JPH1039521A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an erectrophotographic photoreceptor having superior solvent cracking resistance without deteriorating mechanical strength and having satisfactory resistance to electricity by direct electrification and a less photometry by forming a surface layer contg. a polymer having specified constituent units. SOLUTION: The surface layer of this electrophotographic photoreceptor with a photosensitive layer on the electrically conductive substrate contains a polymer having constituent units represented by formula I or II. In the formulae I, II, each of R1 -R16 and R21 -R34 is H, halogen, optionally substd. alkyl, optionally substd. aryl or optionally substd. alkenyl, R25 and R26 may bond to each other to from divalent alkylidene, (n) is an integer of 0-7 and (m) is an integer of 2-4.

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, 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 The present invention relates to a process cartridge having an electrophotographic photosensitive member and an electrophotographic apparatus.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
As shown in JP-A No. 1 (1993), a photoconductive material comprising a support coated with an insulating substance is used in which the electric resistance changes in accordance with the amount of irradiation received during image exposure, and in a dark place. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material are (1) that it can be charged to an appropriate potential in a dark place, (2) that the potential is less dissipated in a dark place, and (3) And (3) quickly dissipating the charge by light irradiation.

[0003] Conventionally, selenium,
Inorganic photoreceptors having a photosensitive layer mainly containing an inorganic photoconductive compound such as zinc oxide and cadmium sulfide have been widely used. However, these satisfies the conditions (1) to (3), but are not necessarily satisfactory in thermal stability, moisture resistance, durability and productivity.

In order to overcome the disadvantages of inorganic photoconductors, electrophotographic photoconductors containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, US Pat.
No. 851 describes a photoreceptor having a charge transporting layer containing triallylpyrazolin, and US Pat. No. 3,871,880 discloses a photogenerating layer comprising a derivative of perylene pigment and 3
Photoreceptors comprising a charge transport layer comprising a condensate of propylene and formaldehyde are known.

Further, the organic photoconductive compound can freely select the photosensitive wavelength range of the electrophotographic photosensitive member depending on the compound.
JP-A Nos. 2754 and 56-167759 disclose substances exhibiting high sensitivity in the visible region, and JP-A-57-19576 and JP-A-61-22.
No. 8453 discloses a compound having sensitivity up to the infrared region.

[0006] Of these materials, those exhibiting sensitivity in the infrared region are used in laser beam printers (hereinafter abbreviated as LBPs) and LED printers, which have been remarkably advanced in recent years, and the demand frequency thereof is increasing.

Electrophotographic photoreceptors using these organic photoconductive compounds are used as function-separated type photoreceptors in which a charge transport layer and a charge generation layer are laminated in order to satisfy both electrical and mechanical properties. In many cases. On the other hand, it is needless to say that the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and even optical characteristics according to the electrophotographic process applied.

Particularly, in the case of an electrophotographic photoreceptor that is used repeatedly, an external electric or mechanical force such as corona or direct charging, image exposure, toner development, transfer step and surface cleaning is directly applied to the electrophotographic photoreceptor surface. For,
Durability against them is also required.

Specifically, electrical deterioration due to ozone and nitrogen oxides during charging, mechanical deterioration in which the surface is worn or scratched due to discharge during charging, and rubbing of the cleaning member, and electrical deterioration Durability is required.

[0010] The electrical deterioration is particularly problematic in that carriers stay in a portion irradiated with light and a potential difference is generated between the portion not irradiated with light and a photo memory.

[0011] Unlike an inorganic photoreceptor, an organic photoreceptor, which is often soft in material, is inferior in durability against mechanical deterioration and is particularly demanded to improve durability.

Various attempts have been made to satisfy the durability characteristics required for the photoreceptor as described above.

As a resin often used for the surface layer and having good abrasion and electric properties, a polycarbonate resin having bisphenol A as a skeleton has been attracting attention. However, not all of the above-mentioned problems can be solved, and the following problems cannot be solved. It has such problems.

