Canon PIXMA iP2850 - Manual (Page 220)

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Cause
The ink has run out.
Action
Replace the ink cartridge and close the cover.
If printing is in progress and you want to continue printing, press the printer's ON/RESUME button for at
least 5 seconds with the ink cartridge installed. Then printing can continue under the ink out condition.
The function for detecting the remaining ink level will be disabled.
Replace the empty ink cartridge immediately after the printing. The resulting print quality is not
satisfactory, if printing is continued under the ink out condition.
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