JP7118762B2 - Electrophotographic photoreceptor inspection method and electrophotographic photoreceptor manufacturing method - Google Patents

Description

The present invention relates to a method for inspecting irregularities in an electrophotographic photoreceptor and a method for producing the same.

As the photosensitive layer of an electrophotographic photoreceptor, a laminated photosensitive layer formed by laminating a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance is mainly used. Laminated photosensitive layers have advantages such as high sensitivity and versatility in material design.

An intermediate layer is generally provided between the charge generating layer and the support. The role of the intermediate layer is to improve the adhesion between the support and the photosensitive layer and to suppress charge injection from the support side to the photosensitive layer side. There is also

However, depending on the state of the defect on the surface of the support, the intermediate layer may not be able to sufficiently conceal the defect, and unevenness may be locally formed on the surface of the intermediate layer. These uneven defects not only cause image defects such as black spots and white spots on the electrophotographic image of the photoreceptor, but also cause dielectric breakdown.

Visual inspection, optical inspection (see Patent Literatures 1 and 2), and electrical inspection (see Patent Literature 3) have been proposed as representative inspections of the uneven shape.

The optical inspection is a method of irradiating a photoreceptor with white light and judging an area with a large change in color density on the surface of the photoreceptor as a defect from an image of the reflected light. If irregularities exist on the surface of the intermediate layer, the pigment aggregates around the irregularities during coating of the charge generation layer. It is possible to optically judge from the color density change around the defect caused by this aggregation. However, with this method, it is not possible to sufficiently distinguish between color density changes due to agglomeration of charge-generating substances that do not affect the image and color density changes due to defects in the unevenness of the intermediate layer that affect the image. I had a problem to remove.

There is also proposed a method of applying a voltage to the surface of a photoreceptor and evaluating the presence or absence of a defect from an excessive current flowing through a defect portion or a current change due to the presence or absence of a defect (see Patent Document 3). This method is effective when the defect on the surface of the support is large to some extent, but it is difficult to obtain a current change with a sufficient SN ratio when the size of the defect is small. I didn't.

JP-A-6-137844 JP-A-11-118449 Japanese Patent Publication No. 2-43134

As described above, various inspection methods have been studied as methods for inspecting unevenness defects in the intermediate layer of an electrophotographic photoreceptor (hereinafter also referred to as "photoreceptor"). However, according to the studies of the present inventors, it cannot be said that the above-described conventional inspection method can sufficiently identify uneven defects in the intermediate layer, and an inspection method for imaging the uneven defects themselves has been desired.

An object of the present invention is to provide a method for inspecting an electrophotographic photoreceptor, which is effective even for a laminated photoreceptor or a photoreceptor in the process of manufacturing, to identify uneven defect shapes of an intermediate layer with sufficiently high accuracy, and to use the inspection method. An object of the present invention is to provide a method for manufacturing an electrophotographic photoreceptor.

The present invention, in one aspect,
A method for inspecting an electrophotographic photoreceptor, comprising inspecting a cylindrical electrophotographic photoreceptor having a support, an intermediate layer, and a photosensitive layer in this order using an inspection mechanism , comprising:
The inspection mechanism
a support means for rotating the electrophotographic photosensitive member , which is an object to be inspected, around its axis;
irradiating means for irradiating the electrophotographic photosensitive member with inspection light having a wavelength of 900 nm or more along the axial direction of the electrophotographic photosensitive member;
an imaging means for receiving reflected light of the inspection light reflected by the intermediate layer of the electrophotographic photosensitive member and acquiring a distribution of the reflected light ;
with
The inspection method is
rotating the electrophotographic photosensitive member about its axis by the supporting means;
a step of causing the inspection light to be incident on the electrophotographic photosensitive member at an angle of θ1° with respect to the normal line of the electrophotographic photosensitive member by the irradiation means ;
a step of receiving the reflected light at an angle of θ2° with respect to the normal line of the electrophotographic photosensitive member by the imaging means, and acquiring the distribution of the reflected light;
a step of discriminating unevenness defects of the intermediate layer from the acquired distribution of the reflected light;
has
The θ1° is 31° or more and 63° or less,
The θ2° is θ1+1° or more and θ1+2° or less ,
An object of the present invention is to provide a method for inspecting an electrophotographic photoreceptor characterized by:

According to the present invention, an electrophotographic photoreceptor inspection method capable of accurately determining the uneven defect shape of an intermediate layer in a laminated photoreceptor and accurately determining uneven defects even in a non-laminated photoreceptor, and a method for manufacturing an electrophotographic photoreceptor using the inspection method.

1 is a diagram showing a conceptual side view of an inspection apparatus for an electrophotographic photosensitive member; FIG. FIG. 2 is a diagram showing an example of a cross section of an electrophotographic photosensitive member to be inspected;

The present invention is an electrophotographic photoreceptor inspection method for inspecting a cylindrical electrophotographic photoreceptor having a support, an intermediate layer and a photosensitive layer in this order using an inspection mechanism , comprising:
The inspection mechanism
a support means for rotating the electrophotographic photosensitive member , which is an object to be inspected, around its axis;
irradiating means for irradiating the electrophotographic photosensitive member with inspection light having a wavelength of 900 nm or more along the axial direction of the electrophotographic photosensitive member;
an imaging means for receiving reflected light of the inspection light reflected by the intermediate layer of the electrophotographic photosensitive member and acquiring a distribution of the reflected light ;
with
The inspection method is
rotating the electrophotographic photosensitive member about its axis by the supporting means;
a step of causing the inspection light to be incident on the electrophotographic photosensitive member at an angle of θ1° with respect to the normal line of the electrophotographic photosensitive member by the irradiation means ;
a step of receiving the reflected light at an angle of θ2° with respect to the normal line of the electrophotographic photosensitive member by the imaging means, and acquiring the distribution of the reflected light;
a step of discriminating unevenness defects of the intermediate layer from the acquired distribution of the reflected light;
has
The θ1° is 31° or more and 63° or less,
The θ2° is θ1+1° or more and θ1+2° or less ,
A method for inspecting an electrophotographic photosensitive member characterized by:

Furthermore, the present invention relates to the inspection method described above , wherein the regular reflectance of the intermediate layer at the wavelength of the inspection light is 80% or more.

