JPH09292348A - Printed surface inspector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the efficiency of inspection by positively detecting all defects of the printing surface of a mirror-shaped body under inspection and eliminating misinspections and to obtain an inexpensive printed surface inspector. SOLUTION: In an imaging device 5 of a printed surface inspector 1, a color camera 7 is arranged at an approximately central part, and a plurality of black and white cameras 8 are arranged at the outer surface of the color camera 7. Then an optical axis L of the color camera 7 is made to match with the approximately center part of a printed surface 3 of a mirror-surface shaped body under inspection 2. With the optical axis L of the color camera 7 as the center, optical axes (d) of a plurality of the black and white cameras 8 are arranged at the positions, which are divided at equal distance to the outer surface and at equal angles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for inspecting a printed surface condition of characters, graphics, etc. printed on the surface of an inspection object such as a compact disk (hereinafter, referred to as a CD).

[0002]

2. Description of the Related Art Generally, in order to display recorded contents and the like on a CD, a maker name, a song name, a player name, and the like are printed on the surface of the CD. As an inspection device for inspecting whether or not there is a defect in the printing state, there is, for example, Japanese Patent Laid-Open No. 5-945.
No. 17, “Image input device for optical inspection device”,
A plurality of imaging devices (two CCD cameras) are used to detect defects on the printing surface. Also, in order to satisfy high resolution and high speed, four CD cameras are used, and one CD
It also describes a configuration in which the image is divided into four and photographed. However, in the above publication, there is no description as to whether the camera is for color or black and white, and a configuration using four color CCD cameras is also conceivable, but it is not realistic in terms of price, etc.
It is presumed that it is a configuration using a stand.

[0003]

Conventionally, one color camera is used as an image pickup device of a printing surface inspection device, or four black and white cameras are used as shown in the conventional example to obtain one image. There was a method to divide a CD into four and shoot.
However, there are the following problems.

The former has only one color camera and therefore has a low resolution and cannot detect minute defects. Therefore, if the number of color cameras is increased (for example, four) in order to increase the resolution, the image pickup apparatus becomes expensive. Further, the color camera is more expensive than the monochrome camera in the image processing device located in the subsequent stage of the image pickup device, and the image processing device becomes expensive as the number of color cameras is multiplied.
However, the advantage of the color camera is that the amount of information (color information of R, G, B) is three times as large as that of the monochrome camera, and color discrimination is possible.

In the latter case, the cost of each camera and image processing apparatus is lower than that of a color camera, and since four black and white cameras are used for photographing, the resolution is high and minute defects can be detected. However, the monochrome camera can discriminate the color density, but cannot discriminate the color because the color information is missing.

As described above, both the former and the latter have merits and demerits. This application is intended to solve the drawbacks of the conventional image pickup apparatus. A black and white camera detects a minute defect on a printing surface, and a color camera detects a color defect. It is intended to realize a printing surface inspection device having an image pickup device that is inexpensive and is inexpensive.

[0007]

In order to solve the above problems, the present invention provides a plurality of image pickup devices for illuminating a print surface of an object to be inspected with an illuminating device and photographing reflected light from the print surface. In the printing surface inspection apparatus including the image pickup device, the image pickup device has a color camera arranged substantially in the center and a plurality of black and white cameras arranged on the outer periphery of the color camera.

Further, the image pickup device is one in which the optical axes of a plurality of black and white cameras are arranged at equal distances from the optical axis of the color camera to the outer periphery of the optical axis.

Further, in the image pickup device, the optical axis of the monochrome camera is arranged at positions divided by an equal distance from the optical axis of the color camera to the outer periphery and an equal angle with the optical axis of the color camera as the center. It is a thing.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The printing surface inspection apparatus of the present invention is a CD
An illumination device that irradiates a printing surface of a mirror-like inspection object such as the above, an imaging device that captures reflected light from the printing surface, and an image processing device that analyzes an image captured by the imaging device.

The image pickup device has one color camera arranged substantially in the center and four black and white cameras arranged on the outer periphery of the color camera.

In the image pickup device, the optical axis of the color camera is aligned with the approximate center of the printed surface of the mirror-like inspection object, and four black and white cameras are provided around the optical axis of the color camera. Are arranged parallel to each other, and the optical axes of the four black-and-white cameras are arranged at equal distances outward from the intersection of the diagonals on the diagonal intersecting at right angles with the intersection of the optical axes of the color cameras. Arrange a black and white camera so that it comes.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the main configuration of the CD printing surface inspection apparatus in the embodiment. FIG. 2 is a sectional view taken along line xx of the CD printing surface inspection apparatus in the embodiment. FIG. 3 is a yy arrow view of the CD printing surface inspection apparatus in the embodiment.

As shown in FIGS. 1, 2 and 3, the CD printing surface inspection device 1 includes an image pickup device 4 for photographing reflected light from the printing surface 3 of the CD 2 and an illuminating device 5 for irradiating the printing surface 3. And a body frame 6 for fixing the respective devices. The image pickup device 4 includes one color CCD camera 7, 4
It is composed of a black and white CCD camera 8 and an image processing device (not shown) for analyzing an image taken by each CCD camera. The illumination device 5 includes an inspection table 9 on which the CD 2 is placed, a fluorescent illumination device 10, a halogen illumination device 11, and a half mirror 12.

