Inkjet printing apparatus and ink supplying method

An ink supplying method used for an inkjet printing apparatus for performing printing on a printing medium by using a printing head for ejecting ink, said method comprising the steps of:

• providing an inkjet printing apparatus having:
• a first ink tank serving as a source of the ink;
• a second ink tank which can be charged with the ink from said first ink tank and which supplies the ink to said printing head during printing;
• and
• ink transport means for charging said second ink tank with the ink from said first ink tank,
• wherein in relation to the direction of gravity in an orientation upon using said printing apparatus, a port of a channel located at a side of said second ink tank for supplying ink from said first ink tank to said second ink tank is arranged relatively high position and an ink outlet port for supplying the ink from said second ink tank to said printing head is arranged relatively low position respectively, and a port of said channel located at a side of said first ink tank is arranged to position at the bottom of said first ink tank;
• and
• wherein the ink transport means can return the contents of said second ink tank to said first ink tank, and in relation to the direction of gravity in an orientation upon using said printing apparatus, a starting point of a channel for the returning is in a relatively high position on said second ink tank in relation to the direction of gravity and a starting point of the channel for supplying the ink to said printing head is in a relatively low position on said second ink tank in relation to the direction of gravity;
• charging said second ink tank with the ink from said first ink tank by increasing the internal volume of said second ink tank;
• and
• returning the contents of said second ink tank to said first ink tank by reducing the internal volume of said second ink tank.