JPH11184114A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus having this photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the electrophotographic photoreceptor high in sensitivity characteristics in a long wavelength region suitable for a light printer and small in potential fluctuation at the time of repeated uses. SOLUTION: Relating to this photoreceptor with a photosensitive layer formed on a conductive substrate, the photosensitive layer contains a bisazo pigment having intense peaks at Bragg angle (2θ±0.2 deg.) of 5.2 deg. and 26.8 deg. in the X-ray- diffraction using Cu-Kα line and its half value width of 0.63 and 0.94 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-layer type electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide, and zinc oxide have been widely used in electrophotographic photoreceptors.

On the other hand, as an electrophotographic photoreceptor using an organic photoconductive substance, a photoconductive polymer represented by poly-N-vinyl carbazole or 2,5-bis- (p-diethylaminophenyl) Known are those using a low molecular weight photoconductive substance such as -1,3,4-oxadiazole, and those combining such an organic photoconductive substance with various dyes and pigments. .

An electrophotographic photoreceptor using an organic photoconductive substance has good film forming properties and can be produced by coating, and thus has the advantage of providing a photoreceptor with extremely high productivity and low cost. In addition, there is an advantage that the emotional color can be freely controlled by selecting a dye or a pigment to be used, and wide studies have been made so far. After that, by developing a function-separated type photoreceptor in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material were laminated, sensitivity and durability, which were disadvantages of conventional organic photoreceptors, were improved. Significant improvements have been made and are now widely used.

The charge-generating substance affects the photosensitive wavelength range of the photoreceptor. With the spread of laser beam printers and LED printers in recent years, the oscillation wavelength range of such a light source is 66.
It has been desired to develop a charge generating material that exhibits high sensitivity from 0 nm to 800 nm and at the same time has good potential stability when used repeatedly for photoreceptors.

The benzanthrone-based bisazo pigment has excellent sensitivity characteristics even in the long wavelength region as described above, and is an excellent charge generating substance capable of providing an electrophotographic photosensitive member having good potential stability upon repeated use. However, the recent demand for higher speed and higher image quality of the printer has not always been satisfactory particularly in terms of sensitivity.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photosensitive member having high sensitivity characteristics in a long wavelength region suitable for an optical printer as described above, and having a small potential fluctuation when repeatedly used. To provide. Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus using the electrophotographic photosensitive member.

[0008]

The present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer has a Bragg angle of 2 in X-ray diffraction by Cu-Kα ray.
θ of 5.1 ° (± 0.2 °) and 26.8 ° (± 0.2 °)
(°) and a bisazo pigment represented by the following general formula (1) having a peak half width of 0.7 ° or less and 1.0 ° or less, respectively. It is composed of a characteristic electrophotographic photoreceptor. General formula (1)

Embedded image In the formula, R represents a methyl group or an ethyl group.

According to the present invention, there is further provided an electrophotographic photoreceptor of the present invention, and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means, integrally supported on the electrophotographic apparatus main body. It is composed of a process cartridge characterized by being detachable.

Further, the present invention comprises an electrophotographic apparatus comprising the electrophotographic photosensitive member of the present invention, a charging unit, an image exposing unit, a developing unit and a transfer unit.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The bisazo pigment represented by the general formula (1) is obtained by tetrazotizing diaminobenzanthrone by a conventional method, and once isolating it in the form of a borofluoride salt.
In a solvent such as N, N-dimethylformamide, in the presence of a base, a coupler represented by the general formula (2)

Embedded image (Wherein, R represents a methyl group or an ethyl group).

As shown in FIG. 5 (R: ethyl group) and FIG. 6 (R: methyl group), the crystal state after the synthesis is 5.5 °.
And a peak was observed at around 26.7 °, but it was a brode and the crystallinity was not very good.

However, by subjecting this to heat treatment in a solvent, the crystallinity can be increased, and an electrophotographic photoreceptor using a pigment having such increased crystallinity can use a conventional low-crystalline pigment. The present inventors have found that the sensitivity is greatly improved as compared with the case where it is used, and have reached the present invention. With the improvement in crystallinity, the half widths of the peaks at 5.5 ° and 26.7 ° are reduced, and at the same time, the position of the peak at 5.5 ° is 5.1 °.
Shift to

The crystallinity is compared by the peak half width in the X-ray diffraction diagram. The peak half widths around 5.1 ° and 26.7 ° are 0.7 ° or less and 1.0%, respectively. ° or less, preferably 0.6 ° or less, and those having improved crystallinity until 0.8 ° or less are good.

