JPH08292588A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE: To obtain a photoreceptor excellent in sensitivity and repetitive characteristics. CONSTITUTION: A distyryl compd. represented by formula I is used as an electric charge transferring material and a bisazo compd. represented by formula II is used as an electric charge generating material. In the formula I, each of R1 -R6 is H, an optionally substd. aryl or alkyl and the phenylene group has m- or o-arrangement. In the formula II, R7 is a halogen, alkyl or alkoxy, R8 is an optionally substd. alkyl, R9 is H, cyano, carbamoyl, carboxy, alkoxycarbonyl or acyl and R10 is H, a halogen, nitro, optionally substd. alkyl or alkoxy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoconductor used in electrophotographic printers, copying machines, and the like.
In particular, it relates to a charge generating substance and a charge transporting substance used for the photosensitive layer.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive material for an electrophotographic photoreceptor (hereinafter also referred to as a photoreceptor), an inorganic photoconductive substance such as selenium or a selenium alloy, or an inorganic photoconductive substance such as zinc oxide or cadmium sulfide is used as a resin. An organic photoconductive substance such as poly-N-vinylcarbazole or polyvinylanthracene dispersed in a binder, or an organic photoconductive substance such as a phthalocyanine compound or a bisazo compound is dispersed in a resin binder. The thing and the thing vapor-deposited by vacuum are used. In addition, the photoconductor needs to have the function of retaining surface charge in the dark, the function of receiving light to generate charge, and the function of receiving light to transport charge as well. A so-called laminated structure in which a so-called single-layer type photoreceptor having a combination of functions, a layer mainly functioning to generate charges and a layer function-separated into a layer contributing to retention of surface charges in a dark place and a charge transportation during light reception are laminated. There is a type photoconductor. For example, the Carlson method is applied to the image formation by the electrophotographic method using these photoconductors. Image formation by this method is charging by corona discharge to a photoconductor in a dark place, formation of an electrostatic latent image such as characters and pictures of an original on the charged surface of the photoconductor, electrostatic latent image formed Of the developed toner image and fixing of the developed toner image to a support such as paper.After the toner image has been transferred, the photoconductor is neutralized, residual toner is removed, and light is neutralized before reuse. To 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 property. For example, a photoreceptor composed of poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (described in US Pat. No. 3,484,237), a photoreceptor containing an organic pigment as a main component (special Kaisho 47
No. 37543), a photoconductor containing a eutectic complex composed of a dye and a resin as a main component (JP-A-47-10785).
No. publication).

[0004]

However, although organic materials have many advantages over inorganic materials, at the same time, none of them have sufficiently obtained all the properties required for electrophotographic photoreceptors. However, there is a strong demand for a photoreceptor having high sensitivity and excellent repeatability. The present invention has been made in view of the above points, and an object thereof is to provide an electrophotographic photoreceptor for a copying machine, which eliminates the above-mentioned drawbacks by a novel combination of a charge generating substance and a charge transporting substance and is excellent in sensitivity and repeatability. To aim.

[0005]

According to the first aspect of the present invention, there is provided a photosensitive layer on a conductive substrate, the photosensitive layer comprising a distyryl compound represented by the general formula (I) as a charge transporting substance. It contains a bisazo compound represented by the general formula (II) as a charge generating substance.

[0006]

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(R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or an alkyl group, and the phenylene group has meta or ortho coordination. .)

[0008]

[Chemical 9]

(R ₇ represents a halogen atom, an alkyl group or an alkoxy group, R ₈ represents an optionally substituted alkyl group, R ₉ represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxy group, an alkoxycarbonyl group or Represents an acyl group, and R ₁₀ represents a hydrogen atom, a halogen atom, a nitro group or an optionally substituted alkyl group, an alkoxy group.) According to the second invention, a photosensitive layer is provided on a conductive substrate,
The photosensitive layer contains a distyryl compound represented by the general formula (I) as a charge transport substance and a polycyclic quinone compound represented by the general formula (III) as a charge generation substance,

[0010]

[Chemical 10]

(R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or an alkyl group, and the phenylene group has meta or ortho coordination. .)

