Laser technology to promote the modernization of printing

【Abstract】This paper focuses on the important role of laser modulation scanning technology in modern printing. It is introduced from computer direct production and digital printing respectively, so as to further deepen the understanding of digital printing.
[Keywords] optical modulators, digital printing, data processing Lasers are emerging disciplines based on optics, atomic physics, and electronics. Since the first lasers were born in the world in the 1960s, laser and laser technologies have become Important high technology. Its theory and application have revolutionized many technology fields. The printing industry has entered the era of "light" and "electricity." This article only discusses the impact of laser on the development of printing modernization and discusses the important position and application of laser technology in modern printing technology.
First, the laser modulation laser can be used as a tool for transmitting information. The process of loading the information (digitalized image and text) to be transmitted to the laser radiation is called laser modulation. Because the laser plays a role of “carrying” information, it is called It is a carrier. Commonly used in print printing are electro-optic modulators and acousto-optic modulators. In practical applications, there are mostly acousto-optic modulators. The acousto-optic modulator consists of an acousto-optic medium, an electro-acoustic transducer, a sound-absorbing device, and a driving power source.
The acousto-optic medium used for acousto-optic modulators in printing equipment is the lead molybdate (PbMoO4) crystal. The electro-acoustic transducer piezoelectric crystal is lithium niobate (LiNbO3), which utilizes the reverse piezoelectric effect to generate an ultrasonic field under the action of an applied electric field to form an ultrasonic field and to convert the modulated electrical signal into an acoustic signal. The operation of the laser is driven by the modulation power supply. When the laser passes through the acousto-optic medium, Bragg diffraction occurs due to the interaction between the light and the acoustic field, and the first-order diffracted light is output as the output. When the amplitude of the acoustic wave changes with the modulation signal, the intensity of the diffracted light will change accordingly. The output light is periodically modulated light.
Here, the modulator also serves as an electro-optic switching device in the optical path system, that is, converts the electrical information signal of the graphic and text output by the computer into an optical signal.
2. Modulators in computer-to-plate (CTP) technology Modulators have become indispensable for the transmission of graphic information in printing. Early applications and laser engraving machines, electronic scanning color separation machines, laser photosetters, and laser printers And other equipment. With the development of printing technology, the newly emerging computer-to-plate (CTP) technology, also known as non-film-making, is a high-tech that has been rapidly developed in the 1990s. It is a digitized graphic message processed by the computer and recorded directly on the plate by laser modulation scanning. Therefore, the plate making equipment is composed of a computer prepress processing system and a laser plate making machine. Dozens of models have been introduced. The principle is almost the same, and computer-controlled laser beam modulation scan plate imaging technology is used.
The electronic computer delivers the processed digitized graphic information to the electro-acoustic transducer of the acousto-optic modulator. At this point, the laser beam is modulated by the acousto-optic modulator, and its first-order diffracted light is directed to the multi-faceted rotating mirror, and then scanned and exposed by the Fθ objective lens on the printing plate to be directly made into an offset printing plate. The plates produced have the advantages of good quality and high speed.
Figure 2 shows the Laserite 100 FLUV laser platemaking system consisting of a computer, an argon ion (Ar+) laser, an acousto-optic modulator, a multi-faceted rotating mirror, and an Fθ objective lens.
The commonly used lasers in the CTPlate computer-to-plate technology are argon ion lasers (488 nm and 514.5 nm), ytterbium-doped yttrium aluminum garnet lasers (1,06 μm), and HeNe lasers (632.8 μm). Among them, air-cooled argon ion lasers are mostly used.
It can be seen that the computer-to-plate technology can omit the intermediate process from the original to the printing plate in the traditional printing. Suitable for light and newspaper printing in fast, low-volume production. Further use in formal printing becomes its future development direction. It plays an important role in promoting the modernization of printing.
3. The digital printing of modulators in digital printing technology is based on a relatively sophisticated computer data processing technology. The combination of laser modulation and scanning imaging technology and high-tech photosensitive materials and new printing inks combine these high-tech technologies to realize the entire printing process. Computer-controlled digital integration. It is a modern printing system with a completely different concept and process than traditional printing.
Among them, laser modulation scanning imaging technology is mainly used in the mechanism version. The color separation data signal (monochrome pixel digital signal) is input to the laser controller during the plate making, so that the emission synchronous monochrome laser beam is converted into the screen data by the RIP. The stencil of the printing plate is subjected to laser modulation and scanning imaging, and the photosensitive material on the roller is sensitized to form a pattern capable of adsorbing ink or toner, and the printing can be printed. The principle of different plate-making with the printing plate photosensitive material can be roughly divided into two categories: one is the laser electrostatic imaging type. Such as Indigo E-print1000 and Omnius digital presses. The other type is a silicon-based rubber type offset type. Such as Heidelberger's Quickmaster DI (Rapid) and KBA and Safran's 74 Karat digital presses.
The digital printing equipments all have substantially the same laser modulation scanning imaging system. Argon ion lasers and semiconductor lasers are commonly used in the system lasers, and the acousto-optic crystals of the acousto-optic modulators are lead molybdenum (PbMoO4) electro-acoustic devices. The transistor is lithium niobate (LiNbO3). The modulator is still an important and indispensable core device for transferring graphic information.
IV. Conclusion Digital printing is an important symbol of modern printing. Personalize on-demand printing. That is, the realization of dynamic or variable image printing will have a major impact on the traditional printing process. Another revolution in traditional printing, it involves a variety of high-tech such as computer information processing technology, laser technology, materials science and so on. They are a whole organic combination. Therefore, laser technology should also be one of the indispensable high technologies for promoting modern printing.
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