Some people have done statistics. There are more than 125 parametric variables that a lithographic offset press needs to control. Therefore, it is not an easy task to achieve even and constant offset printing. Prepress makers are always confident and even queasy to say that they can reliably output digital plates with an error of less than 5 microns. However, deviations may occur anywhere in the press room, which is a reality. In fact, as long as they adhere to the "best practices" in the printing process and resolutely implement the process control of the printing process, they can make the printing equipment perform better.
The special mention here is the problem of the ink roller hardness control of the printing press. The increase in hardness of the printer's ink roller will cause the following problems during the printing process.
1 too much tone value increase;
2 outlets have irregular edges;
The density of 3 dots is not uniform;
4 network ghost;
5 rough grainy dot area;
6 Poor results in the field;
7 increased mechanical ghosting;
8 The color is difficult to control during operation.
These are the problems we want to completely eliminate. However, the fundamental solution is to make the ink roller clean, with good ink receptivity and a soft surface. Every printer manufacturer and ink roller manufacturer has its own ideas and suggestions. For commercial printing companies, if you want to be able to print high-quality paper (plate paper) on their presses and can also print ordinary paper (non-coated paper), then you should pay attention to the press manufacturer's each ink roller of the printing press Recommended hardness (Shore hardness). Some manufacturers will give different hardness values ​​according to the different functions and positions of the ink roller, while other manufacturers use the same hardness for all ink rollers. After you have determined the correct ink roller hardness for your press, try to maintain this hardness index.
Since the rollers will harden under ultraviolet, high temperature and ozone conditions, keep the rollers away from sunlight and store them in a dark environment, keeping them away from heat sources and away from the motor.
It is advisable to maintain the softness of the ink roller by using a decalcification solution or a cleaning solution made of hot water and 15% acetic acid at least once a week in order to wash off any calcium deposits on the roller. In addition, on the weekends, a gentle cleaning operation with commercially available ink cleaners is used to keep the ink roller clean throughout the weekend. When you go to work on Monday, you should also apply more ink cleaner on the roller and rinse it. Do not use harsh chemical solvents on the roller as much as possible, and never scrub on the roller with the wire cleaning pad. The ideal situation is to remove the ink roller from the press every quarter for manual cleaning, while also cleaning all the ink roller support parts and the side wall board of the press. This may take some time and effort, but it can eliminate ringworm and improve the quality of printing. Why not?