JP4325010B2 - LAMINATED ELECTROPHOTOGRAPHIC PHOTOSENSOR, METHOD FOR PRODUCING THE SAME, AND METHOD FOR PRODUCING CHARGE TRANSPORT LAYER COATING USED FOR THE SAME - Google Patents

Description

【００６６】
以上の結果により、含まれる過酸化物量が電荷輸送剤に対して０．０２％より少ない電荷輸送層用塗料を用いて得られる本発明の積層型電子写真用感光体（実施例）では、含まれる過酸化物量が電荷輸送剤に対して０．０２％以上の電荷輸送層用塗料を用いて得られる積層型電子写真用感光体よりも半導体レーザのような長波長光に対して良好な感度を示し、残留電位が小さくかつ繰り返し安定性が向上することがわかった。
【００６７】
【発明の効果】
以上説明したように、本発明の積層型電子写真用感光体によれば、導電性支持体上に、少なくとも電荷発生層と電荷輸送層とを積層してなる積層型電子写真用感光体において、前記電荷発生層が、オキソチタニウムフタロシアニン顔料を含有する電荷発生層であり、さらに、前記電荷輸送層が、少なくとも電荷輸送バインダ樹脂、酸化防止剤とテトラヒドロフランを用い形成されたものであり、かつテトラヒドロフランを塗料作成前に蒸留あるいはアルミナとの接触により電荷輸送層を形成する塗料中に含まれるテトラヒドロフランの過酸化物量が電荷輸送剤に対して０．０２％より少なくすることにより、電荷輸送層形成時に過酸化物と電荷発生剤や電荷輸送剤との相互作用が極めて少なく、高感度でしかも残留電位が小さくしかも繰り返し安定性の優れた感光体を提供することができる。
【００６８】
本発明の積層型電子写真用感光体の製造方法によれば、導電性支持体上に、少なくとも電荷発生層と電荷輸送層とをこの順に積層した積層型電子写真用感光体を製造する方法において、前記電荷発生層の形成工程が、オキソチタニウムフタロシアニン顔料の含有層を形成する工程を含み、さらに、前記電荷輸送層の形成工程が、前記工程により得られた電荷発生層上に、少なくとも電荷輸送剤、バインダ樹脂、酸化防止剤を、溶剤としてテトラヒドロフランを用い、かつ含まれる過酸化物量が電荷輸送剤に対して０．０２％より少なくなるように調製された塗料を用いて塗工する工程を含むものとしたことにより、前記した本発明の積層型電子写真用感光体を合理的かつ安定に製造することができる。
【００６９】
本発明の電荷輸送層用塗料の製造方法によれば、その製造工程が、少なくとも電荷輸送剤とバインダ樹脂と酸化防止剤とをテトラヒドロフランに溶解する工程を含み、かつその塗料中に含まれる過酸化物量が電荷輸送剤に対して０．０２％より少なくなるように、用いるテトラヒドロフラン中の過酸化物量が調製されていることにより、前記した本発明の積層型電子写真用感光体を合理的かつ安定に製造することができる。また、その製造工程が、少なくとも電荷輸送剤、バインダ樹脂、酸化防止剤をテトラヒドロフランに溶解する工程と、その塗料中に含まれる過酸化物量が電荷輸送剤に対して０．０２％より少なくなるように、塗料の過酸化物除去工程を含んでいることにより、前記した本発明の積層型電子写真用感光体を合理的かつ安定に製造することができる。
【図面の簡単な説明】
【図１】本発明の実施形態にかかる積層型電子写真用感光体の構成を模式的に示した断面図
【図２】本発明の実施例で使用した浸漬塗工装置を示す図
【符号の説明】
１ 積層型電子写真用感光体
２ 導電性支持体
３ 電荷発生層
４ 電荷輸送層
５ 電荷輸送層用塗料
６ 浸漬塗工装置
７ 被塗工体
８ ポット部
９ 支持体把持装置を備えた可動部
１０ 循環用ポンプ
１１ フィルターユニット[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer electrophotographic photoreceptor used in electrophotographic apparatuses such as copying machines, printers and facsimiles, a method for producing the same, and a method for producing a coating for a charge transport layer that can be used therefor. Laminated electrophotographic photoreceptor capable of maintaining electrophotographic characteristics with high sensitivity and low residual potential and excellent repetitive stability when tetrahydrofuran is used as a solvent of a coating material used for forming a layer, and a method for producing the same The present invention relates to a method for producing a charge transport layer coating material that can be used therefor.
