In the process of plate making or printing, the positive PS version always produces some faults. In severe cases, it will also affect normal production. In order to promote production and increase production efficiency, in order to improve plate-making quality and printing quality, reduce or avoid the occurrence of some common faults, it is necessary to analyze and deal with them.
The failure of the positive PS version can be divided into the faults in the process of plate making and the faults in the printing process. Here we talk about our experience in these two aspects.
First, common faults, causes and solutions in the plate making process.
1. The image is imaginary
Reasons: (1) The platen machine has poor vacuum performance: 1 The voltage is low or the vacuum pump motor is running out of phase. 2 vacuum pump due to pumping air leakage of water in the air caused by emulsification, resulting in poor lubrication, thereby reducing the degree of vacuum. (2) Sealing room sealing is not good: 1 There is a gap or partial gap between the printing machine and the sealing rubber ring. 2 There are impurities on the sealing rubber ring, which makes the glass and the rubber ring unfavorable. 1 Under the print version, the paper or lining underneath is pressed against the sealing ring. (3) Insufficient density of the film image: 1 The exposure time is short. 2 Short development time or developer aging. (4) Reverse film: film reversal during production or copying or not made according to the printing plate type. (5) The bottom of the air chamber is uneven and the vacuum time is short. There is no absorption between the printing plate and the film when the printing is started. (6) The developer concentration is not appropriate. (7) Development time is too long. (8) The developer was not selected correctly. (9) The individual word lines on the layout are not clear enough. 1 There is a blockage between the film and the layout when printing. 2 When the revision was too close to the graphic or when the remaining dirt remover was touched, a part of the film was removed. (10) creases on the PS plate, resulting in poor adhesion of the film and the layout. (11) The pasted pictures are of different thicknesses, not on the same plane, and the edges are too close to the graphic.
Treatment methods: (l) 1 increase the voltage, make the vacuum pump pumping speed faster, strengthen, connect the lack of power to normal power. 2 Regularly change the vacuum pump lubricating oil. When selecting the lubricating oil, choose a strong water-resistant, not emulsifiable, and also pay attention to check the vacuum time during the printing. (2) 1 for proper adjustment, the screws must be tightly fixed to avoid changes. 2 When printing, check whether there are any debris on the sealing ring. It is better to cover the cover after the printing is done to prevent the entry of impurities. 3 The pad or liner must be placed in the middle when printing, and should not be too close or pressed on the sealing ring. (3) 1 according to the film sensitivity given the correct exposure time, after the density should be 3. O above. 2 Accurately grasp the development time, and the development should be uniform. The developer should be replaced in time for aging. (4) When making the film, attention should be paid to the positive and negative aspects, and the classification of the plate type should be clearly defined. (5) Flatten the bottom and set the vacuum time according to the situation. Under special circumstances, the second suction method can be used to improve the contact performance between the film and the PS plate. (6) The components of the developer should be properly proportioned and should be tested during development to determine the optimal concentration. (7) Develop in a certain or specific time, special treatment in special circumstances. (8) The correct choice of developer, generally less than 60 seconds the use of weak bases, more than 60 seconds more use of strong bases. (9)1 During the printing, care should be taken to check for any debris on the film or on the layout. 2 When wiping the remaining correction paste, wash it with water while scrubbing at non-graphics. (10) If there are serious creases, they should not be used after being treated or treated accordingly. (11) The pictures shall not be overlaid and thickened. Try to keep them on the same plane as much as possible. Even if they are not flat, they should stay away from the graphic.
2. Layout with dirty
Reasons: (l) Incomplete development: 1 Short development time. 2 developer aging. 3 The concentration of developer is not enough. 4 The developer has a low temperature and has not been developed at normal temperature. (2) Uneven coating of photosensitive layer of PS plate. (3) The glass of the printing machine did not wipe. (4) There are dirty marks on the film and the film base. Negative exposure was not used during the printing. (5) The original non-graphic part has a high degree of fogging. (6) The transparent rubber image pasted when the image is impositioned is too close. (7) Water flushing is not complete. (8) There is a hair on the edge of the film. (9) Centrifugal coated photosensitive film, easy to get dirty on all four sides. (10) Caused by improper ink extraction. (11) There are leaks on the surface of the plate. (12) No negative exposure was used. (13) The exposure time is not enough. (14) There is dust on the luminaire and it falls down during the printing process. (15) The viscera is caused by yellowing of the film for too long. (16) Did not reach normal power or the voltage was too low during the printing. (17) Improper selection of PS version. (18) Caused by block or speckle patterns on the layout.