(1) It has poor solubility and shows good solubility only in a part of halogenated aliphatic hydrocarbons such as dichloromethane and 1,2-dichloroethane. In addition, since these solvents have a low boiling point, they have low solubility. When a photoreceptor is manufactured using a coating solution prepared with the above solvent, the coated surface is likely to be whitened. It also takes time to control the solid content of the coating liquid.

(2) Solvents other than halogenated aliphatic hydrocarbons are partially soluble in tetrahydrafuran, dioxane, cyclohexanone or a mixed solvent thereof, but the solution gels in a few days. Inferior aging,
It is not suitable for photoconductor production.

(3) Further, even if the above formulas (1) and (2) are improved, solvent cracks are liable to occur in the polycarbonate resin having bisphenol A as a skeleton.

(4) In addition, in the case of a conventional polycarbonate resin, the coating formed of the resin does not have lubricity, so that the photosensitive member is easily damaged, and the cleaning setting for reducing the abrasion amount of the electrophotographic photosensitive member is not sufficient. In some cases, an image defect such as toner fusion occurs, or cleaning failure occurs due to early deterioration of the cleaning blade.

For the solution stability mentioned in the above (1) and (2), use of a polycarbonate Z resin having a bulky cyclohexylene group as a structural unit of the polymer, or copolymerization with bisphenol Z or bisphenol C, etc. Has been solved by

Solvent cracks can also be solved by using a silicone-modified polycarbonate or an ether-modified polycarbonate, as disclosed in JP-A-6-51544 and JP-A-6-75415. . However, compared to conventional polycarbonate resins, these modified polycarbonates have a structure that has flexibility against internal stress in the polymer in order to prevent solvent cracks, and as a result, the mechanical There was a disadvantage that the strength was reduced.

Further, in recent years, a direct charging system disclosed in JP-A-57-17826 and JP-A-58-40566, in which a voltage is applied directly to a charging member and a charge is applied to an electrophotographic photosensitive member. Is becoming mainstream.

This is a method in which a roller-shaped charging member made of a conductive rubber or the like is brought into direct contact with an electrophotographic photosensitive member to apply an electric charge. The scorotron generates a significantly smaller amount of ozone than a scorotron or the like. While about 80% of the current flowing through the charger flows through the shield, it is wasted, whereas direct charging has the advantage that it is very economical without this waste.

However, direct charging has a disadvantage that charging stability is very poor because of charging by discharge according to Paschen's rule. As a countermeasure, a so-called AC / DC charging method in which an AC voltage is superimposed on a DC voltage has been devised (Japanese Patent Application Laid-Open No. 63-149668).

Although this charging method has improved the stability during charging, the amount of discharge on the surface of the electrophotographic photosensitive member is greatly increased due to the superposition of AC, so that the amount of scraping of the electrophotographic photosensitive member increases. A new drawback has arisen, requiring not only mechanical strength but also electrical strength.

[0024]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of having a conventional polycarbonate resin as a surface layer, to have excellent solvent crack resistance without impairing mechanical strength, and An object of the present invention is to provide an electrophotographic photoreceptor which has good electric resistance due to direct charging, has less photo memory, is easy to manufacture, and a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor.

[0025]

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member has the following formula (1) or (3):
An electrophotographic photoreceptor comprising a polymer having a structural unit represented by the formula:

[0026]

Embedded image (Wherein, R _{1 to} R _{16 each} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkenyl group which may be substituted, and n represents an integer of 0 to 7)

[0027]

Embedded image (Wherein, R _{21 to} R _{34 each} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkenyl group which may be substituted. R ₂₅ and R ₂₆ are bonded to each other to form a divalent alkylidene group M is an integer of 2 to 4.)

