JPS63158556A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body high in sensitivity and superior in characteristics resisting to repeated uses by incorporating a specified ethylenic compound in a photosensitive layer formed on an electric conductive substrate. CONSTITUTION:The photosensitive layer formed on the electric conductive substrate comprises an electric charge generating material and as a charge transfer material at least one of the ethylenic compounds represented by formula I in which each of R1-R12 is H, halogen, OH, alkyl, alkoxy, allyl, carboxy, ester, aryl, cyano, nitro, amino, alkylamino, or arylamino, and each of R13 and R14 is H, lower alkyl, or aryl, thus permitting the obtained photosensitive body to be high in sensitivity even in the case of positive and negative charging, and superior in repeated use characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more specifically, in a photosensitive layer formed on a conductive substrate, a compound having the general formula (r) represented by nr)
The present invention relates to an electrophotographic photoreceptor characterized by containing an ethylene compound represented by:

[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. Dispersed, Po I
Organic photoconductive substances such as JN-vinylcarbazole or polyvinylanthracene, organic photoconductive substances such as phthalocyanine compounds or bisazo compounds, or these organic photoconductive substances dispersed in a resin binder are used. ing.

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, but these functions can be achieved in one layer. It has a so-called single-layer type photoreceptor that has both functions, and a layer that is functionally separated into a layer that mainly contributes to charge generation, a layer that contributes to surface charge in the dark, and a layer that contributes to charge transport during light reception. ) There is a so-called bond layer 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 an electrostatic latent image such as text or pictures on the original on the surface of the charged photoconductor, and forming an electrostatic latent image on the surface of the charged photoconductor. After the toner image has been transferred, the photoreceptor is subjected to static electricity removal, removal of residual toner, photostatic static removal, etc. before being reused. be done.

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
．． 4.7-) dinitrofluoren-9-one (described in US 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, it is currently not possible to obtain a material that satisfactorily satisfies all the characteristics required of an electrophotographic photoreceptor, especially in terms of photosensitivity and There was a problem with the characteristics when used repeatedly and continuously.

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 ethylene compound represented by the following general formula (I).

(In formula (I), R1 to R1□ are each a hydrogen atom, a halogen atom, a hydroxy group, an alkyl group, an alkoxy group,
Allyl group, carboxyl group, ester group.

Represents an aryl group, cyano group, nitro group, amino group, alkylamino group or arylamino group.

R13+ R14 represents a hydrogen atom, a lower alkyl group or an aryl group. ) [Function] The synthesis method of the ethylene compound of the above general formula used in the present invention is described in the literature.

However, there are no known examples of using these ethylene compounds in photosensitive layers. In order to achieve the above object, the present inventors conducted a number of experiments on these ethylene compounds while conducting intensive studies on various organic materials. By using such an ethylene compound represented by the general formula (I) as a charge transporting substance in the photosensitive layer,
They discovered that a photoreceptor with high sensitivity and excellent repeatability can be obtained.

〔Example〕

Specific examples of the ethylene compound represented by the general formula (I) used in the present invention are as follows.

The photoreceptor of the present invention contains the above-mentioned ethylene compound in the photosensitive layer, and depending on the application of these ethylene compounds, the photoreceptor may be used as shown in FIG. 1, FIG. 2, or FIG. 3. be able to.

1 to 3 are conceptual cross-sectional views of different embodiments of the photoreceptor of the present invention, in which 1 is a conductive substrate, 3 is a charge-generating material, 4 is a charge-generating layer, and 5 is ? 6 is a charge transporting layer, 7 is a coating layer, and 20.21°22 is a photosensitive layer.

FIG. 1 shows a photosensitive layer 20 (usually called a single-layer photoreceptor) in which a charge-generating substance 3 and an ethylene compound as a charge-transporting substance 5 are dispersed in a resin binder on a conductive substrate 1. This configuration is equipped with the following configuration.

