US Patent 10173434 Check valve, diaphragm pump, and printing apparatus

Provided is a check valve including: a duckbill valve; and a support member which is inserted into an inside portion of the duckbill valve, in which the duckbill valve includes a slit which is provided on a side where fluid is discharged, an inflow port which is provided on a side where the fluid flows in, and a flow path which connects the inflow port to the slit, and in which the support member is inserted into the flow path from the inflow port, a hole for sending the fluid to the slit when flowing in from the inflow port is provided, and the hole is provided so as to be hermetically sealed by the duckbill valve when a negative pressure is applied from the inflow port side.