The pen head balls used in oil-based ballpoint pens are mostly made of stainless steel or hard alloy materials. The size of the diameter of the ball determines the thickness of the writing line. Common ball diameters are 1 mm, 0.7 mm, and 0.5 mm (it is often indicated on the pen body or ballpoint refill of the product). Ballpoint pen ink is specially made, mainly mixed with colorant, solvent and viscosity modifier. Common colors are blue, black, and red. Ordinary 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 the word DA.
The oil-based ballpoint pen is the first generation 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 has mature production technology, stable product performance, long shelf life and stable writing performance. It has now become a traditional product variety in ballpoint pen products. The ink used in oily ballpoint pens has high viscosity, so the writing feel is relatively heavy .
