3, fountain solution Currently widely used on the offset printing press is the alcohol dampening system, isopropyl alcohol (industrial alcohol, IPA) is one of the fountain solution additives. Compared with the traditional water dampening version, this dampening method can greatly reduce the amount of water used, thereby avoiding the paper deformation caused by large amount of water and the excessive emulsification of the ink. And it can speed up the evaporation of water in the printing plate, greatly improving the printing effect, making the vivid color easy to achieve. However, since the gas generated after the volatilization of isopropanol has a harmful effect on the human body, it is a chemical that is harmful to the environment and the human body. Therefore, reducing the amount of isopropyl alcohol is an inevitable trend. Some countries have passed legislation to limit the use of isopropyl alcohol. In the recent production of web printing presses, isopropyl alcohol has basically been eliminated. The level of volatile organic compounds (VOCs) in factories must be reduced to a certain level to meet the environmental requirements of the system. However, as long as the amount of isopropyl alcohol is reduced by 3%, the VOC level in the air can be reduced by about 30%.
However, it is probably not easy to use isopropyl alcohol at all in the printing industry, but it is still possible to reduce from 20% to 5%-6%. The key point is to maintain the stability of water quality after removal. If tap water is used, care must be taken to be able to approach the water quality at any time. When using less dampening solvents, some adjustments must be made to the machine. The dampening roller should be turned faster, so that the thickened solvent can be diluted; the dampening roller should be turned faster, so that the thickened solvent can be diluted; the temperature of the dampening agent also needs to be reduced, and The temperature of the ink supply system must also be controlled. Although the boom of ceramic rollers has passed, replacing the rollers will undoubtedly benefit the printing of (less) alcohol. It is also possible to add 5%-10% of glycerin or glycol in the fountain solution stock. The water temperature is 7°C-10°C instead of isopropanol.
4. For the purpose of aesthetics and the protection of books, magazines and prints, the current publications and other printed materials must be covered. However, the film's harm to society is serious:
(1) The film will cause pollution of white pollution film There are two aspects: First, the film can not be rotted and degraded in the air, but also difficult to recycle, causing environmental pollution; Second, there is benzene in the processing, harmful to humans, long-term use Harm the health of workers.
(2) The coated paper cannot be recycled, destroying resources 80% of the papermaking cellulose source in China now relies on the recycling of old paper, including paper-edge paper. The volume of paper used in books and other books is very large. If we use large quantities of coated materials for the anus, then the used paper, including trimmed paper edges and paper hair, cannot be recycled. This will give the country Bring incalculable losses, which is actually destroying resources. In addition, the paper mill did not recycle because of the cutting of the paper edge and the paper fleece covered with the enamel film. People then burned the cut paper together with the uncoated paper edge. This not only caused the waste of resources, but also caused secondary environmental pollution. The consequences were serious. However, this phenomenon has not been able to attract the attention of relevant departments and publishers, design institutes and production units for more than ten years.
Second, direct plate making CTP - FQ film link 1, CTP review High-tech penetration in the field of printing and publishing performance in computer direct plate making, digital printing and color proofing three aspects, they are known as CTP technology, specifically defined as follows:
(1) Computer To Plate (offline direct platemaking technology);
(2) Computer To Press (computer directly to the printing press), namely the machine direct plate making technology;
(3) Computer To Paper/Print (direct computer to paper or print), ie direct printing technology; (4) Computer To Proof, color digital proofing.
However, people often say that CTP often refers to the first: CTPlate - off-line direct plate making technology.
The wave of computer-to-plate has set off in the global printing industry. CTP technology has become an inevitable trend in the prepress industry. It has made great progress compared to the color desktop system (DTP system) that emerged in the mid-1980s.
CTP directly outputs images and graphics to the media through a computer. This process eliminates the need for film as an intermediate link. Dedicated digital media is installed on the platesetter. The digital imposition file is sent to the computer RIP, which then sends the electronic file to the platesetter so that the electronic signal is made on the plate by means of light or a heat-sensitive machine. CTP platemaking system is a comprehensive multidisciplinary technology industry. It is a combination of precision machinery and optical technology, electronic technology, color digital image technology, computer and software technology, new type plate and material technology, automation technology and network technology. Automatic production system.
