JP2002365817A - Method of measuring film thickness of surface layer of electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method of measuring the film thickness of the surface layer of an electrophotographic photoreceptor which is unaffected by the light diffusion of fillers, suitable for measurement of a layer to be measured smaller in light absorption quantity and capable of measuring the film thickness of the surface layer even in a laminated state. SOLUTION: In measuring the film thickness of the surface layer dispersed with the fillers by using an opto-thermal conversion effect, the coefficient of absorption of the surface layer dispersed with the fillers is determined and the presence or absence of the film quality which is the target for the film thickness measurement is checked. The thermal exciting light intermittently modulated at the prescribed periods determined by the thermal property values of the surface layer in which the filler is dispersed is made incident and the measurement of the film thickness is made by detecting the amplitude value of the generated acoustic weaves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the thickness of a surface layer of an electrophotographic photosensitive member having a surface layer in which an inorganic or organic filler is dispersed, and more particularly to a measurement method using a photothermal conversion (photoacoustic) effect.

[0002]

2. Description of the Related Art The thickness measurement of the surface layer of a multi-layer electrophotographic photosensitive member of a function-separated type has been conventionally performed by a gravimetric method, an eddy current method, an infrared absorption method, an infrared reflectance measurement method, and a spectral reflectance measurement. The law has been studied.

Of these methods, the most frequently used method utilizing the light interference phenomenon is to apply white parallel light to a surface layer at an arbitrary incident angle, receive reflected light or transmitted light from a thin film, and receive light. This is based on the principle that the film thickness is calculated by obtaining adjacent maximum or minimum wavelengths of the spectral intensity distribution obtained by dispersing the obtained interference light.

However, in these techniques, it is not technically easy to measure a laminated state in which an undercoat layer containing a light-scattering substance or a pigment layer is provided in a lower layer, and it is difficult to diffuse irradiation light such as an inorganic or organic filler. Even if a light scattering substance is present in the surface layer, the incident light is scattered by the filler and the transmittance of the film is reduced, so that the light interference phenomenon cannot be used,
In addition, other optical methods have a problem in that measurement is fundamentally difficult due to light scattering / concealing effects and the like, and sensitivity is lowered. Furthermore, when a conductive material is contained in the undercoat layer, it has been difficult to detect by an eddy current method.

[0005] In addition, there are some methods, such as the weight measurement method, which require time and labor and are not suitable for real-time measurement. For example, when the thickness of the surface layer in which the filler is dispersed is as thin as 5 μm or less, or when a coating film is formed on a metal housing having a curvature, or when a filler having a large reflectance is included, or the film has transparency. If not, the S / N ratio decreases with the infrared absorption type measuring means and the above-mentioned various measuring methods, and practical thickness accuracy cannot be obtained.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and is suitable for measurement of a layer to be measured which is not affected by light diffusion of a filler and has a small absorption amount. It is an object of the present invention to provide a method for measuring the thickness of a surface layer of an electrophotographic photosensitive member capable of measuring the thickness of a layer. The surface layer of the electrophotographic photoreceptor in the present invention is such that at least a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support, and a surface layer in which a filler is dispersed is provided on the uppermost layer. The charge transport layer is provided on the charge generation layer and the surface layer is not provided as the uppermost layer. The charge transport layer corresponds to the charge transfer layer, and the protective layer corresponds to the photosensitive member having the protective layer provided on the photosensitive layer.

[0007]

In order to solve the above-mentioned problems, the present inventor has specifically measured the energy absorbed by the surface layer not as light but as a pressure wave (acoustic wave) generated due to generated heat. As a result of examining the measurement method using the light-to-heat conversion effect that can be achieved, in measuring the film thickness of the surface layer in which the filler is dispersed, the difference in the film composition of the surface layer is discriminated in advance, and the effects such as light scattering and decrease in transmittance on the surface layer are reduced. Without receiving
By applying thermal excitation light intermittently modulated at a predetermined cycle determined by the film physical property value and detecting the generated acoustic wave, it is possible to accurately measure the thickness of the surface layer in which the filler is dispersed in a laminated state. And found the present invention. That is, according to the present invention, first, in claim 1, when measuring the film thickness of the surface layer in which the filler is dispersed by using the photothermal conversion effect, the absorption coefficient of the surface layer in which the filler is dispersed is determined. There is provided a method for measuring the thickness of a surface layer of an electrophotographic photoreceptor, which comprises checking the quality of a surface layer film to be measured.

