JPH09300596A - Illumination device for printed matter checking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the quantity of light of irregular reflection light sources/regular reflection light sources and a transmitting light source and thereby improve the ability to detect the defect of printed matter by providing irregular reflection light sources and regular reflection light sources which are simultaneously turned ON during inspection and illuminate the surface of printed matter from the camera side and a transmitting light source which illuminates the rear face of printed matter from the opposite side. SOLUTION: This illumination device is equipped with an upper and a lower irregular reflection light sources 12A, 12B and a regular reflection light source 14 which illuminate the front face of a continuous printed matter S from the camera 10 side and a transmitting light source 16 which illuminates the rear face of the printed matter S from the opposite side to the camera 10. All these light sources are turned ON for use during inspection. In addition, the quantity of light of the irregular/regular reflection light sources and the transmitting light source 12A, 12B, 14, 16 is adjusted using each of adjusters. In this case, the irregular reflection light sources 12A, 12B contribute mainly to an inspection for the defect of the printed matter, the regular reflection light source 14 for the defective luster of a metal such as aluminum and the transmitting light source 16 for the defects such as pinholes in the printed matter S and The bleaching of the transparent film respectively. Thus, the balanced quantity of light of each of the light sources enables the high accuracy detection of defects to be performed per printed matter S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a printed matter inspection device, and more particularly to a lighting device for a printed matter inspection device which is suitable for inspecting a printed matter made of various kinds of material.

[0002]

2. Description of the Related Art Generally, in a gravure printing machine or the like, a belt-like printed material obtained by printing on a raw material is conveyed, while a camera such as a line sensor camera provided in an inspection device captures an image of the printed material. The inspection is performed based on the image data obtained at that time. In such a printed matter inspection apparatus, an illuminating device is used to illuminate the printed matter when a picture is taken by a camera.

By the way, in the above-mentioned gravure printing machine, not only paper but also a transparent film material or a reflection material such as aluminum foil or aluminum vapor-deposited paper is used as a printing material, and a plurality of kinds of printed matter can be printed on the same printing machine. Is being printed at. Therefore, in the conventional lighting device for a printed matter inspection device,
Mainly each time the printed material to be inspected is switched, the necessary light source is selected from the diffuse reflection light source, specular reflection light source, and transmission light source of the lighting device, and it is turned on / off to turn on various types. It corresponded to the inspection of printed matter.

[0004]

However, when a picture of a printed matter is picked up by a camera under the condition that a specific light source is turned on as in the prior art, the magnitude of the signal level of the input inspection image is delicate. However, there is a problem in that the ability to detect defects in printed matter is low because it cannot be adjusted.

The present invention has been made to solve the above-mentioned problems of the prior art. For example, when the types of original fabrics are different,
Even when inspecting different types of printed matter, it is an object to improve the detection capability of defects in the printed matter by making it possible to finely adjust the signal level of the inspection image input from the camera for each of the various printed matters.

[0006]

SUMMARY OF THE INVENTION The present invention is a lighting device for a printed matter inspection device applied to a printed matter inspection device for inspecting the printed matter on the basis of image data obtained by picking up an image of the printed matter with a camera. It is equipped with a diffuse reflection light source and a specular reflection light source that illuminate the front side of the printed matter from the camera side, and a transmissive light source that illuminates the back side of the printed matter from the opposite side of the camera. The above problem is solved by adopting a configuration including a light control unit that adjusts the light amounts of the light source and the transmission light source, respectively.

That is, in the present invention, when the image of the printed matter is picked up by the camera, all of the diffuse reflection light source, the specular reflection light source, and the transmission light source are turned on, and the light amount of each light source can be appropriately adjusted according to the object. As a result, it is possible to finely adjust the size of the signal level of the inspection image that is input as an image for each type of printed matter, and it is possible to improve the defect detection capability of the printed matter.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
In the printed matter inspection device illumination device, the dimming means is provided with a presetting means for resetting the light quantity of each light source based on the light quantity data stored in advance according to the type of the printed matter to be inspected. It is a thing. in this case,
It is possible to respond promptly when switching the printed matter to be inspected.

