JP2002303995A - Method for producing coating liquid for charge moving layer for electrophotographic sensitive body and electrophotographic photoreceptor and image forming device both using the coating liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a uniform coating liquid for a charge moving layer excellent in electrophotographic characteristic by preventing the coating liquid for the charge moving layer from gelling, and to provide a homogeneous electrophotographic photoreceptor and an image forming device both using the coating liquid. SOLUTION: This method for producing coating liquid for a charge moving layer includes a stage in which the coating liquid for the charge moving layer is held for a fixed time under the temperature of 10 deg.C to 45 deg.C in inert atmosphere after it is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coating solution for a charge transfer layer for an electrophotographic photoreceptor, which exhibits favorable electric characteristics when maintained under a specific condition. The present invention relates to an electrophotographic photosensitive member having a charge transfer layer formed by using a coating solution for a transfer layer, and an image forming apparatus such as a copying machine, a printer, a facsimile or the like equipped with the photosensitive member.

[0002]

2. Description of the Related Art Generally, an electrophotographic photosensitive member is formed by providing a photosensitive layer on a conductive support such as aluminum. There are various types of photosensitive layers, and a charge generation layer and a charge transfer layer (also referred to as a "charge transport layer") on a conductive support. In the present invention, the charge transfer layer is hereinafter referred to as a "charge transfer layer". ) Are generally formed in this order. Among these, the charge transfer layer is a layer that plays an important role of transferring the charges generated in the charge generation layer to the surface of the photoreceptor,
The characteristics of the charge transfer layer greatly affect the image formation by the electrophotographic method.

The above-mentioned charge transfer layer is applied by a known coating method such as dip coating or spray coating. Conventionally, the charge transfer layer has been applied immediately after adjusting the coating solution.
In addition, even when the coating was performed after the holding for a certain period, no particular attention was paid to the holding environment.

[0004]

However, there is a problem that the coating solution for the charge transfer layer is apt to gel. When the coating solution for the charge transfer layer gels, not only does the yield deteriorate,
There is a problem that the uniformity of the coating liquid cannot be maintained, and the produced electrophotographic photosensitive member and the image forming apparatus vary. In addition, the coating solution for the charge transfer layer immediately after the adjustment has a problem that the state of the coating solution is not stable, and the electric characteristics vary from application to application. The present invention solves the above problems, and provides a coating solution for a charge transfer layer which is uniform and excellent in electrophotographic characteristics, and provides a uniform electrophotographic photosensitive member and an image forming apparatus using the same. It is in.

[0005]

The object of the present invention is to prepare a coating solution for a charge transfer layer comprising at least a charge transfer material, a binder resin and a solvent, and then prepare the coating solution at 10 ° C. in an inert atmosphere.
The method comprises a step of maintaining the coating at a temperature of from 45 ° C. to 45 ° C. for a certain period of time.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electrophotographic photosensitive member manufactured according to the present invention will be described below. Examples of the electrophotographic photosensitive member include a cylindrical electrophotographic photosensitive member having a photosensitive layer formed on a conductive support such as a cylindrical aluminum substrate, and a sheet in which aluminum is vapor-deposited on a flexible plastic sheet. There is a sheet-like electrophotographic photosensitive member in which a photosensitive layer or the like is formed on a conductive support having a shape of a sheet. Hereinafter, the present invention will be described based on an electrophotographic photosensitive member using a conductive support such as a cylindrical aluminum substrate, but the present invention is not limited to this.

As described above, an electrophotographic photosensitive member generally has a photosensitive layer including a charge generation layer and a charge transfer layer provided on a conductive support. The photosensitive layer may be of a laminated type or a single layer type, but the laminated type is particularly preferably used.
In the laminated photosensitive layer, a charge generation layer containing a charge generation substance and a charge transfer layer containing a charge transfer substance provided thereon are formed, and a surface layer may be further provided thereon. .

The conductive support of the electrophotographic photosensitive member used in the present invention is not particularly limited, but aluminum or an aluminum alloy is preferably used. As the material of the aluminum conductive support, for example, JIS1050, JIS1070, JIS108
0 or other pure aluminum or AL-Mg alloy, AL
-Various aluminum alloys such as a Cu-based alloy, an AL-Si-based alloy, an AL-Mg-Si-based alloy, and an AL-Cu-Si-based alloy, and more preferably JIS 3003, which is an AL-Mn-based alloy. JIS60 which is a Si alloy
63 and the like. In the present invention, the term “aluminum” generally indicates a general term including an aluminum alloy, unless otherwise indicated.

