7. What factors can cause soiling on the PS plate is mainly due to two factors:
1 There are dirt particles or dust and other foreign particles on the print glass and on the film.
2 hand-made collage of small negative film edge, transparent adhesive tape edge marks.
8. How to deal with the different parts of the PS plate, how different the method 1 If there is excess light block material on the site of the plate, because the actual site of the film is completely opaque, so does not affect the quality of the printing plate.
2 If the extra light blocking material appears on the dot site. Or on the ground, the borders between lines and blanks will leave dirt in these places. If the dirt removal agent is used, it is unavoidable to remove the image and text, so it can only be scraped with a scraper and the effect is naturally not good. If the dirt is serious, the plate can only be scrapped.
3 If the dirty spots appear in the blank area and there is a certain distance from the graphic area, it can be removed by removing the dirty agent.
Therefore, before the exposure of the printing plate, we must carefully check the position of the dot and the border between the graphic and the blank to ensure that no dirt occurs. When manually making the imprint, ensure that the edge of the negative and the adhesive tape do not appear on this part.
9. There are several ways to remove dirt from the PS plate during the printing process. When using the PS plate, be aware that there are two problems: the PS plate in addition to the dirty membrane and the dirty membrane in addition to the dirty membrane.
(1) The scattering membrane removal method utilizes a scattering film to scatter light during printing, so that the photosensitive material corresponding to the small stains and stains on the plate is irradiated with scattered light from various directions to remove dirt. This method will affect the reproduction of fine lines in the dots and graphics, thus affecting the quality of printed products. Therefore, the layout of the original with dots and thin lines, generally can not use this dirty method.
When printing text-only books and periodicals, it is common to output single-page negatives, and then collage on the transparent large-format basis. Exposure in the ordinary way, after development, there will be dirty marks around the single-page negative film and corresponding parts of the adhesive tape on the printing plate. It takes a lot of time to remove dirt with the dirty agent method, and use the diffusion film to remove dirt. More effective.
The method for removing the dirty film is to divide the exposure into two times, the first is the main exposure, without the diffusion film, and the exposure time is about 4/5 of the normal exposure time; after the completion, the diffusion film is applied for the second time. In the sub-exposure, the exposure time is about 1/2 of the main exposure.
There are no or few dirty marks and fine spots around the PS plate, the small backsheet, and the adhesive tape that have been dried out in this way.
2 In addition to the dirty agent, the dirty method is to remove the dirt with a dirt remover that can dissolve the PS plate photosensitive coating. For the positive PS type and negative PS type, the corresponding dirt remover is used separately to remove dirt.
In addition to the dirty agent in addition to the dirty operation method is: After the plate is developed, remove the dirt agent with a brush, wipe the dirty spots and marks on the plate. Be careful not to let the dirt remover hit the graphic part of the plate or allow the dirt remover to penetrate into the graphic part. After removing the dirty, quickly remove the residual detergent and dissolved photosensitive material on the plate with water.
In addition to the benzene substances contained in the dirty agent, in addition to dirty operation should pay attention to the ventilation of the operating environment, try to avoid inhaling benzene substances or reduce the amount of benzene intake. In addition to the solvent in the dirty agent volatile, pay attention to the seal.
10. What is the usefulness of the baking plate? The PS plate is based on the unseen light-sensitive layer as a graphic basis. This photo-sensitive layer still has photosensitivity, and the resistance to alkali after light is poor. After baking treatment, the molecular structure of the photosensitive layer can be changed from linear to reticulate. Loss of photosensitivity, thus enhancing the stability, corrosion resistance, and mechanical strength of the graphic part, greatly improving the printing plate's resistance to printing.
Whether you need to bake version depends on the number of prints. In general, printings with less than 50,000 impressions can be printed on the PS plate in the usual way. This does not require additional baking process. Because the photosensitive layer of the dirty parts after baking will be cross-linked and solidified, it can no longer be dissolved in the dirt removing agent and cannot be revised. Therefore, the baking must be performed after thoroughly removing the dirt. Printing drying board common problems and solutions of three What are the reasons that may cause the image to be bloated? As long as the photosensitive film of the film and the Ps plate does not adhere well, the phenomenon of image blemishes may occur. This is for the field and the thicker lines. The influence of the text is not great, but it will have a serious impact on dot and thin lines and small text. The common sun causes are as follows:
1 Shaiban vacuum pump power is not enough, the printing frame is not sealed, the air hole is blocked or the pumping time is improperly set, which causes poor pumping; the pressure drop in the frame is not enough, and the photosensitive film of the film and the PS plate cannot be tightly connected.