Treatment methods: (l) 1 can use the secondary development method, the development of a certain time. 2Change the developer, should pay attention to the machine liquid than the hand-use period can not be seen as long change, hand exposed more in the air, so that the developer of NaOH and CO2 in the air gradually decompose and make the effect Decline. 3 There should be a suitable proportion of concentration, such as the ratio of mistakes, the use of concentration meter to determine, and use the PS version of the test block to verify before use. 4 General developer temperature is best at 22°C-23°C. According to the formula provided by the manufacturer, attention should also be paid to differences in temperature difference between winter and summer. Such as: the summer developer temperature is easy to increase, the winter is easy to drop, should pay attention to constant temperature. (2) When using the film as evenly as possible, this condition mostly occurs in the old PS version. (3) Check the light or put a white paper under the glass to bring out the dirt and wipe it with alcohol. (4) If the substrate or film is dirty and can not be treated, apply a scattering film to remove dirt. (5) Replace the printing plate or increase the printing time under the allowed conditions. If the film is not fixed enough, it should be fixed. The fuser fluid should be replaced. (6) The paste should be open 1cm away. (7) Wash the PS plate with enough water to prevent the developer containing the resin particles from remaining in the grain. After the plate is dry, it will easily produce spots. (8) Cut off the burr. If the edge of the film cutting tool is not sharp, it should be adjusted or replaced so as not to affect the cutting quality. (9) The partial exposure should be used to fully decompose the surrounding photosensitive film. (10) To properly extract the ink, apply a layer of resin and then the ink to the surface under the wet conditions of the layout. Rinse off the remaining ink, scrape off the moisture, and then apply the gum solution. (11) Inspection should be done after gluing to prevent omissions so as not to cause dirty prints. (12) Films that are not part of the overall copy, under normal conditions require negative exposure. (13) Use a printing plate or a signal bar to determine the time, not the same PS plate or PS plate with different sensitivity, and do the corresponding test. (14) When the printing machine is inactive for a long time, it is necessary to remove the stains on the lamps and then reprint the printing plate. The dust can be fully dropped by several normal printing processes. (15) Use potassium cyanide 1g, water 100ml, use 1 part of the original solution, 4 parts of fresh water to dilute the film. (16) After the lamp reaches normal power, the adjustment of the voltage is not enough to make normal power. (17) When used, the oxidation point should not be used seriously. Even if the oxidation point is not too severe, it should be far away from the graphic. (18) Use as a filter, and do not use it on printing plates.
3. Other faults
Reasons: (1) Too much graphics: 1 Overexposure. 2 over development. 3 Density of the print film is not enough. 4 layout is too coarse, easy to damage outlets. (2) The graphic or dot disappears or becomes smaller: 1 The exposure time is long. 2 The dot printing version of the entire copying system used a negative exposure. 3 The density around some film text or dot is low, and the graphic image becomes smaller after printing. 4PS version film thickness varies. (3) Graphic point hypertrophy: 1 underexposure. 2 Underdeveloped. (4) The color of the layout is not normal: 1 The printing plate is stored for too long. 2 After being exposed to strong light. (5) Color after abnormal baking: baking time is not enough or baking time is too long. (6) The base color is not normal, and the base is not qualified.
