Inkjet recording device

An inkjet recording device comprising:

• one, or more, recording head having a plurality of nozzles for ejecting ink onto a recording medium;
• an ink container for containing the ink supplied to the recording head;
• a first sub-tank for temporarily storing the ink supplied from the ink container;
• a second sub-tank for temporarily storing the ink supplied from the first sub-tank;
• a circulating pump for moving the ink from the first sub-tank to the second sub-tank;
• a pressurizing part for pressurizing interior of the second sub-tank to supply the ink from the second sub-tank to the recording head;
• a depressurizing part for depressurizing interior of the first sub-tank to circulate the ink from the recording head to the first sub-tank;
• a syringe into which the ink flows from the second sub-tank and from which the ink flows out toward the recording head, the syringe enabled to apply to the ink a maintenance pressure higher than a recording pressure applied to the ink by the pressurizing part;
• a first flow passage along which the ink flows from the first sub-tank to the circulating pump to the second sub-tank to the syringe and up to the recording head;
• a second flow passage along which the ink circulates from the recording head to the first sub-tank;
• and
• a third flow passage for coupling together an upstream side of the recording head in an ink flow direction of the first flow passage and a downstream side of the recording head in an ink flow direction of the second flow passage;
• an intermediate flow passage connected to a downstream point in the ink flow direction of the first flow passage so as to be communicated with the recording head and the second flow passage;
• and
• a communicating flow passage including a first branch flow passage for supplying the ink from the intermediate flow passage to the recording head, a second branch flow passage for circulating the ink from the recording head to the second flow passage, and a third branch flow passage for circulating the ink from the intermediate flow passage to the second flow passage, wherein
• the third flow passage as well as the first branch flow passage, the second branch flow passage, and the third branch flow passage composing the communicating flow passage are each equipped with an opening/closing valve.