JP2009163053A - Method of inspecting electrophotographic photoreceptor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of inspecting an electrophotographic photoreceptor capable of reducing a measurement error and measuring the thickness of an undercoating layer at a low cost, and to provide a method of manufacturing the electrophotographic photoreceptor. <P>SOLUTION: The method of detecting the electrophotographic photoreceptor prepared by laminating the undercoating layer containing inorganic particles, and a photosensitive layer containing a charge generation agent, a charge transporting agent and a binder resin is characterized in that reflection absorbance of the undercoating layer at a wavelength of 400 nm or less is measured. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inspection method and a manufacturing method for an electrophotographic photosensitive member.

As an electrophotographic photoreceptor provided in an image forming apparatus, one in which a photosensitive layer is laminated on a conductive substrate made of aluminum or the like is known. In such an electrophotographic photosensitive member, it was necessary to insulate it to such an extent that leakage was suppressed.
In recent years, therefore, an electrophotographic photosensitive member has been proposed in which an undercoat layer is interposed between a conductive substrate and a photosensitive layer.

  The electrophotographic photoreceptor is usually obtained by sequentially coating and drying each coating solution for forming the undercoat layer and the photosensitive layer on a conductive substrate. Since the thickness of each layer affects the characteristics of the electrophotographic photosensitive member, it was necessary to inspect the electrophotographic photosensitive member by accurately measuring the thickness when manufacturing the electrophotographic photosensitive member.

  Although the thickness of each layer can be controlled to a certain degree by a coating apparatus, it may slightly vary depending on environmental conditions. In continuous production, it is required to produce an electrophotographic photosensitive member in which an undercoat layer and a photosensitive layer having a constant thickness are always formed on a conductive substrate. Therefore, the thickness of each layer is measured more accurately. Need to manage. In particular, since the undercoat layer in contact with the conductive substrate is formed by first coating in the coating process, it is important to measure and manage the thickness of the undercoat layer.

As a method for measuring the thickness of the undercoat layer, a method using an eddy current film thickness meter is conventionally known.
However, the method using an eddy current film thickness meter tends to cause measurement errors.
Therefore, as a method for measuring the undercoat layer more accurately, for example, Patent Document 1 discloses a method for manufacturing an electrophotographic photoreceptor having a step of measuring the thickness of the undercoat layer by an optical interference method. .
JP-A-4-336540

  However, as described in Patent Document 1, in the method of measuring the undercoat layer by the optical interference method, the measurement error is reduced, but an expensive apparatus is required for the measurement, so that the cost is easily increased.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to realize an inspection method and a manufacturing method of an electrophotographic photoreceptor capable of reducing measurement errors and measuring the thickness of the undercoat layer at low cost.

  The method for inspecting an electrophotographic photoreceptor of the present invention is an electron in which an undercoat layer containing inorganic particles, a photosensitive layer containing a charge generator, a charge transport agent, and a binder resin are sequentially laminated on a conductive substrate. In the method for inspecting a photographic photoreceptor, before forming the photosensitive layer, the reflection absorbance at a wavelength of 400 nm or less is measured for the undercoat layer.

  In addition, the electrophotographic photoreceptor inspection method of the present invention is a method in which an undercoat layer containing inorganic particles, a photosensitive layer containing a charge generating agent, a charge transporting agent, and a binder resin are sequentially laminated on a conductive substrate. After removing the photosensitive layer from the electrophotographic photosensitive member with a solvent insoluble in the undercoat layer, the reflection absorbance at a wavelength of 400 nm or less is measured for the undercoat layer.

Here, the inorganic particles are preferably titanium oxide.
Moreover, it is preferable that the said titanium oxide is a rutile type.
Furthermore, it is preferable that the average primary particle diameter of the titanium oxide is 100 nm or less.

  The method for producing an electrophotographic photosensitive member of the present invention is an electron in which an undercoat layer containing inorganic particles, a photosensitive layer containing a charge generator, a charge transport agent, and a binder resin are sequentially laminated on a conductive substrate. In the method for producing a photographic photoreceptor, before forming the photosensitive layer, a coating solution for forming the photosensitive layer is applied on the undercoat layer whose reflection absorbance at a wavelength of 400 nm or less is measured.

