JPS6365886B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical inspection head used in an image area measuring device for panels such as printing plates for offset printing.

The pattern area measuring device, which measures the pattern area ratio of panels used in offset printing, etc., attaches and fixes the panel to be measured (including metal plates, resin films, etc.) on a table on the front of the main body housing. The optical inspection head is adapted to be scanned in a moving manner. By this movement and scanning of the inspection head, the picture area ratio on the panel surface is measured and optically measured.

The optical inspection head has an illumination optical system that performs slit exposure on the panel surface, and an optical inspection device that receives reflected light from the slit-exposed panel surface, and these are mounted on a movably mounted head. installed in the casing. An optical inspection device optically detects the intensity of reflected light from the panel surface.

On the other hand, the panel to be measured, such as a printing plate for offset printing, is
Calibration marks are attached to areas (areas that do not adversely affect printing), and these calibration marks function as picture measurement standards.
Therefore, when measuring the pattern area ratio of a panel by moving and scanning the inspection head, the intensity of the reflected light from the calibration mark can be accurately measured without being affected by the reflected light from other areas of the panel. Must.

In consideration of the above-mentioned points, this invention has a simple structure in which a light shielding plate is provided in the calibration mark area, and the reflected light from the calibration mark is blocked by the harmful effects of reflected light from other parts of the panel. It is an object of the present invention to provide an optical inspection head that can perform accurate measurements without being subjected to turbulence.

Embodiments of the optical inspection head according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an optical inspection head 10 according to the present invention.
1 is an overall perspective view showing a panel picture area measuring device using a panel picture area measuring device, and reference numeral 11 in the figure is a main body housing of the panel picture area measuring device. A negative pressure source such as a blower is housed inside the main body housing 11, and a table 12 is integrally molded on the front surface thereof. The front surface of the table 12 is covered with a punching plate 13, and the plate surface of the punching plate 13 forms a surface on which a panel 14 such as a printing plate for offset printing is placed, and this placement surface faces upward toward the main body housing. It is inclined so as to gradually approach the dorsal side of 11. This inclination allows the panel 14 to be easily and smoothly placed on the punching plate 13 of the table 12.

The placed panel 14 is positioned by a positioning bar 15 at the bottom of the table 12 and positioning pins 16 on either the left or right side, and is suctioned and fixed onto the punching plate 13 of the table 12 by the operation of a negative pressure source such as a blower.

On the other hand, a pair of guide rods 17 and 18 are provided horizontally at the upper and lower front surfaces of the main body housing 11, and the horizontal movement of the optical inspection head 10 is guided by the guide rods 17 and 18. An optical inspection head 10 is mounted so as to straddle a table 12 and is reciprocated on the table 12.

The inspection head 10 has a box-shaped head casing 20 in which, as shown in principle in FIG. 2, an illumination optical system 21 and an optical detection device 22 are provided. The illumination optical system 21 includes two fluorescent lamps 2 arranged in parallel as linear illumination light sources.
It has 3.23. As shown in FIGS. 3 and 4, both fluorescent lamps 23, 23 are held near their ends by fixing holders 25, and are fixed to both bottoms of the head casing 20. The fluorescent lights 23, 23 are covered from both outer sides by masks 26, 26 fixed to the bottom wall of the head casing 20, as shown in FIG. The masks 26, 26 extend obliquely toward the panel 14 and terminate at a position near the panel surface, and an elongated rectangular window portion 28 is formed at the terminal end.
Irradiation light from the fluorescent lamps 23, 23 is irradiated through this window portion 28, and the detection area A of the panel 14 is slit exposed. At this time, the straight portion of the mask 26 is formed as a non-reflective surface 26A that absorbs the irradiated light from the fluorescent lamps 23, 23. The non-reflective surface 26A is painted black.

Further, the optical detection device 22 is housed within the head casing 20 and is fixed to the bottom surface of the head casing 20 by an L-shaped fixture 30. The optical detection device 22 has a large number of light-shielding boxes 31 arranged in a row, and an optical sensor 32 such as a photodiode as a light receiver attached to the top of each light-shielding box 31. A slit 33 is attached to the lower part of each of the slits 31 . Each light-shielding box 31 is located in the middle upper part of both fluorescent lamps 23, and guides the reflected light of the light obtained by slit-exposing the detection area of the panel 14 to the optical sensor 32. The row of light shielding boxes 31 extends in a direction parallel to the longitudinal direction of both fluorescent lamps 23.

On the other hand, a calibration mark 35 is provided on the edge portion of the panel 14 (the edge or tail portion in the case of a printing plate for offset printing) (see FIGS. 2 and 6). The calibration mark 35 is used when measuring the picture area ratio of the panel 14.
The picture area (drawing area) is the measurement standard.

