A printing apparatus, comprising: a discharge head including a nozzle discharging an ink; a supply sub-tank storing the ink to be supplied to the discharge head; a collection sub-tank storing the ink collected from the discharge head; a supply pipe connecting the supply sub-tank and the discharge head, the supply pipe feeding the ink supplied from the supply sub-tank to the discharge head; a collection pipe connecting the discharge head and the collection sub-tank, the collection pipe feeding the ink collected from the discharge head to the collection sub-tank; a return pipe connecting the collection sub-tank and the supply sub-tank, the return pipe feeding the ink stored in the collection sub-tank to the supply sub-tank; a circulation pump provided to the return pipe, the circulation pump returning the ink collected to the collection sub-tank via the discharge head from the supply sub-tank to the supply sub-tank by feeding the ink from the collection sub-tank to the supply sub-tank; a buffer tank storing the ink; a collection pump provided to a pipe connecting the supply sub-tank and the buffer tank, the collection pump feeding the ink from the supply sub-tank to the buffer tank; a supply pump provided to a pipe connecting the buffer tank and the collection sub-tank, the supply pump feeding the ink from the buffer tank to the collection sub-tank; and a controller performing image printing to print an image on a printing medium by discharging the ink to the printing medium from the nozzle of the discharge head, wherein the controller performs an idle operation of controlling the collection pump and the supply pump so that the ink of an idle supply amount is supplied from the buffer tank to the collection sub-tank by the supply pump and the ink of an idle collection amount is collected from the supply sub-tank to the buffer tank by the collection pump before start of the image printing, and the controller performs a print starting operation of controlling the collection pump and the supply pump so that an amount of the ink collected from the supply sub-tank to the buffer tank by the collection pump decreases from the idle collection amount with the passage of time and an amount of the ink supplied from the buffer tank to the collection sub-tank by the supply pump is increased from the idle supply amount with the passage of time according to the start of the image printing. a discharge head including a nozzle discharging an ink; a supply sub-tank storing the ink to be supplied to the discharge head; a collection sub-tank storing the ink collected from the discharge head; a supply pipe connecting the supply sub-tank and the discharge head, the supply pipe feeding the ink supplied from the supply sub-tank to the discharge head; a collection pipe connecting the discharge head and the collection sub-tank, the collection pipe feeding the ink collected from the discharge head to the collection sub-tank; a return pipe connecting the collection sub-tank and the supply sub-tank, the return pipe feeding the ink stored in the collection sub-tank to the supply sub-tank; a circulation pump provided to the return pipe, the circulation pump returning the ink collected to the collection sub-tank via the discharge head from the supply sub-tank to the supply sub-tank by feeding the ink from the collection sub-tank to the supply sub-tank; a buffer tank storing the ink; a collection pump provided to a pipe connecting the supply sub-tank and the buffer tank, the collection pump feeding the ink from the supply sub-tank to the buffer tank; a supply pump provided to a pipe connecting the buffer tank and the collection sub-tank, the supply pump feeding the ink from the buffer tank to the collection sub-tank; and a controller performing image printing to print an image on a printing medium by discharging the ink to the printing medium from the nozzle of the discharge head, wherein the controller performs an idle operation of controlling the collection pump and the supply pump so that the ink of an idle supply amount is supplied from the buffer tank to the collection sub-tank by the supply pump and the ink of an idle collection amount is collected from the supply sub-tank to the buffer tank by the collection pump before start of the image printing, and the controller performs a print starting operation of controlling the collection pump and the supply pump so that an amount of the ink collected from the supply sub-tank to the buffer tank by the collection pump decreases from the idle collection amount with the passage of time and an amount of the ink supplied from the buffer tank to the collection sub-tank by the supply pump is increased from the idle supply amount with the passage of time according to the start of the image printing.