JPH04253062A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body improved in electrophotographic characteristics, such as potential stability at the time of repeated uses, especially, under high temperature and high humidity and enhanced in image characteristics. CONSTITUTION:The electrophotographic sensitive body is formed by laminating can a conductive substrate 1 an undercoat layer 4, an electric charge generating layer 2 and a charge transfer layer 3, and at least one of the undercoat layer 4 and the generating layer 2 is characterized by having a chlorine ion content of <=100ppm of the total solid amount of the layer 4 or the layer 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor that exhibits excellent potential stability and image quality maintenance stability during repeated use under high temperature and high humidity environments.

0002

[Prior Art] Various materials have been used and proposed for electrophotographic photoreceptors, but when an organic photoconductor is used, a functionally separated type electron material having a charge generation layer and a charge transport layer is used. Photographic photoreceptors are the mainstream. That is,
Since the functionally separated electrophotographic photoreceptor has a photosensitive layer divided into a charge generation layer and a charge transport layer, it is possible to expand the material selection criteria for each layer, and it also has non-polluting, high productivity, low cost, etc. Because of these advantages, in recent years it has been widely used as a photoreceptor not only in electrophotographic copying machines but also in printers and the like that use semiconductor lasers and the like as light sources. Various types of charge-generating materials, charge-transporting materials, and binder resins have also been proposed. On the other hand, such functionally separated electrophotographic photoreceptors include an undercoat layer between the conductive support and the photosensitive layer in order to improve the adhesion between the conductive support and the photosensitive layer or to improve charging properties. For example, polyvinyl butyral resin (JP-A-58-106
549), polyamide resin (JP-A-58-987)
39), alcohol-soluble nylon resin (JP-A-60-196766), water-soluble polyvinyl butyral resin (JP-A-60-232553), and the like have been proposed.

0003

[Problems to be solved by the invention] By the way, in conventional functionally separated electrophotographic photoreceptors, trace amounts of pigments and/or binder resins forming the charge generation layer and resins forming the undercoat layer are However, materials containing impurities are used. These impurities, especially chlorine ions, can alter the resin or corrode the conductive substrate, creating areas where charge can be easily injected. Repeated use in a high-humidity environment has the disadvantage that potential stability decreases, image quality maintenance stability decreases, and image defects such as sandy white spots or black spots occur. Therefore, the present invention has been made with the object of improving the above-mentioned problems in conventional electrophotographic photoreceptors. That is, an object of the present invention is to provide an electrophotographic photoreceptor having excellent image quality characteristics and improved electrophotographic properties such as potential stability during repeated use, particularly during repeated use in high temperature and high humidity environments. It is about providing.

0004

[Means for Solving the Problems] As a result of intensive research, the present inventors have determined that the chlorine ion concentration contained in the undercoat layer or charge generation layer is determined by the total solid content in the undercoat layer or charge generation layer. The inventors have discovered that the above object of the present invention can be achieved by reducing the content to 100 ppm or less, and have completed the present invention.

[0005] The present invention provides an electrophotographic photoreceptor in which an undercoat layer, a charge generation layer, and a charge transport layer are laminated on a conductive substrate. The chlorine ion concentration is 100 ppm or less based on the total solid content in the undercoat layer or charge generation layer.

The present invention will be explained in detail below. 1 and 2 are schematic diagrams showing the structure of the electrophotographic photoreceptor of the present invention, in which a charge generation layer 2, a charge transport layer 3, and an undercoat layer 4 are laminated on a conductive substrate 1, and an electron It constitutes a photographic photoreceptor. The charge transport layer 3 is electrically connected and has the function of receiving charge carriers injected from the charge generation layer and transporting these charge carriers to the surface in the presence of an electric field. In this case, the charge transport layer 3 may be laminated on the charge generation layer 2 (see FIG.
), or may be laminated thereunder (FIG. 2). However, the charge transport layer is preferably laminated on the charge generation layer.

[0007] As the conductive substrate, aluminum, copper,
Metal drums and sheets such as iron, zinc, nickel, etc., metals such as aluminum, copper, gold, silver, platinum, palladium, titanium, nickel-chromium, stainless steel, copper-indium on plastic, paper, plastic or glass. Drum-shaped, sheet-like, or plate-shaped drums, sheets, or plates that are conductively treated by vapor deposition, laminating metal foil, or dispersing carbon black, indium oxide, tin oxide-antimony oxide powder, metal powder, etc. in a binder resin and applying the coating. Well-known materials such as shapes can be used, but the material is not limited thereto.

