JPH04128765A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve an electrostatic charge characteristic, dark attenuation characteristic, sensitivity, and response characteristic by incorporating a specific amine compd. and hydrazone compd. into a charge transfer layer. CONSTITUTION:This photosensitive body is constituted of a conductive base body 11, a charge generating layer 12 and the charge transfer layer 13. The amine compd. expressed by formula I and the hydrazone compd. expressed by formula II are incorporated into the charge transfer layer 13. In the formula I, R1 to R4 respectively denote any of an alkyl group, aralkyl group, aryl group, heteroplycyclic group, tenyl group which may be respectively substd.; X denotes aryl, etc.; Y denotes the group expressed by formula III, etc.; R5, R6 denote an alkyl group. In the formula II, Ar denotes any of an aryl group, condensed polycyclic group and heterocyclic group which may be respectively substd.; R1, R2 respectively denote an alkyl group and any of an aralkyl group, aryl group, heteropolycyclic group and tenyl group which may be respectively substd. The electrostatic charge characteristic, dark attenuation characteristic, sensitivity, and response characteristic are improved in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor for copying machines and printers, which is equipped with a charge transport layer and a charge generation layer containing an organic material. Related to photographic photoreceptors.

[Conventional technology]

In recent years, research on organic photoconductive substances has been widely advanced as photosensitive materials for electrophotographic photoreceptors (hereinafter simply referred to as photoreceptors) used in laser beam printers and copying machines. Photosensitive materials using organic photoconductive substances have greater flexibility, thermal stability, film-forming properties, and
Although it has many advantages such as transparency and price, it has disadvantages such as poor dark resistance and light sensitivity. Taking advantage of the ease of film formation, the photosensitive layer of the photoreceptor is functionally separated into a layer that primarily contributes to charge generation and a layer that contributes to retaining surface charge in the dark and transporting charge during light reception. By selecting materials suitable for the functions of each layer, we aim to improve the electrophotographic properties as a whole, and are moving forward with practical application.

This type of laminated photoreceptor usually has a structure in which a charge generation layer containing an organic charge generation substance and a charge transport layer containing an organic charge transport substance are formed on a conductive substrate. The charge generating layer is made of a charge generating material such as a phthalonanine compound having an absorption peak in the infrared light region for laser beam printers, and an azo compound having an absorption peak in the visible light region for copying machines. It is formed by applying a coating liquid containing a binding agent such as polyester, acrylic, etc., dispersed in a resin binder. On the other hand, the charge transport layer is formed by applying a coating liquid in which a low molecular weight compound such as hydrazone or pyrazoline is used as a charge transport substance and mixed with a binder resin binder such as polycarbonate.

When forming an image using such a laminated structure organic photoreceptor, the Carlson method is generally applied. Specifically, the photoreceptor is charged by corona discharge in a dark place, the surface of the charged photoreceptor is exposed to light to form an electrostatic latent image such as text or pictures on a document, and the formed electrostatic latent image is Development with toner,
Image formation is performed by transferring and fixing the developed toner image onto a support such as paper, and after the toner image has been transferred, the photoreceptor is charged.

After residual toner is removed and static electricity is removed, it is reused.

[Problem to be solved by the invention]

Such a laminated structure organic photoreceptor has a charge generating section and a charge transporting section separated in function, so that each can be designed optimally, which is advantageous in terms of characteristics, and is currently the mainstream.

As mentioned above, the laminated structure organic photoreceptor has many advantages.

However, it does not simultaneously satisfy all of the electrophotographic properties required for a photoreceptor, such as charging characteristics, dark decay characteristics, light decay characteristics, repetition characteristics, photo fatigue characteristics, three spectral characteristics, and response characteristics. Depending on the charge transport material,
Some have good dark decay characteristics but poor response characteristics, and others have good response characteristics but poor dark decay characteristics. Attempts have been made to improve the photofatigue characteristics by mixing various charge transport materials with these materials, but by mixing them, new traps are formed, and the mobility of the charge transport materials in the mixed material is that of the individual components. It is known that the mobility is lower than that of

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a photoreceptor with good electrophotographic properties without deterioration of properties by mixing a specific charge transporting substance. The task is to

[Means to solve the problem]

According to the present invention, the above-mentioned problem is solved by a photoreceptor comprising a charge generation layer and a charge transport layer made of an organic material on a conductive substrate, in which the charge transport layer contains an amine compound represented by the following general formula (A). The problem can be solved by preparing a photoreceptor containing a hydrazone compound represented by the following general formula (B) as a charge transport material.