Treatment methods: (l) 1 Use a ruler or signal bar to determine the exposure time. 2 Different PS versions have different development times and conditions, and it is best to use the formula provided by the manufacturer. 3 Select the fine grain of the plate to be not easily damaged during development. (2) 1 determine a good exposure time, in advance with the same batch of PS version to do the experiment, but also pay attention to the stability of the light when the printing. The negative exposure is generally not used in the printing of 2 dot printing plates. 3 The old-fashioned laser photo-discharging film has many texts and hairs around the outlets. Attention should be paid when using it. 4 When choosing the printing plate, attention should be paid to the surface quality, and the selection should be made from the aspects of uniform no-spotting and normal color of the film. (3)1 The exposure time is determined according to the conditions of the printing plate, and some changes must be noted. 2 The development should understand the type of developer, the extent of use, temperature conditions and other factors after the development of changes, such as the winter plate temperature is low, it is easy to make the developer temperature drops. (4) 1 It should not be used on screen printing or high-grade printing. If the printing time is long, the quality of the printing plate is poor and the printing plate should be replaced. 2 Care should be taken after development to protect or black ink. (5) Baking version should pay attention to the temperature and time, generally in a constant temperature of 230 °C -250 °C bake 6min-8min, baking plate after the reddish brown is normal. (6) Pay attention to the quality of the base plate when selecting, especially the recycled PS plate base, some metal components are unqualified, and some developed plates have a fluorescent color. Under this condition, the PS plate is very resistant to Indian forces, generally in the l-2 thousand. India. Therefore, it is best not to use when using, so as not to affect the printing quality.
Second, the common faults, causes and treatment methods in the printing process.
1. Easy to paste version
Reasons: (1) Unqualified plate grains and poor water retention. (2) The base quality is not good. (3) The water roller is dirty. (4) Excessive printing pressure. (5) Moisture is not adjusted for ink properties or paper properties. (6) The viscosity of the ink is too high. (7) The ink is too thin. (8) The water roller is improperly adjusted or the force acting on the layout is too small. (9) The amount of ink transferred is too large to allow water to supply. (10) There are too many other additives in the ink. (11) The ink dries too quickly.
Treatment methods: (1) Select a good sand spot, especially for the old PS plate selection should be strict, after the plate-making observation with a magnifying glass to see the situation of its sand. (2) If the base metal component of the plate is unqualified, it is easy to damage the grains when printing, and it is best to avoid using it. (3) Care should be taken to clean the water roller, and it cannot be mistaken for other causes. (4) Pressure is one of the factors that affect the balance of ink and ink, and it is generally within the range of 0.10 to 0.15mm when printing. (5) The amount of cyan ink is large and the amount of wading water is properly adjusted. Black ink and other small amounts of water should be given less moisture. If the paper and rough surface have a large amount of wading water, and the water content is appropriately increased, if the surface is smooth and the amount of water is small, the moisture content should be appropriately reduced. (6) The ink should have certain printability, and the viscosity should be diluted. If it is degraded due to improper storage, it should not be used. (7) The tension of the ink during printing should be stable and should not be too thin, and should be determined in light of the conditions of ink transfer, glossiness, and enlargement of graphic points. (8) The printing machine with two printing water rollers should generally be light and heavy. The force between the water roller and the water roller should be less than the force of the water roller and printing plate. The water transfer roller should be parallel to the outlet roller. . (9) The amount of ink transfer should follow the principle of water-ink balance, not too large, the amount of ink transferred is too easy to emulsify, resulting in insufficient water supply, so easy paste version.
2. Plate with dirty
Reasons: (1) Incomplete revision. (2) There are scratches or severe oxidation spots on the substrate. (3) Insufficient stencil or underdeveloped to form a shadow at the blank of the printing plate. (4) The water roller is heavily dirty, resulting in irregular sticking or partial dirtiness. (5) The ink is thin and emulsified seriously. (6) There is a leak in the glue. (7) Abrasive roughness is large. (8) Plate base wear resistance is poor. (9) There is debris in the paper when printing, scratch the layout, such as: sand.
Treatment methods: (1) When revisions are made, revision patches with low efficacy should not be used. Even if they are used, revision time should be increased to avoid incomplete revision. (2) Replace the plate. (3) Underexposure should not be used, underdeveloped can be developed again. (4) Pay attention to the cleaning roller, especially one of the two lower rollers in the plate roller. (5) The ink should be diluted for dilution. The dilution should be generally no more than 15% of its volume. The diluted ink should be strictly controlled when printed. (6) Drainage can also be lightly developed to remove dirt that has been absorbed in the sand. (7) Observe the sand spot with a magnifying glass. The sand spot should be fine and sharp. (8) There is a quality problem in the base plate, which can easily damage the sand and should not be used. (9) The condition of the paper should be known at the time of printing. If there is sand in the paper, it should not be used for printing.
