PS version of the first line of stereoscopic perspective
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In order to let readers understand the first-line problem of the PS version from the perceptual point of view, we adhere to the practical principle of the first-line attack, and conducted a questionnaire interview with the first-line practitioners in the industry. They are some technicians who are active in the production line and exist in the use of the PS version. The problem is more familiar. At the same time, I also interviewed several experts who have been engaged in printing work for many years, hoping that their experience will bring some inspiration to the readers.
First-line realistic
PS version as a major plate in printing, what issues should be paid attention to during the purchase? What basic performance should the PS version meet?
The purchase of the PS version is a key link, because the quality of the PS version has a fundamental impact on the quality of the plate. Mr. Zhang believes that the PS version should use a branded product with a certain reputation. In the purchase, it is necessary to check whether the PS version of the sand processing is ideal. It should also pay attention to whether the dot reproduction and the printing resistance can meet the requirements. It is generally believed that when purchasing the PS plate, attention should be paid to selecting the PS plate that requires the printing plate, the development performance is good, the cutting size is accurate, the dot reduction is good, the printing durability is high, the ink balance is good during printing, and it is not easy to get dirty.
What problems should the PS version pay attention to during handling, storage and transportation?
Mr. He said that the PS version should not be handled rudely. It should not be stepped on the PS version. The stacking layer should not be too many. It can not be bent. When holding it (especially the single version), both hands should take the two sides of the PS version. Be careful not to bend the plate. Do not let the PS plate collide with the machine or other hard objects to avoid scratching the PS sanding surface.
The printing quality of the PS version has a lot to do with the printing and development operations. What should you pay attention to during the printing and development process?
When printing, you must master the best sensitization time of the PS version, and at the same time fully understand the performance indicators of the PS version. The concentration of the developing solution should be moderate during development, and should not be too thick, resulting in loss of graphics and text; or too light, the development is not transparent, the bottom is black when printing; the development speed should also be moderate.
Why is the PS version of the dot unreal in the process of printing, can not truly reflect the subtle part of the image, the blank part is not clean and so on? How to solve?
There are three reasons for the unrealistic dot: the PS version has no vacuum gas barrier; there is dust, dirt, etc. between the plate and the PS plate; there is a problem with the plate film collage.
The main reason for the loss of the fine part of the image is that the exposure time is too long, and the reason why the blank portion is not clean is mainly caused by insufficient exposure time.
To solve the problem of untrue outlets, Mr. Yang Yong believes that the first thing to do is to check the quality of the film. The dots on the film should have enough blackness. The dots on the film should be transferred to the plate. The covered portion (mesh) transmits light, causing the photosensitive layer of the printing plate to be photosensitive.
What is the cause of the illusion? What is the solution?
Mr. He summarized several main reasons for the fading of the sun after the layout:
1) Poor pumping causes emptiness. The solution is to repair the vacuum pump and related parts of the printing machine to ensure that the vacuum reaches the printing requirements;
2) When the imposition is made, the edges of two adjacent films cannot overlap each other, so as to avoid the squeezing of the layout. The solution is to check whether the film overlaps before drying and whether there is any foreign matter between the film and the PS plate;
3) The film film reverses, or the artificial misspelling causes the layout to become imaginary. The solution is to check whether the film surface of the film is correct before drying, and whether the film film is reversed during the imposition.
Since different PS versions have different development times and conditions, it is best to use the formula provided by the manufacturer. Pay attention to the surface quality when selecting a plate. When developing, you should know the type of developer, how to use it, temperature conditions, and other factors. If the temperature of the printing plate is low in winter, the temperature of the developing solution is likely to drop; if the quality of the printing plate is poor, the printing plate should be replaced, and the developer should not be used for remediation.
In the printing process, the non-image part of the layout is dirty, the graphic part is worn out, and what is the cause of the scratch on the printing plate? How to avoid these problems?
It was learned from the interview that the reason for the partial wear of the PS plate was mainly caused by the following problems: excessive use of the cleaning solution (emulsion), improper printing roller pressure, and partial protrusion of the blanket.
The reason why the non-image part of the layout is dirty is insufficient exposure time, uncoated protective glue, unbalanced ink, ink emulsification, and the like.
The scratches on the plate are caused by the unprotected glue on the plate and the accidental scratching when the plate is taken (upper version). The photosensitive layer cannot be completely removed during development, and the shallower sand and weak hydrophilicity may also cause viscera.
The solution to the plate wear is to re-distribute the dampening solution and check the pH and printing pressure. If it is a roll paper, remove a few layers of paper mixed with sand and clean the film.
What is the cause of the low printing durability during the printing process? How to improve the printing durability of the printing plate?
The PS version of the printing force depends not only on the plate itself, but also on every aspect of the printing and printing process. There are many factors affecting the printing durability of the printing plate, such as shallow sandpaper, thin and uneven oxide layer; running light before exposure, overexposure, overexposure, deterioration of baking glue, excessive baking temperature, and too long baking time Etc., a strong plate cleaning agent or a roller cleaning agent is used in the printing. The printing pressure is too large, the pressure of the printing plate and the blanket is not uniform, and the plate is tight and uneven by the plate, and the rubber roller and the blanket are aged. The liquid concentration is too large, corroding the printing plate; the printing paper is rough, the powder is dropped, the hair is lost; the ink layer is too thick, and the ink particles are coarse.
The first-line technicians interviewed stressed that in order to improve the printing durability of the printing plate, it is necessary to master the correct exposure time, development method and operating procedure in order to achieve the best use of the plate. For example, developing under standard conditions; formulating an appropriate developer, paying attention to development time; not using inappropriate drugs; reducing the number of wiping; using a mild cleaning agent; adjusting the printing pressure.