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the above formulas (1) and (3), halogen atoms include fluorine, chlorine and bromine atoms, and alkyl groups include methyl, ethyl and propyl groups. Alkenyl groups include vinyl, propenyl and butenyl groups, and aryl groups include phenyl, naphthyl and anthryl groups, and alkylidene groups include ethylidene, propylidene and i-butylidene groups. And the substituents that these may have include the above-described halogen atoms, alkyl groups, and aryl groups.

Specific examples of the structural units represented by the above formulas (1) and (3) are shown in Tables 1 and 2, but are not limited thereto.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

Preferred examples of the structural unit represented by the formula (1) include structural unit examples 1-1, 1-2, 1-5, 1-8 and 1-13, and in particular, structural unit example 1-1. , 1-5
And 1-8 are preferred.

Preferred examples of the structural unit represented by the formula (3) include structural unit examples 2-1, 2-2, 2-6 and 2-8
Is mentioned.

Formula (1) used in the present invention,
The polymer having the structural unit represented by (3) is prepared by mixing a bisphenol represented by the following formulas (4) and (5) with a mixture of terephthalic acid chloride and isophthalic acid chloride under an alkali in order to increase the solubility. It can be synthesized by performing interfacial polymerization by stirring in a solvent / water system.

[0036]

Embedded image (Wherein, R _{1 to} R _{12 each} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkenyl group which may be substituted, and n represents an integer of 0 to 7)

[0037]

Embedded image (Wherein, R _{21 to} R _{30 each} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkenyl group which may be substituted. R ₂₅ and R ₂₆ are bonded to each other to form a divalent alkylidene group M is an integer of 2 to 4.)

In the electrophotographic photoreceptor of the present invention, a polymer composed of one kind of the structural unit represented by the formula (1) or (3) is also used as a polymer composed of two or more kinds of the formula (1) or (3). Copolymers consisting of units can also be used.

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, any chloride is 30 mol
Care must be taken when the content is less than 10% because the solubility of the synthesized polymer is extremely reduced. Usually, it is preferable to synthesize at a ratio of 1/1.

Further, a copolymer with other general bisphenols such as bisphenol Z, bisphenol A, bisphenol C and bisphenol AF may be prepared in consideration of solubility during polymerization. However, in this case, the structural unit represented by the formula (1) or (3) is 5 to 90% of the whole polymer.
mol%, preferably 10 to 10 mol%.
50 mol%.

The electrophotographic photoreceptor of the present invention containing a polymer having the structural units represented by the formulas (1) and (3) is particularly suitable for solvent crack resistance, mechanical strength, and electric resistance in AC charging. It has good electrophotographic characteristics.

The polymer having the structural units represented by the formulas (1) and (3) contains a unit having rigidity in the structural units, and the units are partially vitrified during the formation of the electrophotographic photosensitive member. Thereby, the durability of the entire polymer film is increased.

In addition, since the intramolecular density is increased by the partial vitrification inside the molecule and the amorphous portion and the crystalline portion are combined in the same molecule, the intramolecular stress generated at the time of forming the coating film can be reduced. It is presumed that even if a chemical causing a solvent crack enters, the internal stress is maintained and no crack occurs.

It is presumed that the mechanical strength is enhanced by the presence of the amorphous portion.

With respect to the electric resistance, the molecular cleavage due to electrical degradation is such that the active proton is not present in the central skeleton, and the arylate structure, which is an ester bond of an aryl group as compared with a carbonate bond, is strongly resistant to current caused by AC charging. It is considered that the electric resistance was 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.

In the case of the formula (1), in terms of one structure, it is easier to improve the strength as the number of central arylene groups increases, and it is preferable that n is larger. That is, when n is 1 to 7, the strength is better, and in consideration of solubility, n is more preferably 1 to 4. When n is 0, the configuration represented by the equation (1) is weakest in terms of strength, but the configuration represented by the equation (2) is specifically strong.

Hereinafter, the structure of the electrophotographic photosensitive member used in the present invention will be described.

