JP2001242647A - Electrophotographic photoreceptor and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrophotographic photoreceptor by using a solvent for the coating liquid for a charge transfer layer, the solvent which does not cause environmental problems because it does not enlarge ozone hole or it is not toxic such as carcinogenic, which does not cause failure such as brushing during coating because the solvent has high dissolving power and a proper boiling point, and which does not give adverse influences on the electrophotographic characteristics, and to provide an electrophotographic photoreceptor manufactured by this method. SOLUTION: The electrophotographic photoreceptor features that a dioxolane compound and hydrocarbon compound are mixed and used as the solvent for the coating liquid for the charge transfer layer.

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 and a method for manufacturing the same.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors include inorganic photoreceptors using conventionally used selenium and cadmium sulfide, and the like.
A considerable period has passed since the transition to organic photoreceptors began. Recently, some amorphous silicon materials have been developed, but most of the electrophotographic photoconductors are organic photoconductors.

This is because organic materials have been widely developed, and it has become possible to produce photoconductors having various performances. Therefore, it has become possible to develop an organic photoreceptor having various characteristics as an electrophotographic photoreceptor while responding to environmental problems and efficiency in manufacturing at present.

[0004] Among them, one of the problems still remaining is the selection of a solvent for the coating solution for the charge transport layer. For example, some halogen-based compounds have excellent properties as a solvent for the charge transport layer, but they are harmful, and it is difficult to find a compound having a high solubility and a proper boiling point suitable for industrial production.

Japanese Patent Application Laid-Open No. Hei 10-207090 discloses a technique using non-halogen tetrahydrofuran (THF), dioxane and toluene as a solvent for a coating solution for a charge transport layer, but THF has a low flash point. It is dangerous and it is said that dioxane has a carcinogenic problem.

As described above, as a solvent for the coating solution for the charge transport layer of the electrophotographic photoreceptor, there is no toxicity such as ozone hole expansion and carcinogenicity, unlike a halogen-based compound. Since it has a high boiling point and an appropriate boiling point, no solvent has been found that does not cause troubles such as brushing during coating and does not adversely affect the electrophotographic properties.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide no toxicity such as expansion of ozone hole and carcinogenicity, so that it does not cause environmental problems, has a high dissolving power and has a proper boiling point. Provided is a method of manufacturing an electrophotographic photosensitive member using a solvent for a charge transport layer coating solution that does not cause a failure such as brushing and does not adversely affect electrophotographic characteristics, and an electrophotographic photosensitive member manufactured thereby. It is in.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that dioxolane compounds have excellent properties,
Although there is no environmental problem such as toxicity, brushing is liable to occur in the step of drying after applying the coating solution for the charge transport layer. However, it has been found that the addition of a hydrocarbon compound can suppress this, and furthermore, the coating film thickness can be made more uniform, and the present invention has been achieved.

[1] An electrophotographic photoreceptor comprising a mixture of at least two of a dioxolane compound and a hydrocarbon compound as a solvent used in a charge transport layer coating solution.

[2] The electrophotographic photosensitive member according to [1], wherein the hydrocarbon compound is toluene.

[3] The viscosity of the charge transport layer coating solution is 0.0
The electrophotographic photosensitive member according to [1], wherein the pressure is 30 to 1.500 Pa · s.

[4] A method for producing an electrophotographic photosensitive member, characterized in that a dioxolane-based compound and a hydrocarbon-based compound are mixed and used as a solvent for a charge transport layer coating solution.

In the case of an electrophotographic photoreceptor, in particular, in the case of an organic photoreceptor, in order to form a photosensitive layer and a photosensitive auxiliary layer, the best method is to dissolve the compounds constituting them and apply them.

However, coating solvents for the electrophotographic photoreceptor layer which have been widely used in the past are organic solvents of halogen-containing elements such as methylene chloride, ethylene chloride, chloroform, monochlorobenzene and the like.
From the viewpoint of carcinogenicity and the like, the use is being restricted.

