Patent ID: 8317282
Filing Date: 2012-11-27
Classification: B41J

Abstract:
1. An image forming apparatus comprising: a recording head configured to eject liquid droplets; a sub-tank having a liquid container configured to store an amount of a liquid to be supplied to the recording head, a negative pressure generator unit configured to generate a negative pressure inside the sub-tank and an air introducing mechanism configured to introduce outside air into the liquid container; a main-tank containing the liquid and configured to supply the amount of the liquid into the sub-tank; a pressure detector unit configured to detect a pressure inside the sub-tank; and a controller configured to control an image forming operation using a remaining amount of the liquid in the sub-tank while the main-tank is at an end status, wherein the controller determines whether the pressure inside the sub-tank detected by the pressure detector unit is within a predetermined normal range, causes, if the detected result of the pressure inside the sub-tank is not within the predetermined normal range, the air introducing mechanism of the sub-tank to open and introduce outside air into the sub-tank to raise the pressure inside the sub-tank, and causes the recording head to carry out non-image forming liquid droplet ejection to control a negative pressure generating operation to cause the pressure inside the sub-tank to fall within the normal range.