JPH01107263A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the sensitivity and repeatability of an electrophotographic sensitive body by forming a photosensitive layer contg. at least one kind of specified hydrazone compd. on an electroconductive base body. CONSTITUTION:At least one kind of hydrazone compd. expressed by formula I is contained in a photosensitive layer 20 formed on an electroconductive base body 1. In formula I, R1 is a (substituted)aryl group; R2 is H, halogen, alkyl group, aryl group, hydroxy group, or nitro group; Ar is a (substituted) condensed polycyclic aromatic hydrocarbon. By this constitution, an electrophotographic sensitive body having high sensitivity and high repeatability is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, it is characterized in that a novel hydrazone compound is contained in a photosensitive layer formed on a conductive substrate. The present invention relates to an electrophotographic photoreceptor.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) include inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. dispersion, organic photoconductive materials such as poly-N-vinylcarbazole or polyvinylanthracene, organic photoconductive materials such as phthalocyanine compounds or bisazo compounds, or dispersion of these organic photoconductive materials in a resin binder. Those that have been made are used.

The photoreceptor also has the ability to retain surface charge in the dark.

It is necessary to have the function of receiving light and generating a charge, as well as the function of receiving light and transporting a charge. There is a so-called laminated photoreceptor in which functionally separated layers are laminated, including a layer that contributes to charge generation, a layer that contributes to surface charge retention in the dark, and a layer that contributes to charge transport during light reception. For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation in this method involves charging the photoconductor in a dark place by corona discharge, forming electrostatic latent images such as letters and pictures on the document by exposing the surface of the charged photoconductor, and This is done by developing a latent image with toner, transferring the developed toner image to a support such as paper, and fixing it. After the toner image has been transferred, the photoreceptor is subjected to static neutralization, removal of residual toner, photostatic static elimination, etc. Subject to reuse.

In recent years, electrophotographic photoreceptors using organic materials have been put into practical use due to their advantages such as flexibility, thermal stability, and film-forming properties. For example, poly-N-vinylcarbazole and 2.
4. t-) dinitrofluoren-9-one (described in U.S. Pat. No. 3,484,237), a photoreceptor containing organic pigment as a main component (JP-A-47-37543)
(described in Japanese Unexamined Patent Publication No. 10735/1983), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (described in Japanese Patent Application Laid-open No. 10735/1983). Furthermore, many new hydrazone compounds have also been put into practical use.

[Problem that the invention seeks to solve]

As mentioned above, organic materials have many advantages that inorganic materials do not have, but at present, no material has yet been obtained that fully satisfies all the characteristics required of electrophotographic photoreceptors. In particular, there were problems with photosensitivity and characteristics during repeated and continuous use.

The present invention has been made in view of the above points, and by using a new organic material that has never been used as a charge transporting substance in the photosensitive layer, copying with high sensitivity and excellent repeatability can be achieved. The purpose of the present invention is to provide electrophotographic photoreceptors for machines and printers.

[Means for solving problems]

In order to achieve the above object, the present invention provides an electrophotographic photoreceptor having a photosensitive layer containing at least one type of hydrazone compound represented by the following general formula (I).

[In formula (I), R1 represents an aryl group which may have a substituent, and R2 is a hydrogen atom or a halogen atom.

It represents any one of an alkyl group, an aryl group, a hydroxyl group, and a nitro group, and Ar represents a condensed polycyclic aromatic hydrocarbon which may have a substituent. [Function] There is no known example in which a hydrazone compound represented by the general formula (I) is used in a photosensitive layer. In order to achieve the above objective, the present inventors conducted a number of experiments on these hydrazone compounds while conducting intensive studies on various organic materials. It has been discovered that the use of a specific hydrazone compound represented by the general formula (I) as a charge transporting substance is extremely effective in improving electrophotographic properties, and the present invention has developed a photoreceptor with high sensitivity and excellent repeatability. I was able to obtain this.

〔Example〕

The hydrazone compound of the general formula (1) used in the present invention can be synthesized by a conventional method. That is, it can be obtained by condensing aldehydes or carbonyl compounds with hydrazines in a suitable organic solvent such as alcohol, using a small amount of acid as a condensing agent if necessary.

Specific examples of the hydrazone compound represented by the general formula (I) thus obtained are as follows.

The photoreceptor of the present invention contains the above-mentioned hydrazone compounds in the photosensitive layer.