  In the method for producing an electrophotographic photoreceptor of the present invention, an undercoat layer containing inorganic particles, a photosensitive layer containing a charge generating agent, a charge transporting agent, and a binder resin are sequentially laminated on a conductive substrate. In the method for producing an electrophotographic photosensitive member, the photosensitive layer is removed from the electrophotographic photosensitive member with a solvent insoluble in the undercoat layer, and the undercoat layer is reflected at a wavelength of 400 nm or less. After measuring the absorbance, a coating solution for forming a photosensitive layer is applied to re-form the photosensitive layer.

According to the electrophotographic photosensitive member inspection method of the present invention, the measurement error can be reduced and the thickness of the undercoat layer can be measured at a low cost.
Further, according to the present invention, a high-quality electrophotographic photoreceptor can be produced.

Hereinafter, the present invention will be described in detail.
[Electrophotographic photoreceptor]
In the present invention, an electrophotographic photosensitive member to be inspected has an undercoat layer and a photosensitive layer sequentially laminated on a conductive substrate.

<Conductive substrate>
Examples of the material of the conductive substrate include metals such as iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass, and the like. An oxide film formed by oxidation treatment; a plastic material on which the metal is deposited or laminated; a glass coated with aluminum iodide, tin oxide, indium oxide, etc .; a plastic material in which conductive fine particles such as carbon black are dispersed Etc.
Examples of the shape of the conductive substrate include a sheet shape and a drum shape. The shape of the conductive support may be appropriately determined according to the structure of the image forming apparatus.
The surface of the conductive substrate may be roughened. Thereby, generation | occurrence | production of an interference fringe can be prevented. Examples of the surface roughening treatment include etching, anodizing, wet blasting, sand blasting, rough cutting, and centerless cutting.

<Underlayer>
The undercoat layer contains inorganic particles. By containing the inorganic particles, an increase in resistance can be suppressed by flowing a current smoothly when the electrophotographic photosensitive member is exposed while suppressing the occurrence of leakage.
Examples of the inorganic particles include metals and metal oxides. Specific examples include aluminum, iron, copper, titanium oxide, silica, alumina, zirconium oxide, tin oxide, zinc oxide, and indium oxide. Among these, titanium oxide is preferable. In particular, rutile type titanium oxide is preferable from the viewpoint of imparting appropriate insulating properties.

  Titanium oxide preferably has an average primary particle size of 100 nm or less, more preferably 10 to 50 nm. When the average primary particle diameter exceeds 100 nm, the undercoat layer tends to become cloudy. As a result, the light is likely to be diffusely reflected, so that it is difficult for light to pass through to the inside of the undercoat layer. For this reason, even if the reflection absorbance of the undercoat layer is measured, only the vicinity of the surface is measured, so that it is difficult to accurately measure the reflection absorbance.

  In addition, as titanium oxide, one that is surface-treated with alumina and silica and further surface-treated with silicone or the like may be used.

The undercoat layer contains a binder resin in addition to the inorganic particles described above.
A known binder resin can be used as the binder resin. Specifically, polycarbonate resin such as bisphenol Z type, bisphenol ZC type, bisphenol C type, bisphenol A type, polyarylate resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer , Acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, Thermoplastic resins such as alkyd resin, polyamide resin, polyurethane resin, polysulfone resin, diallyl phthalate resin, ketone resin, polyvinyl acetal resin, polyvinyl butyral resin, polyether resin; silicone resin, epoxy resin, phenol resin Lumpur resins, urea resins, thermosetting resins such as melamine resin, epoxy acrylate, urethane - photocurable resins such as acrylate. Binder resin may be used individually by 1 type, and may use 2 or more types together.

The thickness of the undercoat layer is preferably from 0.1 to 10 μm, more preferably from 0.5 to 5 μm.
10-1000 mass parts is preferable with respect to 100 mass parts of binder resin, and, as for content of an inorganic particle in an undercoat layer, 30-400 mass parts is more preferable.

<Photosensitive layer>
The photosensitive layer contains a charge generator, a charge transport agent, and a binder resin.
A known charge generating agent can be used as the charge generating agent. Specifically, phthalocyanine pigments, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, pyrylium Organic photoconductors such as pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments; selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, amorphous silicon, etc. An inorganic photoconductive agent etc. are mentioned. A charge generating agent may be used individually by 1 type, and may use 2 or more types together.