Another preferred embodiment of the present invention is
In the printed matter inspection device lighting device, the irregular reflection light source and the specular reflection light source are housed in the same housing and integrated. In this case, since each light source has conventionally been installed individually, it has become possible to easily install the lighting device which was troublesome to install in the printing machine.

Hereinafter, a more specific embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing the structure of a main part of an illumination device for a printed matter inspection apparatus according to an embodiment of the present invention.
FIG. 9 is a block diagram showing another main part.

The illumination device of the present embodiment includes a line sensor camera 10 for picking up an image printed on a belt-shaped original (printed material) S which is continuously conveyed in the direction of an arrow, and an image picked up by the camera 10. The present invention is applied to a printed matter inspection apparatus provided with an apparatus main body (not shown) that performs various kinds of processing for inspecting a printed matter for defects on the basis of image data that is sometimes input.

This illuminating device includes two upper and lower diffuse reflection light sources 12A for illuminating the surface of the original fabric S from the camera 10 side.
The light source 12B and the specular reflection light source 14 and the transmissive light source 16 that illuminates the back surface of the original fabric S from the opposite side of the camera 10 are provided, and all of these light sources are simultaneously turned on during the inspection. .

The diffuse reflection light sources 12A and 12B, the specular reflection light source 14, and the transmission light source 16 each extend in the width direction of the material S in the case and have a length exceeding the same width as shown in the sectional view in the drawing. A fluorescent lamp 18 is housed. A transparent glass plate 20A is fitted on the irradiation side of the case of the irregular reflection light sources 12A and 12B and fixed by a stopper 22, and the specular reflection light source 14 and the transmission light source 16 are also provided.
A milky white glass plate 20B that also serves as a diffusion plate is similarly fitted in the case (1) to expand the range of the optical axis.

The diffuse reflection light sources 12A and 12B are arranged so that their respective optical axes form an angle of 55 ° in the opposite direction with respect to the original S, and the specular reflection light source 14 has its original optical axis. It is arranged at a regular reflection position with respect to the optical axis of the camera 10 so as to form an angle of 8 ° with respect to the normal line of the anti-S. Further, the transmission light source 16 has an optical axis of the camera 10. It is arranged at a position that coincides with the optical axis.

Further, as shown in FIG. 2, the illumination device includes a dimmer 24 for adjusting the light amounts of the diffuse reflection light sources 12A and 12B, the specular reflection light source 14 and the transmission light source 16, respectively. The dimmer 24 is composed of a power supply box in which two diffuse reflection fluorescent lamp power supplies, a specular reflection fluorescent lamp power supply, and a transparent fluorescent lamp power supply are housed, and each of these power supplies has an output current variable type. Therefore, by adjusting the tube current of each fluorescent lamp of the diffuse reflection light sources 12A and 12B, the specular reflection light source 14, and the transmission light source 16 based on the set output values for these power supplies, The amount of light is adjusted.

In the present embodiment, the output current value for each power source of the dimmer 24 can be manually set, but the light amount of each light source for simultaneous lighting is easily reset. A presetting device 26 is attached so that the presetting device 26 can be used.

The preset device 26 is the same as the dimmer 24.
On the other hand, according to the type of the original fabric S to be inspected, it is configured by a computer that sets an output value to each power source in order to reset the light amount of each light source based on the light amount data stored in advance. ing. Further, a raw fabric species selector 28 is connected to the presetter 26, and any one of four types of buttons attached to the selector 28 is pressed to select the desired light intensity data of the raw fabric species. The output values for the respective fluorescent lamp power sources housed in the dimmer 24 are automatically set so that the light amounts are combined.

An example of the light quantity data stored in the preset device 26 is shown in Table 1 below. The buttons attached to the selector 28 correspond to the raw fabric species shown in Table 1.

