JPH032760A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body for a copying machine or a printer having high sensitivity and superior repetitive characteristics by forming a photosensitive layer contg. at least one kind of specified hydrazone compd. CONSTITUTION:A photosensitive layer contg. at least one kind of hydrazone compd. represented by formula I or II is formed. In the formula I, A is an optionally substd. arom. residue, a condensed polycyclic residue or a heterocyclic residue, R1 is optionally substd. aryl and m is 0 or 1. In the formula II, each of R2-R8 is halogen, alkoxy, optionally substd. alkyl, alkenyl, aralkyl or aryl and n is 0 or 1. A sensitive body having high sensitivity at the time of positive charging and negative charging and superior repetitive characteristics is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, it is characterized in that a novel hydrazone compound is contained in a photosensitive layer formed on a conductive substrate. This invention relates to a photoreceptor for electrophotography.

[Conventional technology]

Conventionally, photosensitive materials for electrophotographic photoreceptors (hereinafter also referred to as photoreceptors) have been made using inorganic photoconductive substances such as selenium or selenium alloys, or inorganic photoconductive substances such as zinc oxide or cadmium sulfide in a resin binder. dispersions, organic photoconductive materials such as poly-N-vinylcarbazole or polyvinylanthracene, phthalocyanine compounds or bisazo compounds, or dispersions of these organic photoconductive materials in resin binders. Dispersed ones are used.

In addition, a photoreceptor must have the function of retaining surface charge in the dark, the function of receiving light and generating charge, and the function of receiving light and transporting charge, all of which can be achieved in one layer. A so-called single-layer photoreceptor with the following functions is laminated with functionally separated layers: 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 photoreceptor. For example, the Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation in this method involves charging the photoconductor in a dark place by corona discharge, forming electrostatic latent images such as letters and pictures on the document by exposing the surface of the charged photoconductor, and This is done by developing the latent image with toner, transferring the developed toner image to a support such as paper, and fixing it. After the toner image is transferred, the photoreceptor is charged, the residual toner is removed,
After photostatic charge removal, etc., it is reused.

In recent years, electrophotographic photoreceptors using organic materials have been put into practical use due to their advantages such as flexibility, thermal stability, and film-forming properties. For example, poly-N-vinylcarbazole,! =
2.4.7-) dinitrofluoren-9-one (described in U.S. Pat. No. 3,484,237)
, a photoreceptor whose main component is an organic pigment (Japanese Patent Application Laid-Open No. 47-375
43 (described in Japanese Patent Laid-open No. 43), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (described in Japanese Patent Application Laid-open No. 10785/1983). Furthermore, many new hydrazone compounds have also been put into practical use.

[Problem 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, there is currently no material that fully satisfies all the characteristics required of electrophotographic photoreceptors. In particular, there were problems with photosensitivity and characteristics during repeated and continuous use.

The problem to be solved by this invention is to create a photosensitive layer for copiers and printers that has high sensitivity and excellent repeatability by using a new organic material that has never been used as a charge transport material in the photosensitive layer. An object of the present invention is to provide a photoreceptor for electrophotography.

[Means to solve the problem]

According to the present invention, the above problem is solved by providing a photoreceptor including a photosensitive layer containing at least one of the hydrazone compounds represented by the following general formulas (1) and (II).

[In formula (1), Δ is a substituted or unsubstituted aromatic residue,
represents either a fused polycyclic residue or a heterocyclic residue, R6 represents a substituted or unsubstituted aryl group, m
represents an integer of 0 or 1. ] [Formula (1, R2 to R8 each represent a halogen atom, an alkoxy group, or any of the following substituted or unsubstituted alkyl groups, alkenyl groups, aralkyl groups, and aryl groups,
n represents an integer of 0 or 1. ] [Function] There are no known examples in which the hydrazone compounds represented by the above general formulas (1) and ([1) are used in photosensitive layers.

The present inventors conducted a number of experiments on these hydrazone compounds while intensively studying various organic materials to solve the above-mentioned problems. The above general formula (
We have discovered that the use of specific hydrazone compounds shown in 1) and (II) as charge transport materials is extremely effective in improving electrophotographic properties, and we have found that the use of specific hydrazone compounds shown in 1) and (II) is extremely effective in improving electrophotographic properties, and in order to obtain photoreceptors with high sensitivity and excellent repeatability. It has come to this.

〔Example〕

The hydrazone compound of general formula (1) used in this invention can be synthesized by a conventional method. That is, aldehydes represented by the following general formula (III) and hydrazines represented by the following general formula (IV) are mixed in a suitable organic solvent (such as ethanol) in the presence of a catalyst such as an acid.
It can be easily synthesized by dehydration condensation in a medium.

A(-(H-CHtancho --(IIj) [Formula (
In III), A represents either a substituted or unsubstituted aromatic residue, a fused polycyclic residue or a heterocyclic residue,
m represents an integer of 0 or 1. Moreover, in the formula (rV),
R represents a substituted or unsubstituted aryl group. ] Specific examples of the hydrazone compound represented by the general formula (1) thus obtained are as follows.

Compound N91-7 gl-1O N! ! l-11 N91-12 Compound N91-1 Iza 1-2 gI-4 N=]-5 Compound tooth l-13 N91-14 gI-16 C2H5 Compound N9l-19 Also, the general formula (II) used in this invention ) can be synthesized by a conventional method. That is, by dehydrating and condensing aldehydes represented by the following general formula (V) and hydrazines represented by the following general formula (Vl) in a suitable organic solvent (such as ethanol) in the presence of a catalyst such as an acid, Can be easily synthesized.

[In formulas (V) and (Vl), R2 to Ro each represent a halogen atom, an alkoxy group, or any of the following substituted or unsubstituted alkyl groups, alkenyl groups, aralkyl groups, and aryl groups, and n is 0 or 1
represents an integer. ] Hyza 1 represented by the general formula (II) thus obtained
-24 Compound tooth I! -1 Compound tooth 11-7 Sitting 1l-9 N! ! ll-10? M −6 N911-12 Compound Npl! -13 N911-15 II; The photoreceptor of the invention described in 11-1 contains the above-mentioned hydrazone compound in the photosensitive layer. It can be used as shown in FIG. 2 or 3.

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

FIG. 1 shows a structure in which a charge generating substance 3 and a charge transporting substance 5, hydrazone compounds represented by the general formulas (I) and ([1), are dispersed in a resin binder (binder) on a conductive substrate 1. A photosensitive layer 20 (commonly referred to as a single-layer photosensitive member) is provided.

FIG. 2 shows a charge generation layer 4 mainly composed of a charge generation substance 3 on a conductive substrate 1, and a charge transport substance 5 of the general formula (
A photosensitive layer 21 (commonly referred to as a laminate type photoreceptor) is provided, which is formed by laminating a charge transport layer 6 containing a hydrazone compound represented by 1) or (II). A photoreceptor having this configuration is normally used in a negative charging system.

In FIG. 3, a photosensitive layer 22 having a layer structure opposite to that in FIG. 2 is provided, and is normally used in a positive charging system. In this case, it is common to further provide a coating layer 7 to protect the charge generation layer 4.

The reason why the laminated photoconductor has two types of layer configurations is that even if you try to use a photoconductor with the layer configuration shown in Figure 2, which is normally used for a negative charging system, in a positive charging system, the charge that is compatible with this cannot be used. This is because a transport substance has not yet been found, and therefore, at this stage, it is necessary to use the layer structure shown in FIG. 3 as a positively charging type photoreceptor.

The photoreceptor shown in FIG. 1 can be produced 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 Figure 2 is produced by vacuum-depositing a charge-generating substance on a conductive substrate, or by coating and drying a dispersion obtained by dispersing particles of a charge-generating substance in a solvent or resin binder, and then It can be produced by applying a solution containing a charge transporting substance and a resin binder to the surface of the substrate and drying the solution.

The photoreceptor shown in Figure 3 is made by coating a conductive substrate with a solution containing a charge transport substance and a resin binder.

It is prepared by drying and vacuum-depositing a charge-generating substance thereon, or by applying a dispersion obtained by dispersing charge-generating substance particles in a solvent or resin binder, drying, and further forming a coating layer. can.

The conductive substrate 1 serves as an electrode for the photoreceptor and at the same time serves as a support for the other layers, and may be cylindrical, plate-shaped, or film-shaped, and may be made of aluminum, stainless steel, nickel, etc. It may also be made of metal, glass, resin, or the like, which has been subjected to conductive treatment.

The charge generation layer 4 is formed by applying a material in which particles of the charge generation substance 3 are dispersed in a resin binder as described above, or by a method such as vacuum deposition, and generates charges by receiving light. . In addition, the charge transport layer 6 and the coating layer 7 for the generated charges at the same time have a high charge generation efficiency.
It is important to have good injection properties even in low electric fields with little dependence on electric fields. Examples of the charge generating substance include phthalocyanine compounds such as metal-free phthalocyanine and titanyl phthalocyanine, various azo, quinone, and indigo pigments, or cyanine and squarylium.

Dyes such as azulenium, pyridium compounds,
Selenium or a selenium compound is used, and a suitable substance can be selected depending on the light wavelength range of the exposure light source used for image formation. Since the charge generation layer only needs to have a charge generation function, its film thickness is determined by the light absorption coefficient of the charge generation substance, and is 5 μm or less for boat fishing, preferably 1 μm.
It is as follows. The charge generation layer is mainly composed of a charge generation substance, and a charge transport substance or the like may be added thereto. Polycarbonate is used as a resin binder.

Polyester, polyamide, polyurethane, vinyl chloride, epoxy, diallyl phthalate resin, silicone resin,
It is possible to use a suitable combination of polymers, copolymers, etc. of methacrylic acid esters.

The charge transport layer 6 is a coating film in which a hydrazone compound represented by the general formulas (I) and (n) as an organic charge transport substance is dispersed in a resin binder. It functions to hold and transport charges injected from the charge generation layer when receiving light. As the resin binder, polycarbonate, polyester, polyamide polyurethane, epoxy, silicone resin, polymers and copolymers of methacrylic acid ester, etc. can be used.

The coating layer 7 has the function of receiving and retaining the charge of corona discharge in a dark place, and has the ability to transmit the light to which the charge generation layer is sensitive, and transmits the light upon exposure, and the charge generation layer It is necessary to neutralize and eliminate the surface charges by injecting the generated charges. As the coating material, organic insulating film-forming materials such as polyester and polyamide can be used. In addition, these organic materials and glass resin, 5
It is also possible to use a mixture of inorganic materials such as i02 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 using inorganic materials such as 810□, 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 adverse effects such as an increase in residual potential when used repeatedly and continuously.

Examples of the present invention will be described below.

Example 1 50 parts by weight of metal-free phthalocyanine (manufactured by Tokyo Kasei) milled in a ball mill for 150 hours and the above compound NCL I-1
A coating solution was prepared by kneading 100 parts by weight of a hydrazone compound represented by 100 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) and a tetrahydrofuran (THF) solvent for 3 hours in a mixer. Coated on vapor-deposited polyester film (^1-PET) using wire bar method, film thickness after drying is 15μ
A photoreceptor having the structure shown in FIG. 1 was prepared by forming a photoreceptor layer so as to have a thickness of m.

Example 2 First, α-type metal-free phthalocyanine was used as a starting material, and a non-magnetic separation body containing α-type metal-free phthalocyanine and a coated magnetic Teflon piece as a working piece was used between two linear motors placed opposite each other. The powder was pulverized for 20 minutes using an electromagnetic pulverizer (trade name: LIMMAC, manufactured by Fuji Electric). 1 part by weight of this finely powdered sample and DMF (N,N-dimethylformamide)
Ultrasonic dispersion treatment was performed with 50 parts by weight of a solvent. after that,
The sample and DMF were separated and filtered, dried, and processed for metal-free phthalocyanine.

Next, a coating solution prepared by dissolving 80 parts by weight of the hydrazone compound represented by Compound No. I-2 and 100 parts by weight of polycarbonate resin (trade name Panrai L-1225, manufactured by Ondai) in methylene chloride was applied to aluminum. A charge transport layer was formed by coating on a vapor-deposited polyester film substrate by a wire bar method so that the film thickness after drying was 15 μm. On the charge transport layer thus obtained, 50 parts by weight of the above-treated metal-free phthalocyanine and 50 parts by weight of a polyester resin (trade name: Vylon 200, manufactured by Toyobo Co., Ltd.) were added to TH.
A coating solution prepared by kneading with F solvent in a mixer for 3 hours was applied using a wire bar method, and the film thickness after drying was 1 μm.
A charge generation layer was formed to have a thickness of m, and a photoreceptor corresponding to the structure shown in FIG. 3 was produced. However, a coating layer not directly related to this invention was not provided.

Example 3 In Example 2, a SQUA IJ compound represented by the following structural formula was used instead of the metal-free phthalocyanine,
A photoreceptor was produced in the same manner as in Example 2 except that the charge transport material was replaced with the compound NαI-2 and a hydrazone compound represented by the compound NαI-3 was used.

Example 4 In Example 2, a chlorodiapolymer, which is a bisazo pigment as shown in JP-A-47-37543, was used instead of the metal-free phthalocyanine, and the charge transport substance was changed to the compound NαI-2, and the compound NαI-2 was used. Compound NCLI-4
Using the hydrazone compound shown by, the rest was as in Example 2.
A photoreceptor was produced in the same manner as described above.

Example 5 A photoreceptor was produced in the same manner as in Example 1 except that the charge transport substance was replaced with the compound kll and a hydrazone compound represented by the compound kn-1 was used.

Example 6 In Example 2, a charge transport substance is added to the compound +-2
A photoreceptor was produced in the same manner as in Example 2 except that a hydrazone compound represented by the compound Nαll-2 was used instead of .

Example 7 In Example 3, the charge transport material was the compound kI-3.
A photoreceptor was produced in the same manner as in Example 3 except that a hydrazone compound represented by the compound Nαll-3 was used instead of .

Example 8 In Example 4, the charge transport substance was used as the compound No.
A photoreceptor was produced in the same manner as in Example 4 except that the hydrazone compound represented by the compound NαI[-4 was used instead of -4.

The electrophotographic properties of the photoreceptor thus obtained were measured using an electrostatic recording paper tester RSP-428J manufactured by Kawaguchi Electric.

The surface potential V (volts) of the photoreceptor is +6. Ok
This is the initial surface potential when the surface of the photoreceptor is positively charged by corona discharge of V for 10 seconds, and the surface potential Va is when it is held in the dark for 2 seconds with corona discharge stopped.
<volts), and then apply an illuminance of 2 to the surface of the photoreceptor.
Calculate the time (seconds) it takes for V to be halved after irradiating the white light of Lux. Half-attenuation exposure amount El/2 (lux seconds)
And so. Further, the surface potential when white light with an illuminance of 2 lux was irradiated for 10 seconds was defined as the residual potential V (volt).

In addition, for Examples 1 to 3 and Examples 5 to 7, high sensitivity with long wavelength light can be expected, so the wavelength 78
Electrophotographic properties using 0 nm monochromatic light were also measured at the same time. That is, measurements were taken in the same manner up to Vd, then 1 μW monochromatic light (780 nm) was irradiated instead of white light to obtain the half-attenuation exposure amount (μJ/cd), and this light was applied to the photoreceptor surface for 10 seconds. The residual potential V, (Pol)) was measured when irradiated with . The measurement results are shown in Table 1.

Table 1 As seen in Table 1, Examples 1 to 8 are comparable in both half-attenuation exposure and residual potential, and also exhibit good characteristics in terms of surface potential. In addition, Examples 1 to 3
It can be seen that samples No. 5 to No. 7 show high sensitivity even with long wavelength light of 780 nm, and are sufficiently usable for semiconductor laser printers.

Example 9 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 a solution obtained by dissolving 100 parts by weight of a hydrazone compound represented by Compound N[Li5 in 700 parts by weight of tetrahydrofuran (THF) and polymethyl methacrylate polymer (PMMA:
A coating solution prepared by mixing 100 parts by weight (manufactured by Tokyo Kasei) with a solution prepared by dissolving 700 parts by weight of toluene was applied using a wire bar method to form a charge transport layer so that the film thickness after drying was 20 μm. . The electrophotographic characteristics were measured by corona charging the photoreceptor at -6,0 kV for 10 seconds using the above-mentioned test device rSP-428J.
, V,=-60V, El/2=3.9 lux·sec, and good results were obtained.

Example 10 In Example 9, the charge transport material was the compound NαI-
A photoreceptor was produced in the same manner as in Example 9 except that the hydrazone compound represented by the compound NαI[-5 was used instead of 5.

When the electrophotographic characteristics of the photoreceptor thus obtained were measured in the same manner as in Example 9, Vs=-660V,
Vr=-80V, El/x=4.3root x·sec (!: Good results were obtained.