[0012]

[Chemical 11]

(X represents a hydrogen atom, a halogen atom or a cyano group, and n represents an integer of 0 to 4.) According to the third invention, a photosensitive layer is provided on a conductive substrate,
The photosensitive layer contains a distyryl compound represented by the general formula (I) as a charge transport substance and a squarylium compound represented by the general formula (IV) as a charge generation substance,

[0014]

[Chemical 12]

(R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or an alkyl group, and the phenylene group has a meta or ortho coordination. .)

[0016]

[Chemical 13]

(R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ are each an optionally substituted alkyl group, aryl group, aralkyl group,
An alkenyl group or R ₁₁ and R ₁₂ , or R ₁₃
And R ₁₄ can form a ring. R ₁₅ and R ₁₆ each represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group. According to the fourth invention, a photosensitive layer is provided on a conductive substrate, and the photosensitive layer contains a distyryl compound represented by the general formula (I) as a charge transporting substance and a metal-free phthalocyanine or titanyloxyphthalocyanine as a charge generating substance. To include,

[0018]

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(R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or alkyl group, and the phenylene group has meta or ortho coordination. Specific examples of the general formula (I) include the chemical formula I-1 to the chemical formula I-.
16, specific examples of the general formula (II) are represented by the chemical formulas II-1 to II-6, and specific examples of the general formula (III) are the chemical formulas III-1.
To Chemical Formula III-8 and specific examples of the general formula (IV) are shown in Chemical Formulas IV-1 to IV-8, respectively.

[0020]

[Chemical 15]

[0021]

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[0022]

[Chemical 17]

[0023]

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[0024]

[Chemical 19]

[0025]

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[0026]

By the novel combination of the charge transport material and the charge generating material, it is possible to obtain a photosensitive member having high sensitivity and excellent repeating characteristics.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a negative charging type electrophotographic photosensitive member according to an embodiment of the present invention. 2 is a cross-sectional view showing a positive charging type electrophotographic photoreceptor according to an embodiment of the present invention. 1
Is a conductive substrate, 2 is a charge generation layer, 3 is a charge transport layer, 4 is a photosensitive layer, 5 is a surface coating layer, and the photosensitive layer is a function separation type in which a charge generation layer and a charge transport layer are separated. The photosensitive layer of FIG. 1 is a negative charging type in which a charge generating layer and a charge transporting layer are laminated in this order, and the photosensitive layer of FIG. 2 is a positive charging type in which the charge transporting layer and a charge generating layer are laminated in the opposite order to FIG. Is.

The conductive substrate 1 serves not only as an electrode of the photoconductor but also as a support for each of the other layers, and may be cylindrical, plate-shaped, or film-shaped, and made of aluminum, stainless steel, A metal such as nickel, glass, resin, or the like that has been subjected to a conductive treatment may be used.
The charge generation layer 2 is formed by vacuum vapor deposition of an organic photoconductive substance or by coating a material in which particles of an organic photoconductive substance are dispersed in a resin binder, and receives light to generate charges.
In addition, it is desirable that the charge generation efficiency is high, and at the same time, the property of injecting the generated charges into the charge transport layer 3 is important, the electric field dependency is small, and the injection is good even in a low electric field.

Since the charge generating layer has only to have a charge generating function, its thickness is determined by the light absorption coefficient of the charge generating substance and is generally 5 μm or less, preferably 1 μm or less. The charge generation layer may be mainly composed of a charge generation material and a charge transport material may be added to the charge generation layer. As the resin binder, it is possible to appropriately combine and use polycarbonate, polyester, polyamide, polyurethane, polyamitide, polyurethane, epoxy, polyvinyl butyral, phenoxy, silicone resin, methacrylic acid ester polymers and copolymers, and the like. .

The charge transporting layer 3 is a coating film made of a material in which an organic charge transporting substance is dispersed in a resin binder. The charge transporting layer 3 holds an electric charge of the photoconductor as an insulating layer in a dark place, and from the charge generating layer at the time of receiving light. It exerts the function of transporting the injected charges. Polymers and copolymers of polycarbonate, polyester, polystyrene, methacrylic acid ester, etc. are used as the resin binder. In addition to mechanical, chemical and electrical stability, adhesion, etc. Solubility is important.

