JPH11133636A - Coating composition for electrophotographic photoreceptor, electrophotographic photoreceptor and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain characteristics small in toxicity, free from problems of environment, particularly ozone hole, carcinogenesis or the like, exhibiting excellent electric characteristic and image characteristic over a long period from the beginning of image forming and having excellent coating property, multi-layer property or the like by dissolving a high molecular weight polycarbonate based binder into a compound having a (substituted) dioxolane nucleus. SOLUTION: The high molecular polycarbonate based binder is dissolved in the compound having the (substituted) dioxolane nucleus. The compound having the dioxolane nucleus is 1,3-dioxolane. The viscosity average molecular weight of the high molecular weight polycarbonate based binder is larger than 100,000 and smaller than 800,000. When a carbonate having a larger viscosity average molecular weight than 100,000 is used with a dioxolane solvent, the mechanical durability is remarkably improved provably by the entanglement and the synergism of polymer chains in a coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for an electrophotographic photosensitive member, an electrophotographic photosensitive member, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, or silicone as a main component has been widely used. However, these are not always satisfactory in sensitivity, thermal stability, moisture resistance, durability, and the like. In addition, some inorganic photoreceptors contain substances that are harmful to the human body in the photoreceptor, and thus pose a problem in disposal. There is.

In order to overcome the disadvantages of these inorganic photoconductors, research and development of organic photoconductors having a photosensitive layer containing various organic photoconductive compounds as main components have been actively conducted in recent years. In particular, a function-separated type photoreceptor in which the charge generation function and the charge transport function are respectively assigned to different substances allows each material to be selected from a wide range, and a photoreceptor having any performance can be relatively easily formed. A lot of research has been done because they can be produced, and many of them are practically used.

[0004] To prepare these organic photoreceptors, a compound having a charge generation function and a charge transport function is applied in a layer form on a conductive support. Therefore, the coating composition usually has a multilayer structure, and each layer is formed by applying a coating composition obtained by dissolving a solid compound with a solvent using various coating methods.

However, organic solvents, particularly solvents having a high solubility and a suitable boiling point suitable for industrial production, are often harmful, and those having excellent properties, such as halogen-based solvents, tend to be strong.

Needless to say, as long as it is a solvent used for the production of a photoreceptor, it cannot be used unless it has solubility and an appropriate boiling point and does not adversely affect the characteristics as an electrophotographic photoreceptor. The need for a solvent that satisfies all of these was extremely high.

On the other hand, as a binder for a photosensitive layer of an electrophotographic photosensitive member used at this time, attention has been paid to polycarbonate because of its good electrical properties, but at present, it is still not possible to fully exploit its advantages.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to use a polycarbonate, a solvent containing no halogen as a coating solvent, and to reduce environmental toxicity, especially ozone hole and carcinogenicity. A coating composition for an electrophotographic photoreceptor, an electrophotographic photoreceptor having excellent properties such as excellent coating stability, excellent electric potential characteristics and image characteristics over a long period of time from the initial stage of image formation, and excellent coatability and layering properties; It is to provide a manufacturing method thereof.

[0009]

The object of the present invention is achieved by one of the following constitutions.

(1) A coating composition for an electrophotographic photosensitive member, wherein a high molecular weight polycarbonate binder is dissolved in a compound having a substituted or unsubstituted dioxolane nucleus.

(2) The coating composition for an electrophotographic photosensitive member according to (1), wherein the compound having a dioxolane nucleus is 1,3-dioxolane.

(3) The coating composition for an electrophotographic photosensitive member according to (1) or (2), wherein the high molecular weight polycarbonate binder has a viscosity average molecular weight of more than 100,000 and less than 800,000.

(4) The coating composition for an electrophotographic photosensitive member according to (1), (2) or (3), wherein the charge transporting substance is dissolved.

(5) The coating composition for an electrophotographic photosensitive member according to any one of (1) to (4), wherein a silicone oil is dissolved.

(6) The coating composition for an electrophotographic photosensitive member according to any one of (1) to (5), wherein an antioxidant is dissolved.

(7) A method for producing an electrophotographic photoreceptor, comprising applying a coating composition obtained by dissolving a high-molecular-weight polycarbonate-based binder to a compound having a substituted or unsubstituted dioxolane nucleus on a conductive support. .

(8) The coating composition is (2) to (6).
The method for producing an electrophotographic photosensitive member according to (7), which is the coating composition for an electrophotographic photosensitive member according to any one of the above.

