JPS60233656A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To ensure an electrophotographic characteristics good in both positive and negative triboelectrifiability by forming on a conductive layer a photosensitive layer contg. an electrostatic charge generating material of at least one of gamma, gamma', eta, and eta' type metal-free phthalocyanines, and a charge transfer material. CONSTITUTION:As the charge generating material, at least one of gamma, gamma', eta, and eta' type metal-free phthalocyanines is used and as the charge transfer material, a dielectric body of a polymer, such as polyvinylpyrene, or a low mol.wt. compd., such as fluorene, is used. As a binder, insulating resins having film-forming property in a normal state, and resins capable of being hardened with heat and/ or light and forming a film are used. The photosensitive layer is formed by mixing said charge generating material, said charge transfer material, said binder, additives, such as a dispersing aid and a plasticizer, with a solvent, such as ketones and ethers, dissolving them, coating the conductive layer, and drying them. As a result, an electrophotographic sensitive body triboelectrifiable to both positive and negative polarities can be obtained by forming a single photosensitive layer on the conductive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrophotographic photoreceptor in which the photoreceptor layer is a layered type and has both positive and negative chargeability.

(Prior Art) Conventionally, in electrophotographic photoreceptors that use photoconductive substances as photosensitive materials, selenium and zinc oxide have been used.

Inorganic photoconductive materials such as titanium oxide and cadmium sulfide have been mainly used.

However, many of these are highly toxic.

There are also problems with the method of disposal.

On the other hand, photoreceptors using organic photoconductive compounds.

It has been widely studied recently because it is generally less toxic than the use of inorganic photoconductive materials, and is advantageous in terms of flexibility, light weight, and cost.

When these photoreceptors are applied to an electrophotographic device using the Carlson method, a transparent layer is formed on the surface of the photoreceptor.
Next, the image is developed using toner charged with opposite signs, and the toner image is transferred and fixed onto another substrate 1, such as paper, to obtain a copy.

In recent years, composite photoreceptors using organic photoconductive compounds are expected to be used as electrophotographic photoreceptors because they can significantly improve the low sensitivity that was a drawback of conventional organic photoreceptors. I'm here.

Preferred composite electrophotographic photoreceptors are disclosed in Japanese Patent Application Laid-Open No. 58-182639 and the like.

As described above, conventional electrophotographic photoreceptors, including composite types, using organic photoconductive compounds are usually used with the surface of the photoreceptor negatively charged. However, when a negative corona is discharged, a large amount of ozone is generated.

Furthermore, since the surface of the photoreceptor is non-uniformly charged, a positively charged photoreceptor is desired. Furthermore, if a photoreceptor has electrophotographic properties that are the same whether it is negatively charged or positively charged, it is expected that its applications, such as color printers, will be greatly expanded.

(Purpose of the invention) The present invention is intended to solve these problems.

The present invention provides an electrophotographic photoreceptor that can be charged both positively and negatively.

(Structure of the Invention) The present invention provides a single-layer photosensitive layer comprising a conductive layer and a photosensitive layer containing at least one charge-generating material and a charge-transporting material among τ, τ', η, and η' type gold metal phthalocyanines. The present invention relates to an electrophotographic photoreceptor that can be charged both positively and negatively.

τ, τ′ which are charge generating materials used in the present invention
, η and η′ type metal phthalocyanine 9% open 58-1
Publication No. 82640 and European Patent Publication No. 92255
This is what is stated in the No.

The τ-type metal-free phthalocyanine has a Bragg angle (2θ±0
．． 2 degrees) is 7.6, 9.2, 16.8, 17.4°20
．． It has an X-ray diffraction pattern with characteristic peaks at 4 and 20.9, and especially has an infrared absorption spectrum of 700 to
Between 760 and 12 countries, 751 and 12 countries have four strongest absorption bands, and between 1320 and 1340 an-1, two absorption bands of almost the same strength are found at 3288 ± 3 cm. It is preferable to use a material that has a certain level of absorption.

