JP2000298361A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure excellent photosensitivity and to stably obtain an excellent image even after repeated use by forming a protective layer consisting essentially of an electric charge transferring material and a bonding resin containing a copolymer having specified constituent units and continuously carrying out two or more drying steps at different drying temperatures after the formation of the protective layer by coating. SOLUTION: The electrophotographic photoreceptor consists essentially of a substrate, a photosensitive layer and a protective layer consisting essentially of an electric charge transferring material and a bonding resin containing a copolymer having constituent units of formulae I-III. After the formation of the protective layer by coating, two or more drying steps are continuously carried out at different drying temperatures. In the formulae I and II, R1-R16 are each H, halogen or 1-4C alkyl. In the formula III, R17 is 2-6C alkylene or alkylidene, R18-R21 are each 1-3C alkyl, phenyl or substituted phenyl and (n) is an integer of 1-200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art An electrophotographic photosensitive member has, of course, the required sensitivity, electrical characteristics and optical characteristics according to the electrophotographic process to be applied. Requires durability against external electrical and mechanical forces such as charging, exposure, development, transfer and cleaning. Specifically, it is required to have durability against electrification or sensitivity deterioration due to energization, fluctuation in electrification or sensitivity due to exposure, abrasion or scratching of the photoconductor surface due to rubbing, and deterioration of the photoconductor due to ozone or NOx and image flow. Is done.

[0003]

In view of the above-described characteristics, it is conceivable to add a material having lubricity to the photosensitive layer in order to prevent abrasion, scratches and image deletion on the surface of the photosensitive member. However, since some of the components of such a material have a property of migrating to the surface side, they were uniformly dissolved in the paint, but migrated to the surface during film formation and were not uniformly dispersed. Therefore, although the photoreceptor has a high lubricating property at the initial stage, when the photoreceptor is scraped to some extent, since the components are not distributed, the scraping is increased.

An object of the present invention is to provide an electrophotographic photoreceptor having an excellent photoreceptor and capable of stably obtaining excellent images even when used repeatedly, an electrophotographic apparatus using the electrophotographic photoreceptor, It is to provide a process cartridge.

[0005]

The electrophotographic photoreceptor of the present invention comprises at least a support, a photosensitive layer and a protective layer. The protective layer comprises at least a charge transport material and a resin. Constituent units shown,

[0006]

Embedded image (In the formula, R _{1 to} R ₈ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.) A structural unit represented by the formula (2)

[0007]

Embedded image (In the formula, R _{9 to} R ₁₆ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.) And a structural unit represented by the formula (3)

[0008]

Embedded image (Wherein, R ₁₇ is an alkylene group or an alkylidene group having 2 to 6 carbon atoms, R _{18 to} R ₂₁ are an alkyl group having 1 to 3 carbon atoms,
A phenyl group or a substituted phenyl group, n represents an integer of 1 to 200; ), And after the application of the protective layer, a drying step at a different drying temperature is continuously performed twice or more.

Further, in the electrophotographic photoreceptor of the present invention, the weight α of the structural unit represented by the formulas (1) and (2) and the weight β of the structural unit represented by the formula (3) are 0.01 ≦ β /
(Α + β) ≦ 0.1.

In the electrophotographic photoreceptor of the present invention, the content of the copolymer having the structural units represented by the above formulas (1), (2) and (3) is based on all resin components contained in the surface layer. 25% by weight or more.

Further, the method of manufacturing an electrophotographic photosensitive member according to the present invention is characterized in that the protective layer is formed by spray coating.

Further, the electrophotographic photoreceptor of the present invention is characterized in that the protective layer contains fluororesin-containing resin fine particles.

As a result, the protective layer can be provided with further high lubricity.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The photosensitive layer of the electrophotographic photoreceptor of the present invention contains a charge generating substance, a charge transporting substance and a binder resin, but contains the charge generating substance and the charge transporting substance in the same layer. It is roughly classified into a so-called single layer, a so-called stacked type having a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance. The laminate type is further classified into a type in which a support, a charge generation layer, and a charge transport layer are laminated in this order, and a type in which a support, a charge transport layer, and a charge generation layer are laminated in this order.