Furthermore, the present invention relates to the inspection method described above, wherein the photosensitive layer has a charge generation layer that does not have an absorption band in the wavelength of the inspection light.

Furthermore, in the present invention, the inspection mechanism further comprises image processing means for determining the uneven defect ,
The image processing means is
an extracting means for extracting a defect candidate area in the imaging range of the imaging means ;
a means having a function of extracting a projected profile of the defect candidate region, obtaining a symmetrical correlation coefficient of the accumulated profile, and discriminating the uneven defect from the shape of the intermediate layer ;
comprising
The inspection method described above.

Further, the present invention provides a method for manufacturing an electrophotographic photoreceptor, comprising a support, an intermediate layer and a photosensitive layer in this order, wherein the electrophotographic photoreceptor is manufactured by the inspection method described above. The present invention relates to a method for manufacturing an electrophotographic photoreceptor, comprising a step of inspecting the photoreceptor.

(Inspection methods)
The inspection method of the present invention is
By using the inspection light in the wavelength range that passes through the charge generation layer and by setting the light receiving angle to a region that picks up diffused light rather than specularly reflected light, it is possible to accurately detect intermediate light without picking up density unevenness in the charge generation layer. It is possible to obtain the unevenness distribution of the layer.

The incident light must be incident at an angle of θ1° of 31° or more and 63° or less with respect to the normal line of the electrophotographic photosensitive member, which is the object to be inspected. If .theta.1.degree . Further, when θ1° is an angle larger than 63 °, the contrast of the shadow of the uneven shape of the defect is low, and the uneven defect cannot be discriminated. In addition, the reflected light must have a light-receiving angle θ2 ° with respect to the normal line of θ1+1 ° or more and θ1+2 ° or less . By setting this angle, it is possible to image the unevenness defect of the intermediate layer more clearly. At an angle that is more diffuse than this angle, the amount of received light is small, and it is not possible to determine uneven defects with a sufficient S/N ratio.

Moreover, it is desirable that the intermediate layer has a regular reflectance of 70% or more, more preferably 80% or more, at the wavelength of the inspection light. Even if the specular reflectance is 70% or less, if the incident and light receiving angles are set within the above-mentioned angle range, uneven defects in the intermediate layer can be identified. may be lower.

In the case of a laminated photoreceptor, it is desirable that the absorption region of the charge generation layer and the wavelength region of the inspection light do not overlap. Even in the case of overlap, sufficient measurement is possible as long as the amount of light that passes through the charge generation layer is large. can be done.

When irradiating the laminated photoreceptor, the irradiation wavelength is desirably 900 nm or more. This wavelength range is useful in that it does not cause adverse effects such as photo memory on the photoreceptor, and as mentioned above, it is a wavelength range outside the absorption band of the charge generation layer, especially the absorption band of phthalocyanine pigments used as general-purpose charge generation materials. is.

As the irradiation light source, an LED, a xenon lamp, a mercury/xenon lamp, or the like is used. If the radiance in the above wavelength range is the strongest, light in other wavelength ranges may be present. is preferably selected.

A reflected light imaging device is a light receiving means composed of a photoelectric conversion element, and examples thereof include a line sensor type CCD camera and a photomultiplier tube (photomultiplier). If necessary, it is sufficient to include the above wavelength range, and other wavelength ranges may be included.

When an uneven defect is observed at the above incident/light-receiving angles, on the other hand, a convex defect provides a reflected light distribution in which the brightness of the peak on the incident light side is high and the brightness of the peak on the light-receiving side is low. On the other hand, if the defect is a concave defect, the brightness of the valley on the incident light side is low, and the brightness of the valley on the light receiving side is high. In this way, the reflected light distribution of the uneven defect imaged at a certain angle is a distribution in which the high luminance area and the low luminance area are clearly separated. In the case where the irregularity defect is of a regular cone type, the distribution of high and low luminance areas is more symmetrical. Further, among the irregularities in the intermediate layer, when the defects on the surface of the support protrude into the intermediate layer, regular conical irregularities are often obtained. The characteristic shape of the luminance distribution of these irregularities can be identified by the human eye, but based on the stability and quantification of inspection, a method of mechanically distinguishing by image processing without relying on the human eye is proposed. An example is given below.

First, a smoothing process is performed for the purpose of removing background noise and global shadows in the imaging plane caused by eccentricity of rotation of the photoreceptor. As a specific example, the difference between an image smoothed using a small smoothing filter for the purpose of removing background noise and an image smoothed using a large smoothing filter for the purpose of leaving only global gradation information in the plane is taken. By obtaining an image from which the global gradation is removed from the small smooth image, an image is obtained. A smoothing filter, such as a moving average filter, median filter, or Gaussian filter, should be selected as appropriate while checking the image noise removal state after processing.

Next, an example of a method of obtaining a circumscribing rectangle of a defect candidate to be determined will be described. First, binarization processing is performed on an image that has undergone smoothing processing, and pixels with brightness higher than the white threshold and pixels with brightness lower than the black threshold are extracted. As a result, it is possible to extract a defect with symmetrical luminance levels, such as an uneven defect. Next, dilation processing is performed to replace the maximum value in the kernel with the value of the pixel of interest, and the uneven defect pixels are grouped together. After reduction processing is performed for the purpose of removing minute points in the plane, expansion processing is performed again to obtain a circumscribing rectangle of the obtained mass of white pixels.

After obtaining the projection profile in the generatrix direction of the photoreceptor for the defect candidate area thus extracted, the correlation coefficient of the symmetry of the accumulated profile is obtained. A defect such as a concave-convex defect in which bright and dark pixel regions are symmetrically divided has high symmetry. On the other hand, other defects such as aggregation of charge-generating pigments and shadow patterns due to dirt and dust adhering to the surface of the intermediate layer are asymmetrical, and can be distinguished from uneven defects by a series of treatments.