When the electrophotographic photosensitive member is provided in a digital optical image forming apparatus such as a laser beam printer or a facsimile using a light source such as a semiconductor laser, a photosensitive member having sensitivity in a wavelength region of 700 nm or more is required. A phthalocyanine pigment is preferably used. Examples of the phthalocyanine pigment include metal-free phthalocyanine (τ type or X type), titanyl phthalocyanine (α type or Y type), hydroxygallium phthalocyanine (V type), chlorogallium phthalocyanine (II type), and the like.
In addition, when an electrophotographic photosensitive member is provided in an analog optical image forming apparatus such as an electrostatic copying machine using a white light source such as a halogen lamp, a photosensitive member having sensitivity in the visible region is required. Perylene pigments and bisazo pigments are preferably used.

Examples of the charge transport agent include a hole transport agent and an electron transport agent.
The electrophotographic photosensitive member is selected as a positive or negative charge type depending on the type of charge transport agent used in the charge transport layer. For example, when a hole transporting agent is used as the charge transporting agent for the charge transporting layer, the electrophotographic photosensitive member is negatively charged. In this case, the charge generation layer may contain an electron transport agent.

  As the hole transport agent, a known hole transport agent can be used. Specifically, benzidine compounds, phenylenediamine compounds, naphthylenediamine compounds, phenanthrylenediamine compounds, oxadiazole compounds, styryl compounds, carbazole compounds, pyrazoline compounds, hydrazone compounds, tri Phenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, butadiene compounds, pyrene-hydrazone compounds, acrolein compounds Compounds, carbazole-hydrazone compounds, quinoline-hydrazone compounds, stilbene compounds, stilbene-hydrazone compounds, diphenylenediamine compounds, and the like.A hole transport agent may be used individually by 1 type, and may use 2 or more types together.

  A known electron transport agent can be used as the electron transport agent. Specifically, quinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7-tetranitro-9-fluorenone derivatives, dinitroanthracene derivatives, dinitroacridine derivatives, nitroantharaquinone derivatives , Dinitroanthraquinone derivatives, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, etc. . An electron transfer agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  As the binder resin, one or more of the binder resins exemplified above in the description of the undercoat layer can be selected and used.

The photosensitive layer may contain known additives as long as the electrophotographic characteristics are not affected. Examples of additives include antioxidants, light stabilizers, radical scavengers, singlet quenchers, deterioration inhibitors such as ultraviolet absorbers, softeners, plasticizers, surface modifiers, extenders, thickeners, Examples include dispersion stabilizers, waxes, acceptors, donors, and the like.
Examples of the antioxidant include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroidanones and their derivatives, organic sulfur compounds, and organic phosphorus compounds.

The photosensitive layer may have a single layer structure, or a multilayer structure having a charge generation layer containing a charge generation agent and a charge transport layer containing a charge transfer agent.
Here, the multilayered photosensitive layer will be specifically described.

(Charge generation layer)
The charge generation layer includes a charge generation agent and a binder resin. In addition, a known additive may be contained as long as the electrophotographic characteristics are not adversely affected.
As the charge generating agent, binder resin, and additive, one or more selected from the charge generating agent, binder resin, and additive exemplified above can be selected and used.

  When the hole transport agent is contained in the charge transport layer described later, the charge generation layer may contain an electron transport agent, and when the charge transport layer contains an electron transport agent, the charge generation layer contains May contain a hole transporting agent.

The content of the charge generation agent in the charge generation layer is preferably 5 to 1000 parts by mass, more preferably 30 to 500 parts by mass with respect to 100 parts by mass of the binder resin.
The thickness of the charge generation layer is preferably from 0.01 to 5 μm, and more preferably from 0.1 to 3 μm.

(Charge transport layer)
The charge transport layer includes a charge transport agent and a binder resin. In addition, a known additive may be contained as long as the electrophotographic characteristics are not adversely affected.
As the charge transport agent, the binder resin, and the additive, one or more kinds can be selected and used from the charge transport agents, binder resins, and additives exemplified above.