According to a second aspect of the present invention, in the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the first aspect, the thermal excitation light having an output varied on the surface of the surface layer in which the filler is dispersed. The light is intermittently incident at a predetermined period, and a proportional coefficient of the amplitude value with respect to the excitation light output is obtained by obtaining an amplitude value of the generated acoustic wave, and the presence or absence of the surface layer film quality to be measured for the film thickness is determined by the proportional coefficient. There is provided a method for measuring the film thickness of a surface layer of an electrophotographic photosensitive member, which is characterized by confirming the thickness.

Thirdly, in a third aspect of the present invention, in the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the first or second aspect, the film thermophysical property of the surface layer is dispersed on the surface of the surface layer in which the filler is dispersed. An electrophotographic method characterized by estimating the film thickness of the surface layer by detecting the amplitude value of the generated acoustic wave by injecting thermal excitation light intermittently modulated at a predetermined cycle determined from the value. A method for measuring the thickness of a photoconductor surface layer is provided.

Fourthly, according to a fourth aspect of the present invention, in the method for measuring the thickness of the electrophotographic photosensitive member surface layer according to the first or second aspect, the film thermophysical property of the surface layer is provided on the surface of the surface layer in which the filler is dispersed. The thermal excitation light intermittently modulated at a predetermined cycle determined from the value is incident, and by detecting a phase delay with respect to the modulation frequency of the generated acoustic wave, the film thickness of the surface layer is estimated. The present invention provides a method for measuring the thickness of the electrophotographic photosensitive member surface layer.

Fifthly, according to a fifth aspect of the present invention, in the method for measuring the film thickness of the surface layer of the electrophotographic photosensitive member according to any one of the first to fourth aspects, the thermal diffusivity of the surface layer in which the filler is dispersed may be reduced. There is provided a method for measuring the film thickness of the surface layer of an electrophotographic photosensitive member, wherein the thickness is 0.0013 cm ² / sec or more.

Sixthly, according to a sixth aspect, in the method for measuring the film thickness of the electrophotographic photosensitive member surface layer according to any one of the first to fifth aspects, only one kind of filler dispersed in the surface layer is used alone. A method for measuring the film thickness of the surface layer of the electrophotographic photosensitive member, characterized in that the film thickness is dispersed.

Seventhly, according to a seventh aspect, in the method for measuring the film thickness of the electrophotographic photosensitive member surface layer according to any one of the first to fifth aspects, two or more kinds of fillers dispersed in the surface layer are provided. There is provided a method for measuring the film thickness of an electrophotographic photoreceptor surface layer, wherein the thickness is mixed.

Eighthly, according to the eighth aspect, in the method for measuring a film thickness of an electrophotographic photosensitive member surface layer according to any one of the first to seventh aspects, the filler species dispersed in the surface layer is an organic filler. And a method for measuring the thickness of the electrophotographic photosensitive member surface layer.

Ninthly, according to a ninth aspect, in the method for measuring the film thickness of the electrophotographic photosensitive member surface layer according to any one of the first to seventh aspects, the filler species dispersed in the surface layer is made of an inorganic filler. And a method for measuring the thickness of the electrophotographic photosensitive member surface layer.

Tenthly, a tenth aspect of the present invention is the method for measuring the thickness of a surface layer of an electrophotographic photosensitive member according to any one of the first to ninth aspects, wherein the surface layer contains a charge transport material. There is provided a method for measuring the film thickness of a surface layer of an electrophotographic photosensitive member, which is characterized by the following.

Eleventh, Claim 11 provides the above-described Claim 1.
0. The method for measuring the film thickness of an electrophotographic photoreceptor surface layer according to item 0, wherein the wavelength of the heat excitation light source is 480 nm or more.

