Inkjet recording apparatus

1. An inkjet recording apparatus comprising:

a recording head of an inkjet type including

an introduction section of introducing liquid into the recording head,

a discharge section of discharging the liquid that has circulated through an interior of the recording head, to an exterior of the recording head, and

a plurality of nozzles from which droplets of the liquid are ejected;

a first liquid chamber connected to the introduction section of the recording head;

a second liquid chamber connected to the discharge section of the recording head;

a buffer tank which is connected to the first liquid chamber and the second liquid chamber, and an interior of which is open to air;

a liquid supply source which is connected to the buffer tank;

a first pump which moves the liquid in both directions between the first liquid chamber and the buffer tank;

a second pump which moves the liquid in both directions between the second liquid chamber and the buffer tank;

a pressure determination device which determines internal pressures of the first liquid chamber and the second liquid chamber; and

a pressure control device which sets respective target pressures of the first liquid chamber and the second liquid chamber in such a manner that a prescribed back pressure is applied to the liquid inside the plurality of nozzles of the recording head while a prescribed pressure differential is provided between the first liquid chamber and the second liquid chamber, and controls driving of the first pump and the second pump in accordance with determination results of the pressure determination device so as to control pressures in the first liquid chamber and the second liquid chamber in such a manner that the internal pressures of the first liquid chamber and the second liquid chamber remain constant at the target pressures respectively,

wherein the buffer tank has a circulation flow channel, at least one of a filter and a deaeration device is provided in the circulation flow channel, and the liquid in the buffer tank is circulated to the buffer tank via the at least one of the filter and the deaeration device provided in the circulation flow channel, a flow outlet of the at least one of the filter and the deaeration device being directly connected to a flow inlet of the buffer tank.

2. The inkjet recording apparatus as defined in claim 1 , wherein the buffer tank has a temperature adjustment function.

3. The inkjet recording apparatus as defined in claim 1 comprising a first sub tank and a second sub tank, wherein

the first sub tank has a first closed container containing a first gas chamber and the first liquid chamber which are separated by a first flexible film, and

the second sub tank has a second closed container containing a second gas chamber and the second liquid chamber which are separated by a second flexible film.