JPH0394263A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form the photosensitive body having a high sensitivity and excellent repetitive characteristics for copying machines and printers by providing a photosensitive layer contg. one kind of specific hydrazone compds. CONSTITUTION:The photosensitive layer contg. at least one kind of the hydrazone compds. expressed by formula I is provided. In the formula I, A denotes either of a substd. or unsubstd. condensation polycyclic arom. residual group or residual heterocyclic group; R1 to R3 respectively denote a hydrogen atom, and any of a respectively substd. or unsubstd. alkyl group, aryl group, alkenyl group, and anil group. The photosensitive body having the high sensitivity and the excellent repetitive characteristics is obtd. in this way.

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 a photoreceptor for electrophotography.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) have been made of inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. organic photoconductive substances such as polyvinyl carbazole or polyvinylanthracene, organic photoconductive substances such as phthalocyanine compounds or bisazo compounds dispersed in a resin binder, or vacuum evaporated. and other items are being used.

In addition, a photoreceptor must have the function of retaining surface charge in the dark, the function of receiving light and generating charge, and the function of receiving light and transporting charge, all of which can be achieved in one layer. A so-called single-layer photoreceptor with the following functions is laminated with functionally separated layers: a layer that mainly contributes to charge generation, and a layer that contributes to surface charge retention in the dark and charge transport during light reception. There is a so-called laminated photoreceptor. For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. In this method, the image form or electrostatic latent image such as text or pictures on a document is formed by charging the photoreceptor in a dark place by corona discharge, or by exposing the charged photoreceptor surface to light. Development of an electrostatic latent image with toner, and transfer of the developed toner image to a support such as paper. This is done by fixing, and after the toner image is transferred, the photoconductor undergoes static electricity removal, residual toner removal,
After photostatic charge removal, etc., it is reused.

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 formability. For example, polyJN-vinylcarbazole and 2.
4.7-IJ nitrofluorene-9-one (described in U.S. Pat. No. 3,484,237),
Photoreceptor mainly containing organic pigment (Japanese Patent Application Laid-Open No. 47-3754
(described in Japanese Patent Application Laid-open No. 10785/1983), and a photoreceptor mainly composed of a eutectic complex consisting of a dye and a resin (described in Japanese Patent Application Laid-open No. 10785/1983). Furthermore, many new hydrazone compounds have also been put into practical use.

[Problem to be solved by the invention]

As mentioned above, organic materials have many advantages that inorganic materials do not have, but at the same time, there is currently no material that fully satisfies all the characteristics required of electrophotographic photoreceptors. There were problems with photosensitivity and characteristics during repeated and continuous use.

This invention was made in view of the above points, and
Our objective is to provide an electrophotographic photoreceptor for copying machines and printers that has high sensitivity and excellent repeatability by using a new organic material that has never been used as a charge transport material in the photosensitive layer. do.

[Means to solve the problem]

According to the present invention, the above problem is solved by providing an electrophotographic photoreceptor having a photosensitive layer containing at least one type of hydrazone compound represented by the following general formula (1).

[In formula (I), A represents either a substituted or unsubstituted integrated polycyclic aromatic residue or a heterocyclic residue, R1 to R3 are each a hydrogen atom, and each of the following substituted or unsubstituted Alkyl group. Aryl group, alkenyl group. Represents any anyl group. ] [Operation] There are no known examples of using the hydrazone compound represented by the above general formula (1) in a photosensitive layer.The present inventors, while intensively studying various organic materials in order to solve the above problems, As a result of numerous experiments conducted on these hydrazone compounds, although the technical elucidation has not yet been fully elucidated, it is possible to use such a specific hydrazone compound represented by the above general formula (1) as a charge transport material. but,
discovered that it is extremely effective in improving electrophotographic properties,
This led to the creation of a photoreceptor with high sensitivity and excellent repeatability.

〔Example〕

The hydrazone compound of the primary formula (1) used in this invention can be synthesized by a conventional method. That is, aldehydes represented by the following general formula (II>) and hydrazines represented by the following general formula (III) are mixed in a suitable organic solvent (e.g. ethanol etc.) in the presence of a catalyst such as an acid.
By dehydrating and condensing the mixture in a liquid, it is possible to easily combine the precepts.

Specific examples of the hydrazone compound represented by the general formula (1) thus obtained are as follows.The photoreceptor of the present invention contains the above-mentioned hydrazone compound in the photosensitive layer. Depending on the application of the hydrazone compound, it can be used as shown in FIG. 1, FIG. 2, or FIG. 3.

1 to 3 are conceptual cross-sectional views of the photoreceptor of the present invention,
l is a conductive substrate, 20, 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 transport layer, and 7 is a coating layer.

FIG. 1 shows a photosensitive layer 20 (usually referred to as a single-layer photoreceptor) in which a charge generating substance 3 and a hydrazone compound as a charge transporting substance 5 are dispersed in a resin binder on a conductive substrate 1. ) is provided.