The method of producing these aluminum conductive supports is not particularly limited, but an aluminum billet is formed into an extruded tube by a porthole method, a mandrel method, or the like, and then formed into a cylinder having a predetermined thickness and outer diameter. Therefore, it can be made by performing mirror finishing by drawing, impact, ironing, or cutting. Since a drawing oil, a cutting oil, a rust-preventive oil, various dusts in the air, and the like are attached to the surface of the conductive support, a cleaning treatment is usually performed before the photosensitive layer is formed.

The diameter (φ mm described later) of the conductive support is manufactured according to an image forming apparatus using an electrophotographic photosensitive drum, but is preferably 5 mm to 500 mm.
Usually, 10 mm to 200 mm is more preferable.

[0011] The conductive support may be provided with a known anodic oxide coating. Such an anodized film can be provided by a commonly used anodizing method.

Further, a known undercoat layer may be provided on the conductive support. The undercoat layer is composed of at least inorganic particles and a binder resin.

Examples of the binder resin for the undercoat layer include polyvinyl acetal such as polyvinyl butyral, cellulose, and the like.
Thermoplastic resins such as polyamide, epoxy, urethane, acrylic acid, and methacrylic acid, or thermosetting resins, and photocurable resins include, but are not limited to, adhesion to a conductive support, solvent resistance, electrical barrier properties, Alcohol-soluble resins are preferred from the viewpoint of coating properties and drying properties, and alcohol-soluble polyamide resins are particularly preferred. Among them, a copolymerized polyamide resin having a diamine component as a constituent component is particularly preferable in terms of performance as an undercoat layer, stability of a coating solution, and adhesiveness between the undercoat layer and the conductive support.

The inorganic particles are added to satisfy the required properties of the undercoat layer. Examples of the inorganic particles include inorganic particles such as a metal oxide. In particular, metal oxides that have been subjected to surface treatment for hydrophobization are preferred. The hydrophobic treatment is performed by a known method.

Further, the undercoat layer coating liquid may contain various surfactants for the purpose of improving coatability and dispersibility of dispersed particles. In addition, it may contain a leveling agent and an antioxidant.

The undercoat layer coating solution can be adjusted as follows. The metal oxide particles that have been hydrophobized with an organic compound are subjected to a dispersion treatment using a ball mill, a co-ball mill, a sand mill, or the like, and then diluted to an appropriate concentration to prepare a slurry. A binder resin solution previously dissolved in a solvent is added to the slurry and mixed to prepare an undercoat layer coating solution. Alternatively, binder resin pellets and powder are directly added to the slurry, mixed and stirred, and the binder resin is dissolved to prepare an undercoat layer coating solution. Conversely, it can also be adjusted by adding metal oxide particles treated with an organic compound to the binder resin solution and performing the above dispersion treatment. In these manufacturing processes, various additives can be arbitrarily added. If necessary, a heat treatment, an ultrasonic treatment, or the like may be added.

The undercoat layer coating solution thus obtained is coated on a conductive support and dried to form an undercoat layer. Spray coating, nozzle coating, blade coating, spin coating,
Any method such as dip coating may be used, and among them, dip coating is particularly preferable. A photosensitive layer is formed on the undercoat layer.

The thickness of the undercoat layer is 0.1 μm to 20 μm,
Preferably 0.3 μm to 10 μm, more preferably,
It is more preferably from 0.5 μm to 5 μm, and particularly preferably from 1 μm to 2 μm.

Next, the charge generation layer contains at least a charge generation substance and a binder resin, and the coating solution for the charge generation layer comprises a charge generation agent, a binder and a solvent.