(9) The method for producing an electrophotographic photoreceptor according to (7) or (8), wherein the coating composition is applied on a conductive support by a cyclic amount-control type coating machine.

(10) An electrophotographic photoreceptor containing a compound having a substituted or unsubstituted dioxolane nucleus and a high molecular weight polycarbonate binder.

(11) The electrophotographic photosensitive member according to (10), wherein the compound having a dioxolane nucleus is 1,3-dioxolane.

(12) The electrophotographic photosensitive member according to (10) or (11), wherein the high-molecular-weight polycarbonate binder has a viscosity average molecular weight of more than 100,000 and less than 800,000.

(13) The electrophotographic photosensitive member according to (10), (11) or (12), which contains a charge transport material.

(14) The electrophotographic photosensitive member according to any one of (10) to (13), further comprising a silicone oil.

(15) The electrophotographic photosensitive member according to any one of (10) to (14), further comprising an antioxidant.

(16) The weight of the residual solvent of the dioxolane derivative in the photoreceptor is 20 to 50,000 ppm of the total weight of the photosensitive layer.
The electrophotographic photosensitive member according to any one of (10) to (15), wherein

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, the coating solvents for electrophotographic photoreceptor layers 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, and these are environmental problems, carcinogenicity and the like. From the point of view of the use restrictions.

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 the case of a charge transporting layer, in particular, a film thickness of 12 μm or more is required. However, when polycarbonate is used as a binder, a coating solution having a high concentration of at least 5% by weight or more, preferably 8% by weight or more. And 300 cp (22
℃). However, such characteristics cannot be obtained with the above-mentioned organic solvent containing no halogen, and therefore, it may be necessary to adopt a method in which coating is performed in two or three applications.

As will be described later, polycarbonate is often used as an excellent binder in the photosensitive layer of an electrophotographic photosensitive member, but the stability of the coating solution is insufficient with the above solvent. As a good solvent containing no halogen,
There is dioxane, a cyclic ether containing two oxygen atoms in the molecule, but dioxane is highly toxic and carcinogenic and cannot be put into the manufacturing process.

As a result of diligent studies, the present inventors have found that the above-mentioned objects of the present invention can be achieved by using dioxolane and its derivatives, and have reached the present invention.

The dioxolane or dioxolane derivative of the present invention (hereinafter sometimes referred to as the compound of the present invention) is a compound having a dioxolane nucleus containing two oxygen atoms which are not adjacent to each other in a molecule and are a cyclic 5-membered ether compound. is there. Among these, the dioxolane derivative according to the present invention has a dioxolane nucleus in the molecular structure, and can be dried when the high-molecular-weight polycarbonate binder and other additives used in the present photoreceptor are dissolved to produce the photoreceptor. What is necessary is just to use what has a boiling point of 200 degreeC or less normally.

In the present invention, as the compound having a dioxolane nucleus, specifically, a compound represented by the following general formula (A) is preferably used.

[0034]

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(Wherein, R _{1 to} R ₆ are a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms,
Represents functional groups of 4 to 4. R ₅ and R ₆ or R ₁ at least the to R ₄ bonded two groups may form a ring. The substituent of this alkyl group may be any,
Preferable examples include an alkoxy group, an acyl group, an acyloxy group and a hydroxyl group each having 1 to 4 carbon atoms. The ring formed by combining R ₅ and at least two of R ₆ or R _{1 to} R ₄ includes any ring, preferably a 5- to 6-membered aromatic ring (for example, a benzene ring) or ,
Non-aromatic rings (for example, cyclohexane ring) are mentioned.

Of these, one of R ₅ and R ₆ is preferably a hydrogen atom, and both R ₁ and R ₃ are preferably hydrogen atoms, and all of R _{1 to} R ₆ are hydrogen atoms. Are particularly preferred.

The boiling point of the compound of the present invention is 2 at normal pressure.
The temperature is preferably not higher than 00 ° C, and the lower limit is preferably not lower than 70 ° C. More preferably, those having a boiling point of 150 ° C or lower and 74 to 130 ° C are particularly preferable.

The reason for this is that if the boiling point is high, the drying step becomes long, which is disadvantageous in terms of cost.
Higher values are practically disadvantageous.

Specific examples of the compounds which can be preferably used in the present invention are shown below.

[0040]

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[0041]

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[0042]

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[0043]

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Further, the content of the compound of the present invention remaining in the produced electrophotographic photoreceptor is 5% based on the total weight of the photosensitive layer.
It is desirable that the content be 0.000 ppm or less, and the lower limit be 20 ppm or more. More preferably, 30 to 1
Preferably, the content is 0.00000 ppm. When dried to less than 20 ppm, the sensitivity tends to decrease, and when it exceeds 50,000 ppm, the storage stability of the potential over time tends to deteriorate.

