JPH0518728A - Surface inspection apparatus - Google Patents

Abstract

PURPOSE:To project a constant pattern to the surface of an inspection object and detect the strain of the pattern. CONSTITUTION:An inspection object 1 such as a photosensitive seamless belt, etc., is supported by cylindrical bodies 2, 3 and the cylindrical body 3 is driven and rotated by a driving apparatus 4 and a belt 5 to transmit the motive power to drive the inspection object 1. The picture picking-up region of the surface of the inspection object 1 is uniformly illuminated by an illuminating apparatus 9 composed of a light source 6, a light radiating lens 7, and a diffusion plate 8 and photographed by a picture picking-up device 11 such as a picture picking-up lens 10, CCD, etc. To project a constant pattern to the picture picking-up region of the surface of the inspection object, a projector apparatus 15 composed of a light source 12, a slide 13 the pattern is saved thereon, and a projector lens 14 is provided. A brightness distribution of the lattice pattern is projected to the surface of the inspection object by the projector apparatus and the deformation of the surface of the inspection object is detected by the deformation of the pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection device, and more particularly, to a surface inspection device for a photoconductor such as a copying machine or a printer using an electrophotographic method. For example, it is applied to a surface inspection device for a seamless belt photoreceptor.

[0002]

2. Description of the Related Art In an electrostatic copying machine generally used in the past, a photosensitive drum having a cylindrical outer peripheral surface covered with a photosensitive layer is rotatably mounted at a substantially central portion of a copying machine body. If the surface of the photosensitive layer coated on the peripheral surface of this photosensitive drum is scratched, it becomes difficult to form a latent image on the photosensitive layer, or toner does not smoothly adhere to the copy paper and is used for image formation. It will cause trouble. Therefore, when setting the manufactured photosensitive drum in the copying machine, it is necessary to inspect the photosensitive drum to remove defective products.

Regarding the surface inspection of the photosensitive drum of a copying machine, for example, Japanese Patent Laid-Open No. 62-52408 proposes "Method and apparatus for inspecting photosensitive drum for copying machine". In this publication, an optical flat is made to face a photosensitive layer coated on the outer peripheral surface of a photosensitive drum of a copying machine on which a latent image is formed, with a slight gap between the optical flat and the photosensitive layer. A defective product of the photosensitive drum is inspected by irradiating the optical flat with light and visually observing interference fringes generated on the optical flat. That is, an optical flat is used to observe interference fringes with the photoconductor drum to perform surface inspection.

The "surface image inspection device" proposed in Japanese Patent Laid-Open No. 1-21883 irradiates a laser beam so that the surface of the object to be inspected is linearly scanned, and the reflected light or transmitted light thereof The change is detected to inspect the surface damage of the inspection object. That is, in the surface flaw inspection on the side surface of the cylindrical body by laser irradiation, the state of the surface of the inspection object is detected by detecting the intensity change of scattered light or reflected light. Further, the "surface defect inspection apparatus" proposed in Japanese Patent Application Laid-Open No. 1-284742 uses a reflection type optical fiber sensor integrally provided with a light projecting fiber and a light receiving fiber,
This is to optically detect a defective portion formed on the surface of the inspection object. That is, the light projecting fiber and the light receiving fiber are integrated, and surface defects such as irregularities are detected from changes in the intensity of reflected light.

A photoreceptor used in an electrophotographic copying machine, a printer using the principle of electrophotography, or the like, has a defect such as a scratch or uneven coating on the surface thereof, which deteriorates image quality.
Therefore, it is necessary to inspect the surface of the photoconductor for defects before incorporating it into a copying machine or the like. Currently, in most cases, the surface of the photoconductor is visually inspected for defects. However, in order to automate the inspection, in the case of a photoconductor drum or the like, the drum is rotated and driven in a one-dimensional manner. There has been proposed a method of detecting a defect by capturing an image with a sensor array and processing the captured image of the drum surface.

[0006] Recently, along with the photoconductor drums having an aluminum drum as a base, the production of photoconductors having a nickel belt as a base has become popular. Along with this, defects due to the deformation of the substrate, which did not occur on the photosensitive drum, are occurring. Such a defect may not be observable as a clear change in brightness on an image of the surface, and it is difficult to detect such a defect by image processing relying only on the change in brightness.

[0007]

[Object] The present invention has been made in view of the above circumstances, and in order to detect defects due to deformation of a substrate, a certain pattern is projected on the surface of an object to be inspected, and a deformed portion of the substrate is detected. The purpose of the present invention is to provide a surface inspection device for detecting pattern distortion.