[0002]
[Prior art]
In recent years, the advantages of electrophotographic devices such as high speed, low noise, high image quality, and the ability to record on plain paper have been attracting attention. It is becoming popular. Also, as a recent trend, especially in the field of printers and facsimiles, the form of use has shifted from office use to personal use, and there is a need for further miniaturization, cost reduction, maintenance freeness, etc. Accordingly, with the improvement of image processing technology, there is a demand for an image forming technology with higher resolution and improved image quality.
[0003]
As a photoconductor used in the electrophotographic apparatus, an organic photoconductor containing an organic photoconductive material has been developed and put into practical use because of its advantages such as easy film formation, low cost and non-pollution. Yes. In particular, organic photoreceptors having high sensitivity in a long wavelength region suitable for laser beam printers and facsimiles using a semiconductor laser as an exposure light source are remarkable.
[0004]
Most of the organic photoreceptors in practical use are stacked organic photoreceptors in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are provided on a conductive support. More specifically, the photosensitive layer is formed by forming a thin charge generation layer and a relatively thick charge transport layer thereon. In this case, the charge generation layer has a function of generating carriers. The charge transport layer has a function of transporting carriers, a function of maintaining the charged potential of the photoreceptor, and a function of maintaining the mechanical strength of the photoreceptor.
[0005]
In recent years, as a charge generation material used in the charge generation layer, phthalocyanine, which is highly sensitive in the long wavelength region of the oscillation wavelength of a semiconductor laser, has attracted attention. Especially, among these pigments, laminated electrophotography using oxotitanium phthalocyanine Photoconductors have been put into practical use.
[0006]
There are roughly two methods for forming a charge generation layer using oxotitanium phthalocyanine as a charge generator. One is a method of forming a charge generation layer as a thin layer usually having a thickness of 0.1 to 0.5 μm using a paint in which a certain crystal type oxotitanium phthalocyanine is dispersed in a solvent together with a binder resin. .
[0007]
The other is to deposit oxotitanium phthalocyanine on a conductive support, and then apply a solvent vapor treatment to the deposited oxotitanium phthalocyanine film, or immerse it in a solvent to transform the crystal to form a charge generation layer. It is a method to do. For example, in Japanese Patent Application Laid-Open No. 1-120564, a semiconductor laser is obtained by crystallizing a deposited film obtained by depositing oxotitanium phthalocyanine by immersing it in alcohol for several seconds and using the deposited film as a charge generation layer. It has been reported that a photoreceptor having high sensitivity to light and having excellent photoreceptor characteristics can be obtained.
[0008]
[Problems to be solved by the invention]
As described above, the charge generation layer using oxotitanium phthalocyanine is generally formed by coating a thin film using a paint in which oxotitanium phthalocyanine is dispersed, and forming a deposited film of oxotitanium phthalocyanine. In order to obtain high image quality, the latter method of forming a deposited film of oxotitanium phthalocyanine can easily form a thin film with a uniform concentration and has excellent film quality stability. It is advantageous.
[0009]
On the other hand, as a solvent for forming the charge transport layer, chlorinated organic solvents such as dichloromethane and chloroform have been generally used conventionally. Recently, however, the problem of environmental pollution has been greatly taken up, and it has been necessary to replace the solvent used with a non-chlorine solvent.
[0010]
On the other hand, tetrahydrofuran is suitable as a non-chlorine solvent for reasons such as solubility and coating properties, but has the following disadvantages. That is, tetrahydrofuran is oxidized by contact with air or oxygen to produce a peroxide, which interacts with the charge generating agent oxotitanium phthalocyanine or charge transport agent, and thereby has an electrophotographic characteristic, particularly a residual potential. And adversely affects repeated stability. For example, JP-A-4-191745 discloses that a cyclic ether system containing 400 ppm to 2% by weight of an antioxidant is used as a solvent to prevent the formation of peroxide. However, there is no description on the amount of peroxide and how to deal with peroxide generation, and it is considered that the above-described deterioration of the electrophotographic characteristics occurs due to long-term use.
[0011]
The present invention has been made in view of the above problems, and even when a charge transport layer coating containing tetrahydrofuran is used for forming the charge transport layer, it has high sensitivity to semiconductor laser light and has a residual potential. It is an object of the present invention to provide a multilayer electrophotographic photoreceptor that is small and excellent in repetitive stability, a method for producing the same, and a method for producing a coating material for a charge transport layer that can be used therefor.