CTP technology matured in the 1990s. In 1993, since the successful development of the CTP by Donnelley and Creo Canada, the promotion and popularization has been rapid, and during this period it has reached a level of maturity and industrialization. At the drupa 1995 printing exhibition, there were 42 kinds of CTP systems on display; at the Drupa 2000 printing exhibition, more than 90 companies launched their own CTP products; and the world's printing machine manufacturers with small scales almost all have their own Digital presses exhibited. According to statistics from related agencies, 55% of the 100 large-scale printing companies in the United States have already adopted a computer-to-plate system. By the end of 2000, the total installed capacity of the world's computer-to-plate systems had reached 12,150 units. There are more than 100 computer-to-plate systems in China and are mostly used in newspaper industry systems.
In addition to the good plate-making performance and the elimination of the advantages of the film process, the CTP system has also expanded its technical application. At present, the direct plate-making machine on the market can meet the requirements of various situations such as large-format, small-format printing size, single- and dual-color printing, four-color printing, newspaper printing, and commercial printing. Therefore, it is very flexible to use.
In recent years, the development and improvement of CTP plates has also been rapid. The significant decline in the price of CTP equipment within five years has promoted the rise and development of the market. At present, 8 boot has dropped from the previous 400,000 US dollars to 15 million US dollars, the rate of decline is 37. 5% -50%.
2. Platemaking equipment At present, CTP platesetters are generally divided into four categories: inner drum, outer drum, flat plate, and curve. Among these four types, the most used are the inner drum and the outer drum type; the flat panel type is mainly used for large format plates such as newspapers; the curve type is rarely used. In these forms, the external drum gradually shows the mainstream trend.
The source of the platemaking machine includes: a gas laser (argon ion excitation 488 nm, power about 20mw); a solid-state laser (FD YAG 532nm, 100mw or more); a semiconductor laser (LD, semiconductor laser infrared semiconductor laser has the advantages of low power, long life. )
The development process of the laser used by CTP is: YAG (1064nm) infrared laser → 830nm diode laser → 533nm frequency YAG green laser → 410nm visible violet laser. The laser structure has become simpler and the performance has been continuously improved, while the price has dropped significantly.
Visible light CTP is mainly the following: purple light (shortest wavelength of 400-410nm), blue laser (argon ion laser, belong to visible light, wavelength of 514nm), green laser (533nmYAG frequency doubled laser) and red laser (wavelength is 650nm ), while the thermal plate CTP previously used infrared lasers.
When using the CTP system, it is necessary to first pay attention to the interface technology with the front-end system, that is, the data exchange technology between the color prepress processing systems, and the improvement of the data and technology of the back-end equipment. For large-capacity files, data exchange speed and data speed are critical; secondly, users are required to establish a new set of electronic file management systems to improve data preservation and retrieval technologies; then, color management technologies and RIP technologies The requirements are also very important. Large-capacity files require RIP's powerful processing capabilities to achieve a high level of work efficiency. The problem of consistency in proofing and output is the need for the participation of color management techniques.
3. Plates In the global printing industry, the competition for prepress CTP technology has gradually focused on Thermal Plate IR Laser CTP and Silver Plater CTP. Competitively.
The difference in equipment price between the two major categories of CTP is not significant at present. With the rapid reduction of the cost of the purple laser, the manufacturers who can supply the plate will also increase. It is estimated that the CTP price of the violet laser and other visible lasers will be lower than that of the thermal CTP. At present, the consumption of thermal plates accounts for 4% of the total volume of all kinds of plates (including traditional PS plates), while the share of violet lasers and other visible plates is about 1%. With the rapid growth of the violet laser CTP, its plate share will also grow rapidly.
If the speed of the engraving is required, the violet laser CTP can be selected; however, if it is required to completely process the plate under natural light conditions, the thermal CTP is most suitable. As for the print capacity, the maximum print capacity of unbaked thermal plates is up to 150,000 marks; the print volume of the plate after baking is very high, but the oven used for baking plates consumes a lot of power. The violet laser CTP does not require baking equipment. It is a clean, fast, and inexpensive system. The cost of installation and service is also 20%-25% higher than thermal plate paper.
Thermal plates and visible plates have their own advantages. Each has a specific application market. However, from the perspective of comprehensive factors (cost, quality, speed, and other major parameters), the development prospects of violet lasers will be better than thermal plates. Some experts predict that: By 2002, visible light CTP will be more popular than thermal CTP. (Xia Liying) ("Chinese Printing")