JP4481850B2 - Surface state measuring method and surface state measuring apparatus - Google Patents

Description

  The present invention relates to a surface state measuring method and a surface state measuring apparatus capable of easily and reliably determining whether or not a light transmissive substance adheres to the surface of a light transmissive coating film.

When an electrophotographic photosensitive member having a photosensitive layer which is a light-transmitting coating film is mounted on an actual machine (electrophotographic apparatus), in general, foreign matter adheres to the surface over time, or abnormal photosensitive layer scraping occurs, The surface condition may be modified by charging or the photosensitive layer may be deteriorated.
In particular, when a foreign substance adheres to the surface of the photosensitive layer, filming occurs, and as a result, an abnormal image may be generated in the final quality image.
Further, when the coefficient of friction on the surface of the photosensitive layer increases due to use over time, the film scraping amount of the photosensitive layer increases only at that portion, and an abnormal image may be formed.
Further, when the surface deterioration of the photosensitive layer of the electrophotographic photosensitive member progresses due to electrostatic fatigue due to charging, image quality deterioration may occur.

  In order to solve these problems, a metal soap as a lubricant is applied as a protective layer on the photosensitive layer of the electrophotographic photoreceptor, and a certain amount of metal soap is supplied to maintain a uniform protective layer. It is going to continue.

  For this reason, it is expected that a region where the metal soap is not applied is generated from the phenomenon of the cleaning blade being involved in the actual machine and the filming phenomenon on the electrophotographic photosensitive member. However, there has been no effective means to evaluate the actual state of metal soap application and its uniformity, and so far it has been managed only by the amount of metal soap consumed, and it can only be grasped as a whole. There was no problem.

  As a means for measuring the presence of the coating film containing the metal soap, as an analysis method to be a destructive inspection, for example, by making full use of ATR method, XPS (X-ray photoelectron spectroscopy), etc. with an FT-IR analyzer It is possible to make a quantitative evaluation. However, in these methods, it is not easy to perform sample preparation and measure over time, and it is practically impossible to measure the entire uniformity, which is a destructive inspection. There were also many disadvantages.

  On the other hand, Patent Document 1 and the like have been proposed as an apparatus and method for determining the presence of adhesion of a substance to a carrier. However, these methods target carriers such as fine particles using the laser trap method, and is a light-transmitting substance present on the light-transmitting coating film of a device such as an electrophotographic photosensitive member? It is very difficult to determine whether or not.

JP 2003-194720 A

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, the present invention is a surface condition measurement that can reliably and easily measure whether or not a light-transmitting substance as an object to be measured exists on a light-transmitting coating film, in a non-contact and non-destructive manner. It is an object of the present invention to provide a method and a surface state measuring apparatus for carrying out the surface state measuring method.

Means for solving the problems are as follows. That is,
<1> A surface state measurement method for determining the vertical spectral surface reflectance on the surface of a light-transmitting coating film and measuring the presence or absence of a light-transmitting substance on the light-transmitting coating film,
Condensing spectral light from a light source that emits spectral light in a desired wavelength region via a focusing optical system in a confocal optical system ;
Allowing the focused light beam to enter the light-transmitting coating film so that a focused position of the focused light beam is on the surface of the light-transmitting coating film ;
Reflected light from the surface of the light-transmitting coating film is returned to the confocal optical system via the focusing optical system, and guided to the spectroscopic means by the detection light transmission fiber to be spectrally separated ;
Supplying a metal soap as the light-transmitting substance onto a photosensitive layer of an electrophotographic photosensitive member as a light-transmitting coating film;
Obtained based on the spectral intensity calculating the vertical spectral surface reflectance, and measuring the presence of the metal soap from the material-specific vertical spectral surface reflectance of said metallic soap,
It is the surface state measuring method characterized by including .
<2> The surface state measurement method according to <1>, wherein the focal depth of the focusing optical system in the confocal optical system is within ± 0.5 μm.
< 3 > The surface state measurement method according to any one of <1> to <2>, wherein the refractive index of the coating film containing metal soap is ± 0.2 or more of the refractive index of the light-transmitting coating film. .
< 4 > A surface state measuring device for determining the vertical spectral surface reflectance on the surface of the light-transmitting coating film and measuring the presence or absence of the light-transmitting substance on the light-transmitting coating film,
A light source that emits spectrum light in a desired wavelength region;
A confocal optical system including a converging optical system that condenses spectral light from the light source and focuses the condensed light flux on the surface of the light-transmitting coating film;
Spectroscopic means for returning the light reflected from the surface of the light-transmitting coating film to the confocal optical system and spectrally separating the detection light guided by the detection light transmission fiber;
Spectral intensity detection means for detecting the spectral intensity of the detection light split by the spectroscopic means;
Means for supplying a metal soap as the light-transmitting substance onto a photosensitive layer of an electrophotographic photosensitive member as a light-transmitting coating film;
Calculation means for calculating the vertical spectral surface reflectance of the metal soap as the light transmissive substance, and determining the presence of the metal soap based on the vertical spectral surface reflectance specific to the substance;
It is a surface state measuring apparatus characterized by having.
< 5 > The surface state measuring device according to < 4 >, wherein the spectral emission wavelength of the light source, the transmission wavelength of the optical system, the spectral wavelength of the spectroscopic means, and the spectral intensity detection wavelength are 200 to 850 nm.
< 6 > The surface state measuring apparatus according to any one of < 4 > to < 5 >, wherein the focusing optical system is a plan-type apochromatic objective lens.
< 7 > The surface state measurement apparatus according to any one of < 4 > to < 5 >, wherein the focusing optical system is a reflective objective lens.
< 8 > The surface state measuring apparatus according to any one of < 4 > to < 7 >, wherein the numerical aperture (NA) of the focusing optical system is 0.8 or more.
< 9 > The surface state measuring apparatus according to any one of < 4 > to < 8 >, wherein the spectroscopic unit is at least one of a diffraction grating, a prism, and a spectral filter.
< 10 > The surface state measurement device according to any one of < 4 > to < 9 >, wherein the spectrum intensity detection unit is any one of a CCD line sensor and a silicon photodiode array.