[0012]
[Means for Solving the Problems]
  Accordingly, in order to achieve this object, a multilayer electrophotographic photoreceptor according to claim 1 of the present invention is a multilayer electron beam comprising at least a charge generation layer and a charge transport layer laminated on a conductive support. A photographic photoreceptor, wherein the charge generation layer is a charge generation layer containing an oxotitanium phthalocyanine pigment, and the charge transport layer uses at least a charge transport agent, a binder resin, an antioxidant and tetrahydrofuran. Formed,Distilled or mixed with tetrahydrofuran brought into contact with alumina and charge transport agent, binder resin, antioxidantThus, a laminated electrophotographic photoreceptor is obtained.
[0013]
  In addition, the laminated electrophotographic photoreceptor according to claim 2 of the present invention includes:As antioxidant of Claim 1, using what was chosen from phenolic antioxidant or sulfur type antioxidant, or these mixturesIt is a laminated electrophotographic photoreceptor.
[0014]
A laminated electrophotographic photosensitive member according to claim 3 of the present invention is also provided.The production method is a method for producing a laminated electrophotographic photoreceptor in which at least a charge generation layer and a charge transport layer are laminated in this order on a conductive support, wherein the step of forming the charge generation layer comprises oxotitanium phthalocyanine. A step of forming a pigment-containing layer, and the step of forming the charge transport layer uses at least a charge transport agent, a binder resin, an antioxidant and a solvent as a solvent on the charge generation layer obtained by the step. And including a step of coating with a paint prepared using tetrahydrofuran that is distilled or contacted with alumina.Laminated electrophotographic photoreceptorManufacturing methodIt is what.
[0015]
A method for producing a laminated electrophotographic photoreceptor according to claim 4 of the present invention includes:As antioxidant of Claim 3, using what was chosen from phenolic antioxidant or sulfur type antioxidant, or these mixturesThis is a method for producing a laminated electrophotographic photoreceptor.
[0016]
Further, according to claim 5 of the present invention.In the method for producing a charge transport layer coating, the charge transport layer coating production process includes at least a step of dissolving a charge transport agent, a binder resin, and an antioxidant in tetrahydrofuran, and the peroxidation contained in the paint. The amount of peroxide in the tetrahydrofuran is adjusted so that the amount is less than 0.02% with respect to the charge transport agent, and the amount of peroxide in the tetrahydrofuran is adjusted by distillation of tetrahydrofuran or contact with alumina. Of the coating for the charge transport layer by being purified byThis is a manufacturing method.
[0017]
  Further, according to claim 6 of the present invention.The method for producing a charge transport layer coating comprises the following: an antioxidant selected from the group consisting of a phenol-based antioxidant, a sulfur-based antioxidant, or a mixture thereof. paintThis is a manufacturing method.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0024]
FIG. 1 is a cross-sectional view schematically showing the structure of a multilayer electrophotographic photoreceptor according to an embodiment of the present invention. In the figure, 1 is a multilayer electrophotographic photoreceptor, which is a conductive support. The charge generation layer 3 and the charge transport layer 4 are laminated on the body 2 in this order.
[0025]
The conductive support 2 is a base made of a known conductive material, for example, a metal material such as aluminum, or conductive plastic (for example, conductive particles such as carbon are dispersed in an insulating resin such as a phenol resin). A base made of glass coated with a conductive metal compound such as aluminum iodide, copper iodide, chromium oxide, or tin oxide is used. The form of the substrate is not particularly limited, and may be various forms such as a drum shape (pipe shape), a plate shape, and a belt shape.
[0026]
The charge generation layer 3 is formed on the conductive support 2 by dispersing an oxotitanium phthalocyanine pigment in a binder resin, or preferably, the oxotitanium phthalocyanine is deposited on the conductive support 2 in a vacuum, This oxotitanium phthalocyanine deposited film is formed by treating with a solvent, preferably a hydrous solvent.
[0027]
When the charge generation layer is formed by dispersing in a binder resin, various known crystal forms can be used as the oxotitanium phthalocyanine pigment to be used. Moreover, as binder resin to be used, various well-known resin can be used, Preferably a butyral resin etc. are mentioned. A material in which these are sufficiently dispersed in a solvent such as isobutanol using glass beads or the like until they become fine particles is used as the charge generation layer coating material.
[0028]
On the other hand, when an oxotitanium phthalocyanine pigment is used as a vapor deposition film, the higher the purity, the better the oxotitanium phthalocyanine. It is done. Next, the obtained oxotitanium phthalocyanine vapor-deposited film is converted into a predetermined crystal form by immersion treatment or steam treatment with a water-containing solvent or the like.
