Because the small ball can rotate to write, the principle is that when writing, the ball can rotate, and the side facing the paper is resisted, and the side facing the ink will rotate to the other side of the paper. Over and over again, no matter how the pen tip rotates, there will be an ink surface to write.

When writing with a ballpoint pen, it is ideal to control the angle between 55 and 70. At this time, only the ball contacts the paper (the ball is hard, tungsten carbide or ceramic, which is not easy to wear), and the closed part does not contact the handwriting, which ensures that the service life of the ballpoint pen can be prolonged in a good writing state.

Extended data:

The ball of the nib needs to be made of hard and wear-resistant materials. The most commonly used materials are stainless steel and tungsten carbide, the latter being of better quality. Tungsten carbide is a compound composed of tungsten and carbon, which belongs to the production material of cemented carbide. It is a black hexagonal crystal with hardness similar to that of diamond and stable chemical properties. It is a good conductor of electricity and heat.

There are marks and signs such as trademark number, model, manufacturer's name, place of origin, quality inspection certificate, etc. on the commodity packaging. Fake and shoddy goods, the ink filled in the refill is not the archival ink approved by the National Archives Bureau, and there is no "DA" mark on the refill, and there is no trademark number, model, factory name and place of origin. Some are unlicensed refills smuggled in from abroad, which are assembled to pretend to be imported high-grade ballpoint pens.

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