Abstract: An image forming apparatus includes a head to eject liquid droplets, a sub-tank having a container to store an amount of liquid supplied to the head, a negative pressure generator unit generating a negative pressure and an air introducing mechanism to introduce air, a main-tank to supply the amount of liquid into the sub-tank, a pressure detector unit to detect a pressure inside the sub-tank, and a controller to control an image forming operation using a remaining amount of liquid in the sub-tank while the main-tank is at an end status, where the controller determines whether the pressure inside the sub-tank is within a normal range, causes, if the detected pressure is not within the normal range, the air introducing mechanism to introduce air to raise the pressure inside the sub-tank, and causes the head to eject non-image forming liquid to cause the pressure to fall within the normal range.

Abstract: In an image forming apparatus, a control unit determines that dirt is present on the linear scale when a detecting unit detects a change in a moving direction of a moving member while the moving member is moving at a constant speed.

Abstract: An image forming apparatus includes a voltage applying unit to apply a voltage to and charge a surface of transport belt, a leak judging unit to judge a charge leak on the surface of the transport belt, and a recovery operation unit to perform a charge leak recovery operation in which the transport belt is driven in a state where the voltage applying unit applies no voltage to the transport belt, if the leak judging unit judges that the charge leak is generated on the surface of the transport belt. The leak judging unit again judges whether the charge leak is generated on the surface of the transport belt after the recovery operation unit performs the charge leak recovery operation.

Abstract: An image forming apparatus includes ink cartridges, image forming units, an ink-remaining-amount manager, a maintenance determiner, an information writer, an ink-amount estimator, and a maintenance-executability determiner. If an ink near-empty or empty state occurs in one of the ink cartridges due to image formation, the ink-amount estimator estimates an amount of ink required to execute the maintenance on the other ink cartridges based on the at least one of the need for and the type of maintenance determined by the maintenance determiner. If the maintenance-executability determiner determines that the maintenance is unexecutable on at least one of the other ink cartridges based on the required ink amount and a remaining ink amount, the maintenance-executability determiner determines that the unexecutable ink cartridge is at an ink near-empty or empty state and stops writing or updating information indicative of a spent state on the memory of the unexecutable ink cartridge.

Abstract: In an image forming apparatus, a control unit determines that dirt is present on the linear scale when a detecting unit detects a change in a moving direction of a moving member while the moving member is moving at a constant speed.