The residual content of the compound of the present invention varies slightly depending on the thickness of the photosensitive layer, the affinity with the binder resin, the coating speed, the diameter of the drum as the photosensitive member support, the manufacturing process, and the like. It is good to produce while confirming by analysis at the time of manufacturing. The content is controlled by a preferable combination of a drying temperature, a drying time, a drying air speed and an air volume.

The content can be detected by a method well known to those skilled in the art, for example, gas chromatography.

The photoreceptor of the present invention achieves improved durability by increasing the molecular weight of the polycarbonate constituting the surface layer. However, if the solubility in the solvent is poor, a coating solution having a high concentration cannot be prepared, or the viscosity increases so much that coating cannot be performed. A combination of a dioxolane compound and a high molecular weight polycarbonate as in the present invention is preferable because of a small increase in viscosity and good coatability.

The polycarbonate used in the present invention has a so-called —O—CO—O— bond in the molecule.
Includes polycarbonate copolymers and the like.

A typical polycarbonate preferably used in the present invention contains structural units represented by the following general formulas (1), (2), (3) and (4).

[0050]

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(Wherein, R _{1 to} R ₈ each independently represent a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group, cycloalkyl group or aryl group having 1 to 10 carbon atoms, i. Is an integer of 4 to 11.

R ₉ represents an alkyl group having 1 to 9 carbon atoms, a cycloalkyl group or an aryl group. )

[0053]

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(Wherein, R _{10 to} R ₁₇ each independently represent a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group, cycloalkyl group or aryl group having 1 to 10 carbon atoms.)

[0055]

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(In the formula, R _{20 to} R ₂₇ each independently represent a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group, cycloalkyl group or aryl group having 1 to 10 carbon atoms.)

[0057]

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(Wherein, R ₃₁ and R ₃₂ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group or an aryl group, and R _{33 to} R ₄₈ each independently represent a hydrogen atom , A halogen atom, or a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a cycloalkyl group or an aryl group, wherein k and m are each a positive integer, and k / m is 1 to 10. The polycarbonate of the present invention preferably has a repeating structural unit represented by any one of the general formulas (1) to (4), and includes not only homopolymers thereof but also copolymers thereof or with other monomers. Polymers are also included.

It has been known that the mechanical strength of the resin is effective when a high molecular weight polycarbonate is used, and that the mechanical strength increases as the molecular weight increases. However, when a polycarbonate having a viscosity average molecular weight of more than 100,000 is used together with a dioxolane solvent according to the present invention, the synergistic effect of polymerizing the binder resin and possibly increasing the entanglement of the polymer tune in the coating film dramatically increases the mechanical efficiency. It was found that the mechanical durability was improved.

The polycarbonate of the present invention preferably has a viscosity average molecular weight of more than 100,000 and less than 800,000,
More preferably, it is more than 100,000 and not more than 500,000.

The following are specific examples of the polycarbonate.

[0062]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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The photoreceptor of the present invention preferably contains a silicone oil to improve coatability.

As silicone oil, JP-A-54-1
No. 43643, No. 57-5050, No. 57-2124
No. 53, No. 59-208556, No. 63-80262
JP-A-1-234854 and 4-199154
And silicone oils described in JP-A-5-27456 are preferred.

The amount added to the photosensitive layer is preferably from 10 to 1000 ppm by weight based on the solid content of the layer. Also, dioxolane is known to generate peroxide during storage and storage, and it is preferable to add an antioxidant (AO agent).

The antioxidant is described in JP-A-7-9270.
No. 2 and Japanese Patent Application No. 8-296278 are preferred.
That is, preferred antioxidants having a hindered phenol group in the molecule are advantageous in terms of the stability of the coating solution composition and the stability of the repetition characteristics and potential of the formed photoreceptor, and The agent may use a plurality of mixtures.

The amount of the antioxidant added is from 20 to 50,000 ppm, preferably from 50 to 300 ppm, based on the coating composition.
00 ppm is good. 0.1 for the total solids of the dried coating.
001 to 10%, preferably 0.01 to 5%.

If the addition amount is small, the storage stability of the solvent and the repetition characteristics of electrophotography are poor, and if the addition amount is too large, the residual potential rises significantly and image fog occurs.

