US Patent 11850868 Circulation device

A circulation device includes first and second valves, first and second pressure measuring portions, a detection unit, and a controller. The first valve controls the flow rate of a liquid from a storage to a droplet discharge unit. The second valve controls the flow rate of the liquid from the droplet discharge unit to the storage. The first pressure measuring portion measures the fluid pressure of the liquid flowing between the first valve and the droplet discharge unit as a supply pressure. The second pressure measuring portion measures the fluid pressure of the liquid flowing between the second valve and the droplet discharge unit as a recovery pressure. The detection unit detects information related to the droplet discharge unit. The controller controls the first and second valves in accordance with the information detected by the detection unit and adjusts the supply pressure and the recovery pressure.