The charge generating material is not particularly limited as long as it is used for an electrophotographic photosensitive member.
Specifically, selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, other inorganic photoconductors, phthalocyanines, azo, quinacridone, polycyclic quinone,
Organic pigments such as perylene-based, indigo-based, squarylium-based, azulenium-based, thiapyrylium-based, and benzimidazole-based pigments can be used. Especially copper,
Metals such as indium chloride, potassium chloride, tin, oxytitanium, zinc, and vanadium, or phthalocyanines coordinated with oxides or chlorides thereof, metal-free phthalocyanines, or azo such as monoazo, bisazo, trisazo, and polyazos Pigments are preferred. Of these, azo pigments or phthalocyanines are more preferable, oxytitanium phthalocyanine is more preferable, and so-called Y-type oxytitanium phthalocyanine is particularly preferable because high sensitivity can be obtained. The charge generating substance may be used alone or in combination of two or more. For example, a mixture of a so-called Y-type oxytitanium phthalocyanine and a so-called β-type oxytitanium phthalocyanine or α-type oxytitanium phthalocyanine may be used as the charge generating substance.

The so-called Y-type oxytitanium phthalocyanine has a maximum diffraction peak at a Bragg angle (2θ ± 0.2) of 27.3 ° in X-ray diffraction by CuKα ray. This crystalline oxytitanium phthalocyanine is generally referred to as Y-type or D-type. For example, FIG. 2 of JP-A-62-67094 (referred to as II-type in the same publication), JP-A-2-82
FIG. 1 of JP-A No. 56, FIG. 1 of JP-A-64-82045, Journal of the Institute of Electrophotographic Engineers, Vol. 92 (issued in 1990), No. 3, pp. 250-258. Are shown). This crystalline oxytitanium phthalocyanine is characterized in that it exhibits a maximum diffraction peak at 27.3 °.
Peaks are shown at 9.7 ° and 24.2 °.

The intensity of the diffraction peak may vary depending on the crystallinity, the orientation of the sample, and the measuring method.
The Y-type oxytitanium phthalocyanine has a maximum diffraction peak at 27.3 ° as measured by the blendano concentration method. When measured by a thin film optical system (generally called a thin film method or a parallel method), the maximum diffraction peak may not be 27.3 ° depending on the state of the sample. It is considered that they are oriented in the direction.

The binder resin is not particularly limited as long as it is generally used for the charge generation layer of the electrophotographic photoreceptor. , Polyester carbonate, polysulfone, polyimide, polymethyl methacrylate, phenolic resin, butyral resin, vinyl polymers such as polyvinyl chloride, and copolymers thereof, phenoxy, epoxy,
A silicone resin or the like or a partially crosslinked cured product thereof can be used alone or in combination of two or more.

Various solvents can be used as a solvent for dispersing the above-mentioned charge generating substance and the binder resin. For example, ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran and 1,2-dimethoxyethane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; alcohols such as methanol, ethanol and propanol alone. Alternatively, two or more kinds can be used as a mixture.

The amount of the solvent to be used may be any amount as long as dispersion can be sufficiently performed and an effective amount of the charge generating agent is contained in the coating solution. Usually, the concentration of the charge generating agent in the coating solution at the time of dispersion is determined. 3 to 20 wt%, more preferably 4 to 20 wt%
% Is preferred.

As a method of mixing the binder resin and the charge generating substance, for example, a method of dispersing the charge generating substance while the binder resin is in a powder state, or adding a solution of the binder resin and simultaneously dispersing the powder, Any method such as a method of mixing a dispersion liquid comprising a substance and a solvent into a binder resin solution, or a method of mixing a binder resin solution into such a dispersion liquid may be used.

Next, the coating liquid obtained here may be diluted with various solvents in order to make the liquid properties suitable for coating. As such a solvent, for example, the solvents exemplified as the dispersion medium can be used. The ratio between the charge generating substance and the binder resin is not particularly limited, but generally, 5 parts by weight of the charge generating substance with respect to 100 parts by weight of the resin.
It is used from the range of -500 parts by weight. The thickness of the charge generation layer is set at 0.
A range of 1 μm to 10 μm, and more preferably a range of 0.5 μm to 8 μm.

The charge transfer layer contains at least a charge transfer substance and a binder resin, and the coating solution for the charge transfer layer comprises at least a charge transfer substance, a binder resin and a solvent.

The charge transfer material is not particularly limited as long as it is a material usually used for a charge transfer layer of an electrophotographic photoreceptor, and specifically, 2,4,7-trinitrofluorenone , Electron-withdrawing substances such as tetracyanooxydimethane, heterocyclic compounds such as cerbazole, indole, imidazole, oxazole, pyrazole, oxadiazole, pyrazoline, thiadiazole,
An electron donating substance such as an aniline derivative, a hydrazone compound, an aromatic amine derivative, a stilbene derivative, or a polymer having a group consisting of these compounds in a main chain or a side chain is given.

