3 in J3 in general formula [F]
Examples of the substituent include the same substituents as the above-mentioned substituent for Ar+.

Specific examples of the squalium compound useful in the present invention are shown below, but the squalium compound of the present invention is not limited thereto.

-i 1-7 B-9 r:5r B-24 B-25 B-40 B-41 ○ B-56 B-57 Margin below C-5 C-20 C-21 C-34 C-35 gate Margin et al. below D-2 D-1゜ L)-12 death D-19 D-20 D-37 D-38 D' D' D' D' D' D' D' D' D' 1.7. :’, “　”, τ Margin below D' D' D' D' D’　　　-18 D’　　　-19 D'-20 D’-21 ○ D’　　　-14 D'-15 D’　　　-16 D’　　　-17 D' D'-23 D’　　　-24 D' D'-26 Shil D'-27 D'-28 D'-29 D’　　　-30 D' D' D' D' D' D' D' D' D' D' D' D' D'-43 D' D' D' D' D' D' D' death death D' D’　　　-48 D' D' D' D' D' D' D' D' D' D' vinegar In I, :1 D' D' D' D' E-5 E-20 E-21 CH.

E-37 E-38 F-5 113 F-t.

F-20 F-21 Exemplary compound of general formula [ffl f-2 I-9 ■-10 ■-11 ■-12 ■-5 f-8 ■-13 ■-14 ■-15 ■-16 ■-17 ■ -18 ■-19 ■-20 ■-25 ■-26 ■-28 ■-21 ■-22 ■-23 ■-24 ■-30 ■-31 ■-32 ■-33 ■-34 ■-35 ■-36 ■-37 ■-43 ■-44 ■-45 ■-38 ■-39 f-40 ■-41 ■-42 ■-47 ■-48 ■-49 ■-50 Represented by general formula [I] or [■] Examples of the squalium compound of the present invention are disclosed in JP-A-62-267753 and Tetrahedron Letters.
etters) No, 10. pp, 781-782
．． 1970 and Synthesis
pp. 961.1980. For example, the squalium compound of general formula [I] can be synthesized in four steps as shown by the formula below.

In the first step, thionyl chloride and N,N-dimethylformamide are added to squaric acid of formula (A), and the mixture is heated to about 100°C.
3,4-dichloro-3-cyclobutene-1
, 2-dione is obtained.

In the second step, the 3゜4-dichloro-3-cyclobutene-1,2-dione of formula (B) obtained in the first step is added to
5 molar ratio of Ar2-H of formula (C) and the above Ar2 in a solvent.
The compound of formula (D) is obtained by reacting in the presence of AlCl3 in a molar ratio of 1 or more to -@ at a temperature of v temperature or lower.

Examples of the solvent used in the second step include dichloromethane, carbon tetrachloride, 1,2-dichloroethane, and other solvents commonly used in Friedel-Krach reactions. Further, instead of AjICffi3, a Lewis acid such as aluminum chloride, antimony chloride, iron chloride, titanium chloride, boron trifluoride, tin chloride, bismuth chloride, or zinc chloride may be used as a catalyst.

In the third step, the compound of formula (D) obtained in the reaction of the second step is hydrolyzed to form a compound of formula (E).

Hydrolysis can be carried out, for example, by refluxing in a vinegar solution containing a small amount of water.

In the fourth step, the compound of formula (E) obtained and isolated in the third step is refluxed in a solvent or by a reduced pressure method to obtain Ar1-H of formula (F).
are reacted to obtain the desired squalium compound (I). The solvent used here has 2 to 1 carbon atoms.
0 primary or secondary alcohols, or azeotropic mixtures of these alcohols and aromatic hydrocarbons such as benzene, toluene, and xylene can be used.

The squalium compound of the present invention can also be obtained by a general synthesis method for squalium compounds. That is, a total of 2 moles of two different types of amine derivatives can be simultaneously reacted with 1 mole of squaric acid. However, the squalium compound obtained in this case is a mixture of an asymmetrical squalium compound and a symmetrical squalium compound, and it is difficult to control the ratio of the products and separate and purify each product, and the electrical properties vary widely and the sensitivity is low. The former method is preferable since it has problems such as lowering the performance.

Next, a specific method for synthesizing Squarium of the present invention will be described below.

