JPH0996917A - Electrophotographic photoreceptor and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoreceptor having good printing characteristics even after repeatedly used and having excellent reliability without deteriorating quality under high temp. and high humidity conditions by forming an undercoat layer in such a manner that the layer has density gradient of halogens which increases from the face in contact with a conductive base body to a face in contact with a photosensitive layer. SOLUTION: A coating liquid for the base layer is prepared by mixing a forming material of the base layer and an org. solvent. By making a density profile of halogens in the base layer, the obtd. photoreceptor has excellent electric characteristics, printing quality and durability. To give the density profile of halogens, two or more kinds of coating liquids having different halogen contents are prepared. A liquid having a lower density is used to form a first base layer and then a liquid having a higher density is used to form a second layer. After the base layer is formed, the film is dried and hardened. Proper temp. and time are decided according to the glass transition temp. and the like of the resin used in this process, thereby controlling the density of halogens to a specified density profile in the layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated organic photoconductor used in electrophotographic devices such as copying machines, printers, plain paper FAX, etc., among which carbon, hydrogen, nitrogen, oxygen, chlorine, iodine, fluorine, etc. The present invention relates to an organic photoreceptor having a halogen-containing layer and a method for producing the same, which has a low residual potential, high sensitivity, and does not cause printing defects such as black spots, white spots, memory on printing, and deterioration of resolution. The present invention relates to a photoconductor that does not cause deterioration in quality due to storage at high temperature and high humidity or low temperature and low humidity, has excellent long-term printing durability, and particularly does not cause printing defects due to repeated use, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, as described in JP-B-55-42380 and JP-B-60-34099, a laminated organic photosensitive material in which a charge generation layer and a charge transport layer are laminated on a conductive substrate. The body is being developed. These laminated organic photoconductors include, for example, a charge-generating substance coated with a resin binder of a certain kind, a dispersion liquid together with an organic solvent, and dried to form a charge-generating layer and a charge-transporting substance both as a resin binder and as an additive. The charge transport layer is formed by applying and drying a solution dissolved in a solvent.

In such a photoreceptor, printing defects such as black spots are generated in an electrophotographic process using reversal development,
Problems such as a decrease in print density due to an increase in residual potential occur. Therefore, a technique is known in which a resin layer called an undercoat layer or an intermediate layer is provided between the conductive substrate and the charge generation layer. For example, alcohol-soluble polyamide resins (Japanese Patent Publication No. 58-45707, Japanese Patent Publication No. 60-168157) are known. As a method of forming the undercoat layer, it is known to apply the coating and drying steps as described above.

FIG. 1 is a sectional view showing an electrophotographic photosensitive member. The charge generation layer and the charge transport layer are laminated type photosensitive layers.
There is also a single layer type photosensitive layer. As the conductive substrate, various metals and alloys, conductive resins, etc. are used, but it is general to use a lightweight aluminum cylinder having good workability and a resin containing carbon (conductive resin).

[0005]

However, although the photoconductors produced by these methods can initially obtain good print quality and electrical characteristics, they are repeatedly used (for example, A4 size).
The size of 10,000 prints causes accumulation of electric charges remaining in the photosensitive layer, resulting in defects such as generation of black spots and increase in residual potential. Further, when an aluminum alloy is used as the conductive substrate, there are problems that the film is deteriorated by the reaction between halogen and aluminum under high temperature and high humidity, gas is generated, and the substrate and the undercoat layer are separated.

Further, the heat treatment after coating the undercoat layer is generally a curing treatment at a constant temperature. In such a case, problems such as residual solvent, precipitation due to a difference in compatibility between the additive material and the organic resin, etc. Was occurring. As a result of intensive studies on the organic photoreceptor having a halogen-containing undercoat layer, the present inventors have found that appropriately designing the halogen concentration distribution state is extremely effective in solving the above problems. The present invention has been completed based on this finding.

The present invention has been made in view of the above points, and an object thereof is to optimize the halogen concentration distribution in the undercoat layer so that the printing characteristics are good even after repeated use, and the printing characteristics under high temperature and high humidity are high. An object of the present invention is to provide an electrophotographic photosensitive member which is free from quality deterioration and excellent in reliability and a method for manufacturing the same.

