JPH11311876A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoreceptor having high mechanical strength, a good electric resistance characteristic by electrostatic charge and good image flow evaluation by incorporating at least one of a polyarylate resin having a specific structural unit or a polycarbonate resin having a weight average mol.wt. below a specific value into a surface layer. SOLUTION: This electrophotographic photoreceptor contains at least one among the polyarylate resin which has the weight average mol.wt. of >=3.7×10<4> and has the structural unit expressed by the formula and the polyarylate resin which has the weight average mol.wt. of 3.7×10<4> and has the structural unit expressed by the formula or the polycarbonate resin having the weight average mol.wt. below 3.7×10<4> in the surface layer of the electrophotographic photoreceptor. In the formula, X is a substd. or unsubstd. cycloalkylidene group, substd. or unsubstd. α,ω-alkylene group, etc. R1 to R12 are the same or different and are hydrogen atoms, halogen atoms, substd. or unsubstd. alkyl group, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention also relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus. More specifically, the present invention relates to an electrophotographic photosensitive member having a surface layer containing a specific resin, and electrophotography. The present invention relates to a process cartridge having a photoconductor and an electrophotographic apparatus.

[0002]

2. Description of the Related Art In recent years, electrophotographic photosensitive members having various organic photoconductive compounds have been actively developed in recent years. For example, U.S. Pat. No. 3,838,851 discloses a photoreceptor having a charge transport layer containing triallyl pyrazoline, and U.S. Pat. No. 3,871,880 discloses a charge generating layer comprising a derivative of a perylene pigment and a condensate of 3-propylene and formaldehyde. And the like containing a charge transport layer.

[0003] The organic photoconductive compound has a sensitive wavelength range depending on the compound.
JP-A-72754 and JP-A-56-167759 disclose compounds having high sensitivity in the visible region, and JP-A-57-19567 and JP-A-69-16759.
Japanese Patent Application Laid-Open No. 1-228453 discloses a compound having high sensitivity in the infrared region.

[0004] Of these materials, those exhibiting sensitivity in the infrared region are used in laser beam printers (hereinafter abbreviated as LBP) and LED printers, and the demand frequency is increasing.

On the other hand, it is needless to say that an electrophotographic photosensitive member is required to have sensitivity, electric characteristics, and optical characteristics according to an applied electrophotographic process. In particular, since the surface of the electrophotographic photosensitive member that is repeatedly used is directly applied with electrical and mechanical external forces such as charging, exposure, development, transfer, and cleaning, durability against the external force is also required.

Specifically, there is a demand for durability against electrical deterioration due to ozone or nitrogen oxides generated during charging, mechanical deterioration such as surface abrasion and scratches due to discharging and cleaning during charging, and electrical deterioration. I have.

Further, in recent years, by applying a voltage to a charging member disposed in contact with an electrophotographic photosensitive member as disclosed in JP-A-57-17826 and JP-A-58-40566, There is also a problem caused by contact charging means for charging the electrophotographic photosensitive member.

The contact charging means generates much less ozone than a scorotron or the like. The scorotron is wasted because about 80% of the current flowing to the charger flows through the shield, whereas the contact charging means wastes this waste. It has the advantage of being very economical without any. However, since the charging member is in contact with the electrophotographic photosensitive member, the electrophotographic photosensitive member is required to have higher mechanical strength. In addition, for contact charging, a voltage in which an AC voltage is superimposed on a DC voltage has been devised for the purpose of improving charging stability due to charging by discharge (Japanese Patent Laid-Open No. 63-149668).

According to this charging system, the charging stability is improved, but the amount of current flowing through the electrophotographic photosensitive member is greatly increased due to the superposition of AC, so that the shaving amount of the electrophotographic photosensitive member is increased. A new problem has arisen, requiring not only mechanical strength but also electrical strength.

