JJG (Light Industry) 55-2000 "Paper and Cardboard Absorbency Tester" standard specifies the method of verification of paper and Cardboard absorbency tester, which is suitable for initial verification of new instruments, inspection in use and verification after maintenance. The instrument is designed according to the Cobb (Cobb) method for measuring the surface water-absorption of paper. The standard specifies in detail the appearance of the instrument, the geometric size and mass of the pressing roller, and the absorption area error. The verification items include Appearance inspection, sealing test, water column height accuracy, absorption area error and the size and mass of the pressing roller. The instrument needs to be verified in a specific environment using standard Measurement equipment to ensure that it meets the technical requirements. Qualified instruments will receive a verification certificate, and the verification period is usually one year.