JP3316381B2 - Printing surface inspection device - Google Patents

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 the printing state is defective, for example, Japanese Patent Application Laid-Open No. 5-945
No. 17, “Image input device for optical inspection device”
An image pickup device (two CCD cameras) is used to detect a defect on a printing surface. The camera of this imaging device has a structure in which a lens is tilted by an angle Θ and a reflection image from a mirror-like inspection object is not reflected on the imaging device.

[0003]

Conventionally, the camera remains fixed at a fixed position except for a camera having a structure in which the camera of the image pickup apparatus of the printing surface inspection apparatus is inclined at a fixed angle as shown in the prior art. There were many things.

In general, a printing surface inspection device is often installed in a printing press and installed in a limited space of the printing press, and the design of the printing surface inspection device is very limited. In many cases, they struggle. Also, in a printing surface inspection apparatus installed in the limited space, if the printed image of the inspection object (CD or the like) on the transport line of the printing press does not match the image standard of the camera, the monitor of the printing surface inspection device is not used. The image displayed on the upper part is displaced from the printed image, and becomes very difficult to see.

[0005] For this purpose, the printing surface inspection apparatus must be capable of freely changing the mounting direction of the camera in accordance with the direction of the inspection object on the transport line after being installed on the printing press.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a camera for photographing a printed surface of an inspection object,
In a printing surface inspection apparatus having fixing means for fixing a camera to a main body frame, a camera having an optical axis coaxial with a central axis of an object to be inspected, and the camera being rotatable about the optical axis on the main body frame And fixing means for rotating the camera around the optical axis in accordance with the design direction of the printing surface.

Further, the fixing means rotates the camera about the optical axis in accordance with the printing direction of the printing surface.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises a color camera at a substantially central portion of a printing surface inspection apparatus, and a fixing means for fixing a plurality of black-and-white cameras around the color camera to a frame of the printing surface inspection apparatus main body. After adjusting between the frame and the optical axis of the color camera around the optical axis of the color camera, rotating and adjusting the image of the printing surface of the inspection object or the printing direction of the printing surface to the image reference of the camera, and then adjusting the reference. , To be fixed to the body frame.

[0009]

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 illustrating a main configuration of a CD printing surface inspection apparatus according to an embodiment. FIG. 2 is a sectional view of the CD printing surface inspection apparatus taken along line xx in the embodiment.

As shown in FIGS. 1 and 2, a CD printing surface inspection apparatus 1 includes an imaging device 4 for photographing reflected light from a printing surface 3 of a CD 2, an illumination device 5 for irradiating the printing surface 3, and a respective device. It is composed of a body frame 6 for fixing the device. The imaging device 4 includes one color CCD camera 7, four black and white CCD cameras 8, and fixing means 9 for fixing each CCD camera to the main body frame. An image captured by the imaging device 4 is an image processing device (not shown)
To detect defects.

The CD 2 is placed substantially at the center of the inspection table 10 with the printing surface 3 facing upward, centered on the optical axis L of the color CCD camera 7. Above the half mirror 11, a color CCD camera 7 as an image pickup device 4, a monochrome CCD camera
The D camera 8 is fixed by fixing means 9.

The fixing means 9 includes a camera mounting bracket 12, a camera mounting frame 13, an image adjusting bracket 14, a slide 40, an image pickup device mounting frame 17, and a fixing screw 42. The color CCD camera 7 is fixed to an upper portion of a camera mounting frame 13 by a camera mounting bracket 12. The black-and-white CCD camera 8 is disposed below the camera mounting frame 13 such that the optical axes d of the four cameras are located at equal positions outside the intersection of two diagonal lines s that intersect at right angles. ,
The intersection coincides with the optical axis L of the color CCD camera 7. The upper part of the camera mounting frame 13 is fixed to the image adjustment fitting 14. One locking piece 40 is mounted on the imaging device mounting frame 17 at a position located on the upper surface of the image adjustment metal fitting 14 and opposed to one image adjustment metal fitting 14.