The τ' type metal-free phthalocyanine/bragg angle (2θ±
0.2 degree) is 7.5, 9.1, 16.8, 17.
It has an X-ray diffraction pattern with strong peaks at 3°20.3, 20.8, 21.4 and 27.4, and an infrared absorption spectrum of 753 (±2
)am-' is the strongest four absorption bands from 1320 to 134
Two absorption bands of approximately the same intensity between 0 cIn-1,
It is desirable to have a characteristic absorption at 3297±3 cm-'.

η and η' type gold metal 7 thalocyanine, 100 parts by weight of metal-free phthalocyanine and -t- metal-free phthalocyanine containing a substituent on the benzene nucleus, phthalocyanine nitrogen isoconstructor or metal which may have a substituent on the benzene nucleus Crystalline mixture of one or more phthalocyanines and up to 50 parts by weight of two or more phthalocyanines.

There are two types of η and η' types each.

The η-type metal phthalocyanine has an infrared absorption spectrum with four absorption bands with the strongest intensity between 700 and 760 cm-1 and two absorption bands with almost the same intensity between 1320 and 1340 an-''. The absorption band is 3285±5cm''
1 has a characteristic absorption. One type of η-type metal phthalocyanine has a Bragg angle K (2θ±0.2 degrees),
? , 6.9.2.16.8.17.4 and 28.5, and the other species are 7.6.9.2.16.8. 17.421.
It has an X-ray diffraction pattern with characteristic peaks at 5 and 27.5.

η'-type gold metal phthalocyanine, infrared absorption spectrum is between 700 and 760 cm-', 753-11 cm-'
The four strongest absorption bands are 1320 to 1340CIn
-', two absorption bands of almost the same intensity are added to 3297 and 5c.
The η'-type gold metal phthalocyanine has a Bragg angle (2θ±2 degrees) of 7.5.
, 9.1, 16.8, 17.3, 20.3, 20.8°, has an X-ray diffraction pattern with characteristic peaks at 21.4 and 27.4, and the other kind is 7. 5,9.1゜16
．． 8,17°3,20.3,20.8,21.4,22
．． It has an X-ray diffraction pattern with characteristic peaks at 1°27.4 and 28.5°.

A τ and τ′ type gold metal phthalocyanine 9, such as an α type metal-free phthalocyanine, is dispersed in a liquid dispersion medium.

50-180°C, preferably 60-180°C in the presence of a grinding aid
It can be produced by milling with stirring or mechanical strain at a temperature of 130° C. for a time sufficient to effect crystal transformation.

η and η' type gold metal phthalocyanine 9 For example, 100 parts by weight of α type metal-free phthalocyanine and metal-free phthalocyanine having a substituent on the benzene nucleus, phthalocyanine nitrogen which may have a substituent on the benzene nucleus such as a porphine compound 50 parts by weight or less, preferably 0.1 to 30 parts by weight of the same structure or metal phthalocyanine are dispersed in a liquid dispersion medium, and the mixture is heated at 30 to 220°C, preferably 60°C in the presence of a grinding aid.
It can be produced by milling at 0 to 130° C. with stirring or mechanical strain for a time sufficient to convert the crystals.

Charge transporting substances that are the main components of the charge transport layer include polymer compounds such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylindoquinoxaline, polyvinylbenzothiophene, and polyvinylanthracene. , polyvinylacridine.

Polyvinylpyrazoline etc. are low molecular weight compounds such as fluorene, fluorenone, 2+7-sinitro-9-fluorenone, 2,4.7-dolinitro-9-fluorenone, 4H-indeno(1,2,6)thiophen-4-one, 3.7-sinitrodibenzothiophene-5-oxide, 1-bromopyrene, 2-phenylpyrene, carbazole, 3-phenylcarbazole, 2-phenylindole, 2-phenylnaphthalene, oxadiazole,
Oxatriazole, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)hylasoline, 2-phenyl-47(4-diethylaminophenyl)-5-phenyloxazole, triphenylamine, imidazole, chrysene , tetrafen,
Examples include acridene and derivatives thereof.