FIG. 2 shows a photosensitive layer 2 formed by laminating a charge generation layer 4 mainly containing a charge generation substance 3 and a charge transport layer 6 containing an ethylene 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, a covering layer 7 is generally provided to protect the charge generation layer 4.

The reason for the two types of layer configurations shown in FIGS. 2 and 3 is that the photoreceptor is used in a positive charging system or a negative charging system, and the layer configuration shown in FIG. 2 is usually used in a negative charging system. Even if you try to use the positive charging method with the layer configuration shown in Figure 2,
At present, no charge-transporting substance has been found that meets this requirement. Therefore, as the present inventors have already proposed, the layer structure shown in Figure 3 is considered to be effective as a positive charging type photoreceptor. It can be mentioned.

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 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 particles of the charge-generating substance in a solvent. Alternatively, 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 generation efficiency is high, and at the same time, the generated charges are dispersed in the charge transport layer 6 and the coating layer 7.
It is important to have good injection properties even in low electric fields with little dependence on electric fields. As the charge generating substance, phthalonanine compounds such as metal-free phthalonanine and titanyl phthalocyanine, various azo, quinone, and indigo pigments, or selenium or selenium compounds are used, depending on the light wavelength range of the exposure light source used for image formation. A suitable material can be selected. 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 an ethylene 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 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 for the surface charge to be neutralized and annihilated by the injection of the generated charge. 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, 5i
It is also possible to use a mixture of an inorganic material such as n2, or a material that reduces electrical resistance such as a metal or metal oxide. The coating material is not limited to organic insulating film-forming materials, and may also be formed of inorganic materials such as SiO□, metals, metal oxides, etc. by methods such as vapor deposition and spankling. 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 50 parts by weight of gold-free phthalonanine (manufactured by Tokyo Kasei Co., Ltd.) ground for 150 hours in a ball mill and 100 parts by weight of the ethylene compound represented by the compound Nαl were mixed with 100 parts by weight of a polyester resin (Vylon manufactured by Toyobo Co., Ltd.) and tetrahydrofuran (THF). ) Prepare a coating solution by kneading it with a solvent in a mixer for 3 hours, and apply it on a conductive substrate, aluminum vapor-deposited polyester film (A A-PET), using a wire bar method to determine the film thickness after drying. A photoreceptor was prepared by forming a photosensitive layer so that the thickness of the photoreceptor was 15 μm.

Example 2 First, α-type metal-free phthalocyanine is used as a starting material, and between two linear motors placed opposite to 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. Ultrasonic dispersion treatment was performed on 1 weight fm of this finely powdered sample and 50 parts by weight of DMF (N,N-dimethylformamide) solvent.

Thereafter, the sample and DMF were separated and filtered, dried, and treated for metal-free phthalocyanine.

Next, a solution prepared by dissolving 100 parts by weight of the ethylene compound represented by the compound N (L l) in 700 parts by weight of tetrahydrofuran (THF) and a polymethyl methacrylate polymer (
PMMA: Tokyo Kasei) 100 parts by weight to 700 parts by weight of toluene
A coating solution prepared by mixing parts by weight of the solution was applied onto an aluminum-deposited polyester film substrate using a wire bar to form a charge transport layer so that the film thickness after drying was 15 μm. On the thus obtained charge transport layer, 50 layers of metal-free phthalocyanine treated as described above and 50 layers of polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) are placed.
Part by weight, 50 parts by weight of PMMA and THF solvent were kneaded in a mixer for 3 hours to prepare a coating solution, which was coated with a wire bar to form a charge generation layer so that the film thickness after drying was 1 μm, and then exposed to light. The body was created.

