JP2817421B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member having excellent potential stability and image quality stability in repeated use.

[0002]

2. Description of the Related Art In an electrophotographic copying process using an organic photoreceptor, the surface of a photosensitive layer is charged by corona discharge or the like.
Next, when the image is exposed, the charges generated in the photosensitive layer move to the surface of the photosensitive layer to neutralize the charges on the surface of the photosensitive layer, and an electrostatic latent image corresponding to the image is formed. In that case,
In order to form an image having a constant image density and no fog when repeatedly used, an undercoat layer is provided between a conductive support and a photosensitive layer. As the material for forming the undercoat layer, various materials have been proposed so far.For example, it is known to use polyurethane, polyamide, polyvinyl alcohol, epoxy resin, casein, methylcellulose, phenol resin, and the like.
It is also known to use an alcohol-soluble nylon such as N-alkoxymethylated nylon as the polyamide (JP-A-58-95351).

[0003]

The electrophotographic photoreceptors provided with an undercoat layer, which have been proposed, do not yet have sufficient characteristics, and the residual potential may increase due to repeated charging and exposure. In addition, the undercoat layer resin deteriorates to lower the potential stability and image defects occur. Even when the above-mentioned alcohol-soluble nylon is used, at high temperature and high humidity, there is a problem that the resistance value is lower than that at normal temperature, and the potential stability is reduced. This causes a problem that image defects occur.

Accordingly, it is an object of the present invention to provide an electrophotographic photosensitive member having excellent potential stability and image quality stability during repeated use. Another object of the present invention is to provide an electrophotographic photoreceptor that is excellent in environmental stability without a decrease in resistance under high temperature and high humidity and does not cause image defects due to resin deterioration.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies and as a result, have found that an undercoat layer is formed on a conductive support by using an alcohol-soluble nylon represented by the following general formula (I) and a crosslinking agent. It has been found that the above object can be achieved by forming the above, and the present invention has been completed.

The present invention provides an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer formed on a conductive substrate, wherein the undercoat layer has a number average molecular weight of 5, represented by the following general formula (I):
000-50,000 alcohol-soluble nylon,
0.01 part by weight of the alcohol-soluble nylon
It is characterized by being formed by using 0.1 to 0.1 parts by weight of a crosslinking agent. (Wherein, R represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent,
l and m each represent an integer of 5 to 20, and n is 1 to
A means an integer of 5, and A means an integer of 20 to 80. )

Hereinafter, the present invention will be described in detail. FIG. 1 is a schematic sectional view of an example of the electrophotographic photosensitive member of the present invention. An undercoat layer 2 is provided on a conductive support 1, and a charge generation layer 3 and a charge transport layer 4 are sequentially provided thereon.

[0008] As the conductive support, aluminum,
Drums and sheets of metal such as copper, iron, zinc, nickel, etc.
Aluminum, copper, on paper, plastic or glass
Metal such as gold, silver, platinum, palladium, titanium, nickel-chromium, stainless steel, copper-indium, or a conductive metal compound such as indium oxide or tin oxide is deposited, or a metal foil is laminated. Or, a known material such as a drum, a sheet, and a plate, which has been subjected to a conductive treatment by dispersing carbon black, indium oxide, tin oxide-antimony oxide powder, metal powder, or the like in a binder resin and applying the same, is used. However, the present invention is not limited to these.

An undercoat layer is formed on the conductive support, and the resin used for the undercoat layer functions to prevent charge injection from the conductive support into the photosensitive layer during charging of the photosensitive layer. In addition, it has an action as an adhesive layer for adhering the photosensitive layer to the conductive support. In the present invention, alcohol-soluble nylon is used. The alcohol-soluble nylon used in the present invention has a number average molecular weight of 5,000 to 50, represented by the general formula (I).
, And specific examples thereof include N-methoxymethylated nylon-6, N-methoxymethylated nylon-8, and ethoxymethylated nylon-6.
And the like.

As a crosslinking agent, maleic acid, oxalic acid,
Tartaric acid, itaconic acid, hypophosphorous acid, malonic acid. The crosslinking agent is used in an amount of 0.01 to 0.1 part by weight, preferably 0.03 to 0.1 part by weight, per part by weight of the alcohol-soluble nylon.
Used in the range of 0.1 parts by weight. When the amount of the cross-linking agent is out of the above range, a problem occurs in that the potential stability and the image quality stability during repeated use deteriorate.

Examples of the solvent used for the coating liquid for forming the undercoat layer include methanol, ethanol, water, n-butanol and the like, and these can be used alone or in combination of two or more. As a method of applying the coating liquid for forming the undercoat layer, use a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, a curtain coating method, an air knife coating method, a rod coating method, or the like. Can be. The thickness of the undercoat layer is 0.0
About 5 to 20 μm is appropriate, and preferably 0.1 to 1 μm.
It is set in the range of 0 μm.

