JP6287366B2 - Method for producing electrophotographic photoreceptor, electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member used for an electrophotographic printer, a copying machine, a multifunction machine, and the like, and a method for manufacturing the electrophotographic photosensitive member.

  In recent years, electrophotographic technology has been widely used and applied to electrostatic copying machines, facsimiles, laser beam printers, and the like because of its immediacy and high quality images. The electrophotographic photoreceptors used in these image forming apparatuses are mainly so-called organic photoreceptors in which a photosensitive layer containing a charge generator, a charge transport agent, and a binder resin is formed on a conductive support substrate. Conventionally, polycarbonate resins used as binder resins for organic photoreceptors are mainly resins produced by a solvent method such as an interface method (interface polycondensation method) or a solution method in which bisphenols and phosgene are reacted in a solution. (See Patent Document 1). On the other hand, since the adverse effects on the human body and the environment can be reduced, in addition to the solvent method, a resin produced by a melting method in which bisphenol and carbonic acid diester are polycondensed by transesterification is widely used as an inexpensive production method. (See Patent Documents 2 and 3). In addition to bisphenol-A-polycarbonate, which is widely used as an engineering plastic as described in the above-mentioned patent document, ozone resistance is improved by using bisphenol-C-polycarbonate produced by a melting method for an electrophotographic photoreceptor. An example of this has been reported recently (see Patent Document 4). The bisphenol-A-polycarbonate resin produced by the continuous process using the melting method is superior in terms of the environment, such as not using an organic solvent with a large environmental load such as a halogen-based solvent, and not using phosgene in the polymerization process or oligomer process. Also, the electrical characteristics when used in the photoreceptor are excellent. However, the bisphenol-A-polycarbonate is poor in solubility in a solvent, and is particularly difficult to dissolve in a non-halogen solvent such as tetrahydrofuran or toluene generally used in a coating solution for an electrophotographic photoreceptor. In addition, halogen solvents such as chlorobenzene, which dissolve bisphenol-A-polycarbonate and can be used as a coating solution for a photosensitive layer for an electrophotographic photosensitive member, as compared with tetrahydrofuran and toluene, are concerned about adverse effects on the human body and the environment. .

JP 09-015874 A JP 05-239334 A JP 2000-080161 A JP 2012-185206 A

  If the photosensitive layer of the electrophotographic photosensitive member can be formed by using a non-halogen solvent while using the bisphenol-A-polycarbonate produced by the continuous production method by the melting method, the burden on the human body and the environment is small, which is advantageous in terms of cost. An electrophotographic photosensitive member can be provided, but when the bisphenol-A-polycarbonate is used alone, it is difficult to prepare a coating solution for forming a photosensitive layer, and long-term storage is impossible. Therefore, a means for preparing a coating solution for forming a photosensitive layer by mixing the bisphenol-A-polycarbonate with another resin has been considered. However, when the resins are simply mixed, the bisphenol-A-polycarbonate is The electrophotographic photosensitive member could not be produced because it was not dissolved in a non-halogen solvent.

As a result of intensive studies to solve the above problems, the present inventor has produced a polycarbonate resin (A) and a polycarbonate resin (B) having a specific structural unit, which are produced by a transesterification reaction between a carbonic acid diester and an aromatic dihydroxy compound. A step of preparing a resin composition by melt kneading, a step of preparing a coating solution for forming a photosensitive layer containing the resin composition using a non-halogen solvent, and a photosensitive layer using the coating solution for forming a photosensitive layer The manufacturing method of the electrophotographic photoreceptor which has the process of forming this was discovered. That is, the gist of the present invention resides in the following <1> to < 3 >.
<1> In the method for producing an electrophotographic photosensitive member for producing an electrophotographic photosensitive member having a photosensitive layer, the production method comprises:
Produced by a transesterification reaction between a carbonic acid diester and an aromatic dihydroxy compound.
Polycarbonate resin (A) having a structural unit represented by the following formula (1) and the following formula (2)
A step of preparing a resin composition by melt-kneading a polycarbonate resin (B) having a structural unit represented by:
Using a non-halogen solvent to prepare a coating solution for forming a photosensitive layer containing the resin composition;
Forming a photosensitive layer using the coating solution for forming a photosensitive layer;
A process for producing an electrophotographic photosensitive member, comprising:

<2> content of the polycarbonate resin (A) in the resin composition, characterized in that 5% to 25% relative to the total weight of the polycarbonate resin (A)及Beauty port polycarbonate resin (B) <1> The method for producing an electrophotographic photosensitive member according to <1>.
<3> The polycarbonate resin (A) is obtained by polycondensation of an aromatic dihydroxy compound represented by the following formula (3) and a carbonic acid diester represented by the following general formula (4) in the presence of a catalyst. The polycarbonate resin (B) is represented by the following formula (
5) an aromatic dihydroxy compound represented by, and a carbonic acid diester represented by the following general formula (4), wherein the presence of a catalyst, a polycarbonate resin obtained by polycondensation, <1> Or the manufacturing method of the electrophotographic photoreceptor as described in <2> .