The CD 2 is placed substantially in the center of the inspection table 9 with the printing surface 3 facing upward, centered on the optical axis L of the image pickup device. Above the half mirror 12, a color CCD camera 7 and a monochrome CCD camera 8 as the image pickup device 4 are fixed. The color CCD camera 7 is fixed to the upper part of the camera mounting frame 14 by the camera mounting bracket 13. The black-and-white CCD camera 8 is arranged below the camera mounting frame 14 so that the optical axes d of the four cameras are evenly outward from the intersections of the two diagonal lines s intersecting at right angles. , The intersection coincides with the optical axis L of the color CCD camera 7. After adjusting the position of the image in the X and Y directions, the upper part of the camera mounting frame 14 is adjusted by the image adjusting bracket 15 to attach the imaging device mounting frame 18.
Is fixed to the bottom of the camera mounting frame 14, and the abutment metal fitting 1 is attached.
6 is attached, and the contact metal fitting 16 is brought into contact with the inner circumference of the contact frame 17 to prevent the optical axis of the CCD camera from swinging. The imaging device mounting frame 18 and the contact frame 17 are fixed to the inner wall of the main body frame 6.

The inspection table 9 is covered with, for example, a black cloth so as not to reflect light from the half mirror 12 and the ring-shaped fluorescent lamp 19 (hereinafter referred to as fluorescent lamp). The fluorescent lighting device 10 is composed of a fluorescent lamp 19, a fluorescent lighting frame 20 and a diffusion plate 21.
Is fixed to the lower portion of the main body frame 6 between the CD 2 and the half mirror 12 in parallel with the CD surface. Inside the fluorescent lighting device 10, a fluorescent lamp 19 whose center coincides with the optical axis L is fixed to the fluorescent lighting frame 20 in parallel with the CD surface. A diffuser plate 21 is fixed to the bottom of the fluorescent illumination frame 20 in parallel with the CD surface. The diffusion plate 21 is the half mirror 12.
A circular hole 22 sufficient to allow the reflected light from the sheet to the printing surface 3 to pass therethrough is provided with its center aligned with the optical axis L. The diffusing plate 21 diffuses the light from the fluorescent lamp 19 and radiates uniform diffused light to the printing surface.

The halogen lighting device 11 includes a surface lighting device 23.
And a fiber cable 25 that connects the halogen light source 24 and the surface lighting device 23.
The halogen light guided by the fiber cable 25 becomes a plane parallel light beam by the surface lighting device 23, and the plane parallel light beam is diffused by a diffusion plate 26 fixed in parallel to the front surface of the surface lighting device to obtain a uniform diffused light. Is emitted toward the half mirror 12.

The half mirror 12 arranged in the optical path formed between the CD and the CCD camera is a surface illumination device 2.
The diffused light from 3 is reflected toward the printing surface 3. here,
The half mirror 12 has a body frame 6 at an angle θ = 45 ° with the optical path.
It is fixed to. The reflected light from the printing surface 3 that has passed through the half mirror 12 is read as an image by the color CCD camera 7 and the monochrome CCD camera 8. An image processing device (not shown) is provided at the rear stage of each CCD camera, processes an image from the CCD camera, and determines an image defect.

The halogen light source 24 is located between the halogen lamp 27 that emits light, a condenser lens 28 that condenses the light emitted from the halogen lamp 27, and the halogen lamp 27 and the condenser lens 28. The shutter plate 30 is constituted by shutter means 30 which interrupts the light by blocking the optical path connecting the condenser lens 28 and the condenser lens 28 with a shutter plate 29.

As shown in FIG. 4, the shutter means 30 comprises a rotary solenoid 31 and a substantially rectangular shutter plate 29 fixed to its drive shaft.
Then, when the rotary solenoid 31 is electrically turned on, the locus is moved in a circular arc locus which is positioned in the vertical direction with respect to the optical path.
The shutter plate 29 fixed to the drive shaft of the tally solenoid 31 rotates a predetermined angle (in the direction of arrow e), opens the optical path connecting the halogen lamp 27 and the condenser lens 28, and the halogen light source 24 emits halogen light. Rotary solenoid 3
When 1 is turned off, the shutter plate 29 returns to the original position (in the direction of arrow c), the optical path connecting the halogen lamp 27 and the condenser lens 28 is blocked, and the halogen light is stopped.

The main body frame 6 encloses the illumination space up to the color CCD camera 7, the monochrome CCD camera 8, the half me 12, and the surface illuminating device 23 of the halogen illuminating device 11 with a black side wall, and external light I try not to get inside this lighting system.

