JPH032871A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body having high sensitivity, superior electrostatic chargeability and stable electrophotographic characteristics and hardly causing deterioration due to fatigue even after repeated use by incorporating a specified butadiene compd. CONSTITUTION:A photosensitive layer contg. a butadiene compd. represented by formula I is formed. In the formula I, each of R1 and R3 is aryl or aralkyl which may have a substituent independently, each of R2 and R4 is alkyl, aryl or aralkyl which may have a substituent independently and each of Ar1 and Ar2 is arylene which may have a substituent. The resulting photosensitive body has satisfactory electrostatic chargeability and also has high sensitivity because carriers are hardly trapped. The photosensitive body hardly undergoes optical fatigue.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photoreceptor having a photosensitive layer containing a novel butadiene compound.

Conventional technology In general, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged and exposed to form an electrostatic latent image, which is developed with a developer to make it visible, and the visible image is transferred directly to the photoreceptor. There is a direct method in which the visible image on the photoconductor is transferred onto a transfer material such as paper and the transferred image is fixed on a transfer material such as paper, and a powder image transfer method in which the transferred image is obtained by fixing the transferred image on the photoconductor. transfer the electrostatic latent image onto transfer paper, develop the electrostatic latent image on the transfer paper,
A fixing latent image transfer method is known.

Conventionally, selenium, cadmium sulfide,
Inorganic photoconductive materials such as zinc oxide are known.

Although these photoconductive materials have many advantages, such as less charge dissipation in the dark or the ability to quickly dissipate charge by light irradiation,
It has various drawbacks.

For example, the manufacturing conditions for selenium-based photoreceptors are difficult;
It is expensive to manufacture and requires care when handling because it is susceptible to heat and mechanical shock. With cadmium sulfide photoreceptors and zinc oxide photoreceptors, stable sensitivity cannot be obtained in humid environments, and the dye added as a sensitizer causes charging deterioration due to corona charging and photobleaching due to exposure, so long-term It has the disadvantage that it cannot provide stable characteristics over a long period of time.

On the other hand, various organic photoconductive polymers including polyvinylcarbazole have been proposed, but these polymers are superior to the aforementioned inorganic photoconductive materials in terms of film formability and light weight. However, they are still inferior to inorganic photoconductive materials in terms of sufficient sensitivity, durability, and stability against environmental changes.

In addition, low molecular weight organic photoconductive compounds are preferable in that the physical properties or electrophotographic properties of the film can be controlled by selecting the type of binder used together, the composition ratio, etc. Since it is used in combination with a binder, high compatibility with the binder is required.

Photoreceptors in which these high-molecular-weight and low-molecular-weight organic photoconductive compounds are dispersed in a binder resin have drawbacks such as high residual potential and low sensitivity due to a large number of carrier traps. Therefore, it has been proposed to incorporate a charge transporting material into a photoconductive compound to solve the above-mentioned drawbacks.

Further, a functionally separated photoreceptor has been proposed in which the charge generation function and the charge transport function of the photoconductive function are assigned to separate substances. In such a functionally separated photoreceptor, many organic compounds have been mentioned as charge transport materials used in the charge transport layer, but in practice they have various problems.

For example, 2,5-bis(P-diethylaminophenyl) described in U.S. Pat. No. 3,189.447
1.3.4-Oxadiazole has low compatibility with binders and tends to precipitate crystals. U.S. Patent No. 3,820
Although the diarylalkane derivatives described in , No. 989 have good compatibility with binders, sensitivity changes occur when they are used repeatedly. Also, Unexamined Japanese Patent Publication No. 54-
5. - The hizolazone compound described in Publication No. 143 has relatively good residual potential characteristics, but has the disadvantage of poor charging ability and repeatability.

The reality is that there are almost no low-molecular-weight organic compounds that have practically desirable properties for producing photoreceptors.