Synthesis example (synthesis of exemplified compound B-5) (Synthesis of dicyclobutenedione (B)) Squaric acid 1
00g to benzene 5001112 and thionyl chloride 14 (
Add h12 and 51 g of N,N-dimethylformamide,
Stir at an external temperature of 100°C for 2 hours. After distilling off the solvent,
Crystallize from n-hexane. After washing with n-hexane several times by decantation, drying under reduced pressure, dicyclobutenedione (B
) 58g (yield 44%) (Synthesis of chloride (D)) 53g of aluminum chloride is added to 36011 methylene chloride and stirred at about 0°C. Dicyclobutenedione (B) 5
After adding 09, indoline derivative (C) 77o was dissolved in methylene chloride 180-, and while keeping the internal temperature at 0°C,
Drip. Stir at internal O 0 C for 4 hours.

Methylene chloride 1! and distilled water 12 are added, stirred, and left to stand still to obtain a methylene chloride layer. After washing with water, dry with a sieve, and methylene chloride is distilled off under reduced pressure. M was prepared using a silica gel column to obtain 90 g (yield: 75%) of the chloride (D) as crystals.

(Synthesis of OH form (E)) 1 g of acetic acid io and 10 g of distilled water are added to 30 g of chlorine form (D), and heated under reflux for 3 hours with stirring.

After cooling, add distilled water (42), add hydrochloric acid (50112), stir, and filter through a suction funnel. Washing with water, n-hexane, and drying under reduced pressure gave OH form (E) 24(+ (yield: 84%)) as crystals.

(Synthesis of Exemplary Compound B-5) OH form (E) 24(] 1.:1- to 79/-/I/1
ft and Compound (F) 9.41;l were added, and the mixture was heated and refluxed under reduced pressure for 2 hours. Filter with suction while hot and wash three times with acetone 22. After drying under reduced pressure, 13 g of the target exemplary compound B-5 was obtained as green crystals (yield: 42
%)Obtained.

Elemental analysis HN calculated value (%), 73.20 5.24 6.3
3 Actual failure value (%) 73.15 5.27 6.2
8-spectral absorption spectrum (in methylene chloride) λll1ax
=637nn Infrared absorption spectrum (in KBr) vvaa* -1590cm-' (c-0) Melting point (Japanese Pharmacopoeia melting point measurement method) 238°C The squalium compound of the present invention has excellent photoconductivity. When producing a photoreceptor using a photoreceptor, it can be mounted by providing a photosensitive layer in which the squareium compound of the present invention is dispersed in a binder on a conductive support. Among photoconductors, a so-called functionally separated photoreceptor is constructed by using it as a carrier-generating substance by taking advantage of its particularly excellent carrier-generating ability, and using it together with a carrier-transporting substance that can effectively act in combination with this. , particularly good results are obtained. The functionally separated photoreceptor may be of a dispersed type, but it is more preferably a laminated type photoreceptor in which a carrier generation layer containing a carrier generation substance and a carrier transport layer containing a carrier transport substance are laminated.

When the squalium compound of the present invention is used as a carrier-generating substance, carrier-transporting substances that can be used in combination with it include electron-accepting substances that easily transport electrons, such as trinitrofluorenone or tetranitrofluorenone, as well as polyesters. - Polymers having a heterocyclic compound in the side chain as represented by N-vinylcarbazole, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, dracin derivatives, amino Examples of electron-donating substances that easily transport holes include substituted carbon derivatives, triarylamine derivatives, carbazole derivatives, stilbene derivatives, phenothiazine derivatives, azine derivatives, butadiene derivatives, Schiff base derivatives, etc., and the carrier transport used in the present invention The substances are not limited to these.

Various types of mechanical configurations of photoreceptors are known, and the photoreceptor of the present invention can take any of these forms.

Usually, the configuration is as shown in FIGS. 1 to 6. FIG. 1 shows an example of a photoreceptor for negative charging, in which a carrier generation layer 2 containing the above-mentioned squareium compound as a main component on a conductive support 1,
This is a case in which a photosensitive member 114 is provided on which a carrier transporter 13 containing a carrier transporting substance as a main component is provided in a laminated configuration.

FIG. 2 shows an example of a photoreceptor for positive charging, in which a carrier generator 112 is provided on the carrier transport layer 3. As shown in FIG.

In this case, in order to protect the carrier generation layer, it is desirable to form an overcoat layer or an intermediate layer on the carrier generation layer.

Various binders can be used for the overcoat layer, but acrylic resins, isocyanate resins, etc. are preferable. Furthermore, tin oxide, titanium oxide, etc. can also be dispersed in the binder.

