For multifunction printers, overall score is made up of:
Printing (80%) including print quality, speed and convenience. Scanning (10%)
Copying (10%)

For non-multifunction printers, overall score is simply an assessment of print quality, speed and convenience.

Extra ink used is the percentage of extra ink wasted for maintenance cleaning when printing 30 pages (text, graphics and photos) intermittently over 4 weeks, compared to the same printer printing 30 pages continuously.