(In the formula (4), ^{A 1} and ^{A 2} each independently optionally carbon atoms 1 may have a substituent
18 aliphatic groups or an aromatic group which may have a substituent is represented. )

  According to the present invention, a composition obtained by melt-kneading a bisphenol-A-polycarbonate resin and a bisphenol-C-polycarbonate resin produced by a melting method that is inexpensive and mass-produced and is environmentally superior has been conventionally used. It is possible to provide a method for producing an electrophotographic photosensitive member that can dissolve a bisphenol-A-polycarbonate resin insoluble in a halogen solvent in a non-halogen solvent, is excellent in terms of environment, and can uniformly form a photosensitive layer. .

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention.

Hereinafter, modes for carrying out the present invention (hereinafter, embodiments of the present invention) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention. The drawings used are for explaining the present embodiment and do not represent the actual size.
<Process for preparing resin composition>
The method for producing an electrophotographic photosensitive member of the present invention comprises a polycarbonate resin (A) having a structural unit represented by the following formula (1), which is produced by a transesterification reaction between a carbonic acid diester and an aromatic dihydroxy compound, and the following formula ( 2) A step of preparing a resin composition by melt-kneading the polycarbonate resin (B) having the structural unit represented by 2).

[Polycarbonate resin]
The polycarbonate resins (A) and (B) according to the present invention are produced by continuously performing a melt polycondensation reaction in the presence of a transesterification catalyst using an aromatic dihydroxy compound and a carbonic acid diester as raw materials. Is preferable (hereinafter sometimes referred to as a melting method). When the melt-process polycarbonate resin according to the present invention is used as a binder resin for the photosensitive layer of an electrophotographic photoreceptor, electrical characteristics and ozone resistance are improved as compared with the case where an interfacial polycarbonate resin is used. Do not use nitrogen atom-containing catalysts that tend to trap charge transport and cause deterioration of electrical characteristics when used repeatedly in the melting method, and chemically unstable specific end groups generated by the solvent method in the melting method. The fact that (chloroformate group) is not formed is considered to be a factor of good electrical characteristics and ozone resistance as compared with the solvent method. The viscosity average molecular weight of the polycarbonate resins (A) and (B) is 10,000 or more, preferably 15000 or more, more preferably 20000 or more from the viewpoint of abrasion resistance of the photoreceptor, and 70000 or less, preferably from the viewpoint of kneading efficiency. Is 50000 or less, more preferably 40000 or less.

[Production method of polycarbonate resin]
The method for producing a polycarbonate resin by a melting method is to prepare a raw material mixed melt of an aromatic dihydroxy compound and a carbonic acid diester that are raw materials (original preparation process), and the raw material mixed melt in the presence of a transesterification catalyst. It is preferable to carry out the polycondensation reaction in multiple stages using a plurality of reaction vessels in a molten state (polycondensation step). The reaction system may be any of a batch system, a continuous system, or a combination of a batch system and a continuous system. As the reaction tank, a plurality of vertical stirring reaction tanks and, if necessary, at least one horizontal stirring reaction tank subsequent thereto are used. Usually, these reaction tanks are installed in series and processed continuously. After the polycondensation process, the reaction is stopped, the unreacted raw materials and reaction byproducts in the polycondensation reaction liquid are devolatilized and removed, the process of adding a thermal stabilizer, mold release agent, colorant, etc., polycarbonate resin You may add suitably the process etc. which form in a predetermined particle size.

[Aromatic dihydroxy compounds]
Specific examples of the aromatic dihydroxy compound that is a raw material of the polycarbonate resin according to the present invention include an aromatic dihydroxy compound represented by the following formula (3) and an aromatic dihydroxy compound represented by the following formula (5). It is done. Since the aromatic dihydroxy compound represented by the formula (5) has one methyl group adjacent to the hydroxyl group, the oxidation of the hydroxyl group is appropriately blocked sterically, and at the same time, for example, two methyl groups are added to the hydroxyl group. Compared to the case where the groups are adjacent to each other, the methyl group does not become a steric hindrance with respect to the polymerization reaction, and the solubility of the polymer is high, the compatibility with the charge transporting material is high, and the electrical properties and mechanical properties are low. It is advantageous from the viewpoint.

[Carbonated diester]
Examples of the carbonic acid diester that is a raw material of the polycarbonate resin according to the present invention include compounds represented by the following general formula (4).

Here, in Formula (4), in Formula (4), A ¹ and A ² each independently represent an aliphatic group having 1 to 18 carbon atoms which may have a substituent, or a substituent. An aromatic group that may be present. A ¹ and A ² may be the same or different from each other. Examples of the substituent that A ¹ and A ² may have include a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a phenyl group, a phenoxy group, a vinyl group, a cyano group, Examples include an ester group, an amide group, and a nitro group. Examples of the aliphatic group include a methyl group, an ethyl group, a propyl group, and t-butyl. Examples of the aromatic group include a phenyl group, a naphthyl group, and a tolyl group. Specific examples of the carbonic acid diester compound include, for example, substituted diphenyl carbonate such as diphenyl carbonate and ditolyl carbonate, dimethyl carbonate, diethyl carbonate, and di- Examples thereof include dialkyl carbonates such as t-butyl carbonate. Among these, diphenyl carbonate (hereinafter sometimes referred to as “DPC”) and substituted diphenyl carbonate are preferable from the viewpoint of reactivity and cost. These carbonic acid diesters can be used alone or in admixture of two or more.

