The Canon MC-01 Maintenance Cartridge is a necessary component of
the imagePROGRAF W6400 professional large format printer. It serves as
the receptacle for waste ink during cleaning and normal startup
subroutines, and is required for operation. Periodic exchange of the
MC-01 assures the highest quality printing results with your
imagePROGRAF W6400 printer. Your printer's software will indicate the
status of your MC-01, and for best results it should be exchanged at
~80% capacity.