FIG. 2 shows a photosensitive layer 2 consisting of a conductive substrate laminated with a charge generation layer 4 mainly containing a charge generation substance 3 and a charge transport layer 6 containing a hydrazone compound as a charge transport substance 5.
1 (a structure commonly referred to as a laminated photoreceptor).

In FIG. 3, a photosensitive layer 22 having a layer structure opposite to that in FIG. 2 is provided. In this case, it is common to further provide a coating layer 7 to protect the charge generation layer 4.

The reason for using the two types of layer structures shown in Figures 2 and 3 is that even if the layer structure shown in Figure 2, which is normally used for a negative charging system, is intended to be used for a positive charging system, the charge transport that is compatible with this is This is because the substance has not yet been discovered, and therefore, at this stage, it is necessary to have the layer structure shown in FIG. 3 as a positively charging type photoreceptor.

The photoreceptor shown in FIG. 1 can be prepared by dispersing a charge generating material in a solution containing a charge transporting material and a resin binder, and coating this dispersion on 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 the surface of the substrate and drying the solution.

The photoreceptor shown in Figure 3 is produced 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 in a solvent or a solvent. It can be produced by applying a dispersion obtained by dispersing it in a resin binder, drying it, and further forming a coating layer.

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 coating 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. do. In addition, the charge transport layer 6 and the coating layer 7 for the generated charges at the same time have a high charge generation efficiency.
It is important to have good injection properties even in low electric fields with little dependence on electric fields. As the charge generating substance, phthalocyanine compounds such as metal-free phthalonanine and titanyl phthalocyanine, various azo, quinone, and indigo pigments, dyes such as cyanine, squarium, azulenium, and pyrylium compounds, and selenium or selenium compounds are used. A suitable material 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.
It is 1 μm or less, preferably 1 μm or less. The charge generation layer is mainly composed of a charge generation substance, and a charge transport substance or the like may be added thereto.

As the resin binder, polycarbonate, polyester, polyamide, polyurethane, vinyl chloride, epoxy, diallyl phthalate resin, 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 (+.) is dispersed as an organic charge transport substance 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,
Polymers and copolymers of polyurecne, epoxy, silicone resin, methacrylic acid ester, 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 covering material, an organic insulating film material such as polyester or polyamide can be used. In addition, these organic materials and glass resin, S
Inorganic materials such as i02 and even metals. It can also be used in combination with a material that reduces electrical resistance, such as a metal oxide. The coating material is not limited to organic insulating films or materials; inorganic materials such as SI02, as well as metals, metal oxides, etc., may be deposited. It is also possible to shape by a method such as 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.

Examples of the present invention will be described below.

Example 1 100 parts by weight of a polyester resin (trade name Byron 200, manufactured by Toyobo Co., Ltd.) was mixed with 50 parts by weight of metal-free lid cyanine (Tokyo Chemical Co., Ltd.) ground for 150 hours in a ball mill and 100 parts by weight of the hydrazone compound represented by the compound Nch 1. and tetrahydrofuran (THF) solvent for 3 hours in a mixer to prepare a coating solution.
A photosensitive layer was formed by applying the photosensitive layer onto T) using a wire bar method so that the film thickness after drying was 15 μm, thereby producing a photosensitive member having the structure shown in FIG.

Example 2 First, α-type metal-free phthalocyanine was used as a starting material, and a non-magnetic case containing α-type metal-free phthalocyanine and a coated magnetic Teflon piece as a working piece was used between two linear motors arranged facing each other. The powder was pulverized for 20 minutes using an electromagnetic pulverizer (trade name: LIMMAC, manufactured by Fuji Electric). 1 part by weight of this finely powdered sample. ! = DMF (N,N-dimethylformamide) 50 parts by weight of solvent was subjected to ultrasonic dispersion treatment. Thereafter, the sample and DMF were separated and filtered, and dried to perform metal-free phthalocyanine treatment.

Next, a hydrazone compound 8 represented by the compound Nα2
0 weight 1 part and polycarbonate resin (product name Banrai)
A coating solution prepared by dissolving 100 parts by weight of L-1225 (manufactured by Teijin) in methylene chloride was applied onto an aluminum-deposited polyester film substrate using the wire bar method, and charge transport was applied so that the film thickness after drying was 15 μm. The layers were formed. On the charge transport layer thus obtained, 50 parts by weight of the above-treated metal-free phthalocyanine and 50 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo) were kneaded with a THF solvent in a mixer for 3 hours. A coating solution was prepared and applied using a wire bar method, and a charge generation layer was formed so that the film thickness after drying was 1 μm, and a photoreceptor corresponding to the structure shown in Fig.'fJ3 was prepared. did. However, a coating layer not directly related to this invention was not provided.

Example 3 The metal-free phthalocyanine in Example 2 was expressed by the following structural formula (
A photoreceptor was produced in the same manner as in Example 2 except that the squarylium compound represented by IV) was replaced with a hydrazone compound represented by the compound Nα3 as the charge transport material.

Example 4 The metal-free phthalocyanine in Example 2 was replaced with chlorodiane blue, which is a bisazo pigment as shown in JP-A No. 47-37543, and the charge transport material was replaced with a hydrazone compound represented by the compound Nα4. ,
A photoreceptor was produced in the same manner as in Example 2 in other respects.