[0029]
Examples of the solvent used for the water-containing solvent include ether compounds, ester compounds, aromatic hydrocarbons, and the like. Specific examples include tetrahydrofuran, butyl acetate, xylene, anisole and the like. By these treatments, the oxotitanium phthalocyanine vapor-deposited film becomes a charge generation layer with few carrier traps and recombination. Moreover, the mixing ratio of the organic solvent and water of the water-containing organic solvent used for the steam treatment is 100: 1 to 100: 50, preferably 100: 2 to 100: 40, as a volume ratio (organic solvent: water). By setting the volume ratio of the organic solvent and water within these ranges, the photoreceptor using the obtained oxotitanium phthalocyanine vapor-deposited film as the charge generation layer becomes excellent in sensitivity.
[0030]
The film thickness of the charge generation layer containing the oxotitanium phthalocyanine pigment is about 0.03 to 0.5 μm, preferably about 0.1 to 0.2 μm, in view of characteristics. This shows that if the film thickness is too thin, the amount of charge (carrier) generation is small and it is difficult to obtain sufficient sensitivity. If the film thickness is too thick, the dark decay increases and the charging potential decreases. This is because the repeated stability of the sensitivity tends to decrease. That is, if the film thickness is about 0.03 to 0.5 μm, a sufficient amount of generated carriers can be obtained and the dark attenuation can be sufficiently reduced.
[0031]
In the charge transport layer 4, a charge transport agent, a binder resin, and an antioxidant are dissolved in tetrahydrofuran from which peroxide is removed, and the amount of peroxide contained in the charge transport layer coating is 0.02 with respect to the charge transport agent. It is formed by coating the charge generation layer 3 on the charge generation layer 3 by a conventionally known coating method to form a coating film, and drying the coating film.
[0032]
Examples of the method for removing peroxide from tetrahydrofuran include a distillation method and a method of passing through a column packed with alumina powder. The concentration of peroxide in tetrahydrofuran was determined in the same manner as shown in JIS K-9705. Specifically, about 10 g of a sample was weighed to a 0.1 mg unit (Wg), and 50 ml of water was used. Add 1 g of potassium iodide, dissolve potassium iodide, add 5 ml of previously prepared sulfuric acid (1 + 15) and 1 ml of starch solution, mix well for about 5 minutes, and titrate with 0.01 mol / l sodium thiosulfate aqueous solution (Mml) . Hereinafter, the peroxide concentration (%) is obtained by the calculation of 0.00017005 × (M / W) × 100.
[0033]
Examples of the charge transfer agent include heterocyclic compounds such as oxazole, oxadiazole, and pyrazoline, hydrazone compounds, butadiene compounds, stilbene compounds, and various derivatives of these compounds. Specific examples include, for example, 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone, 4-diethylaminobenzaldehyde-N, N-diphenylhydrazone, 1,1-bis (p-diethylaminophenyl) -4. , 4-diphenyl-1,3-butadiene, 4-N, N-diphenylamino-α-phenylstilbene, 4- {N- (p-methoxyphenyl) -N-phenylamino} -α-phenylstilbene, and the like. One or more of these are used. In particular, when both 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone and 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene are used, Alternatively, when 4- {N- (p-methoxyphenyl) -N-phenylamino} -α-phenylstilbene is used, it is possible to form a photosensitive layer having particularly good sensitivity and less deterioration due to ozone. . When both 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone and 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene are used, The mixing ratio of the two is a weight ratio (2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone: 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene). In general, it is preferably in the range of 99: 1 to 30:70. This shows a tendency for the sensitivity to decrease when there is too much 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone, and 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1 This is because, when there is too much 1,3-butadiene, the ozone resistance tends to decrease, and when the blending ratio of both is within the above range, good sensitivity and good ozone resistance can be obtained.
[0034]
Examples of the binder resin include various resins such as polyester, polycarbonate, polysulfone, and polymethyl methacrylate that are soluble in tetrahydrofuran.
[0035]
As the antioxidant, a phenol-based antioxidant and a sulfur-based antioxidant can be used. For example, 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 2 -T-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2-mercaptobenzimidazole, dilauryl-3,3-thiodipropionate, etc. .
[0036]
The composition of the coating is not particularly limited, but generally, the charge transport agent and the binder resin are used such that their weight ratio (charge transport agent: binder resin) is in the range of 60:40 to 40:60. It is dissolved in tetrahydrofuran so that the total solid concentration of the agent and the binder resin is 10 to 40% by weight.
[0037]
The amount of the antioxidant is added to the paint so that the weight ratio is 0.5 to 10% by weight with respect to the total solid content of the charge transport agent and the binder resin.