Twelfth, in claim 12, the above-mentioned claim 1
12. The method for measuring the film thickness of a surface layer of an electrophotographic photosensitive member according to any one of items 1 to 11, wherein the photothermal conversion effect is detected using a microphone. Is provided.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
Regarding the general detection method of the photothermal conversion (photoacoustic) signal, for example, reference materials “Edited by Shiro Sawada,“ Photoacoustic Spectroscopy and Its Applications—PAS ”, Gakkai Shuppan Center (198)
2) ", edited by Tsuguo Sawada," Photothermal Conversion Spectroscopy and Its Applications, "Gakkai Shuppan Center (1997).

As described above, according to the present invention, when the film thickness of a surface layer containing a filler is measured, light scattering due to the filler is so strong that a film which cannot be measured by a conventional optical method is subjected to photothermal conversion (photoacoustic). It uses the effect. this is,
The thermal excitation light is intermittently incident on the surface layer to be measured, and an acoustic wave generated from the filler-dispersed surface layer that has absorbed the thermal excitation light is detected. At this time, the absorption coefficient of the surface layer in which the filler is dispersed is obtained, the measurement validity of the surface layer film quality to be measured is confirmed in advance, and an error is not superimposed on the measurement result.

Note that the phase delay with respect to the amplitude or modulation frequency of the acoustic wave is proportional to the film thickness of the surface layer in which the filler is dispersed under arbitrary conditions. To obtain an amplitude signal or a phase signal and prepare a calibration curve for measurement. This makes it possible to measure the film thickness by correcting the calibration curve for the surface layer in which the filler whose film thickness is unknown is dispersed. Furthermore, in the measurement method using the photothermal conversion effect, by extracting the modulation frequency of the thermal excitation light to a specific value determined by the thermophysical property value of the surface layer, it is possible to extract only necessary thickness information in the depth direction. This makes it possible to measure the film thickness of only the surface layer in the laminated state.

Examples of the organic filler in the present invention include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, and a-carbon powder. Examples of the inorganic filler include metals such as copper, tin, aluminum and indium. Powder, tin oxide, zinc oxide, titanium oxide,
Metal oxides such as indium oxide and alumina, and inorganic materials such as potassium titanate are exemplified. The present invention is also effective for a surface layer using one of these alone or a mixture of two or more. These fillers can be dispersed in the state of the surface layer coating liquid by using an appropriate disperser.

The thermal diffusivity of the surface layer in which the filler to be measured is dispersed is 0.0 considering the dynamic range of signal extraction using the modulation frequency determined from the physical properties of the film.
It is preferably at least 013 cm ² / sec. At this time, good signal acquisition can be realized with many surface layers.

If necessary, a surface layer having a charge transporting substance added to the surface layer is also effective. Examples of the charge transporting substance include hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds. And triarylmethane compounds.

These charge transport materials are mainly 480 n
m, which absorbs light in the ultraviolet region, and causes light damage due to chemical change in the charge transport material, that is, deterioration of the donor, with respect to light in the ultraviolet region. Damage can be eliminated.

As for the use of the photothermal conversion effect, the photoacoustic method of detecting an acoustic wave by a microphone is used in a non-contact manner compared to a case where a thermoelastic wave signal in a film is obtained by a piezoelectric element or the like. A signal with a high SN ratio can be obtained. This is remarkable when the measurement target is a surface layer in which a filler is dispersed.

A part of the thermally excited light laser light incident to measure the thickness of the surface layer in which the filler is dispersed is absorbed by the surface layer. Generally, when a molecule constituting a film absorbs light energy and becomes an excited state, it returns to a ground state through various processes. In particular, those in which excitation energy is released as thermal energy to surrounding molecules through a non-emission relaxation process are to be measured for the photothermal conversion effect. Since the intensity of the excitation light is modulated at a constant frequency, heat energy is also repeatedly generated in the same cycle, and propagates in the surface layer film in the form of a heat wave. A compression wave generated by a part of the heat energy leaking into the surrounding air layer is detected as an acoustic wave using a microphone. Since the intensity of this acoustic wave has a linear relationship with the thickness of the surface layer in which the filler is dispersed, it is possible to know the thickness by measuring this intensity. In addition, since the phase delay with respect to the modulation frequency of the acoustic wave has a linear relationship with the thickness of the surface layer in which the filler is dispersed, the thickness can be known by measuring the phase delay.