In the method for producing a polycarbonate resin by the melting method according to the present invention, the amount of these carbonic acid diesters used is usually 1.01 mol to 1.30 mol of carbonic acid diester compound, preferably 1 mol of aromatic dihydroxy compound. Is used in a ratio of 1.02 mol to 1.20 mol. If the molar ratio of the carbonic acid diester is excessively small, the transesterification rate decreases, making it difficult to produce a polycarbonate resin having a desired molecular weight, or increasing the terminal hydroxyl group concentration of the resulting polycarbonate resin, resulting in thermal stability. Tend to get worse. In addition, if the molar ratio of the carbonic acid diester is excessively large, the reaction rate of the transesterification decreases, and it becomes difficult to produce a polycarbonate resin having a desired molecular weight, and the residual amount of the carbonic acid diester compound in the resin. Increases, which may cause deterioration of electrical characteristics and odor. In the production of polycarbonate resin by the melting method,
Since phosgene used in solvent methods such as the interfacial method and solution method is not used in the polymerization process, there is no chloroformate residue at the terminal, whereas in the production of polycarbonate resin by the solvent method, residual chloroformate is not present at the terminal. The difference is that the group and its modifying group remain.

[Transesterification]
In the method for producing a polycarbonate resin by the melting method according to the present invention, the transesterification reaction between the carbonic acid diester and the aromatic dihydroxy compound is preferably performed in the presence of a catalyst from the viewpoint of reaction efficiency. Examples of the transesterification catalyst include, but are not particularly limited to, catalysts used when producing a polycarbonate resin by a transesterification method. Examples thereof include basic compounds such as alkali metal compounds, alkaline earth metal compounds, beryllium compounds, magnesium compounds, basic boron compounds, basic phosphorus compounds, basic ammonium compounds, and amine compounds. Among these, alkali metal compounds and alkaline earth metal compounds are preferable for practical use. These transesterification catalysts may be used alone or in combination of two or more.

The amount of transesterification catalyst used is usually in the range of 1 × 10 ⁻⁹ mol to 1 × 10 ⁻³ mol with respect to 1 mol of the wholly aromatic dihydroxy compound, but a polycarbonate resin excellent in molding characteristics and hue is used. In order to obtain, the amount of the transesterification catalyst is preferably 1.0 × 10 ⁻⁸ mol to 1 mol per 1 mol of the wholly aromatic dihydroxy compound when an alkali metal compound and / or an alkaline earth metal compound is used. It is in the range of × 10 ⁻⁴ mol, more preferably in the range of 1.0 × 10 ⁻⁸ mol to 1 × 10 ⁻⁵ mol, and particularly preferably in the range of 1.0 × 10 ⁻⁷ mol to 5.0 × 10. Within the range of ^-6 moles. If the amount is less than the above lower limit amount, the polymerization activity necessary for producing a polycarbonate resin having a desired molecular weight cannot be obtained. If the amount is more than the above upper limit amount, the polymer hue deteriorates, the amount of branching components is too large, and the fluidity. The polycarbonate resin having excellent target melting characteristics cannot be produced.

Examples of the alkali metal compound include inorganic alkali metal compounds such as alkali metal hydroxides, carbonates and hydrogencarbonate compounds; organic alkali metal compounds such as salts with alkali metal alcohols, phenols and organic carboxylic acids. It is done. Here, as an alkali metal, lithium, sodium, potassium, rubidium, cesium etc. are mentioned, for example.
Among these alkali metal compounds, a cesium compound is preferable, and cesium carbonate, cesium hydrogen carbonate, and cesium hydroxide are particularly preferable from the viewpoint of ease of removal as a residual catalyst that enables an appropriate degree of polymerization for use as a photoreceptor. .

Examples of the alkaline earth metal compound include inorganic alkaline earth metal compounds such as alkaline earth metal hydroxides and carbonates; alkaline earth metal alcohols, phenols, salts with organic carboxylic acids, and the like. It is done. Here, examples of the alkaline earth metal include calcium, strontium, barium and the like.
Examples of the beryllium compound and magnesium compound include inorganic metal compounds such as metal hydroxides and carbonates; salts of the metals with alcohols, phenols, and organic carboxylic acids.

Examples of basic boron compounds include sodium salts, potassium salts, lithium salts, calcium salts, magnesium salts, barium salts, strontium salts, and the like of boron compounds. Here, as the boron compound, for example, tetramethylboron, tetraethylboron, tetrapropylboron, tetrabutylboron, trimethylethylboron, trimethylbenzylboron, trimethylphenylboron, triethylmethylboron, triethylbenzylboron, triethylphenylboron, tributyl Examples include benzylboron, tributylphenylboron, tetraphenylboron, benzyltriphenylboron, methyltriphenylboron, and butyltriphenylboron.

Examples of the basic phosphorus compound include trivalent phosphine compounds such as triethylphosphine, tri-n-propylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, and tributylphosphine, or derivatives thereof. And quaternary phosphonium salts.
Examples of the basic ammonium compound include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, trimethylethylammonium hydroxide, trimethylbenzylammonium hydroxide, trimethylphenylammonium hydroxide, Triethylmethylammonium hydroxide, triethylbenzylammonium hydroxide, triethylphenylammonium hydroxide, tributylbenzylammonium hydroxide, tributylphenylammonium hydroxide, tetraphenylammonium hydroxide, benzyltriphenylammonium hydroxide, methyltriphenylammonium hydroxide Sid, butyl triphenyl ammonium hydroxide, and the like.