The antioxidants used in the present invention include:
There is no particular limitation on the chemical structure or the like as long as it meets the above conditions. Examples of preferably used compounds include, for example, those having a hindered amine structural unit or a hindered phenol structural unit, or those having both, an organic phosphorus compound or an organic sulfur compound, but are not limited thereto. is not.

(1) Examples of compounds having hindered phenol structural units

[0076]

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[0077]

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[0078]

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[0079]

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[0080]

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[0081]

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[0082]

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[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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(2) Examples of compounds having hindered amine structural units and hindered phenol structural units

[0089]

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[0090]

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[0091]

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(3) Examples of Organic Phosphorus Compounds The following are typical examples of compounds represented by the general formula RO-P (OR) -OR. Here, R represents a hydrogen atom, a substituted or unsubstituted alkyl group, alkenyl group or aryl group.

[0093]

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[0094]

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(4) Organic Sulfur Compounds The following are typical examples of the compounds represented by the general formula RSR. Here, R represents a hydrogen atom, a substituted or unsubstituted alkyl group, alkenyl group or aryl group.

[0096]

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The photoreceptor of the present invention is desirably a laminated photoreceptor having a charge generation layer facing down and a charge transport layer facing up.

Coating is preferably performed using a cyclic amount-regulated coating machine (CSH coating machine). For example, Japanese Patent Application Laid-Open No. 58-189061,
Japanese Patent Application No. 7-128023, 7-162021
An extrusion type coater as described in Japanese Patent Application Laid-Open No. 60-95440 or JP-A-60-95440 is preferable. As another example, a spray coater as described in JP-A-2-272567 may be used.

Hereinafter, the annular amount control type coating method will be described.

FIG. 1 is a schematic sectional view of a coating apparatus according to the present invention. In FIG. 1, cylindrical substrates 1A and 1B vertically overlapped along a center line Y, and the cylindrical substrates 1
A and 1B show a slide hopper type coating apparatus 3 for sequentially coating a coating liquid 2 for a photosensitive layer.

An application liquid slide surface 4 of the application liquid 2 is formed so as to surround the cylindrical substrate 1A, and the application liquid 2 supplied to the application liquid slide surface 4 is sequentially applied to the cylindrical substrate 1A. It is configured to do so. As a coating method, the annular coating device 3 is fixed, and the cylindrical substrate 1A is moved along the center line Y.
Is applied from the upper end while moving upward in the direction of the arrow. In order to supply the coating liquid 2 to the coating liquid slide surface 4 of the coating apparatus 3, a liquid feeding pump 6-1, a liquid feeding pipe 6-1 ′, and a coating liquid supply unit 6A are provided from an externally provided coating liquid tank 5.
To supply the coating liquid 2 to the ring-shaped coating device 3.

Next, the supplied coating liquid 2 is supplied to an annular coating liquid distribution chamber 7 formed in the annular coating apparatus 3 and sent from the coating liquid distribution slit 8 to an endless coating liquid outlet. The coating liquid 2 is continuously supplied from 9 to the coating liquid slide surface 4, and the coating liquid 2 is applied to the entire peripheral surface of the cylindrical substrate 1A. Reference numeral 12 denotes a liquid storage section for storing the coating liquid 2 dropped from the coating liquid slide surface 4.

FIG. 2 is a perspective view of the slide hopper type coating apparatus 3 shown in FIG. 1 with a part cut away.

FIG. 3 is a schematic cross-sectional view of a coating apparatus showing a simultaneous multi-layer coating method for simultaneously coating the cylindrical substrates 1A and 1B with a coating solution to be a photoreceptor using the slide hopper type coating apparatus 3. .

In FIG. 3, the cylindrical substrates 1A and 1B which are vertically overlapped along the center line Y, and the cylindrical substrates 1
Reference numerals A and 1B denote an annular coating device 3 for sequentially applying the coating liquid 2 for photosensitivity. As shown in the figure, a coating liquid slide surface 4 of the coating liquids 2 and 2A is formed so as to surround the cylindrical substrate 1A, and the coating liquids 2 and 2A supplied to the coating liquid slide surface 4 are formed.
Are sequentially applied to the cylindrical substrate 1A. As the coating method, the annular coating device 3 is fixed, and the coating is performed from the upper end while the cylindrical substrate 1A is moved upward in the direction of the arrow along the center line Y. The coating device 3
In order to supply the coating liquids 2 and 2A to the coating liquid slide surface 4 of FIG.
The coating liquid is sent from the liquid supply pipe 6-1 'and the coating liquid supply section 6A to the coating liquid distribution chamber 7.

The feeding of the liquid from the coating liquid tank 51 to the coating liquid distribution chamber 71 is performed in the same manner.

