JPH09134020A - Electrophotographic photoreceptor, electrophotographic device equipped with that photoreceptor and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cracks in a charge transfer layer even when a photoreceptor is not used for a long time by incorporating a specified arylamine compd. into a photosensitive layer. SOLUTION: This photoreceptor consists of a base body and a photosensitive layer formed on the base body. The photosensitive layer contains an arylamine compd. expressed by formula. In formula, R1 is an alkyl group which may have substituents, aralkyl group which may have substituents, or aromatic hydrocarbon ring group which may have substituents, R2 -R8 are hydrogen atoms, halogen atoms, alkyl groups which may have substituents, alkoxy groups which may have substituents, or amino groups which may have substituents, and Ar is an alkyl group which may have substituents, aromatic hydrocarbon ring group which may have substituents, or aromatic heteroring which may have substituents. Therefore, the obtd. photoreceptor has good sensitivity and stable electrophotographic characteristics are obtd. even when it is repeatedly used.

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, an electrophotographic apparatus equipped with this electrophotographic photosensitive member, and a process cartridge.

[0002]

2. Description of the Related Art Conventionally, selenium has been used as an electrophotographic photoreceptor.
Inorganic photoreceptors having a photosensitive layer containing zinc oxide, cadmium, etc. as a main component have been widely used. The inorganic photoreceptor has problems such as difficulty in forming a photosensitive layer, poor plasticity, and high manufacturing cost. Furthermore, inorganic photoconductive materials are generally highly toxic, and have great restrictions on production and handling.

On the other hand, an organic photoconductor containing an organic photoconductive compound as a main component has many advantages such as supplementing the above-mentioned drawbacks of an inorganic photoconductor and has been attracting attention in recent years, and many proposals have been made so far. Some have been put to practical use.

As such an organic photoreceptor, poly-N
An electrophotographic photoreceptor containing a charge transfer complex formed from a photoconductive polymer represented by vinylcarbazole and a Lewis acid such as 2,4,7-trinitro-9-fluorenone as a main component has been proposed. . These organic photoconductive compounds are superior to the inorganic photoconductive compounds in terms of lightness and film formability, but in terms of sensitivity, durability, stability due to environmental changes, etc., the inorganic photoconductive compounds are It is inferior to, and is not always satisfactory.

On the other hand, a function-separated type electrophotographic photoreceptor in which the charge generation function and the charge transport function are respectively assigned to different substances has a remarkable improvement in sensitivity and durability, which have been disadvantages of conventional organic photoreceptors. Brought. Such a function-separated type photoreceptor has the advantages that the material selection range of the charge generating substance and the charge transporting substance is wide, and that an electrophotographic photoreceptor having desired characteristics can be prepared relatively easily.

As the charge generating substance, various kinds of azo pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, pyrylium salt dyes and the like have been conventionally known. Among them, many structures have been proposed for azo pigments in terms of high light resistance, high charge generation ability, easy material synthesis, and the like.

On the other hand, examples of the charge transport material include pyrazoline compounds disclosed in JP-B-52-4188 and JP-B-55-188.
-42380 and JP-A-55-52063, hydrazone compounds, JP-A-3-114058 and JP-A-5-53349, triphenylamine compounds, JP-A-54-151955 and JP-A-54-151955. 58
The stilbene compound disclosed in Japanese Patent Publication No. 198043 is known.

[0008]

If the conventional photoconductor is not used for a long time while being mounted in a copying machine or a laser printer, cracks may occur in the charge transport layer, which causes image defects.

An object of the present invention is to provide an electrophotographic photosensitive member which does not cause cracks in the charge transport layer even if it is not used for a long period of time, an electrophotographic apparatus and a process cartridge equipped with the electrophotographic photosensitive member. is there.

Another object of the present invention is to provide an electrophotographic photosensitive member which has good sensitivity and stable electrophotographic characteristics even after repeated use, an electrophotographic apparatus and a process cartridge equipped with the electrophotographic photosensitive member. It is in.

