Patent ID: 8919911
Filing Date: 2014-12-30
Classification: B41J

Abstract:
1. An image forming apparatus comprising: a recording head to eject droplets of liquid; a head tank to store the liquid to be supplied to the recording head; a main tank to store the liquid to be supplied to the head tank; a reversible liquid feed device disposed between the main tank and the head tank; a controller to control the liquid feed device to feed the liquid from the main tank to the head tank and in reverse from the head tank to the main tank; an air release unit disposed at the head tank to open an interior of the head tank to an atmosphere; and a liquid level detector to detect a liquid level of the liquid in the head tank, wherein, when the main tank is in an ink end state and in any of a case that the controller determines that in the head tank a remaining amount of liquid is large and an amount of air is small and a case that the controller determines that in the head tank the remaining amount of liquid is small and the amount of air is large, the controller causes the liquid feed device to feed a reverse feed amount of the liquid in reverse from the head tank to the main tank with the air release unit opened to release an interior of the head tank to the atmosphere, when air is unlikely to be mixed with the liquid in the head tank or the liquid is unlikely to be bubbled in the head tank before a new main tank is installed in replacement of the main tank, the controller causes the liquid feed device to feed the liquid from the main tank to the head tank with the air release unit opened after the new main tank is installed in replacement of the main tank; and when air is likely to be mixed with the liquid in the head tank or the liquid is likely to be bubbled in the head tank before the new main tank is installed in replacement of the main tank, the controller causes the liquid feed device to feed a predetermined amount of liquid equal to or greater than the reverse feed amount from the main tank to the head tank with the air release unit closed after the new main tank is installed in replacement of the main tank.