Next, the inspection process of the present invention will be described in detail.
First, FIG. 1 shows an example of a schematic diagram of a photoreceptor 1 to be inspected in the inspection process of the present invention, and a light source 2 and light receiving means 3 used for the inspection.
While rotating the photoreceptor 1 in the direction of the arrow, the light source 2 irradiates the photoreceptor 1 with an incident angle of θ1 with respect to the normal line of the photoreceptor 1 . The light to be irradiated is light with a wavelength of 900 nm or more. A light receiving means 3 is provided at an angle .theta.2 with respect to the normal line of the photosensitive member 1, and a reflected light distribution is obtained by an imaging means (not shown).

FIG. 2 shows a photoreceptor 1 as an example of an inspection object to be inspected in the present invention. 24 and a surface layer 25 are laminated in this order. If there is a convex defect 26 in the intermediate layer, density unevenness will appear in the charge generation layer 24 thereabove.

[Support]
As the support, one having conductivity (conductive support) is preferable. For example, supports made of metals or alloys such as aluminum, iron, nickel, copper, and gold can be used. Supports obtained by forming a thin film of a metal such as aluminum, chromium, silver, or gold on an insulating support such as polyester resin, polycarbonate resin, polyimide resin, or glass can be used.

[Intermediate layer]
An intermediate layer is provided on the support.
The intermediate layer contains metal oxide particles for the purpose of imparting electrical conductivity. The intermediate layer is formed by coating an intermediate layer coating liquid containing metal oxide particles on a support using a solvent, a binder resin, etc. to form a coating film, and drying and/or curing the resulting coating film. can be formed by letting

Dispersion methods include, for example, methods using a paint shaker, sand mill, ball mill, and liquid collision type high-speed disperser.

A phenol resin, a urethane resin, or an amino resin may be used as the binder resin. Solvents used in the intermediate layer coating liquid include, for example, alcohols such as methanol, ethanol and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; tetrahydrofuran, dioxane, ethylene glycol monomethyl ether and propylene glycol monomethyl ether. ethers, esters such as methyl acetate and ethyl acetate, and aromatic hydrocarbons such as toluene and xylene.

In addition, in order to suppress the occurrence of interference fringes in an output image due to interference of light reflected on the surface of the intermediate layer, the intermediate layer coating liquid contains a surface roughening agent for roughening the surface of the intermediate layer. An imparting material may be contained. Resin particles having an average particle size of 1 μm or more and 5 μm or less are preferable as the surface roughening agent. Examples of resin particles include particles of curable resins such as curable rubbers, polyurethanes, epoxy resins, alkyd resins, phenol resins, polyesters, silicone resins, and acrylic-melamine resins. Among these, particles of silicone resin that are difficult to agglomerate are preferable. Further, the intermediate layer coating solution may contain a leveling agent for enhancing the surface properties of the intermediate layer. Further, the intermediate layer coating liquid may contain pigment particles in order to further improve the concealability of the intermediate layer.

The mass ratio of the metal oxide particles to the binder resin is preferably 5/1 to 0.5/1, more preferably 3/1 to 1/1.

Also, the film thickness of the intermediate layer is suitably 2 to 40 μm, preferably 10 to 30 μm.

The ten-point average roughness Rzjis at the reference length of 0.8 mm of the intermediate layer is preferably 0.5 μm or more and 2.5 μm or less from the viewpoint of leak resistance.

[Second intermediate layer]
A second intermediate layer may be further provided on the intermediate layer. Conversely, after removing the intermediate layer, only the second intermediate layer may be applied.

The second intermediate layer is made of water-soluble resins such as polyvinyl alcohol, polyvinyl methyl ether, polyacrylic acids, methyl cellulose, ethyl cellulose, polyglutamic acid, casein, starch, polyamide, polyimide, polyamideimide, polyamic acid, melamine resin, epoxy resin, Consists of polyurethane, polyglutamic acid ester, and the like.

The second intermediate layer may also contain an organic electron-transporting substance, and examples of the organic electron-transporting substance include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, and the like. Since the organic electron transporting substance is preferably incorporated into the polymer in order to suppress elution into the charge generation layer, it is preferably an electron transporting substance having a polymerizable functional group. Polymerizable functional groups include hydroxy groups, thiol groups, amino groups, carboxyl groups, or methoxy groups. Specific examples of the electron-transporting substance are shown below as compounds represented by any one of the following formulas (A1) to (A11).

In formulas (A1) to (A11), R ¹¹ to R ¹⁶ , R ²¹ to R ³⁰ , R ³¹ to R ³⁸ , R ⁴¹ to R ⁴⁸ , R ⁵¹ to R ⁶⁰ , R ⁶¹ to R ⁶⁶ , R ⁷¹ to R ⁷⁸ , R ⁸¹ to R ⁹⁰ , R ⁹¹ to R ⁹⁸ , R ¹⁰¹ to R ¹¹⁰ and R ¹¹¹ to R ¹²⁰ are each independently a monovalent group represented by the following formula (A), a hydrogen atom, cyano group, nitro group, halogen atom, alkoxycarbonyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, or substituted or unsubstituted heterocyclic ring. One _CH2 in the main chain of the alkyl group may be replaced with O, S, NH or ^NR121 ( ^R121 is an alkyl group). at least one of R ¹¹ to R ¹⁶ , at least one of R ²¹ to R ³⁰ , at least one of R ³¹ to R ³⁸ , at least one of R ⁴¹ to R ⁴⁸ , at least one of R ⁵¹ to R ⁶⁰ , at least one of R ⁶¹ to R ⁶⁶ , at least one of R ⁷¹ to R ⁷⁸ , at least one of R ⁸¹ to R ⁹⁰ , at least one of R ⁹¹ to R ⁹⁸ , at least one of R ¹⁰¹ to R ¹¹⁰ , At least one of R ¹¹¹ to R ¹²⁰ has a monovalent group represented by formula (A).

