The role of the impression cylinder is to apply pressure on the substrate material so that the substrate material and the plate cylinder are in close contact, so that the ink in the cell of the plate cylinder can be transferred to the substrate material. image.
The design of the impression cylinder The core of the impression cylinder is generally composed of steel material and is covered with a rubber layer. The diameter of the impression cylinder is not the same as the diameter of the plate cylinder. Both ends of the impression cylinder are supported by bearings, mainly to ensure that the impression cylinder can maintain its balance during the printing process and avoid large vibrations.
Although the manufacturer of the impression cylinder can be processed according to the parameters provided by the printer manufacturer, the following points are determined by the printer:
1. The coating material should be determined according to the condition of the printing press. The most commonly used materials are: natural rubber, neoprene, nitrile rubber, and polyurethane.
2. The shape of the outer rubber layer at the joints at both ends of the impression cylinder.
Physical properties of the rubber layer The physical properties of the outer rubber layer mainly include: hardness (Shore hardness), heat resistance, elasticity, heat accumulation properties, abrasion resistance, chemical resistance, and the like.
The hardness of the rubber material of the impression roller The degree of hardness and hardness of the rubber material can be expressed in terms of Shore hardness. The hardness of the rubber material can be measured using the hardness tester.
In order to be able to precisely control the amount of ink transferred to the substrate material, it must be ensured that the substrate material is in close contact with the ink in the cells. So, in the end should choose how much hardness of rubber material is more appropriate? This depends to a large extent on the type of substrate material.
The rougher the substrate material, the greater the elasticity, the greater the hardness of the rubber layer of the impression cylinder. For example, an impression cylinder with a rubber layer hardness of 90 Shore A or more is suitable for printing recycled cardboard. Under the same conditions, when printing with a larger impression cylinder, a larger printing pressure can be applied without causing deformation.
If the surface of the substrate material is very smooth and its weight is lighter, a softer rubber material should be used, and the required pressure is generally smaller.
If the substrate material is relatively hard and relatively smooth, you should use a relatively soft rubber material, but it should not be too soft, otherwise it will produce deformation and wrinkles, generally 80 Shore hardness around the impression cylinder.
If the substrate material is soft and relatively smooth, an embossing cylinder with a 70 Shore hardness is appropriate.
The size of the impression cylinder must also take into account the size of the impression cylinder when selecting the hardness of the rubber material, which is also a very important factor. We all know that the reason why the ink in the cell can be adsorbed is mainly due to capillary action. This is why it is necessary to form a vacuum at the imprinted contact area. This is very important. The contact area between the impression cylinder and plate cylinder is called "nip". In general, the rougher the surface of the sheet material, the wider the contact area, the larger the required impression cylinder diameter, and vice versa the smaller the diameter of the mine impression cylinder. The reason is that rough surface of the substrate is uneven, there are many "pits" can not touch the ink in the roller compartment, so in order to be able to form the necessary vacuum, you need to increase the contact area.
In order to prevent the impression cylinder from bending during the application of pressure, a steel press roll has been added to many presses, especially those with very wide webs. When a high pressure is applied, if the central portion of the printed matter is white and the image is not printed, it can be concluded that the impression cylinder has undergone a bending deformation. (Shu Wen) ("China Packaging News and Printing Weekly")
The design of the impression cylinder The core of the impression cylinder is generally composed of steel material and is covered with a rubber layer. The diameter of the impression cylinder is not the same as the diameter of the plate cylinder. Both ends of the impression cylinder are supported by bearings, mainly to ensure that the impression cylinder can maintain its balance during the printing process and avoid large vibrations.
Although the manufacturer of the impression cylinder can be processed according to the parameters provided by the printer manufacturer, the following points are determined by the printer:
1. The coating material should be determined according to the condition of the printing press. The most commonly used materials are: natural rubber, neoprene, nitrile rubber, and polyurethane.
2. The shape of the outer rubber layer at the joints at both ends of the impression cylinder.
Physical properties of the rubber layer The physical properties of the outer rubber layer mainly include: hardness (Shore hardness), heat resistance, elasticity, heat accumulation properties, abrasion resistance, chemical resistance, and the like.
The hardness of the rubber material of the impression roller The degree of hardness and hardness of the rubber material can be expressed in terms of Shore hardness. The hardness of the rubber material can be measured using the hardness tester.
In order to be able to precisely control the amount of ink transferred to the substrate material, it must be ensured that the substrate material is in close contact with the ink in the cells. So, in the end should choose how much hardness of rubber material is more appropriate? This depends to a large extent on the type of substrate material.
The rougher the substrate material, the greater the elasticity, the greater the hardness of the rubber layer of the impression cylinder. For example, an impression cylinder with a rubber layer hardness of 90 Shore A or more is suitable for printing recycled cardboard. Under the same conditions, when printing with a larger impression cylinder, a larger printing pressure can be applied without causing deformation.
If the surface of the substrate material is very smooth and its weight is lighter, a softer rubber material should be used, and the required pressure is generally smaller.
If the substrate material is relatively hard and relatively smooth, you should use a relatively soft rubber material, but it should not be too soft, otherwise it will produce deformation and wrinkles, generally 80 Shore hardness around the impression cylinder.
If the substrate material is soft and relatively smooth, an embossing cylinder with a 70 Shore hardness is appropriate.
The size of the impression cylinder must also take into account the size of the impression cylinder when selecting the hardness of the rubber material, which is also a very important factor. We all know that the reason why the ink in the cell can be adsorbed is mainly due to capillary action. This is why it is necessary to form a vacuum at the imprinted contact area. This is very important. The contact area between the impression cylinder and plate cylinder is called "nip". In general, the rougher the surface of the sheet material, the wider the contact area, the larger the required impression cylinder diameter, and vice versa the smaller the diameter of the mine impression cylinder. The reason is that rough surface of the substrate is uneven, there are many "pits" can not touch the ink in the roller compartment, so in order to be able to form the necessary vacuum, you need to increase the contact area.
In order to prevent the impression cylinder from bending during the application of pressure, a steel press roll has been added to many presses, especially those with very wide webs. When a high pressure is applied, if the central portion of the printed matter is white and the image is not printed, it can be concluded that the impression cylinder has undergone a bending deformation. (Shu Wen) ("China Packaging News and Printing Weekly")
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