Analysis of common problems in the use of CTP plates
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CTP technology has successfully entered the field of vision of the printing industry, and its development and application have brought about timeliness and technical double optimization in the actual printing production process. In this process, the performance and stability of CTP plates can not be ignored, domestic plate suppliers basically have more mature plate production technology. Based on the experience of using CTP plates, the author analyzes the problems of the plates during use, mainly from the surface problems of the plates, the problems caused during the development of the plates, and the problems arising during the printing process. Analysis.
First, the use advantages of CTP technology
1. Timeliness
Due to the characteristics of the CTP technology itself, the steps of the film are saved, which greatly saves the production cycle. The feedback speed of the CTP process is fast. If the traditional film products are printed on the printing machine and found to have some problems, it is impossible to re-edit the plate in a short time, and finally the production delay and other consequences. After the publication of CTP, the revision can be modified in a short time, and the progress of production is not affected. The specific use can be seen in the figure below, the specific process of CTF process and CTP process is given.
2. Technical
Compared with ordinary PS plates, the printing capacity of CTP plates can reach more than 200,000 sheets, which means that for the operation of a large number of printed sheets, the use of CTP plates can save a lot of cost to a certain extent. In addition, CTP technology is more conducive to the restoration of files, the level of the outlets is more clear, the performance is more accurate, and the possibility of doing a good FM network is provided. The controllability of the CTP process is very high. The measurement and monitoring of the plates are carried out by the corresponding instruments, and the data is strong, so that the entire printing color management can be completely realized, and each step can be sputtered with corresponding data, which is more convincing. scientific.
The strong advantages of CTP technology make it widely used in printing enterprises. The following gives an analysis and corresponding solutions to some problems encountered in the use of CTP plates.
Second, the surface problem of CTP plate
1. Apparent problems before making plates
Generally, CTP plates are divided into inner and outer packagings. The outside is a corrugated carton with a packing tape. The inner packaging is a moisture-proof black wrapping paper. The plate is generally separated by a sheet of paper. The main problems that occurred before we made plates were white spots, dirty spots, bubbles, scratches, and horseshoe prints.
① For "white spots", the causes and solutions.
During the production process, when the photosensitive adhesive is applied, it is a coating problem and can be solved by an improved coating process.
During the transportation process, the friction between the backing paper and the layout can improve the logistics and the lining paper, and the liner paper without paper powder is used.
During the storage process, if the temperature of the warehouse is too high or the humidity is too high, the storage conditions can be improved.
② For "dirty spots", the causes and solutions.
During the production process, the coating problem or the dirty spots on the rubber roller can improve the coating and inspection of the production line to eliminate the dirty spots.
③ For "bubbles", the causes and solutions.
During the production process, when the photosensitive adhesive is applied, it is a coating problem and can be solved by an improved coating process.
④ For "scratch, horseshoe print", the reasons and solutions.
During transportation, it should be handled gently when handling, to avoid external impact on the layout, preferably with pallet transport.
2. Apparent problems after plate making
The CTP plate material passes through the plate making equipment, and the developing device can be printed on the printing machine. Look at the layout to see if there are fingerprints, scratches, streaks, dirty spots, white spots and so on.
① For "fingerprints", the causes and solutions.
During the production process of the plate, the drying temperature is not high enough, the plate is too tender or the finger is dirty, and the sweat is stuck on the plate. In this case, the glove should be worn when the plate is taken, or Take the paper with the liner.
② For "scratch", the cause and solution.
The conveying device of the plate making machine is caused by the developing machine, and the conveying device of the plate making machine can be inspected and cleaned to check whether the driving of each roller and brush in the developing machine is normal and defective.
③ For "streaks", the causes and solutions.
Generally, it is caused by abnormal development, and the concentration, temperature, running speed, and pressure of each roller and brush in the developing machine are checked and adjusted.
④ For "dirty spots", the causes and solutions.
During the production process, there is no sealing treatment or insoluble impurities in the photosensitive adhesive. The production process should be improved and the quality inspection should be checked.
When developing, the developing solution is not effective enough, the water pressure of the washing process is not enough, or the pressure of the rubber roller or the brush is insufficient. The concentration of the developer should be adjusted, or the temperature should be increased, the speed of the plate should be reduced, the water pressure should be increased, and the appropriate rubber roller and brush pressure should be adjusted.
The exposure of the plate-making equipment is insufficient or the focus is not accurate enough. The focus value of the device can be adjusted, the exposure is increased, and the rotation speed is reduced.
⑤ For "white point (off-line)", the cause and solution.
The development is unstable, the parameters of the developer can be adjusted, and the pressure of the brush and the rubber roller can be adjusted to solve.
The liner paper is damp and frosted. It is recommended to replace the liner to prevent the liner from getting wet.
Third, CTP plate material development problem
After the plate-forming development, the CTP plate will have the following common problems, including the scanning line, the blue part of the blank, the unevenness of the flat net, and the fact that the solid part is not.
1 For the "scan line", the cause and solution.
Plate-making equipment problems, equipment static electricity, laser head problems, resulting in the generation of scan lines, please board machine engineers to debug equipment.
During the plate making process, the focus is not accurate, or the exposure is not good, it will also cause the scan line, and the device can be re-adjusted.
During development, insufficient development can be solved by adjusting the development parameters.
2 For the "blank part blue", the cause and solution.
During the plate making process, the exposure is insufficient, the exposure test is repeated, and the exposure value is increased.
During development, insufficient development can enhance development, adjust development parameters, and check if flushing water enters the developing tank.
During the sizing process, whether the protective adhesive is contaminated or expired, replace the protective adhesive suitable for the sheet.
3 For the "flat network uneven", the reasons and solutions.
During the plate making process, the plate making parameters are inaccurate, the plate surface of the plate making machine is not flat or dirty, the vacuum of the plate making machine is not good, and the plate material is not adsorbed tightly, which can be solved by adjusting the plate making machine.
During the development process, the development is uneven, the circulation system of the developing device, the transmission system are checked, and the development parameters are adjusted.
Plate problems, uneven coating, uneven plate base, and improved production process.
4 For the "real part of the real part", the reasons and solutions.
Excessive development, the loss of the solid part after development should not exceed 10%, adjust the development parameters.
Fourth, the problems in the CTP printing process and other
The most concentrated problems in the printing process of CTP plates are mainly dirty, no ink, and missing plates.
1 For the "dirty", "local version", "full version of the version", the reasons and solutions.
During the plate making process, the exposure is insufficient, the exposure test is repeated, and the exposure value is increased.
During development, insufficient development can enhance development, adjust development parameters, and check if flushing water enters the developing tank.
The ink is emulsified seriously, and the relevant parameters of the ink path and water path are adjusted.
The water is too small, or the water bucket fluid can not be well adsorbed on the hydrophilic layer of the plate, increase the amount of water, and adjust the ratio of the water bucket.
The protective adhesive is too thin or uncoated, coated with protective glue to protect the plate.
For the reason of the plate material, the current and voltage are not normal during the aluminum plate-based oxidation and electrolysis process, and the production process is improved.
2 For "no ink", the reasons and solutions.
The reason for the plate is to improve the production process.
The reason for pre-press production is that the protective glue is too thick, the protective glue does not match the plate, and the development is excessive. Pay attention to the pre-press operation.
For printing reasons, the water hopper does not match the plate, or the ink, the stencil and the plate do not match. The dampening solution, ink and cleaning solution should be selected to match the plate.
to sum up
Today, with the popularization of CTP technology, strengthening the training of relevant technical personnel, correctly and timely handling various problems in the use process, can fully reflect its value, and hope that the above analysis can play a certain role.