[0010]

In the case where the amount of abrasion of the surface layer is reduced due to the improvement of the durability characteristics, or the case where the surface roughness is increased by use even if the amount of abrasion is relatively large, the contact charging method is mainly used. When using paper that has sufficiently absorbed moisture under high temperature and high humidity, the oxidized and deteriorated resin and surface deposits cannot be completely removed, causing a decrease in surface resistance and the resulting image becoming unclear as if it were flowing. It has become clear that a problem (hereinafter referred to as image deletion) occurs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional surface layer, and to provide an electrophotographic apparatus having high mechanical strength, good electric resistance due to charging, and good image deletion evaluation. An object of the present invention is to provide a photoconductor, a process cartridge having an electrophotographic photoconductor, and an electrophotographic apparatus.

Another object of the present invention is to improve the abrasion resistance and smoothness of the surface layer of a photoreceptor, to provide a long-life, high-quality electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic photoreceptor. It is to provide a device.

[0013]

According to the present invention, there is provided an electrophotographic photosensitive member having a conductive support and a photosensitive layer, and a voltage which is placed in contact with the electrophotographic photosensitive member and which is obtained by superimposing an AC voltage on a DC voltage. In the electrophotographic apparatus having a charging member for charging the electrophotographic photoreceptor, the surface layer of the electrophotographic photoreceptor has a weight average molecular weight of 3.7 × 10 ⁴ or more and is represented by the following formula (1): polyarylate resin having the unit, and having a weight average molecular weight of polyarylate resin or less than 3.7 × 10 ⁴ having a structural unit represented by the following formula (1) having a weight average molecular weight of less than 3.7 × 10 ⁴ An electrophotographic photoreceptor containing at least one of polycarbonate resins is provided.

[0014]

Embedded image In the formula, X is —CR ₁₃ R ₁₄ — (where R ₁₃ and R ₁₄ are the same or different and are a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group) A substituted or unsubstituted cycloalkylidene group, a substituted or unsubstituted α, ω-alkylene group, a single bond, -O-, -S-, -SO-, or-
SO ₂ —. R _{1 to} R ₁₂ are the same or different and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

In the formula, the alkyl group is a methyl group,
Examples include an ethyl group, a propyl group, a cyclohexyl group and a cycloheptyl group. Examples of the aryl group include a phenyl group, a naphthyl group and an anthryl group. Examples of the cycloalkylidene group include a cyclohexylidene group, a cycloheptylidene group, and a fluorenylidene group. Examples of the α, ω-alkylene group include a 1,2-ethylene group, a 1,3-propylene group, and a 1,4-butylene group. Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

The substituents which these groups may have include halogen atoms such as fluorine, chlorine and bromine, alkyls such as methyl, ethyl and propyl, phenyl, naphthyl and anthryl. And an aralkyl group such as a benzyl group and a phenethyl group, and an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group.

The single bond means that the benzene rings on both sides of X are directly bonded.
Examples of the constituent units 7, 23 and 24 described above are given.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electrophotographic photosensitive member according to the present invention
By selecting and using at least one of a specific resin having particularly excellent durability properties and a resin having excellent wear properties as a resin forming the surface layer, excellent mechanical strength and electric resistance due to electrification are maintained. In addition, it has good electrophotographic characteristics for evaluation of image deletion.

In general, the strength of a resin increases with an increase in the molecular weight. However, the resin used in the present invention can achieve an electrophotographic photoreceptor having excellent durability while maintaining excellent durability characteristics by combining materials having different molecular weights. This is because the surface is more smoothly abraded than a conventional photoreceptor by using a mixture of a high molecular weight resin having excellent durability characteristics and a low molecular weight resin having excellent wear properties. As a result, it is considered that the surface adhering material which is considered to be one of the causes of the image deletion and is deteriorated by the charge is hardly attached.

Therefore, it is necessary for the resin used in the present invention that has a high molecular weight to have excellent durability characteristics. Specifically, it has a weight average molecular weight of 37000 or more, and preferably has a weight average molecular weight of 37000 to 300000, and particularly preferably 45,000 to 45,000.
More preferably, it has a weight average molecular weight of 250,000. When the weight average molecular weight is less than 37000, sufficient strength cannot be obtained, and it is difficult to achieve both durability and image deletion.
On the other hand, if the weight average molecular weight is more than 300,000, the viscosity of the coating material increases, which tends to lower the handling property of the coating material and deteriorate the coating property.