[0011]

The electrophotographic photoreceptor of the present invention has a support and a photosensitive layer formed on the support, and the photosensitive layer has an aryl represented by the following general formula (1). It contains an amine compound.

[0012]

[Outside 3] In the general formula (1), R ₁ represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aromatic hydrocarbon ring group which may have a substituent. R ₂ -R ₈
Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an amino group which may have a substituent. Ar represents an alkyl group which may have a substituent, an aromatic hydrocarbon ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

In the electrophotographic apparatus of the present invention, the electrophotographic photosensitive member described above, a charging unit that charges the electrophotographic photosensitive member, and an electrostatic latent image by exposing the charged electrophotographic photosensitive member to an image. And an developing device for developing the electrophotographic photosensitive member on which the electrostatic latent image is formed with toner.

In the process cartridge of the present invention, at least one of the charging means, the developing means, and the cleaning means is constructed together with the above electrophotographic photosensitive member.

The electrophotographic photoreceptor of the present invention has a support and a photosensitive layer formed on the support, and the photosensitive layer contains an arylamine compound represented by the following general formula (1). It is a thing.

[0016]

[Outside 4] In the general formula (1), R ₁ represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aromatic hydrocarbon ring group which may have a substituent. R ₂ -R ₈
Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an amino group which may have a substituent. Ar represents an alkyl group which may have a substituent, an aromatic hydrocarbon ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

In the general formula (1), the alkyl group represented by R ₁ -R ₈ and Ar preferably has 1 to 4 carbon atoms, that is, methyl, ethyl, propyl and butyl. R
_{As the} aralkyl group represented by ₁ , benzyl, phenethyl and the like are preferable. As the aromatic hydrocarbon ring group represented by R ₁ , phenyl, naphthyl, biphenyl and the like are preferable, and a phenyl group having an alkyl group is particularly preferable.
Further, a phenyl group having an alkyl group in the para position to the nitrogen atom is preferable, and a methyl group is particularly preferable as the alkyl group in the para position to the nitrogen atom.

The halogen atom represented by R ₂ -R ₈ is preferably a fluorine atom, a chlorine atom, a bromine atom or the like. R
_The alkoxy group represented by _2- R ₈ is methoxy,
Ethoxy, propoxy and the like are preferred. As the aromatic hydrocarbon ring group represented by Ar, phenyl, naphthyl and the like are preferable. As the aromatic heterocyclic group represented by Ar, pyridyl, indolyl, benzothienyl and the like are preferable. The alkyl group, aralkyl group, aromatic hydrocarbon ring group, alkoxy group, amino group and the substituent that the aromatic heterocyclic group may have are methyl, ethyl, propyl,
Examples thereof include an alkyl group such as butyl, an alkoxy group such as methoxy and ethoxy, a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom.

Preferred examples of the arylamine compound represented by the general formula (1) will be given below. However,
It is not limited to these compounds.

[0020]

[Outside 5]

[0021]

[Outside 6]

[0022]

[Outside 7]

[0023]

[Outside 8]

[0024]

[Outside 9]

Next, preferable synthetic examples of the above-mentioned compound examples will be shown.

(Synthesis method of compound example No. 2) 5.0 g of 9-ethylcarbazole (40 ml of acetic acid-water (9: 1) to 25.6 mmol, 3.3 g of iodine (13.0 mmo)
1), 2.5 g of 30% aqueous hydrogen peroxide and 1.8 g of 97% sulfuric acid were added, and the mixture was heated with stirring at 60 ° C. for 2 hours. After allowing to cool, the mixture was diluted with water and then extracted with toluene. The toluene layer was concentrated, and the obtained residue was separated and purified with a silica gel column to obtain 5.3 g of 3-iodo-9-ethylcarbazole (yield 65%).

Next, 5 g (15.5 mmol) of 3-iodo-9-ethylcarbazole and 0.8 g of p-toluidine.
(7.8 mmol), 13.8 g of anhydrous potassium carbonate and 3 g of copper powder were added to 50 ml of o-dichlorobenzene, and heated and refluxed for 14 hours while stirring in a nitrogen stream. After cooling, suction filtration was performed, and o-dichlorobenzene was removed from the filtrate under reduced pressure. The residue was separated and purified with a silica gel column to obtain 3.2 g of Compound Example 2 (yield 42%).