In formula (A), R, , R2, R, and R1 each represent any one of the following optionally substituted alkyl groups, aralkyl groups, aryl groups, heteropolycyclic groups, and thenyl groups.

X represents an aryl group or -()←y-@→, and q represents an alkyl group. [In formula (B), Ar represents any one of the following optionally substituted aryl groups, fused polycyclic groups, and heterocyclic groups. R, and R2 each represent any one of an aralkyl group, an aryl group, a heteropolycyclic group, and a thenyl group, each of which may be substituted with an alkyl group. ] The problem can also be solved by preparing a photoreceptor in which the charge transport layer contains an amine compound represented by the following general formula (C) and a hydrazone compound represented by the following general formula (D) as a charge transport material. Ru.

6 formula (in CJ, R,, R,, R,, R,, Rs, R, are each a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, a heteropolycyclic group, a thenyl group) ] In formula 6 (D), R, , R, and R each represent a hydrogen atom.

Represents a halogen atom, or any of the following optionally substituted alkyl groups, aralkyl groups, aryl groups, heterocyclic groups, and thenyl groups. RIG represents any one of a hydrogen atom, a halogen atom, and an alkyl group. ] As the above-mentioned hydrazone compound, a compound represented by the following formula (E) is particularly suitable.

The charge-transporting layer of the charge-generating layer on the conductive substrate may be formed by laminating the charge-transporting layer on the charge-generating layer, or vice versa.

Specific examples of the compound represented by the general formula (A) include the following.

(, H5) Specific examples of the compound represented by the general formula (B) include the following.

Further, specific examples of the compound represented by the general formula (C) include the following.

Further, specific examples of the compound represented by the general formula (D) include the following.

[Effect]

By using a mixture of the amine compound represented by the general formula (A) and the hydrazone compound represented by the general formula (B) as the charge transport material, photoreceptor characteristics having the advantages of each can be obtained. That is, when used individually as a charge transport material, an amine compound represented by the general formula (A) with good photoreceptor response characteristics and a hydrazone compound represented by the general formula (B) with good dark decay characteristics are mixed. By using the photoreceptor as a material, a photoreceptor with good response characteristics and dark decay characteristics can be obtained.

Amine compound represented by general formula (C) and general formula (D)
A photoreceptor having excellent characteristics can be obtained by using a mixture of the above and a hydrazone compound as a charge transport material.

Furthermore, it is particularly preferable to use a compound represented by the above formula (E) as the above-mentioned hydrazone compound.

The effect of using the above-mentioned mixture as a charge transport material does not change depending on the order in which the charge generation layer and the charge transport layer are stacked, and is equally effective for photoreceptors of any configuration.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are cross-sectional views showing different embodiments of the photoreceptor of the present invention, showing a negatively charged multilayer organic photoreceptor and a positively charged multilayer organic photoreceptor, respectively.

In the negatively charged multilayer organic photoreceptor shown in FIG. 1, a charge generation layer 12. The charge transport layer 13 is sequentially formed.

The conductive substrate 11 serves as an electrode for the photoreceptor and at the same time serves as a support for other layers, and is made of metal such as aluminum, glass, resin, etc., which has been subjected to conductive treatment. But it's okay. The charge generation layer 12 is made of a phthalonanine compound having an absorption peak in the infrared light region in a photoreceptor for a laser beam printer, and an azo compound having an absorption peak in the visible light region in a photoreceptor for a copying machine. It is formed by applying a coating liquid containing a generated substance dispersed in a binding resin binder such as polyester or acrylic.

On the other hand, the charge transport layer 13 is formed by applying a coating liquid in which a low molecular weight compound such as amine or hydrazone is used as a charge transport substance and mixed with a binder resin binder such as polycarbonate or polycarbonate Z.

In the positively charged multilayer organic photoreceptor shown in FIG. 2, a charge transport layer 23 and a charge generation layer 22 are sequentially formed on a conductive substrate 21, and a coating layer 24 is formed thereon for the purpose of protecting the charge generation layer. . The covering layer 24 uses an organic insulating material such as polyester or polyamide. The conductive substrate, charge transport layer, and charge generation layer are the same as those used in the negatively charged organic photoreceptor.