As the intermediate layer, the same binders as those for the overcoat layer, gold i oxide, etc. can be used. Furthermore, compounds containing silicon or zirconium can also be used.

As shown in FIGS. 3 and 4, this photosensitive material 114 may be provided via an intermediate WJ 5 provided on a conductive support.

When the photosensitive layer 4 has a two-layer structure in this manner, a photoreceptor having the most excellent electrophotographic properties can be obtained. Further, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 formed by dispersing the carrier-generating substance 7 and a carrier-transporting substance in M6 is formed directly on the conductive support 1 or as an intermediate layer. 5 may be provided.

The carrier generation layer 2 constituting the photosensitive layer 1114 having a two-layer structure is placed directly on the conductive support 1 or the carrier transport layer 3.
Alternatively, it can be formed, for example, by the following method, after providing an intermediate layer such as an adhesive layer or a barrier layer, if necessary.

M-1) A method of applying a solution in which the squalium compound of the present invention is dissolved in a suitable solvent, or a solution in which a binder is added and mixed as necessary.

M-2) Ball milling the squalium compound of the present invention,
A method in which fine particles are made into fine particles in a dispersion medium using a homomixer, etc., and a binder is added as necessary to mix and disperse the resulting dispersion.

Examples of the solvent or dispersion medium used for forming the carrier generation layer include lobethylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methylethylketone, cyclohexanone, penzene, Toluene, xylene, chloroform, 1,2-dichloroethane, 1.1.24lichloroethane, 1,1.1-trichloroethane, trichloroethane, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate , butyl acetate, dimethyl sulfoxide and the like.

When using a binder in the carrier generation layer or carrier transport layer, any binder can be used, but it is preferable to use a film-forming polymer that is hydrophobic, has a high dielectric constant, and is electrically insulating. preferable. Examples of such high molecular weight polymers include the following:
It is not limited to these.

P-1 Polycarbonate P-2 Polyester P-3 Methacrylic 41 Fat P-4 Acrylic resin P-5 Polyvinyl chloride P-6 Polyvinylidene chloride P-7) Polystyrene P-8) Polyvinyl acetate P-9) Styrene-butadiene co Polymer p-10) Vinylidene chloride-acrylonitrile copolymer p-11) Vinyl chloride-vinyl acetate copolymer p-12
) Vinyl chloride-vinyl acetate-maleic anhydride copolymer p-13) Silicone resin p-14) Silicone-alkyd resin p-15) Phenol formaldehyde resin p-16) Styrene-
Alkyd resin p-17) Poly-N-vinylcarbazole P-18) Beaurivinyl butyral p-19) Polyvinyl formal p-20) Vinyl acetate resin P-21) Epoxy resin These binders can be used alone or in combination. It can be used as a mixture of more than one species.

The thickness of the carrier generation layer 2 formed in this way is
It is preferably 0.01 .mu.s to 20 .mu., more preferably O,OS .mu. to 5 .mu.. Further, when the carrier generation layer or the photosensitive layer is a dispersed type, the particle size of the squalium compound is preferably 5 μm or less, more preferably 1 μm or less.

As a conductive layer, a conductive compound such as titanium oxide, tin oxide, copper iodide, etc., carbon,
It can be formed by dispersing an organic conductive compound such as an organic semiconductor or a conductive polymer in a binder or by applying it as it is.

The squalium compound of the present invention can be subjected to various processes to improve its dispersibility from the viewpoint of powder and granule engineering. For example, wet granulation, spray drying, freeze drying, dry pulverization, etc. can be used.

Further, by changing the crystal form, electrophotographic performance and dispersibility can be improved. For example, the crystal form may change depending on the method of dissolving with an organic amine and then neutralizing and precipitating with an acid, or depending on pressure, temperature, etc.

The conductive support used in the photoreceptor of the present invention includes a metal plate including an alloy, a metal drum, a conductive polymer,
Examples include paper, plastic films, etc. that have been made conductive by coating, vapor depositing, or laminating a thin layer of a metal such as aluminum, palladium, or gold containing a conductive compound or alloy such as indium oxide.

For intermediate layers such as adhesive layers or barrier layers, in addition to the polymer used as the binder, organic polymers such as polyvinyl alcohol, ethyl cellulose, and carboxymethyl cellulose, or aluminum oxide are used.

The photoreceptor of the present invention has the above-described structure, and as is clear from the examples described later, it has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and is particularly resistant to fatigue even when used repeatedly. It has little deterioration and excellent durability.