Therefore, the present inventor proposed a butadiene compound in JP-A No. 62-10652; however, among them, a compound having an amino group substituted with an aryl or aralkyl group at both ends of the butadiene skeleton has a high sensitivity. It was discovered that the butadiene compound is more excellent in terms of compatibility with resins, and this led to the present invention.

Problems to be Solved by the Invention The present invention contains a butadiene compound that has excellent compatibility with binders and charge transport ability, has high sensitivity and excellent charging ability, has little fatigue deterioration when used repeatedly, and is suitable for electrophotography. The purpose is to provide a photoreceptor with stable characteristics.

The present invention provides a photoreceptor having a photosensitive layer containing a butadiene compound represented by the following formula -1U [N] on a conductive support: [1] [In the formula, R and R3 each independently have a substituent. aryl group or aralkyl group; R2 and R4 are each independently an alkyl group, aryl group, or aralkyl group that may have a substituent; Ar, Ar, each may have a substituent; Regarding 1, which shows a good arylene group.

The photoreceptor of the present invention has a photosensitive layer containing one or more butadiene compounds represented by the general formula [I].

Although the butadiene compound of the present invention is a photoconductive substance, it acts as a charge transport material and can very efficiently transport charge carriers generated by absorbing light.

In the general formula [1] of the present invention, R1 and R3 each independently represent an aryl group such as phenyl or naphthyl; benzyl, 7
It represents an aralkyl group such as enethyl, which groups may have substituents, such as a C1-C2 alkyl group or a 01-C2 methoxy group.

R2 and R4 each independently represent a 01-C4 alkyl group, an aryl group such as phenyl or naphthyl; an aralkyl group such as benzyl or phenethyl; It may have a C2 alkoxy group.

Ar+ and Ar2 each independently represent an arylene group, for example a phenylene group, and the group may have a substituent such as a C1-C2 alkyl group or a C1-C2 methoxy group.

In the present invention, all groups R1 to R4 are preferably aryl groups or aralkyl groups, particularly aryl groups.

Moreover, the substituents of Rr to R4 and Ar, Ar1 are:
From the viewpoint of compatibility with the resin, an alkyl group is preferable.

Preferred specific examples of the butadiene compound represented by the general formula m of the present invention include, for example, those having the following structural formula, but are not limited thereto.

[5] [12] CI+.

[14] CH.

[22] [231 [241 [251 [26] [181 [21] [27] [28] The compound represented by the general formula [I] of the present invention is usually It can be easily synthesized by the following method.

For example, the following general formula [■1; [wherein, R1, R2, A r + have the same meaning as [I]] the following general formula [■]; p.

[In the formula, R3, R6, Ar2 have the same meaning as [I]] and the following general formula [■]: or the following general formula [V]; Ph5PCHzCt (zPPhs ・2X
It can be synthesized by subjecting a phosphorus compound represented by the following formula to a dehydration condensation reaction.

The reaction is generally carried out using an aromatic solvent such as benzene, toluene, or xylene, an alcohol solvent such as methanol or etaryl, an ether solvent such as diethyl ether, 1,2-dimethoxyethane, dioxane, or tetrahydrofuran, dimethyl sulfoxide, dimethylformamide,
Using an aprotic polar solvent such as N-methylpyrrolidone, sodium methoxide, sodium ethoxide, sodium amide, potassium methoxide, potassium-[-
It is carried out using catalysts such as butoxide, sodium hydroxide, potassium hydroxide, etc.

Examples of structures of photoreceptors using the butadiene compound of the present invention are schematically shown in FIGS. 1 to 5.

Figure 1 shows a photoreceptor in which a photosensitive layer (4) containing a photoconductive material (3) and a charge transporting material (2) as a binder is formed on a substrate (1). The butadiene compound of the invention is used.

Figure 2 shows a functionally separated photoreceptor having a charge generation layer (6) and a charge transport layer (5) as photosensitive layers, and the charge transport layer (5) is formed on the surface of the charge generation layer (6). ing.

The butadiene compound of the present invention is blended into the charge transport layer (5).

