JPH04304465A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the electrophotographic sensitive body having a high sensitivity and excellent repetitive characteristics by incorporating a specific amine compd. as a charge transfer material into a photosensitive layer. CONSTITUTION:The photosensitive layer 21 consisting of the laminated layers of a charge generating layer 4 essentially consisting of a charge generating material and a charge transfer layer 6 contg. the specific amine compd. which is the charge transfer material on a conductive substrate 1. In the formula, A denotes a substd. or unsubstd. heterocyclic group contg. atoms of at least one kind among a nitrogen atom, oxygen atom and sulfur atom; R1 to R6 respectively denote a substd. or unsubstd. alkyl group, aryl group or arom. heterocyclic group. The photosensitive body having the high sensitivity and the excellent repetitive characteristics even in positive charge and negative charge is obtd. in this way. Adequate materials are selectable in correspondence to the kinds of exposing light sources for the charge generating material; for example, the photosensitive body suitable for a semiconductor laser printer is obtd. if a phthalocyanine compd. and squalilium compd., etc., are used.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a photosensitive layer of an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a novel charge transport material.

0002

[Prior Art] 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, and inorganic photoconductive substances such as zinc oxide or cadmium sulfide. dispersion in a binder, an organic photoconductive material such as poly-N-vinylcarbazole or polyvinylanthracene, a dispersion of an organic photoconductive material such as a phthalocyanine compound or a bisazo compound in a resin binder; or vacuum-deposited materials are used.

[0003]Also, a photoreceptor must have the function of retaining a surface charge in the dark, the function of receiving light and generating a charge, and the function of receiving light and transporting a charge. So-called single-layer photoreceptors have these functions in one layer, and the other is a layer that is functionally separated into 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 type photoreceptor in which two types of photoreceptors are laminated. 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.

[0004] In recent years, many applications of photoconductive organic compounds with excellent charge transport ability to photoreceptors have been proposed due to their advantages such as flexibility, thermal stability, and film-forming properties. For example, as an oxadiazole compound, US Pat. No. 318,944
Specification No. 7, as a pyrazoline compound, Japanese Patent Publication No. 59-2
No. 023, and as a hydrazone compound, Japanese Patent Publication No. 5
Various charge transport materials are known from Japanese Patent Application Laid-open No. 5-42380, Japanese Patent Application Laid-Open No. 57-101844, Japanese Patent Application Laid-Open No. 54-150128, etc.

[0005]

[Problems 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, it is difficult to obtain a material that fully satisfies all the characteristics required of an electrophotographic photoreceptor. Currently, there are no such devices, and there are problems with sensitivity 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, high sensitivity and excellent repeatability can be achieved. The purpose of the present invention is to provide an electrophotographic photoreceptor for copying machines and printers.

[0007]

[Means for Solving the Problems] According to the present invention, the above-mentioned object has a photosensitive layer on a conductive substrate, and the photosensitive layer contains an amine compound of general chemical formula (I) or general chemical formula (II) as a charge transporting substance. This is achieved by including it as

[0008]

[Chemical formula 3]

(In the formula, A represents a substituted or unsubstituted heterocyclic group containing at least one kind of atom among nitrogen atom, oxygen atom, and sulfur atom, and R1, R2, R3
, R4, R5, R6 are each substituted or unsubstituted alkyl group, aryl group, or aromatic heterocyclic group,
represents. )

0010

[Operation] There is no known example of using an amine compound represented by the general chemical formula (I) or (II) in a photosensitive layer. In order to achieve the above object, the present inventors conducted a number of experiments on these amine compounds while intensively studying various organic materials. The above general chemical formula (
It has been discovered that the use of an amine compound having a specific skeleton represented by I) or (II) as a charge transport material 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.

[0011]

[Example] Specific examples of the amine compounds represented by the general chemical formula (I) or (II) used in the present invention are shown in Tables 1 to 1.
It is shown in Table 8. Their chemical formulas are I-1 to I-80 and II-1 to II-80.

0012

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[0015]

[Table 4]

[0016]

[Table 5]

[0017]

[Table 6]

[0018]

[Table 7]

[0019]

[Table 8]

[0020] Next, examples of synthesis of the above compound are as follows. That is, the diamine compound of chemical formula I-12 is 2,5-bis(4'-diaminophenyl)-
It can be obtained by adding 1,4-dithiine to iodobenzene, adding potassium carbonate in an amount 4.2 times the mole of the raw material amine, and a catalytic amount of copper powder, heating to reflux, and then performing a usual post-treatment. Moreover, the amine compound of chemical formula II-14 is 2-phenyl-5-aminophenyl-1,4-
It can be obtained by adding dithiin to iodotoluene, adding potassium carbonate in an amount 2.1 times the mole of the raw material amine, and a catalytic amount of copper powder, heating to reflux, and then performing a usual post-treatment. Furthermore, compounds other than the above synthesis examples can also be synthesized by similar methods or known methods.