[0008]

According to the first aspect of the present invention, the above object is to provide a halogen-containing subbing layer on a conductive substrate,
In an electrophotographic photosensitive member formed by sequentially stacking photosensitive layers,
This is achieved by setting the concentration of halogen in the undercoat layer to have a concentration gradient that increases from the surface in contact with the conductive substrate to the surface in contact with the photosensitive layer.

According to the second invention, in the first invention, the undercoat layer comprises a first undercoat layer having a relatively low halogen concentration and a second undercoat layer having a relatively high halogen concentration. It is effective to have two layers laminated. According to a third aspect of the present invention, in a method for producing an electrophotographic photoreceptor comprising a halogen-containing undercoat layer and a photosensitive layer, which are sequentially laminated on a conductive substrate, a coating for the undercoat layer containing an organic resin and halogen. This can be achieved by applying the liquid onto a conductive substrate, performing a dry heat treatment, and then performing a heat treatment for curing the organic resin.

According to the fourth aspect of the present invention, in the method for producing an electrophotographic photoreceptor comprising a conductive substrate, a halogen-containing undercoat layer and a photosensitive layer, which are sequentially laminated, in the organic resin, the organic resin contains halogen. And the step of immersing the obtained undercoat layer in a halogen-containing solution. According to the fifth invention, the first undercoating layer having a relatively low halogen concentration and the second undercoating layer having a relatively high halogen concentration in the second invention contain a reactive gas containing different concentrations of halogen. Is achieved by the plasma polymerization method.

According to the sixth invention, it is achieved by forming the first and second undercoat layers in the second invention by using alloys containing different concentrations of halogen.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the conductive substrate is a known aluminum alloy such as JIS 3003 series, JI.
S5000 series, JIS6000 series, etc. can be applied. These conductive substrates are finished to a predetermined dimensional accuracy by extruding, drawing and cutting aluminum.

If necessary, the surface of the conductive substrate is finished to have an appropriate surface roughness by cutting with a diamond cutting tool or the like. After that, the cutting oil used for processing is removed and cleaned, and an aluminum oxide layer is formed by treatment such as anodic oxidation, acid etching, and alkali etching. A conductive resin can also be used as the conductive substrate in the present invention. In particular, it is preferable to use a cross-linked type polyphenylene sulfide resin as a main component, and to add highly conductive carbon black thereto.

After that, pre-coating cleaning is performed. Conventionally, a chlorine-based organic solvent such as CFC was used, but in recent years, a water-based cleaning agent such as a weak alkaline detergent is used for the purpose of protecting the ozone layer. . Next, an undercoat layer is applied, but in order to improve the adhesion with the conductive substrate, the surface of the conductive substrate may be modified by a method such as ultraviolet irradiation, ozone exposure, or chemical etching.

As the undercoat layer, a resin having excellent adhesion to the surface of the conductive substrate after being washed with a water-based detergent or after being modified and excellent in coating property is selected, but appropriate charge injection property and blocking property are selected. A resin containing halogen is selected to provide the. That is, a halogenated resin such as vinyl chloride, soluble fluorinated ethylene, brominated phenoxy, iodine-containing melamine, and the like, which contains chlorine, fluorine, bromine, iodine, etc. added as ions, complexes, and molecules, is used.

The thickness of the undercoat layer using these materials is preferably 0.5 μm or more. When the surface roughness of the substrate and the particle shape of the additive remain during the formation of the photosensitive layer, an image defect may occur due to coating unevenness of the photosensitive layer. Therefore, when forming the undercoat layer, It is preferable that the layer has a certain thickness or more, for example, 0.5 μm or more.
When a photoreceptor having a photosensitive layer including this undercoat layer is used in a laser beam printer, interference patterns are likely to occur depending on the combination of the refractive index of the photosensitive layer, its thickness, the wavelength of the light source, and the like. To prevent this, a method of processing the conductive substrate of the photoconductor to have a specific surface roughness, addition of an absorbing material that absorbs light of the wavelength of the light source to the undercoat layer, and fine particles that induce light scattering are used. A method such as addition to the pulling layer is required.