Next, the supplied coating liquids 2 and 2 A are supplied to the coating liquid distribution chamber 7 formed in the coating apparatus 3, and the coating liquid 2 is supplied to the annular coating liquid distribution chamber 7 formed in the coating apparatus 3. The coating liquid 2A is supplied to the liquid distribution chamber 71. First, the applied coating liquid 2 is continuously supplied to the coating liquid slide surface 4 from an endless coating liquid outlet 9 through a coating liquid distribution slit 8, and is first applied to the entire peripheral surface of the cylindrical substrate 1A. The application liquid 2 is applied.

Further, the coating liquid 2A is supplied to the coating liquid distribution chamber 71. The supplied coating liquid 2A is continuously supplied onto the surface of the coating liquid 2 from an endless coating liquid outlet 91 through a coating liquid distribution slit 81, and the cylindrical substrate 1
A coating liquid 2 is first applied over the entire peripheral surface of A, and a coating liquid 2A is applied thereon by multi-layer coating.

Reference numeral 12 denotes a liquid storage section for storing the coating liquid 2 dropped from the coating liquid slide surface 4.

FIG. 4 is a schematic cross-sectional view of a coating apparatus used in the sequential multi-layer coating method, in which the coating apparatuses 3 used in the embodiment of FIG. 1 are vertically arranged. This is also an endlessly formed cylindrical substrate 1A as shown in FIG.
1B is an example of an embodiment in which a coating solution is applied in a multi-layer manner on 1B.

First, in the same manner as in FIG.
Is applied to the cylindrical substrate 1A. As the coating method, the coating device 3 is fixed, and the coating is performed from the upper end while the cylindrical substrate 1A is moved upward in the direction of the arrow along the center line Y. In order to supply the coating liquid 2 to the coating liquid slide surface 4 of the coating device 3, a liquid supply pump 6-1, a liquid supply pipe 6-1 ′, and a coating liquid supply unit 6A are provided from a coating liquid tank 5 provided outside. The coating liquid is sent to the coating liquid distribution chamber 7 (the liquid is also sent from the coating liquid tank 52 to the coating liquid distribution chamber 72).

Thus, the coating liquid 2 is supplied to the annular coating liquid distribution chamber 7 formed in the coating apparatus 3, and the coating liquid 2 is continuously supplied to the coating liquid slide surface 4 through the coating liquid distribution slit 8 through an endless coating liquid outlet 9. Is applied to the entire surface of the cylindrical substrate 1A.

Further, a coating device 32 is provided above the coating device 3.

The cylindrical substrate 1A on which the first coating liquid 2 has been applied rises in the direction of the arrow and enters the coating liquid slide surface 42 of the coating device 32. Coating liquid slide surface 42
The coating liquid 2A supplied to the cylindrical base material 1A is sequentially coated on the surface of the coating liquid 2 applied to the cylindrical substrate 1A. As the coating method, the coating device 32 is fixed in the same manner as described above, and the multilayer coating is performed from the upper end while the cylindrical substrate 1A is moved upward in the direction of the arrow along the center line Y.

In order to supply the coating liquid 2A to the coating liquid slide surface 42 of the annular coating apparatus 32, a coating liquid supply section of a liquid feed pump is connected to the coating apparatus 32 from a coating liquid tank 52 provided outside (connection). The method is the same as that for the coating apparatus 3), and the coating liquid 2A is supplied. Next, the supplied coating liquid 2A is supplied to an annular coating liquid distribution chamber 72 formed in the coating device 32, and is applied to the coating liquid slide surface 42 from an endless coating liquid outlet 92 through a coating liquid distribution slit 82. The liquid 2A is continuously supplied, and the coating liquid 2A is applied to the entire peripheral surface of the coating liquid 2 applied to the cylindrical substrate 1A.

[0116]

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

Example 1 Photosensitive drum No. 1 A mirror-finished 80 mm diameter conductive support was used.
An aluminum drum support having a height of 355 mm was used.

The coating solution composition U was formed on the support as described below.
CL-1 was prepared and applied to a dry film thickness of 1.0 μm.

[0119] 1. UCL-1 coating liquid composition Ethylene-vinyl acetate copolymer (Elvacs 4260, manufactured by Du Pont-Mitsui Chemicals) 50 g Toluene / n-butanol = 5/1 (vol ratio) 2000 ml Coating liquid on this UCL layer as follows The composition CGL-1 was dispersed and prepared, and applied so as to have a thickness of 1.5 μm.