  Examples of the amine compound include 4-aminopyridine, 2-aminopyridine, N, N-dimethyl-4-aminopyridine, 4-diethylaminopyridine, 2-hydroxypyridine, 2-methoxypyridine, 4-methoxypyridine, 2 -Dimethylaminoimidazole, 2-methoxyimidazole, imidazole, 2-mercaptoimidazole, 2-methylimidazole, aminoquinoline and the like.

In the method for producing a polycarbonate resin by the melting method according to the present invention, a catalyst deactivator for neutralizing and deactivating the transesterification catalyst may be added after completion of the transesterification reaction between the carbonic acid diester and the aromatic dihydroxy compound. . The heat resistance and hydrolysis resistance of the polycarbonate resin obtained by such treatment are improved.
As such a catalyst deactivator, an acidic compound having a pKa of 3 or less, such as sulfonic acid and sulfonic acid ester, is preferable. Specifically, benzenesulfonic acid, p-toluenesulfonic acid, methyl benzenesulfonate, benzenesulfone Examples include ethyl acetate, propyl benzenesulfonate, butyl benzenesulfonate, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, propyl p-toluenesulfonate, and butyl p-toluenesulfonate. Among these, p-toluenesulfonic acid and butyl p-toluenesulfonate are preferably used.

[Melting and kneading]
A method for melt-kneading the polycarbonate resin (A) and the polycarbonate resin (B) will be described. The resin composition is obtained by melt-kneading the pellets or flakes of the polycarbonate resin (A) and the pellets or flakes of the polycarbonate resin (B) using, for example, a kneader, a twin screw extruder, a single screw extruder or the like. Can be obtained. The pellets or flakes of the polycarbonate resin (A) and the pellets or flakes of the polycarbonate resin (B) may be mixed in advance in a solid state and then kneaded, or one of them may be first melted by the mixing device. The other polycarbonate resin may be added and kneaded. Although it does not specifically limit to the temperature to knead | mix, From a viewpoint of mixing uniformity and pencil hardness, 240 degreeC or more is preferable, 260 degreeC or more is more preferable, and 280 degreeC or more is further more preferable. Moreover, 350 degrees C or less is preferable from a viewpoint of a color tone, and 320 degrees C or less is especially preferable.

The content ratio of the polycarbonate resin (A) in the resin composition is a viewpoint of cost relative to the total content of the polycarbonate resin (A) and the polycarbonate resin (B) having a structural unit represented by the following formula (2). Therefore, the lower limit is preferably 1% or more and more preferably 5% or more by mass ratio. In addition, from the viewpoint of solubility, the upper limit is preferably 30% or less, more preferably 25% or less in terms of mass ratio.

<Electrophotographic photoreceptor>
Next, constituent elements of the photoreceptor will be described. The photoreceptor is provided with an anodized layer, a conductive layer, and an undercoat layer on a conductive support, if necessary, on which a single layer type or a laminated type photosensitive layer is provided, and further a protective layer if necessary. Is built. For the conductive support, the anodized layer, and the undercoat layer, known examples disclosed in, for example, JP-A-2007-293319 can be used.

[Photosensitive layer]
As the type of the photosensitive layer, a charge generation material and a charge transport material are present in the same layer and are dispersed in a binder resin, a charge generation layer in which a charge generation material is dispersed in a binder resin, and a charge. Examples include a functional separation type (laminated type) composed of two layers of a charge transport layer in which a transport material is dispersed in a binder resin. The photosensitive layer of the electrophotographic photosensitive member used in the present invention is of any type. May be. In addition, as the laminated photosensitive layer, a charge-generating layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a charge transport layer and a charge generation layer are formed from the conductive support side. There are reverse laminated photosensitive layers provided in order, and any of them can be adopted, but a forward laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.

  A resin composition comprising a polycarbonate resin having a structure represented by the above formula (1) and a polycarbonate resin having a structure represented by the above formula (2) obtained by the melting method described above is bonded to a binder in the photosensitive layer. Used as a resin. The binder resin may be used in any layer, but is preferably in the charge transport layer of the multilayer photosensitive layer or in the single-layer photosensitive layer, and in the charge transport layer of the multilayer photosensitive layer. More preferably it is used. The resin composition may be used alone or in combination with other resins. Examples of binder resins that may be mixed include polymers and copolymers of vinyl compounds such as butadiene resins, styrene resins, vinyl acetate resins, acrylic ester resins, methacrylic ester resins, vinyl alcohol resins, and ethyl vinyl ethers, Polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicon resin, silicon-alkyd resin, poly-N-vinylcarbazole resin, etc. Can be mentioned. Of these, polyester resins and polyarylate resins are preferred from the viewpoint of printing durability.

  The charge transport layer may be a plurality of layers, and in that case, any layer may contain the resin composition. As for the content ratio of the binder resin and the charge transport material, the charge transport material is usually used at a ratio of 20 parts by mass or more with respect to 100 parts by mass of the binder resin. Especially, 30 mass parts or more is preferable from a viewpoint of residual potential reduction. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by mass or less. Among these, 110 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by mass or less is more preferable from the viewpoint of wear resistance, and 70 parts by mass or less is still more preferable from the viewpoint of scratch resistance.