[0008]

In order to achieve the above object, the present invention provides (1)
Supporting means for supporting a belt-shaped object which is an object to be inspected, driving means for rotationally driving the supporting means, illuminating means for illuminating the surface of the object to be inspected driven by the driving means, Projecting means for projecting a certain pattern on an imaging area of the surface; imaging means for imaging the imaging area of the surface of the inspection object illuminated by the illumination means; and imaging means for imaging the pattern projected on the imaging area, Image processing means for processing a picked-up image obtained by the image pickup means to detect defects on the surface of the object to be inspected, and (2) the pattern projected by the projection means is a lattice pattern. Further, (3) the pattern projected by the projection means is projection by infrared rays, or (4)
Supporting means for supporting a belt-like object which is an object to be inspected, driving means for rotationally driving the supporting means, illuminating means for illuminating the surface of the object to be inspected driven by the driving means, and the object to be inspected. Projecting means for projecting a certain pattern on an imaging area of the surface; imaging means for imaging the imaging area of the surface of the inspection object illuminated by the illumination means; and imaging means for imaging the pattern projected on the imaging area, Image processing means for processing a captured image obtained by the image capturing means to detect defects on the surface of the object to be inspected, wherein the image capturing means captures only visible light and only infrared rays. And an image pickup means. Hereinafter, description will be given based on examples of the present invention.

FIG. 1 is a block diagram for explaining an embodiment (claim 1) of a surface inspection apparatus according to the present invention.
Is a photosensitive member seamless belt (inspection object), 2, 3 is a cylindrical body, 4 is a driving device, 5 is a transmission belt, 6 is a light source, 7 is a light projecting lens, 8 is a diffusing plate, 9 is an illuminating device, 10 is An imaging lens, 11 is an imaging device, 12 is a light source, 13 is a slide, 14 is a projector lens, and 15 is a projection device.

Inspected object 1 such as a photosensitive member seamless belt
Are supported by cylindrical bodies 2 and 3, and the cylindrical body 3 is rotationally driven by a drive device 4 and a belt 5 that transmits power to drive the device under test 1. The imaging area on the surface of the object to be inspected is uniformly illuminated by an illumination device 9 including a light source 6, a light projecting lens 7, and a diffusion plate 8, and is imaged by an imaging device 10 such as an imaging lens 10 and a CCD (charge coupled device). . An image processing device or the like performs defect detection processing on the captured image data. Further, in order to project a certain pattern on the imaging area on the surface of the inspection object 1, a projection device 15 including a light source 12, a slide 13 on which the pattern is recorded, and a projector lens 14 is provided. When the conventional inspection is performed, the surface of the inspection object 1 may be imaged without projecting the pattern. On the other hand, when detecting the deformation of the surface of the inspection object that is difficult to detect by the conventional method, the projection device 15 projects, for example, the luminance distribution of the lattice pattern onto the surface of the inspection object 1, and the deformation of the pattern is projected. From this, it is possible to detect the deformation of the surface of the device under test 1 (claim 2).

2A and 2B are views showing a grid pattern and a picked-up image, FIG. 2A shows a projected grid pattern, and FIG. 2B shows a picked-up image. If the surface of the inspection object is imaged when there is no deformation on the surface of the inspection object,
Although the same pattern as that in FIG. 10A is obtained, when the surface of the object to be inspected is deformed, a distorted pattern is seen at the position A shown by the dotted line in the imaging region as shown in FIG. To be By detecting the distortion of this pattern, it is possible to easily detect the deformation defect on the surface of the inspection object.

FIG. 3 is a flow chart for explaining a process for detecting a deformation defect on the surface of the object to be inspected. Hereinafter, each step will be described in order. step1 : First, the illumination device uniformly illuminates the imaging region on the surface of the inspection object, and the image from the imaging region is input via the imaging device. step2 : Next, the projection device projects a fixed pattern onto the imaging area, and pattern matching is performed with the image input in step1. step3 : Check for deformation defects. step4: In the step3, and exit rejected if any deformation defects. step5 : In step 3, if there is no deformation defect, the belt as the inspection object is driven. step6 : It is checked whether the belt, which is the object to be inspected, makes one round. If it has completed one round, it ends;
Return to step 1.

