Home-made liquid formulations positive PS version has been widely used in China's printing industry. The various quality problems reflected in actual production directly affect the quality of printed matter, production costs, and the economic benefits of the company. The quality problems of the positive PS version can be divided into two major categories: the quality of the PS version and the quality of the PS version. Based on many years of experience, the author tried to systematically summarize the problems from the quality problem to the cause, from prevention to elimination.
One, the quality problem of positive figure PS version body
Since China's PS version experiment was successfully developed and put into production in 1973, the domestic PS edition manufacturing industry has developed rapidly. At present, there are more than 30 manufacturers of PS plates in the country, and they have their own "Pattern-type PS plate industry standards." In general, any manufacturer who can register for the external PS version will have its own quality inspection standards. However, due to the differences in the standardization of technologies, equipment, and manufacturers, the quality of the PS version varies from place to place, from factory to factory, and from time to time. Some quality is still unstable. For the PS version of the quality of the problem, the use of manufacturers often pay attention to not enough, and often even mistaken for their own use of the problem.
1. PS version background color is not good. After the exposure, the contrast of the color is too small, which causes the multiple printing plates to be trapped in the line and is inconvenient to observe when developing.
2. The development time is not well understood. The development is stronger and the small outlets are damaged. If the development is weak, the development will be incomplete and the printing will be dirty. This phenomenon shows that the development tolerance of the PS version body is too small. A good PS version has a larger development latitude, and a little more development time can also maintain the integrity of small dots. A shorter time can also keep the printing plate from being dirty, develop a little stronger, and develop a little weaker to develop completely. Poor-quality PS plates require more stringent development conditions and require special attention.
3. After development, there is a "blue bottom" that causes the printing to be dirty. Even if the concentration of the developer is increased, the enhancement of the development is not effective, and even the graphic and text are destroyed, and the "blue base" has not disappeared. This is mainly due to the fact that the color material in the emulsion is deposited deep in the sand. Overexposure can generally be used for remediation.
4 is not easy to ink, PS version of the machine is not easy to ink on the printing or not at all, because there are many reasons, involving the quality of PS version of the body there are two: First, the PS version has been more than a year of preservation period Or improper preservation, such as the preservation of the ambient temperature is too high (more than 30 °C), relative humidity greatly exceed 65%, too strong light; the other is the photosensitive adhesive viscosity is too low, photosensitive coating is too thin.
5. Partial "flower version", paste version. The thickness and flatness of domestic PS plates have a certain gap compared with the international level. The thickness is inconsistent, the over-standard and flatness are not uniform, and the quality of the PS plate is fundamentally affected, causing local rapid wear and tear. , and then fell version and dirty.
6. Broken version. Discontinuation of the printing process is often due to the fact that the lead plate base is manufactured by the cold rolling process, and the tensile strength is improved, but the fatigue strength is low, brittle, and it is easy to cut off the plate. If the printing pressure is too high and the machine speed is fast, it will be more likely to break the plate.
7. Partially dropped. After the roughening of the electrolysis, the gray quality of the printing plate base is not completely removed, and the partial photosensitive layer is not strongly adsorbed. Printing hundreds or thousands of sheets may partially print out.
8. Locally out of print. Before the application of the photosensitive liquid, the layout was not cleaned, leaving traces of acid flow when hanging, resulting in partial plate-off.
9. PS plate surface roughness is not good, coarse sand, too thin. Abrasives are too thick, water capacity is insufficient, easy to dirty; fine sand eyes, the photosensitive film in the microporous is not easy to clean, the base is easy to pollution, easy to stain on printing.
10. PS version of ink affinity, poor alkali resistance. Sensitizer deteriorated due to failure.
11. Improper proportion ratio of photosensitizer, such as film-forming agent content is too low, sensitivity declines, and resistance to printing force is low. If the content of the photosensitive resin is too low, the wear resistance and alkali resistance of the photosensitive layer will be reduced, and such a PS plate has low resistance to printing.
12. The photosensitive film is too thin, and the alkaline developing solution easily damages the oxide film during development. When printing on the machine, the printing plate and the blank space are dirty.
