JPH09136403A - Monitor for printed matter having gloss part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To monitor a printed matter in which material texture is given by printing transparent varnish partially or decoration to mirror-reflect a gold color and a silver color is made by a method in which the printed matter having a gloss part is irradiated coaxially, and mirror reflection light is incident upon an image pick-up means. SOLUTION: Illumination light emitted from a light source 4 is collimated into a parallel beam by a collimator lens 5, reflected by a half mirror 6 to be vertically incident upon a printed matter 1, and reflected by a mirror to be incident upon a TV camera 7 after passing through the half mirror 6. The illumination light is made to coaxially fall on the TV camera 7, the mirror- reflected light of the printed matter 1 is incident, and an image is picked up so that a gloss part such as a varnish part and a gold and silver color part is embossed on a part of faint color of grain. When an image is picked up slantingly instead of the coaxial irradiation, the image can be distorted or got dim partially. When the light is not parallel rays, although mirror reflection light from the gloss part becomes heterogeneous, the generation of these phenomena is prevented by the present apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring device for monitoring whether a printed matter having a glossy portion such as gold or silver has been printed correctly.

[0002]

2. Description of the Related Art A printed matter printed on a plate cylinder and having the same pattern repeatedly appearing thereon is picked up and displayed as a still image, and proper printing is monitored. In this case, the illumination is performed obliquely, and the reflected light is captured by a television camera or the like to display an image.

[0003]

The printed matter has a transparent varnish printed on a light-colored portion of the wood grain so as to give a feeling of being close to the real thing, and a glossy portion decorated with gold or silver. There is something. These are problems that when the scattered light from the object is input to the image pickup device as in normal imaging, it does not look like the real thing, and in the case of gold or silver, it becomes black and the color of gold and silver does not appear in the image. was there.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to image a printed matter having a glossy portion in a raised manner.

[0005]

In order to achieve the above object, according to the invention of claim 1, a light source unit for irradiating a parallel light beam, a half mirror for reflecting the parallel light beam, and a light beam reflected by the half mirror are objects. And a regular reflection light from the object is transmitted through the half mirror to receive the light, and the object is a printed matter having a glossy portion.

By irradiating a parallel light beam with a half mirror coaxially from the same direction as the image pickup means and by picking up an image of the specularly reflected light, the glossy portion of the printed matter can be made to stand out and picked up.

According to the second aspect of the present invention, the printed matter having the glossy portion is to be monitored when a transparent varnish is printed on a light-colored portion of the grain with a pattern representing the grain. A printed matter with a transparent varnish applied to the light-colored portion of the wood grain is coaxially illuminated by parallel rays, and the image of the specularly reflected light has the wood grain raised, and an image with a feeling close to the real thing can be obtained.

According to the third aspect of the present invention, the printed matter having the glossy portion is the object to be monitored, in which gold or silver is partially printed. The portion painted in gold or silver has a large amount of specular reflection light but a small amount of scattered light, so the image captured by the scattered light becomes a dark image. On the other hand, the image of the specularly reflected light is an image in which the gold or silver portion is bright and stands out.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. The same pattern is repeatedly printed on the printed matter 1 by the plate cylinder 2, and each pattern has a transparent varnish printed on the light-colored portion of the wood grain,
Some are partially printed in gold or silver. The object 1 is traveling in the direction of the arrow by the plate cylinder 2 and a transport roller (not shown). An encoder 3 is connected directly to the rotary shaft of the plate cylinder 2 or via a gear or the like, and outputs the rotational position of the plate cylinder 2 as a pulse signal.

The light source 4 is a flash light source and a strobe is used. The collimator lens 5 collimates the light from the light source, and the light source 4 is arranged at the position of the focal length f of the collimator lens 5. The half mirror 6 reflects parallel rays from the collimator lens 5, bends them at a right angle, makes them vertically incident on the object 1, and transmits specularly reflected light from the printed matter 1. The television camera 7 receives this specularly reflected light. The television camera 7 uses a two-dimensional image sensor, for example, three CCDs (Charge
A 3CCD color television camera using a Coupled Device).