Further, it is necessary that a material having a small molecular weight can impart a suitable wear property. Specifically, 3
Has a weight average molecular weight of less than 7000,
It preferably has a weight average molecular weight of at least 37,000 and less than 37,000, and more preferably has a weight average molecular weight of 7,500 to 30,000. 7500 weight average molecular weight
If it is smaller than the above range, the strength is too large to cause damage due to repeated use, and further, the effect on image deletion tends to be insufficient due to the influence. The weight average molecular weight is 3
If it is 7000 or more, it becomes impossible to impart a suitable abrasion property, and the effect on image deletion becomes insufficient.

The term "dispersion degree" as used herein means the weight average molecular weight /
It is a value represented by a number average molecular weight. As for the degree of dispersion of these resins, the resin having a weight average molecular weight of 37000 or more is preferably 4.0 or less, more preferably 3.5 or less.
It is as follows. If the degree of dispersion is greater than 4.0, the proportion of those having a smaller molecular weight is increased, so that it is difficult to obtain sufficient strength, and shaving unevenness tends to occur. Also, 37
The degree of dispersion of the resin having a weight average molecular weight of less than 000 is 3.
It is preferably 0 or less, more preferably 2.6 or less.
When the degree of dispersion is greater than 3.0, the proportion of small particles having a high molecular weight increases, causing a decrease in strength. As a result, scratches are liable to occur due to repeated use. It tends to be insufficient.

Specific examples of the structural unit of the polyarylate resin having the structural unit represented by the formula (1) used in the present invention are shown in Tables 1 to 3, but are not limited thereto.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

Preferred examples are structural unit examples 1, 2,
3, 4, and 9 are preferred, and structural unit examples 1 and 4 are more preferred.

The polyarylate resin having a constitutional unit represented by the formula (1) used in the present invention is usually used for improving the solubility of a bisphenol represented by the following formula (2), so that terephthalic acid chloride / isophthalic acid chloride is used. Interfacial polymerization can be carried out by stirring in a solvent / water system under a mixture of the above and an alkali.

[0029]

Embedded image (Wherein X is -CR ₉ R _10- [where R ₉ and R ₁₀ are the same or different and are a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. ], A substituted or unsubstituted cycloalkylidene group, a substituted or unsubstituted α, ω-alkylene group, a single bond, -O-, -S-, -SO-, or-
SO ₂ —. R _{1 to} R ₈ are the same or different and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.

The ratio of terephthalic acid chloride to isophthalic acid chloride is determined in consideration of the solubility of the polymer, and is not defined. However, if any chloride is 30mo
Care must be taken when the content is 1% or less, since the solubility of the synthesized polymer is extremely reduced. Usually, it is preferable to synthesize at a ratio of 1/1.

In the electrophotographic photoreceptor of the present invention,
A polymer composed of the same structural unit represented by the formula (1) or a copolymer composed of two or more different types of structural units represented by the formula (1) may be used. Further, two or more resins having the structural unit represented by the formula (1) may be blended.

The polycarbonate resin used in the present invention can be polymerized by reacting bisphenol represented by the formula (2) with phosgene in the presence of an alkali. Specific examples of the polycarbonate resin used in the present invention include those having a bisphenol structure shown in Tables 1 to 3, but are not limited thereto. In the electrophotographic photoreceptor of the present invention, a polymer in which the structural units represented by the formula (2) are the same,
A copolymer composed of two or more different types of structural units represented by the formula (2) may be used. Further, two or more resins having the structural unit represented by the formula (2) may be blended.

The proportion of these resins depends on the type and molecular weight of each resin, but preferably contains 5 to 90% by weight, more preferably 10 to 80% by weight, of a resin having a weight average molecular weight of 37000 or more. More preferably. Further, if necessary, it may be used by mixing with other resins. However, when mixed with a resin other than the resin of the present invention, the resin of the present invention is 5% of the total binder resin.
0% by weight or more, preferably 70% by weight
More preferably, it is included. If the amount is less than 50% by weight, the effect on durability and image deletion in the present invention tends to be insufficient. If necessary, additives such as a lubricant and an antioxidant may be added.

The polyarylate resin having a structural unit represented by the formula (1) according to the present invention contains a unit having rigidity in the structural unit, and the unit is partially vitrified at the time of forming an electrophotographic photosensitive member. This increases the mechanical strength of the entire polymer coating.