[0038]
When the amount of peroxide becomes 0.02% or more with respect to the charge transport agent during storage of the charge transport layer coating, the coating is mixed with alumina powder, preferably stirred, and after standing, The powder is separated and used again as a coating for the charge transport layer. The amount of peroxide in the paint is measured in a manner similar to that shown in JISK-9705, as is the concentration of peroxide in tetrahydrofuran. Specifically, about 5 g of the paint is weighed to the nearest 0.1 mg, 50 ml of water is added, and the mixture is stirred and mixed well for about 5 minutes. This is for sufficiently eluting the peroxide incorporated in the resin, and depending on the viscosity of the paint, water may be added after dilution with tetrahydrofuran from which the peroxide has been removed. Thereafter, 1 g of potassium iodide, 5 ml of previously prepared sulfuric acid (1 + 15), and 1 ml of a starch solution were added in the same manner as in the determination of the peroxide concentration in tetrahydrofuran, and the mixture was thoroughly mixed for about 5 minutes. 0.01 mol / l sodium thiosulfate Titrate with an aqueous solution (Mml), and determine the peroxide concentration (%) by the calculation of 0.00017005 × (M / W) × 100.
[0039]
The coating method of the paint is not particularly limited, but a dip coating apparatus 6 having a circulating pump 10 as shown in FIG. 2, a pot portion 8 having a filter unit 11 and a movable portion 9 for gripping the object to be coated 7. Often used. When the coating body 7 is formed by immersing the object 7 on which the charge generation layer 3 is formed in the charge transport layer coating material 5 and pulling it up, a so-called dip coating method is used. A coating film having a large thickness and a uniform thickness can be formed easily and in a short time.
[0040]
The thickness of the charge transport layer 5 is generally several μm to several tens of μm, preferably 15 to 30 μm. By setting the film thickness within such a range, the initial charging potential of the photoreceptor can be set sufficiently high.
[0041]
【Example】
Example 1
Synthesis of oxotitanium phthalocyanine pigments
In a three-necked flask, 1,3-diiminoisoindoline (113 g) was suspended in 1-chloronaphthalene (770 ml), tetra-n-butyl titanate (75 g) was added with stirring, and 195 in a nitrogen atmosphere. Heat at ~ 205 ° C for 4 hours. Thereafter, the mixture was allowed to cool to 130 ° C. and then filtered. The filtered product was washed with 1-chloronaphthalene (100 ml) heated to 100 ° C. and then thoroughly washed with ethanol (1000 ml). The suspension was washed three times with dimethylformamide (500 ml) at 80 ° C. for 1 hour, and then twice with ethanol (500 ml) at 60 ° C. for 1 hour, followed by 50 ° C. And vacuum dried. Next, the obtained pigment was heated under reflux in quinoline (2000 ml) with stirring for 4 hours, allowed to stand overnight, cooled in an ice-water bath for 1 hour, and filtered off. After thoroughly washing with ethanol, vacuum drying was performed at 50 ° C. for 10 hours and at 100 ° C. for 10 hours. Yield was 75 g.
[0042]
Next, in order to purify it by sublimation, about 10 g of the obtained oxotitanium phthalocyanine was spread on a quartz boat, placed in a quartz tube, and evacuated with a vacuum pump until the inside pressure of the tube reached about 1 Pascal. Subsequently, the quartz boat placed in the quartz tube was placed in an electric furnace while being positioned at the center of heating, and heated at a temperature of about 450 ° C. for 30 hours while being evacuated by a vacuum pump. Thereafter, after the temperature was lowered to room temperature, the glossy oxotitanium phthalocyanine deposited on the inner surface of the quartz tube in the vicinity of the quartz boat was collected to obtain about 7 g of oxotitanium phthalocyanine.
[0043]
Manufacture of multilayer photoconductors
3 × 10 of the oxotitanium phthalocyanine obtained as described above^-3It vapor-deposited so that it might become a thickness of 0.1 micrometer on the aluminum plate under the vacuum of Pa. This deposited film was immersed in methanol at room temperature for 20 seconds. By this immersion treatment, the maximum absorption wavelength shifted to the long wavelength side.
[0044]
Next, the methanol-treated vapor-deposited film was exposed for 30 minutes in the vapor of a hydrous solvent composed of tetrahydrofuran-water (volume ratio 100: 10).
