JPH02201143A - Abnormality detector for coating material surface - Google Patents

Abstract

PURPOSE:To surely and accurately detect the abnormality of the surface of a coating material by irradiating the surface at a prescribed angle and detecting the optical information of the reflected light thereof. CONSTITUTION:The laser light from a light source 11 is projected via a rotary polyhedral mirror 13 and a parabolic mirror 14 to the surface of a photosensitive drum 30 at a prescribed angle with the axial center direction and scans the surface. The reflected light on the surface thereof is sent to a photodetector 17 and the intensity of the light is detected by a photoelectron multiplier 17b and is transmitted to a surface device, etc. The abnormality on the drum 30 surface is inspected by the repetition of such operation over the entire surface.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a coating in which a coating layer is provided on a substrate, such as a photoreceptor used in an image forming apparatus such as a copying machine or a laser printer. The present invention relates to a device for detecting an abnormality on the surface of an object.

(Prior Art) Photoreceptor drums used in image forming devices such as copying machines and laser printers are usually made by directly attaching them to aluminum tubes.
Alternatively, a photosensitive layer is coated with an alumite layer interposed therebetween. Such a photoreceptor drum cannot form a good image if its surface (the surface of the photoreceptor layer) is scratched or has foreign matter such as dust attached. An inspection is performed to determine whether there are any abnormalities such as scratches or adhesion of foreign matter on the surface of the layer.

Conventionally, for inspection of the surface of a photoreceptor drum, for example,
The device disclosed in Publication No. 1-20080 is used. This device irradiates the surface of the photoreceptor drum with light and detects abnormalities on the surface of the photoreceptor drum based on the amount and intensity of the reflected light. Recently, coherent laser light has been used in such photoreceptor drum surface inspection devices to improve inspection accuracy and inspection speed.

An example of an abnormality detection device on the surface of a photoreceptor drum using laser light is shown in FIG.
is rotatably supported, and on the photosensitive drum 30,
Laser light emitted from a laser light source 41 is irradiated onto a rotating polygon mirror 44 via a pair of reflections M42 and M43. The rotating polygon mirror 44 sequentially scans the irradiated laser light from one end to the other end along the axial direction of the photoreceptor drum 30 by its rotation. The laser beam irradiated in the direction of the photoreceptor drum 30 is sequentially reflected on the surface of the photoreceptor drum 30 and applied to the photomultiplier tube 45a in the light receiving section 45. A photomultiplier tube 45a in the light receiving section 45 sequentially captures the laser light reflected on the surface of the photoreceptor drum 30, and sequentially outputs voltages corresponding to the intensity of the laser light. Photosensitive drum 30
If there is an abnormality such as a scratch on the surface, the laser light irradiated to the abnormal part is diffusely reflected, and the intensity of the laser light captured by the photomultiplier tube 45a is reduced. Therefore, the detection voltage of the photomultiplier tube 45a decreases, and based on the detection result, an abnormality on the surface of the photoreceptor drum 30 is detected. When scanning in one direction along the axial direction of the photoreceptor drum 30 is completed, the photoreceptor drum 30 is rotated by a predetermined amount, and
The laser beam is applied to the surface area of the photoreceptor drum 30 adjacent to the area where the laser beam scan ended immediately before.
Scanned along the 0 axis direction. Thereafter, similar operations are repeated, and the entire surface of the photoreceptor drum 30 is inspected to see if there is any abnormality.

(Issues to be Solved by the Invention 11) As mentioned above, the photosensitive drum 30 has a photosensitive layer laminated directly on the outer circumferential surface of an aluminum tube or via an aluminium layer. When laser light is irradiated onto the photosensitive drum 30 on which the photosensitive layer has been deposited, part of the laser light is reflected at the interface of the photosensitive layer and also enters the photosensitive layer. When the laser light that has entered the photosensitive layer is diffusely reflected within the photosensitive layer, the amount of laser light that passes through the photosensitive layer is small, and the laser beam is reflected at the interface between the photosensitive layer and the aluminum tube. As the amount of light decreases, the laser light reflected from the surface of the photosensitive layer at the interface has almost no effect. The amount of laser light reflected at the interface increases, and the amount of laser light emitted from the photosensitive layer increases. The laser beam reflected by the rotating polygon j144 is directly scanned to the photosensitive layer of the photosensitive drum 30 in the axial direction of the photosensitive drum 30, and the laser beam reflected from the photosensitive layer is reflected. The angle changes sequentially while the laser beam is scanned along the axial direction of the photoreceptor drum 3°.