[Examples] The present invention will be specifically explained below using Examples, but the embodiments of the present invention are not limited thereto.

(Example 1) In a 300112 stainless steel pot, 0.75 o of polyvinyl butyral resin (trade name, XYHL), 1 g of tetrahydrofuran iso, and Squarium compound B-5i,
sg, add Glass Peas 1501Q, and disperse with a sand grinder for 48 hours. This dispersion was applied onto an aluminum vapor-deposited base using a wire bar so that the film thickness after drying was approximately 0.2μ, and a carrier generation layer (CGL) was formed.
was formed. Next, 7.5 g of polycarbonate resin (trade name, Panlite K-1300) and 50 g of ethylene chloride were added.
1 g of the following carrier transport substance and -14,0 liters are mixed using a magnetic stirrer. This liquid was applied onto the CGL using an applicator so that the film thickness after drying was 20 μm to form a carrier transport II (CTL).

After being placed in the oven and thoroughly dried, the electrophotographic performance was tested. That is, after being charged by performing a corona discharge of 16 KV for 5 seconds using an electrostatic copying tester manufactured by Kawaguchi Electric,
Leave it in a dark place for 5 seconds, measure its surface potential V^, then irradiate the photosensitive layer with a tungsten halogen lamp with an illuminance of 14 lux, and calculate the time until the surface potential becomes half of ■^. Then, the half-decreased exposure m E 1/2 was determined. As a result ■＾--1300V, ε1/2-2.9 I
It was ux-sec.

Next, image characteristics and durability were evaluated using a Konica N LD printer (semiconductor laser with light @ 790nta±10nm).
Tested with. Good images were obtained in a picture printing test of up to 10,000 sheets.

Examples 2 to 20 In Example 1, photoreceptors were prepared by changing the carrier generating material (CGM) B-5 and the carrier transporting material (CTM) K-1 as shown in Table 1, and the photoreceptors were prepared in the same manner as in Example 1.゛The electrophotographic performance was evaluated. The results are shown in Table 1.

Table 1 The CTMs in Table 1 are shown below.

ni-2 ni-3 ni-4 ni-5 ni-10 ni-13 ni-6 ni-7 ni-8 ni-9 ni-18 The CTMs in Table 2 are shown below.

Example 21 A photoreceptor was produced and tested in the same manner as in Example 1, except that the order of application of CGL and CTL was reversed. (However, the corona charge was set to +6KV.) The results are VA
=1500V, El/2 = 2.5 lux・se
It was c. In addition, the images in the image display test of up to 10,000 sheets were good.

Example 22 - Cattle O In Example 21, a photoreceptor was prepared by changing the carrier generating substance (CGM) B-5 and the carrier transporting substance (CTM) K-1 as shown in Table 2, and the photoreceptor was prepared in the same manner as in Example 21. The electrophotographic performance was evaluated. The results are shown in Table 2. P items...Ichikuichi -21 -22 -23 -24 -25 -28 -36 -29 -30 -31 -32 Effects] According to the present invention, by using the squalium compound represented by the general formula [I] or [II] as a photosensitive material constituting the photosensitive layer of an electrophotographic photoreceptor,
It has excellent electrophotographic properties such as sensitivity, residual potential, and charge retention, has little fatigue deterioration when used repeatedly, is stable against heat and light, and has sufficient sensitivity even in the long wavelength region of 78001 or more. At the same time as having 780
An excellent electrophotographic photoreceptor that can be used satisfactorily even in the visible light range of nm or less can be produced. Further, by using the squalium compound of the present invention, it is possible to provide a photoreceptor having sufficient sensitivity even in combination with a wide range of carrier transport substances.

[Brief explanation of the drawing]

1 to 6 are sectional views showing examples of the mechanical structure of the electrophotographic photoreceptor of the present invention, and 1 to 7 in the figures represent the following, respectively. 1... Conductive support 2... Carrier generation layer 3... Carrier transport layer 4... Photosensitive layer 5... Intermediate layer 6... Layer containing carrier transport substance 7... Carrier generation material

Claims (6)

