Pad printing is a special printing process. It can print characters and patterns on the surface of irregular substrates. At present, it has become an important printing method widely used.

In daily life, many characters and patterns on the surface of plastic shells are brushed by pad printing technology. In addition, pad printing can be competent for the surface printing of many products such as computer keyboards, industrial instruments and meters. However, the application range of pad printing in silica gel products is relatively small. Generally, only the conductive ink of conductive adhesive keys will adopt pad printing, and the operation mode is also different from ordinary pad printing.

Before pad printing, the designed pattern needs to be etched on the printing lithography, usually on the steel plate. Then the pad printing ink is evenly coated on the pattern part of the steel plate, and finally the ink of the steel plate pattern part is transferred to the surface of the substrate by using the silicone rubber pad printing rubber head. Generally, pad printing can only print one color at a time. Therefore, if there are several colors in the design of pattern content, several steel plates need to be made, and each color should be colored and printed separately. When the pad printing machine is working, it is first necessary to evenly coat the ink on the steel plate. After starting the pad printing machine, the ink scraping steel knife will scrape off the excess ink other than the characters on the steel plate. At this time, the silicone pad printing head drops onto the steel plate and sticks the ink on the character pattern to the silicone pad printing head. Finally, the pad printing head is moved above the substrate and lowered to transfer the ink on the surface of the silicone pad printing head to the surface of the substrate, so as to repeat.

Due to the softness of the silicone head for pad printing, pad printing can complete the printing of the surface of a large convex or concave substrate that cannot be completed by silk screen printing. Also due to the softness of the silicone head, pad printing usually prints the surface of products with high hardness, and the surface printing of silicone products with general hardness is completed by silk screen printing.