In addition to the charge-generating material and charge-transporting material described above, a binder may be mixed into the single-layer electrophotographic photoreceptor according to the present invention. Examples of the binder include silicone resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, polystyrene, acrylic resin, and methacrylic resin. Furthermore, thermosetting and/or photocuring resins that are crosslinked by heat and/or light can also be used. In any case, there are no particular limitations as long as the resin is insulative and has a film-forming ability in a normal state, or a resin that can be cured by heat and/or light to form a film.

The blending ratio of the charge transport material and the binder is 10 parts of the charge transport material.
The binder is preferably 80 to 450 parts by weight, particularly preferably 100 to 300 parts by weight. If the binder is too small, the film strength of the photoreceptor will be poor, and if the binder is too large, the electrophotographic properties will be degraded.

The charge generating material is preferably present in a photosensitive layer forming material containing a charge transporting material, a binder, and various additives described below.
1 to 15% by weight, particularly preferably 0.5 to 5% by weight are used. If the amount of τ, τ', η or η' type gold metal phthalocyanine is too small, the electrophotographic properties will be poor, and if it is too large, the charging property will be reduced.

The single-layer electrophotographic photoreceptor according to the present invention further includes a dispersion aid,
Additives such as plasticizers, flow agents, pinhole inhibitors, etc. can be used. Dispersing aids include aliphatic polycarboxylic acids, anionic surfactants, long-chain polyaminoamide phosphates, etc. Plasticizers include halogenated paraffins, dimethylnaphthalene, dibutyl phthalate, etc., and fluidity imparting agents. Examples include Modaflow (manufactured by Monsando Chemical Co.), Acronal 4F (manufactured by Bass 7), etc. Pinhole inhibitors include benzoin, dimethyl terephthalate, etc. 9 Dispersion aids have a
The amount of other additives is not more than 5 parts by weight based on the binder, and is appropriately selected and used.

In the present invention, the conductive layer is a conductive material such as paper or plastic film subjected to conductivity treatment, a plastic film laminated with metal foil such as aluminum, or a metal plate.

In the single-layer electrophotographic photoreceptor according to the present invention, a photosensitive layer having a thickness of preferably 5 to 50 μm, particularly preferably 8 to 20 μm is formed on the conductive layer. If the thickness is less than 5 μm, the initial potential tends to be low, and if it exceeds 50 μm, the sensitivity tends to decrease.

To form the photosensitive layer, the charge generating material, charge transporting material, binder, and appropriately selected additives according to the present invention, a ketone solvent such as a7tone or methyl ethyl ketone, an ether solvent such as tetrahydrofuran or dioxane, Methylene chloride, 1,1,2-)lichloroethane, 1,1,2,2-
A liquid obtained by mixing and uniformly dispersing or dissolving a solvent such as a halogenated solvent such as tetrachloroethane, or an aromatic solvent such as toluene or xylene, or a charge transport material, a binder, and appropriately selected additives in the above solvent. Once dissolved, the charge generating material is uniformly dispersed or dissolved in this solution.

This can be done by coating the conductive layer and drying it.

The electrophotographic photoreceptor according to the present invention may have a thin adhesive layer or barrier layer immediately above the conductive layer, and a protective layer on the surface of the photoreceptor.

The copying method using the electrophotographic photoreceptor according to the present invention may adopt a method in which the surface of the electrophotographic photoreceptor is charged and exposed to light, developed, and the image is transferred and fixed onto the paper.

Next, Examples and Comparative Examples related to the present invention will be shown.

Each material used in the examples below is listed below. Values within 0 indicate abbreviations.

