Patent ID: 7556341

Claim:
A liquid jet apparatus comprising: a liquid jet head having nozzle openings through which liquid drops are ejected; a liquid storage unit configured to store plural kinds of liquids to be fed to said liquid jet head; a plurality of valve units capable of respectively closing a plurality of liquid feed paths interconnecting said liquid storage unit and said liquid jet head for each kind of said plural kinds of liquids; a capping unit configured to seal a nozzle forming face of said liquid jet head and form a closed space; a negative pressure generation unit configured to exhaust said closed space formed by said capping unit and generate negative pressure in said closed space; and control means for controlling a switching operation for an open state or a closed state of said plurality of valve units and an exhaust operation for said closed space by said negative pressure generation unit so as to execute cleaning of said liquid jet head, wherein said control means has a function for executing a pressure reduction step of putting a valve unit corresponding to a kind of liquid to be cleaned among said plurality of valve units into an open state and simultaneously putting other valve units into a closed state, and in this state, exhausting said closed space by said negative pressure generation unit and generating a negative pressure state, and a negative pressure release step, after said pressure reduction step, of stopping exhausting by said negative pressure generation unit and releasing said negative pressure in said closed space with only said valve unit corresponding to said kind of liquid to be cleaned kept in said open state, and wherein said control means further has a function, at a stage that negative pressure remains in said closed space at said negative pressure release step, for executing a totally-opening step of switching said other valve units in said closed state into said open state and putting all said plurality of valve units into said open state.