Patent ID: 8256855

Claim:
A method for confirming an ink circulation path, the ink circulation path including: at least one recording head which ejects ink to form an image; an upstream side tank with the ink filled therein; a downstream side tank with the ink filled therein; a first ink path which connects between the upstream side tank and the recording head; a second ink path which connects between the recording head and the downstream side tank; a third ink path which connects between the downstream side tank and the upstream side tank; and a sensor which detects a displacement amount of a parameter varying in response to an amount of ink in the downstream side tank, the ink circulating again to the upstream side tank in order of the upstream side tank, the first ink path, the recording head, the second ink path, the downstream side tank, and the third ink path, the method comprising: a first ink supply process of supplying ink in the upstream side tank toward the downstream side tank through the first and the second ink paths; a second ink supply process of supplying ink in the downstream side tank toward the upstream side tank through the third ink path with a supply amount which is larger than a supply amount of ink in the first ink supply process; an ink supply stop process of stopping the second ink supply process when the displacement amount of the parameter is detected, and when it is detected that the parameter changes from a first value to a second value which is smaller than the first value by detecting the displacement amount of the parameter while performing the first ink supply process and second ink supply process; a time measurement process of measuring a time until the parameter returns to the first value from execution of the ink supply stop process; and a comparison process of comparing whether or not a measured time in the time measurement process is not longer than a prescribed set time.