Canon LBP 660 - B/W Laser Printer Service Manual page 249

Device Settings Tab
This tab specifies how halftones are handled when you print graphics.
The LBP-660 can print using either the printer's own halftones or the Microsoft Windows
NT system halftones. To select the halftones used, click on the Halftone option and then
use the "Change 'Halftone' Setting" option buttons to select the halftones you want to use.
If you select "Use System Halftone", you can use the Device Color/Halftone Properties
dialog box to change the system halftone settings. For information on changing the system
halftones, refer to the help or the Microsoft Windows NT manuals.
The operation of the Halftone Color Adjustment setting in the Document properties
changes depending on the halftone handling selected here.
Chapter 4 Using the Microsoft Windows Printing System 15