In order to improve the smoothness of writing, what substance is added in the production process of gel pens?

In order to significantly improve the smoothness of writing, lubricants are introduced into the production process of gel pens. This lubricant, often referred to in the industry as a “follower sealant,” or more colloquially as a “lithium ester” or “tail plug oil,” plays multiple roles. First of all, as an efficient sealant, it tightly seals the ink inside the gel pen, effectively preventing the ink from deteriorating due to evaporation, moisture absorption or oxidation, thereby extending the service life of the ink and keeping the ink color bright and stable.
Lubricants play a vital role in facilitating writing. When the user starts writing and the moment the pen tip touches the paper, the lubricant responds quickly, pushing the ink out of the pen tip smoothly with almost no delay. This process benefits from the low viscosity of the lubricant, which can use atmospheric pressure as a booster to help the ink flow evenly and steadily along the pen core to the pen tip, ensuring a continuous and smooth writing experience every time you put pen to paper.
In addition to the use of lubricants, the nib design of the gel pen also has an important impact on the writing experience. The pen tip is usually carefully crafted from high-quality metal, plastic or ceramic materials. These materials are not only wear-resistant and durable, but more importantly, they can greatly reduce the friction when the pen tip contacts the paper. The carefully designed pen tip shape and edge treatment allow the ink to be evenly distributed on the paper, avoiding uneven line thickness or ink breakage caused by uneven ink distribution, further improving the smoothness of writing and the beauty of handwriting.
In addition, the ink formula of the gel pen is also an important factor in achieving smooth writing. The viscosity of the ink is precisely controlled within the ideal range between water and oil. This viscosity ensures good fluidity of the ink while avoiding penetration problems caused by being too thin, making the writing clear and clean.