A coating liquid for the undercoat layer is prepared by mixing these undercoat layer forming materials (the above-mentioned resin, interference preventing agent, curing agent, conductivity-imparting agent, etc.) and an organic solvent.
An undercoat layer having an appropriate film thickness is formed using this coating liquid, and as the method, a dipping method, a spray method and the like are known. The main object of the present invention is to provide a photoreceptor having excellent electric characteristics, printing quality and durability by providing a halogen concentration profile in the undercoat layer. As a specific method for providing the halogen concentration profile, two or more kinds of coating liquids having different halogen contents are prepared, a low concentration liquid is used for the first undercoat layer, and a high concentration liquid is used for the first concentration. Method of applying 2 undercoat layers in this order, and method of generating a predetermined concentration distribution by using halogen diffusion during heat treatment after coating 1 undercoat layer with one type of coating liquid Is mentioned.

After coating the undercoat layer, the film is dried and cured. Appropriate temperature and time are determined depending on the glass transition temperature of the resin used in this step, the curing temperature when a curing agent is used, the boiling point of the organic solvent, and the like. Further, it has been made clear in the present invention that halogen in the layer can be set to a predetermined concentration profile by appropriately setting drying and curing conditions. It is most effective to have a temperature profile in the drying oven and curing oven, but in some cases 2
It is also possible to set the concentration profile by a multi-step process of two steps or more depending on different temperatures and times.

As other methods, a plasma polymerization method of a source gas containing halogen in the molecule, a vacuum deposition method of a halogen-containing alloy, etc. can be applied. After that, the undercoat layer surface is modified for the same reason as the modification treatment on the conductive substrate. Ultraviolet irradiation is applied as the surface modification step of the undercoat layer. 184.9 with common UV lamps
nm and 253.7 nm cleave the molecular bonds on the surface of the undercoat layer, activating the surface. Further, the same effect can be obtained by the chemical treatment as described above. In the present invention, this step is not particularly limited.

In the photoreceptor according to the present invention, the charge generation layer is formed on the undercoat layer. The charge generating substance is not particularly limited as long as it is a material having a photosensitivity to a wavelength of a laser light source such as metal-free phthalocyanine and various metal phthalocyanines, and a material having a spectral sensitivity suitable for white light such as an azo pigment. The charge transport layer according to the present invention is formed on the charge generation layer, and contains one or more charge transport substances such as polyvinylcarbazole, oxadiazole, imidazole, pyrazoline, hydrazone, and stilbene. Accordingly, those containing an antioxidant, an ultraviolet absorber, etc. are used. Example 1 An aluminum alloy having the following composition was used to obtain a conductive substrate having a diameter of 30 mm and a length of 250 mm (Table 1).

[0021]

[Table 1] Further, the surface of the substrate was diamond-finished to have a maximum surface roughness of 0.5 micron.

An aqueous detergent (Lion Co., Ltd. MF)
-10) Immerse in a 5% solution at a temperature of 50 ° C. for 3 minutes, perform ultrasonic cleaning, and then brush-clean with the same detergent,
The surface was cleaned by the steps of rinsing with purified water (addition of ultrasonic waves for 3 minutes), rinsing with pure water (3 minutes with addition of ultrasonic waves), rinsing with ultrapure water, and drying with warm pure water (temperature 70 ° C). Subsequently, an undercoat layer having the following composition was formed by dip coating to have a thickness of 5 μm.

Melamine resin (Mitsui Toatsu Chemicals: Uban 21R) 50 parts by weight Trimellitic anhydride (Wako Pure Chemicals Reagent) 7 parts by weight Iodine (Wako Pure Chemicals Reagent) 8 parts by weight Hydrophobic silica (Japan Aerosil) 35 parts by weight Methyl alcohol 700 parts by weight This is followed by drying at 100 ° C for 20 minutes, and then 140 ° C.
After 20 minutes of heat curing, the drum was dipped in a solution having the following composition for 10 minutes to add iodine to the surface.

Iodine (Wako Pure Chemicals Reagent) 3 parts by weight Methyl alcohol 100 parts by weight The iodine concentration on the surface of the undercoat layer thus obtained was 55% by weight. On the other hand, the iodine concentration on the side of the conductive substrate is 8% by weight, which is the same as the concentration with respect to the non-volatile content in the coating liquid, thus forming a pseudo two-layer structure.

