Canon LBP7660Cdn Manual page 935

Set [Special Smoothing Mode] to [Mode 4].
If strip-shaped unevenness appears on images (photographs), diagrams,
gradations, or shaded patterns
Set [Special Smoothing Mode] to [Mode 5].
If the overall print result is not printed smoothly
Set [Special Smoothing Mode] to [Mode 6].
IMPORTANT
Precautions when setting [Special Smoothing Mode]
When [Mode 2] or [Mode 4] is selected, color unevenness may appear on a low color density
area.
When [Mode 3] is selected, color unevenness may appear on a low color density area and
shaded patterns.
When [Mode 5] is selected, characters, lines, and areas around diagrams may not be printed
smoothly.
When [Mode 6] is selected, color unevenness may appear.