Nowadays, corrugated printing has evolved from traditional printing processes such as past rubber printing plates and rubber roller transfer inks to high-grade printing using new technologies such as photosensitive resin thin plates and quantitative transfer of ceramic anilox rollers. The printing effect is also from the past. Single pattern and simple text printing develop high-quality thin lines and gradation printing. In addition to attracting more and more attention from users, the novelty design and exquisitely-printed outer packaging can better reflect the quality and grade of the products. Therefore, the manufacturer has higher and higher requirements for the printing quality of product packaging.
In the corrugated printing process, different thicknesses of the printing plate, properties of the printing substrate, the mechanical precision of the printing plate roller, the embossing roller and the bearing all influence the change of printing quality. How can we minimize the impact of these factors and bring the quality of corrugated printing to a new level? This is an important issue that we face. In recent years, the corrugated printing industry all over the world is seeking a way to fundamentally improve the quality of corrugated printing. The R/b ak liner technology was created under such a background. When liners are used, the plates are required to be more accurate. Thin, this R/b ak pad technology is also called thin printing technology.
At present, the domestic corrugated printing uses 7 mm thick printing plates, which are not only easy to change, but also produce dot gains. The plate making cost is also high, which can no longer meet users' requirements for improvement of printing quality. The use of thin plates (photosensitive resin plates with a thickness of 3.94 mm or less, commonly known as thin plates) combined with R/bak air-cushion lining plate technology can not only greatly improve the printing quality of corrugated sheets, but also reduce plate-making costs. To increase the speed of printing presses, this thin-sheet process and R/bak air-cushion lining technology are gradually replacing the traditional thick-type printing plates.
Although the photosensitive resin printing plate and the rubber printing plate have plasticity and have the effect of printing thick corrugated substrate with less plasticity, the printing pressure is too large to cause the printing plate to deform, increase the printing plate fatigue, and make the plate life longer. cut back. In addition, the contact pressure between the anilox roller and the plate, and the pressure control between the plate and the substrate are also particularly important. In order for the ink to be transferred evenly to the plate, the pressure between the plate and the corrugated board, the anilox roll and the plate should be as light as possible. R/b ak air-cushion lining material compared with the resin plate or rubber plate, the flexibility is higher than the latter 2 to 10 times. R/b ak air-cushion lining plate technology can absorb the pressure generated between the printing substrate, printing plate and plate roller, effectively prevent the plate from being deformed and the cardboard is damaged, so that the ink transfer is more uniform and the embossing dot surface is suitable for printing Greater sex and more distinct print patterns.
Below, from the characteristics of corrugated board to analyze the R / b ak air cushion lining for the improvement of corrugated printing quality significance.
Corrugated board properties To achieve successful thin printing on corrugated substrates, it is necessary to understand the mechanical properties of the corrugated substrate, including thickness deviation, crush strength, and flexibility.
After careful observation of the corrugated substrate, you will find that its thickness is not uniform, and its size change is called deviation. For a typical corrugated board, the thickness is mainly determined by the height of the corrugation. Because the printing nip is closed, the plate will first touch the corrugated top, and then it will touch the entire surface to be printed. For direct flexographic printing on corrugated substrates, a printing impression of greater than 0.005 inches is usually required to compensate for this deviation. At the same time, corrugated substrates generally require lower printing pressures, especially when performing thin line and gradation printing. This limits the allowable printing pressure.
Dot enlargement If the print pressure is not greater than the thickness deviation of the substrate, a common wavy line or washboard pattern will appear. Of course, the amount of impressions cannot be increased without limit. To control fine lines and gradations, you need to maintain moderate printing pressure. Excessive pressure on any substrate can cause dots to grow, that is, mushroom-like (Figure 1).
The paperboard breakage strength can also cause damage to the paperboard if the printing pressure is too high (Fig. 2). If the amount of compression is maintained at a level below the breakage strength of the paperboard, the springback will be resumed when the substrate leaves the print nip; if its corrugated wall is press-folded, ie beyond the limit compression of the paperboard, the paperboard Will not return to its original thickness.
Compression absorption of thin hard corrugated board is lower than that of the original printing plate, but most corrugated board plasticity is higher than many plates. As a typical example, the plasticity of paperboard and plate is 0.001 and 0.002 inch/PSI, respectively. When the compression amount of the embossing is 0.01 inch, the printing plate and paper plate are compressed to 0.0033 and 0 respectively. .0067 inches. For thicker printing, this impression may be excessive, but an air-cushioned backing plate with a plasticity of 0.007 inch/PSI is used. At the same 0.01 inch compression, the compression of the paperboard and the printing plate are respectively At 0.001 and 0.002 inches, the lining plate has a compression of 0.007 inches. It can be seen that the use of R/bak lithography technology reduces the amount of compression of the printing plate and the paperboard, so that the lithographic plate absorbs a greater amount of compression.