For the charge transfer layer, the same binder resin or the like as the charge generation layer can be used. That is, specific examples of the binder resin include polyvinyl butyral, polyvinyl acetal, polyester, polycarbonate, polystyrene, polyester carbonate, polysulfone, polyamide, polyimide, polymethyl methacrylate, phenolic resin, butyral resin, and vinyl such as polyvinyl chloride. Polymers, copolymers thereof, phenoxy, epoxy, silicone resins, etc., and partially crosslinked cured products thereof can be used alone or in combination of two or more. Of these, polyamide or polycarbonate is preferred. The ratio of the charge transfer material to the binder resin is
It is preferable that the amount of the charge transfer material is adjusted in the range of 5 to 500 parts by weight based on 0 part by weight.

Various solvents can be used as the solvent used in the coating solution for the charge transfer layer. For example,
Ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran and 1,2-dimethoxyethane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; alcohols such as methanol, ethanol and propanol; toluene; ;
Dioxane or the like can be used alone or in combination of two or more.

The coating solution for a charge transfer layer of the present invention is prepared, for example, as follows. First, a charge transfer material and a binder resin are added to a solvent, and then a dispersion treatment is performed using a stirrer, a homogenizer, or the like to prepare a uniform charge transfer layer coating solution.
At that time, if necessary, an antioxidant, a sensitizer, a leveling agent and the like may be contained.

The coating solution for the charge transfer layer thus prepared is kept under an inert atmosphere. Holding under an inert atmosphere in the present invention means that the coating solution for the charge transfer layer is placed under an atmosphere such as not being oxidized,
There is no particular limitation as long as the coating liquid and the external air can be brought into contact with each other. Specific examples include sealing the coating solution using a sealed container made of metal or the like that does not affect the composition of the coating solution, and maintaining the coating solution in an inert gas atmosphere. When sealing in a sealed container, the coating solution may be poured into the container until the voids are completely eliminated to form an inert atmosphere, but if this is not possible, the interior of the container must be inerted beforehand. After the replacement with the gas, the coating solution is poured, and an inert gas may be formed in the void to form an inert atmosphere.In addition to the case where the gas in the container is replaced with the inert gas, When pouring the charge transfer layer coating solution, the voids may be filled with the coating solution vapor while discharging the air in the container to the outside of the container. The inert gas is not particularly limited as long as it can prevent oxidation, and includes noble gases such as helium and neon in addition to nitrogen, and these may be used as a mixture. In addition,
The pressure in the sealed container is not particularly limited,
0.8 to 3 atm is preferable, and 1 to 1.2 atm is particularly preferable.

The coating solution is held after being placed in an inert atmosphere as described above. As the holding atmosphere, the holding temperature is preferably in the range of 10 ° C. to 45 ° C.
It is more preferably in the range of 5 ° C to 30 ° C, particularly preferably in the range of 18 ° C to 23 ° C. If the temperature is lower than this temperature, gelling of the coating solution proceeds, making it difficult to obtain a uniform coating solution for the charge transfer layer. If the temperature is higher than this temperature, the liquid properties after holding are not constant and the charge transfer layer is also uniform. This is because it becomes impossible to obtain a coating liquid for use. Under such temperature,
By maintaining the coating solution for a certain period of time, the liquid properties of the coating solution for the charge transfer layer are stabilized, and a coating solution exhibiting good electrophotographic properties can be obtained. The holding time is preferably in a range of 20 hours to 2 weeks, more preferably in a range of 30 hours to 1 week, further preferably in a range of 40 hours to 72 hours, and particularly preferably in a range of 45 hours to 50 hours. preferable. If the holding time is short, the coating solution for the charge transfer layer will not be stable and uniform, and if the holding period is long, extra effort will be required to control the coating solution temperature and gelation due to management error. In some cases, and the deterioration of the coating liquid may occur in some cases.