It can be used as shown in FIG. 2 or 3.

1, 2, and 3 are conceptual cross-sectional views of different embodiments of the photoreceptor of the present invention, in which 1 is a conductive substrate, 2 is a conductive substrate, and 2 is a conductive substrate.
0.21.22 is a photosensitive layer, 3 is a charge generating material, 4 is a charge generating layer, 5 is a charge transporting material, 6 is a charge transporting layer, and 7 is a coating layer.

FIG. 1 shows a photosensitive layer 20 (usually single-layer type photosensitive layer 20 ('i!1) in which a charge generating substance 3 and a hydrazone compound as a charge transporting substance 5 are dispersed in a resin binder (binder) on a conductive substrate 1. A structure called a body) is provided.

FIG. 2 shows a photosensitive layer 21( The structure is usually referred to as a laminated photoreceptor). A photoreceptor having this configuration is normally used in a negative charging system.

FIG. 3 shows a layer structure opposite to that in FIG. 2, and is normally used in a positive charging system. In this case, it is common to further provide a coating layer 7 to protect the charge generation layer 4.

The reason why the laminated photoreceptor has two types of layer configurations is that even if a photoreceptor with the layer configuration shown in Figure 2 is used in a positive charging system, there is currently no charge transporting material that is compatible with this. This is because it has not been found. At present, when applying a positive charging method to a laminated type photoreceptor, it is necessary to use a photoreceptor having the layer structure shown in FIG.

The photoreceptor shown in FIG. 1 can be produced by dispersing a charge generating substance in a solution containing a charge transporting substance and a resin binder, and applying this dispersion onto a conductive substrate.

The photoreceptor shown in Figure 2 is produced by vacuum-depositing a charge-generating substance on a conductive substrate, or by coating and drying a dispersion obtained by dispersing particles of a charge-generating substance in a solvent or resin binder, and then It can be produced by applying a solution containing a charge transporting substance and a resin binder to a substrate and drying the solution.

The photoreceptor shown in Fig. 3 is made by coating a conductive substrate with a solution containing a charge transporting substance and a resin binder and drying it, and then vacuum-depositing a charge generating substance thereon, or by depositing charge generating substance particles thereon. It can be produced by coating and drying a dispersion obtained by dispersing in a solvent or resin binder.

The conductive substrate 1 serves as an electrode for the photoreceptor and at the same time serves as a support for the other layers, and may be cylindrical, plate-shaped, or film-shaped, and may be made of aluminum, stainless steel, nickel, etc. It may also be made of metal, glass, resin, or the like, which has been subjected to conductive treatment.

The charge generation layer 4 is formed by applying a material in which particles of the charge generation substance 3 are dispersed in a resin binder as described above, or by a method such as vacuum deposition, and generates charges by receiving light. . In addition, the charge transport layer e and the coating layer 7 for the generated charges are also highly efficient.
It is important to have good injection properties even in low electric fields with little dependence on electric fields. Examples of the charge generating substance include phthalocyanine compounds such as metal-free phthalocyanine and titanyl phthalocyanine, various azo, quinone, and indigo pigments, or cyanine and squarylium.

Dyes such as azulenium and biryllium compounds, selenium or selenium compounds, and the like are used, and suitable substances can be selected depending on the light wavelength range of the exposure light source used for image formation. Since the charge generation layer only needs to have a charge generation function, its thickness is determined by the light absorption coefficient of the charge generation substance and is generally 5 μm or less, preferably 1 μm or less. The charge generation layer is mainly composed of a charge generation substance, and a charge transporting substance can also be added thereto.

As the resin binder, polycarbonate, polyester, polyamide, polyurethane, epoxy, silicone resin, polymers and copolymers of methacrylic acid ester, etc. can be used in appropriate combinations.

The charge transport layer 6 is a coating film in which a hydrazone compound represented by the general formula (I) as an organic charge transport substance is dispersed in a resin binder, and serves as an insulating layer in the dark to retain the charge on the photoreceptor. During light reception, it functions to transport charges injected from the charge generation layer. As a resin binder, polycarbonate, polyester, polyamide,
Polyurethane, epoxy, silicone resin, methacrylic acid ester polymers and copolymers, etc. can be used.

The coating layer 7 has the function of receiving and retaining the charge of corona discharge in a dark place, and has the ability to transmit the light to which the charge generation layer is sensitive, and transmits the light upon exposure, and the charge generation layer It is necessary to neutralize and eliminate the surface charges by injecting the generated charges. As the coating material, organic insulating film-forming materials such as polyester and polyamide can be used. In addition, these organic materials and glass resin, S
in.