The slide piece 40 has an arc-shaped slit groove 41 having a radius centered on the optical axis L of the color CCD camera 7.
However, the width of the fixing screw 42 is large enough to penetrate it, and an angle of 45 ° about the optical axis of the color CCD camera 7 is opened in a range in which the imaging device mounting frame 17 can rotate. It penetrates the arc-shaped slit groove 41, is temporarily fixed to the image adjustment fitting 14 by a tightening force enough to freely rotate the image adjustment fitting 14, rotates the image adjustment fitting 14, and prints the printing surface 3. Or the printing direction of the print surface 3 (the direction of moving the squeegee in screen printing) and the horizontal or vertical reference of the camera screen, and then fully tighten the fixing screw 42. At the lower part of the camera mounting frame 13, a contact fitting 15 is provided.
The contact fitting 15 is brought into contact with the inner periphery of the contact frame 16 to prevent the optical axis of the CCD camera from swinging. The imaging device mounting frame 17 and the contact frame 16 are fixed to the inner wall of the main body frame 6.

Next, a process of detecting a defect on the printing surface 3 in this embodiment will be described.

The light emitted from the illuminating device 5 is
Is radiated. The reflected light from the printing surface 3 transmitted through the half mirror 11 is transmitted to the color CCD camera 7 and the black and white CC camera.
The image is read by the D camera 8 as an image. An image processing device (not shown) is provided at a stage subsequent to each CCD camera, and processes an image from the CCD camera.
Detect image defects.

Next, in this embodiment, the relationship between the image g of the printing surface 3 and the camera image will be described.

If the horizontal or vertical reference of the image g of the printing surface 3 and the camera image does not match, the image projected on the monitor looks oblique and very difficult to see.

Next, in this embodiment, the relationship between the printing direction of the printing surface 3 and the camera image will be described.

As shown in FIGS. 3 and 4, in screen printing, linear color spots c occur in the printing direction b (the direction in which the squeegee 43 is moved). The cause of this defect is squeegee 4
When the squeegee 43 is damaged or the foreign matter e mixed in the ink is bitten by the squeegee 43, the ink swells or is thinly removed, and a linear color spot defect occurs.
Therefore, the direction in which the linear color spot defect occurs depends on the squeegee 43.
Occurs only in the moving direction b. Therefore, when the parallel or vertical reference of the screen of the camera is matched with the printing direction b of the printing surface 3, the linear color spot defect can be easily identified. That is, when the defect is determined by the image processing, the image is scanned and divided into pixels in order to determine the density based on the density of the image. If so, a regular difference in shading appears in the same direction, so that the image processing unit can easily detect a defect.

In the present embodiment, the camera can be rotated up to an angle of 45 ° at the maximum, and can cope with all directions around the color CCD camera 7. For this reason, it is possible to design without worrying about the direction of the camera at the time of installation on the printing press, and it is only necessary to adjust the direction of the camera after installation.

[0021]

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

When the printing surface inspection apparatus is installed in a limited space by rotating the fixing means, it is possible to design the printing surface inspection apparatus in consideration of the surroundings without worrying about the camera direction. Can be easily incorporated into

Also, by adjusting the position of the camera to the print image, the monitor screen is easy to see and the usability is good.

Further, by aligning the image of the camera with the printing direction, it is easy to detect a linear color spot defect occurring in the printing direction.

[Brief description of the drawings]

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

FIG. 2 is an xx sectional view of the imaging device.

FIG. 3 is an explanatory diagram showing a positional relationship between a printing direction and a foreign substance in screen printing.

FIG. 4 is an explanatory diagram of a linear color spot defect occurring on a printing surface of a CD.

[Explanation of symbols]

 2 Inspection object (CD) 3 Printing surface 4 Imaging device 1 Printing surface inspection device (CD printing surface inspection device) 7 Camera (CCD camera for color) 8 Camera (CCD camera for black and white) 6 Main body (body frame) 9 Fixed Means g Print image L Optical axis of camera b Printing direction

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 21/88-21/95 B41F 33/14

Claims (2)

(57) [Claims] 1. A printing surface inspection apparatus comprising: a camera for photographing a printing surface of an object to be inspected; and fixing means for fixing the camera to a main body frame, wherein an optical axis coaxial with a central axis of the object to be inspected is provided. Having a camera and a fixing means for fixing the camera to the main body frame so as to be rotatable around the optical axis, the fixing means aligning the camera with a design direction of the printing surface, A printing surface inspection device, wherein the printing surface inspection device is rotated about the optical axis. 2. The printing surface inspection apparatus according to claim 1, wherein said fixing means rotates said camera around said optical axis in accordance with a printing direction of said printing surface.