  According to the present invention, conventional problems can be solved, and the presence or absence of adhesion of a light-transmitting substance on a light-transmitting coating film such as an electrophotographic photosensitive member can be easily and reliably determined with high accuracy. It is an object of the present invention to provide a surface state measuring method and a surface state measuring apparatus for carrying out the surface state measuring method.

(Surface condition measuring method and surface condition measuring apparatus)
The surface state measurement method of the present invention is a surface state measurement in which the vertical spectral surface reflectance of the surface of the light-transmitting coating film as the object to be measured is obtained and the presence or absence of a light-transmitting substance on the surface of the light-transmitting coating film A method,
Spectral light from a light source that emits spectral light in a desired wavelength region is condensed through a converging optical system in the confocal optical system so that the focused position of the condensed light flux becomes the surface of the light-transmitting coating film The condensed light beam is incident on the light-transmitting coating film, and the reflected light from the surface of the light-transmitting coating film is returned to the confocal optical system via the focusing optical system, and is dispersed by a detection light transmission fiber. And calculating the vertical spectral surface reflectance based on the obtained spectral spectral intensity and measuring the presence of the light transmissive material from the vertical spectral surface reflectance specific to the material, and if necessary It includes other steps.
The surface state measurement apparatus of the present invention obtains the vertical spectral surface reflectance of the surface of the light-transmitting coating film as the object to be measured, and measures the presence or absence of the light-transmitting substance on the surface of the light-transmitting coating film The apparatus includes a light source, a confocal optical system, a spectroscopic unit, a spectral intensity detection unit, and a calculation unit, and further includes other units as necessary.

  The surface state measuring method of the present invention can be preferably implemented using the surface state measuring apparatus of the present invention. In addition, when the said surface state measuring apparatus of this invention is implemented, it will implement the said surface state measuring method of this invention.

  Here, the “desired wavelength region” of the spectrum light from the light source means a wavelength region that enables measurement of the vertical spectral surface reflectance of the light-transmitting coating film and the light-transmitting known substance, Although it is determined by the physical properties of the light-transmitting coating film and the light-transmitting known substance (for example, metal soap), for example, the spectral emission wavelength of the light source is preferably 200 to 850 nm. This is because the optical absorption edge of a general metal soap is present in the region of 200 to 300 nm because of the energy band gap, and therefore the measurement wavelength range is preferably 200 nm or more. The vertical spectral surface reflectance may be in the wavelength region where the complex refractive index is larger than that of air, and is more preferably in the range of 400 to 850 nm. Similarly, the transmission wavelength of the optical system, the spectral wavelength of the spectroscopic means, and the spectral intensity detection wavelength are preferably in the wavelength range of 200 to 850 nm.

  The metal soap is not particularly limited and may be appropriately selected depending on the intended purpose. For example, zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, zinc oleate, zinc palmitate, magnesium palmitate Zinc myristate, zinc laurate, zinc behenate, and the like. Among these, zinc stearate is particularly preferable.

  In this case, the reflected light from the surface of the light-transmitting coating film is returned to the confocal optical system via the focusing optical system in a state where the focal point of the focused light is the surface of the light-transmitting coating film, and the detection light The light is guided to the spectroscopic means by the transmission fiber and dispersed. The vertical spectral surface reflectance is calculated based on the spectral spectral intensity obtained by spectroscopy, and the presence / absence of a light-transmitting substance is determined according to the vertical spectral surface reflectance specific to the substance.

In the surface state measuring method of the present invention, the object to be measured is a photosensitive layer in an electrophotographic photosensitive member by setting the focal depth of the converging optical system within ± 0.5 μm. Even so, only the surface substance information can be extracted, and a good surface state can be measured.
The depth of focus depends on the wavelength of incident light, and is determined from the numerical aperture (NA) that is an optical characteristic of the objective lens of the confocal optical system.

  The object to be measured in the surface state measurement method of the present invention is not particularly limited and can be appropriately selected according to the purpose. For example, a metal soap coating film is formed on the surface of the photosensitive layer which is a light-transmitting coating film. An electrophotographic photosensitive member provided with is suitable. In this case, the presence of the metal soap on the light-transmitting coating film can be measured by measuring the surface of the electrophotographic photosensitive member at multiple points.

