Application of photoelectric technology in the hot

  • Detail

Application of photoelectric technology in packaging and printing

with the introduction of a series of new technologies such as optical and electronic technology, packaging and printing technology and equipment are becoming more and more advanced. Photoelectric technology plays an important role in modern printing and packaging technology, including automatic control of packaging machine, electronic plate making and color separation, etc. In order to discuss the application of photoelectric technology in the field of printing and packaging, this paper will discuss the photoelectric detection technology in the process of packaging control and the laser technology in printing plate making

I. photoelectric detection technology in the packaging process

photoelectric detection is mainly measured by photoelectric sensors. The working principle of the photoelectric sensor is: the light source production focuses on the hot, key and difficult issues of science and technology and industry in many fields, such as copper alloy, aluminum alloy, magnesium alloy, lead alloy, zinc alloy, titanium alloy, rare refractory metal materials and surface treatment. The luminous flux is generated, and the parameters of luminous flux (such as the cross-sectional area of radiant energy flow, spectral composition and luminous intensity, etc.) are controlled by the measured object, Then it is received by photoelectric devices and then transformed into changes in electrical parameters for measurement. Different light sources can be used in different working environments, such as incandescent lamps, lasers, light-emitting diodes, etc. Sometimes the controlled object itself is the signal source, such as the mark line on the packaging bag

due to the weak signal detected directly and the lack of stability, the amplification and shaping circuit is often added to the control circuit to improve the practical operation ability of the system. Measuring institutions include indicating instruments, alarms, digital displays and product sorting devices, which display the relevant measured values of products or automatically classify products. Usually, in order to automatically adjust the production process so that the controlled quantity remains unchanged or changes according to some laws (such as realizing the automatic adjustment of the cutting position of packaging bags), a feedback circuit needs to be added to the circuit

photoelectric detection system has the advantages of simple structure, long detection distance, high precision, fast response speed, long service life and so on. It has its unique advantages in pattern recognition. It can realize non-contact detection without force and torque acting on the measured object. Even if the measured object has a large impact, it will not damage the detection instrument. Similarly, for some products with high requirements for packaging production process, such as food and drugs, their non-contact characteristics can be used for measurement

photoelectric detection circuit is composed of electronic components or integrated circuits, with low cost and high sensitivity, which can realize rapid measurement, objectivity of indicated value, etc., and is easy to automate. With the development of computer technology and mechanical industry, it can realize the combination of light, machine and electricity, calculate and process data, check, logical judgment, storage, etc., so as to realize the adjustable and synchronous supply of precision in the packaging process

to illustrate the problem, here is an example of position detection and positioning in the process of automatic packaging control:

due to the continuous reduction of the drum radius during the packaging operation, the tension on the packaging paper changes, the friction between the paper feeding roller and the packaging paper, such as personnel problems, capital problems, and the friction coefficient fluctuates under the influence of environmental temperature and humidity, plus the trademark printing error and the differences in paper feeding, longitudinal sealing, cutting, etc, Make the actual tangent of the knife roll deviate from the specified position. Although the error each time is very small, due to the long-term accumulation of high-speed operation of the machine, it will lead to serious deviation of the tangent, reduce the packaging quality, and even cause waste products. Therefore, it is necessary to add automatic photoelectric positioning detection and control equipment to the system

the photoelectric detection and positioning system uses photoelectric tracking to detect the positioning color code on the packaging paper. By comparing the error between the paper feeding speed and the transverse sealing cutting speed, it outputs the corresponding control signal to promote the automatic positioning of the actuator or error compensation. In order to detect reliably, it is required that there is a significant difference between the positioning color code and the background color of the packaging paper. The greater the contrast, the more sensitive the detection is. The color code requires bright color, uniform printing ink and a certain area. Generally, the color code is rectangular, and the length and width should have an appropriate proportion. According to different packaging materials, photoelectric detection is divided into transmission type and reflection type. The transmission type is used for the detection of transparent materials, and the packaging materials pass between the transmitting head and the reflecting head. In this way, even if the packaging materials bounce during the feeding process, it will not affect the detection sensitivity, and it is not easy to be disturbed by the ambient light. The transmitting head and the reflecting head of the reflective type are in the same direction, and it is required that the condensing beam form a focus on the packaging material or the reflecting plate, so the packaging material is not allowed to have a large jump when passing the testing part. According to different packaging forms and packaging requirements, there are different photoelectric detection and positioning devices used in packaging machines for feeding, bag making, sealing and cutting

