Ink-jet printer and maintenance method for ink-jet printer

An ink-jet printer having a recording head which jets an ink onto a recording medium, comprising:

• an ink cartridge which stores the ink;
• an ink supply system which supplies the ink from an ink cartridge to the recording head;
• 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 first counter which counts a number of the recording medium on which the recording has been performed after the discharge mechanism discharged the ink previously;
• a consumption amount calculating section which calculates a first ink-consumption amount of the ink by multiplying an ink-consumption amount in which the ink is anticipated to be consumed for performing recording per unit number of the recording media, by the number of the recording media counted by the first counter;
• and
• a discharge amount determining section which determines an ink-discharge amount of the ink to be discharged by the discharge mechanism by subtracting the first ink-consumption amount of the ink from an ink-storing amount inside 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.

A maintenance method for ink-jet printer including an ink cartridge which stores an ink, a recording head which jets the ink onto a recording medium, and an ink supply system which supplies the ink from the ink cartridge to the recording head, the method comprising:

• discharging the ink inside the ink supply system;
• measuring an elapsed time elapsed after the discharging of the ink;
• calculating an ink-consumption amount, in which the ink has been consumed, based on a number of the recording media on which the recording has been performed after the discharging of the ink, if the measured elapsed time surpasses a predetermined time;
• determining an ink-discharge amount, in which the ink is to be discharged, by subtracting the ink-consumption amount from an ink-storing amount of the ink supply system;
• and
• discharging the ink in the determined ink-discharge amount, if a value of the determined ink-discharge amount is positive;
• 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 determined ink-discharge amount is more than zero, the determined ink-discharge amount of the ink is discharged and the same amount of the ink as the determined ink-discharge amount is supplied from the ink cartridge to the ink supply system simultaneously.