PS version body quality problems, in general, the use of manufacturers can not be solved, all they can do is to timely feedback to the manufacturer, prompting the PS version of the quality of the fundamental solution. If the problem cannot be solved, the PS version of other brands and models will have to be re-used. Do not mistake the quality of the PS version for use.
Second, PS version printing quality problems
Shaiban is a "bridge" process in platemaking and printing. Its status is very important. Although the PS plate is easier to handle and the quality is better than that of the flat plate, it often causes troubles in the manufacture of the PS plate. The use of PS version is not satisfactory.
1. The image is imaginary and dirty. 1 The tape is too close to the image on the tape, the image pad is imaginary, and there is dirty printing on the tape; when the imposition is made, the bases overlap, the image pad is imaginary, and sometimes there are dirty marks. Solution: Try to keep the proper distance when the tape or imposition sheet is overlapped. Adhesive smears can be removed with a dirt remover or removed with a diffuse film double exposure method. 2During printing, there are dust, sand, and other dirt on the PS plate, causing the image to be dirty on the pad. Therefore, you must carefully check the layout before the printing, remove all the dust, do a good job of indoor health, the best is to print in a dust-free environment. 3 When printing, the glass is not clean. There are glue points to dirty the image pad. According to the operating process requirements, the glass must be wiped clean before printing, otherwise it is not allowed to print. 4 Shaiban vacuum pump performance is poor, lack of vacuum, the contact between the plate and the film is not true, causing sun drying. The treatment method is to overhaul the vacuum pump, and the vacuum degree must be more than 0.08 MPa. 5 The air chamber of the printing machine has a poor airtightness and leaks, making it inspiratory. Printing plates are often sunburned due to aging of the gums and should be replaced or glued. 6 The bottom of the printing plate is uneven and the suction is not uniform. The contact between the partial film and the PS plate is not real. There are three ways to solve this problem: First, check if the bottom of the printing plate is uneven and flatten it when uneven. Second, select the porous wool pad to promote the contact between the PS plate and the film. Third, use the second suction method, that is, the first time. Suction stops releasing part of the gas, and then inhales again, which promotes close and even contact between the PS plate and the film. 7 film image density is not enough, when the print version is light through, the image is exposed, causing the image to send out of ink. In principle, printing cannot be done when the image density is less than the standard, and it must be re-plated. Sometimes you can try to pull the light far away, so you can reduce or avoid sun drying to a certain extent.
2. The blank part of the plate is dirty. 1 underexposure, resulting in incomplete decomposition of the sensitizer, the development is not completely removed, causing the blank part of the dirty. If the printing plate is not printed on the machine, it can be rescued by the second development method, but this phenomenon is only applicable to underexposure situations, and severe cases cannot be saved. Determining the proper exposure time is the key to determining the quality of the printing plate. With a continuous ash grading test, the 0.45 densitizing without ink absorption will effectively solve the problem of underprinting caused by printing plates. 2 Insufficient development, non-photosensitive film removal is not clean, resulting in dirty plates. The reasons are: insufficient developer concentration; insufficient development time; low developer temperature; ideal development temperature is 22±2°C; The 3PS version of the photosensitive layer is unevenly coated, the thickness is not uniform, and the degree of decomposition of the photosensitive resin during the printing is different, resulting in dingy. If the photosensitive adhesive coated with a centrifugal baking plate machine is often radiated, and the four-sided rubber is easy to be dirty, it can be rescued by local exposure or partial development. 4 Incorrect lifting of the ink on the dirt, the ink can be washed off with turpentine, and the ink is refreshed again. 5 Wipe protection glue is improper, there is a leak in the place, resulting in dirty. 6 In addition to dirty methods cause blank parts dirty. The reason is that: in addition to the amount of dirty agent; repair time is not sufficient; in addition to the dirty agent on the printing plate is not timely rinse and wipe. 7 layout was blue and green. This version can be used in addition to dirty agent to identify, can be removed in addition to dirty agent, it shows underdeveloped or underexposure; if you can not get rid of, then the PS version is not completely sealed, belonging to the quality of the PS version of the body, and The print version is irrelevant and cannot be salvaged. Contact with the manufacturer to resolve it. 8 The plate is light blue after development. This is due to the fact that the plate has been stored for a long time or the temperature at the time of applying the photo resist is too high, which causes oxidation of the aluminum oxide on the surface of the aluminum plate and the photosensitive layer. It is insoluble in the developer and does not cause dinging under normal conditions. It only appears dirty when using dirt remover. This is because the dirt remover dissolves in a bluish color, accumulates in a more color-preserving circle, and becomes dirty after drying. The solution is: wipe the lysate with a damp cloth immediately after it is dirty, and it will not be dirty.
