JPH05313385A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body excellent in dark decay characteristics and senstivity by forming a laminated structure of charge generation layer and charge transfer layer and using a specified hydrazone compds. and amine compd. as a charge transfer material in the charge transfer layer. CONSTITUTION:This photosensitive body has a charge generating layer and a charge transfer layer on a conductive substrate. The charge generating layer contains a charge generating material, while the charge transfer layer contains a hydrazone compd. expressed by formula I and an amine compd. expressed by formula II. In the formula I, R1-R3 are hydrogen atoms, halogen atoms, or alkyl groups, aralkyl groups, aryl groups, heterocyclic groups or thenyl groups which may be substd., R4 is a hydrogen atom, halogen atom, or alkyl group, and in the formula II R5-R7 are hydrogen atoms, halogen atoms, or alkyl groups, aralkyl groups, aryl groups, heterocyclic groups or thenyl groups. The mixing ratio of the hydrazone compd. expressed by the formula I to the amine compd. expressed by the formula II used as a charge transfer material is made at (9:1) to (2:8).

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,
In particular, it relates to substances used for the charge transport layer of 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, 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 which vacuum-deposited are used.

Organic photoconductive materials have advantages such as flexibility, thermal stability, film forming property, transparency, and cost as compared with inorganic photoconductive materials, but are inferior in terms of dark resistance, photosensitivity, and the like. ing.
Therefore, by taking advantage of the film-forming property, the photosensitive layer is made into a laminated layer in which the layer mainly contributing to the charge generation and the layer contributing to the surface charge in the dark place and the layer contributing to the charge transport at the time of light reception are separated and suitable for the function of each layer. We are working to improve electrophotographic characteristics by selecting different materials and put them into practical use.

This type of laminated type photoreceptor has a structure in which a charge generating layer containing an organic charge generating substance and a charge transporting layer containing an organic charge transporting substance are formed. The charge generation layer uses a phthalocyanine compound having an absorption peak in the infrared light region for a laser beam printer and an azo compound having an absorption peak in the visible light region as a charge generation substance for a copying machine. It is formed by coating with the coating liquid dispersed in the binder substance binder.

For example, the Carlson method is applied to the image formation by the electrophotographic method using these photoconductors. Image formation by this method is performed 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, and electrostatic latent image formed. Of the developed toner image and the developed toner image is fixed on a support such as paper.After the toner image has been transferred, the photoconductor is discharged, residual toner is removed, and light is discharged. To be done.

[0006]

The laminated organic photoreceptor has many advantages as described above, but the characteristics required for the photoreceptor are charging characteristics, dark decay characteristics, light decay characteristics, repetitive characteristics, and light fatigue. At present, there is no material that satisfies all the characteristics such as characteristics, spectral characteristics, response characteristics, etc., and depending on the charge transport material, dark decay characteristics are good, but sensitivity is poor. In addition, although the characteristics when used alone were good, there were some cases in which the ratio to the binder could not be increased because the solubility was low.

Although attempts have been made to improve the response characteristics by mixing a charge-transporting substance in order to improve the above-mentioned points, a new trap is generated by mixing and the mobility during mixing is the mobility of each component. Could be lower than. The present invention has been made in view of the above points, and an object thereof is to provide an electrophotographic photosensitive member which is excellent in both dark decay characteristics and sensitivity by combining a novel charge transport material.

[0008]

According to the present invention, the above-mentioned object has a charge generating layer and a charge transporting layer on a conductive substrate, the charge generating layer containing a charge generating substance, and the charge transporting layer is generally The hydrazone compound represented by the formula (A) and the general formula (B)
It is achieved by including an amine compound represented by

[0009]

[Chemical 2]

(R ₁ , R ₂ and R ₃ are hydrogen atoms,
Halogen atom or optionally substituted alkyl group, aralkyl group, aryl group, heterocyclic group, tenyl group, R ₄ is hydrogen atom, halogen atom, alkyl group, R ₅ , R ₆ , R ₇
Represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, a heterocyclic group, and a tenyl group, respectively. )
Specific examples of the general formula (A) are shown in the chemical formulas (A-1) to (A-6).

A specific example of the general formula (B) is a chemical formula (B-1).
To the chemical formula (B-8).

[0012]

[Chemical 3]

[0013]

[Chemical 4]

[0014]

The hydrazone compound of the general formula (A) has good sensitivity characteristics. Further, the compound of the general formula (B) has good dark decay characteristics. By combining both of them, an electrophotographic photoreceptor having good dark attenuation characteristics and sensitivity characteristics can be obtained. In addition, the mixture is substantially diluted so that a coating solution can be prepared and a charge transport layer can be formed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a negatively charged electrophotographic photoreceptor according to an embodiment of the present invention. FIG. 2 is a sectional view showing a positively charged electrophotographic photosensitive member according to another embodiment of the present invention.

