No matter how high the print quality is today, ink fading sometimes remains a problem. Our R&D engineers have considered how to further improve quality issues, and they also found solutions.
Prior to this, Roland 700 ink supply device has already had the ability to ensure stable printing. Including the stepless adjustable horizontal stroke of the ink roller, adjustable ink on the “job†of the printing roller, and most importantly, it can be controlled from the center of the PECOM printing machine, changing the ink at an angle increment of 30 degrees. The starting angle of the ink in the roller.
A large number of tests were conducted to determine the impact parameters that minimize ink fading. As a result, it was found that only the ink oscillating roller directly in contact with the stencil roll had a significant effect on ink fading. The improvements made here have halved the density of the ink on the printed sheet, which is very light and barely visible to the naked eye.
Modern printing presses, such as the Roland 700, have reliable engineering and advanced control and adjustment techniques to suit the highest requirements. However, the problem of density changes on printed sheets may occasionally appear in some special cases. To this end, manroland's R&D engineers were instructed to examine the parameters that affect ink fading. We have been able to change the initial ink jetting angle of the ink fountain roller from the PECOM press center to reduce the ink fading phenomenon, but the purpose of the task is to determine the cause and related factors, thus providing new possibilities for improving the printing effect.
What is Ink Fade "Ink Fade" is the industry term for the change in ink stamping. The word "fade" is used because it usually happens that the ink at the end of the image has a lower density than the front end.
Causes of ink fading?
In the circumferential direction of the plate cylinder, the graphic and non-graphical parts are irregularly distributed. At the same time, the non-printing roller gap also has an effect. Cross-inking affects ink fading.
How the irregularly distributed graphic and non-graphical portions cause ink fading can be explained as follows: The ink roller of the ink supply device forms an ink storage reservoir, which is constantly replenished from the ink fountain by a metering member and an ink roller. The relatively high amount of ink stored in the ink supply device in the ink supply device compensates for the irregular effects described above through the ink passage and a certain width of the ink string.
The printing ink is transferred to the graphic portion of the printing plate by the printing roller. Depending on how much the ink roller "storage" is, more or less ink is transferred to the plate and transferred from the plate to the substrate through the blanket.
Therefore, the following effect occurs: Whenever the non-graphic area does not take ink from the "ink bank," the amount of ink on the ink roller increases. When the printing area is covered with ink, the amount of ink on the ink roller is reduced. The plate cylinder gap forms a relatively large non-graphic area. This results in a “sawtooth†shape in the ink: the ink at the beginning of the print is slightly higher, while the ink at the end of the print is slightly lower.
The design of the transverse cross-inking in the ink supply device can make the ink distribution characteristics on the ink roller smooth, and thus helps to prevent ghosting. However, this necessary and popular feature also has side effects - stringing inks affect ink fading. The printer knows this, because adjusting the starting angle of the ink string will bring about a big change in the degree and development of ink fading, but the exact cause of this effect has never been clarified previously, at least we are concerned about the fading of the ink on the ink. The explanation of the impact is still unknown.
Influencing variables for ink fading include:
The distribution of printed and blank parts on the periphery of the roller, and the image, in addition, do not depend on the quality of the ink used. For example, the ink fountain roller serially inks the starting angle of the entire distance of the series of strokes, such as when the lateral movement is started, the position of the ink fountain roller relative to the pressure printing cylinder is for preventing or minimizing ink fading. Of course, we can only change the variables that can change, and it will not lead to the quality of other important areas.
Which influence variables can be changed?
The image cannot be changed. After all, the printer can print hard-to-print jobs without any problems. The possibility of changing the nature of the ink is often limited. Ink properties are generally determined primarily by properties such as gloss or print characteristics. There is little preference for inks that do not tend to fade.
The range of ink stringing is very limited. This is because serial ink implements many essential tasks. One of the points is that the metering elements, such as ink spoons, make the different ink zones horizontally uniform (30 mm wide on manroland sheet-fed offset printing presses). However, the main task of ink stringing is to eliminate the fluctuation of ink supply on the printing roller produced by the image, that is, to generate ghost images. This is the most important task, requiring a certain length of ink stroke, so that there is only a small change here.