In the photothermal conversion effect, since acoustic wave detection is equivalent to detecting heat transmitted to the surface, heat generated deep below the surface layer requires some time to be transmitted to the surface. Become. If an optically transparent film is present on an opaque substrate or layer where photothermal conversion occurs, there is a close relationship between the thickness of the optically transparent layer and the phase lag of the photothermal conversion signal. The phase lag Δθ and the thickness d that occur and are measured by the gas-microphone method are given by the following equations.

[0029]

(Equation 1) α: thermal diffusivity δ: mechanical phase delay of the device system As described above, the film thickness d and the phase difference Δθ have a clear linear relationship. The following formula describes the above formula. GFKirkbright, RMMiller: Analyst 107, 798 (1982) In addition, when the modulation frequency f of light is small (intermittent period is long), heat generation in a deep place also affects the surface, but when the modulation frequency f is large, only the vicinity of the surface generates light Transform (photoacoustic)
Contribute to the signal. That is, by changing the light modulation frequency f, it becomes possible to control the measurement depth of the surface layer,
Only information of an arbitrary film thickness range can be extracted. The standard of the measurement depth is generally the thermal diffusion length μ _s = (α / πf) ^1/2 , α = κ /
ρc. Here, α: thermal diffusivity, κ: thermal conductivity, ρ: density, c: specific heat. For example, in this embodiment, the photothermal conversion signal measured at the modulation frequency of the thermal excitation light: f = 750 Hz has a thermal diffusivity: α = 0.0015 cm ^2.
/ Sec, the thermal diffusion length _μs is about 8 μm, and the thermal diffusion length is 8 μm below the surface layer in the electrophotographic photosensitive member in a laminated state.
Thickness information can be measured. Also, as can be seen from the equation, the higher the thermal diffusivity of the surface layer in which the target filler is dispersed, the greater the measurement depth can be, and the easier the signal can be extracted. Considering the dynamic range of signal extraction using the modulation frequency determined from the film thermophysical property value, it is preferable that the thermal diffusivity is 0.0013 cm ² / sec or more, and at this time, good signal acquisition can be obtained with many surface layers. realizable.

In general, in order to obtain a signal dependent on the film thickness by using the photothermal conversion effect in measurement, it is necessary that the film quality of the object to be measured is uniform. May sometimes be heterogeneous. In particular, in order to obtain a signal dependent on the surface layer thickness by performing a photothermal conversion (photoacoustic) signal from the surface layer of the electrophotographic photosensitive member using the gas-microphone method, the absorption coefficient of the film quality is constant between samples. Must be This is because the photothermal conversion detection method detects physical parameters that affect the film quality and composition of the surface layer, and estimates the film thickness by correcting the calibration curve.