2 When the film, light-blocking paper or printing plate is placed, it is not careful, and some of them are exposed outside the printing machine, which affects the seal of the printing frame and causes decompression.
3 There is sand or other impurities between the film and the printing plate; the edge of the film that is hand-picked is not cut cleanly; the edge of the tape paper or the two films overlaps, and the film in the local position is not closely connected with the photosensitive coating of the Ps plate.
4Because the surface is smooth, between the PS plate and the original plate, the surrounding air may be tightly drawn first, and the middle air is sealed because it has been sealed around, so that the middle plate does not adhere to the photosensitive layer of the plate. Therefore, the phenomenon of sun drying appeared. The solution is to use the second pumping method and divide the pumping into two steps. When pumping for the first time, if the pumping is not uniform, interference pattern can be seen. At this time, pumping should be stopped, and the air that is not drawn between the negative and the printing plate will be diffused to the surrounding due to the relatively high pressure and destroy the surrounding area. In the sealed state, after the interference pattern has disappeared, a second pumping operation is performed immediately. After two times of evacuation, the phenomenon of hair deficiencies caused by uneven pumping can be eliminated. Some stencils are automatically evacuated twice.
2. What is the effect of the developer concentration on the development quality? The higher the developer concentration, the faster the development speed. However, when the concentration is too high, the developer may also have a dissolving effect on the photosensitive layer that is not visible in the graphic part, resulting in poor printing plate printing. The outlets became smaller and the resistance to printing decreased.
The lower the developer concentration, the slower the development speed. When the developer concentration is too low, the development will be incomplete, the blank will have a blue background, and the full version will be dirty when printed. When this happens, for plates that are not very demanding, they can be redeveloped after adding new developer. (To be continued)
1 There are dirt particles or dust and other foreign particles on the print glass and on the film.
2 hand-made collage of small negative film edge, transparent adhesive tape edge marks.
8. How to deal with the different parts of the PS plate, how different the method 1 If there is excess light block material on the site of the plate, because the actual site of the film is completely opaque, so does not affect the quality of the printing plate.
2 If the extra light blocking material appears on the dot site. Or on the ground, the borders between lines and blanks will leave dirt in these places. If the dirt removal agent is used, it is unavoidable to remove the image and text, so it can only be scraped with a scraper and the effect is naturally not good. If the dirt is serious, the plate can only be scrapped.
3 If the dirty spots appear in the blank area and there is a certain distance from the graphic area, it can be removed by removing the dirty agent.
Therefore, before the exposure of the printing plate, we must carefully check the position of the dot and the border between the graphic and the blank to ensure that no dirt occurs. When manually making the imprint, ensure that the edge of the negative and the adhesive tape do not appear on this part.
9. There are several ways to remove dirt from the PS plate during the printing process. When using the PS plate, be aware that there are two problems: the PS plate in addition to the dirty membrane and the dirty membrane in addition to the dirty membrane.
(1) The scattering membrane removal method utilizes a scattering film to scatter light during printing, so that the photosensitive material corresponding to the small stains and stains on the plate is irradiated with scattered light from various directions to remove dirt. This method will affect the reproduction of fine lines in the dots and graphics, thus affecting the quality of printed products. Therefore, the layout of the original with dots and thin lines, generally can not use this dirty method.
When printing text-only books and periodicals, it is common to output single-page negatives, and then collage on the transparent large-format basis. Exposure in the ordinary way, after development, there will be dirty marks around the single-page negative film and corresponding parts of the adhesive tape on the printing plate. It takes a lot of time to remove dirt with the dirty agent method, and use the diffusion film to remove dirt. More effective.
The method for removing the dirty film is to divide the exposure into two times, the first is the main exposure, without the diffusion film, and the exposure time is about 4/5 of the normal exposure time; after the completion, the diffusion film is applied for the second time. In the sub-exposure, the exposure time is about 1/2 of the main exposure.
