Patent ID: 8197041
Filing Date: 2012-06-12
Classification: B41J

Abstract:
1. An image forming apparatus, comprising: a recording head to dispense ink droplets; a sub-tank to store ink to be supplied to the recording head, the sub-tank including: a main tank detachably mounted to the image forming apparatus, the main tank storing ink to be supplied to the sub-tank; a supply unit to supply ink from the main tank to the sub-tank; a memory to store data related to an image forming operation; and a controller to control an ink dispensing operation depending on image forming conditions, the controller being configured to determine whether a gas bubble intrudes into the sub-tank, set a gas history flag to a first value in a case that the controller determines that the gas bubble intrudes in the sub-tank, and set the gas history flag to a second value in a case that the controller determines that the gas bubble does not exist in the sub-tank, and store the gas history flag to the memory, wherein in a case that the controller determines that the main tank no longer contains ink and that ink supply from the main tank to the sub-tank is unable to be continued, and in a case that the gas history flag is set to the first value and is stored in the memory, the controller (a) sets a value for a dispensable ink volume, which is a threshold ink volume that is permitted to be dispensed from the sub-tank, to a first volume, the first volume being smaller than a second volume set in a case that the gas history flag is set to the second value, and (b) executes the ink dispensing operation from the recording head using ink remaining in the sub-tank, while prohibiting an atmosphere-communicating operation performed by the atmosphere-communicable unit.