In thin printing, since the susceptor absorbs the deformation caused when the compression amount is printed, a compression amount greater than 0.010 inch can be used in thin printing without damaging the cardboard. For old presses where the eccentricity of the roller and bearing wear exceeds 0.002 inch (0.05 mm), the R/bak reticle can be used to make up for the deficiencies.
Application examples The printing plate roller and the embossing roller gap of the general ink printing machine is between 5 and 7mm. How to use the thin plate printing technology to choose the lining plate?
If the gap between the plate roller and the embossing roller is 7mm, a combination of a 3.94mm plate and a 3.05mm reticle may be used.
If the gap between the plate roller and the embossing roller is 5mm, it is recommended to use 2.84mm printing plate and 2.03mmR/b ak lining plate. If you have used 3.94mm plate, and these plates can still be used, you can choose 1 .02mm lining plate. Of course, the combination of a 2.84mm plate and a 2.03mm reticle is better.
R/b ak air-cushion lining plate has two kinds of elasticity and a variety of thickness specifications, which can be combined with standard thin-type printing plates. It can be applied to any gap machine to meet different printing requirements.
The quality of the lining plate discriminating lining plate directly affects the printing quality. How to select and identify the following three items:
a) Resilience; b) Leveling accuracy; c) Service life.
Resilient energy identification: The method is extremely simple, as long as the use of ballpoint pen or fingernail pressed hard on the material to be tested for a while, if found on the material indentation, the material rebound is poor, not as a printing pad.
Leveling Accuracy Test: The available thickness gauge can also be used to measure the thickness of the vernier card or micrometer to see if the thickness is consistent.
Lifetime identification: Determined by whether the liner has a PE protective film and resilience. The backing plate with a protective film has a large strength, is easy to mount, and is not easy to damage. The resilient backing is durable and does not deform for many years.
The main advantages of the lining plate 1 Reduce the pressure on the printing surface and effectively control the dot expansion.
2 to avoid cardboard deformation, reduce the defective rate.
3 Reduce the cost of plate making and extend the life of the plate.
4 Increase printing speed and increase production efficiency.
5 It has a unique compensation effect for the oversized plate roller.
6 Good printability for low quality corrugated board and avoid damage to corrugated board.
7 Improve the print quality of ordinary or old equipment.
R/b ak air-cushion lining technology is a mature technology widely used in corrugated printing. It is regarded as the most direct and effective solution to improve printing quality. Simply speaking, the use of R/b ak air-cushion lining plate can play a role in buffering the pressure between the printing substrate, the printing plate, and the printing plate roller to avoid the damage of the paper plate and the variation of the printing plate. The application of R/b ak air-cushion lining technology has become an important way for domestic and foreign corrugated printing plants and machine factories to improve product quality. (Wang Yan)
In the corrugated printing process, different thicknesses of the printing plate, properties of the printing substrate, the mechanical precision of the printing plate roller, the embossing roller and the bearing all influence the change of printing quality. How can we minimize the impact of these factors and bring the quality of corrugated printing to a new level? This is an important issue that we face. In recent years, the corrugated printing industry all over the world is seeking a way to fundamentally improve the quality of corrugated printing. The R/b ak liner technology was created under such a background. When liners are used, the plates are required to be more accurate. Thin, this R/b ak pad technology is also called thin printing technology.
At present, the domestic corrugated printing uses 7 mm thick printing plates, which are not only easy to change, but also produce dot gains. The plate making cost is also high, which can no longer meet users' requirements for improvement of printing quality. The use of thin plates (photosensitive resin plates with a thickness of 3.94 mm or less, commonly known as thin plates) combined with R/bak air-cushion lining plate technology can not only greatly improve the printing quality of corrugated sheets, but also reduce plate-making costs. To increase the speed of printing presses, this thin-sheet process and R/bak air-cushion lining technology are gradually replacing the traditional thick-type printing plates.
Although the photosensitive resin printing plate and the rubber printing plate have plasticity and have the effect of printing thick corrugated substrate with less plasticity, the printing pressure is too large to cause the printing plate to deform, increase the printing plate fatigue, and make the plate life longer. cut back. In addition, the contact pressure between the anilox roller and the plate, and the pressure control between the plate and the substrate are also particularly important. In order for the ink to be transferred evenly to the plate, the pressure between the plate and the corrugated board, the anilox roll and the plate should be as light as possible. R/b ak air-cushion lining material compared with the resin plate or rubber plate, the flexibility is higher than the latter 2 to 10 times. R/b ak air-cushion lining plate technology can absorb the pressure generated between the printing substrate, printing plate and plate roller, effectively prevent the plate from being deformed and the cardboard is damaged, so that the ink transfer is more uniform and the embossing dot surface is suitable for printing Greater sex and more distinct print patterns.
Below, from the characteristics of corrugated board to analyze the R / b ak air cushion lining for the improvement of corrugated printing quality significance.
