Parker's pen adopts a slender traditional tongue design, and an elbow extends from the end of the tongue, and the end of the elbow bends towards the wall of the ink reservoir and clings to the wall. Parker has an exclusive patent on this design. Theoretically, this will make the ink flow back to the ink reservoir along the elbow when the pen is not used. /kloc-The competition in the pen market in the 1920s was fierce, and the "lucky curve" was Parker's advantage.

Common colors of ink are red and black, such as ink and blue and black. Red ink is generally used to correct homework, and its application scope is small. Blue-black ink turns blue first and then black, which is not easy to fade and writes smoothly. It is used for writing in study and work. Extended data:

Ink should be the same brand and color, and cannot be mixed; Otherwise, precipitation will occur, which is not good for writing. After each writing, put on the pen cap in time; Otherwise, the ink on the pen tip will dry, and the water will not be smooth when writing again. If you want to use another ink, you should wash your pen and dry it before loading new ink.

The main purpose of adding stabilizer to ink is to eliminate the precipitation of ink and avoid the phenomenon of water shortage when writing. Commonly used stabilizers are sulfuric acid (H2SO4), oxalic acid (HOOCCOOH) and formaldehyde (HCHO) solution. These stabilizers have certain acidity, which lays a hidden danger for paper acidification and should not be used more.

Self-citation and utilization: Baidu Encyclopedia-Ink