It is also possible to use a mixture of inorganic materials such as metals, metal oxides, and other materials that reduce electrical resistance. The coating material is not limited to organic insulating film forming materials, but also inorganic materials such as 5i02, metals,
It is also possible to form a metal oxide or the like by a method such as vapor deposition or sputtering. As mentioned above, it is desirable that the coating material be as transparent as possible in the wavelength region where the charge generating substance absorbs maximum light.

The thickness of the coating layer itself depends on the composition of the coating layer, but
It can be set arbitrarily within a range that does not cause adverse effects such as an increase in residual potential when used repeatedly and continuously.

Hereinafter, specific examples of the present invention will be described.

Example 1 A polyester resin (
A coating solution was prepared by kneading 100 parts by weight of Byron 200 (trade name: Toyo Doube) and a tetrahydrofuran (THF) solvent for 3 hours in a mixer, and then preparing an aluminum-deposited polyester film (A A-P E T ) as a conductive substrate.
The film thickness after drying is 1.
A photosensitive layer was formed to have a thickness of 5 μm, and a photosensitive member having the structure shown in FIG. 1 was produced.

Example 2 First, α-type metal-free phthalocyanine is used as a starting material, and while two linear motors are placed facing each other, α-type metal-free phthalocyanine and a non-magnetic separation body containing a Teflon piece as a working piece are placed and pulverized. L I MM A C (
Linear Induction Motor Mi
x-ing and crushing (manufactured by Fuji Electric) was performed for 20 minutes to form a fine powder. 1 part by weight of this finely powdered sample and 50 parts by weight of DMF (N,N-dimethylformamide) solvent were subjected to ultrasonic dispersion treatment. Thereafter, the sample and DMF were separated and filtered, dried, and treated for metal-free phthalocyanine.

Next, a hydrazone compound 1 represented by the above compound Nα2
00 parts by weight dissolved in 700 parts by weight of tetrahydrofuran (THF) and polymethyl methacrylate polymer (P
MMA: manufactured by Tokyo Kasei Co., Ltd.) 100 parts by weight to 700 parts by weight of toluene
A coating solution prepared by mixing parts by weight of the solution was coated onto an aluminum-deposited polyester film substrate by a wire bar method to form a charge transport layer so that the film thickness after drying was 15 μm. 50 parts by weight of the above-treated metal-free phthalocyanine and 5 parts by weight of a polyester resin (trade name: Vylon 200: Toyo Doube) are placed on the charge transport layer thus obtained.
0 parts by weight, 50 parts by weight of PMMA with THF solvent
A coating solution was prepared by kneading with a time mixer, and applied using a wire bar method to form a charge generation layer with a film thickness of 1 μm after drying. The body was created. However, a coating layer not directly related to the present invention was not provided.

Example 3 The composition of the photosensitive layer of Example 1 was changed to 50% metal-free phthalocyanine.
Parts by weight, Compound No. 100 parts by weight of a hydrazone compound represented by 3, Polyester resin (trade name: Vylon 20)
A photosensitive layer was formed in the same manner as in Example 1 except that 50 parts by weight of PMMA and 50 parts by weight of PMMA were used to form a photosensitive layer to produce a photoreceptor.

Example 4 In Example 3, a photosensitive layer was formed in the same manner as in Example 1, except that chlorodiane blue, which is a bisazo pigment as disclosed in JP-A-47-37543, was used instead of the metal-free phthalocyanine. A photoreceptor was produced.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric.

The surface potential V, (volt) of the photoreceptor is +6.0kV in the dark.
This is the initial surface potential when corona discharge is performed for 10 seconds to positively charge the surface of the photoreceptor, and the surface potential Vd is then maintained in the dark for 2 seconds with corona discharge stopped.
(volts), and then the illuminance 2 on the photoreceptor surface.
The time (seconds) required for Vd to be halved after irradiation with lux white light was determined and defined as half-attenuation exposure IE+/□ (lux seconds). Further, the surface potential when white light with an illuminance of 2 lux was irradiated for 10 seconds was defined as the residual potential Vr (volt). In addition, when a phthalocyanine compound is used as a charge generating substance, high sensitivity with long wavelength light can be expected.
Electrophotographic characteristics when using n+n monochromatic light were also measured at the same time. That is, measurements are carried out in the same manner up to ■, then 1 μW monochromatic light (7gOr++n) is irradiated instead of white light to obtain the half-attenuation exposure amount (μJ/crl), and this light is applied to the photoreceptor for 10 seconds. Residual potential V when irradiating the surface,
(volts) was measured. The measurement results are shown in Table 1.