Figure 3 shows a functionally separated photoreceptor having a charge generation layer (6) and a charge transport layer (5) as in Figure 2, but contrary to the second section, the charge transport layer (5) is A charge generation layer (6) is formed on the surface.

FIG. 4 shows a surface retaining layer (
7), and the photosensitive layer (4) is provided with a charge generation layer (
6) and a functionally separated photoreceptor having a charge transport layer (5).

FIG. 5 shows an intermediate layer (
8), and the intermediate layer (8) can be provided to improve adhesion, coatability, protect the substrate, and improve charge injection from the substrate to the photosensitive layer.

Materials used for the intermediate layer include polymers such as polyimide, polyamide, nitrocellulose, and polyvinyl alcohol, as they are, or in which low-resistance compounds such as tin oxide and indium oxide are dispersed, aluminum oxide, and polyvinyl oxide. A vapor deposited film of silicon, zinc oxide, etc. is suitable, and the film thickness is preferably 1 μm or less.

Materials used for the surface protective layer include acrylic resin,
Suitable materials include polymers such as polyaryl resins, polycarbonate resins, and urethane resins as they are, or those in which low-resistance compounds such as tin oxide and indium oxide are dispersed. Additionally, organic plasma polymerized films can also be used.

The organic plasma polymerized film may contain oxygen, nitrogen, halogen, and atoms of Group Ⅰ and V of the periodic table, as appropriate. Further, the thickness of the surface protective layer is preferably 5 μm or less.

Fabricate a single-layer photoreceptor! In this case, fine particles of the charge generating material may be dispersed in a resin solution or a solution containing a charge transporting compound and a resin, and this may be applied onto a conductive support and dried. The thickness of the photosensitive layer at this time is preferably 3 to 30 μm, preferably 5 to 20 μm. If the amount of the charge generating material used is too small, the sensitivity will be poor, and if it is too large, the charging property will be poor and the mechanical strength of the photosensitive layer will be weakened. The amount ranges from 0.01 to 2 parts by weight, preferably from 0.2 to 1.2 parts by weight.

To produce a laminated photoreceptor, a charge generating material is vacuum deposited on a conductive support, or it is dissolved in a solvent such as amine and applied, or the pigment is coated with a suitable solvent or a binder if necessary. It is obtained by coating and drying a coating liquid prepared by dispersing a resin in a solution, and then coating and drying a solution containing a charge transport material and a binder thereon.

At this time, the thickness of the charge generation layer is preferably 4 μm or less, preferably 2 μm or less, and the charge transport layer has a thickness of 3 to 30 μm.
Preferably it is 5 to 20 μm. The ratio of the charge transport material in the charge transport layer is 0.2 to 1 part by weight of the binder resin.
~2 parts by weight, preferably 0.3 to 1.3 parts by weight.

In addition to the binder resin, the photoreceptor of the present invention contains a plasticizer such as halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutyl phthalate, 0-terphenyl, chloranil, tetracyanoethylene, 2,4.7-dolinitrofluorenone, 5 .Electron-withdrawing sensitizers such as 6-dicyazbenzoquinone, tetracyanoquinodimethane, tetrachlor heptatalic anhydride, 3,5-dinitrobenzoic acid,
Sensitizers such as methyl violet, rhodamine B1 cyanine dye, biryllium salts, thiapyrylium salts, etc. may be used. Additionally, additives known per se such as dispersants, adhesives, antioxidants, ultraviolet absorbers, and anti-curling agents may be added.

As the electrically insulating binder resin used in the present invention, electrically insulating binders such as thermoplastic resins, thermosetting resins, photocuring resins, photoconductive resins, etc., which are known per se, can be used. .

Examples of suitable binder resins include, but are not limited to, saturated polyester resins, polyamide resins, acrylic resins, butyral resins, vinyl acetate resins, phenoxy resins, polyvinyl alcohol resins, ethylene-vinyl acetate resins, Ionically crosslinked olefin copolymer (ionomer), styrene-butadiene block copolymer, polycarbonate H4 resin, aryl resin, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide resin,
Thermoplastic resins such as styrene resin; Thermosetting resins such as epoxy resins, urethane resins, silicone resins, phenol resins, melamine resins, xylene resins, alkyd resins, thermosetting acrylic resins; Ultraviolet curing resins, infrared curing resins, etc. Photocurable resin; photoconductive resin such as polyvinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylpyrrole, etc.