Regarding the electric resistance, it is considered that the arylate structure in which the molecular cleavage due to electrical deterioration is an ester bond of an aryl group is stronger than the carbonate bond in the current due to charging, and the electric resistance is particularly improved. Although the reason for this has not been confirmed, it is assumed that the carbonate bond has a large dipole moment due to oxygen atoms on both sides of the carboxy group and is weak against electric energy.

Hereinafter, the configuration of the electrophotographic photosensitive member used in the present invention will be described. The electrophotographic photoreceptor in the present invention may be a single-layer type in which the photosensitive layer contains a charge transport material and a charge generation material in the same layer, or may be a laminate type in which a charge transport layer and a charge generation layer are separated. From the standpoint of electrophotographic characteristics, a laminated type is preferable.

The conductive support to be used is not limited as long as it has conductivity.
Alternatively, metal, paper, plastic, or the like provided with a conductive layer may be mentioned, and the shape may be a sheet, a cylinder, or the like.

When the image input is laser light such as LBP, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering or covering a scratch on the support. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is 5
４０40 μm, preferably 10-30 μm is suitable.

An intermediate layer having an adhesive function is provided thereon. As the material of the intermediate layer, polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose,
Casein, polyurethane, polyether urethane and the like. These are applied by dissolving in an appropriate solvent.
The thickness of the intermediate layer is 0.05 to 5 μm, preferably 0.3 to 5 μm.
1 μm is appropriate.

The charge generation layer is formed on the intermediate layer.
Examples of the charge generation material used in the present invention include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine, anthantrone, dibenzopyrene quinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments. No.

In the case of the function-separated type, the charge-generating layer comprises a homogenizer, an ultrasonic disperser, a ball mill, a vibrating ball mill, a sand mill, an attritor, a roll mill and a liquid containing the charge-generating material together with 0.3 to 4 times the amount of a binder fat and solvent. It is well dispersed by a method such as a collision type high-speed disperser, and a dispersion is applied and dried to form a dispersion. The thickness of the charge generation layer is 5 μm
Hereinafter, preferably, 0.1 to 2 μm is appropriate.

The charge transport layer is formed by coating and drying a coating material in which the binder resin of the present invention and the charge transport material are dissolved in a solvent. Examples of the charge transport material used include a triarylamine compound, a hydrazone compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound.

These charge transporting materials are combined with a binder resin in an amount of 0.5 to 2 times the amount thereof, applied and dried to form a charge transporting layer. The thickness of the charge transport layer is 5 to 40 μm, preferably 15 to 30 μm.

The charging member used in the present invention is not particularly limited as long as it is a contact charging member that is arranged in contact with the electrophotographic photosensitive member, and may be any of a roller shape, a blade shape and a brush shape. The voltage applied to the charging member is preferably such that a DC voltage has an absolute value of 200 to 2000 V, and an AC voltage has a peak-to-peak voltage of 400 to 2000 V.
It is preferable that the frequency is 200 to 3000 Hz at 〜4000 V. The image exposure unit, the development unit, the transfer unit, and the cleaning unit are not particularly limited.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.

In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 2 at a predetermined peripheral speed in a direction indicated by an arrow. The photoreceptor 1 receives a uniform charge of a predetermined positive or negative potential on the peripheral surface thereof by the primary charging means 3 during the rotation process, and then receives a charge from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure. It receives image exposure light 4. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then transferred to developing means 5
The toner-developed image developed by the toner image is transferred from a paper supply unit (not shown) between the photoconductor 1 and the transfer unit 6 in synchronization with the rotation of the photoconductor 1 and fed to a transfer material 7 fed therefrom. The image is sequentially transferred by the transfer unit 6. The transfer material 7 having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixation, so that it is printed out of the apparatus as a copy.

After the transfer of the image, the surface of the photoreceptor 1 is cleaned by removing the untransferred toner by the cleaning means 9, and is further cleaned by a pre-exposure light 10 from a pre-exposure means (not shown).
Is used for image formation repeatedly after the charge removal processing. In the present invention, since the primary charging means 3 is a contact charging means using a charging roller or the like, the pre-exposure is not necessarily required.