3. Bad on the plate
Reasons: (1) Over-developed. (2) The density of the printing film is not enough. (3) Exposure
The failure of the positive PS version can be divided into the faults in the process of plate making and the faults in the printing process. Here we talk about our experience in these two aspects.
First, common faults, causes and solutions in the plate making process.
1. The image is imaginary
Reasons: (1) The platen machine has poor vacuum performance: 1 The voltage is low or the vacuum pump motor is running out of phase. 2 vacuum pump due to pumping air leakage of water in the air caused by emulsification, resulting in poor lubrication, thereby reducing the degree of vacuum. (2) Sealing room sealing is not good: 1 There is a gap or partial gap between the printing machine and the sealing rubber ring. 2 There are impurities on the sealing rubber ring, which makes the glass and the rubber ring unfavorable. 1 Under the print version, the paper or lining underneath is pressed against the sealing ring. (3) Insufficient density of the film image: 1 The exposure time is short. 2 Short development time or developer aging. (4) Reverse film: film reversal during production or copying or not made according to the printing plate type. (5) The bottom of the air chamber is uneven and the vacuum time is short. There is no absorption between the printing plate and the film when the printing is started. (6) The developer concentration is not appropriate. (7) Development time is too long. (8) The developer was not selected correctly. (9) The individual word lines on the layout are not clear enough. 1 There is a blockage between the film and the layout when printing. 2 When the revision was too close to the graphic or when the remaining dirt remover was touched, a part of the film was removed. (10) creases on the PS plate, resulting in poor adhesion of the film and the layout. (11) The pasted pictures are of different thicknesses, not on the same plane, and the edges are too close to the graphic.
Treatment methods: (l) 1 increase the voltage, make the vacuum pump pumping speed faster, strengthen, connect the lack of power to normal power. 2 Regularly change the vacuum pump lubricating oil. When selecting the lubricating oil, choose a strong water-resistant, not emulsifiable, and also pay attention to check the vacuum time during the printing. (2) 1 for proper adjustment, the screws must be tightly fixed to avoid changes. 2 When printing, check whether there are any debris on the sealing ring. It is better to cover the cover after the printing is done to prevent the entry of impurities. 3 The pad or liner must be placed in the middle when printing, and should not be too close or pressed on the sealing ring. (3) 1 according to the film sensitivity given the correct exposure time, after the density should be 3. O above. 2 Accurately grasp the development time, and the development should be uniform. The developer should be replaced in time for aging. (4) When making the film, attention should be paid to the positive and negative aspects, and the classification of the plate type should be clearly defined. (5) Flatten the bottom and set the vacuum time according to the situation. Under special circumstances, the second suction method can be used to improve the contact performance between the film and the PS plate. (6) The components of the developer should be properly proportioned and should be tested during development to determine the optimal concentration. (7) Develop in a certain or specific time, special treatment in special circumstances. (8) The correct choice of developer, generally less than 60 seconds the use of weak bases, more than 60 seconds more use of strong bases. (9)1 During the printing, care should be taken to check for any debris on the film or on the layout. 2 When wiping the remaining correction paste, wash it with water while scrubbing at non-graphics. (10) If there are serious creases, they should not be used after being treated or treated accordingly. (11) The pictures shall not be overlaid and thickened. Try to keep them on the same plane as much as possible. Even if they are not flat, they should stay away from the graphic.
2. Layout with dirty
Reasons: (l) Incomplete development: 1 Short development time. 2 developer aging. 3 The concentration of developer is not enough. 4 The developer has a low temperature and has not been developed at normal temperature. (2) Uneven coating of photosensitive layer of PS plate. (3) The glass of the printing machine did not wipe. (4) There are dirty marks on the film and the film base. Negative exposure was not used during the printing. (5) The original non-graphic part has a high degree of fogging. (6) The transparent rubber image pasted when the image is impositioned is too close. (7) Water flushing is not complete. (8) There is a hair on the edge of the film. (9) Centrifugal coated photosensitive film, easy to get dirty on all four sides. (10) Caused by improper ink extraction. (11) There are leaks on the surface of the plate. (12) No negative exposure was used. (13) The exposure time is not enough. (14) There is dust on the luminaire and it falls down during the printing process. (15) The viscera is caused by yellowing of the film for too long. (16) Did not reach normal power or the voltage was too low during the printing. (17) Improper selection of PS version. (18) Caused by block or speckle patterns on the layout.