The thickness of the charge transport layer is preferably in the range of 3 to 50 μm in order to maintain a practically effective surface potential.
More preferably, it is 10 to 40 μm. The surface coating layer 5 is excellent in durability against mechanical stress and is composed of a chemically stable substance. It has a function of receiving and holding a corona discharge charge in a dark place, and the charge generation layer is It is necessary to have a property of transmitting sensitive light, to transmit light at the time of exposure, to reach the charge generation layer, and to inject the generated charge to neutralize and eliminate the surface charge. Further, as described above, it is desirable that the coating material is as transparent as possible in the wavelength region where the light absorption maximum of the charge generating substance is maximized.

As a coating material for the surface coating layer, a modified silicone resin such as an acrylic modified silicone resin, an epoxy modified silicone resin, an alkyd modified silicone resin, a polyester modified silicone resin, a urethane modified silicone resin, or the like, or a hard coating agent is used. Silicon resin, etc. can be applied. These modified silicone resins can be used alone, but SiO ₂ and Ti are used for the purpose of improving durability.
A mixed material with a condensate of a metal alkoxy compound capable of forming a film containing O ₂ , In ₂ O ₃ and ZrO ₂ as a main component is preferable.

The film thickness of the coating layer itself depends on the composition of the coating layer, but can be arbitrarily set within a range that does not cause adverse effects such as increase in residual potential when repeatedly and continuously used. Example 1 1 part by weight of the bisazo compound represented by the chemical formula II-1 as a charge generating substance, and diallylphthalate as a binder resin.
1 part by weight of a resin (trade name DAP K: manufactured by Osaka Soda) and 150 parts by weight of methyl ethyl ketone are mixed and kneaded with a mixer for 3 hours to prepare a coating solution to prepare a coating solution for a charge generation layer. did. Next, 1 part by weight of the distyryl compound represented by the chemical formula I-8 as a charge transport material and a polycarbonate resin (trade name: Panlite L as a binder resin).
-1225: Teijin Kasei) 1 part by weight was dissolved in 6 parts by weight of dichloromethane to prepare a coating liquid for the charge transport layer. Next, polyester terephthalate vapor-deposited with aluminum.
Charge generation layer (1 μm), charge transport layer (2
The coating liquids prepared in the order of 0 μm) were applied to prepare a negative charging photoreceptor.

Example 2 A photoconductor was prepared in the same manner as in Example 1, except that the charge transporting material of Example 1 was replaced with the compound represented by the chemical formula I-9. Example 3 A photoconductor was prepared in the same manner as in Example 1 except that the charge transport material of Example 1 was replaced with the compound represented by the chemical formula I-16.

Example 4 A photoconductor was prepared in the same manner as in Example 1 except that the polycyclic quinone compound represented by the chemical formula III-4 was used instead of the charge generating substance in Example 1. Example 5 A photoconductor was prepared in the same manner as in Example 2, except that the polycyclic quinone compound represented by the chemical formula III-4 was used instead of the charge generating substance of Example 2.

Example 6 A photoconductor was prepared in the same manner as in Example 3 except that the polycyclic quinone compound represented by the chemical formula III-4 was used instead of the charge generating substance in Example 3. Example 7 A photoconductor was prepared in the same manner as in Example 1 except that the charge generating material of Example 1 was replaced with the squarylium compound represented by the chemical formula IV-8.

Example 8 A photoconductor was prepared in the same manner as in Example 2 except that the charge generating substance of Example 2 was replaced with the squarylium compound represented by the chemical formula IV-8. Example 9 A photoconductor was prepared in the same manner as in Example 3, except that the charge generating material of Example 3 was replaced with the squarylium compound represented by the chemical formula IV-8.

Example 10 A charge generating layer coating solution and a charge transporting layer coating solution were prepared in the same manner as in Example 1, and the charge transporting layer (20 μm) and the charge generating layer (1 μm) were applied in this order and positively charged. Was prepared as a photoreceptor. Comparative Example 1 A photoconductor was prepared in the same manner as in Example 1 except that 1-phenyl-3- (P-diethylaminostyryl) -5- (paradiethylaminophenyl) -2-pyrazoline (ASPP) was used as the charge transport material in Example 1. It was created.