When the photosensitive layer is of a laminated type, the charge generating layer is made of an inorganic charge generating substance such as selenium, selenium-ter and amorphous silicon; a pyrylium dye, a thiapyrylium dye, an azulenium dye, a thiacyanine dye and a quinocyanine dye. Cationic dyes such as dyes; Squarium salt dyes; Phthalocyanine pigments; Anthantrone pigments; Polycyclic quinone pigments such as dibenzopyrene quinone pigments and pyranthrone pigments; Indigo pigments; Quinacridone pigments and azo pigments As a charge generating substance. These can be used alone or in combination. The charge generation layer is formed as a vapor deposition layer on a conductive support by a vacuum vapor deposition apparatus, or a liquid in which the above-described charge generation substance is dispersed in a binder resin using an appropriate solvent is applied and dried. Can be formed as a coating layer.

Examples of the binder resin include a wide range of insulating resins such as polyvinyl butyral, polyarylate (condensed polymer of bisphenol A and phthalic acid), polycarbonate, polyester, polyvinyl acetate, acrylic resin, polyacrylamide, and the like. Resins such as polyamide, cellulosic resin, urethane resin, epoxy resin and polyvinyl alcohol can be mentioned.
Organic photoconductive resins such as N-vinylcarbazole and polyvinylpyrene can also be mentioned. The proportion of the binder resin in the charge generation layer is preferably 90% by weight or less, and particularly preferably 50% by weight or less, based on the total weight of the charge generation layer. However, in the case of the type in which the charge generation layer is formed on the charge transport layer, the charge generation layer must always contain a binder resin, and the proportion thereof is 10% by weight based on the total weight of the charge generation layer. It is preferably at least
In particular, it is preferably at least 30% by weight.

The charge generation layer has a thickness of 0.001 to 0.001.
6 μm, particularly 0.01-1 μm
It is preferred that

The charge transport layer comprises a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene and phenanthrene in the main chain or side chain; a nitrogen-containing ring compound such as indole, carbazole, oxadiazole and pyrazoline; a hydrazone compound And a solution prepared by dissolving a charge transport material such as a styryl compound in a binder resin using an appropriate solvent, followed by drying.

Examples of usable binder resins include polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester, alkyd resin, and polycarbonate. , Polyurethane, styrene-butadiene copolymer, styrene-acrylic copolymer, styrene-acrylonitrile copolymer and styrene-maleic acid copolymer. In addition to such an insulating resin, an organic photoconductive polymer such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene can be used. Among them, acrylic resin, methacrylic resin, polycarbonate and styrene-acryl copolymer are particularly preferred. The compounding ratio of the binder resin and the charge transport material is preferably such that the charge transport material is 20 to 80% by weight based on the total weight of the charge transport layer,
In particular, it is preferably 30 to 70% by weight.

The charge transport layer has a thickness of 5 to 35 μm.
It is particularly preferable that the thickness be 7 to 30 μm.

When the photosensitive layer is of a single layer type, a solution in which the above-mentioned charge generating substance and the above-mentioned charge transporting substance are dispersed and dissolved in the above-mentioned binder resin is applied on a conductive support, and dried. Can be formed.

At this time, the thickness of the photosensitive layer is preferably from 5 to 35 μm, particularly preferably from 7 to 30 μm.

In the present invention, a layer mainly composed of a resin, that is, a so-called undercoat layer may be provided between the conductive support and the photosensitive layer. The undercoat layer has a function of controlling the injection of the carrier from the conductive support and improving the adhesion between the support and the photosensitive layer. The undercoat layer is mainly composed of a resin, but may contain the above-mentioned metal, alloy, oxides, salts thereof, and a surfactant. Specific examples of the resin used for the undercoat layer include polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, and allyl. Resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin, and the like. The film thickness is 0.0
It is preferably 5 to 7 μm, particularly 0.1 to 2 μm.
m is preferable.

The protective layer is always provided on the photosensitive layer. The protective layer is mainly made of resin, for example, polyester, polyurethane, polyacrylate, polyethylene,
Polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide-
Examples include imide, nylon, polysulfone, polyallyl ether, polyacetal, and butyral resin. The thickness of the protective layer is 0.05 to 15 μm, preferably 1
〜１０10 μm.