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION In the electrophotographic photoreceptor of the present invention, the charge transporting substance of the above-mentioned arylamine compound and a suitable charge generating substance are used in combination.

Examples of the constitution of the photosensitive layer include the following forms.

(A) A charge-generating layer containing a charge-generating substance and a charge-transporting layer containing a charge-transporting substance are laminated in this order from the support side. (B) A charge-transporting layer and a charge-generating layer are sequentially formed from the support side. Laminated product (c) Containing both charge generating substance and charge transporting substance together (d) Laminating product comprising charge generating layer and charge transporting layer containing charge generating substance and charge transporting substance in this order from the support side

Since the triarylamine compound used in the present invention has a high hole-transporting ability, it can be used as a charge-transporting substance. When the form of the photosensitive layer is (a), it is preferably negatively charged, when it is (b), it is preferably positively charged, and when it is (c) or (d), it can be used either positively or negatively.

Of the constitutions of (a) to (d), particularly (a)
Is preferable.

Examples of the charge generating substance include azo pigments (eg, monoazo, bisazo, trisazo, etc.), phthalocyanine pigments (eg, metal phthalocyanine, nonmetal phthalocyanine), and indigo pigments (eg, indigo,
Thioindigo etc.), polycyclic quinone pigments (eg anthraquinone, pyrene quinone etc.) Perylene pigments (eg perylene anhydride, perylene imide etc.), squalium dyes, pyrylium, thiopyrylium salts, triphenylmethane dyes etc. To be

Also, an inorganic material such as selenium, selenium-tellurium or amorphous silicon can be used as the charge generating substance.

In the present invention, it is preferable to use titanyl phthalocyanine having the following structure as a charge generating substance.

[0036]

[Outside 10]

In addition to the arylamine compound used as the charge transport material in the present invention, a known charge transport material may be contained in the photosensitive layer.

When the photosensitive layer is a single layer, the thickness of the photosensitive layer is 5
˜100 μm is preferable, and further preferably 10 to 60 μm. It is preferable that the single photosensitive layer contains 10 to 70% by weight, and further 20 to 70% by weight of each of the charge generating substance and the charge transporting substance.

When the photosensitive layer has a laminated structure, the thickness of the charge generation layer is preferably 0.001 to 5 μm, more preferably 0.01 to 2 μm, and the thickness of the charge transport layer is 5 to 40 μm, more preferably 10 μm.
-30 μm is preferable. The charge generation layer preferably contains 20 to 100% by weight, more preferably 60 to 100% by weight of the charge generation substance. The charge transport layer preferably contains the arylamine compound used in the present invention in an amount of 10 to 500 parts by weight based on 100 parts by weight of the binder resin.

In the electrophotographic photosensitive material of the present invention, the material used for the photosensitive layer is combined with vacuum vapor deposition, sputtering, CVD or a suitable binder resin, and a dip coating method, a spray coating method, a spinner coating method, a roller coating method, It can be obtained by forming a film on a support using a coating method such as a Mayer bar coating method or a blade coating method.

The binder resin used in the photosensitive layer (in the case of a laminated structure, the charge generation layer and the charge transport layer) can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyarylate resin, Butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, Examples of the vinyl chloride-vinyl acetate copolymer resin,
It is not limited to these. These may be used alone or in combination of two or more as a copolymer. Furthermore, polyvinylcarbazole and polyvinylanthracene can be used as the binder resin for the charge transport layer.

The support is made of a metal or alloy such as aluminum, aluminum alloy, copper, titanium, stainless steel, or a polymer material such as polyethylene terephthalate, polybutylene terephthalate, phenol resin, polypropylene or polystyrene, and further hard paper. It can be manufactured using the material. The shape of the support is preferably cylindrical, belt-shaped or sheet-shaped. When the material constituting the support has a high volume resistance, it is necessary to conduct a conductive treatment. The conductive treatment can be performed by forming a conductive thin film on the support or by dispersing a conductive substance in the support.