The solvent used in the solvent treatment is not particularly limited, but it is preferable to use a solvent having good wettability with the pigment and having a high boiling point, since the solvent can be brought to a predetermined crystallinity in a short time. Examples of such a solvent include 1,4-dioxane, cyclohexanone, N, M-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide and the like.

Generally, whether the crystalline state of the charge generating substance is crystalline or amorphous is different depending on each material, and the phthalocyanine compound is generally different from the crystalline state. Many are highly sensitive,
Among the azo pigments, there are compounds having higher crystallinity and higher sensitivity, such as compounds described in JP-B-6-97344, and compounds such as compounds described in JP-B-7-117760. In some cases, the sensitivity becomes better when the material is made amorphous, and it differs depending on each material.

Next, a production example of the bisazo pigment represented by the general formula (1) will be described.

Production Example 1 Synthesis of bisazo pigment having the following structural formula

Embedded image 500 ml of DMF is placed in a 1 liter beaker, and a coupler of the following structural formula is added.

Embedded image After dissolving 3.0 g (7.23 mmol) of the solution and cooling the solution to 0 ° C., a tetrazonium salt of the following structural formula was synthesized in advance by a conventional method.

Embedded image 1.6 g (3.44 mmol) are dissolved and then N-
0.9 g of methyl formalin was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration. Then 500
The mixture was stirred and washed four times with 2 ml of DMF at room temperature for 2 hours, replaced with water, and lyophilized. 90% yield.

FIG. 5 shows an X-ray diffraction pattern of the obtained bisazo pigment.
Shown in The half width of the peak at 5.4 ° is 0.83 °, 2
The FWHM of the peak at 6.7 ° was 1.25 °. This is designated as Comparative Sample 1.

Next, 1.0 g of the above pigment was added to 80 ml of DMF.
Inside, treated under the conditions shown in Table 1 below, filtered, washed with water,
Lyophilized. Table 1 shows the half width of each peak of the obtained crystal.
Shown in

[0021]

[Table 1]

Production Example 2 Synthesis of bisazo pigment having the following structural formula

Embedded image A compound represented by the following structural formula

Embedded image A bisazo pigment was synthesized in exactly the same manner as in Production Example 1 except that the above was used. The X-ray diffraction diagram is shown in FIG. 5.5 ° peak
The half value width of the peak was 0.83 °, and the half value width of the peak at 26.7 ° was 1.39 °. This is designated as Comparative Sample 2.

Next, 1.0 g of the above pigment was added to 80 ml of DMF.
In a heat treatment at 150 ° C. for 20 minutes in a filter, filtered, washed with water and freeze-dried. FIG. 6 shows an X-ray diffraction pattern of the obtained crystal.
The half value width of the peak at 5.1 ° was 0.31 °, and the half value width of the peak at 26.9 ° was 0.42 °. This is designated as Sample 2.

The X-ray diffraction measurement was performed under the following conditions. Measuring machine used: X-ray diffractometer MX manufactured by Mac Science
P ¹⁸ X-ray tube: Cu, tube voltage: 50.0 kV, tube current: 25
0.0 mA, scan method: 2θ / θ scan, scan speed: 4.0 deg. / Min, sampling width:
0.02 deg. Start angle: 3.0 deg. , Stop angle: 35.0 deg. Divergent slit: 0.5
0 deg. , Scattering slit: 0.50 deg. , Light receiving slit: 0.30 mm, using monochrome meter.

As shown in FIG. 5, the half-width value of the peak is 1 / H of the height of the peak from the base line.
2 represents the width of the peak at a height of 2.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing a bisazo pigment represented by the general formula (1) on a conductive support. The form of the photosensitive layer may be any known form, but a layer containing a bisazo pigment represented by the general formula (1) is used as a charge generation layer, and a charge transport layer containing a charge transport substance is laminated on this. A function-separated type photosensitive layer is particularly preferred.

The charge generation layer can be formed by applying a coating solution obtained by dispersing the above specific bisazo pigment in a suitable solvent together with a binder resin on a conductive support by a known method. It is desirable that the film thickness be 5 μm or less, preferably 0.1 to 1 μm.

Further, if necessary, it can be used in combination with a known charge generating substance other than the bisazo pigment.