The substituents of the substituted alkyl group are alkyl groups, aryl groups, halogen atoms and alkoxycarbonyl groups. The substituent of the substituted aryl group and the substituent of the substituted heterocyclic group are a halogen atom, a nitro group, a cyano group, an alkyl group, a halogen-substituted alkyl group and an alkoxy group. Z ²¹ , Z ³¹ , Z ⁴¹ and Z ⁵¹ each independently represent a carbon atom, a nitrogen atom or an oxygen atom. R ²⁹ and R ³⁰ are absent when Z ²¹ is an oxygen atom, and R ³⁰ is absent when Z ²¹ is a nitrogen atom. R ³⁷ and R ³⁸ are absent when Z ³¹ is an oxygen atom, and R ³⁸ is absent when Z ³¹ is a nitrogen atom. R ⁴⁷ and R ⁴⁸ are absent when Z ⁴¹ is an oxygen atom, and R ⁴⁸ is absent when Z ⁴¹ is a nitrogen atom. R ⁵⁹ and R ⁶⁰ are absent when Z ⁵¹ is an oxygen atom, and R ⁶⁰ is absent when Z ⁵¹ is a nitrogen atom.

式（Ａ）中、α、β、及びγの少なくとも１つは置換基を有する基であり、置換基は、ヒドロキシ基、チオール基、アミノ基、カルボキシル基及びメトキシ基からなる群より選択される少なくとも１種の基である。ｌ及びｍは、それぞれ独立に、０又は１であり、ｌとｍの和は、０以上２以下である。

In formula (A), at least one of α, β, and γ is a group having a substituent, and the substituent is selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group, and a methoxy group. at least one group. l and m are each independently 0 or 1, and the sum of l and m is 0 or more and 2 or less.

α is an alkylene group having a main chain of 1 to 6 atoms, an alkylene group having a main chain of 1 to 6 atoms substituted with an alkyl group having 1 to 6 carbon atoms, or an alkylene group having a main chain of 1 to 6 atoms substituted with a benzyl group. an alkylene group having 1 to 6 atoms, an alkylene group having a main chain having 1 to 6 atoms substituted with an alkoxycarbonyl group, or an alkylene group having a main chain having 1 to 6 atoms substituted with a phenyl group; . These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group and a methoxy group as a substituent. One CH ₂ in the main chain of the alkylene group may be replaced with O, S, NR ¹²² (wherein R ¹²² represents a hydrogen atom or an alkyl group).

β represents a phenylene group, an alkyl-substituted phenylene group having 1 to 6 carbon atoms, a nitro-substituted phenylene group, a halogen-substituted phenylene group, or an alkoxy-substituted phenylene group. These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group and a methoxy group as a substituent.

γ represents a hydrogen atom, an alkyl group having a main chain of 1 to 6 atoms, or an alkyl group having a main chain of 1 to 6 atoms substituted with an alkyl group of 1 to 6 carbon atoms. These groups may have at least one group selected from the group consisting of a hydroxy group, a thiol group, an amino group, a carboxyl group and a methoxy group as a substituent. One _CH2 in the main chain of the alkyl group may be replaced with O or S or ^NR123 (wherein ^R123 represents a hydrogen atom or an alkyl group).

または式（Ａ１０２）で示される構造式などが挙げられる。

Specific examples of the group represented by formula (A) include the structural formula represented by formula (A101),

Alternatively, a structural formula represented by Formula (A102), or the like can be mentioned.

In the present invention, more preferably, the second intermediate layer is made of a polymer composition containing an organic electron-transporting substance. This suppresses irregular reflection and increases the intensity of reflected light, thereby improving the accuracy of inspection. .
Moreover, the second intermediate layer may contain a metal oxide, if necessary.

[Charge generation layer]
A charge generation layer is formed on the intermediate layer (or on the second intermediate layer when the second intermediate layer is present).

As the charge-generating substance used in the present invention, a substance having a property of absorbing the wavelength of light used in the inspection process is used. Specifically, azo pigments, phthalocyanine pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, squarylium pigments, thiapyrylium salts, triphenylmethane pigments, quinacridone pigments, azulenium salt pigments, cyanine dyes, anthanthrone pigments, and pyranthrone pigments. , xanthene dyes, quinone imine dyes, styryl dyes, and the like. Only one kind of these charge generation substances may be used, or two or more kinds thereof may be used. Among these charge-generating substances, phthalocyanine pigments and azo pigments are preferred from the viewpoint of sensitivity, and phthalocyanine pigments are more preferred.

Among the phthalocyanine pigments, oxytitanium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine exhibit excellent charge generation efficiency. Furthermore, among hydroxygallium phthalocyanines, from the viewpoint of sensitivity, crystalline hydroxy gallium phthalocyanine having peaks at Bragg angles 2θ of 7.4° ± 0.3° and 28.2° ± 0.3° in CuKα characteristic X-ray diffraction. Gallium phthalocyanine crystals are more preferred.

Binder resins used in the charge generation layer include acrylic resins, allyl resins, alkyd resins, epoxy resins, diallyl phthalate resins, styrene-butadiene copolymers, butyral resins, benzal resins, polyacrylate resins, polyacetal resins, polyamideimide resins, Polyamide resin, polyallyl ether resin, polyarylate resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl acetal resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin, chloride Examples include vinyl-vinyl acetate copolymers, vinyl acetate resins, and vinyl chloride resins. Among these, butyral resins are particularly preferred. These may be used singly, as a mixture, or as a copolymer, or two or more.

The charge-generating layer can be formed by applying a charge-generating layer coating liquid obtained by dispersing a charge-generating substance together with a binder resin and a solvent, followed by drying. Also, the charge generation layer may be a deposited film of a charge generation substance.

Dispersion methods include methods using homogenizers, ultrasonic dispersers, ball mills, sand mills, roll mills, vibration mills, attritors, and liquid collision high-speed dispersers.
As for the ratio of the charge-generating substance and the binder resin, it is more preferable that the charge-generating substance is 0.3 parts by mass or more and 10 parts by mass or less per 1 part by mass of the binder resin.