The object to be measured is an electrophotographic photosensitive member in which a coating film containing metal soap is provided on the surface of a light-transmitting coating film, and the refractive index of the coating film of the metal soap is the refractive index of the light-transmitting coating film. Is preferably ± 0.2 or more. Thereby, presence of metal soap can be measured with high accuracy.
That is, the refractive index difference has a relationship in which the interface reflection decreases as the refractive index difference between the media decreases, and the interface reflectance increases as the refractive index difference between the objects increases. Therefore, if the difference in refractive index between the light-transmitting coating film determined from the band structure of the electron energy of the substance and the coating film containing metal soap is ± 0.2 or more, the difference in vertical spectral surface reflectance with a sufficiently significant difference And the presence of the metal soap on the light-transmitting coating film can be easily measured.

Here, the electrophotographic photosensitive member as the object to be measured will be described.
The photoreceptor has a photosensitive layer on a substrate, and further has other layers as necessary.
As the photoconductor, in the first embodiment, a substrate and a single-layer type photosensitive layer are provided on the substrate, and further a protective layer, an intermediate layer, and other layers are provided as necessary.
In the second embodiment, the photoconductor is provided with a base, and a laminated photosensitive layer having at least a charge generation layer and a charge transport layer in this order on the base. It has a layer, an intermediate layer, and other layers. In the second embodiment, the charge generation layer and the charge transport layer may be laminated in reverse.

-Substrate-
The substrate is not particularly limited as long as it has conductivity, and can be appropriately selected according to the purpose. For example, a conductor or an insulator subjected to a conductive treatment is suitable. For example, Al, Ni , Fe, Cu, metal such as Au, or alloys thereof; polyesters, polycarbonates, polyimides, Al on an insulating substrate such as glass, Ag, metal such as Au or _{an in} 2 _O 3, conductive material SnO ₂ or the like, A resin substrate in which carbon black, graphite, metal powder such as Al, Cu, Ni, etc., conductive glass powder, etc. are uniformly dispersed in the resin to impart conductivity to the resin, and subjected to a conductive treatment. Paper, etc.

  There are no particular restrictions on the shape and size of the substrate, and any of a plate shape, a drum shape, or a belt shape can be used. However, when a belt-shaped substrate is used, it is necessary to provide a driving roller and a driven roller inside. However, there are merits such as increasing the degree of freedom of layout while making the device complicated and large.

-Multilayer type photosensitive layer-
The multilayer photosensitive layer has at least a charge generation layer and a charge transport layer in this order, and further includes a protective layer, an intermediate layer, and other layers as necessary.

  The charge generation layer includes at least a charge generation material, and includes a binder resin and, if necessary, other components.

  There is no restriction | limiting in particular as said charge generation substance, Although it can select suitably according to the objective, Either an inorganic material and an organic material can be used.

  The inorganic material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include crystalline selenium, amorphous-selenium, selenium-tellurium, selenium-tellurium-halogen, and selenium-arsenic compounds. It is done.

  There is no restriction | limiting in particular as said organic type material, According to the objective, it can select suitably according to the objective, For example, C.I. Pigment Blue 25 (Color Index CI.21180), C.I. Pigment Red 41 ( CI 21200), CI Acid Red 52 (CI 45100), CI Basic Red 3 (CI 45210), azo pigments having a carbazole skeleton, azo pigments having a distyrylbenzene skeleton, triphenylamine Azo pigments having a skeleton, azo pigments having a dibenzothiophene skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a fluorenone skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, di Has a styrylcarbazole skeleton Azo pigments such as Zo pigment; phthalocyanine pigments such as C.I. Pigment Blue 16 (C.I. 74100); indigo such as C. I.But Brown (C.I. 73410), C.I. Pigments; perylene pigments such as Argol Scarlet 5 (manufactured by Bayer), Indusence Scarlet R (manufactured by Bayer); and squalic dyes. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, a polyamide resin, a polyurethane resin, an epoxy resin, a polyketone resin, a polycarbonate resin, a silicone resin, an acrylic resin, a polyvinyl butyral resin, polyvinyl Formal resin, polyvinyl ketone resin, polystyrene resin, poly-N-vinyl carbazole resin, polyacrylamide resin, and the like can be given. These may be used individually by 1 type and may use 2 or more types together.

  Note that a charge transport material may be added as necessary. In addition to the binder resin described above, a polymer charge transport material can be added as the binder resin for the charge generation layer.

As a method for forming the charge generation layer, a vacuum thin film preparation method and a casting method from a solution dispersion system can be mentioned.
Examples of the former method include a glow discharge polymerization method, a vacuum deposition method, a CVD method, a sputtering method, a reactive sputtering method, an ion plating method, and an accelerated ion injection method. This vacuum thin film manufacturing method can satisfactorily form the inorganic material or organic material described above.
In order to provide the charge generation layer by the latter casting method, a charge generation layer forming coating solution is used and a conventional method such as a dip coating method, a spray coating method, or a bead coating method is used. Can do.

The organic solvent used for the charge generation layer forming coating solution is not particularly limited and may be appropriately selected depending on the intended purpose. For example, acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene , Chloroform, dichloromethane, dichloroethane, dichloropropane, trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, ethyl cellosolve, propyl cellosolve, Etc. These may be used individually by 1 type and may use 2 or more types together.
Among these, tetrahydrofuran, methyl ethyl ketone, dichloromethane, methanol, and ethanol having a boiling point of 40 ° C. to 80 ° C. are particularly preferable because they can be easily dried after coating.
The charge generation layer forming coating solution is produced by dispersing and dissolving the charge generation material and a binder resin in the organic solvent. Examples of the method for dispersing the organic pigment in the organic solvent include a dispersion method using a dispersion medium such as a ball mill, a bead mill, a sand mill, and a vibration mill, and a high-speed liquid collision dispersion method.