Further, an ultraviolet irradiation device (Sun Engineering Co., Ltd .; SUV200NS) was used to improve the adhesion for 20 seconds at a lamp-photosensitive member distance of 20 mm and a lamp voltage of 200V. The charge generation layer was dip coated with a coating solution having the following composition to a thickness of 0.1 micron. X-type metal-free phthalocyanine 1 part by weight Polyvinyl butyral 1 part by weight Tetrahydrofuran 98 parts by weight The charge transport layer was dip-coated with a coating solution having the following composition to a thickness of 20 μm.

6 parts by weight of hydrazone compound (south fragrance: CTC191) 4 parts by weight of butadiene compound (south fragrance: T-405) 10 parts by weight of polycarbonate resin (Teijin: C-1400) 80 parts by weight of dichloromethane As described above When a printing test was carried out by mounting the produced photoconductor on a laser beam printer, the initial print density was 1.42 (by a Macbeth densitometer), a blank paper density was 0.0.
5 (according to a Macbeth densitometer), and the number of black spots having a diameter of 0.1 mm or more was 4, which was good per one revolution of the drum. As a result of Gobangme test (JIS K5400), peeling was 0/1.
00 was good.

Further, according to the printing test after the running test of 100,000 sheets was conducted with this drum, the printing density was 1.4.
1, the white paper density was 0.06, the number of black dots was 5 and the differences from the initial stage were not found, and film peeling during the test did not occur. Furthermore, this photoconductor is placed in an environment of 60 ° C and 90% relative humidity for 1
After leaving for 500 hours, a printing test, a Gobangme test, and a running test were performed, and the same good results as before the leaving were obtained.

The iodine concentration in the undercoat layer of this drum was measured by an ion microanalyzer IMA, and was found to be about 8% on the conductive substrate side, and from the position of about 0.4 μm from the charge generation layer on the charge generation layer side. The iodine concentration increased rapidly. Comparative Example 1 A photoconductor was prepared under the same conditions as in Example 1 except that the addition treatment with the iodine solution was omitted.

The iodine concentration in the undercoat layer of this drum is approximately uniform from the side of the conductive substrate to the side of the charge generation layer, and is about 8
%Met. However, there was a decrease in concentration on the outermost surface, which was about 6%. In addition, according to the printing test after the running test of 100,000 sheets was performed on this drum, the printing density was decreased.
An increase in white paper density, that is, background fog was observed. It was clarified that the phenomenon was caused by the decrease of the charging position and the increase of the bright part potential due to the increase of the residual potential from the measurement result of the electric characteristics.
That is, a photosensitive member in which the iodine concentration is not high on the charge generation layer side has a large characteristic variation due to repeated use. Example 2 A photoconductor was prepared in the same manner as in Example 1 except that the conductive substrate was replaced with polyphenylene sulfide (PPS) resin (containing carbon black) having a volume resistance of 100 Ω · cm.

A printing test was carried out by mounting the photoconductor thus prepared in a laser beam printer. Initially, the printing density was 1.41 (by Macbeth densitometer) and the white paper density was 0.06 (Macbeth density). The total number of black dots having a diameter of 0.1 mm or more was as good as two per one round of the drum. In addition, Gobangme test (JIS K540
As a result of 0), the peeling was as good as 0/100.

Further, according to a printing test after a running test of 100,000 sheets was carried out with this drum, the printing density was 1.
40, white paper density of 0.06, and number of black dots of 3 were not found, and film peeling during the test did not occur. In addition, place this photoreceptor in an environment of 60 ° C and relative humidity of 90%.
After leaving for 500 hours, a printing test, a Gobangme test, and a running test were performed, and good results were obtained in the same manner as before leaving.

