1. Check the flatness of its surface. The method of inspection is to fill the plate, but the printing pressure should be lower than the normal pressure. Only in this way can the surface unevenness be exposed. If the pressure is too high and the ground is thick, it is difficult to see the difference.
If the unevenness of its surface is unacceptable (specific indicators can be determined by experience), the uniformity of the surface of the rubber cloth and lining, as well as the presence of foreign objects on the surface of the drum, can be checked. After removing foreign objects, if unevenness still exists, a "map" can be used. Firstly, draw out each low (or dotted) area, and then apply a sticker to that area on the back of the rubber cloth (the thickness of the sticker depends on the situation).
3. If the surface of the rubber cloth is scratched during use, the solution is the same as 2. But if the rubber blanket is cut, the image it forms is blurred or blank in the middle, transitioning continuously to areas that have not been crushed. This is the most obvious indicator to determine if the rubber blanket has been cut.
4. The surface of the rubber cloth should be acid and oil resistant to prevent damage to its surface layer. Frequent contact with oil can cause aging of the rubber blanket, ultimately leading to relaxation of its internal structure. Rubber blanket often comes into contact with acidic substances, which can cause surface corrosion. It is advisable to clean with fast volatile detergents, such as gasoline, instead of slow volatile substances such as kerosene.
5. Creep and stress relaxation of rubber blanket. After being subjected to force for a long time, there are two manifestations of rubber cloth: a If the length remains unchanged, the stress gradually decreases, which is called stress relaxation; If the stress remains constant, the length will gradually increase, known as creep. After being installed on the drum, the length of the rubber cloth remains unchanged, which will cause stress relaxation. Therefore, after using it for a period of time, the rubber cloth needs to be re tightened. If not used for a long time, the rubber cloth should be loosened to avoid stress relaxation.
6. The surface of the rubber cloth should be kept clean. The effective area of printing needs to be kept clean regularly.
If not cleaned, it will affect the printing pressure. When using rubber blanket, the usual paper used is around 0.05mm, and there is a significant difference in the reproduction of imprints between padding and non padding. From this, it can be seen that this 0.05mm thick paper has a significant effect. In fact, padding 0.05mm thick paper increases the printing pressure by 0.05mm (usually between 0.05-0.5mm). If there is ink or other impurities fixed on the surface of the rubber cloth, the printing pressure will change, thereby affecting the quality of the printed product. Non printing areas should also be kept clean, because when the rubber cloth in the printing area is worn out, sometimes the rubber in the latter half needs to be borrowed (usually the printing surface does not exceed the entire rubber cloth). If this part is not kept clean, as the sludge and other impurities continue to condense and the printing pressure increases, it will damage the surface of the rubber cloth and make it unable to be used normally. The increase in printing pressure will also bring other problems, which will be discussed in the future. One thing to pay attention to when keeping the surface of the rubber cloth clean is the junction of the effective printing area, which contains the most ink and other impurities. Due to the increase in pressure, the fatigue of the rubber blanket accelerates, and it has been found in practice that cracks are most likely to occur in this area of the rubber blanket. Therefore, it is necessary to prevent impurities from accumulating here.