[0120] 2. CGL-1 coating solution composition Y-type titanyl phthalocyanine (CGM-1) 100 g Silicone resin (KR-5240 manufactured by Shin-Etsu Chemical Co., Ltd.) 100 g t-butyl acetate 1000 ml A dispersion of the above coating solution composition for 17 hours using a sand mill.

A coating solution composition CTL-1 was prepared on the CGL layer as described below, and the CS was adjusted to a dry film thickness of 23 μm.
H, and dried for 1 hour at 120 ° C. 1 was obtained.

The applicability was good when the film thickness variation in the image area was within ± 2 μm.

[0123] 3. CTL-1 coating liquid composition CTM-1 500 g polycarbonate (Example Compound P ₁ -5, Mv8 ten thousand) 560 g dioxolane (No.1, bp74~75 ℃) (manufactured by KF-54 manufactured by Shin-Etsu Chemical Co.) 2800 ml silicone oil total solids Example 2 Photoconductor drum No. 2 A mirror-finished diameter of 80 mm was used as the conductive support.
An aluminum drum support having a height of 355 mm was used.

The coating solution composition U was formed on the support as described below.
CL-2 was prepared and applied to a dry film thickness of 1.0 μm.

[0125] 1. UCL-2 coating liquid composition Copolymer nylon resin (CM-8000, manufactured by Toray Industries, Inc.) 2 g Methanol / n-butanol = 10/1 (vol ratio) 1000 ml The following coating composition CGL-2 is dispersed on this UCL It was prepared and applied to a dry film thickness of 1.5 μm.

[0126] 2. CGL-2 coating liquid composition Perylene pigment (CGM-2) 50 g Butyral resin (Eslec BX-L manufactured by Sekisui Chemical Co., Ltd.) 50 g Methyl ethyl ketone 2800 ml Methyl phenyl silicone oil (KF-54 manufactured by Shin-Etsu Chemical Co., Ltd.) 100 ppm What disperse | distributed the said coating liquid composition for 20 hours using the sand mill.

A coating solution composition CTL-2-a was prepared on the CGL layer as described below and applied so as to have a dry film thickness of 19 μm, and further a coating solution composition CTL as described below was formed thereon.
-2-b was prepared and applied by a CSH coater so as to have a dry film thickness of 5 μm, and then dried at 120 ° C. for 1 hour to obtain a coated photosensitive drum No. 2 was obtained.

[0128] 3. CTL-2-a coating liquid composition CTM-2 500 g polycarbonate (Example Compound P ₁ -1, Mv10 ten thousand) 560 g dioxolane (No.1, bp74~75 ℃) 2700ml methylphenyl silicone oil (KF-54 by Shin-Etsu Chemical Co., Ltd. 3.) 20 ppm added to the total solid content. CTL-2-b coating liquid composition CTM-2 400 g polycarbonate (Example Compound P ₁ -8, Mv15 ten thousand) 560 g dioxolane (No.1, bp74~75 ℃) 2700ml dioxolane derivative (No.8, bp107 ℃) 100ml AO Agent (Compound Example 1-8) 15 g AO Agent (Compound Example 3-1) 5 g Methylphenylsilicone oil (KF-54 manufactured by Shin-Etsu Chemical Co., Ltd.) 100 ppm added to the total solid content Using a sand mill Dispersed for 20 hours.

The coatability was good. The variation in film thickness in the image area was within ± 2 μm.

Example 3 Photosensitive drum No. 3 The coating drum photosensitive no. The following OCL-1 coating composition of an overcoat layer was prepared on 1 and a dry film thickness of 3
After coating with a CSH coater to make
At 1 ° C. for 1 hour. 3
I got

[0131] OCL-1 coating liquid composition polycarbonate (Example Compound P ₂ -1, Mv20 ten thousand) 150g CTM-2 100g silicone particles (Tospearl 103 manufactured by Toshiba Silicone Co., Ltd.) 60 g dioxolane (No.1, bp74~75 ℃) 900 ml Dioxolane derivative (No. 6, bp 106 to 107 ° C.) 100 ml AO agent (Compound Example 2-1) 10 g Silicone oil (TSF-431 manufactured by Toshiba Silicone Co., Ltd.) 200 ppm added to the total solid content of the above-mentioned coating liquid composition in a sand mill For 3 hours.

The coatability was good. The variation in film thickness in the image area was within ± 2 μm.

Example 4 Photosensitive drum No. 4 As the conductive support, a mirror-finished diameter of 80 mm,
An aluminum drum support having a height of 355 mm was used.