When a hole transporting agent is contained as a charge transporting agent, a negatively chargeable electrophotographic photoreceptor is obtained. On the other hand, when an electron transport agent is contained as a charge transport agent, a positively chargeable electrophotographic photosensitive member is obtained.
When the hole transport agent is contained in the charge transport layer, the content of the hole transport agent is preferably 10 to 500 parts by mass and more preferably 25 to 200 parts by mass with respect to 100 parts by mass of the binder resin.
When the electron transport agent is contained in the charge transport layer, the content of the electron transport agent is preferably 5 to 200 parts by weight, and more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
The thickness of the charge transport layer is preferably 2 to 100 μm, and more preferably 5 to 50 μm.

In addition, when a photosensitive layer is a single layer structure, 0.1-50 mass parts is preferable with respect to 100 mass parts of binder resin, and 0.5-30 mass parts is more preferable.
20-500 mass parts is preferable with respect to 100 mass parts of binder resin, and, as for content of a hole transport agent, 30-200 mass parts is more preferable.
5-100 mass parts is preferable with respect to 100 mass parts of binder resins, and, as for content of an electron transport agent, 10-80 mass parts is more preferable.
The thickness of the photosensitive layer is preferably 5 to 100 μm, more preferably 10 to 50 μm.

[Inspection method]
In the method for inspecting an electrophotographic photoreceptor of the present invention, before forming the photosensitive layer, the reflection absorbance at a wavelength of 400 nm or less is measured for the undercoat layer.
In the wavelength region of 400 nm or less, there is absorption of inorganic particles such as titanium oxide. Therefore, by incorporating inorganic particles in the undercoat layer, the reflection absorbance at 400 nm or less can be measured for the undercoat layer.

  In the present invention, it is preferable to measure the reflection absorbance of the undercoat layer using a spectrocolorimeter from the viewpoint that the reflection absorbance of the undercoat layer can be measured in a state formed on the conductive substrate. As the spectrocolorimeter, for example, “CM-2500d” manufactured by Konica Minolta, Inc. can be used.

  The degree of measurement error in the measurement of reflection absorbance can be determined by performing measurement a plurality of times and obtaining the average value and standard deviation from the results. That is, the smaller the standard deviation value, the smaller the error. A value obtained by dividing the standard deviation by the average value is an index of the degree of variation in the measurement results. The smaller this value, the smaller the variation. It should be noted that it is sufficient to perform the measurement about 20 times.

The reflection absorbance measurement has a smaller standard deviation value than the measurement using an eddy current film thickness meter. Therefore, the method of inspecting the electrophotographic photosensitive member by measuring the reflection absorbance can reduce the measurement error. The reflection absorbance can be measured easily and inexpensively.
By the way, normally, a measurement error tends to occur as the film thickness decreases. This is particularly noticeable when the actual film thickness is measured and managed using an eddy current film thickness meter or the like. However, according to the present invention, the actual film thickness is not measured but managed by measuring the reflection absorbance of the undercoat layer, so that it can be accurately measured regardless of the thickness of the undercoat layer.
The value of the reflected absorbance does not represent the actual thickness of the undercoat layer, but it is possible to measure the reflected absorbance by preparing a calibration curve in advance with the thickness of the undercoat layer and the reflected absorbance value. The thickness of the undercoat layer can be determined from the result.

Therefore, according to the present invention, since the measurement error can be reduced and the thickness of the undercoat layer can be measured at a low cost, the thickness of the undercoat layer can be more accurately determined particularly in the continuous production of an electrophotographic photosensitive member. Measure and manage.
In addition, as a result of the inspection, if the thickness of the undercoat layer is within the acceptable range, only the one having a more optimal thickness is subjected to the next step (ie, the step of forming a photosensitive layer on the undercoat layer). Therefore, it is possible to feed back the remaining ones, so that a higher quality electrophotographic photosensitive member can be obtained.

In the present invention, after removing the photosensitive layer from the electrophotographic photoreceptor having the photosensitive layer formed on the undercoat layer, the reflection absorbance at a wavelength of 400 nm or less can be measured for the undercoat layer.
Normally, an electrophotographic photoreceptor is damaged by toner as it is used. Since damage is more likely to occur closer to the surface, the electrophotographic photosensitive member can be reproduced by re-forming the photosensitive layer. As described above, when the reflection absorbance is measured at a wavelength of 400 nm or less for the undercoat layer after the photosensitive layer is removed, the optimum thickness of the undercoat layer is not optimal for the step of forming the photosensitive layer. Can be easily determined as a step of feeding back (that is, a step of re-forming the undercoat layer so as to have an optimum thickness), so that a high-quality electrophotographic photosensitive member can be obtained even when the electrophotographic photosensitive member is reproduced be able to.