For this reason, the phase of the laser beam reflected by the photosensitive layer and the laser beam reflected at the interface between the photosensitive layer and the aluminum tube described above and emitted from the photosensitive layer is shifted, causing interference between the two. , this phase difference is caused by the scanning of the laser beam,
The interference occurs sequentially along the axial direction of the photoreceptor drum 30, and so-called interference fringes with bright and clear patterns are generated on the photoreceptor drum 30. A photomultiplier tube 45a disposed within the light receiving section 45
captures the interference light and outputs a voltage corresponding to the intensity of the interference light, so the detection signal of the photomultiplier tube 45 is
In such a state where the interference fringes are superimposed as noise on the intensity detection signal of the laser beam, there is a possibility that an abnormality on the surface of the photoreceptor drum 30 cannot be detected.

The present invention solves the above-mentioned conventional problems, and its purpose is to provide an abnormality detection device on the surface of a coated object that can reliably and accurately detect abnormalities on the surface of the coated object using laser light. be.

(Means for Solving the Problems) The abnormality detection device for a coated object of the present invention detects an abnormality on the surface of the coated object by irradiating a laser beam onto the surface of the coated object, which has a coating layer provided on a substrate. The apparatus includes a laser light source, a scanning means for sequentially scanning laser light emitted from the laser light source in a predetermined direction, and a laser light scanned by the scanning means to the surface of the coated object. means for changing the optical path of the laser beam so that it is always irradiated sequentially at a predetermined angle; and a detection means for capturing the reflected light of the laser beam irradiated on the surface of the coated object and detecting its optical information. By this, the above object is achieved.

(Example) The present invention will be described below with reference to Examples.

FIG. 1 is a schematic diagram of an apparatus for detecting an abnormality on the surface of a coated object according to the present invention. The detection device is used, for example, to detect an abnormality on the surface of a photosensitive drum 30 used in an image forming apparatus such as a copying machine. The photosensitive drum 30
In this case, a photosensitive layer is directly laminated on the outer peripheral surface of an aluminum tube.

The photosensitive drum 30, which is the object to be inspected, is placed on the horizontal stage 16. The stage 16 is attached to the output shaft of a stepping motor 15 disposed below the stage 16, and the stepping motor 15 is driven to rotate the stage 16 intermittently.

A laser light source 11 that emits He-Ne laser light is installed on the side of the photosensitive drum 30 placed on the stage 16.
is installed. The laser beam emitted from the laser beam 111 is condensed by a condenser lens 12 and irradiated onto a rotating polygon mirror 13 which is a laser beam scanning means. The rotation axis of the rotating polygon mirror 13 is perpendicular to the irradiated laser beam, and by its rotation, the laser beam emitted from the laser light source and condensed by the condensing lens 12 is
The light is sequentially irradiated onto a parabolic mirror 14 serving as an optical path changing means. The paraboloid j! Reference numeral 14 has a parabolic inner peripheral surface facing the photosensitive drum 30 placed on the stage 16 and the rotating polygon mirror 13 . The paraboloid jJ! The inner circumferential surface 14 is a section along the axial direction of the photosensitive drum 30 placed on the stage 16.

The inner peripheral surface of the surface is parabolic, and the parabolic surface j
A1.1 is sequentially scanned with laser light along the axial direction of the photoreceptor drum 31) by the rotating polygon jm1.3. The shape of the parabola is determined when the laser beam sequentially scanned in the axial direction of the photoreceptor drum 30 by the rotating polygon mirror 13 is reflected by the inner peripheral surface (paraboloid) of the parabolic mirror 14. In addition, it is set so that the surface of the photoreceptor drum 30 is always irradiated sequentially at a predetermined angle. Therefore, the laser beam scanned in a predetermined direction by the rotating polygon mirror 13 is transmitted to the photoreceptor drum 3 mounted on the stage 16 by the parabolic mirror 14.
0 surface is irradiated sequentially at a predetermined angle,
Scanning is performed along the axial direction of the photosensitive drum 30.