As the organic solvent containing no halogen, toluene, tetrahydrofuran (THF), dioxane, methyl ethyl ketone (MEK), cyclohexane and the like have been used. In addition, problems such as insufficient coating film thickness due to the inability to increase the concentration of the coating solution cannot be solved. In particular, in the case of a charge transporting layer, a film thickness of 12 μm or more is required. For example, when polycarbonate is used as a binder, a coating solution having a high concentration of at least 5% by mass or more, preferably 8% by mass or more is used. .3Pa · S
(22 ° C.) or less. However, such characteristics cannot be obtained with the above-mentioned organic solvent containing no halogen.
In some cases, it is necessary to adopt a method of applying the composition in different times.

As will be described later, polycarbonate is often used as an excellent binder in a photosensitive layer of an electrophotographic photosensitive member, particularly in a charge transport layer. As a good solvent that does not contain halogens of polycarbonate, it has 2 oxygen atoms in the molecule.
There is dioxane, a cyclic ether containing dioxane, but dioxane is highly toxic and carcinogenic and cannot be put into the manufacturing process.

The dioxolane compound of the present invention is a cyclic 5-membered ether compound having a dioxolane nucleus containing two non-adjacent oxygen atoms in a molecule. Among them, the dioxolane derivative according to the present invention has a dioxolane nucleus in the molecular structure, dissolves a binder or other additives used for the photoreceptor, and if the photoreceptor is manufactured, it may be any one that can be dried. Normally boiling point 200
C. or lower is used.

In the present invention, the dioxolane compound is
Specifically, those represented by the following general formula (1) are preferably used.

[0019]

Embedded image

In the formula, R _{1 to} R ₆ represent a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms. Also, R ₅
And at least two groups of R ₆ or R _{1 to} R ₄ may be bonded to form a ring.

The substituent of the alkyl group may be any one, but preferably an alkoxy group having 1 to 4 carbon atoms, an acyl group, an acyloxy group or a hydroxyl group. The ring formed by combining R ₅ and R ₆ , or at least two of R _{1 to} R ₄ , may be any, but is preferably a 5- to 6-membered aromatic ring (for example, benzene Ring) or a non-aromatic ring (for example, a cyclohexane ring).

Of these, those in which at least one of R ₅ and R ₆ is a hydrogen atom, or those in which R ₁ and R ₃ are hydrogen atoms are preferred, and all of R _{1 to} R ₆ are hydrogen atoms. Are particularly preferred.

The compound of the present invention has a boiling point of 2 at normal pressure.
It is preferable that the temperature is not higher than 00 ° C, but the lower limit is not lower than 74 ° C. Those having a boiling point of 150 ° C or lower are more preferred, and those having a boiling point of 74 to 130 ° C are particularly preferred.

The reason for this is that if the boiling point is high, the drying step is lengthened, which is disadvantageous in terms of cost.
If it is higher, it is practically disadvantageous.

Specific examples of the compounds which can be preferably used in the present invention are shown below, but some of them may be used in combination.

[0026]

Embedded image

[0027]

Embedded image

[0028]

Embedded image

[0029]

Embedded image

On the other hand, hydrocarbon compounds are typically toluene, xylene, heptane and the like. Generally, those having about 5 to 10 carbon atoms and a boiling point of 70 to 150 ° C. are preferable, but a mixture of several kinds may be used. It is better that the boiling point is slightly higher than that of the dioxolane compound to be mixed, and toluene is particularly preferable.

It is necessary to use at least one kind of the dioxolane compound and at least one kind of the hydrocarbon compound. Any one of the dioxolane compounds and the plurality of hydrocarbon compounds may be used. Further, other solvents may be mixed and used as long as the effects of the present invention are not significantly impaired.

The mixing ratio of the dioxolane compound and the hydrocarbon compound used in the mixture is 90 to 30/10 to 7 by the mass ratio of dioxolane compound / hydrocarbon compound.
0 is preferred. Further, the ratio is preferably from 85 to 40/15 to 60.

The reason why a mixed solvent obtained by adding a hydrocarbon compound to these dioxolane compounds exhibits a remarkable effect of preventing brushing of the coating layer and uniforming the film thickness is not completely clarified.