3. Printing plates do not absorb ink. 1 overexposure: the original density is too low, when the print version of light transmission; exposure time is too long; PS version is not properly preserved, light leakage, storage period is too long, deterioration, bad ink absorption. 2 excessive development; developer too concentrated, too strong alkaline; too long development time; developer temperature is too high. According to the different characteristics of different manufacturers of different brands of PS version of the sensitizer, the use of appropriate formulations, matching ratio of the developer, with the test strip detection and control, is an effective way to steadily control the development of quality. 3 The protective glue becomes acid and deteriorates, which often occurs during the high-temperature rainy season. Dirty and dirty, rubber road, causing no ink.
4. The picture is too light. 1 Excessive exposure should reduce exposure time. 2 excessive development, should reduce the development time. 3Insufficient density of the original plate, transmission of light when printing, so that the network damage is reduced. 4 The printer is under-pressurized or has few gaskets. Adjust the pressure or gasket properly. The 5PS version is too coarse and its mesh is damaged and becomes lighter.
5. The graphic is too deep. The reason why the graphic is too deep is often the opposite of the reason that the pattern is too shallow, and the solution is the opposite. 1 underexposure, should increase the exposure time. 2 underdeveloped, should enhance the development time. 3 The original non-graphic part has a high degree of fog, and the transparency is not good, and the exposure time can be appropriately increased. 4 The pressure of the printing press is large or the thickness of the liner is thick. The pressure or the liner should be properly reduced. 5 ink is too thin, too soft. Processing method: Update the ink.
One, the quality problem of positive figure PS version body
Since China's PS version experiment was successfully developed and put into production in 1973, the domestic PS edition manufacturing industry has developed rapidly. At present, there are more than 30 manufacturers of PS plates in the country, and they have their own "Pattern-type PS plate industry standards." In general, any manufacturer who can register for the external PS version will have its own quality inspection standards. However, due to the differences in the standardization of technologies, equipment, and manufacturers, the quality of the PS version varies from place to place, from factory to factory, and from time to time. Some quality is still unstable. For the PS version of the quality of the problem, the use of manufacturers often pay attention to not enough, and often even mistaken for their own use of the problem.
1. PS version background color is not good. After the exposure, the contrast of the color is too small, which causes the multiple printing plates to be trapped in the line and is inconvenient to observe when developing.
2. The development time is not well understood. The development is stronger and the small outlets are damaged. If the development is weak, the development will be incomplete and the printing will be dirty. This phenomenon shows that the development tolerance of the PS version body is too small. A good PS version has a larger development latitude, and a little more development time can also maintain the integrity of small dots. A shorter time can also keep the printing plate from being dirty, develop a little stronger, and develop a little weaker to develop completely. Poor-quality PS plates require more stringent development conditions and require special attention.
3. After development, there is a "blue bottom" that causes the printing to be dirty. Even if the concentration of the developer is increased, the enhancement of the development is not effective, and even the graphic and text are destroyed, and the "blue base" has not disappeared. This is mainly due to the fact that the color material in the emulsion is deposited deep in the sand. Overexposure can generally be used for remediation.
4 is not easy to ink, PS version of the machine is not easy to ink on the printing or not at all, because there are many reasons, involving the quality of PS version of the body there are two: First, the PS version has been more than a year of preservation period Or improper preservation, such as the preservation of the ambient temperature is too high (more than 30 °C), relative humidity greatly exceed 65%, too strong light; the other is the photosensitive adhesive viscosity is too low, photosensitive coating is too thin.
