JPH01164950A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body for a copying machine and printer having a high sensitivity and excellent repeating characteristics by incorporating hydrazone compds. into a photosensitive layer formed on a conductive base body. CONSTITUTION:At least one kind of the hydrazone compds. expressed by either of the formulas I and II is incorporated into the photosensitive layer. In the formulas I and II, R1-R4 and R7 respectively denote a hydrogen atom., halogen atom., alkyl group, alkoxy group, hydroxy group, acyl group, nitro group, aryl group which may be substd., and amino group; R5 and R6 denotes an aryl group which may be substd. and (n) denotes either of 1 and 2. The photosensitive body having the high sensitivity and excellent repeating 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 a photoreceptor for electrophotography.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) have been made using inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. What is dispersed, po'
Organic photoconductive substances such as J-N-vinylcarbazole or polyvinylanthracene, phthalocyanine compounds, or bisazo compounds dispersed in a resin binder or vacuum-deposited are used. ing.

In addition, the photoreceptor must have the ability to retain surface charge in the dark, the ability to receive light and generate charge, and the function to receive light and transport charge. A so-called single-layer type photoreceptor that has both functions, and a so-called laminated layer with functionally separated layers: 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 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, and forming electrostatic latent images such as letters and pictures on the original using N light on the surface of the charged photoconductor. This is done by developing an electrostatic latent image with toner and fixing the developed toner image on a support such as paper.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, polyJN-vinylcarbazole and 2.
4,7-dolinitrofluoren-9-one (described in US Pat. No. 3,484,237), and 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 the same time, there is currently no material 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 transport material in the photosensitive layer, a copying machine with high sensitivity and excellent repeatability can be achieved. The purpose of the present invention is to provide an electrophotographic photoreceptor for use in cameras 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 hydrazone compound represented by either of the following general formulas (I) and (II). shall be.

[In formulas (1) and (■), R1, R2, Rs, R
s and R7 are each a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a hydroxy group, or an acyl group.

It represents a nitro group, an optionally substituted aryl group, or an amino group, and R2 and R6 represent an optionally substituted aryl group.

Further, n represents either 1 or 2. ] [Function] There is no known example in which a hydrazone compound represented by either of the above general formulas (I) or (II) 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 either of the above general formulas (I) or (II) as a charge transporting substance is extremely effective in improving electrophotographic properties, and has been repeatedly carried out with high sensitivity. A photoreceptor with excellent characteristics has been obtained.

〔Example〕

The hydrazone compound of any of the general formulas (I) and <II) 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.

A specific example of the hydrazone compound represented by either of the general formulas (1) or (II) obtained in this way is exemplified by the exemplified compound N.
91 Edition 4 Sitting 5 Compound N96 Compound Teeth 11 Sitting 13 Sitting 15 Compound N916 Compound N921 The photoreceptor of the present invention contains the above-mentioned hydrazone compound in the photosensitive layer, but how to apply these hydrazone compounds. According to Fig. 1.

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 1. ) 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 in FIG.

The reason for using the two types of layer configurations shown in Figures 2 and 3 is that even if the layer configuration shown in Figure 2, which is normally used for a negative charging system, is used for a positive charging system, a charge transport material that is compatible with the layer configuration shown in Figure 2 cannot be used for a positive charging system. This is because the layer structure shown in FIG. 3 is required for a positive charging type photoreceptor at this stage.

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 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 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, 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 transport substance or the like may be added thereto.

As the resin binder, polycarbonate, polyester, polyamide, polyurethane, epoxy 2 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 either of the above-mentioned patterns (I) and (II) is dispersed as an organic charge transport substance in a resin binder, and is photosensitive as an insulating layer in a dark place. It functions to hold the body's charge and transport the charge injected from the charge generation layer when receiving light. 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, 5
It is also possible to use a combination of assembly materials such as i02 and materials that reduce electrical resistance such as metals and metal oxides. The coating material is not limited to organic insulating film forming materials (inorganic materials such as Si02, metals, metal oxides, etc. can also be formed by methods such as vapor deposition and sputtering.The coating material is 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 A polyester resin (
A coating solution was prepared by kneading 100 parts by weight (trade name: Vylon 200: manufactured by Toyobo) and a tetrahydrofuran (THF) solvent for 3 hours in a mixer, and then coated on an aluminum-deposited polyester film (8N-PET), which is a conductive substrate. A photosensitive layer was formed by coating using a wire bar method so that the film thickness after drying was 15 μm, and a photosensitive member having the structure shown in FIG. 1 was prepared.