Hereinafter, specific examples of the present invention will be described.

Example 1 The following formula (F
60 parts by weight of the bisazo compound shown in ) and vinyl chloride resin 4
A charge generation layer is formed using a coating liquid in which 0 parts by weight of 0 parts by weight are dispersed in a methyl ethyl ketone solvent. On top of that, 50 parts by weight of a 2:8 mixture of the diamine compound (A-4) and the hydrazone compound (B-4) as a charge transport material, 50 parts by weight of polycarbonate, and 40 parts by weight of dichloromethane.
A charge transport layer was formed using a coating liquid dissolved in 0 parts by weight so as to have a thickness of 20 μm after drying, thereby preparing a laminated photoreceptor.

Example 2 Diamine compound (8-4) and (B
A laminated photoreceptor was produced in the same manner as in Example 1 except that a 5:5 mixture of the hydrazone compounds in i) was used.

Example 3 Diamine compound (A-4) and (B
A laminated photoreceptor was produced in the same manner as in Example 1 except that a mixture of the hydrazone compound of -4) and 228 was used.

Comparative Example 1 A laminated photoreceptor was produced in the same manner as in Example 1 except that the diamine compound (A-4) was used alone as the charge transport material.

Comparative Example 2 A laminated photoreceptor was produced in the same manner as in Example 1 except that the hydrazone compound (B-''4) was used alone as the charge transport material.

Table 1 shows the results of measuring the characteristics of the photoreceptors of Examples 1 to 3 and Comparative Examples 1 and 2. The photoreceptor surface was charged to -600V by corona discharge using an electrostatic recording paper tester RSP-428° manufactured by Kawaguchi Electric, and then
The charge retention rate in the dark after 2 seconds was defined as V, 5 (%). Further, the sample was charged to -600V and irradiated with white light at an illuminance of 2 lux to determine the time required for the surface potential to reach 1300V, which was defined as half-attenuation exposure IE, 2 (lux seconds).

As seen in Table 1, Comparative Example 1 is inferior in v, 5, and Comparative Example 2 is inferior in E 172. Compared to these, Examples have better vks and El/2, and the effect of mixing the diamine compound (A-4) and the hydrazone compound (B-4) to form a charge transport material is clear.

Example 4 A charge generation layer is formed on an aluminum substrate using a coating liquid in which 50 parts by weight of X-type phthalonanine as a charge generation substance and 50 parts by weight of a polyester resin are dispersed in dichloromethane. On top of that, diamine compound (A-3) and hydrazone compound (B-7) were added as a charge transport substance at a ratio of 5:5.
50 parts by weight of a mixture of
A charge transport layer was formed using a coating liquid in which 0 parts by weight of 0 parts by weight of dichloromethane was dissolved in 400 parts by weight of dichloromethane so as to have a thickness of 20 μm after drying, thereby preparing a laminated photoreceptor.

Comparative Example 3 A laminated photoreceptor was produced in the same manner as in Example 4 except that the diamine compound (A-3) was used alone as the charge transport material.

Comparative Example 4 A multilayer photoreceptor was produced in the same manner as in Example 4 except that the hydrazone compound (B-7) was used alone as the charge transport material.

Example 5 The following formula (G
A charge generation layer is formed using a coating liquid in which 50 parts by weight of the SQUA IJ compound shown in ) and 50 parts by weight of vinyl chloride resin are dispersed in an ethyl acetate solvent. In addition, as a charge transport substance, (A-2> diamine compound and (B-14)
The charge transport layer was dried with a coating solution prepared by dissolving 50 parts by weight of a mixture of hydrazone compound of A laminated photoreceptor was formed.

Comparative Example 5 A laminated photoreceptor was produced in the same manner as in Example 5 except that the diamine compound (A-2) was used alone as the charge transport material.

Comparative Example 6 A laminated photoreceptor was produced in the same manner as in Example 5 except that the hydrazone compound (B-14) was used alone as the charge transport material.

Table 2 shows the results of measuring the characteristics of the photoreceptors of Examples 4 and 5 and Comparative Examples 3 to 6. The surface of the photoreceptor thus obtained was charged to -6C1OV by corona discharge using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric.
The charge retention rate in the dark after 5 seconds was defined as Vks (%). In addition, it is charged to -600V and monochromatic light (wavelength 78
0nm), and calculate the time until the surface potential reaches -300V, and calculate the half-attenuation exposure amount E, 2 (μJ/cm').
And so.

