The hottest silver salt violet laser direct plate

2022-08-12
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Silver salt violet laser direct plate making

laser and violet laser

as we all know, the commonly referred to light generally refers to visible light, that is, electromagnetic radiation with a wavelength between 380nm and 780nm. It can cause vision to human eyes, and the colors it presents are blue (400 ~ 500nm), green (500 ~ 600nm) and red (600 ~ 700nm). If it is subdivided, it is also red, orange, yellow, green, cyan, blue and violet. These visible lights are only universal experimental machines with medium wavelengths of electromagnetic radiation. The vertical manual spring tension experimental machine is a simple and narrow part of the tension machine, and the rest is just invisible to people's vision, as shown in Figure 1. Normal align=ce UHD TV is famous for its ultra-high definition, precise details, gorgeous color and high illumination. Nter>

normal align=center> Figure 1. The discovery of electromagnetic radiation area

laser makes the light source have the characteristics of single wavelength and energy concentration. In some photophysical and photochemical reactions, it plays a role that continuous wavelength light cannot achieve. From the development process of lasers, from gas to solid, from long to short wavelength, from large volume to miniaturization, the application fields are more and more extensive. CTP technology is the crystallization of laser technology and digital technology. From the perspective of the laser it uses, it is a transition from long wavelength to short wavelength. Specifically, it is YAG (1064nm) infrared laser 830nm near infrared laser diode → 650nm red laser diode - 532nm frequency doubled YAG green laser and 488nm argon ion gas laser → 405nm violet laser diode. The wavelength region of 400 ~ 410nm is the purple laser region with the shortest visible light range. Therefore, lasers emitting wavelengths of 400, 405 and 410nm are called purple lasers

due to the greater difficulty in developing lasers with shorter wavelengths, it was not until 1996 that the 410nm InGaN crystal violet laser diode was developed by nichio company in Japan. Since then, the purple laser diode studied by Nichia in 1999 has a service life of more than 10000 hours, and it was widely used in DVD and DVR equipment. In recent years, due to the further improvement of the performance and the reduction of the price of violet laser diodes, a new path has been opened up for the new generation of CTP technology, which has become a high-profile violet laser CTP technology

purple laser CTP technology

purple laser CTP technology first appeared at drupa 2000 Expo. Once it was displayed, it was favored by visitors, because it has very attractive characteristics:

① by the length of dry Purple laser wave, small scattering, fast imaging speed, using smaller rotating mirror and motor in CTP plate making machine, it improves the speed of rotating mirror, shortens the exposure time, and can be quickly exposed on large-scale printing plate, Improve production efficiency. In addition, because of its wave length, it can focus to get a smaller laser beam, improve the scanning accuracy, improve the line definition and resolution, so as to improve the printing quality

② the laser can be switched on and off directly by using purple laser without using electronic modulator. It only works when scanning and imaging on the printing plate. Lasers such as YAG are switched on and off synchronously with the plate making machine, and the modulator controls the passing or blocking of the laser during imaging. This is also the main reason why violet laser has a long life. The 5MW diode produced by Nichia company in Japan has a service life of 10000 hours

③ the stability of purple laser diode is good. It can reach a stable state for exposure and plate making after about 3 minutes after starting up, while the plate making machine using YAG laser needs to be preheated for more than 20 minutes after starting up, so that the output energy of laser light source can reach a stable state. In addition:

A. The Purple laser printing plate can be used under the bright yellow safety light, which is similar to the environment used by traditional PS plate or thermal CTP plate

b. violet laser diode is simpler and cheaper than other solid-state lasers and gas lasers. In addition, it can also be used in DVD and DVR equipment, which has great market potential. This is also the reason why violet laser diode is rapidly mass produced and the cost is greatly reduced

due to the above advantages of violet laser, violet laser CTP technology has developed rapidly and received attention in the industry. In recent years, many equipment manufacturers have invested in the development and promotion of violet laser CTP technology, such as Agfa, Barco, ECRM, Esther grod, highwater, Krause, Fuji, lighotech sack, purup eskofot, press technologies, Heidelberg and other companies. Hundreds of violet laser CTP devices have been sold worldwide. The Institute of physical and chemical technology of the Chinese Academy of Sciences arrived in July 2002 and installed two planum 2218 lithographic scanning 4-open plate making machines from Krouse company, which use purple laser (405urn) and green laser (532nm) respectively, and the resolution can be 1270dpi and 2540dpi. At present, the operation is normal, which creates good conditions for us to study new violet laser plates

normal> silver salt purple laser CTP plate

at present, the purple laser diode power provided by Nichia, tuioptics and other companies engaged in laser production is 5MW, and then 10 ~ 30MW laser diodes will be gradually introduced. Because the power is not as large as other lasers, the sensitivity of the corresponding plate is required to be higher due to the adoption of single-chip computer control

in recent years, many plate manufacturers have invested in the research and development of CTP plates suitable for violet laser, such as Agfa, Fuji, Mitsubishi Chemical, etc. It can be said that the silver salt diffusion C3, electronic tensile testing machine selection index TP plate is currently just suitable for low-power violet lasers, such as Agfa's lithostar ultra lap-v silver salt plate. Because its sensitivity is at J/cm2 level, it only needs 5% - 10% of the energy of 5MW laser diode, which is inferior to other non silver salt CTP plates at present, because other types of plates must be made under the condition of high energy

the structure and principle of silver salt diffusion plate have been introduced by the author, and they are only briefly described here. As shown in Figure 2, the plate is coated with an ultra-thin layer of physical developing core on the sanded aluminum base plate in turn as an image receiving layer and a laser sensitive silver halide photosensitive layer. After laser scanning and exposure, through 30 seconds of development and water washing, the non graphic area is partially washed away to expose the hydrophilic aluminum base, while the graphic area is closely stacked by the diffusion transferred silver particles into the lipophilic image area, and the plate shows an obvious boundary between the ink and the hydrophilic area. Normal align=center>

normal>normal align=center> Figure 2 Schematic diagram of silver salt CTP plate structure and processing process

at present, we are developing compact laser CTP plate, which has met the requirements of direct manufacturing Copyright (krause-platinum 2218) equipped with 5MW violet laser. The spectral photosensitive range of this plate is shown in Figure 3. Fig. 4 and Fig. 5 are electron microscope photos of silver halide microcrystalline structure and atomic force microscope (AFM) photos of nm physical developing nucleus, respectively. Normal align=center>

normal align=center> Figure 3 the spectral sensitivity range of the purple laser silver salt CTP plate developed (the center is 400nm) normal align=center>

normal align=center> Figure 4 silver salt CTP plate silver halide microcrystalline electron microscope photo normal align=center>

normal align=center> Figure 5 AFM photo of nano physical developing nucleus

because the silver salt photosensitive material has high sensitivity, high quality and high fidelity and other characteristics, It has a wide range of applications. The history of more than 100 years, figure 5, proves its vitality. Although the development of digital technology and other chemical materials has brought challenges to the silver halide system, there are still no materials and technologies that can completely replace it. In a long period of time in the future, with the combination of digital technology, silver salt photosensitive materials will still show strong vitality

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