  The thickness of the charge generation layer is usually preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm.

  The charge transport layer is a layer intended to hold a charged charge and to couple the charge generated and separated in the charge generation layer by exposure to the charged charge held by movement. In order to achieve the purpose of holding the charged charge, it is required that the electric resistance is high. Further, in order to achieve the purpose of obtaining a high surface potential with the charged charge that has been held, it is required that the dielectric constant is small and the charge mobility is good.

  The charge transport layer includes at least a charge transport material, and includes a binder resin and, if necessary, other components.

Examples of the charge transport material include a hole transport material, an electron transport material, and a polymer charge transport material.
Examples of the electron transporting material (electron accepting material) include chloranil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro. -9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the hole transport material (electron donating material) include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4 -Dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, etc. It is done. These may be used individually by 1 type and may use 2 or more types together.

Examples of the polymer charge transport material include those having the following structure.
(A) Polymer having carbazole ring For example, poly-N-vinylcarbazole, JP-A-50-82056, JP-A-54-9632, JP-A-54-11737, JP-A-4-175337 And the compounds described in JP-A-4-183719 and JP-A-6-234841.
(B) Polymer having hydrazone structure For example, JP-A-57-78402, JP-A-61-20953, JP-A-61-296358, JP-A-1-134456, JP-A-1-134456 179164, JP-A-3-180851, JP-A-3-180852, JP-A-3-50555, JP-A-5-310904, JP-A-6-234840, etc. Is done.
(C) Polysilylene polymer For example, JP-A-63-285552, JP-A-1-88461, JP-A-4-264130, JP-A-4-264131, JP-A-4-264132, Examples thereof include compounds described in Kaihei 4-264133 and JP-A-4-289867.
(D) Polymer having a triarylamine structure For example, N, N-bis (4-methylphenyl) -4-aminopolystyrene, JP-A-1-134457, JP-A-2-282264, JP-A-2- Examples include compounds described in JP-A-304456, JP-A-4-133605, JP-A-4-133066, JP-A-5-40350, and JP-A-5-202135.
(E) Other polymers For example, formaldehyde condensation polymer of nitropyrene, JP-A-51-73888, JP-A-56-150749, JP-A-6-234836, JP-A-6-234837 The described compounds and the like are exemplified.

  In addition to the above, the polymer charge transporting material includes, for example, a polycarbonate resin having a triarylamine structure, a polyurethane resin having a triarylamine structure, a polyester resin having a triarylamine structure, and a triarylamine structure. And a polyether resin. Examples of the polymer charge transporting material include JP-A 64-1728, JP-A 64-13061, JP-A 64-19049, JP-A-4-11627, JP-A 4-116627. 2225014, JP-A-4-230767, JP-A-4-320420, JP-A-5-232727, JP-A-7-56374, JP-A-9-127713, JP-A-9-222740. And compounds described in JP-A-9-265197, JP-A-9-211877, JP-A-9-30495, and the like.

  Examples of the polymer having an electron donating group include not only the above-mentioned polymer but also a copolymer with a known monomer, a block polymer, a graft polymer, a star polymer, It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-109406.

Examples of the binder resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, polystyrene resin, phenol resin, epoxy resin, polyurethane resin, polyvinylidene chloride resin, Examples thereof include alkyd resins, silicone resins, polyvinyl carbazole resins, polyvinyl butyral resins, polyvinyl formal resins, polyacrylate resins, polyacrylamide resins, and phenoxy resins. These may be used individually by 1 type and may use 2 or more types together.
The charge transport layer may also contain a copolymer of a crosslinkable binder resin and a crosslinkable charge transport material.

  The charge transport layer can be formed by dissolving or dispersing these charge transport materials and a binder resin in an appropriate solvent, and applying and drying them. In addition to the charge transport material and the binder resin, an appropriate amount of additives such as a plasticizer, an antioxidant, and a leveling agent may be added to the charge transport layer as necessary.

  There is no restriction | limiting in particular in the thickness of the said charge transport layer, According to the objective, it can select suitably, 5-100 micrometers is preferable and 5-30 micrometers is more preferable.

-Single layer photosensitive layer-
The single-layer type photosensitive layer includes a charge generation material, a charge transport material, a binder resin, and other components as necessary.
As the charge generating substance, charge transporting substance, and binder resin, the above-described materials can be used.
As said other component, a plasticizer, microparticles | fine-particles, various additives, etc. are mentioned, for example.

  The thickness of the single-layer type photosensitive layer is preferably 5 to 100 μm, and more preferably 5 to 50 μm. When the film thickness is less than 5 μm, the chargeability may decrease, and when it exceeds 100 μm, the sensitivity may decrease.

A protective layer may be provided on the photosensitive layer as necessary. The protective layer contains at least a binder resin, a charge transport material, and, if necessary, other components.
As the pre-binder resin and the charge transport material, the above-described materials can be used.
Various additives may be added to the protective layer as necessary for the purpose of improving adhesiveness, smoothness, and chemical stability.
There is no restriction | limiting in particular in the thickness of the said protective layer, According to the objective, it can select suitably, For example, 1-15 micrometers is preferable and 1-10 micrometers is more preferable.

  An undercoat layer may be provided between the substrate and the photosensitive layer as necessary. The undercoat layer is provided for the purpose of improving adhesiveness, preventing moire, improving the coatability of the upper layer, and reducing residual potential.

