Ctp is a long-term choice
The choice of plate has a direct impact on any ctp process. Therefore, when choosing a thermal, violet or visible light plate, you should choose carefully.
It is surprising that the user rarely mentions the plate and its development process when selecting a computer-to-plate system. According to Gary Wall, general manager of IGP, a supplier of ctp printing equipment, "This is a problem we have to consider. People usually only consider whether the appearance of the tool is good or not, and ignore the technology itself."
In the past, there were always many obvious differences between different Ctp plates and their development processes. With the continuous advancement of plate-making machine technology, this situation has been alleviated accordingly, and the common features on the plates are increasing.
In fact, every company that has a ctp system (whether it's a thermal or visible light plate) claims that the quality of the overprint has improved greatly since the use of cleaner plates. In addition, since the plate making process does not use film, the bottleneck problem of slow plate making speed is solved, the production efficiency is greatly improved, and the waste is greatly reduced.
So far, the main differences between the various ctp systems still revolve around the type of plate used and its development process. It is true that all metal plates, whether thermal or visible, use the same aluminum plate as the substrate, but the granulation and anodizing methods used by various manufacturers for aluminum surfaces are not the same.
However, the main difference between the various plates is the type of laser energy, heat source or source used to activate the reaction when exposing the thin emulsion coating on the aluminum plate. Since the laser can only emit energy at a fixed wavelength, it is necessary to adjust the characteristics of the emulsion layer of the imaging plate to match the wavelength of the specific energy emitted by the laser. Therefore, each laser type requires a specific plate coating material formulation to ensure that the plate reaches the reaction peak in the corresponding wavelength region of the laser.
Ablative layer
For so-called "visible light" printing plates, the coating is made of a photopolymer or silver salt material and is photosensitive; while the thermal plate coating consists of a temperature sensitive photopolymer or ablative layer. Each has its own advantages and disadvantages in terms of image quality, exposure speed, printing and development processes.
First consider the quality of the image. The thermal version is primarily sensitive to infrared lasers of 800-850 nm. The dual nature of the coating means that images can only be recorded if the energy amplitude and phase changes meet certain requirements. That is to say, the plate area that does not reach the target temperature does not react and is not exposed. Therefore, it is possible to produce clean, sharp-edged dots that can be used to make fine screen lines. In addition, the plates can be baked for long-run printing or in the production of UV inks.
However, the heat-sensitive coating requires more energy to react than a silver salt or a slightly less sensitive photopolymer material.
The thermal version is similar in sensitivity to traditional plates and can be imaged with relatively low energy lasers. In general, they can achieve higher dot resolution, while photopolymer emulsions require more than 100 times more laser energy.
Printing resistance when printing on the machine
However, according to Fujifilm, the company's recently launched violet laser polymer plate can achieve similar quality to the thermal plate during the copying process. The printing plate can be printed from 200,000 after printing on the plate. Printing increased to 1 million impressions. This has caught people's attention.
On the other hand, the plate requires a 30mW laser, and unlike the thermal version, all visible plates need to be handled in a safety light environment (because they are sensitive to sunlight), and the violet laser plate can be bright yellow. Handle under the lamp. All visible light plates may also cause underexposure or exposure transitions due to differences in energy intensity and exposure time. Too large or too small a concentration of a chemical, and a too long or too short development time can cause problems.
In fact, the development process of the thermal plate is the simplest. It tends to use less chemicals and greatly reduces waste. This is very important because the cost of chemicals can increase the cost of plates by 10% or more.
The following are related to maintenance and maintenance issues. For example, according to Kodak Polychrome Graphics, a medium-sized company with two or four presses spends an average of six labor hours per week to clean the developing machine that processes visible light plates.
Since KPG does not produce this type of printing plate, they have a say in this regard. Of course, visible light printing is also making progress. For example, the new Fujifilm Brillia LP-N3 printing plate not only has a new sensitive layer, but also adopts a new development technology. This technology is said to reduce the use of chemicals by the printing house, prolong the life of the developer, and also reduce the developer residue (the treatment of this residue becomes a major problem in the development of photopolymer plates).
Additional process
On the other hand, thermal plates require some additional processing, such as pre-heating the plates to achieve exposure sensitivity, pre-cleaning before development, and back-blanking to enhance image areas for chemicals. Corrosive, improve the printing durability. These operations not only take up space, but also consume energy and increase operating costs.
