The uneven plastic deformation of the blanket

The pressure applied to the blanket during its use will cause different plastic deformations in the thickness of the blanket, which will lead to uneven thickness of the blanket. For example, after printing a product on the boot for a long time and then open the product, the product will then be reprinted. When printing 4 open products, the pressure between blanket cylinder and plate cylinder is evenly distributed over the entire blanket. However, the pressure between the blanket cylinder and the impression cylinder is not uniform due to the presence of the printed paper, and the position corresponding to the four sheets of paper is large. The pressure on the blanket is large, and the pressure on the position other than the four sheets is small or If there is no pressure, the plastic deformation of the blanket will occur at the position corresponding to the 4th paper, and the thickness will decrease. When the folio is reprinted, this position is prone to underpressure. Since this lack of pressure is caused by the partial depression of the blanket, even if the overall pressure between the rollers is increased, there can be no significant improvement, and the rubber can only be remedied by the method of repairing the rubber. This type of blanket cannot be used. High quality products are required. This non-uniform plastic deformation occurs with the following four factors:

1. Printing pressure. The greater the pressure, the greater the pressure on the blanket at the paper and the greater the plastic deformation that occurs, the more likely this non-uniform plastic deformation will occur. Therefore, when printing, the ink can transfer well. Brush pressure should not be too large, should use the best pressure printing.

2. The tightness of the blanket. The more tightly stretched, the thinner the rubber layer of the blanket and the worse the sensitivity and elasticity, the more likely it is that the plastic deformation is uneven.

3. Blanket performance. Due to the good sensitivity, elasticity, and recovery ability of the microbubble sponge layer, the air-cushion blanket is less prone to non-uniform plastic deformation.

4. Printing quantity. Long-term printing of a certain number of pages with a large number of prints will lead to greater local plastic deformation.

5. Paper and ink piles. After printing for a period of time, the surface of the blanket adheres to many papers and papers due to physical adsorption. If it is not cleaned in time, the thick paper and paper powder increase the local printing pressure, causing more plastic deformation locally. . When printing the cardboard, the paper scraps produced by the trimming of the trailing edge are likely to accumulate on the blanket over the edge of the cardboard with respect to the edge near the tip edge of the cardboard. Because of the uneven cutting of the cardboard, some of the printing is slight. When the cardboard is longer, piled paper pieces cause local depressions in the area. Therefore, it is necessary to pay special attention to cleaning the blanket in a timely manner when printing paper or cardboard that is susceptible to lint-free, powder-off, or chip-off. The dry ink is adhered to the impression cylinder, and the partial pressure is uneven during printing, resulting in the partial depression of the blanket. Therefore, after each type of product is printed and after printing is completed, the blanket should be cleaned in time. And impression cylinders.