The coating solution composition U was formed on the support as described below.
CL-4 was prepared and coated so as to have a dry film thickness of 1.0 μm to obtain a coating drum.

[0135] 1. UCL-4 coating liquid composition Titanium chelate compound (TC-750 manufactured by Matsumoto Pharmaceutical) 30 g Silane coupling agent (KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.) 17 g 2-propanol 150 ml Coating liquid composition CGL on this UCL layer as follows -4 was dispersed and prepared, and applied so as to have a thickness of 0.5 μm to obtain a coating drum.

[0136] 2. CGL-4 coating liquid composition Y-type titanyl phthalocyanine (CGM-1) 10 g Silicone resin (KR-5240 manufactured by Shin-Etsu Chemical Co., Ltd.) 10 g t-vinyl acetate 1000 ml A dispersion of the above coating liquid composition for 20 hours using a sand mill.

A coating solution composition CTL-4 was prepared on the CGL layer as described below, and CS was dried to a dry film thickness of 23 μm.
H, and then dried at 120 ° C. for 1 hour. 4 was obtained.

[0138] 3. CTL-4 coating liquid composition CTM-2 500 g polycarbonate (Example Compound P ₃ -10, Mv25 ten thousand) 560 g dioxolane (No.1, bp74~75 ℃) 2600ml dioxolane derivative (No.2, bp80~83 ℃) 200ml AO Agent (Compound Example 1-21) 10 g AO Agent (Compound Example 1-46) 7 g Silicon oil (KF-54 manufactured by Shin-Etsu Chemical Co., Ltd.) 100 ppm added to the total solid content The coatability was good. The variation in film thickness in the image area is ± 2.
It was within μm.

Comparative Example 1 In Example 1, the photosensitive drum no. CTL used in 1.
M of compound examples P ₁ -5 in place of 1 Polycarbonate
A photoconductor of Comparative Example 1 (photoconductor No. 5) was produced in the same manner as in Example 1 except that v30,000 was used.

The coatability was good. The variation in film thickness in the image area was within ± 2 μm.

Comparative Example 2 In Example 1, the photosensitive drum No. CTL used in 1.
M of compound examples P ₁ -5 in place of 1 Polycarbonate
Comparative Example 2 in the same manner as in Example 1 except that v900,000 was used
(Photoconductor No. 6) was produced.

The variation in film thickness in the image area was ± 5 μm, and the surface had streaky irregularities.

Comparative Example 3 In Example 1, the photosensitive drum no. A photoreceptor of Comparative Example 3 (photoreceptor No. 7) was produced in the same manner as in Example 1 except that THF was used instead of dioxolane used in Example 1.

The variation in film thickness in the image area was ± 3 μm, and the surface had streaky irregularities.

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[0146]

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The electrophotographic photosensitive member N obtained as described above
o. Photoconductors (Photoconductor No. 5)
The following photoreceptor characteristics were evaluated using the Konica Copier U-BIX4045.

1. Electrophotographic characteristics When the above copier was modified and equipped with a surface potentiometer, and the process of charging → exposure → static elimination was repeated 200,000 times, the difference between the second and 200,000 times black paper potential, blank paper potential and residual potential The absolute values (ΔVb, ΔVw, ΔVr, respectively) were measured and evaluated. The black paper potential referred to here is the surface potential of the photoconductor when copying a black paper original having a reflection density of 1.3. Similarly, the blank potential refers to the surface potential of the photoconductor when copying a blank document having a reflection density of 0.0.

[0149] 2. Image Evaluation The image samples after 200,000 copies were taken were examined for ground fog, image streaks such as white streaks and black streaks in halftone images, image defects due to deterioration of the photoreceptor such as shading unevenness, and blade turning.

Table 1 shows the results. The amount of abrasion was measured after 200,000 copies, and the thickness of the photoreceptor was measured and compared with the initial value.

[0151]

[Table 1]

The photoreceptor of the present invention is excellent in electrophotographic characteristics, image characteristics, and abrasion resistance, and uses a solvent containing no halogen as a coating solvent. Therefore, there are environmental problems, especially ozone hole problems and carcinogenic problems. Does not occur. Further, it can be seen that a large number of coatings have good coating stability from the beginning and have excellent properties such as layering properties in the production method.

The electrophotographic photosensitive member No. 4 was mounted on a modified Konica copier U-BIX4145 modified to a digital image exposure method using a semiconductor laser light source (780 nm), and subjected to an image forming test 200,000 times to evaluate the potential fluctuation, image evaluation and wear. The amount and the like were observed.

