RGB Pure Black Process

[On]*, [Off]
This setting enables you to specify how black and gray data with the equivalent ratio of R to G to B should be processed when device dependent RGB data is converted into device dependent CMYK data using the RGB source profile of the machine.

[On]

Black and gray data with the equivalent ratio of R to G to B is printed using the black (K) toner only, regardless of the selected [Output Profile] setting.

[Off]

Black and gray data with the equivalent ratio of R to G to B is printed using CMYK toners based on the selected [Output Profile] setting.
IMPORTANT
If you can see gradations or jagged lines in the printouts of black or gray data, select [Off] in RGB Pure Black Process and select [Normal] for [Output Profile].
NOTE
In combination with certain settings, black and gray data with the equivalent ratio of R to G to B may be printed using the black (K) toner only, even if you select [Off]. The following are examples.
When you select [On] for [Pure Black Text]
When you select [None] for [RGB Source Profile]
When you select [TR Normal] or [TR Photo] for [Output Profile]
When you select 'Use 100% GCR Profile' in the printer driver
If you select [None] for [RGB Source Profile], the RGB Pure Black Process setting is not applied.