How to tighten the blanket correctly

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How to tighten the rubber blanket correctly

the rubber blanket must be tightened on the rubber drum under the action of appropriate tightening force. If the blanket is stretched too loosely, the blanket will shift under the action of extrusion pressure and cannot be reset in time, which will lead to ghosting failure. If the blanket is too tight, it will bring many disadvantages:

1. The adhesive layer is thinner and the elasticity is reduced. If the printing pressure is calculated by the thickness measured by the micrometer under the condition that the rubber blanket clamp is made of metal, the printing pressure may be insufficient due to excessive thinning of the adhesive layer. The thinning of the ply reduces the elasticity of the blanket, and poor ink transfer may occur even when the center distance is reduced and the compression is increased. If it is air cushion blanket, too tight may also make the micro foam sponge layer invalid and lose the good performance of air cushion blanket

2. Resulting in uneven printing pressure. Under the action of tension, the rubber blanket is at different positions in the circumferential direction, where the tensile force of the rapid reduction of the specimen section is uneven, resulting in the uneven thinning of the thickness in the circumferential direction, resulting in the uneven printing pressure. The tighter the tension, the more uneven the r-the distance between the center of the test piece and the center of the rotating axis of the disc is serious. The non-uniformity of pressure causes the non-uniformity of ink transfer, which makes the field or flat background color that should be uniform become uneven, and the hue of color image shifts

3. affect the synchronous rolling state. Fine fruit under the normal tension of the blanket and the lining thickness of the rubber drum, the three rollers have a good synchronous rolling area state, so in the case of excessive tension, the synchronous rolling ratio of the rubber drum relative to the plate cylinder and the impression cylinder will rise, which destroys the synchronous rolling state, there is sliding between the three rollers, the correct transfer of the influence point, and the low carbon steel will yield when it is compressed, destroying the restoration of the layer and color

4. the creep and aging of rubber blanket are accelerated. The tighter the tension is, the more likely it will lead to conformational changes of rubber molecules, rigidity of molecular chains, and poor elasticity of rubber, which will affect the printing quality of products and shorten the service life of rubber blanket

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