On each lithographic press, there are 125 variables that need to be controlled, so maintaining print consistency becomes a difficult goal. Excessive hardness of the rollers on the press may give you the following problems: large increase in tone value, uneven dot density, increase in mechanical ghosting, failure of color control, unevenness at the edges of the dots, blurring of the dots The granulation of the halftone pattern and the printing effect of the solid color block are not satisfactory.

In order to avoid these problems, the printer operator must ensure the cleanliness, ink absorption and softness of the drum. I might read the hardness requirements of the press manufacturer for each roller. Some manufacturers may impose different hardness requirements on rollers depending on their function and their position on the press, while some manufacturers may offer the user a hardness value for all rollers. Now you have to choose the right hardness value for your printing cylinder and try to keep it as long as possible.

The drum hardens when exposed to ultraviolet light or in an environment that is exposed to high temperatures and susceptibility to oxidation. Therefore, it is best to store the rollers in a dark place and keep them away from heat sources and electric motors.

To keep the rollers of the press soft, it is best to clean them once a week with decalcifying solution or hot water containing 15% vinegar. In addition, every weekend, the operator should thoroughly clean the drum with an ink roller cleaner and rinse the drum once a week on Monday morning. If possible, try to avoid using chemicals on the rollers and be sure not to use steel pads. Ideally, it is best to remove all the rollers on the press every other quarter for a manual cleaning, while also cleaning the brackets and frames of the press. This is a daunting task, but as long as you work hard, you will be able to see the disappearance of stains and the improvement of print quality.