As seen in Table 2, it is clear that Example 4 has better photoreceptor characteristics than Comparative Example 3.4, and Example 5 has better photoreceptor characteristics than Comparative Example 5.6. be.

Example 6 The above formula (F
) Bisazo compound 60 weight! A charge generation layer is formed using a coating liquid in which 1 ffl and 40 parts by weight of vinyl chloride resin are dispersed in a methyl ethyl ketone solvent. On top of that, a diamine compound (C-1) and (D-1) are added as a charge transport substance.
The charge transport layer was dried with a coating solution prepared by dissolving 50 parts by weight of an 8:2 mixture of Noto and Dracin compounds and 50 parts by weight of polycarbonate in 400 parts by weight of dichloromethane, so that the film thickness would be 20 μm after drying. A laminated photoreceptor was formed.

Example 7 Diamine compound (C-1) and (D
A laminated photoreceptor was produced in the same manner as in Example 6 except that a 5:5 mixture of the hydrazone compounds of -1) was used.

Example 8 Diamine compound (C-1) and (D
A laminated photoreceptor was produced in the same manner as in Example 6 except that a mixture of the hydrazone compounds of -1) in a ratio of 2=8 was used.

Comparative Example 7 A laminated photoreceptor was produced in the same manner as in Example 6 except that the diamine compound (C-1) was used alone as the charge transport material.

Comparative Example 8 A laminated photoreceptor was produced in the same manner as in Example 6 except that the hydrazone compound (D-1) was used alone as the charge transport material.

Example 9 Diamine compound (C-2) and (D
A laminated photoreceptor was produced in the same manner as in Example 6 except that a 5:5 mixture of the hydrazone compounds of -1) was used.

Example 10 Diamine compound (C-3) and (D
A laminated photoreceptor was produced in the same manner as in Example 6 except that a mixture of 5.5 and 5.5% of the hydrazone compound of -1) was used.

Example 11 Charge transporting substance, diamine compound (C-4) and (D
A laminated photoreceptor was produced in the same manner as in Example 6 except that a 5:5 mixture of the hydrazone compounds of -1) was used.

Example 12 Diamine compound ((, -5) and (
A laminated photoreceptor was produced in the same manner as in Example 6 except that a 5:5 mixture of the hydrazone compounds of D-1) was used.

These Examples 6-8, Comparative Example 7.8 and Examples 9-1
The characteristics of the photoreceptor No. 2 were measured in the same manner as in Examples 1-3.

The measurement results are shown in Table 3.

/ / / / / / / / / From Table 3, it is clear that the Examples have better photoreceptor characteristics than the Comparative Examples.

Example 13 A charge generation layer is formed on an aluminum substrate using a coating liquid in which 50 parts by weight of X-type phthalocyanine and 50 parts by weight of polyester resin are dispersed in dichloromethane as a charge generation substance. On top of that, a diamine compound (C-1>) and a hydrazone compound (D-2) were added as a charge transport substance.
A charge transport layer was formed using a coating solution prepared by dissolving 50 parts by weight of a mixture of 5 and 50 parts by weight of polycarbonate in 400 parts by weight of dichloromethane so that the film thickness after drying would be 20 μm. As a body.

Comparative Example 9 A laminated photoreceptor was produced in the same manner as in Example 13 except that the diamine compound (C-1) was used alone as the charge transport material.

Comparative Example 10 A multilayer photoreceptor was produced in the same manner as in Example 13 except that the hydrazone compound (D-2) was used alone as the charge transport material.

Example 14 The above formula (G
) A charge generation layer is formed using a coating liquid in which 50 parts by weight of the squarylium compound shown in (a) and 50 parts by weight of a vinyl chloride resin are dispersed in an ethyl acetate solvent. On top of that, 50 parts by weight of a mixture of the diamine compound (C, 1) and the hydrazone compound (D-6) in a ratio of 5=5 as a charge transport substance;
50 parts by weight of polycarbonate and 40 parts by weight of dichloromethane
A charge transport layer was formed using a coating liquid dissolved in 0 parts by weight so that the film thickness after drying would be 20 μm to obtain a laminated photoreceptor.

