JPH01152305A - Thickness measurement for photosensitive layer - Google Patents

Abstract

PURPOSE:To achieve a non-contact measurement of the thickness of a photosensitive layer, by measuring distances between a reference surface and a conductive substrate and the surface of a photosensitive layer by electric and optical method to determine the difference between the results. CONSTITUTION:Light from a projector section 31 is emitted onto the surface 21 of a photosensitive layer 2 and received with a light receiving section 32 to calculate a distance to the surface 21 thereof 2 from a reference surface 5 according to the current angle of incidence. On the other hand, an eddy current is generated in a photosensitive substrate 1 by an alternating magnetic field generated with an electromagnetic sensor 4 to calculate a distance between the reference surface 5 and the surface 11 of the substrate 1 from a value of a magnetic field fed back to the sensor. The difference between the two distances is computed to determine the thickness of the photosensitive layer 2. This enables non-contact measurement of the thickness of the photosensitive layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for measuring the thickness of a photosensitive layer provided on a conductive substrate of an electrophotographic photoreceptor.

[Conventional technology]

The photosensitive layer provided on the substrate of an electrophotographic photoreceptor is a layer of photoconductive material and may optionally include a layer of insulating material. To measure the thickness of this photosensitive layer, a measurement probe is brought into contact with the surface of the photoreceptor, taking advantage of its higher resistivity than the conductive substrate, and an alternating magnetic field generates eddy currents in the substrate. An eddy current method was used, which utilizes changes in eddy currents that correspond to changes in distance between the two.

[Problem that the invention seeks to solve]

However, in the case of this type of eddy current thickness measurement method,
Since the measurement probe is brought into contact with the surface of the photoreceptor, there is a risk of causing a direct defect on the surface of the photoreceptor or a latent defect inside the photoreceptor.

An object of the present invention is to provide a method for measuring the thickness of a photosensitive layer that can be carried out without contacting the surface of a photoreceptor.

[Means for solving problems]

In order to achieve the above object, the method of the present invention electrically measures the distance from a reference surface distant from the photoreceptor surface to a conductive substrate, and optically measures the distance from the reference surface to the photoreceptor surface. Measure the distance and calculate the difference between the two distances.

[Effect]

By measuring a reference surface that is far from the photoreceptor surface, the distance from that surface to the conductive substrate surface can be measured without contacting the photoreceptor surface using an eddy current method or a capacitance method, and the distance from the reference surface to the photoreceptor surface can be measured using an eddy current method or a capacitance method. Since it is also possible to measure without contacting the photoreceptor surface using the optical method, by calculating the thickness of the photoreceptor layer from the difference between the two distances, the thickness of the photoreceptor layer can be measured without contacting the photoreceptor surface.

〔Example〕

In one embodiment shown in FIG. 1, two displacement meters with different detection functions are installed at certain positions on a photoreceptor, which has a photoreceptor layer 2 consisting of a single layer or multiple layers in the case of a functionally separated type, on a conductive substrate 1. is located. One of the displacement meters uses an optical sensor to reflect light emitted from a light projecting section 31 on the surface 21 of the photosensitive layer 2, and receives the light at a light receiving section 32, and determines the distance to the photosensitive layer surface 21 according to the incident angle at that time. Distance X from reference plane 5
, to detect. The other displacement meter is an electromagnetic sensor 4,
An eddy current is generated in the photoreceptor substrate 1 by the alternating magnetic field generated by the oscillator, and the amount of the magnetic field returned to the sensor 4 is detected by the search coil, and the amount of the magnetic field is detected from the reference surface 5 to the substrate 1 and the photoreceptor layer 2.
The distance X to the interface 11 is detected. These two ([
The difference between Xa l XD, ie (xl-X,) is the thickness of the photosensitive layer 2.

FIG. 2 shows another embodiment in which a light transmission amount detection type is used as an optical displacement meter, which is effective for a circular photoreceptor base for which an M cylinder is normally used. That is, part of the light beam 6 emitted from the light projecting section 61 is blocked by the photosensitive layer 2, and the rest reaches the light receiving section 62, which is arranged together with the light projecting section 61 on the same plane parallel to the reference plane. The distance from the reference surface 5 to the photosensitive layer surface 21 is 1! lxp is detected, and the thickness of the photosensitive layer 2 is determined in the same manner as described above.

As the electrical displacement meter, one that utilizes changes in capacitance can also be used. However, in the case of electromagnetic sensors as well, there is no effect on the measured values of the photosensitive layer made of a photoconductive substance existing on the conductive substrate.
If calibration is performed in advance using an appropriate method, changes in the measured value due to changes in the thickness of the photosensitive layer can be almost ignored, so the accuracy of the obtained thickness value of the photosensitive layer 2 is high.

〔Effect of the invention〕

According to the present invention, the photoreceptor substrate is electrically
For the photoconductor surface, the distance from the reference plane that is far from the photoconductor is detected using an optical method, and the thickness of the photoconductor layer is calculated from the difference. Measurement becomes possible, and the photoreceptor can be protected from defects caused by contact during measurement.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing another embodiment. 1: Conductive substrate, 2: Photosensitive layer, 31.61: Light projecting section, 3
2.62: Light receiving section, 4: Electromagnetic sensor, 5: Reference surface. 7.・′− 7. Endurance, ヮ+, ヮtake 1,. Figure 1 Figure 2

Claims (1)

[Claims] 1) Electrically measuring the distance from a reference surface that is distant from the photoreceptor surface to the conductive substrate, optically measuring the distance from the reference surface to the photoreceptor surface, and calculating the difference between the two distances. Characteristic photosensitive layer thickness measurement method.