Next, an electrophotographic photosensitive member according to another embodiment of the present invention will be described. Such an electrophotographic photoreceptor is obtained by uniformly applying a coating solution for a charge transfer layer obtained by the above-mentioned production method on a conductive support to form a charge transfer layer.
The thickness of the charge transfer layer is preferably 10 μm to 40 μm.
5 μm to 35 μm is more preferable, and 20 μm to 3 μm.
0 μm is particularly preferred. The undercoat layer is first formed on the conductive support using the above-described undercoat layer coating solution, and then the electric charge is formed on the undercoat layer using the above-described charge generation layer coating solution. It is preferable that the charge transfer layer is formed on the formation layer.
As a method for applying the charge transfer layer, any method such as spray coating, nozzle coating, blade coating, spin coating, and dip coating may be used. Of these, dip coating is particularly preferable.

Next, an image forming apparatus according to another embodiment of the present invention will be described. Various types of such image devices are already known as electrophotographic image forming devices, and basically include a charging device, an exposure device, a developing device, a transfer device, and a cleaning device along the outer peripheral surface of an electrophotographic photosensitive member. Image device. In the present invention, as an electrophotographic photoreceptor in such an image forming apparatus, an electrophotographic photoreceptor formed by uniformly applying a coating solution for a charge transfer layer obtained by the above-described production method onto a conductive support. Is characterized by using.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Example 1 First, a coating solution for an undercoat layer, a coating solution for a charge generation layer, and a coating solution for a charge transfer layer were prepared.

[Coating solution for undercoat layer] A mixed alcohol (methanol / n-propanol = 7/3) solution of the following copolymerized polyamide (number average molecular weight: 35,000):
The mixture was placed in a closed container at 65 ° C. and dissolved under stirring for 3 hours (step 1). Thereafter, the solution was heated at 68 ° C. to 73 ° C. for 30 minutes (step 2). The boiling point of methanol, which is a solvent having a low boiling point in the mixed solvent, is about 66 ° C. At this time, the pressure in the heated container increased with time. A mixed alcohol (methanol / n-propanol = 7/3) solution of alumina [manufactured by Showa Denko KK: UA-5305], which has been ultrasonically dispersed in advance, is mixed with the solution thus treated using a homomixer. (Step 3). The mixture was placed in a sealed container, and mixed and dispersed while heating at 68 ° C. to 73 ° C. for 1 hour (step 4). Then, after filtration, a dispersion treatment was performed with ultrasonic waves for 2 hours (step 5). Thus, UA-5305 / copolyamide = 1
An undercoat layer coating solution having a composition of 1: 1 (weight ratio) and a solid content of 8% was prepared.

Embedded image

[Coating solution for charge generation layer] 500 parts of 1,2-dimethoxyethane was added to 10 parts of Y-type oxytitanium phthalocyanine and 5 parts of polyvinyl butyral (trade name # 6000-C, manufactured by Denki Kagaku Kogyo KK). Then, the mixture was pulverized and dispersed by a sand grind mill to prepare a coating solution for the charge generation layer.

[Coating Solution for Charge Transfer Layer] 56 parts by weight of the following hydrazone compound:

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14 parts by weight of the following hydrazone compound:

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And 1.5 parts by weight of the following cyan compound

Embedded image

And 100 parts by weight of the following polycarbonate resin (monomer molar ratio 1: 1) having two repeating structural units, which is produced by the production method described in Examples of JP-A-3-221962.

Embedded image Was dissolved in a mixed solvent of 1,4 dioxane and tetrahydrofuran to prepare a coating solution for a charge transfer layer. 15 liter of the adjusted dispersion was poured into an 18-liter iron container, purged with nitrogen, and then sealed. After sealing, it was kept under an inert atmosphere at 20 ° C. for 48 hours to obtain a coating solution for a charge transfer layer.

[Conductive Support] A 6063 aluminum cylinder having an outer diameter of 60 mm, a length of 350 mm and a wall thickness of 1.0 mm having a mirror-finished surface was prepared as a conductive support. A coating film was formed on the conductive support as follows.

[Coating Step] The conductive support was immersed in the undercoat layer coating solution prepared as described above. Next, the conductive support was pulled up. The thickness of the obtained undercoat layer is 1.25.
μm. It was air-dried at room temperature to form an undercoat layer.

[Formation of Charge Generation Layer] Next, the conductive support having the undercoat layer formed thereon was immersed in the coating solution for charge generation layer prepared as described above. Next, the conductive support was pulled up. The thickness of the obtained charge generation layer was 1.5 μm. Air drying was performed at room temperature to form a charge generation layer.