It is presumed that the dioxolane compound has a large latent heat of vaporization and has a high affinity for water. Therefore, if it is used alone, the temperature tends to decrease locally during drying. This causes brushing and non-uniform film thickness. However, the addition of the hydrocarbon-based compound slightly reduces the drying speed, and as a result, the above-mentioned failure will not be eliminated.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The binder for the charge transport layer preferably used in the present invention includes polycarbonate, polyester polycarbonate, polyester, polyurethane, polystyrene, polystyrene copolymer, polysiloxane, polyacrylate and polyacrylate copolymer. Coalesce, phenoxy resin, ABS resin, polyvinyl chloride, polyvinyl chloride copolymer, polyvinyl acetate copolymer,
Examples include polyvinyl formal and polyvinyl butyral.

Among them, polycarbonate-based ones are more preferable, and for example, bisphenol A-type polycarbonate (BPA), bisphenol Z-type polycarbonate, or the following polycarbonates are preferable. That is, those described in p5 to p7 of JP-A-3-171506, those described in p5 to p7 of JP-A-5-113670,
P87-p29, p36-p41, p of -87119
52-p57, p61-p63; Si element-containing polycarbonate described in JP-A-3-45958; F atom-containing polycarbonate described in JP-A-5-188628; polycarbonate described in JP-A-4-179996; Polycarbonates described in p6 to p13 of Kaihei 7-13361, p9 to p9 of JP-A-8-272125.
Polycarbonate described in p14.

Further, it is also preferable to include a silicone oil in the coating composition for a photoreceptor of the present invention from the viewpoint of improving coating properties.

As the silicone oil, Japanese Patent O.P.I.
No. 143643, JP-A-57-5050, JP-A-57-50
And silicone oils described in JP-A-212453, JP-A-59-208556, JP-A-63-80262, JP-A-1-234854, JP-A-4-199154 and JP-A-5-27456. In particular, methylphenyl silicone oil and dimethyl silicone oil are preferable, and the content of the contained layer in the solid content is preferably 10 to 1000 ppm.

Next, as the conductive support for supporting the photosensitive layer, a metal plate or metal drum of aluminum, nickel, or the like, a plastic film on which aluminum, tin oxide, indium oxide, or the like is deposited, or a conductive material is applied. Paper, plastic film and drums can be used.

When an undercoat layer is provided, a resin-based undercoat layer using a polyamide compound such as nylon, or a so-called ceramic undercoat layer using an organometallic compound and a silane coupling agent (curable undercoat layer) Layer)
Is preferably used.

The formation of the photosensitive layer is carried out by using an organic photoconductive layer, particularly a function-separated type containing both a charge transport material and a charge generation material.
In particular, it is preferable that each is formed as a separate layer and formed by multi-layer coating.

The charge generation layer is formed by dispersing a charge generation material (CGM) in a binder resin as required.
Examples of the CGM include metal or metal-free phthalocyanine compounds, bisazo compounds, azo compounds such as trisazo compounds, squarium compounds, azurenium compounds, perylene compounds, indico compounds, quinacridone compounds,
Polycyclic quinone compounds, cyanine dyes, xanthene dyes,
Examples include, but are not limited to, charge transfer complexes comprising poly-N-vinylcarbazole and trinitrofluorenone. These may be used as a mixture of two or more as necessary.

However, in order to achieve the object of the present invention at the highest level, one of perylene compounds, imidazole perylene compound or metal phthalocyanine compound such as titanyl phthalocyanine (TiOPc), gallium phthalocyanine (GaPc), or hydroxygallium phthalocyanine. (GaOHPc) and the like are preferable.

As the binder usable for the charge generation layer, for example, polystyrene resin, polyethylene resin,
Polypropylene resin, polyacrylic resin, polymethacrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinyl butyral resin, polyepoxy resin, polyurethane resin, polyphenol resin, polyester resin, polyalkyd resin, polycarbonate resin, polysilicone resin, Polymelamine resins, and copolymer resins containing two or more of the repeating units of these resins, such as vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, and polymers Examples include, but are not limited to, organic semiconductors, such as poly-N-vinyl carbazole.