The iodine concentration distribution at this time was the same as in Example 1. Example 3 A photoconductor was prepared in which the undercoat layer had the following two-layer structure. First layer: Melamine resin (Mitsui Toatsu Chemicals; Uban 20SB) 50 parts by weight Ammonium benzoate (Wako Pure Chemicals Reagent) 7 parts by weight Iodine (Wako Pure Chemicals Reagent) 8 parts by weight Fine particle titanium oxide (Ishihara Sangyo) 35 parts by weight Part Methyl alcohol 700 parts by weight Drying condition 100 ° C., 20 minutes Curing condition 135 ° C., 20 minutes Film thickness 9 μm Second layer: Melamine resin (Mitsui Toatsu Chemicals; Uban 20SB) 20 parts by weight Ammonium benzoate (Wako Pure Chemical Reagent) ) 7 parts by weight Iodine (Wako Pure Chemicals Reagent) 63 parts by weight Particulate titanium oxide (Ishihara Sangyo) 10 parts by weight Methyl alcohol 700 parts by weight Drying conditions 100 ° C, 20 minutes Curing conditions 140 ° C, 20 minutes Film thickness 1 μm Also for this photoreceptor Similar to Example 1, it showed good characteristics. Example 4 In the same manner as in Example 3, a photoconductor was prepared in which only the halogen content of the second undercoat layer was changed, and the halogen concentration dependence was evaluated. The results are shown in Table 2.

[0033]

[Table 2] The meanings of the symbols indicating the evaluation results at this time are as follows.

◯: Good printing is shown even after running 100,000 sheets. Δ: Printing is deteriorated by running 100,000 sheets.
There is no problem in practical use. X: Printing with problems in practical use due to running 100,000 sheets. It can be seen that good printing durability is exhibited when the iodine concentration in the second undercoat layer is higher than the iodine concentration in the first undercoat layer. . Example 5 A sample was prepared and evaluated under the same conditions as in Example 3 except that the first and second undercoat layers were prepared under the following conditions.

Sample A: Plasma Polymerization Method First Undercoat Layer Raw Material Gas C ₂ H ₂ (50%) and CF ₄ (50%) Gas Pressure 13.3 Pa Discharge Power 500 W Fluorine 10% Second Undercoat Layer Raw Material Gas C ₂ H ₂ (30%) and CF ₄ (70%) Gas pressure 13.3 Pa Discharge power 500 W Fluorine 18% Sample B: Vacuum evaporation method First undercoat layer Raw material alloy 500 ppm Chlorine-containing SeAs Vacuum degree 0.0133 Pa Boat temperature during vapor deposition 250 ° C Chlorine concentration 500ppm Second undercoat layer Raw material alloy SeAs (80%) Metal iodine (20%) Vacuum degree 0.0133Pa Boat temperature during vapor deposition 300 ° C Iodine concentration 20% Both of sample A and halogen If the concentration distribution is set higher on the charge generation layer side, good running characteristics can be obtained. Example 6 An aluminum alloy having the following composition was used to obtain a conductive substrate having a diameter of 30 mm and a length of 250 mm (Table 3).

[0036]

[Table 3] Further, the surface of the substrate was diamond-finished to have a maximum surface roughness of 0.5 micron.

An aqueous detergent (Lion MF
-10) Immerse in a 5% solution at a temperature of 50 ° C. for 3 minutes, perform ultrasonic cleaning, and then brush-clean with the same detergent,
The surface was cleaned by the steps of rinsing with purified water (addition of ultrasonic waves for 3 minutes), rinsing with pure water (3 minutes with addition of ultrasonic waves), rinsing with ultrapure water, and drying with warm pure water (temperature 70 ° C). Subsequently, an undercoat layer having the following composition was formed by dip coating to have a thickness of 2 μm.

Melamine resin (Mitsui Toatsu Chemicals: Uban 21R) 50 parts by weight Trimellitic anhydride (Wako Pure Chemicals Reagent) 7 parts by weight Iodine (Wako Pure Chemicals Reagent) 3 parts by weight Hydrophobic silica (Japan Aerosil) 40 parts by weight Methyl alcohol 700 parts by weight After this, the first heat treatment is dried at 100 ° C. for 20 minutes,
Further, the second heat treatment was performed at 140 ° C. for 20 minutes.

Further, an ultraviolet irradiation device (Sun Engineering Co., Ltd .; SUV200NS) was used to improve the adhesion for 20 seconds at a lamp-photosensitive member distance of 20 mm and a lamp voltage of 200V. The charge generation layer was dip coated with a coating solution having the following composition to a thickness of 0.1 micron. X-type metal-free phthalocyanine 1 part by weight Polyvinyl butyral 1 part by weight Tetrahydrofuran 98 parts by weight The charge transport layer was dip-coated with a coating solution having the following composition to a thickness of 20 μm.