Further, a structural unit represented by the following formula (1) in the protective layer:

[0026]

Embedded image (In the formula, R _{1 to} R ₈ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.) A structural unit represented by the formula (2)

[0027]

Embedded image (In the formula, R _{9 to} R ₁₆ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.) And a structural unit represented by the formula (3)

[0028]

Embedded image (Wherein, R ₁₇ is an alkylene group or an alkylidene group having 2 to 6 carbon atoms, R _{18 to} R ₂₁ are an alkyl group having 1 to 3 carbon atoms,
A phenyl group or a substituted phenyl group, n represents an integer of 1 to 200; Examples of the copolymer having ()) are shown below.

In order to have the lubricating effect of the copolymer in the protective layer, the content is 25% by weight or more, preferably 30% by weight or more and 100% with respect to all resin components.

[0030]

[Table 1] Preferred examples include Structural Unit Examples 1, 2 and 5, and particularly Structural Unit Example 1.

Table 2 shows specific examples of the structural unit represented by the formula (2). Preferred examples are structural unit example 8,
9 and 12, and particularly the structural unit example 8.

[0032]

[Table 2] Tables 3 and 4 show specific examples of the structural unit represented by the formula (3). A preferred example is Structural Unit Example 15.

[0033]

[Table 3]

[0034]

[Table 4] Formulas (1), (2) and (3) used in the present invention
The copolymer having the structural unit represented by the following formula (4)
Can be obtained by interfacially polymerizing bisphenols represented by the following formulas and bisphenols represented by the following formula (5) in the presence of phosgene, carbonate, or chloroformate.

Equation (4)

[0036]

Embedded image Equation (5)

[0037]

Embedded image (Wherein, R ₁₇ to R ₂₁ are synonymous with R ₁₇ to R ₂₁ in Formula (3)) In the electrophotographic photoreceptor of the present invention, the weight of the structural unit represented by the formula (1) and (2) alpha When the constituent unit represented by the formula (3) is β, the value of β / (α + β) is preferably in the range of 0.01 to 0.9, and particularly in the range of 0.01 to 0.1. It is preferred that

In the formula (3), n represents an integer of 1 to 200, and particularly preferably 5 to 100. Examples of R ₃₁ include ethylene, propylene, isopropylene, butylene and pentylene, and particularly preferred are ethylene, propylene and isopropylene.

The protective layer may contain a charge transporting material to maintain the charge transporting property, and fluorine atom-containing resin fine particles to reduce the surface frictional resistance. As a specific example, as the charge transport material, a pyrene compound, N
-Alkyl carbazole compounds, hydrazone compounds,
N, N-dialkylaniline compounds, diphenylamine compounds, triphenylamine compounds, triphenylmethane compounds, pyrazoline compounds, styryl compounds, stilbene compounds, polynitro compounds, polycyano compounds, and pendant polymers in which these compounds are fixed on a polymer. No. Examples of the fluorine atom-containing resin fine particles include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, and tetrafluoroethylene-hexafluoropropylene copolymer , A tetrafluoroethylene-ethylene copolymer, a tetrafluoroethylene-hexafluoropropylene-perfluorofluorovinyl ether copolymer, and the like.

The conductive support used in the present invention includes, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold and platinum. In addition, plastics (eg, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) formed by coating such metals and alloys by vacuum evaporation, and conductive particles (eg, carbon black and silver particles) are appropriately bonded. A support coated on a plastic, metal or alloy support as described above, or a support in which conductive particles are impregnated in a plastic or paper together with a resin to be used can be used. Examples of the shape of the support include a drum shape, a sheet shape, and a belt shape, and it is preferable that the shape is most suitable for the applied electrophotographic apparatus.

As a method for producing the electrophotographic photosensitive member of the present invention, methods such as vapor deposition and coating are used. The method by coating
Films of various compositions can be formed in a wide range from a thin film to a thick film. Specifically, it is applied by a method such as bar coating, knife coating, dip coating, spray coating, beam coating, electrostatic coating, roll coating, attritor, and powder coating.

The surface layer is formed by spray coating.