There are no or few dirty marks and fine spots around the PS plate, the small backsheet, and the adhesive tape that have been dried out in this way.
2 In addition to the dirty agent, the dirty method is to remove the dirt with a dirt remover that can dissolve the PS plate photosensitive coating. For the positive PS type and negative PS type, the corresponding dirt remover is used separately to remove dirt.
In addition to the dirty agent in addition to the dirty operation method is: After the plate is developed, remove the dirt agent with a brush, wipe the dirty spots and marks on the plate. Be careful not to let the dirt remover hit the graphic part of the plate or allow the dirt remover to penetrate into the graphic part. After removing the dirty, quickly remove the residual detergent and dissolved photosensitive material on the plate with water.
In addition to the benzene substances contained in the dirty agent, in addition to dirty operation should pay attention to the ventilation of the operating environment, try to avoid inhaling benzene substances or reduce the amount of benzene intake. In addition to the solvent in the dirty agent volatile, pay attention to the seal.
10. What is the usefulness of the baking plate? The PS plate is based on the unseen light-sensitive layer as a graphic basis. This photo-sensitive layer still has photosensitivity, and the resistance to alkali after light is poor. After baking treatment, the molecular structure of the photosensitive layer can be changed from linear to reticulate. Loss of photosensitivity, thus enhancing the stability, corrosion resistance, and mechanical strength of the graphic part, greatly improving the printing plate's resistance to printing.
Whether you need to bake version depends on the number of prints. In general, printings with less than 50,000 impressions can be printed on the PS plate in the usual way. This does not require additional baking process. Because the photosensitive layer of the dirty parts after baking will be cross-linked and solidified, it can no longer be dissolved in the dirt removing agent and cannot be revised. Therefore, the baking must be performed after thoroughly removing the dirt. Printing drying board common problems and solutions of three What are the reasons that may cause the image to be bloated? As long as the photosensitive film of the film and the Ps plate does not adhere well, the phenomenon of image blemishes may occur. This is for the field and the thicker lines. The influence of the text is not great, but it will have a serious impact on dot and thin lines and small text. The common sun causes are as follows:
1 Shaiban vacuum pump power is not enough, the printing frame is not sealed, the air hole is blocked or the pumping time is improperly set, which causes poor pumping; the pressure drop in the frame is not enough, and the photosensitive film of the film and the PS plate cannot be tightly connected.
2 When the film, light-blocking paper or printing plate is placed, it is not careful, and some of them are exposed outside the printing machine, which affects the seal of the printing frame and causes decompression.
3 There is sand or other impurities between the film and the printing plate; the edge of the film that is hand-picked is not cut cleanly; the edge of the tape paper or the two films overlaps, and the film in the local position is not closely connected with the photosensitive coating of the Ps plate.
4Because the surface is smooth, between the PS plate and the original plate, the surrounding air may be tightly drawn first, and the middle air is sealed because it has been sealed around, so that the middle plate does not adhere to the photosensitive layer of the plate. Therefore, the phenomenon of sun drying appeared. The solution is to use the second pumping method and divide the pumping into two steps. When pumping for the first time, if the pumping is not uniform, interference pattern can be seen. At this time, pumping should be stopped, and the air that is not drawn between the negative and the printing plate will be diffused to the surrounding due to the relatively high pressure and destroy the surrounding area. In the sealed state, after the interference pattern has disappeared, a second pumping operation is performed immediately. After two times of evacuation, the phenomenon of hair deficiencies caused by uneven pumping can be eliminated. Some stencils are automatically evacuated twice.
2. What is the effect of the developer concentration on the development quality? The higher the developer concentration, the faster the development speed. However, when the concentration is too high, the developer may also have a dissolving effect on the photosensitive layer that is not visible in the graphic part, resulting in poor printing plate printing. The outlets became smaller and the resistance to printing decreased.
The lower the developer concentration, the slower the development speed. When the developer concentration is too low, the development will be incomplete, the blank will have a blue background, and the full version will be dirty when printed. When this happens, for plates that are not very demanding, they can be redeveloped after adding new developer. (To be continued)
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