CTP technology enters the era of environmental protection

At the drupa printing conference in 2008, the MediaPrint Group, an Austrian newspaper printing company, signed a one-time agreement with 11 Agfa's NJStar platesetters and years of use contracts. Maybe this order is just a common one in many big orders in this drupa conference, but it is of great significance to the application and development of CTP technology. The company became the first newspaper printing factory in the world to use a CTP-free system, and it used a violet-free CTP system. The continuous successful application of the violet laser with thermal characteristics and the thermal-free CTP system is undoubtedly a message to us: The application of CTP technology is entering the era of environmental protection.

Treatment-free plate is an environmentally friendly CTP plate. The traditional concept of CTP plate, whether it is the thermal or violet laser plate exposure on the plate making machine must undergo chemical development and water rinsing and other processes, consume a lot of chemical developer and water, free processing CTP plate can To eliminate or simplify this process, there is only a very small amount of waste liquid, or no waste liquid is generated at all. The CTP plate making process is further simplified, and it can be said that the exempt plate processing helps us achieve the prepress green production. The emergence of violet laser-free processing plates breaks the long-standing claim that only the thermal technology can achieve free handling. Now almost all users of thermal and violet laser technology can switch their CTP production to environmentally-friendly, process-free CTP plate production, and each technology has multiple media options.
In fact, since the CTP equipment, plate material manufacturers have not interrupted the development and research of the CTP plate material, and the environment-friendly free-handling plate is also the focus of development of each plate material manufacturer. At present, there are many free-handling plates that can be seen. For ease of understanding, according to the characteristics of the plates, we can classify them as follows:

1. Completely free processing of plates

Completely free processing of plates is the plate that can be directly printed on the machine after being imaged on the platesetter, and there will be no other subsequent processing on the printing machine. If you use a completely free processing plate, with advanced waterless printing presses, there will be no waste liquid generated, and you can achieve true green printing. However, the equipment and technical threshold of this printing mode is too high, and it has no reference value for the printing users of the existing equipment.

Thermal ablation and thermally induced polar transitions are two types of technology that are completely free of plate processing. The thermal ablation technique uses the thermal energy of the infrared laser to ablate the surface coating of the plate, exposing the aluminum plate, exposing the graphic part without being ablated by the laser, thus forming a graphic and non-graphic image. section. The advantage of the thermal ablation plate is that it is completely free of processing, and the development is completed when the image is exposed, and subsequent development is not required. Disadvantages are the dust generated by the coating during the ablation process of the plate. It is necessary to add a special suction device to the plate making machine. This is not a type of plate used for the thermal plate directly at present. In addition, because of the high laser energy requirements, the platemaking speed will be much lower.

Thermal polarity conversion technology utilizes the surface coating of the plate material to undergo a polar transition under the thermal energy of the infrared laser. The hydrophilic and lipophilic properties of the thermal coating surface are changed. Such a printing plate can be directly processed without any other post-treatment. Printing on the machine. However, due to problems such as production costs and print suitability, this plate has not been produced commercially in large quantities.

Due to the technical limitations of plate-free processing, there is currently only a small amount of trial production, and due to the low sensitivity of the plate, even if a high-power laser is used, the production efficiency is still low, and it can only be used for production speed in the future. Less demanding commercial printing.

2. Machine-processed plate free of processing

The so-called on-machine development is the exposure of the plate to the platemaking machine. The plate is developed on the printing press. The plate is developed by the wetting effect of the fountain solution, and the non-graphic film is removed. This on-press developed media was first developed for direct imaging (DI) printers and was popular around 2000, because direct imaging presses required a laser imaging device for each color drum, laser cost, and Subsequent maintenance costs are very high. From now on, direct presses have gradually been replaced by digital presses. Based on the thermal-based on-machine development of the CTP plate without processing, there are also some users, purple laser in-vivo development plate because of the higher requirements of the purple laser energy, not for the existing purple laser CTP users The available media will take some time for its application and promotion.

The advantage of on-machine development CTP plates is that they do not require chemical development, and there is no waste in prepress plates. The disadvantage is that due to the development on the printing press, the printing operator's identification and proofreading of the layout content and the control of the platemaking quality cannot be accurately performed. On the contrary, it is apt to cause an operational error, causing waste of time and materials; in the course of on-press development, the printing plate Non-graphic part of the film into the fountain solution circulation system, will bring printing problems. On-machine developing plates are designed for short-run printing, so the printing rate is relatively low, generally about 50,000.

