Ink jet apparatus including means for regulating an amount of ink and an amount of air in an ink tank relative to each other

Claim 1

An ink jet recording apparatus comprising: an exchangeable head portion for discharging ink to form an image; an intermediate ink tank for storing ink to be supplied to said head portion, said intermediate ink tank containing an amount of ink and an amount of air; a main ink tank for supplying ink to said intermediate ink tank; an ink supply tube connected between said main ink tank and said intermediate ink tank; a scanning carriage mounting said head portion and said intermediate ink tank; and suction means for regulating the amount of said ink and the amount of said air relative to each other in said intermediate ink tank by moving into and out of contact with said intermediate ink tank, said suction means including a cap provided with a projection portion and a pump connected to the cap for sucking the ink and the air in the intermediate ink tank, wherein an opening is provided in said intermediate ink tank and can be coupled to said suction means, the opening being located above said ink supply tube connected to said intermediate ink tank and covered by an opening/closing mechanism which opens when said suction means is in contact with said intermediate ink tank, said opening/closing mechanism including a ball for sealing the opening and a spring connected to said ball which biases the ball toward the opening, and the ball is pressed by the projection portion of the cap by contacting the cap to the opening, so that said ink and said air are sucked from said intermediate ink tank by the pump as a result of the projection portion pressing on the ball.