The "424" blue ballpoint pen and "322" black ballpoint pen sold in the market have better handwriting durability. There are frequent reports of toxic scented ballpoint pens. The volatile organic compounds contained in inferior scented stationery are toxic and harmful to the human body. However, there have not been any incidents of poisoning caused by normal use of oily ballpoint pens without volatile organic compounds.

The main structure of the ballpoint pen is the upper and lower teeth column, the upper teeth column is pressed by hand, and the lower teeth column is the inner rotatable. The meshing of the upper and lower tooth columns is incomplete meshing, only the tips of the teeth bite partly, and the guide ribs behind the two biting teeth are designed to slide in the same guide groove. When the lower tooth column pushes on the upper tooth column and slides out of the guide After the slot, due to the action of the spring, the teeth of the lower shank will slide along the inclined surface of the meshing upper shank teeth, so that under the action of the inclined surface, the lower shank will rotate through an angle and slide to the other side To go, it is pressed down, so repeating can realize the function of a ballpoint pen.