[0020]

[Table 1]

In Table 1 above, the light quantity of each light source is shown as a percentage with 100 when the tube current of the fluorescent lamp is maximum.
Also, aluminum (dark) in the column of the original fabric is a printed matter in which the printed surface has a metallic glossy part such as aluminum and a dark pattern such as black. Aluminum (bright), on the contrary, is a metallic glossy part and white. It shows a case of a printed matter having a bright pattern such as. The light amount data as shown in Table 1 stored in the presetter 26 is not invariable, and the setting can be changed appropriately according to the change with time of the light amount of the fluorescent lamp.

Further, in the lighting device of this embodiment, as shown in the enlarged perspective view of FIG.
B and the specular reflection light source 14 are housed in the same housing 30, and are fixed and integrated with the housing 30.

That is, the frame 3 which constitutes the housing 30.
The diffuse reflection light sources 12A, 12 are provided on the walls on both sides in the longitudinal direction of 0A.
Both ends of B and the specular reflection light source 14 are fixed and integrated as a whole. Further, the housing 30 has a structure in which the side facing the camera 10 and the side facing the original fabric S are open, and light can be emitted from each light source toward the original fabric S and reflection at that time is possible. Light can be input by the camera 10.

In the present embodiment described in detail above, the output current of each fluorescent lamp power source in the dimmer 24 can be set so that the illumination light amount is a combination suitable for each material type. Therefore, it is possible to adjust the signal level of the inspection image line-input from the camera 10 to a size suitable for the inspection for each material type, and as a result, it is possible to significantly improve the defect detection capability of the printed matter. It will be possible.

Explaining this in more detail, the reason why three types of light sources are simultaneously turned on and used in this embodiment is as follows.
The purpose is to inspect with a single camera at the same time the print pattern, the metallic glossy portion, holes such as pinholes, and the presence or absence of color loss of ink on the transparent film. At that time, the irregular reflection light source is a defect of a printed pattern, the regular reflection light source is a defect of a metallic gloss portion such as aluminum,
The transmissive light source mainly contributes to the inspection of pinholes of the original fabric and the color defect of the transparent film respectively, and the balance of the light amount of each light source enables the above defects to be detected with high accuracy for each original fabric type. I am trying.

In addition to contributing to the detection of the pinholes and the like, the transmissive light source 16 also has a function of eliminating the influence of the background, which is a problem when the material is a transparent film. That is, in the case of a printed matter in which the transparent film is partially printed and the transparent portion is left, as shown in FIG. 4, assuming that the transparent portion is aligned with the optical axis of the camera, if the pattern portion exists behind it, Although it is erroneously detected due to the influence of the pattern portion, it is possible to mask the influence of the background by keeping the transmissive light source turned on. In this case, since the transmitted light is directly incident on the camera 10, the light amount of the transmitted light source 16 is small and sufficient. Therefore, as shown in Table 1, all the raw fabric species are set to 22%. .

The operation of this embodiment will be described in detail below.
As shown in FIG. 5, when the material to be inspected is a printed material in which the raw material is a transparent film and a triangular transparent portion is partially left, and the whole is printed with white ink, the light source is arranged in the same manner as in FIG.
In addition, by setting the illumination conditions in which the light sources are set to the light amounts shown in Table 1, the transparent portion can be clearly detected as shown in FIG.

On the other hand, as shown in FIG. 7, when a white transmission preventing plate is arranged without using a transmission light source and in order to avoid the influence of the background, the boundary line is broken in FIG. As shown in, almost no transparent part can be detected.

The same applies to the case where the raw material is white paper and the transparent portion is a hole such as a pinhole, and each light source is set to a combination of the light amounts of the raw material shown in Table 1 above. Thus, the holes present in the white paper can be clearly detected.

Next, the difference between aluminum (light) and (dark) will be described. When the printed matter is a bright one in which a white pattern is printed on the aluminum original fabric as shown in FIG. 9, the lighting conditions are shown for each light source as shown in FIG. By setting the light intensity data of aluminum (bright) in Table 1 (regular reflection light source: 25%), the contrast between aluminum and white can be increased, so a white pattern can be clearly detected as shown in FIG. can do.

On the other hand, as shown in FIG. 12, in the case of a dark printed material in which a black pattern is printed on the aluminum original fabric, the illumination condition is conceptually shown in FIG.
By setting the value of the light amount data of aluminum (dark) increased to%, it is possible to clearly detect a black pattern as shown in FIG.

