Difference between carbon ink & non-carbon ink:
Carbon ink is a special black pigment ink. The advantage is that it is particularly black and has a strong handwriting. This is also a common advantage of pigment ink. The disadvantage is that the carbon component is easy to precipitate, and then the pen is blocked, which is difficult to clean.
Non-carbon inks are not easy to block the nib, but the general color is not black enough compared to carbon ink, and the text is not stored for a longer period of time than carbon ink.