JPH01172961A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body for copying machines and printers which has high sensitivity and excellent repetitive characteristics by providing a photosensitive layer contg. at least one kind among specific hydrazone compds. CONSTITUTION:The photosensitive layer contg. at least one kind among the hydrazone compds. expressed by the formula I is provided. In the formula I, R1-R3 respectively denote any of a hydrogen atom., halogen atom., alkyl group, hydroxy group, alkoxy group, aryl group which may be substd., amino group or nitro group; R4 denotes an aryl group which may be substd.; n denotes 0 or 1. The photosensitive body having the high sensitivity and the excellent repetitive characteristics is thereby 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. dispersions, organic photoconductive materials such as poly-N-vinylcarbazole or polyvinylanthracene, organic photoconductive materials such as phthalocyanine compounds or bisazo compounds dispersed in resin binders or vacuum evaporated. Things are being used.

In addition, the photoreceptor needs 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, but one layer is required. We developed a so-called single-layer photoreceptor that has both of these functions, and a layer that is functionally separated into a layer that mainly 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. There is a so-called laminated type photoreceptor. 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 and fixing the developed toner image on a support such as paper. After the toner image is transferred, the photoreceptor is subjected to static neutralization, residual toner removal, photostatic static elimination, etc., and then it is reused. served.

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, pog N-vinylcarbazole and 2
．． 4.7-) Danitrofluoren-9-one (described in U.S. Pat. No. 3,484,237),
Photoreceptor containing organic pigment as main component (Japanese Patent Application Laid-Open No. 47-3754
3), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (described in JP-A-47-10735). Furthermore, many new hydrazone compounds have also been put into practical use.

[Problem that the invention seeks to solve]

However, although organic materials have many advantages that inorganic materials do not have, the current situation is that organic materials that fully satisfy all of the characteristics required for electrophotographic photoreceptors have not been obtained, such as high sensitivity and A photoreceptor with excellent repeatability is strongly desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor for copying machines and printers that has high sensitivity and excellent repeatability.

[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), R+, Rs and R3 are each a hydrogen atom, a halogen atom, an alkyl group, or a hydroxy group.

It represents any one of an alkoxy group, an optionally substituted aryl group, an amino group, or a nitro group, R4 represents an optionally substituted aryl group, and n represents either 0 or 1.

] [Function] There is no known example of using the hydrazone compound represented by the general formula (1) 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. We have discovered that the use of a specific hydrazone compound represented by the above general formula (I) as a charge transport material is extremely effective in improving electrophotographic properties, and we have developed a photoreceptor with high sensitivity and excellent repeatability. I ended up getting it.

〔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 (1) thus obtained are as follows.

Compound N? 31 N932 The photoreceptor of the present invention contains the above-described hydrazone compound in the photosensitive layer.

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

1 to 3 are conceptual cross-sectional views of the photoreceptor of the present invention.
20, 21 and 22 are a conductive substrate, 20, 21 and 22 are photosensitive layers, 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 (commonly 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 l. ) is provided.

FIG. 2 shows a photosensitive layer 2 consisting of a stack of 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 on a conductive substrate 1.
1 (a configuration commonly referred to as a laminated photoreceptor).

FIG. 3 shows an inverse layer configuration to that of FIG.

In this case, it is common to further provide a coating layer 7 to protect the charge generation layer 4.

The reason for the two types of layer configurations shown in Figures 2 and 3 is that even if you try to use the layer configuration in Figure 2, which is normally used for a negative charging system, in a positive charging system, there is no compatible charge transport material. This is because it has not been found yet, and therefore, at this stage, it is necessary to create a photoreceptor with the layer structure shown in FIG.

The photoreceptor shown in FIG. 1 can be produced by dispersing a charge generating material in a solution containing a charge transporting material 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 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 l 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 charge generation substance 30 particles 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 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. 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 pyrylium compounds, selenium or selenium compounds 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 transport substance or the like may 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 and prevent light During reception, it functions to transport charges injected from the charge generation layer. As the resin binder, polycarbonate, polyester, polyamide, polyurethane, epoxy, silicone resin, polymers and copolymers of 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 coating material, organic insulating film-forming materials such as polyester and polyamide can be used. In addition, these organic materials and glass resin, S
It is also possible to use a mixture of inorganic materials such as in□ and materials that reduce electrical resistance such as metals and metal oxides. The coating material is not limited to organic insulating film forming materials (it is also possible to form inorganic materials such as 5i02, metals, metal oxides, etc. by methods such as vapor deposition and sputtering. As mentioned above, it is desirable that the charge generating material be as transparent as possible in the wavelength region where the light absorption is maximum.

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 50 parts by weight of metal-free phthalocyanine (manufactured by Tokyo Kasei Co., Ltd.) ground for 150 hours in a ball mill and 100 parts by weight of the hydrazone compound represented by 1 were mixed with 100 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) and tetrahydrofuran. (THF) A coating solution was prepared by kneading it with a solvent for 3 hours using a compounding machine, and then coating it on an aluminum vapor-deposited polyester film (^j!-P, ET), which is a conductive substrate, using a wire paper method. , film thickness after drying is 15μ
A photosensitive layer is formed so that it becomes 11th! A photoreceptor having the configuration shown in 1 was produced.