Solvents used in the charge generation layer coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, aliphatic halogenated hydrocarbon solvents, and aromatic compounds. The thickness of the charge generating layer is preferably 0.01 μm or more and 5 μm or less, more preferably 0.1 μm or more and 2 μm or less. In addition, various sensitizers, antioxidants, ultraviolet absorbers and plasticizers can be added to the charge generating layer as required.

[Surface layer]
A surface layer is formed on the charge generation layer. The surface layer contains charge transport material and resin.

Charge-transporting substances used in the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, and butadiene compounds. These charge transport substances may be used alone or in combination of two or more. Among these, triarylamine compounds are preferred from the viewpoint of charge mobility.

In the case of a laminated photosensitive layer, binder resins used in the surface layer include acrylic resins, acrylonitrile resins, allyl resins, alkyd resins, epoxy resins, silicone resins, phenol resins, phenoxy resins, polyacrylamide resins, and polyamideimide resins. , polyamide resins, polyallyl ether resins, polyarylate resins, polyimide resins, polyurethane resins, polyester resins, polyethylene resins, polycarbonate resins, polysulfone resins, polyphenylene oxide resins, polybutadiene resins, polypropylene resins, methacrylic resins, and the like. Among these, polyarylate resins and polycarbonate resins are preferred. These may be used singly, as a mixture, or as a copolymer, or two or more.

The surface layer can be formed by applying a surface layer coating liquid obtained by dissolving a charge transporting substance and a binder resin in a solvent and drying the liquid. The ratio of the charge transport material and the binder resin in the surface layer is preferably 0.3 parts by mass or more and 10 parts by mass or less for the charge transport material per 1 part by mass of the binder resin. From the viewpoint of suppressing cracks in the surface layer, the drying temperature is preferably 60° C. or higher and 150° C. or lower, more preferably 80° C. or higher and 120° C. or lower. Moreover, the drying time is preferably 10 minutes or more and 60 minutes or less.

Solvents used in the surface layer coating solution include alcohol solvents such as propanol and butanol (especially alcohols having 3 or more carbon atoms), aromatic hydrocarbon solvents such as anisole, toluene, xylene, and chlorobenzene, methylcyclohexane, and ethylcyclohexane.

In the present invention, when the object to be inspected is an electrophotographic photoreceptor, it is desirable to intensify the light entering the second intermediate layer. This is preferable because the difference in strength increases.

In the present invention, even if the thickness unevenness and thickness of the surface layer are different, the thickness unevenness and film residue of the second intermediate layer can be accurately determined.

When the electrophotographic photosensitive member has a single surface layer, the thickness of the surface layer is preferably 5 μm or more and 40 μm or less, and more preferably 8 μm or more and 30 μm or less from the viewpoint of transparency.

When the surface layer has a laminated structure, the thickness of the layer on the support side is preferably 5 μm or more and 20 μm or less, and the thickness of the layer on the surface side is preferably 1 μm or more and 8 μm or less.
The transmittance of all layers in the laminated structure is preferably 97% or more.

Moreover, an antioxidant, an ultraviolet absorber, a plasticizer, etc. can also be added to the surface layer as needed.

The surface layer of the electrophotographic photosensitive member may contain silicone oil, wax, fluorine atom-containing resin particles such as polytetrafluoroethylene particles, silica particles, alumina particles, and lubricants such as boron nitride.

When applying the coating solution for each layer, for example, a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like can be used. can be done.

The present invention will be described in more detail below with specific examples. However, the present invention is not limited to these. In addition, "part" in an Example means "mass part."

(Photoreceptor Production Example 1)
An aluminum cylinder (JIS-A3003, aluminum alloy) having a length of 260.5 mm and a diameter of 30 mm was used as a support (conductive support).

Intermediate layer: 214 parts of titanium oxide (TiO ₂ ) particles (number average primary particle diameter: 200 nm) coated with oxygen-deficient tin oxide (SnO ₂ ) as metal oxide particles, phenolic resin (product Name: Pryofen J-325.) 132 parts, and
40 parts of methanol, 58 parts of 1-methoxy-2-propanol,
Placed in a sand mill using 450 parts of glass beads having a diameter of 0.8 mm, and subjected to dispersion treatment under the conditions of rotation speed: 2000 rpm, dispersion treatment time: 4.5 hours, cooling water set temperature: 18 ° C., to obtain a dispersion liquid. rice field. The glass beads were removed from this dispersion with a mesh (opening: 150 μm). Silicon oil (SH28PA, manufactured by Dow Corning Toray Co., Ltd.) as a leveling agent was added so as to be 0.01% by mass with respect to the total mass of the metal oxide particles and the binder resin in the dispersion after removing the glass beads. and 15% by mass of silicone resin particles (Tospearl 120, manufactured by Momentive Performance Materials Japan LLC). By stirring this dispersion, an intermediate layer coating liquid was prepared. This intermediate layer coating liquid was applied onto the support by dip coating, and the resulting coating film was dried and thermally cured at 160° C. for 60 minutes to form a first intermediate layer having a thickness of 30.2 μm. Also, the reflectance in the range of 1 to 2° measured using a goniometer was 95%.

Next, a second intermediate layer was formed on the first intermediate layer by the following method.
4.5 parts of N-methoxymethylated nylon (trade name: Toresin EF-30T, manufactured by Nagase ChemteX Co., Ltd. (former Teikoku Kagaku Sangyo Co., Ltd.)) and copolymerized nylon resin (trade name: Amilan CM8000, Toray Co., Ltd.) was dissolved in a mixed solvent of 65 parts of methanol/30 parts of n-butanol to prepare a second intermediate layer coating solution. This second intermediate layer coating solution was dip-coated on the first intermediate layer and dried at 70° C. for 6 minutes to form a second intermediate layer having a thickness of 0.4 μm.