Second, laser technology in printing plate making

laser is a new discipline and high-tech. since its birth in the early 1960s, it has been valued and developed rapidly all over the world. As a result, the application scope of laser has been continuously expanded, and many corresponding fields have undergone profound changes. The printing industry around the world, like other industries, is also actively adopting this new technology. Laser is used in electronic plate making and color separation, laser Phototypesetting, holographic printing technology and so on, and greatly optimizes the printing system. Limited by space, this paper only discusses the application of laser in plate making. The printing plate is an indispensable part of the printing process. It is the medium that transfers the ink to the substrate. The quality of the printing plate is directly related to the quality of the print. 8. Result comparison: multiple experimental characteristic curves can be superimposed, reproduced, amplified and displayed with different colors, and a group of test samples can be analyzed and compared; Implantable peek has excellent biocompatibility. The industry has been working hard to improve the plate making process, in order to make the printing plate fastest and best, reduce labor intensity and reduce the plate making cost at the same time. In the early stage, the production of gravure, embossing and offset printing plates mainly depends on manual, mechanical, chemical corrosion, electric photography technology, etc., but these methods have defects such as lack of operational stability and long plate making time. These problems have been solved since the birth of laser. Using the high intensity, high coherence and monochromaticity of laser, printing plates can be produced quickly and reliably

laser engraving plate is to shoot the focused laser beam to the plate, melt the specified range of the plate, and then remove the unwanted parts to produce convex and concave images. The shape, size and size of the image can be controlled by electronic modulation. Generally speaking, when the power density of the laser reaches 10 low/cm, the plate making materials (including ceramics) must be melted or vaporized. After the medium intensity laser beam is focused by the lens, the power density value obtained at the focus is far greater than the above value, so the laser is more suitable for engraving plates. Because of its monochromaticity, high energy and good coherence, laser has shown strong advantages in engraving and plate making, especially the development and application of modern violet laser technology, which makes the plate making more perfect. Laser has high intensity, which can not only melt and etch non-metallic materials (such as imaging film, photosensitive resin plate and plastic plate), but also melt metal materials (nickel, lead, steel, chromium and other plates). Even ceramic rollers with high fire resistance can be etched. Compared with other methods, the etching range is much wider. Laser plate making is fast and of good quality. Generally, the time to carve a split is about 3min. If the purple laser technology with shorter wavelength is adopted, the time will be shorter, and the resolution can be improved to ensure the point quality. Because the laser has good coherence and concentrated energy, it has high carving efficiency and less total energy consumption. Laser plate making is not perfect. The problem lies in the poor effect of laser direct engraving metal. Because the inking holes etched by laser are not smooth and have burrs, and the metal surface has a large reflection effect on the laser, only high-power lasers can be used for engraving. The general solution to this problem is to put a resin or plastic sleeve on the outside of the metal drum, and the laser does not directly engrave on the metal plate. The laser technology in modern plate making industry is mainly manifested in CTP technology and violet laser technology

III. conclusion

photoelectric detection technology and laser technology can be attributed to the category of photoelectric technology. The emergence and development of modern new technology and equipment is no longer the development of a single discipline, but the result of mutual penetration and complementarity of multiple disciplines. Photoelectric technology used in printing and packaging is a comprehensive technology developed on the basis of information, control and system theory based on optics, electronic technology, atomic physics, quantum mechanics and other disciplines, and their development will also bring good economic and social benefits to the printing and packaging industry

Copyright © 2011 JIN SHI