The temperature and humidity of the printing shop are important factors affecting product quality. If the temperature and humidity of the workshop are not controlled, the quality of printed products will be seriously affected and even production will not be possible.

Temperature and humidity affect the paper: paper is composed of plant fibers, and the plant fibers are porous and hydrophilic, and are very sensitive to water. The temperature and humidity of the environment will change slightly, and the moisture content of the paper will change. The relative humidity of the air affects the moisture content of the paper. Generally, the relative humidity increases, and the moisture content of the paper increases. Conversely, the relative humidity decreases and the paper moisture content decreases. The temperature change has different effects on the moisture content of the paper. Generally, the temperature rises and the moisture content of the paper decreases. The size of the paper's moisture content is directly related to printing performance. For example, changes in the moisture content of the paper can cause the paper to shrink (including local deformations). The dimensional stability of the paper and the suitability of the print job are closely related to the suitability of the print. As it is a multi-color overprint product, the paper size changes, will result in product overprinting is not allowed to become defective, waste products. Therefore, the size change of the paper due to the influence of temperature and humidity is one of the most important issues in the printing shop. Because of the change in the moisture content of the paper, it also causes changes in the other properties of the paper. If the water content increases, the tensile strength and surface strength of the paper will decrease; if the water content is too low, the paper will become brittle and harden, and the phenomenon of electrostatic charge will easily occur during printing.

The influence of temperature and humidity on the ink: The temperature and humidity that affect the ink the most is the drying speed. Various printing inks are affected by varying degrees of temperature and humidity. In general, the higher the temperature, the faster the drying; the lower the temperature, the slower the drying. In particular, during the printing process, the ink of the lithographic printing process may cause emulsification due to the existence of the fountain solution. Therefore, the relative humidity affects the evaporation of the moisture in the ink. Therefore, the temperature and humidity have a direct impact on the ink drying speed. If the temperature is too low, the relative humidity is too large, which will reduce the drying speed of the ink and the printing cycle of the director.

The temperature and humidity of the environment will also affect the viscosity of the ink. As the ambient temperature increases, the viscosity of the ink decreases; the ambient temperature decreases, and the viscosity of the ink increases. If the temperature is too low and the viscosity of the ink is too high, a printing failure may occur, such as partial peeling of the paper surface, sticking to the blanket or plate. Therefore, controlling the temperature and relative humidity of the printing press can control the drying speed of the ink and print failure.

Uncontrolled temperature and humidity will cause the substrate to generate static electricity: the temperature and humidity of the printing shop is too low, and the relative humidity is too low, which can cause the substrate to become electrostatically charged during the printing process. The consequences of static electricity, on the one hand, can cause difficulties in paper feeding and collection, and on the other hand it can cause printing failures and even cause fires due to discharge.

Workshop temperature and humidity generally controlled at: temperature -20 degrees Celsius +-1;

Relative humidity -55%-60%.