5. Partial "flower version", paste version. The thickness and flatness of domestic PS plates have a certain gap compared with the international level. The thickness is inconsistent, the over-standard and flatness are not uniform, and the quality of the PS plate is fundamentally affected, causing local rapid wear and tear. , and then fell version and dirty.
6. Broken version. Discontinuation of the printing process is often due to the fact that the lead plate base is manufactured by the cold rolling process, and the tensile strength is improved, but the fatigue strength is low, brittle, and it is easy to cut off the plate. If the printing pressure is too high and the machine speed is fast, it will be more likely to break the plate.
7. Partially dropped. After the roughening of the electrolysis, the gray quality of the printing plate base is not completely removed, and the partial photosensitive layer is not strongly adsorbed. Printing hundreds or thousands of sheets may partially print out.
8. Locally out of print. Before the application of the photosensitive liquid, the layout was not cleaned, leaving traces of acid flow when hanging, resulting in partial plate-off.
9. PS plate surface roughness is not good, coarse sand, too thin. Abrasives are too thick, water capacity is insufficient, easy to dirty; fine sand eyes, the photosensitive film in the microporous is not easy to clean, the base is easy to pollution, easy to stain on printing.
10. PS version of ink affinity, poor alkali resistance. Sensitizer deteriorated due to failure.
11. Improper proportion ratio of photosensitizer, such as film-forming agent content is too low, sensitivity declines, and resistance to printing force is low. If the content of the photosensitive resin is too low, the wear resistance and alkali resistance of the photosensitive layer will be reduced, and such a PS plate has low resistance to printing.
12. The photosensitive film is too thin, and the alkaline developing solution easily damages the oxide film during development. When printing on the machine, the printing plate and the blank space are dirty.
PS version body quality problems, in general, the use of manufacturers can not be solved, all they can do is to timely feedback to the manufacturer, prompting the PS version of the quality of the fundamental solution. If the problem cannot be solved, the PS version of other brands and models will have to be re-used. Do not mistake the quality of the PS version for use.
Second, PS version printing quality problems
Shaiban is a "bridge" process in platemaking and printing. Its status is very important. Although the PS plate is easier to handle and the quality is better than that of the flat plate, it often causes troubles in the manufacture of the PS plate. The use of PS version is not satisfactory.
1. The image is imaginary and dirty. 1 The tape is too close to the image on the tape, the image pad is imaginary, and there is dirty printing on the tape; when the imposition is made, the bases overlap, the image pad is imaginary, and sometimes there are dirty marks. Solution: Try to keep the proper distance when the tape or imposition sheet is overlapped. Adhesive smears can be removed with a dirt remover or removed with a diffuse film double exposure method. 2During printing, there are dust, sand, and other dirt on the PS plate, causing the image to be dirty on the pad. Therefore, you must carefully check the layout before the printing, remove all the dust, do a good job of indoor health, the best is to print in a dust-free environment. 3 When printing, the glass is not clean. There are glue points to dirty the image pad. According to the operating process requirements, the glass must be wiped clean before printing, otherwise it is not allowed to print. 4 Shaiban vacuum pump performance is poor, lack of vacuum, the contact between the plate and the film is not true, causing sun drying. The treatment method is to overhaul the vacuum pump, and the vacuum degree must be more than 0.08 MPa. 5 The air chamber of the printing machine has a poor airtightness and leaks, making it inspiratory. Printing plates are often sunburned due to aging of the gums and should be replaced or glued. 6 The bottom of the printing plate is uneven and the suction is not uniform. The contact between the partial film and the PS plate is not real. There are three ways to solve this problem: First, check if the bottom of the printing plate is uneven and flatten it when uneven. Second, select the porous wool pad to promote the contact between the PS plate and the film. Third, use the second suction method, that is, the first time. Suction stops releasing part of the gas, and then inhales again, which promotes close and even contact between the PS plate and the film. 7 film image density is not enough, when the print version is light through, the image is exposed, causing the image to send out of ink. In principle, printing cannot be done when the image density is less than the standard, and it must be re-plated. Sometimes you can try to pull the light far away, so you can reduce or avoid sun drying to a certain extent.