The photoreceptor of the present invention contains the above-mentioned amine compounds in the photosensitive layer, and depending on the application of these amine compounds, the photoreceptor shown in FIG. 1, FIG. 2, or FIG.
It can be used as shown in

1 to 3 are conceptual cross-sectional views of the photoreceptor of the present invention, in which 1 is a conductive substrate, 20, 21, 22 are photosensitive layers, and 3
is a charge generation material, 4 is a charge generation layer, 5 is a charge transport material,
6 is a charge transport layer, and 7 is a coating layer.

FIG. 1 shows a charge generating substance 3 on a conductive substrate 1.
A photosensitive layer 20 (commonly referred to as a single-layer photoreceptor) is provided in which an amine compound as a charge transport material 5 is dispersed in a resin binder.

FIG. 2 shows a charge generating substance 3 on a conductive substrate 1.
A photosensitive layer 21 (commonly referred to as a laminated photoreceptor) is provided, which is composed of a laminated layer of a charge generation layer 4 mainly composed of a charge-generating layer 4 and a charge-transporting layer 6 containing an amine compound as a charge-transporting substance 5. be.

FIG. 3 shows a layer structure opposite 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 FIGS. 2 and 3 is that even if the layer configuration shown in FIG. 2, which is normally used for a negative charging system, is used in a positive charging system, there is no compatible charge transport material. This is because the layer structure shown in FIG. 3 is required at this stage as a positive 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 applying this dispersion onto a conductive substrate.

The photoreceptor shown in FIG. 2 is prepared by vacuum-depositing a charge-generating substance on a conductive substrate, or by applying a dispersion obtained by dispersing particles of a charge-generating substance in a solvent or a resin binder, and drying it. It can be created by applying a solution containing a charge transport substance and a resin binder thereon and drying it.

The photoreceptor shown in FIG. 3 can be 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 applying particles of the charge generating substance. It can be created by dispersing the liquid in a solvent or a resin binder, coating the resulting dispersion, drying it, and further forming a coating layer.

The conductive substrate 1 serves as an electrode of 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, It may also be made of metal such as nickel, glass, resin, etc., 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 evaporation, and receives light to generate charges. occurs. In addition to the high charge generation efficiency, the ability to inject the generated charges into the charge transport layer 6 and the coating layer 7 is also important, and it is desirable that the charge is less dependent on the electric field and can be easily injected even in a low electric field. As charge-generating substances, phthalocyanine compounds such as metal-free phthalocyanine and titanyl phthalocyanine, various azo, quinone, and indigo pigments, dyes such as cyanine, squarylium, azulenium, and pyrylium compounds, and selenium or selenium compounds are used to form images. A suitable material can be selected depending on the light wavelength range of the exposure light source used. 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, appropriate combinations of polycarbonate, polyester, polyamide, polyurethane, vinyl chloride, phenoxy resin, polyvinyl butyral, epoxy, diallyl phthalate resin, silicone resin, methacrylic acid ester polymers and copolymers, etc. may be used. is possible.

The charge transport layer 6 is composed of the general chemical formula (I) or (II) as an organic charge transport substance in a resin binder.
) It is a coating film in which the amine compound represented by the formula (2) is dispersed, and it functions as an insulating layer in the dark to retain the charge on the photoreceptor, and when receiving light, it functions to transport the charge injected from the charge generation layer. As a resin binder, polycarbonate,
polyester, polyamide, polyurethane, epoxy,
Silicone resins, polymers and copolymers of methacrylic acid esters, etc. can be used.

The coating layer 7 has the function of receiving and retaining the charges 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.
It is necessary to allow the charge to reach the charge generation layer and receive the generated charge to neutralize and eliminate the surface charge. As the coating material, organic insulating film-forming materials such as polyester and polyamide can be used. Further, these organic materials can be mixed with inorganic materials such as glass resin and SiO2, and materials that reduce electrical resistance such as metals and metal oxides. The coating material is not limited to organic insulating film forming materials, and may also be formed of inorganic materials such as SiO2, metals, metal oxides, etc. by methods such as vapor deposition and 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 any adverse effects such as an increase in residual potential when used repeatedly and continuously.

