The primary difference between plate types is the sensitivity of the plate. The sensitivity of various plates in the CTP version is roughly as follows: a conventional printing plate of 2000 mJ/cm2, a thermal printing plate of 150 mJ/cm2, a polymer printing plate of 0.04 mJ/cm2, and a silver salt printing plate of 0.03 mJ/cm2. This difference in sensitivity is not only for exposure, but also for all production processes. The demand for sensitizing emulsions and coated aluminum sheets is very meticulous. Fuji Xingguang needs to be strictly controlled and insists on small mistakes.
A printing plate skill director told about the production of traditional and digital plates. He said: The pioneers of CTP skills put the film in the printing frame, then copied it on the plate and exposed it with a few kilowatts of UV light for a few minutes. Print, then develop, rinse, and apply glue. For this reason, in a few decades, with a wide processing tolerance, the printing plate can achieve a stable printing effect with a little or worse printing frame.
The traditional printing plate raw materials are firstly the high-priced aluminum coils, as long as several aluminum plants supply quality control, such as Bridgnorth, Novelis or Alcan. The traditional printing plates are produced on huge production equipment. After the aluminum coils are replaced, the successive aluminum strips are divided into 10 processing processes.
In the first step, the aluminum coil is supplied to the equipment by two unwinders like a rotary paper roll.
The second step is e-commerce, pre-purification, and the removal of the natural oxide layer on the aluminum surface.
In the third step, the electrolytic roughening causes the printing plate to generate sand.
In the fourth step, the resulting film is removed by post-corrosion.
The fifth step is metal packaging, anodizing, and the roughened aluminum oxide layer having a thickness of 0.5 to 3.0 μm is mechanically and chemically hardened.
In the sixth step, the plate is sealed to allow the plate to coat the photosensitive layer very well and adhere to moisture.
In the seventh step, the photosensitive liquid packaging container is coated and boring.
In the eighth step, a matt layer is applied and boring, thereby forming a fine air passage, which improves the degree of vacuum during printing.
In the ninth step, the laser beam is used to probe the surface mount of the printing plate, and some of the reflections that are not required are recorded as the defects of the printing plate, and the symbols are marked on the plate, and will be in the cutting process. It is eliminated.
In the tenth step, in the winder in the storage tower, the coated aluminum strip is rolled into a roll printing factory, and the aluminum strip may be supplied to the cutting device. The aluminum strip is cut into a plate size on the cutter and pierced into the barrier paper for packing. Each package must be printed with the date of manufacture and the date of warranty.
The CTP version of the production process is monitored by a process control system that monitors the measurements of all stations. The cost of this plate production line is in the range of hundreds of euros.
The price of polymer plates, digital silver salt plates and photopolymer plates is about double that of traditional printing plates. If you use the high cost of printing plates and entering the market to explain this kind of landscape packaging logistics, customers can accept of. Because the process from the imposition of the art to the digital version has been completed with CTP, the production process is greatly simplified. The beginning of the thermal skills presented in 1997 was used on the CTP. In 2000, Agfa launched a violet laser plate that can be processed under yellow safe light. Since the adoption of photopolymer plates, it has become an attractive choice.
Thermal plates, the cost of this plate has many factors. The mechanical transfer of the digital plate from the beginning of the plate to the exposure machine, and then from the exposure machine to the development and post-processing system UV printing, the request for the plate is higher, as long as the use of advanced aluminum is satisfactory. In addition, it has a higher request for the intermediate barrier paper because it is necessary to actively remove the barrier paper on the exposure machine. For example, with regard to the newly launched: Energy series printing plate, it is necessary for the raw aluminum for the Energy Marathon printing plate to be roughened in the course of special work. For the sake of progress: the chemical resistance of the Energy Elite plate, the plate needs to be coated twice with Lekai, which means that the customer needs to take the additional investment of the second coating unit.
Because sensitivity is necessary to adhere to small tolerances during plate coating, boring, and preheating, it is necessary for the entire surface of the plate to obtain the same exact temperature so that the sensitivity does not change during printing. Traditional plates only need to be exposed in the printing frame, while digital thermal plates need to be checked on all models of Agfa.
If the traditional printing plate is planned in batch production in the production line and can be packaged and supplied immediately at the terminal, then the positive thermal version of the positive printing plate needs to be matured, and the sensitivity of the printing plate to the final state is stopped under the control condition. This process needs to be monitored by quality inspection. A thermal plate requires a very good package to avoid getting wet. The CTP version then sends the plates to a central warehouse in Europe, where thermal plates are stored in air-conditioned rooms. The process of transport to the printer and the inventory at the printer are also typeset under control conditions in order to maintain the temperature stability of the plate. Because of the summer heat (no problem with traditional plates), the CTP version will have uncontrollable pre-exposure. All of these nominal costs add up to the fact that thermal plates are more expensive than traditional plates.