In the electrophotographic photoreceptor of the present invention, a protective layer may be provided on the photoconductive layer. The protective layer is mainly composed of a resin. Examples of the material forming the protective layer include polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon, phenol resin, acrylic resin. , Silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, butyral resin and the like. The thickness of the protective layer is 0.05 to 15 μm,
10 μm is preferable.

An undercoat layer may be provided between the support and the photosensitive layer. The undercoat layer functions as a charge injection control at the interface and as an adhesive layer. The undercoat layer is mainly composed of a binder resin, but may contain a conductive material, a surfactant and the like. As the binder resin forming the undercoat layer, polyester, polyurethane, polyarylate, polyethylene, polystyrene, polybutadiene, polycarbonate, polyamide, polypropylene, polyimide, polyamideimide, polysulfone, polyallyl ether, polyacetal, nylon,
Phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin,
Butyral resin etc. are mentioned. The thickness of the undercoat layer is preferably 0.05 to 7 μm, more preferably 0.1 to 2 μm.

If desired, a sensitizer, an antioxidant, an ultraviolet absorber or a plasticizer may be added to the photosensitive layer.

Next, an electrophotographic apparatus using the process cartridge of the present invention will be described.

In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around a shaft 2 in a direction of an arrow at a predetermined peripheral speed. In the course of rotation of the photoconductor 1, the peripheral surface of the photoconductor 1 is uniformly charged with a predetermined positive or negative potential, and then an image exposing unit 4 such as a slit exposure unit or a laser beam scanning exposure unit (not shown) exposes the image. Receive. 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 the developing means 5.
The toner-developed image is developed by the toner, and the developed toner-developed image is transferred to the recording material 7 that is fed between the photosensitive member 1 and the transfer unit 6 in synchronization with the rotation of the photosensitive member 1 from a sheet feeding unit (not shown). The images are sequentially transferred by the transfer means 6. The recording material 7 that has undergone the image transfer is separated from the surface of the photoconductor and is introduced into the image fixing means 8 to undergo the image fixing and is printed out to the outside of the apparatus as a copy. The surface of the photoconductor 1 after the image transfer is cleaned by the cleaning unit 9 to remove the residual toner after transfer, and is further subjected to the static elimination process by the pre-exposure 10 from the pre-exposure unit (not shown), and then repeated. Used for 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, among the components such as the photoconductor 1, the primary charging unit 3, the developing unit 5, and the cleaning unit 9 described above, a plurality of components are collectively configured as a process cartridge 11. 11 may be configured to be detachable from the 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 can be used as a cartridge together with the photosensitive member 1, and can be detachably provided in the apparatus main body by using a guide unit such as a rail 12 of the apparatus main body. The image exposure 4 is reflected light or transmitted light from the document, or light from a laser driven by a signal, an LED, or a liquid crystal shutter array.

The electrophotographic photoreceptor of the present invention can be used not only in an electrophotographic copying machine, but also in 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.

[0051]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 4.6 g of a bisazo pigment having the following structural formula was dispersed in a sand mill for 38 hours together with a solution of 2 g of butyral resin (butyralization degree: 65 mol%) dissolved in 100 ml of cyclohexanone, and a coating solution was prepared. Prepared.

[0053]

[Outside 11]

This coating solution was applied onto an aluminum sheet with a Meyer bar so that the film thickness after drying was 0.3 μm, and dried to form a charge generation layer.

Next, as a charge transport material, the above compound example 6 is used.
Of the arylamine compound (7 g), a polycarbonate Z-type resin (weight average molecular weight of 180,000) and 70 g of chlorobenzene are dissolved, and this solution is applied on the charge generation layer with a Meyer bar to form a charge transport layer having a dry film thickness of 19 μm. An electrophotographic photoreceptor of the present invention was prepared.