Comparative Example 2 A photoconductor was prepared in the same manner as in Example 1 except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Example 1. Comparative Example 3 The same procedure as in Example 4 was repeated except that 1-phenyl-3- (P-diethylaminostyryl) -5- (paradiethylaminophenyl) -2-pyrazoline (ASPP) was used as the charge transport material in Example 4. It was created.

Comparative Example 4 A photoconductor was prepared in the same manner as in Example 4 except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Example 4. Comparative Example 5 A photoconductor was prepared in the same manner as in Example 7, except that 1-phenyl-3- (P-diethylaminostyryl) -5- (paradiethylaminophenyl) -2-pyrazoline (ASPP) was used as the charge transport material in Example 7. It was created.

Comparative Example 6 A photoconductor was prepared in the same manner as in Example 7 except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Example 7. Comparative Example 7 A charge generation layer coating solution and a charge transport layer coating solution were prepared in the same manner as in Comparative Example 1, and the charge transport layer (20 μm) and the charge generation layer (1 μm) were applied in this order, and the photosensitive layer for positive charging was exposed. The body was prepared.

Comparative Example 8 A photoconductor was prepared in the same manner as in Example 1, except that the charge generating substance in Example 1 was replaced with chlorodian blue. The electrophotographic characteristics of the photoconductor thus obtained were measured by using an electrostatic recording paper test device “SP-428” manufactured by Kawaguchi Electric.

The surface potential V _S (V) of the photoconductor is − in a dark place.
The initial surface potential when the surface of the photoconductor was negatively or positively charged by performing corona discharge of 6.0 kV or +6.0 kV for 10 seconds, and then kept in the dark for 2 seconds while the corona discharge was stopped. The surface potential V _D (V) at that time is measured, and then the time (s) until V _D becomes half by irradiating the surface of the photoconductor with white light having an illuminance of 2 lx is obtained and the half-attenuated exposure amount E is obtained. _{It was set to 1/2} (lx · s). 2 l
The surface potential when the surface of the photoreceptor was irradiated with white light of x for 10 seconds was defined as the residual potential V _r (V). The results are shown in Tables 1 and 2.

[0044]

[Table 1] Example 11 A photoconductor was prepared in the same manner as in Example 1 except that the charge generating substance in Example 1 was replaced with x-type metal-free phthalocyanine.

Example 12 A photoconductor was prepared in the same manner as in Example 3 except that β-type titanyloxyphthalocyanine was used as the charge generating substance in Example 2. Comparative Example 9 1-phenyl-3- (P-diethylaminostyryl) -5- (paradiethylaminophenyl) -2- was used as the charge transport material of Example 10.
A photoconductor was prepared in the same manner as in Example 10 by replacing pyrazoline (ASPP).

Comparative Example 10 A photoconductor was prepared in the same manner as in Example 10, except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Example 10. Comparative Example 11 1-phenyl-3- (P-diethylaminostyryl) -5- (paradiethylaminophenyl) -2- was used as the charge transport material of Example 11.
A photoconductor was prepared in the same manner as in Example 11 except that pyrazoline (ASPP) was used.

Comparative Example 12 A photoconductor was prepared in the same manner as in Example 11 except that P-diethylaminobenzaldehyde-diphenylhydrazone (ABPH) was used as the charge transport material in Example 11. Comparative Example 13 A photoconductor was prepared in the same manner as in Example 10, except that the charge-generating substance in Example 10 was replaced with ε-type copper phthalocyanine.

The electrophotographic characteristics of the photoconductor thus obtained were measured by the electrostatic recording paper testing apparatus "SP-428" manufactured by Kawaguchi Electric Co., Ltd.
It measured using. The surface potential V _S (V) of the photoconductor is −6.0 kV or +6.0 kV corona discharge in the dark.
It is the initial surface potential when the surface of the photoconductor is negatively or positively charged for 2 seconds, and then the surface potential V _D (V) when it is kept in the dark for 2 seconds while the corona discharge is stopped.
Then, the time (s) until V _D becomes half by irradiating the surface of the photoreceptor with monochromatic light having an illuminance of 1 μW and a wavelength of 800 nm is obtained, and a half-attenuated exposure amount E _1/2 (μJ / cm ³ ). The surface potential when the same monochromatic light was applied to the surface of the photoconductor for 10 seconds was defined as the residual potential V _r (V).