At the beginning of printing, the printing plate is not good, how to deal with it? What should I do when the photosensitive layer peels off or detaches?
The main reason for the poor printing of the printing plate at the beginning of printing is that the specified protective glue is not used, the protective glue is too thick, and the rubber is unevenly distributed; the printing plate runs out, the lipophilicity of the graphic part is lowered; the protective rubber is too thick, too much, etc. Caused. The poor ink in the middle of printing is mainly caused by the excessive composition of the glue in the fountain solution.
The PS plate is peeled off and peeled off mainly due to problems such as plate protection and poor storage. If it is caused by the adhesion of chemicals (strong acid, strong alkali, etc.), it should be adjusted. If it is a plate problem, it should be with the manufacturer. Exchange.
How to strengthen developer management?
Mr. He believes that the preparation of the developer must be reasonable first, and too thick or too thin will have a great impact on the development effect. In the storage of the developer, attention should be paid to the influence of light, temperature and humidity on the developer. For example, in winter, if a heating device such as gas is used, the concentration of carbon dioxide in the room will increase, causing the developer to age, so it should be used as much as possible. Carbon dioxide heating equipment.
1) Purchasing
PS version of the purchase, recognize the price trap is a wise move, other brands of PS version quality The grades are similar, the difference between the plate itself and the photographic performance is not big, but the quality stability is slightly different. In general, although the requirements for the plate are not very high, the choice of plate should not be considered as the lower the price, the better. For companies with special requirements for speed, such as newspaper printing companies, one problem to note is that many PS manufacturers are not improving the raw material technology in terms of improvement in speed, but by increasing the amount of sensitizer. The purpose of the degree, so that although the speed of light has gone up, but the printing resistance is low, and the alkali resistance is also reduced.
2) custody
The most important problem in the PS version of the storage is to avoid light, but also pay attention to moisture and alkali. In general, the PS version is well preserved, the shelf life can be 2 to 3 years, and the printing durability will not change much with time. The industry has reached a consensus plate life of 1 year, the root cause is that many domestic manufacturers are not standardized on the management of plates, and the PS version is affected by the environment. In order to avoid disputes, PS manufacturers generally have 1 The year is the retention period, and this period is actually quite reasonable.
3) Light source
The choice of light source in the printing plate is a noteworthy problem. The iodine gallium lamp is a light source suitable for printing. It has high luminous efficiency and can be used continuously. The spectrum wavelength of its emission is in the range of 350-450 nm, at 417 nm. It is the highest peak and is effective for most plates. This kind of light source emits strong ultraviolet rays. When used, it uses a opaque material such as artificial leather to make a protective cover or a protective curtain to prevent direct ultraviolet rays from damaging the operator's eyes.
4) Printing resistance
There are many factors affecting the printing durability, including the quality of the plate itself, paper, ink, printing pressure, etc., more important is the PS plate manufacturing technology. From the current point of view, the fundamental reason for the poor printing resistance of the domestic PS version is that the removal of electrolytic fog and oxidized fog is not very thorough, and the PS plate photosensitive adhesive is also a relatively large factor; in addition, the adjustment of the machine pressure It is also very important that experience has shown that with different pressures, the printing durability of the plates is significantly different. In addition, the acidity and alkalinity of paper and ink also affect the printing durability of the printing plate.
5) Ink performance
The experimental data shows that the change of the sensitizer content in the photographic adhesive has a great influence on the ink performance, which indicates that the ink repellency has a great relationship with the photographic adhesive. If the resin content is too large or the resin quality is poor, the ink performance will also be affected. However, the amount of sensitizer is not much better, and the high speed of the sensitizer decreases. Therefore, how to realize the rationalization and scientificization of the ratio of resin to photographic adhesive is very important.
6) The outlet is not true
The two teachers analyzed that in addition to the external factors, the outlets are not real, but also involves a problem of the surface of the rough surface. This is very important to eliminate the false points. If the periphery is very solid, residual air in the middle will cause the light to refract. Newton's ring causes damage and loss of small mesh points, which leads to untrue dots. The main method to solve this problem at present is to solve by vacuuming twice or adding a matte gas guiding layer on the PS plate. There are also many methods for forming the matte gas guiding layer. Generally, a small transparent particle is sprayed on the surface of the PS plate. These small particles are insoluble in water but soluble in an alkaline liquid, and have no effect on development. The purpose of adding the air-conducting layer is mainly to solve the Newton's ring problem, not only the speed is fast, but the effect is also very good.
7) Dirty on the layout
The dirty surface of the plate mainly occurs during the exposure and development process, that is, the photosensitive adhesive is not completely removed. In addition, the photosensitive adhesive itself can also cause the surface of the printing plate to be dirty. For example, the problem of returning to the blue, the trace insoluble matter in the photosensitive adhesive is deposited on the plate surface to cause blue back. In severe cases, it will cause visceral. The version is generally caused by the performance of the PS version, but uneven or excessive machine pressure will result in the loss of the version.
At present, relevant domestic standards have been introduced. Experts suggest that each factory should formulate corresponding enterprise standards for the plate making process according to its own situation, take the road of standardization, ensure the quality of the PS version, and enhance the comprehensive competitiveness of the enterprise.
The PS version of the first-line problem is actually a lot. We just discussed the problems of some aspects of the PS version. I believe that the discussion on the first-line issue of the PS version will continue to deepen with the development of the PS version of the industry. In the fierce market competition, The resolution of these problems will provide a more valuable reference for the development of the media industry.