Canon GP-300 Online Manual page 670

Ink is automatically agitated after specified intervals to maintain optimal print quality. Agitation takes
approximately 1 minute 30 seconds.
Ink is also agitated automatically at the following times. Please note that no other operations can be
performed while "Agitating the ink" is on the touch screen.
◦ After the printer is turned on
◦ After data transmission
◦ After ink tank replacement
In other cases, contact your Canon dealer.
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