The writing principle of a ballpoint pen is mainly to use the ball to directly contact the paper surface to generate friction when writing, so that the ball rolls in the ball seat, and brings out the ink or ink in the pen core to achieve the purpose of writing.

A ballpoint pen is a pen that uses ink and different pigments to write. The nib is a small steel ball. The small steel ball is embedded in a small cylindrical copper bowl, and then connected to a plastic tube containing ink. The ink flows down from the surroundings as the steel ball rotates.

The pigment of ballpoint pen ink is dye. There are three main ink colors: blue, red, and black, of which blue ink is used the most. In the past, the pigment components in blue inks were salt-based royal blue and salt-based green lotus, and the solvents were oxidized castor oil and ricinoleic acid. Because basic dyes are not light fast (light fastness is only level 1-2), are not heat resistant, and are not resistant to acids and alkalis, they have poor durability and have been eliminated.

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 the normal use of oily ballpoint pens that are not mixed with 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 can be rotated inside. 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, and repeating this way can realize the function of a ballpoint pen.