[Laminated photosensitive layer]
(Charge generation layer)
As the charge generation layer, a known example disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-293319 can be used.
(Charge transport layer)
The charge transport layer contains a charge transport material, a binder resin, and other components used as necessary. Specifically, such a charge transporting layer is prepared by dissolving or dispersing a charge transporting material, the polycarbonate resin of the present application as a binder resin, and an additive in a solvent to prepare a coating solution, which is then subjected to a sequential lamination type photosensitive. In the case of a layer, it can be obtained by coating and drying on a charge generation layer, and in the case of a reverse lamination type photosensitive layer, on a conductive support (or on an undercoat layer if an undercoat layer is provided). it can.

  As the charge transport material, a known carbazole derivative, hydrazone compound, aromatic amine derivative, enamine derivative, butadiene derivative, and a material in which a plurality of these derivatives are bonded are preferable. More specifically, it is described in JP-A-2-230255, JP-A-63-225660, JP-A-58-198043, JP-B-58-32372, and JP-B-7-21646. Compounds are preferably used. Any one of these charge transport materials may be used alone, or a plurality of types may be used in any combination.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less, from the viewpoint of long life, image stability, and high resolution. The range is preferably 30 μm or less.
For the purpose of improving film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc., in both the photosensitive layer and each layer constituting it, both in the multilayer type photosensitive member and the single layer type photosensitive member. Additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be included.

[Other functional layers]
Further, in both the laminated type photoreceptor and the single layer type photoreceptor, the photosensitive layer formed by the above procedure may be the uppermost layer, that is, the surface layer, but another layer may be provided on the photosensitive layer and used as the surface layer. Good. For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like. As the protective layer, known ones such as a curable protective layer such as a photo-curing type, a thermosetting type, and an electron beam curable type, and a protective layer in which an inorganic filler is dispersed can be used.

<Step of preparing a coating solution for forming a photosensitive layer>
The photosensitive layer is prepared by dissolving or dispersing a substance to be contained in a non-halogen solvent to prepare a photosensitive forming coating solution. As the solvent or dispersion medium used for preparing the coating liquid, it is preferable to use only a non-halogen solvent, and additives and the like may be contained. The non-halogen solvent refers to a solvent having no halogen atom in the molecular structure. Specific examples of the non-halogen solvent include ethers such as tetrahydrofuran, 1,4-dioxane, dioxolane and dimethoxyethane, esters such as methyl formate and ethyl acetate, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone and 4-methoxy- Ketones such as 4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene and xylene, nitrogen-containing compounds such as n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine and triethylenediamine, acetonitrile And aprotic polar solvents such as N-methylpyrrolidone, N, N-dimethylformamide, and dimethyl sulfoxide. Moreover, these may be used individually by 1 type and may use 2 or more types together. Moreover, you may use 2 or more types together by arbitrary combinations and kinds. Among these, from the viewpoint of compatibility, the combined use of ethers and aromatic hydrocarbons is preferable, and the combined use of tetrahydrofuran and toluene is particularly preferable.

  It is preferable to adjust the coating solution for forming a photosensitive layer so that the mass ratio of the polycarbonate resin to the solvent [polycarbonate resin / solvent] is 8/100 to 30/100. From the viewpoint of solubility with the charge transport material, 25/100 or less is more preferable, and 20/100 or less is more preferable. From the viewpoint of applicability, 10/100 or more is more preferable, and 12/100 or more is more preferable.

  For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 500 mPa · s or lower, preferably 400 mPa · s or lower, at the temperature during use.

<Process for forming photosensitive layer>
The coating solution for forming the photosensitive layer is formed by repeating coating and drying processes sequentially for each layer by a known method such as dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating on a conductive support. It is formed. As coating methods for the photosensitive layer forming coating solution, dip coating method, spray coating method, spinner coating method, bead coating method, wire bar coating method, blade coating method, roller coating method, air knife coating method, curtain coating method, etc. In view of efficiency and productivity, the dip coating method is preferable.
The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

[Method for forming each layer]
Each layer constituting the above-described photoreceptor is formed by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as coating. There are no particular restrictions on the solvent or dispersion medium used for the preparation of the coating solution, but specific examples include ethers such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, dimethoxymethane, dimethoxyethane, anisole, and formic acid. Esters such as methyl and ethyl acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone and 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1, Chlorinated hydrocarbons such as 2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanol Ami , Ethylenediamine, nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds. Moreover, a non-halogen solvent is preferable from the viewpoint of reducing environmental burden.

[Method for producing coating liquid]
A coating solution can be obtained by dissolving or dispersing a substance to be contained in a layer to be formed in a solvent. For example, in the case of a charge transport layer of a laminated photosensitive layer, it can be produced by the following method. That is, charge transport material, binder resin, binder resin used in combination as necessary, additives, etc. are stirred and dissolved in an organic solvent at room temperature or while heating, and filtered with an optional filter as necessary. Adjust the liquid. At this time, when insoluble fine particles are added for the purpose of improving the lubricity and releasability of the photosensitive layer, the dispersion may be prepared by an appropriate dispersing means.