The electrophotographic photoreceptor of the present invention may be either a single-layer type in which the photosensitive layer contains a charge transporting material and a charge generating material in the same layer, or a multilayer type in which the charge transporting layer and the charge generating layer are separated. Although good, the laminated type is preferable in terms of electrophotographic characteristics.

The conductive substrate to be used may be any one having conductivity, such as metal such as aluminum and stainless steel, or metal provided with a conductive layer, paper and plastic. Is mentioned.

When an image input such as LBP is a laser beam, 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 is preferable, and more preferably 10-30 μm
It is.

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

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, dibenzapyrene quinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine pigments. Can be In the case of the function separation type, the charge generation layer is obtained by mixing the charge generation material with a binder resin and a solvent in an amount of 0.3 to 4 times the amount of a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, a roll mill and a liquid collision type Disperse well by a method such as a high-speed disperser, apply the dispersion,
It is formed by drying. The thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.

The charge transport layer is formed by applying and drying a coating material in which a charge transport material and a binder resin containing a polymer used in the present invention 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 are combined with 0.5 to 2 times the amount of the binder resin, applied and dried to form a charge transport layer. The thickness of the charge transport layer is preferably from 5 to 40 μm, more preferably from 15 to 30 μm.

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 a shaft 2 at a predetermined peripheral speed in a direction indicated by an arrow. The photoreceptor 1 rotates during the rotation process.
The peripheral surface is uniformly charged with a predetermined positive or negative potential by the primary charging means 3, and then receives image exposure light 4 from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.

The formed electrostatic latent image is then developed by 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 surface of the photoreceptor, introduced into the image fixing means 8 and subjected to image fixing to be printed out as a copy out of the apparatus.

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

In the present invention, of the above-mentioned components such as the electrophotographic photosensitive member 1, the primary charging means 3, the developing means 5 and the cleaning means 9, a plurality of components are integrally connected as a process cartridge. This 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 copier or a printer, the image exposure light 4 is read and transmitted from the original, or the original is read by a sensor and converted into a signal, and the exposure is performed according to the signal. Laser beam scanning,
Light emitted by driving the LED array, driving the liquid crystal shutter array, and the like.

On the other hand, when used as a facsimile printer, the image exposure light 4 becomes exposure light for printing received data. FIG. 2 is a block diagram showing an example of this case.

The controller 14 controls the image reading section 13 and the printer 22. The entire controller 14 is controlled by the CPU 20. The read data from the image reading unit 13 is transmitted to the partner station through the transmission circuit 16. Data received from the partner station is sent to the printer 22 through the receiving circuit 15. Predetermined image data is stored in the image memory. The printer controller 21 controls the printer 22. 17 is a telephone.

An image received from the line 18 (image information from a remote terminal connected via the line) is demodulated by the receiving circuit 15 and then decoded by the CPU 20 to be sequentially stored in the image memory 19. Is done. When the image of at least one page is stored in the memory 19, the CPU 20 performs image recording of the page. The CPU 20 reads out the image information of one page from the image memory 19, and Sends out image information. The printer controller 21
When receiving one page of image information from the CPU 20, the printer 22 is controlled to record image information of the page. The CPU 20 is receiving the next page during recording by the printer 22.

Thus, the reception and recording of the image are performed.

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.

The following is a description of the embodiment. The middle part in the examples indicates parts by weight.

Example 1 An aluminum cylinder having a diameter of 30 mm and 254 mm was used as a support, and a coating composed of the following materials was applied on the support by a dip coating method, and was thermally cured at 140 ° C. for 30 minutes to obtain a 15 μm Was formed.

Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: titanium oxide 2 parts Binder resin: phenol resin 6 parts Leveling material: silicone oil 0.001 parts Solvent: methanol, methoxypropanol 0.2 / 0.8 20 parts

Next, a solution obtained by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol was applied thereon by dip coating to form a coating having a thickness of 0.5 μm. Was formed.