In the negative charging laminated type photoreceptor, the charge generation layer 12 and the charge transport layer 13 are sequentially laminated on the conductive substrate 11. 1
Reference numeral 4 denotes a photosensitive layer, which is a function separation type in which a charge generation layer and a charge transport layer are separated. The conductive substrate 11 serves as an electrode of the photoconductor and at the same time serves as a support for each of the other layers, and may be cylindrical, plate-shaped, or film-shaped, and is made of aluminum, stainless steel, nickel, or the like. A metal, glass, resin, or the like that has been subjected to a conductive treatment may be used.

The charge generation layer 12 uses a phthalocyanine compound having an absorption peak in the infrared region for a laser beam printer and an azo compound having an absorption peak in the visible region for a copying machine as a charge generating substance. polyester,
It is formed by coating with a coating liquid dispersed in a binder resin binder such as acrylic. On the other hand, the charge transport layer 13 contains a hydrazone compound represented by the general formula (A) and an amine compound represented by the general formula (B) in polycarbonate or polycarbonate Z.
It is formed by coating with a coating liquid mixed with a binder such as.

In the positive charging laminated type photoreceptor, the charge transport layer 13, the charge generating layer 12 and the surface coating layer 15 are formed on the conductive substrate 11.
Are sequentially laminated. The surface coating layer 15 uses an organic insulating material such as polyester or polyamide. The conductive substrate, the charge transport layer, and the charge generation layer are the same as those of the negative charging type. The surface coating layer 15 has excellent durability against mechanical stress and is made of a chemically stable substance, has a function of receiving and retaining the electric charge of corona discharge in a dark place, and the electric charge generating 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 of the maximum light absorption of the charge generating substance.

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 coat agent is used. Silicone 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 thickness of the coating layer itself depends on the composition of the coating layer, but can be arbitrarily set within a range such that the residual potential does not increase when repeatedly used continuously. Example 1 A chemical formula (C) was used as a charge generating substance on an aluminum substrate.
A charge generation layer was formed by using a coating liquid prepared by dispersing 60 parts by weight of the bisazo compound shown in 1 and 40 parts by weight of vinyl chloride resin in a methyl ethyl ketone solution. Next, the chemical formula (A-
A coating liquid in which 50 parts by weight of a mixture of the hydrazone compound shown in 3) and the amine compound represented by the chemical formula (B-1) in a ratio of 8: 2 and 50 parts by weight of a polycarbonate resin are dissolved in 400 parts by weight of dichloromethane. Was used to form a charge-transporting layer so that the film thickness after drying was 20 μm to obtain a laminated-type photoreceptor.

[0021]

[Chemical 5]

Example 2 As a charge transport substance, 5: 5 of the hydrazone compound represented by the chemical formula (A-3) and the amine compound represented by the chemical formula (B-1) were used.
A laminated type photoreceptor was obtained in the same manner as in Example 1 except that the mixture was used in the ratio of. Example 3 As a charge transport material, 2 to 8 of the hydrazone compound represented by the chemical formula (A-3) and the amine compound represented by the chemical formula (B-1) were used.
A laminated type photoreceptor was obtained in the same manner as in Example 1 except that the mixture was used in the ratio of. Comparative Example 1 A multilayer type photoreceptor was obtained in the same manner as in Example 1 except that the hydrazone compound represented by the chemical formula (A-3) was used as the charge transport material. Comparative Example 2 A laminated type photoreceptor was obtained in the same manner as in Example 1 except that the amine compound represented by the chemical formula (B-1) was used as the charge transport material. Example 4 In the same manner as in Example 1 except that the charge transporting material used was a mixture of the hydrazone compound represented by the chemical formula (A-1) and the amine compound represented by the chemical formula (B-1) at a ratio of 8: 2. A laminated photoreceptor was obtained. Example 5 In the same manner as in Example 1 except that a mixture of the hydrazone compound represented by the chemical formula (A-4) and the amine compound represented by the chemical formula (B-1) in a ratio of 8: 2 was used as the charge transport material. A laminated photoreceptor was obtained. Example 6 In the same manner as in Example 1 except that a mixture of the hydrazone compound represented by the chemical formula (A-3) and the amine compound represented by the chemical formula (B-6) in a ratio of 8: 2 was used as the charge transport material. A laminated photoreceptor was obtained. Example 7 In the same manner as in Example 1 except that a mixture of the hydrazone compound represented by the chemical formula (A-1) and the amine compound represented by the chemical formula (B-6) at a ratio of 8: 2 was used as the charge transport material. A laminated photoreceptor was obtained.

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.
Was measured. The surface of the photoreceptor is -6 by corona discharge.
After charging to 00V, the charge retention rate in the dark after 5 seconds was set to Vk5 (%). Further, by charging to −600 V and irradiating white light with an illuminance of 2 lx, the time until the surface potential becomes −300 V is obtained, and the half-attenuation exposure amount E _1/2 (lx ·
s). The results are shown in Table 1.