[0045]
Next, 18 parts by weight of 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone and 1,1-bis are formed on the charge generation layer formed of the oxotitanium phthalocyanine vapor deposition film thus obtained. (P-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene 2 parts by weight, polycarbonate resin (manufactured by Mitsubishi Gas Chemical Industries, Ltd., trade name Iupilon Z-300), 2 parts as an antioxidant 6-di-t-butyl-p-cresol (manufactured by Sumitomo Chemical Co., Ltd., trade name Sumilyzer BHT) 2 parts by weight, freshly distilled and purified 115 parts by weight of tetrahydrofuran, and dip coating of FIG. Using the processing apparatus, the charge transport layer was provided so that the film thickness after drying was 20 μm, and the photoreceptor was completed.
[0046]
The amount of peroxide in the resulting charge transport layer coating was tested by the above-described method similar to that shown in JIS K-9705, but the amount of peroxide was not detected (0%). ).
[0047]
Next, the electrostatic characteristics of the photoconductor were evaluated using a photoconductor drum measurement system (CYNTHIA55 manufactured by Gentec Corporation).
[0048]
In the evaluation, the corona current and the grid voltage are adjusted so that the initial charging potential V0 (V) when the photosensitive member is negatively charged in the dark is 500 V or more, and the surface potential after 2 seconds of dark decay is V2 (V ), The charge retention after 2 seconds of dark decay was measured as DDR2 (%), and subsequently 0.7 μJ / cm having a peak at 780 nm.²Irradiation with monochromatic light with energy of s for 5 seconds, exposure amounts at which the surface potential becomes 1 / 2V2 and 1 / 5V2 are E1 / 2 and E1 / 5 (μJ / cm, respectively)²) And the surface potential after 5 seconds of exposure was measured as the residual potential VR (V). The results are shown in (Table 1).
[0049]
In addition, the sample prepared above was also subjected to 1000 repetition tests. After the repetition, similar measurements were performed to evaluate the repeated stability of electrostatic characteristics (sensitivity and charging characteristics). The results are shown in (Table 1).
[0050]
(Example 2)
Instead of exposing the oxotitanium phthalocyanine vapor-deposited film of Example 1 to a methanol-treated vapor of water-containing solvent consisting of tetrahydrofuran-water (volume ratio 100: 10) for 30 minutes, the vapor-deposited film was subjected to n-butyl acetate-water (volume ratio). In the same manner as in Example 1, except that the vapor treatment was performed for 30 minutes for only 100: 10), the electrostatic characteristics were evaluated in the same manner as in Example 1. The results are shown in (Table 1).
[0051]
(Example 3)
Instead of exposing the oxotitanium phthalocyanine vapor-deposited film of Example 1 to a methanol-treated vapor of water-containing solvent consisting of tetrahydrofuran-water (volume ratio 100: 10) for 30 minutes, the vapor-deposited film was m-xylene-water (volume ratio). In the same manner as in Example 1, except that the vapor treatment was performed for 30 minutes for only 100: 10), the electrostatic characteristics were evaluated in the same manner as in Example 1. The results are shown in (Table 1).
[0052]
(Example 4)
Instead of the steam treatment with the water-containing organic solvent consisting of m-xylene-water in Example 3, Example 3 was used except that it was left in the steam of the water-containing solvent consisting of anisole-water (100: 10 by volume) for 30 minutes. A photoconductor was prepared in the same manner as in Example 1, and the electrostatic characteristics were evaluated in the same manner as in Example 1. The results are shown in (Table 1).
[0053]
(Example 5)
Instead of using the deposited film of the oxotitanium phthalocyanine pigment shown in Example 1 as the charge generation layer, a pigment dispersion film was used. That is, 15 g of the quinoline refluxed and ethanol-washed pigment before sublimation purification obtained in Example 1 was gradually added to 300 g of sulfuric acid while stirring in an ice water bath. The mixture is further stirred for 1 hour, filtered with suction through a glass filter, and the filtrate is gradually poured into 5 l of ice water while stirring. The resulting precipitate is filtered off with suction, and washed thoroughly with distilled water until the filtrate becomes acidic to almost neutral. Next, this acid-treated oxotitanium phthalocyanine in a glass filter is placed in a wet state in a 500 ml three-necked flask and refluxed with 300 ml of acetonitrile with heating and stirring for 20 hours. After cooling to room temperature, it is separated with a centrifuge. This was washed with 300 ml each of cyclohexanone with hot suspension (60 ° C., 1 hour) with stirring, and finally twice with 300 ml of ethanol (60 ° C., 1 hour). Then vacuum dry. The obtained oxotitanium phthalocyanine has X-ray diffraction spectrum Bragg angles (2θ) of 6.8 °, 15.4 °, 23.3 °, 25.2 °, 27.1 °,
It showed a strong diffraction peak at 28.5 °.
