The structure of the offset blanket is designed based on the total distance between the cylinder spacing of the printing press and the thickness of the outer liner of the blanket cylinder, taking into account the printing technology requirements (such as ink, solvent and printing pressure).
1, the total thickness: the thickness of the domestic blanket with the same foreign products, the total thickness of l.80 ~ 1.90 mm. There are also a small number of blankets with a total thickness of 160-1.70 mm, which consists of three base fabrics.
2, the thickness of the surface glue: the thickness of the surface glue should be appropriate, generally 0.6 ~ 0.7 mm, if the thickness is too thin, the elasticity is low, the hardness is too high, will wear the printing plate, reduce the printing plate resistance to printing force, will also make the network point not Full, the screen from the ink (that is, the screen from the article), different shades of black; surface glue is too thick will make the print network dot deformation (such as dot gain, elongation, etc.) lead to imprint movement, overprinting is not allowed, the picture is blurred.
3, the thickness of the cloth glue; cloth glue mainly from the bonding bottom cloth, increase the role of flexibility. Its thickness is limited by the thickness of the surface glue and the total thickness. It is generally controlled at 1.2 to 1.3 mm (including four base fabrics).
The thickness of the adhesive layer between the four layers of backing cloth is also different. The thickness and performance design of the adhesive layer between 1 and 2 layers of backing fabric mainly consider the compressibility and softness of the adhesive layer close to the printing surface. The thickness and performance of the adhesive layer between the 3 to 4 layers of the backing cloth only serve to bond the backing cloth.
4. The number and thickness of the bottom cloth: The radial force of the blanket during printing is very large, which is nearly 100O kg. Therefore, the blanket must be selected as the skeleton material of high-strength cotton.
5, the structure of air-cushion blanket: Air-cushion blanket appearance and ordinary blanket no obvious difference, its thickness is roughly divided between several 1.65 ~ 1.9 mm specifications, air-cushion blanket and ordinary blanket The main difference is that it not only has different fabric layers and rubber layers, but also has a gas-filled layer sandwiched between them to form an elastic layer. The gas-filled layer is mainly divided into microbubbles and gas channels.