In the case of a solid sample, the RG theory is often used for analyzing a photothermal conversion (photoacoustic) signal, and the principle of generation and detection of a photoacoustic signal based on this is explained. "One-dimensional gas-microphone model" discussed in detail by A. Rosencwaig and A. Gersho
Details on the solution of the thermal diffusion equation in. Regarding the solution of the above-mentioned heat diffusion equation, for example, see the document "A. Rosencwaig, A. Ger.
sho, J. Appl. Phys., 47, 64 (1976) ". The important parameter here is the absorption coefficient or the reciprocal of the absorption coefficient, which is the light absorption length that gives a measure of the depth of light penetration. Generally, the absorption coefficient is peculiar to the substance, and does not change even when the film thickness changes. Since it depends on the wavelength, the photothermal conversion (photoacoustic) method enables spectral absorption spectrum measurement. Here, in order to observe the absorption of a substance as an index of the absorption coefficient, the thermal excitation light whose output is gradually changed is intermittently incident at a predetermined cycle, and the amplitude value of the generated acoustic wave is obtained. Is obtained, and the validity of the film quality to be measured is confirmed using the fact that the proportionality coefficient is an index of the amount of absorption. Heat value (light-to-heat conversion signal strength) P
Is a function of the incident light intensity I ₀ when the absorption coefficient is constant. Therefore, β is a substitute for the absorption coefficient by obtaining a proportional coefficient P / I ₀ = β. Here, it is necessary that the photothermal conversion efficiency and other constants on the surface layer serving as the transducer are constant. Further, it is more desirable that the irradiation light amount of the thermal excitation light be confirmed in advance in proportion to the light amount on the sample surface and the coefficient thereof be determined. When the light-to-heat conversion effect is used, the sample must have uniform film quality and composition because the absorption coefficient is constant, but in general, the film quality and composition may be uneven due to the liquid quality and coating. . In this case, since the absorption coefficient, which is an important parameter described above, may change, the correction value based on the calibration curve inevitably deviates from the true value. Thus, these problems can be avoided beforehand.

[0032]

Next, an example in which the present invention is applied to the measurement of the film thickness of a surface layer in which a filler of a laminated electrophotographic photosensitive member is dispersed will be described. However, the present invention is not limited by the following examples. Embodiment 1 FIG. 1 shows a configuration of a photothermal conversion signal sensing system used in the present invention. Here, the light source is composed of one type of laser using the laser 1 as a heat excitation light source, and oscillates at a wavelength in the visible region of 480 nm or more avoiding the ultraviolet region. In this embodiment, an oscillation wavelength of 532 nm LD excitation (DPSS)
A laser is used. A laser 1 used as thermal excitation light is oscillated, and the emitted light is intensity-modulated into a predetermined rectangular wave by a rotating blade type light intensity modulator 2 or an acousto-optic device (AOM). Enlarge to the desired beam diameter. A pinhole 4 is arranged at the focal position of the beam expander 3 to block high-order diffracted light components existing around the peak portion of the condensed spot, and the light intensity distribution immediately after passing through the pinhole has only the peak portion. It will remain. After that, the heat excitation light is condensed on the light guide optical fiber 6 using the condenser lens 5. Thereafter, the light is guided to the acoustic cell 7 via the optical fiber 6 and focused by the condenser lens 13 or the like onto the surface layer 12 in which the filler is dispersed. In the embodiment, the beam diameter of the thermal excitation light on the irradiation surface is φ7 μm, and the laser power is 150 mW.
It is. After the irradiation with the thermal excitation light, the filler molecules of the surface layer 12 in which the filler is dispersed absorb the thermal excitation light, and the light-to-heat conversion signal generation process, that is, the vibration of the atoms and heat due to the radiated transition, generate the thermal excitation light. When modulated as intermittent light, heating is repeated in accordance with the modulation frequency, resulting in a change in pressure of gas (air) according to the modulation frequency, generating an acoustic wave, and the microphone 14 serving as a detector.
To reach. Regarding acoustic signal detection, detection is possible if the frequency band of the intensity-modulated thermal excitation light falls within the sensitivity band of the microphone 14, and the magnitude of the sound wave depends on the modulation frequency of the excitation light and the surface layer 1 that is a transducer.
2 is uniquely determined by the amount of energy absorbed. As the microphone 14, a capacitance type microphone that measures sound pressure using a change in capacitance is generally used. In the present embodiment, Lion Corporation UC-31 is used as a capacitance type microphone. The acoustic signal detected by the microphone 14 is then transmitted to a preamplifier 15 (NFELECTRONIC INSTRUMENT).
T: LI-75A), and a two-phase lock-in amplifier 16 (NF) capable of simultaneously observing amplitude and phase delay
ELECTRONIC INSTRUMENT: 56
In 10B), only those having the same frequency as the frequency component of the modulation frequency of the thermal excitation light are extracted. An optical modulator controller 17 outputs a reference signal for homodyne measurement to the lock-in amplifier 16. Next, the output signal of the lock-in amplifier is input to the computer 19 via the A / D converter 18, and the arithmetic processing required for the film thickness measurement is performed. From this signal intensity, the thickness of the surface layer in which the filler is dispersed is determined. Further, the thickness of the surface layer in which the filler is dispersed is determined from the phase delay with respect to the signal intensity or the modulation frequency. Here, an amplitude signal and a phase signal of an acoustic signal are detected from a sample whose film thickness is known, and a calibration curve for the film thickness value is prepared. This makes it possible to estimate the thickness of the surface layer in which the filler whose thickness is unknown is dispersed, and to measure the thickness by correcting the calibration curve. However, when the thermal diffusivity is 0.0013 cm ² / sec or less, such as a surface layer in which a filler is dispersed in a polyethylene terephthalate resin or a butyral resin, the film itself becomes thermally thick and good signal acquisition is obtained. I can't. In the surface layer where TiO ₂ or SiO ₂ is dispersed in a polycarbonate resin, the thermal diffusivity is 0.00137 to 0.00.
Since the film thickness is 156 cm ² / sec, which is thermally thin with respect to the film thickness, it is possible to obtain a calibration curve in a necessary dynamic range.