Comparative Example 11 A laminated photoreceptor was produced in the same manner as in Example 14 except that the diamine compound (C-1) was used alone as the charge transport material.

Comparative Example 12 A multilayer photoreceptor was produced in the same manner as in Example 14 except that the hydrazone compound (D-6) was used alone as the charge transport material.

The characteristics of the photoreceptors of Examples 13 and 14 and Comparative Examples 4 to 12 were measured in the same manner as in Example 4.5.

The measurement results are shown in Table 4.

From Table 4, it is clear that Examples 13 and 14 have better photoreceptor characteristics than Comparative Examples 9.10 and 11.12, respectively.

Although the above embodiments are photoreceptors in which a charge transport layer is laminated on a charge generation layer, the present invention is not limited to this structure, and the present invention is equally effective in photoreceptors with the opposite layer structure. .

〔Effect of the invention〕

According to the present invention, in the layered organic photoreceptor, the charge transport layer contains a mixture of the amine compound represented by the general formula (A>) and the hydrazone compound represented by the general formula (B) as a charge transport substance; By using a mixture of the amine compound represented by the formula (C) and the hydrazone compound represented by the general formula (D), the response characteristics are good and the sensitivity is high.
In addition, a photoreceptor with good dark decay characteristics and excellent charge retention can be obtained.

As the above-mentioned hydrazone compound, a compound represented by the above formula (E) is particularly suitable.

Furthermore, the effect of using the above-mentioned mixture as a charge transport material does not change depending on the stacking order of the charge generation layer and the charge transport layer. Therefore, by stacking the charge transport layer on the charge generation layer, negative charging can be achieved. A photoreceptor with an excellent type can be obtained, and by having the opposite structure, a photoreceptor with an excellent positive charge type can be obtained.

Further, the charge generating material used in the charge generating layer can be selected from a suitable material depending on the type of exposure light source, such as a phthalocyanine compound.

By using a squarylium compound or the like, a photoreceptor that can be applied to a semiconductor laser beam printer can be obtained.

Furthermore, if necessary, it is possible to provide a coating layer on the surface to improve durability.

[Brief explanation of drawings]

FIGS. 1 and 2 are structural sectional views showing different embodiments of the photoreceptor of the present invention.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer made of an organic material on a conductive substrate, wherein the charge transport layer is an amine represented by the following general formula (A). An electrophotographic photoreceptor comprising a compound and a hydrazone compound represented by the following general formula (B). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(A) [In formula (A), R_1, R_2, R_3, and R_4 are each of the following optionally substituted alkyl groups, aralkyl groups, aryl groups, and hetero Represents either a polycyclic group or a thenyl group. X represents an aryl group or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, Y represents ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R_5 and R_6 are alkyl groups represents. ] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(B) [In formula (B), Ar is any of the following optionally substituted aryl groups, fused polycyclic groups, and heterocyclic groups. represents. R_1 and R_2 each represent an alkyl group, or any one of the following optionally substituted aralkyl groups, aryl groups, heteropolycyclic groups, and thenyl groups. 2) In an electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer made of an organic material on a conductive substrate, the charge transport layer comprises an amine compound represented by the following general formula (C) and an amine compound represented by the following general formula (C). An electrophotographic photoreceptor comprising a hydrazone compound represented by (D). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(C) [In formula (C), R_1, R_2, R_3, R_4, R_
5 and R_6 each represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, a heteropolycyclic group, or a thenyl group. ] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(D) [In formula (D), R_7, R_8, and R_9 are hydrogen atoms, halogen atoms, and the following optionally substituted alkyl groups and aralkyl groups, respectively. , represents any one of an aryl group, a heterocyclic group, and a thenyl group. R_1_0 represents any one of a hydrogen atom, a halogen atom, and an alkyl group. 3) An electrophotographic photoreceptor according to claim 1 or 2, characterized in that the hydrazone compound used in the charge transport layer is a hydrazone compound represented by the following formula (E). Photoreceptor for use. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(E) 4) In the electrophotographic photoreceptor described in claim 1, 2, or 3, a charge generation layer is provided on a conductive substrate. , a charge transport layer are laminated in this order. 5) An electrophotographic photoreceptor according to claim 1, 2, or 3, characterized in that a charge transport layer and a charge generation layer are laminated in this order on a conductive substrate. Photographic photoreceptor.