These can be used alone or in combination. These electrically insulating resins are measured individually and have a resistance of lXl0"Ω
- It is desirable to have a volume resistivity of c+++ or more.

It may also be used in combination with other charge transport materials, such as hydrazone compounds and styryl compounds.

Charge-generating materials include bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, quinanthene dyes, cyanine dyes, styryl dyes, biryllium dyes, azo pigments, quinacrid pigments, and indigo dyes. Organic substances such as pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, induthrone pigments, squalium base pigments, azulene pigments, phthalocyanine pigments, selenium, selenium/tellurium, selenium/arsenic, etc. Examples include inorganic materials such as selenium alloys, cadmium sulfide, cadmium selenide, zinc oxide, and amorphous silicon. In addition to these materials, any material can be used as long as it absorbs light and generates charge carriers with an extremely high probability.

As the conductive support used in the photoreceptor of the present invention, a sheet or drum-shaped foil or plate of copper, aluminum, silver, iron, nickel, etc. is used, or a plastic film made of these metals is used. A layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide is coated or deposited on a support such as paper or a plastic film by vacuum deposition or electroless plating. It will be done.

Synthesis Example 3.50 g of a phosphonium salt represented by the following formula; and 2.80 g of an aldehyde compound represented by the following formula; Below C, 1.03 g of potassium tert-butoxide powder was added in small portions. After the addition, the reaction was completed by stirring for 6 hours. The reaction solution was poured into ice water.

After extracting the product with toluene, the toluene was distilled off and 2
．． 1 g of crude product was obtained. This was purified by silica gel chromatography to obtain 1.8 g of crystals (yield: 69
．． 8%). Further recrystallization with ethyl acetate was performed to obtain 1.5 g of yellow crystals.

The elemental analysis values are as follows. (C3a Hs z
N! The present invention will be explained below using Examples. In addition,
In the examples, "parts" represent "parts by weight."

Example 1 Disazo compound represented by the following general formula [AI 0.45
and 0.45 parts of polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) were dispersed together with 50 parts of cyclohexanone using a sand glider.

The resulting bisazo compound dispersion was applied onto a 100 μm thick aluminized mylar using a film applicator.
The coating was applied to a dry film thickness of 0.3 g/m'' and then dried.

A solution of 50 parts of butadiene compound (1) and 50 parts of polycarbonate resin (Panlite -1300, manufactured by Ondai Kasei Co., Ltd.) dissolved in 400 parts of 1,4-dioxane was placed on the charge generation layer thus obtained. The dry film thickness is 16μm
A charge transport layer was formed by coating the film and drying it to form a charge transport layer. In this way, an electrophotographic photoreceptor having a photosensitive layer consisting of two layers is obtained. 6KV
The initial surface potential VO (V) and the exposure amount E1/2 (lux
*5ec), and the decay rate DDR+ (%) of the initial potential when left in the dark for 1 second was measured.

Examples 2 to 4 Same structure as in Example 1, except that butadiene compounds (4), (5), and (6) were used in place of butadiene compound (3) used in Example 1, respectively. A photoreceptor to be used was prepared.

V was applied to the thus obtained photoreceptor in the same manner as in Example 1. , El/2, DDR, were measured.

Example 5 0.45 parts of bisazo compound [B] represented by the following general formula [B], polystyrene resin (molecular weight 40.000)
0.45 part was dispersed with 50 parts of cyclohexanone using a sand glider.

