The rubber roller is an important part of the offset press. Its quality directly affects the quality of the printed matter. However, due to blind spots in the understanding, people often lack understanding of the properties and characteristics of the rubber roller, and many links such as design, manufacture, use, etc. cannot be achieved. A reasonable, comprehensive, and standardized index is required for the rubber roller, and there is no uniform regulation for inspection and testing methods. Many printers in the design of rubber roller quality requirements only put forward the physical requirements of the hardness index, proposed geometric accuracy of the size of the allowable range of changes, the surface quality requirements of the roughness, a very small number of printing speeds of 10,000 or more per hour The product proposed the dynamic and static balance requirements for mechanical properties, but did not involve other physical properties such as elasticity indexes, chemical properties such as corrosion resistance and aging resistance.
On the medium and low speed offset presses, due to the low printing speed, the rubber roller has low compression frequency when transferring ink, and the compression springback time is allowed to be relatively longer. Therefore, there is no special need for the rebound elasticity of the rubber roller. Only rubber is evaluated in the actual engineering drawings. Hardness, hardness indicators to determine the quality and aging of the roller. In fact, the hardness index and elasticity index of the rubber roller are two different physical quantities. Although they have certain connections, they also have obvious differences. Strictly speaking, they cannot replace each other. The definition of elasticity is the ability of an object to deform by force, remove external forces, and restore its original shape. The better the elasticity, the stronger the ability to restore the original shape and the less time it takes to restore the original shape. The hardness is the ability of the object to resist the deformation of the external force, the higher the hardness, the more difficult it is to deform the object after the force. When the two materials have the same hardness and different elasticities, they have the same degree of deformation under the same force, but after the external force is removed, the two have different abilities to recover the original shape. Materials with good elasticity can quickly return to their original state, and those with poor elasticity can only slowly return to the original state.
Obviously, they have different effects on printing and ink transfer. When the rubber roller transfers ink, there is a certain pressure between the rubber roller and the rubber roller, they are compressed, the roller rotates at a slight angle from the contact line, the pressure on the roller is removed, the compressed roller quickly returns to the original shape, and the original Constant pressure delivers the ink to the next level. The original pressure is achieved by the rubber roller restoring the original shape of the size. If the elasticity of the rubber roller is poor and cannot be quickly restored to its original size and shape, the pressure balance between the ink transfer roller is destroyed. In the process of ink transfer, the rubber rollers with poor elasticity often cannot meet the printing requirements of high-profile and small dots, and can not express the heavy sense of low-key fullness of ink. Dots are made imaginary and whitish, and the screen is dull and dull.
The higher the density of the printed wire and the faster the printing speed, the higher the elasticity of the rubber roller must be. Only the elastic roller can leave round and plump ink on the roller or printing plate. Some printing factory masters often find that the printing pressure is low when they see outlets failing. Therefore, blindly increasing the printing pressure results in little success; some printing factory masters simply increase the pressure of the rubber rollers when they see the outlets, and eventually lead to glue. Roller compression increases, the roller is prone to heat after a period of operation. The rubber roller is working under high temperature for a long time, so that the rubber roller is easy to be aged and the service life is shortened. High-speed offset presses have faster rotation speeds, and they compress more times per unit time than low-speed machines. At high speeds, the amount of compression often takes a large value to ensure the effect of ink transfer. This requires more flexible rubber. Rollers also explain why high-speed machines are more prone to false printing because of the poor quality of the rollers. In the same way, if the water roller has poor elasticity and the water is uneven, it is also difficult to achieve ink-water balance. On high-speed high-grade offset presses, air-cushion blankets are used to achieve excellent printing and transfer of ink, which is to make full use of the rubber blanket's good resilience performance.
As mentioned above, because our country knows little about the quality of the rubber roller, including the printing machine's national standards, there is no guidance, and the chemical industry standards, although there are physical performance requirements, but the lack of operability, the national standard GB / T1681 can not be sampled on the roller, so in fact every printer manufacturer's supplier of rubber roller does not really evaluate the elasticity index of the roller. At present, the performance of domestic offset printing presses is generally improving. The printing speeds of well-known domestic offset presses such as Changsheng Group, Beiren Group, and Shanghai Guanghua have reached 15,000 impressions per hour, and the quality of printed matter is constantly approaching European standards. The quality index requirements, testing methods, and confirmation of testing instruments are naturally mentioned in the daily routine. Jiangsu Changsheng Group cooperated with the Beijing Institute of Graphic Communication and well-known rubber roller suppliers in China to test, compare, classify, and test the rubber rollers in different functional areas of machines at home and abroad, and formulated the elasticity indexes of various types of rubber rollers in each functional area. And strictly enforced, so that the quality of printer products has been continuously improved.
Improve and improve the performance of the rubber roller, not only the printing machine factory, use and maintenance are equally important. Many printing companies have been using medium- and low-speed machines for a long period of time, and have been printing low-grade jobs. They have not done enough articles on the maintenance and repair of rubber rollers. Especially in the car washing process, they do not clean the rubber roller ink in time. Second, the cleaning roller usually uses corrosion. Strong gasoline, which will lead to aging rubber rubber layer deterioration, loss of elasticity. Because the ink has corrosion and aging effects on the rubber roller, the rubber roller will not be cleaned for a long time, and the surface will be hard to be hardened, cracked, and lose its elasticity, which is also called vitrification, which seriously affects the ink transfer performance of the rubber roller. Cleaning the rubber roller with gasoline can cause corrosion and corrosion of the roller body rubber. Therefore, for high-grade offset printing machines and offset printing machines that need to print high-end live printing, authentic car washing water must be purchased so that the elasticity of the rubber roller and excellent ink transfer performance can be maintained for a long time.