In the present invention, a plurality of components such as the above-described electrophotographic photosensitive member 1, primary charging means 3, developing means 5, and cleaning means 9 are integrally connected as a process cartridge. The process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported together with the photoreceptor 1 to form a cartridge, which can be attached to and detached from the apparatus main body using a guide unit such as a rail 12 of the apparatus main body. Process cartridge 1
It can be 1.

When the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is reflected and transmitted from the original, or the original is read by a sensor and converted into a signal. Laser beam scanning,
Light emitted by driving the LED array, driving the liquid crystal shutter array, and the like.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine but also for a laser beam printer,
It can be widely used in electrophotographic applications such as RT printers, LED printers, liquid crystal printers, and laser plate making.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a description of embodiments. In the examples, "parts" indicates parts by weight.

(Example 1) φ30 mm, length 254 mm
The aluminum cylinder of the support is used as a support, and a coating composed of the following materials is applied to the support by a dipping method at 140 ° C.
Heat curing was performed for 30 minutes to form a 15 μm conductive layer.

Conductive pigment: 10 parts of barium sulfate treated with SnO ₂ coating Pigment for resistance control: 2 parts of titanium oxide Binder resin: 6 parts of phenol resin Leveling material: 0.001 part of silicone oil Solvent: methanol / methoxypropanol (0.2 /0.8) 20 parts

Next, 3 parts of N-methoxydimethylated nylon and 3 parts of copolymerized nylon were placed on the conductive layer.
A solution dissolved in a mixed solvent of 5 parts / 30 parts of n-butanol was applied by a dipping method to form a 0.5 μm intermediate layer.

Next, in the X-ray diffraction of CuKα, the Bragg angles 2θ ± 0.2 degrees of 9.0 degrees, 14.2 degrees and 23.9 degrees were used.
Oxytitanium phthalocyanine (TiOPc), which has a strong peak at 27.1 degrees, 2 parts of polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) and 60 parts of cyclohexanone were sand-milled using φ1 mm glass beads. After dispersion for 4 hours, 100 parts of ethyl acetate was added to prepare a charge generation layer dispersion. This was applied by an immersion method to form a 0.3 μm charge generation layer.

Next, 9 parts of an amine compound having the following structural formula:

[0058]

Embedded image 1 part of amine compound of the following structural formula

[0059]

Embedded image And 10 parts of the resin described in Condition 1 of Table 5 were dissolved in a mixed solvent of 50 parts of monochlorobenzene / 50 parts of dichloromethane. The weight average molecular weight was a value in terms of polystyrene measured by GPC (gel permeation chromatography). This paint is applied by a dipping method,
After drying for 2 hours, a 25 μm charge transport layer was formed.

Next, the evaluation will be described. The device is a Hewlett-Packard LBP "Laser Jet 4plus" having a contact charging roller as a primary charging member.
(Process speed: 71 mm / sec) was modified and used. In the remodeling, the primary charging was changed from constant current control to constant voltage control (direct voltage: -700 V, peak-to-peak voltage of AC voltage: 1.6 KV, frequency: 1 kHz).

The prepared electrophotographic photosensitive member was subjected to 28
A paper passing durability test was performed at 90 ° C. and 90% RH. The image is A4
Thus, a grid pattern having a printing rate of 4% was obtained. The sequence was an intermittent mode in which the printing was stopped once for each print. When the toner ran out, the toner was replenished, the image was repeatedly printed until a problem occurred in the image, and the number of sheets when the problem occurred was recorded. The observation was made visually.

Next, at 33 ° C., 95
Paper with 10% moisture absorption (% Infrare
MOISTREX MX manufactured by d Engineering
(Measured using 5000), and 2,000 sheets of continuous paper endurance were used to evaluate the image deletion. The image is A4
As an E character pattern with a printing rate of 4%,
2,000 sheets, 2,000 sheets, E-character image left without standing for 24 hours after image endurance, when no image deletion occurs ○, when image deletion occurs but character can be discriminated, △, character is something The ones that could not be discriminated were evaluated as x, and the ones in which the characters had completely disappeared were evaluated as xx.

