| 摘要 |
PROBLEM TO BE SOLVED: To avoid that injection becomes impossible by certainly suppressing such a phenomenon that the positive pressure acts on a recording head through a cap when a piston is moved in an ink jet recording apparatus wherein ink is sucked from the recording head through the cap by moving the piston within a casing. SOLUTION: A pump has two pistons 58, 59 movable within a casing 57. In such a state that a cap comes into contact with a nozzle orifice surface, the pump chamber 76 between both pistons is expanded to such ink and, when one piston 59 moves in the direction closing a suction orifice 63, the other piston 58 is moved in the direction keeping or expanding the capacity of the pump chamber 76. By this constitution, when one piston 59 is moved, it is certainly avoided that positive pressure is generated in the pump chamber 76 and the sending of air into a recording head is prevented. |