Next, oxytitanium phthalocyanine (TiOPc) having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° in Bragg angles 2θ ± 0.2 ° of CuKα characteristic X-ray diffraction. ) 4 parts of polyvinyl butyral (trade name: Esrec BM2, manufactured by Sekisui Chemical) and 60 parts of cyclohexanone were dispersed for 4 hours by a sand mill using φ1 mm glass beads for 4 hours, and then 100 parts of ethyl acetate was added to form a charge generating layer. A dispersion was prepared.
This was applied by a dip coating method to form a 0.3 μm charge generation layer.

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

[0073]

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

[0074]

Embedded image And Example No. 3 in Table 3. 10 parts of the polymer shown in 1 were dissolved in a mixed solvent of 30 parts of monochlorobenzene and 70 parts of dichloromethane.

This polymer is prepared from a predetermined biphenol (0.01
mol) was dissolved in sodium hydroxide (0.8 g), tetramethylammonium chloride (1 g) and 100 ml of water, and charged into a 1-liter mixer, into which terephthalic acid chloride (1,2-dichloroethane (30 ml)) was added. 0.0
05mol) and isophthalic acid chloride (0.005mo)
l) was added while stirring, and the mixture was stirred at a high speed for 10 minutes and allowed to stand for 2 hours. Then, a 1,2-dichloroethane solution was collected, and a large amount of hexane was added thereto to collect as a polymer. Note that, after recovery, a product that had been subjected to a purification step by washing with water, dissolving in chloroform, and adding methanol dropwise was used.

This paint is applied by a dip coating method,
It was dried at 120 ° C. for 2 hours to form a 25 μm charge transport layer.

Next, evaluation will be described.

The device is a Hewlett-Packard LBP
"Laser jet 4plus" (process speed 7
1 mm / sec). In the remodeling, primary charging was controlled by constant current control and constant voltage control. The produced electrophotographic photosensitive member was subjected to paper passing durability (HH durability) at 28 ° C. and 90% RH using this apparatus. The sequence was an intermittent mode in which the print was stopped once for each print.

When the toner ran out, the toner was replenished and the image was durable until a problem occurred in the image. Further, abrasion was performed for 15 minutes using a Taber abrasion tester using a polishing tape, and the weight loss at that time was measured.

Further, 3000 L of a part of the electrophotographic photosensitive member is used.
ux, the light of a white fluorescent lamp was applied for 10 minutes, and after standing for 10 minutes, the bright portion potential was measured, and how much the bright portion potential decreased before the application of the light was measured to obtain a photo memory value.

Further, regarding the solvent cracking property, sebum was adhered to the surface and allowed to stand for 48 hours, and the presence or absence of a solvent crack was observed by microscopic observation.

Table 4 shows the results.

[0083]

[Table 4] The mixing ratio between terephthalic acid chloride and isophthalic acid chloride was 1: 1 in molar ratio. Example 6 used 1,4 dimethyl terephthalic acid chloride instead of terephthalic acid chloride.
The molecular weight was measured by gel permeation chromatography.

[Examples 2 to 12] In Example 3 of Table 3, the binder resin of the charge transport layer was used. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that those having 2 to 12 were used. Table 4 shows the results.

[0085]

[Table 5]

[Comparative Examples 1 to 5] An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder resin for the charge transport layer used was one of the conditions 1 to 5 shown in Table 5. Table 6 shows the results.

[0087]

[Table 6]

[0088]

[Table 7]

Example 13 An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the following polymer was used as the binder resin of the charge transport layer, and the measurement conditions of the photo memory were further changed. Table 8 shows the results.