[0008] The undercoat layer and the charge generation layer laminated on the conductive substrate are made of materials such as the charge generation agent of the charge generation layer (
By performing a purification treatment on the pigment (hereinafter referred to as pigment), the binder resin, and the resin of the undercoat layer, the concentration of chlorine ions as an impurity is reduced in advance to the total solid content in the charge generation layer and the undercoat layer. Use one that has been treated to remove chlorine ions to 100 ppm or less.

When the chlorine ion concentration in the charge generation layer and undercoat layer exceeds 100 ppm based on the total solid content in the charge generation layer and undercoat layer, the potential stability during repeated use decreases, resulting in fluctuations in chargeability and sensitivity. becomes larger. In addition, when used repeatedly under high temperature and high humidity environments, image defects such as sand-like white spots, white spots, black spots, or black spots occur on the image. However, if the chlorine ion concentration is 100 ppm or less based on the total solid content in the charge generation layer and undercoat layer, changes in chargeability and sensitivity during repeated use are small, potential stability is good, and high temperature and high humidity environments are possible. No image defects will occur during repeated use. Therefore, in the present invention, the chlorine ion concentration in the charge generation layer and undercoat layer is 100 pp.
m or less, preferably 50 ppm. Note that the chloride ion concentration was measured by chromatography analysis.

[0010] By setting the chlorine ion concentration to 100 ppm or less based on the total solid content in the charge generation layer and undercoat layer, potential stability during repeated use and image defects during repeated use under high temperature and high humidity environments can be improved. The reason for the improvement is presumed to be as follows. In other words, the reason why the potential stability is improved during repeated use is that during repeated use, the chlorine component in the charge generation layer and undercoat layer is ionized, changing the conductivity of the undercoat layer and charge generation layer themselves. This is by preventing a decrease in potential stability due to In addition, the reason why image defects caused by repeated use in high temperature and high humidity environments are improved is that due to repeated use in high temperature and high humidity environments, the chlorine components in the charge generation layer and undercoat layer are ionized, resulting in chlorine ions. This is because it moves toward the conductive substrate under the influence of the electric field, corrodes minute portions on the surface of the conductive substrate, and further prevents the generation of localized areas where charge is likely to be injected.

In order to keep the chlorine ions in the charge generation layer and undercoat layer within the above range, the pigment must be
This can be done by heating and stirring the crude pigment in deionized water to elute water-soluble impurities contained in the pigment, separating the pigment and water using a centrifuge, and then drying to remove the water. . In addition, for the binder resin of the charge generation layer and the resin of the undercoat layer, these resins are dissolved in a soluble solvent, and then dropped into deionized water and reprecipitated, and then removed by dehydration and drying. However, other methods may also be used.

As the resin used for the undercoat layer, a resin dechlorinated and ionized as described above is used, but it has the effect of preventing charge from being injected from the conductive substrate into the photosensitive layer when the photosensitive layer is charged. In addition, it is preferable to use a material that also functions as an adhesive layer that temporarily holds the photosensitive layer in close contact with the conductive substrate. Examples of such resins include polyethylene, polypropylene, acrylic resins, methacrylic resins, polyamide resins, alcohol-soluble nylon resins, vinyl chloride resins, vinyl acetate resins, phenolic resins, polycarbonate resins, polyurethane resins, polyimide resins, and chlorinated resins. Known resins such as vinylidene resin, polyvinyl acetal resin, water-soluble polyvinyl butyral resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol, water-soluble polyester, nitrocellulose, casein, gelatin, etc. can be used.

Solvents used in the coating solution for forming the undercoat layer include methanol, ethanol, water, n-butanol,
Examples include benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, dioxane, tetrahydrofuran, methylene chloride, and chloroform. These solvents can be used alone or in combination of two or more.

The thickness of the undercoat layer is suitably set to about 0.05 to 20 μm, preferably in the range of 0.1 to 10 μm. Methods for applying the coating liquid for forming the undercoat layer include blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, curtain coating method,
This can be done by using an air knife coating method, a rod coating method, a spray coating method, or the like.