[Formation of Charge Transfer Layer] Next, the conductive support having the charge generation layer formed thereon was immersed in the coating solution for charge transfer layer prepared as described above. When the coating solution for the charge transfer layer was visually confirmed, no gelled portion was found. Next, the conductive support was pulled up. The thickness of the obtained charge generation layer was 21 μm. 100 ° C humidity 1
The charge transfer layer was dried in a 0% drying chamber for 1 hour. Thus, five electrophotographic photosensitive members were manufactured.

The obtained electrophotographic photosensitive member was incorporated in an image forming apparatus. Each of the image forming apparatuses manufactured as described above was able to obtain a uniform image.

The characteristics of the electrophotographic photosensitive member were measured in an environment at a room temperature of 23 ° C. and a humidity of 45%. V0 (surface potential) refers to a charging potential measured under non-exposure conditions while rotating the electrophotographic photosensitive member under a set charging condition, and a lower value is more preferable. Vr (residual potential)
The term “electric potential” means a potential when the main power supply is turned off while the electrophotographic photoreceptor is rotated after exposure and only static elimination light is irradiated, and the lower the value, the more preferable.

[Example 2] The holding temperature was from 18 ° C to 22 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 41 hours.

[Example 3] The holding temperature was from 24 ° C to 28 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 72 hours.

[Example 4] The holding temperature was 16 ° C to 19 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 32 hours.

[Example 5] The holding temperature was from 24 ° C to 26 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 80 hours.

[Example 6] The holding temperature was 20 ° C to 22 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 55 hours.

[Example 7] The holding temperature was 13 ° C to 15 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 70 hours.

[Example 8] The holding temperature was 32 ° C to 34 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 20 hours.

Comparative Example 1 An electrophotographic photoreceptor was prepared by preparing five charge transfer layer coating solutions in the same manner as in Example 1 except that the step of holding the charge transfer layer coating solution was not performed. did. In an image forming apparatus incorporating the electrophotographic photosensitive member manufactured as described above, unevenness occurs in an image of each apparatus. Further, the electrophotographic characteristics were measured in the same manner as in Example 1.

Comparative Example 2 Five electrophotographic photosensitive members were produced in the same manner as in Example 1 except that the holding temperature was 6 ° C. to 9 ° C. and the holding time was 32 hours. Part of the coating solution for the charge transfer layer was gelled.

[Comparative Example 3] The holding temperature was 50 ° C to 52 ° C.
Then, five electrophotographic photosensitive members were manufactured in the same manner as in Example 1 except that the holding time was 32 hours.

The measurement results of the electrophotographic characteristics were as follows. Note that, in Comparative Examples 1 and 2, since there was a difference in electrophotographic characteristics between the respective electrophotographic photosensitive members, an average value of five electrophotographic photosensitive members is shown.

According to the present invention, since the coating solution for the charge transfer layer is stabilized, it is possible to obtain an electrophotographic photosensitive member having no variation in electrophotographic characteristics and an image forming apparatus.

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Claims (6)

[Claims] 1. A step of preparing a coating solution for a charge transfer layer comprising at least a charge transfer material, a binder resin and a solvent, and holding the coating solution in an inert atmosphere at a temperature of 10 ° C. to 45 ° C. for a certain time. A method for producing a coating solution for a charge transfer layer for an electrophotographic photoreceptor, comprising: 2. The method for producing a coating solution for a charge transfer layer for an electrophotographic photosensitive member according to claim 1, wherein the holding temperature is from 15 ° C. to 30 ° C. 3. The method for producing a coating solution for a charge transfer layer for an electrophotographic photosensitive member according to claim 1, wherein the holding time is from 20 hours to 2 weeks. 4. The charge transfer layer coating for an electrophotographic photoreceptor according to claim 1, wherein the atmosphere under inert atmosphere is a nitrogen atmosphere in which the adjusted coating solution for the charge transfer layer is sealed. Liquid production method. 5. A charge transfer formed by using the charge transfer layer coating solution produced by the method for producing a charge transfer layer coating solution for an electrophotographic photosensitive member according to claim 1. An electrophotographic photosensitive member comprising a layer. 6. A charge transfer formed by using the charge transfer layer coating solution produced by the method for producing a charge transfer layer coating solution for an electrophotographic photosensitive member according to claim 1. Description: An image forming apparatus using an electrophotographic photosensitive member having a layer.