The laser beam scanned along the axial direction of the surface of the photoreceptor drum 30 is reflected by the surface of the photoreceptor drum 30 at a predetermined reflection angle, and is irradiated onto the light receiver 17 .

The light receiving surface of the light receiver 17 is parallel to the direction of the photoreceptor drum 31), and a light receiving window is provided on the light receiving surface. The length of the light-receiving window is slightly longer than the length of the photoreceptor drum 31 in the axial direction, and a diffuser plate 17a made of, for example, ground glass is attached to the light-receiving window. The laser beam reflected by the photoreceptor drum 30 is transmitted to the diffuser plate 17.
The light enters the interior of the light receiving unit 317 through the y. The light receiver 17
Inside, there is a photomultiplier tube 1? for detecting optical information of the laser beam reflected from the photoreceptor drum 30. b is provided. The laser beam reflected by the photoreceptor drum 30 is diffused by the diffusion plate 17λ and enters the photomultiplier tube 17b. The photomultiplier tube 17b outputs a voltage corresponding to the intensity of the incident laser light.

The diffuser plate 17λ eliminates unevenness in the amount of laser light that passes through the diffuser plate 17a and enters the photomultiplier tube 17b.

In the inspection device for the surface of a coated object with such a configuration,
The laser beam emitted from the laser light source 11 is irradiated onto the rotating polygon 113 through the condensing lens 12. The 9-rotating polygon jlJ113 directs the laser beam irradiated by its rotation along the paraboloid of the parabolic mirror 14. Scan sequentially. The laser beam irradiated onto the parabolic mirror 14 is sequentially reflected by the parabolic surface of the parabolic surface 1114, and
The light is irradiated onto the surface of the photoreceptor drum 30 placed at a predetermined angle with respect to the surface of the photoreceptor drum 30 . As a result, the laser beam is incident on the surface of the photoreceptor drum 30 at a predetermined angle, and is sequentially scanned along the axial direction of the photoreceptor drum 30. The laser beam irradiated onto the photoreceptor drum 30 is reflected by the surface of the photoreceptor drum 2.
7 is irradiated fourthly. Receiver! After passing through the diffuser plate 171 of the light receiver 17, the laser beam irradiated onto the light receiver 17 passes through the photomultiplier tube 1, which is an optical information detecting means in the light receiver 17.
given to 7b. The photomultiplier tube 17b sequentially detects the intensity of the incident laser light and outputs a voltage corresponding to the intensity of the laser light. The detection results are output to a predetermined display device, storage device, or the like.

When the laser beam is scanned from one end to the other along the axis of the photoreceptor drum 30, the stepping motor 15 is driven and the stage 16 is rotated by a predetermined amount. The position of the laser beam irradiated onto the surface of the photoreceptor drum 30 on the photoreceptor drum 16 is a portion adjacent to the position of the laser beam scanned in the direct H direction. Then, a laser beam is scanned on the surface of the photoreceptor drum 3o,
The scanned laser light is sequentially incident on the photomultiplier tube 17b of the light receiver 17. By sequentially repeating such operations, the entire surface of the photoreceptor drum 30 is scanned with laser light, and abnormalities are inspected over the entire surface.