As seen in Table 1, the photoreceptors of Examples 1, 2, 3, and 4 had no difference in half-attenuation exposure or residual potential, and exhibited good characteristics in terms of surface potential.

Further, even for long wavelength light of 780 nm, the photoreceptors of Examples 1, 2 and 3 in which a phthalocyanine compound was used as a charge generating substance exhibited excellent electrophotographic properties.

Example 5 Selenium was deposited to a thickness of 1 on a 500 μm thick aluminum plate.
．． A charge generation layer was formed by vacuum evaporation to a thickness of 5 μm, and then a solution obtained by dissolving 100 parts of a hydrazone compound represented by compound Nα4 in 700 parts by weight of tetrahydrofuran (THF) and polymethyl methacrylate polymer (PMMA: manufactured by Tokyo Kasei) were added. ) was mixed with a solution prepared by dissolving 100 parts by weight of toluene in 700 parts by weight of toluene, and the resulting coating liquid was applied using a wire bar method to form a charge transport layer so that the film thickness after drying was 20 μm. A photoreceptor having the configuration shown in FIG. 2 was manufactured. When this photoreceptor was corona charged at -6.0 kV for 0.2 seconds and its electrophotographic characteristics were measured, V, = -650V,
Good results were obtained with V=-50V and El/2=4.1 lux·sec.

Example 6 50 parts by weight of the metal-free phthalocyanine treated in Example 1, 50 parts by weight of polyester resin (trade name Byron 200: Toyo Dobu), and 50 parts by weight of PMMA were mixed together with THF solvent for 3 hours using a mixer and applied. The solution was prepared and coated onto an aluminum support to a thickness of about 1 μm to form a charge generation layer. Next, 100 parts by weight of a hydrazone compound represented by compound Nα5, 100 parts by weight of polycarbonate resin (Panlite L-1250), and 0.1 parts by weight of silicone oil were mixed with 700 parts by weight of THF and 700 parts by weight of toluene to form a charge generation layer. A charge transport layer was formed by coating the film to a thickness of approximately 15 μm.

The thus obtained photoreceptor was corona charged at -6.0 kV for 0.2 seconds in the same manner as in Example 5, and its electrophotographic properties were measured.
A good result was obtained with z=5.2 lux·sec.

Example 7 A photosensitive layer was prepared in the same manner as in Example 4 for each of the compounds Nα6 to Nα21 to form a photoreceptor, and r S P -42
Table 2 shows the results of measuring the half-attenuation exposure using 8J.

A corona discharge of +6.0 kV was performed for 10 seconds in a dark place to positively charge the sample, and the half-attenuation exposure when irradiated with white light at an illuminance of 2 lux was expressed as IEl/2 (lux seconds).

Table 2 (Part 1) As seen in Table 2, the hydrazone compound N[L
The half-attenuation exposure amount E 1 / 2 + , that is, the sensitivity was also good for the photoreceptors using Nα 6 to Nα21.

〔Effect of the invention〕

According to the present invention, since the hydrazone compound represented by the general formula (I) is used as a charge transporting substance on a conductive substrate, a photosensitive material with high sensitivity and excellent repeatability even in positive and negative charging can be obtained. You can get a body. In addition, a suitable charge-generating substance can be selected depending on the type of exposure light source; for example, by using phthalocyanine compounds and certain bisazo compounds, a photoreceptor that can be used in semiconductor laser printers can be obtained. be able to. Furthermore, if necessary, it is possible to provide a coating layer on the surface to improve durability.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are conceptual sectional views showing different embodiments of the photoreceptor of the present invention. 1 conductive substrate, 3 charge generation substance, 4 charge generation layer,
5 charge transport substance, 6 charge transport layer, 7 coating layer,
20.21.22 Photosensitive layer.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one hydrazone compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [In formula (I), R_1 represents an aryl group that may have a substituent, and R_2 represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group. represents either a group or a nitro group,
Ar represents a fused polycyclic aromatic hydrocarbon which may have a substituent. ]