In the present invention, the charge generation layer provided on the conductive substrate is composed of a pigment and a binder resin, and the pigment and binder resin are treated to remove chlorine ions as in the case of the undercoat layer. do. Pigments include inorganic pigments such as selenium and selenium compounds, zinc oxide, and cadmium sulfide, or azo pigments having a carbazole skeleton, azo pigments having a styrylstilbene skeleton, azo pigments having a triphenylamine skeleton, and azo pigments having a dibenzothiophene skeleton. Pigments, azo pigments with an oxadiazole skeleton, azo pigments with a fluorenone skeleton, azo pigments with a bisstilbene skeleton, azo pigments with a distyryloxazole skeleton, azo pigments with a distyrylcarbazole skeleton, metal-free substances with a carbazole skeleton Known organic pigments such as phthalocyanine pigments such as phthalocyanine pigments, quinone pigments such as anthrone and pyranthrone, quinacridone pigments, bisbenzimidazole pigments, perylene pigments, indigo pigments, squalium pigments, quinoline pigments, pyrylium salt pigments and azulenium salt pigments. Can be used. Binder resins for the charge generation layer include polyester, polystyrene, cellulose fatty acid ester, poly(meth)acrylate resin, polyvinyl butyral,
Polyvinyl formal, polyvinyl acetal, vinyl chloride-vinyl acetate copolymer, etc. can be used.

These binder resins are used after being dissolved in a suitable solvent, examples of which include methanol, ethanol, n-butanol, benzyl alcohol, methyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, and dioxane. , tetrahydrofuran,
Organic solvents such as methylene chloride and chloroform can be used. The blending ratio (weight ratio) of pigment and binder resin is 10
:1 to 1:10 is preferable. As a method for dispersing the charge generating substance in the binder resin solution, a ball mill dispersion method, an attritor dispersion method, and a sand mill dispersion method can be used. At this time, the charge generating substance has a diameter of 5 μm or less,
It is effective to set the particle size to preferably 2 μm or less, optimally 0.5 μm or less. The thickness of the charge generation layer is
Generally 0.1-5μm, preferably 0.2-1.0μm
m is appropriate. Further, as a coating method for forming the charge generation layer, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, a curtain coating method, etc. can be used.

In the present invention, any known charge transport layer can be used as the charge transport layer. For example, as a charge transport material, N
-Methyl-N-phenylhydrazino-3-methylidene-
Hydrazones such as 9-ethylcarbazole, p-diethylaminobenzaldehyde-N,N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone, 1-phenyl-3
-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl (2)
]-3-(p-diethylaminostyryl)-5-(p-
Pyrazolines such as diethylaminophenyl) pyrazoline, oxazole compounds such as 2-(p-diethylaminostyryl)-6-diethylaminobenzoxazole,
Triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, N,N
'-diphenyl-N,N'-bis-(m-tolyl)-[
By containing a diamine compound such as 1,1'-biphenyl]-4,4'-diamine in a film-forming binder resin, or by using a photoconductive polymer such as poly-N-vinylcarbazole or polyvinylanthracene. is used. As the binder resin, general binder resins such as polycarbonate, polyarylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, polymethacrylic acid esters, and styrene-methacrylic acid ester copolymer are used. The blending ratio of charge transport material and resin is 5:1 to 1:5, preferably 3:1 to 1:3.
That's about it. If the former is too large, the mechanical strength of the charge transport layer will be reduced, and if it is too small, the sensitivity will be reduced. The thickness of the charge transport layer is generally 5 to 50 μm.

[0018]

EXAMPLES Next, the present invention will be explained by examples. Example 1 As a pigment, 1 part of X-type metal-free phthalocyanine (parts by weight, same hereinafter) was added to 50 parts of deionized water with stirring,
The mixture was stirred while heating at 80° C. for 1 hour to elute water-soluble impurities contained in the pigment. Then, using a centrifuge (Kokusan Centrifuge Co., Ltd. refrigerated high-speed centrifuge H-251),
Centrifugation was performed at 0,000 RPM for 20 minutes, and pigment and water were separated by decanting. Then, dry the pigment in a vacuum dryer (
Drying was performed at 80° C. for 10 hours to remove moisture using a vacuum constant temperature dryer DP32 (manufactured by Yamato Scientific Co., Ltd.). On the other hand, 1 part of polyvinyl butyral resin (trade name: S-LEC BH-3, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 19 parts of ethanol. This container was slowly dropped into 100 parts of deionized water to precipitate the resin. Next, the precipitated resin was separated by filtration, and dried using a vacuum dryer in the same manner as pigment drying to remove ethanol and water. To a solution in which 1 part by weight of the purified polyvinyl butyral resin thus obtained was previously dissolved in 100 parts of cyclohexanone, 3 parts by weight of the purified X-type metal-free phthalocyanine was mixed,
The mixture was dispersed in a sand mill for 20 hours and diluted with cyclohexanone to prepare a coating solution for forming a charge generation layer having a solid content concentration of 3% by weight. On the other hand, a methanol/butanol mixed solution of 8-nylon resin (trade name: Laccamide 5003, manufactured by Dainippon Ink and Chemicals Co., Ltd.) was applied onto an aluminum pipe of 40 mmφ x 319 mm to form a 1.0 μm thick layer. A pull layer was formed, and the above dispersion was applied thereon using a ring coater, followed by heat drying at 120° C. for 10 minutes to form a charge generation layer with a thickness of 0.3 μm. A charge transport layer was formed thereon. That is, N,N'-diphenyl-N
, N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine as a charge transport substance, and 6 parts of polycarbonate Z resin are both dissolved in 40 parts of monochlorobenzene. The obtained solution was applied by dip coating method and dried at 110°C for 1 hour to form a film with a thickness of 20 μm.
It was used as a charge transport layer.

