The optimal printing pressure is also called the ideal printing pressure. That is, under the condition that the printed surface is compressively deformed, the minimum pressure used for making the print sufficiently strong and uniform. To achieve the best printing pressure must also be achieved: complete imprinting, smooth, clean, distinct, colorful, minimal deformation. This article analyzes the factors related to achieving the best printing pressure in order to discuss with everyone.
First, the conditions for achieving optimal printing pressure
There are many factors involved in achieving optimal printing pressure. In addition, the optimal pressure is not fixed, but should be adjusted according to various objective printing conditions under the premise of favorable print quality. All the following factors must be in the best state of fit.
1. From the aspect of the printing press cylinder, in theory, the cylinder must be parallel to the centerline of the cylinder during imprinting; the pitch circle of the gear is tangential; the actual radius of the cylinder is equal; the linear velocity of the surface of each cylinder is the same.
2. From the paper point of view, different amounts of paper, different between the blanket cylinder and the impression cylinder have different amounts of compression, the amount of compression required for coated paper is small, and the amount of compression required for offset paper is large. Because the surface roughness of offset paper is large, the amount of compression is not increased, some temples may not be printed, and the surface roughness of coated paper is small, the amount of compression is large, the deformation of the imprint is increased quickly, and it is easy to paste. Version.
3. From the perspective of ink-water balance, ink-water balance is the guarantee of printing quality. As the pressure of printing changes, the balance of ink and water also changes. The printing pressure is too large, and the imprinting is easy to spread. This leads to a vicious cycle of “water, ink, and ink†and destroys the ink and water balance.
4. The hydrophilicity of the printing plate, the printing color sequence, the change of the environment temperature and humidity and other factors all must reach the best fitness to achieve the best printing pressure.
5. Due to various factors, the best printing pressure adjustment method is: the gear in the standard mesh state, by changing the thickness of the liner, to achieve the best printability. In addition, when printing thicker paper, the best printing pressure method is: 1 reduce the thickness of the liner under the blanket cylinder. 2 Increase the liner thickness under the plate cylinder. 3 Minor difference can be compensated by changes in center distance.
Second, the common factors that undermine the best printing pressure
Although the best pressure is recognized by everyone, it is not all very important or can be achieved. In addition to not complying with the above-mentioned operation to achieve optimal pressure, in the production, the phenomenon of inappropriate pressure due to ideological and technical problems is often caused, and care should be taken to prevent and correct it. It is particularly prone to excessive pressure (because the pressure is too small to be noticeable). The consequences are very serious. Common factors are as follows:
1. The problem of imprint transfer occurred in production. There was no comprehensive analysis of the causes. Blindly changing the center distance of the rollers or adding spacers not only failed to achieve the best printing effect, but also undermined the normal operation of the rollers and accelerated the gears and bearings. Wear.
2. Inaccurate measurements of blankets, plates, or underlays disrupt the achievement of optimum printing pressure. Some operators do not measure the thickness of the printing plate. When the blanket is installed, the measurement is inaccurate. Especially for new blankets and new linings, it is easy to measure and inaccurate, which inevitably results in improper gaskets and severely destroys the optimal printing pressure.
3. Due to the poor leveling of the blanket and the low surface ink absorption capacity due to various reasons, it was mistaken for the pressure to increase the padding, resulting in excessive pressure.
4. Due to the poor contact between the ink roller and the printing plate, the ink may not be transferred normally, which is often mistaken for the lack of roller pressure to increase the pad, resulting in excessive pressure.
5. Due to various reasons caused by the ink spread, resulting in dark and uneven blotting ink, it is often very easy to be mistaken for pressure, and increase the printing pressure.
First, the conditions for achieving optimal printing pressure
There are many factors involved in achieving optimal printing pressure. In addition, the optimal pressure is not fixed, but should be adjusted according to various objective printing conditions under the premise of favorable print quality. All the following factors must be in the best state of fit.
1. From the aspect of the printing press cylinder, in theory, the cylinder must be parallel to the centerline of the cylinder during imprinting; the pitch circle of the gear is tangential; the actual radius of the cylinder is equal; the linear velocity of the surface of each cylinder is the same.
2. From the paper point of view, different amounts of paper, different between the blanket cylinder and the impression cylinder have different amounts of compression, the amount of compression required for coated paper is small, and the amount of compression required for offset paper is large. Because the surface roughness of offset paper is large, the amount of compression is not increased, some temples may not be printed, and the surface roughness of coated paper is small, the amount of compression is large, the deformation of the imprint is increased quickly, and it is easy to paste. Version.
3. From the perspective of ink-water balance, ink-water balance is the guarantee of printing quality. As the pressure of printing changes, the balance of ink and water also changes. The printing pressure is too large, and the imprinting is easy to spread. This leads to a vicious cycle of “water, ink, and ink†and destroys the ink and water balance.
4. The hydrophilicity of the printing plate, the printing color sequence, the change of the environment temperature and humidity and other factors all must reach the best fitness to achieve the best printing pressure.
5. Due to various factors, the best printing pressure adjustment method is: the gear in the standard mesh state, by changing the thickness of the liner, to achieve the best printability. In addition, when printing thicker paper, the best printing pressure method is: 1 reduce the thickness of the liner under the blanket cylinder. 2 Increase the liner thickness under the plate cylinder. 3 Minor difference can be compensated by changes in center distance.
Second, the common factors that undermine the best printing pressure
Although the best pressure is recognized by everyone, it is not all very important or can be achieved. In addition to not complying with the above-mentioned operation to achieve optimal pressure, in the production, the phenomenon of inappropriate pressure due to ideological and technical problems is often caused, and care should be taken to prevent and correct it. It is particularly prone to excessive pressure (because the pressure is too small to be noticeable). The consequences are very serious. Common factors are as follows:
1. The problem of imprint transfer occurred in production. There was no comprehensive analysis of the causes. Blindly changing the center distance of the rollers or adding spacers not only failed to achieve the best printing effect, but also undermined the normal operation of the rollers and accelerated the gears and bearings. Wear.
2. Inaccurate measurements of blankets, plates, or underlays disrupt the achievement of optimum printing pressure. Some operators do not measure the thickness of the printing plate. When the blanket is installed, the measurement is inaccurate. Especially for new blankets and new linings, it is easy to measure and inaccurate, which inevitably results in improper gaskets and severely destroys the optimal printing pressure.
3. Due to the poor leveling of the blanket and the low surface ink absorption capacity due to various reasons, it was mistaken for the pressure to increase the padding, resulting in excessive pressure.
4. Due to the poor contact between the ink roller and the printing plate, the ink may not be transferred normally, which is often mistaken for the lack of roller pressure to increase the pad, resulting in excessive pressure.
5. Due to various reasons caused by the ink spread, resulting in dark and uneven blotting ink, it is often very easy to be mistaken for pressure, and increase the printing pressure.
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