However, these aspects have also been improved, especially in terms of the robustness of the printing plate, without the baking plate, the printing durability of the printing plate is continuously improved.
For example, Fujifilm's Brillia LH-PIE positive version is used in medium-volume operations, neither pre-heating nor back-blanking. The plate has a very good resistance to corrosion and can be used with uv ink without baking. Moreover, such plates can be processed using standard plate developing equipment.
In fact, the compatibility of the development process is very interesting because each plate requires a different chemical, even if the same type of plate requires a separate developing device.
In other words, it is not possible to process different types of printing plates using the same developing device, and in some cases, it is not feasible to use the same developing device to process the same type of printing plates from different manufacturers.
This type of problem occurs more in the visible light plate than in the thermal plate. For example, IGP's ThermaLine processor can handle a variety of thermal plates on the market, including special sizes.
Perhaps the most important point in the ctp development phase is how to combine thermal and conventional media development processes. Paul Burton, general manager of Replica in Redhill, puts this in mind. The company recently purchased a Screen 8000II platesetter for developing the Electrora Excel plates produced by KPG.
He said: "In fact, we can simultaneously develop ctp and traditional plates on the existing developing machine, which saves unnecessary costs, and it takes extra space to place another developing machine."
In considering environmental factors, no technology is perfect, and each has half of its advantages and disadvantages. Just like the silver salt plate, a silver recycling device will be installed.
Possibility of recycling
Agfa has long discovered that one of the main reasons why the printing of the newspapers in the Nordic countries has switched to the use of silver salt is that they want to work towards the “zero development waste into the ditch”. That is, they want the plate to be recyclable and point to a key green rule – making products from recyclable materials.
We have to wait and see if this idea will become a trend in other market sectors or other countries, with laws and regulations on recycling, recycling and disposal requirements. Interestingly, Mr. Wall of IGP said, “As of September 2001, our thermal-type printers have been selling very well, but since then, the sales of visible-printing printers have also higher."
But he attributed this reduction to Heidelberg's entry into the visible light printing market. It may also be due to the plate-making machine of visible light plates, especially the latest purple laser version of the platesetter, which is more suitable for small-scale enterprises that have just started to install ctp systems.
In general, the number of visible and thermal plate systems installed in Europe has been on a par with each other, but whether the actual plate consumption is the same is controversial, especially when considering that most newspaper printing companies use visible light. When printing plates, the data is harder to count. Most companies in the UK use visible light-sensitive photopolymer plates.
This development should have caused the price of these plates to fall, but it is hard to say how the progress is, because so far, the plates are mainly sold as part of the ctp system, and the price of the hardware often depends on the size of the plates in the contract and length.
Potential impact
Another factor that has a potential impact on plate prices is manufacturing and processing costs. Although the price of silver salt emulsions is more or less expensive than photopolymers, the overall cost of raw materials remains relatively average. As Fujifilm claims, their photopolymer-based Brillia series ctp plates are developed in the same way as traditional plates.
Mr. Steve Doyle, Head of Application Technology at KPG, said, “The application of thermal layers is the same as for traditional plate layers, which gives manufacturers like us the flexibility to supply.”
But he added, “Ctp needs a higher standard. So far we have been producing a thermal version for seven years. We have a lot of experience and technology to introduce many simple steps to ensure a consistently high quality and minimum. waste."
Strategic Decision
Mr. Steve Doyle believes: “Improving ergonomics can ensure price declines. We have made strategic decisions and plan to produce thermal versions in Europe, the US and Japan to ensure suppliers are closer to customers. The real impact of product processing on prices is Less than the impact of print volume, competitiveness and market pressure."
This will give us the ultimate choice for the future potential of different technologies. Advocates of thermal technology point out that their technology is the only technology that may offer development-free operation.
It is important to consider that a chemical developer is a very expensive device that requires maintenance and waste disposal. This is a very important factor.
This flush-free printing plate is now available, and the main supplier is Presstek. There are now a range of thermal plates that are completely free of development and suitable for a variety of jobs.
By that time, we might already have a similar plate-making machine that can image traditional plates. The traditional plates are much cheaper than the ctp plates. Who knows the future?
If you plan to switch to ctp technology, keep in mind that not everyone knows the technology very well. The best advice at the moment is to look at the existing materials and equipment and calculate all the costs that the owner needs, based on the plate. And processing costs to calculate the difference between the platesetter, because this is the most important factor in the long run.