[0049]

[Table 2] As shown in Table 1 and Table 2, Examples 1 to 12 are Comparative Examples 1 to 1.
Although the surface potential is equivalent to that of No. 13, the residual potential and the half-attenuation exposure amount are clearly improved, and the distyryl compound as the charge transporting substance represented by the general formula (I) of the present invention and the general formula (I II), the general formula (III), and the general formula (IV), the superiority of combining the compound as the charge generating substance or the phthalocyanine compound as the charge generating substance is clear.

[0050]

INDUSTRIAL APPLICABILITY According to the present invention, the distyryl compound represented by the general formula (I) is used as the charge transporting substance, and the compound represented by the general formulas (II) to (IV) or the specific phthalocyanine is used as the charge generating substance. When used in combination, an electrophotographic photoreceptor for a copying machine or a printer having high sensitivity and excellent repeatability can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a negative charging type electrophotographic photoreceptor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a positive charging type electrophotographic photoconductor according to one embodiment of the present invention.

[Explanation of symbols]

 1 Conductive Substrate 2 Charge Generation Layer 3 Charge Transport Layer 4 Photosensitive Layer 5 Surface Covering Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G03G 5/06 384 G03G 5/06 384 (72) Inventor Masayo Amano Kawasaki-shi, Kanagawa Prefecture Tanabe Shin Arata No. 1-1 No. 1 in Fuji Electric Co., Ltd. (72) Inventor Yoshimasa Hattori Tanabe Nitta No. 1 in Fuji Electric Co., Ltd. (72) Noboru Furusho Shin Tanabe, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 in Fuji Electric Co., Ltd.

Claims (5)

[Claims] 1. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer comprises a distyryl compound represented by the general formula (I) as a charge transporting substance and a bisazo compound represented by the general formula (II) as a charge generating substance. A photoreceptor for electrophotography, which is characterized by including: Embedded image (R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or an alkyl group, and the phenylene group has meta or ortho coordination.) Chemical 2] (R ₇ represents a halogen atom, an alkyl group or an alkoxy group, R ₈ represents a substituted or unsubstituted alkyl group, R 7
₉ represents a hydrogen atom, a cyano group, a carbamoyl group, a carboxy group, an alkoxycarbonyl group or an acyl group, and R
₁₀ represents a hydrogen atom, a halogen atom, a nitro group or a substituted or unsubstituted alkyl group or alkoxy group. ) 2. A photosensitive layer on a conductive substrate, wherein the photosensitive layer is a distyryl compound represented by the general formula (I) as a charge transporting substance and a polycyclic quinone compound represented by the general formula (III) as a charge generating substance. An electrophotographic photosensitive member comprising: Embedded image (R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or an alkyl group, and the phenylene group has meta or ortho coordination.) Chemical 4] (X represents a hydrogen atom, a halogen atom or a cyano group, and n represents an integer of 0 to 4) 3. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer contains a distyryl compound represented by the general formula (I) as a charge transporting substance and a squarylium compound of the general formula (IV) as a charge generating substance. A photoconductor for electrophotography, which is characterized by: Embedded image (R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or an alkyl group, and the phenylene group has meta or ortho coordination.) Chemical 6] (R ₁₁ , R ₁₂ , R ₁₃ , and R ₁₄ are each an optionally substituted alkyl group, aryl group, aralkyl group, or alkenyl group, or R ₁₁ and R ₁₂ or R ₁₃ and R ₁₄ form a ring. R ₁₅ and R ₁₆ each represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group.) 4. A photosensitive layer is provided on a conductive substrate, and the photosensitive layer contains a distyryl compound represented by the general formula (I) as a charge transporting substance and a metal-free phthalocyanine or titanyloxyphthalocyanine as a charge generating substance. Characteristic electrophotographic photoconductor. [Chemical 7] (R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom, a substituted or unsubstituted aryl group or alkyl group, and the phenylene group is in meta or ortho coordination.) 5. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is composed of two layers, a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. A photoconductor for electrophotography, which is characterized by: