JPS62275274A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the titled body having sufficient electric chargeability and small residual potential by specifying the compounding ratio of zirconium alkoxide in a cured material of a composition which contains zirconium alkoxide and a silane coupling agent and constitutes an intermediate layer. CONSTITUTION:In the titled body which is formed by laminated an electric charge transfer layer, an electric charge generating layer, an intermediate layer and a surface layer having a low resistance in this order, the intermediate layer is the cured material composed of zirconium alkoxide and the silane coupling agent. The used amount of zirconium alkoxide in said composition is 70-90wt% based on said composition. The effects about repeating stability of the residual potential and the electric potential and surrounding stability are obtained by specifying the compounding ratio of zirconium alkoxide to a specific range. The intermediate layer hinders implantation of the electric charge from a surface of the titled body, and has a role of barrier layer which raises an electrostatic contrast, and also has a function as a adhesive layer between the electric charge generating layer and the surface protective layer having the low resistance.

Description

[Detailed description of the invention] 3. Detailed description of the invention Industrial applications The present invention relates to an electrophotographic photoreceptor.

2. Description of the Related Art In the past, electrophotographic photoreceptors have been proposed in which a photosensitive layer made of various organic or iron-free materials is provided on a support. So-called functionally separated electrophotographic photoreceptors, which have a two-layer structure consisting of a charge generation layer that generates charges upon exposure and a charge transport layer that transports charges, have become mainstream.

In electrophotographic photoreceptors having functionally separated photoreceptors, positively charged type and negatively charged type electrophotographic photoreceptors can be obtained by changing the stacking order of the charge generation layer and the charge transport layer. At present, hole transporting (P-type) charge transporting materials are the mainstream, and there are very few electron transporting materials, and they have not been put to practical use. Therefore, in order to obtain a positively charged laminated, awn-shaped electrophotographic photoreceptor, a charge generation layer is usually laminated on the charge transport layer.

However, since the charge generation layer usually needs to be used in a film thickness of about several microns, it often suffers from the disadvantage that its mechanical strength is weak during repeated use. In order to overcome this drawback, it has been proposed to provide a low-resistance surface protective layer on the top layer, and in order to roughly improve charging properties, charge injection is performed at the interface between the low-resistance surface protective layer and the charge generation layer. It has also been considered 74 to provide a blocking aid layer.

As described above, the reason why the charge injection blocking auxiliary layer is provided at the interface between the low resistance surface protective layer and the charge generation layer is that the existence of the low resistance surface protective layer on the surface causes the charge to flow between the charge generation layer and the charge generation layer. This is because the resistance is not maintained between the resistor surface protective layers and good charging performance cannot be obtained.

A layer made of zirconium alkoxide and a silane coupling agent has been proposed as a material constituting the charge injection blocking auxiliary layer.

Problems to be Solved by the Invention However, even in electrophotographic photoreceptors provided with these layers, residual potential is high even when the charging current is sufficient.
It has the disadvantage that the charging potential 1q and residual potential fluctuate due to changes in temperature and humidity, and that the charging potential and residual potential change during repeated use.

The present invention has been made in view of the above drawbacks.

Therefore, it is an object of the present invention to obtain a sufficient charge i.e.
and to provide an electrophotographic photoreceptor with a small residual potential)
There it is. Another object of the present invention is to provide an electrophotographic photoreceptor whose charging potential and residual light do not change due to changes in temperature and humidity.
The object of the present invention is to provide an electrophotographic photoreceptor whose charging potential and residual potential are stable even after repeated use.

Means for Solving the Problems As a result of intensive studies, the inventors of the present invention have developed an electronic structure in which a charge transport layer, a charge generation layer, an intermediate layer, and a low resistance surface layer are sequentially laminated on a conductive support. In a photographic photoreceptor, the above-mentioned drawbacks can be improved by adjusting the proportion of zirconium alkoxide within a specific range in a cured product of a composition comprising a zirconium alkoxylate and a silane coupling agent forming an intermediate layer. They discovered this and completed the present invention.

In other words, the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which a charge transport layer, a charge generation layer, an intermediate layer, and a low resistance surface layer are sequentially laminated on a conductive support. is a cured product of a composition comprising zirconium alkoxide and a silane coupling agent, and is characterized in that the proportion of zirconium alkoxide in the composition is 70 to 90% by weight.

Each layer constituting the inventive electrophotographic photoreceptor will be explained below.

The conductive support in the electrophotographic photoreceptor of the present invention includes a full-length drum or sheet made of aluminum, copper, iron, zinc, nickel, etc., and aluminum, copper, gold, silver, platinum on paper, plastic, or glass. , palladium, titanium, nickel-chromium, stainless steel, 1. Either by evaporating the same indium, by evaporating a conductive metal compound (e.g. InO5n02), or by laminating a metal foil. , or carbon black, conductive metal compounds (e.g., In2O3, 5b203-8nOSnO
2. Tl0X) 1. A drum-like, sheet-like or plate-like material is used, which has been treated to be conductive by dispersing metal powder into a binder resin and coating it.

The charge transport layer in the electrophotographic photoreceptor of the present invention contains a charge transport material, and the charge transport materials include pyrene, j\-ethylcarbasol, -isopropylcarbasol, 2 .b-bis(p-diethylaminophenyl)-1,3,4-oxadiazole, 1-phenyl-3-(p-diethylaminostyryl)-5-(p-
diethylaminophenyl)pyrazoline, 1-[pyridyl-(2)I'-3-(p-diethylaminostyryl)-
5-(p-diethylaminophenyl)pyrazoline, 1-
"Kinotrue (2>3-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, triphenylamine, N, N'-diphenyl-
N, N=-bis(3-methylphenyl)-[1,1”-
biphenyl]-4,4-diamine, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone,
4.4--henzylidenehis(N,N--diethyl-
m-toluidine, poly-N-vinylcarbazole, loginated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, poly-9-vinylphenylanthracene, polyester-formaldehyde resin, ethylcarbazole-formaldehyde resin, etc. It will be done. These charge transport materials can be used alone or in a mixture of two or more. Charge transport materials are not limited to those described herein.

Binder resins used in the charge transport layer include general-purpose resins such as acrylic resin, methacrylic resin, polystyrene, polyester, polyacrylate, Bossal 7one, and polycarbonate, and hole-transporting resins such as poly-N-vinylcarbazole. Polymers can be used. Note that a contact layer may be provided between the conductive support and the charge transport layer.

The charge generation layer in the electrophotographic photoreceptor of the present invention contains a charge generation material, and examples of the charge generation material include amorphous selenium, trigonal selenium, zinc oxide, titanium oxide, selenite alloy, AS2Se3, Metals - metal-free phthalocyanine, squareium pigment, anthracene, pyrene, perylene, pyrylium salt, cyanine, chiapyri
Noum salt, polyvinylcarbazole, etc. can be used.

Binder resins in the charge generation layer include polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, and polyacrylamide. , polyvinylbutyral, polyester, polyvinylpyridine, polyvinyl alcohol, polyvinylcarbazole, thermoplastic resins such as casein, thermosetting resins such as polyurethane, epoxy resins, and phenolic resins. used.

Next, the middle layer, which is a feature of the present invention, will be explained.
This intermediate layer is made of a cured product of a composition containing zirconium alkoxide and a cyan coupling agent. This intermediate layer serves as a barrier layer that prevents charge injection from the surface of the electrophotographic photoreceptor and increases electrostatic contrast, and also serves as an adhesive between the charge generation layer and the low-resistance surface protection film. It is possible to have the following powers. In the present invention, it is necessary that the cured product forming the intermediate layer be formed using a composition consisting of zirconium, alkoxide, and a silane coupling agent in a proportion of 70 to 90% by weight of zirconium alkoxide. is. Only when the proportion of zirconium alkoxide is within the above range will effects be achieved in terms of residual potential, repeated stability of charged potential, and environmental stability.

In the present invention, the zirconium alkoxide is
For example, zirconium alkoxides such as zirconium tetra-n-butoxide and zirconium tetra-n-propoxide can be used.

