What is the difference between ipf 320M ink and ipf 321M ink? I have a Canon TM-350 printer. It takes 5 ink cartridges to print. 4 out of the 5 cartridges are ipf 320 (C,Y,B, MB). The fifth being Magenta requires 321M. Why? When the inks are sold in a set, they all came as ipf320 (C, Y, B, MB, and M) . What is the difference in 320m and 321m? Also, why would this printer not take 320M? Any advice or information would be greatly appreciated. Please and thank you.