A lattice pattern is the most effective pattern for detecting deformation defects on the surface of the object to be inspected, but the distance between the lattices should be an optimum distance depending on the size of the defect generated on the surface of the object to be inspected. If set, the defect can be detected with higher accuracy. Further, by using a light source that emits infrared rays as the light source of the projection device in FIG. 1, pattern projection by infrared rays can be easily realized (claim 3).
As the light source, an LED (light emitting diode), an LD (laser diode), or the like can be considered. By performing pattern projection by infrared rays, it is possible to easily separate from visible light by a filter or the like, so that the conventional defect inspection method and the method for detecting deformation defects on the surface of the inspection object according to the present invention are simultaneously performed. It becomes possible.

FIG. 4 is a diagram showing another embodiment (Claim 4) of the surface inspection apparatus according to the present invention, which is provided with an image pickup means for picking up only visible light and an image pickup means for picking up only infrared rays. . In the figure, 16 is a dichroic mirror, 17 is an image pickup lens, 18 is an image pickup device, and other parts having the same operations as in FIG. Although the illumination device, the projection device, and the driving device are omitted in FIG. 4, they are the same as those in FIG.

A first image pickup device including an image pickup lens 10 and an image pickup device 11 for picking up visible light, and a second image pickup device including an image pickup lens 17 and an image pickup device 18 for picking up a projected pattern of infrared rays are provided, The light reflected on the surface of the body transmits visible light, and the infrared light is separated by the reflecting dichroic mirror 16. By performing the defect detection processing on the images obtained by the respective image pickup devices, the conventional defect inspection and the deformation defect inspection of the surface of the inspection object according to the present invention can be performed at the same time.

[0016]

As is apparent from the above description, the present invention has the following effects. (1) Effect on Claim 1: Since the projection device for projecting a constant pattern is provided on the imaging portion, the deformation of the surface of the inspection object can be detected by detecting the distortion of the projected pattern. . (2) Effect on Claim 2: Since the projection pattern is a lattice pattern, the distortion of the pattern due to the deformation of the surface of the inspection object can be detected with high sensitivity. (3) Effect on Claim 3: Since the projection pattern is of infrared rays, the deformation of the surface of the object to be inspected is detected without disturbing the conventional inspection method for detecting the change in brightness of the surface of the object to be inspected by visible light. be able to. Also, since it is infrared, it does not damage the photoconductor unlike ultraviolet. (4) Effect on Claim 4: An inspection method for detecting a change in the brightness of the surface of the object to be inspected, since the image pickup means for picking up visible light and the image pickup means for picking up infrared rays are provided.
The inspection method for detecting pattern distortion can be performed at the same time.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a surface inspection apparatus according to the present invention.

FIG. 2 is a diagram showing a lattice pattern and a captured image.

FIG. 3 is a flowchart illustrating a process for detecting a deformation defect.

FIG. 4 is a diagram showing another embodiment of the surface inspection apparatus according to the present invention.

[Explanation of symbols]

1 ... Photosensitive member seamless belt (inspection object), 2, 3 ... Cylindrical body, 4 ... Driving device, 5 ... Transmission belt, 6 ... Light source, 7 ...
Projection lens, 8 ... Diffusion plate, 9 ... Illumination device, 10 ... Imaging lens, 11 ... Imaging device, 12 ... Light source, 13 ... Slide, 14 ... Projector lens, 15 ... Projection device.

Claims (4)

[Claims] 1. Support means for supporting a belt-shaped object which is an object to be inspected, driving means for rotating the supporting means, and illumination means for illuminating the surface of the object to be inspected driven by the driving means. Projecting means for projecting a certain pattern on an imaging area on the surface of the inspection object, imaging area on the surface of the inspection object illuminated by the illumination means, and an image of the pattern projected on the imaging area. A surface inspection apparatus comprising: an image pickup means; and an image processing means for processing a picked-up image obtained by the image pickup means to detect a defect on the surface of the object to be inspected. 2. The surface inspection apparatus according to claim 1, wherein the pattern projected by the projection means is a grid pattern. 3. The surface inspection apparatus according to claim 1, wherein the pattern projected by the projection means is projection by infrared rays. 4. Support means for supporting a belt-shaped object which is an object to be inspected, drive means for rotationally driving the supporting means, and illumination means for illuminating the surface of the object to be inspected driven by the drive means. Projecting means for projecting a certain pattern on an imaging area on the surface of the inspection object, imaging area on the surface of the inspection object illuminated by the illumination means, and an image of the pattern projected on the imaging area. Image pickup means and image processing means for processing a picked-up image obtained by the image pickup means to detect defects on the surface of the object to be inspected, and the image pickup means picks up only visible light; A surface inspection apparatus comprising: an image pickup means for picking up only infrared rays.