Try not to use the hero's own carbon ink, which is easy to block the pen.

If you want to use carbon, you can consider Beijing carbon ink and wash your pen once a month.

Non-carbon ink can be used at will without these restrictions. Better quality inks include:

Belle Gold 400 1 Ink, Catfish Ink, Eternal Black, Extremely Black, Diamine Ink, Sewei, etc.

Of course, these inks are also very expensive. ...

Recommendation: Catfish ink is always black and has strong waterproof performance; 400 1 black is not waterproof, but the comprehensive price is better.