The obtained electrophotographic photoreceptor was charged with a 5.9 kV corona charger, the potential at that time was measured, and then white light was irradiated to attenuate the light, and the exposure amount E at that time was measured.
(erg/cm2) and potential attenuation, and sensitivity d
V/dE was determined. After repeating the above-mentioned charging and white light irradiation operations 500 times, the charging potential and sensitivity at that time were determined in the same manner. In addition, this electrophotographic photoreceptor was mounted on a laser beam printer (XP-11, manufactured by Fuji Xerox Co., Ltd.), and reverse development was performed using a negatively charged developer under a high temperature and high humidity environment (30°C, 90°C). %RH), 10,000 sheets were printed and the image quality of the printed images was examined. The results are shown in Table 1.

In order to measure the chloride ion concentration in the charge generation layer of the electrophotographic photoreceptor, the charge generation layer was peeled off to obtain a 0.6 g sample. This sample is JIS K2
NaOH/H2O by combustion tube air method according to 54
2 After absorbing the chlorine ion component into the absorption liquid, ion chromatography (Model 2000i manufactured by Dionex)
was used to measure the amount of chlorine ions contained in 0.6 g of the sample, and the chlorine ion concentration in the charge generation layer was calculated using the absolute calibration curve method. As a result, the chlorine ion concentration in the charge generation layer was 80 ppm.

Example 2 The purification treatment conditions for X-type metal-free phthalocyanine were as follows: 60°C;
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the heating and stirring was changed to heating and stirring for 1 hour, and evaluation was performed in the same manner. The results are shown in Table 1. In addition, when the chlorine ion concentration in the charge generation layer was measured at this time, it was found to be 89pp.
It was m.

Example 3 The purification treatment conditions for X-type metal-free phthalocyanine were as follows: 80°C;
An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the heating and stirring was changed to 3-hour heating and stirring, and evaluation was performed in the same manner. The results are shown in Table 1. In addition, when the chlorine ion concentration in the charge generation layer was measured at this time, it was found to be 63.
It was ppm.

Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the X-type metal-free phthalocyanine was used without purification, and evaluated in the same manner. The results are shown in Table 1. Further, when the chlorine ion concentration in the charge generation layer was measured at this time, it was 170 ppm.

Comparative Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the polyvinyl butyral resin was used without being purified, and evaluated in the same manner. Table 1 shows the results.
Shown below. Further, when the chlorine ion concentration in the charge generation layer at this time was measured, it was 103 ppm.

Comparative Example 3 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the X-type metal-free phthalocyanine was used without purification treatment and the polyvinyl butyral resin was used without purification treatment. Table 1 shows the results of the evaluation. Further, when the chlorine ion concentration in the charge generation layer at this time was measured, it was 268 ppm.

[0026]

[Table 1]

As is clear from the results in Table 1 above, when the chlorine ion concentration in the charge generation layer is lower than 100 ppm, the stability of potential and sensitivity during repeated use is improved, and repeated use under high temperature and high humidity environments is improved. The image quality is also good, but if it exceeds 100 ppm, the image quality deteriorates, especially after repeated use in high temperature and high humidity environments, fogging or black spots appear, and the chlorine ion concentration increases. Accordingly, potential stability also decreases.