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

Surface potential of photoreceptor V. (Volt) is +6 in the dark. Ok
This is the initial surface potential when corona discharge of V is performed for 10 seconds to positively charge the surface of the photoreceptor, and then the surface potential V is when the corona discharge is stopped and the surface is held in the dark for 2 seconds.
, (volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux to find the time (seconds) it takes for vd to be halved.
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 V, (volt). Further, for Examples 1 to 3, since high sensitivity with long wavelength light can be expected, the electrophotographic characteristics when using monochromatic light with a wavelength of 780 nm were also measured at the same time. That is, ■,
Measurements were carried out in the same manner up to the previous step, and then 1 μW monochromatic light (780 nm) was irradiated instead of white light to obtain a half-attenuation exposure amount (μJ/c
at) was determined, and the residual potential V, (volt) when the surface of the photoreceptor was irradiated with this light for 10 seconds was measured.

The measurement results are shown in Table 1.

As shown in Table 1, Examples 1, 2, and 3.4 are comparable in half-attenuation exposure and residual potential, and also exhibit good characteristics in terms of surface potential.

Further, Examples 1 to 3 showed high sensitivity even to long wavelength light of 730 nm, and it was found that they could be sufficiently used for semiconductor laser printers.

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 prepared by dissolving 100 parts by weight of a hydrazone compound represented by Compound N (L 5) in 700 parts by weight of tetrahydrofuran (THF) and polymethyl methacrylate polymer (PMMA:
A charge transport layer was formed by mixing 100 parts by weight (manufactured by Tokyo Kakai Co., Ltd.) with 700 parts by weight of toluene and applying it using the wire bar method, so that the film thickness after drying was 20 μm. A photoreceptor having the shape or structure shown in FIG. 2 was manufactured.

For this photoreceptor, the corona discharge voltage was set to -6, OkV.
When the electrophotographic characteristics were measured in the same manner as the above-mentioned measurement method except for Vs=-600V. vr=
-50v, El/2=4.5/L'-/cus·sec, and good results were obtained.

Example 6 50 parts by weight of the metal-free phthalocyanine treated in Example 2 and 50 parts by weight of vinyl chloride copolymer (trade name: MR-110 manufactured by Nippon Zeon) were kneaded with methylene chloride in a mixer for 3 hours to prepare a coating solution. was prepared and coated on an aluminum support to a thickness of about 1 μm to form a charge generation layer. Next, hydrazone compound 10 represented by compound Nα6
0 parts by weight, polycarbonate resin (product name Banrai)
L-1250: manufactured by Teijin) 100 parts by weight. 0.1 part by weight of silicone oil was mixed with methylene chloride and applied to the charge generation layer to a thickness of about 15 μm to form a charge transport layer, producing a photoreceptor having the structure shown in Figure 2. did.

When the electrophotographic characteristics of the thus obtained photoreceptor were measured in the same manner as in Example 5, V. =-75
Good results were obtained at 0V and El/l=3.8 lux·sec.

Example 7 The metal-free phthalocyanine in Example 6 was replaced with a bisazo pigment represented by the following structural formula (V), and the charge transport substance was replaced with a hydrazone compound represented by compound N (L 7), and the other procedures were as in Example 6. A photoreceptor was produced in the same manner.

When the electrophotographic characteristics of the thus obtained photoreceptor were measured in the same manner as in Example 5, Va = -6
Good results were obtained at 30V and El/2 = 5.4 lux' seconds.

Example 8 Photoreceptors were prepared in the same manner as in Example 4 for each of Compounds N118 to N121, and the electrophotographic properties were measured using rSP-428J. The results are shown in Table 2.

+6 in the dark. Corona discharge at OkV was performed for 10 seconds to positively charge the sample, and the half-attenuation exposure was expressed as ffiE+/z (lux seconds) when white light with an illuminance of 2 lux was irradiated.

Table 2 As seen in Table 2, the hydrazone compound Nα8
The half-attenuation exposure 11E1y2 was also good for the photoreceptor using ~Nα21 as the charge transport material.

〔Effect of the invention〕

According to this invention, since the hydrazone compound represented by the above-mentioned one-ship formula (1) is used as a charge transport material 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, suitable charge-generating substances can be selected depending on the type of exposure light source. For example, phthalocyanine compounds, squaryliwam compounds, and certain bisazo compounds can be used in semiconductor laser printers. A photoreceptor can be obtained. Furthermore, if necessary, it is possible to provide a coating layer on the surface to improve durability.

[Brief explanation of drawings]

1, 2, and 3 are conceptual sectional views showing different embodiments of the photoreceptor of the present invention.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one type of hydrazone compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) [In formula (I), A represents either a substituted or unsubstituted fused polycyclic aromatic residue or a heterocyclic residue, and R_1
to R_3 each represent a hydrogen atom, or each of the following substituted or unsubstituted alkyl groups, aryl groups, alkenyl groups, and anyl groups. ]