After application, the undercoat layer is dried by heating to 140 to 200 ° C., whereby the alcohol-soluble nylon undergoes the following reaction to have a three-dimensional structure, and has a low hygroscopic property. Resin deterioration does not occur.

[0013]

A photosensitive layer is provided on the undercoat layer.
The photosensitive layer may have a single layer structure, but preferably has a charge generation layer and a charge transport layer. The charge generation layer is formed by dispersing a charge generation substance in a binder resin, and is formed by dispersing the charge generation substance in a binder resin solution and applying the dispersion. As the charge generating substance, trigonal selenium, amorphous selenium, Se-As alloy, azo pigment such as monoazo-, disazo-, trisazo- or higher polyazo, polycyclic quinone pigment, perylene pigment, indigo pigment, Bisbenzimidazole pigments, phthalocyanine pigments, quinacridone pigments, pyrylium compounds, squarium compounds, cyanine pigments, quinocyanine pigments, trimethine compounds, azurenium compounds and the like can be used. Examples of the binder resin include polyester, polystyrene, cellulose fatty acid ester, poly (meth) acrylate,
Polyvinyl butyral, vinyl chloride-vinyl acetate copolymer and the like can be used.

These binder resins are used after being dissolved in an appropriate solvent. Examples of the solvent include methanol, ethanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, and acetic acid. Organic solvents such as methyl, dioxane, tetrahydrofuran, methylene chloride and chloroform can be used.

As a method for dispersing the charge generating substance in the binder resin solution, a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. At that time, it is effective that the charge generation material has a particle size of 5 μm or less, preferably 2 μm or less, and most preferably 0.5 μm or less. The thickness of the charge generation layer is generally 0.1 to 5
μm, preferably 0.2 to 1.0 μm. Further, as a coating method for forming the charge generation layer, a method similar to that exemplified in the case of forming the undercoat layer described above can be used.

The charge transporting layer is composed of a hole transporting substance and a binder resin, and is formed by applying a coating solution obtained by dissolving the hole transporting substance and the binder resin in an appropriate solvent. It is formed. As the hole transporting substance, a conventionally known substance can be used. For example, N-methyl-N-phenylhydrazino-3-methylidene-9-ethylcarbazole, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone and the like Hydrazones, 1-phenyl-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazolin, 1- [quinonyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylamino Pyrazolines such as phenyl) pyrazoline; oxazole compounds such as 2- (p-diethylaminostyryl) -6-diethylaminobenzoxazole; triarylmethane compounds such as bis (4-diethylamino-2-methylphenyl) -phenylmethane; N, N'-di Eniru -N,
And diamine compounds such as N'-bis- (m-tolyl)-[1,1'-biphenyl] -4,4'-diamine.

As the binder resin, those generally used such as polycarbonate, polyarylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, polymethacrylate, styrene-methacrylate copolymer and the like can be used. Used.

The compounding ratio of the hole transport material and the binder resin is 5:
It is about 1-1: 5, preferably about 3: 1 to 1: 3. When the former is too large, the mechanical strength of the charge transporting layer decreases, and when the former is too small, the sensitivity decreases.

As the solvent used for producing the coating solution for forming the charge transport layer, a solvent capable of dissolving both the hole transport material and the binder resin is used. For example, benzene, xylene, aromatic hydrocarbons such as chlorobenzene, acetone,
Commonly used organic solvents such as ketones such as 2-butanone, methylene chloride, chloroform, halogenated aliphatic hydrocarbons such as ethylene chloride, tetrahydrofuran, and cyclic or linear ethers such as ethyl ether;
They can be used alone or in combination of two or more. The thickness of the charge transport layer is generally 5 to 50 μm, preferably 1 to 50 μm.
0 to 30 μm is appropriate. In addition, as a coating method for forming the charge transport layer, a method similar to that exemplified in the case of forming the undercoat layer can be used.

[0021]

In the electrophotographic photoreceptor, when the undercoat layer is formed only of an electrically insulating resin, electric charges are accumulated in the undercoat layer, the residual potential increases, and the photocharge generated in the photosensitive layer is quickly discharged. In addition, it is not injected into the conductive support, and the sensitivity is reduced. In addition, when used repeatedly, the stress of the electrophotographic process of charging → exposure → development → transfer deteriorates the resin of the undercoat layer and changes the charge injecting property of the resin. Deterioration and image quality defects are likely to occur. However, in the present invention, since the undercoat layer is formed by adding a crosslinking agent to the alcohol-soluble nylon resin represented by the general formula (I), the alcohol-soluble nylon resin has a three-dimensional structure. Becomes
Since the influence of temperature and humidity on the resistance value of the resin is reduced, a change in characteristics due to a difference in environment is reduced. Also,
Since the deterioration stability is improved, a rise in the residual potential is prevented, charge injection is promptly performed, resin deterioration due to the stress of the electrophotographic process is prevented, and the potential stability and image quality stability are improved.

