When the Ci flexo printing machine manufacturer formulates the repair and maintenance manual, it is often mandatory to determine the water quality of the water circulation system every year. The main items to be measured are iron ion concentration, etc., which is mainly to monitor the formation of scale in the pipeline. Once scale is formed on the inner wall of the central impression cylinder, the thermal conductivity will change, and the entire temperature control system will not be able to guarantee the control accuracy. When the water quality exceeds the specified standard, the Flexo printing machine must adopt a water treatment method to restore the circulating water quality to the normal value.