As described above, the laser light irradiated onto the photoreceptor drum 30 is always incident on the surface of the photoreceptor drum 30 at a predetermined angle and scanned in the direction of its axis. Even if the laser light reflected at the interface between the photosensitive layer and the aluminum tube is emitted from the photosensitive layer, at the time of emission, the laser light is irradiated onto the photosensitive layer and directly reflected by the photosensitive layer. The phase with photoreceptor drum 3 is
It becomes constant in the minute direction of 0. As a result, the interference laser beam reflected by the photoreceptor drum 3 (1) enters the photomultiplier tube 17b in the light receiver 17, but the photomultiplier tube 17h The intensity is detected with no noise superimposed. If there is an abnormality on the surface of the photoreceptor drum 30, the laser light is diffusely reflected at the abnormality and is therefore incident on the photomultiplier tube 17b. The intensity of the laser beam decreases, and the output voltage of the photomultiplier tube 17b decreases.Therefore, when the output voltage of the photomultiplier tube 17b decreases below a predetermined value, the photoreceptor drum 3
It is determined that an abnormality exists on the surface of the photosensitive drum 30, and based on the detection result, scratches, adhesion of foreign matter, etc. on the surface of the photosensitive drum 30 can be found very easily.

FIG. 2 shows a device for detecting abnormalities on the surface of a coated object in another embodiment of the present invention. General information! FIG.

In this embodiment, a laser beam emitted from a laser light source 11 is irradiated onto a rotating polygon j113, which is a laser beam scanning means, via a condenser lens 12 and a reflecting mirror 10. The rotating polygon mirror 13 is arranged so that its reflected light is irradiated in the direction in which the photoreceptor drum 30 is arranged. A concave lens 19 is interposed. The one-turn polygon 3113 is positioned so as to reflect the laser beam at the focal position of the concave lens 19. Therefore,
The laser beam scanned by the rotating polygon 13 passes through the concave lens 19 and is sequentially irradiated onto the surface of the photoreceptor drum 30 at a predetermined angle. Scanned towards the heart. Photosensitive drum 3
The laser beam reflected at 0 is similar to the above example,
The laser beam enters the photomultiplier 11'4 tube 17b, which is an optical information detection means, through the diffuser plate 17& of the light receiver 17, and the intensity of the laser beam is sequentially increased by the photomultiplier tube 17b.
Detected.

In the case of this embodiment, as in the actual M1 example, the surface of the photoreceptor drum 30 is always irradiated with laser light at four predetermined angles, so that the photoreceptor layer and the aluminum tube on the photoreceptor drum 30 are Even if the laser reflected light at the interface and the laser reflected light at the surface of the photosensitive layer interfere with each other, the photomultiplier tube 17b receives laser light whose phase difference is constant in the axial direction of the photosensitive drum 30. is incident. As a result, the photomultiplier tube 17b detects the intensity of the laser beam and noise without being superimposed, and therefore can easily detect abnormalities such as scratches or adhesion of foreign matter on the surface of the photoreceptor drum 30.

(Effects of the Invention) The apparatus for detecting an abnormality on the surface of a coated object of the present invention is configured such that the laser beam is directed onto the surface of the coated object to be inspected using an optical path changing means such as a parabolic mirror or a concave lens. Since the laser beam is always irradiated at a predetermined angle, the phase difference between the laser beam directly reflected on the surface of the coated object and the laser beam reflected at the interface of the coating layer is constant regardless of the scanning of the laser beam. Therefore, noise is not superimposed on the detection signal by the optical information detection means, and abnormalities on the surface of the coated object can be detected reliably and accurately.

,''t; Day FIG. 1 is a schematic configuration diagram showing an example of the apparatus for detecting an abnormality on the surface of a coated object according to the present invention, and FIG. 2 is a schematic configuration diagram of another embodiment of the apparatus for detecting an abnormality on the surface of a coated object according to the present invention. Figure, 3rd
The figure is a schematic configuration diagram of a conventional abnormality detection device on the surface of a coated object.

11... Laser light source, 13... Rotating polygon mirror, 14
...parabolic mirror, 15...stepping motor, 1
6... Stage, 17... Light receiver, 19... Concave lens.

that's all

Claims (1)

[Claims] 1. An apparatus for detecting abnormalities on the surface of a coated article by irradiating the surface of a coated article with a coating layer on a substrate, comprising: a laser light source; and the laser light source. scanning means for sequentially scanning laser light emitted from the surface in a predetermined direction; An abnormality detection device on the surface of a coated object, comprising: an optical path changing means for changing the optical path of the laser beam; and a detection means for capturing the reflected light of the laser beam irradiated on the surface of the coated object and detecting its optical information. .