Obtained I: A dispersion of a bisazo compound was applied onto a 100 μm thick aluminized Mylar using a film applicator so that the dry film thickness was 0.3 g/m, and then dried. In this way. A solution of 50 parts of butadiene compound (7) and 50 parts of polyarylate resin (U-100: manufactured by Unitika Co., Ltd.) dissolved in 400 parts of 1,4-dioxane was applied onto the obtained charge generation layer to a dry film thickness of 20 μm. A charge transport layer was formed by coating and drying to form a charge transport layer.

In this way, an electrophotographic photoreceptor having a two-layer photosensitive layer was produced.

Regarding the photoreceptor thus obtained, Vo, El/2, and DDR were measured in the same manner as in Example I.

Examples 6 to 8 Same structure as in Example 5, except that butadiene compounds (8), (9), and (10) were used in place of the butadiene compound (7) used in Example 5, respectively. A photoreceptor to be used was prepared.

V was applied to the thus obtained photoreceptor in the same manner as in Example 1. , El/2, DDR, were measured.

Example 9 0.45 parts of polycyclic quinone pigment [C] represented by the following general formula [C], polycarbonate resin (13 parts in Panlite)
000: manufactured by Ondai Kasei Co., Ltd.) 0.45 parts dichloroethane 5
Disperse with 0 parts in a sand mill.

The obtained polycyclic quinone pigment dispersion was applied onto a 100 μm thick aluminized Mylar using a film applicator so that the dry film thickness was 0.49 parts m'' and then dried. A solution prepared by dissolving 60 parts of butadiene compound (12) and 50 parts of polyarylate resin (U-100 + manufactured by Unitika Co., Ltd.) in 400 parts of 1,4-dioxane was placed on the charge generation layer obtained in the following manner so that the dry film thickness was 18 μm.
A charge transport layer was formed by coating the film and drying it to form a charge transport layer.

In this way, an electrophotographic photoreceptor having a two-layer photosensitive layer was produced, and in the same manner as in Example 1, Vo, E2/
LDDR was measured.

Examples 10 to 11 A photoreceptor with the same structure as in Example 9 was prepared, except that butadiene compounds (13) and (14) were used in place of the butadiene compound (12) used in Example 9. Created.

V was applied to the thus obtained photoreceptor in the same manner as in Example 1. , El/2, DDR, were measured.

Example [2] 0.45 parts of perylene pigment [D] represented by the following general formula [D] and 0.45 parts of butyral resin (BX-1: manufactured by Tsukimizu Kagaku Kogyo Co., Ltd.) were dispersed with 50 parts of dichloroethane in a sand mill. I let it happen.

The obtained perylene pigment dispersion was applied onto a 100 μm thick aluminized mylar using a film applicator.
The coating was applied to a dry film thickness of 0.4 y/m 2 and then dried. 50 parts of butadiene compound (15) and 50 parts of polycarbonate resin (P C-Z: manufactured by Mitsubishi Gas Chemical Co., Ltd.) were placed on the charge generation layer thus obtained.
- A solution dissolved in 400 parts of dioxane has a dry film thickness of 18
A charge transport layer was formed by applying the coating to a thickness of .mu.m.

In this way, an electrophotographic photoreceptor having a two-layer photosensitive layer was prepared, and Vo, El/
2. DDR was measured.

Examples 13 to ■4 Same structure as in Example 12, however,
Photoreceptors were produced using butadiene compounds (17) and (19) in place of the butadiene compound (15) used in Example 12, respectively.

Regarding the photoreceptor thus obtained, Vo, El/2, and DDR were measured in the same manner as in Example 1.

Example 15 50 parts of copper phthalocyanine and 0.2 parts of copper tetranitro phthalocyanine were dissolved in 500 parts of 98% concentrated sulfuric acid with thorough stirring, and this was poured into 5000 parts of water to prepare a photoconductive material of copper phthalocyanine and copper tetranitro phthalocyanine. After the composition was precipitated, it was filtered, washed with water, and dried at 120° C. under reduced pressure.

