JPH05281766A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having high sensitivity with small residual potential and excellent durability and showing no change in these characteristics even for repeated use. CONSTITUTION:This electrophotographic sensitive body has a photosensitive layer containing a bisazo compd. expressed by formula I or II formed on a conductive supporting body. In formula, R1-R4 are hydrogen atoms, halogen atoms, lower alkyl groups, or lower alkoxy groups, A and B are coupler residues containing hyhdroxyl groups having coupling ability, and A and B may be same or different.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive member, and more particularly to an electrophotographic photosensitive member having a photosensitive layer containing a specific bisazo compound.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide or silicon as a main component has been widely used. However, these are not always satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability and the like. Further, some inorganic photoconductors have a problem in disposal because they contain substances harmful to the human body.

In order to overcome the drawbacks of these inorganic photoconductors, research and development of organic photoconductors having a photosensitive layer containing various organic photoconductive compounds as main components have been actively conducted in recent years. In particular, the function-separated type photoconductor in which the carrier generation function and the carrier transport function are shared by different substances can select each material from a wide range, and a photoconductor having arbitrary performance can be prepared relatively easily. Many studies have been carried out because of the possibility, and some have been put to practical use. For example, U.S. Pat. No. 3,871,882 uses a perylene derivative as a carrier generating layer and an oxadiazole derivative as a carrier transporting layer, and JP-A-55-84943 discloses that a carrier generating substance is a distyrylbenzene bisazo compound and a carrier transporting substance. Those using hydrazone compounds are known.

[0004]

However, such photoreceptors are not always satisfactory in sensitivity and durability, and most of them have been used mainly for low speed machines having low sensitivity and printing durability. .. Further, there has been a demand for the development of a highly sensitive and durable photoconductor that can be used in high-speed machines.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photosensitive member having high sensitivity, a small residual potential, and excellent durability which does not change their characteristics even after repeated use.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above objects, the present inventors have found that a specific bisazo compound can act as an excellent active ingredient of an electrophotographic photoreceptor, The present invention has been completed. That is, the above object of the present invention can be achieved by using an electrophotographic photosensitive member having a photosensitive layer containing a bisazo compound represented by the following general formula [1] or [2] on a conductive support. it can.

[0007]

[Chemical 3]

R ₁ and R _{2 in} the general formula [1] and R ₃ and R ₄ in the general formula [2] are each a hydrogen atom, a halogen atom,
It represents a lower alkyl group or a lower alkoxy group, and A and B in each general formula represent a coupler residue containing a hydroxyl group having a coupling ability, and A and B may be the same or different.

The alkyl group of R ₁ , R ₂ , R ₃ and R ₄ is preferably an alkyl group having 1 to 4 carbon atoms, for example, methyl group, ethyl group, isopropyl group, t-butyl group, trifluoromethyl group. Etc. can be mentioned.

The alkoxy group represented by R ₁ , R ₂ , R ₃ and R ₄ is preferably an alkoxy group having 1 to 4 carbon atoms, for example, a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group, Examples thereof include 2-chloroethoxy group. The halogen atom of R ₁ , R ₂ , R ₃ and R ₄ is Cl,
Br, I, and F can be mentioned as specific examples.

The coupler residue containing a hydroxyl group having a coupling ability in the general formulas [1] and [2] is selected from the coupler components represented by the following general formulas [3] to [5]. Is desirable.

[0012]

[Chemical 4]

In the above general formula [3], X represents a residue which is condensed with a benzene ring to form a polycyclic aromatic ring or a heterocycle, and R ₅ is a hydrogen atom or an alkyl group which may have a substituent. , Aralkyl group, and heterocyclic group.

In the general formula [4], R ₆ represents an optionally substituted alkyl group, aralkyl group, aryl group or heterocyclic group.

Further, in the above general formula [5], Y represents a divalent group of an aromatic hydrocarbon or a divalent group forming a heterocycle with a nitrogen atom.