The undercoat layer contains at least a resin and fine powder, and further contains other components as necessary.
Examples of the resin include water-soluble resins such as polyvinyl alcohol resin, casein, and sodium polyacrylate; alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon; polyurethane resins, melamine resins, alkyd-melamine resins, and epoxy resins. And a curable resin that forms a three-dimensional network structure.
Examples of the fine powder include metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide, metal sulfides, and metal nitrides.
There is no restriction | limiting in particular about the thickness of the said undercoat layer, According to the objective, it can select suitably, 0.1-10 micrometers is preferable and 1-5 micrometers is more preferable.

In the photoreceptor, an intermediate layer may be provided on the substrate as necessary in order to improve adhesion and charge blocking properties. The intermediate layer contains a resin as a main component, and it is desirable that these resins are resins having a high solvent resistance with respect to an organic solvent in view of applying a photosensitive layer thereon with a solvent.
As the resin, the same resin as the above undercoat layer can be appropriately selected and used.

  Next, the surface state measuring apparatus of the present invention is an apparatus for performing the surface state measuring method of the present invention, and includes a light source, a confocal optical system including a focusing optical system, a detection light transmission fiber, and a spectroscopic device. Means, a spectrum intensity detecting means, and a calculating means, and further having other means as required.

The light source is not particularly limited as long as it can emit spectrum light in a desired wavelength region, and can be appropriately selected according to the purpose. Examples thereof include a deuterium bulb and a halogen bulb dual light source. It is done.
As described above, the spectral emission wavelength of the light source is preferably in the wavelength range of 200 to 850 nm.

The confocal optical system including the focusing optical system can block light information from a position other than the focused position in focus at the confocal pinhole, and can extract only surface area information.
The focusing optical system collects the light from the light source as part of the confocal optical system and collects the condensed light flux toward the surface of the light-transmitting coating film.
As the focusing optical system, for example, a plan type apochromatic objective lens is preferably used.
In this way, the objective lens used in the focusing optical system is a plan-type apochromat lens, so that the chromatic aberration at the time of condensing and receiving light can be completely removed in the visible range with the image plane close to flat, and high condensing. And spectral spectrum intensity with good accuracy and wavelength accuracy can be detected.

  A reflective objective lens is preferably used as the focusing optical system. This is because a refractive objective lens has a narrow wavelength range that can be handled and it is difficult to correct chromatic aberration. However, problems such as transmittance and chromatic aberration can be solved by using the reflective objective lens, so that wavelength detection accuracy is good. This is because the spectral spectrum intensity can be detected.

The numerical aperture (NA) of the focusing optical system is preferably 0.8 or more, and more preferably 0.9 to 0.95.
In general, the larger the numerical aperture, the shallower the depth of focus. In the case of a confocal optical system, it is possible to extract physical property information only on the surface of a light-transmitting film. Conversely, when the depth of focus becomes deep, that is, when the numerical aperture is small, the depth of focus becomes deep. In this case, the influence of the information component in the film is picked up as noise.
As will be apparent from the experiment described later, by using an objective lens having a numerical aperture (NA) of 0.8 or more, the substance information from the surface of the light-transmitting coating film of the electrophotographic photosensitive member or the metal soap coating film is high. It has been confirmed that it can be secured by SN.

The spectroscopic means is means for spectroscopically analyzing the detection light reflected by the surface of the light-transmitting coating film as an object to be measured and transmitted by the detection light transmission fiber through the confocal pinhole.
As the spectroscopic means, for example, at least one of a diffraction grating, a prism, and a spectroscopic filter can be suitably used. As the spectroscopic means such as the diffraction grating, a rotating type that changes the spectral wavelength region by rotation can be used, but a fixed spectroscopic means (such as a diffraction grating used spatially fixed) is used. If used, a space for rotation and a rotation mechanism are not required, and the surface state measuring device can be made compact. In addition, it is also possible to mount on an actual machine (image forming apparatus) as a state sensing technique.

  The spectrum intensity detection means is means for detecting the spectrum intensity of the detection light dispersed by the spectroscopy means.

As the spectral intensity detection means, for example, a CCD line sensor, a silicon photodiode array in which silicon photodiodes are arranged at predetermined spectral wavelength positions, and the like can be suitably used.
The CCD line sensor and the silicon photodiode have high sensitivity, and have sufficient measurement sensitivity even in weak measurement using a confocal optical system or a microscope optical system. Further, since it is small, light, and inexpensive, for example, the circuit configuration is simple even when the surface state measuring device is incorporated in the image forming apparatus.

The computing means is means for calculating the vertical spectral surface reflectance from the detected spectral spectrum intensity and determining the presence / absence of a light-transmitting substance based on the vertical spectral surface reflectance specific to the substance.
Examples of the calculation means include devices such as a sequencer, a calculation circuit, and a computer.

  Here, one mode for carrying out the surface texture measuring method of the present invention by the surface texture measuring apparatus of the present invention will be described with reference to FIG. FIG. 1 is an explanatory view showing only an essential part of the embodiment of the surface state measuring apparatus.

In FIG. 1, a coating film of a light-transmitting substance indicated by reference numeral 8 is coated and held on the light-transmitting coating film 1 and set on the measurement optical axis of the confocal optical system.
As the light-transmitting coating film 1, films having various configurations can be used.
The object to be measured on which the “light-transmitting coating film” to be measured in the surface state measuring method of the present invention is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include those having a light-transmitting coating film formed thereon.