Example 4 A polyamide resin, which is a copolymerized nylon of nylon 6/66/610/12, was prepared, and one part of it was mixed with ethanol 19
The mixture was heated and stirred at 60° C. for 1 hour to dissolve. This solution was slowly added dropwise to 100 parts of deionized water to precipitate the resin. Next, the precipitated resin was filtered and dried at 60° C. for 10 hours using a vacuum dryer (Yamato Scientific Co., Ltd., vacuum constant temperature dryer DP32) to remove ethanol and water. 10 parts of the purified copolymerized nylon resin thus obtained was dissolved in a methanol/toluene mixed solution,
It was applied to a 4 mmφ x 310 mm aluminum pipe using a dip coating method, and dried with hot air at 135°C for 10 minutes.
A subbing layer having a thickness of 0.8 μm was formed. Next, dibromanthanthrone pigment (
C. I. 8 parts of Pigment Red 168) were mixed. Furthermore, dispersion was carried out using a sand mill using 1 mmφ glass beads as a dispersion medium, and after dispersion, cyclohexanone was added to prepare a coating liquid having a solid content concentration of about 10% by weight. This coating solution was applied onto the undercoat layer by a dip coating method, and 1
Dry by heating at 00℃ for 10 minutes to obtain a film thickness of 0.8μm.
A charge generation layer was formed. A charge transport layer was formed thereon. That is, N,N'-diphenyl-N,N'-bis(3
-methylphenyl)-[1,1'-biphenyl]-4,
5 parts of 4'-diamine as a charge transport substance was dissolved in 40 parts of monochlorobenzene together with 6 parts of polycarbonate Z resin, and the resulting solution was applied by dip coating method.
It was dried at 0° C. for 1 hour to obtain a charge transport layer with a thickness of 20 μm.

The obtained electrophotographic photoreceptor was charged with a 5.9 kV corona charger, the potential at that time was measured, and then white light was irradiated to attenuate the light, and the exposure amount E at that time was measured.
(egr/cm2) and potential attenuation, and sensitivity d
V/dE was determined. After repeating the above-mentioned charging and white light irradiation operations 500 times, the charging potential and sensitivity at that time were determined in the same manner. In addition, using this electrophotographic photoreceptor, a copying machine (FX50 manufactured by Fuji Xerox Co., Ltd., manufactured by Fuji Xerox Co., Ltd.) was used in a high temperature and high humidity environment.
14), and the image quality was evaluated for the images obtained when 10,000 copies were made. The results are shown in Table 2. In order to measure the chlorine ion concentration in the undercoat layer of this electrophotographic photoreceptor, the undercoat layer was peeled off to obtain a 0.6 g undercoat layer sample. This sample was analyzed using the combustion tube air method in accordance with JIS K254.
After absorbing the chlorine ion component into the OH/H2O2 absorption liquid, ion chromatography (manufactured by Dionex,
2000i model) to measure the amount of chlorine ions contained in 0.6 g of the sample, and calculate the chlorine ion concentration in the undercoat layer using the absolute calibration curve method.

Comparative Example 4 Except that the copolymerized nylon resin was not purified.
An electrophotographic photoreceptor was produced in the same manner as in Example 4, and the same evaluation was performed. Further, the chloride ion concentration in the undercoat layer of the electrophotographic photoreceptor at this time was also measured in the same manner as in Example 4. The results are shown in Table 2.

[0030]

[Table 2]

As is clear from the results in Table 2 above, an electrophotographic photoreceptor with a low chloride ion concentration in the undercoat layer has excellent transfer stability during repeated use, and can be used repeatedly under high temperature and high humidity environments. Good image quality can also be obtained.

Example 5 Alcohol-soluble copolymer nylon (CK-4000,
(manufactured by Toray Industries, Inc.) was purified in the same manner as in Example 4. 1 part of the obtained purified copolymerized nylon resin was dissolved in 9 parts of methanol to prepare a coating solution for forming an undercoat layer, and the coating solution was applied onto a 40 mmφ x 319 mm aluminum pipe by a dip coating method. , an undercoat layer with a thickness of 1.0 mm was formed. Next, X
Three parts of type-free metal phthalocyanine were mixed, dispersed in a sand mill for 20 hours, and diluted with cyclohexanone to prepare a coating solution for a charge generation layer having a solid content concentration of 3% by weight. This coating solution was applied onto the undercoat layer by a dip coating method.
It was heated and dried at ℃ for 10 minutes to form a charge generation layer having a thickness of 0.30 μm. The charge transport layer coating liquid used in Example 4 was applied thereon by dip coating. It was dried at 110° C. for 1 hour to form a charge transport layer with a thickness of 20 μm, thereby obtaining an electrophotographic photoreceptor.