[0054]
3.2 g of the obtained pigment, 1.6 g of polyvinyl butyral resin (trade name ESREC BL-1 manufactured by Sekisui Chemical Co., Ltd.), 48 mg of hydrophobized silica (trade name CABOSILS TS-720 manufactured by Cabot Corporation), 112 g of isobutanol and glass Place in a glass bottle with 120 g of beads (1 mm diameter) and disperse for 15 hours in a paint shaker.
[0055]
The obtained paint was applied on an aluminum plate so that the film thickness after drying was 0.1 μm, and dried at 100 ° C. for 1 hour.
[0056]
Next, on the charge generation layer thus obtained, a charge transport layer is provided using the same charge transport layer coating material as used in Example 1 to prepare a photoconductor. Similarly, electrostatic characteristics were evaluated. The results are shown in (Table 1).
[0057]
(Example 6)
18 parts by weight of 2-methyl-4-dibenzylaminobenzaldehyde-N, N-diphenylhydrazone of Example 1 and 2 weights of 1,1-bis (p-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene Example 1 except that 20 parts by weight of 4- {N- (p-methoxyphenyl) -N-phenylamino} -α-phenylstilbene was used as the charge transport agent instead of the parts. A photoconductor was prepared in the same manner, and electrostatic characteristics were evaluated in the same manner as in Example 1. The results are shown in (Table 1).
[0058]
(Example 7)
When the distilled tetrahydrofuran of Example 1 was allowed to stand for 10 days and the peroxide concentration in tetrahydrofuran was measured by the test method of JIS K-9705, it increased to 0.006%. When this tetrahydrofuran was passed through an open column filled with 50 g of alumina powder and the amount of peroxide was examined again, no peroxide was detected.
[0059]
Using the above-mentioned tetrahydrofuran through an alumina-filled column, a paint was formed in the same manner as in Example 1, a photoreceptor was prepared, and electrostatic characteristics were evaluated. The results are shown in (Table 1). Of course, no peroxide was detected in the paint.
[0060]
(Example 8)
The charge transport layer paint used in Example 1 could not detect the amount of peroxide immediately after the paint was prepared, but the amount of peroxide in the paint after standing for 3 months was determined according to the test method according to JIS K-9705. 0.02% was shown with respect to.
[0061]
15 g of alumina powder was added to 120 g of this coating material, and the mixture was stirred for 30 minutes. After standing for 1 hour, the supernatant was filtered under pressure. When the amount of peroxide was examined again for the filtrate, no peroxide was detected.
[0062]
A photoconductor was prepared in the same manner as in Example 1 using the charge transport layer coating treated with alumina powder, and the electrostatic characteristics were evaluated. The results are shown in (Table 1).
[0063]
(Comparative Example 1)
Tetrahydrofuran containing 0.006% of the peroxide of Example 7 was passed through an alumina-filled column and formed into a paint in the same manner as in Example 1, a photoconductor was prepared, and electrostatic characteristics were evaluated. The results are shown in (Table 1). At this time, the peroxide concentration in the paint measured by the test method of JIS K-9705 showed 0.02% with respect to the charge transport agent.
[0064]
(Comparative Example 2)
Instead of using the charge transport layer coating material treated with the alumina powder of Example 8, the photoconductor was prepared in the same manner as in Example 1 using the coating material after being left for 3 months without treatment. The electrostatic characteristics were evaluated. The results are shown in (Table 1).
[0065]
[Table 1]

[0066]
Based on the above results, the layered electrophotographic photoreceptor of the present invention (Example) obtained by using the charge transport layer coating material containing less than 0.02% of the peroxide contained in the charge transport agent is included. Better sensitivity to long-wavelength light such as a semiconductor laser than a laminated electrophotographic photoreceptor obtained by using a coating for a charge transport layer having a peroxide amount of 0.02% or more with respect to the charge transport agent It was found that the residual potential is small and the stability is improved repeatedly.
[0067]
【The invention's effect】
  As described above, according to the laminated electrophotographic photoreceptor of the present invention, in the laminated electrophotographic photoreceptor formed by laminating at least a charge generation layer and a charge transport layer on a conductive support, The charge generation layer is a charge generation layer containing an oxotitanium phthalocyanine pigment, and the charge transport layer is formed using at least a charge transport binder resin, an antioxidant and tetrahydrofuran; andBy making the amount of peroxide of tetrahydrofuran contained in the paint forming the charge transport layer by distillation or contact with alumina before making the paint less than 0.02% with respect to the charge transport agentIn addition, it is possible to provide a photoconductor with extremely little interaction between the peroxide and the charge generating agent or charge transporting agent when forming the charge transporting layer, high sensitivity, low residual potential, and excellent repeatability.