Among the above, when an imidazole perylene compound is used as CGM, preferred binders include:
Polyvinyl butyral resin is exemplified. When TiOPc is used, a preferable binder is, for example, a combination of a polysilicone resin and a polyvinyl butyral resin, or a mixture of both a polysilicone resin and a polyvinyl butyral resin.

The charge transport layer is composed of a charge transport material (CTM) alone or together with a binder resin. CT
As M, for example, a carbazole derivative, an oxazole derivative, an oxadiazole derivative, a thiazole derivative,
Thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, pyrazoline derivative, oxazolone derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, amino Stilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like, but are not limited thereto. Absent. These may be used alone or in combination of two or more.

As the binder resin usable for the charge transport layer, as described above, for example, a polycarbonate resin, a polyacrylate resin, a polyester resin, a polystyrene resin, a styrene-acrylonitrile copolymer resin, a polymethacrylate resin, Examples include, but are not limited to, styrene-methacrylate copolymer resins. In addition, in order to reduce fatigue deterioration upon repeated use or to improve durability, any known antioxidant, electron-accepting substance, surface modifier, plasticizer, etc. may be used in each layer of the photoreceptor. And an environment-dependent reducing agent, if necessary, in an appropriate amount.

Further, in order to improve the durability, a non-photosensitive layer (auxiliary layer) such as a protective layer may be provided in addition to the photosensitive layer, if necessary. A photoconductor having a so-called multilayer charge transport layer may be used.

Further, a dye for correcting color sensitivity may be added to the photoreceptor of the present invention. The configuration of the photoreceptor in the present invention is desirably a stacked type photoreceptor with the charge generation layer facing down and the charge transport layer facing up, but the effects of the present invention are not limited to such a configuration and may vary. It is exhibited in the form of FIGS. 1A to 1F show typical configurations.

In the case of FIG. 1A, a charge generation layer 2 is formed on a conductive support 1, and a charge transport layer 3 is laminated thereon to form a photosensitive layer 4, and FIG. The photosensitive layer 4 is formed by reversing the charge generation layer 2 and the charge transport layer 3. (C) shows that the undercoat layer 5 is provided between the photosensitive layer 4 having the layer configuration of (a) and the conductive support 1, and (d)
In the (b) layer structure, an undercoat layer 5 is provided between the photosensitive layer 4 and the conductive support 1. (E) shows a photosensitive layer 4 'containing a charge generating substance and a charge transporting substance, and (f) shows an undercoat layer 5 between such a photosensitive layer 4' and the conductive support 1. Is provided. (A)
In the structures of (f) to (f), a protective layer can be further provided on the outermost layer.

As a method for applying the photosensitive layer and its auxiliary layer, there are various methods such as a dipping method (dipping method), a spray method, a blade method, and a slide hopper method. It is preferable to apply by using a quantity-regulated coating method (apparatus). These techniques are described in JP-A-58-189061, JP-A-8-3906.
18209 or JP-A-9-10654.

Next, an image forming apparatus which can be used in the image forming method and the image forming apparatus of the present invention will be described.

In the image forming apparatus shown in FIG. 2, although not shown in the figure, light from a light source is applied to an original, the reflected light is converted into an electric signal by an image reading section, and this image data is converted into an image writing section 101. To 103. In addition, 1
01 is an exposure light source, 102 is a polygon mirror, 103 is f
It is an optical image correction lens such as a θ lens.

At the time of image formation, the photosensitive drum 104 rotating in the direction of the arrow is charged by the uniform charger 105 and charged. The image is exposed to the image by the image writing unit to form an electrostatic latent image. The developed image on the photoconductor drum is transferred by a transfer pole (transfer unit) 107 onto a recording material 108 sent out in a timely manner, and the recording material 108 is separated from the photoconductor by a separation pole (separator) 109. , To the fixing device 110.

After the separation, the photosensitive drum 104 is removed by a cleaning device (cleaning device) 111 to remove toner and the like remaining without being transferred, and passes through a pre-charging exposure lamp (PCL) 112 again to form the next image. It is charged by the uniform charger 105.