FIG. 2 is a correlation diagram showing the relationship between the thickness of the surface layer in which the filler is dispersed and the amplitude value of the photothermal conversion signal. As shown in FIG. Thus, the thickness of the surface layer can be obtained through correction using a calibration curve.

FIG. 3 is a correlation diagram showing the relationship between the surface layer thickness in which the filler is dispersed and the phase delay with respect to the modulation frequency of the photothermal conversion signal. As shown in FIG. Is extracted, the film thickness can be obtained through correction using a calibration curve. Although the present embodiment shows a case where a single inorganic filler of SiO ₂ is used as the filler, the same effect can be obtained even when the filler type is changed or when two or more kinds of dispersed fillers are mixed. I can do it.

FIG. 4 shows that the thermal excitation light output is changed from 100 mW to 25.
0mW gradually change at 50mW pitch, f = 75
This is an acquisition of the amplitude value of the photothermal conversion signal generated under the condition of 0 Hz. In the figure, β indicating the slope is a proportional coefficient of the amplitude value to the pump light output, which is an index of the absorption coefficient.

FIG. 5 is a graph comparing the proportional coefficients of the respective samples obtained in FIG. The proportionality coefficient β is close to 0.002 in all the samples, and if it is at this level, the surface layer can be measured within the allowable error range of the film thickness.

FIG. 6 shows another embodiment in which the thermal excitation light output is gradually changed from 100 mW to 250 mW at a pitch of 50 mW, and the amplitude of the photothermal conversion signal generated under the condition of f = 750 Hz is measured. Has been acquired. When the proportional coefficient β in the sample is as shown in FIG. 6, the influence of the absorption coefficient of the film quality is exerted, and an error is superimposed during the correction using the calibration curve. It becomes impossible to measure the film thickness of the surface layer having a high density.

FIG. 7 is a cross-sectional view showing an example of the structure of a photoreceptor used in the present invention, in which a photosensitive layer 20 and a surface layer 12 are formed on a conductive support 8. FIG.
FIG. 4 is a cross-sectional view illustrating another configuration example, in which a photosensitive layer on a conductive support 8 is a stacked type of a charge generation layer 10 and a charge transport layer 11. 12 is a surface layer. FIG.
It is sectional drawing which shows another example of a structure, Comprising: It laminated | stacked on the electroconductive support body 8 by the type of the charge generation layer 10 and the charge transport layer 11. FIG. In this case, the charge transport layer 11 becomes a surface layer. The electrophotographic photosensitive member shown in FIG. 1 has an undercoat layer 9 between a conductive support 8 and a photosensitive layer.

[0039]

As described above, according to the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the first aspect, the absorption coefficient of the surface layer in which the filler is dispersed is determined, and the quality of the surface layer film to be measured is determined. Since the presence / absence has been confirmed in advance, when performing the film thickness measurement using the photothermal conversion effect, the surface layer can be accurately measured within an allowable error range.

