How to properly tighten the blanket
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The blanket must be taut on the blanket cylinder under the appropriate tension. If the blanket is too loose, when the blanket is imprinted, it will be displaced under the action of the squeezing force and cannot be reset in time, which may cause a ghosting failure. If the blanket is stretched too tight, there are many drawbacks:
1. The rubber layer is thinned and the elasticity is lowered. If the printing pressure is calculated by the thickness measured by the micrometer in the field of the blanket, the printing pressure may be insufficient due to excessive thinning of the rubber layer. The thinning of the strand reduces the elasticity of the blanket, and even if the amount of compression is increased by decreasing the center distance, the phenomenon of poor ink transfer may occur. If it is an air-cushion blanket, too tightly stretched may also invalidate the micro-bubble sponge layer and lose the good performance of the air-cushion blanket.
2. Lead to uneven printing pressure. Since the tensile force of the blanket at different positions in the circumferential direction is uneven under the action of the tension, the thickness reduction is uneven in the circumferential direction, resulting in uneven printing pressure. The tighter the tension, the more serious this unevenness. The unevenness of the pressure causes the unevenness of the ink transfer, so that the solid or flat background color which should be uniform is made uneven, and the hue of the color image is shifted.
3. Affects the synchronous rolling state. The fine fruit has a good synchronous rolling state between the three rollers under the normal blanket tension and the blanket thickness of the blanket cylinder, so in the case of excessive tension, the blanket cylinder is synchronized with the plate cylinder and the impression cylinder. The rolling ratio will rise, destroying the synchronous rolling state, and sliding between the three rollers affects the correct transfer of the dots, destroying the restoration of the level and color.
4. Accelerated creep and aging of the blanket. The tighter the tension, the more likely it is to cause a conformational change in the rubber molecules, the molecular chain is stiff, the elasticity of the rubber is deteriorated, affecting the quality of the product and shortening the service life of the blanket.