Ballpoint/Rollerball Pens: Writing Performance and Evaluation

Here, a brief history of the development ballpoint/rollerball pen and fountain is presented. Their principle operation analogous that multipart microfluidics-type devices, where capillarity–gravity drives ink, complex fluid, to flow in confinement micrometer-sized canal or lubricate ball rotating socket. The differences operational writing principles versus are discussed. pen’s manner was monitored using lens end fiber optics digitally recorded. rotation rate per unit length piezoelectric disk oscilloscope technique. role ink (a fluid) chemistry wetting phenomenon elucidated. We also discuss methods for studying evaluating ink–film–ball–paper surface wetting. goal proposed research optimize improve performance pen.