Two typical examples of the configuration of the object to be measured are as shown in FIG. 2A, in which an intermediate layer 3 is formed on an aluminum drum 2 as a substrate, and a charge generation layer 4 and a charge are formed on the intermediate layer. The transport layer 5 is laminated and the surface layer 7 is further formed. The charge generation layer 4, the charge transport layer 5 and the surface layer 7 form a photosensitive layer.
On the other hand, as shown in FIG. 2B, an intermediate layer 3 is formed on an aluminum drum 2 as a substrate, and a charge generation layer 4 and a charge transport layer 5 are laminated on the intermediate layer to form a photosensitive layer. .

2A and 2B, the intermediate layer 3 has a function as a binder for adhering and fixing the photosensitive layer to the conductive substrate, and contains fine particles of pigment in order to suppress adverse effects such as uneven charging.
2A and 2B, the charge generation layer 4 is a layer that generates a “positive / negative charge pair” by irradiation with a specific wavelength, and the charge transport layer 5 has a predetermined polarity of the charges generated in the charge generation layer 4. It has a function to transport the product to the surface of the photosensitive layer.
In FIG. 2A, the surface layer 7 is formed by dispersing reinforcing filler fine particles on the surface side of the charge transport layer 5. Therefore, the surface layer 7 in FIG. 2A is a dispersion system of the material substance of the charge transport layer and the filler fine particles.

  2A and 2B, the thickness of the intermediate layer is preferably 2 to 6 μm. The thickness of the charge generation layer is preferably 1 μm or less. The thickness of the charge transport layer is preferably 15 to 35 μm. The thickness of the surface layer is preferably 3 to 6 μm. Accordingly, the total thickness of the photosensitive layer is preferably 19 to 42 μm.

  Next, in the surface state measurement apparatus 6 shown in FIG. 1, a light source 61 that emits spectrum light in a desired wavelength region, and a Kohler illumination system 62 for guiding the light from the light source 61 to the measured object side are provided. An objective that constitutes a confocal optical system that emits light that has passed through the microscope optical system and the confocal optical system 63 toward the object to be measured and condenses it toward the light-transmitting coating film that is the object to be measured. Reflected by the lens 64 and the DUT 1 or 8 and transmitted by the detection light transmission fiber 65 through the objective lens 64, the confocal optical system 63, and the confocal pinhole 71 which is a part of the confocal optical system. Spectroscopic means 66 for spectrally separating the light, spectral intensity detection means 67 for detecting the spectral intensity of the detection light split by the spectroscopic means 66, and arithmetic means for calculating the vertical spectral surface reflectance based on the spectral spectral intensity And a 8 is configured to be vertically incident on the surface of the object with irradiation light.

  The objective lens 64 serving as the focusing optical system has a numerical aperture (NA) of 0.8 or more. In this embodiment, a “plan type fluorite lens” (OLYMPUS LM Plan FL-BD 100 ×) having a magnification of 100 ×, a working distance of 3.4 mm, and a focal depth of ± 0.43 μm is used. The objective lens 64 is fixed to the confocal optical system 63, and the confocal optical system 63 also holds the emission side end of the fiber probe 65.

  The light source 61 is a dual light source of a deuterium lamp and a halogen-tungsten lamp, and emits spectrum light in a wide wavelength range from the ultraviolet region to the near infrared region. The emitted light is guided to the measurement object 8 or 1 through the confocal optical system.

  The spectroscopic means 66 is a diffraction grating, specifically, a fixed-type Zernitana diffraction grating having a spectral region of 200 to 1000 nm. As the spectroscopic means 66, as described above, a prism or a spectroscopic filter can be used instead of the diffraction grating.

  The spectral intensity detection means 67 is a silicon photodiode array. This silicon photodiode array has sensitivity in the wavelength range of the ultraviolet region to 1000 nm, and has a number of light receiving elements of 1024.

Next, the principle of measuring whether or not a coating film containing metal soap exists on the surface of the photosensitive layer, which is a light-transmitting coating film of the electrophotographic photosensitive member, will be described with reference to FIG. 2B.
As described above, the light-transmitting coating film is composed of the charge generation layer 4 and the charge transport layer 5. The metal soap coating film 8 formed on the surface of the light-transmitting coating film is obtained by uniformly coating the charge transport layer 5 and zinc stearate having a refractive index difference of ± 0.2 or more.

Generally, an individual and a substance are classified into three types, that is, a metal, a semiconductor, or an insulator depending on the difference in electrical properties. For example, in the case of a semiconductor, since the energy of electrons has a band structure, the optical transition from the valence band to the conduction band determines “light absorption” and “reflection”.
Therefore, if the energy of incident light is larger than the band gap energy, electrons can be transitioned from the valence band to the conduction band, and light absorption occurs.
On the other hand, when there is strong absorption, the dielectric constant due to electronic polarization increases, so the refractive index increases and the vertical spectral surface reflectance also increases. That is, the light absorption (optical absorption edge) and the vertical spectral surface reflectance are values specific to the substance.