When removing the photosensitive layer, it is preferable to use a solvent in which the undercoat layer is insoluble. Examples of such a solvent include toluene, tetrahydrofuran (THF), o-xylene, m-xylene, 1,3-dioxolane, 1,4-dioxolane and the like.
The photosensitive layer can be removed by the following method, for example. That is, the surface of the electrophotographic photosensitive member is rubbed with a cloth soaked with toluene, and the photosensitive layer is removed. Then, the photosensitive layer is immersed in THF, and then shower washed with THF to remove the photosensitive layer.

[Production method]
In the electrophotographic photosensitive member, a coating solution for forming a photosensitive layer is applied on the undercoat layer whose reflection absorbance at a wavelength of 400 nm or less is measured by the inspection method described above, and the photosensitive layer is formed on the undercoat layer. It is manufactured by.
Here, the method for producing the electrophotographic photosensitive member of the present invention will be specifically described.

First, a coating solution (undercoat layer coating solution) in which each component contained in the undercoat layer is dissolved or dispersed in a solvent is applied onto a conductive substrate and dried to form an undercoat layer.
Solvents include alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; dichloromethane, dichloroethane, chloroform, Halogenated hydrocarbons such as carbon tetrachloride and chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, propylene glycol monomethyl ether, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone and cyclohexanone; ethyl acetate and methyl acetate And esters such as dimethylformaldehyde, dimethylformamide, and dimethyl sulfoxide. A solvent may be used individually by 1 type and may be used in mixture of 2 or more types.

Examples of the coating method include known methods such as dip coating, spray coating, spin coating, and bar coating.
Examples of the drying device include a high-temperature dryer and a vacuum dryer. The drying temperature is preferably 60 to 150 ° C.

Next, the reflection absorbance of the undercoat layer is measured by the method described above.
If it is determined as acceptable, a coating solution (photosensitive layer coating solution) in which each component contained in the photosensitive layer is dissolved or dispersed in a solvent is applied onto the undercoat layer and dried to form a photosensitive layer. To do. In order to improve the dispersibility of each component and the smoothness of the photosensitive layer surface, a surfactant, a leveling agent, or the like may be added to the coating solution (photosensitive layer coating solution).
As a solvent, 1 or more types can be selected and used from the solvent illustrated previously in description of the coating liquid for undercoat layers. Moreover, the coating method, the drying apparatus, and the drying temperature are the same as in the case of forming the undercoat layer.
In the case where the photosensitive layer has a multilayer structure, each coating solution (charge generation layer coating solution and charge transport layer coating solution) in which the components contained in each layer are dissolved or dispersed in a solvent is added to the lower layer. It is coated on top and dried to form each layer, which is a photosensitive layer. The solvent, coating method, drying apparatus, and drying temperature are the same as in the case of forming the undercoat layer. Further, the order of stacking the charge generation layer and the charge transport layer is not particularly limited.

  On the other hand, as a result of measuring the reflection absorbance of the undercoat layer, when it is determined to be unacceptable, the reflection absorbance is measured again by feeding back and re-forming the undercoat layer. This operation is performed until it passes, and for those that pass, a photosensitive layer is formed on the undercoat layer.

  In addition, when the photosensitive layer on the undercoat layer is damaged, such as uneven thickness or scratches, or when the life of the electrophotographic photosensitive member is reduced due to long-term use, the photosensitive layer is After removing the photosensitive layer from the formed electrophotographic photoreceptor with a solvent insoluble in the undercoat layer, and measuring the reflection absorbance at a wavelength of 400 nm or less for the undercoat layer, the thickness of the undercoat layer is optimal. Since it is possible to easily determine that the process is to re-form the photosensitive layer and that which is not optimal is the feedback process, a high-quality electrophotographic photoreceptor can be obtained even when the electrophotographic photoreceptor is manufactured again.

  The electrophotographic photoreceptor thus obtained is of high quality because the thickness of the undercoat layer is accurately measured and manufactured using the one determined to be the optimum thickness as the photoreceptor.