Treatment methods: (l) 1 can use the secondary development method, the development of a certain time. 2Change the developer, should pay attention to the machine liquid than the hand-use period can not be seen as long change, hand exposed more in the air, so that the developer of NaOH and CO2 in the air gradually decompose and make the effect Decline. 3 There should be a suitable proportion of concentration, such as the ratio of mistakes, the use of concentration meter to determine, and use the PS version of the test block to verify before use. 4 General developer temperature is best at 22°C-23°C. According to the formula provided by the manufacturer, attention should also be paid to differences in temperature difference between winter and summer. Such as: the summer developer temperature is easy to increase, the winter is easy to drop, should pay attention to constant temperature. (2) When using the film as evenly as possible, this condition mostly occurs in the old PS version. (3) Check the light or put a white paper under the glass to bring out the dirt and wipe it with alcohol. (4) If the substrate or film is dirty and can not be treated, apply a scattering film to remove dirt. (5) Replace the printing plate or increase the printing time under the allowed conditions. If the film is not fixed enough, it should be fixed. The fuser fluid should be replaced. (6) The paste should be open 1cm away. (7) Wash the PS plate with enough water to prevent the developer containing the resin particles from remaining in the grain. After the plate is dry, it will easily produce spots. (8) Cut off the burr. If the edge of the film cutting tool is not sharp, it should be adjusted or replaced so as not to affect the cutting quality. (9) The partial exposure should be used to fully decompose the surrounding photosensitive film. (10) To properly extract the ink, apply a layer of resin and then the ink to the surface under the wet conditions of the layout. Rinse off the remaining ink, scrape off the moisture, and then apply the gum solution. (11) Inspection should be done after gluing to prevent omissions so as not to cause dirty prints. (12) Films that are not part of the overall copy, under normal conditions require negative exposure. (13) Use a printing plate or a signal bar to determine the time, not the same PS plate or PS plate with different sensitivity, and do the corresponding test. (14) When the printing machine is inactive for a long time, it is necessary to remove the stains on the lamps and then reprint the printing plate. The dust can be fully dropped by several normal printing processes. (15) Use potassium cyanide 1g, water 100ml, use 1 part of the original solution, 4 parts of fresh water to dilute the film. (16) After the lamp reaches normal power, the adjustment of the voltage is not enough to make normal power. (17) When used, the oxidation point should not be used seriously. Even if the oxidation point is not too severe, it should be far away from the graphic. (18) Use as a filter, and do not use it on printing plates.
3. Other faults
Reasons: (1) Too much graphics: 1 Overexposure. 2 over development. 3 Density of the print film is not enough. 4 layout is too coarse, easy to damage outlets. (2) The graphic or dot disappears or becomes smaller: 1 The exposure time is long. 2 The dot printing version of the entire copying system used a negative exposure. 3 The density around some film text or dot is low, and the graphic image becomes smaller after printing. 4PS version film thickness varies. (3) Graphic point hypertrophy: 1 underexposure. 2 Underdeveloped. (4) The color of the layout is not normal: 1 The printing plate is stored for too long. 2 After being exposed to strong light. (5) Color after abnormal baking: baking time is not enough or baking time is too long. (6) The base color is not normal, and the base is not qualified.
