The importance of humidity in the printing process. In post-press processing, the impact of paper performance on printing is like a piano on music. The ideal environment for a piano is to prevent the strings from contracting and the speaker from deforming, thereby ensuring its crisp sound quality. In the printing and binding process, good paper performance means that the ink is uniform and clear, without sticking or dirt spots, the paper is flat and not curled, and the edges are wrinkle free. In high-speed printing, relative humidity is equally important as printing pressure. When the relative humidity drops to 25% to 35%, static electricity will be generated, causing the web to break. Paper, like the human body, is most suitable for temperatures between 65 and 80 degrees Fahrenheit and relative humidity between 40% and 55%. However, humans have stronger adaptability, and paper is more sensitive to changes in the environment. Therefore, it is important to carefully control the air conditioning system in the workshop. Baby, it's very cold outside. For example, there are some bulky newsprint rolls weighing up to one ton that have undergone pre-treatment in Canadian factories at 72 to 104 degrees Fahrenheit, relative humidity between 10% to 35%, and contain 8% moisture before being shipped or trucked to their destination (such as Chicago). They arrive at their destination in the cold season and are stacked in the warehouse, starting to thaw at around 70 degrees Fahrenheit. When the inside of the paper roll heats up, the moisture on the outside of the paper roll begins to be lost. From the warehouse to the unwinding room and then to the high-speed printing machine, the paper rolls experience fluctuations in temperature and humidity. 30 years ago, after establishing the Freedom Center, Chicago Tribune discovered the importance of using self wetting mist nozzles for humidification in the unwinding room. The reason why the spray nozzle is wet is that the center is an all electric power plant, and there is no additional electric driven humidification device. This type of wet mist nozzle can meet the all-round humidification needs. The wet mist or evaporation system can be directly installed in the factory or transmitted through the air conditioning system. In the northern United States, humidifying factories is undoubtedly an expensive investment, and it is important to make the company's finance department feel that this investment is profitable. Some printing factories in the north solve this problem by enclosing the space around the printing machines, isolating them from the large factory buildings, and only controlling the environment inside the enclosed space. This makes the space to be controlled smaller and more economical. In winter, people not only need to perform necessary humidity control, but also use activated carbon filtration devices to purify the air around machines. If there is a good air conditioning system, dehumidification in summer is not a problem. To understand the opposite situation in the scorching heat, one needs to visit a modern lithography factory in northern Carolina. The problem there occurred during the hot and humid weather from April to August. The factory specializes in printing school yearbooks, mostly using glossy paper. During the peak printing season every year, factories are plagued by dampness. The paper has become very sticky, and printing quality has become a challenge. In this case, the factory adopts a roof compressed air conditioning system, which consumes a lot of energy. To save printing costs, people often