Specific examples of the polycyclic aromatic ring and hetero ring formed by the condensation of X with the benzene ring in the general formula [3] include naphthalene ring, anthracene ring, benzocarbazole ring and dibenzofuran ring. be able to. Examples of the alkyl group of R ₅ include methyl,
Examples thereof include substituted and unsubstituted alkyl groups such as ethyl, propyl, butyl, 2-hydroxyethyl, 2-chloroethyl and the like. Examples of the aryl group of R ₅ include groups such as phenyl and naphthyl. Further, examples of the aralkyl group of R ₅ include groups such as benzyl. Further, as the heterocyclic group of R ₃ ,
Examples include groups such as pyridyl, quinolyl, thiazolyl and furyl.

Further, the aryl group, aralkyl group and heterocyclic group of R ₅ may have the following substituents. Substituted or unsubstituted alkyl groups such as methyl, ethyl and trifluoromethyl, halogen atoms of F, C1, Br and I, alkoxy groups such as methoxy and ethoxy, acetyl groups such as acetyl and benzoyl, alkylthio such as methylthio and ethylthio. Substituted amino groups such as groups, nitro groups, cyano groups, dimethylamino, diethylamino and the like.

An alkyl group represented by R _{6 in} the general formula [4],
Specific examples of the aryl group, aralkyl group and heterocyclic group are similar to those of R ₅ in the general formula [3].

Specific examples of Y in the general formula [5] include
Mention may be made of groups such as o-phenylene and o-naphthylene. Further, these divalent groups may have a substituent such as those mentioned above as the substituent for R ₅ in the general formula [3].

Next, specific examples of the viaszo compound represented by the above general formula [1] or [2] of the present invention will be described, but the viaszo compound of the present invention is not limited thereto.

[0021]

[Chemical 5]

[0022]

[Chemical 6]

[0023]

[Chemical 7]

[0024]

[Chemical 8]

[0025]

[Chemical 9]

[0026]

[Chemical 10]

[0027]

[Chemical 11]

[0028]

[Chemical formula 12]

[0029]

[Chemical 13]

[0030]

[Chemical 14]

[0031]

[Chemical 15]

[0032]

[Chemical 16]

[0033]

[Chemical 17]

[0034]

[Chemical 18]

[0035]

[Chemical 19]

[0036]

[Chemical 20]

[0037]

[Chemical 21]

[0038]

[Chemical formula 22]

The biaszo compounds represented by the above general formulas [1] and [2] of the present invention can be synthesized by a known method.

Synthesis Example 1 (Synthesis of Exemplified Compound No. 3) 2.38 g (0.01 mol) of 2,7-diaminocyclopenta [l, m, n] -4-oxaphenanthren-5-one was added to 10 ml of hydrochloric acid, 20 ml of water
Dispersed in, and kept at 5 ℃ or less, sodium nitrite 1.4
A solution of g (0.02 mol) in 5 ml of water was added dropwise. After continuing stirring at the same temperature for another hour, insoluble materials were removed by filtration, and the filtrate was added with ammonium hexafluorophosphate (4.6 g) in water (50 g).
A solution dissolved in ml was added. The precipitated tetrazonium salt was collected by filtration and N, N-dimethylformamide (DMF) 100 ml
Dissolved in. 2-hydroxy-3-while keeping below 5 ℃
A solution of 5.94 g of naphthoic acid-3'-chloroanilide in 200 ml of DMF was added dropwise. While keeping the temperature below 5 ° C, add 6 g (0.04 mol) of triethanolamine to DMF30.
What was melt | dissolved in ml was dripped, and it stirred at 5 degreeC or less for 1 hour, and room temperature for 4 hours. After the reaction, the precipitated crystals were collected by filtration, washed with DMF, washed with water and dried to obtain 5.3 g of the desired product.

In the elemental analysis, the measured value (C = 67.8%, H = 3.25%, N = 9.83%) of this compound was the theoretical value (C = 67.4%, H = 3.27%, N = 9.82%). Since there is a good agreement, the target compound No. It was confirmed to be 3.