Charge generation layer:
Hydroxygallium phthalocyanine crystal (charge-generating substance, CuKα Bragg angle (2θ ± 0.2°) of 7.5°, 9.9°, 12.5°, 16.3°, 18.6° in characteristic X-ray diffraction , with peaks at 25.1° and 28.3°.) 10 parts,
5 parts of polyacetal resin (trade name: S-Lec BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone were placed in a sand mill using glass beads with a diameter of 1 mm and dispersed for 1.5 hours. Next, 250 parts of ethyl acetate was added to this to prepare a charge generation layer coating solution. The charge generation layer coating solution was dip-coated on the second intermediate layer and the exposed surface of the first intermediate layer, and the resulting coating film was dried at 100° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm. formed a layer.

Surface layer:
7 parts of an amine compound represented by the following formula (4) as a charge transport material;
10 parts of a polyester resin having a structural unit represented by formulas (5) and (6) and having a molar ratio of formulas (5) and (6) of 5/5 and a weight average molecular weight of 120,000,
Dissolved in a mixed solvent of 50 parts of dimethoxymethane and 50 parts of O-xylene, and further silica fine particles (Shin-Etsu Chemical Co., Ltd. KMPX-100: average primary particle size 0.1 μm) with respect to the solid content, 2 mass% By adding and stirring, a surface layer coating liquid was prepared. This surface layer coating liquid was applied onto the charge generation layer by dip coating, and the resulting coating film was dried at 120° C. for 20 minutes to form a surface layer as a charge transport layer having a thickness of 20 μm.

(Photoreceptor Production Example 2)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that the first intermediate layer was changed as follows.
207 parts of titanium oxide particles (TiO ₂ ) coated with phosphorus (P)-doped tin oxide (SnO ₂ ) as conductive particles; 144 parts of J-325) and 98 parts of 1-methoxy-2-propanol as a solvent were placed in a sand mill using 450 parts of glass beads with a diameter of 0.8 mm, and the number of revolutions was 2000 rpm, and the dispersion treatment time was 4. Dispersion treatment was carried out for 5 hours under the condition that the set temperature of the cooling water was 18°C, and a dispersion liquid was obtained.
The glass beads were removed from this dispersion with a mesh (opening: 150 μm). Silicone resin particles (trade name: Tospearl 120) were added to the dispersion in an amount of 15% by mass with respect to the total mass of the metal oxide particles and the binder material in the dispersion after removing the glass beads. Further, silicone oil (trade name: SH28PA) is added to the dispersion and stirred so that the total mass of the metal oxide particles and the binder material in the dispersion is 0.01% by mass. An intermediate layer coating solution was prepared. This intermediate layer coating liquid was applied onto the support by dip coating, and the resulting coating film was dried and thermally cured at 150° C. for 30 minutes to form an intermediate layer having a thickness of 30 μm. Also, the reflectance in the range of 1 to 2° measured using a goniometer was 88%.

(Photoreceptor Production Example 3)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that the first intermediate layer was changed as follows.
Barium sulfate particles coated with tin oxide (trade name: Pastran PC1, manufactured by Mitsui Kinzoku Mining Co., Ltd.) 60 parts, titanium oxide particles (trade name: TITANIX JR, manufactured by Tayca Co., Ltd.) 15 parts, resol type phenolic resin ( Product name: Phenolite J-325, manufactured by Dainippon Ink and Chemicals Co., Ltd., solid content 70% by mass) 43 parts, silicone oil (product name: SH28PA, manufactured by Toray Silicone Co., Ltd.) 0.015 parts, silicone resin (trade name: Tospearl 120, manufactured by Toshiba Silicone Co., Ltd.) 3.6 parts, 2-methoxy-1-propanol 50 parts, methanol 50 parts dispersion treatment for 20 hours in a ball mill to obtain an intermediate layer A coating liquid was prepared. This intermediate layer coating solution was dip-coated on an aluminum cylinder (diameter 24 mm, conductive support) as a support, and the resulting coating film was dried at 140°C for 30 minutes to give a film thickness of 15 µm. An intermediate layer was formed. Also, the reflectance in the range of 1 to 2° measured using a goniometer was 90%.

また、ゴニオメータを用い測定した１～２°範囲の反射率は、８５％であった。 (Photoreceptor Production Example 4)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that the first intermediate layer was changed as follows and the second intermediate layer was not applied.
100 parts of zinc oxide particles (average primary particle size: 50 nm, specific surface area: 19 m ² /g, powder resistance: 1.0 × 10 ⁷ Ω·cm, manufactured by Tayca Corporation) was mixed with 500 parts of toluene while stirring. did. To this, 0.75 part of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a surface treatment agent and mixed with stirring for 2 hours. . Thereafter, toluene was distilled off under reduced pressure, and the residue was dried at 120°C for 3 hours to obtain surface-treated zinc oxide particles.
100 parts of titanium oxide particles (trade name: JR-405, average primary particle size: 210 nm, manufactured by Tayca Co., Ltd.) were mixed with 500 parts of toluene while stirring. To this, 0.75 part of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a surface treatment agent and mixed with stirring for 2 hours. . Thereafter, toluene was distilled off under reduced pressure, and the residue was dried at 120°C for 3 hours to obtain surface-treated titanium oxide particles.
100 parts of the surface-treated zinc oxide particles, 12 parts of the surface-treated titanium oxide, a blocked isocyanate compound represented by formula (8) (trade name: Sumidur 3175, solid content: 75% by mass, Sumitomo Bayer Urethane Co., Ltd.) 30 parts, polyvinyl butyral resin (trade name: S-Lec BM-1, manufactured by Sekisui Chemical Co., Ltd.) 15 parts, 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 parts were added to a mixed solvent of 70 parts of methyl ethyl ketone and 70 parts of cyclohexanone to prepare a dispersion.
This dispersion liquid was subjected to dispersion treatment using glass beads having an average particle size of 1.0 mm in a vertical sand mill under an atmosphere of 23° C. and a rotation speed of 1,500 rpm for 3 hours. After dispersion treatment, 7 parts of crosslinked polymethyl methacrylate particles (trade name: SSX-103, average particle size: 3 μm, manufactured by Sekisui Chemical Co., Ltd.) and silicone oil (trade name: SH28PA, 0.01 part of Dow Corning Toray Co., Ltd.) was added and stirred to prepare an intermediate layer coating solution. This intermediate layer coating liquid was applied onto a support by dip coating to form a coating film, and the coating film was dried at 170° C. for 20 minutes to form an intermediate layer having a thickness of 30 μm.

