Patent ID: 8007070

Claim:
An ink-jet printer having a recording head which jets an ink onto a recording medium, comprising: an ink supply system which supplies the ink to the recording head from an ink cartridge storing the ink; a discharge mechanism which discharges the ink inside the ink supply system at a timing different from a jetting timing by which the ink is jetted onto the recording medium; a timer which measures an elapsed time elapsed after the discharge mechanism discharged the ink previously; a consumption amount calculating section which calculates an ink-consumption amount of the ink consumed after the discharge mechanism discharged the ink previously; and a discharge amount determining section which determines an ink amount of the ink which is obtained by subtracting the ink-consumption amount calculated by the consumption amount calculating section during a predetermined time period which is measured by the timer, from an ink-storing amount of the ink supply system as an ink-discharge amount in which the ink is to be discharged by the discharge mechanism from the ink supply system; wherein the ink cartridge is provided at an outside of a carriage provided with the recording head; wherein the ink supply system includes a sub tank which is provided on the carriage together with the recording head and a flexible tube which connects the sub tank and the ink cartridge; and wherein, when the ink-discharge amount determined by the discharge amount determining section is more than zero, the ink-discharge amount of the ink is discharged by the discharge mechanism and the same amount of the ink as the ink-discharge amount is supplied from the ink cartridge to the ink supply system simultaneously.