Example 11 50 parts by weight of the metal-free phthalocyanine treated in Example 2, vinyl chloride copolymer (trade name MR-110: Nippon Zeon Co., Ltd. manufactured by Nippon Zeon) were kneaded with methylene chloride in a mixer for 3 hours to form a coating solution. A charge generation layer was formed by coating the aluminum support to a thickness of approximately 1 μm.Next, Compound N (100 parts by weight of a hydrazone compound represented by LI-6), polycarbonate resin (trade name Panlite L) -1250: manufactured by Kijin), 100 parts by weight of silicone oil and 0.1 part by weight of silicone oil were mixed with methylene chloride and coated on the charge generation layer to a thickness of about 15 μm to form a charge transport layer. A photoreceptor having the configuration shown was produced.

When the electrophotographic characteristics of the photoreceptor thus obtained were measured in the same manner as in Example 9, Vs=-660V
, E l/2 =4.5 lux·sec, and a good result was obtained.

Example 12 In Example 11, the charge transport material was the compound NcL.
A photoreceptor was produced in the same manner as in Example 11 except that a hydrazone compound represented by the compound Nαll-6 was used in place of Nαll-6.

When the electrophotographic characteristics of the photoreceptor thus obtained were measured in the same manner as in Example 11, it was found that: 1=-700V
A good result was obtained with E1/i=4.0 lux·sec.

Example 13 In Example 11, a bisazo pigment represented by the following structural formula was used instead of the metal-free phthalocyanine, and a hydrazone compound represented by the compound Nα was used instead of the charge transport substance Ll-6. A photoreceptor was produced in the same manner as in Example 11 except for the following.

When the electrophotographic characteristics of the photoreceptor thus obtained were measured in the same manner as in Example 11, Vs = 660V.
, E 1y2-4.8 lux·sec, and good results were obtained.

Example 14 In Example 13, the charge transport material was the compound NαI.
A photoreceptor was produced in the same manner as in Example 13 except that a hydrazone compound represented by the compound Nαll-7 was used instead of Nαll-7.

When the electrophotographic characteristics of the photoreceptor thus obtained were measured in the same manner as in Example 11, VS=-680V.
, E l/2 =5.5 lux·sec, and good results were obtained.

Example 15 Photoreceptors were produced in the same manner as in Example 4 for each of the compounds NαI-8 to NαI-24.

These photoreceptors were tested using the aforementioned test equipment "5P428".
" +6. in the dark. Corona discharge at OkV was performed for 10 seconds to positively charge the sample, and the half-attenuation exposure amount E=/2 (lux·sec) when white light with an illuminance of 2 lux was irradiated was measured. The results are shown in Table 2.

As seen in Table 2, the hydrazone compound NαI
The half-attenuation exposure IE1/2 was also good for the photoreceptors using -8 to Nα-24 as charge transport materials.

Example 16 For each of the compounds Nαll-8 to Nαll-16, photoreceptors were prepared in the same manner as in Example 4, and the half-attenuation exposure amount E 172 was measured in the same manner as in Example 15. The results are shown in Table 3.

As seen in Table 3, the hydrazone compound Nαn
The half-attenuation exposure amount E1/ was also good for photoreceptors using -8 to NαIf-16 as charge transport materials.

〔Effect of the invention〕

According to this invention, since the hydrazone compound represented by the general formulas (1) and (II) is used as a charge transport material on a conductive substrate, it is highly sensitive even in positive and negative charging, and has excellent repeatability. An excellent photoreceptor 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 are photosensitive materials that can be used in semiconductor laser printers. You can get a body. moreover,
If necessary, a coating layer can be provided on the surface to improve durability.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are conceptual cross-sectional views showing different embodiments of the photoreceptor of the present invention. 1 conductive substrate, 3 charge generation substance, 4 charge generation layer,
5 charge transport material, 6 charge transport layer, 7 coating layer, 20.
21.22. -・Photosensitive layer.

Claims (1)

[Scope of Claims] 1) An electrophotographic photoreceptor comprising a photosensitive layer containing at least one of the hydrazone compounds represented by the following general formulas (I) and (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [In formula (I), A is any substituted or unsubstituted aromatic residue, fused polycyclic residue, or heterocyclic residue. R_1 represents a substituted or unsubstituted aryl group,
m represents an integer of 0 or 1. [In formula (II), R_2 to R_8 are each a halogen atom, an alkoxy group, or the following substituted or unsubstituted alkyl group, alkenyl represents any one of a group, an aralkyl group, and an aryl group, and n represents an integer of 0 or 1. ]