1. Measurement of Potential Fluctuation The potential of the unexposed portion (Vh) before and after 200,000 image forming tests and the potential of the exposed portion (Vl) when the exposure light is fully lit are measured, and the absolute value (ΔVh and ΔVl) of the difference is measured. The potential fluctuation amount of the photoreceptor before and after image formation was determined.

Table 2 shows the results.

[0156]

[Table 2]

The photoreceptor of the present invention has two images from the beginning of the image forming test.
It is excellent in electrophotographic properties, image properties and abrasion resistance over 100,000 times, and uses a solvent that does not contain halogens as a coating solvent, so it does not cause environmental problems, especially ozone hole problems and carcinogenic problems. It can be seen that the composition has excellent properties such as properties and layering properties in the production method.

As a good solvent containing no halogen in polycarbonate, there is dioxane which is a cyclic ether containing two oxygen atoms in the molecule. However, dioxane is highly toxic and carcinogenic and cannot be put into the process. .

[0159]

According to the present invention, polycarbonate is used, and a solvent containing no halogen is used as a coating solvent. The coating is less toxic and has good coating stability without environmental problems, especially ozone hole problems and carcinogenic problems. In addition, the present invention provides a coating composition for an electrophotographic photoreceptor, an electrophotographic photoreceptor, and a method for producing the same, which have excellent potential characteristics and image characteristics over a long period of time from the initial stage of image formation, and have excellent coating properties and layering properties. Can be done.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a coating apparatus according to the present invention.

FIG. 2 is a perspective view of a slide hopper type coating apparatus according to the present invention.

FIG. 3 is a schematic cross-sectional view of a coating apparatus of a simultaneous multilayer coating method.

FIG. 4 is a schematic cross-sectional view of a coating apparatus of a sequential multilayer coating method.

[Explanation of symbols]

 1A, 1B Cylindrical substrate 2, 2A Coating liquid 3, 32 Coating device 4, 42 Coating liquid slide surface 5, 51, 52 Coating liquid tank 6-1 Liquid supply pump 6-1 'Liquid supply pipe 6A Coating liquid supply unit 7, 71, 72 Coating liquid distribution chamber 8, 82 Coating liquid distribution slit

Claims (16)

[Claims] 1. A coating composition for an electrophotographic photoreceptor, wherein a high molecular weight polycarbonate binder is dissolved in a compound having a substituted or unsubstituted dioxolane nucleus. 2. The compound having a dioxolane nucleus is 1,3-dioxolane.
The coating composition for an electrophotographic photosensitive member according to the above. 3. The coating composition for an electrophotographic photosensitive member according to claim 1, wherein the high molecular weight polycarbonate binder has a viscosity average molecular weight of more than 100,000 and less than 800,000. 4. The coating composition for an electrophotographic photoreceptor according to claim 1, wherein a charge transport material is dissolved. 5. The coating composition for an electrophotographic photosensitive member according to claim 1, wherein a silicone oil is dissolved. 6. The coating composition for an electrophotographic photoreceptor according to claim 1, wherein an antioxidant is dissolved. 7. A method for producing an electrophotographic photosensitive member, comprising applying a coating composition obtained by dissolving a high molecular weight polycarbonate-based binder to a compound having a substituted or unsubstituted dioxolane nucleus on a conductive support. 8. The method for producing an electrophotographic photoreceptor according to claim 7, wherein the coating composition is the coating composition for an electrophotographic photoreceptor according to any one of claims 2 to 6. 9. The method for producing an electrophotographic photoreceptor according to claim 7, wherein the coating composition is applied on a conductive support by a cyclic amount-control type coating machine. 10. An electrophotographic photoreceptor comprising a compound having a substituted or unsubstituted dioxolane nucleus and a high molecular weight polycarbonate binder. 11. The compound having a dioxolane nucleus is 1,3-dioxolane.
0. The electrophotographic photosensitive member according to item 0. 12. The electrophotographic photosensitive member according to claim 10, wherein the high molecular weight polycarbonate binder has a viscosity average molecular weight of more than 100,000 and less than 800,000. 13. The electrophotographic photoreceptor according to claim 10, wherein the electrophotographic photoreceptor contains a charge transport material. 14. The electrophotographic photoreceptor according to claim 10, further comprising a silicone oil. 15. The electrophotographic photoreceptor according to claim 10, further comprising an antioxidant. 16. The electrophotographic photoconductor according to claim 10, wherein the weight of the residual solvent of the dioxolane derivative in the photoconductor is 20 to 50,000 ppm based on the total weight of the photosensitive layer.