Canon imagePROGRAF TX-3100 36" Printer with Basket - Manual (Page 816)

Documents are printed in monochrome
Check 1 Is Color Mode set to Monochrome , or Print Target set to Monochrome
(Photo) in a Windows printer driver?
In the Advanced Settings of the printer driver, specify Color in Color Mode and try printing again.
Check 2 Is Black and White Photo Print selected in a macOS printer driver?
Deselect Black and White Photo Print in the printer driver Quality & Media settings, and then print again.
Check 3 The print head nozzle may be blocked
Print a test pattern to check the color ink nozzles and see if they are clogged.
Checking for Nozzle Clogging
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