Corrugated board properties To achieve successful thin printing on corrugated substrates, it is necessary to understand the mechanical properties of the corrugated substrate, including thickness deviation, crush strength, and flexibility.
After careful observation of the corrugated substrate, you will find that its thickness is not uniform, and its size change is called deviation. For a typical corrugated board, the thickness is mainly determined by the height of the corrugation. Because the printing nip is closed, the plate will first touch the corrugated top, and then it will touch the entire surface to be printed. For direct flexographic printing on corrugated substrates, a printing impression of greater than 0.005 inches is usually required to compensate for this deviation. At the same time, corrugated substrates generally require lower printing pressures, especially when performing thin line and gradation printing. This limits the allowable printing pressure.
Dot enlargement If the print pressure is not greater than the thickness deviation of the substrate, a common wavy line or washboard pattern will appear. Of course, the amount of impressions cannot be increased without limit. To control fine lines and gradations, you need to maintain moderate printing pressure. Excessive pressure on any substrate can cause dots to grow, that is, mushroom-like (Figure 1).
The paperboard breakage strength can also cause damage to the paperboard if the printing pressure is too high (Fig. 2). If the amount of compression is maintained at a level below the breakage strength of the paperboard, the springback will be resumed when the substrate leaves the print nip; if its corrugated wall is press-folded, ie beyond the limit compression of the paperboard, the paperboard Will not return to its original thickness.
Compression absorption of thin hard corrugated board is lower than that of the original printing plate, but most corrugated board plasticity is higher than many plates. As a typical example, the plasticity of paperboard and plate is 0.001 and 0.002 inch/PSI, respectively. When the compression amount of the embossing is 0.01 inch, the printing plate and paper plate are compressed to 0.0033 and 0 respectively. .0067 inches. For thicker printing, this impression may be excessive, but an air-cushioned backing plate with a plasticity of 0.007 inch/PSI is used. At the same 0.01 inch compression, the compression of the paperboard and the printing plate are respectively At 0.001 and 0.002 inches, the lining plate has a compression of 0.007 inches. It can be seen that the use of R/bak lithography technology reduces the amount of compression of the printing plate and the paperboard, so that the lithographic plate absorbs a greater amount of compression.
In thin printing, since the susceptor absorbs the deformation caused when the compression amount is printed, a compression amount greater than 0.010 inch can be used in thin printing without damaging the cardboard. For old presses where the eccentricity of the roller and bearing wear exceeds 0.002 inch (0.05 mm), the R/bak reticle can be used to make up for the deficiencies.
Application examples The printing plate roller and the embossing roller gap of the general ink printing machine is between 5 and 7mm. How to use the thin plate printing technology to choose the lining plate?
If the gap between the plate roller and the embossing roller is 7mm, a combination of a 3.94mm plate and a 3.05mm reticle may be used.
If the gap between the plate roller and the embossing roller is 5mm, it is recommended to use 2.84mm printing plate and 2.03mmR/b ak lining plate. If you have used 3.94mm plate, and these plates can still be used, you can choose 1 .02mm lining plate. Of course, the combination of a 2.84mm plate and a 2.03mm reticle is better.
R/b ak air-cushion lining plate has two kinds of elasticity and a variety of thickness specifications, which can be combined with standard thin-type printing plates. It can be applied to any gap machine to meet different printing requirements.
The quality of the lining plate discriminating lining plate directly affects the printing quality. How to select and identify the following three items:
a) Resilience; b) Leveling accuracy; c) Service life.
Resilient energy identification: The method is extremely simple, as long as the use of ballpoint pen or fingernail pressed hard on the material to be tested for a while, if found on the material indentation, the material rebound is poor, not as a printing pad.
Leveling Accuracy Test: The available thickness gauge can also be used to measure the thickness of the vernier card or micrometer to see if the thickness is consistent.
Lifetime identification: Determined by whether the liner has a PE protective film and resilience. The backing plate with a protective film has a large strength, is easy to mount, and is not easy to damage. The resilient backing is durable and does not deform for many years.
The main advantages of the lining plate 1 Reduce the pressure on the printing surface and effectively control the dot expansion.
2 to avoid cardboard deformation, reduce the defective rate.
3 Reduce the cost of plate making and extend the life of the plate.
4 Increase printing speed and increase production efficiency.
5 It has a unique compensation effect for the oversized plate roller.
6 Good printability for low quality corrugated board and avoid damage to corrugated board.
7 Improve the print quality of ordinary or old equipment.
R/b ak air-cushion lining technology is a mature technology widely used in corrugated printing. It is regarded as the most direct and effective solution to improve printing quality. Simply speaking, the use of R/b ak air-cushion lining plate can play a role in buffering the pressure between the printing substrate, the printing plate, and the printing plate roller to avoid the damage of the paper plate and the variation of the printing plate. The application of R/b ak air-cushion lining technology has become an important way for domestic and foreign corrugated printing plants and machine factories to improve product quality. (Wang Yan)
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