Example 3 The composition of the photosensitive layer of Example 1 was changed to 50% metal-free phthalocyanine.
Parts by weight, 100 weight of ethylene compound expressed as compound kl! A photosensitive layer was formed in the same manner as in Example 1, except that 50 parts by weight of polyester resin (trade name: Vylon 200, 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 bisazo pigment as disclosed in JP-A-47-37543, instead of metal-free phthalocyanine, and a photoreceptor was produced. 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 (volts) of the photoreceptor is the initial surface potential when +6.0H corona discharge is performed in a dark place for 10 seconds to positively charge the photoreceptor surface, and then when the corona discharge is stopped. The surface potential Vd (
volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux to find the time (seconds) for V,+ to be halved, and calculate the half-attenuation exposure amount E1/2 (lux seconds).
And so. 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 can be expected with long wavelength light, so the wavelength is 780 r.
At the same time, electrophotographic characteristics were measured using in monochromatic light. That is, measure up to vd in the same way, then irradiate 1μ gastric monochromatic light (780nm>) instead of white light to determine the half-attenuation exposure (μJ/cd), and apply this light to the photoreceptor for 10 seconds. The residual potential vr (volts) when the surface was irradiated was measured.The measurement results are shown in Table 1.

Table 1 As seen in Table 1, Examples 1.2.3.4 had good half-attenuation exposure and residual potential.

Example 5 Selenium was deposited to a thickness of 1 on a 500 μm thick aluminum plate.
, 5 μm to form a charge generation layer, and then 100 parts by weight of an ethylene compound represented by compound Nα2 was dissolved in 70 parts of tetrahydrofuran (THF) and polymethyl methacrylate polymer (PMMA).
A coating solution prepared by mixing 100 parts by weight of Tokyo Kasei) with 700 parts by weight of toluene was applied using a wire bar to form a charge transport layer so that the film thickness after drying was 20 μm. A corona charge of -6,0kV is applied to this photoreceptor.
．． When the test was carried out for 2 seconds and the characteristics were measured according to Example 4, Vs=~700V, V.

=-100V, voltage =/-=5.1 lux·sec, and good results were obtained.

Example 6 50 parts by weight of metal-free phthalonanine treated in Example 1, 50 parts by weight of polyester resin (trade name: Vylon 200 manufactured by Toyobo), 50 parts by weight of PMMA and THF solvent were kneaded in a mixer for 3 hours to prepare a coating solution. The mixture was adjusted 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 an ethylene compound represented by compound Nα3, 100 parts by weight of polycarbonate resin (Panlite L-1250), 0.1 part by weight of silico oil, 700 parts by weight of THF and 70 parts by weight of toluene were added.
The mixture was mixed at 0 parts by weight and coated on the charge generation layer to a thickness of about 15 μm to form a charge transport layer to produce a photoreceptor.

The photoreceptor thus obtained was corona charged at -5, QkV for 0.2 seconds in the same manner as in Example 5, and the characteristics were measured: V-=-810V, B1/2 = 5
．． A good result of 8 lux·sec was obtained.

Example 7 Same as Example 4 for each of compounds Nα4 to 14,
A photoreceptor was prepared by forming a photosensitive layer, and its properties were measured using "RSP-428". The results are shown in Table 2.

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

As shown in Table 2, it can be seen that a good half-attenuation exposure amount can be obtained also in the photoreceptor using the compounds Hiroshi 4 to Nα14.

Table 2 [Effects of the Invention] According to the present invention, since the ethylene compound represented by the general formula (I) is used as the charge transporting substance of the photosensitive layer provided on the conductive substrate, positive charging and negative charging are possible. It is also possible to obtain a photoreceptor with high sensitivity and excellent repeatability. 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 the durable pressure.

[Brief explanation of the drawing]

1.2.3 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, 2
0.21.22 Photosensitive layer. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor characterized by having a photosensitive layer containing at least one kind of ethylene compound represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In formula (I), R_ to R_1_2 are hydrogen atoms, halogen atoms, hydroxy groups, alkyl groups, alkoxy groups, allyl groups, carboxyl groups, and esters, respectively. group, aryl group, cyano group, nitro group, amino group, alkylamino group, or arylamino group. R_1_3 and R_1_4 represent a hydrogen atom, a lower alkyl group, or an aryl group.)