Inkjet Printer

An inkjet printer comprising:

• a first inkjet head configured to eject an ink having a first viscosity onto a print medium;
• a second inkjet head configured to eject an ink having a second viscosity different from the first viscosity onto the print medium;
• a first ink tank in communication with the first inkjet head and configured to store the ink having the first viscosity;
• a second ink tank in communication with the second inkjet head and configured to store the ink having the second viscosity;
• a first ink air chamber in communication with an air layer in the first ink tank;
• a second ink air chamber in communication with an air layer in the second ink tank;
• a communicating pipe through which the first ink air chamber and the second ink air chamber communicate with each other;
• a first on-off valve provided in the communicating pipe and configured to open or close communication between the first ink air chamber and the second ink air chamber;
• an atmosphere open pipe connected to the second ink air chamber and opened to the atmosphere;
• a second on-off valve provided in the atmosphere open pipe and configured to open or close communication between the second ink air chamber and the atmosphere;
• a pressure adjuster configured to adjust a pressure in the second ink air chamber without intervention of the first ink air chamber;
• and
• a controller configured to control the first on-off valve, the second on-off valve, and the pressure adjuster, and configured to drive the pressure adjuster to increase the pressure in the second ink air chamber with the first on-off valve and the second on-off valve being closed.