The prepared electrophotographic photosensitive member was manufactured by Kawaguchi Electric Co., Ltd.
Manufactured by Electrostatic Copy Paper Testing Device Model-SP-428, statically charged at −5 KV corona, held in the dark for 1 second, and then exposed to white light with an illuminance of 20 lux to evaluate charging characteristics. . Charging characteristics measured potential (V _I), the exposure amount E _1/5 necessary for attenuating the 1/5 potential (V ₁₎ when the surface potential V _0, 1 sec to dark decay immediately after charging Evaluated. The results are shown in Table 1.

Further, in order to measure the fluctuations in the light potential and the dark potential when the photoconductor is repeatedly used, an aluminum cylinder having a diameter of 80 mm and a length of 360 mm is used as a support, and the above-mentioned surface of the support is used. The electrophotographic photoreceptor provided with the charge generation layer and the charge transport layer in the same manner was mounted on a PPC copier NP-3825 manufactured by Canon Inc., and continuous copying was performed on 5000 sheets of recording paper by the same machine. Fifty
Light potential 00 sheets copier V _L, the dark portion potential V _D and the residual potential V _R before and after exposure were measured. The initial V
_D and _VL were set to -700V and -200V, respectively. The results are shown in Table 2.

The surface of the electrophotographic photosensitive member prepared as described above was touched with a finger, and then the photosensitive member was allowed to stand for 8 hours at room temperature and normal pressure. In this way, it was observed whether the photosensitive layer had cracks. The results are shown in Table 3.

Examples 2 to 10 Compound example 6 which is the charge transport material used in Example 1
Instead of the above, compound examples 1, 2, 7, 10, 1 exemplified above
Example 2, using the arylamine compounds of 5, 18, 21, 23, and 30 and using the bisazo pigment having the following structural formula as the charge-generating substance, in the same manner as in Example 1
Ten electrophotographic photoreceptors were prepared. Each photoreceptor thus obtained was evaluated in the same manner as in Example 1.

[0060]

[Outside 12]

[0061]

[Table 1]

[0062]

[Table 2]

[0063]

[Table 3]

Comparative Examples 1 to 4 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the following compounds were used in place of the compound example 6 which is the charge transport material used in Example 1. .

For each of the photoreceptors thus obtained, Example 1
Was evaluated in the same way as The results are shown in Table 4-6.

[0066]

[Outside 13]

[0067]

[Table 4]

[0068]

[Table 5]

[0069]

[Table 6]

Example 11 4 g of N-methoxymethylated 6 nylon resin (weight average molecular weight 3000) and alcohol-soluble copolymerized nylon resin (weight average molecular weight 2800) were placed on an aluminum sheet.
0) A solution obtained by dissolving 10 g in 100 g of methanol was applied with a Meyer bar to form an undercoat layer having a film thickness after drying of 0.8 μm.

Next, 10 g of a bisazo pigment having the following structural formula,
5 g of polyvinyl butyral resin (degree of butyralization 68%, weight average molecular weight 34000) and 90 g of dioxane were dispersed in a ball mill for 24 hours. This dispersion was applied onto the previously formed undercoat layer by a blade coating method to form a charge generation layer having a film thickness after drying of 0.3 μm.

[0072]

[Outside 14]

Next, 7 g of the arylamine compound of Compound Example 3 exemplified above as a charge transporting substance and 10 g of polymethylmethacrylate resin (weight average molecular weight 45000) were dissolved in 70 g of chlorobenzene, and this solution was placed on the charge generation layer. It was applied by a blade coating method, and a charge transport layer having a film thickness after drying of 23 μm was formed to prepare an electrophotographic photoreceptor.

The produced electrophotographic photosensitive member was manufactured by Kawaguchi Electric Co., Ltd.
Electrostatic copying paper tester Model-Sp-428 manufactured by Electrostatics Co., Ltd. was used to statically charge a corona of −5 KV in a static system, hold it in the dark for 1 second, and then expose it with a laser to evaluate the charging characteristics. The charging characteristic is that the surface potential V ₀ immediately after charging, the potential (V _I ) when dark-decayed for 1 second, and the exposure amount E _1/5 (μJ / μJ / necessary to attenuate the potential (V ₁ ) to ⅕ cm ² ) was measured and evaluated. A gallium / aluminum / arsenic ternary semiconductor laser (output 5 mW, oscillation wavelength 780 nm) was used as a light source. The results are shown below.

