In the offset printing process, the back of the newspaper is often dirty. This phenomenon generally occurs in places where the amount of printing ink is relatively large, and is often caused by indirect contact with newspapers or slow drying. According to past experience, there are generally several reasons why the newspaper is dirty and the back is dirty.

1. When printing coated paper or paper with a relatively smooth surface, when the amount of ink is large at the site and the dense dot, smearing may occur during the stacking process.

2. Operators are not properly handling newspapers, especially when they hit the newspapers, because of the large ink and stickiness.

3, ink drying speed is too slow, easy to stick dirty.

4, the ink is too thin, if the ink is too large, easy to stick dirty.

Solution:

1, in the premise of meeting the printing requirements, try to reduce the amount of ink.

2. When printing glossy paper with poor absorption, always wipe all the paper guide rollers.

3. Add some varnish to the ink properly during printing to avoid paper pulling.

4. When arranging the printing color sequence, try to place the full version on the ground in the last color group so as to reduce the links of the printed products.

5. Regularly wipe the paper guide roller and the triangle, where it is the key to the dirty newspaper.




Source: Shenzhen Printing Network