The developing system used in the present invention is preferably a reversal developing system, and the cleaning device is preferably a system using an elastic rubber blade (113 in FIG. 2) such as urethane rubber or silicone rubber.

The transfer member is usually plain paper, but may be PET for an overhead projector (OHP).
Broadly includes those that can be transferred, such as bases.

Further, as the original information of the image formation, in addition to the above, the image information can be stored in advance in an image memory such as a ROM or a floppy disk, and the information in the image memory can be taken out and output to the image forming section as required. it can. Therefore, an image forming apparatus according to the present invention includes a device that does not have an image reading unit but stores information from a computer or the like in a memory and outputs the information to an image forming unit as in this example. The most common of these are an LED printer and an LBP (laser beam printer).

[0059]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

1. Preparation of Photoconductor Example 1 As a conductive support, a mirror-finished diameter of 80 mm was used.
An aluminum drum substrate having a height of 355 mm was used.

The following undercoat layer coating solution was prepared on the support and coated so as to have a dry film thickness of 1.0 μm.

Undercoat Layer Coating Solution Titanium chelate compound (TC-750, manufactured by Matsumoto Pharmaceutical Co., Ltd.) 30 g Silane coupling agent (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) 17 g 2-propanol 150 ml On the undercoat layer, apply the following charge generation layer The liquid was dispersed and prepared, and dip-coated so as to have a thickness of 0.5 μm.

Charge Generating Layer Coating Solution Y-type titanyl phthalocyanine (CGM-1) 10 g Silicone resin (KR-5240 manufactured by Shin-Etsu Chemical Co., Ltd.) 10 g-t-butyl acetate 1000 ml A dispersion of the above coating solution using a sand mill for 20 hours.

The following charge transport layer coating solution was prepared on the charge generation layer, dip-coated to a dry film thickness of 23 μm, and dried at 105 ° C. for 80 minutes to obtain a photoreceptor.

Charge transport layer coating liquid Charge transportable substance (CTM-1) 500 g Polycarbonate (Iupilon Z200 manufactured by Mitsubishi Gas Chemical Company) 560 g Dioxolane (Compound Example No. 1) 1960 ml Toluene 840 ml Methylphenyl silicone oil (KF-54 Shin-Etsu Chemical) 100 ppm based on the total solid content

[0066]

Embedded image

[0067]

Embedded image

Example 2 A conductive support, an undercoat layer and a charge generation layer were prepared in the same manner as in Example 1, and the charge transport layer was prepared by preparing the following charge transport layer coating solution and having a dry film thickness of 23 μm. After dip coating,
The photosensitive member was obtained by drying at 105 ° C. for 80 minutes.

Charge transporting substance (CTM-1) 500 g Polycarbonate (Iupilon Z200 manufactured by Mitsubishi Gas Chemical Company) 560 g Dioxolane (Compound Example No. 5) 1960 ml Toluene 840 ml Methylphenyl silicone oil (KF-54 Shin-Etsu Chemical Co., Ltd.) All solids Example 3 The same conductive support as in Example 1 was used, and the following undercoat layer coating solution was prepared and dip-coated to a dry film thickness of 1.0 μm.

Undercoat Layer Coating Solution Copolymer Nylon Resin (CM-8000, manufactured by Toray Industries, Ltd.) 2.0 g Methanol / n-butanol (10/1 volume ratio) 1000 ml On this undercoat layer, the following charge generation layer coating solution was coated. The dispersion was prepared and dip coated to a thickness of 0.5 μm.

Charge Generating Layer Coating Solution Perylene Pigment (CGM-2) 50 g Butyral Resin (Eslek BX-L, manufactured by Sekisui Chemical Co., Ltd.) 50 g Methyl Ethyl Ketone 1000 ml The following charge transport layer coating solution was prepared on this charge generating layer.
After dip coating to a dry film thickness of 23 μm,
It dried at 80 degreeC and 80 minutes, and obtained the photoreceptor.