2. The blank part of the plate is dirty. 1 underexposure, resulting in incomplete decomposition of the sensitizer, the development is not completely removed, causing the blank part of the dirty. If the printing plate is not printed on the machine, it can be rescued by the second development method, but this phenomenon is only applicable to underexposure situations, and severe cases cannot be saved. Determining the proper exposure time is the key to determining the quality of the printing plate. With a continuous ash grading test, the 0.45 densitizing without ink absorption will effectively solve the problem of underprinting caused by printing plates. 2 Insufficient development, non-photosensitive film removal is not clean, resulting in dirty plates. The reasons are: insufficient developer concentration; insufficient development time; low developer temperature; ideal development temperature is 22±2°C; The 3PS version of the photosensitive layer is unevenly coated, the thickness is not uniform, and the degree of decomposition of the photosensitive resin during the printing is different, resulting in dingy. If the photosensitive adhesive coated with a centrifugal baking plate machine is often radiated, and the four-sided rubber is easy to be dirty, it can be rescued by local exposure or partial development. 4 Incorrect lifting of the ink on the dirt, the ink can be washed off with turpentine, and the ink is refreshed again. 5 Wipe protection glue is improper, there is a leak in the place, resulting in dirty. 6 In addition to dirty methods cause blank parts dirty. The reason is that: in addition to the amount of dirty agent; repair time is not sufficient; in addition to the dirty agent on the printing plate is not timely rinse and wipe. 7 layout was blue and green. This version can be used in addition to dirty agent to identify, can be removed in addition to dirty agent, it shows underdeveloped or underexposure; if you can not get rid of, then the PS version is not completely sealed, belonging to the quality of the PS version of the body, and The print version is irrelevant and cannot be salvaged. Contact with the manufacturer to resolve it. 8 The plate is light blue after development. This is due to the fact that the plate has been stored for a long time or the temperature at the time of applying the photo resist is too high, which causes oxidation of the aluminum oxide on the surface of the aluminum plate and the photosensitive layer. It is insoluble in the developer and does not cause dinging under normal conditions. It only appears dirty when using dirt remover. This is because the dirt remover dissolves in a bluish color, accumulates in a more color-preserving circle, and becomes dirty after drying. The solution is: wipe the lysate with a damp cloth immediately after it is dirty, and it will not be dirty.
3. Printing plates do not absorb ink. 1 overexposure: the original density is too low, when the print version of light transmission; exposure time is too long; PS version is not properly preserved, light leakage, storage period is too long, deterioration, bad ink absorption. 2 excessive development; developer too concentrated, too strong alkaline; too long development time; developer temperature is too high. According to the different characteristics of different manufacturers of different brands of PS version of the sensitizer, the use of appropriate formulations, matching ratio of the developer, with the test strip detection and control, is an effective way to steadily control the development of quality. 3 The protective glue becomes acid and deteriorates, which often occurs during the high-temperature rainy season. Dirty and dirty, rubber road, causing no ink.
4. The picture is too light. 1 Excessive exposure should reduce exposure time. 2 excessive development, should reduce the development time. 3Insufficient density of the original plate, transmission of light when printing, so that the network damage is reduced. 4 The printer is under-pressurized or has few gaskets. Adjust the pressure or gasket properly. The 5PS version is too coarse and its mesh is damaged and becomes lighter.
5. The graphic is too deep. The reason why the graphic is too deep is often the opposite of the reason that the pattern is too shallow, and the solution is the opposite. 1 underexposure, should increase the exposure time. 2 underdeveloped, should enhance the development time. 3 The original non-graphic part has a high degree of fog, and the transparency is not good, and the exposure time can be appropriately increased. 4 The pressure of the printing press is large or the thickness of the liner is thick. The pressure or the liner should be properly reduced. 5 ink is too thin, too soft. Processing method: Update the ink.
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