The SU-320R plate roller ultrasonic hardness tester is a customized ultrasonic hardness tester specially developed by Dongjing for the plate making industry. The SU-320R solves the problem of inaccurate detection of the hardness of the copper plating layer and coating layer on plate rollers in portable devices such as the Leeb hardness tester. At the same time, due to the use of the ultra small force measuring head MP-200, it accurately detects the hardness of plate rollers without leaving obvious test marks on the plate rollers.