The binder resin is selected from a wide range of insulating resins or organic photoconductive polymers, but includes polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, and the like. Phenoxy resins, cellulose resins, acrylic resins, resins which may have a substituent in the resin constitutional unit such as polyurethane and the like are preferable. Examples of the substituent include a halogen atom such as a fluorine atom and a bromine atom, methyl, ethyl and propyl. Alkyl groups such as acetyl and benzyl, alkylamino groups such as dimethylamino, and haloalkyl groups such as phenylcarbamoyl group, nitro group, cyano group and trifluoromethyl group. The amount of the binder resin used is 80% by weight or less, preferably 40% by weight or less in terms of the content in the charge generation layer.

The solvent is preferably selected from those which dissolve the binder resin and do not dissolve the charge transport layer and the undercoat layer described below. For example, ether compounds such as tetrahydrofuran (THF) and 1,4-dioxane, cyclohexanone, methyl ethyl ketone (MEK)
Such as ketone compounds such as N, N-dimethylformamide (DMF), ester compounds such as methyl acetate and ethyl acetate, aromatic compounds such as toluene, xylene and monochlorobenzene, methanol and ethanol.
And alcohol-based compounds such as chloroform and methylene chloride, and the like.

The charge transport layer is stacked on or below the charge generation layer, and has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transport layer is formed by applying a coating solution in which a charge transport material is dissolved in a solvent together with an appropriate binder resin as required. Its film thickness is 5 to 40 μm, preferably 15 to
30 μm.

The charge transporting substance includes an electron transporting substance and a hole transporting substance. As the electron transporting substance, for example,
Examples thereof include electron-withdrawing substances such as 4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, and tetracyanoquinodimethane, and those obtained by polymerizing these electron-withdrawing substances.

Examples of the hole-transporting substance include polycyclic aromatic compounds such as pyrene and anthracene, carbazole, and
, Imidazole, oxazole, thiazole, oxadiazol, pyrazol, pyrazoline, thiadiazo-
A heterocyclic compound such as p-diethylaminobenzaldehyde-N, N-diphenylhydrazone;
N, N-diphenylhydrazino-3-methylidene-9-
Hydrazone compounds such as ethyl carbazole, α-phenyl-4′-N, N-diphenylaminostilbene, 5
-[4- (di-p-tolylamino) benzylidene] -5
Styryl compounds such as H-dibenzo [a, d] cycloheptene, benzidine compounds, triarylmethane compounds, triarylamine compounds, triphenylamine, or polymers having a group consisting of these compounds in the main chain or side chain -(For example, poly-N-vinylcarbazo-
, Polyvinyl anthracene, etc.).

In addition to these organic charge transport materials, inorganic compounds such as selenium, selenium-tellurium, amorphous silicon and cadmium sulfide can also be used.

The charge transport materials can be used alone or in combination of two or more. When the charge transport material does not have a film-forming property, an appropriate binder resin can be used, and an acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polysulfone, or polysulfone can be used. Examples thereof include insulating resins such as acrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinyl carbazole and polyvinyl anthracene.

Examples of the conductive support on which the photosensitive layer is formed include aluminum, aluminum alloy, copper, zinc, stainless steel, titanium, nickel, indium, gold, platinum and the like. Also, plastics (for example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) and conductive particles (for example, carbon black, silver particles, etc.) formed by coating such metals or alloys by vacuum evaporation. With a suitable binder, or a support in which conductive particles are impregnated into plastic or paper.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer.
The thickness of the undercoat layer is 5 μm or less, preferably 0.1 to 3 μm.
m. The undercoat layer is made of casein or polyvinyl alcohol.
Nitrocellulose, polyamide (nylon 6, Naolone 66, nylon 610, copolymer nylon, N-alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, and the like.

Another specific example of the electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which the specific bisazo pigment and a charge transport material are contained in the same layer. At this time, a charge transfer complex composed of poly-N-vinylcarbazole and trinitrofluorenone can be used as the charge transport material. The electrophotographic photoreceptor of this example can be prepared by applying and drying a liquid in which the above specific bisazo pigment and a charge transport material are dispersed in an appropriate resin solution.

Further, a thin protective layer may be provided on the surface of the photosensitive layer in order to protect the photosensitive layer from external impact.

The electrophotographic photoreceptor of the present invention has a laser beam
Printer, CRT printer, LED printer,
The present invention can be widely applied to not only printers such as liquid crystal printers but also ordinary electrophotographic copying machines and other electrophotographic application fields.