[0024]

[Table 1] Example 8 A charge generating layer was formed on an aluminum substrate by using a coating liquid in which 50 parts by weight of X-type phthalocyanine and 50 parts by weight of a polyester resin were dispersed in dichloromethane as a charge generating substance. Next, 50 parts by weight of a mixture of the hydrazone compound represented by the chemical formula (A-3) and the amine compound represented by the chemical formula (B-1) in a ratio of 5: 5, and 50 parts by weight of the polycarbonate resin are 400 parts by weight of dichloromethane. The coating liquid dissolved in was used to form a charge transport layer so that the film thickness after drying was 20 μm, to obtain a laminated type photoreceptor. Comparative Example 3 A laminated type photoreceptor was obtained in the same manner as in Example 8 except that the hydrazone compound represented by the chemical formula (A-3) was used as the charge transport material. Comparative Example 4 A laminated type photoreceptor was obtained in the same manner as in Example 8 except that the amine compound represented by the chemical formula (B-1) was used as the charge transport material. Example 9 A chemical formula (D) was used as a charge generating substance on an aluminum substrate.
A charge generation layer was formed using a coating liquid prepared by dispersing 50 parts by weight of the squarylium compound shown in 1 and 50 parts by weight of a vinyl chloride resin in ethyl acetate. Next, 50 parts by weight of a mixture of the hydrazone compound represented by the chemical formula (A-3) and the amine compound represented by the chemical formula (B-1) in a ratio of 5: 5, and 50 parts by weight of a polycarbonate resin are mixed with 40 parts of dichloromethane.
Using a coating solution dissolved in 0 part by weight, the film thickness after drying is 20
A charge-transporting layer was formed so as to have a thickness of μm to obtain a laminated type photoreceptor.

[0025]

[Chemical 6] Comparative Example 5 A laminated type photoreceptor was obtained in the same manner as in Example 9 except that the hydrazone compound represented by the chemical formula (A-3) was used as the charge transport material. Comparative Example 6 A laminated type photoreceptor was obtained in the same manner as in Example 9 except that the amine compound represented by the chemical formula (B-1) was used as the charge transport material. The obtained photoconductor is used as an electrostatic recording tester “S
P-428 ”, and the surface of the photoconductor by corona discharge
After charging to 600 V, the charge retention rate in the dark after 5 seconds was set to Vk5 (%). Further, the time until the surface potential becomes −300 V is obtained by irradiating a monochromatic light (wavelength: 780 nm) charged at −600 V with an illuminance of 1 μW, and the half-attenuation exposure amount E is obtained.
_{It was set to 1/2} (μJ / cm ² ). The results are shown in Table 2.

[0026]

[Table 2]

[0027]

According to the present invention, a charge generating layer and a charge transporting layer are provided on a conductive substrate, the charge generating layer contains a charge generating substance, and the charge transporting layer is represented by the general formula (A). Since the compound and the amine compound represented by the general formula (B) are contained as the charge transporting substance, the advantages of the two charge transporting substances are combined, and an electrophotographic photoreceptor having excellent dark decay characteristics and sensitivity can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a negatively charged electrophotographic photosensitive member according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a positively charged electrophotographic photosensitive member according to another embodiment of the present invention.

[Explanation of symbols]

 11 Conductive Substrate 12 Charge Generation Layer 13 Charge Transport Layer 14 Photosensitive Layer 15 Surface Coating Layer

Claims (3)

[Claims] 1. A charge generating layer and a charge transporting layer are provided on a conductive substrate, the charge generating layer contains a charge generating substance, and the charge transporting layer comprises a hydrazone compound represented by the general formula (A) and a general formula (A). An electrophotographic photosensitive member comprising the amine compound represented by B) as a charge-transporting substance. [Chemical 1] (R ₁ , R ₂ and R ₃ are each a hydrogen atom, a halogen atom or an optionally substituted alkyl group, an aralkyl group, an aryl group, a heterocyclic group, a tenyl group, R ₄ is a hydrogen atom, a halogen atom, an alkyl group, R ₅ , R ₆ and R ₇ represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, a heterocyclic group and a tenyl group, respectively.) 2. The electrophotographic photoreceptor according to claim 1, wherein the charge transporting material represented by the general formula (A) and the charge transporting material represented by the general formula (B) are mixed in a mixing ratio of 9: 1 and 2.
A photoconductor for electrophotography, which is in a range of 8 pairs. 3. The electrophotographic photosensitive member according to claim 1, wherein the charge transporting substance represented by the general formula (A) has R _{1 and} R ₂ as a methyl group, R _{3 and} R ₄ as a hydrogen atom, and The charge-transporting substance represented by B) is a photoreceptor for electrophotography, wherein R _5, R ₆ are hydrogen atoms, and R ₇ is a methyl group.