Canon PIXMA iP8500 Series Quick Start Manual page 60

Printing Maintenance
(5) Read the message and click Print Check Pattern to print the nozzle check pattern.
The nozzle check pattern is printed.
4
Check the Print Head condition with the printed nozzle check pattern.
See "Printing the Nozzle Check Pattern"
56
Do not perform any other operations until the Print Head Cleaning
finishes. This takes about 70 seconds.
Clicking Initial Check Items displays the items to be checked before
cleaning.
The nozzle check pattern will not be printed correctly if there is not
enough ink. Replace the ink tank if the remaining amount of ink is
insufficient.
See "Replacing an Ink Tank"
If the problem remains after performing step 1 to 4 twice, try Print Head
Deep Cleaning.
See "Print Head Deep Cleaning"
on page 49.
on page 42.
on page 57.