Ink pen, gel pen, oil pen, ballpoint pen, signature pen and carbon pen have different experience, writing principle and applicable scenes. The following are their differences:

1. Ink pen: Use water-based pen and ink, the ink is smooth, but you can't write on carbon paper or oily substances. Disposable pen, using the capillary principle of pen, writes with neutral pen head.

2. Gel pen: Using water-based pen ink, the ink is smooth, but you can't write on carbon paper and oily substances.

3. Oily pen: Also called ballpoint pen, the ink used is oily pen and ink, which is not smooth to oil, but has special uses, such as copying and writing on oily surfaces.

4. Ballpoint pen: Oily pen and ink are used, which are not smooth, but have special uses, such as copying and writing on oily surfaces.

5. Signature pen: Use water-based or oily ink, which is slightly thicker than ink pen. The written words are beautiful, but they feel better.

6. Carbon pen: The water-based ink with fiber head is called carbon pen, and now the gel pen with carbon ink is also called carbon pen, which is used for signing or marking.

To sum up, these pens have their own characteristics in writing experience, writing principle and applicable scenes. When choosing which pen to use, you can choose according to your own needs and scenes.