Synthesis Example 2 (Synthesis of Exemplified Compound No. 62) 2.52 g (0.01 mol) of 2,7-diaminocyclopenta [l, m, n] -4-oxaphenanthrene-5,10-dione was added to hydrochloric acid. Ten
A dispersion of 1.4 g (0.02 mol) of sodium nitrite in 5 ml of water was added dropwise while the mixture was dispersed in 20 ml of water and 20 ml of water. After stirring at the same temperature for 1 hour, insoluble matter was removed by filtration, and 4.6 g of ammonium hexafluorophosphate was added to the filtrate.
Was dissolved in 50 ml of water and added. The precipitated tetrazonium salt was collected by filtration, and N, N-dimethylformamide (DMF)
It was dissolved in 100 ml. 2-hydroxy-3-naphthoic acid-3'-trifluoromethylanilide 6.62 while keeping the temperature below 5 ° C
g (0.02 mol) was dissolved in 200 ml DMF.

While keeping the temperature below 5 ° C, 6 g (0.04 mol) of triethanolamine dissolved in 30 ml of DMF was added dropwise, and the mixture was stirred at 5 ° C or less for 1 hour and at room temperature for 4 hours. After the reaction, the precipitated crystals were collected by filtration, washed with DMF, washed with water and dried to obtain 6.4 g of the desired product.

In the elemental analysis, the measured value (C = 63.9%, H = 2.75%, N = 8.99%) of this compound was the theoretical value (C = 64.1%, H = 2.78%, N = 8.97%). Since there is a good agreement, the target compound No. It was confirmed to be 62.

In the same manner as in the above-mentioned synthetic examples, the other compounds of the present invention were also prepared into tetrazo compounds using the corresponding substituted and unsubstituted diamino compounds, and then 2-hydroxy-3-naphthoic acid-substituted and unsubstituted anilides. It can be made by reacting a phenolic coupler such as.

The bisazo compound of the present invention has excellent photoconductivity, and the electrophotographic photoreceptor of the present invention can be produced by providing a photosensitive layer having the photoconductive layer dispersed in a binder on a conductive support. it can. The bisazo compound of the present invention is
By utilizing this excellent carrier-generating ability as a carrier-generating substance and by using together with this a carrier-transporting substance capable of effectively acting, a so-called functional dispersion type photoreceptor can be obtained.

The function-separated type photoconductor may be a mixed dispersion type of the above substances, but a carrier generation layer containing a carrier generation substance comprising the bisazo compound of the present invention,
It is preferable to use a laminated type photoreceptor in which a carrier transport layer is laminated.

The electrophotographic photosensitive member of the present invention is, for example, the first
As shown in the figure, a carrier generating layer 2 containing a carrier generating substance and a binder resin is used as a lower layer on a support 1 (a conductive support or a sheet on which a conductive layer is provided), and a carrier transporting substance and a binder resin. A function-separated type laminated photoreceptor having a carrier transport layer 3 as an upper layer, and a laminated photoreceptor having a carrier transport layer 3 as a lower layer and a carrier generation layer 2 as an upper layer on a support 1 as shown in FIG. , And a single-layer photosensitive body containing a carrier-generating substance, a carrier-transporting substance, and a binder resin on the support 1 as shown in FIG. In any of the layer configurations, FIGS.
As shown in the figure, a subbing layer (intermediate layer) having a barrier function and adhesiveness may be provided between the support and the photosensitive layer, and as shown in FIG. 7 to FIG. A protective layer may be provided.

In the present invention, the carrier generating layer is typically a dispersion prepared by dispersing the above-mentioned bisazo compound of the present invention in a suitable dispersion medium together with a suitable binder resin, for example, by dib coating, spray coating, blade coating, roll. It can be provided by a method of coating on a support or an undercoat layer or a carrier transport layer by coating and drying. Further, for the dispersion of the bisazo compound of the present invention, a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor and the like can be mentioned.

