Sanjet BP31 (JS31) Ink Cartridge, Red The Sanjet BP31 Red Ink is excellent for marking porous and non-porous substrates. The Sanjet BP31 dry time is typically instant to a few seconds but can take longer depending on application and environment conditions. Substrates The Sanjet BP31 red ink offers excellent adhesion on glass, plastic, metal, aluminum, concrete, pipe, glossy boxes, film, corrugated boxes, paper, and many other substrates.