The polymer used in this example is a structural unit example 2
-1 required to make biphenol (0.003m
ol) and bisphenol Z are converted to sodium hydroxide (0.
8g), tetramethylammonium chloride (1g) and water 1
The mixture was poured into a 1 liter mixer, and a mixture of terephthalic acid chloride (0.005 mol) and isophthalic acid chloride (0.005 mol) in 1,2-dichloroethane (30 ml) was stirred. The mixture was charged, stirred at a high speed for 10 minutes, and allowed to stand for 2 hours. Then, a 1,2-dichloroethane solution was recovered, and a large amount of hexane was charged into the solution to recover as a polymer. Note that, after recovery, a product that had been subjected to a purification step by washing with water, dissolving in chloroform, and adding methanol dropwise was used. The final yield was 51%.

However, the photo memory value was as follows: a portion of the electrophotographic photosensitive member was exposed to light of a white fluorescent lamp at 3000 Lux for 20 minutes and left for 4 minutes, and then the bright portion potential was measured. It was measured by how much it fell.

As a ghost evaluation method, a ghost evaluation pattern was circulated on the image once around the drum, and then switched to a halftone image, and it was visually determined whether or not ghost occurred on the halftone image.

[0093]

[Table 8] The mixing ratio between terephthalic acid chloride and isophthalic acid chloride was 1: 1 in molar ratio. The molecular weight was measured by gel permeation chromatography.

[Examples 14 to 22] The binders of Example Nos. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 13 except that those of Nos. 14 to 22 were used. Table 8 shows the results.

[0095]

[Table 9]

[Comparative Examples 6 to 9] The same procedures as in Example 13 were carried out except that the binder of the charge transport layer used was one of the conditions 1 to 4 in Table 9.
An electrophotographic photoreceptor was prepared and evaluated in the same manner as described above. Table 10 shows the results.

[0097]

[Table 10]

[0098]

[Table 11]

[0099]

The electrophotographic photoreceptor of the present invention has excellent solvent crack resistance without impairing the mechanical strength, has high mechanical strength, and has good electric resistance against discharge due to direct charging. It has become possible to provide an electrophotographic photosensitive member suitable for direct charging, which has less photo memory and is easy to manufacture, and a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

[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.

FIG. 2 is a diagram illustrating an example of a block diagram of a facsimile having the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor of this invention 2 axis 3 Primary charging means 4 Image exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Image fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail 13 Image reading section 14 Controller 15 Receiving circuit 16 transmitting circuit 17 telephone 18 line 19 image memory 20 CPU 21 printer controller 22 printer

Claims (7)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member contains a polymer having a structural unit represented by the following formula (1). An electrophotographic photosensitive member characterized by the following. Embedded image (Wherein, R _{1 to} R _{16 each} represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkenyl group which may be substituted, and n represents an integer of 0 to 7) 2. The electrophotographic photosensitive member according to claim 1, wherein n in the formula (1) is 1 to 7. 3. The electrophotographic photosensitive member according to claim 1, wherein n in the formula (1) is 0. 4. The electrophotographic photoconductor according to claim 1, wherein the structural unit represented by the formula (1) is a structural unit represented by the following formula (2). Embedded image (Wherein R _{13 to} R ₁₆ are the same as those in the above formula (1), and R ₁₇ and R ₁₈ represent a hydrogen atom or a methyl group.
_At least one of ₁₇ and R ₁₈ is a methyl group. ) 5. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the surface layer of the electrophotographic photosensitive member contains a polymer having a structural unit represented by the following formula (3). An electrophotographic photosensitive member characterized by the following. Embedded image (Wherein, R _{21 to} R ₃₄ represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkenyl group which may be substituted. R ₂₅ and R ₂₆ are bonded to each other to form a divalent alkylidene group. M is an integer of 2 to 4.) 6. The electrophotographic photoreceptor according to claim 1, wherein:
A process cartridge which integrally supports at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit, and is detachable from an electrophotographic apparatus main body. 7. The electrophotographic photoreceptor according to claim 1, wherein
An electrophotographic apparatus comprising a charging unit, an image exposing unit, a developing unit, and a transferring unit.