  As described above, according to the present invention, the thickness of the undercoat layer can be accurately measured and managed by measuring the reflection absorbance at a wavelength of 400 nm or less. Therefore, a high quality electrophotographic photosensitive member can be produced.

  The image forming apparatus provided with the electrophotographic photoreceptor obtained by the present invention has good photoreceptor characteristics and can form an image with excellent quality. Examples of such an image forming apparatus include a copying machine, a facsimile machine, and a laser beam printer.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to a following example.
[Example 1]
After surface treatment with alumina and silica, 2.5 parts by mass of titanium oxide (“TMT-02”, number average primary particle diameter 10 nm, manufactured by Teika Co., Ltd.) surface-treated with methylhydrogenpolysiloxane while being wet-dispersed, 1 part by mass of a polymerized polyamide resin (manufactured by Daicel Degussa, “X1010”) was dispersed in 20 parts by mass of ethanol and 5 parts by mass of butanol for 5 hours using a bead mill to prepare an undercoat layer coating solution.
After filtering the obtained coating solution for undercoat layer with a 5 μm filter, on an aluminum cutting tube (maximum surface roughness Ry = 0.75) having a diameter of 30 mm and a total length of 238.5 mm as a conductive substrate, The film was applied by a dip coating method so as to have a film thickness of 1.5 μm and heat-treated at 130 ° C. for 30 minutes to obtain a sample in which an undercoat layer was formed on a conductive substrate.

Using the spectrocolorimeter (Konica Minolta Co., Ltd., “CM-2500d”, measurement diameter φ: 8, without regular reflection removal), the reflected absorbance at a wavelength of 400 nm or less was measured for the undercoat layer of the obtained sample. The reflection absorbance at a wavelength of 400 nm or less was calculated from the following formula.
(Reflectance at a wavelength of 400 nm or less) = AB
Where A = {(reflected absorbance at a wavelength of 360 nm) + (reflected absorbance at a wavelength of 370 nm) + (reflected absorbance at a wavelength of 380 nm) + (reflected absorbance at a wavelength of 390 nm)} / 4. , B = {(reflected absorbance at a wavelength of 420 nm) + (reflected absorbance at a wavelength of 430 nm) + (reflected absorbance at a wavelength of 440 nm) + (reflected absorbance at a wavelength of 450 nm)} / 4.
The reflection absorbance at a wavelength of 400 nm or less can be obtained only from A, but for the purpose of calculating a more accurate value, in the above formula, in order to exclude the influence of the conductive substrate, from A B is subtracted.
The reflection absorbance was measured 20 times, the reflection absorbance at a wavelength of 400 nm or less was calculated based on the above formula, and the average value and standard deviation (σ) were obtained. Table 1 shows the average value, minimum value, maximum value, standard deviation (σ), and σ / average value.

[Examples 2 to 7]
A sample in which the undercoat layer was formed on the conductive substrate was prepared in the same manner as in Example 1 except that the undercoat layer was formed so that the thickness of the undercoat layer was the value shown in Table 1. The reflection absorbance of the undercoat layer was measured using a colorimeter. The results are shown in Table 1.

[Example 8]
In the same manner as in Example 1, an undercoat layer having a thickness of 1.5 μm was formed on the conductive substrate.
Subsequently, 2 parts by mass of titanyl phthalocyanine as a charge generator, 1 part by mass of polyvinyl butyral resin (manufactured by Denki Kagaku Kogyo Co., Ltd., “Denka Butyral # 6000EP”) as a binder resin, 40 parts by mass of propylene glycol monomethyl ether and tetrahydrofuran (as a solvent) (THF) 40 parts by mass was dispersed by treatment with a bead mill for 2 hours to prepare a charge generation layer coating solution.
The obtained charge generation layer coating solution is filtered through a 3 μm filter, and then applied onto the undercoat layer by a dip coating method and dried at 80 ° C. for 5 minutes to obtain a charge having a thickness of 0.2 μm. A generation layer was formed.
Next, 70 parts by mass of a triphenylamine compound represented by the following formula (1) as a hole transport agent, 10 parts by mass of a hindered phenol compound (dibutylhydroxytoluene) represented by the following formula (2) as an antioxidant, and a binder resin 100 parts by mass of a polycarbonate resin (viscosity average molecular weight: 50000) represented by the following formula (3) was added to 610 parts by mass of tetrahydrofuran as a solvent and dissolved to prepare a coating solution for a charge transport layer.
The obtained charge transport layer coating solution was applied onto the charge generation layer in the same manner as the charge generation layer coating solution, and dried at 120 ° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm. A type electrophotographic photosensitive member was produced.