  Here, even in an insulator such as a metal soap, the main cause of light absorption is interband transition. That is, when the charge transport layer 5 is an organic material like an OPC photoconductor for electrophotography, this corresponds to a large energy difference when electrons move from HOMO (High Occupied Molecular Orbital) to LUMO (Lowest Occupied Molecular Orbital). It absorbs light (ultraviolet rays). Since light absorption does not occur for light of lower energy (long wavelength light longer than the visible range), it is generally colorless and transparent.

Regarding the confirmation of the optical absorption edge, which is a substance eigenvalue, the most accurate determination is to measure the spectral reflectance or spectral transmittance.
The phenomenon of reflection occurs when there is a difference in refractive index or extinction coefficient, which is a complex refractive index, between air and the charge transport layer 5 or between air and the zinc stearate coating film 8. Reflection occurs when there is a difference in refractive index or extinction coefficient (complex refractive index).

Assuming that the vertical surface reflectivity R at an arbitrary wavelength when light is vertically incident and received vertically, the refractive index of the charge transport layer 5 or the zinc stearate coating film 8 is n1, the extinction coefficient is K, and the refraction of air If the rate is 1.0, it can be calculated by the following formula 1. That is, if there is no influence such as scattering or can be ignored, it can be seen that the spectral vertical surface reflectance varies depending on the difference in the complex refractive index of the substance.
<Formula 1>
R = ((n1-1) ² + K ² ) / (n1 + 1) ² + K ² ))

  The charge transport layer 5 has a refractive index of 1.7 and an extinction coefficient of 0. In this case, since the refractive index of zinc stearate 3 is 1.43 and the extinction coefficient is almost zero, the refractive index difference is in the range of ± 0.2 or more, and by accurately measuring the vertical spectral surface reflectance, The vertical spectral surface reflectance near 500 nm on the surface of the charge transport layer is 6%, and the vertical spectral surface reflectance of the zinc stearate coating film is 3%. Thus, for example, if a threshold is provided for the vertical spectral surface reflectance of 4.5%, the presence of the zinc stearate film can be determined.

In this case, since both the charge transport layer 5 and the zinc stearate coating film 8 are light-transmitting coating films, it is optically necessary to extract only surface material information.
In general, when light is applied to a light-transmitting coating film, surface reflected light reflected on the coating film surface and light reflected and transmitted inside the coating film and reflected on the internal interface are simultaneously observed.
The light from the inside beyond a certain depth is irrelevant to the presence judgment of the metal soap coating film, and therefore the light from the inside becomes a noise signal.

  A confocal optical system is used as an optical system for solving this problem. The confocal optical system is an optical system in which one point (in-focus position) of the sample and the confocal pinhole are in a conjugate relationship, and light from a point other than the in-focus position is blocked in the confocal pinhole, and the spectrum Does not enter the detection means. Since the optical information and scattered light before and after the in-focus position can be cut with a confocal pinhole, it is possible to acquire the optical properties of the extremely shallow surface area with high accuracy.

In this example, it was possible to determine the presence of a zinc stearate film having a thickness of 12 to 300 nm with a confocal optical system having a focal depth of 0.3 μm.
In addition, in order to eliminate the influence of scattering due to curvature and surface roughness, the vertical spectral reflectance reflectance measurement is affected by scattering due to the beam diameter being reduced to several μm or by the Mie scattering and Rayleigh scattering mechanisms. If light having a wavelength sufficiently larger than the difficult surface roughness is used, the reflectance is hardly lowered.

  FIG. 3 shows vertical spectral surface reflectance data on the surface of the charge transport layer 5 detected by the spectral intensity detection means 67 as described above. FIG. 4 shows the result of measuring the vertical spectral surface reflectance on the surface coated with the zinc stearate coating film. As shown in FIGS. 3 and 4, the vertical spectral surface reflectance has a significant difference in the vertical spectral surface reflectance over a wavelength region of 450 to 800 nm due to the difference in optical physical properties.

  Such a significant difference in the vertical spectral surface reflectance is a result of "difference in optical properties of resin constituting the charge transport layer and zinc stearate, which is a metal soap". By measuring in the axial direction and the circumferential direction of the photoreceptor, it is possible to know the actual coating state of zinc stearate and its uniformity.

Also, in the ultraviolet region where the energy of light increases, the maximum absorption wavelength differs between the charge transport layer and zinc stearate due to the difference in the optical absorption edge, and it is possible to separate the two well in terms of vertical spectral surface reflectance. Become.
If only the charge transport layer is used, when the resin is a polymer composed of CH, the energy gap is generally in the ultraviolet region, so most of them are colorless and transparent in the visible region. Of course, if there is donor absorption, it will be reflected.
When zinc stearate is present, there is a reflectance dip, that is, an optical absorption edge, in the ultraviolet region of 200 to 250 nm wavelength.

  As described above, according to the surface state measuring method and the surface state measuring apparatus of the present invention, the light passing through the confocal optical system 63 having the objective lens 64 is condensed on the light-transmitting coating film of the object 8 or 1 to be measured. ing. In this way, instead of condensing using a confocal optical system including a focusing optical system, using a microspectroscopic reflectance measuring apparatus that does not use a confocal optical system, a light transmissive coating film or a light transmissive film is used. When reflected light from a known substance is received, the spectral reflection spectrum from the charge generation layer, which is the lower layer, is superimposed, and the vertical spectral surface reflectance on the accurate surface cannot be measured, so that the light transmission is known. The existence of the substance could not be known.