5 parts by weight of hydrazone compound (Ananan fragrance: CTC191) 5 parts by weight of butadiene compound (Ananan fragrance: T-405) 10 parts by weight of polycarbonate resin (Teijin: C-1400) 80 parts by weight of dichloromethane As described above When a printing test was carried out by mounting the produced photoconductor on a laser beam printer, the initial print density was 1.42 (by a Macbeth densitometer), a blank paper density was 0.0.
5 (according to a Macbeth densitometer), and the number of black spots having a diameter of 0.1 mm or more was 4, which was good per one revolution of the drum. In addition, as a result of Gobangme test (JIS K5400), peeling is 0 /
It was as good as 100.

A running test of 100,000 sheets was carried out with this drum, and a printing test showed that the printing density was 1.4.
1, the white paper density was 0.06, the number of black dots was 5 and the differences from the initial stage were not found, and film peeling during the test did not occur. Furthermore, this photoconductor is placed in an environment of 60 ° C and 90% relative humidity for 1
After leaving for 500 hours, a printing test, a Gobangme test, and a running test were performed, and the same good results as before the leaving were obtained.

The iodine concentration in the undercoat layer of this drum was measured by an ion microanalyzer IMA, and as a result, it was about 2.5% on the side of the conductive substrate and 3.5% on the side of the charge generation layer. Comparative Example 2 A photoconductor was prepared under the same conditions as in Example 6 except that the drying and curing steps of the undercoat layer were changed to 140 ° C. and 1/20 step.

The iodine concentration in the undercoat layer of this drum was approximately uniform from the side of the conductive substrate to the side of the charge generation layer, and was about 3
%Met. However, there is a decrease in concentration on the outermost surface, about 2.6%
Was going down. Further, according to a printing test after running a 100,000-sheet running test with this drum, a decrease in print density and an increase in white paper density, that is, background fog were observed. It was clarified that the phenomenon was caused by the decrease of the charging position and the increase of the bright part potential due to the increase of the residual potential from the measurement result of the electric characteristics. That is, a photosensitive member in which the iodine concentration is not high on the charge generation layer side has a large characteristic variation due to repeated use. Example 7 A photoconductor was prepared in the same manner as in Example 6 except that the conductive substrate was replaced with PPS resin (containing carbon black) having a volume resistance of 100 Ω · cm.

When a printing test was carried out by mounting the photoconductor thus prepared on a laser beam printer, the printing density was 1.41 (by a Macbeth densitometer) and the white paper density was 0.06 (Macbeth density) at the initial stage. The total number of black dots having a diameter of 0.1 mm or more was as good as two per one round of the drum. In addition, Gobangme test (JIS K540
As a result of 0), the peeling was as good as 0/100.

Further, according to the printing test after the running test of 100,000 sheets was conducted with this drum, the printing density was 1.
40, white paper density of 0.06, and number of black dots of 3 were not found, and film peeling during the test did not occur. In addition, place this photoreceptor in an environment of 60 ° C and relative humidity of 90%.
After leaving for 500 hours, a printing test, a Gobangme test, and a running test were performed, and good results were obtained in the same manner as before leaving.

The iodine concentration distribution at this time was the same as in Example 6. Example 8 In the same manner as in Example 3, an undercoat layer was prepared in the same manner as in Example 3 to prepare a photoreceptor having a two-layer laminate of a first undercoat layer and a second undercoat layer having the combination of conditions shown in Table 4. The drying, curing temperature, and film thickness in that case are as follows.

First layer (substrate side) Second layer (charge generation side) Drying conditions 100 ° C., 20 minutes 100 ° C., 20 minutes Curing conditions 140 ° C., 20 minutes 140 ° C., 20 minutes Film thickness 9 μm 1 μm

[0048]

[Table 4] The evaluation results at this time are ⊚ 100,000 sheets, no problem, ∘ 100,000 sheets, no problem in practical use, Δ 70,000 sheets, no problem, and × 50,000 sheets, a decrease in density.