According to the method for measuring the film thickness of the surface layer of the electrophotographic photosensitive member according to the second aspect, the film quality of the surface layer to be measured is proportional to the amplitude value of the acoustic wave with respect to the thermal excitation light output which is an index of the absorption coefficient. Since the proportional coefficient is an index of the absorption coefficient because the coefficient is evaluated, the presence or absence of the quality of the film to be measured can be easily confirmed, and the film quality of the surface layer sometimes becomes uneven due to instability of the manufacturing process. However, these problems can be avoided.

According to the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the third aspect, the surface of the surface layer in which the filler is dispersed is
The thermal excitation light modulated intermittently at a predetermined cycle determined from the thermophysical property value of the surface layer is incident, and the amplitude value of the generated acoustic wave is detected. The measurement of the thickness of the formed surface layer becomes possible in both the single layer and the lamination.

According to the method for measuring the thickness of the electrophotographic photosensitive member surface layer according to the fourth aspect, the amplitude value of the generated acoustic wave is replaced with
Since the phase delay of the generated acoustic wave is detected, it is possible to measure the thickness of the surface layer in which the filler is dispersed, which is difficult in the conventional method, in both the single layer and the laminated layer, as described above.

According to the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the fifth aspect, since the thermal diffusivity of the surface layer in which the filler is dispersed is 0.0013 cm ² / sec or more, the measurement depth is increased. Therefore, signals can be easily extracted, and good signal acquisition can be realized with many surface layers.

According to the method for measuring the film thickness of the surface layer of the electrophotographic photosensitive member according to the sixth aspect, since one kind of filler dispersed in the surface layer is dispersed alone, the detection by the photothermal conversion effect according to the present invention can be performed. This can be performed effectively, and the thickness measurement of the surface layer can be performed with high accuracy.

According to the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the present invention, since two or more kinds of fillers dispersed in the surface layer are mixed and dispersed, the detection by the photothermal conversion effect is also performed in this case. This can be performed effectively, and the thickness measurement of the surface layer can be performed with high accuracy.

According to the method for measuring the thickness of the surface layer of an electrophotographic photosensitive member according to the present invention, since the filler dispersed in the surface layer is an organic filler, the filler dispersed in the surface layer is detected by a photothermal conversion action. Can be performed effectively,
The thickness of the surface layer can be accurately measured.

According to the method for measuring the film thickness of the surface layer of the electrophotographic photosensitive member according to the ninth aspect, the filler dispersed in the surface layer is an inorganic filler. The detection by the action can be effectively performed, and the thickness of the surface layer can be measured accurately.

According to the method for measuring the thickness of the surface layer of an electrophotographic photosensitive member according to the tenth aspect, the present invention can be effectively carried out also in this case since the surface layer contains a charge transporting substance.

According to the method for measuring the thickness of the surface layer of the electrophotographic photosensitive member according to the present invention, the wavelength of the thermal excitation light used for measuring the thickness of the surface layer containing the charge transport material is 480 nm or more. Light damage of the transport material can be eliminated.

According to the method of measuring the thickness of the electrophotographic photosensitive member surface layer according to the twelfth aspect, since the photothermal conversion effect is detected using a microphone, a signal having a high SN ratio can be obtained in a non-contact manner. In particular, when the measurement object is a surface layer in which a filler is dispersed, the effect is remarkable.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a photothermal conversion signal sensing system used in the present invention.

FIG. 2 is a correlation diagram showing the relationship between the thickness of a surface layer in which a filler is dispersed and the amplitude value of a photothermal conversion signal.

FIG. 3 is a correlation diagram showing the relationship between the thickness of a surface layer in which a filler is dispersed and the phase delay with respect to the modulation frequency of a photothermal conversion signal.

FIG. 4 is a diagram showing a proportional coefficient β of a photothermal conversion signal amplitude value to a thermal excitation light output.

FIG. 5 is a graph comparing the proportional coefficient β of each sample obtained in FIG. 4;

FIG. 6 is a diagram showing a proportional coefficient β according to another embodiment.

FIG. 7 is a cross-sectional view illustrating a configuration example of a photoconductor.