Example 1x type metal-free phthalocyanine (H2
Pc) 50 parts by weight and 100 parts by weight of the amine compound represented by the above chemical formula I-1 were kneaded together with 100 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo) and a tetrahydrofuran (THF) solvent using a mixer for 3 hours and applied. A photoreceptor was prepared by adjusting the solution and coating it on an aluminum-deposited polyester film (Al-PET), which was a conductive substrate, by a wire bar method so that the film thickness after drying was 15 μm.

Example 2 80 parts by weight of the amine compound represented by the chemical formula I-2 and a polycarbonate resin (trade name Panlite L-1225)
A coating liquid prepared by dissolving 100 parts by weight of (manufactured by Teijin Kasei) in methylene chloride is applied onto an aluminum vapor-deposited polyester film substrate using a wire bar to form a charge transport layer so that the film thickness after drying is 15 μm. did. On the thus obtained charge transport layer, 50 parts by weight of titanyl phthalocyanine (TiOPc) which had been pulverized for 150 hours in a ball mill, 50 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo), and a THF solvent were mixed for 3 hours. A coating solution was prepared by kneading with a machine, and applied with a wire bar to form a charge generation layer having a thickness of 1 μm after drying.

Example 3 Photosensitization was carried out in the same manner as in Example 2, except that TiOPc was replaced with a squarylium compound represented by the following structural formula, and the charge transport substance was replaced with an amine compound represented by the chemical formula I-3. The body was created.

[0038]

[C4]

Example 4 In Example 2, instead of TiOPc, for example,
A photoreceptor was prepared in the same manner as in Example 2 using chlorodiane blue, a bisazo pigment shown in No. 7-37543, and changing the charge transport material to the amine compound shown by the chemical formula I-4.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester "SP-428" manufactured by Kawaguchi Electric.
Measured using Photoreceptor surface potential VS (volts)
is the initial surface potential when +6.0 kV corona discharge is performed in the dark for 10 seconds to positively charge the photoreceptor surface, and the surface potential is then maintained in the dark for 2 seconds with corona discharge stopped. Measure the potential Vd (volts), and then irradiate the surface of the photoreceptor with white light with an illuminance of 2 lux to determine the voltage Vd.
The time (seconds) required for d to be halved was determined and defined as 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, for Examples 1 to 3, high sensitivity with long wavelength light can be expected, so wavelength 7
Electrophotographic properties using 80 nm monochromatic light were also measured at the same time. That is, measurements were made in the same manner up to Vd, and then 1 μW monochromatic light (780 nm) was irradiated instead of white light to determine the half-attenuation exposure amount (μJ/cm2), and
The residual potential Vr (volts) when the surface of the photoreceptor was irradiated with this light for 10 seconds was measured. The measurement results are shown in Table 9.

[0041]

[Table 9]

As seen in Table 9, Examples 1, 2, and 3
, 4 are comparable in both half-attenuation exposure and residual potential, and also exhibit good characteristics in terms of surface potential. In addition, Example 1
It can be seen that samples 3 to 3 show high sensitivity even to long wavelength light of 780 nm, and can 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 100 parts by weight of an amine compound represented by the chemical formula II-1 and 1 part of polycarbonate resin (PCZ200: manufactured by Mitsubishi Gas Chemical) were added.
A coating liquid prepared by dissolving 00 parts by weight in methylene chloride was applied using a wire bar to form a charge transport layer so that the film thickness after drying was 20 μm. In this photoreceptor, V
S=-650V, Vr=-25, E1/2=1.4
Good results were obtained in terms of looks and seconds.

Example 6 In the same manner as in Example 2, 50 parts by weight of x-type metal-free phthalocyanine 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. A coating solution was prepared and coated onto an aluminum support to a thickness of about 1 μm to form a charge generation layer. Next, amine compound 100 represented by chemical formula II-2
Parts by weight, polycarbonate resin (Panlite L-125
0), 100 parts by weight of silicone oil and 0.1 parts by weight of silicone oil were mixed with methylene chloride, and the mixture was coated on the charge generation layer to a thickness of about 15 μm to form a charge transport layer. In the photoreceptor thus obtained, VS = -680V, E1
/2 = 1.1 lux·sec, a good result was obtained.

