JPS63118603A - Ink film thickness measuring instrument - Google Patents

Abstract

PURPOSE:To minimize the influence of the unevenness of the ink surface of a substrate by measuring the spread of an image or the shape of a brightness distribution, etc., with data from a detector and calculating the thickness of an ink film from the measured value. CONSTITUTION:This device consists of a laser light emission device 2, a lens 4, a detector 5, and a computing element 6 and the detector 5 measures the spread of plural projection light beams. At this time, glass which has a refractive index distribution periodically in two directions is regarded as a flat plate 9 which has many small lenses 8 and many convergent light beams 11 obtained by projecting parallel light 10 thereupon are projected on the ink film. Then, the spread of plural projection light beams on the ink surface is measured by a detector 5 and analyzed by the computing element 6. Consequently, as the spread of images becomes larger and larger, relative dispersion becomes lower and lower and the gradient of a graph increases, so that an analytical value of good quality is obtained. Therefore, even if the substrate of the ink surface has unevenness, its influence is minimized, so a decrease in measurement accuracy is eliminated and the ink film thickness is easily measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ink film thickness measuring device that uses laser light to measure the ink film thickness in a printing press.

[Prior art]

Previously, the applicant has invented an ink film thickness measuring device that can measure the ink film thickness in a printing press, thereby improving the performance of the printing machine and saving labor.
16149.2). As shown in FIG.
A laser beam 3 is applied from a laser beam emitting device 2 to the ink surface of the roller 1, an image generated by the laser beam is received by a detector 5, and the image is spread based on the data sent from the detector 5. , the shape of the brightness distribution, or the brightness gradient, and based on the measured values, the arithmetic unit 6 calculates the ink film thickness on the roller surface.

[Problem that the invention seeks to solve]

However, in the conventional method, only one point of light is projected onto the ink surface. Therefore, as shown in FIG.
When the substrate 7 is flat and mirror-like, the spread of light in the ink film layer will faithfully reflect the film thickness, but as shown in Figure 3, if the substrate 7 has irregularities such as fine scratches, However, there was a problem in that the direction of light reflection on the substrate surface varied, creating an element of uncertainty between the ink film thickness and the spread of the projected light, resulting in a decrease in measurement accuracy.

This invention was devised to solve the above problems, and is an ink that can minimize the effect of unevenness on the substrate on the ink surface and prevent a decrease in measurement accuracy. The purpose is to provide a film thickness measuring device.

[Means for solving problems]

The ink film thickness measuring device of the present invention includes a laser beam emitting device on a roller surface, a detector that receives an image generated on the ink surface by the laser beam, and data sent from the detector to measure the spread or brightness of the image. The detector is characterized by comprising a calculator that measures the shape of the distribution or the brightness gradient and calculates the ink film thickness based on the value, and the detector measures the spread of a plurality of projected lights.

〔Example〕

The present invention will be explained below based on embodiments shown in the drawings.

The ink film thickness measuring device of the present invention basically consists of the laser beam emitting device 2, the lens 4, the detector 5, and the arithmetic unit 6 as described in the conventional example. The detector 5 measures the spread of a plurality of projected lights.

■First Example As shown in Fig. 5, a glass having a periodic refractive index distribution in two directions is regarded as a flat plate (microlens plate) 9 with many small lenses (microlenses) 8, and parallel light is 10, a large number of focused lights 11 are obtained.

This focused light 11 is projected onto the ink film, and the spread of the plurality of projected lights generated on the ink surface is measured by a detector and analyzed by a computing unit.

(2) Second Embodiment As shown in FIG. 6, a large number of self-hock lenses 12 are arranged, and parallel light 10 is projected onto them to obtain a large number of focused lights 11. Note that FIG. 7 shows projection patterns of the first embodiment and the second embodiment.

(3) Third Embodiment By projecting a large number of separated lights, the same effects as in the first and second embodiments can be obtained even with line-shaped projection light. In FIG. 8, a plurality of semi-cylindrical lenses 13 arranged in parallel are used to project a large number of line-shaped projection lights. FIG. 9 shows the projection pattern and brightness distribution.

■Fourth Embodiment As shown in FIG. Second. This provides the same effect as the third embodiment. As shown in FIG. 11, the light passing through the collimator lens 14 shows a plurality of roll-shaped patterns.

■Experimental results Fig. 13 to Fig. 15 are for each position a, b shown in Fig. 12,
It shows the spread of the image at point c, where 14 is a collimator lens, 11 is a focused beam, and 16 is a focal point. Also, Figure 16~
FIG. 17 is a graph showing the measurement results of each of the above-mentioned ia, b, and c, where the vertical axis is the number of pixels and the horizontal axis is the ink thickness. As is clear from these figures and graphs, the larger the spread of the image, the lower the relative dispersion, and the lower the relative dispersion, the higher the slope of the graph, making it possible to obtain high-quality analytical values.

〔Effect of the invention〕

This invention has the above-mentioned configuration. According to this invention, even if there are irregularities on the substrate on the ink surface, the influence can be minimized, preventing a decrease in measurement accuracy, and moreover, it is possible to easily adjust the ink film thickness. It can be measured.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a conventional example, Figs. 2 to 4 are cross-sectional views showing the spread of the projected light applied to the substrate on the ink surface, Fig. 5 is a perspective view showing the first embodiment, and Fig. 6 is a perspective view showing the second embodiment; FIG. 7 is a diagram showing the projection pattern of FIGS. 5 and 6;
FIG. 8 is a perspective view showing the third embodiment, FIG. 9 is a diagram showing the projection pattern and brightness distribution of FIG. 8, FIG. 10 is a perspective view showing the fourth embodiment, and FIG. Figure 12 is a conceptual diagram showing focused light by a collimator lens, and Figures 13 to 15 show the spread of the image at each position a, b, and c in Figure 12. The pattern diagrams shown in FIGS. 16 to 18 are graphs showing the measurement results of images at positions a, b, and c in FIG. 12, respectively. 1...Roller, 2...Laser light emitting device, 3...Laser light, 4...Lens, 5...Detector, 6... Arithmetic unit, 7
...Substrate, 8...Microlens, 9...Microlens plate, 10...
...Parallel light, 11...Focused light, 12...
・Self-hook lens, 13...Lens, 14・
...Collimator lens, 15... Light 16
······focus. Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 + L1 Illll Figure 12 Figure 16 Figure 17 Figure 18

Claims (1)

[Claims] a laser beam emitting device that shines a laser beam on the roller surface;
A detector receives the image formed on the ink surface by the laser beam, and the data sent from the detector measures the spread of the image, the shape of the brightness distribution, or the brightness gradient, and the ink film thickness is determined based on the measured value. It consists of a computing unit that calculates
An ink film thickness measuring device, wherein the detector measures the spread of a plurality of projected lights.