FIG. 8 is a sectional view showing another configuration example of the photoconductor.

FIG. 9 is a cross-sectional view showing still another configuration example of the photoconductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal excitation light source (laser) 2 Light intensity modulator 3 Beam expander 4 Pinhole 5 Condensing lens 6 Optical fiber 7 Acoustic cell 8 Conductive support 9 Undercoat layer 10 Charge generation layer 11 Charge transport layer 12 Surface layer 13 Capacitor Lens 14 Microphone 17 Optical modulator controller 19 Computer 20 Photosensitive layer

Claims (12)

[Claims] When measuring the film thickness of a surface layer in which a filler is dispersed using a photothermal conversion effect, an absorption coefficient of the surface layer in which a filler is dispersed is determined, and the presence or absence of a surface layer film quality to be subjected to film thickness measurement is determined. A method for measuring the thickness of a surface layer of an electrophotographic photoreceptor, characterized by confirming. 2. The method for measuring the thickness of a surface layer of an electrophotographic photosensitive member according to claim 1, wherein the thermal excitation light whose output is changed is intermittently incident on the surface of the surface layer in which the filler is dispersed at a predetermined cycle. And calculating the amplitude value of the generated acoustic wave to obtain a proportional coefficient of the amplitude value with respect to the excitation light output, and confirming the presence or absence of the surface layer film quality to be measured for the film thickness by the proportional coefficient. A method for measuring the thickness of the photoreceptor surface layer. 3. The method for measuring the film thickness of an electrophotographic photoreceptor surface layer according to claim 1, wherein the surface of the surface layer in which the filler is dispersed has a predetermined period determined by a thermophysical property value of the surface layer. A method for measuring the thickness of a surface layer of an electrophotographic photoreceptor, comprising estimating the thickness of the surface layer by detecting the amplitude value of the generated acoustic wave by applying intermittently modulated thermal excitation light. . 4. The method for measuring the thickness of a surface layer of an electrophotographic photoreceptor according to claim 1, wherein the surface of the surface layer in which the filler is dispersed has a predetermined period determined by a thermophysical property value of the surface layer. Film thickness of the electrophotographic photoreceptor surface layer, characterized by estimating the film thickness of the surface layer by injecting intermittently modulated thermal excitation light and detecting a phase delay with respect to the modulation frequency of the generated acoustic wave. Thickness measurement method. 5. The method for measuring the film thickness of an electrophotographic photoreceptor surface layer according to claim 1, wherein the thermal diffusivity of the surface layer in which the filler is dispersed is 0.0013 cm ² / s.
ec or more, wherein the thickness of the electrophotographic photosensitive member surface layer is measured. 6. The method for measuring the film thickness of an electrophotographic photosensitive member surface layer according to claim 1, wherein one kind of filler dispersed in the surface layer is dispersed alone. The method for measuring the thickness of the electrophotographic photosensitive member surface layer. 7. The method for measuring the thickness of an electrophotographic photosensitive member surface layer according to claim 1, wherein two or more fillers dispersed in the surface layer are mixed. Method for measuring the thickness of the electrophotographic photosensitive member surface layer. 8. The method for measuring the film thickness of a surface layer of an electrophotographic photosensitive member according to claim 1, wherein the filler species dispersed in the surface layer is an organic filler. A method for measuring the thickness of the photoreceptor surface layer. 9. The method for measuring the film thickness of an electrophotographic photosensitive member surface layer according to claim 1, wherein the filler species dispersed in the surface layer is an inorganic filler. A method for measuring the thickness of the photoreceptor surface layer. 10. The electrophotographic photosensitive member surface measuring method according to claim 1, wherein said surface layer contains a charge transporting material. Method for measuring layer thickness. 11. The method according to claim 10, wherein the wavelength of the heat excitation light source is 480.
A method for measuring the thickness of a surface layer of an electrophotographic photosensitive member, wherein the thickness is not less than nm. 12. The electrophotographic photosensitive member according to claim 1, wherein the photothermal conversion effect is detected by using a microphone. A method for measuring the thickness of a body surface layer.