[Image forming apparatus, cartridge]
As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further includes a transfer device 5, a cleaning device 6, and a fixing device as necessary. 7 is provided. The electrophotographic photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member of the present invention. In FIG. 1, as an example, the above-described photosensitive layer forming coating solution is applied onto a cylindrical conductive support. 2 shows a drum-shaped electrophotographic photosensitive member formed. It is also possible to adopt a liquid developing system used for a photoreceptor in which the above-described photosensitive layer is formed on the surface of a sheet-like support and is made into an endless belt by ultrasonic fusion. It can be used for either negative charging or positive charging. A plurality of components such as the drum-shaped photosensitive member 1, the charging unit 2, the developing unit 4, and the cleaning unit 6 are integrally combined as a drum cartridge, and the drum cartridge is configured as a copying machine or a laser beam printer. It may be configured to be detachable from the electrophotographic apparatus main body.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded. In the following description, “part” represents “part by mass”.

<Manufacture of polycarbonate resin>
[Production Example 1] Synthesis of bisphenol-A-polycarbonate (melting method)
2,2-bis (4-hydroxyphenyl) propane (hereinafter sometimes abbreviated as “BPA”) (Honshu Chemical Co., Ltd.) 37.60 kg (about 147 mol) and diphenyl carbonate (DPC) 32.20 kg (about 150 mol), an aqueous solution of cesium carbonate was added so that the amount of cesium carbonate was 2 μmol per 1 mol of BPC to prepare a mixture. Next, the mixture was charged into a first reactor having an internal volume of 200 L equipped with a stirrer, a heating medium jacket, a vacuum pump, and a reflux condenser. Next, the operation of depressurizing the inside of the first reactor to 1.33 kPa (10 Torr) and then restoring the pressure to the atmospheric pressure with nitrogen was repeated 5 times, and the inside of the first reactor was replaced with nitrogen. After nitrogen substitution, the internal temperature of the first reactor was gradually raised through a heat medium having a temperature of 230 ° C. through the heat medium jacket to dissolve the mixture. Then, the stirrer was rotated at 300 rpm, the temperature in the heating medium jacket was controlled, and the internal temperature of the first reactor was kept at 220 ° C. The pressure in the first reactor was 101.3 kPa (760 Torr) in absolute pressure over 40 minutes while distilling off phenol produced as a by-product by the oligomerization reaction of BPC and DPC performed in the first reactor. To 13.3 kPa (100 Torr). Next, the first
The pressure in the reactor was maintained at 13.3 kPa, and a transesterification reaction was performed for 80 minutes while further distilling off phenol.

  Thereafter, the inside of the system was restored to the absolute pressure of 101.3 kPa with nitrogen, the gauge pressure was increased to 0.2 MPa, and the oligomer in the first reactor was passed through a transfer pipe heated to 200 ° C. or higher in advance. Was pumped to the second reactor. The second reactor had an internal volume of 200 L, was equipped with a stirrer, a heat medium jacket, a vacuum pump and a reflux condenser, and the internal pressure was controlled to atmospheric pressure and the internal temperature was controlled to 240 ° C. Next, the oligomer fed into the second reactor was stirred at 38 rpm, the internal temperature was raised with a heating medium jacket, and the inside of the second reactor was absolute pressure from 101.3 kPa to 13.3 kPa over 40 minutes. The pressure was reduced to. Thereafter, the temperature increase was continued, and the internal pressure was reduced from 13.3 kPa to 399 Pa (3 Torr) as an absolute pressure over an additional 40 minutes, and phenol distilled out was removed out of the system. Further, the temperature was continuously raised, and after the absolute pressure in the second reactor reached 70 Pa (about 0.5 Torr), the pressure was maintained at 70 Pa, and a polycondensation reaction was performed. The final internal temperature in the second reactor was 285 ° C. The polycondensation reaction was completed when the stirrer of the second reactor reached a predetermined stirring power.

  Next, the inside of the second reactor is restored to 101.3 kPa in absolute pressure with nitrogen, and the gauge pressure is increased to 0.2 MPa, and the polycarbonate resin is extracted in a strand form from the bottom of the second reactor, The mixture was pelletized by using a rotary cutter while being cooled at the same time. The resulting polycarbonate resin had a viscosity average molecular weight of 25,000.

[Production Example 2] Synthesis of bisphenol-C-polycarbonate (melting method)
In Production Example 1, Production Example 1 was used except that 2,2-bis (4-hydroxy-3-methylphenyl) propane (hereinafter sometimes abbreviated as “BPC”) was used instead of BPA. Similarly, a polycarbonate resin (B) was produced. The viscosity average molecular weight was 26,000.

[Production Example 3] Resin composition of polycarbonate resin (A) and polycarbonate resin (B) 15 parts of bisphenol-A-polycarbonate resin (A) obtained as in Production Example 1 and bisphenol-B-polycarbonate resin ( B) was blended in 85 parts, and kneaded at a barrel temperature of 290 ° C. by a twin-screw extruder (“TEX30XCT” manufactured by Nippon Steel Works) to obtain a polycarbonate resin composition pellet (C).

[Production Example 4] Synthesis of bisphenol-C-polycarbonate (solvent method)
BPC (Honshu Chemical Co., Ltd.) 13.80 kg / hr, sodium hydroxide (NaOH) 5.8 kg / hr and water 93.5 kg / hr were dissolved at 35 ° C. in the presence of hydrosulfite 0.017 kg / hr After that, an aqueous phase cooled to 25 ° C. and an organic phase of 61.9 kg / hour of methylene chloride cooled to 5 ° C. are supplied to a fluororesin pipe having an inner diameter of 6 mm and an outer diameter of 8 mm, respectively. In a fluororesin pipe reactor having a length of 6 mm and a length of 34 m, the reactor was brought into contact with 7.2 kg / hour of liquefied phosgene cooled to 0 ° C. separately introduced here.