The greatest possibility of effective change is provided by the initial angle of ink jetting, which is the best method to eliminate ink fading that has been adopted in the past, and it has the advantage that there is no worthy “side effect†of the adjustment here. (To be continued)
Prior to this, Roland 700 ink supply device has already had the ability to ensure stable printing. Including the stepless adjustable horizontal stroke of the ink roller, adjustable ink on the “job†of the printing roller, and most importantly, it can be controlled from the center of the PECOM printing machine, changing the ink at an angle increment of 30 degrees. The starting angle of the ink in the roller.
A large number of tests were conducted to determine the impact parameters that minimize ink fading. As a result, it was found that only the ink oscillating roller directly in contact with the stencil roll had a significant effect on ink fading. The improvements made here have halved the density of the ink on the printed sheet, which is very light and barely visible to the naked eye.
Modern printing presses, such as the Roland 700, have reliable engineering and advanced control and adjustment techniques to suit the highest requirements. However, the problem of density changes on printed sheets may occasionally appear in some special cases. To this end, manroland's R&D engineers were instructed to examine the parameters that affect ink fading. We have been able to change the initial ink jetting angle of the ink fountain roller from the PECOM press center to reduce the ink fading phenomenon, but the purpose of the task is to determine the cause and related factors, thus providing new possibilities for improving the printing effect.
What is Ink Fade "Ink Fade" is the industry term for the change in ink stamping. The word "fade" is used because it usually happens that the ink at the end of the image has a lower density than the front end.
Causes of ink fading?
In the circumferential direction of the plate cylinder, the graphic and non-graphical parts are irregularly distributed. At the same time, the non-printing roller gap also has an effect. Cross-inking affects ink fading.
How the irregularly distributed graphic and non-graphical portions cause ink fading can be explained as follows: The ink roller of the ink supply device forms an ink storage reservoir, which is constantly replenished from the ink fountain by a metering member and an ink roller. The relatively high amount of ink stored in the ink supply device in the ink supply device compensates for the irregular effects described above through the ink passage and a certain width of the ink string.
The printing ink is transferred to the graphic portion of the printing plate by the printing roller. Depending on how much the ink roller "storage" is, more or less ink is transferred to the plate and transferred from the plate to the substrate through the blanket.
Therefore, the following effect occurs: Whenever the non-graphic area does not take ink from the "ink bank," the amount of ink on the ink roller increases. When the printing area is covered with ink, the amount of ink on the ink roller is reduced. The plate cylinder gap forms a relatively large non-graphic area. This results in a “sawtooth†shape in the ink: the ink at the beginning of the print is slightly higher, while the ink at the end of the print is slightly lower.
The design of the transverse cross-inking in the ink supply device can make the ink distribution characteristics on the ink roller smooth, and thus helps to prevent ghosting. However, this necessary and popular feature also has side effects - stringing inks affect ink fading. The printer knows this, because adjusting the starting angle of the ink string will bring about a big change in the degree and development of ink fading, but the exact cause of this effect has never been clarified previously, at least we are concerned about the fading of the ink on the ink. The explanation of the impact is still unknown.
Influencing variables for ink fading include:
The distribution of printed and blank parts on the periphery of the roller, and the image, in addition, do not depend on the quality of the ink used. For example, the ink fountain roller serially inks the starting angle of the entire distance of the series of strokes, such as when the lateral movement is started, the position of the ink fountain roller relative to the pressure printing cylinder is for preventing or minimizing ink fading. Of course, we can only change the variables that can change, and it will not lead to the quality of other important areas.
Which influence variables can be changed?
The image cannot be changed. After all, the printer can print hard-to-print jobs without any problems. The possibility of changing the nature of the ink is often limited. Ink properties are generally determined primarily by properties such as gloss or print characteristics. There is little preference for inks that do not tend to fade.
The range of ink stringing is very limited. This is because serial ink implements many essential tasks. One of the points is that the metering elements, such as ink spoons, make the different ink zones horizontally uniform (30 mm wide on manroland sheet-fed offset printing presses). However, the main task of ink stringing is to eliminate the fluctuation of ink supply on the printing roller produced by the image, that is, to generate ghost images. This is the most important task, requiring a certain length of ink stroke, so that there is only a small change here.
The greatest possibility of effective change is provided by the initial angle of ink jetting, which is the best method to eliminate ink fading that has been adopted in the past, and it has the advantage that there is no worthy “side effect†of the adjustment here. (To be continued)
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