[0022]

The present invention will be described in more detail with reference to the following examples. In addition, “parts” means parts by weight. Example 1 N-methoxymethylated nylon (Lacamide 500
3. Dainippon Ink and Chemicals, Inc. [General formula (I)
Where A = 30, l = 5, m = 5, n = 1, R = CH ₃ ]
1 part and 0.05 part of maleic acid were added to and dissolved in a mixed solvent of 7 parts by weight of methanol and 3 parts of n-butanol to prepare a coating liquid for forming an undercoat layer. The obtained coating solution was treated with 84
mmφ × 310mm aluminum pipe
By heating at 70 ° C. for 10 minutes, an undercoat layer having a thickness of 1.0 μm was formed.

Next, a dispersion obtained by dispersing the following components in a sand mill using glass beads having a diameter of 1 mm for 15 minutes is applied on the undercoat layer by a dip coating method. After drying for a minute, a charge generation layer having a thickness of 0.3 μm was formed. X-type metal-free phthalocyanine 5 parts Polyvinyl butyral (XYHL, manufactured by Union Carbide) 5 parts Cyclohexanone 300 parts On the formed charge generating layer, N, N'-diphenyl-
1 part of N, N'-bis- (m-tolyl)-[1,1'-biphenyl] -4,4'-diamine and 1 part of a polycarbonate resin (Panlite LR50, manufactured by Teijin Chemicals Ltd.) A solution obtained by dissolving in 10 parts of monochlorobenzene was applied by a dip coating method, and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.

The obtained electrophotographic photosensitive member was charged by a 5.9 kV corona charger, and the potential at that time was measured.
Next, the light is attenuated by irradiating white light, and the exposure amount E (erg / cm ² ) and the potential attenuation amount at that time are measured, and the sensitivity d is measured.
V / dE was determined. After repeating the above operations of charging and irradiation of white light 1000 times, the charging potential and sensitivity at that time were similarly obtained. Table 1 shows the results. Using this electrophotographic photoreceptor, a copy operation was performed, and image quality evaluation was performed on images obtained when 10,000 copies were made. Table 1 also shows the results.

[0025]

[Table 1]

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that maleic acid was not contained in the undercoat layer, and evaluation was performed in the same manner. Table 1 shows the results.

Examples 2 to 7 Electrophotographic photosensitive members were prepared in the same manner as in Example 1 except that a crosslinking agent shown in Table 2 was added instead of maleic acid in Example 1, and evaluation was performed in the same manner. went. Table 2 shows the results.

[0028]

[Table 2]

Examples 8 and 9 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount of maleic acid added in Example 1 was changed to 0.01 part or 0.1 part. Was evaluated. Table 3 shows the results.

Comparative Examples 2 and 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount of maleic acid added in Example 1 was changed to 0.005 parts or 0.2 parts. Was evaluated. Table 3 shows the results.

[0031]

[Table 3]

As is clear from the above results, when no crosslinking agent was added to the undercoat layer, sensitivity, residual potential,
It can be seen that when the image quality retention is not good and the amount of addition is out of the above range, the chargeability and the repetition stability deteriorate.

[0033]

As is apparent from the above comparison, the undercoat layer of the electrophotographic photoreceptor of the present invention is formed by using the alcohol-soluble nylon represented by the general formula (I) and a predetermined amount of a crosslinking agent. As a result, it has excellent potential stability and image quality stability when used repeatedly, and it has excellent resistance to environmental resistance, especially under high temperature and high humidity, excellent environmental stability, and no image defects due to resin degradation. Has the effect. Therefore, the electrophotographic photoreceptor of the present invention is effectively used in an electrophotographic copying machine, and is further applicable to various printers, microfilm readers, electrophotographic plate making systems and the like to which xerography technology is applied.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive support 2 Undercoat layer 3 Charge generation layer 4 Charge transport layer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Makoto Kusanagi 1600 Takematsu Business, Fuji Xerox Co., Ltd., Fuji Xerox Co., Ltd. In-house (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5/14

Claims (2)

(57) [Claims] 1. An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer formed on a conductive substrate, wherein the undercoat layer comprises:
A number average molecular weight of 5,000 or more represented by the following general formula (I)
50,000 alcohol-soluble nylon and 0.01 to 0.1 part by weight per 1 part by weight of the alcohol-soluble nylon.
An electrophotographic photoreceptor formed using parts by weight of a crosslinking agent. (Wherein, R represents a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent,
l and m each represent an integer of 5 to 20, and n is 1 to
A means an integer of 5, and A means an integer of 20 to 80. ) 2. The electrophotographic photoreceptor according to claim 1, wherein the crosslinking agent comprises at least one selected from maleic acid, oxalic acid, glycolic acid, tartaric acid, itaconic acid, hypophosphorous acid, and malonic acid.