Next, the process cartridge and the electrophotographic apparatus of the present invention will be described. FIG. 8 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum-shaped electrophotographic photoreceptor of the present invention, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow around a flick 2. In the rotation process, the photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on the peripheral surface thereof by the primary charging means 3, and then the image exposure means (such as a slit exposure or a laser beam scanning exposure) is used. Shown)
Receives image exposure light 4 from. 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
Is transferred to the transfer material 6 from the paper supply unit (not shown) and fed between the photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the photosensitive member 1. Are sequentially transferred by the transfer means 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 fixing, thereby being printed out as a copy (copy) outside the apparatus. The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the transfer residual toner by the cleaning means 9, and further subjected to a static elimination process by the pre-exposure light 10 from the pre-exposure means (not shown). After that, it is repeatedly used for image formation. When the primary charging means 3 is a contact charging means using a charging roller or the like, pre-exposure is not necessarily required.

In the present invention, of the above-mentioned components such as the photoreceptor 1, primary charging means 3, developing means 5 and cleaning means 9, a plurality of components are integrally connected as a process cartridge. Alternatively, 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 means 3, the developing means 5 and the cleaning means 9 is integrally supported together with the photoreceptor 1 to form a cartridge, and the apparatus main body is guided by a guide means such as the rail 12 of the apparatus main body. The process cartridge 11 can be detachably mounted on the cartridge. When the electrophotographic apparatus is a copier or a printer, the image exposure light 4 uses reflected light or transmitted light from the original, or reads the original with a sensor and converts it into a signal. This is light emitted by scanning of the laser beam, driving of the LED array, driving of the liquid crystal shutter array, and the like.

[0044]

EXAMPLES Examples 1 to 5, Comparative Examples 1 and 250 5 g of methoxymethylated nylon (average molecular weight: 32,000) and 10 g of alcohol-soluble copolymerized nylon (average molecular weight: 29000) were placed on a 50 μm aluminum sheet in methanol.
A solution dissolved in 95 g of a metal layer was applied with a Myr bar to form an undercoat layer having a thickness of 0.6 μm after drying.

Next, 0.4 g of the bisazo pigment 1-1 prepared in Production Example 1, 8.6 g of tetrahydrofuran, and 15 ml of a glass bead having a diameter of 1 mm were placed in a 50 ml glass bottle and dispersed in a paint shaker for 5 hours. did. Next, 2.0 g of a 10% solution of polyvinyl benzal (degree of benzalization: 80 mol%) in tetrahydrofuran was added, and the mixture was further dispersed for 2 hours. The prepared coating solution was applied to the undercoat layer with a Myer bar to form a charge generation layer having a thickness of 0.2 μm after drying.

Next, a charge transport material having the following structural formula

Embedded image 5 g and polycarbonate (average molecular weight 40000) 5 g
Was dissolved in 35 g of monochlorobenzene, and a coating solution prepared by applying a Myer bar onto the charge generating layer was applied to form a charge transporting layer having a thickness of 21 μm after drying to prepare an electrophotographic photoreceptor.

Samples 1-2 to 1-4 of the bisazo pigment produced in Production Example 1 and Sample 2 produced in Production Example 2
And an electrophotographic photoreceptor was prepared under exactly the same conditions as above.

These photosensitive members were wound around an aluminum cylinder for a laser beam printer (trade name: LBP-SX, manufactured by Canon Inc.), and charged so that the dark area potential became -700 V. This was irradiated with laser light of 802 nm, and the amount of light required to lower the potential of -700 V to -200 V was measured to determine the sensitivity.

Next, these photoconductors are set to a dark area potential (V _D ).
Is set to −700 V and the bright portion potential (V _L ) is set to −200 V. Then, the air durability is continuously performed 4000 times, and the potentials of the dark portion and the bright portion after the durability are measured, and the difference from the initial potential is determined. The amount of change in the obtained potential (ΔV _D , ΔV _L ) was measured.

Table 2 shows the above results. Note that a negative sign in the amount of potential fluctuation indicates a decrease in the potential, and a positive sign indicates an increase in the potential.

[Table 2]

As can be seen from the results, Examples 1 to 5
The photoreceptor using a bisazo pigment with increased crystallinity, which is used in (1), has greatly improved sensitivity as compared with the photoreceptor using a pigment with low crystallinity after synthesis. In addition, the amount of potential fluctuation during repeated use is small and good.

Examples 6 to 8 The following charge-transporting substances were used for the charge-transporting substance used in Example 4.