Charge transport layer coating liquid Charge transportable substance (CTM-2) 500 g Polycarbonate (Iupilon Z200 manufactured by Mitsubishi Gas Chemical Company) 560 g Dioxolane (Compound Example No. 1) 1400 ml Toluene 1400 ml Methylphenyl silicone oil (KF-54 Shin-Etsu Chemical) Example 4 A conductive support, an undercoat layer, and a charge generation layer were prepared in the same manner as in Example 3, and the charge transport layer was prepared by using the following charge transport layer coating solution. After dip coating to a dry film thickness of 23 μm,
The photosensitive member was obtained by drying at 105 ° C. for 80 minutes.

Charge transport layer coating solution Charge transportable substance (CTM-2) 500 g Polycarbonate (Iupilon Z200 manufactured by Mitsubishi Gas Chemical Company) 560 g Dioxolane (Compound Example No. 5) 1400 ml Toluene 1400 ml Methylphenyl silicone oil (KF-54 Shin-Etsu Chemical) Comparative Example 1 In Example 1, dioxolane (Compound Example No. 1) was used alone as the solvent for the charge transport layer coating solution.

Comparative Example 2 In Example 3, dioxolane (Compound No. 5) alone was used as the solvent for the coating solution for the charge transport layer.

Comparative Example 3 In Example 4, the solvent of the charge transport layer coating solution was methylene chloride.

2. Performance Evaluation The applicability (appearance, film thickness and deviation) of the photoreceptor produced as described above and the electrophotographic characteristics (potential characteristics) were evaluated using an analog copying machine U-BIX 4045 (manufactured by Konica Corporation). .

1) Coatability Appearance: The surface condition of the photoreceptor after coating and drying was visually observed.

Film thickness and deviation: The thickness of the photosensitive member was 2.0 cm from the end of the effective photosensitive layer at both the upper end and the lower end when the photosensitive member was coated.
The position at the center was measured at five points along the circumference of the substrate, and an average value and a deviation from the average value were obtained.

[0079]

[Table 1]

2) Electrophotographic Characteristics The above copying machine was modified and equipped with a surface potentiometer, and the 100th (after 100C) potential (−V) was measured when the process of charging → exposure → discharge was repeated 100 times. Was evaluated.

Vb: Potential (-V) of the black image portion Vg: Potential (-V) of the gray image portion (density = 0.20) Vw: Potential (-V) of the white image portion Vr: After completion of the process Residual potential (-V)

[0082]

[Table 2]

As in Examples 1 to 4 in the present invention, the electrophotographic photoreceptor using the solvent used in the coating solution for the charge transport layer in which the dioxolane compound and the hydrocarbon compound are mixed is not affected by brushing and other troubles. It does not occur, and does not adversely affect the electrophotographic characteristics.

[0084]

According to the present invention, since there is no toxicity such as expansion of ozone hole and carcinogenicity, there is no environmental problem, the dissolving power is high, and since it has a proper boiling point, troubles such as brushing during coating can be prevented. It is possible to provide a method for producing an electrophotographic photosensitive member using a solvent for a coating liquid for a charge transport layer which does not cause adverse effects on electrophotographic characteristics and an electrophotographic photosensitive member produced by the method.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a photoconductor according to the present invention.

FIG. 2 is a schematic sectional view of the image forming apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 charge generation layer 3 charge transport layer 4 photosensitive layer 4 ′ photosensitive layer containing charge generation substance and charge transport substance 5 undercoat layer 101 exposure light source 102 polygon mirror 103 optical image correction lens 104 such as fθ lens 104 photosensitive Body drum 106 Developing device (reversal development method) 113 Elastic rubber blade

Claims (4)

[Claims] 1. An electrophotographic photoreceptor comprising a mixture of at least two of a dioxolane compound and a hydrocarbon compound as a solvent used in a charge transport layer coating solution. 2. The electrophotographic photosensitive member according to claim 1, wherein the hydrocarbon compound is toluene. 3. The charge transport layer coating solution has a viscosity of 0.030 to 0.030.
2. The electrophotographic photoreceptor according to claim 1, wherein the pressure is 1.500 Pa.s. 4. A method for producing an electrophotographic photoreceptor, wherein a solvent used in the coating solution for the charge transport layer is a mixture of a dioxolane compound and a hydrocarbon compound.