On the medium and low speed offset presses, due to the low printing speed, the rubber roller has low compression frequency when transferring ink, and the compression springback time is allowed to be relatively longer. Therefore, there is no special need for the rebound elasticity of the rubber roller. Only rubber is evaluated in the actual engineering drawings. Hardness, hardness indicators to determine the quality and aging of the roller. In fact, the hardness index and elasticity index of the rubber roller are two different physical quantities. Although they have certain connections, they also have obvious differences. Strictly speaking, they cannot replace each other. The definition of elasticity is the ability of an object to deform by force, remove external forces, and restore its original shape. The better the elasticity, the stronger the ability to restore the original shape and the less time it takes to restore the original shape. The hardness is the ability of the object to resist the deformation of the external force, the higher the hardness, the more difficult it is to deform the object after the force. When the two materials have the same hardness and different elasticities, they have the same degree of deformation under the same force, but after the external force is removed, the two have different abilities to recover the original shape. Materials with good elasticity can quickly return to their original state, and those with poor elasticity can only slowly return to the original state.
Obviously, they have different effects on printing and ink transfer. When the rubber roller transfers ink, there is a certain pressure between the rubber roller and the rubber roller, they are compressed, the roller rotates at a slight angle from the contact line, the pressure on the roller is removed, the compressed roller quickly returns to the original shape, and the original Constant pressure delivers the ink to the next level. The original pressure is achieved by the rubber roller restoring the original shape of the size. If the elasticity of the rubber roller is poor and cannot be quickly restored to its original size and shape, the pressure balance between the ink transfer roller is destroyed. In the process of ink transfer, the rubber rollers with poor elasticity often cannot meet the printing requirements of high-profile and small dots, and can not express the heavy sense of low-key fullness of ink. Dots are made imaginary and whitish, and the screen is dull and dull.
The higher the density of the printed wire and the faster the printing speed, the higher the elasticity of the rubber roller must be. Only the elastic roller can leave round and plump ink on the roller or printing plate. Some printing factory masters often find that the printing pressure is low when they see outlets failing. Therefore, blindly increasing the printing pressure results in little success; some printing factory masters simply increase the pressure of the rubber rollers when they see the outlets, and eventually lead to glue. Roller compression increases, the roller is prone to heat after a period of operation. The rubber roller is working under high temperature for a long time, so that the rubber roller is easy to be aged and the service life is shortened. High-speed offset presses have faster rotation speeds, and they compress more times per unit time than low-speed machines. At high speeds, the amount of compression often takes a large value to ensure the effect of ink transfer. This requires more flexible rubber. Rollers also explain why high-speed machines are more prone to false printing because of the poor quality of the rollers. In the same way, if the water roller has poor elasticity and the water is uneven, it is also difficult to achieve ink-water balance. On high-speed high-grade offset presses, air-cushion blankets are used to achieve excellent printing and transfer of ink, which is to make full use of the rubber blanket's good resilience performance.
As mentioned above, because our country knows little about the quality of the rubber roller, including the printing machine's national standards, there is no guidance, and the chemical industry standards, although there are physical performance requirements, but the lack of operability, the national standard GB / T1681 can not be sampled on the roller, so in fact every printer manufacturer's supplier of rubber roller does not really evaluate the elasticity index of the roller. At present, the performance of domestic offset printing presses is generally improving. The printing speeds of well-known domestic offset presses such as Changsheng Group, Beiren Group, and Shanghai Guanghua have reached 15,000 impressions per hour, and the quality of printed matter is constantly approaching European standards. The quality index requirements, testing methods, and confirmation of testing instruments are naturally mentioned in the daily routine. Jiangsu Changsheng Group cooperated with the Beijing Institute of Graphic Communication and well-known rubber roller suppliers in China to test, compare, classify, and test the rubber rollers in different functional areas of machines at home and abroad, and formulated the elasticity indexes of various types of rubber rollers in each functional area. And strictly enforced, so that the quality of printer products has been continuously improved.
Improve and improve the performance of the rubber roller, not only the printing machine factory, use and maintenance are equally important. Many printing companies have been using medium- and low-speed machines for a long period of time, and have been printing low-grade jobs. They have not done enough articles on the maintenance and repair of rubber rollers. Especially in the car washing process, they do not clean the rubber roller ink in time. Second, the cleaning roller usually uses corrosion. Strong gasoline, which will lead to aging rubber rubber layer deterioration, loss of elasticity. Because the ink has corrosion and aging effects on the rubber roller, the rubber roller will not be cleaned for a long time, and the surface will be hard to be hardened, cracked, and lose its elasticity, which is also called vitrification, which seriously affects the ink transfer performance of the rubber roller. Cleaning the rubber roller with gasoline can cause corrosion and corrosion of the roller body rubber. Therefore, for high-grade offset printing machines and offset printing machines that need to print high-end live printing, authentic car washing water must be purchased so that the elasticity of the rubber roller and excellent ink transfer performance can be maintained for a long time.
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