The pen-tip balls used are mostly made of stainless steel or hard alloy materials. The diameter of the ball determines the thickness of the writing lines. Common ball diameters are 1 mm, 0.7 mm, and 0.5 mm (the product pen body or ballpoint pen refill is often marked). The ink of the ballpoint pen is specially made, mainly mixed with pigments, solvents and viscosity adjusters. Common colors are blue, black and red. Common inks are mostly used for general writing, and special inks are mostly used for file writing. The ink used for file writing is generally marked with a mark on the refill. For example, the domestic refill is marked with DA.
Oil-based ballpoint pens are the first product variety of the ballpoint pen series. It has been more than 60 years since it was put on the market in batches. After long-term improvement, the oil-based ballpoint pen production process is mature, the product performance is stable, the shelf life is long, and the writing performance is stable. It has become a traditional product variety in ballpoint pen products. The ink used in oil-based ballpoint pens has high viscosity, so the writing feel is relatively heavy. .
