Canon MultiPASSTM C50 User Manual page 233

3. If the document is light, blank, or shows gaps, clean the printing area. If this
doesn't work, replace the cartridge.
Although Canon makes numerous BJ cartridges, the BC-21/21e Colour BJ
cartridge, the BC-20 Black BJ cartridge, the BC-22/22e Colour Photo BJ
cartridge, and the BC-29F Fluorescent BJ cartridge are designed specifically for
Canon's colour BJ printers, and are the only ones Canon recommends.
Also, the BCI-21 Colour and BCI-21 Black ink tanks are designed specifically for
the BC-21/21e Colour BJ cartridge, and are the only ones Canon recommends for
the BC-21/21e.
Chapter 9 Maintaining Your MultiPASS C50 9-11