If the reflector is not installed, about 80% of the UV light cannot reach the surface of the printed matter due to diffusion. Therefore, the UV lamp must be installed with a lamp cover to make the UV light reflect and concentrate on the surface of the printed matter. At the same time, it is also necessary to clean and maintain the reflector at any time. If the paper powder or spray powder is attached to the reflector, it will affect the reflection efficiency of the UV lamp. If the UV lamp is not used for a long time, the UV lamp cover should also be closed to prevent dust from entering.

The offset printing machine can be divided into monochrome, two-color, four-color and multi-color printing presses according to the number of printing colors completed by one paper feeding. It can be divided into small offset printing presses, six open, four open, half open and full sheet paper printing presses according to the maximum paper size of the printer. In addition, there is a double-sided printing press that can complete two side printing at the same time by one paper feeding. According to the fountain system, it can be divided into alcohol machine (i.e., alcohol fountain offset press, water wheel (i.e., water fountain offset press) and water free offset press.