The raw material is subjected to phosgenation and oligomerization reaction while flowing through phosgene and a pipe reactor at a linear velocity of 1.7 m / second for 20 seconds. At this time, the reaction temperature reached a tower top temperature of 60 ° C. in the heat insulation system. The temperature of the reaction product was adjusted by external cooling to 35 ° C. before entering the next oligomerization tank. In the oligomerization, triethylamine 5 g / hour (0.9 × 10 ⁻³ mol relative to 1 mol of BPC) was used as a catalyst, and pt-butylphenol 0.153 kg / hour was used as a molecular weight regulator. Introduced.

In this way, the oligomerized emulsion obtained from the pipe reactor is further guided to a reaction vessel equipped with a stirrer having an internal volume of 50 liters and stirred at 30 ° C. in a nitrogen gas (N 2) atmosphere to be oligomerized. Then, unreacted sodium salt of BPC (BPC-Na) present in the aqueous phase was consumed, and then the aqueous phase and the oil phase were allowed to stand and separate to obtain an oligomeric methylene chloride solution.

Of the above methylene chloride solution of oligomer, 23 kg was charged into a reaction vessel equipped with an internal volume of 70 L, Faudler blade, and 10 kg of methylene chloride for dilution was added thereto, and further 25 kg of 25% by weight sodium hydroxide aqueous solution, 6 kg of water and 2.2 g of triethylamine (1.1 × 10 ⁻³ mol relative to 1 mol of BPC) was added, and the mixture was stirred at 30 ° C. in a nitrogen gas atmosphere, and a polycondensation reaction was performed for 60 minutes to obtain a polycarbonate resin.

Next, 30 kg of methylene chloride and 7 kg of water were added, and after stirring for 20 minutes, stirring was stopped and the aqueous phase and the organic phase were separated. To the separated organic phase, 20 kg of 0.1N hydrochloric acid was added and stirred for 15 minutes to extract triethylamine and a small amount of remaining alkali component, and then stirring was stopped to separate the aqueous phase and the organic phase.
Further, 20 kg of pure water was added to the separated organic phase, and the mixture was stirred for 15 minutes, and then the stirring was stopped to separate the aqueous phase and the organic phase. This operation was repeated (three times) until no chlorine ions were detected in the extracted waste water. The obtained purified organic phase was pulverized by feeding into 40 ° C. warm water and dried to obtain a flaky powder of polycarbonate resin. The viscosity average molecular weight was 30,000.

<Manufacture and evaluation of photoconductor>
[Example 1]
A coating solution for a photoreceptor was produced as follows.
[Manufacture of coating solution for forming undercoat layer]
The undercoat layer forming coating solution was prepared as follows. Rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were used in a Henschel mixer The surface-treated titanium oxide obtained by mixing was dispersed by a ball mill in a mixed solvent having a methanol / 1-propanol weight ratio of 7/3 to obtain a surface-treated titanium oxide dispersed slurry. Composition of the dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam / bis (4-amino-3-methylcyclohexyl) methane / hexamethylenediamine / decamethylenedicarboxylic acid / octadecamethylenedicarboxylic acid The copolyamide pellets with a molar ratio of 60% / 15% / 5% / 15% / 5% are stirred and mixed with heating to dissolve the polyamide pellets, and then subjected to ultrasonic dispersion treatment. To form a subbing layer with a solid content concentration of 18.0%, containing a methanol / 1-propanol / toluene weight ratio of 7/1/2 and a surface-treated titanium oxide / copolymerized polyamide at a weight ratio of 3/1. A coating solution was prepared.

[Manufacture of coating solution for forming charge generation layer]
The charge generation layer forming coating solution was prepared as follows. As a charge generation material, 20 parts of Y-type (also known as D-type) oxytitanium phthalocyanine and 1,2- 1, which show a strong diffraction peak at 27.3 ° in the Bragg angle (2θ ± 0.2) in X-ray diffraction by CuKα rays. 280 parts of dimethoxyethane were mixed and pulverized with a sand grind mill for 1 hour for atomization dispersion treatment. Subsequently, 10 parts of polyvinyl butyral (trade name “Denka Butyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl. A binder liquid obtained by dissolving in 85 parts of 2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution L for forming a charge generation layer.

[Manufacture of Coating Solution A for Charge Transport Layer Formation]
The charge transport layer forming coating solution was prepared as follows. 35 parts of the following charge transport material CT, 100 parts of the above-mentioned polycarbonate resin composition (C) pellets, 8 parts by weight of IRGANOX 1076 manufactured by Ciba Specialty Chemicals Co., Ltd. as an antioxidant, and 0. 1 of silicone oil as a leveling agent. 05 parts was mixed with 572 parts of a mixed solvent (THF 70 wt%, TL 30 wt%) of tetrahydrofuran (hereinafter abbreviated as THF as appropriate) and toluene (hereinafter abbreviated as TL as appropriate) to prepare a coating solution for forming a charge transport layer.