Examples of silane coupling agents suitable for the intermediate layer include the following. Vinyltrichlorosilane, vinyltriethoxysilane, vinyltris-β-methoxyethoxy-silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-aminoethyl-γ-7 minobrovir Trimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminoallopyltriethoxysilane, methyltrimethoxysilane, dimethyl Dimethoxysilane, trimedelmonomethoxysilane, diphenyldimethoxysilane, diphenyljethoxysilane, monophenyltrimethoxysilane.

In the present invention, among these zirconium alkoxide and silane coupling agents, zirconium tetra n-butoxide Zr-(QC4t19)4 having the structural formula (1) is used as the zirconium alkoxide.
It is preferred to use γ-methacryloxypropyltrimethoxysilane of structural formula (II>) as (I) and as a silane coupling agent.

In the present invention, this intermediate layer is formed by spray coating,
It can be carried out by any suitable method such as dip coating, knife coating, or roll coating.

In the electrophotographic photoreceptor of the present invention, the low-resistance surface layer is a layer in which fine particles of a conductive metal oxide are dispersed in an insulating resin, and the electrical resistance of the conductive metal oxide is 109Ω.
Fine particles with an average particle size of 0.3 µm or less, preferably 0.1 µm or less and exhibiting white, gray or blue-white color at a size of 0.3 µm or less, such as antimony oxide, tin fermentation, titanium oxide, indium oxide, etc., are suitable. Examples include a solid solution of tin and antimony or antimony oxide, or a mixture thereof, or a single particle kneaded with these metal oxides, or coated with a metal oxide.

Among these, tin oxide and antimony, a solid solution of antimony oxide, or tin oxide are preferably used because they can lower the electrical resistance and make the protective layer substantially transparent (Japanese Patent Laid-Open No. 57 -30847, JP-A-57-128344).

The electrical resistance of the low resistance surface layer is 109 to 1014Ω・c
It is desirable to configure it so that m. electrical resistance is 10
If it exceeds 14 Ω·cm, the residual potential will increase, resulting in copies with a lot of fog, and if it falls below 10 9 Ω·cm, the image will become blurred and the resolution will decrease. In addition, the low resistance surface layer must be constructed so as not to substantially impede passage of the φ light used for @ exposure. If the particle size of the conductive metal oxide used is too large, the low resistance surface layer becomes opaque, resulting in desensitization and a decrease in image density. The particle size is determined by the wavelength of the light used for image exposure (0.42 to 0.8 μm
), it is desirable to use particles having a particle size of one-half or less, that is, 0.3 μm, preferably 0.1 μm or less. Further, as the insulation 1 resin, it is desirable to use an electrically insulating transparent resin whose electrical resistance does not easily change due to changes in humidity or temperature. Examples of the main insulation resin include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, and polyacrylamide. It is preferably used in terms of physical stability. Conductivity [It is desirable that the fine particles of the main metal oxide are dispersed in the insulating resin from 20ffiff1% to 60% by weight. Below 20% by weight,
The electrical resistance was more than 1014 Ω・cm, and the resistance was 60
If it exceeds 1%, the film strength of the low-resistance surface layer will drop significantly. Therefore, preferably from 30% by weight to 501% by weight.
The dispersion is done in the range of ffi%.

The thickness of each layer in the electrophotographic photoreceptor of the present invention is suitably 5 μTrL to 40 μ71'L, preferably 8 μTrL to 30 μm for the charge transport layer, and 5 μm or less, preferably 0.1 μm to 3 μm for the charge generation layer. , for the intermediate layer, 5 μm or less, preferably 1 μm or less, and for the low resistance surface layer, 0.5 μTrL to 20 A1 m, preferably 1 μTn, to 10 μm.

Example Hereinafter, the present invention will be explained by examples.

Example 1 On an aluminum substrate, a charge transport layer, a charge generation layer, an intermediate layer, and a low resistance surface layer having the following compositions were sequentially laminated by spray coating to produce five types of electrophotographic photoreceptors.

Charge transport layer (thickness: 20 μm) Polycarbonate resin 50 layers (extra: Panlite) N, N'-diphenyl-N, N'-bis 5
0-fold moiety (3-methyl)-[1,1°-biphenyl]-4,4°-diamine charge generation layer (film thickness 1 μTrL) 35 parts by weight squaric acid derivative represented by the following structural formula (III) - Polyester resin 65 Hasebe (Toyobo: Byron 200) Intermediate layer (thickness: 0.1 μTrL) Represented by the above structural formula (I>) See the table below for zirconium butoxide (Matsumoto Pharmaceutical: ZA)
-60) Represented by the above structural formula (I [>) See the table below for silane coupling agents (Shin-Etsu Chemical: K
B) f 503) Low resistance surface layer (thickness: 2 μm) Tin oxide powder: 40 parts Polyurethane resin: 60 parts Analyzer 5P-42
8>, perform a corona discharge at +5 to obtain a positive voltage, measure the surface potential V DDP after discharging in a dark place for 1 hour, and immediately after that, irradiate with 5 lux tungsten light for 3 seconds. , the light lE1/2 required to reduce V DDP by half was determined. After this, the surface potential was roughly attenuated by irradiation with 200 lux light for 0.5 seconds, and the residual potential RP was determined.

This measurement was performed 1000 times in succession, and the 1st cycle and 1st cycle were
Difference between V DOP and RP at 000th cycle, ΔDDP
(C) and ARP (C) were measured to determine cycle stability [
I gave the raw review a 1.

Similar measurements were also carried out under an environment of 10°Cl2O%RH and at 30°C.
'C Performed in an environment of 180% RH, difference in y:i boundary fluctuations of vDDP and RP, △VDDP (E) and ARP (E)
was measured to evaluate environmental stability.

The measurement results are shown in FIGS. 1 to 4.

As is clear from FIGS. 1 to 4, the proportion of zirconium butoxide in the components forming the intermediate layer is 70 to 9.
In the range of 0% by weight, the electrophotographic photoreceptor exhibits sufficient charging, low residual potential, good cycle stability and environmental stability, and has excellent overall electrophotographic properties. It turns out that it has

Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that a square 1 monoacid derivative represented by the following structural formula (IV) was used in place of the squaric acid derivative in Example 1. When measurements were carried out in the same manner as in Example 1, the same trends as in Example 1 appeared depending on the proportion of zirconium butoxide.

Example 3 A charge transport layer, a charge generation layer, an intermediate layer, and a low-resistance surface layer having the following compositions were sequentially laminated on an aluminum substrate,
Five types of electrophotographic photoreceptors were produced.

Charge transport layer (thickness 20 μm) Polycarbonate resin 604 parts (extra: Panlite) N,N'-diethylaminobenz 40 parts by weight Aldehyde-1,1-diphenylhydrazone charge generation layer (thickness 1 μTrL) Structural formula (V) below Represented by 5QT4U 1 part squaric acid π Shudo 1 V Polyvinyl butyral 50% but (tan water chemistry: BM-1> Intermediate 13 (I! Film thickness, 1 μm) In the above structure j blue formula (I) 70 parts by weight of zirconium but-1-oxide (Matsumoto Yakuhin: 2A-60) 30 parts by weight of a silane coupling agent (Shin-Etsu Chemical: KPM 503) represented by the above structural formula (II) Surface protective layer (thickness: 2 μm) ) Tin oxide: 0 parts 4 parts by weight Polyurethane resin 60 parts by weight The electrophotographic properties of the obtained electrophotographic photoreceptor were measured and evaluated in the same manner as in Example 1, and the following results were obtained. Ta.

VDDP: 1100V Hi 1/2: 1.2 lux・sec RP: 60V ΔVl)DP (C>: 140 VARP(C)
:20 ΔVDDP(E) : 130 VARP(E)
:30V From the above results, it can be seen that the electrophotographic photoreceptor of Example 3 has sufficient chargeability, high sensitivity, and excellent cycle stability and environmental stability.

Example 4 An electrophotographic photoreceptor was produced in the same manner as in Example 3, except that the surface protective layer in Example 3 was changed to tin oxide-opened antimony solid solution/polyurekne stringer = 40/60 (parts by weight). Measurements were made in the same manner.

The measurement results are as follows, and it was found that the electrophotographic photoreceptor of Example 3 exhibited stable characteristics.

VDDP: 1050V El/2: 1.2 Lux・sec RP Near 0V ΔVDDP (C): 130 VARP (C)
:30V ΔVDDP (E): 120 VARP(lx)
:20 Example 5 On an aluminum substrate, a charge transport layer, a charge generation layer, an intermediate layer, and a low resistance surface layer having the following composition were sequentially laminated,
Five types of electrophotographic photoreceptors were produced.

Charge transport layer (thickness 20 μm) Polycarbonate resin 60 parts by weight (large amount: Panlite) N,N'-diethylaminobenz 40 parts by weight Aldehyde-1,1-diphenylhylazone charge generation layer (thickness 1 μm) 'rrL) Represented by the following structural formula (VI) 50 parts by weight Squaric acid derivative polyvinyl butyral 50 parts by weight (tank water chemistry: BM-1> Intermediate layer (thickness 0.1 μm) In the above structural formula (1) 70 parts by weight of zirconium butoxide (Matsumoto Pharmaceutical: ZA-60) 3 parts by weight of silane coupling agent (Shin-Etsu Chemical: BM 503) Surface protective layer (thickness: 2 μm) Tin oxide powder: 40 parts by weight Polyurethane resin: 60 parts by weight The electrophotographic properties of the obtained electrophotographic photoreceptor were measured in the same manner as in Example 1 and evaluated as 1iT+, and the following results were obtained.

VDDP: 10()Ov El/2: 1.3 Lux・sec RP: 80V 8VD[)P (C): 150 VARP(C)
: 50V ΔvDDP (E) : 120V ARP (F) : 30V Example 6 Except that the surface protective layer formed in Example 5 was changed to tin oxide-antimony oxide solid solution/polyurethane resin = 40/60 (overlapping part). An electrophotographic photoreceptor was prepared in the same manner as in Example 5, and measured in the same manner.

The measurement results are as follows, and it was found that the electrophotographic photoreceptor of Example 5 exhibited stable characteristics.

VDDP: 100OV E1/2: 1.2 Lux・sec RP Near 0V ΔVDDP (C): 120V ARP(C): 20V ΔvDDP (E): 110V ARP(E): 20V Effects of the Invention Electrophotography of the present invention The photoreceptor not only has a low residual potential with no decrease in charging potential, but its charging potential and residual potential are not easily affected by changes in temperature or humidity or by repeated use. The electrophotographic photosensitive material of the present invention has high photosensitivity, excellent environmental stability, and excellent cycle stability.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the surface potential and residual potential of samples No. 1'1 to \0°5 of Example 1, and FIG. 2 is a graph showing the surface potential and residual potential of samples No. 1 to 1N0.5 of Example 1. Graph showing the half-decreased exposure amount of lIF Nicle, Figure 3 (ko 1, also samples No. 1 to 1, the 1st cycle of 5 and 10001
A graph showing the difference between the surface potential and residual potential of Nikle eyes,
FIG. 4 is a graph showing variations in surface potential and residual potential of samples \0°1 to No. 5 due to environmental changes. 1 2345 °V DDP Sample No., ° RPl 2
3 Otsu 5 Sample No. Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor in which a charge transport layer, a charge generation layer, an intermediate layer, and a low resistance surface layer are sequentially laminated on a conductive support, the intermediate layer is made of zirconium alkoxide and a silane coupling agent. A cured product of a composition in which the proportion of zirconium alkoxide in the composition is 7.
An electrophotographic photoreceptor characterized in that the content is 0 to 90% by weight. (2) The electrophotographic photoreceptor according to claim 1, wherein the zirconium alkoxide is zirconium butoxide, and the silane coupling agent is γ-methacryloxypropyltrimethoxysilane.