Too tight a blanket

The blanket must be tight on the blanket cylinder with proper tension. If the blanket is too loose, when the blanket is imprinted, displacement occurs under the action of the pressing force and cannot be reset in time. This can cause ghosting failure. If the blanket is stretched too tightly, there will be many drawbacks:

1. The adhesive layer is thinned and its elasticity is reduced. If the printing pressure is calculated by measuring the thickness obtained by the micrometer in the field state of the blanket, then the printing pressure may be insufficient due to the excessive thinning of the adhesive layer. The thinning of the strand reduces the elasticity of the blanket, and even if the center-to-center distance is reduced to increase the amount of compression, poor ink transfer may occur. If it is an air-cushioned blanket, too tight a stretch may also cause the microbubble sponge layer to fail and lose the good performance that the air-cushion blanket should have.

2. Causes uneven printing pressure. Due to the tightening force, the pulling force of the blanket at different positions in the circumferential direction is not uniform, so that the thinning of the thickness is not uniform in the circumferential direction, resulting in uneven printing pressure. The tighter the tension, the more serious this unevenness is. The non-uniformity of the pressure causes unevenness in the ink transfer, so that the background color of the solid or flat screen that should otherwise be uniform becomes non-uniform, and the hue of the color image shifts.

3. Affects the synchronous rolling state. Fine fruit under normal blanket tightness and rubber blanket lining thickness, the three rollers have a good state of synchronization of the rolling zone, then in the case of excessive tension, the rubber roller relative to the plate cylinder and the impression roller synchronization The rolling ratio will rise, destroying the state of simultaneous rolling, sliding between the three rollers, affecting the correct transfer of dots, destroying the reduction of levels and colors.

4. Accelerated the creep and aging of the blanket. The more tightly stretched, the more likely it is to cause conformational changes in the rubber molecules, which will stiffen the molecular chains and deteriorate the elasticity of the rubber, affecting the printing quality of the product and shortening the service life of the blanket.