[Claims] (1) An electrophotographic photoreceptor comprising, on a conductive support, a photosensitive layer containing at least one squarium compound represented by the following general formula [I]. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, Ar_1 and Ar_2 are different from each other,
One of _1 and Ar_2 is selected from the general formula [A] below, and the general formula [A] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_0, R_1 and R_2 are hydrogen atoms, halogen atoms, alkyl groups, alkoxy represents a group, a hydroxyl group, or NHY.
hydrogen atom, substituted or unsubstituted alkyl group,
Or represents a substituted or unsubstituted phenyl group. ). R_3, R_4, R_5 and R_6 each represent a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group. R_9 represents a substituted or unsubstituted alkyl group. ) The other of Ar_1 and Ar_2 is selected from the following general formulas [B], [C], [D], or [E]. General formula [B] ▲ There are mathematical formulas, chemical formulas, tables, etc.
_6 are R_3 and R_4 in general formula [A], respectively
, R_5 and R_6, and Ar_5 represents a substituted or unsubstituted phenyl group, naphthyl group, anthranyl group, fused polycyclic group or heterocyclic group. ) General formula [C] ▲ Numerical formulas, chemical formulas, tables, etc. Represents the atomic group necessary to form an aliphatic hydrocarbon ring, a substituted or unsubstituted aliphatic heterocycle, a substituted or unsubstituted aromatic hydrocarbon ring, or a substituted or unsubstituted aromatic heterocycle.
1_9 and R_2_0 each represent a substituted or unsubstituted alkyl group. ) General formula [D] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_2_3, R_2_4 and R_2_5 are R_0, R_1 and R_2 in general formula [A], respectively)
is synonymous with R_2_6 represents a substituted or unsubstituted alkyl group. X_2 contains at least one heteroatom in addition to the carbon atom group or nitrogen atom necessary to form at least a 6-membered saturated or unsaturated monocyclic hydrocarbon or polycyclic hydrocarbon, and at least 5-membered in total. Each represents a group of atoms necessary to form a ring. ) General formula [E] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_2_7, R_2_8, R_2_9 and R_
3_0 are R_0 and R in general formula [A], respectively.
Synonymous with _1 and R_2. R_3_1 represents a substituted or unsubstituted alkyl group. Ar_6 represents a substituted or unsubstituted naphthyl group, anthranyl group, fused polycyclic group or heterocyclic group. ) General formula [F] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_3_4, R_3_5 and R_3_6 are R_0, R_1 and R_2 in general formula [A], respectively)
is synonymous with R_3_7, R_3_8, R_3_9 and R_4_0 are R_3 in general formula [A], respectively.
, R_4, R_5 and R_6. Ar_7 represents a substituted or unsubstituted aryl group. )] (2) An electrophotographic photoreceptor comprising, on a conductive support, a photosensitive layer containing at least one squarium compound represented by the following general formula [II]. General formula [II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, Ar_8 and Ar_9 are each different from each other, and one of Ar_8 and Ar_9 is the following general formula [A]
and the other is selected from general formula [A']. General formula [A] General formula [A'] ▲There are mathematical formulas, chemical formulas, tables, etc.▼▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_0, R_1 and R_2 and R_0', R
_1' and R_2' are each a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or NHY
represents. Y represents ▲a numerical formula, chemical formula, table, etc.▼ or -SO_2-R_8 (R_7 and R_8 each represent an alkyl group, phenyl group, or hydrogen atom that may have a substituent), R_3, R_4, R_5
and R_6 each represent a hydrogen atom, an alkyl group or a halogen atom. R_9 and R_9' each represent a substituted or unsubstituted alkyl group. However, R_
0 and R_0', R_1 and R_1', R_2 and R_2',
R_3 and R_3', R_4 and R_4', R_5 and R_5
', R_6 and R_6', and R_9 and R_9' are not the same. ) (3) The photosensitive layer contains a carrier transporting substance and a carrier generating substance, and the carrier generating substance has the general formula [
A claim which is a squarium compound represented by
1) The electrophotographic photoreceptor described above. (4) A claim in which the photosensitive layer is constituted by a laminate of a carrier generation layer containing a squarium compound represented by the general formula [I] as a carrier generation substance, and a carrier transport layer containing a carrier transport substance. The electrophotographic photoreceptor according to item (1) or (3). (5) The photosensitive layer contains a carrier transporting substance and a carrier generating substance, and the carrier generating substance is of the general formula [I
The claim is a squarium compound represented by
2) The electrophotographic photoreceptor described above. (6) A claim in which the photosensitive layer is constituted by a laminate of a carrier generation layer containing a squarium compound represented by the general formula [II] as a carrier generation substance and a carrier transport layer containing a carrier transport substance. The electrophotographic photoreceptor according to item (2) or (5).