V ₀ : -715V V ₁ : -708V E _1/5 : 2.3 μJ / cm ²

Next, a photoconductor was prepared in the same manner as the above electrophotographic photoreceptor on a laser beam printer (LBP-CX manufactured by Canon Inc.) which is an electrophotographic printer of the reversal development system equipped with the semiconductor laser. A drum was mounted and an actual image forming test was conducted. The image forming conditions are as follows.

Surface potential after primary charging: −700 V Surface potential after image exposure: −150 V (exposure amount 0.8 μJ /
cm ² ) Transfer potential: +700 V Development polarity: Negative polarity Process speed: 50 mm / sec Development condition (development bias): -450 V Scan method after image exposure: Image scan Pre-charging pre-exposure: 40 lux / second red full surface exposure

Image formation was performed by line scanning the laser beam in accordance with the character signal and (graphic) signal.
Good prints were obtained for both letters and (graphics). Furthermore,
When the continuous printing of 5000 sheets was performed, 50 from the beginning
A stable print was obtained up to 00 sheets.

Example 12 An electrophotographic photosensitive member was prepared in the same manner as in Example 11 except that the compound having the following structure was used as the charge generating substance.

[0080]

[Outside 15]

The electrophotographic photosensitive member thus obtained was evaluated in the same manner as in Example 11. The results are shown below.

V ₀ : −715V V ₁ : −710V E _1/5 : 1.2 μJ / cm ²

Also in the image forming test, as in Example 11, stable printing was obtained from the initial stage to 5000 sheets.

[0084]

EFFECT OF THE INVENTION The electrophotographic photoreceptor of the present invention does not cause cracks in the charge transport layer even if it is not used for a long period of time.
Further, the electrophotographic photosensitive member of the present invention has good sensitivity, stable electrophotographic characteristics even after repeated use, and a small increase in residual potential. Therefore, according to the present invention, a defect-free image can be obtained, and the quality of the image is less likely to deteriorate even if the image formation is repeated.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of an electrophotographic apparatus using an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 1 Electrophotographic Photoreceptor 3 Primary Charging Means 4 Image Exposure 5 Developing Means 6 Transfer Means 9 Cleaning Means 11 Process Cartridge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Nakata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (7)

[Claims] 1. An electrophotography comprising a support and a photosensitive layer formed on the support, wherein the photosensitive layer contains an arylamine compound represented by the following general formula (1). Photoconductor. [Outside 1] In the general formula (1), R ₁ represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aromatic hydrocarbon ring group which may have a substituent. R ₂ -R ₈
Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an amino group which may have a substituent. Ar represents an alkyl group which may have a substituent, an aromatic hydrocarbon ring group which may have a substituent or an aromatic heterocyclic group which may have a substituent. 2. The electrophotographic photosensitive member according to claim 1, wherein the aromatic hydrocarbon ring group represented by R ₁ in the general formula (1) is a phenyl group having an alkyl group. 3. The electrophotographic photosensitive member according to claim 2, wherein the alkyl group is in a para position with respect to a nitrogen atom. 4. The electrophotographic photosensitive member according to claim 3, wherein the alkyl group is a methyl group. 5. The electrophotographic photosensitive member according to claim 1, wherein titanyl phthalyl phthalocyanine having the following structure is contained in the photosensitive layer as a charge generating substance. [Outside 2] 6. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and an image exposure for performing an image exposure on the charged electrophotographic photosensitive member to form an electrostatic latent image. An electrophotographic apparatus comprising means and developing means for developing the electrophotographic photosensitive member on which an electrostatic latent image is formed with toner. 7. A process cartridge comprising at least one of a charging means, a developing means, and a cleaning means, together with the electrophotographic photosensitive member according to claim 1.