As described in detail above, according to this embodiment,
By setting each of the light sources 12A, 12B, 14 and 16 to a light amount of illumination composed of a combination suitable for each material type, the signal level of the inspection image input from the camera 10 has a size suitable for the inspection. It becomes possible to adjust to, and as a result, it becomes possible to greatly improve the detection capability.

Further, by mounting the diffuse reflection light sources 12A and 12B and the regular reflection light source 14 in one housing 30 and integrating them, it becomes possible to easily install the light sources on the printing machine.

The present invention has been specifically described above, but the present invention is not limited to the one shown in the above-mentioned embodiment, and various modifications can be made without departing from the gist thereof.

For example, the installation angles of the camera 10 and each light source with respect to the original fabric S are not limited to those shown in the above embodiment. However, it is desirable that the camera 10 and the specular reflection light source 14 be as close to the normal line as possible without interfering with each other.

The light quantity data set for each light source is not limited to those shown in Table 1, and the types of printed matter are not limited to the four kinds shown in the table.

[0037]

As described above, according to the present invention, the illumination light amount of each light source can be arbitrarily set for each type of printed matter such as the type of original, so that the signal level of the inspection image is suitable for inspection. Can be set to different sizes,
It is possible to significantly improve the ability to detect defects in printed matter.

When the diffuse reflection light source and the specular reflection light source are housed in a single casing, the light sources of both types can be integrated to facilitate the installation of the light source on the printing machine.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a main part of a lighting device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing another main part of the lighting device.

FIG. 3 is an enlarged perspective view showing a light source integrated in a housing.

FIG. 4 is an explanatory diagram showing a relationship between a background and a malfunction of transparent portion detection.

FIG. 5 is a plan view showing an example of a printed material of an original transparent film.

FIG. 6 is an explanatory view showing a detected image of the printed matter according to the present invention.

FIG. 7 is an explanatory diagram showing illumination conditions of a comparative example that does not use a transmissive light source.

FIG. 8 is an explanatory diagram of a detected image of the printed matter when a transmissive light source is not used.

FIG. 9 is a plan view showing a printed material of an aluminum original sheet on which a bright pattern is printed.

FIG. 10 is an explanatory view conceptually showing the lighting condition of aluminum (bright).

FIG. 11 is an explanatory diagram showing an inspection image under an aluminum (bright) illumination condition.

FIG. 12 is a plan view showing a printed material of an aluminum original sheet on which a dark pattern is printed.

FIG. 13 is an explanatory view conceptually showing an illumination condition of aluminum (dark).

FIG. 14 is an explanatory diagram showing an inspection image under aluminum (dark) illumination conditions.

[Explanation of symbols]

 10 ... Licensor camera 12A, 12B ... Diffuse reflection light source 14 ... Regular reflection light source 16 ... Transmission light source 18 ... Fluorescent light 20A ... Transparent glass plate 20B ... Milky white glass plate 22 ... Stopper 24 ... Dimmer 26 ... Preset device 28 ... Original fabric Species selector 30 ... Casing S ... Original

Claims (3)

[Claims] 1. A illuminating device for a printed matter inspection device, which is applied to a printed matter inspection device for inspecting the printed matter based on image data obtained by picking up an image of the printed matter with a camera, which is simultaneously turned on at the time of inspection and is used. A diffuse reflection light source and a specular reflection light source that illuminate the front side of the printed matter from the side, and a transmission light source that illuminates the back side of the printed matter from the opposite side of the camera are provided, and the light amounts of the diffuse reflection light source, the specular reflection light source, and the transmission light source are respectively An illumination device for a printed matter inspection device, comprising an adjusting light adjusting means. 2. The presetting means for resetting the light quantity of each light source based on the light quantity data stored in advance according to the type of printed matter to be inspected, according to claim 1. An illumination device for a printed matter inspection device, which is provided. 3. The illumination device for a printed matter inspection apparatus according to claim 1, wherein the irregular reflection light source and the specular reflection light source are housed and integrated in the same housing.