Next, the types of defects that occur on the printing surface 3 are
There are two types, a defect in which the black and white CCD camera 7 detects a minute density difference (hereinafter referred to as a density difference defect) and a defect in which a color CCD camera determines a hue (hereinafter referred to as a hue defect). As shown in FIG. 5, the density difference defect includes a pinhole (a) due to dust or air bubbles mixed in the ink, a blur (b) or bleeding (c) of the printing ink, and a scratch ( d), foreign matter mixed with dust remaining inside the transparent film that protects the aluminum reflection film (e),
Dust or the like adheres to the transparent protective film that protects the aluminum reflective film, and there is a pock mark (f) or the like, which is a trace of the dust, and can be detected only by the monochrome CCD camera 7.

In this embodiment, one color CCD camera 7 and four monochrome CCD cameras 8 are used as the image pickup device. The above-mentioned hue defect has one color C even if the resolution is low.
It is arranged at a position where the CD camera 7 can take a picture sufficiently and the whole of the CD can be taken. The density difference defect requires high resolution and requires four black and white CCD cameras 8
Are arranged on the outer periphery of the color CCD camera 7, the CD is divided into four, and the divided four pieces are detected by the respective black and white CCD cameras as shown in FIG.

Next, the operation of this embodiment having such a configuration will be described.

When detecting with the color CCD camera 7 (hue defect), the fluorescent lamp 19 of the fluorescent lighting device 10 is electrically turned on, and the halogen light emitted from the halogen light source 24 is mechanically turned off (shutter plate 29). Shield with). Then, ring-shaped light is emitted from the fluorescent lamp 19 toward the diffuser plate 21, and the diffuser plate 21 diffuses the ring-shaped light from the fluorescent lamp 19 and places a uniform diffused light on the inspection table 9. The printed surface 3 of the placed CD 2 is radiated. The reflected light reflected from the printing surface 3 passes through the half mirror 12, is photographed by the color CCD camera 7, and is imaged by an image processing device (not shown) located after the color CCD camera 7. A hue defect is determined.

When detecting with the black and white CCD camera 8 (density difference defect), the halogen light generated from the halogen light source 24 is mechanically turned on (the shutter plate 29 is opened), and the fluorescent lamp 19 of the fluorescent lighting device 10 is electrically turned on. Off. Then, the light emitted from the halogen light source 24 is guided to the surface illuminating device 23 by the fiber cable 25, converted into plane parallel light by the surface illuminating device 23, and the plane parallel light is diffused by the diffusion plate 26 to be uniformly diffused. Light is half mirror 1
It is radiated toward 2. The half mirror 12 makes the diffused light θ
The light is reflected toward the printing surface 3 of the CD 2 at an angle of = 45 degrees. Then, the light reflected from the printing surface 3 is reflected by the half mirror 12.
After passing through, the CD surface is divided into four by four black and white CCD cameras 8, and the black and white CCD cameras 8 are taken.
An image processing device (not shown) located in the subsequent stage identifies the density difference defect.

[0027]

The present invention is embodied in the form described above and has the following effects.

By arranging a color camera in the center and arranging a plurality of black and white cameras in the periphery, a well-balanced image pickup arrangement can be obtained, and both the defect inspection of the hue defect and the density difference defect can be carried out, and It is possible to reliably detect all the defects, reduce defects due to omission of defect detection, and improve the quality of the inspection object.

By using as few expensive color cameras as possible and using a plurality of inexpensive black-and-white cameras, it is possible to realize a printing surface inspection apparatus using an inexpensive imaging device.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram showing a main configuration of an embodiment of a CD printing surface inspection apparatus of the present invention.

FIG. 2 is a sectional view of the imaging device taken along line xx.

FIG. 3 is a yy arrow view of the same fluorescent lighting device.

FIG. 4 is a perspective view of a main part of a shutter device for a halogen light source.

FIG. 5 is an explanatory diagram illustrating the types of density difference defects that occur on the printing surface of a CD.

FIG. 6 is an explanatory diagram illustrating a positional relationship between a CD and a CCD camera.

[Explanation of symbols]

2 Inspection object (CD) 3 Printing surface 5 Illumination device 4 Imaging device 1 Printing surface inspection device 7 Color camera (color CCD camera) 8 Black-and-white camera (black-and-white CCD camera) L Optical axis of color camera (optical axis of color CCD camera) ) D Optical axis of monochrome camera (optical axis of monochrome CCD camera)

Claims (3)

[Claims] 1. A printing surface inspection apparatus comprising a plurality of imaging devices for illuminating a printing surface of an object to be inspected with an illuminating device and photographing reflected light from the printing surface, wherein the imaging device has a color camera in the center. And a plurality of black-and-white cameras on the outer circumference of the color camera. 2. The image pickup device has optical axes of a plurality of black and white cameras arranged at equal distances from the optical axis of the color camera to the outer periphery with the optical axis of the color camera as the center. The printing surface inspection apparatus according to claim 1. 3. The image pickup device is arranged such that the optical axis of the color camera is centered on the optical axis of the color camera, and the optical axis of the monochrome camera is located at positions divided by an equal distance from the optical axis of the color camera to the outer circumference. The printed surface inspection apparatus according to claim 1, wherein the printed surface inspection apparatus is provided.