Examples of the binder resin that can be used in the photosensitive layer, the protective layer and the subbing layer include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin and phenol resin. , Polyester resin, alkyd resin, polycarbonate resin, silicone resin,
Examples include melamine resins, copolymer resins containing two or more of repeating units of these resins, and insulating resins thereof, as well as polymer organic semiconductors such as poly-N-vinylcarbazole.

Next, as a conductive support for supporting the photosensitive layer, a metal plate of aluminum, nickel or the like, a metal drum or a metal foil laminated, or a plastic film deposited with aluminum, tin oxide, indium oxide or the like is deposited. Alternatively, a paper or plastic film or drum coated with a conductive substance can be used.

Examples of the dispersion medium of the bisazo compound of the present invention include hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and 1,2-dichloroethane; ketones such as methyl ethyl ketone and cyclohexanone; ethyl acetate; Esters such as butyl acetate; alcohols such as methanol, ethanol, propanol, butanol, methylcellosolve, ethylcellosolve and derivatives thereof; ethers such as tetrahydrofuran and 1,4-dioxane; amines such as pyridine and diethylamine; N,
One or more nitrogen compounds such as amides such as N-dimethylformamide, other fatty acids and phenols, sulfur such as carbon disulfide and triethyl phosphate, phosphorus compounds and the like can be used.

When the photoreceptor of the present invention has a laminated structure, the weight ratio of the binder to the carrier-generating substance in the carrier-generating layer is 1 to 1.
It is 10: 1 to 50.

If the content of the carrier-generating substance is lower than this range, the sensitivity is low and the residual potential is increased, and if it is higher than this range, the dark decay and the receptive potential are lowered.

The thickness of the carrier generating layer formed as described above is preferably 0.01 to 10 μm, particularly preferably 0.1.
~ 5 μm.

The carrier transporting material used in the present invention is not particularly limited, but it is excellent in the ability to transport holes generated at the time of light irradiation to the support side and is suitable for combination with the bisazo compound of the present invention. It is preferably used.
Preferred examples of the carrier transport material include those represented by the following general formulas (A) and (B).

[0057]

[Chemical formula 23]

However, Ar ₁ , Ar ₂ and Ar ₄ each represent a substituted or unsubstituted aryl group, Ar ₃ represents a substituted or unsubstituted arylene group, and R represents a hydrogen atom or an alkyl group or an aryl group substituted. , Represents an unsubstituted 2 group.

Specific examples of the compound represented by formula (A) are described in detail in JP-A-58-65440 and JP-A-58-198043.

Specific examples of the compound represented by formula (B) are described in detail in JP-A-60-175052 and JP-A-1-93746.

Other preferable carrier-transporting substances of the present invention include hydrazone compounds, styryl compounds, aromatic amine compounds, and polymeric organic semiconductors such as polyvinylcarbazole.

The carrier-transporting layer can be formed by applying a carrier-transporting substance alone or dissolving and dispersing the carrier-transporting substance in a suitable dispersion medium together with the above-mentioned binder resin, and drying. As the dispersion medium used, the dispersion medium used in the dispersion of the carrier generating substance can be used.

The carrier transport material is preferably 20 to 200 parts by weight per 100 parts by weight of the binder resin in the carrier transport layer.
It is particularly preferably 30 to 150 parts by weight. The thickness of the formed carrier transport layer is preferably 5 to 30 μm.

In the case of a single-layer functionally separated type electrophotographic photoreceptor using the bisazo compound of the present invention, the ratio of the binder: the bisazo compound of the present invention: the carrier transporting substance is 1 to 10.
0: 1 to 500: 1 to 500 is preferable, the thickness of the photosensitive layer formed is preferably 5 to 50 μm, particularly preferably 5 to 30 μm.
m.

In the photosensitive layer of the present invention, the following antioxidants may be added for the purpose of preventing ozone deterioration.

(1) Hindered phenols (2) Hindered amines (3) Paraphenylenediamines (4) Hydroquinones (5) Organophosphorus compounds These compounds are used as antioxidants for rubber, plastics, oils and fats. It is known and commercially available.