The timing control circuit 8 inputs the pulse signal of the encoder 3, and the predetermined portion of the pattern printed on the plate cylinder 2 is determined by the diameter of the plate cylinder 2 and the distance between the axis of the plate cylinder 2 and the center position of the TV camera. The number of pulses until moving to the center of 7 is counted, the light emission timing signal is sent to the light source 4, the television camera 7 takes a timing signal to pick up the image, and the image processing circuit 9 takes in the picked up image into the image memory. Generate a signal. The image processing circuit 9 stores the image input from the television camera 7 in the built-in image memory and displays it on the screen of the monitor 10 as a still image.

With the above-described structure, the illumination light emitted from the light source 4 becomes parallel rays by the collimator lens 5, is reflected by the half mirror 6 and is vertically incident on the printed matter 1, and is specularly reflected and transmitted by the half mirror 6. It is incident on the TV camera 7.
In this way, the illumination light is coaxially irradiated and enters the television camera 7, whereby the specularly reflected light of the printed material 1 is incident, and glossy parts such as a varnish part and a gold or silver part stand out in the light-colored part of the wood grain. Is imaged as. When the image is captured obliquely instead of such coaxial irradiation, the image is distorted or partially blurred. If the light rays are not parallel rays, the regular reflection light from the glossy portion becomes non-uniform, but these phenomena do not occur according to the present invention.

FIG. 2 shows another optical system for converting the irradiation light incident on the half mirror into parallel rays, and the same reference numerals as those in FIG. 1 have the same functions. (A) shows a case where irradiation light from the light source 4 is converted into parallel rays by the parabolic mirror 11.
In (b), as in the case of FIG. 1, the collimator lens 5 is used to convert the light from the light source into parallel rays, which are then bent at a right angle by a mirror 12 and then incident on a half mirror 6. Thereby, the optical path can be downsized.

In the embodiment shown in FIG. 1, the television camera 7 is used as the image pickup means, but it may be a linear sensor and operated by a timing signal from the timing control circuit 8. In this case, the light source 4 is always illuminated. Further, although the light emission timing and the image pickup timing are determined by the encoder 3 coupled to the plate cylinder 2, in the case of color printing, a register mark used for register control for preventing color misregistration can be used. A register mark such as a cross mark is often used, but this is detected and a predetermined portion of the printed pattern is imaged based on the distance between the position of the detector and the center position of the image pickup device and the traveling speed of the printed matter. The timing of entering the field of view of the device can be known, and light emission and imaging can be performed at this timing.

[0015]

As is apparent from the above description, according to the present invention, the specularly reflected light is made incident on the image pickup means by coaxially irradiating the printed matter having the glossy portion, so that the portion such as wallpaper can be obtained. It is effective for printing a transparent varnish to give a sense of quality, and for monitoring printed matter with a specular reflection such as gold or silver.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

2A and 2B show another example of an optical system in which parallel light is incident on a half mirror, FIG. 2A shows a case where a parabolic mirror is used, and FIG. 2B shows a case where a mirror is used to reduce the size. Is.

[Explanation of symbols]

 1 Printed matter 2 Plate cylinder 3 Encoder 4 Light source 5 Collimator lens 6 Half mirror 7 TV camera 8 Timing control circuit 9 Image processing circuit 10 Monitor 11 Parabolic mirror 12 Mirror

Claims (3)

[Claims] 1. A light source unit for irradiating a parallel light beam, a half mirror for reflecting the parallel light beam, a reflected light beam of the half mirror irradiates an object, and specularly reflected light from the object is directed to the half mirror. An apparatus for monitoring a printed matter having a glossy portion, characterized in that the object is a printed matter having a glossy portion. 2. The printed matter having a glossy portion according to claim 1, wherein the printed matter having a glossy portion is printed with a transparent varnish on a light-colored portion of the grain with a pattern showing a grain. Monitoring equipment. 3. The monitoring device for printed matter having a glossy portion according to claim 1, wherein the printed matter having the glossy portion is partially printed with gold or silver.