(1) Charge generating material τ-type metal-free phthalocyanine (τ-H2PC) (manufactured by Toyo Ink ■, having the black angle and infrared absorption spectrum explained above) (2) Charge transporting material o2-(p-diethylamino)phenyl -4-(p-dimethylamino)phenyl-5-(o-chloro)phenyl-1,3-oxazole(OXZ)01-phenyl-3
-(p-diethylamino)styryl-5-(p-diethylamino)phenylpyrazoline (PYZ) (3) Binder O Acrylic resin: Elvacite 2045 [Dupont] 0 Polyester resin: Byron 200 (Toyobo ■
] O polycarbonate resin: Corpilon 82000 (
Mitsubishi Gas Chemical ■] O silicone varnish: KR-255 (Shin-Etsu Chemical ■) Comparative example 1 A mixture of τ-H2PC2B and tetrahydrofuran 809 was kneaded for 8 hours using a ball mill (3-inch bot mill manufactured by Nippon Kagaku Pottery). .The obtained pigment dispersion was applied onto a sia aluminum plate (conductive layer) using an applicator.
It was dried at 90° C. for 30 minutes to form a charge generation layer with a thickness of about 1 μm.

Next, 2 g of PYZ, :I-P0782000 29 and 30 g of tetrahydrofuran were mixed and completely dissolved. This coating liquid was applied onto the charge generation layer using an applicator and dried at 90° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm, thereby obtaining a two-layer electrophotographic photoreceptor.

Comparative Example 2 2 g of 0XZ, 2 g of 2045 xlA''j4) and 209 g of tetrahydrofuran were mixed and completely dissolved.

This coating liquid was applied with an applicator onto the same charge generation layer as that prepared in Comparative Example 1, and dried at 90°C for 30 minutes to form a charge transport layer with a thickness of 13 μm. A photoreceptor was obtained.

Comparative Example 3 A mixture of 2.0 g of τ-H2PC, 4.0 g of KR-2555, and 949 methyl ethyl ketone was milled using a ball mill.
Kneaded for hours. The obtained pigment dispersion was applied onto an aluminum plate (conductive layer) using an applicator and heated at 100°C for 1
It was dried for 5 minutes to form a charge generation layer with a thickness of about 1 μm.

Next is 0XZ59. Byron 200 159 was mixed with 80 g of tetrahydrofuran and completely dissolved.

This coating liquid was applied onto the charge generation layer using an applicator and dried at 90° C. for 30 minutes to form a charge transport layer having a thickness of 15 μm, thereby obtaining a two-layer electrophotographic photoreceptor.

Examples 1 to 5 Each material having the compounding ratio shown in Table 1 (unit duplex i%) was mixed in tetrahydrofuran so that the solid content was 20% by weight, and this liquid was kneaded using a ball mill for 10 hours. The resulting dispersion was applied onto a sialuminum plate using an applicator and dried at 100° C. for 15 minutes to obtain a single-layer electrophotographic photoreceptor having a thickness of 15 μm.

Table 1 also shows the results of measuring the electrophotographic properties of the obtained electrophotographic photoreceptor using an electrostatic recording paper tester (5P-428 manufactured by Kawaguchi Denki).

In addition, the symbol ■ or e in the table indicates that a positive or negative 5KV corona was discharged for 10 seconds, the initial potential (Vo) indicates the charged potential at that time, and the dark decay (VK) indicates the discharge after leaving it in the dark for 30 seconds. The half-reduction exposure i CBso ) shows the light amount value until the potential is halved when 10 Jux of white light is irradiated.

From Table 1, the electrophotographic photoreceptors of Comparative Examples 1, 2, and 3 exhibit good electrophotographic properties when negatively charged, but exhibit no sensitivity at all when positively charged. On the other hand, the electrophotographic properties of the electrophotographic photoreceptors of Examples 1 to 4 according to the present invention are good for both positive and negative charging, and the sensitivity is better when charged positively than when charged negatively.

(Effects of the Invention) As described above, the electrophotographic photoreceptor of the present invention is characterized by having good electrophotographic properties for both positive and negative charging.
It is an electrophotographic photoreceptor with a wide range of applications.

Claims (1)

[Claims] 1. A single-layer positively and negatively chargeable electron beam formed by forming a photosensitive layer containing at least one charge-generating material and charge-transporting material among τ, τ', η, and η' type gold metal phthalocyanines on a conductive layer. Photographic photoreceptor.