It is preferable if the iodine concentration on the charge generation layer side is higher than that on the conductive substrate side. Example 9 A photoreceptor was prepared under the same conditions as in Example 6 except that the composition of the undercoat layer was changed, and the same evaluation as in Example 6 was performed.

Sample C: Brominated epoxy resin (Sekisui Chemical; S-REC KS-1) 50 parts by weight Hydrophobic silica (Japan Aerosil) 50 parts by weight Tetrahydrofuran 700 parts by weight Sample D: Fluorine-containing comb polymer (Soken Chemical; LF40) 50 Part by weight Titanium oxide fine particles (Japan Aerosil) 50 parts by weight Tetrahydrofuran 700 parts by weight Sample E: PVC / vinyl acetate copolymer resin 50 parts by weight Titanium oxide fine particles (Japan Aerosil) 50 parts by weight Tetrahydrofuran 700 parts by weight Samples C, D, E All In, the good running characteristics could be obtained by setting the halogen concentration distribution so as to be higher on the charge generation layer side.

[0051]

According to the present invention, since the halogen concentration in the undercoat layer has a concentration gradient which increases from the surface in contact with the conductive substrate to the surface in contact with the photosensitive layer, good printing characteristics are obtained even after repeated use. Thus, an electrophotographic photoconductor without quality deterioration under high temperature and high humidity can be obtained.

Further, since the undercoat layer is composed of the first undercoat layer and the second undercoat layer, an electrophotographic photoreceptor having a halogen concentration gradient can be easily formed by using a plasma polymerization method, a vacuum deposition method or the like. Can be prepared. When a subbing layer containing halogen is formed on a conductive substrate and subjected to heat treatment for drying and curing, a subbing layer having a halogen concentration gradient can be easily obtained by diffusion of halogen in the subbing layer.

When the undercoat layer is formed and then immersed in a halogen-containing solution, the halogen diffuses into the undercoat layer to obtain an undercoat layer having a halogen concentration gradient.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a photoconductor for electrophotography.

[Explanation of symbols]

 1 Conductive Substrate 2 Undercoat Layer 3 Charge Generation Layer 4 Charge Transport Layer

Claims (6)

[Claims] 1. An electrophotographic photoreceptor comprising a halogen-containing undercoat layer and a photosensitive layer, which are sequentially laminated on a conductive substrate, wherein the halogen concentration in the undercoat layer is higher than that of the surface in contact with the conductive substrate. An electrophotographic photosensitive member having a concentration gradient increasing toward a surface in contact with a layer. 2. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer comprises a first undercoat layer having a relatively low halogen concentration and a second undercoat layer having a relatively high halogen concentration. An electrophotographic photoreceptor comprising two layers that are sequentially laminated. 3. In a method for producing an electrophotographic photoreceptor comprising a halogen-containing undercoat layer and a photosensitive layer, which are sequentially laminated on a conductive substrate, an undercoat layer coating solution containing an organic resin and halogen is electrically conductive. A method for producing an electrophotographic photosensitive member, which comprises the steps of forming an undercoat layer by applying a heat treatment on a transparent substrate, followed by a dry heat treatment and then a curing heat treatment of an organic resin. 4. A method for producing an electrophotographic photoreceptor comprising a halogen-containing undercoat layer and a photosensitive layer, which are sequentially laminated on a conductive substrate, to form a halogen-containing undercoat layer in an organic resin. A method for producing an electrophotographic photoreceptor, comprising the steps of: immersing the obtained undercoat layer in a halogen-containing solution. 5. An electrophotographic photoconductor in which a first undercoat layer having a relatively low halogen concentration, a second undercoat layer having a relatively high halogen concentration, and a photosensitive layer are sequentially laminated on a conductive substrate. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the first and second undercoat layers are formed by a plasma polymerization method using reaction gases containing different concentrations of halogen. 6. An electrophotographic photoconductor in which a first undercoat layer having a relatively low halogen concentration, a second undercoat layer having a relatively high halogen concentration, and a photosensitive layer are sequentially laminated on a conductive substrate. 2. The method for producing an electrophotographic photoreceptor, wherein the first and second undercoat layers are formed by vacuum vapor deposition using alloys containing different concentrations of halogen elements.