The electrophotographic photoreceptor of the present invention can be applied to general electrophotographic devices such as copiers, laser printers, LED printers, and liquid crystal shutter printers. It can be widely applied to devices such as plate making and facsimile.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus using a process cartridge having an 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 rotated around an axis 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 at a predetermined positive or negative potential by the primary charging means 3, and then, the time-series electricity of the target image information output from exposure means (not shown) such as slit exposure or laser beam scanning exposure. The exposure light 4 which has been enhanced and modulated according to the digital image signal is received. Thus, an electrostatic latent image corresponding to the target image information 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 image thus developed 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 to a transfer material 7 fed and fed. Then, the toner image formed and carried on the surface of the photoconductor 1 is sequentially transferred by the transfer unit 6.

The transfer material 7 to which the toner image has been transferred 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 an image formed product (print, copy) outside the apparatus. You.

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 repeated image formation. 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, 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, and is detachably attached to 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 exposure light 4 is reflected light or transmitted light from the original, or the original is read by a sensor, converted into a signal, and a laser beam is emitted in accordance with the signal. Beam scanning, LED
Light emitted by driving the 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 CRT printers, LED printers, liquid crystal printers, and laser plate making.

[0052]

The present invention will be described in more detail with reference to the following examples. In the examples, "parts" indicates parts by weight.

Example 1 A solution prepared by dissolving 10 parts by weight of nylon (M-4000, manufactured by Toray Industries, Inc.) in a mixed solution of 100 parts by weight of methanol and 90 parts by weight of isopropanol was used. By dip coating on an aluminum cylinder having a length of 360 mm and drying at 90 ° C. for 20 minutes, an undercoat layer having a thickness of 1.0 μm was formed.

Next, a trisazo pigment 1 represented by the following formula:
0 parts by weight,

[0055]

Embedded image A solution of 5 parts by weight of polycarbonate (bisphenol A type, number average molecular weight 20,000) dissolved in 600 parts by weight of cyclohexanone was added and dispersed using a sand mill to obtain a solution for a charge generation layer. This solution was dip-coated on the undercoat layer and dried at 120 ° C. for 20 minutes to form a charge generation layer having a thickness of 0.15 μm.

Next, 20 parts by weight of a compound represented by the following formula:

[0057]

Embedded image And 20 parts by weight of polycarbonate (bisphenol Z type, number average molecular weight 16,000) were added to chlorobenzene 800
The solution for the charge transporting layer was obtained by dissolving in parts by weight using a ball mill. This solution was applied onto the charge generation layer by dip coating and dried at 130 ° C. for 45 minutes to form a charge transport layer having a thickness of 15 μm.

3 parts by weight of a polymer represented by the following formula (number average molecular weight: 24,000)

[0059]

Embedded image 10 parts by weight of a compound represented by the following formula,

[0060]

Embedded image Then, 7 parts by weight of polycarbonate (bisphenol type, number average molecular weight 40,000) were dissolved in 400 parts by weight of chlorobenzene and 400 parts by weight of dichloromethane using a ball mill to obtain a solution for spray coating. This solution was applied by spray coating, dried at 60 ° C. for 20 minutes, and then dried at 110 ° C. for 40 minutes to form a 5 μm protective layer to obtain an electrophotographic photoreceptor of the present invention.

Example 2 In Example 1, the thickness of the charge transport layer was set to 20 μm, and then 12 parts by weight of a polycarbonate (bisphenol Z type, number average molecular weight: 85,000), and a polycarbonate represented by the following formula: (Number average molecular weight 80,000) 12 parts by weight

[0062]

Embedded image Parts by weight of the compound 10 represented by the following formula

[0063]

Embedded image Is chlorobenzene 400 parts by weight, dichloromethane 400
The solution for the protective layer was obtained by dissolving in parts by weight using a ball mill. This solution was spray-coated on the charge transport layer to obtain a 1 μm protective layer. Thereafter, hot air at 80 ° C. was applied for 1 minute to dry. The above operation is repeated until the thickness of the protective layer becomes 4 μm.
Drying was performed for 5 minutes.

Example 3 In Example 1, 1.5 parts by weight of polytetrafluoroethylene particles (Lupron L-2, manufactured by Daikin Industries, Ltd.) were added to the spray coating solution, followed by coating in the same manner. .

(Example 4) In Example 2, polytetrafluoroethylene particles (Rublon L-
2, manufactured by Daikin Industries, Ltd.) and spray-coated in the same manner to obtain a protective layer.

Example 5 The coating film of Example 1 was formed on an aluminum sheet.