A pair of light shielding plates 37, 37 are provided facing each other at a position corresponding to the calibration mark area B of the panel provided with the calibration mark 35. The light shielding plate 37 is connected to the light shielding box 31 of the optical detection device 22 as shown in FIGS. 5 and 6.
Fixed at the bottom (panel side). The light shielding plates 37 face the light shielding boxes 31 at intervals in the column direction,
It also extends and terminates near the panel 14 surface.

Next, the operation of the optical inspection head will be explained.

A panel 1 such as a printing plate for offset printing is placed on the table 12 of the picture area measuring device 22 of the panel 14.
Place 4. The mounted panel 14 is positioned by a lower positioning bar 15 and either left or right positioning pins 16, and is attracted and fixed in a predetermined position by the operation of a negative pressure source.

After the panel 14 is fixed at a predetermined position, the illumination optical system 21 is activated, and the detection area A of the panel 14 is slit-exposed with illumination light from the fluorescent lamp 23.
The reflected light from the exposed panel 14 passes through the slit 3.
3 into each light-shielding box 31.
The light is received by the optical sensor 32 and read respectively.
By reading the photos from the photosensors 32, the picture area ratio of the panel detection area A is detected individually and instantaneously by each photosensor 32.

Once the image area of a particular panel detection area A has been measured, the optical inspection head 10 is moved to measure the image area of the next detection area. Detection area A
Since the picture area is instantaneously optically measured, the optical inspection head 10 can be moved smoothly and continuously.

Furthermore, since a light shielding plate 37 is provided at the lower part of the optical measuring device 22 at a position corresponding to the calibration mark area, the reflected light from the calibration mark area B is subject to adverse effects from the surroundings. Instead, the calibration value is input to a predetermined optical sensor 32, and the calibration value can be read accurately and reliably by this optical sensor 32. In this case, since the light shielding plates 37 are arranged at intervals in the row direction of the light shielding boxes 31, the light shielding plates 37 can prevent illumination light from the two fluorescent lamps 23 arranged on both sides of the light shielding boxes 31. Never. Therefore, the calibration area B can be reliably slit exposed. In this way, the calibration value can be read accurately with a simple structure in which two light shielding plates 37 are provided facing each other on the panel 14 side of the light shielding box 31. This calibration value serves as a measurement standard when measuring the picture area (image area) of the panel 14.
Accurately measuring this value is a necessary condition for accurately measuring the pattern area ratio.

As described above, in the optical inspection head according to the present invention, light shielding plates are provided opposite to the optical detection device, and the light shielding plates are arranged so as to be located on both sides of the calibration mark area of the panel. Therefore, the reflected light from the light that exposed the calibration mark area is smoothly guided to the optical detection device without being adversely affected by the surroundings, and the calibration value can be read accurately by this optical detection device. . Since the calibration value can be read accurately, optical detection of the picture area of the panel, etc. can also be performed accurately.

Further, since the light shielding plate only needs to be provided at a position corresponding to the calibration mark area, the structure is simple and the manufacturing cost of the optical inspection head is low.

[Brief explanation of drawings]

Fig. 1 is an overall perspective view showing a panel pattern area measuring device using an optical inspection head according to the present invention, Fig. 2 is a perspective view showing the principle of the optical inspection head according to the invention, and Fig. A side sectional view partially showing the optical inspection head of the invention, FIG. 4 being a sectional view taken along the line - in FIG. 3, and FIG.
The cross-sectional view along the line in FIG. 6 shows the principle of an optical detection device integrated into an optical inspection head. DESCRIPTION OF SYMBOLS 10... Optical inspection head, 11... Main body housing, 12... Table, 13... Punching plate, 14... Panel, 20... Head casing, 2
1... Illumination optical system, 22... Optical detection device, 23...
Fluorescent lamp, 26...mask, 28...rectangular window, 31...
Light-shielding box, 32... Optical sensor, 35... Calibration mark, 37... Light-shielding plate, A... Panel detection area, B... Calibration mark area.

Claims (1)

[Claims] 1 An illumination optical system that slit-exposes a panel such as an offset printing plate placed on a table with irradiation light, and an optical detection device that receives reflected light from the exposed panel are installed in a movable and scannable head casing. In the provided optical inspection head, the illumination optical system has two linear illumination light sources arranged in parallel, and the optical detection device is arranged between the two illumination light sources and separated from the panel. This optical detection device has light-shielding boxes arranged in a row parallel to the illumination light source, and facing the light-shielding plates located at both ends of the calibration mark area of the panel. An optical inspection head characterized in that the opposing light shielding plates are arranged at intervals in the row direction of the light shielding box row so as to extend and terminate near the panel.