Example 2 First, α-type metal-free phthalocyanine was used as a starting material, and while two linear motors were placed facing each other, α-type metal-free phthalocyanine and a nonmagnetic separation body containing a Teflon-coated magnetic piece as a working piece were mixed. 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 and DMF (N,N-dimethylformamide)
Ultrasonic dispersion treatment was performed with 50 parts by weight of a solvent. after that,
The sample and DMF were separated and filtered, dried, and processed 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 pur 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 a polyester resin (trade name: Vylon 200 manufactured by Toyobo Co., Ltd.) 5
A coating solution was prepared by kneading 0 parts by weight and 5'0 parts by weight of PMMA with a THF solvent in a blender for 3 hours, and the charge generation layer was coated using a wire pudding method so that the film thickness after drying was 1 μm. A photoreceptor corresponding to the structure shown in FIG. 3 was prepared.

Example 3 The composition of the photosensitive layer of Example 1 was changed to 50% metal-free phthalocyanine.
Part by weight, hydrazone compound 10 represented by compound Nα3
0 parts by weight, polyester resin (trade name Byron 200:
A photosensitive layer was formed in the same manner as in Example 1, except that 50 parts by weight of PMMA (manufactured by Toyobo Co., Ltd.) and 50 parts by weight of PMMA were used to prepare a photoreceptor.

Example 4 In Example 3, a photosensitive layer was formed in the same manner as in Example 1 using chlorodiane blue, which is a suazo pigment, such as shown in JP-A-47-37543, instead of metal-free phthalocyanine, to produce a photoreceptor. did.

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 +6.9kV 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 then the surface potential is V when the corona discharge is stopped and the surface is held in the dark for 2 seconds.
a (volts), and then irradiate the surface of the photoconductor with white light with an illuminance of 2 lux to find the time (seconds) until vd is halved and calculate the half-attenuation exposure amount E172 (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 properties using 0 nm monochromatic light were also measured at the same time. That is, measurements were taken in the same manner up to Vd, and then the half-attenuation exposure amount (μJ/cd) was determined by irradiating lμ trout with monochromatic light (780 nm) instead of white light, and this light was applied to the photoreceptor for 10 seconds. Residual potential Vr when the surface is irradiated (
Volts) were measured. The measurement results are shown in Table 1.

As seen in Table 1, Examples 1.2.3.4 are comparable in half-attenuation exposure and residual potential, and also exhibit good characteristics in terms of surface potential. Further, it can be seen that Examples 1.2.3 in which a phthalocyanine compound was used as the charge generating substance showed high sensitivity even with long wavelength light of 780 nm, and could be sufficiently used for semiconductor radar 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 obtained by dissolving 100 parts by weight 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. A coating solution prepared by mixing 100 parts by weight of toluene with 700 parts by weight of toluene 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 the figure was manufactured. When this photoreceptor was corona charged at -6, OkV for 0.2 seconds, the voltage was -650V.

Good results were obtained with V=-60V and El/2=5.0 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, manufactured by Toyobo), and 50 parts by weight of PMMA were kneaded with a THF solvent in a mixer for 3 hours to prepare a coating solution. A charge generating layer was prepared and coated on an aluminum support to a thickness of about 1 μm. 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 parts by weight of silicone oil were added.
．． One layer and one layer were mixed with 700 parts by weight of THF and 700 parts by weight of toluene and coated on the charge generation layer to a thickness of about 15 μm to form a charge transport layer.

When the thus obtained photoreceptor was corona charged at -6,0kV for 0.2 seconds in the same manner as in Example 5, Vs = -600V, E l/2 = 4.9.
Good results were obtained in terms of looks and seconds.

Example 7 A photosensitive layer was formed in the same manner as in Example 4 for each of compounds Nα6 to No. 36, and a photoreceptor was produced.
Table 2 shows the results measured using ``. This result is
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 amount El/□ (lux seconds) was shown when white light with an illuminance of 2 lux was irradiated.

Table 2 (Part 1) Table 2 (Part 2) As seen in Table 2, the hydrazone compound Nα6
The half-attenuation exposure amount E1/2 was also good for the photoconductor using ~N(136) as the charge transport material.

〔Effect of the invention〕

According to the present invention, since the hydrazone compound represented by the general formula (I) is used as a charge transport material on the conductive substrate, the photoreceptor is highly sensitive even when positively charged and negatively charged, and has excellent repeatability. can be obtained. In addition, suitable charge-generating substances can be selected depending on the type of exposure light source; for example, phthalocyanine compounds and certain bisazo compounds can be used to create photoreceptors that can be used in semiconductor laser printers. Obtainable. 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. −

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), R_1, R_2 and R_3 are each a hydrogen atom, a halogen atom, an alkyl group, a hydroxy group, an alkoxy group, an optionally substituted aryl group, It represents either an amino group or a nitro group, R_4 represents an optionally substituted aryl group, and n represents either 0 or 1. ]