Example 7 The same procedure as in Example 6 was carried out except that a bisazo pigment represented by the following structural formula was used instead of the metal-free phthalocyanine, and an amine compound represented by the chemical formula II-3 was used as the charge transport substance. A photoreceptor was created. In the photoreceptor thus obtained, VS = -630V, E1/2
= 1.7 lux·sec, a good result was obtained.

[0046]

[C5]

Example 8 Chemical formula I-5 to chemical formula I-80 and chemical formula II-
Photoreceptors were prepared in the same manner as in Example 4 for each of Formulas 4 to II-80 and measured using SP-428. The results are shown in Tables 10 and 11. +6.0k in the dark
Half-attenuation exposure amount E1/2 when corona discharge of V is performed for 10 seconds to positively charge, and white light with an illuminance of 2 lux is irradiated.
Expressed in (lux seconds).

[0048]

[Table 10]

[0049]

[Table 11]

As seen in Tables 10 and 11, amine compounds represented by chemical formulas I-5 to I-80 and amine compounds represented by chemical formulas II-4 to II-80 were used as charge transport materials. The half-attenuation exposure amount E1/2 of the photoreceptor was also good.

[0051]

Effects of the Invention According to the present invention, since the amine compound represented by the general chemical formula (I) or (II) is used as a charge transport substance on a conductive substrate, the sensitivity is high even in positive charging and negative charging. Moreover, a photoreceptor with excellent repeatability characteristics can be obtained. In addition, suitable charge-generating substances can be selected depending on the type of exposure light source. For example, phthalocyanine compounds, squarylium compounds, and certain bisazo compounds can be used as light-sensitive materials that can be used in semiconductor laser printers. You can get a body. Furthermore, if necessary, it is possible to provide a coating layer on the surface to improve durability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a single-layer photoconductor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a negatively charged laminated photoreceptor according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a positively charged laminated photoreceptor according to an embodiment of the present invention.

[Explanation of symbols]

1 Conductive substrate 3 Charge generating substance 4 Charge generation layer 5 Charge transport material 6 Charge transport layer 7 Coating layer 20 Photosensitive layer 21 Photosensitive layer 22 Photosensitive layer

Claims (9)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer on a conductive substrate, the photosensitive layer containing an amine compound represented by general chemical formula (I) as a charge transport substance. [Formula 1] (wherein A represents a substituted or unsubstituted heterocyclic group containing at least one kind of atom among nitrogen atom, oxygen atom, and sulfur atom, R1 , R2 , R3 and R4
each represents a substituted or unsubstituted alkyl group, aryl group, or aromatic heterocyclic group. ) 2. In the photoreceptor according to claim 1, the amine compound of general chemical formula (I) is R1 , R2 , R3 , R
An electrophotographic photoreceptor, wherein each of 4 is a CH3 group. 3. In the photoreceptor according to claim 1, in the amine compound of general chemical formula (I), R1 and R2 are each C
An electrophotographic photoreceptor, wherein each of the H3 group, R3, and R4 is a C2 H5 group. 4. In the photoreceptor according to claim 1, in the amine compound of general chemical formula (I), R1 and R2 are each C
An electrophotographic photoreceptor, wherein each of the H3 group, R3, and R4 is a phenyl group. 5. In the photoreceptor according to claim 1, in the amine compound of general chemical formula (I), R1 and R2 are each C
2 H5 group, R3 and R4 are each CH2 -C
An electrophotographic photoreceptor characterized by having a 6 H5 group. 6. An electrophotographic photoreceptor comprising a photosensitive layer on a conductive substrate, the photosensitive layer containing an amine compound of general chemical formula (II) as a charge transporting substance. [Chemical formula 2] (In the formula, A represents a substituted or unsubstituted heterocyclic group containing at least one kind of atom among a nitrogen atom, an oxygen atom, and a sulfur atom, and R5 and R6 are each a substituted or unsubstituted heterocyclic group. represents an alkyl group, aryl group, or aromatic heterocyclic group) 7. A photoreceptor for electrophotography according to claim 6, wherein in the amine compound of general chemical formula (II), R5 and R6 each represent a CH3 group. 8. In the photoreceptor according to claim 6, in the amine compound of general chemical formula (II), R5 is a CH3 group, R6
An electrophotographic photoreceptor, characterized in that is a C2 H5 group. 9. In the photoreceptor according to claim 6, in the amine compound of general chemical formula (II), R5 is a CH3 group, R6
An electrophotographic photoreceptor, characterized in that is a phenyl group.