In-machine development-free handling of CTP plates is limited in newspaper printing because the existing plate-centered bending plate punches cannot confirm the positioning marks on the plate surface and cannot accurately perform the bending plate punching process. The development of printing plates on the printing presses can easily cause web breaks, and it is impossible to identify and confirm the layout contents before printing, and it is also a significant disadvantage in newspaper printing.

3. Chemical-free processing media

The chemical-free processing plate is subjected to development processing after being imaged on the plate-making machine before being printed on the machine. This process does not use a chemical developer, cleansing with clear water or development of the printing plate in the process of gluing the printing plate. Compared to the traditional concept of CTP plate, chemical-free plate cleaning saves the chemical developer, without the need for complex and expensive developing machines, and requires only simple processing to obtain the same machine-printable plate as the traditional CTP plate. . The chemical-free processing of plates will still produce waste, but the amount of waste generated is only 5-10% of the traditional CTP plates. The printing machine operator got the contrast of the upper machine plate obviously, the picture and text are clear and distinct, there is no difference with the traditional CTP plate material, the printing India rate is also very high, generally more than 100,000 printing.

Agfa's hot-melt technology-based Azura (Azura) is a typical example of a chemical-free processing media. The surface of the green star plate is composed of thermoplastic particles, and the thermoplastic particles are bonded together by thermal fusion during the exposure and imaging process and are firmly bonded with the aluminum plate to form a graphic part. The printing plate is required to protect the printing plate before the printing machine, and the protective glue softens the unexposed thermoplastic particles and breaks off from the surface of the printing plate under the external force of the brush, so that the printing plate is completed during the gluing process. The development. The glue used is non-toxic and harmless, and the amount is extremely low. 20 liters of glue can handle 300 square meters of printing plates. At present, this plate has been widely used in commercial CTP, but due to the problem of exposure speed, it cannot be used for newspaper CTP.

Agfa has recently launched a violet laser chemical-free processing plate. The development process of this plate is similar to that of the Green Star version, but it is necessary to pre-heat the plate prior to over-protecting the glue, which can significantly increase the plate resistance. India. The advantages of this plate are high sensitivity and high printing rate, which is very suitable for newspaper CTP output and printing.

All of the above free-handling plates can provide printing users with opportunities for green plate production. However, as the actual production printing plate material, its most important feature is to have excellent printing performance and strong adaptability to fountain solution. High print-to-print rate; followed by simple quality control of platemaking, convenient printing operations, and best use of plates, no special adjustments for platesetters and printers; and the price of plates. The cost of comprehensive use of environmentally friendly plates is preferably no higher than the cost of using traditional plates. From the previous introduction, we can see that the chemical-free processing media has outstanding advantages in terms of printing performance and operability in printing. In terms of comprehensive use cost, the three technologies are equivalent, because the cost of developer and developing equipment is saved, and the cost of handling the plate is not higher than the cost of using traditional plates. In some cases, strict requirements are imposed on waste discharge. In countries and regions, the cost-free processing of plate materials will be lower than the cost of traditional plate materials. The actual data show that in 2007, the chemical-free processing media accounted for about 80% of the total application-free plate market applications.

Ever since the United Nations Conference on Environment and Development in 1992, countries and regions around the world have almost coordinated the relationship between the environment and development and achieved sustainable development as an important agenda and strategy. In China's recent "Eleventh Five-Year Plan", the quantitative indicators for "energy saving and emission reduction" tasks and measures are more clearly defined. The purpose is to pursue less resource consumption, lower environmental pollution, greater economic and social benefits, and promote green Production methods and civilized consumption advocate low-input, high-output, less-polluted, recyclable production modes; and actively promote the use of new technologies, new processes, new equipment, and new materials that conserve resources. In the printing industry, CTP technology is itself an environmentally friendly production model compared to the traditional laser image processing technology. In the production of CTP, the use of film and the rinsing process of the film are eliminated, which saves the production of materials and saves water resources, and also greatly reduces the discharge of waste liquid. According to statistics, the effluent produced by CTP plate making is only one-third of that of traditional laser image processing technology. All kinds of processing-free plate technology will minimize the production of prepress plate-making waste liquid, and lead the printing enterprises to gradually enter the era of green environmental protection printing.