  As described above, the surface state measuring method of the present invention is a method for measuring the presence of a light-transmitting known substance on a light-transmitting coating film by the surface state measuring apparatus of the present invention, The light from the light source 61 that emits the wavelength spectrum light of the region is condensed by the converging optical system of the confocal optical system 63, and this condensed light beam is vertically incident on the object 8 or 1 to be measured and condensed. The reflected light from the light-transmitting coating film or the light-transmitting known material surface is returned to the end face of the detection light transmission fiber 65 through the objective lens 64, the confocal optical system 63, and the confocal pinhole 71, The detection light transmission fiber 65 guides the light to the spectroscopic means 66 for spectral separation, and the vertical spectral surface reflectance can be calculated and calculated based on the spectral spectral intensity.

  According to the surface state measuring method and surface state measuring apparatus of the present invention, it is possible to reliably and easily measure whether or not a light transmissive substance is present on the surface of the light transmissive coating film in a non-contact and non-destructive manner. For example, it is suitable for a method for measuring the presence of a coating film containing a metal soap on the surface of a photosensitive layer of an electrophotographic photosensitive member, a method for measuring the presence of a spent substance on a carrier resin coating film for electrophotography, and the like. Used.

FIG. 1 is a schematic view showing an example of the surface state measuring apparatus of the present invention. FIG. 2A is a schematic view showing an example of an electrophotographic photosensitive member that is an object to be measured of the present invention. FIG. 2B is a schematic view showing another example of an electrophotographic photosensitive member which is an object to be measured of the present invention. FIG. 3 is a diagram showing vertical spectral surface reflectance data on the surface of the charge transport layer detected by the spectral intensity detection means. FIG. 4 is a diagram showing vertical spectral surface reflectance data on the surface of the zinc stearate coating layer. FIG. 5 is a diagram of a spectral reflection spectrum measured using a microspectroscopic reflectance measuring apparatus that does not use a confocal optical system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light transmission coating film 2 Base | substrate 3 Intermediate | middle layer 4 Charge generation layer 5 Charge transport layer 6 Surface state measuring apparatus 7 Surface layer 8 Measured object 61 Light source 62 Kohler illumination system 63 Confocal optical system 64 Objective lens 65 For detection light transmission Fiber 66 Spectral means 67 Spectral intensity detection means 68 Calculation means

Claims (10)

A surface state measurement method for determining the vertical spectral surface reflectance on the surface of the light-transmitting coating film and measuring the presence or absence of the light-transmitting substance on the light-transmitting coating film,
Condensing spectral light from a light source that emits spectral light in a desired wavelength region via a focusing optical system in a confocal optical system ;
Allowing the focused light beam to enter the light-transmitting coating film so that a focused position of the focused light beam is on the surface of the light-transmitting coating film ;
Reflected light from the surface of the light-transmitting coating film is returned to the confocal optical system via the focusing optical system, and guided to the spectroscopic means by the detection light transmission fiber to be spectrally separated ;
Supplying a metal soap as the light-transmitting substance onto a photosensitive layer of an electrophotographic photosensitive member as a light-transmitting coating film;
Obtained based on the spectral intensity calculating the vertical spectral surface reflectance, and measuring the presence of the metal soap from the material-specific vertical spectral surface reflectance of said metallic soap,
Surface state measuring method which comprises a.   The surface state measuring method according to claim 1, wherein the focal depth of the focusing optical system in the confocal optical system is within ± 0.5 μm. The surface state measuring method according to claim 1, wherein the refractive index of the coating film containing metal soap is ± 0.2 or more of the refractive index of the light-transmitting coating film. A surface state measuring device for determining the vertical spectral surface reflectance on the surface of the light-transmitting coating film and measuring the presence or absence of the light-transmitting substance on the light-transmitting coating film,
  A light source that emits spectrum light in a desired wavelength region;
  A confocal optical system including a converging optical system that condenses spectral light from the light source and focuses the condensed light flux on the surface of the light-transmitting coating film;
  Spectroscopic means for returning the light reflected from the surface of the light-transmitting coating film to the confocal optical system and spectrally separating the detection light guided by the detection light transmission fiber;
  Spectral intensity detection means for detecting the spectral intensity of the detection light split by the spectroscopic means;
  Means for supplying a metal soap as the light-transmitting substance onto a photosensitive layer of an electrophotographic photosensitive member as a light-transmitting coating film;
  Calculation means for calculating the vertical spectral surface reflectance of the metal soap as the light transmissive substance, and determining the presence of the metal soap based on the vertical spectral surface reflectance specific to the substance;
A surface state measuring apparatus comprising: The surface state measurement apparatus according to claim 4, wherein the spectral emission wavelength of the light source, the transmission wavelength of the optical system, the spectral wavelength of the spectroscopic means, and the spectral intensity detection wavelength are 200 to 850 nm. 6. The surface state measuring apparatus according to claim 4, wherein the focusing optical system is a plan type apochromatic objective lens. 6. The surface state measuring apparatus according to claim 4, wherein the focusing optical system is a reflective objective lens. The surface state measuring apparatus according to claim 4, wherein the numerical aperture (NA) of the focusing optical system is 0.8 or more. 9. The surface state measuring apparatus according to claim 4, wherein the spectroscopic means is at least one of a diffraction grating, a prism, and a spectroscopic filter. The surface state measuring apparatus according to any one of claims 4 to 9, wherein the spectrum intensity detecting means is one of a CCD line sensor and a silicon photodiode array.