10 parts of the photoconductive composition thus obtained was added to a thermosetting acrylic resin (Acrytic A405: manufactured by Dainippon Ink Co., Ltd.).
22.5 parts, melamine resin (Super Beckamine J82
0: manufactured by Dainippon Ink Co., Ltd.) and 15 parts of the above-mentioned butadiene compound (1) were placed in a ball mill pot with 100 parts of a mixed solvent in which methyl ethyl ketone and xylene were mixed in equal amounts, and dispersed for 48 hours to make the photosensitive. Adjust the coating liquid,
This coating liquid was applied onto an aluminum substrate and dried to form a photosensitive layer having a thickness of about 15 μm, thereby producing a photoreceptor.

The photoreceptor thus obtained was corona charged in the same manner as in Example 1, except at +6 KV. , E
l/2, DDR, was measured.

Examples 16 to 18 Same method and same configuration as Example 15, but
Photoreceptors were prepared using butadiene compounds (6), (20), and (30) in place of butadiene compound (1) used in Example 15, respectively.

With respect to the thus obtained photoreceptor, V was treated in the same manner as in Example I5. , El/2, DDR, were measured.

Comparative Examples 1 to 4 Same configuration as in Example 15, however,
A photoreceptor was produced in exactly the same manner as in Example 15, except that the following compounds (E), (F), (G), and (H) were used in place of the butadiene compound used in Example 15.

[F] [] Regarding the thus obtained photoreceptor, Vo, E 1/2, and DDR were measured in the same manner as in Example 15.

Comparative Examples 5 to 7 Same structure as in Example 15, but
A photoreceptor was produced in exactly the same manner as in Example 15, except that the following butadiene compounds (1), (J), and (K) were used in place of the butadiene compound (3) used in Example 15.

Body Vo, El/2, Shown all together.

Table 1 shows the measurement results for DDR.

Photoreceptors obtained in Examples 1-18 and Comparative Examples 1 to 7 Table 1 (Continued) As can be seen from Table 1, the photoreceptor of the present invention has sufficient charge retention ability whether it is a laminated type or a single layer type. The dark decay rate is small enough to be used as a photoreceptor, and the sensitivity is also excellent.

Furthermore, a commercially available electrophotographic copying machine (manufactured by Minolta Camera Co., Ltd.: E
P-3502) was conducted on the photoreceptor of Example 15 during positive charging, and even after 5,000 copies, the initial and final images had excellent gradation, no sensitivity change, and were clear. It can be seen that the photoreceptor of the present invention has stable repeatability characteristics.

When the photoreceptor of Comparative Example 7 was subjected to the same photographic test, a decrease in surface potential was observed.

Effects of the Invention The photoreceptor of the present invention has excellent charge transport properties because it contains a butadiene compound represented by the general formula [11].
The initial surface potential is stable, the dark decay rate is sufficiently small, and the material has good charging properties. In addition, there are fewer carrier traps and high sensitivity, and less optical fatigue. In addition, butadiene compounds are particularly effective as charge transport materials for functionally separated photoreceptors.

[Brief explanation of drawings]

FIGS. 1 to 5 are schematic diagrams of photoreceptors according to the present invention, and FIGS. 1, 4, and 5 are dispersion type photoreceptors in which a photosensitive layer is laminated on a conductive support. FIGS. 2 and 3 show the structure of a functionally dispersed photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support. l... Conductive support, 2... Charge transport material, 3...
- Photoconductive material, 4... Photosensitive layer, 5... Charge transport layer, 6... Photoconductive, 7... Surface holding layer, 8.
...middle class. Figure 1 Figure 2 Figure 3 Figure 4 Patent applicant Minolta Camera Co., Ltd. Representative Patent attorney Haka Aoyama Figure 5

Claims (1)

[Claims] 1. A photoreceptor having a photosensitive layer containing a butadiene compound represented by the following general formula [I] on a conductive support: ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] [ In the formula, R_1 and R_3 are each independently an aryl group or an aralkyl group which may have a substituent; R_2,
R_4 is an alkyl group, aryl group or aralkyl group that may each independently have a substituent; Ar_1, Ar
_2 each represents an arylene group which may have a substituent].