Inkjet printing machine

An inkjet printing machine comprising:

• an inkjet head;
• an ink cartridge that holds ink therein;
• an ink route that connects the ink cartridge to the inkjet head;
• a branch route with one end connected to a branching point on the ink route and the other end connected to a joining point on the ink route, the joining point being on an inkjet head side viewed from the branching point;
• a pump that is disposed on the branch route, and used to send ink from the ink cartridge to the inkjet head;
• a first valve that is disposed on a direct route which is a route between the branching point and the joining point on the ink route, and opens and closes a channel for a fluid within the direct route;
• a second valve disposed on an inkjet head side viewed from the joining point on the ink route, and opens and closes a channel for a fluid within the ink route;
• and
• a controller configured
• (i) to drive the pump with the first valve closed and the second valve opened in initial filling of the inkjet head with ink,
• (ii) to close the second valve on or after a time point when a tip of ink introduced in the ink route reaches a prescribed position between the joining point and the second valve,
• (iii) to stop the pump and to open the first valve after closing the second valve,
• (iv) to close the first valve and to open the second valve after the ink, which flows backward due to restoration of compressed air between the second valve and the ink, moves air in the direct route into the ink cartridge, and
• (v) to drive the pump to fill the inkjet head with ink.