In the present invention, the photosensitive layer may contain an electron-accepting substance for the purpose of improving sensitivity, reducing residual potential and reducing fatigue during repeated use. The addition ratio of such an electron accepting substance is 100: 0.01 to 100, preferably 100: 0.1 to 50, in terms of the weight ratio of all carrier generating substances: electron accepting substances.

Further, organic amines can be added to the photosensitive layer of the present invention for the purpose of improving the carrier generating function of the carrier generating substance, and it is particularly preferable to add a secondary amine. The amount of the organic amine added is 1 times or less, preferably 0.2 times to 0.005 times, the number of moles of the carrier generating substance with respect to the carrier generating substance.

Further, the photoreceptor of the present invention may further contain an ultraviolet absorber or a dye for color sensitivity correction for the purpose of protecting the photosensitive layer, if necessary.

[0070]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereby.

Examples 1 to 30 Vinyl chloride-vinyl acetate-on a conductive support formed by laminating an aluminum foil on a polyester film.
A 0.05 μm thick intermediate layer made of maleic anhydride copolymer “S-REC MF-10” (manufactured by Sekisui Chemical Co., Ltd.) was provided, and the exemplified compound No. 1,3,4,6,8,9,14,1
8, 21, 24, 27, 30, 36, 47, 53, 54, 56, 57, 60, 6
2,66,70,73,80,82,86,94,96,101,105 2g each and polyvinyl butyral resin "ESREC BH
-3 "(manufactured by Sekisui Chemical Co., Ltd.) and tetrahydrofuran (110 ml) were added, and the mixture was dispersed for 12 hours with a ball mill. Apply this dispersion so that the film thickness when dried will be 0.5 μm.
As a carrier generating layer, and further thereon, as a carrier transporting layer, 6 g of a carrier generating substance (K-1) having the following structural formula and 10 g of a polycarbonate resin "Iupilon Z-200" (manufactured by Mitsubishi Gas Chemical Co., Inc.) 1,2- A solution dissolved in 80 ml of dichloroethane was applied so as to have a film thickness after drying of 20 μm to form a carrier transport layer, and photoconductors 1 to 30 of the present invention were prepared.

[0072]

[Chemical formula 24]

The photosensitive member obtained as described above is manufactured by
The following characteristics were evaluated using an EPA-8100 type electrostatic paper testing machine manufactured by Kawaguchi Denki Seisakusho. After charging for 5 seconds with a charged voltage of -6 KV, the surface potential (V0) at that time was measured after standing for 5 seconds. Then, the exposure amount (half-exposure amount) E1 / 2 required for radiating the halogen lamp light to the surface of the photosensitive member so that the illuminance on the surface becomes 10 lux, and the residual potential after irradiation for 10 seconds ( Vr) was calculated. The results are shown in Table 1.

Comparative Example (1) The following bisazo compound (G-1) was used as a carrier generating substance.
A comparative photoreceptor was prepared in the same manner as in Example 1 except that was used.

[0075]

[Chemical 25]

When this comparative photoreceptor was measured in the same manner as in Example 1, the results shown in Table 1 were obtained.

As is clear from the above results, the photoconductor of the present invention is extremely excellent in sensitivity as compared with the comparative photoconductor.

[0078]

[Table 1]

Examples 31 and 32 Vinyl chloride was applied to the surface of an aluminum drum having a diameter of 60 mm.
Vinyl acetate-maleic anhydride copolymer "ESREC MF
-10 "(manufactured by Sekisui Chemical Co., Ltd.), and an intermediate layer having a thickness of 0.05 μm is provided, and the exemplified compound No. 2 g of 3,62 and 2 g of polyvinyl butyral resin "ESREC BH-3" (manufactured by Sekisui Chemical Co., Ltd.) were mixed in 100 ml of tetrahydrofuran, and the dispersion liquid dispersed for 24 hours with a ball mill disperser had a film thickness after drying of 0.6 μm. To form a carrier generation layer.

