Along with upgrading of paper quality and diversification of paper kinds, the requirements for paper quality are diversified, and especially for printability, this trend is remarkable. Generally, the size press is provided with two rollers to coat size liquid on the surface to increase the surface strength of a wet paper at the press part of the paper making machine, after dewatering press, or to improve printability. The inclined type is more effective and of lower cost than the conventional inner sizing type using beater additive. In addition, the size press is widely used at the process of on-machine coating for application of primer for topcoat, bearing an important role to improve paper quality and printability. This test size press can simulate as many conditions as possible of a practical paper making machine, using an excellent system with ease of handling, and ensuring high reproducibility. The mechanism is designed as follows; this is an inclined type press with two rollers of special material being laid at an inclination of 35 degrees. From the liquid tank, the size liquid is fed through a pipe onto the rollers, forming a dam of liquid between them. Between the rollers in such a state, is inserted the paper sheet semi-dried or dried (sizeless), then immediately the paper sheet is pressed in the roll nip.