Also, the reflectance in the range of 1 to 2° measured using a goniometer was 85%.

(Photoreceptor Production Example 5)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that the charge generation layer was changed as follows.
30 parts of a chlorogallium phthalocyanine pigment having peaks at 7.4°, 16.6°, 25.5° and 28.4° with a Bragg angle of 2θ ± 0.2° in an X-ray diffraction spectrum using CuKα rays; 10 parts of polyvinyl butyral (trade name: S-lec BX-1, manufactured by Sekisui Chemical Co., Ltd.), 253 parts of cyclohexanone, and 354 parts of glass beads with a diameter of 0.9 mm are heated at a cooling water temperature of 18 ° C. for 4 hours, and a sand mill (K-800, Igarashi Dispersion treatment was carried out using a machine manufacturing machine (now Imex), disk diameter 70 mm, number of disks: 5). At this time, the disk was rotated 1,800 times per minute. A charge generating layer coating solution was prepared by adding 592 parts of cyclohexanone and 845 parts of ethyl acetate to this dispersion. This charge generating layer coating solution is dip-coated on the above-mentioned second intermediate layer and the exposed first intermediate layer to form a coating film, and the coating film is dried by heating at 100° C. for 10 minutes to obtain a film thickness. A charge generating layer of 150 nm was formed.

(Photoreceptor Preparation Example 6)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that the charge generation layer was changed as follows.

In the X-ray diffraction spectrum using CuKα rays, 12 parts of titanyl phthalocyanine pigment having a peak at 27.2° ± 0.2° of Bragg angle 2θ, polyvinyl butyral (trade name: S-Lec BX-1, manufactured by Sekisui Chemical Co., Ltd.) 10 parts, 139 parts of cyclohexanone, and 354 parts of glass beads with a diameter of 0.9 mm were mixed with cooling water at a temperature of 18° C. for 4 hours in a sand mill (K-800, manufactured by Igarashi Kikai Seisakusho (currently Imex), disk diameter: 70 mm, number of disks: 5). ) was used for dispersion processing. At this time, the disk was rotated 1,800 times per minute. A charge generation layer coating liquid was prepared by adding 326 parts of cyclohexanone and 465 parts of ethyl acetate to this dispersion liquid. This charge generating layer coating solution is dip-coated on the above-mentioned second intermediate layer and the exposed first intermediate layer to form a coating film, and the coating film is dried by heating at 100° C. for 10 minutes to obtain a film thickness. A charge generating layer of 150 nm was formed.

Electrophotographic photoreceptors having three types of defects per photoreceptor were produced by the following method for the photoreceptors 1 to 6 produced by the above method.

(Defect production example 1-A)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that the intermediate layer coating mass was adhered to the surface before the intermediate layer was dried. After drying the intermediate layer, the height of the convexity on the surface was observed with a laser microscope VK-9500 (manufactured by KEYENCE CORPORATION).

(Defect Production Example 1-B)
A photoreceptor was produced in the same manner as in Photoreceptor Production Example 1, except that after the intermediate layer was dried, the tip of the center punch (Φ1) was pressed against the intermediate layer at 10 N to form recesses. After processing the intermediate layer, the depth of the recesses on the surface was observed with a laser microscope to be 7.4 μm, and the major axis length was 102.0 μm.

(Defect production example 1-C)
A photoreceptor was prepared in the same manner as in Photoreceptor Preparation Example 1, except that the coating mass of the charge generation layer was adhered to the surface before the charge generation layer was dried.

(Defect production example 2-A) ~ (2-C)
(Defect Preparation Example 1-A) to (1-C) were performed in the same manner as (Defect Preparation Example 1-A) to (1-C) except that the photoreceptor prepared in Photoreceptor Preparation Example 2 was used. A photoreceptor was produced. Table 1 shows the intermediate layer protrusion height and the major axis length of the defect.

(Defect Production Example 3-A) ~ (3-C)
(Defect Preparation Example 1-A) to (1-C) were performed in the same manner as (Defect Preparation Example 1-A) to (1-C) except that the photoreceptor prepared in Photoreceptor Preparation Example 3 was used. A photoreceptor was produced. Table 1 shows the intermediate layer protrusion height and the major axis length of the defect.

(Defect Production Example 4-A) ~ (4-C)
(Defect Preparation Example 1-A) to (1-C) were performed in the same manner as (Defect Preparation Example 1-A) to (1-C) except that the photoreceptor prepared in Photoreceptor Preparation Example 4 was used. A photoreceptor was produced. Table 1 shows the intermediate layer protrusion height and the major axis length of the defect.

(Defect Production Example 5-A) ~ (5-C)
(Defect Preparation Example 1-A) to (1-C) were performed in the same manner as (Defect Preparation Example 1-A) to (1-C) except that the photoreceptor prepared in Photoreceptor Preparation Example 5 was used. A photoreceptor was produced. Table 1 shows the intermediate layer protrusion height and the major axis length of the defect.

(Defect Production Example 6-A) ~ (6-C)
(Defect Preparation Example 1-A) to (1-C) were performed in the same manner as in (Defect Preparation Example 1-A) to (1-C) except that the photoreceptor prepared in Photoreceptor Preparation Example 6 was used. A photoreceptor was produced. Table 1 shows the intermediate layer protrusion height and the major axis length of the defect.

As described above, three types of defects, convex, concave, and pigment aggregation, were produced for each photoreceptor structure. Table 1 also shows the sizes of the external appearance measured by human visual inspection. As far as the appearance was visually observed, the shapes of various defects A to C could not be determined.

(Example 1)
For Defect Production Examples 1-A to 1-C, an LED with a wavelength of 940 nm was used as inspection light, and a line sensor with 2048 pixels (Takenaka System Equipment: TL-2048UCL) was used as imaging means. The inspection light is placed at an angle of 45° with respect to the normal line of the photoreceptor, and the line camera is arranged at an angle of 46° with respect to the normal line. image was obtained.
The obtained observed image was subjected to image processing according to the following procedure, and the correlation coefficient of the defect corresponding portion was obtained. Table 2 shows the results.