Comparative Example 1 A charge generation layer was formed on an aluminum sheet in Example 1. Next, 20 parts by weight of a compound represented by the following formula,

[0068]

Embedded image And 18 parts by weight of a polycarbonate (bisphenol Z type, number average molecular weight 20,000) and 2 parts by weight of a polymer represented by the following formula (number average molecular weight 20,000)

[0069]

Embedded image Was dissolved in 140 parts by weight of chlorobenzene using a ball mill to obtain a charge transport layer liquid. This solution was dip-coated on the charge generation layer and dried at 100 ° C. for 40 minutes to obtain a charge transport layer having a thickness of 25 μm.

The photosensitive members of Examples 1 to 4 were mounted on a digital color copier (trade name: CLC-700) manufactured by Canon Inc.
After passing 50,000 sheets, clear images were obtained from the beginning to the end.

In the case of Comparative Example 1, image fogging occurred at about 16,000 sheets, and black streaks due to poor cleaning occurred at about 18,000 sheets. An image could not be formed on 20,000 sheets.

The results of measuring the amount of shaving of the protective layer every 10,000 sheets are shown in the table below.

[0073]

[Table 5] In Example 5 and Comparative Example 1, the amount of Si was measured in the direction of film thickness distribution by ESCA. As shown in FIG. 2, in the protective layer of the present invention, the distribution of Si was almost the same in the direction of film thickness. On the other hand, it was found that in Comparative Example 1, a large amount was distributed near the surface.

[0074]

As described above, according to the present invention, in order to prevent abrasion, scratches and image deletion on the surface of the photoreceptor, the photosensitive layer is superior to the conventional one in which a material having lubricity is added. It has electrophotographic properties and can stably provide excellent images even when used repeatedly.

[Brief description of the drawings]

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

FIG. 2 is a graph showing the results of measuring the amount of Si in Example 5 and Comparative Example 1 in the direction of film thickness distribution.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 axis 3 Charging means 4 Exposure light 5 Developing means 6 Transfer means 7 Transfer material 8 Fixing means 9 Cleaning means 10 Pre-exposure light 11 Process cartridge 12 Rail

Claims (7)

[Claims] 1. A photoreceptor comprising a conductive support, a photoconductive layer and a protective layer, wherein the protective layer comprises at least a charge transport material and a binder resin, and the binder resin is represented by the following formula (1). Structural unit, (In the formula, R _{1 to} R ₈ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.) Structural unit represented by the formula (2): (In the formula, R _{9 to} R ₁₆ represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms.) And a structural unit represented by the formula (3): (Wherein, R ₁₇ is an alkylene group or an alkylidene group having 2 to 6 carbon atoms, R _{18 to} R ₂₁ are an alkyl group having 1 to 3 carbon atoms,
A phenyl group or a substituted phenyl group, n represents an integer of 1 to 200; An electrophotographic photoreceptor comprising a copolymer having the formula (1), and wherein a drying step having a different drying temperature is continuously performed twice or more after coating of the protective layer. 2. The weight α of the structural unit represented by the formulas (1) and (2) and the weight β of the structural unit represented by the formula (3) are 0.01 ≦ β / (α + β) ≦ 0.1. Claim 1
2. The electrophotographic photoreceptor of claim 1. 3. The content of the copolymer having the structural units represented by the formulas (1), (2) and (3) is at least 25% by weight based on all the resin components contained in the surface layer. Item 1
The electrophotographic photosensitive member according to the above. 4. The electrophotographic photosensitive member according to claim 1, wherein the protective layer is formed by spray coating. 5. The electrophotographic photoreceptor according to claim 1, wherein the protective layer contains fluororesin-containing resin fine particles. 6. The electrophotographic photosensitive member according to claim 1, wherein the charging unit charges the electrophotographic photosensitive member, and the electrophotographic photosensitive member on which an electrostatic latent image is formed is a toner. A process cartridge which is integrally supported together with at least one means selected from the group consisting of a developing means for developing and a cleaning means for collecting residual toner on the photoreceptor after the transfer step, and is detachable from the main body of the electrophotographic apparatus. . 7. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. An electrophotographic apparatus having an exposure unit for forming, a developing unit for developing an electrophotographic photosensitive member on which an electrostatic latent image is formed with toner, and a transfer unit for heating and transferring a toner image on a transfer material.