What is a biros ink made of?

Biro ink, commonly used in ballpoint pens, is primarily made of a mixture of dyes or pigments, solvents, and various additives. The solvent, often an oil or a wax-based compound, helps to maintain the ink's fluidity and viscosity, allowing it to flow smoothly through the pen's ballpoint. Additives may include surfactants to improve ink performance and stabilizers to enhance shelf life. This formulation results in a quick-drying, smudge-resistant ink that adheres well to paper.