<Image processing procedure>
By obtaining the difference between the image smoothed using a 3×3 small smoothing filter and the image smoothed using a 31×31 large smoothing filter, an image with global gradation removed from the small smoothed image was obtained. . Next, binarization processing was performed by setting the white side threshold value to 138 and the black side threshold value to 118. FIG. Next, dilation processing is performed with a kernel size of 3×3, followed by reduction processing of 5×5 and dilation processing of 5×5 again. A projection profile within the candidate region is obtained. For this projection profile, the correlation coefficient of the symmetry of the accumulated profile was determined, and the values shown in Table 2 were obtained.
When the correlation coefficient was 0.55 or more, it was taken as a criterion for having a target profile characteristic of uneven defects, and was used as an index for distinguishing uneven defects and pigment aggregation defects.

(Example 2)
For Defect Production Examples 1-A to 1-C, the vicinity of the defect was observed by the same means as in Example 1, except that the light receiving angle was changed to 47°. Table 2 shows the results.

(Example 3)
For Defect Production Examples 1-A to 1-C, the vicinity of the defect was observed by the same means as in Example 1, except that the incident angle was changed to 63° and the light receiving angle was changed to 64°. Table 2 shows the results.

(Example 4)
For Defect Production Examples 1-A to 1-C, the vicinity of the defect was observed by the same means as in Example 1, except that the incident angle was changed to 31° and the light receiving angle was changed to 32°. Table 2 shows the results.

(Example 5)
In Example 1, the vicinity of the defect was observed by the same means as in Example 1, except that the observation object was changed to Defect Production Examples 2-A to 2-C. Table 2 shows the results.

(Example 6)
In Example 1, the vicinity of the defect was observed by the same means as in Example 1, except that the observation object was changed to Defect Production Examples 3-A to 3-C. Table 2 shows the results.

(Example 7)
In Example 1, the vicinity of the defect was observed by the same means as in Example 1, except that the observation object was changed to Defect Production Examples 4-A to 4-C. Table 2 shows the results.

(Example 8)
In Example 1, the vicinity of the defect was observed by the same means as in Example 1, except that the observation target was changed to Defect Production Examples 5-A to 5-C. Table 2 shows the results.

(Example 9)
In Example 1, the vicinity of the defect was observed by the same means as in Example 1, except that the observation object was changed to Defect Production Examples 6-A to 6-C. Table 2 shows the results.

(Example 10)
The vicinity of the defect was observed by the same means as in Example 1, except that the incident wavelength was changed to 900 nm. Table 2 shows the results.

(Example 11)
In Example 1, the vicinity of the defect was observed by the same means as in Example 1, except that the incident wavelength was changed to 1000 nm. Table 2 shows the results.

(Example 12)
The vicinity of the defect was observed by the same means as in Example 1, except that the incident wavelength was changed to 1100 nm. Table 2 shows the results.

(Comparative example 1)
The vicinity of the defect was observed by the same means as in Example 1, except that the incident angle was changed to 20° and the light receiving angle was changed to 21°. Table 3 shows the results.

(Comparative example 2)
The vicinity of the defect was observed by the same means as in Example 1, except that the incident angle was changed to 70° and the light receiving angle was changed to 71°. Table 3 shows the results.

(Comparative Example 3)
The vicinity of the defect was observed by the same means as in Example 1, except that the incident wavelength was changed to 780 nm. Table 3 shows the results.

(Comparative Example 4)
The vicinity of the defect was observed by the same means as in Example 1, except that the incident wavelength was changed to 600 nm. Table 3 shows the results.

Claims (5)

An electrophotographic photoreceptor inspection method for inspecting a cylindrical electrophotographic photoreceptor having a support, an intermediate layer and a photosensitive layer in this order using an inspection mechanism , comprising:
The inspection mechanism
a support means for rotating the electrophotographic photosensitive member , which is an object to be inspected, around its axis;
irradiating means for irradiating the electrophotographic photosensitive member with inspection light having a wavelength of 900 nm or more along the axial direction of the electrophotographic photosensitive member;
an imaging means for receiving reflected light of the inspection light reflected by the intermediate layer of the electrophotographic photosensitive member and acquiring a distribution of the reflected light ;
with
The inspection method is
rotating the electrophotographic photosensitive member about its axis by the supporting means;
a step of causing the inspection light to be incident on the electrophotographic photosensitive member at an angle of θ1° with respect to the normal line of the electrophotographic photosensitive member by the irradiation means ;
a step of receiving the reflected light at an angle of θ2° with respect to the normal line of the electrophotographic photosensitive member by the imaging means, and acquiring the distribution of the reflected light;
a step of discriminating unevenness defects of the intermediate layer from the acquired distribution of the reflected light;
has
The θ1° is 31° or more and 63° or less,
The θ2° is θ1+1° or more and θ1+2° or less ,
A method for inspecting an electrophotographic photoreceptor, characterized by: The inspection method according to claim 1 , wherein the intermediate layer has a regular reflectance of 80% or more at the wavelength of the inspection light. 3. The inspection method according to claim 1 , wherein said photosensitive layer has a charge generation layer having no absorption band in the wavelength of said inspection light. The inspection mechanism further comprises image processing means for determining the uneven defect ,
The image processing means is
an extracting means for extracting a defect candidate area in the imaging range of the imaging means ;
means having a function of extracting a projection profile of the defect candidate region, obtaining a correlation coefficient of symmetry of the accumulated profile, and discriminating the uneven defect from the shape of the intermediate layer ;
comprising a
The inspection method according to any one of claims 1 to 3 . A method for producing a cylindrical electrophotographic photoreceptor comprising a support, an intermediate layer and a photosensitive layer in this order, comprising:
A method for producing an electrophotographic photoreceptor, comprising a step of inspecting the electrophotographic photoreceptor by the inspection method according to any one of claims 1 to 4 .

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