The surface of the obtained electrophotographic photosensitive member was rubbed with Ben Cotton Clean impregnated with toluene to remove the photosensitive layer (charge generation layer and charge transport layer). This was immersed in THF for 2 minutes, and then washed with THF to remove the photosensitive layer.
The reflection absorbance of the remaining undercoat layer was measured in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Examples 1-8]
Each of the samples obtained in Examples 1 to 8 was used as the object to be inspected, and instead of the spectrocolorimeter, an eddy current film thickness meter (manufactured by Fisher, “Fischer Scope MMS”) was used. The film thickness was measured. Measurement was performed 20 times, and an average value and a standard deviation (σ) were obtained.
Table 2 shows the average value, minimum value, maximum value, standard deviation (σ), and σ / average value.

As is clear from Tables 1 and 2, in the examples in which the reflection absorbance of the undercoat layer was measured using a spectrocolorimeter, the standard deviation and σ / average value were small. In the example, variation in measurement results was small, and measurement errors could be reduced. Usually, a measurement error is likely to occur as the film thickness is reduced. However, in the example, even when the film thickness of the undercoat layer is 1.0 μm or less, the measurement error can be sufficiently reduced.
On the other hand, in the comparative example in which the reflection absorbance of the undercoat layer was measured using an eddy current film thickness meter, the standard deviation and σ / average value were larger than those in the example. In the comparative example, the variation in the measurement result was larger than that in the example, and the measurement had an error. In particular, Comparative Examples 2 to 4 in which the film thickness of the undercoat layer was 1.0 μm or less had a large measurement error.

Claims (7)

In an inspection method for an electrophotographic photoreceptor in which an undercoat layer containing inorganic particles and a photosensitive layer containing a charge generating agent, a charge transport agent, and a binder resin are sequentially laminated on a conductive substrate,
An electrophotographic photosensitive member inspection method comprising: measuring the reflection absorbance of the undercoat layer at a wavelength of 400 nm or less before forming the photosensitive layer.   From an electrophotographic photoreceptor in which an undercoat layer containing inorganic particles and a photosensitive layer containing a charge generator, a charge transport agent, and a binder resin are sequentially laminated on a conductive substrate, the undercoat layer is insoluble. A method for inspecting an electrophotographic photosensitive member, comprising: removing the photosensitive layer with a solvent, and then measuring the reflected absorbance at a wavelength of 400 nm or less for the undercoat layer.   The method for inspecting an electrophotographic photosensitive member according to claim 1, wherein the inorganic particles are titanium oxide.   The method for inspecting an electrophotographic photosensitive member according to claim 3, wherein the titanium oxide is a rutile type.   The method for inspecting an electrophotographic photosensitive member according to claim 3, wherein an average primary particle diameter of the titanium oxide is 100 nm or less. In the method for producing an electrophotographic photosensitive member in which an undercoat layer containing inorganic particles and a photosensitive layer containing a charge generating agent, a charge transporting agent, and a binder resin are sequentially laminated on a conductive substrate,
A method for producing an electrophotographic photoreceptor, comprising: applying a coating solution for forming a photosensitive layer on an undercoat layer whose reflection absorbance at a wavelength of 400 nm or less is measured before forming the photosensitive layer. In the method for producing an electrophotographic photosensitive member in which an undercoat layer containing inorganic particles and a photosensitive layer containing a charge generating agent, a charge transporting agent, and a binder resin are sequentially laminated on a conductive substrate,
The photosensitive layer is formed by removing the photosensitive layer with a solvent insoluble in the undercoat layer from the electrophotographic photosensitive member on which the photosensitive layer is formed, and measuring the reflection absorbance at a wavelength of 400 nm or less for the undercoat layer. A method for producing an electrophotographic photosensitive member, wherein a photosensitive layer is reformed by applying a coating solution.