Furthermore, a carrier transporting material (K-
1) 30g and polycarbonate resin "Iupilon Z-20"
0 ”(manufactured by Mitsubishi Gas Chemical Co., Inc.) 50 g and 1,2-dichloroethane 4
It was dissolved in 00 ml and coated so that the film thickness after drying would be 20 μm to form a carrier transport layer, and photoconductors 31 and 32 were prepared.

The photoconductors 31 and 32 thus prepared were mounted on a modified machine of the electrophotographic copying machine "U-Bix1550MR" (manufactured by Konica), and when the image was copied, the contrast was high and the original image was faithful. A clear copy image was obtained. In addition, when the durability of this machine was tested repeatedly in an environment test room under high temperature and high humidity (33 ° C; 80%), a clear and high-contrast copy image was obtained even after 50,000 cycles.

Comparative Example (2) A drum-shaped comparative photoreceptor was prepared in the same manner as in Example 31, except that the exemplifying compound in Example 31 was replaced with the bisazo compound represented by the following structural formula (G-2). When prepared and evaluated in the same manner as in Example 31, the copied image was evaluated, and in repeated durability under high temperature and high humidity, the contrast decreased after about 30,000 times and only an image with a lot of fog was obtained.

[0083]

[Chemical formula 26]

Examples 33 to 36 Vinyl chloride-vinyl acetate-on a conductive support formed by laminating an aluminum foil on a polyester film.
A 0.05 μm thick intermediate layer made of maleic anhydride copolymer “S-REC MF-10” (manufactured by Sekisui Chemical Co., Ltd.) was provided, and 6 g of the following structural formula (K-2) as a carrier transporting substance and a polycarbonate were provided thereon. Resin "Panlite L-125
A solution prepared by dissolving 10 g of "0" in 80 ml of 1,2-dichloroethane was applied so that the film thickness after drying would be 15 μm, to form a carrier transport layer.

[0085]

[Chemical 27]

Further, each of the exemplified compounds No. 3,21,
62 g of 73, 2 g, 1.5 g of the carrier-transporting substance, and 2 g of polycarbonate resin "Panlite L-1250" are 1,2-
In addition to 30 ml of dichloroethane, a liquid dispersed by a ball mill was applied for 24 hours, and a carrier generating layer having a film thickness after drying of 4 μm was provided. Created 33-36. Measurements were made in the same manner as in Example 1 except that the charging polarity of these photoconductors was positively charged, and the results shown in Table 2 were obtained.

[0087]

[Table 2]

As is clear from the results of the above Examples and Comparative Examples, the photoconductor of the present invention is more stable and stable than the photoconductor for comparison.
It is remarkably excellent in sensitivity and durability.

[0089]

The electrophotographic photosensitive member having the bisazo compound of the present invention has high sensitivity and good color sensitivity, and in particular, even when repeatedly used, the sensitivity, charging property and residual potential do not fluctuate and durability is long. It's very good. In addition to electrophotographic plain paper copiers, laser printers, L
The photoconductor is also suitable as a photoconductor for a printer such as an ED printer.

[Brief description of drawings]

1 to 9 are sectional views showing the layer structure of the photoconductor of the present invention.

[Explanation of symbols]

1: Conductive support 2: Carrier generation layer 3: Carrier transport layer 4: Photosensitive layer 5: Intermediate layer 6: Protective layer

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[Procedure amendment]

[Submission date] April 27, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

Claims (2)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer containing a bisazo compound represented by the following general formula [1] on a conductive support. [Chemical 1] (Wherein R ₁ and R ₂ each represent a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, A and B represent a coupler residue containing a hydroxyl group having a coupling ability,
A and B may be the same or different. ) 2. An electrophotographic photoreceptor having a photosensitive layer containing a bisazo compound represented by the following general formula [2] on a conductive support. [Chemical 2] (In the formula, R ₃ and R ₄ each represent a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, A and B represent a coupler residue containing a hydroxyl group having a coupling ability,
A and B may be the same or different. )