Treatment methods: (l) 1 Use a ruler or signal bar to determine the exposure time. 2 Different PS versions have different development times and conditions, and it is best to use the formula provided by the manufacturer. 3 Select the fine grain of the plate to be not easily damaged during development. (2) 1 determine a good exposure time, in advance with the same batch of PS version to do the experiment, but also pay attention to the stability of the light when the printing. The negative exposure is generally not used in the printing of 2 dot printing plates. 3 The old-fashioned laser photo-discharging film has many texts and hairs around the outlets. Attention should be paid when using it. 4 When choosing the printing plate, attention should be paid to the surface quality, and the selection should be made from the aspects of uniform no-spotting and normal color of the film. (3)1 The exposure time is determined according to the conditions of the printing plate, and some changes must be noted. 2 The development should understand the type of developer, the extent of use, temperature conditions and other factors after the development of changes, such as the winter plate temperature is low, it is easy to make the developer temperature drops. (4) 1 It should not be used on screen printing or high-grade printing. If the printing time is long, the quality of the printing plate is poor and the printing plate should be replaced. 2 Care should be taken after development to protect or black ink. (5) Baking version should pay attention to the temperature and time, generally in a constant temperature of 230 °C -250 °C bake 6min-8min, baking plate after the reddish brown is normal. (6) Pay attention to the quality of the base plate when selecting, especially the recycled PS plate base, some metal components are unqualified, and some developed plates have a fluorescent color. Under this condition, the PS plate is very resistant to Indian forces, generally in the l-2 thousand. India. Therefore, it is best not to use when using, so as not to affect the printing quality.
Second, the common faults, causes and treatment methods in the printing process.
1. Easy to paste version
Reasons: (1) Unqualified plate grains and poor water retention. (2) The base quality is not good. (3) The water roller is dirty. (4) Excessive printing pressure. (5) Moisture is not adjusted for ink properties or paper properties. (6) The viscosity of the ink is too high. (7) The ink is too thin. (8) The water roller is improperly adjusted or the force acting on the layout is too small. (9) The amount of ink transferred is too large to allow water to supply. (10) There are too many other additives in the ink. (11) The ink dries too quickly.
Treatment methods: (1) Select a good sand spot, especially for the old PS plate selection should be strict, after the plate-making observation with a magnifying glass to see the situation of its sand. (2) If the base metal component of the plate is unqualified, it is easy to damage the grains when printing, and it is best to avoid using it. (3) Care should be taken to clean the water roller, and it cannot be mistaken for other causes. (4) Pressure is one of the factors that affect the balance of ink and ink, and it is generally within the range of 0.10 to 0.15mm when printing. (5) The amount of cyan ink is large and the amount of wading water is properly adjusted. Black ink and other small amounts of water should be given less moisture. If the paper and rough surface have a large amount of wading water, and the water content is appropriately increased, if the surface is smooth and the amount of water is small, the moisture content should be appropriately reduced. (6) The ink should have certain printability, and the viscosity should be diluted. If it is degraded due to improper storage, it should not be used. (7) The tension of the ink during printing should be stable and should not be too thin, and should be determined in light of the conditions of ink transfer, glossiness, and enlargement of graphic points. (8) The printing machine with two printing water rollers should generally be light and heavy. The force between the water roller and the water roller should be less than the force of the water roller and printing plate. The water transfer roller should be parallel to the outlet roller. . (9) The amount of ink transfer should follow the principle of water-ink balance, not too large, the amount of ink transferred is too easy to emulsify, resulting in insufficient water supply, so easy paste version.
2. Plate with dirty
Reasons: (1) Incomplete revision. (2) There are scratches or severe oxidation spots on the substrate. (3) Insufficient stencil or underdeveloped to form a shadow at the blank of the printing plate. (4) The water roller is heavily dirty, resulting in irregular sticking or partial dirtiness. (5) The ink is thin and emulsified seriously. (6) There is a leak in the glue. (7) Abrasive roughness is large. (8) Plate base wear resistance is poor. (9) There is debris in the paper when printing, scratch the layout, such as: sand.
Treatment methods: (1) When revisions are made, revision patches with low efficacy should not be used. Even if they are used, revision time should be increased to avoid incomplete revision. (2) Replace the plate. (3) Underexposure should not be used, underdeveloped can be developed again. (4) Pay attention to the cleaning roller, especially one of the two lower rollers in the plate roller. (5) The ink should be diluted for dilution. The dilution should be generally no more than 15% of its volume. The diluted ink should be strictly controlled when printed. (6) Drainage can also be lightly developed to remove dirt that has been absorbed in the sand. (7) Observe the sand spot with a magnifying glass. The sand spot should be fine and sharp. (8) There is a quality problem in the base plate, which can easily damage the sand and should not be used. (9) The condition of the paper should be known at the time of printing. If there is sand in the paper, it should not be used for printing.
3. Bad on the plate
Reasons: (1) Over-developed. (2) The density of the printing film is not enough. (3) Exposure
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