[Manufacture of photoconductor]
On the 3003 series aluminum alloy tube having a diameter of 30 mm, a length of 246 mm, and a wall thickness of 0.75 mm, the coating film for forming the undercoat layer obtained as described above has a film thickness after drying of about 1.5 μm. In this way, it was dip coated and dried at room temperature to provide an undercoat layer. Subsequently, the charge generation layer forming coating solution obtained as described above is dip-coated on the undercoat layer so that the film thickness after drying is about 0.3 μm, and dried at room temperature. A charge generation layer was provided. The charge transport layer forming coating solution A obtained as described above is dip-coated on the charge generation layer so that the film thickness after drying is about 18 μm, dried at 125 ° for 20 minutes, and photosensitive Body (D) was produced.

<Image test>
The photoconductor D is mounted on a photoconductor cartridge of a tandem full-color printer C3100 (DC roller charging, LED exposure, contact non-magnetic single component development) manufactured by Oki Data, and the printing rate is 5 at a temperature of 23 ° C. and a relative humidity of 50%. %, Continuous printing of 10,000 sheets was performed. As a result, the photoconductor D had a stable image density and good image quality.

[Comparative Example 1]
In the production of the coating liquid A for forming a charge transport layer, in place of the polycarbonate resin composition (C), 15 parts of bisphenol-A-polycarbonate resin (A) obtained by the melting method of Production Example 1 was obtained. -85 parts of the polycarbonate resin (B) was mixed in the same manner as in Example 1 except that it was used as it was without being melt kneaded. As a result, the bisphenol-A-polycarbonate resin (A) was not dissolved and the charge transport layer coating was applied. The liquid could not be obtained.

  From the above results, a coating solution for an electrophotographic photosensitive member can be prepared with a non-halogen solvent by forming a composition pellet by melt-kneading bisphenol-A-polycarbonate resin (A) and bisphenol-C-polycarbonate resin (B). It has been found that the electrophotographic photosensitive member that can be prepared and applied by applying the coating solution exhibits good characteristics.

[Comparative Example 2]
In the production of the coating liquid A for forming a charge transport layer, in place of the polycarbonate resin composition (C), 15 parts of the bisphenol-A-polycarbonate resin (A) obtained by the melting method of Production Example 1 were used. When 85 parts of bisphenol-C-polycarbonate resin (B) obtained by the solvent method was mixed as in Example 1 except that it was used as it was without being melt-kneaded, bisphenol-A-polycarbonate resin (A) was dissolved. Thus, a coating liquid for forming a charge transport layer could not be obtained.

[Comparative Example 3]
In the production of the coating liquid A for forming a charge transport layer, in place of the polycarbonate resin composition (C), 15 parts of bisphenol-C-polycarbonate resin (B) obtained by the melting method of Production Example 2 is commercially available by a solvent method. 85 parts of bisphenol-A-polycarbonate resin (A) (E-2000 (viscosity average molecular weight 22,000) manufactured by Mitsubishi Engineer Plastics) was mixed in the same manner as in Example 1 except that it was used as it was without being melt kneaded. However, the bisphenol-A-polycarbonate resin (A) was not dissolved, and a coating liquid for forming a charge transport layer could not be obtained.

[Comparative Example 4]
Except for using 100 parts of the bisphenol-A-polycarbonate resin (A) obtained by the melting method of Production Example 1 instead of the polycarbonate resin composition (C) in the production of the coating liquid A for forming a charge transport layer. When mixed in the same manner as in Example 1, the bisphenol-A-polycarbonate resin (A) was not dissolved, and a charge transport layer forming coating solution could not be obtained.

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
5 Transfer device 6 Cleaning device (cleaning part)
7 Fixing Device 41 Developing Tank 42 Agitator 43 Supply Roller 44 Developing Roller 45 Regulating Member 71 Upper Fixing Member (Pressure Roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (3)

In the method for producing an electrophotographic photoreceptor for producing an electrophotographic photoreceptor having a photosensitive layer, the production method comprises:
Produced by a transesterification reaction between a carbonic acid diester and an aromatic dihydroxy compound.
Polycarbonate resin (A) having a structural unit represented by the following formula (1) and the following formula (2)
A step of preparing a resin composition by melt-kneading a polycarbonate resin (B) having a structural unit represented by:
Using a non-halogen solvent to prepare a coating solution for forming a photosensitive layer containing the resin composition;
Forming a photosensitive layer using the coating solution for forming a photosensitive layer;
A process for producing an electrophotographic photosensitive member, comprising:

Content of the polycarbonate resin (A) in the resin composition is 5% to 25% by weight ratio to the total amount of the polycarbonate resin (A)及Beauty port polycarbonate resin (B)
The method for producing an electrophotographic photosensitive member according to claim 1, wherein: The polycarbonate resin (A) is obtained by polycondensation of an aromatic dihydroxy compound represented by the following formula (3) and a carbonic acid diester represented by the following general formula (4) in the presence of a catalyst. And the polycarbonate resin (B) is represented by the following formula (5):
A polycarbonate resin obtained by polycondensation of an aromatic dihydroxy compound represented by the following general formula (4) and a carbonic acid diester represented by the following general formula (4) in the presence of a catalyst: A method for producing the electrophotographic photosensitive member according to claim.

(In the formula (4), ^{A 1} and ^{A 2} each independently optionally carbon atoms 1 may have a substituent
18 aliphatic groups or an aromatic group which may have a substituent is represented. )

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