Embedded image Charge transport material B

Embedded image Charge transport material C

Embedded image An electrophotographic photoreceptor was prepared in the same manner as in Example 4 except that the above was replaced with Example 4, and the same evaluation as in Example 4 was performed. Table 3 shows the results.

[0053]

[Table 3]

It can be seen that even when the charge transport material is changed as described above, a photosensitive member having high sensitivity and little potential fluctuation can be obtained.

Example 9 An electrophotographic photosensitive member was prepared by applying the charge generation layer and the charge transport layer in Example 3 in reverse order.

The photosensitive member was used as an electrostatic tester (trade name: EPA)
-8100, manufactured by Kawaguchi Electric Co., Ltd.). The evaluation was first set so that the surface potential was 700 V by positive corona charging, and then exposed to monochromatic light of 802 nm separated by a monochrome meter to reduce the surface potential to 20 V.
The light amount when the voltage dropped to 0 V was measured and defined as sensitivity. As a result, the sensitivity was 0.59 μJ / cm ² .

Example 10 On the charge generation layer formed in Example 5, 2, 4, 7
-5 g of trinitro-9-fluorenone and poly-4,4 '
5 g of -dioxydiphenyl-2,2-propane carbonate (molecular weight 300,000) is added to 50 parts of tetrahydrofuran.
The solution dissolved in g was applied with a Myer bar to form a charge transport layer having a thickness of 23 μm after drying. The sensitivity of the produced electrophotographic photosensitive member was evaluated in the same manner as in Example 9.
However, the charging was positive. As a result, the sensitivity is 0.5
It was 6 μJ / cm ² .

Example 11 0.5 g of bisazo pigment 1-4 was dispersed together with 9.5 g of tetrahydrofuran in a paint shaker for 5 hours. A solution in which 5 g of the same charge transporting substance as used in Example 1 and 5 g of polycarbonate were dissolved in 40 g of tetrahydrofuran was added, and the mixture was further shaken for 1 hour. The coating solution thus prepared was applied to an aluminum support with a Myer bar and dried to form a photosensitive layer having a thickness of 20 μm, thereby preparing an electrophotographic photosensitive member. With respect to this electrophotographic photosensitive member, the sensitivity of the electrophotographic photosensitive member was evaluated in the same manner as in Example 9. However, it was positively charged. As a result, the sensitivity was 0.61 μJ / cm ² .

From the examples, it can be seen that the electrophotographic photosensitive member of the present invention has excellent sensitivity regardless of the form.

[0060]

According to the electrophotographic photoreceptor of the present invention, by incorporating a specific bisazo pigment having enhanced crystallinity into the photosensitive layer, the sensitivity characteristics are greatly improved, and the potential stability upon repeated use is good. Has a remarkable effect. Further, the same effects can be obtained in a process cartridge and an electrophotographic apparatus to which the electrophotographic photosensitive member of the present invention is applied.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of Sample 1-1 obtained in Production Example 1.

FIG. 2 is an X-ray diffraction diagram of Sample 1-2 obtained in Production Example 1.

FIG. 3 is an X-ray diffraction diagram of Sample 1-3 obtained in Production Example 1.

FIG. 4 is an X-ray diffraction diagram of Sample 1-4 obtained in Production Example 1.

FIG. 5 is an X-ray diffraction diagram of Comparative Sample 1 obtained in Production Example 1.

FIG. 6 is an X-ray diffraction pattern of Sample 2 obtained in Production Example 2.

FIG. 7 is an X-ray diffraction diagram of Comparative Sample 2 obtained in Production Example 2.

FIG. 8 is a process card having the electrophotographic photosensitive member of the present invention.
FIG. 2 is a diagram illustrating a schematic configuration of an electrophotographic apparatus having a cartridge.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic photosensitive member of the present 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

Claims (4)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer is coated with X-rays by Cu-Kα radiation.
5.1 ° of Bragg angle 2θ in line diffraction (± 0.2
°) and 26.8 ° (± 0.2 °), and the half-widths of the peaks are 0.7 ° or less and 1.0 ° or less, respectively, in the following general formula ( An electrophotographic photoreceptor comprising the bisazo pigment represented by 1). General formula (1) (In the formula, R represents a methyl group or an ethyl group. 2. The electrophotographic photosensitive member according to claim 1, wherein at least two layers of a charge generation layer containing the bisazo pigment according to claim 1 and a charge transport layer are provided on a conductive support. 3. The electrophotographic photosensitive member according to claim 1, and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported, and are detachably attached to an electrophotographic apparatus main body. A process cartridge characterized by the following. 4. 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.