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 mixture was pulverized for 20 minutes using an electromagnetic pulverizer (trade name: LIMMAC, manufactured by Fuji Electric) for pulverization. 1 part by weight of this finely powdered sample (!: 50 parts by weight of DMF (N,N-dimethylformamide) solvent) was subjected to ultrasonic dispersion treatment.Then, the sample and DMF were separated and filtered, and dried. Processing of metal-free phthalocyanine was carried out.

Next, 100 parts by weight of the hydrazone compound represented by the compound N11L2 was added to 700 parts by weight of tetrahydrofuran (THF).
7 parts by weight of the solution and 100 parts by weight of polymethyl methacrylate polymer (PMMA: manufactured by Tokyo Kasei) were mixed with 7 parts by weight of toluene.
A coating solution prepared by mixing a solution of 0.00 parts by weight was applied onto an aluminum vapor-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. On the charge transport layer thus obtained, 50 parts by weight of the above-treated metal-free phthalocyanine, 50 parts by weight of polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.), and 50 parts by weight of PMM A were added together with a THF solvent. Knead with a mixer for 3 hours to adjust the coating solution,
A charge generation layer was formed by coating using a wire bar method so that the film thickness after drying was 1 μm, and a photoreceptor having 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) 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 chlorodiambre, which is a suazo pigment, as shown in JP-A-47-37543, instead of metal-free phthalocyanine, and a photoreceptor was formed. Created.

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 of the photoreceptor (volts) is +6. OkV
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.
Measure a (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 V to be halved, and calculate the half-attenuation exposure amount E1/2 (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.
The electrophotographic characteristics when using 0 nm monochromatic light were also measured at the same time.In other words, measurements were made in the same way up to V6, and then 1 μ-monochromatic light (780 nm) was irradiated instead of white light. The half-attenuation exposure amount (μJ/cIIl) is calculated using
r (volts) was measured. The measurement results are shown in Table 1.

Table 1 As seen in Table 1, Example 1. 2.3°4 has comparable half-attenuation exposure and residual potential, and also exhibits good characteristics in terms of surface potential.

Furthermore, Examples 1 and 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 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 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,tIkV for 0.2 seconds, V = -620V.

Vr”-40V, E l/2 =4.9 Roux/
Good results were obtained in seconds.

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 together with T I (F solvent) in a mixer for 3 hours. 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, 100 parts by weight of a hydrazone compound represented by compound Nα5 and a polycarbonate resin (
Panlite L-1250) 100 parts by weight, 0.1 parts by weight of silicone oil, 700 parts by weight of THF and 700 parts by weight of toluene.
They were mixed in parts by weight and coated on the charge generation layer to a thickness of about 15 μm to form a charge transport layer.

When the photoreceptor thus obtained was corona charged at -6, OkV for 0.2 seconds in the same manner as in Example 5, Vs' = -650V, E l/2 ='6.6 Lux.・Good results were obtained in seconds.

Example 7 Charge generation layers were prepared in the same manner as in Example 4 for each of Compounds Nα6 to No. 21 and measured using rSP-428J. Table 2 shows the results. This result is + in the dark.
6. Corona discharge at OkV was performed for 10 seconds to positively charge the sample, and the half-attenuation exposure mE+y□ (lux/second) was shown when white light with an illuminance of 2 lux was irradiated.

Table 2 As seen in Table 2, the hydrazone compound Nα6
The half-attenuation exposure amount El/2 was also good for the photoreceptor using ~Nα21 as the charge transport material.

〔Effect of the invention〕

According to the present invention, since the hydrazone compound represented by either of the above-mentioned patterns (I) and (n) is used as a charge transport substance on a conductive substrate, it is highly sensitive even in positive and negative charging. Moreover, a photoreceptor with excellent repeatability characteristics can be obtained.

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 material, 6 charge transport layer, 7 coating layer, 20.
21.22 Photosensitive layer. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one hydrazone compound represented by either of the following general formulas (I) and (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・(
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・(I
I) [R_1, R_2, R_3 in formulas (I) and (II)
, R_4 and R_7 each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a hydroxy group, an acyl group, a nitro group, an optionally substituted aryl group, and an amino group, and R_5 and R_6 represent an optionally substituted aryl group. represents a group. Further, n represents either 1 or 2. ]