In printing plants, ink is the main raw material. The difference between it and printing materials is that its quality and the amount of surplus (opened) are closely related to the way of use and on-site management. The printing materials with poor quality can be returned at any time, but the ink is often not of poor quality, but there is too much left. It is a pity to throw away these left ink, but it is not easy to use it again, and it will not be used much, resulting in the backlog and waste of funds. How to effectively manage the ink and control the amount of residual ink is a problem that many printing plants have to face, and the benefits of management are obvious on this issue