The electrophotographic photoreceptor was equipped with a scorotron charger with a grid applied voltage of -800 V, an exposure optical meter using a 780 nm laser diode, a reversal developing system, a developing device,
It was installed in an electrophotographic copying machine equipped with a transfer charger, a static elimination exposure optical system, and a cleaner. This electrophotographic copying machine was configured to produce an image on transfer paper as the photoreceptor was driven. Using this electrophotographic copying machine, dark potential (VH
) is set to approximately -800V, then the initial bright area potential (VL) (30erg/cm2 exposure) and dark area potential (VH), and the bright area potential (VL) and dark area potential after 1000 uses. Potential (VH) was measured. Also,
This electrophotographic copying machine was installed in a constant temperature and humidity room set at 30°C and 90% RH, and copy operations were performed for 20 minutes.
Image quality was evaluated for the images obtained when ,000 copies were made. The results are shown in Table 3. Further, the chlorine ion concentration in the undercoat layer of the electrophotographic photoreceptor at this time was measured in the same manner as in Example 4, and found to be 91 ppm.

Comparative Example 5 The alcohol-soluble copolymerized nylon used in Example 5 was dissolved in ethanol in the same manner as in Example 4, and this solution was dropped into tap water instead of deionized water. It was treated and purified in the same manner as in Example 4. An electrophotographic photoreceptor was produced in the same manner as in Example 5, except that the resin thus obtained was used, and the same evaluation was performed. The results are shown in Table 3. Further, the chlorine ion concentration in the undercoat layer of the electrophotographic photoreceptor at this time was measured in the same manner as in Example 4, and was found to be 114 ppm.
Met.

Comparative Example 6 An electrophotographic photoreceptor was prepared in the same manner as in Example 5, except that the alcohol-soluble copolymerized nylon was not purified, and the same evaluation was performed. Table 3 shows the results.
Shown below. Further, the chlorine ion concentration in the undercoat layer of the electrophotographic photoreceptor at this time was measured in the same manner as in Example 4, and found to be 381 ppm.

[0036]

[Table 3]

As is clear from the results in Table 3 above, when the chlorine ion concentration in the undercoat layer is 100 ppm or less, the potential stability during repeated use is good, and it does not recur in high temperature and high humidity environments. The image quality during use is good. 100p
If it exceeds pm, black sand-like black dots will appear as image quality defects during repeated use in high-temperature, high-humidity environments in the case of reverse development, and as the chlorine ion concentration further increases, the image quality defects will worsen and the black dots will become black spots. The potential stability during repeated use also decreases.

[0038]

Effects of the Invention As is clear from the results in the above table, the electrophotographic photoreceptor of the present invention has a chlorine ion concentration lower than 100 ppm in at least one of the charge generation layer and the undercoat layer. Because of this, it has excellent potential stability during repeated use, and when used repeatedly under high temperature and high humidity environments, it is possible to prevent the occurrence of image defects and form high quality images.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an embodiment of a first type electrophotographic photoreceptor of the present invention.

FIG. 2 is a schematic cross-sectional view of an embodiment of a second type of electrophotographic photoreceptor of the present invention.

[Explanation of symbols]

1. ．． ．． ．． conductive substrate, 2. ．． ．． ．． charge generation layer; 3. ．．
．． ．． charge transport layer, 4. ．． ．． ．． Undercoat layer

Claims (4)

[Claims] 1. An electrophotographic photoreceptor comprising an undercoat layer, a charge generation layer, and a charge transport layer laminated on a conductive substrate, wherein chlorine is contained in at least one of the undercoat layer and the charge generation layer. An electrophotographic photoreceptor characterized in that the ion concentration is 100 ppm or less based on the total solid content in the undercoat layer or the charge generation layer. 2. The pigment of the charge generation layer is one that has been heated and stirred in deionized water, separated from water using a centrifuge, dried, and purified. electrophotographic photoreceptor. 3. The binder resin of the charge generation layer is purified by dissolving a crude binder resin in a soluble solvent, dropping it into deionized water, and re-precipitating it. 1. The electrophotographic photoreceptor according to 1. 4. The resin of the undercoat layer is purified by dissolving a crude binder resin in a soluble solvent, dropping it into deionized water, and re-precipitating it. The electrophotographic photoreceptor described above.