A 15-minute abrasion was performed using a Taber abrasion tester using a polishing tape, and the weight loss at that time was measured. Table 6 shows the results.

Examples 2 to 14 Condition Nos. In Table 5 were used as binders in the charge transport layer. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the resins described in Nos. 2 to 14 were used. Table 6 shows the results.

[0065]

[Table 4]

[0066]

[Table 5]

[0067]

[Table 6]

(Comparative Examples 1 to 3) Condition Nos. In Table 7 were added to the binder resin of the charge transport layer. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the resins described in 1 to 3 were used. Table 8 shows the results.

[0069]

[Table 7]

(Comparative Example 4) The binder resin of the charge transport layer was treated with the condition No. 6 parts of the resin described in 3 and the condition N
o. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 4 parts of the resin described in 4 were used. Table 8 shows the results.

(Comparative Example 5) The binder resin of the charge transport layer was charged with the condition No. 1 and 5 parts of the resin described in Table 4. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that 5 parts of the resin described in 5 were used. Table 8 shows the results.

(Comparative Example 6) Condition No. 4 shown in Table 4 was added to the binder resin of the charge transport layer. No. 12 and 8 parts of the resin described in Table 4 were used. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that two parts of the resin described in No. 13 were used. Table 8 shows the results.

[0073]

[Table 8]

[0074]

The electrophotographic photoreceptor of the present invention can provide an electrophotographic photoreceptor which maintains excellent mechanical strength, has good electric resistance due to charging, and also has a good image deletion evaluation. It has become possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member of the present invention.

Claims (6)

[Claims] 1. An electrophotographic photoreceptor having a conductive support and a photosensitive layer, and an electrophotographic photoreceptor which is disposed in contact with the electrophotographic photoreceptor and is applied with a voltage obtained by superimposing an AC voltage on a DC voltage. In an electrophotographic photoreceptor used in an electrophotographic apparatus having a charging member for charging an electrophotographic photoreceptor, the surface layer of the electrophotographic photoreceptor has a weight average molecular weight of 3.7 × 10 ⁴ or more, represented by the following formula (1): polyarylate resin having the unit, and having a weight average molecular weight of polyarylate resin or less than 3.7 × 10 ⁴ having a structural unit represented by the following formula (1) having a weight average molecular weight of less than 3.7 × 10 ⁴ At least one of polycarbonate resins
An electrophotographic photoreceptor comprising a seed. Embedded image (Wherein, X is -CR ₁₃ R ₁₄ - is a [where R ₁₃ and R ₁₄ are the same or different and each represents a hydrogen atom, a trifluoromethyl group, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, ], a substituted or unsubstituted cycloalkylidene group, a substituted or unsubstituted alpha, .omega. alkylene group, a single bond, -O -, - S -, - SO-, or -SO ₂ - is also R ₁ ~ R ₁₂ is the same or different and is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group) 2. A polyarylate resin having a structural unit represented by the formula (1) having a weight average molecular weight of 4.5 × 10 ^{4 to} 2.5 × 10 ⁵ and 7.5 × 10 ^{3 to} 3.0 × 10 ⁴
The polyarylate resin represented by the formula (1) having a weight average molecular weight of at least one of a polycarbonate resin having a weight average molecular weight of 7.5 × 10 ^{3 to} 3.0 × 10 ^4. Electrophotographic photoreceptor. 3. The polyarylate resin having a structural unit represented by the formula (1) having a weight average molecular weight of 3.7 × 10 ⁴ or more has a polydispersity of 4.0 or less.
The electrophotographic photosensitive member according to the above. Wherein the polyarylate resin or 3.7 × 10 polycarbonate resin having a weight average molecular weight of less than ⁴ having a structural unit represented by the formula (1) having a weight average molecular weight of less than 3.7 × 10 ⁴ dispersion The electrophotographic photoreceptor according to claim 1, wherein the degree is 3.0 or less. 5. An electrophotographic apparatus main body which integrally supports at least one means selected from the group consisting of the electrophotographic photosensitive member according to claim 1, a charging means, a developing means and a cleaning means. A process cartridge which is detachably mounted on a process cartridge. 6. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an image exposing unit, a developing unit, and a transferring unit.