[0068]
According to the method for producing a laminated electrophotographic photoreceptor of the present invention, in the method for producing a laminated electrophotographic photoreceptor in which at least a charge generation layer and a charge transport layer are laminated in this order on a conductive support. The step of forming the charge generation layer includes a step of forming a layer containing an oxotitanium phthalocyanine pigment, and the step of forming the charge transport layer includes at least charge transport on the charge generation layer obtained by the step. A step of applying an agent, a binder resin, an antioxidant, using tetrahydrofuran as a solvent, and a paint prepared such that the amount of peroxide contained is less than 0.02% with respect to the charge transport agent. By including, the above-described multilayer electrophotographic photoreceptor of the present invention can be manufactured reasonably and stably.
[0069]
According to the method for producing a paint for a charge transport layer of the present invention, the production process includes at least a step of dissolving a charge transport agent, a binder resin, and an antioxidant in tetrahydrofuran, and the peroxidation contained in the paint. By preparing the amount of peroxide in tetrahydrofuran to be used so that the amount is less than 0.02% with respect to the charge transfer agent, the above-described laminated electrophotographic photoreceptor of the present invention can be made rational and stable. Can be manufactured. Further, the manufacturing process includes a step of dissolving at least the charge transport agent, the binder resin, and the antioxidant in tetrahydrofuran, and the amount of peroxide contained in the paint is less than 0.02% with respect to the charge transport agent. In addition, by including a peroxide removal step of the coating material, the above-described laminated electrophotographic photoreceptor of the present invention can be manufactured reasonably and stably.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing the configuration of a multilayer electrophotographic photoreceptor according to an embodiment of the present invention.
FIG. 2 is a diagram showing a dip coating apparatus used in an embodiment of the present invention.
[Explanation of symbols]
1. Laminate type electrophotographic photoreceptor
2 Conductive support
3 Charge generation layer
4 Charge transport layer
5 Paint for charge transport layer
6 Dip coating equipment
7 Object to be coated
8 pots
9 Movable part with support gripping device
10 Circulation pump
11 Filter unit

Claims (6)

In a laminated electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer stacked on a conductive support, the charge generation layer is a charge generation layer containing an oxotitanium phthalocyanine pigment, The charge transport layer is formed using at least a charge transport agent, a binder resin, an antioxidant, and tetrahydrofuran, and is mixed with tetrahydrofuran or a charge transport agent, a binder resin, and an antioxidant brought into contact with distillation or alumina. A laminated electrophotographic photoreceptor characterized in that: 2. The laminated electrophotographic photoreceptor according to claim 1, wherein the antioxidant is selected from a phenolic antioxidant, a sulfur-based antioxidant, or a mixture thereof . In the method for producing a laminated electrophotographic photoreceptor in which at least a charge generation layer and a charge transport layer are laminated in this order on a conductive support, the charge generation layer forming step comprises a layer containing an oxotitanium phthalocyanine pigment And the step of forming the charge transport layer comprises, on the charge generation layer obtained by the above step, at least a charge transport agent, a binder resin, an antioxidant, and distilled or contacted with alumina as a solvent. A method for producing a laminated electrophotographic photoreceptor , comprising a step of coating using a paint prepared using tetrahydrofuran . 4. The multilayer electrophotographic photoreceptor according to claim 3, wherein the antioxidant is selected from a phenolic antioxidant, a sulfur-based antioxidant, or a mixture thereof . Production method. In the method for producing a charge transport layer coating for use in a laminated electrophotographic photoreceptor, the process for producing the charge transport layer paint includes a step of dissolving at least a charge transport agent, a binder resin, and an antioxidant in tetrahydrofuran, And the amount of peroxide in the tetrahydrofuran is adjusted so that the amount of peroxide contained in the paint is less than 0.02% with respect to the charge transfer agent,
The method for producing a coating material for a charge transport layer, wherein the amount of the peroxide in the tetrahydrofuran is prepared by purification by distillation of tetrahydrofuran or contact with alumina . The antioxidant, phenolic antioxidant or sulfur antioxidant, or 請 Motomeko 5 SL placement of the charge transport layer coating you characterized in that selected from among mixtures thereof Manufacturing method.

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